System and method for synergistic carbon dioxide capture and in-situ conversion with low temperature plasma coupled bifunctional materials

Abstract

The application discloses a system for synergistic carbon dioxide capture and in-situ conversion of low-temperature plasma coupled with bifunctional materials, which achieves the synergistic effect of low-temperature plasma and adsorption and catalysis bifunctional materials, thereby realizing direct capture and activation of CO2 and in-situ catalytic conversion of CO2 into high-value-added chemicals under mild conditions, avoiding desorption by heating and high-temperature CO2 conversion under severe conditions, and solving the bottleneck that the prior art is difficult to directly capture and in-situ efficiently convert CO2 in low-temperature flue gas under mild conditions. The application further discloses a method for carbon dioxide capture and in-situ conversion using the system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon capture and utilization, and particularly relates to a system and method for low-temperature plasma coupling with bifunctional materials for synergistic carbon dioxide capture and in-situ conversion. BACKGROUND

[0002] Under the carbon neutralization target, CO2 capture and utilization and storage (CCUS) is an important technology for ensuring sustainable large-scale low-carbon utilization of traditional fossil energy. However, the traditional CCUS technology has problems of high energy consumption, high cost, low timeliness, etc., which greatly hinders its popularization and application. In recent years, a new technology of CO2 capture and in-situ conversion has attracted close attention. According to the temperature range of flue gas from the emission source and the target carbon-based product, the technology designs a capture and catalytic conversion bifunctional material, realizes CO2 capture and in-situ conversion in the same reactor, and regenerates the bifunctional material after conversion to enter the cycle of carbon capture and in-situ conversion again, thereby avoiding the process of desorption, compression and transportation of captured CO2 in the conventional CCUS technology, and reducing the system energy consumption of waste carbon resource conversion and utilization. However, due to the thermodynamic stability of CO2 molecules, CO2 conversion often needs to inject a large amount of energy to activate and convert under harsh conditions such as high temperature and high pressure. Therefore, at present, domestic and foreign researches mainly focus on the mid-high temperature CO2 capture and in-situ conversion to produce simple C1 chemicals such as methane and synthesis gas. It is worth noting that most of the industrial flue gas has been equipped with a heat exchange system to fully utilize waste heat and save energy. After denitrification and desulfurization, the flue gas is usually low in temperature (<150℃) and low in CO2 concentration. There is a temperature mismatching problem between the low-temperature CO2 capture and the high-temperature in-situ conversion process. The description of Chinese patent application CN112569739A discloses a system for high-temperature carbon dioxide capture and in-situ thermal catalytic conversion into synthesis gas, which is suitable for direct carbon capture and conversion into synthesis gas from high-temperature flue gas (600-800℃), but is not suitable for carbon capture-conversion of low-temperature flue gas. Therefore, how to realize low-concentration CO2 capture and in-situ efficient conversion into high-value-added chemicals such as methane, methanol and olefins under low temperature and atmospheric pressure conditions is an important research direction to break through the bottleneck of high energy consumption and high cost of CCUS technology.

[0003] The low-temperature CO2 catalytic conversion technology mainly includes photocatalysis and electrocatalysis. The photocatalysis technology can directly use sunlight as energy, and has mild reaction conditions. However, the light energy utilization rate, conversion efficiency and product selectivity of the technology are low due to low electron production efficiency and insufficient proton supply. The energy utilization rate of the electrocatalysis technology is high. However, the conversion efficiency and product selectivity are low due to the competition between CO2 reduction reaction and hydrogen evolution reaction, and the low solubility of CO2 in water. The emerging low-temperature CO2 plasma catalytic conversion technology can promote the activation of CO2 under mild conditions due to the low temperature and high electron energy (the temperature can reach several to tens of thousands of K) of the non-thermal plasma, and realize the conversion of CO2 by coupling with the catalyst. Therefore, the low-temperature plasma catalytic CO2 conversion method with higher conversion rate, more diverse conversion products and higher selectivity of target products in the conversion products still needs to be developed. SUMMARY

[0004] In view of the characteristics of low-temperature flue gas, the system for synergistic carbon dioxide capture and in-situ conversion of low-temperature plasma coupled with bifunctional material is proposed. By coupling low-temperature plasma with bifunctional material with adsorption and catalytic activity sites, the synergistic effect of the two is achieved, so that the low-concentration CO2 is directly captured and activated and in-situ catalytically converted into high-value chemicals under mild conditions, avoiding high-temperature CO2 conversion conditions, to solve the bottleneck that the prior art cannot directly capture and in-situ efficiently convert CO2 from low-temperature flue gas under mild conditions.

[0005] In one aspect, the system for synergistic carbon dioxide capture and in-situ conversion of low-temperature plasma coupled with bifunctional material is provided, comprising a pretreatment unit, a plasma generation unit, a carbon capture-conversion integrated unit and a separation-purification unit, characterized in that the carbon dioxide is carbon dioxide in air or industrial flue gas; the carbon capture-conversion integrated unit is filled with bifunctional material, wherein the bifunctional material comprises an adsorption component and a catalytic component; the reaction temperature of the carbon capture-conversion integrated unit is 0-210 DEG C, and the reaction is an adsorption reaction or a conversion reaction.

[0006] Preferably, the reaction temperature of the carbon capture-conversion integrated unit is 25-200 DEG C.

[0007] Preferably, the adsorption reaction temperature of the carbon capture-conversion integrated unit is 15-160 DEG C.

[0008] Preferably, the conversion reaction temperature of the carbon capture-conversion integrated unit is 15-210 DEG C.

[0009] Preferably, the adsorption reaction temperature of the carbon capture-conversion integrated unit is the same as the conversion reaction temperature.

[0010] Preferably, the adsorption reaction temperature of the carbon capture-conversion integrated unit is different from the conversion reaction temperature.

[0011] Preferably, the reaction pressure of the carbon capture-conversion integrated unit is 0.01-5 MPa; more preferably, the reaction pressure of the carbon capture-conversion integrated unit is 0.1 MPa.

[0012] Preferably, the carbon dioxide content in the air or industrial flue gas is 0.01-90 vol%; more preferably, the carbon dioxide content in the air or industrial flue gas is 0.04-30 vol%; more preferably, the carbon dioxide content in the air or industrial flue gas is 0.04-20 vol%.

[0013] Preferably, the temperature of the air or industrial flue gas is 0-200℃; more preferably, the temperature of the air or industrial flue gas is 15-160℃.

[0014] In one or more embodiments, the adsorption component is selected from the group consisting of one or more of combinations of hydrotalcite, zeolite, activated carbon, modified ion resin, calcium oxide, magnesium oxide, solid loaded amino, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide; the catalytic component is selected from the group consisting of one or more of combinations of metals or metal oxides of iron, nickel, cobalt, copper, ruthenium, platinum, palladium, rhodium, zinc; the mass percentage of the adsorption component in the bifunctional material is 0.1-99 wt%, and the mass percentage of the catalytic component in the bifunctional material is 0.1-60 wt%.

[0015] Preferably, the mass percentage of the adsorption component in the bifunctional material is 40-97 wt%, and the mass percentage of the catalytic component in the bifunctional material is 3-50 wt%.

[0016] In one or more embodiments, the bifunctional material further comprises a promoter component, and the promoter component is selected from the group consisting of one or more of combinations of cerium, potassium, sodium, phosphorus, nitrogen; the mass percentage of the promoter component in the bifunctional material is 0-20 wt%.

[0017] Preferably, the mass percentage of the promoter component in the bifunctional material is 0-15 wt%.

[0018] In one or more embodiments, the pretreatment unit comprises a dust removal purification device and a temperature control module; the pretreatment unit is connected to the carbon capture-conversion integrated unit.

[0019] The plasma generation unit comprises a high-frequency alternating current power supply, a voltage controller, an oscilloscope and a high-voltage electrode, wherein the high-voltage electrode is embedded inside the plasma reactor of the carbon capture-conversion integrated unit.

[0020] The carbon capture-conversion integrated unit comprises a plasma reactor, a program flow control valve and a temperature control module; wherein the plasma reactor is a multi-stage parallel plasma fixed bed reactor or a circulating plasma fluidized bed reactor; the plasma reactor is internally filled with a bifunctional material;

[0021] The separation-purification unit comprises a condensing device and a separation device, wherein the separation device is a gas-liquid separation device or a pressure swing adsorption device; the product separation-purification unit is connected with the carbon capture-conversion integrated unit.

[0022] Preferably, the pretreatment unit, the carbon capture-conversion integrated unit and the separation-purification unit are sequentially connected.

[0023] Preferably, the plasma type of the plasma generation unit comprises a combination of one or more of arc discharge, dielectric barrier discharge, glow discharge plasma, etc.

[0024] Preferably, the plasma generation unit is composed of a high-voltage electrode, a grounding electrode and an insulating medium, the high-voltage electrode is embedded in the plasma reactor inside the carbon capture-conversion integrated unit, the outside of the plasma reactor is used as the grounding electrode with any one of stainless steel, aluminum, copper, molybdenum, tungsten, iron, and the insulating medium is selected from quartz, glass, mica or ceramic.

[0025] Preferably, the power of the high-voltage power supply is 10W-5000W, and the frequency of the plasma can be adjusted in the range of 50Hz-1MHz.

[0026] Preferably, the shape of the high-voltage electrode in the plasma generation unit is a combination of one or more of blades, rods, arcs, discs; the material of the high-voltage electrode is a combination of one or more of copper, iron, alloy, graphite and stainless steel.

[0027] In another aspect, the present application provides a method for carbon dioxide capture and in-situ conversion using the system as described in any of the embodiments herein, characterized in that, in the method, the carbon capture-conversion integrated unit captures and converts carbon dioxide in air or industrial flue gas under the action of plasma and reducing gas, and specifically comprises the following steps:

[0028] S1: Plasma-induced activation of bifunctional material: reducing gas is introduced into the plasma reactor filled with bifunctional material in the carbon capture-conversion integrated unit, and under the action of plasma, active hydroxyl groups are generated on the surface of the bifunctional material, which facilitates the efficient adsorption of low-concentration carbon dioxide in air or industrial flue gas, and at the same time, the metal catalytic sites in the bifunctional material are induced to reduce under low temperature conditions;

[0029] S2: Air / gas pretreatment: The air or industrial flue gas input into the system is first subjected to a dust removal and purification device in the pretreatment unit, and the fine particulate dust in the air or industrial flue gas is removed by a combination of electrostatic dust removal and mechanical dust removal. If the temperature of the air or industrial flue gas is different from the adsorption reaction temperature of the plasma reactor, the temperature control module in the pretreatment unit is turned on to make the temperature of the air or industrial flue gas reach the adsorption reaction temperature.

