Multi-energy complementary system based on solid oxide fuel cell

Abstract

The utility model relates to the technical field of solid oxide fuel cells, and discloses a multi-energy complementary system based on a solid oxide fuel cell, the system comprises a fuel module, an SOFC power generation device, a heat utilization system and an electric regulation and control system, the heat utilization system comprises a gas turbine, a heat storage system and a heat pump system, the heat storage system is a single-tank heat storage system or a double-tank heat storage system, and the double-tank heat storage system comprises a first heat storage tank body, a first heat exchanger communicated with a hot working medium inlet and outlet of the first heat storage tank body, a second heat storage tank body and a second heat exchanger communicated with a heat-conducting medium inlet of the second heat storage tank body. The electricity utilization system comprises an electric energy storage system and an electric power conversion module which are connected with the electric energy output end of the SOFC power generation device. According to the system, the SOFC and multiple energy technologies are cooperated, the SOFC high-temperature exhaust can drive the gas turbine to generate power, heat supply or refrigeration is conducted through the heat pump system, and efficient utilization of energy is achieved.

Description

Multi-energy complementary system based on solid oxide fuel cell Technical Field

[0001] This invention belongs to the field of solid oxide fuel cell technology, and specifically relates to a multi-energy complementary system based on solid oxide fuel cells. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are considered a core technology for achieving energy cascade utilization due to their wide fuel adaptability (directly using hydrogen, natural gas, biogas, etc.), high waste heat quality (600-1000℃), and strong stability of their all-solid-state structure. SOFCs use solid oxides as the electrolyte and achieve electrochemical reactions through oxygen ion conduction. Their typical operating temperature is 600-1000℃, significantly higher than proton exchange membrane fuel cells (PEMFCs), bringing two core advantages: first, fuel flexibility: the high-temperature environment allows hydrocarbon fuels such as methane to be directly utilized through internal reforming without additional purification equipment; second, efficient combined heat and power (CHP): high-temperature exhaust gas can drive a gas turbine, achieving a total system efficiency of over 85%. However, single SOFC systems suffer from slow cold start-up, insufficient dynamic response, and the need to optimize thermoelectric coupling efficiency, necessitating multi-energy complementary integration to improve overall performance. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a multi-energy complementary system based on solid oxide fuel cells (SOFCs). By coordinating SOFCs with multiple energy technologies, the high-temperature exhaust gas from the SOFC can drive a gas turbine to generate electricity and provide heating or cooling through a heat pump system, thereby increasing the overall system efficiency to 85%–95%. This achieves highly efficient energy utilization.

[0004] To achieve the goal of efficient utilization of the aforementioned energy, the present invention provides the following technical solution:

[0005] A multi-energy complementary system based on a solid oxide fuel cell (SOFC) includes: a fuel module and an SOFC power generation device, wherein the outlet of the fuel module is connected to the fuel inlet of the SOFC power generation device; the multi-energy complementary system further includes: a thermal utilization system and an electrical control system, wherein the thermal utilization system is connected to the anode gas outlet of the SOFC power generation device, and the electrical utilization system is connected to the power output terminal of the SOFC power generation device.

[0006] Furthermore, the fuel module includes a filter and a dryer, wherein the inlet of the filter is connected to a fuel gas pipeline and the outlet is connected to the inlet of the dryer;

[0007] The fuel module further includes a desulfurization device, the fuel inlet of which is connected to the fuel outlet of the drying device, and the fuel outlet of the desulfurization device is connected to the anode fuel inlet of the SOFC power generation unit, with a fourth valve provided between the two.

[0008] Furthermore, the fuel module also includes: a reforming reactor, the fuel inlet of which is connected to the fuel outlet of the desulfurization unit, and a second valve is provided between the fuel inlet of the reforming reactor and the fuel outlet of the desulfurization unit; the fuel outlet of the reforming reactor is connected to the anode fuel inlet of the SOFC power generation unit, and a third valve is provided between the two.

[0009] Furthermore, the heat utilization system includes: a gas turbine and a thermal storage system, wherein the gas turbine inlet is connected to the anode gas outlet of the SOFC power generation unit, and the thermal storage system is connected to the exhaust gas outlet of the gas turbine;

[0010] The heat utilization system further includes a heat pump system, wherein the heat pump system's working fluid inlet is connected to the heat storage system's working fluid outlet, and the heat pump system's working fluid outlet is connected to the heat storage system's working fluid inlet.

[0011] Furthermore, the thermal storage system is a single-tank thermal storage system, including: a thermal storage tank, and a first heat exchanger and a second heat exchanger connected to the thermal working medium of the thermal storage tank. The exhaust inlet of the first heat exchanger is connected to the exhaust outlet of the gas turbine, the heat exchange medium outlet of the first heat exchanger is connected to the heat exchange medium inlet of the thermal storage tank, and the heat transfer medium inlet of the second heat exchanger is connected to the heat transfer medium outlet of the thermal storage tank.

[0012] Furthermore, the thermal storage system is a dual-tank thermal storage system, comprising: a first thermal storage tank, and a first heat exchanger connected to the thermal working medium inlet and outlet of the first thermal storage tank, wherein the exhaust inlet of the first heat exchanger is connected to the exhaust outlet of the gas turbine, and the heat exchange medium outlet of the first heat exchanger is connected to the heat exchange medium inlet of the first thermal storage tank.

[0013] The dual-tank thermal storage system further includes: a second thermal storage tank, and a second heat exchanger connected to the thermal medium inlet of the second thermal storage tank, wherein the thermal medium inlet of the second heat exchanger is connected to the thermal medium outlet of the first thermal storage tank.

[0014] Furthermore, the first heat storage tank is cylindrical with a height-to-diameter ratio of 1:1 to 2:1, and is covered with a nitrogen gas layer on top. The first heat storage tank is equipped with a pressure control valve.

[0015] Furthermore, the second heat storage tank has a flat bottom design, is equipped with an agitator, and has an inclined bottom with a slope of 2 to 5 degrees.

[0016] Furthermore, the electricity utilization system includes: an energy storage system and a power conversion module connected to the energy output terminal of the SOFC power generation device; the energy output terminal of the SOFC power generation device is connected to the energy input terminal of the heat pump system; the energy storage system is connected to the energy input terminal of the heat pump system; the energy storage system is connected to the power conversion module; and power switches are provided between the energy output terminal of the SOFC power generation device, the energy storage system, the power conversion module, and the energy input terminal of the heat pump system.

[0017] Furthermore, the energy storage system is a supercapacitor system.

[0018] Compared with existing technologies, the present invention provides a multi-energy complementary system based on a solid oxide fuel cell, which has the following advantages:

[0019] Firstly, efficiency is improved; SOFC waste heat drives gas turbine power generation, and the overall system efficiency can exceed 90%.

[0020] Second, dynamic response: supercapacitors compensate for the minute-level power regulation delay of SOFC, meeting the second-level load fluctuation requirements.

[0021] Thirdly, it features fuel synergy, with a dual gas source design for hydrogen production via water electrolysis and hydrocarbon fuels to ensure energy security under extreme weather conditions.

[0022] Fourth, it uses heat-electricity coordinated scheduling for peak-valley regulation, storing SOFC waste heat during off-peak hours and releasing heat during peak hours to drive steam turbines for power generation. Attached Figure Description

[0023] Figure 1 is a structural diagram of a multi-energy complementary system based on a solid oxide fuel cell;

[0024] Figure 2 shows the optimized structure of a multi-energy complementary system based on a solid oxide fuel cell.

