Liquid air energy storage system coupled with air separation and dry ice preparation

Abstract

The utility model discloses a liquid air energy storage system coupled with air separation and dry ice preparation, which comprises an air compression liquefaction subsystem, a cold energy gradient utilization subsystem, an air expansion power generation subsystem and a heat storage subsystem, the air compression and liquefaction subsystem, the cold energy gradient utilization subsystem and the expansion power generation subsystem are sequentially connected through a compression and liquefaction pipeline and an expansion power generation pipeline, and the heat storage subsystem is connected with the air compression and liquefaction subsystem and the air expansion power generation subsystem through a heat storage circulation pipeline. The cold energy gradient utilization subsystem is arranged to replace an existing low-temperature cold storage unit, the liquid air energy storage system is coupled with the air separation unit and the dry ice preparation unit, liquid air cold energy gradient utilization is achieved, and meanwhile energy consumption and construction cost of the air separation system are reduced. The power generation stability of the liquid air energy storage system is guaranteed, and the comprehensive efficiency and the environmental protection property of the liquid air energy storage system are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid air energy storage systems, and particularly relates to a liquid air energy storage system coupled with air separation and dry ice preparation. Background Art

[0002] The technology of liquid air cold energy storage and utilization is the core to improve the efficiency of liquid air energy storage systems. Most existing liquid air energy storage systems adopt cryogenic energy storage technologies, using solid energy storage packed beds or liquid and phase change energy storage technologies to store the cold energy generated by the evaporation of liquid air during the energy release process, and using the stored cold energy for air liquefaction during the energy storage process. However, the existing solid energy storage packed bed technology has low energy storage efficiency, and the liquid and phase change energy storage technologies have poor economy and low safety. Content of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide a liquid air energy storage system coupled with air separation and dry ice preparation, so as to solve the problems of low comprehensive efficiency of existing liquid air energy storage systems, high energy consumption of air separation systems and dry ice manufacturing systems, ensure the improvement of the power generation stability and comprehensive efficiency of the liquid air energy storage system, and also improve the economy and environmental protection of the overall operation of the system.

[0004] To solve the above technical problems, the technical solutions adopted by the utility model are as follows.

[0005] A liquid air energy storage system coupled with air separation and dry ice preparation includes an air compression and liquefaction subsystem for consuming off-peak electricity during the energy storage process to convert air into liquid air and store it, a cold energy cascade utilization subsystem for recovering and utilizing the cold energy of liquid air during the energy release process, an air expansion power generation subsystem for generating electricity by using the air to expand and do work under increased pressure and temperature during the energy release process, and a heat storage subsystem for recovering the compression heat in the air compression and liquefaction subsystem during the energy storage process and transferring the stored heat to the air expansion power generation subsystem to heat the air during the energy release process. The air compression and liquefaction subsystem, the cold energy cascade utilization subsystem and the expansion power generation subsystem are sequentially connected through a compression liquefaction pipeline and an expansion power generation pipeline, and the heat storage subsystem is connected to the air compression and liquefaction subsystem and the air expansion power generation subsystem respectively through a heat storage circulation pipeline.

[0006] The above-mentioned liquid air energy storage system coupled with air separation and dry ice preparation, the air compression and liquefaction subsystem includes a compression purification unit and a pressurization liquefaction unit connected by a compression and liquefaction pipeline, and the compression and purification unit and the pressurization and liquefaction unit are connected by a three-way valve; the compression and purification unit includes a raw material compressor, a first cooler, a precooler, and an air purification device connected in sequence through the compression and liquefaction pipeline, and the raw material compressor is connected to a driving unit that provides power; the pressurization and liquefaction unit includes a circulating compressor, a second cooler, a liquefied cold box and a liquid air storage tank connected in sequence through the compression and liquefaction pipeline, and the circulating compressor is connected to the driving unit.

[0007] The above-mentioned liquid air energy storage system coupled with air separation and dry ice preparation, the cold energy cascade utilization subsystem includes an air separation unit and a dry ice preparation unit connected to the liquid air storage tank through an expansion power generation pipeline; the air separation unit includes a cryogenic pump, an air separation cold box, and a liquid storage device connected in sequence through an expansion power generation pipeline, and the cryogenic pump is connected to the outlet of the liquid air storage tank; the dry ice preparation unit includes a dry ice machine connected to the side outlet of the air separation cold box through an expansion power generation pipeline, the upper inlet of the dry ice machine is connected to the high-pressure carbon dioxide gas storage tank through a carbon dioxide transmission pipeline, and the lower outlet of the dry ice machine is connected to the dry ice insulation box.

