CN111305919A - A flexible peak-shaving system and method for air energy storage in a power plant - Google Patents

Abstract

The invention discloses a flexible peak regulation system and method for air energy storage in a power plant. The system includes a liquid compressed air energy storage system and a coal-fired unit power generation system. The operation modes of the system include an energy storage mode and an energy release mode. When the electricity load is low and there is surplus electricity, the energy storage mode is turned on, and the surplus electricity is used to drive the multi-stage compressor to compress the air. The energy release mode is turned on when the grid electricity consumption peaks and there is a lack of electricity supply. The expander generates electricity and outputs electric energy to the outside; the invention can improve the efficiency of the energy storage system, and at the same time avoid the problems of high energy consumption and low service life when using a high pressure ratio compressor; the invention cancels the traditional liquid compressed air energy storage system. The thermal system reduces the investment of the energy storage system, and at the same time solves the problem of heat mismatch between the energy storage process and the energy release process.

Description

A flexible peak-shaving system and method for air energy storage in a power plant

technical field

The invention belongs to the technical field of energy storage peak regulation, and in particular relates to a flexible peak regulation system and method for air energy storage in a power plant, which is suitable for various thermal power plants typified by coal-fired units, and can improve the flexibility of the coal-fired units , peak shaving capacity and economic benefits, and at the same time can improve the energy storage efficiency of the liquid compressed air energy storage system.

Background technique

Renewable energy such as wind energy and solar energy in my country is developing rapidly year by year. By the end of 2018, my country's photovoltaic and wind power installed capacity reached 172 million kilowatts and 184 million kilowatts respectively, and the total annual power generation reached 543.5 billion kilowatt hours. , the shortcomings of strong randomness, in order to fully absorb new energy, the power grid has greatly increased the requirements for the number and depth of peak shaving of coal-fired units. In addition, the electricity consumption of the whole society is increasing year by year, and the peak-to-valley difference of electricity consumption in the power grid is increasing day by day, which also increases the peak regulation pressure of coal-fired units.

The construction of large-scale energy storage facilities can effectively improve the peak shaving capacity of the power grid and the consumption level of renewable energy. At present, pumped storage is the most mature large-scale energy storage technology. It has high efficiency but strict site selection conditions and a long construction period. Electrochemical battery energy storage technology has fast response, small size, but short life and average cost. It is very high and the safety risk is high. Whether it is suitable for the construction of large-scale energy storage still needs engineering demonstration and verification; the liquid compressed air energy storage technology has a long service life, low average cost, and does not depend on the geographical environment. It is a large-scale energy storage technology with great development potential. energy technology.

In the liquid compressed air energy storage system, a large amount of compression heat will be generated in the process of compressing the air. In order to improve the energy storage efficiency of the energy storage system, a heat storage system will be constructed to recover the compression heat and improve the temperature grade of the compression heat as much as possible. In the compressed air energy storage technology, the pressure of the outlet air of the final stage compressor is about 10MPa, and the temperature is basically between 200°C and 400°C. At present, there is still a trend of further improvement, but increasing the working temperature of the compressor will lead to deterioration of compressor performance and power consumption. The volume increases and the service life decreases, and there is also a lack of compressors that can withstand this level of temperature and pressure on the market. In addition, for the conventional liquid compressed air energy storage system, the heat obtained by the heat storage system during the energy storage process is greater than the heat required in the energy release process, which will cause energy waste.

SUMMARY OF THE INVENTION

In order to overcome the shortcomings of the existing large-scale energy storage peak regulation technology, the present invention proposes a power plant air energy storage flexible peak regulation system and method. The air compressor in the system can work under the working conditions of medium and low temperature and small pressure ratio. , reducing the energy loss of the compressor, improving the energy storage efficiency, and significantly enhancing the flexibility and peak shaving capacity of the coal-fired unit.

In order to achieve the above objects, the present invention adopts the following technical solutions.

