Evaluation of coal thermoplastic and dilatation behavior with coke pore structure analysis

Abstract

Coke strength is depends on coal thermoplastic and dilatation behavior, so it is very important to understand the behaviors for making high strength coke. In this study, change of coke pore structure were investigated with image analysis of coke cross section when coal combination of blended coal changed and ASP was added to blended coal. (1) When thermoplastic temperature between low rank coal and high rank coal widely differed, low circularity pore increased in the both texture derived from low rank coal and high rank coal. It was concluded that when low rank coal particle dilated, high rank coal particle didn't dilate, so low rank coal particle reached free expansion. Meanwhile, dilatation of high rank coal neighboring low rank coal decreased. As a result, high rank coal not neighboring low rank coal reached free expansion, and low circularity pore area increased in the texture derived from high rank coal. (2) When ASP was added to blended coal, low circularity pore decreased in the texture derived from high rank oal. It was thought that ASP lowered softening temperature of high rank coal, so high rank coal ould fill void between coal particles before low rank coal solidified. As above, investigation of coke pore structure is effective to understand coal thermoplastic and dilatation behavior.