Internal combustion engine-sofc hybrid combined heat and power system, working method and application

Abstract

This invention relates to the field of integrated new energy supply and hybrid power technology, and particularly to an internal combustion engine-SOFC combined heat and power system, its working method, and its application. The system includes an internal combustion engine and a fuel cell; the fuel cell is equipped with an electro-hydraulic supercharging system, which includes a battery compressor; the outlet of the battery compressor is connected to the inlet of the internal combustion engine; the anode outlet of the fuel cell is connected to the inlet of the internal combustion engine, and a steam-water separator and a syngas storage tank are sequentially installed on the connecting pipeline; the outlet of the internal combustion engine and the anode inlet of the fuel cell are connected through two pipelines, one of which is equipped with a carbon dioxide capture device, and the other is equipped with a waste heat boiler. This invention achieves energy coupling between the internal combustion engine and the solid oxide fuel cell stack, on-site carbon recycling, efficient utilization of exhaust waste heat, and improves the transient response speed of the internal combustion engine.

Description

Technical Field

[0001] This invention relates to the field of new energy integrated power supply and composite power technology, and in particular to an internal combustion engine-SOFC combined power supply system, its working method and application. Background Technology

[0002] A hybrid power system consisting of a solid oxide fuel cell (SOFC) and an internal combustion engine (ICE) is mainly used in distributed energy stations, ocean-going vessel propulsion, and integrated energy supply for industrial parks. This type of system combines the high-efficiency power generation characteristics of SOFC with the high-power mechanical output capability of the internal combustion engine: SOFC directly converts the chemical energy of fuel into electrical energy, and its exhaust waste heat can be utilized by the internal combustion engine or used for power generation, while the internal combustion engine is responsible for providing mechanical power, thus achieving multi-stage utilization of fuel as a whole.

[0003] A common SOFC-internal combustion engine hybrid power system typically includes an SOFC stack, an internal combustion engine, a waste heat recovery unit, and a simple exhaust treatment unit. Unburned gas from the SOFC anode enters the internal combustion engine for further combustion, while the engine exhaust is either used to generate steam via a waste heat boiler or discharged directly. Some systems also include a turbocharger to increase the engine's intake pressure. During operation, fuel is first supplied to the SOFC to generate electricity. Residual fuel from the SOFC then enters the internal combustion engine for combustion, driving the engine to output mechanical work. The high-temperature exhaust from the internal combustion engine is then used to generate hot water or steam via a waste heat boiler, achieving combined heat and power (CHP).

[0004] The existing system operates in a fixed mode, unable to flexibly switch its working state according to load changes. Especially under low-load conditions of the internal combustion engine, the exhaust temperature is low and the waste heat quality deteriorates, resulting in a significant decrease in overall energy efficiency. Carbon dioxide in the internal combustion engine exhaust is directly released into the atmosphere, and carbon emissions cannot be absorbed within the system. The intake coupling method between SOFC and the internal combustion engine is singular, and the intake response lag problem is prominent under transient conditions of the internal combustion engine, making it difficult to improve turbo lag. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide an internal combustion engine-SOFC combined electric-heat-gas system. This system, through modules such as reversible SOFC / SOEC stacks, carbon dioxide capture, and turbine energy recovery, achieves energy coupling between the internal combustion engine and the solid oxide fuel cell, on-site carbon circulation, efficient utilization of exhaust waste heat, and improves the transient response speed of the internal combustion engine.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: In a first aspect, embodiments of the present invention provide an internal combustion engine-SOFC combined cycle power system, comprising: an internal combustion engine and a fuel cell; the fuel cell is configured with an electric combined cycle supercharging system, the electric combined cycle supercharging system having a battery compressor; the outlet of the battery compressor is connected to the inlet of the internal combustion engine; the anode outlet of the fuel cell is connected to the inlet of the internal combustion engine, and a steam-water separator and a syngas storage tank are sequentially arranged on the connecting pipeline; the outlet of the internal combustion engine is connected to the anode inlet of the fuel cell through two pipelines, one of which is equipped with a carbon dioxide capture device, and the other of which is equipped with a waste heat boiler.

