Process for separating a feed stream gas mixture using pressure swing adsorption

Claim 1

A molecular sieve, pressure swing adsorption process employing two adsorbers for generating enriched gas from a feed stream gas mixture, wherein a first of said two adsorbers repeatedly passes through sequential steps comprising: (a) cocurrently passing said feed stream gas mixture through said first of two adsorbers at an adsorption pressure greater than atmospheric pressure, thereby producing an enriched product gas; (b) cocurrently partially depressurizing said first adsorber by venting it to the second of said two adsorbers until the pressures of said first and second adsorbers are equalized; thereby simultaneously partially repressurizing said second adsorber; (c) countercurrently depressurizing said first adsorber to atmosphere, thereby reducing the pressure of said first adsorber to atmospheric pressure; (d) regenerating said first adsorber by purging said first adsorber with enriched product gas, thereby causing adsorbate in the pores of said molecular sieve adsorber to be desorbed; (e) partially repressurizing said first adsorber by adding enriched product gas to said first adsorber; (f) cocurrently partially repressurizing said first adsorber by cocurrently venting said second adsorber to said first adsorber until the pressures of said first and second adsorbers are equalized, thereby simultaneously partially depressurizing said second adsorber; and (g) repressurizing said first adsorber to said adsorption pressure using said feed stream gas mixture; and wherein said second of said two adsorbers repeatedly passes through Steps(a) through (g) above, treating the second adsorber as the first adsorber and vice versa, and wherein the operating sequences for said first adsorber and said second adsorber align so that Step (a) for said first adsorber occurs simultaneously with Step (g) for said-second adsorber and Step (a) for said second adsorber occurs simultaneous with Step (g) for said first adsorber.