罐式还原的数值模拟

Numerical simulation for the process of cylinder-type reduction

本文建立反应罐径向一维非稳态数学模型,它包括多孔介质热量传递方程、多孔介质质量传递方程、多相化学反应速率方程和理想气体状态方程,利用该模型对整个实验过程进行模拟.通过实验数据和模拟数据的比较,可以得出该模型能较准确的描述反应罐直接还原的实验过程,得出半焦层中碳的化学反应热与导热量属于一个数量级,化学反应与多孔介质传热共同决定了还原反应速率.靠近半焦粉层的铁矿还原度较高,而靠近铁矿层中心其还原度较低,呈现"U"字分布.

A non - isothermal mathematical model was established which consists of the heat transfer equation within a porous medium, the mixed gas mass transfer equation, and the state of ideal gas equation to simulate the whole cylinder-type reaction process of the reduction of iron ore. By comparing the experimental data with the simulation data, it is shown that the model can accurately describe the reaction process of the direct reduction reactive cylinder. The reaction heat released by the reaction of carbon and heat conduction quantity is considerable in the semi-coke layer and the reduction reaction rate can be determined commonly by the chemical reaction and the porous medium heat transfer. The degree of iron ore reduction close to the coke layer is relatively higher and the reduction degree close to the center of iron ore layer is relatively lower,displaying a ＂U＂-shape distribution.