Combined power supply system and method based on heat engine and solid oxide fuel cell

Abstract

Disclosed in the present invention is a combined power supply system based on a heat engine and a solid oxide fuel cell, comprising a gas turbine generator module, a heat exchange module, and a fuel cell supply module. The gas turbine generator module is coupled with the heat exchange module by means of a turbine; the turbine performs work to generate power for primary power generation, and is connected to the heat exchange module to heat air; the heat exchange module is connected to the fuel cell supply module to output the heated air to a cathode of the solid oxide fuel cell of the fuel cell supply module; a basic hydrocarbon fuel is input into an anode of the solid oxide fuel cell by means of a pipe; an output end of the solid oxide fuel cell is connected to a combustion chamber to perform oxygen-deficient combustion for power generation; and by connecting the turbine, a product which fails to be sufficiently combusted is re-combusted to perform work. The present invention promotes the transformation and upgrading of fossil fuel power plants, avoids resource waste, further improves the power generation efficiency, and is more energy-saving and environmentally-friendly.

Description

A combined power supply system and method based on heat engine and solid oxide fuel cell Technical Field

[0001] The present invention belongs to the field of composite power generation, and in particular relates to a power supply system and method based on a combination of a heat engine and a solid oxide fuel cell. Background Art

[0002] To achieve carbon peak and carbon neutrality, accelerate the development of a new energy system, and implement the national "dual carbon" strategy, my country is steadily advancing its renewable energy power generation efforts. According to statistics, by the end of 2022, China's total installed power generation capacity reached 2.56 billion kilowatts, of which thermal power accounted for 52% and renewable energy power generation accounted for 48%. Of this, wind and photovoltaic power generation accounted for 760 million kilowatts, or 30% of the total installed capacity, and generated 1.2 trillion kilowatt-hours, or 14% of the total power generation. However, the development of non-fossil energy power generation faces numerous challenges. Wind power generation is affected by environmental factors such as weather, season, terrain, and installation location, resulting in unstable power generation and requiring large land areas. Photovoltaic power generation suffers from low energy density and low power conversion efficiency, and lacks continuity due to lack of sunlight at night. Hydropower generation is extremely expensive and has ecological impacts due to changes in the landscape. Nuclear power generation produces radioactive waste, and accidents can have severe, irreversible, and long-term impacts on the environment and society. Furthermore, fossil fuel power generation is gradually being phased out, leading to social problems such as power plant closures and worker layoffs. Therefore, promoting the transformation and upgrading of fossil fuel power plants is a highly reliable solution.

[0003] In recent years, fuel cell power generation technology has attracted widespread attention due to its high power generation efficiency, low environmental pollution, high specific energy, low noise, and wide fuel range. However, current fuel cell technology is constrained by technical bottlenecks, making it difficult to fully utilize the energy in the fuel. Unused residual fuel still exists in the anode exhaust, and the cathode and anode exhaust temperatures of the battery are relatively high. Direct discharge will lead to serious heat waste and thermal pollution. Therefore, before solid oxide fuel cells can achieve clean power generation, there is an urgent need to solve technical problems such as how to fully utilize the unreacted fuel in the battery and recover high-grade waste heat.

[0004] Combining this with existing thermal engine power generation technology to create a hybrid power generation system would not only further improve power generation efficiency but also promote the transformation and upgrading of traditional fossil fuel power plants. Therefore, there is an urgent need to develop a power generation system that combines thermal engines and fuel cells to address the problems of insufficient thermal energy utilization in fuel cell power generation technology, environmental pollution caused by fossil fuel power generation, and limited resources. The ideal solution would be to use the high-grade waste heat from the fuel cell outlet to drive a turbine, fully leveraging the advantages of both power generation methods.

[0005] Summary of the Invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a power supply system based on the combination of a heat engine and a solid oxide fuel cell with high power generation efficiency and stable power supply; another purpose of the present invention is to provide a power supply method based on the combination of a heat engine and a solid oxide fuel cell.

[0007] Technical solution: The power supply system based on the combination of heat engine and solid oxide fuel cell described in the present invention includes a gas turbine generator module, a heat exchanger module and a fuel cell supply module; the gas turbine generator module is coupled to the heat exchange module through a turbine, and the turbine itself generates power for primary power generation, and heats the air by connecting to the heat exchange module. The heat exchange module outputs the heated air to the cathode of the solid oxide fuel cell of the fuel cell supply module by connecting to the fuel cell supply module, and the anode of the solid oxide fuel cell inputs the basic hydrocarbon fuel through a pipeline. The output end of the solid oxide fuel cell is connected to the combustion chamber for oxygen-deficient combustion power generation, and the products that are not fully burned are burned again to generate work by connecting to the turbine.

