含炭塊成鉱および水素還元の適用による高炉排出CO₂の削減

抄録

The annual CO₂ emissions in Japan is approximately 1.1 Gt and the steel industry section accounts for its about 14%. The ratio of the blast furnace (BF) ironmaking process occupies about 70% of the emissions of the steel industry. Therefore, reduction of CO₂ emissions from the BF process is an important issue. In order to reduce CO₂ emissions from the BF, it is necessary to reduce its carbon consumption. Two plausible methods can be pointed out: One is the utilization of hydrogen as a reducing agent instead of carbon, and another is the improvement of the efficiency of CO gas reduction. It is effective to lower the reduction equilibrium point temperature of CO and CO₂ determined by the gasification start temperature of the carbonaceous materials for an increase in the efficiency of CO gas reduction. Utilization of the agglomerates prepared by the mixture of fine ore and fine coke, namely “Reactive Coke Agglomerate (RCA)” is also effective for a decrease in the reduction equilibrium point temperature.

The purpose of this study is to clarify the effect of RCA utilization on the thermal reserve zone temperature and reduction efficiency under hydrogen enriched conditions. A series of the evaluation experiments was conducted using the Blast-furnace Inner-reaction Simulator (BIS). The results show that the use of RCA gives the effect to reduce CO₂ emissions from the blast furnace in the range of H₂ concentration of Bosh gas up to 20%.