Anode off-gas recirculation SOFC power generation system and operation method thereof

Abstract

The present application relates to an anode off-gas recirculation SOFC power generation system and an operation method thereof. The system comprises an SOFC stack module, a catalytic combustor, a start-up combustor, a desulfurizer, a fuel preheater, a reformer, a fuel reheater, a recirculation blower, a steam generator, a condenser, a blower, an air preheater, an electrically controlled valve, a first shut-off valve, a second shut-off valve and a third shut-off valve. In this regard, fuel and air in the catalytic combustor are isolated from each other and exchange heat with each other, flue gas generated by combustion of the fuel and the air is condensed to obtain liquid water and CO₂, and the fuel is unreacted fuel at an outlet of the SOFC stack module. On the basis of the anode off-gas recirculation process, the embodiments of the present application utilize the catalytic combustor to perform catalytic combustion on unreacted fuel at the outlet of the SOFC stack module; the flue gas after combustion is condensed to obtain liquid water and CO₂, so that the SOFC system is independent of external water supply under rated operating conditions, and complete capture of high-purity CO₂ is realized at the same time. Fig. 1

Description

A SOFC power generation system with anode exhaust gas recirculation and its operation method Technical Field

[0001] This application relates to the field of fuel cell system technology, specifically to an SOFC power generation system with anode exhaust gas recirculation and its operation method. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are the most efficient power generation technology among all power generation devices, with a single unit power generation efficiency of over 60%. They can use natural gas, biogas, refinery gas, coke oven gas, etc. as fuel, and do not produce pollutants such as nitrogen oxides and sulfur oxides. The installed capacity of a single system can range from kW to hundreds of kW, and multiple systems can be connected in parallel to reach the MW level. They have broad application prospects in distributed power generation for civil and commercial users such as residences, hotels, hospitals, schools, office buildings, communities, data centers, and communication base stations.

[0003] Currently, mainstream high-power SOFC power generation systems use natural gas as fuel. To extend the stack's lifespan, fuel utilization during power generation is generally controlled below 85%. The anode exhaust gas at the stack outlet still contains a certain concentration of combustible components, which are used to maintain system thermal balance after combustion. However, higher fuel utilization leads to shorter stack lifespan and greater difficulty in evenly distributing fuel among multiple stacks within the system; lower fuel utilization results in reduced system efficiency. In conventional high-power SOFC power generation systems, the fuel at the SOFC stack module outlet does not fully react to generate electricity. The high-temperature flue gas produced after mixing with the high-temperature air at the SOFC stack module outlet in the burner is used to maintain system thermal balance, while avoiding the emission of CO and H2 combustible gases. However, in existing technologies, the flue gas flow rate after the remaining fuel at the stack module outlet is large and the CO2 content is low, resulting in high CO2 capture costs. On the other hand, SOFC power generation systems require steam during operation to prevent CH4 in the reformer and SOFC stack from carbonizing under high-temperature conditions. The recovery, reheating, and evaporation of condensate during CO2 capture increase system complexity and reduce system efficiency. Summary of the Invention

[0004] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0005] This application provides an SOFC power generation system with anode tail gas recirculation and its operation method, which can eliminate the dependence on external water supply under rated operating conditions and achieve the capture of high-purity CO2.

[0006] This application provides the following technical solution:

[0007] In a first aspect, embodiments of this application provide an SOFC power generation system with anode exhaust gas recirculation, including an SOFC stack module, a catalytic burner, an electronically controlled valve, a start-up burner, a desulfurizer, a fuel preheater, a reformer, a fuel reheater, a circulating fan, a steam generator, a condenser, a fan, an air preheater, a first shut-off valve, a second shut-off valve, and a third shut-off valve; the fuel and air in the catalytic burner are isolated from each other and exchange heat, and the flue gas generated by the combustion of the fuel and the air is condensed to obtain liquid water and CO2, and the fuel is the unreacted fuel at the outlet of the SOFC stack module.

[0008] In conjunction with the first aspect, in one embodiment of this application, a portion of the anode tail gas from the SOFC stack module outlet passes sequentially through the electronically controlled valve, the reformer, and the fuel preheater, and then mixes with the desulfurized natural gas before entering the circulating fan and fuel pipeline.