[0008] Among them, one end of the turbine is connected to a compressor to input air with a preset pressure value. The turbine preheats the air through its own exhaust gas and reheats it by connecting to an air preheater. The output end of the air preheater is connected to an air reheater to input the finally heated air into the cathode of the solid oxide fuel cell.

[0009] The basic hydrocarbon fuel is input to the injector through a pipeline, and the injector outputs the basic hydrocarbon fuel to a two-stage reforming reactor for conversion, and the converted product is input to the anode inlet of the solid oxide fuel cell.

[0010] The combustion chamber input end is connected to the two stages of the solid oxide fuel cell for oxygen-deficient combustion power generation, and the combustion chamber output end outputs the high-heat product to the air reheater for the next final heating of the air. The cooled product after heat exchange is transferred into it through the connection turbine for re-combustion.

[0011] The turbine is electrically driven by connecting to a compressor and an exhaust device, and excess power is output to a generator for storing electrical energy.

[0012] The gas generated after combustion in the turbine is cooled by connecting to a gas cooler, and the gas cooler is connected to an exhaust device to discharge the cooled gas into the atmosphere.

[0013] The air pressure increase range of the compressor is set to be between 2.0 MPa and 2.2 MPa.

[0014] The air pressure increase range of the exhaust port of the exhaust device is set to be in the range of 1.3MPa to 1.4MPa.

[0015] A power supply method based on a combination of a heat engine and a solid oxide fuel cell, comprising the following steps:

[0016] Step 1: Input of fuel: basic hydrocarbon fuel from pipeline enters into two-stage reforming reactor through injector for conversion; the converted product enters into anode inlet of solid oxide fuel cell;

[0017] Step 2: Compressed air is input. After being compressed to a set temperature by the compressor, atmospheric air enters the turbine for exhaust gas preheating and heat exchange in the regenerative air preheater. After passing through the air preheater, the air flows into the air reheater and is further heated to the specified temperature at the cathode inlet of the solid oxide fuel cell using the exhaust gas from the combustion chamber.

[0018] Step 3, combustion process, the fuel in the combustion chamber is the gas mixture at the outlet of the solid oxide fuel cell anode, which burns in the oxygen-deficient air entering the combustion chamber at the outlet of the solid oxide fuel cell cathode, generating electricity for user use;

[0019] Step 4: Reuse of combustion products. The cooled combustion products from the air reheater are introduced into the turbine and expanded to a pressure below atmospheric pressure. The gas enters the gas cooler through the gas side channel of the regenerative air preheater and is cooled to the required temperature. The cooled gas is compressed in the exhaust device and discharged into the atmosphere. The high-temperature and high-pressure gas in the air reheater is sent to the turbine to generate power. The turbine generates power to drive the compressor and exhaust device, and then transmits excess power to the generator, so that the four enter the working state.

[0020] The pressure of the fuel conversion process in the two-stage reforming reactor is determined by the pressure in the combustion chamber. The turbine expands to a pressure lower than atmospheric pressure after combustion, and the level of the pressure is determined by the exhaust device.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant improvements:

[0022] (1) The present invention can be directly modified on the basis of an existing thermal power plant. A solid fuel cell is installed on the basis of an existing single turbine power generation. The preheating generated by the turbine is used to generate the high-pressure gas required by the cathode of the solid fuel cell. After the solid fuel cell burns to generate electricity, the fully burned fuel heats the high-pressure gas and can also be burned again in the turbine to generate electricity. This combined power generation system promotes the transformation and upgrading of thermal power plants, avoids their closure and elimination and the resulting waste of resources, and can also reduce the initial investment cost of the equipment of the present invention, achieving better economic benefits. At the same time, the rational use of its pipelines can maintain a long service life and achieve stable power supply for several years.

[0023] (2) The fuel used in the fuel cell of the present invention comes from a wide range of sources, including methanol, diesel, gas, coal mine methane, propane, and oxygen-containing organic gases generated by industrial wastewater treatment plants, which are used for combustion and power generation. It has strong applicability and low operating costs.

[0024] (3) The present invention overcomes the drawbacks of existing fuel cell power plants and thermal power plants, achieving efficient energy utilization while saving energy and protecting the environment, and can also improve the overall efficiency of power generation by rationally controlling the pressure of the compressor and exhaust device.

