Abstract: In order to solve the problem of excessively high temperature of exhaust gas,a low pressure economizer was installed in the tail flue to reduce the fuel gas temperature and increase the thermal economy of the unit.The layout schemes were proposed according to the design discipline and parameter requirement by systematically considering the sulfur contamination,abrasion of tube wall,and enthalpy rise constraint among the heat regenerative systems. The thermal economy of proposed schemes was evaluated using equivalent enthalpy drop method.The results show that scheme 3 achieves higher thermal economy than others.It can reduce the coal consumption to 1.517 g/k Wh at rated load.The low pressure economizer presents better energy saving effect,and it can be beneficial as energy saving reference for other same type units.