Hydrogen-fueled compressed air energy storage system and method

Abstract

The application discloses a compressed air energy storage system and method with hydrogen afterburning, and belongs to the energy storage field.The system comprises a compression module, an expansion power generation module, a heat storage module, a heat release module, a performance heating module, a steam-water thermodynamic cycle module and a cooling module.The compression module is used for compressing and storing air.The expansion power generation module is used for releasing the compressed air into a turbine for expansion and power generation.The heat storage module is used for absorbing and storing heat generated in the air compression process.The heat release module is used for releasing the stored heat to air and hydrogen.The performance heating module is used for heating hydrogen.The steam-water thermodynamic cycle module is used for absorbing flue gas heat for further expansion and power generation.The compressed air energy storage system and method with hydrogen afterburning greatly reduce the flow of compressed air, reduce the parameters of the air storage, improve the cycle efficiency of long-time energy storage, and make the system more flexible and suitable for the requirements of a new power system.

Description

Technical Field

[0001] This invention belongs to the field of energy storage, and particularly relates to a compressed air energy storage system and method for hydrogen-assisted combustion. Background Technology

[0002] Currently, energy storage technology is developing rapidly, especially non-combustion compressed air energy storage systems, which are constantly evolving towards larger capacities and higher parameters. However, due to geographical limitations, the development of large-scale non-combustion compressed air energy storage technology has encountered bottlenecks, with long-term energy storage leading to reduced efficiency. Conventional compressed air energy storage systems that use natural gas for combustion utilize a mixture of high-pressure air and natural gas to generate high-temperature, high-pressure flue gas, which expands in a gas turbine to generate electricity. This process requires the use of natural gas for combustion, thus facing pressure regarding carbon emissions. Furthermore, the dependence on natural gas limits the system's application.

[0003] Existing patents include energy storage systems that combine compressed air energy storage technology with hydrogen energy technology. These systems combine the large-scale energy storage capacity of compressed air energy storage with the environmentally friendly properties of hydrogen. Compared to traditional natural gas-based afterburning systems, hydrogen-based afterburning systems outperform traditional systems in terms of discharge time, energy density, and efficiency, and do not produce greenhouse gas emissions. However, because hydrogen is more expensive than natural gas, the average cost of pure hydrogen-based afterburning compressed air energy storage systems is also higher, which limits their commercial application.

[0004] Existing hydrogen-assisted combustion compressed air energy storage systems, after generating electricity through turbine expansion, still exhibit high flue gas temperatures, resulting in low energy utilization. During compression, some heat is not absorbed during expansion, leading to heat waste. Most importantly, existing combustion-based energy storage systems separate the compression and expansion processes, failing to respond to grid demands for flexible power plant operation and hindering rapid transitions in operating modes, such as from energy storage to energy release. Summary of the Invention

[0005] The purpose of this invention is to provide a hydrogen-assisted combustion compressed air energy storage system and method to solve the problems of excessively large gas storage capacity, excessively high parameters, excessively large main and auxiliary equipment capacity, and poor long-term energy storage effect in large-scale compressed air energy storage power plants. It also solves the problem that existing hydrogen-assisted combustion compressed air energy storage systems cannot quickly change their operating modes.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A hydrogen-assisted combustion compressed air energy storage system includes a compression module, an expansion power generation module, a heat storage module, a heat release module, a performance heating module, a steam-water thermal circulation module, and a cooling module. The compression module comprises a first air compressor, a first heat exchanger, a second air compressor, and a second heat exchanger connected in series. The expansion power generation module comprises a gas storage tank, a third heat exchanger, a mixing combustion chamber, a flue gas turbine, and a flue gas heat exchanger connected in series, with the gas storage tank connected to the second heat exchanger. The heat storage module comprises a cold water tank, a cold water pump, a first heat exchanger, a second heat exchanger, and a hot water tank connected in series. The heat release module comprises a hot water tank, a hot water pump, a third heat exchanger, a fifth heat exchanger, and a cold water tank. The performance heating module comprises a flue gas heat exchanger, a first circulation pump, and a fourth heat exchanger connected in a ring. The steam-water thermal circulation module comprises a flue gas heat exchanger, a steam turbine, a condenser, and a second circulation pump connected in a ring. The cooling module comprises a condenser, a cooling tower, and a third circulation pump connected in a ring.

