Oxygen enrichment process

Claim 1

In a method for regenerating adsorbents reduced in sorbent capacity during use in an oxygen enrichment vacuum swing gas separation and purification system utilizing a first bed of absorbent effective in adsorption of carbon dioxide and water and a second bed of adsorbent selective in retention of nitrogen as opposed to oxygen, said system operating on a cycle including a sorbtive gas separation and purification period and a regeneration period during which charge gas flow is discontinued, the improvement in regeneration which comprises, a. applying a vacuum to the inlet end of said first bed while maintaining flow communication between said first bed and said second bed, b. continuing application of said vacuum to said beds and attaining a reduced intermediate pressure of less than 60 mm. Hg, thereby desorbing gases from said beds including substantially all of the nitrogen from said second bed, c. discontinuing flow communication between said second and said first beds while continuing vacuum application to said first bed to a lower terminal pressure at least 10mm. Hg below said intermediate pressure thereby desorbing any residual moisture and carbon dioxide from said first bed, d. repressuring said second bed with product gas to about sorption cycle pressure during said continuing vacuum application to said first bed, e. discontinuing vacuum application to said first bed and repressuring said first bed to about sorptive cycle pressure, f. re-establishing flow communication between said first bed and said second bed and resuming the charge gas flow for sorbtive gas separation and purification.