稻谷固定床式深层干燥试验研究

Drying Experiments of Paddy in a Deep Fixed-bed

以木板和通风板构建一台面积 2 2 .3 m2 的固定床干燥机 ,采用燃油直接燃烧加热的方式对谷物进行干燥。在不同的热风温度、稻谷初始含水率及总厚度条件下 ,测定了稻谷干燥的均匀性、各层稻谷的温升曲线和干燥曲线 ,分析了干燥参数对干燥床性能的影响。研究表明 :沿层厚方向存在显著的温度梯度 ,干燥逐层进行。热风温度越高、总厚度越大 ,分层干燥现象越明显。在定风量的条件下 ,热风温度对干燥的热量消耗无明显影响 ;总厚度增加、稻谷初始含水率降低 ,干燥的热量消耗呈降低趋势。

Paddy with various initial moisture contents were dried by a fixed-bed dryer with drying area 22.3 m2, that was made of boards, ventilating planks and a burner etc. under the conditions of different heat air temperatures and layer thicknesses. The temperature and moisture content of the paddy at different layer thickness were tested during paddy drying to investigate the relationships between temperature and moisture content of paddy and drying time. The results showed that there were distinct temperature and moisture content gradients along the layer thickness of paddy. Furthermore, the more the temperature and the layer thickness were, the larger the gradients. In the case of a deep layer thickness, it was impossible to dry the paddy at the surface completely. In addition, in the condition of a fixed heat air volume, the temperature of heat air had not distinct influence on the heat consumption, however the heat consumption had trend to fall down with the increase of layer thickness and decrease of initial moisture content of paddy.