CONVERSION OF D-XYLOSE TO CARBOXYLIC ACIDS IN A CAPILLARY FLUIDIZED BED

摘要: La demande pour remplacer les combustibles fossiles par la biomasse renouvelable est grande. Nous recherchons des facons de convertir glucides en produits plus grande valeur. Peu d’etudes ont ete faites a haute temperature et presque aucune experience n’a examine l’oxydation partielle catalytique temperature. Il nous faut criteres conception exploiter cette technologie facon commerciale. Nous presentons une nouvelle methode valoriser sucres C5 faisons revue l’etat actuel reactions C5. voulions developper conditions optimales production d’acides desirables eventuellement tester nouveaux catalyseurs d’autres applications. Nous avons etudie heterogene phase gazeuse du xylose dans un reacteur gaz-solide lit fluidise capillaire relativement pression atmospherique. oxyde le sucre systeme trois catalyseurs, soit pyrophosphate vanadyle, trioxyde molybdene-oxyde cobalt molybdate fer, former acides organiques anhydrides. injecte solution eau-sucre dont composante principale etait tube quartz (ID = 8 mm) four qui operait jusqu’a 1000 °C. determine plage operatoires avec etude reconnaissance ensuite prepare plan d’experience. Les facteurs importants etaient (200–550 °C), concentration (3 %poids, 7 10 %poids eau), temps sejour (0,1 s, 0,2 s), d’oxygene (0 %vol, 3 21 %vol azote) catalyseur (VPP, MoO3/CoO, FeMoO). co-alimente l’azote ameliorer l’atomisation. D’autres parametres affectent l’atomisation sont rapport gaz-liquide (0,1–0,2 %poids), debit liquide (0,01–0,1 ml min-1) diametre bout buse capillaire. avions quatre categories d’atomisation : ‘a’, ‘b’, ‘c’ ‘d’ ordre decroissant performance. utilise type ‘a’ verifier l’effet autres ‘b’ performance sur rendement. egalement teste l’alimentation sequentielle xylose-oxygene l’air frequence 5 min-1. Pour productivite fait experiences 2 h 4 h. Le 0.2 s duraient h. Le gaz fluidisation contenait azote entrait distributeur verre fritte. d’entree variait entre 80–150 min-1 avoir l’oxygene %vol. 1 g VPP calcine. Une pompe seringue alimente 0.04 atomise gouttelettes 0.25 mm serre l’extremite buse. 0.18 % poids produire jet effervescent. se vaporisees rapidement reagit l’anhydride maleique, l’acide acrylique l’acroleine. Une serie trempes absorbe liquides (les acides) l’effluent eau distillee. echantillonne analyse accumules HPLC hors ligne. valider l’analyse identifier possibles, chromatographie (GC). Les d’operation effet distribution taux production. L’acide desirable maleique abondant. vanadyl actif selectif ce procede. Dans meilleur cas, 300 °C d’oxygene, rendements l’acroleine 25 %, 17 11 respectivement. detecte CO2 gazeux GCMS lors reaction. L’analyse thermogravimetrique echantillons confirme qu’aucun coke ne s’est forme catalyseur. L’agglomeration caramelisation poudre n’etaient problematiques que etablies haut. ---------- The demand for renewable biomass as replacement fossil fuels has never been greater. Many paths to convert carbohydrates into higher value products are under investigation. Few studies have reported data at high and almost no experiments examined catalytic partial oxidation of carbohydrates. We need generalized design criteria exploit this technology commercially. We present new method valorize sugars review state the art sugar reactions. wanted develop optimal process produce acids eventually test catalysts other applications. We studied gas heterogeneous in gas-solid capillary fluidized bed reactor relatively atmospheric pressure. oxidized over three catalyst system (vanadyl pyrophosphate, molybdenum trioxide-cobalt oxide iron molybdate) form organic acids/anhydrides. injected water-sugar whose main component is furnace that operates up range possible operating with scouting study then made an experimental design. The most important factors were (200-550 %wt, %wt water), residence time (0.1 oxygen pressure nitrogen), Co-feeding nitrogen improved atomization. Parameters affected atomization gas-to-liquid ratio (0.1-0.2 %wt), liquid flow rate (0.01-0.1 min-1), nozzle tip diameter. had spray performance: decreasing order used mixed including two factors: temperatures (300 °C, 350 400 450 °C) pressures %vol) catalyst. verify effect parameters on yield. also tested sequentially feeding xylose-oxygen followed by air frequency included runs stability. Residence inside was lasted fluidization contained entered through fritted glass distributor. inlet fluidizing stream varied between 80-150 ml/min meet oxygen. carried out calcined metered syringe pump. atomized small drops constricted end nozzle. fed effervescent spray. droplets vapourized rapidly reacted maleic anhydride, acrylic acid acrolein. We absorbed (acids) from effluent distilled water series quenches. sampled analyzed accumulated offline chromatography (HPLC). validated analysis (GC) tried identify products. Operating considerable product rates. Acrylic abundant. Vanadyl both active selective best case, oxygen, acid, acrolein yields respectively. detected gaseous carbon dioxide during Thermogravimetric samples we withdrew reaction confirmed formed Powder agglomeration caramelization only problematic when operated outside established experiments.