Air separation system

Abstract

To provide an air separation system comprising a plurality of air separation devices, in which a device that is relatively smaller than other rectification columns such as a low pressure column is configured as a common module.SOLUTION: An air separation system B1 comprises a plurality of air separation devices 1, 2, and a pure argon production unit C1 that produces product argon using an argon-enriched product derived from the plurality of air separation devices. The air separation system B1 further comprises a product oxygen gas production unit C2 that produces product oxygen gas using liquefied oxygen derived from the plurality of air separation devices.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present disclosure relates to an air separation system including a plurality of air separation devices.

Background Art

[0002] There is an industrial demand for obtaining air separation gases (oxygen, nitrogen, argon, etc.) by cryogenic separation of air. When the demand becomes large-scale, it may be possible to install an air separation device near the customer and supply it through a pipeline. According to Patent Document 1, it is desirable to construct an air separation device in a modular manner. The module may be transported over a long distance from the construction site to the destination. Therefore, the module must be of a transportable size. According to Patent Document 2, an air separation device may be composed of a module in which a plurality of air separation devices are arranged with respect to the production of argon, and a common module shared by these plurality of modules. According to Patent Document 3, in order to obtain oxygen gas in an air separation device, an oxygen-enriched liquid may be rectified to obtain an oxygen liquid, which is evaporated and heated by heat exchange with high-pressure air or nitrogen in a heat exchanger and supplied as oxygen gas. This oxygen gas supply method can be arranged and operated (in a plug-in manner) by connecting with piping without being incorporated into the main heat exchanger of the air separation device as a module for oxygen supply.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Due to the increasing demand for air separation gases (nitrogen, oxygen, argon, etc.), air separation equipment is also becoming larger. For large consumers, air separation gases are supplied by on-site air separation equipment, which requires transporting the equipment to the consumer's factory. This necessitates constructing air separation module units to a transportable size. As a result, multiple air separation units are installed to meet demand, but this faces challenges such as cost reduction requirements and limited installation space (constraints).

[0005] This disclosure provides an air separation system comprising multiple air separation devices, in which equipment relatively smaller than other rectification columns, such as low-pressure columns (e.g., pure argon rectification columns or high-pressure oxygen production modules), is configured as a common module. Furthermore, this disclosure provides an air separation system equipped with the above-mentioned common module that can improve thermal efficiency. [Means for solving the problem]

[0006] The air separation system of this disclosure comprises a plurality of air separation devices and a pure argon production unit that produces product argon using argon enriched materials derived from the plurality of air separation devices. The air separation system may further include a product oxygen gas production unit that produces product oxygen gas using liquefied oxygen discharged from the plurality of air separation devices. Product argon may be in liquid, gaseous, or gas-liquid mixture form (the same definition applies hereafter unless otherwise specified).

[0007] The first air separation system (A1) is, A plurality of air separation devices (1, 2, ..., n) comprising: a main heat exchanger (11, 21) into which raw material air is introduced; a first rectification column (12, 22) into which raw material air that has passed through the main heat exchanger (11, 21) is introduced; a first condenser (13, 23) for condensing nitrogen gas; a second rectification column (14, 24) into which nitrogen-containing liquid discharged from the first rectification column (12, 22) is introduced; a third rectification column (15, 25) into which argon-containing oxygen-enriched material discharged from the second rectification column (14, 24) is introduced; and a second condensation section (16, 26) for condensing the gas discharged from the third rectification column (15, 25), The system includes a pure argon production unit (C1) that produces product argon using argon-enriched material (which may be in gaseous, liquid, or gas-liquid mixed form) discharged from the third rectification columns (15, 25) of each of the aforementioned plurality of air separation devices (1, 2, ..., n). The value of n is 3 or greater, and can be set to a large number corresponding to the design of the common module. The upper limit of the value of n may be, for example, 10 or less, 30 or less, or 50 or less, but is not particularly limited. The aforementioned pure argon production unit (C1) is: The argon-enriched material that has passed through the main heat exchangers (11, 21) is introduced into the first heat exchanger (E1), The system may also include a pure argon rectification column (C11) into which the argon-enriched material that has passed through the first heat exchanger (E1) is introduced.

