In the high temperature ultra supercritical double-reheat units

the heat recovery effect of the regenerative heat system is weakened after twice reheat

and the superheat degree of the extraction steam is also increased. To solve this problem

this paper applies heat recovery steam turbine to optimize the heat regenerative system of the high temperature ultra supercritical double-reheat unit. Moreover

by taking the externally arranged cascade steam cooler as the comparison

the calculation model for the externally arranged steam cooler and the heat recovery steam turbine were established respectively. The influence of the heat recovery steam turbine on thermal economy of the the conventional ultra supercritical units and high temperature ultra supercritical double-reheat units was studied. The results show that

applying the heat recovery steam turbine could improve the efficiency of the original steam turbine. According to the fact that the present inner efficiency of the heat recovery steam turbine is 90%

the standard coal consumption of the unit could be reduced by about 0.633 g/(k W·h) when using the heat recovery steam turbines' s extraction and exhaust as the steam supply of the 5th and 6th heater. The efficiency of the original steam turbine could be enhanced by about 0.25% and the standard coal consumption of the unit could be reduced by about 0.689 g/(k W?h) when using the heat recovery steam turbine's extraction and exhaust as the steam supply of the deaerator. Compared with setting externally arranged steam cooler

applying the heat recovery steam turbine can make full use of the extraction steam's superheat and further improve the economy of the thermodynamic system

which has huge potential of energy conservation.