Characterization of Crude Oils and the Precipitated Asphaltenes Fraction using UV Spectroscopy, Dynamic Light Scattering and Microscopy

Abstract

Analysis of crude oil composition provides important information that impacts on the recovery, handling, and transportation of hydrocarbons. Crude characterization also provides data in the analysis of geochemistry of the source of origin. Crude oil characterization by optical methods is usually diicult because of its dark color; however, those characterizations are crucial because they give information that can afect some analysis procedures. Ultraviolet-visible (UV-vis) spectroscopy is a simple and practical technique that allows the characterization of crude oil through dilution in solvents. A comparative study of crude oil solutions contrasted with their asphaltene fractions was performed. Each solution was analyzed in triplicate, on a UV-vis spectrophotometer. Calibration curves for both raw solutions showed no signiicant variations, indicating stability. Additionally, the results of dispersion and migration phenomena indicated stability only for crude oil solutions. The aggregate size dispersion was diferent for each type of crude and varied with respect to time. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the type of morphology present for each type of asphaltene.

The Asphaltenes: State-of-the-Art Applications and Future Perspectives in Materials Science

“…Furthermore, the absorption coefficients of asphaltenes exhibited variability across their diverse molecular compositions. Banda-Cruz et al identified the UV signals of benzenic, naphthenic, and Soret compounds, which correspond to petroleum porphyrins in crude oil and extracted asphaltenes. Derivative UV–vis spectroscopy was employed to validate the existence of an archipelago-type architecture within the asphaltene mixture, and the absorption spectrum identified benzenic compounds, naphthenic compounds, aromatic chromophores, and vanadium petroleum porphyrins .…”

Photocatalytic performance of textiles coated with titanium dioxide-reduced graphene oxide system for degradation of crude petroleum under similar solar irradiation

“…p à electronic transitions in conjugated aromatic structures [72]. The exponential decay profile is due to the intense light scattering in wavelength less than 400 nm caused by asphaltene macromolecules present in the sample [73]. In addition, a possible explanation for the slight increase in the fraction of light absorbed after 40 h of irradiation involves a process of evaporation of the compounds with lower boiling points.…”

Suppression of Asphaltene Adsorption and Deposition in Porous Media

“…It is found to be sensitive to many variables, such as the source of asphaltenes, quality of the solvent, and properties of the adsorbent. Researchers have employed a variety of experimental techniques to characterize asphaltene adsorption such as contact angle measurements, − AFM, , NIR/UV–vis spectroscopy, − quartz crystal microbalance (QCM) gravimetry, , ellipsometry, and electrokinetic measurements. , The source of asphaltenes determines the chemical functionalities of the asphaltene molecules, which impact the extent of asphaltene adsorption on the same adsorbents. Two studies, conducted by Pernyeszi and Marczerski, may be used to highlight how these geographic differences result in different adsorption behavior onto various clay minerals. , Both researchers studied the static adsorption of asphaltenes dissolved in toluene onto different clay minerals, such as kaolinite, illite, and montmorillonite, using UV–vis spectroscopy.…”