Power generation system for coupling methane cracking hydrogen production with solid oxide fuel cell

Abstract

The invention relates to a power generation system for coupling methane cracking hydrogen production with a solid oxide fuel cell, which is characterized by comprising a solid oxide fuel cell power generation module, a methane cracking hydrogen production module, an afterburning module and an air preheating module, methane gas passes through the methane cracking hydrogen production module to prepare hydrogen, the prepared hydrogen is respectively fed into the solid oxide fuel cell power generation module and the afterburning module to participate in reaction through a three-way valve, and the air preheating module is used for preheating air and then feeding the air into the solid oxide fuel cell power generation module to participate in reaction. And the afterburning module is used for feeding high-temperature gas generated after the reaction of hydrogen and air into the methane cracking hydrogen production module for providing heat for the methane cracking hydrogen production module. According to the invention, a methane direct cracking hydrogen production process is combined with a solid oxide fuel cell power generation system, so that the problems of tedious process flow, complex system, high carbon emission, large water consumption and the like of a methane hydrogen production coupling solid oxide fuel cell power generation system are solved.

Description

Technical Field

[0001] The present invention relates to a solid oxide fuel cell (SOFC) power generation system, and in particular to a power generation system that couples methane cracking to produce hydrogen with a solid oxide fuel cell. Background Art

[0002] Methane-to-hydrogen coupled with solid oxide fuel cell (SOFC) power generation systems has broad application prospects in distributed power generation systems and mobile power sources. Existing patents mostly propose using a methane steam reforming process to provide hydrogen. This process requires multiple steps, including the steam reforming reaction (CH4 + H2O → CO + 3H2), the water-gas shift reaction (CO + H2O → CO2 + H2), and the separation and purification of H2 and CO2. The methane steam reforming process suffers from cumbersome procedures, complex systems, high carbon emissions, and high water consumption. To address these issues, the present invention proposes a method for producing hydrogen through direct methane cracking. This method, which produces hydrogen in a single process, achieves zero carbon emissions from the methane cracking-to-hydrogen coupled SOFC power generation system, simplifies the hydrogen-carbon separation process, and reduces system energy consumption. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the present invention aims to provide a power generation system for methane cracking and hydrogen production coupled with solid oxide fuel cells. By combining the direct methane cracking and hydrogen production process with the solid oxide fuel cell power generation system, it is used to overcome the problems of the methane hydrogen production coupled with solid oxide fuel cell power generation system, such as cumbersome process flow, complex system, high carbon emissions, and high water consumption.

[0004] The present invention is achieved through the following technical solutions.

[0005] A power generation system for methane cracking hydrogen production coupled with a solid oxide fuel cell, characterized by comprising a solid oxide fuel cell power generation module, a methane cracking hydrogen production module, a supplemental combustion module, and an air preheating module; methane gas passes through the methane cracking hydrogen production module to produce hydrogen, and the produced hydrogen is respectively fed into the solid oxide fuel cell power generation module and the supplemental combustion module through a three-way valve to participate in the reaction; the air preheating module preheats the air and then feeds it into the solid oxide fuel cell power generation module to participate in the reaction; the supplemental combustion module feeds the high-temperature gas generated by the reaction of hydrogen and air into the methane cracking hydrogen production module to provide heat to the methane cracking hydrogen production module;

[0006] The solid oxide fuel cell power generation module includes an anode and a cathode, hydrogen and air are fed into the anode and the cathode respectively and electrochemical reactions occur to generate electricity;

[0007] The methane cracking hydrogen production module includes a methane cracking hydrogen production reactor, a cracking reaction catalyst, a methane cracking hydrogen production reactor sleeve, and a hydrogen-carbon separator. The methane cracking hydrogen production reactor sleeve is attached to the outer wall of the methane cracking hydrogen production reactor, and the cracking reaction catalyst is placed in the methane cracking hydrogen production reactor. Methane gas is fed into the methane cracking hydrogen production reactor from the bottom and reacts with the cracking reaction catalyst during the gradual floating process. The densities of methane, carbon, and hydrogen are all less than the density of the cracking reaction catalyst, so that the reaction products of the methane cracking hydrogen production module float to the top of the cracking reaction catalyst and are separated by the hydrogen-carbon separator. The separated hydrogen is respectively transported to the solid oxide fuel cell power generation module and the supplementary combustion module through a three-way valve.

[0008] Furthermore, methane gas forms methane bubbles in the cracking reaction catalyst. After the cracking reaction catalyst and methane bubbles are heated, the methane bubbles undergo a cracking reaction under the action of the high temperature environment and the catalyst: CH4→C+2H2. The carbon product is recovered, and the hydrogen is distributed according to demand through the three-way valve.

