LOW-TEMPERATURE PROPERTY AND ENGINE PERFORMANCE EVALUATION OF ETHYL AND ISOPROPYL ESTERS OF TALLOW AND GREASE

Three monoalkyl fatty acid esters derived from tallow and grease were prepared by lipase-catalyzed transesterification and evaluated as pros pective diesel engine fuels. The low-temperature properties of the est ers, both neat and as 20% blends in No. 2 diesel fuel, were evaluated. Those properties included cloud point, pour point, cold filter pluggi ng point, low-temperature flow test, and crystallization onset tempera ture. Other properties of the esters, such as kinematic viscosity, hea ting value, and calculated cetane number, also were determined. All th ree esters had acceptable physical and low-temperature properties, as well as acceptable fuel properties at the 20% level in diesel blends. Engine performance and emissions for the ester blends were determined in a direct-injection, matched two-cylinder diesel engine. Among the m onoalkyl esters studied, ethyl greasate had better properties and engi ne performance characteristics than the two tallow esters. For the lat ter eaters, isopropyl tallowate had better properties than ethyl tallo wate.