[0008] In the above-mentioned liquid air energy storage system coupled with air separation and dry ice preparation, a regulating valve for regulating the flow of carbon dioxide inside the transmission pipeline is provided on the carbon dioxide transmission pipeline between the high-pressure carbon dioxide storage tank and the dry ice machine.

[0009] The above-mentioned liquid air energy storage system coupled with air separation and dry ice preparation, the air expansion power generation subsystem includes a cold fluid conveying device, a first heater, a first expansion generator, a second heater, and a second expansion generator connected in sequence through an expansion power generation pipeline, wherein the cold fluid conveying device is connected to the dry ice machine; the first expansion generator and the second expansion generator are coaxially connected in series, and the transmission shaft between the first expansion generator and the second expansion generator is connected to the generator.

[0010] The above-mentioned liquid air energy storage system coupled with air separation and dry ice preparation, the heat storage subsystem includes a heat storage device, and a first heat fluid transportation device is arranged on the heat storage circulation pipeline between the heat storage device and the air compression and liquefaction subsystem; a second heat fluid transportation device is arranged on the heat storage circulation pipeline between the heat storage device and the air expansion and power generation subsystem.

[0011] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0012] The utility model provides a liquid air energy storage system coupled with air separation and dry ice preparation. By setting up a cold energy cascade utilization subsystem to replace the low-temperature cold storage unit in the prior art, the liquid air energy storage system is coupled with the air separation unit and the dry ice preparation unit. The liquid air energy storage system not only provides cold energy for air separation but also can be used as a raw material for air separation when there is sufficient liquid air, reducing the energy consumption of the air separation unit. At the same time, the remaining low-grade cold energy can be used to manufacture dry ice, meeting the requirement of zero carbon emissions for dry ice manufacturing. While realizing the cascade utilization of liquid air cold energy, it reduces the energy consumption and construction cost of the air separation system, ensures the stability of power generation of the liquid air energy storage system, and improves the comprehensive efficiency and environmental protection of the liquid air energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the specific structure of the present utility model.

[0014] Wherein: 101. Feed compressor, 102. First cooler, 103. Pre-cooler, 104. Air purification device, 105. Three-way valve, 106. Circulation compressor, 107. Second cooler, 108. Liquefaction cold box, 109. Liquid air storage tank, 201. Low-temperature pump, 202. Air separation cold box, 203. Liquid storage device, 204. First switch valve, 205. Second switch valve, 301. High-pressure carbon dioxide gas storage tank, 302. Regulating valve, 303. Dry ice machine, 304. Dry ice insulation box, 401. Cold fluid conveying equipment, 402. First heater, 403. First expansion generator, 404. Second heater, 405. Second expansion generator, 501. Heat storage device, 502. First hot fluid conveying equipment, 503. Second hot fluid conveying equipment, M. Driving unit, G. Generator, A1. Compression and liquefaction pipeline, B1. Expansion power generation pipeline, C1. Carbon dioxide conveying pipeline, H1. Heat storage circulation pipeline, L1. Air separation pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The present utility model will be further described in detail below in conjunction with the drawings and specific embodiments.

[0016] A liquid air energy storage system coupled with air separation and dry ice preparation, as Figure 1 shown, includes an air compression and liquefaction subsystem, a cold energy cascade utilization subsystem, an air expansion power generation subsystem, and a heat storage subsystem. The air compression and liquefaction subsystem, the cold energy cascade utilization subsystem, and the expansion power generation subsystem are sequentially connected through a compression and liquefaction pipeline A1 and an expansion power generation pipeline B1. The heat storage subsystem is connected to the air compression and liquefaction subsystem and the air expansion power generation subsystem respectively through a heat storage circulation pipeline H1.

[0017] The air compression and liquefaction subsystem is used to consume off-peak electricity during the energy storage process to convert air into liquid air and store it.

[0018] The cold energy cascade utilization subsystem is used to recover and utilize the cold energy of liquid air during the energy release process.

[0019] The air expansion power generation subsystem is used to generate electricity by using the air to boost pressure, increase temperature and expand to do work during the energy release process.

[0020] The heat storage subsystem is used to recover the compression heat in the air compression and liquefaction subsystem during the energy storage process, and transfer the stored heat to the air expansion power generation subsystem to heat the air during the energy release process.

[0021] The air compression and liquefaction subsystem includes a compression and purification unit and a pressurization and liquefaction unit connected by a compression and liquefaction pipeline A1. The compression and purification unit and the pressurization and liquefaction unit are connected by a three-way valve 105.

