Hydrodesulfurization of Model Naphtha using NiMo/Al2O3 Nanocatalyst Prepared by Supercritical Deposition

فاقد چكيده

The synthesis of NiMo/Al2O3 nanocatalyst (NiMo-SCF; 3.2 wt% Ni and 8.2 wt% Mo) via supercritical CO2–methanol deposition and conventional wet co-impregnation (NiMo-IMP; 3.1 wt% Ni and 8.3 wt% Mo) was investigated. The characterization of both catalysts by adsorption–desorption of nitrogen, oxygen chemisorptions and XRD indicated that Ni and Mo highly dispersed on the Al2O3 support. The hydrodesulfurization of fuel model compound, dibenzothiophene, was used in the evaluation of the NiMo-SCF catalyst versus the commercial catalyst (NiMo-COM; 2.2 wt% Ni and 9.3 wt% Mo). The results of activity of the NiMo-SCF nanocatalyst in the hydrodesulfurization of dibenzothiophene demonstrated higher conversion for the NiMo-SCF nanocatalyst in contrast to commercial catalyst. The kinetic analysis of the reaction data was carried out to calculate the reaction rate constant of the synthesized and commercial catalysts in the temperature range of 543-603 K. The reaction rate constants at 603 K for the NiMo-SCF nanocatalyst and the NiMo- COM one were calculated to be 4.96*10-5 and 2.42*10-5 (mol /g cat. min), respectively. Moreover, the newly developed nanocatalyst is less inhibited than the commercial catalyst by aromatics such as toluene.