A compressed air energy storage system coupled with a coal-fired power unit and its operation method

Abstract

This invention discloses a compressed air energy storage system and its operation method coupled to a coal-fired power unit in the field of energy storage technology. The system includes: feedwater from the coal-fired power unit is heated in a boiler to generate steam; part of the steam is de-cooled and depressurized before being supplied as heat, while the other part enters a turbine to perform work; a compression system converts electrical energy from the power grid or the kinetic energy of the coal-fired power unit turbine into gas pressure energy; a gas storage system stores high-pressure gas; an expansion system converts the gas pressure energy output from the gas storage system into expansion kinetic energy to drive a generator; and a heat exchange system transfers the compression heat generated by the compression system to the heat storage unit of the heat exchange system and uses the high-temperature heat source of the heat storage unit to heat the high-pressure, low-temperature gas from the gas storage system into high-pressure, high-temperature gas. This invention can utilize existing equipment and systems of coal-fired power units, ultimately improving the overall conversion efficiency of the compressed air energy storage system.

Description

Technical Field

[0001] This invention relates to a compressed air energy storage system and its operation method coupled to a coal-fired power unit, belonging to the field of energy storage technology. Background Technology

[0002] Compressed air energy storage, as a long-term energy storage method, features rapid start-up and shutdown, long cycle life, and strong load adaptability. It has wide applications in peak shaving and valley filling, renewable energy consumption, grid auxiliary services, and user-side services.

[0003] For coal-fired heating units that are about to be shut down, there is a problem of heat loss after the units are shut down. Current solutions to this problem are mainly: 1) replacing the heat supply with existing nearby heat sources; 2) if there are no alternative heat sources nearby, constructing new electric boilers or coal-fired units. Both of these solutions can resolve the heat loss issue after the units are shut down, but they also result in equipment waste.

[0004] To address the regional heating challenges posed by soon-to-be-shut-down coal-fired power units, existing equipment should be utilized as much as possible to maximize heating safety margins. Simultaneously, considering the significant challenges posed by the increasing proportion of renewable energy to power grids primarily powered by coal-fired power units, existing technologies propose coupling compressed air energy storage systems with coal-fired power units.

[0005] Existing technologies, by absorbing heat from the thermal system of coal-fired units to heat the intake air of the expander, increase the deep peak-shaving capacity of coal-fired units and the conversion efficiency of compressed air energy storage systems, thus achieving the transfer of energy from coal-fired units to compressed air energy storage systems. However, from the perspective of the entire coupled system, the overall system efficiency is reduced, and the problem of continuous heating cannot be solved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a compressed air energy storage system coupled to a coal-fired power unit and its operation method.

[0007] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution.

[0008] In a first aspect, the present invention proposes a compressed air energy storage system coupled to a coal-fired power unit, comprising:

[0009] The thermal system of a coal-fired unit is used to heat feedwater in the boiler to generate steam. Part of the steam is de-heated and depressurized before being supplied to the outside for heat, and the other part of the steam enters the steam turbine to do work.

[0010] The compression system uses electrical energy from the power grid or steam turbines from coal-fired power plants to drive the compressor and convert it into air pressure energy.

[0011] Gas storage system, used to store high-pressure gas generated by the compression system;

[0012] An expansion system is used to convert the air pressure energy output from the gas storage system into expansion kinetic energy to drive a generator to generate electricity.

[0013] The heat exchange system is used to transfer the heat of compression from the compression system to the heat storage unit of the heat exchange system. It is also used to heat the high-pressure, low-temperature air from the gas storage system into high-pressure, high-temperature air using the high-temperature heat source of the heat storage unit.

[0014] Furthermore, the thermal system of the coal-fired unit includes: a boiler, a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a first check valve, a second check valve, a first pressure reducing device, a second pressure reducing device, a first desuperheating device, a second desuperheating device, and a steam-molten salt heat exchanger;

[0015] The superheated steam output end of the boiler is connected to the first valve and the second valve via pipelines.

[0016] The first valve is connected to the first pressure-reducing device via a pipeline. The first pressure-reducing device is connected to the fourth valve and the first desuperheating device via pipelines. The fourth valve is connected to the steam-molten salt heat exchanger via a pipeline. The first desuperheating device and the steam-molten salt heat exchanger are connected to the first check valve via pipelines. The first check valve is connected to the boiler's reheat system via a pipeline.

[0017] The second valve is connected to the high-pressure cylinder of the steam turbine through a pipeline to perform work. After performing work, the steam enters the boiler reheat system through the second check valve.

[0018] The reheat steam from the boiler's reheat system outlet is connected to the third valve and the fifth valve via pipelines.

[0019] The third valve is connected to the intermediate-pressure cylinder of the steam turbine via a pipeline to perform work. The low-pressure steam produced after the intermediate-pressure cylinder performs work is then supplied to the low-pressure heat source user.

[0020] The fifth valve is connected to the second pressure reducing device and the second desuperheating device in sequence through pipelines to supply steam to the medium-pressure heat source user.

[0021] Furthermore, the compression system includes: a steam turbine, a first clutch, a second clutch, a first electric motor, a second electric motor, a first compressor, a second compressor, and a third compressor;

[0022] The high-pressure cylinder of the steam turbine is connected to the second valve through a pipeline, and the intermediate-pressure cylinder of the steam turbine is connected to the third valve through a pipeline;

[0023] The steam turbine, the first clutch, the first compressor, the second compressor, the second clutch, and the first electric motor are connected in sequence, and the third compressor and the second electric motor are connected.

[0024] The first compressor, the second compressor, and the third compressor are connected to the heat exchange system via pipelines.

[0025] Furthermore, the gas storage system is a gas storage tank, and the gas storage tank is connected to the heat exchange system via pipelines.

[0026] Furthermore, the expansion system includes: a first expander, a second expander, and a generator connected in sequence;

[0027] The first expander and the second expander are connected to the heat exchange system via pipelines.

[0028] Furthermore, the heat exchange system includes: a first gas-molten salt heat exchanger, a second gas-molten salt heat exchanger, a third gas-molten salt heat exchanger, a fourth gas-molten salt heat exchanger, a fifth gas-molten salt heat exchanger, a first gas-water heat exchanger, a second gas-water heat exchanger, a third gas-water heat exchanger, a fourth gas-water heat exchanger, a fifth gas-water heat exchanger, a low-temperature molten salt tank, a high-temperature molten salt tank, a low-temperature water tank, and a high-temperature water tank;

[0029] Air enters the inlet of the first-stage compressor. The compressed gas exiting the first-stage compressor is connected via pipeline to the first gas-molten salt heat exchanger and the first gas-water heat exchanger of the first gas-molten salt heat exchange system. The compressed gas exiting the first gas-water heat exchanger is connected via pipeline to the inlet of the second compressor. The compressed gas exiting the second compressor is connected via pipeline to the second gas-molten salt heat exchanger and the second gas-water heat exchanger of the second gas-molten salt heat exchange system. The compressed gas exiting the second gas-water heat exchanger is connected via pipeline to the inlet of the third compressor. The third compressor is connected via pipeline to the third gas-molten salt heat exchanger and the third gas-water heat exchanger of the third gas-molten salt heat exchange system. The compressed gas exiting the third gas-water heat exchanger is connected via pipeline to a gas storage tank.

[0030] The gas storage tank is connected to the first expander through the fourth gas-water heat exchanger and the fourth gas-molten salt heat exchanger of the fourth gas-molten salt heat exchange system;

[0031] The first expander and the second expander are connected by the fifth gas-water heat exchanger and the fifth gas-molten salt heat exchanger of the fifth gas-molten salt heat exchange system;

[0032] The low-temperature molten salt tank is connected to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system, and the third gas-molten salt heat exchange system via molten salt pumps and pipelines, and is then connected to the high-temperature molten salt tank via pipelines.

[0033] The high-temperature molten salt tank is connected to the fourth gas-molten salt heat exchange system and the fifth gas-molten salt heat exchange system via pipelines, and then connected to the high-temperature molten salt tank via pipelines.

[0034] The low-temperature water tank is connected to the first gas-water heat exchange system, the second gas-water heat exchange system, and the third gas-water heat exchange system via a second water pump and pipelines, and is then connected to the high-temperature water tank via pipelines.

[0035] The high-temperature water tank is connected to the fourth gas-water heat exchange system and the fifth gas-water heat exchange system via pipelines, and then connected to the low-temperature water tank via pipelines.

[0036] The high-temperature water tank is also connected to the boiler via a first water pump and pipes.

