Compressed air energy storage system coupled with coal-fired unit and operation method

Abstract

The invention discloses a compressed air energy storage system coupled with a coal-fired unit and an operation method, and belongs to the technical field of energy storage. The operation method comprises the following steps that feed water of the coal-fired unit is heated in a boiler to generate steam, part of the steam supplies heat to the outside after temperature and pressure reduction, and the other part of the steam enters a steam turbine to do work; the compression system is used for converting electric energy of a power grid or kinetic energy of a coal-fired unit turbine into gas pressure energy; the gas storage system is used for storing high-pressure gas; the expansion system is used for converting gas pressure energy output by the gas storage system into expansion machine kinetic energy to drive a generator to generate electricity; the heat exchange system is used for transferring compression heat generated by the compression system to a heat storage unit of the heat exchange system and heating high-pressure and low-temperature gas from the gas storage system into high-pressure and high-temperature gas through a high-temperature heat source of the heat storage unit. Existing equipment and systems of the coal-fired unit can be utilized, and finally the comprehensive conversion efficiency of the compressed air energy storage system is improved.

Description

Technical Field

[0001] The invention relates to a compressed air energy storage system coupled with a coal-fired unit and an operation method thereof, belonging to the technical field of energy storage. Background Art

[0002] Compressed air energy storage, as a long-term energy storage, has the characteristics of fast start and stop, long cycle life, and strong load adaptability. It has a wide range of applications in peak shaving and valley filling, new 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 lack of heat supply after the units are shut down. The current treatment methods for the lack of heat supply are mainly: 1) Replacement by existing heat sources in the surrounding area; 2) If there is no alternative heat source in the surrounding area, new electric boilers or coal-fired units can be built. The above two treatment methods can solve the problem of heating after the heating units are shut down, but they will also cause waste of equipment.

[0004] In order to solve the regional heating problem faced by the coal-fired units that are about to be shut down, the existing equipment is used as much as possible to increase the heating safety margin. At the same time, in view of the huge challenges brought by the gradual increase in the proportion of new energy to the power grid system with coal-fired thermal power units as the main power source structure, the idea of ​​coupling compressed air energy storage system and coal-fired units is proposed in the existing technology.

[0005] The existing technology increases the deep peak-shaving capability of the coal-fired unit and the conversion efficiency of the compressed air energy storage system by absorbing heat from the thermal system of the coal-fired unit to heat the expander intake air, thereby realizing the transfer of energy from the coal-fired unit to the compressed air energy storage system. 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 with a coal-fired unit and an operation method.

[0007] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions.

[0008] In a first aspect, the present invention provides a compressed air energy storage system coupled to a coal-fired unit, comprising: The thermal system of the coal-fired unit is used to heat the feed water in the boiler to generate steam. Part of the steam is cooled and decompressed to provide heat to the outside, and the other part of the steam enters the steam turbine to do work. The compression system uses the power of the grid or the steam turbine of the coal-fired unit to drive the compressor to do work and convert it into air pressure energy; A gas storage system for storing high-pressure gas generated by the compression system; An expansion system, used to convert the air pressure energy output by the gas storage system into expansion kinetic energy to drive the generator to generate electricity; The heat exchange system is used to transfer the compression heat of the compression system to the heat storage unit of the heat exchange system, and is also used to use the high-temperature heat source of the heat storage unit to heat the high-pressure and low-temperature air coming out of the gas storage system into high-pressure and high-temperature air.

[0009] Further, 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 temperature reducing device, a second temperature reducing device, and a steam-molten salt heat exchanger; The superheated steam output end of the boiler is connected to the first valve and the second valve through pipelines. The first valve is connected to the first pressure reducing device through a pipeline, the first pressure reducing device is respectively connected to the fourth valve and the first temperature reducing device through pipelines, the fourth valve is connected to the steam-molten salt heat exchanger through a pipeline, the first temperature reducing device and the steam-molten salt heat exchanger are respectively connected to the first check valve through pipelines, and the first check valve is connected to the reheating system of the boiler through a pipeline. The second valve is connected to the high-pressure cylinder of the steam turbine through a pipeline to perform work, and after the work is performed, the steam enters the boiler reheat system through the second check valve; The reheated steam at the outlet of the reheat system of the boiler is connected to the third valve and the fifth valve through pipelines respectively. The third valve is connected to the intermediate pressure cylinder of the steam turbine through a pipeline to perform work. The low-pressure steam after the work in the intermediate pressure cylinder is supplied to the low-pressure heat source user. The fifth valve is connected to the second pressure reducing device and the second temperature reducing device in sequence through pipelines to supply steam to the medium-pressure heat source users.

[0010] Further, the compression system includes: a steam turbine, a first clutch, a second clutch, a first motor, a second motor, a first compressor, a second compressor and a third compressor; 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; The steam turbine, the first clutch, the first compressor, the second compressor, the second clutch, and the first motor are connected in sequence, and the third compressor is connected to the second motor; The first compressor, the second compressor and the third compressor are connected to the heat exchange system through pipelines.

[0011] Furthermore, the gas storage system is a gas storage reservoir, and the gas storage reservoir is connected to the heat exchange system through a pipeline.

[0012] Further, the expansion system comprises: a first expander, a second expander and a generator connected in sequence; The first expander and the second expander are respectively connected to the heat exchange system through pipelines.

