Surfactant effects on gas hydrate formation

Abstract Micellar solutions were found to increase gas hydrate formation rate and alter formation mechanism for ethane and natural gas hydrates. A critical micellar concentration (CMC) of sodium dodecyl sulfate water solution was found to be 242 ppm at hydrate-forming conditions, where CMC was best determined by hydrate induction time. At surfactant concentrations above the CMC, hydrate formation rates in a quiescent system increased by a factor greater than 700. Above the CMC, hydrates initiated subsurface around the micelle-solubilized hydrocarbon gas. Developing hydrate particles migrated and adsorbed on the water-wet cell walls at the water–gas interface, where interstitial water–surfactant solution of the packed hydrate particles continued to react at the high rate. The development overcomes major limitations of future hydrate use in an industrial-scale natural gas storage process.