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

摘要

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.