[0013] Further, 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; Air enters the air inlet of the first-stage compressor, and the compressed gas at the outlet of the first-stage compressor is connected to the first air-molten salt heat exchanger and the first air-water heat exchanger of the first air-molten salt heat exchange system in sequence through a pipeline, and the compressed gas at the outlet of the first air-water heat exchanger is connected to the air inlet of the second compressor through a pipeline, and the compressed gas at the outlet of the second compressor is connected to the second air-molten salt heat exchanger and the second air-water heat exchanger of the second air-molten salt heat exchange system in sequence through a pipeline, and the compressed gas at the outlet of the second air-water heat exchanger is connected to the air inlet of the third compressor through a pipeline, and the third compressor is connected to the third air-molten salt heat exchanger and the third air-water heat exchanger of the third air-molten salt heat exchange system in sequence through a pipeline, and the compressed gas at the outlet of the third air-water heat exchanger is connected to the gas storage reservoir through a pipeline, The gas storage reservoir and the first expander are connected via a fourth gas-water heat exchanger and a fourth gas-molten salt heat exchanger of a fourth gas-molten salt heat exchange system; The first expander is connected to the second expander via a fifth gas-water heat exchanger and a fifth gas-molten salt heat exchanger of a fifth gas-molten salt heat exchange system; The low-temperature molten salt tank is respectively 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 through a molten salt pump and a pipeline, and then connected to the high-temperature molten salt tank through a pipeline; 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 through pipelines, and then connected to the high-temperature molten salt tank through pipelines; 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 through the second water pump and the pipeline, and then connected to the high-temperature water tank through the pipeline; The high-temperature water tank is connected to the fourth gas-water heat exchange system and the fifth gas-water heat exchange system through pipelines, and then connected to the low-temperature water tank through pipelines; The high temperature water tank is also connected to the boiler through the first water pump and pipelines.

[0014] In a second aspect, the present invention further provides an operation method of a compressed air energy storage system coupled to a coal-fired unit based on the first aspect, comprising: Working condition 1: The compressed air energy storage system operates alone. The operating process of working condition 1 is as follows: The compression process includes: the first clutch is disengaged, the steam turbine does not work, electricity is taken from the power grid, the first motor and the second motor are running, and the second clutch is closed and running. The first motor drives the first compressor and the second compressor, and the second motor drives the third compressor; The gas enters the first compressor to be compressed, and the compressed gas with increased pressure and temperature 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 the compressed gas after temperature reduction enters the second compressor for compression, and the compressed gas with increased pressure and temperature in the second compressor 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 the compressed gas after temperature reduction enters the third compressor for compression, and the compressed gas with increased pressure and temperature in the third compressor sequentially 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, and the compressed gas after temperature reduction enters the gas storage reservoir for storage; During the whole 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 through the molten salt pump, and then returned to the high-temperature molten salt tank after being heated, and part of the compression heat is stored in the molten salt tank; The high-pressure low-temperature water in the low-temperature 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 through the third water pump, and is returned to the high-temperature water tank after being heated, and part of the compression heat is stored in the high-temperature water tank; The expansion process includes: the compressed air in the gas storage reservoir enters the fourth gas-water heat exchanger and the fourth gas-molten salt heat exchanger of the fourth gas-molten salt heat exchange system in turn to be heated and heated, enters the first expander to perform work, and the compressed air after cooling and pressure reduction enters the fifth gas-water heat exchanger and the fifth gas-molten salt heat exchanger of the fifth heat exchange system in turn to be heated and heated, enters the second expander to perform work, and is discharged into the atmosphere after cooling and pressure reduction. The first expander and the second expander work to drive the generator to generate electricity, which is connected to the power grid.

[0015] Furthermore, it also includes: working condition 2, in the non-heating season, the coal-fired unit is used as a steam boiler for industrial steam supply. The operation process of working condition 2 is: The superheated steam outputted by the boiler flows through the first valve, and after passing through the first pressure reducing device and the first temperature reducing device, the temperature and pressure are reduced. When the steam parameters are the same as the exhaust steam parameters of the high-pressure cylinder during normal operation of the coal-fired unit, the steam enters the boiler reheating system after passing through the first check valve; After being heated, the reheated steam enters the fifth valve, the second pressure reducing device and the second temperature reducing device in turn. After temperature and pressure reduction, the steam parameters meet the needs of industrial users and steam is supplied to industrial users. During operation, the second valve, the third valve, the fourth valve and the second check valve in the coal-fired unit system are all in a closed state.

[0016] Furthermore, it also includes: working condition three, non-heating season, the operating condition of the industrial steam supply of the coal-fired unit coupled with the compressed air energy storage system, the operating process of working condition three is: The industrial steam supply process on the coal-fired unit side includes: the 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 perform work, and after being reduced in temperature and pressure, enters the boiler reheat system through the second check valve to be heated and heated, and part of the reheated steam enters the intermediate-pressure cylinder of the steam turbine through the third valve to perform work, and the exhaust steam of the intermediate-pressure cylinder supplies steam to low-pressure heat source users; part of the reheated steam flows through the fifth valve, enters the second pressure reducing device and the second temperature reducing device in turn, and after being reduced in pressure and temperature, supplies steam to industrial steam users of medium-pressure heat sources; The compression process of the compressed air energy storage system includes: the second clutch is disconnected, and the first motor does not work; the steam turbine drives the first clutch to operate, driving the first compressor and the second compressor to work; wherein, the air enters the first compressor for compression, increases pressure and temperature, and 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 in sequence, and enters the second compressor for compression after cooling; increases pressure and temperature in the second compressor, and 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 in sequence, and enters the third compressor after cooling; The second motor performs work to drive the third compressor to perform work. After the pressure and temperature are increased, the compressed air 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 the temperature is reduced, the compressed air enters the gas storage reservoir for storage. During the heat exchange process of 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, 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 a molten salt pump, the low-temperature molten salt is heated into high-temperature molten salt by compression heat, and returned to the high-temperature molten salt tank, and part of the compression heat is stored in the high-temperature molten salt tank; the low-temperature water in the low-temperature 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 a second water pump, and returned to the high-temperature water tank after being heated, and part of the compression heat is stored in the high-temperature water tank; The expansion process includes: the compressed air in the gas storage reservoir enters the fourth gas-water heat exchanger and the fourth gas-molten salt heat exchanger of the fourth gas-molten salt heat exchange system in turn to be heated and heated, enters the first expander to perform work, and the compressed air after cooling and pressure reduction enters the fifth gas-water heat exchanger and the fifth gas-molten salt heat exchanger of the fifth heat exchange system in turn to be heated and heated, enters the second expander to perform work, and is discharged into the atmosphere after cooling and pressure reduction. The first expander and the second expander drive the generator to generate electricity during the work, and are connected to the power grid.

