ie7b01093_si_001.pdf (125.73 kB)
Hydrate Phase Equilibrium of CH4+N2+CO2 Gas Mixtures and Cage Occupancy Behaviors
journal contribution
posted on 2017-06-21, 00:00 authored by You-Hong Sun, Sheng-Li Li, Guo-Biao Zhang, Wei Guo, You-Hai ZhuMethane, nitrogen, and carbon dioxide
coexist after the injection
of CO2/N2 mixture into CH4 hydrate.
For a better understanding of CH4 recovery and CO2 sequestration by gas exchange involving N2, the hydrate
phase equilibrium of CH4/N2/CO2 ternary
gas mixtures in pure water system was determined in a sapphire cell
using the pressure-search method under isothermal conditions. The
hydrate equilibrium data were analyzed with respect to the concentration
of CH4 and the ratio of N2/CO2. The
cage occupancies of CH4, N2, and CO2 were calculated by Chen–Guo hydrate model and CSMHYD program.
The result revealed that the cage-specific guest distributions and
preferential partitioning of guest molecules in cages were involved
in the formation of mixed gas hydrates. The enthalpy of the ternary
hydrates was calculated using the Clausius–Clapeyron equation.
It was deduced that the enthalpy of the mixed hydrates was changed
with the occupancy of CO2 molecules in large cavities.