WO2026080902A2

WO2026080902A2 - Capturing carbon dioxide

Info

Publication number: WO2026080902A2
Application number: PCT/US2025/050595
Authority: WO
Inventors: Timothy FRAME; Kamil SIMA
Original assignee: Carbon Engineering ULC
Current assignee: Carbon Engineering ULC
Priority date: 2024-10-11
Filing date: 2025-10-10
Publication date: 2026-04-16
Anticipated expiration: 2027-04-11

Abstract

A direct air capture system for capturing carbon dioxide (CO₂) from atmospheric air includes at least one contactor wall, a liquid distribution system, and a regeneration system in fluid communication with the liquid distribution system. The at least one contactor wall includes a plurality of gas-liquid contactors positioned side by side. Each gas-liquid contactor of the plurality of gas-liquid contactors includes a housing, at least one inlet, at least one outlet, at least one packing section disposed between the at least one inlet and the at least one outlet, and a fan. The liquid distribution system includes at least one liquid collection device. The at least one liquid collection device includes a lower liquid collector that includes a floor positioned beneath the packing sections of the plurality of gas-liquid contactors, and a plurality of walls extending upwardly from the floor.

Description

Attorney Docket No.: 30285-0053W01

CAPTURING CARBON DIOXIDE

TECHNICAL FIELD

[0001] This disclosure describes systems, apparatus, and methods for capturing carbon dioxide.

BACKGROUND

[0002] Capturing carbon dioxide (CO2) from the atmosphere is one approach to mitigating greenhouse gas emissions and slowing climate change. However, many technologies designed for CO2 capture from point sources of emissions, such as from flue gas of industrial facilities, are generally ineffective in capturing CO2 from the atmosphere due to the significantly lower CO2 concentrations and large volumes of atmospheric air required to process. In recent years, progress has been made in finding technologies better suited to capture CO2 directly from the atmosphere. Some of these direct air capture (DAC) systems use a solid sorbent where an active agent is attached to a substrate. These DAC systems typically employ a cyclic adsorption-desorption process where, after the solid sorbent is saturated with CO2, it releases the CO2 using a humidity or thermal swing and is regenerated.

[0003] Other DAC systems use a liquid sorbent (sometimes referred to as a solvent) to capture CO2 from the atmosphere. An example of such a DAC system would be one where a fan is used to draw air across a high surface area packing that is wetted with a solution comprising the liquid sorbent. CO2 in the air reacts with the liquid sorbent to generate a CO2 rich solution. The rich solution is processed to regenerate a lean solution and to release a concentrated carbon stream, for example, CO, CO2 or other carbon products.

SUMMARY

[0004] In an example implementation, a direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air includes at least one contactor wall, a liquid distribution system, and a regeneration fluid system. The at least one contactor wall includes a plurality of gas-liquid contactors positioned side by side. The at least one contactor wall extends along a wall axis. Each gas-liquid contactor of the plurality of gas-liquid contactors includes a housing including a plurality of structural members; at least one inlet; at least one outlet spaced apart from the at least one inlet; at least one packing section disposed between the at least one inlet and the at least one outlet; and a fan operable to flow the atmospheric air from the at least one inlet to the at least one outlet and along the at least one packing section. Attorney Docket No.: 30285-0053W01

The liquid distribution system is fluidly coupled to the at least one packing section and operable to flow a CO2 capture solution along the at least one packing section. The CO2 capture solution is configured to absorb CO2 from the atmospheric air. The liquid distribution system includes at least one liquid collection device configured to hold the CO2 capture solution. The at least one liquid collection device includes a lower liquid collector including a floor and a plurality of walls extending upwardly from the floor, the lower liquid collector extending along a collector axis parallel to the wall axis, the floor positioned beneath the packing sections of the plurality of gas-liquid contactors. The regeneration system is in fluid communication with the liquid distribution system to receive the CO2 capture solution, the regeneration system configured to regenerate the CO2 capture solution and form a CCh-lean liquid to return to the plurality of gas-liquid contactors.

[0005] In an aspect combinable with the example implementation, the lower liquid collector has a cross-sectional shape defined in a plane normal to the vertical, the cross- sectional shape forming an H.

[0006] Another aspect combinable with one, some, or all of the previous aspects includes at least one surge tank spaced apart from the at least one contactor wall and in fluid communication with the lower liquid collector.

[0007] In another aspect combinable with one, some, or all of the previous aspects, the at least one liquid collection device includes at least one top basin positioned above the at least one packing section and configured to flow the CO2 capture solution to the at least one packing section.

[0008] In another aspect combinable with one, some, or all of the previous aspects, the at least one packing section includes an upper arrangement of packing and a lower arrangement of packing, the upper and lower arrangements of packing separated by a vertically-extending gap; and the at least one liquid collection device includes at least one redistribution basin positioned in the vertically-extending gap, the at least one redistribution basin configured to receive the CO2 capture solution from the upper arrangement of packing and flow the CO2 capture solution to the lower arrangement of packing.

[0009] In another aspect combinable with one, some, or all of the previous aspects, the regeneration system includes an electrochemical system configured to regenerate the CO2 capture solution and produce a CO2 product stream. The electrochemical system includes a carbonate separation subsystem configured to receive the CO2 capture solution and separate at least a portion of carbonate products from the CO2 capture solution; and an electrochemical cell fluidly coupled to the carbonate separation subsystem. The electrochemical cell is Attorney Docket No.: 30285-0053W01 configured to receive a feed solution and a water stream; and yield at least two product streams including a first product stream that includes the CCh-lean liquid.

[0010] In another aspect combinable with one, some, or all of the previous aspects, the electrochemical cell is configured to yield the CCh-lean liquid including hydroxide for the plurality of gas-liquid contactors.

[0011] In another aspect combinable with one, some, or all of the previous aspects, the CO2 capture solution includes at least one of KOH, NaOH, or a combination thereof.

[0012] In another aspect combinable with one, some, or all of the previous aspects, the regeneration system includes at least one reactor configured to react, via a causticization reaction, slaked lime (Ca(OH)2) and the CO2 capture solution to produce hydroxide and calcium carbonate (CaCCh) solids.

[0013] In another aspect combinable with one, some, or all of the previous aspects, the regeneration system includes a calciner configured to calcine the calcium carbonate solids and produce an exhaust gas stream including a CO2 product stream.

[0014] In another aspect combinable with one, some, or all of the previous aspects, the at least one contactor wall includes a plurality of contactor walls, each contactor wall of the plurality of contactor walls spaced apart from an adjacent contactor wall of the plurality of contactor walls.

[0015] In another aspect combinable with one, some, or all of the previous aspects, the regeneration system is configured to provide a CO2 product stream.

[0016] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector is a collection pan. The collection pan includes a pan floor and a plurality of pan walls, the pan floor perimetrically surrounded by the plurality of pan walls, the pan floor being positioned at a collector height defined from the pan floor to grade.

[0017] In another aspect combinable with one, some, or all of the previous aspects, the structural members extend from the at least one packing section to grade.

[0018] In another aspect combinable with one, some, or all of the previous aspects, the at least one packing section includes a bottom portion defining a bottom area, the pan floor being continuous and defining an area being equal to or greater than the bottom area.

[0019] In another aspect combinable with one, some, or all of the previous aspects, the collection pan includes a plurality of pan sections and the at least one packing section includes a bottom portion defining a bottom area of the at least one packing section, the plurality of pan sections collectively spanning an area equal to or greater than the bottom area. Attorney Docket No.: 30285-0053W01

[0020] Another aspect combinable with one, some, or all of the previous aspects includes a liquid retention system configured to regulate a liquid level in the plurality of gasliquid contactors, the liquid retention system fluidly coupled to the lower liquid collector.

[0021] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector includes a bottom basin. The bottom basin includes a first basin section extending along a first basin section axis parallel to the wall axis; and a second basin section spaced apart horizontally from the first basin section and extending along a second basin section axis parallel to the first basin section axis, the first and second basin sections in fluid communication.

[0022] In another aspect combinable with one, some, or all of the previous aspects, the bottom basin is positioned adjacent to grade.

[0023] In another aspect combinable with one, some, or all of the previous aspects, the first basin section and the second basin section are in fluid communication via a connection section of the bottom basin, the connection section extending between the first and second basin sections.

[0024] In another aspect combinable with one, some, or all of the previous aspects, a floor of the connection section is beneath part of the plenum and a remainder of the floor is offset horizontally from the plenum.

[0025] In another aspect combinable with one, some, or all of the previous aspects, the at least one liquid collection device includes a sump in fluid communication with at least one of the first basin section or the second basin section.

[0026] In another aspect combinable with one, some, or all of the previous aspects, the plenum includes a plenum connection portion above the connection section; a first plenum portion on one side of the plenum connection portion relative to a direction parallel to the wall axis; and a second plenum portion on another side of the plenum connection portion relative to the direction parallel to the wall axis.

[0027] In another aspect combinable with one, some, or all of the previous aspects, the first basin section, the second basin section and the connection section include at least one material of construction; and the first basin section, the second basin section and the connection section delimit a ground area positioned underneath the first plenum portion and underneath the second plenum portion, the ground area being free of the at least one material of construction.

[0028] In another aspect combinable with one, some, or all of the previous aspects, the ground area includes a substrate and a drain in fluid communication with the bottom basin. Attorney Docket No.: 30285-0053W01

[0029] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector has a cross-sectional shape defined in a plane normal to the vertical, the cross-sectional shape forming an H.

[0030] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector includes a first portion extending parallel to the wall axis and a second portion spaced apart horizontally from the first portion and extending parallel to the wall axis, the first and second portions in fluid communication; the floor of the first portion is underneath the first packing sections of the plurality of gas-liquid contactors; and the floor of the second portion is underneath the second packing sections of the plurality of gas-liquid contactors.

[0031] In another aspect combinable with one, some, or all of the previous aspects, each of the first portion and the second portion includes a side extending parallel to the wall axis between opposed ends of the respective portion; and the at least one liquid collection device includes a sump in fluid communication with at least one of the first portion and the second portion, the sump disposed on the side of the at least one of the first portion and the second portion between the opposed ends of the respective portion.

[0032] Another aspect combinable with one, some, or all of the previous aspects includes at least one surge tank spaced apart from the at least one contactor wall and in fluid communication with the lower liquid collector.

[0033] In another aspect combinable with one, some, or all of the previous aspects, at least some structural members of the plurality of structural members are mounted to at least some walls of the plurality of walls.

[0034] In another aspect combinable with one, some, or all of the previous aspects, each of the first packing section and the second packing section define a plenum side facing the plenum, and an outer side opposite to the plenum side along the predominantly horizontal flow direction; the plurality of walls include plenum walls on the plenum side of the first packing section and the second packing section, and outer walls on the outer side of the first packing section and the second packing section; and at least some structural members of the plurality of structural members are mounted to the plenum walls and to the outer walls.

[0035] In another example implementation, a direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air includes at least one contactor wall includes a plurality of gas-liquid contactors positioned side by side and a liquid distribution system. The at least one contactor wall extends along a wall axis. Each gas-liquid contactor of the plurality of gas-liquid contactors includes a housing including a plurality of structural members; at least one inlet; at least one outlet spaced apart from the at least one inlet; at least Attorney Docket No.: 30285-0053W01 one packing section disposed between the at least one inlet and the at least one outlet, and a fan. The at least one packing section includes a first packing section and a second packing section spaced apart from the first packing section by a plenum. The fan is operable to flow the atmospheric air from the at least one inlet, through the first packing section and the second packing section along a predominantly horizontal flow direction, into the plenum, and to the at least one outlet. The liquid distribution system is fluidly coupled to the at least one packing section and operable to flow a CO2 capture solution along a liquid travel dimension, the liquid travel dimension being predominantly vertically downward through the first packing section and through the second packing section. The CO2 capture solution is configured to absorb CO2 from the atmospheric air. The liquid distribution system includes at least one liquid collection device configured to hold the CO2 capture solution The at least one liquid collection device includes a lower liquid collector including a floor and a plurality of walls extending upwardly from the floor, the lower liquid collector extending along a collector axis, the floor positioned beneath the packing sections of the plurality of gas-liquid contactors, at least some of the floor offset horizontally from the plenum.

[0036] In an aspect combinable with the example implementation, the lower liquid collector is a collection pan. The collection pan includes a pan floor and a plurality of pan walls, the pan floor perimetrically surrounded by the plurality of pan walls, the pan floor being positioned at a collector height defined from the pan floor to grade.

[0037] In another aspect combinable with one, some, or all of the previous aspects, the structural members extend from the at least one packing section to grade.

[0038] In another aspect combinable with one, some, or all of the previous aspects, the at least one packing section includes a bottom portion defining a bottom area, the pan floor being continuous and defining an area being equal to or greater than the bottom area.

[0039] In another aspect combinable with one, some, or all of the previous aspects, the collection pan includes a plurality of pan sections and the at least one packing section includes a bottom portion defining a bottom area of the at least one packing section, the plurality of pan sections collectively spanning an area equal to or greater than the bottom area.

[0040] Another aspect combinable with one, some, or all of the previous aspects includes a liquid retention system configured to regulate a liquid level in the plurality of gasliquid contactors, the liquid retention system fluidly coupled to the lower liquid collector.

[0041] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector includes a bottom basin. The bottom basin includes a first basin section extending along a first basin section axis parallel to the wall axis; and a second basin section Attorney Docket No.: 30285-0053W01 spaced apart horizontally from the first basin section and extending along a second basin section axis parallel to the first basin section axis, the first and second basin sections in fluid communication.

[0042] In another aspect combinable with one, some, or all of the previous aspects, the bottom basin is positioned adjacent to grade.

[0043] In another aspect combinable with one, some, or all of the previous aspects, the first basin section and the second basin section are in fluid communication via a connection section of the bottom basin, the connection section extending between the first and second basin sections.

[0044] In another aspect combinable with one, some, or all of the previous aspects, a floor of the connection section is beneath part of the plenum and a remainder of the floor is offset horizontally from the plenum.

[0045] In another aspect combinable with one, some, or all of the previous aspects, the at least one liquid collection device includes a sump in fluid communication with at least one of the first basin section or the second basin section.

[0046] In another aspect combinable with one, some, or all of the previous aspects, the plenum includes a plenum connection portion above the connection section; a first plenum portion on one side of the plenum connection portion relative to a direction parallel to the wall axis; and a second plenum portion on another side of the plenum connection portion relative to the direction parallel to the wall axis.

[0047] In another aspect combinable with one, some, or all of the previous aspects, the first basin section, the second basin section and the connection section include at least one material of construction; and the first basin section, the second basin section and the connection section delimit a ground area positioned underneath the first plenum portion and underneath the second plenum portion, the ground area being free of the at least one material of construction.

[0048] In another aspect combinable with one, some, or all of the previous aspects, the ground area includes a substrate and a drain in fluid communication with the bottom basin.

[0049] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector has a cross-sectional shape defined in a plane normal to the vertical, the cross-sectional shape forming an H.

[0050] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector includes a first portion extending parallel to the wall axis and a second portion spaced apart horizontally from the first portion and extending parallel to the wall axis, Attorney Docket No.: 30285-0053W01 the first and second portions in fluid communication; the floor of the first portion is underneath the first packing sections of the plurality of gas-liquid contactors; and the floor of the second portion is underneath the second packing sections of the plurality of gas-liquid contactors.

[0051] In another aspect combinable with one, some, or all of the previous aspects, each of the first portion and the second portion includes a side extending parallel to the wall axis between opposed ends of the respective portion; and the at least one liquid collection device includes a sump in fluid communication with at least one of the first portion and the second portion, the sump disposed on the side of the at least one of the first portion and the second portion between the opposed ends of the respective portion.

[0052] Another aspect combinable with one, some, or all of the previous aspects includes at least one surge tank spaced apart from the at least one contactor wall and in fluid communication with the lower liquid collector.

[0053] In another aspect combinable with one, some, or all of the previous aspects, at least some structural members of the plurality of structural members are mounted to at least some walls of the plurality of walls.

[0054] In another aspect combinable with one, some, or all of the previous aspects, each of the first packing section and the second packing section define a plenum side facing the plenum, and an outer side opposite to the plenum side along the predominantly horizontal flow direction; the plurality of walls include plenum walls on the plenum side of the first packing section and the second packing section, and outer walls on the outer side of the first packing section and the second packing section; and at least some structural members of the plurality of structural members are mounted to the plenum walls and to the outer walls.

[0055] In another aspect combinable with one, some, or all of the previous aspects, the at least one liquid collection device includes at least one top basin positioned above the at least one packing section and configured to flow the CO2 capture solution to the at least one packing section.

[0056] In another aspect combinable with one, some, or all of the previous aspects, the at least one packing section includes an upper arrangement of packing and a lower arrangement of packing, the upper and lower arrangements of packing separated by a vertically-extending gap; and the at least one liquid collection device includes at least one redistribution basin positioned in the vertically-extending gap, the at least one redistribution basin configured to receive the CO2 capture solution from the upper arrangement of packing, and flow the CO2 capture solution to the lower arrangement of packing. Attorney Docket No.: 30285-0053W01

[0057] In another aspect combinable with one, some, or all of the previous aspects, the at least one contactor wall includes a plurality of dividing walls, each dividing wall of the plurality of dividing walls being upright, the plurality of dividing walls separating at least the plenums of the plurality of gas-liquid contactors of the at least one contactor wall.

[0058] Another aspect combinable with one, some, or all of the previous aspects includes a regeneration system in fluid communication with the liquid distribution system to receive the CO2 capture solution, the regeneration system configured to regenerate the CO2 capture solution and form a CCh-lean liquid to return to the plurality of gas-liquid contactors.

[0059] In another aspect combinable with one, some, or all of the previous aspects, the regeneration system includes an electrochemical system configured to regenerate the CO2 capture solution and produce a CO2 product stream. The electrochemical system includes a carbonate separation subsystem configured to receive the CO2 capture solution and separate at least a portion of carbonate products from the CO2 capture solution; and an electrochemical cell fluidly coupled to the carbonate separation subsystem. The electrochemical cell is configured to receive a feed solution and a water stream; and yield at least two product streams including a first product stream that includes the CCh-lean liquid.

[0060] In another aspect combinable with one, some, or all of the previous aspects, the electrochemical cell is configured to yield the CCh-lean liquid including hydroxide for the plurality of gas-liquid contactors.

[0061] In another aspect combinable with one, some, or all of the previous aspects, the CO2 capture solution includes at least one of: KOH, NaOH, or a combination thereof.

[0062] In another aspect combinable with one, some, or all of the previous aspects, the regeneration system includes at least one reactor configured to react, via a causticization reaction, slaked lime (Ca(OH)2) and the CO2 capture solution to produce hydroxide and calcium carbonate (CaCCh) solids.

[0063] In another aspect combinable with one, some, or all of the previous aspects, the regeneration system includes a calciner configured to calcine the calcium carbonate solids and produce an exhaust gas stream including a CO2 product stream.

[0064] In another aspect combinable with one, some, or all of the previous aspects, the at least one contactor wall includes a plurality of contactor walls, each contactor wall of the plurality of contactor walls spaced apart from an adjacent contactor wall of the plurality of contactor walls.

[0065] In another example implementation, a gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air includes a housing including a plurality of structural Attorney Docket No.: 30285-0053W01 members; at least one inlet; at least one outlet spaced apart from the at least one inlet; at least one packing section disposed between the at least one inlet and the at least one outlet, the at least one packing section including a first packing section and a second packing section spaced apart from the first packing section by a plenum; a fan operable to flow the atmospheric air from the at least one inlet, through the first packing section and the second packing section along a predominantly horizontal flow direction, into the plenum, and to the at least one outlet; and a liquid distribution system fluidly coupled to the at least one packing section and operable to flow a CO2 capture solution along a liquid travel dimension. The liquid travel dimension is predominantly vertically downward through the first packing section and through the second packing section. The CO2 capture solution is configured to absorb CO2 from the atmospheric air. The liquid distribution system includes at least one liquid collection device configured to hold the CO2 capture solution. The at least one liquid collection device includes a lower liquid collector including a floor and a plurality of walls extending upwardly from the floor, the floor positioned beneath the first packing section and the second packing section of the gas-liquid contactor, at least some of the floor offset horizontally from the plenum.

[0066] In an aspect combinable with the example implementation, the lower liquid collector includes a bottom basin, the bottom basin including a first basin section extending along a first basin section axis, and a second basin section spaced apart horizontally from the first basin section and extending along a second basin section axis parallel to the first basin section axis, the first and second basin sections in fluid communication.

[0067] In another aspect combinable with one, some, or all of the previous aspects, the first basin section and the second basin section are in fluid communication via a connection section of the bottom basin, the connection section extending between the first and second basin sections.

[0068] In another aspect combinable with one, some, or all of the previous aspects, the floor of the connection section is beneath part of the plenum and a remainder of the floor is offset horizontally from the plenum.

[0069] In another aspect combinable with one, some, or all of the previous aspects, the at least one liquid collection device includes a sump in fluid communication with at least one of the first basin section and the second basin section.

[0070] In another aspect combinable with one, some, or all of the previous aspects, the plenum includes a plenum connection portion above the connection section; a first plenum portion on one side of the plenum connection portion relative to a direction parallel to a wall Attorney Docket No.: 30285-0053W01 axis, at least one contactor wall extending along a wall axis; and a second plenum portion on another side of the plenum connection portion relative to the direction parallel to the wall axis. [0071] In another aspect combinable with one, some, or all of the previous aspects, the first basin section, the second basin section and the connection section include at least one material of construction; and the first basin section, the second basin section and the connection section delimit a ground area positioned underneath the first plenum portion and underneath the second plenum portion, the ground area being free of the at least one material of construction.

[0072] In another aspect combinable with one, some, or all of the previous aspects, the ground area is defined by a substrate and a drain in fluid communication with the bottom basin. [0073] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector has a cross-sectional shape defined in a plane normal to the vertical, the cross-sectional shape forming an H.

[0074] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector includes a first portion extending parallel to a wall axis, at least one contactor wall extending along a wall axis, and a second portion spaced apart horizontally from the first portion and extending parallel to the wall axis, the first and second portions in fluid communication; the floor of the first portion is underneath the first packing section; and the floor of the second portion is underneath the second packing section.

[0075] In another aspect combinable with one, some, or all of the previous aspects, each of the first portion and the second portion includes a side extending parallel to the wall axis between opposed ends of the respective portion; and the at least one liquid collection device includes a sump in fluid communication with at least one of the first portion and the second portion, the sump disposed on the side of the at least one of the first portion and the second portion between the opposed ends of the respective portion.

[0076] In another aspect combinable with one, some, or all of the previous aspects, at least some structural members of the plurality of structural members are mounted to at least some walls of the plurality of walls.

[0077] In another aspect combinable with one, some, or all of the previous aspects, each of the first packing section and the second packing section define a plenum side facing the plenum and an outer side opposite to the plenum side along the predominantly horizontal flow direction; the plurality of walls include plenum walls on the plenum side of the first packing section and the second packing section and outer walls on the outer side of the first Attorney Docket No.: 30285-0053W01 packing section and the second packing section; and the at least some structural members are mounted to the plenum walls and to the outer walls.

[0078] In another aspect combinable with one, some, or all of the previous aspects, the at least one liquid collection device includes at least one top basin positioned above the at least one packing section and configured to flow the CO2 capture solution to the at least one packing section.

[0079] In another aspect combinable with one, some, or all of the previous aspects, the at least one packing section includes an upper arrangement of packing and a lower arrangement of packing; the upper arrangement of packing and the lower arrangements of packing are separated by a vertically-extending gap; and the at least one liquid collection device includes at least one redistribution basin positioned in the vertically-extending gap, the at least one redistribution basin configured to receive the CO2 capture solution from the upper arrangement of packing, and flow the CO2 capture solution to the lower arrangement of packing.

[0080] In another aspect combinable with one, some, or all of the previous aspects, the lower liquid collector is a collection pan. The collection pan includes a pan floor and a plurality of pan walls, the pan floor perimetrically surrounded by the plurality of pan walls, the pan floor being positioned at a collector height defined from the pan floor to grade.

[0081] In another aspect combinable with one, some, or all of the previous aspects, the structural members extend from the at least one packing section to grade.

[0082] In another aspect combinable with one, some, or all of the previous aspects, the at least one packing section includes a bottom portion defining a bottom area, the pan floor being continuous and defining an area being equal to or greater than the bottom area.

[0083] In another aspect combinable with one, some, or all of the previous aspects, the collection pan includes a plurality of pan sections and the at least one packing section includes a bottom portion defining a bottom area of the at least one packing section, the plurality of pan sections collectively spanning an area equal to or greater than the bottom area.

[0084] Another aspect combinable with one, some, or all of the previous aspects includes a liquid retention system configured to regulate a liquid level in the plurality of gasliquid contactors, the liquid retention system fluidly coupled to the lower liquid collector.

[0085] In another example implementation, a method of capturing carbon dioxide (CO2) from atmospheric air includes flowing the atmospheric air along a first horizontal direction through a first packing section; flowing the atmospheric air along a second horizontal direction through a second packing section, the second horizontal direction being opposite to the first horizontal direction; flowing a CO2 capture solution along the first packing section and Attorney Docket No.: 30285-0053W01 the second packing section to absorb CO2 from the atmospheric air into the CO2 capture solution and to form a CCh-lean gas stream; collecting the CO2 capture solution with a lower liquid collector positioned beneath the first packing section and beneath the second packing section; and flowing the CCh-lean gas stream through a plenum between the first packing section and the second packing section and overlying a ground area spaced horizontally apart from the lower liquid collector.

[0086] In another example implementation, a method of performing maintenance on a gas-liquid contactor includes removing structure delimiting part of a plenum of the gas-liquid contactor to provide access to a ground area delimited by a lower liquid collector of the gasliquid contactor; accessing the ground area; and performing maintenance on components of the gas-liquid contactor from the ground area.

