Liquid air energy storage system thermoelectrically coupled with thermal power generating unit

Abstract

The utility model discloses a liquid air energy storage system in thermoelectric coupling with a thermal power generating unit, which comprises an air compression and liquefaction subsystem, a liquid air expansion power generation subsystem and a cold and hot circulation subsystem which are connected with an original thermal power generation subsystem, the liquid air expansion power generation subsystem is connected with the air compression and liquefaction subsystem and the cold and hot circulation subsystem. The hot and cold circulation subsystem comprises a high-temperature compression heat storage module connected with the air compression and liquefaction subsystem, the liquid air expansion power generation subsystem and the thermal power generation subsystem, and a low-temperature compression heat coupling heat regeneration system module connected with the air compression and liquefaction subsystem and the thermal power generation subsystem; the cold storage module is respectively connected with the air compression and liquefaction subsystem and the liquid air expansion power generation subsystem; and the industrial steam high-temperature heat storage module is respectively connected with the thermal power generation subsystem and the liquid air expansion power generation subsystem. The device has small influence on the original thermal power generating unit, and is flexible in operation and high in energy utilization efficiency.

Description

Technical Field

[0001] The utility model relates to the technical fields of energy storage and thermal power generation, and particularly relates to a liquid air energy storage system coupled with a thermal power unit for thermoelectricity. Background Art

[0002] In recent years, the proportion of new energy sources such as wind power and photovoltaic power in China's energy structure has increased rapidly. By 2025, the proportion of non-fossil energy consumption will reach about 20%. Due to the intermittent output of new energy power generation, in order to ensure the safe grid connection of new energy and improve the comprehensive regulation ability of the power system, the state has greatly increased the number of times of coal-fired units participating in peak regulation and the requirements for their quality. As an important flexible peak regulation power source, thermal power units have changed from power quantity guarantee in the past to double guarantee of power and power quantity. One of the current main tasks is to implement flexible transformation on thermal power units with the largest proportion in the existing installed capacity, and improve the deep peak regulation ability and operation flexibility of the units.

[0003] Configuring energy storage is one of the important means to improve the flexibility of thermal power units. Liquid air energy storage is a long-term energy storage technology, which has flexible thermoelectric output characteristics during operation, and has no geographical condition restrictions for site selection, perfectly fitting the current "three-way linkage" of thermal power units. It is one of the best choices for energy storage configuration in thermal power plants. Currently, most of the research on the coupling of thermal power units with liquid air energy storage or compressed air energy storage technology is to drive the compressor by using the high-pressure steam of the thermal power unit. However, from the actual operation of the thermal power unit, the implementation of this technology inevitably transforms the high-temperature and high-pressure steam pipelines (main steam pipeline, reheater steam pipeline, high-pressure cylinder exhaust pipeline, feed water pipeline, etc.) of the thermal power unit, involving a large range of modification of the unit body and great implementation difficulty, which restricts the coupling application of liquid air energy storage technology and thermal power units. There is a need for a liquid air energy storage system coupled with a thermal power unit that is easy to implement, has little impact on the original system of the unit, and has flexible operation. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a liquid air energy storage system coupled with a thermal power unit for thermoelectricity, so as to solve the problems of complex coupling transformation between the current thermal power unit and liquid air energy storage and great impact on the original operation mode of the thermal power unit, and effectively improve the efficiency of the liquid air energy storage system.

[0005] To solve the above technical problems, the technical solutions adopted by the utility model are as follows.

[0006] A liquid air energy storage system coupled with a thermal power unit for thermoelectricity, comprising an air compression and liquefaction subsystem for consuming the electrical load of the thermal power unit during the energy storage process and converting electrical energy into liquid air for storage, a liquid air expansion power generation subsystem connected to the air compression and liquefaction subsystem for using the liquid air to boost pressure, increase temperature, expand and do work to generate electricity during the energy release process and jointly feeding the generated electricity into the grid with the electricity generated by the thermal power unit, and a cold and heat cycle subsystem respectively connected to the liquid air expansion power generation subsystem and the air compression and liquefaction subsystem for realizing the efficient storage and utilization of cold and heat during the energy storage and release processes; the air compression and liquefaction subsystem, the liquid air expansion power generation subsystem and the cold and heat cycle subsystem are respectively connected to a thermal power generation subsystem of the thermal power unit that is originally used for normal production of electrical energy, industrial steam and civil heating and heat supply;

[0007] The cold and heat cycle subsystem includes a high-temperature compressed heat storage module respectively connected to the air compression and liquefaction subsystem, the liquid air expansion power generation subsystem and the thermal power generation subsystem for storing the high-temperature compressed heat in the air compression and liquefaction subsystem and using the high-temperature compressed heat for power generation in the liquid air expansion power generation subsystem and heat supply to the thermal power generation subsystem, a low-temperature compressed heat coupled regenerative system module respectively connected to the air compression and liquefaction subsystem and the thermal power generation subsystem for directly using the low-temperature compressed heat in the air compression and liquefaction subsystem in the thermal power generation subsystem and simultaneously introducing the condensed water in the thermal power generation subsystem as the cooling working medium for the air compression and liquefaction subsystem, a cold storage module respectively connected to the air compression and liquefaction subsystem and the liquid air expansion power generation subsystem for storing the cold released when the air changes from liquid to gas during the operation of the liquid air expansion power generation subsystem and transferring this part of cold to the air compression and liquefaction subsystem, and an industrial steam high-temperature heat storage module respectively connected to the thermal power generation subsystem and the liquid air expansion power generation subsystem for storing the high-quality sensible heat in the industrial extraction steam of the thermal power generation subsystem and using the high-quality sensible heat for power generation in the liquid air expansion power generation subsystem.

