The use of waste cooking oil as an alternative fuel for the diesel engine

[Abstract]: This research project is directed toward those who are looking for an alternative source of fuel for the diesel engine. This report is an investigation on how a sole user can design and fabricate a machine to manufacture biodiesel, how well the biodiesel compares with diesel in regards to performance and also the economical benefits which can be achieved by using biodiesel blended fuels. This report firstly analyses what biodiesel is, and how it can be made from waste cooking oil through both a chemical and physical process. Based on these processes, a conceptual design analysis of a biodiesel plant was then conducted and a final design proposal was developed. The proposal was then commissioned for construction and completed several months later. The biodiesel that was produced by the newly manufactured biodiesel plant was then tested at the University of Southern Queensland’s engine testing laboratory. Several blends of biodiesel with diesel were tested ranging from pure diesel, to 100% biodiesel in a small IC engine. It was found that the biodiesel blends compared quite well to the overall performance of diesel, where B25 (25% biodiesel, 75% diesel) was found to replicate the general performance of diesel the closest, B50 (50% biodiesel, 50% diesel) produced the lowest brake specific fuel consumption, B75 (75% biodiesel, 25% diesel) produced the highest usable power and torque and B100 (100% biodiesel) was found to have the highest thermal efficiency. An economical analysis was then conducted for each blend of fuel where the aim was to determine which blend of fuel was the most economical alternative to diesel. Assuming that the general maintenance (oil change etc) of using biodiesel remained the same as that of diesel, it was found that using B100 will provide the highest economical gains when used and the initial cost of the biodiesel plant will be recovered the quickest. Based on these investigations it was concluded that biodiesel is indeed a feasible alternative to diesel that can save the user in excess of 28% on their fuel costs, and that will yield similar performance characteristics when used in a common IC engine.