油菜籽热风干燥传热传质与优化的研究进展

Research Progress of Heat and Mass Transfer and Optimization of Rapeseed Hot-air Drying

油菜是经济价值高、发展潜力大的油料作物,也是蛋白质、饲料、蜜源和能源作物,油菜籽的干燥和储存联系油菜高产栽培和油脂深加工综合利用。本文在分析油菜籽干燥特点和主要干燥技术的基础上,综述了油菜籽热风干燥传热传质与优化的研究进展,以期为油菜籽热风干燥装置设计、干燥工艺、参数和过程优化等的研究提供依据。目前,有关油菜籽热风干燥传热传质与优化的研究多限于实验层面,不具有广泛适用性。传统干燥理论和模型大多以Luikov理论和Whitaker理论为基础,对其适当简化或修正,由于假设多孔介质为均匀分布连续介质,无法揭示局部和整体之间的本质联系。将分形理论与孔道网络模型相结合是多孔介质干燥尺度综合的有效方法。数值研究有宏观、多尺度和微观三个层面,借助CFD技术可以有效获悉干燥速率、能量消耗和湿分分布等信息,以优化干燥装置和过程控制。油菜籽热风干燥实验研究主要集中在干燥特性、干燥品质及其测量技术等方面,为获得良好的干燥品质,应注意干燥工艺、参数和过程优化。

Rape is grown for production of vegetable oil, protein, forage, nectar, and energy with high economic value and development potential. The process of drying and storage of rapeseed is a key link between rape planting and oil comprehensive process and utilization. Based on analysis of rapeseed drying characteristics and main drying technology, research progress of heat and mass transfer and optimization of rapeseed hot-air drying was summarized for providing basis for optimization of apparatus design, drying technique, parameter, and process control. Traditional drying theories and models are mostly based on Luikov Theory and Whitaker Theory, and made some simplification or modification. Since porous media was assumed as meanly distributed continuous material, the intrinsic relationship between the local and the whole porous media is hard to be revealed. Combining Fractal Theory and Pore Networks Model is an effective method for scale integration of porous media drying. Numerical researches on hot-air drying are made from macroscopic, multiscale and microscopic perspectives. By applying CFD technology, information of drying rate, energy consumption and moisture distribution can be effectively obtained, which can be employed to optimize the drying apparatus and control the drying process. Researches on rapeseed hot-air drying are mainly focused on drying characteristics, quality of the product and their measurement technology. The drying technique, drying parameters and drying process should be optimized in order to obtain good drying quality of the product.