[0008] Preferably, the air compression and liquefaction subsystem includes a first compressor for compressing air and a second compressor connected in series with the first compressor. A first post-cooler for cooling the exhaust gas of the first compressor is arranged between the first compressor and the second compressor. A second post-cooler for cooling the exhaust gas of the second compressor is arranged behind the second compressor. A liquefaction main heat exchanger for cooling the air coming out of the second post-cooler is arranged behind the second post-cooler; a low-temperature throttle valve, a gas-liquid separator and a liquid air storage tank are sequentially arranged behind the liquefaction main heat exchanger, so as to realize that the air cooled by the liquefaction main heat exchanger passes through the low-temperature throttle valve and the gas-liquid separator and is stored in the liquid air storage tank in the form of normal-pressure liquid; the first compressor is connected with a first compressor motor, and the second compressor is connected with a second compressor motor.

[0009] Preferably, the number of compressors in the air compression and liquefaction subsystem includes, but is not limited to, a first compressor and a second compressor.

[0010] Preferably, the liquid air expansion power generation subsystem includes a cryogenic liquid pump, an evaporator, an air-water heater, an air-molten salt heater, an air expander, an air-molten salt reheater, an air expansion generator, and an energy storage system transformer, which are connected in sequence behind the liquid air storage tank, so as to realize that the liquid air in the liquid air storage tank enters the evaporator after being boosted by the cryogenic liquid pump, becomes high-pressure normal-temperature air, and then passes through the air-water heater and the air-molten salt heater in sequence to be heated and enter the air expander to do work and drive the air expansion generator to generate electricity; the power supplies of the first compressor motor and the second compressor motor are both connected from the energy storage system transformer, and the high-voltage side of the energy storage system transformer is also connected to the outlet or bus of the steam turbine generator in the thermal power generation subsystem, so as to realize that the air compression and liquefaction in the energy storage process consumes the electric energy generated by the steam turbine generator in the thermal power generation subsystem, and the electric energy generated by the air expansion generator in the energy release process is incorporated into the energy storage system transformer and jointly feeds the grid with the electric energy generated by the steam turbine generator in the thermal power generation subsystem.

[0011] Preferably, the high-temperature compression heat storage module includes a normal-temperature water tank for storing normal-temperature water and a high-temperature hot water tank for storing high-temperature water coming out of the aftercooler of the first compressor; the water inlet of the high-temperature hot water tank is connected to the hot water outlet of the aftercooler of the first compressor, and the water outlet of the high-temperature hot water tank is connected to the hot water inlet of the air-water heater, so as to realize that the high-temperature water in the high-temperature hot water tank is used to initially heat the air through the air-water heater during the power generation process of the liquid air expansion power generation subsystem; the water inlet of the normal-temperature water tank is connected to the cold water outlet of the air-water heater, and the water outlet of the normal-temperature water tank is connected to the cold water inlet of the aftercooler of the first compressor; the water outlet of the high-temperature hot water tank is also connected to the hot water inlet of the heat supply heat exchanger in the thermal power generation subsystem through a pipeline and a heat supply heat exchanger inlet valve arranged on the pipeline, so as to realize that the high-temperature water in the high-temperature hot water tank jointly supplies heat to the outside through the heat supply heat exchanger and the heat network heater in the thermal power generation subsystem; the cold water outlet of the heat supply heat exchanger is also connected to the water inlet of the normal-temperature water tank through a pipeline and a heat supply heat exchanger outlet valve arranged on the pipeline.

[0012] Preferably, the low-temperature compression heat coupling and regenerative system module realizes the connection of the water outlet of the shaft seal heater in the regenerative unit to the cold water inlet of the aftercooler of the second compressor through a pipeline, and realizes the connection of the hot water outlet of the aftercooler of the second compressor to the inlets of the fifth low-pressure heater and the sixth low-pressure heater located at the last stage in the regenerative unit through a pipeline and valves respectively; the low-temperature compression heat coupling and regenerative system module selects to introduce the condensed water heated up in the aftercooler of the second compressor into the inlet of the fifth low-pressure heater or the inlet of the sixth low-pressure heater according to the different loads of the thermal power generation subsystem.

[0013] Preferably, the cold storage module includes a packed bed for storing cold energy. The packed bed is connected in parallel between the evaporator and the main liquefaction heat exchanger through pipelines. A packed bed inlet control valve and a packed bed outlet control valve for realizing the adjustment of the cold storage and cold release processes are respectively arranged at the inlet and outlet of the packed bed.

