Energy self-sufficiency of smallholder oil palm processing in Nigeria

The study evaluated the contribution of various energy sources to the smallholder processing of oil palm in Nigeria. Ten small-scale palm oil processing mills were visited at Elele, River State, Nigeria for sample collection. The weight of the various solid wastes generated and utilized for boiling process were measured including EFB (empty fruit bunch), PPF (palm press fiber), PKS (palm kernel shell) and chaff, while the volume of diesel used for digestion was also measured. The processing of 1 tonne of FFB (fresh fruit bunch) in the mill yields 63.4–77.1 L of CPO while the following waste by-products were generated from the FFB; 24 to 31% EFB, 23 to 28% PPF, 10 to 12% PKS and 1.4 to 2.4% chaff. Out of the total biomass generated by the mills only 12.74–22.25% EFB, 24.43–33.38% PPF, 2.71–6.71% PKS and 15.12–49.04% chaff were utilized by the various mills for fruit boiling/sterilization, indicating that the majority of biomass wastes is unutilized in the mills. The volume of diesel utilized by the mills for digestion is quite low ranging from 0.6 to 0.8 L. The gross calorific values of the waste biomass are EFB 16.970–18.537 MJ/kg, PPF 16.472–21.037 MJ/kg and PKS 19.378–21.614 MJ/kg. The total energy utilized by the mills for processing 1 tonne of FFB ranged from 2179.43 to 3014.31 MJ. Out of these, biomass energy accounted for 98.22–98.75%, while fossil fuel accounted for the remaining 1.25–1.78%. The study concluded by suggesting innovative ways of substituting the <2% fossil fuel contribution with the direct use of pre-heated palm oil to fuel the digesters.