Liquefied air energy storage system based on single-tower dehydration and decarbonization

Abstract

The liquefied air energy storage system comprises a molecular sieve water separator and a molecular sieve adsorption tower, an air output pipe of the separator is connected with a top gas connecting pipe of the molecular sieve adsorption tower, and a bottom gas connecting pipe of the molecular sieve adsorption tower is connected with a cold box front compressor unit. The cold box front compressor unit is communicated with an air pipeline in the cold box, and an outlet of the air pipeline in the cold box is communicated with a first liquefied air storage tank through a first liquefied air output pipe with a first throttling valve; the output end of a liquid air pressure pump on a first liquefied air storage tank output pipe of the first liquefied air storage tank is communicated with the air input end of the expansion unit, the air output end of the expansion unit is provided with a hot blowing conveying pipe and a cold blowing conveying pipe, and the hot blowing conveying pipe is communicated with a bottom gas connecting pipe through a first heater and an electric heater; and the output end of the cold blowing gas conveying pipe is connected to the output end of the electric heater output pipe. The invention has the advantages of low equipment cost and low energy consumption.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a liquefied air energy storage system. Background Art

[0002] Liquefied air energy storage technology usually refers to using electricity to compress air and then deep-cool and liquefy it for storage in tanks during periods of low electricity prices; during periods of peak electricity prices, the liquefied air is pressurized and expanded to gasify it, driving gas turbines and generators to generate electricity.

[0003] The current liquefied air energy storage system has some drawbacks: the two-tower and three-tower molecular sieve dehydration and decarbonization processes require additional energy consumption to pressurize the regenerated gas, which leads to high cost of liquefied air energy storage technology and poor process continuity. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to provide a liquefied air energy storage system based on single-tower dehydration and decarbonization, which only has a single molecular sieve adsorption tower, has a simple structure, low cost, low energy consumption, can store energy during the trough period of electricity prices at night, and release energy during the peak period of electricity prices during the day, has high energy storage density and large energy storage capacity.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is: a liquefied air energy storage system based on single-tower dehydration and decarbonization, comprising: a molecular sieve water separator for removing free water in the air and a molecular sieve adsorption tower for removing carbon dioxide and moisture in the air, the filler in the molecular sieve adsorption tower comprises a 13X type molecular sieve layer and an activated alumina desiccant layer arranged in sequence from bottom to top; the molecular sieve water separator is connected to a separator air input pipe, a separator air output pipe and a separator drain pipe, the separator air input pipe is connected to a compressor unit, and the air pressure delivered to the separator air input pipe after being compressed and cooled by the compressor unit is controlled at 1.0~4.0MPa, temperature is 30℃~35℃, the separator air output pipe is connected to the top gas pipe of the molecular sieve adsorption tower, the bottom gas pipe of the molecular sieve adsorption tower is connected to the air input end of the cold box front compressor unit, the bottom gas pipe is provided with a bottom gas pipe control valve, the air output end of the cold box front compressor unit is communicated with the inlet of the air pipeline in the cold box, the outlet of the air pipeline in the cold box is connected to the first liquefied air output pipe with a first throttle valve, the first liquefied air output pipe is connected to the first liquefied air storage tank, the pressure of the liquid air in the first liquefied air storage tank is 1.9MPa~2.0MP a, the temperature is -156°C; a liquid air booster pump is arranged on the output pipe of the first liquefied air storage tank of the first liquefied air storage tank, and the liquid air booster pump pressurizes the liquid air to 10.0MPa~12.0MPa, and the output end of the liquid air booster pump is connected to the air input end of the expansion unit, and the air output end of the expansion unit is provided with a hot blowing air delivery pipe with a hot blowing air output control valve, a cold blowing air delivery pipe with a cold blowing air output control valve and an expander discharge pipe, the hot blowing air delivery pipe is connected to the first heater heated medium inlet of the first heater, the first heater heated medium outlet is connected to the inlet of the electric heater, and the electric heater An electric heater output pipe is arranged at the outlet, which is connected to the bottom gas connecting pipe between the molecular sieve adsorption tower and the bottom gas connecting pipe control valve, a first check valve and a first back-blowing control valve are arranged at the output end of the electric heater output pipe, and the air temperature output by the electric heater output pipe is controlled at 195°C-200°C; the output end of the cold blowing air delivery pipe is connected to the output end of the electric heater output pipe, and a second check valve is arranged at the output end of the cold blowing air delivery pipe; a molecular sieve adsorption tower regeneration gas output pipe is connected to the top gas connecting pipe of the molecular sieve adsorption tower, and a molecular sieve adsorption tower regeneration gas output control valve is arranged on the molecular sieve adsorption tower regeneration gas output pipe.

[0006] Furthermore, in the aforementioned liquefied air energy storage system based on single-tower dehydration and decarbonization, a 10 cm thick porcelain ball layer is provided at the bottom of the 13X molecular sieve layer, a 5-8 cm porcelain ball layer is laid between the 13X molecular sieve layer and the activated alumina desiccant layer for separation, and a stainless steel wire mesh is provided on the top of the activated alumina desiccant layer.

[0007] Furthermore, in the aforementioned liquefied air energy storage system based on single-tower dehydration and decarbonization, a second air pipeline is also provided in the cold box, the air output end of the cold box front compressor unit is also connected to the inlet of the second air pipeline in the cold box, the outlet of the second air pipeline is connected to a second liquefied air output pipe with a second throttle valve, and the second liquefied air output pipe is connected to the second liquefied air storage tank; a cooling medium liquid-to-air pipeline is provided in the cold box, and the second liquefied air storage tank output pipe on the second liquefied air storage tank is connected to the inlet of the cooling medium liquid-to-air pipeline in the cold box; a low-temperature air pipeline is also provided in the cold box, and the second liquefied air storage tank low-temperature air output pipe on the top of the second liquefied air storage tank is connected to the inlet of the low-temperature air pipeline in the cold box, and the outlet of the cooling medium liquid-to-air pipeline and the outlet of the low-temperature air pipeline are both connected to the air input end of the cold box front compressor unit.

