Patent ID: 7682422

Claim:
A method for separating and recovering oxygen-rich air from the air, comprising: providing a gas separation membrane module where (i) a laminate comprising a permeate-side spacer for forming a permeate gas channel communicated with a hollow section in a core tube for collecting and discharging a permeate gas and two flat-film gas separation membranes sandwiching the spacer and (ii) a feed-side spacer for forming a feed gas channel are spirally wound around the core tube such that the laminate and the feed-side spacer are alternately superimposed, wherein a thickness ratio of the permeate-side spacer to the feed-side spacer is 1:2 to 1:10; and vacuuming the hollow section of the core tube to 95 kPaA or less by vacuuming means while feeding the air into the feed gas channel by a fan or a blower having such a capacity that a maximum feed-air flow rate and a maximum static pressure divided by an effective membrane area of the gas separation membrane are 100 m 3 /min·m 2 or less and 4000 Pa/m 2 or less, respectively, to separate and recover oxygen-rich air from the hollow section of the core tube.