References of "Toye, Dominique"
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See detailBiofilm formation on metal structured packing for the production of high added value biomolecules
Zune, Quentin ULg; Zune, Quentin ULg; Toye, Dominique ULg et al

in Récents Progrès en Génie des Procédés (2013)

Many white biotechnology bioprocesses apply techniques from chemical engineering based on bioreactors with mechanical stirring system commonly employed in pharmaceutical sector, food industry or energy ... [more ▼]

Many white biotechnology bioprocesses apply techniques from chemical engineering based on bioreactors with mechanical stirring system commonly employed in pharmaceutical sector, food industry or energy field (Dasilva, 2004). As in chemical engineering, scale-up of these bioprocesses induces physicochemical constraints that affect physiological pathways and decrease performances. In this context, it is essential to think new bioprocesses better suited to physiology of microorganisms, minimizing physicochemical constraints. The aim of this work consists to use stainless steel structured packing (SSP) with high specific area (500-750 m²/m³) as inert support for biomass immobilization in order to produce high added value biomolecules. These bioreactors are biocatalysts in which microbial system is immobilized biomass on the form of a biofilm performing bioconversion of a substrate into a specific product (Rosche, 2009). In this study, an experimental setting containing a SSP reproduces solid-state fermentation (SSF) like conditions. Two well known microorganisms for their ability to form biofilm and secrete metabolites are tested in the experimental setting : Bacillus subtilis for its lipopeptides and Aspergillus oryzae for its glucoamylase. Effectiveness of the bioprocess in term of dynamic of the excretion of the target biomolecule is compared with a classical submerged culture (SmF). For lipopeptides production from B. subtilis, SSP is located in a 20L bioreactor continuously aspersed by liquid medium required to the growth of the biofilm. In the case of A. oryzae, the SSP is partially immerged in a 250 mL shake flask. X-ray tomography of the SSP allows non-invasive visualization and quantification of biofilm repartition inside the support. Implementation of SSP permits almost total immobilization of biomass on the form of a mono-species biofilm to the detriment of the liquid phase. Processing of images obtained by X-ray tomography of the SSP provides relevant information for the optimization of the bioprocess. For both microorganism species, results indicate the influence of parameters such as hydrodynamics, aeration rate and microorganism specificity, on the biofilm morphology inside the support and the performances of the bioprocess. SSF-like conditions in the experimental setting lead to technologic progress, such as absence of foam formation, persistence of the microbial system, and improve the dynamic of metabolites excretion compared with conditions imposed by the submerged culture. Further experiment will consider hydrodynamics aspects and amount of carbon source on effectiveness of the bioprocess. [less ▲]

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See detailModélisation du captage post-combustion du CO2 avec évaluation de la dégradation des solvants
Léonard, Grégoire ULg; BELLETANTE, Ségolène; Cabeza Mogador, Bruno et al

in Récents Progrès en Génie des Procédés (2013), 104

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy ... [more ▼]

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy demand. CO2 is chemically absorbed in an amine solvent that can be regenerated at higher temperature, producing a pure CO2 stream. However, the large impact of this technology on the power plant efficiency and the environmental penalty are the main drawbacks for large-scale implementation. In this work, an innovative approach combining process modeling and evaluation of the environmental penalty due to amine degradation is presented. Based on experimental results, the kinetics of solvent oxidative and thermal degradation is estimated and included in the process model developed in Aspen Plus. Using this model, the influence of operating parameters like the oxygen concentration in the flue gas or the solvent regeneration pressure is studied. This model is a first step for a multi-objective optimization of the CO2 capture process, assessing both energy and environmental penalties of this technology. [less ▲]

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See detailInvestigation of liquid flow morphology inside a structured packing using X-ray tomography
Janzen, Anna; Steube, Julia; Aferka, Saïd et al

in Chemical Engineering Science (2013), 12

In this work X-ray tomography is used to analyse the influence of liquid viscosity on liquid flow in a column filled with Mellapak Plus 752Y structured packing. Tomographic measurements are performed at ... [more ▼]

