Anti-corrosion gas production system of salt cavern type compressed air energy storage power station and regulation and control method

Abstract

The invention provides a salt cavern type compressed air energy storage power station anti-corrosion gas production system and a regulation and control method, and belongs to the technical field of large-capacity energy storage applied to power system scenes. The system is used for extracting and heating compressed air stored in a salt cavern gas storage and then inputting the compressed air into an expansion machine for expansion and energy release so as to drive a generator to generate electricity, and comprises a separation unit and a heat storage medium heat exchanger; the separation unit is connected to an outlet of the salt cavern gas storage; the heat storage medium heat exchanger is connected between the separation unit and the expansion machine, and the separation unit comprises a coarse separation device for separating solid and liquid impurities in the compressed air and a fine separation device for separating water vapor in the compressed air. According to the invention, corrosive solid-liquid drops and water vapor in compressed air extracted from a salt cavern are separated in a manner of combining coarse separation and fine separation, so that precipitation of water in subsequent equipment is reduced, and clean and dry gas extraction and corrosion protection of the equipment in a power station are realized.

Description

Technical Field

[0001] The present invention relates to an anti-corrosion gas production system and a control method for a salt cavern type compressed air energy storage power station, belonging to the technical field of large-capacity energy storage for power system scenario applications. Background Art

[0002] At present, increasing the amount of renewable energy power generation is an issue that must be faced when building a new power system with renewable energy as the main body. Due to the unstable power generation of renewable energy, some of the generated electricity cannot be connected to the grid, resulting in abandoned electricity. How to reasonably utilize abandoned electricity and balance peak and valley electricity has become a problem that must be solved in the technical path.

[0003] The compressed air energy storage system is an electric energy storage system that can achieve large-capacity and long-term electrical energy storage, including: gas injection compression energy storage stage and gas extraction expansion energy release stage. The gas injection compression energy storage stage refers to compressing air through a compressor during low grid load, converting excess electrical energy into pressure energy and heat energy, and injecting the compressed air into a gas storage reservoir for storage; while the gas extraction expansion energy release stage refers to releasing high-pressure air in the gas storage reservoir during high grid load periods, expanding it through an expander to do work, and driving the generator to generate electricity.

[0004] Compressed air energy storage systems rely on large-capacity, low-leakage, stable and reliable gas storage devices to store compressed high-pressure air. Natural salt caverns are the mainstream gas storage devices for large-scale compressed air energy storage power stations on the current market. They have the advantages of large capacity, strong pressure bearing capacity, high geological stability, strong air tightness, and low development cost. However, during the gas extraction and expansion energy release stage, when the air stored in the salt caverns is released into the compressed air energy storage power station, it will inevitably bring out the salt rock particles and brine in the salt caverns, causing blockage or corrosion of gas pipelines, plant heat exchangers, and expanders, greatly reducing the safety and service life of the compressed air energy storage power station.

[0005] In summary, there is an urgent need to develop an anti-corrosion gas production system for a salt cavern type compressed air energy storage power station with anti-corrosion protection function. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a salt cavern type compressed air energy storage power station anti-corrosion gas production system and a control method, thereby solving the corrosion problem of the existing salt cavern type compressed air energy storage power station anti-corrosion gas production system.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions: In the first aspect, the present invention provides a salt cavern type compressed air energy storage power station anti-corrosion gas production system, comprising: a heat storage medium heat exchanger, an expander, a generator and a separation unit; the separation unit is connected between the salt cavern gas storage reservoir and the heat storage medium heat exchanger, and is used to separate and process the compressed air produced from the salt cavern gas storage reservoir; the heat storage medium heat exchanger uses the heat storage medium to heat the compressed air after separation; the expander uses the heated compressed air to expand and release energy to drive the generator to generate electricity.

[0008] The separation unit comprises: a coarse separation device and a fine separation device connected in series; the coarse separation device is used to separate solid and liquid impurities in compressed air; and the fine separation device is used to separate water vapor in compressed air.

