Could the Asphaltene Solubility Class Index Be Used as the “Wax Appearance Temperature” of Asphaltenes? Illustration through the Study of the Polydispersity of PetroPhase 2017 Asphaltenes

Passade-Boupat, Nicolas; Gingras, Jean-Philippe; Desplobins, Carole; Zhou, Honggang

doi:10.1021/acs.energyfuels.7b02779

Cited by 20 publications

(21 citation statements)

References 29 publications

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“…The asphaltenes of AK also have the lowest ASCI. As mentioned in the experimental section, ASCI quantifies the solubility class of asphaltenes . The higher the ASCI, the more stable the asphaltenes.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The total acid number (TAN) and total base number (TBN) were measured according to the standard methods (ASTM D664 and ASTM D2896, respectively). The Asphaltene Solubility Class Index (ASCI) was determined with a specific method developed by TotalEnergies . This index indicates the amount of n -heptane in a n -heptane/toluene mixture that leads to the precipitation of asphaltenes at infinite dilution of the crude oil.…”

Section: Methodsmentioning

confidence: 99%

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Extraction of Crude Oil Endogenous Surfactants by an Optimum Three-Phase Microemulsion System: Relation between Interfacial Behavior and a Molecular Fingerprint Obtained by Ultrahigh-Resolution Mass Spectrometry

et al. 2021

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A novel method is described to extract crude oil surface active species. It is based on the formation of balanced three-phase microemulsions (optimum Winsor III systems) with a well-defined temperature-sensitive nonionic surfactant. The crude oil surface-active species are concentrated in the middle-phase microemulsion, which is separated. The interfacial material is then recovered in the surfactant-rich aqueous phase after cooling. This method was applied to five crude oils and the interfacial materials were then analyzed by Fourier transform ion cyclotron resonance mass spectroscopy (FT-ICR MS). This novel extraction method compares well with the established “wet-silica” method, as evidenced by the analysis in the negative electrospray ESI(−) mode of the interfacial materials of the same crude extracted by the two methods. The analytical data have been related to the interfacial activity of the crude oils, namely, their tendency to form stable emulsions with water or viscous phases in surfactant/oil/water systems at equilibrium, and to their equivalent alkane carbon numbers (EACN). The interfacial materials are confirmed to be responsible for the increased stability of water-in-oil emulsions.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Extraction of Crude Oil Endogenous Surfactants by an Optimum Three-Phase Microemulsion System: Relation between Interfacial Behavior and a Molecular Fingerprint Obtained by Ultrahigh-Resolution Mass Spectrometry

et al. 2021

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“…This conclusion is valid for the experimental definition of asphaltenes used in this study (insoluble in n-hexane). Owing to the asphaltene polydispersity, 45 other procedures to remove asphaltenes could have perhaps led to different results. Naphthenic acids were also removed from the crude oil U to prepare U-NA.…”

Section: Resultsmentioning

confidence: 99%

Screening of Inhibition of Calcium Naphthenate Deposition in Crude Oil

et al. 2021

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One of the initial steps in calcium naphthenate deposition is the reaction between ARN and Ca 2+ leading to the formation of an interfacial gel. After growing, this gel will form calcium naphthenate deposits that are a threat for irregularities in crude oil production and processing. It has been previously shown that crude oil components such as asphaltenes and naphthenic acids can weaken and inhibit the formation of the interfacial gel. Based on this observation, the inhibition efficiency of four crude oils is compared. The variations of interfacial tension (IFT) and interfacial dilational modulus E′ of ARN solution (concentration = 10 μM) in contact with Ca 2+ -containing aqueous solution (pH = 8) with varying crude oil concentration allow us to define a parameter characterizing the interfacial gel inhibition efficiency of crude oils to compare the systems with each other. The determined inhibition efficiency order of crude oils is not directly related to the total asphaltene and naphthenic acid contents in the crude oils and, therefore, cannot be directly predicted by performing simple chemical analysis of the oils. By selectively removing asphaltenes and/or naphthenic acids, it was found that naphthenic acids are the most prevalent inhibitors followed by asphaltenes in the tested crude oils. Other compounds present in crude oil also have a weak inhibition activity on the ARN/Ca 2+ interfacial gel. Finally, bottle tests were performed to upscale the results obtained at the interfacial scale. Bottle tests were performed at an ARN concentration 10 times higher than that used for IFT and interfacial rheology measurements. The tests indicate the presence of a soft solid material formed by the reaction between ARN and Ca 2+ even in the presence of the crude oil that was found to have the highest interfacial gel inhibition efficiency. This apparent contradiction is not understood at the moment, and hence, a better understanding of the ARN/ Ca 2+ system is required to extrapolate the results obtained at the interface to bigger scales.

