Inhibition of Asphaltene Precipitation by Resins with Various Contents of Vanadyl Porphyrins

Abstract

Comparative analysis of the composition and properties of heavy oils from various oil fields has revealed an inverse dependence of the asphaltene/resin ratio upon the vanadium content in resins. This indicates the diminishment of asphaltene precipitation ability with an increase in the content of vanadyl complexes in heavy oil resins. Experiments have shown that the addition of vanadyl porphyrins to resins enhances their inhibition activity toward asphaltene precipitation. For this purpose, vanadyl porphyrins have been concentrated by N,N-dimethylformamide extraction from resins and additionally purified by column chromatography. The obtained vanadyl porphyrin concentrate has been added to resins at the ratio of 1–5 wt %, and its influence on asphaltene stabilization has been further evaluated. Evaluation has been performed by measuring the optical density of deasphalted oil obtained by dilution of the crude oil with 20-fold excess of n-hexane, where resins with various contents of vanadyl porphyrins have been initially dissolved. The change in composition and properties of precipitated asphaltenes has been analyzed, and an increase in their absorbance, aromaticity, and degree of ring fusion with the growth of the vanadyl porphyrin content in resins has been demonstrated. Results have shown the efficiency of vanadyl porphyrins in resins as inhibitors of asphaltene precipitation.

Effects of reservoir rock pore geometries and ultrasonic parameters on the removal of asphaltene deposition under ultrasonic waves

“…Then the solutions were homogenized by mixing with a magnetic stirrer for 30 min. Because complex components and resins (found in crude oil) can inhibit asphaltene precipitation in the micromodel [38] , [39] , the synthetic oil is utilized instead of crude oil to precipitate asphaltene.…”

Review of Asphaltenes in an Electric Field

“…Heavy oils have a considerable amount of asphaltene-resinous components, heteroatoms (S, N, and O), and metals (vanadium and nickel) . The asphaltenes in heavy oils contain iron, vanadium, and nickel (up to 1%), of which the proportion of vanadium is more than 80%. , Vanadylporphyrins, one of the most common forms of crude oil metalloporphyrins, play an important role in asphaltene aggregation, fouling, and deposition. − …”

Insights into the Self-Aggregation of Porphyrins and Their Influence on Asphaltene Aggregation

“…In addition, there is no clear understanding of the role of porphyrins on asphaltene aggregation during the formation of asphaltene supramolecular aggregates. Thus, exploring the roles of porphyrins on the aggregation of asphaltenes is significant for researching the aggregation of asphaltenes and solving the problems caused by asphaltenes. − …”

“…Different from the complexity of the asphaltene structure, porphyrins or metalloporphyrins have a specific molecular structure, including the aromatic group, pyrrolic ring, a metal ion, and a series of pendants. Until now, three typical metalloporphyrins have been identified from petroleum, including etioporphyrins, deoxophylloerythroetioporphyrins, and rhodoetioporphyrins. − Petroleum porphyrins not only have the characteristics of high conjugation and aromaticity but also have a rigid plane, which is prone to form supramolecular aggregates with petroleum molecules through various forces such as π–π stacking and hydrophobic interaction. − Thus, the aggregation between porphyrins and asphaltene is generally considered to be an important integral part of the asphaltene aggregation. Zheng et al employed trapped ion mobility spectrometry-time-of-flight mass spectrometry and Fourier-transform ion cyclotron resonance mass spectrometry to enrich and characterize the vanadyl porphyrins in heavy crude oil and found that porphyrins have strong molecular aggregation potential with themselves and other petroleum molecules .…”