Generally

the exhaust gas temperature in domestic coal-fired units is relatively high.Aiming at solving this problem

the flue gas waste heat recovery technology was proposed to carry out technical transformation for the unit.By introducing the concept of "relative efficiency"

the "relative efficiency" thermodynamic calculation model was established.Moreover

considering the " relative efficiency" and economic benefits as a comprehensive index

the influence of such key factors as flue gas parameters

condensate parameters and heat exchanger's structural parameters on overall performance of the flue gas waste heat recovery system was investigated.On the premise of ensuring the unit safety operation

the corrosion resistance

performances of the system like the wear resistance and ash deposition resistance should be considered to optimize the system by regulating the parameters mentioned above.Taking a 600 MW unit as the example

the calculation results show that

after the optimization

the equipment mass of the system decreased by 3.9%

the relative efficiency increased by 4.4%.