[0007] In a further improved version, a fourth regulating valve and a third intercooler are provided on the connecting pipe between the battery compressor outlet and the internal combustion engine inlet; the electric compound supercharging system also includes a battery turbine and a motor, the motor is connected between the battery turbine and the battery compressor, the battery compressor is connected to the fuel cell inlet, the fuel cell outlet is connected to the battery turbine, and a catalytic combustor is provided on the connecting pipe.

[0008] In a further improved version, an intake preheater and a sixth regulating valve are installed on the connecting pipeline between the battery compressor and the fuel cell intake port, and a fifth regulating valve is connected in parallel on the pipelines at both ends of the intake preheater and the sixth regulating valve.

[0009] In a further improvement, the internal combustion engine is equipped with a turbocharging system, which includes an internal combustion engine turbine, an internal combustion engine compressor, and a connecting shaft. The connecting shaft connects the internal combustion engine compressor and the internal combustion engine turbine. The internal combustion engine compressor is connected to the internal combustion engine intake port, and a first intercooler is installed on the connecting pipe. The internal combustion engine outlet is connected to the internal combustion engine turbine.

[0010] In a further improved embodiment, the turbine outlet of the internal combustion engine is connected to the anode inlet of the fuel cell via the carbon dioxide capture device, and a first regulating valve is provided on the pipeline; the outlet of the internal combustion engine is connected to the anode inlet of the fuel cell via the waste heat boiler, and a bypass valve is provided before the waste heat boiler, and a seventh regulating valve is provided after the waste heat boiler.

[0011] In a further improved version, the internal combustion engine outlet is also connected to the internal combustion engine intake port, and an EGR valve and a second intercooler are installed on the connecting pipeline.

[0012] In a further improved version, a second regulating valve is provided between the syngas storage tank and the air inlet of the internal combustion engine, and the syngas storage tank is also connected to the anode inlet of the fuel cell, and a third regulating valve is provided on the connecting pipeline.

[0013] In a further improved version, the waste heat boiler is equipped with an electrolytic water supply pump, and an eighth regulating valve is also installed at the outlet of the waste heat boiler for external heat supply.

[0014] Secondly, embodiments of the present invention also provide a method for operating an internal combustion engine-SOFC combined heat and power system, the method comprising: Obtain the load rate of the internal combustion engine and the power surplus status of the system; When the internal combustion engine is under rated operating conditions, the fuel cell operates in SOFC mode. When the internal combustion engine is under low load and the system has surplus power, the fuel cell operates in SOEC mode, electrolyzing the carbon dioxide captured from the internal combustion engine exhaust with the high-temperature steam generated by the waste heat boiler into syngas. When dual fuel supply is required, the syngas in the syngas storage tank can be supplied to the fuel cell anode and the internal combustion engine intake at the same time; When a transient acceleration request from the internal combustion engine is detected, the motor of the electric compound supercharging system, powered by the fuel cell, drives the battery compressor to supplement the intake air into the internal combustion engine.

[0015] Thirdly, embodiments of the present invention also provide an application of an internal combustion engine-SOFC combined power supply system, which is applied to the combined power and electricity supply of ocean-going vessels, or to the combined power, heat and syngas supply of distributed energy stations, or to the combined power-heat-gas supply of integrated energy supply systems in industrial parks.

[0016] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: This system utilizes two separate pipelines connecting the internal combustion engine outlet to the fuel cell anode inlet, allowing the engine exhaust to supply either carbon dioxide or high-temperature steam. Combined with the fuel cell's switching between SOFC and SOEC modes, this enables the use of surplus electricity to electrolyze carbon dioxide and steam to generate syngas under low-load conditions, thus avoiding the problem of poor low-load energy efficiency. Secondly, the combination of the carbon dioxide capture device and the syngas storage tank allows carbon dioxide from the internal combustion engine exhaust to be captured and electrolyzed into syngas in SOEC mode. This syngas can then be used as fuel to supply either the internal combustion engine or the fuel cell, achieving on-site carbon emission recycling without the need for external carbon treatment. Thirdly, the battery compressor outlet is directly connected to the internal combustion engine inlet, allowing the fuel cell to power the electro-compound supercharging system during transient acceleration, supplementing the internal combustion engine with intake air from the battery compressor, overcoming the slow transient response problem caused by turbo lag. Finally, the fuel cell anode outlet, after passing through a steam-water separator and a syngas storage tank, is connected to the internal combustion engine inlet, allowing syngas to be supplied as a dual fuel, flexibly adjusting the load distribution between the two systems, and achieving optimal efficiency across all operating conditions. In summary, the carbon dioxide capture device and the waste heat boiler provide the raw materials required for electrolysis, the syngas storage tank serves as an intermediate buffer and fuel distribution node, and the electric compound supercharging system simultaneously serves the intake air supply of the fuel cell and the transient gas replenishment of the internal combustion engine. The entire system constitutes a reversible, adjustable, and multi-energy output coupled structure.