[0009] Furthermore, it also includes an exhaust gas combustion module, which includes an exhaust gas burner. The residual hydrogen at the anode outlet of the solid oxide fuel cell power generation module is mixed with the residual air at the cathode outlet and burned to produce high-temperature exhaust gas, and the high-temperature gas is sent to the supplementary combustion module.

[0010] Furthermore, the afterburner module includes an afterburner, the tail gas burner generates high-temperature tail gas which is sent into the afterburner, and the air compressor 2 compresses the air and sends it into the afterburner. The high-temperature tail gas generated by the tail gas burner, the air compressed by the air compressor 2, and the hydrogen generated by the methane cracking hydrogen production module burn and react in the afterburner to further increase the temperature of the high-temperature tail gas. The high-temperature gas generated by the afterburner combustion is sent into the casing of the methane cracking hydrogen production reactor to provide heat to the methane cracking hydrogen production reactor.

[0011] Furthermore, the air preheating module includes an air preheater. The air compressor compresses the air and sends it into the air preheater. The tail gas at the sleeve outlet of the methane cracking hydrogen production reactor is sent into the air preheater to preheat the compressed air. The tail gas after passing through the air preheater is discharged into the atmospheric environment.

[0012] Furthermore, the methane gas is compressed by a methane compressor and then fed into a methane cracking hydrogen production reactor.

[0013] Furthermore, the cracking reaction catalyst is a mixture of one or more components selected from solid carbon, molten metal, and molten salt.

[0014] Commonly used methane cracking catalyst metals are copper, tin, nickel, bismuth, or a mixture of several metals, with a melting point of around 1000°C.

[0015] When solid carbon is used as a catalyst, the methane cracking reactor is a fluidized bed and methane still exists in the catalyst in the form of bubbles.

[0016] The cracking reaction catalyst is incompatible with both carbon and hydrogen. After methane is introduced from the bottom of the methane cracking hydrogen production reactor, it flows upward in the cracking reaction catalyst in the form of bubbles. Under high temperature conditions, a catalytic cracking reaction occurs at the interface between the cracking reaction catalyst and the methane bubbles, and a non-catalytic thermal cracking reaction occurs inside the methane bubbles. In addition, the density of the cracking reaction catalyst is greater than that of methane, carbon and hydrogen. The methane bubbles float upward while undergoing a cracking reaction. Methane, carbon and hydrogen will eventually float above the liquid surface of the cracking reaction catalyst, and the cracking reaction catalyst will not be carried away from the methane cracking hydrogen production reactor.

[0017] This invention couples methane cracking hydrogen production technology with a SOFC power generation system. This system utilizes SOFC waste heat and hydrogen to provide heat for the methane cracking hydrogen production process. The carbon products from methane cracking hydrogen production are separated from the hydrogen, eliminating carbon emissions. The hydrogen is then transported to the SOFC system for power generation. This invention enables near-zero-carbon methane-fueled SOFC power generation technology, while also requiring minimal water consumption and complexity. The carbon products, a high-value-added industrial raw material, enhance the system's economic efficiency.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] (1) The hydrogen production process of the present invention is simple. Methane can be used to produce hydrogen in only one step without consuming additional water resources. The hydrogen and carbon products can be separated by gravity.

[0020] (2) The present invention can achieve near-zero carbon emissions and high economic benefits. The carbon product of the methane cracking hydrogen production reaction is solid, the separation process is simple, and the carbon product can be used as an industrial raw material. It is a high-value-added product that can effectively reduce the power generation cost of the system.

[0021] (3) The present invention has low energy consumption. When producing hydrogen from the same amount of methane, the energy consumption of direct cracking is lower than that of steam reforming. In addition, the present invention recycles the heat of SOFC tail gas combustion, further improving the energy utilization rate of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the system principle of the present invention;

[0023] In the figure: 1. Methane compressor; 2. Methane cracking hydrogen production reactor; 3. Cracking reaction catalyst; 4. Methane bubbles; 5. Air compressor 1; 6. Air preheater; 7. Solid oxide fuel cell power generation module; 8. Tail gas burner; 9. Afterburner; 10. Air compressor 2; 11. Methane cracking hydrogen production reactor casing; 12. Hydrogen-carbon separator; 13. Carbon products; 14. Three-way valve. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0025] like Figure 1 As shown, a power generation system of methane cracking hydrogen production coupled with solid oxide fuel cells is characterized in that it includes a solid oxide fuel cell power generation module 7, a methane cracking hydrogen production module, a supplementary combustion module, and an air preheating module; methane gas passes through the methane cracking hydrogen production module to produce hydrogen, and the produced hydrogen is respectively sent to the solid oxide fuel cell power generation module 7 and the supplementary combustion module through a three-way valve 14 to participate in the reaction; the air preheating module preheats the air and then sends it to the solid oxide fuel cell power generation module 7 to participate in the reaction; the supplementary combustion module sends the high-temperature gas generated after the reaction of hydrogen and air to the methane cracking hydrogen production module to provide heat to the methane cracking hydrogen production module;

[0026] The solid oxide fuel cell power generation module 7 includes an anode and a cathode, hydrogen and air are fed into the anode and the cathode respectively and electrochemical reactions occur to generate electricity;

[0027] The methane cracking hydrogen production module includes a methane cracking hydrogen production reactor 2, a cracking reaction catalyst 3, a methane cracking hydrogen production reactor sleeve 11, and a hydrogen-carbon separator 12. The methane cracking hydrogen production reactor sleeve 11 is attached to the outer wall of the methane cracking hydrogen production reactor 2, and the cracking reaction catalyst 3 is placed in the methane cracking hydrogen production reactor 2. Methane gas is fed into the methane cracking hydrogen production reactor 2 from the bottom and reacts with the cracking reaction catalyst 3 during the gradual floating process. The densities of methane, carbon and hydrogen are all less than the density of the cracking reaction catalyst 3, so that the reaction products of the methane cracking hydrogen production module float to the top of the cracking reaction catalyst 3 and are separated by the hydrogen-carbon separator 12. The separated hydrogen is respectively transported to the solid oxide fuel cell power generation module 7 and the supplementary combustion module through the three-way valve 14.

[0028] Furthermore, methane gas forms methane bubbles 4 in the cracking reaction catalyst 3. After the cracking reaction catalyst 3 and the methane bubbles 4 are heated, the methane bubbles 4 undergo a cracking reaction under the action of the high temperature environment and the catalyst: CH4→C+2H2, the carbon product 13 is recovered, and the hydrogen is distributed according to demand through the three-way valve 14.

[0029] Furthermore, it also includes an exhaust gas combustion module, which includes an exhaust gas burner 8. The hydrogen remaining at the anode outlet of the solid oxide fuel cell power generation module 7 is mixed with the air remaining at the cathode outlet and burned to produce high-temperature exhaust gas, and the high-temperature gas is sent to the supplementary combustion module.

[0030] Furthermore, the afterburner module includes an afterburner 9, the tail gas burner 8 generates high-temperature tail gas which is fed into the afterburner 9, and the air compressor 2 10 compresses the air and feeds it into the afterburner 9. The high-temperature tail gas generated by the tail gas burner 8, the air compressed by the air compressor 2 10, and the hydrogen generated by the methane cracking hydrogen production module burn and react in the afterburner 9 to further increase the temperature of the high-temperature tail gas. The high-temperature gas generated by the combustion of the afterburner 9 is fed into the methane cracking hydrogen production reactor casing 11 to provide heat to the methane cracking hydrogen production reactor 2.

[0031] Furthermore, the air preheating module includes an air preheater 6. The air compressor 5 compresses the air and sends it into the air preheater 6. The exhaust gas at the outlet of the methane cracking hydrogen production reactor sleeve 11 is sent to the air preheater 6 for preheating the compressed air. The exhaust gas after passing through the air preheater 6 is discharged into the atmospheric environment.

[0032] Furthermore, the methane gas is compressed by the methane compressor 1 and then fed into the methane cracking hydrogen production reactor 2 .

[0033] Furthermore, the cracking reaction catalyst 3 is a mixture of one or more components selected from solid carbon, molten metal, and molten salt.

[0034] Commonly used methane cracking catalyst metals are copper, tin, nickel, bismuth, or a mixture of several metals, with a melting point of around 1000°C.

[0035] When solid carbon is used as a catalyst, the methane cracking reactor is a fluidized bed and methane still exists in the catalyst in the form of bubbles.

[0036] The cracking reaction catalyst 3 is incompatible with both carbon and hydrogen. After methane is introduced from the bottom of the methane cracking hydrogen production reactor 2, it flows upward in the cracking reaction catalyst 3 in the form of bubbles. Under high temperature conditions, a catalytic cracking reaction occurs at the interface between the cracking reaction catalyst 3 and the methane bubbles, and a non-catalytic thermal cracking reaction occurs inside the methane bubbles. Moreover, the density of the cracking reaction catalyst is greater than that of methane, carbon, and hydrogen. The methane bubbles float upward while undergoing a cracking reaction. Methane, carbon, and hydrogen will eventually float above the liquid surface of the cracking reaction catalyst 3, and the cracking reaction catalyst 3 will not be carried away from the methane cracking hydrogen production reactor 2.

