PRODUCTION OF BIODIESEL FROM ANIMAL FATS AND EVALUATING ITS POTENTIAL AS AN ALTERNATIVE FUEL

Abstract

With the increasing trend towards the use of renewable energy resources, the use of biodiesels is highly emphasized. This paper reports findings of a survey which involved data gathering from 13 meat processing plants and slaughter houses near Nairobi City to establish the potential for animal fat production in Kenya. The paper also reports results of activities aimed at demonstrating the production and utilization of biodiesel from animal fats. In this aspect, a 100-litre animal fat biodiesel processing unit was fabricated and used for producing biodiesel from animal fat. The suitability of the produced biodiesels as alternative fuels was evaluated by carrying out engine performance tests. The results indicated that beef cattle and camels can produce 5.67kg of animal fat, while pigs, sheep and goats can produce 7.8 kg, 2 kg and 1 kg, respectively. This would provide an approximated total of 180,498 tonnes of animal fat production potential in Kenya as at 2009. From the actual animal slaughter figures, a total of 21,265 tonnes of animal fat can be produced annually in the country. With an 70% biodiesel yield from the 100-litre processor, a total of 14,886 tonnes of biodiesel can be produced. The biodiesel produced from lard and tallow feedstocks adhered to the required density and viscosity limits of 0.87894g/ml; 0.87884g/ml and 5.7379mm2/s and 5.7479mm2/s respectively. Observations for flash point and ash content were 59oC; 60oC; and 0.007% and 0.009% respectively. Water content of 0.001% and pour point of less than 0oC for both lard and tallow biodiesels were observed. Contents of sediments were undetectable for both lard and tallow biodiesels. Engine test results showed that at 100% load, the specific rate of fuel consumption (sfc) for B100 Lard and B100 tallow were 119.79% and 124.43%, respectively as compared to fossil diesel while at 25% load, the rates reduced to 1.64% and 1.22% respectively. For the B10 blends, the specific rate of fuel consumption figures were lower than fossil diesel at 4.82% and 7.29% for B10 Lard and B10 Tallow respectively at 100% load. At 25% engine load, the consumption for B10 lard was 0.60% above fossil diesel while that of B10 tallow was 6.81% lower than fossil diesel.