[0037] In a second aspect, the present invention also improves an operation method for a compressed air energy storage system based on the coupled coal-fired power unit described in the first aspect, comprising:

[0038] Operating Condition 1: Compressed air energy storage system operating alone. The operating process for Operating Condition 1 is as follows:

[0039] The compression process includes: the first clutch disengaging, the turbine not performing work, drawing power from the grid, the first and second electric motors operating, and the second clutch engaging.

[0040] The first electric motor drives the first compressor and the second compressor, and the second electric motor drives the third compressor;

[0041] The gas enters the first compressor and is compressed. The compressed gas, which has been pressurized and heated, enters the first gas-molten salt heat exchanger and the first gas-water heat exchanger of the first gas-molten salt heat exchange system for heat exchange. After being de-cooled, the compressed gas enters the second compressor for compression. The compressed gas, which has been pressurized and heated in the second compressor, enters the second gas-molten salt heat exchanger and the second gas-water heat exchanger of the second gas-molten salt heat exchange system for heat exchange. After being de-cooled, the compressed gas enters the third compressor for compression. The compressed gas, which has been pressurized and heated in the third compressor, enters the third gas-molten salt heat exchanger and the third gas-water heat exchanger of the third gas-molten salt heat exchange system for heat exchange. After being de-cooled, the compressed gas enters the gas storage tank for storage.

[0042] Throughout the heat exchange process, the molten salt in the low-temperature molten salt tank is transported to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system and the third gas-molten salt heat exchange system by the molten salt pump. After being heated, it is returned to the high-temperature molten salt tank, and part of the compressive heat is stored in the molten salt tank.

[0043] High-pressure cryogenic water in the cryogenic water tank is transported to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system and the third gas-molten salt heat exchange system by the third water pump. After being heated, it is returned to the high-temperature water tank. Part of the heat of compression is stored in the high-temperature water tank.

[0044] The expansion process includes: compressed air in the gas storage tank sequentially enters the fourth gas-water heat exchanger and the fourth gas-molten salt heat exchanger of the fourth gas-molten salt heat exchange system to be heated, and then enters the first expander to do work. After being de-heated and depressurized, the compressed air then sequentially enters the fifth gas-water heat exchanger and the fifth gas-molten salt heat exchanger of the fifth heat exchange system to be heated, and then enters the second expander to do work. After being de-heated and depressurized, it is discharged into the atmosphere. The work done by the first and second expanders drives the generator to generate electricity, which is then fed into the power grid.

[0045] Furthermore, it also includes: Operating Condition 2, during the non-heating season, the coal-fired unit is used as a steam boiler for industrial steam supply. The operation process of Operating Condition 2 is as follows:

[0046] The superheated steam output from the boiler flows through the first valve, and after passing through the first pressure reducing device and the first desuperheating device, it is desuperheated and depressurized. When the steam parameters are the same as the high-pressure cylinder exhaust parameters during normal operation of the coal-fired unit, the steam enters the boiler reheat system after passing through the first check valve.

[0047] After being heated, the reheated steam then enters the fifth valve, the second pressure reducing device, and the second desuperheating device. After desuperheating and pressure reduction, the steam parameters meet the needs of industrial users and are supplied to them.

[0048] During operation, the second, third, and fourth valves and the second check valve in the coal-fired power unit system are all in the closed state.

[0049] Furthermore, it also includes: Operating Condition 3, during the non-heating season, the operating condition of the coal-fired unit's industrial steam supply coupled with compressed air energy storage system. The operating process of Operating Condition 3 is as follows:

[0050] The industrial steam supply process on the coal-fired power unit side includes: superheated steam generated by the boiler enters the main steam pipeline; the main steam flows through the second valve into the high-pressure cylinder of the turbine to do work; after desuperheating and depressurization, it enters the boiler reheat system through the second check valve to be heated; part of the reheated steam enters the intermediate-pressure cylinder of the turbine through the third valve to do work; the exhaust steam from the intermediate-pressure cylinder is supplied to low-pressure heat source users; part of the reheated steam flows through the fifth valve and enters the second pressure reducing device and the second desuperheating device in sequence; after depressurization and desuperheating, it is supplied to the industrial steam users of the intermediate-pressure heat source.

[0051] The compression process of the compressed air energy storage system includes: the second clutch disengaging, the first electric motor not performing work; the steam turbine driving the first clutch to operate, driving the first compressor and the second compressor to perform work; wherein, air enters the first compressor for compression, increasing pressure and temperature, and sequentially enters the first gas-molten salt heat exchanger and the first gas-water heat exchanger of the first gas-molten salt heat exchange system for heat exchange, and after cooling, it enters the second compressor for compression; in the second compressor, the air is further pressurized and heated, and sequentially enters the second gas-molten salt heat exchanger and the second gas-water heat exchanger of the second gas-molten salt heat exchange system for heat exchange, and after cooling, it enters the third compressor;

[0052] The second electric motor does work, driving the third compressor to do work. After the compressed air is pressurized and heated, it enters the third gas-molten salt heat exchanger and the third gas-water heat exchanger of the third gas-molten salt heat exchange system in sequence for heat exchange. After cooling, the compressed air enters the gas storage tank for storage.

[0053] During the heat exchange processes of the first, second, and third gas-molten salt heat exchange systems, molten salt in the cryogenic molten salt tank is transported to these systems via a molten salt pump. The cryogenic molten salt is heated to high-temperature molten salt by the heat of compression and then returned to the high-temperature molten salt tank, where some of the heat of compression is stored. Similarly, cryogenic water in the cryogenic water tank is transported to these systems via a second water pump, heated, and then returned to the high-temperature water tank, where some of the heat of compression is stored.

[0054] The expansion process includes: compressed air in the gas storage tank sequentially enters the fourth gas-water heat exchanger and the fourth gas-molten salt heat exchanger of the fourth gas-molten salt heat exchange system to be heated, and then enters the first expander to do work. After being de-cooled and depressurized, the compressed air then sequentially enters the fifth gas-water heat exchanger and the fifth gas-molten salt heat exchanger of the fifth heat exchange system to be heated, and then enters the second expander to do work. After being de-cooled and depressurized, it is discharged into the atmosphere. During the work done by the first and second expanders, the generator drives the generator to generate electrical energy, which is then fed into the power grid.

[0055] Furthermore, in operating condition three, the first valve in the coal-fired unit system is opened, allowing some of the main steam to be depressurized by the first pressure reducing device and then flow through the fourth valve. The steam then exchanges heat in the steam-molten salt heat exchanger, heating the molten salt to a higher temperature.

[0056] After the steam is de-heated and depressurized, it enters the valve and then enters the boiler reheat system to be heated. If the molten salt temperature has reached the preset high temperature, the first valve is closed.

[0057] Furthermore, it also includes: Operating Condition 4, Heating Season, Industrial Operation of Coal-fired Units, Heating and Steam Supply Coupled Compressed Air Energy Storage System. The operating process of Operating Condition 4 is as follows:

[0058] The industrial steam supply and heating steam supply process on the coal-fired power unit side includes: the industrial steam supply process on the coal-fired power unit side includes: superheated steam generated by the boiler enters the main steam pipeline, the main steam flows through the second valve into the high-pressure cylinder of the steam turbine to do work, after de-temperature and pressure reduction, it enters the boiler reheat system through the second check valve to be heated, and part of the reheated steam enters the intermediate-pressure cylinder of the steam turbine through the third valve to do work, the steam exhaust from the intermediate-pressure cylinder of the steam turbine is divided into two paths, one path is for low-pressure industrial users to supply steam, and the other path is for heating steam, which enters the heating network heater to heat the heating network circulating water;

[0059] Part of the reheated steam flows through the fifth valve and enters the second pressure reducing device and the second desuperheating device in sequence. After pressure reduction and desuperheating, it is divided into two paths: one path supplies steam to medium-pressure industrial users, and the other path supplies steam for heating, which enters the heater of the heating network.

[0060] The drain water from the heating network heater is returned to the low-temperature water tank of the heat exchange system. After the heat exchange system heats up, it enters the high-temperature water tank of the heat exchange system and then enters the boiler via the first water pump set.

