Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/74—Iron group metals
  • B01J23/755—Nickel
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/14—Silica and magnesia
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali- or alkaline earth metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
  • B01J27/20—Carbon compounds
  • B01J27/22—Carbides
  • B01J27/224—Silicon carbide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/396—Distribution of the active metal ingredient
  • B01J35/397—Egg shell like
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0215—Coating
  • B01J37/0217—Pretreatment of the substrate before coating
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen; Reversible storage of hydrogen
  • C01B3/02—Production of hydrogen; Production of gaseous mixtures containing hydrogen
  • C01B3/32—Production of hydrogen; Production of gaseous mixtures containing hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide or air
  • C01B3/34—Production of hydrogen; Production of gaseous mixtures containing hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide or air by reaction of hydrocarbons with gasifying agents
  • C01B3/38—Production of hydrogen; Production of gaseous mixtures containing hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide or air by reaction of hydrocarbons with gasifying agents using catalysts
  • C01B3/40—Production of hydrogen; Production of gaseous mixtures containing hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide or air by reaction of hydrocarbons with gasifying agents using catalysts characterised by the catalyst

Definitions

• a promising process technology for the reduction of greenhouse gas emissions is in chemicals production using the Dry Reforming of Methane (DRM reaction), in which CO2 and CH4 convert catalytically to form synthesis gas (CO and Hydrogen “syngas ” is a precursor to many useful chemicals and fuels).
• DRM reaction Dry Reforming of Methane
• CO2 and CH4 convert catalytically to form synthesis gas
• Syngas is a precursor to many useful chemicals and fuels
• the reaction is highly endothermic and substantial amounts of steam are required to avoid formation of solid surface site carbon in practical industrial reactors.
• Surface coking reduces catalyst effectiveness, on-stream time, and concomitant fast deactivation rates lead to frequent catalyst replacement.
• Commercialization of this important reaction approach to reducing greenhouse gas emissions has been limited due to a lack of a practical catalyst system that can run unaffected by coke formation for long run lengths (months to years) on industrial scale catalyst pellets.
• biogas feedstock a combination of CH4 and CO2 (which is natural by-product of anaerobic digestion, AD).
• AD systems are part of waste-water treatment plants and used to decompose food waste or animal manure. Landfills produce significant amounts of biogas as part of the natural destruction of organic matter.
• a practical system to convert this low value biogas stream to a higher value product (synthesis gas) has great commercial value. Sources of biogas are often distributed, and a simple compact tubular conversion technology would have commercial benefit to avoid transmission of biogas for central processing or reduce purification costs to separate CO2 from CH4 for subsequent methane addition to natural gas pipelines.
• the feed gas may comprise methane and carbon dioxide as captured together or separately and then mixed from sources beyond traditional biogas sites.
• the feedstock may comprise carbon dioxide as collected from direct air capture systems, industrial flue gas, or other sources.
• the technology may be considered compact as enabled by larger tube diameters due to the improved heat transfer resulting in fewer tubes, lower costs, and a smaller footprint for a multi-tubular reactor system.
• the catalysts consisted of a 2 nanometer (nm) thick coating of a Ni catalyst around about a 50 nm diameter alumina nanoparticle.
• the nanoparticle catalyst was distributed within a quartz wool where 100 mg of Ni-nanoparticles were placed within a reactor volume consisting of an 8 mm tube diameter and a 0.5-m tube length.
• the highly dispersed packing of nanoparticles is needed to avoid a substantial pressure drop otherwise created by very small particles (2 nanometer). Further this dispersed packing configuration would be unlikely to result in cold spots.
• Solid carbon was measured after testing between 700 and 800 °C for 150 hours with an aluminabased catalyst support material, but no carbon formation was noted for the highly dispersed nanoparticles using an MgO-based support. The amount of carbon deposited is higher at lower temperatures but measurable under reported test conditions.
• Latsiou, et aL, (2022) coat aNi-based catalyst as an eggshell on a gamma-alumina porous extrudate catalyst and tested under DRM conditions. Carbon deposition occurred on tire Ni surface but was reduced by the placement of the eggshell catalyst.
• the invention provides a catalyst capable of catalyzing dry reforming, comprising: a core comprising SiC and/or a core coated with an Al-Si alloy; an oxide-supported Ni orNi alloy disposed on the exterior of the catalyst.
