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

A pre-purification unit configured for use with an air-separation unit, the pre-purification unit comprising:

• a pre-purification vessel having an inlet configured to receive a stream of feed air and an outlet configured to direct a purified stream substantially free of water, carbon dioxide, carbon monoxide and hydrogen;
• a first hopcalite catalyst layer configured to remove carbon monoxide and hydrogen from the stream of feed air and produce a first intermediate effluent substantially free of carbon monoxide;
• an adsorbent layer disposed downstream of the first hopcalite catalyst layer, the adsorbent layer configured to remove at least carbon dioxide from the first intermediate effluent and produce a second intermediate effluent substantially free of carbon dioxide;
• and
• a second hopcalite catalyst layer disposed downstream of the adsorbent layer, the second hopcalite catalyst layer configured to remove carbon monoxide and hydrogen from the second intermediate effluent and yield an intermediate purified stream substantially free of hydrogen and carbon monoxide.

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

• passing the feed air stream through a first hopcalite catalyst layer and produce a first intermediate effluent;
• passing the first intermediate effluent through one or more intermediate layers of adsorbent materials disposed downstream of the first hopcalite catalyst layer, the one or more intermediate layers of adsorbent materials are configured to remove at least carbon dioxide from the first intermediate effluent and produce a second intermediate effluent;
• and
• passing the second intermediate effluent through a second hopcalite catalyst layer disposed downstream of the one or more intermediate layers of adsorbent materials, the second hopcalite catalyst layer configured to yield an intermediate purified stream substantially free of hydrogen.

A pre-purification unit for use with an air-separation unit, the pre-purification unit comprising:

• a pre-purification vessel having an inlet configured to receive a stream of feed air and an outlet configured to direct a purified stream substantially free of water, carbon dioxide, carbon monoxide and hydrogen;
• a first hopcalite catalyst layer configured to remove carbon monoxide and hydrogen from the stream of feed air and produce a first intermediate effluent substantially free of carbon monoxide;
• a second catalyst layer disposed downstream of the first hopcalite catalyst layer, the second catalyst layer configured to remove carbon monoxide and/or hydrogen and yield an intermediate purified stream substantially free of hydrogen and carbon monoxide;
• and
• one or more intermediate layers of adsorbent materials disposed between the first hopcalite catalyst layer and the second catalyst layer and configured to remove at least carbon dioxide from the first intermediate effluent and produce a second intermediate effluent.