Pressure swing adsorption process for the separation of a feed gas mixture comprising (a) providing a pressure swing adsorption system comprising one or more composite beds, each composite bed comprising adsorbent material disposed in two or more vessels in parallel flow configuration, each vessel having a feed end and a product end; (b) performing cyclic sequential steps comprising adsorption/make product, withdrawing gas at decreasing pressure from the composite bed, purging the composite bed, and introducing gas into the composite bed at increasing pressure; and (c) for any of the sequential steps, setting a flow rate or flow rates of one or more gases selected from the group consisting of gas introduced into or withdrawn from the feed end or ends of any of the two or more vessels and gas introduced into or withdrawn from the product end or ends of any of the two or more vessels.