[0008] Furthermore, in the aforementioned liquefied air energy storage system based on single-tower dehydration and decarbonization, an LNG pipeline is arranged in the cold box, the inlet of the LNG pipeline is connected to the liquefied natural gas input pipe, and the outlet of the LNG pipeline is connected to the liquefied natural gas output pipe.

[0009] Furthermore, in the aforementioned liquefied air energy storage system based on single-tower dehydration and decarbonization, a low-temperature nitrogen pipeline is arranged in the cold box, the inlet of the low-temperature nitrogen pipeline is connected to a nitrogen input pipe, the nitrogen input pipe is connected to a nitrogen cold storage bed, the temperature of the low-temperature nitrogen in the nitrogen cold storage bed is maintained at -140°C to -142°C, the outlet of the low-temperature nitrogen pipeline is connected to a first nitrogen reflux pipe, the first nitrogen reflux pipe is connected to the nitrogen cold storage bed, and a first nitrogen delivery pump is arranged on the first nitrogen reflux pipe.

[0010] Furthermore, in the aforementioned liquefied air energy storage system based on single-tower dehydration and decarbonization, a liquid air-nitrogen heat exchanger and a regeneration gas cooler are further provided between the output end of the liquid air pressure pump and the air input end of the expansion unit, the output end of the liquid air pressure pump is connected to the liquid air input end of the liquid air-nitrogen heat exchanger, the liquid air output end of the liquid air-nitrogen heat exchanger is connected to the inlet of the regeneration gas cooling medium pipeline in the regeneration gas cooler through a pipeline, and the outlet of the regeneration gas cooling medium pipeline in the regeneration gas cooler is connected to the air input end of the expansion unit; A nitrogen output pipe is provided on the nitrogen cold storage bed, the nitrogen output pipe is connected to the inlet of the nitrogen medium heat exchange pipe in the liquid air nitrogen heat exchanger, a second nitrogen delivery pump is provided on the nitrogen output pipe, a second nitrogen reflux pipe is provided at the outlet of the nitrogen medium heat exchange pipe in the liquid air nitrogen heat exchanger, and the second nitrogen reflux pipe is connected to the nitrogen cold storage bed; The regeneration gas output end of the regeneration gas cooler is connected to the regeneration gas moisture separator, a regeneration gas moisture separator drain pipe is arranged at the bottom of the regeneration gas moisture separator, and a regeneration gas moisture separator gas discharge pipe is arranged on the regeneration gas moisture separator; the molecular sieve adsorption tower regeneration gas output pipe is connected to the regeneration gas input end of the regeneration gas cooler.

[0011] Furthermore, in the aforementioned liquefied air energy storage system based on single-tower dehydration and decarbonization, the compressor unit connected to the separator air input pipe is a two-stage compressor unit, the two-stage compressor unit includes a first compressor and a first compression cooler, a second compressor and a second compression cooler connected in series in sequence, the air input end of the first compressor is connected to the air source, and the air output end of the second cooler is connected to the separator air input pipe on the molecular sieve moisture separator; the cold box pre-compressor unit includes: a cold box pre-compressor and a cold box pre-compression cooler connected in series in sequence.

[0012] Furthermore, the aforementioned liquefied air energy storage system based on single-tower dehydration and decarbonization further includes a water circulation system, wherein the water circulation system includes: a cooling water storage tank, the cold water temperature in the cooling water storage tank is 20°C ± 3°C, the cooling water storage tank is connected to the cooling medium inlets of the first compression cooler, the second compression cooler and the cold box pre-compression cooler through the first cooling water output pipe, the second cooling water output pipe and the third cooling water output pipe respectively, the cooling medium outlets of the first compression cooler, the second compression cooler and the cold box pre-compression cooler are all connected to the high-temperature water storage tank through pipelines, the water temperature in the high-temperature water storage tank is 200°C ± 2°C, and the pressure is 2MPa; the high-temperature water storage tank is connected to the first heater heating medium inlet of the first heater through the first high-temperature water storage tank output pipe, the first heater heating medium outlet of the first heater is connected to the first heater water outlet pipe, and the first heater water outlet pipe is connected to the medium-temperature water storage tank; the water temperature in the medium-temperature water storage tank is 40°C to 60°C; The expander assembly includes a first-stage expansion preheater, a first-stage expander, a second-stage expansion preheater, a second-stage expander, a third-stage expansion preheater, and a third-stage expander connected in series in sequence; a second high-temperature water storage tank output pipe is provided on the high-temperature water storage tank, and the second high-temperature water storage tank output pipe is connected to the preheating medium inlets of the first-stage expansion preheater, the second-stage expansion preheater, and the third-stage expansion preheater through the first-stage preheating water pipe, the second-stage preheating water pipe, and the third-stage preheating water pipe respectively; the preheating medium outlets of the first-stage expansion preheater, the second-stage expansion preheater, and the third-stage expansion preheater are connected to the medium-temperature water storage tank through a water pipe; the medium-temperature water storage tank is connected to the low-temperature water storage tank through a water cooler.

[0013] Furthermore, in the aforementioned liquefied air energy storage system based on single-tower dehydration and decarbonization, a temperature regulating valve is provided on the output pipe of the first high-temperature water storage tank, a frequency converter is provided on the electric heater, and an air temperature sensor is provided at the heated medium outlet of the first heater of the first heater, and the air temperature sensor is interlocked with the temperature regulating valve and the frequency converter temperature signal.

