US 4,801,308 AGranted

Apparatus and process for pressure swing adsorption separation

OwnerBowie G. Keeferinventor

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Abstract

Pressure swing adsorption separation of a gas mixture containing a more readily adsorbed component and a less readily adsorbed component is performed within an apparatus containing an adsorbent bed with cyclically varied geometry, such that the bed volume can be expanded or contracted. Variable volume displacement means at either end of a flow path through the adsorbent bed are operated cyclically to generate flow of a gas mixture along the flow path, in a first direction when the more readily adsorbed component is preferentially adsorbed during the high pressure portion of the cycle while the bed volume is relatively contracted, and in a second reverse direction during the low pressure portion of the cycle while the bed volume is relatively expanded. The apparatus separates the gas mixture and also converts thermal energy by a thermodynamic cycle, such that heat and the more readily adsorbed component are transported in the second direction, while the less readily adsorbed component is transported in the first direction. Adsorbent bed volume is contracted while pressure is rising, and expanded while pressure is reducing, thus minimizing flow along the flow path except when the more readily adsorbed component is maximally or minimally adsorbed, and consequently improving performance of the pressure swing adsorption cycle.

Claims41

Dependent claims

A process for separating components of a gas mixture containing a first component which is more readily adsorbed and a second component which is less readily adsorbed by an adsorbent material, the process including the steps of;

(a) introducing the gas mixture into a flow path having first and second ends and an adsorbent bed containing the adsorbent material and providing a flow path volume associated with the flow path and including volume of flow channels of the adsorbent bed, the flow path being disposed between first and second cyclic flow generation means at opposite ends of the adsorbent bed
(b) cyclically imposing a flow of the gas mixture in the flow path so as to have cyclic reversals of flow direction along the flow path at a periodic frequency,
(c) cyclically exchanging heat between the gas mixture in the flow path and a material with heat capacity disposed along the flow path,
(d) cyclically varying total pressure of the gas mixture in the flow path between upper and lower limits, at the same periodic frequency and with phase coordinated with the cyclic reversals of the flow direction,
(e) preferentially adsorbing the first component on the adsorbent material under increased pressure when the gas mixture is flowing along the flow path in the direction toward the second end of the adsorbent bed, and desorbing the first component so that it is free to move with the flow under decreased pressure and the flow direction is reversed toward the first end of the adsorbent bed,
(f) separating the gas mixture in the flow path by enriching flow toward the first end of the bed in the first component, and enriching flow toward the second end of the bed in the second component,
(g) cyclically varying the flow path volume between minimum and maximum limits in accordance with the cyclic pressure variations, so the flow path volume is reduced toward the minimum limit thereof when pressure is higher, and the flow path volume is increased toward the maximum limit thereof when the pressure is lower.

4 more elements

A process for separating components of a gas mixture, the process including the steps of:

(a) providing a gas mixture containing a first component which is more rapidly adsorbed by an adsorbent material under increase of pressure than a second component of the gas mixture, so that the selectivity of the adsorbed between the first and second components is substantially based on preferential rate of sorption,
(b) introducing the gas mixture into a flow path through an adsorbent bed containing the adsorbent material,
(c) connecting a first end of the adsorbent bed to a first volume displacement means maintained approximately at a first temperature, and connecting a second end of the adsorbent bed to a second volume displacement means maintained approximately at a second temperature,
(d) cyclically varying the volume of the flow path by displacing the first and second volume displacement means, at equal frequencies and with a leading phase of volume changes generated by the second volume displacement means relative to volume changes generated by the first volume displacement means, thus imposing cyclically reversing flow in the flow path and cyclic variations of pressure in the adsorbent bed,
(e) preferentially adsorbing the first component under increased pressure when the flow is directed toward the second volume displacement means and the flow is then enriched in the second component,
(f) followed by preferentially desorbing the first component under reduced pressure when the flow is directed toward the first volume displacement means and the flow is then enriched in the first component,
(g) separating the first component toward the first volume displacement means, and separating the second component toward the second volume displacement means,
(h) withdrawing gas enriched in the first component from adjacent the first volume displacement means, and withdrawing gas enriched in the second component from adjacent the second volume displacement means,
(i) over each complete cycle, delivering net heat of compression from adjacent the first volume displacement means and taking up net heat of expansion adjacent the second volume displacement means.

6 more elements

An apparatus for pressure swing adsorption separation between first and second gas components of a gas mixture, the first component being more readily adsorbed than the second component by an adsorbent material under increase of pressure, the apparatus including:

(a) an adsorbent bed having first and second ends and containing the adsorbent material disposed along a flow path, the adsorbent bed having a variable flow path volume associated with the flow path and means for varying cyclically the flow path volume of the adsorbent bed,
(b) first and second flow generation means ommunicating with first and second ends respectively of the adsorbent bed,
(c) means to cyclically operate the first and second flow generation means at equal periodic frequencies, and with different phase to impose flow of the gas mixture in the flow path with cyclic reversals of flow direction along the flow path, while also cyclically varying the total pressure in the flow path in the same frequency, so that the pressure is relatively high when the flow in the flow path is directed toward the second flow generation means, and the pressure is relatively low when the flow in the flow path is directed toward the first flow generation means,
(d) for coordinating the cyclical variations of the flow path volume of the adsorbent bed with the cyclic operation of the first and second flow generation means,

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 06/929,438Filed 12 Nov 1986 · continuation in part
Priority: 3 Oct 1983
Granted: 31 Jan 1989
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

B01D 53/0407
With stationary adsorbents: constructional details of adsorbing systems
B01D 53/04
By adsorption, e.g. preparative gas chromatography: with stationary adsorbents
B01D 53/0423
Constructional details of adsorbing systems: beds in columns
F02G 1/0435
The engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly…:…