[0009] In conjunction with the first aspect, in one embodiment of this application, the catalytic burner adopts a heat exchange design. The catalytic burner includes a heat exchanger and a catalyst. The heat exchanger includes a fuel channel and an air channel. The fuel channel is provided with a fuel inlet, an O2 inlet, a fuel outlet, and the catalyst for catalytic combustion. The air channel is provided with an air inlet and an air outlet. A portion of the anode exhaust gas from the SOFC stack module outlet enters the fuel channel of the catalytic burner and combusts with O2 under the action of the catalyst, releasing heat. The heat exchanger then heats the air from the SOFC stack module outlet in the air channel.

[0010] In conjunction with the first aspect, in one embodiment of this application, when the system is operating at its rated speed, the first shut-off valve is in the open state and the second shut-off valve is in the closed state. The flue gas from the fuel channel outlet of the catalytic burner passes sequentially through the first shut-off valve, the reformer, and the condenser to react and obtain CO2. The air from the air channel outlet of the catalytic burner passes through the start-up burner and exchanges heat with the air from the fan outlet in the air preheater. The flue gas includes water vapor and CO2.

[0011] In conjunction with the first aspect, in one embodiment of this application, the start-up burner is provided with an ignition device, which is used to activate the start-up burner. The start-up burner burns the fuel and air introduced into the SOFC power generation system so that the temperature inside the catalytic burner reaches the temperature required for catalytic combustion.

[0012] In conjunction with the first aspect, in one embodiment of this application, the reformer is a heat exchange type, the reformer is provided with a cold side channel and a hot side channel, the cold side channel is filled with a reforming catalyst, and the hot side channel is connected to the fuel channel outlet of the catalytic burner and the inlet of the condenser respectively; when the system is in rated operation, the flue gas at the fuel channel outlet of the catalytic burner provides a heat source for the fuel reforming reaction in the cold side channel.

[0013] In conjunction with the first aspect, in one embodiment of this application, the steam generator is electrically heated. During the heating and cooling phases of the SOFC power generation system, the steam flow rate is 2.5 times the fuel flow rate. During the power generation phase of the SOFC power generation system, the steam flow rate is 2 to 3 at the inlet water-to-carbon ratio of the reformer. During the rated power generation phase of the SOFC power generation system, the steam generator is in a closed state.

[0014] In conjunction with the first aspect, in one embodiment of this application, the first shut-off valve is disposed on the pipeline between the fuel channel outlet tee of the catalytic burner and the hot side inlet tee of the reformer, the second shut-off valve is disposed on the pipeline between the flue gas outlet tee of the start-up burner and the hot side inlet tee of the reformer, and the third shut-off valve is disposed on the pipeline between the fuel channel outlet tee of the catalytic burner and the fuel inlet of the start-up burner.

[0015] Secondly, this application provides an operating method for an anode tail gas recirculation SOFC power generation system, applied to the aforementioned anode tail gas recirculation SOFC power generation system. The method includes the following: (1) closing the first shut-off valve of the system, opening the second shut-off valve, the third shut-off valve, and the blower of the system, introducing natural gas into the system, and turning on the circulating blower of the system. When air and the natural gas enter the start-up burner of the system, starting the ignition device in the start-up burner to activate the start-up burner to burn the natural gas; (2) when the temperature of the reformer and the SOFC stack module of the system both exceed 300°C, and the temperature of the fuel pipeline of the system exceeds 150°C, starting the steam generator of the system, supplying water vapor to the system to prevent carbon buildup in the reformer and the SOFC stack module; (3) when the outlet temperature of the fuel channel of the catalytic burner of the system exceeds 550°C, opening the first shut-off valve, introducing O2 into the catalytic burner, and closing the second shut-off valve; (4) when the SOFC stack module reaches the power generation temperature, adjusting the... The flow rate of natural gas, the flow rate of steam, the speed of the circulating fan, and the opening degree of the system's electronically controlled valves are monitored, while the fuel utilization rate of the SOFC stack module is monitored and the flow rate of O2 is adjusted. When the current of the system reaches the rated value, the steam generator is shut down; (5) When the system is in the rated operation stage, CO2 is separated from the condenser of the system; (6) The flow rate of natural gas is adjusted according to the current rate and fuel utilization rate of the SOFC stack module, and the steam generator is turned on and the flow rate of steam is adjusted. (7) When the fuel channel outlet temperature of the catalytic burner drops to 550°C, the second shut-off valve is opened to stop the supply of O2 to the catalytic burner; when the temperature of the reformer and the SOFC stack module both drop to 300°C, the steam generator is shut off; when the temperature of the reformer and the SOFC stack module both drop to 100°C, the circulating fan is shut off, and the supply of natural gas to the system is stopped, and the fan is shut off.

