System and method for low-temperature plasma coupling difunctional material synergistic carbon dioxide capture and in-situ conversion

Abstract

The invention discloses a low-temperature plasma coupled dual-function material synergistic carbon dioxide capture and in-situ conversion system, which achieves the synergistic effect of low-temperature plasma and an adsorption and catalysis dual-function material by coupling the low-temperature plasma and the adsorption and catalysis dual-function material. Therefore, CO2 is directly captured and activated in a mild state and is catalytically converted into high-added-value chemicals in situ, strict conditions of heating desorption and high-temperature CO2 conversion are avoided, and the bottleneck that direct CO2 capturing and high-efficiency in-situ conversion of low-temperature flue gas are difficult to realize in a mild condition in the prior art is solved. The invention also discloses a method for carrying out carbon dioxide capture and in-situ conversion by using the system.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon capture and utilization, and specifically, relates to a system and method for low-temperature plasma coupled dual-functional materials to coordinate carbon dioxide capture and in-situ conversion. Background Art

[0002] Under the goal of carbon neutrality, CO2 capture, utilization and storage (CCUS) is an important technology to ensure the sustainable, large-scale, low-carbon utilization of traditional fossil energy. However, traditional CCUS technology has problems such as high energy consumption, high cost and low timeliness, which greatly hinders its promotion and application. In recent years, new technologies for CO2 capture and in-situ conversion have received close attention. According to the temperature range of flue gas from emission sources and carbon-based target products, this technology designs dual-functional materials for capture and catalytic conversion, realizes CO2 capture and in-situ conversion in the same reactor, and the converted dual-functional materials are regenerated and enter the cycle of carbon capture and in-situ conversion again, avoiding the desorption, compression and transportation process of captured CO2 in conventional CCUS technology, thereby reducing the system energy consumption of waste carbon resource conversion and utilization. However, due to the thermodynamic stability of CO2 molecules, the CO2 conversion process often requires the injection of a large amount of energy for activation and conversion under harsh conditions such as high temperature and high pressure. Therefore, at this stage, domestic and foreign research mainly focuses on medium and high temperature CO2 capture and in-situ conversion to produce simple C1 chemicals such as methane and syngas. It is worth noting that most industrial flue gases are currently equipped with heat exchange systems to make full use of waste heat to save energy and reduce consumption. After denitrification and desulfurization, the flue gas is usually at a low temperature (<150°C) and the CO2 concentration is low. There is a temperature mismatch problem between the CO2 capture of low-temperature flue gas and the high-temperature in-situ conversion process. The specification of Chinese invention patent application CN112569739A discloses a system for high-temperature capture of carbon dioxide and in-situ thermal catalytic conversion to synthesis gas, which is suitable for direct carbon capture and conversion of high-temperature flue gas (600-800°C) into synthesis gas, but is not suitable for carbon capture-conversion of low-temperature flue gas. Therefore, how to achieve low-concentration CO2 capture and in-situ efficient conversion into high-value-added chemicals such as methane, methanol, and olefins under mild conditions such as low temperature and normal pressure has become an important research direction to break through the bottleneck of high energy consumption and high cost of CCUS technology.

[0003] Low-temperature CO2 catalytic conversion technologies mainly include photocatalysis and electrocatalysis. Photocatalytic technology can directly use sunlight as energy, and the reaction conditions are mild, but due to low electron production efficiency and insufficient proton supply, the light energy utilization rate, conversion efficiency and product selectivity of this technology are low. Electrocatalytic technology has high energy utilization, but due to the competition between CO2 reduction reaction and hydrogen evolution reaction, as well as the low solubility of CO2 in water, the conversion efficiency and product selectivity are low. The emerging low-temperature CO2 plasma catalytic conversion technology can promote CO2 activation under mild conditions due to the low temperature of non-thermal plasma but high electron energy (the temperature can reach thousands to tens of thousands of K), and at the same time couple the role of the catalyst to achieve CO2 conversion. Therefore, there is still a need to develop a low-temperature plasma-catalyzed CO2 conversion method with higher conversion rate, more diverse convertible products, and higher selectivity of target products in the conversion products. Summary of the invention

[0004] In view of the characteristics of low-temperature flue gas, the present invention proposes a system for coordinated carbon dioxide capture and in-situ conversion by coupling low-temperature plasma with bifunctional materials having both adsorption and catalytic active sites, thereby achieving a synergistic effect between the two, thereby achieving direct capture and activation of low-concentration CO2 under mild conditions and in-situ catalytic conversion into high-value-added chemicals, avoiding high-temperature CO2 conversion conditions, and solving the bottleneck that the existing technology is difficult to achieve direct CO2 capture and in-situ efficient conversion of low-temperature flue gas under mild conditions.

[0005] In one aspect, the present invention provides a system for low-temperature plasma-coupled bifunctional materials to coordinate carbon dioxide capture and in-situ conversion, comprising a pretreatment unit, a plasma generating 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 materials, wherein the bifunctional materials contain an adsorption component and a catalytic component; the reaction temperature of the carbon capture-conversion integrated unit is 0 to 210°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°C.

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

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

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

[0010] Preferably, the adsorption reaction temperature of the integrated carbon capture-conversion 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 to 90 vol%; more preferably, the carbon dioxide content in the air or industrial flue gas is 0.04 to 30 vol%; more preferably, the carbon dioxide content in the air or industrial flue gas is 0.04 to 20 vol%.

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

[0014] In one or more embodiments, the adsorption component is selected from a combination of one or more 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 catalytic component is selected from a combination of one or more of metals or metal oxides of iron, nickel, cobalt, copper, ruthenium, platinum, palladium, rhodium, and zinc; the mass percentage of the adsorption component in the dual-functional material is 0.1 to 99 wt%, and the mass percentage of the catalytic component in the dual-functional material is 0.1 to 60 wt%.

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

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

[0017] Preferably, the mass percentage of the co-catalytic component in the dual-functional material is 0 to 15 wt %.

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

[0019] The plasma generating unit comprises a high-frequency AC power supply, a voltage controller, an oscilloscope and a high-voltage electrode, wherein the high-voltage electrode is embedded in 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; and the plasma reactor is filled with a dual-function 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 to the carbon capture-conversion integrated unit.

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

[0023] Preferably, the plasma type of the plasma generating unit includes one or more combinations of arc discharge, dielectric barrier discharge, and glow discharge plasma.

[0024] Preferably, the plasma generating unit is composed of a high-voltage electrode, a grounding electrode and an insulating medium; the high-voltage electrode is embedded in a plasma reactor in a carbon capture-conversion integrated unit; the outside of the plasma reactor uses any one of stainless steel, aluminum, copper, molybdenum, tungsten and iron as the grounding electrode; 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 within the range of 50Hz-1MHz.

[0026] Preferably, the shape of the high-voltage electrode in the plasma generating unit is a combination of one or more of blade, rod, arc, and disc; 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 invention provides a method for capturing and converting carbon dioxide in situ using a system as described in any embodiment of the present invention, characterized in that, in the method, a carbon capture-conversion integrated unit captures and converts carbon dioxide in air or industrial flue gas under the action of plasma and reducing gas, specifically comprising the following steps:

[0028] S1: Plasma-induced activation of bifunctional materials: Reducing gas is introduced into the plasma reactor filled with bifunctional materials in the carbon capture-conversion integrated unit. Under the action of plasma, active hydroxyl groups are induced to be generated on the surface of the bifunctional materials, 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 materials are induced to be reduced under low temperature conditions;

[0029] S2: Air / flue gas pretreatment: The air or industrial flue gas input into the system first passes through the dust removal and purification device in the pretreatment unit, and removes fine dust particles in 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 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 pre-treated air or industrial flue gas is introduced into the plasma reactor, and after adsorption treatment by the dual-functional material, low-temperature capture of carbon dioxide is achieved; the decarbonized 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 by controlling the valve, and the captured carbon dioxide is converted in-situ under the catalysis of the dual-functional material and the action of plasma to generate product gas containing the target product;

[0032] S5: Product gas separation and purification: The product gas enters the condensing device and separation device in the separation-purification unit in turn, collects the separated target product, and controls the valve to re-enter the separated incompletely reacted raw gas into the raw gas pipeline for recycling.

