This invention relates to the production of hydrogen-rich gas by the partial oxidation of a saturated gaseous hydrocarbonaceous fuel or a mixture of saturated gaseous hydrocarbonaceous fuel and a liquid hydrocabonaceous fuel in a gas generator. In the process, a saturated gaseous hydrocarbonaceous fuel from a subsequent fuel gas saturator is preheated by indirect heat exchange with a portion of shifted process gas stream from a catalytic water-gas direct shift conversion zone and reacted in said partial oxidation gas generator. The process gas stream from the noncatalytic partial oxidation gas generator is quench cooled and scrubbed with water and preheated by indirect heat exchange with a second portion of the process gas stream from the shift conversion zone prior to catalytically reacting the CO and H.sub.2 O in the process gas stream in the shift conversion zone to increase its H.sub.2 content. The shifted process gas stream is cooled and dewatered to produce shift condensate which is used to saturate the aforesaid preheated gaseous hydrocarbonaceous fuel feedstream to the partial oxidation gas generator.