Effect of Steam on the Reaction Performance of Oxidative Dehydrogenation of Cyclohexane

2013 ◽  
Vol 781-784 ◽  
pp. 211-214
Author(s):  
Mei Jin ◽  
Li Zhan ◽  
Ping Lu ◽  
Guo Xian Yu
Keyword(s):  
Gas Phase ◽  
Oxidative Dehydrogenation ◽  
Fixed Bed ◽  
Active Species ◽  
Electron Cloud ◽  
Catalyst Characterization ◽  
Oxygen Species ◽  
Oxygen Utilization ◽  
Dehydrogenation Of Cyclohexane ◽  
Reaction Performance

The effect of steam, fed to the fixed-bed microreactor reactor, on the oxidative dehydrogenation of cyclohexane over Mg3(VO4)2 catalyst was reported. The catalyst characterization results showed that the crystal structure, the electron cloud distributions of the active species and the oxygen species, and the reducibility of the active species are not influence by the introduction of steam. It was observed that steam added to the oxidative dehydrogenation of cyclohexane competes for sites required for gas-phase oxygen activation, which catalyst lattice oxygen utilization is not affected. The shorter residence time and the competition for sites with oxygen causes a decrease in cyclohexane conversion and a corresponding increase in selectivity to cyclohexene.

Characterization of Cr−MCM-41 and Al,Cr−MCM-41 Mesoporous Catalysts for Gas-Phase Oxidative Dehydrogenation of Cyclohexane

2007 ◽  
Vol 111 (4) ◽  
pp. 1830-1839 ◽  
Author(s):  
Maria Lezanska ◽  
Grzegorz S. Szymanski ◽  
Piotr Pietrzyk ◽  
Zbigniew Sojka ◽  
Johannes A. Lercher
Keyword(s):  
Gas Phase ◽  
Oxidative Dehydrogenation ◽  
Mesoporous Catalysts ◽  
Dehydrogenation Of Cyclohexane ◽  
Mcm 41

scholarly journals Heterogeneously Catalysed Oxidative Dehydrogenation of Menthol in a Fixed‐Bed Reactor in the Gas Phase

ChemistryOpen ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 1066-1075
Author(s):  
Anna Kulik ◽  
Katja Neubauer ◽  
Reinhard Eckelt ◽  
Stephan Bartling ◽  
Johannes Panten ◽  
...  
Keyword(s):  
Gas Phase ◽  
Oxidative Dehydrogenation ◽  
Fixed Bed ◽  
Fixed Bed Reactor

scholarly journals Cover Feature: Heterogeneously Catalysed Oxidative Dehydrogenation of Menthol in a Fixed‐Bed Reactor in the Gas Phase (ChemistryOpen 8/2019)

ChemistryOpen ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 1034-1034
Author(s):  
Anna Kulik ◽  
Katja Neubauer ◽  
Reinhard Eckelt ◽  
Stephan Bartling ◽  
Johannes Panten ◽  
...  
Keyword(s):  
Gas Phase ◽  
Oxidative Dehydrogenation ◽  
Fixed Bed ◽  
Fixed Bed Reactor

Modeling of aerated upflow fixed bed reactors for nitrification

1999 ◽  
Vol 39 (4) ◽  
pp. 85-92 ◽  
Author(s):  
J. Behrendt
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Liquid Phase ◽  
Gas Phase ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bulk Liquid ◽  
Initial Value ◽  
Fixed Bed Reactors ◽  
Number Of Cells

A mathematical model for nitrification in an aerated fixed bed reactor has been developed. This model is based on material balances in the bulk liquid, gas phase and in the biofilm area. The fixed bed is divided into a number of cells according to the reduced remixing behaviour. A fixed bed cell consists of 4 compartments: the support, the gas phase, the bulk liquid phase and the stagnant volume containing the biofilm. In the stagnant volume the biological transmutation of the ammonia is located. The transport phenomena are modelled with mass transfer formulations so that the balances could be formulated as an initial value problem. The results of the simulation and experiments are compared.

The Effects of Preparation Methods on Iron Structures of Iron-Supported HZSM-5 and their Catalytic Performance for Methanol Dehydration

2016 ◽  
Vol 723 ◽  
pp. 633-639
Author(s):  
Waenkaew Pantupho ◽  
Arthit Neramittagapong ◽  
Nuttawut Osakoo ◽  
Jatuporn Wittayakun ◽  
Sirinuch Loiha
Keyword(s):  
Flow Reactor ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Active Species ◽  
Iron Complex ◽  
Methanol Dehydration ◽  
Low Carbon ◽  
Zeolite Framework ◽  
Preparation Methods ◽  
Binuclear Iron

Iron-supported HZSM-5 catalysts were prepared by hydrothermal (Fe-HZSM-5_HYD) and impregnation methods (Fe/HZSM-5_IMP). The active species of binuclear-iron complex and iron-substituted zeolite framework, confirmed by EXAFS analysis, were observed on Fe/HZSM-5_IMP and Fe-HZSM-5_HYD, respectively. The catalysts were used for production of dimethyl ether (DME) by methanol dehydration at 200-350 °C using fixed bed flow reactor. Fe/HZSM-5_IMP showed higher catalytic conversion than Fe-HZSM-5_HYD. However, the Fe/HZSM-5_IMP catalyst was less selective to DME product and strongly deactivated for 24h. The deactivation might due to transformation of binuclear-iron to the a-iron site which was strong acidic strengh. The iron-substituted zeolite framework of Fe-HZSM-5_HYD showed high stability toward methanol dehydration. Moreover, the catalyst showed advantages of good selective to DME and low carbon deposition on surface. These results suggested that the iron-substituted zeolite framework structure could improve catalytic performance for mrthanol dehydration.

Effects of Air Flowrate on the Combustion and Emissions of Blended Corn Straw and Pinewood Wastes

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Honghua Zhao ◽  
Rui Sun ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ignition Delay Time ◽  
Fixed Bed ◽  
Combustion Efficiency ◽  
Fixed Bed Reactor ◽  
Corn Straw ◽  
Excess Air ◽  
Burning Rates ◽  
Excess Air Coefficient ◽  
Hazardous Pollutants

This research investigated the effects of the specific primary (under-fire) air flowrate (m˙air) on the combustion behavior of a 50–50 wt % blend of raw corn straw (CS) and raw pinewood wastes in a fixed-bed reactor. This parameter was varied in the range of 0.079–0.226 kg m−2 s−1, which changed the overall combustion stoichiometry from air-lean (excess air coefficient λ = 0.73) to air-rich (excess air coefficient λ = 1.25) and affected the combustion efficiency and stability as well as the emissions of hazardous pollutants. It was observed that by increasing m˙air, the ignition delay time first increased and then decreased, the average bed temperatures increased, both the average flame propagation rates and the fuel burning rates increased, and the combustion efficiencies also increased. The emissions of CO as well as those of cumulative gas phase nitrogen compounds increased, the latter mostly because of increasing HCN, while those of NO were rather constant. The emissions of HCl decreased but those of other chlorine-containing species increased. The effect of m˙air on the conversion of sulfur to SO2 was minor. By considering all of the aforesaid factors, a mildly overall air-rich (fuel-lean) (λ = 1.04) operating condition can be suggested for corn-straw/pinewood burning fixed-bed grate-fired reactors.

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