Structural Group Analysis of Residues From Athabasca Bitumen

Gray, Murray R.; Choi, J.H.K.; Egiebor, Nosa O.; Kirchen, R. P.; Sanford, Emerson C.

doi:10.1080/08843758908962259

Cited by 6 publications

(6 citation statements)

References 8 publications

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“…Our analysis indicated that although the number of alkyl side chains on aromatic rings decreased, the average chain length remained constant (Figure 6). This observation was consistent with previous 13 C NMR analysis of coked residues, 8 but it contradicts the data of Zhao et al, 9 who presented an index that suggested a significant drop in the length of side chains with a single stage of coking. Model compound studies on dealkylation of alkyl-pyrenes and alkyl-benzenes showed that dealkylation was the preferred pathway, with less cracking of the side chain to give shorter chains, [26][27][28][29] consistent with the present results.…”

Section: Discussionsupporting

confidence: 87%

“…A structural analysis of coker recycle material was done by Kirchen et al 7 and Gray et al 8 A combined coker recycle stream, consisting of condensed recycled residue from the coker and unconverted residue, was compared to feed bitumen, atmospheric residue (343 °C+), and vacuum residue (427 °C+). An analysis of the coker recycle showed that there was a significant decrease in the total concentration of paraffinic groups compared to topped fresh bitumen.…”

Section: Introductionmentioning

confidence: 99%

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Quality of Distillates from Repeated Recycle of Residue

et al. 2002

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The yields of gas, liquid, and coke from the coking of Athabasca vacuum residue were determined as a function of conversion of the residue. High conversion was achieved by subjecting the unconverted residue to repeated coking steps. The cumulative yield of liquid increased by 12% from stage 1 of coking, where 80% residue conversion was obtained, to stage 3 where over 97% cumulative residue conversion was obtained. The quality of the distillates obtained at each stage deteriorated based on the concentrations of nitrogen and polyaromatic hydrocarbons. Although coking reactions resulted in a significant decrease in the number of paraffinic chains, the average chain length remained constant. A mass balance showed that the aromatic carbon increased in the first coking step, then remained constant.

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Quality of Distillates from Repeated Recycle of Residue

et al. 2002

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“…However, Fe-based unsupported catalysts showed similar behaviour to MoO 3 in terms of removal of nitrogen. The nitrogen content was 0.2 wt % (FeS) and 0.14 wt % (Fe 2 O 3 ), respectively and these results are similar to those of Gray et al 69 .…”

Section: Effect Of Fe-based Catalystssupporting

confidence: 91%

“…These results are consistent with the literature, where Gray et al69 reported that nitrogen compounds such as pyrroles are much less reactive which can lead to the accumulation of nitrogen compounds during the upgrading process. However, MoS 2 reduced the nitrogen amount by 46% to below 0.08 wt % in feed oil.…”

supporting

confidence: 95%

Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading

Al-Marshed

Hart

Leeke

et al. 2015

Ind. Eng. Chem. Res.

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Ultradispersed particles of size less than 100 nm for in situ catalytic upgrading have been reported to outperform the augmented catalytic upgrading achieved by incorporating pelleted refinery catalyst to the horizontal production well of the THAI process. Hydroconversion of heavy oil was carried out in a stirred batch reactor at 425˚C, 50 bar (initial H 2 pressure), 900 rpm and 60 min reaction time using a range of unsupported transition metal (Mo, Ni and Fe) catalysts. The effect of metal nanoparticles (NPs) was evaluated in terms of product distribution, physical properties and product quality. The produced coke and recovered catalysts were also studied. The levels of API gravity and viscosity of the upgraded oils observed with the NPs was approximately 21˚API and 108 cP compared with thermal cracking alone (24˚API and 53.5 cP), this moderate upgrade with NPs is due to the lack of cracking functionality offered by supports such as zeolite, alumina or silica. However, it was found that the presence of dispersed NPs significantly suppressed coke formation 4.4 wt% (MoS 2 ), 5.7 wt% (NiO) and 6.8 wt% (Fe 2 O 3 ) compared to 12 wt% obtained with thermal cracking alone. The results also showed that with dispersed unsupported metal NPs in sulfide form the middle distillate (177-343 ˚C) of the upgraded oil was improved particularly MoS 2 which gave 50 wt% relative to 43 wt% (thermal cracking) and 28 wt% (feed oil). The middle distillate yields for Fe 2 O 3 and NiO are 47 wt% and 49 wt%, respectively. Hence, iron and nickel-based unsupported NPs showed similar activity when compared to MoS 2 . The cost and availability of iron-based catalysts compared to Ni and Mo counterpart for heavy oil upgrading are advantages that may justify its preference.Furthermore, the X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis showed that introducing dispersed catalysts to the upgrading helped to produce sponge-type coke which could be used as industrial fuel compared to shot-type obtained upon thermal cracking.

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“…The total product was fractionated into boiling point fractions to analyze the unconverted vacuum residue fraction in greater detail. − In the work reported here, the total product was separated into four fractions of different boiling point ranges, initial boiling point (ibp) −176, 176−343, 343−525, and +525 °C. The objective was to examine how changes made to the catalyst properties affected the characteristics of the individual product fractions.…”

Section: Introductionmentioning

confidence: 99%

Product Fractions Obtained by Hydrocracking Vacuum Residue from Athabasca Bitumen Using Bimodal Catalysts of Varying Macropore Volume

Ternan

1998

Energy Fuels

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Residue hydrocracking catalysts containing 0%, 15%, 20%, 25%, and 30% of a nonconventional alumina component that has very large (0.1−100 μm) macropores (MAP) were prepared. Their performance was compared with a commercial bimodal catalyst that was used as a standard. When compared to the standard reference catalyst and the other MAP catalysts, the 15% macropore (MAP) alumina catalysts produced greater +525 °C conversion, greater yields of distillates, and greater total product HDS, HDN, HDM, and MCR conversions. The +525 °C conversions of several MAP catalysts exceeded that obtained in a thermal experiment without a catalyst. This indicates that the properties of a residue hydrocracking catalyst can enhance conversions beyond that obtained by thermal reactions alone. All of these effects were correlated with the mesopore surface area of the used catalysts. This was the surface area of the catalyst in its working state which was contained in pores large enough for residue molecules to enter. For the cracking reaction (+525 °C conversion) the presence of macropores in the catalyst diminished the influence of diffusion, so that the MAP catalyst results correlated with surface area. For the hydrogenation reaction (H/C ratio) the MAP catalyst results also correlated with surface area. However, catalysts with micropores produced larger H/C ratios. Hydrogen, dissociated in the micropores, may have reacted with small hydrogen transfer molecules (naphthalene − tetralin) which may have transferred the hydrogen to residue molecules outside of the micropores. The additional hydrogenation in micropores may have compensated for diffusional restrictions. For the MAP catalysts, the other reactions HDS, HDM, and MCR conversion, showed the same trends as the H/C ratio, suggesting that hydrogenation was the rate-limiting step for these reactions.

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Structural Group Analysis of Residues From Athabasca Bitumen

Cited by 6 publications

References 8 publications

Quality of Distillates from Repeated Recycle of Residue

Quality of Distillates from Repeated Recycle of Residue

Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading

Product Fractions Obtained by Hydrocracking Vacuum Residue from Athabasca Bitumen Using Bimodal Catalysts of Varying Macropore Volume

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