Production and evaluation of biodiesel from rambutan (Nephelium lappaceum L.) seed oil

Abstract

The study aimed to search for alternative fuels that could potentially solve the gradual depletion of worldwide petroleum reserves and the increasing exhaust emissions leading to environmental hazards. Food waste can be a potential alternative energy source that can be a substitute for petroleum-based diesel fuels, and the main focus of this study was to use rambutan seeds as the source. Various tests were performed to determine if rambutan seed oil converted into rambutan methyl ester (RME) or B100 and B2 by transesterification is an efficient source of energy and identifies the percent yield of the extracted oil. The rambutan seed oil was also compared to coco methyl ester (CME) 100 and CME2 to determine if the extracted oil meets the specification set by the Philippine National Standard (PNS) of the Biofuel Act of 2006. The extracted crude seed oil has undergone base-catalyzed transesterification using sodium hydroxide (NaOH) as the catalyst to produce biodiesel using % by weight proportion of NaOH to oil. It was then tested to confirm the product’s conformity to the PNS for biodiesel and its blend, B2. The highest oil yield gathered was a result of variation in soaking time. Emission testing for car engines was assessed for its application, with comparable results to the commercially available diesel. The results of the experiments revealed that the soaking extraction method for rambutan seed oil could produce a higher yield at its optimum contact time. Qualitative tests of physicochemical properties showed that rambutan methyl ester is comparable to commercial coco methyl ester. The five-day contact time and weight % proportion of NaOH to oil for transesterification produced the highest % of methyl ester. The results suggest the potentiality of rambutan seed oils as local feedstock for biodiesel production and as an innovative additive to present diesel available.