In this work X-ray tomography is used to analyse the influence of liquid viscosity on liquid flow in a column filled with Mellapak Plus 752Y structured packing. Tomographic measurements are performed at various column heights for different liquid flow rates. Water and glycerine aqueous solutions are successively used as working liquids in order to quantify the influence of liquid viscosity on hydrodynamic quantities such as liquid hold-up and gas-liquid interfacial area. As expected, both liquid hold-up and gas-liquid interfacial area increase with liquid flow rate. An increase of liquid viscosity has also a positive impact on liquid hold-up and on gas-liquid interfacial area. In all cases, the measured quantities are not constant along the bed height, leading to fluctuating axial profiles. Furthermore, tomographic images are used to identify different liquid flow patterns (films, contact-point liquid, flooded regions) in the irrigated cross section images. A method based on morphological techniques is proposed to quantify the fraction of liquid flow within each flow pattern depending on flow rate and liquid viscosity. [less ▲]

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See detailInvestigation of the influence of packing geometry and of liquid viscosity on the liquid flow morphology by using X-ray tomography
Janzen, Anna; Steube, Julia; Kenig, Evgeny et al

in Proceedings of the 7th World Congress on Industrial Process Tomography (2013)

X-ray tomography is used to investigate the influence of packing geometry and of liquid viscosity on hydrodynamic quantities, as well as on the liquid flow morphology inside a packed column successively ... [more ▼]

X-ray tomography is used to investigate the influence of packing geometry and of liquid viscosity on hydrodynamic quantities, as well as on the liquid flow morphology inside a packed column successively filled with two structured metallic packing, M752Y and M500X. As expected, liquid holdup and gas-liquid interfacial area increase with liquid flow rate and viscosity. In both packings, the film flow pattern predominates, while flooded regions remain minority. The influence of liquid flow rate and viscosity on flow morphology depends on the packing geometry. In M752Y, film and flooded region flows are clearly influenced, whereas in M500X, they are not. [less ▲]

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See detailMesure par tomographie à rayons X de l’influence de la viscosité du liquide sur la morphologie de l’écoulement dans un garnissage structuré
Janzen, Anna; Steube, Julia; Kenig, Evgeny et al

in Récents Progrès en Génie des Procédés (2013), 104

In this work X-ray tomography is used to analyse the influence of liquid viscosity on the local morphology of liquid flow in a column filled with Mellapak Plus 752Y structured packing. Water and glycerine ... [more ▼]

In this work X-ray tomography is used to analyse the influence of liquid viscosity on the local morphology of liquid flow in a column filled with Mellapak Plus 752Y structured packing. Water and glycerine aqueous solutions of various viscosities (1 to 20 cP) are successively used as working liquids. On tomographic images, three different local liquid flow patterns (films, contact-point liquid, flooded regions) may be identified. An image analysis method based on morphological techniques is developed to quantify the fraction of liquid flow within each flow pattern depending on flow rate and liquid viscosity. [less ▲]

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See detailEpuration catalytique de biogaz
Claude, Vincent ULg; Toye, Dominique ULg; Heinrichs, Benoît ULg et al

Poster (2012, November 08)

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See detailCO2 CAPTURE in POWER PLANTS: Process Simulation and Solvent Degradation
Léonard, Grégoire ULg; Lepaumier, Hélène; Thielens, Marie-Laure et al

Poster (2012, November)

Presentation of the research themes studied at the University of Liège in the field of CO2 capture

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See detailImplementation of structured metal packing for the design of biofilm reactor : analysis by high energy X-ray tomography and application to the production of lipopeptides by Bacillus subtilis
Zune, Quentin ULg; Soyeurt, Delphine; Ongena, Marc ULg et al

Poster (2012, October 08)

1. Whereas multi-species biofilm reactors are commonly used for treatments of water and gas effluents, new strategies are arising for the development of mono-species biofilm reactors in order to produce ... [more ▼]

