US4526775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles
Assignee: Air Products and Chemicals Inc
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Filing: 1984-02-23
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Granted: 1985-07-02
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Expires: 2004-02-23
Abstract
Abstract A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs.
Inventors
- 👤 Anthony A. Cassano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:21
CPC Classifications
C; C01; C01B; C01B13/00; C01B13/02; B; B01; B01D; B01D53/00; B01D53/14; B01D53/1493; B01D53/1406; C01B13/0292
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
109 words
In a continuous chemical process for separating air into oxygen and nitrogen in which pressurized air is contacted in an absorption zone with an oxygen acceptor which becomes oxidized. the oxidized oxygen acceptor is separately decomposed by pressure reduction and/or supplying heat in a desorption zone to yield an oxygen product and regenerated oxygen acceptor and the regenerated oxygen acceptor is recycled to the absorption zone characterized in that the pressurized air is separated using the oxygen acceptor in a plurality of staged absorption zones in which each staged zone is connected to a separate desorption zone for the recovery of oxygen product and the regeneration of oxygen acceptor.
Claim 2
Dependent Claim
109 words
In a continuous chemical process for separating air into oxygen and nitrogen in which pressurized air is contacted in an absorption zone with an oxygen acceptor which becomes oxidized. the oxidized oxygen acceptor is separately decomposed by pressure reduction and/or supplying heat in a desorption zone to yield an oxygen product and regenerated oxygen acceptor and the regenerated oxygen acceptor is recycled to the absorption zone characterized in that the pressurized air is separated using the oxygen acceptor in a plurality of staged absorption zones in which each staged zone is connected to a separate desorption zone for the recovery of oxygen product and the regeneration of oxygen acceptor.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the separation is performed in two absorption zones with attendant desorption zones.
Claim 4
Dependent Claim
40 words
The process of claim 2 wherein the first absorption zone has an attendant desorption zone comprising two desorption stages contacted in series in order to recover relatively high pressure oxygen product and relatively intermediate pressure oxygen from the desorption zone.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein a commercially pure nitrogen product is recovered from the final absorption zone.
Claim 6
Dependent Claim
21 words
The process of claim 1 wherein the oxygen acceptor comprises a molten solution of alkali metal nitrite and alkali metal nitrate.
Claim 7
Dependent Claim
19 words
The process of claim 1 wherein the separation is performed in three absorption zones with attendant separate desorption zones.
Claim 8
Dependent Claim
21 words
The process of claim 6 wherein oxygen product is recovered at a high pressure, an intermediate pressure and a low pressure.
Claim 9
Dependent Claim
33 words
The process of claim 7 wherein the high pressure oxygen is at approximately 15 psia, the intermediate pressure is at approximately 6 psia and the low pressure oxygen is at approximately 2.5 psia.
Claim 10
Dependent Claim
37 words
The process of claim 7 wherein approximately 25% of the oxygen is recovered at high pressure, approximately 52% of the oxygen is recovered at intermediate pressure and approximately 13% of the oxygen is recovered at low pressure.
Claim 11
Dependent Claim
28 words
The process of claim 1 wherein the oxygen product recovered from each desorption zone is commercially pure oxygen having a purity of at least 99.5% O 2 .
Claim 12
Dependent Claim
30 words
The process of claim 5 wherein the anion composition includes 50-94% nitrate, 4-25% nitrite and 0.5-25% peroxides and superoxides and the cation composition includes 30-70% sodium with the balance potassium.
References Cited (Backward Citations)
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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) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |