Patent ID: 8343259
Filing Date: 2013-01-01
Classification: B01D

Abstract:
1. In a method for subjecting feed air to fractionation for recovery of a product oxygen fraction therefrom in a pressure swing adsorption (PSA) process utilizing a nitrogen-selective adsorbent (“NSA”) that is sensitive to moisture, said PSA process including the steps of feed pressurization, production, equalization, and blowdown, the improvement which comprises the steps of: (a) placing a bed of pre-treatment adsorbent between feed air and a bed of NSA; (b) interposing a controllable valve between said pre-treatment adsorbent bed and said NSA bed; (c) locating an output controllable valve at the output of said NSA bed; and (d) keeping said output controllable valve open and said interposed controllable valve closed during the steps of production, equalization, and when the process is idle, production occurring only when said output controllable valve is open and said interposed controllable valve is closed, said output controllable valve being open only during production and not being open during feed pressurization, equalization, or blowdown.