When microwave heating is applied to industrial chemical industry, under the high-frequency electromagnetic field impregnation, the polar molecules (water molecules) in the product receive microwave heat to generate heat, so that the product is rapidly heated and dried, and microwave drying is divided into 4 stages: internal adjustment, liquid flow, constant velocity drying and deceleration drying stage. Therefore, it is generally advisable to pre-empt the material in smaller granular or flake form to improve the drying outcome.
The focus of microwave drying equipment is the microwave generator, the frequency of microwave drying is mainly 2450 MHz, which is mostly used for drying in chemical, food, agricultural and sideline products, wood, building materials, paper products and other industries, and can also be used for the sterilization of food, agricultural and sideline products. Nowadays, there are many scientific research and production units engaged in the research and application of microwave technology in China's food industry, and new technologies and new processes are put into operation every year. First, the conventional tunnel drying equipment is mainly used for the drying of materials with low drying temperature requirements and no volatile substances in the process (it can be dried to 0.0% of the water content in a few to ten minutes, and the temperature can be controlled within 100 degrees; It is mainly used in the drying of heat-sensitive materials and the drying of volatile materials.
Due to the inevitable pressure formed by the heating and vaporization of water during the drying process, the cells can be quickly broken and the cell membrane can be fragmented, so the extraction process can be relatively shortened and can be effectively further improved.
Microwave drying principle: Microwave refers to electromagnetic waves with frequencies between 300 megahertz and 300 gigahertz. Because the frequency of the electromagnetic field is extremely high, the frequency of the vibration of polar molecules is very high, so the heat generated is high. Because the frequency of the electromagnetic field is extremely high, the frequency of the vibration of polar molecules is very high, so the heat generated is high. In the environment where the overall innovation of drying equipment is insufficient, microwave drying equipment leads the wind flow, and the prospect is promising.