Work

Phase Equilibria and Stability of an HS-I Hydrate and a Related Phase Formed with Tri- n -butyl, n -Hexylammonium Salts under Methane, Carbon Dioxide, and Nitrogen Gas Pressures

Year: 2025

Type: article

Abstract: Phase equilibrium data of clathrate hydrates are essential for evaluating their potential in gas storage and separation. In this study, we determined three-phase (hydrate–gas–liquid) equilibrium points for the systems (N4446Cl or N4446Br) + H 2 O + (CH 4, CO 2, or N 2 ) at pressures of up to 10 MPa. N4446Cl, previously reported to stabilize the hexagonal structure-I (HS-I) phase, formed hydrates with all three gases even at aqueous compositions lower than those reported earlier. The P – T slope analyses suggest gas uptake potentials for CH 4 and CO 2 comparable with N4446Cl hydrates and N4446Br hydrates. The slope analysis suggests that N4446Br likely forms a phase similar to the HS-I structure under CH 4 and CO 2 but shows reduced capacity for N 2 . These results expand the known guest species capable of stabilizing HS-I hydrates and highlight the distinct gas-specific behavior of bromide and chloride salts. The phase equilibrium data reported here provide a basis for designing HS-I hydrate-based gas storage and separation applications, including the capture of CO 2 from lean mixtures.

Source: Journal of Chemical & Engineering Data

DOI: 10.1021/acs.jced.5c00568

Authors: Sanehiro Muromachi, Satoshi Takeya, Kiyofumi Suzuki, Norio Tenma

Institutions: Yokohama National University, National Institute of Advanced Industrial Science and Technology

Language: English

Topic: Methane Hydrates and Related Phenomena

Subfield: Environmental Chemistry

Field: Environmental Science

Domain: Physical Sciences

SDG: Climate action

Open Access status: green

Funder: Japan Society for the Promotion of Science