炉顶煤气循环氧气高炉一维气固换热与反应动力学模型

结合风口回旋区燃烧和炉外煤气预热、脱除和循环的平衡关系,建立了氧气高炉一维气固换热与反应动力学模型,并采用传统高炉的运行和解剖数据对模型进行了验证分析.通过模型研究了氧气含量和上部循环煤气流量对氧气高炉炉内过程变量的影响规律.结果表明：氧气含量偏低和上部循环煤气流量不足时,会降低铁矿石还原效果,炉渣内出现大量未还原铁氧化物；氧气含量和上部循环煤气流量的提高可以有效提高炉内CO含量和铁矿石还原速度,但提高上部循环煤气流量会大幅提升炉顶煤气温度,增大热量损失.与传统高炉相比,氧气高炉内CO含量提高1.0~1.5倍,炉内气体还原性更强；铁矿石还原完成位置提高1.49 m,全炉还原反应速度更快；直接还原度降低55.2%~79.2%,炉内直接还原反应消耗的碳量更少.

One-dimensional mathematical model for oxygen blast furnaces with top gas recycling based on heat transfer and reaction kinetics

A one-dimensional mathematical model based on heat transfer and reaction kinetics was developed for an oxygen blast furnace and was validated with the operating conditions and dissected data of a conventional blast furnace. The influence of oxygen concentration and upper gas volume on the smooth operation and process variables of the oxygen blast furnace was investigated by the model combined with coal combustion at tuyeres and top gas balance for separation and preheating. When the oxygen blast furnace with top gas recycling is of low oxygen concentration and upper gas volume, the reduction of iron ore is worsen and massive unreduced iron oxide comes into slag. In the oxygen blast furnace with top gas recycling, oxygen concentration and upper gas volume have significant effect on the temperature, reducing ability of gas and reduction rate. A comparative analysis of the conventional blast furnace and the oxygen blast furnace with top gas recycling show that the oxygen blast furnace has a higher reducing ability of gas ( 1. 0 to 1. 5 times higher for CO content), faster reduction rate (1. 49 m higher for the position of ore reduction), and less direct reduction (55. 2% to 79. 2% less for direct reduction degree) .