Air energy storage system utilizing ethylene gasification heat

Abstract

The invention provides an air energy storage system utilizing ethylene gasification heat, which comprises an air compression subsystem, a liquid ethylene cold energy utilization subsystem and an air liquefaction subsystem, and is characterized in that the air compression subsystem extracts air from the outside and compresses the air to target pressure; the liquid ethylene cold energy utilization subsystem is used for cooling compressed air by utilizing cold energy generated by gasification of liquid ethylene so as to fill up a cold capacity gap of air liquefaction, the air liquefaction subsystem is used for liquefying and storing the cooled air, and the liquid ethylene cold energy utilization subsystem comprises an ethylene conveying pipeline; the liquid ethylene cold energy cold storage heat exchanger is communicated with the ethylene conveying pipeline, the compressed air cooling heat exchanger is used for cooling compressed air, and the cold storage working medium circulation loop is used for transmitting cold energy of the liquid ethylene cold energy cold storage heat exchanger to the compressed air cooling heat exchanger; recovery of ethylene regasification waste cold and the requirement of a liquid air energy storage system for the cooling capacity can be met at the same time, and the overall round-trip efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical fields of utilization of ethylene gasification heat and energy storage technology, and particularly relates to an air energy storage system using ethylene gasification heat. Background Art

[0002] In the context of the expanding demand for clean energy, renewable energy power generation technologies have developed rapidly. However, the unpredictability and volatility of renewable energy power can impact the power grid and threaten its stable operation.

[0003] Energy storage technology is the key to solving the problem of new energy power grid connection impact. Energy storage technology absorbs new energy power or low-cost grid power and releases power at an appropriate time, which can not only eliminate the volatility of new energy power but also achieve power peak shaving.

[0004] Existing energy storage technologies that can be connected to the grid on a large scale include compressed air energy storage and pumped hydro storage, etc. Compressed air energy storage realizes the storage / release of electrical energy through the compression / expansion process of air. Pumped hydro storage absorbs electrical energy through a pump to pump water to a high-level reservoir for storage and releases electrical energy by discharging water to drive a generator. However, both compressed air energy storage technology and pumped hydro storage technology are restricted by geographical conditions and have limited development: compressed air energy storage depends on large-capacity gas storage spaces, such as abandoned mine shafts, salt caverns, etc.; pumped hydro storage depends on the height difference between high and low terrains.

[0005] Liquid air energy storage technology is a new energy storage technology developed on the basis of compressed air energy storage technology. It stores electrical energy with liquid air as the medium, greatly reducing the demand for gas storage space and overcoming the limitation of geographical conditions. However, liquid air energy storage technology has a cold energy gap, resulting in a low air liquefaction rate and overall round-trip efficiency. External cold energy needs to be introduced to improve the liquefaction rate and thus enhance the overall round-trip efficiency.

[0006] The existing research on the coupling system of liquid air energy storage and external cold energy mainly focuses on introducing the regasification cold energy of liquefied natural gas, and there is less research on other external cold energies, for example, the regasification cold energy of liquid ethylene. Liquid ethylene is usually regasified by directly heating with low-temperature steam. In this process, the cold energy of liquid ethylene is not reasonably utilized, a large amount of cold energy is wasted, and at the same time, a large amount of steam heat is consumed, resulting in double losses of cold energy and heat energy. Summary of the Invention

[0007] The purpose of the present invention is to solve the technical problems in the prior art that liquid ethylene is usually regasified by directly heating with low-temperature steam. In this process, the cold energy of liquid ethylene is not reasonably utilized, a large amount of cold energy is wasted, and liquid air energy storage technology has a cold energy gap, resulting in a low air liquefaction rate and overall round-trip efficiency. External cold energy needs to be introduced to improve the liquefaction rate.

[0008] To solve the above technical problems, the present invention provides an air energy storage system using the gasification heat of ethylene, which includes: an air compression subsystem, a liquid ethylene cold energy utilization subsystem, and an air liquefaction subsystem. The air compression subsystem extracts air from the outside and compresses the air to a target pressure. The liquid ethylene cold energy utilization subsystem uses the cold energy of the gasification of liquid ethylene to cool the compressed air to fill the cold quantity gap of air liquefaction. The air liquefaction subsystem liquefies and stores the cooled air. Among them, the liquid ethylene cold energy utilization subsystem includes an ethylene delivery pipeline, a liquid ethylene cold energy storage heat exchanger connected to the ethylene delivery pipeline, a compressed air cooling heat exchanger for cooling the compressed air, and a cold storage working medium circulation loop for transferring the cold energy of the liquid ethylene cold energy storage heat exchanger to the compressed air cooling heat exchanger. The cold storage working medium circulation loop stores and utilizes the cold energy of ethylene.