[0061] The compression process of the compressed air energy storage system includes: the second clutch disengaging, the first electric motor not performing work; the steam turbine driving the first clutch to operate, driving the first compressor and the second compressor to perform work; wherein, the gas enters the first compressor for compression, increasing pressure and temperature, and sequentially enters the first gas-molten salt heat exchanger and the first gas-water heat exchanger of the first gas-molten salt heat exchange system for heat exchange, and after cooling, it enters the second compressor for compression; in the second compressor, the gas is further pressurized and heated, and sequentially enters the second gas-molten salt heat exchanger and the second gas-water heat exchanger of the second gas-molten salt heat exchange system for heat exchange, and after cooling, it enters the third compressor;

[0062] The second electric motor does work, driving the third compressor to do work, further compressing the control ball. After the air is pressurized and heated, it enters the third gas-molten salt heat exchanger and the third gas-water heat exchanger of the third gas-molten salt heat exchange system in sequence for heat exchange. After cooling, it enters the gas storage tank for storage.

[0063] During the heat exchange processes of the first, second, and third gas-molten salt heat exchange systems, molten salt in the cryogenic molten salt tank is transported to these systems via a molten salt pump. The cryogenic molten salt is heated to high-temperature molten salt by the heat of compression and returned to the high-temperature molten salt tank, where some of the heat of compression is stored. Similarly, high-pressure cryogenic water in the cryogenic water tank is transported to the first, second, and third gas-molten salt heat exchange systems via a second water pump. After being heated, the water is returned to the high-temperature water tank, where some of the heat of compression is stored.

[0064] The expansion process includes: compressed air in the gas storage tank sequentially enters the fourth gas-water heat exchanger and the fourth gas-molten salt heat exchanger of the fourth gas-molten salt heat exchange system to be heated, and then enters the first expander to do work. After being de-heated and depressurized, the compressed air then sequentially enters the fifth gas-water heat exchanger and the fifth gas-molten salt heat exchanger of the fifth heat exchange system to be heated, and then enters the second expander to do work. After being de-heated and depressurized, it is discharged into the atmosphere. The work done by the first and second expanders drives the generator to generate electricity, which is then fed into the power grid.

[0065] The beneficial effects achieved by this invention are as follows:

[0066] This invention enables the utilization of existing equipment and systems of coal-fired power units; solves the problems of industrial steam supply and heating after the shutdown of coal-fired power units in some areas; while ensuring industrial steam supply and heating, it uses the work done by the steam turbine to drive the compressor to do work, extracts steam to heat molten salt, thereby increasing the intake temperature of the expander, and ultimately improving the overall conversion efficiency of the compressed air energy storage system. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of the system principle of the present invention. Detailed Implementation

[0068] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0070] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0071] Example 1: This example describes a compressed air energy storage system coupled to a coal-fired power unit, comprising:

[0072] The thermal system of a coal-fired power unit is used to heat feedwater in the boiler to generate steam. Part of the steam is de-cooled and depressurized before being supplied as heat; the other part of the steam enters the turbine to do work, driving the compressor to compress air.

[0073] A compression system is used to drive a compressor via a steam turbine or electric motor to compress ambient air into high-pressure air through a staged compression process, which is then stored in a gas storage system. In other words, it converts electrical energy from the power grid or the internal energy of steam from a coal-fired power plant into air energy for storage.

[0074] The gas storage system is used to store the high-pressure air generated by the compression system in a gas storage tank, and to deliver the high-pressure gas to the expansion system when the expander needs to do work.

[0075] The expansion system is used to transfer the high-pressure air energy from the gas storage system to the expander of the expansion system. The high-temperature and high-pressure air drives the expander to do work, converting the air energy into kinetic energy, which drives the generator to generate electricity.

[0076] In the heat exchange system, during the compressor's operation, the compressor discharges high-pressure, high-temperature air. To improve the efficiency of the next stage compressor, the high-pressure, high-temperature air needs to be cooled to high-pressure, low-temperature air. At this time, in the heat exchange system, the high-pressure, high-temperature air heats the heat exchange medium in the heat exchange system, and the heat of compression is transferred to the heat storage unit of the heat exchange system for storage. When the compressed air energy storage system generates electricity, the high-temperature heat source in the heat exchange system needs to be released to heat the high-pressure, low-temperature air into high-pressure, high-temperature air.

[0077] The thermal system of the coal-fired unit includes: boiler 1-1, first valve 1-2, second valve 1-3, third valve 1-4, fourth valve 1-6, fifth valve 1-11, first check valve 1-9, second check valve 1-10, first pressure reducing device 1-5, second pressure reducing device 1-12, first desuperheating device 1-7, second desuperheating device 1-13, and steam-molten salt heat exchanger 1-8;

[0078] The superheated steam output end of boiler 1-1 is connected to the first valve 1-2 and the second valve 1-3 via pipelines.

[0079] The first valve 1-2 is connected to the first pressure reducing device 1-5 via a pipeline. The first pressure reducing device 1-5 is connected to the fourth valve 1-6 and the first desuperheating device 1-7 via pipelines. The fourth valve 1-6 is connected to the steam-molten salt heat exchanger 1-8 via a pipeline. The first desuperheating device 1-7 and the steam-molten salt heat exchanger 1-8 are connected to the first check valve 1-9 via pipelines. The first check valve 1-9 is connected to the reheat system of boiler 1-1 via a pipeline.

[0080] The second valve 1-3 is connected to the compression system through a pipeline to perform high-pressure work. The de-cooled and depressurized steam after high-pressure work enters the reheat system of boiler 1-1 through the second check valve 1-10.

[0081] The reheat steam output terminal of the reheat system of boiler 1-1 is connected to the third valve 1-4 and the fifth valve 1-11 respectively via pipelines.

[0082] The third valve 1-4 is connected to the compression system via pipeline to perform medium-pressure work. The low-pressure steam generated after the medium-pressure work is then supplied to low-pressure heat source users.

[0083] The fifth valve 1-11 is connected to the second pressure reducing device 1-12 and the second desuperheating device 1-13 in sequence through pipelines to supply steam to the medium-pressure heat source user.

[0084] The compression system includes: a steam turbine 2-1, a first clutch 2-2, a second clutch 2-5, a first electric motor 2-6, a second electric motor 2-8, a first compressor 2-3, a second compressor 2-4, and a third compressor 2-7;

[0085] The high-pressure cylinder of steam turbine 2-1 is connected to the second valve 1-3 via a pipeline, and the intermediate-pressure cylinder of steam turbine 2-1 is connected to the third valve 1-4 via a pipeline;

[0086] Steam turbine 2-1, first clutch 2-2, first compressor 2-3, second compressor 2-4, second clutch 2-5, and first electric motor 2-6 are connected in sequence, and third compressor 2-7 and second electric motor 2-8 are connected.

[0087] The first compressor 2-3, the second compressor 2-4, and the third compressor 2-7 are connected to the heat exchange system via pipelines.

[0088] The gas storage system is a gas storage tank 3, which is connected to a heat exchange system via pipelines.

[0089] The expansion system includes: a first expander 4-1, a second expander 4-2, and a generator 4-3 connected in sequence;

[0090] The first expander 4-1 and the second expander 4-2 are respectively connected to the heat exchange system through pipelines.

[0091] The heat exchange system includes: a first gas-molten salt heat exchanger 5-1, a second gas-molten salt heat exchanger 5-3, a third gas-molten salt heat exchanger 5-5, a fourth gas-molten salt heat exchanger 5-8, a fifth gas-molten salt heat exchanger 5-10, a first gas-water heat exchanger 5-2, a second gas-water heat exchanger 5-4, a third gas-water heat exchanger 5-6, a fourth gas-water heat exchanger 5-7, a fifth gas-water heat exchanger 5-9, a low-temperature molten salt tank 5-11, a high-temperature molten salt tank 5-12, a low-temperature water tank 5-13, and a high-temperature water tank 5-14;

[0092] Gas is introduced into the inlet of the first-stage compressor 2-3. The first-stage compressor 2-3 is connected in sequence via pipes to the first gas-molten salt heat exchanger 5-1 and the first gas-water heat exchanger 5-2 of the first gas-molten salt heat exchange system. The first gas-water heat exchanger 5-2 is connected in sequence via pipes to the inlet of the second compressor 2-4. The second compressor 2-4 is connected in sequence via pipes to the second gas-molten salt heat exchanger 5-3 and the second gas-water heat exchanger 5-4 of the second gas-molten salt heat exchange system. The second gas-water heat exchanger 5-4 is connected in sequence via pipes to the inlet of the third compressor 2-7. The third compressor 2-7 is connected in sequence via pipes to the third gas-molten salt heat exchanger 5-5 and the third gas-water heat exchanger 5-6 of the third gas-molten salt heat exchange system. The third gas-water heat exchanger 5-6 is connected in sequence via pipes to the gas storage tank 3.

