Patent US3856928A successfully refreshed from Google Patents.
US3856928A
Expired / Lapsed
US
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Oxygen production process
Assignee: Consolidated Natural Gas Service Co Inc
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Filing: 1972-06-07
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Granted: 1974-12-24
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Expires: 1992-06-07
Abstract
Abstract Process and apparatus for the production of oxygen or enriched air employing a packed bed of an oxygen-accepting solid, e.g. a barium oxide with MgO and CaO, for example BaO2-DQL. The process is substantially adiabatic with respect to the bed, and is characterized by 4-step cyclic operation: Pressurization, oxidation, depressurization, and reduction. The pressure during the oxidation portion of the cycle ranges from 14 - 385 psia, and during reduction from 1 - 45 psia, wherein the ratio of pressure during oxidation to that during reduction is between 1.6 and 15. The half-cycle time, that is the time the reactor is maintained in either oxidizing or reducing mode ranges from 30 seconds to 360 seconds, and the space velocity ranges from 200 - 5,000 SCF/cu. ft. bed-hour. The bed may be operated either cocurrently or counter-currently in either an upflow or downflow mode, and the process temperature may range from 1250* - 1600*F. The air used in the process is dried and rendered CO2-free by conventional means.
Inventors
- 👤 P Tarman
- 👤 L Massey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 07:52
CPC Classifications
C; C01; C01B; C01B13/00; C01B13/02; C01B13/0229; C01B13/0248; C01B13/0259; C01B13/0262; C01B13/0203; C01B13/0211; C01B2210/00; C01B2210/0043; C01B2210/0046; C01B2210/0051; C01B2210/0062
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
283 words
IN A PROCESS FOR PRODUCING OXYGEN OR ENRICHMENT OF AIR BY INCREASING ITS OXYGEN CONTENT WHICH INVLUDES THE STEPS OF COMPRESSING AND HEATING AIR TO ELEVATED PRESSURE AND TEMPERATURE, PASSING SAID AIR INTO CONTACT WITH A BED CONTAINING AN OXYGEN ACCEPTOR COMPOUND TO OXIDIZE SAID COMPOUND IN A REDUCOXIDATION HALF CYCLE, AND REDUCING THE PRESSURE OVER SAID COMPOUND TO EFFECT REDUCTION OF SAID COMPOUND IN A REDUCTION HALF CYCLE AND RECOVERING AN OXYGEN-CONTAINING GAS THEREFROM. THE IMPROVEMENT WHEREIN: A. SAID BED COMPOUND IS AN ACTIVE COMPOSITION OF A BARIUM OXIDE WITH MGO AND CAO, . SAID BED IS MAINTAINED AT A TEMPERATURE OF FROM ABOUT 1,250*F TO ABOUT 1,600*F, C. THE PRESSURE OF AIR OVER SAID BED DURING SAID OXIDATION IS MAINTAINED IN A RANGE OF FROM ABOUT 14 TO ABOUT 385 PSIA, D. THE PRESSURE OVER SAID BED DURING REDUCTION OF SAID BED IS MAINTAINED IN A RANGE OF FROM ABOUT 14 TO ABOUT 385 PSIA, E. THE RATIO OF SAID OXIDATION PRESSURE TO SAID REDUCTION PRESSURE IS MAINTAINED IN A RANGE OF FROM ABOUT 1.6 TO ABOUT 15, F. SAID HALF CYCLES OF REDUCTION OR OXIDATION, EXCLUSIVE OF PRESSURIZATION OF DEPRESSURIZATION, ARE MAINTAINED FOR A TIME OF FROM ABOUT 30 TO ABOUT 360 SECONDS, G. SAID PASSING OF SAID AIR THROUGH SAID BED DURING OXIDATION IS MAINTAINED AT A SPACE VELOCITY OF FROM ABOUT 200 TO ABOUT 5,000 SCF/CU. FT. BED-HR, H. A LEAN GAS IS WITHDRAWN FROM SAID BED DURING OXIDATION HAVING AN OXYGEN CONCENTRATION OF FROM ABOUT 5 TO ABOUT 15 MOLE PERCENT, AND I. AT LEAST ONE FRACTION OF PRODUCT GAS IS WITHDRAWN FROM SAID BED DURING REDUCTION HAVING AN OXYGEN CONCENTRATION OF ABOVE ABOUT 22 MOLE PERCENT.
