Abstract: The present invention is a method for operating a rapid cycling pressure swing adsorption (RCPSA) having a cycle time, T, to separate a feed gas into a non-adsorbed gas and tail gas. The method includes the steps of passing the feed gas having a purity of F % at high pressure into a first end of a bed which selectively adsorbs the tail gas and passes the product gas out a second end of the bed for a time, F. The product gas has a purity, P %, and a rate of recovery of R %. Then the bed is cocurrently drpressurized for a time, tCO, followed by countercurrently depressurizing the bed for a time, tCN. The bed is then purged for a time, tP, wherein desorbate (tail gas) is released at the first end of the bed at a pressure greater than 30 psig, Subsequently the bed is repressurized for a duration, tRP. R>80%, P/F?1.1 or R?90%, 0<P/F<1.1.