Process and adsorbent for the recovery of krypton and xenon from a gas or liquid stream
AssigneeAir Products and Chemicals, Inc.
InventorsTimothy Christopher Golden, Thomas Stephen Farris, Robert Ling Chiang, Roger Dean Whitley, Fred William Taylor
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Abstract
Xenon and/or krypton are recovered from oxygen containing gas, typically derived from liquid oxygen bottoms in a cryogenic air separation plant, by selective adsorption on a Li and Ag exchange zeolite containing 5 to 40% Ag exchange capacity on an equivalents basis, with periodic thermal regeneration of the adsorbent.
Claims35
A process for recovering at least one inert gas selected from the group consisting of xenon and krypton from an oxygen-containing gas stream also containing said inert gas comprising selectively adsorbing the inert gas on a solid adsorbent and desorbing and collecting the adsorbed inert gas, wherein the adsorbent is a Li and Ag exchanged X type zeolite.
A process for recovering at least one inert gas selected from the group consisting of krypton and xenon from a liquefied gas stream containing said inert gas and one or more of carbon dioxide, nitrous oxide and hydrocarbon impurities, the process comprising:
- passing the liquefied gas stream in contact with a first adsorbent capable of removing one or more said impurities from the gas stream;
- vaporising the liquefied gas stream to form a gas stream;
- passing the gas stream in contact with a second adsorbent capable of removing said inert gas from the gas stream;
- periodically desorbing krypton and/or xenon from the second adsorbent to form a product gas stream;
- and
- periodically regenerating the first adsorbent, wherein the second adsorbent is a Li and Ag exchanged X-type zeolite.
An apparatus for carrying out a process of adsorption and collection of a component of a feed gas, comprising:
- a first adsorbent bed;
- a second adsorbent bed downstream of the first adsorbent bed;
- an upstream manifold positioned upstream of the first adsorbent bed;
- an intermediate manifold positioned between the first and second adsorbent beds;
- a downstream manifold positioned downstream of the second adsorbent bed;
- a first inlet in the upstream manifold to control the flow of a feed gas across the first and second adsorbent beds;
- a second inlet in the intermediate manifold to control the counter-current flow of a first regeneration gas across the first adsorbent bed only;
- a third inlet in the intermediate manifold to control the co-current flow of a second regeneration gas across the second adsorbent bed only;
- and
- a fourth inlet in the downstream manifold to control the counter-current flow of a desorption gas across the second adsorbent bed only.
An apparatus for carrying out a process for recovering at least one inert gas selected from the group consisting of xenon and krypton from a liquefied feed gas containing said inert gas and one or more impurities selected from carbon dioxide, nitrous oxide and hydrocarbons, said apparatus comprising:
- a first adsorbent bed containing an adsorbent for one or more of said impurities;
- a second adsorbent bed downstream of the first adsorbent bed and containing a Li and Ag exchanged X-type zeolite;
- a mechanism for feeding the liquefied feed gas to the first adsorbent bed;
- a mechanism for vaporising liquefied gas from said first adsorbent bed prior to feeding to said second adsorbent bed;
- and
- a mechanism for feeding a desorption gas to the second adsorbent bed.
Dependencies are inferred from the claim text.