A molten carbonate fuel cell pyrolysis and gasification biomass reaction device and method for fluidized bed electrodes

Abstract

This invention belongs to the field of fuel cells and biomass utilization, and relates to a pyrolysis and gasification biomass reaction device and method for a molten carbonate fuel cell with a fluidized bed electrode. This invention enhances the mass transfer process between biomass and molten electrolyte within the fluidized bed electrode by forming a bubbling or diffused fluidization within the fluidized bed anode chamber, thereby improving battery performance. The gasification and oxidation reactions of biomass provide fuel for the fuel cell. A portion of the carbon dioxide generated by the electrochemical reaction is supplied to the cathode reaction, while the remainder can be directly stored. The molten carbonate reacts with the biomass in a gasification and oxidation reaction, increasing the porosity of the biochar; it also dissolves the alkali metal ash in the biomass, further improving the performance of the biochar, while simultaneously generating electricity and heat.

Description

Technical Field

[0001] This invention belongs to the field of fuel cells and biomass utilization, and particularly relates to a pyrolysis gasification biomass reaction device and method for a fluidized bed electrode molten carbonate fuel cell. Background Technology

[0002] Biomass, as the only renewable carbon source, can alleviate the energy crisis and effectively reduce carbon emissions during energy use through efficient utilization. Biochar, prepared through pyrolysis and gasification, can be directly applied in adsorption, electrochemistry, metallurgy, and fuels. Furthermore, biochar can improve soil quality, achieving negative carbon utilization of biomass. However, biochar obtained through direct pyrolysis has low porosity, and its high ash content reduces its quality, making it difficult to meet industrial application standards. Therefore, subsequent activation and pore-forming processes, or acid washing and deashing, are required, increasing the cost and energy consumption of the biochar.

[0003] Molten carbonate fuel cells are energy conversion devices that use molten carbonate as the electrolyte material. They can directly convert the chemical energy of fuel into electrical energy and also provide high-quality heat due to their high reaction temperature. However, the mass transfer process of fuel in the liquid electrolyte is relatively slow, which limits the electrochemical reaction rate and performance of the cell.

[0004] Fluidization technology has been widely used in many fields such as energy, environment, and chemical industry. According to the state of matter, fluidization technology can be divided into gas-solid phase, solid-liquid phase and gas-liquid-solid three-phase fluidization. It has the advantages of high heat and mass transfer rate, strong reaction capacity, large unit throughput and easy scale-up. It can greatly reduce the operating risks of the device caused by reaction and temperature unevenness.

[0005] Fluidized bed electrodes are currently used in the fuel cell field. Patent CN102324539A provides a fluidized bed electrode direct carbon fuel cell device, which includes a fluidized bed, two or more tubular single cells, a current collector, composite carbon fuel, a gas circulation device, a screw feeder, and a fuel tank. Addressing the low mass transfer rate problem in gas-solid phase reaction systems, this invention, based on solid oxide direct carbon fuel cells, adds a conductive catalyst to the solid carbon fuel, expanding the direct electrochemical reaction interface of carbon from two-dimensional to three-dimensional and promoting the gasification reaction of carbon, thereby improving battery performance.

[0006] Regarding molten carbonate fuel cells, patent CN113169367B proposes a molten carbonate direct carbon fuel cell system and method. The system uses carbon particles as fuel, and the fuel supply device is used to allow a fuel slurry containing carbon particles and a carbon carrier fluid to flow in parallel to the anode of the fuel cell. The carbon is oxidized at the anode of the fuel cell to produce carbon dioxide, and oxygen and carbon dioxide react at the cathode of the fuel cell to produce carbonate ions.

[0007] This patent is the first to propose a fluidized bed electrode molten carbonate fuel cell reactor that directly pyrolyzes and gasifies biomass, co-producing electricity, heat, and high-quality biochar. Fluidization enhances the mass transfer process between biomass and the molten electrolyte within the electrode, improving battery performance. Using biomass directly as a raw material, the pyrolysis gas and gasification gas from the biomass provide gaseous fuel for the fuel cell, while the biochar provides solid fuel. A portion of the carbon dioxide generated by the electrochemical reaction supplies the cathode reaction, and the remainder can be directly stored. The molten carbonate reacts with the biomass through gasification and oxidation, increasing the porosity of the biochar; furthermore, the molten salt can dissolve the alkali metal ash in the biomass, further improving the performance of the biochar. Simultaneously producing electricity and heat, this technology has broad application prospects. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a pyrolysis and gasification biomass reaction device and method for molten carbonate fuel cells with fluidized bed electrodes, which solves the problems of slow mass transfer rate and poor electrochemical performance within the electrodes of molten carbonate fuel cells, while also addressing the challenge of ash content in biomass affecting biochar quality.