1. Whereas multi-species biofilm reactors are commonly used for treatments of water and gas effluents, new strategies are arising for the development of mono-species biofilm reactors in order to produce high added value molecules. Thus, it is required to design new bioreactors able to promote the growth of the biomass on the form of a biofilm and to identify the key physico-chemical parameters involved in order to optimize the bioprocess. 2. Aim of this study was to investigate a pilot-scale biofilm reactor comprising a metal structured packing promoting growth of Bacillus subtilis as a biofilm for the production of lipopeptides, high added value compounds with high surface active properties. 3. In this work, the mechanical stirring system of a 20L stirred tank bioreactor has been removed and replaced by a metal structured packing positioned in the headspace of the vessel above a liquid phase. The culture medium is continuously recirculated on the packing thanks to a peristaltic pump and air supply is performed just above the liquid phase under the packing. High energy X-ray tomography was used to estimate non-invasively the biofilm distribution inside the packing and permitted to define parameters that affect scale-up. Performances of the biofilm reactor were compared with a submerged culture in a stirred tank reactor in terms of lipopeptides production. 4. After 72 hours of fermentation, 94 % of the total biomass adheres onto the metal packing on the form of a biofilm. The colonization of this latter has been visualized non-invasively by X-ray tomography directly inside the packing and shows a conical repartition of the biofilm mass (about 25% of the total volume of the packing) as well as the presence of clogging. However, unlike the submerged culture, no foam formation appeared during fermentation and surfactin yield reaches 345,4 ± 32,8 mg / L for the biofilm reactor against 277,3 ± 34,4 mg / L in the stirred tank reactor. 5. In conclusion, this experimental setting leads to a major technological progress avoiding foam formation and increasing surfactin production. Nevertheless, significant improvements are required at the level of the biofilm distribution in thin layers inside the packing in order to increase mass transfer and lipopeptides recoveries. Further investigations will be devoted to the optimization of the physico-chemical parameters involved in biofilm distribution. [less ▲]

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See detailImplementation of structured metal packing for the design of biofilm reactor : analysis by high energy X-ray tomography and application to the production of lipopeptides by Bacillus subtilis
Zune, Quentin; Soyeurt, Delphine; Ongena, Marc ULg et al

Poster (2012, October 08)

1. Whereas multi-species biofilm reactors are commonly used for treatments of water and gas effluents, new strategies are arising for the development of mono-species biofilm reactors in order to produce ... [more ▼]

1. Whereas multi-species biofilm reactors are commonly used for treatments of water and gas effluents, new strategies are arising for the development of mono-species biofilm reactors in order to produce high added value molecules. Thus, it is required to design new bioreactors able to promote the growth of the biomass on the form of a biofilm and to identify the key physico-chemical parameters involved in order to optimize the bioprocess. 2. Aim of this study was to investigate a pilot-scale biofilm reactor comprising a metal structured packing promoting growth of Bacillus subtilis as a biofilm for the production of lipopeptides, high added value compounds with high surface active properties. 3. In this work, the mechanical stirring system of a 20L stirred tank bioreactor has been removed and replaced by a metal structured packing positioned in the headspace of the vessel above a liquid phase. The culture medium is continuously recirculated on the packing thanks to a peristaltic pump and air supply is performed just above the liquid phase under the packing. High energy X-ray tomography was used to estimate non-invasively the biofilm distribution inside the packing and permitted to define parameters that affect scale-up. Performances of the biofilm reactor were compared with a submerged culture in a stirred tank reactor in terms of lipopeptides production. 4. After 72 hours of fermentation, 94 % of the total biomass adheres onto the metal packing on the form of a biofilm. The colonization of this latter has been visualized non-invasively by X-ray tomography directly inside the packing and shows a conical repartition of the biofilm mass (about 25% of the total volume of the packing) as well as the presence of clogging. However, unlike the submerged culture, no foam formation appeared during fermentation and surfactin yield reaches 345,4 ± 32,8 mg / L for the biofilm reactor against 277,3 ± 34,4 mg / L in the stirred tank reactor. 5. In conclusion, this experimental setting leads to a major technological progress avoiding foam formation and increasing surfactin production. Nevertheless, significant improvements are required at the level of the biofilm distribution in thin layers inside the packing in order to increase mass transfer and lipopeptides recoveries. Further investigations will be devoted to the optimization of the physico-chemical parameters involved in biofilm distribution. [less ▲]

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See detailDevelopment of optical trajectography device for the lagangian study of turbulent flow inside a stirred tank used in pharmaceutical industry
Collignon, Marie-Laure ULg; Delafosse, Angélique ULg; Delvigne, Frank ULg et al

Poster (2012, September 10)

Stirred tanks are devices that are widely used in various process steps of the pharmaceutical industry. The performance of these processes (animal cell culture, crystallization, flocculation …) strongly ... [more ▼]