[0017] Furthermore, in the third working condition, the first valve in the coal-fired unit system is opened, so that part of the main steam is decompressed through the first decompression device, and after flowing through the fourth valve, the steam exchanges heat in the steam-molten salt heat exchanger to heat the molten salt to a higher temperature; After the temperature and pressure are reduced, the steam enters the valve and then enters the boiler reheating system to be heated. If the molten salt temperature has reached the preset high temperature, the first valve is closed.

[0018] Furthermore, it also includes: working condition 4, heating season, coal-fired unit industry, heating steam supply coupled compressed air energy storage system operating conditions, the operating process of working condition 4 is: 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: the 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 perform work, and after being reduced in temperature and pressure, enters the boiler reheating system through the second check valve to be heated and heated, and part of the reheated steam enters the intermediate-pressure cylinder of the steam turbine through the third valve to perform work, and the exhaust steam of the intermediate-pressure cylinder of the steam turbine is divided into two paths, one for supplying steam to low-pressure industrial users, and the other for supplying steam for heating, and enters the heating network heater to heat the circulating water of the heating network; Part of the reheated steam flows through the fifth valve and enters the second pressure reducing device and the second temperature reducing device in sequence. After pressure reducing and temperature reducing, it is divided into two paths, one for medium-pressure industrial users and the other for heating, and enters the heating network heater. The water from the heating network heater is drained back to the low-temperature water tank of the heat exchange system. After the heat exchange system is heated up, it enters the high-temperature water tank of the heat exchange system, and then enters the boiler through the first water pump group; The compression process of the compressed air energy storage system includes: the second clutch is disconnected, and the first motor does not work; the steam turbine drives the first clutch to operate, driving the first compressor and the second compressor to work; wherein, the gas enters the first compressor for compression, increases 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 enters the second compressor for compression after cooling; increases pressure and temperature in the second compressor, 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 enters the third compressor after cooling; The second motor works to drive the third compressor to work, further compressing the air, increasing the pressure and temperature of the compressed air, and then entering 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, and then entering the gas storage reservoir for storage after the temperature is reduced; During the heat exchange process of 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, 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 a molten salt pump, the low-temperature molten salt is heated into high-temperature molten salt by compression heat, and returned to the high-temperature molten salt tank, and part of the compression heat is stored in the high-temperature molten salt tank; the high-pressure and low-temperature water in the low-temperature 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 a second water pump, and returned to the high-temperature water tank after being heated, and part of the compression heat is stored in the high-temperature water tank; The expansion process includes: the compressed air in the gas storage reservoir enters the fourth gas-water heat exchanger and the fourth gas-molten salt heat exchanger of the fourth gas-molten salt heat exchange system in turn to be heated and heated, enters the first expander to perform work, and the compressed air after cooling and pressure reduction enters the fifth gas-water heat exchanger and the fifth gas-molten salt heat exchanger of the fifth heat exchange system in turn to be heated and heated, enters the second expander to perform work, and is discharged into the atmosphere after cooling and pressure reduction. The first expander and the second expander work to drive the generator to generate electricity, which is connected to the power grid.

[0019] The beneficial effects achieved by the present invention are: The present invention can realize the utilization of existing equipment and systems of coal-fired units; solve the problems of industrial steam supply and heating faced by some areas after the shutdown of coal-fired units; while ensuring industrial steam supply and heating, use the work of the steam turbine to drive the compressor to work, extract steam to heat molten salt, and realize the increase of the inlet temperature of the expander, and finally realize the improvement of the comprehensive conversion efficiency of the compressed air energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the system principle of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0024] Embodiment 1: This embodiment introduces a compressed air energy storage system coupled with a coal-fired unit, comprising: The thermal system of the coal-fired unit is used to heat the feed water in the boiler to generate steam. Part of the steam is cooled and decompressed to provide heat to the outside; part of the steam enters the steam turbine to do work, driving the compressor to do work and compress the air.

[0025] The compression system is used to drive the compressor to work through a steam turbine or motor, and compress the air in the ambient atmosphere into high-pressure air through a step-by-step compression method, and store it in the gas storage system. That is, the electrical energy of the power grid or the steam energy of the coal-fired unit is converted into air energy and stored.

[0026] The gas storage system is used to store the high-pressure air generated by the compression system in the gas storage reservoir, and when the expander needs to do work, the high-pressure gas is delivered to the expansion system.

[0027] The expansion system is used to transport the high-pressure air energy in the gas storage system to the expander in the expansion system, and use the high-temperature and high-pressure air to drive the expansion turbine to do work, thereby converting the air energy into kinetic energy and driving the generator to generate electricity.

[0028] Heat exchange system, in the compressor work project, the compressor exhaust is high-pressure, high-temperature air. In order to improve the work efficiency of the next-stage compressor, the high-pressure, high-temperature air needs to be cooled into 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 compression heat 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.

[0029] 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 temperature reducing device 1-7, a second temperature reducing 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 through a pipeline, the first pressure reducing device 1-5 is connected to the fourth valve 1-6 and the first temperature reducing device 1-7 through pipelines, the fourth valve 1-6 is connected to the steam-molten salt heat exchanger 1-8 through a pipeline, the first temperature reducing device 1-7 and the steam-molten salt heat exchanger 1-8 are connected to the first check valve 1-9 through pipelines, and the first check valve 1-9 is connected to the reheat system of the boiler 1-1 through a pipeline. The second valve 1-3 is connected to the compression system through a pipeline to perform high-pressure work, and the desuperheated and reduced-pressure steam after the high-pressure work enters the reheating system of the boiler 1-1 through the second check valve 1-10; The reheat steam output end of the reheat system of the boiler 1-1 is connected to the third valve 1-4 and the fifth valve 1-11 through pipelines. The third valve 1-4 is connected to the compression system through a pipeline to perform medium-pressure work. The low-pressure steam after the medium-pressure work is used to supply steam to the low-pressure heat source users. The fifth valve 1-11 is connected to the second pressure reducing device 1-12 and the second temperature reducing device 1-13 in sequence through pipelines to supply steam to the medium-pressure heat source users.

[0030] The compression system includes: a steam turbine 2-1, a first clutch 2-2, a second clutch 2-5, a first motor 2-6, a second 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 medium-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 motor 2-6 are connected in sequence, and the third compressor 2-7 and the second 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 through pipelines.

