Abstract: So far the impacts of air-cooling dry-type bottom ash handling system on boiler efficiency are still controversial and very few authoritative conclusions have been drawn. After three years’ research on the system, the mathematical models including boiler efficiency and cooling air volume are established. Combining with the tests conducted in two 1 000-MW boilers of one power plant, it is concluded that the dry-type bottom ash handling system does have impacts on boiler combustion and lower the boiler efficiency under most circumstances. In addition, the impacts of the dry-type bottom ash handling system are greater than those of the wet-type system. The easy-cooking coal is not a suitable choice for the boilers with dry-type system. If the coal quality of the power plant fluctuates drastically, it is critical to choose the dry-type system meticulously.

Key words: dry-type ash handling system, wet-type ash handling system, boiler efficiency