[0016] Compared with the prior art, the advantages of this application are as follows: Based on the anode tail gas recirculation process, the system uses a heat exchange catalytic burner to catalytically burn the unreacted fuel at the outlet of the SOFC stack module. The fuel and air are completely isolated in the catalytic burner but exchange heat with each other. After combustion, the flue gas is condensed to obtain liquid water and high-purity CO2. The SOFC system is free from dependence on external water supply under rated operating conditions, and at the same time, it achieves complete capture of high-purity CO2. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 is a process flow diagram of an SOFC power generation system with anode tail gas recirculation provided in an embodiment of this application;

[0019] Figure reference numerals: SOFC stack module 1; catalytic burner 2; electronically controlled valve 3; start-up burner 4; desulfurizer 5; fuel preheater 6; reformer 7; fuel reheater 8; circulating fan 9; steam generator 10; condenser 11; fan 12; air preheater 13; first shut-off valve 14; second shut-off valve 15; third shut-off valve 16. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] It should be noted that although the flowchart shows a logical order, in some cases, the steps shown or described may be performed in a different order than that shown in the flowchart. The terms "first," "second," etc., used in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the structures, proportions, sizes, etc., depicted in the drawings are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effects and purposes achieved by this application, should still fall within the scope of the technical content disclosed in this application. Similarly, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are only for clarity of description and are not used to limit the scope of implementation of this application. Changes or adjustments in their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of this application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0023] In conventional high-power SOFC power generation systems, the fuel at the SOFC stack module outlet does not fully react to generate electricity. The high-temperature flue gas produced after mixing with the high-temperature air at the SOFC stack module outlet in the burner is used to maintain system thermal balance and simultaneously avoids the emission of CO and H2 combustible gases. However, in existing technologies, the flue gas flow rate after the remaining fuel at the stack module outlet is large and the CO2 content is low, resulting in high CO2 capture costs. Furthermore, SOFC power generation systems require steam during operation to prevent CH4 from carbon deposition in the reformer and SOFC stack under high-temperature conditions. The recovery, reheating, and evaporation of condensate during CO2 capture increases system complexity and reduces system efficiency.

[0024] In view of this, embodiments of this application provide an SOFC power generation system with anode exhaust gas recirculation and an operation method thereof. The power generation system includes an SOFC stack module, a catalytic combustor, an electronically controlled valve, a start-up combustor, a desulfurizer, a fuel preheater, a reformer, a fuel reheater, a circulating fan, a steam generator, a condenser, a blower, an air preheater, a first shut-off valve, a second shut-off valve, and a third shut-off valve. In this system, unreacted fuel from the SOFC stack module outlet can be isolated from and exchange heat with air within the catalytic combustor. The fuel and air then burn, and the resulting flue gas is condensed to obtain liquid water and CO2. Based on the anode tail gas recirculation process, this embodiment utilizes a catalytic burner to catalytically burn the incompletely reacted fuel at the outlet of the SOFC stack module. The fuel and air are completely isolated within the catalytic burner but exchange heat with each other. After combustion, the flue gas is condensed to obtain liquid water and high-purity CO2. Under rated operating conditions, the SOFC system is freed from dependence on external water supply and achieves complete capture of high-purity CO2.

[0025] The specific embodiments of this application will now be described in conjunction with the accompanying drawings:

[0026] As shown in Figure 1, this application provides an SOFC power generation system with anode exhaust gas recirculation. The system includes an SOFC stack module 1, a catalytic combustor 2, an electronically controlled valve 3, a start-up combustor 4, a desulfurizer 5, a fuel preheater 6, a reformer 7, a fuel reheater 8, a circulating fan 9, a steam generator 10, a condenser 11, a fan 12, an air preheater 13, a first shut-off valve 14, a second shut-off valve 15, and a third shut-off valve 16. The SOFC stack module 1 is a modular structure composed of multiple SOFC cells combined through specific connection and packaging methods. This module is the core component of the solid oxide fuel cell system, used to directly convert the chemical energy of the fuel into electrical energy. Based on the anode tail gas recirculation process, this system uses a heat-exchange catalytic burner 2 to catalytically burn the incompletely reacted fuel at the outlet of SOFC stack module 1. The fuel and air are completely isolated in the catalytic burner 2 but exchange heat with each other. After combustion, the flue gas is condensed to obtain liquid water and high-purity CO2. Under rated operating conditions, this system eliminates the dependence on external water supply and achieves complete capture of high-purity CO2.