[0030] S3: Low-temperature adsorption capture: The pretreated air or industrial flue gas is introduced into the plasma reactor, and after adsorption treatment by the bifunctional material, the carbon dioxide is captured at low temperature. The decarburized air or industrial flue gas after adsorption treatment is directly discharged.

[0031] S4: In-situ conversion of adsorbed carbon dioxide: The raw gas is introduced into the plasma reactor through the control valve, and under the catalysis of the bifunctional material and the action of the plasma, the captured carbon dioxide is converted in-situ to generate product gas containing target products.

[0032] S5: Product gas separation and purification: The product gas enters the condensing device and separation device in the separation-purification unit in turn, the separated target products are collected, and the separated raw gas that is not completely reacted is re-introduced into the raw gas pipeline through the control valve for recycling.

[0033] In one or more embodiments, the raw gas is selected from a combination of one or more of hydrogen, water vapor, ammonia, carbon monoxide, methane, and ethane.

[0034] In one or more embodiments, in step S1, the reducing gas is selected from a combination of one or more of hydrogen, ammonia, carbon monoxide, methane, and ethane, and the reducing gas is heated to the adsorption reaction temperature by a preheater before being introduced into the plasma reactor; the time for inducing and activating the bifunctional material is 1 min to 10 h.

[0035] Preferably, in step S1, the time for inducing and activating the bifunctional material is 4 min to 7 h.

[0036] In one or more embodiments, in step S2, the volume space velocity of the air or industrial flue gas introduced into the plasma reactor is 10 to 10000 h -1 .

[0037] In one or more embodiments, in step S3, the volume space velocity of the raw gas introduced into the plasma reactor is 100 to 10000 h -1 ; the target product is selected from carbon monoxide, synthesis gas, methane, methanol, or olefin.

[0038] In one or more embodiments, when the target product is methanol in step S3, the separation device in step S4 is a gas-liquid separation device; or, when the target product is selected from carbon monoxide, syngas, methane or olefin in step S3, the separation device in step S4 is a pressure swing adsorption device.

[0039] In one or more embodiments, the plasma reactor is a multi-stage parallel plasma fixed-bed reactor, wherein the multi-stage parallel plasma fixed-bed reactor is a double parallel plasma fixed-bed reactor; when the carbon dioxide adsorption capacity of the bifunctional material in one of the reactors reaches saturation, the plasma generation unit corresponding to the reactor is started, and the raw material gas is introduced into the reactor through a control valve for in-situ conversion, while switching to introducing air or industrial flue gas into the other reactor for carbon dioxide adsorption.

[0040] In one or more embodiments, the plasma reactor is a circulating plasma fluidized bed reactor, comprising an adsorption reactor and a conversion reactor; when the carbon dioxide adsorption capacity of the bifunctional material in the adsorption reactor reaches saturation, the bifunctional material in the adsorption reactor and the conversion reactor is separated using a cyclone separator, and then introduced into the two reactors respectively through pipelines to realize the circulation of the bifunctional material in the two reactors. In another aspect, the present application provides a use of a system as described in any one of the embodiments herein in carbon dioxide capture and in-situ conversion.

[0041] The system and method for low-temperature plasma coupled with bifunctional material to synergize carbon dioxide capture and in-situ conversion provided by the application, on the one hand, the carbon capture-conversion integrated unit is filled with adsorption / catalysis bifunctional material with high carbon dioxide adsorption capacity and high catalytic activity, the catalytic activity component and the catalytic component in the material are highly dispersed on the porous structure adsorption component substrate, so that the CO2 can be effectively combined with the adjacent metal catalytic active sites after being adsorbed and fixed, the catalytic activity of the reaction is greatly improved, and the CO2 conversion efficiency is improved, and the porous structure makes the catalytic active sites fully exposed, which is also beneficial to the diffusion of reactants and products, so that the carbon dioxide capture and in-situ conversion at the same temperature are realized; on the other hand, the plasma and the bifunctional material are coupled, the high-energy electrons in the low-temperature plasma can activate the reducing gas introduced into the catalytic active center of the bifunctional material adsorption-catalysis reaction interface through ionization, excitation and dissociation to produce active hydrogen species, and the hydrogen species produced by the metal catalytic active site directly reacts with the adjacent adsorbed CO2 molecules through hydrogen overflow, so that the target product can be generated with high conversion rate and high selectivity under low temperature and normal pressure. The application can avoid the high temperature and high pressure harsh conditions of conventional production of methanol and olefins, the high temperature demand of production of synthesis gas and methane, and the temperature difference contradiction between the low-temperature air or industrial flue gas carbon capture and the high-temperature carbon conversion process, so that the energy consumption is greatly reduced.

[0042] In addition, the system and equipment provided in the application have low cost, short process flow, simple operation and easy control, and can solve the problems of high cost in the CO2 capture, separation, purification and transportation process and low efficiency and high energy consumption in the CO2 conversion, and can also produce high value-added products, thereby providing a technical scheme for low-temperature flue gas CO2 capture and utilization in the industrial field. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The system process flow chart for low-temperature plasma coupled with bifunctional material to synergize carbon dioxide capture and in-situ conversion.

[0044] Figure 2 The multi-stage fixed bed parallel process flow chart for the system for low-temperature plasma coupled with bifunctional material to synergize carbon dioxide capture and in-situ conversion.

[0045] Figure 3 The circulating fluidized bed process flow chart for the system for low-temperature plasma coupled with bifunctional material to synergize carbon dioxide capture and in-situ conversion. DETAILED DESCRIPTION

[0046] In order to make the present application clearer, the present application will be further described below in conjunction with preferred embodiments. It should be understood that the specific descriptions given below are illustrative and non-limiting, and should not be used to limit the scope of protection of the present application.

[0047] The "low temperature" in the present application refers to a relatively low temperature compared with the temperature of 600-800℃ of the conventional carbon dioxide capture technology, and can be specifically understood as a temperature in the range of 0-210℃.

[0048] The "dual-functional material" in the present application is a material having the functions of adsorbing CO2 and catalyzing the conversion of CO2 into target products, which includes an adsorption component, a catalytic component, and can further include a cocatalytic component. The adsorption component can be selected from one or more combinations of hydrotalcite, zeolite, activated carbon, modified ion resin, calcium oxide, magnesium oxide, solid-supported amino, sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide; the mass percentage of the adsorption component in the dual-functional material is 0.1-99wt%. The catalytic active component can be selected from one or more combinations of metals or metal oxides of iron, nickel, cobalt, copper, ruthenium, platinum, palladium, rhodium, and zinc; the mass percentage of the catalytic component in the dual-functional material is 0.1-60wt%. The cocatalytic component can be selected from one or more combinations of cerium, potassium, sodium, phosphorus, and nitrogen; the mass percentage of the cocatalytic component in the dual-functional material is 0-20wt%.

[0049] In the present application, the "dual-functional material", "adsorption component", or "catalytic component" is determined for "CO2 adsorption amount" by using a CO2 infrared analyzer before being used for CO2 adsorption and in-situ conversion in air or industrial flue gas. The calculation of the CO2 adsorption amount adopts the CO2 infrared analyzer to detect the outlet concentration of decarbonized flue gas, and is calculated by formula (I):

[0050]

[0051] wherein is the molar flow of CO2 in the inlet air or flue gas, is the molar flow of CO2 in the outlet gas, t s is the duration of the capture process, and M0 is the mass of the loaded sample.

[0052] Example 1: Preparation of dual-functional material

[0053] Preparation or acquisition of adsorption component:

[0054] Preparation method of hydrotalcite (LDH): taking MgAl-LDH as an example, 10.0g MgCl2·6H2O, 4.0g AlCl3·6H2O (Mg / Al molar ratio is 3) and 3.94g urea are dissolved in 30mL deionized water, after stirring uniformly, it is transferred into a 100mL polytetrafluoroethylene liner and sealed, and then hydrothermal treatment is carried out at 150℃ for 10h; after the hydrothermal treatment is completed, the liquid is cooled to room temperature, filtration is carried out, the obtained white precipitate is washed with deionized water for multiple times, and then drying is carried out at 70℃ for 12h, so that MgAl-LDH is obtained.

[0055] Obtaining of other adsorption components: zeolite, activated carbon, modified ion resin, calcium oxide, magnesium oxide, solid loaded amino, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide and other adsorption components can be obtained by market purchase.

[0056] General preparation method of bifunctional material: the bifunctional material in the application is prepared by impregnation method, that is, the adsorption component is used as a carrier, a salt solution of the corresponding content of the catalytic component (and the cocatalyst component) is impregnated, and then filtration, washing and calcination are carried out, so that the corresponding adsorption-carrier bifunctional material is obtained, and granulation is carried out at 40-60 meshes.

[0057] Preparation of NiCo / K / LDH bifunctional material:

[0058] According to the target metal loading mass fraction, 2.72 g of the catalytic component corresponding to nickel nitrate, cobalt nitrate and 0.23 g of the co-catalytic component corresponding to potassium nitrate were dissolved in 100 mL of aqueous solution and stirred uniformly; then 7.05 g of the LDH adsorption carrier was added to the above mixed solution and stirred, the mixed solution was raised to 70°C, then 5 mL of ammonia water was added and stirred for 3 h, then filtered, the obtained solid was washed with water for 2-3 times, and dried at 80°C overnight; after the solid was air calcined at 450°C for 3 h (the heating rate of the calcination equipment was 5°C / min), 10 g of the NiCo / K / LDH bifunctional material was obtained, and was granulated to 40-60 mesh.

[0059] Preparation of RuPt / P / zeolite (or RuPd / P / zeolite) bifunctional material:

[0060] According to the target metal loading mass fraction, 1.44 g of the catalytic component corresponding to ruthenium nitrate, platinum nitrate (or palladium chloride) and 0.54 g of the co-catalytic component corresponding to a phosphorus-containing salt such as potassium phosphate or sodium phosphate were dissolved in 200 mL of aqueous solution and stirred uniformly; then 8.02 g of the zeolite adsorption carrier was dispersed into the above mixed solution, 2 mL of ammonia water was added at 100°C and stirred for 12 h, then filtered, the obtained solid was washed with water for 2-3 times, dried at 80°C overnight, and air calcined at 300°C for 5 h (the heating rate was 5°C / min) to obtain 10 g of the RuPt / P / zeolite (or RuPd / P / zeolite) bifunctional material, which was granulated to 40-60 mesh.

