A heat exchange system for producing superheated working fluid for a steam turbine from expected supercritical hydrothermal fluid from a geothermal reservoir, including a header-type heater with a shell is provided. An inlet is conducted to a feed pipe for transporting the expected supercritical hydrothermal fluid from the geothermal reservoir into the shell and where an outlet is conducted to a drain pipe for transporting the condensed hydrothermal fluid from the shell to a disposal, working fluid pipes circulating feed water from a condenser of the steam turbine into a heat exchange bundle system within the shell and retrieving superheated steam from the heat exchange bundle system for the steam turbine, a spraying device is arranged within the shell for spraying a first bundle of the heat exchange bundle system, and a mixing device is provided.
