Comparison of Kinetic Hydrate Inhibitor Performance on Structure I and Structure II Hydrate-Forming Gases for a Range of Polymer Classes

Abstract

A series of water-soluble polymers has been investigated for comparison of their potential as kinetic hydrate inhibitors (KHIs) for both structure I (SI)- and structure II (SII)-forming gas mixtures. A slow constant cooling test method and steel rocking cells have been used for these experiments. The average hydrate onset temperatures (To) have been used to rank the polymers according to their KHI ability, with the lower To values giving a higher rank. The object of the study was a comparison of the KHI performance for SI versus SII inhibition for a range of polymers and not a study to find the optimal polymer for each hydrate structure. The most interesting comparative results were the large deviations of the ethyl derivative of poly(N-alkylglycine) for the two hydrate systems, where this polymer performed very well with the SI-forming gas but had significantly less effect on the SII-forming gas. Also, poly(2-ethyl-2-oxazoline) (PEtOx) and poly(isopropenyloxazoline)-01 (PiPOx-01) ranked better with SI hy...