[0061] Preparation of Cu / Ce / CaO bifunctional material:

[0062] According to the target metal loading mass fraction, 0.31 g of the catalytic component corresponding to copper sulfate and the co-catalytic component corresponding to cerium nitrate was dissolved in 150 mL of aqueous solution and stirred uniformly; then 9.64 g of the porous calcium oxide adsorption carrier was dispersed into the above mixed solution, 4 mL of ammonia water was added at 90°C and stirred for 6 h, then filtered, the obtained solid was washed with water for 2-3 times, and dried at 80°C overnight; after the solid was air calcined at 450°C for 5 h (the heating rate of the calcination equipment was 5°C / min), 10 g of the Cu / Ce / CaO bifunctional material was obtained, and was granulated to 40-60 mesh.

[0063] Preparation of FeCo / K2CO3 / zeolite (or FeCo / Na2CO3 / zeolite) bifunctional material:

[0064] According to the target metal loading mass fraction, 4.02 g of the catalytic component corresponding to iron chloride, cobalt chloride, potassium carbonate or sodium carbonate (dissolved in 130 mL of water solution and stirred uniformly; then 4.02 g of zeolite adsorbent carrier was dispersed into the above mixed solution, 5 mL of ammonia water was added at 50°C, and stirring impregnation was carried out for 9 h, then filtration was carried out, the obtained solid was washed with water for 2-3 times, and drying was carried out at 80°C overnight; 10 g of FeCo / K2CO3 / zeolite (or FeCo / Na2CO3 / zeolite) bifunctional material was obtained after air calcination at 400°C for 5 h (the temperature rising rate was 5°C / min), and granulation was carried out at 40-60 mesh.

[0065] Preparation of FeNi / N / activated carbon (or FeNi / N / MgO) bifunctional material:

[0066] According to the target metal loading mass fraction, 3.0 g of the catalytic component corresponding to iron nitrate, nickel nitrate, 1.0 g of the catalytic component corresponding to urea was dissolved in 180 mL of water solution and stirred uniformly; then 6.0 g of activated carbon (or magnesium oxide) adsorbent carrier was dispersed into the above mixed solution, 2 mL of ammonia water was added at 60°C, and stirring impregnation was carried out for 4 h, then filtration was carried out, the obtained solid was washed with water for 2-3 times, and drying was carried out at 80°C overnight; 10 g of FeNi / N / activated carbon (or FeNi / N / MgO) bifunctional material was obtained after air calcination of the solid at 400°C for 3 h (the temperature rising rate of the calcination equipment was 5°C / min), and granulation was carried out at 40-60 mesh.

[0067] Preparation of RhNi / Na / ionic resin bifunctional material:

[0068] According to the target metal loading mass fraction, 5.0 g of the catalytic component corresponding to rhodium chloride and nickel chloride, 0.05 g of the catalytic component sodium chloride was dissolved in 100 mL of water solution and stirred uniformly; then 4.95 g of ionic resin adsorbent carrier was dispersed into the above mixed solution, 5 mL of ammonia water was added at 25°C, and stirring impregnation was carried out for 12 h, then filtration was carried out, the obtained solid was washed with water for 2-3 times, and drying was carried out at 80°C overnight; 10 g of RhNi / Na / ionic resin bifunctional material was obtained after air calcination of the solid at 300°C for 3 h (the temperature rising rate of the calcination equipment was 5°C / min), and granulation was carried out at 40-60 mesh.

[0069] Preparation of CuZn / Ce / NH2-zeolite (amino grafted zeolite) bifunctional material:

[0070] According to the target load metal mass fraction, 2.81 g of copper nitrate, zinc chloride corresponding to the catalytic component, 1.5 g of cerium nitrate corresponding to the co-catalytic component is dissolved in 200 mL of aqueous solution and stirred uniformly; then 5.69 g of ion resin adsorption carrier is dispersed into the above mixed solution, 2 mL of ammonia water is added at 25℃, and stirring is carried out for 8 h, then filtration is carried out, the solid obtained by filtration is washed with water for 2-3 times, and drying is carried out at 80℃ overnight; after air calcination of the solid at 200℃ for 3 h (the heating rate of the calcination equipment is 5℃ / min), 10 g of CuZn / Ce / NH2-molecular sieve bifunctional material is obtained, and granulation is carried out at 40-60 mesh.

[0071] Co / Na-K / activated carbon bifunctional material preparation:

[0072] According to the target load metal mass fraction, 2.81 g of copper nitrate, zinc chloride corresponding to the catalytic component, 1.5 g of cerium nitrate corresponding to the co-catalytic component is dissolved in 200 mL of aqueous solution and stirred uniformly; then 5.69 g of ion resin adsorption carrier is dispersed into the above mixed solution, 2 mL of ammonia water is added at 25℃, and stirring is carried out for 8 h, then filtration is carried out, the solid obtained by filtration is washed with water for 2-3 times, and drying is carried out at 80℃ overnight; after air calcination of the solid at 200℃ for 3 h (the heating rate of the calcination equipment is 5℃ / min), 10 g of CuZn / Ce / NH2-molecular sieve bifunctional material is obtained, and granulation is carried out at 40-60 mesh.

[0073] Example 2: System and process flow of low-temperature plasma coupled bifunctional material synergistic carbon dioxide capture and in-situ conversion

[0074] As shown in Figure 1 The system of low-temperature plasma coupled bifunctional material synergistic carbon dioxide capture and in-situ conversion of the present embodiment includes a pretreatment unit 1, a plasma generation unit 2, a carbon capture-conversion integrated unit 3 and a separation-purification unit 4, wherein:

[0075] The pretreatment unit 1 includes a dust removal purification device and a temperature control module, which is used for pretreating air or industrial flue gas; the dust removal purification device is used for purifying fine particle dust in air or industrial flue gas, deeply removing fine particles to avoid clogging the reactor in the subsequent carbon capture-conversion integrated unit or affecting the catalytic performance of the bifunctional material, for example, one or a combination of electrostatic precipitation and mechanical dust removal equipment can be used; the temperature control module is used for temperature adjustment of air or industrial flue gas to meet the requirements of adsorption reaction temperature and conversion reaction temperature. The pretreatment unit 1 is connected with the carbon capture-conversion integrated unit 3, and the pretreated air or industrial flue gas directly enters the carbon capture-conversion integrated unit 3.

[0076] The plasma generating unit 2 comprises a high-frequency alternating current power supply, a voltage controller, an oscilloscope and a high-voltage electrode for generating plasma required for adsorption and conversion; wherein the high-frequency alternating current power supply is used to output alternating current, the oscilloscope is used to observe voltage, the voltage controller is used to control and stabilize voltage, and the high-voltage electrode is used to carry the voltage generated by the high-frequency alternating current power supply and generate plasma. The high-frequency alternating current power supply, the voltage controller, the oscilloscope and the high-voltage electrode are all conventional devices in the art, and their connection mode is also a conventional means in the art, so they will not be described in detail here.

[0077] The carbon capture-conversion integrated unit 3 comprises a plasma reactor, a program flow regulating valve and a temperature control module for low-temperature capture and in-situ conversion of carbon dioxide in air or industrial flue gas; the plasma reactor is internally filled with a bifunctional material; the bifunctional material is coupled with the action of plasma to catalyze the conversion of carbon dioxide into target products. The high-voltage electrode of the plasma generating unit 2 is placed inside the plasma reactor of the carbon capture-conversion integrated unit 3 for generating plasma in the plasma reactor.

[0078] The product separation-purification unit 4 comprises a condensing device and a separation device for separating and purifying the product flowing out of the carbon capture-conversion integrated unit 3, separating the target product and the unreacted raw gas therefrom; wherein the unreacted raw gas reenters the carbon capture-conversion integrated unit 3 to continue to participate in the reaction, thereby improving the utilization rate of the raw gas. The product separation-purification unit 4 is connected with the carbon capture-conversion integrated unit 3.

[0079] Using the above system, the process flow of carbon dioxide capture and in-situ conversion in air or industrial flue gas mainly includes 5 steps:

[0080] S1: Plasma-induced activation of bifunctional material: a reducing gas is introduced into the plasma reactor filled with bifunctional material in the carbon capture-conversion integrated unit, and under the action of plasma, active hydroxyl groups are induced and activated on the surface of the bifunctional material, which facilitates the efficient adsorption of low-concentration carbon dioxide in air or industrial flue gas, and at the same time, the metal catalytic sites in the bifunctional material are induced to be reduced under low-temperature conditions.

[0081] S2: Air / flue gas pretreatment: the air or industrial flue gas input into the system is first subjected to a dust removal and purification device in the pretreatment unit, and the fine particulate dust in the air or industrial flue gas is removed by one or a combination of electrostatic dust removal and mechanical dust removal; if the temperature of the air or industrial flue gas is different from the adsorption reaction temperature of the plasma reactor, the temperature control module in the pretreatment unit is turned on to make the temperature of the air or industrial flue gas reach the adsorption reaction temperature.

[0082] S3: Low-temperature adsorption capture: The pretreated air or industrial flue gas is introduced into the plasma reactor, and the carbon dioxide is captured at low temperature after adsorption treatment by the bifunctional material. The decarburized air or industrial flue gas after adsorption treatment is directly discharged.

[0083] S4: In-situ conversion of adsorbed carbon dioxide: The raw gas is introduced into the plasma reactor through the control valve, and the in-situ conversion of carbon dioxide is carried out under the catalysis of the bifunctional material and the action of the plasma to generate product gas containing target products.

[0084] S5: Product gas separation and purification: The product gas enters the condensing device and the separation device in the separation-purification unit 4 in turn, the separated target products are collected, and the separated raw gas that is not completely reacted is re-introduced into the raw gas pipeline through the control valve for recycling.

[0085] According to the different forms of the reactor of the carbon capture-conversion integrated unit 3, the plasma fixed bed and the plasma fluidized bed are adopted to realize the continuous process, which is specifically described in Example 3 and Example 4.