• the invention provides a catalyst pellet capable of catalyzing dry reforming, comprising: a core comprising SiC and Al-Si alloy and comprising less than 5 wt% oxygen, preferably less than 2 wt% oxygen; an intermediate coating disposed over the core, the intennediate coating comprising at least 50% or 70% or at least 90 or 95 wt% of Al-Si alloy; and disposed over the intennediate coating, a coating comprising Ni orNi-alloy supported on an oxide comprising Mg and Ca.
• Ni is preferably in the range of 5 to 25 wt% Ni, or 5 to 20%, or 10 to 15%; in some embodiments the intermediate layer consists essentially of Mg, Ca, Ni and O; in some embodiments the Mg/Ca weight ratio in the range of 0.1 to 10.
• the catalyst is be further characterizable by one or any combination of the properties described herein
• the catalyst may further comprise one or any combination of the following: further comprising an Al or Al alloy coating over the core comprising SiC; having an average thickness of alloy coating at least 5 pm, or at least 100 pm, 200 pm or a range of about 20 to 100 pm; wherein the core further comprises Al-Si; mass ratio of SiC/Al-Si in the range of 5 : 1 to 4/6; or at most 4: 1 or at most 3: l or at most 7/10; or at least 1:1 or at least 1.5 or at least 1.7; or about 2: 1; wherein the catalyst comprises a Ni - based catalyst; and/or having an average thickness of exterior catalyst coating at least 5 pm, or at least 10 pm, or in the range from 5 to 400 pm, 10 to 300 pm, 50 to 350 pm. Note that thickness is measured by SEM of a cross-section of a catalyst, and average calculated from at least 5 representative areas of the cross-section.
• the invention provides a method of making a catalyst, comprising: combining SiC powder and Al-Si powder; adding binder and compressing into a pellet; coating the pellet with alloy pow der, preferably via an aerosol, calcining to form a calcined pellet; coating the calcined pellet with a Ni-based DRM catalyst; and calcining to result in an exterior catalyst coating.
• the method optionally further comprises one or any combination of: wherein the green pellet has a volume of 0.05 to 1 cc. 0.07 to 0.3 cc; alloy powder is aluminum alloy, preferably Al-Si alloy; wherein the alloy comprises 5-25 mass% Si, 5-20%, 8-17%, 10-15%; wherein the calcining to form a calcined pellet is conducted at a temperature of at least 1200 C, 1300 C, 1350 to 1450 C in air; ramping down 2-10 °C, 3- 8 °C; average thickness of alloy coating at least 50 pm, or at least 100 pm, 200 pm; mass ratio of SiC/Al- Si in the range of 5: 1 to 4/6; or at most 4: 1 or at most 3: 1 or at most 7/10; or at least 1: 1 or at least 1.5 or at least 1.7; or about 2: 1; wherein the DRM catalyst comprises a Ni-based catalyst; wherein the catalyst is applied as a slurry'; slurry comprises binders; w'herein the
• Tire invention also includes a catalyst made by any of the methods described here.
• the invention provides a method of reforming, comprising: passing CH4 and CO2 at a pressure of at least 5 barg and a feed Steam:C ratio less than or equal to 1.0 or less than or equal to 0.7 into a reaction chamber comprising a dry reforming catalyst comprising a core comprising SiC; a Ni or Ni alloy disposed on the exterior of the catalyst; reacting the CH4 and CO2 in contact with the catalyst at a temperature of at least 800 °C (at a wall of the reaction chamber) and converting at least 10% or at least 20% or 10 to 25% CO2 for at least 100 hrs or at least 200 hrs without regeneration and having a decrease in CO2 conversion of 1% or less without regenerating the catalyst; and converting at least 30, at least 40, or at least 50, or 30 to 50g CH4 per g Ni per hour and/or converting at least 20, at least 30, or at least 35, or 20 to 40g CO2 per g Ni per hour.