[0017] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0019] Figure 1 This is a schematic diagram of the system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the system in the first working mode provided in the embodiment of the present invention; Figure 3 This is a schematic diagram of the system in the second working mode provided in the embodiment of the present invention; Figure 4 This is a schematic diagram of the system in the third working mode provided in the embodiment of the present invention; In the diagram: 1. Fuel cell; 2. Internal combustion engine; 3. First intercooler; 4. Internal combustion engine compressor; 5. Connecting shaft; 6. Internal combustion engine turbine; 7. Carbon dioxide capture device; 8. First regulating valve; 9. EGR valve; 10. Bypass valve; 11. Second intercooler; 12. Third intercooler; 13. Second regulating valve; 14. Syngas storage tank; 15. Gas-liquid separator; 16. Third regulating valve; 17. Fourth regulating valve; 18. Fifth regulating valve; 19. Intake preheater; 20. Sixth regulating valve; 21. Battery compressor; 22. Motor; 23. Battery turbine; 24. Catalytic combustor; 25. Seventh regulating valve; 26. Waste heat boiler; 27. Electrolyzed water supply pump; 28. Eighth regulating valve; Detailed Implementation To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0020] Generally speaking, the terms "comprising" and "including" only indicate that the steps and elements are explicitly identified, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

[0021] Example 1 Terminology Explanation: SOFC: In this embodiment, it refers to a solid oxide fuel cell, which is used to directly convert the chemical energy of fuel into electrical energy.

[0022] SOEC: In this embodiment, it refers to a reversible solid oxide electrolytic cell, which is used to electrolyze water vapor and carbon dioxide into syngas under energized conditions.

[0023] EGR: In this embodiment, it refers to exhaust gas recirculation, which is used to return a portion of the exhaust gas from the internal combustion engine to the intake port of the internal combustion engine.

[0024] ICE: In this embodiment, it refers to the internal combustion engine, which provides mechanical power output to the system.

[0025] As described in the background section, existing SOFC-internal combustion engine composite systems have not achieved deep integration of reversible SOEC modes, and cannot simultaneously solve the core pain points of single system function, poor low-load energy efficiency, insufficient waste heat utilization, inability to absorb carbon emissions on-site, and weak adaptability to all operating conditions. There is an urgent need to develop a composite intake and exhaust system with reversible mode switching, on-site carbon cycle, multi-energy supply, and coordinated optimization under all operating conditions.

[0026] like Figure 1 As shown, in a typical embodiment of this disclosure, an internal combustion engine-SOFC combined cycle power system is provided. The system comprises an internal combustion engine 2 and a fuel cell 1. The fuel cell 1 is equipped with an electro-compound supercharging system, which includes a battery compressor 21. The outlet of the battery compressor 21 is connected to the inlet of the internal combustion engine 2, allowing the battery compressor 21 to directly supply compressed air or a gas-fuel mixture into the internal combustion engine 2. The anode outlet of the fuel cell 1 is connected to the inlet of the internal combustion engine 2, and a steam-water separator 15 and a syngas storage tank 14 are sequentially installed on the connecting pipeline. The outlet of the internal combustion engine 2 is connected to the anode inlet of the fuel cell 1 via two pipelines, one of which is equipped with a carbon dioxide capture device 7, and the other is equipped with a waste heat boiler 26.

