Design, fabrication and testing of a machine for shelling Jatropha curcas seed

Abstract

Jatropha curcas is a non-edible drought-resistant seed rich in oil. The seeds are usually shelled to obtain the kernels prior to the oil extraction. This research was undertaken to design, fabricate and evaluate a sheller for jatropha seed at different moisture contents. The moisture content of the seed was varied in the range of 6.8−12.2% (wb) and the machine performance was evaluated. Empirical relationships between the machine performance and the moisture content were established. The results showed that the shelling and machine efficiencies decreased with an increase in the moisture content. A quadratic relationship was established between the cleaning efficiency and the moisture content of the seed. The data obtained are found to fit the established equations with 65% R sq. value, and so can be used for predicting the machine performance within the specified moisture range. The power required to shell the seed was found to be 1 HP, and the technology was affordable compared to the ones reported in the previous designs. The machine can therefore be used for Jatropha curcas seed shelling at different moisture contents.