Enhancing simultaneous hydrodesulfurization and hydrodenitrogenation reactions: Kinetic modeling of stacked NiMoP and CoMoP catalysts beds

• Published in: Catalysis today Vol. 443; p. 114954
• Main Authors: Nascimento, Idia Gigante, Campos Machado, Matheus da Silva, de Mello, Matheus Dorneles, Segtovich, Iuri Soter Viana, Zotin, José Luiz, da Silva, Mônica Antunes Pereira
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2025
• Subjects: 4,6-dimethyldibenzothiophene; CoMoP/Al2O3; Deep hydrodesulfurization; Kinetic modeling; NiMoP/Al2O3; Quinoline; Quinoline; CoMoP/Al2O3; Kinetic modeling; Deep hydrodesulfurization; 4,6-dimethyldibenzothiophene; NiMoP/Al2O3
• ISSN: 0920-5861
• DOI: 10.1016/j.cattod.2024.114954

Stringent environmental regulations require reducing fuel sulfur content for adequate operation of vehicle emission control systems. Deep hydrodesulfurization (HDS) removes over 99 % of sulfur compounds, including the less reactive ones like 4,6-dimethyldibenzothiophene (4,6-DMDBT). However, HDS kinetics is inhibited by compounds like H2S, nitrogenous compounds, and aromatics. This article delves into kinetic modeling of concurrent hydrodesulfurization (HDS) of 4,6-DMDBT and hydrodenitrogenation (HDN) of quinoline (Q) reactions. It explored the use of stacked beds of CoMoP and NiMoP catalysts in two configurations. The effects of temperature and weight hourly space velocity (WHSV) on conversions and product yields were investigated. Higher reaction temperatures, in addition to the expected increase of 4,6-DMDBT and quinoline overall conversions, also led to an increased in hydrogenation selectivity. Kinetic models were developed for these reactions and catalysts, and kinetic parameters were estimated using a hybrid numerical procedure. The configuration where CoMoP was the first catalyst to encounter the reaction feedstock exhibited higher conversions for both reactions. The apparent activation energies for 4,6-DMDBT HDS were 99 and 41 kJ mol−1 for NiMoP and CoMoP, respectively while for HDN, values of 62 and 68 kJ mol−1 were estimated. For the adsorption enthalpy of nitrogenous compounds, values of −59 and −40 kJ mol−1 were observed for NiMoP and CoMoP, respectively. [Display omitted] •Deep HDS of 4,6-DMDBT and HDN of quinoline was evaluated in fixed-bed reactor.•Process variables investigated with NiMoP and CoMoP stacked beds.•Estimation and statistical evaluation of kinetic parameters were performed.•Langmuir model used for NiMoP bed's HDS reaction inhibited by nitrogen compounds.•For CoMoP, Langmuir model used for HDS, power law for HDN.