References of "Léonard, Angélique"
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See detailTowards the production of carbon xerogel monoliths by optimizing convective drying conditions
Job, Nathalie ULg; Sabatier, Françoise; Pirard, Jean-Paul ULg et al

in Carbon (2006), 44(12), 2534-2542

Resorcinol-formaldehyde hydrogels prepared at various resorcinol/sodium carbonate ratios, R/C, were convectively air dried. The influence of the drying operating conditions, i.e. air temperature and ... [more ▼]

Resorcinol-formaldehyde hydrogels prepared at various resorcinol/sodium carbonate ratios, R/C, were convectively air dried. The influence of the drying operating conditions, i.e. air temperature and velocity, on the pore texture, shrinkage and cracking of the dried gels were investigated. Shrinkage was found to be isotropic. The shrinkage behaviour and the textural properties of the gels are independent of the drying operating conditions, but are completely determined by the value of the synthesis variables. The analysis of the drying kinetics shows two main drying periods. During the first phase, shrinkage occurs and the external surface of the material remains completely wet: heat and mass transfers are limited by external resistances located in a boundary layer. When shrinkage stops, the second period begins: the evaporation front recedes inside the solid and internal transfer limitations prevail. The drying time can be reduced by increasing the air temperature and/or velocity, but the temperature increase is limited when monolithicity is required, especially when the pores are small. For example, at a temperature of 160 degrees C and a velocity of 2 m/s, about 1 h is needed to dry a 2.8 cm in diameter and 1 cm in height cylinder containing macropores (pore width > 50 nm after drying). The same cylinder presenting small mesopores (pore width = 10-15 nm after drying) requires 20 h at 30 degrees C and 2 m/s to reach complete dryness without the development of cracks. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailStudy of organic and water vapours adsorption on carbon filters by X-ray microtomography
Léonard, Angélique ULg; Blacher, Silvia ULg; Marchot, Pierre ULg et al

in Fourth International Symposium on Process Tomography in Poland, 2006, Varsóvia (2006, September)

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See detailVarious applications of X-ray microtomography in chemical engineering
Léonard, Angélique ULg; Blacher, Silvia ULg; Lodewyckx, Peter et al

Conference (2006, September)

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See detailModelling of the convective drying of resorcinol-formaldehyde resins: influence of the drying conditions on the induces stress tensor
Léonard, Angélique ULg; Crine, Michel ULg; Jomaa, Wahbi

in Farkas, Istvan (Ed.) Drying 2006, the Proceedings of the 15th International Drying Symposium,Budapest, Hungary, 20-23 August 2006, Vol. A (2006, August)

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See detailUse of X-ray tomography to study the influence of back mixing on the convective drying of sludges in a fixed bed
Léonard, Angélique ULg; Meneses, Eustedio; Le Trong, Emmanuel et al

in Farkas, Istvan (Ed.) Drying 2006, the Proceedings of the 15th International Drying Symposium, Budapest, Hungary, 20-23 August 2006, Vol B. (2006, August)

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See detailStudy of the dynamics of water adsorption on activated carbon by a combination of high resolution x-ray microtomography and breakthrough measurements
Lodewyckx, Peter; Wullens, Hilda; Léonard, Angélique ULg et al

in Proceedings of Carbon 2006 (2006, July)

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See detailThermo-hygro-mechanical modelling of the convective drying of resorcinol-formaldehyde xerogel monoliths
Léonard, Angélique ULg; Crine, Michel ULg; Jomaa, Wahbi

in Proceedings of Carbon 2006 (2006, July)

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See detailTechniques tomographiques : des instruments de mesure de choix en génie chimique
Toye, Dominique ULg; Marchot; Léonard, Angélique ULg et al

Scientific conference (2006, May 17)

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See detailPd-Ag/SiO2 xerogel catalyst forming by impregnation on alumina foams
Alié, Christelle ULg; Ferauche, Fabrice; Léonard, Angélique ULg et al

in Chemical Engineering Journal (2006), 117(1), 13-22

A Pd-Ag/SiO2 xerogel catalyst prepared in one step by sol-gel process has been entrapped in cylindrical porous alumina foams of three different pore sizes in order to shape the catalyst under the ... [more ▼]