A flexible peak regulation system for air energy storage in a power plant, comprising: a compressor 1, a cooler 2, a gas-liquid conversion device 3, a liquid air storage tank 4, a heater 5, an expander 6, a new compressor 21 and A liquid compressed air energy storage system consisting of a new cooler 22; consists of a condenser 11, a condensate pump 12, a primary low pressure heater 13-1, a secondary low pressure heater 13-2, a deaerator 14, and a feed water pump 15 , a high-pressure heater 16, a boiler 17, a high-pressure cylinder 18, a medium-pressure cylinder 19 and a low-pressure cylinder 20. The coal-fired power generation system consists of a first valve 7, a second valve 8, a third valve 9 and a fourth valve 10. the control valve group;

The outlet of the compressor 1 is sequentially connected to the high temperature side inlet of the cooler 2, the high temperature side outlet of the cooler 2, the newly added compressor 21, the newly added cooler 22 high temperature side inlet, the newly added cooler 22 high temperature side outlet, and the gas-liquid conversion device. 3 cooling and liquefaction side inlet, gas-liquid conversion device 3 cooling and liquefaction side outlet and liquid air storage tank 4 inlet; the liquid air storage tank 4 outlet is connected to the gas-liquid conversion device 3 cold energy recovery side inlet, gas-liquid conversion device 3 cold energy recovery in turn The side outlet, the low temperature side inlet of the heater 5, the low temperature side outlet of the heater 5 and the expander 6; the outlet of the condenser 11 is connected to the condensate water pump 12, the primary low pressure heater 13-1, the secondary low pressure heater 13-2, Deaerator 14, feed pump 15, high pressure heater 16, boiler 17 condensate inlet, boiler 17 main steam outlet, high pressure cylinder 18, boiler 17 reheat steam inlet, boiler 17 reheat steam outlet, medium pressure cylinder 19, low pressure The inlet of the cylinder 20 and the condenser 11; the first valve 7 is connected to the outlet of the condensate pump 12 on one side, the other side of the first valve 7 is connected to the low temperature side inlet of the cooler 2 and the low temperature side inlet of the newly added cooler 22, and the second valve One side of 8 is communicated with the outlet of the first-stage low pressure heater 13-1, the other side of the second valve 8 is communicated with the outlet of the low temperature side of the cooler 2 and the outlet of the low temperature side of the newly added cooler 22, and one side of the third valve 9 is communicated with the low pressure cylinder 20 The inlet is communicated, the other side of the third valve 9 is communicated with the high temperature side inlet of the heater 5, the fourth valve 10 side is communicated with the outlet of the condenser 11, and the other side of the fourth valve 10 is communicated with the high temperature side outlet of the heater 5; the The system cancels the heat storage system in the liquid compressed air energy storage system, and uses the extraction steam of the coal-fired unit power generation system to heat the low-temperature air, so that the compressor 1 and the newly added compressor 21 can be used in medium and low temperature, single-stage small pressure ratio conditions. It can work under low temperature, and can effectively utilize the latent heat of steam, which improves the energy storage efficiency of the liquid compressed air energy storage system.

The low-pressure cylinder 20 can work under the minimum safe steam flow (the effective output work of the low-pressure cylinder is about zero), and at this time, the energy storage efficiency of the entire system is the highest.

The compressor 1 and the cooler 2 are of one or more stages, the number of the compressor 1 and the cooler 2 is in one-to-one correspondence, and each stage of the compressor is connected to a corresponding cooler in series.

The newly added compressor 21 and the newly added cooler 22 are both one-stage or multi-stage, and are connected in series with the compressor 1 and the cooler 2. The number of the newly added compressor 21 and the newly added cooler 22 corresponds to each The corresponding new coolers are connected in series after adding compressors.

The newly added compressor 21 represents the newly added compression stage after the optimized design, and the function is to reduce the pressure ratio of the air in the compression process of each stage, thereby reducing the compressor outlet air temperature of the compressor 1 and the newly added compressor 21 and reducing the compression molding machine. 1 and the power consumption of the newly added compressor 21.

The heaters 5 and the expanders 6 are both of one or more stages, and the numbers of the heaters 5 and the expanders 6 correspond one-to-one, and each stage of the heaters is connected to a corresponding expander in series.

The third valve 9 is communicated with the outlet of the medium-pressure cylinder 19 and the inlet of the low-pressure cylinder 20, and the extraction position can also be optimized and screened according to the specific conditions of the generator set.

