Kinetic modeling of deep hydrodesulfurization of dibenzothiophenes on NiMo/alumina catalysts modified by phosphorus

• Published in: Fuel processing technology 2018-08, Vol.177, p.66-74
• Main Authors: Dorneles de Mello, Matheus, de Almeida Braggio, Flávia, da Costa Magalhães, Bruno, Zotin, José Luiz, da Silva, Mônica Antunes Pereira
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Catalysts; Dibenzothiophene; Diesel; Hydrodesulfurization; Hydrogenation; Kinetic modeling; NiMo catalyst; Parameter estimation; Phosphorus; Reaction kinetics
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2018.04.010

A series of NiMo/alumina catalysts modified with phosphorus was prepared and evaluated in a trickle-bed high-pressure flow micro-reactor. The kinetics of deep hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) was investigated based on conversion and products distribution data. The estimated parameters obtained were statistically significant, suggesting an accurate representation of the system. Phosphorus addition led to a two-fold increase in the formation of direct desulfurization over hydrogenation products for the HDS of DBT. On the other hand, the HDS of DMDBT increased mainly due to an increase in the hydrogenation route, leading to high yields of hydrogenated products. The observed phenomena were described well by the estimated parameters and may be related to an increase in metal dispersion, formation of more active sites and enhancement in Brønsted acidity in the catalyst upon phosphorus addition. •Kinetic parameters for HDS reactions with NiMoP catalysts are estimated over a wide range of conditions.•The effect of phosphorus content on kinetic parameters for each HDS reaction route is analyzed.•Phosphorus promotes both hydrogenation and hydrogenolysis pathways on HDS of DBT.•Phosphorus enhances the hydrogenation activity for the HDS of DMDBT.•HDS activity promotion by phosphorus is associated to improved dispersion and acidity.