Full-section air supply type compressed air energy storage system and operation mode

Abstract

The invention discloses a full-section air supply type compressed air energy storage system, which belongs to a compressed air energy storage system and comprises a compressed air storage module, an expansion acting module connected with an outlet of the compressed air storage module, and an air compression module connected with an inlet of the compressed air storage module, a multi-stage cooler is arranged between the compressed air storage module and the air compression module, a multi-stage heater is arranged between the compressed air storage module and the expansion acting module, the compressed air storage module comprises a plurality of air storage pipes connected in parallel, and an inlet of each air storage pipe is connected with an outlet of the air compression module. The multi-section parallel air storage pipe is adopted as the air storage device of the compressed air energy storage system, the storage pressure is high, the sealing performance is good, the air storage device can be flexibly installed and arranged and is not limited by special geographical conditions, an integrated pipe network is convenient to form a scale, and simultaneous air injection and batched air production can be achieved; and the system operation efficiency can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of compressed air energy storage systems, and in particular to a full-stage air-supplementing type compressed air energy storage system and an operation mode thereof. Background Art

[0002] In recent years, with the energy conservation and emission reduction and the high proportion of renewable energy adopted, the problems of insufficient new energy supply and waste of surplus electricity have become prominent. Therefore, compressed air energy storage systems have been used more and more widely. By compressing air to store excess electrical energy, when needed, the high-pressure air is released through the expander to generate electricity, which can effectively meet the urgent needs for efficiency, safety and economy of power systems and regional energy systems after large-scale access to renewable energy.

[0003] The energy storage devices of existing compressed air energy storage systems all use underground cave gas storage methods, which have high requirements on geographical conditions and are difficult to promote on a large scale. Once a gas leak occurs, it is difficult to monitor. At the same time, the geological environment of the underground cave rock layer is complex, and the safe and stable operation is difficult to guarantee. It can only operate within a smaller pressure range. When the pressure is lower than the rated working power of the expander, the expander cannot meet the maximum power operation, which will lead to reduced power generation efficiency and reduced overall energy efficiency of the system. In this case, air replenishment is generally used to increase the expander inlet flow rate. This will inevitably require the addition of a set of air replenishment compressor equipment, which will greatly increase the construction cost of the entire system, and thus increase the operation and maintenance cost. Summary of the invention

[0004] In response to the above problems, the present invention provides a full-stage air-supplementing compressed air energy storage system and operation mode, which can realize batch gas production and full-stage air replenishment of the expander, fully utilize gas storage resources, and improve the overall operation efficiency of the system.

[0005] The technical solution of the present invention is:

[0006] A full-stage air-supplementing compressed air energy storage system, comprising a compressed air storage module, an expansion working module connected to the outlet of the compressed air storage module, and an air compression module connected to the inlet of the compressed air storage module, a multi-stage cooler is arranged between the compressed air storage module and the air compression module, a multi-stage heater is arranged between the compressed air storage module and the expansion working module, the compressed air storage module comprises a plurality of parallel air storage pipes, the inlet of each air storage pipe is connected to the outlet of the air compression module, and the outlet of each air storage pipe is connected to the inlet of the expansion working module;

[0007] An air injection valve is arranged at the inlet of each air storage pipe, and a pressure sensor and an air outlet valve are arranged at the outlet.

[0008] A cold storage tank and a heat storage tank are arranged between the multi-stage heater and the multi-stage cooler, the outlet of the cold storage tank is communicated with the heat exchange medium inlet of the multi-stage heater, the inlet of the cold storage tank is communicated with the heat exchange medium outlet of the multi-stage heater, the outlet of the heat storage tank is communicated with the heat exchange medium inlet of the multi-stage heater, and the inlet of the heat storage tank is communicated with the heat exchange medium outlet of the multi-stage cooler.

[0009] The air compression module comprises compressors connected in series with the number of stages corresponding to the multi-stage coolers, and each compressor outlet is connected to a cooler.

[0010] The expansion work module comprises expanders connected in series with the number of stages corresponding to the multi-stage heaters, and each expander inlet is connected to a heater.

[0011] A mainstream gas distribution device and a supplementary gas distribution device are arranged between the compressed air storage module and the multi-stage heater. The air outlet valve at each outlet of the air storage pipe is a three-way valve. The air outlet valve is connected to the air storage pipe, the mainstream gas distribution device, and the supplementary gas distribution device. The outlets of the mainstream gas distribution device and the supplementary gas distribution device are connected to the expansion working module.

[0012] The system also includes a controller, which is signal-connected to the gas injection valve, pressure sensor, gas outlet valve, mainstream gas distribution device, and supplementary gas distribution device of each gas storage pipe.

