Experimental and computational insights into the inhibition of CO2 hydrate formation using biodegradable oligopeptides and their significance in CO2 transport and storage

Abstract

The current emphasis on achieving carbon neutrality underscores the significance of carbon capture, utilization, and storage, making the avoidance of CO2 hydrate formation in transmission and transport pipelines crucial. Considering this, the present study explored the potential of oligopeptides as biodegradable kinetic hydrate inhibitors (KHIs) for inhibiting CO2 hydrate formation. Dipeptides (L-alanyl-L-alanine [Ala-Ala], L-alanylglycine [Ala-Gly], and glycylglycine [Gly-Gly]) and a tripeptide (glycylglycylglycine [Gly-Gly-Gly]) were investigated through a combination of experimental measurements and molecular dynamics (MD) simulations. Onset temperature measurements were obtained to evaluate the inhibition effects of the oligopeptides. The results demonstrated the effective hindrance of CO2 hydrate formation by the oligopeptides at a significantly low concentration (1.0 wt%). The MD simulations provided molecular-level insights into the hydrate inhibition mechanisms of the oligopeptides during CO2 hydrate formation, revealing their influence on the growth, dissociation, and structural dynamics of CO2 hydrates. Additional investigations involving mean square displacement, diffusion coefficients, and radial distribution function provided a deeper understanding of molecular motion, mobility, and hydrate bond disruption in the presence of the oligopeptides. The research findings highlight the efficacy of oligopeptides as novel KHIs for inhibiting CO2 hydrate formation, thereby contributing