PSA process with dynamic purge control

Claim 1

A cyclic PSA process for recovering first component-enriched gas from a gas mixture containing first and second components in a system comprised of a battery of two or more beds of adsorbent which more strongly adsorb the second component than the first component, said beds being arranged in parallel and operated out of phase such that at least one bed is in adsorption service while at least one other bed is being regenerated, wherein a specific event occurs during each period of bed regeneration, comprising the following steps: (a) flowing said gas mixture into said at least one bed, thereby pressurizing said at least one bed to a selected adsorption pressure and producing first component-enriched gas as a nonadsorbed product, while regenerating said at least one other bed by desorbing second component-enriched gas therefrom at a selected vent pressure, said at least one other bed being purged with first component-enriched gas during at least part of the period of regeneration of said at least one other bed; (b) repeating step (a) with the roles of said at least one bed and said at least one other bed being changed until all beds of said system have undergone step (a); (c) periodically determining the absolute difference between the concentration of first component in the second component-enriched gas being desorbed from said at least one other bed upon the occurrence of said specific event during a period of regeneration of said at least one other bed and the concentration of first component in the second component-enriched gas being desorbed from said at least one bed upon the occurrence of said specific event during a period of regeneration of said at least one bed, and (d) periodically adjusting the duration of purge in one or more of said at least one bed and said at least one other bed in a manner that will reduce said absolute difference.