[0009] The technical solution provided by this invention is as follows:

[0010] This invention provides a molten carbonate fuel cell pyrolysis gasification biomass reaction device with a fluidized bed electrode, comprising a first chamber and a second chamber separated by a diaphragm. The first chamber includes a fluidized bed anode chamber and a fixed anode, and the second chamber includes a cathode chamber and a cathode. The fixed anode and cathode are located in the fluidized bed anode chamber and cathode chamber, respectively. The fluidized bed anode chamber is provided with an external pipeline, on which a circulation pump and a biomass feeding device and a carbon recovery device are respectively located at both ends of the circulation pump. An anode inlet and an anode outlet are respectively provided at the bottom and top of the fluidized bed anode chamber. The external pipeline, biomass feeding device, and carbon recovery device constitute a liquid-solid circulation device. A cathode inlet and a cathode outlet are respectively provided at the bottom and top of the cathode chamber. An air distribution plate is installed at the inlet. The fluidized bed anode chamber is filled with an active catalyst and an electrolyte material. The output end of the fuel cell is connected to an external load system.

[0011] Furthermore, it also includes a heat exchanger, through which the gaseous products are cooled, and the released heat heats the water to produce steam.

[0012] Furthermore, the diaphragm is made of LiAlO2 material, the cathode is made of LiCoO2 material, and the fixed anode is made of metallic nickel material.

[0013] This invention also provides a method for combined heat and power generation in a molten carbonate fuel cell pyrolysis gasification biomass reactor with a fluidized bed electrode as described above, characterized by comprising the following steps:

[0014] First, electrolyte material is placed in the fluidized bed anode chamber and heated to 400-750 ℃ ​​to form molten electrolyte. Then, an appropriate amount of active catalyst is dispersed into the molten electrolyte.

[0015] The circulating pump and biomass feeding device are started to add the crushed biomass raw material into the fluidized bed anode chamber. Anode fluidizing air is selectively introduced at the bottom of the fluidized bed anode chamber, and a mixture of air and carbon dioxide is introduced at the bottom of the cathode chamber.

[0016] In the fluidized bed anode chamber, biomass feedstock undergoes pyrolysis and gasification in molten electrolyte to generate pyrolysis gas and biochar. Alkali metal salts in the biomass or biochar are dissolved by the molten electrolyte. The biochar and pyrolysis gas react with carbonate ions (as oxidants) to oxidize them into carbon dioxide and water, releasing electrons. The carbon dioxide and water generated at the anode are condensed after heat exchange to obtain high-concentration carbon dioxide, which is used as anode fluidizing air or cathode makeup gas. Some biochar follows the molten electrolyte into a carbon recovery device for separation. The separated molten salt is then mixed with new biomass feedstock and returned to the fluidized bed anode chamber for further reaction. The fluidization number of the anode fluidizing air is controlled by the anode inlet to form a gas-liquid-solid bubbling fluidization or by controlling the circulation pump flow rate to form a liquid-solid dispersed fluidization. This bubbling or dispersed fluidization promotes the interaction and mass transfer between the active catalyst particles, biomass particles, and molten electrolyte, increasing the oxygen partial pressure on the surface of the biomass particles, enhancing the gasification reaction, and promoting the formation of biochar channels.

[0017] Inside the cathode chamber, electrons from the anode are received via an external circuit, triggering an electrochemical reaction that generates carbonate ions to sustain the fuel cell's operation.

[0018] Furthermore, the biomass has a moisture content of 0-20%; when in a bubbling fluidized state, the diameter of the crushed biomass raw material is between 300-5000 μm on a wide screen; when in a bulk fluidized state, the diameter of the crushed biomass raw material is between 200-500 μm on a narrow screen.

[0019] Furthermore, when in bubbling fluidized state, the gas fluidization number is controlled within the range of 3-15; when in diffuse fluidized state, the circulating pump flow rate fluidization number is controlled within the range of 3-10.