[0027] In one embodiment, during system operation, a portion of the anode tail gas from the outlet of SOFC stack module 1 can sequentially pass through the electronically controlled valve 3, reformer 7, and fuel preheater 6, then mix with fresh, desulfurized natural gas, before entering the circulating fan 9, and finally into the fuel pipeline, thereby achieving the recirculation of the anode tail gas from the outlet of SOFC stack module 1. The flow rate of the anode tail gas entering the circulating pipeline is determined by the opening degree of the electronically controlled valve 3 and the rotational speed of the circulating fan 9.

[0028] In one embodiment, the catalytic combustor 2 can adopt a heat exchange design, consisting of a heat exchanger and a catalyst. The heat exchanger is divided into a fuel passage and an air passage. The fuel passage contains a fuel inlet, a fuel outlet, an O2 inlet, and the catalyst for catalytic combustion; the air passage contains an air inlet and an air outlet. During system operation, a portion of the high-temperature anode exhaust gas from the SOFC stack module 1 outlet can enter the fuel passage of the catalytic combustor 2, where it combusts with O2 under the action of the catalyst, releasing heat, and then heats the high-temperature air from the SOFC stack module 1 outlet in the air passage via the heat exchanger. It is worth noting that the air exchanges heat with the fuel but does not mix with it.

[0029] It is understandable that catalytic burners can completely burn fuel without an open flame, and are unrestricted by fluctuations in fuel flow rate or concentration, but their catalyst operating temperature generally does not exceed 900°C. To facilitate efficient CO2 recovery, the catalytic burner used in this embodiment has a heat exchange function. Fuel and a suitable flow rate of O2 entering the fuel channel can be completely burned, producing only CO2 and water vapor. The air in the air channel is used to cool the catalyst. This achieves both complete fuel combustion without overheating and the production of high-temperature flue gas free of N2 and O2, which contributes to the efficient capture of CO2.

[0030] In one embodiment, when the system is running at rated speed, the first shut-off valve 14 is open and the second shut-off valve 15 is closed. The flue gas composed of water vapor and CO2 at the fuel channel outlet of the catalytic burner 2 passes through the first shut-off valve 14, the reformer 7, and the condenser 11 successively to finally obtain high-purity CO2; the high-temperature air at the air channel outlet of the catalytic burner 2 passes through the start-up burner 4, exchanges heat with the ambient temperature air at the outlet of the fan 12 in the air preheater 13, and finally goes to the waste heat recovery device.

[0031] In one embodiment, the starter burner 4 has a built-in ignition device. When the SOFC power generation system is in a cold start state, the fuel and air introduced can be gathered into the starter burner 4 for combustion. The high-temperature flue gas generated by combustion can be used to heat the system until the catalytic burner 2 reaches the temperature required for catalytic combustion.

[0032] In one embodiment, the reformer 7 can be designed with heat exchange, and it has a cold-side channel and a hot-side channel. The cold-side channel is filled with reforming catalyst, while the hot-side channel is connected to the fuel channel outlet of the catalytic burner 2 and the inlet of the condenser 11, respectively. When the system is under rated operating conditions, the high-temperature flue gas from the fuel channel outlet of the catalytic burner 2 can serve as a heat source for the fuel reforming reaction within the cold-side channel of the reformer 7, thereby ensuring that the composition at the outlet of the reformer 7 meets the requirements of the SOFC stack module 1.

[0033] In one embodiment, the steam generator 10 can be electrically heated and used for heating, cooling, and low-current power generation in the SOFC system, thereby preventing carbon buildup in the reformer 7 and SOFC stack module 1. Specifically, during the heating and cooling phases of the SOFC system, the steam flow rate is set to 2.5 times the fuel flow rate; during the power generation phase of the SOFC system, the steam flow rate decreases as the power generation current of the SOFC stack module 1 increases, and the water-to-carbon ratio at the reformer 7 inlet should be maintained between 2 and 3; while during the rated power generation phase of the SOFC system, the steam generator 10 is in a closed state.

[0034] In one embodiment, in the system, a first shut-off valve 14 is disposed on the pipeline between the fuel channel outlet tee of the catalytic burner 2 and the hot side inlet tee of the reformer 7, a second shut-off valve 15 is disposed on the pipeline between the flue gas outlet tee of the start-up burner 4 and the hot side inlet tee of the reformer 7, and a third shut-off valve 16 is disposed on the pipeline between the fuel channel outlet tee of the catalytic burner 2 and the fuel inlet of the start-up burner 4.

