Biodiesel From Moroccan Waste Frying Oil: The Optimization of Transesterification Parameters Impact of Biodiesel on the Petrodiesel Lubricity and Combustion

The transesterification reaction of Moroccan waste frying oil (WFO) by methanol, using sodium hydroxide and potassium hydroxide as homogeneous catalysts, was studied. The waste oil was recovered from Moroccan popular restaurants after repeated deep-frying of spiced fishes. The effects of methanol/oil molar ratio (5: 1-12: 1), catalyst concentration (0.5-2 wt%), reaction temperature (30-65 degrees C), and type of catalyst were investigated. The extent of the transesterification reaction was followed by gas chromatography (GC) and H-1-NMR spectroscopy, determining the concentration of methyl esters at different reaction times and triglyceride conversion respectively. The optimal reaction conditions for the transesterification of WFO were found at the reaction temperature of 65 degrees C, reaction time of 60 min, molar ratio of methanol to oil equal to 7: 1, and in presence of NaOH as catalyst. The corresponding maximum ester yields were 93.5 wt% for the studied WFO. The lubricity test showed that 1 vol% of biodiesel in petrodiesel leads to the value fixed by the European regulation, namely 460 mu m. The optimized conditions were used to produce biodiesel at small scale. The resulting product was tested in a diesel electricity generator engine, which operated in real conditions. The results showed that biodiesel combustion leads to a higher concentration of CO and a decrease in NOx emission as compared with a petrodiesel-fuelled engine. An optimization of the operating parameters of the engine would guarantee lower CO emissions in conformity with literature and regulations.