Gas-electricity combined supply system based on LNG (Liquefied Natural Gas) and solid oxide fuel cell

Abstract

The utility model relates to a gas-electricity combined supply system based on LNG (Liquefied Natural Gas) and a solid oxide fuel cell, which comprises a cold energy primary utilization device and the solid oxide fuel cell, a condensation heat exchanger, a reformer and a first heat exchanger are sequentially connected between the rewarming device and an electric pile anode gas inlet of the solid oxide fuel cell, and an electric pile anode gas outlet of the solid oxide fuel cell is sequentially connected with the condensation heat exchanger, a water removal device, an LNG-CO2 desublimation device and a CO2 collection device; the LNG-CO2 desublimation device is connected with the cold energy primary utilization device and the rewarming device, a stack cathode gas inlet of the solid oxide fuel cell is sequentially connected with a second heat exchanger and an air compressor, and a stack cathode gas outlet of the solid oxide fuel cell is sequentially connected with a first heat exchanger and a tail gas burner; and a third heat exchanger forming a circulation loop with the rewarming device is further arranged. The device has the advantages of being simple in structure, convenient to operate and control, safe and reliable.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of energy supply systems, specifically to a kind of gas-electricity cogeneration system based on LNG and solid oxide fuel cell. BACKGROUND

[0002] Natural gas solid oxide fuel cell is a kind of potential, environmental protection efficient energy supply equipment, it uses electrochemical reaction to generate electricity, and flue gas after reaction can provide heat by waste heat recovery.Solid oxide fuel cell reduces the carbon dioxide emission of unit power generation by improving energy efficiency, but due to the use of natural gas, a certain amount of carbon dioxide emission is generated, which needs to adopt carbon capture method to treat exhaust and recover carbon dioxide.At present, the main way in the field is to mix pure oxygen and anode exhaust to improve the concentration of carbon dioxide, and then carbon dioxide capture is carried out, because oxygen needs to be prepared or purchased separately, which causes the cost of this way to be larger.There is also a way, using combustion reforming heat exchanger and realizing the reforming reaction of methane and water through chemical chain combustion, so that the unreacted carbon monoxide and hydrogen in the anode exhaust of the stack are converted into carbon dioxide and water to improve the concentration of carbon dioxide in the anode exhaust, and then carbon dioxide capture is carried out, because the heat balance in the solid oxide fuel cell is a complex control system itself, and the channel switching control in the combustion reforming heat exchanger is added, which increases the complexity of the control system and the difficulty of actual operation. SUMMARY

[0003] The utility model aims at providing a kind of gas-electricity cogeneration system based on LNG and solid oxide fuel cell, it has the advantages such as simple structure, easy to operate, high energy utilization rate, safe and reliable.

[0004] In order to solve the above problems in the prior art, the utility model provides a kind of gas-electricity combined heat and power system based on LNG and solid oxide fuel cell, including cold energy primary utilization device and solid oxide fuel cell, the input of cold energy primary utilization device is connected with LNG storage device, the output of cold energy primary utilization device is connected with rewarming device by being equipped with the preheating pipeline of first control valve, condensing heat exchanger, reformer and first heat exchanger are sequentially connected between the output of rewarming device and the anode gas inlet of the electric pile of solid oxide fuel cell by anode gas supply pipeline, gas pipeline leading to natural gas user is connected to anode gas supply pipeline between rewarming device and condensing heat exchanger, the anode exhaust of the electric pile of solid oxide fuel cell is sequentially connected with water removal device, LNG-CO2 desublimation device and CO2 collection device after being connected condensing heat exchanger by anode exhaust pipeline, condensing heat exchanger is connected with vaporizer by condensing water pipeline, vaporizer is connected with reformer by steam pipeline, LNG-CO2 desublimation device is connected with the output of cold energy primary utilization device and the input of rewarming device by desublimation gas inlet pipeline and desublimation gas outlet pipeline, second control valve is equipped on desublimation gas inlet pipeline, LNG-CO2 desublimation device is connected with tail gas burner by tail gas pipeline, tail gas burner is connected with vaporizer by first high-temperature flue gas pipeline, the cathode gas inlet of the electric pile of solid oxide fuel cell is sequentially connected with second heat exchanger and air compressor by cathode gas supply pipeline, second heat exchanger is connected with tail gas burner by second high-temperature flue gas pipeline, the cathode exhaust of the electric pile of solid oxide fuel cell is sequentially connected with first heat exchanger and tail gas burner by cathode exhaust pipeline, the electric energy generated by solid oxide fuel cell is delivered to electric user by power supply line;It also includes third heat exchanger, first exhaust gas pipeline is equipped between third heat exchanger and vaporizer, first exhaust gas pipeline is communicated with first high-temperature flue gas pipeline by the heating channel of vaporizer, first exhaust gas pipeline is connected with second heat exchanger by second exhaust gas pipeline, second exhaust gas pipeline is communicated with second high-temperature flue gas pipeline by the heat exchange channel of second heat exchanger, circulation loop is equipped between third heat exchanger and rewarming device, water pump for driving working medium flow is equipped in circulation loop.

[0005] Further, the utility model discloses a kind of gas-electricity combined heat and power system based on LNG and solid oxide fuel cell, wherein, the condensing heat exchanger is used to carry out heat exchange to the natural gas and anode exhaust that enter, and the condensing water generated is delivered to vaporizer, the LNG-CO2 desublimation device is used to carry out heat exchange to the natural gas and anode exhaust that enter, and CO2 and anode tail gas formed after anode exhaust desublimation are correspondingly delivered to CO2 collection device and tail gas burner.

[0006] Further, the utility model provides a kind of gas-electricity combined supply system based on LNG and solid oxide fuel cell, wherein, the rewarming device is used to heat the natural gas that flows, the reformer is used to carry out reforming reaction to the natural gas and water vapor that enter, and carbon monoxide and hydrogen generated by reforming reaction are delivered to first heat exchanger by anode gas supply pipeline.

[0007] Further, the utility model provides a kind of gas-electricity combined supply system based on LNG and solid oxide fuel cell, wherein, the water removal device is used to remove water in anode exhaust, the CO2 collection device is used to collect CO2 obtained by sublimation of anode exhaust by LNG-CO2 sublimation device, and the air compressor is used to compress air.

[0008] Further, the utility model provides a kind of gas-electricity combined supply system based on LNG and solid oxide fuel cell, wherein, the vaporizer is used to vaporize water and deliver generated water vapor to reformer by steam pipeline, the tail gas burner is used to burn anode tail gas and cathode exhaust that enter, and high-temperature flue gas generated by burning is delivered to vaporizer and second heat exchanger by first high-temperature flue gas pipeline and second high-temperature flue gas pipeline respectively.

[0009] Further, the utility model provides a kind of gas-electricity combined supply system based on LNG and solid oxide fuel cell, wherein, the first heat exchanger is used to exchange heat to the natural gas or reforming gas and cathode exhaust that enter, the second heat exchanger is used to exchange heat to the air and high-temperature flue gas that enter, and the third heat exchanger is used to exchange heat to the exhaust gas and working medium that enter.

