EP0042676A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for producing gaseous oxygen and a cryogenic plant in which said method can be carried out
Assignee: Air Products and Chemicals Inc
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Filing: 1981-06-02
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Granted: —
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Expires: 2001-06-02
Abstract
Abstract A method for producing gaseous oxygen, preferably at pressures in excess of 35 bars A, by the fractional distillation of air using a conventional double column having a high pressure column (6) and a low pressure column (11). Liquid oxygen is withdrawn from the bottom of the low pressure column (11) and is pressurized to just above the desired product pressure by pump (13). The liquid oxygen is then vapourized in heat exchanger (15) using nitrogen from the top of the high pressure column (6). The nitrogen is compressed in compressor (28) to 41 bars A and in compressors (32 and 34) to 80 bars A. The stream (35) is sub-cooled in heat exchanger 15 and, after expansion at valve (36), the liquid nitrogen is returned to the high pressure column as reflux. The stream (31) is cooled in heat exchanger (15) and is expanded in an expander (40). The gas leaving the expander (40) is used to cool the stream (35) in heat exchanger (15) and is subsequently recycled to the inlet of compressor 28.
Inventors
- 👤 Alan Theobald
- 👤 Brian Alfred Mcneil
- 👤 Rodney John Allam
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 00:40
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/04; F25J3/04006; F25J3/04078; F25J3/0409; F25J3/04151; F25J3/04187; F25J3/04218; F25J3/04224; F25J3/04248; F25J3/04333; F25J3/04351; F25J3/04357; F25J3/04375; F25J3/04406; F25J3/04412; F25J2205/00; F25J2205/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
177 words
A method for producing gaseous oxygen which method comprises the steps of fractionating dry compressed air in a double distillation column having a high pressure column operating at between 5 and 9 bars absolute and a low pressure column operating at between 1.3 and 3 bars absolute, wherein liquid oxygen is withdrawn from the bottom of the low pressure column, is pressurized and is evaporated against a stream of nitrogen rich gas which has been removed from the high pressure column and compressed in a compressor characterized in that the compressed nitrogen rich gas is divided into a first sub-stream and a second sub-stream; the first sub-stream is cooled against the vaporising liquid oxygen and is then expanded to produce a mainly (on a molar basis) liquid product at least part of which is returned to the high pressure column as reflux; and the second sub-stream is cooled, expanded in an expander, and at least part of the product leaving the expander is used to assist cooling the first sub-stream and is then recycled to said compressor.
Claim 2
Independent Claim
177 words
A method for producing gaseous oxygen which method comprises the steps of fractionating dry compressed air in a double distillation column having a high pressure column operating at between 5 and 9 bars absolute and a low pressure column operating at between 1.3 and 3 bars absolute, wherein liquid oxygen is withdrawn from the bottom of the low pressure column, is pressurized and is evaporated against a stream of nitrogen rich gas which has been removed from the high pressure column and compressed in a compressor characterized in that the compressed nitrogen rich gas is divided into a first sub-stream and a second sub-stream; the first sub-stream is cooled against the vaporising liquid oxygen and is then expanded to produce a mainly (on a molar basis) liquid product at least part of which is returned to the high pressure column as reflux; and the second sub-stream is cooled, expanded in an expander, and at least part of the product leaving the expander is used to assist cooling the first sub-stream and is then recycled to said compressor.
Claim 3
Independent Claim
177 words
A method for producing gaseous oxygen which method comprises the steps of fractionating dry compressed air in a double distillation column having a high pressure column operating at between 5 and 9 bars absolute and a low pressure column operating at between 1.3 and 3 bars absolute, wherein liquid oxygen is withdrawn from the bottom of the low pressure column, is pressurized and is evaporated against a stream of substantially pure nitrogen which has been removed from the top of the high pressure column and compressed in a compressor characterized in that the compressed nitrogen is divided into a first sub-stream and a second sub-stream; the first sub-stream is cooled against the vaporising liquid oxygen and is then expanded to produce a mainly (on a molar basis) liquid product at least part of which is returned to the high pressure column as reflux; and the second sub-stream is cooled, expanded in an expander, and at least part of the product leaving the expander is used to assist cooling the first sub-stream.and is then recycled to said compressor.