[0008] A further improvement of the technical solution of the present invention is that: a first shut-off valve and a third shut-off valve are respectively provided on the connecting pipes of the first air compressor and the first heat exchanger and the connecting pipes of the second air compressor and the gas storage tank in the compression module.

[0009] A further improvement of the technical solution of the present invention is that the first air compressor and the third heat exchanger are connected by a pipeline, and a second shut-off valve is provided on the pipeline.

[0010] A further improvement to the technical solution of the present invention is that: the hydrogen source is connected to the fifth heat exchanger, and the fifth heat exchanger is connected in sequence to the fourth heat exchanger and the mixing combustion chamber.

[0011] A further improvement of the technical solution of the present invention is that: a fourth shut-off valve is provided on the connecting pipe between the gas storage tank and the third heat exchanger in the expansion power generation module; the flue gas turbine drives the generator; and the steam turbine of the steam-water thermal circulation module is connected to the generator.

[0012] A further improvement to the technical solution of the present invention is that the power generation settings of the first circulating pump are interlocked with those of the flue gas turbine and the steam turbine.

[0013] A further improvement of the technical solution of the present invention is that: the compression module is used to compress and store air; the expansion power generation module is used to release the compressed air into the turbine to expand and do work; the heat storage module is used to absorb and store the heat generated during the air compression process; the heat release module is used to release the stored heat to the air and hydrogen; the performance heater module is used to heat the hydrogen; and the steam-water thermal circulation module is used to absorb the heat of the flue gas for further expansion and work.

[0014] A method for storing compressed air with hydrogen combustion, comprising the following arrangement:

[0015] S1. During the off-peak period of electrical load, the temperature of the atmosphere rises after being compressed by the first air compressor, opening the first and third shut-off valves and closing the second and fourth shut-off valves. The high-temperature air decreases in temperature after passing through the first heat exchanger, increases in temperature after being compressed by the second air compressor, decreases in temperature after entering the second heat exchanger, and is finally stored in the gas storage tank.

[0016] S2. Simultaneously with the above S1 process, the cold water pump pressurizes the water in the cold water tank, and then divides it into two paths, which enter the first heat exchanger and the second heat exchanger respectively, absorbing the temperature released by the high-temperature air during S1 process. The water is heated to become high-temperature hot water and then stored in the hot water tank.

[0017] S3. During the peak electrical load phase, the fourth shut-off valve is opened and the third shut-off valve is closed. At this time, the high-pressure low-temperature air in the gas storage tank first absorbs heat and heats up through the third heat exchanger, and then enters the mixing combustion chamber to mix and burn with the hydrogen that has been heated by passing through the fifth and fourth heat exchangers. The resulting high-temperature flue gas enters the flue gas turbine to expand and do work, and then enters the flue gas heat exchanger to release heat and become low-temperature flue gas discharged into the atmosphere.

[0018] S4. Simultaneously with the above S3 process, the hot water pump pressurizes the water in the hot water tank and sends it into the third heat exchanger, where it releases heat to the low-temperature air coming out of the gas storage tank. The water after heat exchange enters the fifth heat exchanger, where it fully exchanges heat with the low-temperature hydrogen, and then enters the cold water tank for storage.

[0019] S5. Simultaneously with the above S3 process, the hot water after being heated by the flue gas heat exchanger is supplied to the fourth heat exchanger through the first circulation pump, releasing heat to the hydrogen. The water after heat exchange returns to the flue gas heat exchanger. By controlling the speed of the first circulation pump, the circulation flow rate is controlled, thereby controlling the temperature of the hydrogen entering the mixing combustion chamber, so as to increase or decrease the power generation power of the flue gas turbine and the steam turbine.

[0020] S6. Simultaneously with the above S3 process, the high-temperature steam generated after passing through the flue gas heat exchanger enters the steam turbine, expands and does work, and the exhaust steam enters the condenser to condense into water. Then, the condensate is pumped into the flue gas heat exchanger by the second circulation pump.

[0021] S7. Simultaneously with the above S3 process, the third circulation pump pumps the water condensed by the cooling tower into the condenser to exchange heat with the exhaust steam of the above S6 process, and the heated water returns to the cooling tower.