[0020] Furthermore, the anode fluidizing air is water, carbon dioxide, or a mixture of water and carbon dioxide.

[0021] Furthermore, the molten electrolyte is a carbonate mixture of 60 wt% Li2CO3 and 40 wt% K2CO3.

[0022] Furthermore, the active catalyst is selected from any one or more of single metals, polymetals, or perovskite materials.

[0023] Furthermore, the active catalyst is selected from nickel particles or La. 0.6 Sr 0.4 Fe 0.9 Ni 0.1 O 3-δ Any one or more of the following.

[0024] Beneficial effects

[0025] The main objective of this invention is to achieve combined heat and power generation (CHP) of biomass pyrolysis and gasification using a molten carbonate fuel cell reactor with a fluidized bed electrode. Biomass is heated within the fluidized bed anode and undergoes pyrolysis and gasification reactions with carbon dioxide or water vapor. The resulting pyrolysis gas and some biochar react electrochemically with carbonate ions at the anode to generate water vapor and carbon dioxide, outputting electricity and heat. The fluidized bed electrode enhances the mass transfer process between biomass particles, molten carbonate, and bubbles, improving the reaction rate of biomass and the performance of the battery. This device utilizes fluidized molten carbonate for efficient pyrolysis and gasification of biomass, generating electricity while simultaneously producing biochar. The molten carbonate reacts with the biomass through gasification and oxidation, increasing the porosity of the biochar. Furthermore, under high-temperature conditions, the molten carbonate can directly dissolve alkali metal salts in the biomass, improving the quality of the biochar.

[0026] This invention improves battery performance by creating a bubbling or diffused fluidized bed electrode within the anode chamber, thereby enhancing the mass transfer process between biomass and molten electrolyte. The gasification and oxidation of biomass provide fuel for the fuel cell, while a portion of the high-concentration carbon dioxide generated by the electrochemical reaction is supplied to the cathode reaction, and the remainder can be directly stored. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a molten carbonate fuel cell pyrolysis gasification biomass reaction device with fluidized bed electrodes.

[0028] Explanation of reference numerals in the attached diagram: 1. Fluidized bed anode chamber; 2. Fixed anode; 3. Diaphragm; 4. Cathode; 5. Cathode chamber; 6. External load; 7. Circulating pump; 8. Biomass feeding device; 9. Carbon recovery device. Detailed Implementation

[0029] The specific embodiments of the present invention will be further explained below.

[0030] Example 1

[0031] like Figure 1 As shown, this embodiment of the invention provides a molten carbonate fuel cell pyrolysis gasification biomass reaction device with a fluidized bed electrode, including a first chamber and a second chamber, which are separated by a diaphragm 3. The first chamber includes a fluidized bed anode chamber 1 and a fixed anode 2, and the second chamber includes a cathode chamber 5 and a cathode 4. The fixed anode and cathode are located in the fluidized bed anode chamber 1 and cathode chamber 5, respectively. The fluidized bed anode chamber 1 is provided with an external pipe, and a circulation pump 7 and a biomass feeding device 8 and a carbon recovery device 9 are respectively located at both ends of the circulation pump 7. An anode inlet and an anode outlet are respectively provided at the bottom and top of the fluidized bed anode chamber 1. The fluidized bed anode pipe, the biomass feeding device 8, and the carbon recovery device 9 constitute a liquid-solid circulation device. A cathode inlet and a cathode outlet are respectively provided at the bottom and bottom of the cathode chamber 5. An air distribution plate is installed at the anode inlet. The fluidized bed anode chamber 1 is filled with an active catalyst and an electrolyte material. The output end of the fuel cell is connected to an external load system.

[0032] In this embodiment, a heat exchanger is also included. The gasification products are cooled by the heat exchanger, and the heat released by the temperature reduction heats the water to generate water vapor.

[0033] In this embodiment, the diaphragm is made of LiAlO2, the cathode is made of LiCoO2, and the fixed anode is made of nickel. The electrolyte is a mixture of 60 wt% Li2CO3 and 40 wt% K2CO3, and the biomass is crushed pine wood pellets. The active catalyst is selected from any one or more of monometallic, polymetallic, or perovskite materials.

