US4565685A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air separation with temperature and pressure swing
Assignee: Air Products and Chemicals Inc
•
Filing: 1984-09-14
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Granted: 1986-01-21
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Expires: 2004-09-14
Abstract
Abstract A chemical absorbent air separation process is set forth which uses a temperature swing absorption-desorption cycle in combination with a pressure swing wherein the pressure is elevated in the desorption stage of the process.
Inventors
- 👤 Anthony A. Cassano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:51
CPC Classifications
C; C01; C01B; C01B13/00; B; B01; B01D; B01D53/00; B01D53/14; B01D53/1493; C01B13/02; C01B13/0292; C01B21/00; C01B21/04; C01B21/0405; C01B21/0411; C01B2210/00; C01B2210/0043; C01B2210/0045
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
119 words
A continuous process for separating air into oxygen and nitrogen comprising the repeated steps of contacting feed air with an oxygen acceptor mixture of alkali metal nitrite and nitrate salts in an absorption zone at relatively low temperature and pressure to absorb oxygen from the feed air and oxidize the acceptor, removing an oxygen-depleted nitrogen-rich stream from the absorption zone, pumping the oxidized acceptor to an elevated pressure, separately releasing the absorbed oxygen from the acceptor at elevated temperature and the elevated pressure in a desorption zone so as to regenerate the oxygen acceptor and generate high pressure product oxygen and recycling the oxygen acceptor to the absorption zone after reducing its temperature and pressure to absorpation zone conditions.
Claim 2
Dependent Claim
119 words
A continuous process for separating air into oxygen and nitrogen comprising the repeated steps of contacting feed air with an oxygen acceptor mixture of alkali metal nitrite and nitrate salts in an absorption zone at relatively low temperature and pressure to absorb oxygen from the feed air and oxidize the acceptor, removing an oxygen-depleted nitrogen-rich stream from the absorption zone, pumping the oxidized acceptor to an elevated pressure, separately releasing the absorbed oxygen from the acceptor at elevated temperature and the elevated pressure in a desorption zone so as to regenerate the oxygen acceptor and generate high pressure product oxygen and recycling the oxygen acceptor to the absorption zone after reducing its temperature and pressure to absorpation zone conditions.
Claim 3
Dependent Claim
16 words
The process of claim 1 wherein the oxygen-depleted, nitrogen-rich stream constitutes a commercially pure nitrogen product.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein the oxidized acceptor is heat exchanged against the regenerated oxygen acceptor.
Claim 5
Dependent Claim
27 words
The process of claim 1 wherein the change in temperature from the absorption zone to the desorption zone is in the range of 150 to 300° F.
Claim 6
Dependent Claim
27 words
The process of claim 1 wherein the change in pressure from the absorption zone to the desorption zone is in the range of 10 to 50 psia.
Claim 7
Dependent Claim
22 words
The process of claim 1 wherein the change in temperature from the absorption zone to the desorption zone is approximately 250° F.
Claim 8
Dependent Claim
22 words
The process of claim 1 wherein the change in pressure from the absorption zone to the desorption zone is approximately 10 psia.
Claim 9
Dependent Claim
13 words
The process of claim 1 wherein the absorption pressure is approximately 60 psia.
Claim 10
Dependent Claim
13 words
The process of claim 1 wherein the absorption temperature is approximately 950° F.
Claim 11
Dependent Claim
13 words
The process of claim 1 wherein the desorption pressure is approximately 70 psia.
Claim 12
Dependent Claim
13 words
The process of claim 1 wherein the desorption temperature is approximately 1200° F.
References Cited (Backward Citations)
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US4340578A
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US4287170A
Cited
US4421530A
Cited
US4521398A
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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) | 1989-01-20 | 1989-07-22 | 1990-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-20 | 1993-07-22 | 1994-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-20 | 1997-07-22 | 1998-01-21 | $7700.00 | Window Closed / Lapsed |