[0025] In the diagram: 1. Filtration device; 2. Drying device; 3. Desulfurization device; 3-1. Fourth valve; 4. Reforming reactor; 4-1. Second valve; 4-2. Third valve; 5. Electrolytic water hydrogen production device; 5-1. First valve; 6. SOFC power generation device; 7. Gas turbine; 8. Power conversion module; 9. Energy storage system; 10. First heat exchanger; 11. Second heat exchanger; 12. Thermal storage tank; 12-1. First thermal storage tank; 12-2. Second thermal storage tank; 13. Heat pump system. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] A multi-energy complementary system based on a solid oxide fuel cell (SOFC) includes: a fuel module and an SOFC power generation unit 6, wherein the outlet of the fuel module is connected to the fuel inlet of the SOFC power generation unit 6; the multi-energy complementary system based on the SOFC also includes: a thermal utilization system and an electrical control system, wherein the thermal utilization system is connected to the anode gas outlet of the SOFC power generation unit 6, and the electrical utilization system is connected to the power output terminal of the SOFC power generation unit 6. The fuel module is used to improve the fuel flexibility of the SOFC power generation unit 6, allowing carbon-based fuels such as natural gas and biogas to avoid hydrogen purification costs through internal reforming; the thermal utilization system enables efficient cascade utilization of waste heat from the SOFC power generation unit 6, with a comprehensive energy efficiency exceeding 85%; the electrical control system enables flexible energy dispatch.

[0028] In a preferred embodiment, the fuel module includes: an electrolytic water hydrogen production device 5 and a first valve 5-1. The hydrogen outlet of the electrolytic water hydrogen production device 5 is connected to the anode of the SOFC power generation device, and the first valve 5-1 is provided between the hydrogen outlet of the electrolytic water hydrogen production device 5 and the anode of the SOFC power generation device for controlling the input of hydrogen produced by the electrolytic water hydrogen production device to the anode of the SOFC power generation device.

[0029] In a preferred embodiment, the fuel module includes a filter device 1 and a dryer device 2. The inlet of the filter device 1 is connected to a fuel gas pipeline, and the outlet is connected to the inlet of the dryer device 2. The filter device 1 and the dryer device 2 are used to remove fuel gas particles, moisture and impurities to prevent fuel gas containing impurities from clogging the microchannels of the SOFC power generation unit 6 stack.

[0030] The fuel module further includes: a desulfurization unit 3 and a reforming reactor 4. The fuel inlet of the desulfurization unit 3 is connected to the fuel outlet of the drying unit 2 to remove sulfides from the fuel and prevent sulfur poisoning of the SOFC power generation unit 6, which would lead to catalyst deactivation. The fuel inlet of the reforming reactor 4 is connected to the fuel outlet of the desulfurization unit 3, and a second valve 4-1 is provided between the fuel inlet of the reforming reactor 4 and the fuel outlet of the desulfurization unit 3. The fuel outlet of the reforming reactor 4 is connected to the anode fuel inlet of the SOFC power generation unit 6, and a third valve 4-2 is provided between the two. The fuel outlet of the desulfurization unit 3 is connected to the anode fuel inlet of the SOFC power generation unit 6, and a fourth valve 3-1 is provided between the two. The reforming reactor 4 converts hydrocarbon fuel into syngas rich in H2 and CO.

[0031] The fuel module of SOFC power generation unit 6 is a core subsystem of its multi-energy complementary system. During operation, the fuel supply to SOFC power generation unit 6 is diversified by opening and closing the first valve 5-1, the second valve 4-1, the third valve 4-2, and the fourth valve 3-1. When hydrogen fuel is supplied to SOFC power generation unit 6, the second valve 4-1, the third valve 4-2, and the fourth valve 3-1 are closed, and the first valve 5-1 is opened. When hydrocarbon fuel is supplied to SOFC power generation unit 6, the first valve 5-1, the second valve 4-1, the third valve 4-2 are closed, and the fourth valve 3-1 is opened. When syngas rich in H2 and CO is supplied to SOFC power generation unit 6, the first valve 5-1, the fourth valve 3-1 are closed, and the second valve 4-1 and the third valve 4-2 are opened. The fuel module converts the original hydrocarbon fuel into high-purity fuel gas suitable for stack operation, while optimizing thermodynamic conditions and avoiding stack poisoning or carbon buildup.

