Cyclic operation strategies in trickle beds and electrical capacitance tomography imaging of filtration dynamics / Mohsen Hamidipour in Industrial & engineering chemistry research, Vol. 49 N° 3 (Fevrier 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 3 (Fevrier 2010) . - pp. 934–952 Titre : Cyclic operation strategies in trickle beds and electrical capacitance tomography imaging of filtration dynamics Type de document : texte imprimé Auteurs : Mohsen Hamidipour, Auteur ; Faïçal Larachi, Auteur ; Zbigniew Ring, Auteur Année de publication : 2010 Article en page(s) : pp. 934–952 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Cyclic--Trickle Beds--Electrical Capacitance--Tomography--Imaging--Filtration Dynamics Résumé : The dynamics of propagating liquid pulsations generated via various cyclic operation strategies in trickle beds was monitored through electrical capacitance tomography (ECT) for gas and liquid superficial velocities in the range of trickle flow regime. The characteristics of ON−OFF liquid, ON−OFF gas, and gas/liquid alternating cyclic operations were compared in terms of mean liquid holdup, pressure drop, pulsation intensity, pulsation propagation velocity, and spatial maldistribution maps of liquid holdup and liquid pulsation propagation velocity. The morphological features of liquid holdup pulsations as a function of cycle frequency were characterized in terms of breakthrough, plateau, and decay times. Gas/liquid alternating cyclic strategy was shown to produce long-lived liquid pulsations under the applied operating conditions and thus could be viewed as a new process intensification means to achieve uniform phase holdup and velocity distributions. In ON−OFF liquid cyclic operation, pulsation velocity did not increase along the bed unlike the ON−OFF gas and gas/liquid alternating cyclic modes where increased pulsation velocities were able to give rise to pulse flow regime. The gas/liquid alternating cyclic operation resulted in the shortest breakthrough and decay times and the longest plateau time, thus approaching the ideal square-shaped inlet pulsations for symmetrical splits. ECT imaging was also used to scrutinize the dynamics of local deposition of fines in trickle beds fed with kaolin suspensions under the three cyclic operations. Data revealed that applying ON−OFF gas and gas/liquid alternating cyclic methods resulted in significant reduction of fines deposition. This suggests new practical solutions for possible industrial implementation of self-cleaning modulation strategies of trickle beds subject to unwanted filtration during suspension flows. Note de contenu : Bibiogr. ISSN : 0885-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900605b [article] Cyclic operation strategies in trickle beds and electrical capacitance tomography imaging of filtration dynamics [texte imprimé] / Mohsen Hamidipour, Auteur ; Faïçal Larachi, Auteur ; Zbigniew Ring, Auteur . - 2010 . - pp. 934–952. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 3 (Fevrier 2010) . - pp. 934–952 Mots-clés : Cyclic--Trickle Beds--Electrical Capacitance--Tomography--Imaging--Filtration Dynamics Résumé : The dynamics of propagating liquid pulsations generated via various cyclic operation strategies in trickle beds was monitored through electrical capacitance tomography (ECT) for gas and liquid superficial velocities in the range of trickle flow regime. The characteristics of ON−OFF liquid, ON−OFF gas, and gas/liquid alternating cyclic operations were compared in terms of mean liquid holdup, pressure drop, pulsation intensity, pulsation propagation velocity, and spatial maldistribution maps of liquid holdup and liquid pulsation propagation velocity. The morphological features of liquid holdup pulsations as a function of cycle frequency were characterized in terms of breakthrough, plateau, and decay times. Gas/liquid alternating cyclic strategy was shown to produce long-lived liquid pulsations under the applied operating conditions and thus could be viewed as a new process intensification means to achieve uniform phase holdup and velocity distributions. In ON−OFF liquid cyclic operation, pulsation velocity did not increase along the bed unlike the ON−OFF gas and gas/liquid alternating cyclic modes where increased pulsation velocities were able to give rise to pulse flow regime. The gas/liquid alternating cyclic operation resulted in the shortest breakthrough and decay times and the longest plateau time, thus approaching the ideal square-shaped inlet pulsations for symmetrical splits. ECT imaging was also used to scrutinize the dynamics of local deposition of fines in trickle beds fed with kaolin suspensions under the three cyclic operations. Data revealed that applying ON−OFF gas and gas/liquid alternating cyclic methods resulted in significant reduction of fines deposition. This suggests new practical solutions for possible industrial implementation of self-cleaning modulation strategies of trickle beds subject to unwanted filtration during suspension flows. Note de contenu : Bibiogr. ISSN : 0885-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900605b

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Monitoring filtration in trickle beds using electrical capacitance tomography / Mohsen Hamidipour in Industrial & engineering chemistry research, Vol. 48 N°3 (Février 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1140–1153 Titre : Monitoring filtration in trickle beds using electrical capacitance tomography Type de document : texte imprimé Auteurs : Mohsen Hamidipour, Auteur ; Faïçal Larachi, Auteur ; Zbigniew Ring, Auteur Année de publication : 2009 Article en page(s) : p. 1140–1153 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Trickle Beds -- Filtration Oil Hydrocarbon Résumé : Experiments were carried out to monitor the evolution of the deposition of fine particles in trickle-bed reactors during the flow of nonpolar hydrocarbon oil-like liquid suspensions using electrical capacitance tomography (ECT) imaging. The accuracy of the ECT rendition was validated in the pristine (i.e., deposit-free) bed state by comparing the liquid holdup measurements from ECT with the liquid holdup from residence time distribution (RTD) measurements. The pulse-flow characteristics (pulse velocity and frequency) estimated from the ECT signals were in agreement with existing literature data. For filtration experiments, the effects of the initial liquid suspension distribution, the gas and liquid superficial velocities, and single-phase flow (i.e., zero gas velocity) on the structure of the deposition in the bed were studied. ECT imaging successfully tracked the unsteady-state progression of bed plugging throughout the trickle bed. It was found that increasing the liquid or gas superficial velocity resulted in increased local deposition. The transition, due to deposition, from trickle to pulse flow was also determined from ECT. In the case of stagnant gas, a filter cake formed on top of the bed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800810t [article] Monitoring filtration in trickle beds using electrical capacitance tomography [texte imprimé] / Mohsen Hamidipour, Auteur ; Faïçal Larachi, Auteur ; Zbigniew Ring, Auteur . - 2009 . - p. 1140–1153. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1140–1153 Mots-clés : Trickle Beds -- Filtration Oil Hydrocarbon Résumé : Experiments were carried out to monitor the evolution of the deposition of fine particles in trickle-bed reactors during the flow of nonpolar hydrocarbon oil-like liquid suspensions using electrical capacitance tomography (ECT) imaging. The accuracy of the ECT rendition was validated in the pristine (i.e., deposit-free) bed state by comparing the liquid holdup measurements from ECT with the liquid holdup from residence time distribution (RTD) measurements. The pulse-flow characteristics (pulse velocity and frequency) estimated from the ECT signals were in agreement with existing literature data. For filtration experiments, the effects of the initial liquid suspension distribution, the gas and liquid superficial velocities, and single-phase flow (i.e., zero gas velocity) on the structure of the deposition in the bed were studied. ECT imaging successfully tracked the unsteady-state progression of bed plugging throughout the trickle bed. It was found that increasing the liquid or gas superficial velocity resulted in increased local deposition. The transition, due to deposition, from trickle to pulse flow was also determined from ECT. In the case of stagnant gas, a filter cake formed on top of the bed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800810t

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