[0009] Further, the liquid ethylene cold energy storage heat exchanger has a first heat exchange side and a second heat exchange side. The ethylene delivery pipeline is connected to the first heat exchange side pipeline. The compressed air cooling heat exchanger has a third heat exchange side and a fourth heat exchange side. The second heat exchange side and the third heat exchange side pipelines are connected. The second heat exchange side and the third heat exchange side form a cold storage working medium circulation loop. The output end of the air compression subsystem is connected to the input end of the fourth heat exchange side by pipeline. The output end of the fourth heat exchange side is connected to the air liquefaction subsystem by pipeline.

[0010] Further, the cold storage working medium circulation loop further includes a first low-temperature storage tank, a circulation pump, and a first high-temperature storage tank. The low-temperature cold storage working medium output from the second heat exchange side leads to the first low-temperature storage tank. The low-temperature cold storage working medium of the first low-temperature storage tank leads to the input end of the third heat exchange side. The high-temperature cold storage working medium after heat exchange output from the output end of the third heat exchange side leads to the first high-temperature storage tank. The high-temperature cold storage working medium of the first high-temperature storage tank leads to the input end of the second heat exchange side. The circulation pump is used to drive the cold storage working medium to circulate in the cold storage working medium circulation loop.

[0011] Further, it further includes an external heat source utilization subsystem. The input end of the external heat source utilization subsystem is connected to the output end of the air liquefaction subsystem by pipeline. The external heat source utilization subsystem uses the heat of the external heat source to heat the high-pressure low-temperature air from the air liquefaction subsystem to high-pressure high-temperature air.

[0012] Further, it further includes an air turbine. The input end of the air turbine is connected to the output end of the external heat source utilization subsystem by pipeline.

[0013] Further, the external heat source utilization subsystem includes an external heat source, a heat storage working medium circulation loop, and an engine. The heat storage working medium circulation loop stores and utilizes the heat of the external heat source. The heat absorption end of the engine is connected to the external heat source through the heat storage working medium circulation loop. The cold absorption end of the engine is connected to the output end of the air liquefaction subsystem.

[0014] Furthermore, the heat storage working medium circulation loop includes a second low-temperature storage tank, a second high-temperature storage tank, and a second circulation pump. The outlet of the external heat source is connected to the inlet pipeline of the second high-temperature storage tank. The outlet of the second high-temperature storage tank is connected to the inlet pipeline of the heat absorption end of the engine. The outlet of the engine is connected to the inlet pipeline of the second low-temperature storage tank. The outlet of the second low-temperature storage tank is connected to the inlet pipeline of the external heat source.

[0015] Furthermore, it further includes a heat exchange heater which has more than two heat exchange sides. The inlet of one heat exchange side of the heat exchange heater is connected to the outlet pipeline of the second high-temperature storage tank. The outlet of this heat exchange side opposite to the inlet is connected to the inlet pipeline of the heat absorption end of the engine. The inlet of the other heat exchange side of the heat exchange heater is connected to the outlet pipeline of the cold absorption end of the engine. The outlet of this heat exchange side opposite to the inlet is connected to the inlet pipeline of the air turbine.

[0016] Furthermore, the compressed air cooling heat exchanger further includes a fifth heat exchange side. The inlet of the fifth heat exchange side is connected to the air liquefaction subsystem pipeline. The reverse-flow cold air generated during the gas liquefaction process in the air liquefaction subsystem leads to the fifth heat exchange side.

[0017] Furthermore, it further includes a pre-compression air cooling heat exchanger which uses the cold energy of ethylene and the cold energy of the air liquefaction subsystem to cool the air before compression. The air cooling heat exchanger has a sixth heat exchange side, a seventh heat exchange side, and an eighth heat exchange side. The inlet of the sixth heat exchanger is connected to the outlet pipeline of the first low-temperature storage tank. The outlet of the sixth heat exchanger is connected to the inlet pipeline of the first high-temperature storage tank. The inlet of the seventh heat exchange side is in communication with the atmospheric environment. The outlet of the seventh heat exchange side is connected to the inlet pipeline of the air compression subsystem. The inlet of the eighth heat exchange side is connected to the outlet pipeline of the fifth heat exchange side. The outlet of the eighth heat exchange side is in communication with the atmospheric environment.

[0018] As can be seen from the above technical solutions, the beneficial effects of the present invention are as follows: It can simultaneously meet the recovery of the waste cold of ethylene regasification and the cold quantity demand of the liquid air energy storage system, and improve the overall round-trip efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the air energy storage system using the heat of ethylene gasification provided by this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments, all of which do not depart from the scope of the present invention, and the descriptions and illustrations therein are essentially for illustrative purposes and not for limiting the present invention.

[0021] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0022] In order to further illustrate the principle and structure of the present invention, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Please refer to Figure 1 , an air energy storage system using the gasification heat of ethylene provided in this embodiment, includes an air compression subsystem 100, a liquid ethylene cold energy utilization subsystem 200, an air liquefaction subsystem 300, an external heat source utilization subsystem 400, and an air expansion subsystem 500.

