References of "Léonard, Angélique"
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See detailInvestigation on Convective Drying of Mixtures of Sewage Sludge and Sawdust in a Fixed Bed
Li, Jie ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

in Drying Technology (2015), 33(6), 704-712

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See detailOn Water Transfer and Hydraulic Connection Layer During the Convective Drying of Rigid Porous Material
Prime, Noémie; Housni, Z; Fraikin, Laurent ULg et al

in Transport in Porous Media (2015), 106(1), 47-72

The convective drying of a natural porous material, limestone, is investigated in this study, with both experimental and numerical approaches. The first experimental campaign, which focuses on the ... [more ▼]

The convective drying of a natural porous material, limestone, is investigated in this study, with both experimental and numerical approaches. The first experimental campaign, which focuses on the influence of samples’ slenderness, suggests the presence of a hydraulic connection layer between the porous water and the external environment, in spite of the very fine pore structure of the material. This hydraulic transfer enables the fast water evaporation at the beginning of the drying test, when external conditions drive the kinetics. Furthermore, the results show that this layer does not exceed 30 mm deep from the external surface, given the drying conditions of the test. A second experimental campaign aims to analyse, by mean of an X-ray tomography tool, the internal water content during the drying. It confirms that water transfer takes place within the limestone in two distinct stages. The first stage being faster than the second one with a homogeneous desaturation along the sample, it is consistent with the hypothesis of the hydraulic connection layer. Finally, the finite element modelling makes possible to identify the main mechanisms of water transfer, namely liquid convection and vapour diffusion. © 2014, Springer Science+Business Media Dordrecht [less ▲]

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See detailImage analysis of X-ray tomograms of sludge during convective drying in a pilot-scale fixed bed
Li, Jie ULg; Plougonven, Erwan ULg; Fraikin, Laurent ULg et al

in Chemical Engineering Science (2015), 134

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See detailConvective drying of a single cherry tomato: Modeling and experimental study
Bennamoun, Lyes; Khama, Reda; Léonard, Angélique ULg

in Food and Bioproducts Processing (2015), 94

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See detailEnvironmental relevance of end of life vehicle valorisation - LCA of COMET case study
Groslambert, Sylvie ULg; Belboom, Sandra ULg; Lewis, Grégory et al

Conference (2014, November 17)

LCA of Electric Vehicles Recycling : Comparison between three business lines of dismantling

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See detailEnhanced sludge dewatering and drying comparison of two linear polyelectrolytes co-conditioning with Polyaluminium chloride
Pambou, Yvon-Bert ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

Poster (2014, October 23)

Annual production of sewage sludge in Europe is estimated at more than ten million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge drying ... [more ▼]

Annual production of sewage sludge in Europe is estimated at more than ten million tons of dry matter. Use in agriculture and incineration are the main ways of valorization. In this context, sludge drying appears as an essential step after mechanical dewatering. It reduces the costs of storage and transport, allows the stabilization and the hygienization of sludge while increasing its calorific value. However, this process is highly energy consuming and still needs to be optimized as it constitutes an important economic and environmental issue. This implies the improvement of knowledge about sludge drying, including the impact of the mechanical dewatering step. Before studying experimentally the influence of polymers type and dosage use for dewatering on the rheological properties and the drying process, it is necessary to assess the stability of the sludge during of the storage. Because sludge is a living material that can rapidly change, we use the method of experimental design in order to get maximum information with minimal testing, regarding sludge stability during storage. [less ▲]

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See detailINFLUENCE OF SLUDGE TREATEMENT ON ITS CONVECTIVE DRYING BEHAVIOR
Fraikin, Laurent ULg; Herbreteau, Benjamin; Salmon, Thierry ULg et al

Conference (2014, August 27)

Drying appears as a major step prior to valorization of sludge from wastewater treatment plant. This study uses an experimental design on different sludges to highlight the drying behavior according to ... [more ▼]

Drying appears as a major step prior to valorization of sludge from wastewater treatment plant. This study uses an experimental design on different sludges to highlight the drying behavior according to drying conditions, storage and extrusion. This research is performed with industrial view, but on a single cylinder sample, and focuses on five responds: maximum drying flux, time to reach 95% of dry matter, final volume, critical moisture and slowing-down coefficient. [less ▲]

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See detailmodelling heat and mass transfer during convective drying of a building material
Kahlerras, Loubna ULg; Belhamri, Azeddine; Fraikin, Laurent ULg et al

Poster (2014, August 24)

The purpose of this study is to characterize experimentally the behaviour of a cement mortar during its convective drying. The work presented here focuses on mortars with water-to cement ratios (w/C) of 0 ... [more ▼]

