Drying of Prina Using Microwave Energy and Determination of Appropriate Thin Layer Drying Model

Abstract

This study examined the thin layer drying kinetics of the prina in the microwave. Prina samples with 7mm, 9mm and 11mm thickness were dried using 90, 180, 360 and 600 W (2450 MHz) microwave output powers and changing of moisture content of samples depend on time were determined. The drying rate increased with the increase in microwave power output. The final moisture content was determined at the end of 13250s for 90W, at the end of 1070s for 360W, at the end of 820s for 600W for prina of 7mm thickness, at the end of 17640s for 90W, at the end of 1360s for 360W, at the end of 990s for 600W for prina of 9mm thickness and at the end of 23440s for 90W, the end of 1580s for 360W, at the end of 1070s for 600W for prina of 11mm thickness in four different microwave powers. To evaluate the experimental data, Wang & Singh, Two Term, Two Term Exponential and Midilli et al. thin layer drying models suggested in the literature were used. Comparison between models was performed using the statistical parameters as R-2, X-2 and e(s). Among used the models, Two Term Exponential for 7mm, Midilli et al. for 9mm, Two Term for 11mm were found to be the best models representing the microwave drying behavior of prina samples. Also, according to modelling results, it was determined that the effective diffusion coefficient and activation energy changed between 1,17.10-5-4,11.10-6 m(2) s and 0,1190kj/mol-0.3577 kJ/mol, respectively.