DESIGN AND PRODUCTION OF A VERTICAL PALM FRUIT DIGESTER

This work ‘Design and Production of a Vertical Palm Fruit Digester’ has been carefully carried out. The digester was initially conceived to meet design requirements like functionality, strength and robustness, corrosion resistance, capacity delivery, aesthetics, efficiency and others. To achieve the design requirements design software (AutoCAD) and laptop was used for the engineering drawing of detailed parts and assembly drawing, while design calculations and analysis of loads and forces acting on the vertical palm fruit digester was carried out to assist in the materials selection for the production of the digester. The detailed parts were produced according to the design and standard parts selected in line with design calculations. The digester was assembled using welding machine, bolts and nuts and the right fastening strength and technique was used to ensure rigidity and prevent leakages. The digester was then evaluated for performance and the results revealed that a vertical palm fruit digester was designed, produced and tested. The designed digestion machine was evaluated in regards to two major parameters, namely, the amount of oil produced (throughput and yield) and the quality of the oil produced (with the measures of moisture content, free fatty acid levels, viscosity, and retention of micronutrients). The findings confirm that operating conditions, including sterilisation time, storage time, shaft speed, and blade design, have a strong effect on machine performance. The machine digesting capacity remained high under different machine-set-ups with the highest conditions producing above 340 kg/h, and at 94% efficiency. Optimal sterilisation (120 minutes) and storage (3 days) resulted in oil that contained low amounts of water and low free fatty acids with 3 days maintaining its 0 -tocopherol and 0 -carotene. Long sterilisation or long storage however resulted in an increase in FFA, decrease in antioxidants, and colour decay, which are indicators of oxidative degradation. The total cost of producing the machine is ₦600,000 ($400) and the most expensive part of the machine is the gasoline motor which was ₦100, 000 ($66.67) whose value is approximately 16.7 percent of the total cost. The locally-developed machine is also much cheaper than imported palm fruit digestion machines, which can range between ₦2,000,000 ($1333.33) and ₦3,500,000 ($2333.33) depending on capacity and specifications. This affordability will make it available to rural cooperatives, small-scale processors, and community-based businesses, which is why it will support the local content policy in Nigeria and lessen reliance on imported equipment.