Claim 2
Dependent Claim
283 words
IN A PROCESS FOR PRODUCING OXYGEN OR ENRICHMENT OF AIR BY INCREASING ITS OXYGEN CONTENT WHICH INVLUDES THE STEPS OF COMPRESSING AND HEATING AIR TO ELEVATED PRESSURE AND TEMPERATURE, PASSING SAID AIR INTO CONTACT WITH A BED CONTAINING AN OXYGEN ACCEPTOR COMPOUND TO OXIDIZE SAID COMPOUND IN A REDUCOXIDATION HALF CYCLE, AND REDUCING THE PRESSURE OVER SAID COMPOUND TO EFFECT REDUCTION OF SAID COMPOUND IN A REDUCTION HALF CYCLE AND RECOVERING AN OXYGEN-CONTAINING GAS THEREFROM. THE IMPROVEMENT WHEREIN: A. SAID BED COMPOUND IS AN ACTIVE COMPOSITION OF A BARIUM OXIDE WITH MGO AND CAO, . SAID BED IS MAINTAINED AT A TEMPERATURE OF FROM ABOUT 1,250*F TO ABOUT 1,600*F, C. THE PRESSURE OF AIR OVER SAID BED DURING SAID OXIDATION IS MAINTAINED IN A RANGE OF FROM ABOUT 14 TO ABOUT 385 PSIA, D. THE PRESSURE OVER SAID BED DURING REDUCTION OF SAID BED IS MAINTAINED IN A RANGE OF FROM ABOUT 14 TO ABOUT 385 PSIA, E. THE RATIO OF SAID OXIDATION PRESSURE TO SAID REDUCTION PRESSURE IS MAINTAINED IN A RANGE OF FROM ABOUT 1.6 TO ABOUT 15, F. SAID HALF CYCLES OF REDUCTION OR OXIDATION, EXCLUSIVE OF PRESSURIZATION OF DEPRESSURIZATION, ARE MAINTAINED FOR A TIME OF FROM ABOUT 30 TO ABOUT 360 SECONDS, G. SAID PASSING OF SAID AIR THROUGH SAID BED DURING OXIDATION IS MAINTAINED AT A SPACE VELOCITY OF FROM ABOUT 200 TO ABOUT 5,000 SCF/CU. FT. BED-HR, H. A LEAN GAS IS WITHDRAWN FROM SAID BED DURING OXIDATION HAVING AN OXYGEN CONCENTRATION OF FROM ABOUT 5 TO ABOUT 15 MOLE PERCENT, AND I. AT LEAST ONE FRACTION OF PRODUCT GAS IS WITHDRAWN FROM SAID BED DURING REDUCTION HAVING AN OXYGEN CONCENTRATION OF ABOVE ABOUT 22 MOLE PERCENT.
Claim 3
Dependent Claim
21 words
The process as in claim 1 wherein said oxygen acceptor bed material is an active composition of BaO2 with Dolomitic Quicklime.
Claim 4
Dependent Claim
113 words
The process as in claim 2 wherein: a. said bed temperature is from about 1,350* to about 1,500*F, b. said oxidation pressure is from about 21 to about 150 psia, c. said ratio of oxidation pressure to reduction pressure ranges from about 2.5 to about 8.0, d. said half cycle time is from about 60 to about 180 seconds, e. said space velocity is from about 700 to about 2,000 SCF (cu. ft. bed-hr.) 1, f. said pressure over said bed during reduction is from about 7 to about 45 psia, and g. said product gas is an enriched air having an oxygen concentration of from about 25 to about 75 mole percent.
Claim 5
Dependent Claim
39 words
The process as in claim 1 which includes the added step of passing said compressed air into contact with a bed of barium monoxide to guard said bed oxygen acceptor compound from excess concentrations of water vapor and CO2.
Claim 6
Dependent Claim
28 words
The process as in claim 1 which includes steps of pressurizing said bed prior to oxidation and depressurizing said bed between said half cycles of oxidation and reduction.
Claim 7
Dependent Claim
77 words
The process as in claim 1 which includes a repetitive sequence of four steps per cycle in the order of reduction, pressurization, oxidation and depressurization, said bed material is disposed in a plurality of reactors some of which are operating in different steps of said cycle with respect to each other, and which includes the step of controlling the flow of gases into and out of said reactors to maintain a substantially uniform output of product gas.
Claim 8
Dependent Claim
34 words
The process as in claim 6 wherein a portion of the depressurizing gas exiting from a first reactor is passed into a second reactor to assist in the pressurizing step of said second reactor.
Claim 9
Dependent Claim
32 words
The process as in claim 1 wherein said step of withdrawing gases from said bed during reduction includes use of a compressor downstream of said bed to pull gases from said bed.
Claim 10
Dependent Claim
29 words
The process as in claim 1 wherein said step of withdrawing product gas includes passing air through said bed during reduction to enrich the oxygen content of said air.
Claim 11
Dependent Claim
26 words
The process as in claim 1 wherein the pressure over said bed during reduction is subatmospheric and a fraction of substantially pure oxygen is removed therefrom.
Claim 12
Dependent Claim
26 words
The process as in claim 1 which includes the added step of recovering energy from said lean gas by passing it through an expander or turbine.
Claim 13
Dependent Claim
19 words
The process as in claim 11 wherein said energy recovery step includes burning a fuel with said lean gas.
Claim 14
Dependent Claim
35 words
The process as in claim 12 wherein said energy recovery step includes bypassing a portion of said compressed air to said lean air stream and burning said fuel with said air and said lean air.
Claim 15
Dependent Claim
21 words
The process as in claim 1 wherein said step of withdrawing product gas includes withdrawing said gas at an elevated temperature.
Claim 16
Dependent Claim
53 words
The process as in claim 14 wherein said step of withdrawing product gas at an elevated temperature includes passing air through said bed during reduction to enrich the oxygen content of said air, and passing said reduction air into heat exchange relationship with said lean gas, or a portion of said product gas.
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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |