Coke Size Degradation and Its Reactivity Across the Tuyere Regions in a Large-Scale Blast Furnace of Hyundai Steel

Abstract

It has been well recognized that coke samples can be effectively taken out of working blast furnaces using a drilling machine at the tuyere level. The core represents samples with different temperature profiles at various tuyere regions of a large blast furnace. The average coke size at the tuyere level is known to be about 50 pct smaller than the charged cokes. Using fixed bed reactor and XRD techniques, the cokes sampled were studied for CO2 reactivity and crystallinity, respectively. The apparent reaction rate of coke rapidly increases in the raceway zone, followed by a decrease as the samples are taken at deeper sites in the furnace where the Fe2O3 and CaO contents are high in the bosh and raceway zones in the high temperature regions. In this study, samples extracted at the tuyere level of a large blast furnace were examined to characterize the coke size degradation and the effect of coke graphitization on the reactivity and fines generation at various locations around the tuyere level.