INFLUENCE OF THE PRESENCE OF LIFTERS IN THE DESIGN OF A ROTARY COCOA BEAN DRYER
Keywords:
Cocoa Beans, Design Parameters, Operating Parameters, Lifters, Rotary Dryer, Residence TimeAbstract
In practice, the presence of lifters in the drum of the rotary dryer plays an essential role in continuously stirring the cocoa beans, thus facilitating the drying of both the beans forming a curtain and the bed; three-dimensional lifters were used. The results show that the optimal unloading angle range obtained for better filling rate is between 110° - 140°. The effects of the operating parameters (the speed and temperature of the drying air, the ratios of the drying mass flow rates and the rotation speed) showed that the air speed of 0.5 m/s corresponds to an optimal reduction in water content, at the highest product temperature and drying kinetics. On the other hand, the appropriate air speeds are of the order of 1.5 m/s to 2.0 m/s, allowing us to consider the aesthetic aspect of the device. However, the impact of the design parameters (the inclination of the drum and the presence of the lifters) on the evolution of drying are of two orders: the first is that the entry speed of the cocoa bean particles increases once fallen from the flight. The second is that the inlet velocity in the axial direction increases, as does the velocity in the transverse direction, resulting in a reduction in dwell time. Complemented to this, the addition of the lifters in steps of 5 caused a further 12% reduction in the water content. Finally, the optimization results revealed the tilt angle of 3°, the diameter of 0.6 m, and the rotation speed of 10 rpm of the drum and the characteristic lengths of the lifters of 0.125 m, 0.125 m and 0.50 m as the optimal operating sizes of the rotary cocoa bean dryer.
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Copyright (c) 2024 TAKOUDJOU FOSSI Corneille Roosvel, NGNASSI DJAMI Aslain Brisco, DJEUMAKO Bonaventure, EDOUN Marcel (Author)
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