WO2025001037A1 - Dispositif et procédé de production par oxydation d'oxyde d'éthylène basés sur un procédé en série en deux étapes d'éthylène - Google Patents

Dispositif et procédé de production par oxydation d'oxyde d'éthylène basés sur un procédé en série en deux étapes d'éthylène Download PDF

Info

Publication number
WO2025001037A1
WO2025001037A1 PCT/CN2024/070271 CN2024070271W WO2025001037A1 WO 2025001037 A1 WO2025001037 A1 WO 2025001037A1 CN 2024070271 W CN2024070271 W CN 2024070271W WO 2025001037 A1 WO2025001037 A1 WO 2025001037A1
Authority
WO
WIPO (PCT)
Prior art keywords
gas
ethylene
absorption
reaction
stripping
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2024/070271
Other languages
English (en)
Chinese (zh)
Inventor
王刚
卓润生
张信
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rezel Engineering Corp
Original Assignee
Rezel Engineering Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rezel Engineering Corp filed Critical Rezel Engineering Corp
Publication of WO2025001037A1 publication Critical patent/WO2025001037A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • 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
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • 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
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/06—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds in tube reactors; the solid particles being arranged in tubes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D301/00—Preparation of oxiranes
    • C07D301/02—Synthesis of the oxirane ring
    • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
    • C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
    • C07D301/08—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
    • C07D301/10—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase with catalysts containing silver or gold
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D301/00—Preparation of oxiranes
    • C07D301/32—Separation; Purification
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
    • C07D303/02—Compounds containing oxirane rings
    • C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms

Definitions

  • the invention relates to the technical field of petrochemical industry, and in particular to equipment and a process for producing ethylene oxide by two-step serial oxidation of ethylene.
  • Ethylene oxide is an important derivative of ethylene. As an intermediate product, it is mainly used in the production of ethylene glycol, amino alcohol, halogen alcohol, polyoxyethylene alkyl ether, ethylene glycol ether, non-ionic surfactant, etc. It can also be used in plasticizers, lubricants, plastics and rubber, etc. At present, industrial ethylene oxide is almost jointly built with ethylene glycol production equipment as the raw material of ethylene glycol equipment.
  • the chloroethanol method has a simple process flow and does not require high ethylene purity. However, it consumes a large amount of highly toxic chlorine during the production process; there are many side reactions, the unit consumption of ethylene is high; the equipment is severely corroded, the wastewater discharge is large, and the production cost is high. Therefore, it has been replaced by the ethylene direct oxidation method.
  • the air oxidation method uses purified air as the oxidant and adopts a main and auxiliary reactor design to achieve the oxidation of ethylene.
  • the main disadvantages of the air oxidation method are that the catalyst silver content is large, the selectivity is not high, the catalyst loading volume is large under the same processing scale, and the ethylene unit consumption is high; in addition, the air needs to be equipped with a purification system.
  • the pure oxygen oxidation method has a shorter process flow, lower silver content in the catalyst, and higher selectivity; the reaction temperature is low, which is conducive to extending the life of the catalyst; the ethylene content in the vented gas is lower than that of the air method, and the ethylene consumption is less.
  • the pure oxygen oxidation method is currently widely used in industrial production to produce ethylene oxide.
  • the reactor design and process flow of pure oxygen oxidation method for producing ethylene oxide are similar.
  • Silver-based catalysts are loaded into the tubes of fixed bed near-isothermal reactors, and then ethylene oxide is directly produced in one step. Then the ethylene oxide recovery and carbon dioxide removal processes are completed.
  • some catalysts have high selectivity and low raw material consumption, but low catalyst activity, large catalyst loading, and large reactor size; some have high catalyst activity, but low selectivity, large ethylene raw material consumption, and high production cost; and some catalysts have good selectivity and activity, but promoters need to be added to the reaction system, which increases the difficulty of handling subsequent processes.
  • the existing pure oxygen oxidation method adopts a one-step synthesis, and the isothermal tube oxidation reactor uses one or several in parallel. Due to the large heat release in the ethylene oxidation process, the explosion hazard of ethylene and oxygen mixture is Therefore, if the processing capacity is to be increased, reactors must be connected in parallel to expand production capacity.
  • the ethylene oxidation reaction is a highly exothermic reaction.
  • the initial stage of the reaction is controlled by kinetic reactions. It is necessary to increase the reaction temperature to increase the reaction rate in order to increase the conversion rate of the oxidation reaction. At the end of the reaction, it is controlled by thermodynamic equilibrium. Therefore, the ideal reaction state is that at the end of the isothermal tubular reactor, the reaction temperature is low, which is more conducive to the balance to advance in the direction of ethylene oxide production.
  • the terminal reaction temperature is low, and the explosion hazard of ethylene and oxygen mixing is small, so that in theory the oxygen concentration in the feed gas can be increased, the primary conversion rate can be improved, and the ethylene circulation ratio can be reduced, thereby reducing the load of the circulating compressor and achieving the purpose of energy saving and consumption reduction.
  • the existing one-step isothermal tubular reactor cannot achieve the requirement of low reaction terminal temperature.
  • US10858328B2 patent invented a method for producing ethylene oxide by oxidation, designed a water-cooled isothermal tube reactor, and loaded silver catalyst in the tube.
  • Raw materials ethylene, oxygen, and chloride inhibitor are mixed into the tube, and it is proposed to add an inhibitor to delay the corrosion of the reaction tube, and it is proposed to control the flow rate in the tube to be greater than 7m/s.
  • This invention patent only designed a water-cooled isothermal reactor, and the single-pass conversion rate was ⁇ 8%, so it still could not break the thermodynamic equilibrium limitation of the final stage of the ethylene oxidation reaction, and could not improve the ethylene primary conversion rate.
  • US2018/0370936A1 provides a method for reducing gaseous iodide impurities, especially alkyl iodide impurities, present in the circulating gas stream of an ethylene oxide production unit.
  • the ethylene oxidation reactor is designed as one, so, as in the above example, the primary conversion rate of ethylene cannot be improved.
  • CN205933707U proposes an ethylene oxide production device, in which two identical ethylene oxide reactors are arranged to operate in parallel, thereby increasing the circulating gas flow rate and flow velocity, and achieving the purpose of expanding the device capacity. Similarly, the parallel reactors cannot change the reaction temperature in the tubular bed layer, and cannot achieve the optimal operating state of the ethylene reaction kinetics and thermodynamic control.
  • CN112566888A proposes a method for producing ethylene oxide and ethylene glycol, wherein the ethylene oxidation reactor of the method is also a one-step single-unit oxidizer.
  • the present invention provides an ethylene oxide production equipment and process by two-step ethylene series oxidation method, by adopting a gas-gas isothermal tubular reactor and a water-gas isothermal tubular reactor for two-step series reaction, the two reactors take into account both the kinetic and thermodynamic states, improve the single-pass conversion rate, reduce the ethylene circulation ratio, reduce the energy consumption of the device, and improve the service life of the catalyst.
  • the invention discloses a device for producing ethylene oxide by two-step serial oxidation of ethylene, comprising a reaction unit, an ethylene oxide absorption and stripping unit, and a carbon dioxide absorption and stripping unit.
  • a gas-gas isothermal tubular reactor and a water-gas isothermal tubular reactor are arranged in series in the reaction unit.
  • the water-gas isothermal tubular reactor is used for the first step ethylene oxidation reaction
  • the gas-gas isothermal tubular reactor is used for the second step ethylene oxidation reaction.
  • the gas-gas isothermal tubular reactor comprises a gas-gas reactor shell and a gas-phase heat transfer tube bundle
  • the gas-gas reactor shell is provided with a shell-side air inlet port and a shell-side air outlet port
  • the gas-phase heat transfer tube bundle is provided with a lower air inlet spherical cavity and an upper air outlet spherical cavity
  • the gas-phase heat transfer tube bundle, the lower air inlet spherical cavity and the upper air outlet spherical cavity all adopt a spherical header structure
  • the spherical header structure makes it easy for maintenance personnel to enter the spherical cavity to inspect and plug leaks without removing the catalyst.
  • gas phase heat transfer tube bundle is provided with an arcuate bend
  • the gas phase transfer heat tube bundle adopts bow-shaped bends at both ends to eliminate thermal stress, avoiding the use of the commonly used straight tube bundle structure.
