| 摘要 |
The present invention is a process for prefractionating a pressurized, helium-containing feed gas mixture (typically containing helium, natural gas and nitrogen) to produce a helium-enriched stream which comprises the following steps: (a) the pressurized, helium-containing feed gas mixture is liquefied and subcooled by indirect heat exchange; (b) the liquefied, subcooled, pressurized, helium-containing feed gas mixture is expanded whereby it is partially vaporized, thus producing a partially vaporized frationation feed stream; (c) the partially vaporized frationation feed stream is stripped in a cryogenic distillation column thereby producing as an overhead, the helium-enriched stream, and a bottoms liquid, the helium-lean stream; and (d) the cryogenic distillation column is reboiled by vaporizing at least a portion of the helium-lean stream. The present invention is also applicable as an improvement to a process for the production of a crude helium product (i.e., > 30 vol% helium).
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