A steam
methane reforming method in which a feed
stream is treated in a reactor containing a catalyst that is capable of promoting both hydrogenation and
partial oxidation reactions. The reactor is either operated in a
catalytic hydrogenation mode to convert olefins into saturated hydrocarbons and / or to chemically reduce
sulfur species to
hydrogen sulfide or a catalytic oxidative mode utilizing
oxygen and steam to prereform the feed and thus, increase the
hydrogen content of a synthesis gas produced by a steam
methane reformer. The method is applicable to the treatment of feed streams containing at least 15% by volume of hydrocarbons with two or more carbon atoms and / or 3% by volume of olefins, such as a
refinery off-gas. In such case, the catalytic oxidative mode is conducted with a steam to carbon ratio of less than 0.5, an
oxygen to carbon ratio of less than 0.25 and a
reaction temperature of between about 500° C. and about 860° C. to limit the feed to the steam
methane reformer to volumetric dry concentrations of less than about 0.5% for the olefins and less than about 10% for alkanes with two or more carbon atoms.