For the sake of reduction of reducing agent in blast furnace, the use of ferro coke containing metallic iron as a catalyst was proposed to control the thermal reserve zone temperature. To produce ferro coke, the vertical type of coke oven is used to realize the optimum carbonizing process. In the vertical type coke oven, it is estimated that each particle has a specific residence time derived from the friction effect to wall and the interaction of particles. These phenomena have a great influence on the properties of ferro coke. In this study, the observation of descending behavior in the packed bed was carried out with cold model. The movements of descending particles were analyzed with DEM calculation for cold model and pilot plant. It was found that the friction effect between wall and particles caused the delay of descending speed on the corner of the furnace. Moreover, the mixing effect of particles during descending was studied with the application of diffusion model, using DEM calculation. The residence time distribution model for the vertical type coke oven was newly developed. On the basis of these results, the descending behavior in the pilot plant was clarified.