[0014] Preferably, the industrial steam high-temperature heat storage module includes a steam-salt heat exchanger that is connected in parallel with the desuperheater in the thermal power generation subsystem and is used to cool the reheated extraction steam to the temperature required by the user and then supply it to the heat user, and a steam-salt heat exchanger inlet valve and a steam-salt heat exchanger outlet valve that are respectively arranged at the steam inlet and steam outlet of the steam-salt heat exchanger; the molten salt inlet of the steam-salt heat exchanger is connected to a low-temperature molten salt tank, and a heat storage molten salt pump for pumping the low-temperature molten salt in the low-temperature molten salt tank into the steam-salt heat exchanger is arranged between the low-temperature molten salt tank and the steam-salt heat exchanger; the molten salt outlet of the steam-salt heat exchanger is connected to a high-temperature molten salt tank, and the bottom outlet of the high-temperature molten salt tank is connected to a heat release molten salt pump that is respectively connected to the molten salt inlets of the air-salt heater and the air-salt reheater and is used to pump the high-temperature molten salt in the high-temperature molten salt tank into the air-salt heater and the air-salt reheater. The molten salt outlets of the air-salt heater and the air-salt reheater are both connected to the top inlet of the low-temperature molten salt tank, so as to realize that the high-temperature molten salt in the high-temperature molten salt tank heats the air through the air-salt heater and the air-salt reheater during the power generation process of the liquid air expansion power generation subsystem and then enters the low-temperature molten salt tank.

[0015] Due to the adoption of the above technical solutions, the technical progress obtained by the present utility model is as follows.

[0016] The present utility model utilizes the electric energy generated by the thermal power unit during the energy storage process, reduces the on-grid power of the thermal power unit, and jointly regulates the peak with the thermal power unit; during the process when the thermal power unit needs to peak, it releases energy and jointly peaks with the thermal power unit, improving the operating flexibility of the thermal power unit. By using the compressed heat with a lower temperature during the compression process to heat the condensate water of the thermal power unit and the compressed heat with a higher temperature to heat the air during the energy release process, the reasonable utilization of the compressed heat is realized. At the same time, by using the existing industrial extraction steam of the thermal power unit, an industrial steam high-temperature heat storage module is added to replace the original desuperheating by spraying water, and the high-quality heat in the industrial extraction steam is stored and used to heat the air at the inlet of the expander during the energy release process, not only recovering the high-quality energy, but also improving the energy utilization efficiency of the system.

[0017] The coupling of the present utility model with the thermal power unit is scientific, reasonable and easy to implement. It reasonably utilizes the high-quality energy of the thermal power unit, and at the same time, the transformation of the original system of the thermal power unit is less, realizing the coupling with the liquid air energy storage thermoelectricity. The combined operation mode of the two is flexible and the energy utilization efficiency is high. Description of the Drawings

[0018] Figure 1 This is a schematic diagram of the system structure of the present utility model.

[0019] Wherein: 1. First compressor, 2. First compressor motor, 3. Second compressor, 4. Second compressor motor, 5. After-cooler of the first compressor, 6. Normal temperature water tank, 7. High temperature hot water tank, 8. After-cooler of the second compressor, 9. Main liquefaction heat exchanger, 10. Low temperature throttle valve, 11. Packed bed, 12. Control valve for the inlet of the packed bed, 13. Control valve for the outlet of the packed bed, 14. Gas-liquid separator, 15. Liquid air storage tank, 16. Low temperature liquid pump, 17. Evaporator, 18. Air-water heater, 19. Air-molten salt heater, 20. Air-molten salt reheater, 21. High temperature molten salt tank, 22. Heat release molten salt pump, 23. Bypass valve for molten salt heat release, 24. Low temperature molten salt tank, 25. Heat storage molten salt pump, 26. Bypass valve for molten salt heat storage, 27. Air expander, 28. Air expansion generator, 29. Inlet valve of the steam-molten salt heat exchanger, 30. Steam-molten salt heat exchanger, 31. Outlet valve of the steam-molten salt heat exchanger, 32. Spray desuperheater, 33. Deaerator, 34. Feed water pump, 35. No. 3 high pressure heater, 36. No. 2 high pressure heater, 37. No. 1 high pressure heater, 38. Boiler, 39. High pressure cylinder of the steam turbine, 40. Intermediate pressure cylinder of the steam turbine, 41. Low pressure cylinder of the steam turbine, 42. Steam turbine generator, 43. Transformer of the energy storage system, 44. Condenser, 45. Shaft seal heater, 46. No. 8 low pressure heater, 47. No. 7 low pressure heater, 48. No. 6 low pressure heater, 49. No. 5 low pressure heater, 50. Outlet valve of the heat supply heat exchanger, 51. Inlet valve of the heat supply heat exchanger, 52. Heat supply heat exchanger, 53. Heat network heater. Detailed Embodiments

[0020] The present utility model will be further described in detail below in conjunction with the drawings and specific embodiments.

[0021] A liquid air energy storage system thermally coupled with a thermal power unit, combined with Figure 1As shown in the figure, it includes an air compression and liquefaction subsystem, a liquid air expansion power generation subsystem, and a cold and heat cycle subsystem. The air compression and liquefaction subsystem, the liquid air expansion power generation subsystem, and the cold and heat cycle subsystem are all connected to the original thermal power generation subsystem of the thermal power unit. Among them, the thermal power generation subsystem is used for normal production of electric energy, industrial steam, and civil heating; the air compression and liquefaction subsystem is used to consume the electric load of the thermal power unit during the energy storage process, convert electric energy into liquid air for storage, so as to reduce the grid-connected power of the unit during the operation process by consuming the electric energy generated by the thermal power generation subsystem, and cooperate with the thermal power unit for deep peak shaving; the liquid air expansion power generation subsystem is connected to the air compression and liquefaction subsystem. The liquid air expansion power generation subsystem is used to generate electricity by using the liquid air to boost pressure, increase temperature, and expand to do work during the energy release process, and jointly grid-connect the electricity generated by the thermal power unit, so as to cooperate with the thermal power unit for peak shaving during the operation process; the cold and heat cycle subsystem is respectively connected to the air compression and liquefaction subsystem and the liquid air expansion power generation subsystem. The cold and heat cycle subsystem is used to realize the efficient storage and utilization of cold and heat during the energy storage and release processes.

