Preparation of superhydrophilic coatings for inhibiting hydrate nucleation and repelling crude oil

Abstract

Oil and gas transportation has been plagued by pipeline blockage caused by natural gas hydrates nucleation and crude oil adhesion. While traditional coatings with inhibitory functional groups can inhibit hydrate nucleation, but their inhibitory performance can be restricted by crude oil adhesion. Meanwhile, anti-crude-oil-coatings fail to inhibit hydrate nucleation owing to lack of inhibitory functional groups. Thus, how to coordinate the inhibition and anti-adhesion properties of coatings is a rigorou8s challenge. Moreover, for water-phase dominated pipelines, inhibitory performance of coatings will be inevitably weakened if the coatings cannot offer sufficient density of inhibitory functional groups. Here, we report a strategy for designing coatings with anti-hydrate-nucleation and anti-crude-oil-adhesion properties, which can be achieved by introducing hydrophilic inhibitory functional groups into the polymer polyethylene glycol and constructing micro-nanostructures by coating them with hydrophilic nano SiO₂ onto skeletons of porous Ni foam. Compared with uncoated Ni foam, the hydrate formation induction time of coated Ni foam was prolonged by 517.8 % and the adhesion force with crude oil was reduced by 93.3 %. The micro-nanostructures constructed by nano-SiO₂ and Ni foam increases the density of hydrophilic inhibitory functional groups and minimize the contact area with crude oil, which contribute to improve the anti-hydrate-nucleation and anti-crude-oil-adhesion performances of coatings. Molecular simulation and experimental results indicate that the hydrophilic inhibitory functional groups not only inhibit hydrate nucleation by disrupting the ordering of water molecules, but also repel crude oil by forming hydrated films. Therefore, this study offers an effective strategy for the development of coatings aimed at mitigating pipeline blockages caused by hydrates nucleation and crude oil adhesion.