A continuous process for producing simultaneously a stream of cooled clean synthesis gas, reducing gas, or fuel gas and a separate stream of superheated steam. In the subject process a hydrocarbonaceous fuel is reacted with a free-oxygen containing gas by partial oxidation in the reaction zone of a free-flow noncatalytic gas generator. The effluent gas stream from the reaction zone is quenched in water in a quench zone and further cooled by being passed serially through first and second heat exchange zones to produce a product gas stream of cooled clean synthesis gas, fuel, or reducing gas. Simultaneously, a stream of boiler feed water is converted into superheated steam by stepwise sequential indirect heat exchange with the following sources of heat: first with a stream of carbon-quench water dispersion from said quench zone, second with said effluent gas stream in said second heat exchange zone, and third with the effluent gas stream in said first heat exchange zone. Optionally, the process gas stream may be cooled further, scrubbed with water, passed through a separating zone to remove entrained water, and expanded in a gas turbine for the production of mechanical or electrical energy.