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Hreiz R.,University of Lorraine | Abdelouahed L.,University of Lorraine | Abdelouahed L.,CNRS Laboratory of Chemical Process Safety | Funfschilling D.,University of Lorraine | Lapicque F.,University of Lorraine
Chemical Engineering Science | Year: 2015

This paper addresses the two-phase flow hydrodynamics in Vertical Plane Electrode Reactors with Gas Electrogeneration, VPERGEs: (1) An experimental investigation of the hydrodynamics in a laboratory-scale VPERGE reactor - for three different current densities - was carried out. Flow visualisation with a high-speed camera, using the gas bubbles as tracers allowed particular flow features to be evidenced. Moreover, thanks to suitable pre- and post- processing tools, the gas velocity fields have been obtained using a PIV algorithm. Measurement errors related to the use of this technique are discussed. The calculated velocity fields provided an overall picture of the flow behaviour, and constitute a data base that can serve for the validation of future numerical results. (2) The two-phase flow was simulated using the two-way momentum coupling Euler-Lagrange CFD approach. Bubbles were considered to be injected slightly away from the electrodes, and not directly at the electrodes surfaces. The shift in the injection position was taken as the average radius of the bubbles. This slight offset of the bubble injection location allowed to obtain a numerical solution that is quasi-independent of the mesh size. CFD results were in good agreement with experimental data, and reproduced key flow features such as spreading of the bubble curtains and bubbles dispersion toward the centre of the reactor. © 2015 Elsevier Ltd. Source

Aboukais A.,University of Lille Nord de France | Aboukais A.,CNRS Laboratory of Chemical Process Safety | Abi-Aad E.,University of Lille Nord de France | Taouk B.,Equipe Catalyse
Materials Chemistry and Physics | Year: 2013

Manganese oxide catalysts supported on titania (TiO2) were prepared by incipient wetness impregnation method in order to elaborate catalysts for total oxidation of toluene and PAHs. These catalysts have been characterized by means of X-ray diffraction (XRD), electron paramagnetic resonance (EPR), temperature programmed reduction (TPR) and temperature programmed desorption (TPD). It has been shown that for the 5%Mn/TiO2 catalyst the reducibility and the mobility of oxygen are higher compared, in one side, to other x%Mn/TiO2 samples and, in another side, to catalysts where TiO2 support was replaced by γ-Al 2O3 or SiO2. It has been shown that the content of manganese loading on TiO2 has an effect on the catalytic activity in the toluene oxidation. A maximum of activity was obtained for the 5%Mn/TiO2 catalyst where the total conversion of toluene was reached at 340 C. This activity seems to be correlated to the presence of the Mn 3+/Mn4+ redox couple in the catalyst. When the Mn content increases, large particles of Mn2O3 appear leading then to the decrease in the corresponding activity. In addition, compared to both other supports, TiO2 seems to be the best to give the best catalytic activity for the oxidation of toluene when it is loaded with 5% of manganese. For this reason, the latter catalyst was tested for the abatement of some PAHs. The light off temperature of PAHs compounds increases with increasing of benzene rings number and with decreasing of H/C ratio. All of PAHs are almost completely oxidized and converted at temperatures lower than 500 C. © 2013 Elsevier B.V. All rights reserved. Source

Ehtash M.,CNRS Laboratory of Chemical Process Safety | Ehtash M.,High Institute for Engineering Profession | Fournier-Salaun M.-C.,CNRS Laboratory of Chemical Process Safety | Dimitrov K.,University of Lille Nord de France | And 2 more authors.
Chemical Engineering Journal | Year: 2014

The removal of phenol from aqueous media such as wastewater, using pertraction in rotating discs contactor is investigated. Preliminary equilibrium extraction study with several organic solvents show that vegetable oils (rapeseed and sunflower oils) can substitute classically volatile organic solvents used as phenol extracting agents. Rapeseed oil allows very efficient removal of phenol from acid aqueous solutions (feed phase) to basic aqueous solution (receiving phase) during batch pertraction studies. In order to optimize operating conditions, the influence of parameters, such as rotating discs speed and initial phenol concentration in the feed phase, on phenol mass transfer is studied. The transport rate of phenol increases with increasing the rotating discs speed. The increase of feed phase phenol concentration has not influence on its transport rate. Semi-continuous pertraction process allows the concentration of phenol. © 2014 Elsevier B.V. Source

Saggadi H.,CNRS Laboratory of Chemical Process Safety | Saggadi H.,CNRS Integrated Transformations of Renewable Matter | Polaert I.,CNRS Laboratory of Chemical Process Safety | Luart D.,CNRS Integrated Transformations of Renewable Matter | And 3 more authors.
Catalysis Today | Year: 2015

Abstract Microwave heating is an interesting technology for chemical engineering, since it can provide effective volumetric heating of the reaction medium and reduce energy costs. Many commercially available laboratory-scale microwave reactors have already been used to carry out chemical reactions on a small scale (a few milliliters), and at high temperatures and pressures. Some research has been undertaken to scale-up microwave processes and make them suitable for a larger scale production. Indeed, combining wave propagation through the walls of a reactor with resistance toward high pressure and temperature as well, is not an easy task. For these reasons, this work focuses on the development of a pilot scale microwave apparatus used for the heating of larger reaction volumes under pressure, and under controlled conditions. The specially designed microwave apparatus allows chemical reactions in batch or continuous mode. The applicator operates in single mode enabling a uniform electromagnetic field, and well controlled operating conditions. The main advantage of the setup is the quite large reactor volume that permits either relatively long residence times or relatively high mass flowrates (up to 1 kg/h). The developed microwave apparatus was then used for quinoline synthesis from glycerol via a modified Skraup reaction. The major advantage of our system is the ability to carry out continuous chemical synthesis, at a large pilot scale, and high temperatures (200-220 °C), while ensuring a better control of the pressure (max. 19 bar) through the control of the power absorbed by the reaction medium. © 2014 Elsevier B.V. Source

Saggadi H.,CNRS Integrated Transformations of Renewable Matter | Saggadi H.,CNRS Laboratory of Chemical Process Safety | Luart D.,CNRS Integrated Transformations of Renewable Matter | Thiebault N.,CNRS Integrated Transformations of Renewable Matter | And 4 more authors.
RSC Advances | Year: 2014

An efficient "green" modified Skraup reaction in neat water was developed using inexpensive, abundant and environmentally-friendly glycerol under microwave irradiation conditions. Starting from aniline derivatives, various quinolines were obtained in 10-66% yields. The use of nitroaniline led to the corresponding phenanthrolines in 15-52% yields, respectively. This journal is © the Partner Organisations 2014. Source

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