The system is suitable for cogeneration units and pure condensing units, which can improve the flexibility, peak shaving capacity and economic benefits of the units, and at the same time improve the energy storage efficiency of the liquid compressed air energy storage system.

The functions of the first valve 7 , the second valve 8 , the third valve 9 and the fourth valve 10 are to control the system to work in the energy storage mode or the energy release mode.

The operation method of the air energy storage flexible peak regulation system in a power plant includes an energy storage mode and an energy release mode, and the details are as follows:

Energy storage mode: The energy storage mode is turned on when the power consumption of the grid is low and there is excess power, the first valve 7 and the second valve 8 are opened, and the third valve 9 and the fourth valve 10 are closed; On the air side, the normal temperature and normal pressure air enters the compressor 1. Increase the pressure and temperature, enter the cooler 2 to reduce the temperature, then enter the newly added compressor 21 to increase the pressure and temperature, and then enter the newly-added cooler 22 to reduce the temperature. The normal temperature and high pressure air is cooled and liquefied through the gas-liquid conversion device 3, and the low temperature liquid The air enters the liquid air storage tank 4 for storage; on the water side, after the condensed water at the outlet of the condenser 11 is pressurized by the condensate pump 12, part or all of the condensed water enters the cooler 2 and the newly added cooler 22 through the first valve 7 to cool the high temperature The air returns to the inlet of the secondary low pressure heater 13-2 through the second valve 8, and the rest of the condensed water directly enters the primary low pressure heater 13-1, and the outlet water of the secondary low pressure heater 13-2 passes through the deaerator 14 in turn. , the feed water pump 15, the high pressure heater 16 and the boiler 17 generate main steam, the main steam enters the high pressure cylinder 18 to expand and perform work to generate cold reheat steam, and then the boiler 17 raises the temperature to generate hot reheat steam, and then enters the medium pressure in turn Cylinder 19, low-pressure cylinder 20 and condenser 11, in which steam condenses into condensed water;

Energy release mode: open the energy release mode when the grid electricity peaks and lack of power supply, close the first valve 7 and the second valve 8, open the third valve 9 and the fourth valve 10; on the air side, the low-temperature liquid air is stored from the liquid air. The tank 4 flows out, and after the cold energy is recovered by the gas-liquid conversion device 3, normal temperature and high pressure air is generated, and then enters the heater 5 to increase the temperature, and then enters the expander 6 to expand and output electric energy. The outlet of the expander 6 is normal pressure and normal temperature air, and the discharge On the water side, part or all of the steam at the outlet of the medium-pressure cylinder 19 enters the heater 5 through the third valve 9 to heat the air, and then enters the condensate pump 12 through the fourth valve 10, and the rest of the steam directly enters the low-pressure cylinder 20 to continue working. All the condensed water at the outlet of the condensate pump 12 enters the first-stage low-pressure heater 13-1, and the circulation process of water in other equipment is the same as that in the energy storage mode.

Compared with the prior art, the present invention has the following advantages:

The air energy storage flexible peak regulation system and method of the power plant of the invention are used to solve the increasingly prominent large-capacity peak regulation problem in the power grid, and can significantly improve the flexibility of the coal-fired unit, thereby improving the grid's ability to absorb renewable energy power generation ; The operating modes of the system include energy storage mode and energy release mode. When the electricity load of the grid is low and there is surplus electricity, the energy storage mode is turned on, and the surplus electricity is used to drive the multi-stage compressor to compress the air. Turn on the energy release mode, use the extraction steam of the coal-fired unit to heat the low-temperature air, and push the expander to generate electricity to output electric energy to the outside world; the invention can improve the efficiency of the energy storage system, and at the same time avoid the high energy consumption and low life expectancy when using a high-pressure compressor. Problem: The present invention cancels the heat storage system in the traditional liquid compressed air energy storage system, reduces the investment of the energy storage system, and solves the problem of heat mismatch between the energy storage process and the energy release process.

Description of drawings

FIG. 1 is a schematic diagram of the system of the present invention.

Figure 2 is a schematic diagram of a conventional liquid compressed air energy storage system.

In the picture:

1-Compressor 2-Cooler 3-Gas-liquid conversion device 4-Liquid air storage tank

5-Heater 6-Expander 7-First valve 8-Second valve 9-Third valve

10-The fourth valve 11-Condenser 12-Condensate pump 13-1-First-stage low pressure heater

13-2-Secondary low pressure heater 14-Deaerator 15-Feed water pump 16-High pressure heater

17-Boiler 18-High Pressure Cylinder 19-Medium Pressure Cylinder 20-Low Pressure Cylinder 21-Added Compressor

22-Add cooler

Detailed ways

The patent of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The specific embodiments described herein are only used to explain the present invention, and are not intended to limit the present invention.

As shown in Figure 1, a flexible peak regulation system for air energy storage in a power plant of the present invention includes: a compressor 1, a cooler 2, a gas-liquid conversion device 3, a liquid air storage tank 4, a heater 5, an expander 6. A liquid compressed air energy storage system consisting of a new compressor 21 and a new cooler 22; consisting of a condenser 11, a condensate pump 12, a first-stage low-pressure heater 13-1, a second-stage low-pressure heater 13-2, A coal-fired power generation system composed of a deaerator 14, a feed pump 15, a high-pressure heater 16, a boiler 17, a high-pressure cylinder 18, a medium-pressure cylinder 19 and a low-pressure cylinder 20; the first valve 7, the second valve 8, the third A control valve group consisting of valve 9 and fourth valve 10;

The outlet of the compressor 1 is sequentially connected to the high temperature side inlet of the cooler 2, the high temperature side outlet of the cooler 2, the newly added compressor 21, the newly added cooler 22 high temperature side inlet, the newly added cooler 22 high temperature side outlet, and the gas-liquid conversion device. 3. The inlet of the cooling and liquefaction side, the outlet of the gas-liquid conversion device 3, the outlet of the cooling and liquefied side, and the inlet of the liquid air storage tank 4; at the same time, the outlet of the liquid air storage tank 4 is sequentially connected to the inlet of the gas-liquid conversion device 3 cold energy recovery side, and the gas-liquid conversion device 3. The outlet on the recovery side, the inlet on the low temperature side of the heater 5, the outlet on the low temperature side of the heater 5 and the expander 6; 2. Deaerator 14, feed pump 15, high pressure heater 16, condensate inlet of boiler 17, main steam outlet of boiler 17, high pressure cylinder 18, reheat steam inlet of boiler 17, reheat steam outlet of boiler 17, medium pressure cylinder 19 , low pressure cylinder 20 and the inlet of condenser 11; one side of the first valve 7 is communicated with the outlet of the condensate pump 12, the other side of the first valve 7 is communicated with the low temperature side inlet of the cooler 2 and the low temperature side inlet of the newly added cooler 22, the first One side of the second valve 8 is connected to the outlet of the primary low pressure heater 13-1, the other side of the second valve 8 is connected to the low temperature side outlet of the cooler 2 and the low temperature side outlet of the newly added cooler 22, and one side of the third valve 9 is connected to the low pressure side The inlet of the cylinder 20 is in communication, the other side of the third valve 9 is in communication with the inlet of the high temperature side of the heater 5, one side of the fourth valve 10 is in communication with the outlet of the condenser 11, and the other side of the fourth valve 10 is in communication with the outlet of the high temperature side of the heater 5 . The system of the invention is suitable for cogeneration units and pure condensing units, and can improve the flexibility, peak regulation capability and economic benefits of the units, and at the same time improve the energy storage efficiency of the liquid compressed air energy storage system.

The flexible peak regulation system for air energy storage in a power plant of the present invention can operate according to the following energy storage mode and energy release mode.

