CFB锅炉排放循环灰提高锅炉整体性能研究

STUDY ON ENHANCING THE INTEGRATED PERFORMANCE OF LARGE-SCALE CFB BOILER BY DISCHARGING THE CIRCULATED ASH

循环流化床(CFB)锅炉燃用高灰分劣质燃料时,高灰分将对炉内灰平衡产生明显影响,并进而影响CFB锅炉的炉内燃烧、传热、磨损以及粉尘污染物的排放等。从CFB锅炉炉内物料平衡出发,提出了可燃质循环倍率概念,并将其用于炉内灰平衡及CFB锅炉燃烧高灰分燃料时排放循环灰的研究。结合某50 MW CFB锅炉的实炉试验,设计了5 MW CFB锅炉的循环灰排放系统。

For circulating fluidized bed （CFB） boiler firing low-grade fuel with high ash content, the high ash content can affect the ash balance in furnace, and then affecting combustion, heat transfer, erosion, and dust emission performance etc, of the CFB boiler. Starting from substance balance in the furnace of CFB boiler, a fully new conception of Combustible Circulation Ratio has been put forward, and being used to study the ash balance in furnace and verify the necessity of discharging circulated ash during the CFB boiler firing fuel with high ash content. Comined with field test of a 50 MW CFB boiler firing coal with high ash content, the influence of high ash content and discharge of circulated ash upon boiler operation has been studied. Based on this, a discharging system of circulated ash for a 50 MW boiler has been designed.