JP2018169051A - Air separation method and air separation device - Google Patents

Abstract

The present invention provides an air separation method and an air separation device capable of increasing the pressure difference between the pressure in a high pressure column and the pressure in an indirect heat exchanger outer cylinder.
An air separation method includes the step of adiabatically expanding a part of a high-pressure nitrogen gas fluid or a part of a high-pressure raw material air fluid or the high-pressure nitrogen-enriched air fluid.
[Selection] Figure 1

Description

  The present invention relates to an air separation method and an air separation device.

  An air separation method and an air separation device are known in which air is separated into nitrogen, oxygen, and argon by a cryogenic separation method. Since such air separation devices are generally large, attempts have been made to reduce the installation area and the like.

FIG. 6 is a system diagram showing a schematic configuration of a conventional air separation device 600.
The air separation device 600 disclosed in Patent Document 1 includes a high-pressure column 4 having an internal pressure of about 860 kPaA, a low-pressure column 5 having an internal pressure of about 130 kPaA, an argon column 6 having an internal pressure of about 230 kPaA, and a high-pressure column 4. It has a liquid pump 34 for feeding the high-pressure oxygen-enriched liquefied oxygen therein to the indirect heat exchanger 7 for introduction.

  FIG. 7 a is a schematic diagram showing the configuration and arrangement of a conventional air separation device 600. As shown in FIG. 7a, in the air separation device 600, in order to reduce the installation area, the argon column 6 is disposed above the high-pressure column 4, and further the second indirect heat exchanger 8 is accommodated above it. A second indirect heat exchanger outer cylinder 14 is disposed, and a first indirect heat exchanger outer cylinder 13 that houses the first indirect heat exchanger 7 is disposed above the low pressure column 5. Further, a liquid pump 34 for sending high-pressure oxygen-enriched liquefied oxygen from the bottom of the high-pressure tower 4 to the first indirect heat exchanger outer cylinder 13 is disposed below the high-pressure tower 4.

  Patent Document 1 discloses an air separation method using such an air separation device 600. In the conventional air separation method, the high-pressure oxygen-enriched liquefied oxygen at the bottom of the high-pressure column 4 is sent by the liquid pump 34 via the pipelines 61 and 62, and the first indirect heat exchanger outer cylinder 13. To be introduced. The high-pressure oxygen-enriched liquefied oxygen introduced into the first indirect heat exchanger outer cylinder 13 is evaporated and evaporated by the indirect heat exchanger 7 to become medium-pressure oxygen-enriched air. The medium-pressure oxygen-enriched air is heated by the main heat exchanger 11 via the pipe line 651 and then adiabatically expanded by the expansion turbine 10. The adiabatically expanded fluid is introduced into the low-pressure column 5 through a pipe line 652 (Patent Document 1).

JP, 2006-008778, A

However, in the air separation device 600 disclosed in Patent Document 1, the pressure in the high-pressure column 4 is about 860 kPaA, the pressure in the first indirect heat exchanger outer cylinder 13 is about 600 kPaA, and the inside of the high-pressure column 4 And the pressure in the first indirect heat exchanger outer cylinder 13 were as small as about 260 kPa. Therefore, in order to arrange the first indirect heat exchanger outer cylinder 13 above the low pressure column 5 as in the air separation device 600 shown in FIG. 7, the high pressure oxygen-enriched liquefied oxygen is supplied from the bottom of the high pressure column 4 to the first. It is necessary to provide the air separation device 600 with the liquid pump 34 introduced into the indirect heat exchanger outer cylinder 13.
Therefore, in the air separation device 600, extra equipment cost, space, power, and the like for installing the liquid pump 34 are generated.

  The present invention has been made in view of the above circumstances, and an air separation method and an air separation device capable of increasing the pressure difference between the pressure in the high-pressure tower and the pressure in the indirect heat exchanger outer cylinder as compared with the conventional one. It is an issue to provide.

The present invention has the following configuration.
The invention according to claim 1 is an air separation method for separating raw material air by a cryogenic separation method, wherein the raw material air is compressed, purified and cooled to obtain a high pressure raw material air fluid, and the high pressure raw material A high-pressure separation step of separating the air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation; and a part of the high-pressure nitrogen gas fluid is adiabatically expanded to An adiabatic expansion step to be generated, the cold fluid and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid are indirectly heat-exchanged, and the cold fluid is condensed and liquefied. A first indirect heat exchange step of obtaining a low pressure liquefied gas fluid and evaporating and evaporating the low pressure oxygen enriched liquefied air fluid to obtain a low pressure oxygen enriched air fluid; and passing the low pressure oxygen enriched air fluid through an expansion turbine Without A low-pressure separation step for separating the low-pressure nitrogen gas fluid, the low-pressure liquefied oxygen fluid, and the low-pressure argon-enriched liquefied oxygen fluid by hot distillation, and pressurizing the low-pressure argon-enriched liquefied oxygen fluid; Argon separation step of separating into an intermediate pressure liquefied oxygen fluid, an indirect heat exchange between the argon gas fluid and the low pressure liquefied oxygen fluid, condensing and liquefying the argon gas fluid to obtain a liquefied argon fluid, and the low pressure liquefaction A second indirect heat exchange step of evaporating and vaporizing the oxygen fluid to obtain a low-pressure oxygen gas fluid; indirect heat exchange between the high-pressure nitrogen gas fluid and the medium-pressure liquefied oxygen fluid; and condensing and liquefying the high-pressure nitrogen gas fluid A third indirect heat exchange step of obtaining a high-pressure liquefied nitrogen fluid and evaporating and vaporizing the medium-pressure liquefied oxygen fluid to obtain a medium-pressure oxygen gas fluid; A first product recovery step of deriving at least one of the liquefied argon fluids or at least one of the argon gas fluids not liquefied in the second indirect heat exchange step as product argon gas; and the low-pressure liquefaction A second product in which at least one kind of fluid is derived as a product from a part of an oxygen fluid, a part of the medium pressure liquefied oxygen fluid, a part of the high pressure nitrogen gas fluid, or a part of the high pressure liquefied nitrogen fluid. And a recovery step.

  The invention according to claim 2 is an air separation method for separating raw material air by a cryogenic separation method, wherein the raw material air is compressed, purified and cooled to obtain a high pressure raw material air fluid, and the high pressure raw material A high-pressure separation step for separating the air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation; and a part of the high-pressure feed air fluid or the high-pressure nitrogen-enriched air An adiabatic expansion step in which any one of the fluids is adiabatically expanded to generate a cold fluid, and the cold fluid and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid. Heat exchange, condensing and liquefying the cold fluid to obtain a low pressure liquefied gas fluid, and evaporating and vaporizing the low pressure oxygen enriched liquefied air fluid to obtain a low pressure oxygen enriched air fluid; Low pressure oxygen rich A low-pressure separation step for separating the air fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through an expansion turbine; and pressurizing the low-pressure argon-enriched liquefied oxygen fluid After that, an argon separation step for separating the argon gas fluid and the medium-pressure liquefied oxygen fluid by low-temperature distillation, the argon gas fluid and the low-pressure liquefied oxygen fluid are indirectly heat-exchanged, and the argon gas fluid is condensed and liquefied. Obtaining a liquefied argon fluid, evaporating and vaporizing the low-pressure liquefied oxygen fluid to obtain a low-pressure oxygen gas fluid; indirect heat exchange between the high-pressure nitrogen gas fluid and the medium-pressure liquefied oxygen fluid; The high pressure nitrogen gas fluid is condensed and liquefied to obtain a high pressure liquefied nitrogen fluid, and the intermediate pressure liquefied oxygen fluid is evaporated and vaporized to obtain a medium pressure oxygen gas fluid. Among the argon gas fluid, a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid that has not been liquefied in the second indirect heat exchange step, at least one argon fluid is used as product argon gas At least one of a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid. A second product recovery step of deriving at least one fluid as a product.

  The invention according to claim 3 is an air separation device that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools the raw material air to obtain a high-pressure raw material air fluid, and the high pressure A high-pressure column for subjecting the raw air fluid to low-temperature distillation to rectify and separate into a high-pressure nitrogen gas fluid at the top of the column, a high-pressure nitrogen-enriched air fluid at the middle and a high-pressure oxygen-enriched liquefied air fluid at the bottom, and the high-pressure nitrogen gas Indirect heat of an expansion turbine that adiabatically expands a part of the fluid to generate a cold fluid, the cold fluid, and a low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid A first indirect heat exchanger that condenses and liquefies the cryogenic fluid to produce a low pressure liquefied gas fluid and evaporates and vaporizes the low pressure oxygen enriched liquefied air fluid to produce a low pressure oxygen enriched air fluid; The low-pressure oxygen-enriched air fluid A low pressure column that separates into a low pressure nitrogen gas fluid, a low pressure liquefied oxygen fluid, and a low pressure argon enriched liquefied oxygen fluid by low temperature distillation without going through the expansion turbine, and after pressurizing the low pressure argon enriched liquefied oxygen fluid, An argon tower that separates into an argon gas fluid and an intermediate-pressure liquefied oxygen fluid by low-temperature distillation, indirectly exchanges heat between the argon gas fluid and the low-pressure liquefied oxygen fluid, and condenses and liquefies the argon gas fluid to produce a liquefied argon fluid. And generating a low pressure oxygen gas fluid by evaporating the low pressure liquefied oxygen fluid, indirectly exchanging heat between the high pressure nitrogen gas fluid and the medium pressure liquefied oxygen fluid, A third indirect heat that condenses and liquefies the nitrogen gas fluid to generate a high-pressure liquefied nitrogen fluid and evaporates and vaporizes the intermediate-pressure liquefied oxygen fluid to generate an intermediate-pressure oxygen gas fluid At least one type of argon fluid is derived as product argon gas from the converter and a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid not liquefied by the second indirect heat exchanger At least one of a first product recovery line, a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid And a second product recovery line for deriving a fluid of a seed or more as a product.

  The invention according to claim 4 is an air separation device that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools raw material air to obtain a high pressure raw material air fluid, and the high pressure A high-pressure column for rectifying and separating a raw air fluid into a high-pressure nitrogen gas fluid at the top of the tower, a high-pressure nitrogen-enriched air fluid at the middle, and a high-pressure oxygen-enriched liquefied air fluid at the bottom of the tower; An expansion turbine that generates a cold fluid by adiabatically expanding either a part of the fluid or the high-pressure nitrogen-enriched air fluid, the cold fluid, and the high-pressure oxygen-enriched liquefied air fluid obtained by depressurizing Indirect heat exchange with the low-pressure oxygen-enriched liquefied air fluid, condensing and liquefying the cryogenic fluid to generate a low-pressure liquefied gas fluid, and evaporating and evaporating the low-pressure oxygen-enriched liquefied air fluid First to generate fluid A low-pressure column that separates the low-pressure oxygen-enriched air fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through the expansion turbine; After pressurizing the low-pressure argon-enriched liquefied oxygen fluid, an indirect heat exchange is performed between the argon column that is separated into an argon gas fluid and an intermediate-pressure liquefied oxygen fluid by low-temperature distillation, and the argon gas fluid and the low-pressure liquefied oxygen fluid. A second indirect heat exchanger for condensing and liquefying the argon gas fluid to produce a liquefied argon fluid and evaporating and vaporizing the low pressure liquefied oxygen fluid to produce a low pressure oxygen gas fluid; the high pressure nitrogen gas fluid; Indirect heat exchange with medium pressure liquefied oxygen fluid, condensing and liquefying the high pressure nitrogen gas fluid to produce high pressure liquefied nitrogen fluid and evaporating the medium pressure liquefied oxygen fluid A third indirect heat exchanger that generates a medium pressure oxygen gas fluid, a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid that has not been liquefied by the second indirect heat exchanger. Among them, a first product recovery line for deriving at least one kind of argon fluid as product argon gas, a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, and a part of the high-pressure nitrogen gas fluid Or it is a 2nd product collection | recovery pipe | tube which derives | leads-out at least 1 or more types of fluid as a product among some high-pressure liquefied nitrogen fluids.

  According to the air separation method and the air separation apparatus of the present invention, the pressure in the indirect heat exchanger outer cylinder is about 130 kPaA, the pressure in the high pressure column is about 860 kPaA, and the pressure difference between these is about 730 kPa. Can be bigger. Therefore, an indirect heat exchanger can be arranged above the low-pressure column without the need for a liquid pump for introducing high-pressure oxygen-enriched liquefied oxygen from the bottom of the high-pressure column into the indirect heat exchanger. And power can be reduced.