[0031] The gas storage system is a gas storage reservoir 3, and the gas storage reservoir 3 is connected to the heat exchange system through a pipeline.

[0032] The expansion system comprises: 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.

[0033] 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; The air inlet of the first-stage compressor 2-3 is connected to the gas, and the first-stage compressor 2-3 is connected to the first air-molten salt heat exchanger 5-1 and the first air-water heat exchanger 5-2 of the first air-molten salt heat exchange system in sequence through pipelines. The first air-water heat exchanger 5-2 is connected to the air inlet of the second compressor 2-4 through a pipeline. The second compressor 2-4 is connected to the second air-molten salt heat exchanger 5-3 and the second air-water heat exchanger 5-4 of the second air-molten salt heat exchange system in sequence through pipelines. The second air-water heat exchanger 5-4 is connected to the air inlet of the third compressor 2-7 through a pipeline. The third compressor 2-7 is connected to the third air-molten salt heat exchanger 5-5 and the third air-water heat exchanger 5-6 of the third air-molten salt heat exchange system in sequence through pipelines. The third air-water heat exchanger 5-6 is connected to the gas storage reservoir 3 through a pipeline. The gas storage reservoir 3 is connected to the first expander 4-1 through a fourth gas-water heat exchanger 5-7 and a fourth gas-molten salt heat exchanger 5-8 of a fourth gas-molten salt heat exchange system; The first expander 4-1 is connected to the second expander 4-2 via a fifth gas-water heat exchanger 5-9 and a fifth gas-molten salt heat exchanger 5-10 of a fifth gas-molten salt heat exchange system; The low-temperature 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 through the molten salt pump 5-15 and the pipeline; The high-temperature molten salt tanks 5-12 are respectively 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 through pipelines; 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 through the second water pump 5-16 and the pipeline; The high temperature water tanks 5-14 are respectively 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 through pipelines; The high temperature water tank 5-14 is also connected to the boiler 1-1 through the first water pump 1-14 and the pipeline.

[0034] Embodiment 2 is based on the same inventive concept as Embodiment 1. This embodiment introduces an operation method of a compressed air energy storage system coupled to a coal-fired unit, including: Working condition 1: The compressed air energy storage system operates alone. The operating process of working condition 1 is as follows: The compression process includes: the first clutch 2-2 is separated, the steam turbine 2-1 does not work, draws power from the power grid, the first motor 2-6 and the second motor 2-8 are running, and the second clutch 2-5 is closed and running. The first motor 2-6 drives the first compressor 2-3 and the second compressor 2-4, and the motor 2-8 drives the third compressor 2-7; The air enters the first compressor 2-3 to be compressed, and the compressed gas with increased pressure and temperature 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, and the compressed gas after temperature reduction enters the second compressor 2-4 for compression, and the compressed gas with increased pressure and temperature in the second compressor 2-4 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, and the compressed gas after temperature reduction enters the third compressor 2-7 for compression, and the compressed gas with increased pressure and temperature in the third compressor 2-7 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, and the compressed gas after temperature reduction enters the gas storage reservoir 3 for storage; During the whole 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 through the molten salt pump, and is returned to the high-temperature molten salt tank 5-12 after being heated, and part of the compression heat is stored in the molten salt tank; 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 through the second water pump 5-16, and is returned to the high-temperature water tank 5-14 after being heated, and part of the compression heat is stored in the high-temperature water tank 5-14; The expansion process includes: the compressed air in the gas storage reservoir 3 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 in turn to be heated and heated, and enters the first expander 4-1 to perform work. The compressed air after cooling and pressure reduction 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 in turn to be heated and heated, and enters the second expander 4-2 to perform work, and is discharged into the atmosphere after cooling and pressure reduction. During the work of the first expander 4-1 and the second expander 4-2, the generator 4-3 is driven to generate electricity, which is connected to the power grid.

[0035] It also includes: Operating Condition 2, 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: The superheated steam outputted by 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 temperature reducing device 1-7, the superheated steam is desuperheated and depressurized. When the steam parameters are the same as the exhaust steam parameters of the high-pressure cylinder during normal operation of the coal-fired unit, the steam 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 temperature reducing device 1-13 in turn. After the temperature 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 a closed state.

[0036] It also includes: Condition 3, non-heating season, coal-fired unit industrial steam supply coupled compressed air energy storage system operation condition, the operation process of Condition 3 is: The industrial steam supply process on the coal-fired unit side includes: the superheated steam generated by the boiler 1-1 enters the main steam pipeline, the main steam flows through the second valve 1-3 and enters the high-pressure cylinder of the turbine 2-1 to perform work, and after being reduced in temperature and pressure, enters the boiler 1-1 reheat system through the second check valve 1-10 to be heated and heated, and part of the reheated steam enters the medium-pressure cylinder of the turbine 2-1 through the third valve 1-4 to perform work, and the exhaust steam of the medium-pressure cylinder is used to supply steam to low-pressure heat source 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 temperature reducing device 1-13 in turn, and after being reduced in pressure and temperature, it is supplied to industrial steam users of medium-pressure heat sources; The compression process of the compressed air energy storage system includes: the second clutch 2-5 is disconnected, and the first motor 2-6 does not 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 work; wherein, the gas enters the first compressor 2-3 for compression, increases pressure and temperature, and 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, and enters the second compressor 2-4 for compression after cooling; increases pressure and temperature in the second compressor 2-4, 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, and enters the third compressor 2-7 after cooling; The second motor 2-8 performs work, driving 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, and then enter the gas storage reservoir 3 for storage after the temperature is reduced; During the heat exchange process of 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, 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 through the molten salt pump 5-15, and is returned to the high-temperature molten salt tank 5-12 after being heated, and part of the compression heat is stored in the high-temperature molten salt tank 5-12; the high-pressure and 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 through the second water pump 5-16, and is returned to the high-temperature water tank 5-14 after being heated, and part of the compression heat is stored in the high-temperature water tank 5-14; The expansion process includes: the compressed air in the gas storage reservoir 3 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 in turn to be heated and heated, and enters the first expander 4-1 to perform work. The compressed air after cooling and pressure reduction 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 in turn to be heated and heated, and enters the second expander 4-2 to perform work, and is discharged into the atmosphere after cooling and pressure reduction. The first expander 4-1 and the second expander 4-2 perform work to drive the generator 4-3 to generate electricity, which is connected to the power grid.

