The object of the present invention is to obtain a carbon-monoxide removing technique
capable of very effectively reducing/removing carbon monoxide present at one thousand
of ppm to several % in a hydrogen-rich treatment-object gas such as a reformed
gas obtained by reforming of a fuel such as natural gas, methanol, etc. to a concentration
of several tens of ppm (preferably 10 ppm) or lower without excessive loss of hydrogen,
even when carbon dioxide, methane are co-existent For accomplishing this object,
there are provided two stages of CO removers for removing carbon monoxide from
a hydrogen-containing treatment-object gas, the first-stage CO remover removing
a portion of the carbon monoxide by methanation thereof through a catalyst reaction,
the second-stage CO remover removing the remaining portion of the carbon monoxide
mainly by oxidation thereof through a further catalyst reaction involving addition
of an oxidizing agent.