[0033] In one or more embodiments, the feed 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 entering the plasma reactor; the time for inducing activation of the dual-functional material is 1 min to 10 h.

[0035] Preferably, in step S1, the induction activation time of the dual-functional material is 4 minutes to 7 hours.

[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 10,000 h -1 .

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

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

[0039] In one or more embodiments, the plasma reactor is a multistage parallel plasma fixed bed reactor, wherein the multistage parallel plasma fixed bed reactor is a dual parallel plasma fixed bed reactor; when the carbon dioxide adsorption amount of the dual-functional material in one of the reactors reaches saturation, the plasma generating unit corresponding to the reactor is started, and the raw gas is introduced into the reactor through the control valve for in-situ conversion, and at the same time, air or industrial flue gas is introduced into the other reactor for carbon dioxide adsorption.

[0040] In one or more embodiments, the plasma reactor is a circulating plasma fluidized bed reactor, including an adsorption reactor and a conversion reactor; when the carbon dioxide adsorption of the dual-function material in the adsorption reactor reaches saturation, a cyclone separator is used to separate the dual-function materials in the adsorption reactor and the conversion reactor, and then enter the two reactors through pipelines to realize the circulation of the dual-function materials in the two reactors. In another aspect, the present invention provides an application of a system as described in any embodiment of the present invention in carbon dioxide capture and in-situ conversion.

[0041] The present invention provides a system and method for low-temperature plasma-coupled dual-functional materials to coordinate carbon dioxide capture and in-situ conversion. On the one hand, the carbon capture-conversion integrated unit is filled with an adsorption / catalysis dual-functional material with high carbon dioxide adsorption capacity and high catalytic activity. The catalytic active component and the co-catalytic component in the material are highly dispersed on an adsorption component substrate with a porous structure, so that CO2 can be effectively combined with adjacent metal catalytic active sites after being adsorbed and fixed, greatly improving the catalytic activity of the reaction, thereby improving the CO2 conversion efficiency, and the porous structure fully exposes the catalytic active sites, which is also conducive to the diffusion of reactants and products, thereby achieving carbon dioxide capture and in-situ conversion at the same temperature; on the other hand, the present invention couples plasma with the dual-functional material, and uses the high-energy electrons in the low-temperature plasma to activate the catalytic active centers of the introduced reducing gas in the dual-functional material adsorption-catalysis reaction interface through ionization, excitation and dissociation to generate active hydrogen species. The hydrogen species generated at the metal catalytic active sites directly react with the adjacent adsorbed CO2 molecules through hydrogen overflow, and the target product can be generated with high conversion rate and high selectivity under low temperature and normal pressure conditions. By taking advantage of the above two effects, the present invention avoids the harsh conditions of high temperature and high pressure in the conventional production of methanol and olefins and the high temperature requirement for the production of synthesis gas and methane. It also avoids the temperature difference contradiction between low-temperature air or industrial flue gas carbon capture and high-temperature carbon conversion process, thereby greatly reducing energy consumption.

[0042] In addition, the system equipment provided in the present invention has low cost, short process flow, simple and easy operation and control, and is expected to solve the high costs in the current CO2 capture, separation, purification and transportation processes, as well as the low efficiency and high energy consumption of CO2 conversion. At the same time, it can also produce high value-added products, providing a technical solution for the capture and utilization of low-temperature flue gas CO2 in the industrial field. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a system process diagram for low-temperature plasma coupled dual-functional materials for synergistic carbon dioxide capture and in-situ conversion.

[0044] Figure 2 A multi-stage fixed-bed parallel process flow chart for a system of low-temperature plasma coupled dual-functional materials for synergistic carbon dioxide capture and in-situ conversion.

[0045] Figure 3 Circulating fluidized bed process flow diagram for the system of low-temperature plasma coupled dual-functional materials for synergistic carbon dioxide capture and in-situ conversion. DETAILED DESCRIPTION

[0046] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

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

[0048] The "dual-function material" in the present invention is a material that has the functions of both adsorbing CO2 and catalyzing the conversion of CO2 into a target product, which includes an adsorption component, a catalytic component, and may further include a co-catalytic component. The adsorption component may be selected from a combination of one or more of hydrotalcite, zeolite, activated carbon, modified ion resin, calcium oxide, magnesium oxide, solid-loaded amino, sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide; the mass percentage of the adsorption component in the dual-function material is 0.1 to 99wt%. The catalytically active component may be selected from a combination of one or more of the 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-function material is 0.1 to 60wt%. The co-catalytic component may be selected from a combination of one or more of cerium, potassium, sodium, phosphorus, and nitrogen; the mass percentage of the co-catalytic component in the dual-function material is 0 to 20wt%.

[0049] In the present invention, before the "dual-functional material", "adsorption component" or "catalytic component" is used for CO2 adsorption and in-situ conversion in air or industrial flue gas, the "CO2 adsorption amount" is measured in advance using a CO2 infrared analyzer. The CO2 adsorption amount is calculated by detecting the outlet concentration of the decarbonized flue gas using a CO2 infrared analyzer and calculating it using formula (I):

[0050]

[0051] in is the molar flow rate of CO2 in the inlet air or flue gas, is the molar flow rate 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 materials

[0053] Preparation or acquisition of adsorption components:

[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 of deionized water, stirred evenly and transferred to 100mL polytetrafluoroethylene liner and sealed, and hydrothermaled at 150°C for 10h; after the hydrothermal is completed, the liquid is cooled to room temperature and filtered, and the obtained white precipitate is washed with deionized water several times and dried at 70°C for 12h to obtain MgAl-LDH.

[0055] Acquisition of other adsorption components: zeolite, activated carbon, modified ion resin, calcium oxide, magnesium oxide, solid-supported amino, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide and other adsorption components can be obtained commercially.

[0056] General preparation method of bifunctional material: The bifunctional material in the present invention is prepared by an impregnation method, that is, the adsorption component is used as a carrier, and a salt solution of the catalytic component (and the co-catalytic component) with a corresponding content is impregnated, and the mixture is obtained after filtering, washing, and roasting. If not otherwise specified, the general specific preparation method of the bifunctional material in the present invention is as follows: First, according to the target metal loading mass fraction, weigh 0.1 to 5.0 g of a solid salt corresponding to the catalytic component (including but not limited to chlorides (such as ferric chloride, nickel chloride, cobalt chloride, copper chloride, ruthenium chloride, platinum chloride, chloroplatinic acid, palladium chloride, zinc chloride), nitrates (such as ferric nitrate, nickel nitrate, cobalt nitrate, copper nitrate, ruthenium nitrate, platinum nitrate, palladium nitrate, rhodium nitrate, zinc nitrate), acetates (such as ferric acetate, nickel acetate, cobalt acetate, copper acetate, ruthenium acetate, platinum acetate, palladium acetate, rhodium acetate, zinc acetate), sulfates (such as ferric sulfate, nickel sulfate, Cobalt sulfate, copper sulfate, zinc sulfate) and 0-1.5g of solid salt corresponding to the promoter component (including but not limited to chlorides (such as cerium chloride, potassium chloride, sodium chloride), nitrates (such as cerium nitrate, potassium nitrate, sodium nitrate), urea, phosphates (such as potassium phosphate, sodium phosphate), carbonates (such as sodium carbonate, potassium carbonate)) are dissolved in 100-200mL of aqueous solution and stirred evenly; then 3.5-9.0g of the adsorption carrier is weighed and added to the above mixed solution and stirred and dispersed evenly, and 0-5mL of ammonia water is added dropwise, and then stirred and immersed at 25-100°C for 3-12h; after stirring, filter, wash the filtered solid repeatedly with water for 2-3 times, dry at 80°C overnight, and calcine from room temperature to 320-450°C in an air atmosphere for 3-5h (heating rate is 5°C / min) to obtain the corresponding adsorption-carrier dual-functional material, and granulate with 40-60 mesh.

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

[0058] According to the target metal loading mass fraction, 2.72g of nickel nitrate and cobalt nitrate corresponding to the catalytic components and 0.23g of potassium nitrate corresponding to the co-catalyst component were weighed and dissolved in 100mL of aqueous solution and stirred evenly; then 7.05g of LDH adsorption carrier was added to the above mixed solution and stirred. After the mixed solution was heated to 70°C, 5mL of ammonia water was added and stirred and immersed for 3h, and then filtered. The filtered solid was washed with water 2-3 times and dried at 80°C overnight; the solid was air roasted at 450°C for 3h (the heating rate of the roasting equipment was 5°C / min) to obtain 10g of NiCo / K / LDH dual-functional material, which was granulated with 40-60 mesh.

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

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

[0061] Preparation of Cu / Ce / CaO dual-functional materials:

[0062] According to the target metal loading mass fraction, 0.31 g of copper sulfate corresponding to the catalytic component and cerium nitrate corresponding to the co-catalytic component were weighed and dissolved in 150 mL of aqueous solution and stirred evenly; 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 hours, then filtered, and the filtered solid was washed with water 2 to 3 times and dried at 80°C overnight; the solid was air-roasted at 450°C for 5 hours (the heating rate of the roasting equipment was 5°C / min) to obtain 10 g of Cu / Ce / CaO dual-functional material, which was granulated with 40 to 60 mesh.

[0063] Preparation of FeCo / K2CO3 / molecular sieve (or FeCo / Na2CO3 / molecular sieve) dual-function material:

[0064] According to the target metal loading mass fraction, 4.02 g of ferric chloride, cobalt chloride, potassium carbonate or sodium carbonate corresponding to the catalytic component was weighed (dissolved in 130 mL of aqueous solution and stirred evenly; then 4.02 g of zeolite adsorption carrier was dispersed into the above mixed solution, 5 mL of ammonia water was added at 50 ° C. and stirred and immersed for 9 hours, then filtered, and the filtered solid was washed with water 2 to 3 times, dried at 80 ° C. overnight, and air-roasted at 400 ° C. for 5 hours (heating rate of 5 ° C. / min) to obtain 10 g of FeCo / K2CO3 / molecular sieve (or FeCo / Na2CO3 / molecular sieve) bifunctional material, which was granulated with 40 to 60 mesh.

[0065] Preparation of FeNi / N / activated carbon (or FeNi / N / MgO) dual-functional materials:

[0066] According to the target metal loading mass fraction, 3.0 g of iron nitrate and nickel nitrate corresponding to the catalytic component and 1.0 g of urea corresponding to the co-catalytic component were weighed and dissolved in 180 mL of aqueous solution and stirred evenly; then 6.0 g of activated carbon (or magnesium oxide) adsorption carrier was dispersed into the above mixed solution, 2 mL of ammonia water was added at 60°C and stirred and immersed for 4 hours, then filtered, and the filtered solid was washed with water 2 to 3 times and dried at 80°C overnight; the solid was air-roasted at 400°C for 3 hours (the heating rate of the roasting equipment was 5°C / min) to obtain 10 g of FeNi / N / activated carbon (or FeNi / N / MgO) dual-functional material, and granulated with 40 to 60 mesh.

[0067] Preparation of RhNi / Na / ion resin dual-functional material:

[0068] According to the target metal loading mass fraction, 5.0g of rhodium chloride and nickel chloride corresponding to the catalytic components and 0.05g of sodium chloride as a co-catalyst were weighed and dissolved in 100mL of aqueous solution and stirred evenly; then 4.95g of the ion resin adsorption carrier was dispersed into the above mixed solution, 5mL of ammonia water was added at 25°C and stirred and immersed for 12h, then filtered, and the filtered solid was washed with water 2-3 times and dried at 80°C overnight; the solid was air-roasted at 300°C for 3h (the heating rate of the roasting equipment was 5°C / min) to obtain 10g of RhNi / Na / ion resin dual-functional material, which was granulated with 40-60 mesh.

[0069] Preparation of CuZn / Ce / NH2-molecular sieve (amino-grafted molecular sieve) dual-functional material:

[0070] According to the target metal loading mass fraction, 2.81g of copper nitrate and zinc chloride corresponding to the catalytic components and 1.5g of cerium nitrate corresponding to the co-catalyst component were weighed and dissolved in 200mL of aqueous solution and stirred evenly; then 5.69g of ion resin adsorption carrier was dispersed into the above mixed solution, 2mL of ammonia water was added at 25°C and stirred and immersed for 8h, then filtered, and the filtered solid was washed with water 2-3 times and dried at 80°C overnight; the solid was air roasted at 200°C for 3h (the heating rate of the roasting equipment was 5°C / min) to obtain 10g of CuZn / Ce / NH2-molecular sieve bifunctional material, which was granulated with 40-60 mesh.

[0071] Preparation of Co / Na-K / activated carbon dual-functional materials:

[0072] According to the target metal loading mass fraction, 5.0 g of cobalt sulfate corresponding to the catalytic component and 1.0 g of KOH and NaOH corresponding to the co-catalytic component were weighed and dissolved in 140 mL of aqueous solution and stirred evenly; then 4.0 g of the activated carbon adsorption carrier was dispersed into the above mixed solution, stirred and immersed at 90°C for 8 hours, filtered, and the filtered solid was washed with water 2 to 3 times and dried at 80°C overnight; the solid was air roasted at 250°C for 3 hours (the heating rate of the roasting equipment was 5°C / min) to obtain 10 g of Co / Na-K / activated carbon dual-functional material, and granulated with 40 to 60 mesh.

[0073] Example 2: Low-temperature plasma coupled dual-functional materials for coordinated carbon dioxide capture and in-situ conversion system and process flow

[0074] like Figure 1 As shown, the system of low-temperature plasma coupled dual-functional materials for coordinated carbon dioxide capture and in-situ conversion in this 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 and purification device and a temperature control module, which are used to pretreat the air or industrial flue gas; wherein the dust removal and purification device is used to purify the fine particle dust of the air or industrial flue gas, deeply remove the fine particles, avoid clogging the reactor in the subsequent carbon capture-conversion integrated unit or affecting the catalytic performance of the dual-functional material, for example, specifically, one or a combination of electrostatic dust removal and mechanical dust removal equipment can be used; the temperature control module is used to adjust the temperature of the air or industrial flue gas to meet the requirements of the adsorption reaction temperature and the conversion reaction temperature. The pretreatment unit 1 is connected to 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 includes a high-frequency AC power supply, a voltage controller, an oscilloscope and a high-voltage electrode, which are used to generate the plasma required for adsorption and conversion; wherein the high-frequency AC power supply is used to output AC power, the oscilloscope is used to observe the voltage, the voltage controller is used to control and stabilize the voltage, and the high-voltage electrode is used to carry the voltage generated by the high-frequency AC power supply and generate plasma. The high-frequency AC power supply, the voltage controller, the oscilloscope and the high-voltage electrode are all conventional equipment in the art, and their connection methods are also conventional means in the art, so they are not described in detail here.

[0077] The carbon capture-conversion integrated unit 3 includes a plasma reactor, a program flow regulating valve and a temperature control module, which is used to perform low-temperature capture and in-situ conversion of carbon dioxide in air or industrial flue gas; the plasma reactor is filled with a bifunctional material; the bifunctional material couples the effect 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, and is used to generate plasma in the plasma reactor.

[0078] The product separation-purification unit 4 includes a condensing device and a separation device, which is used to separate and purify the product flowing out of the carbon capture-conversion integrated unit 3, and separate the target product and the raw gas that has not reacted completely; wherein the raw gas that has not reacted completely re-enters 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 to the carbon capture-conversion integrated unit 3.

