Soot formation is suppressed in the preparation of hydrogen and/or carbon monoxide
rich gas by arranging on at least a surface of an upper portion of a reactor a
catalytic material which is active in steam reforming hydrocarbons, introducing
a hydrocarbon feedstock and an oxygen-containing atmosphere into the upper portion
of the reactor, partially oxidising the feedstock with oxygen in the upper portion
of the reactor, and contacting a part of the partially oxidized feedstock with
the reforming catalyst in the reactor upper portion.
