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Fixed Bed Reactor (fixed + bed_reactor)
Selected AbstractsKinetics and mechanism of the oxidation of carbon by NO2 in the presence of water vaporINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 4 2009M. Jeguirim The kinetics and mechanism of the oxidation of carbon by NO2 in absence and presence of water vapor were studied in a fixed bed reactor. The rate of carbon oxidation by NO2 is enhanced in the presence of water vapor in the range of temperature 300,400°C. The benefit effect of water is attributed to the intermediate formation of traces of nitric and nitrous acids, which enhance the rate of the carbon oxidation without modifying the global mechanism reaction. Therefore, water acts as a catalyst for the carbon oxidation by NO2. A kinetic mechanism derived from this parametric study shows a decrease in the activation energy of carbon oxidation by NO2 in the presence of water vapor. This result is in agreement with the experimental observation. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 236,244, 2009 [source] Thermal processing of biomass natural fibre wastes by pyrolysisINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 2 2004Anton R. Reed Abstract Waste biomass material in the form of natural fibres used in the production of textile products were examined for their potential to produce activated carbon by physical activation. The five biomass types were hemp, flax, jute, coir and abaca. Each biomass was pyrolysed in a fixed bed reactor and the char characterized. The char was subsequently, activated with steam in a char activation reactor. The surface area and porosity of the derived activated carbon was determined. Surface areas of between 770 and 879 m2 g,1 were achieved. The yield of activated carbon was mostly less than 20 wt% of the original biomass. The five biomass samples were also pyrolysed in a thermogravimetric analyser. The thermal degradation of the biomas samples were discussed in terms of the thermal degradation of the main components of the biomass, cellulose, hemicellulose and lignin. Copyright © 2004 John Wiley & Sons, Ltd. [source] Hydrocarbon gases and oils from the recycling of polystyrene waste by catalytic pyrolysisINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2004Paul T. Williams Abstract The yield and composition of oils and gases derived from the pyrolysis and catalytic pyrolysis of polystyrene has been investigated. The pyrolysis and catalytic pyrolysis was carried out in a fixed bed reactor. Two catalysts were used, zeolite ZSM-5 and Y-zeolite and the influence of the temperature of the catalyst, the amount of catalyst loading and the use of a mixture of the two catalysts was investigated. The main product from the uncatalysed pyrolysis of polystyrene was an oil consisting mostly of styrene and other aromatic hydrocarbons. The gases were found to consist of methane, ethane, ethene, propane, propene, butane and butene. In the presence of either catalyst an increase in the yield of gas and decrease in the amount of oil produced was found, but there was significant formation of carbonaceous coke on the catalyst. Increasing the temperature of the Y-zeolite catalyst and also the amount of catalyst in the catalyst bed resulted in a decrease in the yield of oil and increase in the yield of gas. Copyright © 2004 John Wiley & Sons, Ltd. [source] Epoxidation of allyl chloride and hydrogen peroxide over titanium silicalite-1 film on SiO2 pellet supportJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2007Li Wang Abstract Titanium silicalite-1 (TS-1) films were prepared on SiO2 pellet supports via an in situ hydrothermal synthesis method and were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and 29Si magic angle spinning nuclear magnetic resonance (Si MAS NMR). The growth time of TS-1 film had a strong effect on its morphology and the thickness and size of the crystals. The uniformity and thickness of TS-1 films increased with increase of growth times. The epoxidation of allyl chloride (ACH) with dilute hydrogen peroxide to form epichlorohydrin (ECH) over the TS-1 films was carried out in a fixed bed reactor. The conversion of ACH and the selectivity to ECH over the TS-1 films of the second growth