Magnetically recoverable nanoparticle organic hybrid materials as kinetic hydrate inhibitors

Abstract

Gas hydrates pose significant risks in the oil and gas industry because of their tendency to form blockages in transportation pipelines under low-temperature and high-pressure conditions. Conventional thermodynamic hydrate inhibitors require high dosages, with associated substantial costs and environmental concerns. Kinetic hydrate inhibitors (KHIs), which operate at much lower dosages, offer a more sustainable solution but are often limited by environmental compatibility and recovery problems. In this study, we introduce a novel class of magnetically recoverable KHIs utilizing nanoparticle organic hybrid materials (NOHMs), named NOHM-IPNIPAM, featuring a tunable Fe3O4 core-SiO2 shell structure with poly(N-isopropylacrylamide) (PNIPAM) as the organic component. The chemical properties of NOHM-I-PNIPAM were characterized using TEM, FT-IR, and XPS. The hydrate kinetic inhibition performance was evaluated with a CH4 (90%) + C2H6 (7%) + C3H8 (3%). Various grafting densities of PNIPAM on NOHMs and weight fractions of NOHM-I-PNIPAM were used to explore NOHM-I-PNIPAM's role in the formation kinetics of natural gas hydrates under different cooling rates. Notably, the NOHM-I-PNIPAM (1.0), when utilized at a 2 wt% dosage, exhibited the most effective inhibition performance in terms of the onset temperature of CH4 (90%) + C2H6 (7%) + C3H8 (3%) hydrate. Considering the effective concentration of PNIPAM in NOHM-I-PNIPAM, the inhibition performance was found to be comparable to that of conventional PNIPAM. Results showed that NOHM-I-PNIPAM is a promising KHI due to its combined properties of magnetic separation and comparable kinetic inhibition performance. Experimentally, NOHM-I-PNIPAM demonstrated stability over long-term cycles and was effectively magnetically separated. Hence, we believe that this work can provide valuable insights into the potential of NOHMs as recoverable and reusable KHIs for industrial applications for flow assurance.