Compressed air energy storage and deep cooling air separation heat coupling system

Abstract

The utility model provides a compressed air energy storage and copious cooling air separation heat coupling system which comprises a copious cooling air separation purification system and a compressed air energy storage system, the copious cooling air separation purification system comprises a first heat exchanger, and the compressed air energy storage system comprises a heat storage tank. A first outlet of the heat storage tank is sequentially connected with a plurality of multi-stage heat exchangers in series through pipelines, a second outlet of the heat storage tank is connected with an inlet of the first heat exchanger, and an outlet pipeline of the first heat exchanger is connected with the first outlet of the heat storage tank through a three-way valve. And the heat exchange medium discharged by the first heat exchanger and the heat exchange medium discharged by the first outlet of the heat storage tank are mixed and then flow into the multi-stage heat exchanger. The defects that in the prior art, a purification system in deep cooling air separation equipment is large in energy consumption, the conversion efficiency between different energy sources in the compressed air energy storage stage is low, and consequently heat energy in the compressed air energy storage stage cannot be fully utilized can be overcome.

Description

Technical Field

[0001] The utility model relates to the technical field of compressed air energy storage, in particular to a compressed air energy storage and deep cold air separation heat coupling system. Background Art

[0002] There are many air separation equipments and the process is complicated. At present, most of the deep cold air separation purifiers are composed of two adsorption cylinders, an electric heater, a set of control valves and a control cabinet. The air passes through one of the adsorption cylinders, and the carbon dioxide and residual water vapor in the air are adsorbed in the molecular sieve and activated alumina, so that the air is purified. After working for 6 hours, the adsorbent in the adsorption cylinder will be saturated with water vapor and carbon dioxide in the air and lose its adsorption capacity. At this time, the adsorbent in this adsorption cylinder needs to be regenerated to restore its working capacity. To this end, the air is passed into another adsorption cylinder that has been regenerated, and the adsorption cylinder that has lost its adsorption capacity is transferred to the regeneration condition. During regeneration, the dirty nitrogen gas discharged from the cold box is heated to 150-180℃ by an electric heater and then sent to the adsorption cylinder to analyze the adsorbed water vapor and carbon dioxide and discharge them into the atmosphere. After the heating regeneration is completed, the electric heater is turned off and the adsorption cylinder is blown cold with regeneration gas. Through such switching and regeneration, the air out of the purifier is continuously purified. The electric heating process requires a lot of power, wastes energy, and increases production input costs.

[0003] Compressed air energy storage is a relatively advanced energy storage method in current energy storage technology. Its main feature is that it consumes electricity to store energy during low electricity consumption, and drives the generator to generate electricity through the work of the expander during peak electricity consumption. It has the advantages of large energy storage scale, long storage cycle, and low environmental pollution. It is considered to be one of the most promising large-scale power energy storage technologies. During the air compression process, the exhaust port is high-pressure and high-temperature air, which generates a large amount of heat energy, and the work of the expander requires a heat source to heat the air. Therefore, at present, general enterprises store the heat generated by the compressor compression process through a heat storage device (hot water tank), and use this part of the heat to preheat the compressed air during the power generation process, which can achieve the purpose of heat recovery, thereby achieving the purpose of improving power generation efficiency. Although the two stages have been complemented to a certain extent, the conversion efficiency between the two different energy sources is still low, resulting in the disadvantage that the heat energy in the compressed air energy storage stage cannot be fully utilized.

[0004] The problem of how to couple multiple systems to fully utilize energy and minimize energy losses during energy conversion is imminent. Utility Model Content

[0005] Therefore, the utility model provides a compressed air energy storage and cryogenic air separation heat coupling system, which can overcome the defects of large energy consumption of the purification system in the cryogenic air separation equipment in the prior art, low conversion efficiency between different energy sources in the compressed air energy storage stage, resulting in the inability to fully utilize the thermal energy in the compressed energy storage stage.

[0006] In order to solve the above problems, the utility model provides a compressed air energy storage and cryogenic air separation heat coupling system, including a compressed air energy storage system and a cryogenic air separation purification system, the cryogenic air separation purification system including a first heat exchanger, the compressed air energy storage system including a heat storage tank, the first outlet of the heat storage tank is connected in series with a plurality of multi-stage heat exchangers through a pipeline, the second outlet of the heat storage tank is connected to the inlet of the first heat exchanger, and the outlet pipeline of the first heat exchanger is connected to the first outlet of the heat storage tank through a three-way valve, so that the heat exchange medium discharged from the first heat exchanger is mixed with the heat exchange medium discharged from the first outlet of the heat storage tank and then flows into the multi-stage heat exchanger.

