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Hydrodesulphurization of dibenzothiophene on NiMoS catalysts: Impact of the carbon support on the reaction kinetics
Author(s) -
Alamoudi Majed A.,
Smith Kevin J.
Publication year - 2019
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23403
Subject(s) - dibenzothiophene , hydrodesulfurization , catalysis , microreactor , inorganic chemistry , chemistry , activated carbon , chemical engineering , organic chemistry , adsorption , engineering
The hydrodesulphurization (HDS) activity of nickel molybdenum sulphided catalysts supported on activated carbon (NiMoS/AC), activated petroleum coke (NiMoS/APC), and conventional alumina (NiMo/γ‐Al 2 O 3 ) have been compared using dibenzothiophene (DBT) as a model reactant. The reactions were carried out in a slurry‐phase batch microreactor at different reaction times (30–120 min) and temperatures (588–638 K) and a fixed H 2 pressure (4.8 MPa). The NiMoS/APC catalyst had higher dispersion than the NiMoS/AC catalyst, resulting in a higher DBT conversion activity per gram of catalyst on the NiMoS/APC catalyst. However, similar activities were obtained on both catalysts when accounting for the NiMoS dispersion. The NiMoS/APC activity was marginally lower than the NiMoS/γ‐Al 2 O 3 commercial catalyst, suggesting that activated petcoke is a promising support for NiMoS catalysts. The pseudo 1 st order rate constants for both the direct desulphurization (DDS) and hydrogenation (HYD) reaction pathways were of similar magnitude on the NiMoS/APC catalyst, as were the apparent activation energies. Hence the selectivities for HYD versus DDS were favoured equally on the NiMoS/APC, unlike on NiMoS/Al 2 O 3 where the DDS of DBT is favoured, or the NiMoS/AC where the DDS of DBT is favoured at higher temperatures (> 603 K). The results of this study demonstrate that raw petcoke derived from Canadian oilsands can be converted to a useful catalyst support for hydrotreating catalysts that have high NiMoS dispersion and HDS activity, comparable to that of a commercial NiMoS/Al 2 O 3 catalyst.