Numerical Modeling of Reaction and Flow Characteristics in a Blast Furnace with Consideration of Layered Burden

Abstract

A blast furnace is modeled as a counter-current bed reactor filled with solid particles of coke and ore where the gas flows upward through the porous media while the bed material moves slowly in the counter-current direction of the gas flow. An axi-symmetric two-dimensional steady state model is proposed to simulate the gas and the solid flow, where thermo-chemical reactions and heat transfer process are considered. It is assumed that two phases of solid and gas exist in the furnace. The charged material is treated as porous media constructed by alternative coke and ore layers, which have different permeability. The internal gas flow of the furnace is governed principally by burden distribution. For understanding of the influence of the burden distribution on the internal situation, the entire layer structure is predicted from the measured top layer structure and the solid flow is assumed as the potential flow. Using this burden distribution, the flow, energy, and chemical species conservation equations are derived for each phase. In addition, the phase mass generation/consumption caused by reactions, heat transfer between gas and solid phases, and the reaction heat are reflected in source terms in the governing equations. For several different L_o/L_c (layer thickness ratio of ore and coke layer) cases, layer structures are constructed and numerical simulations are conducted. The finite volume method was used for the numerical simulations. Through this approach, the flow, composition and temperature distributions within the furnace are numerically predicted.