  • This bow-shaped bend tube bundle is a whole seamless steel tube structure without welding, has good flexibility, and the tube bundle can expand freely. It can eliminate stress by its own thermal expansion, ensuring that no stress acts on the air inlet and outlet spherical cavity.
  • the diameter of the arcuate curved tube bundle is selected according to the processing volume and heat transfer rate.
  • the gas phase heat transfer tube bundle adopts a high flux heat exchange tube, and the outer surface of the gas phase heat transfer tube bundle is provided with a metal porous layer;
  • the gas phase heat transfer tube bundle adopts high-flux heat exchange tubes. Since the heat transfer coefficient between gas-gas media is small, in order to improve the heat transfer efficiency, a high-flux heat exchange tube with enhanced tube heat transfer is adopted. By coating and sintering metal on the outer surface of the metal smooth tube, a metal porous layer is generated to achieve efficient heat transfer under a lower heat transfer temperature difference. It has the characteristics of enhanced boiling heat transfer and good scale inhibition performance, which is conducive to realizing the cascade utilization of energy and improving energy utilization rate.
  • the tube side of the gas-gas isothermal tube reactor is used to load a silver-based catalyst
  • the lower inlet ball cavity and the upper outlet ball cavity both adopt spherical structures.
  • the lower inlet ball cavity and the upper outlet ball cavity adopt a spherical structure, which has the best pressure bearing capacity compared with a flat tube plate or an elliptical structure.
  • the fresh feed gas in the tube side is heated and takes away a large amount of reaction heat of the second-step ethylene oxidation by-product. Since the temperature of the second-step oxidation reaction in the shell side is controlled at a relatively low level, the occurrence of tail burning is completely eliminated.
  • the tube side and shell side of the gas-gas isothermal tubular reactor only bear the pressure generated by the resistance drop of the reaction gas, which determines that the manufacturing cost of the gas-gas reactor is very low.
  • a steam drum is provided at the upper part of the shell side of the water-gas isothermal tube reactor, a saturated steam outlet pipe is provided at the top of the steam drum, a plurality of risers and downcomers are provided at the bottom of the steam drum, the risers are connected to the top of the reactor shell side, the downcomers are connected to the bottom of the reactor shell side, and the downcomers are provided with a steam mixer;
  • the water-gas isothermal tube reactor is provided with a natural circulation drum system in the shell side: the boiler water first enters the drum at the top of the shell side reactor.
  • a saturated steam outlet pipe is designed at the top of the drum, and a pressure regulating valve is installed on the pipe to adjust the pressure of steam produced by the drum.
  • the water-gas isothermal tube reactor adopts a tube sheet structure, and the upper tube sheet adopts a flexible tube sheet;
  • the water-gas isothermal tube reactor adopts a mature tube sheet structure, wherein the upper tube sheet adopts a flexible tube sheet to prevent thermal stress expansion caused by the temperature difference between the tube and shell.
  • the tube bundle of the water-gas isothermal tube reactor is made of seamless steel pipes and is arranged in a shell-side water bath;
  • a carbon steel pipe, an alloy steel pipe or a duplex stainless steel pipe may be selected.
  • a duplex stainless steel pipe is preferably selected.
  • the water-gas isothermal tube bundle also uses high-flux heat exchange tubes, and a metal sintering coating is applied to the outer layer of the tube bundle, which is particularly suitable for heat transfer conditions where the shell has phase change.
  • the diameter range of the tube bundle of the water-gas isothermal tube reactor is The length is 5000 ⁇ 8000mm.
  • tube ends of the tube bundle are provided with springs for supporting the catalyst and the magnetic balls;
  • a layer of grid is set on the lower flat tube plate.
  • the grid is easily deformed by pressure; by setting spring support, the space velocity of the catalyst bed can be increased, so as to reduce the catalyst loading.
  • the steam drum is a horizontal storage tank
  • the steam drum downcomer of the water-gas isothermal tubular reactor is provided with a steam mixer for heating the reactor during the start-up phase, thereby greatly reducing the reaction start-up time and saving raw material costs.
  • a pressure regulating valve is installed on the pipeline of the saturated steam outlet pipe.
  • the steam drum of the water-gas isothermal tubular reactor can accurately control the bed temperature by controlling the pressure of the produced medium-pressure steam.
  • the medium-pressure steam pressure ranges from 1.7 to 2.5 MPa, and the medium-pressure steam pressure of the present invention is 2.0 MPa.
  • the ethylene oxide absorption and stripping unit is provided with an ethylene oxide absorption tower, an ethylene oxide stripping tower and a quenched absorption liquid stripping tower, the ethylene oxide absorption tower is provided with a steam stripping section in the upper section and an ethylene glycol concentration section in the lower section, and the quenched absorption liquid stripping tower is used for stripping the ethylene glycol-rich alkali solution in the pre-washing section;
  • the main components of the reaction gas are ethylene, oxygen, ethylene oxide, carbon dioxide, methane, a small amount of ethylene glycol, aldehydes and acids, inhibitors and the like.
  • the ethylene oxide stripping tower is divided into two sections, the lower section is the ethylene glycol concentration section, where the rich liquid strips out the ethylene oxide and sends it to the upper tower.
  • the ethylene glycol solution is sent out as a product.
  • the upper section of the ethylene oxide stripping tower uses steam stripping, and all the ethylene oxide is stripped out and sent out as a product.
  • a quenching section is provided at the lower part of the ethylene oxide stripping tower, and an anti-blocking valve is provided in the quenching section;
  • the quenching absorption liquid stripping tower is used to strip the glycol-rich alkali solution in the pre-washing section to recover the ethylene oxide absorbed in the quenching section.
  • the glycol solution at the bottom of the quenching absorption liquid tower is sent out as a product.
  • the advantage of designing a quenching absorption liquid stripping tower is to recover ethylene oxide to the greatest extent, thereby reducing the energy consumption of the device.
  • Alkali liquor is used as circulating absorbent to absorb a small amount of acid and aldehyde impurities in the reactor outlet gas, which is convenient for controlling the purity of ethylene oxide products.
  • the advantage of designing a quenching section is that the purity of the ethylene oxide product is higher.
  • the packing layer of the main ethylene oxide absorption section is provided with two layers: lean liquid is used to absorb ethylene oxide, and the main component of the lean liquid is water. Ethylene oxide, ethylene glycol, etc. in the reaction gas are absorbed by the lean liquid to become rich liquid.
  • the remaining reaction gas mainly contains ethylene, oxygen, methane, and carbon dioxide, which is sent to the carbon dioxide absorption and stripping unit.
  • the carbon dioxide absorption and stripping unit comprises a circulating gas compressor, a carbon dioxide absorption tower and a carbon dioxide stripping tower connected in sequence, the carbon dioxide stripping tower is divided into two sections, the upper section is a flash section, and the lower section is a steam stripping section;