• no observable carbon is deposited on the carbon during this method
• the method of reforming optionally further comprises one or any combination of: the method operating continuously at a pressure of 10 bar(gauge) for at least 5 hours or at least 10 hours without regenerating the catalyst and wherein the coke is not formed on the catalyst; a ratio of CH4 and CO2 in the gas stream at least 0.2, 0.5, 1.0, 1.2; or in range from 0.2 to 2; preheating the gas stream prior to entering the reaction chamber; reacting the CH4 and CO2 at a temperature of at least 775, 800, 825, in the range of 775 to 900, 800 to 850 °C; wherein the temperature refers to the temperature at a wall of the reaction chamber and wherein temperature in the center of the reaction chamber at a distance to the wall measured perpendicular to flow has a temperature in the range of about 125 to 25 °C or 75 to 25 °C lower than the wall temperature; steam:carbon ratio 1.2 or less, 1.0 or less, 0.8 or less, the lower limit may be 0 or 0.2 or more, 0.5
• the invention also provides a refonning system, comprising any of the apparatus, reactants, catalysts and/or conditions described herein.
• the catalyst of the present invention comprises a SiC core.
• Materials referred to herein as “HeatPathTM” comprise a SiC core and have properties of very high thermal conductivity and catalytic effectiveness and may include (but are not limited to) any of the core materials mentioned in US 20210245139 (incorporated herein as if reproduced in full below).
• HeatPathTM pellets coated with a thin Ni-based DRM catalyst create a superior catalyst structure for reducing carbon formation, thus enabling a long-lived commercial DRM process to convert biogas to syngas (CO and H2).
• the highly conductive catalyst pellet core that is substantially dense to catalyst and fluid, coupled with an external active catalyst coating reduces thermal gradients at 1) the wall of the reactor (lower temperature needed to drive the reaction), 2) the center of the endothermic tubular reactor, and 3) eliminates cold spots inside an individual catalyst pellet.
• the wall temperature required to drive heat into the endothermic reaction is lower for equal conversion due to the ease of thermal conduction heat transfer through the HeatPathTM pellets.
• the gradient across the tubular reactor bed in the radial direction is reduced by using the higher thermal conductivity of the superior HeatPathTM catalyst structure.
• the temperature cold spot at tire center of the tubular reactor is less severe than found if a conventional pellet with a lower thermal conductivity were used.
• HeatPathTM reduces carbon formation through a combination of variables - including an improved heat transfer structure, excluded internal pellet porosity to avoid a cold pellet core, and a catalyst composition that is sufficient for limiting carbon formation when operated with thermal control.
• Fig. 1 A schematic of the test stand to collect data with the HeatPath catalyst for DRM.
• Fig. 2 The product ratio of H2/CO as a function of reactor temperature at 1500 hr-1 GHSV, 1: 1 CHuCCT, and S:C ratio near 1 .5 for either 10 barg (open symbol) or 20 barg (closed symbol).
• Fig. 3 Tire product ratio of CO 2 /CO as a function of reactor temperature at 1500 hr-1 GHSV, 1 : 1 CO 2 :CH 4 , and S:C ratio near 1.5 for either 10 barg (open symbol) or 20 barg (closed symbol).
• Fig. 4 Hie conversion of CH 4 or CO2 as a function of feed S:C ratio at 20 barg, 850 C, 1: 1 CO2:CH 4 , and 1500 hr-1 GHSV.
• Fig. 10 Full Pellet stability shown as the reactant or product species % vs time on stream for Steam:Carbon feed ratios of 1.5 and 0.5 at 850 °C, 20 barg, Feed CHyCCE ration I . and 1500 hr-1 GHSV.
• Fig. 12 Equilibrium conversion of CO2 or CH4 at 10 or 20 barg as a function of S:C.
• Fig. 13 Equilibrium conversion of CO2 or CH4 as a function of temperature for Steam: Carbon of 0.3 or 1.5.
• the curves are at equidistant locations within the pellet with the edge of the pellet is the lowest curve and does not exceed 1.
• Carbon activity near the center of the pellet is the top curve and exceeds 1 near the front, and again near the middle region of the reactor length.
• Catalyst supports and catalysts of the present disclosure can be fabricated in any of a variety of shapes, including those known to those skilled in the art as well as those hereafter developed. Suitable shapes include, for example, spheres, cylinders, pellets, beads, lobed cylinders (e.g., bilobe, trilobe, tetralobe, etc.), saddles, wheels, rings, pall rings, Raschig rings, ribbed or grooved cylinders, notched cubes, grooved pyramids, daisy-shaped, and star-shaped pellets.
• the catalysts of the present disclosure can be fabricated as monolithic structures. The catalyst supports can be formed into the desired
• catalyst pellets typically have a characteristic dimension or hydraulic diameter of about 1 mm to 50 mm.
