Simulation of the Light Distribution in a Solar Photocatalytic Bubble Column Reactor Using the Monte Carlo Method

Abstract

Solar illuminated reactors have been used by several researchers for photocatalytic wastewater treatment. In this work, the light distribution in a solar illuminated slurry bubble column reactor was investigated using the Monte Carlo method. The model was validated using total refracted radiation (TRR) measurements at the unilluminated reactor wall. A fairly good agreement between the simulated and experimental TRR measurements was achieved. Bubbles were shown to affect the transmission of direct light much more than that of diffuse light. While the solar diffuse fraction and bubbles strongly affected the TRR at low catalyst loadings, they had a negligible effect on the overall light absorption. The catalyst significantly affected the light distribution with an optimal catalyst loading of 0.15 g/L being deduced from the simulation. An analysis of the local volumetric rate of energy absorption (LVREA) revealed fairly uniform light absorption along the axial direction. The radial LVREA profiles were nonuniform with the region of highest LVREA shifting from the unilluminated side of the reactor at low catalyst loadings to the illuminated side at high catalyst loadings. This study highlighted the rigor, accuracy, and utility of the Monte Carlo method for simulation of the solar light distribution.

Modeling and Simulation of Reaction Environment in Photoredox Catalysis: A Critical Review

“…Another fact that requires further consideration is that photons are not entirely directed to the reaction medium after impinging the system, which directly contributes to the system′s irradiation efficiency. In this sense, Monte Carlo method can be used to solve the RTE solution, probabilistically simulating the possible trajectory of photons in a medium, including absorption, scattering and reflection (Boyjoo et al, 2013;Asadollahfardi et al, 2018;Ayoub, 2020;Akach et al, 2020). This method involves statistical sampling to model complex chemical and physical phenomena and has shown good results when applied to model the radiation field in photochemistry systems (Singh et al, 2007).…”

Computer Simulations of Photocatalytic Reactors

“…Depending on the underlying hypotheses, various versions of the Monte Carlo method can be distinguished [76]. This method is often used to provide simulations of photoreactors [24][25][26][27]. For example, Akach et al performed simulations of the light distribution in a solar photocatalytic bubble column reactor [27].…”

“…This method is often used to provide simulations of photoreactors [24][25][26][27]. For example, Akach et al performed simulations of the light distribution in a solar photocatalytic bubble column reactor [27]. Figure 5 shows the polar plots of LVREA depending on photocatalyst loading.…”

“…This equation depends on the specific geometry of the photocatalytic reactor and the type of light source [22,23]. The RTE solution requires the application of a proper mathematical model, such as the statistical Monte Carlo method [24][25][26][27] or approximation approach-P1 model [28][29][30]. Another important procedure is the discrete ordination method (DOM), which is recognized as an accurate and flexible procedure [19,22,[31][32][33][34][35][36][37][38].…”

“…Polar plots of LVREA at different photocatalyst loadings: (a) 0.005; (b) 0.01; (c) 0.025; (d) 0.05; (e) 0.1; (f) 0.2 g/L. Reprinted with permission from[27]. Copyright American Chemical Society, 2020.…”