[0087] In another example implementation, a bottom basin of a gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air includes a first basin section extending along a first basin section axis; a second basin section spaced apart from the first basin section and extending along a second basin section axis parallel to the first basin section axis; and a connection section extending between the first basin section and the second basin section and fluidly coupling the first and second basin sections, the connection section positioned underneath some of a plenum of the gas-liquid contactor.

[0088] The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0089] FIG. 1 A shows an example gas-liquid contactor.

[0090] FIGS. 1B-1F are schematic diagrams of example chemical structures.

[0091] FIG. 2 shows an example top view of a bottom basin of the gas-liquid contactor of FIG. 1A.

[0092] FIG. 3A shows another example gas-liquid contactor.

[0093] FIG. 3B shows another example gas-liquid contactor.

[0094] FIG. 3C shows another example gas-liquid contactor.

[0095] FIG. 3D shows another example gas-liquid contactor.

[0096] FIG. 4A is a side elevational view of an example contactor wall of a direct air capture system of the present disclosure. Attorney Docket No.: 30285-0053W01

[0097] FIG. 4B is a top-down view of a direct air capture system of the present disclosure comprising multiple contactor walls.

[0098] FIG. 5A is a perspective view of an example contactor wall of a direct air capture system of the present disclosure.

[0099] FIG. 5B shows portions of an example bottom basin of the present disclosure. [00100] FIG. 6 shows an example top view of a bottom basin of the contactor wall of FIG. 5 A.

[00101] FIG. 7 is a bottom perspective view of another example contactor wall.

[00102] FIG. 8 is a side view of the contactor wall of FIG. 7.

[00103] FIG. 9 is another view of some of the contactor wall of FIG. 7.

[00104] FIG. 10A is a schematic top view of a network of pipes of the contactor wall of

FIG. 7, and of a liquid retention system.

[00105] FIG. 10B is a side elevational view of the liquid retention system of FIG. 10A.

[00106] FIG. 11 is a schematic illustration of a direct air capture system having a gasliquid contactor of the present disclosure.

[00107] FIG. 12 is a schematic illustration of a direct air capture system having a gasliquid contactor of the present disclosure.

[00108] FIG. 13 is a schematic illustration of a direct air capture system having a gasliquid contactor of the present disclosure.

[00109] FIG. 14 is a schematic illustration of a direct air capture system having a gasliquid contactor of the present disclosure.

[00110] FIG. 15 is a schematic flow diagram of a method of capturing CO2 from atmospheric air.

[00111] FIG. 16 is a schematic flow diagram of a method of performing maintenance on a gas-liquid contactor.

[00112] FIG. 17 is a schematic diagram of a control system (or controller) for a gasliquid contactor of the present disclosure.

[00113] FIG. 18 is a schematic illustration of a direct air capture system having a gasliquid contactor of the present disclosure.

DETAILED DESCRIPTION

[00114] Referring to FIG. 1 A, the present disclosure describes systems and methods for capturing carbon dioxide (CO2) from a dilute gas source with a gas-liquid contactor 100 that can be part of a capture system such as a Direct Air Capture (DAC) system. A dilute gas source Attorney Docket No.: 30285-0053W01 can include the atmosphere (e.g., ambient or atmospheric air) or another fluid source that contains dilute concentrations of CO2. Dilute concentrations of CO2, for example in the atmosphere are in the range of 400-420 parts per million (“ppm”) or approximately 0.04- 0.042% v/v, and less than 1% v/v. These dilute concentrations of CO2 are at least one order of magnitude lower than the concentration of CO2 in point-source emissions, such as flue gases, where point-source emissions can have concentrations of CO2 ranging from 1.5-15% v/v, or from 5-15% v/v depending on the source of emissions.

[00115] In example implementations, the gas-liquid contactor 100 is operated to capture the CO2 present in the dilute gas source, being for example ambient air by ingesting the ambient air as a flow of CCh-laden air 101, and by treating the CCh-laden air 101 so as to transfer CO2 present therein via absorption to a CO2 capture solution 114 which includes at least one CO2 capture species, also being referred to as a CO2 sorbent via absorption. Some or all of the CO2 in the CCh-laden air 101 is removed by absorption into the CO2 capture solution 114 and further reaction with the at least one CO2 capture species. The treated CCh-laden air 101 is then discharged by the gas-liquid contactor 100 as a flow of CCh-lean gas 105 (or, CO2-IOW air). In operating to treat atmospheric air in this manner, the gas-liquid contactor 100 can sometimes be referred to herein as an “air contactor” because it facilitates absorption of CO2 from the atmospheric air into the CO2 capture solution 114. In contrast to water cooling towers which function primarily to transfer heat between water and atmospheric air, the gas-liquid contactor 100 functions primarily to achieve mass transfer of CO2 from the atmospheric air to the CO2 capture solution 114. In operating in this manner, the gas-liquid contactor 100 can be used as part of a DAC system 1200, 1300, 1400, 1500, described in greater detail below in reference to FIGS. 11-14 and 18.

[00116] In example implementations, at a given reference temperature, the density of the CO2 capture solution 114 is greater than the density of water at the same reference temperature. At comparable reference temperatures, in example implementations, the density of the CO2 capture solution 114 is at least 10% greater than the density of water. In example implementations, at comparable reference temperatures, the density of the CO2 capture solution 114 is approximately 10% greater than the density of water. The density and the viscosity of the CO2 capture solution 114 can vary depending on the composition of the CO2 capture solution 114 and the temperature. For example, at temperatures of 0°C to 20°C, the CO2 capture solution 114 can comprise 1 M KOH and 0.5 M K2CO3 and can have a density ranging from 1115 kg/m³ - 1119 kg/m³ and a viscosity ranging from 1.3 mPa-s - 2.3 mPa-s. In another example, at temperatures of 20°C to 0°C, the CO2 capture solution 114 can comprise 2 M KOH Attorney Docket No.: 30285-0053W01 and 1 M K2CO3, and can have a density ranging from 1260 kg/m³ - 1266 kg/m³ and a viscosity ranging from 1.8 mPa-s - 3.1 mPa-s. In comparison, water has a density of 998 kg/m³ and viscosity of 1 mPa-s at 20°C.

[00117] In example implementations, and referring to FIG. 1 A, CO2 from the CCh-laden air 101 is captured by contacting the CCh-laden air 101 with the CO2 capture solution 114 in the gas-liquid contactor 100 for absorption of the CO2. Reacting the absorbed CO2 from the CCh-laden air 101 with one or more CO2 capture species in the CO2 capture solution 114 results in the production of a CCh-laden capture solution 111 including captured CO2, for example as carbonate, carbamate and/or carbamic acid species. Carbonate species can include solid carbonates, carbonate ions and bicarbonate ions. The composition of the CCh-laden capture solution 111 can vary in accordance with several factors including the nature of the CO2 capture solution 114 and the operational absorption conditions. The CCh-laden capture solution 111 can also be referred to as, for example, a carbonate-rich capture solution 111 or a CCh-rich capture solution 111.

[00118] In example implementations, and referring to FIG. 1 A, the CO2 capture solution 114 is a caustic solution. In example implementations, the CO2 capture solution 114 has a pH of 10 or higher. In example implementations, the CO2 capture solution 114 has a pH of approximately 14. Non-limiting examples of the CO2 capture solution 114 include aqueous solutions of an alkali metal sorbent, such as alkali metal hydroxide (e.g., KOH, NaOH, or a combination thereof), aqueous amine solutions, aqueous amino acid salt solutions, nonaqueous amine solutions, non-aqueous organic liquids/solutions (e.g., dimethyl sulfoxide or DMSO), aqueous guanidinium solutions, aqueous aminosilicone solutions, aqueous amidine solutions, non-aqueous phosphazene solutions, aqueous amines slurries with MOF, aqueous slurries with amine polymers, aqueous carbonate and/or bicarbonate solutions, aqueous phenoxi de/phenoxi de salt solutions, ionic liquids, non-aqueous solvents, , or a combination thereof. In example implementations, the solvent of the CO2 capture solution 114 has a higher vapour pressure than that of the CO2 capture species to facilitate regeneration of the CO2 capture solution 114.

In example implementations, the CO2 capture solution 114 can include an unsaturated nitrogenous compound, such as a guanidine-based capture species as the at least one CO2 capture species, for example an aminoguanidine or an iminoguanidine. Non-limiting examples of the guanidine-based capture species of the CCh-capture solution 114 include bis- iminoguanidines. Examples of bis-iminoguanidines include 2,5-furan-bis(iminoguanidine) (FuBIG) whose chemical structure is shown in FIG. IB as chemical structure 150. Attomey Docket No.: 30285-0053W01

Non-limiting examples of amine-based capture species of the CCh-capture solution 114 include an imine, an amidine, an amine, a hindered or non-hindered amine group having alkanolamine and alcoholic hydroxyl, carbonyl or carboxyl groups, or a combination thereof. Non-limiting examples of amines have at least one amino group (monoamine), at least two amino groups (diamine), at least three amino groups (triamine) or more amino groups (multiamine).

[00119] In example implementations, the CO2 capture solution 114 can include a diamine as the at least one CO2 capture species, for example a diamine with an aminocyclic compound group. For example, the at least one CO2 capture species can include cyclopentane- 1,3-diamine (being functionalized or not). For example, the aminocyclic compound group can be an aminocyclohexyl group. For example, the at least one CO2 capture species can include a diamine including a cyclic compound being functionalized by a hydrocarbon chain (R). For example, the at least one CO2 capture species can include a diamine including a cyclic compound being functionalized by a functional group (X). For example, the at least one CO2 capture species can include a diamine including a cyclic compound being functionalized by two amino groups in a first and third position of the cyclic compound, and by a hydrocarbon chain (R) and/or a functional group (X) at another position of the cyclic compound (e.g., cyclohexane- 1,3 -diamine-5 R X). The hydrocarbon chain R can be straight or branched, with or without rings, and can vary in length. The functional group X can functionalize the cyclic compound and/or the hydrocarbon chain R. The functional group X can be, without being limited to, alcohol, amine, amide, carboxylic acid, ester, ether, halogen, metal, or any combinations thereof. Both the hydrocarbon chain R and the functional group X can exist independently or together at a same position of the cyclic compound (e.g., fifth position of a cyclohexane ring), or at other positions of the cyclic compound. For example, the at least one CO2 capture species can include cyclohexane- 1,3 -diamine. For example, the at least one CO2 capture species can include a cyclohexane- 1,3 -diamine-5 R X, where R is butane and X is an amino group, such as cyclohexane-l,3-diamine-5-normal-butane-amine. For example, the at least one CO2 capture species can include a cyclohexane-l,3-diamine-5 R X, where R is hexane and X is absent, such as cyclohexane-l,3-diamine-5-normal-hexane. For example, the at least one CO2 capture species can include 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine, also referred to as isophorone diamine or IPDA whose chemical structure is shown in FIG. 1C as chemical structure 151.

[00120] Examples of the alkanolamine include monoethanolamine (MEA), diethanolamine, triethanolamine, methyldiethanolamine, diisopropanolamine, and diglycolamine. Examples of the hindered amine having alcoholic hydroxyl include 2-amino- Attorney Docket No.: 30285-0053W01

2 -methyl- 1 -propanol (AMP) whose chemical structure is shown in FIG. ID as chemical structure 152. Another example is 2-(ethylamino)-ethanol (EAE) whose chemical structure is shown in FIG. IE as chemical structure 153. Another example is 2-(methylamino)-ethanol (MAE) whose chemical structure is shown in FIG. IF as chemical structure 154.

[00121] The capture kinetics of capturing CO2 from the C Ch-laden air 101 to form carbonate can be improved by the introduction of an additive such as a promoter species in the CO2 capture solution 114. In example implementations, the resulting carbonate-rich capture solution 114 produced by the capture sections 102 A, 102B includes carbonates and bicarbonates and includes the promoter as well. An example composition of such a carbonate- rich capture solution 114 can include K2CO3/KHCO3 and a promoter. Non-limiting examples of promoters include carbonic anhydrase, amines (primary, secondary, tertiary), zwitterionic amino acids, and boric acid. Non-limiting examples of additives include chlorides, sulfates, acetates, phosphates, surfactants, oxides and metal oxides. The carbonate-rich capture solution 114 (sometimes referred to herein as a “CCh-rich capture solution 107”) resulting from such a CO2 capture solution 106 can have a pH in the range of 11-13 and can have little residual hydroxide from the CO2 capture solution 114. In example implementations, additives that are not considered promoters can be used to improve the uptake of CO2 in the CO2 capture solution 114. For example, a surfactant can be added to the CO2 capture solution 114 to lower the surface tension of the CO2 capture solution 114 to improve the ability of the CO2 capture solution 114 to wet the material of a gas-liquid interface. Non-limiting examples of rateenhancing additives include carbonic anhydrase, piperazine, monoethanolamine (MEA), diethanolamine (DEA), zinc triazacycles, zinc tetraazacycles, copper glycinates, hydroxopentaaminecobalt perchlorate, formaldehyde hydrate, saccharose, fructose, glucose, phenols, phenolates, glycerin, arsenite, vanadium pentoxide, hypochlorite, hypobromite, or other oxyanionic species. For example, in implementations of the present disclosure where the at least one CO2 capture solution 114 includes one or more alakali hydroxides, CO2 is absorbed in the CO2 capture solution 114 and reacted with the one or more alkali hydroxides to form the carbonate-rich capture solution 111 (e.g., including K2CO3, Na2CC>3, or a combination thereof). In example implementations, the CO2 capture solution 114 includes two or more alkali hydroxides, including a first hydroxide MOH and a second hydroxide YOH, where “M” represents one of the alkali metals and “Y” represents a different alkali metal. M and/or Y of the CO2 capture solution 114 reacts with the absorbed CO2 of the CO2-laden air 101 to form two or more carbonate compounds in the CO2-laden capture solution 111, including a first carbonate M2CO3 and a second carbonate Y2CO3 (e.g., K2CO3, Na2CO3, Li2CO3, CS2CO3, Attorney Docket No.: 30285-0053W01 and/or a combination thereof). The CCh-rich capture solution 111 is a carbonate-rich capture solution being an aqueous mixture comprising carbonate ions, alkaline metal carbonates (e.g., K2CO3, Na2CC>3, Li2CC>3, CS2CO3, and/or a combination thereof), hydroxide, or a combination thereof. The carbonates can be carbonate solids such that the carbonate-rich capture solution 111 forms a pumpable slurry.

[00122] For example, in implementations of the present disclosure where the at least one

CO2 capture species comprises an amine, CO2 is absorbed in the CO2 capture solution 114 and reacted with the amine to form the CCh-rich capture solution 111 which includes solids. Solids including carbamate solids, carbonate solids and carbamic acid solids can be referred to as carbon containing solids. In one example of such an implementation, the at least one CO2 capture species of the CO2 capture solution 114 includes isophorone diamine (IPDA), and CO2 is reacted with the amine to form the CCh-rich capture solution 114 which includes at least one of carbamic acid species, carbamate species and carbonate species (e.g., including carbamic acid solids). Depending on the solvent (aqueous and non-aqueous) of the CO2 capture solution 114, carbamic acid solids can be insoluble, such that the CCh-rich capture solution 114 forms a pumpable slurry.

[00123] For example, in implementations of the present disclosure where at least one CO2 capture species of the CO2 capture solution 114 is an alkali hydroxide (e.g., KOH), the carbonates (e.g., K2CO3, KHCO3, etc.) formed within the CO2-rich capture solution 114 can be reacted with another species such as an amine species. In example implementations, the amine species is IPDA. A solid precipitate resulting from the reaction, including solids such as carbamic acid solids, can be used to recover at least some of the CO2 captured from the dilute gas source. In such implementations of using two or more CO2 capture species, the CO2 capture process can benefit from the comparatively favourable capture kinetics associated with inorganic capture species such as alkali hydroxides, while also benefiting from the favorable regeneration kinetics associated with organic capture species, for example. The additional chemical compounds may promote the precipitation of solids associated with the alkali hydroxide (e.g., KOH). Additional CO2-capture species that can be used, in combination with a first CO2-capture species, to precipitate solids from dissolved species include, but are not limited to at least one of a cyclic diamine or a bis-iminoguanidine. The additional chemical compounds may promote the precipitation of solids associated with the alkali hydroxide (ex: KOH) or hindered amine.

[00124] The CO2-laden capture solution 111 can also include other components in smaller amounts, such as hydroxide ions, alkali metal hydroxide (e.g., KOH, NaOH), water, Attorney Docket No.: 30285-0053W01 and impurities. For example, the carbonate-rich capture solution 111 can comprise between 0.4 M to 6 M K2CO3 and between 1 M to 10 M KOH. In another implementation, the carbonate-rich capture solution 111 can comprise an aqueous Na2CO3-NaOH mixture. In example implementations, the carbonate-rich capture solution 111 can comprise a mixture of K2CO3 and Na₂CO₃.

[00125] The capture kinetics of capturing CO2 from the CO2-laden air 101 to form carbonate can be improved by the introduction of an additive such as a promoter species in the CO2 capture solution 114. Non-limiting examples of promoters for boosting CO2 capture with carbonate include carbonic anhydrase, amines (primary, secondary, tertiary), zwitterionic amino acids, and boric acid. The resulting carbonate-rich capture solution 111 produced by the gas-liquid contactor 100 includes carbonates and bicarbonates and includes the promoter as well. An example composition of such a carbonate-rich capture solution 111 can include K2CO3/KHCO3 and a promoter. The carbonate-rich capture solution 111 resulting from such a CO2 capture solution 114 can have a pH in the range of 11-13 and can have little residual hydroxide from the CO2 capture solution 114. In some cases, additives that are not considered promoters can be used to improve the uptake of CO2 in the CO2 capture solution 114.

[00126] Referring to FIG. 1 A, the gas-liquid contactor 100 includes a housing 102. The housing 102 defines part of the corpus of the gas-liquid contactor 100 and provides structure thereto. The housing 102 includes exterior structure or walls that partially enclose any combination of interconnected structural members 115. The structural members 115 provide structural support and stability to the gas-liquid contactor 100 and provide a body for supporting components of the gas-liquid contactor 100 within the housing 102. The structural members 115 can include, but are not limited to, walls, panels, beams, frames, etc. The housing 102 can include other components as well, such as walls, cladding, panels, etc. which help to close off parts of the housing 102 and define the enclosure of the housing 102. The housing 102 at least partially encloses and defines an interior 113 of the housing 102. The interior 113 of the housing 102 is an inner volume or inner space in which components of the gas-liquid contactor 100 are positioned. The housing 102 also includes openings 103 that allow for movement of gases into and out of the gas-liquid contactor 100. For example, and referring to FIG. 1 A, the housing 102 has one or more inlet(s) 1031. In the implementation of FIG. 1 A, the one or more inlet(s) 1031 are formed by the openings 103, such that the inlet(s) 1031 can be referred to herein as one or more inlet opening(s) 1031 through which the CCh-laden air 101 enters the interior 113 of the housing 102. The housing 102 has one or more outlet(s) 1030. In the implementation of FIG. 1A, the one or more outlet(s) 1030 are formed by the openings Attorney Docket No.: 30285-0053W01

103, such that the outlet(s) 1030 can be referred to herein as one or more outlet opening(s) 1030 through which the CO2-lean gas 105 exits the interior 113 of the housing 102.

[00127] In the example implementation of the gas-liquid contactor 100 of FIG. 1A, the housing 102 defines two inlets 1031 and one outlet 1030. The outlet 1030 can be defined by a component of the gas-liquid contactor 100. For example, in the implementation of the gasliquid contactor 100 of FIG. 1 A, the gas-liquid contactor 100 has a fan stack 107 with an upright orientation. The fan stack 107 extends upwardly from the housing 102 and helps to discharge the CCh-lean gas 105. The outlet 1030 is positioned along the fan stack 107. In such an implementation, the CO2-laden air 101 enters the interior 113 of the housing 102 along a substantially horizontal direction through one or both of the inlets 1031, and the CO2-lean gas 105 exits the interior 113 along a substantially vertical direction through the outlet 1030. The outlet 1030 is located at the upper extremity of the fan stack 107. In implementations of the gas-liquid contactor 100 without a fan stack 107, the outlet 1030 can be located elsewhere. Other configurations for the inlets 1031 and outlets 1030 of the housing 102 are possible.

[00128] The housing 102 at least partially encloses and protects components of the gasliquid contactor 100 positioned in the interior 113 of the housing 102. One example of such a component is a packing section 106, which is protected from the surrounding atmosphere by the housing 102. As can be seen in FIG. 1A, one or more packing sections 106, which are sometimes referred to herein collectively as “fill 106” or “packing 106,” are located within the interior 113 in a position adjacent to the one or more inlets 1031. In this position, the one or more packing sections 106 receive the CCh-laden air 101 which enters the interior 113 via the one or more inlets 1031.

[00129] The one or more packing sections 106 function to increase transfer of CO2 present in the CC -laden air 101 to a flow of the capture solution 114, in that the one or more packing sections 106 provide a large surface area for the capture solution 114 to disperse on, thereby increasing the reactive area between the CCh-laden air 101 and the capture solution 114. The capture solution 114 transforms the CCh-laden air 101 into the CCh-lean gas 105 which is discharged from the one or more outlet(s) 1030 of the gas-liquid contactor 100. The packing sections 106 receives the CO2 capture solution 114 and facilitates absorption of the CO2 present in the CO2-laden air 101 into the CO2 capture solution 114 on the packing sections 106, as described in greater detail below.

[00130] Referring to FIG. 1A, one possible arrangement of the packing sections 106 includes two or more packing sections 106A, 106B. Each packing section 106A, 106B is positioned adjacent to and downstream of one of the inlets 1031, relative to a flow direction of Attorney Docket No.: 30285-0053W01 the CCh-laden air 101 through the inlets 1031. The packing sections 106A, 106B are spaced apart from each other within the housing 102. The direction along which the packing sections 106A, 106B are spaced apart is parallel to the direction along which the CCh-laden air 101 flows through the packing sections 106 A, 106B. The space or volume defined between the packing sections 106A, 106B and/or one or more structural members of the housing 102 is a plenum 108. The plenum 108 is flanked by the packing sections 106A, 106B. The plenum 108 is a void or space within the housing 102 into which gases flow from the packing sections 106A, 106B (e.g., the CCh-lean gas 105), and from which the CCh-lean gas 105 flows out of the housing 102 through the outlet 1030. The plenum 108 is part of the interior 113 of the housing 102. The volume of the plenum 108 is less than a volume of the interior 113. In example implementations, the volume of the interior 113 of the housing 102 is approximately equal to the combined volume of the packing sections 106 A, 106B and the plenum 108. Referring to FIG. 1 A, the packing sections 106 A, 106B are positioned along the same level, or are positioned along the same lower horizontal plane, as the plenum 108.

[00131] Referring to FIG. 1A, the plenum 108 can include an upper plenum portion 108U that is an uppermost portion of the plenum 108, and a lower plenum portion 108L that is a lowermost portion of the plenum 108. A total height of the plenum 108 is defined as the height of the upper plenum portion 108U plus the height of the lower plenum portion 108L. Part of the upper plenum portion 108U is defined by housing plenum walls 102W of the housing 102, and a remainder of the upper plenum portion 108U is defined by the portion of the fan stack 107 positioned beneath the fan 121. The housing plenum walls 102W extend upwardly from a remainder of the housing 102. In some embodiments, and referring to FIG. 1 A, the housing plenum walls 102W are the uppermost portion of the housing 102. The height of the upper plenum portion 108U includes a lower height portion defined by the housing plenum walls 102W, and an upper height portion defined by the portion of the fan stack 107 positioned beneath a fan 121. The plenum 108 is beneath the fan 121. Referring to FIG. 1A, part of the upper plenum portion 108U, and thus part of the plenum 108, extends into the fan stack 107 or cowling. After the CCh-laden air 101 flows through the packing sections 106A, 106B, the CCh-lean gas 105 flows through the plenum 108 before being discharged to the ambient environment. In other implementations of the gas-liquid contactor 100, the plenum is absent.

[00132] In the example implementation of the gas-liquid contactor 100 of FIG. 1A, the CCh-laden air 101 enters the interior 113 of the housing 102 along a substantially horizontal direction through both of the inlets 1031. The CCh-laden air 101 then flows through the packing Attorney Docket No.: 30285-0053W01 sections 106A, 106B along a substantially horizontal direction, where the CO2 present in the CCh-laden air 101 contacts the CO2 capture solution 114 present on the packing sections 106 A, 106B and/or flowing in a substantially downward direction over the packing sections 106A, 106B. The exposed surface of the liquid film on the packing sections 106A, 106B is a gasliquid interface between the CCh-laden air 101 and the CO2 capture solution 114. CO2 from the CCh-laden air 101 is absorbed into the liquid film to form the CCh-laden capture solution 111 and the CCh-lean gas 105. The CCh-laden capture solution 111 flows downwardly off the packing sections 106 A, 106B in a mixed solution with unreacted CO2 capture solution 114 and is collected. The CCh-laden air 101 treated by the packing sections 106A, 106B exits the packing sections 106 A, 106B as the CCh-lean gas 105. The CCh-lean gas 105 from both packing sections 106 A, 106B converges in the plenum 108, and then flows in a vertically upward direction out of the plenum 108 through the outlet 1030. The gas-liquid contactor 100 of FIG. 1A can be considered a dual-cell, cross-flow air contactor, where each cell is defined as the portion of the gas-liquid contactor 100 having one of the packing sections 106 A, 106B. Other configurations of a gas-liquid contactor are possible, as described in greater detail below. [00133] In example implementations, and referring to FIG. 1 A, the CO2-lean gas stream 105 can contain components of the CO2 capture solution 114, and possibly also components of the CO2-laden capture solution 111. The components of the CO2 capture solution 114 and possibly also of the CCh-laden capture solution 111 can be in liquid and/or vapour phase and may be present in the flow of the CCh-lean gas stream 105 such that they can flow with the CCh-lean gas stream 105 out of the gas-liquid contactor 101. The components in the CCh-lean gas stream 105 can include, but are not limited to, alkali hydroxides, carbonic anhydrase, amines (primary, secondary, tertiary), carbonates and bicarbonates. The size and phase of the components can vary based on numerous factors, non-limiting examples of which include the physical and/or chemical properties of the CO2 capture solution 114, ambient and/or solution temperature, and the relative humidity of ambient and/or of the CCh-laden air 101.

