Effect of naphthenate formation on the anti-adhesive behavior of clathrate hydrates at a water-oil interface

Abstract

This work investigates the effect of naphthenic acid and naphthenate on the adhesion behavior of a clathrate hydrate probe at a water-oil interface. The addition of 0.5 wt % myristic acid in the cyclopentane (CP)/n-decane mixture reduces the adhesion force acting on the probe by 51.8% from the lowered interfacial tension between the hydrate probe and aqueous phase. With the basic aqueous solution, the precipitate layer of calcium naphthenate is formed at the water-oil interface. When the concentration of myristic acid rises above 0.1 wt %, the precipitate layer formed at the interface blocks the contact between the hydrate probe and aqueous phase completely. The anti-adhesive force pushing on the hydrate probe is induced toward the positive vertical direction. In this case, the precipitated calcium naphthenate acts like an anti-agglomerant (AA) that inhibits the agglomeration of hydrate particles. Our present findings imply that the crude oil of high acidity may alleviate the agglomeration of hydrate particles in the oil pipeline by inducing naphthenate formation.