Energy requirements for palm‐kernel oil processing operations

Abstract

Direct energy utilization in nine palm‐kernel oil (PKO) mills located in Southwestern Nigeria was analyzed. The mills were stratified into small, medium and large‐scale categories, based on their modes of operations and production capacities. Evaluation of energy usage was carried out in the seven readily defined unit operations namely: palm‐nut drying, palm‐nut cracking, palm‐kernel roasting, palm‐kernel crushing, PKO expression, PKO sifting and PKO bottling/pumping. PKO extraction rates in the three mill categories were evaluated. The average PKO extraction rate for small, medium and large mills were 48.45 percent, 42.68 percent and 36.24 percent, respectively. The total energy expenditure in small, medium and large‐scale PKO mills were 350.89MJ/tonne, 230.70MJ/tonne and 181.74MJ/tonne, respectively. This suggests that the unit energy requirement for PKO output decreases as mill capacity increases. The four most highly energy‐intensive operations identified were palm‐nut cracking, palm‐kernel roasting, palm‐kernel crushing and PKO expression, altogether accounting for 95.29, 92.14 and 93.65 percent of total energy used in small, medium and large‐scale mills, respectively.