Claim 4
Independent Claim
177 words
A method for producing gaseous oxygen which method comprises the steps of fractionating dry compressed air in a double distillation column having a high pressure column operating at between 5 and 9 bars absolute and a low pressure column operating at between 1.3 and 3 bars absolute, wherein liquid oxygen is withdrawn from the bottom of the low pressure column, is pressurized and is evaporated against a stream of substantially pure nitrogen which has been removed from the top of the high pressure column and compressed in a compressor characterized in that the compressed nitrogen is divided into a first sub-stream and a second sub-stream; the first sub-stream is cooled against the vaporising liquid oxygen and is then expanded to produce a mainly (on a molar basis) liquid product at least part of which is returned to the high pressure column as reflux; and the second sub-stream is cooled, expanded in an expander, and at least part of the product leaving the expander is used to assist cooling the first sub-stream.and is then recycled to said compressor.
Claim 5
Dependent Claim
24 words
A method according to Claim 1 or 2, characterized in that the first sub-stream is compressed to a higher pressure than the second sub-stream.
Claim 6
Dependent Claim
24 words
A method according to Claim 1 or 2, characterized in that said second sub-stream leaving said expander contains up to 15 mole percent liquid.
Claim 7
Dependent Claim
26 words
A method according to Claim 1, 2, 3 or 4, characterized in that the pressure of said first sub-stream is in excess of 40 bars absolute.
Claim 8
Dependent Claim
27 words
A method according to Claim 1, 2, 3, 4, or 5, characterized in that the pressure of said second sub-stream is in excess of 30 bars absolute.
Claim 9
Dependent Claim
217 words
A cryogenic plant for producing gaseous oxygen, which plant comprises a high pressure column and a low pressure column for distilling air, a heat exchanger in which liquid oxygen can evaporate, a pump for, in use, receiving liquid oxygen from the bottom of said low pressure column and introducing it into said heat exchanger, compressor, a conduit for carrying nitrogen rich gas from said .high pressure column to said compressor, a conduit for conveying a first sub-stream of compressed nitrogen rich gas from said compressor through said heat exchanger in countercurrent flow to said liquid oxygen, an expansion .valve for, in use, expanding cold nitrogen rich gas leaving said heat exchanger and a conduit for conveying liquified nitrogen rich gas from said expansion valve to said high pressure column, characterized in that a further conduit is provided for conveying a second sub-stream of compressed nitrogen rich gas from said compressor to said heat exchanger to cool said compressed nitrogen rich gas, an expander for allowing compressed nitrogen rich gas from said heat exchanger to expand, a conduit for conveying nitrogen rich gas from said expander to said heat exchanger to assist in cooling said first sub-stream of compressed nitrogen rich gas and a conduit for carrying said nitrogen rich gas from said heat exchanger to said compressor.
Claim 10
Dependent Claim
217 words
A cryogenic plant for producing gaseous oxygen, which plant comprises a high pressure column and a low pressure column for distilling air, a heat exchanger in which liquid oxygen can evaporate, a pump for, in use, receiving liquid oxygen from the bottom of said low pressure column and introducing it into said heat exchanger, compressor, a conduit for carrying nitrogen rich gas from said .high pressure column to said compressor, a conduit for conveying a first sub-stream of compressed nitrogen rich gas from said compressor through said heat exchanger in countercurrent flow to said liquid oxygen, an expansion .valve for, in use, expanding cold nitrogen rich gas leaving said heat exchanger and a conduit for conveying liquified nitrogen rich gas from said expansion valve to said high pressure column, characterized in that a further conduit is provided for conveying a second sub-stream of compressed nitrogen rich gas from said compressor to said heat exchanger to cool said compressed nitrogen rich gas, an expander for allowing compressed nitrogen rich gas from said heat exchanger to expand, a conduit for conveying nitrogen rich gas from said expander to said heat exchanger to assist in cooling said first sub-stream of compressed nitrogen rich gas and a conduit for carrying said nitrogen rich gas from said heat exchanger to said compressor.
Claim 11
Dependent Claim
221 words
A cryogenic plant for producing gaseous oxygen, which plant comprises a high pressure column and a low pressure column for distilling air, a heat exchanger in which liquid oxygen can evaporate, a pump for, in use, receiving liquid oxygen from the bottom of said low pressure column and introducing it into said heat exchanger, a compressor, a conduit for carrying substantially pure gaseous nitrogen from the top of said high pressure column to said compressor, a conduit for conveying a first sub-stream of substantially pure compressed nitrogen from said compressor through said heat exchanger in countercurrent flow to said liquid oxygen, an expansion valve for, in use, expanding substantially pure cold nitrogen leaving said heat exchanger and a conduit for conveying substantially pure liquid nitrogen from said expansion valve to said high pressure column, characterized in that a further conduit is provided for conveying ssecond sub-stream of substantially pure compressed nitrogen from said compressor to said heat exchanger to cool said compressed nitrogen, an expander for allowing substantially pure compressed nitrogen from said heat exchanger to expand, a conduit for conveying substantially pure gaseous nitrogen from said expander to said heat exchanger to assist in cooling said first sub-stream of substantually pure compressed nitrogen and a conduit for carrying said substantially pure gaseous nitrogen from said heat exchanger to said compressor.
Claim 12
Dependent Claim
221 words
A cryogenic plant for producing gaseous oxygen, which plant comprises a high pressure column and a low pressure column for distilling air, a heat exchanger in which liquid oxygen can evaporate, a pump for, in use, receiving liquid oxygen from the bottom of said low pressure column and introducing it into said heat exchanger, a compressor, a conduit for carrying substantially pure gaseous nitrogen from the top of said high pressure column to said compressor, a conduit for conveying a first sub-stream of substantially pure compressed nitrogen from said compressor through said heat exchanger in countercurrent flow to said liquid oxygen, an expansion valve for, in use, expanding substantially pure cold nitrogen leaving said heat exchanger and a conduit for conveying substantially pure liquid nitrogen from said expansion valve to said high pressure column, characterized in that a further conduit is provided for conveying ssecond sub-stream of substantially pure compressed nitrogen from said compressor to said heat exchanger to cool said compressed nitrogen, an expander for allowing substantially pure compressed nitrogen from said heat exchanger to expand, a conduit for conveying substantially pure gaseous nitrogen from said expander to said heat exchanger to assist in cooling said first sub-stream of substantually pure compressed nitrogen and a conduit for carrying said substantially pure gaseous nitrogen from said heat exchanger to said compressor.
Claim 13
Dependent Claim
224 words
A cryogenic plant for producing gaseous oxygen which plant comprises a high pressure column and a low pressure column for distilling air, a first heat exchanger in which liquid oxygen can evaporate, a pump for, in use, receiving liquid oxygen from the bottom of said low pressure column and introducing it into said first heat exchanger, a compressor, a conduit for carrying nitrogen rich gas from said high pressure column to said compressor, a conduit f.or conveying a first sub-stream of compressed nitrogen rich gas from said compressor through said first heat exchanger in countercurrent flow to said liquid oxygen, an expansion valve for, in use, expanding cold nitrogen rich gas leaving said heat exchanger and a conduit for conveying liquified nitrogen rich gas from said expansion valve to said high pressure column, characterized in that a further conduit is provided for conveying a second sub-stream of compressed nitrogen rich gas from said compressor to a second heat exchanger to cool said compressed nitrogen rich gas, an expander -for allowing compressed nitrogen rich gas from said second heat exchanger to expand, a conduit for conveying nitrogen rich.gas from said expander to said first heat exchanger to assist in cooling said first sub-stream of compressed nitrogen rich gas, and a conduit for carrying said nitrogen rich gas from said first heat exchanger to said compressor.
Claim 14
Dependent Claim
224 words
A cryogenic plant for producing gaseous oxygen which plant comprises a high pressure column and a low pressure column for distilling air, a first heat exchanger in which liquid oxygen can evaporate, a pump for, in use, receiving liquid oxygen from the bottom of said low pressure column and introducing it into said first heat exchanger, a compressor, a conduit for carrying nitrogen rich gas from said high pressure column to said compressor, a conduit f.or conveying a first sub-stream of compressed nitrogen rich gas from said compressor through said first heat exchanger in countercurrent flow to said liquid oxygen, an expansion valve for, in use, expanding cold nitrogen rich gas leaving said heat exchanger and a conduit for conveying liquified nitrogen rich gas from said expansion valve to said high pressure column, characterized in that a further conduit is provided for conveying a second sub-stream of compressed nitrogen rich gas from said compressor to a second heat exchanger to cool said compressed nitrogen rich gas, an expander -for allowing compressed nitrogen rich gas from said second heat exchanger to expand, a conduit for conveying nitrogen rich.gas from said expander to said first heat exchanger to assist in cooling said first sub-stream of compressed nitrogen rich gas, and a conduit for carrying said nitrogen rich gas from said first heat exchanger to said compressor.
Claim 15
Dependent Claim
230 words
A cryogenic plant for producing gaseous oxygen which plant comprises a high pressure column and a low pressure column for distilling air, a first heat exchanger in which liquid oxygen can evaporate, a pump for, in use, receiving liquid oxygen from the bottom of said low pressure column and introducing it into said first heat exchanger, a compressor, a conduit for carrying substantially pure gaseous nitrogen from the top of said high pressure column to said compressor, a conduit for conveying a first sub-stream of substantially pure compressed nitrogen from said compressor through said first heat exchanger in countercurrent flow to said liquid oxygen, an expansion valve for, in use, expanding substantially pure cold nitrogen leaving said heat exchanger and a conduit for conveying substantially pure liquid nitrogen from said expansion valve to said high pressure column, characterized in that further conduit is provided for conveying a second sub-stream of substantially pure compressed nitrogen from said compressor to a second heat exchanger to cool said substantially pure compressed nitrogen, an expander for allowing substantially pure compressed nitrogen from said second heat exchanger to expand, a conduit for conveying substantially pure gaseous nitrogen from said expander to said first heat exchanger to assist in cooling said first sub-stream of substantially pure compressed nitrogen, and a conduit for carrying said substantially pure gaseous nitrogen from said first heat exchanger to said compressor.
Claim 16
Dependent Claim
230 words
A cryogenic plant for producing gaseous oxygen which plant comprises a high pressure column and a low pressure column for distilling air, a first heat exchanger in which liquid oxygen can evaporate, a pump for, in use, receiving liquid oxygen from the bottom of said low pressure column and introducing it into said first heat exchanger, a compressor, a conduit for carrying substantially pure gaseous nitrogen from the top of said high pressure column to said compressor, a conduit for conveying a first sub-stream of substantially pure compressed nitrogen from said compressor through said first heat exchanger in countercurrent flow to said liquid oxygen, an expansion valve for, in use, expanding substantially pure cold nitrogen leaving said heat exchanger and a conduit for conveying substantially pure liquid nitrogen from said expansion valve to said high pressure column, characterized in that further conduit is provided for conveying a second sub-stream of substantially pure compressed nitrogen from said compressor to a second heat exchanger to cool said substantially pure compressed nitrogen, an expander for allowing substantially pure compressed nitrogen from said second heat exchanger to expand, a conduit for conveying substantially pure gaseous nitrogen from said expander to said first heat exchanger to assist in cooling said first sub-stream of substantially pure compressed nitrogen, and a conduit for carrying said substantially pure gaseous nitrogen from said first heat exchanger to said compressor.
Claim 17
Dependent Claim
33 words
ll. A cryogenic plant according to Claim 9 or 10, characterized in that said first heat exchanger is a wound coil heat exchanger and said second heat exchanger is a plate-fin heat exchanger.
References Cited (Backward Citations)
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