Methane Hydrate Formation and Dissociation in Synperonic PE/F127, CTAB, and SDS Surfactant Solutions

Formation and dissociation conditions for methane hydrates were investigated in the presence of aqueous solutions of a no-ionic triblock copolymer synperonic PE/F127 (PE/F127) at 377, 710, 1530 ppm with the aim of evaluating the promotion activity. A cationic cetyltrimethylammonium bromide (CTAB) and an anionic sodium dodecyl sulfate (SDS) surfactant were also tested and conducted at 356, 705, 1500 ppm and 376, 701, 1510 ppm respectively. Experiments with the three surfactants were carried out in an isochoric autoclave under the same conditions: near the ice normal melting point (273.15 K), as the cooling temperature of the autoclave, and five initial pressures stated from 3.5 to 12.0 MPa. Performance of these surfactants was assessed by reporting hydrate-liquid water-vapor (H-L-V) phase equilibria, enthalpies of dissociation estimated using the Clausius-Clapeyron equation, induction times, crystallization temperatures, growth rates and theoretical methane consumptions. In brief, the obtained induction time for PE/F127 was higher than CTAB but lower than SDS, the growth rate between PE/F127 and SDS were similar at lower concentrations, and the maximum gas consumption for PE/F127 was reached at 1530 ppm but this methane uptake was far from those results using SDS.