[0032] As a preferred embodiment, the multi-energy complementary system thermal utilization system based on solid oxide fuel cells includes: a gas turbine 7, the inlet of which is connected to the anode gas outlet of the SOFC power generation unit 6. The SOFC power generation unit operates at high temperature (700–1000°C) and directly converts the chemical energy of fuel (natural gas, hydrogen, etc.) into electrical energy. The gas turbine 7 is driven by the high-temperature exhaust gas (600–900°C) of the SOFC power generation unit to further generate electricity or perform mechanical work, thereby improving the overall efficiency.

[0033] As a preferred embodiment, the multi-energy complementary system thermal utilization system based on solid oxide fuel cells further includes a thermal storage system, which is connected to the exhaust gas outlet of the gas turbine 7 and is used to store the thermal energy of the exhaust gas from the gas turbine 7, so as to improve energy utilization efficiency, balance supply and demand fluctuations and enhance system flexibility.

[0034] Preferably, the thermal storage system is a single-tank thermal storage system, including: a thermal storage tank 12, and a first heat exchanger 10 and a second heat exchanger 11 connected to the thermal working medium inlet and outlet of the thermal storage tank. The thermal storage tank 12 saves space by temperature stratification (hot medium on top, cold medium on the bottom).

[0035] The exhaust inlet of the first heat exchanger 10 is connected to the exhaust outlet of the gas turbine 7, and the heat exchange medium outlet of the first heat exchanger 10 is connected to the heat exchange medium inlet of the heat storage tank 12, thereby storing the heat from the exhaust of the gas turbine 7 in the heat storage tank 12. The heat transfer medium inlet of the second heat exchanger 11 is connected to the heat transfer medium outlet of the heat storage tank 12, and is used to export the heat energy stored in the heat storage tank 12 to form low-grade heat energy for the use of heat energy demanders.

[0036] Preferably, the heat storage system is a dual-tank heat storage system, including: a first heat storage tank 12-1, and a first heat exchanger 10 connected to the heat medium inlet and outlet of the first heat storage tank 12-1. The exhaust inlet of the first heat exchanger 10 is connected to the exhaust outlet of the gas turbine 7, and the heat exchange medium outlet of the first heat exchanger 10 is connected to the heat exchange medium inlet of the first heat storage tank 12-1, thereby realizing the storage of heat from the exhaust of the gas turbine 7 in the first heat storage tank 12-1.

[0037] The dual-tank thermal storage system further includes: a second thermal storage tank 12-2, and a second heat exchanger 11 connected to the inlet of the heat transfer medium of the second thermal storage tank 12-2. The inlet of the heat transfer medium of the second heat exchanger 11 is connected to the outlet of the heat transfer medium of the first thermal storage tank 12-1, and is used to export the high-grade thermal energy stored in the first thermal storage tank 12-1 to form low-grade thermal energy, which is stored in the second thermal storage tank 12-2 for use by the thermal energy demander.

[0038] The first thermal storage tank 12-1 is cylindrical with a height-to-diameter ratio of 1:1 to 2:1. A nitrogen-covered top layer prevents molten salt oxidation. It also features a pressure control valve to maintain a slight positive pressure (<0.5 bar). The first thermal storage tank 12-1 stores high-grade heat energy from gas turbine exhaust, using high-temperature molten salt or heat transfer oil as the storage medium. It is constructed from high-temperature resistant materials and has an internal insulated floating roof to reduce heat loss. The second thermal storage tank 12-2 has a flat bottom and is equipped with an agitator to prevent salt crystallization and precipitation. Its bottom is sloped at 2-5° and includes a slag discharge port for regular cleaning. The second thermal storage tank 12-2 stores low-grade heat energy generated through heat exchange in a second heat exchanger. It has a simpler structure, typically using ordinary stainless steel, and includes a slag discharge port and a stirring device at the bottom to prevent medium crystallization.