[0022] S8. When the unit needs to operate at peak speed in an emergency, close the first shut-off valve, the third shut-off valve, and the fourth shut-off valve, and open the second shut-off valve. At this time, the air that has been pressurized by the first air compressor will no longer be stored. It will bypass the gas storage tank and directly enter the mixing combustion chamber to mix and burn with hydrogen. The unit will enter a gas turbine combined cycle operation mode. At this time, steps S5 to S7 will be performed simultaneously.

[0023] A further improvement of the technical solution of the present invention is that the medium pressure after the first air compressor is 1.1 times the inlet pressure of the flue gas turbine.

[0024] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows:

[0025] This invention, by setting up a compressed air energy storage system and method with hydrogen-assisted combustion, significantly reduces the flow rate of compressed air, lowers the parameters of the gas storage tank, improves the cycle efficiency of long-term energy storage, and makes the system more flexible and adaptable to the requirements of new power systems compared to non-assisted combustion systems.

[0026] This invention enables the unit to switch from pure compression operation to a combined cycle operation mode that can be quickly switched according to the dispatching instructions of the external power grid load by setting a switching valve.

[0027] This invention utilizes a fifth heat exchanger to heat the low-temperature hydrogen from the storage tank, thereby achieving efficient energy utilization. This heat is not fully utilized by the compression heat of conventional non-combustion compressed air energy storage systems.

[0028] This invention utilizes a performance heating module to further increase the temperature of hydrogen, thereby improving turbine output and efficiency. This invention is suitable for large-scale, high-capacity compressed air energy storage. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a hydrogen-assisted combustion compressed air energy storage system according to the present invention.

[0030] The components are: 1. First air compressor, 2. Second air compressor, 3. First heat exchanger, 4. Second heat exchanger, 5. Air storage tank, 6. Hot water tank, 7. Cold water tank, 8. Hot water pump, 9. Cold water pump, 10. Third heat exchanger, 11. Mixing combustion chamber, 12. Fourth heat exchanger, 13. Fifth heat exchanger, 14. Flue gas turbine, 15. Flue gas heat exchanger, 16. Steam turbine, 17. Condenser, 18. Second circulating pump, 19. First circulating pump, 20. Cooling tower, 21. Third circulating pump, 31. First shut-off valve, 32. Second shut-off valve, 33. Third shut-off valve, 34. Fourth shut-off valve. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to embodiments:

[0032] like Figure 1 As shown, a hydrogen-assisted compressed air energy storage system includes a compression module, an expansion power generation module, a heat storage module, a heat release module, a performance heating module, a steam-water thermodynamic circulation module, and a cooling module. The compression module includes a first air compressor 1, a first heat exchanger 3, a second air compressor 2, and a second heat exchanger 4 connected in series. The expansion power generation module includes a gas storage tank 5, a third heat exchanger 10, a mixing combustion chamber 11, a flue gas turbine 14, and a flue gas heat exchanger 15 connected in series. The gas storage tank 5 is connected to the second heat exchanger 4. The heat storage module includes a cold water tank connected in series. 7. Cold water pump 9, first heat exchanger 3, second heat exchanger 4 and hot water tank 6. The heat release module includes hot water tank 6, hot water pump 8, third heat exchanger 10, fifth heat exchanger 13 and cold water tank 7. The performance heating module includes flue gas heat exchanger 15, first circulation pump 19 and fourth heat exchanger 12 connected in a ring. That is, flue gas heat exchanger 15, first circulation pump 19 and fourth heat exchanger 12 form a circulation loop. Flue gas heat exchanger 15 is connected to first circulation pump 19, first circulation pump 19 is connected to fourth heat exchanger 12 and fourth heat exchanger 12 is connected to flue gas heat exchanger 15.

[0033] The steam-water thermal circulation module includes a flue gas heat exchanger 15, a steam turbine 16, a condenser 17, and a second circulation pump 18 connected in a ring. That is, the flue gas heat exchanger 15, steam turbine 16, condenser 17, and second circulation pump 18 form a circulation loop. The flue gas heat exchanger 15 is sequentially connected to the steam turbine 16, condenser 17, and second circulation pump 18, and the second circulation pump 18 is connected to the flue gas heat exchanger 15. The multi-stage heat exchange between the flue gas heat exchanger 15 and steam and water in this application allows for the cascaded utilization of flue gas heat, maximizing heat recovery.