[0086] Example 3: Continuous CO2 low-temperature capture and in-situ conversion process based on multi-stage plasma fixed bed

[0087] Each unit component: In this embodiment, a multi-stage plasma fixed bed parallel system is adopted Figure 2 ), the adsorption and conversion processes are matched in time, and a double fixed bed plasma reactor is adopted; if the adsorption and conversion processes are matched in time, a three-reactor or more multi-stage plasma fixed bed parallel process can also be adopted. This embodiment takes the process of the double fixed bed plasma reactor as an example, but its scope is not limited to the double fixed bed reactor parallel. The double fixed bed reactor parallel system includes a pretreatment unit (V1, S1, H1), a plasma generation unit (E1, F1, F2, F3), a carbon capture-conversion integrated unit (V2, V3, V4, V5, V6, V7, V8, R1, R2), and a separation-purification unit (D1, P1). The components in the system include: dust removal and purification device S1, program flow regulating valve V1, V10, V11, flow three-way valve V2, V3, V4, V5, V6, V7, V8, V9, plasma fixed bed reactor R1, R2, high-voltage power supply E1, voltage controller F2, oscilloscope F3, high-voltage electrode F1, condensing device D1, separation device P1.

[0088] Process flow: Both plasma fixed bed reactors R1 and R2 are filled with adsorption / catalysis bifunctional materials, which participate in adsorption and conversion in the system; R1 and R2 are connected in parallel, and the state is switched between air or industrial flue gas carbon capture and in-situ conversion. First, open the program flow regulating valve V10, adjust the three-way valves V2, V3, V4, V5 to introduce reducing gas, and the reducing gas is introduced into R1 and R2 after preheating in the preheater H1 to reach the adsorption reaction temperature; start the plasma generating unit to induce and activate the bifunctional material in R1 and R2 in the reducing gas atmosphere. After the induction and activation is completed, the air or low-temperature flue gas after industrial desulfurization and denitrification is delivered into the system through the program flow regulating valve V1, pretreated by the dust removal and purification device S1, and the temperature of the air or industrial flue gas is adjusted by the temperature control module built in the unit; by controlling the program flow regulating valves V2, V3, V4, V5, the switching between the pretreated air or industrial flue gas input into R1 and input into R2 is realized to capture carbon dioxide in the low-temperature flue gas. The raw gas is delivered into the system through the program flow regulating valve V10, and reaches the conversion reaction temperature after passing through the preheater H1; by controlling the program flow regulating valves V2, V3, V4, V5, the switching between the raw gas input into R1 and input into R2 is realized; at the same time, the plasma generating unit is started to generate plasma in the reactor to catalyze the conversion of the adsorbed carbon dioxide in-situ. By controlling the program flow regulating valves V6, V7, V8, V9, the switching between the decarburized flue gas after adsorption treatment flowing out of the reactor R1 and being exhausted and the flue gas flowing out of the reactor R2 and being exhausted is realized. By controlling the program flow regulating valves V6, V7, V8, V9, the switching between the product gas produced by conversion flowing out of the reactor R1 and being collected and the product gas flowing out of the reactor R2 and being collected is realized. The product gas enters the condensing device D1 and the separation device P1 in turn for separation and purification, and the unreacted raw gas separated out is recycled into the raw gas pipeline through the program flow control valve V11.

[0089] Taking methanol as an example, the specific low-temperature plasma promoted carbon capture and in-situ conversion process is as follows:

[0090] Both reactors R1 and R2 are filled with NiCo / K / LDHs bifunctional material with hydrotalcite (LDH) as the substrate loaded with bimetallic NiCo and catalytic K. After plasma-induced activation of the material, the CO2 adsorption capacity of the bifunctional material reaches 3-5 mmol / kg; the raw flue gas is the flue gas after desulfurization and denitrification of a coal-fired power plant, with a temperature of 70-90℃ and a carbon dioxide content of 7-15vol%; the flue gas volume space velocity introduced into the system is controlled to be kept at 2000h -1 -1, and the hydrogen volume space velocity is 1000h -1; the adsorption and conversion reaction temperature is 70-90°C, preferably 80°C; the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption and conversion reaction temperature. First, open the program flow regulating valve V10, adjust the three-way valves V2, V3, V4 and V5 to input hydrogen, heat the hydrogen to the adsorption and conversion reaction temperature through the preheater H1, and start the plasma generating unit, adjust the frequency to 50 Hz and the discharge power to 10 W, and induce the activation of the bifunctional material in R1 and R2 for 5-7 h; after the induction and activation, turn off the plasma generating unit; deliver the flue gas into the system through the flow regulating valve V1, pre-treat the air or industrial flue gas in the dust removal and purification device S1, control the flue gas temperature to be the same as the adsorption and conversion reaction temperature through the temperature control module built in the dust removal and purification device, adjust the three-way flow regulating valves V2, V3, V4 and V5, so that the flue gas enters the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the bifunctional material; adjust the three-way flow regulating valves V6, V7, V8 and V9, so that the decarburized flue gas after the adsorption treatment in R1 is sequentially discharged through the three-way flow regulating valves V6 and V8. When the CO2 adsorption of the bifunctional material in the reactor R1 reaches saturation, adjust the three-way flow regulating valves V2, V3, V4 and V5, switch to input the flue gas into R2 for CO2 adsorption, and start the plasma generating unit in R1, adjust the frequency to 50 Hz and the discharge power to 100 W; deliver the hydrogen into the system through the flow regulating valve V10, preheat it to the adsorption and conversion reaction temperature through the preheater H1, adjust the three-way flow regulating valves V2, V3, V4 and V5, so that the hydrogen enters the reactor R1, and the adsorbed CO2 is converted into the target product crude methanol in situ; adjust the three-way flow regulating valves V6, V7, V8 and V9, so that the crude methanol product in R1 sequentially passes through R6 and R9, and then sequentially enters the condensing device D1 and the separation device P1 (gas-liquid separation device), the methanol is collected as the product after being liquefied by condensation, and the unreacted hydrogen separated out is recycled through the flow regulating valve V11. Similarly, when the CO2 adsorption of the bifunctional material in R2 reaches saturation, adjust the corresponding three-way flow regulating valves to discharge the decarburized flue gas in R2, start the plasma generating unit in R2, input hydrogen into R2, and collect the methanol produced in R2, and then switch to input the flue gas into R1 for CO2 adsorption. In summary, the switching circulation of adsorption and reduction between the fixed bed reactors in the system can achieve a CO2 capture rate of the flue gas of greater than 95%, a CO2 conversion rate of greater than 90%, and a selectivity of methanol in the product of greater than 90%.

[0091] For example, taking methane as the target product, the specific low-temperature plasma promoted carbon capture and in-situ conversion process is as follows:

[0092] Both reactors R1 and R2 are filled with bifunctional materials of RuPt / P / zeolite (or RuPd / P / zeolite) in which bimetallic RuPt (or RuPd) and promoter P are supported on zeolite as a substrate. After plasma-induced activation of the materials, the CO2 adsorption capacity of the bifunctional materials reaches 2-3 mmol / kg; the raw flue gas is the flue gas from a coal-fired power plant after desulfurization and denitrification, and the carbon dioxide content is 3-10 vol%; the volume space velocity of the flue gas introduced into the system is controlled to be 10000 h -1 , and the hydrogen volume space velocity is 10000 h -1; the adsorption and conversion reaction temperature is 15-35°C, preferably 25°C; the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption and conversion reaction temperature. First, open the program flow regulating valve V10, adjust the three-way valves V2, V3, V4 and V5 to input hydrogen, heat the hydrogen to the adsorption and conversion reaction temperature through the preheater H1, and start the plasma generating unit, adjust the frequency to 1 MHz and the discharge power to 5 kW, and induce the activation of the bifunctional material in R1 and R2 for 4-6 min; after the induction and activation, turn off the plasma generating unit; deliver the flue gas at room temperature into the system through the flow regulating valve V1, and pre-treat the air or industrial flue gas in the dust removal and purification device S1, control the flue gas temperature to be the same as the adsorption and conversion reaction temperature through the temperature control module built in the dust removal and purification device; adjust the three-way flow regulating valves V2, V3, V4 and V5 to make the flue gas enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the bifunctional material; adjust the three-way flow regulating valves V6, V7, V8 and V9 to make the decarburized flue gas after the adsorption treatment in R1 pass through the three-way flow regulating valves V6 and V8 in turn and be directly exhausted. When the CO2 adsorption of the bifunctional material in the reactor R1 reaches saturation, adjust the three-way flow regulating valves V2, V3, V4 and V5 to switch to input the flue gas into R2 for CO2 adsorption, and start the plasma generating unit in R1, adjust the frequency to 1 MHz and the discharge power to 5 kW; deliver the hydrogen into the system through the flow regulating valve V10, and adjust the three-way flow regulating valves V2, V3, V4 and V5 to make the hydrogen enter the reactor R1, and convert the adsorbed CO2 into the target product crude methane in situ; adjust the three-way flow regulating valves V6, V7, V8 and V9 to make the crude methane product in R1 pass through R6 and R9 in turn, and then enter the condensing device D1 and the separation device P1 (pressure swing adsorption device) in turn, collect the methane as the product, and separate the unreacted hydrogen which is recycled through the flow regulating valve V11. Similarly, when the CO2 adsorption of the bifunctional material in R2 reaches saturation, adjust the corresponding three-way flow regulating valves to exhaust the decarburized flue gas in R2, start the plasma generating unit in R2, input the hydrogen into R2, and collect the methane produced in R2, and then switch to input the flue gas into R1 for CO2 adsorption. In summary, the switching circulation of adsorption and reduction between the fixed bed reactors in the system can realize that the CO2 capture rate of the flue gas is greater than 93%, the conversion rate of the adsorbed CO2 is greater than 95%, and the selectivity of the methane in the product is greater than 99%.

