26 research outputs found
Performances dâun filtre Ă manche pour la capture de particules en conditions reprĂ©sentatives de lâincinĂ©ration de nano-dĂ©chets
Filtration performance of a pulse-jet bag filter was evaluated at the laboratory-scale regarding submicronic particles with a nanosized fraction during clogging/unclogging cycles. The particle size distribution was representative to those encountered at the outlet of a nano-waste incineration device at laboratory-scale. The bag filter was operated in conditions as similar as possible to those found in flue gas treatment of waste incineration plants, in terms of temperature, humidity, filtration velocity, injection of sorbent reagents and unclogging conditions. The air flow and the bag filter were heated to 150°C, the water content was maintained in the air flow in the range of 10-12% (3% of relative humidity RH), and filtration velocity throughout the bag filter was fixed at 1.9 cm.sâ»Âč. A mixture of submicronic suspended particles of activated carbon and sodium bicarbonate, both used in flue gas treatment systems mainly for the removal of dioxins/furans and acid gases, was generated simultaneously with the aerosol representative of combustion emissions.The study focused on the filtration performance at the beginning of the bag filterâs lifetime filter for the 11 first clogging-unclogging cycles before stabilizing the residual pressure drop reached after pulse-jet unclogging. The maximum pressure drop was set at 150 Pa for all filtration cycles. Once the maximum pressure drop was reached, the filter was unclogged using the pulse-jet system. The performance of the bag filter was evaluated in terms of the evolution of pressure drop, fractional and total particle collection efficiencies, during the clogging/unclogging cycles.Moreover, an experimental and theoretical study was carried out on the influence of different parameters on the filtration performance of bag filter and flat filter, such as influence of humidity (3% RH versus 0% RH at 150°C), temperature (150°C versus 24°C), filtration velocity (1.9 cm.sâ»Âč versus 1.4 cm.sâ»Âč) and the influence of the injection of sorbent reagents.The main results of this study are: (i) high collection efficiency of the bag filter in representative conditions of flue gas treatment of waste incineration: minimun particle collection efficiency of 98.5% for particle diameter of 74 ± 15 nm (electrical mobility diameter), (ii) influence of residual particle cake at the beginning of the filtration cycles on the bag filter performance, (iii) significant influence of humidity on the porosity of the particle cake due to the capillary condensation of water between the particles in presence of humidity (150°C - 3% RH i.e. almost 100 g of water per kg of dry air). Faster increase of bag filter pressure drop in presence of humidiy (150°C - 3% RH) as compared to the dry conditions (150°C - 0% RH).Les performances de filtration dâun filtre Ă manche vis-Ă -vis de particules submicroniques et nanomĂ©triques ont Ă©tĂ© Ă©valuĂ©es Ă lâĂ©chelle du laboratoire durant plusieurs cycles de colmatage/dĂ©colmatage. La distribution granulomĂ©trique des particules (aĂ©rosol de combustion) Ă©tait reprĂ©sentative de celle rencontrĂ©e en incinĂ©ration de nano-dĂ©chets en sortie de chambre de combustion Ă lâĂ©chelle du laboratoire. Le filtre Ă manche opĂ©rait en conditions rĂ©alistes, reprĂ©sentatives de celles rencontrĂ©es dans les lignes de traitement des fumĂ©es dâincinĂ©ration de dĂ©chets en termes de tempĂ©rature, humiditĂ©, vitesse de filtration, prĂ©sence de rĂ©actifs et conditions de dĂ©colmatage. Le flux dâair et le filtre Ă manche Ă©taient chauffĂ©s Ă 150°C, la teneur en eau Ă©tait de 10-12% (soit 3% dâhumiditĂ© relative HR), et la vitesse de filtration Ă©tait fixĂ©e Ă 1,9 cm.sâ»Âč. Un mĂ©lange de particules de