[0022] The thermal power generation subsystem is a prior art, including a spray desuperheater 32, a deaerator 33, a feed water pump 34, a No. 3 high-pressure heater 35, a No. 2 high-pressure heater 36, a No. 1 high-pressure heater 37, a boiler 38, a high-pressure cylinder 39 of the steam turbine, a medium-pressure cylinder 40 of the steam turbine, a low-pressure cylinder 41 of the steam turbine, a turbogenerator 42, a condenser 44, a shaft seal heater 45, an No. 8 low-pressure heater 46, a No. 7 low-pressure heater 47, a No. 6 low-pressure heater 48, a No. 5 low-pressure heater 49, a heat supply heat exchanger 52, and a heat network heater 53. The connection relationship of each component is as Figure 1 shown in the figure and will not be elaborated here. Among them, the shaft seal heater 45, the No. 8 low-pressure heater 46, the No. 7 low-pressure heater 47, the No. 6 low-pressure heater 48, and the No. 5 low-pressure heater 49 are connected in sequence to form a regenerative unit in the thermal power generation subsystem; the spray desuperheater 32 is used to cool the reheated extraction steam to the user demand temperature and then supply it to the heat user; the turbogenerator 42 is used for power generation.

[0023] The air compression and liquefaction subsystem includes a first compressor 1 and a second compressor 3. The first compressor 1 and the second compressor 3 are connected in series to compress air. The first compressor 1 is connected to a first compressor motor 2, and the second compressor 3 is connected to a second compressor motor 4. A first post-compressor cooler 5 is provided between the first compressor 1 and the second compressor 3, and the first post-compressor cooler 5 is used to cool the exhaust gas of the first compressor 1. A second post-compressor cooler 8 is provided behind the second compressor 3, and the second post-compressor cooler 8 is used to cool the exhaust gas of the second compressor 3. A main liquefaction heat exchanger 9 is provided behind the second post-compressor cooler 8. The main liquefaction heat exchanger 9 is used to cool the air coming out of the second post-compressor cooler 8. Behind the main liquefaction heat exchanger 9, a low-temperature throttle valve 10, a gas-liquid separator 14, and a liquid air storage tank 15 are arranged in sequence, so that the air cooled by the main liquefaction heat exchanger 9 passes through the low-temperature throttle valve 10 and the gas-liquid separator 14 and is stored in the liquid air storage tank 15 in the form of normal-pressure liquid.

[0024] The number of compressors in the air compression and liquefaction subsystem includes, but is not limited to, the first compressor 1 and the second compressor 3. The exhaust gas temperature of each compressor is determined according to specific process parameters. In this embodiment, the exhaust gas temperature of the first compressor 1 is higher than that of the second compressor 3 as an example for illustration, and the number and connection mode of the compressors are not limited to the manner mentioned in this embodiment.

[0025] The liquid air expansion power generation subsystem includes a low-temperature liquid pump 16, an evaporator 17, an air-water heater 18, an air-molten salt heater 19, an air expander 27, an air-molten salt reheater 20, an air expansion generator 28, and an energy storage system transformer 43, which are connected in sequence behind the liquid air storage tank 15. Thus, the liquid air in the liquid air storage tank 15 is boosted by the low-temperature liquid pump 16 and enters the evaporator 17 to become high-pressure normal-temperature air, and then passes through the air-water heater 18 and the air-molten salt heater 19 in sequence and is heated to enter the air expander 27 to do work. The air expander 27 drives the air expansion generator 28 to generate electricity. The electric energy consumed by the first compressor motor 2 and the second compressor motor 4 comes from the electric energy generated by the thermal power generation subsystem. Correspondingly, the power supplies of the first compressor motor 2 and the second compressor motor 4 are both connected to the energy storage system transformer 43. The high-voltage side of the energy storage system transformer 43 is also connected to the outlet or busbar of the steam turbine generator 42 in the thermal power generation subsystem, so as to realize that the air compression and liquefaction in the energy storage process consumes the electric energy generated by the steam turbine generator in the thermal power generation subsystem, and the electric energy generated by the air expansion generator 28 in the energy release process is incorporated into the energy storage system transformer 43 and is jointly put on the grid with the power generation of the steam turbine generator 42 in the thermal power generation subsystem.

[0026] The hot and cold cycle subsystem includes a high-temperature compression heat storage module, a low-temperature compression heat-coupled regenerative system module, a cold storage module, and an industrial steam high-temperature heat storage module.