The purpose of this study is to characterize experimentally the behaviour of a cement mortar during its convective drying. The work presented here focuses on mortars with water-to cement ratios (w/C) of 0, 5. The drying tests are realized in a convective dryer designed for the drying of small samples (0 - 8g). Experiences are realized with different conditions of drying air temperature (60, 90 and 130 °C) and velocity (2, 3 and 5 m/s) the results show the influence of temperature and velocity on drying curve. Mathematical models have been used for the description of drying curves. The exponential mathematical model seems the most adequate to describe the drying curves of cement mortars, with correlation coefficients changing with the air temperature and velocity and close to unity. The convective mass and heat transfer coefficients are determined from the experimental data. The results showed that both mass and heat transfer coefficients were affected by the air temperature and velocity. The convective mass transfer coefficient changed from 0.0232m/s at V=2m/s to 0.045m/s at V=5m/s, and from 0.055 m/s at 60°c to 0.023 at 130°c. Heat transfer coefficient changed from 14.767 w/m2°c at V=2m/s to 28.64 w/m2°c at V=5m/s and from 7.71 at 60° c to 14.77 at 130°c The temperature dependency of the two coefficients was expressed using an Arrhenius-type equation and related parameters were deduced [less ▲]

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See detailExperimental study of the drying kinetic of mortar
Kahlerras, Loubna ULg; Michel, Frédéric ULg; Courard, Luc ULg et al

Poster (2014, August 24)

This work reports the results of an experimental study concerning on one hand the influence of water-to cement ratios (W/C), and the role of aggregates on the other hand on the drying kinetics of cement ... [more ▼]

This work reports the results of an experimental study concerning on one hand the influence of water-to cement ratios (W/C), and the role of aggregates on the other hand on the drying kinetics of cement pastes during thermal drying. Three types of cement pastes were realized and studied; cement pastes with ratios W/C 0.4, W/C 0.5 and mortar with ratio W/C 0.5. These tries present the advantage to reproduce the natural conditions met in the problems of interaction atmosphere and material. Cylindrical samples of cement of size (17 X 13) mm are dried in a convective dryer. The sample is continuously weighed during the drying test and its mass is recorded every 60 s, in the purpose to obtain the drying curves. The results show that the increase of the W/C ratio leads to an increase of the drying rate due to the increase of the initial porosity. The effect of the introduction of aggregates is observable by the comparison of the drying curve obtained for the mortar and the cement pastes. The results show a decrease of the drying kinetics with mortars. The results also show that the air drying temperature has a large impact on the drying process, increasing the temperature leading to significant drying time reduction. The Effective diffusion coefficient is calculated by comparison between the experimental results and the analytical solution of Fick’s equation written for a finite medium. [less ▲]

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See detailIMPACT OF A HIGH LINEAR WEIGHT POLYMER CO-CONDITIONING WITH POLYALUMINIUM CHLORIDE ON DEWATERING AND CONVECTIVE DRYING OF URBAN RESIDUAL SLUDGE
Pambou, Yvon-Bert ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

Poster (2014, August)

This paper investigated the influence of Polyaluminium chloride (PAX) co-conditioning with a high linear weight polymer on the dewatering performance and the drying behavior of sludge. The CT linear ... [more ▼]

This paper investigated the influence of Polyaluminium chloride (PAX) co-conditioning with a high linear weight polymer on the dewatering performance and the drying behavior of sludge. The CT linear polymer with a high molecular weight was used combined with PAX for sludge flocculation prior to mechanical dewatering and drying. It was found that sludge conditioned with the couple PAX/ CT led to better flocculation/dewatering process regarding size flocs and specific resistance to filtration. Concerning drying, it appeared that this chemicals combination led to improved drying rates with effect of a reduction of the drying time, when compared to polyelectrolyte used without PAX adding. [less ▲]

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See detailModeling of a glass mineral wool process in view of Life Cycle Analysis
Gerbinet, Saïcha ULg; Briard, Vincent; Léonard, Angélique ULg

in Matériaux et Techniques (2014), 102(502),

In line with the growing concern about the environmental impact of materials in the building sector, Knauf Insulation, a glass wool producer, is performing environmental impact assessment of its products ... [more ▼]

In line with the growing concern about the environmental impact of materials in the building sector, Knauf Insulation, a glass wool producer, is performing environmental impact assessment of its products through LCA. Knauf Insulation has several glass wool factories in Europe that produce various products, and for a specific market, the same product can be produced in several factories. As the plants that produce glass wool work with similar pathways, a generic model for LCA usable for every plant and every glass wool product has been designed. The general principle of glass wool production is the following: the raw materials, sand, limestone, soda ash, borax, sodium carbonate, as well as recycled off-cuts from the production process, are weighed and mixed. Knauf Insulation also uses a large amount of recycled glass (cullet). The mix is sent to a furnace at high temperature (1350°C). The melted material is then fiberized and the binder is added, a process called forming. Knauf Insulation uses a special binder with ECOSE Technology, a new and formaldehyde-free binder. The wool fibers are collected, by suction, on a conveyor belt, and the mattress then goes through the curing oven. For some products a facing is added. Finally the product is compressed and packed. Specific attention is put in certain LCA aspects, such as allocations procedures, and we have used ISO 14040 and 14044 along with the ILCD handbook as guides during the model development. LCA is performed from raw materials extraction to end-of-life. Nevertheless, the impacts of the insulation system use phase are not included, as they strongly depend on parameters such as construction systems, etc. The functional unit is defined as 1 m3 of specific glass mineral wool product. The model, implemented in GaBi 6, is made as generic as possible by including, for each step, all the raw materials that can be used in one of the factories as well as all the energy sources. Parameters allow to define the amount of each raw material consumed, therefore the model can be adapted to any factory simply by setting these parameters accordingly. Moreover, the transport distances are also parameters and the origin of the energies (electricity or heat) can also be selected. This simplifies the data collection, since the template is the same for all the factories, it can be supported by data collection tools already existing. A part of the model is dedicated to weighting between factories, so a combination of factories can also be studied. This allows to study products sold on a specific market. The model can also be adapted to almost all Knauf Insulation products by using parameters where necessary: for example, several products have different binder contents, so a parameter defines the amount of binder. As some materials can be recycled between several parts of the process, special attention has been paid to recycling loops inside the model. The model is flexible enough to be used for Environmental Product Declaration (EPD) as well as for Eco-Design purposes. [less ▲]

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See detailEnhanced sludge dewatering and drying comparison of two linear polyelectrolytes co-conditioning with Polyaluminium chloride
Pambou, Yvon-Bert ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

Poster (2014, May 26)

Annual production of sewage sludge in Europe is estimated at more than eleven million tons of dry matter content [1]. Use in agriculture and incineration are the main ways of valorization. In this context ... [more ▼]

Annual production of sewage sludge in Europe is estimated at more than eleven million tons of dry matter content [1]. Use in agriculture and incineration are the main ways of valorization. In this context, drying of residual sludge appears as an essential step after mechanical dewatering. It reduces the costs of storage, transport and allows the sludge stabilization. However, this process is highly energy consuming and still needs to be optimized as it constitutes an important economic and environmental issue [2]. Polymers are usually employed in the conditioning step in order to promote particle aggregation, making the dewatering easier. The past decades, the application of pre-hydrolized polyaluminium chlorides (PACls) as coagulant has increased, particularly in China, Japan, Russia and Western Europe [3]. As a consequence, PACls are extensively investigated for their coagulation performance, characterization and speciation [3]. In this work, the influence of Polyaluminium chloride (PAX-14) co-conditioning with linear polyelectrolytes on sludge dewatering and drying performances was investigated. Experiments were conducted on activated sludge samples collected after thickening from the wastewater treatment plant of the Grosses- Battes (Belgium). Two cationic polymers were tested, each of them in combination with PAX for sludge flocculation prior to mechanical dewatering and their effects on sludge convective drying. The one referenced as 640 LH was a linear polymer with a low molecular weight, whereas the 640 CT was a linear one with a high molecular weight. After conditioning, the dewatering step was realized by using a normalized filtration-expression cell (AFNOR 1979) under 5 bar of pressure. Then, the specific resistance to filtration was determined from the follow-up of filtrate mass with time, using the Carman-Kozeny equation [4]. Figure 1 shows the experimental design. For convective drying experiments, the cake recovered after filtration was extruded through a circular die of 14 mm diameter and cut at a height of 14 mm, yielding cylindrical samples with mass of approximately 2.5 g, as used in several industrial belt dryers. Individual extrudates have been dried in a specially designed convective micro-dryer. Results reported in this paper were obtained with the following operating conditions: air temperature of 130 °C, at ambient humidity (absolute humidity ~ 0.005 kgwater/ kgdry air) and a superficial velocity of 1 m/ s. Results show that, the dry solids content of the dewatering cake increases with increasing Polyaluminium chloride dosage for both series of experiments. It supposes that PAX contributed to improve solids capture, depicted on Fig. 2. Concerning drying, it appeared that the samples treated by the dual PAX/ polymers combination showed higher drying rates than samples conditioned by polymer without PAX addition, allowing a reduction of the drying time (see Fig. 3). Table 1 shows the drying characteristics of the samples. The drying time decreases and the average drying rate increases with the dual conditioners addition, while the initial water content decreases as well as the total amount water to be removed. [less ▲]