[0022] The compression and purification unit includes a raw material compressor 101, a first cooler 102, a precooler 103, and an air purification device 104 connected in sequence by a compression and liquefaction pipeline A1. The raw material compressor 101 is connected to a driving unit M that provides power.

[0023] The raw material compressor 101 is a single-stage or multi-stage low-pressure compressor. When a multi-stage compressor is used, the number of first coolers 102 is the same as the total number of stages of the raw material compressor 101.

[0024] The air purification device 104 operates in a working mode of two towers in parallel or a single tower in intermittent operation.

[0025] The pressurization and liquefaction unit includes a recycle compressor 106, a second cooler 107, a liquefaction cold box 108, and a liquid air storage tank 109 connected in sequence by a compression and liquefaction pipeline A1. The recycle compressor 106 is connected to the driving unit M.

[0026] The liquefaction cold box 108 uses a liquefaction method of throttling expansion by a throttle valve or isentropic expansion of a cryogenic expander combined with throttling expansion by a throttle valve.

[0027] The recycle compressor 106 is a single-stage or multi-stage high-pressure compressor. When a multi-stage compressor is used, the number of second coolers 107 is the same as the total number of stages of the recycle compressor 106.

[0028] The driving unit M is a driving motor or a wind turbine. When the driving unit M is used as a driving motor, it generally uses one or more of off-peak electricity from a conventional power station, nuclear power, wind power, solar power, hydropower, or tidal power as the power source.

[0029] The cold energy cascade utilization subsystem includes an air separation unit and a dry ice preparation unit connected to the liquid air storage tank 109 via an expansion power generation pipeline B1.

[0030] The air separation unit includes a cryogenic pump 201, an air separation cold box 202, and a liquid storage device 203 which are sequentially connected via an expansion power generation pipeline B1. The cryogenic pump 201 is connected to the outlet of the liquid-air storage tank 109. The cryogenic pump is a reciprocating, centrifugal or hybrid type.

[0031] The liquid air storage tank 109 is mainly used to store liquefied air, i.e., liquid air, and to provide cooling capacity or raw materials for the air separation unit.

[0032] The upper inlet of the air separation cold box 202 is connected to the three-way valve 105 through the air separation pipeline L1, and the lower outlet of the air separation cold box 202 is connected to the liquid storage device 203 through the air separation pipeline L1.

[0033] The dry ice preparation unit includes a dry ice machine 303 connected to the side outlet of the air separation cold box 202 through an expansion power generation pipeline B1, the upper inlet of the dry ice machine 303 is connected to the high-pressure carbon dioxide storage tank 301 through a carbon dioxide delivery pipeline C1, and the lower outlet of the dry ice machine 303 is connected to a dry ice insulation box 304, which can store the produced dry ice in time.

[0034] A regulating valve 302 is provided on the carbon dioxide delivery pipeline C1 between the high-pressure carbon dioxide storage tank 301 and the dry ice machine 303 to adjust the flow of carbon dioxide inside the delivery pipeline.

[0035] The expansion power generation pipeline B1 leading to the air separation cold box 202 is respectively provided with a first switch valve 204 and a second switch valve 205 for controlling the flow direction of liquid air, which can timely adjust the flow direction of liquid air according to the amount of liquid air in the liquid air storage tank 109.

[0036] The air expansion power generation subsystem includes a cold fluid delivery device 401, a first heater 402, a first expansion generator 403, a second heater 404, and a second expansion generator 405 which are sequentially connected via an expansion power generation pipeline B1, wherein the cold fluid delivery device 401 is connected to the dry ice machine 303.

[0037] The first expansion generator 403 and the second expansion generator 405 are coaxially connected in series, and the transmission shaft between the first expansion generator 403 and the second expansion generator 405 is connected to the generator G.

[0038] The expansion generator is a single-stage or multi-stage generator and is consistent with the total number of compression stages of the compressor in the compression purification unit, and the number of the heaters is consistent with the total number of stages of the expansion generator.

[0039] The heat storage subsystem includes a heat storage device 501, which is connected to the second cooler 107 and the first cooler 102 via a heat storage circulation pipeline H1 to form a circulation loop, and the heat storage device 501 is connected to the second heater 404 and the first heater 402 via a heat storage circulation pipeline H1 to form a circulation loop.

[0040] A first thermal fluid transport device 502 is provided on the heat storage circulation pipeline H1 between the heat storage device 501 and the second cooler 107 .

[0041] A second thermal fluid transport device 503 is provided on the heat storage circulation pipeline H1 between the heat storage device 501 and the second heater 404 .