[0027] The high-temperature compression heat storage module is used to store the high-temperature compression heat in the air compression and liquefaction subsystem and use the high-temperature compression heat for power generation in the liquid air expansion power generation subsystem and heat supply in the thermal power generation subsystem. The high-temperature compression heat is the higher-temperature exhaust gas from the first compressor 1 and the second compressor 3. Specifically, the high-temperature compression heat storage module includes a normal-temperature water tank 6 and a high-temperature hot water tank 7. Among them, the normal-temperature water tank 6 is used to store normal-temperature water, and the high-temperature hot water tank 7 is used to store the high-temperature water coming out of the first compressor aftercooler 5. The water inlet of the high-temperature hot water tank 7 is connected to the hot water outlet of the first compressor aftercooler 5, and the water outlet of the high-temperature hot water tank 7 is connected to the hot water inlet of the air-water heater 18; the water inlet of the normal-temperature water tank 6 is connected to the cold water outlet of the air-water heater 18, and the water outlet of the normal-temperature water tank 6 is connected to the cold water inlet of the first compressor aftercooler 5. During the air compression and liquefaction process, the cooling water from the normal-temperature water tank 6 enters the first compressor aftercooler 5 to cool the exhaust gas of the first compressor 1, and the cooling water with increased temperature enters the high-temperature hot water tank 7 for storage. The stored hot water conducts primary heating on the air through the air-water heater 18 during the power generation process of the liquid air expansion power generation subsystem.

[0028] The water outlet of the high-temperature hot water tank 7 is also connected through a pipeline and a heat supply heat exchanger inlet valve 51 provided on the pipeline to the hot water inlet of the heat supply heat exchanger 52 in the thermal power generation subsystem, so as to realize the combined external heat supply of the high-temperature water in the high-temperature hot water tank 7 and the heat network heater 53 in the thermal power generation subsystem through the heat supply heat exchanger 52; the cold water outlet of the heat supply heat exchanger 52 is also connected through a pipeline and a heat supply heat exchanger outlet valve 50 provided on the pipeline to the water inlet of the normal-temperature water tank 6, so as to return the cooled water to the normal-temperature water tank 6.

[0029] The low-temperature compression heat-coupled regenerative system module is used to directly utilize the low-temperature compression heat in the air compression and liquefaction subsystem for the regenerative unit in the thermal power generation subsystem, and at the same time introduce the condensed water in the thermal power generation subsystem as the cooling working medium for the air compression and liquefaction subsystem. The low-temperature compression heat is the lower-temperature exhaust gas from the first compressor 1 and the second compressor 3. Specifically, the low-temperature compression heat-coupled regenerative system module connects the water outlet of the shaft seal heater 45 in the regenerative unit to the cold water inlet of the aftercooler 8 of the second compressor through pipelines. The low-temperature compression heat-coupled regenerative system module also connects the hot water outlet of the aftercooler 8 of the second compressor to the inlets of the fifth low-pressure heater 49 and the sixth low-pressure heater 48 at the last stage in the regenerative unit through pipelines and valves respectively, so as to directly utilize the low-temperature compression heat in the air compression and liquefaction subsystem for the regenerative unit in the thermal power generation subsystem, and at the same time introduce the condensed water in the thermal power generation subsystem as the cooling working medium for the air compression and liquefaction subsystem. And the low-temperature compression heat-coupled regenerative system module selects to introduce the condensed water heated up in the aftercooler 8 of the second compressor into the inlet of the fifth low-pressure heater 49 or the inlet of the sixth low-pressure heater 48 according to the different loads of the thermal power generation subsystem.

[0030] The cold storage module is used to store the cold energy released when liquid air changes from liquid to gas in the evaporator 17 during the operation of the liquid air expansion power generation subsystem, and transfer this part of cold energy to the liquefaction main heat exchanger 9 during the operation of the air compression and liquefaction subsystem. Specifically, the cold storage module includes a packed bed 11, which is used to store cold energy. The packed bed 11 is connected in parallel between the evaporator 17 and the liquefaction main heat exchanger 9 through pipelines. The cold energy released when the air in the evaporator 17 changes from liquid to gas is stored by the packed bed 11, and the cold energy stored by the packed bed 11 is used for the liquefaction main heat exchanger 9. At the same time, the cold energy of the liquefaction main heat exchanger 9 also comes from the cold energy provided by the low-temperature gas flowing back from the gas-liquid separator 14. The inlet control valve 12 and the outlet control valve 13 of the packed bed are respectively arranged corresponding to the top inlet and the bottom outlet of the packed bed 11. The inlet control valve 12 and the outlet control valve 13 of the packed bed are used to adjust the cold storage and cold release processes.

[0031] The corresponding cold storage process cycle is as follows: The packed bed 11 has released cold energy, and the upper part is normal-temperature air. The direction of the circulating air flowing in the packed bed 11 is from the packed bed outlet control valve 13 to the packed bed inlet control valve 12. The normal-temperature air flowing out of the packed bed 11 flows into the evaporator 17 after passing through the packed bed inlet control valve 12 and the pipeline. During this process, the normal-temperature air absorbs cold energy and its temperature drops to become low-temperature air, which flows out through the outlet of the evaporator 17, passes through the pipeline and the packed bed outlet control valve 13, and enters the bottom of the packed bed 11. The low-temperature air gradually transfers the cold energy to the packing medium, and its temperature gradually becomes normal temperature until the upper end outlet of the packed bed, completing a cold storage cycle. After the system stops running, the packed bed inlet control valve 12 and the packed bed outlet control valve 13 are closed.

