Preliminary investigation of transesterified waste cooking oil (WCO) as a biodiesel

Abstract

This research focuses on the production of cheap biodiesel from waste cooking oil [WCO], using the transesterification method. A disadvantage of biodiesel produced from virgin oils is that it is still more expensive than D2 petroleum diesel [diesel sold in filling stations]. The trust therefore of this study is the production of relatively cheap biodiesel, from a cheap feedstock. The conversion of the WCO involved the use of excess methanol and potassium hydroxide (as a homogenous catalyst), in a separatory funnel with vigorous agitation for 30 mins at a temperature of (40 0C). The mixture was thereafter allowed to stand overnight, and two layers were observed. The upper biodiesel [waste cooking oil methyl ester-WCOMe] layer was purified by washing with water [10ml x 5] and dried (anhydrous sodium sulphate). Improvised procedures were used to determine the following fuel quality parameters (viscosity, flash point, cloud point and pour point) and afforded 29.8 sec, 240 0C, 1.0 0C and 0.8 0C respectively. The reaction was conducted within 30 mins at 40 0C. Palm kernel oil methyl ester [PKOMe] was produced from palm kernel oil [PKO] using the same process for WCOMe and the cost of production based on feedstock price only compared. Use of WCO feedstock drastically reduced the production cost of WCOMe when compared to palm kernel oil methyl ester [PKOMe]. Production cost of WCOMe was free compared to N520.83 L-1 for PKOMe. The presence of fatty acid methyl esters in WCOMe and PKOMe was confirmed by GC. Waste cooking oil as feedstock for biodiesel should therefore be encouraged as it affords a relatively cheap fuel and remediates the disposal of WCO as an environmental hazard.