[0042] The heat storage form of the heat storage device 501 is one or more of sensible heat, latent heat or chemical reaction heat. The heat storage medium used in the heat storage device 501 is water, paraffin, biomass oil, inorganic crystalline hydrated salt, molten salt, metal and its alloy, organic fatty acid, stone, rock or concrete, and the heat storage medium is stored in an insulating container.

[0043] The cold fluid conveying device 401, the first hot fluid conveying device 502, and the second hot fluid conveying device 503 are pumps, compressors, or fans.

[0044] The raw material compressor 101, the circulating compressor 106, the first expansion generator 403, and the second expansion generator 405 are piston type, axial flow type, centrifugal type, screw type, or hybrid type.

[0045] The first cooler 102, the precooler 103, the first heater 402, and the second heater 404 are of plate-fin type, coiled tube type, printed circuit board type, shell and tube type, plate type, or hybrid type.

[0046] The medium flowing through the compression and liquefaction pipeline A1 and the expansion and power generation pipeline B1 is gaseous or liquid air.

[0047] The media flowing in the air separation pipeline L1 are clean air and separated and liquefied liquid oxygen, liquid nitrogen and liquid argon.

[0048] The medium flowing in the carbon dioxide transmission pipeline C1 is high-pressure gaseous carbon dioxide.

[0049] The medium flowing in the heat storage circulation pipeline H1 is ethylene glycol.

[0050] The working principle of the utility model is:

[0051] The heat storage system includes two processes: energy storage and energy release. During the energy storage process, the compression and liquefaction subsystem and the heat storage subsystem are in working condition. During the energy release process, the compression and purification unit of the compression and liquefaction subsystem, the cold energy cascade utilization subsystem, the air expansion and power generation subsystem and the heat storage subsystem are in working condition.

[0052] Specifically, during the energy storage process, after being compressed and cooled by the raw material compressor 101 and the first cooler 102, the air first enters the precooler 103 for precooling, and then enters the air purification device 104 to remove water and carbon dioxide.

[0053] Then, open the interface on one side of the three-way valve 105 connected to the pressurization and liquefaction unit, send the treated clean air to the second compressor 106 and the second cooler 107 for re-pressurization and cooling, and then send it to the liquefaction cold box 108 for further cooling, expansion and liquefaction, and then store it in the liquid air storage tank 109.

[0054] During the energy storage process, the heat storage device 501 recovers compression heat through the first cooler 102, the second cooler 107 and the heat storage circulation pipeline H1.

[0055] During the energy release process, the three-way valve 105 interface connected to the pressurized liquefaction unit is closed, and the other two interfaces are opened. The clean air from which water and carbon dioxide are removed after being processed by the compression purification unit is sent to the air-cooling sub-box 202 through the air separation pipeline L1. At the same time, the heat storage subsystem completes the recovery of compression heat during the purification process through the heat storage circulation pipeline H1.

[0056] Normally, the first switch valve 204 is normally open, and the second switch valve 205 is normally closed. The liquid air in the liquid air storage tank 109 is first pressurized by the cryogenic pump 201 and then sequentially enters the air separation cold box 202 and the dry ice machine 303 to release only cold energy. The clean air with high-grade cold energy entering the air cooling box 202 provides cold energy for air liquefaction separation and then becomes low-grade cold energy. The low-grade cold energy is used to complete the preparation of dry ice.

[0057] When the amount of liquid air in the liquid air storage tank 109 is excessive, the second switch valve 205 is opened and the first switch valve 204 is closed, and the excess liquid air enters the air separation cold box 202 for air separation as both cooling capacity and raw material.

[0058] Then, the air after cooling or the remaining air after separation is pressurized again by the cold fluid conveying device 401 and then passes through the first heater 402, the first expansion generator 403, the second heater 404, and the second expansion generator 405 in sequence to heat up and expand before being supplied to the generator G for power generation.

[0059] During the process of releasing cold energy into the dry ice machine 303, the regulating valve 302 is opened to transport carbon dioxide in the high-pressure carbon dioxide storage tank 301 into the dry ice machine 303 to produce dry ice, and the dry ice is stored in the dry ice insulation box 304.

[0060] During the power generation process and the dry ice preparation process, the heat storage subsystem releases heat through the first heater 402 and the second heater 404 to heat the inlet air of the expansion generator.

[0061] The present utility model provides a liquid air energy storage system coupled with air separation and dry ice preparation. By setting up a cold energy cascade utilization subsystem to replace the low-temperature cold storage unit in the prior art, the liquid air energy storage system is coupled with the air separation unit and the dry ice preparation unit. The liquid air energy storage system not only provides cold energy for air separation but also can be used as a raw material for air separation when there is sufficient liquid air, reducing the energy consumption of the air separation unit. At the same time, the remaining low-grade cold energy can be used to manufacture dry ice, meeting the requirement of zero carbon emission for dry ice production. While realizing the cascade utilization of liquid air cold energy, it reduces the energy consumption and construction cost of the air separation system, ensures the stability of power generation of the liquid air energy storage system, and improves the comprehensive efficiency and environmental friendliness of the liquid air energy storage system.

