Residual-Oil Hydrotreating Kinetics for Graded Catalyst Systems:  Effect of Original and Treated Feedstocks

Marafi, A.; Albazzaz, Hamza; Almarri, Masoud; Maruyama, Fumio; Absi-Halabi, † and M.; Stanislaus, A.

doi:10.1021/ef020282j

Cited by 42 publications

(45 citation statements)

References 25 publications

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“…Absi-Halabi et al (483) used a residue to study the effect of the catalyst pore size on HDS, HDN, and HDM. In the study on kinetics of HDS, HDN, HDM, HDAsph and hydrocracking of three atmospheric residues over NiMo/Al 2 O 3 and NiMoP/Al 2 O 3 catalysts Abasi-Halabi et al (485) established that the activity order was different for each feed and catalysts though order for HDV, HDNi, HDAsph, and hydrocracking was similar. Results published by Yang et al (484) were in essential agreement.…”

Section: E Furimsky and F E Massothmentioning

confidence: 99%

Hydrodenitrogenation of Petroleum

Furimsky¹,

2005

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A high level of hydrodenitrogenation (HDN) is required to achieve a desirable conversion of other hydroprocessing reactions. This results from a strong adsorption of nitrogen-containing compounds on catalytic sites that slows down the hydrogen activation process and hinders the adsorption of other reactants. Studies on model compounds and real feeds indicate that less than 50 ppm of nitrogen in the feed can poison catalytic sites. Kinetic studies determined adsorption constants of various nitrogen-containing compounds and concluded that at least four different catalytic sites are required to interpret experimental observations in contrast with a dual site site ffi concept, which only considered two sites. The advancements in experimental techniques allowed identification of products formed during very early stages of hydrodenitrogenation. These results confirmed that the removal of the amino group from saturated amines, as the last step in hydrodenitrogenation, is governed by the type of carbon to which the amino group is attached rather than the number of hydrogen atoms attached to carbon in a and b position to nitrogen Performance of conventional Co(Ni)Mo(W)/Al 2 O 3 catalysts during hydrodenitrogenation was enhanced by combination with various additives and by replacing the traditionally used g-Al 2 O 3 support with novel supports. Catalytic functionalities could be modified by using different precursors of active metals and varying conditions during preparation. Progress has been made in the development of catalysts possessing a high selectivity for hydrodenitrogenation. In this case, the nonconventional catalysts based on the carbides and nitrides of transition metals exhibited high activity and selectivity. Noble metal sulfides alone or supported on different supports were active for HDN as well. Feedstocks used for catalyst evaluation included model compounds and mixtures of model compounds as well as real feeds. The challenges in the development of catalysts for hydrodenitrogenation of heavy feeds containing asphaltenes and metals have been identified.In general, compared to Q, conversions were little affected by a methyl (Me) on the aromatic ring, while being lower for Me on the N-ring, except for 2-MeQ. It is evident that Me substitution in the 2-position had little effect on HDN over the NiMoP/Al 2 O 3 catalyst, whereas it actually enhanced the HDN rate over the CoMo/Al 2 O 3 catalyst. For both catalysts the HDN rate was suppressed in 6-MeQ and particularly in 3-MeQ and 4-MeQ. The distribution of N-containing intermediates was influenced by the ring substitution and the type of catalyst. This suggests that several factors influence the overall HDN mechanism of Qs. This should be kept in mind while analyzing differences in the networks proposed by different authors.The preceding discussion on the HDN of Q mostly referred to conventional catalysts. A number of studies on the HDN of Q were conducted over unconventional catalysts. For example, 3-and 4-MeQs were more reactive than Q over the unsupported Zr,...