  • the carbon dioxide absorption tower internals adopt structured packing or floating valve tray structure
  • the internals of the carbon dioxide absorption tower adopt a structured packing structure.
  • the use process of the equipment includes the following:
  • Reaction stage fresh raw gas consisting of ethylene and oxygen enters the tube side of the gas-gas isothermal tubular reactor, and after being heated, it is sent to the tube side of the water-gas isothermal tubular reactor, where the first step of ethylene oxidation reaction occurs;
  • the gas after the first step reaction is collected by the lower pipe box and sent to the shell side of the gas-gas isothermal tube reactor for the second step oxidation reaction;
  • the temperature of the second step ethylene oxidation reaction is lower than the temperature of the first step ethylene oxidation reaction
  • the ethylene oxidation reaction is a highly exothermic reaction.
  • the initial stage of the reaction is controlled by kinetic reactions. It is necessary to increase the reaction temperature to increase the reaction rate in order to increase the conversion rate of the oxidation reaction.
  • At the end of the reaction it is controlled by thermodynamic equilibrium. Therefore, the ideal reaction state is that at the end of the isothermal tubular reactor, the reaction temperature is low, which is more conducive to the equilibrium moving toward the formation of ethylene oxide.
  • This application mainly achieves that the reaction temperature of the second step is lower than that of the first step by adding a second-step near-isothermal reactor. This not only takes into account the requirements of ethylene oxide for the reaction rate, but also can increase the thermodynamic equilibrium constant of the reaction and improve the single-pass conversion rate of ethylene. Thus, more products can be obtained under the same equipment size.
  • Ethylene oxide absorption and stripping stage After the second step of oxidation reaction is completed, the reaction gas flows out of the gas-gas isothermal tube reactor and enters the low-pressure steam boiler. After cooling, it enters the ethylene oxide absorption tower for pre-washing. The reactor enters the ethylene oxide main suction section, and the gas flowing out of the main suction section is sent to the carbon dioxide absorption and stripping unit;
  • Carbon dioxide absorption and stripping stage first, the circulating gas enters the circulating gas compressor for pressurization, and the pressurized circulating gas enters the carbon dioxide absorption tower.
  • the carbon dioxide absorption tower uses polyethylene glycol dimethyl ether as the absorption liquid. After passing through the carbon dioxide stripping tower after the absorption liquid, methane gas is flashed out, and low-pressure steam is used to analyze the carbon dioxide gas.
  • the carbon dioxide absorption tower uses polyethylene glycol dimethyl ether (NHD) as the absorption liquid.
  • NHD absorption liquid The chemical properties of NHD absorption liquid are good in temperature and thermal stability, non-toxicity, good corrosiveness, and good decarbonization effect. It is a better absorbent than potassium carbonate.
  • the carbon dioxide stripping tower is used to parse out the NHD rich liquid that has absorbed carbon dioxide.
  • the NHD rich liquid after parse is called lean liquid, which is recycled after cooling in the lean-rich liquid heat exchanger.
  • the first step of ethylene oxidation reaction conditions are: temperature 230-270°C, reaction pressure 1.0-3.0Mpa, catalyst bed space velocity selection range 4000-12000h - ;
  • the first step of ethylene oxidation reaction conditions are: temperature 240-260°C, reaction pressure 1.8-2.2Mpa, catalyst bed space velocity selection range 5000-9000h - ;
  • reaction conditions of the shell-side bed of the second step ethylene oxidation reaction are: temperature 190-220°C, reaction pressure 1.0-3.0Mpa, catalyst bed space velocity 2000-10000h - ;
  • reaction conditions of the shell-side bed of the second step ethylene oxidation reaction are: temperature 200-210° C., reaction pressure 1.8-2.2 MPa, catalyst bed space velocity 6000-8000 h - .
  • the absorption pressure of the main absorption section is 1.7-2.0 MPa, and the absorption temperature is 30-40°C.
  • the compressor outlet pressure is increased by 0.3 MPa compared with the inlet pressure
  • the carbon dioxide absorption tower absorption temperature control range is 20-40°C
  • the absorption pressure is 1.8-2.2 MPa.
  • the absorption liquid is selected from one or more of polyethylene glycol dimethyl ether, N-methyldiethanolamine or diethanolamine;
  • the absorption liquid is polyethylene glycol dimethyl ether, and the active component of polyethylene glycol dimethyl ether in the absorption liquid is ⁇ 99%, and the water content is ⁇ 1.0%.
  • a better amine salt is selected as the absorption liquid, which can be polyethylene glycol dimethyl ether (NHD), N-methyldiethanolamine (MDEA), diethanolamine (DEA) or a mixture thereof.
  • NHD is preferably used as the absorption liquid, because the chemical properties of the NHD absorption liquid are good in temperature and thermal stability, non-toxic, good in corrosiveness, and good in decarbonization effect.
  • the present invention adopts a two-step series reaction of a gas-gas isothermal tubular reactor and a water-gas isothermal tubular reactor, so that the two reactors take into account both the kinetic and thermodynamic states, improve the single-pass conversion rate, reduce the ethylene circulation ratio, reduce the energy consumption of the device, and increase the service life of the catalyst.
  • the existing ethylene oxidation isothermal fixed-bed reactor generally adopts a fixed tube sheet structure, which has a weak pressure bearing capacity, large thermal stress on the cold and hot sides, and is easy to cause tube
  • the gas-to-gas tube reactor adopts a collecting spherical cavity structure to solve the problem of large thermal stress between the tube sheet and the tube bundle in the isothermal tube reactor in the prior art, thus saving equipment cost.
  • the present invention is the first to use polyethylene glycol dimethyl ether (NHD) to replace potassium carbonate in the traditional ethylene oxide production process as the absorption liquid for CO2 in the circulating gas.
  • the polyethylene glycol dimethyl ether absorption liquid has good chemical properties such as temperature and thermal stability, is non-toxic, has good corrosiveness, and has a good decarbonization effect. It is a better absorbent than potassium carbonate.
  • FIG1 is a process flow chart of producing ethylene oxide by two-step tandem oxidation of ethylene according to the present invention
  • Fig. 2 is a schematic diagram of a gas-gas isothermal tube reactor
  • FIG. 3 is a schematic diagram of a water-gas isothermal tube reactor.
  • a process for producing ethylene oxide by two-step tandem oxidation of ethylene in which ethylene and oxygen undergo oxidation reaction in the presence of a silver-based catalyst to produce ethylene oxide is mainly divided into a reaction stage, an ethylene oxide absorption and stripping stage, and a carbon dioxide absorption and stripping stage.
  • the reactants mainly include ethylene oxide, ethylene, carbon dioxide, water, methane, trace aldehydes, and organic acids.
  • the present invention selects a silver catalyst for preparing ethylene oxide by ethylene oxidation disclosed in application number CN112206798B as a catalyst.
  • the silver catalyst is a composite carrier composed of ⁇ -silicon carbide and ⁇ -alumina, and contains 17wt% silver, 0.05wt% strontium, 0.5wt% magnesium, 0.65wt% fluorine, 0.05wt% cerium, 0.25wt% tin, 0.15wt% phosphorus, and 0.15wt% boron in mass percentage based on the total mass of the silver catalyst dry basis; the water absorption rate of the silver catalyst is 55%, the specific surface area is 0.91 square meters/gram, and the pore volume is 0.52 milliliters/gram, wherein the pores with a pore size of 5 to 30 microns account for 89%, and the pores with a pore size of ⁇ 30 microns account for 11%. Under this condition, the catalyst has excellent heat transfer, conduction, diffusion, and reaction activity, and is