[0093] The gas storage tank 3 is connected to the first expander 4-1 through the fourth gas-water heat exchanger 5-7 and the fourth gas-molten salt heat exchanger 5-8 of the fourth gas-molten salt heat exchange system;

[0094] The first expander 4-1 and the second expander 4-2 are connected by the fifth gas-water heat exchanger 5-9 and the fifth gas-molten salt heat exchanger 5-10 of the fifth gas-molten salt heat exchange system.

[0095] The cryogenic molten salt tank 5-11 is connected to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system, the third gas-molten salt heat exchange system, the fourth gas-molten salt heat exchange system, and the fifth gas-molten salt heat exchange system via the molten salt pump 5-15 and pipelines, respectively.

[0096] The high-temperature molten salt tanks 5-12 are connected to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system, the third gas-molten salt heat exchange system, the fourth gas-molten salt heat exchange system, and the fifth gas-molten salt heat exchange system respectively through pipelines;

[0097] The low-temperature water tank 5-13 is connected to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system, the third gas-molten salt heat exchange system, the fourth gas-molten salt heat exchange system, and the fifth gas-molten salt heat exchange system via the second water pump 5-16 and pipelines, respectively.

[0098] High-temperature water tanks 5-14 are connected to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system, the third gas-molten salt heat exchange system, the fourth gas-molten salt heat exchange system, and the fifth gas-molten salt heat exchange system via pipelines.

[0099] The high-temperature water tank 5-14 is also connected to the boiler 1-1 via the first water pump 1-14 and pipelines.

[0100] Example 2, based on the same inventive concept as Example 1, describes an operation method for a compressed air energy storage system coupled to a coal-fired power unit, including:

[0101] Operating Condition 1: Compressed air energy storage system operating alone. The operating process for Operating Condition 1 is as follows:

[0102] The compression process includes: the first clutch 2-2 disengaging, the turbine 2-1 not performing work, drawing power from the grid, the first electric motor 2-6 and the second electric motor 2-8 operating, and the second clutch 2-5 engaging.

[0103] The first electric motor 2-6 drives the first compressor 2-3 and the second compressor 2-4, and the electric motor 2-8 drives the third compressor 2-7;

[0104] Air enters the first compressor 2-3 and is compressed. The compressed gas, which has been pressurized and heated, enters the first gas-molten salt heat exchanger 5-1 and the first gas-water heat exchanger 5-2 of the first gas-molten salt heat exchange system for heat exchange. After cooling, the compressed gas enters the second compressor 2-4 for compression. The compressed gas, which has been pressurized and heated in the second compressor 2-4, enters the second gas-molten salt heat exchanger 5-3 and the second gas-water heat exchanger 5-4 of the second gas-molten salt heat exchange system for heat exchange. After cooling, the compressed gas enters the third compressor 2-7 for compression. The compressed gas, which has been pressurized and heated in the third compressor 2-7, enters the third gas-molten salt heat exchanger 5-5 and the third gas-water heat exchanger 5-6 of the third gas-molten salt heat exchange system for heat exchange. After cooling, the compressed gas enters the gas storage tank 3 for storage.

[0105] Throughout the heat exchange process, the molten salt in the low-temperature molten salt tank 5-11 is transported to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system and the third gas-molten salt heat exchange system by the molten salt pump. After being heated, it is returned to the high-temperature molten salt tank 5-12. Part of the compressive heat is stored in the molten salt tank.

[0106] The high-pressure low-temperature water in the low-temperature water tank 5-13 is transported to the first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system and the third gas-molten salt heat exchange system by the second water pump 5-16. After being heated, it is returned to the high-temperature water tank 5-14, and part of the heat of compression is stored in the high-temperature water tank 5-14.

[0107] The expansion process includes: compressed air in the gas storage tank 3 sequentially enters the fourth gas-water heat exchanger 5-7 and the fourth gas-molten salt heat exchanger 5-8 of the fourth gas-molten salt heat exchange system to be heated, and then enters the first expander 4-1 to do work. After being de-heated and depressurized, the compressed air then sequentially enters the fifth gas-water heat exchanger 5-9 and the fifth gas-molten salt heat exchanger 5-10 of the fifth heat exchange system to be heated, and then enters the second expander 4-2 to do work. After being de-heated and depressurized, it is discharged into the atmosphere. During the work of the first expander 4-1 and the second expander 4-2, the generator 4-3 is driven to generate electrical energy, which is then fed into the power grid.

[0108] This also includes: Operating Condition 2, during the non-heating season, when the coal-fired unit is used as a steam boiler for industrial steam supply. The operation process of Operating Condition 2 is as follows:

[0109] The superheated steam output from boiler 1-1 flows through the first valve 1-2, and after passing through the first pressure reducing device 1-5 and the first desuperheating device 1-7, the superheated steam is desuperheated and depressurized. When the steam parameters are the same as the high-pressure cylinder exhaust parameters during normal operation of the coal-fired unit, the steam enters the boiler reheat system after passing through the first check valve 1-9.

[0110] The heated steam then enters the fifth valve 1-11, the second pressure reducing device 1-12, and the second desuperheating device 1-13. After desuperheating and pressure reduction, the steam parameters meet the needs of industrial users and are supplied to them.

[0111] During operation, the second valve 1-3, the third valve 1-4, the fourth valve 1-6, and the second check valve 1-10 in the coal-fired unit system are all in the closed state.

[0112] This also includes: Operating Condition 3, during the non-heating season, the operating condition of the coal-fired unit's industrial steam supply coupled with compressed air energy storage system. The operating process of Operating Condition 3 is as follows:

[0113] The industrial steam supply process on the coal-fired unit side includes: superheated steam generated by boiler 1-1 enters the main steam pipeline, the main steam flows through the second valve 1-3 into the high-pressure cylinder of turbine 2-1 to do work, after de-temperature and pressure reduction, it enters the reheat system of boiler 1-1 through the second check valve 1-10 to be heated, part of the reheat steam enters the intermediate-pressure cylinder of turbine 2-1 through the third valve 1-4 to do work, the intermediate-pressure cylinder exhaust steam to supply steam to low-pressure heat source users; part of the reheat steam flows through the fifth valve 1-11, and enters the second pressure reducing device 1-12 and the second de-temperature device 1-13 in sequence, after pressure reduction and de-temperature reduction, steam is supplied to the industrial steam users of the intermediate-pressure heat source.

[0114] The compression process of the compressed air energy storage system includes: the second clutch 2-5 is disengaged, and the first electric motor 2-6 does no work; the steam turbine 2-1 drives the first clutch 2-2 to operate, driving the first compressor 2-3 and the second compressor 2-4 to do work; wherein, the gas enters the first compressor 2-3 for compression, and is pressurized and heated, and then enters the first gas-molten salt heat exchanger 5-1 and the first gas-water heat exchanger 5-2 of the first gas-molten salt heat exchanger system for heat exchange, and after cooling, it enters the second compressor 2-4 for compression; in the second compressor 2-4, the gas is pressurized and heated, and then enters the second gas-molten salt heat exchanger 5-3 and the second gas-water heat exchanger 5-4 of the second gas-molten salt heat exchanger system for heat exchange, and after cooling, it enters the third compressor 2-7;

[0115] The second electric motor 2-8 performs work to drive the third compressor 2-7 to compress, increase pressure and temperature, and then enter the third gas-molten salt heat exchanger 5-5 and the third gas-water heat exchanger 5-6 of the third gas-molten salt heat exchange system for heat exchange. After cooling, it enters the gas storage tank 3 for storage.

[0116] During the heat exchange processes of the first, second, and third gas-molten salt heat exchange systems, molten salt in the low-temperature molten salt tank 5-11 is transported to these systems via molten salt pump 5-15, and after being heated, it returns to the high-temperature molten salt tank 5-12, where some of the compressive heat is stored. Similarly, high-pressure low-temperature water in the low-temperature water tank 5-13 is transported to these systems via second pump 5-16, and after being heated, it returns to the high-temperature water tank 5-14, where some of the compressive heat is stored.

[0117] The expansion process includes: compressed air in the gas storage tank 3 sequentially enters the fourth gas-water heat exchanger 5-7 and the fourth gas-molten salt heat exchanger 5-8 of the fourth gas-molten salt heat exchange system to be heated, and then enters the first expander 4-1 to do work. After being de-heated and depressurized, the compressed air then sequentially enters the fifth gas-water heat exchanger 5-9 and the fifth gas-molten salt heat exchanger 5-10 of the fifth heat exchange system to be heated, and then enters the second expander 4-2 to do work. After being de-heated and depressurized, the compressed air is discharged into the atmosphere. The work done by the first expander 4-1 and the second expander 4-2 drives the generator 4-3 to generate electricity, which is then fed into the power grid.