[0037] In working condition 3, the first valve 1-2 in the coal-fired unit system is opened, so that part of the main steam is decompressed through the first decompression device 1-5, and after flowing through the fourth valve 1-6, the steam exchanges heat in the steam-molten salt heat exchanger 1-8 to heat the molten salt to a higher temperature; After the temperature and 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.

[0038] It also includes: Condition 4, heating season, coal-fired unit industrial, heating steam supply coupled compressed air energy storage system operation conditions, the operation process of Condition 4 is: 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: the superheated steam generated by the boiler 1-1 enters the main steam pipeline, the main steam flows through the second valve 1-3 and enters the high-pressure cylinder of the steam turbine 2-1 to perform work, and after being reduced in temperature and pressure, enters the boiler 1-1 reheat system through the second check valve 1-10 to be heated and heated, and part of the reheated steam enters the medium-pressure cylinder of the steam turbine 2-1 through the third valve 1-4 to perform work, and the exhaust steam of the medium-pressure cylinder is divided into two paths, one for low-pressure industrial steam supply, and the other for heating steam supply, and enters the heating network heater; Part of the reheated steam flows through the fifth valve 1-11, and enters the second pressure reducing device 1-12 and the second temperature reducing device 1-13 in sequence. After pressure reduction and temperature reduction, it is divided into two paths, one for medium-pressure industrial steam supply, and the other for heating steam supply, and enters the heating network heater; The water from the heating network heater is drained back to the low-temperature water tank 5-13 of the heat exchange system, and after the heat exchange system is heated up, 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 group 1-14; The compression process of the compressed air energy storage system includes: the second clutch 2-5 is disconnected, and the first motor 2-6 does not 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 work; wherein, the gas enters the first compressor 2-3 for compression, increases pressure and temperature, and 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, and enters the second compressor 2-4 for compression after cooling; increases pressure and temperature in the second compressor 2-4, 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, and enters the third compressor 2-7 after cooling; The second motor 2-8 performs work, driving 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, and then enter the gas storage reservoir 3 for storage after the temperature is reduced; During the heat exchange process of 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, 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 through the molten salt pump 5-15, and is returned to the high-temperature molten salt tank 5-12 after being heated, and part of the compression heat is stored in the high-temperature molten salt tank 5-12; the high-pressure and 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 through the second water pump 5-16, and is returned to the high-temperature water tank 5-14 after being heated, and part of the compression heat is stored in the high-temperature water tank 5-14; The expansion process includes: the compressed air in the gas storage reservoir 3 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 in turn to be heated and heated, and enters the first expander 4-1 to perform work. The compressed air after cooling and pressure reduction 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 in turn to be heated and heated, and enters the second expander 4-2 to perform work, and is discharged into the atmosphere after cooling and pressure reduction. The first expander 4-1 and the second expander 4-2 perform work to drive the generator 4-3 to generate electricity, which is connected to the power grid.

[0039] Embodiment 3 is based on the same inventive concept as Embodiment 1. This embodiment introduces a compressed air energy storage system coupled to a coal-fired unit, including: 1) Thermal system of coal-fired unit, including: 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 temperature reducing device 1-7, second temperature reducing device 1-13, steam-molten salt heat exchanger 1-8 and associated steam and water pipelines; 2) Compression system, including: steam turbine 2-1, first clutch 2-2, second clutch 2-5, first motor 2-6, second motor 2-8, first compressor 2-3, second compressor 2-4 and third compressor 2-7; 3) The gas storage system is gas storage 3; 4) An expansion system, comprising: a first expander 4-1, a second expander 4-2 and a generator 4-3; 5) 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.

[0040] Working conditions include: (I) Independent operation condition of compressed air energy storage system: The coal-fired unit is in shutdown state, and the compressed air energy storage system operates as an independent power station.

[0041] Compression process: The first clutch 2-2 is disengaged, and the steam turbine does not work. Power is taken from the grid, the first motor 2-6 and the second motor 2-8 are running, the second clutch 2-5 is closed and running, 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. The air enters the first compressor 2-3 and is compressed, and the pressure and temperature are increased. The compressed air 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 in turn for heat exchange. After cooling, the compressed air enters the second compressor 2-4 for compression; the pressure and temperature are increased again in the second compressor, and the compressed air 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 in turn for heat exchange. After cooling, the compressed air enters the third compressor 2-7 for compression; the pressure and temperature are increased in the third compressor, and the compressed air 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 in turn for heat exchange. After cooling, the compressed air enters the gas storage reservoir 3 for storage. During the entire heat exchange process, the molten salt in the low-temperature molten salt tank 5-11 is transported to the heat exchange system through the molten salt pump 5-15, and is returned to the high-temperature molten salt tank 5-12 after being heated, and part of the compression 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 through the second water pump 5-16, and is returned to the high-temperature water tank 5-14 after being heated, and part of the compression heat is stored in the high-temperature water tank 5-14.

[0042] Expansion process: The compressed air in the gas storage 3 enters the fourth gas-water heat exchanger 5-7 and the fourth gas-molten salt heat exchanger 5-8 of the heat exchange system in turn to be heated and heated, and then enters the first expander 4-1 to perform work; the compressed air after temperature reduction and pressure reduction then enters the fifth gas-water heat exchanger 5-9 and the fifth gas-molten salt heat exchanger 5-10 of the heat exchange system in turn to be heated and heated, then enters the second expander 4-2 to perform work, and then is discharged into the atmosphere after temperature reduction and pressure reduction. During the work of the expander, the generator 4-3 is driven to generate electric energy, which is then fed into the power grid.

[0043] In the non-heating season, coal-fired units are used as steam boilers for industrial steam supply. Under this operating condition, the compressed air energy storage system is in a shutdown state, the coal-fired unit is only used as a heating boiler for industrial steam supply, and the steam does not enter the turbine to perform work.

[0044] The superheated steam at the outlet of boiler 1-1 flows through the first valve 1-2, the first pressure reducing device 1-5, and the first temperature reducing device 1-7. The superheated steam is reduced in temperature and pressure. When the steam parameters are basically the same as the exhaust parameters of the high-pressure cylinder during normal operation of the coal-fired unit, the steam enters the boiler reheating system after 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 temperature reducing device 1-13. After the steam parameters are reduced in temperature and pressure, they meet the needs of industrial users and are supplied to industrial users.

[0045] During this operating condition, 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. Because industrial steam is supplied to the outside, the water supply flow of the original water supply system of the coal-fired unit needs to meet the system requirements; part of the reheated steam after temperature reduction and pressure reduction can be used to heat and condense water to meet the boiler's requirements for water inlet parameters.

[0046] (III) In the non-heating season, the industrial steam supply of coal-fired units coupled with the compressed air energy storage system operates as follows: In the non-heating season, coal-fired units need to supply industrial steam to the outside and drive the steam turbine to operate.

[0047] Industrial steam supply process of coal-fired units and compression process of compressed air energy storage system: Industrial steam supply process on the coal-fired unit side: the superheated steam generated by boiler 1-1 enters the main steam pipeline, the main steam flows through the second valve 1-3 and enters the high-pressure cylinder of turbine 2-1 to perform work, and after being reduced in temperature and pressure, enters the reheat system of boiler 1-1 through the second check valve 1-10 to be heated and heated. Part of the reheated steam enters the medium-pressure cylinder of turbine 2-1 through the third valve 1-4 to perform work, and the exhaust steam of the medium-pressure cylinder can supply steam to low-pressure heat source 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 temperature reducing device 1-13 (water spray temperature reducing system) in turn, and after being reduced in pressure and temperature, it is supplied to industrial steam users of medium-pressure heat source.

[0048] The compression process of the compressed air energy storage system: the second clutch 2-5 is disconnected, and the first motor 2-6 does not 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 work. Among them, the air enters the first compressor 2-3 for compression, pressure and temperature increase, and 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 in turn, and enters the second compressor 2-4 for compression after cooling; the air is pressure and temperature increased in the second compressor, and 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 in turn, and enters the third compressor 2-7 after cooling. The second motor 2-8 works, driving the third compressor 2-7 to compress, pressure and temperature increase, and 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 in turn, and enters the gas storage reservoir 3 for storage after cooling. During the entire heat exchange process, the molten salt in the low-temperature molten salt tank 5-11 is transported to the heat exchange system through the molten salt pump 5-15, and is returned to the high-temperature molten salt tank 5-12 after being heated, and part of the compression 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 through the second water pump 5-16, and is returned to the high-temperature water tank 5-14 after being heated, and part of the compression heat is stored in the high-temperature water tank 5-14.

[0049] In order to increase the inlet temperature of the expander, the first valve 1-2 in the coal-fired unit system can also be opened to reduce the pressure of part of the main steam through 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 to heat the molten salt to a higher temperature to improve the inlet parameters of the expander. After the temperature and pressure reduction, the steam enters the first check valve 1-9 and then enters the boiler 1-1 reheating system to be heated and heated. If the molten salt temperature is high enough, the first valve 1-2 can be closed.

[0050] Expansion process: This process is the same as when the compressed air energy storage system is running alone, but because the main steam of the coal-fired unit heats the molten salt, the expander inlet temperature can be heated to a higher parameter, and the expander efficiency is increased. Under the premise that the expander inlet flow rate remains unchanged, 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.

[0051] (IV) During the heating season, the coal-fired units need to supply industrial and heating steam to the compressed air energy storage system: During the heating season, the coal-fired units need to supply industrial and heating steam to the outside world and drive the steam turbine to operate.

[0052] Industrial steam supply process of coal-fired units and compression process of compressed air energy storage system: 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 process of the industrial steam supply coupled compressed air energy storage system of the coal-fired unit in the non-heating season (III). The difference is that The steam exhaust from the medium-pressure cylinder of the steam turbine 2-1 can be divided into two routes, one for low-pressure industrial steam supply and the other for heating steam supply, entering the heating network heater. The steam from the outlet of the reheating system of the boiler 1-1 to the second desuperheating device 1-13 can also be divided into two routes, one for medium-pressure industrial steam supply and the other for heating steam supply, entering the heating network heater.

[0053] The drainage water from the heating network heater returns to the low-temperature water tank 5-13 of the heat exchange system, and enters the high-temperature water tank 5-14 after being heated in the heat exchange system, and then enters the boiler 1-1 system through the first water pump 1-14.

[0054] Compression process of compressed air energy storage system: This process is consistent with the operating conditions of the industrial steam supply coupled compressed air energy storage system of coal-fired units in the non-heating season (III).

[0055] 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 in the non-heating season (III).

[0056] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented 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.

[0057] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0058] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0059] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A compressed air energy storage system coupled with a coal-fired unit, characterized in that: include: The thermal system of the coal-fired unit is used to heat the feed water in the boiler to generate steam. Part of the steam is cooled and decompressed to provide heat to the outside, and the other part of the steam enters the steam turbine to do work. The compression system uses the power from the grid or the steam turbine of a coal-fired unit to drive the compressor to do work and convert it into air pressure energy; A gas storage system for storing high-pressure gas generated by the compression system; An expansion system, used to convert the air pressure energy output by the gas storage system into expansion kinetic energy to drive the generator to generate electricity; The heat exchange system is used to transfer the compression heat generated by the compression system to the heat storage unit of the heat exchange system, and is also used to use the high-temperature heat source of the heat storage unit to heat the high-pressure and low-temperature gas coming out of the gas storage system into high-pressure and high-temperature gas.

