Research on the slagging characteristics of Shenhua coal

Shenhua coal is one of high-quality power coals of high calorific value that has large reserves in China. But the low fusion point of its ash poses some problems for its application in thermal power plants. The experiments were carried out in a 0.25 MW combustion facility to make a comparative study of the ash deposition and slagging process of Shenhua coal and XmWen coal. The results show that the ash deposition process of Shenhua coal lasts longer than that of Xinwen, and self-cleaning of the slag does not take place with the Shenhua coal. Also, the ash deposition of Shenhua coal decreases the heat transfer of the furnace wall severely. The three slag or ash specimens, sampled in the furnace, near the furnace wall and in the flue duct, were tested and analyzed. It was indicated that the furnace wall slag is rich in iron while in the fly ash calcium content is higher. The slag near furnace wall had a larger ratio of silicon to aluminum, more glassy matter and smaller crystal characteristic peaks in the X-ray diffraction (XRD) pattern. The crystalline matter is mostly quartz in the furnace wall slag. The crystal characteristic peaks in XRD in the fly ash are larger than those of the furnace wall slag. The crystalline matter of the fly ash are quartz, andalusite and hematite. (c) 2007 Curtin University of Technology and John Wiley & Sons, Ltd.