Reduction Clathrate Hydrates Growth Rates and Adhesion Forces on Surfaces of Inorganic or Polymer Coatings

Hydrate plugging is one of the major risks for oil and gas transportation in pipelines. To mitigate the adhesion between hydrate particles and pipeline walls, hexagonal boron nitride (HBN), polydimethylsiloxane (PDMS), and fluoro-coating (F-coating) were added with hydrophobic fuming SiO2 as coating materials, which were coated on four different substrates (X70 steel, X80 steel, zirconia plate (ZrO2), and tinplate). The adhesion force between tetrahydrofuran (THF) hydrate particles and coated substrates was measured by a micromechanical force apparatus (MMF). For the X70 substrate with F-coating, the adhesion force was reduced by 80.3% when the mass fraction of SiO2 was increased from 1 wt % (0.0152 N/m) to 4 wt % (0.0030 N/m). SiO2 exhibits hydrate-phobic properties. The adhesion forces were 0.0105, 0.0027, and 0.0043 N/m for X80 (bare), X80+HBN, and X80+PDMS. PDMS+SiO2(1–4 wt %) coating was found able to slow the growth rate of hydrate. In a high-pressure reactor, methane hydrate growth on PDMS+SiO2(4 wt %) coating on the tinplate substrate was studied. No growth of methane hydrate on the coated layer was observed, while there was full coverage on the noncoated layer. The presence of coating was found effective for hindering the growth and attachment of both THF and methane hydrates. Surface morphology was believed to be one of the main factors affecting the adhesion and growth characteristics of hydrate particles. Hydrate-phobic coating has been put forward in this work that refers to a functional coating that prevents hydrates.