A Six-phases 3-D Model to Study Simultaneous Injection of High Rates of Pulverized Coal and Charcoal into the Blast Furnace with Oxygen Enrichment

Abstract

Simultaneous injection of charcoal and coal with oxygen enrichment in the blast furnace has recently received remarkable attention due to its possibility of considerable decrease in coke rate, increase in productivity and enhancement of combustion in the raceway. This paper deals with a modeling of simultaneous injection of pulverized coal and charcoal into the blast furnace through tuyeres. This model treats the blast furnace as a multi-phase reactor and six phases are considered simultaneously: gas, lump solids (raw iron ore, sinter, pellets and coke), hot metal, molten slag, pulverized charcoal and coal. Conservation equations for mass, momentum, energy and chemical species are solved simultaneously based on the finite volume method. Firstly two base cases of 200 kg/thm injection of pulverized coal and charcoal respectively are simulated and afterwards mixed injection of coal and charcoal are investigated. Simulation results for the two base cases are compared with measurements on industrial scale trials. Good agreement obtained for major operational parameters and inner temperatures verifies the model developed useful. Afterwards, the simultaneous injection operations are simulated in order to improve blast furnace performance. The simulation results contribute to better understanding of the blast furnace phenomena with combined injection and also to the development of new cleaner technologies to enhance the blast furnace operation.