[0032] The corresponding cold release process cycle is as follows: The cold energy of the packed bed 11 is already full. The direction of the circulating air flowing in the packed bed 11 is from the packed bed inlet control valve 12 to the packed bed outlet control valve 13, and both valves are in the open state. The low-temperature air flowing out of the packed bed 11 flows into the main liquefaction heat exchanger 9 after passing through the packed bed outlet control valve 13 and the pipeline. During this process, the low-temperature air releases the cold energy to the normal-temperature air entering the main liquefaction heat exchanger 9. After releasing the cold energy, the temperature of the low-temperature air rises and becomes normal-temperature air, which flows out through the outlet of the main liquefaction heat exchanger 9, passes through the pipeline and the packed bed inlet control valve 12, and enters the upper part of the packed bed 11. The normal-temperature air continues to absorb the cold energy of the internal packing medium, and its temperature gradually becomes low temperature until the lower end outlet of the packed bed 11, completing a cold release cycle. After the system stops running, the packed bed inlet control valve 12 and the packed bed outlet control valve 13 are closed.

[0033] The industrial steam high-temperature heat storage module is designed based on the operating characteristics of continuous operation of industrial steam and spray desuperheating. The industrial steam high-temperature heat storage module is used to store the high-quality sensible heat in the industrial extraction steam of the thermal power generation subsystem and use the high-quality sensible heat for power generation in the liquid air expansion power generation subsystem, specifically for heating the inlet and inter-stage air of the expander during the power generation process of the liquid air expansion power generation subsystem. Specifically, the industrial steam high-temperature heat storage module includes a steam-salt heat exchanger 30. A steam-salt heat exchanger inlet valve 29 and a steam-salt heat exchanger outlet valve 31 are provided in one-to-one correspondence with the steam inlet and steam outlet of the steam-salt heat exchanger 30. The steam-salt heat exchanger 30, the steam-salt heat exchanger inlet valve 29, and the steam-salt heat exchanger outlet valve 31 are connected in parallel with the spray desuperheater 32 in the thermal power generation subsystem. During operation, the reheated extraction steam is cooled to the required temperature by passing through the steam-salt heat exchanger 30 and then supplied to the heat user.

[0034] The molten salt inlet of the steam - molten salt heat exchanger 30 is connected to the low - temperature molten salt tank 24. A heat - storage molten salt pump 25 is arranged between the low - temperature molten salt tank 24 and the steam - molten salt heat exchanger 30. Specifically, the inlet of the heat - storage molten salt pump 25 is connected to the bottom of the low - temperature molten salt tank 24, and the outlet of the heat - storage molten salt pump 25 is connected to the molten salt inlet of the steam - molten salt heat exchanger 30. The heat - storage molten salt pump 25 is used to pump the low - temperature molten salt in the low - temperature molten salt tank 24 into the steam - molten salt heat exchanger 30. The molten salt outlet of the steam - molten salt heat exchanger 30 is connected to the high - temperature molten salt tank 21, and a molten salt heat - storage bypass valve 26 is set to adjust the temperature and flow rate of the molten salt entering the high - temperature molten salt tank 21. At the same time, the bottom outlet of the high - temperature molten salt tank 21 is connected to a heat - releasing molten salt pump 22, specifically connected to the inlet of the heat - releasing molten salt pump 22. The outlet of the heat - releasing molten salt pump 22 is respectively connected to the molten salt inlets of the air - molten salt heater 19 and the air - molten salt reheater 20 through pipelines. The molten salt outlets of the air - molten salt heater 19 and the air - molten salt reheater 20 are both connected to the top inlet of the low - temperature molten salt tank 24. The heat - releasing molten salt pump 22 is used to pump the high - temperature molten salt in the high - temperature molten salt tank 21 into the air - molten salt heater 19 and the air - molten salt reheater 20, so as to realize that the high - temperature molten salt in the high - temperature molten salt tank 21 heats the air through the air - molten salt heater 19 and the air - molten salt reheater 20 during the power generation process of the liquid air expansion power generation subsystem and then enters the low - temperature molten salt tank 24. At the same time, a molten salt heat - release bypass valve 23 is set to adjust the temperature and flow rate of the molten salt entering the low - temperature molten salt tank 24.

[0035] The corresponding operation mode of the heat - storage process:

[0036] The steam - molten salt heat exchanger inlet valve 29 and the steam - molten salt heat exchanger outlet valve 31 of the steam - molten salt heat exchanger 30 are opened. At the same time, the molten salt from the low - temperature molten salt tank 24 enters the steam - molten salt heat exchanger 30 through the heat - storage molten salt pump 25 to exchange heat with the industrial extraction steam. The molten salt absorbs a part of the sensible heat of the industrial extraction steam. After the industrial extraction steam meets the requirements of the heat user, it is supplied to the heat user. After the temperature of the molten salt rises, it enters the high - temperature molten salt tank 21 for storage. It should be noted that the size of the molten salt flow rate during the heat - storage process is determined by the demand of the industrial steam user. The continuous operation of the heat - storage process does not conflict with the heat - release process and operates according to the user's demand. When the heat - storage amount meets the heat required by the liquid air expansion power generation subsystem, the operation stops. The steam - molten salt heat exchanger inlet valve 29 and the steam - molten salt heat exchanger outlet valve 31 are closed, and the industrial steam supply is switched to the original spray desuperheating mode for operation.

[0037] The corresponding high - temperature heat - release cycle is:

[0038] The high - temperature heat - release cycle corresponds to the liquid air expansion power generation process. The high - temperature molten salt from the high - temperature molten salt tank 21 enters the air - molten salt heater 19 and the air - molten salt reheater 20 respectively after passing through the heat - releasing molten salt pump 22, heats the air to the set temperature and then returns to the low - temperature molten salt tank 24 to complete a heat - release cycle.

