Fracture Behavior in Blending Coke Using the Model Compound of Low-quality Coal

The adhesion failure of coke with low-quality coal affects its strength. However, it would be difficult to specify the interface between caking coal and low-quality coal where the adhesion failure arises. In this study, the interface was specified using alumina beads that can be identified by the X-ray CT (computed tomography) as a model compound of low-quality coal, and thus fracture behavior of coke assuming that low-quality coal was blended was investigated experimentally and numerically. To quantitatively evaluate the adhesiveness between coke matrices and alumina beads, the three-dimensional structure of coke was evaluated by the X-ray CT. As a result, the adhesiveness decreased with an increase in the volume ratio of alumina beads, while the adhesiveness was not related to the particle diameter. Also, the fracture strength of coke decreased with an increase in the volume ratio and the particle diameter of alumina beads. For the fracture analysis using RBSM (Rigid Bodies-Spring Model), the fracture strength was also negatively correlated with the volume ratio and particle diameter of alumina beads. Focusing on fracture behavior of coke model, the interface between coke matrices and alumina beads fractured at the non -uniform part where alumina beads existed closely. Therefore, this study suggested that the distribution of low-quality coal within the coke as well as the adhesion failure has an effect on strength of coke with low-quality coal.