Urea Hardness Optimization in a Fluidized Bed Coating Equipment Using Taguchi Design Method

This paper describes the use of Taguchi Method in optimizing coating hardness in a tangential fluidized bed coater using modified biopolymer. During the coating process, granular ureas collide among themselves and the wall surface at high velocity. This led to excessive attrition and likely to break the granular ureas into smaller sizes. Hence, hardness is the critical properties during operations such as packaging and stacking. A series of coating experiments were carried out by using the L9 orthogonal array with 3 levels to determine the effect of inlet air temperature (40, 60 and 80OC), disc rotation speed (40, 60 and 80 rpm) and spraying rate (0.5, 1.0 and 2.0 rpm) on hardness of coated granular urea. The optimized operating parameters in this work were 60OC for inlet air temperature, 60 rpm for disc rotation speed and 2 rpm for spraying rate. The results show that the spraying rate was the most significant factor affecting the hardness of the coated granular urea since the contribution was 69.2 %. No confirmations run for this work were necessary since the optimized operating parameters that were discovered was one of the experiments operating parameters.