Alanine rich amphiphilic peptides as green substitutes for hydrate inhibitors: A molecular simulation study

Adding kinetic inhibitors (KHIs) is a common method to prevent hydrate from blocking oil and gas pipe-lines. Considering the pollution of traditional KHIs, several amphiphilic peptides are designed as green KHIs substitutes, and their inhibitory effect and mechanism are studied by molecular simulation. The van der Waals (vdW) interaction between hydrophobic groups and water molecules is the main factor causing different inhibition effects. Hydrophobic groups can enter water cages as guest molecules to immobilize peptides on the hydrate surface. After adding peptides consisting of alanine and lysine (5AK), the growth rate of hydrate slows down by 58.2 % because 5AK has more hydrophobic binding sites. And the addition of threonine can also effectively improve the inhibitory effect of peptide. Before 110 ns, the inhibitory effect of peptides consisting of alanine and threonine (5AT) is even stronger than that of 5AK. The results explain the mechanism of peptide inhibiting hydrate growth, and provide theoretical guidance for the development of new KHIs.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Adding amphiphilic peptides as green KHIs substitutes can effectively inhibit hydrate growth by utilizing the vdW interaction between hydrophobic groups and water molecules. Peptides consisting of alanine and lysine (5AK) and alanine and threonine (5AT) have been studied, and it is found that 5AK with more hydrophobic binding sites exhibits a higher inhibitory effect. Additionally, the addition of threonine further improves the inhibitory effect of the peptide. These findings provide theoretical guidance for the development of new KHIs.