US5133790A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryogenic rectification method for producing refined argon
Assignee: Praxair Technology Inc
•
Filing: 1991-06-24
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Granted: 1992-07-28
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Expires: 2011-06-24
Abstract
Abstract A cryogenic rectification method employing rectification over a defined height within the lower pressure column of a double column system which reduces the nitrogen concentration of an argon, nitrogen, oxygen mixture while maintaining the argon concentration at or near its maximum enabling production of nitrogen-free argon directly from the argon column system.
Inventors
- 👤 John R. Bianchi
- 👤 Dante P. Bonaquist
- 👤 Richard A. Victor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:33
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/04; F25J3/04642; F25J3/04648; F25J3/04721; F25J3/04151; F25J3/04187; F25J3/04193; F25J3/04248; F25J3/04284; F25J3/0429; F25J3/04303; F25J3/04406; F25J3/04412; F25J3/04624; F25J3/04654; F25J3/04666; F25J3/04672; F25J3/04678; F25J2200/00; F25J2200/90; F25J2245/00; F25J2245/58; F25J2290/00; F25J2290/10; Y; Y10; Y10S; Y10S62/00; Y10S62/923; Y10S62/924; Y10S62/939
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
150 words
A method for producing nitrogen-free argon comprising: (a) separating a feed comprising argon, nitrogen and oxygen by cryogenic distillation in a double column system comprising a higher pressure column and a lower pressure column; (b) withdrawing a fluid stream from the lower pressure column and passing this stream as argon column feed into an argon column system; (c) operating the lower pressure column with sufficient equilibrium stages comprising packing above the point where the argon column feed is withdrawn from the lower pressure column so that the withdrawal of the argon column feed from the lower pressure column occurs at least 5 equilibrium stages below where the argon concentration in the lower pressure column is at a maximum and the nitrogen concentration in the argon column feed is less than 50 ppm; and (d) recovering directly from the argon column system argon having a nitrogen concentration not exceeding 10 ppm.
Claim 2
Independent Claim
150 words
A method for producing nitrogen-free argon comprising: (a) separating a feed comprising argon, nitrogen and oxygen by cryogenic distillation in a double column system comprising a higher pressure column and a lower pressure column; (b) withdrawing a fluid stream from the lower pressure column and passing this stream as argon column feed into an argon column system; (c) operating the lower pressure column with sufficient equilibrium stages comprising packing above the point where the argon column feed is withdrawn from the lower pressure column so that the withdrawal of the argon column feed from the lower pressure column occurs at least 5 equilibrium stages below where the argon concentration in the lower pressure column is at a maximum and the nitrogen concentration in the argon column feed is less than 50 ppm; and (d) recovering directly from the argon column system argon having a nitrogen concentration not exceeding 10 ppm.
Claim 3
Dependent Claim
38 words
The method of claim 1 wherein the withdrawal of the argon column feed from the lower pressure column occurs at least 10 equilibrium stages below where the argon concentration in the lower pressure column is at a maximum.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the nitrogen concentration in the argon column feed is less than 10 ppm.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein the nitrogen concentration in the argon column feed is less than 1 ppm.
Claim 6
Dependent Claim
19 words
The method of claim 1 wherein the argon concentration in the argon column feed is at least 7 percent.
Claim 7
Dependent Claim
11 words
The method of claim 1 wherein the packing comprises structured packing.
Claim 8
Dependent Claim
11 words
The method of claim 1 wherein the packing comprises random packing.
Claim 9
Dependent Claim
23 words
The method of claim 1 wherein the argon recovered directly from the argon column system has a nitrogen concentration not exceeding 5 ppm.
Claim 10
Dependent Claim
23 words
The method of claim 1 wherein the argon recovered directly from the argon column system has a nitrogen concentration not exceeding 2 ppm.
Claim 11
Dependent Claim
17 words
The method of claim 1 wherein the argon recovered directly from the argon column system comprises vapor.
Claim 12
Dependent Claim
17 words
The method of claim 1 wherein the argon recovered directly from the argon column system comprises liquid.
Claim 13
Dependent Claim
33 words
The method of claim 1 further comprising removing from the argon column system a waste stream at least one equilibrium stage above where the argon is recovered directly from the argon column system.
Claim 14
Dependent Claim
17 words
The method of claim 12 wherein the waste stream is recycled back into the double column system.
Claim 15
Dependent Claim
22 words
The method of claim 1 further comprising operating the argon column of the argon column system with at least 150 equilibrium stages.
Claim 16
Dependent Claim
15 words
The method of claim 14 wherein the equilibrium stages in the argon column comprise packing.
Claim 17
Dependent Claim
26 words
The method of claim 14 wherein the argon recovered directly from the argon column system is refined argon having an oxygen concentration not exceeding 10 ppm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-28 | 1996-01-27 | 1996-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-28 | 2000-01-27 | 2000-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-28 | 2004-01-27 | 2004-07-28 | $7700.00 | Window Closed / Lapsed |