JP4206083B2 - Argon production method using cryogenic air separator - Google Patents

Description

  The present invention relates to an argon production method using a cryogenic air separation device that separates air into nitrogen and oxygen, and more particularly, a cryogenic air separation that makes it possible to produce product liquid argon efficiently at a lower cost. The present invention relates to an argon production method using an apparatus.

  First, a general cryogenic air separation apparatus according to a conventional example for carrying out an argon production method will be described with reference to FIG. 8 of a schematic system explanatory view thereof. That is, the general cryogenic air separation apparatus according to this conventional example includes a raw material air compressor 51 that compresses raw material air, and a precooling that cools the air compressed by the raw material air compressor 51 to about 10 to 40 ° C. A unit 52, an adsorption tower unit 53 for removing carbon dioxide and moisture in the raw air cooled by the precooling unit 52, and main heat exchange for cooling the air pretreated by the adsorption tower unit 53 to near the liquefaction temperature. Instrument 54.

  Furthermore, a double rectification column 55 comprising an upper column 55a and a lower column 55b each having a main condenser 55c at the bottom for rectifying and separating nitrogen, oxygen and the like in the low-temperature air sent from the main heat exchanger 54; The crude argon tower 56 for concentrating the argon in the vapor containing argon introduced from the upper tower 55a, and the crude argon taken out from the crude argon tower 56 and passing through the main heat exchanger 54 are 0.2-0. A crude argon compressor 57 that compresses to a pressure of about 4 MPaG is provided. Furthermore, an argon purification device 58 that removes oxygen in the crude argon compressed by the crude argon compressor 57 to convert it into modified argon, a purified argon column 59 that purifies the modified argon purified by the argon purification device 58, An expansion turbine 60 that generates cold for maintaining the entire apparatus at a low temperature, and various facilities attached thereto are provided.

  According to the cryogenic air separation apparatus according to the conventional example, argon is usually produced as follows. That is, the argon contained in the air in an amount of about 0.93% is concentrated in oxygen in the middle to the lower part of the upper column 55a of the double rectification column 55. A gas containing about 8 to 12% argon is extracted from this position and supplied to the bottom of the crude argon column 56. The gas supplied to the crude argon column 56 comes into contact with the liquid flowing down while rising in the column, and the argon is gradually concentrated. At the top of the crude argon column 56, a gas containing 95% or more of argon (the remainder) Is a small amount of oxygen and nitrogen.) Most of this gas is supplied to the crude argon condenser 56 a, condensed and refluxed to the lower part of the crude argon column 56. The remainder is withdrawn in the form of gas, heated to room temperature in the main heat exchanger 54, compressed by the crude argon compressor 57, and supplied to the argon purifier 58. Then, oxygen contained in the crude argon is removed in the argon purifier 58.

  Oxygen contained in the crude argon is heated by mixing hydrogen in the crude argon, for example, and oxygen and hydrogen are chemically oxidized by the catalyst, and the generated moisture is adsorbed by the adsorbent and removed. It depends on the removal method such as. The modified argon from which oxygen has been removed flows through the modified argon supply line 63, is cooled again through the main heat exchanger 54, and is introduced into the middle of the purified argon column 59. Residual hydrogen, nitrogen, and the like are removed by rectification in the purified argon column 59 and extracted from the bottom of the purified argon column 59 as high-purity product liquid argon. The line passing through the supercooler 64 and the main heat exchanger 54 from the top of the upper tower 55a is a GN discharge line 65 for extracting nitrogen products, and passes through the main heat exchanger 54 from the lower part of the upper tower 55a. The line is a GO discharge line 66 for extracting oxygen products.

Incidentally, the oxygen concentration in the crude argon depends on the number of rectification stages installed in the crude argon column. That is, as the number of equipped rectification stages increases, the oxygen concentration in the crude argon decreases.
As a result, the amount of hydrogen supplied to the argon purifier for removing oxygen is reduced, which is economical. However, since the pressure of the crude argon at the crude argon outlet of the crude argon column decreases as the number of rectification stages equipped in the crude argon column increases, it is finally impossible to obtain a pressure sufficient to send the crude argon. .

