Abstract
Recent years various trials to improve operation efficiency of blast furnace by combining the decrease in operation temperature and the increase in reaction rates. An increase in coke reactivity is one of the approaches to decrease thermal reserve zone temperature in blast furnace. Although the mechanism to improve the efficiency by increasing the reactivity is explained by the static models like the Rist diagram, these models are incapable of estimating the temperature decrease by the reactivity increase. In this study numerical simulations of blast furnace operation using a mathematical model based on the kinetic theories were performed. In the simulations, descending motions of burden materials were tracked and the reaction behaviors of coke particles along the trajectories were discussed in details through the method of chemical reaction engineering. The results showed that the increase in the coke reactivity lowers the temperature of upper part of the furnace. In the studied range of the reactivity, the reaction scheme of the solution loss reaction in thermal reserve zone varied from uniform reaction to surface reaction with increase in reactivity. Although the coke consumption by the solution loss reaction increases, the solution loss reaction in the central part of the coke particle is suppressed by the increase in coke chemical reactivity.
