皂荚籽热风干燥特性及干燥动力学模型研究

目的:为了研究皂荚籽干燥特性,为其机械化剥离应用提供理论参考。方法:研究了不同温度(70、90、110与130℃)与不同预处理方法(清水、碳酸氢钠溶液、焦磷酸二氢二钠溶液和酒石酸氢钾溶液浸泡)对皂荚籽干燥动力学的影响,使用Lewis模型、Page模型与Weibull分布函数对其干燥特性曲线进行非线性拟合并进行评价,并通过应面回归模型建立起干燥动力学模型。结果:皂荚籽干燥过程存在明显的升速降速段,且干燥温度越高,干燥速率越快,预处理方法对其干燥速率有一定影响。通过比较各模型的分别是决定系数()、卡方检验值()、残差平方和()与均方根误差(),结果显示Weibull分布函数能更好地模拟皂荚籽干燥过程,形状参数()随温度的升高而降低,尺寸参数()与预处理方法有关。计算了皂荚籽干燥过程的有效水分扩散系数()及其估算值()与活化能(),水分扩散系数及其估算值随着温度的升高而升高,经过酒石酸氢钠溶液预处理的皂荚籽的活化能低于其它预处理方法,可大大提高皂荚籽干燥效率。结论:经碳酸氢钠溶液预处理的皂荚籽干燥较容易发生,Weibull函数能较好地描述皂荚籽干燥过程中水分含量的变化规律,酒石酸氢钠溶液可以降低皂荚籽的活化能。该研究可为皂荚籽干燥提供理论和技术基础。

Hot air drying characteristics and drying kinetics model of Gleditsia sinensis seeds

Objective To study the drying characteristics of Gleditsia sinensis seeds, and provide theoretical references for its mechanized peeling application. Methods The effects of different temperatures (70, 90, 110, 130°C) and different pretreatment methods (soaking in water, sodium bicarbonate solution, dihydrogen diphosphate disodium solution and potassium bicarbonate solution) on the drying kinetics of Gleditsia sinensis seeds were studied. The Lewis model, Page model and Weibull distribution function were used to carry out nonlinear fitting and evaluation of the drying characteristic curves, and the effective moisture diffusion coefficient, its estimated value and activation energy of Gleditsia sinensis seeds during the drying process were calculated. The drying kinetics model was established by response surface regression model. Results In the drying process of Gleditsia sinensis seeds, the higher the drying temperature, the faster the drying rate, and the pretreatment method had certain influence on the drying rate. Weibull distribution function could better simulate the drying process of Gleditsia sinensis seeds. The effective moisture diffusion coefficient and its estimated value increased with the increase of temperature, and the activation energy of Gleditsia sinensis seeds pretreated with sodium bicarbonate solution was lower than that of other pretreatment methods, which could greatly improve the drying efficiency of Gleditsia sinensis seeds. Conclusion The drying of Gleditsia sinensis seeds pretreated with sodium bicarbonate solution is easier to occur, Weibull function can better describe the change rule of moisture content during the drying process of Gleditsia sinensis seeds, and sodium bicarbonate solution can reduce the activation energy of Gleditsia sinensis seeds. This study can provide theoretical and technical basis for the drying of Gleditsia sinensis seeds.