[00134] For example, in implementations where the capture species of the CO2 capture solution 114 includes one or more amine species, the components can include volatilized amine components which are in vapour or gas phase and are in equilibrium with the CCh-lean gas stream 105, due to the volatility of the amine species resulting from its high vapour pressure at most ambient conditions. In some examples, in implementations of the present disclosure where the capture species of the CO2 capture solution 114 includes one or more alkali hydroxides species, the components can be in liquid phase as liquid airborne particles and can be entrained by, or suspended in, the CCh-lean gas stream 105, due to the comparatively low Attorney Docket No.: 30285-0053W01 volatility of the alkali hydroxide species resulting from its relatively low vapour pressure at most ambient conditions. In some examples, in implementations of the present disclosure where the capture species of the CO2 capture solution 114 includes bicarbonate species, the components can be in liquid phase as liquid airborne particles and can be entrained by, or suspended in, the CCh-lean gas stream 105, due to the comparatively low volatility of the bicarbonate species resulting from its relatively low vapour pressure at most ambient conditions. In some examples, in implementations of the present disclosure where the capture species of the CO2 capture solution 114 includes two or more species which have both high and low volatilities, the components can be in both vapour phase, and liquid phase as liquid airborne particles. In such examples of liquid airborne particles, the airborne particles can be liquid aerosol particles of the CO2 capture solution 114 that are suspended in the CCh-lean gas stream 105 and can range in size from less than 1 micron to over 70 microns. In such examples of liquid aerosol particles, the liquid aerosol particles of the CO2 capture solution 114 that are suspended in the CCh-lean gas stream 105 can have a size less than 2.5 microns.

[00135] Solid airborne particles can also be entrained in the CCh-lean gas stream 105. Depending on such non-limiting factors as the physical and/or chemical properties of the CO2 capture solution 114, the reaction products of the CO2 capture solution 114 with CO2, the solids present in liquid flows returning to the gas-liquid contactor 101, and the environment in which the gas-liquid contactor 101 is operating, solid airborne particles can be suspended in the CO2- lean gas stream 105 flowing from the gas-liquid contactor 101. Such solid airborne particles can be, or can include, non-process elements (NPEs) which are desirable to remove from the gas flows exiting the gas-liquid contactor 101. The present disclosure describes measures to reduce or eliminate these solid airborne particles, as described in greater detail below.

[00136] Referring to FIG. 1A, the gas-liquid contactor 100 can include one or more portions of drift eliminators 117 to remove or reduce one or more of the CO2 capture solution 114, the CCh-laden capture solution 111 and solid airborne particles that may be entrained in the CCh-lean gas 105 and exhausted from the outlet 1030. The CO2 capture solution 114 and/or the CO2-laden capture solution 111 entrained in the CO2-lean gas 105 can be referred to as “drift” or “mist,” and can be in liquid aerosol form or as volatilized components. The drift eliminators 117 (sometimes referred to as “mist eliminators”) are positioned downstream of the packing 106 relative to a flow direction of the CCh-laden air 101, and function to eliminate drift (i.e., remove 100% of aerosolized or volatilized particles) or to reduce the amount of drift (i.e., remove less than 100% of aerosolized or volatilized particles) exiting the gas-liquid contactor 100 through the outlet 1030. For example, in implementations where the capture Attorney Docket No.: 30285-0053W01 species of the CO2 capture solution 114 includes one or more amine species, the drift eliminators 117 help to remove or reduce the volatilized amine components from the CCL-lean gas stream 105. For example, in implementations where the capture species of the CO2 capture solution 114 includes one or more hydroxides, the drift eliminators 117 help to remove or reduce the liquid aerosol components from the CCh-lean gas stream 105. The drift eliminators 117 may include componentry of the passive type, of the active type, or both. Non-limiting examples of passive componentry for the drift eliminators 117 include baffles, vanes, slats, and packing material. Non-limiting examples of active componentry for the drift eliminators 117 include wash or scrubbing componentry, and electrostatic componentry. The drift eliminators 117 can include both passive and active componentry, in any combination.

[00137] Each packing section 106 defines a packing depth 106D, which represents the distance traversed by the CCL-laden air 101 as it flows through the packing section 106. The packing depth 106D is sometimes referred to as the air travel depth (or “ATD”) of the packing section 106. The packing depth 106D can be in the range of 2-10 meters. Each packing section 106 also defines a packing liquid travel dimension 106L (sometimes referred to herein as the “packing LTD 106L”), which represents the distance traversed by the capture solution 114 as it flows through the packing section 106. In the gas-liquid contactor 100 of FIG. 1A, the packing depth 106D is transverse to the packing LTD 106L. In the gas-liquid contactor 100 of FIG. 1A, the packing depth 106D is defined along a substantially horizontal direction, and the packing LTD 106L is a vertical dimension. In example implementations, the packing LTD 106L (e.g., the height of each packing section 106) is greater than 2 m. In example implementations, the packing LTD 106L is greater than 5 m. In example implementations, the packing LTD 106L is between 2 m and 20 m. In example implementations, the packing depth 106D is greater than 3 m. In example implementations, the packing depth 106D is greater than 5 m. In example implementations, the packing depth 106D is between 3 m and 10 m. In other configurations of the gas-liquid contactor 100, the packing depth 106D and the packing LTD 106L can be defined differently, as described in greater detail below.

[00138] Referring to FIG. 1 A, each packing section 106 includes one or more structured packings 116. In the implementation of the packing sections 106 of FIG. 1A, each packing section 106 includes multiple structured packings 116. Within one of the packing sections 106, each structured packing 116 is arranged adjacent to another structured packing 116. The structured packings 116 of each packing section 106 can be arranged adjacent to each other in the direction of one or more of the packing depth 106D, the packing LTD 106L, and a direction perpendicular to both of the packing depth 106D and the packing LTD 106L. Within one of Attorney Docket No.: 30285-0053W01 the packing sections 106, in example implementations one structured packing 116 is attached to another structured packing 116. Within one of the packing sections 106, in example implementations the structured packings 116 of each packing section 106 are arranged next to one another with minimal separation or gaps along one or more of the packing depth 106D, the packing LTD 106L, and a direction perpendicular to both of the packing depth 106D and the packing LTD 106L.

[00139] Referring to FIG. 1A, some of the structured packings 116 of each packing section 106 are mounted to one or both of: 1) a structural member 115 of the housing 102, and 2) at least one other structured packing 116. This support of the structured packings 116 reinforces their arrangement within each packing section 106, helps to rigidify each packing section 106, and can also help each structured packing 116 resist or support loads acting upon it during operation of the gas-liquid contactor 100. For example, in mounting the structured packings 116 as described above, the structured packings 116 become constrained which can result in an increase in the overall strength (e.g., crush strength) of each structured packing 116 and of each packing section 106, compared to a packing structure that is unconstrained.

[00140] Referring to FIG. 1 A, each structured packing 116 includes, or is composed of, multiple packing sheets 130 attached together to form a three-dimensional structured packing 116. The packing sheets 130 of each structured packing 116 can be made of any suitable material, or have any suitable configuration, to achieve the function ascribed to the packing sections 106 herein. Some or all of the packing sheets 130 can be made from PVC, which is relatively light, moldable, affordable, and resists degradation caused by many chemicals. The packing sheets 130 are arranged, constructed, treated or otherwise configured to promote spreading of the liquid CO2 capture solution 114 into a thin film on the surfaces of the packing sheets 130, which can enable maximum exposure of the liquid CO2 capture solution 114 to the CO2 present in the CCh-laden air 101. For example, the liquid-gas interface surface of one or more of the packing sheets 130 can be treated with a coating, have shapes or formations, and/or be made of a material that vary the surface energy (e.g., increase the surface energy) of portions of the packing sheet 130 and/or lower the contact angle of the liquid CO2 capture solution 114. For example, the hydrophilicity of the liquid-gas interface surface of one or more of the packing sheets 130 can be increased by applying a coating to increase the surface free energy. Coatings can be applied to some or all of the structured packing 116 to make the structured packing 116 even more suitable for low liquid loading rates ranging from 0.5 L/m²s to 2.5 L/m²s. In this regard, reference is made to such surface treatments and modifications described in U.S. Patent Application Publication No. 2022/0176312, the entire contents of which are incorporated Attorney Docket No.: 30285-0053W01 herein by reference. Such “film-type” packing sheets 130 are suitable for DAC applications since they have the capacity for effective mass transfer per unit volume of fill space. For example, film-type fill offers a relatively high ratio of specific surface area to volume, the ratio defined in units of m²/m³. A high specific surface area helps to expose more CO2 to the surface of the CO2 capture solution 114, and also has cost and structural implications. Each packing sheet 130 supports and directs the CO2 capture solution 114 as it flows along the packing sheet 130.

[00141] Each packing sheet 130 is shaped, sized, formed, and configured to assist with the transfer of CO2 from the CCh-laden air 101 to the CO2 capture solution 114. Each packing sheet 130 is thus a medium intended to optimise CO2 from the flowing atmospheric air being absorbed into the flowing CO2 capture solution 114. Other fill sheets, for example, those used in water cooling tower applications, function primarily to transfer heat between water and atmospheric air, with little or no mass transfer occurring between the constituent gases of the air flow and the water being cooled. By optimizing for the mass transfer of CO2, the packing sheet 130 can be able to achieve lower pressure losses of air flowing across the packing sheet 130 and more optimal distribution of the CO2 capture solution 114, compared to if the mass transfer of CO2 was attempted with a fill sheet optimised for heat transfer. The packing sheet 130 can be referred to using other terms similar to “sheet,” such as panel, pane, plate, and layer. The packing sheet 130 in some cross-flow implementations is also shaped, sized, formed, and configured to assist with the transfer of CO2 from the CCE-laden air 101 to the CO2 capture solution 114 at low liquid loading rates (e.g., 0.5 L/m²s to 2.5 L/m²s) compared to the higher liquid loading rates (often greater than 15 L/m²s) of cross-flow water cooling tower applications.

[00142] In the structured packing 116 of FIG. 1A, all the packing sheets 130 are identical. In example implementations, one or more of the packing sheets 130 of the structured packing 116 is different from another packing sheet 130 of the structured packing 116. In an example implementation, one or more of the packing sheets 130 is optimised for minimal pressure drop across the packing sheet 130, while another one of the packing sheets 130 is optimised for stiffening or being resisting to crushing. Features of the packing sheet 130 can be selected to optimise for mass-transfer capture efficiency, reduced pressure drop, and improved surface wetting, among other possible parameters.

[00143] Different, or additional, componentry to the structured packing 116 can be used to form each packing section 106. For example, in example implementations, one or more of the packing sections 106 are formed of random packing (also referred to as dumped or non Attorney Docket No.: 30285-0053W01 structured packing). In example implementations, one or more of the packing sections 106 includes both structured packing and random packing. In example implementations, one or more of the packing sections 106 is formed of one or more styles of random packing that are positioned in tiers of packing. In example implementations, one or more of the packing sections 106 includes corrugated packing. In example implementations, one or more of the packing sections 106 includes non-corrugated packing. In example implementations, one or more of the packing sections 106 includes cross-fluted, parallel plate packing.

[00144] The gas-liquid contactor 100 can include other configurations of the one or more packing section(s) 106 in addition to, or separate from, the packing sections 106 described above. Non-limiting examples of other types of packing, fill, and gas-sorbent interfaces include splash fill, film fill, random packing, mesh, panels, etc. The packing section(s) 106 can include corrugated sheets arranged in a crisscrossing relationship to create flow channels for the vapour phase. The packing section(s) 106 can include any material that fills a space and facilitates the contact between the CO₂-laden air 101 and a sorbent (liquid and/or solid). The packing section(s) 106 can include: a cross flow geometry designed to limit or minimize the pressure drop in the CO₂-laden air 101; can be efficiently wetted by intermittent liquid flows; and, has a liquid hold up enabling intermittent operation with long time durations between wetting.

[00145] The structured packings 116 can be arranged to form packing sections 106 of any desired shape or configuration. For example, and referring to FIG. 1A, the structured packings 116 are arranged such that each packing section 106 A, 106B includes at least one arrangement 118 of the structured packings 116. In FIG. 1 A, each packing section 106A, 106B includes two arrangements 118 of the structured packing 116 - an upper arrangement 118U and a lower arrangement 118L. The structured packings 116 of each arrangement 118 can be arranged adjacent to each other in the direction of one or more of the packing depth 106D, the packing LTD 106L, and the direction perpendicular to both of the packing depth 106D and the packing LTD 106L. All the structured packings 116 of each upper arrangement 118U are positioned above all the structured packings 116 of each lower arrangement 118L. Each arrangement 118 can be considered a “slab” of packing. Other configurations of each arrangement 118, and of the positioning of the arrangements 118 of each packing section 106, are possible. The packing sections 106A, 106B of FIG. 1A are thus vertically sectioned, and include one or more arrangements 118 of structured packings 116 positioned one above another. Attorney Docket No.: 30285-0053W01

[00146] In the example implementation of the packing sections 106 of FIG. 1A, each packing section 106A, 106B has a respective packing section height that is substantially equal to a height of the inlets 1031. Providing the packing sections 106 with substantially the same height as the height of the inlet 1031 can help to prevent or reduce the ability of the CCh-laden air 101 to bypass the packing sections 106 (e.g., flow around the packing sections 106), thereby helping to ensure that the greatest possible volume of CCh-laden air 101 is treated by the packing sections 106. By “substantially equal” or “substantially the same,” it is understood that the heights are approximately equal in value, with any differences being minimal compared to the overall height dimension, where said differences can result from manufacturing tolerances, packing installation requirements, and/or adjustments in dimensions to allow for seals, baffles or other features. Other configurations for the packing sections 106 are possible. For example, in another implementation, the heights of the packing sections 106 A, 106B are less than the height of the inlet 1031, and any gaps between the packing sections 106A, 106B and the housing 102 are sealed using suitable techniques.

[00147] Referring to FIG. 1 A, the gas-liquid contactor 100 has, includes components of, or is functionally linked to, a liquid distribution system 120. The liquid distribution system 120 operates to move, collect and distribute the CO2 capture solution 114 and/or the CCh-laden capture solution 111. At least some of the features of the liquid distribution system 120 are supported by the housing 102 and/or structural members 115. In the example implementation of FIG. 1 A, the support is such that components of the liquid distribution system 120 are structurally supported by the housing 102 and/or by structural members 115, so that loads generated by these components are supported. Some or all of the features of the liquid distribution system 120 can be part of the gas-liquid contactor 100, or part of a DAC system (such as DAC system 1200, 1300, 1400 of FIGS. 11-14 and 18).

[00148] Referring to FIG. 1 A, the liquid distribution system 120 includes one or more liquid collection devices 109. Each liquid collection device 109 is configured to receive one or both of the CO2 capture solution 114 and the CCh-laden capture solution 111 and to hold a volume thereof temporarily or for a longer duration, thereby serving as a source of the CO2 capture solution 114 and/or of the CCh-laden capture solution 111. Each liquid collection device 109 can have any configuration or be made of any material suitable to achieve the function ascribed to it in the present description. For example, one or more of the liquid collection devices 109 can be open-topped, or partially or fully covered. In FIG. 1A, one or more of the liquid collection devices 109 include, or are in the form of, basins. Other configurations of the liquid collection device 109 are possible, such as a reservoir, a bed, a Attorney Docket No.: 30285-0053W01 sheet, a collection pan, a culvert, a container, a receptacle, a network of pressurized pipes with openings or spray nozzles, or any other device capable of retaining liquid.

[00149] The liquid collection devices 109 of the liquid distribution system 120 include one or more top basins 104 and one or more lower liquid collectors 112. The top basins 104 are supported by the housing 102 and/or by the structural members 115. In example implementations, the top basins 104 are formed from portions of the housing 102. The top basins 104 are configured to at least partially enclose or store the CO2 capture solution 114. Referring to FIG. 1 A, the top basins 104 are each positioned at least partially above the packing sections 106. Referring to FIG. 1A, the top basins 104 are positioned above the inlets 1031. Referring to FIG. 1A, the top basins 104 are positioned beneath the upper plenum portion 108U. Part of the plenum 108 (e.g., the upper plenum portion 108U) thus extends beyond or above the top basins 104. When stored (at least transiently) within the top basins 104, the CO2 capture solution 114 is positioned to be circulated (e.g., through pumping, gravity flow or both) predominantly vertically downward, through each of the packing sections 106 A, 106B at the same time, and ultimately into the one or more lower liquid collectors 112. As the CO2 capture solution 114 flows through the packing sections 106, the CCh-laden air 101 is flowed through the packing sections 106 to contact the CO2 capture solution 114, then through the plenum 108, and ultimately to an ambient environment as the CCh-lean gas 105.

[00150] A process stream is formed by contacting the CCh-laden air 101 and the liquid CO2 capture solution 114, where the process stream is or includes the CCh-laden capture solution 111 having CO2 absorbed from the CCh-laden air 101 by the CO2 capture solution 114. The top basins 104 can each have any suitable form or feature for distributing the CO2 capture solution 114 over the packing sections 106. In the example implementation of the gasliquid contactor 100 of FIG. 1A, the liquid collection devices 109 include two top basins 104. Each top basin 104 is positioned above one of the packing sections 106A, 106B to distribute the CO2 capture solution 114 to the respective packing section 106A, 106B. The top basins 104 of FIG. 1A are fluidly isolated from one another (e.g., no fluid communication between the two top basins 104). Other configurations and numbers of the top basins 104 are possible. Other configurations for the distribution of the CO2 capture solution 114 over the packing sections 106 are possible. In one such possible configuration, the one or more of the liquid collection devices 109 include, or are in the form of, a network of pressurized pipes with openings or spray nozzles which distribute the CO2 capture solution 114 over the uppermost portions of the packing sections 106. Attorney Docket No.: 30285-0053W01

[00151] Referring to FIG. 1 A, the one or more one or more lower liquid collectors 112 are positioned at the bottom of the gas-liquid contactor 100 opposite the top basins 104. As can be seen in FIG. 1A, the lower liquid collector(s) 112 are positioned below the packing sections 106. The lower liquid collector(s) 112 act as a collector for the process stream (e.g., the CCh-laden capture solution 111). The CCh-laden capture solution 111 including absorbed CO2, as well as unreacted CO2 capture solution 114, collects in the lower liquid collector(s) 112, and can then be pumped or otherwise moved out of the lower liquid collector(s) 112 for further processing. For example, at least a portion of the liquids collected in the lower liquid collector(s) 112 can be processed and then pumped for redistribution over the packing sections 106 for use in CO2 capture. In another possible implementation, some or all of the liquids collected in the lower liquid collector(s) 112 is pumped to the top basins 104 without being processed, for redistribution over the packing sections 106 for CO2 capture.

[00152] In another possible implementation, some or all of the liquids collected in the lower liquid collector(s) 112 are pumped to components of a DAC system (such as DAC system 1200, 1300, 1400 of FIGS. 11-14 and 18) for further processing, as described in greater detail below. The lower liquid collector(s) 112 can be compatible with a containment structure and prevent loss of various CO2 capture solutions 114, some of which might have corrosive, caustic or high pH properties. In some aspects, the lower liquid collector(s) 112 can be lined or coated with one or more materials that are resistant to caustic induced corrosion or degradation. In example implementations of the gas-liquid contactor 100, components can be kept out of the lower liquid collector(s) 112 holding the CO2 capture solution 114. Additionally, the gas-liquid contactor 100 can be designed to keep most or all the structural components out of the wettable area of the gas-liquid contactor 100, e.g., any portion of the gas-liquid contactor 100 that is in contact with the CO2 capture solution 114. Examples of wettable areas of the gas-liquid contactor 100 includes components supporting the packing sections 106. One or both of the top basin 104 and the lower liquid collector(s) 112 can include liquid-manipulation componentry such as weirs, valves, piping, manifolds, and spray nozzles.

[00153] In example implementations, and referring to FIG. 1 A, the lower liquid collector 112 includes, or is the form of, a bottom basin 110. The bottom basin 110 includes a floor 110F. The floor 110F can define a straight plane or a curved plane, and is positioned such that process streams (e.g., the CCh-laden capture solution 111 and/or the CO2 capture solution 114) flow off the packing sections 106 and onto the floor 110F. The bottom basin 110 includes multiple walls HOW, which have an upright (e.g., vertical) orientation and extend upwardly from the floor 110F. In example implementations, each of the walls HOW is perpendicular to Attorney Docket No.: 30285-0053W01 the floor 110F. The floor 110F and the walls HOW collectively define the containment volume for the bottom basin 110. During operation of the gas-liquid contactor 100, the process streams accumulate in the bottom basin 110 and can reach a design depth, which is a maximum height of the accumulated liquid measured from the floor HOF. The design depth may be selected based on numerous factors, non-limiting examples of which include anticipated changes in volume caused by rain, anticipated changes in volume caused by shutting down the gas-liquid contactor 100, and a margin for accommodating surge events. The design depth can also be selected to maintain minimum flow from the bottom basin 110. In implementations where the capture solution 114 is recirculated from the bottom basin 110, the design depth can also be selected to maintain a selected ratio of capture solution 114 in the system. Referring to FIG. 1 A, the height of the walls HOW, as measured from the floor 110F, is greater than the design depth.

[00154] The floor 11 OF includes portions which are positioned beneath each of the packing sections 106A, 106B. For example, and referring to FIG. 1A, the bottom basin 110 includes a first basin section 110A and a second basin section 110B that is spaced apart from the first basin section 110A along a direction that is horizontal, or parallel to the ATD in FIG. 1 A. The floor 110F of the first basin section 110A is positioned beneath the packing section 106 A so that the first basin section 110A collects the process streams flowing off the packing section 106A. The floor 110F of the second basin section 110B is positioned beneath the packing section 106B so that the second basin section 110B collects the process streams flowing off the packing section 106B. The first basin section 110A and the packing section 106A are components of one of the cells of the dual-cell, cross-flow gas-liquid contactor 100 of FIG. 1 A, while the second basin section 110B and the packing section 106B are components of the other cell of the dual-cell, cross-flow gas-liquid contactor 100 of FIG. 1A. The packing section 106A, 106B of each cell of the gas-liquid contactor 100 of FIG. 1A has a footprint, defined as the area underneath each packing section 106A, 106B. The area of the footprint is calculated by multiplying a first dimension parallel to the packing depth 106D, with a second dimension parallel to a direction that is perpendicular to both the packing depth 106D and to the packing LTD 106L. In example implementations, and referring to FIG. 1 A, the area defined by the floor 110F of each of the first and second basin sections 110A, 110B is equal to or greater than the footprint of each packing section 106 A, 106B, such that the floor 110F of the bottom basin 110 matches or extends beyond the footprint of the packing sections 106 A, 106B. [00155] Referring to FIGS. 1 and 2, the first and second basin sections 110A, 110B are in fluid communication with each other, such that the process streams are free to flow from the Attorney Docket No.: 30285-0053W01 first basin section 110A to the second basin section HOB, from the second basin section HOB to the first basin section 110A, or between the first and second basin sections 110A, 110B. The flow can result from the effects of gravity, because of imparted pressure to the liquid in either basin section 110A, 11 OB, or both. The fluid communication between the first and second basin sections 110A, 110B can take different forms. For example, and referring to FIG. 2, a conduit 1 IOC can extend directly between the first and second basin sections 110A, 110B. The conduit 1 IOC can include, or take the form of, an above ground or underground pipe extending directly between the first and second basin sections 110A, 110B. In another example, both the first and second basin sections 110A, 11 OB drain to a common manifold or vessel, in which the process streams collect and are flowed for subsequent use or treatment, as disclosed herein. [00156] Referring to FIGS. 1 and 2, some or all of the floor 110F is spaced apart from the plenum 108. Some or all of the floor 11 OF is misaligned with the plenum 108. For example, and referring to FIG. 1 A, all of the floor 110F is offset horizontally from the plenum 108, where the horizontal dimension in FIG. 1A is parallel to the packing depth 106D. Referring to FIG. 2, all the portions of the floor 110F and all of the plenum 108 are provided with positions along an axis 11 OX that is parallel to the packing depth 106D and that starts at a common datum 110D. The positions of any portion of the floor 110F along the axis 110X are different from the positions of any part of the plenum 108 along the axis. Referring to FIG. 1A, there is no vertical overlap between the floor 110F and the plenum 108. Referring to FIG. 1A, the floor 110F is vertically unobstructed by the plenum 108. Referring to FIG. 1A, no portion of the plenum 108 vertically overlaps the floor 110F. Referring to FIG. 1A, the floor 110F is not underneath the plenum 108. Referring to FIG. 1A, the floor 110F, and the process streams accumulated in the bottom basin 110, are not underneath the plenum 108.

[00157] By positioning the floor 110F relative to the plenum 108 in this manner, the interior 113 of the gas-liquid contactor 100 becomes more easily accessible to vehicles, equipment or personnel which can enter the plenum 108 unimpeded by portions of the bottom basin 110. This improved access to the interior 113 of the gas-liquid contactor 100 can help with maintenance, repair or replacement of componentry in the interior 113, such as the drift eliminator(s) 117, the structured packings 116 bordering the plenum 108, the fan stack 107 and the fan 121. By positioning the floor 110F relative to the plenum 108 in this manner, it becomes unnecessary to build out the bottom basin 110 under the plenum 108, thereby saving on material and labour costs associated with constructing the bottom basin 110. By positioning the floor 110F relative to the plenum 108 in this manner and preventing process streams from accumulating under the plenum 108, it can be possible to service components in the interior Attorney Docket No.: 30285-0053W01

113 of the gas-liquid contactor 100 once it has been deactivated even while the process streams continue to drain off the packing sections 106A, 106B, thereby providing quicker turnaround during servicing.

