Hydrotreating of heavy vacuum gas oil (HVGO) on molybdenum and tungsten nitrides catalytic phases

Melo-Banda, J.A.; Domínguez, José Manuel; Sandoval-Robles, G.

doi:10.1016/s0920-5861(00)00569-1

Cited by 19 publications

(15 citation statements)

References 3 publications

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“…They compared unsupported and g-Al 2 O 3 -supported Mo 2 N and W 2 N with a commercial CoMo/Al 2 O 3 for hydroprocessing of heavy vacuum gas oil. In view of the results published by Melo-Banda et al (351), low HDN activity is expected for Mo 2 N having such a high surface area. The CoMo/Al 2 O 3 catalyst was more active for HDS, while the HDN activity of the metal nitrides was superior to that of the commercial catalyst.…”

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confidence: 84%

“…VI.2.1.2.4 HDN Activity of Mo 2 N vs. Other Phases The importance of particle size and surface area on the relative HDN activity of Mo 2 N and W 2 N was indicated in the study of Melo-Banda et al (351). The activity of the unsupported W 2 N during the HDN of the vacuum gas oil was always greater than was that of the unsupported Mo 2 N. Apparently, there is an optimal particle size for which the highest HDN activity could be attained.…”

Section: Vi2123 Effect Of H 2 S On Stability Of Mo Nitridementioning

confidence: 99%

“…A study by Melo-Banda et al (351) provides direct evidence of the anomalous behavior of metal nitrides compared with conventional catalyst. They compared unsupported and g-Al 2 O 3 -supported Mo 2 N and W 2 N with a commercial CoMo/Al 2 O 3 for hydroprocessing of heavy vacuum gas oil.…”

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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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confidence: 84%

Section: Vi2123 Effect Of H 2 S On Stability Of Mo Nitridementioning

confidence: 99%

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Hydrodenitrogenation of Petroleum

Furimsky¹,

2005

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“…Transition metal nitrides have also been tested for hydrotreatments [7][8][9][10][11][12]. However, most studies in this area have concentrated on monometallic transition metal nitrides, and relatively few bimetallic nitrides have been studied.…”

Section: Introductionmentioning

confidence: 99%

A novel Ni2Mo3N/MCM41 catalyst for the hydrogenation of aromatics

Wang

Zhang

et al. 2005

Catal Lett

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Bulk and MCM41-supported Ni 2 Mo 3 N catalysts were prepared using a temperature-programmed reduction (TPR) method and characterized using XRD, TEM, ICP-AES, and N 2 adsorption analysis techniques. Their catalytic properties were measured for the simultaneous hydrogenation of p-xylene and naphthalene and compared with Ni/MCM41 and Mo 2 N/MCM41 catalysts having similar metal loadings. The results indicate that the Ni 2 Mo 3 N/MCM41 catalyst exhibits excellent deep hydrogenation activity under mild condition (T = 483 K, P = 3.0 MPa), and that it is more active than either Ni/MCM41 or Mo 2 N/MCM41 catalyst.

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“…1 To improve control of nitride properties and to extend the number of binary and ternary nitrides available, new methods are being developed using lower temperatures compared to those required by conventional solid-state methods, for example, reactions of nitrogen with the solutions of metals in liquid zinc, 2 ammonothermal synthesis, 3 solid-state metathesis, 4 or metathesis between halogenides and lithium nitride in benzene, 5 as well as pyrolysis of azide or azane precursons, 6 CVD, or ion beam sputtering. 7 Since the synthesis methods for the high surface area molybdenum nitrides were reported, 8,9 these solids have been used as the catalysts for many reactions such as ammonia synthesis, 10 hydrotreating, 11 or isomerization. 12 The synthesis conditions have a strong influence on the molybdenum nitride catalytic activity.…”

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confidence: 99%