Effect of SDS/THF on thermodynamic and kinetic properties of formation of hydrate from a mixture of gases (CH4+C2H6+C3H8) for storing gas as hydrate

Abstract

In this work, the effect of sodium dodecyl sulfate (SDS) and combined effect of sodium dodecyl sulfate (SDS) and tetrahydrofuran (THF) on thermodynamic and kinetic properties of CH4+C2H6+C3H8 hydrate formation have been studied. Four different concentrations of sodium dodecyl sulfate (100ppm, 500ppm, 1000ppm and 1500ppm) have been used to see its effect on phase equilibrium condition and formation kinetics. Though sodium dodecyl sulfate (SDS) does not vary the pressure–temperature condition of hydrate formation, it has a prominent favorable effect on induction time, gas consumption, storage capacity and formation rate. The addition of 3% (mol) tetrahydrofuran (THF) to water+SDS system results in large shifts in phase equilibrium boundary to lower pressure and higher temperature. It has been noticed that the addition of tetrahydrofuran further enhances the formation rate. So the mixture of sodium dodecyl sulfate (SDS) and tetrahydrofuran (THF) can be effectively used as promoter for storing natural gas as hydrate.