Estudo do coprocessamento de óleos vegetais para a conversão de bio- hidrocarbonetos na faixa do querosene de aviação

Abstract

Sustainable aviation fuel and green diesel are the main representatives of the drop-in fuels, which, in addition to being renewable, have similar composition and properties of fuels derived from petroleum, which allows their total or partial replacement. One of the most used routes to produce drop-in fuels is the hydroprocessing of esters and fatty acids (HEFA) and in this work this route was used to produce bio-hydrocarbons from the co-processing of vegetable oils such as macauba pulp oil, macauba almond oil, soybean oil and used cooking oil. Macauba is a native Brazilian palm tree that has high oil productivity and soybean is the most produced oilseed in Brazil. The feedstocks were characterized by infrared spectroscopy and gas chromatography. In addition, tests were carried out to determine acidity, iodine and saponification indexes, relative density, fatty profile, heat of combustion, water content and kinematic viscosity at 40 °C. The catalysts were prepared and characterized by X-ray diffraction and inductively coupled plasma optical emission spectroscopy. The bio-hydrocarbons synthesis was catalyzed by palladium supported on magnesium oxide (Pd/MgO), with the following conditions: 20 bars of hydrogen at 350°C for 4 hours in stirring speed of 150 rpm. The products with the best performance were obtained from the co-processing of macauba pulp oil with soybean oil with 86 % yield for bio-hydrocarbons. The yield for bio-hydrocarbons with the carbon length of the jet fuel range (C9 -C16) was 56 %, which composed mainly of linear paraffins, with heat of combustion of 44.96 MJ/kg, a suitable value for its use as fuel. For comparison, additional reactions were carried out, varying the metals impregnated in the catalyst support, for this purpose cobalt (Co), nickel (Ni) and ruthenium (Ru) were tested. Furthermore, the reaction atmosphere was varied, replacing H2 with N2. The products from the additional tests also showed good yields (51-71 %) on bio-hydrocarbons, especially on bio-hydrocarbons in the jet fuel range. The results obtained in this work, in addition to being unprecedented and promising, also contribute for a more sustainable world, since they have the potential to be used on an industrial scale to produce jet fuel, besides green diesel and biogasoline.