Energy storage mode: The energy storage mode is turned on when the power consumption of the grid is low and there is excess power, the first valve 7 and the second valve 8 are opened, and the third valve 9 and the fourth valve 10 are closed; On the air side, the normal temperature and normal pressure air enters the compressor 1. Increase the pressure and temperature, enter the cooler 2 to reduce the temperature, then enter the newly added compressor 21 to increase the pressure and temperature, and then enter the newly-added cooler 22 to reduce the temperature. The normal temperature and high pressure air is cooled and liquefied through the gas-liquid conversion device 3, and the low temperature liquid The air enters the liquid air storage tank 4 for storage; on the water side, after the condensed water at the outlet of the condenser 11 is pressurized by the condensate pump 12, part or all of the condensed water enters the cooler 2 and the newly added cooler 22 through the first valve 7 to cool the high temperature The air returns to the inlet of the secondary low pressure heater 13-2 through the second valve 8, and the rest of the condensed water directly enters the primary low pressure heater 13-1, and the outlet water of the secondary low pressure heater 13-2 passes through the deaerator 14 in turn. , the feed water pump 15, the high pressure heater 16 and the boiler 17 generate main steam, the main steam enters the high pressure cylinder 18 to expand and perform work to generate cold reheat steam, and then the boiler 17 raises the temperature to generate hot reheat steam, and then enters the medium pressure in turn Cylinder 19, low-pressure cylinder 20 and condenser 11, in which steam condenses into condensed water.

Energy release mode: open the energy release mode when the grid electricity peaks and lack of power supply, close the first valve 7 and the second valve 8, open the third valve 9 and the fourth valve 10; on the air side, the low-temperature liquid air is stored from the liquid air. The tank 4 flows out, and after the cold energy is recovered by the gas-liquid conversion device 3, normal temperature and high pressure air is generated, and then enters the heater 5 to increase the temperature, and then enters the expander 6 to expand and output electric energy. The outlet of the expander 6 is normal pressure and normal temperature air, and the discharge On the water side, part or all of the steam at the outlet of the medium-pressure cylinder 19 enters the heater 5 through the third valve 9 to heat the air, and then enters the condensate pump 12 through the fourth valve 10, and the rest of the steam directly enters the low-pressure cylinder 20 to continue working. All the condensed water at the outlet of the condensate pump 12 enters the first-stage low-pressure heater 13-1, and the circulation process of water in other equipment is the same as that in the energy storage mode.

In this embodiment, the compressor 1 and the cooler 2 represent a three-stage "compression-cooling" process, and the heater 5 and the expander 6 represent a three-stage "heating-expansion" process; When the ratio is 5.2, the outlet air temperature is about 240°C. Increasing the pressure ratio can continue to increase the compressor outlet air temperature. The low-temperature heat transfer oil enters the cooler 2 from the cold tank of the heat storage system to re-cool the air to 30°C. It is stored in the heat tank of the heat storage system; during the energy release process, the high-temperature heat-conducting oil enters the heater 5 from the heat storage system heat tank to reheat the air to 206°C, and the air temperature at the outlet of the expander is about 60°C, completing a complete energy storage. Process and energy release process, the energy storage efficiency of the system is about 57%; using the system and method proposed by the present invention, the newly added compression stage 21 and the newly added cooler 22 represent a four-stage "compression-cooling" process, each stage of compressor pressure The ratio is reduced to 1.9, the air temperature at the compressor outlet is about 100°C, and the energy storage efficiency is increased to about 72% under the condition that the working parameters are unchanged during the energy release process, and the heat storage of the heat transfer oil in the liquid compressed air energy storage system is reduced. system construction.

FIG. 2 is a schematic diagram of a conventional liquid compressed air energy storage system. During the energy storage process, the compressor 1 is used to compress the air at normal temperature and pressure. The air is cooled by the cooler 2 and then enters the gas-liquid conversion device 3 for cooling and liquefaction, and then stored in the liquid air storage tank 4. The heat released by the air in the cooler 2 It is stored in the heat storage system; during the energy release process, the low-temperature liquid air flows out from the liquid air storage tank 4 and enters the gas-liquid conversion device 3 for cold energy recovery, then enters the heater 5 to increase the temperature, and then enters the expander 6 for expansion. Work, the heat absorbed by the air in the heater 5 comes from the heat storage system. In order to improve the energy storage efficiency of conventional liquid compressed air energy storage systems, it is necessary to increase the outlet temperature of the compressor as much as possible, which results in poor compressor operating conditions and difficulty in manufacturing. In addition, a large-capacity heat storage system must be built, which increases investment costs.

