Adsorption Equilibria and Performance of a Pressure Swing Adsorption Air Separation Unit

摘要

Current pressure swing adsorption (PSA) air separation units operating on short cycle times suffer a reduction in product oxygen concentration when subjected to lower ambient temperatures (i.e., less than -10 C. This work investigates this problem based on analysis of adsorption equilibria, column breakthrough studies, and actual PSA system data. Pure and multicomponent data for nitrogen, oxygen, and air on molecular sieve 5A were collected at 24, -40, and -70 C up to pressures of 4.3 atmospheres absolute. Using a statistical thermodynamic model pure component data were adequately predicted over the entire temperature range (24 to -70 C). The multicomponent data were predicted at 24 C by a statistical thermodynamic model and ideal adsorbed solution theory. At the lower temperatures the gas mixture behaved nonideally.