Among these materials has been tallow, traditionally used in the making of candles. Tallow is obtained from the fat in cattle, sheep and goats. Its chemical composition is based on glycerolesters of various fatty acids. The fatty acids, for the most part, resemble long chain hydrocarbons. An early suggestion for the use of tallow relied on the idea that the long hydrocarbon chain portion of the fatty acid portion of tallow could be catalytically cracked to produce the shorter chain fuel oils. An alternative strategy would be to extend current fuel stocks by addition of fuel supplements.
The aim of the project has been the exploration of the use of tallow as a fuel supplement.
Samples of various grades of tallow were obtained from the Agricultural and Food Authority, Moorepark Research Centre, Fermoy, Eire. The tallow obtained was graded 1, 2 and 6 (Table 1.1).
Of the three grades, grade 1 tallow was chosen as the starting material as it appears the most homogenous and the lightest in colour.
Our first objective was to determine whether tallow and diesel were miscible/soluble. Tallow at room temperature is a solid material with a low melting point. The tallow was added to diesel in the liquid form to ease the mixing and speed up the process at which a tallow-diesel solution was obtained. Preliminary results indicate that tallow, even in small amounts, does not remain as a stable solution in diesel.
Consequently, research has been undertaken which involves the mixing of tallow with diesel to produce a stable solution by the addition of a blending additive. Initial results have proved encouraging and further work in this direction has been undertaken. Work is also proceeding in improving the quality of the tallow given that there exists a variable quality in the tallow depending on the choice of fatty material used in preparing the tallow.