Estudo da produção de biocombustíveis para o setor da aviação obtidos pela desoxigenação de ácidos graxos do óleo de babaçu.

Abstract

The search for routes to obtain aviation fuels from renewable feedstocks that are efficient and more profitable, using low cost catalysts and seeking less hydrogen dependency, has become extremely important due possible petroleum depletion and the increase of greenhouse gas emissions. A high quality aviation fuel may be obtained using vegetable feedstocks, but severe pressure conditions and additional hydrogen loads, in addition to the use of solvents and catalysts supported by noble metals, represent economic disadvantages. In this sense, vegetable oils cam be hydrothermally treated to produce fatty acids and then these will be deoxygenated (in the presence or not of hydrogen). In deoxygenation, the oxygen content is removed by the release of H2O, CO2 and CO (hydrodeoxygenation, descarboxylation and descarbonylation, respectively). In this study, fatty acids were obtained from the hydrolisys of babassu oil, in the presence of water in a subcritical state, without the use of catalysts. Experiments were carried out in a batch reactor under different temperatures (250 °C, 275 °C, 300 °C) and different oil to water ratios (1:38, 1:75, 1:150). Conversions higher than 80% wt were obtained in reaction times of less than 10 minutes for all temperatures and molar ratios tested. In addition, the catalytic deoxygenation process of fatty acids in aqueous medium in a subcritical state, with activated carbons catalysts was studied. For this study, the oil to water ratio of 1:140, temperature of 300 °C, reaction time of 3 and 6 hours and 800 rpm of agitation was used. The results revealed the saturation of 60% of the double bonds present in the fatty acid, obtaining a product composed mainly of saturated carbon chains that still retain the characteristic of carboxylic acid. Finally, in orden to integrate the hydrolysis of babassu oil in subcritical water with the commercial hydroprocessing of esters and fatty acids process (HEFA), simulations were carried out both of the individual hydrolysis and hydroprocessing processes, as well as the general process integrating the two previously mentioned and using the commercial software Aspen Hysys®.