[0093] For example, taking the target product as synthesis gas, the specific low-temperature plasma promoted carbon capture and in-situ conversion process is as follows:

[0094] Both reactors R1 and R2 are filled with Cu / Ce / CaO bifunctional material in which single metal Cu and promoter Ce are supported on porous calcium oxide (CaO) as substrate. After plasma-induced activation of the material, the CO2 adsorption capacity of the bifunctional material reaches 5-7 mmol / kg; the raw flue gas is the flue gas from a coal-fired power plant after desulfurization and denitrification, with a temperature of 140-160°C and a carbon dioxide content of 18-20 vol%; the volume space velocity of the flue gas into the system is controlled to be 100 h -1 , the volume space velocity of hydrogen is 100 h -1 , and the volume space velocity of methane is 100 h -1; the adsorption and conversion temperature is 190-210°C, preferably 200°C; the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption and conversion temperature. First, open the program flow regulating valve V10, adjust the three-way valves V2, V3, V4 and V5 to input hydrogen, heat the hydrogen to the adsorption and conversion temperature through the preheater H1, and start the plasma generating unit, adjust the frequency to 5000 Hz and the discharge power to 2.5 kW, and induce the activation of the bifunctional material in R1 and R2 for 2-4 hours; after the induction and activation, turn off the plasma generating unit, and send the flue gas into the system through the flow regulating valve V1, and pre-treat the air or industrial flue gas in the dust removal and purification device S1, and control the flue gas temperature in the built-in temperature control module of the dust removal and purification device to be the same as the adsorption and conversion temperature; adjust the three-way flow regulating valves V2, V3, V4 and V5 to make the flue gas enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the bifunctional material; adjust the three-way flow regulating valves V6, V7, V8 and V9 to make the decarburized flue gas after the adsorption treatment in R1 pass through the three-way flow regulating valves V6 and V8 in sequence and be directly exhausted. When the bifunctional material in the reactor R1 is saturated with adsorption, switch to input the flue gas into R2 for CO2 adsorption by adjusting the three-way flow regulating valves V2, V3, V4 and V5, and start the plasma generating unit, adjust the frequency to 5000 Hz and the discharge power to 2500 W; send the methane into the system through the flow regulating valve V10, preheat it to the adsorption and conversion temperature through the preheater H1, and adjust the three-way flow regulating valves V2, V3, V4 and V5 to make the methane enter the reactor R1, and convert the adsorbed CO2 into the target product crude synthesis gas in situ; adjust the three-way flow regulating valves V6, V7, V8 and V9 to make the crude methane product in R1 pass through R6 and R9 in sequence, and then enter the condensing device D1 and the separation device P1 (pressure swing adsorption device) in sequence, produce synthesis gas with a hydrogen-carbon molar ratio of 3, and collect the synthesis gas as the product, and the unreacted methane separated out is recycled through the flow regulating valve V11. Similarly, when the CO2 adsorbed by the bifunctional material in R2 reaches saturation, adjust the corresponding three-way flow regulating valves to exhaust the decarburized flue gas in R2, start the plasma generating unit in R2, input the methane into R2, and collect the synthesis gas produced in R2, and then switch to input the flue gas into R1 for CO2 adsorption. In summary, the switching circulation of adsorption and reduction between the fixed bed reactors in the system can achieve a CO2 capture rate of the flue gas of greater than 99%, a CO2 conversion rate of greater than 97%, and a selectivity of the synthesis gas in the product of greater than 95%.

[0095] For example, the target product is an olefin, and the specific low-temperature plasma promoted carbon capture and in-situ conversion process is as follows:

[0096] Both reactors R1 and R2 are filled with FeCo / K2CO3 / molecular sieve (or FeCo / Na2CO3 / molecular sieve) bifunctional material which is loaded with adsorption sites potassium carbonate (or sodium carbonate) and bimetallic FeCo. After plasma-induced activation of the material, the CO2adsorption capacity of the bifunctional material reaches 2-3 mmol / kg; the raw flue gas is the flue gas from a coal-fired power plant after desulfurization and denitrification, with a temperature of 110-130°C and a carbon dioxide content of 5-7 vol%; the temperature of reactors R1 and R2 is controlled at 100°C; the flue gas volume space velocity entering the system is controlled to remain at 5000 h -1 , and the hydrogen volume space velocity is at 5000 h -1; the adsorption and conversion temperature is 90-110°C, preferably 100°C; the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption and conversion temperature. First, open the program flow regulating valve V10, adjust the three-way valves V2, V3, V4, V5 to input hydrogen, the hydrogen is heated to the adsorption and conversion temperature by the preheater H1, at the same time, start the plasma generating unit, adjust the frequency to 2500 Hz and the discharge power to 1 kW, induce and activate the bifunctional material in R1 and R2 for 0.5-1.5 h; after the induction and activation, turn off the plasma generating unit, adjust the frequency to 200 W, the current to 10 A and the voltage to 20 V; the flue gas is delivered into the system by the flow regulating valve V1, enters the dust removal and purification device S1 for pretreatment, and the temperature of the air or industrial flue gas is adjusted to the adsorption and conversion temperature by the built-in temperature control module in the unit; adjust the three-way flow regulating valves V2, V3, V4, V5 so that the flue gas enters the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the bifunctional material; adjust the three-way flow regulating valves V6, V7, V8, V9 so that the decarburized flue gas after adsorption treatment in R1 passes through the three-way flow regulating valves V6 and V8 in turn and is directly exhausted. When the bifunctional material in the reactor R1 is saturated with adsorption, adjust the three-way flow regulating valves V2, V3, V4, V5 to switch to input the flue gas into R2 for CO2 adsorption, at the same time, start the plasma generating unit in R1, adjust the frequency to 1000 Hz and the discharge power to 200 W; the hydrogen is delivered into the system by the flow regulating valve V10, preheated to the adsorption and conversion temperature by the preheater H1, and adjusted by the three-way flow regulating valves V2, V3, V4, V5 so that the hydrogen enters the reactor R1 to convert the adsorbed CO2 into the target product crude olefin in situ; adjust the three-way flow regulating valves V6, V7, V8, V9 so that the crude olefin product in R1 passes through R6 and R9 in turn, and then enters the condensing device D1 and the separation device P1 (pressure swing adsorption device) in turn, the olefin is collected as the product, and the unreacted hydrogen separated out is recycled through the flow regulating valve V11. Similarly, when the bifunctional material in R2 is saturated with CO2 adsorption, adjust the corresponding three-way flow regulating valves to exhaust the decarburized flue gas in R2, start the plasma generating unit in R2, input hydrogen into R2, and collect the olefin produced in R2, at the same time, switch to input the flue gas into R1 for CO2 adsorption. In summary, the system can achieve a flue gas CO2 capture rate of greater than 96%, a CO2 conversion rate of greater than 94%, and an olefin selectivity in the product of greater than 90%.

[0097] The partial parameters of the above example 3 are summarized in Table 1 below for easy reading and analysis.

[0098] Table 1: Partial parameters of the multi-stage plasma fixed-bed continuous CO2 low-temperature capture and in-situ conversion process

[0099]

[0100] Example 4: Continuous CO2 cryogenic capture and in-situ conversion process based on circulating plasma fluidized bed process

[0101] Each unit component: This embodiment adopts a circulating plasma fluidized bed system Figure 3 ), which includes a circulating plasma fluidized bed system including a pretreatment unit (V1, S1, H1), a plasma generation unit (E1), a carbon capture-conversion integrated unit (V2, C1, C2, R1, R2), and a separation-purification unit (D1, P1). The components in the system include: dust removal and purification device S1, plasma fluidized bed conversion reactor R1, fluidized bed adsorption reactor R1, program flow regulating valve V1, V2, V3, V4, cyclone separator C1, C2, high-voltage power supply E1, voltage controller F2, oscilloscope F3, high-voltage electrode F1, preheater H1, condensing device D1, separation device P1.

[0102] Process flow: The double fluidized beds in the system are conversion reactor R1 and adsorption reactor R2, respectively, and the system realizes continuous carbon dioxide capture and in-situ conversion of air or industrial flue gas through the circulation of adsorption / catalytic dual-functional material particles. First, open the program flow regulating valves V2 and V4, and close the flow regulating valves V1 and V3 to introduce reducing gas, and heat the hydrogen gas to the adsorption reaction temperature through the preheater H1, while starting the plasma generation unit to induce and activate the dual-functional material; after the induction and activation is completed, close the flow regulating valve V4, and transport the air or industrial flue gas into the system through the program flow regulating valve V1, the air or industrial flue gas is pretreated in the dust removal and purification device S1, and the temperature of the air or industrial flue gas is adjusted through the built-in temperature control module in the unit; the pretreated air or industrial flue gas is input into the plasma fluidized bed adsorption reactor R2 for carbon dioxide capture. The raw gas is transported into the system through the program flow regulating valve V2, reaches the conversion reaction temperature after passing through the preheater H1, and enters the plasma fluidized conversion reactor R1; at the same time, the plasma generation unit is started to generate plasma in the reactor to catalyze the in-situ conversion of the adsorbed carbon dioxide. The dual-functional material particles are separated from the product gas and the decarburized flue gas by using the gas-solid cyclone separators C1 and C2, respectively, so that the dual-functional material particles circulate between the adsorption reactor R2 and the conversion reactor R1; the decarburized flue gas separated from the adsorption reactor R2 is directly exhausted; the product gas separated from the conversion reactor R1 is sequentially input into the condensing device D1 and the separation device P1 for separation and purification, and the unreacted raw gas methane or hydrogen separated is re-input into the raw gas pipeline for recycling.

[0103] Taking the target product as syngas as an example, the specific low-temperature plasma promoted carbon capture and in-situ conversion process is as follows:

[0104] The reactors R1 and R2 are both filled with the FeNi / N / activated carbon (or FeNi / N / MgO) bifunctional material which is supported by activated carbon (or MgO) and loaded with bimetallic FeNi and promoter N. After the plasma-induced activation of the material, the CO2 adsorption capacity of the bifunctional material reaches 2-4 mmol / kg; the raw flue gas is the flue gas after desulfurization and denitrification of a coal-fired power plant, the temperature is 120°C, and the carbon dioxide content is 7-15 vol%; the flue gas volume space velocity entering the system is controlled to be 5000 h-1; the hydrogen volume space velocity is 2000 h-1; the adsorption temperature is 140-160°C, preferably 150°C; the conversion temperature is 180-200°C, preferably 190°C; the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, the flow regulating valves V2 and V4 are opened, and the flow regulating valves V1 and V3 are closed to introduce hydrogen, and the plasma generating unit is started, the frequency is adjusted to 100 Hz, and the discharge power is adjusted to 50 W, and the bifunctional material in R1 and R2 is induced and activated for 5-7 h; after the induction and activation is completed, the plasma generating unit is turned off, the flow regulating valve V4 is closed, and the flue gas is sent into the system through the flow regulating valve V1, the air or industrial flue gas enters the dust removal and purification device S1 for pretreatment, and the temperature of the flue gas is controlled by the built-in temperature control module to be the adsorption reaction temperature; the pretreated air or industrial flue gas is input into the plasma fluidized bed adsorption reactor R2 for carbon dioxide capture. The temperature of the reactor R1 is controlled to reach the conversion reaction temperature, hydrogen is sent into the system through the program flow regulating valve V2, reaches the conversion reaction temperature after passing through the preheater H1, and enters the plasma fluidized conversion reactor R1; at the same time, the plasma generating unit is started to generate plasma in the reactor, the frequency is adjusted to 3000 Hz, and the discharge power is adjusted to 1000 W, and the conversion of the adsorbed carbon dioxide is carried out in situ. The gas-solid cyclone separators C1 and C2 are used to separate the bifunctional material particles from the product gas and the decarburized flue gas respectively, so that the bifunctional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The decarburized flue gas separated from the adsorption reactor R2 is directly exhausted. The crude synthesis gas separated from the conversion reactor R1 enters the condensing device D1 to remove condensed water, and then enters the separation device P1 (pressure swing adsorption device) to separate and purify excess hydrogen by low-temperature pressure swing adsorption, so as to ensure that the hydrogen-carbon molar ratio in the product synthesis gas is close to 2; the unreacted raw material gas hydrogen separated by the program flow control valve V3 enters the raw material gas pipeline for recycling. In summary, the system can realize that the carbon dioxide capture rate in the flue gas is greater than 95%, the conversion rate of the adsorbed CO2 is greater than 90%, and the selectivity of the product synthesis gas is close to 99%. -1 -1

