A fully liquid air separation unit with independent phases for air refrigeration liquefaction and air separation distillation.

Abstract

This utility model discloses a fully liquid air separation unit with independent air refrigeration liquefaction and air separation distillation, belonging to the fields of liquid-air energy storage and fully liquid air separation. It includes an air liquefaction system, an air distillation system, and liquid-air, liquid oxygen, liquid nitrogen, and liquid argon storage tanks. The air liquefaction system includes a liquefied feedstock air compressor, a liquefied refrigerated dryer, a liquefied molecular sieve, a circulating compressor, a hot-end expander, a hot-end cooler, a cold-end expander, a cold-end cooler, a hot-end heat exchanger, and a cold-end heat exchanger. The air distillation system includes a distillation feedstock air compressor, a distillation nitrogen-water precooling system, a distillation molecular sieve, a main heat exchanger, a distillation column, a distillation subcooler, a crude argon column, and a refined argon column. The liquid-air storage tank is located between the two systems as a buffer connection. Air liquefaction and distillation operate independently, coupled with the liquid-air storage tank, allowing for time-of-use operation, utilizing off-peak electricity to reduce costs, and improving efficiency and stability.

Description

Technical Field

[0001] This utility model belongs to the field of liquid-air energy storage technology, and relates to a fully liquid air separation device in which air refrigeration liquefaction and air separation distillation are independent phases. Background Technology

[0002] Air liquefaction (ALD) is a technology that utilizes air liquefaction to store energy. It involves compressing, cooling, and liquefying air into liquid air for storage, then revaporizing it to release energy when needed. This technology plays a crucial role in energy management, particularly in addressing the volatility of renewable energy sources to achieve peak-valley regulation. Air refrigeration liquefaction primarily refers to the process of cooling air to extremely low temperatures (approximately -183°C or below) using equipment such as air compressors, precooling systems, purification systems, and expanders, completely liquefying it. The product is a multi-component mixture of liquid air, free of moisture, carbon dioxide, and hydrocarbons. This process involves multi-stage compression, heat exchange, and expansion to achieve a highly efficient refrigeration cycle. Traditional air refrigeration liquefaction systems are often integrated with air separation and distillation systems, leading to overall system inefficiency because fluctuations at the front end directly affect the back end operation.

[0003] Air separation distillation refers to the process of obtaining high-purity oxygen, nitrogen, and argon by utilizing the different boiling points of the components (mainly nitrogen and oxygen) in a mixed gas in a distillation column (including the lower and upper columns) through multiple partial evaporations and condensations. This process relies on precise temperature and pressure control, and the extraction of the argon fraction through crude and refined argon columns. In traditional integrated systems, the air compressor, expander, and distillation column are directly linked. Any fluctuations at the upstream end (such as changes in air pressure or temperature) are directly transmitted to the distillation column, affecting product purity and yield. This makes it difficult for the system to operate stably under varying load conditions, easily leading to energy waste and uneven product quality.

[0004] Conventional all-liquid air separation processes suffer from low efficiency and high cost. Traditional systems cannot effectively utilize off-peak electricity prices because the liquefaction and distillation systems are tightly coupled, making it difficult to operate the entire unit across different time periods. Air separation systems cannot be frequently started and stopped, otherwise it will cause changes in internal stress and even leakage risks. While liquefaction systems can be started and stopped relatively quickly, their integrated design limits their flexibility. Furthermore, the limited number of expanders in traditional processes restricts liquid air production capacity, making it unable to cope with fluctuations in market demand. Liquid air storage tanks in traditional systems are often self-pressurizing, relying on internal evaporation to provide pressure, but this increases energy loss and is not conducive to the input of low-cost liquid air from the outside. The desorbed gas source for molecular sieve purification systems also often relies on external supply, increasing operating costs. Utility Model Content

