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Caractérisation de coulis d'hydrates contenant du CO2 appliqués à des systèmes frigorifiques

Abstract : The technology of secondary refrigeration was developed to restrict the mass of harmful refrigerant used in refrigeration systems. In such processes, the cold produced by conventional means is transported by an environment-friendly fluid circulating in a secondary circuit. Liquid-solid two-phase coolants, or slurries, are made of solid particles of a phase change material (PCM) dispersed in a liquid phase. The use of a two-phase coolant enhances the process efficiency by exploiting the latent heat of phase change of the PCM. The aim of this study is to develop a new refrigeration process using gas hydrate slurry as a secondary refrigerant. A particular family of gas hydrates known as semi-clathrates, which are formed from water, gas and a quaternary ammonium or phosphonium salt, were investigated in this study. We first present a pressure-controlled differential scanning calorimetry study of the phase behaviour and enthalpy changes in water-CO2 systems including various semi-clathrate promoting additives : tri-n-butylmethylammonium chloride, tetra-n-butylammonium chloride, tetra-n-butylammonium nitrate and tetra-n-butylphosphonium bromide (TBPB). TBPB-CO2 mixed hydrate has proven to be well suited for usage as a PCM for cold transport in terms of enthalpy and temperature of phase change. In a second step we have investigated the rheology and flow conditions of hydrate slurries formed in the presence of TBPB (with or without CO2) using an experimental device allowing flow rate and pressure drop measurements. After a phenomenological and a rheological study of formation and flowing conditions of TBPB hydrate slurries, the first results of the rheological characterization of mixed TBPB-CO2 hydrate slurries complete this study.
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Contributor : Nadia Mayoufi <>
Submitted on : Sunday, March 6, 2011 - 9:26:46 PM
Last modification on : Monday, May 18, 2020 - 2:37:17 PM
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Nadia Mayoufi. Caractérisation de coulis d'hydrates contenant du CO2 appliqués à des systèmes frigorifiques. Génie des procédés. Ecole Polytechnique X, 2010. Français. ⟨pastel-00573985⟩

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