Modeling of gas-phase heterogeneous photocatalytic oxidation reactor in the presence of mass transfer limitation and axial dispersion

2020 ◽  
Vol 386 ◽  
pp. 124013 ◽  
Author(s):  
Mojtaba Malayeri ◽  
Chang-Seo Lee ◽  
Fariborz Haghighat ◽  
Lubomir Klimes
Keyword(s):  
Mass Transfer ◽  
Gas Phase ◽  
Photocatalytic Oxidation ◽  
Axial Dispersion ◽  
Mass Transfer Limitation ◽  
Oxidation Reactor

Hydrodynamic and gas phase axial dispersion in an air-molten salt two-phase system (molten salt oxidation reactor)

2005 ◽  
Vol 44 (10) ◽  
pp. 1054-1062 ◽  
Author(s):  
Yong-Jun Cho ◽  
Hee-Chul Yang ◽  
Hee-Chul Eun ◽  
Jae-Hyung Yoo ◽  
Joon-Hyung Kim
Keyword(s):  
Molten Salt ◽  
Gas Phase ◽  
Axial Dispersion ◽  
Phase System ◽  
Two Phase ◽  
Oxidation Reactor

Biofilm structure and mass transfer in a gas phase trickle-bed biofilter

2001 ◽  
Vol 43 (1) ◽  
pp. 285-293 ◽  
Author(s):  
X. Zhu ◽  
M. T. Suidan ◽  
C. Alonso ◽  
T. Yu ◽  
B. J. Kim ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Gas Phase ◽  
Transfer Resistance ◽  
Mass Transfer Limitation ◽  
Gas Treatment ◽  
Oxygen Penetration ◽  
Waste Gas Treatment ◽  
Liquid Mass Transfer ◽  
Trickle Bed ◽  
Biofilm Structure

Mass transport phenomena occurring in the biofilms of gas phase trickle-bed biofilters are investigated in this study. The effect of biofilm structure on mass transfer mechanisms is examined using experimental observation from the operating of biofilters, microelectrode techniques and microscopic examination. Since the biofilms of biofilters used for waste gas treatment are not completely saturated with water, there is not a distinguishable liquid layer outside the biofilm. Results suggest that due to this characteristic, gas phase substrates (such as oxygen or volatile organic compounds) may not be limited by the aqueous phase because transport of the compound into the biofilm can occur directly through non-wetted areas. On the other hand, for substrates that are present only in the liquid phase, such as nitrate, the mass transfer limitation is more serious because of the limited liquid supply. Microscopic observations show that a layered structure with void spaces exists within the biofilm. Oxygenconcentration distributions along the depth of the biofilms are examined using an oxygen microelectrode. Results indicate that there are some high dissolved oxygen zones inside the biofilm, which suggests the existence of passages for oxygen transfer into the deeper sections of the biofilm in a gas phase trickle-bed biofilter. Both the low gas-liquid mass transfer resistance and the resulting internal structure contribute to the high oxygen penetration within the biofilms in gas phase trickle-bed biofilters.

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.

Photocatalytic oxidation of gas-phase Hg0 by Fe-doped TiO2 hollow microspheres

2021 ◽  
Vol 291 ◽  
pp. 129538
Author(s):  
Zhaopeng Zhang ◽  
Xian Li ◽  
Dayong Guan ◽  
Yingchao Gao ◽  
Jiang Wu ◽  
...  
Keyword(s):  
Gas Phase ◽  
Photocatalytic Oxidation ◽  
Hollow Microspheres ◽  
Doped Tio2

Gas-phase photocatalytic oxidation of NO over palladium modified TiO2 catalysts

2008 ◽  
Vol 9 (9) ◽  
pp. 1941-1944 ◽  
Author(s):  
Zhongyi Sheng ◽  
Zhongbiao Wu ◽  
Yue Liu ◽  
Haiqiang Wang
Keyword(s):  
Gas Phase ◽  
Photocatalytic Oxidation ◽  
Oxidation Of No

TiO2 deactivation during the gas-phase photocatalytic oxidation of dimethyl sulfide

2004 ◽  
Vol 52 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Nuria González-Garcı́a ◽  
José A Ayllón ◽  
Xavier Doménech ◽  
José Peral
Keyword(s):  
Gas Phase ◽  
Photocatalytic Oxidation ◽  
Dimethyl Sulfide
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