The design features and advantages of the combined system of low pressure economizer and air heater(CSLPEAH)were introduced.This system uses low pressure economizer(LPE)to heat condensation water and part of the condensed water at the LPE outlet to heat the air heater

which make the air temperature at the air preheater inlet be increased to 70 ℃.Other part of the condensed water crowd out the steam turbine extraction

which can improve the turbine work ability and reduce the coal consumption.Moreover

comparison of energy saving effect was carried out between the CSLPEAH and LPE system.The results show that

the energy conservation potential of the CSLPEAH is 0.97g/(kW·h)higher than that of the LPE system

the main energy conservation potential comes from economizing the steam consumption of the original air heater.The energy conservation potential of the CSLPEAH is worse at lower load.