Inhibition on methane hydrate formation by polyacrylate superabsorbent hydrogel

Abstract

Hydrate blockage in submarine oil and gas transport pipelines has always been the focus of attention in the oil and gas industry. Using superabsorbent hydrogels (SAHs), three-dimensional network structures with numerous hydrophilic groups, to prevent hydrate formation in gas/oil pipeline has been endowed with theoretical potential. In this work, the inhibition of traditional polyacrylate SAHs on methane hydrate formation was systematically studied via both numerical and morphological analysis. In methane hydrate formation from SDS solution (1 mmol/L), SAHs at relatively low swelling ratio of 10 and 5 produced obvious inhibition on hydrate nucleation, prolonging the induction time from 27.6 ± 14.5 min to 155.5 ± 157.1 and 334.2 ± 126.6 min, respectively. And the water fixation effects of SAHs could prevent methane hydrate growth from efficiently, with the inhibition efficiency reaching 65.83 ± 1.82 %, 81.82 ± 1.83 %, and 87.96 ± 1.66 % at swelling ratio of 20, 10, and 5, respectively. When used in simulated DI water/decane (W/O) mixture, at water content of 30 %, SAHs performed well at swelling ratio of 50 (mass ratio of 0.6 %), preventing methane hydrate formation by 94 % and keeping the mixture with low viscosity and good fluidity; at water content of 70 %, SAHs produced excellent performance at swelling ratio of 50–100 (mass ratio of 1.4%–0.7 %), preventing methane hydrate formation by 80 % and avoiding increasing the viscosity of the mixture. The results in this work confirmed the promising application potential of SAHs in gas/oil pipeline flow assurance.