Synergistic effect of sulfonated castor oil and porous medium on kinetics of gas hydrates formation

Abstract

In recent years, interest in gas hydrates has increased as they represent a potential energy source and an alternative to the current environmentally friendly method of storing and transporting natural gas. In this study, the synergistic effect of a new promoting reagent – sulfonated castor oil (SCO) – and a porous medium on the formation and decomposition of methane and methane-propane hydrates was compared to that of sodium dodecyl sulfate (SDS) using the high-pressure differential scanning calorimetry (HP-μDSC) method. DSC tests demonstrated that water conversion in the presence of SCO in a porous substrate for methane hydrates reached 95% at high water saturation, which can be attributed to improved mass transfer in the presence of surfactants. However, this value did not exceed 60% for the hydrate of methane–propane mixture, indicating that the mechanism of promotion of the sI and sII hydrates differs. According to kinetic calculations based on the Avrami equation, both SDS and SCO accelerate the formation of hydrates, but for SCO, this is possible with less supercooling. The calorimetric measurements and kinetic parameter calculations demonstrated that SCO is comparable to the well-known reagent SDS in promoting activity in porous media with varying water saturation.