Thermal-design for a low temperature economizer added on a 220 MW unit boiler was carried out.This low temperature economizer applied H type fins tubes

and was laid between the air preheater and the dust remover.Via heating the condensate water through exhaust heat

the economizer can make the exhaust temperature decrease from 160℃to 135℃.The distribution parameter mathematical model of the low temperature economizer was established and the simulation test was performed.The results show that

the error between the simulation results and the corresponding theoretical computation data was small

indicating this model has relative high static accuracy

which is beneficial to evaluating the safety and reliability of the low temperature economizer system correctly.