[0037] The above description is only a preferred embodiment of the present invention and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A power generation system of methane cracking to produce hydrogen coupled with solid oxide fuel cells, characterized in that: It comprises a solid oxide fuel cell power generation module (7), a methane cracking hydrogen production module, a supplementary combustion module, and an air preheating module; methane gas is passed through the methane cracking hydrogen production module to produce hydrogen, and the produced hydrogen is respectively sent to the solid oxide fuel cell power generation module (7) and the supplementary combustion module through a three-way valve (14) to participate in the reaction; the air preheating module preheats the air and sends it to the solid oxide fuel cell power generation module (7) to participate in the reaction; the supplementary combustion module sends the high-temperature gas generated after the reaction of hydrogen and air to the methane cracking hydrogen production module to provide heat to the methane cracking hydrogen production module; The solid oxide fuel cell power generation module (7) comprises an anode and a cathode, hydrogen and air are fed into the anode and the cathode respectively and electrochemical reactions occur to generate electricity; The methane cracking hydrogen production module comprises a methane cracking hydrogen production reactor (2), a cracking reaction catalyst (3), a methane cracking hydrogen production reactor sleeve (11), and a hydrogen-carbon separator (12). The methane cracking hydrogen production reactor sleeve (11) is attached to the outer wall of the methane cracking hydrogen production reactor (2), the cracking reaction catalyst (3) is placed in the methane cracking hydrogen production reactor (2), and methane gas is fed into the methane cracking hydrogen production reactor (2) from the bottom and reacts with the cracking reaction catalyst (3) during the gradual floating process. The densities of methane, carbon, and hydrogen are all less than the density of the cracking reaction catalyst (3), so that the reaction product of the methane cracking hydrogen production module floats to the top of the cracking reaction catalyst (3) and is separated by the hydrogen-carbon separator (12). The separated hydrogen is respectively transported to the solid oxide fuel cell power generation module (7) and the supplementary combustion module through a three-way valve (14).

2. The power generation system of methane cracking and hydrogen production coupled with solid oxide fuel cells according to claim 1, characterized in that: Methane gas forms methane bubbles (4) in the cracking reaction catalyst (3). After the cracking reaction catalyst (3) and the methane bubbles (4) are heated, the methane bubbles (4) undergo a cracking reaction under the action of the high temperature environment and the catalyst: CH4→C+2H2.

3. The power generation system of methane cracking to produce hydrogen coupled with solid oxide fuel cells according to claim 1, characterized in that: The invention also includes an exhaust gas combustion module, which includes an exhaust gas burner (8). The hydrogen remaining at the anode outlet of the solid oxide fuel cell power generation module (7) is mixed with the air remaining at the cathode outlet and burned to generate high-temperature exhaust gas, and the high-temperature gas is sent to the supplementary combustion module.

4. The power generation system of methane cracking and hydrogen production coupled with solid oxide fuel cells according to claim 3, characterized in that: The afterburning module includes an afterburner (9), an exhaust burner (8) generates high-temperature exhaust gas which is fed into the afterburner (9), an air compressor 2 (10) compresses air and feeds it into the afterburner (9), the exhaust burner (8) generates high-temperature exhaust gas, the air compressed by the air compressor 2 (10), and the hydrogen generated by the methane cracking hydrogen production module undergo combustion reaction in the afterburner (9), and the high-temperature gas generated by the combustion of the afterburner (9) is fed into the methane cracking hydrogen production reactor casing (11) to provide heat to the methane cracking hydrogen production reactor (2).

5. The power generation system of methane cracking and hydrogen production coupled with solid oxide fuel cells according to claim 4, characterized in that: The air preheating module includes an air preheater (6), an air compressor (5) compresses the air and sends it into the air preheater (6), the tail gas at the outlet of the methane cracking hydrogen production reactor sleeve (11) is sent into the air preheater (6) for preheating the compressed air, and the tail gas after passing through the air preheater (6) is discharged into the atmosphere.

6. The power generation system of methane cracking to produce hydrogen coupled with solid oxide fuel cells according to claim 1, characterized in that: The methane gas is compressed by the methane compressor (1) and then sent to the methane cracking hydrogen production reactor (2).

7. The power generation system of methane cracking to produce hydrogen coupled with solid oxide fuel cells according to claim 1, characterized in that: The cracking reaction catalyst (3) is a mixture of one or more components selected from solid carbon, molten metal, and molten salt.

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