A new compact design of pressure swing adsorption (PSA) equipment was presented. All columns of the PSA process reduced to disks that are stacked tightly together. The total size of the equipment was thus substantially reduced. The feasibility and the process performance of the new design were tested with a four-bed process aiming to produce oxygen from air. The adsorbent used was zeolite molecular sieve ZMS-5A. Although the process performance was limited by the relatively nonefficient adsorbent, the feasibility of the compact arrangement of disk columns was proven, and the advantages in the compensation of the thermal effect of adsorption and in the higher energy efficiency were also demonstrated. (c) 2005 American Institute of Chemical Engineers.