Inhibition of dibenzothiophene hydrodesulfurization by di-aza heterocycles

Ho, Teh C.; Sobel, J.E.

doi:10.1007/s10562-005-2096-6

Cited by 12 publications

(6 citation statements)

References 6 publications

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“…25 Combined experimental and modeling studies have shown that organonitrogen inhibition hits the hydrogenation site much harder than the hydrogenolysis site on Al 2 O 3 -supported catalysts. 30,32 Available evidence indicates that organonitrogen species adsorb far more strongly on hydrogenation sites than on hydrofenolysis sites. 32 The implication for ultradeep HDS catalyst development is that the higher the activity for the HDS of sterically crowded dibenzothiophenes is, the stronger the response to organonitrogen inhibition.…”

Section: Competitive Adsorption In Ultradeep Hds Regimementioning

confidence: 99%

“…30,32 Available evidence indicates that organonitrogen species adsorb far more strongly on hydrogenation sites than on hydrofenolysis sites. 32 The implication for ultradeep HDS catalyst development is that the higher the activity for the HDS of sterically crowded dibenzothiophenes is, the stronger the response to organonitrogen inhibition. 33 Due to their high selectivities toward hydrogenation, most bulk sulfide catalysts are more vulnerable to organonitrogen inhibition than Al 2 O 3 -supported catalysts.…”

Section: Competitive Adsorption In Ultradeep Hds Regimementioning

confidence: 99%

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A theory of ultradeep hydrodesulfurization of diesel in stacked‐bed reactors

Ho¹

2017

AIChE Journal

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in Wiley Online Library (wileyonlinelibrary.com)Hydrodesulfurization catalysts have two types of active sites for hydrogenation and hydrogenolysis reactions. While hydrogenation sites are more active for desulfurizing refractory sulfur species, they are more susceptible to organonitrogen inhibition than hydrogenolysis sites. In contrast, hydrogenolysis sites are more resistant to organonitrogen inhibition but are less active for desulfurizing refractory sulfur species. This dichotomy is exploited to develop an ultradeep hydrodesulfurization stacked-bed reactor comprising two catalysts of different characteristics. The performance of such a catalyst system can be superior or inferior to that of either catalyst alone. A mathematical model is constructed to predict the optimum stacking configuration for maximum synergies between the two catalysts. The best configuration provides the precise environment for the catalysts to reach their full potentials, resulting in the smallest reactor and minimum hydrogen consumption. Model predictions are consistent with experimental results. A selectivity-activity diagram is developed for guiding the development of stacked-bed catalyst systems.Bottom curve: reference catalyst followed by new catalyst configuration; middle curve: mixed-bed; top curve: new catalyst followed by reference catalyst configuration.

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Section: Competitive Adsorption In Ultradeep Hds Regimementioning

confidence: 99%

Section: Competitive Adsorption In Ultradeep Hds Regimementioning

confidence: 99%

A theory of ultradeep hydrodesulfurization of diesel in stacked‐bed reactors

Ho¹

2017

AIChE Journal

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“…Several studies have reported on the HDS of model reactants to determine the kinetics of the reactions and this is a useful approach when quantifying the activity of different HDS catalysts . The reaction pathway for the HDS of DBT reported in these studies, presented in Figure , assumes two competing reaction steps for the HDS of DBT (direct desulphurization (DDS) that yields biphenyl (BP) and hydrogenation (HYD) that yields tetrahydrodibenzothiophene (THDBT)).…”

Section: Introductionmentioning

confidence: 99%

“…Subsequent hydrogenation steps yield mostly cyclohexylbenzene (CHB) and bicylcohexyl (BCH) as well as minor amounts of other partially hydrogenated intermediates, such as cyclohexenylbenzene and hexahydrodibenzothiophene, that are dependent on the reaction conditions. In several studies only CHB and BCH were detected in the product because of high selectivty to the hydrogenation route, especially at lower tempertaures . Hence a simplifed reaction network has been used to describe the HDS of DBT, based on the four kinetically important reaction steps 1–4 shown in Figure .…”

Section: Introductionmentioning

confidence: 99%

Hydrodesulphurization of dibenzothiophene on NiMoS catalysts: Impact of the carbon support on the reaction kinetics

Alamoudi¹,

Smith²

2019

Can J Chem Eng

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The hydrodesulphurization (HDS) activity of nickel molybdenum sulphided catalysts supported on activated carbon (NiMoS/AC), activated petroleum coke (NiMoS/APC), and conventional alumina (NiMo/g-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/g-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.

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“…Elimination of these heteroatoms contained in crude oils is accomplished in the presence of heterogeneous catalysts such as supported CoMo, NiMo, CoW, and NiW, for hydrodenitrogenation (HDN) [5][6][7][8][9][10], hydrodeoxygenation (HDO) and hydrodesulfurization (HDS) [11,12]. Determining the chemical nature of N, O or S compounds is very important to design appropriate catalysts.…”

Section: Introductionmentioning

confidence: 99%