Interfacial measurements for laboratory evaluation of kinetic hydrate inhibitors

Abstract

The work presented here set out to seek a possible correlation between the interfacial properties of kinetic hydrate inhibitors (KHIs) and their performance (evaluated in batch reactors). To achieve that purpose, the surface activity of different KHIs and their effects on the rheological properties of the water/gas interface were studied in- and outside the hydrate stability zone (HSZ) using a high-pressure pendant drop tensiometer. Though all the tested KHIs showed substantial interfacial properties, neither their surface activity nor the interfacial dilatational elasticity of the KHI layer adsorbed at the water/gas interface measured outside the HSZ correlates with their performance as hydrate inhibitors. For the experiments conducted inside the HSZ, the variation rate of the dilatational elastic modulus of the water/gas interface measured in the initial moments of hydrate film growth appeared to be directly related to the KHIs' performance. This experimental observation offers a new way of evaluating KHIs in the laboratory.