Kinetic and thermodynamic study of gas hydrates in porous media : application to gas hydrates-bearing sediments and cold storage process.

Étude cinétique et thermodynamique des hydrates de gaz en milieu poreux : application aux hydrates sédimentaires et aux procédés de stockage du froid.

Author(s) : BENMESBAH F. D.

Type of monograph: Thesis

Summary

Gas hydrates are addressed in a wide variety of scientific topics, including geosciences and industrial processes such as cold production and storage. The study of gas hydrates formation and dissociation in porous media is essential to better understand the dynamics of gas hydrates in natural hydrate-bearing sediments and to optimize cold storage processes. The purpose of this study is to understand the effect of "key" parameters such as water saturation, particle size, gas injection flowrate and the morphology of the porous media on hydrate formation kinetics and storage capacity in porous media. To meet this objective, two experimental devices were used to combine and cross the knowledge and methodologies developed in the two disciplines, Geosciences and Process Engineering, in order to generate complementary data on kinetics and thermodynamics, and thus better characterize the hydrate formation process in porous media. The first device is a high pressure cell, the second is a differential thermal analysis cell. The results obtained showed a decreasing trend in the induction time of hydrate formation with increasing gas flowrate. This trend was not observed when varying water saturation, particle size, and the morphology of the porous media. These parameters showed a small influence on the induction time. The values obtained confirm the stochastic nature of hydrate nucleation. A heterogeneous distribution of hydrates in the porous media was observed in the pressure path during the experiments in the high-pressure cell. This hydrate distribution appears to be as stochastic as the induction time, thus preventing total water consumption even under conditions of excess gas. Through all the experiments, it has been shown that the amount of hydrates formed depends strongly on the interfacial contact between gas and liquid phases. The latter is linked to the spatial distribution of these two phases in the porous media. The presence of mesoporous volume favors the gas-liquid contact, which has resulted in higher performance in terms of the amount of hydrates formed compared to a porous media without internal pore volumes. In addition, it was shown by comparing the results of the two experimental devices that the amount of hydrate formed also depends on the system and experimental approach used.

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Pages: 225 p.

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Details

  • Original title: Étude cinétique et thermodynamique des hydrates de gaz en milieu poreux : application aux hydrates sédimentaires et aux procédés de stockage du froid.
  • Record ID : 30032278
  • Languages: French
  • Subject: Technology
  • Publication: Sorbonne université - Antony - France
  • Publication date: 2021/03/24

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