System and method for cryogenic purification of a feed stream comprising hydrogen, methane, nitrogen and argon
AssigneePraxair Technology, Inc.
InventorHenry E. Howard
Life of this patent
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Abstract
A system and method for cryogenic purification of a hydrogen, nitrogen, methane and argon containing feed stream to produce a methane free, hydrogen and nitrogen containing synthesis gas and a methane rich fuel gas, as well as to recover an argon product stream, excess hydrogen, and excess nitrogen is provided. The disclosed system and method are particularly useful as an integrated cryogenic purifier in an ammonia synthesis process in an ammonia plant. The excess nitrogen is a nitrogen stream substantially free of methane and hydrogen that can be used in other parts of the plant, recovered as a gaseous nitrogen product and/or liquefied to produce a liquid nitrogen product.
Claims19
A method for purifying a hydrogen, nitrogen, methane and argon containing feed stream to produce a hydrogen and nitrogen containing synthesis gas and a methane fuel gas, the method comprising the steps of:
- conditioning the feed stream to a temperature near saturation at a pressure greater than 300 psia;
- directing the conditioned feed stream to a synthesis gas rectification column configured to produce a hydrogen and nitrogen enriched overhead vapor stream and a methane-rich condensed phase stream at the bottom of the synthesis gas rectification column;
- directing the methane-rich condensed phase stream to a hydrogen stripping column configured to strip hydrogen from the methane-rich condensed phase stream and produce a hydrogen free methane bottom stream and a hydrogen enriched gaseous overhead;
- vaporizing the hydrogen free methane bottom stream to produce a vaporized hydrogen free methane-rich stream or a partially vaporized hydrogen free methane-rich stream;
- warming the hydrogen and nitrogen enriched overhead vapor stream via indirect heat exchange with the feed stream to produce the hydrogen and nitrogen containing synthesis gas;
- and
- warming the vaporized hydrogen free methane-rich stream or the partially vaporized hydrogen free methane-rich stream via indirect heat exchange with the feed stream to produce the methane fuel gas.
Dependencies are inferred from the claim text.