[0010] The utility model discloses a kind of gas-electricity combined supply system based on LNG and solid oxide fuel cell compared with prior art, with the following advantages: the utility model is connected by being arranged cold energy primary utilization device and solid oxide fuel cell, the input of cold energy primary utilization device is connected with LNG storage device, the output of cold energy primary utilization device is connected with rewarming device by being arranged first control valve preheating pipeline, condensing heat exchanger, reformer and first heat exchanger are sequentially connected between the output of rewarming device and the anode gas inlet of the stack of solid oxide fuel cell by anode gas supply pipeline, and the anode gas supply pipeline between rewarming device and condensing heat exchanger is connected to the gas pipeline leading to natural gas user, the stack of solid oxide fuel cell is sequentially connected with water removal device, LNG-CO2 desublimation device and CO2 collection device after being connected condensing heat exchanger by anode exhaust pipe, wherein condensing heat exchanger is connected with vaporizer by condensing water pipeline, vaporizer is connected with reformer by steam pipeline, LNG-CO2 desublimation device is connected with the output of cold energy primary utilization device and the input of rewarming device by desublimation gas inlet pipe and desublimation gas outlet pipe, second control valve is arranged on desublimation gas inlet pipe, LNG-CO2 desublimation device is connected with tail gas combustor by tail gas pipeline, tail gas combustor is connected with vaporizer by first high-temperature flue gas pipeline, the stack of solid oxide fuel cell is sequentially connected with second heat exchanger and air compressor by cathode gas supply pipeline by cathode gas inlet, and second heat exchanger is connected with tail gas combustor by second high-temperature flue gas pipeline, the stack of solid oxide fuel cell is sequentially connected with first heat exchanger and tail gas combustor by cathode exhaust pipe by cathode gas outlet, and the electric energy generated by solid oxide fuel cell is sent to electric user by power supply line;Third heat exchanger is also arranged, wherein first exhaust pipe is arranged between third heat exchanger and vaporizer, first exhaust pipe is communicated with first high-temperature flue gas pipeline by heating channel of vaporizer, first exhaust pipe is connected with second heat exchanger by second exhaust pipe, second exhaust pipe is communicated with second high-temperature flue gas pipeline by heat exchange channel of second heat exchanger, circulation loop is arranged between third heat exchanger and rewarming device, and water pump for driving working medium flow is arranged in circulation loop.Thus, a gas-electricity combined supply system based on LNG and solid oxide fuel cell is formed, which has simple structure, convenient operation, high energy utilization rate and safety and reliability. In actual application, the solid oxide fuel cell needs to be preheated before power generation, because the stack temperature of the solid oxide fuel cell needs to reach 600 DEG C or above to start power generation. The second control valve is closed, the first control valve is opened, the LNG is treated by the cold energy primary utilization device to become gaseous natural gas, the natural gas enters the reheating device, and then sequentially flows through the condensing heat exchanger, the reformer, the first heat exchanger, the stack anode of the solid oxide fuel cell, the condensing heat exchanger, the water removal device and the LNG-CO2 condensation device and enters the tail gas burner. Meanwhile, the air is compressed and then sequentially flows through the second heat exchanger, the stack cathode of the solid oxide fuel cell and the first heat exchanger and enters the tail gas burner. The natural gas and the air are mixed and combusted in the tail gas burner, the high-temperature flue gas generated by the combustion is correspondingly delivered to the vaporizer and the second heat exchanger through the first high-temperature flue gas pipeline and the second high-temperature flue gas pipeline, the water in the vaporizer is heated by the high-temperature flue gas to become water vapor, the water vapor enters the reformer and performs a reforming reaction with the flowing natural gas, the mixed gas generated by the reforming reaction heats the stack anode of the solid oxide fuel cell when flowing through the stack anode, the high-temperature flue gas in the second heat exchanger exchanges heat with the air, the air with increased temperature heats the stack cathode of the solid oxide fuel cell when flowing through the stack cathode, and the solid oxide fuel cell is heated and heated in a cycle through the above steps. When the stack temperature of the solid oxide fuel cell reaches 600 DEG C or above, normal power generation and gas supply can be performed. The first control valve is closed, the second control valve is opened, the LNG is treated by the cold energy primary utilization device to become gaseous natural gas, the natural gas flows through the LNG-CO2 condensation device and enters the reheating device, a part of the natural gas heated by the reheating device is delivered to a natural gas user through the gas pipeline, a part of the natural gas flows through the condensing heat exchanger and enters the reformer to perform a reforming reaction with the water vapor from the vaporizer, the mixed gas generated by the reforming reaction flows through the first heat exchanger and enters the stack anode of the solid oxide fuel cell, the air is compressed and flows through the second heat exchanger and enters the stack cathode of the solid oxide fuel cell, the stack of the solid oxide fuel cell generates electricity through an electrochemical reaction, and the generated electric energy is delivered to an electric user through the power supply line.The utility model discloses a gas and electricity combined supply system based on LNG and solid oxide fuel cell, utilize low temperature natural gas (-100 DEG C around) after the processing of cold energy first utilization device, carry out capture and purification to the high concentration carbon dioxide (more than 50%) after the condensation and water removal in solid oxide fuel cell anode exhaust, not only realize the ladder utilization of LNG cold energy, improve the cold energy utilization efficiency effectively, and realize the capture and purification of carbon dioxide in solid oxide fuel cell anode exhaust, the utility model makes full use of the characteristics that the natural gas temperature after gasification is still low, carries out heat exchange to the low temperature natural gas of solid oxide fuel cell and anode exhaust (contains a large amount of carbon dioxide, water vapor and a small amount of carbon monoxide and hydrogen) in condensing heat exchanger, recovers the condensed water in anode exhaust using the cold quantity of low temperature natural gas, on one hand, condensed water enters the vaporizer and is used for reforming reaction, reduces the external additional water supply, on the other hand, the moisture in anode exhaust is separated after condensation, and the concentration of carbon dioxide is improved, which is beneficial to improve the capture and purification efficiency and reduce the cost, the utility model discloses anode exhaust (contains unreacted carbon monoxide and hydrogen) formed after carbon dioxide capture separation and cathode exhaust are mixed and combusted in tail gas combustor, and the high temperature flue gas produced by combustion is supplied to vaporizer and second heat exchanger respectively, on the basis of maintaining the temperature required by the electric pile reaction of solid oxide fuel cell, carbon dioxide capture separation is realized, and the incombustible combustible gas is combusted and treated, and the safety of external exhaust is ensured, the utility model discloses the third heat exchanger is arranged, and the exhaust gas formed after high temperature flue gas exchanges heat with water and air exchanges heat respectively in the third heat exchanger, and the working medium exchanges heat in the third heat exchanger, the working medium flows in the circulation loop and transfers heat to the temperature recovery device, and the energy consumption of temperature recovery device is reduced.