[0027] The function of the gas-water separator 15 is to separate water vapor from the gas discharged from the anode of fuel cell 1. The remaining gas is mainly a mixture of carbon monoxide and hydrogen, i.e., syngas, which is stored in the syngas storage tank 14. The carbon dioxide capture device 7 is used to separate and collect carbon dioxide from the exhaust gas of internal combustion engine 2. The waste heat boiler 26 utilizes the high-temperature waste heat from the exhaust gas of internal combustion engine 2 to generate high-temperature steam. The above structure realizes three key pathways: first, the compressor of fuel cell 1 can directly supply gas to internal combustion engine 2; second, the syngas generated by the anode of fuel cell 1 can be supplied to internal combustion engine 2; third, the carbon dioxide in the exhaust gas of internal combustion engine 2 and the high-temperature steam generated by waste heat boiler 26 can be sent back to the anode inlet of fuel cell 1.

[0028] This system, by setting up two different pipelines from the outlet of the internal combustion engine 2 to the anode inlet of the fuel cell 1, allows the exhaust gas of the internal combustion engine 2 to provide either carbon dioxide or high-temperature steam. Combined with the switching between SOFC and SOEC modes of the fuel cell 1, it achieves the electrolysis of carbon dioxide and steam to generate syngas under low-load conditions using surplus electricity, thus avoiding the problem of poor energy efficiency at low loads. Secondly, the cooperation between the carbon dioxide capture device 7 and the syngas storage tank 14 allows the carbon dioxide in the exhaust gas of the internal combustion engine 2 to be captured and electrolyzed into syngas in SOEC mode. This syngas can then be used as fuel to supply either the internal combustion engine 2 or the fuel cell 1, achieving on-site carbon emission recycling without the need for external carbon treatment. Thirdly, the outlet of the battery compressor 21 is directly connected to the intake port of the internal combustion engine 2. This allows the fuel cell 1 to power the electric compound supercharging system during transient acceleration, with the battery compressor 21 supplementing the intake air to the internal combustion engine 2, overcoming the problem of slow transient response caused by the lag of the internal combustion engine turbine 6. Finally, the anode outlet of fuel cell 1 is connected to the air inlet of internal combustion engine 2 via gas-water separator 15 and syngas storage tank 14, so that syngas can be used as a dual fuel supply, flexibly adjusting the load distribution of the dual system and achieving optimal efficiency under all operating conditions.

[0029] The above features work together: the carbon dioxide capture device 7 and the waste heat boiler 26 provide the raw materials required for electrolysis, the syngas storage tank 14 serves as an intermediate buffer and fuel distribution node, and the electric compound supercharging system simultaneously serves the intake air supply of the fuel cell 1 and the transient gas replenishment of the internal combustion engine 2. The entire system constitutes a reversible, adjustable, multi-energy output coupled structure.

[0030] In some further specific examples of this disclosure, a fourth regulating valve 17 and a third intercooler 12 are provided on the connecting pipe between the outlet of the battery compressor 21 and the inlet of the internal combustion engine 2. The electric compound supercharging system also includes a battery turbine 23 and a motor 22, with the motor 22 connected between the battery turbine 23 and the battery compressor 21. The battery compressor 21 is connected to the inlet of the fuel cell 1, and the outlet of the fuel cell 1 is connected to the battery turbine 23, with a catalytic combustor 24 provided on the connecting pipe.

[0031] The fourth regulating valve 17 is used to control the flow rate and pressure of the gas supplied by the battery compressor 21 to the internal combustion engine 2. The third intercooler 12 is used to cool the compressed gas to prevent the intake temperature of the internal combustion engine 2 from becoming too high. The battery turbine 23, the motor 22, and the battery compressor 21 constitute an electro-compound supercharging unit: the unburned gas discharged from the outlet of the fuel cell 1 enters the catalytic combustor 24 and is burned under the action of the catalyst. The high-temperature gas generated drives the battery turbine 23 to do work, and the turbine drives the motor 22 to generate electricity or directly drive the battery compressor 21. The motor 22 can act as a generator 22 in SOFC mode to recover excess energy from the turbine, or it can act as a motor powered by the fuel cell 1 to drive the battery compressor 21 when auxiliary supercharging is required.

[0032] The electric-compound supercharging system can both recover exhaust energy and actively replenish air to the internal combustion engine 2, achieving synergy between energy recovery and active supercharging. The presence of the catalytic combustor 24 ensures that the gas entering the battery turbine 23 has sufficient temperature and flow rate, improving turbine efficiency. The intercooler avoids the adverse effects of high-temperature intake air on the charge coefficient and knocking of the internal combustion engine 2.

[0033] In some other specific examples of this disclosure, an intake preheater 19 and a sixth regulating valve 20 are provided on the connecting pipe between the battery compressor 21 and the intake port of the fuel cell 1, and a fifth regulating valve 18 is connected in parallel on the pipes at both ends of the intake preheater 19 and the sixth regulating valve 20.

[0034] The intake preheater 19 is used to preheat the air or mixture discharged from the battery compressor 21 to the operating temperature required by the fuel cell 1, typically using system waste heat or electric heating. The sixth regulating valve 20 controls the main gas flow rate into the fuel cell 1. The parallel fifth regulating valve 18 forms a bypass line; when preheating is not required or rapid flow regulation is needed, the fifth regulating valve 18 can be opened, allowing some or all of the gas to bypass the intake preheater 19 and directly enter the fuel cell 1.

[0035] This series-parallel structure allows for adjustable intake temperature of fuel cell 1, adapting to different starting, steady-state operation, and load variation requirements. For example, during cold start, the fifth regulating valve 18 is closed, and all gas is heated by the preheater; when a rapid increase in flow rate is required under high load, the fifth regulating valve 18 and the sixth regulating valve 20 can be opened simultaneously to increase the total intake volume, ensuring that fuel cell 1 can obtain suitable intake temperature and flow rate under any operating condition.

[0036] In some specific examples of this disclosure, the turbocharging system includes an internal combustion engine turbine 6, an internal combustion engine compressor 4, and a connecting shaft 5. The connecting shaft 5 connects the internal combustion engine compressor 4 and the internal combustion engine turbine 6. The internal combustion engine compressor 4 is connected to the intake port of the internal combustion engine 2, and a first intercooler 3 is provided on the connecting pipe. The outlet of the internal combustion engine 2 is connected to the internal combustion engine turbine 6.

[0037] The exhaust from internal combustion engine 2 drives the turbine 6 to rotate, which in turn drives the compressor 4 via connecting shaft 5. Fresh air is compressed, cooled by the first intercooler 3, and then sent into the intake port of internal combustion engine 2. Under normal operating conditions, internal combustion engine 2 relies on its own turbocharging to meet its intake requirements; during transient acceleration, the electric compound supercharging system can compensate for insufficient intake caused by turbo lag. The two systems are connected via a fourth regulating valve 17 and piping, allowing for parallel or series connection of the intake pathways. The first intercooler 3 reduces the intake temperature of internal combustion engine 2, improving charging density and anti-knock properties.

[0038] In some specific examples of this disclosure, the two pipelines from the outlet of the internal combustion engine turbine 6 to the anode inlet of the fuel cell 1 are as follows: the outlet of the internal combustion engine turbine 6 is connected to the anode inlet of the fuel cell 1 via a carbon dioxide capture device 7, and a first regulating valve 8 is provided on the pipeline; the outlet of the internal combustion engine 2 is connected to the anode inlet of the fuel cell 1 via a waste heat boiler 26, and a bypass valve 10 is provided before the waste heat boiler 26, and a seventh regulating valve 25 is provided after the waste heat boiler 26.

[0039] The first regulating valve 8 controls the flow rate of carbon dioxide gas from the outlet of the carbon dioxide capture device 7 to the anode of the fuel cell 1. The bypass valve 10 is located before the waste heat boiler 26. When it is not necessary to utilize exhaust waste heat to generate steam, the bypass valve 10 can be closed, allowing the exhaust gas to bypass the waste heat boiler 26. The seventh regulating valve 25 is located after the waste heat boiler 26 and is used to control the flow rate of high-temperature steam entering the anode of the fuel cell 1. The two lines can be controlled independently or opened simultaneously. In SOEC mode, both the first regulating valve 8 and the seventh regulating valve 25 are opened simultaneously, mixing carbon dioxide and high-temperature steam before sending it to the anode of the fuel cell 1 for electrolysis. In SOFC mode, only the first regulating valve 8 or only the seventh regulating valve 25 can be opened, depending on whether steam reforming is required. In some other specific examples of this disclosure, the outlet of the internal combustion engine 2 is also connected to the intake port of the internal combustion engine 2, and an EGR valve 9 and a second intercooler 11 are provided on the connecting pipeline, which constitutes an exhaust gas recirculation loop.