taille submicronique de charbon actif et de bicarbonate de sodium, utilisĂ©es dans les lignes de traitement des fumĂ©es dâincinĂ©ration pour lâabattement des dioxines/furanes et des gaz acides, Ă©tait gĂ©nĂ©rĂ© simultanĂ©ment avec lâaĂ©rosol de combustion. LâĂ©tude sâest centrĂ©e sur les performances de filtration au dĂ©but de la durĂ©e de vie du filtre Ă manche, avant stabilisation de la perte de charge rĂ©siduelle du filtre rĂ©sultant des prĂ©cĂ©dents cycles de filtration. La perte de charge maximale du filtre Ă©tait fixĂ©e Ă 150 Pa pour tous les cycles de filtration avant dĂ©colmatage par rĂ©tro-soufflage Ă air comprimĂ©. Les performances du filtre Ă manche ont Ă©tĂ© Ă©valuĂ©es en termes dâĂ©volution de sa perte de charge et de son efficacitĂ© de collecte (totale et fractionnelle) au cours des cycles de colmatage/dĂ©colmatage. De plus, des Ă©tudes expĂ©rimentales et thĂ©oriques ont Ă©tĂ© menĂ©es afin dâĂ©tudier lâinfluence de divers paramĂštres sur les performances de filtration du filtre en configuration manche ou plane, tels que lâhumiditĂ© de lâair (3% HR versus 0% HR Ă 150°C), la tempĂ©rature (150°C versus 24°C), la vitesse de filtration (1,9 cm.sâ»Âč versus 1,4 cm.sâ»Âč) et lâinfluence de lâinjection de rĂ©actifs. Les principaux rĂ©sultats de cette Ă©tude sont : (i) importante efficacitĂ© de capture des particules du filtre Ă manche en conditions reprĂ©sentatives des lignes de traitement des fumĂ©es dâincinĂ©ration : efficacitĂ© minimale de collecte de 98,5% mesurĂ©e pour des particules de taille 74 ± 15 nm (diamĂštre de mobilitĂ© Ă©lectrique), (ii) influence du gĂąteau rĂ©siduel de particules au dĂ©but de chaque cycle de filtration sur les performances de traitement, (iii) influence significative de lâhumiditĂ© de lâair sur la structure du gĂąteau de particules probablement due Ă lâaugmentation des forces dâadhĂ©sion entre les particules en prĂ©sence dâhumiditĂ© (150°C â 3% HR soit environ 100 g dâeau par kg dâair sec) ; augmentation plus rapide de la perte de charge du filtre Ă manche en prĂ©sence dâhumiditĂ© (150°C â 3% HR) quâen conditions dâair sec (150°C â 0% HR)
Performances dâun filtre Ă manche pour la capture de particules en conditions reprĂ©sentatives de lâincinĂ©ration de nano-dĂ©chets
Les performances de filtration dâun filtre Ă manche vis-Ă -vis de particules submicroniques et nanomĂ©triques ont Ă©tĂ© Ă©valuĂ©es Ă lâĂ©chelle du laboratoire durant plusieurs cycles de colmatage/dĂ©colmatage. La distribution granulomĂ©trique des particules (aĂ©rosol de combustion) Ă©tait reprĂ©sentative de celle rencontrĂ©e en incinĂ©ration de nano-dĂ©chets en sortie de chambre de combustion Ă lâĂ©chelle du laboratoire. Le filtre Ă manche opĂ©rait en conditions rĂ©alistes, reprĂ©sentatives de celles rencontrĂ©es dans les lignes de traitement des fumĂ©es dâincinĂ©ration de dĂ©chets en termes de tempĂ©rature, humiditĂ©, vitesse de filtration, prĂ©sence de rĂ©actifs et conditions de dĂ©colmatage. Le flux dâair et le filtre Ă manche Ă©taient chauffĂ©s Ă 150°C, la teneur en eau Ă©tait de 10-12% (soit 3% dâhumiditĂ© relative HR), et la vitesse de filtration Ă©tait fixĂ©e Ă 1,9 cm.sâ»Âč. Un mĂ©lange de particules de taille submicronique de charbon actif et de bicarbonate de sodium, utilisĂ©es dans les lignes de traitement des fumĂ©es dâincinĂ©ration pour lâabattement des dioxines/furanes et des gaz acides, Ă©tait gĂ©nĂ©rĂ© simultanĂ©ment avec lâaĂ©rosol de combustion. LâĂ©tude sâest centrĂ©e sur les performances de filtration au dĂ©but de la durĂ©e de vie du filtre Ă manche, avant stabilisation de la perte de charge rĂ©siduelle du filtre rĂ©sultant des prĂ©cĂ©dents cycles de filtration. La perte de charge maximale du filtre Ă©tait fixĂ©e Ă 150 Pa pour tous les cycles de filtration avant dĂ©colmatage par rĂ©tro-soufflage Ă air comprimĂ©. Les performances du filtre Ă manche ont Ă©tĂ© Ă©valuĂ©es