[0011] The gas and electricity combined supply system based on LNG and solid oxide fuel cell will be further explained in detail in combination with the specific embodiment shown in the drawings. DRAWINGS

[0012] Figure 1 It is a structure schematic view of the gas and electricity combined supply system based on LNG and solid oxide fuel cell. SPECIFIC EMBODIMENT

[0013] First of all, the up, down, left, right, front, back and other directional words in the utility model are described according to the drawings for the convenience of understanding, and not for the limitation of the technical scheme and the protection scope of the utility model.

[0014] For example, Figure 1The utility model discloses a kind of gas-electricity combined supply systems based on LNG and solid oxide fuel cell, including cold energy primary utilization device 1 and solid oxide fuel cell 2.Cold energy primary utilization device 1 is connected with LNG storage device to input, cold energy primary utilization device 1 is connected with preheating pipeline that is equipped with first control valve to output, and between the output of rewarmer 3 and the anode gas inlet of the electric pile of solid oxide fuel cell 2, anode gas supply pipeline is sequentially connected condensing heat exchanger 4, reformer 5 and first heat exchanger 6, wherein, anode gas supply pipeline between rewarmer 3 and condensing heat exchanger 4 is connected with the gas pipeline leading to natural gas user.Cold energy primary utilization device 1 is connected with LNG-CO2 desublimation device 8 and CO2 collection device 9 sequentially with water removal device 7, LNG-CO2 desublimation device 8 after being connected with condensing heat exchanger 4 through anode exhaust pipe, wherein, condensing heat exchanger 4 is connected with vaporizer 10 through condensing water pipeline, vaporizer 10 is connected with reformer 5 through steam pipeline, LNG-CO2 desublimation device 8 is connected with the output of cold energy primary utilization device 1 and the input of rewarmer 3 through desublimation gas inlet pipeline and desublimation gas outlet pipeline, second control valve is equipped on desublimation gas inlet pipeline, LNG-CO2 desublimation device 8 is connected with tail gas combustor 11 through tail gas pipeline, and tail gas combustor 11 is connected with vaporizer 10 through first high-temperature flue gas pipeline.Cold energy primary utilization device 1 is connected with air compressor 13 and second heat exchanger 12 sequentially with the cathode gas inlet of the electric pile of solid oxide fuel cell 2 through cathode gas supply pipeline, and make second heat exchanger 12 be connected with tail gas combustor 11 through second high-temperature flue gas pipeline, and make the cathode exhaust pipe of the electric pile of solid oxide fuel cell 2 be connected with first heat exchanger 6 and tail gas combustor 11 sequentially with cathode exhaust pipe.Cold energy primary utilization device 1 is connected with electric user through power supply line, wherein, third heat exchanger 14 is additionally provided to improve energy efficiency ratio and reduce energy consumption, wherein, first exhaust pipe is equipped between third heat exchanger 14 and vaporizer 10, first exhaust pipe is communicated with first high-temperature flue gas pipeline through the heating channel of vaporizer 10, first exhaust pipe is connected with second heat exchanger 12 through second exhaust pipe, second exhaust pipe is communicated with second high-temperature flue gas pipeline through the heat exchange channel of second heat exchanger 12, circulation loop is equipped between third heat exchanger 14 and rewarmer 3, and water pump 15 for driving working medium flow is equipped in circulation loop.