[0039] When the utility model is in use, it consumes the electric energy generated by the thermal power unit during the energy storage process, reduces the grid-connected power of the thermal power unit, and jointly participates in peak regulation with the thermal power unit; during the process when the thermal power unit needs to reach the peak load, it releases energy to jointly peak with the thermal power unit, improving the operation flexibility of the thermal power unit. By using the relatively low-temperature compression heat in the compression process to heat the condensate water of the thermal power unit and the relatively high-temperature compression heat to heat the air in the energy release process, the rational utilization of the compression heat is realized. At the same time, by using the existing industrial extraction steam of the thermal power unit, an industrial steam high-temperature energy storage module is added to replace the original spray desuperheating, storing the high-quality heat in the industrial extraction steam for heating the air at the inlet of the expander in the energy release process, not only recovering the high-quality energy but also improving the energy utilization efficiency of the system.

[0040] The coupling of the utility model with the thermal power unit is scientific, reasonable and easy to implement. It rationally utilizes the high-quality energy of the thermal power unit, and at the same time, the transformation of the original system of the thermal power unit is less. It realizes the coupling with the liquid air energy storage thermoelectricity, and the combined operation mode of the two with the thermal power unit is flexible and the energy utilization efficiency is high.

Claims

1. A liquid air energy storage system coupled with a thermal power unit for thermal power, comprising an air compression and liquefaction subsystem for consuming the electrical load of the thermal power unit during the energy storage process and converting electrical energy into liquid air for storage, a liquid air expansion power generation subsystem connected to the air compression and liquefaction subsystem for using the liquid air to boost pressure, increase temperature, expand and do work to generate electricity during the energy release process and jointly feeding the generated electricity into the grid with the thermal power unit, and a heat and cold cycle subsystem connected to the liquid air expansion power generation subsystem and the air compression and liquefaction subsystem respectively for realizing the efficient storage and utilization of cold and heat during the energy storage and energy release processes; the air compression and liquefaction subsystem, the liquid air expansion power generation subsystem and the heat and cold cycle subsystem are also respectively connected to the thermal power generation subsystem of the thermal power unit that is originally used for normal power generation, industrial steam production and civil heating; The heat and cold cycle subsystem includes a high-temperature compressed heat storage module connected to the air compression and liquefaction subsystem, the liquid air expansion power generation subsystem and the thermal power generation subsystem respectively and used for storing the high-temperature compressed heat in the air compression and liquefaction subsystem and using the high-temperature compressed heat for power generation in the liquid air expansion power generation subsystem and heating in the thermal power generation subsystem, a low-temperature compressed heat coupled regenerative system module connected to the air compression and liquefaction subsystem and the thermal power generation subsystem respectively and used for directly using the low-temperature compressed heat in the air compression and liquefaction subsystem in the thermal power generation subsystem and simultaneously introducing the condensate water in the thermal power generation subsystem as the cooling working medium of the air compression and liquefaction subsystem, a cold storage module connected to the air compression and liquefaction subsystem and the liquid air expansion power generation subsystem respectively and used for storing the cold released when the air changes from liquid to gas during the operation of the liquid air expansion power generation subsystem and transferring this part of cold to the air compression and liquefaction subsystem, and an industrial steam high-temperature heat storage module connected to the thermal power generation subsystem and the liquid air expansion power generation subsystem respectively and used for storing the high-quality sensible heat in the industrial extraction steam of the thermal power generation subsystem and using the high-quality sensible heat for power generation in the liquid air expansion power generation subsystem.

2. The liquid air energy storage system thermally coupled with a thermal power unit according to claim 1, wherein: The air compression and liquefaction subsystem includes a first compressor (1) for compressing air and a second compressor (3) connected in series with the first compressor (1). A first post-compressor cooler (5) for cooling the exhaust gas of the first compressor (1) is provided between the first compressor (1) and the second compressor (3). A second post-compressor cooler (8) for cooling the exhaust gas of the second compressor (3) is provided behind the second compressor (3). A main liquefaction heat exchanger (9) for cooling the air coming out of the second post-compressor cooler (8) is provided behind the second post-compressor cooler (8). Behind the main liquefaction heat exchanger (9), a low-temperature throttle valve (10), a gas-liquid separator (14), and a liquid air storage tank (15) are sequentially provided, so that the air cooled by the main liquefaction heat exchanger (9) passes through the low-temperature throttle valve (10) and the gas-liquid separator (14) and is stored in the liquid air storage tank (15) in the form of normal-pressure liquid. The first compressor (1) is connected to a first compressor motor (2), and the second compressor (3) is connected to a second compressor motor (4).

3. A liquid air energy storage system coupled with a thermal power unit for thermoelectric coupling according to claim 2, characterized in that: The number of compressors in the air compression and liquefaction subsystem includes, but is not limited to, the first compressor (1) and the second compressor (3).

