System and method for argon recovery from 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 argon and nitrogen extraction from a feed stream comprising hydrogen, methane, nitrogen and argon, such as a low-pressure tail gas of an ammonia production plant is provided. The disclosed system and method provides for a rectification system wherein an argon depleted gaseous stream and a methane rich liquid stream are produced and subsequently combined in whole or in part prior to vaporization. Nitrogen and argon containing streams may also be produced from the rectification system. An argon stripping column arrangement is also disclosed where residual argon is removed from the methane-rich fuel gas and recycled back to the feed stream.
Claims20
A method for separating a feed stream comprised primarily of hydrogen, nitrogen, methane and argon, the method comprising the steps of:
- conditioning the feed stream to a temperature, pressure and composition suitable for rectification at a pressure less than or equal to about 400 psia;
- directing the conditioned feed stream to a rectification system which is comprised of at least one rectifying column;
- separating the conditioned feed stream in the at least one rectification column to produce an argon depleted nitrogen enriched vapor stream, an argon enriched stream, and a methane-rich liquid stream;
- combining the methane rich liquid stream and a portion of the argon depleted nitrogen enriched stream to form a combined two phase fuel stream;
- directing the two phase fuel stream to an indirect heat transfer device;
- and
- warming the two phase fuel stream in the indirect heat transfer device to produce a fuel gas stream.
Dependencies are inferred from the claim text.