[0015] The above setting constitutes a gas-electricity combined system based on LNG and solid oxide fuel cell, which is simple in structure, convenient in operation, high in energy utilization rate and safe and reliable. In actual application, the solid oxide fuel cell 2 needs to be preheated before power generation, because the stack temperature of the solid oxide fuel cell 2 needs to reach 600℃ or above to start power generation. To this end, the second control valve is closed, the first control valve is opened, the LNG is processed by the cold energy primary utilization device 1 into gaseous natural gas (-100℃ or so), the natural gas enters the rewarming device 3, is heated, and then flows through the condensing heat exchanger 4, the reformer 5, the first heat exchanger 6, the stack anode of the solid oxide fuel cell 2, the condensing heat exchanger 4, the water removal device 7 and the LNG-CO2 condensation device 8 and enters the tail gas combustor 11. Meanwhile, the air is compressed and then flows through the second heat exchanger 12, the stack cathode of the solid oxide fuel cell 2 and the first heat exchanger 6 and enters the tail gas combustor 11. The natural gas and the air are mixed and combusted in the tail gas combustor 11, the high-temperature flue gas generated by the combustion is correspondingly delivered to the vaporizer 10 and the second heat exchanger 12 through the first high-temperature flue gas pipeline and the second high-temperature flue gas pipeline, the water in the vaporizer is heated by the high-temperature flue gas into water vapor, the water vapor enters the reformer 5 and is reformed with the flowing natural gas, the mixed gas (carbon monoxide and hydrogen generated by the reaction, and unreacted natural gas and water vapor) generated after the reforming reaction heats the stack anode of the solid oxide fuel cell 2, the high-temperature flue gas in the second heat exchanger 12 exchanges heat with the air, the air heated by the heat exchange flows through the stack cathode of the solid oxide fuel cell 2, and the above steps can realize the cyclic heating and temperature rising of the solid oxide fuel cell 2. When the stack temperature of the solid oxide fuel cell 2 reaches 600℃ or above, the normal power generation and gas supply can be realized. To this end, the first control valve is closed, the second control valve is opened, the LNG is processed by the cold energy primary utilization device 1 into gaseous natural gas (-100℃ or so), the natural gas flows through the LNG-CO2 condensation device 8 and enters the rewarming device 3, a part of the natural gas heated by the rewarming device 3 is delivered to the natural gas user through the gas pipeline, a part of the natural gas flows through the condensing heat exchanger 4, enters the reformer 5 and is reformed with the water vapor from the vaporizer 10, the mixed gas (carbon monoxide and hydrogen generated by the reaction, and unreacted natural gas and water vapor) generated after the reforming reaction flows through the first heat exchanger 6 and enters the stack anode of the solid oxide fuel cell 2, the air is compressed and flows through the second heat exchanger 12 and enters the stack cathode of the solid oxide fuel cell 2, the stack of the solid oxide fuel cell 2 generates electricity through the electrochemical reaction, and the generated electric energy is delivered to the electric user through the power supply line.The utility model discloses a gas and electricity combined supply system based on LNG and solid oxide fuel cell, utilize low temperature natural gas (-100 DEG C or so) after the processing of cold energy first utilization device 1, carry out capture and purification to the high concentration carbon dioxide (more than 50%) after the condensation and water removal in solid oxide fuel cell 2 anode exhaust, not only realize the ladder utilization of LNG cold energy, improve the cold energy utilization efficiency effectively, and realize the capture and purification of carbon dioxide in solid oxide fuel cell 2 anode exhaust, the utility model makes full use of the characteristics that the natural gas temperature after gasification is still low, and the low temperature natural gas of entering solid oxide fuel cell 2 and anode exhaust (containing a large amount of carbon dioxide, water vapor and a small amount of carbon monoxide and hydrogen) carry out heat exchange in condensing heat exchanger 4, utilize the cold quantity recovery of low temperature natural gas in the condensate of anode exhaust, on the one hand, make the condensate enter vaporizer 10 and carry out vaporization and be used for reforming reaction, reduce the external additional water supply, on the other hand, the moisture in anode exhaust after condensation separation will make the concentration of carbon dioxide improve, be favorable to improve the capture and purification efficiency, reduce the cost, the utility model discloses through making anode exhaust form anode tail gas (containing unreacted carbon monoxide and hydrogen) after carbon dioxide capture separation and mixing combustion with cathode exhaust in tail gas burner 11, and make the high temperature flue gas produced by combustion supply vaporizer 10 and second heat exchanger 12 respectively, on the basis of maintaining the temperature required by the electric pile reaction of solid oxide fuel cell 2, realize carbon dioxide capture separation to incondensable combustible gas, guarantee the safety of external exhaust, the utility model discloses through setting up third heat exchanger 14, and make the waste gas formed after high temperature flue gas exchanges with water and air in third heat exchanger 14 and the working medium carry out heat exchange, through the working medium flow in the circulation loop and give the heat to the temperature recovery device 3, reduce the energy consumption of temperature recovery device 3. It is needful to explain that, the above-mentioned cold energy first utilization device 1, solid oxide fuel cell 2, temperature recovery device 3, condensing heat exchanger 4, reformer 5, water removal device 7, LNG-CO2 condensation and sublimation device 8, CO2 collection device 9, vaporizer 10 and tail gas burner 11 are the existing equipment in the field, and its structure, principle and connecting mode are well known to the skilled person, and will not be repeated here. In addition, it should be pointed out that the electric energy generated by solid oxide fuel cell 2 is not limited to being delivered to the electric user through the power supply line, but can also be connected to the power grid.