By the way, the oxygen concentration in the crude argon obtained by the crude argon tower using a normal rectifying dish is 2 to 5%. Therefore, instead of a normal rectifying dish, using a regular packing with a lower pressure loss per stage, and equipped with a larger number of rectifying stages in the crude argon column, crude argon with a lower oxygen concentration can be obtained. There is what was obtained (for example, refer to Patent Document 1).
Japanese Patent No. 2516680

  An energy cost related to the driving force of the raw material air compressor 51 occupies most of the operating cost in the cryogenic air separation device, and the driving force of the raw material air compressor is generally determined as follows. That is, in the cryogenic air separation apparatus, a waste nitrogen extraction line 61 is provided in the upper part of the upper column 55a of the double rectification column 55, and the waste nitrogen extracted in the waste nitrogen extraction line 61 is subjected to main heat exchange. It is heated through the vessel 54. A part of the heated waste nitrogen is utilized for adsorbent regeneration of the adsorption tower unit 53, and the rest is released into the atmosphere. Therefore, when the pressure at the waste nitrogen extraction position of the upper tower 55a is set to a pressure obtained by adding atmospheric pressure to the sum of the pressure losses of the adsorption tower unit 53, the main heat exchanger 54, and the waste nitrogen extraction line 61, the raw material The required power of the air compressor 51 is minimized. On the other hand, the pressure of the crude argon outlet 56b of the crude argon column 56 is equal to the pressure of the waste nitrogen outlet, and the rectification provided between the waste nitrogen outlet of the upper tower 55a and the gas outlet to the bottom of the crude argon tower. The pressure loss of the dish is added, and the pressure is obtained by subtracting the pressure loss of the rectifying dish provided in the crude argon column.

  In the crude argon column 56, rectification is mainly performed for separation of argon and oxygen. However, since the pressure difference between the vapor pressures of argon and oxygen is small, a large number of rectification stages are required for the separation. . On the other hand, for the reasons described above, the pressure at the crude argon outlet 56b drops in proportion to the increase in the number of rectifying stages, and at the crude argon outlet 56b, it drops to a pressure slightly higher than atmospheric pressure. The crude argon extracted through the crude argon extraction line 62 connected to the crude argon extraction port 56b needs to be heated to room temperature and then pressurized to the pressure required by the argon purifier 58. It is generally performed by a crude argon compressor 57.

  In order to extract crude argon from the crude argon outlet 56b in order to produce high purity product liquid argon by the cryogenic air separator according to the conventional example, the pressure of the crude argon at the crude argon outlet 56b is as described above. Therefore, the number of rectification stages in the crude argon column is limited. Moreover, the rough | crude argon compressor 57 for pressurizing the rough | crude argon is required.

  Accordingly, an object of the present invention is to produce argon by a cryogenic air separation device that makes it possible to supply high-pressure crude argon to an argon purification device and a purified argon column without providing auxiliary equipment such as a crude argon compressor. Is to provide a method.

  The inventors of the present invention can reliably extract the crude argon from the crude argon extraction port of the crude argon column in a liquid state, that is, as liquid crude argon, even if the pressure of the crude argon is low. Further, it was considered that the liquid crude argon extracted from the crude argon outlet can be pressurized with the liquid crude argon head caused by the difference in height between the crude argon outlet and the main heat exchanger. Then, whether or not the liquid crude argon can be evaporated by the main heat exchanger, and knowing that the liquid crude argon can be evaporated by the main heat exchanger, the present invention has been realized. It is.

In order to achieve the above object, the means adopted by the argon production method using the cryogenic air separator according to claim 1 of the present invention is a raw material air compressor for compressing raw material air and the raw material air compressor. A pre-cooling unit that cools the compressed air to a temperature of about 10 to 40 ° C., an adsorption tower unit that removes carbon dioxide and moisture in the compressed air cooled by the pre-cooling unit, and a raw material air purified by the adsorption tower unit A main heat exchanger that cools the liquid to a temperature near its liquefaction, a double rectification column that rectifies and separates nitrogen and oxygen in the raw air, and an oxygen-containing oxygen that flows from the upper tower of the double rectification column A crude argon tower for concentrating argon, an argon purification device for removing oxygen in the crude argon, and purification of the product liquid argon by removing residual hydrogen and nitrogen from the modified argon from which oxygen has been removed. In an argon method for manufacturing a product liquid argon by cryogenic air separation apparatus having a argon column, when introducing the crude argon withdrawn from the crude argon column to the argon purification apparatus, withdrawn crude argon of the crude argon column Liquid crude argon is extracted from the mouth, introduced into the main heat exchanger through a crude argon extraction line and evaporated, and the evaporated crude argon gas is heated to room temperature.