• the density of the catalyst core is from about 60% to 100% of theoretical density, or from about 60% to about 90% of theoretical density, or from about 65% to about 80% of theoretical density.
• Catalysts of the present disclosure can be employed in any of a wide variety of reactor types and configurations, including those known to those skilled in the art as well as those hereafter developed.
• catalysts of the present disclosure can be employed in fixed bed reactors (also referred to as packed bed reactors), fluidized bed reactors, microchannel reactors, membrane reactors, ebullating bed reactors, chromatographic reactors, and moving bed reactors.
• the catalysts of the present disclosure are particularly useful for fixed bed (i.e., packed bed) reactors, wherein a free-flowing catalyst is loaded within a reaction chamber of various cross-sectional shapes such as cylindrical, rectangular, square, or other shape.
• the free- flowing catalyst conforms to the shape of the reaction chamber and is fixed in place for reaction operation.
• the catalyst is preferably fixed in position within the reaction chamber(s), rather than moving as in the case of a fluidized bed reactor.
• the catalysts may be made from powders.
• a powder blend can be mixed with various additives, such as one or more organic binders (polyvinyl alcohol, polyvinyl butyral (“PVB”, ethyl or methylcellulose, and the like), and/or one or more plasticizers (e.g., butyl benzyl phthalate (“BBP”), ethylene glycol, polyethyl glycol, and the like).
• BBP butyl benzyl phthalate
• ethylene glycol polyethyl glycol, and the like
• lubricants such as zinc stearate, steric acid, and/or carbon powders such as graphite can be added to the agglomerated powder to ease the dry pressing operation.
• While dry pressing can be used to form the catalyst cores (e.g., as pellets), various other methods can be used to form the cores such as extrusion, wet pressing, slip casting, isostatic pressing, injection molding, and other common ceramic forming approaches, provided that the process applies sufficient pressure to achieve the targeted density in the green state (>60% of the theoretical density of the blended SiC/Al powders) and cause plastic deformation of the aluminum.
• the pellets can be further subjected to a pre-calcination high temperature heat treatment in a substantially oxygen-deficient environment before being subjected to calcination.
• the pre -calcination heat treatment step may cause the aluminum (or aluminum alloy) particles to sinter (e.g., at temperatures above about 400° C.) and further melt and coalesce (e.g., at temperatures above about
• SUBSTITUTE SHEET (RULE 26) 550° C.) allowing for rearrangement of the microstructure.
• This liquid phase may also further slow or prevent the oxidation of the SiC during subsequent heat treatment at temperatures above 500 °C in air or oxygen-containing environments by preventing oxygen or steam (gas) diffusion into the structure.
• a pre -calcination heat treatment can be performed at a temperature which is the same as, or different from, the calcination temperature, particularly one that is lower.
• the pellets will be calcined following pellet formation (i.e., no pre-calcination heat treatment), at a temperature of 850 to 1450° C., or 900 to 1000° C., for a period of time sufficient to convert the aluminum into an alumina matrix around the SiC grains.
• Calcination is performed in an oxygen-contaming environment, such as oxygen, air, steam, or dilutions of the foregoing with nitrogen, argon, hydrogen and/or another carrier gas.
• the pellets comprising SiC and Al (or Al — Si) are calcined in ambient air, without having to control the amount of oxygen in the calcination environment, thereby reducing costs.
• a fixed bed reactor made of Incoloy 800 had an inner diameter of 0.01905-m and a catalyst zone length of 0.0351-m.
• Hollow AI2O3 tablets (5mm length, 5mm outer diameter, 2.5mm inner diameter) were packed upstream of the 10 cm 3 catalyst reactor volume. Downstream of the catalyst an additional 10 cm 3 of hollow AI2O3 tablets were packed and followed by a modest amount (between 1 to 5 cm 3 ) of AI2O3 wool supported by a Ni wire coil to maintain axial position within the reactor.
• the total reactor volume in the catalyst section was about 10 cm 3 .
• the HeatPathTM core pellet was a cylindrical tablet of approximately 0.006-m in diameter by 0.004- m in height.
• the material comprised about 64wt% SiC and 36wt% of Al-Si.
• the SiC powders were 400 grit (80wt%) and 1200 grit (20wt%) blend and 99.2+% purity as received from Panadyne.
• the spherical Aluminum silicon passivated powders were 3.8-micron average diameter of 11.73wt% Si and 87.9+wt%
• SUBSTITUTE SHEET (RULE 26) Al purity as received from Valimet.
