Hydroprocessing of oleic acid for production of jet fuel range hydrocarbons over Sn(1)‐Fe(3)‐Cu(13)/SiO₂‐Al₂O₃ catalyst: Process parameters optimization, kinetics, and thermodynamic study

Abstract

Hydroprocessing of vegetable oil to high‐quality jet fuel range hydrocarbons (HRJ) plays a significant role in the development of completely interchangeable substitute for conventional petroleum‐derived jet fuel and has drawn the attention of aviation experts due to its capacity to mitigate greenhouse gas emissions associated with the aviation industry. The limited performance of 1 wt. % Sn promoted Fe(3)‐Cu(13)/SiO2‐Al2O3 catalyst in our previous study has been attributed to the successive consideration of one variable at a time in its evaluation. Maximization of oleic acid conversion and selectivity of jet fuel range hydrocarbons from hydroprocessing of oleic acid over 1 wt. % Sn promoted Fe(3)‐Cu(13)/SiO2‐Al2O3 catalyst with the best combination of the process parameter involved via multivariate approach, and evaluation of kinetic and thermodynamic activation parameters is the focus of this study. Reduced cubic oleic acid conversion model and reduced quadratic jet fuel range hydrocarbons selectivity model of high significance levels, adequate precision, and high correlation coefficient were developed. Reaction temperature of 339.5°C, 1.6 MPa H2 pressure, 6.2 wt.% catalyst concentration, and 8.0 h reaction time were optimum process parameters that can maximize oleic acid conversion and selectivity of jet fuel range hydrocarbons at 98.2% and 82.2%, respectively. This process was found to be endothermic, irreversible, and nonspontaneous with 45.8 KJ/mol activation enthalpy of reaction, 0.25 KJ/mol entropy of reaction, and the reaction's Gibb's free energy of 198.8 KJ/mol at 340°C. The minimum energy required for the reaction to take place was evaluated as 50.7 KJ/mol.