[0035] In addition, this application also provides an operation method for an anode exhaust gas recirculation SOFC power generation system. This method is applicable to the aforementioned anode exhaust gas recirculation SOFC power generation system, that is, the method can be based on the coordinated operation of various components within the system, and its specific content may include:

[0036] (1) During the cold start phase of the SOFC power generation system, first close the first shut-off valve 14, then open the second shut-off valve 15 and the third shut-off valve 16, and then turn on the blower 12 to introduce natural gas into the system, while simultaneously turning on the circulating blower 9. After air and natural gas enter the starter burner 4, start the ignition device to activate the starter burner 4, so that the natural gas is completely burned, and the heat generated by the combustion is used to heat up the SOFC power generation system.

[0037] (2) During the heating stage of the SOFC power generation system, when the temperature of both the reformer 7 and the SOFC stack module 1 exceeds 300°C and the temperature of the fuel pipeline exceeds 150°C, the steam generator 10 is started to supply steam to the SOFC power generation system to prevent carbon buildup in the reformer 7 and the SOFC stack module 1.

[0038] (3) During the activation stage of the catalytic burner 2, when the temperature at the fuel channel outlet of the catalytic burner 2 exceeds 550°C, the first shut-off valve 14 is opened and O2 is introduced into the catalytic burner 2. The amount of O2 should be just enough to meet the complete catalytic combustion of the fuel. Then the second shut-off valve 15 is closed.

[0039] (4) During the current loading stage, when the SOFC stack module 1 reaches the power generation temperature, the natural gas flow rate is increased, and the steam flow rate, the speed of the circulating fan 9, and the opening of the electronically controlled valve 3 are adjusted. At the same time, the fuel utilization rate of the SOFC stack module 1 is monitored, and the O2 flow rate is adjusted to ensure that the SOFC stack module 1 anode tail gas entering the catalytic burner 2 is completely burned and no O2 remains, ensuring that the current is stable and safely reaches the rated value, and then the steam generator 10 is shut off.

[0040] (5) During the rated operation phase of the system, high-purity CO2 is separated from condenser 11;

[0041] (6) During the current reduction phase, based on the current reduction rate and fuel utilization limit of SOFC stack module 1, reduce the natural gas flow rate, turn on the steam generator 10 and gradually increase the steam flow rate, adjust the speed of the circulating fan 9, the opening degree of the electronic control valve 3 and the flow rate of O2, ensure that the SOFC stack module 1 anode tail gas entering the catalytic burner 2 is completely burned and there is no remaining O2, and ensure that the current is reduced to 0 smoothly.

[0042] (7) During the cooling phase of the system, the cooling operation can be carried out according to the appropriate cooling rate of SOFC stack module 1. When the outlet temperature of the fuel channel of catalytic burner 2 drops to 550°C, the second shut-off valve 15 is opened to stop the supply of O2 into catalytic burner 2; when the temperature of reformer 7 and SOFC stack module 1 drops to 300°C, the steam generator 10 is turned off; when the temperature of reformer 7 and SOFC stack module 1 drops to 100°C, the circulating fan 9 is turned off, the supply of natural gas to the system is stopped, and the fan 12 is turned off.

[0043] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An SOFC power generation system with anode exhaust gas recirculation, comprising an SOFC stack module, a catalytic burner, an electronically controlled valve, a start-up burner, a desulfurizer, a fuel preheater, a reformer, a fuel reheater, a circulating fan, a steam generator, a condenser, a blower, an air preheater, a first shut-off valve, a second shut-off valve, and a third shut-off valve; wherein the fuel and air in the catalytic burner are isolated from each other and exchange heat, and the flue gas generated by the combustion of the fuel and the air is condensed to obtain liquid water and CO2, wherein the fuel is the unreacted fuel at the outlet of the SOFC stack module.

2. The SOFC power generation system with anode tail gas recirculation according to claim 1, characterized in that, A portion of the anode tail gas from the SOFC stack module outlet passes sequentially through the electronically controlled valve, the reformer, and the fuel preheater, and then mixes with the desulfurized natural gas before entering the circulating fan and fuel pipeline.

3. The SOFC power generation system with anode tail gas recirculation according to claim 1, characterized in that, The catalytic combustor adopts a heat exchange design, and includes a heat exchanger and a catalyst. The heat exchanger includes a fuel channel and an air channel. The fuel channel is provided with a fuel inlet, an O2 inlet, a fuel outlet, and the catalyst for catalytic combustion. The air channel is provided with an air inlet and an air outlet. A portion of the anode exhaust gas from the SOFC stack module outlet enters the fuel channel of the catalytic combustor and combusts with O2 under the action of the catalyst, releasing heat. The heat exchanger then heats the air from the SOFC stack module outlet in the air channel.

