The Phase Behavior of Athabasca Vacuum Bottoms + n-Alkane Mixtures

Zou, Xiang-Yang; Zhang, Xiaohui; Shaw, John M.

doi:10.2118/97661-ms

Cited by 4 publications

(4 citation statements)

References 21 publications

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“…Reactor. The coking experiments were performed in a variable-volume X-ray view cell 30,31 with which one can observe the phase behavior of mixtures opaque to visible and infrared light. The advantage of using this view cell as a batch hydroprocessing reactor is that one can monitor and control the phase to which catalyst pellets are exposed.…”

Section: Methodsmentioning

confidence: 99%

Impact of Multiphase Behavior on Coke Deposition in a Commercial Hydrotreating Catalyst under Sedimentation Conditions

2005

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Diverse coke deposition mechanisms and models, all supported by experimental data, have been proposed for catalytic hydrogenation processes related to heavy oil and bitumen refining. The influence of multiphase behavior on the observed deposition mode is an important but unresolved question in this literature. The model mixture Athabasca vacuum bottoms (ABVB) + decane, which is shown to exhibit L1L2V phase behavior at elevated temperatures and a commercial heavy oil hydrotreating catalyst (NiMo/γ-Al2O3) were employed in this preliminary investigation. Under sedimentation conditions, the impact of phase behavior, per se, on the amount of coke deposited on and within catalyst pellets and the distribution of coke within catalyst pellets was found to be a secondary one despite the differences in the physical properties of the solvent-rich L1 phase and asphaltene-rich L2 phase. In all cases, the exterior surfaces of pellets were coated with a thick nanoporous coke layer. The ratio of pore surface area to pore volume also increased with the extent of reaction in all cases, indicating that larger pores are filled in part or plugged in preference to smaller ones. Observed differences in the properties of coked catalyst exposed to the L1 and L2 phases and to multiphase environments are attributed to differences in the asphaltene aggregate size distribution in the two phases and to multiphase hydrodynamic effects.

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Section: Methodsmentioning

confidence: 99%

Impact of Multiphase Behavior on Coke Deposition in a Commercial Hydrotreating Catalyst under Sedimentation Conditions

2005

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“…Adherent deposits observed for AVR + pentane mixtures may arise from asphaltene or asphaltene-rich deposits because asphaltene precipitation has been shown to be largely reversible, − and asphaltenes and asphaltene-rich deposits undergo transitions to a liquid in a relevant temperature interval. ,− In this exploratory experimental work, deposits formed from AVR + pentane mixtures are investigated using well-defined acidic (FeS, SiO 2 ,, ) and basic (Fe 2 O 3 /FeOOH/FeO ,, and Ni/NiO/NiOH , ) substrates. The impacts of surface properties, mixture phase behavior, and mixture composition on deposit thickness and deposit composition are evaluated using XPS.…”

Section: Introductionmentioning

confidence: 99%

“…Adherent deposits observed for AVR þ pentane mixtures may arise from asphaltene or asphaltene-rich deposits because asphaltene precipitation has been shown to be largely reversible, [57][58][59][60][61] and asphaltenes 62 and asphaltene-rich deposits undergo transitions to a liquid in a relevant temperature interval. 59,[63][64][65][66] In this exploratory experimental work, deposits formed from AVR þ pentane mixtures are investigated using well-defined acidic (FeS, 41 SiO 2 42,67,68…”

Section: Introductionmentioning

confidence: 99%

Sorption of Athabasca Vacuum Residue Constituents on Synthetic Mineral and Process Equipment Surfaces from Mixtures with Pentane

2010

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Deposition of organic material on mineral and process equipment surfaces poses production, transport, and refining challenges for the petroleum industry. For high-asphaltene content hydrocarbon resources, such as bitumen, deposits are frequently assumed to be asphaltene rich. In this work, deposits formed from Athabasca vacuum residue (AVR) comprising 32 wt % asphaltenes + pentane mixtures on acidic (FeS, SiO2) and basic (Fe2O3/FeOOH/FeO, Ni/NiO/NiOH) substrates are analyzed using X-ray photoelectron spectroscopy. Control experiments with pure compounds are used to confirm experimental protocols and to address substrate contamination, which interferes with deposit composition measurements, if the organic deposit is thin or surface coverage is partial. Substrate properties are found to affect both deposit thickness and deposit composition. On basic substrates, deposits are thinner and are enriched in sulfur relative to AVR. On acidic substrates, deposits are thicker and are sulfur deficient relative to AVR, even though asphaltenes, which are rich in sulfur, sorb more strongly on acidic substrates in the absence of competition from other species. Deposit composition was also found to be invariant with the composition and phase behavior of the AVR + pentane mixtures. These results were not expected.

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“…Here the potential for selectively separating Athabasca vacuum bottoms (ABVB) using alkane solvents is assessed with the above targets in mind. The multiphase behavior of ABVB + alkane solvents was investigated using our X-ray view-cell technology. , Detailed phase diagrams for these systems, exhibiting diverse multiphase behaviors, comprise a companion paper . Figure illustrates the complexity of the phase behaviors observed and the phase-naming scheme employed.…”

Section: Introductionmentioning

confidence: 99%

Selective Rejection of Inorganic Fine Solids, Heavy Metals, and Sulfur from Heavy Oils/Bitumen Using Alkane Solvents

Zou

Dukhedin-Lalla

Zhang

et al. 2004

Ind. Eng. Chem. Res.

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Bitumen and heavy oil + alkane solvents exhibit complex phase behaviors. For example, organic components of these materials can be solubilized and inorganic solids dispersed into a high-pressure gas phase. Conversely, they can also be partitioned into as many as three bulk phases: a gas phase, a liquid phase that is largely free of inorganic solids, and a phase comprising essentially all of the inorganic solids and a small fraction of the organic material. The outcome depends on the temperature, pressure, and solvent-to-feed ratio. Mass balance results for a screening survey for Athabasca vacuum bottoms (ABVB) + alkane solvents (pentane, heptane, decane, and dodecane) are reported along with a limited number of phase composition data for ABVB + pentane and dodecane mixtures. Reversible phase behavior and irreversible thermolysis conditions were considered. The key findings are that inorganic solids are readily partitioned from ABVB irrespective of the solvent and operating conditions employed, while key heavy metals, such as vanadium, require a combination of phase behavior and mild thermolysis. Sulfur- and nitrogen-containing species possess low rejection selectivities in this solvent series.

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The Phase Behavior of Athabasca Vacuum Bottoms + n-Alkane Mixtures

Cited by 4 publications

References 21 publications

Impact of Multiphase Behavior on Coke Deposition in a Commercial Hydrotreating Catalyst under Sedimentation Conditions

Impact of Multiphase Behavior on Coke Deposition in a Commercial Hydrotreating Catalyst under Sedimentation Conditions

Sorption of Athabasca Vacuum Residue Constituents on Synthetic Mineral and Process Equipment Surfaces from Mixtures with Pentane

Selective Rejection of Inorganic Fine Solids, Heavy Metals, and Sulfur from Heavy Oils/Bitumen Using Alkane Solvents

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