THE MINERALOGY ANALYSIS OF ASH DEPOSITION IN REFRACTORY ZONES IN A W-FLAME BOILER
To understand the effects of mineral species of low volatile coals on ash depositions in refractory zones, this paper used optical microscope and X-ray diffraction (XRD) to analyze the deposited ash, fly ash and pulverized fuels collected from a 600 MW W-flame boiler. The slag in the refractory zones was composed of two layers which had significantly different morphology and microstructure, although the crystal components in them, including mullite, cristobalite and anorthite, are very similar. Pyrite caused the formation of rufous and hard inner slag layer, and the formation of grey-white, friable outer slag layer, as the result of the solid state reaction producing anorthite. Some tobelite were present in the fuels having the similar crystal structure as illite, but it could not initiate slagging like illite did because its interlayer cation was mainly NH4+ rather than K+. The cristobalite present in the slag may be originated from the amorphous silica attributed by kaolinite decomposition during the fuels combustion. The key to prevent slagging deterioration in the refractory zones in boiler is to limit the usage of high pyrite fuels. The low volatile coals in North China possibly have the similar slagging characteristics.
slagging low volatile coals refractory zones tobelite pyrite XRD
Sida TIAN Yuqun ZHUO Changhe CHEN Dingkai LI
Department of Thermal Engineering, Tsinghua University, Beijing China
国际会议
第六届煤燃烧国际会议(The 6th International Symposium on Coal Combustion)
武汉
英文
253-257
2007-12-01（万方平台首次上网日期，不代表论文的发表时间）