Comparison of Drying Parameter Optimization of Lemon Grass

Submitted: Jul 22, 2013; Accepted: Sep 2, 2013; Published: Sep 11, 2013 Abstract: The purpose of this study is to determine the optimum condition of humidity contents, drying rate and energy in the experiment of drying of lemon grass in the fluidized bed dryer with presence of inert particles. The studied drying parameters were temperature, air velocity, mass of sand and drying time. The optimization methods used in the studies were Taguchi, Pareto, ANOVA, XLSTAT and DesignExpert. Design of experiment (DOE) used in this study was three levels and three factors (3L3F) where L orthogonal array was implemented. 27 DOE of three levels and four factors (3L4F) was applied for the optimization to observe the effect of drying time which implemented L orthogonal array. The temperatures were varied at 40°C, 50°C, 60°C; the air velocities 81 were ranged at 0.61 m/s, 0.73 m/s, 0.85 m/s; mass of sand as an inert particle used in the experiment were 0 g, 50 g and 100g. Lastly, the drying time was conducted at 10 min, 20 min and 30 min. In optimization process, Taguchi and Pareto ANOVA are the most appropriate statistical method to optimize the data due to its simplicity and no ANOVA table involved. For DOE of 3L3F, the optimum value of humidity contents was 0.0658 g/g aq which occurred at temperature of 60°C, air velocity of 0.85 m/s and 100g of sand. The optimum value of drying rate was 0.2497 g/g min which occurred at temperature of 50°C, air velocity of 0.85 m/s and 50 g of sand. Finally the optimum value of energy occurred at temperature of 40°C, air velocity of 0.61 m/s and 100 g of sand.