Published online by Cambridge University Press: 03 February 2016
We report in this study the dissociation conditions for the carbon dioxide hydrate in the presence of additive materials. We measured the hydrate-water-vapor (H-Lw-V) three-phase equilibrium data using the isochoric method. Examples of these phase equilibrium data for the additive materials of 1,3,5-trioxane, 2,5-dihydrofuran, 1,3-dioxolane, and 3,4-dihydro-2H-pyran are presented. The experimental pressure range is from 1.6 to 3.3 MPa, and the concentration of each additive is at 10 wt%. The experimental results indicate that cyclic ethers of 1,3,5-trioxane, 2,5-dihydrofuran, and 1,3-dioxolane promote the formation of carbon dioxide hydrate. Their promotion effects at a given pressure are up to 5 K, 6.9 K, and 4.2 K, respectively, The additive material of 3,4-dihydro-2H-pyran, however, shows the inhibitor behavior. The average inhibition effect is about 1.3 K at a given pressure.