[0013] The gas storage pipe is a steel pipe.

[0014] A full-stage air-supplementing compressed air energy storage system operates as follows:

[0015] S1, gas injection stage, the air compression module injects high-pressure air into the compressed air storage module, and stops gas injection when the air storage pipe pressure reaches the first set pressure;

[0016] S2, the first working stage of gas collection, each gas storage pipe of the compressed air storage module is used as the mainstream gas pipe to supply gas to the expansion working module in turn, and when the pressure of all gas storage pipes reaches the second set pressure, the second working stage of gas collection is entered;

[0017] S3, the second working stage of gas production, the compressed air storage module is divided into a mainstream gas pipe group and an air supply pipe group, the mainstream gas pipe group serves as the mainstream gas pipe to supply gas to the expansion working module, and the air supply pipe group serves as the air supply pipe to supply gas to the expansion working module. When the pressure of the mainstream gas pipe group reaches the third set pressure, gas production is stopped.

[0018] The beneficial effects of the present invention are:

[0019] 1. Use multiple parallel gas storage pipes as the gas storage device of the compressed air energy storage system. It has high storage pressure, good sealing, and can be flexibly installed and arranged. It is not restricted by special geographical conditions and is convenient for integrating the pipe network to form a scale. At the same time, each section of the steel pipe is installed independently in parallel, which can be used for fixed-point screening and troubleshooting, diagnosis and maintenance, and replacement of devices, thereby reducing system maintenance costs and reducing existing safety hazards.

[0020] 2. The operation method adopts the operation method of simultaneous gas injection and batch gas extraction. When the system releases energy, through two gas extraction working stages, it can realize the full-section gas replenishment of the expansion module, enhance the variable pressure working condition operation capability of the system expander, maintain its stable operation under rated working conditions, ensure the full power generation of the generator at all times, and improve the system operation efficiency;

[0021] 3. The air storage module of the compressed air storage system can realize the self-air replenishment operation state of the system through the variable working condition regulation of the control module. There is no need to build an additional air replenishment compressor. The high-pressure air pressure energy in the air storage pipe can be fully utilized, which can reduce the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of a full-stage air-supplementing compressed air energy storage system according to an embodiment of the present invention;

[0023] Figure 2 It is a flow chart of an operation method of a full-stage air-supplementing compressed air energy storage system according to an embodiment of the present invention;

[0024] Figure 3 It is a flow chart of the operation of the gas collection phase of a full-stage air-supplementing compressed air energy storage system described in an embodiment of the present invention.

[0025] Description of reference numerals:

[0026] 1 is a compressed air storage module, 2 is an expansion work module, 3 is an air compression module, 4 is a multi-stage cooler, 5 is a multi-stage heater, 6 is a cold storage tank, 7 is a heat storage tank, 8 is a mainstream gas distribution device, 9 is a supplementary gas distribution device, 11 is an air storage pipe, 111 is an air injection valve, 112 is a pressure sensor, and 113 is an air outlet valve. DETAILED DESCRIPTION

[0027] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0028] Example:

[0029] like Figure 1-Figure 3As shown, a full-stage air-supplementing compressed air energy storage system comprises a compressed air storage module 1, an expansion working module 2 connected to the outlet of the compressed air storage module 1, an air compression module 3 connected to the inlet of the compressed air storage module 1, a multi-stage cooler 4 is arranged between the compressed air storage module 1 and the air compression module 3, a multi-stage heater 5 is arranged between the compressed air storage module 1 and the expansion working module 2, and the compressed air storage module 1 comprises a plurality of parallel air storage pipes 11, the inlet of each air storage pipe 11 is connected to the outlet of the air compression module 3, and the outlet of each air storage pipe 11 is connected to the inlet of the expansion working module 2;

[0030] An air injection valve 111 is provided at the inlet of each air storage pipe 11 , and a pressure sensor 112 and an air outlet valve 113 are provided at the outlet.

[0031] The working principle of the above technical solution is as follows:

[0032] When the air compression module 3 starts working, the heat exchange medium flows through each cooler in turn, and recovers its heat through heat exchange with the high-temperature and high-pressure air through the cooler, and is finally stored for standby use; when the expansion work module 2 starts working, the heat exchange medium flows through each heater in turn, and heats the low-temperature and low-pressure air through the heater, and the heating medium after heat exchange is stored for standby use. The air compression module 3 stores the compressed air in the compressed air storage module 1, and controls the injection and outlet of air through the injection valve 111, the sensor 112 and the outlet valve 113. It can be flexibly installed and arranged, is not restricted by special geographical conditions, and is convenient for the integrated pipeline network to form a scale. The expansion work module 2 is connected to the generator, and after the expansion work, it drives the generator to generate electricity.