  • Reaction stage The ethylene oxidation reaction is carried out in two steps. The first step is carried out at a relatively high temperature of 250°C, and the reaction site is the 3rd tube side of the water-gas isothermal tubular reactor; the second step is carried out at 210°C, and the reaction site is the 1st shell side of the gas-gas isothermal tubular reactor.
  • the fresh gas 24 containing ethylene and oxygen is mixed with the circulating gas 41, and the molar fraction of the mixed gas is as follows: ethylene 28%, oxygen 8%, carbon dioxide 5%, methane 50%, nitrogen 7%, argon 2%; a trace amount of 1,2-dichloroethane is also added to the raw gas as an inhibitor.
  • the mixed fresh gas is transported to the lower inlet spherical cavity 104 of the tube side of the gas-gas isothermal tubular reactor 1 through the fresh gas inlet 107.
  • the gas-gas isothermal tubular reactor 1 consists of a gas-gas reactor shell 101 and a tube bundle 102.
  • the two ends of the gas phase heat transfer tube bundle 105 adopt an arched bend and a spherical cavity structure, which has the best pressure resistance and flexibility.
  • the fresh gas 24 flows from bottom to top through the gas phase heat transfer tube bundle 105 and countercurrently exchanges heat with the synthesis gas after the first step oxidation reaction, and the temperature is heated from 40°C to 170°C. Then it is collected by the upper outlet spherical cavity 103 and discharged through the preheating gas outlet 108 pipe.
  • the preheated raw gas 32 is preheated again by the intermediate heat exchanger 2, and is preheated to 200°C before entering the water-gas isothermal tubular reactor 3 tube side for the first step oxidation reaction.
  • the synthesis gas 25 after the first step oxidation reaction flows from top to bottom through the shell side catalyst bed in the gas-gas isothermal tubular reactor 1 shell side and undergoes the second step oxidation reaction and finally leaves the reaction unit from the synthesis gas outlet 110 after the second step oxidation reaction. Since the fresh gas 24 in the tube takes heat, the temperature of the second step oxidation reaction bed is controlled. At 210°C, low temperature helps the reaction thermodynamic equilibrium constant move toward the production of ethylene oxide, thus breaking the conversion rate limit of the single-step oxidation reaction.
  • the gas-gas isothermal tubular reactor of this embodiment is also designed with a catalyst discharge port 106 on the shell side bed layer to facilitate the unloading of the catalyst on the shell side bed layer.
  • the diameter of the gas-gas reactor is 3000mm-4600mm, the length of the tube bundle is 5000mm-7000mm, and the diameter range of the tube bundle is
  • the shell side material is carbon steel, alloy steel or duplex steel, preferably carbon steel.
  • the gas phase heat transfer tube bundle 105 uses a high flux heat exchange tube, and the thickness of the porous layer of the high flux heat exchange tube is in the range of 0.1 mm to 0.3 mm, preferably 0.2 mm.
  • the porosity of the porous layer of the high flux heat exchange tube is between 30% and 70%, preferably 50%.
  • the metal powder used in the outer layer of the L-shaped bend tube bundle is mainly a Cu-based or Ni-containing Cu-based or Fe-based alloy powder with an average particle size of more than 70 ⁇ m, preferably a Fe-based alloy powder.
  • the preheated gas leaving the intermediate heat exchanger enters the water-gas isothermal tubular reactor 3 through the preheated raw gas inlet 304, and the synthesis gas 25 after the first oxidation reaction leaves through the synthesis gas outlet 305 after the first oxidation reaction.
  • the water-gas isothermal tubular reactor 3 is composed of a water-gas reactor shell side 301 and a heat exchange tube bundle 303, and the shell side is separated by a flexible tube sheet 302.
  • the flexible tube sheet is used to completely eliminate the thermal expansion caused by the temperature difference between the shell side and the tube side, prevent the reactor from leaking, and prevent the high-pressure water in the shell side from entering the catalyst bed in the tube side.
  • the silver-based catalyst is loaded in the water-gas isothermal tubular reactor 3 to provide a place for the first step of ethylene oxidation reaction.
  • About 70% of the oxidation reaction occurs in the water-gas isothermal tubular reactor 3, and the remaining 30% of the oxidation reaction occurs in the gas-gas isothermal tubular reactor 1.
  • the pressure of the medium-pressure saturated steam 28 of the water-gas reactor shell 301 and the medium-pressure steam drum 4 the temperature of the water side of the water-gas reactor shell 301 and the water heat extraction rate are adjusted to control the temperature of the bed in the tube.
  • the bed reaction temperature is controlled at 250°C.
  • the ethylene oxidation rate is controlled by the kinetic equation, the temperature is high, the reaction rate is large, the processing capacity is strong, and the required catalyst loading amount is small.
  • the synthesis gas 25 after the first step of the oxidation reaction is sent to the intermediate heat exchanger 2 to continue to recover the reaction heat.
  • the shell side 301 of the water-gas reactor, the medium-pressure steam drum 4, the downcomer 31, and the riser form a water closed-loop circulation.
  • the amount of boiler water added to the medium-pressure steam drum 4 is controlled by the flow regulating valve 29.
  • the boiler water enters the lower part of the water-gas isothermal tube reactor 3 from the boiler water downcomer port 307 through the natural circulation of thermosiphon.
  • the boiler water exchanges heat with the synthesis gas 25 after the first step oxidation reaction in the tube from bottom to top in countercurrent flow, absorbing 80% of the heat released by the reaction.
  • the boiler water itself changes from liquid phase to gas-liquid two-phase and finally circulates into the medium-pressure steam drum 4 from the boiler water riser port 306.
  • the upper layer of the medium-pressure steam drum 4 provides a space for separating the water vapor and liquid of the boiling boiler, and the by-product
  • the medium-pressure saturated steam is led out from the top of the drum.
  • a 6-pressure regulating valve is set on the saturated steam pipeline to control the steam pressure of the drum, which ranges from 1.7 to 2.5 MPa.
  • the medium-pressure steam pressure of the present invention is 2.0 MPa.
  • a start-up steam system is provided to preheat the water-gas heat exchanger during the start-up phase, thereby accelerating the start-up time and saving the consumption of ethylene oxygen.
  • the start-up steam system is composed of a venturi tube 5 and start-up steam 30.
  • the diameter of the water-gas reactor is 3200 mm to 4800 mm, preferably 4000 mm
  • the length of the tube bundle is 4000 mm to 8000 mm, preferably 6000 mm
  • the diameter range of the tube bundle is Best
  • the shell side material is preferably carbon steel, alloy steel or duplex steel, preferably carbon steel.
  • Ethylene oxide absorption and stripping stage In this embodiment, the temperature of the synthesis gas 26 after the second oxidation reaction reaches 200°C, and the one-way conversion rate of ethylene reaches 10% through the creative two-step reaction.
  • the molar percentage concentration of the synthesis gas 26 after the second oxidation reaction is as follows: ethylene 25.54%; oxygen 5.05%; carbon dioxide 6.42%; methane 48.52%; nitrogen 8%; argon 3%; water 1.2%; ethylene oxide 2.2%, and trace amounts of aldehydes and acids as byproducts.
