Dissociation Data and Thermodynamic Modeling of Clathrate Hydrates of Ethene, Ethyne, and Propene

Abstract

Ethene, ethyne, and propene are common and important industrial gases which are known to form hydrates. There exists in the open literature some hydrate dissociation data for simple hydrates of the three hydrocarbons. Unfortunately the data reported in literature are in some instances very limited, and the data sets are not always in agreement with each other. To evaluate the hydrate data for these hydrocarbons, new hydrate dissociation data were measured and are compared to that in the literature. Measurements for ethyne were undertaken in the temperature and pressure ranges of (273.2 to 285.5) K and (0.614 to 2.467) MPa, respectively. The temperature and pressure ranges for the propene measurements were (273.5 to 274.4) K and (0.492 to 0.613) MPa, respectively. The solid solution theory of van der Waals and Platteeuw, together with the Valderama–Patel–Teja equation of state and the non-density-dependent mixing rules were used to model the experimental hydrate dissociation conditions. Model predictions were found to be in satisfactory agreement with the newly reported data, as well as independent measurements for the ethyne + water and ethene + water systems. However, only a fair agreement is observed when the modeled data is compared to propene hydrate dissociation data found in the literature.

Experimental measurement and thermodynamic modelling of hydrate phase equilibrium conditions for krypton + n -butyl ammonium bromide aqueous solution

“…The isochoric pressure search method was used to perform the hydrate dissociation measurements for the krypton + TBAB + water system [48][49][50][51]. At the start of the measurements, the cell was evacuated using an Edwards vacuum pump to a pressure of 0.0003 MPa for approximately 30 minutes to remove air and any contaminants from previous experiments.…”

“…A step-change of 0.1 K per hour was used in the vicinity of the dissociation point. The point corresponding to the sharp change of the slope of the pressure−temperature plot is taken to be the final dissociation point [46][47][48][49][50][51]. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 8 Figure 1 shows an example of the cooling and heating curve for the determination of the hydrate dissociation point.…”

Thermodynamic model of phase equilibria of tetrabutyl ammonium halide (fluoride, chloride, or bromide) plus methane or carbon dioxide semiclathrate hydrates

“…Gas hydrate was regarded as the reason for blockage of natural gas transportation pipelines [2] since 1934. In modern society, more attention was focused on gas hydrate, as it became a promising medium for many positive applications, such as gas storage [3,4], gas separation [5,6], energy storage [7], water desalination [8], separation of close-boiling point compounds [9][10][11][12] and so on. However, the condition of high pressure and low temperature required for the hydrate formation is one of the greatest obstacles to realize these hydrate-based technologies.…”

Hydrate-based heavy metal separation from aqueous solution

“…Tumba et al . conducted separation experiments of close-boiling point compounds according to the varying conditions under which each component forms hydrates 9 10 11 . In addition, refrigerant hydrates have high cold storage capacities and efficiencies, which led Hashemi et al .…”