[00158] Referring to FIG. 2, a middle area 110M is defined beneath the plenum 108 and between the first and second basin sections 110A, HOB. The middle area HOM has a rectangular shape. The middle area 110M is delimited partially by the walls 110W of the first and second basin sections 110A, 110B that are adjacent to the plenum 108. In example implementations, the middle area 110M is defined by the ground. In example implementations, and referring to FIG. 2, the middle area 110M is defined by a substrate 110S placed over the ground or defining part of the ground. The substrate 110S can be textured, shaped, sloped or otherwise configured to collect liquid (such as rain or drift from the packing section 106), and to transfer such liquid elsewhere. For example, in example implementations, the substrate 110S is composed of gravel laid over a ground liner and sloped toward a drain 11 OR that is fluid communication with one or both of the first and second basin sections 110A, 110B. A height of the substrate 110S is less than a height of the walls HOW, where all heights are measured vertically from a common reference. The first and second basin sections 110A, 110B have a rectangular shape in FIG. 2. Other shapes for the first and second basin sections 110A, 110B are possible.

[00159] The floor 11 OF of the bottom basin 110 can be positioned relative to at grade 500. The grade 500 in such implementations refers to the finished or existing ground level at a specific point, such as adjacent to the gas-liquid contactor 100. Different configurations are possible. For example, in one such configuration, the floor 110F is at, or slightly above, grade 500, such that the bottom basin 110 rests on the ground. In another possible configuration, and referring to FIG. 1 A, the floor 110F is positioned below grade 500 such that the bottom basin 110 is substantially or entirely below ground level. In yet another possible configuration, the floor 110F is positioned above grade 500 such that the bottom basin 110 is positioned above the ground and vertically spaced apart therefrom.

[00160] Other configurations are possible for the lower liquid collector 112 and are described in greater detail below. For example, the lower liquid collector 112 includes, or is the form of, one or more open-topped pipe(s) positioned underneath the packing section 106 (e.g., such as an open-topped pipe positioned underneath each of the packing sections 106A, 106B) and offset from the plenum 108. The floor 110F and/or walls 110W of the one or more open-topped pipe(s) are curved. Attorney Docket No.: 30285-0053W01

[00161] Referring to FIG. 1 A, in example implementations, the gas-liquid contactor 100 includes vertically sectioned packing sections 106 with redistribution of the CO2 capture solution 114 between the vertically-spaced apart packing. For example, and referring to FIG. 1 A, the liquid collection devices 109 of the liquid distribution system 120 include one or more redistribution basins 119. The one or more redistribution basins 119 are each positioned in a redistribution spacing that is defined between the upper and lower arrangements 118U, 118L of each packing section 106A, 106B. The redistribution spacing is a vertically-extending gap defined between the upper and lower arrangements 118U, 118L of each packing section 106 A, 106B. Each packing section 106A, 106B includes a redistribution basin 119, which is positioned in the redistribution spacing of that packing section 106A, 106B. Thus, in the configuration of packing sections 106A, 106B of FIG. 1A, each redistribution basin 119 divides each packing section 106 A, 106B into at least a top section (e.g., the upper arrangement 118U of structured packings 116) and a bottom section (e.g., the lower arrangement 118L of structured packings 116). Each redistribution basin 119 is located vertically between the one or more top basins 104 and the bottom basin 110.

[00162] During operation of the gas-liquid contactor 100, a process stream including the CCh-laden capture solution 111 including absorbed CO2 as well as unreacted CO2 capture solution 114 flows from each upper arrangement 118U of structured packings 116 and collects in each redistribution basin 119. When stored (at least transiently) within the redistribution basins 119, the process stream is positioned to be redistributed (e.g., through pumping, gravity flow or both) downwards, through the remaining structured packings 116 of the lower arrangement 118L and eventually into the bottom basin 110. In example implementations, the process stream is pumped into the redistribution basins 119 from the bottom basin 110. The redistribution basins 119 can each have any suitable form or feature for redistributing the process stream over the structured packings 116 of the of the lower arrangement 118L. Nonlimiting examples of features of the redistribution basins 119 include basin walls, redistribution apertures, and redistribution nozzles. Thus, in the gas-liquid contactor 100, there can be a collector/distributor system between vertical sections of packing that collects fluid flowing from above and redistributes it evenly to the packing below. The description and one, some, or all of the advantages, and functions of features of the top basins 104 and of the bottom basin 110 apply mutatis mutandis to the redistribution basins 119.

[00163] In example implementations, to mitigate or eliminate air bypass through the redistribution basins 119, the redistribution basins 119 can comprise a plurality of vertical baffles. Each of the plurality of vertical baffles can extend from the structural member 115 Attorney Docket No.: 30285-0053W01 immediately above the redistribution basin 119 towards a liquid surface of the liquid held within the redistribution basin 119. Each of the plurality of vertical baffles can be spaced apart equidistantly or at varying distances, along the ATD 106D. The plurality of vertical baffles can prevent the CO2 laden air 101 from bypassing the structured packings 116 by flowing through the redistributions basins 119, such that the flow of the CO2 laden air 101 is directed, or restricted, to the packing sections 106. In particular, each of the plurality of vertical baffles can redirect CO2 laden air 101 air back to the structured packings 116.

[00164] Componentry or structure in or near the redistributions basins 119 can be configured to mitigate or eliminate air bypass through the redistribution basins 119. For example, and referring to FIG. 1A, a bottom surface of the upper arrangement 118U can comprise a plurality of baffles to redirect air back to the structured packing 116 in the upper arrangement 118U.

[00165] In example implementations of redistribution of the CO2 capture solution 114 between the vertically-spaced apart packing, the packing sections 106 themselves include redistribution features. The redistribution features can be part of redistribution packing that is different from the structured packings 116. The redistribution packing can have a vertical extent and be positioned between arrangements 118U, 118L of structured packings 116, for example mid-way up the packing LTD 106L. Alternatively, the redistribution packing can include multiple redistribution packing portions alternating with arrangements 118U, 118L of structured packings 116. In other example implementations of redistribution, the structured packings 116 or a portion of the structured packings 116 can themselves include material or features to flow the CO2 capture solution 114 to lower portions of the packing sections 106. The redistribution features promote redistribution of the CO2 capture solution 114 to lower portions of the packing sections 106. In example implementations of the gas-liquid contactor 100, the gas-liquid contactor 100 does not include vertically-sectioned packing or redistribution.

[00166] Referring to FIG. 1A, the CO2 capture solution 114 flows over the packing sections 106 in a direction that is substantially perpendicular or transverse to the average direction along which the CCh-laden air 101 circulates through the packing sections 106, also known as a “cross flow” configuration. In another possible implementation, the CO2 capture solution 114 flows over the packing sections 106 in a direction that is opposite to the average direction along which the CCh-laden air 101 circulates through the packing sections 106, also known as a “counter flow” configuration. In another possible implementation, the CO2 capture solution 114 flows over the packing sections 106 in a direction that is parallel with the direction Attorney Docket No.: 30285-0053W01 along which the CCh-laden air 101 circulates through the packing sections 106, also known as a “co-current flow” configuration. In another possible configuration, the CO2 capture solution 114 flows over the packing sections 106 according to a configuration that is a combination of one or more of cross flow, counter flow and co-current flow configurations.

[00167] The gas-liquid contactor 100 can include supports positioned within the packing sections 106 between the top basins 104 and bottom basin 110. For example, the packing sections 106 can include additional support, such as one or more structural members 115, for a specific portion of the packing sections 106, such as for an upper portion of the packing sections 106, so that the loads (e.g., the weight of the portion of structured packings 116 when dry plus the weight of the liquid hold up of the CO2 capture solution 114 on the portion of the structured packings 116) do not bear upon another portion of the packing sections 106 (e.g., a bottom portion of the packing sections 106). In example implementations, the packing sections 106 do not include the support. In example implementations, at least one structural support can be positioned between the structured packings 116 of the packing sections 106.

[00168] The liquid distribution system 120 can include any suitable componentry, such as piping, weir(s), pump(s), valve(s), manifold(s), etc., fluidly coupled in any suitable arrangement, to achieve the functionality ascribed to the liquid distribution system 120 herein. One non-limiting example of such componentry is one or more pump(s) 122, an example of which is shown in FIG. 1 A. The pumps 122 function to move liquids under pressure, such as the CO2 capture solution 114 and/or the CO2-laden capture solution 111, from their source to where they are used or processed. Some non-limiting examples of possible functions of the pumps 122 include moving the CO2 capture solution 114 to the top basins 104, moving the process streams from the bottom basin 110 to the redistribution basins 119, moving the CO2 capture solution 114 and/or the CCh-laden capture solution 111 from the bottom basin 110 to the top basins 104 for redistribution over the packing sections 106, moving the CO2 capture solution 114 and/or the CCh-laden capture solution 111 from the bottom basin 110 to components of the DAC system 1200, 1300, 1400, 1500 for further processing, and any combination of the preceding flows. The pumps 122 can thus be used to move liquid to, from and within the gas-liquid contactor 100.

[00169] A control system (e.g., control system 999 shown in FIG. 1A) can be used to control the flow of fluid by the pumps 122 of the liquid distribution system 120. For example, a control system can be used to control the pumps 122 in order to pump the CO2 capture solution 114 from the bottom basin 110 to the top basins 104. The pumps 122 can also be Attorney Docket No.: 30285-0053W01 controlled such that a constant velocity of flow is provided to the liquid distribution system 120 regardless of changes of liquid flow throughout the gas-liquid contactor 100.

[00170] The pumps 122 can help to distribute the CO2 capture solution 114 over the packing sections 106 at relatively low liquid flow rates, which can help to reduce costs associated with pumping or moving the CO2 capture solution 114. Further, low liquid flow rates of the CO2 capture solution 114 over the packing sections 106 can result in a lower pressure drop of the CCh-laden air 101 as it flows through the packing sections 106, which reduces the energy requirements of the device used for moving the CCh-laden air 101 across the packing sections 106 (e.g., a fan 121 described below). The pumps 122 can be configured to generate intermittent or pulsed flow of the CO2 capture solution 114 over the packing sections 106, which can allow for intermittent wetting of the packing sections 106 using relatively low liquid flows. The CO2 capture solution 114 sprayed, flowed, or otherwise distributed over the packing sections 106 is collected in the bottom basin 110 and can then be moved by the pumps 122 back to the top basin 104, or sent elsewhere for processing.

[00171] In example implementations, and referring to FIG. 1 A, the one or more pump(s) 122 of the liquid distribution system are operable to flow the CO2 capture solution 114 over each packing section 106 at a liquid loading rate ranging from 0.5 L/m²s to 10 L/m²s. In example implementations, the liquid loading rate is between 2 L/m²s and 6 L/m²s. The units L/m²s of the liquid loading rate refer to a given volume of the CO2 capture solution 114 covering a given area of the packing section 106, each second. The given area of the packing section 106 can refer to a plane area of a top of the packing section 106, such as the area of the packing section 106 underneath the top basin 104 (e.g., looking down on the top part of the packing section 106 from the top basin 104). When determined using the plane area, a liquid loading rate of 2 L/m²s means that the pump(s) 122 is configured to flow the CO2 capture solution 114 over each packing section 106 such that every second each square meter of the plane area of the packing section 106 receives 2 L of the CO2 capture solution 114. The given area of the liquid loading rate may not refer to the area of a surface of the structured packing 116. The liquid loading rate can refer to, or be reflective of, an initial flow condition where the CO2 capture solution 114 is applied to the top of the packing section 106. The liquid loading rate may not reflect subsequent flow conditions present lower down the packing section 106.

[00172] The liquid process streams in the gas-liquid contactor 100, as well as process streams within any processes with which the gas-liquid contactor 100 is fluidly coupled, can be flowed using one or more flow control systems (e.g., control system 999). A flow control system can include one or more flow pumps (including or in addition to the pumps 122), fans, Attorney Docket No.: 30285-0053W01 blowers, or solids conveyors to move the process streams, one or more flow pipes through which the process streams are flowed and one or more valves to regulate the flow of streams through the pipes. Each of the configurations described herein can include at least one variable frequency drive (VFD) coupled to a respective pump that is capable of controlling at least one liquid flow rate. In example implementations, liquid flow rates are controlled by at least one flow control valve.

[00173] In some embodiments, a flow control system can be operated manually. For example, an operator can set a flow rate for each pump or transfer device and set valve open or closed positions to regulate the flow of the process streams through the pipes in the flow control system. Once the operator has set the flow rates and the valve open or closed positions for all flow control systems distributed across the system, the flow control system can flow the streams under constant flow conditions, for example, constant volumetric rate or other flow conditions. To change the flow conditions, the operator can manually operate the flow control system, for example, by changing the pump flow rate or the valve open or closed position.

[00174] In some embodiments, a flow control system can be operated automatically. For example, the flow control system can be connected to a computer or control system (e.g., control system 999) to operate the flow control system. The control system can include a computer-readable medium storing instructions (such as flow control instructions and other instructions) executable by one or more processors to perform operations (such as flow control operations). An operator can set the flow rates and the valve open or closed positions for all flow control systems distributed across the facility using the control system. In such embodiments, the operator can manually change the flow conditions by providing inputs through the control system. Also, in such embodiments, the control system can automatically (that is, without manual intervention) control one or more of the flow control systems, for example, using feedback systems connected to the control system. For example, a sensor (such as a pressure sensor, temperature sensor or other sensor) can be connected to a pipe through which a process stream flows. The sensor can monitor and provide a flow condition (such as a pressure, temperature, or other flow condition) of the process stream to the control system. In response to the flow condition exceeding a threshold (such as a threshold pressure value, a threshold temperature value, or other threshold value), the control system can automatically perform operations. For example, if the pressure or temperature in the pipe exceeds the threshold pressure value or the threshold temperature value, respectively, the control system can provide a signal to the pump to decrease a flow rate, a signal to open a valve to relieve the pressure, a signal to shut down process stream flow, or other signals. Attorney Docket No.: 30285-0053W01

[00175] The gas-liquid contactor 100 has a gas-circulating device which functions to move gas flows into and out of the gas-liquid contactor 100. In the implementation of the gasliquid contactor of FIG. 1A, the gas-circulating device of the gas-liquid contactor 100 is a fan 121. The fan 121 functions to flow gases like ambient air, such that the CCh-laden air 101 is caused by the fan 121 to flow into the gas-liquid contactor 100, and such that the CCh-lean gas 105 is caused by the fan 121 to be discharged from the gas-liquid contactor 100. The fan 121 thus functions to circulate the CCh-laden air 101 and the CCh-lean gas 105 in the manner described herein. Referring to FIG. 1A, the fan 121 is rotatable about a fan axis defined by a fan shaft. In the implementation of the fan 121 depicted in FIG. 1 A, the fan axis has an upright or vertical orientation. Other orientations for the shaft and for the fan axis are possible, as described in greater detail below. Referring to FIG. 1 A, the fan 121 is positioned upstream of the end of the fan stack 107 that defines the outlet 1030 relative to a flow direction of the CO2- lean gas 105. The fan 121 functions to induce a flow of the CO2-lean gas 105 through the outlet 1030. In another possible configuration, the fan 121 is positioned elsewhere between the vertically-opposite ends of the fan stack 107 and upstream of the outlet 1030, such that the fan 121 flows the CO2-lean gas 105 through the outlet 1030. Referring to FIG. 1A, the fan 121 is positioned downstream of, and above, the upper plenum portion 108U, relative to a flow direction of the CO2-lean gas 105. Rotation of the fan 121 about the fan axis causes gases to flow into the inlets 1031, through the first packing section 106A and the second packing section 106B simultaneously along predominantly horizontal, and opposite, flow directions, and through the gas-liquid contactor 100. For example, in the implementation of the gas-liquid contactor of FIG. 1 A, rotation of the fan 121 causes the CCh-laden air 101 to be drawn into the gas-liquid contactor 100 and causes the CCh-lean gas 105 to be discharged from the gas-liquid contactor 100. The fan 121 can cause the CCh-laden air 101 to enter the packing sections 106 at airspeeds below 5 m/s. The fan 121 can cause the CCh-laden air 101 to enter the packing sections 106 at airspeeds between 0.1 m/s and 5 m/s.

[00176] Other configurations of the gas-liquid contactor 100 are possible, some of which are now described in greater detail.

[00177] In one such possible configuration, and referring to FIG. 3A, the gas-liquid contactor 100 A can have an upright body and an air inlet 203 along a bottom portion through which the CCh-laden air 101 is admitted into the gas-liquid contactor 100A. The fan 221 rotates to draw the C Ch-laden air 101 through the inlet 203 in an upward direction to contact the packing section 206. In the configuration of FIG. 3 A, the gas-liquid contactor 100A has only one packing section 206 and can therefore be referred to as a “single cell” gas-liquid contactor Attorney Docket No.: 30285-0053W01

IOOA. The CO2 capture solution 114 circulates downwards by, for example, gravity flow, uniform or laminar flow, etc., within the packing 206 and eventually flows into one or more bottom basins 210. As the CO2 capture solution 114 circulates through and over the packing 206, the CCh-laden air 101 is flowing (e.g., by action of the fan 221) upwardly through the packing 206 to contact the CO2 capture solution 114. Thus, the flow of the CO2 capture solution 114 through the packing 206 in FIG. 3 A is counter-current (or counterflow) to the flow of the CCh-laden air 101 through the packing 206. The packing liquid travel dimension along which the CO2 capture solution 114 flows through the packing 206 is defined along the vertical direction and is the same as the packing depth along which the CCh-laden air 101 flows upwardly through the packing 206. A portion of the CO2 within the CCh-laden air 101 is transferred to (e.g., absorbed by) the CO2 capture solution 114, and the fan 221 moves the CO2 lean gas 105 out of the gas-liquid contactor 100 A to an ambient environment. The CCh-laden capture solution 111 and the CO2 capture solution 114 flow into the at least one bottom basin 210.

[00178] Referring to FIG. 3B, another possible configuration of a gas-liquid contactor 100B has an upright body and an inlet 303 along an upright side portion through which the CCh-laden air 101 is admitted into the gas-liquid contactor 100B. The fan 321 rotates about a horizontal fan axis to draw the CCh-laden air 101 through the inlet 303 in a substantially horizontal direction to contact the packing section 306. In another possible configuration where the CCh-laden air 101 flows through the inlet 303 in a substantially horizontal direction, the fan 321 is positioned downstream of the packing section 306 and rotates about a vertical fan axis. In another possible implementation of the gas-liquid contactor 100B, the fan 321 is upstream of the packing section 306 relative to the flow direction of the CCh-laden air 101. In such an implementation, the gas-liquid contactor 100B employs forced draft in which the fan 321 rotates about a horizontal fan axis to “push” the CCh-laden air 101 through the inlet 303 in a substantially horizontal direction to contact the packing section 306.

[00179] In the configuration of FIG. 3B, the gas-liquid contactor 100B has only one section of packing 306 and can therefore be referred to as a “single cell” gas-liquid contactor

IOOB. The CO2 capture solution 114 circulates downwards by, for example, gravity flow, uniform or laminar flow, etc., within the packing 306 and eventually flows into one or more bottom basins 310. As the CO2 capture solution 114 circulates through the packing 306, the CCh-laden air 101 is flowing (e.g., by action of the fan 321) substantially horizontally through the packing 306 to thereby contact the CO2 capture solution 114. Thus, the flow of CO2 capture solution 114 through the packing 306 in FIG. 3B is substantially perpendicular to the flow of Attorney Docket No.: 30285-0053W01 the CC -laden air 101 through the packing 306. Such a configuration of the flows can be referred to as a “cross flow” configuration. The packing liquid travel dimension along which the CO2 capture solution 114 flows through the packing 306 is defined along the vertical direction and is perpendicular to the packing depth along which the CCh-laden air 101 flows horizontally through the packing 306. A portion of the CO2 within the CCh-laden air 101 is transferred to the CO2 capture solution 114, and the fan 321 moves the CCh-lean gas 105 out of the gas-liquid contactor 100B to an ambient environment. The CCh-laden capture solution 111 and the CO2 capture solution 114 flow into the at least one bottom basin 310.

[00180] Referring to FIG. 3C, another possible configuration of a gas-liquid contactor 100C has an upright body and an air inlet 403 along a top portion through which the CCh-laden air 101 is admitted into the gas-liquid contactor 100C. The fan 421 rotates to push the CCh- laden air 101 into the gas-liquid contactor 100C and contact the packing section 406. In the configuration of FIG. 3C, the gas-liquid contactor 100C has only one packing section 406 and can therefore be referred to as a “single cell” gas-liquid contactor 100C. The CCh capture solution 114 circulates downwards by, for example, gravity flow, uniform or laminar flow, etc., within the packing 406 and eventually flows into one or more bottom basins 410. As the CCh capture solution 114 circulates downward through and over the packing 406, the CCh-laden air 101 (e.g., by action of the fan 421) also flows downward through the packing 406 to contact the CCh capture solution 114. Thus, the flow of the CCh capture solution 114 through the packing 406 in FIG. 3C is co-current to the flow of the CCh-laden air 101 through the packing 406. The packing liquid travel dimension along which the CCh capture solution 114 flows through the packing 406 is defined along the vertical direction and is the same as the packing depth along which the CCh-laden air 101 flows downwardly through the packing 406. At least a portion of the CCh within the CCh-laden air 101 is transferred to (e.g., absorbed by) the CCh capture solution 114, and the fan pushes the CCh lean gas 105 out of the gas-liquid contactor 100C to an ambient environment. The CCh-laden capture solution 111 and the CO2 capture solution 114 flow into the at least one bottom basin 410.

[00181] Other possible configurations of the gas-liquid contactor 100 include a gasliquid contactor 100 which receives the CO2-laden air 101, flows the CO2 capture solution 114 to contact the CO2 in the CO2-laden air 101, releases the CO2-lean gas 105, and allows for the CO2-laden capture solution 111 to be flowed to release CO2 gas and regenerate the CO2 capture solution 114. Such a gas-liquid contactor 100C is represented in FIG. 3D. The gas-liquid contactor 100D can have any suitable configuration of internal and external components. Some non-limiting examples of possible configurations for the gas-liquid contactor 100D include Attorney Docket No.: 30285-0053W01 being a modular unit, being rounded or circular, being a cell of an array or train of gas-liquid contactors 100, 100A, 100B, 100C, 100D, being a cell of a rounded or circular gas-liquid contactor 100, 100 A, 100B, 100C, 100D, and being a component of a heating, ventilation, and air conditioning (HVAC) system.

[00182] The gas-liquid contactor 100 may include, or be fluidly coupled to, devices for managing liquid level in the gas-liquid contactor 100. These devices can include, but are not limited to, evaporators to reduce liquid levels and/or maintain concentrations of the CO2 capture solution 114. These devices can include, but are not limited to, water make-up tanks or sources to manage liquid levels and/or maintain concentrations of the CO2 capture solution 114.

[00183] The DAC system 1200, 1300, 1400, 1500 can include multiple gas-liquid contactors 100, 100A, 100B, 100C, 100D. In example implementations, the DAC system 1200, 1300, 1400, 1500 includes multiple gas-liquid contactors 100, 100A, 100B, 100C, 100D arranged adjacent each other to form an array or a train of gas-liquid contactors 100, 100 A, 100B, 100C, 100D. The DAC system 1200, 1300, 1400, 1500 can include multiple arrays or trains of gas-liquid contactors 100, 100A, 100B, 100C, 100D.

[00184] The description, at least some of the advantages, and the functions of features of the gas-liquid contactor 100 of FIG. 1A that are shown in FIGS. 3 A, 3B, 3C apply mutatis mutandis to the features of the gas-liquid contactor 100A, 100B, 100C, 100D of FIGS. 3A-3D. [00185] Each gas-liquid contactor 100, 100A, 100B, 100C, 100D can be grouped together with one or more other gas-liquid contactors 100, 100A, 100B, 100C, 100D to form one or more wall(s), array(s) or train(s), where each wall, array or train has multiple gas-liquid contactors 100, 100A, 100B, 100C, 100D. For example, and referring to FIG. 4A, multiple gas-liquid contactors 100, 100 A, 100B, 100C, 100D are arranged next to one another to form a contactor wall 1502. The number of gas-liquid contactors 100, 100A, 100B, 100C, 100D composing the contactor wall 1502 may vary (as represented by the ellipsis symbol “[.. .]” in FIG. 4A). The contactor wall 1502 may include a large number of gas-liquid contactors 100,

IOOA, 100B, 100C, 100D for example between 10 and 100 gas-liquid contactors 100, 100A,

IOOB, 100C, 100D. In example implementations, the number of gas-liquid contactors 100, 100A, 100B, 100C, 100D in the contactor wall 1502 is greater than 1,000. The number of gasliquid contactors 100, 100A, 100B, 100C, 100D in the contactor wall 1502 may be determined based on a variety of factors, such as a plume of CCh-lean gas 105 generated by the contactor wall 1502 during operation of the gas-liquid contactors 100, 100A, 100B, 100C, 100D. Attorney Docket No.: 30285-0053W01

[00186] The contactor wall 1502 extends along its own wall axis 1509. The wall axis 1509 extends along a direction that is perpendicular to the packing depth 106D of the gas-liquid contactors 100, 100A, 100B, 100C, 100D and perpendicular to the packing LTD 106L of the gas-liquid contactors 100, 100A, 100B, 100C, 100D. In implementations where the gas-liquid contactors 100, 100 A, 100B, 100C, 100D are positioned (e.g., directly) adjacent each other, and referring to FIG. 4A they may be abutted along a dividing wall 1525 which fluidly separates components of one gas-liquid contactor 100, 100A, 100B, 100C, 100D from an adjacent gas-liquid contactor 100, 100A, 100B, 100C, 100D. The dividing wall 1525 helps to ensure that the CCL-laden air 101 flowing through the air inlet 1031 of a gas-liquid contactor 100, 100 A, 100B, 100C, 100D flows through the packing section(s) 106 of that gas-liquid contactor 100, 100A, 100B, 100C, 100D rather than into an adjacent gas-liquid contactor 100, 100A, 100B, 100C, 100D. The dividing walls 1525 extend in an upright or vertical direction, and along a direction parallel to the packing depth 106D. In example implementations, the vertical extent of one or more of the dividing walls 1525 begins at, or below, the liquid level in the bottom basin 510. This configuration of the dividing walls 1525 can help to minimise or eliminate air bypassing the dividing walls 1525.

