Ring opening and kinetics study of hydrotreated LGO on Ni-Mo carbide supported on HY and H-Beta catalysts

Pt-Ir/HY, Ni-Mo carbide/HY and Ni-Mo carbide/H-Beta catalysts were used to improve the fuel quality of Hydrotreated Light Gas Oil (HLGO). All the catalysts are well characterized by using BET, Elemental, TPR, TPD and XRD analyzers. Screening of the catalysts were done and observed that Ni-Mo carbide/HY is an effective catalyst for improvement in cetane index of HLGO. A 12 unit increase in cetane index was observed on Ni-Mo carbide/HY at 325 °C, whereas Ni-Mo carbide/H-Beta could not improve the cetane index effectively. The Pt-Ir/HY deactivates in three days even though its activity is comparable with that of Ni-Mo carbide/H-Beta. NMR analysis showed that the Ni-Mo carbide/HY catalyst improves the cetane index of the fuel by selectively converting the naphthenes to paraffins in the temperature range of 300–325 °C. Low cetane index was observed above 325 °C due to the dominance of dehydrogenation and secondary cracking reactions. Simulated distillation results indicated the presence of high percentage of naphtha fraction above 325 °C, which decrease the fuel quality due to their low cetane values. A first order kinetic model was proposed and the model was well fit with the experimental values. Arrhenius activation energies of 111, 89 and 42 kJ/g mol were observed for dehydrogenation, aromatic saturation and cracking reactions, respectively.

Environmental concerns and regulations require severe upgrading of gas oils to get clean-burning transportation fuels. Fuel quality improvement of hydrotreated LGO was studied on Pt-Ir/HY and Ni-Mo carbide catalysts supported on HY and H-Beta. 12 unit increase in the cetane index was observed at 325 °C on Ni-Mo carbide/HY. High cetane ring opening products formation was observed at 300–325 °C on Ni-Mo carbide/HY which was also confirmed by NMR and boiling point distribution results.Figure optionsDownload as PowerPoint slide