METHOD FOR CONCURRENT SEPARATION OF OXYGEN GAS AND NITROGEN GAS, AND SYSTEM FOR THE CONCURRENT SEPARATION

摘要

A method for concurrently separating oxygen and nitrogen comprising the PSA gas separation step which is performed in a PSA gas separation apparatus (1) and the membrane gas separation step which is performed in a membrane gas separator (2). In the PSA gas separation step, an oxygen-rich gas is removed from a gas containing both oxygen and nitrogen (e.g., air) by a pressure-changeable adsorption gas separation method which is performed using an adsorption column filled with an adsorbent which can adsorb nitrogen preferentially and, at the same time, a desorbed gas which contains mainly nitrogen but also contains oxygen is removed. In the membrane gas separation step, a desorbed gas supplied from the PSA gas separation apparatus (1) is fractionated into a gas which can pass through a gas separation membrane (2A) and a gas which cannot (a nitrogen-rich gas), while introducing a portion of the desorbed gas into a gas separation membrane (2A)-passed fraction without making pass through the gas separation membrane (2A).