[0040] EGR valve 9 controls the amount of exhaust gas drawn back from the outlet of internal combustion engine 2 to the intake port. The second intercooler 11 is used to cool the recirculated exhaust gas, reducing its temperature to further suppress knocking in internal combustion engine 2 and reduce nitrogen oxide emissions. By adjusting the opening of EGR valve 9, some exhaust gas can be reintroduced into the cylinder, lowering the combustion temperature and reducing NOx formation. In syngas dual-fuel supply mode, because syngas contains hydrogen, the combustion speed is faster, easily producing higher combustion temperatures and NOx. In this case, EGR can effectively control emissions, allowing the system to meet emission requirements while improving efficiency.

[0041] In some specific examples of this disclosure, a second regulating valve 13 is provided between the syngas storage tank 14 and the air inlet of the internal combustion engine 2, and the syngas storage tank 14 is also connected to the anode inlet of the fuel cell 1, and a third regulating valve 16 is provided on the connecting pipeline.

[0042] The second regulating valve 13 controls the flow rate of syngas supplied from the syngas storage tank 14 to the internal combustion engine 2. The third regulating valve 16 controls the flow rate of syngas supplied from the syngas storage tank 14 to the anode of the fuel cell 1. These two regulating valves are controlled independently, allowing syngas to be distributed to the internal combustion engine 2, fuel cell 1, or supplied simultaneously as needed. In dual-fuel supply mode, the second regulating valve 13 and the third regulating valve 16 are opened simultaneously, supplying syngas to both the internal combustion engine 2 and fuel cell 1, allowing for flexible adjustment of the load distribution between the two systems. For example, when the load on the internal combustion engine 2 is low, more syngas can be allocated to the fuel cell 1 for power generation, and vice versa.

[0043] In some specific examples disclosed herein, the waste heat boiler 26 is equipped with an electrolytic water supply pump 27, and an eighth regulating valve 28 is also provided at the outlet of the waste heat boiler 26 for external heat supply.

[0044] Electrolytic water supply pump 27 supplies water required for electrolysis to waste heat boiler 26. Waste heat boiler 26 uses the waste heat from the exhaust of internal combustion engine 2 to heat the water into high-temperature steam. Part of the steam can be used for carbon dioxide electrolysis in SOEC mode, and the other part of the steam can be output externally through the eighth regulating valve 28 for heating. This enables the system to supply heat externally. In SOEC mode, the water supply flow rate of the water supply pump is matched with the carbon dioxide capture rate to ensure the stoichiometry of the electrolysis reaction. The opening degree of the eighth regulating valve 28 can be adjusted according to the external heat load demand to achieve combined heat and power supply. The system realizes combined electricity, heat, and gas supply, and when the system is connected to external green electricity, it can further achieve full life cycle carbon neutrality.

[0045] In summary, this invention features a reasonable design and simple structure. Through core modules such as a reversible SOFC / SOEC fuel cell stack, carbon dioxide capture, and turbine energy recovery, it achieves energy coupling and flexible mode switching between the internal combustion engine 2 and the solid oxide fuel cell stack. It boasts strong fuel adaptability and control flexibility, efficient utilization of exhaust waste heat, and internal carbon emission field circulation, improving the transient response speed of the internal combustion engine 2 and achieving optimal efficiency across all operating conditions. Furthermore, it realizes combined power, electricity, heat, and fuel supply, and combined with green electricity, it can achieve carbon neutrality throughout its entire life cycle, adapting to various scenarios such as distributed energy, marine propulsion, and industrial park power supply.

[0046] Example 2 This embodiment provides a working method for the internal combustion engine-SOFC combined heat and power system as described in Embodiment 1: Obtain the load rate of internal combustion engine 2 and the power surplus status of the system.

[0047] When the internal combustion engine 2 is under rated operating conditions, the fuel cell 1 is operated in SOFC mode.

[0048] When the internal combustion engine 2 is under low load and the system has surplus power, the fuel cell 1 is operated in SOEC mode, and the carbon dioxide captured by the exhaust of the internal combustion engine 2 is electrolyzed with the high-temperature steam generated by the waste heat boiler 26 to form syngas.