FIG. 1 is a system diagram showing a schematic configuration of an air separation device according to a first embodiment of the present invention. FIG. 2 is a system diagram showing a schematic configuration of an air separation device according to a second embodiment of the present invention. FIG. 3 is a system diagram showing a schematic configuration of an air separation device according to a third embodiment of the present invention. FIG. 4 is a system diagram showing a schematic configuration of an air separation device according to a fourth embodiment of the present invention. FIG. 5 is a system diagram showing a schematic configuration of an air separation device according to a fifth embodiment of the present invention. FIG. 6 is a system diagram showing a schematic configuration of a conventional air separation device. FIG. 7a is a schematic diagram showing the configuration and arrangement of a conventional air separation device. FIG. 7 b is a schematic diagram showing the configuration and arrangement of the air separation device of the present invention.

  Embodiments to which the present invention is applied will be described below in detail with reference to the drawings. The drawings used in the following description are for explaining the configuration of the embodiment of the present invention, and the size, thickness, dimensions, and the like of each part shown in the drawings are different from the dimensional relationship of an actual air separation device. There is a case.

[First Embodiment]
The air separation device of the first embodiment is an air separation device that separates raw material air by a cryogenic separation method, and is a raw material air pretreatment facility that compresses, purifies, and cools raw material air to obtain a high-pressure raw material air fluid. The high pressure raw material air fluid is subjected to low temperature distillation to rectify and separate the high pressure nitrogen gas fluid at the top of the tower, the high pressure nitrogen enriched air fluid at the middle, and the high pressure oxygen enriched liquefied air fluid at the bottom of the tower; An expansion turbine that adiabatically expands a high-pressure nitrogen-enriched air fluid to generate a cryogenic fluid, the cryogenic fluid, and a low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid. A first indirect heat exchanger that performs indirect heat exchange to condense and liquefy the cold fluid to generate a low-pressure liquefied gas fluid and evaporate and vaporize the low-pressure oxygen-enriched liquefied air fluid to generate a low-pressure oxygen-enriched air fluid And the low-pressure oxygen-enriched sky A low-pressure column that separates the fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through the expansion turbine; and the low-pressure argon-enriched liquefied oxygen fluid was pressurized Thereafter, an argon tower that is separated into an argon gas fluid and an intermediate-pressure liquefied oxygen fluid by low-temperature distillation, and the argon gas fluid and the low-pressure liquefied oxygen fluid are indirectly heat-exchanged to condense and liquefy the argon gas fluid to liquefy argon. A second indirect heat exchanger that generates a fluid and evaporates and vaporizes the low-pressure liquefied oxygen fluid to generate a low-pressure oxygen gas fluid; and indirectly heat-exchanges the high-pressure nitrogen gas fluid and the medium-pressure liquefied oxygen fluid; The high-pressure nitrogen gas fluid is condensed and liquefied to generate a high-pressure liquefied nitrogen fluid, and the medium-pressure liquefied oxygen fluid is evaporated and vaporized to generate a medium-pressure oxygen gas fluid. Among the indirect heat exchanger and a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid that has not been liquefied by the second indirect heat exchanger, at least one argon fluid is used as product argon gas. A first product recovery line derived as a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid or a part of the high-pressure liquefied nitrogen fluid, And a second product recovery conduit for deriving at least one fluid as a product.

FIG. 1 is a system diagram showing a schematic configuration of an air separation device according to a first embodiment of the present invention.
In the description of the first embodiment, “low pressure” refers to a pressure that is equal to or higher than the pressure of the product low-pressure nitrogen gas and lower than the operating pressure of the argon tower 6. “Medium pressure” refers to a pressure that is equal to or higher than the operating pressure of the argon tower 6 and lower than the pressure of the product high-pressure nitrogen gas. “High pressure” means a pressure higher than the pressure of the product high-pressure nitrogen gas.
As shown in FIG. 1, the air separation device 100 according to the first embodiment includes a first raw material air compressor 1, a purifier 2, a second raw material air compressor 3, a high pressure column 4, and a low pressure column 5. The argon tower 6, the first indirect heat exchanger 7, the second indirect heat exchanger 8, the third indirect heat exchanger 9, the expansion turbine 10, the main heat exchanger 11, and the subcooler 12 The first indirect heat exchanger outer cylinder 13, the second indirect heat exchanger outer cylinder 14, the pressure reducing valves 21 to 27, the liquid pumps 31, 32, 33, the first product recovery line 46, the second It has product recovery pipelines 41, 44, 45, third product recovery pipelines 42, 43, and pipelines 50-63, 65-79, 641, 642.

  The air separation apparatus 100 has a raw material air pretreatment facility that compresses, purifies, and cools raw material air to obtain a high-pressure raw material air fluid. The raw material air pretreatment equipment includes a first raw material air compressor 1, a purifier 2, pipe lines 51 and 52 that pass through the main heat exchanger 11, and a second raw material air compressor 3.

  The first raw material air compressor 1 is provided in the pipe line 50. The first raw material air compressor 1 is connected to a supply source (not shown) of air containing oxygen, nitrogen, and argon (hereinafter also referred to as “raw air”) via a pipe line 50. The first source air compressor 1 compresses source air supplied from a source air source (not shown).

  One end of the pipe 50 is connected to a source air supply source (not shown), and the other end is branched into a pipe 51 and a pipe 52. The pipe line 50 introduces the raw material air compressed by the first raw material air compressor 1 into the purifier 2 described later.

  The purifier 2 is provided between the branch position of the pipe 51 and the pipe 52 in the pipe 50 and the first raw material air compressor 1. The purifier 2 removes water and impurities such as carbon dioxide contained in the raw material air compressed by the first raw material air compressor 1.

The second raw material air compressor 3 is provided between the main heat exchanger 11 and a position of the pipe 52 that branches from the pipe 50. The second raw material air compressor 3 compresses the remainder of the raw material air from which impurities have been removed by the purifier 2.
The pressure reducing valve 21 is provided between the first raw material air compressor 1 and the high pressure tower 4 in the pipe line 52. The pressure reducing valve 21 depressurizes the raw material air cooled by the main heat exchanger 11.

  The main heat exchanger 11 includes a part of the pipe lines 51 and 52, a part of pipe lines 641 and 642, which will be described later, a part of the second product recovery pipe line 41, and a third product recovery pipe line 42 and 43. It is arranged so that a part passes. The main heat exchanger 11 indirectly exchanges heat between the fluids flowing through the pipelines 51, 52, 641, 642, the second product recovery pipeline 41, and the third product recovery pipelines 42, 43, Cool or raise the temperature of the fluid.

The pipe 51 is connected to the lower part of the high-pressure tower 4. A part of the pipe line 51 passes through the main heat exchanger 11. In the pipe line 51, a part of the raw material air from which impurities have been removed by the purifier 2 is cooled by the main heat exchanger 11 and introduced into the high pressure column 4 as the first high pressure raw material air fluid.
The pipe line 52 is connected to the middle part of the high-pressure tower 4. A part of the pipeline 52 passes through the main heat exchanger 11. The pipe line 52 cools the raw material air compressed by the second raw material air compressor 3 with the main heat exchanger 11, depressurizes the cooled raw material air with the pressure reducing valve 21, 2 as a high-pressure raw material air fluid.

The high-pressure tower 4 is connected to one ends of the pipelines 51, 52, 53, 57, 61, and 641, respectively.
The high-pressure column 4 is a low-temperature distillation of the first and second high-pressure feed air fluids into a high-pressure nitrogen gas fluid at the top of the column, a high-pressure nitrogen-enriched air fluid at the middle, and a high-pressure oxygen-enriched liquefied air fluid at the bottom. Rectification separation. Specifically, the high-pressure tower 4 performs low-temperature distillation of the first and second high-pressure raw air fluids introduced from the pipelines 51 and 52 and the fluid introduced from the pipeline 57 to obtain a high-pressure nitrogen gas fluid. And a high-pressure nitrogen-enriched air fluid and a high-pressure oxygen-enriched liquefied air fluid. The high-pressure column 4 is provided with a rectification stage (shelf), a regular filler, an irregular filler, or the like.

  Specifically, when the first high-pressure raw material air fluid introduced into the high-pressure tower 4 rises in the high-pressure tower 4, the reflux liquid of the high-pressure tower 4 (that is, a part of the high-pressure liquefied nitrogen fluid described later, And the second high-pressure feed air fluid), and the composition of the low-boiling components increases. On the other hand, when the high-pressure liquefied nitrogen fluid that is the reflux liquid of the high-pressure tower 4 and the second high-pressure raw material air fluid descend in the high-pressure tower 4, the first high-pressure raw air fluid that is the rising gas of the high-pressure tower 4 Counter-current contact and increase the composition of high boiling point components.

A high-pressure nitrogen gas fluid is generated at the top of the high-pressure column 4. The nitrogen concentration of the high pressure nitrogen gas fluid is higher than the nitrogen concentration of the feed air, and the oxygen concentration of the high pressure nitrogen gas fluid is lower than the oxygen concentration of the feed air. The high pressure nitrogen gas fluid is led to the pipe line 53.
A high-pressure nitrogen-enriched air fluid is generated in the middle part of the high-pressure column 4. The nitrogen concentration of the high pressure nitrogen enriched air fluid is higher than the nitrogen concentration of the high pressure oxygen enriched liquefied air fluid. High pressure nitrogen-enriched air fluid is led to line 641.
A high-pressure oxygen-enriched liquefied air fluid is generated at the bottom of the high-pressure column 4. The high pressure oxygen enriched liquefied air fluid is led to line 61.

One end of the conduit 53 is connected to the upper portion of the high-pressure tower 4, and the other end is branched into a conduit 54 and a conduit 55.
The pipeline 54 is connected to the second product recovery pipeline 41. The pipe 54 leads a part of the high-pressure nitrogen gas fluid led out to the pipe 53 to the second product recovery pipe 41.
The pipe 55 is connected to the fluid passage inlet of the third indirect heat exchanger 9. The pipeline 55 introduces the remainder of the high-pressure nitrogen gas fluid led out to the pipeline 53 to the third indirect heat exchanger 9.
The second product recovery pipeline 41 is connected to a pipeline 54 branched from the pipeline 53. A part of the second product recovery pipe 41 passes through the main heat exchanger 11. The second product recovery pipe 41 is heated by indirectly exchanging the high-pressure nitrogen gas fluid with the main heat exchanger 11. The second product recovery conduit 41 is a conduit for recovering the high-pressure nitrogen gas fluid led out to the conduit 54 as product high-pressure nitrogen gas.

One end of the conduit 57 is connected to the upper portion of the high-pressure tower 4, and the other end is branched into a conduit 56 and a conduit 58. The pipe 56 is connected to the fluid passage outlet of the third indirect heat exchanger 9. The pipe line 57 introduces a part of the high-pressure liquefied nitrogen fluid generated in the third indirect heat exchanger 9 to the upper part of the high-pressure column 4.
The pipe 58 is further branched into a pipe 59 and a pipe 60. A part of the pipe 58 passes through the supercooler 12. The pipe 58 cools the remainder of the high-pressure liquefied nitrogen fluid generated by the third indirect heat exchanger 9 by the supercooler 12.
The pipe 59 is connected to the upper part of the low pressure column 5. The pressure reducing valve 26 is provided in the pipeline 59. The pressure reducing valve 26 depressurizes the high-pressure liquefied nitrogen fluid cooled by the subcooler 12. In the pipe line 59, a part of the high-pressure liquefied nitrogen fluid led out to the pipe line 58 is depressurized by the pressure reducing valve 26 and introduced into the top of the low-pressure column 5 as a low-pressure liquefied nitrogen fluid. The low-pressure liquefied nitrogen fluid introduced into the low-pressure column 5 becomes the reflux liquid of the low-pressure column 5.
The pipeline 60 is connected to the second product recovery pipeline 44. The pipeline 60 is a pipeline branched from the pipeline 58. The second product recovery conduit 44 is a conduit for recovering the remainder of the high-pressure liquefied nitrogen fluid led to the conduit 58 as product liquefied nitrogen.

