The Phase Equilibria of Natural Gas Hydrate in the Presence of 1,3-Dimethylcyclohexane and Octyl-β-D-glucopyranoside

• Published in: Molecules
• Main Authors: Qiang Fu, Mingqiang Chen, Weixin Pang, Zengqi Liu, Zhen Xu, Xin Lei
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2024
• Subjects: gas hydrate; phase equilibrium; methane; surfactant; thermodynamics; Organic chemistry; QD241-441; Methane hydrate
• Online Access: https://doi.org/10.3390/molecules29153604; https://doaj.org/article/4003e1b04f7e4f5c87fb3c0f287f31e1

The thermodynamic effect of octyl-β-D-glucopyranoside (OGP) on the formation of methane-1,3-dimethylcyclohexane (DMCH) hydrate was studied in this work. The thermodynamic equilibrium hydrate formation pressures between 275.15 K and 283.15 K were measured by the isothermal pressure search method. Different OGP aqueous solutions (0, 0.1, and 1 wt%) were used in this work. The experimental results show that OGP had no obvious thermodynamic inhibition on methane-DMCH hydrate formation when its concentration was low (0.1 wt%), whereas it had an inhibition on methane-DMCH hydrate formation when its concentration was high (1 wt%). The phase equilibrium hydrate formation pressure of the methane-DMCH-OGP system is about 0.1 MPa higher than that of the methane-DMCH system. The dissociation enthalpies of methane hydrate in different solutions remained uniform, which indicates that OGP was not involved in methane-DMCH hydrate formation. This phenomenon is explained from the perspective of the molecular structure of OGP. As a renewable and biological nonionic surfactant, the concentration of OGP in the liquid phase is low, so OGP can be added to the methane-DMCH system without significant thermodynamic inhibition.