[0049] When dual fuel supply is required, the syngas in the syngas storage tank 14 is supplied to the anode of the fuel cell 1 and the air inlet of the internal combustion engine 2 simultaneously.

[0050] When a transient acceleration request from the internal combustion engine 2 is detected, the motor 22 of the electric compound supercharging system, powered by the fuel cell 1, drives the battery compressor 21 to supplement the intake air into the internal combustion engine 2.

[0051] This method switches between four modes based on the internal combustion engine load rate and the state of power surplus: Open the sixth regulating valve 20 and close the EGR valve 9, bypass valve 10, second regulating valve 13, third regulating valve 16, fourth regulating valve 17, fifth regulating valve 18, seventh regulating valve 25 and eighth regulating valve 28 to enable the fuel cell 1 to operate in SOFC mode. The fuel cell 1 generates electricity efficiently, the internal combustion engine 2 outputs mechanical power, and the turbine recovers exhaust energy.

[0052] When the internal combustion engine 2 is under low load and the system has excess power, such as Figure 2 As shown, the first regulating valve 8, the fifth regulating valve 18, the seventh regulating valve 25 and the second regulating valve 13 are opened, and the EGR valve 9, the bypass valve 10, the fourth regulating valve 17, the sixth regulating valve 20 and the eighth regulating valve 28 are closed, entering the SOEC electrolysis-on-site carbon cycle mode, utilizing the system's surplus electrical energy / green electricity; the carbon dioxide captured by the ICE exhaust and the high-temperature steam generated by the waste heat boiler 26 are electrolyzed into syngas, realizing on-site carbon emission cycle and combined power generation, heating and gas supply.

[0053] like Figure 3 As shown, EGR valve 9, second regulating valve 13, third regulating valve 16, and sixth regulating valve 20 are opened, while bypass valve 10, fourth regulating valve 17, fifth regulating valve 18, seventh regulating valve 25, and eighth regulating valve 28 are closed, entering the syngas dual-fuel supply mode. Syngas simultaneously supplies gas to both SOFC and ICE, flexibly adjusting the load distribution of the two systems to achieve optimal efficiency under all operating conditions, while reducing 2NO in the internal combustion engine. x emission, like Figure 4 As shown, open EGR valve 9, fourth regulating valve 17 and sixth regulating valve 20, and close bypass valve 10, second regulating valve 13, third regulating valve 16, fifth regulating valve 18, seventh regulating valve 25 and eighth regulating valve 28 to enter SOFC electric auxiliary boost-ICE transient response mode. SOFC power assists boost, supplements ICE intake, solves ICE turbo lag, and greatly improves transient response speed.

[0054] The above method is automatically executed by detecting load factor and power surplus status, requiring no manual intervention. All valve openings, motor output power, and fuel cell stack operating modes can be optimized and adjusted in real time to meet the flow, pressure, and power requirements of the dual systems under all operating conditions, achieving optimal overall system energy efficiency. This method achieves optimal efficiency under all operating conditions, solving problems such as poor energy efficiency at low loads, inability to absorb carbon emissions on-site, and slow transient response.

[0055] Example 3 This embodiment provides an application of the internal combustion engine-SOFC combined cycle power system as described in Embodiment 1: The system described is applied to the combined power and electricity supply of ocean-going vessels, or to the combined power, heat and syngas supply of distributed energy stations, or to the combined power-heat-gas supply of integrated energy supply systems in industrial parks.

[0056] In the context of ocean-going vessels, the system can provide the mechanical power required for propulsion and onboard electricity, while utilizing the ship's space to house syngas storage tanks 14 and carbon dioxide capture devices 7, achieving low-carbon ship propulsion. In the context of distributed energy stations, the system can provide electricity, heating or industrial heat, and syngas to surrounding users. In the context of integrated energy supply in industrial parks, the system can simultaneously meet the park's electricity, heating, and gas needs, and utilize potentially inexpensive green electricity within the park for SOEC electrolysis, achieving carbon cycling for the park.

