Production of Biodiesel from Used Cooking Oils

This paper studied Biodiesel production from waste/used cooking oil by transesterification reaction. Methanol was used as a reactant and KOH was used as a base catalyst. Production was carried out in a lab scale batch reactor. The feedstock was collected from street sellers (SS), residential homes (RH), hotels (H) and a cheese ball factory (CBF). Important fuel parameters such as viscosity, density, flash point, Cetane number, carbon residue and acid value were determined and compared to ASTM standards for biodiesel. All parameters investigated falls within ASTM standards. Oil sample from the cheese ball factory produced the highest percentage yield of biodiesel compared to the other samples. The effect of methano to oil molar ratio was explored, keeping other process parameters constant. Analyses of the four oils (SS, RH, H, and CBF) revealed that, a surge in methanol/oil ratio results to a higher yield till a peak yield is attained. From this study it was observed that optimum methanol:oil molar ratio for biodiesel production from all the samples of waste cooking oil falls around 8:1. Effect of base catalyst concentration (KOH) on yield was also investigated. For each oil sample, the biodiesel yield improved with increase in catalyst concentration. The highest yield was obtained with 1% catalyst concentration. Exhaust particulate matter (PM) emissions of Biodiesel and fossil diesel were compared. PM emission from fossil diesel far outweighs biodiesel.