US4842621A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery process
Assignee: Dow Chemical Co
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Filing: 1987-03-26
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Granted: 1989-06-27
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Expires: 2007-03-26
Abstract
Abstract The present invention provides a process for separating a condensable gas from a non-condensable gas by switching at least three adsorber beds which preferentially adsorb the condensable gas serially through the following steps: (a) an adsorption step in which a mixture of the condensable and non-condensable gases are passed through the bed and the separated non-condensable gas is withdrawn therefrom; (b) a supercharging step in which a stream relatively rich in the condensable gas is passed through the bed, the stream having an actual volume at least three times that necessary to displace a void volume of the bed; (c) a desorption step in which a vacuum is drawn on the bed and an amount of a non-condensable gas is bled through the bed; and wherein the non-condensable gas in conjunction with entrained condensable gas from step (c) is passed into a vacuum pump, is compressed, at least some of the condensable gas is condensed and at least part of the non-condensable gas and remaining condensable gas is the passed to step (b) as the stream relatively rich in the condensable gas; and such that continuous operation of the process with at least one of the beds in the adsorption step is permitted. In an example 1,1,1-trichloroethane is separated from air.
Inventors
- 👤 Lanny A. Robbins
- 👤 Herbert A. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:26
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/02; B01D53/04; B01D53/047; B01D53/0476; B01D2253/00; B01D2253/10; B01D2253/102; B01D2253/30; B01D2253/302; B01D2253/304; B01D2257/00; B01D2257/20; B01D2257/206; B01D2257/2064; B01D2259/00; B01D2259/40; B01D2259/40007; B01D2259/40009; B01D2259/40011; B01D2259/4002; B01D2259/40022; B01D2259/40058; B01D2259/4006; B01D2259/40062; B01D2259/403
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
218 words
A process for separating a condensable gas from a non-condensable gas comprising switching at least three adsorber beds which preferentially adsorb the condensable gas serially through the following steps: (a) an adsorption step in which a mixture of the condensable and non-condensable gases are passed through the bed and the separated non-condensable gas is withdrawn therefrom; (b) a supercharging step in which a stream relatively rich in the condensable gas is passed through the bed, said stream having an actual volume at least three times that necessary to displace a void volume of the bed and wherein a pressure in the bed undergoing step (b) is elevated over that in the bed undergoing step (a); (c) a desorption step in which a vacuum is drawn on the bed and an amount of non-condensable gas is bled through the bed; and wherein said non-consensable gas in conjunction with entrained condensable gas from step (c) is passed into a vacuum pump, is compressed, at least some of the condensable gas is condensed and at least part of the non-condensable gas and remaining condensable gas is then passed to step (b) as the stream relatively rich in the condensable gas; and such that continuous operation of the process with at least one of the beds in the adsorption step is permitted.
Claim 2
Dependent Claim
218 words
A process for separating a condensable gas from a non-condensable gas comprising switching at least three adsorber beds which preferentially adsorb the condensable gas serially through the following steps: (a) an adsorption step in which a mixture of the condensable and non-condensable gases are passed through the bed and the separated non-condensable gas is withdrawn therefrom; (b) a supercharging step in which a stream relatively rich in the condensable gas is passed through the bed, said stream having an actual volume at least three times that necessary to displace a void volume of the bed and wherein a pressure in the bed undergoing step (b) is elevated over that in the bed undergoing step (a); (c) a desorption step in which a vacuum is drawn on the bed and an amount of non-condensable gas is bled through the bed; and wherein said non-consensable gas in conjunction with entrained condensable gas from step (c) is passed into a vacuum pump, is compressed, at least some of the condensable gas is condensed and at least part of the non-condensable gas and remaining condensable gas is then passed to step (b) as the stream relatively rich in the condensable gas; and such that continuous operation of the process with at least one of the beds in the adsorption step is permitted.
Claim 3
Dependent Claim
42 words
The process of claim 1 wherein the adsorber beds are additionally passed serially through a fourth step comprising: (d) a repressurization step in which the pressure in the bed is raised to about the pressure of step (a) with clean non-condensable gas.
Claim 4
Dependent Claim
22 words
The process of claim 1 wherein a pressure in the bed undergoing step (a) is from about 12 to about 16 psia.
Claim 5
Dependent Claim
22 words
The process of claim 1 wherein a pressure in the bed undergoing step (b) is from about 16 to about 25 psia.
Claim 6
Dependent Claim
22 words
The process of claim 1 wherein a pressure in the bed undergoing step (c) is from about 50 to about 350 torr.
Claim 7
Dependent Claim
40 words
The process of claim 1 wherein a pressure in the bed undergoing step (c) is about the vapor pressure of the condensable gas at the temperature of operation of a vacuum pump which is drawing the vacuum of step (c).
Claim 8
Dependent Claim
20 words
The process of claim 1 wherein a liquid ring vacuum pump is used to draw the vacuum of step (c).
Claim 9
Dependent Claim
13 words
The process of claim 1 wherein the condensable gas is a chlorinated hydrocarbon.
Claim 10
Dependent Claim
11 words
The process of claim 1 wherein the condensable gas is 1,1,1-trichloroethane.
Claim 11
Dependent Claim
11 words
The process of claim 1 wherein the non-condensable gas is air.
References Cited (Backward Citations)
US2910137A
Cited
US3089250A
Cited
US3085379A
Cited
US3477206A
Cited
US3717974A
Cited
US3948622A
Cited
US4013429A
Cited
US4104039A
Cited
US4056369A
Cited
US4066423A
Cited
US4077779A
Cited
US4077780A
Cited
US4171206A
Cited
US4171207A
Cited
US4261716A
Cited
US4331456A
Cited
US4305734A
Cited
US4515605A
Cited
US4359328A
Cited
US4421532A
Cited
US4276058A
Cited
US4343629A
Cited
US4338101A
Cited
US4376640A
Cited
US4528000A
Cited
US4462811A
Cited
US4599094A
Cited
US4670028A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-26 | 1992-12-26 | 1993-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-26 | 1996-12-26 | 1997-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-26 | 2000-12-26 | 2001-06-27 | $7700.00 | Window Closed / Lapsed |