Coke solution-loss degradation model with non-equimolar diffusion and changing local pore structure

Abstract

To provide a more accurate reference for coke quality evaluation, and to achieve the benefits of coking-coal resource use and energy conservation, a coke solution-loss degradation model was developed by combining non-equimolar diffusion, the parallel pore model, the random pore model and an ever-changing local pore structure. The model could predict the coke solution-loss behavior and degradation behavior to improve the understanding of the coke solution-loss degradation mechanism. The model is of value for application by coking and ironmaking workers. The model was verified by the coke overall weight-loss(%) and local porosity after reaction. The predicted results showed a good fit with the experimental data. The CO2 concentration on the coke outer surface and the CO2 concentration distribution in the inner coke decreased because of the effect of non-equimolar diffusion. The coke solution-loss behavior and degradation behavior were presented by a three-dimensional diagram of CO2 concentration and the local inner coke porosity, respectively. The model was verified by the effectiveness factor and coke strength after reaction (CSR25) separately, and the conclusion could be drawn that the gradient distribution of the CO2 concentration and local-porosity inner coke could cause the greatest degradation and yield the worst coke strength after reaction.