Non-Catalytic In-Situ transesterification of Citrus Peel Waste into Biodiesel via Supercritical Technology: Optimisation by Response Surface Methodology

Abstract

Biodiesel production via supercritical technology has been reported as a novel technology for transesterification of different vegetable oils. However, foods waste materials containing oil and other lingo-cellulosic materials such as waste orange peels have not been widely reported. In this experimental research, direct in-situ supercritical transesterification of waste orange peels into biodiesel was conducted. The reaction conditions for optimal biodiesel yield were determined using response surface Methodology (RSM). Finding from the results revealed that the optimal conversion obtained was 58.95%against 60.77%predicted obtained under the following reaction conditions-reactant molar ratio of 5/70, reaction time was 15 minutes while reaction temperature was 260°C. Temperature was the most significant factor. Predominant fatty acids identified include oleic and stearic acids with highly unsaturated acids identified as well. Fuels properties were within the standard limits except in few cases. It was concluded that supercritical transesterification of fresh Citrus Peel Waste CPW was viable for the production of biodiesel under the conditions stated.