[0005] In view of this, the purpose of this utility model is to solve the above problems and provide a fully liquid air separation device with independent air refrigeration liquefaction and air separation distillation phases. By setting the air liquefaction system and the air distillation system independently and using the liquid air storage tank as a buffer connection, the liquid air production and distillation are separated, reducing the overall energy consumption and improving the operational flexibility and stability.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A fully liquid air separation unit with independent air refrigeration liquefaction and air separation distillation phases includes an air liquefaction system, an air distillation system, and liquid air storage tanks, liquid oxygen storage tanks, liquid nitrogen storage tanks, and liquid argon storage tanks; The air liquefaction system includes a liquefied feedstock air compressor, a liquefied refrigerated dryer, a liquefied molecular sieve, a circulating machine, a hot-end expander, a hot-end cooler, a cold-end expander, a cold-end cooler, a hot-end heat exchanger, and a cold-end heat exchanger; the air distillation system includes a distillation feedstock air compressor, a distillation nitrogen-water precooling system, a distillation molecular sieve, a main heat exchanger, a distillation column, a distillation subcooler, a crude argon column, and a refined argon column; The liquefied air compressor is provided with a set of inlets and outlets, namely a liquefied air inlet and a liquefied air outlet; the liquefied air dryer is provided with a condensate drain outlet and a set of inlets and outlets, namely a pre-cooled air inlet and a pre-cooled air outlet. The liquefied molecular sieve is provided with two sets of inlets and outlets, namely a liquefied purified air inlet and a liquefied purified air outlet, and a liquefied waste nitrogen inlet and a liquefied waste nitrogen outlet; The circulating machine is equipped with a set of inlets and outlets, namely a circulating air inlet and a circulating air outlet; The cold end expander is provided with two sets of inlets and outlets, namely, the cold end pressurizing end air inlet and the cold end pressurizing end air outlet, the cold end expansion end air inlet and the cold end expansion end air outlet; The cold end cooler is provided with a set of inlets and outlets, namely a cold end air inlet and a cold end air outlet; The hot-end expander is provided with two sets of inlets and outlets, namely, hot-end pressurization air inlet and hot-end pressurization air outlet, hot-end expansion air inlet and hot-end expansion air outlet; The hot-end cooler is provided with a set of inlets and outlets, namely a hot-end air inlet and a hot-end air outlet; The hot end heat exchanger is provided with three sets of inlets and outlets, namely the first inlet and the first outlet of the hot end heat exchange, the second inlet and the second outlet of the hot end heat exchange, and the third inlet and the third outlet of the hot end heat exchange. The cold end heat exchanger is provided with two sets of inlets and outlets, namely a first inlet and a first outlet for cold end heat exchange, a second inlet for cold end heat exchange, and a second outlet for cold end heat exchange. The liquid air storage tank is provided with a liquid air inlet and a liquid air outlet. The distillation air compressor is equipped with a set of inlets and outlets, namely a distillation air inlet and a distillation air outlet; The distillation nitrogen water precooling system is equipped with a condensate discharge port and a set of inlets and outlets, which are respectively a cooling air inlet and a cooling air outlet. The distillation molecular sieve is provided with two sets of inlets and outlets, namely, a distillation purified air inlet and a distillation purified air outlet, a distillation waste nitrogen inlet and a distillation waste nitrogen outlet; The main heat exchanger is provided with four sets of inlets and outlets, namely, heat exchange first inlet, heat exchange first outlet, heat exchange second outlet, heat exchange second inlet, heat exchange third outlet, heat exchange third inlet, heat exchange fourth outlet, and heat exchange fourth inlet; The distillation column is equipped with a compressed air inlet, a lower column liquid air inlet, a lower column medium-pressure nitrogen outlet, a lower column nitrogen outlet, a main column condenser / evaporator nitrogen inlet, a main column condenser / evaporator liquid nitrogen outlet, an upper column liquid nitrogen inlet, an upper column waste nitrogen outlet, an upper column nitrogen outlet, an upper column oxygen outlet, an upper column argon fraction outlet, an upper column crude liquid argon inlet, an upper column liquid air inlet, an upper column liquid air vapor inlet, an upper column liquid air reflux port, an upper column liquid oxygen outlet, and a lower column liquid air outlet. The distillation subcooler is provided with five sets of inlets and outlets, namely the first distillation subcooling inlet, the first distillation subcooling outlet, the second distillation subcooling inlet, the second distillation subcooling outlet, the third distillation subcooling inlet, the third distillation subcooling outlet, the fourth distillation subcooling inlet, the fourth distillation subcooling outlet, the fifth distillation subcooling inlet, and the fifth distillation subcooling outlet. The crude argon column is equipped with an argon fraction inlet, a crude liquid argon outlet, a crude argon gas outlet, an argon gas inlet for the crude argon column condenser-evaporator, a crude liquid argon outlet for the crude argon column condenser-evaporator, a crude liquid argon purification outlet, a crude argon column liquid air inlet, a crude argon column liquid air outlet, and a crude argon column liquid air vapor outlet. The refined argon tower is equipped with a crude liquid argon inlet, a liquid argon outlet, an argon gas outlet, an argon gas inlet for the condenser / evaporator, a liquid argon outlet for the condenser / evaporator, a non-condensable gas outlet, a medium-pressure nitrogen inlet for the condenser / evaporator, a liquid nitrogen outlet for the condenser / evaporator, a liquid nitrogen inlet for the condenser / evaporator, and a nitrogen outlet for the argon tower. The liquefied air inlet is connected to the atmosphere, and the liquefied air outlet, precooled air inlet, precooled air outlet, and liquefied purified air inlet are connected in series in sequence; the cold end pressurized air inlet, cold end pressurized air outlet, cold end air inlet, cold end air outlet, hot end pressurized air inlet, hot end pressurized air outlet, hot end air inlet, hot end air outlet, and hot end heat exchange first inlet are connected in series in sequence. The second outlet of the hot end heat exchange is connected to the air inlet of the cold end expansion end; the air outlet of the cold end expansion end and the second outlet of the cold end heat exchange merge and are then connected to the third inlet of the hot end heat exchange; the third outlet of the hot end heat exchange merges with the liquefied purified air outlet and is then connected to the circulating air inlet. The circulating air outlet is divided into two streams, which are respectively connected to the second inlet of the hot end heat exchange and the air inlet of the cold end pressurization end; the first outlet of the hot end heat exchange is divided into two streams, which are respectively connected to the air inlet of the hot end expansion end and the first inlet of the cold end heat exchange; the air outlet of the hot end expansion end is connected to the second inlet of the cold end heat exchange; the first outlet of the cold end heat exchange is connected to the liquid air inlet of the storage tank; The distillation air inlet is connected to the atmosphere, and the distillation air outlet, cooling air inlet, cooling air outlet, distillation purified air inlet, distillation purified air outlet, first heat exchange inlet, first heat exchange outlet, and compressed air inlet are connected in series in sequence; the storage tank liquid air outlet is connected to the lower tower liquid air inlet; The lower column nitrogen outlet, the main column condenser evaporator nitrogen inlet, the main column condenser evaporator liquid nitrogen outlet, and the first distillation subcooling inlet are connected in series in sequence; the first distillation subcooling outlet is divided into three streams, which are respectively connected to the upper column liquid nitrogen inlet, the argon column liquid nitrogen inlet, and the liquid nitrogen storage tank. The medium-pressure nitrogen outlet of the lower tower, the medium-pressure nitrogen inlet of the argon tower condenser-evaporator, the liquid nitrogen outlet of the argon tower condenser-evaporator, and the liquid nitrogen inlet of the argon tower are connected in series sequentially. The waste nitrogen outlet of the upper column and the nitrogen outlet of the refined argon column are merged and then connected to the third inlet of the distillation subcooler; the third outlet of the distillation subcooler is connected to the fourth inlet of the heat exchanger; the fourth outlet of the heat exchanger is divided into three streams, one stream is directly connected to the atmosphere, and the other two streams are respectively connected to the liquefied waste nitrogen inlet and the distillation waste nitrogen inlet; both the liquefied waste nitrogen outlet and the distillation waste nitrogen outlet are connected to the atmosphere; The upper column nitrogen outlet, the fourth distillation subcooling inlet, the fourth distillation subcooling outlet, and the third heat exchange inlet are connected in series in sequence, and the third heat exchange outlet is connected to the user's nitrogen pipeline network. The upper column oxygen outlet and the fifth distillation subcooling inlet are connected in series; the fifth distillation subcooling outlet and the second heat exchange inlet are connected in series; the second heat exchange outlet is connected to the user's oxygen pipeline network. The argon fraction outlet of the upper column is connected to the argon fraction inlet; The crude liquid argon outlet is connected to the crude liquid argon inlet of the upper tower; The crude argon tower liquid air vapor outlet is connected to the upper tower liquid air vapor inlet; The liquid air outlet of the crude argon tower is connected to the liquid air reflux port of the upper tower. The liquid oxygen outlet of the upper tower is connected to the liquid oxygen storage tank; The lower column liquid air outlet is connected to the second subcooling inlet of the distillation column; the second subcooling outlet of the distillation column is divided into two streams, which are respectively connected to the upper column liquid air inlet and the crude argon column liquid air inlet. The crude argon outlet is connected to the argon inlet of the crude argon tower condenser-evaporator, and the crude liquid argon purification outlet is connected to the crude liquid argon inlet of the refined argon tower; the crude liquid argon outlet of the crude argon tower condenser-evaporator is refluxed into the crude argon tower. The argon outlet of the argon tower is connected to the argon inlet of the argon tower condenser / evaporator; the liquid argon outlet of the argon tower condenser / evaporator is refluxed into the argon tower; and the non-condensable gas outlet is connected to the atmosphere. The liquid argon outlet of the argon refiner is connected to the liquid argon storage tank.

[0007] Furthermore, the air liquefaction system also includes a subcooled expander; a subcooled end cooler; and a liquefaction subcooler. The liquid air storage tank is provided with a compressed air inlet; the subcooled expander is provided with two sets of inlets and outlets, namely a subcooled booster air inlet, a subcooled booster air outlet, a subcooled expansion air inlet, and a subcooled expansion air outlet; the subcooled end cooler is provided with one set of inlets and outlets, namely a subcooled end air inlet and a subcooled end air outlet; the liquefaction subcooler is provided with two sets of inlets and outlets, namely a first liquefaction subcooling inlet, a first liquefaction subcooling outlet, a second liquefaction subcooling inlet, and a second liquefaction subcooling outlet; The hot-end heat exchanger is also provided with two sets of inlets and outlets, namely the fourth inlet of hot-end heat exchange, the fourth outlet of hot-end heat exchange, the fifth inlet of hot-end heat exchange, and the fifth outlet of hot-end heat exchange; the cold-end heat exchanger is also provided with two sets of inlets and outlets, namely the third inlet of cold-end heat exchange, the third outlet of cold-end heat exchange, the fourth inlet of cold-end heat exchange, and the fourth outlet of cold-end heat exchange. The third outlet of the hot end heat exchange is divided into two streams. One stream is connected to the circulating air inlet, and the other stream is connected to the subcooled pressurized end air inlet. The subcooled pressurized end air outlet, the subcooled end air inlet, the subcooled end air outlet, the third inlet of the cold end heat exchange, the third outlet of the cold end heat exchange, the fourth inlet of the hot end heat exchange, the fourth outlet of the hot end heat exchange, the third inlet of the cold end heat exchange, the third outlet of the cold end heat exchange, the subcooled expansion end air inlet, the subcooled expansion end air outlet, the second inlet of the liquefied subcooling, the second outlet of the liquefied subcooling, the fourth inlet of the cold end heat exchange, the fourth outlet of the cold end heat exchange, the fifth inlet of the hot end heat exchange, and the liquefied waste nitrogen inlet are connected in series. The cold end heat exchange first outlet, the liquefaction subcooling first inlet, the liquefaction subcooling first outlet, and the storage tank liquid air inlet are connected in series in sequence. The first heat exchange outlet is divided into two streams: one stream is connected to the compressed air inlet of the distillation column, and the other stream is connected to the compressed air inlet of the liquid air storage tank.

