Experimental Measurements for the Phase Equilibrium of Methane Hydrate in the Presence of Additives
Date Issued
2009
Date
2009
Author(s)
Kuo, Ping-Chen
Abstract
An experimental apparatus was established in this study to investigate the thermodynamic properties of gas hydrate. The Lw-H-V three-phase equilibrium conditions were measured using the isochoric method. The experimental systems consist of methane + water + additives where the effect of hydrate formation due to various amounts of additives was discussed. The thermodynamic phase equilibrium measurements for methane with pure water had been firstly conducted in this study. Satisfactory agreement with literature data confirmed the validity of our experimental equipments and procedures. Two surfactants (SDS, CTAB) and tert-butanol were used as the additives in this study. It was observed that both surfactants had no significant influence on the thermodynamics of methane hydrate formation. Adding SDS showed a strong promotion on the kinetics of methane hydrate formation while CTAB had a relatively lower effect. It is demonstrated that the addition of tert-butanol had a significant promotion effect on the phase equilibrium of methane hydrate formation. The equilibrium temperature increased 6K at a given pressure with the concentration of 20wt% tert-butanol. Finally, the methane hydrate phase equilibrium data for brine system with the addition of tert-butanol were measured in this study. Tert-butanol again showed promotion effect on the thermodynamics of methane hydrate in seawater environments. The promotion effect in the presence of salt was, however, less than that in pure water.
Subjects
Gas hydrate
phase equilibrium
additive
isochoric method
surfactants
tert-butanol
brine
Type
thesis
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