[0009] Furthermore, the fine separation device includes: a first heat exchanger, a second heat exchanger and a subdividing cyclone separator; the first heat exchanger is used to cool the compressed air to condense the water vapor therein; the subdividing cyclone separator is used to separate the precipitated liquid water; the second heat exchanger is used to heat the compressed air; the subdividing cyclone separator is connected between the first heat exchanger and the second heat exchanger.

[0010] Furthermore, the gas outlet of the heat storage medium heat exchanger enters the expander through the expander inlet valve in two ways, one way enters the expander suction chamber, and the other way enters the expander middle stage for gas replenishment through the gas replenishment control valve.

[0011] Furthermore, it includes: a plurality of the heat storage medium heat exchangers, wherein the plurality of the heat storage medium heat exchangers are connected in series or in parallel.

[0012] Furthermore, it also includes: a heat pump temperature control unit; the heat pump temperature control unit includes: a heat pump working fluid compressor, the second heat exchanger, an electronic expansion valve and the first heat exchanger connected in series in sequence; the heat pump working fluid compressor is used to increase the temperature and pressure of the low-temperature and low-pressure gaseous heat pump working fluid; the second heat exchanger condenses and releases heat from the gaseous heat pump working fluid, converts it into a liquid heat pump working fluid, and uses the released heat to heat the compressed air; the electronic expansion valve is used to throttle and reduce the pressure of the liquid heat pump working fluid; the first heat exchanger uses the heat released by the cooling of the compressed air to heat the liquid heat pump working fluid, so that it evaporates into a gaseous heat pump working fluid.

[0013] Furthermore, the heat pump working fluid compressor is driven by the expander; the heat pump working fluid compressor is connected to the expander via a clutch or a gear box.

[0014] Furthermore, there are multiple salt cavern gas storages; the gas outlets of the multiple salt cavern gas storages are merged into one and then connected to the separation unit through a switch valve group.

[0015] In a second aspect, the present invention provides a control method for the anti-corrosion gas production system of the salt cavern type compressed air energy storage power station described in the first aspect, comprising: the separation unit separates and processes the compressed air produced from the salt cavern gas storage reservoir, wherein a coarse separation device in the separation unit first separates solid particles and liquid droplets from the compressed air; a fine separation device in the separation unit then separates water vapor from the compressed air; after the solid particles, liquid droplets and water vapor are separated, the compressed air is heated by the heat storage medium heat exchanger and then enters the expander to expand and release energy, so that the expander drives the generator to generate electricity.

[0016] Furthermore, the fine separation device in the separation unit further separates water vapor from the compressed air, including: cooling the compressed air through a first heat exchanger to precipitate water vapor in the compressed air; separating the cooled compressed air through a fine cyclone separator to separate the water condensed during the cooling process; and heating the compressed air from which the water is separated through a second heat exchanger.

[0017] Furthermore, it also includes: the second heat exchanger condenses the heat pump working fluid to convert it into liquid heat pump working fluid, and recovers the heat released by it to heat the compressed air; the first heat exchanger heats the liquid heat pump working fluid by recovering the heat released by cooling the compressed air, so that it evaporates into gaseous heat pump working fluid.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The salt cavern type compressed air energy storage power station anti-corrosion gas production system provided by the present invention adopts a combination of coarse separation and fine separation to separate corrosive solid and liquid droplets and water vapor in the compressed air produced from the salt cavern, thereby reducing the precipitation of moisture in the subsequent equipment, achieving clean and dry gas production, and anti-corrosion protection of the equipment in the power station; (2) The anti-corrosion gas production system of the salt cavern type compressed air energy storage power station provided by the present invention realizes heat transfer between the first heat exchanger and the second heat exchanger through a heat pump temperature control unit. At the same time, the heat pump compressor is also driven by the expander in the gas production pipeline, thereby realizing efficient utilization of energy in the gas production process of the salt cavern type compressed air energy storage power station. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the anti-corrosion gas production system of the salt cavern type compressed air energy storage power station provided in Example 1 of the present invention; Figure 2 A schematic diagram of an anti-corrosion gas production system for a compressed air energy storage power station including multiple salt cavern gas storages provided in Example 1 of the present invention; Figure 3 A schematic diagram of an anti-corrosion gas production system for a compressed air energy storage power station including a plurality of heat storage medium heat exchangers provided in Example 1 of the present invention; In the figure: 1—salt cavern gas storage; 2—electric regulating valve; 3—stop valve; 4—coarse separation cyclone separator; 5—first heat exchanger; 6—fine separation cyclone separator; 7—second heat exchanger; 8—heat storage medium heat exchanger; 9—expander air inlet valve; 10—air supply control valve; 11—expander; 12—generator; 13—clutch; 14—heat pump working fluid compressor; 15—electronic expansion valve. DETAILED DESCRIPTION