[0024] The air compression subsystem 100 includes an air compressor 3. The air compressor 3 is used to compress air to a target pressure. The inlet stream of the air compressor 3 is the normal-pressure cold air at the outlet of the seventh heat exchange side H7 of the liquid ethylene cold energy utilization subsystem 200, the outlet stream of the air compressor 3 is high-pressure near-ambient-temperature air, and the outlet of the air compressor 3 is connected to the inlet of the fourth heat exchange side H4 of the liquid ethylene cold energy utilization subsystem 200.

[0025] The liquid ethylene cold energy utilization subsystem 200 includes a liquid ethylene cold energy storage heat exchanger 6, a compressed air cooling heat exchanger 4, an ethylene low-grade cold energy absorption heat exchanger 7, a pre-compression air cooling heat exchanger 2, a cold user 13, low-temperature liquid ethylene 5, intermediate-cooled ethylene, normal-temperature gaseous ethylene 8, a first low-temperature storage tank 9, a first high-temperature storage tank 11, a first circulation pump 10, a cold delivery working medium 12, normal-temperature and normal-pressure air, normal-pressure cold air, high-pressure near-ambient-temperature air, high-pressure cold air, reflux cold air, reflux intermediate-cooled cold air, and reflux normal-temperature air 14.

[0026] The described liquid ethylene cold energy storage heat exchanger 6 includes a first heat exchange side H1 and a second heat exchange side H2. The inlet stream of the first heat exchange side H1 of the liquid ethylene cold energy storage heat exchanger 6 is the low-temperature liquid ethylene 5 that needs to be vaporized during the all-weather period. The outlet stream of the first heat exchange side H1 is the medium-cooled ethylene, and the outlet of the first heat exchange side H1 is connected to the inlet of the ninth heat exchange side H9 of the ethylene low-grade cold energy absorption heat exchanger 7. The inlet of the second heat exchange side H2 is connected to the outlet of the first high-temperature storage tank 11. The inlet stream of the second heat exchange side H2 is the high-temperature cold energy storage working medium. The outlet stream of the second heat exchange side H2 is the low-temperature cold energy storage working medium, and the outlet of the second heat exchange side H2 is connected to the inlet of the first low-temperature storage tank 9. The outlet of the first low-temperature storage tank 9 is connected to the inlet of the first circulation pump 10. The outlet stream of the first circulation pump 10 is divided into multiple strands. One of them is connected to the inlet of the third heat exchange side H3 of the compressed air cooling heat exchanger 4, and the remaining strands are connected to the inlet of the sixth heat exchange side H6 of the pre-compression air cooler. The compressed air cooling heat exchanger 4 includes a third heat exchange side H3, a fifth heat exchange side H5, and a fourth heat exchange side H4. The inlet stream of the third heat exchange side H3 is the low-temperature cold energy storage working medium. The outlet stream of the third heat exchange side H3 is the high-temperature cold energy storage working medium, and the outlet of the third heat exchange side H3 is connected to the inlet of the first high-temperature storage tank 11. The inlet of the fifth heat exchange side H5 is connected to the outlet of the twelfth heat exchange side H12 of the air liquefaction subsystem 300. The inlet stream of the fifth heat exchange side H5 is the reverse-flow cold air from the outlet of the twelfth heat exchange side H12 of the air liquefaction subsystem 300. The outlet of the fifth heat exchange side H5 is the reverse-flow medium-cooled cold air, and the outlet of the fifth heat exchange side H5 is connected to the inlet of the eighth heat exchange side H8 of the pre-compression air cooling heat exchanger 2. The inlet of the fourth heat exchange side H4 is connected to the outlet of the air compressor 3 of the air compression subsystem 100. The inlet stream of the fourth heat exchange side H4 is the high-pressure near-ambient temperature air. The outlet stream of the fourth heat exchange side H4 is the high-pressure cold air, and the outlet of the fourth heat exchange side H4 is connected to the inlet of the eleventh heat exchange side H11 of the air liquefaction subsystem 300. The pre-compression air cooling heat exchanger 2 includes a sixth heat exchange side H6, an eighth heat exchange side H8, and a seventh heat exchange side H7. The inlet of the sixth heat exchange side H6 is connected to the remaining strands of the divided outlet of the first circulation pump 10. The inlet stream of the sixth heat exchange side H6 is the low-temperature cold energy storage working medium. The outlet stream of the sixth heat exchange side H6 is the high-temperature cold energy storage working medium, and the outlet of the sixth heat exchange side H6 is connected to the inlet of the first high-temperature storage tank 11.The inlet of the eighth heat exchange side H8 is connected to the outlet of the fifth heat exchange side H5 of the compressed air cooling heat exchanger 4. The flow stream at the inlet of the eighth heat exchange side H8 is the cold air in the reverse flow. The flow stream at the outlet of the eighth heat exchange side H8 is the normal temperature air 14 in the reverse flow. The eighth heat exchange side H8 leads to the atmospheric environment. The inlet of the seventh heat exchange side H7 is connected to the atmospheric environment. The flow stream at the inlet of the seventh heat exchange side H7 is the normal temperature and normal pressure air. The flow stream at the outlet of the seventh heat exchange side H7 is the normal pressure cold air. The outlet of the seventh heat exchange side H7 is connected to the inlet of the air compressor 3.

[0027] The ethylene low-grade cold energy absorption heat exchanger 7 includes a ninth heat exchange side H9 and a tenth heat exchange side H10. The ninth heat exchange side H9 is the heat absorption side of the medium-cooled ethylene. The tenth heat exchange side H10 is the heat release side of the cold delivery working medium 12. The inlet of the ninth heat exchange side H9 is connected to the outlet of the first heat exchange side H1. The flow stream at the inlet of the ninth heat exchange side H9 is the medium-cooled ethylene. The outlet of the ninth heat exchange side H9 is the normal temperature gaseous ethylene 8. The outlet of the ninth heat exchange side H9 leads to the downstream gaseous ethylene user. The outlet of the tenth heat exchange side H10 is connected to the inlet of the cold user 13. The inlet of the tenth heat exchange side H10 is connected to the outlet of the cold user 13.

[0028] The described air liquefaction subsystem 300 includes a cold storage / cold release heat exchanger 15, a cryogenic turbine 16, a gas-liquid separator 17, a cryogenic liquid air storage tank 18, and a cryogenic pump 19. The cold storage / cold release heat exchanger 15 includes an eleventh heat exchange side H11, a twelfth heat exchange side H12, and a thirteenth heat exchange side H13. The inlet of the eleventh heat exchange side H11 is connected to the outlet of the fourth heat exchange side H4. The inlet stream of the eleventh heat exchange side H11 is high-pressure cold air, and the outlet stream of the eleventh heat exchange side H11 is high-pressure low-temperature air. The outlet of the eleventh heat exchange side H11 is connected to the inlet of the cryogenic turbine 16. The outlet of the cryogenic turbine 16 is connected to the inlet of the gas-liquid separator 17. The gas-phase outlet of the gas-liquid separator 17 is reverse-flow low-temperature air, and the gas-phase outlet of the gas-liquid separator 17 is connected to the inlet of the twelfth heat exchange side H12. The liquid-phase outlet of the gas-liquid separator 17 is cryogenic liquid air, and the liquid-phase outlet of the gas-liquid separator 17 is connected to the inlet of the cryogenic liquid air storage tank 18. The inlet of the twelfth heat exchange side H12 is connected to the gas-phase outlet of the gas-liquid separator 17. The inlet stream of the twelfth heat exchange side H12 is reverse-flow low-temperature air, and the outlet stream of the twelfth heat exchange side H12 is reverse-flow cold air. The outlet of the twelfth heat exchange side H12 is connected to the inlet of the fifth heat exchange side H5. The outlet stream of the cryogenic liquid air storage tank 18 is cryogenic liquid air, and the outlet of the cryogenic liquid air storage tank 18 is connected to the inlet of the cryogenic pump 19. The outlet stream of the cryogenic pump 19 is cryogenic high-pressure liquid air, and the outlet of the cryogenic pump 19 is connected to the inlet of the thirteenth heat exchange side H13. The inlet stream of the thirteenth heat exchange side H13 is cryogenic high-pressure liquid air, and the outlet stream of the thirteenth heat exchange side H13 is gaseous high-pressure cold air. The outlet of the thirteenth heat exchange side H13 is connected to the inlet of the fourteenth heat exchange side H14 of the engine 20 in the external heat source utilization subsystem 400.

[0029] The described external heat source utilization subsystem 400 includes an external heat source 23, a second low-temperature storage tank 21, a second high-temperature storage tank 24, a second circulation pump 22, a heat exchange heater 25, and an engine 20.

[0030] The inlet of the external heat source 23 is connected to the outlet of the second circulation pump 22, and the outlet of the external heat source 23 is connected to the inlet of the second high-temperature storage tank 24. The outlet of the second high-temperature storage tank 24 is connected to the inlet of the seventeenth heat exchange side H17 of the heat exchange heater 25. The outlet of the seventeenth heat exchange side H17 of the heat exchange heater 25 is connected to the inlet of the fifteenth heat exchange side H15 of the engine 20. The outlet of the fifteenth heat exchange side H15 of the engine 20 is connected to the inlet of the second low-temperature storage tank 21. The outlet of the second low-temperature storage tank 21 is connected to the inlet of the second circulation pump 22. The inlet of the fourteenth heat exchange side H14 of the engine 20 is connected to the outlet of the thirteenth heat exchange side H13 of the air liquefaction subsystem 300. The outlet of the fourteenth heat exchange side H14 of the engine 20 is connected to the inlet of the sixteenth heat exchange side H16 of the heat exchange heater 25. The outlet of the sixteenth heat exchange side H16 of the heat exchange heater 25 is connected to the inlet of the air turbine 26 of the air expansion subsystem 500.

[0031] The second low-temperature storage tank 21 and the second high-temperature storage tank 24 are used to store the heat storage working medium before and after absorbing heat from the external heat source 23, and the second circulation pump 22 provides the circulation power for the circulation process of the heat storage working medium. The external heat source 23 is used to provide heat to heat the circulating heat storage working medium. The inlet stream of the external heat source 23 is the low-temperature heat storage working medium, and the outlet stream of the external heat source 23 is the high-temperature heat storage working medium. The heat exchange heater 25 includes a sixteenth heat exchange side H16 and a seventeenth heat exchange side H17. The seventeenth heat exchange side H17 is the heat release side of the high-temperature heat storage working medium. The inlet stream of the seventeenth heat exchange side H17 is the high-temperature heat storage working medium, and the outlet stream of the seventeenth heat exchange side H17 is the medium-temperature heat storage working medium. The sixteenth heat exchange side H16 is the heat absorption side before air expansion. The inlet stream of the sixteenth heat exchange side H16 is the medium-temperature high-pressure air, and the outlet stream of the sixteenth heat exchange side H16 is the high-temperature high-pressure air. The engine 20 includes fourteenth and fifteenth heat exchange sides H15. The fifteenth heat exchange side H15 is the heat release side of the medium-temperature heat storage working medium. The inlet of the fifteenth heat exchange side H15 is the medium-temperature heat storage working medium, and the outlet of the fifteenth heat exchange side H15 is the low-temperature heat storage working medium. The fourteenth heat exchange side H14 is the heat absorption side of the vaporized high-pressure cold air. The inlet of the fourteenth heat exchange side H14 is the vaporized high-pressure cold air, and the outlet of the fourteenth heat exchange side H14 is the medium-temperature high-pressure air. The engine 20 performs work driven by the heat flow on the fifteenth heat exchange side H15 and the fourteenth heat exchange side H14.

[0032] The described air expansion subsystem 500 includes an air turbine 26. The inlet of the air turbine 26 is connected to the outlet of the sixteenth heat exchange side H16 of the external heat source utilization subsystem 400. The inlet stream of the air turbine 26 is gaseous high-pressure and high-temperature air, the outlet stream of the air turbine 26 is gaseous normal-pressure and medium-temperature air, and the outlet of the air turbine 26 is ambient air.

[0033] Optionally, the engine 20 described above can be various types of engines such as a Stirling engine, a steam engine, a thermoacoustic engine, an external combustion turbine, a compression-ignition external combustion engine, a spark-ignition external combustion engine, etc., as well as various power cycles such as an organic Rankine cycle, a steam Rankine cycle, a Kalina cycle, a Brayton cycle, etc.

[0034] Optionally, the air compressor 3 described above can be of piston type, screw type, centrifugal type, axial flow type, swash plate type, scroll type and other compressor structures. The compressor can include one or more units, and multiple compressors can be connected in series, in parallel or in a combined manner to form a corresponding compressor unit.

[0035] Optionally, the air turbine 26 described above can be of piston type, screw type, centrifugal type, axial flow type, diagonal flow type, scroll type and other turbine structures. The turbine can include one or more units, and multiple turbines can be connected in series, in parallel or in a combined manner to form a corresponding turbine unit.

[0036] Optionally, the heat storage method of the heat of the external heat source 23 described above can be heat storage by thermal oil circulation, heat storage by molten salt circulation, or heat storage by water circulation, etc., and can also be replaced by a solid-phase packed bed type heat storage device or a solid-phase moving packed bed type heat storage, as well as various combinations of one or more of them.

[0037] Optionally, the various heat exchangers described above can be tubular heat exchangers, plate heat exchangers, direct contact heat exchangers, regenerative heat exchangers. The heat exchange methods of the various heat exchangers are not limited. Whether it is a countercurrent arrangement, a cocurrent arrangement or other arrangement methods, they are all within the protection scope of the present invention.

[0038] Optionally, the cold storage methods in the liquid ethylene cold energy utilization subsystem 200 and the air liquefaction subsystem 300 described above are not limited. It can not only use organic, inorganic or mixed liquid-phase working media such as methanol, methanol aqueous solution with any concentration, R600, R160, R290, R11, R123, R610, R601, ethanol, ethanol aqueous solution with any concentration, isopropane, acetone, etc. for cold storage, or organic, inorganic or mixed solid-phase working media such as metal, rock, glass, solid polymer, solid compound, etc. for cold storage, or various phase change materials for cold storage, and combinations of one or more of them.

[0039] Optionally, the above-described liquid ethylene cold energy utilization subsystem 200 can be replaced with a form in which liquid ethylene directly exchanges heat with air without using a cold storage medium, or a form in which a cold storage medium or liquid ethylene directly exchanges heat with air in different time periods.

[0040] Optionally, the number of split streams of the outlet stream of the first circulation pump 10 described above matches the number of stages of the air compressor 3 and the number of air coolers, but the distribution ratio is not limited and can be various distribution methods such as equal enthalpy rise distribution, equal mass flow distribution, equal temperature rise distribution, equal cooling temperature, etc.

