US4957524A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air separation process with improved reboiler liquid cleaning circuit
Assignee: Praxair Technology Inc
•
Filing: 1989-05-15
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Granted: 1990-09-18
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Expires: 2009-05-15
Abstract
Abstract A cryogenic rectification method wherein liquid from a top condenser-reboiler is cleaned of higher boiling impurities by passage through an adsorbent bed and returned to the condenser-reboiler, wherein the flow back to the condenser-reboiler is driven by combination with density-reducing vapor.
Inventors
- 👤 Ravindra F. Pahade
- 👤 John H. Ziemer
- 👤 John K. Howell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:52
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/04; F25J3/04763; F25J3/04769; F25J3/04793; F25J3/04248; F25J3/04284; F25J3/0429; F25J3/044; F25J3/04406; F25J3/04412; F25J3/04854; F25J3/0486; F25J2200/00; F25J2200/50; F25J2200/54; F25J2205/00; F25J2205/60; F25J2215/00; F25J2215/40; F25J2235/00; F25J2235/06; F25J2245/00; F25J2245/50; Y; Y10; Y10S; Y10S62/00; Y10S62/902; Y10S62/908
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
109 words
A method for cryogenic separation comprising: (A) separating a feed comprising nitrogen, oxygen and higher boiling impurities, in a column having a top condenser-reboiler, into nitrogen-richer vapor and oxygen-enriched liquid containing higher boiling impurities; (B) passing oxygen-enriched liquid from the column to the top condenser-reboiler; (C) passing oxygen-enriched liquid from the top condenser-reboiler through an adsorbent bed, transferring higher boiling impurities from the liquid to the adsorbent, and returning resulting cleaned liquid to the top condenser-reboiler; and (D) driving the liquid back to the top condenser-reboiler, at least in part, by combining the liquid with vapor to reduce the density of the stream passing back to the top condenser-reboiler.
Claim 2
Independent Claim
109 words
A method for cryogenic separation comprising: (A) separating a feed comprising nitrogen, oxygen and higher boiling impurities, in a column having a top condenser-reboiler, into nitrogen-richer vapor and oxygen-enriched liquid containing higher boiling impurities; (B) passing oxygen-enriched liquid from the column to the top condenser-reboiler; (C) passing oxygen-enriched liquid from the top condenser-reboiler through an adsorbent bed, transferring higher boiling impurities from the liquid to the adsorbent, and returning resulting cleaned liquid to the top condenser-reboiler; and (D) driving the liquid back to the top condenser-reboiler, at least in part, by combining the liquid with vapor to reduce the density of the stream passing back to the top condenser-reboiler.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein the column is the lower pressure column of a double column air separation method.
Claim 4
Dependent Claim
23 words
The method of claim 2 wherein vapor from the higher pressure column forms at least part of the density-reducing vapor of step (D).
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein the column is the column of a single column air separation method.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein the column contains a second condenser-reboiler at the bottom of the column.
Claim 7
Dependent Claim
28 words
The method of claim 5 wherein vapor from the second condenser-reboiler at the bottom of the column forms at least part of the density-reducing vapor of step (D).
Claim 8
Dependent Claim
16 words
The method of claim 1 wherein the adsorbent bed comprises silica gel, alumina and/or molecular sieve.
Claim 9
Dependent Claim
25 words
The method of claim 1 wherein the oxygen-enriched liquid is passed from the top condenser-reboiler to the adsorbent bed, at least in part, by gravity.
Claim 10
Dependent Claim
24 words
The method of claim 1 wherein vapor is removed from the column and forms at least part of the density-reducing vapor of step (D).
Claim 11
Dependent Claim
20 words
The method of claim 1 wherein column feed vapor forms at least part of the density-reducing vapor of step (D).
Claim 12
Dependent Claim
18 words
The method of claim 1 wherein air forms at least part of the density-reducing vapor of step (D).
Claim 13
Independent Claim
109 words
A method for cryogenic separation comprising: (A) separating a feed comprising nitrogen, oxygen and higher boiling impurities, in a column having a top condenser-reboiler, into nitrogen-richer vapor and oxygen-enriched liquid containing higher boiling impurities; (B) passing oxygen-enriched liquid from the column to the top condenser-reboiler; (C) passing oxygen-enriched liquid from the top condenser-reboiler through an adsorbent bed, transferring higher boiling impurities from the liquid to the adsorbent, and returning resulting cleaned liquid to the top condenser-reboiler; and (D) driving the liquid back to the top condenser-reboiler, at least in part, by vaporizing some of this liquid to reduce the density of the stream passing back to the to condenser-reboiler.
Claim 14
Independent Claim
109 words
A method for cryogenic separation comprising: (A) separating a feed comprising nitrogen, oxygen and higher boiling impurities, in a column having a top condenser-reboiler, into nitrogen-richer vapor and oxygen-enriched liquid containing higher boiling impurities; (B) passing oxygen-enriched liquid from the column to the top condenser-reboiler; (C) passing oxygen-enriched liquid from the top condenser-reboiler through an adsorbent bed, transferring higher boiling impurities from the liquid to the adsorbent, and returning resulting cleaned liquid to the top condenser-reboiler; and (D) driving the liquid back to the top condenser-reboiler, at least in part, by vaporizing some of this liquid to reduce the density of the stream passing back to the to condenser-reboiler.
Claim 15
Dependent Claim
23 words
The method of claim 12 wherein the partial vaporization of the oxygen-enriched liquid is achieved by reducing the pressure of the oxygen-enriched liquid.
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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) | 1993-09-17 | 1994-03-19 | 1994-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-17 | 1998-03-19 | 1998-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-17 | 2002-03-19 | 2002-09-18 | $7700.00 | Window Closed / Lapsed |