  • the reaction gas temperature is still 200°C.
  • the low-pressure steam generator 7 In order to recover the waste heat of the reaction gas, it first enters the low-pressure steam generator 7, produces low-pressure steam (pressure 0.3 MPa) as a by-product and preheats the desalted water, and the reactor temperature drops to 75°C.
  • the rich liquid cooled in the reaction gas cooler 8 is then further cooled to 45°C and then enters the quenching section 9 of the ethylene oxide absorber.
  • the quenching section 9 of the ethylene oxide absorber adopts an anti-blocking valve and sodium hydroxide absorption liquid 33 as a circulating absorbent to absorb a small amount of acid and aldehyde impurities in the reactor outlet gas, so as to control the purity of the ethylene oxide product.
  • the quenching liquid 37 that has absorbed the acid and aldehyde is discharged from the bottom of the ethylene oxide absorption tower and sent to the quenching liquid stripping tower 17, where the dissolved trace ethylene oxide is recovered by low-pressure steam.
  • the quenching liquid stripping tower top gas 40 containing ethylene oxide is obtained at the top of the tower and recovered, and the bottom of the tower is ethylene glycol solution 35.
  • the quenching liquid stripping tower is a packed tower.
  • the gas at the top of the quenching section is sent to the ethylene oxide absorber absorption section 10 by the gas lift cap 12.
  • the function of the absorber is to absorb the ethylene oxide in the reaction gas and recover the unreacted ethylene and oxygen.
  • the ethylene oxide absorber absorption section 10 can usually adopt a packed tower or a plate tower.
  • absorption is favorable under high pressure and low temperature.
  • the operating pressure of the absorber is from 1.0 to 3.0 MPa, preferably 1.5 to 2.0 MPa and is determined by the operating pressure of the oxidation reactor; the absorption temperature range is 10 to 45°C, preferably 20 to 30°C.
  • water is used as the ethylene oxide absorption liquid, and the molar flow ratio of the absorption liquid to the reaction gas ranges from 0.2 to 3.0.
  • Ethylene, oxygen, carbon dioxide, methane, nitrogen, etc. that are not absorbed by the absorption liquid are discharged from the top of the main absorption section.
  • the carbon dioxide-rich recycle gas 27 is sent to the carbon dioxide absorption and stripping unit.
  • the ethylene oxide-rich absorption liquid 38 mainly contains ethylene oxide, water, a small amount of formaldehyde, acetic acid and other low-boiling impurities, which are discharged from the main absorption stage tower kettle, firstly recover the cold through the reactor cooler 8 and the stripping tower feed heater 16, and then are heated to 100° C. Then, they enter the ethylene oxide stripping tower steam direct stripping section 13.
  • the purpose of the ethylene oxide stripping tower is to recover ethylene oxide and regenerate the rich absorption liquid for recycling.
  • the steam direct stripping section 13 of the ethylene oxide stripping tower uses low-pressure steam to provide stripping heat, and ethylene oxide is obtained at the top of the tower. It is cooled into liquid form by the product cooler 18 and sent to the downstream reabsorption purification section for purification as ethylene oxide product liquid 36.
  • the lean absorption liquid 39 that is completely regenerated in the steam direct stripping section is discharged from the tower bottom and pressurized by the stripping tower lean liquid pump 15 and then divided into two paths. Most of the lean liquid is cooled by the stripping tower feed heater 16 and the lean liquid deep freezer 11 and then sent to the absorption tower for continued use.
  • the lean liquid deep freezer 11 is cooled by chilled water; a small part of the lean liquid is sent to the ethylene oxide stripping tower ethylene glycol concentration section 14 for continued stripping.
  • the top gas of this section returns to the steam direct stripping section 13 of the ethylene oxide stripping tower to replace part of the low-pressure steam, and the tower bottom is sent to the boundary area as the ethylene glycol-rich solution 34. From then on, a closed-loop ethylene oxide absorption and analytical recovery process is completed.
  • the carbon dioxide-rich circulating gas 27 first enters the circulating gas compressor 19 for pressurization to compensate for the pressure loss so that the circulating gas can enter the reactor again.
  • the carbon dioxide in the circulating gas will increase the inert gas in the system, affecting the reaction conversion rate and selectivity.
  • a carbon dioxide absorption tower 20 is designed.
  • polyethylene glycol dimethyl ether (NHD) is selected as the absorption liquid
  • the carbon dioxide absorption tower 20 adopts the form of packing.
  • the carbon dioxide-rich circulating gas 27 enters from the bottom of the tower and countercurrently exchanges gas and liquid with the NHD lean liquid 44 sprayed into the top of the tower. Here, most of the carbon dioxide in the circulating gas is absorbed.
  • the purified circulating gas 41 is mixed with the fresh gas 24 and enters the reactor to continue the reaction.
  • the NHD rich liquid 45 that absorbs carbon dioxide first passes through the NHD lean-rich liquid heat exchanger 23 to heat up, and finally enters the carbon dioxide stripping tower flash section 21.
  • the function of the carbon dioxide stripping tower flash section 21 is to recover useful gases such as methane and ethane absorbed by the NHD liquid. Since the solubility of methane and ethane is relatively low relative to carbon dioxide, the pressure of the flash section is controlled at 0.3Mpa.
  • the methane-rich gas 42 is discharged from the top of the flash section and sent to the downstream processing device.
  • the carbon dioxide-rich NHD liquid at the bottom of the carbon dioxide stripping tower flash section 21 enters the carbon dioxide stripping tower steam stripping section 22 by gravity.
  • the operating temperature of the steam stripping section of the carbon dioxide stripping tower is 110°C and the operating pressure is 0.15Mpa.
  • the tower bottom is stripped by steam, and the stripping can be indirectly stripped by a vertical thermosyphon heat exchanger or directly stripped by passing steam into the tower.
  • the preferred The indirect stripping method using a vertical thermosyphon heat exchanger is selected.
  • the carbon dioxide gas 43 stripped from the rich liquid is discharged from the top of the tower.
  • the bottom of the tower is a lean liquid that is substantially free of carbon dioxide, which is then cooled by the NHD lean-rich liquid heat exchanger 23 and recycled.
  • the equipment and process of ethylene two-step serial oxidation of ethylene oxide are the same as those in Example 1, except that the bed layer in the first step of the water-gas isothermal tubular reactor tube selects another more high-temperature resistant silver-based catalyst, the specific composition of which is as follows: 17wt% silver, 0.05wt% strontium, 0.45wt% magnesium, 0.56wt% fluorine, 0.07wt% cerium, 0.26wt% tin, 0.15wt% phosphorus, and 0.16wt% boron.
  • the catalyst has a water absorption rate of 51%, a specific surface area of 0.90 square meters/gram, and a pore volume of 0.50 milliliters/gram, wherein the pores with a pore size of 5 to 30 microns account for 85%, and the pores with a pore size of ⁇ 30 microns account for 15%. Since this catalyst is more resistant to high temperatures, the reaction temperature can be controlled at 260°C.
  • the shell-side bed of the second step gas-gas isothermal tubular reactor still uses the silver-based catalyst in Example 1, and the reaction temperature is controlled at 210° C. It is found that the total conversion rate of ethylene reaches 10%, and the selectivity is slightly reduced from 84% to 83.5%.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

