Patent ID: 7294172

Claim:
A gas recovery system comprising a source of gas having a preselected concentration of a desired component, at least one application that adds impurities to said gas, and at least one adsorption system that purifies said gas to produce a purified gas for re-use in said application, wherein said at least one adsorption system includes at least one adsorbent bed (A) having at least three layers of adsorbents, and wherein a waste stream generated by the at least one adsorption system can be selectively recycled to the same at least one adsorption system until a predetermined upper limit of waste impurities in said waste stream is reached; and wherein said waste stream can be treated prior to recycle to said same at least one adsorption system when said waste impurities are above said predetermined upper limit such that waste impurities in said waste stream can be removed until a level below said predetermined upper limit is reached.