scholarly journals Photocatalytic Degradation of Toluene in Air Using a Fluidized Bed Photoreactor

2007 ◽  
Vol 2007 ◽  
pp. 1-8 ◽  
Author(s):  
O. Prieto ◽  
J. Fermoso ◽  
R. Irusta
Keyword(s):  
Mass Transfer ◽  
Photocatalytic Degradation ◽  
Fluidized Bed ◽  
Particle Surface ◽  
Methanol Solution ◽  
Transfer Coefficients ◽  
Photocatalytic Reactor ◽  
Degussa P25 ◽  
Ft Ir ◽  
Regeneration Processes

The photocatalytic degradation of toluene in air was carried out on particles ofTiO2in a photocatalytic reactor that had been developed to study the treatment of organic pollutants in a gaseous phase. Hypothetically, the fluidized bed technology of this reactor could make it possible to increase the mass transfer coefficients in comparison with those of conventional photoreactors. The photocatalytic particles used were prepared by mixingTiO2(Degussa P25) and starch in a methanol solution. The XRD and SEM results of these aggregates confirm the titanium dioxide (Degussa P25) characteristics, such as the presence of anatase on the particle surface and spongy and wrinkled morphology. Toluene concentrations varied from 0.9 to 199ppmv, and all the experiments were carried out with a flow rate of 300 NL/h. Toluene conversions from 77%to 100%were obtained in the range studied. In this work, the regeneration processes of deactivatedTiO2photocatalysts have been investigated using FT-IR and GC/MS techniques. Benzoic acid, benzaldehyde, and benzyl alcohol were the three major intermediate products identified.

Photocatalytic degradation intrinsic kinetics of gaseous cyclohexane in a fluidized bed photocatalytic reactor

2012 ◽  
Vol 39 (4) ◽  
pp. 1711-1726 ◽  
Author(s):  
Qijin Geng ◽  
Qingming Wang ◽  
Yunchen Zhang ◽  
Lintong Wang ◽  
Huiqin Wang
Keyword(s):  
Photocatalytic Degradation ◽  
Fluidized Bed ◽  
Photocatalytic Reactor ◽  
Intrinsic Kinetics ◽  
Kinetics Of

scholarly journals Gas solid contacting measurements in a turbulent fluidized bed by oxidation of carbon monoxide

2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1413-1423
Author(s):  
Robbie Venderbosch ◽  
Wolter Prins ◽  
Swaaij van
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Phase Model ◽  
Internal Diameter ◽  
Turbulent Regime ◽  
Dense Phase ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Fluid Bed ◽  
Real Flow

The conversion rate of the mass transfer controlled oxidation of CO over a Pt/?-alumina catalyst (d = 65 ?m) has been studied in a fluidized bed (internal diameter = 0.05 m) p operated close to and in the turbulent fluid bed regime. The objectives were to investigate the gas-solids contacting efficiency to evaluate the conversion data in terms of overall mass transfer coefficients and define the apparent contact efficiency. At high superficial gas velocities, the concept of formation of particle agglomerates and voids is more realistic than the two-phase model considering discrete bubbles and a dense phase. The two-phase model is not useless but has hardly any relation with the real flow pattern in the turbulent regime.

CFD Simulation of Mass Transfer around Spherical Particles in Fluidized Bed

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Zoha Vatani ◽  
Majid Taghizadeh ◽  
Reza Orouj
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Spherical Particles ◽  
Vapor Concentration ◽  
Transfer Coefficients ◽  
Air Velocity ◽  
Nusselt Numbers ◽  
Wet Particles

In this study, the mass transfer of three-dimensional nonreactive gas-solid fluidized bed was investigated computationally. The influence of the inlet gas velocity and temperature on mass transfer of air to wet particles was analyzed. The simulation results indicated that the mass transfer coefficients of air to spherical sand particles was decreased from 2.12 to 1.66 m/s with increment of temperature from 300 to 360 K. Sherwood numbers of gas to cluster increased with the increase of inlet air velocity. CFD model of the gas-particle heat transfer have been implemented, the result showed that the heat flux of gas to particles increased with the increase of Reynolds number. Distributions of water vapor concentration and velocity in this bed were numerically predicted and the computed Sherwood and Nusselt numbers were compared with the estimated values from empirical equations.

