초록 ▼

A pressure swing adsorption process is provided for the direct production from ambient air of a moderately enriched oxygen product gas. The production of a product gas having an oxygen concentration of 23 to 30% is effected by a three step cycle wherein (1) the feed air is charged to a bed of nitrog

A pressure swing adsorption process is provided for the direct production from ambient air of a moderately enriched oxygen product gas. The production of a product gas having an oxygen concentration of 23 to 30% is effected by a three step cycle wherein (1) the feed air is charged to a bed of nitrogen selective adsorbent until the bed is brought from atmospheric pressure to a pressure in the range of up to 10 atmospheres, (2) reducing the bed pressure to an intermediate level by withdrawal of oxygen enriched product gas therefrom and (3) finally venting the bed to restore atmospheric pressure. By an alternative mode including a fourth step of purging the bed following the venting step, a product of 23 to 45% oxygen concentration is obtained.

대표청구항 ▼

The method of obtaining from ambient air a product stream having a moderately enriched oxygen concentration, which comprises the steps of: (1) introducing the feed air into a closed bed of adsorbent selective in retention of nitrogen to increase the pressure in that bed from atmospheric to higher le

The method of obtaining from ambient air a product stream having a moderately enriched oxygen concentration, which comprises the steps of: (1) introducing the feed air into a closed bed of adsorbent selective in retention of nitrogen to increase the pressure in that bed from atmospheric to higher level first pressure of at least 1.5 atmospheres and not in excess of about 10 atmospheres, (2) then immediately upon reaching said first pressure stopping introduction of feed air at the first pressure and reducing the bed pressure from said first pressure to an intermediate level second pressure which is above atmospheric but less than 0.75 times the first pressure by withdrawing from the bed and recovering as product a gas which is enriched in oxygen in the range of 23 to 50% by volume, said withdrawal being carried out in a flow direction concurrent with that of initial introduction of feed air into the bed, (3) and immediately upon reaching said second pressure venting the bed to restore atmospheric pressure therein, said venting being carried out in a flow direction counter to that of said withdrawal of oxygen enriched product gas.