4. The SOFC power generation system with anode tail gas recirculation according to claim 1, characterized in that, When the system is operating at its rated speed, the first shut-off valve is in the open state and the second shut-off valve is in the closed state. The flue gas from the fuel channel outlet of the catalytic burner passes through the first shut-off valve, the reformer and the condenser in sequence to react and obtain CO2. The air from the air channel outlet of the catalytic burner passes through the start-up burner and exchanges heat with the air from the fan outlet in the air preheater. The flue gas includes water vapor and CO2.

5. The SOFC power generation system with anode tail gas recirculation according to claim 1, characterized in that, The start-up burner is equipped with an ignition device, which is used to activate the start-up burner. The start-up burner burns the fuel and air introduced into the SOFC power generation system to bring the temperature inside the catalytic burner up to the temperature required for catalytic combustion.

6. The SOFC power generation system with anode tail gas recirculation according to claim 1, characterized in that, The reformer is a heat exchange type, and it has a cold side channel and a hot side channel. The cold side channel is filled with a reforming catalyst, and the hot side channel is connected to the fuel channel outlet of the catalytic burner and the inlet of the condenser, respectively. When the system is in rated operation, the flue gas from the fuel channel outlet of the catalytic burner provides a heat source for the fuel reforming reaction in the cold side channel.

7. The SOFC power generation system with anode tail gas recirculation according to claim 1, characterized in that, The steam generator is electrically heated. During the heating and cooling phases of the SOFC power generation system, the steam flow rate is 2.5 times the fuel flow rate. During the power generation phase of the SOFC power generation system, the steam flow rate is 2 to 3 at the inlet water-to-carbon ratio of the reformer. During the rated power generation phase of the SOFC power generation system, the steam generator is in a closed state.

8. The SOFC power generation system with anode tail gas recirculation according to claim 1, characterized in that, The first shut-off valve is installed on the pipeline between the fuel channel outlet tee of the catalytic burner and the hot side inlet tee of the reformer; the second shut-off valve is installed on the pipeline between the flue gas outlet tee of the start-up burner and the hot side inlet tee of the reformer; and the third shut-off valve is installed on the pipeline between the fuel channel outlet tee of the catalytic burner and the fuel inlet of the start-up burner.

9. An operation method for an SOFC power generation system with anode tail gas recirculation, characterized in that, The method, applied to the SOFC power generation system with anode tail gas recirculation according to any one of claims 1-8, comprises the following: (1) Close the first shut-off valve of the system, open the second shut-off valve, the third shut-off valve and the blower of the system, introduce natural gas into the system and turn on the circulating blower of the system. When the air and the natural gas enter the starter burner of the system, start the ignition device in the starter burner to activate the starter burner to burn the natural gas. (2) When the temperature of the reformer and SOFC stack module of the system exceeds 300°C and the temperature of the fuel pipeline of the system exceeds 150°C, start the steam generator of the system to supply water vapor to the system to prevent carbon buildup in the reformer and SOFC stack module. (3) When the fuel passage outlet temperature of the catalytic burner of the system exceeds 550°C, open the first shut-off valve, introduce O2 into the catalytic burner, and close the second shut-off valve. (4) When the SOFC stack module reaches the power generation temperature, adjust the flow rate of the natural gas, the flow rate of the steam, the speed of the circulating fan and the opening of the electronic control valve of the system, while monitoring the fuel utilization rate of the SOFC stack module and adjusting the flow rate of O2. When the current of the system reaches the rated value, shut down the steam generator. (5) When the system is in rated operation, CO2 is separated from the condenser of the system; (6) Adjust the flow rate of natural gas according to the current rate and fuel utilization rate of the SOFC stack module, and turn on the steam generator and adjust the flow rate of water vapor, the speed of the circulating fan, the opening degree of the electronic control valve and the flow rate of O2; (7) When the fuel channel outlet temperature of the catalytic burner drops to 550°C, the second shut-off valve is opened to stop the O2 from being introduced into the catalytic burner; when the temperatures of the reformer and the SOFC stack module both drop to 300°C, the steam generator is shut down; when the temperatures of the reformer and the SOFC stack module both drop to 100°C, the circulating fan is shut down, and the natural gas is stopped from being introduced into the system, and the fan is shut down.