Heat and Mass Transfer of Drying Particles in a Fluidized Bed

2010 ◽  
Author(s):  
J. Bruchmu¨ller ◽  
B. G. M. van Wachem ◽  
S. Gu ◽  
K. H. Luo
Keyword(s):  
Mass Transfer ◽  
Moisture Content ◽  
Heat And Mass Transfer ◽  
Fluidized Bed ◽  
Particle Temperature ◽  
Mixing Efficiency ◽  
Coffee Bean ◽  
Transfer Coefficients ◽  
Quality Properties ◽  
On Line

In this study, the heat transfer and drying process of arabica coffee beans in a batch fluidized bed roaster has been studied. Herein, the discrete element method (DEM) has been used and modified to account for resolved 1D temperature and moisture content profiles within each single coffee bean. This approach has the strength to provide much more information on the global (fluidization, mixing) and local (particle data) level compared to existing coffee roaster models. Therefore, the product quality can be evaluated on-line by many more specific criteria beyond the averaged global particle temperature and moisture content. Instead, information of every single particle is available which includes heat and mass transfer coefficients, its local position inside the bed, collision forces, etc. Furthermore, the overall roaster performance is based on e.g. fluidization stability, mixing efficiency or uniformity of quality properties among all particles. More data are presented to account for a broader coffee bean roasting evaluation. Modeling results are in good agreement with experimental data.

scholarly journals Absorption in a three-phase fluidized bed II: Mass transfer investigations

2003 ◽  
Vol 57 (7-8) ◽  
pp. 330-334
Author(s):  
Srdjan Pejanovic ◽  
Radmila Garic-Grulovic ◽  
Predrag Bozalo
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Fluidized Bed ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Interfacial Area ◽  
Transfer Coefficients ◽  
Three Phase

The absorption of carbon dioxide in aqueous diethanolamine solutions was carried out in a three-phase fluidized bed with inert spherical packing. The rate of absorption was calculated on the basis of measuring the concentration change in the liquid phase on-line by a conductivity probe. It was shown that the Danckwerts plot method might be successfully used to simultaneously determine the effective interfacial area and both the gas and liquid-side mass transfer coefficients. While the gas-side mass transfer coefficient is independent of the liquid flow rate, the effective interfacial area and liquid-side mass transfer coefficient increase with increasing liquid flow rate.

Hybrid Modeling of Modified Mathematical Model for Gas Phase Olefine in Fluidized Bed Catalyst Reactors Using Artificial Neural Networks

2009 ◽  
Vol 4 (1) ◽  
Author(s):  
Ahmmed Saadi Ibrehem
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Fluidized Bed ◽  
Hybrid Model ◽  
Operating Conditions ◽  
Transfer Coefficients ◽  
Mass And Heat Transfer ◽  
Artificial Neural

The complex flow patterns induced in fluidized bed catalytic reactors and the competing parameters affecting the mass and heat transfer characteristics makes the design of such reactors a challenging task to accomplish. The models of such a process rely heavily on predictive empirical correlations for mass and heat transfer coefficients. Unfortunately, published empirical based correlations have the common shortcoming of low-prediction efficiency compared with experimental data. In this work, an artificial neural network approach is used to capture the reactor characteristics in terms of heat and mass transfer based on published experimental data. The developed ANN-based heat and mass transfer coefficients relations were used in a conventional FCR model and simulated under industrial operating conditions. The hybrid model predictions of the melt-flow index and the emulsion temperature were compared to industrial measurements as well as published models. The predictive quality of the hybrid model was superior to other models. This modeling approach can be used as an alternative to conventional modeling methods.

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