PURPOSE: To obtain C5+ hydrocarbons with high selectivity while enhancing a CO conversion ratio and reducing the formation of CH4 by bringing H2 containing no light hydrocarbon and CO into contact with each ether in the presence of added water at high temp. in a fixed bed using a catalyst composed of Co and reduced in the net consumption of water.
CONSTITUTION: H2 containing no light hydrocarbon and CO are brought into contact with a catalyst composed of Co in the presence of added water at 180-240°C under 5-30 atmospheric pressure to obtain C5+ hydrocarbons. The addition of water is performed by adding water to supply matter to introduce the same into a reaction zone or by directly adding water to the reaction zone and the addition amt. thereof is set to 1-70 vol.% (pref., 5-30 vol.%) with respect to the total amt. of H2O, CO and H2. Both of CO converting activity and a C5+ hydrocarbons selectivity are increased by adding water to the reaction zone and, at the same time, the formation of methane can be reduced.