On the basis of feed water equivalent enthalpy rise method(the conventional method)

by regarding the regenerative system with secondary reheat and hybrid heater as the model

the relationship equation between the regenerative system efficiency and the extraction steam enthalpy was developed.Considering the maximal regenerative system efficiency as the objective function

the recursive relations between the extraction steam enthalpy of the adjacent two stages heater were derived.Then the optimal extraction steam enthalpy of the steam turbine was asertained.This method was applied to a 1 000 MW double reheat unit to determine the reasonable extraction steam enthalpy.The results show that

compared with conventional method

the extraction location distribution determined by this method is more even and reasonable

the regenerative system efficiency is 0.1% higher and the total exergy loss of the heater is 1.37kJ/(kg·MW)lower.This method puts forward a new research direction and guidance for how to determine the regenerative extraction steam parameters.