Eggshell as heterogeneous catalyst for synthesis of biodiesel from high free fatty acid chicken fat and its working characteristics on a CI engine

Abstract This investigation is a new attempt to utilize the low cost chicken fat and waste chicken eggshell as catalyst for the production of chicken oil biodiesel and optimizing the transesterification process parameters. The performance, combustion and emission characteristics of the diesel engine have been analyzed by using the produced biodiesel. Esterification is carried out to reduce the free fatty acid of the chicken oil below 1 mg KOH/g of oil. The transesterification process variables are optimized using response surface methodology and the experiments are conducted based on central composite design. The optimum transesterification conditions are 1:13 M ratio, catalyst concentration of 8.5 wt.% of oil, 5 h reaction time, 57.5 °C reaction temperature and fixed agitation speed of 500 rpm. The most significant factor affecting biodiesel yield is identified as molar ratio. Validation of the model shows that the maximum biodiesel yield 90.41% is close to the predicted value 92.29%. Reusability study of the recovered catalyst has been done. The engine emission study shows carbon monoxide, hydrocarbon and filter smoke number of the pure biodiesel and its blend are lower than diesel. The heat release rate for diesel is higher than all other test fuels. Finally, the experimental work reveals that chicken fat and eggshell as catalyst could be a suitable feedstock for biodiesel production.