[0034] Example 2

[0035] This invention provides a method for combined heat and power generation in a molten carbonate fuel cell pyrolysis gasification biomass reactor using the fluidized bed electrode described in Example 1, comprising the following steps:

[0036] First, electrolyte material is added to the battery and heated to 650℃ to form a molten electrolyte. Then, an appropriate amount of 100-200μm Ni active catalyst is dispersed into the molten electrolyte at the anode. The selection of the active catalyst mainly considers two aspects: fluidization and separation. If the particles are too large, they are not easy to fluidize and will be separated out along with the biochar, resulting in catalyst loss.

[0037] Considering the fluidizing air disturbance within the bubbling bed, wide-screen biomass is used for fluidization to reduce the cost of biomass crushing and processing. The circulating pump and biomass feeding device are started to add the crushed biomass raw material (wide screen 300-5000μm, moisture content 10%) into the fluidized bed anode chamber. At the same time, anode fluidizing air (carbon dioxide) is introduced at the bottom of the fluidized bed anode chamber, and the anode fluidization number is controlled to be 3-15, specifically 5, to form a bubbling fluidized state. A mixture of air and carbon dioxide is introduced at the bottom of the cathode chamber.

[0038] In the fluidized bed anode chamber, biomass feedstock undergoes pyrolysis in molten electrolyte, generating pyrolysis gas and biochar. The biochar further undergoes gasification with the anode fluidizing air, increasing its porosity. Alkali metal salts in the biomass or biochar dissolve and precipitate in the molten electrolyte, further improving the biochar's quality. The biochar and pyrolysis gas react electrochemically with carbonate ions in the anode, oxidizing them to carbon dioxide and water and releasing electrons. The carbon dioxide and water generated at the anode are condensed after heat exchange to obtain high-concentration carbon dioxide, which serves as anode fluidizing air or cathode makeup gas. Unreacted biochar follows the molten electrolyte into a carbon recovery unit for separation. The separated molten salt is then mixed with new biomass feedstock and returned to the fluidized bed anode chamber for further reaction. The movement of biomass particles in the molten salt accelerates the ash dissolution process, allowing alkali metal salts (potassium carbonate) in the biomass to dissolve directly in the electrolyte solution, replenishing the electrolyte solution and improving the biochar's quality. After the active catalyst nickel particles come into contact with the stationary anode, new electrochemical reaction active interfaces are continuously generated, reducing the activation polarization of the battery. The increased contact probability between biochar particles and the gaseous gases produced in the reaction with carbonate ions allows for the timely removal of water and carbon dioxide generated by the electrochemical reaction, reducing concentration polarization losses and comprehensively improving battery performance. The bubbling fluidization formed by carbon dioxide as fluidizing air enhances the interaction and mass transfer processes between the fluidizing air, active catalyst particles, biomass particles, and molten electrolyte. This increases the oxygen partial pressure on the surface of the biomass particles, inhibits carbon deposition on the active catalyst surface, strengthens the biomass gasification reaction, and promotes the formation of biochar channels. Compared with the fluidization number of 1, the biochar mass yield decreased from 28.5% to 22.3%. The BET (Brunauer–Emmett–Teller) method was used to analyze the surface area of ​​the biochar, and the specific surface area increased from 345 m² / s. 2 / g increased to 420 m2 / g. The biochar was analyzed using the national standard GB / T 28731-2012, "Analytical Methods for Solid Biomass Fuels in Industry." The ash content of the biochar prepared by this method was 0.18%, lower than the ash content of pine char prepared by fixed-bed pyrolysis (2.2%). The carbon dioxide content of the anode tail gas after cooling was greater than 90%, allowing for direct carbon capture and utilization.

[0039] Inside the cathode chamber, electrons from the anode are received via an external circuit, triggering an electrochemical reaction that generates carbonate ions to sustain the fuel cell's operation.

[0040] During the stable operation phase of the device, biomass is continuously fed in from the top and generates biochar through pyrolysis and gasification. The biochar, along with the electrolyte molten salt, enters the filtration device for separation. The separated molten salt is then mixed with new biomass feedstock and returned to the fluidized bed anode chamber for further reaction. The pyrolysis gas produced by the biomass and some of the biochar directly undergo electrochemical reactions to generate carbon dioxide, water vapor, and electricity.