[0041] Optionally, the type of the above-described low-temperature turbine 16 is not limited and can be a turbine with a liquid expander or a pure liquid expander, or other throttling elements such as various throttle valves.

[0042] Optionally, the type of the above-described gas-liquid separator 17 is not limited and can be microporous filtration separation, wire mesh separation, packing separation, centrifugal separation, baffle separation (baffle separation), or gravity sedimentation separation.

[0043] Optionally, the type of the above-described low-temperature liquid air storage tank 18 is not limited and can be a Dewar tank, a low-temperature storage tank, a single-containment tank, a double-containment tank, a full-containment tank, or a membrane tank, etc.

[0044] Optionally, the flow arrangement mode of the above-described high-temperature heat storage working medium exchanging heat with the heat exchange heater 25 and the heating heat exchange side of the engine 20 is not limited. It can not only be that the same stream flows through the heat exchange heater 25 and the heating heat exchange side of the engine 20 in sequence, but also can be replaced by the stream being split and then flowing through the heat exchange heater 25 and the heating heat exchange side of the engine 20 respectively and then re-converging, or a combined flow arrangement mode based on the above methods.

[0045] Optionally, the types of the above-described second low-temperature storage tank 21, second high-temperature storage tank 24, first low-temperature storage tank 99, and first high-temperature storage tank 11 are not limited and can be various types such as vertical storage tanks, horizontal storage tanks, and trough storage tanks. The storage tanks can be one or a combination of multiple connected tanks.

[0046] Optionally, the above-described external heat source 23 can be replaced by waste heat or surplus heat in industrial processes such as cement, steel, thermoelectricity, and ceramics, geothermal heat energy, biomass energy, solar energy, and heat sources such as fossil fuel combustion, as well as a combination of one or more of them.

[0047] Optionally, the types of the cryogenic pump 19, the first circulation pump 10, and the second circulation pump 22 described above are not limited and can be reciprocating, rotary, centrifugal, mixed-flow, axial-flow, vortex, etc. The cryogenic pump 19, the first circulation pump 10, and the second circulation pump 22 can be connected in series, parallel, or in a combined manner with one or more units.

[0048] Optionally, the cold-carrying working fluid 12 described above is not limited and can be gaseous working fluids such as pressurized air and nitrogen, or liquid working fluids such as methanol aqueous solutions with any concentration, and combinations of one or more of them.

[0049] Optionally, the cold user 13 described above is not limited and can be various cold users 13 such as fresh food cold storages, database cooling, and industrial cooling.

[0050] The process flow of an air energy storage system using the gasification heat of ethylene provided by the present invention is as follows:

[0051] At the start of the energy storage stage (low electricity consumption period), the feed air 1 at normal temperature and pressure is cooled to normal pressure cold air by the pre-compression air cooling heat exchanger 2 and then compressed to a high-pressure near-normal temperature state by the air compressor 3 while absorbing electrical energy. Subsequently, the high-pressure near-normal temperature air absorbs the cold energy of the cold storage working fluid from the first low-temperature storage tank 9 and the reflux cold air from the cold storage / cold release heat exchanger 15 in the compressed air cooling heat exchanger 4, and is further cooled to a low temperature state by absorbing the cold energy of the cold storage medium in the cold storage / cold release heat exchanger 15 and the reflux low-temperature air from the gas-liquid separator 17. Then, the high-pressure low-temperature air is cooled and depressurized to a low-temperature near-atmospheric pressure gas-liquid two-phase state by the low-temperature turbine 16 and separated into gas and liquid by the gas-liquid separator 17. Among them, the low-temperature gaseous air refluxes successively through the cold storage / cold release heat exchanger 15, the post-compression air cooling heat exchanger 4, and the pre-compression air cooling heat exchanger 2 to release cold energy. The low-temperature liquid air is stored in the low-temperature liquid air storage tank 18, marking the end of the energy storage stage.

[0052] At the beginning of the energy release stage (peak power consumption period), the low-temperature and normal-pressure liquid air is pressurized by the cryogenic pump 19 and sent to the cold storage / cold release heat exchanger 15 to release cold energy and gasify. Among them, the cold energy is absorbed and stored by the cold storage medium in the cold storage / cold release heat exchanger. After releasing the cold energy, the high-pressure gaseous cold air sequentially passes through the fourteenth heat exchange side H14 of the engine 20 and the sixteenth heat exchange side H16 of the heat exchange heater 25, absorbing heat to rise to a high-temperature and high-pressure state. Among them, the heat of the heat exchange heater 25 directly comes from the heat release of the high-temperature heat storage working medium in the second high-temperature storage tank 24, and the heat release of the engine 20 is the heat release during the cycle process of the engine 20 driven by the heat release of the heat storage working medium. The high-temperature and high-pressure air after absorbing heat drives the air turbine 26 to do work and generate electric energy, and the air turbine exhausts 27 to the atmosphere. The heat of the heat storage working medium comes from the external heat source 23: the low-temperature heat storage working medium from the second low-temperature storage tank 21 absorbs heat and increases in temperature under the driving force of the second circulation pump 22 through the external heat source 23. Then, the high-temperature heat storage working medium flows into the second high-temperature storage tank 24 and waits to release heat after the start of the energy release stage process, flowing through the heat exchange heater 25 and the engine 20 to release heat.

[0053] For the low-temperature liquid ethylene 5, the low-temperature liquid ethylene 5 releases high-grade cold energy through the liquid ethylene cold energy cold storage heat exchanger 6, and this part of the high-grade cold energy is absorbed by the heat storage working medium from the first high-temperature storage tank 11 and stored in the first low-temperature storage tank 9. Part of the low-temperature heat storage working medium stored in the first low-temperature storage tank 9 and the reflux cold air from the cold storage / cold release heat exchanger 15 together release cold energy to cool the nearly normal-temperature and high-pressure air from the air compressor 3. After releasing the cold energy, the heat storage working medium returns to the first high-temperature storage tank 11. The reflux medium cold air that has released part of the cold energy and the remaining part of the low-temperature heat storage working medium from the first low-temperature storage tank 9 together cool the feed air 1 at normal temperature and pressure in the pre-compression air cooler 2. After releasing the cold energy, the heat storage working medium returns to the first high-temperature storage tank 11, and the reflux medium cold air is directly discharged into the atmospheric environment after warming up to normal temperature. The intermediate-cooled ethylene that has released all the high-grade cold energy in the liquid ethylene cold energy cold storage heat exchanger 6 releases low-grade cold energy through the ethylene low-grade cold energy absorption heat exchanger 7 to rise to normal-temperature gaseous ethylene 8. This part of the low-grade cold energy of the ethylene is absorbed by the cold delivery working medium 12 and sent to the cold user 13.

[0054] An air energy storage system using the gasification heat of ethylene provided by the present invention cools air by introducing the regasification waste cold of liquid ethylene, makes up for the cold energy gap of the traditional liquid air energy storage system, obtains a higher air liquefaction rate, and reduces the compression power consumption through pre-compression cooling.

[0055] An air energy storage system utilizing the gasification heat of ethylene provided by the present invention introduces the heat of an external heat source 23 to provide the heat required for air reheating and heating, and drives the engine to do work to increase the power generation, which can improve the overall efficiency of the system and obtain good economy and thermodynamic performance.

[0056] An air energy storage system utilizing the gasification heat of ethylene provided by the present invention stores the regasification cold energy of ethylene through an intermediate cold energy storage medium, realizing the high-efficiency and high-value utilization of the cold energy of ethylene, ensuring the uninterrupted gasification process of ethylene and avoiding the combustion and explosion safety risks of direct heat exchange between ethylene and air.

[0057] An air energy storage system utilizing the gasification heat of ethylene provided by the present invention applies the regasification waste cold of liquid ethylene to cool the air before and after compression, reducing the compression process temperature and the air compression power consumption, and improving the system efficiency.

[0058] An air energy storage system utilizing the gasification heat of ethylene provided by the present invention adds an engine 20 to do work with the heat of an external heat source 23 as the heat source, increasing the power generation and efficiency of the system.

[0059] An air energy storage system utilizing the gasification heat of ethylene provided by the present invention uses the heat released by the engine 20 to preheat the gaseous cold air. It not only uses the cold energy of the gaseous cold air to provide a cold source with a lower temperature for the engine 20, improving the efficiency of the engine 20, but also reasonably utilizes the heat released by the engine 20.

[0060] In summary, an air energy storage system utilizing the gasification heat of ethylene provided by the present invention can simultaneously meet the recovery of the regasification waste cold of ethylene, the cold energy demand of the liquid air energy storage system, and flexibly introduce the heat of an external heat source 23 to improve the system efficiency.

[0061] Although the present invention has been described with reference to several exemplary embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but should be broadly construed within the spirit and scope defined by the appended claims. Therefore, all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. An air energy storage system utilizing the gasification heat of ethylene, characterized in that, It includes an air compression subsystem, a liquid ethylene cold energy utilization subsystem, and an air liquefaction subsystem. The air compression subsystem extracts air from the outside and compresses the air to the target pressure. The liquid ethylene cold energy utilization subsystem utilizes the cold energy of the vaporization of liquid ethylene to cool the compressed air to fill the cold energy gap for air liquefaction. The air liquefaction subsystem liquefies and stores the cooled air. Among them, the liquid ethylene cold energy utilization subsystem includes an ethylene delivery pipeline, a liquid ethylene cold energy storage heat exchanger connected to the ethylene delivery pipeline, a compressed air cooling heat exchanger for cooling the compressed air, and a cold energy storage working fluid circulation loop for transferring the cold energy of the liquid ethylene cold energy storage heat exchanger to the compressed air cooling heat exchanger. The cold energy storage working fluid circulation loop stores and utilizes the cold energy of ethylene.

2. The air energy storage system using the gasification heat of ethylene according to claim 1, characterized in that, The liquid ethylene cold energy storage heat exchanger has a first heat exchange side and a second heat exchange side. The ethylene delivery pipeline is connected to the pipeline of the first heat exchange side. The compressed air cooling heat exchanger has a third heat exchange side and a fourth heat exchange side. The pipeline of the second heat exchange side and the third heat exchange side are connected. The second heat exchange side and the third heat exchange side form the cold energy storage working fluid circulation loop. The output end of the air compression subsystem is connected to the input end pipeline of the fourth heat exchange side. The output end of the fourth heat exchange side is connected to the air liquefaction subsystem pipeline.

3. The air energy storage system using the gasification heat of ethylene according to claim 2, characterized in that, The cold energy storage working fluid circulation loop further includes a first low-temperature storage tank, a circulation pump, and a first high-temperature storage tank. The low-temperature cold energy storage working fluid output from the second heat exchange side leads to the first low-temperature storage tank. The low-temperature cold energy storage working fluid in the first low-temperature storage tank leads to the input end of the third heat exchange side. The high-temperature cold energy storage working fluid after heat exchange output from the output end of the third heat exchange side leads to the first high-temperature storage tank. The high-temperature cold energy storage working fluid in the first high-temperature storage tank leads to the input end of the second heat exchange side. The circulation pump is used to drive the cold energy storage working fluid to circulate in the cold energy storage working fluid circulation loop.

4. The air energy storage system using the gasification heat of ethylene according to claim 1, wherein It further includes an external heat source utilization subsystem. The input end of the external heat source utilization subsystem is connected to the output end pipeline of the air liquefaction subsystem. The external heat source utilization subsystem utilizes the heat of the external heat source to heat the high-pressure low-temperature air from the air liquefaction subsystem to high-pressure high-temperature air.

5. The air energy storage system using the gasification heat of ethylene according to claim 4, characterized in that, It further includes an air turbine. The input end of the air turbine is connected to the output end pipeline of the external heat source utilization subsystem.

6. The air energy storage system using the gasification heat of ethylene according to claim 5, characterized in that, The external heat source utilization subsystem includes an external heat source, a heat storage working fluid circulation loop, and an engine. The heat storage working fluid circulation loop stores and utilizes the heat of the external heat source. The heat absorption end of the engine is connected to the external heat source through the heat storage working fluid circulation loop. The cold absorption end of the engine is connected to the output end of the air liquefaction subsystem.

7. The air energy storage system using the gasification heat of ethylene according to claim 6, characterized in that, The heat storage working fluid circulation loop includes a second low-temperature storage tank, a second high-temperature storage tank, and a second circulation pump. The outlet of the external heat source is connected to the inlet pipeline of the second high-temperature storage tank. The outlet of the second high-temperature storage tank is connected to the input port of the heat absorption end of the engine. The outlet of the engine is connected to the inlet pipeline of the second low-temperature storage tank. The outlet of the second low-temperature storage tank is connected to the inlet pipeline of the external heat source.

8. The air energy storage system using the gasification heat of ethylene according to claim 7, characterized in that, It further includes a heat exchange heater which has more than two heat exchange sides. The inlet of one heat exchange side of the heat exchange heater is connected to the outlet pipeline of the second high-temperature storage tank, and the outlet of this heat exchange side opposite to the inlet is connected to the inlet pipeline of the heat absorption end of the engine; the inlet of the other heat exchange side of the heat exchange heater is connected to the outlet pipeline of the cold absorption end of the engine, and the outlet of this heat exchange side opposite to the inlet is connected to the inlet pipeline of the air turbine.

9. The air energy storage system using the gasification heat of ethylene according to claim 3, characterized in that, The compressed air cooling heat exchanger further includes a fifth heat exchange side. The inlet of the fifth heat exchange side is connected to the air liquefaction subsystem pipeline, and the reverse-flow cold air generated during the gas liquefaction process in the air liquefaction subsystem leads to the fifth heat exchange side.

10. The air energy storage system utilizing the gasification heat of ethylene according to claim 9, characterized in that, It further includes a pre-compression air cooling heat exchanger which uses the cold energy of ethylene and the cold energy of the air liquefaction subsystem to cool the air before compression. The air cooling heat exchanger has a sixth heat exchange side, a seventh heat exchange side and an eighth heat exchange side. The inlet of the sixth heat exchanger is connected to the outlet pipeline of the first low-temperature storage tank, and the outlet of the sixth heat exchanger is connected to the inlet pipeline of the first high-temperature storage tank. The inlet of the seventh heat exchange side is in communication with the atmospheric environment, and the outlet of the seventh heat exchange side is connected to the inlet pipeline of the air compression subsystem. The inlet of the eighth heat exchange side is connected to the outlet pipeline of the fifth heat exchange side, and the outlet of the eighth heat exchange side is in communication with the atmospheric environment.

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