title: Thermodynamic stability, spectroscopic identification, and gas storage capacity of CO2-CH4-N2 mixture gas hydrates: implications for landfill gas hydrates.
abstract: Landfill gas (LFG), which is primarily composed of CH(4), CO(2), and N(2), is produced from the anaerobic digestion of organic materials. To investigate the feasibility of the storage and transportation of LFG via the formation of hydrate, we observed the phase equilibrium behavior of CO(2)-CH(4)-N(2) mixture hydrates. When the specific molar ratio of CO(2)/CH(4) was 40/55, the equilibrium dissociation pressures were gradually shifted to higher pressures and lower temperatures as the mole fraction of N(2) increased. X-ray diffraction revealed that the CO(2)-CH(4)-N(2) mixture hydrate prepared from the CO(2)/CH(4)/N(2) (40/55/5) gas mixture formed a structure I clathrate hydrate. A combination of Raman and solid-state (13)C NMR measurements provided detailed information regarding the cage occupancy of gas molecules trapped in the hydrate frameworks. The gas storage capacity of LFG hydrates was estimated from the experimental results for the hydrate formations under two-phase equilibrium conditions. We also confirmed that trace amounts of nonmethane organic compounds do not affect the cage occupancy of gas molecules or the thermodynamic stability of LFG hydrates.
authors.affiliation: Department of Energy and Resources Engineering, Korea Maritime University, Busan, Korea.
authors.forename: Hyeong-Hoon
authors.initials: HH
authors.lastname: Lee
authors.forename: Sook-Hyun
authors.initials: SH
authors.lastname: Ahn
authors.forename: Byong-Uk
authors.initials: BU
authors.lastname: Nam
authors.forename: Byeong-Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Gang-Woo
authors.initials: GW
authors.lastname: Lee
authors.forename: Donghyun
authors.initials: D
authors.lastname: Moon
authors.forename: Hyung Joon
authors.initials: HJ
authors.lastname: Shin
authors.forename: Kyu Won
authors.initials: KW
authors.lastname: Han
authors.forename: Ji-Ho
authors.initials: JH
authors.lastname: Yoon
mesh_terms: D002244:Carbon / Q000032:analysis; D002245:Carbon Dioxide / Q000032:analysis*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008697:Methane / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D011312:Pressure; D012037:Refuse Disposal; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D014867:Water; D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen; D008697:Methane