Numerical analysis of 3-D microstructure of coke using micro X-ray CT

A finite element model of coke was generated using micro X-ray CT, and coke strength was numerically evaluated using its microstructure. First, three-dimensional (3-D) and two-dimensional (2-D) stress analyses of coke were compared. Next, 3-D stress analyses of cokes produced from caking coal and slightly caking coal were conducted in order to investigate the effect of the 3-D microstructure on coke strength. Furthermore, the strength anisotropy of coke was evaluated by stress analyses assuming a uniaxial tensile test in three directions. We found that the maximum principal stress magnitude and stress concentration area are smaller in the 3-D stress analysis than in the 2-D stress analysis. Moreover, the stress concentration area and strength anisotropy of coke produced from slightly caking coal are larger than those of coke produced from caking coal. The results indicate that stress analysis based on micro X-ray CT images is very useful for investigating the relationship between coke microstructure and strength.