[0118] In operating condition 3, the first valve 1-2 of the coal-fired unit system is opened, so that part of the main steam is depressurized by the first pressure reducing device 1-5 and flows through the fourth valve 1-6. The steam then exchanges heat in the steam-molten salt heat exchanger 1-8 to heat the molten salt to a higher temperature.

[0119] After de-heating and de-pressure reduction, the steam enters valve 1-9 and then enters the reheat system of boiler 1-1 to be heated. If the molten salt temperature has reached the preset high temperature, the first valve 1-2 is closed.

[0120] This also includes: Operating Condition 4, Heating Season, Industrial Operation of Coal-fired Units and Heating / Steam Supply Coupled Compressed Air Energy Storage System. The operating process of Operating Condition 4 is as follows:

[0121] The industrial steam supply and heating steam supply process on the coal-fired unit side includes: the industrial steam supply process on the coal-fired unit side includes: superheated steam generated by boiler 1-1 enters the main steam pipeline, the main steam flows through the second valve 1-3 into the high-pressure cylinder of turbine 2-1 to do work, after de-temperature and pressure reduction, it enters the reheat system of boiler 1-1 through the second check valve 1-10 to be heated, and part of the reheated steam enters the intermediate-pressure cylinder of turbine 2-1 through the third valve 1-4 to do work, the intermediate-pressure cylinder exhaust is divided into two paths, one is low-pressure industrial steam supply, and the other is heating steam supply, which enters the heating network heater;

[0122] Part of the reheated steam flows through the fifth valve 1-11 and enters the second pressure reducing device 1-12 and the second desuperheating device 1-13 in sequence. After pressure reduction and desuperheating, it is divided into two paths: one is medium-pressure industrial steam supply, and the other is heating steam supply, which enters the heating network heater.

[0123] The drain water from the heating network heater is returned to the low-temperature water tank 5-13 of the heat exchange system. After the heat exchange system is heated, it enters the high-temperature water tank 5-14 of the heat exchange system, and then enters the boiler 1-1 via the first water pump group 1-14.

[0124] The compression process of the compressed air energy storage system includes: the second clutch 2-5 is disengaged, and the first electric motor 2-6 does no work; the steam turbine 2-1 drives the first clutch 2-2 to operate, driving the first compressor 2-3 and the second compressor 2-4 to do work; wherein, the gas enters the first compressor 2-3 for compression, and is pressurized and heated, and then enters the first gas-molten salt heat exchanger 5-1 and the first gas-water heat exchanger 5-2 of the first gas-molten salt heat exchanger system for heat exchange, and after cooling, it enters the second compressor 2-4 for compression; in the second compressor 2-4, the gas is pressurized and heated, and then enters the second gas-molten salt heat exchanger 5-3 and the second gas-water heat exchanger 5-4 of the second gas-molten salt heat exchanger system for heat exchange, and after cooling, it enters the third compressor 2-7;

[0125] The second electric motor 2-8 performs work to drive the third compressor 2-7 to compress, increase pressure and temperature, and then enter the third gas-molten salt heat exchanger 5-5 and the third gas-water heat exchanger 5-6 of the third gas-molten salt heat exchange system for heat exchange. After cooling, it enters the gas storage tank 3 for storage.

[0126] During the heat exchange processes of the first, second, and third gas-molten salt heat exchange systems, molten salt in the low-temperature molten salt tank 5-11 is transported to these systems via molten salt pump 5-15, and after being heated, it returns to the high-temperature molten salt tank 5-12, where some of the compressive heat is stored. Similarly, high-pressure low-temperature water in the low-temperature water tank 5-13 is transported to these systems via second pump 5-16, and after being heated, it returns to the high-temperature water tank 5-14, where some of the compressive heat is stored.

[0127] The expansion process includes: compressed air in the gas storage tank 3 sequentially enters the fourth gas-water heat exchanger 5-7 and the fourth gas-molten salt heat exchanger 5-8 of the fourth gas-molten salt heat exchange system to be heated, and then enters the first expander 4-1 to do work. After being de-heated and depressurized, the compressed air then sequentially enters the fifth gas-water heat exchanger 5-9 and the fifth gas-molten salt heat exchanger 5-10 of the fifth heat exchange system to be heated, and then enters the second expander 4-2 to do work. After being de-heated and depressurized, the compressed air is discharged into the atmosphere. The work done by the first expander 4-1 and the second expander 4-2 drives the generator 4-3 to generate electricity, which is then fed into the power grid.

[0128] Example 3, based on the same inventive concept as Example 1, introduces a compressed air energy storage system coupled to a coal-fired power unit, comprising:

[0129] 1) The thermal system of the coal-fired unit includes: boiler 1-1, first valve 1-2, second valve 1-3, third valve 1-4, fourth valve 1-6, fifth valve 1-11, first check valve 1-9, second check valve 1-10, first pressure reducing device 1-5, second pressure reducing device 1-12, first desuperheating device 1-7, second desuperheating device 1-13, steam-molten salt heat exchanger 1-8 and its associated steam and water pipelines;

[0130] 2) Compression system, including: steam turbine 2-1, first clutch 2-2, second clutch 2-5, first electric motor 2-6, second electric motor 2-8, first compressor 2-3, second compressor 2-4 and third compressor 2-7;

[0131] 3) The gas storage system is gas storage cell 3;

[0132] 4) The expansion system consists of: a first expander 4-1, a second expander 4-2, and a generator 4-3;

[0133] 5) Heat exchange system, including: first gas-molten salt heat exchanger 5-1, second gas-molten salt heat exchanger 5-3, third gas-molten salt heat exchanger 5-5, fourth gas-molten salt heat exchanger 5-8, fifth gas-molten salt heat exchanger 5-10, first gas-water heat exchanger 5-2, second gas-water heat exchanger 5-4, third gas-water heat exchanger 5-6, fourth gas-water heat exchanger 5-7, fifth gas-water heat exchanger 5-9, low temperature molten salt tank 5-11, high temperature molten salt tank 5-12, low temperature water tank 5-13 and high temperature water tank 5-14.

[0134] Operating conditions include:

[0135] (a) Operating condition of compressed air energy storage system alone: ​​The coal-fired unit is in a shutdown state, and the compressed air energy storage system operates as an independent power station.

[0136] Compression process: The first clutch 2-2 disengages, and the turbine does no work. Power is drawn from the grid, and the first motor 2-6 and the second motor 2-8 operate. The second clutch 2-5 closes and operates. The first motor 2-6 drives the first compressor 2-3 and the second compressor 2-4; the second motor 2-8 drives the third compressor 2-7. Air enters the first compressor 2-3 and is compressed, increasing in pressure and temperature. The compressed air then sequentially enters the first gas-molten salt heat exchanger 5-1 and the first gas-water heat exchanger 5-2 of the first gas-molten salt heat exchange system for heat exchange. After cooling, the compressed air enters the second compressor 2-4 for compression. In the second compressor, the air is again compressed and heated, and then sequentially enters the second gas-molten salt heat exchanger 5-3 and the second gas-water heat exchanger 5-4 of the second gas-molten salt heat exchange system for heat exchange. After cooling, the compressed air enters the third compressor 2-7 for compression. In the third compressor, the air is further compressed and heated, and then sequentially enters the third gas-molten salt heat exchanger 5-5 and the third gas-water heat exchanger 5-6 of the third gas-molten salt heat exchange system for heat exchange. After cooling, the compressed air enters the gas storage tank 3 for storage. Throughout the heat exchange process, the molten salt in the low-temperature molten salt tank 5-11 is transported to the heat exchange system via the molten salt pump 5-15, heated, and then returned to the high-temperature molten salt tank 5-12. Part of the compressive heat is stored in the high-temperature molten salt tank 5-12. The high-pressure low-temperature water in the low-temperature water tank 5-13 is transported to the heat exchange system via the second water pump 5-16, heated, and then returned to the high-temperature water tank 5-14. Part of the compressive heat is stored in the high-temperature water tank 5-14.

[0137] Expansion process: Compressed air in storage tank 3 sequentially enters the fourth gas-water heat exchanger 5-7 and the fourth gas-molten salt heat exchanger 5-8 of the heat exchange system, where it is heated and then enters the first expander 4-1 to perform work. After being de-cooled and depressurized, the compressed air then sequentially enters the fifth gas-water heat exchanger 5-9 and the fifth gas-molten salt heat exchanger 5-10 of the heat exchange system, where it is heated and then enters the second expander 4-2 to perform work. After being de-cooled and depressurized, it is discharged into the atmosphere. During the work performed by the expander, it drives generator 4-3 to generate electricity, which is then fed into the power grid.

