Gazéification de la biomasse en réacteur à flux entrainé : études expérimentales et modélisation

The present work deals with biomass gasification in Entrained Flow Reactor (EFR) in the context of the development of new Biomass-to-Liquid processes. The objective of this study is to develop a comprehensive model to better understand the phenomena controlling biomass gasification in conditions representative of an EFR. Biomass pyrolysis and gasification of beech particles sieved between 315 and 450 µm have been studied between 800 and 1400°C in a drop tube furnace. The influence of H2O, CO2 and O2 addition on gasification products has been investigated and the tests have been simulated with a 1D model. The addition of H2O or CO2 leads to a significantly lower char yield. The main influence of these two oxidants in gas phase is the modification of major species composition with water gas shift reaction. With the addition of O2, the carbon conversion into gas is improved and the char and soot yields are significantly lower. The simulations are in very good agreement with the experimental results. Biomass pyrolysis and gasification of beech particles sieved between 1.12 and 1.25 mm have been studied in presence of O2. Between 800 and 1200°C the carbon conversion into gas is lower than with the smaller particles but at 1400°C the particle size has no influence. At last, the influence of O2 addition, particle size and pressure on biomass gasification has been studied in a pilot scale EFR. These experimental results have been satisfactorily simulated by adapting the 1D model.Ce travail porte sur l'étude de la gazéification de biomasse en Réacteur à Flux Entrainé (RFE), dans le contexte du développement de procédés pour la production de biocarburants de deuxième génération. L'objectif de cette thèse est de modéliser les différents phénomènes qui régissent la conversion de la biomasse dans des conditions représentatives d'un RFE. La pyrolyse et la gazéification de particules de hêtre de taille comprise entre 315 et 415 µm ont été étudiées entre 800 et 1400°C en four à chute de laboratoire. L'influence de l'ajout de H2O, de CO2 et de O2 sur les produits de gazéification a été explorée, et les essais ont été simulés à partir d'un modèle 1D. L'ajout de H2O ou de CO2 permet de diminuer les rendements en char de manière significative. En phase gaz, l'influence principale de ces deux espèces est la modification de la composition en espèces majoritaires avec la réaction de gaz à l'eau. L'ajout de O2 a pour effet d'améliorer la conversion du carbone de la biomasse en gaz, et de réduire de manière significative la production de suies et de char. Le modèle, basé sur une chimie détaillée, permet de simuler ces essais de façon très satisfaisante sur toute la gamme de variation des conditions opératoires. La pyrolyse et la gazéification de particules de hêtre tamisées entre 1,12 et 1,25 mm a été étudiée en présence de O2. À 800, 1000 et 1200°C, la conversion de ces « grosses » particules est plus faible que celles des petites particules, mais à 1400°C la taille de particule n'a pas d'influence. Enfin, une étude expérimentale a été menée dans un RFE pilote pour étudier l'influence de la quantité de O2, de la taille de particule et de la pression sur la gazéification de particules de bois. Ces essais ont été simulés de façon satisfaisante en adaptant le modèle 1D

Progranulin signaling in sepsis, community-acquired bacterial pneumonia and COVID-19: a comparative, observational study

BACKGROUND Progranulin is a widely expressed pleiotropic growth factor with a central regulatory effect during the early immune response in sepsis. Progranulin signaling has not been systematically studied and compared between sepsis, community-acquired pneumonia (CAP), COVID-19 pneumonia and a sterile systemic inflammatory response (SIRS). We delineated molecular networks of progranulin signaling by next-generation sequencing (NGS), determined progranulin plasma concentrations and quantified the diagnostic performance of progranulin to differentiate between the above-mentioned disorders using the established biomarkers procalcitonin (PCT), interleukin-6 (IL-6) and C-reactive protein (CRP) for comparison. METHODS The diagnostic performance of progranulin was operationalized by calculating AUC and ROC statistics for progranulin and established biomarkers in 241 patients with sepsis, 182 patients with SIRS, 53 patients with CAP, 22 patients with COVID-19 pneumonia and 53 healthy volunteers. miRNAs and mRNAs in blood cells from sepsis patients (n = 7) were characterized by NGS and validated by RT-qPCR in an independent cohort (n = 39) to identify canonical gene networks associated with upregulated progranulin at sepsis onset. RESULTS Plasma concentrations of progranulin (ELISA) in patients with sepsis were 57.5 (42.8-84.9, Q25-Q75) ng/ml and significantly higher than in CAP (38.0, 33.5-41.0~ng/ml, p < 0.001), SIRS (29.0, 25.0-35.0~ng/ml, p < 0.001) and the healthy state (28.7, 25.5-31.7~ng/ml, p < 0.001). Patients with COVID-19 had significantly higher progranulin concentrations than patients with CAP (67.6, 56.6-96.0 vs. 38.0, 33.5-41.0~ng/ml, p < 0.001). The diagnostic performance of progranulin for the differentiation between sepsis vs. SIRS (n = 423) was comparable to that of procalcitonin. AUC was 0.90 (95% CI = 0.87-0.93) for progranulin and 0.92 (CI = 0.88-0.96, p = 0.323) for procalcitonin. Progranulin showed high discriminative power to differentiate bacterial CAP from COVID-19 (sensitivity 0.91, specificity 0.94, AUC 0.91 (CI = 0.8-1.0) and performed significantly better than PCT, IL-6 and CRP. NGS and partial RT-qPCR confirmation revealed a transcriptomic network of immune cells with upregulated progranulin and sortilin transcripts as well as toll-like-receptor 4 and tumor-protein 53, regulated by miR-16 and others. CONCLUSIONS Progranulin signaling is elevated during the early antimicrobial response in sepsis and differs significantly between sepsis, CAP, COVID-19 and SIRS. This suggests that progranulin may serve as a novel indicator for the differentiation between these disorders. TRIAL REGISTRATION Clinicaltrials.gov registration number NCT03280576 Registered November 19, 2015