2. The compressed air energy storage system coupled with a coal-fired unit according to claim 1, characterized in that: The thermal system of the coal-fired unit comprises: 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 temperature reducing device (1-7), a second temperature reducing 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) through a pipeline, the first pressure reducing device (1-5) is respectively connected to the fourth valve (1-6) and the first temperature reducing device (1-7) through pipelines, the fourth valve (1-6) is connected to the steam-molten salt heat exchanger (1-8) through a pipeline, the first temperature reducing device (1-7) and the steam-molten salt heat exchanger (1-8) are respectively connected to the first check valve (1-9) through pipelines, and the first check valve (1-9) is connected to the reheat system of the boiler (1-1) through a pipeline. The second valve (1-3) is connected to the high-pressure cylinder of the steam turbine through a pipeline to perform work, and after the work is performed, the steam enters the reheating system of the boiler (1-1) through the second check valve (1-10); The reheated steam at the outlet of the reheat system of the boiler (1-1) is connected to the third valve (1-4) and the fifth valve (1-11) through pipelines, respectively. The third valve (1-4) is connected to the intermediate pressure cylinder of the steam turbine through a pipeline to perform work. The low-pressure steam after the work in the intermediate pressure cylinder supplies steam to the low-pressure heat source user. The fifth valve (1-11) is connected in sequence to the second pressure reducing device (1-12) and the second temperature reducing device (1-13) through pipelines to supply steam to the medium-pressure heat source user.

3. The compressed air energy storage system coupled with a coal-fired unit according to claim 2, characterized in that: The compression system comprises: a steam turbine (2-1), a first clutch (2-2), a second clutch (2-5), a first motor (2-6), a second 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 medium-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 motor (2-6) are connected in sequence, and the third compressor (2-7) is connected to the second motor (2-8); The first compressor (2-3), the second compressor (2-4) and the third compressor (2-7) are connected to the heat exchange system through pipelines.

4. The compressed air energy storage system coupled with a coal-fired unit according to claim 3, characterized in that: The gas storage system is a gas storage reservoir (3), and the gas storage reservoir (3) is connected to the heat exchange system via a pipeline; The expansion system comprises: 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 via pipelines.

5. The compressed air energy storage system coupled with a coal-fired unit according to claim 4, characterized in that: The heat exchange system comprises: 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 air inlet of the first-stage compressor (2-3), the compressed gas at the outlet of the first-stage compressor (2-3) is connected in sequence to the first air-molten salt heat exchanger (5-1) and the first air-water heat exchanger (5-2) of the first air-molten salt heat exchange system through a pipeline, the compressed air at the outlet of the first air-water heat exchanger (5-2) is connected to the air inlet of the second compressor (2-4) through a pipeline, the compressed air at the outlet of the second compressor (2-4) is connected in sequence to the second air-molten salt heat exchanger (5-3) and the second air-water heat exchanger (5-4) of the second air-molten salt heat exchange system through a pipeline, the compressed air at the outlet of the second air-water heat exchanger (5-4) is connected to the air inlet of the third compressor (2-7) through a pipeline, the third compressor (2-7) is connected in sequence to the third air-molten salt heat exchanger (5-5) and the third air-water heat exchanger (5-6) of the third air-molten salt heat exchange system through a pipeline, the compressed air at the outlet of the third air-water heat exchanger (5-6) is connected to the gas storage reservoir (3) through a pipeline, The gas storage reservoir (3) and the first expander (4-1) are connected via a fourth gas-water heat exchanger (5-7) and a fourth gas-molten salt heat exchanger (5-8) of a fourth gas-molten salt heat exchange system; The first expander (4-1) and the second expander (4-2) are connected via a fifth gas-water heat exchanger (5-9) and a fifth gas-molten salt heat exchanger (5-10) of a fifth gas-molten salt heat exchange system; The low-temperature molten salt tank (5-11) is respectively 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 through a molten salt pump (5-15) and a pipeline, and is then connected to the high-temperature molten salt tank (5-12) through a pipeline; The high-temperature molten salt tank (5-12) is connected to the fourth gas-molten salt heat exchange system and the fifth gas-molten salt heat exchange system through pipelines, and then connected to the high-temperature molten salt tank (5-11) through pipelines; The low-temperature water tank (5-13) is respectively connected to the first gas-water heat exchange system, the second gas-water heat exchange system, and the third gas-water heat exchange system through the second water pump (5-16) and the pipeline, and is then connected to the high-temperature water tank (5-14) through the pipeline; The high-temperature water tank (5-14) is connected to the fourth gas-water heat exchange system and the fifth gas-water heat exchange system through pipelines, and is then connected to the low-temperature water tank (5-13) through pipelines; The high temperature water tank (5-14) is also connected to the boiler (1-1) via the first water pump (1-14) and a pipeline.

6. An operating method of a compressed air energy storage system coupled to a coal-fired unit according to claim 5, characterized in that: include: Working condition 1: The compressed air energy storage system operates alone. The operating process of working condition 1 is as follows: The compression process includes: the first clutch (2-2) is disengaged, the steam turbine (2-1) does not perform work, draws power from the power grid, the first motor (2-6) and the second motor (2-8) operate, and the second clutch (2-5) is closed and operated. The first motor (2-6) drives the first compressor (2-3) and the second compressor (2-4), and the second motor (2-8) drives the third compressor (2-7); a gas-molten salt heat exchange system The gas enters the first compressor (2-3) and is compressed. The compressed gas with increased pressure and temperature 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 the temperature is reduced, the compressed gas enters the second compressor (2-4) for compression. The compressed gas with increased pressure and temperature in the second compressor (2-4) 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 the temperature is reduced, the compressed gas enters the third compressor (2-7) for compression. The compressed gas with increased pressure and temperature in the third compressor (2-7) 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 the temperature is reduced, the compressed gas enters the gas storage reservoir (3) for storage. During the entire 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 through a molten salt pump, and is returned to the high-temperature molten salt tank (5-12) after being heated, and part of the compression heat is stored in the molten salt tank; 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 through the second water pump (5-16), and is returned to the high-temperature water tank (5-14) after being heated, and part of the compression heat is stored in the high-temperature water tank (5-14); The expansion process includes: the compressed air in the gas storage reservoir (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 heated, and then enters the first expander (4-1) to perform work. The compressed air after decompression and temperature reduction 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 heated, and then enters the second expander (4-2) to perform work. After decompression and temperature reduction, the compressed air is discharged into the atmosphere. The first expander (4-1) and the second expander (4-2) drive the generator (4-3) to generate electric energy, which is then connected to the power grid.

