Effect of random pore shape, arrangement and non-adhesion grain boundaries on coke strength

The coke strength is determined by coke microstructure and non-adhesion grain boundaries. The aim of this study was to investigate the effects of pore structure and non-adhesion grain boundaries on fracture behavior by RBSM (Rigid Bodies-Spring Model). In regard to pore structure, randomly-shaped pores were generated, and the pores were randomly-arranged. The randomly-shaped pores were controlled by equivalent circle diameters and pore roundness. The non-adhesion grain boundaries were randomly-located in coke matrix. First, coke with realistic pore structure was calculated. As a result, large and distorted pores affected decreasing of the coke strength. Furthermore, a coke model which was composed of coke matrix, pores, and non-adhesion grain boundaries was analyzed. The coke strength was decreased, resulting in an increase of existence of non-adhesion grain boundaries. The numerical data was corresponded to the experimental result. The coke strength was decreased when there are a little bit of non-adhesion grain boundaries. This is because that a non-adhesion grain boundary becomes an origin of the fracture if the non-adhesion grain boundary is in a stress concentration region. It was shown that non-adhesion grain boundaries were the factor of decreasing of the coke strength with low-quality coal.