Clinical Pharmacokinetics and Dose Recommendations for Posaconazole in Infants and Children.

OBJECTIVES: The objectives of this study were to investigate the population pharmacokinetics of posaconazole in immunocompromised children, evaluate the influence of patient characteristics on posaconazole exposure and perform simulations to recommend optimal starting doses. METHODS: Posaconazole plasma concentrations from paediatric patients undergoing therapeutic drug monitoring were extracted from a tertiary paediatric hospital database. These were merged with covariates collected from electronic sources and case-note reviews. An allometrically scaled population-pharmacokinetic model was developed to investigate the effect of tablet and suspension relative bioavailability, nonlinear bioavailability of suspension, followed by a step-wise covariate model building exercise to identify other important sources of variability. RESULTS: A total of 338 posaconazole plasma concentrations samples were taken from 117 children aged 5 months to 18 years. A one-compartment model was used, with tablet apparent clearance standardised to a 70-kg individual of 15 L/h. Suspension was found to have decreasing bioavailability with increasing dose; the estimated suspension dose to yield half the tablet bioavailability was 99 mg/m2. Diarrhoea and proton pump inhibitors were also associated with reduced suspension bioavailability. CONCLUSIONS: In the largest population-pharmacokinetic study to date in children, we have found similar covariate effects to those seen in adults, but low bioavailability of suspension in patients with diarrhoea or those taking concurrent proton pump inhibitors, which may in particular limit the use of posaconazole in these patients

Pubertal development of transfusion-dependent thalassemia patients in the era of oral chelation with deferasirox: results from the French registry

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Biomass gasification in entrained flow reactor : experiments and modeling

Ce travail porte sur l'étude de la gazéification de biomasse en Réacteur à Flux Entrainé (RFE), dans le contexte du développement de procédés pour la production de biocarburants de deuxième génération. L'objectif de cette thèse est de modéliser les différents phénomènes qui régissent la conversion de la biomasse dans des conditions représentatives d'un RFE. La pyrolyse et la gazéification de particules de hêtre de taille comprise entre 315 et 415 µm ont été étudiées entre 800 et 1400°C en four à chute de laboratoire. L'influence de l'ajout de H2O, de CO2 et de O2 sur les produits de gazéification a été explorée, et les essais ont été simulés à partir d'un modèle 1D. L'ajout de H2O ou de CO2 permet de diminuer les rendements en char de manière significative. En phase gaz, l'influence principale de ces deux espèces est la modification de la composition en espèces majoritaires avec la réaction de gaz à l'eau. L'ajout de O2 a pour effet d'améliorer la conversion du carbone de la biomasse en gaz, et de réduire de manière significative la production de suies et de char. Le modèle, basé sur une chimie détaillée, permet de simuler ces essais de façon très satisfaisante sur toute la gamme de variation des conditions opératoires. La pyrolyse et la gazéification de particules de hêtre tamisées entre 1,12 et 1,25 mm a été étudiée en présence de O2. À 800, 1000 et 1200°C, la conversion de ces « grosses » particules est plus faible que celles des petites particules, mais à 1400°C la taille de particule n'a pas d'influence. Enfin, une étude expérimentale a été menée dans un RFE pilote pour étudier l'influence de la quantité de O2, de la taille de particule et de la pression sur la gazéification de particules de bois. Ces essais ont été simulés de façon satisfaisante en adaptant le modèle 1D.The present work deals with biomass gasification in Entrained Flow Reactor (EFR) in the context of the development of new Biomass-to-Liquid processes. The objective of this study is to develop a comprehensive model to better understand the phenomena controlling biomass gasification in conditions representative of an EFR. Biomass pyrolysis and gasification of beech particles sieved between 315 and 450 µm have been studied between 800 and 1400°C in a drop tube furnace. The influence of H2O, CO2 and O2 addition on gasification products has been investigated and the tests have been simulated with a 1D model. The addition of H2O or CO2 leads to a significantly lower char yield. The main influence of these two oxidants in gas phase is the modification of major species composition with water gas shift reaction. With the addition of O2, the carbon conversion into gas is improved and the char and soot yields are significantly lower. The simulations are in very good agreement with the experimental results. Biomass pyrolysis and gasification of beech particles sieved between 1.12 and 1.25 mm have been studied in presence of O2. Between 800 and 1200°C the carbon conversion into gas is lower than with the smaller particles but at 1400°C the particle size has no influence. At last, the influence of O2 addition, particle size and pressure on biomass gasification has been studied in a pilot scale EFR. These experimental results have been satisfactorily simulated by adapting the 1D model