[0105] For example, taking methane as the target product, the specific low-temperature plasma-promoted carbon capture and in-situ conversion process is as follows:

[0106] ​​The reactors R1 and R2 are both filled with the RhNi / Na / modified ion resin bifunctional material grafted with RhNi and the adjuvant Na on the modified ion resin as the adsorption carrier. After plasma-induced activation of the material, the CO2 adsorption capacity of the bifunctional material is 1-2 mmol / kg; the low-concentration carbon dioxide content in air is 0.04 vol%; the air volume space velocity into the system is controlled to be 8000 h-1 at normal temperature; the hydrogen volume space velocity is 8000 h-1; the adsorption temperature is 15-35°C, preferably 25°C; the conversion temperature is 70-90°C, preferably 80°C; the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, the flow regulating valves V2 and V4 are opened, and the flow regulating valves V1 and V3 are closed to introduce hydrogen, and the plasma generating unit is started, the frequency is adjusted to 1000 Hz, and the discharge power is adjusted to 2000 W to induce activation of the bifunctional material in R1 and R2 for 2-4 h; after the induction activation is completed, the plasma generating unit is turned off, the flow regulating valve V4 is closed, and the air at normal temperature is delivered into the system through the program flow regulating valve V1, the air enters the dust removal and purification device S1 for pretreatment, the air temperature is controlled by the built-in temperature control module to be the adsorption reaction temperature, and the pretreated air is input into the plasma fluidized bed adsorption reactor R2 for carbon dioxide capture. The temperature of the reactor R1 is controlled to reach the conversion reaction temperature, hydrogen is delivered into the system through the program flow regulating valve V2, and the hydrogen reaches the conversion reaction temperature after passing through the preheater H1 and enters the plasma fluidized conversion reactor R1; at the same time, the plasma generating unit is started to generate plasma in the reactor, the frequency is adjusted to 1500 Hz, and the discharge power is adjusted to 500 W to perform in-situ catalytic adsorption of carbon dioxide conversion. The gas-solid cyclone separators C1 and C2 are used to separate the bifunctional material particles from the product gas and the decarburized air respectively, so that the bifunctional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The decarburized air separated from the adsorption reactor R2 is directly exhausted. The crude synthesis gas separated from the conversion reactor R1 enters the condensing device D1 to remove condensed water, and then enters the separation device P1 (pressure swing adsorption device) to separate and purify excess hydrogen by low-temperature pressure swing adsorption to ensure that the hydrogen-carbon molar ratio in the product synthesis gas is close to 3; the unreacted raw material gas hydrogen separated through the program flow control valve V3 is introduced into the raw material gas pipeline for recycling. In summary, the system can achieve a carbon dioxide capture rate of greater than 98% in air, a CO2 conversion rate of greater than 96%, and a methane selectivity of close to 98% in the product. -1 -1 The hydrogen volume space velocity is 8000 h -1 ; the adsorption temperature is 15-35°C, preferably 25°C; the conversion temperature is 70-90°C, preferably 80°C; the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, the flow regulating valves V2 and V4 are opened, and the flow regulating valves V1 and V3 are closed to introduce hydrogen, and the plasma generating unit is started, the frequency is adjusted to 1000 Hz, and the discharge power is adjusted to 2000 W to induce activation of the bifunctional material in R1 and R2 for 2-4 h; after the induction activation is completed, the plasma generating unit is turned off, the flow regulating valve V4 is closed, and the air at normal temperature is delivered into the system through the program flow regulating valve V1, the air enters the dust removal and purification device S1 for pretreatment, the air temperature is controlled by the built-in temperature control module to be the adsorption reaction temperature, and the pretreated air is input into the plasma fluidized bed adsorption reactor R2 for carbon dioxide capture. The temperature of the reactor R1 is controlled to reach the conversion reaction temperature, hydrogen is delivered into the system through the program flow regulating valve V2, and the hydrogen reaches the conversion reaction temperature after passing through the preheater H1 and enters the plasma fluidized conversion reactor R1; at the same time, the plasma generating unit is started to generate plasma in the reactor, the frequency is adjusted to 1500 Hz, and the discharge power is adjusted to 500 W to perform in-situ catalytic adsorption of carbon dioxide conversion. The gas-solid cyclone separators C1 and C2 are used to separate the bifunctional material particles from the product gas and the decarburized air respectively, so that the bifunctional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The decarburized air separated from the adsorption reactor R2 is directly exhausted. The crude synthesis gas separated from the conversion reactor R1 enters the condensing device D1 to remove condensed water, and then enters the separation device P1 (pressure swing adsorption device) to separate and purify excess hydrogen by low-temperature pressure swing adsorption to ensure that the hydrogen-carbon molar ratio in the product synthesis gas is close to 3; the unreacted raw material gas hydrogen separated through the program flow control valve V3 is introduced into the raw material gas pipeline for recycling. In summary, the system can achieve a carbon dioxide capture rate of greater than 98% in air, a CO2 conversion rate of greater than 96%, and a methane selectivity of close to 98% in the product.

[0107] For example, the target product is methanol, and the specific low-temperature plasma-promoted carbon capture and in-situ conversion process is as follows:

[0108] Both reactors R1 and R2 are filled with CuZn / Ce / NH2-molecular sieve bifunctional material impregnated with CuZn and Ce promoters on the molecular sieve grafted with amino groups. After plasma-induced activation of the material, the CO2 adsorption capacity of the bifunctional material reaches 4-5 mmol / kg. The raw flue gas is flue gas from a coal-fired power plant after desulfurization and denitrification, with a temperature of 70-90°C and a CO2 content of 12-15 vol%. The flue gas volume space velocity entering the system is controlled to be 4000 h-1, and the hydrogen volume space velocity is 5000 h-1. The adsorption temperature is 70-90°C, preferably 80°C. The conversion temperature is 70-90°C, preferably 80°C. The temperature of reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, open flow regulating valves V2 and V4, and close flow regulating valves V1 and V3 to introduce hydrogen. Start the plasma generating unit, adjust the frequency to 800 Hz and the discharge power to 500 W, and induce activation of the bifunctional material in R1 and R2 for 4-6 h. After the induction activation is completed, close the plasma generating unit and close flow regulating valve V4. The flue gas is delivered into the system through flow regulating valve V1, enters the dust removal and purification device S1 for pretreatment, and the flue gas temperature is controlled by the built-in temperature control module to be the adsorption reaction temperature. The pretreated flue gas is input into the plasma fluidized bed adsorption reactor R2 for CO2 capture. The temperature of reactor R1 is controlled to reach the conversion reaction temperature, and hydrogen is delivered into the system through program flow regulating valve V2, reaches the conversion reaction temperature after passing through preheater H1, and enters the plasma fluidized conversion reactor R1. At the same time, start the plasma generating unit to generate plasma in the reactor, adjust the frequency to 2000 Hz and the discharge power to 1200 W, and perform in-situ catalytic adsorption CO2 conversion. Gas-solid cyclone separators C1 and C2 are used to separate the bifunctional material particles from the product gas and the decarburized flue gas, respectively, so that the bifunctional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The decarburized flue gas separated from the adsorption reactor R2 is directly exhausted. The crude methanol separated from the conversion reactor R1 is input into condensing device D1 to remove condensed water, and then into separation device P1 (gas-liquid separation device) to separate excess hydrogen by gas-liquid separation. The unreacted raw material gas hydrogen separated through program flow control valve V3 is recycled into the raw material gas pipeline. In summary, the system can achieve a CO2 capture rate of flue gas of greater than 95%, a CO2 conversion rate of greater than 95%, and a methanol selectivity of close to 95% in the product. -1 , the hydrogen volume space velocity is 5000 h -1 -1. The adsorption temperature is 70-90°C, preferably 80°C. The conversion temperature is 70-90°C, preferably 80°C. The temperature of reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, open flow regulating valves V2 and V4, and close flow regulating valves V1 and V3 to introduce hydrogen. Start the plasma generating unit, adjust the frequency to 800 Hz and the discharge power to 500 W, and induce activation of the bifunctional material in R1 and R2 for 4-6 h. After the induction activation is completed, close the plasma generating unit and close flow regulating valve V4. The flue gas is delivered into the system through flow regulating valve V1, enters the dust removal and purification device S1 for pretreatment, and the flue gas temperature is controlled by the built-in temperature control module to be the adsorption reaction temperature. The pretreated flue gas is input into the plasma fluidized bed adsorption reactor R2 for CO2 capture. The temperature of reactor R1 is controlled to reach the conversion reaction temperature, and hydrogen is delivered into the system through program flow regulating valve V2, reaches the conversion reaction temperature after passing through preheater H1, and enters the plasma fluidized conversion reactor R1. At the same time, start the plasma generating unit to generate plasma in the reactor, adjust the frequency to 2000 Hz and the discharge power to 1200 W, and perform in-situ catalytic adsorption CO2 conversion. Gas-solid cyclone separators C1 and C2 are used to separate the bifunctional material particles from the product gas and the decarburized flue gas, respectively, so that the bifunctional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The decarburized flue gas separated from the adsorption reactor R2 is directly exhausted. The crude methanol separated from the conversion reactor R1 is input into condensing device D1 to remove condensed water, and then into separation device P1 (gas-liquid separation device) to separate excess hydrogen by gas-liquid separation. The unreacted raw material gas hydrogen separated through program flow control valve V3 is recycled into the raw material gas pipeline. In summary, the system can achieve a CO2 capture rate of flue gas of greater than 95%, a CO2 conversion rate of greater than 95%, and a methanol selectivity of close to 95% in the product.

