| Summary: | Large amounts of inhibitors are consumed annually to tackle the two critical flow assurance problems of pipelines in the oil–gas industry, namely, corrosion and gas hydrate blockages. Such strategies can be optimized when the implications of corrosion inhibitor on gas hydrate formation are clarified as well as the underlying mechanisms. Therefore, molecular dynamics simulations were performed in this study to elucidate the effects of a conventional imidazoline corrosion inhibitor [1-(2-aminoethyl)-11-alkyl-imidazoline, AAI] on the formation of methane hydrate. A significant hydrate kinetics inhibition effect was observed according to the F 4φ analysis at different locations. The ability of AAI to inhibit the hydrate formation was mainly attributed to its constituent of the hydrophobic group, which either displaced the methane molecules and destroyed the stability of water cages (AAI concentration at 4.9%), or separated the methane from the water molecules to markedly reduce their interactions (AAI concentration at 10.3%). In contrast, the contributions by the hydrophilic group of AAI were secondary with respect to the limited contact with water to disrupt the hydrogen bonds of the water cages. The thermodynamic analysis revealed that the methane hydrate particles were hardly deposited on the AAI-covered pipeline surface due to the strong repulsion effect of the hydrophobic groups on the water cages. Such molecular insights provide theoretical guidance for evaluating the functional groups of corrosion inhibitors that may affect the formation of gas hydrates and, subsequently, modifying these functional groups to achieve a dual inhibition influence on both pipeline corrosion and gas hydrate formation.
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