Flying slag particles have a tendency to deposit and sinter on the exit wall of entrained coal gasifiers. Sintering behavior was examined using water quenched slag and char obtained by the Taiheiyo coal gasification at the pilot plant of HYCOL (Research Association for Hydrogen from Coal Process Development). This plant was designed to gasify 50 tons of coal per day. In this paper the compressive strength was measured and used to estimate the sintering temperature . The sintering temperature of the slag was approximately 800°C, whereas that of the standard JIS ash was 1050°C. It was also found that the presence of carbon in the slag hindered the progress of sintering. When the concentration of carbon in the slag was above 4%, the slag did not sinter even at 900°C. SEM and EDX analyses showed that the carbon in the slag acted as a dispersant. The X-ray diffraction for the cold slag could hardly detect peaks because it was quenched and amorphous. However, the peak intensity of Anorthite detected in the heat treated slag and the JIS ash. The peak intensity of Anorthite was increased with increasing heat treatment temperature and time, but not much affected by the carbon content. This suggests that the slag melts partially regardless of the carbon content, but the carbon hinders the progress of sintering.