[0109] For example, taking olefins as the target product, the specific low-temperature plasma-promoted carbon capture and in-situ conversion process is as follows:

[0110] The reactors R1 and R2 are both filled with Co / Na-K / activated carbon bifunctional material, in which Co is impregnated with activated carbon as adsorption carrier and KOH and NaOH as adsorption carrier. After plasma-induced activation of the material, the CO2 adsorption capacity of the bifunctional material reaches 1-2 mmol / kg. The raw flue gas is flue gas from a coal-fired power plant after desulfurization and denitrification, with a temperature of 40-60°C and a CO2 content of 3-5 vol%. The flue gas volume space velocity entering the system is controlled to be 7000 h-1, and the hydrogen volume space velocity is 8000 h-1; the adsorption temperature is 80-100°C, preferably 90°C; the conversion temperature is 140-160°C, preferably 150°C; and the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, the flow regulating valve V2 is adjusted to introduce hydrogen, and the plasma generating unit is started, with a frequency of 3200 Hz and a discharge power of 1000 W, to induce and activate the bifunctional material in R1 and R2 for 3-4 h; after the induction and activation is completed, the plasma generating unit is turned off, the flow regulating valve V4 is closed, and the flue gas is delivered into the system through the program flow regulating valve V1, enters the dust removal and purification device S1 for pretreatment, and the flue gas temperature is controlled by the built-in temperature control module to be the conversion reaction temperature; the pretreated flue gas is input into the plasma fluidized bed adsorption reactor R2 for CO2 capture. The temperature of the reactor R1 is controlled to reach the conversion reaction temperature, hydrogen is delivered into the system through the program flow regulating valve V2, reaches the adsorption reaction and conversion reaction temperature after passing through the preheater H1, and enters the plasma fluidized conversion reactor R1; at the same time, the plasma generating unit is started to generate plasma in the reactor, with a frequency of 1500 Hz and a discharge power of 500 W, to perform in-situ catalytic adsorption of CO2 conversion. The gas-solid cyclone separators C1 and C2 are used to separate the bifunctional material particles from the product gas and the decarburized flue gas, respectively, so that the bifunctional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The decarburized flue gas separated from the adsorption reactor R2 is directly exhausted. The crude methanol separated from the conversion reactor R1 is input into the condensing device D1 to remove condensed water, and then into the separation device P1 to separate excess hydrogen by pressure swing adsorption. The unreacted raw material gas hydrogen separated by the program flow control valve V3 is recycled to the raw material gas pipeline. In summary, the system can achieve a CO2 capture rate of the flue gas of greater than 95%, a CO2 conversion rate of greater than 97%, and a selectivity of olefins in the product close to 92%. -1 , the hydrogen volume space velocity is 8000 h -1 ; the adsorption temperature is 80-100°C, preferably 90°C; the conversion temperature is 140-160°C, preferably 150°C; and the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, the flow regulating valve V2 is adjusted to introduce hydrogen, and the plasma generating unit is started, with a frequency of 3200 Hz and a discharge power of 1000 W, to induce and activate the bifunctional material in R1 and R2 for 3-4 h; after the induction and activation is completed, the plasma generating unit is turned off, the flow regulating valve V4 is closed, and the flue gas is delivered into the system through the program flow regulating valve V1, enters the dust removal and purification device S1 for pretreatment, and the flue gas temperature is controlled by the built-in temperature control module to be the conversion reaction temperature; the pretreated flue gas is input into the plasma fluidized bed adsorption reactor R2 for CO2 capture. The temperature of the reactor R1 is controlled to reach the conversion reaction temperature, hydrogen is delivered into the system through the program flow regulating valve V2, reaches the adsorption reaction and conversion reaction temperature after passing through the preheater H1, and enters the plasma fluidized conversion reactor R1; at the same time, the plasma generating unit is started to generate plasma in the reactor, with a frequency of 1500 Hz and a discharge power of 500 W, to perform in-situ catalytic adsorption of CO2 conversion. The gas-solid cyclone separators C1 and C2 are used to separate the bifunctional material particles from the product gas and the decarburized flue gas, respectively, so that the bifunctional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The decarburized flue gas separated from the adsorption reactor R2 is directly exhausted. The crude methanol separated from the conversion reactor R1 is input into the condensing device D1 to remove condensed water, and then into the separation device P1 to separate excess hydrogen by pressure swing adsorption. The unreacted raw material gas hydrogen separated by the program flow control valve V3 is recycled to the raw material gas pipeline. In summary, the system can achieve a CO2 capture rate of the flue gas of greater than 95%, a CO2 conversion rate of greater than 97%, and a selectivity of olefins in the product close to 92%.

[0111] The parameters of the above Example 4 are summarized in Table 2 below for ease of reading and analysis.

[0112] Table 2: Partial parameters of continuous CO2 low-temperature capture and in-situ conversion process based on circulating plasma fluidized bed process

[0113]

[0114]

[0115] Comparative Example 1: Low temperature CO2 capture and in-situ conversion with plasma multi-stage fixed bed coupled with hydrotalcite (LDH) adsorbent

[0116] The hydrotalcite (LDH) adsorbent was prepared by the method in Reference Example 1, and CO2 capture and conversion was carried out using the multi-stage plasma fixed bed system of Example 3. In the plasma reactor of this comparative example, only hydrotalcite adsorbent was filled, not the bifunctional material, and the adsorbent was not plasma-induced activated; the specific low temperature plasma promoted carbon capture and in-situ conversion process is as follows:

[0117] The reactors R1 and R2 were both filled with hydrotalcite (LDH) adsorbent. The adsorbent was not plasma-induced activated, and the CO2 adsorption capacity was 1 mol / kg; the raw flue gas was the flue gas after desulfurization and denitrification of a coal-fired power plant, with a temperature of 70-90°C and a carbon dioxide content of 7-15 vol%; the flue gas volume space velocity entering the system was controlled to be 2000 h -1 , and the hydrogen volume space velocity was 1000 h -1; the adsorption and conversion temperature is 70-90°C, preferably 80°C. The flue gas is delivered into the system through flow regulating valve V1, and the air or industrial flue gas is pre-treated in dust removal and purification device S1, and the temperature of the flue gas is controlled by the temperature control module in the dust removal and purification device to be the same as the adsorption and conversion temperature; the three-way flow regulating valves V2, V3, V4 and V5 are adjusted so that the flue gas enters the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the hydrotalcite; the three-way flow regulating valves V6, V7, V8 and V9 are adjusted so that the decarburized flue gas after adsorption treatment in R1 is directly discharged through the three-way flow regulating valves V6 and V8. When the CO2 adsorption of the hydrotalcite in the reactor R1 reaches saturation, the three-way flow regulating valves V2, V3, V4 and V5 are adjusted to switch to the input of the flue gas to R2 for CO2 adsorption, and the plasma generating unit in R1 is started at the same time, with a frequency of 50 Hz and a discharge power of 100 W; the hydrogen is delivered into the system through the flow regulating valve V10, preheated to the adsorption and conversion temperature through the preheater H1, and the three-way flow regulating valves V2, V3, V4 and V5 are adjusted so that the hydrogen enters the reactor R1 to convert the adsorbed CO2, and it is detected that the main conversion products are CO, CO2 and a small amount of methane; the crude CO product enters the condensing device D1 and the separation device P1 (pressure swing adsorption device), and the unreacted hydrogen passes through the flow regulating valve V11 for reuse. Similarly, when the CO2 adsorption of the hydrotalcite adsorbent in R2 reaches saturation, the corresponding three-way flow regulating valves are adjusted to discharge the decarburized flue gas in R2, and the plasma generating unit in R2 is started to input hydrogen into R2, and the CO generated in R2 is collected, and then the input of the flue gas to R1 for CO2 adsorption is switched. In summary, the system can achieve a flue gas CO2 capture rate of only about 70%, an adsorbed CO2 conversion rate of about 40%, and a CO selectivity of about 60%, and the target product of methanol cannot be obtained.

[0118] Comparative Example 2: Low-temperature CO2 capture and in-situ conversion based on plasma multi-stage fixed-bed NiCo bimetallic catalyst

[0119] The NiCo bimetallic catalyst was prepared by the method in Reference Example 1, and the multi-stage plasma fixed-bed system of Example 3 was used for CO2 capture and conversion. In the plasma reactor of this comparative example, only the NiCo bimetallic catalyst was filled, not the bifunctional material, and the catalyst was not activated by plasma; the specific low-temperature plasma promoted carbon capture and in-situ conversion process is as follows:

[0120] Reactors R1 and R2 were both filled with NiCo bimetallic catalysts. Due to the extremely limited number of basic adsorption sites on the surface of the NiCo bimetallic catalyst, its CO2 adsorption capacity was only 0.1 mol / kg without plasma-induced activation. Even after plasma-induced activation, the CO2 adsorption capacity only slightly increased to approximately 0.15 mol / kg. This demonstrates that metal catalysts without synergistic adsorption components do not possess excellent CO2 adsorption performance. The feed gas was desulfurized and denitrified flue gas from a coal-fired power plant, with a temperature of 70–90℃ and a carbon dioxide content of 7–15 vol%. The volume hourly space velocity (VHSV) of the flue gas introduced into the system was maintained at 2000 h⁻¹. -1 The volume hourly space velocity of hydrogen is 1000 h⁻¹. -1 The adsorption and conversion temperature is 70–90℃, preferably 80℃. Flue gas is fed into the system through flow regulating valve V1. Air or industrial flue gas enters the dust removal and purification device S1 for pretreatment. The temperature of the flue gas is controlled to be the same as the adsorption and conversion temperature by the built-in temperature control module of the dust removal and purification device. The three-way flow regulating valves V2, V3, V4, and V5 are adjusted to allow the flue gas to enter reactor R1, where carbon dioxide in the flue gas is adsorbed by the NiCo bimetallic catalyst. The three-way flow regulating valves V6, V7, V8, and V9 are adjusted so that the decarbonized flue gas in R1, after adsorption treatment, is directly discharged into the air through the three-way flow regulating valves V6 and V8 in sequence. The NiCo bimetallic catalyst in reactor R1 quickly reaches CO2 adsorption saturation. When saturation is reached, the three-way flow control valves V2, V3, V4, and V5 are adjusted to switch the flue gas input to R2 for CO2 adsorption. At the same time, the plasma generation unit in R1 is started, with the frequency adjusted to 50Hz and the discharge power to 100W. Hydrogen is introduced into the system through the flow control valve V10 and preheated to the adsorption and conversion temperature by the preheater H1. The three-way flow control valves V2, V3, V4, and V5 are adjusted to allow hydrogen to enter reactor R1, converting the adsorbed CO2 in situ. The main conversion products were detected as CH3OH, CH4, CO, and CO2. The crude methanol product sequentially enters the condenser D1 and the separation device P1 (gas-liquid separation device). The unreacted hydrogen is recycled through the flow control valve V11. Similarly, when the NiCo bimetallic catalyst in R2 reaches CO2 saturation, the corresponding three-way flow control valve is adjusted to discharge the decarbonized flue gas from R2, and the plasma generation unit in R2 is activated to introduce hydrogen into R2 and collect the methanol produced in R2. Simultaneously, the system switches back to feeding flue gas into R1 for CO2 adsorption. In summary, using this system, the CO2 capture rate is only about 20%, the CO2 conversion rate is about 60%, and the methanol selectivity is only about 50%.