• the core was created by mixing the powders and slowly incorporating a PVB, BBP, and ethanol binder solution using an Eirich mixer. The powder was dried in air before adding steric acid (3.7wt% relative to dry powder total) and carbon lubricants (3.7wt% relative to dry powder total). Pellets were then pressed using a Korsch press until a pellet density between about 70 and 72% of theoretical (in the green state) was achieved for a tablet size of approximately 6 mm in diameter by 4 mm in height. The pellets were then cleaned for sharp edges by tumbling and abrading edges, cleaned with compressed air and coated with an Aluminum suspension (AlumiLok) to approximately 5 weight percent.
• Al purity as received from Valimet The core was created by mixing the powders and slowly incorporating a PVB, BBP, and ethanol binder solution using an Eirich mixer. The powder was dried in air before adding steric acid (3.7wt% relative to dry powder
• the protective alumina (AlumiLok) coating is derived from an Aluminum-Silicon alloy powder, which is deposited on the as-pressed SiC/Al composite core, using aerosol deposition under ambient temperature and pressure.
• the core tablets are tumbled in an oblate “panning'’ vessel to create a cascading action.
• Hie coating could alternatively be performed on pellets on a moving conveyor or in a fluidized bed to achieve similar coating effects.
• an Al-Si alloy powder (Valimet S-2, 1 l-13wt% Si) with a D50 of 3.5 microns was added to a 1 -liter Nalgene container, in which a solution of 300 grams methyl acetate, 72.5 grams alpha terpineol and 27.5 grams screen printing vehicle (V006A, Heraeus) was prepared.
• Tablets (300 g, about 6 mm diameter by 4 mm height) were loaded into a tablet coater (BYC-600, Jiawanshun) with a 60 cm diameter vessel, turning at a rotation rate of 20 RPM for about 0.5h. This operation serves to remove asperities and high-radius-of-curvature features from the tablets. Residue from the polishing process was removed from the chamber prior to coating.
• the protective coating was applied using a tablet coater (BY-200, Jiawanshun) with a 20 cm diameter vessel, turning at a rotation rate of 20 RPM. Coating was aerosol deposited in 10-15 second intervals, alternating with 40-50 second intervals of warm, dry air flow. Between the drying step and subsequent coating steps, the tablets were allowed 15-20 seconds to equilibrate. Coating -dryingequilibration was performed in iterations of 5 cycles, with intermediate weighing to assess the deposited coat weight. As needed, additional coating-drying-equilibration cycles were performed to achieve a deposition target of 0.04 grams of alloy per tablet. It is noted that thinner or thicker coatings might be achieved without significantly altering the approach or resulting structures.
• the pellets with a protective coating were calcined at 1400C and maintained at a dwell temperature for 3 hours.
• the ramp rates were fixed at about 3C per min while ramping up and approximately 5C per min while ramping down in temperature.
• the active catalyst material comprised a Ni-based catalyst that was coated on the exterior of a HeatPathTM core pellet.
• Catalyst 1 was synthesized and is described by the formula 12wt%Ni/A12O3 + MgO + CaO.
• the catalyst powder was prepared by forming a 94.5wt% A12O3 + 4.5wt% CaO + 1.0wt%MgO oxide support powder with a d90 particle size less than 5 microns and a BET surface area of greater than 10 m 2 /g.
• the oxide support powder was then mixed and dispersed with a diluted nickel solution and calcined at 600 degrees Celsius before sieving through a 500-micron mesh.
• the powder material was mixed with a dissolved polyvinyl alcohol and deionized water to form a slurry of about 25 wt% solids.
• the slurry was roll milled with the addition of shiny 7 binders (1.5wt%) consisting of boehmite (Sasol 18N4-80) and PVA, DOW ECOsurf EH-9 surfactant (2wt%), ethylene glycol as a wetting agent (lwt%), polymer innovations DF002 defoamer ( ⁇ 0.5wt%) and acetic acid (0.5wt%) as a viscosity modifier.
• the mixture was milled with ZDC media until the suspension was homogeneous and powder particle size was reduced to less than an average of about 5 microns.
• the slurry was coated on HeatPathTMcore pellets using a spray coating technique where the suspension was sprayed with a hand spray (Paasche 0.75mm head double action - internal mix - siphon feed system millennium airbrush set) while the pellets were shaken in a fine mesh sieve strainer.