[0008] Furthermore, the first outlet of the distillation subcooling is connected to the liquid nitrogen inlet of the upper column after passing through a throttle valve and a U-tube in sequence, and a branch is split at the U-tube to connect to the liquid nitrogen storage tank.

[0009] Furthermore, the liquefied feedstock air compressor, the air separation feedstock air compressor, and the circulating compressor are all centrifugal air compressors, equipped with a frequency converter start-up device for smooth start-up and load adjustment.

[0010] Furthermore, the liquid air storage tank is a non-self-pressurized storage tank. The pressure difference is provided by the compressed air generated by the distillation feed air compressor to send the liquid air in the storage tank to the column for distillation.

[0011] Furthermore, the liquid air storage tank is a pressure storage tank.

[0012] Furthermore, the liquid air storage tank is also equipped with an external liquid air inlet for inputting low-cost external liquid air, thereby optimizing economic efficiency.

[0013] The air liquefaction system and the air distillation system operate independently but are coupled together via a liquid air storage tank. The air liquefaction system and the air distillation system operate at different times or simultaneously. The air liquefaction system can operate intermittently at night, utilizing off-peak electricity to produce liquid air, while the air distillation system operates continuously, reducing overall energy consumption.

[0014] The beneficial effects of this utility model are as follows: 1. Effectively reduces equipment operating energy consumption. In conventional all-liquid air separation, liquefaction refrigeration energy consumption accounts for approximately 65% ​​of the total energy consumption. However, air-refrigerated liquefaction and air distillation are independent processes, allowing the air distillation system to operate continuously 24 hours a day, achieving high efficiency in air separation distillation. It also allows the use of low-cost external liquid air, reducing equipment costs. The air-refrigerated liquefaction system operates in shifts, taking advantage of lower electricity prices at night to reduce liquefaction costs. Ultimately, the two systems are matched, significantly reducing operating costs. The buffering effect of the liquid air storage tank reduces gas venting, saving energy and raw materials.

[0015] 2. Maintaining the efficiency of the air separation and distillation system. Liquid air can be started and stopped in just half an hour, which is faster than air separation, avoiding the risk of stress changes within the column and even leaks caused by frequent start-ups and shutdowns in the air separation system. Conventional air separation operation takes about 3 hours to establish, and argon column operation takes about 30 hours. This invention shortens the establishment time, thereby improving efficiency and maximizing liquid argon production capacity. Three expanders are used in the air-cooled liquefaction system. Compared with the traditional process, the addition of subcooled expanders increases the liquid air production capacity.

[0016] 3. Significantly improved operational flexibility and stability. An independent liquid air production system, equipped with liquid air storage tanks, can absorb fluctuations in the upstream system, providing the distillation column with feedstock of stable flow rate and composition. This makes the distillation column operation very stable, and product quality easier to control. The molecular sieve desorbed gas utilizes low-pressure air generated by its own air-cooled liquefaction unit, further enhancing stability.

[0017] 4. Enhanced Capability to Cope with Variable Loads (Adapting to Market Demand Fluctuations). When increased liquid oxygen production is needed, more liquid air can be drawn from the liquid air storage tank and fed into the distillation column, achieving rapid production increases without waiting for the slow response of the air compressor and cooling system. During periods of low demand, the liquid air production system can maintain a lower but more efficient operating load, storing excess liquid air. Alternatively, the operating time of the air refrigeration liquefaction system can be shortened to reduce liquid air production, consuming the inventory in the storage tank, while the distillation column can still maintain a higher operating load. This "peak shaving and valley filling" capability significantly improves the overall economics of the plant. The liquid air storage tank has an external liquid air inlet interface for low-cost liquid air input, further adapting to the market.

[0018] 5. Convenient start-up and rapid restart. With an independent liquid air production and storage system, after a short-term shutdown, the existing liquid air in the storage tank can be used to quickly establish liquid circulation and distillation conditions within the distillation column, significantly shortening restart time and saving substantial energy and costs. The liquid air storage tank is not a self-pressurizing tank; it uses compressed air to provide a pressure difference, avoiding energy loss.

[0019] 6. Enhanced safety. When one system fails (e.g., the purification system requires maintenance), it can be isolated, while another system, supported by existing inventory, may still be able to maintain operation for a short period or be safely shut down. The air compressor and circulating unit are equipped with variable frequency drives and are centrifugal air compressors, ensuring smooth startup.

[0020] 7. Improved Energy Efficiency and Economic Benefits. Air compressors and expanders are most efficient under specific design conditions. Independent design allows the liquid air production system (main heat exchanger, expander, etc.) to operate at its optimal pressure without having to completely accommodate the pressure requirements of the distillation column. During load fluctuations, the buffer provided by the storage tank minimizes gas venting, directly saving energy and raw materials. This unit can produce liquid air continuously and effectively utilize off-peak electricity to produce liquid products.

[0021] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the all-liquid air separation device with independent air refrigeration liquefaction and air separation distillation phases in Embodiment 1 of this utility model.

[0023] Figure 2 This is a schematic diagram of the all-liquid air separation device with independent air refrigeration liquefaction and air separation distillation phases in Embodiment 2 of this utility model.