[0033] A cold storage tank 6 and a heat storage tank 7 are arranged between the multistage heater 5 and the multistage cooler 4. The outlet of the cold storage tank 6 is communicated with the heat exchange medium inlet of the multistage heater 5, the inlet of the cold storage tank 6 is communicated with the heat exchange medium outlet of the multistage cooler 4, the outlet of the heat storage tank 7 is communicated with the heat exchange medium inlet of the multistage heater 5, the inlet of the heat storage tank 7 is communicated with the heat exchange medium outlet of the multistage cooler 4, the cold storage tank 6, the heat storage tank 7 and the inner flow section of the multistage cooler 4 and the multistage heater 5 form a heat exchange circulation loop, the heat exchange medium can be stored in the cold storage tank 6 and the heat storage tank 7 to ensure the reliability of the system.

[0034] The air compression module 3 includes compressors corresponding to 4 stages of multi-stage coolers connected in series, and each compressor outlet is connected to a cooler. The expansion work module 2 includes expanders corresponding to 5 stages of multi-stage heaters connected in series, and each expander inlet is connected to a heater. The number of compressors and expanders can be adjusted according to the needs of on-site operations.

[0035] A mainstream gas distribution device 8 and a supplementary gas distribution device 9 are arranged between the compressed air storage module 1 and the multi-stage heater 5. The outlet valve 113 at the outlet of each gas storage pipe 11 is a three-way valve. The outlet valve 113 is connected to the gas storage pipe 11, the mainstream gas distribution device 8, and the supplementary gas distribution device 9. The outlets of the mainstream gas distribution device 8 and the supplementary gas distribution device 9 are connected to the expansion work module 2. The mainstream gas distribution device 8 is connected to the heater inlet through the mainstream gas valve to provide high-pressure air for the expander. The supplementary gas distribution device 9 is connected to the inlet of each heater through the supplementary gas bypass. The supplementary gas bypass is provided with a supplementary gas valve, and the number of supplementary gas valves depends on the number of expanders. In addition, electromagnetic throttle valves are arranged inside the mainstream gas distribution device 8 and the supplementary gas distribution device 9 to facilitate the regulation of the gas flow under variable working conditions and ensure the stability of the generator power generation.

[0036] The system also includes a controller, which is connected to the gas injection valve 111, pressure sensor 112, gas outlet valve 113, mainstream gas distribution device 8, and gas supply distribution device 9 of each gas storage pipe 11. The controller can control the stability of the operation of the entire system, play a role in speed regulation, monitoring and protection, and ensure the safety of the use of the entire system.

[0037] The gas storage pipe 11 is a steel pipe with high pressure resistance and is safe and reliable to use.

[0038] A full-stage air-supplementing compressed air energy storage system, wherein the first set pressure X1 of the system is the maximum air storage pressure of the air storage pipe, the second set pressure X2 is the rated working pressure of the expansion module, the third set pressure X3 is the minimum air storage pressure of the air storage pipe, and the real-time monitoring pressure is the mainstream gas steel pipe pressure. The first set pressure X1> the second set pressure X2> the third set pressure X3. The control module can automatically switch the gas production working stage through the pressure data received by the pressure sensor until the gas production is completed.

[0039] This embodiment adopts a system with three-stage compression and five gas storage pipes, and the operation mode is as follows:

[0040] S1, gas injection stage, the air compression module injects high-pressure air into the compressed air storage module, and stops gas injection when the air storage pipe pressure reaches the first set pressure X1;

[0041] Specifically, when the gas injection is in operation, the system enters the gas injection stage, the motor starts to drive the multi-stage compressor to work, and the normal-pressure air is pressurized step by step through the first-stage compressor, the second-stage compressor, and the third-stage compressor. At this time, the control module controls the gas injection valve of the first gas storage pipe to open, and the high-pressure air enters the first gas storage pipe for storage. When the first pressure sensor detects that the air pressure inside the steel pipe reaches the first set pressure X1, the first gas injection valve is closed, and the gas injection in the first gas storage pipe is completed; then, the second gas injection valve is opened, and the high-pressure air enters the second gas storage pipe for storage. When the second pressure sensor detects that the air pressure reaches the first set pressure X1, the second gas injection valve is closed, and the gas injection in the second gas storage pipe is completed; similarly, the third gas injection valve, the fourth gas injection valve, and the fifth gas injection valve are opened in sequence to inject gas into the third gas storage pipe, the fourth gas storage pipe, and the fifth gas storage pipe. When the fifth pressure sensor detects that the pressure in each tank has reached the first set pressure X1, the gas injection in the fifth gas storage pipe is completed, that is, the gas injection of the entire energy storage module is completed, and the gas injection valves are closed.

[0042] S2, the first working stage of gas collection, each gas storage pipe of the compressed air storage module is used as the mainstream gas pipe to supply gas to the expansion working module in turn, and when the pressure of all gas storage pipes reaches the second set pressure X2, the second working stage of gas collection is entered;

[0043] Specifically, when gas production is in operation, the system first enters the first gas production working stage, and each gas storage pipe of the energy storage module serves as the mainstream gas pipe in turn to supply gas to the expansion module. At this time, the control module controls the valve of the first three-way valve connected to the mainstream gas distribution device to open, and the mainstream gas valve opens. At the same time, the control module adjusts the opening size of the electromagnetic throttle valve inside the mainstream gas distribution device, and the expansion module adopts a throttling operation mode. During the continuous gas production process, the air pressure in the first gas storage pipe gradually decreases from the first set pressure, and the opening size of the electromagnetic throttle valve inside the mainstream gas distribution device gradually increases, increasing the inlet flow rate of the expander to ensure that the generator of the expansion module generates electricity at the rated power and the power generation efficiency reaches the maximum. When the first pressure sensor detects that the steel pipe outlet When the pressure reaches the second set pressure, the first three-way valve is closed, and gas production from the first gas storage pipe is completed; then, the valve of the second three-way valve connected to the mainstream gas distribution device is opened, and the control module readjusts the opening size of the electromagnetic throttle valve inside the mainstream gas distribution device to continuously supply gas to the expansion module. When the second pressure sensor detects that the steel pipe outlet pressure reaches the second set pressure, the second three-way valve is closed, and gas production from the second gas storage pipe is completed; similarly, the third three-way valve, the fourth three-way valve, and the fifth three-way valve are opened in sequence to produce gas. When the fifth pressure sensor 82 detects that the pressure in the tank reaches the second set pressure, gas production from the fifth gas storage pipe is completed, that is, the first working stage of gas production from the entire energy storage module is completed, and then the control module adjusts to enter the second working stage of gas production.

[0044] At the same time, the heat exchange module works synchronously, the solenoid valve installed in front of the heater opens, and the high-temperature heat exchange medium in the heat storage tank enters the heater to exchange heat with the inlet air of each stage of expanders, thereby increasing the inlet air temperature of the expander to reach the rated working temperature.

[0045] S3, the second working stage of gas production, the compressed air storage module is divided into a mainstream air pipe group and an air supply pipe group, the mainstream air pipe group serves as the mainstream air pipe to supply air to the expansion working module, and the air supply pipe group serves as the air supply pipe to supply air to the expansion working module. When the pressure of the mainstream air pipe group reaches the third set pressure X3, gas production is stopped.

[0046] It should be noted that after the first gas production working stage is completed, since the air pressure in each gas storage pipe reaches the second set pressure, if it continues to operate, the air pressure in the steel pipe will gradually decrease, and the expansion module expander will not be able to reach the full-power operating conditions, the power generation efficiency of the expander and generator will decrease, and the overall operating efficiency of the system will be reduced.

[0047] Specifically, when the system enters the second working stage of gas production, the control module allocates the first gas storage pipe, the second gas storage pipe, and the third gas storage pipe in the gas storage module as the mainstream gas pipe group, and the fourth gas storage pipe and the fifth gas storage pipe as the air supply pipe group, wherein the mainstream gas pipe group serves as the mainstream gas pipe, and supplies gas to the expansion module through the mainstream gas distribution device, and the air supply pipe group serves as the air supply pipe, and supplies gas to the inlet of each stage of the expander module through the air supply distribution device. Specifically, the number of gas storage pipes in the mainstream gas pipe group 500 and the air supply pipe group can be adjusted according to the actual number of steel pipes and the pressure range.

