Ability to reduce iron with additional hydrogen introduced into the blast-furnace natural gas stream

Abstract

Equations are obtained, calculations are made on them, and graphs of the temperature dependence of the extremely high degree of hydrogen utilization are presented, which characterize the reduction of iron under conditions when H2O moves from the zone of transformation of FeO into Fe to the zone of transformation of Fe3O4 into FeO and further from the zones of development of these two reactions to the zone of transformation Fe2O3 to Fe3O4 with decreasing amount of hydrogen. Under the blast furnace conditions, the limit value for the hydrogen use is 55–57 %. In the course of studies at a blast furnace with a useful volume of 1370 m3 at PJSC MMK, an increase in the ratio of the amounts of hydrogen supplied with natural gas and oxygen supplied with enriched air blast was accompanied by an increase in the degree of hydrogen use from 47.0 to 50.6 % and a decrease in specific coke consumption from 404.0 to 397.4 kg/t of pig iron. The ratio of specific consumption of coke and total hydrogen of natural gas in the form of hydrocarbons decreased from 1.41 to 1.29 kg/m3. In another series, a rational mode was revealed, characterized by an increased reactivity of coke and a reduced consumption of natural gas, the transition to which reduced the specific consumption of coke from 426.4 to 423.3 kg/t of pig iron. Under current conditions at PJSC MMK, a reduction in the specific consumption of coke by 50 kg/t of pig iron is possible with the consumption of additional hydrogen in the amount of 156 m3/t of pig iron by it introducing into the existing pipeline of natural gas.The article was prepared with the support of the grant of the President of the Russian Federation No. MD-1064.2022.4.