Effect of an anionic surfactant on different type of hydrate structures

Modelling of hydrate formation kinetics: State-of-the-art and future directions

“…A slight increase in the operating temperature of jacketed reactors during hydrate growth has already been reported by some investigators (Giavarini et al, 2003;Zhong and Rogers, 2000;Karaaslan et al, 2002;Tsuji et al, 2004;Lee et al, 2005aLee et al, , 2007Linga et al, 2007). Zhang et al (2004), in particular, demonstrated the existence of a clear correlation between the temporal evolution of the gas consumption rate and the operating temperature in the reactor for their data.…”

“…The non-ionic surfactant (nonylphenol ethoxalate), on the other hand, acted as a hydrate inhibitor for all operating conditions analysed. The same anionic surfactant was utilised by Karaaslan et al (2002) for the formation of sI (methane) and sII (propane-rich gas mixture) hydrates. It acted as a hydrate promoter in both systems, but the effect was much more pronounced in the case of the structure I compound.…”

Static Formation and Dissociation of Methane+Methylcyclohexane Hydrate for Gas Hydrate Production and Regasification

“…Although no extra devices and energy for disturbance are needed for quiescent reactors, other nonmechanical promoting methods should be studied. Some surfactants, such as sodium dodecyl sulfate (SDS), could effectively reduce the induction time, raise the gas content, and increase the rate of sI and sII gas hydrate formation [16][17][18][19]. The effects of adding both the surfactants and LMGS on the formation of CH 4 hydrate and CO 2 hydrate in a quiescent reactor have been reported by Sun et al [20] and Zhang et al [21], respectively.…”

Equilibrium hydrate formation conditions for hydrotrope–water–natural gas systems

“…The thermodynamic influence of surfactants such as sodium lauryle sulfate on hydrate formation systems were suggested to be minimal, whereby hydrate formation equilibrium conditions remained the same as in a gas-water system [18,20,23,24]. However, the hydrotrope pTSA, when present in very small quantities in a water-natural gas-hydrate system, influenced the equilibrium hydrate formation conditions when subjected to an isochoric 'temperature cycling' experiment.…”

“…An isochoric 'temperature cycling' experiment is a process of forming hydrates by decreasing the temperature in a gas-water system, while monitoring the pressure-temperature variation, and after formation dissociating the hydrates by increasing the temperature [15]. The experiments in Karaaslan et al [23] indicate a similar characteristic of the anionic surfactant, linear alkyl benzene sulfonic acid (LABSA); however, the authors did not recognise the influence on hydrate dissociation thermodynamics as they had concentrated on the influence of different hydrate structures on the hydrate formation rate. Further, the exact formula of the LABSA was not reported in their publication, thus making it impossible for a definite comparison with pTSA.…”