Effect of char on the melting characteristics of coal ash

The effect of char on the melting characteristics of coal ash was studied in the argon atmosphere using an ash fusion determinator connected with a camera and a computer. The results show that the coal char in ash has remarkable influence on the ash melting points as well as the ash melting behavior. The effects are related to the coal rank and the char content addition. For the coal ashes investigated, the deforming temperatures (DT), the softening temperatures (ST), and the flowing temperatures (FT) of all samples with the addition of coal char are higher than those of corresponding initial ashes. The ash melting points increase with the addition of coal char. When the content of coal char is 20% and when the temperature reaches or exceeds the corresponding original ash melting point, an infusible skeleton can be formed because of the sticking interaction between char and ash. When the skeleton formed, the softening temperature and flowing temperature of the sample are difficult or impossible to occur.