Dielectric Properties of Asphaltene Solutions: Solvency Effect on Conductivity

Lesaint, Cédric; Simon, Sébastien; Lesaint, Caterina; Glomm, Wilhelm R.; Berg, Gunnar; Lundgaard, L.E.; Sjöblom, Johan

doi:10.1021/ef3013129

Cited by 17 publications

(13 citation statements)

References 35 publications

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“…In addition to being a technique with a relatively short path, most of the published studies on mixtures are reduced to binary systems. To the authors' knowledge, only a few of them address mixtures with more than two components [47,48,56,68]. It is clear that the application of the technique to samples of such complexity, such as diesel fuel and biodiesel, is a challenge.…”

Section: Excess Complex Dielectric Constantmentioning

confidence: 99%

Relaxation Dynamics of Ethanol and N-Butanol in Diesel Fuel Blends from Terahertz Spectroscopy

Patiño-Camino

Cova-Bonillo

Rodríguez–Fernández

et al. 2021

J Infrared Milli Terahz Waves

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Binary blends of ethanol-diesel, n-butanol-diesel, ethanol-biodiesel, and n-butanol-biodiesel have been analyzed with terahertz time-domain spectroscopy in a full range of concentrations and at room temperature. The real and imaginary parts of the complex dielectric constant of the blends were obtained from the spectra and fitted to the Debye model at low volume concentrations (up to 7.5% for ethanol in diesel and up to 20% for butanol in diesel, ethanol in biodiesel, and butanol in biodiesel blends), considering the number of relaxation processes recommended in the literature for each pure component (single for diesel, double for biodiesel, and triple for alcohols). The results indicate that the faster relaxation time in low alcohol mixtures is longer than in pure alcohols. This relaxation time increases as the alcohol content increases. The excess of the real and of imaginary parts of the dielectric constant were individually determined. The analysis of such excess and of its different contributions (volume, contrast, and interactions) suggests that the intermolecular interactions between the different components of the blends dominate the relaxation dynamics in each pseudo-binary system. Ethanol was found to move blends further away from ideal behavior than n-butanol. In fact, these latter blends showed the most ideal behavior, suggesting that the length of the alcohol carbon chain plays an important role. This information allows a possible link between the nonlinear behavior of the physicochemical properties of the blends (e.g., viscosity and surface tension) and the molecular interactions between their constituent molecules. This relation could have direct application for monitoring the fuel composition and quality in the vehicle control systems.

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Section: Excess Complex Dielectric Constantmentioning

confidence: 99%

Relaxation Dynamics of Ethanol and N-Butanol in Diesel Fuel Blends from Terahertz Spectroscopy

Patiño-Camino

Cova-Bonillo

Rodríguez–Fernández

et al. 2021

J Infrared Milli Terahz Waves

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“…It shows that the n ‐hexane addition can enhance the free water content in the oil sands mixture. The previous investigations have proven that an increasing free water content could enhance the soil mixtures’ permittivity . Hence, the dynamic change of free water content induced by the addition of n ‐hexane provides an explanation for the permittivity behaviours of n ‐hexane/oil sands mixtures.…”

Section: Resultsmentioning

confidence: 92%

Determination of the permittivity of n‐hexane/oil sands mixtures over the frequency range of 200 MHz to 10 GHz

Ahmadloo

2018

Can J Chem Eng

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Combined electromagnetic (EM) heating and solvent injection has been recently proposed to recover bitumen from oil sands due to its great environmental friendliness. The permittivity of oil sands with the presence of solvent is a crucial property for the design, evaluation, and optimization of this process. In this study, we use the open-ended coaxial probe method to measure the permittivity of oil sands over the frequency range of 200 MHz to 10 GHz. Results of the permittivity of the constituents of oil sands reveal that water is a major dielectric contributor; no relaxation phenomenon has been found for bitumen, sand, and n-hexane over the tested frequency range. Also, the results for the oil sands mixtures show that water content is crucial for the permittivity of oil sands; both the dielectric constant and loss factor are enhanced with an increasing water content. With the addition of n-hexane, the permittivity of bitumen slightly changes and fluctuates between the dielectric values of pure bitumen and n-hexane. As for the n-hexane/oil sands mixtures, the added n-hexane induces the asphaltene aggregation/flocculation, affecting the interaction between water and asphaltene and leading to an enhanced free water content in the oil sands. Consequently, the permittivity of oil sands significantly increases after n-hexane addition. Based on the experimental data, we evaluate the prediction accuracy of commonly used mixing models. A modified Lichtenecker-Rother model considering effective water saturation is proposed to accurately characterize the permittivity of n-hexane/oil sands mixtures. The obtained data and correlations can be useful when experimental data are missing.