Although the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative rather than restrictive. Under the inspiration of the present invention, many modifications can be made without departing from the spirit of the present invention, which all belong to the protection of the present invention. Any insubstantial modification of the present invention by using this concept shall be regarded as an act infringing the protection scope of the present invention.

Claims (10)

1. A flexible peak regulation system for air energy storage in a power plant, characterized in that it comprises: a compressor (1), a cooler (2), a gas-liquid conversion device (3), a liquid air storage tank (4), A liquid compressed air energy storage system composed of a heater (5), an expander (6), a newly added compressor (21) and a newly added cooler (22); Primary low pressure heater (13-1), secondary low pressure heater (13-2), deaerator (14), feed water pump (15), high pressure heater (16), boiler (17), high pressure cylinder ( 18), a coal-fired power generation system composed of a medium-pressure cylinder (19) and a low-pressure cylinder (20); a first valve (7), a second valve (8), a third valve (9) and a fourth valve (10) ) composed of the control valve group; The outlet of the compressor (1) is sequentially connected to the high temperature side inlet of the cooler (2), the high temperature side outlet of the cooler (2), the newly added compressor (21), the newly added cooler (22) high temperature side inlet, and the newly added cooling (22) high temperature side outlet, gas-liquid conversion device (3) cooling and liquefaction side inlet, gas-liquid conversion device (3) cooling and liquefaction side outlet, and liquid air storage tank (4) inlet; the liquid air storage tank (4) outlet is in sequence Connecting the gas-liquid conversion device (3) the cold energy recovery side inlet, the gas-liquid conversion device (3) cold energy recovery side outlet, the heater (5) low temperature side inlet, the heater (5) low temperature side outlet and the expander (6) ; The outlet of the condenser (11) is sequentially connected to the condensate pump (12), the first-stage low-pressure heater (13-1), the second-stage low-pressure heater (13-2), the deaerator (14), and the feed water pump (15) , high pressure heater (16), boiler (17) condensate inlet, boiler (17) main steam outlet, high pressure cylinder (18), boiler (17) reheat steam inlet, boiler (17) reheat steam outlet, medium pressure Cylinder (19), low pressure cylinder (20) and inlet of condenser (11); one side of first valve (7) is communicated with the outlet of condensate pump (12), and the other side of first valve (7) is connected with cooler (2) ) The low temperature side inlet is connected with the low temperature side inlet of the newly added cooler (22); one side of the second valve (8) is connected with the outlet of the primary low pressure heater (13-1), and the other side of the second valve (8) is connected with the cooling The low temperature side outlet of the cooler (2) is connected to the low temperature side outlet of the newly added cooler (22); one side of the third valve (9) is connected to the inlet of the low pressure cylinder (20), and the other side of the third valve (9) is connected to the heater ( 5) The high temperature side inlet is connected; one side of the fourth valve (10) is connected to the outlet of the condenser (11), and the other side of the fourth valve (10) is connected to the high temperature side outlet of the heater (5). The heat storage system in the compressed air energy storage system uses the extraction steam from the power generation system of the coal-fired unit to heat the low-temperature air, so that the compressor (1) and the newly added compressor (21) can be operated in medium and low temperature, single-stage small pressure ratio conditions It can work under low temperature, and can effectively utilize the latent heat of steam, which improves the energy storage efficiency of the liquid compressed air energy storage system. 2. The flexible peak regulation system for air energy storage in a power plant according to claim 1, characterized in that: the low pressure cylinder (20) can work under the minimum safe steam flow, and the energy storage efficiency of the entire system at this time Highest. 3. A power plant air energy storage flexible peak regulation system according to claim 1, characterized in that: the compressor (1) and the cooler (2) are both one-stage or multi-stage, and the compressor ( 1) One-to-one correspondence with the number of coolers (2), and the corresponding coolers are connected in series after each stage of compressor. 4 . The flexible peak regulation system for air energy storage in a power plant according to claim 1 , wherein the newly added compressor ( 21 ) and the newly added cooler ( 22 ) are both one-stage or multi-stage , and the compressor (1) and the cooler (2) are in series relationship, the number of new compressors (21) and new coolers (22) correspond one by one, and the number of new compressors added in series after each stage is added. device. 