Abstract: The separation energy requirement of a conventional cryogenic process for separating carbon monoxide ("CO") from a gaseous feed containing primarily CO and hydrogen is reduced by an improvement to the process. In the process, CO is scrubbed from a vapor portion of the feed by a liquid methane wash and dissolved hydrogen is stripped from the resultant CO-loaded liquid methane stream. The hydrogen-stripped CO-loaded liquid methane stream is sub-cooled and split into at least first and second substreams. The first substream is expanded and introduced into a CO/methane fractionation column as a liquid feed. The second substream is partially vaporized and introduced into said fractionating column as a two-phase feed. The fractionating column separates the hydrogen-stripped CO-loaded liquid methane feeds to provide CO-rich vapor overheads and methane-rich bottoms liquid. A "high pressure" CO recycle heat pump stream provides reboil to the fractionation column.

Abstract: Hydrogen (4), and carbon monoxide (21) are separated from a gaseous mixture thereof, typically a mixture of essentially hydrogen, carbon monoxide and methane (1) using liquid methane (3) to dissolve carbon monoxide in a methane wash column (2), removing (8) residual hydrogen (15) from the loaded methane wash (6,9), and separating (18) the residual loaded methane into carbon monoxide and methane fractions (21,22). The residual hydrogen (15) is removed in a hydrogen stripping column (8), said column being refluxed with a methane rich scrubbing liquid stream (13) withdrawn from an intermediate location of the methane wash column (2).

Abstract: Carbon monoxide is separated from a gaseous mixture containing hydrogen and carbon monoxide and contaminated with nitrogen by partially condensing the mixture to provide a hydrogen-enriched vapor feed fraction and a carbon monoxide-enriched liquid feed fraction; separating nitrogen from carbon monoxide in said liquid fraction in a distillation column to provide nitrogen-freed liquid carbon monoxide bottoms and nitrogen-enriched vapor overheads; condensing at least a portion of said overheads against a recycle heat pump stream derived from said gaseous mixture and containing hydrogen and carbon monoxide; and returning at least a portion of said condensed overheads to said nitrogen-separation column as reflux. The recycle heat pump stream usually is provided by condensation from the hydrogen-enriched vapor feed fraction and/or by separation from the carbon monoxide-enriched liquid feed fraction.