Gas turbine and solid oxide fuel cell combined cycle system

Abstract

The invention provides a gas turbine and solid oxide fuel cell combined cycle system. The gas turbine and solid oxide fuel cell combined cycle system comprises a gas turbine engine mainly composed of a gas compressor, a main combustion chamber, a turbine, a fuel tank and the like; a heat exchange system is mainly composed of liquid ammonia storage equipment, an integrated heat exchanger and a cracking device, the integrated heat exchanger comprises an air-air heat exchanger and an ammonia-air heat exchanger, the air-air heat exchanger is communicated with an outer culvert air entraining and gas compressor, and the ammonia-air heat exchanger is communicated with the liquid ammonia storage equipment, the cracking device and a turbine. The air-air heat exchanger is communicated with the ammonia-air heat exchanger in the integrated heat exchanger; the cracking device is communicated with the main combustion chamber; the airborne equipment power supply system is mainly composed of a solid oxide fuel cell, a cell and an electric power system, the solid oxide fuel cell is connected with the air-air heat exchanger and the ammonia-air heat exchanger of the integrated heat exchanger and used for generating electric energy, and the cell and the electric power system are connected with the solid oxide fuel cell and used for conducting electric energy storage and electric power control.

Description

Technical Field

[0001] This application belongs to the technical field of aero-engine hybrid power technology, and particularly relates to a combined cycle system of a gas turbine and a solid oxide fuel cell. Background Art

[0002] Increasing the turbine inlet temperature is one of the main technical ways to improve the performance of gas turbine engines. In actual operation of the engine, the turbine inlet temperature far exceeds the allowable temperature of the turbine blade material itself. To address this problem, the common approach is to extract low-temperature air from the compressor and introduce it into the turbine blades for cooling so that they can withstand the high-temperature external environment.

[0003] With the continuous improvement of engine performance requirements, the turbine inlet temperature has been further increased. The existing materials and their processing technologies cannot solve the problem of high-temperature resistance of turbine blades. Therefore, in the prior art, on the basis of pre-cooling with turbine cooling air, the temperature of the cooling air is reduced (the quality of the cooling air is improved) to increase the turbine inlet temperature, that is, the CCA technology (Cooled Cooling Air).

[0004] The existing aero-engines mainly use aviation kerosene as the cooling medium for the CCA technology. Its advantage is that there is no need to consider the problem of increasing the "dead weight" caused by introducing a third medium. As Figure 1 shown in the schematic diagram of the engine cycle system 100 considering pre-cooling of cooling air and engine power extraction in the prior art, the air entering the engine is compressed by the compressor 101 and then enters the main combustion chamber 102, where it is mixed with fuel and burned. After that, the high-temperature gas enters the turbine 103 to expand and do work. In order to generate greater thrust, it is burned again in the afterburner 104, and then the gas is discharged from the engine to generate thrust, which is represented by the flow path a in the figure; in order to reduce the temperature of hot-end components such as the turbine 103, generally a part of the fuel flows through the air-oil heat exchanger 105 to cool the cooling air introduced from the compressor 101, reducing the temperature of this part of the bleed air and improving its cooling capacity for the turbine blades, thereby improving the performance and reliability of the hot-end components, which is represented by the flow path b in the figure; at the same time, the power extraction device 107 extracts the shaft work of the engine and combines it with the battery 108 and the power system 109 to provide auxiliary energy for other aircraft electronic devices or serve as electrical energy storage, which is represented by the flow path c in the figure.

[0005] However, the above engine system mainly has the following three problems:

[0006] 1) Insufficient cooling capacity

[0007] In the existing engine system, aviation kerosene is used to pre-cool the cooling air, which can reduce the temperature of the cooling air to a certain extent. However, since aviation kerosene will coke at high temperatures, the heat exchange temperature range is limited and the heat exchange capacity is limited. Therefore, the method of using aviation kerosene as a pre-cooling medium for air-oil heat exchange to increase the temperature before the turbine is restricted;

[0008] 2) Insufficient power supply

[0009] The power supply or electrical energy reserve of the engine system mainly comes from the extraction of engine shaft work. This process means that the shaft work used for engine propulsion is reduced. Therefore, in order to ensure the overall performance of the engine, the power extraction amount will be limited, and the generated electrical power or electrical energy reserve is also limited; for future aviation power systems that pursue both speed and range, the advanced avionics systems, weapon systems (such as laser weapons), etc. have huge power demands, and the current engine system cannot increase the power extraction of the engine while ensuring the engine performance;

[0010] 3) High carbon emissions

[0011] The fuel used in the existing engine system is aviation kerosene. As a hydrocarbon fuel, it has high carbon emissions and insufficient cleanliness. If the electrical power output is to be increased without sacrificing the engine performance, the carbon emissions will exceed the standard. Summary of the Invention

[0012] The purpose of the present application is to provide a combined cycle system of a gas turbine and a solid oxide fuel cell to solve or alleviate at least one problem in the background technology.

[0013] The technical solution of the present application is: a combined cycle system of a gas turbine and a solid oxide fuel cell, comprising:

[0014] A gas turbine engine mainly composed of a compressor, a main combustion chamber, a turbine and a fuel tank, wherein the compressor, the main combustion chamber and the turbine are arranged in sequence along the engine axis direction, and the fuel tank is connected to the main combustion chamber to supply fuel to the main combustion chamber;

[0015] A heat exchange system mainly composed of a liquid ammonia storage device, an integrated heat exchanger and a cracking device. Among them, the integrated heat exchanger includes an air-air heat exchanger in the front section and an ammonia-air heat exchanger in the rear section. The air-air heat exchanger is connected to the bypass air and the compressor, the ammonia-air heat exchanger is connected to the liquid ammonia storage device, the cracking device and the turbine, the air-air heat exchanger is internally connected to the ammonia-air heat exchanger in the integrated heat exchanger, and the cracking device is connected to the main combustion chamber; and

[0016] An airborne equipment power supply system mainly composed of a solid oxide fuel cell, a battery and a power system, wherein the solid oxide fuel cell is connected to the air-air heat exchanger and the ammonia-air heat exchanger of the integrated heat exchanger, and is used to react the high-temperature bypass bleed air that has undergone preliminary heat exchange in the air-air heat exchanger with the high-temperature ammonia gas generated by the secondary heat exchange in the ammonia-air heat exchanger to generate electric energy, and the battery and the power system are connected to the solid oxide fuel cell and are used to store and control the power after the solid oxide fuel cell generates electric energy.

[0017] In a preferred embodiment of the present application, the gas turbine engine further includes an afterburner, and the afterburner is arranged behind the turbine and is supplied with fuel through the fuel tank.

[0018] In a preferred embodiment of the present application, the solid oxide fuel cell is communicated with the afterburner and is used to discharge the reacted ammonia gas and to perform secondary combustion of the generated hydrogen gas in the afterburner.

[0019] In a preferred embodiment of the present application, the solid oxide fuel cell is an ammonia-based solid oxide fuel cell.

[0020] In a preferred embodiment of the present application, three flow paths are generated during the operation of the combined cycle system.

[0021] In a preferred embodiment of the present application, the first flow path is as follows:

[0022] The mainstream air entering the engine is compressed by the compressor and then enters the main combustion chamber, mixes with the fuel provided by the fuel tank and burns, and then the high-temperature gas enters the turbine to expand and do work. When the gas turbine engine includes an afterburner, the high-temperature gas will enter the afterburner to burn again to generate greater thrust, and finally the gas is discharged from the engine.

[0023] In a preferred embodiment of the present application, the second flow path is as follows:

[0024] A part of the cold air is drawn from the compressor to cool the turbine components. The cold air is introduced into the integrated heat exchanger, and in the air-air heat exchanger, the relatively low-temperature bypass bleed air cools the compressor bleed air and heats up, and then the bypass bleed air enters the solid oxide fuel cell to generate electricity;

[0025] The cold air introduced by the compressor continues to flow in the integrated heat exchanger and enters the ammonia-air heat exchanger, exchanges heat with the liquid ammonia introduced from the liquid ammonia storage device, further reduces the temperature of the cold air and then flows to the turbine components;

[0026] The liquid ammonia is converted into high-temperature ammonia gas after heat exchange. A part of the high-temperature ammonia gas is cracked by the cracking device to generate nitrogen and hydrogen. The nitrogen is discharged into the mainstream or the atmosphere, and the hydrogen is introduced into the main combustion chamber for combustion.

