Abstract: A method of controlling the heating effect of high temperature gases such as gases obtained in the partial oxidation of oil asphalt, oil shale or coal and the like which are to be used for the heating of another media such as for superheating steam comprises passing the high temperature gases into a space on the way to the heating of the media and circulating a heat absorbing media such as water into the space in quantities to have a selected heat exchange with the high temperature gases and control the temperature thereof on its way to its use in a heat exchanger or superheater. The apparatus include a vessel which is connected between a superheater and a steam producing gas cooler which has an inlet for the high temperature gases which are circulated through the vessel through tubes on its way to the superheater which is disposed over the vessel and advantageously connected to it.