Experimental determination and modeling of structure II hydrates in mixtures of methane plus water plus 1,4-dioxane

Citation
Md. Jager et al., Experimental determination and modeling of structure II hydrates in mixtures of methane plus water plus 1,4-dioxane, FLU PH EQUI, 165(2), 1999, pp. 209-223
Citations number
23
Categorie Soggetti
Physical Chemistry/Chemical Physics","Chemical Engineering
Journal title
FLUID PHASE EQUILIBRIA
ISSN journal
03783812 → ACNP
Volume
165
Issue
2
Year of publication
1999
Pages
209 - 223
Database
ISI
SICI code
0378-3812(19991125)165:2<209:EDAMOS>2.0.ZU;2-Y
Abstract
Hydrate phase equilibrium conditions were measured with a Cailletet apparat us in the pressure range 2 < 14 MPa. The investigated 1,4-dioxane concentra tions were 1, 2, 5, 7, 10, 20 and 30 mol% relative to water. The results sh ow that adding 1,4-dioxane up to concentrations of 6 mol%, about the stoich iometric ratio of large sII cages to water (1/17), reduced the equilibrium pressure of hydrate formation. Adding I,4-dioxane beyond 6 mol% caused a sl ow increase of the equilibrium pressures. The hydrate phase equilibria data were modeled as equilibrium between a liquid phase of water and 1,4-dioxan e, with a small amount of methane, and a sII hydrate of 1,4-dioxane and met hane. The chemical potential of the hydrate phase was described using the v an der Waals and Platteeuw theory. Activity coefficients of the liquid phas e were calculated by a van Laar relation, based on literature 1,4-dioxane water VLE data. The predicted equilibrium pressures calculated were within 5% of the data up to a concentration of 20 mol% 1,4-dioxane relative to wa ter. (C) 1999 Elsevier Science B.V. All rights reserved.