Abstract:

Based on one dimensional hydrodynamics and reaction controlled un-reacted shrinking core model, a mathematical model was developed to predict the reduction behavior of iron ore fines in a circulating fluidized bed(CFB)reactor.The size distribution characteristics of the ore fines were considered in the model, and both gas phase and solid phase conversions were involved.The calculated results were in good agreement with the experimental data reported in the reference.The influence of gas velocity, gas composition, and circulation ratio on the reduction performance was investigated in an industrial scale CFB reactor.The results showed that solid phase conversion rate increased to different degrees with the increase of gas velocity and decrease of degree of oxidation of reducing gas.But increasing gas velocity could decrease gas phase conversion rate while decreasing degree of oxidation could increase gas phase conversion rate.The degrees of reduction for particles of different sizes became more even with a proper circulation ratio.