Article ID: ISIJINT-2019-058
A three-dimensional steady state mathematical model, considering the chemical reactions and the transfers of momentum, heat and mass between the gas and solid phases, is developed to investigate the performance of COREX central-gas-distribution (CGD) shaft furnace with top gas recycling (TGR). The model is validated first by data from practical measurement and then is used to study the performance of CGD shaft furnace with TGR. The results reveal that, compared with the process of 15% CGD gas input without TGR, the TGR can reduce the fresh gas consumption from 1058 Nm3/tBurden to 392 Nm3/tBurden. The reduction potential of top gas with TGR increases from 0.5755 to 0.6293, the utilization rate of top gas decreases from 34.18% to 28.03%, the metallization rate of solid product increases from 61.80% to 70.05%, and the standard deviation of metallization rate decreases from 0.8% to 0.4%.