磁铁矿球团干燥过程动力学

Kinetics of Magnetite Pellets in Drying Process

采用热重分析实验技术,在氮气流下,100—300℃温度区间,不同的气流速度范围研究了磁铁矿生球团干燥过程动力学。实验表明,干燥过程可分为增速、恒速、减速(一)和减速(二)4个阶段。生球中绝大部分水分是在前3个阶段中脱除的,在热量和质量传递过程同时进行的理论分析基础上,对前3个阶段建立了统一的干燥过程动力学模型。由实验数据求得了模型中参数或表达式。应用此模型对球团干燥过程进行模拟计算的结果与实验测定结果相当符合,证明了本动力学模型的适用性。

The kinetics of green magnetite pellets in drying process was investigated by means of thermogravimetry, using nitrogen gas flow at different velocities in a temperature range from 100 to 300 @. Experimental results showed that the whole drying process goes through with its function in four steps,i.e., accele ration,constant,deceleration I and Ⅱ .Moisture in green pellets are mostly removed during the first three steps.A unified kinetic model of drying process is developed for the first three steps, based on a theoretical analysis in which both the heat transfer and mass transfer processes go on simultaneously. Parameters and expressions of the model are derived and given from experimental data.Calculation results by the model are found quite in agreement with those measured thus testifying its applicability.