Effect of sample size on the mechanical stresses induced during the convective drying of highly shrinking materials

in Proceedings of the joint conference of AFSIA and Drying Working group of EFCE at Casino Municipal Biarritz, France, 24th and 25th May, 2007 (2007, May)

Rheological determination of the sol-gel transition during the aqueous synthesis of resorcinol-formaldehyde resins

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2007), 293(1-3), 224-228

The sol-gel transition of organic gels prepared by polycondensation of resorcinol (R) with formaldehyde (F) in presence of sodium carbonate (C) was monitored by small amplitude oscillatory measurements ... [more ▼]

The sol-gel transition of organic gels prepared by polycondensation of resorcinol (R) with formaldehyde (F) in presence of sodium carbonate (C) was monitored by small amplitude oscillatory measurements, at a single frequency. The gelation time (t(g)) was determined from the evolution of the storage (G) and loss (G") moduli versus time. The influence of two synthesis variables, the resorcinol/sodium carbonate ratio (R/C) and the synthesis temperature (7), was investigated. The gelation time was found to decrease with increasing synthesis temperature and decreasing R/C ratio. The apparent activation energy of the reactional system leading to the gelation, calculated from the gelation times obtained between 50 and 90 degrees C, was found to be close to 80 kJ mol(-1) and independent of the R/C ratio. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

Lattice Boltzmann 3D flow simulations in a hepa aerosol filter, on a computing grid

Conference (2007)

Modélisation d'un écoulement diphasique au sein d'un empilage structuré

in SFGP (Ed.) Récents Progrès en Génie des procédés - N°96 - Des réponses industrielles pour une société en mutation - Actes du 11ème Congrès de la Société française de Génie des procédés - 9-11 octobre 2007, Saint Etienne, France (2007)

In situ measurements of the static liquid holdup in Katapak-SP12 (TM) packed column using X-ray tomography

in Chemical Engineering Science (2007), 62(21), 6076-6080

Static liquid holdup was determined in situ, in a column packed with Katapak-SP12 (TM) elements, using a non-intrusive X-ray tomographic technique. Experiments were performed in a 10 cm diameter PVC ... [more ▼]

Static liquid holdup was determined in situ, in a column packed with Katapak-SP12 (TM) elements, using a non-intrusive X-ray tomographic technique. Experiments were performed in a 10 cm diameter PVC column with the air-water system. The technique allows a local determination of the various liquid holdup as well as of the capillary height, without dismantling the elements. Results are in good agreement with correlations proposed in the literature. (C) 2007 Elsevier Ltd. All rights reserved. [less ▲]

X-ray microtomography: a useful method to study the dynamics of organic and water vapours adsorption on carbon filters

in 2006 AIChE Annual Meeting (2006, November)

Towards the production of carbon xerogel monoliths by optimizing convective drying conditions

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 ▲]

Use of x-ray microtomography coupled to image analysis for cracks detection and quantification

Poster (2006, September)

Simulation of transport processes in fiber filters: Combining a lattice Boltzmann CFD method and a particle tracking method

Poster (2006, September)

Modelling of the convective drying of resorcinol-formaldehyde resins: influence of the drying conditions on the induces stress tensor

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