Single bed pressure swing adsorption system and process

Claim 1

An improved pressure swing adsorption process for the recovery of oxygen from air, comprising: (a) passing feed air to a feed end of a single bed of adsorbent material capable of selectively adsorbing nitrogen, as the more adsorbable component of air, the pressure in the bed increasing from an intermediate pressure to an upper adsorption pressure, with oxygen, as the less adsorbable component of air, passing from a product end of the bed to a product surge tank at pressure approaching said upper adsorption pressure; (b) cocurrently depressurizing the bed to said intermediate pressure with the release of void space gas from the product end of the bed, said void space gas passing to an equalization tank; (c) countercurrently depressurizing the bed from said intermediate pressure to a lower desorption pressure, with the release of additional quantities of gas from the feed end of the bed; (d) passing a side stream of product gas from the product surge tank to the product end of the bed as purge gas to displace desorbed nitrogen from the void volume in the bed at the lower desorption pressure, the displaced desorbed nitrogen being discharged from the feed end of the bed; and (e) introducing void space gas from said equalization tank to the product end of the bed to increase the pressure in the bed from the lower desorption pressure to said intermediate pressure; and (f) passing additional quantities of feed air to the feed end of said single bed as cyclic operation of (a)-(e) above is continued, whereby product oxygen is recovered from air at the enhanced product flow rate, with the adsorptive capacity of the single bed of adsorbed material likewise being enhanced.