Phase Equilibrium of Hydrogen Clathrate Hydrates with Propylene Oxide and 1,2-Epoxycyclopentane

Abstract

This study examined the phase behavior of hydrogen hydrates with additives containing oxygen-containing groups. The phase equilibrium of the H2 + propylene oxide (PO) + water hydrate system and the H2 + 1,2-Epoxycyclopentane (ECP) + water hydrate system was measured using the isochoric pressure search method. The mole fractions of PO and ECP were 0.056 and 0.028, respectively. The experimental data were determined in the temperature range of 273.90 to 285.20 K and the pressure range of 3.18 to 18.57 MPa. In the presence of PO and ECP, the hydrate phase equilibrium of the systems moved to a lower pressure and a higher temperature region compared to that of the hydrogen hydrates without additives. The addition of ECP with a mole fraction of 0.056 had the best promotion effect among all reported sII-type thermodynamic additives. The data obtained in this study also showed that the equilibrium was affected by the ether (c–o–c) functional group in epoxy heterocycle compounds, which was the effective functional group in changing the equilibrium conditions of hydrogen hydrates. The results provided a basis for hydrogen storage and transportation based on hydrate technology.

Energy Storage in Hydrates: Status, Recent Trends, and Future Prospects

“…Chen et al studied hydrogen hydrate phase equilibrium with epoxy cyclopentane (ECP) and propylene oxide promoters; a stoichiometric concentration (5.6 mol %) of epoxy cyclopentane was found to be the most effective sII thermodynamic promoter with an increase (shift) in temperatures of 2–4 K higher than those of tetrahydrofuran and cyclopentane. Further, they investigated the kinetics of ECP (5.56 mol %) mixed hydrogen hydrate by employing ECP solution, ECP solution with kinetic promoter SDS, ECP solution with stainless steel fibers, and preformed ECP hydrate particles at 273.2 K and 12.2 MPa .…”

Perspectives on facilitating natural gas and hydrogen storage in clathrate hydrates under a static system

“…194,195 (d) Phase equilibrium boundaries of binary H 2 + various sII promoters. [198][199][200][201] (e) Phase equilibrium boundaries of binary H 2 + various sH promoters. 202,203 (f ) Phase equilibrium boundary of binary TBAF (3.3 mol%) + CH 4 211 hydrates and that of TBAF (3.4 mol%) + H 2 210 hydrates in comparison with pure CH 4 hydrate.…”

“…Veluswamy and colleagues reported rapid storage of methane 196 or hydrogen 197 in hydrates formed from THF solutions. Numerous studies have examined the thermodynamics of hydrogen hydrate promoters, including THF, 197 cyclopen-tane (CP), 198 tetrahydrothiophene, 199 furan, 199 1,3-dioxolane, 200 2,5-dihydrofuran, 200 1,2-epoxycyclopentane (ECP), 201 and propylene oxide. 201 The phase equilibrium boundaries of these promoters are summarized in Fig.…”

Geometric and Hydrophilic Effects of Oxirane Compounds with a Four-Carbon Backbone on Clathrate Hydrate Formation

“…In particular, 12ECP significantly increased the dissociation temperature of CH 4 hydrate by ∼23 K at any given pressure, demonstrating a superior promotion capacity compared to tetrahydrofuran or cyclopentane . Potential applications of 12ECP hydrates for energy gas storage − and CO 2 capture were also suggested.…”