Local rice processing by small scale agro-processor has suffered tremendous setback ranging from stone presence and foreign materials in processed rice. It has become critical to develop a domestic rice de-stoning machine that can be utilized by small scale agro-processors. As a result of these bottlenecks this paper has focused on developing a destoning machine that utilizes water medium for stone separation. The design was built using locally accessible materials. Major components of the machine being reservoir, hopper, de-stoning chamber, washing chamber, impeller, water filter, and brush drum. The developed de-stoning machine was powered by a 1.8 kW variable electric motor that communicated the rotating motion of the driving pulley to the driven pulley, which was supported by bearings, through a V-belt. The machine was developed and evaluated for its efficiencies with respect to stone separation and rice cleaning using 2 kg clean rice with 20 incorporated small stones of different sizes. It was discovered that 2 kg/10minutes and 20.04 kg/hour of processed rice were de-stoned at a speed of 400 rpm, which is the optimal speed for maximum separation process. The de-stoning machine's effectiveness in terms of stone removal is approximately approaching 100 percent free of impurities. This discovery elucidates the potential to deal with the challenges of stone removal from locally produced rice using hand and manual method, which are inefficient, time and energy consuming, therefore this developed machine acts as a rice processing industry innovation.

Hydrocyclone is an equipment that uses a cyclone or tangential injection flow process with centrifugal forces to separate liquids of different densities. The denser liquid move downwards in a spiral path into an underflow chamber, while clean liquid which is less dense move upwards to the center of the spiral, towards the top outlet. Colman and Thew’s hydrocyclone geometry analysis approached was used in the design and the assumed inlet chamber diameter (D) used for this design was 150 mm and a reducing section length of 1500 mm at a reducing angle of 20°. The capacity of the designed hydrocyclone system in volume is 5.5 liters. The developed machine was tested with 15 liters of palm kernel oil (PKO) as raw material using two different pressures gauge (70 and 80 kPa) and also effect acid concentration (sulphuric acid) at 3 different experimental runs. After the experiments, it was deduced that at constant temperature level, as the pressure rate increases, there is a corresponding increase in the discharge rate at the underflow and overflow outlets where 2.04 minutes and 1.67 minutes were used to separate biodiesel and glycerin under 70 and 80 kPa respectively. Also, it was deduced experimentally that PKO with sulphuric acid gives a higher yield of biodiesel of 47.74% while the one without has 38.49% yield under same experimental and operational conditions.