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“…All the studied solutions were made by dispersing the extracted asphaltenes in decane/toluene mixtures under vigorous stirring during 72 h. We note that TR asphaltenes precipitate in decane/toluene mixtures from 50 wt% in decane and MO asphaltenes precipitate from 40 wt% in decane. TR asphaltenes correspond to the "precipitated asphaltenes from crude oil A" which polydispersity in solubility is described in detail elsewhere [21]. The precipitation rates were determined using the Asphaltenes Solubility Class Index method (ASCI) previously developed [21].…”

Section: Crude Oil Model Solutions Preparationmentioning

confidence: 99%

“…TR asphaltenes correspond to the "precipitated asphaltenes from crude oil A" which polydispersity in solubility is described in detail elsewhere [21]. The precipitation rates were determined using the Asphaltenes Solubility Class Index method (ASCI) previously developed [21]. This methodology is based on the precipitation threshold of asphaltenes in different alkane/toluene mixtures which alkane weight percentage varies from 0 to 100 wt% by 5 wt% steps.…”

Section: Crude Oil Model Solutions Preparationmentioning

confidence: 99%

Asphaltenes at Oil/Gas Interfaces: Foamability Even with No Significant Surface Activity

Arangalage

Gingras

Passade-Boupat

et al. 2018

Colloids and Interfaces

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In the oil industry, oil foams can be found at different steps from the crude oil treatment to the gas stations. Their lifetime can sometimes reach several hours and be much longer than the residence times available for gas/liquid separation. However, the conditions of formation and stability of such foams have been poorly studied in the literature, in contrast to the foamability of aqueous systems. On the fields, it is currently observed that crude oils enriched with asphaltenes form particularly stable foams. In this work, we have studied the influence of asphaltenes on the foamability of oil mixtures. All the experiments were performed on model systems of crude oils, that-is-to-say decane/toluene mixtures containing asphaltenes at concentrations ranging from 0.01 to 5 wt%. We in particular demonstrate that, within the investigated concentration range, asphaltenes from two different wells do not have any significant surface active properties despite their contribution to the foamability of oil mixtures. We show that the formation of an asphaltene layer at the interface with air that has been evidenced in the past results from solvent evaporation. Using a recently developed experiment based on the Marangoni effect with our model oils, we demonstrate that asphaltenes are not surface active in those oils. We further characterize the oil foamability by measuring the lifetime of the foam formed by blowing nitrogen through the liquid in a column. At concentrations larger than 1 wt%, asphaltenes significantly enhance the foamability of the oil mixtures. Moreover, the closer the asphaltenes are to their limit of precipitation the larger the foamability. However, we evidence that the oil mixtures themselves foam and we show the importance to consider that effect on the foamability. In addition, we observe that the foamability of the asphaltenes solutions unexpectedly varies with the initial height of the liquid in the column. We suggest that, although not significantly modifying the surface tension, the asphaltenes could be trapped at the oil/gas interface and thus prevent bubble coalescence.

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Could the Asphaltene Solubility Class Index Be Used as the “Wax Appearance Temperature” of Asphaltenes? Illustration through the Study of the Polydispersity of PetroPhase 2017 Asphaltenes

Cited by 20 publications

References 29 publications

Extraction of Crude Oil Endogenous Surfactants by an Optimum Three-Phase Microemulsion System: Relation between Interfacial Behavior and a Molecular Fingerprint Obtained by Ultrahigh-Resolution Mass Spectrometry

Extraction of Crude Oil Endogenous Surfactants by an Optimum Three-Phase Microemulsion System: Relation between Interfacial Behavior and a Molecular Fingerprint Obtained by Ultrahigh-Resolution Mass Spectrometry

Screening of Inhibition of Calcium Naphthenate Deposition in Crude Oil

Asphaltenes at Oil/Gas Interfaces: Foamability Even with No Significant Surface Activity

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