L'invention concerne un dispositif et un procédé de production par oxydation d'oxyde d'éthylène basés sur un procédé en série en deux étapes d'éthylène, se rapportant au domaine technique de l'industrie pétrochimique. Un réacteur tubulaire isotherme gaz-gaz (1) et un réacteur tubulaire isotherme eau-gaz (3) sont raccordés en série dans une unité de réaction, le réacteur tubulaire isotherme eau-gaz (3) est conçu pour mettre en œuvre une réaction d'oxydation d'éthylène de première étape, et le réacteur tubulaire isotherme gaz-gaz (1) est conçu pour mettre en œuvre une réaction d'oxydation d'éthylène de seconde étape. Le procédé d'utilisation du dispositif comprend une étape de réaction, une étape d'absorption et de décapage d'oxyde d'éthylène, et une étape d'absorption et de décapage de dioxyde de carbone. Le procédé d'utilisation permet aux deux réacteurs de prendre en compte à la fois les états cinétiques et thermodynamiques, ce qui permet d'améliorer la conversion par passage, de réduire le taux de recyclage d'éthylène, de réduire la consommation d'énergie d'un appareil, et de prolonger la durée de vie d'un catalyseur.
PCT/CN2024/070271 2023-06-27 2024-01-03 Dispositif et procédé de production par oxydation d'oxyde d'éthylène basés sur un procédé en série en deux étapes d'éthylène Ceased WO2025001037A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202310767337.4 2023-06-27
CN202310767337.4A CN116764550B (zh) 2023-06-27 2023-06-27 一种乙烯两步串联法氧化生产环氧乙烷设备及其工艺

