摘要
利用热风干燥实验装置并采用130℃、150℃、170℃的风温及2m/s、3m/s的风速对碳化硅超细粉球团的干燥特性及干燥模型进行研究。结果表明:碳化硅超细粉球团的干燥过程分为三个阶段,即升速、恒速和降速阶段,其中升速阶段的干燥时间较短约为20～30min,恒速阶段的干燥时间约为50～80min,降速阶段的干燥时间约为180～210min;在碳化硅超细粉球团干燥的恒速阶段,干燥速率由高到低的顺序为:170℃>150℃>130℃,在降速阶段,风温170℃时干燥速率下降最快;当风速高于2m/s时,碳化硅超细粉球团的干燥速率变化不大。通过对在不同温度和不同风速条件下的碳化硅超细粉球团干燥的实验数据与8个常用的干燥模型进行拟合分析,发现修正Page模型(Ⅱ)干燥模型拟合度最好,可以较好地反映出碳化硅超细粉球团在不同温度和不同风速下的干燥特性。
This paper studied the drying characteristics and drying model of SiC ultrafine powder pellet under different temperatures(130℃,150℃ and 170℃) and different air velocities(2m/s and 3m/s) on experimental drying devices.The results show that the drying process of SiC ultrafine powder pellet is divided into three stages:rising speed stage,constant speed stage and falling speed stage.The drying time of the rising speed stage is about 20-30min;the drying time of the constant speed stage is about 50-80min;and the drying time of the falling speed stage is about 180-210min.The higher the hot air temperature,the higher the drying rate of the constant speed stage is and the larger the slope of the drying rate curve in the falling rate period is.When the wind speed is higher than 2m/s,the drying rate is not changing obviously.Through the analyses of the experimental data of drying SiC ultrafine powder pellet under different temperatures and velocities and the 8 frequently used fitting models,it is found that the goodness of fit of the modified Page model(Ⅱ) is the best and this model can reflects the drying characteristics of SiC ultrafine powder pellet under different temperatures and air velocities.