[0016] As the specific embodiment, the functions and roles of each component in the gas-electricity cogeneration system are as follows: the condensing heat exchanger 4 is used for heat exchange of the natural gas and the anode exhaust gas, and the generated condensate is delivered to the vaporizer 10; the LNG-CO2 desublimation device 8 is used for heat exchange of the natural gas and the anode exhaust gas, and the CO2 formed after the anode exhaust gas is desublimated is delivered to the CO2 collecting device 9 and the tail gas combustor 11; the rewarming device 3 is used for warming the flowing natural gas; the reformer 5 is used for reforming reaction of the natural gas and the steam, and the carbon monoxide and the hydrogen generated by the reforming reaction are delivered to the first heat exchanger 6 through the anode gas supply pipeline; the water removal device 7 is used for removing the water in the anode exhaust gas; the CO2 collecting device 9 is used for collecting the CO2 obtained by desublimating the anode exhaust gas through the LNG-CO2 desublimation device; the air compressor 13 is used for compressing the air; the vaporizer 10 is used for vaporizing the water and delivering the generated steam to the reformer 5 through the steam pipeline; the tail gas combustor 11 is used for burning the anode tail gas and the cathode exhaust gas, and delivering the high-temperature flue gas generated by the burning to the vaporizer 10 and the second heat exchanger 12 through the first high-temperature flue gas pipeline and the second high-temperature flue gas pipeline respectively; the first heat exchanger 6 is used for heat exchange of the natural gas or the reforming gas and the cathode exhaust gas, the second heat exchanger 12 is used for heat exchange of the air and the high-temperature flue gas, and the third heat exchanger 14 is used for heat exchange of the exhaust gas and the working medium. The reforming gas refers to the mixed gas generated by the natural gas and the steam after the reforming reaction in the reformer 5.

[0017] The above embodiment only describes the preferred embodiments of the present application, and does not limit the protection scope of the present application. Various modifications made by those skilled in the art according to the technical scheme of the present application shall fall within the protection scope of the present application.

