钢带烧结料层的干燥氧化过程仿真

针对钢带烧结机内铬铁球团的干燥氧化过程，建立一套多尺度的欧拉-欧拉双流体数学模型. 基于收缩核模型计算单个球团的物理化学反应，模型预测结果与现场数据吻合.结果发现生球层的干燥可以分为两阶段:不均匀升速干燥阶段和降速干燥阶段. 在生球层底部，第二干燥阶段会出现干燥速率又升高的现象，此时湿核表面温度为383K. 而当湿核半径小于4.75mm后干燥速率又开始下降. 过湿区的最大水分质量分数为10.2%，比初始值高7.4%. 当铬铁球团的温度达到焦炭的燃点后，焦炭的氧化优先于磁铁矿. 生球层在烧结区出口的平均温度达到1698K，满足生产需求.

Simulation of Drying and Oxidation Process of Pellets Layers in Steel Belt Sintering

A multi-scale Eulerian-Eulerian mathematical model was developed to study the drying and coke-magnetite oxidation process of ferrochrome pellets in a steel belt sintering machine. Physicochemical reactions of an individual pellet were calculated by the shrinking core model. The predictions were in reasonable agreement with the industrial data. The results showed that the drying of green pellets can be divided into two stages: the uneven increasing-rate and the falling-rate drying stages. However， in the latter stage， it was also observed that the drying rate increased gradually at the bottom of green pellets when the surface temperature of the wet bulb was higher than 383K. It decreased again after the radius of the wet bulb was smaller than 4.75mm. The maximum weight percent of the moisture in green pellets was 10.2%， which was 7.4% higher than the initial one. When the temperature of ferrochrome pellets reached the coke ignition， the coke oxidation had precedence over the magnetite oxidation. The average sintering temperature of green pellets was 1698K at the outlet of the sintering zone， meeting the process requirements.