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Light intensity distribution in heterogenous photocatalytic reactors
Author(s) -
Pareek Vishnu,
Chong Siewhui,
Tadé Moses,
Adesina Adesoji A.
Publication year - 2008
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.129
Subject(s) - monte carlo method , intensity (physics) , light intensity , boundary value problem , fluent , materials science , photon , radiant intensity , photocatalysis , mechanics , boundary (topology) , optics , physics , computational physics , computational fluid dynamics , radiation , chemistry , mathematics , catalysis , mathematical analysis , statistics , biochemistry , quantum mechanics
In this paper, we have discussed the state of the art on numerical techniques for estimating light intensity distribution in photocatalytic reactors. After giving a brief introduction to various photocatalytic reactor designs, a detailed derivation of the radiation transport equation (RTE) has been presented. The RTE is an integrodifferential equation and needs appropriate boundary conditions and optical properties of the medium. To provide a boundary condition for the light emitted from the radiation sources, a number of lamp source models have been described. Different approaches for the numerical simulation of the RTE have been presented with special emphasis on the Monte Carlo and finite volume (or discrete ordinate) approaches. In the Monte Carlo approach, the reaction space was divided into small cubical cells. The path of a photon was traced using a stochastic approach. A conservative variant of the discrete ordinate model available in FLUENT was used to assess the effect of wall reflectivity, catalyst loading, and phase function parameter on the light intensity distribution. For relatively low catalyst loadings, the wall reflectivity strongly influenced the light intensity distribution. However, for an optically thick medium, the wall reflectivity had very little or no effect. The volume‐averaged light intensity distribution decreased rather sharply with the catalyst loading and an opposite trend was obtained for LVREA. Finally, a semiempirical kinetic model was presented to evaluate the rate of reaction and conversion of a photoreactor using the computational fluid dynamics (CFD) approach. Model verification was carried out using experimental data for photodegradation of Bayer liquor. A correlation coefficient of 0.974 between simulated and experimental results indicated that the proposed model was adequate. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.