[0034] The cooling module includes a condenser 17, a cooling tower 20, and a third circulation pump 21 connected in a ring. Similarly, the condenser 17, the cooling tower 20, and the third circulation pump 21 form a circulation loop.

[0035] The compression module is equipped with a first shut-off valve 31 and a third shut-off valve 33 on the connecting pipes between the first air compressor 1 and the first heat exchanger 3, and on the connecting pipes between the second air compressor 2 and the gas storage tank 5, respectively. The first air compressor 1 and the third heat exchanger 10 are connected by a pipe, which is equipped with a second shut-off valve 32. A pipeline leading to the expansion power generation module is installed after the first air compressor 1, bypassing the gas storage tank 5. This allows for a rapid change in operating mode to meet the requirements of flexible operation when the unit needs to operate at peak demand.

[0036] The medium pressure after the first air compressor (1) is 1.1 times the inlet pressure of the flue gas turbine (14).

[0037] The hydrogen source is connected to the fifth heat exchanger 13, which is then connected in sequence to the fourth heat exchanger 12 and the mixing combustion chamber 11. The hydrogen fully absorbs the heat stored during the air compression stage, and the water temperature can be reduced to the temperature of the cold water tank, avoiding heat loss. The hydrogen source can be a hydrogen storage tank. The hydrogen is heated by passing through two stages of heat exchangers before entering the mixing combustion chamber 11, improving the turbine output and efficiency during the expansion stage.

[0038] A fourth shut-off valve 34 is installed on the connecting pipe between the gas storage tank 5 and the third heat exchanger 10 in the expansion power generation module. The flue gas turbine 14 drives the connected generator, and the steam turbine 16 of the steam-water thermal circulation module is connected to the generator.

[0039] This application includes a performance heating module that is interlocked with the turbine output, allowing for effective adjustment of the turbine output by controlling the pump's operation.

[0040] A compressed air energy storage system for hydrogen combustion includes a compression module for compressing and storing air, an expansion power generation module for releasing the compressed air into a turbine for expansion and work, a heat storage module for absorbing and storing the heat generated during air compression, a heat release module for releasing the stored heat to the air and hydrogen, a performance heater module for heating the hydrogen, and a steam-water thermal circulation module for absorbing heat from flue gas for further expansion and work.

[0041] A method for storing compressed air with hydrogen combustion, comprising the following arrangement:

[0042] S1. During periods of low electrical load, the air temperature rises to approximately 300°C after being compressed by the first air compressor 1. At this time, the first shut-off valve 31 and the third shut-off valve 33 are opened, while the second shut-off valve 32 and the fourth shut-off valve 34 are closed. The high-temperature air decreases in temperature after passing through the first heat exchanger 3, then increases in temperature after being compressed by the second air compressor 2, and decreases in temperature after entering the second heat exchanger 4, finally being stored in the air storage tank 5.

[0043] S2. Simultaneously with the above S1 process, the cold water pump 9 pressurizes the water in the cold water tank 7, and then divides it into two paths, which enter the first heat exchanger 3 and the second heat exchanger 4 respectively, absorbing the temperature released by the high-temperature air during S1. After the water is heated and becomes high-temperature hot water, it is stored in the hot water tank 6.

[0044] S3. During peak electrical load, the fourth shut-off valve 34 is opened and the third shut-off valve 33 is closed. At this time, the high-pressure low-temperature air in the gas storage tank 5 first absorbs heat and heats up through the third heat exchanger 10, and then enters the mixing combustion chamber 11. It mixes and burns with the hydrogen that has been heated by passing through the fifth heat exchanger 13 and the fourth heat exchanger 12, producing high-temperature flue gas of about 600°C. The flue gas enters the flue gas turbine 14 to expand and do work, and then enters the flue gas heat exchanger 15 to release heat and become low-temperature flue gas discharged into the atmosphere.

