The research status of the combined system of low pressure economizer and air heater was introduced. By taking a 660 MW unit in Shandong Province as the example

the influence of heat exchange area of low pressure economizer and outlet air temperature of air heater on energy conservation potential

static investment and static payback period of the whole system was calculated. The result shows that

the larger the heat exchange area of low pressure economizer

the greater the energy conservation potential and static investment. The static payback period of the system decreases at first and then increases with the increaing heat exchange area of the low pressure economizer. The higher the air temperature at the air heater outlet

the greater the energy conservation potential and static investment. The static payback period of the system decreases at first and then increases with the increasing air temperature at the air heater outlet. It is recommended that the low pressure economizer be arranged with 40 rows in vertical direction

and the air temperature at the air heater outlet be 65~75 ℃.