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A study of petrol and diesel fuel blends with special reference to their thermodynamic propeties and phase equilibria

The ternary phase behaviour of the n-heptane-l-propanol-water system was studied and compared with the theoretical prediction based on the UNIQUAC model for non-electrolyte solutions. The results showed that this model adequately approximated experimental studies. The excess enthalpies and excess volumes for several binary mixtures were determined. The excess enthalpies were measured using a LKB flow microcalorimeter and the excess -volumes determined using a PAAR densitometer. The study showed that no significant enthalpy or volume changes occurred when petrol/n-heptane were mixed with alcohols . Ternary phase diagrams, including tie lines have been determined for a number of petrol-alcohol-water systems (including the Sasol blend of alcohols). The tie line results show that the concentration of water in the water-rich layer is strongly dependent on the type of alcohol used. The Sasol alcohol blended with petrol resulted in a high water concentration in the water-rich layer which forms on phase separation. This is believed to contribute significantly to the corrosion problems experienced by motorists using the Sasol blended fuel on the Witwatersrand. The effect of temperature on several of these blends was included in the study. Diesel-alcohol blends and the co-solvent properties of ethyl acetate investigated. Ethyl acetate ensures miscibility at low concentrations for diesel-ethanol blends. Octyl nitrate and two cetane improvers from AECI were assessed in terms of their ability to restore cetane rating of blended diesel fuel to that of pure diesel fuel. The results indicated that all three samples were successful in this application. / KMBT_363

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:rhodes/vital:4065
Date January 1986
CreatorsHayward, Caroline
PublisherRhodes University, Faculty of Science, Biochemistry, Microbiology and Biotechnology
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis, Masters, MSc
Format172 leaves, pdf
RightsHayward, Caroline

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