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疏解棉秆在进行重组材之前,要进行干燥处理。本研究以疏解棉秆为研究对象,探讨了疏解棉秆在不同微波功率密度(8,10,13,20 W/g)和不同相对压力(0,-20,-40,-60,-80 kPa)时的干燥情况,研究了不同的微波功率密度和相对压力对疏解棉秆干燥特性的影响,通过建立动力学模型来预测疏解棉秆微波真空干燥过程中的水分变化。结果表明:当初始含水率大约为100%时,不同的微波强度下,干燥所需时间为9~16 min,明显少于同等条件下热风干燥时间;并且在干燥过程只有升速和降速两个阶段,没有明显恒速阶段;随着微波真空相对压力的降低,干燥速率增大,干燥时间缩短,但相对压力低于-60 kPa后继续降低压力对干燥速率影响不显著。疏解棉秆微波真空干燥的动力学模型满足Page方程,该模型可较好地描述疏解棉秆含水率随干燥时间、微波功率密度的变化关系。本研究可为实现疏解棉秆快速、高效的干燥以及品质保障提供新思路,为相关干燥设备的设计开发提供理论依据。
To ease the cotton stalk in the restructuring before the material to be dried. In this study, cotton stalks were studied to investigate the effects of cotton stalks at different microwave power densities (8, 10, 13, 20 W / g) and different relative pressures (0, -20, -40, -60, -80 kPa), the effect of different microwave power density and relative pressure on the drying characteristics of cotton stalk was studied. The dynamic model was used to predict the moisture change in the microwave vacuum drying process of cotton stalk. The results show that when the initial moisture content is about 100%, the drying time is 9-16 min under different microwave intensities, which is obviously less than the hot air drying time under the same conditions. In the drying process, As the relative pressure of microwave vacuum decreased, the drying rate increased and the drying time shortened. However, when the relative pressure was lower than -60 kPa, the pressure was decreased and the drying rate was not significantly affected. The kinetic model of microwave-assisted vacuum drying of cotton stalks satisfied the Page equation, which could describe the relationship between moisture content of cotton stalks and drying power and microwave power density. This study can provide a new idea for the quick and efficient drying and quality assurance of cotton stalk, and provide a theoretical basis for the design and development of related drying equipment.