Abstract: A process for converting sulfur-containing carbonaceous fuel into a combustible product gas is described. The fuel, in the form of fine particles, is mixed with a first aqueous solution containing dissolved alkali metal carbonate at approximately atmospheric pressure to form concentrated slurry. The slurry is pressurized and fed into a gasifier operating at an elevated pressure. An oxygen-containing gas is also fed into the gasifier where it reacts with the fuel to produce hydrogen and carbon monoxide-containing gases and heat the reacting mixture to about 900-1400° C. Oxygen combined with steam may also be used as the oxidizer to produce hydrogen-rich product gas. Alkali metal salts in the slurry are melted and absorb sulfur from the reacting fuel to form a liquid smelt containing alkali metal sulfide.