S波段变频微波方腔干燥PET切片的研究

目的 针对聚对苯二甲酸乙二醇酯（PET）材料传统干燥方式能耗高、效率低等不足，运用微波干燥材料具有速度快、效率高、易于控制的特点，研究微波深度干燥PET技术并研制实验装置。方法 提出微波变频和变功率加热干燥技术，通过主动调整频率改善微波均匀性，结合微波变功率技术，控制PET材料温度在170～180℃，提升PET材料温度均匀性，并防止“热失控”现象的发生。结果 当干燥时间为2 h时，实现了PET深度干燥，能耗率为1.03 kW·h/kg，含水率降低至0.01%以下，达到了后续包装材料注塑加工的要求。结论 微波变频变功率加热技术适用于低含水率PET的深度干燥，比传统干燥方式能耗低并且时间短。

S-band Frequency-tuning Microwave Drying of PET Materials in a Cubic Cavity

Aiming at the shortcomings of the traditional drying method of polyethylene terephthalate (PET) materials such as high energy consumption and low efficiency, the work aims to study the technology of deep drying of PET by microwave and develop the experimental device based on the characteristics of high speed, high efficiency and easy control of drying materials by microwave. The microwave frequency-tuning and variable power drying technology was proposed, and the microwave uniformity was improved by actively adjusting the frequency. Combined with microwave variable power technology, the temperature of PET material was controlled at 170-180 °C, the temperature uniformity of PET material was improved and the occurrence of "thermal runaway" was prevented. When the drying time was 2 h, the deep drying of PET was realized, the energy consumption rate was 1.03 kW.h/kg, and the moisture content was reduced to less than 0.01%, which met the requirements of subsequent injection molding processing of packaging materials. Microwave frequency-tuning and variable power technology is suitable for deep drying of PET materials, which has advantages over traditional drying methods in terms of time and energy consumption.