• Tire coated pellets were sprayed several times with periodic drying at about 100C to 120C between coats.
• target loading was achieved, the catalyst coated pellets were calcined to 650C in air.
• the resulting coating was measured to have about an average 60-micron average coating thickness with an average loading (with respect to the HeatPathTMcore pellet) of 2.63 weight percent for data presented in Examples 2 and 3.
• the HeatPathTM catalyst was loaded in the reactor by inserting a coiled nickel wire near to the center of the reactor Inconel tube. A small amount of AI2O3 wool was pressed into the top of the tube to rest on the coil followed by 10 cm 3 of alumina hollow tablets, 10 cm 3 of catalyst coated HeatPath pellets (described above), and finally 10 cm 3 of additional alumina hollow tablets.
• Tire tube structure was qualified by testing the reactor without HeatPath pellets to ensure no reaction took place and was visually inspected for material loss or shifting after ‘tapping’ the catalyst loaded reactor tube. The tube was inspected for bypass by ensuring there was no visible light through the bottom of the loaded reactor.
• Tire reactor tube was held between two Thermcraft ceramic refactory heat elements with a setpoint of 850C or an alternative value based on tire reported experimental conditions.
• the catalyst section of the reactor was in the central region of the 0.61-m long tube furnace as estimated by a placement of 0.29-m from the top of the furnace.
• the reactor wall temperature was held constant during the run by a temperature controller which functioned based on a K-type thermocouple tied with a high temperature stable wire to the outer reactor wall.
• the reactor was pressurized using an AliCat Scientific back pressure controller which operates based on a set point and solenoid valve system and can electronically open and shut the valve to generate the necessary reactor operating pressure based off the set point. The controller compensated for flow to maintain the set point pressure automatically.
• the effluent gas stream was measured for flowrate AliCat mass flow meter and product mole fractions were measured by an SRI GC using a I 'CD column with readings taken every 20 minutes.
• Methane conversion is defined by (mass flowrate of methane into the reactor - mass flowrate of methane out of the reactor) divided by the mass flowrate of methane into the reactor.
• CO? conversion is defined by (mass flowrate of CO2 in - mass flowrate of CO2 out) divided by the mass flowrate of CO2 in. A small tracer of nitrogen was added to account for the carbon mass balance given the change in moles during reaction.
• the startup procedure after assembling the loaded reactor tube in the stand included heating up in N2 flowing at 200 seem to 250C at 1 ,5C per min ramp rate.
• S:C is defined throughout by the inlet molar flowrate of steam divided by the sum of the inlet molar flowrates of CO2 and CH4.
• the catalyst activation procedure was initiated when 800C reactor temperature was reached.
• the N2 flow was reduced to 100 seem and CH4 was introduced at 40 seem.
• the pressure controller was set to a target absolute pressure of 10-barg (or higher pressure as specified for the experiment) and the reactor was slowly pressurized to condition over several hours. Once at pressure, flow conditions were set to achieve the target reported inlet flow rates for CO2, CH 4 , N2 (tracer), and H 2 O.
• the catalyst shutdown procedure was to immediately shut off H2O and CH4 while simultaneously starting N2 at 200 seem.
• the vaporizer heating was turned off after feeds were stopped.
• the reactor was immediately cooled to 400C at 10C per min target rate followed by further cooling to room temperature at about 5C per min.
• the N2 gas remained flowing as the system was slowly depressurized to atmospheric conditions after the temperature returned to room temperature.
• Pressure is established at the reactor exit with negligible pressure loss as measured over the reactor bed during reaction conditions as operated at a high absolute pressure between about 10 and 20 barg. Temperature is measured at the reactor wall. A small amount of nitrogen was added to act as a tracer to assess change in moles and calculate reactant mass conversions.
• the HeatPathTM pellets were coated with 0.2535 grams of active catalyst as contained within the about 10 cm 3 reactor volume for a total loading density of about 25.35 kg/m 3 .
• Perfonnance is described in Table 2.1 where the HeatPath results for Catalyst 1 is presented for S:C near or about 1.5 for GHSV at 2450 or 1500 hr-1, feed ratio of CH4:CO2 of 0.87 or 1, pressure at 10 or 20 barg, and temperature from 775 to 850 C. Results are shown as conversion of CH 4 or CO? along with the product ratio based on effluent concentration of H 2 /CO or CO 2 /CO. Catalyst productivity in grams of CH4, CO 2 , or total CH 4 plus CO 2 feed converted per gram of catalyst per hour.