[00187] The contactor wall 502, 1502 can be part of the DAC system 1200, 1300, 1400, 1500. Referring to FIG. 4B, each DAC system 1200, 1300, 1400, 1500 can include multiple contactor walls 502, 1502 arranged on a plot of land 1505. Each contactor wall 502, 1502 is spaced apart from another contactor wall 502, 1502. In this disclosure, the terms “train”, “array” and “wall” may be used interchangeably.

[00188] The DAC system 1200, 1300, 1400, 1500 of FIG. 4B is shown with multiple contactor walls 502, 1502 for the purposes of illustration. The DAC system 1200, 1300, 1400, 1500 can alternatively have only one contactor wall 502, 1502. Referring to FIG. 4B, the DAC system 1200, 1300, 1400, 1500 includes a regeneration system 1230, 1330, 1430, such as one or more of those described above, in fluid communication with the contactor walls 502, 1502. The regeneration system 1230, 1330, 1430 functions to regenerate the CCL-rich sorbent (e.g., the CCL-laden capture solution 111) received from the contactor walls 502, 1502, or from other componentry that treats the CCL-laden capture solution 111 from the contactor walls 1502. The regeneration system 1230, 1330, 1430 forms a regenerated sorbent (e.g., the regenerated CO2 capture solution 114) that is conveyed back to the contactor walls 502, 1502. The regeneration system 1230, 1330, 1430 can also function to release CO2 from the CCL-rich sorbent, to produce the CO2 product stream. In example implementations, and referring to FIG. 4B, each contactor wall 502, 1502 has a single or common bottom basin 510. In such implementations, the Attorney Docket No.: 30285-0053W01 common bottom basin 510 can have a cross-sectional shape as described above. In example implementations, the bottom basin 510 of each contactor wall 502, 1502 is in fluid communication with the regeneration system 1230, 1330, 1430. In example implementations, the process streams from the bottom basin 510 of a contactor wall 502, 1502 flows, or is flowed, to the bottom basin 510 of another contactor wall 502, 1502.

[00189] In example implementations, the DAC system 1200 includes componentry to accommodate variations in the level of the CO2 capture solution 114 and the CCh-laden capture solution 111 stored by the gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D. One nonlimiting example of such componentry includes one or more surge tank(s) 1250 or vessel, an example of which is illustrated in FIG. 4B. In example implementations, and referring to FIG. 4B, each contactor wall 502, 1502 is in fluid communication with a single surge tank 1250, such that the lower liquid collector 112 (e.g., the bottom basin 510) of each contactor wall 502, 1502 is in fluid communication with the respective single surge tank 1250. In alternate implementations, an example of which is shown in FIG. 4B, one or more of the surge tank(s) 1250 are in fluid communication with the bottom basins 510 of multiple contactor walls 502, 1502. Each surge tank 1250 is spaced apart from the contactor wall 502, 1502 with which they are in fluid communication. In example implementations where the cross-sectional shape of the bottom basin 510 forms an “H”, “C”, “U”, “M”, “S”, “Z”, etc., the combined volumes of the bottom basin 510 and the surge tank 1250 provide a given contactor wall 502, 1502 with additional or actual surge capacity. This surge capacity can provide enough volume capacity to containing liquid from the gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D of the contactor wall 502, 1502 in the event that one or more of them are shutdown, while also allowing for containing liquids resulting from surge events. Non-limiting examples of surge events include swings in the water balance in the contactor wall 502, 1502 resulting from weather events (e.g., rain), and seasonal variations (e.g., changes in the relative humidity of the CCh-laden air 101). In alternate implementations of the bottom basin 510, as described below, the contactor wall 502, 1502 may not include a surge tank 1250 and may instead include other liquid retention techniques for managing surge events.

[00190] Another example implementation of the contactor wall 502 is provided in FIG.5A. The contactor wall 502 extends along its wall axis 509, which is perpendicular to the packing depth 106D and perpendicular to the packing LTD 106L. The contactor wall 502 has a bottom basin 510. In the example implementation of FIG. 5 A, the contactor wall 502 has a single bottom basin 510. In the example implementation of FIG. 5A, the bottom basin 510 is common to all the gas-liquid contactors 100, 100 A, 100B, 100C, 100D forming the contactor Attorney Docket No.: 30285-0053W01 wall 502. Referring to FIG. 5 A, the bottom basin 510 is positioned beneath the packing sections 106 of all the gas-liquid contactors 100, 100 A, 100B, 100C, 100D forming the contactor wall 502. To better illustrate the features of FIG. 5A and facilitate description thereof, FIG. 5 A shows componentry for only one of the gas-liquid contactors 100, 100 A, 100B, 100C, 100D forming the contactor wall 502. It will be appreciated that the features of the gas-liquid contactor 100, 100 A, 100B, 100C, 100D shown in FIG. 5 A and the description thereof apply mutatis mutandis to all the other gas-liquid contactor 100, 100A, 100B, 100C, 100D not shown in FIG. 5 A.

[00191] The contactor wall 502 includes one or more plenum(s) 508. In some example implementations, and referring to FIG. 5A, the contactor wall 502 includes multiple plenums 508, where each gas-liquid contactor 100, 100A, 100B, 100C, 100D forming the contactor wall 502 has one plenum 508. Each plenum 508 is separated from an adjacent plenum 508 by one or more dividing walls 1525. At least some of the dividing walls 1525 are internal to the contactor wall 502. Each dividing wall 1525 forms a barrier to airflow between the adjacent plenums 508 delimited by that dividing wall 1525, so as to prevent air from flowing between the plenums 508. In the example implementation of FIG. 5 A, the dividing wall 1525 shown is located between two fan stacks 107A, 107B, and forms a barrier to airflow between the adj acent plenums 508 each of which is in fluid communication with a respective one of the fan stacks 107A, 107B. The dividing wall 1525 shown in FIG. 5 A is further from one end of the contactor wall 502 than the fan stack 107A and is closer to the same end of the contactor wall 502 than the fan stack 107B, as measured in a direction parallel to the wall axis 509 (see also the dividing walls 1525 of FIG. 4A). The dividing walls 1525 may allow for multiple gas-liquid contactors 100, 100A, 100B, 100C, 100D of the contactor wall 502 to remain operational if one of the gas-liquid contactors 100, 100A, 100B, 100C, 100D or its fan 121 is deactivated. The dividing wall 1525 of FIG. 5 A is internal to the contactor wall 502, and it will be appreciated that the contactor wall 502 can have externally-applied dividing walls 1525 at opposite longitudinal ends of the contactor wall 502. The plenums 508 are arranged adjacent each other along the length of the contactor wall 502 defined along the wall axis 509. In other implementations, the contactor wall 502 includes a single plenum 508 that is continuous along its length defined parallel to the wall axis 509, such that the contactor wall 502 is free of dividing walls 1525. In other implementations, the contactor wall 502 includes multiple plenums 508 delineated by the dividing walls 1525, where two or more gas-liquid contactors 100, 100 A, 100B, 100C, 100D of the contactor wall 502 share a common plenum 508. In example implementations, the Attorney Docket No.: 30285-0053W01 dividing walls 1525 include doors or closeable openings, to provide access to the interior 113 of adjacent gas-liquid contactors 100, 100A, 100B, 100C, 100D.

[00192] The bottom basin 510 is an elongated body and extends along a collector axis 512. The collector axis 512 is parallel to the wall axis 509. Referring to FIG. 5 A, the floor 510F of the bottom basin 510 is positioned beneath the packing sections 106 of all the gasliquid contactors 100, 100A, 100B, 100C, 100D forming the contactor wall 502. Referring to FIG. 5A, the floor 510F of the bottom basin 510 is positioned beneath all the cells of all the dual-cell gas-liquid contactors 100, 100A, 100B, 100C, 100D forming the contactor wall 502. The floor 510F can define a straight plane or a curved plane, and is positioned such that process streams (e.g., the CCh-laden capture solution 111 and/or the CO2 capture solution 114) flow off the packing sections 106 and onto the floor 510F. The walls 510W of the bottom basin 510 have an upright (e.g., vertical) orientation, and extend upwardly and perpendicularly from the floor 51 OF. During operation of the gas-liquid contactors 100, 100 A, 100B, 100C, 100D forming the contactor wall 502, the process streams accumulate in the bottom basin 510 and can reach a design depth, which is a maximum height of the accumulated liquid measured from the floor 510F. The design depth may be selected based on numerous factors, non-limiting examples of which include anticipated changes in volume caused by rain, anticipated changes in volume caused by shutting down one or more of the gas-liquid contactors 100, 100 A, 100B,

IOOC, 100D and a margin for accommodating surge events. Referring to FIG. 5 A, the height of the walls 510W, as measured from the floor 51 OF, is greater than the design depth.

[00193] The floor 51 OF includes portions which are positioned beneath each of the packing sections 106A, 106B of each of the gas-liquid contactors 100, 100A, 100B, 100C,

IOOD. For example, and referring to FIG. 5A, the bottom basin 510 includes a first basin section 510A (sometimes referred to herein as a “first portion 510A”) and a second basin section 510B (sometimes referred to herein as a “second portion 510B”). The second basin section 510B is spaced apart from the first basin section 510A along a direction that is horizontal in FIG. 5A, or parallel to the packing depth 106D. The first basin section 510A is an elongated body and extends along a first basin section axis 514A, and the second basin section 510B is an elongated body and extends along a second basin section axis 514B. The first and second basin section axes 514A, 514B are parallel. The first and second basin section axes 514A, 514B are parallel to the collector axis 512. The first and second basin section axes 514A, 514B are parallel to the wall axis 509.

[00194] Referring to FIG. 5 A, the floor 51 OF of the first basin section 510A is positioned beneath the packing sections 106A of all the gas-liquid contactors 100, 100A, 100B, 100C, Attorney Docket No.: 30285-0053W01

100D of the contactor wall 502, so that the first basin section 510A collects the process streams flowing off the packing sections 106A. The floor 510F of the second basin section 510B is positioned beneath the packing sections 106B of all the gas-liquid contactors 100, 100A, 100B, 100C, 100D of the contactor wall 502, so that the second basin section 51 OB collects the process streams flowing off the packing sections 106B. The packing sections 106 A, 106B of the gas-liquid contactors 100, 100A, 100B, 100C, 100D have a footprint defined as the area underneath all the packing sections 106 A, 106B. The area of the footprint of a packing section 106A, 106B is calculated by multiplying a first dimension of the respective packing section 106 A, 106B parallel to the packing depth 106D with a second dimension of the respective packing section 106A, 106B parallel to the wall axis 509 or to the collector axis 512. In example implementations, and referring to FIG. 5 A, the area defined by the floor 51 OF of each of the first and second basin sections 510A, 510B is equal or greater than the footprint of all the packing sections 106A, 106B, such that the floor 51 OF of the bottom basin 510 matches or extends beyond the footprint of all the packing sections 106 A, 106B.

[00195] In example implementations, one or more of the structural members 115 of one or more of the gas-liquid contactors 100, 100A, 100B, 100C, 100D is mounted above the floor 510F of the bottom basin 510 of the contactor wall 502. Referring to FIGS. 5A and 5B at least some structural members 115 are mounted to at least some walls 510W of the bottom basin 510. In such example implementations, the walls 510W of the bottom basin 510 are used as structural supports for one or more components of one or more of the gas-liquid contactors 100, 100A, 100B, 100C, 100D. In such example implementations, the bottom basin 510 achieves at least two functions: it allows for collecting and retaining liquids, and it provides structural support. In example implementations, and referring to FIGS. 5 A and 5B, some structural members 115 are mounted to the plenum walls 510WP, and some structural members 115 are mounted to the outer walls 510WO. In such implementations, the structural members 115 can be mounted to the walls 510W of the bottom basin 510 on both the plenum side and on the outer side of the packing sections 106. Referring to FIGS. 5Aand 5B, some structural members 115 are mounted to the end walls 510WE. Referring to FIGS. 5A and 5B, some structural members 115 are mounted to the connection section walls 510WC. The structural members 115 extend upwardly from the walls 510W to other componentry, for example the top basins 104 of the contactor wall 502. The structural members 115 can be mounted to any of the walls 510W of the bottom basin 510, in any combination, for example to support some or all of the static and operational loads of the contactor wall 502 from the bottom basin 510. Attorney Docket No.: 30285-0053W01

[00196] The mounting of the structural members 115 to the walls 510W can take different forms. For example, and referring to FIG. 5B, the walls 510W have upper wall portions 510WU that are parallel to the horizontal. Each upper wall portion 510WU defines the thickness of the corresponding wall 510W. In example implementations, the structural members 115 are mounted onto the upper wall portions 510WU and extend upwardly therefrom. The structural members 115 may be secured to the upper wall portions 510WU using any suitable technique, such as via a flange secured to the upper wall portion 510WU as shown in FIG. 5B In alternate implementations, one or more structural members 115 are secured to the upper wall portions 510WU via a flange, bracket, mount, etc. that extends horizontally outwardly from the upper wall portions 510WU, such that the structural members 115 are positioned above the floor 51 OF of the bottom basin 510. In example implementations, the structural members 115 are mounted to the wall 510W such that the packing section 106 is spaced apart from the wall 510W for load bearing and tolerance purposes. In such implementations, a space created between the packing section 106 and the wall 510W can be filled by air seals or other comparable sealing mechanism.

[00197] In example implementations, and referring to FIG. 5B, one or more structural members 115 are mounted onto lower wall portions 51 OWL. The lower wall portions 51 OWL extend vertically. Each lower wall portion 51 OWL extends from a corresponding upper wall portion 510WU in a direction that is vertically downward. Each lower wall portion 51 OWL extends vertically between a corresponding upper wall portion 510WU and the floor 51 OF of the bottom basin 510. In example implementations, and referring to FIG. 5B, the structural members 115 mounted to the lower wall portions 51 OWL have a base that is above the liquid level 510L of the bottom basin 510. The structural members 115 may be secured to the lower wall portions 510WL using any suitable technique. For example, and referring to FIG. 5B, the structural member 115 is secured to the lower wall portion 51 OWL via a bracket mounted to the lower wall portion 51 OWL with suitable fasteners or with welding, along an inner surface of the lower wall portion 510WL (i.e., a surface facing toward and in fluid contact with the liquid in the bottom basin 510). In other example implementations, the structural member 115 secured to the lower wall portion 510WL is positioned along an outer surface of the lower wall portion 510WL, e.g., a surface facing away from, and not in fluid contact with, the liquid in the bottom basin 510. The structural members 115 can be mounted to either one, or both, of the upper and lower wall portions 510WU, 51 OWL, in any combination, an example of which is shown in FIG. 5B. In example implementations, one or more of the structural member 115 have a horizontal orientation and extend across the bottom basin 510 between opposed walls Attorney Docket No.: 30285-0053W01

510W, such that portions of these structural members are positioned above the floor 51 OF. In example implementations, the structural members 115 and/or their connectors by which they are secured to the walls 510W can be made from, lined, and/or coated with one or more materials that are resistant to caustic induced corrosion or degradation.

[00198] Referring to FIG. 5A, a basin width for each of the first and second basin sections 510A, 51 OB is defined along a direction parallel to the packing depth 106D, and between the inner-facing surface of the plenum wall 510WP and the inner-facing surface of the outer wall 510WO of each of the first and second basin sections 510A, 510B. The basin width is equal to, or greater than, the packing depth 106D. The basin width being equal to, or greater than, the packing depth 106D helps to ensure that liquid flowing off the packing sections 106 falls into the bottom basin 510, rather than onto surfaces outside of the contactor wall 502. The basin width being equal to, or greater than, the packing depth 106D helps to ensure that the packing sections 116 remain within the walls 510W of the bottom basin 510, and above the floor 51 OF. In example implementations, the basin width is a maximum of 10 ft greater than the packing depth 106D. In example implementations, the basin width is a maximum of 5 ft greater than the packing depth 106D. In example implementations, the basin width is between 1-2 ft greater than the packing depth 106D.

[00199] Referring to FIG. 6, the first and second basin sections 510A, 510B are in fluid communication with each other, such that the process streams are free to flow from the first basin section 510A to the second basin section 510B, from the second basin section 510B to the first basin section 510A, or between the first and second basin sections 510A, 510B. The flow can result from the effects of gravity, because of imparted pressure to the liquid in either basin section 510A, 510B, or both. The fluid communication between the first and second basin sections 510A, 510B can take different forms. For example, and referring to FIG. 6, the bottom basin 510 includes one or more connection sections 510C that extend directly between the first and second basin sections 510A, 510B, and allows for liquid flow therebetween. In the example implementation of FIG. 6, the connection section 510C includes or defines part of the floor 51 OF of the bottom basin 510. In the example implementation of FIG. 6, the connection section 510C includes, or is delimited by, the walls 510W of the bottom basin 510 extending upwardly from the floor 510F. In other implementations, the connection section 510C can include, or take the form of, an above ground or underground pipe extending directly between the first and second basin sections 510A, 510B. In another example implementation, the connection section 510C is absent, and both the first and second basin sections 510A, 510B Attorney Docket No.: 30285-0053W01 drain to a common manifold or vessel, in which the process streams collect and are flowed for subsequent use or treatment, as disclosed herein.

[00200] The floor 51 OF of the bottom basin 110 can be positioned relative to at grade 500. The grade 500 in such implementations refers to the finished or existing ground level at a specific point, such as adjacent to the gas-liquid contactor 100. Different configurations are possible. For example, in one such configuration, the floor 510F is at, or slightly above, grade 500, such that the bottom basin 510 rests on the ground. In another possible configuration, and referring to FIG. 6, the floor 510F is positioned below grade 500 such that the bottom basin 510 is substantially or entirely below ground level. Many configurations of the first basin section 510A, second basin section 510B, and connection section 510C are possible. For example, and referring to FIG. 6, the bottom basin 510 includes a single connection section 510C extending between the middle of the length of the first and second basin sections 510A, 510B, where the length is measured along a direction parallel to the collector axis 512. When viewed from above and as shown in FIG. 6, the first basin section 510A, second basin section 510B, and connection section 510C form a bottom basin 510 shaped like the letter “H”. Referring to FIG. 6, a cross-sectional shape of the bottom basin 510 can be defined in a plane that is normal to the vertical, and the cross-sectional shape forms an “H”. Other cross-sectional shapes for the bottom basin 510 are possible, non-limiting examples of which include:

• “C”, “D”, and “V” cross-sectional shapes (formed by one or more basin sections 510A, 510B without a connection section 510C);

• “U” cross-sectional shapes (formed by two basin sections 510A, 510B with a curved connection section 510C);

• “M” and “W” cross-sectional shapes (formed by two basin sections 510A, 510B with two connection sections 510C); and

• “A”, “S”, “Z”, or “N” cross-sectional shapes (formed by two basin sections 510A, 510B with a curved or straight connection section 510C).

[00201] In another example implementation of a cross-sectional shape for the bottom basin 510, the bottom basin 510 includes multiple basin sections 510A, 510B extending parallel to each other, and multiple connection sections 510C extending parallel to each other and perpendicularly to the basin sections 510A, 510B, so as to form the roman numeral “111” or the letters “E” and “B” cross-sectional shapes, for example. In other example implementations, the single connection section 510C extends between other lengthwise positions of the first and second basin sections 510A, 510B. Referring to FIG. 6, the connection section 510C forms a Attorney Docket No.: 30285-0053W01 right angle with the first and second basin sections 510A, 51 OB. In other example implementations, the connection section 5 IOC forms an angle with the first and second basin sections 510A, 51 OB that is greater than 0 and less than 90 degrees. In other example implementations, multiple connection sections 510C extend between the first and second basin sections 510A, 51 OB, and each connection section 510C is spaced apart from another connection section 510C in a direction parallel to the collector axis 512. Referring to FIG. 6, the first and second basin sections 510A, 51 OB are continuous. In other example implementations, the first and second basin sections 510A, 51 OB are discontinuous and interrupted by multiple connection sections 510C.

[00202] The plenum 508 of FIG. 6 is shown as a single, continuous plenum 508 to better illustrate the features of FIG. 6 and facilitate description thereof. It will be appreciated that multiple, discontinuous plenums 508 may be present in FIG. 6, as described above with respect to FIG. 5 A. For clarity, in the description of FIG. 6, the continuous plenum 508 or multiple plenums 508 are described collectively as “the plenum(s) 508”.

[00203] Referring to FIG. 6, each of the first and second basin sections 510 A, 510B have longer sides that extend parallel to the collector axis 512 and have shorter sides that extend from the longer sides perpendicularly to the collector axis 512 and perpendicularly to the LTD 106L. In the example implementation of the bottom basin 510 of FIG. 6, the longer sides of each of the first and second basin sections 510A, 510B include a plenum side 510P that faces and abuts the plenum(s) 508, and an outer side 5100 opposite to the plenum side 51 OP relative to the packing depth 106D. The outer side 5100 faces away from the plenum(s) 508. In the example implementation of the bottom basin 510 of FIG. 6, each of the outer sides 5100 includes, or is defined by, an outer wall 510WO. Each of the plenum sides 510P includes, or is defined by, a plenum wall 510WP. The shorter sides of each of the first and second basin sections 510A, 510B include end walls 510WE that extend between the outer and plenum walls 510WO, 510WP and are perpendicular thereto. Each of the end walls 51 OWE extends along a direction that is perpendicular to the LTD 106L, and perpendicular to the collector axis 512 (and to axes parallel to the collector axis 512, such as the first and second basin sections axes 514A, 514B).

[00204] Referring to FIG. 6, the one or more liquid collection devices 109 includes a sump 516 that is in fluid communication with one or both of the first and second basin sections 510A, 510B. The sump 516 can receive liquids such as the process streams (e.g., the CO2- laden capture solution 111 and/or the CO2 capture solution 114) and/or rainwater from one or more of the first basin section 510A, second basin section 510B, and connection section 510C. Attorney Docket No.: 30285-0053W01

The sump 516 can be a volume or reservoir with a bottom portion that is positioned lower than portions of the bottom basin 510, so as to receive therefrom liquid flowing due to gravity. The sump 516 can include a liquid conveyance device, such as a sump pump, to flow the received liquids for subsequent use or processing. Referring to FIG. 6, the sump 516 is positioned adjacent to the bottom basin 510 along a portion thereof. In the example implementation of the H-shaped bottom basin 510 of FIG. 6, the sump 516 is positioned adjacent to, and in fluid communication with, one of the first and second basin sections 510A, 510B. Referring to FIG. 6, the sump 516 is positioned adjacent to, and in fluid communication with, the second basin section 510B. The sump 516 is positioned along the outer wall 510WO of the second basin section 510B. The sump 516 is positioned along the outer wall 510WO of the second basin section 51 OB at a location thereon that is between the opposed end walls 51 OWE of the second basin section 510B. In the example implementation of FIG. 6, the sump 516 is positioned along one of the “legs” of the H-shaped bottom basin 510 that is parallel to the wall axis 509, between the ends of the “H”. An opening 518 in the outer wall 510WO allows liquids to flow from the second basin section 510B into the sump 516. In example implementations, the floor 510F of the connection section 510C is sloped toward the second basin section 510B, such that process streams flow due to gravity from the first basin section 510A, along the floor 51 OF of the connection section 510C, to the second basin section 510B (and ultimately into the sump 516). In such implementations, the connection section 510C of the bottom basin 510 can be designed for equalizing the liquid level in the first and second basin sections 510A, 510B, and is thus sized accordingly to accommodate numerous flow conditions, such as if all the liquid in the first basin section 510A needs to flow to the second basin section 510B. In other possible implementations, the sump 516 is positioned along one of the walls 510WC of the connection section 510C.

[00205] In example implementations, a slope of the floor 510F of the first basin section 510A is greater than a slope of the floor 51 OF of the second basin section 510B, or vice versa, such that liquid flows from one basin section 510A,510B to another basin section 510A,510B. In other example implementations, the slope of the floor 51 OF of the first and second basin sections 510A, 510B may be the same. In example implementations, a sump slope may be present, where the slump slope is defined to be the slope from the first basin section 510A and/or the second basin section 510B to the sump 516. In example implementations, the sump slope can be a portion of the floor 510F of the first and/or second basin sections 510A, 510B. In other implementations, the sump slope can be an auxiliary structural body extending from the floor 510F of the first and/or second basin sections 510A, 510B. The sump slope can be a Attorney Docket No.: 30285-0053W01 function of a basin section width defined along the ATD 106D. The basin section width can be equal to or greater than the ATD. In example implementations, the sump slope can be a function of a collective basin width determined by the first and second basin sections 510A, 510B. In example implementations, the sump slope can be a function of the basin width of the first or second basin sections 510A, 51 OB.

[00206] Referring to FIGS. 5A and 6, some of the floor 510F of the bottom basin 510 is spaced apart from the plenum(s) 508. Some of the floor 510F is misaligned with the plenum(s) 508. For example, and referring to FIGS. 5A and 6, some of the floor 510F is offset horizontally from the plenum(s) 508, where the horizontal dimension is parallel to the packing depth 106D. Referring to FIGS. 5A and 6, there is no vertical overlap between the floor 510F of the first and second basin sections 510A, 510B and the plenum(s) 508. Referring to FIGS. 5A and 6, the floor 510F of the first and second basin sections 510A, 510B is vertically unobstructed by the plenum(s) 508. Referring to FIGS. 5A and 6, no portion of the plenum(s) 508 vertically overlaps the floor 510F of the first and second basin sections 510A, 510B. Referring to FIGS. 5A and 6, the floor 510F of the first and second basin sections 510A, 510B is not underneath the plenum(s) 508. Referring to FIG. 6, the floor 510F of the first and second basin sections 510A, 510B, and the process streams accumulated in the first and second basin sections 510A, 510B, are not underneath the plenum(s) 508. Referring to FIG. 6, all the portions of the floor 51 OF of the first and second basin sections 510A, 510B and all of the plenum(s) 508 are provided with positions along an axis 510X that is parallel to the packing depth 106D and that starts at a common datum 510D. The positions of any portion of the floor 51 OF of the first and second basin sections 510A, 510B along the axis 51 OX are different from the positions of any part of the plenum(s) 508 along the axis 510X.

