Numerical investigation of simultaneous injection of pulverized coal and natural gas with oxygen enrichment to the blast furnace

The multiple injection of carbonaceous materials and oxygen enrichment in the blast furnace has received especial attention in the recent years due to its possibility of considerably decrease in coke rate and increase of the productivity. This paper introduces a modeling of the co-injection of pulverized coal and natural gas into the blast furnace through the tuyere. This model treats the blast furnace as a multi-phase reactor and five phases are treated simultaneously: gas, lump solids (iron ore, sinter, pellets and coke), pig iron, molten slag and pulverized coal. Conservation equations for mass, momentum, energy and chemical species are solved simultaneously based on the finite volume method. Firstly pulverized coal is simulated and afterwards only natural gas is investigated and compared with the all coke operation. Finally, the combined practice is suggested in order to improve the actual blast furnace operation. The simulation results have contributed to better understanding the blast furnace phenomena with multiple injectants, and supported new improvements in the furnace operation. The results obtained in this investigation have shown the possibility of considerable advances in the actual blast furnace operation such as increase in productivity, lower silicon content in hot metal and decrease of the coke and slag rates. In addition, the total amount of the greenhouses in the off gas is decreased, which contributes to make the blast furnace process cleaner.