[0045] S4. Simultaneously with the process described in S3, the hot water pump 8 pressurizes the water in the hot water tank 6 and sends it into the third heat exchanger 10, where it releases heat to the low-temperature air coming out of the gas storage tank 5. Due to the heat exchange end temperature difference, the water temperature after heat exchange is higher than that in the cold water tank 7. Therefore, the water after heat exchange enters the fifth heat exchanger 13, where it undergoes sufficient heat exchange with the low-temperature hydrogen from the hydrogen storage tank, and then enters the cold water tank 7 for storage.

[0046] S5. Simultaneously with the above-mentioned S3 process, the hot water, after absorbing heat in the flue gas heat exchanger 15, is supplied to the fourth heat exchanger 12 via the first circulation pump 19, releasing heat to the hydrogen and improving the output and efficiency of the flue gas turbine 14. The heat-exchanged water returns to the flue gas heat exchanger 15. The power generation settings of the first circulation pump 19 are interlocked with those of the flue gas turbine 14 and the steam turbine 16. By controlling the rotational speed of the first circulation pump 19, the circulation flow rate is controlled, thereby controlling the temperature of the hydrogen entering the mixing combustion chamber 11, so as to increase or decrease the power generation of the flue gas turbine 14 and the steam turbine 16.

[0047] S6. Simultaneously with the above S3 process, the high-temperature steam generated after passing through the flue gas heat exchanger 15 enters the steam turbine 16, expands and does work, and the exhaust steam enters the condenser 17 and condenses into water. Then, the condensate is pumped into the flue gas heat exchanger 15 through the second circulation pump 18.

[0048] S7. Simultaneously with the above S3 process, the third circulation pump 21 pumps the water condensed by the cooling tower 20 into the condenser 17 to exchange heat with the exhaust steam of the above S6 process, and the heated water returns to the cooling tower 20.

[0049] S8. When the unit needs to operate at peak capacity urgently, close the first shut-off valve 31, the third shut-off valve 33, and the fourth shut-off valve 34, and open the second shut-off valve 32. At this time, the air pressurized by the first air compressor 1 is no longer stored, bypasses the gas storage tank 5, and directly enters the mixing combustion chamber 11 to mix and burn with hydrogen. The unit enters a gas turbine combined cycle operation mode. At this time, steps S5 to S7 are performed simultaneously.

Claims

1. A compressed air energy storage system for hydrogen-assisted combustion, characterized in that: The system includes a compression module, an expansion power generation module, a heat storage module, a heat release module, a performance heating module, a steam-water thermodynamic circulation module, and a cooling module. The compression module includes a first air compressor (1), a first heat exchanger (3), a second air compressor (2), and a second heat exchanger (4) connected in series. The expansion power generation module includes a gas storage tank (5), a third heat exchanger (10), a mixing combustion chamber (11), a flue gas turbine (14), and a flue gas heat exchanger (15) connected in series. The gas storage tank (5) is connected to the second heat exchanger (4). The heat storage module includes a cold water tank (7), and a cold water pump (9) is connected to the cold water tank (7). Two branches are branched off from the cold water pump (9). One branch leads to the first heat exchanger (3), and the other branch leads to the second heat exchanger (4). The two branches are then connected to the hot water tank (6). The heat release module includes the hot water tank (6), the hot water pump (8), the third heat exchanger (10), the fifth heat exchanger (13), and the cold water tank (7). The performance heating module includes a flue gas heat exchanger (15), a first circulation pump (19), and a fourth heat exchanger (12) connected in a ring. The steam-water thermal circulation module includes a flue gas heat exchanger (15), a steam turbine (16), a condenser (17), and a second circulation pump (18) connected in a ring. The cooling module includes a condenser (17) and a cooling tower (2) connected in a ring. 0) and the third circulation pump (21); the compression module is equipped with a first shut-off valve (31) and a third shut-off valve (33) on the connecting pipes of the first air compressor (1) and the first heat exchanger (3) and the connecting pipes of the second air compressor (2) and the gas storage tank (5); the first air compressor (1) and the third heat exchanger (10) are connected by a pipe, and a second shut-off valve (32) is provided on the pipe; the hydrogen source is connected to the fifth heat exchanger (13), and the fifth heat exchanger (13) is connected to the fourth heat exchanger (12) and the mixing combustion chamber (11) in sequence; the connecting pipes of the gas storage tank (5) and the third heat exchanger (10) in the expansion power generation module A fourth shut-off door (34) is installed on the pipeline. The flue gas turbine (14) drives the generator. The steam turbine (16) of the steam-water thermal circulation module is connected to the generator. The power generation of the first circulation pump (19) is interlocked with that of the flue gas turbine (14) and the steam turbine (16). The compression module is used to compress and store air. The expansion power generation module is used to release the compressed air into the turbine to expand and do work. The heat storage module is used to absorb and store the heat generated during the air compression process. The heat release module is used to release the stored heat to the air and hydrogen. The performance heating module is used to heat the hydrogen. The steam-water thermal circulation module is used to absorb the heat of the flue gas and expand to do work.