[0025] (4) The advantage of the present invention is that it fully utilizes the potential of the gas mixture that is not fully burned at the outlet of the solid oxide fuel cell, thereby promoting the improvement of energy utilization efficiency and improving power generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic diagram of the overall structure of the present invention. DETAILED DESCRIPTION

[0027] As shown in FIG1 , the power supply system based on the combination of heat engine and solid oxide fuel cell in the present invention includes: a gas turbine generator module, a heat exchanger module and a fuel cell supply module. The gas turbine generator module is a regenerative gas turbine power generation device with a cooling device, and the gas turbine generator module includes a generator 1, a compressor 2, a turbine 3 and an exhaust device 4; the heat exchange module includes a gas cooler 5, an air preheater 6 and an air reheater 7; the fuel cell supply module includes a pipeline 8, an ejector 9, a two-stage reforming reactor 10, a solid oxide fuel cell 11 and a combustion chamber 12; the pipeline 8 for supplying basic hydrocarbon fuel is connected to the ejector 9, and the ejector 9 is connected to the first stage of the two-stage reforming reactor 10; the second part of the reforming reactor 10 is connected to the anode inlet of the solid oxide fuel cell 11; the compressor 2 is driven by the turbine 3, and the air is transferred from the air preheater 6, the air reheater 7 to the anode inlet of the solid oxide fuel cell 11; After two-stage heating, it is sent to the cathode inlet of the solid oxide fuel cell 11; the anode outlet and cathode outlet of the solid oxide fuel cell 11 are connected to the combustion chamber 12; the gas outlet of the combustion chamber 12 after combustion is connected to the air reheater 7, then connected to the turbine 3, then connected to the air preheater 6, then connected to the gas cooling device 5, and finally connected to the exhaust device 4.

[0028] In this embodiment, the gas turbine generator module is coupled to the heat exchange module via the turbine 13 and performs heat exchange with the fuel cell supply module via the heat exchange module.

[0029] The regenerative gas turbine power generation with an additional intercooler utilizes the energy of the gas mixture at the outlet of the solid oxide fuel cell 11 and in the related circuits to generate electricity.

[0030] The solid oxide fuel cell 11 is the main power generation module of the power supply device based on the combination of a heat engine and a solid oxide fuel cell, while the gas turbine generator module serves as an auxiliary power generation module.

[0031] A working method based on a combined power supply system of a heat engine and a solid oxide fuel cell, comprising: introducing a basic hydrocarbon fuel from a pipeline 8 into a two-stage reforming reactor 10 through an injector 9 for conversion, wherein the pressure of the fuel conversion process in the two-stage reforming reactor 10 is determined by the pressure in the combustion chamber 12; the converted product enters the anode inlet of the solid oxide fuel cell 11; atmospheric air is compressed to the required level by a compressor 2, and then enters a regenerative air preheater 6 for heat exchange, where it is preheated by the exhaust gas of a turbine 3; the turbine 3 generates electricity to drive the compressor 2 and the exhaust device 4, and transmits excess power to the generator 1; after passing through the air preheater 6, the air flows into an air reheater 7 and is further heated to a specified temperature at the cathode inlet of the solid oxide fuel cell 11 using the gas discharged from the combustion chamber 12.

[0032] The fuel of the combustion chamber 12 is the gas mixture at the anode outlet of the solid oxide fuel cell 11, which is burned in the oxygen-deficient air entering the combustion chamber 12 from the cathode outlet of the solid oxide fuel cell 11 to generate electricity for users; the cooled combustion products from the air reheater 7 are introduced into the turbine 3 and expanded to a pressure significantly lower than atmospheric pressure; the pressure is determined by the gas boost level selected in the exhaust device 4; the gas enters the gas cooler 5 through the gas side channel of the regenerated air preheater 6, is cooled to the required temperature, and the cooled gas is compressed in the exhaust device 4 and discharged into the atmosphere.

[0033] The high-temperature and high-pressure gas in the air reheater 7 is sent to the turbine 3 to generate electricity. The turbine 3 generates electricity to drive the compressor 2 and the exhaust device 4, and then transmits the excess power to the generator 1. The four thus enter the working state.

[0034] In this embodiment, the air pressure increase amplitude of the compressor 2 is set within the range of 2.0-2.2MPa, and the air pressure increase amplitude of the exhaust port of the exhaust device 4 is set within the range of 1.3-1.4MPa; by setting the optimal value range for the above parameters, not only the pressure inside the fuel cell stack is minimized to no more than 0.18-0.20MPa, but also the temperature before the engine turbine is maintained within the ideal gas temperature range of 1050-1090K, and the power generation efficiency can be increased by up to 19%.

