Analysis of the combined injection of pulverized coal and charcoal into large blast furnaces

The simultaneous injection of pulverized coal and charcoal in the blast furnace has recently received remarkable attention due to its potential to decrease the coke consumption and increase productivity. This paper is focused on modeling the simultaneous injection of pulverized coal and charcoal into the blast furnace through the tuyeres with oxygen enrichment. This model treats the blast furnace as a multi-phase reactor and six phases are considered simultaneously, namely: gas, lump solids (lump iron ore, sinter, pellets, coke and small coke), hot metal, molten slag, pulverized coal and charcoal. Conservation equations of mass, momentum, energy and chemical species are solved simultaneously based on the finite volume method. The model is validated with a base case of actual operation using 215 kg/thm of pulverized coal injection and afterwards mixed injection of coal and charcoal are simulated for injection rate of 250 kg/thm. Model results indicated that the productivity of the blast furnace could be increased up to 25% with simultaneous injection combined with oxygen enrichment.