Comprehensive Mathematical Model of Full Oxygen Blast Furnace with Top Recycle Gas Heated by Gasifier

Abstract

A comprehensive mathematical model of full oxygen blast furnace with top recycle gas heated by gasifier was established. The model consists of the calculation equations for gas composition of four zones (hearth, belly, lower shaft, top) in the blast furnace, the thermo-chemical balance model of blast furnace, the energy balance model of hot stand-by zone of blast furnace, the shaft efficiency model of blast furnace, the calculation equations for gas composition of gasifier and the thermo-chemical balance model of gasifier. By using this model, the new process was calculated. The results show that coke rate and coal rate of the new process are 200 kg/thm and 190 kg/thm respectively, fuel rate is decreased by 24.7% compared with that of conventional blast furnace. In addition, theoretical combustion temperature decreases with increasing hearth-recycle gas quantity. Increasing of hearth-recycle gas quantity by 10 m3/thm decreases theoretical combustion temperature by 11.6 K. Furthermore, the model could be applied to calculate the operating parameters when the raw materials and fuel conditions are different, and the changing laws of operating parameters under the same raw materials and fuel conditions could also be studied with this model.