were higher than that of the first growth, the third and the fourth growth. And the conversion and selectivity as a function of time-on-stream gave a good stable performance in an extended test up to at least 19 h. The final steady-state conversion and selectivity were approximately 86% and 55%, respectively. Copyright © 2007 Society of Chemical Industry [source] A novel inorganic hollow fiber membrane reactor for catalytic dehydrogenation of propaneAICHE JOURNAL, Issue 9 2009Zhentao Wu Abstract A novel inorganic hollow fiber membrane reactor (iHFMR) has been developed and applied to the catalytic dehydrogenation of propane to propene. Alumina hollow fiber substrates, prepared by a phase inversion/sintering method, possess a unique asymmetric structure that can be characterized by a very porous inner surface from which finger-like voids extend across ,80% of the fiber cross-section with the remaining 20% consisting of a denser sponge-like outer layer. In contrast to other existing Pd/Ag composite membranes, where an intermediate ,-Al2O3 layer is often used to bridge the Pd/Ag layer and the substrate, the Pd/Ag composite membrane prepared in this study was achieved by coating the Pd/Ag layer directly onto the outer surface of the asymmetric substrate. After depositing submicron-sized Pt (0.5 wt %)/,-alumina catalysts in the finger-like voids of the substrates, a highly compact multifunctional iHFMR was developed. Propane conversion as high as 42% was achieved at the initial stage of the reaction at 723 K. In addition, the space-time yields of the iHFMR were ,60 times higher than that of a fixed bed reactor, demonstrating advantages of using iHFMR for dehydrogenation reactions. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] A novel continuous reactor for catalytic reduction of NOx,fixed bed simulationsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2008Terris T. Yang Abstract A novel dual-zone fluidized bed reactor was proposed for the continuous adsorption and reduction of NOx from combustion flue gases. The adsorption and reaction behaviour of such a reactor has been simulated in a fixed bed reactor using Fe/ZSM-5 catalyst and propylene reductant with model flue gases. Fe/ZSM-5 exhibited acceptable activity at T,=,350°C and GHSV,=,5000 h,1 when O2 concentration was controlled at levels lower than 1% with a HC to NO molar ratio of about 2:1. XPS and BET surface area measurement revealed the nature of the deactivation of the catalyst. Those performance data demonstrated the feasibility of a continuous dual-zone fluidized bed reactor for catalytic reduction of NOx under lean operating conditions. Un nouveau réacteur à lit fluidisé à double zone est proposé pour l'adsorption et la réduction en continu de NOx à partir de gaz de carneau de combustion. Le comportement d'adsorption et de réaction d'un tel réacteur a été simulé dans un réacteur à lit fixe utilisant un catalyseur Fe/ZSM-5 et un agent réducteur avec des gaz de carneau modèle. Le Fe/ZSM-5 montre une activité acceptable à T,=,350°C et GHSV,=,5000 h,1 lorsque la concentration d'O2 est contrôlée à des niveaux inférieurs à 1% avec un rapport molaire HC,NO d'environ 2:1. La mesure de surface par XPS et BET a permis de caractériser la désactivation du catalyseur. Ces données de performance illustre la faisabilité du réacteur à lit fluidisé à double zone Fe/ZSM-5 pour la réduction catalytique de NOx dans des conditions opératoires pauvres. [source] Catalytic Combustion of Ethyl Acetate over Nanostructure Cobalt Supported ZSM-5 Zeolite CatalystsCHINESE JOURNAL OF CHEMISTRY, Issue 3 2009Aligholi NIAEI Abstract Gas phase catalytic combustion of ethyl acetate, as one of volatile organic compounds (VOC), was studied on nanostructure ZSM-5, HZSM-5 and Co-ZSM-5 with different cobalt loadings. Nanostructure of ZSM-5 was determined by XRD, SEM and TEM. Catalytic studies were carried out under atmospheric pressure in a fixed bed reactor. Results showed that the Co-ZSM-5 catalysts had better activity than others and at temperatures below 350 °C, amount of Co loading was more effective on catalytic activity. The order of conversion of ethyl acetate over different Co loading is as follows: Co-ZSM-5 (0.75 wt%)
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