Reduction of the distribution of the temperature field at flexible microwave drying of plant raw materials

Abstract

It has been established that the flexible possibilities of microwave technology are used in the processing of plant materials in the following technological processes: drying, reduction of microbial contamination (disinfection), production of juices and extraction. The spread of the high-frequency method of heating is explained by a number of its flexible features. First of all, with high-frequency heating, it becomes possible to ensure high rates of temperature increase in the material. The article discusses the ability to perform selective heating when processing inhomogeneous materials, reduces the energy costs of the process as a whole. It is established that the use of microwave technology makes it possible to obtain a finished product of higher quality and nutritional value. When drying due to a decrease in the loss factor of the material is heated, the rate of temperature rise automatically decreases until the end of the process, while reducing the possibility of unacceptable overheating of the product. Technological processes using high-speed high-frequency heating are easy to mechanize and automate. The introduction of the high-frequency method of heating significantly improves sanitary and hygienic working conditions, but a certain disadvantage of the EMF briquetting technology is the urgent need to shield the EMF only in the zone of interaction between the field and the substance and prevent its leakage beyond the maximum permissible levels. With rational selection of the frequency of oscillations and parameters of the chambers, where the conversion of microwave energy into heat takes place, it is possible to obtain a relatively uniform heat release throughout the body.