en termes dâĂ©volution de sa perte de charge et de son efficacitĂ© de collecte (totale et fractionnelle) au cours des cycles de colmatage/dĂ©colmatage. De plus, des Ă©tudes expĂ©rimentales et thĂ©oriques ont Ă©tĂ© menĂ©es afin dâĂ©tudier lâinfluence de divers paramĂštres sur les performances de filtration du filtre en configuration manche ou plane, tels que lâhumiditĂ© de lâair (3% HR versus 0% HR Ă 150°C), la tempĂ©rature (150°C versus 24°C), la vitesse de filtration (1,9 cm.sâ»Âč versus 1,4 cm.sâ»Âč) et lâinfluence de lâinjection de rĂ©actifs. Les principaux rĂ©sultats de cette Ă©tude sont : (i) importante efficacitĂ© de capture des particules du filtre Ă manche en conditions reprĂ©sentatives des lignes de traitement des fumĂ©es dâincinĂ©ration : efficacitĂ© minimale de collecte de 98,5% mesurĂ©e pour des particules de taille 74 ± 15 nm (diamĂštre de mobilitĂ© Ă©lectrique), (ii) influence du gĂąteau rĂ©siduel de particules au dĂ©but de chaque cycle de filtration sur les performances de traitement, (iii) influence significative de lâhumiditĂ© de lâair sur la structure du gĂąteau de particules probablement due Ă lâaugmentation des forces dâadhĂ©sion entre les particules en prĂ©sence dâhumiditĂ© (150°C â 3% HR soit environ 100 g dâeau par kg dâair sec) ; augmentation plus rapide de la perte de charge du filtre Ă manche en prĂ©sence dâhumiditĂ© (150°C â 3% HR) quâen conditions dâair sec (150°C â 0% HR).Filtration performance of a pulse-jet bag filter was evaluated at the laboratory-scale regarding submicronic particles with a nanosized fraction during clogging/unclogging cycles. The particle size distribution was representative to those encountered at the outlet of a nano-waste incineration device at laboratory-scale. The bag filter was operated in conditions as similar as possible to those found in flue gas treatment of waste incineration plants, in terms of temperature, humidity, filtration velocity, injection of sorbent reagents and unclogging conditions. The air flow and the bag filter were heated to 150°C, the water content was maintained in the air flow in the range of 10-12% (3% of relative humidity RH), and filtration velocity throughout the bag filter was fixed at 1.9 cm.sâ»Âč. A mixture of submicronic suspended particles of activated carbon and sodium bicarbonate, both used in flue gas treatment systems mainly for the removal of dioxins/furans and acid gases, was generated simultaneously with the aerosol representative of combustion emissions.The study focused on the filtration performance at the beginning of the bag filterâs lifetime filter for the 11 first clogging-unclogging cycles before stabilizing the residual pressure drop reached after pulse-jet unclogging. The maximum pressure drop was set at 150 Pa for all filtration cycles. Once the maximum pressure drop was reached, the filter was unclogged using the pulse-jet system. The performance of the bag filter was evaluated in terms of the evolution of pressure drop, fractional and total particle collection efficiencies, during the clogging/unclogging cycles.Moreover, an experimental and theoretical study was carried out on the influence of different parameters on the filtration performance of bag filter and flat filter, such as influence of humidity (3% RH versus 0% RH at 150°C), temperature (150°C versus 24°C), filtration velocity (1.9 cm.sâ»Âč versus 1.4 cm.sâ»Âč) and the influence of the injection of sorbent reagents.The main results of this study are: (i) high collection efficiency of the bag filter in representative conditions of flue gas treatment of waste incineration: minimun particle collection efficiency of 98.5% for particle diameter of 74 ± 15 nm (electrical mobility diameter), (ii) influence of residual particle cake at the beginning of the filtration cycles on the bag filter performance, (iii) significant influence of humidity on the porosity of the particle cake due to the capillary condensation of water between the particles in presence of humidity (150°C - 3% RH i.e. almost 100 g of water per kg of dry air). Faster increase of bag filter pressure drop in presence of humidiy (150°C - 3% RH) as compared to the dry conditions (150°C - 0% RH)