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See detailModeling of a glass mineral wool process in view of Life Cycle Analysis
Gerbinet, Saïcha ULg; Léonard, Angélique ULg; Briard, Vincent

Conference (2014, May 20)

In line with the growing concern about the environmental impact of materials in the building sector, Knauf Insulation, a glass wool producer, is performing environmental impact assessment of its products ... [more ▼]

In line with the growing concern about the environmental impact of materials in the building sector, Knauf Insulation, a glass wool producer, is performing environmental impact assessment of its products through LCA. Knauf Insulation has several glass wool factories in Europe that produce various products, and for a specific market, the same product can be produced in several factories. As the plants that produce glass wool work with similar pathways, a generic model for LCA usable for every plant and every glass wool product has been designed. The general principle of glass wool production is the following: the raw materials, sand, limestone, soda ash, borax, sodium carbonate, as well as recycled off-cuts from the production process, are weighed and mixed. Knauf Insulation also uses a large amount of recycled glass (cullet). The mix is sent to a furnace at high temperature (1350°C). The melted material is then fiberized and the binder is added, a process called forming. Knauf Insulation uses a special binder with ECOSE Technology, a new and formaldehyde-free binder. The wool fibers are collected, by suction, on a conveyor belt, and the mattress then goes through the curing oven. For some products a facing is added. Finally the product is compressed and packed. Specific attention is put in certain LCA aspects, such as allocations procedures, and we have used ISO 14040 and 14044 along with the ILCD handbook as guides dur-ing the model development. LCA is performed from raw materials extraction to end-of-life. Nevertheless, the impacts of the insulation system use phase are not included, as they strongly depend on parameters such as construction systems, etc. The functional unit is defined as 1 m3 of specific glass mineral wool product. The model, implemented in GaBi 6, is made as generic as possible by including, for each step, all the raw materials that can be used in one of the factories as well as all the energy sources. Parameters allow to define the amount of each raw material consumed, therefore the model can be adapted to any factory simply by setting these parameters accordingly. Moreover, the transport distances are also parameters and the origin of the energies (electricity or heat) can also be selected. This simplifies the data collection, since the template is the same for all the factories, it can be supported by data collection tools already existing. A part of the model is dedicated to weighting between factories, so a combination of factories can also be studied. This allows to study products sold on a specific market. The model can also be adapted to almost all Knauf Insulation products by using parameters where necessary: for example, several products have different binder contents, so a parameter defines the amount of binder. As some materials can be recycled between several parts of the process, special attention has been paid to recycling loops inside the model. The model is flexible enough to be used for Environmental Product Declaration (EPD) as well as for Eco-Design purposes. [less ▲]

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See detailModeling of a glass mineral wool process in view of Life Cycle Analysis
Gerbinet, Saïcha ULg; Léonard, Angélique ULg; Briard, Vincent

Poster (2014, May 12)

In line with the growing concern about the environmental impact of materials in the building sector, Knauf Insulation, a glass wool producer, is performing environmental impact assessment of its products ... [more ▼]

In line with the growing concern about the environmental impact of materials in the building sector, Knauf Insulation, a glass wool producer, is performing environmental impact assessment of its products through LCA. Knauf Insulation has several glass wool factories in Europe that produce various products, and for a specific market, the same product can be produced in several factories. As the plants that produce glass wool work with similar pathways, a generic model for LCA usable for every plant and every glass wool product has been designed. Moreover, combination of different factories is also possible. The general principle of glass wool production is the following: the raw materials, sand, limestone, soda ash, borax, sodium carbonate, as well as recycled off-cuts from the production process, are weighed and mixed. Knauf Insulation also uses a large amount of recycled glass (cullet). The mix is sent to a furnace at high temperature (1350°C). The melted material is then fiberized and the binder is added, a process called forming. Knauf Insulation uses a special binder with ECOSE Technology, a new and formaldehyde-free binder. The wool fibers are collected, by suction, on a conveyor belt, and the mattress then goes through the curing oven. For some product a facing is added. Finally the product is compressed and packed. The model, implemented in GaBi 6, is made as generic as possible by including, for each step, all the raw materials that can be used in one of the factories as well as all the energy sources. Parameters allow to define the amount of each raw material consumed, therefore the model can be adapted to any factory simply by setting these parameters accordingly. This also simplifies the data collection, since the template is the same for all the factories, it can be supported by data collection tools already existing. A part of the model is dedicated to weighting between factories, so a combination of factories can also be studied. The model can also be adapted to almost all Knauf Insulation products by using parameters where necessary: for example, several products have different binder contents, so a parameter defines the amount of binder. As some materials can be recycled between several parts of the process, special attention has been paid to recycling loops inside the model. The model is flexible enough to be used for Environmental Product Declaration (EPD) as well as for Eco-Design purposes. [less ▲]

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See detailDetermination of the environmental footprint of the anthropic water cycle using LCA
Groslambert, Sylvie ULg; Léonard, Angélique ULg

Poster (2014, May)

The aim of this study is to describe the development of a life cycle assessment of drinking water in the Walloon Region, in Belgium. This study also includes rainwater harvesting as a complement to tap ... [more ▼]

The aim of this study is to describe the development of a life cycle assessment of drinking water in the Walloon Region, in Belgium. This study also includes rainwater harvesting as a complement to tap water. Data collected for this report are based on information available for 2010 as reference year. The functional unit is 1 m³ of water used by a Walloon citizen (including both rainwater and drinking water). [less ▲]

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See detailAnalysis of the Shrinkage Effect on Mass Transfer During Convective Drying of Sawdust/Sludge Mixtures
Li, Jie ULg; Bennamoun, Lyes; Fraikin, Laurent ULg et al

in Drying Technology (2014), 32

Convective drying of wastewater sludges and sawdust/sludge mixtures was studied. The first part of this work was an experimental study performed in a cross-flow convective dryer using 500 g of wet ... [more ▼]

Convective drying of wastewater sludges and sawdust/sludge mixtures was studied. The first part of this work was an experimental study performed in a cross-flow convective dryer using 500 g of wet material extruded through a disk with circular dies of 12 mm. The results showed that the sawdust addition has a positive impact on the drying process from a mass ratio of 2/8, on a dry basis, with observed drying rates higher than the original sludge. The second part of this work consisted of developing a drying model in order to identify the internal diffusion coefficient and convective mass transfer coefficient from the experimental data. A comparison was made between fitted drying curves, well represented by the Newton’s model, and the analytical solutions of the diffusion equation applied to a finite cylinder. Variations of dimensional characteristics such as the volume and exchange surface of the sample bed were obtained by X-ray tomography. This technique allowed confirm that shrinkage, which is an important phenomenon occurring during sludge and sawdust/mixture drying, must be taken into account. The results showed that both the internal diffusion coefficient and convective mass transfer coefficient were affected by mixing and sawdust addition. The internal diffusion coefficient changed from 7.77×10-9 m2/s for the original sludge to 7.01×10-9 m2/s for the mixed sludge and then increased to 8.35×10-9 m2/s for the mixture of a mass ratio of 4/6. The convective mass transfer coefficient changed from 9.70×10-8 m/s for the original sludge to 8.67×10-8 m/s for the mixed sludge and then increased to 12.09×10-8 m/s for the mixture of a mass ratio of 4/6. These results confirmed that sawdust addition was beneficial to the sludge drying process as the mass transfer efficiency between the air and material increased. Reinforcing the texture of sludge by adding sawdust can increase the drying rate and decrease the drying time, and then the heat energy supply will be reduced significantly. The study also showed that neglecting shrinkage phenomenon resulted in an overestimation for the internal diffusion coefficient for the convective drying of sludges and sawdust/sludge mixtures. [less ▲]

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See detailCoupling X-ray microtomography and macroscopic soil measurements: a method to enhance near saturation functions?
Beckers, Eléonore ULg; Plougonven, Erwan; Gigot, Nicolas et al

in Hydrology and Earth System Sciences (2014), 18

Agricultural management practices influence soil structure, but the characterization of these modifications and consequences are still not completely understood. In this study, we aim at improving water ... [more ▼]

Agricultural management practices influence soil structure, but the characterization of these modifications and consequences are still not completely understood. In this study, we aim at improving water retention and hydraulic conductivity curves using both classical soil techniques and X-ray microtomography in the context of tillage simplification. We show a good match for retention and conductivity functions between macroscopic measurements and microtomographic information. Microtomography highlights the presence of a secondary pore system. Analysis of structural parameters for these pores appears to be significant and offers additional clues for objects differentiation. We show that relatively fast scans supply not only good results, but also enhance near saturation characterization, making microtomography a highly competitive instrument for routine soil characterization. [less ▲]

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