[0027] In a preferred embodiment of the present application, the third flow path is as follows:

[0028] Another part of the high-temperature ammonia gas flowing out of the ammonia-air heat exchanger of the integrated heat exchanger flows to the solid oxide fuel cell, reacts with the bypass air that has been heat-exchanged in the air-air heat exchanger in the solid oxide fuel cell to generate electric energy, and the solid oxide fuel cell, together with the battery and the power system, provides electric energy supply for the airborne equipment or serves as electric energy storage;

[0029] The gas discharged from the solid oxide fuel cell contains hydrogen and part of the unreacted air, and is discharged from the engine after being burned again by introducing it into the afterburner.

[0030] The combined cycle system of the gas turbine and the solid oxide fuel cell provided by the present application introduces a third medium, ammonia, as the cooling medium of the system. By combining ammonia SOFC power generation and introducing its products into the engine system for combustion, the "multi-use of ammonia" is realized, and the following problems are solved:

[0031] 1) Solved the problem of insufficient cooling capacity of the cooling air in the air-oil heat exchange

[0032] In the existing engine cycle system, due to the limitation of the kerosene coking problem, the cooling air in the air-oil heat exchange is insufficiently cooled. In the present application, ammonia is used as the cooling medium for the cooling air of the hot-end components, converting the air-oil heat exchange into ammonia-air heat exchange, and avoiding the kerosene coking problem from the source;

[0033] Secondly, ammonia has a high phase change latent heat. Liquid ammonia undergoes phase change in the heat exchanger for heat exchange, and its heat exchange capacity is higher than that of aviation kerosene. Therefore, the cooling air after heat exchange with ammonia has a higher cooling quality, can achieve a better cooling effect on the turbine components, is more conducive to increasing the turbine inlet temperature, and thus improves the engine performance. At the same time, the higher heat exchange capacity is also conducive to improving the compactness of the heat exchanger and reducing the aircraft structure weight;

[0034] 2) Solved the problem of insufficient power supply of the existing power system

[0035] Existing engine cycle systems are unable to provide a large power supply due to limitations in the power extraction amount. In this application, further utilization of the introduced ammonia medium is carried out. A solid oxide fuel cell (SOFC) based on ammonia medium is used as a power generation method to provide electrical energy and electrical energy storage for the engine system. SOFC has a high power generation efficiency (usually exceeding 60%, while the Brayton cycle of aeroengines is about 40%) and can provide a large power. Thus, the shaft work extraction for power supply and electrical energy storage in the conventional engine cycle system can be eliminated, and the engine shaft work can be maximally applied to the aircraft propulsion system. The hybrid cycle system of this application can achieve performance improvement effects such as thrust increase, thermal efficiency improvement, and fuel consumption rate reduction on the basis of the original engine cycle system;

[0036] 3) Solve the problem of high engine carbon emissions

[0037] In this application, the reaction products of the solid oxide fuel cell (SOFC) contain combustible hydrogen. Hydrogen has the advantages of high calorific value and easy combustion. By introducing it into the afterburner for further combustion, the engine thrust can be increased. At the same time, hydrogen combustion does not contain carbon. Under the condition of the same system thrust, the engine fuel consumption rate can be reduced, carbon emissions can be reduced, "multi-uses of ammonia" are realized, and the problem of "dead weight" caused by introducing a third medium is avoided. Brief Description of the Drawings

[0038] To more clearly illustrate the technical solutions provided by this application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0039] Figure 1 It is a schematic diagram of an existing engine cycle system.

[0040] Figure 2 It is a schematic diagram of the combined cycle system of a gas turbine and a solid oxide fuel cell of this application. Detailed Embodiments

[0041] To make the purpose, technical solutions, and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the drawings in the embodiments of this application.

[0042] To solve the problems of insufficient cooling air cooling capacity in air-oil heat exchange in the prior art, insufficient power supply of the existing power system, and high engine carbon emissions, this application proposes a combined cycle system of a gas turbine - solid oxide fuel cell based on ammonia medium. By introducing ammonia as the system cooling medium and fuel on the basis of the conventional engine system and combining the gas turbine and the fuel cell, a hybrid power system is formed.

