Development and Performance of a Jatropha Seed Shelling Machine Based on Seed Moisture Content

Purpose: The high energy requirement of extraction of oil from jatropha seed and reduction of loss in oil content between whole seed and kernel of jatropha necessitate seed shelling. The purpose of this study is to develop and evaluate the performance of a jatropha seed shelling machine based on seed moisture content. Methods: A shelling machine was designed and constructed for jatropha seed. The components are frame, hopper, shelling chamber, concave, and blower with discharge units. The performance evaluation of the machine was carried out by determining parameters such as percentage of whole kernel recovered, percentage of broken kernel recovered, percentage of partially shelled seed, percentage of unshelled seed, machine capacity, machine efficiency, and shelling efficiency. All of the parameters were evaluated at five different moisture levels: 8.00%, 9.37%, 10.77%, 12.21%, and 13.68% w.b.). Results: The shelling efficiency of the machine increased with increase in seed moisture content; the percentage of whole kernel recovered and percentage of partially shelled seed decreased with increase in moisture content; and percentage of broken kernel, machine efficiency, and percentage of unshelled seed followed a sinusoidal trend with moisture content variation. Conclusion: The best operating condition for the shelling machine was at a moisture content of 8.00% w.b., at which the maximum percentage of whole kernel recovered was 23.23% at a shelling efficiency of 73.95%.