桃渣真空干燥特性数学建模

Mathematical Modeling for Vacuum Drying Characteristics of Peach Pomace

摘要:

为了探究干燥模型在真空干燥中的应用，试验以桃渣在不同真空干燥温度（55、65、75和85 ℃）下的干燥过程为研究对象，利用10种薄层干燥模型对其干燥特性曲线进行拟合分析，并计算其有效水分扩散系数和活化能。结果表明：干燥温度对桃渣干燥速率的影响较大，干燥时间随着干燥温度的升高而减少；桃渣干燥的主要阶段发生在降速干燥阶段。通过对文中10种薄层干燥模型的拟合结果进行对比可以发现，Wang and singh模型对桃渣干燥的拟合性较好（R2>0.99776），模型的预测值与试验值能较好吻合，适合描述桃渣在所有干燥条件下的干燥特性；根据费克第二定律获得桃渣真空干燥的有效水分扩散系数范围为8.0855×10-10~1.5340×10-9 m2/s，且随干燥温度的升高而增大；利用阿伦尼乌斯方程计算桃渣真空干燥的活化能为21.1 kJ/mol。本研究为真空干燥技术应用于桃渣的干燥提供了理论基础。

Abstract:

The drying characteristics, effective moisture diffusivity (Deff) and activation energy (Ea) of peach pomace with vacuum drying at 55 ℃, 65 ℃, 70 ℃ and 80 ℃ were investigated in this study. The experimental data obtained were fitted to ten thin-layer drying models. The results indicated that drying temperature had a significant influence on the drying rate of peach pomace. The drying time decreased with the increasing drying temperature, and the drying process appeared in the falling rate periods. Compared the results of ten thin-layer drying models, models of Wang and singh were the best to describe the drying process of peach pomace under all drying conditions (R2 > 0.99776), and there was a good agreement between the experimental and predicted values. According to the Fick’s second law, the values of effective moisture diffusivity varied from 8.0855×10-10~1.5340×10-9 m2/s. The relationship between the effective moisture diffusivity and drying temperature could be described by Arrhenius-type relationship, which resulted in activation energy of 21.1 kJ/mol for peach pomace. This study provides a theoretical basis for the application of vacuum drying technology in the drying of peach pomace.