Optimization of Intermittent Drying of Rehydrated Dates

Year 2025, Volume: 28 Issue: 2, 59 - 68, 01.06.2025

Issam Hasrane , Abdelouahab Benseddik , Boubekri Abdelghani , Djamel Daoud , Salah Bouhoun , Mohammed Abdelbassit Kherrafi , Ahmed Badji , Chihabeddine Nettari

https://doi.org/10.5541/ijot.1627719

Abstract

The intermittent drying of dates remains a neglected area in academic research, primarily due to factors such as varying cultivation patterns across regions and limited attention to the valorization of overdried dates. This study investigates the impact of drying parameters: air temperature, air velocity, and intermittency ratio, on the drying time and energy consumption of rehydrated dates using hot air drying. Employing Response Surface Methodology with a Central Composite Design and a desirability function, experiments were conducted within specific ranges of air temperatures (40–70 °C), air velocities (0.5–5 m/s), and intermittency ratios (0.2–1). Results show that while air velocity minimally affects drying time, it negatively influences energy efficiency. Conversely, air temperature is significant for both responses. Reducing the intermittency ratio from 1 to 0.3 resulted in a decrease in total energy consumption by up to 60%, particularly at lower temperatures, with negligible impact on total drying time. The study identifies optimal conditions for minimizing both drying time and energy consumption as an inlet temperature of 66 °C, air velocity of 2.5 m/s, and an intermittency ratio of 0.7. The experimental data were fitted to 7 mathematical drying models, the results indicated that Midilli-Kucuk model gave better performance to define the drying kinetics of intermittent drying of rehydrated dates.

Keywords

Intermittent drying , hot air dryer , response surface methodology , rehydrated dates

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