高炉热储备区温度对煤气利用率的影响

研究了高炉热储备区内温度与煤气利用率的关系.结合热力学和实际情况，热储备区内只发生氧化亚铁的还原.因此需要利用吉布斯自由能计算和单界面未反应核模型对热储备区内还原反应进行热力学和动力学分析.结果表明:只有在H₂+H₂O体积分数小于0.3时降低热储备区温度才能提高煤气利用率.从1273K降温到1223K，氢气还原速率降低得比CO还原速率降低得多，说明温度对氢气还原的影响更大.对一般高炉来说，炉料在热储备区中还原所需的时间比其停留时间长或接近，说明热储备区内的还原反应没有达到平衡，降低温度不利于提高煤气利用率.

Influence of Thermal Reserve Zone Temperature in Blast Furnace on Gas Utilization Rate

The relationship between temperature of thermal reserve zone and the gas utilization rate of blast furnace was investigated. Considering thermodynamics and practical condition， only the reduction of ferrous oxide occurs in the thermal reserve zone. Thus， the thermodynamic analysis and kinetic analysis of reduction reactions in thermal reserve zone were carried out with standard Gibbs free energy calculation and unreacted shrinking core model， respectively. The results of thermodynamic analysis show that only when the (H₂+H₂O) volume fraction is smaller than 0.3， lowering temperature is effective for improving gas utilization. The kinetic analysis shows that decreasing temperature from 1273K to 1223K， the reduction rate with H₂ decreases more than that with CO， showing that the influence of temperature on the reduction with H₂ is greater than that with CO. For most blast furnaces， the required reduction time is somewhat longer than the burden residence time in the thermal reserve zone， which means that the reduction reactions in thermal reserve zone don’t attain their equilibria， and lowering temperature is not effective for improving gas utilization.