[00207] Referring to FIGS. 5A and 6, some of the floor 510F of the bottom basin 510 is vertically aligned with some of the plenum(s) 508. In the example implementation of the Id- shaped bottom basin 510, and referring to FIG. 6, the floor 51 OF along the connection section 510C of the bottom basin 510 is beneath some of the plenum(s) 508, and the remainder of the floor 510F (e.g., of the first and second basin sections 510A, 510B) is offset horizontally from the plenum(s) 508 as described above. The connection section 510C can be defined by connection section walls 510WC extending upwardly from the portion of the floor 51 OF along the connection section 510C. The connection section walls 510WC extend along a direction that is parallel to the end walls 51 OWE. In the example implementation of the bottom basin 510 of FIG. 6, the connection section walls 510WC delimit the only portion of the floor 51 OF of the bottom basin 510 that is located underneath the plenum(s) 508. In the example Attorney Docket No.: 30285-0053W01 implementation of the bottom basin 510 of FIG. 6, the only portion of the plenum(s) 508 that overlies the floor 510F of the bottom basin 510 is along the connection section 510C. Referring to FIG. 6, the plenum(s) 508 includes a plenum connection portion 508C that is positioned above the connection section 510C. A first plenum portion 508A is positioned on one side of the plenum connection portion 508C relative to a direction parallel to the wall axis 509, and a second plenum portion 508B is on another side of the plenum connection portion 508C relative to the direction parallel to the wall axis 509. For example, and referring to FIG. 6, the first plenum portion 508A is positioned adjacent one of the pairs of end walls 510WE of the first and second basin sections 510A, 510B, and the second plenum portion 508B is positioned adjacent the other pair of end walls 51 OWE. In the example implementation of the H-shaped bottom basin 510, and referring to FIG. 6, the floor 51 OF of the bottom basin 510 is offset from the plenum(s) 508 on either side of the connection section 510C.

[00208] By positioning the floor 510F relative to the plenum(s) 508 in the manner described above with respect to FIGS. 5A and 6, the plenum(s) 508 of the contactor wall 502 become more easily accessible to vehicles, equipment or personnel, which can enter the plenum(s) 508 unimpeded by portions of the bottom basin 510 along the entire axial length of the contactor wall 502. This improved access to the interior of the contactor wall 502 can help with maintenance, repair or replacement of componentry of the contactor wall 502 in its interior, such as the drift eliminators 117, the structured packings 116 bordering the plenum(s) 508, the fan stacks 107 and the fans 121. By positioning the floor 510F relative to the plenum(s) 508 in this manner, it becomes unnecessary to build out the bottom basin 510 under the plenum(s) 508, thereby saving on material and labour costs associated with constructing the bottom basin 110. The H-shaped bottom basin 510 described above can be constructed by precasting portions of the bottom basin 510 away from the site where they will be assembled, and transporting the pre-cast sections to the site, which may facilitate assembly of the bottom basin 510. By positioning the floor 510F relative to the plenum(s) 508 in this manner and preventing process streams from accumulating under most of the plenum(s) 508, it can be possible to service components in the interior of the contactor wall 502 once one or more of its gas-liquid contactors 100, 100 A, 100B, 100C, 100D have been deactivated, even while the process streams continue to drain off the packing sections 106A, 106B, thereby providing quicker turnaround during servicing.

[00209] Referring to FIG. 6, the first plenum and second plenum portions 508A, 508B are positioned above a first ground area 520A and a second ground area 520B, respectively. The first and second ground areas 520A, 520B are positioned between the first and second Attorney Docket No.: 30285-0053W01 basin sections 510A, 510B, relative to a direction that is parallel to the axis 510X. The first and second ground areas 520A, 520B are separated from each other by the connection section 5 IOC. Each of the first and second ground areas 520A, 520B are delimited partially by the plenum walls 510WP of the first and second basin sections 510A, 510B, and by the connection section walls 510WC of the connection section 5 IOC. Each of the first and second ground areas 520 A, 520B have a rectangular shape. Each of the first and second ground areas 520A, 520B is elongated and extends along a direction parallel to the collector axis 512. Each of the first and second ground areas 520A, 520B is different from the first basin section 510A, second basin section 510B, and connection section 510C. This difference can take many forms. For example, the main purpose of each of the first and second ground areas 520A, 520B is not to collect liquid, in contrast with the main purpose of the first basin section 510A, second basin section 510B, and connection section 510C. In another example of the difference above, the ground areas 520A, 520B are at grade 500, and at least the walls 510W of the first basin section 510A, second basin section 510B, and connection section 510C are above grade 500. In another implementation, the ground areas 520A, 520B are at approximately at the same height as the grade 500. In another example of the difference above, the ground areas 520A, 520B may be traversed or driven over by vehicles, personnel or equipment, whereas at least the walls 510W of the first basin section 510A, second basin section 510B, and connection section 510C prevent such movement. In another example of the difference above, the ground areas 520A, 520B may be accessed while the gas-liquid contactors 100, 100 A, 100B, 100C, 100D of the contactor wall 502 are operating, whereas the first basin section 510A, second basin section 510B, and connection basin section 510C are not accessible while the gas-liquid contactors 100, 100 A, 100B, 100C, 100D are operating.

[00210] In example implementations, and referring to FIG. 6, the first and second ground areas 520A, 520B are defined by, or include, the ground. In example implementations, and referring to FIG. 6, one or both of the first and second ground areas 520A, 520B are defined by a substrate 510S placed over the ground or defining part of the ground. For example, in example implementations, each substrate 510S is composed of gravel laid over a ground liner. For example, in example implementations, each substrate 510S is composed of a gravel layer resting on a PVC liner applied onto the ground. The first basin section 510A, the second basin section 510B, and the connection section 510C are made of one or more materials of construction, non-limiting examples of which include steel and concrete, in any combination, with or without a protective coating or lining applied on surfaces that are in contact with the process streams. In example implementations, and in yet another example of the differences Attorney Docket No.: 30285-0053W01 between the first and second ground areas 520 A, 520B and the first basin section 510A, second basin section 51 OB, and connection section 510C, the first and second ground areas 520 A, 520B are free of the material of construction of the first basin section 510A, second basin section 510B, and connection section 510C. In example implementations, the first and second ground areas 520A, 520B are not made of any materials, or are not made of same material(s) of construction as the first basin section 510A, second basin section 51 OB, and connection section 510C.

[00211] In example implementations, the first and second ground areas 520 A, 520B are prepared to withstand varying loads that can be applied by personnel, vehicles and/or machinery. In example implementations, the first and second ground areas 520A, 520B can be configured to receive load-bearing elements, which can be, but are not limited to, mats, boards, planks, panels, rods, etc. The load bearing elements may facilitate a load applied by personnel, vehicles and/or machinery.

[00212] Each substrate 510S can be textured, shaped, sloped or otherwise configured to collect liquid (such as rain or drift from the packing sections 106), and to transfer such liquid elsewhere. In example implementations, and referring to FIG. 6, some or all of each substrate 510S is sloped toward a drain 51 OR that is fluid communication with one or both of the first and second basin sections 510A, 510B. The drain 510R may take any suitable form to achieve the functionality ascribed to it herein, such as a French drain sloped toward the sump 516. A height of the substrate 510S is less than a height of the walls 510W, where all heights are measured vertically from a common reference.

[00213] Other shapes for the first and second basin sections 510A, 510B and for the first and second ground areas 520A, 520B are possible. Non-limiting examples of planar shapes (when viewed from above, as in FIG. 6) for one or more of the first basin section 510A, the second basin section 510B, the first ground area 520A and the second ground area 520B include: curved, square, triangular, circular, oval and polygonal. Such planar shapes for the first and second basin sections 510A, 510B can match the bird’s eye profile of the packing sections 106.

[00214] In a different implementation of the lower liquid collector 112 and referring to FIG. 7, the lower liquid collector 112 comprises one or more collection pans 601. The collection pan 601 is used to receive liquid from the packing section 106. To receive liquid, the collection pan 601 is fluidly coupled to the packing section 106. The collection pan 601 can be positioned above grade 500. In particular, the collection pan 601 can be positioned at a collector height 110H measured from grade 500 (see, for example, FIG. 8). The collector Attorney Docket No.: 30285-0053W01 height 110H can be within a range of O-1O feet in an example implementation. For example, if the collector height 110H is O-feet, the collection pan 601 will be positioned at grade 500. In a different implementation where the collector height 11 OH is greater than O-feet, the collector pan 601 is positioned above grade 500.

[00215] The collection pan 601 is positioned to fulfill the functions of the lower liquid collectors 112 and is in fluid communication with the packing sections 106. To receive liquid from the packing section 106, the collection pan 601 is positioned underneath the packing section and vertically aligned with the packing section 106.

[00216] Referring to FIG. 7 and FIG. 8, to receive liquid from the packing section 106, the collection pan 601 can be of a shape that can be, but is not limited to, a rectangular shape. To receive and transfer the liquid, the collection pan 601 comprises a pan floor 61 OF and a plurality of pan walls 601W. The pan floor 61 OF is perimetrically surrounded by the plurality of pan walls 601W, where the plurality of pan walls 601W extend upwardly from the pan floor 61 OF in a direction opposite to a direction of liquid flow. Referring to FIG. 8, when the liquid flows downwards, to collect the liquid in the collection pan 601, the plurality of pan walls 601W extend upwards towards the packing section 106 such that a collecting volume is defined between the plurality of pan walls 601W and the pan floor 610F. A height of the plurality of pan walls 601W is selected to provide sufficient volume in the collection pan 601 to receive and transfer liquid and can vary in different implementations.

[00217] In example implementations, to receive liquid from the packing section 106, the collection pan 601 is positioned underneath and vertically aligned with the packing section 106. In particular, the collection pan 601 is positioned underneath a bottom area 625 of the packing section 106, where the bottom area 625 is defined by a bottom portion of the packing section 106. Referring to FIGS. 7 and 8, an area of the bottom area 625 may be defined as a product of the ATD 106D and the length 166L of the contactor wall 502 along the wall axis 509. When positioned underneath the packing section 106, the plurality of pan walls 601W, which extend towards the bottom area 625, may be pressed against the bottom area 625 in an example implementation. In a different implementation, the plurality of pan walls 601W, may be vertically offset from the bottom area 625. In such an implementation, a space created between the plurality of pan walls 601W and the bottom area 625 can be sealed with a baffle or other comparable bypass reduction/prevention device.

[00218] FIG. 8 is an end view illustration of the collection pan 601 shown in FIG. 7 being positioned at the collector height 11 OH. In the implementation of FIG. 8, the collector height 110H is greater than 0 feet. In the implementation of FIG. 8, the collector height 110H Attorney Docket No.: 30285-0053W01 has a non-zero value such that the collection pan 601 is spaced vertically apart from grade 500. The structural members 115 and at least one base member 125 can be used to position the collection pan 601 at the collector height 110H. In example implementations, the at least one base member 125 is a foundation used in erecting the gas-liquid contactor 100, 100A, 100B,

IOOC, 100D and the structural members 115 extends from the foundation. The structural members 115 can extend from the packing section 106 to grade 500 such that the collection pan 601 is positioned at the collector height 110H. The base member 125, which can be positioned at grade, below grade, or extending from grade, can extend along the wall axis 509 to a length equal to or greater than a length 166L of the at least one contactor wall 502. In example implementations, the structural members 115 can extend from the collection pan 601 towards grade 500 to position the collection pan 601 at the collector height 110H utilizing the structural members 115 and the base member 125.

[00219] In example implementations, the collection pan 601 can be a continuous pan spanning an area equal to or greater than the bottom area 625. In other implementations, the collection pan 601 can comprise, or consist, of a plurality of pan sections 602 that collectively span an area equal to or greater than the bottom area 625. The plurality of pan sections 602 provides modularity to the collection pan 601, and the modularity may be beneficial in assembly, transport, and other comparable aspects. In an exemplary implementation, when used with a dual-cell gas liquid contactor 100, 100 A, 100B, 100C, 100D, each of the pan sections 602 may be positioned below a cell of the gas-liquid contactor 100, 100A, 100B, 100C,

IOOD. In another exemplary implementation, one or more pan sections 602 may be positioned under a cell. Each of the plurality of pan sections 602 will be pressed against each other to prevent liquid bypass and/or air bypass. Seals, gaskets, or other comparable mechanisms can be used to prevent liquid bypass and/or air bypass between the plurality of pan sections 602. In implementations where the collection pan 601 is rectangular in shape, a longest dimension of the collection pan 601 can be oriented perpendicular to the wall axis 509 and parallel to the ATD 106D. In such an orientation, each of the plurality of pan sections 602 will be connected to each other along the longest dimension that is perpendicular to the wall axis 509 and parallel to the ATD 106D.

[00220] In a different implementation, the collection pan 601 may be oriented such that the longest dimension is parallel to the wall axis 509 and perpendicular to the ATD 106D. In such an orientation, each of the pan sections 602 will be connected to each other along the longest dimension, where the longest dimension is parallel to the wall axis 509 and perpendicular to the ATD 106D. Attorney Docket No.: 30285-0053W01

[00221] Referring to FIG. 9, to remove liquid accumulated in the collection pan 601, a network of pipes 603 is fluidly coupled to the collection pan 601 and is configured to transfer liquid from the collection pan 601 to the sump 516. To transfer the liquid from the collection pan 601 to the network of pipes 603, the collection pan 601 can be sloped in example implementations. In example implementations, the collection pan 601 can be positioned parallel to the horizontal or grade.

[00222] Referring to FIGS. 7 and 9, the flow of liquid from the collection pan 601 to the network of pipes 603 can be facilitated by a manifold 607, where the manifold 607 is fluidly coupled to the collection pan 601 and the network of pipes 603. The manifold 607 is positioned to receive liquid from the collection pan 601 and transfer the liquid to the network of pipes 603. In example implementations, and referring to FIG. 9, the manifold 607 is integrated into the pan floor 61 OF. In example implementations, the manifold 607 is connected to the collection pan 601 along one of the plurality of pan walls 601W. To flow liquid towards the manifold 607, the pan floor 61 OF can be sloped towards the manifold 607 in example implementations. For example, if the network of pipes 603 is positioned below the plenum 108, the pan floor 61 OF can be sloped downwardly in a direction from the inlet 1031 of the gasliquid contactor 100, 100A, 100B, 100C, 100D to the plenum 108, along the ATD 106D. In another implementation, if the network of pipes 603 is positioned exterior to a perimeter of the gas-liquid contactor 100, 100 A, 100B, 100C, 100D, the pan floor 61 OF can be sloped from the plenum 108 towards the inlet 1031 along the ATD 106D. In such implementations, an overall length of the network of pipes 603 can be greater than when the network of pipes 603 is within the perimeter of the gas-liquid contactor 100, 100A, 100B, 100C, 100D. In another implementation, the collection pan 601 may be integrated with a flow control mechanism that can be, but is not limited to, an overflow control mechanism. In example implementations, the pan floor 61 OF can not have a slope, and liquid may drain from the collection pan 601 to the manifold 607 via gravity and due to liquid head since the manifold 607 is positioned underneath the collection pan 601.

[00223] In example implementations, and referring to FIG. 9, the network of pipes 603 may comprise a first set of pipes 613 and a second set of pipes 623. The first set of pipes 613 can be fluidly coupled to the packing section 106 via the collection pan 601. Thus, the liquid from the packing section 106 will flow into the collection pan 601, the manifold 607, and then into the first set of pipes 613. In example implementations, each of the first set of pipes 613 is fluidly coupled to the collection pan 601 and is configured to receive the liquid from one cell of the dual-cell gas-liquid contactors 100, 100 A, 100B, 100C, 100D. Referring to FIG. 7, in Attorney Docket No.: 30285-0053W01 implementations where each cell of the gas-liquid contactor 100, 100A, 100B, 100C, 100D is fluidly coupled to one pan section 602, one of the first set of pipes 613 can be fluidly coupled to the pan section 602. In another implementation where the pan sections 602 are used with a cell of the dual-cell gas-liquid contactor 100, 100 A, 100B, 100C, 100D, one or more pipes of the first set of pipes 613 can be fluidly coupled to the pan sections 602. Each of the first set of pipes 613 can include a corresponding flow control mechanism that can be, but is not limited to, a valve. The corresponding flow control mechanism can facilitate the control of liquid into the first set of pipes 613 and into the second set of pipes 623.

[00224] Referring to FIGS. 8 and 9, liquid from the packing section 106 flows through the first set of pipes 613 into the second set of pipes 623. The second set of pipes 623 can be configured to receive liquid from multiple cells of the gas-liquid contactors 100, 100A, 100B,

IOOC, 100D and can be utilized to control the flow of liquid to the sump 516. To do so, in example implementations, each of the second set of pipes 623 can include a corresponding flow control mechanism that can be, but is not limited to, a valve.

[00225] A piping diameter for the first set of pipes 613 and the second set of pipes 623 can be selected to maintain a predetermined flow rate. The length and the positioning of the first set of pipes 613 and the second set of pipes 623 can also be selected to maintain the predetermined flow rate. In example implementations, the network of pipes 603 can be positioned at least partially under the packing section 106. In example implementations, the network of pipes 603 can be positioned in between the bottom area 625 and grade 500. To receive liquid from the collection pan 601 through the manifold 607, the network of pipes 603 can be positioned at a collector height 110H measured from grade 500 that is lower than the height of the collection pan 601 and the manifold 607. In example implementations at least some of the network of pipes 603 can be below grade 500.

[00226] As a contingency system for the gas-liquid contactor 100, 100A, 100B, 100C,

IOOD, and referring to FIGS. 10A and 10B, the gas-liquid contactor 100, 100A, 100B, 100C, 100D comprises a liquid retention system 630. The liquid retention system 630 is used to prevent any overflow of liquid that may occur from the gas liquid contactor 100, 100 A, 100B, 100C, 100D. The liquid retention system 630 can be positioned differently in varying implementations. In example implementations, the liquid retention system 630 can be positioned outside a perimeter defined by the contactor wall 502. In example implementations, the liquid retention system 630 can be partially within the perimeter defined by the contactor wall 502. In example implementations, the liquid retention system 630 can be completely within the perimeter defined by the contactor wall 502. Attorney Docket No.: 30285-0053W01

[00227] In example implementations, and referring to FIGS. 10A and 10B, the liquid retention system 630 comprises the sump 516, at least a portion of the network of pipes 603 extending from the collection pan 601, a collection channel 605, and a pond 617. The portion of the network of pipes 603 associated with the liquid retention system 630 flows the liquid into the sump 516 through the collection channel 605. The collection channel 605 can be used to regulate a liquid level during different operating configurations which can be, but are not limited to, start-up, and shut down. To do so, referring to FIG. 10B, in addition to being fluidly coupled to the sump 516, the collection channel 605 is also fluidly coupled to the pond 617, which can be a reservoir or other comparable containment. In example implementations, for liquid regulation purposes, the collection channel 605 may be fluidly coupled to the pond 617 via a chute, funnel, or other comparable mechanism. The liquid retention system 630 can be differently configured in other implementations.

[00228] During start-up of the gas-liquid contactors 100, 100 A, 100B, 100C, 100D, the pond 617, the collection channel 605, and the sump 516 are loaded with the liquid (e.g., the CCh-laden capture solution 111 and/or the CO2 capture solution 114). When a pump positioned within the sump 516 is activated to flow the liquid to the gas-liquid contactor 100, 100A, 100B, 100C, 100D or transfer the liquid to a downstream process, a liquid level within the sump 516 is reduced. To satisfy and maintain the operating needs of the pump, the pond 617 transfers liquid to the sump 516 through the collection channel 605. The flow of liquid from the pond 617 to the sump 516 can result in the pond 617 being free of the liquid during normal operation of the gas-liquid contactors 100, 100A, 100B, 100C, 100D. Resultantly, the liquid can regulate within the connection channel 605 and the sump 516. During shut down, and in the event liquid is unable to be removed from the sump 516, the collection channel 605 can allow any overflow liquid to flow into the pond 617 from the sump 516 such that all liquid from the contactor wall 502, 1502 is held within the liquid retention system 630.

[00229] The description and one, some, or all of the advantages, and functions of features of the bottom basin 110 of FIGS. 1-2 and the bottom basin 510 of FIGS. 5 A to 6 apply mutatis mutandis to the collection pan 601 of FIGS. 7-10B and vice versa.

[00230] Referring to FIG. 11, the gas-liquid contactor 100, 100A, 100B, 100C, 100D disclosed herein is part of a direct-air-capture (DAC) system 1200 for capturing CO2 directly from atmospheric air, according to one possible and non-limiting example of a use for the gasliquid contactor 100, 100A, 100B, 100C, 100D. One or multiple gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D absorb some of the CO2 from the CO2-laden air 101 using the CO2 capture solution 114 to form the CO2-laden capture solution 111. The CO2-laden capture Attorney Docket No.: 30285-0053W01 solution 111 can be processed to recover the captured CO2 as a CO2 product stream for subsequent use, and to regenerate the alkali hydroxide for use in the CO2 capture solution 114. In example implementations, the CO2 product stream can be delivered downhole and sequestered in a geological formation, subsurface reservoir, carbon sink, or the like. In example implementations, the CO2 product stream can be used for enhanced oil recovery by injecting the CO2 product stream into one or more wellbores to enhance production of hydrocarbons from a reservoir. In example implementations, the CO2 product stream can be fed to a fuel synthesis system, which can include a syngas generation reactor. In example implementations, the CO2 product stream is flowed to a carbon products manufacturing system. [00231] Referring to FIG. 11, the CO2 capture solution 114 needs to be regenerated from the CCh-laden capture solution 111, which can be carried out in a regeneration system 1230 of the DAC system 1200. The regeneration system 1230 functions to process the CCh-laden capture solution 111 (e.g., spent capture solution) to form regenerated CO2 capture solution 114 that is flowed back to the gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D and also recover and/or concentrate the CO2 content laden in the CCh-laden capture solution 111 to form a concentrated carbon stream, for example, CO, a CO2 product stream, or other carbon products. The regeneration system 1230 can be in fluid communication with the bottom basins 110, 510 of the gas-liquid contactor(s) 100, 100 A, 100B, 100C, 100D to receive the CO2-laden capture solution 111. The regeneration system 1230 can be in fluid communication with the top basins 104 of the gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D to flow thereto the regenerated CO2 capture solution 114. Multiple regeneration systems 1230 are possible and within the scope of the present disclosure, and some of these are now described in greater detail. [00232] FIG. 12 shows one possible implementation of the regeneration system 1230 of the DAC system 1200. Referring to FIG. 12, the CCh-laden capture solution 111 flows from the gas-liquid contactor 100, 100A, 100B, 100C, 100D to the regeneration system 1230. The regeneration system 1230 includes a pellet reactor 1210. A slurry of calcium hydroxide 1224 is injected into the pellet reactor 1210. A reaction between the CCh-laden capture solution 111 and the calcium hydroxide 1224 occurs in the pellet reactor 1210. Ca²⁺ reacts with COs²' in the pellet reactor 1210 to form calcium carbonate solids and an aqueous alkaline solution as the CO2 capture solution 114 (such as hydroxide), thereby regenerating the CO2 capture solution 114. For example, potassium carbonate in the CCh-laden capture solution 111 can react with calcium hydroxide to form calcium carbonate and potassium hydroxide, thereby regenerating the CO2 capture solution 114 that includes potassium hydroxide. Attorney Docket No.: 30285-0053W01

[00233] The reaction of the CCh-laden capture solution 111 with Ca(OH)2 causes precipitation of calcium carbonate (CaCCh) onto calcium carbonate particles in the pellet reactor 1210. Further processing of the calcium carbonate solids including, but not limited to, filtering, dewatering or drying, can occur prior to sending the calcium carbonate solids to other process units of the regeneration system 1230, such as a calciner 1216. A stream 1214 of calcium carbonate solids is transported from the pellet reactor 1210 to the calciner 1216. The calciner 1216 calcines the calcium carbonate of the stream 1214 from the pellet reactor 1210 to produce an exhaust gas stream 1218 that includes gaseous CO2 and a stream of calcium oxide (CaO) 1220, possibly by oxy-combustion of a fuel source in the calciner 1216. The exhaust gas stream 1218 is processed to produce a CO2 product stream for sequestration or other uses, thereby removing some of the CChfrom the CCh-laden air 101 processed in the gasliquid contactor 100, 100A, 100B, 100C, 100D. The exhaust gas stream 1218, either directly or after processing, can be provided as the CO2 product stream described herein for use as desired, or for export. The stream of calcium oxide (CaO) 1220 is slaked with water in a slaker 1222 of the regeneration system 1230 to produce the slurry of calcium hydroxide 1224 that is provided to the pellet reactor 1210.

