Aiming at solving the problems of low efficiency of slag cooler's waste heat utilization system and large heat consumption of air heater in current circulating fluidized bed(CFB) boiler units

a comprehensive optimization system for slag cooler and air heater system is proposed. Taking a typical 350 MW CFB boiler unit as an example

the thermal performance of the optimized system under different working conditions is analyzed in detail. On this basis

the energy saving effect of the optimized system at different ambient temperatures in winter is calculated

and its economic performance is explored. The results show that

taking the case unit as an example

under the condition that the available residual heat of the slag cooler remains unchanged

the power generation coal consumption rate of the unit applying the optimized system in winter can reduce by 2.0 g/(kW·h)

and that in other seasons can reduce by 0.9 g/(kW·h). The average annual net income of the unit can increase by 2.71 million yuan

and both the energy saving effect and economic benefits are significant. In addition

the energy saving effect of the optimized system in winter will be more significant when the ambient temperature is lower.