Aiming at solving the problem of high boiler exhaust gas temperature and large exhaust heat loss in power plants

taking a 330 MW subcritical unit as an example

a complete system model including boiler

steam turbine and generator is set up using the Ebsilon software. Based on this model

thermal characteristics simulation is conducted on the combined system of normal low temperature economizer and the combined system of air heater and low temperature economizer. The characteristics of the combined system is analyzed with different air heater outlet temperatures

and the effects of air heater outlet temperature on turbine heat rate

boiler efficiency

power generation coal consumption

auxiliary power consumption and power coal consumption are also analyzed. The results show that

the combined system of air heater and low temperature economizer has great potential in energy saving. The combined system can save more 0.5~0.9 g/(k W·h) of coal than the normal low temperature economizer. When designing the temperature of the air heater outlet

the decrease of power coal consumption increases with the air heater outlet temperature. However

when the temperature goes up to a certain extent

the energy saving capacity no longer increases.