Influence de l'humiditĂ© sur les performances de collecte de particules submicromĂ©triques dâun filtre Ă manche
International audienceFiltration performance of pulse-jet bag filters implemented in flue gas treatment of waste incineration plant was studied at laboratory scale in order to evaluate the influence of humidity during clogging/unclogging cycles. Several cycles of clogging/unclogging with on-line cleaning were done with submicronic particles with a nanosized fraction at the operating conditions as similar as possible to those found in flue gas treatment of waste incineration plants (150°C-3% RH) and in dry conditions (150°C-0% RH). The experimental results revealed a significant influence of humidity on the filtration performance mainly due to capillary condensation, namely faster increase of bag filter pressure drop, lower efficiency of particulate cake dislogment and better collection efficiency of particles between 110 and 300 nm.Les performances de filtration des filtres Ă manche mis en oeuvre dans les lignes de traitement des fumĂ©es dâincinĂ©ration de dĂ©chets ont Ă©tĂ© Ă©tudiĂ©es Ă lâĂ©chelle du laboratoire afin dâĂ©valuer lâinfluence de lâhumiditĂ©. Plusieurs cycles de colmatage et dĂ©colmatage ont Ă©tĂ© rĂ©alisĂ©s Ă lâaide dâun aĂ©rosol reprĂ©sentatif des Ă©missions dâincinĂ©ration de nanodĂ©chets, dâune part pour des conditions opĂ©ratoires reprĂ©sentatives de celles rencontrĂ©es dans les lignes de traitement des fumĂ©es dâincinĂ©ration (150°C- 3% HR) et dâautre part en conditions dâair sec (150°C- 0% HR). Les rĂ©sultats expĂ©rimentaux ont montrĂ© une influence significative de la prĂ©sence dâhumiditĂ© sur les performances de filtration principalement en raison de la condensation capillaire, Ă savoir une augmentation plus rapide de la perte de charge du filtre, un dĂ©colmatage moins efficace du gĂąteau de particules et une efficacitĂ© de collecte des particules entre 110 et 300nm plus importante
MATHEMATICAL AND NUMERICAL MODELING OF NANOPARTICLES TRANSPORT
International audienceThis study aims at numerical simulation of nanoparticle transport in flue-gas treatment at a waste incineration plant. The purpose of this work is to assess the effect of temperature, particle size, and fluid velocity on nanoparticle transport around a single spherical collector considered as a filter medium for nanoparticles filtration. Thus, the stochastic Langevin equation was used to describe the dynamic behavior of particles with account for different forces acting simultaneously on these particles, namely, drag force, gravitational force, and Brownian force. The results indicated, on the one hand, that the effect of temperature on the nanoparticle movement increases with temperature and, on the other hand, that the fluctuation of the particle trajectory is a significant factor in decreasing the particle diameter. Concerning the effect of the fluid velocity, the role of the nanoparticles trajectory becomes more significant the higher the value of the fluid velocity. The results of this work which are expressed as the bivariate velocity and displacement distribution function aim at understanding the experimental filtration efficiency studied in laboratory conditions at two different temperatures and fluid velocities
Filtration performance of lab-scale pulse-jet bag filter
International audienc
Performances de traitement dâun filtre Ă manche de laboratoire en condition de filiĂšre dâincinĂ©ration
International audienc
