Method and system for pre-purification of a feed gas stream

A method of purifying a feed stream to reduce the hydrogen and carbon monoxide impurities present in the feed stream, the method comprising the steps of:

• (a) passing the feed stream through at least one layer of adsorbent configured to remove water and carbon dioxide from the feed stream and yield a dry feed stream substantially free of water and carbon dioxide;
• (b) passing the dry feed stream through a first layer of manganese oxide and copper oxide containing catalyst configured to remove at least some of the carbon monoxide and hydrogen from the dry feed stream and produce a first intermediate effluent stream;
• (c) passing the first intermediate effluent stream through a first intermediate layer disposed downstream of the first layer of manganese oxide and copper oxide containing catalyst, the first intermediate layer configured to remove at least carbon dioxide from the first intermediate effluent stream and produce a second intermediate effluent stream;
• and
• (d) passing the second intermediate effluent stream through a second layer of manganese oxide and copper oxide containing catalyst disposed downstream of the first intermediate layer and configured to remove at least hydrogen from the second intermediate effluent stream to yield third intermediate effluent stream;
• wherein the first intermediate layer comprises a molecular sieve layer or a layer of alumina.