[0007] In some embodiments, the cryogenic air separation purification system also includes a second heat exchanger, the air inlet of the second heat exchanger is connected to the regeneration gas inlet of the cryogenic air separation purification system, the exhaust port of the second heat exchanger is connected to the air inlet of the first heat exchanger, and the heat exchange medium of the second heat exchanger is provided by the last one of the multiple multi-stage heat exchangers of the compressed air energy storage system.

[0008] In some embodiments, the first heat exchanger, the second heat exchanger, and the multi-stage heat exchanger are all shell and tube heat exchangers.

[0009] In some embodiments, the heat exchange medium stored in the heat storage tank is water.

[0010] In some embodiments, the number of the multi-stage heat exchangers is four.

[0011] In some embodiments, the compressed air energy storage system further includes a cold storage tank, and the outlet of the first heat exchanger is also connected to the cold storage tank.

[0012] The utility model provides a compressed air energy storage and cryogenic air separation heat coupling system, which couples the compressed air energy storage system with the cryogenic air separation purification system. The compression heat generated in the compressed air energy storage stage is mainly transferred to the cryogenic air separation purification system through hot water, and this part of hot water is used to heat the regenerated gas. The compression heat is fully utilized to avoid the energy waste caused by heating the regenerated gas by electric heating. In addition, a part of the compression heat is used to directly heat the regenerated gas, without converting the compression heat into electrical energy, and then converting the electrical energy into thermal energy, which effectively avoids the waste of energy conversion between different energy sources, thereby improving the comprehensive efficiency of compressed air energy storage. The cryogenic air separation purification system does not need to consider the heat source (electricity or steam) separately to complete the heating of the regenerated gas, and fully realizes energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the working process of the compressed air energy storage and deep cold air separation heat coupling system according to an embodiment of the utility model. DETAILED DESCRIPTION

[0014] See also Figure 1 As shown, according to an embodiment of the utility model, a compressed air energy storage and cryogenic air separation heat coupling system is provided, including a compressed air energy storage system and a cryogenic air separation purification system, wherein the cryogenic air separation purification system includes a first heat exchanger, and the compressed air energy storage system includes a heat storage tank, wherein the first outlet of the heat storage tank is connected in series with a plurality of multi-stage heat exchangers through a pipeline, wherein the second outlet of the heat storage tank is connected to the inlet of the first heat exchanger, and the outlet pipeline of the first heat exchanger is connected to the first outlet of the heat storage tank through a three-way valve, so that the heat exchange medium discharged from the first heat exchanger is mixed with the heat exchange medium discharged from the first outlet of the heat storage tank and then flows into the multi-stage heat exchanger. The compressed air energy storage system is coupled with the cryogenic air separation purification system. The compressed heat generated in the compressed air energy storage stage is mainly transferred to the cryogenic air separation purification system through hot water, and this part of hot water is used to heat the regenerated gas. The compressed heat is fully utilized to avoid the energy waste caused by heating the regenerated gas by using electric heating. In addition, a portion of the compression heat is used to directly heat the regenerated gas, without the need to convert the compression heat into electrical energy and then convert the electrical energy into thermal energy, which effectively avoids the waste of energy conversion between different energy sources and thereby improves the comprehensive efficiency of compressed air energy storage. The deep-cold air separation purification system does not need to consider the heat source (electricity or steam) separately to complete the heating of the regenerated gas, thus fully realizing energy savings.

[0015] Specifically, in the compressed air energy storage stage, the heat in the high-temperature and high-pressure compressed air is stored in the heat storage tank through heat exchange, and part of the hot water in the heat storage tank is drained to the deep cold air separation purification system to heat the regenerated gas. The hot water after heat exchange is mixed with another part in the heat storage tank and then enters the expansion power generation stage to heat the high-pressure and low-temperature compressed air to improve the power generation efficiency of the expander. Take the implementation of a certain factory as an example to illustrate, Figure 1 As shown, when the compressed air energy storage system is charged, the air compressor compresses the air to generate a large amount of compression heat which is stored in the heat storage device (hot water tank). When power generation is required, the hot water stream 1 is divided into two streams. One stream is sent to the multi-stage heat exchanger of the compressed air energy storage system through the hot water pump B (becomes the hot water stream 2) to preheat the released compressed air for expansion and work. The other stream leaves the compressed air energy storage system and enters the deep cold air separation purification system through the hot water pump A (becomes the hot water stream 3) to enter the first heat exchanger to heat the regenerated gas. After the hot water stream 3 and the regenerated gas are heat-exchanged, the temperature of the regenerated gas rises to 175°C, and the hot water stream 3 leaves the heat exchanger and becomes the hot water stream 4, leaves the deep cold air separation purification system and enters the compressed air energy storage system, merges with the hot water stream 2 to become the hot water stream 5, and is transported to the multi-stage heat exchanger to preheat the compressed air for expansion and work. The whole process reduces the process of converting thermal energy into electrical energy, and then converting electrical energy into thermal energy to heat the regenerated gas, reduces the loss caused by energy conversion, and improves energy utilization.

[0016] In a specific embodiment, the cryogenic air separation purification system further includes a second heat exchanger, the air inlet of the second heat exchanger is connected to the regeneration gas inlet, the exhaust port of the second heat exchanger is connected to the air inlet of the first heat exchanger, and the heat exchange medium of the second heat exchanger is provided by the last of the plurality of multi-stage heat exchangers of the compressed air system. After heating the gas of the final expander, the temperature of the heat exchange medium is still relatively high, generally around 85 degrees. Under normal circumstances, this part of the heat cannot be used and directly flows back into the cold storage tank, resulting in energy waste. After the improvement, the heat exchange medium after heating the gas of the final expander is transported to the cryogenic air separation purification system, the regeneration gas is preheated, the regeneration gas is heated to about 70 degrees, and after absorbing enough cold energy, it flows into the cold storage tank, so as to achieve the technical effect of effectively utilizing this part of the heat and improve the heat exchange efficiency of the regeneration gas. It also stores more cold energy for the expansion power generation process.

[0017] In a specific embodiment, the first heat exchanger, the second heat exchanger and the multi-stage heat exchanger are all shell and tube heat exchangers. The shell and tube heat exchanger has a simple structure and is easy to use. Preferably, the regeneration gas passes through the shell side of the heat exchanger, and the heat exchange medium passes through the tube side of the heat exchanger.

[0018] In a specific embodiment, the heat exchange medium stored in the heat storage tank is water. Since the cryogenic air separation purification system produces a large amount of oxygen, it has high safety requirements, so using water as the heat exchange medium can improve the safety performance of the overall system.

[0019] In a specific embodiment, the number of the multi-stage heat exchangers is four.

[0020] In a specific embodiment, the compressed air energy storage system also includes a cold storage tank, and the outlet of the first heat exchanger is also connected to the cold storage tank. Normally, compressed air energy storage is only started when electricity consumption is low, and compressed air energy release is only used during peak electricity consumption, so it is intermittent. The cryogenic air separation purification system operates 24 hours a day, that is, the cryogenic air separation purification system requires continuous heat energy to heat the regenerated gas. Therefore, a path is introduced into the first heat exchanger in the heat storage tank. After heat exchange, the heat exchange medium is introduced into the cold storage tank for storage, which can meet the 24-hour heat energy demand of the cryogenic air separation purification system.

[0021] The above is only a preferred embodiment of the utility model, and is not intended to limit the utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the utility model should be included in the protection scope of the utility model. The above is only a preferred implementation of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the utility model, and these improvements and variations should also be regarded as the protection scope of the utility model.

Claims

1. A compressed air energy storage and cryogenic air separation heat coupling system, characterized in that: It includes a cryogenic air separation purification system and a compressed air energy storage system, the cryogenic air separation purification system includes a first heat exchanger, the compressed air energy storage system includes a heat storage tank, the first outlet of the heat storage tank is connected in series with a plurality of multi-stage heat exchangers through a pipeline, the second outlet of the heat storage tank is connected to the inlet of the first heat exchanger, and the outlet pipeline of the first heat exchanger is connected to the first outlet of the heat storage tank through a three-way valve, so that the heat exchange medium discharged from the first heat exchanger is mixed with the heat exchange medium discharged from the first outlet of the heat storage tank and then flows into the multi-stage heat exchanger.

2. The compressed air energy storage and deep cold air separation heat coupling system according to claim 1 is characterized in that: The cryogenic air separation purification system may further include a second heat exchanger, wherein an air inlet of the second heat exchanger is connected to a regeneration gas inlet of the cryogenic air separation purification system, an exhaust port of the second heat exchanger is connected to an air inlet of the first heat exchanger, and a heat exchange medium of the second heat exchanger is provided by the last one of the multi-stage heat exchangers in the compressed air energy storage system.

3. The compressed air energy storage and deep cold air separation heat coupling system according to claim 2 is characterized in that: The first heat exchanger, the second heat exchanger and the multi-stage heat exchanger are all shell and tube heat exchangers.

4. The compressed air energy storage and deep cold air separation heat coupling system according to claim 1 is characterized in that: The heat exchange medium stored in the heat storage tank is water.

5. The compressed air energy storage and deep cold air separation heat coupling system according to claim 1 is characterized in that: There are four multi-stage heat exchangers.

6. The compressed air energy storage and deep cold air separation heat coupling system according to claim 1 is characterized in that: The compressed air energy storage system also includes a cold storage tank, and the outlet of the first heat exchanger is also connected to the cold storage tank.

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