过热蒸汽干燥传热传质特性的理论分析与试验

Theoretical Analysis and Experiment of Heat and Mass Transfer Process in Superheated Steam Drying

在系统分析过热蒸汽干燥过程的基础上,建立了简化的干燥数学模型,从传热传质角度对过热蒸汽的干燥机理进行了理论分析,并与热空气干燥进行了对比,最后通过稻米的过热蒸汽干燥试验验证分析结论。研究结果表明:提高过热蒸汽的温度以提高干燥介质与物料之间温度梯度,以及增加过热蒸汽的流速(流量)以减少传质阻力,可以显著提高过热蒸汽的干燥效率。

A simplified numerical model has been developed to study the characteristics of superheated steam drying based on the comprehensive analysis of superheated steam drying,and the theoretical analysis of the drying mechanism has also been completed from the standpoint of heat and mass transportation in comparison with hot air drying. The final analysis conclusion has been verified by means of the rice drying with Superheated Steam. The results indicate that the drying rate of superheated steam will be remarkably improved by increasing the temperature gradient between the material and drying medium,and by decreasing mass transfer resistance with the method of raising the flow rate of the superheated steam.