Numerical analysis of the characteristics inside pre-reduction shaft furnace and its operation parameters optimization by using a three-dimensional full scale mathematical model

Abstract

Numerical simulation is considered to be an important method to study the inner characteristics of metallurgical processes, thus providing effective strategies for practical smooth operations. A three-dimensional full scale mathematical model considering mass, momentum, energy transfers and chemical reactions under steady state is developed in the present work to describe the characteristics inside the pre-reduction shaft furnace of COREX smelting reduction ironmaking process. The uneven gas and solid flow distributions in both radial and axial directions not only restrain the gas utilization but also cause the difference in the solid metallization between the center and near wall to reach as high as 0.4. Predicted by the established model, the CO-CO 2-H2-H2O reducing gas with the temperature 1 050-1 100 K, the volume fraction of CO+CO2 around 70%, the ratio of CO to CO2 5-7, as low as possible H2O content, and the reasonably matched burden solid charging rate to control the top gas consumption per ton burden solid (TGC) in the range of 800-1000 Nm3/t, are the optimal operation conditions to further improve furnace efficiency. © 2013 ISIJ.