Reduction of carbon rate in blast furnace by using catalyst doped nut coke

Abstract

The gasification characteristics of metallurgical coke plays an important role in controlling the thermal balance of blast furnace. In this work, the gasification reaction kinetics of nut coke was enhanced using catalytic materials to improve the reaction efficiency of blast furnace. The starting temperature of nut coke gasification was reduced by 100 °C using the solid waste materials (lime fines and iron oxide dust) that are generated internally from an integrated steel plant. Analysis of catalyst doped nut coke showed that the coke reactivity index (CRI) improved by 5–6 points over the normal nut coke. The catalyst doping facility with catalyst slurry preparation tank, slurry transfer pump, basket filter and spray header fitted with nozzles was developed to produce the catalyst doped nut coke on large scale. The plant trial was conducted in a commercial blast furnace for a month-long duration by replacing the normal nut coke with catalyst doped nut coke. As a result, the reduction of 4 kg carbon rate per ton of hot metal production was achieved through this methodology. Also, slight improvement was observed in the gas utilization efficiency of blast furnace when catalyst doped nut coke was used.