Pressure and temperature swing adsorption and temperature swing

Details Pressure and temperature swing adsorption and temperature swing Pressure and temperature swing adsorption and temperature swing

1997-04-28

1999-09-07

Spitzer, Robert

Gas separation: processes

Solid sorption

Including reduction of pressure

95105, 95106, 95120, 95123, 95143, 96126, 96130, 96144, B01D 53047

Patent

active

059481420

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The present invention relates to methods of treating gases using pressure and temperature swing adsorption, or temperature swing adsorption, together with apparatus and materials for use therein. Particularly the method is directed at purification of gases by removal of particular components therefrom, and the regeneration of adsorbent materials in the apparatus used for the method.
The requirements of an adsorbent system for cyclic filtration processes are not comparable with those of conventional single pass filters. This is because the metallic impregnants on such filters are an undesirable feature as they promote chemisorption. For maximum performance and service life cyclic filtration must therefore proceed reversibly by physical adsorption. Furthermore, the regeneration step must not result in adsorbent degradation; thermal aging, which can result from overheating of the filter bed, being just one example of such adsorbent degradation. In addition to these considerations, other factors such as particle size and hardness must be assessed when selecting adsorbents for PTSA applications.
Air purification processes. such as those required in collective protection situations wherein air from an external source is purified before delivery to an enclosed area occupied by personnel, typically consist of three stages each requiring a different adsorbent material; (i) removal of high boiling contaminants (e.g. boiling point over 50.degree. C.), (ii) removal of water vapour, and (iii) removal of low boiling contaminants (e.g. boiling point below 50.degree. C.). The distinction between high and low boiling contaminants in terms of exact temperature range is not important; the critical requirement is the removal of contaminants having a boiling point between approximately -90.degree. C. and 200.degree. C.).
The identification of an adsorbent for cyclic filtration of high boiling components is especially demanding as such components are generally strongly physically adsorbed and may be irreversibly retained. Adsorbent characterisation using nitrogen adsorption will elucidate the porous characteristics of an adsorbent but are not useful in prediction of adsorption and regeneration properties; adsorption and desorption data for dimethylmethylphosphonate, ethandiol and a range of other high boiling simulants provides more useful data in this regard.
Using such volatile materials the present inventors have studied a variety of adsorbents and determined that, although many of these have high adsorption capacity, in order for a filter bed to be adequately regenerable only certain types of adsorbent materials meet operational requirements.


DETAILED DESCRIPTION OF THE INVENTION

Thus in a first aspect of the present invention there is provided a method for separating one or more volatile contaminants from a subject gas using a temperature, or pressure and temperature, swing adsorbent filtration filter bed apparatus comprising three or more layers of adsorbent materials, characterised in that the layers comprise a first layer of material capable of adsorbing material of relatively high boiling point, a second layer of desiccant material and a third layer of material capable of adsorbing material not adsorbed by the first layer and in that each of the layers may be purged of adsorbed contaminants by a gas having a higher temperature than that from which the contaminants were adsorbed, or having a combination of higher temperature and lower pressure than that from which the contaminants were adsorbed, and the method comprising passing the subject gas through the filters serially in the order first layer, second layer, then third layer.
Although these three are the only layers illustrated in the following examples, the claims should be construed as including the cases where other layers are present, adjacent or between the first, second and third layers described herein.
In a preferred embodiment the layers comprise a first layer of mesoporous adsorbent material a second layer of desiccant mater

REFERENCES:
patent: 2096851 (1937-10-01), Fricke
patent: 2195565 (1940-04-01), Fricke
patent: 2661808 (1953-12-01), Kahle
patent: 2675089 (1954-04-01), Kahle
patent: 3193985 (1965-07-01), Siggelin
patent: 3853516 (1974-12-01), Lyshkow
patent: 3961919 (1976-06-01), Lamoreaux
patent: 4451435 (1984-05-01), Holter et al.
patent: 4544384 (1985-10-01), Metschl et al.
patent: 4572178 (1986-02-01), Takase et al.
patent: 4801313 (1989-01-01), Mann
patent: 4859427 (1989-08-01), Konishi et al.
patent: 4891051 (1990-01-01), Frantz
patent: 5169413 (1992-12-01), Leavitt
patent: 5181942 (1993-01-01), Jain
patent: 5198001 (1993-03-01), Knebel et al.
patent: 5202096 (1993-04-01), Jain
patent: 5221520 (1993-06-01), Cornwell
patent: 5451248 (1995-09-01), Sadkowski et al.
patent: 5674311 (1997-10-01), Notaro et al.

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