[0043] AsFigure 2 As shown in Figure 2 , the combined cycle system of a gas turbine - solid oxide fuel cell based on an ammonia medium provided by this application, this combined cycle system 200 includes:

[0044] A gas turbine engine mainly composed of a compressor 201, a main combustion chamber 202, a turbine 203, a fuel tank 206, etc. The compressor 201, the main combustion chamber 202, and the turbine 203 are arranged in sequence along the engine axis direction. The fuel tank 206 is connected to the main combustion chamber 202 through an oil pipe for supplying fuel to the main combustion chamber 202; in some embodiments of this application, the gas turbine engine sometimes also includes an afterburner 204. At this time, the fuel tank 206 will also be connected to the afterburner 204 through an oil pipe and supply fuel to the afterburner 204 at the same time;

[0045] A heat exchange system mainly composed of a liquid ammonia storage device 211, an integrated heat exchanger 205, and a cracking device 210. Among them, the integrated heat exchanger 205 includes an air - air heat exchanger 212 in the front section and an ammonia - air heat exchanger 213 in the rear section. The air - air heat exchanger 212 is connected to the bypass air bleed and the compressor 201, and the ammonia - air heat exchanger 213 is connected to the liquid ammonia storage device 211, the cracking device 210, and the turbine 203. The air - air heat exchanger 212 and the ammonia - air heat exchanger 213 are connected inside the integrated heat exchanger 205, and the cracking device 210 is connected to the main combustion chamber 202; and

[0046] An airborne equipment power supply system mainly composed of a solid oxide fuel cell 207 (SOFC), a battery 208 (aircraft electric energy reserve), and a power system 209. The solid oxide fuel cell 207 is connected to the air - air heat exchanger 212 and the ammonia - air heat exchanger 213 of the integrated heat exchanger 205, and can react the high - temperature bypass air bleed that has been preliminarily heat - exchanged in the air - air heat exchanger 212 with the high - temperature ammonia gas generated by secondary heat - exchange in the ammonia - air heat exchanger 213 to generate electric energy. The battery 208 and the power system 209 are connected to the solid oxide fuel cell 207 for storing and controlling electric power after the solid oxide fuel cell 207 generates electric energy.

[0047] The operation process of the combined cycle system of the gas turbine and the solid oxide fuel cell of this application is as follows:

[0048] 1) The mainstream air entering the engine is compressed by the compressor 201 and then enters the main combustion chamber 202, mixes with the fuel provided by the fuel tank 206 and burns. Then the high - temperature gas enters the turbine 203 to expand and do work. When the gas turbine engine includes an afterburner 204, the high - temperature gas will enter the afterburner 204 to burn again to generate greater thrust. Finally, the gas is discharged from the engine. This process is represented by flow path a in Figure 2 ;

[0049] 2) A part of the cold air is drawn from the compressor 201 to cool the turbine components. To improve the quality of the cooling air, this cooling air is introduced into the integrated heat exchanger 205. In the air-air heat exchanger 212 of the integrated heat exchanger 205, the relatively low-temperature bypass air cools the air drawn from the compressor 201 and then heats up. After that, the bypass air enters the solid oxide fuel cell 207 to generate electricity;

[0050] The air drawn from the compressor 201 continues to flow in the integrated heat exchanger 205 and enters the ammonia-air heat exchanger 213, where it exchanges heat with the ammonia introduced from the liquid ammonia storage device 211, further reducing the temperature of the cooling air. The further cooled gas flows towards the turbine components, thereby improving the cooling capacity of the cooling air for the turbine blades and enhancing the safety and reliability of the hot-end components;

[0051] The liquid ammonia is converted into high-temperature ammonia gas through boiling heat exchange. A part of the high-temperature ammonia gas is cracked by the cracking device 210 to generate nitrogen and hydrogen. The nitrogen is discharged into the mainstream or the atmosphere, and the hydrogen is introduced into the main combustion chamber 202 for combustion. The whole process is Figure 2 represented by the flow path b;

[0052] 3) Another part of the high-temperature ammonia gas flowing out of the ammonia-air heat exchanger 213 at the rear section of the integrated heat exchanger 205 flows towards the solid oxide fuel cell 207, and reacts with the bypass air (mainly using the oxygen therein) that has been heat-exchanged in the air-air heat exchanger 212 at the front section of the integrated heat exchanger 205 in the solid oxide fuel cell 207 (ideally, it completely reacts to generate electricity, and in practice, some hydrogen will be generated). The solid oxide fuel cell 207, together with the battery 208 and the power system 209, can provide electrical energy supply for the aircraft's on-board equipment or serve as electrical energy storage;

[0053] The gas discharged from the solid oxide fuel cell 207 contains combustible hydrogen and some unreacted air. After being introduced into the afterburner 204 again for combustion and then discharged from the engine, the system thrust is further increased. The whole process is Figure 2 represented by the flow path c;

[0054] The combined cycle system of the gas turbine and the solid oxide fuel cell provided by this application introduces a third medium, ammonia, as the cooling medium of the system. By combining ammonia SOFC power generation and introducing its products into the engine system for combustion, the "multiple uses of ammonia" is realized, and the following problems are solved:

[0055] 1) Solved the problem of insufficient cooling capacity of the cooling air in the air-oil heat exchange

[0056] In the existing engine cycle system, due to the limitation of the kerosene coking problem, the cooling air in the air-oil heat exchange is insufficiently cooled. In this application, ammonia is used as the cooling medium for cooling the hot-end components, converting the air-oil heat exchange into ammonia-air heat exchange, thus avoiding the kerosene coking problem at the source;

[0057] Secondly, ammonia has a high phase change latent heat. Liquid ammonia exchanges heat by undergoing a phase change in the heat exchanger, and its heat exchange capacity is higher than that of aviation kerosene. Therefore, the cooling air after exchanging heat with ammonia has a higher cooling quality, which can achieve a better cooling effect on the turbine components, is more conducive to increasing the temperature before the turbine, and further improves the engine performance. At the same time, the higher heat exchange capacity is also conducive to improving the compactness of the heat exchanger and reducing the aircraft structural weight;

[0058] 2) Solve the problem of insufficient power supply in the existing power system

[0059] In the existing engine cycle system, due to the limitation of the power extraction value, it is unable to provide a large power supply. In this application, the introduced ammonia medium is further utilized, and a solid oxide fuel cell (SOFC) based on the ammonia medium is used as the power generation method to provide electrical energy and electrical energy storage for the engine system. SOFC has a high power generation efficiency (usually exceeding 60%, while the Brayton cycle of aero engines is about 40%) and can provide a large power. Therefore, the shaft work extraction for power supply and electrical energy storage in the conventional engine cycle system can be omitted, and the engine shaft work can be maximally applied to the aircraft propulsion system. The hybrid cycle system of this application can achieve performance improvement effects such as thrust increase, thermal efficiency improvement, and fuel consumption rate reduction on the basis of the original engine cycle system;

[0060] 3) Solve the problem of high engine carbon emissions

[0061] In this application, the reaction product of the solid oxide fuel cell (SOFC) contains combustible hydrogen. Hydrogen has the advantages of high calorific value and easy combustion. By introducing it into the afterburner for further combustion, the engine thrust can be increased. At the same time, hydrogen combustion does not contain carbon. Under the condition of the same system thrust, the engine fuel consumption rate can be reduced, carbon emissions can be reduced, "multiple uses of ammonia" are realized, and the problem of "dead weight" brought by introducing a third medium is avoided.

[0062] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claimed rights.

Claims

1. A combined cycle system of a gas turbine and a solid oxide fuel cell, characterized in that, Comprising: A gas turbine engine mainly composed of a compressor (201), a main combustion chamber (202), a turbine (203) and a fuel tank (206), wherein the compressor (201), the main combustion chamber (202) and the turbine (203) are arranged in sequence along the engine axis direction, and the fuel tank (206) is connected to the main combustion chamber (202) to supply fuel to the main combustion chamber (202); A heat exchange system mainly composed of a liquid ammonia storage device (211), an integrated heat exchanger (205) and a cracking device (210). Among them, the integrated heat exchanger (205) includes an air-air heat exchanger (212) at the front section and an ammonia-air heat exchanger (213) at the rear section. The air-air heat exchanger (212) is connected to the external bypass air and the compressor (201), and the ammonia-air heat exchanger (213) is connected to the liquid ammonia storage device (211), the cracking device (210) and the turbine (203). The air-air heat exchanger (212) and the ammonia-air heat exchanger (213) are connected inside the integrated heat exchanger (205), and the cracking device (210) is connected to the main combustion chamber (202); and An airborne equipment power supply system mainly composed of a solid oxide fuel cell (207), a battery (208) and a power system (209). The solid oxide fuel cell (207) is connected to the air-air heat exchanger (212) and the ammonia-air heat exchanger (213) of the integrated heat exchanger (205), and is used to react the high-temperature external bypass air initially heat-exchanged in the air-air heat exchanger (212) with the high-temperature ammonia gas generated by secondary heat exchange in the ammonia-air heat exchanger (213) to generate electric energy. The battery (208) and the power system (209) are connected to the solid oxide fuel cell (207) and are used to store and control the power after the solid oxide fuel cell (207) generates electric energy.

2. The combined cycle system of a gas turbine and a solid oxide fuel cell according to claim 1, characterized in that The gas turbine engine further includes an afterburner (204), and the afterburner (204) is arranged at the rear side of the turbine (203), and fuel is supplied to the afterburner (204) through the fuel tank (206).

3. The combined cycle system of a gas turbine and a solid oxide fuel cell according to claim 2, characterized in that, The solid oxide fuel cell (207) is connected to the afterburner (204) and is used to discharge the reacted ammonia gas and to perform secondary combustion of the generated hydrogen gas in the afterburner (204).

4. The combined cycle system of a gas turbine and a solid oxide fuel cell according to any one of claims 1 to 3, characterized in that, The solid oxide fuel cell (207) is an ammonia-based solid oxide fuel cell.

5. The combined cycle system of a gas turbine and a solid oxide fuel cell according to claim 4, characterized in that, The combined cycle system (200) generates three flow paths during operation.

6. The combined cycle system of a gas turbine and a solid oxide fuel cell according to claim 5, characterized in that, The first flow path is: The mainstream air entering the engine is compressed by the compressor (201) and then enters the main combustion chamber (202), mixes with the fuel provided by the fuel tank (206) and burns. Then the high-temperature gas enters the turbine (203) to expand and do work. When the gas turbine engine includes an afterburner (204), the high-temperature gas will enter the afterburner (204) to burn again to generate greater thrust, and finally the gas is discharged from the engine.

7. The combined cycle system of a gas turbine and a solid oxide fuel cell according to claim 5, characterized in that, The second flow path is: A part of the cold air is drawn from the compressor (201) to cool the turbine components. The cold air is introduced into the integrated heat exchanger (205), and in the air-air heat exchanger (212), the relatively low-temperature bypass air cools the air drawn from the compressor (201) and then heats up. After that, the bypass air enters the solid oxide fuel cell (207) to generate electricity. The cold air drawn by the compressor (201) continues to flow in the integrated heat exchanger (205) and then enters the ammonia-air heat exchanger (213), where it exchanges heat with the liquid ammonia introduced from the liquid ammonia storage device (211). After further reducing the temperature of the cold air, it flows towards the turbine components. The liquid ammonia is converted into high-temperature ammonia gas after heat exchange. A part of the high-temperature ammonia gas is cracked by the cracking device (210) to generate nitrogen and hydrogen. The nitrogen is discharged into the mainstream or the atmosphere, and the hydrogen is introduced into the main combustion chamber (202) for combustion.

8. The combined cycle system of a gas turbine and a solid oxide fuel cell according to claim 5, characterized in that, The third flow path is as follows: Another part of the high-temperature ammonia gas flowing out of the ammonia-air heat exchanger (213) of the integrated heat exchanger (205) flows towards the solid oxide fuel cell (207), and reacts with the bypass air that has been heat-exchanged in the air-air heat exchanger (212) in the solid oxide fuel cell (207) to generate electric energy. The solid oxide fuel cell (207), together with the battery (208) and the power system (209), provides power supply for the airborne equipment or serves as power storage. The gas discharged from the solid oxide fuel cell (207) contains hydrogen and some unreacted air, which is discharged from the engine after being burned again by being introduced into the afterburner (204).

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