[0039] In a preferred embodiment, the multi-energy complementary system based on a solid oxide fuel cell further includes a heat pump system 13. The heat pump system's working fluid inlet is connected to the heat storage system's working fluid outlet, and the heat pump system 13's working fluid outlet is connected to the heat storage system's working fluid inlet. The heat pump system 13 uses gas as the working fluid and transfers heat from a low-temperature environment to a high-temperature environment by consuming a small amount of electrical or mechanical energy, thereby achieving functions such as heating, cooling, and hot water supply. Its core function is to improve energy utilization efficiency, reduce carbon emissions, and adapt to energy needs in multiple scenarios.

[0040] In a preferred embodiment, the electricity utilization system includes: an energy storage system 9 and a power conversion module 8 connected to the energy output terminal of the SOFC power generation device 6. The energy output terminal of the SOFC power generation device 6 is connected to the energy input terminal of the heat pump system 13. The energy storage system 9 is connected to the energy input terminal of the heat pump system 13. The energy storage system 9 is connected to the power conversion module 8. Power switches are provided between the energy output terminal of the SOFC power generation device 6, the energy storage system 9, the power conversion module 8, and the energy input terminal of the heat pump system 13 to control the opening and closing of the circuits between them under different operating conditions.

[0041] Preferably, the energy storage system 9 is a supercapacitor system.

[0042] When a multi-energy complementary system based on solid oxide fuel cells faces different application scenarios, it can achieve different applications through thermal-electric coordinated scheduling and peak-valley regulation.

[0043] 1. Main scenarios for winter heating

[0044] The energy flow of the entire system is as follows: the high-temperature waste heat from SOFC power generation unit 6 is introduced into the thermal storage system. The thermal storage system directly or through a heat pump heating mode provides 60°C hot water to the district. The control logic is as follows: During peak electricity prices in the daytime: SOFC power generation unit 6 operates at full load, the thermal storage system is charged, and the heat pump uses waste heat for direct heating. During off-peak electricity prices at night: SOFC power generation unit 6 reduces its load to 40%, and the heat pump system 13 switches to grid-powered thermal storage.

[0045] 2. Summer cooling as the primary scenario

[0046] The energy flow of the entire system is as follows: the low-temperature waste heat from the SOFC power generation unit 6 enters the heat pump system 13, thereby outputting cooling capacity and providing 7°C chilled water. The control logic is as follows: during high-temperature periods: the waste heat from the SOFC power generation unit 6 prioritizes driving the heat pump system 13 for cooling, while the thermal storage system assists in balancing the fluctuations in cooling load.

[0047] 3. Electricity demand fluctuation scenarios

[0048] The thermal storage system is used to smooth out power fluctuations of SOFC power generation unit 6, and the heat pump system 13 stores heat during periods of low electricity prices and releases heat during periods of high prices, thereby reducing dependence on the power grid.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-energy complementary system based on a solid oxide fuel cell, characterized in that: The multi-energy complementary system includes: a fuel module and an SOFC power generation device (6), wherein the outlet of the fuel module is connected to the fuel inlet of the SOFC power generation device (6); the multi-energy complementary system also includes: a heat utilization system and an electrical control system, wherein the heat utilization system is connected to the anode gas outlet of the SOFC power generation device (6), and the electrical utilization system is connected to the power output terminal of the SOFC power generation device (6).

2. The multi-energy complementary system based on a solid oxide fuel cell according to claim 1, characterized in that: The fuel module includes a filter (1) and a dryer (2). The filter (1) is connected to a fuel gas pipeline at its inlet and its outlet is connected to the inlet of the dryer (2). The fuel module also includes a desulfurization device (3). The fuel inlet of the desulfurization device (3) is connected to the fuel outlet of the dryer (2), and the fuel outlet of the desulfurization device (3) is connected to the anode fuel inlet of the SOFC power generation unit (6). A fourth valve (3-1) is provided between the two.

