Separation of carbon monoxide from nitrogen-contaminated gaseous mixtures also containing hydrogen

摘要

Carbon monoxide is separated from a gaseous mixture (1) containing hydrogen and carbon monoxide and contaminated with nitrogen by partially condensing (H201 & H202) the mixture to provide a hydrogen-enriched vapour feed fraction (5) and a carbon monoxide-enriched liquid feed fraction (3); separating nitrogen from carbon monoxide in said liquid fraction in a distillation column (V205) to provide nitrogen-freed liquid carbon monoxide bottoms (42) and nitrogen-enriched vapour overheads (43); condensing (H204) at least a portion of said overheads (43) against a recycle heat pump stream (34) derived from said gaseous mixture (1) and containing hydrogen and carbon monoxide; and returning at least a portion of said condensed overheads to said nitrogen-separation column (V205) as reflux. The recycle heat pump stream (34) usually is provided by condensation (H203) from the hydrogen-enriched vapour feed fraction (5) and/or by separation (V203) from the carbon monoxide-enriched liquid feed fraction (3).