[0079] Using the above system, the process of capturing and converting carbon dioxide from air or industrial flue gas in situ mainly includes five steps:

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

[0081] S2: Air / flue gas pretreatment: The air or industrial flue gas input into the system first passes through the dust removal and purification device in the pretreatment unit, and removes fine particles of dust in 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 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 after adsorption treatment by dual-functional materials, low-temperature capture of carbon dioxide is achieved; the decarbonized 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 by controlling the valve, and the carbon dioxide is converted in-situ under the catalysis of the bifunctional material and the action of plasma to generate a product gas containing the target product.

[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 sequence, collects the separated target product, and controls the valve to re-enter the separated incompletely reacted raw gas into the raw gas pipeline for recycling.

[0085] According to the different reactor forms of the carbon capture-conversion integrated unit 3, a plasma fixed bed and a plasma fluidized bed are used to realize a continuous process, see Example 3 and Example 4 for details.

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

[0087] Each unit component: This embodiment adopts a multi-stage plasma fixed bed parallel system ( Figure 2 ), the time of the adsorption and conversion process is matched, and a dual fixed bed plasma reactor is used; if the time of the adsorption and conversion process is matched, a multi-stage plasma fixed bed parallel process with three reactors or more can also be used. This embodiment takes the process of a dual fixed bed plasma reactor as an example, but its scope is not limited to dual fixed bed reactors in parallel. The dual 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 control valves V1, V10, V11, flow three-way valves V2, V3, V4, V5, V6, V7, V8, V9, plasma fixed bed reactors R1, R2, high voltage power supply E1, voltage controller F2, oscilloscope F3, high voltage electrode F1, condensation device D1, separation device P1.

[0088] Process flow: Both plasma fixed bed reactors R1 and R2 are filled with adsorption / catalysis dual-functional materials, which participate in adsorption and conversion in the system; R1 and R2 are connected in parallel, and the two switch between air or industrial flue gas carbon dioxide capture and in-situ conversion. First, open the program flow control valve V10, adjust the three-way valves V2, V3, V4, and V5 to pass the reducing gas, and the reducing gas passes through the preheater H1 to reach the adsorption reaction temperature and then enters R1 and R2; start the plasma generating unit to induce activation of the dual-functional materials in R1 and R2 in the reducing gas atmosphere. After the induced activation is completed, the low-temperature flue gas after air or industrial desulfurization and denitrification is transported into the system through the program flow control valve V1, pre-treated by the dust removal and purification device S1, and the temperature of the air or industrial flue gas is adjusted by the built-in temperature control module of the unit; by controlling the program flow control valves V2, V3, V4, and V5, the switching between inputting the pre-treated air or industrial flue gas into R1 and inputting 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, and V5, the raw gas is switched between being input into R1 and being input into R2; 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, and V9, the decarbonized flue gas after adsorption treatment is switched between flowing out and emptying from the reactor R1 and flowing out and emptying from the reactor R2. By controlling the program flow regulating valves V6, V7, V8, and V9, the product gas generated by the conversion is switched between flowing out and collecting from the reactor R1 and flowing out and collecting from the reactor R2. The product gas enters the condensing device D1 and the separation device P1 in turn for separation and purification, and the separated unreacted raw gas is re-entered into the raw gas pipeline for recycling through the program flow control valve V11.

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

[0090] Reactors R1 and R2 are filled with NiCo / K / LDHs bifunctional materials with bimetallic NiCo and catalytic K loaded on the substrate of hydrotalcite (LDH). After plasma-induced activation of the material, the CO2 adsorption capacity of the bifunctional material reaches 3-5mmol / kg; the raw flue gas is the flue gas after desulfurization and denitrification of coal-fired power plants, with a temperature of 70-90°C and a carbon dioxide content of 7-15vol%; the flue gas volume space velocity entering the system is controlled to be maintained at 2000h -1 , the hydrogen volume space velocity is 1000h -1; The adsorption reaction and conversion reaction 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 and conversion reaction temperature. First, open the program flow control valve V10, adjust the three-way valves V2, V3, V4, and V5 to introduce hydrogen, and the hydrogen is heated to the adsorption reaction and conversion reaction temperature through the preheater H1. At the same time, start the plasma generating unit, adjust the frequency of 50Hz and the discharge power of 10W, and induce the activation of the dual-functional materials in R1 and R2 for 5 to 7 hours; after the induction activation is completed, turn off the plasma generating unit; transport the flue gas into the system through the flow control valve V1, and the air or industrial flue gas enters the dust removal and purification device S1 for pretreatment. The flue gas temperature is controlled to be the same as the adsorption reaction and conversion reaction temperature through the built-in temperature control module of the dust removal and purification device; adjust the three-way flow control valves V2, V3, V4, and V5 to allow the flue gas to enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the dual-functional material; adjust the three-way flow control valves V6, V7, V8, and V9 to allow the decarbonized flue gas in R1 to be directly discharged through the three-way flow control valves V6 and V8 in turn after adsorption treatment. When the CO2 adsorption of the bifunctional material in the reactor R1 reaches saturation, the three-way flow regulating valves V2, V3, V4, and V5 are adjusted to switch the flue gas input to R2 for CO2 adsorption, and the plasma generating unit in R1 is started at the same time, and the frequency is adjusted to 50Hz and the discharge power is 100W; hydrogen is transported into the system through the flow regulating valve V10, and is preheated to the adsorption reaction and conversion reaction temperature by the preheater H1. The three-way flow regulating valves V2, V3, V4, and V5 are adjusted to allow hydrogen to enter the reactor R1, and the adsorbed CO2 is converted in situ into the target product crude methanol; the three-way flow regulating valves V6, V7, V8, and V9 are adjusted to allow the crude methanol product in R1 to pass through R6 and R9 in turn, and then enter D1 of the condensing device and the separation device P1 (gas-liquid separation device) in turn. The methanol is collected as a product after condensation and liquefaction, and the separated unreacted hydrogen is reused through the flow regulating valve V11. Similarly, when the CO2 adsorbed by the bifunctional material in R2 reaches saturation, the corresponding three-way flow control valve is adjusted to discharge the decarbonized 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 is used to switch the adsorption and reduction cycles between fixed bed reactors, which can achieve a flue gas carbon dioxide capture rate of more than 95%, an adsorbed CO2 conversion rate of more than 90%, and a methanol selectivity of more than 90% in the product.

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

[0092] Reactors R1 and R2 are filled with bifunctional materials of RuPt / P / zeolite (or RuPd / P / zeolite) with bimetallic RuPt (or RuPd) and catalytic P as substrates. After plasma-induced activation of the material, the CO2 adsorption capacity of the bifunctional material reaches 2-3 mmol / kg; the raw flue gas is room-temperature flue gas from a coal-fired power plant after desulfurization and denitrification, with a carbon dioxide content of 3-10 vol%; the flue gas volume space velocity introduced into the system is controlled to be maintained at 10,000 h -1 , hydrogen volume space velocity at 10000h -1; The temperature of the adsorption reaction and the conversion reaction is 15 to 35°C, preferably 25°C; the temperature of the reactors R1 and R2 is controlled to be the same as the temperature of the adsorption reaction and the conversion reaction. First, open the program flow control valve V10, adjust the three-way valves V2, V3, V4, and V5 to introduce hydrogen, and the hydrogen is heated to the adsorption reaction and conversion reaction temperature through the preheater H1. At the same time, start the plasma generating unit, adjust the frequency of 1MHz and the discharge power of 5kW, and induce the activation of the dual-functional materials in R1 and R2 for 4 to 6 minutes; after the induction activation is completed, turn off the plasma generating unit; transport the flue gas at room temperature into the system through the flow control valve V1, and the air or industrial flue gas enters the dust removal and purification device S1 for pretreatment. The flue gas temperature is controlled to be the same as the adsorption reaction and conversion reaction temperature through the built-in temperature control module of the dust removal and purification device; adjust the three-way flow control valves V2, V3, V4, and V5 to allow the flue gas to enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the dual-functional material; adjust the three-way flow control valves V6, V7, V8, and V9 to allow the decarbonized flue gas in R1 to be directly discharged through the three-way flow control valves V6 and V8 in sequence after adsorption treatment. When the CO2 adsorption of the bifunctional material in the reactor R1 reaches saturation, the three-way flow regulating valves V2, V3, V4, and V5 are adjusted to switch the flue gas input to R2 for CO2 adsorption, and at the same time, the plasma generating unit in R1 is started, and the frequency is adjusted to 1MHz and the discharge power is 5000W; hydrogen is transported into the system through the flow regulating valve V10, and the three-way flow regulating valves V2, V3, V4, and V5 are adjusted to allow hydrogen to enter the reactor R1, and the adsorbed CO2 is converted in situ into the target product crude methane; the three-way flow regulating valves V6, V7, V8, and V9 are adjusted to allow the crude methane product in R1 to pass through R6 and R9 in turn, and then enter D1 of the condensing device and P1 (pressure swing adsorption device) of the separation device in turn, and methane is collected as a product, and the separated unreacted hydrogen is reused through the flow regulating valve V11. Similarly, when the CO2 adsorbed by the bifunctional material in R2 reaches saturation, the corresponding three-way flow control valve is adjusted to discharge the decarbonized flue gas in R2, and the plasma generating unit in R2 is started to introduce hydrogen into R2, and the methane produced in R2 is collected, and then the flue gas is input into R1 for CO2 adsorption. In summary, the system is used to switch the adsorption and reduction cycles between fixed bed reactors, which can achieve a flue gas carbon dioxide capture rate of more than 93%, an adsorbed CO2 conversion rate of more than 95%, and a methane selectivity of more than 99% in the product.

