Hydrate formation in pipelines and gas transmission lines is a significant concern for the oil and gas industry, leading to increased costs for repairs and maintenance. Kinetic hydrate inhibitors (KHIs) are water-soluble polymers used in low concentrations (less than 1 wt%) to prevent hydrate formation. This study investigates the potential of tri-block copolymers as KHIs. Three different tri-block copolymers, PS-b-PEG-b-PS, PDMAEMA-b-PEG-b-PDMAEMA and PVCap-b-PEG-PVCap were synthesized using the atom transfer radical polymerization (ATRP). The copolymers were characterized by 1H NMR and FTIR spectroscopy. Their kinetic inhibition performance was evaluated and compared to three commercial inhibitors (PVP, Luvicap EG, and PVCap) at concentrations of 0.05 wt% and 0.1 wt%. Results from methane gas hydrate inhibition tests revealed that the PVCap-b-PEG-b-PVCap block copolymer exhibited superior kinetic inhibition performance. At a concentration of 0.1 wt% this copolymer increased the induction time of hydrate formation by approximately 7-fold compared to pure water, extending from 165 s to 1180 s. Additionally, the average gas consumption rate, an indicator of hydrate particle growth, decreased by approximately 8-fold when at 0.1 wt% concentration compared to pure water. In addition, the cloud point temperature of the synthesized copolymers was measured. The results showed that the PVCap-b-PEG-b-PVCap copolymer had a clouding temperature of approximately 67 °C. This significant improvement overcomes the low cloud point temperature limitation of conventional PVCap inhibitors. Overall, the findings show that the PVCap-b-PEG-b-PVCap block copolymer can be introduced as a new high cloud point KHI in methane-water systems.

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