Experimental study on effect of different surfactants and their mixture on the methane hydrate formation

The effects of anionic surfactant sodium dodecyl sulfate(SDS), cationic surfactant hexa decyl trimethyl ammonium bromide(HTABr), nonionic surfactant polyoxy ethylene(20) cetyl ether(Brij-58) and mixtures of SDS with HTABr and Brij-58 have been investigated on hydrate formation kinetics and thermodynamics. Study on the kinetic of hydrate formation is focused on induction time, hydrate formation rate and conversion percent of methane to hydrate. Induction time of hydrate formation is reduced for each test compared to the pure water considerably. Minimum amount of induction time is for mixture of SDS (500 ppm) with HTABr (700 ppm). All of the surfactants and their mixtures are hydrate formation promoters and have increased the formation rate of hydrate. SDS in concentration of 500ppm was the best hydrate formation promoter among the tested surfactants. Conversion percent of methane to hydrate is increased in the presence of these surfactants in the end of hydrate formation. Maximum amount of conversion percent is for SDS in 500ppm concentration. The results demonstrate that these surfactants and their mixtures have no significant effect on the equilibrium point of hydrate formation.

کلیدواژه ها:

Methane hydrate ، kinetic ، formation rate ، surfactants ، mixed surfactants ، induction time ، conversion