Combustion, emission and engine performance characteristics of used cooking oil biodiesel—A review

• Published in: Renewable & sustainable energy reviews Vol. 14; no. 9; pp. 2863 - 2873
• Main Authors: Enweremadu, C.C., Rutto, H.L.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2010; Elsevier
• Series: Renewable and Sustainable Energy Reviews
• Subjects: Air pollution caused by fuel industries; Alternative fuels. Production and utilization; Applied sciences; Biodiesel; Blends; Combustion; Cooking; Diesel engines; Emissions; Energy; Energy. Thermal use of fuels; Engine performance; Engines; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuels; Heating; Metering. Control; Miscellaneous; Used cooking oil; Used cooking oil Biodiesel Diesel engines Emissions Combustion Engine performance; Combustion; Diesel engines; Used cooking oil; Biodiesel; Engine performance; Emissions
• ISSN: 1364-0321; 1879-0690
• DOI: 10.1016/j.rser.2010.07.036

As the environment degrades at an alarming rate, there have been steady calls by most governments following international energy policies for the use of biofuels. One of the biofuels whose use is rapidly expanding is biodiesel. One of the economical sources for biodiesel production which doubles in the reduction of liquid waste and the subsequent burden of sewage treatment is used cooking oil (UCO). However, the products formed during frying, such as free fatty acid and some polymerized triglycerides, can affect the transesterification reaction and the biodiesel properties. This paper attempts to collect and analyze published works mainly in scientific journals about the engine performance, combustion and emissions characteristics of UCO biodiesel on diesel engine. Overall, the engine performance of the UCO biodiesel and its blends was only marginally poorer compared to diesel. From the standpoint of emissions, NO x emissions were slightly higher while un-burnt hydrocarbon (UBHC) emissions were lower for UCO biodiesel when compares to diesel fuel. There were no noticeable differences between UCO biodiesel and fresh oil biodiesel as their engine performances, combustion and emissions characteristics bear a close resemblance. This is probably more closely related to the oxygenated nature of biodiesel which is almost constant for every biodiesel (biodiesel has some level of oxygen bound to its chemical structure) and also to its higher viscosity and lower calorific value, which have a major bearing on spray formation and initial combustion.