Medium dependence of asphaltene agglomeration inhibitor efficiency

TL;DR

This study investigates how the efficiency of asphaltene agglomeration inhibitors varies with medium dependence, revealing that self-assembly of inhibitors can reduce their effectiveness in different solvents.

Contribution

It combines vapor pressure osmometry experiments with Monte Carlo modeling to elucidate the medium-dependent behavior of inhibitor efficacy on asphaltene agglomeration.

Findings

Inhibitor efficiency declines due to self-assembly phenomena.

Medium polarity influences inhibitor adsorption and effectiveness.

Monte Carlo simulations explain unexpected molar mass trends.

Abstract

Applying chemical additives (molecule inhibitors or dispersants) is one of the common ways to control asphaltene agglomeration and precipitation. However, it is not clear why at some conditions the synthetic flocculation inhibitors as well as resins not only do not inhibit the asphaltene agglomeration,, they may also promote it, and why the increasing of the additive concentration may lead to the diminishing of their efficacy. To clarify this issue, in the present work we have performed a set of vapor preassure osmometry experiments investigating the asphaltene agglomeration inhibition by commercial and new inhibitor molecules in toluene and o-diclorobenzene. Monte Carlo computer modeling has been applied to interpret some unexpected trends of molar mass of the Puerto Ceiba asphaltene clusters at different concentrations of inhibitor, assuming that inhibitors efficiency is directly related to their adsorption on the surface of asphaltene or its complexes. It has been found that a self-assembly of inhibitor molecules, induced by relative lyophilic or lyophobic interactions, may be a reason of the inhibitor efficacy declining.