Development and evaluation of a combined roaster expeller for castor seeds for biodiesel production

Abstract

A combined roaster and oil expeller was developed with locally available and accessible materials and the efficiency of the machine was evaluated. The obtained result shows that the efficiency of the machine is a function of the roasting temperature, the roasting duration, the moisture contents of the processed seeds and the machine feeding rate. The expeller is movable, simple in design for local fabrication, is easy to operate, requires few repairs and little maintenance and is cost effective. It is powered using a gear reduction electric motor of 5.5 Hp, the expeller has an average oil yield of 25.77% and an extraction efficiency of 70.26% and is designed to work for 8 hours per day of operation. The shaft diameter was designed to be 30 mm, while the roaster heater capacity was 2.8 kW. The designed machine is good for castor oil expression for both small- and medium-scale processing among rural and urban communities.