Drying Rice Grain with Microwave in False Boiling Layer

Abstract

This study explores an innovative method for drying rice grains using microwave energy combined with a pseudo-boiling (fluidized) layer system. The proposed drying apparatus, developed at Namangan State Technical University, enables direct energy transfer to the rice core through the husk by means of electromagnetic waves. Experimental measurements were conducted to evaluate the distribution of the microwave field emitted from the magnetron, and theoretical models were formulated to calculate the drying time based on the physical properties of rice. The results demonstrate that microwave-assisted pseudo-boiling drying significantly reduces energy consumption and drying duration compared to traditional convection-based techniques. Furthermore, an analytical expression was derived to estimate the number of heating cycles required to raise grain temperature, taking into account electromagnetic background intensity and rice grain surface geometry approximated as an ellipsoid. The findings confirm the effectiveness of this method in improving drying efficiency and suggest potential for industrial-scale applications with minimal thermal damage to the rice.