Numerical Analysis of Multiple Injection of Pulverized Coal, Prereduced lron Ore and Flux with Oxygen Enrichment to the Blast Furnace.

Abstract

This paper introduces a modeling of the co-injection of pulverized coal, pre-reduced iron ore and flux into the blast furnace through the tuyere. This model treats the blast furnace as a multi-phase reactor. The pulverized coal and pre-reduced fine ore/flux have different chemical and thermophysical properties, thus these materials are treated as separate phases. Therefore this model considers six phases: gas, lump solids (iron ore, sinter, pellets and coke), pig iron, molten slag, pulverized coal and pulverized iron ore/flux. Conservation equations for mass, momentum, energy and chemical species are solved simultaneously based on the finite volume approach. Two operational practices are investigated. One is the injection of pre-reduced fine iron ore and pulverized coal, and the other is the co-injection of pre-reduced fine ore, flux and pulverized coal. The simulation results have contributed to better understanding the blast furnace phenomena with multiple injectants, and supported new improvements in the blast furnace operation. With this model, the injection of pulverized iron ore and flux together with pulverized coal has been proved to be possible at high rates keeping stable blast furnace operation. Moreover, the silicon content can be lowered and the furnace productivity can be largely increased.