2. A compressed air energy storage method for hydrogen afterburning applied to the energy storage system as described in claim 1, characterized in that... The following arrangements are included: S1. During the low-load period, the temperature of the atmosphere rises after being compressed by the first air compressor (1), and the first shut-off valve (31) and the third shut-off valve (33) are opened, while the second shut-off valve (32) and the fourth shut-off valve (34) are closed. The temperature of the high-temperature air decreases after passing through the first heat exchanger (3), and the temperature rises after being compressed by the second air compressor (2). The temperature decreases after entering the second heat exchanger (4), and the air is finally stored in the gas storage tank (5). S2. During the above S1 process, the cold water pump (9) pressurizes the water in the cold water tank (7), and then divides it into two paths, which enter the first heat exchanger (3) and the second heat exchanger (4) respectively, absorbing the temperature released by the high temperature air during S1 process. The water is heated and becomes high temperature hot water, which is then stored in the hot water tank (6). S3. During the peak electrical load phase, the fourth shut-off valve (34) is opened and the third shut-off valve (33) is closed. At this time, the high-pressure low-temperature air in the gas storage tank (5) first absorbs heat and heats up through the third heat exchanger (10), and then enters the mixing combustion chamber (11) to mix and burn with the hydrogen that has been heated by passing through the fifth heat exchanger (13) and the fourth heat exchanger (12). The high-temperature flue gas produced enters the flue gas turbine (14) to expand and do work, and then enters the flue gas heat exchanger (15) to release heat and become low-temperature flue gas discharged into the atmosphere. S4. Simultaneously with the above S3 process, the hot water pump (8) pressurizes the water in the hot water tank (6) and enters the third heat exchanger (10), releasing heat to the low-temperature air coming out of the gas storage tank (5). The water after heat exchange enters the fifth heat exchanger (13) and fully exchanges heat with the low-temperature hydrogen, and then enters the cold water tank (7) for storage. S5. Simultaneously with the above S3 process, the hot water after being heated by the flue gas heat exchanger (15) is supplied to the fourth heat exchanger (12) through the first circulation pump (19) to release heat to hydrogen. The water after heat exchange returns to the flue gas heat exchanger (15). By controlling the speed of the first circulation pump (19), the circulation flow rate is controlled, thereby controlling the temperature of hydrogen entering the mixing combustion chamber (11) to increase or decrease the power generation of the flue gas turbine (14) and the steam turbine (16). S6. Simultaneously with the above S3 process, the high-temperature steam generated after passing through the flue gas heat exchanger (15) enters the steam turbine (16), expands and does work, and the exhaust steam enters the condenser (17) to condense into water. Then, the condensate is pumped into the flue gas heat exchanger (15) through the second circulation pump (18). S7. Simultaneously with the above S3 process, the third circulation pump (21) pumps the water condensed by the cooling tower (20) into the condenser (17) to exchange heat with the exhaust steam of the above S6 process, and the heated water returns to the cooling tower (20). S8. When the unit needs to run at peak speed in an emergency, close the first shut-off valve (31), the third shut-off valve (33) and the fourth shut-off valve (34), and open the second shut-off valve (32). At this time, the air that has been pressurized by the first air compressor (1) will no longer be stored. It will bypass the gas storage tank (5) and directly enter the mixing combustion chamber (11) to mix and burn with hydrogen. The unit will enter a gas turbine combined cycle operation mode. At this time, steps S5 to S7 will be performed simultaneously.

3. The compressed air energy storage method for hydrogen afterburning according to claim 2, characterized in that: The medium pressure after the first air compressor (1) is 1.1 times the inlet pressure of the flue gas turbine (14).

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