SINGLE COLUMN NITROGEN REJECTION UNIT

Abstract

A system for removing nitrogen from a hydrocarbon feed stream has a heat exchanger system that cools the hydrocarbon feed stream. A feed separator separates the cooled feed stream from the heat exchanger system into a methane-enriched fluid and a nitrogen-enriched first fluid. A helium separator receives the cooled nitrogen-enriched first fluid from the heat exchanger system and produces a helium-enriched first fluid and a helium separator bottoms fluid, directing the helium-enriched first fluid back to the heat exchanger system.A hot helium stripper receives the bottom fluid from the helium separator and the first nitrogen-enriched fluid from the feed separator as the stripping fluid and produces a second helium-enriched fluid and a bottom fluid from the hot helium stripper, directing the bottom fluid from the hot helium stripper to the distillation column. A cold helium stripper receives the first cooled helium-enriched fluid from the heat exchanger system and the second helium-enriched fluid from the hot helium stripper as the stripping fluid and produces a crude helium fluid and a bottom fluid from the cold helium stripper, directing the bottom fluid from the cold helium stripper to the distillation column. A reflux compressor compresses at least a portion of the heated nitrogen-enriched vapor stream from the heat exchanger system.A reflux accumulator receives the cooled, nitrogen-enriched fluid stream from the heat exchanger system and produces a vapor stream from the reflux evaporation drum and a reflux fluid stream, which it then directs to the distillation column. The distillation column produces a nitrogen-enriched vapor stream and a bottoms liquid stream.