[00234] The stream 1214 of calcium carbonate solids of the DAC system 1200 that is calcined in the calciner 1216 can be produced according to other techniques for capturing CO2 from the CCh-laden air 101. In one example of such other techniques, the gas-liquid contactor 100, 100 A, 100B, 100C, 100D of the DAC system 1200 uses a liquid sorbent, and a carbonate- forming reactor which receives the CCh-laden capture solution 111 includes one or more reactors similar to those used in the Kraft pulping process to form calcium carbonate solids. In another example of such other techniques for producing calcium carbonate solids in the DAC system 1200, the DAC system 1200 is free of a causticization process, and the gas-liquid contactor 100, 100 A, 100B, 100C, 100D uses a sorbent such as a calcium hydroxide slurry and contacts it with air to form the stream 1214 of calcium carbonate solids which are then calcined. [00235] In other implementations, the regeneration system 1230 is free of a calciner and does not produce calcium carbonate solids. In one example of such an alternative regeneration system 1230, some or all of the CCh-laden capture solution 111 can flow to a thermal stripping column that employs steam to desorb CO2 from the CCh-laden capture solution 111, thereby forming the CO2 product stream and the regenerated CO2 capture solution 114 (see, for example, FIG. 13). In another example of such an alternative regeneration system 1230, some or all of the CCh-laden capture solution 111 can flow to an electrochemical system that includes a cell stack, which can include a set of one or more membranes, and a set of electrodes (see, Attorney Docket No.: 30285-0053W01 for example, FIG. 14). The electrochemical system can regenerate the CO2 capture solution 114 from the CCh-laden capture solution 111 by applying an electric potential to an electrolyte including carbon from the CCh-laden capture solution 111. The difference in electric potential causes ion exchange, thereby forming the CO2 product stream and the regenerated CO2 capture solution 114.

[00236] Referring to FIG. 13, the regeneration system 1330 of the DAC system 1300 functions to regenerate an amine-including CO2 capture solution 114. In implementations where the CO2 capture solution 114 includes an amine capture species, the CO2 in the CO2- laden air 101 reacts with the amine capture species to form the CCh-laden capture solution 111 including solid precipitates, an example of which is carbamate. Non-limiting examples of the amine capture species of the CCh-capture solution 114 include, furan-bis(iminoguanidine) (FuBIG), isophorone diamine (IPDA), a hindered amine group having alkanolamine and alcoholic hydroxyl can be used. Examples of the alkanolamine include monoethanolamine (MEA), diethanolamine, triethanolamine, methyldiethanolamine, diisopropanolamine, and diglycolamine. Examples of the hindered amine having alcoholic hydroxyl include 2-amino- 2 -m ethyl- 1 -propanol (AMP), 2-(ethylamino)-ethanol (EAE), and 2-(methylamino)-ethanol (MAE).

[00237] The regeneration system 1330 includes at least a concentrator 1305, a heat exchanger 1309, and a regeneration reactor 1307. The CCh-laden capture solution 111 can include solids (e.g., carbamate solids) and be in the form of a slurry. The slurry is flowed to the concentrator 1305, which functions to increase the concentration of the solids by separating solids from liquids. A solids slurry stream 1321 is generated by the concentrator 1305. The solids slurry stream 1321 includes a higher concentration of solids than the concentration of solids in the CCh-laden capture solution 111. At least some of the liquid separated from the CCh-laden capture solution 111 by the concentrator 1305 forms a separated liquid stream 1323, which can include unreacted CO2 capture solution 114. The separated liquid stream 1323 is flowed back to any suitable component or unit of the gas-liquid contactor(s) 100, 100 A, 100B, 100C, 100D.

[00238] The solids slurry stream 1321 flows to the heat exchanger 1309, where thermal energy from a regenerated, CCh-lean capture solution 1311 is transferred to the solids slurry stream 1321, as described below. The heated solids slurry stream 1321 flows from the heat exchanger 1309 to the regeneration reactor 1307. The heat exchanger 1309 can be considered a preheat heat exchanger that heat integrates a concentrated slurry (e.g., the solids slurry stream 1321) with a higher temperature regenerated capture solution (e.g., the CCh-lean capture Attorney Docket No.: 30285-0053W01 solution 1311). In example implementations, the solids in the heated solids slurry stream 1321 are at least partially regenerated in the heat exchanger 1309 or downstream thereof, releasing CO2, prior to entering the regeneration reactor 1307.

[00239] In example alternative implementations, the heat exchanger 1309 is upstream of the concentrator 1305, relative to a flow direction of the CCh-laden capture solution 111 from the gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D to the concentrator 1305. In such implementations, the heat exchanger 1309 functions to transfer thermal energy from the CCh-lean capture solution 1311 to the CCh-laden capture solution 111 before it undergoes solid-liquid separation in the concentrator 1305. In transferring thermal energy to streams entering the regeneration reactor 1307, the heat exchanger 1309 helps to reduce the duty of the regeneration reactor 1307 in implementations where the regeneration reactor 1307 uses heat to regenerate the CCh-laden capture solution 111. In other implementations, the regeneration system 1330 does not have a heat exchanger.

[00240] In implementations where the regeneration reactor 1307 is, or includes, a packed column, the heated solids slurry stream 1321 flows through packing 1303 within the regeneration reactor 1307. A regeneration heater 1306 supplies a source of heat, such as a stream of heated gas 1317 (e.g., steam), which contacts the heated solids slurry stream 1321 flowing along the packing 1303. In example implementations, the regeneration reactor 1307 includes one or more nozzles for flowing the heated solids slurry stream 1321 onto the packing 1303. In alternate example implementations, the regeneration reactor 1307 includes a column with trays instead of, or in addition to, the packing column. In example implementations, the packing 1303 is non-structured (e.g., random packing).

[00241] By contacting the heated solids slurry stream 1321 and its carbamate solids with the stream of heated gas 1317, the CCh-lean capture solution 1311 (e.g., regenerated CO2 capture solution 114) is generated and a CO2 gas 1319 is desorbed. The CCh-lean capture solution 1311 collects at the bottom of the regeneration reactor 1307. The CCh-lean capture solution 1311 is at a relatively high temperature and is flowed to the heat exchanger 1309 to transfer at least some of its thermal energy to the solids slurry stream 1321 flowing from the concentrator 1305, as described above. In implementations where the regeneration system 1330 does not have a heat exchanger, the CCh-lean capture solution 1311 is flowed directly to one or more components of the gas-liquid contactor(s) 100, 100 A, 100B, 100C, 100D and reused in the gas-liquid contactor(s) 100, 100 A, 100B, 100C, 100D for CO2 capture.

[00242] The CO2 gas 1319 is released from the regeneration reactor 1307 along with water vapor 1318 via a gas discharging line. The mixed gas stream (CO2 gas 1319 and water Attorney Docket No.: 30285-0053W01 vapor 1318) flow from the regeneration reactor 1307 to a condenser 1308. Depending on the capture species of the CO2 capture solution 114, the mixed gas stream can also include volatile amines/organics. The condenser 1308 condenses the water vapor 1318 (and the volatile amines/organics), forms a water stream 1320 (which can have condensable amines/organics), and separates the CO2 gas 1319 from the water stream 1320. The CO2 gas 1319 is released from the condenser 1308 as the CO2 product stream 1325. The CO2 product stream 1325 can be treated or processed as desired, such as by being compressed. The compressed CO2 product stream 1325, either directly or after processing, can be provided for use as desired, or for export. In example implementations, the condensed water stream 1320 flows from the condenser 1308 to the regeneration heater 1306 to be used to generate the stream of heated gas 1317 in the regeneration reactor 1307. In example implementations, the condensed water stream 1320 flows directly to the heat exchanger 1309.

[00243] Other configurations for the regeneration reactor 1307 are contemplated by the present disclosure. For example, in some configurations, the regeneration reactor 1307 does not include a packed column and is thus free of packing. In such a configuration, the regeneration reactor 1307 can be, or can include, any one of the following non-limiting examples of reaction vessels: a tubular reactor, a continuous stirred tank reactor (CSTR) in which reagents, reactants, and solvents flow into the reactor while the products of the reaction concurrently exit the vessel, or a fluidized-bed reactor.

[00244] In implementations where the regeneration reactor 1307 is, or includes, a tubular reactor, the tubular reactor can have an internal heating device (e.g., an electric heating element) and/or an external heating device (e.g., a heating jacket), inlet and outlet ports, and a phase separator or other suitable outlet to permit CO2 to degas from the tubular reactor. In implementations where the regeneration reactor 1307 is, or includes, a CSTR, the CSTR can have an internal heating device (e.g., an electric heating element) and/or an external heating device (e.g., a heating jacket), a mixing element (such as a rotor and/or baffles), inlet and outlet ports, and a phase separator or other suitable outlet to permit CO2 to degas from the CSTR.

[00245] In implementations where the regeneration reactor 1307 is, or includes, a fluidized-bed reactor, the solids slurry stream 1321 can enter the fluidized-bed reactor from a top of the reactor, and a heating medium (e.g., steam) can be heated externally and flowed to the fluidized-bed reactor to fluidize the bed of solids and transfer heat thereto. The fluidized- bed reactor can have a distribution plate or mesh at a bottom thereof to support the solids being fluidized. The fluidized-bed reactor can also have inlet and outlet ports, and a phase separator or other suitable outlet to permit CO2 to degas from the fluidized-bed reactor. Attorney Docket No.: 30285-0053W01

[00246] FIG. 14 illustrates a DAC system 1400 with another example of a regeneration system 1430 which is free of a calciner and does not produce calcium carbonate solids. The regeneration system 1430 is configured to regenerate a C Ch-rich sorbent (e.g., the CCh-laden capture solution 111) received from one or multiple gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D. The regeneration system 1430 includes a carbonate separation subsystem 1404 and a products generation subsystem 1406. The gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D are fluidly coupled to the products generation subsystem 1406 via the carbonate separation subsystem 1404. The gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D provides the CCh-laden capture solution 111 to the carbonate separation subsystem 1404.

[00247] The CCh-laden capture solution 111 can be an aqueous mixture comprising primarily carbonate ions, alkaline metal carbonate (e.g., K2CO3, Na2CCh), or a combination thereof. The CCh-laden capture solution 111 can also include other components in smaller amounts, such as hydroxide ions, alkali metal hydroxide (e.g., KOH, NaOH), water, and impurities. For example, the CO2-laden capture solution 111 can comprise between 0.4 M to 14 M K2CO3 and between 1 M to 10 M KOH. In example implementations, the CO2-laden capture solution 111 can comprise an aqueous Na2COs — NaOH mixture. In example implementations, the CO2-laden capture solution 111 can comprise a mixture of K2CO3 and Na₂CO₃.

[00248] Referring to FIG. 14, the carbonate separation subsystem 1404 can include a caustic evaporator or a crystallizer (or both). In example implementations, the carbonate separation subsystem 1404 can include a nanofiltration unit or a crystallizer (or both). The carbonate separation subsystem 1404 yields a crystalline carbonate hydrate 1414. Crystalline carbonate hydrate 1414 can include carbonate sesquihydrate (M2CO3 1.5 H2O) or an anhydrous carbonate. For example, crystalline carbonate hydrate 1414 can include potassium carbonate sesquihydrate (K2CO3 1.5 H2O). In some examples, the crystalline carbonate hydrate 1414 can include sodium carbonate decahydrate (Na2CCh lO H2O). In some examples, the crystalline carbonate hydrate 1414 can include potassium sodium carbonate hexahydrate (KNaCCh l4 H2O). In example implementations, the crystalline carbonate hydrate 1414 can include a different stoichiometry of water molecules per unit carbonate in the crystalline carbonate (e.g., M2CO3 n H2O where M is an alkali metal and n is an integer or fractional value).

[00249] The products generation subsystem 1406 receives the crystalline carbonate hydrate 1414. In example implementations, the products generation subsystem 1406 includes a dissolving tank 1408 fluidly coupled to an electrochemical cell 1410. In example implementations, the products generation subsystem 1406 can include a caustic evaporator. Attorney Docket No.: 30285-0053W01

[00250] The dissolving tank 1408 can receive the crystalline carbonate hydrate 1414 from the carbonate separation subsystem 1404, a water stream 1420, and a brine stream 1422. In example implementations, a polished aqueous solution can be used instead of or in addition to the water stream 1420. A polished aqueous solution can be substantially free of particulates and dissolved contaminants (e.g., only contain an insignificant amount of particulates and dissolved contaminants, if any). The crystalline carbonate hydrate 1414 dissolves in water and combines with bicarbonate HCO3 in the brine stream 1422 to form a feed solution 1416. The feed solution 1416 can include a bicarbonate HCO3 -rich solution with a mixture of other components such as carbonate and water.

[00251] The electrochemical cell 1410 receives the feed solution 1416 and a water stream 1420. The electrochemical cell 1410 yields at least two product streams including a first product stream 1412 that comprises a hydroxide (regenerated CO2 capture solution 114) and is returned to the gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D for reuse. The second product stream 1428 is sent to a flash tank 1429 where a gaseous CO2 product stream 1424 is partially or fully released from the flash tank 1429 and then sent to one or more processing units (e.g., compression unit, electroreduction subsystem, carbon products manufacturing system, syngas generation reactor). For further details and alternate implementations, reference is made to the patent application entitled “Systems and methods for capturing carbon dioxide and regenerating a capture solution” and published as US 2022/03142707 Al, the entire contents of which are incorporated by reference herein.

[00252] FIG. 18 illustrates a DAC system 1500 with another example of a regeneration system 1530 which is free of a calciner and does not produce calcium carbonate solids. The regeneration system 1530 is configured to regenerate a CCh-rich sorbent (e.g., the CCh-laden capture solution 111) received from one or multiple gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D.

[00253] The present disclosure includes descriptions of capturing carbon dioxide from a source of impure carbon dioxide (e.g., air) under the form of carbon dioxide-derived species and unloading the carbon dioxide-derived species to a carbon dioxide complexing agent by forming a carbonate salt and/or bicarbonate salt that precipitates, crystallizes or otherwise forms as a solid that can be separated from a liquid medium. In example implementations, the carbon unloading is part of the example regeneration system 1530.

[00254] Referring to FIG. 18, a CO2 capture solution 114 includes or is an aqueous sorbent solution comprising one or more sorbent compounds such as an amino acid and/or amine. The CO2 capture solution 114 is flowed, e.g., pumped or gravity-fed, through the one Attorney Docket No.: 30285-0053W01 or multiple gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D which also receive the CO2- laden air 101, thereby forming the CCh-laden capture solution 111 comprising captured carbon dioxide in any of various forms comprising at least one of carbon dioxide and carbon dioxidederived species, such as carbonate ions, bicarbonate ions and/or carbamate species.

[00255] In example implementations, the regeneration system 1530 processes the CCh- laden capture solution 111 to recover the captured CO2 and to regenerate the sorbent to be reused in the CO2 capture solution 114. Referring to FIG. 18, the regeneration system 1530 is in fluid communication with the one or multiple gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D. Once the aqueous CO2 capture solution 114 is sufficiently loaded with CO2, in any of various forms (as CO2-derived species), the CO2-laden capture solution I l l is pumped into a solids formation subsystem 1512, e.g., comprising a crystallizer, to which a complexing agent 1514 (e.g., an iminoguanidine, such as a bis(iminoguanidine) (BIG)) is added. In example implementations, the complexing agent 1514 is introduced in solution, i.e. being solubilized in a solvent, such as water, or in a mixture of solvents. In some other implementations, the complexing agent 1514 is introduced as a suspension, e.g., as a solid being suspended in a solvent (such as water) or in a mixture of solvents. In some other implementations, the complexing agent 1514 is fed to the solids formation subsystem 1512 in the form of solids.

[00256] The complexing agent 1514 reacts with the carbon dioxide-derived species of the CCh-laden capture solution 111 and forms a solid carbon-containing complex such as a salt solid (e.g., carbonate and/or bicarbonate salt of BIG) with lower solubility than that of the (uncomplexed) complexing agent 1514. For example, the formed salt solids can move through the crystallizer, where the salt solids are stirred until they exit as a suspension of unloaded sorbent solution and solid carbon-containing complex. The salt solids (e.g., a carbonate and/or bicarbonate salt solids) thus precipitate out of the CCh-laden capture solution 111, thereby unloading the carbon dioxide content from the CCh-laden capture solution 111 and forming a slurry 1516 comprising the salt solids in the unloaded sorbent solution. The salt solids can be referred to as a CCh-complexed material or carbon-containing complex.

[00257] In example implementations, the carbonate and/or bicarbonate salt solids are separated from the aqueous solution (solid-liquid separation) to produce a solid phase for CO2 desorption. For example, and referring to FIG. 18, the slurry 1516 is flowed to a solid-liquid separation subsystem 1518, e.g., comprising a filtration unit, to recover a solid material 1520 comprising the salt solids (e.g., carbonate and/or bicarbonate salt), and the unloaded sorbent solution 1522. The unloaded sorbent solution 1522 comprises the sorbent being regenerated Attorney Docket No.: 30285-0053W01 into its active form. The unloaded sorbent solution 1522 is flowed back to the one or multiple gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D. In example implementations, the water content of the unloaded sorbent solution 1522 can be reduced using an evaporator unit 1534 to produce a regenerated sorbent solution 1532 that may be redirected to form the aqueous CO2 capture solution 114 being flowed to the one or multiple gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D for reuse in capturing CO2 from air or other dilute gas source.

[00258] Referring to the example implementation of FIG. 18, the separated solid material 1520 (e.g., carbonate material) is further treated in a CO2 recovery subsystem 1524 to release gaseous carbon dioxide as part of the CO2 product stream 1528 and regenerate the uncomplexed complexing agent in a regenerated solid material 1526 (e.g., the iminoguanidine in a non-salt or freebase form). Various techniques can be employed to release the carbon dioxide from the solid material 1520 in the CO2 recovery subsystem 1524. For example, the CO2 recovery subsystem 1524 can heat the solid material 1520 to about 40-160°C, e.g., between 80°C and 60°C, to release CO2 and to thermally regenerate the complexing agent for reuse in further carbon unloading cycles. For example, the CO2 recovery subsystem 1524 can add an acid to react with the iminoguanidine bicarbonate/carbonate salt and generate an iminoguanidine acid salt.

[00259] In example implementations, the DAC system 1500 operates a continuous process. For example, the DAC system 1500 may employ continuous flow gas-liquid contactor(s) 100, 100 A, 100B, 100C, 100D and can continuously operate filtration of solid CCh-complexed material as the solid material 1520 in the solid-liquid separation subsystem 1518. For example, the DAC system 1500 can comprise reusing at least one of the unloaded sorbent solution 1522 (e.g., including an amino acid) and a regenerated CO2 complexing compound 1526 (e.g., a guanidine derivative). For example, the DAC system 1500 can comprise reusing both the unloaded sorbent solution 1522 (e.g., including an amino acid) and the regenerated CO2 complexing compound 1526 (e.g., a guanidine derivative).

[00260] In example implementations, at least one of the gas-liquid contactor(s) 100, 100A, 100B, 100C, 100D and the regeneration system 1530 are operated batch-wise or semi- continuously. For example, the regeneration by solids formation in the solids formation subsystem 1512 can be operated continuously while the solid-liquid separation subsystem 1518 can be operated batch-wise or semi-continuously. For example, the solids formation subsystem 1512 can be operated batch-wise or semi-continuously.

[00261] In example implementations, because CO2 is recovered from the solid material 1520 (e.g., BIG carbonate/bicarbonate complex) to form part of the CO2 product stream 1528, Attorney Docket No.: 30285-0053W01 the CO2 recovery stage/step in the CO2 recovery subsystem 1524 can operate on a relatively small quantity (mass and volume) of solid material 1520. This batch operation can minimize the consumption of energy because, to the extent the carbon dioxide is present in a very high concentration in a low-mass vehicle, i.e. solid material 1520 such as a BIG carbonate, energy is not wasted heating liquid that does not contain appreciable quantities of CO2.

[00262] In example implementations, the regenerated solid material 1526 of FIG. 18 can be a partially regenerated material, e.g., which comprises a carbonate/bicarbonate salt of BIG. The partially regenerated material can be made by stopping the regeneration operation before it reaches 100% of the carbonate/bicarbonate salt of BIG is regenerated back to an uncomplexed form of regenerated material. For example, after a known duration at specific temperature and pressure conditions, a desired proportion of non-regenerated material (e.g., carbonate/bicarbonate salt of BIG) is present.

[00263] As used herein, a “carbon dioxide-derived species” is a compound or ion that is not carbon dioxide but was produced directly or indirectly from carbon dioxide. In many cases, the carbon dioxide-derived species is present as an ion or solute in a solution such as an aqueous solution. In example implementations, the carbon dioxide-derived species comprises a carbonate ion, a bicarbonate ion, a carbamate, or any combination thereof. In some cases, a carbon dioxide-derived species is produced by contacting carbon dioxide or a source of impure carbon dioxide such as air or flue gas with a CO2 capture species (also referred to as sorbent), such as at least one of an amine, an amino acid, or an inorganic base. As an example, the contacting can occur in a gas-liquid contactor for capturing CO2 from the source of impure carbon dioxide using the CO2 capture species to form the carbon dioxide-derived species. For example, the CO2 capture species interacts with gaseous carbon dioxide from the source of impure carbon dioxide to convert the carbon dioxide to carbamate, carbonate ion, and/or bicarbonate ion, each of which is an example of a carbon dioxide-derived species.

[00264] Carbon dioxide complexing agent” or “complexing agent” refers to any compound that can selectively complex with carbon dioxide either directly or via carbon dioxide-derived species. In complexed form, a carbon-dioxide complexing agent can form a salt, such as a carbonate or bicarbonate. In certain implementations, the carbon dioxide complexing agent is an unsaturated nitrogenous compound including an imine, an amidine, a multifunctional guanidine derivative and any combinations thereof. More specific examples of the unsaturated nitrogenous compounds include an iminoguanidine such as a bis(imino)guanidine (BIG), a tris(imino)guanidine (TRIG), and a di-iminoguanidium compound. The unsaturated nitrogenous compound can be in freebase or salt form. In example Attorney Docket No.: 30285-0053W01 implementations, the carbon dioxide complexing agent is a nitrogenous acid salt such as an acid salt of an iminoguanidine (e.g., a bis(imino)guanidine or tris(imino)guanidine of the present disclosure), including but not being limited to a hydrochloric acid, a hydrobromic acid, a hydroiodic acid, a sulfuric acid, a nitric acid, a boric acid, an acetic acid, a phosphoric acid, a formic acid, a benzoic acid, a citric acid, a tartaric acid, an oxalic acid, a fumaric acid, a malonic acid, a succinic acid, a lactic acid of an iminoguanidine and analogs thereof. In example implementations, mixtures of at least two carbon dioxide complexing agents are used in processes and methods described herein. For example, two or more BIG compounds (e.g., BIG freebases and/or BIG acid salts) can be used to form at least one of a carbonate salt or a bicarbonate salt of the BIG compound in a crystallizer of a carbon dioxide capture system. In another example, a BIG compound is used in mixture with a tris(imino)guanidine compound as carbon complexing mixture to form at least one of a carbonate salt and/or a bicarbonate salt in a crystallizer of a carbon dioxide capture system. Additional description of the carbon dioxide capture system and related process is provided further below.

[00265] As used herein, the term “freebase” refers to the neutral form of a molecule/compound. In the context of iminoguanidines, the term “freebase” refers to the neutral form of an iminoguanidine. Examples of freebases of the present disclosure can include specific BIGs (e.g., glyoxal bis(imino)guanidine). Salts are generally not freebases. Hence, BIG salts such as BIG hydrochlorides, BIG carbonates, BIG bicarbonates, BIG sulfates, BIG nitrates, etc. are not freebases. However, an unprotonated BIG without an associated anion can be a freebase

[00266] The regeneration system 1230, 1330, 1430, 1530 can include liquid distribution pipes, solids conveying equipment, filtration systems, intermediate components like storage vessels, and/or an assembly of components which function cooperatively to regenerate the CO2 capture solution 114. The regeneration system 1230, 1330, 1430 also includes pumps which flow liquids to and from the regeneration system 1230, 1330, 1430. The regeneration system 1230, 1330, 1430 can be part of the gas-liquid contactor 100, 100A, 100B, 100C, 100D or separate therefrom.

[00267] Referring to FIG. 15, a method 1600 of capturing CO2 from atmospheric air is disclosed. At 1602, the method 1600 includes flowing the atmospheric air (e.g., the CCh-laden air 101) along a first horizontal direction through a first packing section (e.g., the packing section 106A). At 1604, the method 1600 includes flowing the atmospheric air along a second horizontal direction through a second packing section (e.g., the packing section 106B). The second horizontal direction is opposite to the first horizontal direction. At 1606, the method Attorney Docket No.: 30285-0053W01

1600 includes flowing the CO2 capture solution 114 along the first and second packing sections 106A, 106B to absorb CO2 from the atmospheric air into the CO2 capture solution 114 and to form the CCh-lean gas stream 105. At 1608, the method 1600 includes collecting the CO2 capture solution 114 with the lower liquid collector 112 positioned beneath the first packing section 106 A and beneath the second packing section 106B. At 1610, the method 1600 includes flowing the CCh-lean gas stream 105 through the plenum 108, 508 between the first and second packing sections 106 A, 106B and overlying the ground area 110M, 520 A, 520B that is spaced horizontally apart, and separate from the lower liquid collector 112. In example implementations, the method 1600 describes the flow path of gases through each gas-liquid contactor 100, 100A, 100B, 100C, 100D and through portions of its plenum 108, 508 which do not overly the floor 110F, 510F of the bottom basin 110, 510. In example implementations, the method 1600 describes operating a gas-liquid contactor 100, 100A, 100B, 100C, 100D in which the floor 110F, 51 OF of the bottom basin 110, 510 is absent beneath some or all of the plenum 108, 508.

[00268] Referring to FIG. 16, a method 1800 of performing maintenance on the gasliquid contactor 100, 100A, 100B, 100C, 100D is disclosed. At 1802, the method 1800 includes removing structure delimiting part of the plenum 108, 508 to provide access to the ground area 110M, 520A, 520B delimited by the lower liquid collector 112. Non-limiting examples of structure that can be removed at 1802 include one or more of the structural members 115 and one or more of the dividing walls 1525. At 1804, the method 1800 includes accessing the ground area 110M, 520 A, 520B. Accessing the ground area at 1804 can include driving along the ground area 110M, 520A, 520B. Accessing the ground area at 1804 can include enabling personnel or equipment to travel along, or over, the ground area 110M, 520 A, 520B. At 1806, the method 1800 includes performing maintenance on components of the gas-liquid contactor 100, 100A, 100B, 100C, 100D from the ground area 110M, 520A, 520B. In example implementations, the maintenance of 1806 can be performed from the plenum side 51 OP of one or both of the first and second basin sections 510A, 510B.

