A thermal configuration for use during sulfidation and operation is disclosed which may involve multiple of the following heating steps, (a) heating a process feed by a charge heater, heating (b) a process feed stream or a recycle oil stream by heat exchange with a process effluent, heating (c) a process feed stream or a recycle oil stream by heat exchange with a said process feed after having been heated in the charge heater. Furthermore, the steps may be made independent by controlling the ratio of the streams directed to (b) or (c), controlling an amount of feed stream or recycle oil stream by-passed around the heating of (b) or (c) and controlling the temperature of step (a).