Development of an integrated corn dryer with an indirect moisture measuring system

Abstract

Moisture sensors are used for real-time measurement of the moisture content of seeds in modern grain dryers. The electrical properties of grains are dependent on moisture content, density, temperature and structure of materials and also on the frequency of the applied electric field. In the study, a laboratory scale dryer integrated with capacitive sensor has been developed and modeled for shelled corn. The dielectric properties of shelled corn with different moisture content have been measured to find optimal working frequency. Modeling based on the relationship between the moisture content and electrical properties of corn have been done. Changes of moisture content affect the dielectric constant of the grain, which in turn makes variation in capacitance. The dielectric properties of corn have been measured at 1 MHz frequency value. The dielectric properties of corn have been characterized using the curve fitting technique. Corn drying experiments have been carried out in the laboratory scale test installation. Model accuracy has been verified by comparison with the results of drying tests.