Numerical simulation of pulverized coal combustion in the raceway of an oxygen blast furnace

The technological characteristics of a top gas recycling-oxygen blast furnace determine that in comparison with a traditional blast furnace the combustion condition of pulverized coal in the raceway has great changes. A mathematical model of pulverized coal flow and combustion in the blowpipe-tuyere-raceway bottom is developed in this paper. The influences of entry modes,oxygen enrichment,recycling gas temperature,H₂O and CO₂ contents on the burnout of pulverized coal are investigated by this model. The results indicate that an entry mode with the premixing of recycling gas and oxygen is obviously better than two other modes with recycling gas and oxygen entering alone. When the oxygen content changes from 80% to 90% the coal burnout increases from 87.525% to 93.402%. The effect of recycling gas temperature is not significant. The maximum gas temperature along the tuyere axis decreases by 124 K with the increasing of H₂O content in the recycling gas by 5%,and it drops by 113 K for CO₂.