3. The multi-energy complementary system based on a solid oxide fuel cell according to claim 2, characterized in that: The fuel module further includes: a reforming reactor (4), the fuel inlet of the reforming reactor (4) is connected to the fuel outlet of the desulfurization device (3), and a second valve (4-1) is provided between the fuel inlet of the reforming reactor (4) and the fuel outlet of the desulfurization device (3), and a third valve (4-2) is provided between the two.

4. The multi-energy complementary system based on a solid oxide fuel cell according to claim 1, characterized in that: The heat utilization system includes a gas turbine (7) and a thermal storage system. The inlet of the gas turbine (7) is connected to the anode gas outlet of the SOFC power generation unit (6), and the thermal storage system is connected to the exhaust gas outlet of the gas turbine (7). The heat utilization system also includes a heat pump system (13). The inlet of the heat pump system (13) is connected to the outlet of the thermal storage system, and the outlet of the heat pump system (13) is connected to the inlet of the thermal storage system.

5. The multi-energy complementary system based on a solid oxide fuel cell according to claim 4, characterized in that: The heat storage system is a single-tank heat storage system, including: a heat storage tank (12), and a first heat exchanger (10) and a second heat exchanger (11) connected to the heat working medium inlet of the heat storage tank. The exhaust inlet of the first heat exchanger (10) is connected to the exhaust outlet of the gas turbine (7), the heat exchange medium outlet of the first heat exchanger (10) is connected to the heat exchange medium inlet of the heat storage tank (12), and the heat transfer medium inlet of the second heat exchanger (11) is connected to the heat transfer medium outlet of the heat storage tank (12).

6. The multi-energy complementary system based on a solid oxide fuel cell according to claim 4, characterized in that: The thermal storage system is a dual-tank thermal storage system, including: a first thermal storage tank (12-1) and a first heat exchanger (10) connected to the inlet and outlet of the working medium of the first thermal storage tank (12-1). The exhaust inlet of the first heat exchanger (10) is connected to the exhaust outlet of the gas turbine (7), and the heat exchange medium outlet of the first heat exchanger (10) is connected to the heat exchange medium inlet of the first thermal storage tank (12-1). The dual-tank thermal storage system also includes: a second thermal storage tank (12-2) and a second heat exchanger (11) connected to the heat transfer medium inlet of the second thermal storage tank (12-2). The heat transfer medium inlet of the second heat exchanger (11) is connected to the heat transfer medium outlet of the first thermal storage tank (12-1).

7. The multi-energy complementary system based on a solid oxide fuel cell according to claim 6, characterized in that: The first heat storage tank (12-1) is cylindrical with a height-to-diameter ratio of 1:1 to 2:

1. A nitrogen covering layer is provided on the top. The first heat storage tank (12-1) is equipped with a pressure control valve.

8. The multi-energy complementary system based on a solid oxide fuel cell according to claim 6, characterized in that: The second heat storage tank (12-2) has a flat bottom design, is equipped with an agitator, and has an inclined bottom with a slope of 2 to 5 degrees.

9. The multi-energy complementary system based on a solid oxide fuel cell according to claim 4, characterized in that: The electricity utilization system includes: an energy storage system (9) and a power conversion module (8) connected to the power output terminal of the SOFC power generation device (6). The power output terminal of the SOFC power generation device (6) is connected to the power input terminal of the heat pump system (13). The energy storage system (9) is connected to the power input terminal of the heat pump system (13). The energy storage system (9) is connected to the power conversion module (8). Power switches are provided between the power output terminal of the SOFC power generation device (6), the energy storage system (9), the power conversion module (8), and the power input terminal of the heat pump system (13).

10. The multi-energy complementary system based on a solid oxide fuel cell according to claim 9, characterized in that: The energy storage system (9) is a supercapacitor system.

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