Síntese de bio-hidrocarbonetos via catálise heterogênea para a produção de bioquerosene de aviação e diesel verde

Abstract

In recent years, one of the most challenges in the biofuel field is the production of dropin biofuels production, such as green diesel and bio-jet fuel, which are oxygen-free biofuels composed by liquid hydrocarbons. For producing bio-hydrocarbons were used, in this thesis, soy oil, cashew nut liquid shell, and diphenyl ether as a model compoundof lignin. To produce bio-hydrocarbons from soybean oil deoxygenation was performed a screening with different catalysts: zeolites HBeta and ZSM-5, FCC catalyst, which is used in the process Fluid Catalytic Cracking, palladium on activated charcoal (Pd/C) and niobium phosphate catalyst (NbOPO4). Between these, NbOPO4 catalyst showed a greatperformance in the production of drop-in biofuels. The performance of niobium phosphate was evaluated under different reaction time (3 e 5 h), catalyst amount (0 to 25%) and temperature (300 e 350 °C), using 10 bar H2 or 10 bar N2. The redox and acid properties of NbOPO4 led to the simultaneous formation of linear and branched alkanes, cycloalkanes, olefins and aromatics compounds. The optimization process led to highyields (76-97%) of hydrocarbons, mainly, in the range of bio-jet fuel (60%), followed by green diesel (40%) and biogasoline (20%). Cashew nut shell liquid (CNSL) was used as feedstock to produce a new green diesel. The influence of the reaction parameters, such as temperature (180, 250 and 300 °C), time (5 and 10 h) and pressure (10, 20, 30 and40 bar), were investigated in the upgrading reactions (deoxygenation, hydrogenation and cracking) of CNS using palladium over activated charcoal as the catalyst, Pd/C. A 98% yield of hydrocarbons corresponding to the diesel range (C15 to C21) was obtained,using mild conditions of reaction (40 bar H2, 300 °C,10 h, 500 rpm and 10% w/w of Pd/C). Production of dicycloalkanes from the catalytic conversion of diphenyl ether (DPE), a dimeric model compound of lignin, has been investigated using a hydrophobized bifunctional Pd/HY catalyst. Partial hydrogenation of DPE was found to be essential to favor the ether bond cleavage. Among the main products from the C-O cleavage isemphasized the presence of phenol and cyclohexanone, which subsequently undergo to C-C coupling reactions (alkylation and aldol condensation). The balance between hydrogenation activity of the metal and the acidic function of zeolite played an important role for maximizing the yield of dicycloalkanes, which are desirable in the upgrading oflignin-derived compounds to bio-jet fuel formulations with excellent cold properties.