Study on Microwave Drying Characteristic for PET Materials

In this paper, we studied characteristics of material PET (Polyethylene terephthalate) by the microwave vacuum drying technology, which was performed in a resonant cavity. The test was conducted in -92 kPa to study the relation between power, drying time and moisture content for low moisture content substance during the process of microwave vacuum deep drying. Using moisture tester, moisture content of sample was determined during drying. In vacuum, microwave drying time is restricted to 1 hour. Results shows drying PET with microwave is easy to cause thermal runaway. After a lot of experiments, the lowest moisture content of PET reached 0.01% by microwave when the energy consumption only 1 kWh and drying time is only 30 min for 2 kg PET sample. There is a balance between power and efficiency in this experiment, which provided data for industrial application of microwave energy in drying PET.