[0121] Comparative Example 3: Low-temperature CO2 capture and in-situ conversion based on plasma-coupled multi-level fixed bed with hydrotalcite (LDH) adsorbent and NiCo bimetallic catalyst

[0122] The water sludge stone (LDH) adsorbent and K-containing NiCo bimetallic catalyst were prepared according to the method in Reference Example 1, respectively, and CO2 capture and in-situ conversion were carried out using the multi-stage plasma fixed bed system of Example 3. The plasma reactor of the present comparative example was only filled with mixed particles of water sludge stone adsorbent and K-containing NiCo bimetallic catalyst, instead of bifunctional material, and the catalyst was not subjected to plasma-induced activation; the specific low-temperature plasma promoted carbon capture and in-situ conversion process is as follows:

[0123] The reactor R1 and R2 were both filled with K / NiCo-LDHs particles (NiCo bimetallic: LDH: K = 48.85%: 48.85%: 2.30%) which were simply physically and uniformly mixed with water sludge stone adsorbent and K-containing NiCo bimetallic catalyst at a mass ratio of 1:1. The CO2 adsorption capacity of the NiCo-LDHs particles without plasma-induced activation was 0.5 mol / kg; the raw flue gas was the flue gas after desulfurization and denitrification of a coal-fired power plant, with a temperature of 70-90°C and a carbon dioxide content of 7-15 vol%; the flue gas volume space velocity entering the system was controlled to be 2000 h-1, and the hydrogen volume space velocity was 1000 h-1. -1 -1 ​; The adsorption and conversion temperature is preferably 80°C. The flue gas is delivered into the system through flow regulating valve V1, and the air or industrial flue gas is pretreated in dust removal and purification device S1, and the temperature of the flue gas is controlled by the temperature control module built in the dust removal and purification device to be the same as the adsorption and conversion temperature. The three-way flow regulating valves V2, V3, V4 and V5 are adjusted so that the flue gas enters the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the NiCo-LDHs particles. The three-way flow regulating valves V6, V7 and V8 are adjusted so that the decarburized flue gas treated by adsorption in R1 passes through the three-way flow regulating valves V6 and V8 in turn and is directly exhausted. When the NiCo-LDHs particles in the reactor R1 reach saturation by adsorption, the three-way flow regulating valves V2, V3, V4 and V5 are adjusted to switch to the input of the flue gas into R2 for CO2 adsorption, and the plasma generating unit in R1 is started at a frequency of 50Hz and a discharge power of 100W. Hydrogen is delivered into the system through flow regulating valve V10, preheated to the adsorption and conversion temperature by preheater H1, and adjusted by three-way flow regulating valves V2, V3, V4 and V5 so that the hydrogen enters the reactor R1 to convert the adsorbed CO2. The main conversion products detected are CH3OH, CH4, CO and CO2. The crude methanol product enters condensing device D1 and separation device P1 (gas-liquid separation device) in turn, and the unreacted hydrogen passes through flow regulating valve V11 for reuse. Similarly, when the CO2 adsorbed by the NiCo-LDHs particles in R2 reaches saturation, the corresponding three-way flow regulating valves are adjusted to exhaust the decarburized flue gas in R2, and the plasma generating unit in R2 is started to introduce hydrogen into R2, and the methanol produced in R2 is collected, and then the flue gas is input into R1 for CO2 adsorption. In summary, the system can achieve a flue gas carbon dioxide capture rate of only 55%, an adsorbed CO2 conversion rate of 70%, and a methanol selectivity of only 55%.

Claims

1. A method for carbon dioxide capture and in-situ conversion, characterized in that, The method includes a system for coordinating carbon dioxide capture and in-situ conversion using low-temperature plasma coupled bifunctional materials. The system includes a pretreatment unit (1), a plasma generation unit (2), an integrated carbon capture-conversion unit (3), and a separation-purification unit (4). The carbon dioxide is carbon dioxide from air or industrial flue gas. The integrated carbon capture-conversion unit (3) is filled with bifunctional materials, which include adsorption components and catalytic components. The reaction temperature of the integrated carbon capture-conversion unit (3) is 0–210°C, and the reaction is an adsorption reaction or a conversion reaction. The catalytic components are highly dispersed on an adsorption component substrate with a porous structure. In the method, the carbon capture-conversion integrated unit (3) captures and converts carbon dioxide in air or industrial flue gas under the action of plasma and reducing gas, specifically including the following steps: S1: Plasma-induced activation of bifunctional materials: A reducing gas is introduced into the plasma reactor filled with bifunctional materials in the carbon capture-conversion integrated unit (3). Under the action of plasma, active hydroxyl groups are generated on the surface of the activated bifunctional materials, which facilitates the efficient adsorption of low-concentration carbon dioxide in air or industrial flue gas. At the same time, the metal catalytic sites in the bifunctional materials are induced to be reduced under low temperature conditions. S2: Air / Flue Gas Pretreatment: The air or industrial flue gas entering the system first passes through the dust removal and purification device in the pretreatment unit (1), and removes fine particulate dust from the air or industrial flue gas through one or a combination of electrostatic dust removal and mechanical dust removal; if the temperature of the air or industrial flue gas is different from the adsorption reaction temperature of the plasma reactor, the temperature control module in the pretreatment unit (1) is turned on to make the temperature of the air or industrial flue gas reach the adsorption reaction temperature; S3: Low-temperature adsorption and capture: Pretreated air or industrial flue gas is introduced into the plasma reactor and adsorbed by bifunctional materials to achieve low-temperature capture of carbon dioxide; the decarbonized air or industrial flue gas after adsorption treatment is directly discharged. S4: In-situ conversion of adsorbed carbon dioxide: By controlling the valve, the raw material gas is introduced into the plasma reactor, and under the catalysis of the bifunctional material and the action of plasma, carbon dioxide is converted in situ to generate product gas containing the target product. S5: Product gas separation and purification: The product gas enters the condenser and separation device in the separation-purification unit (4) in sequence, collects the separated target product, and re-enters the unreacted raw material gas into the raw material gas pipeline for recycling through the control valve.

2. The method as described in claim 1, characterized in that, The adsorbent component is selected from one or more combinations of hydrotalcite, zeolite, activated carbon, modified ion exchange resin, calcium oxide, magnesium oxide, solid supported amino groups, sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide; the catalytic component is selected from one or more combinations of metals or metal oxides of iron, nickel, cobalt, copper, ruthenium, platinum, palladium, rhodium, and zinc; the mass percentage of the adsorbent component in the bifunctional material is 0.1–99 wt%, and the mass percentage of the catalytic component in the bifunctional material is 0.1–60 wt%.

3. The method as described in claim 1, characterized in that, The bifunctional material further includes a co-catalytic component, which is selected from one or more combinations of cerium, potassium, sodium, phosphorus, and nitrogen; the mass percentage of the co-catalytic component in the bifunctional material is 0-20 wt%; the co-catalytic component is highly dispersed on an adsorption component substrate with a porous structure.

4. The method as described in claim 1, characterized in that, The pretreatment unit (1) includes a dust removal and purification device and a temperature control module; the pretreatment unit (1) is connected to the carbon capture-conversion integrated unit (3); The plasma generating unit (2) includes a high-frequency AC power supply, a voltage controller, an oscilloscope and a high-voltage electrode, wherein the high-voltage electrode is embedded inside the plasma reactor of the carbon capture-conversion integrated unit (3); The integrated carbon capture-conversion unit (3) includes a plasma reactor, a programmed flow control valve, and a temperature control module; The plasma reactor is either a multi-stage parallel fixed-bed plasma reactor or a circulating fluidized-bed plasma reactor; the plasma reactor is filled with a bifunctional material. The separation-purification unit (4) includes a condensation device and a separation device, wherein the separation device is a gas-liquid separation device or a pressure swing adsorption device; the separation-purification unit (4) is connected to the carbon capture-conversion integrated unit (3).

5. The method as described in claim 1, characterized in that, The feed gas is selected from one or more combinations of hydrogen, water vapor, ammonia, carbon monoxide, methane, and ethane.

6. The method as described in claim 1, characterized in that, In step S1, the reducing gas is selected from one or more combinations of hydrogen, ammonia, carbon monoxide, methane and ethane, and the reducing gas is heated to the adsorption reaction temperature by a preheater before being introduced into the plasma reactor; the time for inducing activation of the bifunctional material is 1 min to 10 h.

7. The method as described in claim 1, characterized in that, In step S2, the volume hourly space velocity (VHSV) of the air or industrial flue gas introduced into the plasma reactor is 10–10,000 h⁻¹. -1 .

8. The method as described in claim 1, characterized in that, In step S3, the volume hourly space velocity (VHSV) of the feed gas introduced into the plasma reactor is 100–10000 h⁻¹. -1 The target product is selected from carbon monoxide, syngas, methane, methanol, or olefins.

9. The method as described in claim 1, wherein the plasma reactor is a multi-stage parallel plasma fixed-bed reactor, wherein the multi-stage parallel plasma fixed-bed reactor is a dual-parallel plasma fixed-bed reactor; when the carbon dioxide adsorption capacity of the bifunctional material in one of the reactors reaches saturation, the plasma generating unit (2) corresponding to the reactor is started, and raw material gas is introduced into the reactor for in-situ conversion by controlling the valve, while switching to introducing air or industrial flue gas into the other reactor for carbon dioxide adsorption.

10. The method as described in claim 1, wherein the plasma reactor is a circulating plasma fluidized bed reactor, comprising an adsorption reactor and a conversion reactor; when the carbon dioxide adsorption capacity of the bifunctional material in the adsorption reactor reaches saturation, a cyclone separator is used to separate the bifunctional material from the adsorption reactor and the conversion reactor, and then the material is introduced into the two reactors respectively through pipelines to achieve the replacement of the bifunctional material in the two reactors.

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