Deterring Effect of Resins on the Aggregation of Asphaltenes in n-Heptane

Abstract

Asphaltene precipitation can cause clogged pipelines, of which the alleviation costs the oil industry billions of dollars per year. Asphaltenes are a diverse set of macromolecules native to crude oil and are classified by their lack of solubility in light alkanes. Resins are another native component of crude oil that have been implicated in both deterring and promoting asphaltene aggregation. Here, we design a systematic set of model asphaltenes and resins to investigate the molecular features that affect the initial stages of asphaltene precipitation. We use extensive all-atom molecular dynamics simulations to quantify aggregation behavior based on the isodesmic aggregation free energy of each system. These free energies are then fit to a linear model based on asphaltene and resin molecular features. We find that all model resins tested for this study either deter or do not affect asphaltene aggregation in a light crude oil environment. The inclusion of heteroatoms (0.22 kcal mol −1 atom −1 ) and aromatic carbon atoms (0.06 kcal mol −1 atom −1 ) in resins have the largest deterring effect on asphaltene precipitation. These findings and models represent a possible framework for using select resins to prevent 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

“…61 Because of their interactions with asphaltenes, resins can deter the asphaltenes aggregation process. 48 Resins can function as a bridging material that connects the polar asphaltenes to the nonpolar saturates in crude oils through various mechanisms, e.g., micelle-type formation, 37 peptization of the asphaltene core, 62 or supramolecular growth. 50 It is believed that due to the opposite surface charges of resins and asphaltenes fractions, the resins− asphaltenes molecular interactions are preferred over asphaltene−asphaltene interactions.…”

“…Polar and aromatic functional groups present within the internal molecular structure of asphaltene, including carboxylic acids, carbonyls, phenols, pyrrolic, and pyridinic nitrogen, have the capability of forming hydrogen bonds. These groups can donate or accept protons inter- and intramolecularly. , It has been found that sulfur and oxygen heteroatoms strongly contribute to the aggregation of asphaltenes particularly in n -heptane solution, and the oxygen-containing compounds possibly drive asphaltene aggregation through hydrogen bonding . The most likely mechanisms of asphaltene aggregation involve π–π interactions between aromatic sheets (electrostatic and/or van der Waals forces), hydrogen bonding between functional groups (significant in the presence of water), coordination interactions, and acid–base interactions (Figure ).…”

“…Structurally, resins are akin to asphaltenes, but they have a higher H/C ratio (1.2–1.7), lower aromaticity, and lower molecular weight compared to asphaltenes. ,, Relatively longer aliphatic side chains and smaller chromophores contribute to higher solubility of resins in aliphatic solvents . Because of their interactions with asphaltenes, resins can deter the asphaltenes aggregation process . Resins can function as a bridging material that connects the polar asphaltenes to the nonpolar saturates in crude oils through various mechanisms, e.g., micelle-type formation, peptization of the asphaltene core, or supramolecular growth .…”

Model Carboxyl-Containing Asphaltenes as Potential Acceptor Materials for Bulk Heterojunction Solar Cells

“…Among all the candidates, of high interest as alternative acceptors are graphene-like small molecules capable of forming stacked structures due to π–π interactions, which enables efficient charge transfer . Asphaltenes are natural graphene-like particles, products of deep oil refining, which cost orders of magnitude less than similar synthesized carbon nanoparticles. − Moreover, for the oil refining industry, the issue of asphaltene recycling and disposal is in great demand, since asphaltenes represent an abandoned byproduct. , Several studies have already demonstrated the electronic conductivity of asphaltenes, and suggested their use in various electronic applications, − including the design of organic solar cells. − In particular, the Chianelli group has made several attempts to create an asphaltene-based dye-sensitized solar cell, although the maximum PCE obtained did not exceed 2.0%. , Higher PCEs can be achieved through a variety of changes, from nanoscale molecular structure modifications to optimization of the device design.…”