[00269] FIG. 17 is a schematic diagram of a control system (or controller) 1700 for one or more systems, units and apparatuses of the present disclosure, such as for the DAC system 1200, 1300, 1400, 1500, or for features thereof such as the gas-liquid contactor 100, 100A, 100B, 100C, 100D and the regeneration system 1230, 1330, 1430. The control system 1700 can be used for the operations described in association with any of the computer-implemented methods described previously, for example as or as part of the control system 999 or other controllers described herein. Attorney Docket No.: 30285-0053W01

[00270] The control system 1700 is intended to include various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The control system 1700 can also include mobile devices, such as personal digital assistants, cellular telephones, smartphones, and other similar computing devices. Additionally, the system can include portable storage media, such as, Universal Serial Bus (USB) flash drives. For example, the USB flash drives can store operating systems and other applications. The USB flash drives can include input/output components, such as a wireless transmitter or USB connector that can be inserted into a USB port of another computing device.

[00271] The control system 1700 includes a processor 1710, a memory 1720, a storage device 1730, and an input/output device 1740. Each of the components 1710, 1720, 1730, and 1740 are interconnected using a system bus 1750. The processor 1710 is capable of processing instructions for execution within the control system 1700. The processor 1710 can be designed using any of a number of architectures. For example, the processor 1710 can be a CISC (Complex Instruction Set Computers) processor, a RISC (Reduced Instruction Set Computer) processor, or a MISC (Minimal Instruction Set Computer) processor.

[00272] In one implementation, the processor 1710 is a single-threaded processor. In example implementations, the processor 1710 is a multi -threaded processor. The processor 1710 is capable of processing instructions stored in the memory 1720 or on the storage device 1730 to display graphical information for a user interface on the input/output device 1740.

[00273] The memory 1720 stores information within the control system 1700. In one implementation, the memory 1720 is a computer-readable medium. In one implementation, the memory 1720 is a volatile memory unit. In example implementations, the memory 1720 is a non-volatile memory unit.

[00274] The storage device 1730 is capable of providing mass storage for the control system 1700. In one implementation, the storage device 1730 is a computer-readable medium. In various different implementations, the storage device 1730 can be a floppy disk device, a hard disk device, an optical disk device, or a tape device.

[00275] The input/output device 1740 provides input/output operations for the control system 1700. In one implementation, the input/output device 1740 includes a keyboard and/or pointing device. In example implementations, the input/output device 1740 includes a display unit for displaying graphical user interfaces.

[00276] In example implementations, the processor 1710 is configured to execute a machine learning model (e.g., an artificial intelligence model) that employs multiple layers of Attorney Docket No.: 30285-0053W01 models to generate an output for a received input. A deep neural network is a deep machine learning model that includes an output layer and one or more hidden layers that each apply a non-linear transformation to a received input to generate an output. In some cases, the neural network may be a recurrent neural network. A recurrent neural network is a neural network that receives an input sequence and generates an output sequence from the input sequence. In particular, a recurrent neural network uses some or all of the internal state of the network after processing a previous input in the input sequence to generate an output from the current input in the input sequence. The machine learning model executed by the processor 1710 can be, for example, a deep-learning neural network or a "very" deep learning neural network. For example, the machine learning model executed by the processor 1710 can be a convolutional neural network or a recurrent network. The machine learning model can have residual connections or dense connections.

[00277] In example implementations, the machine learning model executed by the processor 1710 is an ensemble of models that may include all or a subset of the architectures described above.

[00278] In example implementations, the machine learning model executed by the processor 1710 is a graph neural network (GNN). GNNs are a designed to process data that can be represented in a graph form and feature pairwise message passing to enable iterative updating of node representation of the graph data.

[00279] In example implementations, the machine learning model executed by the processor 1710 can be a feedforward auto-encoder neural network. For example, the machine learning model executed by the processor 1710 can be a three-layer auto-encoder neural network. The machine learning model executed by the processor 1710 may include an input layer, a hidden layer, and an output layer. In example implementations, the neural network has no recurrent connections between layers. Each layer of the neural network may be fully connected to the next, e.g., there may be no pruning between the layers. The neural network may include an optimizer for training the network and computing updated layer weights. In example implementations, the neural network may apply a mathematical transformation, e.g., a convolutional transformation or factor analysis to input data prior to feeding the input data to the network.

[00280] In example implementations, the machine learning model executed by the processor 1710 can be a supervised model. For example, for each input provided to the model during training, the machine learning model can be instructed as to what the correct output should be. The machine learning model executed by the processor 1710 can use batch training, Attorney Docket No.: 30285-0053W01 e.g., training on a subset of examples before each adjustment, instead of the entire available set of examples. This may improve the efficiency of training the model and may improve the generalizability of the model. In example implementations, the machine learning model executed by the processor 1710 may be an unsupervised model. For example, the model may adjust itself based on mathematical distances between examples rather than based on feedback on its performance. In example implementations, the machine learning model executed by the processor 1710 can provide suggested additional data that could further improve the output of the machine learning model.

[00281] Certain features described can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The apparatus can be implemented in a computer program product tangibly embodied in an information carrier, e.g., in a machine-readable storage device for execution by a programmable processor; and method steps can be performed by a programmable processor executing a program of instructions to perform functions of the described implementations by operating on input data and generating output. The described features can be implemented advantageously in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. A computer program is a set of instructions that can be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[00282] Suitable processors for the execution of a program of instructions include, by way of example, both general and special purpose microprocessors, and the sole processor or one of multiple processors of any kind of computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memories for storing instructions and data. Generally, a computer will also include, or be operatively coupled to communicate with, one or more mass storage devices for storing data files; such devices include magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and optical disks. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, such as EPROM, EEPROM, and flash Attorney Docket No.: 30285-0053W01 memory devices; magnetic disks such as internal hard disks and removable disks; magnetooptical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, ASICs (application-specific integrated circuits).

[00283] To provide for interaction with a user, the features can be implemented on a computer having a display device such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor for displaying information to the user and a keyboard and a pointing device such as a mouse or a trackball by which the user can provide input to the computer. Additionally, such activities can be implemented via touchscreen flat-panel displays and other appropriate mechanisms.

[00284] The features can be implemented in a control system that includes a back-end component, such as a data server, or that includes a middleware component, such as an application server or an Internet server, or that includes a front-end component, such as a client computer having a graphical user interface or an Internet browser, or any combination of them. The components of the system can be connected by any form or medium of digital data communication such as a communication network. Examples of communication networks include a local area network (“LAN”), a wide area network (“WAN”), peer-to-peer networks (having ad-hoc or static members), grid computing infrastructures, and the Internet.

[00285] The terms “downstream” and “upstream” are used herein as positional descriptors, to describe the relative position of two or more components as a function of the flow direction of a corresponding liquid or gas. For example, if a first component is described as being downstream of a second component relative to a direction of gas flow, the first component receives the gas flow after the second component. Similarly, if a first component is described as being upstream of a second component relative to a direction of liquid flow, the first component receives the liquid flow before the second component.

[00286] A number of embodiments of the disclosure have been described. Nevertheless, it will be understood that various modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are within the scope of the following claims. Further modifications and alternative embodiments of various aspects will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. It is to be understood that the forms shown and described herein are to be taken as examples of embodiments. Elements and materials can be substituted for those illustrated and described herein, parts and processes can be reversed, and certain features can be utilized independently, all as would be apparent to one skilled in the art after Attorney Docket No.: 30285-0053W01 having the benefit of this description. Changes can be made in the elements described herein without departing from the spirit and scope as described in the following claims.

Claims

Attorney Docket No.: 30285-0053W01 WHAT IS CLAIMED IS:

1. A direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air, the DAC system comprising: at least one contactor wall comprising a plurality of gas-liquid contactors positioned side by side, the at least one contactor wall extending along a wall axis, each gas-liquid contactor of the plurality of gas-liquid contactors comprising: a housing comprising a plurality of structural members; at least one inlet; at least one outlet spaced apart from the at least one inlet; at least one packing section disposed between the at least one inlet and the at least one outlet; and a fan operable to flow the atmospheric air from the at least one inlet to the at least one outlet and along the at least one packing section; and a liquid distribution system fluidly coupled to the at least one packing section and operable to flow a CO2 capture solution along the at least one packing section, the CO2 capture solution configured to absorb CO2 from the atmospheric air, the liquid distribution system comprising at least one liquid collection device configured to hold the CO2 capture solution, the at least one liquid collection device comprising: a lower liquid collector comprising a floor and a plurality of walls extending upwardly from the floor, the lower liquid collector extending along a collector axis parallel to the wall axis, the floor positioned beneath the packing sections of the plurality of gas-liquid contactors; and a regeneration system in fluid communication with the liquid distribution system to receive the CO2 capture solution, the regeneration system configured to regenerate the CO2 capture solution and form a CCh-lean liquid to return to the plurality of gas-liquid contactors.

2. The DAC system of claim 1, wherein the lower liquid collector has a cross- sectional shape defined in a plane normal to the vertical, the cross-sectional shape forming an H.

3. The DAC system of any one of claims 1 or 2, comprising at least one surge tank spaced apart from the at least one contactor wall and in fluid communication with the lower liquid collector. Attorney Docket No.: 30285-0053W01

4. The DAC system of any one of claims 1 to 3, wherein the at least one liquid collection device comprises at least one top basin positioned above the at least one packing section and configured to flow the CO2 capture solution to the at least one packing section.

5. The DAC system of any one of claims 1 to 4, wherein: the at least one packing section comprises an upper arrangement of packing and a lower arrangement of packing, the upper and lower arrangements of packing separated by a vertically-extending gap; and the at least one liquid collection device comprises at least one redistribution basin positioned in the vertically-extending gap, the at least one redistribution basin configured to receive the CO2 capture solution from the upper arrangement of packing and flow the CO2 capture solution to the lower arrangement of packing.

6. The DAC system of any of claims 1 to 5, wherein the regeneration system comprises an electrochemical system configured to regenerate the CO2 capture solution and produce a CO2 product stream, the electrochemical system comprising: a carbonate separation subsystem configured to receive the CO2 capture solution and separate at least a portion of carbonate products from the CO2 capture solution; and an electrochemical cell fluidly coupled to the carbonate separation subsystem, the electrochemical cell configured to: receive a feed solution and a water stream; and yield at least two product streams including a first product stream that comprises the CCh-lean liquid.

7. The DAC system of claim 6, wherein the electrochemical cell is configured to yield the CCh-lean liquid comprising hydroxide for the plurality of gas-liquid contactors.

8. The DAC system of claim 6 or 7, wherein the CO2 capture solution comprises at least one of: KOH, NaOH, or a combination thereof.

9. The DAC system of any one of claims 1 to 5, wherein the regeneration system comprises at least one reactor configured to react, via a causticization reaction, slaked lime (Ca(0H)2) and the CO2 capture solution to produce hydroxide and calcium carbonate (CaCO₃) solids. Attorney Docket No.: 30285-0053W01

10. The DAC system of claim 9, wherein the regeneration system comprises a calciner configured to calcine the calcium carbonate solids and produce an exhaust gas stream comprising a CO2 product stream.

11. The DAC system of any one of claims 1 to 10, wherein the at least one contactor wall comprises a plurality of contactor walls, each contactor wall of the plurality of contactor walls spaced apart from an adjacent contactor wall of the plurality of contactor walls.

12. The DAC system of any one of claims 1 to 11, wherein the regeneration system is configured to provide a CO2 product stream.

Attorney Docket No.: 30285-0053W01

13. A direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air, the DAC system comprising: at least one contactor wall comprising a plurality of gas-liquid contactors positioned side by side, the at least one contactor wall extending along a wall axis, each gas-liquid contactor of the plurality of gas-liquid contactors comprising: a housing comprising a plurality of structural members; at least one inlet; at least one outlet spaced apart from the at least one inlet; at least one packing section disposed between the at least one inlet and the at least one outlet, the at least one packing section comprising a first packing section and a second packing section spaced apart from the first packing section by a plenum; and a fan operable to flow the atmospheric air from the at least one inlet, through the first packing section and the second packing section along a predominantly horizontal flow direction, into the plenum, and to the at least one outlet; and a liquid distribution system fluidly coupled to the at least one packing section and operable to flow a CO2 capture solution along a liquid travel dimension, the liquid travel dimension being predominantly vertically downward through the first packing section and through the second packing section, the CO2 capture solution configured to absorb CO2 from the atmospheric air, the liquid distribution system comprising at least one liquid collection device configured to hold the CO2 capture solution, the at least one liquid collection device comprising: a lower liquid collector comprising a floor and a plurality of walls extending upwardly from the floor, the lower liquid collector extending along a collector axis, the floor positioned beneath the packing sections of the plurality of gas-liquid contactors, at least some of the floor offset horizontally from the plenum.

14. The DAC system of claim 13, wherein the lower liquid collector is a collection pan, the collection pan comprising a pan floor and a plurality of pan walls, the pan floor perimetrically surrounded by the plurality of pan walls, the pan floor being positioned at a collector height defined from the pan floor to grade.

15. The DAC system of claim 14, wherein the structural members extend from the at least one packing section to grade. Attorney Docket No.: 30285-0053W01

16. The DAC system of any one of claims 14 or 15, wherein the at least one packing section comprises a bottom portion defining a bottom area, the pan floor being continuous and defining an area being equal to or greater than the bottom area.

17. The DAC system of any one of claims 14 or 15, wherein the collection pan comprises a plurality of pan sections and the at least one packing section comprises a bottom portion defining a bottom area of the at least one packing section, the plurality of pan sections collectively spanning an area equal to or greater than the bottom area.

18. The DAC system of any one of claims 13 to 17, comprising a liquid retention system configured to regulate a liquid level in the plurality of gas-liquid contactors, the liquid retention system fluidly coupled to the lower liquid collector.

19. The DAC system of claim 13, wherein the lower liquid collector comprises a bottom basin, the bottom basin comprising: a first basin section extending along a first basin section axis parallel to the wall axis; and a second basin section spaced apart horizontally from the first basin section and extending along a second basin section axis parallel to the first basin section axis, the first and second basin sections in fluid communication.

20. The DAC system of claim 19, wherein the bottom basin is positioned adjacent to grade.

21. The DAC system of any of claims 19 or 20, wherein the first basin section and the second basin section are in fluid communication via a connection section of the bottom basin, the connection section extending between the first and second basin sections.

22. The DAC system of claim 21, wherein a floor of the connection section is beneath part of the plenum and a remainder of the floor is offset horizontally from the plenum.

23. The DAC system of any one of claims 13 to 22, wherein the at least one liquid collection device comprises a sump in fluid communication with at least one of the first basin section or the second basin section. Attorney Docket No.: 30285-0053W01

24. The DAC system of any one of claims 21 or 22, wherein the plenum comprises: a plenum connection portion above the connection section; a first plenum portion on one side of the plenum connection portion relative to a direction parallel to the wall axis; and a second plenum portion on another side of the plenum connection portion relative to the direction parallel to the wall axis.

25. The DAC system of claim 24, wherein: the first basin section, the second basin section and the connection section comprise at least one material of construction; and the first basin section, the second basin section and the connection section delimit a ground area positioned underneath the first plenum portion and underneath the second plenum portion, the ground area being free of the at least one material of construction.

26. The DAC system of claim 25, wherein the ground area comprises a substrate and a drain in fluid communication with the bottom basin.

27. The DAC system of any one of claims 19 to 26, wherein the lower liquid collector has a cross-sectional shape defined in a plane normal to the vertical, the cross- sectional shape forming an H.

28. The DAC system of claim 13, wherein: the lower liquid collector comprises a first portion extending parallel to the wall axis and a second portion spaced apart horizontally from the first portion and extending parallel to the wall axis, the first and second portions in fluid communication; the floor of the first portion is underneath the first packing sections of the plurality of gas-liquid contactors; and the floor of the second portion is underneath the second packing sections of the plurality of gas-liquid contactors. Attorney Docket No.: 30285-0053W01

29. The DAC system of claim 28, wherein: each of the first portion and the second portion comprises a side extending parallel to the wall axis between opposed ends of the respective portion; and the at least one liquid collection device comprises a sump in fluid communication with at least one of the first portion and the second portion, the sump disposed on the side of the at least one of the first portion and the second portion between the opposed ends of the respective portion.

30. The DAC system of any one of claims 13 to 29, comprising at least one surge tank spaced apart from the at least one contactor wall and in fluid communication with the lower liquid collector.

31. The DAC system of claim 13, wherein at least some structural members of the plurality of structural members are mounted to at least some walls of the plurality of walls.

32. The DAC system of claim 13, wherein: each of the first packing section and the second packing section define a plenum side facing the plenum, and an outer side opposite to the plenum side along the predominantly horizontal flow direction; the plurality of walls comprise plenum walls on the plenum side of the first packing section and the second packing section, and outer walls on the outer side of the first packing section and the second packing section; and at least some structural members of the plurality of structural members are mounted to the plenum walls and to the outer walls.

33. The DAC system of any one of claims 13 to 32, wherein the at least one liquid collection device comprises at least one top basin positioned above the at least one packing section and configured to flow the CO2 capture solution to the at least one packing section. Attorney Docket No.: 30285-0053W01

34. The DAC system of any one of claims 13 to 33, wherein: the at least one packing section comprises an upper arrangement of packing and a lower arrangement of packing, the upper and lower arrangements of packing separated by a vertically-extending gap; and the at least one liquid collection device comprises at least one redistribution basin positioned in the vertically-extending gap, the at least one redistribution basin configured to receive the CO2 capture solution from the upper arrangement of packing, and flow the CO2 capture solution to the lower arrangement of packing.

35. The DAC system of any one of claims 13 to 34, wherein the at least one contactor wall comprises a plurality of dividing walls, each dividing wall of the plurality of dividing walls being upright, the plurality of dividing walls separating at least the plenums of the plurality of gas-liquid contactors of the at least one contactor wall.

36. The DAC system of any of claims 13 to 35, comprising a regeneration system in fluid communication with the liquid distribution system to receive the CO2 capture solution, the regeneration system configured to regenerate the CO2 capture solution and form a CCh-lean liquid to return to the plurality of gas-liquid contactors.

37. The DAC system of claim 36, wherein the regeneration system comprises an electrochemical system configured to regenerate the CO2 capture solution and produce a CO2 product stream, the electrochemical system comprising: a carbonate separation subsystem configured to receive the CO2 capture solution and separate at least a portion of carbonate products from the CO2 capture solution; and an electrochemical cell fluidly coupled to the carbonate separation subsystem, the electrochemical cell configured to: receive a feed solution and a water stream; and yield at least two product streams including a first product stream that comprises the CCh-lean liquid.

38. The DAC system of claim 37, wherein the electrochemical cell is configured to yield the CCh-lean liquid comprising hydroxide for the plurality of gas-liquid contactors.

39. The DAC system of any one of claims 36 to 38, wherein the CO2 capture solution comprises at least one of: KOH, NaOH, or a combination thereof. Attorney Docket No.: 30285-0053W01

40. The DAC system of claim 36, wherein the regeneration system comprises at least one reactor configured to react, via a causticization reaction, slaked lime (Ca(OH)2) and the CO2 capture solution to produce hydroxide and calcium carbonate (CaCCh) solids.

41. The DAC system of claim 40, wherein the regeneration system comprises a calciner configured to calcine the calcium carbonate solids and produce an exhaust gas stream comprising a CO2 product stream.

42. The DAC system of any one of claims 13 to 41, wherein the at least one contactor wall includes a plurality of contactor walls, each contactor wall of the plurality of contactor walls spaced apart from an adjacent contactor wall of the plurality of contactor walls.

43. A gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air, the gas-liquid contactor comprising: a housing comprising a plurality of structural members; at least one inlet; at least one outlet spaced apart from the at least one inlet; at least one packing section disposed between the at least one inlet and the at least one outlet, the at least one packing section comprising a first packing section and a second packing section spaced apart from the first packing section by a plenum; a fan operable to flow the atmospheric air from the at least one inlet, through the first packing section and the second packing section along a predominantly horizontal flow direction, into the plenum, and to the at least one outlet; and a liquid distribution system fluidly coupled to the at least one packing section and operable to flow a CO2 capture solution along a liquid travel dimension, the liquid travel dimension being predominantly vertically downward through the first packing section and through the second packing section, the CO2 capture solution configured to absorb CO2 from the atmospheric air, the liquid distribution system comprising at least one liquid collection device configured to hold the CO2 capture solution, the at least one liquid collection device comprising: a lower liquid collector comprising a floor and a plurality of walls extending upwardly from the floor, the floor positioned beneath the first packing section and the second packing section of the gas-liquid contactor, at least some of the floor offset horizontally from the plenum. Attorney Docket No.: 30285-0053W01

44. The gas-liquid contactor of claim 43, wherein the lower liquid collector comprises a bottom basin, the bottom basin comprising a first basin section extending along a first basin section axis, and a second basin section spaced apart horizontally from the first basin section and extending along a second basin section axis parallel to the first basin section axis, the first and second basin sections in fluid communication.

45. The gas-liquid contactor of claim 44, wherein the first basin section and the second basin section are in fluid communication via a connection section of the bottom basin, the connection section extending between the first and second basin sections.

46. The gas-liquid contactor of claim 45, wherein the floor of the connection section is beneath part of the plenum and a remainder of the floor is offset horizontally from the plenum.

47. The gas-liquid contactor of any one of claims 43 to 46, wherein the at least one liquid collection device comprises a sump in fluid communication with at least one of the first basin section and the second basin section.

48. The gas-liquid contactor of claim 45, wherein the plenum comprises: a plenum connection portion above the connection section; a first plenum portion on one side of the plenum connection portion relative to a direction parallel to a wall axis, at least one contactor wall extending along a wall axis; and a second plenum portion on another side of the plenum connection portion relative to the direction parallel to the wall axis.

49. The gas-liquid contactor of claim 48, wherein: the first basin section, the second basin section and the connection section comprise at least one material of construction; and the first basin section, the second basin section and the connection section delimit a ground area positioned underneath the first plenum portion and underneath the second plenum portion, the ground area being free of the at least one material of construction.

50. The gas-liquid contactor of claim 49, wherein the ground area is defined by a substrate and a drain in fluid communication with the bottom basin. Attorney Docket No.: 30285-0053W01

51. The gas-liquid contactor of any one of claims 43 to 50, wherein the lower liquid collector has a cross-sectional shape defined in a plane normal to the vertical, the cross-sectional shape forming an H.

52. The gas-liquid contactor of claim 43, wherein: the lower liquid collector comprises a first portion extending parallel to a wall axis, at least one contactor wall extending along a wall axis, and a second portion spaced apart horizontally from the first portion and extending parallel to the wall axis, the first and second portions in fluid communication; the floor of the first portion is underneath the first packing section; and the floor of the second portion is underneath the second packing section.

53. The gas-liquid contactor of claim 52, wherein: each of the first portion and the second portion comprises a side extending parallel to the wall axis between opposed ends of the respective portion; and the at least one liquid collection device comprises a sump in fluid communication with at least one of the first portion and the second portion, the sump disposed on the side of the at least one of the first portion and the second portion between the opposed ends of the respective portion.

54. The gas-liquid contactor of any one of claims 43 to 53, wherein at least some structural members of the plurality of structural members are mounted to at least some walls of the plurality of walls.

55. The gas-liquid contactor of claim 54, wherein: each of the first packing section and the second packing section define a plenum side facing the plenum and an outer side opposite to the plenum side along the predominantly horizontal flow direction; the plurality of walls comprise plenum walls on the plenum side of the first packing section and the second packing section and outer walls on the outer side of the first packing section and the second packing section; and the at least some structural members are mounted to the plenum walls and to the outer walls. Attorney Docket No.: 30285-0053W01

56. The gas-liquid contactor of any one of claims 43 to 55, wherein the at least one liquid collection device comprises at least one top basin positioned above the at least one packing section and configured to flow the CO2 capture solution to the at least one packing section.

57. The gas-liquid contactor of any one of claims 43 to 56, wherein: the at least one packing section comprises an upper arrangement of packing and a lower arrangement of packing; the upper arrangement of packing and the lower arrangements of packing are separated by a vertically-extending gap; and the at least one liquid collection device comprises at least one redistribution basin positioned in the vertically-extending gap, the at least one redistribution basin configured to receive the CO2 capture solution from the upper arrangement of packing, and flow the CO2 capture solution to the lower arrangement of packing.

58. A method of capturing carbon dioxide (CO2) from atmospheric air, the method comprising: flowing the atmospheric air along a first horizontal direction through a first packing section; flowing the atmospheric air along a second horizontal direction through a second packing section, the second horizontal direction being opposite to the first horizontal direction; flowing a CO2 capture solution along the first packing section and the second packing section to absorb CO2 from the atmospheric air into the CO2 capture solution and to form a CCh-lean gas stream; collecting the CO2 capture solution with a lower liquid collector positioned beneath the first packing section and beneath the second packing section; and flowing the CCh-lean gas stream through a plenum between the first packing section and the second packing section and overlying a ground area spaced horizontally apart from the lower liquid collector. Attorney Docket No.: 30285-0053W01

59. A method of performing maintenance on a gas-liquid contactor, the method comprising: removing structure delimiting part of a plenum of the gas-liquid contactor to provide access to a ground area delimited by a lower liquid collector of the gas-liquid contactor; accessing the ground area; and performing maintenance on components of the gas-liquid contactor from the ground area.

60. A bottom basin of a gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air, the bottom basin comprising: a first basin section extending along a first basin section axis; a second basin section spaced apart from the first basin section and extending along a second basin section axis parallel to the first basin section axis; and a connection section extending between the first basin section and the second basin section and fluidly coupling the first and second basin sections, the connection section positioned underneath some of a plenum of the gas-liquid contactor.