One end of the pipe 61 is connected to the bottom of the high-pressure tower 4, and the other end is branched into a pipe 62 and a pipe 63. The pipe line 62 is connected to the upper part of the first indirect heat exchanger outer cylinder 13. The pressure reducing valve 22 is provided in the pipe line 62. That is, the pressure reducing valve 22 is provided between the high-pressure tower 4 and the first indirect heat exchanger outer cylinder 13.
The pressure reducing valve 22 depressurizes the high-pressure oxygen-enriched liquefied air fluid led out to the pipe line 62. That is, the pressure reducing valve 22 depressurizes a part of the high-pressure oxygen-enriched liquefied air fluid separated by the high-pressure tower 4. The pipe line 62 decompresses a part of the high-pressure oxygen-enriched liquefied air fluid with the pressure-reducing valve 22 to obtain a second low-pressure oxygen-enriched liquefied air fluid, and then introduces it into the first indirect heat exchanger outer cylinder 13.
The pipe 63 is connected to the middle part of the low-pressure tower 5. A part of the pipe line 63 passes through the supercooler 12. The pressure reducing valve 23 is provided between the supercooler 12 and the low pressure column 5 in the pipe line 63. The pressure reducing valve 23 depressurizes the high-pressure oxygen-enriched liquefied air fluid led out to the pipe line 63. The pipe 63 cools the high-pressure oxygen-enriched liquefied air fluid with the supercooler 12, depressurizes it with the pressure reducing valve 23, and then introduces it into the intermediate portion of the low-pressure column 5 as the first low-pressure oxygen-enriched liquefied air fluid. To do. Note that the first low-pressure oxygen-enriched liquefied air fluid introduced into the intermediate portion of the low-pressure column 5 becomes the reflux liquid of the low-pressure column 5.

One end of the pipe line 641 is connected to the middle part of the high-pressure tower 4, and the other end is connected to the fluid passage inlet of the expansion turbine 10. A part of the pipe line 641 passes through the main heat exchanger 11. The pipe line 641 is heated by indirect heat exchange of the high-pressure nitrogen-enriched air fluid in the main heat exchanger 11 and introduced into the expansion turbine 10.
The expansion turbine 10 adiabatically expands the high-pressure nitrogen-enriched air fluid led to the pipe 641 to generate a low-pressure nitrogen-enriched air fluid that is a cold fluid. The expansion turbine 10 generates cold necessary for the air separation device 100 by the adiabatic expansion.
One end of the pipe 642 is connected to the fluid passage outlet of the expansion turbine 10, and the other end is connected to the fluid passage inlet of the first indirect heat exchanger 7. A part of the pipe line 642 passes through the main heat exchanger 11. The pipe line 642 introduces the low-pressure nitrogen-enriched air fluid into the first indirect heat exchanger 7 after cooling it by indirectly exchanging heat with the main heat exchanger 11.

The first indirect heat exchanger outer cylinder 13 is connected to one end of the pipe line 62. The first indirect heat exchanger outer cylinder 13 houses the first indirect heat exchanger 7 therein. The first indirect heat exchanger outer cylinder 13 stores the second low-pressure oxygen-enriched liquefied air fluid introduced from the pipe line 62.
The first indirect heat exchanger 7 is accommodated in the first indirect heat exchanger outer cylinder 13. The fluid passage inlet of the first indirect heat exchanger 7 is connected to one end of the pipe line 642. The first indirect heat exchanger 7 includes a low-pressure nitrogen-enriched air fluid that is a cold fluid, and a second low-pressure oxygen-enriched liquefied air fluid (fluid stored in the first indirect heat exchanger outer cylinder 13). Indirect heat exchange.
More specifically, the first indirect heat exchanger 7 includes a low-pressure nitrogen-enriched air fluid introduced from the line 642 and a second low-pressure oxygen-enriched liquefied air fluid introduced from the line 62. Indirect heat exchange. The first indirect heat exchanger 7 condenses and liquefies the low-pressure nitrogen-enriched air fluid introduced from the pipe 642 by the indirect heat exchange, and is also referred to as a low-pressure nitrogen-enriched liquefied air fluid (“low-pressure liquefied gas fluid”). ) And the second low-pressure oxygen-enriched liquefied air fluid introduced from the pipe 62 is evaporated to generate a low-pressure oxygen-enriched air fluid.

  The pipe 65 has one end connected to the top of the first indirect heat exchanger outer cylinder 13 and the other end connected to the middle of the low-pressure tower 5. Line 65 introduces a low pressure oxygen-enriched air fluid into the middle of low pressure column 5. Note that the low-pressure oxygen-enriched air fluid introduced into the intermediate portion of the low-pressure column 5 becomes the rising gas of the low-pressure column 5.

  One end of the pipe 66 is connected to the bottom of the first indirect heat exchanger outer cylinder 13, and the other end is connected to the middle of the low-pressure column 5. The pressure reducing valve 25 is provided in the pipeline 66. The pressure reducing valve 25 depressurizes the second low-pressure oxygen-enriched liquefied air fluid led out to the pipe line 66. The pipe 66 depressurizes the second low-pressure oxygen-enriched liquefied air fluid pressurized by the liquid head difference by the pressure reducing valve 25, and serves as a second low-pressure oxygen-enriched liquefied air fluid at the intermediate portion of the low-pressure column 5. Introduce. Note that the second low-pressure oxygen-enriched liquefied air fluid introduced into the low-pressure column 5 becomes the reflux liquid of the low-pressure column 5.

  One end of the pipe 67 is connected to the fluid passage outlet of the first indirect heat exchanger 7, and the other end is connected to the upper portion of the low-pressure column 5. A part of the pipe 67 passes through the supercooler 12. The pressure reducing valve 24 is provided between the supercooler 12 and the low pressure column 5 in the pipe line 67. The pressure reducing valve 24 depressurizes the low-pressure nitrogen-enriched liquefied air fluid led out to the pipe line 67. The pipe line 67 introduces the low-pressure nitrogen-enriched liquefied air fluid to the upper portion of the low-pressure column 5 after being cooled by the supercooler 12 and depressurized by the pressure reducing valve 24. The low-pressure nitrogen-enriched liquefied air fluid introduced into the low-pressure column 5 becomes the reflux liquid of the low-pressure column 5.

The low-pressure column 5 is connected to one ends of pipes 59, 63, 65, 66, 67, 68, 69, 70, and 74, respectively.
One end of the pipe line 74 is connected to the top of the second indirect heat exchanger outer cylinder 14, and the other end is connected to the lower part of the low-pressure tower 5. The pipe line 74 introduces the low-pressure oxygen gas fluid generated in the second indirect heat exchanger 8 described later into the low-pressure column 5. Note that the low-pressure oxygen gas fluid introduced into the low-pressure column 5 becomes the rising gas of the low-pressure column 5.

  The low pressure column 5 includes a low pressure liquefied nitrogen fluid introduced from the line 59, a first low pressure oxygen enriched liquefied air fluid introduced from the line 63, and a low pressure oxygen enriched air fluid introduced from the line 65. A second low pressure oxygen enriched liquefied air fluid introduced from line 66, a low pressure nitrogen enriched liquefied air fluid introduced from line 67, and a low pressure oxygen gas fluid introduced from line 74. Cryogenic distillation separates into a low pressure nitrogen gas fluid at the top of the column, a low pressure liquefied oxygen fluid at the bottom of the column, and a low pressure argon enriched liquefied oxygen fluid at the middle. Note that a rectification stage (shelf), a regular filler, an irregular filler, or the like is provided in the low-pressure column 5.

  Specifically, the rising gas (that is, the low-pressure oxygen-enriched air fluid and the low-pressure oxygen gas fluid) of the low-pressure column 5 introduced into the low-pressure column 5 is low-pressure when rising in the low-pressure column 5. Countercurrent contact with the reflux of column 5 (ie, low pressure liquefied nitrogen fluid, first low pressure oxygen enriched liquefied air fluid, second low pressure oxygen enriched liquefied air fluid, and low pressure nitrogen enriched liquefied air fluid) As a result, the composition of low boiling point components increases. On the other hand, the reflux liquid of the low pressure column 5 introduced into the low pressure column 5 (that is, the low pressure liquefied nitrogen fluid, the first low pressure oxygen enriched liquefied air fluid, the second low pressure oxygen enriched liquefied air fluid, and the low pressure nitrogen enriched). Liquefied air fluid) is countercurrently contacted with the ascending gas of the low pressure column 5 (ie, the low pressure oxygen enriched air fluid and the low pressure oxygen gas fluid) when descending in the low pressure column 5; The composition of high-boiling components increases.

A low pressure nitrogen gas fluid is generated at the top of the low pressure column 5. The low pressure nitrogen gas fluid has a nitrogen concentration comprising a low pressure liquefied nitrogen fluid, a first low pressure oxygen enriched liquefied air fluid, a second low pressure oxygen enriched liquefied air fluid, and a low pressure nitrogen enriched liquefied air fluid. 5 is higher than the nitrogen concentration of each fluid of the reflux liquid, and the oxygen concentration of the low-pressure nitrogen gas fluid is lower than the oxygen concentration of each fluid of the reflux liquid of the low-pressure column 5. Low pressure nitrogen gas fluid is led to line 68.
The low pressure liquefied oxygen fluid is generated at the bottom of the low pressure column 5. The nitrogen concentration of the low-pressure liquefied oxygen fluid is lower than the nitrogen concentration of each fluid of the rising gas of the low-pressure column 5 composed of the low-pressure nitrogen-enriched air fluid and the low-pressure oxygen gas fluid, and the oxygen concentration of the low-pressure liquefied oxygen fluid is It is higher than the oxygen concentration of each fluid of the rising gas of 5. The low pressure liquefied oxygen fluid is led to the line 69.
A low pressure argon enriched liquefied oxygen fluid is produced in the middle of the low pressure column 5. The argon concentration of the low pressure argon enriched liquefied oxygen fluid is higher than the argon concentration of the low pressure liquefied oxygen fluid. Low pressure argon enriched liquefied oxygen fluid is directed to line 70.

One end of the pipe 68 is connected to the top of the low-pressure tower 5, and the other end is connected to the third product recovery pipe 43. A part of the pipe 68 passes through the supercooler 12. The low-pressure nitrogen gas fluid led out to the pipe 68 is heated by the supercooler 12.
The third product recovery pipeline 43 is connected to the pipeline 68. A part of the third product recovery conduit 43 passes through the main heat exchanger 11. The third product recovery line 43 is heated by indirect heat exchange of the low-pressure nitrogen gas fluid in the main heat exchanger 11. The third product recovery conduit 43 is a conduit for recovering the low-pressure nitrogen gas fluid led out to the conduit 68 as product low-pressure nitrogen gas.

One end of the pipe 69 is connected to the bottom of the low-pressure tower 5, and the other end is connected to the upper part of the second indirect heat exchanger outer cylinder 14. The liquid pump 31 is provided in the pipe line 69. The liquid pump 31 pressurizes the low-pressure liquefied oxygen fluid led out to the pipe line 69. The pipe 69 introduces the low-pressure liquefied oxygen fluid into the second indirect heat exchanger outer cylinder 14 after pressurizing with the liquid pump 31.
One end of the pipe line 70 is connected to the middle part of the low-pressure column 5, and the other end is connected to the middle part of the argon column 6. The liquid pump 32 is provided in the pipe line 70. The liquid pump 32 pressurizes the low-pressure argon-enriched liquefied oxygen fluid that is led to the line 70. The line 70 introduces the low-pressure argon-enriched liquefied oxygen fluid into the intermediate part of the argon column 6 after pressurizing with the liquid pump 32. The fluid introduced into the intermediate part of the argon tower 6 becomes the reflux liquid of the argon tower 6.

The second indirect heat exchanger outer cylinder 14 is connected to one end of the pipe 69. The second indirect heat exchanger outer cylinder 14 houses the second indirect heat exchanger 8 therein. The second indirect heat exchanger outer cylinder 14 stores the low-pressure liquefied oxygen fluid introduced from the pipe 69.
The second indirect heat exchanger 8 is accommodated in the second indirect heat exchanger outer cylinder 14. The fluid passage inlet of the second indirect heat exchanger 8 is connected to one end of the pipe line 79. The second indirect heat exchanger 8 is introduced from the low-pressure liquefied oxygen fluid (that is, the fluid stored inside the second indirect heat exchanger outer cylinder 14) introduced from the pipe 69 and the pipe 79. Heat exchange with the argon gas fluid. The second indirect heat exchanger 8 condenses and liquefies the argon gas fluid introduced from the pipe 79 by the indirect heat exchange to generate a liquefied argon fluid, and the low pressure liquefied oxygen fluid introduced from the pipe 69. Evaporate to produce a low pressure oxygen gas fluid.

One end of the pipe 71 is connected to the fluid passage outlet of the second indirect heat exchanger 8, and the other end is branched into a pipe 72 and a pipe 73. The pipe line 71 leads a part of the liquefied argon fluid generated by the second indirect heat exchanger 8 to the pipe line 72 and the remaining part to the pipe line 73.
The pipe line 72 is connected to the upper part of the argon tower 6. The pipe 72 introduces a part of the liquefied argon fluid led out to the pipe 71 to the top of the argon tower 6. Note that the liquefied argon fluid introduced to the top of the argon tower 6 becomes the reflux liquid of the argon tower 6.
The conduit 73 is connected to the first product recovery conduit 46. The first product recovery conduit 46 is a conduit for recovering the remainder of the liquefied argon fluid led out to the conduit 71 as product liquefied argon. In the first embodiment, the liquefied argon fluid is recovered as a product, but the argon gas fluid may be recovered as a product.
The pipe line 74 leads the low-pressure oxygen gas fluid generated in the second indirect heat exchanger 8 to the low-pressure column 5. Note that the low-pressure oxygen gas fluid introduced into the low-pressure column 5 becomes the rising gas of the low-pressure column 5.
The pipe 75 has one end connected to the lower part of the second indirect heat exchanger outer cylinder 14 and the other end connected to the lower part of the argon tower 6. The pressure reducing valve 27 is provided in the pipe line 75. The pressure reducing valve 27 depressurizes the low-pressure liquefied oxygen fluid led out to the pipe line 75. The pipe line 75 decompresses the low-pressure liquefied oxygen fluid pressurized by the liquid head difference by the pressure reducing valve 27 and introduces it into the bottom of the argon tower 6.

The argon column 6 is connected to one ends of the pipe lines 70, 72, 75, 76, and 79, respectively.
The argon column 6 is a low-pressure argon-enriched liquefied oxygen fluid introduced from the line 70, a liquefied argon fluid introduced from the line 72, and an intermediate-pressure oxygen gas fluid described later, and is subjected to low-temperature distillation to obtain Separated into an argon gas fluid and a medium pressure liquefied oxygen fluid at the bottom of the column. In the argon column 6, a rectification stage (shelf), a regular filler, an irregular filler, or the like is provided.

Specifically, the low-pressure argon-enriched liquefied oxygen fluid and the liquefied argon fluid introduced into the argon column 6 descend in the argon column 6 as a reflux liquid of the argon column 6. When the reflux liquid of the argon column 6 descends, it comes into countercurrent contact with the ascending gas of the argon column 6 (that is, the medium-pressure oxygen gas fluid), and the low-pressure argon-enriched liquefied oxygen fluid and the liquefied argon fluid The composition of the boiling component increases. On the other hand, the medium-pressure oxygen gas fluid that is the rising gas of the argon tower 6 is the reflux liquid (that is, the low-pressure argon-enriched liquefied oxygen fluid and the liquefied argon fluid) of the argon tower 6 when rising in the argon tower 6. .)), And the composition of the low boiling point component increases.
Argon gas fluid is generated at the top of the argon column 6. The argon gas fluid is led to the line 79. The medium pressure liquefied oxygen fluid is generated at the bottom of the argon column 6. The intermediate pressure liquefied oxygen fluid is led to the conduit 76.

The third indirect heat exchanger 9 is accommodated in the bottom of the argon tower 6. The fluid passage inlet of the third indirect heat exchanger 9 is connected to the pipe line 55. The third indirect heat exchanger 9 indirectly exchanges heat between the high-pressure nitrogen gas fluid introduced from the pipe 55 and the medium-pressure liquefied oxygen fluid stored at the bottom of the argon tower 6. The third indirect heat exchanger 9 condenses and liquefies the high-pressure nitrogen gas fluid introduced from the pipe 55 by the indirect heat exchange to generate a high-pressure liquefied nitrogen fluid and is generated at the bottom of the argon tower 6. The medium pressure liquefied oxygen fluid is evaporated and vaporized to generate the above-described medium pressure oxygen gas fluid.
One end of the pipe 56 is connected to the fluid passage outlet of the third indirect heat exchanger 9. The pipe line 56 leads out the high-pressure liquefied nitrogen fluid generated by the third indirect heat exchanger 9.

One end of the conduit 76 is connected to the bottom of the argon tower 6, and the other end is branched into a conduit 77 and a conduit 78.
The pipe line 77 is connected to the third product recovery pipe line 42. The liquid pump 33 is provided in the pipe line 77. The liquid pump 33 pressurizes a part of the medium-pressure liquefied oxygen fluid led out to the pipe line 76. The pipe line 77 pressurizes a part of the medium pressure liquefied oxygen fluid led out to the pipe line 76 by the liquid pump 33, and introduces the fluid pressurized by the liquid pump 33 into the third product recovery pipe line 42.
The third product recovery pipeline 42 is connected to the pipeline 77. A part of the third product recovery pipeline 42 passes through the main heat exchanger 11. The third product recovery line 42 heats up the remainder of the medium pressure liquefied oxygen fluid led out to the line 76 by the main heat exchanger 11 and raises the temperature.
The third product recovery pipeline 42 is a pipeline that is led to the pipeline 77 and is heated by the main heat exchanger 11 to recover the fluid pressurized by the liquid pump 33 as product high-pressure oxygen gas. The fluid pressurized by the liquid pump 33 is directly supplied from the second indirect heat exchanger outer cylinder 14 to the pipe line 77 via a pipe line (not shown) connected to the second indirect heat exchanger outer cylinder 14. It may be a low pressure liquefied oxygen fluid that is derived.

The pipe line 78 is connected to the second product recovery pipe line 45. The pipe line 78 introduces the remainder of the medium pressure liquefied oxygen fluid led to the pipe line 76 to the second product recovery pipe line 45.
The second product recovery conduit 45 is connected to the conduit 78. The second product recovery conduit 45 is a conduit for recovering the remainder of the medium pressure liquefied oxygen fluid led out to the conduit 76 as product liquefied oxygen gas.
The pipe 79 has one end connected to the upper part of the argon tower 6 and the other end connected to the fluid passage inlet of the second indirect heat exchanger 8. The pipe line 79 introduces an argon gas fluid generated at the top of the argon tower 6 into the second indirect heat exchanger 8.

  The air separation device 100 according to the first embodiment described above has the above-described configuration. According to the air separation device 100 of the first embodiment having such a configuration, the pressure in the first indirect heat exchanger outer cylinder 13 can be set to 130 kPaA. Thus, the first indirect heat exchanger provided above the low-pressure column 5 can be provided without providing a liquid pump in the pipe 62 for feeding a part of the high-pressure oxygen-enriched liquefied air fluid led to the pipe 61. The high-pressure oxygen-enriched liquefied air fluid can be sent to the outer cylinder 13. Therefore, the equipment cost, installation space, and power for installing this liquid pump can be reduced.

Hereinafter, the air separation method of the first embodiment will be described with reference to FIG.
The air separation method of the first embodiment is an air separation method that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools the raw material air to obtain a high-pressure raw material air fluid; and A high-pressure separation step of separating the high-pressure feed air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation; and a part of the high-pressure feed air fluid or the high-pressure nitrogen An adiabatic expansion step of adiabatic expansion of any of the enriched air fluids to generate a cold fluid; the cold fluid; and a low pressure oxygen enriched liquefied air fluid obtained by decompressing the high pressure oxygen enriched liquefied air fluid; , Indirect heat exchange, condensing and liquefying the cold fluid to obtain a low-pressure liquefied gas fluid, and evaporating and vaporizing the low-pressure oxygen-enriched liquefied air fluid to obtain a low-pressure oxygen-enriched air fluid. And said A low-pressure separation step for separating a pressurized oxygen-enriched air fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through an expansion turbine; and the low-pressure argon-enriched liquefied oxygen After pressurizing the fluid, an argon separation step of separating the argon gas fluid and the medium-pressure liquefied oxygen fluid by low-temperature distillation; indirectly exchanging heat between the argon gas fluid and the low-pressure liquefied oxygen fluid; A second indirect heat exchange step of condensing and liquefying to obtain a liquefied argon fluid and evaporating and evaporating the low-pressure liquefied oxygen fluid to obtain a low-pressure oxygen gas fluid; and indirectly coupling the high-pressure nitrogen gas fluid and the medium-pressure liquefied oxygen fluid Heat exchange is performed to condense and liquefy the high-pressure nitrogen gas fluid to obtain a high-pressure liquefied nitrogen fluid, and to evaporate and vaporize the intermediate-pressure liquefied oxygen fluid. A third indirect heat exchange step to be obtained, and a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid that has not been liquefied in the second indirect heat exchange step. A first product recovery step derived as product argon gas, a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid or a part of the high-pressure liquefied nitrogen fluid. A second product recovery step of deriving at least one or more fluids as products.

Raw material air is introduced into the pipe 50. The raw material air introduced into the pipe 50 is compressed by the first raw material air compressor 1, and impurities such as water and carbon dioxide contained in the raw material air are removed by the purifier 2.
Part of the raw material air from which impurities have been removed by the purifier 2 is cooled by the main heat exchanger 11 via the pipe 51 and becomes the first high-pressure raw material air fluid (raw material air compression step).

  The remainder of the raw material air from which impurities have been removed by the purifier 2 is further compressed and pressurized by the second raw material air compressor 3 provided in the pipe 52 branched from the pipe 51, and then the main heat exchanger 11 is cooled. The raw material air cooled by the main heat exchanger 11 is depressurized by the pressure reducing valve 21 and becomes a second high-pressure raw material air fluid (raw material air compression step). As described above, in the raw air compression step, the raw air is compressed, purified, and cooled to obtain the first and second high-pressure raw air fluids.

  In the main heat exchanger 11, indirect connection between the high-temperature fluid flowing through the pipe lines 51, 52, and 642 and the low-temperature fluid flowing through the pipe line 641, the second product recovery pipe line 41, and the third product recovery pipe lines 42 and 43. The heat exchange cools the high temperature fluid and raises the temperature of the low temperature fluid.

  In the high-pressure separation step, the first and second high-pressure raw air fluids are separated into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation. Specifically, in the high-pressure tower 4, the first and second high-pressure raw air fluids introduced via the pipelines 51 and 52 and the high-pressure liquefied nitrogen fluid introduced via the pipeline 57 are subjected to low-temperature distillation. Is separated into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid (high-pressure separation step). A high-pressure nitrogen gas fluid is generated at the top of the high-pressure column 4, a high-pressure nitrogen-enriched air fluid is generated at the middle of the high-pressure column 4, and a high-pressure oxygen-enriched liquefied air fluid is generated at the bottom of the high-pressure column 4. Generated.

The high-pressure oxygen-enriched liquefied air fluid at the bottom of the high-pressure tower 4 is led to the pipe 61. A part of the high-pressure oxygen-enriched liquefied air fluid led out to the pipe line 61 is depressurized to a predetermined pressure by the pressure reducing valve 22 via the pipe line 62, and is then used as a second low-pressure oxygen-enriched liquefied air fluid. It is introduced into the first indirect heat exchanger outer cylinder 13.
The remaining portion of the high-pressure oxygen-enriched liquefied air fluid led to the pipe 61 is cooled by the supercooler 12 through the pipe 63 and reduced to a predetermined pressure by the pressure reducing valve 23, and then the first low-pressure The oxygen-enriched liquefied air fluid is introduced into the low-pressure column 5 and becomes the reflux liquid of the low-pressure column 5.

  The high-pressure nitrogen-enriched air fluid in the intermediate portion of the high-pressure tower 4 is introduced into the expansion turbine 10 after being heated by indirect heat exchange in the main heat exchanger 11 via the pipe line 641. A part of the high-pressure nitrogen-enriched air fluid is adiabatically expanded by the expansion turbine 10 to generate a low-pressure nitrogen-enriched air fluid that is a cold fluid (adiabatic expansion step). That is, in the adiabatic expansion step, the high-pressure nitrogen-enriched air fluid is adiabatically expanded to generate a cold fluid. Due to the adiabatic expansion, the cooling required for the air separation device 100 is generated. After the necessary cooling in the air separation device 100 occurs, the low-pressure nitrogen-enriched air fluid is cooled by indirect heat exchange in the main heat exchanger 11 via the line 642 and introduced into the first indirect heat exchanger 7. Is done.

  The high-pressure nitrogen gas fluid at the top of the high-pressure column 4 is led to the pipe 53. A part of the high-pressure nitrogen gas fluid led out to the pipe line 53 is led out to the second product recovery pipe line 41 via the pipe line 54, and is heated by indirect heat exchange in the main heat exchanger 11, and the second The product is extracted as product high-pressure nitrogen gas from the product recovery line 41 (second product recovery step).

  The remainder of the high-pressure nitrogen gas fluid led out to the pipe line 53 is introduced into the third indirect heat exchanger 9 through the pipe line 55. The high-pressure nitrogen gas fluid introduced into the third indirect heat exchanger 9 via the pipe 55 is condensed and liquefied by indirect heat exchange with the medium-pressure liquefied oxygen fluid at the bottom of the argon column 6. While becoming a nitrogen fluid, the medium pressure liquefied oxygen fluid at the bottom of the argon column 6 is evaporated and vaporized to generate a medium pressure oxygen gas fluid (third indirect heat exchange step).

A part of the high-pressure liquefied nitrogen fluid led out from the third indirect heat exchanger 9 to the pipe 56 is introduced into the high-pressure tower 4 via the pipe 57 and becomes a reflux liquid of the high-pressure tower 4.
The remainder of the high-pressure liquefied nitrogen fluid led out from the third indirect heat exchanger 9 to the pipe 56 is cooled by the supercooler 12 via the pipe 58.
A part of the high-pressure liquefied nitrogen fluid cooled by the subcooler 12 is reduced to a predetermined pressure by the pressure reducing valve 26 via the pipe 59 and then introduced into the low-pressure column 5 as a low-pressure liquefied nitrogen fluid. It becomes the reflux liquid of the low pressure column 5.
The remainder of the high-pressure liquefied nitrogen fluid cooled by the supercooler 12 is led out as product liquefied nitrogen from the second product recovery pipe 44 via the pipe 60 (second product recovery step).

The low-pressure nitrogen-enriched air fluid introduced into the first indirect heat exchanger 7 via the pipe line 642 is a cold fluid generated by adiabatically expanding a part of the high-pressure nitrogen-enriched air fluid. The second low-pressure oxygen-enriched liquefied air fluid inside the first indirect heat exchanger outer cylinder 13 is a fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid.
The indirect heat exchange between the low-pressure nitrogen-enriched air fluid that is a cold fluid and the second low-pressure oxygen-enriched liquefied air fluid causes the low-pressure nitrogen-enriched air fluid that is a cold fluid to condense and liquefy itself. It becomes a nitrogen-enriched liquefied air fluid (that is, a low-pressure liquefied gas fluid), and the second low-pressure oxygen-enriched liquefied air fluid is evaporated to produce a low-pressure oxygen-enriched air fluid (first indirect heat). Exchange process).

The second low-pressure oxygen-enriched liquefied air fluid is depressurized to a predetermined pressure by the pressure reducing valve 25 after being pressurized from the bottom of the first indirect heat exchanger outer cylinder 13 through the pipe 66 by the liquid head difference. After that, the second low-pressure oxygen-enriched liquefied air fluid is introduced into the low-pressure column 5 and becomes the reflux liquid of the low-pressure column 5.
The low-pressure nitrogen-enriched liquefied air fluid is cooled by the supercooler 12 through the pipe 67 from the first indirect heat exchanger 7, and is reduced to a predetermined pressure by the pressure reducing valve 24, and then introduced into the low-pressure column 5. And becomes the reflux liquid of the low-pressure column 5.

  In the low-pressure column 5, the low-pressure liquefied nitrogen fluid introduced via the line 59, the first low-pressure oxygen-enriched liquefied air fluid introduced via the line 63, and the line 66 are introduced. Second low pressure oxygen enriched liquefied air fluid, low pressure nitrogen enriched liquefied air fluid introduced via line 67, low pressure oxygen enriched air fluid introduced via line 65, and line 74 The low-pressure oxygen gas fluid introduced via the low-pressure column is subjected to low-temperature distillation, the low-pressure nitrogen gas fluid at the top of the low-pressure column 5, the low-pressure liquefied oxygen fluid at the bottom of the low-pressure column 5, and the low-pressure in the middle of the low-pressure column 5 Separated into argon-enriched liquefied oxygen fluid (low pressure separation step). In the low-pressure separation process of the embodiment, the low-pressure oxygen-enriched air fluid is used for low-temperature distillation without going through the expansion turbine. The low pressure oxygen gas fluid constitutes the rising gas of the low pressure column 5.

The low-pressure nitrogen gas fluid at the top of the low-pressure column 5 is heated by the supercooler 12 via the line 68 and further heated by indirect heat exchange in the main heat exchanger 11, and the third product recovery line 43 is derived as product low-pressure nitrogen gas.
The low-pressure argon-enriched liquefied oxygen fluid in the intermediate portion of the low-pressure column 5 is pressurized to a predetermined pressure by the liquid pump 32 via the conduit 70 and then introduced into the intermediate portion of the argon column 6. The reflux liquid becomes.
The low-pressure liquefied oxygen fluid at the bottom of the low-pressure tower 5 is pressurized to a predetermined pressure by the liquid pump 31 via the pipe 69 and then introduced into the second indirect heat exchanger outer cylinder 14.

  The high-pressure nitrogen gas fluid at the top of the high-pressure column 4 is introduced into the third indirect heat exchanger 9 accommodated at the bottom of the argon column 6 via the pipe line 53.

The argon gas fluid introduced into the second indirect heat exchanger 8 via the pipe line 79 is condensed and liquefied by indirect heat exchange with the low-pressure liquefied oxygen fluid inside the second indirect heat exchanger outer cylinder 14. Then, the low-pressure liquefied oxygen fluid is evaporated and vaporized to generate a low-pressure oxygen gas fluid (second indirect heat exchange step).
The liquefied argon fluid is led to line 71. A part of the liquefied argon fluid led out to the pipe 71 is introduced into the top of the argon tower 6 through the pipe 72 and becomes a reflux liquid of the argon tower 6.
The low pressure oxygen gas fluid is led to the line 74. The low-pressure oxygen gas fluid led out to the pipe line 74 is introduced into the lower part of the low-pressure column 5 and constitutes the rising gas of the low-pressure column 5.
A part of the low-pressure liquefied oxygen fluid at the bottom of the second indirect heat exchanger outer cylinder 14 is led to the pipe 75. The low-pressure liquefied oxygen fluid led out to the pipe line 75 is pressurized by the liquid head difference, is decompressed to a predetermined pressure by the decompression valve 27, and is then introduced into the argon tower 6.

  The remainder of the liquefied argon fluid led out to the pipeline 71 is led out as product liquefied argon from the first product recovery pipeline 46 via the pipeline 73 (first product recovery step). In the first embodiment, the liquefied argon fluid is recovered as a product, but the argon gas fluid may be recovered as a product.

In the argon column 6, the low-pressure argon-enriched liquefied oxygen fluid introduced via the line 70, a part of the liquefied argon fluid introduced via the line 72, and the medium-pressure oxygen gas fluid are subjected to low-temperature distillation. The argon gas fluid at the top of the argon column 6 and the medium pressure liquefied oxygen fluid at the bottom of the argon column 6 are separated (argon separation step).
The argon gas fluid at the top of the argon column 6 is introduced into the second indirect heat exchanger 8 via a pipe line 79.

The medium-pressure liquefied oxygen fluid at the bottom of the argon column 6 is led to the conduit 76. A part of the medium-pressure liquefied oxygen fluid led out to the pipe line 76 is pressurized to a predetermined pressure by the liquid pump 33 via the pipe line 77 and then evaporated and evaporated by indirect heat exchange in the main heat exchanger 11. And the temperature is raised, and the product is extracted from the third product recovery line 42 as product high-pressure oxygen gas (second product recovery step). Note that the low-pressure liquefied oxygen fluid stored in the second indirect heat exchanger outer cylinder 14 may be used as the fluid supplied to the liquid pump 33.
The remainder of the medium-pressure liquefied oxygen fluid led out to the conduit 76 is led out as product liquefied oxygen from the second product recovery conduit 45 via the conduit 78.

  In the air separation method and apparatus of the first embodiment, the pressure in the indirect heat exchanger outer cylinder 13 is 130 kPaA. Thereby, it is not necessary to provide a liquid pump in the pipe line 62 for feeding a part of the high-pressure oxygen-enriched liquefied air fluid, and the equipment cost, installation space, and power for installing the liquid pump can be reduced.

[Second Embodiment]
An air separation device according to a second embodiment is an air separation device that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools raw material air to obtain a high-pressure raw material air fluid, The high pressure raw material air fluid is subjected to low temperature distillation to rectify and separate the high pressure nitrogen gas fluid at the top of the tower, the high pressure nitrogen enriched air fluid at the middle, and the high pressure oxygen enriched liquefied air fluid at the bottom of the tower; An expansion turbine that adiabatically expands a portion of the high-pressure nitrogen gas fluid to generate a cold fluid, the cold fluid, and a low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid, First indirect heat exchange in which the cryogenic fluid is condensed and liquefied to generate a low pressure liquefied gas fluid, and the low pressure oxygen enriched liquefied air fluid is evaporated to generate a low pressure oxygen enriched air fluid. And the low-pressure oxygen enrichment A low-pressure column for separating a gas fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through the expansion turbine; and pressurizing the low-pressure argon-enriched liquefied oxygen fluid After that, an argon tower that is separated into an argon gas fluid and a medium-pressure liquefied oxygen fluid by low-temperature distillation, and the argon gas fluid and the low-pressure liquefied oxygen fluid are indirectly heat-exchanged to condense and liquefy the argon gas fluid. A second indirect heat exchanger that generates an argon fluid and evaporates and vaporizes the low-pressure liquefied oxygen fluid to generate a low-pressure oxygen gas fluid; and indirectly heat-exchanges the high-pressure nitrogen gas fluid and the intermediate-pressure liquefied oxygen fluid. The high-pressure nitrogen gas fluid is condensed and liquefied to generate a high-pressure liquefied nitrogen fluid, and the intermediate-pressure liquefied oxygen fluid is evaporated to generate a medium-pressure oxygen gas fluid 3. Indirect heat exchanger, and part of the argon gas fluid, part of the liquefied argon fluid or argon gas fluid not liquefied in the second indirect heat exchanger A first product recovery line that is led out as a gas, a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid And a second product recovery line for deriving at least one fluid as a product.

FIG. 2 is a system diagram showing a schematic configuration of an air separation device 200 according to the second embodiment of the present invention. 2, the same components as those of the air separation device 100 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
In the description of the second embodiment, “low pressure” refers to a pressure that is equal to or higher than the pressure of the product low-pressure nitrogen gas and lower than the operating pressure of the argon tower 6. “Medium pressure” refers to a pressure that is equal to or higher than the operating pressure of the argon tower 6 and lower than the pressure of the product high-pressure nitrogen gas. “High pressure” means a pressure higher than the pressure of the product high-pressure nitrogen gas.

  As shown in FIG. 2, the air separation device 200 according to the second embodiment includes the pipes 641 constituting the air separation device 100 according to the first embodiment removed from the components, and the pipes 80, 81, 82. , And the air separation device 100 except that the pressure reducing valve 28 is provided.

One end of the pipe 80 is connected to the fluid passage inlet of the expansion turbine 10, and the other end is connected to a portion of the second product recovery pipe 41 that passes through the main heat exchanger 11. That is, one end of the second product recovery conduit 41 is connected to the conduit 54, and the other end is branched into a conduit 80 and a conduit 81. The pipe 81 is the same as the portion of the second product recovery pipe 41 on the secondary side from the position where the pipe 80 and the second product recovery pipe 41 are connected.
The pipe 80 introduces a part of the high-pressure nitrogen gas fluid led out to the second product recovery pipe 41 and heated by the main heat exchanger 11 to the expansion turbine 10.
The pipe 81 is a pipe for recovering the remainder of the high-pressure nitrogen gas fluid led out to the second product recovery pipe 41 and heated by the main heat exchanger 11 as product high-pressure nitrogen gas.
One end of the pipe line 82 is connected to the middle part of the high-pressure column 4, and the other end is connected to the middle part of the low-pressure column 5. A part of the pipe line 82 passes through the supercooler 12. The pressure reducing valve 28 is provided between the supercooler 12 and the low pressure column 5 in the pipe line 82. The pressure reducing valve 28 depressurizes the reflux liquid of the high pressure column 4 led out to the pipe line 82. In the pipe line 82, a part of the reflux liquid of the high-pressure column 4 is cooled by the supercooler 12, depressurized by the pressure reducing valve 28, and then introduced into the intermediate portion of the low-pressure column 5.

  In the air separation device 200 of the second embodiment configured as described above, the expansion turbine 10 adiabatically expands a part of the high-pressure nitrogen gas fluid, and thus the air separation device 100 of the first embodiment described above and The same effect is produced.

Hereinafter, the air separation method of the second embodiment will be described with reference to FIG.
The air separation method of the second embodiment is an air separation method for separating raw material air by a cryogenic separation method, and compresses, purifies, and cools raw material air to obtain a high-pressure raw material air fluid; and A high-pressure separation step of separating the high-pressure raw material air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation; and a part of the high-pressure nitrogen gas fluid is adiabatically expanded. Adiabatic expansion step for generating a cryogenic fluid; indirect heat exchange between the cryogenic fluid and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid to condense the cryogenic fluid A first indirect heat exchange step for obtaining a low-pressure oxygen-enriched air fluid by evaporating and evaporating the low-pressure oxygen-enriched liquefied air fluid, and obtaining a low-pressure oxygen-enriched air fluid; Via A low-pressure separation step for separating the low-pressure nitrogen gas fluid, the low-pressure liquefied oxygen fluid, and the low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation, and pressurizing the low-pressure argon-enriched liquefied oxygen fluid, An argon separation step of separating the fluid into an intermediate pressure liquefied oxygen fluid, indirect heat exchange between the argon gas fluid and the low pressure liquefied oxygen fluid, condensing and liquefying the argon gas fluid to obtain a liquefied argon fluid, A second indirect heat exchange step of evaporating and evaporating the low pressure liquefied oxygen fluid to obtain a low pressure oxygen gas fluid, indirect heat exchange between the high pressure nitrogen gas fluid and the intermediate pressure liquefied oxygen fluid, and condensing and liquefying the high pressure nitrogen gas fluid To obtain a high-pressure liquefied nitrogen fluid and evaporate and vaporize the medium-pressure liquefied oxygen fluid to obtain a medium-pressure oxygen gas fluid; and the argon gas A first product recovery step of deriving at least one argon fluid as a product argon gas out of a part of the fluid, a part of the liquefied argon fluid, or an argon gas fluid not liquefied in the second indirect heat exchange step; A part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid or a part of the high-pressure liquefied nitrogen fluid as a product. And a second product recovery step.

  In the air separation method of the second embodiment, a part of the high-pressure nitrogen gas fluid at the top of the high-pressure column 4 is transferred to the line 80 via the line 53, the line 54, and the second product recovery line 41. The first embodiment described above is derived except that the air cooling apparatus 200 generates the necessary cooling by introducing the high-pressure nitrogen gas fluid from the pipe 80 to the expansion turbine 10. It can be performed by a method similar to the air separation method.

In the air separation method of the second embodiment, a part of the high-pressure nitrogen gas fluid at the top of the high-pressure tower 4 led to the pipe 53 is led to the second product recovery pipe 41 via the pipe 54. The The high-pressure nitrogen gas fluid led to the second product recovery pipe 41 is heated by the main heat exchanger 11.
A part of the high-pressure nitrogen gas fluid led out to the second product recovery pipe 41 and heated by the main heat exchanger 11 is adiabatically expanded by the expansion turbine 10 to generate the necessary cold in the air separation device 200.
The cold fluid generated by adiabatic expansion by the expansion turbine 10 is cooled by the main heat exchanger 11 via the pipe line 642 and then introduced into the first indirect heat exchanger 7.

  In the air separation method of the second embodiment, the reflux liquid descending the high pressure column 4 led out to the pipe 82 is cooled by the supercooler 12, depressurized by the pressure reducing valve 28, and then the middle of the low pressure column 5. Introduced into the department. The low-pressure nitrogen-enriched liquefied air fluid introduced into the intermediate portion of the low-pressure column 5 after being depressurized by the pressure reducing valve 28 becomes the reflux liquid of the low-pressure column 5.

  In the air separation method of the second embodiment using the air separation device 200 shown in FIG. 2, a part of the high-pressure nitrogen gas fluid is adiabatically expanded, so that it is the same as the air separation method of the first embodiment described above. The effect of.

[Third Embodiment]
An air separation device according to a third embodiment is an air separation device that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools the raw material air to obtain a high-pressure raw material air fluid, The high pressure raw material air fluid is subjected to low temperature distillation to rectify and separate the high pressure nitrogen gas fluid at the top of the tower, the high pressure nitrogen enriched air fluid at the middle, and the high pressure oxygen enriched liquefied air fluid at the bottom of the tower; An expansion turbine that adiabatically expands a part of the high-pressure raw material air fluid to generate a cold fluid, the cold fluid, and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid, First indirect heat exchange in which the cryogenic fluid is condensed and liquefied to generate a low pressure liquefied gas fluid, and the low pressure oxygen enriched liquefied air fluid is evaporated to generate a low pressure oxygen enriched air fluid. And the low-pressure oxygen enrichment A low-pressure column for separating a gas fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through the expansion turbine; and pressurizing the low-pressure argon-enriched liquefied oxygen fluid After that, an argon tower that is separated into an argon gas fluid and a medium-pressure liquefied oxygen fluid by low-temperature distillation, and the argon gas fluid and the low-pressure liquefied oxygen fluid are indirectly heat-exchanged to condense and liquefy the argon gas fluid. A second indirect heat exchanger that generates an argon fluid and evaporates and vaporizes the low-pressure liquefied oxygen fluid to generate a low-pressure oxygen gas fluid; and indirectly heat-exchanges the high-pressure nitrogen gas fluid and the intermediate-pressure liquefied oxygen fluid. The high-pressure nitrogen gas fluid is condensed and liquefied to generate a high-pressure liquefied nitrogen fluid, and the intermediate-pressure liquefied oxygen fluid is evaporated to generate a medium-pressure oxygen gas fluid 3. Indirect heat exchanger, and part of the argon gas fluid, part of the liquefied argon fluid or argon gas fluid not liquefied in the second indirect heat exchanger A first product recovery line that is led out as a gas, a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid And a second product recovery line for deriving at least one fluid as a product.

FIG. 3 is a system diagram showing a schematic configuration of an air separation device according to a third embodiment of the present invention. In FIG. 3, the same components as those of the air separation device 100 of the first embodiment shown in FIG.
In the description of the third embodiment, “low pressure” refers to a pressure that is equal to or higher than the pressure of the product low-pressure nitrogen gas and lower than the operating pressure of the argon tower 6. “Medium pressure” refers to a pressure that is equal to or higher than the operating pressure of the argon tower 6 and lower than the pressure of the product high-pressure nitrogen gas. “High pressure” means a pressure higher than the pressure of the product high-pressure nitrogen gas.

  As shown in FIG. 3, the air separation device 300 of the third embodiment includes a second raw material air compressor 3, a pressure reducing valve 21, a pipe line 52, and a pipe that constitute the air separation device 100 of the first embodiment. The configuration is the same as that of the air separation device 100 except that the path 641 is excluded from the components, and the pipes 83 and 84, the pressure reducing valve 29, and the compressor 35 are included.

One end of the pipe 83 is connected to the fluid passage inlet of the expansion turbine 10, and the other end is connected to a part of the pipe 51 that passes through the main heat exchanger 11.
The pipe 83 introduces a part of the high-pressure raw material air fluid compressed by the first raw material air compressor 1 and impurities removed by the purifier 2 to the expansion turbine 10.
One end of the pipe 84 is connected to the upper part of the high-pressure tower 4, and the other end is connected to a part of the second product recovery pipe 41 that does not pass through the main heat exchanger 11. That is, one end of the second product recovery pipeline 41 is connected to the pipeline 54 and the other end is branched into a pipeline 84 and a pipeline 85. The pipe 85 is the same as the portion of the second product recovery pipe 41 on the secondary side from the position where the pipe 84 and the second product recovery pipe 41 are connected.
The compressor 35 is provided between the main heat exchanger 11 and a position branching from the second product recovery pipe 41 in the pipe 84. The compressor 35 compresses a part of the high-pressure nitrogen gas fluid led out to the second product recovery pipeline 41 to generate a pressurized nitrogen gas fluid.
The pressure reducing valve 29 is provided between the main heat exchanger 11 and the high-pressure tower 4 in the pipe line 84. The pressure reducing valve 29 depressurizes the pressurized nitrogen gas fluid heated by the main heat exchanger 11 and compressed by the compressor 35.
The pipe 84 compresses a part of the high-pressure nitrogen gas fluid led out to the second product recovery pipe 41 with the compressor 35 to form a pressurized nitrogen gas fluid, and the pressurized nitrogen gas fluid is cooled by the main heat exchanger 11. The pressure is reduced by the pressure reducing valve 29 and then introduced into the top of the high pressure column 4.

  In the air separation device 300 of the third embodiment configured as described above, the expansion turbine 10 adiabatically expands a part of the high-pressure raw material air fluid, and thus the air separation device 100 of the first embodiment described above and The same effect is produced.

Hereinafter, the air separation method of the third embodiment will be described with reference to FIG.
The air separation method of the third embodiment is an air separation method that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools the raw material air to obtain a high-pressure raw material air fluid; and A high-pressure separation step of separating the high-pressure raw material air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation; and a part of the high-pressure raw material air fluid is adiabatically expanded. Adiabatic expansion step for generating a cryogenic fluid; indirect heat exchange between the cryogenic fluid and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid to condense the cryogenic fluid A first indirect heat exchange step for obtaining a low-pressure oxygen-enriched air fluid by evaporating and evaporating the low-pressure oxygen-enriched liquefied air fluid, and obtaining a low-pressure oxygen-enriched air fluid; Via A low-pressure separation step for separating the low-pressure nitrogen gas fluid, the low-pressure liquefied oxygen fluid, and the low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation, and pressurizing the low-pressure argon-enriched liquefied oxygen fluid, An argon separation step of separating the fluid into an intermediate pressure liquefied oxygen fluid, indirect heat exchange between the argon gas fluid and the low pressure liquefied oxygen fluid, condensing and liquefying the argon gas fluid to obtain a liquefied argon fluid, A second indirect heat exchange step of evaporating and evaporating the low pressure liquefied oxygen fluid to obtain a low pressure oxygen gas fluid, indirect heat exchange between the high pressure nitrogen gas fluid and the intermediate pressure liquefied oxygen fluid, and condensing and liquefying the high pressure nitrogen gas fluid To obtain a high-pressure liquefied nitrogen fluid and evaporate and vaporize the medium-pressure liquefied oxygen fluid to obtain a medium-pressure oxygen gas fluid; and the argon gas A first product recovery step of deriving at least one argon fluid as a product argon gas out of a part of the fluid, a part of the liquefied argon fluid, or an argon gas fluid not liquefied in the second indirect heat exchange step; A part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid or a part of the high-pressure liquefied nitrogen fluid as a product. And a second product recovery step.

  In the air separation method of the third embodiment, a part of the high pressure raw material air fluid compressed by the first raw material air compressor 1 and impurities removed by the purifier 2 is passed through the pipe 83 to the expansion turbine 10. Is introduced into the air separation device 300 to generate necessary cooling, and compresses a part of the high-pressure nitrogen gas fluid led to the pipe line 84 through the second product recovery pipe line 41. Except for compressing by the machine 35 and generating the pressurized nitrogen gas fluid, the same method as the air separation method of the first embodiment described above can be used.

In the air separation method of the third embodiment, a part of the high-pressure raw material air fluid compressed by the first raw material air compressor 1 and impurities removed by the purifier 2 is led to the pipe 83. A part of the high-pressure raw material air fluid led out to the pipe 83 is adiabatically expanded by the expansion turbine 10 to generate cold necessary for the air separation device 300.
The cold fluid generated by adiabatic expansion in the expansion turbine 10 is cooled by the main heat exchanger 11 via the pipe 642 and then introduced into the first indirect heat exchanger 7.

  In the air separation method of the third embodiment, the high-pressure nitrogen gas fluid led out to the pipe 84 is boosted to a predetermined pressure by the compressor 35 and becomes a boosted nitrogen gas fluid. The pressurized nitrogen gas fluid is cooled by the main heat exchanger 11, depressurized to a predetermined pressure by the pressure reducing valve 29, and then introduced into the top of the high pressure column 4.

  Since the air separation method of the third embodiment using the air separation device 300 shown in FIG. 3 adiabatically expands a part of the high-pressure raw material air fluid, it is the same as the air separation method of the first embodiment described above. The effect of.

[Fourth Embodiment]
The air separation device according to the fourth embodiment is an air separation device that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools the raw material air to obtain a high-pressure raw material air fluid, , High-pressure column for rectifying and separating a part of the high-pressure nitrogen gas fluid into a high-pressure nitrogen gas fluid at the top of the column, a high-pressure nitrogen-enriched air fluid at the middle, and a high-pressure oxygen-enriched liquefied air fluid at the bottom of the column An expansion turbine that adiabatically expands a part of the high-pressure nitrogen gas fluid to generate a cold fluid, and the low-pressure oxygen-enriched liquefied air obtained by decompressing the cold fluid and the high-pressure oxygen-enriched liquefied air fluid A fluid is indirectly exchanged with heat to condense and liquefy the cold fluid to produce a low pressure liquefied gas fluid, and evaporate and vaporize the low pressure oxygen enriched liquefied air fluid to produce a low pressure oxygen enriched air fluid. An indirect heat exchanger and the low-pressure acid A low-pressure column that separates the enriched air fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through the expansion turbine; and the low-pressure argon-enriched liquefied oxygen fluid After the pressurization, the argon gas fluid is separated into an argon gas fluid and an intermediate pressure liquefied oxygen fluid by low-temperature distillation, and the argon gas fluid and the low pressure liquefied oxygen fluid are indirectly heat exchanged to condense and liquefy the argon gas fluid. Generating a liquefied argon fluid and evaporating and evaporating the low-pressure liquefied oxygen fluid to generate a low-pressure oxygen gas fluid; and indirectly heating the high-pressure nitrogen gas fluid and the intermediate-pressure liquefied oxygen fluid. The high-pressure nitrogen gas fluid is condensed and liquefied to generate a high-pressure liquefied nitrogen fluid, and the intermediate-pressure liquefied oxygen fluid is evaporated and vaporized to generate a medium-pressure oxygen gas fluid. A third indirect heat exchanger, a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid not liquefied by the second indirect heat exchanger, at least one kind of argon fluid A first product recovery line leading out as product argon gas, a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid or a part of the high-pressure liquefied nitrogen fluid And a second product recovery conduit for deriving at least one kind of fluid as a product.

  FIG. 4 is a system diagram showing a schematic configuration of an air separation device according to a fourth embodiment of the present invention. 4, the same components as those of the air separation devices 100, 200, and 300 of the first to third embodiments shown in FIGS. 1 to 3 are denoted by the same reference numerals, and the description thereof is omitted.

  In the description of the fourth embodiment, “low pressure” refers to a pressure that is equal to or higher than the pressure of the product low-pressure nitrogen gas and lower than the operating pressure of the argon tower 6. “Medium pressure” refers to a pressure that is equal to or higher than the operating pressure of the argon tower 6 and lower than the pressure of the product high-pressure nitrogen gas. “High pressure” means a pressure higher than the pressure of the product high-pressure nitrogen gas.

  As shown in FIG. 4, the air separation device 400 of the fourth embodiment includes a second raw material air compressor 3, a pressure reducing valve 21, a pipe line 52, and a pipe that constitute the air separation device 100 of the first embodiment. The configuration is the same as that of the air separation device 100 except that the passage 641 is excluded from the constituent elements and the pipes 80 and 84, the pressure reducing valve 29, and the compressor 35 are provided.

  In the air separation device 400 of the fourth embodiment configured as described above, the expansion turbine 10 adiabatically expands part of the high-pressure nitrogen gas fluid, and thus the air separation device 100 of the first embodiment described above and The same effect is produced.

Hereinafter, the air separation method of the fourth embodiment will be described with reference to FIG.
The air separation method of the fourth embodiment is an air separation method for separating raw material air by a cryogenic separation method, and compresses, purifies, and cools the raw material air to obtain a high-pressure raw material air fluid; and A high-pressure separation step of separating the high-pressure raw material air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation; and a part of the high-pressure nitrogen gas fluid is adiabatically expanded. Adiabatic expansion step for generating a cryogenic fluid; indirect heat exchange between the cryogenic fluid and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid to condense the cryogenic fluid A first indirect heat exchange step for obtaining a low-pressure oxygen-enriched air fluid by evaporating and evaporating the low-pressure oxygen-enriched liquefied air fluid, and obtaining a low-pressure oxygen-enriched air fluid; Via A low-pressure separation step for separating the low-pressure nitrogen gas fluid, the low-pressure liquefied oxygen fluid, and the low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation, and pressurizing the low-pressure argon-enriched liquefied oxygen fluid, An argon separation step of separating the fluid into an intermediate pressure liquefied oxygen fluid, indirect heat exchange between the argon gas fluid and the low pressure liquefied oxygen fluid, condensing and liquefying the argon gas fluid to obtain a liquefied argon fluid, A second indirect heat exchange step of evaporating and evaporating the low pressure liquefied oxygen fluid to obtain a low pressure oxygen gas fluid, indirect heat exchange between the high pressure nitrogen gas fluid and the intermediate pressure liquefied oxygen fluid, and condensing and liquefying the high pressure nitrogen gas fluid To obtain a high-pressure liquefied nitrogen fluid and evaporate and vaporize the medium-pressure liquefied oxygen fluid to obtain a medium-pressure oxygen gas fluid; and the argon gas A first product recovery step of deriving at least one argon fluid as a product argon gas out of a part of the fluid, a part of the liquefied argon fluid, or an argon gas fluid not liquefied in the second indirect heat exchange step; A part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid or a part of the high-pressure liquefied nitrogen fluid as a product. And a second product recovery step.

  In the air separation method of the fourth embodiment, a part of the high-pressure nitrogen gas fluid at the top of the high-pressure column 4 is transferred to the line 80 via the line 53, the line 54, and the second product recovery line 41. Deriving and introducing the high-pressure nitrogen gas fluid from the line 80 to the expansion turbine 10 to generate the cold necessary for the air separation device 400, and via the second product recovery line 41, The air separation method of the first embodiment described above, except that a part of the high-pressure nitrogen gas fluid led out to the pipe 84 is compressed by the compressor 35 to generate the pressure-increased nitrogen gas fluid. A similar method can be used.

In the air separation method of the fourth embodiment, a part of the high-pressure nitrogen gas fluid at the top of the high-pressure tower 4 led to the pipe 53 is led to the second product recovery pipe 41 via the pipe 54. The The high-pressure nitrogen gas fluid led to the second product recovery pipe 41 is heated by the main heat exchanger 11.
A part of the high-pressure nitrogen gas fluid led out to the second product recovery pipe 41 and heated in the main heat exchanger 11 is led out to the pipe 80, adiabatically expanded by the expansion turbine 10, and passed to the air separation device 200. Generate the necessary cold.
The cold fluid generated by adiabatic expansion in the expansion turbine 10 is cooled by the main heat exchanger 11 via the pipe 642 and then introduced into the first indirect heat exchanger 7.

  In the air separation method of the fourth embodiment, the high-pressure nitrogen gas fluid led out to the pipe 84 is boosted to a predetermined pressure by the compressor 35 and becomes a boosted nitrogen gas fluid. The pressurized nitrogen gas fluid is cooled by the main heat exchanger 11, depressurized to a predetermined pressure by the pressure reducing valve 29, and then introduced into the top of the high pressure column 4.

  Since the air separation method of the fourth embodiment using the air separation device 400 shown in FIG. 4 adiabatically expands part of the high-pressure nitrogen gas fluid, it is the same as the air separation method of the first embodiment described above. The effect of.

[Fifth Embodiment]
The air separation device of the fifth embodiment is an air separation device that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools raw material air to obtain a high-pressure raw material air fluid, The high pressure raw material air fluid is subjected to low temperature distillation to rectify and separate the high pressure nitrogen gas fluid at the top of the tower, the high pressure nitrogen enriched air fluid at the middle, and the high pressure oxygen enriched liquefied air fluid at the bottom of the tower; An expansion turbine that adiabatically expands a portion of the high-pressure nitrogen gas fluid to generate a cold fluid, the cold fluid, and a low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid, First indirect heat exchange in which the cryogenic fluid is condensed and liquefied to generate a low pressure liquefied gas fluid, and the low pressure oxygen enriched liquefied air fluid is evaporated to generate a low pressure oxygen enriched air fluid. And the low-pressure oxygen enrichment A low-pressure column for separating a gas fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through the expansion turbine; and pressurizing the low-pressure argon-enriched liquefied oxygen fluid After that, an argon tower that is separated into an argon gas fluid and a medium-pressure liquefied oxygen fluid by low-temperature distillation, and the argon gas fluid and the low-pressure liquefied oxygen fluid are indirectly heat-exchanged to condense and liquefy the argon gas fluid. A second indirect heat exchanger that generates an argon fluid and evaporates and vaporizes the low-pressure liquefied oxygen fluid to generate a low-pressure oxygen gas fluid; and indirectly heat-exchanges the high-pressure nitrogen gas fluid and the intermediate-pressure liquefied oxygen fluid. The high-pressure nitrogen gas fluid is condensed and liquefied to generate a high-pressure liquefied nitrogen fluid, and the intermediate-pressure liquefied oxygen fluid is evaporated to generate a medium-pressure oxygen gas fluid 3. Indirect heat exchanger, and part of the argon gas fluid, part of the liquefied argon fluid or argon gas fluid not liquefied in the second indirect heat exchanger A first product recovery line that is led out as a gas, a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid And a second product recovery line for deriving at least one fluid as a product.

FIG. 5 is a system diagram showing a schematic configuration of an air separation device according to a fourth embodiment of the present invention. In FIG. 5, the same components as those of the air separation devices 100, 200, 300, and 400 of the first to fourth embodiments shown in FIGS.
In the description of the fifth embodiment, “low pressure” refers to a pressure that is equal to or higher than the pressure of the product low-pressure nitrogen gas and lower than the operating pressure of the argon tower 6. “Medium pressure” refers to a pressure that is equal to or higher than the operating pressure of the argon tower 6 and lower than the pressure of the product high-pressure nitrogen gas. “High pressure” means a pressure higher than the pressure of the product high-pressure nitrogen gas.

  As shown in FIG. 5, the air separation device 500 of the fifth embodiment includes a second raw material air compressor 3, a pressure reducing valve 21, a pipe line 52, and a pipe that constitute the air separation device 100 of the first embodiment. The configuration is the same as that of the air separation device 100 except that the path 641 is excluded from the constituent elements and the pipe lines 80 and 86 are provided.

  One end of the pipe line 86 is connected to the lower part of the argon tower 6, and the other end is connected to the third product recovery pipe line 42. The pipe line 86 leads a part of the medium-pressure oxygen gas fluid in the argon tower 6 to the third product recovery pipe line 42. In the fifth embodiment, the third product recovery line 42 recovers a part of the medium-pressure oxygen gas fluid evaporated and evaporated in the third indirect heat exchanger 9 in the argon tower 6 as a product medium-pressure oxygen gas. It is a pipeline to do.

  The air separation device 500 of the fifth embodiment configured as described above has the same effects as the air separation device 300 of the first embodiment described above.

  In the air separation device 500 of the fifth embodiment configured as described above, the expansion turbine 10 adiabatically expands a part of the high-pressure nitrogen gas fluid to generate a cold fluid. Since the air separation device 500 of the fifth embodiment includes the first indirect heat exchanger 7 that indirectly heat-exchanges the cold fluid and the low-pressure oxygen-enriched liquefied air fluid after decompression, the first described above. There exists an effect similar to the air separation apparatus 100 of embodiment.

Hereinafter, the air separation method of the fifth embodiment will be described with reference to FIG.
The air separation method of the fifth embodiment is an air separation method that separates raw material air by a cryogenic separation method, and compresses, purifies, and cools the raw material air to obtain a high-pressure raw material air fluid; and A high-pressure separation step of separating the high-pressure raw material air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation; and a part of the high-pressure nitrogen gas fluid is adiabatically expanded. Adiabatic expansion step for generating a cryogenic fluid; indirect heat exchange between the cryogenic fluid and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid to condense the cryogenic fluid A first indirect heat exchange step for obtaining a low-pressure oxygen-enriched air fluid by evaporating and evaporating the low-pressure oxygen-enriched liquefied air fluid, and obtaining a low-pressure oxygen-enriched air fluid; Via A low-pressure separation step for separating the low-pressure nitrogen gas fluid, the low-pressure liquefied oxygen fluid, and the low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation, and pressurizing the low-pressure argon-enriched liquefied oxygen fluid, An argon separation step of separating the fluid into an intermediate pressure liquefied oxygen fluid, indirect heat exchange between the argon gas fluid and the low pressure liquefied oxygen fluid, condensing and liquefying the argon gas fluid to obtain a liquefied argon fluid, A second indirect heat exchange step of evaporating and evaporating the low pressure liquefied oxygen fluid to obtain a low pressure oxygen gas fluid, indirect heat exchange between the high pressure nitrogen gas fluid and the intermediate pressure liquefied oxygen fluid, and condensing and liquefying the high pressure nitrogen gas fluid To obtain a high-pressure liquefied nitrogen fluid and evaporate and vaporize the medium-pressure liquefied oxygen fluid to obtain a medium-pressure oxygen gas fluid; and the argon gas A first product recovery step of deriving at least one argon fluid as a product argon gas out of a part of the fluid, a part of the liquefied argon fluid, or an argon gas fluid not liquefied in the second indirect heat exchange step; A part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid or a part of the high-pressure liquefied nitrogen fluid as a product. And a second product recovery step.

  In the air separation method of the fifth embodiment, a part of the high-pressure nitrogen gas fluid at the top of the high-pressure tower 4 is led out to the pipe 80 via the pipe 53 and the pipe 54, and the high-pressure nitrogen gas fluid is extracted. Is introduced into the expansion turbine 10 from the pipe line 80 to generate the cold necessary for the air separation device 500, and the medium-pressure oxygen gas fluid in the argon tower 6 is passed through the pipe line 86. The medium pressure oxygen gas fluid is led out to the third product recovery line 42, the temperature is raised by indirect heat exchange in the main heat exchanger 11, and is led out from the third product recovery line 42 as product medium pressure oxygen gas. Except this, it can be performed by the same method as the air separation method of the first embodiment described above.

In the air separation method of the fifth embodiment, a part of the high-pressure nitrogen gas fluid at the top of the high-pressure tower 4 led to the pipe 53 is led to the second product recovery pipe 41 via the pipe 54. The The high-pressure nitrogen gas fluid led to the second product recovery pipe 41 is heated by the main heat exchanger 11.
A part of the high-pressure nitrogen gas fluid led out to the second product recovery pipe 41 and heated by the main heat exchanger 11 is adiabatically expanded by the expansion turbine 10 to generate the necessary cooling in the air separation device 500.
The cold fluid generated by adiabatic expansion in the expansion turbine 10 is heated in the main heat exchanger 11 through the pipe 642 and then introduced into the first indirect heat exchanger 7.
In the fifth embodiment, a part of the medium pressure oxygen gas fluid evaporated by the third indirect heat exchanger 9 in the argon tower 6 is led out to the pipe 86, and in the product through the third product recovery pipe 42. Derived as pressurized oxygen gas.

  Since the air separation method of the fifth embodiment using the air separation device 500 shown in FIG. 5 adiabatically expands part of the high-pressure nitrogen gas fluid, it is the same as the air separation method of the first embodiment described above. The effect of.

  FIG. 7 a is a schematic diagram showing the configuration and arrangement of a conventional air separation device 600. FIG. 7b is a schematic diagram showing the configuration and arrangement of the air separation devices 100, 200, 300, 400, 500 according to the first to fifth embodiments of the present invention.

  Comparing FIGS. 7 a and b, the first indirect heat exchanger 7 is disposed above the low pressure column 5 in both air separation apparatuses. In the conventional air separation device, the liquid pump 34 is necessary. However, in the present invention, it is not necessary to install the liquid pump 34. Therefore, the space can be saved as compared with the conventional one, and the cost, the installation area, and the power consumption can be reduced. A reductionable air separation device can be realized.

  According to the air separation method and the air separation device of at least one embodiment described above, the pressure in the first indirect heat exchanger outer cylinder 13 can be set to 130 kPaA. Thus, the high pressure oxygen enrichment of the first indirect heat exchanger outer cylinder 13 can be achieved without providing a liquid pump in the conduit 62 for feeding a part of the high pressure oxygen enriched liquefied air fluid led to the conduit 61. A liquefied air fluid can be delivered. Therefore, the equipment cost, installation space, and power for installing this liquid pump can be reduced.

  Although several embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments. Moreover, addition, omission, substitution, and other modifications of the configuration may be added to the present invention within the scope of the gist of the present invention described in the claims.

  100, 200, 300, 400, 500, 600 ... air separation device, 1 ... first raw material air compressor, 2 ... purifier, 3 ... second raw material air compressor, 4 .... High pressure column, 5 ... low pressure column, 6 ... argon column, 7 ... first indirect heat exchanger, 8 ... second indirect heat exchanger, 9 ... third indirect heat exchanger, DESCRIPTION OF SYMBOLS 10 ... Expansion turbine, 11 ... Main heat exchanger, 12 ... Supercooler, 13 ... 1st indirect heat exchanger outer cylinder, 14 ... 2nd indirect heat exchanger outer cylinder, 21-29 ... pressure reducing valve, 31, 32, 33, 34 ... liquid pump, 35 ... compressor, 41, 44, 45 ... second product recovery line, 42, 43 ... 3rd product recovery pipeline, 46 ... 1st product recovery pipeline, 50-63, 65-86, 641, 642 ... pipeline

Claims (4)

An air separation method for separating raw material air by a cryogenic separation method,
A raw material air compression process for compressing, purifying and cooling the raw material air to obtain a high pressure raw material air fluid;
A high-pressure separation step of separating the high-pressure raw material air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation;
Adiabatic expansion step of generating a cold fluid by adiabatic expansion of a part of the high-pressure nitrogen gas fluid;
Indirect heat exchange between the cryogenic fluid and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid, and condensing and liquefying the cryogenic fluid to obtain a low-pressure liquefied gas fluid A first indirect heat exchange step of evaporating and evaporating the low pressure oxygen-enriched liquefied air fluid to obtain a low-pressure oxygen-enriched air fluid;
Separating the low-pressure oxygen-enriched air fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through an expansion turbine; and
An argon separation step of pressurizing the low-pressure argon-enriched liquefied oxygen fluid and then separating it into an argon gas fluid and an intermediate-pressure liquefied oxygen fluid by low-temperature distillation;
Indirect heat exchange is performed between the argon gas fluid and the low-pressure liquefied oxygen fluid, the argon gas fluid is condensed and liquefied to obtain a liquefied argon fluid, and the low-pressure liquefied oxygen fluid is evaporated and vaporized to obtain a low-pressure oxygen gas fluid. 2 indirect heat exchange process;
The high-pressure nitrogen gas fluid and the medium-pressure liquefied oxygen fluid are indirectly heat-exchanged, the high-pressure nitrogen gas fluid is condensed and liquefied to obtain a high-pressure liquefied nitrogen fluid, and the medium-pressure liquefied oxygen fluid is evaporated and vaporized. A third indirect heat exchange step for obtaining an oxygen gas fluid;
A first product that derives at least one argon fluid as a product argon gas from among a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid that has not been liquefied in the second indirect heat exchange step. A recovery process;
At least one kind of fluid is derived as a product from a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid. A second product recovery process;
An air separation method comprising: An air separation method for separating raw material air by a cryogenic separation method,
A raw material air compression process for compressing, purifying and cooling the raw material air to obtain a high pressure raw material air fluid;
A high-pressure separation step of separating the high-pressure raw material air fluid into a high-pressure nitrogen gas fluid, a high-pressure nitrogen-enriched air fluid, and a high-pressure oxygen-enriched liquefied air fluid by low-temperature distillation;
An adiabatic expansion step of generating a cold fluid by adiabatically expanding either the part of the high-pressure raw material air fluid or the high-pressure nitrogen-enriched air fluid;
Indirect heat exchange between the cryogenic fluid and the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid, and condensing and liquefying the cryogenic fluid to obtain a low-pressure liquefied gas fluid A first indirect heat exchange step of evaporating and evaporating the low pressure oxygen-enriched liquefied air fluid to obtain a low-pressure oxygen-enriched air fluid;
Separating the low-pressure oxygen-enriched air fluid into a low-pressure nitrogen gas fluid, a low-pressure liquefied oxygen fluid, and a low-pressure argon-enriched liquefied oxygen fluid by low-temperature distillation without going through an expansion turbine; and
An argon separation step of pressurizing the low-pressure argon-enriched liquefied oxygen fluid and then separating it into an argon gas fluid and an intermediate-pressure liquefied oxygen fluid by low-temperature distillation;
Indirect heat exchange is performed between the argon gas fluid and the low-pressure liquefied oxygen fluid, the argon gas fluid is condensed and liquefied to obtain a liquefied argon fluid, and the low-pressure liquefied oxygen fluid is evaporated and vaporized to obtain a low-pressure oxygen gas fluid. 2 indirect heat exchange process;
The high-pressure nitrogen gas fluid and the medium-pressure liquefied oxygen fluid are indirectly heat-exchanged, the high-pressure nitrogen gas fluid is condensed and liquefied to obtain a high-pressure liquefied nitrogen fluid, and the medium-pressure liquefied oxygen fluid is evaporated and vaporized. A third indirect heat exchange step for obtaining an oxygen gas fluid;
A first product that derives at least one argon fluid as a product argon gas from among a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid that has not been liquefied in the second indirect heat exchange step. A recovery process;
At least one kind of fluid is derived as a product from a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid. A second product recovery process;
An air separation method comprising: An air separation device for separating raw material air by a cryogenic separation method,
Raw material air pretreatment equipment that compresses, purifies, and cools raw material air to obtain a high pressure raw material air fluid; and
A high-pressure column for rectifying and separating the high-pressure feed air fluid into a high-pressure nitrogen gas fluid at the top of the column, a high-pressure nitrogen-enriched air fluid at the middle, and a high-pressure oxygen-enriched liquefied air fluid at the bottom of the column,
An expansion turbine that generates a cold fluid by adiabatically expanding a portion of the high-pressure nitrogen gas fluid;
The cold fluid is indirectly heat exchanged with the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid, and the cold fluid is condensed and liquefied to generate a low-pressure liquefied gas fluid. And a first indirect heat exchanger that evaporates and vaporizes the low-pressure oxygen-enriched liquefied air fluid to produce a low-pressure oxygen-enriched air fluid;
A low pressure column that separates the low pressure oxygen enriched air fluid into a low pressure nitrogen gas fluid, a low pressure liquefied oxygen fluid, and a low pressure argon enriched liquefied oxygen fluid by low temperature distillation without going through the expansion turbine;
An argon tower that pressurizes the low-pressure argon-enriched liquefied oxygen fluid and then separates it into an argon gas fluid and an intermediate-pressure liquefied oxygen fluid by low-temperature distillation;
The argon gas fluid and the low-pressure liquefied oxygen fluid are indirectly heat-exchanged, and the argon gas fluid is condensed and liquefied to generate a liquefied argon fluid, and the low-pressure liquefied oxygen fluid is evaporated and vaporized to generate a low-pressure oxygen gas fluid. A second indirect heat exchanger,
The high-pressure nitrogen gas fluid and the medium-pressure liquefied oxygen fluid are indirectly heat-exchanged, the high-pressure nitrogen gas fluid is condensed and liquefied to generate a high-pressure liquefied nitrogen fluid, and the medium-pressure liquefied oxygen fluid is evaporated and evaporated. A third indirect heat exchanger generating a pressurized oxygen gas fluid;
A first product that derives at least one argon fluid as product argon gas from among a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid that has not been liquefied by the second indirect heat exchanger A recovery line;
At least one kind of fluid is derived as a product from a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid. A second product recovery line;
An air separation device comprising: An air separation device for separating raw material air by a cryogenic separation method,
Raw material air pretreatment equipment that compresses, purifies, and cools raw material air to obtain a high pressure raw material air fluid; and
A high-pressure column for rectifying and separating the high-pressure feed air fluid into a high-pressure nitrogen gas fluid at the top of the column, a high-pressure nitrogen-enriched air fluid at the middle, and a high-pressure oxygen-enriched liquefied air fluid at the bottom of the column,
An expansion turbine that adiabatically expands either one of the high-pressure feed air fluid or the high-pressure nitrogen-enriched air fluid to generate a cold fluid;
The cold fluid is indirectly heat exchanged with the low-pressure oxygen-enriched liquefied air fluid obtained by depressurizing the high-pressure oxygen-enriched liquefied air fluid, and the cold fluid is condensed and liquefied to generate a low-pressure liquefied gas fluid. And a first indirect heat exchanger that evaporates and vaporizes the low-pressure oxygen-enriched liquefied air fluid to produce a low-pressure oxygen-enriched air fluid;
A low pressure column that separates the low pressure oxygen enriched air fluid into a low pressure nitrogen gas fluid, a low pressure liquefied oxygen fluid, and a low pressure argon enriched liquefied oxygen fluid by low temperature distillation without going through the expansion turbine;
An argon tower that pressurizes the low-pressure argon-enriched liquefied oxygen fluid and then separates it into an argon gas fluid and an intermediate-pressure liquefied oxygen fluid by low-temperature distillation;
The argon gas fluid and the low-pressure liquefied oxygen fluid are indirectly heat-exchanged, and the argon gas fluid is condensed and liquefied to generate a liquefied argon fluid, and the low-pressure liquefied oxygen fluid is evaporated and vaporized to generate a low-pressure oxygen gas fluid. A second indirect heat exchanger,
The high-pressure nitrogen gas fluid and the medium-pressure liquefied oxygen fluid are indirectly heat-exchanged, the high-pressure nitrogen gas fluid is condensed and liquefied to generate a high-pressure liquefied nitrogen fluid, and the medium-pressure liquefied oxygen fluid is evaporated and evaporated. A third indirect heat exchanger generating a pressurized oxygen gas fluid;
A first product that derives at least one argon fluid as product argon gas from among a part of the argon gas fluid, a part of the liquefied argon fluid, or an argon gas fluid that has not been liquefied by the second indirect heat exchanger A recovery line;
At least one kind of fluid is derived as a product from a part of the low-pressure liquefied oxygen fluid, a part of the medium-pressure liquefied oxygen fluid, a part of the high-pressure nitrogen gas fluid, or a part of the high-pressure liquefied nitrogen fluid. A second product recovery line;
An air separation device comprising:

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