• the total catalyst productivity for conditions tested in Table 2.1 ranges from about 3.4 to 12.6 g/g/h.
• the Steam to carbon (S:C) was varied from 1.5 down to 0.3 at 20 barg and a GHSV of 1500 hr- 1.
• Performance is presented in Table 2.2.
• the total catalyst productivity ranges from about 10 to 15.5 g/g/h.
• Figure 2 the product ratio of H2 to CO are shown as a function of reactor temperature at 10 or 20 barg, 1: 1 CHpCOz, and a S:C near 1.5.
• Figure 3 shows the product ratio of CO 2 to CO under the same conditions.
• the HeatPath tests included 0.2535 grams of catalyst in about 10 cm 3 reactor volume for a loading density about 25.35 kg/m3.
• the comparison full pellet tests made from pellets pressed using Catalyst 1 to the same pellet dimension as the HeatPath tests.
• Tire loaded pellets contained 9.63 grams of catalyst packed within the same 10 cm3 reactor volume for a loading density of about 963 kg/m 3 .
• the HeatPath has only about 2.63% of total catalyst by weight as tested with the equivalent size full pellets.
• Example 3 The composition of Catalyst 1 was based on a 12wt.%Ni doped AEOs-CaO-MgO catalyst powder as described in Example 1. The catalyst was coated on a HeatPath pellet and tested in the apparatus described in Example 2 with a catalyst loading density of 25.35 kg/m3.
• the ratio of catalyst mass loaded between the Full traditional pellet (9.63 grams) and the HeatPath (0.2535 grams) is about 38, meaning that is there is about 38 times less catalyst loaded in the reactor for HeatPath experiments conducted with equal inlet gas flowrates.
• the ratio of total catalyst efficiency in g/g/h at a S:C equal to 1.5 is also about 38 suggesting that the HeatPath coating has a 100% effectiveness, and that the effectiveness of the full traditional pellet is about 2.63%.
• the ratio of catalyst efficiency (in g/g/h) is 27.23 for HeatPath versus the full pellet whereas the amount of catalyst in the full pellet is 38-times HeatPath.
• the “g/g/h” refers to the grams of the total composite catalyst coating (the mass of AI2O3 plus CaO plus MgO plus Ni).
• the site-specific catalyst productivity in grams of CO 2 plus CH 4 converted per gram of Nickel per hour would take the table values and divide by 0.12 for a Ni mass basis.
• HeatPath has a thin catalyst coating and thereby substantially less active catalyst per unit reactor volume.
• the impact of reduced catalyst is not substantial due to the low catalyst effectiveness of the traditional or full pellet under the DRM conditions.
• Tire HeatPath catalyst has an advantage of less propensity for coke formation. After 465 hours of operation time, the HeatPath catalyst did not coke, whereas the full pellet formed undesired solid carbon as shown in Figure 7.
• the HeatPath coated pellets, with a catalyst thickness of about 60 microns, show negligible amounts of carbon formed as seen in Figure 8.
• Carbon observed in the crack and the AlumiLok layer of Figure 8 is due to the ingress of mounting epoxy prior to the epoxy solidification.
• Tire pellets, as shown in Figure 7 and Figure 8 were submerged in an epoxy resin and hardener mixture which is hardened at room temperature overnight.
• the external region of a porous or semi porous structure, as observed with the catalyst and Alumilok layers on HeatPath in Figure 3.2 will have liquidous epoxy infiltrate in the large pores in each layer prior to solidifying. It is clear that epoxy has not infiltrated the full pellet since the outermost region (Point 1 in Figure 7) does not show carbon in about the outermost 100 microns.
• Uris reaction is favored at lower temperatures, especially in about a range of about 500 °C to about 700 C and when CO has the highest partial pressure.
• the CO partial pressure is higher as the system operating pressure increases and when the conversion of CH4 and CO2 are higher.
• Tire reported reaction temperature is 850 °C for the data in Example 3 and ranges from 775 to 850 C for the data in Example 2.