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Section: E Furimsky and F E Massothmentioning

confidence: 99%

Hydrodenitrogenation of Petroleum

Furimsky¹,

2005

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“…The catalysts in the second, third, and fourth reactors contained various amounts of Ni and Mo on γ -Al 2 O 3 and performed HDM/HDN, HDS, and HDS/HDN duties, respectively. Because of proprietary agreements, only limited information on the properties of these catalysts could be given (Marafi et al, 2003a). The content of contaminants in spent catalysts is shown in Table 1, whereas surface properties of the fresh, spent, and decoked catalysts in Table 2 (Al-Dalama et al, 2003a).…”

Section: Methodsmentioning

confidence: 99%

Evidence for Autocatalysis and Its Implications for the Kinetics of Hydroprocessing of Petroleum Residues

Al-Dalama

Stanislaus

Navvamani

et al. 2014

Petroleum Science and Technology

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During hydroprocessing of residual feeds the rate of some reactions tends to increase temporarily despite the continuous deposition of coke and metals on catalyst surface. This rate increase has been attributed to catalytic effect of the contaminant metals such as vanadium and nickel in residual feeds after their deposition on catalyst surface. The portion of metals that deposited on the bare γ -Al 2 O 3 surface of the catalysts transfers the originally inactive surface to catalytically active. The increase in the rate of HDS, HDAs, and some HDM reactions could only be reconciled assuming the involvement of autocatalysis by the deposited metals.

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“…Gradation strategies have been widely adopted in the petrochemical industry to adjust the type and dosage of catalysts and form targeted catalyst combinations that meet the process requirements according to the operating conditions and reaction characteristics of the catalyst bed in a reactor. , This strategy makes it possible to adapt to changes in raw materials and product demand. The complex composition of crude oil and the range of required catalyst performance motivated the development of catalyst gradation strategies, and the treatment of real wastewater poses similar technological demands for successful photocatalysis . A gradation strategy should be suitable for solving the current problem in the application of photocatalysis to complex wastewater.…”

Section: Introductionmentioning

confidence: 99%

“…The complex composition of crude oil and the range of required catalyst performance motivated the development of catalyst gradation strategies, and the treatment of real wastewater poses similar technological demands for successful photocatalysis. 30 A gradation strategy should be suitable for solving the current problem in the application of photocatalysis to complex wastewater. However, a gradation strategy alone cannot completely solve the problem of variable wastewater composition and achieve the targeted adjustment of the photocatalyst combination and ratio.…”

Section: ■ Introductionmentioning

confidence: 99%

Treatment of Variable Complex Mixed Dye Wastewater by Photodegradation with a Photocatalyst Gradation Strategy

Tang

Gong

et al. 2021

Ind. Eng. Chem. Res.

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Photocatalysis is a promising advanced oxidation technology for treating wastewater; however, the complexity, diversity, and variability of actual wastewater make its application difficult at the current level of technology. In this work, a photocatalyst gradation strategy is proposed in which the specific photocatalysts Ag2O, NaBiO3, and BiOCl0.75Br0.25 are combined to treat the specific pollutants methyl orange, methylene blue, and rhodamine B, as well as their mixtures. The photocatalyst ratio is adjusted on the basis of big data analysis to photodegrade variable mixed dye solutions rapidly and efficiently. The results demonstrate positive synergistic effects among the photocatalysts, which can completely decolorize a 30 mg/L mixed dye solution at a ratio of 1:1:1 in 15 min. When big data analysis is applied, mixed dye solutions with random dye ratios are purified sufficiently to meet the standard using a graded photocatalyst combination based on the predictions of the trained model. This work provides a reference strategy for the treatment of complex variable wastewater.

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Residual-Oil Hydrotreating Kinetics for Graded Catalyst Systems: Effect of Original and Treated Feedstocks

Cited by 42 publications

References 25 publications

Hydrodenitrogenation of Petroleum

Hydrodenitrogenation of Petroleum

Evidence for Autocatalysis and Its Implications for the Kinetics of Hydroprocessing of Petroleum Residues

Treatment of Variable Complex Mixed Dye Wastewater by Photodegradation with a Photocatalyst Gradation Strategy

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