[0138] During the non-heating season, coal-fired power units are used as steam boilers for industrial steam supply.

[0139] Under this condition, the compressed air energy storage system is shut down, and the coal-fired unit is used only as a heating boiler for industrial steam supply; steam does not enter the turbine to do work.

[0140] Superheated steam from boiler 1-1 outlet flows through the first valve 1-2, then through the first pressure reducing device 1-5 and the first desuperheating device 1-7. After the superheated steam is desuperheated and depressurized, and its parameters are essentially the same as the high-pressure cylinder exhaust parameters during normal operation of the coal-fired unit, it enters the boiler reheat system after passing through the first check valve 1-9. The heated steam then enters the fifth valve 1-11, the second pressure reducing device 1-12, and the second desuperheating device 1-13. After desuperheating and pressure reduction, the steam parameters meet the needs of industrial users and are supplied to them.

[0141] During operation under these conditions, valves 1-3 (second), 1-4 (third), 1-6 (fourth), and 1-10 (second check valve) in the coal-fired unit system are all closed. Because industrial steam is supplied externally, the original water supply flow rate of the coal-fired unit's water supply system must meet system requirements; some of the desuperheated and depressurized reheated steam can be used to heat the condensate water to meet the boiler's requirements for inlet water parameters.

[0142] (III) Operating conditions of coal-fired unit industrial steam supply coupled with compressed air energy storage system during non-heating season: During the non-heating season, coal-fired unit needs to supply steam to external industries and drive the steam turbine.

[0143] Industrial steam supply process of coal-fired power units and compression process of compressed air energy storage system:

[0144] Industrial steam supply process on the coal-fired unit side: Superheated steam generated by boiler 1-1 enters the main steam pipeline. The main steam flows through the second valve 1-3 into the high-pressure cylinder of turbine 2-1 to do work. After depressurization and cooling, it enters the reheat system of boiler 1-1 through the second check valve 1-10 to be heated. Part of the reheated steam enters the intermediate-pressure cylinder of turbine 2-1 through the third valve 1-4 to do work. The exhaust steam from the intermediate-pressure cylinder can supply steam to low-pressure heat source users. Part of the reheated steam flows through the fifth valve 1-11 and sequentially enters the second pressure reducing device 1-12 and the second desuperheating device 1-13 (spray water desuperheating system). After depressurization and cooling, steam is supplied to the industrial steam users of the intermediate-pressure heat source.

[0145] The compression process of the compressed air energy storage system is as follows: The second clutch 2-5 is disengaged, and the first electric motor 2-6 does no work. The steam turbine 2-1 drives the first clutch 2-2 to operate, driving the first compressor 2-3 and the second compressor 2-4 to perform work. Specifically, air enters the first compressor 2-3 for compression, increasing pressure and temperature, and then sequentially enters the first gas-molten salt heat exchanger 5-1 and the first gas-water heat exchanger 5-2 of the first gas-molten salt heat exchange system for heat exchange. After cooling, it enters the second compressor 2-4 for compression. In the second compressor, the air is further compressed and heated, then sequentially enters the second gas-molten salt heat exchanger 5-3 and the second gas-water heat exchanger 5-4 of the second gas-molten salt heat exchange system for heat exchange. After cooling, it enters the third compressor 2-7. The second electric motor 2-8 performs work, driving the third compressor 2-7 for compression, increasing pressure and temperature, then sequentially enters the third gas-molten salt heat exchanger 5-5 and the third gas-water heat exchanger 5-6 of the third gas-molten salt heat exchange system for heat exchange. After cooling, it enters the air storage tank 3 for storage. Throughout the heat exchange process, the molten salt in the low-temperature molten salt tank 5-11 is transported to the heat exchange system via the molten salt pump 5-15, heated, and then returned to the high-temperature molten salt tank 5-12. Part of the compressive heat is stored in the high-temperature molten salt tank 5-12. The high-pressure low-temperature water in the low-temperature water tank 5-13 is transported to the heat exchange system via the second water pump 5-16, heated, and then returned to the high-temperature water tank 5-14. Part of the compressive heat is stored in the high-temperature water tank 5-14.

[0146] To increase the expander inlet temperature, the first valve 1-2 in the coal-fired unit system can be opened, allowing some of the main steam to be depressurized by the first pressure reducing device 1-5. After passing through the fourth valve 1-6, the steam exchanges heat in the steam-molten salt heat exchanger 1-8, heating the molten salt to a higher temperature, thereby increasing the expander inlet parameters. After depressurization and cooling, the steam enters the first check valve 1-9 and then enters the reheat system of boiler 1-1 for further heating. If the molten salt temperature is already high enough, the first valve 1-2 can be closed.

[0147] Expansion process: This process is consistent with that of a compressed air energy storage system operating independently. However, because the main steam of the coal-fired unit heats the molten salt, the inlet temperature of the expander can be raised to higher parameters, increasing the expander efficiency. Under the premise of constant expander inlet flow rate, the output of the first expander 4-1 and the second expander 4-2 is higher, and the output power of the generator 4-3 increases.

[0148] (iv) Operating conditions of coal-fired unit industrial and heating steam supply coupled compressed air energy storage system during heating season: During the heating season, coal-fired unit needs to supply steam to external industries and heating, and drive the steam turbine to run.

[0149] Industrial steam supply process of coal-fired power units and compression process of compressed air energy storage system:

[0150] Industrial steam supply and heating steam supply process on the coal-fired unit side: Under this operating condition, the steam supply process is basically the same as the operating condition of the coal-fired unit industrial steam supply coupled compressed air energy storage system during the non-heating season (III), the difference being that

[0151] The exhaust steam from the intermediate-pressure cylinder of turbine 2-1 can be split into two paths: one for low-pressure industrial steam supply and the other for heating steam supply, which enters the heating network heater. The steam from the reheat system outlet of boiler 1-1 to the second desuperheating device 1-13 can also be split into two paths: one for intermediate-pressure industrial steam supply and the other for heating steam supply, which enters the heating network heater.

[0152] The drain water from the heating network heater is returned to the low-temperature water tank 5-13 of the heat exchange system. After being heated in the heat exchange system, it enters the high-temperature water tank 5-14, and then enters the boiler 1-1 system via the first water pump 1-14.

[0153] Compression process of compressed air energy storage system: This process is consistent with the operating conditions of the compressed air energy storage system coupled with industrial steam supply of coal-fired units during the non-heating season (III).

[0154] Expansion process: This process is consistent with the operating conditions of the industrial steam supply coupled compressed air energy storage system of coal-fired units during the non-heating season (III).