[0008] The second air separation system (B1, B2, B3, B4) is, Multiple air separation devices (1, 2, ..., n) comprising: a main heat exchanger (11, 21) into which raw material air is introduced; a first rectification column (12, 22) into which raw material air that has passed through the main heat exchanger (11, 21) is introduced; a first condenser (13, 23) for condensing nitrogen gas; a second rectification column (14, 24) into which nitrogen-containing liquid discharged from the first rectification column (12, 22) is introduced; a third rectification column (15, 25) into which argon-containing oxygen-enriched material discharged from the second rectification column (14, 24) is introduced; and a second condensation section (16, 26) for condensing the gas discharged from the third rectification column (15, 25), A pure argon production unit (C1) that produces product argon using argon-enriched material (which may be in gaseous, liquid, or gas-liquid mixed form) discharged from the third rectification columns (15, 25) of each of the aforementioned multiple air separation units (1, 2, ..., n), The system includes a product oxygen gas production unit (C2) that produces product oxygen gas (GOX) using liquefied oxygen (LOX, which may be in a gas-liquid mixed state) discharged from the second rectification columns (14, 24) of each of the plurality of air separation devices (1, 2, ..., n). The pure argon production unit (C1) may include a first heat exchanger (E1) into which the argon-enriched material that has passed through the main heat exchangers (11, 21) is introduced, and a pure argon rectification column (C11) into which the argon-enriched material that has passed through the first heat exchanger (E1) is introduced. The product oxygen gas production section (C2) may include a second heat exchanger (E2) into which gas (nitrogen-containing gas) discharged from the top of the pure argon rectification column (C11) is introduced, and into which liquefied oxygen (LOX, which may be in a gas-liquid mixed state) discharged from the first condenser (13, 23) or the second rectification column (14, 24) is introduced. The product oxygen gas production section (C2) may consist of a single heat exchanger for both the first heat exchanger (E1) and the second heat exchanger (E2). The first heat exchanger may also perform the function of the second heat exchanger. The product oxygen gas production unit (C2) may include a compressor (C22) for compressing high-purity nitrogen gas (GAN) discharged from the plurality of air separation units (1, 2), an expansion turbine (C23) to which the compressed high-purity nitrogen gas (GAN) is introduced into the heat exchangers (E2, E11) and a portion of it is branched off and introduced, and a gas-liquid separation unit (C24) to which the high-purity nitrogen gas (GAN) is introduced after being cooled in the second heat exchanger (E2).

[0009] The first rectification column (12, 22) of the first and second air separation systems (A1, B1, B2, B3, B4) is a high-pressure rectification column that performs rectification under higher pressure than the second rectification column (14, 24), and the second rectification column (14, 24) may be a low-pressure rectification column. The second rectification column may be separated into two or more columns, or it may consist of a single column. The third rectification columns (15, 25) of the first and second air separation systems (A1, B1, B2, B3, B4) may be crude argon rectification columns. The third rectification column may be separated into two or more columns, or it may consist of a single column. The pure argon production section (C1) of the first and second air separation systems (A1, B1, B2, B3, B4) produces product argon. Product argon is argon gas and / or liquid argon. The functional elements that constitute the multiple air separation devices (1, 2, ..., n) of the first and second air separation systems (A1, B1, B2, B3, B4), such as rectification columns, heat exchangers (including subcoolers), condensers, reboilers, compressors, expansion turbines, air purification sections, piping, various valves, various sensors, control units, and equipment layouts, may be the same or different, and there are no particular restrictions on the selection and combination of each element, which can be freely set.

[0010] (effect) (1) By making the pure argon production unit, or the pure argon production unit and the product oxygen gas production unit, a common module, it becomes possible to miniaturize the air separation unit, enabling flexibility in manufacturing costs, transportation (i.e., portability), and installation. (2) By using the same heat exchanger for both the pure argon production section and the product oxygen gas production section, the heat exchange efficiency can be increased. (3) By using the same heat exchanger for both the pure argon production section and the product oxygen gas production section, power consumption can be reduced. [Brief explanation of the drawing]

[0011] [Figure 1A] Figure 1A shows the air separation system of Embodiment 1. [Figure 1B]FIG. 1B shows the air separation system of Embodiment 2. [Figure 1C] FIG. 1C shows the air separation system of Embodiment 3. [Figure 1D] FIG. 1D shows the air separation system of Embodiment 4. [Figure 2] FIG. 2 shows the air separation system of Embodiment 5. **Embodiments for Carrying Out the Invention**

[0012] Some embodiments of the present invention will be described below. The embodiments described below illustrate an example of the present invention. The present invention is not limited to the following embodiments, and various modified forms implemented within the scope of not changing the gist of the present invention are also included. Note that not all of the configurations described below are essential configurations of the present invention.

[0013] (Embodiment 1) The air separation system B1 of Embodiment 1 will be described with reference to FIG. 1A. The air separation system B1 includes first and second air separation devices 1 and 2, a pure argon production section C1 of a common module, and a product oxygen gas production section C2. The air separation system B1 supplies the crude argon-rich material (Crude Argon) and high-purity nitrogen gas (GAN) derived from the respective air separation devices 1 and 2 to the pure argon production section C1 and the product oxygen gas production section C2 of the common module to produce product argon (LAr) and product oxygen gas (GOX).

[0014] In the present embodiment, the first and second air separation devices 1 and 2 have the same components. The first air separation device 1 includes a main heat exchanger 11, a first rectification column (high-pressure rectification column) 12, a second rectification column (low-pressure rectification column) 14, a third rectification column (crude argon rectification column) 15, a first condensation section 13, a second condensation section 16, a subcooler 17, and an expansion turbine 18. The second air separation unit 2 comprises a main heat exchanger 21, a first rectification column (high-pressure rectification column) 22, a second rectification column (low-pressure rectification column) 24, a third rectification column (crude argon rectification column) 25, a first condenser 23, a second condenser 26, a subcooler 27, and an expansion turbine 28. The following description will focus on the first air separation unit 1, but the second air separation unit 2 has the same function and will therefore not be described.

[0015] (High-pressure rectification column) The raw air passes through the main heat exchanger 11 and is introduced via piping L1 to the bottom 121 of the first rectification column 12 or to the lower section of the rectification unit 123. In the first rectification column 12, the raw air is separated into an oxygen-enriched liquid and a nitrogen-containing liquid (LIN, liquefied nitrogen). The first condenser (nitrogen condenser) 13 condenses (liquefies) the nitrogen gas discharged from the top 125 of the first rectification column 12 via piping L25c and returns it to the first rectification column 12. Some of the oxygen gas discharged from the top of the first condenser (nitrogen condenser) 13 is sent to the bottom 141 of the second rectification column 14 or the lower rectification section 142. Another portion discharged from the top of the first condenser 13 is introduced to the main heat exchanger 11 via piping L32, where it undergoes heat exchange and is then used in the expansion turbine 18. It then passes through the main heat exchanger 11 again and is discharged as waste gas (WG). The liquefied oxygen (LOX) discharged from the bottom or lower part of the first condenser 13 is transported via piping L31 to piping L91 of the product oxygen gas production unit C2 by pump P1. The liquefied oxygen (LOX) discharged from the first condenser 23 of the second air separator 2 is also transported to piping L91 of the product oxygen gas production unit C2.

[0016] The oxygen-enriched liquid is discharged from the bottom 121 of the first rectification column 12 via piping L21, and after heat exchange in the subcooler 17, a portion of it is introduced to the middle rectification section 143 of the second rectification column 14 via branch piping L21a, and the remaining portion is introduced to the second condenser 16 via branch piping L21b. Valves may be provided in piping L21, branch piping L21a, and L21b, and may function as flow control valves or on / off gate valves. The raw air may be treated in an air purification unit to remove impurities before being introduced into the main heat exchanger 11.

[0017] (Low-pressure rectification column) The nitrogen-containing liquid (LIN) introduced into the upper rectification section 144 of the second rectification column 14 is rectified in the second rectification column 14. The nitrogen-containing liquid (LIN) is delivered via branch pipe L93b, which is branched from piping L93 of the product oxygen gas production section C2. The high-purity oxygen solution discharged from the bottom 141 of the second rectification column 14 is sent to the first condensation section 13. The argon-containing oxygen-enriched material (which may be gaseous, liquid, or a gas-liquid mixture) is discharged from the lower rectification section 142 or intermediate rectification section 143 of the second rectification column 14 via piping L42 and introduced into the bottom section 151 or lower rectification section 153 of the third rectification column 15 (crude argon rectification column).

[0018] High-purity nitrogen gas (GAN) is discharged from the top 145 of the second rectification column 14 via piping L45, undergoes heat exchange in the subcooler 17, then undergoes heat exchange in the main heat exchanger 11, and is then sent to piping L82 of the pure argon production section C1 and piping L92 of the product oxygen gas production section C2. High-purity nitrogen gas (GAN) discharged from the second rectification column 24 of the second air separation unit 2 is also sent to piping L82 of the pure argon production section C1 and piping L92 of the product oxygen gas production section C2.

[0019] The gas discharged from the upper rectification section 144 or the intermediate rectification section 143 of the second rectification column 14 via piping L43 merges with piping L32, passes through the main heat exchanger E1, is sent to the expansion turbine 18 for use in turbine driving, and is then returned to the main heat exchanger 11 and discharged as waste gas (WG).

[0020] (Crude argon rectification column) The third rectification column 15 rectifies the argon-containing oxygen-enriched material to obtain argon-enriched material (crude argon). The rectification gas (argon-enriched gas) of the argon-containing oxygen-enriched material is discharged from the top of the third rectification column 155 via piping L52, sent to the second condensation section 16, condensed (liquefied), and then returned to the top of the column 155. The gas from the oxygen-enriched liquid discharged from the top of the second condensation section 16 is introduced into the intermediate rectification section 143 of the second rectification column 14 via piping L62. The argon-enriched material (which may be gaseous, liquid, or a gas-liquid mixture) is discharged from the upper section or top section 155 of the rectification section 153 of the third rectification column 15 via piping L55, passes through the main heat exchanger 11, and is then sent to piping L81 of the pure argon production section C1. The argon-enriched material discharged from the third rectification column 15 of the second air separation unit 2 is also sent to piping L81 of the pure argon production section C1. The rectified liquid of the argon-containing oxygen-enriched material is discharged from the bottom 151 of the third rectification column 15 via piping L51 and returned to the lower rectification section 142 or the intermediate rectification section 143 of the second rectification column 14.

[0021] (Pure Argon Production Department) The pure argon production section C1 comprises a first heat exchanger E1, a pure argon rectification column C11, a third condenser C12, and a third heat exchanger C13 (or reboiler). The pure argon rectification column C11 rectifies the argon-enriched material discharged from the first and second air separation units 1 and 2. The argon-enriched material discharged from the first and second air separation units 1 and 2 is compressed to a predetermined pressure by compressors 61 located in piping L81. The compressed argon-enriched material (gas) is sent via piping L81 to the first heat exchanger E1 for cooling, then liquefied in the third heat exchanger C13, and introduced into the intermediate stage of the rectification section C112 of the pure argon rectification column C11. The liquid argon discharged from the bottom C111 of the pure argon rectification column C11 is sent to the third heat exchanger C13 for cooling, and then returned to the bottom C111. The liquid argon (LAr) discharged from the bottom C111 is taken out as the product via piping L83. Low-boiling-point gas components G, such as nitrogen, are extracted from the top of the tower C113 via piping L84.

[0022] In the third condensation section C12, argon gas is introduced from the top section C113 of the pure argon rectification column C11, and the argon liquid condensed in the third condensation section C12 is returned to the pure argon rectification column C11. The high-purity nitrogen gas (GAN) discharged from the first and second air separation units 1 and 2 is routed through piping. L82 The gas is compressed to a predetermined pressure by compressors 62 located in each section. The compressed high-purity nitrogen gas (GAN) is sent to the first heat exchanger E1 via piping L82 for cooling, then liquefied in the third heat exchanger C13, and introduced as cold to the third condensation section C12. In addition, nitrogen-containing liquid (LIN) discharged from the product oxygen gas production section C2 is introduced as cold to the third condensation section C12 via piping L93a. A portion of the gas (nitrogen-containing gas) discharged from the top of the third condensation section C12 is sent to the first heat exchanger E1 via piping L85 and branch piping L85a, where it is used as cooling energy and then discharged as nitrogen gas GAN1. The remaining gas (nitrogen-containing gas) is sent to the second heat exchanger E2 of the product oxygen gas production section C2 via branch piping L85b, where it is used as cooling energy and then discharged as nitrogen gas GAN1. This nitrogen gas GAN1 may be supplied as a product or recovered as gas to be introduced into another system.

[0023] (Product Oxygen Gas Manufacturing Department) The product oxygen gas production section C2 includes a second heat exchanger E2, a compressor C22, an expansion turbine C23, and a gas-liquid separation section C24. High-purity nitrogen gas (GAN) discharged from the first and second air separation units 1 and 2 is compressed by compressor C22 via piping L92 and then sent to the second heat exchanger E2 for cooling. A portion of the high-purity nitrogen gas (GAN) introduced into the second heat exchanger E2 is discharged via branch piping L92b and sent to expansion turbine C23 for use, before returning to the second heat exchanger E2 and merging with piping L94. The high-purity nitrogen gas (GAN) cooled in the second heat exchanger E2 becomes a gas-liquid state and is sent to the gas-liquid separation unit C24. The nitrogen-containing liquid (LIN) separated in the gas-liquid separation unit C24 is taken out via piping L93 and introduced via branch piping L93b to the upper rectification section 144 of the second rectification column 14 of the first air separation unit 1, and also introduced via branch piping L93c to the upper rectification section of the second rectification column 24 of the second air separation unit 2. Furthermore, a portion of the nitrogen-containing liquid (LIN) is transferred to pipe L85 via branch pipe L93a and sent to the third condensation section C12. The high-purity nitrogen gas (GAN) separated in the gas-liquid separation section C24 is sent back to the second heat exchanger E2 via piping L94 for cooling, and then joins piping L92 upstream of the compressor C22. The liquefied oxygen (LOX) discharged from the first and second air separation units 1 and 2 merges into piping L91 and is introduced into the second heat exchanger E2, where it releases its cold energy and is extracted as product oxygen gas (GOX). Furthermore, depending on the operating conditions, the compressor C22 and expansion turbine C23 may be shut off. A bypass piping that does not go through the compressor C22 may also be provided. In this embodiment, the first and second air separation devices 1 and 2 have been described as having the same components, but the components may be different as long as they function as air separation devices.

[0024] (Embodiment 2) The air separation system B2 of Embodiment 2 will be described with reference to Figure 1B. The air separation system B2 comprises first and second air separation devices 1 and 2, and a common module for producing pure argon and oxygen gas C3. The air separation system B2 supplies crude argon enriched material (Crude Argon) and high-purity nitrogen gas (GAN) derived from the respective air separation devices 1 and 2 to the common module's pure argon and oxygen gas production unit C3 to produce liquid argon (LAr) and product oxygen gas (GOX). The same reference numerals as in Embodiment 1 have the same function, so their explanation is omitted. The pure argon and oxygen gas production section C3 includes a fourth heat exchange section E11 that combines the functions of the first and second heat exchange sections E1 and E2 of Embodiment 1. In the fourth heat exchange section E11, pipes L81, L82, L92, L94, and L92b pass through, similar to Embodiment 1. The gas (nitrogen-containing gas) discharged from the top of the third condenser C12 is sent to the fourth heat exchanger E11 via piping L86 and used as cooling energy, before joining piping L92 upstream of the compressor C22.

[0025] (Embodiment 3) The air separation system B3 of Embodiment 3 will be described using Figure 1C. Compared with Embodiment 2 (Figure 1B), Embodiment 3 has a configuration in which the piping L82 branches off from the piping between the compressor C22 and the fourth heat exchanger E11, and the compressor 62 is omitted.

[0026] (Embodiment 4) The air separation system B4 of Embodiment 4 will be described with reference to Figure 1D. Compared to Embodiment 1 (Figure 1A), Embodiment 4 is configured such that the argon-enriched material discharged from the upper stage of the rectification section 153 or the top of the column 155 of the third rectification column 15 via piping L55 is introduced into the intermediate stage of the rectification section C112 of the pure argon rectification column C11 without passing through the main heat exchanger 11, compressor 61, first heat exchanger E1, and third heat exchanger C13. Similarly, the argon-enriched material sent from the second air separation device 2 is introduced into the intermediate stage of the rectification section C112 of the pure argon rectification column C11 without passing through the main heat exchanger 11, compressor 61, first heat exchanger E1, and third heat exchanger C13.

[0027] (Embodiment 5) The air separation system A1 of Embodiment 5 will be described with reference to Figure 2. The air separation system A1 comprises first and second air separation devices 1 and 2, and a common module pure argon production unit C1. The air separation system A1 supplies crude argon enriched material (Crude Argon) and high-purity nitrogen gas (GAN) derived from the respective air separation devices 1 and 2 to the common module pure argon production unit C1 to produce liquid argon product. The same reference numerals as in Embodiment 1 have the same function, so their explanation is omitted.

[0028] In this embodiment, the oxygen can be extracted in the form of liquefied oxygen (LOX), and additional components (such as a heat exchange means and an expansion valve) may be added to allow extraction as product oxygen gas. The nitrogen-containing liquid (LIN) is introduced as a cold coolant to the third condensation section C12 via piping L101. The nitrogen-containing liquid (LIN) is also introduced to the upper rectification section 144 of the second rectification column 14 of the first air separation unit 1 via piping L100a and branch piping L100b, and to the upper rectification section of the second rectification column 24 of the second air separation unit 2 via branch piping L100c.

[0029] A portion of the gas (nitrogen-containing gas) discharged from the top of the third condenser C12 is sent to the first heat exchanger E1 via piping L85 and branch piping L85a, where it is used as cooling energy and then discharged as nitrogen gas GAN1. This nitrogen gas GAN1 may be supplied as a product or recovered as gas for introduction into another system. The remaining gas (nitrogen-containing gas) is joined with the high-purity nitrogen gas (GAN) in piping L45 of the first and second air separation units 1 and 2 via branch piping L85c.

[0030] (Another embodiment) (1) The liquefied oxygen (LOX) supplied from the first and second air separation units 1 and 2 may not be merged in piping L91, but may be introduced to the second heat exchanger E2 or the fourth heat exchanger E11 via their respective piping. (2) A purification device for purifying the raw material air may be provided upstream of the main heat exchanger E1. (4) Each rectification column may be equipped with a thermometer, pressure gauge, liquid level gauge, etc. (5) Each pipe may be equipped with a thermometer, pressure gauge, flow meter, various valves (for example, a pressure regulating valve, a flow regulating valve, a gate valve), etc. (6) The expansion turbine 18, compressor C22, and expansion turbine C23 may not be provided. (7) In embodiments 1 to 5, the first and second air separators 1 and 2 were described as having the same components, but the components may be different as long as they function as air separators.

[0031] (Examples) In the configuration shown in Figure 1A, the return piping L82 Without performing recirculation by piping L82 Compared to the comparative example where exhaust gas was discharged from the return piping, L82 In an embodiment where reflux was implemented, simulations confirmed that the amount of liquid nitrogen produced in the product oxygen gas production section C2 (or piping L93) increased by approximately 5.7 mol%. This simulation revealed that the thermal efficiency of the apparatus according to the present invention was improved. [Explanation of Symbols]

[0032] A1, B1, B2, B3, B4 Air Separation System C1 Pure Argon Production Department C2 Product Oxygen Gas Manufacturing Department C3 Argon and Oxygen Gas Production Unit C11 Pure Argon Distillation Column C12 Third Condensate C22 Compressor C23 Expansion Turbine C24 Gas-Liquid Separation Unit E1 First heat exchange section E2 Second heat exchange section E11 Fourth heat exchange section 1. First air separation device 2. Second air separation device 11 Main heat exchanger 12. First rectification column (high-pressure rectification column) 13. First condensation stage 14. Second rectification column (low-pressure rectification column) 15. Third rectification column (crude argon rectification column) 16 Second condensation section 17 Subcooler 18 Expansion Turbine

Claims

1. Multiple air separation devices, A pure argon production unit that produces product argon using argon-enriched materials derived from the aforementioned multiple air separation devices, The system includes a product oxygen gas production unit that produces product oxygen gas using liquefied oxygen supplied from the plurality of air separation devices, The aforementioned pure argon production unit is The first heat exchanger into which the argon-enriched material is introduced, A pure argon rectification column into which the argon-enriched material that has passed through the first heat exchanger is introduced, The system includes a third condensation section into which high-purity nitrogen gas discharged from the aforementioned multiple air separation devices is introduced as a cold coolant, and which condenses the argon gas from the pure argon rectification column. The product oxygen gas production unit comprises a second heat exchanger into which the liquid oxygen is introduced, The high-purity nitrogen gas discharged from the third condensation section is sent to the first heat exchanger and the second heat exchanger. Air separation system.

2. The first heat exchanger and the second heat exchanger are composed of a single heat exchanger, The air separation system according to claim 1.

3. The aforementioned product oxygen gas manufacturing unit is: A compressor for compressing high-purity nitrogen gas discharged from the aforementioned multiple air separation devices, The high-purity nitrogen gas compressed by the compressor is introduced into the second heat exchanger, and a portion of it is branched off and introduced into an expansion turbine, The system includes a gas-liquid separation section into which the high-purity nitrogen gas cooled by the second heat exchanger is introduced, The air separation system according to claim 1 or 2.

Images