[0041] Example 3

[0042] This invention provides a method for combined heat and power generation in a molten carbonate fuel cell pyrolysis gasification biomass reactor using the fluidized bed electrode described in Example 1, comprising the following steps:

[0043] First, add electrolyte material to the battery and heat to 650 °C to form a molten electrolyte. Then, add an appropriate amount of 100-200 μm La. 0.6 Sr 0.4 Fe 0.9 Ni 0.1 O 3-δ The perovskite material active catalyst is dispersed and added to the molten electrolyte at the anode.

[0044] The circulating pump and biomass feeding device are started to add crushed biomass raw material (narrowly screened 200-500μm (the size of the biomass particles is conducive to the dispersion of solids in molten salt and is more conducive to the formation of bulk fluidization) with a moisture content of 15%) into the fluidized bed anode chamber. The fluidization number of the circulating pump is controlled to be 3-10. Specifically, the fluidization number of the circulating pump is 3 to form bulk fluidization. A mixture of air and carbon dioxide is introduced into the bottom of the cathode chamber.

[0045] In the fluidized bed anode chamber, biomass feedstock undergoes pyrolysis in molten electrolyte, producing pyrolysis gas and biochar. Alkali metal salts in the biomass or biochar dissolve and precipitate in the molten electrolyte, further improving the quality of the biochar. The biochar and pyrolysis gas react electrochemically with carbonate ions in the anode, oxidizing them into carbon dioxide and water and releasing electrons. The carbon dioxide and water generated at the anode are condensed after heat exchange to obtain high-concentration carbon dioxide, which serves as cathode makeup gas. Unreacted biochar follows the molten electrolyte into a carbon recovery unit for separation. The separated molten salt is then mixed with new biomass feedstock and returned to the fluidized bed anode chamber for further reaction. The movement of biomass particles in the molten salt accelerates the ash dissolution process, allowing alkali metal salts (potassium carbonate) in the biomass to dissolve directly in the electrolyte solution, replenishing the electrolyte solution and improving the quality of the biochar. 0.6 Sr 0.4 Fe 0.9 Ni 0.1 O 3-δ After contacting the perovskite active catalyst with the stationary anode, new electrochemical reaction active interfaces are continuously generated, reducing the activation polarization of the battery. The increased contact probability between biochar particles and the gaseous gases produced in the reaction with carbonate ions, along with the timely removal of water and carbon dioxide generated in the electrochemical reaction, reduces concentration polarization losses and comprehensively improves battery performance. The dispersed fluidization formed by controlling the circulation pump flow rate enhances the interaction and mass transfer processes between the active catalyst particles, biomass particles, and molten electrolyte, promoting biomass gasification and electrochemical reactions. Using perovskite active catalysts helps reduce carbon deposition on their surfaces. Compared to the fluidization number of 1, the biochar mass yield decreased from 28.8% to 24.5%. The BET (Brunauer–Emmett–Teller) method was used to analyze the biochar surface area, and the specific surface area increased from 314 m² / s. 2 / g increased to 392 m 2 / g. The biochar was analyzed using the national standard GB / T 28731-2012, "Analytical Methods for Solid Biomass Fuels in Industry." The ash content of the biochar prepared by this method was 0.32%, lower than the ash content of pine char prepared by fixed-bed pyrolysis (2.2%). Electrochemical impedance spectroscopy analysis and fitting revealed a decrease of approximately 30% in the concentration polarization of the fuel cell anode, indicating a significant improvement in the anode mass transfer process. After cooling, the carbon dioxide content of the anode tail gas was greater than 80%, allowing for direct carbon capture and utilization.

[0046] Inside the cathode chamber, electrons from the anode are received via an external circuit, triggering an electrochemical reaction that generates carbonate ions to sustain the fuel cell's operation.

[0047] During the stable operation phase of the device, biomass is continuously fed in from the top and generates biochar through pyrolysis. The biochar, along with the molten electrolyte salt, enters the filtration device for separation. The separated molten salt is then mixed with new biomass feedstock and returned to the fluidized bed anode chamber for further reaction. The pyrolysis gas produced by the biomass and some of the biochar directly undergo electrochemical reactions to generate carbon dioxide, water vapor, and electricity.

