Role of Structural Rigidity and Collective Behaviour in the Molecular Design of Gas Hydrates Anti-Agglomerants

TL;DR

This study uses molecular dynamics simulations to explore how molecular structure, rigidity, and collective behavior of antiagglomerants influence their effectiveness in preventing hydrate particle agglomeration in oil pipelines.

Contribution

It introduces a detailed molecular-level analysis of how structural modifications in antiagglomerants affect their performance, highlighting the role of aromatic groups and collective effects.

Findings

Aromatic group location impacts AA performance.

Molecular rigidity influences hydrate prevention.

Methodology applicable to other particle control industries.

Abstract

Antiagglomerants (AAs) are surface active molecules widely used in the rubber and petroleum industry, among others. In the petroleum industry, it is believed that AAs strongly adsorb to the surface of hydrate particles to prevent the growth of clathrate hydrate within oil pipelines. Small changes in their molecular structures can strongly affect the thermodynamic and kinetic stability of the system as a whole. Here we employ molecular dynamics simulations to study the interplay between the modification of the molecular structure, rigidity and collective effects of AAs designed to prevent hydrate agglomeration in the conditions encountered in rocking cell experiments. The AAs are surface-active compounds with a complex hydrophilic head and three hydrophobic tails whose structural rigidity is enhanced with the attachement of a simple aromatic group. We observe that the aromatic group can positively or negatively affect the performance of the AAs, depending on its location along the hydrophobic tail. Our approach is based on first quantifying the molecular mechanisms responsible for the macroscopic performance. Although the mechanisms at play depend on the application, the methodology implemented could be applicable to other high-tech industries, where the agglomeration of small particles must be controlled.