Experimental Verification of a New Technique for the Dry Separation of Palm Kernel and Shell Mixture

Abstract

Effective separation of the cracked palm nut mixture is an important process in the downstream utilisation of the constituent palm kernel and shell in some existing and emerging agro-economy. Whilst, the conventional wet separators are sophisticated and energy inefficient, the dry systems are at experimental stages and are inadequate for separating kernel and shell of comparable sizes. However, the difference in the path variables of particles of same size, but different shapes, in circular motion, suggests the possibility of separating the dry mixture in a rotating trammel with a co-axial spout. Based on the theory, the study investigated the dispatch angles for palm kernel and shell from a friction lining on the inner curved surface of drums of different diameters and rotating speeds. A built experimental facility allowed estimation of the dispatch angle for particles placed on the lining. The results show that palm kernels oscillate and move axially with the dispatch angle increasing with the drum diameter, but consistently less than 90o for the different diameters and speeds of the drum. The shells are dislodged at higher dispatch angles and in curvilinear trajectories away from the drum surface, causing a separation of the mixture. It is concluded that the experimental data are in good agreement with the theory and that the theory is sufficiently adequate for the determination of the design parameters of a proprietary separator.