Method and device for producing a synthesis gas containing H2 and CO

An apparatus for performing the method for producing gas containing H2 and CO by catalytic conversion of hydrocarbons contained in a feed gas stream with steam, in that the feed gas heated to 300 to 400° C. and subsequently desulfurized is mixed with steam, the mixture of feed gas and steam is preheated by heat exchange at a pressure of 10 to 45 bar to a temperature of 300 to 700° C., and is subsequently heated over a catalyst by heat exchange at a pressure of 10 to 45 bar to a temperature of 650 to 950° C., wherein a catalyst bed contained in a vertical reaction tank is traversed by the mixture of feed gas and steam and is indirectly heated by thermal radiation and convection, wherein the vertical reaction tank includes a tube bundle comprising axially parallel, internally heatable radiant tubes closed at the bottom, in each radiant tube a flame tube concentrically is inserted by forming an annular space, said flame tube comprising apertures located in a middle section of the flame tube, and in each flame tube a gas lance concentrically is inserted by forming an annular space, and a reaction space to be traversed by the mixture of feed gas and steam is filled with a catalyst bed around the radiant tubes, wherein the reaction space of the reaction tank is filled with a catalyst bed up to a height of 30 to 75% of the overall height of the tube bundle.