Renewable fuels production from the hydrotreating over NiMo/γ-Al₂O₃ catalyst of castor oil methyl esters obtained by reactive extraction

In recent years, many studies have been published on the hydrotreating of non-edible vegetable oils, however, a limited number of them deal with the hydroprocessing of their corresponding fatty acid methyl esters for the productions of renewable fuels. In this study is outlined the production of renewable fuels from castor bean seeds (Ricinus communis L.) in two stages, the first one is to obtain the respective castor oil methyl esters by reactive extraction and the second one is to apply the hydrotreating process to these methyl esters by using a commercial NiMo/γ-Al₂O₃ catalyst in an isothermal batch reactor. A method was used to characterize the feedstock and the hydrotreating products from their TGA data by applying a proposed correlation equation for converting thermogravimetric measurements into simulated distillation results. Then, these estimated simulated distillation curves were used to obtain finally their characterization by composition based on real components. A chemical reaction network of four lumps along with its lumped kinetic model representing the hydrotreating of castor oil methyl esters was obtained from experiments conducted in a batch reactor operating under isothermal conditions at 395, 410, and 425 °C, 50 barg, and with reaction times from 2 to 4 h, and it was found that at severe operating conditions the yield and product selectivity of kerosene fraction increases, therefore, in order to obtain a higher production of renewable diesel fraction in this reaction system, the hydrotreating reaction time and temperature must be moderate.