US 2012/0079939 A1Published application

Recovering of xenon by adsorption process

AssigneeAir Products and Chemicals, Inc.

InventorsAndrew David Johnson, Richard Vincent Pearce, Thomas Stephen Farris, Timothy Christopher Golden, Matthew John Bosco, Eugene Joseph Karwacki, JR., David Charles Winchester, Jeffrey Raymond Hufton

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Abstract

The present invention discloses the improvements to a vacuum swing adsorption (VSA) process used for Xe recovery. By only collecting the recovered gas mixture after the initial evacuation of N2 from the adsorbent vessel and void space, the recovered Xe is not diluted by N2 contained in the adsorbent vessel and void space. The concentration of the recovered Xe can by increased (high purity), simultaneously little Xenon is lost. During the initial evacuation of N2, the vessel has been evacuated to a pressure less than 1 atmospheric pressure, for example, from 100 to 1 torr.

Claims20

Dependent claims

A process of recovering xenon from a Xe-containing feed gas, comprising the steps of:

providing an adsorption vessel containing an adsorbent having a Xe/N2 selectivity ratio of less than 65;
feeding the Xe-containing feed gas into the adsorption vessel, wherein the Xe-containing feed gas comprises an initial concentration of nitrogen greater than 50% and an initial concentration of xenon of at least 0.05%;
evacuating the adsorption vessel by reducing pressure from atmospheric pressure to below atmospheric pressure, wherein the evacuating contains two parts:
(1) evacuating a first part of gas, and (2) recovering a first xenon-enriched gas when the below atmospheric pressure reaches P1;
purging the adsorption vessel when the below atmospheric pressure reaching P2 to recover a second xenon-enriched gas, wherein the purging is maintained at the subatmospheric pressure P2;
and
combining the first xenon-enriched gas and the second xenon-enriched gas to provide a product gas comprising a final concentration of xenon at least 20 times greater than the initial concentration of xenon;
wherein P1 is equal to or greater than P2.

5 more elements

A process of recovering xenon from a Xe-containing feed gas, comprising the steps of:

providing an adsorption vessel containing an adsorbent having a Xe/N2 selectivity ratio of less than 65;
feeding the Xe-containing feed gas into the adsorption vessel, wherein the Xe-containing feed gas comprises an initial concentration of nitrogen greater than 50% and an initial concentration of xenon of at least 0.05%;
evacuating the adsorption vessel by reducing pressure from atmospheric pressure to below atmospheric pressure, wherein the evacuating contains two parts:
(1) recycling a first part of gas into the feeding step, and (2) recovering a first xenon-enriched gas when the below atmospheric pressure reaches P1;
purging the adsorption vessel when the below atmospheric pressure reaching P2 to recover a second xenon-enriched gas, wherein the purging is maintained at the subatmospheric pressure P2;
and
combining the first xenon-enriched gas and the second xenon-enriched gas to provide a product gas comprising a final concentration of xenon at least 20 times greater than the initial concentration of xenon;
wherein P1 is equal to or greater than P2.

5 more elements

Dependencies are inferred from the claim text.