Air quality standards set forth by the Clean Air Act and its amendments have established guidelines for reductionof harmful ground level emissions from the aviation sector. Biodiesel, defined as the monoalkyl esters of fatty acids derivedfrom vegetable oil or animal fat, in application as an extender for combustion in compression ignition (diesel) engines, hasdemonstrated a number of promising characteristics including reduction of exhaust emissions. This work examines the fuelproperties of BioJet fuel blends consisting of 0.100.30 vol. frac. methyl soyate (SME) in JP8 and in JP8+100 jet fuels.Testing of cold flow properties indicated that blends with as little as 0.10 vol. frac. SME may limit operation of aircraft tolower altitudes where ambient temperature remains warmer than 29C. Treatment of SME with cold flow improver additivesmay decrease this limit to 37C. Blends with winterized SME gave the best results, reducing the limit to as low as 47C,a value that meets the standard fuel specification for JP8. Water reactivity studies indicated that SME/JP8 blends absorbedvery little water from buffered solution following contact with the oil phase. Although interface ratings for blends with upto 0.50 vol. frac. SME were 1b (clear bubbles covering not more than 50% of the interface) or better, separation ratingsno better than (3) (formation of cloudy suspensions in the oil layer) were observed. Even though fatty derivatives such asbiodiesel undergo oxidative degradation more readily than jet fuels, careful production, transport, and storage of BioJet fuelsshould not present a significant problem.
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Robert O. Dunn (2001) studied this question.