4. The liquid air energy storage system coupled with a thermal power unit for thermoelectric coupling according to claim 2, wherein: The liquid air expansion power generation subsystem includes a low-temperature liquid pump (16), an evaporator (17), an air-water heater (18), an air-molten salt heater (19), an air expander (27), an air-molten salt reheater (20), an air expansion generator (28), and an energy storage system transformer (43) connected in sequence behind the liquid air storage tank (15), so that the liquid air in the liquid air storage tank (15) is boosted by the low-temperature liquid pump (16) and enters the evaporator (17) to become high-pressure normal-temperature air, and then passes through the air-water heater (18) and the air-molten salt heater (19) in sequence and is heated to enter the air expander (27) to do work and drive the air expansion generator (28) to generate electricity. The power supplies of the first compressor motor (2) and the second compressor motor (4) are both connected to the energy storage system transformer (43), and the high-voltage side of the energy storage system transformer (43) is also connected to the outlet or bus of the steam turbine generator (42) in the thermal power generation subsystem, so that the electrical energy generated by the steam turbine generator in the thermal power generation subsystem can be consumed by air compression and liquefaction during the energy storage process, and the electrical energy generated by the air expansion generator (28) during the energy release process is incorporated into the energy storage system transformer (43) and is jointly fed into the grid with the power generated by the steam turbine generator (42) in the thermal power generation subsystem.

5. The liquid air energy storage system coupled with a thermal power unit according to claim 4, wherein: The high-temperature compression heat storage module includes a normal-temperature water tank (6) for storing normal-temperature water and a high-temperature hot water tank (7) for storing high-temperature water discharged from the first compressor aftercooler (5); the water inlet of the high-temperature hot water tank (7) is connected to the hot water outlet of the first compressor aftercooler (5), and the water outlet of the high-temperature hot water tank (7) is connected to the hot water inlet of the air-water heater (18), so as to enable the high-temperature water in the high-temperature hot water tank (7) to conduct primary heating on air during the power generation process of the liquid air expansion power generation subsystem through the air-water heater (18); the water inlet of the normal-temperature water tank (6) is connected to the cold water outlet of the air-water heater (18), and the water outlet of the normal-temperature water tank (6) is connected to the cold water inlet of the first compressor aftercooler (5); the water outlet of the high-temperature hot water tank (7) is also connected to the hot water inlet of the heat supply heat exchanger (52) in the thermal power generation subsystem through a pipeline and a heat supply heat exchanger inlet valve (51) provided on the pipeline, so as to enable the high-temperature water in the high-temperature hot water tank (7) to jointly supply heat to the outside through the heat supply heat exchanger (52) and the heat network heater (53) in the thermal power generation subsystem; the cold water outlet of the heat supply heat exchanger (52) is also connected to the water inlet of the normal-temperature water tank (6) through a pipeline and a heat supply heat exchanger outlet valve (50) provided on the pipeline.

6. A liquid air energy storage system coupled with a thermal power unit for thermoelectric coupling according to claim 4, characterized in that: The low-temperature compression heat coupling and regenerative system module is connected to the cold water inlet of the second compressor aftercooler (8) through a pipeline from the water outlet of the shaft seal heater (45) in the regenerative unit, and is respectively connected to the inlets of the fifth low-pressure heater (49) and the sixth low-pressure heater (48) at the last stage in the regenerative unit through a pipeline and a valve from the hot water outlet of the second compressor aftercooler (8); the low-temperature compression heat coupling and regenerative system module selects to introduce the condensed water heated up in the second compressor aftercooler (8) into the inlet of the fifth low-pressure heater (49) or the inlet of the sixth low-pressure heater (48) according to the different loads of the thermal power generation subsystem.

7. A liquid air energy storage system coupled with a thermal power unit for thermoelectric coupling according to claim 4, characterized in that: The cold storage module includes a packed bed (11) for storing cold energy. The packed bed (11) is connected in parallel between the evaporator (17) and the liquefaction main heat exchanger (9) through a pipeline. The inlet and outlet of the packed bed (11) are respectively provided with a packed bed inlet control valve (12) and a packed bed outlet control valve (13) for realizing the adjustment of the cold storage and cold release processes.

8. A liquid air energy storage system coupled with a thermal power unit for thermoelectric coupling according to claim 5, characterized in that: The industrial steam high-temperature heat storage module includes a steam-salt heat exchanger (30) that is connected in parallel with the desuperheater (32) in the thermal power generation subsystem and is used to cool the reheated extraction steam to the temperature required by users and then supply it to the heat users, and a steam-salt heat exchanger inlet valve (29) and a steam-salt heat exchanger outlet valve (31) that are respectively arranged at the steam inlet and the steam outlet of the steam-salt heat exchanger (30); the molten salt inlet of the steam-salt heat exchanger (30) is connected to a low-temperature molten salt tank (24), and a heat storage molten salt pump (25) is arranged between the low-temperature molten salt tank (24) and the steam-salt heat exchanger (30) and is used to pump the low-temperature molten salt in the low-temperature molten salt tank (24) into the steam-salt heat exchanger (30); the molten salt outlet of the steam-salt heat exchanger (30) is connected to a high-temperature molten salt tank (21), and the bottom outlet of the high-temperature molten salt tank (21) is connected to a heat-releasing molten salt pump (22) that is respectively connected to the molten salt inlets of an air-salt heater (19) and an air-salt reheater (20) and is used to pump the high-temperature molten salt in the high-temperature molten salt tank (21) into the air-salt heater (19) and the air-salt reheater (20). The molten salt outlets of the air-salt heater (19) and the air-salt reheater (20) are both connected to the top inlet of the low-temperature molten salt tank (24), so as to realize that the high-temperature molten salt in the high-temperature molten salt tank (21) heats the air through the air-salt heater (19) and the air-salt reheater (20) during the power generation process of the liquid air expansion power generation subsystem and then enters the low-temperature molten salt tank (24).

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