Oleic acid potassium soap: A new potential kinetic promoter for methane hydrate formation

Abstract Low gas hydrate formation rate is one important reason that limits the application of hydrate-based technologies, while development of new kinetic promoter is an alternative method to solve this problem. In this work, oleic acid potassium soap (OPS) was proposed to use as a new potential kinetic promoter to improve methane hydrate formation process. t 80 was greater than 360 min when methane hydrate formed in redistilled water, while t 80 can decrease to within 100 min with the addition of OPS. Compared OPS with published kinetic promoter of sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), the promoting effect of OPS was better than SDBS, and had similar promoted effect with SDS. In addition, both thermodynamic and kinetic results showed that addition of OPS had little effect of methane hydrates equilibrium conditions. Promoting effect mechanism of OPS was that the double bond and hydrophobic groups enhanced the solubility of methane, which finally improved methane hydrate formation.