Effect of changes in mechanical properties of coke matrix caused by CO₂or H₂O gasification reaction on the strength of lump coke

In this study, we evaluated the effect of the CO₂or H₂O gasification reaction on the mechanical property of the coke matrix by measuring the elastic modulus of the coke matrix before and after the gasification reaction. We also investigated the effect of the distribution of the elastic modulus in the coke matrix on the strength of the lump coke by conducting the fracture analysis for the coke model with porosity of 0-0.4 in which the distribution of the elastic modulus obtained by the experiment was reflected. The nanoindentation measurements of the elastic modulus of the coke matrix before and after the gasification reaction implied that the distribution of the elastic modulus in the coke matrix differs depending on the gasification agent. In the case of the CO₂gasification reaction, both the coke matrices with high and low elastic moduli were consumed by the gasification. On the other hand, in the case of the H₂O gasification reaction, only the coke with an elastic modulus of over 30 GPa before the reaction was consumed by the gasification reaction. Also, the numerical results showed that the distribution of the elastic modulus in the coke matrix affects the strength of the coke model with low porosity whereas the one did not affect that with high porosity.