• the reactions are highly endothennic and heat is transferred via the flowing gas to the solid catalyst particles, cold spots inside the reactor and catalyst pellets are formed as the reaction progresses. Deep inside pellets, the reactants diffuse toward the center of the pellet and products diffuse outward. The local residence time for conversion of CH4 and CO2 increases inside the pellet which increases the local concentration of the CO product. The combined effect of a local cold spot and the higher local CO concentration inside the catalyst pellet contributes to the initiation of solid carbon fonnation via the Boudouard reaction. As the solid carbon fonns, active sites are blocked and the overall activity decreases.
• HeatPath offers an advantage to keep the local temperature at the catalyst higher due to the higher thermal conductivity of the pellet, and to simultaneously block interior sites to catalyst infdtration or gas permeation outside the outermost region of the pellet, which keeps the local CO concentration in catalystcontaining regions lower.
• the combined effect reduces the propensity for coke formation when using exemplar catalysts made from Nickel or other active materials for the dry reforming of methane.
• a second catalyst composition (Catalyst 2) was a Ni-based catalyst of 12wt%Ni/MgO.
• the catalyst was formed by initially calcining Magnesium Carbonate at 1100 °C in air to yield tire MgO support powder. The powder was then sieved through a 500-micron mesh. The sieved support MgO powder was wetted with a dilute nickel solution using aerosol dispersion, while being agitated in a high dispersion mixer. The solution was applied using aerosol deposition onto the powder while mixing slowly with intennittent drying at 120 °C until the entire nickel solution was dispersed onto the MgO support powder. The resulting powder was then dried overnight between 100 °C and 120 °C, sieved through a 500-micron mesh, and calcined at 800 degrees °C. The material was again sieved at 500-micron mesh.
• Catalyst 2 was coated on 20 grams of HeatPath pellets using the same approach as described in Example 1. A catalyst loading of 2.97 weight percent was yielded and the coated pellets were tested in the apparatus described in Example 2 with a catalyst loading density of 44.05 kg/m3. Catalyst pellets of 6 mm diameter with a similar but slightly shorter height (2.5 mm vs 4 mm height as described in Example 2) as the HeatPath pellets were prepared by dry pressing the Catalyst 2 powder and then fired at 600 degrees Celsius for 2 hours. Tire full pellets were tested and compared with the same catalyst as coated on HeatPath. Hie catalyst loading density of the Traditional or full pellets was about 1149 kg/m3 and results compared under the same test conditions as HeatPath.
• Example 5 Tire issue of reduced catalyst weight per reactor volume is small due to the low overall effectiveness factor for this conventional pellet and could be overcome with a slight increase in HeaPath coating thickness.
• Hie advantage of the HeatPath catalyst is the minimization or avoidance of carbon formation which allows for extended operation and a more practical catalyst system to implement commercially.
• a third catalyst composition (Catalyst 3) was PGM-based and tested under DRM conditions as coated on HeatPath pellets.
• the catalyst composition was 0.75 wt% Rh, 0.7 wt% Pt on a CcCh-ZrCh-AbOs.
• a catalyst coating density of about 50 kg/m3 was tested in device described in Example 1. The coating thickness was about 40 microns.
• the catalyst was very active for SMR at high temperatures (850 °C) and S:C equal to 1, but relatively poor at converting CO2.
• the catalyst was tested for a total cumulative 550 hours with a steam to carbon of about 1. There was no observation of carbon formation. Data is shown in Table 5.1 with varying total pressure from about 12 to 20 barg and GHSV of either 5000 or 12000 hr 1 .
• the conversion of CH4 or CO2 as a function of reactor pressure from 12 to 20 bar is shown in Figure 11 .
• the activation energy (Eai) for the four reactions respectively are as follows: 231, 221, 60.5, and 231 kJ/mol.
• the adsorption energy for methane, water, and CO2 are 17.6, -18.9, -17.1 kJ/mol respectively.
• the values of ki’s in units for reaction rates in mol/s are as follows: 3.66el2, 3.54el2, 3.35el2, 6.48el2.
• the values of Ki's in units of inverse bar are 7.75, 0.89, and 4.73.
• the calculated carbon activity is consistent with the observed locations of carbon formation as measured using SEM EDS on the tested catalysts.
• the relative concentration of CO at the center to edge of the pellet as a function of reactor length for the full pellet is shown in Figure 14.
• the corresponding reactor bed temperature as a function of reactor length is shown in Figure 15 based on the HeatPath pellet thermal conductivity about 8.81 W/m-K at the DRM reaction temperature .

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