5 . The flexible peak regulation system for air energy storage in a power plant according to claim 1 , wherein the newly added compressor ( 21 ) can reduce the pressure ratio of air in each stage of compression, thereby reducing the compression ratio. 6 . The outlet air temperature of the machine (1) and the newly added compressor (21) is reduced, and the power consumption of the compression molding machine (1) and the newly added compressor (21) is reduced. 6. A power plant air energy storage flexible peak regulation system according to claim 1, characterized in that: the heater (5) and the expander (6) are both one-stage or multistage, and the heater ( 5) One-to-one correspondence with the number of expanders (6), and the corresponding expanders are connected in series after each stage of heater. 7 . The flexible peak regulation system for air energy storage in a power plant according to claim 1 , wherein the third valve ( 9 ) communicates with the outlet of the medium pressure cylinder ( 19 ) and the inlet of the low pressure cylinder ( 20 ). 8 . , or optimize and filter the extraction position according to the specific conditions of the generator set. 8. A power plant air energy storage flexible peak regulation system according to claim 1, characterized in that: the system is suitable for cogeneration units and pure condensing units, and can improve the flexibility, peak regulation capability and Economic benefits while improving the energy storage efficiency of liquid compressed air energy storage systems. 9. A power plant air energy storage flexible peak regulation system according to claim 1, characterized in that: the first valve (7), the second valve (8), the third valve (9) and the first valve (7), the second valve (8), the third valve (9) and the The function of the four valves (10) is to control the system to work in the energy storage mode or the energy release mode. 10. The operation method of an air energy storage flexible peak shaving system in a power plant according to any one of claims 1 to 9, characterized in that: comprising an energy storage mode and an energy release mode, the details are as follows: Energy storage mode: open the energy storage mode when the power consumption of the grid is low and there is excess power, open the first valve (7) and the second valve (8), close the third valve (9) and the fourth valve (10); the air side , the normal temperature and normal pressure air enters the compressor (1) to increase the pressure and temperature, enters the cooler (2) to reduce the temperature, then enters the newly added compressor (21) to increase the pressure and temperature, and then enters the newly added cooler (22) to reduce the temperature , the normal temperature and high pressure air is cooled and liquefied through the gas-liquid conversion device (3), and the low-temperature liquid air enters the liquid air storage tank (4) for storage; on the water side, the condensed water at the outlet of the condenser (11) is pressurized by the condensate pump (12). , part or all of the condensed water enters the cooler (2) and the new cooler (22) respectively through the first valve (7) to cool the high-temperature air, and then returns to the secondary low-pressure heater (13- 2) At the inlet, the rest of the condensed water directly enters the primary low pressure heater (13-1), and the outlet water of the secondary low pressure heater (13-2) passes through the deaerator (14), the feed pump (15), and the high pressure heater in turn. (16), the boiler (17) generates main steam, the main steam enters the high pressure cylinder (18) to expand and perform work to generate cold reheat steam, and then the boiler (17) raises the temperature to generate hot reheat steam, and then enters the medium pressure in turn a cylinder (19), a low-pressure cylinder (20) and a condenser (11), in which the steam condenses into condensed water; Energy release mode: turn on the energy release mode when the grid electricity peaks and lack of power supply, close the first valve (7) and the second valve (8), open the third valve (9) and the fourth valve (10); the air side , the low-temperature liquid air flows out from the liquid air storage tank (4), and after the cold energy is recovered by the gas-liquid conversion device (3), normal temperature and high pressure air is generated, and then enters the heater (5) to increase the temperature, and then enters the expander (6) for expansion The outlet of the expander (6) is normal pressure and normal temperature air, which is discharged into the surrounding environment; on the water side, part or all of the steam at the outlet of the medium pressure cylinder (19) enters the heater (5) through the third valve (9). ) heats the air, and then enters the condensate pump (12) through the fourth valve (10), and the rest of the steam directly enters the low-pressure cylinder (20) to continue working, and at the outlet of the condensate pump (12) all the condensed water enters the first-stage low-pressure heater (13). -1), the circulation process of water in other equipment is the same as the energy storage mode.

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