[0024] Reference numerals: 101 - Liquefied air compressor; 1011 - Liquefied air inlet; 1012 - Liquefied air outlet; 102-Liquefied air dryer; 1021-Pre-cooled air inlet; 1022-Pre-cooled air outlet; 1023-Condensate drain outlet; 103-Liquefied molecular sieve; 1031-Liquefied purified air inlet; 1032-Liquefied purified air outlet; 1033-Liquefied waste nitrogen inlet; 1034-Liquefied waste nitrogen outlet; 104 - Subcooled expander; 1041 - Subcooled booster air inlet; 1042 - Subcooled booster air outlet; 1043 - Subcooled expansion air inlet; 1044 - Subcooled expansion air outlet; 105 - Subcooled end cooler; 1051 - Subcooled end air inlet; 1052 - Subcooled end air outlet; 106 - Circulating air unit; 1061 - Circulating air inlet; 1062 - Circulating air outlet; 107-Cold end expander; 1071-Cold end pressurization air inlet; 1072-Cold end pressurization air outlet; 1073-Cold end expansion air inlet; 1074-Cold end expansion air outlet; 108 - Cold end cooler; 1081 - Cold end air inlet; 1082 - Cold end air outlet; 109-Hot end expander; 1091-Hot end pressurization air inlet; 1092-Hot end pressurization air outlet; 1093-Hot end expansion air inlet; 1094-Hot end expansion air outlet; 110 - Hot-end cooler; 1101 - Hot-end air inlet; 1102 - Hot-end air outlet; 111-Hot end heat exchanger; 1111-Hot end heat exchanger first inlet; 1112-Hot end heat exchanger first outlet; 1113-Hot end heat exchanger second inlet; 1114-Hot end heat exchanger second outlet; 1115-Hot end heat exchanger third inlet; 1116-Hot end heat exchanger third outlet; 1117-Hot end heat exchanger fourth inlet; 1118-Hot end heat exchanger fourth outlet; 1119-Hot end heat exchanger fifth inlet; 1111*-Hot end heat exchanger fifth outlet; 112 - Cold end heat exchanger; 1121 - First inlet for cold end heat exchange; 1122 - First outlet for cold end heat exchange; 1123 - Second inlet for cold end heat exchange; 1124 - Second outlet for cold end heat exchange; 1125 - Third inlet for cold end heat exchange; 1126 - Third outlet for cold end heat exchange; 1127 - Fourth inlet for cold end heat exchange; 1128 - Fourth outlet for cold end heat exchange; 113 - Liquefaction subcooler; 1131 - First inlet of liquefaction subcooler; 1132 - First outlet of liquefaction subcooler; 1133 - Second inlet of liquefaction subcooler; 1134 - Second outlet of liquefaction subcooler; 114-Liquid air storage tank; 1141-Liquid air inlet of storage tank; 1142-Liquid air outlet of storage tank; 1143-External liquid air inlet; 1144-Compressed air inlet of liquid air storage tank; 201 - Distillation air compressor; 2011 - Distillation air inlet; 2012 - Distillation air outlet; 202 - Distillation nitrogen-water precooling system; 2021 - Cooling air inlet; 2022 - Cooling air outlet; 2023 - Condensate discharge port of the distillation nitrogen-water precooling system; 203 - Distillation molecular sieve; 2031 - Distillation purified air inlet; 2032 - Distillation purified air outlet; 2033 - Distillation waste nitrogen inlet; 2034 - Distillation waste nitrogen outlet; 204 - Main heat exchanger; 2041 - First heat exchange inlet; 2042 - First heat exchange outlet; 2043 - Second heat exchange outlet; 2044 - Second heat exchange inlet; 2045 - Third heat exchange outlet; 2046 - Third heat exchange inlet; 2047 - Fourth heat exchange outlet; 2048 - Fourth heat exchange inlet; 205 - Distillation column; 2051 - Compressed air inlet; 2052 - Lower column liquid air inlet; 2053 - Lower column medium-pressure nitrogen outlet; 2054 - Lower column nitrogen outlet; 2055 - Main column condenser / evaporator nitrogen inlet; 2056 - Main column condenser / evaporator liquid nitrogen outlet; 2057 - Upper column liquid nitrogen inlet; 2058 - Upper column waste nitrogen outlet; 2059 - Upper column nitrogen outlet; 2051* - Upper column oxygen outlet; 2052* - Upper column argon fraction outlet; 2053* - Upper column crude liquid argon inlet; 2054* - Upper column liquid air inlet; 2055* - Upper column liquid air vapor inlet; 2056* - Upper column liquid air reflux port; 2057* - Upper column liquid oxygen outlet; 2058* - Lower column liquid air outlet; 206 - Distillation subcooler; 2061 - First inlet of distillation subcooler; 2062 - First outlet of distillation subcooler; 2063 - Second inlet of distillation subcooler; 2064 - Second outlet of distillation subcooler; 2065 - Third inlet of distillation subcooler; 2066 - Third outlet of distillation subcooler; 2067 - Fourth inlet of distillation subcooler; 2068 - Fourth outlet of distillation subcooler; 2069 - Fifth inlet of distillation subcooler; 2061* - Fifth outlet of distillation subcooler; 207 - Crude argon column; 2071 - Argon fraction inlet; 2072 - Crude liquid argon outlet; 2073 - Crude argon gas outlet; 2074 - Argon gas inlet of crude argon column condenser / evaporator; 2075 - Crude liquid argon outlet of crude argon column condenser / evaporator; 2076 - Crude liquid argon purification outlet; 2077 - Crude argon column liquid air inlet; 2078 - Crude argon column liquid air outlet; 2079 - Crude argon column liquid air vapor outlet; 208 - Refined argon tower; 2081 - Refined argon tower crude liquid argon inlet; 2082 - Refined argon tower liquid argon outlet; 2083 - Refined argon tower argon outlet; 2084 - Refined argon tower condenser / evaporator argon inlet; 2085 - Refined argon tower condenser / evaporator liquid argon outlet; 2086 - Non-condensable gas outlet; 2087 - Refined argon tower condenser / evaporator medium-pressure nitrogen inlet; 2088 - Refined argon tower condenser / evaporator liquid nitrogen outlet; 2089 - Refined argon tower liquid nitrogen inlet; 2081* - Refined argon tower nitrogen outlet. Detailed Implementation

[0025] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this utility model. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0027] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0028] Example 1 Please see Figure 1 This is a fully liquid air separation unit with independent air refrigeration liquefaction and air separation distillation phases, comprising a liquefied air compressor 101; a liquefied refrigerated dryer 102; a liquefied molecular sieve 103; a circulator 106; a cold-end expander 107; a cold-end cooler 108; a hot-end expander 109; a hot-end cooler 110; a hot-end heat exchanger 111; a cold-end heat exchanger 112; a liquid air storage tank 114; a distillation air compressor 201; a distillation nitrogen-water precooling system 202; a distillation molecular sieve 203; a main heat exchanger 204; a distillation column 205; a distillation subcooler 206; a crude argon column 207; and a refined argon column 208.

[0029] The liquefied air compressor 101 has a set of inlets and outlets, namely liquefied air inlet 1011 and liquefied air outlet 1012; the distillation air compressor 201 has a set of inlets and outlets, namely distillation air inlet 2011 and distillation air outlet 2012; the circulating air compressor 106 has a set of inlets and outlets, namely circulating air inlet 1061 and circulating air outlet 1062; the liquefied refrigerated dryer 102 has a condensate drain outlet 1023 and a set of inlets and outlets, namely pre-cooled air inlet 1021 and pre-cooled air outlet 1022; the liquefied molecular sieve 103 has two sets of inlets and outlets, namely liquefied purified air inlet 1031 and liquefied purified air outlet 1032, and liquefied waste nitrogen outlet 1032. Inlet 1033, liquefied waste nitrogen outlet 1034; the distillation nitrogen water precooling system 202 is equipped with a distillation nitrogen water precooling system condensate discharge port 2023 and a set of inlets and outlets, which are cooling air inlet 2021 and cooling air outlet 2022 respectively; the distillation molecular sieve 203 is equipped with two sets of inlets and outlets, namely distillation purified air inlet 2031, distillation purified air outlet 2032, distillation waste nitrogen inlet 2033, and distillation waste nitrogen outlet 2034; the cold end expander 107 is equipped with two sets of inlets and outlets, namely cold end pressurization end air inlet 1071, cold end pressurization end air outlet 1072, cold end expansion end air inlet 1073, and cold end expansion end air outlet 1074; cold end cooling The heat exchanger 108 has one set of inlets and outlets: a cold-end air inlet 1081 and a cold-end air outlet 1082. The hot-end expander 109 has two sets of inlets and outlets: a hot-end pressurization air inlet 1091, a hot-end pressurization air outlet 1092, a hot-end expansion air inlet 1093, and a hot-end expansion air outlet 1094. The hot-end cooler 110 has one set of inlets and outlets: a hot-end air inlet 1101 and a hot-end air outlet 1102. The hot-end heat exchanger 111 has three sets of inlets and outlets: a first hot-end heat exchange inlet 1111, a first hot-end heat exchange outlet 1112, a second hot-end heat exchange inlet 1113, a second hot-end heat exchange outlet 1114, and a third hot-end heat exchange outlet 1115. 15. The third outlet of the hot-end heat exchanger is 1116; the cold-end heat exchanger 112 is provided with two sets of inlets and outlets, namely the first inlet of the cold-end heat exchanger 1121, the first outlet of the cold-end heat exchanger 1122, the second inlet of the cold-end heat exchanger 1123, and the second outlet of the cold-end heat exchanger 1124; the liquid-air storage tank 114 is provided with the tank liquid-air inlet 1141, the tank liquid-air outlet 1142, and the external liquid-air inlet 1143; the main heat exchanger 204 is provided with four sets of inlets and outlets, namely the first inlet of the heat exchanger 2041, the first outlet of the heat exchanger 2042, the second inlet of the heat exchanger 2043, the second outlet of the heat exchanger 2044, the third inlet of the heat exchanger 2045, the third outlet of the heat exchanger 2046, the fourth inlet of the heat exchanger 2047, and the fourth outlet of the heat exchanger 2048;The distillation subcooler 206 is equipped with five sets of inlets and outlets: first inlet 2061, first outlet 2062, second inlet 2063, second outlet 2064, third inlet 2065, third outlet 2066, fourth inlet 2067, fourth outlet 2068, fifth inlet 2069, and fifth outlet 2061*; the distillation column 205 is equipped with a compressed air inlet. 2051, Lower column liquid air inlet; 2052, Lower column medium-pressure nitrogen outlet; 2053, Lower column nitrogen outlet; 2054, Main column condenser / evaporator nitrogen inlet; 2055, Main column condenser / evaporator liquid nitrogen outlet; 2056, Upper column liquid nitrogen inlet; 2057, Upper column waste nitrogen outlet; 2058, Upper column nitrogen outlet; 2059, Upper column oxygen outlet; 2051*, Upper column liquid oxygen outlet; 2057*, Lower column liquid air outlet; 2058*, Upper column liquid air inlet; 2054*, Upper column argon fraction outlet; 2052 * Upper column crude liquid argon inlet 2053*, upper column liquid air outlet 2054*, upper column liquid air reflux inlet 2055*, upper column liquid air vapor inlet 2056*; Crude argon column 207 is equipped with argon fraction inlet 2071, crude liquid argon outlet 2072, crude argon gas outlet 2073, crude argon column condenser evaporator argon gas inlet 2074, crude argon column condenser evaporator crude liquid argon outlet 2075, crude liquid argon purification outlet 2076, crude argon column liquid air inlet 2077, and crude argon column liquid air outlet 2078. The crude argon column has a liquid air vapor outlet at 2079; the refined argon column 208 is equipped with a crude liquid argon inlet at 2081, a liquid argon outlet at 2082, an argon outlet at 2083, an argon inlet to the condenser / evaporator at 2084, a liquid argon outlet at 2085, a non-condensable gas outlet at 2086, a medium-pressure nitrogen inlet to the condenser / evaporator at 2087, a liquid nitrogen outlet at 2088, a liquid nitrogen inlet at 2089, and a nitrogen outlet at 2081*.

[0030] The liquefied air compressor 101 has its liquefied air inlet 1011 connected to the atmosphere, and its liquefied air outlet 1012 connected to the pre-cooled air inlet 1021 of the liquefied air dryer 102, used to compress atmospheric air and send it to the liquefied air dryer for cooling and dehydration. The pre-cooled air outlet 1022 of the liquefied air dryer 102 is connected to the liquefied purified air inlet 1031 of the liquefied molecular sieve 103, used to deliver the cooled air to the liquefied molecular sieve for purification and impurity removal. The condensate drain outlet 1023 of the liquefied air dryer 102 is connected to a drainage system for discharging condensate generated during the cooling process. The liquefied purified air outlet 1032 of the liquefied molecular sieve 103 is connected to the circulating air inlet 1061 of the circulator 106, used to provide purified air for further purification. The air exchange process involves compression and circulation. The circulating air outlet 1062 of the circulating unit 106 is connected to the second hot-end heat exchange inlet 1113 of the hot-end heat exchanger 111. The second hot-end heat exchange outlet 1114 of the hot-end heat exchanger 111 is connected to the cold-end expansion air inlet 1073 of the cold-end expander 107. The cold-end expansion air outlet 1074 of the cold-end expander 107 merges with the second cold-end heat exchange outlet 1124 of the cold-end heat exchanger 112 and then connects to the third hot-end heat exchange inlet 1115 of the hot-end heat exchanger 111. The third hot-end heat exchange outlet 1116 of the hot-end heat exchanger 111 merges with the liquefied purified air outlet 1032 and then connects to the circulating air inlet 1061. The circulating air outlet 1062 splits into two streams, each connecting to the second hot-end heat exchange inlet 1061. The cold end air inlet 1071 of the cold end expander 107 is connected to the cold end air inlet 1091 of the hot end expander 109 after being cooled by the cold end cooler 108; the hot end air outlet 1092 of the hot end expander 109 is connected to the hot end air inlet 1091 of the hot end expander 109 after being cooled by the hot end cooler 110; the hot end heat exchange first outlet 1112 of the hot end heat exchanger 111 is divided into two streams, which are connected to the hot end expansion air inlet 1093 and the cold end heat exchange first inlet 1121, respectively; the hot end expansion air outlet 1094 of the hot end expander 109 is connected to the cold end heat exchange second inlet 1123 of the cold end heat exchanger 112. The first cold-end heat exchange outlet 1122 of the cold-end heat exchanger 112 is connected to the liquid air inlet 1141 of the liquid air storage tank 114; the liquefied waste nitrogen inlet 1033 of the liquefied molecular sieve 103 is connected to the third hot-end heat exchange outlet 1116 of the hot-end heat exchanger 111, and its liquefied waste nitrogen outlet 1034 is connected to the atmosphere for discharging the regenerated waste nitrogen; the cold-end air inlet 1081 of the cold-end cooler 108 is connected to the cold-end pressurized air outlet 1072, and its cold-end air outlet 1082 is connected to the hot-end pressurized air inlet 1091; the hot-end air inlet 1101 of the hot-end cooler 110 is connected to the hot-end pressurized air outlet 1092, and its hot-end air outlet 1102 is connected to the first hot-end heat exchange inlet 1111.

[0031] The distillation air inlet 2011 of the distillation air compressor 201 is connected to the atmosphere, and the distillation air outlet 2012 is connected to the cooling air inlet 2021 of the distillation nitrogen-water precooling system 202, where the air is cooled, and the generated cooling water is discharged through the condensate outlet 2023 of the distillation nitrogen-water precooling system; the cooling air outlet 2022 of the distillation nitrogen-water precooling system 202 is connected to the distillation purified air inlet 2031 of the distillation molecular sieve 203; the distillation purified air outlet 2032 of the distillation molecular sieve 203 is connected to the first heat exchange inlet 2041 of the main heat exchanger 204; the first heat exchange outlet 2042 of the main heat exchanger 204 is connected to the compressed air inlet 2051 of the distillation column 205; the liquid air outlet 1142 of the liquid air storage tank 114 is connected to the compressed air outlet 2051 of the distillation column 205; The lower column liquid air inlet 2052 of distillation column 205 is connected; the lower column nitrogen outlet 2054 of distillation column 205 is connected to the nitrogen inlet 2055 of the main column condenser-evaporator; the liquid nitrogen outlet 2056 of the main column condenser-evaporator is connected to the first subcooling inlet 2061 of the subcooling unit 206; the first subcooling outlet 2062 of the subcooling unit 206 is connected to the upper column liquid nitrogen inlet 2057 of distillation column 205 after passing through a throttle valve and a U-tube, and a branch is diverted at the U-tube as the product liquid nitrogen output connected to the liquid nitrogen storage tank; the upper column oxygen outlet 2051 of distillation column 205 is connected to the fifth subcooling inlet 2069 of the subcooling unit 206; the fifth subcooling outlet 2061 of the subcooling unit 206 is connected to the second heat exchange inlet of the main heat exchanger 204. Oxygen is connected to the user's oxygen pipeline network via the second heat exchange outlet 2044 of the main heat exchanger 204; the lower column liquid air outlet 2058 of the distillation column 205 is connected to the second distillation subcooling inlet 2063 of the distillation subcooler 206; the second distillation subcooling outlet 2064 of the distillation subcooler 206 is divided into two streams, which are connected to the upper column liquid air inlet 2054 of the distillation column 205 and the crude argon column liquid air inlet 2077 of the crude argon column 207, respectively; the upper column waste nitrogen outlet 2058 of the distillation column 205 and the refined argon column nitrogen outlet 2081 of the refined argon column 208 merge and are connected to the third distillation subcooling inlet 2065 of the distillation subcooler 206; the third distillation subcooling outlet 2066 of the distillation subcooler 206 is connected to the fourth heat exchange inlet of the main heat exchanger 204. The main heat exchanger 204's fourth heat exchange outlet 2048 is divided into three streams: one stream is directly connected to the atmosphere, and the other two streams are respectively connected to the liquefied waste nitrogen inlet 1033 of the liquefied molecular sieve 103 and the rectification waste nitrogen inlet 2033 of the rectification molecular sieve 203; the liquefied waste nitrogen outlet 1034 of the liquefied molecular sieve 103 and the rectification waste nitrogen outlet 2034 of the rectification molecular sieve 203 are both connected to the atmosphere; the upper column nitrogen outlet 2059 of the distillation column 205 is connected to the fourth rectification subcooling inlet 2067 of the rectification subcooler 206; the fourth rectification subcooling outlet 2068 of the rectification subcooler 206 is connected to the third heat exchange inlet 2045 of the main heat exchanger 204; the third heat exchange outlet 2046 of the main heat exchanger 204 is connected to the user's nitrogen pipeline network;The upper argon fraction outlet 2052 of distillation column 205 is connected to the argon fraction inlet 2071 of crude argon column 207; the crude liquid argon outlet 2072 of crude argon column 207 is connected to the upper crude liquid argon inlet 2053 of distillation column 205; the crude argon column liquid air vapor outlet 2079 of crude argon column 207 is connected to the upper liquid air vapor inlet 2056 of distillation column 205; the crude argon column liquid air outlet 2078 of crude argon column 207 is connected to... The upper liquid air reflux port 2055 of distillation column 205 is connected; the upper liquid oxygen outlet 2057 of distillation column 205 is connected to the liquid oxygen storage tank; the crude argon outlet 2073 of crude argon column 207 is connected to the argon inlet 2074 of the crude argon column condenser / evaporator; the crude liquid argon outlet 2076 of crude argon column 207 is connected to the crude liquid argon inlet 2081 of the refined argon column 208; the crude argon column condenser / evaporator of crude argon column 207... The crude liquid argon outlet 2075 is refluxed into the crude argon column 207; the medium-pressure nitrogen outlet 2053 of the lower column of the distillation column 205 is connected to the medium-pressure nitrogen inlet 2087 of the condenser / evaporator of the argon column 208; the liquid nitrogen outlet 2088 of the condenser / evaporator of the argon column 208 is connected to the liquid nitrogen inlet 2089 of the argon column 208; the argon outlet 2083 of the argon column 208 is connected to the condenser / evaporator of the argon column 208. The evaporator argon inlet 2084 is connected; the liquid argon outlet 2085 of the condenser evaporator in the argon column 208 is refluxed into the argon column 208; the non-condensable gas outlet 2086 of the argon column 208 is connected to the atmosphere; the liquid argon outlet 2082 of the argon column 208 is connected to the liquid argon storage tank; the first subcooling outlet 2062 of the distillation subcooler 206 is connected to the liquid nitrogen inlet 2089 of the argon column 208.

[0032] The air is pressurized to 0.54 MPa by a liquefied raw material air compressor (connected to a DN80 pipe). After compression, it is sent to the hot-end heat exchanger 111, where the pressure at the junction is approximately 0.72 MPa (connected to a DN40 pipe). It is then sent to the cold-end heat exchanger 112, where the pressure at the junction is also approximately 0.72 MPa (connected to a DN40 pipe). The air from the circulating unit outlet is compressed and sent back to the hot-end heat exchanger 111, where the pressure at the junction is approximately 0.64 MPa.

[0033] The raw materials used in this embodiment are: atmospheric pressure air: 30000 Nm³ / h, 98 kPa.

[0034] The products obtained are: liquid air: 13500 Nm³ / h (converted to gaseous state); liquid oxygen: 4000 Nm³ / h; liquid nitrogen: 1200 Nm³ / h; liquid argon: 115 Nm³ / h.

[0035] Example 2 Please see Figure 2This is a fully liquid air separation device where air refrigeration liquefaction and air separation distillation are independent. Unlike Example 1, the air liquefaction system in this example also includes a subcooled expander 104; a subcooled end cooler 105; a liquefaction subcooler 113; and a liquid air storage tank 114 with a liquid air storage tank compressed air inlet 1144.

[0036] The subcooled expander 104 has two sets of inlets and outlets: a subcooled booster air inlet 1041, a subcooled booster air outlet 1042, a subcooled expansion air inlet 1043, and a subcooled expansion air outlet 1044. The subcooled end cooler 105 has one set of inlets and outlets: a subcooled end air inlet 1051 and a subcooled end air outlet 1052. The liquefaction subcooler 113 has two sets of inlets and outlets: a first liquefaction subcooling inlet 1131, a first liquefaction subcooling outlet 1132, and a second liquefaction subcooling outlet 1044. The heat exchanger 111 has a second cold inlet 1133 and a second liquefied subcooling outlet 1134. The hot-end heat exchanger 111 is also provided with two sets of inlets and outlets, namely the fourth hot-end heat exchange inlet 1117, the fourth hot-end heat exchange outlet 1118, the fifth hot-end heat exchange inlet 1119, and the fifth hot-end heat exchange outlet 1111*. The cold-end heat exchanger 112 is also provided with two sets of inlets and outlets, namely the third cold-end heat exchange inlet 1125, the third cold-end heat exchange outlet 1126, the fourth cold-end heat exchange inlet 1127, and the fourth cold-end heat exchange outlet 1128.

[0037] The third outlet 1116 of the hot-end heat exchanger 111 is divided into two streams. One stream connects to the circulating air inlet 1061 of the circulating machine 106, and the other stream connects to the subcooled booster air inlet 1041 of the subcooled expander 104. The subcooled booster air outlet 1042 of the subcooled expander 104, the subcooled air inlet 1051 and subcooled air outlet 1052 of the subcooled cooler 105, the third inlet 1125 and third outlet 1126 of the cold-end heat exchanger 112, the fourth inlet 1117 and fourth outlet 1118 of the hot-end heat exchanger 111, the third inlet 1125 and third outlet 1126 of the cold-end heat exchanger 112, the subcooled expansion air inlet 1043 and subcooled expansion air outlet 1044 of the subcooled expander 104, and the liquefied subcooler... The liquefied subcooling second inlet 1133 and liquefied subcooling second outlet 1134 of the liquefied subcooling unit 113, the cold-end heat exchange fourth inlet 1127 and cold-end heat exchange fourth outlet 1128 of the cold-end heat exchanger 112, the hot-end heat exchange fifth inlet 1119 and hot-end heat exchange fifth outlet 1111* of the hot-end heat exchanger 111, and the liquefied waste nitrogen inlet 1033 of the liquefied molecular sieve 103 are connected in series; the cold-end heat exchanger 112... The first outlet 1122, the first liquefaction subcooling inlet 1131 of the liquefaction subcooler 113, the first liquefaction subcooling outlet 1132, and the liquid air inlet 1141 of the liquid air storage tank 114 are connected in series in sequence; the first heat exchange outlet 2042 of the main heat exchanger 204 is divided into two streams, one stream is connected to the compressed air inlet 2051 of the distillation column 205, and the other stream is connected to the compressed air inlet 1144 of the liquid air storage tank 114.

[0038] The connection of the air distillation system is the same as in Example 1.

[0039] The process involves pressing air to 0.54 MPa using a liquefied feedstock air compressor (connected to a DN80 pipe). After compression, the air is sent to the hot-end heat exchanger 111, where the pressure at the junction point is approximately 0.72 MPa (connected to a DN40 pipe). It is then sent to the cold-end heat exchanger 112, again at approximately 0.72 MPa (connected to a DN40 pipe). After expansion, the air is sent to the liquefied subcooler 113, where the pressure at the junction point is approximately 0.13 MPa (connected to a DN40 pipe). Finally, the air from the circulating unit outlet is compressed and sent back to the hot-end heat exchanger 111, where the pressure at the junction point is approximately 0.64 MPa.

[0040] The raw materials used in this embodiment are: atmospheric air: 45000 Nm³ / h, 98 kPa.

[0041] The products obtained are: liquid air: 13500 Nm³ / h (converted to gaseous state); liquid oxygen: 4000 Nm³ / h; liquid nitrogen: 1200 Nm³ / h; liquid argon: 115 Nm³ / h.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A full-liquid air separation plant independent of air refrigerant liquefaction and air separation rectification, characterized in that: This includes air liquefaction systems, air distillation systems, and liquid air storage tanks, liquid oxygen storage tanks, liquid nitrogen storage tanks, and liquid argon storage tanks; The air liquefaction system includes a liquefied air compressor, a liquefied refrigerated dryer, a liquefied molecular sieve, a circulator, a hot-end expander, a hot-end cooler, a cold-end expander, a cold-end cooler, a hot-end heat exchanger, and a cold-end heat exchanger; the air distillation system includes a distillation air compressor, a distillation nitrogen-water precooling system, a distillation molecular sieve, a main heat exchanger, a distillation column, a distillation subcooler, a crude argon column, and a refined argon column; The liquefied air compressor is provided with a set of inlets and outlets, namely a liquefied air inlet and a liquefied air outlet; the liquefied air dryer is provided with a condensate drain outlet and a set of inlets and outlets, namely a pre-cooled air inlet and a pre-cooled air outlet. The liquefied molecular sieve is provided with two sets of inlets and outlets, namely a liquefied purified air inlet and a liquefied purified air outlet, and a liquefied waste nitrogen inlet and a liquefied waste nitrogen outlet; The circulating machine is equipped with a set of inlets and outlets, namely a circulating air inlet and a circulating air outlet; The cold-end expander is provided with two sets of inlets and outlets, namely, the cold-end pressurization air inlet and the cold-end pressurization air outlet, the cold-end expansion air inlet and the cold-end expansion air outlet; The cold end cooler is provided with a set of inlets and outlets, namely a cold end air inlet and a cold end air outlet; The hot-end expander is provided with two sets of inlets and outlets, namely, hot-end pressurization air inlet and hot-end pressurization air outlet, hot-end expansion air inlet and hot-end expansion air outlet; The hot-end cooler is provided with a set of inlets and outlets, namely a hot-end air inlet and a hot-end air outlet; The hot end heat exchanger is provided with three sets of inlets and outlets, namely the first inlet and the first outlet of the hot end heat exchange, the second inlet and the second outlet of the hot end heat exchange, and the third inlet and the third outlet of the hot end heat exchange. The cold end heat exchanger is provided with two sets of inlets and outlets, namely a first cold end heat exchange inlet and a first cold end heat exchange outlet, a second cold end heat exchange inlet and a second cold end heat exchange outlet. The liquid air storage tank is provided with a liquid air inlet and a liquid air outlet. The distillation air compressor is equipped with a set of inlets and outlets, namely a distillation air inlet and a distillation air outlet; The distillation nitrogen water precooling system is equipped with a condensate discharge port and a set of inlets and outlets, which are respectively a cooling air inlet and a cooling air outlet. The distillation molecular sieve is provided with two sets of inlets and outlets, namely, a distillation purified air inlet and a distillation purified air outlet, a distillation waste nitrogen inlet and a distillation waste nitrogen outlet; The main heat exchanger is provided with four sets of inlets and outlets, namely, heat exchange first inlet, heat exchange first outlet, heat exchange second outlet, heat exchange second inlet, heat exchange third outlet, heat exchange third inlet, heat exchange fourth outlet, and heat exchange fourth inlet; The distillation column is equipped with a compressed air inlet, a lower column liquid air inlet, a lower column medium-pressure nitrogen outlet, a lower column nitrogen outlet, a main column condenser / evaporator nitrogen inlet, a main column condenser / evaporator liquid nitrogen outlet, an upper column liquid nitrogen inlet, an upper column waste nitrogen outlet, an upper column nitrogen outlet, an upper column oxygen outlet, an upper column argon fraction outlet, an upper column crude liquid argon inlet, an upper column liquid air inlet, an upper column liquid air vapor inlet, an upper column liquid air reflux port, an upper column liquid oxygen outlet, and a lower column liquid air outlet. The distillation subcooler is provided with five sets of inlets and outlets, namely the first distillation subcooling inlet, the first distillation subcooling outlet, the second distillation subcooling inlet, the second distillation subcooling outlet, the third distillation subcooling inlet, the third distillation subcooling outlet, the fourth distillation subcooling inlet, the fourth distillation subcooling outlet, the fifth distillation subcooling inlet, and the fifth distillation subcooling outlet. The crude argon column is equipped with an argon fraction inlet, a crude liquid argon outlet, a crude argon gas outlet, an argon gas inlet for the crude argon column condenser-evaporator, a crude liquid argon outlet for the crude argon column condenser-evaporator, a crude liquid argon purification outlet, a crude argon column liquid air inlet, a crude argon column liquid air outlet, and a crude argon column liquid air vapor outlet. The refined argon tower is equipped with a crude liquid argon inlet, a liquid argon outlet, an argon gas outlet, an argon gas inlet for the condenser / evaporator, a liquid argon outlet for the condenser / evaporator, a non-condensable gas outlet, a medium-pressure nitrogen inlet for the condenser / evaporator, a liquid nitrogen outlet for the condenser / evaporator, a liquid nitrogen inlet for the condenser / evaporator, and a nitrogen outlet for the argon tower. The liquefied air inlet is connected to the atmosphere, and the liquefied air outlet, precooled air inlet, precooled air outlet, and liquefied purified air inlet are connected in series in sequence; the cold end pressurized air inlet, cold end pressurized air outlet, cold end air inlet, cold end air outlet, hot end pressurized air inlet, hot end pressurized air outlet, hot end air inlet, hot end air outlet, and hot end heat exchange first inlet are connected in series in sequence. The second outlet of the hot end heat exchange is connected to the air inlet of the cold end expansion end; the air outlet of the cold end expansion end and the second outlet of the cold end heat exchange merge and are then connected to the third inlet of the hot end heat exchange; the third outlet of the hot end heat exchange merges with the liquefied purified air outlet and is then connected to the circulating air inlet. The circulating air outlet is divided into two streams, which are respectively connected to the second inlet of the hot end heat exchange and the air inlet of the cold end pressurization end; the first outlet of the hot end heat exchange is divided into two streams, which are respectively connected to the air inlet of the hot end expansion end and the first inlet of the cold end heat exchange; the air outlet of the hot end expansion end is connected to the second inlet of the cold end heat exchange; the first outlet of the cold end heat exchange is connected to the liquid air inlet of the storage tank; The distillation air inlet is connected to the atmosphere, and the distillation air outlet, cooling air inlet, cooling air outlet, distillation purified air inlet, distillation purified air outlet, first heat exchange inlet, first heat exchange outlet, and compressed air inlet are connected in series in sequence; the storage tank liquid air outlet is connected to the lower tower liquid air inlet; The lower column nitrogen outlet, the main column condenser evaporator nitrogen inlet, the main column condenser evaporator liquid nitrogen outlet, and the first distillation subcooling inlet are connected in series in sequence; the first distillation subcooling outlet is divided into three streams, which are respectively connected to the upper column liquid nitrogen inlet, the argon column liquid nitrogen inlet, and the liquid nitrogen storage tank. The medium-pressure nitrogen outlet of the lower tower, the medium-pressure nitrogen inlet of the argon tower condenser-evaporator, the liquid nitrogen outlet of the argon tower condenser-evaporator, and the liquid nitrogen inlet of the argon tower are connected in series sequentially. The waste nitrogen outlet of the upper column and the nitrogen outlet of the refined argon column are merged and then connected to the third inlet of the distillation subcooler; the third outlet of the distillation subcooler is connected to the fourth inlet of the heat exchanger; the fourth outlet of the heat exchanger is divided into three streams, one stream is directly connected to the atmosphere, and the other two streams are respectively connected to the liquefied waste nitrogen inlet and the distillation waste nitrogen inlet; both the liquefied waste nitrogen outlet and the distillation waste nitrogen outlet are connected to the atmosphere; The upper column nitrogen outlet, the fourth distillation subcooling inlet, the fourth distillation subcooling outlet, and the third heat exchange inlet are connected in series in sequence, and the third heat exchange outlet is connected to the user's nitrogen pipeline network. The upper column oxygen outlet and the fifth distillation subcooling inlet are connected in series; the fifth distillation subcooling outlet and the second heat exchange inlet are connected in series; the second heat exchange outlet is connected to the user's oxygen pipeline network. The argon fraction outlet of the upper column is connected to the argon fraction inlet; The crude liquid argon outlet is connected to the crude liquid argon inlet of the upper tower; The crude argon tower liquid air vapor outlet is connected to the upper tower liquid air vapor inlet; The liquid air outlet of the crude argon tower is connected to the liquid air reflux port of the upper tower. The liquid oxygen outlet of the upper tower is connected to the liquid oxygen storage tank; The lower column liquid air outlet is connected to the second subcooling inlet of the distillation column; the second subcooling outlet of the distillation column is divided into two streams, which are respectively connected to the upper column liquid air inlet and the crude argon column liquid air inlet. The crude argon outlet is connected to the argon inlet of the crude argon tower condenser-evaporator, and the crude liquid argon purification outlet is connected to the crude liquid argon inlet of the refined argon tower; the crude liquid argon outlet of the crude argon tower condenser-evaporator is refluxed into the crude argon tower. The argon outlet of the argon tower is connected to the argon inlet of the argon tower condenser / evaporator; the liquid argon outlet of the argon tower condenser / evaporator is refluxed into the argon tower; and the non-condensable gas outlet is connected to the atmosphere. The liquid argon outlet of the argon refiner is connected to the liquid argon storage tank.

2. The all-liquid air separation unit with independent air-cooled liquefaction and air-separation distillation phases as described in claim 1, characterized in that, The air liquefaction system also includes a subcooled expander; a subcooled end cooler; and a liquefaction subcooler. The liquid air storage tank is provided with a liquid air storage tank compressed air inlet; the subcooled expander is provided with two sets of inlets and outlets, namely a subcooled booster end air inlet, a subcooled booster end air outlet, a subcooled expansion end air inlet, and a subcooled expansion end air outlet; The subcooled end cooler is provided with a set of inlets and outlets, namely a subcooled end air inlet and a subcooled end air outlet; the liquefied subcooler is provided with two sets of inlets and outlets, namely a first liquefied subcooling inlet, a first liquefied subcooling outlet, a second liquefied subcooling inlet, and a second liquefied subcooling outlet. The hot-end heat exchanger is also provided with two sets of inlets and outlets, namely the fourth inlet of hot-end heat exchange, the fourth outlet of hot-end heat exchange, the fifth inlet of hot-end heat exchange, and the fifth outlet of hot-end heat exchange; the cold-end heat exchanger is also provided with two sets of inlets and outlets, namely the third inlet of cold-end heat exchange, the third outlet of cold-end heat exchange, the fourth inlet of cold-end heat exchange, and the fourth outlet of cold-end heat exchange. The third outlet of the hot end heat exchange is divided into two streams. One stream is connected to the circulating air inlet, and the other stream is connected to the subcooled pressurized end air inlet. The subcooled pressurized end air outlet, the subcooled end air inlet, the subcooled end air outlet, the third inlet of the cold end heat exchange, the third outlet of the cold end heat exchange, the fourth inlet of the hot end heat exchange, the fourth outlet of the hot end heat exchange, the third inlet of the cold end heat exchange, the third outlet of the cold end heat exchange, the subcooled expansion end air inlet, the subcooled expansion end air outlet, the second inlet of the liquefied subcooling, the second outlet of the liquefied subcooling, the fourth inlet of the cold end heat exchange, the fourth outlet of the cold end heat exchange, the fifth inlet of the hot end heat exchange, and the liquefied waste nitrogen inlet are connected in series. The cold end heat exchange first outlet, the liquefaction subcooling first inlet, the liquefaction subcooling first outlet, and the storage tank liquid air inlet are connected in series in sequence. The first heat exchange outlet is divided into two streams: one stream is connected to the compressed air inlet of the distillation column, and the other stream is connected to the compressed air inlet of the liquid air storage tank.

3. The all-liquid air separation unit with independent air refrigeration liquefaction and air separation distillation phases as described in claim 1, characterized in that, The first outlet of the distillation subcooler is connected to the liquid nitrogen inlet of the upper column after passing through a throttle valve and a U-tube in sequence, and a branch is split at the U-tube to connect to the liquid nitrogen storage tank.

4. The all-liquid air separation unit with independent air refrigeration liquefaction and air separation distillation phases as described in claim 1, characterized in that, The liquefied air compressor, distillation air compressor, and circulating compressor are all centrifugal air compressors and are equipped with a frequency converter starter.

5. The all-liquid air separation unit with independent air refrigeration liquefaction and air separation distillation phases as described in claim 2, characterized in that, The liquid air storage tank is a non-self-pressurizing tank.

6. The all-liquid air separation unit with independent air-cooled liquefaction and air-separation distillation phases according to claim 1, characterized in that, The liquid air storage tank is a pressure storage tank.

7. The all-liquid air separation unit with independent air refrigeration liquefaction and air separation distillation phases according to claim 1, characterized in that, The liquid air storage tank is also equipped with an external liquid air inlet for inputting low-cost external liquid air.

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