by the economizer is delivered into the steam drum the drum water is circulated in the steam drum evaporator system and a proportion of it is evaporated in the process the separation of water and steam takes place in the steam drum the water is fed back to the evaporator while the steam passes to the steam turbine installation either directly or via a superheater which may optionally be present the flow through the evaporator may be configured as a natural circulation or a forced circulation in the case of forced circulation by way of example corresponding pumps are required however the individual pressure stages of the heat recovery steam generator may also be designed in accordance with the principle of the once through forced circulation evaporator of course it is additionally possible for further systems which are not mentioned here to be present within the water steam cycle an optional recirculation system for increasing the condensate side inlet temperature into the heat recovery steam generator should be mentioned for the region of the heat recovery steam generator specifically the condensate preheater 15 in order to prevent corrosion on the exhaust gas side caused by the gases dropping below the dew point finally after it has flowed through the heat recovery steam generator 8 the exhaust gas 7 is released into the atmosphere via a stack 9.