  Moreover, the means which the argon manufacturing method by the cryogenic air separator which concerns on Claim 2 of this invention employ | adopted is the liquid extracted from the said crude argon tower in the argon manufacturing method by the cryogenic air separator of Claim 1. Before introducing the crude argon into the main heat exchanger via the crude argon extraction line, it is supercooled by a cooler using liquid nitrogen as a refrigerant.

  According to the argon production method by the cryogenic air separator according to claim 1 of the present invention, crude argon is extracted in liquid form from the crude argon outlet provided at a position of about 30 to 40 m from the ground of the crude argon tower. The liquid crude argon extracted can be pressurized with the liquid head of the liquid crude argon. Then, the liquid crude argon extracted and pressurized is introduced into the main heat exchanger and evaporated, and the evaporated high-pressure crude argon is removed with an argon purifier, and then supplied to the purified argon tower. Can do. Therefore, since the crude argon compressor which was necessary in the cryogenic air separation apparatus according to the conventional example is not necessary, it is possible to reduce the equipment cost and the running cost related to the cryogenic air separation apparatus.

  Moreover, according to the argon manufacturing method by the cryogenic air separation apparatus which concerns on Claim 1 of this invention, since crude argon is extracted in a liquid state, compared with the argon manufacturing method by the cryogenic air separation apparatus which concerns on a prior art example. Thus, the pressure of the crude argon at the crude argon outlet can be reduced. Therefore, the oxygen content in the crude argon can be reduced by increasing the number of rectification stages that can be equipped in the crude argon column. As the oxygen content in the crude argon decreases, the amount of hydrogen supplied to the argon purification device can be reduced, and thus the production cost of high-purity product liquid argon can be reduced.

According to the method for producing argon by the cryogenic air separation apparatus according to claim 2 of the present invention, as described above, if crude argon is extracted as liquid crude argon from the crude argon outlet of the crude argon tower, the liquid crude argon is Pressurization is performed with its own liquid head, but if it is partially vaporized by heat input while passing through the crude argon extraction line, it cannot be pressurized smoothly.
However, since the liquid crude argon is supercooled by a cooler using liquid nitrogen as a refrigerant and introduced into the main heat exchanger, vaporization of the liquid crude argon is prevented, and pressurization of the liquid crude argon is hindered. There is no such thing.

Hereinafter, a cryogenic air separation apparatus for carrying out an argon production method according to Embodiment 1 of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic system diagram of the cryogenic air separation device, FIG. 2 is an enlarged view of the main heat exchanger in FIG. 1, and FIG. 3 is an explanatory diagram of temperature distribution in the main heat exchanger that evaporates the crude argon liquid. By the way, the vertical axis in FIG. 3 is the axial heat exchange amount (× 10 ⁶ cal / h) from the low temperature end to the high temperature end of the main heat exchanger, and the horizontal axis is from the low temperature end to the high temperature end of the main heat exchanger. Temperature distribution (° C.). In addition, according to the cryogenic air separation apparatus that performs the argon production method, product nitrogen and product oxygen can be obtained, but since the purpose is to produce high-purity product argon, production of product nitrogen and product oxygen I'll omit the explanation of the method.

  The cryogenic air separation apparatus for carrying out the argon production method of the present invention includes a raw material air supply line 1 as shown in FIG. The raw air supply line 1 includes a raw air compressor 1a for compressing raw air sucked through a filter (not shown) to about 0.5 MPaG, and a precooling unit for cooling the compressed air to about 10 to 40 ° C. 1b, an adsorption tower unit 1c comprising a pair of adsorption towers arranged in parallel to alternately remove carbon dioxide and moisture in the cooled compressed air is interposed. A first raw material air supply line 3 and a second raw material air supply line 4 are branched from the raw material air supply line 1.

  The first raw material air supply line 3 is connected to the upper column 5a of the double rectifying column 5 including an upper column 5a having a main condenser 5c at the bottom and a lower column 5b via the main heat exchanger 2. It communicates with the middle part of the vertical direction. That is, a part of the compressed air from which carbon dioxide and moisture have been removed by the adsorption tower unit 1c is introduced into the middle in the vertical direction of the upper tower 5a of the double rectification tower 5 through the first raw material air supply line 3. It has become so. Between the branch portion of the first raw material air supply line 3 and the main heat exchanger 2, a blower 3a for compressing the raw material air and a cooler 3b for cooling the raw material air compressed by the blower 3a are interposed. Yes. Further, an expansion turbine 3c is provided between the main heat exchanger 2 and the upper tower 5a of the first raw material air supply line 3, and the cold for maintaining the main part of the deep air separation device at a low temperature. After being generated, the rectifying column 5 is supplied to the upper column 5a.

  The second raw material air supply line 4 communicates with the bottom of the lower column 5 b of the double rectification column 5 via the main heat exchanger 2. That is, the remainder of the compressed air from which carbon dioxide and moisture have been removed by the adsorption tower unit 1c flows through the second raw material air supply line 4 and is cooled to the vicinity of the air liquefaction temperature by the main heat exchanger 2, and then the lower tower 5b. It is designed to be introduced at the bottom. The cooling air cooled by the main heat exchanger 2 and introduced into the bottom of the lower tower 5b comes into contact with the flowing liquid and gradually becomes rich in nitrogen while rising in the lower tower 5b. It becomes high-purity nitrogen vapor at the top. This high-purity nitrogen vapor flows into the main condenser 5c installed at the bottom of the upper tower 5a, is cooled and liquefied, and is supplied as the reflux liquid of the lower tower 5b.

On the other hand, the liquid flowing down in the lower column 5b of the double rectifying column 5 gradually becomes oxygen-rich while flowing down, and at the bottom of the lower column 5b, oxygen-rich liquid air having an oxygen concentration of about 35 to 40% and Become.
This oxygen-rich liquid air is extracted from the bottom of the lower tower 5b through the liquid air extraction line 6, and after being cooled by the supercooler 7, is divided into two. A part of the oxygen-rich liquid air is supplied to a crude argon condenser 8a provided in the crude argon column 8 to evaporate, and is supplied to the middle in the vertical direction of the upper column 5a. The remaining oxygen-rich liquid air is decompressed while being in a liquid state and supplied to the middle part in the vertical direction of the upper tower 5a.

  Argon contained in the air at about 0.93% is concentrated to a concentration of about 8 to 12% in oxygen between the middle part and the lower part of the upper column 5a of the double rectification column 5. The vapor containing argon extracted from the middle portion of the upper column 5 a of the double rectification column 5 through the vapor extraction line 5 d is supplied to the bottom of the crude argon column 8. While the argon-containing vapor supplied to the bottom of the crude argon column 8 ascends in the crude argon column 8, the vapor comes into contact with the flowing liquid and gradually concentrates the argon. At the top, the steam is 95-99.8% argon (the balance is a small amount of oxygen and nitrogen).

  The vapor containing 95 to 99.8% argon is supplied to the crude argon condenser 8a, cooled and condensed into liquid crude argon, and refluxed to the lower part of the crude argon column 8 (below the crude argon condenser 8a). . A part of the liquid crude argon refluxed to the lower part of the crude argon column 8 is extracted from the crude argon extraction port 8b through a crude argon extraction line 9 communicating with the low temperature end of the main heat exchanger 2, and this crude argon extraction is performed. While flowing through line 9, the liquid crude argon head is pressurized. Assuming that the drop between the position of the crude argon outlet 8b and the low temperature end of the main heat exchanger 2 is, for example, 30 m, the liquid crude argon is pressurized to about 0.42 MPaG. The liquid crude argon pressure of about 0.42 MPaG is then evaporated and heated to the normal temperature in the main heat exchanger 2, the pressure loss in the argon purification device 10, the pressure loss in the modified argon supply line 11, the purified argon tower The pressure is sufficient to cover all of the pressure loss and the like due to the rectifying operation in No. 12.

In addition, as shown in FIG. 4 of the general explanatory diagram of the conventional evaporation method of liquid argon, the pressurized liquid argon is supplied with air compressed by a pressurizing compressor or nitrogen compressed by a compressor (not shown). In general, it is supplied to the liquid argon evaporator 32 and evaporated, and then supplied to the argon purification apparatus 10 via the main heat exchanger 2. However, since the boiling point of argon is higher than that of air or nitrogen, when air or nitrogen is used to evaporate argon, it is necessary to increase the pressure of air or nitrogen. Incidentally, an outline of the pressure of argon and the pressure of air necessary for evaporating liquid argon at this pressure is shown in Table 1 below.

  As well understood from Table 1 above, air with a pressure of 1.0 MPaG or more is required to evaporate liquid crude argon pressurized to about 0.42 MPaG. However, such a high-pressure air does not exist in a general cryogenic air separation apparatus used for producing argon of the present invention. Therefore, in order to employ such an evaporation method, a booster compressor that compresses about 0.5 MPaG of raw material air to 1.0 MPaG or more is necessary.

  However, in the argon production method using the cryogenic air separation device according to the first embodiment of the present invention, high pressure air is usually introduced by intentionally introducing liquid crude argon into the main heat exchanger 2 used only for heat exchange between gases. Liquid crude argon is evaporated without using it. This is because the raw air, which is about 50 to 200 times larger than the liquid crude argon, is introduced into the main heat exchanger 2 as a high-temperature side fluid. This is because it is possible to evaporate with 5 MPaG of air.

Each fluid flowing through the main heat exchanger 2 is as shown in FIG. 2, and an example of the temperature distribution in the main heat exchanger 2 when liquid crude argon is evaporated by the main heat exchanger 2 is shown in FIG. It is as follows.
There is a temperature difference of 2-8 ° C. at each temperature level, and the liquid crude argon can be sufficiently evaporated. The flow rate and pressure of each fluid shown in FIG. 3 are as follows.
(1) Air A (G. Air): 8,500 Nm ^{3 /} h, 0.5 MPaG
(2) Air B (T. Air): 1,500 Nm ^{3 /} h, 0.7 MPaG
(3) Nitrogen (GN): 2,000 Nm ^{3 /} h, 0.02 MPaG
(4) Oxygen (GO): 2,000 Nm ^{3 /} h, 0.03 MPaG
(5) Waste nitrogen (WN): 5,950 Nm ^{3 /} h, 0.02 MPaG
(6) Liquid crude argon (Cr.Ar): 50 Nm ^{3 /} h, 0.3 MPaG
(7) Modified argon (Co.Ar): 50 Nm ^{3 /} h, 0.2 MPaG

  The liquid crude argon that has been extracted from the argon outlet 8b of the crude argon column 8 and flows through the crude argon extraction line 9 is subjected to heat exchange in the main heat exchanger 2 in which the fluids of the above conditions are flowing. Evaporates to gaseous crude argon. And the gaseous crude argon heated to the normal temperature by the main heat exchanger 2 is supplied to the argon purification apparatus 10, and the oxygen content in gaseous gaseous argon is removed. Next, the modified argon from which oxygen content has been removed flows through the modified argon supply line 11, is again passed through the main heat exchanger 2, is cooled to the vicinity of its liquefaction temperature, and is supplied to the center of the purified argon column 12. In the purified argon column 12, nitrogen and the like are removed from the supplied modified argon to obtain high-purity product liquid argon, which is extracted from the bottom of the purified argon column 12 and delivered to the customer.

The line passing through the supercooler 7 and the main heat exchanger 2 from the top of the upper column 5a of the double rectification column 5 is a GN discharge line 13 for extracting nitrogen products, and the upper column of the double rectification column 5 A line passing through the main heat exchanger 2 from the lower part of 5a is a GO discharge line 14 for extracting an oxygen product.
In addition, a waste nitrogen extraction line 15 is connected to the upper portion of the upper column 5a of the double rectification column 5 in the same manner as in a general conventional example, and the waste nitrogen extracted through the waste nitrogen extraction line 15 is connected. Is heated via the main heat exchanger 2. A part of the heated waste nitrogen is utilized for adsorbent regeneration of the adsorption tower unit 1c, and the rest is released into the atmosphere.

  Hereinafter, an operation mode of the argon production method by the cryogenic air separation device according to the first embodiment of the present invention will be described. That is, in the case of the argon production method using the cryogenic air separation device according to the first embodiment of the present invention, as described above, the crude argon outlet provided at a position about 30 to 40 m above the ground of the crude argon tower 8. Crude argon is extracted from 8b as liquid crude argon and introduced into the main heat exchanger 2.

  Therefore, even if the pressure of the crude argon at the crude argon outlet 8b is low, the liquid crude argon can be reliably extracted from the crude argon outlet 8b, and the liquid crude argon extracted can be added by its own liquid head. Can be pressed. Then, the liquid crude argon extracted and pressurized is introduced into the main heat exchanger 2 and evaporated, heated to room temperature and introduced into the argon purifier 10. After removing oxygen from the argon gas, it can be supplied to the purified argon column 12. Therefore, according to the method for producing argon by the cryogenic air separation device according to the first embodiment of the present invention, the crude argon compressor that is necessary in the conventional cryogenic air separation device is not required. It is possible to obtain an excellent effect that the equipment cost and running cost related to the apparatus can be reduced.

  Moreover, according to the argon manufacturing method by the cryogenic air separator which concerns on form 1 of this invention, since crude argon is extracted as liquid crude argon as above-mentioned, argon by the cryogenic air separator which concerns on a prior art example Compared with the manufacturing method, the pressure of the crude argon at the crude argon outlet 8b can be reduced. Therefore, the oxygen content in the crude argon can be reduced by increasing the number of rectification stages that can be equipped in the crude argon column. As the oxygen content in the crude argon is lowered, the amount of hydrogen supplied to the argon purification apparatus 10 can be reduced, so that it is possible to reduce the production cost of high-purity product liquid argon. be able to.

  A cryogenic air separation apparatus according to the second embodiment of the present invention that performs an argon production method will be described with reference to the accompanying drawings. FIG. 5 is a schematic system diagram of the cryogenic air separation device. The difference between the present embodiment 2 and the above embodiment 1 is that a cooler is interposed in the crude argon extraction line, and other than that, the configuration is exactly the same as that of the above embodiment 1, so The same reference numerals are assigned and different points will be described.

  That is, the cryogenic air separation apparatus according to the second embodiment of the present invention is configured so that the crude argon extraction line 9 communicates with the argon purification apparatus 10 via the main heat exchanger 2 from the crude argon extraction port 8b of the crude argon column 8. A cooler 16 using liquid nitrogen as a refrigerant is interposed downstream of the crude argon outlet 8b.

  Therefore, according to the argon production method by the cryogenic air separation device according to the second embodiment of the present invention, since a crude argon compressor is unnecessary, the same effect as the first embodiment can be obtained, and in addition, it will be described later. An effect can also be obtained. That is, according to the argon production method using the cryogenic air separation device according to the second embodiment of the present invention, as described above, crude argon is extracted in liquid form from the crude argon extraction port 8b of the crude argon column 8 and the crude argon liquid is pressurized. However, if it is partially vaporized by heat input while passing through the inside of the crude argon extraction line 9, it becomes impossible to pressurize smoothly. However, since the liquid crude argon extracted in a liquid state is supercooled by the cooler 16 using liquid nitrogen as a refrigerant and introduced into the main heat exchanger 2, vaporization of the liquid crude argon is prevented, and the liquid crude argon is prevented. There will be no trouble in pressurizing argon.

  By the way, in the above forms 1 and 2, only the case where argon was manufactured with a chilled air separator was explained as an example. However, according to this cryogenic air separation device, not only the production of argon, but also oxygen products and nitrogen products can be produced in parallel with the production of argon. While stopping production, oxygen products and nitrogen products can also be produced.

  Further, when product nitrogen is produced by this cryogenic air separation device, it is rectified in the double rectification column 5 as shown in FIG. 6 of the schematic system diagram of the cryogenic air separation device according to Embodiment 3 of the present invention. A part of the nitrogen can be extracted as liquid nitrogen. More specifically, a part of the rectifying column 5 is extracted as liquid nitrogen through the liquid nitrogen discharge line 23, and is sent to the main heat exchanger 2 by the liquid nitrogen pump 23a to be evaporated to form gaseous nitrogen. On the other hand, the remainder is extracted as gaseous nitrogen through the GN discharge line 13, sent to the main heat exchanger 2, heated, compressed by the nitrogen compressor 13 a, merged with the gaseous nitrogen, and supplied to the product nitrogen supply destination By adopting such a configuration, the power cost of the nitrogen compressor 13a can be reduced.

  Further, when product oxygen is produced by this cryogenic air separator, as shown in FIG. 7 of the schematic system diagram of the cryogenic air separator according to Embodiment 4 of the present invention, the product oxygen is rectified in the double rectification column 5. A part of the oxygen can be extracted as liquid oxygen. More specifically, a part of the rectifying column 5 is extracted as liquid oxygen through the liquid oxygen discharge line 24, and sent to the main heat exchanger 2 by the liquid oxygen pump 24a to be evaporated to be gaseous oxygen. On the other hand, the remainder is extracted as gaseous oxygen through the GO discharge line 14 and sent to the main heat exchanger 2 to be heated, compressed by the oxygen compressor 14a, merged with the gaseous oxygen, and supplied to the product oxygen supply destination. By adopting such a configuration, the power cost of the oxygen compressor 14a can be reduced.

  As described above, since the cryogenic air separation devices in the above-described forms 1 to 4 are only specific examples, the design of the cryogenic air separation device can be freely changed without departing from the technical idea of the present invention. is there.

1 is a schematic system diagram of a cryogenic air separator that performs an argon production method according to Embodiment 1 of the present invention. FIG. It is an enlarged view of the main heat exchanger of the cryogenic air separator which concerns on Embodiment 1 of this invention and implements the argon manufacturing method. It is temperature distribution explanatory drawing in the main heat exchanger which concerns on Embodiment 1 of this invention and evaporates a rough | crude argon liquid. It is explanatory drawing of the general evaporation method of the conventional liquid argon. It is a typical systematic diagram of the cryogenic air separation apparatus which concerns on Embodiment 2 of this invention and implements the argon manufacturing method. It is a typical systematic diagram of the cryogenic air separation apparatus which concerns on Embodiment 3 of this invention and implements the argon manufacturing method. It is a typical systematic diagram of the cryogenic air separation apparatus which concerns on Embodiment 4 of this invention and implements the argon manufacturing method. It is a typical system explanatory drawing of the common cryogenic air separation apparatus which concerns on the prior art example which implements an argon manufacturing method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Raw material air supply line, 1a ... Raw material air compressor, 1b ... Pre-cooling unit, 1c ... Adsorption tower unit 2 ... Main heat exchanger 3 ... First raw material air supply line, 3a ... Blower, 3b ... Cooler, 3c ... Expansion Turbine 4 ... Second raw material air supply line 5 ... Double rectification tower, 5a ... Upper tower, 5b ... Lower tower, 5c ... Main condenser, 5d ... Vapor extraction line 6 ... Liquid air extraction line 7 ... Supercooler 8 ... Rough argon tower, 8a ... Rough argon condenser, 8b ... Rough argon outlet 9 ... Rough argon outlet line 10 ... Argon purification device 11 ... Modified argon supply line 12 ... Purified argon tower 13 ... GN discharge line, 13a ... Nitrogen compressor DESCRIPTION OF SYMBOLS 14 ... GO discharge line, 14a ... Oxygen compressor 15 ... Waste nitrogen extraction line 16 ... Cooler 23 ... Liquid nitrogen discharge line, 23a ... Liquid nitrogen pump 24 ... Liquid oxygen Out of line, 24a ... liquid oxygen pump

Claims (2)

A raw material air compressor that compresses the raw material air, a precooling unit that cools the compressed air discharged from the raw material air compressor to a temperature of about 10 to 40 ° C., carbon dioxide in the compressed air cooled by the precooling unit, and Adsorption tower unit that removes moisture, main heat exchanger that cools the raw air purified by this adsorption tower unit to a temperature near its liquefaction, and a double rectification tower that rectifies and separates nitrogen and oxygen in the raw air And a crude argon tower for concentrating argon in oxygen containing argon flowing in from the upper column of the double rectification tower, an argon purification apparatus for removing oxygen in the crude argon, and a residual from the modified argon from which oxygen has been removed. in an argon method for manufacturing a product liquid argon by cryogenic air separation unit that includes a purification argon column for a product liquid argon to remove hydrogen, nitrogen or the like, the coarse Al When the crude argon extracted from the column is introduced into the argon purifier, liquid crude argon is extracted from the crude argon outlet of the crude argon tower and introduced into the main heat exchanger via the crude argon extraction line. A method for producing argon using a cryogenic air separation apparatus, wherein the evaporated crude argon gas is heated to room temperature.   The liquid crude argon extracted from the crude argon tower is supercooled by a cooler using liquid nitrogen as a refrigerant before being introduced into the main heat exchanger through the crude argon extraction line. 2. A method for producing argon using the cryogenic air separation device according to 1.

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