Base catalysed transesterification of used cooking oil to biodiesel.

Abstract

Biodiesel from Used Cooking Oil (UCO) is an effective alternative fuel for conventional diesel and can be directly used as fuel in a diesel engine without any modifications to the engine. It has many positives like high biodegradability, reduction in greenhouse gas emissions, non-sulfur emissions, non-particulate matter pollutants, low toxicity, and excellent lubricity and is obtained from renewable source like vegetable oils, animal fat and many others. The major objective of this work was production of Biodiesel by transesterification process of Used cooking oil and the other objectives were, the physicochemical characterization of the UCO, as well as the effects of process variables on biodiesel yield, were evaluated. Also, optimum levels of process conditions for optimum production of biodiesel were determined. The UCO with methanol and catalyst were heated in a hot plate-magnetic stirrer at a temperature of 60°C and operated at 200 rpm. Potassium hydroxide (KOH) was used as catalyst. A gas chromatography− mass spectrometry (GC-MS) analysis was done on the biodiesel to be able to identify potential impurities and compounds present. The physicochemical characteristics (acid value, free fatty acid, density, kinematic viscosity) of UCO were also obtained. From the results, the possible optimum conditions of the process variables for transesterification process using KOH catalyst were found to be as follows: reaction time of 50 min, methanol to oil molar ratio of 9:1 and the catalyst loading of 0.25g. At these optimum conditions, the optimum yield of biodiesel obtained from transesterification of UCO was found to be 94.7%. Thus, in comparison, the transesterification of 9:1 resulted in high biodiesel yield. Conclusively, UCO has good potential to be used for bio-diesel production.