The reduction of wustite with high oxygen enrichment and high injection of hydrogenous fuel

Abstract

In order to reduce CO2 emission and energy consumption in a blast furnace, It is necessary to investigate the effects of some factors on direct reduction from wustite (FeO) to iron(Fe) with high oxygen enrichment and high injection of hydrogenous fuel, such as the composition and temperature of reducing gas mixture and the water-gas shift reaction. The current experiments reveal: (1) Reducing power of gas mixture with low oxygen enrichment and high PCI injection Is limited, the reduction degree of wustite is 53.6% after 90 min at 1 000°C; While with high oxygen in blast (40%) and high natural gas Injection (about 15% H2 In hearth gas), the reduction degree reaches 100% after 64.81 min, In the case of reduction with pure oxygen and higher hydrogen, the reduction speed promotes further. At 900°C, 100% reduction needs 64min. (2) The utilization efficiency of hydrogen drops when H2 content is over 50% in the gas mixture without N2. The optimum value of H2 content for pure oxygen blast furnace Is between 15-30% from the point of view of wustite reduction. (3) The water-gas shift reaction counteracts wustite reduction in the case of gas mixture with high content of CO2 and H2 at elevated temperature. © 2007 ISIJ.