A Pd-Ag/SiO2 xerogel catalyst prepared in one step by sol-gel process has been entrapped in cylindrical porous alumina foams of three different pore sizes in order to shape the catalyst under the appropriate form with suitable mechanical resistance to be used in an industrial fixed bed reactor. After drying, calcination and reduction, the Pd-Ag/SiO2 xerogel catalyst pellets are immobilized inside the open porosity of the alumina foam. The localization of the xerogel catalyst in the alumina foams has been studied by X-ray tomography. The three-dimensional porous structure was reconstructed from the consecutive cross-sections obtained by this technique. This method shows that the Pd-Ag/SiO2 xerogel catalyst is uniformly dispersed inside the porosity of the alumina foams. Activity and selectivity of Pd-Ag/SiO2 xerogel catalyst reference or catalyst entrapped in alumina foams have been studied for selective hydrodechlorination of 1,2-dichloroethane into ethylene. The specific reaction rate obtained with catalyst entrapped in alumina foams is smaller than the one obtained from corresponding catalyst powders. The catalytic activity decrease observed for Pd-Ag/SiO2 xerogel catalyst entrapped in porous alumina foams most probably arises from diffusional limitations inside the porous texture of the alumina foams. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailTechniques tomographiques : des outils de choix pour l’étude des réacteurs polyphasiques
Toye, Dominique ULg; Fransolet, Emmanuelle; Léonard, Angélique ULg et al

Conference (2006, March 14)

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See detailCaractérisation de matériaux poreux par analyse d'images 3D
Blacher, Silvia ULg; Gommes, Cédric ULg; Léonard, Angélique ULg et al

Conference (2006, February)

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See detailSynthesis optimization of organic xerogels produced from convective air-drying of resorcinol-formaldehyde gels
Job, Nathalie ULg; Panariello, Fabian; Marien, José ULg et al

in Journal of Non-Crystalline Solids (2006), 352(1), 24-34

Resorcinol-formaldehyde gels were produced at 50, 70 and 90 degrees C and with three different R/C ratios (500, 1000 and 2000). The effect of these variables combined with that of aging time was studied ... [more ▼]

Resorcinol-formaldehyde gels were produced at 50, 70 and 90 degrees C and with three different R/C ratios (500, 1000 and 2000). The effect of these variables combined with that of aging time was studied in order to optimize the synthesis conditions. The convective air-drying process was used, and the drying duration was studied with regard to the synthesis conditions. The aging time has no effect on the pore texture after 24 h at 90 degrees C or 48 h at 70 C, whatever the R/C value. The synthesis-aging step can be shortened by increasing the temperature. Nevertheless, the pore size tends then to decrease, especially when R/C is high, but this can be counterbalanced by increasing R/C. Moreover, bubbles often appear in the gel at high synthesis temperature, which limits the temperature to about 70 degrees C in the case of monolithic parts. At 70 degrees C and with an air velocity of 2 m/s, the elimination of 90% of the solvent requires 1 h drying when the pore size reaches 400-600 nm, 2.5 h for 50 nm wide pores and 3 h when the pore size decreases to 15-20 nm. The drying duration does not exceed 8 h in all cases and could be shortened by increasing the temperature at the end of the process. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailUse of x-ray microtomography to visualise dynamic adsorption of organic vapour and water vapour on activated carbon
Lodewyckx, Peter; Blacher, Silvia ULg; Léonard, Angélique ULg

in Adsorption (2006), 12(1), 19-26

X-ray microtomography coupled with image analysis was used to quantify the adsorption of vapours on activated carbon beds. This technique was tested using three different challenges: CCl4, water vapour ... [more ▼]

X-ray microtomography coupled with image analysis was used to quantify the adsorption of vapours on activated carbon beds. This technique was tested using three different challenges: CCl4, water vapour and a mixture of water- and organic vapour. It is shown that the used technique allows determining the adsorption front progress in the case of organic vapour and mixture of water and organic vapour whereas the existence of this front was not so obvious in the case of water vapour. Experimental results obtained for organic vapours were interpreted on the basis of the Wheeler-Jonas equation: a good agreement was found between experimental and theoretical breakthrough times. [less ▲]

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See detailThe porous structure of biodegradable scaffolds obtained with supercritical CO2 as foaming agent
Blacher, Silvia ULg; Calberg, Cédric ULg; Kerckhofs, Greet ULg et al

in Studies in Surface Science and Catalysis (2006), 160

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See detailThe porous structure of biodegradable scaffolds obtained with supercritical CO(2) as foaming agent
Blacher, Silvia ULg; Calberg, Cédric ULg; Kerckhofs, Greet ULg et al

in Studies in Surface Science and Catalysis (2006), 160

Poly(epsilon-caprolactone) foams were prepared, via a batch process, by using supercritical CO(2) as foaming agent. Their porous structure was characterized through helium and mercury pycnometry, scanning ... [more ▼]

Poly(epsilon-caprolactone) foams were prepared, via a batch process, by using supercritical CO(2) as foaming agent. Their porous structure was characterized through helium and mercury pycnometry, scanning electron microscopy (SEM) and X-ray microtomography observations coupled with image analysis. The pore size distributions obtained by these two latter techniques show that the pore structure is more homogeneous when the foaming process is performed under a high CO(2) saturation pressure (higher than 250 bars). [less ▲]

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