Volatility and phase stability of petrol blends with ethanol

Blending ethanol in to petrol can be associated with problems related to volatility and phase stability of the blends. Ethanol up to 20 vol% in petrol forms an azeotropic mixture with hydrocarbons. Ethanol has affinity to water and air humidity and it increases the water solubility in ethanol-petrol blends. In this work, the influence of ethanol up to 10 vol%, ETBE up to 10 vol% and hydrocarbon composition over volatility, distillation characteristics and miscibility of ethanol-petrol blends with water was studied. It was found that higher content of saturated hydrocarbons in petrol increased the vapour pressure of azeotropic ethanol blend. Aromatics and alkenes influenced the azeotrope vapour pressure, phase separation temperature and ethanol extraction in a positive way. The results showed that the ETBE can soften effects of the ethanol blending to petrol. ETBE decreased the vapour pressure and the phase separation temperature of the ethanol-petrol blends.