[0048] The above detailed embodiments describe the implementation of the present invention. It should be noted that the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A fluidized bed electrode pyrolysis gasification biomass reactor for a molten carbonate fuel cell, characterized in that, The fuel cell includes a first chamber and a second chamber separated by a diaphragm. The first chamber includes a fluidized bed anode chamber and a fixed anode, and the second chamber includes a cathode chamber and a cathode. The fixed anode and cathode are located in the fluidized bed anode chamber and cathode chamber, respectively. The fluidized bed anode chamber is equipped with an external pipeline, on which a circulation pump and a biomass feeding device and a carbon recovery device are located at opposite ends of the circulation pump. The bottom and top of the fluidized bed anode chamber are respectively provided with an anode inlet and an anode outlet. The external pipeline, biomass feeding device, and carbon recovery device constitute a liquid-solid circulation device. The bottom and top of the cathode chamber are respectively provided with a cathode inlet and a cathode outlet. An air distribution plate is installed at the inlet. The fluidized bed anode chamber is filled with an active catalyst and electrolyte material. The output end of the fuel cell is connected to an external load system.

2. The fluidized bed electrode molten carbonate fuel cell pyrolysis gasification biomass reaction apparatus according to claim 1, characterized in that, It also includes a heat exchanger, through which the gaseous products are cooled, and the released heat heats the water to produce steam.

3. The fluidized bed electrode molten carbonate fuel cell pyrolysis gasification biomass reaction apparatus according to claim 1, characterized in that, The diaphragm is made of LiAlO2 material, the cathode is made of LiCoO2 material, and the fixed anode is made of metallic nickel material.

4. The method for combined heat and production of biomass in a molten carbonate fuel cell pyrolysis gasification biomass reactor with a fluidized bed electrode as described in any one of claims 1-3, characterized in that, Includes the following steps: First, electrolyte material is placed in the fluidized bed anode chamber and heated to 400-750 ℃ ​​to form molten electrolyte. Then, an appropriate amount of active catalyst is dispersed into the molten electrolyte. The circulating pump and biomass feeding device are started to add the crushed biomass raw material into the fluidized bed anode chamber. Anode fluidizing air is selectively introduced at the bottom of the fluidized bed anode chamber, and a mixture of air and carbon dioxide is introduced at the bottom of the cathode chamber. In the fluidized bed anode chamber, biomass feedstock undergoes pyrolysis and gasification in molten electrolyte to generate pyrolysis gas and biochar. Alkali metal salts in the biomass or biochar are dissolved by the molten electrolyte. The biochar and pyrolysis gas react with carbonate ions (as oxidants) to oxidize them into carbon dioxide and water, releasing electrons. The carbon dioxide and water generated at the anode are condensed after heat exchange to obtain high-concentration carbon dioxide, which is used as anode fluidizing air or cathode makeup gas. Some biochar follows the molten electrolyte into a carbon recovery device for separation. The separated molten salt is then mixed with new biomass feedstock and returned to the fluidized bed anode chamber for further reaction. The fluidization number of the anode fluidizing air is controlled by the anode inlet to form a gas-liquid-solid bubbling fluidization or by controlling the circulation pump flow rate to form a liquid-solid dispersed fluidization. This bubbling or dispersed fluidization promotes the interaction and mass transfer between the active catalyst particles, biomass particles, and molten electrolyte, increasing the oxygen partial pressure on the surface of the biomass particles, enhancing the gasification reaction, and promoting the formation of biochar channels. Inside the cathode chamber, electrons from the anode are received via an external circuit, triggering an electrochemical reaction that generates carbonate ions to sustain the fuel cell's operation.

5. The method according to claim 4, characterized in that, The biomass has a moisture content of 0-20%; when in bubbling fluidized state, the diameter of the crushed biomass raw material is between 300-5000 μm on a wide screen; when in bulk fluidized state, the diameter of the crushed biomass raw material is between 200-500 μm on a narrow screen.

6. The method according to claim 4, characterized in that, When in bubbling fluidized state, the fluidization number is controlled within the range of 3-15; when in loose fluidized state, the fluidization number is controlled within the range of 3-10.

7. The method according to claim 4, characterized in that, The anode fluidizing air is water, carbon dioxide, or a mixture of water and carbon dioxide.

8. The method according to claim 4, characterized in that, The molten electrolyte is a carbonate mixture of 60 wt% Li2CO3 and 40 wt% K2CO3.

9. The method according to claim 4, characterized in that, The active catalyst is selected from any one or more of single metals, polymetals, or perovskite materials.

10. The method according to claim 9, characterized in that, The active catalyst is selected from nickel particles or La. 0.6 Sr 0.4 Fe 0.9 Ni 0.1 O 3-δ Any one or more of the following.

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