摘要
以辊式布料的单滚筒干燥机为对象进行南瓜浆滚筒干燥试验,探讨了滚筒干燥过程中物料的干燥动力学特性及其干燥动力学模型。根据物料的状态将滚筒干燥过程分为浆状和膜状两个阶段,测定了不同蒸气压力下物料的含水率,分析了干燥速率随蒸气压力和时间的变化规律。结果表明:物料中的水分大部分在浆状区中蒸发,蒸气压力越高,干燥速率越快;物料在膜状区中为降速干燥阶段,蒸气压力越高膜状区起始含水率越低,起始阶段的干燥速率越慢,干燥速率下降也越慢,干燥时间越短。膜状区物料含水率的试验数据与主要薄层干燥模型进行拟合,Midilli-Kucuk模型可以很好地预测南瓜浆滚筒干燥的动力学特性。
Drum drying characteristics of pumpkin pulp were investigated by using a single drum dryer with applicator rolls.The drum drying process was divided into two phases： pulp phase and flake phase.Under these two conditions,moisture content of the samples under different steam pressures was measured in order to analyze the relationship of the drying rate with the inner pressure and drying time.It indicated from the results that,most of the moisture evaporated during the pulp phase.The higher the steam pressure was,the higher the drying rate became.It was also shown that during the flake phase,only falling rate period was taken place.As the steam pressure increased,on one hand,the initial moisture content of flake phase became less and the drying rate became decreased,on the other hand,the decreasing of the drying rate was slow down and the drying time was much shorter.The experimental moisture loss data were fitted with 10 thin-layer drying models.Consequently,of all the drying models,a semi-theoretical Midilli-Kucuk model was fitted best.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2012年第4期126-131,共6页
Transactions of the Chinese Society for Agricultural Machinery
基金
科研院所技术开发研究专项资金资助项目(2010EG119164)