Publications (1)

Publication Number Publication Date
WO2025001037A1 true WO2025001037A1 (fr) 2025-01-02

Family

ID=87989210

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2024/070271 Ceased WO2025001037A1 (fr) 2023-06-27 2024-01-03 Dispositif et procédé de production par oxydation d'oxyde d'éthylène basés sur un procédé en série en deux étapes d'éthylène

Country Status (2)

Country Link
CN (1) CN116764550B (fr)
WO (1) WO2025001037A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116764550B (zh) * 2023-06-27 2025-10-21 上海润和盛建设备科技有限公司 一种乙烯两步串联法氧化生产环氧乙烷设备及其工艺

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0753536A (ja) * 1992-08-13 1995-02-28 Dow Chem Co:The 直接酸化エチレンオキシドプロセス
CN2764474Y (zh) * 2005-01-20 2006-03-15 中国寰球工程公司 一种用于环氧乙烷制备的列管式固定床反应器
CN103896883A (zh) * 2012-12-31 2014-07-02 天津市泰亨气体有限公司 一种采用空气氧化法生产环氧乙烷的方法
US20160052900A1 (en) * 2013-03-29 2016-02-25 Nippon Shokubai Co., Ltd. Method for producing ethylene oxide
CN111569787A (zh) * 2020-05-13 2020-08-25 万华化学集团股份有限公司 一种列管式固定床反应器及其在烯烃环氧化反应中的应用
CN211445577U (zh) * 2019-11-18 2020-09-08 三江乐天化工有限公司 一种环氧乙烷反应及反应气处理装置
CN113559675A (zh) * 2020-04-29 2021-10-29 北京诺维新材科技有限公司 一种环氧乙烷的分离方法与分离装置
CN116764550A (zh) * 2023-06-27 2023-09-19 上海润和盛建工程科技有限公司 一种乙烯两步串联法氧化生产环氧乙烷设备及其工艺

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2778878B2 (ja) * 1991-09-12 1998-07-23 株式会社日本触媒 エチレンオキシドの製造方法
US5849937A (en) * 1997-12-19 1998-12-15 Arco Chemical Technology, L.P. Epoxidation process using serially connected cascade of fixed bed reactors
CN2621805Y (zh) * 2003-06-03 2004-06-30 华东理工大学 管壳外冷—绝热复合式固定床催化反应器
DE102008025835A1 (de) * 2008-05-29 2009-12-03 Bayer Technology Services Gmbh Verfahren zur Herstellung von Ethylenoxid
WO2020072163A1 (fr) * 2018-10-02 2020-04-09 Exxonmobil Chemical Patents Inc. Conversion d'éthane en oxyde d'éthylène à l'aide de réacteurs en série
CN114436998A (zh) * 2020-11-05 2022-05-06 中国石油化工股份有限公司 一种乙烯环氧化开车方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0753536A (ja) * 1992-08-13 1995-02-28 Dow Chem Co:The 直接酸化エチレンオキシドプロセス
CN2764474Y (zh) * 2005-01-20 2006-03-15 中国寰球工程公司 一种用于环氧乙烷制备的列管式固定床反应器
CN103896883A (zh) * 2012-12-31 2014-07-02 天津市泰亨气体有限公司 一种采用空气氧化法生产环氧乙烷的方法
US20160052900A1 (en) * 2013-03-29 2016-02-25 Nippon Shokubai Co., Ltd. Method for producing ethylene oxide
CN211445577U (zh) * 2019-11-18 2020-09-08 三江乐天化工有限公司 一种环氧乙烷反应及反应气处理装置
CN113559675A (zh) * 2020-04-29 2021-10-29 北京诺维新材科技有限公司 一种环氧乙烷的分离方法与分离装置
CN111569787A (zh) * 2020-05-13 2020-08-25 万华化学集团股份有限公司 一种列管式固定床反应器及其在烯烃环氧化反应中的应用
CN116764550A (zh) * 2023-06-27 2023-09-19 上海润和盛建工程科技有限公司 一种乙烯两步串联法氧化生产环氧乙烷设备及其工艺

Also Published As

Publication number Publication date
CN116764550A (zh) 2023-09-19
CN116764550B (zh) 2025-10-21

Similar Documents

Publication Publication Date Title
CN112678770B (zh) 一种采用psa尾气催化燃烧供热的甲醇、水制氢装置
US10017438B2 (en) Method and device system for producing dimethyl oxalate through carbonylation of industrial synthesis gas and producing ethylene glycol through dimethyl oxalate hydrogenation
EP0181313B1 (fr) Récupération de chaleur d'acide sulfurique concentré
JP2778878B2 (ja) エチレンオキシドの製造方法
CN103232321B (zh) 一种甲醇合成工艺
EP3199231A1 (fr) Réacteur de grande taille et dispositif et procédé correspondants
CN101429098B (zh) 一种由co、co2和h2合成甲醇的方法
JPH0459243B2 (fr)
EP4197993A1 (fr) Installation et procédé intégrés pour la production de méthanol à partir de dioxyde de carbone et d'hydrogène
CN115745794A (zh) 乙烯法醋酸乙烯生产工艺及装置
CN204917951U (zh) 去除粗煤气中co的等温变换系统
CN205188177U (zh) 一种合成气制乙二醇工艺中亚硝酸甲酯的再生装置系统
CN116764550B (zh) 一种乙烯两步串联法氧化生产环氧乙烷设备及其工艺
CN117720397A (zh) 一种二氧化碳催化加氢制甲醇的工艺和装置
JPS62167207A (ja) 濃硫酸の製造方法及びこれに使用する三酸化硫黄吸収装置
CN105008327B (zh) 尿素设备改造方法
CN214456890U (zh) 一种串联式双氨合成塔
CN202808648U (zh) 甲醇合成系统
JP2023532828A (ja) イソプロピルアルコールの製造方法
CN220478148U (zh) 一种酯化法环己酮装置内氢气综合利用系统
PL136300B1 (en) Method of isolating concentrated aqueous solution of ethylene oxide
CN204412040U (zh) 一种组合式天然气净化厂低浓度酸气处理装置
CN112209408A (zh) 一种串联式双氨合成塔
CN115920784B (zh) 一种dmo生产系统和开停车方法
CN201537408U (zh) 一种用于天然气制氢的净化处理塔

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24829700

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE