US4099945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Efficient air fractionation
Assignee: Linde GmbH
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Filing: 1976-10-27
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Granted: 1978-07-11
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Expires: 1996-10-27
Abstract
Abstract In a process for the fractionation of air wherein the air is subjected to rectification in a high-pressure column and a low pressure column, wherein in a liquefaction cycle, nitrogen is withdrawn in the gaseous phase from the head of the high-pressure column and is liquefied by heating, compression, recooling, and expansion and recycled as liquid to the high-pressure column and wherein a gas, e.g., air is withdrawn from the high pressure column, is preheated, and is then expanded through a low-pressure expansion turbine, the improvement which comprises cooling the gas expanded in the low-pressure expansion turbine in indirect heat exchange with at least a portion of the nitrogen which is heated in the liquefaction cycle.
Inventors
- 👤 Werner Skolaude
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:55
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/04; F25J3/04248; F25J3/04284; F25J3/0429; F25J3/04303; F25J3/04151; F25J3/04187; F25J3/04193; F25J3/04218; F25J3/04224; F25J3/04278; F25J3/04309; F25J3/04333; F25J3/04351; F25J3/04357; F25J3/04375; F25J3/04393; F25J3/04406; F25J3/04412; F25J2270/00; F25J2270/90; F25J2290/00; F25J2290/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
128 words
In a process for the fractionation of air wherein the air is subjected to rectification in a high pressure column and a low pressure column, wherein in a liquefaction cycle, a first stream of nitrogen is withdrawn in the gaseous phase from the head of the high-pressure column and is heated, compressed and recooled then liquefied by expansion and recycled as liquid to the high-pressure column and wherein a second gaseous stream containing nitrogen is derived from the high pressure column, is preheated and is then expanded through a low-pressure expansion turbine, the improvement which comprises cooling the second gaseous stream expanded in the low-pressure expansion turbine in an indirect heat exchange step with at least a portion of the first stream being heated in the liquefaction cycle.
Claim 2
Dependent Claim
128 words
In a process for the fractionation of air wherein the air is subjected to rectification in a high pressure column and a low pressure column, wherein in a liquefaction cycle, a first stream of nitrogen is withdrawn in the gaseous phase from the head of the high-pressure column and is heated, compressed and recooled then liquefied by expansion and recycled as liquid to the high-pressure column and wherein a second gaseous stream containing nitrogen is derived from the high pressure column, is preheated and is then expanded through a low-pressure expansion turbine, the improvement which comprises cooling the second gaseous stream expanded in the low-pressure expansion turbine in an indirect heat exchange step with at least a portion of the first stream being heated in the liquefaction cycle.
Claim 3
Dependent Claim
28 words
A process according to claim 1 wherein the second gaseous stream expanded in the low-pressure expansion turbine is air withdrawn from the bottom portion of the high-pressure column.
Claim 4
Dependent Claim
23 words
A process according to claim 2, further comprising passing resultant cooled air withdrawn from said indirect heat exchange step to the low-pressure column.
Claim 5
Dependent Claim
18 words
A process according to claim 3, wherein said resultant cooled air is passed directly to said low-pressure column.
Claim 6
Dependent Claim
17 words
A process according to claim 3, wherein the low pressure expansion turbine is operated at 170°-185° K.
Claim 7
Dependent Claim
17 words
A process according to claim 2, wherein the low pressure expansion turbine is operated at 170°-185° K.
Claim 8
Dependent Claim
17 words
A process according to claim 1, wherein the low pressure expansion turbine is operated at 170°-185° K.
Claim 9
Dependent Claim
52 words
A process according to claim 1, wherein said first stream containing nitrogen is split into a first part and a second part directly after withdrawal from the head of the high pressure column, and said first part is passed directly to said indirect heat exchange step for cooling said expanded gasoues stream.
Claim 10
Dependent Claim
66 words
A process according to claim 8, wherein said second part of said first stream is heated, compressed and recooled in said liquefaction cycle and prior to the expansion of the recooled second part, a portion of said recooled second part is branched therefrom, turbine-expanded to the pressure of the high-pressure column, and passed to said indirect heat exchange step for cooling said expanded second gaseous stream.
Claim 11
Dependent Claim
19 words
A process according to claim 1 wherein the second gaseous stream expanded in the low-pressure expansion turbine is nitrogen.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-10 | 1982-01-09 | 1982-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-10 | 1986-01-09 | 1986-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-10 | 1990-01-09 | 1990-07-11 | $7700.00 | Window Closed / Lapsed |