[0155] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0156] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0157] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0158] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0159] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A compressed air energy storage system coupled to a coal-fired power unit, characterized in that, include: The thermal system of a coal-fired unit is used to heat feedwater in the boiler to generate steam. Part of the steam is de-heated and depressurized before being supplied to the outside for heat, and the other part of the steam enters the steam turbine to do work. The compression system uses electrical energy from the power grid or steam turbines from coal-fired power plants to drive the compressor and convert it into air pressure energy. Gas storage system, used to store high-pressure gas generated by the compression system; An expansion system is used to convert the air pressure energy output from the gas storage system into expansion kinetic energy to drive a generator to generate electricity. The heat exchange system is used to transfer the heat of compression generated by the compression system to the heat storage unit of the heat exchange system, and also to use the high-temperature heat source of the heat storage unit to heat the high-pressure low-temperature gas from the gas storage system into high-pressure high-temperature gas. The thermal system of the coal-fired unit includes: a boiler (1-1), a first valve (1-2), a second valve (1-3), a third valve (1-4), a fourth valve (1-6), a fifth valve (1-11), a first check valve (1-9), a second check valve (1-10), a first pressure reducing device (1-5), a second pressure reducing device (1-12), a first desuperheating device (1-7), a second desuperheating device (1-13), and a steam-molten salt heat exchanger (1-8). The superheated steam output end of the boiler (1-1) is connected to the first valve (1-2) and the second valve (1-3) through pipelines. The first valve (1-2) is connected to the first pressure reducing device (1-5) via a pipeline. The first pressure reducing device (1-5) is connected to the fourth valve (1-6) and the first desuperheating device (1-7) via pipelines. The fourth valve (1-6) is connected to the steam-molten salt heat exchanger (1-8) via a pipeline. The first desuperheating device (1-7) and the steam-molten salt heat exchanger (1-8) are connected to the first check valve (1-9) via pipelines. The first check valve (1-9) is connected to the reheat system of the boiler (1-1) via a pipeline. The second valve (1-3) is connected to the high-pressure cylinder of the steam turbine through a pipeline to perform work. After performing work, the steam enters the reheat system of the boiler (1-1) through the second check valve (1-10). The reheat steam from the reheat system outlet of the boiler (1-1) is connected to the third valve (1-4) and the fifth valve (1-11) via pipelines. The third valve (1-4) is connected to the intermediate-pressure cylinder of the steam turbine via a pipeline to perform work. The low-pressure steam produced after work in the intermediate-pressure cylinder is then supplied to the low-pressure heat source user. The fifth valve (1-11) is connected to the second pressure reducing device (1-12) and the second desuperheating device (1-13) in sequence through pipelines to supply steam to the medium-pressure heat source user; The compression system includes: a steam turbine (2-1), a first clutch (2-2), a second clutch (2-5), a first electric motor (2-6), a second electric motor (2-8), a first compressor (2-3), a second compressor (2-4), and a third compressor (2-7). The high-pressure cylinder of the steam turbine (2-1) is connected to the second valve (1-3) through a pipeline, and the intermediate-pressure cylinder of the steam turbine (2-1) is connected to the third valve (1-4) through a pipeline. The steam turbine (2-1), the first clutch (2-2), the first compressor (2-3), the second compressor (2-4), the second clutch (2-5), and the first electric motor (2-6) are connected in sequence, and the third compressor (2-7) and the second electric motor (2-8) are connected. The first compressor (2-3), the second compressor (2-4), and the third compressor (2-7) are connected to the heat exchange system via pipelines; The gas storage system is a gas storage tank (3), and the gas storage tank (3) is connected to a heat exchange system through pipelines; The expansion system includes a first expander (4-1), a second expander (4-2), and a generator (4-3) connected in sequence. The first expander (4-1) and the second expander (4-2) are respectively connected to the heat exchange system through pipelines; The heat exchange system includes: a first gas-molten salt heat exchanger (5-1), a second gas-molten salt heat exchanger (5-3), a third gas-molten salt heat exchanger (5-5), a fourth gas-molten salt heat exchanger (5-8), a fifth gas-molten salt heat exchanger (5-10), a first gas-water heat exchanger (5-2), a second gas-water heat exchanger (5-4), a third gas-water heat exchanger (5-6), a fourth gas-water heat exchanger (5-7), a fifth gas-water heat exchanger (5-9), a low-temperature molten salt tank (5-11), a high-temperature molten salt tank (5-12), a low-temperature water tank (5-13), and a high-temperature water tank (5-14). Air enters the inlet of the first-stage compressor (2-3). The compressed gas from the outlet of the first-stage compressor (2-3) is connected in sequence to the first gas-molten salt heat exchanger (5-1) and the first gas-water heat exchanger (5-2) via pipelines. The compressed air from the outlet of the first gas-water heat exchanger (5-2) is connected in sequence to the inlet of the second compressor (2-4) via pipelines. The compressed air from the outlet of the second compressor (2-4) is connected in sequence to the second gas-molten salt heat exchanger (5-3) and the second gas-water heat exchanger (5-4) via pipelines. The compressed air from the outlet of the second gas-water heat exchanger (5-4) is connected in sequence to the inlet of the third compressor (2-7) via pipelines. The third compressor (2-7) is connected in sequence to the third gas-molten salt heat exchanger (5-5) and the third gas-water heat exchanger (5-6) via pipelines. The compressed air from the outlet of the third gas-water heat exchanger (5-6) is connected in sequence to the gas storage tank (3) via pipelines. The gas storage tank (3) is connected to the first expander (4-1) via the fourth gas-water heat exchanger (5-7) and the fourth gas-molten salt heat exchanger (5-8); The first expander (4-1) and the second expander (4-2) are connected by the fifth gas-water heat exchanger (5-9) and the fifth gas-molten salt heat exchanger (5-10); The low-temperature molten salt tank (5-11) is connected to the first gas-molten salt heat exchanger (5-1), the second gas-molten salt heat exchanger (5-3), and the third gas-molten salt heat exchanger (5-5) through the molten salt pump (5-15) and pipelines, and is then connected to the high-temperature molten salt tank (5-12) through pipelines. The high-temperature molten salt tank (5-12) is connected to the fourth gas-molten salt heat exchanger (5-8) and the fifth gas-molten salt heat exchanger (5-10) through pipelines, and then connected to the low-temperature molten salt tank (5-11) through pipelines. The low-temperature water tank (5-13) is connected to the first gas-water heat exchanger (5-2), the second gas-water heat exchanger (5-4), and the third gas-water heat exchanger (5-6) through the second water pump (5-16) and pipelines, and is then connected to the high-temperature water tank (5-14) through pipelines. The high-temperature water tank (5-14) is connected to the fourth gas-water heat exchanger (5-7) and the fifth gas-water heat exchanger (5-9) through pipes, and then connected to the low-temperature water tank (5-13) through pipes. The high-temperature water tank (5-14) is also connected to the boiler (1-1) via the first water pump (1-14) and pipes.

2. An operation method for a compressed air energy storage system based on a coupled coal-fired power unit as described in claim 1, characterized in that, include: Operating Condition 1: Compressed air energy storage system operating alone. The operating process for Operating Condition 1 is as follows: The compression process includes: the first clutch (2-2) disengaging, the turbine (2-1) not performing work, drawing power from the grid, the first electric motor (2-6) and the second electric motor (2-8) operating, and the second clutch (2-5) engaging. The first electric motor (2-6) drives the first compressor (2-3) and the second compressor (2-4), and the second electric motor (2-8) drives the third compressor (2-7). The gas enters the first compressor (2-3) and is compressed. The compressed gas, which is pressurized and heated, enters the first gas-molten salt heat exchanger (5-1) and the first gas-water heat exchanger (5-2) for heat exchange. After cooling, the compressed gas enters the second compressor (2-4) for compression. The compressed gas, which is pressurized and heated in the second compressor (2-4), enters the second gas-molten salt heat exchanger (5-3) and the second gas-water heat exchanger (5-4) for heat exchange. After cooling, the compressed gas enters the third compressor (2-7) for compression. The compressed gas, which is pressurized and heated in the third compressor (2-7), enters the third gas-molten salt heat exchanger (5-5) and the third gas-water heat exchanger (5-6) for heat exchange. After cooling, the compressed gas enters the gas storage tank (3) for storage. Throughout the heat exchange process, the molten salt in the low-temperature molten salt tank (5-11) is transported to the first gas-molten salt heat exchanger (5-1), the second gas-molten salt heat exchanger (5-3), and the third gas-molten salt heat exchanger (5-5) by the molten salt pump. After being heated, it returns to the high-temperature molten salt tank (5-12), and part of the compressive heat is stored in the molten salt tank. High-pressure low-temperature water in the low-temperature water tank (5-13) is transported to the first gas-water heat exchanger (5-2), the second gas-water heat exchanger (5-4) and the third gas-water heat exchanger (5-6) by the second water pump (5-16). After being heated, it is returned to the high-temperature water tank (5-14), and part of the heat of compression is stored in the high-temperature water tank (5-14). The expansion process includes: compressed air in the gas storage tank (3) enters the fourth gas-water heat exchanger (5-7) and the fourth gas-molten salt heat exchanger (5-8) in sequence to be heated and then enters the first expander (4-1) to do work. After depressurization and cooling, the compressed air enters the fifth gas-water heat exchanger (5-9) and the fifth gas-molten salt heat exchanger (5-10) in sequence to be heated and then enters the second expander (4-2) to do work. After depressurization and cooling, it is discharged into the atmosphere. The first expander (4-1) and the second expander (4-2) drive the generator (4-3) to generate electrical energy, which is then connected to the power grid.

3. The operating method according to claim 2, characterized in that, Also includes: Operating Condition 2: During the non-heating season, the coal-fired unit is used as a steam boiler for industrial steam supply. The operation process under this condition is as follows: The superheated steam output from the boiler (1-1) flows through the first valve (1-2), and after passing through the first pressure reducing device (1-5) and the first desuperheating device (1-7), the superheated steam is desuperheated and depressurized. When the steam parameters are the same as the exhaust parameters of the high-pressure cylinder of the turbine (2-1) during normal operation of the coal-fired unit, the steam enters the reheat system of the boiler (1-1) after passing through the first check valve (1-9). After being heated, the reheated steam enters the fifth valve (1-11), the second pressure reducing device (1-12), and the second desuperheating device (1-13) in sequence. After desuperheating and pressure reduction, the steam parameters meet the needs of industrial users and are supplied to industrial users. During operation, the second valve (1-3), the third valve (1-4), the fourth valve (1-6), and the second check valve (1-10) in the coal-fired unit system are all in the closed state.

