MediÃÃo experimental e prediÃÃo da volatilidade de flex fuels

AUTOR(ES)

Lysandreya Penha Costa

DATA DE PUBLICAÇÃO

2005

RESUMO

Oxygenated additives are added to gasoline to increase its antiknock properties. These compounds are substitutes for additives that are environmentally more aggressive, like tetraethyl lead. The oxygenated used in the Brazilian gasoline is the anhydrous ethanol 20% the 25%, which can affect the fuel properties strongly. In the last decade, the number of vehicles equipped with motors designed to operate with a fuel composed of gasoline and hydrated ethanol at any ratio, known as flex fuel, has increased. In this work, vapor pressure data of commercial gasolines mixed with anhydrous and hydrated ethanol were measured to evaluate its volatility, an important property for a good motor performance. The ASTM methods D 5191 and D 6378 were used to measure vapor pressure. Results showed that the presence of ethanol and water strongly affect volatility of the mixture compared to the original gasoline. With a vaporliquid equilibrium approach, considering the flex fuel a pseudo ternary mixture (gasoline/ethanol/water), the vapor pressure data were correlated by the NRTL activity coefficients model. The overall mean deviation obtained, 0.30 kPa, was smaller than the standard deviation of 1.5 kPa expected for the measurements

ASSUNTO(S)

engenharia quimica alcohol flex fuel Ãlcool flex fuel pressÃo de vapor gasolina gasoline vapor pressure

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