[0057] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An internal combustion engine-SOFC combined cycle power system, characterized in that, include: An internal combustion engine and a fuel cell; the fuel cell is equipped with an electric compound supercharging system, the electric compound supercharging system having a battery compressor; The outlet of the battery compressor is connected to the air inlet of the internal combustion engine. The anode outlet of the fuel cell is connected to the air inlet of the internal combustion engine, and a steam-water separator and a syngas storage tank are sequentially installed on the connecting pipeline. The internal combustion engine outlet and the fuel cell anode inlet are connected by two pipelines, one of which is equipped with a carbon dioxide capture device and the other is equipped with a waste heat boiler.

2. The internal combustion engine-SOFC combined cycle power system as described in claim 1, characterized in that, A fourth regulating valve and a third intercooler are installed on the connecting pipe between the battery compressor outlet and the internal combustion engine inlet; the electric compound supercharging system also includes a battery turbine and a motor, the motor is connected between the battery turbine and the battery compressor, the battery compressor is connected to the fuel cell inlet, the fuel cell outlet is connected to the battery turbine, and a catalytic combustor is installed on the connecting pipe.

3. The internal combustion engine-SOFC combined cycle power system as described in claim 2, characterized in that, An intake preheater and a sixth regulating valve are installed on the connecting pipeline between the battery compressor and the fuel cell intake port. A fifth regulating valve is connected in parallel on the pipelines at both ends of the intake preheater and the sixth regulating valve.

4. The internal combustion engine-SOFC combined cycle power system as described in claim 1, characterized in that, The internal combustion engine is equipped with a turbocharging system, which includes an internal combustion engine turbine, an internal combustion engine compressor, and a connecting shaft. The connecting shaft connects the internal combustion engine compressor and the internal combustion engine turbine. The internal combustion engine compressor is connected to the internal combustion engine intake port, and a first intercooler is installed on the connecting pipe. The internal combustion engine outlet is connected to the internal combustion engine turbine.

5. The internal combustion engine-SOFC combined cycle power system as described in claim 4, characterized in that, The turbine outlet of the internal combustion engine is connected to the anode inlet of the fuel cell via the carbon dioxide capture device, and a first regulating valve is provided on the pipeline; the outlet of the internal combustion engine is connected to the anode inlet of the fuel cell via the waste heat boiler, and a bypass valve is provided before the waste heat boiler and a seventh regulating valve is provided after the waste heat boiler.

6. The internal combustion engine-SOFC combined cycle power system as described in claim 1, characterized in that, The internal combustion engine outlet is also connected to the internal combustion engine intake, and an EGR valve and a second intercooler are installed on the connecting pipeline.

7. The internal combustion engine-SOFC combined cycle power system as described in claim 1, characterized in that, A second regulating valve is provided between the syngas storage tank and the air inlet of the internal combustion engine. The syngas storage tank is also connected to the anode inlet of the fuel cell, and a third regulating valve is provided on the connecting pipeline.

8. The internal combustion engine-SOFC combined cycle power system as described in claim 1, characterized in that, The waste heat boiler is equipped with an electrolytic water supply pump, and an eighth regulating valve is also installed at the outlet of the waste heat boiler for external heat supply.

9. A method for operating an internal combustion engine-SOFC combined heat and power system as described in any one of claims 1-8, characterized in that, The method includes: Obtain the load rate of the internal combustion engine and the power surplus status of the system; When the internal combustion engine is under rated operating conditions, the fuel cell operates in SOFC mode. When the internal combustion engine is under low load and the system has surplus power, the fuel cell operates in SOEC mode, electrolyzing the carbon dioxide captured from the internal combustion engine exhaust with the high-temperature steam generated by the waste heat boiler into syngas. When dual fuel supply is required, the syngas in the syngas storage tank can be supplied to the fuel cell anode and the internal combustion engine intake at the same time; When a transient acceleration request from the internal combustion engine is detected, the motor of the electric compound supercharging system, powered by the fuel cell, drives the battery compressor to supplement the intake air into the internal combustion engine.

10. An application of the internal combustion engine-SOFC combined cycle power system as described in any one of claims 1-8, characterized in that, The system can be applied to the combined power and electricity supply of ocean-going vessels, or to the combined power, heat and syngas supply of distributed energy stations, or to the combined power-heat-gas supply of integrated energy supply systems in industrial parks.

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