7. The operating method according to claim 6, characterized in that: Also includes: Working condition 2: In the non-heating season, the coal-fired unit is used as a steam boiler for industrial steam supply. The operation process of working condition 2 is as follows: The superheated steam outputted from the boiler (1-1) flows through the first valve (1-2), passes through the first pressure reducing device (1-5) and the first temperature reducing device (1-7), and the superheated steam is reduced in temperature and pressure. When the steam parameters are the same as the exhaust parameters of the high-pressure cylinder of the steam turbine (2-1) during normal operation of the coal-fired unit, the steam enters the boiler (1-1) reheat system 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 temperature reducing device (1-13) in sequence. After being reduced in temperature and pressure, the steam parameters meet the needs of industrial users, and steam is 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 a closed state.

8. The operating method according to claim 6, characterized in that: Also includes: Condition 3: In the non-heating season, the industrial steam supply of coal-fired units coupled with the compressed air energy storage system is operated. The operation process of Condition 3 is as follows: The industrial steam supply process at the coal-fired unit side includes: the superheated steam generated by the boiler (1-1) enters the main steam pipeline, the main steam flows through the second valve (1-3) into the high-pressure cylinder of the turbine (2-1) to perform work, and after being reduced in temperature and pressure, enters the boiler (1-1) reheat system through the second check valve (1-10) to be heated and heated, and part of the reheated steam enters the medium-pressure cylinder of the turbine (2-1) through the third valve (1-4) to perform work, and the exhaust steam of the medium-pressure cylinder is used to supply steam 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 temperature reducing device (1-13) in sequence, and after being reduced in pressure and temperature, 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 disconnected, and the first motor (2-6) does not 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 work; wherein the air enters the first compressor (2-3) for compression, increases pressure and temperature, and 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, and after cooling, enters the second compressor (2-4) for compression; the air increases pressure and temperature in the second compressor (2-4), and 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, and after cooling, enters the third compressor (2-7); The second motor (2-8) performs work to drive the third compressor (2-7) to perform work, and the compressed gas after pressure and temperature increase 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, and the compressed air after temperature reduction enters the gas storage reservoir (3) for storage; During the heat exchange process of 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, 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 through the molten salt pump (5-15), the low-temperature molten salt is heated into high-temperature molten salt by the compression heat, and returns to the high-temperature molten salt tank (5-12), and part of the compression heat 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 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 through the second water pump (5-16), and returns to the high-temperature water tank (5-14) after being heated, and part of the compression heat is stored in the high-temperature water tank (5-14); The expansion process includes: the compressed air in the gas storage reservoir (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 heated, and enters the first expander (4-1) to perform work. The compressed air after temperature reduction and pressure reduction 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 heated, and enters the second expander (4-2) to perform work. After temperature reduction and pressure reduction, the compressed air is discharged into the atmosphere. The first expander (4-1) and the second expander (4-2) perform work to drive the generator (4-3) to generate electric energy, which is then connected to the power grid.

9. The operating method according to claim 8, characterized in that: In working condition three, the first valve (1-2) in the coal-fired unit system is opened, so that part of the main steam is reduced in pressure through the first pressure reducing device (1-5), and after flowing 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; After the temperature and pressure reduction, the steam enters the valve (1-9) and then enters the boiler (1-1) reheating system to be heated and heated. If the molten salt temperature has reached a preset high temperature, the first valve (1-2) is closed.

10. The operating method according to claim 8, characterized in that: Also includes: Condition 4: Heating season, coal-fired units industrial, heating steam supply coupled compressed air energy storage system operation conditions, the operation process of condition 4 is: 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: the superheated steam generated by the boiler (1-1) enters the main steam pipeline, the main steam flows through the second valve (1-3) into the high-pressure cylinder of the steam turbine (2-1) to perform work, after being reduced in temperature and pressure, it enters the boiler (1-1) reheat system through the second check valve (1-10) to be heated and heated, part of the reheated steam enters the medium-pressure cylinder of the steam turbine (2-1) through the third valve (1-4) to perform work, and the exhaust steam of the medium-pressure cylinder of the steam turbine (2-1) is divided into two paths, one path is used to supply steam to low-pressure industrial users, and the other path is used to supply steam for heating and enters the heating network heater to heat the circulating water of the heating network; Part of the reheated steam flows through the fifth valve (1-11) and enters the second pressure reducing device (1-12) and the second temperature reducing device (1-13) in sequence. After pressure reduction and temperature reduction, the steam is divided into two paths, one path is used to supply steam to medium-pressure industrial users, and the other path is used to supply steam for heating and enters the heating network heater. The water from the heating network heater is drained back into the low-temperature water tank (5-13) of the heat exchange system, and after being heated in the heat exchange system, 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 group (1-14); The compression process of the compressed air energy storage system includes: the second clutch (2-5) is disconnected, and the first motor (2-6) does not 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 work; wherein the air enters the first compressor (2-3) for compression, increases pressure and temperature, and 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, and after cooling, enters the second compressor (2-4) for compression; the air increases pressure and temperature in the second compressor (2-4), and 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, and after cooling, enters the third compressor (2-7); The second motor (2-8) performs work to drive the third compressor (2-7) to perform work, further compressing the gas. 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) of the third gas-molten salt heat exchange system for heat exchange in sequence. After the compressed air is cooled, it enters the gas storage reservoir (3) for storage; During the heat exchange process of 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, 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 through the molten salt pump (5-15), the low-temperature molten salt is heated into high-temperature molten salt by the compression heat, and returns to the high-temperature molten salt tank (5-12), and part of the compression 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 first gas-molten salt heat exchange system, the second gas-molten salt heat exchange system and the third gas-molten salt heat exchange system through the second water pump (5-16), and returns to the high-temperature water tank (5-14) after being heated, and part of the compression heat is stored in the high-temperature water tank (5-14); The expansion process includes: the compressed air in the gas storage reservoir (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 heated, and enters the first expander (4-1) to perform work. The compressed air after temperature reduction and pressure reduction 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 heated, and enters the second expander (4-2) to perform work. After temperature reduction and pressure reduction, the compressed air is discharged into the atmosphere. The first expander (4-1) and the second expander (4-2) perform work to drive the generator (4-3) to generate electric energy, which is then connected to the power grid.

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