Thermal analysis of the residue obtained from gasoline distillation mixed with hydrated ethanol for flex-fuel technology

摘要

The generation of carbon monoxide during the combustion of gasoline is a serious environmental problem in big cities. The addition of ethanol in gasoline decreases the concentration of CO emissions. Thus the application of a mixture of gasoline-alcohol is a very interesting technology, and some countries such as United States, China, Australia and Japan are interested in this flex-fuel technology. The residue of the distillation corresponds to the part of the gasoline that surplus after the end point of boiling. The occurrence of high percentage of residues can be related in such a way with the ratio of composites weighed, how much with the thermal instability of the final, remaining fractions after the continuous distillation of the fuel. In this work, thermal study of the final residue of the distillation from gasoline mixed with hydrated ethanol samples was carried out by thermogravimetry. The gasoline was mixed with 20, 40, 60 and 80 %volume of ethanol, and the samples were called as: G80:A20, G60:A40, G40:A60 and G20:A80, respectively. The distillation of the samples was carried out according the ASTM D86 using an automatic distiller ISL AD86 model equipment. In the analysis procedure, 100 mL of each sample was used. At the end of the distillation process, ca. 1 mL of the residue of the samples were obtained and analyzed by thermogravimetry in the range of temperature from 30 to 600 °C, at heating rates of 5, 10 and 20 °C min~(-1), under dynamic synthetic air atmosphere, flowing at 30 mL min~(-1). The experiments were carried out in a thermo balance from Mettler Toledo, TGA/SDTA-851 model. The specific mass of the samples was determined according the ASTM D4052, using a digital densimeter Mettler Toledo DE-40 model.