Abstract: Coal is gasified, to yield a fuel gas having a medium-B.T.U. heating value, in the presence of air and steam in a plurality of reaction stages having different reaction temperatures. Reaction heat is principally supplied directly by recycle of char particles from a separate combustion zone to higher-temperature reaction zones and indirectly by combustion flue gas to lower-temperature reaction zones. Hydrogen sulfide, from product fuel gas, and flue gas are directly contacted to provide elemental sulfur. The only other product is a substantially non-combustible ash.