[0093] 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:

[0094] Reactors R1 and R2 are filled with Cu / Ce / CaO bifunctional materials with porous calcium oxide (CaO) as the substrate to load single metal Cu and catalytic Ce. 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 after desulfurization and denitrification of coal-fired power plants, with a temperature of 140-160°C and a carbon dioxide content of 18-20 vol%; the flue gas volume space velocity entering the system is controlled to be maintained at 100h -1 , the hydrogen volume space velocity is 100h -1 , methane volume space velocity at 100h -1; The adsorption reaction and conversion reaction temperature is 190-210°C, preferably 200°C; the temperature of reactors R1 and R2 is controlled to be the same as the adsorption reaction and conversion reaction temperature. First, open the program flow control valve V10, adjust the three-way valves V2, V3, V4, and V5 to introduce hydrogen, and the hydrogen is heated to the adsorption reaction and conversion reaction temperature through the preheater H1. At the same time, start the plasma generating unit, adjust the frequency of 5000 Hz and the discharge power of 2.5 kW, and induce the activation of the dual-functional materials in R1 and R2 for 2 to 4 hours; after the induction activation is completed, close the plasma generating unit, and transport the flue gas into the system through the flow control valve V1, and the air or industrial flue gas enters the dust removal and purification device S1 for pretreatment. The flue gas temperature is controlled to be the same as the adsorption reaction and conversion reaction temperature through the built-in temperature control module of the dust removal and purification device; adjust the three-way flow control valves V2, V3, V4, and V5 to allow the flue gas to enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the dual-functional material; adjust the three-way flow control valves V6, V7, V8, and V9 to allow the decarbonized flue gas in R1 to be directly discharged through the three-way flow control valves V6 and V8 in sequence after adsorption treatment. When the bifunctional material in the reactor R1 is saturated with adsorption, the three-way flow regulating valves V2, V3, V4, and V5 are adjusted to switch to flue gas input to R2 for CO2 adsorption, and the plasma generating unit is started at the same time, the frequency is adjusted to 5000Hz, and the discharge power is 2500W; methane is transported into the system through the flow regulating valve V10, and is preheated to the adsorption reaction and conversion reaction temperature by the preheater H1. The three-way flow regulating valves V2, V3, V4, and V5 are adjusted to allow methane to enter the reactor R1, and the adsorbed CO2 is converted in situ into the target product crude synthesis gas; the three-way flow regulating valves V6, V7, V8, and V9 are adjusted to allow the crude methane product in R1 to 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 to produce a synthesis gas with a hydrogen-carbon molar ratio of 3. The synthesis gas is collected as a product, and the separated unreacted methane is recycled through the flow regulating valve V11. Similarly, when the CO2 adsorbed by the bifunctional material in R2 reaches saturation, the corresponding three-way flow control valve is adjusted to discharge the decarbonized flue gas in R2, and the plasma generating unit in R2 is started to introduce methane into R2, and the synthesis gas generated in R2 is collected, and then the flue gas is input into R1 for CO2 adsorption. In summary, the system is used to switch the adsorption and reduction cycles between fixed bed reactors, which can achieve a flue gas carbon dioxide capture rate of more than 99%, an adsorbed CO2 conversion rate of more than 97%, and a selectivity of more than 95% for the synthesis gas in the product.

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

[0096] Reactors R1 and R2 are filled with FeCo / K2CO3 / molecular sieve (or FeCo / Na2CO3 / molecular sieve) bifunctional materials with molecular sieve-loaded potassium carbonate (or sodium carbonate) and bimetallic FeCo as adsorption sites. After plasma-induced activation of the material, the CO2 adsorption 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 be maintained at 5000h -1 , hydrogen volume space velocity at 5000h -1; The adsorption reaction and conversion reaction temperature is 90-110°C, preferably 100°C; the temperature of reactors R1 and R2 is controlled to be the same as the adsorption reaction and conversion reaction temperature. First, open the program flow control valve V10, adjust the three-way valves V2, V3, V4, and V5 to introduce hydrogen, and the hydrogen is heated to the adsorption reaction and conversion reaction temperature through the preheater H1. At the same time, start the plasma generating unit, adjust the frequency of 2500Hz and the discharge power of 1kW, and induce the activation of the dual-functional materials in R1 and R2 for 0.5 to 1.5h; after the induction activation is completed, turn off the plasma generating unit, adjust the frequency to 200W, the current to 10A, and the voltage to 20V; transport the flue gas into the system through the flow control valve V1, enter the dust removal and purification device S1 for pretreatment, and adjust the air or industrial flue gas temperature to the adsorption reaction and conversion reaction temperature through the built-in temperature control module of the unit; adjust the three-way flow control valves V2, V3, V4, and V5 to allow the flue gas to enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the dual-functional material; adjust the three-way flow control valves V6, V7, V8, and V9 to allow the decarbonized flue gas in R1 to be directly discharged through the three-way flow control valves V6 and V8 in sequence after adsorption treatment. When the bifunctional material in the reactor R1 is saturated with adsorption, the three-way flow regulating valves V2, V3, V4, and V5 are adjusted to switch the flue gas input to R2 for CO2 adsorption, and the plasma generating unit in R1 is started at the same time, and the frequency is adjusted to 1000Hz and the discharge power is 200W; hydrogen is transported into the system through the flow regulating valve V10, and is preheated to the adsorption reaction and conversion reaction temperature by the preheater H1. The three-way flow regulating valves V2, V3, V4, and V5 are adjusted to allow hydrogen to enter the reactor R1, and the adsorbed CO2 is converted in situ into the target product crude olefin; the three-way flow regulating valves V6, V7, V8, and V9 are adjusted to allow the crude olefin product in R1 to pass through R6 and R9 in turn, and then enter the condensation device D1 and the separation device P1 (pressure swing adsorption device) in turn. The olefin is collected as a product, and the separated unreacted hydrogen is reused through the flow regulating valve V11. Similarly, when the CO2 adsorbed by the bifunctional material in R2 reaches saturation, the corresponding three-way flow control valve is adjusted to discharge the decarbonized flue gas in R2, and the plasma generating unit in R2 is started to introduce hydrogen into R2, and the olefins produced in R2 are 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 more than 96%, an adsorbed CO2 conversion rate of more than 94%, and a selectivity of olefins in the product of more than 90%.

[0097] Some parameters of the above Example 3 are summarized in the following Table 1 for easy reading and analysis.

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

[0099]

[0100] Example 4: Continuous CO2 low-temperature 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 ), including a circulating plasma fluidized bed system including a pretreatment unit (V1, S1, H1), a plasma generating 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 control valves V1, V2, V3, V4, cyclone separators C1, C2, high voltage power supply E1, voltage controller F2, oscilloscope F3, high voltage electrode F1, preheater H1, condensation device D1, separation device P1.

[0102] Process flow: The dual fluidized beds in the system are conversion reactor R1 and adsorption reactor R2 respectively. The system realizes continuous air or industrial flue gas carbon dioxide capture and in-situ conversion through the adsorption / catalysis dual-functional material particle circulation. First, open the program flow control valves V2 and V4, close the flow control valves V1 and V3 to pass the reducing gas, and the hydrogen is heated to the adsorption reaction temperature through the preheater H1. At the same time, start the plasma generation unit to induce activation of the dual-functional material; after the induction activation is completed, close the flow control valve V4, and transport the air or industrial flue gas into the system through the program flow control valve V1. The air or industrial flue gas enters the dust removal and purification device S1 for pretreatment, and the temperature of the air or industrial flue gas is adjusted by the built-in temperature control module of 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 control 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, start the plasma generation unit to generate plasma in the reactor to catalyze the conversion of the adsorbed carbon dioxide in situ. Gas-solid cyclone separators C1 and C2 are used to separate the dual-functional material particles from the product gas and the decarbonized flue gas, respectively, so that the dual-functional material particles circulate between the adsorption reactor R2 and the conversion reactor R1; the separated decarbonized flue gas flowing out of the adsorption reactor R2 is directly discharged; the separated product gas flowing out of the conversion reactor R1 enters the condensing device D1 and the separation device P1 in turn for separation and purification, and the separated unreacted raw gas methane or hydrogen is re-entered into the raw gas pipeline for recycling through the program flow control valve V3.

[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] Reactors R1 and R2 are filled with FeNi / N / activated carbon (or FeNi / N / MgO) bifunctional materials that use activated carbon (or magnesium oxide) as an adsorption carrier and load bimetallic FeNi and additive N. After 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 from a coal-fired power plant after desulfurization and denitrification, with a temperature of 120°C and a carbon dioxide content of 7-15 vol%; the flue gas volume space velocity entering the system is controlled to be maintained at 5000h -1 , hydrogen volume space velocity at 2000h -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, open the flow control valves V2 and V4, close the flow control valves V1 and V3 to introduce hydrogen, and start the plasma generation unit, adjust the frequency of 100Hz and the discharge power of 50W, and induce the activation of the dual-functional materials in R1 and R2 for 5-7h; After the induced activation is completed, close the plasma generation unit, close the flow control valve V4, and transport the flue gas into the system through the flow control valve V1. The air or industrial flue gas enters the dust removal and purification device S1 for pretreatment, and the flue gas temperature is controlled to the adsorption reaction temperature by the built-in temperature control module; 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, and the hydrogen is transported into the system through the program flow control 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 3000Hz, and the discharge power is 1000W, and the carbon dioxide adsorbed by in-situ catalysis is converted. The gas-solid cyclone separators C1 and C2 are respectively used to separate the dual-functional material particles from the product gas and the decarbonized flue gas, so that the dual-functional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The separated decarbonized flue gas flowing out of the adsorption reactor R2 is directly discharged. The separated crude synthesis gas flowing out of the conversion reactor R1 enters the condensation device D1 to remove the condensed water, and then enters the separation device P1 (pressure swing adsorption device) to separate and purify the excess hydrogen by low-temperature pressure swing adsorption to ensure that the hydrogen-carbon molar ratio in the product synthesis gas is close to 2; the separated unreacted raw gas hydrogen enters the raw gas pipeline for recycling through the program flow control valve V3. In summary, the system can achieve a carbon dioxide capture rate in flue gas greater than 95%, an adsorbed CO2 conversion rate greater than 90%, and a syngas selectivity of nearly 99% in the product.

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

[0106] Reactors R1 and R2 are filled with RhNi / Na / ion resin bifunctional materials with modified ion resin as adsorption carrier grafted with RhNi and auxiliary agent Na. 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 the air is 0.04 vol%; the volume space velocity of the room temperature air introduced into the system is controlled to be maintained at 8000 h -1 , hydrogen volume space velocity at 8000h -1 ; The adsorption temperature is 15-35°C, preferably 25°C; the conversion temperature is 70-90°C, preferably 80°C, and the temperature of the reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, open the flow control valves V2 and V4, close the flow control valves V1 and V3 to introduce hydrogen, and start the plasma generating unit, adjust the frequency of 1000Hz and the discharge power of 2000W, and induce the activation of the dual-functional materials in R1 and R2 for 2-4h; after the induced activation, close the plasma generating unit, close the flow control valve V4, and transport the room temperature air into the system through the program flow control valve V1, and the air enters the dust removal and purification device S1 for pretreatment, and the air temperature is controlled to the adsorption reaction temperature by the built-in temperature control module; 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, and the hydrogen is transported into the system through the program flow control 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 1500Hz, and the discharge power is 500W, and the carbon dioxide conversion by in-situ catalytic adsorption is carried out. The gas-solid cyclone separators C1 and C2 are respectively used to separate the dual-functional material particles from the product gas and the decarbonized air, so that the dual-functional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The separated decarbonized air flowing out of the adsorption reactor R2 is directly emptied. The separated crude synthesis gas flowing out of the conversion reactor R1 enters the condensation device D1 to remove the condensed water, and then enters the separation device P1 (pressure swing adsorption device) to separate and purify the excess hydrogen through low-temperature pressure swing adsorption to ensure that the hydrogen-carbon molar ratio in the product synthesis gas is close to 3; the separated unreacted raw gas hydrogen enters the raw gas pipeline for recycling through the program flow control valve V3. In summary, the system can achieve a carbon dioxide capture rate of more than 98% in the air, an adsorbed CO2 conversion rate of more than 96%, and a methane selectivity of nearly 98% in the product.

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

[0108] Reactors R1 and R2 are filled with CuZn / Ce / NH2-molecular sieve bifunctional materials impregnated with CuZn and Ce as adsorbent using amino-grafted molecular sieve as adsorption carrier. 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 the flue gas after desulfurization and denitrification from a coal-fired power plant, with a temperature of 70-90°C and a carbon dioxide content of 12-15 vol%. The volumetric space velocity of the flue gas introduced into the system is controlled to be maintained at 4000 h -1 , hydrogen volume space velocity at 5000h -1 ; The adsorption temperature is 70-90°C, preferably 80°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, open the flow control valves V2 and V4, close the flow control valves V1 and V3 to introduce hydrogen, and start the plasma generating unit, adjust the frequency of 800Hz and the discharge power of 500W, and induce the activation of the dual-functional materials in R1 and R2 for 4-6 hours; After the induced activation is completed, close the plasma generating unit, close the flow control valve V4, and transport the flue gas into the system through the flow control valve V1. The flue gas enters the dust removal and purification device S1 for pretreatment, and the flue gas temperature is controlled to the adsorption reaction temperature by the built-in temperature control module; The pretreated 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, and the hydrogen is transported into the system through the program flow control 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 2000Hz, and the discharge power is 1200W, and the carbon dioxide conversion by in-situ catalytic adsorption is carried out. The gas-solid cyclone separators C1 and C2 are respectively used to separate the dual-functional material particles from the product gas and the decarbonized flue gas, so that the dual-functional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The separated decarbonized flue gas flowing out of the adsorption reactor R2 is directly emptied. The separated crude methanol flowing out of the conversion reactor R1 enters the condensation device D1 to remove the condensed water, and then enters the separation device P1 (gas-liquid separation device) to purify the excess hydrogen by gas-liquid separation; the separated unreacted raw gas hydrogen enters the raw gas pipeline for recycling through the program flow control valve V3. In summary, the use of this system can achieve a flue gas carbon dioxide capture rate greater than 95%, an adsorbed CO2 conversion rate greater than 95%, and a methanol selectivity of nearly 95% in the product.

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

[0110] Reactors R1 and R2 are filled with Co / Na-K / activated carbon bifunctional materials with Co impregnated with activated carbon-loaded KOH and NaOH as adsorption carriers. 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 the flue gas after desulfurization and denitrification from a coal-fired power plant, with a temperature of 40-60°C and a carbon dioxide content of 3-5 vol%. The flue gas volume space velocity entering the system is controlled to be maintained at 7000 h -1 , hydrogen volume space velocity at 8000h -1 ; The adsorption temperature is 80-100°C, preferably 90°C; The conversion temperature is 140-160°C, preferably 150°C; The temperature of the reactors R1 and R2 is controlled to be the same as the adsorption reaction temperature. First, adjust the flow control valve V2 to introduce hydrogen, start the plasma generating unit, adjust the frequency of 3200Hz and the discharge power of 1000W, and induce activation of the dual-functional materials in R1 and R2 for 3-4 hours; After the induced activation, turn off the plasma generating unit, close the flow control valve V4, and the flue gas is transported into the system through the program flow control valve V1, and enters the dust removal and purification device S1 for pretreatment, and the flue gas temperature is controlled to the conversion reaction temperature by the built-in temperature control module; The pretreated 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, and the hydrogen is transported into the system through the program flow control valve V2. After passing through the preheater H1, it reaches the adsorption reaction and conversion reaction temperature and enters the plasma fluidized conversion reactor R1; at the same time, the plasma generating unit is started to generate plasma in the reactor, and the frequency is adjusted to 1500Hz and the discharge power is 500W to carry out in-situ catalytic adsorption of carbon dioxide conversion. The gas-solid cyclone separators C1 and C2 are respectively used to separate the dual-functional material particles from the product gas and the decarbonized flue gas, so that the dual-functional material particles circulate between the adsorption reactor R2 and the conversion reactor R1. The separated decarbonized flue gas flowing out of the adsorption reactor R2 is directly discharged. The separated crude methanol flowing out of the conversion reactor R1 enters the condensation device D1 to remove the condensed water, and then enters the separation device P1 to purify the excess hydrogen using the pressure swing adsorption device, and the separated unreacted raw gas hydrogen enters the raw gas pipeline for recycling through the program flow control valve V3. In summary, the system can achieve a flue gas carbon dioxide capture rate greater than 95%, an adsorbed CO2 conversion rate greater than 97%, and a selectivity of olefins in the product close to 92%.

[0111] Some parameters of the above Example 4 are summarized in the following Table 2 for easy reading and analysis.

[0112] Table 2: Some 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 based on 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 performed using the multi-stage plasma fixed bed system of example 3. The plasma reactor of this comparative example was filled with only hydrotalcite adsorbent, not bifunctional material, and the adsorbent was not activated by plasma induction; the specific low-temperature plasma-promoted carbon capture and in-situ conversion process was as follows:

[0117] Reactors R1 and R2 are filled with hydrotalcite (LDH) adsorbent. The adsorbent is not activated by plasma induction, and the CO2 adsorption capacity is 1 mol / kg; the raw flue gas is the flue gas after desulfurization and denitrification from 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 is controlled to be maintained at 2000 h -1 , the hydrogen volume space velocity is 1000h -1; The adsorption and conversion temperature is 70-90°C, preferably 80°C. The flue gas is transported into the system through the flow control valve V1, and the air or industrial flue gas enters the dust removal and purification device S1 for pretreatment. The flue gas temperature is controlled to be the same as the adsorption and conversion temperature through the built-in temperature control module of the dust removal and purification device; the three-way flow control valves V2, V3, V4, and V5 are adjusted to allow the flue gas to enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the hydrotalcite; the three-way flow control valves V6, V7, V8, and V9 are adjusted to allow the decarbonized flue gas in R1 to be directly discharged after adsorption treatment through the three-way flow control valves V6 and V8 in sequence. When the CO2 adsorption of hydrotalcite in the reactor R1 reaches saturation, the three-way flow regulating valves V2, V3, V4, and V5 are adjusted to switch the flue gas input to R2 for CO2 adsorption, and at the same time, the plasma generating unit in R1 is started, and the frequency is adjusted to 50Hz and the discharge power is 100W; hydrogen is transported into the system through the flow regulating valve V10, and is preheated to the adsorption and conversion temperature by the preheater H1. The three-way flow regulating valves V2, V3, V4, and V5 are adjusted to allow hydrogen to enter the reactor R1, and the adsorbed CO2 is converted. The main conversion products detected 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 is recycled through the flow regulating valve V11. Similarly, when the CO2 adsorbed by the hydrotalcite adsorbent in R2 reaches saturation, the corresponding three-way flow control valve is adjusted to discharge the decarbonized flue gas in R2, and the plasma generating unit in R2 is started to introduce hydrogen into R2, and the CO generated 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 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 Example 1, and the multi-stage plasma fixed bed system of Example 3 was used for CO2 capture and conversion. The plasma reactor of this comparative example was filled with only NiCo bimetallic catalyst, not bifunctional material, and the catalyst was not activated by plasma induction; the specific low-temperature plasma-promoted carbon capture and in-situ conversion process was as follows:

[0120] Reactors R1 and R2 are both filled with NiCo bimetallic catalysts. Since there are very few alkaline adsorption sites on the surface of NiCo bimetallic catalysts, the CO2 adsorption capacity of NiCo bimetallic catalysts is only 0.1 mol / kg without plasma-induced activation. Even after plasma-induced activation, the CO2 adsorption capacity is only slightly increased to about 0.15 mol / kg. It can be seen that metal catalysts without the synergy of adsorption components do not have excellent CO2 adsorption performance. The raw flue gas is the flue gas after desulfurization and denitrification from 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 introduced into the system is controlled to be maintained at 2000h -1 , the hydrogen volume space velocity is 1000h -1 ; The adsorption and conversion temperature is 70-90°C, preferably 80°C. The flue gas is transported into the system through the flow control valve V1, and the air or industrial flue gas enters the dust removal and purification device S1 for pretreatment. The flue gas temperature is controlled to be the same as the adsorption and conversion temperature through the built-in temperature control module of the dust removal and purification device; the three-way flow control valves V2, V3, V4, and V5 are adjusted to allow the flue gas to enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the NiCo bimetallic catalyst; the three-way flow control valves V6, V7, V8, and V9 are adjusted to allow the decarbonized flue gas in R1 to be directly discharged after adsorption treatment through the three-way flow control valves V6 and V8 in sequence. The CO2 adsorption of the NiCo bimetallic catalyst in the reactor R1 quickly reaches 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 generating unit in R1 is started, and the frequency is adjusted to 50Hz and the discharge power is 100W; hydrogen is transported into the system through the flow control valve V10, and is 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 the reactor R1, and the adsorbed CO2 is converted in situ. The main conversion products detected are CH3OH, CH4, CO and CO2; the crude methanol product enters the condensing device D1 and the separation device P1 (gas-liquid separation device) in turn, and the unreacted hydrogen is reused through the flow control valve V11. Similarly, when the CO2 adsorbed by the NiCo bimetallic catalyst in R2 reaches saturation, the corresponding three-way flow control valve is adjusted to discharge the decarbonized flue gas in R2, and the plasma generation 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 about 20%, an adsorbed CO2 conversion rate of about 60%, and a methanol selectivity of only about 50%.

