Linde Aktiengesellschaft

Hans Jungfer

Hans Becker

Wolfgang Schmid

Herwig Landes

Olaf Brauer

A process is disclosed for the purification of a gaseous mixture, for example, consisting essentially of hydrogen and containing impurities, e.g., carbon monoxide, methane and argon. The gaseous mixture is scrubbed with liquid nitrogen in a scrubbing column having two sections. In order to be able to process the residual gases formed during the scrubbing step, containing especially CO, argon and CH.sub.4, in a simple way and without great investment costs, liquid nitrogen is introduced in a quantity sufficient for an almost complete scrubbing out of the carbon monoxide, and a partial amount of the scrubbing liquid, enriched with carbon monoxide, is withdrawn between the upper and lower sections. The partial amount withdrawn is dimensioned so that the residual quantity of scrubbing agent delivered to the lower section of the scrubbing column is enough to scrub out the methane from the gaseous mixture, but yet also leaves a major portion of the carbon monoxide in the gaseous mixture.

Process for purifying a gaseous mixture

For the production of hydrogen, hydrocarbons are subjected to a partial oxidation, the resulting gaseous fraction is fed to a CO shift conversion and the acid gases are removed by absorption. To obtain a H.sub.2 product with a purity of at least 99% by volume without reduction in yield, sulfur compounds are removed in a first absorption stage with an organic, physical solvent; the resultant desulfurized gas is subjected to a selective catalytic oxidation with oxygen to selectively convert CO to CO.sub.2, and resultant desulfurized CO-depleted gas is treated in a second absorption stage with preferably the same scrubbing agent as first absorption stage to remove CO.sub.2.

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Planegg, Germany

Hans Jungfer