[0048] During the operation of the second working stage of gas production, the control module controls the first three-way valve connected to the valve of the mainstream gas distribution device to open, the fourth three-way valve and the fifth three-way valve connected to the valve of the air supply distribution device to open, the mainstream gas valve is opened, the first-stage air supply valve, the second-stage air supply valve, and the third-stage air supply valve are opened. At the same time, the control module adjusts the electromagnetic throttle valve inside the mainstream gas distribution device to be fully open, and the air supply distribution device simultaneously supplies air to the inlet of each stage of expanders. During the continuous gas production process, the air pressure in the first gas storage pipe gradually decreases from the second set pressure, and the three electromagnetic throttle valves inside the air supply distribution device control the opening size according to the air supply flow rate required by the expanders at each stage. By increasing the expansion The inlet flow of the machine is ensured to ensure that the generator of the expansion module generates electricity at rated power during operation. When the first pressure sensor detects that the pressure of the first gas storage pipe reaches the third set pressure, the first three-way valve is closed, and the gas production of the first gas storage pipe ends; then, the valve of the second three-way valve connected to the mainstream gas distribution device is opened to continuously supply gas to the expander module. When the second pressure sensor detects that the pressure of the second gas storage pipe reaches the third set pressure, the second three-way valve is closed, and the gas production of the second gas storage pipe ends; similarly, the valve of the third three-way valve connected to the mainstream gas distribution device is opened. When the third pressure sensor detects that the pressure of the third gas storage pipe reaches the third set pressure, the third three-way valve is closed, and the gas production of the third gas storage pipe ends. Finally, when the air pressure in all gas storage pipes in the mainstream gas pipe group reaches the third set pressure, all valves are closed, the second working stage of gas production ends, and the operation of the entire system is completed.

[0049] The above-mentioned embodiments only express the specific implementation of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A full-stage air-supplementing compressed air energy storage system, comprising a compressed air storage module, an expansion work module connected to the outlet of the compressed air storage module, and an air compression module connected to the inlet of the compressed air storage module, characterized in that: A multi-stage cooler is arranged between the compressed air storage module and the air compression module, a multi-stage heater is arranged between the compressed air storage module and the expansion working module, the compressed air storage module comprises a plurality of parallel air storage pipes, the inlet of each air storage pipe is connected to the outlet of the air compression module, and the outlet of each air storage pipe is connected to the inlet of the expansion working module; An air injection valve is arranged at the inlet of each air storage pipe, and a pressure sensor and an air outlet valve are arranged at the outlet.

2. A full-stage air-supplementing compressed air energy storage system according to claim 1, characterized in that: A cold storage tank and a heat storage tank are arranged between the multi-stage heater and the multi-stage cooler, the outlet of the cold storage tank is communicated with the heat exchange medium inlet of the multi-stage heater, the inlet of the cold storage tank is communicated with the heat exchange medium outlet of the multi-stage heater, the outlet of the heat storage tank is communicated with the heat exchange medium inlet of the multi-stage heater, and the inlet of the heat storage tank is communicated with the heat exchange medium outlet of the multi-stage cooler.

3. A full-stage air-supplementing compressed air energy storage system according to claim 1, characterized in that: The air compression module comprises compressors connected in series with the number of stages corresponding to the multi-stage coolers, and each compressor outlet is connected to a cooler.

4. A full-stage air-supplementing compressed air energy storage system according to claim 1, characterized in that: The expansion work module comprises expanders connected in series with the number of stages corresponding to the multi-stage heaters, and each expander inlet is connected to a heater.

5. The full-stage air-supplementing compressed air energy storage system according to claim 1, characterized in that: A mainstream gas distribution device and a supplementary gas distribution device are arranged between the compressed air storage module and the multi-stage heater. The air outlet valve at each outlet of the air storage pipe is a three-way valve. The air outlet valve is connected to the air storage pipe, the mainstream gas distribution device, and the supplementary gas distribution device. The outlets of the mainstream gas distribution device and the supplementary gas distribution device are connected to the expansion working module.

6. A full-stage air-supplementing compressed air energy storage system according to any one of claims 1 to 5, characterized in that: The system also includes a controller, which is signal-connected to the gas injection valve, pressure sensor, gas outlet valve, mainstream gas distribution device, and supplementary gas distribution device of each gas storage pipe.

7. A full-stage air-supplementing compressed air energy storage system according to claim 1, characterized in that: The gas storage pipe is a steel pipe.

8. A full-stage air-supplementing compressed air energy storage system according to any one of claims 1 to 5, characterized in that: Here’s how to run it: S1, gas injection stage, the air compression module injects high-pressure air into the compressed air storage module, and stops gas injection when the air storage pipe pressure reaches the first set pressure; S2, the first working stage of gas collection, each gas storage pipe of the compressed air storage module is used as the mainstream gas pipe to supply gas to the expansion working module in turn, and when the pressure of all gas storage pipes reaches the second set pressure, the second working stage of gas collection is entered; S3, the second working stage of gas production, the compressed air storage module is divided into a mainstream gas pipe group and an air supply pipe group, the mainstream gas pipe group serves as the mainstream gas pipe to supply gas to the expansion working module, and the air supply pipe group serves as the air supply pipe to supply gas to the expansion working module. When the pressure of the mainstream gas pipe group reaches the third set pressure, gas production is stopped.

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