Claims

1. A liquid air energy storage system coupled with air separation and dry ice preparation, characterized in that: It includes an air compression and liquefaction subsystem for consuming off-peak electricity during the energy storage process to convert air into liquid air and store it, a cold energy cascade utilization subsystem for recycling the cold energy of liquid air during the energy release process, an air expansion power generation subsystem for using the air to boost pressure, increase temperature and expand to do work and generate electricity during the energy release process, and a heat storage subsystem for recovering the compression heat in the air compression and liquefaction subsystem during the energy storage process and transferring the stored heat to the air expansion power generation subsystem to heat the air during the energy release process. The air compression and liquefaction subsystem, the cold energy cascade utilization subsystem, and the expansion power generation subsystem are sequentially connected through a compression and liquefaction pipeline (A1) and an expansion power generation pipeline (B1). The heat storage subsystem is connected to the air compression and liquefaction subsystem and the air expansion power generation subsystem respectively through a heat storage circulation pipeline (H1).

2. The liquid air energy storage system coupled with air separation and dry ice preparation according to claim 1, wherein: The air compression and liquefaction subsystem includes a compression and purification unit and a pressurization and liquefaction unit connected through a compression and liquefaction pipeline (A1). The compression and purification unit and the pressurization and liquefaction unit are connected through a three-way valve (105). The compression and purification unit includes a raw material compressor (101), a first cooler (102), a precooler (103), and an air purification device (104) connected in sequence through a compression and liquefaction pipeline (A1). The raw material compressor (101) is connected to a driving unit (M) that provides power. The pressurization and liquefaction unit includes a circulation compressor (106), a second cooler (107), a liquefaction cold box (108), and a liquid air storage tank (109) connected in sequence through a compression and liquefaction pipeline (A1). The circulation compressor (106) is connected to the driving unit (M).

3. A liquid air energy storage system coupled with air separation and dry ice preparation according to claim 2, characterized in that: The cold energy cascade utilization subsystem includes an air separation unit and a dry ice preparation unit connected to the liquid air storage tank (109) through an expansion power generation pipeline (B1). The air separation unit includes a cryogenic pump (201), an air separation cold box (202), a liquid storage device (203) connected in sequence through an expansion power generation pipeline (B1), and a first switch valve (204) and a second switch valve (205) for controlling the flow direction of liquid air on the expansion power generation pipeline (B1) leading to the inside of the air separation cold box (202). The cryogenic pump (201) is connected to the outlet of the liquid air storage tank (109). The dry ice preparation unit includes a dry ice machine (303) connected to the side outlet of the air separation cold box (202) through an expansion power generation pipeline (B1). The upper inlet of the dry ice machine (303) is connected to a high-pressure carbon dioxide gas storage tank (301) through a carbon dioxide delivery pipeline (C1). The outlet at the lower part of the dry ice machine (303) is connected to a dry ice insulation box (304).

4. A liquid air energy storage system coupled with air separation and dry ice preparation according to claim 3, characterized in that: A regulating valve (302) for regulating the flow rate of carbon dioxide inside the delivery pipeline is provided on the carbon dioxide delivery pipeline (C1) between the high-pressure carbon dioxide gas storage tank (301) and the dry ice machine (303).

5. The liquid air energy storage system coupled with air separation and dry ice preparation according to claim 3, characterized in that: The air expansion power generation subsystem includes a cold fluid delivery device (401), a first heater (402), a first expansion generator (403), a second heater (404), and a second expansion generator (405) that are sequentially connected through an expansion power generation pipeline (B1), wherein the cold fluid delivery device (401) is connected to a dry ice machine (303); the first expansion generator (403) and the second expansion generator (405) are coaxially connected in series, and a transmission shaft between the first expansion generator (403) and the second expansion generator (405) is connected to a generator (G).

6. The liquid air energy storage system coupled with air separation and dry ice preparation according to claim 1, characterized in that: The heat storage subsystem includes a heat storage device (501), and a first heat fluid delivery device (502) is provided on a heat storage circulation pipeline (H1) located between the heat storage device (501) and the air compression and liquefaction subsystem; a second heat fluid delivery device (503) is provided on the heat storage circulation pipeline (H1) located between the heat storage device (501) and the air expansion power generation subsystem.

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