Understanding the tumor immune escape and the immune modulatory function of cancer stem cells
Cancer therapy is experiencing a paradigm shift due to the clinical success of immune checkpoint inhibitors (ICI), yet efficacy remains limited to a few tumor types and a minority of patients. In an increasing number of cancers, tumor populations called cancer stem cells (CSCs) or tumor-initiating cells (TIC) have been defined. Strong evidence is supporting the immunoresistance feature of CSCs. CSCs can also assist immunosuppression in the Tumor microenvironment (TME) through interaction with other tumor stroma cells. Understanding the mechanisms leading to the immunotolerance of CSCs will be essential for treatment of immune-resistant and metastatic tumors. The identification of such mechanisms faces challenges when applying the widely used transplanted tumor models since they fail to recapitulate the tumor microenvironment as it develops during the progression of human tumors. We previously generated a transgenic model of autochthonous melanoma, named TiRP, which express murine MAGE-type antigen P1A, and can be used as a more faithful preclinical model for immunotherapy. In this model, the CSCs and CTCs are immune resistant. They are devoid of surface MHC I expression and are resistant to both antigen-specific T-cells-and NK-cells-mediated killing. In contrast to non-CSC tumor clones from the TiRP tumor (T429.11), CSCs/CTCs, when transplanted into recipient mice, generate a highly immunosuppressive TME with high numbers of PMN-and Monocytic-MDSCs, and are resistant to immune therapy
Influence of humidity and temperature on bag filter performances for incineration fumes treatment
International audienc
INFLUENCE OF OPERATING CONDITIONS ON BAG FILTER PERFORMANCES FOR INCINERATION FUMES TREATMENT
International audienceFiltration performances of a bag filter implemented for the flue gas treatment of waste incineration plant were studied at laboratory scale in order to evaluate the influence of filtration cycles (clogging/unclogging). The filtration performances were evaluated during clogging with a submicronic aerosol with nano-size fraction, at a filtration velocity of 1.9 cm.s-1. Investigations of the influence of filter washing and filtration velocity on the filtration performances were performed with the same filtering media in flat configuration. Experimental results showed an influence of filtration velocity on fractional filtration efficiency in particular for particle diameter close to the Most Penetrating Particle Size of the filter. Moreover, results indicated that new filters were significantly less efficient than washed filters at the beginning of the clogging. Finally the influence of clogging/unclogging cycles on bag filter performances was demonstrated both for pressure drop and filtration efficiency evolutions during clogging
Influence of air humidity on particle filtration performance of a pulse-jet bag filter
International audienceA pulse-jet bag filter, representative of those implemented in waste incineration plants for flue gas treatment, was studied at laboratory scale to evaluate the influence of air humidity on the filtration performance. Several cycles of clogging/unclogging were performed with non-hygro-scopic submicronic particles with a nanosized fraction with on-line cleaning at operating conditions as similar as possible to those found in the flue gas treatment of waste incineration plants (150°C-73 g/m 3 of absolute humidity), and in dry conditions (150°C). The results revealed a significant influence of air humidity on the bag filter performance: faster increase of bag filter pressure drop during clogging in presence of humidity due to water capillary condensation, lower efficiency of particulate cake unclogging and better collection efficiency of particles between 110 and 300 nm in diameter