Claims

1. A combined power supply system based on a heat engine and a solid oxide fuel cell, characterized in that, It includes a gas turbine generator module, a heat exchanger module, and a fuel cell supply module; the gas turbine generator module is coupled to the heat exchange module through a turbine (3). The turbine (3) generates power through its own work for primary power generation and heats the air by connecting to the heat exchange module. The heat exchange module outputs the heated air to the cathode of the solid oxide fuel cell (11) in the fuel cell supply module by connecting to the fuel cell supply module. The anode of the solid oxide fuel cell (11) inputs the basic hydrocarbon fuel through a pipeline, and the output end of the solid oxide fuel cell (11) is connected to a combustion chamber (12) for anoxic combustion power generation. The unburned products are connected to the turbine (3) for re-combustion work.

2. The combined power supply system based on a heat engine and a solid oxide fuel cell according to claim 1, wherein One end of the turbine (3) inputs air with a preset pressure value through a connected compressor (2). The turbine (3) preheats the air with its own exhaust gas and further preheats it through a connected air preheater (6). The output end of the air preheater (6) is connected to an air reheater (7) to input the finally heated air to the cathode of the solid oxide fuel cell (11).

3. A combined power supply system based on a heat engine and a solid oxide fuel cell according to claim 1, characterized in that, The basic hydrocarbon fuel is input into an injector (9) through a pipeline (8). The injector (9) outputs the basic hydrocarbon fuel into a two-stage reforming reactor (10) for conversion, and the converted products are input into the anode inlet of the solid oxide fuel cell (11).

4. A combined power supply system based on a heat engine and a solid oxide fuel cell according to claim 1, characterized in that, The input end of the combustion chamber (12) is connected to the two stages of the solid oxide fuel cell (11) for anoxic combustion power generation. The output end of the combustion chamber (12) outputs the high-temperature products into the air reheater (7) for the final heating of the next air. The cooled products after heat exchange are connected to the turbine (3) and introduced into it for re-combustion.

5. A combined power supply system based on a heat engine and a solid oxide fuel cell according to claim 4, characterized in that, The turbine (3) is electrically driven by connecting to a compressor (2) and an exhaust device (4), and the excess power is output to a generator (1) for electrical energy storage.

6. A combined power supply system based on a heat engine and a solid oxide fuel cell according to claim 4, characterized in that, The gas generated after the combustion of the turbine (3) is cooled through a connected gas cooler (5). The gas cooler (5) is connected to the exhaust device (4) to discharge the cooled gas into the atmosphere.

7. A combined power supply system based on a heat engine and a solid oxide fuel cell according to claim 2, characterized in that, The range of the air pressure increase of the compressor (2) is set to 2.0 MPa - 2.2 MPa.

8. A combined power supply system based on a heat engine and a solid oxide fuel cell according to claim 6, characterized in that, The range of the air pressure increase at the exhaust port of the exhaust device (4) is set to 1.3 MPa - 1.4 MPa.

9. A power supply method based on the combination of a heat engine and a solid oxide fuel cell according to any one of claims 1 to 8, characterized in that, It includes the following steps: Step 1: Input of fuel. The basic hydrocarbon fuel from the pipeline (8) enters the two-stage reforming reactor (10) through the injector (9) for conversion; the converted products enter the anode inlet of the solid oxide fuel cell (11). Step 2: Input of compressed air. After the atmospheric air is compressed by the compressor (2) to a set degree, it enters the turbine (3) for exhaust gas preheating and heat exchange with the regenerative air preheater (6). After passing through the air preheater (6), the air flows into the air reheater (7) to utilize the gas discharged from the combustion chamber (12) and is further heated to the specified temperature at the cathode inlet of the solid oxide fuel cell (11). Step 3: Combustion process. The fuel in the combustion chamber (12) is the gas mixture at the anode outlet of the solid oxide fuel cell (11), which burns in the oxygen-deficient air entering the combustion chamber (12) at the cathode outlet of the solid oxide fuel cell (11) to generate electric energy for user consumption. Step 4: Reutilization of combustion products. The cooled combustion products from the air reheater (7) are introduced into the turbine (3) and expanded to a pressure below atmospheric pressure. The gas then enters the gas cooler (5) through the gas-side channel of the regenerative air preheater (6) and is cooled to the required temperature. The cooled gas is compressed in the exhaust device (4) and discharged into the atmosphere. The high-temperature and high-pressure gas in the air reheater (7) is sent to the turbine (3) to do work and generate electricity. The turbine (3) drives the compressor (2) and the exhaust device (3) to generate electricity, and then transmits the excess power to the generator (1), and the four enter the working state accordingly.

10. A combined power supply method based on a heat engine and a solid oxide fuel cell according to claim 9, characterized in that, The pressure of the fuel conversion process in the two-stage reforming reactor (10) is determined by the pressure in the combustion chamber (12), and the turbine (3) expands to a pressure below atmospheric pressure after combustion, and the level of this pressure is determined by the exhaust device (4).

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