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“…Electrical conductivity (EC) represents the ability of material to conduct an electric current. EC measurements have been utilized to understand behavior of asphaltenes alone and their interactions with other crude oil components in different solvents. ,− It has been shown that the crude oils rich with asphaltenes had a higher conductivity than other oils . The conductivity of crude oil solution was suggested to be governed not only by the amount of asphaltenes in the crude oil but also by their aggregation state and mobility.…”

Section: Electrical Properties Of Asphaltenesmentioning

confidence: 99%

“…The crude oil diluted with heptane showed a lower conductivity than those same oils diluted with the same amount of toluene. The observation was ascribed to more pronounced aggregation of asphaltenes in heptane compared to toluene and the formation of larger aggregates. , Later, by comparing the DC conductivities at various concentrations of asphaltenes, it was concluded that the most aromatic components of crude oils are captured by toluene, in which they contribute to high conductivity, while the fractions of crude oils that form nanoaggregates are captured by n -heptane and are characterized by low conductivity . It has been also suggested that electrical conductivity may originate from a rapid charge exchange between asphaltene colloidal particles and that the self-association of asphaltenes in crude oil can be facilitated by the electron transfer between asphaltene molecules …”

Section: Electrical Properties Of Asphaltenesmentioning

confidence: 99%

“…Both characteristics of the asphaltenes (e.g., elemental composition, functional groups, surface charge, aggregate size) and process parameters such as current type (DC/AC), potential applied, diluent type, dilution ratio, and residence time can influence the electrophoresis of asphaltenes, i.e., their movement in the electric field. , For the first time, Wright and Minesinger (1963) employed an electrophoresis method to study asphaltenes. They established that asphaltenes carry a positive charge, and this charge is sufficient to induce particle mobility in ordinary electrophoresis .…”

Section: Electrical Properties Of Asphaltenesmentioning

confidence: 99%

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Review of Asphaltenes in an Electric Field

2021

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Asphaltenes are regarded as troublesome components of crude oils as their precipitation and deposition inside production wells and downstream infrastructure often result in a reduction of production capacity and, in critical cases, production shut-in. It has been shown that asphaltene deposition on conductive surfaces can be controlled by the application of an electric field. The electric field has been used to either inhibit or accelerate asphaltene deposition. This paper reviews asphaltene behavior in an electric field. It describes the structure and electric properties of asphaltenes as well as their electrokinetic behavior. State-of-the-art asphaltene electrodeposition and separation from both model and crude oils using electric fields are also discussed. The influence of parameters such as asphaltene chemistry, crude oil composition, pH, electric field strength, and flow conditions on the asphaltene electrodeposition process is addressed, and the effect of asphaltene interactions with themselves and other crude oil components is evaluated. A comprehensive literature survey reported the electrodeposition on both positive and negative electrodes, which suggests the complexity of the process. It has been shown that asphaltene charges can be tailored by changing the process parameters. Because of the high energy efficiency and relatively simple process, asphaltene electrodeposition is currently a key solution for removal of asphaltenes from crude oils. This review also highlights the main challenges and knowledge gaps associated with the asphaltene electrodeposition process.

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Dielectric Properties of Asphaltene Solutions: Solvency Effect on Conductivity

Cited by 17 publications

References 35 publications

Relaxation Dynamics of Ethanol and N-Butanol in Diesel Fuel Blends from Terahertz Spectroscopy

Relaxation Dynamics of Ethanol and N-Butanol in Diesel Fuel Blends from Terahertz Spectroscopy

Determination of the permittivity of n‐hexane/oil sands mixtures over the frequency range of 200 MHz to 10 GHz

Review of Asphaltenes in an Electric Field

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