Production of Renewable Diesel by Hydrotreating of Palm Oil with Noble Metallic Catalysts

Abstract

Biofuels have to be produced from biomass under sustainable conditions accomplishing appropriate characteristics and specification for their use as transportation fuels. Nowadays, renewable diesel appears as a more promising option than traditional biodiesel (methyl ester), because its properties are closer to diesel, facilitating its use in current diesel motors. Hydrotreating process for obtaining renewable diesel requires catalysts which are generally supported metals. In these catalysts, the active phase can be a reduced metal, sulphide, carbide or phosphide metallic or bimetallic; while the support can be active carbon, alumina or zeolite. The reduced metals are the simplest to prepare. They do not undergo leaching and have good selectivity. In this work, the behaviour of these catalysts in the production of renewable diesel from palm oil was evaluated. Tests in a STA (simultaneous TGA and DSC) were used to compare the catalytic activity of Pt, Pd, Rh and Ru catalysts, studying the effect on selectivity and conversion of the type and concentration of the active phase, as well as the support. The tests were carried out at 5 MPa of H2 from 20 °C to 290 °C with a temperature ramp of 10 °C/min. IR and GC-MS were also used for identifying the products obtained at the best operating conditions. The best results were obtained for Rh/C, Ru/C and Pt/USY (CBV-780), mainly generation of hydrocarbons such as n-C15 alkanes up to n-C18. Also, the appearance of fatty acids with the same number of carbons was detected.