Resistant nitrogen compounds in hydrotreated gas oil from Athabasca bitumen

Jokuty, Paula L.; Gray, Murray R.

doi:10.1021/ef00030a004

Cited by 29 publications

(21 citation statements)

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“…Its concentration hardly decreased even at the highest HDN conversions reached in this study. Analysis of the effluent by mass spectrometry showed that the refractory pyrrole benzologues were mainly 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 carbazole and tetrahydrocarbazole-species, in agreement with the literature [33][34][35] . A more detailed discussion of the molecular level analysis of the effluents is, however, beyond the scope of the present contribution and will be presented in a separate paper.…”

Section: Discussionsupporting

confidence: 90%

How Does an Acidic Support Affect the Hydrotreatment of a Gas Oil with High Nitrogen Content?

et al. 2019

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Two NiMo sulfide catalysts, supported on Al 2 O 3 and silica-alumina, respectively, were compared in the hydrotreating of a mixture of straight-run and coker gasoil. Experiments were conducted in a continuous fixed bed reactor, at 623-643K and 5 MPa. The Al 2 O 3 -supported catalyst proved to be slightly more active in HDN and significantly more active in HDS than its silica-alumina analogue. The activity trend was attributed to the inhibition provoked by the strong adsorption of basic nitrogen species. Earlier work had shown that the adsorption (and thus the inhibition) was significantly stronger on an acidic support. Our data further showed that the reactivity of neutral (pyrrole benzologues) and basic nitrogen compounds was

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Section: Discussionsupporting

confidence: 90%

How Does an Acidic Support Affect the Hydrotreatment of a Gas Oil with High Nitrogen Content?

et al. 2019

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“…For the CoMo/Al 2 O 3 catalyst, methyl substitution in the aromatic ring resulted in a marked increase in the CNH rate relative to the HYD rate, whereas substitution in the N-ring decreased both rates. Very low reactivity of 4-alkylCARs during the hydroprocessing of gas oil was indicated by Jokuty and Gray (27) and Ignatiadis et al (107) on the basis of their predominance in the secondary products. At the same time, the latter is more active for HYD.…”

Section: Iii22 Five-membered Ringsmentioning

confidence: 96%

“…The studies of Jokuty and Gray (27,28) represent another example of the diversity of N-compounds. These authors separated the basic and nonbasic fractions from the hydrotreated gas oil derived from Athabasca bitumen by delayed coking.…”

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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“…For example, Beranek, et al, have recently reported that the addition of indole or 2-methylindole to straight run fuels promotes sediment formation during storage, but addition of the 3-methylindole isomer does not (6). Similarly, lalkylcarbazoles have been reported to be the most reactive and 4-alkyicarbazoles the most resistant in HDN of the carbazole isomers (28)(29)(30) For these reasons, an analytical method which distinguishes between primary, secondary, and tertiary aromatic amines has been developed. Rigorous reaction conditions were employed to form di-and mono-trifluoroacyl derivatives of primary and secondary amines, respectively, prior to GC/MS analyses.…”

Section: R2-nh + (Cf3-c-)20 60* C R2-n-c-cf 3 + Cf2-c-o-+mentioning

confidence: 99%