Facile one-step functionalised graphene oxide-phytic acid coating towards effective wax inhibition in waxy oil transportation

Abstract

Wax deposition in pipelines is a global issue during the production and transportation of oil. Recently, superhydrophilic/underwater superoleophobic coatings have garnered much attention due to their wax inhibition potential based on water film theory. Herein, carbon steel (CS) substrates were made superhydrophilic by coating phytic acid (PA) functionalised graphene oxide (GO) materials prepared by very simple process. The superhydrophilic GO-PA coatings induced the formation of a hydration layer on the surface, thus inherently showing underwater superoleophobic properties in a water-contained waxy oil system. The optimised GO-PA/CS surface possessed a water contact angle of nearly 0° and an underwater oil contact angle of ∼ 160°. This coating demonstrated up to 89.5 % enhancement in oil passing speed during the oil transportation test. This enhancement is particularly significant for reducing wax deposition in laminar and transitional flow regimes. Moreover, in the cold-finger wax deposition tests, a wax inhibition efficiency of 95.8 % was achieved with the optimised GO-PA/CS surface in the laminar flow regime. Therefore, this research provides insights into a mechanically and chemically stable GO-based coating achieved via a facile one-step functionalisation, which has not been previously reported in the literature for applications in waxy oil transportation.