The Nile tilapia viscera oil extraction for biodiesel production in Brazil: An economic analysis

The present study evaluates the viscera of the Nile tilapia (bred in captivity) for bio-oil production and its impact on the biodiesel supply chain. We report in detail all the steps, from viscera extraction to the economic viability of the produced biodiesel, that led to the development of an oil extraction unit and the separation of the resulting sludge. Given that the Nile tilapia's viscera have a mass balance of 10% and that about 40-50% of the oil can be obtained from the viscera, the proposed oil extraction unit is capable of producing of 201.08 kg of oil in an 8-h operational time shift. Physicochemical tests conducted under the American Oil Chemists' Society's methodology indicate that the oil obtained has an acidity level of 0.15 mg KOH/g. The acidity level of the final biodiesel obtained is within the parameters set by the related production directives; that is, 0.22 mg KOH/g. A detailed economic analysis of the developed system showed a net present value (NPV) of US$ 93,561.13 and an internal rate of return of 45%. As for construction investment, the payback period is 1.9 years. In sensitivity aspects, the variance in viscera obtained in 90% over the reference value (US$ 0.05) in the raw material source will lead to a value of US$ 10,443.15 in NPV. The processing capacity will reach its break-even point a 60% of the installed production capacity when there will be neither loss nor profit. Therefore, it is possible to conclude that this new biomass source will be viable along with the development of new technology to process it, generating value for fish viscera and diminishing the environmental impacts of fish farming.