[0014] The advantages of the present invention are: 1. A single molecular sieve adsorption tower is set up, and the single tower adsorption and regeneration are operated intermittently, which effectively saves equipment costs and reduces the equipment volume. The air at the air output end of the expansion unit is used for backblowing to achieve the regeneration of the molecular sieve adsorption tower, which further effectively reduces the cost of the entire equipment. 2. The filler in the molecular sieve adsorption tower adopts a combination of a 13X molecular sieve layer and an activated alumina desiccant layer, which can not only greatly improve the dehydration and decarbonization effect, but also remove the carbon dioxide in the air to below 1ppm and the water content to below 5ppm. It can also effectively shorten the regeneration time, and usually regeneration can be completed within 7-9 hours. Therefore, it can ensure that regeneration is completed at the same time during the energy release stage, ensuring that the next energy storage work is carried out normally, that is, ensuring the efficient and normal operation of the liquefied air energy storage system based on single-tower dehydration and decarbonization. 3. The frequency converter of the temperature regulating valve and the electric heater is provided on the output pipe of the first high-temperature water storage tank, and the signal of the air temperature sensor at the outlet of the heated medium of the first heater is interlocked. The flow of the temperature regulating valve is first opened to increase the temperature of the hot blowing gas. If the flow of the temperature regulating valve is the maximum and the set temperature has not been reached, the electric heater is turned on again. This can make full use of the heat of the high-temperature water in the high-temperature water storage tank, save electric energy, and ensure that the hot blowing gas for regeneration reaches the set temperature. 3. The high-temperature water generated by the compressor unit is used as the heating medium to heat the air for regeneration of the molecular sieve adsorption tower, which makes full use of the thermal energy and effectively saves energy consumption, thereby reducing the operating cost of the entire liquefied air energy storage system. 4. The setting and signal interlock of the electric heater with frequency converter and the air temperature sensor can ensure that the temperature of the air for regeneration of the molecular sieve adsorption tower is at the set value, thereby ensuring the efficiency of the regeneration of the molecular sieve adsorption tower. 5. The entire liquefied air energy storage system has a simple structure and low energy consumption. It can store energy during the trough period of electricity prices at night and release energy during the peak period of electricity prices during the day. It has high energy storage density and large energy storage capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the principle structure of a liquefied air energy storage system based on single-tower dehydration and decarbonization described in the present invention.

[0016] Figure 2 It is a schematic diagram of the laying structure of the filler in the molecular sieve adsorption tower in the liquefied air energy storage system based on single-tower dehydration and decarbonization.

[0017] Figure 3 yes Figure 1 Schematic diagram of the enlarged structure on the A side of the center OO axis.

[0018] Figure 4 yes Figure 1 Schematic diagram of the enlarged structure on the B side of the center OO axis. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0020] like Figure 1 , Figure 3 , Figure 4 As shown, a liquefied air energy storage system based on single-tower dehydration and decarbonization includes: a molecular sieve water separator 1 for removing free water in the air and a molecular sieve adsorption tower 2 for removing carbon dioxide and moisture in the air. The molecular sieve water separator 1 is connected to a separator air input pipe 11, a separator air output pipe 12 and a separator drain pipe 13. The separator air input pipe 11 is connected to a two-stage compressor unit. The two-stage compressor unit includes a first compressor 401 and a first compression cooler 402, a second compressor 403 and a second compression cooler 404 connected in series in sequence. The air input end of the first compressor 401 is connected to an air source, which usually refers to filtered clean air. The air output end of the second compression cooler 404 is connected to the separator air input pipe 11. As shown Figure 2 As shown, the filler in the molecular sieve adsorption tower 2 includes a 13X molecular sieve layer 2001 and an activated alumina desiccant layer 2002 arranged in sequence from bottom to top; a 10 cm thick porcelain ball layer 2003 is arranged at the bottom of the 13X molecular sieve layer 2001, a 5-8 cm porcelain ball layer is laid between the 13X molecular sieve layer and the activated alumina desiccant layer for separation, and a stainless steel wire mesh 2004 is arranged on the top of the activated alumina desiccant layer. When air enters the molecular sieve adsorption tower 2 from top to bottom, most of the water can be removed first, and then carbon dioxide and water can be removed in depth.

[0021] The separator air outlet pipe 12 is connected to the top gas pipe 21 of the molecular sieve adsorption tower 2. The bottom gas pipe 22 of the molecular sieve adsorption tower 2 is connected to the air input end of the cold box pre-compressor unit. The cold box pre-compressor unit includes: a cold box pre-compressor 405 and a cold box pre-compression cooler 406 connected in series. A bottom gas pipe control valve 221 is provided on the bottom gas pipe 22.

[0022] The exhaust end of the cold box front compressor unit is connected to the inlet of the first air pipeline 31 in the cold box 3. The outlet of the first air pipeline 31 in the cold box 3 is connected to the first liquefied air output pipe 34 with a first throttle valve 341. The first liquefied air output pipe 34 is connected to the first liquefied air storage tank 4.

[0023] The first liquefied air storage tank output pipe 41 of the first liquefied air storage tank 4 is connected to the liquid air booster pump 411, and the output end of the liquid air booster pump 411 is connected to the air input end of the expansion unit. The expansion unit includes a primary expansion preheater 51, a primary expansion machine 52, a secondary expansion preheater 53, a secondary expansion machine 54, a tertiary expansion preheater 55, and a tertiary expansion machine 56 connected in series in sequence. The air input end of the expansion unit is the air input end 511 of the primary expansion preheater 51. The air output end of the expansion unit is the air output end 561 of the tertiary expansion machine 56.

[0024] The air output end 561 of the three-stage expander 56 is provided with a hot air delivery pipe 57 with a hot air output control valve 571, a cold air delivery pipe 58 with a cold air output control valve 581, and an expander discharge pipe 59. When the system needs to use hot air, the hot air output control valve 571 is opened. When cold air is needed, the cold air output control valve 581 is opened. When the gas needs to be discharged, the air at the air output end 561 of the three-stage expander 56 is discharged from the expander discharge pipe 59.

[0025] The hot air blowing conveying pipe 27 is connected to the first heater heated medium inlet 61 of the first heater 6, and the first heater heated medium outlet 62 is connected to the inlet of the electric heater 7. The outlet of the electric heater 7 is provided with an electric heater output pipe 71, and the air temperature output by the electric heater output pipe 71 is controlled at 195°C to 200°C. The output end of the electric heater output pipe 71 is provided with a back-blowing control valve 711 and a first check valve 712. The electric heater output pipe 71 is connected to the bottom gas pipe 22 between the molecular sieve adsorption tower 2 and the bottom gas pipe control valve 221. The output end of the cold air blowing conveying pipe 58 is connected to the output end of the electric heater output pipe 71, and the output end of the cold air blowing conveying pipe 58 is provided with a second check valve 582. The top gas pipe 21 of the molecular sieve adsorption tower 2 is connected with a molecular sieve adsorption tower regeneration gas output pipe 23, and the molecular sieve adsorption tower regeneration gas output control valve 231 is provided on the molecular sieve adsorption tower regeneration gas output pipe 23. When the molecular sieve adsorption tower 2 is regenerated, the molecular sieve adsorption tower regeneration gas output control valve 231 and the backwash control valve 711 are opened, and the bottom gas take-over control valve 221 is closed.

[0026] In order to save energy and make full use of the cooling capacity of liquid air in this embodiment, a second air pipeline 32 is also provided in the cold box 3, and the air output end of the cold box front compressor unit is also connected to the inlet of the second air pipeline 32 in the cold box 3, and the outlet of the second air pipeline 32 is connected to the second liquefied air output pipe 35 with a second throttle valve 351, and the second liquefied air output pipe 35 is connected to the second liquefied air storage tank 8. A cooling medium liquid air pipeline 36 is provided in the cold box 3, and the second liquefied air tank output pipe 81 on the second liquefied air storage tank 8 is connected to the inlet of the cooling medium liquid air pipeline 36 in the cold box 3; a low-temperature air pipeline 33 is provided in the cold box 3, and the second liquefied air tank low-temperature air output pipe 82 on the top of the second liquefied air storage tank 8 is connected to the inlet of the low-temperature air pipeline 33 in the cold box 3, and the outlet of the cooling medium liquid air pipeline 36 and the outlet of the low-temperature air pipeline 33 are both connected to the air input end of the cold box front compressor unit, that is, the air input end of the cold box front compressor 405.

[0027] Other refrigerant pipelines are also provided in the cold box 3. The refrigerant is not limited as long as it can provide sufficient cooling capacity for air liquefaction. In this embodiment, the cooling medium is liquefied natural gas. The cooling medium pipeline is an LNG pipeline 37, and the inlet of the LNG pipeline 37 is connected to a liquefied natural gas input pipe 371, and the outlet of the LNG pipeline 37 is connected to a liquefied natural gas output pipe 372.

[0028] A low-temperature nitrogen pipeline 38 is also provided in the cold box 3, and the low-temperature nitrogen in the low-temperature nitrogen pipeline 38 is also used as a refrigerant for the cold box. The inlet of the low-temperature nitrogen pipeline 38 is connected to a nitrogen input pipe 381, which is connected to the nitrogen cold storage bed 9, and the outlet of the nitrogen input pipe 381 is connected to a first nitrogen return pipe 382, ​​which is connected to the nitrogen cold storage bed 9, and a first nitrogen delivery pump 383 is provided on the first nitrogen return pipe 382.

[0029] In this embodiment, a liquid air nitrogen heat exchanger 10 and a regeneration gas cooler 20 are also provided between the output end of the liquid air booster pump 411 and the air input end of the expansion unit, that is, between the output end of the liquid air booster pump 411 and the air input end 511 of the primary expansion preheater 51. The output end of the liquid air booster pump 411 is connected to the liquid air input end 101 of the liquid air nitrogen heat exchanger 10, and the liquid air output end 102 of the liquid air nitrogen heat exchanger 10 is connected to the regeneration gas cooling medium pipeline inlet 201 in the regeneration gas cooler 20 through a pipeline, and the regeneration gas cooling medium pipeline outlet 202 in the regeneration gas cooler 20 is connected to the air input end of the expansion unit, that is, connected to the air input end 511 of the primary expansion preheater 51. The output low-temperature air of the liquid air booster pump 411 is used as the refrigerant in the liquid air nitrogen heat exchanger 10 and the regeneration gas cooler 20 in turn.

[0030] A nitrogen output pipe 91 is provided on the nitrogen cold storage bed 9, and the nitrogen output pipe 91 is connected to the nitrogen medium heat exchange pipe inlet 103 in the liquid air nitrogen heat exchanger 10, and a second nitrogen delivery pump 911 is provided on the nitrogen output pipe 91; a second nitrogen return pipe 92 is provided at the nitrogen medium heat exchange pipe outlet 104 in the liquid air nitrogen heat exchanger 9, and the second nitrogen return pipe 92 is connected to the liquid nitrogen storage tank 9. Nitrogen returns to the nitrogen cold storage bed 9 after heat exchange with low-temperature air in the liquid air nitrogen heat exchanger 10 to obtain cold. The temperature of the low-temperature nitrogen in the nitrogen cold storage bed is maintained at -140°C to -142°C.

[0031] The regeneration gas output end 204 of the regeneration gas cooler 20 is connected to the regeneration gas moisture separator 30, and a regeneration gas moisture separator drain pipe 301 is provided at the bottom of the regeneration gas moisture separator 30, and a regeneration gas moisture separator gas discharge pipe 302 is provided on the regeneration gas moisture separator 30. The molecular sieve adsorption tower regeneration gas output pipe 23 is connected to the regeneration gas input end 203 of the regeneration gas cooler 20.

[0032] The present embodiment also includes a water circulation system, which includes: a cooling water storage tank 50, the temperature of the cold water in the cooling water storage tank 50 is 20°C ± 3°C, the cooling water storage tank 50 is connected to the cooling medium inlet of the first compression cooler 402, the second compression cooler 404 and the cold box front compression cooler 406 through the first cooling water output pipe 501, the second cooling water output pipe 502, and the third cooling water output pipe 503, respectively, and the cooling medium outlets of the first compression cooler 402, the second compression cooler 404 and the cold box front compression cooler 406 are all connected to the high-temperature water storage tank 60 through pipelines. The water temperature in the high-temperature water storage tank 60 is 200°C ± 2°C and the pressure is 2MPa. The cold water in the cooling water storage tank 50 is used as the cooling medium in the first compression cooler 402, the second compression cooler 404 and the cold box front compression cooler 406. The high temperature water storage tank 60 is connected to the first heater heating medium inlet 63 of the first heater 6 through the first high temperature water storage tank output pipe 601, and the first heater heating medium outlet 64 of the first heater 6 is connected to the first heater outlet pipe 65, and the first heater outlet pipe 65 is connected to the medium temperature water storage tank 70. The water temperature in the medium temperature water storage tank 70 is 40℃~60℃; In order to ensure that the air temperature output by the electric heater output pipe 71 is controlled at 195°C ~ 200°C, in this embodiment, a temperature regulating valve 6011 is provided on the first high-temperature water storage tank output pipe 601, the electric heater 7 is provided with a frequency converter 72, and an air temperature sensor 621 is provided on the pipeline of the first heater heated medium outlet 62 of the first heater 6. The air temperature sensor 621 is interlocked with the temperature regulating valve 6011 and the temperature signal of the frequency converter 72.

[0033] The high temperature water storage tank 60 is provided with a second high temperature water storage tank output pipe 602, which is connected to the preheating medium inlets of the first expansion preheater 51, the second expansion preheater 53, and the third expansion preheater 55 through the first preheating water pipe 6021, the second preheating water pipe 6022, and the third preheating water pipe 6023, respectively. The preheating medium outlets of the first expansion preheater 51, the second expansion preheater 53, and the third expansion preheater 55 are connected to the medium temperature water storage tank 70 through water pipes; the medium temperature water storage tank 70 is connected to the low temperature water storage tank 50 through the water cooler 701. The high temperature water in the high temperature water storage tank 60 is used as the preheating medium of the first expansion preheater 51, the second expansion preheater 53, and the third expansion preheater 55, and the water after releasing the heat is then merged into the medium temperature water storage tank.

[0034] The working principle is as follows: A liquefied air energy storage system described in this application has an energy storage process and an energy release process.

[0035] Energy storage process: This process is generally carried out during the trough period of electricity prices at night. The air at 0℃~35℃ and normal pressure from the outside is compressed and cooled by the first compressor 401, the first compression cooler 402, the second compressor 403 and the second compression cooler 404. The two-stage compressor unit forms air with a pressure of 1~4MPa, 30℃~35℃ and free water. The air with a pressure of 1~4MPa, 30℃~35℃ and free water enters the molecular sieve water separator 1 through the separator air inlet pipe 11. The molecular sieve water separator 1 removes the free water generated by compression condensation in the air in advance. The air without free water enters the molecular sieve adsorption tower 2 through the separator air outlet pipe 12. The molecular sieve adsorption tower 2 removes carbon dioxide from the air and further removes moisture. Since the filler in the molecular sieve adsorption tower 2 includes a 13X molecular sieve layer 2001 and an activated alumina desiccant layer 2002 arranged in sequence from bottom to top, the use of the above two fillers is intended to improve the adsorption efficiency and effect, and can remove carbon dioxide in the air to below 1ppm, and remove the water content to below 5ppm.

[0036] The air from which carbon dioxide and water have been removed from the molecular sieve adsorption tower 2 enters the cold box pre-compressor 405 and the cold box pre-compression cooler 406 in sequence through the bottom gas pipe 22, and is pressurized and cooled to form air at 7-10 MPa and 30°C-35°C. It is then divided into two streams and enters the first air pipeline 31 and the second air pipeline 32 in the cold box 3, respectively, and the air is cooled in the first air pipeline 31 and the second air pipeline 32. The cooled air discharged from the first air pipeline 31 is throttled and liquefied by the first throttle valve 341, and the liquefied air enters the first liquefied air storage tank 4 through the first liquefied air output pipe 34 for storage, thereby realizing the liquefaction of air for energy storage. The cooled air discharged from the second air pipeline 32 is throttled and liquefied by the second throttle valve 351, and the liquefied air enters the second liquefied air storage tank 8 for storage through the second liquefied air output pipe 35. The pressure of the liquefied air in the first liquefied air storage tank 4 and the second liquefied air storage tank 8 is 1.9 MPa to 2.0 MPa, and the temperature is -156°C.

[0037] Among them, the liquid air in the second liquefied air storage tank 8 enters the cooling medium liquid air pipeline 36 in the cold box 3 through the second liquefied air storage tank output pipe 81, and the low-temperature air generated by gasification in the second liquefied air storage tank 8 enters the low-temperature air pipeline 33 in the cold box 3 through the second liquefied air storage tank low-temperature air output pipe 82. The liquid air in the second liquefied air storage tank 8 and the vaporized air are both used as cooling medium in the cold box 3. The air in the cooling medium liquid air pipeline 36 and the low-temperature air pipeline 33 that has released cold energy enters the cold box front compressor 405 and merges with the air in the bottom gas connecting pipe 22 for pressurized cooling again.

[0038] In the above energy storage process, the cold capacity in the cold box 3 is provided by the liquefied natural gas in the LNG pipeline 37, the cryogenic nitrogen in the cryogenic nitrogen pipeline 38, the liquid air in the cooling medium liquid air pipeline 36, and the cryogenic air in the cryogenic air pipeline 33. Liquid air and cryogenic air as refrigerants can correspondingly reduce the amount of liquefied natural gas in the LNG pipeline 37 and the cryogenic nitrogen in the cryogenic nitrogen pipeline 38, thereby playing a role in saving energy consumption.

[0039] During the above energy storage operation, the cold water in the cooling water storage tank 50 with a temperature of 20°C ± 3°C is transported to the first compression cooler 402, the second compression cooler 404 and the cold box pre-compression cooler 406 as a cooling medium through the first cooling water output pipe 501, the second cooling water output pipe 502 and the third cooling water output pipe 503, respectively, and the compressed air at each stage is cooled. The water that has absorbed heat in the first compression cooler 402, the second compression cooler 404 and the cold box pre-compression cooler 406 enters the high-temperature water storage tank 60 through the pipeline from their respective cooling medium outlets. The temperature of the high-temperature water in the high-temperature water storage tank 60 is 200°C ± 2°C and the pressure is 2MPa.

[0040] The energy release process is as follows: During the peak period of electricity prices during the day, in order to save electricity, the liquid air stored in the first liquefied air storage tank 4 is used to generate electricity.

[0041] The liquid air in the first liquefied air storage tank 4 is pressurized to 10 MPa to 12 MPa through the first liquefied air storage tank output pipe 41 and the liquid air booster pump 411, and then enters the liquid air nitrogen heat exchanger 10 to exchange heat with nitrogen to release part of the heat energy, and then enters the regeneration gas cooler 20 to release part of the heat energy, and then respectively passes through the primary expansion preheater 51, the primary expansion machine 52, the secondary expansion preheater 53, the secondary expansion machine 54, the tertiary expansion preheater 55, and the tertiary expansion machine 56 for three-stage expansion. The kinetic energy outputted from the kinetic energy output end of the tertiary expansion machine 56 drives the steam turbine to generate power, thereby realizing the conversion of liquid air energy. The generated electric energy can be used by electrical equipment.

[0042] During the above working process, the high temperature water in the high temperature water storage tank 60 enters the first expansion preheater 51, the second expansion preheater 53, and the third expansion preheater 55 through the first preheating water pipe 6021, the second preheating water pipe 6022, and the third preheating water pipe 6023, respectively, so as to preheat the air to be expanded. The preheating medium outlets of the first expansion preheater 51, the second expansion preheater 53, and the third expansion preheater 55 release heat and enter the medium temperature water storage tank 70 through the water pipe. The water temperature in the medium temperature water storage tank 70 is 40℃~60℃. The water in the medium temperature water storage tank 70 is cooled by the water cooler 701 and then flows back to the low temperature water storage tank 50.

[0043] In order to achieve the regeneration of the molecular sieve adsorption tower 2, the air at the air output end of the three-stage expander 56 is used as the back-blowing gas for the regeneration of the molecular sieve adsorption tower 2, and first enters the first heater 6 through the hot blowing conveying pipe 57 for heating. The heating medium in the first heater 6 uses the high-temperature water in the high-temperature water storage tank 60. The heated high-temperature air enters the electric heater 7 through the heated medium outlet 62 of the first heater. In order to ensure that the air temperature output by the electric heater output pipe 71 is controlled at 195°C to 200°C, the air temperature sensor 621 is interlocked with the temperature regulating valve 6011 and the frequency converter 72 temperature signal. When the air temperature detected by the air temperature sensor 621 does not reach the set value, the temperature regulating valve 6011 increases the flow rate to increase the air temperature output by the electric heater output pipe 71. If the flow rate of the temperature regulating valve 6011 reaches the maximum, the air temperature output by the electric heater output pipe 71 still does not reach the set temperature value, then the frequency converter 71 controls the electric heater 7 to work and electrically heat the passing air, so that the temperature of the back-blowing air reaches the set value. The advantage of the temperature signal interlocking of the air temperature sensor 621 with the temperature regulating valve 6011 and the frequency converter 72 is that it can not only fully utilize the thermal energy of the high-temperature water, but also ensure that the air temperature output by the electric heater output pipe 71 is controlled at 195°C ~ 200°C, thereby ensuring the effect and efficiency of the regeneration of the molecular sieve adsorption tower 2.

[0044] The high-temperature air in the electric heater 7 enters the molecular sieve adsorption tower 2 through the electric heater output pipe 71, the first check valve 712, the back-blowing control valve 711, and the bottom gas pipe 22 to heat-blow the bed layer in the molecular sieve adsorption tower 2. The air containing water and carbon dioxide generated by the hot blowing enters the regeneration gas cooler 20 from the top gas pipe 21 of the molecular sieve adsorption tower 2 and the molecular sieve adsorption tower regeneration gas output pipe 23 to be cooled, and finally enters the regeneration gas moisture separator 30 to remove water and then is discharged from the regeneration gas moisture separator gas discharge pipe 302. The water generated in the regeneration gas moisture separator 30 is discharged from the regeneration gas moisture separator drain pipe 301.

[0045] After the hot blowing is completed, cold blowing is performed. The air at the air output end of the three-stage expander 56 is used as the back-blowing gas for the regeneration of the molecular sieve in the molecular sieve adsorption tower 2, and enters the molecular sieve adsorption tower 2 through the cold blowing gas delivery pipe 58, the second check valve 582, the first check valve 712, the back-blowing control valve 711, and the bottom gas connection pipe 22 to perform cold blowing on the bed layer in the molecular sieve adsorption tower 2. The gas generated by the cold blowing enters the regeneration gas cooler 20 from the top gas connection pipe 21 of the molecular sieve adsorption tower 2 and the molecular sieve adsorption tower regeneration gas output pipe 23 to be cooled, and finally enters the regeneration gas moisture separator 30 to remove water and is discharged from the regeneration gas moisture separator gas discharge pipe 302. The water generated in the regeneration gas moisture separator 30 is discharged from the regeneration gas moisture separator drain pipe 301.

[0046] After cold blowing and hot blowing, the molecular sieve adsorption tower 2 is regenerated. Since the filler in the molecular sieve adsorption tower 2 includes a 13X molecular sieve layer 2001 and an activated alumina desiccant layer 2002 arranged from bottom to top, the use of this combination of fillers can not only improve the removal effect of carbon dioxide and water, but also effectively shorten the regeneration time, usually within 7-9 hours to complete the regeneration, so that the single tower can be ensured to have enough regeneration time to prepare in advance for the next liquid air energy storage work.

[0047] During the period of liquid air releasing energy, the molecular sieve adsorption tower 2 is regenerated to prepare for liquid air energy storage during the trough period of electricity prices, thereby realizing single-tower adsorption and saving equipment costs.

[0048] It can be seen that the liquefied air energy storage system described in this application has the following advantages: 1. A single molecular sieve adsorption tower is set up, and the single tower adsorption and regeneration are operated intermittently, which effectively saves equipment costs and reduces the equipment volume. The air at the air output end of the expansion unit is used for backblowing to achieve the regeneration of the molecular sieve adsorption tower, which further effectively reduces the cost of the entire equipment. 2. The filler in the molecular sieve adsorption tower adopts a combination of a 13X molecular sieve layer and an activated alumina desiccant layer, which can not only greatly improve the dehydration and decarbonization effect, but also remove carbon dioxide from the air to below 1ppm and remove water content to below 5ppm. It can also effectively shorten the regeneration time, usually within 7-9 hours. Regeneration can be completed, so it can ensure that regeneration is completed at the same time during the energy release stage, ensuring that the next energy storage work is carried out normally, that is, ensuring the efficient and normal operation of the liquefied air energy storage system based on single-tower dehydration and decarbonization. 3. The frequency converter of the temperature regulating valve and the electric heater is provided on the output pipe of the first high-temperature water storage tank, and the signal of the air temperature sensor at the outlet of the heated medium of the first heater is interlocked. The flow of the temperature regulating valve is first opened to increase the temperature of the hot blowing gas. If the flow of the temperature regulating valve is the maximum and the set temperature has not been reached, the electric heater is turned on again. This can make full use of the heat of the high-temperature water in the high-temperature water storage tank, save electric energy, and ensure that the hot blowing gas for regeneration reaches the set temperature. 3. The high-temperature water generated by the compressor unit is used as the heating medium to heat the air for regeneration of the molecular sieve adsorption tower, which makes full use of the thermal energy and effectively saves energy consumption, thereby reducing the operating cost of the entire liquefied air energy storage system. 4. The setting and signal interlock of the electric heater with frequency converter and the air temperature sensor can ensure that the temperature of the air for regeneration of the molecular sieve adsorption tower is at the set value, thereby ensuring the efficiency of the regeneration of the molecular sieve adsorption tower. 5. The entire liquefied air energy storage system has a simple structure and low energy consumption. It can store energy during the trough period of electricity prices at night and release energy during the peak period of electricity prices during the day. It has high energy storage density and large energy storage capacity.

Claims

1. A liquefied air energy storage system based on single-tower dehydration and decarbonization, comprising: A molecular sieve water separator for removing free water from the air and a molecular sieve adsorption tower for removing carbon dioxide and moisture from the air, characterized in that: the filler in the molecular sieve adsorption tower comprises a 13X type molecular sieve layer and an activated alumina desiccant layer arranged in sequence from bottom to top; the molecular sieve water separator is connected with a separator air input pipe, a separator air output pipe and a separator liquid discharge pipe, the separator air input pipe is connected with a compressor unit, and the air pressure delivered to the separator air input pipe after being compressed and cooled by the compressor unit is controlled at 1.0-4.0MPa and the temperature is 30°C-35°C, and the separator air output pipe is connected with the compressor unit. The outlet pipe is connected to the top gas pipe of the molecular sieve adsorption tower, the bottom gas pipe of the molecular sieve adsorption tower is connected to the air input end of the cold box front compressor unit, a bottom gas pipe control valve is provided on the bottom gas pipe, the air output end of the cold box front compressor unit is communicated with the inlet of the air pipeline in the cold box, the outlet of the air pipeline in the cold box is connected to the first liquefied air output pipe with a first throttle valve, the first liquefied air output pipe is connected to the first liquefied air storage tank, the pressure of the liquid air in the first liquefied air storage tank is 1.9MPa~2.0MPa, and the temperature is -156℃; the first liquefied air storage tank The output pipe of the first liquefied air storage tank is provided with a liquid air booster pump, which pressurizes the liquid air to 10.0MPa-12.0MPa. The output end of the liquid air booster pump is connected to the air input end of the expansion unit. The air output end of the expansion unit is provided with a hot air delivery pipe with a hot air output control valve, a cold air delivery pipe with a cold air output control valve and an expander discharge pipe. The hot air delivery pipe is connected to the first heater heated medium inlet of the first heater, the first heater heated medium outlet is connected to the inlet of the electric heater, and the outlet of the electric heater is provided with an electric heater output. The output pipe of the electric heater is connected to the bottom gas connecting pipe between the molecular sieve adsorption tower and the bottom gas connecting pipe control valve, the output end of the electric heater output pipe is provided with a first check valve and a first back-blowing control valve, and the air temperature output by the electric heater output pipe is controlled at 195°C-200°C; the output end of the cold blowing air delivery pipe is connected to the output end of the electric heater output pipe, and the output end of the cold blowing air delivery pipe is provided with a second check valve; the top gas connecting pipe of the molecular sieve adsorption tower is connected with a molecular sieve adsorption tower regeneration gas output pipe, and a molecular sieve adsorption tower regeneration gas output control valve is provided on the molecular sieve adsorption tower regeneration gas output pipe.

2. A liquefied air energy storage system based on single-tower dehydration and decarbonization according to claim 1, characterized in that: A 10 cm thick porcelain ball layer is arranged at the bottom of the 13X molecular sieve layer, a 5-8 cm porcelain ball layer is laid between the 13X molecular sieve layer and the activated alumina desiccant layer for separation, and a stainless steel wire mesh is arranged on the top of the activated alumina desiccant layer.

3. A liquefied air energy storage system based on single-tower dehydration and decarbonization according to claim 1 or 2, characterized in that: A second air pipeline is also provided in the cold box, and the air output end of the cold box front compressor unit is also connected to the inlet of the second air pipeline in the cold box, and the outlet of the second air pipeline is connected to a second liquefied air output pipe with a second throttle valve, and the second liquefied air output pipe is connected to the second liquefied air storage tank; a cooling medium liquid-to-air pipeline is provided in the cold box, and the second liquefied air storage tank output pipe on the second liquefied air storage tank is connected to the inlet of the cooling medium liquid-to-air pipeline in the cold box; a low-temperature air pipeline is also provided in the cold box, and the second liquefied air storage tank low-temperature air output pipe on the top of the second liquefied air storage tank is connected to the inlet of the low-temperature air pipeline in the cold box, and the outlet of the cooling medium liquid-to-air pipeline and the outlet of the low-temperature air pipeline are both connected to the air input end of the cold box front compressor unit.

4. A liquefied air energy storage system based on single-tower dehydration and decarbonization according to claim 1 or 2, characterized in that: An LNG pipeline is arranged in the cold box, an inlet of the LNG pipeline is connected to a liquefied natural gas input pipe, and an outlet of the LNG pipeline is connected to a liquefied natural gas output pipe.

5. A liquefied air energy storage system based on single-tower dehydration and decarbonization according to claim 1 or 2, characterized in that: A low-temperature nitrogen pipeline is arranged in the cold box, the inlet of the low-temperature nitrogen pipeline is connected with a nitrogen input pipe, the nitrogen input pipe is connected with a nitrogen cold storage bed, the temperature of the low-temperature nitrogen in the nitrogen cold storage bed is maintained at -140°C to -142°C, the outlet of the low-temperature nitrogen pipeline is connected with a first nitrogen reflux pipe, the first nitrogen reflux pipe is connected to the nitrogen cold storage bed, and a first nitrogen delivery pump is arranged on the first nitrogen reflux pipe.

6. A liquefied air energy storage system based on single-tower dehydration and decarbonization according to claim 5, characterized in that: A liquid air nitrogen heat exchanger and a regeneration gas cooler are also provided between the output end of the liquid air pressure pump and the air input end of the expansion unit. The output end of the liquid air pressure pump is connected to the liquid air input end of the liquid air nitrogen heat exchanger. The liquid air output end of the liquid air nitrogen heat exchanger is connected to the inlet of the regeneration gas cooling medium pipeline in the regeneration gas cooler through a pipeline. The outlet of the regeneration gas cooling medium pipeline in the regeneration gas cooler is connected to the air input end of the expansion unit. A nitrogen output pipe is provided on the nitrogen cold storage bed, the nitrogen output pipe is connected to the inlet of the nitrogen medium heat exchange pipe in the liquid air nitrogen heat exchanger, a second nitrogen delivery pump is provided on the nitrogen output pipe, a second nitrogen reflux pipe is provided at the outlet of the nitrogen medium heat exchange pipe in the liquid air nitrogen heat exchanger, and the second nitrogen reflux pipe is connected to the nitrogen cold storage bed; The regeneration gas output end of the regeneration gas cooler is connected to the regeneration gas moisture separator, a regeneration gas moisture separator drain pipe is arranged at the bottom of the regeneration gas moisture separator, and a regeneration gas moisture separator gas discharge pipe is arranged on the regeneration gas moisture separator; the molecular sieve adsorption tower regeneration gas output pipe is connected to the regeneration gas input end of the regeneration gas cooler.

7. A liquefied air energy storage system based on single-tower dehydration and decarbonization according to claim 1 or 2, characterized in that: The compressor unit connected to the separator air input pipe is a two-stage compressor unit, which includes a first compressor and a first compression cooler, a second compressor and a second compression cooler connected in series in sequence, the air input end of the first compressor is connected to an air source, and the air output end of the second cooler is connected to the separator air input pipe on the molecular sieve moisture separator; The cold box pre-compressor unit comprises: a cold box pre-compressor and a cold box pre-compression cooler which are sequentially connected in series.

8. A liquefied air energy storage system based on single-tower dehydration and decarbonization according to claim 7, characterized in that: It also includes a water circulation system, which includes: a cooling water storage tank, the temperature of cold water in the cooling water storage tank is 20℃±3℃, the cooling water storage tank is connected to the cooling medium inlets of the first compression cooler, the second compression cooler and the cold box front compression cooler through the first cooling water output pipe, the second cooling water output pipe and the third cooling water output pipe respectively, the cooling medium outlets of the first compression cooler, the second compression cooler and the cold box front compression cooler are all connected to the high-temperature water storage tank through pipelines, the water temperature in the high-temperature water storage tank is 200℃±2℃, and the pressure is 2MPa; the high-temperature water storage tank is connected to the first heater heating medium inlet of the first heater through the first high-temperature water storage tank output pipe, the first heater heating medium outlet of the first heater is connected to the first heater water outlet pipe, and the first heater water outlet pipe is connected to the medium-temperature water storage tank; the water temperature in the medium-temperature water storage tank is 40℃~60℃; The expander assembly includes a first-stage expansion preheater, a first-stage expander, a second-stage expansion preheater, a second-stage expander, a third-stage expansion preheater, and a third-stage expander connected in series in sequence; a second high-temperature water storage tank output pipe is provided on the high-temperature water storage tank, and the second high-temperature water storage tank output pipe is connected to the preheating medium inlets of the first-stage expansion preheater, the second-stage expansion preheater, and the third-stage expansion preheater through the first-stage preheating water pipe, the second-stage preheating water pipe, and the third-stage preheating water pipe respectively; the preheating medium outlets of the first-stage expansion preheater, the second-stage expansion preheater, and the third-stage expansion preheater are connected to the medium-temperature water storage tank through a water pipe; the medium-temperature water storage tank is connected to the low-temperature water storage tank through a water cooler.

9. A liquefied air energy storage system based on single-tower dehydration and decarbonization according to claim 8, characterized in that: A temperature regulating valve is arranged on the output pipe of the first high-temperature water storage tank, a frequency converter is arranged on the electric heater, an air temperature sensor is arranged at the outlet of the first heater heated medium of the first heater, and the air temperature sensor is interlocked with the temperature regulating valve and the frequency converter temperature signal.

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