Design and development of a palm kernel nut cracking unit

Abstract

The object of this research is the cracking of the nuts of oil palm (Elaesis guineensis). The oil palm tree is one of the greatest economic assets a nation can have, provided its importance is realized and fully harnessed. After the oil extraction of palm oil from the palm fruits, virtually all methods involved in palm kernel nut cracking both in traditional and small-scale exist in scattered or separate units of operations. Hence, this research focused on designing a palm nut kernel cracking unit incorporating a separator in form of a screen to separate cracked palm kernel nut shell from kernel. The result shows that there were significant difference (p≤0.05) among the moisture content of the palm nuts, shaft speed of the machine and weight (feed rate), having a significant difference between: – moisture content of the palm nut and the shaft speed of the cracker; – moisture content and feed rate; – shaft speed and feed rate. There exist interaction between cracked, uncracked shell, damaged, undamaged kernel, and palm kernel nut breakage ratio. While, there was no significant difference among interaction between moisture content, shaft speed and feed weight. The result also indicated that for the highest speed of 1,800 rpm at a feed rate of 700 kg/h for all moisture contents, the cracking efficiency was between10 to 90 %, which implies that the kernel cracking efficiency increases with an increase in machine speed. However, it was observed that higher cracking efficiency was at the cost of higher kernel damage for all cracking speeds and feed rates, which is a problem. The kernel breakage ratio ranged from 1.040–7.85 for all feed rates and moisture contents. The kernel breakage ratio increased with moisture content and cracking speed but decreases with feed rate weight.