[0020] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Example 1

[0021] like Figure 1 As shown, the present invention provides a salt cavern type compressed air energy storage power station anti-corrosion gas production system, which is used to extract and heat the compressed air stored in the salt cavern gas storage reservoir 1, and then input it into the expander 11 to expand and release energy, so as to drive the generator 12 to generate electricity.

[0022] It should be noted that when the salt cavern gas storage 1 releases compressed air, it will inevitably bring out salt rock particles and brine in the salt cavern, and the compressed air also contains water vapor.

[0023] The above system comprises: a heat storage medium heat exchanger 8, an expander 11, a generator 12 and a separation unit.

[0024] Specifically, the separation unit is connected between the salt cavern gas storage reservoir 1 and the heat storage medium heat exchanger 8, and is used to separate and process the compressed air extracted from the salt cavern gas storage reservoir 1; the heat storage medium heat exchanger 8 uses the heat storage medium to heat the compressed air after separation; the expander 11 uses the heated compressed air to expand and release energy to drive the generator 12 to generate electricity.

[0025] The separation unit comprises two parts: a rough separation device for separating solid and liquid impurities in compressed air and a fine separation device for separating water vapor in compressed air; the rough separation device is connected in series before the fine separation device.

[0026] In this embodiment, the rough separation device adopts a rough separation cyclone separator 4.

[0027] like Figure 2As shown, in some specific embodiments, there are multiple salt cavern gas storages 1. The gas outlets of the multiple salt cavern gas storages 1 are merged into one and then connected to the separation unit through a switch valve group.

[0028] In a more specific embodiment, the switch valve group includes: an electric regulating valve 2 and a stop valve 3 .

[0029] During the expansion and energy release stage of the compressed air energy storage power station, the compressed air in the underground salt cavern gas storage reservoir 1 reaches the ground through the injection and production pipeline, and enters the coarse cyclone separator 4 through the electric regulating valve 2 and the stop valve 3. The coarse cyclone separator 4 separates the solid particles and droplet impurities in the compressed air.

[0030] In some specific embodiments, the fine separation device includes: a first heat exchanger 5, a second heat exchanger 7 and a subdividing cyclone separator 6. The first heat exchanger 5 is used to cool the compressed air to condense the water vapor therein; the subdividing cyclone separator 6 is used to separate the precipitated liquid water; the second heat exchanger 7 is used to heat the compressed air; and the subdividing cyclone separator 6 is connected between the first heat exchanger 5 and the second heat exchanger 7.

[0031] The compressed air after separation processing enters the heat storage medium heat exchanger 8 to continue heating.

[0032] like Figure 3 As shown, in some specific embodiments, multiple heat storage medium heat exchangers 8 are included, and the multiple heat storage medium heat exchangers 8 are connected in series or in parallel. The gas outlet of the heat storage medium heat exchanger 8 enters the expander 11 through the expander inlet valve 9 in two ways, one way enters the expander suction chamber, and the other way enters the expander intermediate stage through the gas replenishment control valve 10 for gas replenishment.

[0033] The heat storage medium of the heat storage medium heat exchanger 8 can be fluids such as water, heat transfer oil, and molten salt.

[0034] The salt cavern type compressed air energy storage power station anti-corrosion gas production system provided in this embodiment realizes two separation operations of coarse separation and fine separation of the compressed air extracted from the salt cavern gas storage reservoir 1 by adding a separation unit, and respectively separates corrosive solid particles and droplets in the compressed air, and water vapor in the compressed air, thereby ensuring the cleanliness and dryness of the compressed air entering the heat storage medium heat exchanger 8, reducing the precipitation of water in subsequent equipment such as the heat storage medium heat exchanger 8, thereby realizing anti-corrosion protection of the equipment in the power station. Example 2

[0035] This embodiment provides a heat pump temperature control unit that utilizes a reverse Carnot cycle to first reduce and then increase the temperature of compressed air in a gas collection pipeline, and is used to cooperate with a first heat exchanger 5 and a second heat exchanger 7 to realize heat recycling.

[0036] The heat pump temperature control unit is formed by connecting the heat pump working fluid compressor 14, the second heat exchanger 7, the electronic expansion valve 15 and the first heat exchanger 5 in series. The heat pump working fluid compressor 14 heats up and pressurizes the low-temperature and low-pressure gaseous heat pump working fluid. Then, the high-temperature and high-pressure gaseous heat pump working fluid enters the second heat exchanger 7. The second heat exchanger 7 condenses and releases heat on the gaseous heat pump working fluid to convert it into a liquid heat pump working fluid. Then, the liquid heat pump working fluid enters the first heat exchanger 5 after throttling and reducing the pressure through the electronic expansion valve 15. The first heat exchanger 5 uses the heat released by the cooling of the compressed air to heat the liquid heat pump working fluid, evaporate it into a gaseous heat pump working fluid, and return to the inlet of the heat pump compressor 14.

[0037] The working fluid of the heat pump can be natural or artificial synthetic working fluids such as CO2 and 1,1,1,2-tetrafluoroethane.

[0038] In some specific embodiments, the expander 11 is connected to the generator 12 via a shaft to generate electricity, and drives the heat pump compressor 14 via a clutch 13 or a gear box.

[0039] The heat pump temperature control unit in this embodiment realizes the recycling of heat between the first heat exchanger 5 and the second heat exchanger 7 in the gas production pipeline of the pressure storage power station by coupling the heat pump, thereby improving the utilization rate of thermal energy and reducing energy waste. Example 3

[0040] This embodiment provides a control method for the anti-corrosion gas production system of the salt cavern type compressed air energy storage power station described in Embodiment 1 or Embodiment 2.

[0041] Step 1: The separation unit separates and processes the compressed air produced by the salt cavern gas storage 1.

[0042] Specifically, the coarse separation device in the separation unit first separates solid particles and liquid droplets from the compressed air; and the fine separation device in the separation unit then separates water vapor from the compressed air.

[0043] In some specific embodiments, the steps performed by the fine separation device in the separation unit include: first cooling the compressed air through the first heat exchanger 5 to precipitate water vapor in the compressed air; then, separating the cooled compressed air through the fine cyclone separator 6 to separate the water condensed during the cooling process; finally, heating the compressed air from which the water is separated through the second heat exchanger 7.

[0044] After the solid particles, liquid droplets and water vapor are separated, the compressed air is heated by the heat storage medium heat exchanger 8 and then enters the expander 11 to expand and release energy, so that the expander 11 drives the generator 12 to generate electricity.

[0045] In an embodiment containing a heat pump temperature control unit, the method also includes: the second heat exchanger 7 condenses the heat pump working fluid to convert it into liquid heat pump working fluid, and recovers the heat released to heat the compressed air; the first heat exchanger 5 heats the liquid heat pump working fluid by recovering the heat released by cooling the compressed air, so that it evaporates into gaseous heat pump working fluid.

[0046] In this embodiment, the first heat exchanger 5 and the second heat exchanger 7 cooperate with the heat pump temperature control unit to achieve efficient transfer and utilization of heat between compressed air and heat pump working fluid, thereby reducing system energy consumption.

[0047] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A salt cavern type compressed air energy storage power station anti-corrosion gas production system, characterized in that: include: Heat storage medium heat exchanger, expander, generator and separation unit; The separation unit is connected between the salt cavern gas storage and the heat storage medium heat exchanger, and is used to separate and process the compressed air extracted from the salt cavern gas storage; The heat storage medium heat exchanger heats the separated compressed air using the heat storage medium; The expander utilizes the heated compressed air to expand and release energy to drive the generator to generate electricity; The separation unit comprises: a coarse separation device and a fine separation device connected in series; The rough separation device is used to separate solid and liquid impurities in compressed air; The fine separation device is used to separate water vapor from compressed air.

2. The anti-corrosion gas production system of the salt cavern type compressed air energy storage power station according to claim 1 is characterized in that: The fine separation device comprises: a first heat exchanger, a second heat exchanger and a subdividing cyclone separator; The first heat exchanger is used to cool the compressed air to condense the water vapor therein; The subdividing cyclone separator is used to separate the precipitated liquid water; The second heat exchanger is used to heat the compressed air; The subdividing cyclone separator is connected between the first heat exchanger and the second heat exchanger.

3. The anti-corrosion gas production system of the salt cavern type compressed air energy storage power station according to claim 1 is characterized in that: The gas outlet of the heat storage medium heat exchanger enters the expander through the expander inlet valve in two ways, one way enters the expander suction chamber, and the other way enters the expander middle stage through the air replenishment control valve for air replenishment.

4. The anti-corrosion gas production system of the salt cavern type compressed air energy storage power station according to claim 3 is characterized in that: include: The plurality of heat storage medium heat exchangers are connected in series or in parallel.

5. The anti-corrosion gas production system of the salt cavern type compressed air energy storage power station according to claim 2 is characterized in that: Also includes: Heat pump temperature control unit; The heat pump temperature control unit comprises: a heat pump working medium compressor, the second heat exchanger, an electronic expansion valve and the first heat exchanger connected in series in sequence; The heat pump working fluid compressor is used to increase the temperature and pressure of the low-temperature and low-pressure gaseous heat pump working fluid; The second heat exchanger condenses and releases heat from the gaseous heat pump working fluid to convert it into a liquid heat pump working fluid, and uses the released heat to heat the compressed air; The electronic expansion valve is used to throttle and reduce the pressure of the liquid heat pump working medium; The first heat exchanger utilizes the heat released by the cooling of the compressed air to heat the liquid heat pump working fluid, causing it to evaporate into a gaseous heat pump working fluid.

6. The anti-corrosion gas production system of the salt cavern type compressed air energy storage power station according to claim 5 is characterized in that: The heat pump working fluid compressor is driven by the expander; the heat pump working fluid compressor is connected to the expander via a clutch or a gear box.

7. The anti-corrosion gas production system of the salt cavern type compressed air energy storage power station according to claim 1 is characterized in that: There are multiple salt cavern gas storages; the gas outlets of the multiple salt cavern gas storages are merged into one and then connected to the separation unit through a switch valve group.

8. A control method for the anti-corrosion gas production system of a salt cavern type compressed air energy storage power station according to any one of claims 1 to 7, characterized in that: include: The separation unit separates and processes the compressed air extracted from the salt cavern gas storage, wherein the coarse separation device in the separation unit first separates solid particles and liquid droplets from the compressed air; the fine separation device in the separation unit then separates water vapor from the compressed air; After the solid particles, liquid droplets and water vapor are separated, the compressed air is heated by the heat storage medium heat exchanger and then enters the expander to expand and release energy, so that the expander drives the generator to generate electricity.

9. The control method of the anti-corrosion gas production system of the salt cavern type compressed air energy storage power station according to claim 8 is characterized in that: The fine separation device in the separation unit further separates water vapor from the compressed air, including: The compressed air is cooled by a first heat exchanger to separate water vapor from the compressed air; The cooled compressed air is separated by a subdivided cyclone separator to separate the water condensed during the cooling process; The compressed air from which moisture has been separated is heated by the second heat exchanger.

10. The control method of the anti-corrosion gas production system of the salt cavern type compressed air energy storage power station according to claim 9, characterized in that: Also includes: The second heat exchanger condenses the heat pump working fluid to convert it into liquid heat pump working fluid, and recovers the heat released by the heat pump working fluid to heat the compressed air; The first heat exchanger heats the liquid heat pump working fluid by recovering the heat released by cooling the compressed air, so that the liquid heat pump working fluid evaporates into the gaseous heat pump working fluid.

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