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

[0122] The method in reference example 1 was used to prepare hydrotalcite (LDH) adsorbent and K-containing NiCo bimetallic catalyst, respectively, and the multi-stage plasma fixed bed system of example 3 was used for CO2 capture and in-situ conversion. The plasma reactor of this comparative example was filled with only mixed particles of hydrotalcite adsorbent and K-containing NiCo bimetallic catalyst, rather than bifunctional materials, and the catalyst was not activated by plasma induction; the specific low-temperature plasma-promoted carbon capture and in-situ conversion process was as follows:

[0123] Reactors R1 and R2 are filled with K / NiCo-LDHs particles (NiCo bimetallic: LDH: K = 48.85%: 48.85%: 2.30%), which are simply physically and uniformly mixed with hydrotalcite adsorbent and K-containing NiCo bimetallic catalyst in a mass ratio of 1:1. The CO2 adsorption capacity of NiCo-LDHs particles without plasma-induced activation is 0.5 mol / 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°C and a carbon dioxide content of 7-15 vol%; the flue gas volume space velocity entering the system is controlled to be maintained at 2000h -1 , the hydrogen volume space velocity is 1000h -1; The adsorption and conversion temperature is preferably 80°C. The flue gas is transported into the system through the flow control valve V1, and the air or industrial flue gas enters the dust removal and purification device S1 for pretreatment. The flue gas temperature is controlled to be the same as the adsorption and conversion temperature through the built-in temperature control module of the dust removal and purification device; the three-way flow control valves V2, V3, V4, and V5 are adjusted to allow the flue gas to enter the reactor R1, and the carbon dioxide in the flue gas is adsorbed by the NiCo-LDHs particles; the three-way flow control valves V6, V7, V8, and V9 are adjusted to allow the decarbonized flue gas in R1 to be directly discharged after adsorption treatment through the three-way flow control valves V6 and V8 in sequence. When the adsorption of NiCo-LDHs particles in reactor R1 reaches saturation, adjust the three-way flow control valves V2, V3, V4, and V5, switch to flue gas input to R2 for CO2 adsorption, and start the plasma generating unit in R1 at the same time, adjust the frequency to 50Hz, and the discharge power to 100W; hydrogen is transported into the system through the flow control valve V10, preheated to the adsorption and conversion temperature by the preheater H1, and the three-way flow control valves V2, V3, V4, and V5 are adjusted to allow hydrogen to enter the reactor R1, and the adsorbed CO2 is converted. The main conversion products detected are CH3OH, CH4, CO and CO2; the crude methanol product enters the condensing device D1 and the separation device P1 (gas-liquid separation device) in turn, and the unreacted hydrogen is recycled through the flow control valve V11. Similarly, when the CO2 adsorbed by the NiCo-LDHs particles in R2 reaches saturation, the corresponding three-way flow control valve is adjusted to discharge the decarbonized flue gas in R2, and the plasma generation 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 system for low-temperature plasma-coupled dual-functional materials to synergize carbon dioxide capture and in-situ conversion, comprising a pretreatment unit (1), a plasma generation unit (2), a carbon capture-conversion integrated unit (3) and a separation-purification unit (4), characterized in that: The carbon dioxide is carbon dioxide in air or industrial flue gas; the carbon capture-conversion integrated unit (3) is filled with a bifunctional material, wherein the bifunctional material comprises an adsorption component and a catalytic component; the reaction temperature of the carbon capture-conversion integrated unit (3) is 0 to 210° C., and the reaction is an adsorption reaction or a conversion reaction.

2. The system of low-temperature plasma coupled dual-functional materials for coordinated carbon dioxide capture and in-situ conversion as claimed in claim 1, characterized in that: The adsorption component is selected from a combination of one or more of hydrotalcite, zeolite, activated carbon, modified ion resin, calcium oxide, magnesium oxide, solid-loaded amino, sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide; the catalytic component is selected from a combination of one or more of metals or metal oxides of iron, nickel, cobalt, copper, ruthenium, platinum, palladium, rhodium, and zinc; the mass percentage of the adsorption component in the dual-functional material is 0.1 to 99 wt%, and the mass percentage of the catalytic component in the dual-functional material is 0.1 to 60 wt%.

3. The system of low-temperature plasma coupled dual-functional materials for coordinated carbon dioxide capture and in-situ conversion as claimed in claim 2, characterized in that: The bifunctional material further comprises a catalytic promoter component, which is selected from a combination of one or more of cerium, potassium, sodium, phosphorus and nitrogen; the mass percentage of the catalytic promoter component in the bifunctional material is 0 to 20 wt%.

4. The system for low-temperature plasma coupled dual-functional materials to coordinate carbon dioxide capture and in-situ conversion according to any one of claims 1 to 3, characterized in that: The pretreatment unit (1) comprises 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) comprises a high-frequency AC power supply, a voltage controller, an oscilloscope and a high-voltage electrode, wherein the high-voltage electrode is embedded in the plasma reactor of the carbon capture-conversion integrated unit (3); The carbon capture-conversion integrated unit (3) comprises a plasma reactor, a program flow control valve and a temperature control module; The plasma reactor is a multi-stage parallel plasma fixed bed reactor or a circulating plasma fluidized bed reactor; the plasma reactor is filled with a dual-function material; The separation-purification unit (4) 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 (4) is connected to the carbon capture-conversion integrated unit (3).

5. A method for capturing and converting carbon dioxide in situ using the system according to any one of claims 1 to 4, characterized in that: In the method, the carbon capture-conversion integrated unit (3) captures and converts carbon dioxide in the air or industrial flue gas under the action of plasma and reducing gas, and specifically comprises the following steps: S1: Plasma-induced activation of the bifunctional material: a reducing gas is introduced into a plasma reactor filled with the bifunctional material in the carbon capture-conversion integrated unit (3), and under the action of plasma, active hydroxyl groups are induced to be 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 be reduced under low temperature conditions; S2: Air / flue gas pretreatment: The air or industrial flue gas input into the system first passes through the dust removal and purification device in the pretreatment unit (1), and removes fine dust particles in the air or industrial flue gas by using 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 capture: The pre-treated air or industrial flue gas is introduced into the plasma reactor, and after adsorption treatment by the dual-functional material, low-temperature capture of carbon dioxide is achieved; the decarbonized air or industrial flue gas after adsorption treatment is directly discharged; S4: In-situ conversion of adsorbed carbon dioxide: The raw gas is introduced into the plasma reactor by controlling the valve, and the carbon dioxide is converted in-situ under the catalysis of the bifunctional material and the action of plasma to generate product gas containing the target product; S5: Product gas separation and purification: The product gas enters the condensing device and the separation device in the separation-purification unit (4) in sequence, collects the separated target product, and controls the valve to allow the separated incompletely reacted raw gas to re-enter the raw gas pipeline for recycling.

6. The method according to claim 5, characterized in that The raw material gas is selected from one or more combinations of hydrogen, water vapor, ammonia, carbon monoxide, methane and ethane.

7. The method according to claim 5, characterized in that 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 entering the plasma reactor; the time for inducing activation of the dual-functional material is 1 minute to 10 hours.

8. The method according to claim 5, characterized in that In step S2, the air or industrial flue gas is introduced into the plasma reactor at a volume space velocity of 10 to 10,000 h -1 .

9. The method according to claim 5, characterized in that In step S3, the volume space velocity of the raw gas entering the plasma reactor is 100 to 10000 h -1 ; The target product is selected from carbon monoxide, synthesis gas, methane, methanol or olefins.

10. The method according to any one of claims 5 to 9, wherein the plasma reactor is a multistage parallel plasma fixed bed reactor, wherein the multistage parallel plasma fixed bed reactor is a dual parallel plasma fixed bed reactor; when the carbon dioxide adsorption amount of the dual-functional material in one of the reactors reaches saturation, the plasma generating unit (2) corresponding to the reactor is started, and the raw gas is introduced into the reactor through a control valve for in-situ conversion, and at the same time, air or industrial flue gas is introduced into the other reactor for carbon dioxide adsorption.

11. The method according to any one of claims 5 to 9, wherein the plasma reactor is a circulating plasma fluidized bed reactor, comprising an adsorption reactor and a conversion reactor; when the carbon dioxide adsorption amount of the dual-functional material in the adsorption reactor reaches saturation, a cyclone separator is used to separate the dual-functional materials in the adsorption reactor and the conversion reactor, and then the dual-functional materials are respectively introduced into the two reactors through pipelines to achieve replacement of the dual-functional materials in the two reactors.

12. Use of the system according to any one of claims 1 to 4 in carbon dioxide capture and in-situ conversion.

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