Combined use of PEPT and ERT in the study of aluminum hydroxide precipitation / Iwan Edwards in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 1019–1028 Titre : Combined use of PEPT and ERT in the study of aluminum hydroxide precipitation Type de document : texte imprimé Auteurs : Iwan Edwards, Auteur ; Sean A. Axon, Auteur ; Mostafa Barigou, Auteur ; Hugh Stitt, Auteur Année de publication : 2009 Article en page(s) : p 1019–1028 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Aluminum Hydroxide--Study Résumé : The application of multimodal tomographic techniques to the in situ study of the semibatch precipitation of aluminum hydroxide, an industrially important alumina precursor, has been developed. For the first time Electrical Resistance Tomography (ERT) and Positron Emission Particle Tracking (PEPT) have been used concomitantly to study precipitation and hydrodynamics. This combination of techniques allows a step change in our ability to understand industrial precipitation processes. The semibatch precipitation of aluminum hydroxide was investigated in a stirred vessel operated with different configurations. Mixing conditions during semi batch precipitation have been shown to determine particle properties. Variables such as impeller design, power input, and feed location were used to provide different mixing conditions at the feed point where the reagents contact and precipitation takes place. The mixing performance during precipitation can be analyzed using ERT, with information of how the feed plume is dispersed under different mixing conditions. The flow conditions in the feed region can be characterized using PEPT. Together, the techniques can establish how the feed plume is dissipated into the bulk fluid. [article] Combined use of PEPT and ERT in the study of aluminum hydroxide precipitation [texte imprimé] / Iwan Edwards, Auteur ; Sean A. Axon, Auteur ; Mostafa Barigou, Auteur ; Hugh Stitt, Auteur . - 2009 . - p 1019–1028. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p 1019–1028 Mots-clés : Aluminum Hydroxide--Study Résumé : The application of multimodal tomographic techniques to the in situ study of the semibatch precipitation of aluminum hydroxide, an industrially important alumina precursor, has been developed. For the first time Electrical Resistance Tomography (ERT) and Positron Emission Particle Tracking (PEPT) have been used concomitantly to study precipitation and hydrodynamics. This combination of techniques allows a step change in our ability to understand industrial precipitation processes. The semibatch precipitation of aluminum hydroxide was investigated in a stirred vessel operated with different configurations. Mixing conditions during semi batch precipitation have been shown to determine particle properties. Variables such as impeller design, power input, and feed location were used to provide different mixing conditions at the feed point where the reagents contact and precipitation takes place. The mixing performance during precipitation can be analyzed using ERT, with information of how the feed plume is dispersed under different mixing conditions. The flow conditions in the feed region can be characterized using PEPT. Together, the techniques can establish how the feed plume is dissipated into the bulk fluid.

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From laboratory to field tomography / Zeljko Kuzeljevic in Industrial & engineering chemistry research, Vol. 50 N° 17 (Septembre 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 17 (Septembre 2011) . - pp. 9890-9900 Titre : From laboratory to field tomography : data collection and performance assessment Type de document : texte imprimé Auteurs : Zeljko Kuzeljevic, Auteur ; Milorad Dudukovic, Auteur ; Hugh Stitt, Auteur Année de publication : 2011 Article en page(s) : pp. 9890-9900 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Tomography Résumé : In field tomography, the total number of scan lines collected during imaging is usually limited. At the same time, the demands on the technique regarding resolution are low, corresponding to diagnostic purposes (e.g., presence or absence of maldistribution). In this study, we investigate the level of information needed for purpose of field diagnostics when using a fan beam tomography scanner. We utilize the theoretical framework of Fisher information content to examine dependence between projection data collection methodology and image quality. The findings are substantiated by experimental results obtained on suitable phantom designed to mimic maldistribution in packed bed. The performance of expectation-maximization and alternating-minimization image reconstruction algorithms for varying number of scan lines used is compared. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24483632 [article] From laboratory to field tomography : data collection and performance assessment [texte imprimé] / Zeljko Kuzeljevic, Auteur ; Milorad Dudukovic, Auteur ; Hugh Stitt, Auteur . - 2011 . - pp. 9890-9900. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 17 (Septembre 2011) . - pp. 9890-9900 Mots-clés : Tomography Résumé : In field tomography, the total number of scan lines collected during imaging is usually limited. At the same time, the demands on the technique regarding resolution are low, corresponding to diagnostic purposes (e.g., presence or absence of maldistribution). In this study, we investigate the level of information needed for purpose of field diagnostics when using a fan beam tomography scanner. We utilize the theoretical framework of Fisher information content to examine dependence between projection data collection methodology and image quality. The findings are substantiated by experimental results obtained on suitable phantom designed to mimic maldistribution in packed bed. The performance of expectation-maximization and alternating-minimization image reconstruction algorithms for varying number of scan lines used is compared. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24483632

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