Device for selective catalytic oxidation of carbon monoxide

A multi-stage unit for selective catalytic oxidation of carbon monoxide (CO) in a stream of hydrogen (H2)-rich gas mixture, in which each stage has CO oxidation zone(s), can be cooled and can be supplied with oxidant on the inlet side, has NOTLESS 3 cooled CO oxidation stages. The first two have a common cooling cycle; and the third has an independent cooler and is a combination reactor, in which the cooler is used for reforming a H2-rich medium.