scholarly journals An experimental study of the partial oxidation of ethane to ethylene in a shallow fluidized bed reactor

2007 ◽  
Vol 72 (2) ◽  
pp. 183-192 ◽  
Author(s):  
Danica Brzic ◽  
Desislava Ahchieva ◽  
Mirko Peglow ◽  
Stefan Heinrich
Keyword(s):  
Fluidized Bed ◽  
Atmospheric Pressure ◽  
Contact Time ◽  
Rectangular Cross Section ◽  
Fluidized Bed Reactor ◽  
Oxygen Excess ◽  
Ethylene Selectivity ◽  
Dilute System ◽  
Pure Al2o3 ◽  
Catalytic Performances

The partial catalytic oxidation of ethane to ethylene was investigated experimentally in a shallow fluidized bed. The performances of two catalyst types, pure ?-Al2O3 and V2O5/?-Al2O3 particles 1.8 mm in diameter, were analyzed. A pilot fluidized bed reactor with rectangular cross-section of 100mmx100mm was used. The experiments were carried out under atmospheric pressure in a dilute system under oxygen excess conditions. V2O5/?-Al2O3 showed good catalytic performances regarding ethylene selectivity. The influence of the temperature (in the range of 400-600?C) and the contact time (in the range of 35-85 kg s m-3) on the conversion of ethane and the selectivity to ethylene was analyzed. The highest yield of ethylene was 18%. .

Phosphate removal in real anaerobic supernatants: modelling and performance of a fluidized bed reactor

1998 ◽  
Vol 38 (1) ◽  
pp. 275-283 ◽  
Author(s):  
P. Battistoni ◽  
P. Pavan ◽  
F. Cecchi ◽  
J. Mata-Alvarez
Keyword(s):  
Fluidized Bed ◽  
Contact Time ◽  
Fluidized Bed Reactor ◽  
Phosphate Removal ◽  
Plant Design ◽  
Air Stripping ◽  
And Performance ◽  
Ph Range ◽  
Very High ◽  
A2o Process

Phosphate removal in anaerobic supernatant coming from a centrifugation sludge station of an A2O process is studied. A fluidized bed reactor is employed to crystallize phosphate as hydroxyapatite or struvite using only air stripping to reach the supersaturation pH. The classic composition of supernatant (alkalinity 3550 mgCaCO3/l, PO4 139 mg/l, Mg 24 mg/l) does not require any addition of chemicals for phosphate removal. Seventeen runs are performed in a bench scale FBR obtaining very high conversion and removal efficiency and phosphate loss in the effluent ≤3.5%. The use of Ca or Mg enriched supernatant has no meaningful influence on efficiency, but it determines the prevalent salt formed between MAP or HAP. Efficiency can be related to pH and sand contact time in a double saturational model. The half efficiency constants: 0.075 h for t and 7.75 pH, have an important role in the process knowledge and optimization of plant design. Exhaust sand analysis indicates the same composition at the top, bottom and mean of the sand bed (39% mol MAP and 61% mol HAP). This result together with the high half efficiency constant for contact time indicate that the phosphate growth on the bed is not competitive. Finally, the phosphate release from the plant is studied. Results show a weak release rate, equivalent to 2.8-10% d−1 phosphate as MAP, obtained at an operative pH range of 8.1-8.4.

Understanding the Effect of the Transition Period during the Air Gasification of Dried Sewage Sludge in a Fluidized Bed Reactor

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
María Aznar ◽  
Ángel E. González ◽  
Joan J Manyà ◽  
José L. Sánchez ◽  
M Benita Murillo
Keyword(s):  
Steady State ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Atmospheric Pressure ◽  
Transition Period ◽  
Fluidized Bed Reactor ◽  
Operating Conditions ◽  
Polycyclic Aromatic ◽  
Reactor Temperature ◽  
Composition Changes

Air gasification of dried sewage sludge (DSS) in a fluidized bed has been studied as an effective alternative for the management of this material in a usable way. Nevertheless, one of the major issues in this technology is to deal with the tar formed during the process. To minimize the tar production, it is very important to optimize the operating conditions. In a previous work (Manyà et al., Energy Fuels, Vol. 19, 629–636, 2005) some unexpected results, in which tar production increases with the equivalence ratio, have been obtained. As it has been mentioned in that work, tar production could present unexpected trends while the bed composition changes from sand to a mixture of char and sand. Ashes contained in char have catalytic active metals which could promote gasification reactions. As the char content in the bed increases, the catalytic activity in the reactor could increase too, until the steady state is achieved. The aim of this work is to characterize the non-stationary period and its influence on the overall results obtained from gasification tests. Experiments have been carried out in a laboratory-scale BFB reactor at atmospheric pressure and at a reactor temperature of 1123 K with an equivalent ratio of 30%. Results show that at the beginning of the experiments the tar production was higher, until the steady state is reached. The gasification study has been enhanced with an analysis of tar composition by means of GC/MS and GC/FID. An effect of the transition period has been observed in tar composition also. The nitrogen aromatics percent increased with time whereas the polycyclic aromatic hydrocarbon decreased.

Polymer Powder Treatment in Atmospheric Pressure Plasma Circulating Fluidized Bed Reactor

2014 ◽  
Vol 12 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Gina Oberbossel ◽  
Andreas Thomas Güntner ◽  
Lukas Kündig ◽  
Christian Roth ◽  
Philipp Rudolf von Rohr
Keyword(s):  
Fluidized Bed ◽  
Atmospheric Pressure ◽  
Circulating Fluidized Bed ◽  
Atmospheric Pressure Plasma ◽  
Fluidized Bed Reactor ◽  
Pressure Plasma ◽  
Polymer Powder

scholarly journals Catalytic oxidation of methanol in the cenospheric fluidized bed

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1231-1240
Author(s):  
Gabriela Berkowicz ◽  
Jan Wrona ◽  
Jerzy Baron ◽  
Dariusz Bradlo ◽  
Witold Zukowski
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Oxidation ◽  
Fluidized Bed ◽  
Molecular Hydrogen ◽  
Contact Time ◽  
Fluidized Bed Reactor ◽  
Catalyst Preparation ◽  
Complete Degradation ◽  
Oxidation Of Methanol ◽  
Two Stages

The process of oxidation of gaseous CH3OH by N2O was carried out over an Ag-Fe2O3-cenosphere catalyst whose structure can be defined as double shell-core catalyst. Preparation of the catalyst was carried out in two stages: thermal decomposition of Fe(CO)5 at above 160?C and then electroless Ag plating. The process of methanol degradation by N2O was carried out in a fluidized bed reactor. The study confirms that it is possible to achieve complete degradation of N2O and CH3OH for the obtained catalyst at above 450?C when the contact time of the reactants with the catalyst is approximately 6 second and when the substrates are used in stoichiometric ratios. More than 60% of the hydrogen contained in CH3OH can be converted to molecular hydrogen at 500?C with a ratio of N2O/CH3OH not greater than 0.6 and with a contact time of reactants with the catalyst of approx. 6 seconds.

Nickel-catalysed gasification of brown coal in a fluidized bed reactor at atmospheric pressure

Fuel ◽  
1985 ◽  
Vol 64 (6) ◽  
pp. 795-800 ◽  
Author(s):  
A TOMITA ◽  
Y WATANABE ◽  
T TAKARADA ◽  
Y OHTSUKA ◽  
Y TAMAI
Keyword(s):  
Fluidized Bed ◽  
Brown Coal ◽  
Atmospheric Pressure ◽  
Fluidized Bed Reactor
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