Asphaltene dispersants weaken the synergistic modification effect of ethylene-vinyl acetate and asphaltene for model waxy oil

Mechanistic Study on the Effect of Molecular Structure Characteristics of Asphaltene on the Synergistic Modification with EVA on Model Waxy Oil

“…Below this concentration, augmenting asphaltene concentration heightens the WAT, but surpassing this threshold rapidly diminishes asphaltene’s influence on the WAT. Recent research from our group corroborates these findings, , affirming that asphaltenes do, indeed, heighten the WAT, with this effect subject to influences such as solvent composition and active agents.…”

“…Below this concentration, augmenting asphaltene concentration heightens the WAT, but surpassing this threshold rapidly diminishes asphaltene's influence on the WAT. Recent research from our group corroborates these findings, 24,26 affirming that asphaltenes do, indeed, heighten the WAT, with this effect subject to influences such as solvent composition and active agents. Furthermore, beyond their innate capability to enhance the flow properties of waxy oils, recent studies have proposed that asphaltenes can augment the modification potential of polymer PPDs, denoted as the "synergistic modification effect.″ In experiments conducted with Jianghan crude oil, Liu et al 27 compared the effects of a range of self-developed pour point depressants and observed that those with specific functional groups form novel aggregates with asphaltenes present in the crude oil, substantially enhancing the modification effect.…”

“…As the most polar substances in the oil phase, asphaltenes tend to self-aggregate, leading to an increase in particle size and the formation of solid precipitates. ,− Factors affecting the self-aggregation tendency of asphaltenes include solvent composition, active substances in the oil phase, and the molecular structure of the asphaltenes themselves. ,, As a surfactant, EVA’s molecular structure contains both polar and nonpolar portions, allowing it to adsorb onto asphaltene particles and reduce asphaltene particle size, thereby enhancing asphaltene dispersion stability. Therefore, we tested the particle size of the oil samples containing asphaltene before and after the addition of EVA, and indirectly reflected the adsorption of EVA on the surface of asphaltene through the change of the particle size.…”

“…In contrast, scholars such as D’Avila et al concluded that there is a synergistic modification effect between asphaltenes and EVA PPDs with the function of reducing the WAT. Nevertheless, a substantial body of research posits that asphaltenes can elevate the WAT. ,− Kriz hypothesized that the ability of asphaltenes to raise the WAT depends on asphaltene concentration, suggesting the existence of a “critical concentration” of asphaltenes in the oil phase. Below this concentration, augmenting asphaltene concentration heightens the WAT, but surpassing this threshold rapidly diminishes asphaltene’s influence on the WAT.…”

Performance improvement on the cold flow properties of crude oil with high asphaltene by adjusting the polarity of the third monomer in polymers

“…It was suggested that aromatic ring could produce conjugation with asphaltenes and had stronger dispersion performance to asphaltenes. EVA PPD adsorbs on the asphaltene surface and forms composite PPD while improving the dispersion stability of asphaltene 41 . Thus the presence of benzene ring in NPA enhanced the solubility and dispersibility of asphaltenes macromolecules.…”