Influence of H2O, CO2 and O-2 addition on biomass gasification in entrained flow reactor conditions: Experiments and modelling

International audienceBiomass gasification in Entrained Flow Reactor (EFR) is both studied with experiments in a drop tube reactor and modelling with a 1-D model (GASPAR). Operating conditions are chosen thanks to results of a preliminary modelling of an industrial EFR. Influence of addition of steam (0.55 g/g db), carbon dioxide (0.87 g/g db) and oxygen (Equivalent Ratio: 0-0.61) is investigated between 800 and 1400 degrees C with beech wood particles sieved between 315 and 450 mu m as feedstock. The model takes into account pyrolysis reaction, gas phase reaction with a detailed chemical scheme (176 species, 5988 reactions), char gasification by steam and CO2 and soot formation. H2O or CO2 addition has no influence on gasification product yields at 800 and 1000 degrees C, while at 1200 and 1400 degrees C the char gasification is significantly enhanced and soot formation is certainly inhibited by OH radical which reacts with soot precursors. The modification of output gas phase composition is mostly due to WGS reaction which reaches thermodynamic equilibrium from about 1200 degrees C. As expected, O-2 has a significant influence on gas and tar yields through combustion reactions. Char and soot yields decrease as ER increases. The GASPAR model allows a good prediction of gas and char and gives relevant evolution of soot and tar yields on the large majority of conditions studied

La Bouderie, essai psychologique et psychopathologique... / Raymond, Aimé, Joseph Billaud,...

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Biomass fast pyrolysis in a drop tube reactor for bio oil production: Experiments and modeling

International audienceWoody biomass fast pyrolysis in Entrained Flow Reactor (EFR) is studied both with experiments in a lab-scale drop tube reactor (DTR) and simulations with a 1-D model. The parameters of the study are temperature (450-600 degrees C), woody biomass particle size (370-640 mu m) and gas residence time (12.6-20.6 s). The most critical phenomena affecting the bio-oil yield are considered in the model: heating of the biomass particles, slip velocity of the biomass particles varying with biomass/char properties, biomass pyrolysis and tar cracking. The analyses of all products - char, bio-oil and gas - also brought information on the advancement of the pyrolysis and cracking for the different tests. The reactor temperature and particle size were found to have a major influence on the pyrolysis product distribution. The production of bio-oil reaches a maximum of 62.4 wt.% at 500 degrees C for the 370 mm particles. The particle conversion advancement is then estimated at 94% at the reactor exit. The bio-oil yield is lower at higher temperatures for a constant particle size due to tar cracking. At 550 degrees C, increasing the particle size from 370 mm to 640 mu m induces a decrease of the bio-oil yield from 48.3 to 34.8 wt.%, which was shown to be due to incomplete pyrolysis of the particles, because of a too short residence time as well as a too long heating time of particles. The pyrolysis conditions - temperature, particle size - were not found to have any significant influence on the bio-oil properties, such as acidity

Discussion sur les démissions de Billaud et Collot comme membres du comité de Salut public, lors de la séance du 15 fructidor an II (1er septembre 1794)

Duhem Pierre-Joseph, Cambon Pierre-Joseph, Billaud-Varenne, Collot d'Herbois Jean-Marie. Discussion sur les démissions de Billaud et Collot comme membres du comité de Salut public, lors de la séance du 15 fructidor an II (1er septembre 1794). In: Archives Parlementaires de 1787 à 1860 - Première série (1787-1799) Tome XCVI - Du 10 fructidor au 22 fructidor an II (27 août au 8 septembre 1794) Paris : CNRS éditions, 1990. p. 176