中文摘要：

中国的准东煤储量巨大，但由于其Na、Ca含量较高，燃烧准东煤的锅炉炉膛出口过热器表面上结渣和沾污问题严重。为了阐明其结渣机理，对某350MW锅炉出VI屏式过热器（烟气温度1000℃左右）的焦样进行分析，发现焦体内部存在明显的分层结构，不同层焦样中元素含量明显不同．化合物形态也存在较大差异。这是由于在焦体发展过程中，随着沉积表面温度逐渐升高．焦体的灰颗粒之间发生差异较大的物理化学反应而形成的。通过对不同层焦样的化合物形态进行整理并详细分析．最终提出了各层不同化合物的形成机理。

英文摘要：

The reserves of Zhundong （ZD） coal in China are huge. However, due to its high contents of Na and Ca, slagging and fouling are serious on the surface of the platen superheater at the furnace outlet area （at the flue gas temperature of around 1 000 ℃）. In this paper, to explore the mechanism of the slagging in the high alkali coal combustion process, study is conducted on the slag samples from the platen superheater of a 350-MW boiler. With the study, an obvious layered structure is observed in the slag, and the element compositions and compounds in each layer are very different. This is because in the developing of slags, with the deposite temperature rising, different physical-chemical reactions happen in the ash particles. Through the classification and the detailed analysis on the compounds in each layer, the formation mechanisms of those different compounds are proposed.