Abstract: A reforming process for the production of hydrogen or synthesis gas is improved by a preparatory process including the preheating of gaseous hydrocarbons within a heat exchange zone into which water is sprayed to obtain concurrently evaporation of water and preheating of the water vapor as well as mixing of the hydrocarbon gases being preheated with the steam as produced, and preheating of the entire blend will continue prior to charging the reformed process.