锅炉全烧准东煤沾污结渣特性分析

针对燃烧新疆准东煤存在结渣、沾污等问题,在新疆宜化150 t/h锅炉全烧准东煤进行实炉测试试验。在全烧准东煤期间,对锅炉炉膛水冷壁、过热器、低温受热面、底渣的结渣形态观测,对以上各部位渣样取样分析。结果显示,锅炉全部燃烧准东煤时存在严重的结渣与沾污问题。结合实验室试验研究及本次实炉测试试验,认为结渣、沾污主要原因是由于煤中钠的氯化物、氧化物、单质气化后形式挥发到烟气中冷凝在高温管壁,与烟气SO_2、Fe_2O_3等化合生成硫酸盐沉积,煤中铁矿石分解后与CaO、Al_2O_3等形成低温共融化合物,降低灰熔融性温度,增加准东煤灰结渣、沉积倾向,煤中高钙、高水分加速了烟气低温段的积灰。

Analysis of slagging and fouling characteristics in a purely burning zhundong coal boiler

In order to elucidate the problem of severe slagging and fouling during burning Zhundong coal,150 t/h boiler in Xinjiang Yihua company was used to carry out the assessment on all-Zhundong coal operation.The fouling configuration and morphology of water wall panel,super-heater,low temperature tube,and bottom ash were traced,and the slags from different positions were analyzed.The results show that the boiler suffers seriously slagging and fouling during entirely burning Zhundong coal.The slagging and fouling are caused by various forms of Na-bearing materials,such as sodium chloride and sodium oxides as well as elemental sodium released from coal and accumulated on the high temperature metal surface,reacting with SO2 、Fe2O3 to produce sulfates.The Fe-bearing minerals will decompose and combine with CaO,Al2O3 etc to produce low temperature eutectics.Such eutectics can decrease the ash melting temperature and accelerate the slagging and fouling propensity of Zhundong coal.Moreover,Ca and water in coal promote the accumulation of duster in the low temperature tube.