초록 ▼

Nitrogen is removed from a natural gas feed stream by a cryogenic distillation process in which said feed stream is fed to a primary column of a distillation column system having a primary column and a secondary column fed from and operating at substantially the same pressure as the primary column.

Nitrogen is removed from a natural gas feed stream by a cryogenic distillation process in which said feed stream is fed to a primary column of a distillation column system having a primary column and a secondary column fed from and operating at substantially the same pressure as the primary column. At least a portion of a primary column methane-rich bottoms liquid is expanded and at least partially vaporized in heat exchange with a condensing primary column nitrogen-enriched vapor. The at least partially condensed primary column nitrogen-enriched vapor is returned to the primary column to provide higher temperature reflux to the distillation column system. A secondary column methane-rich bottoms liquid is at least partially vaporized in heat exchange with a condensing nitrogen-rich overhead vapor to produce a further methane-rich product. At least a portion of the at least partially condensed nitrogen-rich overhead vapor portion is returned to the primary or secondary column to provide lower temperature reflux to the distillation column system.

대표청구항 ▼

A cryogenic process for the removal of nitrogen from a natural gas feed stream comprising nitrogen and hydrocarbons primarily having a carbon content between 1 and 8 carbon atoms comprising: (A) feeding said feed stream to a primary distillation column of a distillation column system, said system pr

A cryogenic process for the removal of nitrogen from a natural gas feed stream comprising nitrogen and hydrocarbons primarily having a carbon content between 1 and 8 carbon atoms comprising: (A) feeding said feed stream to a primary distillation column of a distillation column system, said system providing a primary column methane-rich bottoms liquid from the primary column, a secondary column methane-rich bottoms liquid from a secondary distillation column fed from and operating at substantially the same pressure as the primary column, a primary column nitrogen-enriched vapor from the primary column, and a nitrogen-rich overhead vapor; (B) reducing the pressure of and at least partially vaporizing at least a portion of the primary column methane-rich bottoms liquid in heat exchange with at least a portion of the primary column nitrogen-enriched vapor to produce a methane-rich product and to at least partially condense the primary column nitrogen-enriched vapor; (C) returning at least a portion of the at least partially condensed primary column nitrogen-enriched vapor to the primary column to provide higher temperature reflux to the distillation column system; (D) reducing the pressure of and at least partially vaporizing at least a portion of the secondary column methane-rich bottoms liquid in heat exchange with at least a portion of the nitrogen-rich overhead vapor to produce a further methane-rich product and to at least partially condense said nitrogen-rich overhead vapor portion; and (E) returning at least a portion of the at least partially condensed nitrogen-rich overhead vapor portion to the primary or secondary column to provide lower temperature reflux to the distillation column system.