Effect of desiccant system on thin layer drying kinetics of corn.

Drying is one of the most important post-harvest processes for reducing the moisture content of agricultural products and improving their performance has obvious benefits. Most dryers are convective type in which hot air is used for reduction of product moisture content. Effect of adding a desiccant unit to a re-circulating convective dryer on thin layer drying kinetics of corn kernels is reported here. The influence of the desiccant unit, drying temperature and flow rate on drying time, moisture diffusivity coefficient and reactivation energy were investigated. The experiments were conducted at air temperatures of 50, 60 and 70 °C and flow rates of 1, 1.4 and 1.8 kg/min with and without the desiccant unit. Results showed that the use of the desiccant wheel decreased drying time by 9.75% and increased drying rate by 7.85%. Application of a Logarithmic model for fitting the data, while being simple, resulted in good statistical indexes (R2 and RMSE). Moisture diffusivity coefficient was obtained to be in the 3.47258 × 10-11 to 8.18826 × 10-11 m2/s range, while activation energy varied between 14.2931 and 17.6770 kJ/mol on the average. Therefore, utilization of the desiccant unit accelerates moisture extraction from corn samples.