Stirred tanks are devices that are widely used in various process steps of the pharmaceutical industry. The performance of these processes (animal cell culture, crystallization, flocculation …) strongly depend on the physico-chemical and hydrodynamic environment present locally in these tanks. To fully describe this local environment, an Eulerian - Lagrangian approach must be adopted in order to establish history of conditions met by a particle as a cell, a crystal or a floc. This approach implies to determine the trajectory followed by the particle. To this aim, the Chemical Laboratory of Liege University has developed a prototype of optical trajectography device. The objective of this paper is to present the device, developments that were necessary for its use and the results obtained. The device is composed of two cameras modeled by a pinhole model which record the position of a bead that has a size equal to 490 µm and that perfectly follows local flow structures. The measured trajectory has been validated by comparing average time velocity fields deduced from it to those measured, in the same operating conditions, by particle image velocimetry (P.I.V.). [less ▲]

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See detailDevelopment of a biomechanical model of deer antler cancellous bone based on X-ray microtomographic images
de Bien, Charlotte ULg; Mengoni, Marlène ULg; D'Otreppe, Vinciane ULg et al

in Micro-CT User Meeting 2012 - Abstract Book (2012, April)

Finite element models accurately compute the mechanical response of bone and bone-like materials when the models include their detailed microstructure. The aim of this paper is to develop and validate a ... [more ▼]

Finite element models accurately compute the mechanical response of bone and bone-like materials when the models include their detailed microstructure. The aim of this paper is to develop and validate a biomechanical model for deer antler cancellous bone tissue based on X-ray microtomographic images. In order to simulate the mechanical behavior under compressive load using a finite element model, images obtained by X-ray microtomography were exported into Metafor, which is an non-linear finite element software initially developed at University of Liège for metal forming processes. This software has recently found biomedical applications. The ultimate goal is to compare model predictions with the mechanical behavior observed experimentally using the Skyscan material testing stage under compression mode. The creation of the biomechanical model mesh from segmented μCT images, its integration into the software Metafor and the simulation of a compression test are described in this paper. [less ▲]

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See detailMicrostructure characterisation of nanocomposite polymeric foams by X-ray microtomography
Plougonven, Erwan ULg; Detrembleur, Christophe ULg; Tran, Minh Phuong ULg et al

Poster (2012, March 26)

Recent advances in microstructured materials have given rise to many new types of composites that exhibit original and interesting physical properties. For example, a nanocomposite made of carbon ... [more ▼]

Recent advances in microstructured materials have given rise to many new types of composites that exhibit original and interesting physical properties. For example, a nanocomposite made of carbon nanotubes inside a polymer matrix shows exceptional electromagnetic interference shielding effectiveness when foamed. However, the effective properties of such materials strongly depend on the shape and topology of the microstructural cells. An accurate method for investigating the cellular microstructure is X-ray microtomography (XRμT), for it is non-destructive, and it provides 3D geometric information. Although it cannot be used to observe nanofiller dispersion, it has a strong potential for cell structure characterisation. In order to reduce the need for trial and error in tailoring these materials, our objective is to quantify, using XRμT, cellular microstructure, for two different types of foaming procedures, namely supercritical CO2 batch foaming and freeze drying, to be able to establish a link between the structure and its shielding effectiveness. The main difficulty stems from the type of material being studied: it is light, therefore hardly absorbs X-rays, cell size is small compared to the resolution capacity of the tomograph, and cell wall thickness is extremely thin in some cases, making them very hard to discern in the images. For these reasons, common image analysis tools for identifying and delimiting objects in an image prove impractical. We propose an original method that uses the 3D autocorrelation function of the tomograms to determine statistical information from these images, such as average cell size and anisotropy, without the need to binarise and segment the images. [less ▲]

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See detailModellierung des Trennverhaltens wässriger Systeme in Packungskolonnen basierend auf tomographischen
Janzen, Anna; Steube, Julia; Aferka, Saïd ULg et al

Conference (2012, March)

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See detailDesign of a biofilm reactor comprising a metal structured packing for the production of lipopeptides by B. subtilis
Zune, Quentin ULg; Ongena, Marc ULg; Toye, Dominique ULg et al

Poster (2012, February 08)

Abstract : The design of a new single species biofilm bioreactor has been investigated. Bacillus subtilis S499 has been chosen as a model organism for the production of lipopetides. Nevertheless ... [more ▼]

Abstract : The design of a new single species biofilm bioreactor has been investigated. Bacillus subtilis S499 has been chosen as a model organism for the production of lipopetides. Nevertheless, considering the surface active properties for this kind of metabolite, processes based on submerged culture in stirred-tank bioreactor involve the use of important amount of antifoam and therefore downstream processes are tedious. In this work, an original process was developed with an experimental setting leading to the suppression of foam formation during the culture. B. subtilis S499 makes a biofilm on a stainless steel structured packing in the top of a bioreactor, nutrient and oxygen supply being carried out by the media recirculation as liquid film on the packing. Lipopeptides secreted by biofilm are accumulated in the liquid phase under the packing and can reach concentrations as high as 800 mg/l. The colonization of the packing by the biofilm has been monitored by X-ray tomography. [less ▲]

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See detailA non-linear homogeneous model for bone-like materials under compressive load.
Mengoni, Marlène ULg; Voide, Romain; de Bien, Charlotte ULg et al

in International Journal for Numerical Methods in Biomedical Engineering (2012), 28(2), 334-348

Finite element (FE) models accurately compute the mechanical response of bone and bone-like materials when the models include their detailed microstructure. In order to simulate non-linear behavior, which ... [more ▼]

Finite element (FE) models accurately compute the mechanical response of bone and bone-like materials when the models include their detailed microstructure. In order to simulate non-linear behavior, which currently is only feasible at the expense of extremely high computational costs, coarser models can be used if the local morphology has been linked to the apparent mechanical behavior. The aim of this paper is to implement and validate such a constitutive law. This law is able to capture the non-linear structural behavior of bone-like materials through the use of fabric tensors. It also allows for irreversible strains using an elastoplastic material model incorporating hardening. These features are expressed in a constitutive law based on the anisotropic continuum damage theory coupled with isotropic elastoplasticity in a finite strains framework. This material model was implemented into Metafor, a non-linear FE software. The implementation was validated against experimental data of cylindrical samples subjected to compression. Three materials with bone-like microstructure were tested : aluminum foams of variable density (ERG, Oakland, CA), PLA (polylactic acid) foam (CERM, University of Liège) and cancellous bone tissue of a deer antler (Faculty of Veterinary Medicine, University of Liège). [less ▲]

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See detailPOST-COMBUSTION CO2 CAPTURE: Global Process Simulation and Solvent Degradation
Léonard, Grégoire ULg; Lepaumier, Hélène; Blandina, Fabrice et al

Poster (2012, February)

One of the biggest upcoming challenges concerning both environmental and energy systems engineering is the control and limitation of greenhouse gas emissions due to human activity. Fossil fuels-fired ... [more ▼]

One of the biggest upcoming challenges concerning both environmental and energy systems engineering is the control and limitation of greenhouse gas emissions due to human activity. Fossil fuels-fired power plants are in this context one of the main contributors due to the large amounts of CO2 emitted. Different technologies have been developed for capturing CO2 from such power plants. This work focuses on post-combustion CO2 capture by reactive absorption into amine solvents like monoethanolamine (MEA). The main drawback of this technology is actually the high energy requirement of the process, especially for solvent regeneration. It is then highly interesting to model the capture process so that optimal operating conditions could be approached by simulation thus reducing the number of expensive experimental tests. Thanks to the simulation, it has been possible to identify the most influent process variables and to optimize their value. It was also possible to study the impact of process modifications on the global capture efficiency. The improvements studied allowed for a reduction by up to 14% of the process exergy consumption. Another major drawback of the post-combustion CO2 capture is solvent degradation, which can be due to thermal as well as oxidative mechanisms. Degradation affects the CO2 capture process since it may cause corrosion, foaming and fouling, possibly inducing a decrease of the solvent efficiency and high additional operating costs due to solvent replacement. In order to study degradation of conventional amine solvents as well as degradation of novel solvents, a degradation test rig has been built at the University of Liège in collaboration with the company Laborelec, member of the GDF SUEZ group. First results show that degradation obtained on this lab installation can be compared to degradation results observed on CO2 capture pilot installation. The final objective of this thesis is to make a link between degradation and simulation. Experimental data obtained on the degradation test rig will be implemented into the existing simulation model so that optimal operating conditions considering both process energy efficiency and solvent degradation can be determined. [less ▲]

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See detailStudy of 2-Ethanolamine degradation
Léonard, Grégoire ULg; Toye, Dominique ULg; Heyen, Georges ULg

Conference (2012, January)

One major drawback of the post-combustion CO2 capture using conventional amine solvents is solvent degradation, which can be due to thermal as well as oxidative mechanisms. Degradation affects the CO2 ... [more ▼]

One major drawback of the post-combustion CO2 capture using conventional amine solvents is solvent degradation, which can be due to thermal as well as oxidative mechanisms. Degradation affects the CO2 capture process since it may cause corrosion, foaming and fouling, possibly inducing a decrease of the solvent efficiency and high additional operating costs due to solvent replacement. In order to study degradation of conventional amine solvents as well as degradation of novel solvents, a degradation test rig has been built at the University of Liège in collaboration with the company Laborelec, member of the GDF SUEZ group. Since degradation generally occurs within a few months in real plant conditions, this equipment has been designed to allow the study of different degradation mechanisms under accelerated conditions, at high temperatures (up to 140°C) and high partial pressures in oxygen and CO2 (total pressure up to 20 bar with varying gas composition). An advantage of this degradation test rig is that it can be used in batch as well as in semi-batch mode with constant gas flow. High gas-liquid contact efficiency is also ensured thanks to a mechanical agitation system combined with gas bubbling. For a typical run, 300g of aqueous amine solution (30 wt % MEA in water) is introduced into the reactor and degraded during two weeks. The degraded solutions are then analysed using high pressure liquid chromatography (HPLC) for MEA quantification and gas chromatography with flame ionization detector (GC-FID) for the characterization of degradation products. The gas phase is analysed by Fourier Transform Infra Red spectroscopy. The final objective of this work is to implement the data obtained from experimental results on the degradation test rig into an existing simulation model that has been developed based on an existing pilot plant. [less ▲]

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See detailInvestigation of liquid flow pattern inside a structured packing using X-ray tomography
Aferka, Saïd ULg; Steube, Julia; Janzen, Anna et al

in Proceedings of the 6th International Symposium on Process Tomography, Cape Town, South Africa (2012)

This work focuses on the analysis of X-ray tomographic images of liquid flow distribution within a 1 m high packed column of 10 cm diameter, filled with four Mellapak Plus 752Y elements. Tomographic ... [more ▼]

This work focuses on the analysis of X-ray tomographic images of liquid flow distribution within a 1 m high packed column of 10 cm diameter, filled with four Mellapak Plus 752Y elements. Tomographic measurements are performed at various column heights for different liquid flowrates. Water and aqueous glycerine solutions are successively used as working liquids in order to quantify the influence of liquid viscosity on the spatial distribution of hydrodynamic quantities such as liquid holdup and gas-liquid interfacial area. Logically, both liquid holdup and gas-liquid interfacial area increase with liquid flow rate. An increase of liquid viscosity has also a positive impact on liquid holdup and on gas-liquid interfacial area. In all cases, the measured quantities are not constant along the bed height, leading to fluctuating axial profiles. Depending on the liquid viscosity and flowrate, different liquid flow patterns (films, rivulets, flooded channels) are observed in the irrigated cross section images. A method based on morphological techniques is proposed to quantify the fraction of liquid flow which belongs to each flow pattern. [less ▲]

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See detailFormation à la microtomographie
Léonard, Angélique ULg; Toye, Dominique ULg; Plougonven, Erwan ULg

Learning material (2011)

This course is a two-day presentation of the basic workings of X-ray tomography, current local applications of microtomography in the applied chemistry department, typical image analysis tools for ... [more ▼]

This course is a two-day presentation of the basic workings of X-ray tomography, current local applications of microtomography in the applied chemistry department, typical image analysis tools for extracting measurements, and a practical look at a particular piece of equipment, the Skyscan 1172 desktop microtomograph, and its software. The target audience is users of such equipment, with little to no background in X-ray physics, computer science or image analysis. [less ▲]

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