Skip to Main content Skip to Navigation
New interface

Optimisation du procédé de séchage d’organogels par le dioxyde de carbone supercritique

Abstract : Drying of organogels, gels composed of an organogelator such as amin acids dissolved in a solvent, leads to the formation of aerogels, very light solids with high porosity. These aerogels are expected to be very good heat insulating materials. Preparation of aerogels includes several steps. This process consists of three steps: preparation of supercritical CO2, drying of the gel in an autoclave with a CO2 flow and CO2-solvent separation carried out in a cascade of three separators. In this study both the last steps were discussed in order to optimize the process parameters. The used solvents are tetralin and toluene. The drying kinetic in the autoclave was studied, three different approaches have been exploited. Tetralin transport in supercritical CO2 within the gel is governed only by the diffusion phenomenon in the first two approaches, although, it is governed by diffusion and convection phenomena in the third approach. The mass transfer equations were solved by two numerical software Matlab and ANSYS-Fluent. It seemed that the third approach gave the most consistent results with experimental results. The understanding of the malfunction reasons of cyclonic separators downstream from the autoclave for the case of toluene required two studies: A CFD hydrodynamic study was used to simulate the fluids transport within the first cyclone separator, using the ANSYS-Fluent software. This study showed that the liquid toluene was not carried over into the gas outlet of the cyclone, indicating that hydrodynamic promotes the separation. For this reason, a thermodynamic study of both solvents, toluene and tetralin was performed. Cyclonic separation was regarded as a simple theoretical stage and simulated with PRO / II software. This study has explained very well the experimental results for both solvents and allowed to optimize the process parameters
Document type :
Complete list of metadata

Cited literature [248 references]  Display  Hide  Download
Contributor : Thèses UL Connect in order to contact the contributor
Submitted on : Wednesday, January 9, 2019 - 10:02:53 AM
Last modification on : Wednesday, November 3, 2021 - 7:09:39 AM


Files produced by the author(s)


  • HAL Id : tel-01752420, version 1



Mouna Lazrag. Optimisation du procédé de séchage d’organogels par le dioxyde de carbone supercritique. Alimentation et Nutrition. Université de Lorraine, 2016. Français. ⟨NNT : 2016LORR0279⟩. ⟨tel-01752420⟩



Record views


Files downloads