Claims

1. A gas-electric cogeneration system based on LNG and solid oxide fuel cells, characterized in that, The application relates to a LNG cold energy utilization system, which comprises a cold energy primary utilization device (1) and a solid oxide fuel cell (2), the input port of the cold energy primary utilization device (1) is connected with a LNG storage device, the output port of the cold energy primary utilization device (1) is connected with a rewarming device (3) through a preheating pipeline provided with a first control valve, the output port of the rewarming device (3) and the anode gas inlet of the solid oxide fuel cell (2) are connected with a condensing heat exchanger (4), a reformer (5) and a first heat exchanger (6) through an anode gas supply pipeline in sequence, the anode gas supply pipeline between the rewarming device (3) and the condensing heat exchanger (4) is connected with a gas pipeline leading to a natural gas user, the anode exhaust port of the solid oxide fuel cell (2) is connected with the condensing heat exchanger (4) through an anode exhaust pipeline, and then connected with a water removal device (7), a LNG-CO2 desublimation device (8) and a CO2 collection device (9) in sequence, the condensing heat exchanger (4) is connected with a vaporizer (10) through a condensing water pipeline, the vaporizer (10) is connected with the reformer (5) through a steam pipeline, the LNG-CO2 desublimation device (8) is connected with the output port of the cold energy primary utilization device (1) and the input port of the rewarming device (3) through a desublimation gas inlet pipeline and a desublimation gas outlet pipeline, a second control valve is arranged on the desublimation gas inlet pipeline, the LNG-CO2 desublimation device (8) is connected with a tail gas burner (11) through a tail gas pipeline, the tail gas burner (11) is connected with the vaporizer (10) through a first high-temperature flue gas pipeline, the cathode gas inlet of the solid oxide fuel cell (2) is connected with a second heat exchanger (12) and an air compressor (13) through a cathode gas supply pipeline in sequence, the second heat exchanger (12) is connected with the tail gas burner (11) through a second high-temperature flue gas pipeline, the cathode exhaust port of the solid oxide fuel cell (2) is connected with the first heat exchanger (6) and the tail gas burner (11) through a cathode exhaust pipeline in sequence, and the electric energy generated by the solid oxide fuel cell (2) is transmitted to an electric user through a power supply line; the system further comprises a third heat exchanger (14), a first waste gas pipeline is arranged between the third heat exchanger (14) and the vaporizer (10), the first waste gas pipeline communicates with the first high-temperature flue gas pipeline through the heating channel of the vaporizer (10), the first waste gas pipeline is connected with the second heat exchanger (12) through a second waste gas pipeline, the second waste gas pipeline communicates with the second high-temperature flue gas pipeline through the heat exchange channel of the second heat exchanger (12), a circulation loop is arranged between the third heat exchanger (14) and the rewarming device (3), and a water pump (15) for driving the flow of a working medium is arranged in the circulation loop.

2. The gas power co-generation system of claim 1, wherein, The condensing heat exchanger (4) is used for heat exchange of the natural gas and the anode exhaust, and the generated condensing water is transmitted to the vaporizer (10), the LNG-CO2 desublimation device (8) is used for heat exchange of the natural gas and the anode exhaust, and the CO2 formed after the anode exhaust is desublimated and the anode tail gas are transmitted to the CO2 collection device (9) and the tail gas burner (11) correspondingly.

3. The gas power co-generation system of claim 1, wherein, The warming device (3) is used for warming the flowing natural gas, the reformer (5) is used for reforming reaction of the flowing natural gas and water vapor, and the carbon monoxide and hydrogen generated by the reforming reaction are delivered to the first heat exchanger (6) through an anode gas supply pipeline.

4. The gas power co-generation system of claim 1, wherein, The water removal device (7) is used for removing water in the anode exhaust gas, the CO2 collection device (9) is used for collecting CO2 obtained by the LNG-CO2 desublimation device on the anode exhaust gas, and the air compressor (13) is used for compressing air.

5. The gas power co-generation system of claim 1, wherein, The vaporizer (10) is used for vaporizing water and delivering the generated water vapor to the reformer (5) through a steam pipeline, and the tail gas burner (11) is used for burning the flowing anode tail gas and cathode exhaust gas, and delivering the high-temperature flue gas generated by the burning to the vaporizer (10) and the second heat exchanger (12) through a first high-temperature flue gas pipeline and a second high-temperature flue gas pipeline respectively.

6. The gas power co-generation system of claim 1, wherein, The first heat exchanger (6) is used for heat exchange of the flowing natural gas or reforming gas and cathode exhaust gas, the second heat exchanger (12) is used for heat exchange of the flowing air and high-temperature flue gas, and the third heat exchanger (14) is used for heat exchange of the flowing exhaust gas and working medium.

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