Apparatus for the catalytic reaction of H.sub.2 -containing feed gas

In an apparatus for the catalytic methanation of a feed gas containing H.sub.2 and CO, said apparatus being of the type including at least one reaction area including a liquid medium containing a catalyst, and means for introducing a feed gas into said liquid medium and said catalyst, to thereby perform a catalytic reaction to produce a gaseous reaction product and to generate heat of reaction which is transferred to said liquid medium, whereby said catalytic reaction occurs at an operational temperature and an operational pressure, the improvement wherein:

• said liquid medium is an extraneous liquid medium comprising a reactor liquid which is stable during said catalytic reaction and which boils at said operational temperature and said operational pressure, producing a reactor liquid vapor, whereby the thus boiling reactor liquid comprises means for maintaining said catalyst at a constant temperature, and said apparatus further comprises a condensation area positioned above said reaction area in which said reactor liquid vapor is condensed to form condensed reactor liquid, means for passing a cooling agent comprising water through said condensation area in indirect heat exchange relation with said reactor liquid vapor, whereby said cooling agent absorbs the heat of reaction from said reactor liquid vapor, means for returning said condensed reactor liquid to said reactor liquid in said reactor, means for employing the thus absorbed heat of reaction to generate steam from said water, said reaction area and said condensation area being within a double-wall reaction vessel having a space between its walls, and means for introducing at least a portion of said steam into said space.