Synthesis of Biodiesel from Nigerian Waste Restaurant Cooking Oil: Effect of KOH Concentration on Yield

Abstract

Indiscriminate extraction and lavish consumption of fossil fuels have led to reduction in underground carbon- based resources. This has necessitated the search for alternative fuel from renewable sources. Waste cooking oil (WCO) has been identified as a renewable resource from which biodiesel can be produced. Methanolysis of WCO to obtain WCO biodiesel was employed via potassium hydroxide (KOH) catalyst. ASTM and EU standard fuel test performed on the WCO biodiesel gave reasonable result as alternative biodiesel fuel. The effect of KOH concentration on WCO biodiesel is investigated, with a view to identifying the catalyst concentration corresponding to optimal yield. Three replicated methanolysis experimental runs were employed out for each of the KOH concentration 0.5%, 0.75%, 1.0%, 1.25%, 1.50%, 1.75%, 2.0 % and 2.5% (by mass of WCO) under identical typical methanolysis reaction condition of 60oC temperature, 60 minutes and 22% methanol (by mass of WCO). Results obtained gave 91.1%, 95.9%, 97.1%, 86.7%, 75.20%, 73.3%, 72.1%, 72.4% average WCO biodiesel yield for the respective feedstock ratio. THE KOH concentration 1.0% resulting in maximum WCO biodiesel yield (97.1%) is therefore recommend as optimum, within the constraint of the typical methanolysis process employed. Few standard fuel test results of the WCO biodiesel are within biodiesel specification. This finding will go a long way in improving energy security in Nigeria and the world in general.