4. The operating method according to claim 2, characterized in that, Also includes: Operating Condition 3: Non-heating season, operating condition of the coal-fired unit's industrial steam supply coupled compressed air energy storage system. The operating process of this operating condition is as follows: The industrial steam supply process on the coal-fired power unit side includes: superheated steam generated by boiler (1-1) enters the main steam pipeline, the main steam flows through the second valve (1-3) into the high-pressure cylinder of turbine (2-1) to do work, after de-temperature and pressure reduction, it enters the reheat system of boiler (1-1) through the second check valve (1-10) to be heated, part of the reheated steam enters the intermediate-pressure cylinder of turbine (2-1) through the third valve (1-4) to do work, the exhaust steam from the intermediate-pressure cylinder is supplied to low-pressure heat source industrial users; part of the reheated steam flows through the fifth valve (1-11) and enters the second pressure reducing device (1-12) and the second de-temperature device (1-13) in sequence, after pressure reduction and de-temperature reduction, steam is supplied to medium-pressure heat source industrial steam users; The compression process of the compressed air energy storage system includes: the second clutch (2-5) is disengaged, and the first electric motor (2-6) does no work; the steam turbine (2-1) drives the first clutch (2-2) to operate, driving the first compressor (2-3) and the second compressor (2-4) to do work; wherein, air enters the first compressor (2-3) for compression, pressurization and temperature increase, and sequentially enters the first gas-molten salt heat exchanger (5-1) and the first gas-water heat exchanger (5-2) for heat exchange, and after cooling, it enters the second compressor (2-4) for compression; in the second compressor (2-4), the air is pressurized and heated, and sequentially enters the second gas-molten salt heat exchanger (5-3) and the second gas-water heat exchanger (5-4) for heat exchange, and after cooling, it enters the third compressor (2-7). The second electric motor (2-8) does work, driving the third compressor (2-7) to do work. After the compressed gas is pressurized and heated, it enters the third gas-molten salt heat exchanger (5-5) and the third gas-water heat exchanger (5-6) for heat exchange. After the compressed air is cooled, it enters the gas storage tank (3) for storage. During the heat exchange process, the molten salt in the low-temperature molten salt tank (5-11) is transported by the molten salt pump (5-15) to the first gas-molten salt heat exchanger (5-1), the second gas-molten salt heat exchanger (5-3), and the third gas-molten salt heat exchanger (5-5). The low-temperature molten salt is heated by the heat of compression into high-temperature molten salt and returned to the high-temperature molten salt tank (5-12). Part of the heat of compression is stored in the high-temperature molten salt tank (5-12). The low-temperature water in the low-temperature water tank (5-13) is transported by the second water pump (5-16) to the first gas-water heat exchanger (5-2), the second gas-water heat exchanger (5-4), and the third gas-water heat exchanger (5-6). After being heated, it is returned to the high-temperature water tank (5-14). Part of the heat of compression is stored in the high-temperature water tank (5-14). The expansion process includes: compressed air in the gas storage tank (3) enters the fourth gas-water heat exchanger (5-7) and the fourth gas-molten salt heat exchanger (5-8) in sequence to be heated and then enters the first expander (4-1) to do work. After being de-heated and depressurized, the compressed air then enters the fifth gas-water heat exchanger (5-9) and the fifth gas-molten salt heat exchanger (5-10) in sequence to be heated and then enters the second expander (4-2) to do work. After being de-heated and depressurized, it is discharged into the atmosphere. The first expander (4-1) and the second expander (4-2) do work to drive the generator (4-3) to generate electrical energy, which is then connected to the power grid.

5. The operating method according to claim 2, characterized in that, In operating condition 3, the first valve (1-2) of the coal-fired unit system is opened, so that part of the main steam is depressurized by the first pressure reducing device (1-5), flows through the fourth valve (1-6), and then the steam exchanges heat in the steam-molten salt heat exchanger (1-8) to heat the molten salt to a higher temperature. After de-heating and de-pressure reduction, the steam enters valve (1-9) and then enters the boiler (1-1) reheat system to be heated. If the molten salt temperature has reached the preset high temperature, the first valve (1-2) is closed.

6. The operating method according to claim 2, characterized in that, Also includes: Operating Condition 4: Heating Season - Operating Condition of Coal-fired Unit Industrial Heating and Steam Supply Coupled Compressed Air Energy Storage System. The operating process of Operating Condition 4 is as follows: The industrial steam supply and heating steam supply process on the coal-fired unit side includes: the industrial steam supply process on the coal-fired unit side includes: superheated steam generated by boiler (1-1) enters the main steam pipeline, the main steam flows through the second valve (1-3) into the high-pressure cylinder of turbine (2-1) to do work, after de-temperature and pressure reduction, it enters the reheat system of boiler (1-1) through the second check valve (1-10) to be heated, and part of the reheated steam enters the intermediate-pressure cylinder of turbine (2-1) through the third valve (1-4) to do work, and the exhaust steam of the intermediate-pressure cylinder of turbine (2-1) is divided into two paths, one for low-pressure industrial users and the other for heating, which enters the heating network heater to heat the heating network circulating water; Part of the reheated steam flows through the fifth valve (1-11) and enters the second pressure reducing device (1-12) and the second desuperheating device (1-13) in sequence. After pressure reduction and desuperheating, it is divided into two paths: one path supplies steam to medium-pressure industrial users, and the other path supplies steam for heating, which enters the heater of the heating network. The drain water from the heating network heater is returned to the low-temperature water tank (5-13) of the heat exchange system. After the heat exchange system is heated, it enters the high-temperature water tank (5-14) of the heat exchange system, and then enters the boiler (1-1) through the first water pump (1-14). The compression process of the compressed air energy storage system includes: the second clutch (2-5) is disengaged, and the first electric motor (2-6) does no work; the steam turbine (2-1) drives the first clutch (2-2) to operate, driving the first compressor (2-3) and the second compressor (2-4) to do work; wherein, air enters the first compressor (2-3) for compression, pressurization and temperature increase, and sequentially enters the first gas-molten salt heat exchanger (5-1) and the first gas-water heat exchanger (5-2) for heat exchange, and after cooling, it enters the second compressor (2-4) for compression; in the second compressor (2-4), the air is pressurized and heated, and sequentially enters the second gas-molten salt heat exchanger (5-3) and the second gas-water heat exchanger (5-4) for heat exchange, and after cooling, it enters the third compressor (2-7). The second electric motor (2-8) does work, driving the third compressor (2-7) to do work, further compressing the gas. After the gas is pressurized and heated, it enters the third gas-molten salt heat exchanger (5-5) and the third gas-water heat exchanger (5-6) for heat exchange. After cooling, the compressed air enters the gas storage tank (3) for storage. During the heat exchange process, the molten salt in the low-temperature molten salt tank (5-11) is transported to the first gas-molten salt heat exchanger (5-1), the second gas-molten salt heat exchanger (5-3), and the third gas-molten salt heat exchanger (5-5) by the molten salt pump (5-15). The low-temperature molten salt is heated to high-temperature molten salt by the heat of compression and returned to the high-temperature molten salt tank (5-12). Part of the heat of compression is stored in the high-temperature molten salt tank (5-12). The high-pressure low-temperature water in the low-temperature water tank (5-13) is transported to the first gas-water heat exchanger (5-2), the second gas-water heat exchanger (5-4), and the third gas-water heat exchanger (5-6) by the second water pump (5-16). After being heated, it is returned to the high-temperature water tank (5-14). Part of the heat of compression is stored in the high-temperature water tank (5-14). The expansion process includes: compressed air in the gas storage tank (3) enters the fourth gas-water heat exchanger (5-7) and the fourth gas-molten salt heat exchanger (5-8) in sequence to be heated and then enters the first expander (4-1) to do work. After being de-heated and depressurized, the compressed air then enters the fifth gas-water heat exchanger (5-9) and the fifth gas-molten salt heat exchanger (5-10) in sequence to be heated and then enters the second expander (4-2) to do work. After being de-heated and depressurized, it is discharged into the atmosphere. The first expander (4-1) and the second expander (4-2) do work to drive the generator (4-3) to generate electrical energy, which is then connected to the power grid.

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