Dielectric properties of peanut-hull pellets at microwave frequencies

Peanut-hull pellets are obtained from a waste product, peanut hulls, which after pelleting can have several uses, namely as a renewable fuel. Rapid and nondestructive characterization of peanut-hull pellets is important for industrial utilization of this resource. Properties such as moisture content and bulk density are important for quality control and pricing and control of the energy conversion process. The dielectric properties of peanut-hulls pellets can be used for the development of rapid and nondestructive sensors. In this study, the dielectric properties of peanut-hull pellets were measured at frequencies between 5 and 15 GHz, for moisture contents between 4% and 13%, temperatures between -15°C and 38°C, and bulk densities between 0.54 and 0.69 g·cm^-3.