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Author |
Roegiers, J.; Denys, S. |
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Title |
Development of a novel type activated carbon fiber filter for indoor air purification |
Type |
A1 Journal article |
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Year  |
2021 |
Publication |
Chemical Engineering Journal |
Abbreviated Journal |
Chem Eng J |
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Volume |
417 |
Issue |
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Pages |
128109 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
A novel type of activated carbon fiber filter was developed for indoor air purification. The filter is equipped with electrodes for thermo-electrical regeneration at the point of saturation. The electrodes are arranged in such a way that the filter forms a pleated structure with an electrode in the tip of each pleat. This allows for a uniform temperature distribution on the filter surface during the regeneration process and the pleated structure reduces the overall pressure drop across the filter. The latter was validated by Computational Fluid Dynamics, using Darcy-Forchheimer parameters derived in previous work. The CFD model was further used to perform a virtual sensitivity study in search for the optimal ACF filter design by varying the pleat length, pleat height and filter thickness. Finally, adsorption and desorption properties were investigated with acetaldehyde and toluene as model compounds. Freundlich and Langmuir adsorption parameters, derived in previous work were successfully validated with a Multiphysics model. |
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Wos |
000653229500132 |
Publication Date |
2020-12-15 |
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ISSN |
1385-8947; 1873-3212 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.216 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 6.216 |
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Call Number |
UA @ admin @ c:irua:174105 |
Serial |
7800 |
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Author |
Roegiers, J. |
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Title |
Development of combined photocatalytic and active carbon fiber technology for indoor air purification based on Multiphysics models |
Type |
Doctoral thesis |
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Year |
2021 |
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Issue |
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Pages |
XXX, 197 p. |
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Keywords |
Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Exposure to volatile organic compounds (VOCs) remains a major public health concern. Indoor VOC concentrations typically far exceed outdoor levels due to a variety of emission sources and the stringent insulation measures that are imposed today. Many attempts have been made to use photocatalysis for indoor air purification. In an ideal situation, photocatalysis is capable of complete mineralization of VOCs to H2O and CO2, without any byproduct formation. Moreover, the process can take place at standard atmospheric conditions, i.e. ambient temperature and atmospheric pressure. However, successful exploitation is still impeded due to low conversion efficiency, significant pressure loss (and hence a high energy consumption) and byproduct formation. In the first part of this thesis an attempt was made to tackles these problems by designing a novel type of photocatalytic (PCO) reactor. The PCO device consists of a cylindrical vessel filled with TiO2-coated glass tubes and equipped with UV fluorescence lamps. It was investigated in terms of fluid dynamics, coating properties, UV-light distribution and photocatalytic activity. Experimental data was later used to develop and calibrate a Multiphysics model. The model proved to be a useful tool for designing and upscaling the PCO reactor. Consequently, an optimized prototype reactor was constructed and tested according the CEN-EN-16846-1 standard for VOC removal. Although the prototype showed promising results for lab-scale conditions, it struggled with byproduct formation when purifying ppb-level VOCs. In the second part of this thesis, activated carbon adsorption was investigated in order to combine it with photocatalysis. Activated carbon fiber was opted for its fast kinetics, high adsorption capacity and thermo-electrical regeneration. The filter was studied in detail regarding the adsorption of polar and apolar VOCs at indoor air concentration levels and regeneration capabilities. Experimental data was used to develop a Multiphysics model for activated carbon adsorption as well. Consequently, a novel type of ACF filter was developed using the Multiphysics model, which was equipped with electrodes in the tips of the pleats for effective thermal regeneration. In the last part, the combination of both ACF and PCO was studied using a realistic case study. Based on the Multiphysics model, the feasibility of a so-called hybrid air purification device could be investigated. The Multiphysics model shows promising results for this hybrid PCO-ACF system and hence, a demo setup was constructed for future research. |
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Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:181137 |
Serial |
6860 |
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Author |
van Walsem, J.; Roegiers, J.; Modde, B.; Lenaerts, S.; Denys, S. |
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Title |
Proof of concept of an upscaled photocatalytic multi-tube reactor : a combined modelling and experimental study |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Chemical engineering journal |
Abbreviated Journal |
Chem Eng J |
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Volume |
378 |
Issue |
378 |
Pages |
122038 |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Three upscaled multi-tube photocatalytic reactors designed for integration into HVAC (Heating, Ventilation and Air Conditioning) systems were proposed and evaluated using a CFD modelling approach, with emphasis on the flow, irradiation and concentration distribution in the reactor and hence, photocatalytic performance. Based on the obtained insights, the best reactor design was selected, further characterized and improved by an additional proof of concept study and eventually converted into practice. Subsequently, the scaled-up prototype was experimentally tested according to the CEN-EN-16846-1 standard (2017) for volatile organic compound (VOC) removal by an external scientific research center. The combined modelling and experimental approach used in this work, leads to essential insights into the design and assessment of photocatalytic reactors. Therefore, this study provides an essential step towards the optimization and commercialization of photocatalytic reactors for HVAC applications. |
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Wos |
000487764800011 |
Publication Date |
2019-06-22 |
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Series Volume |
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Edition |
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ISSN |
1385-8947; 1873-3212 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.216 |
Times cited |
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Open Access |
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Notes |
; J.V.W. acknowledges the Agentschap Innoveren & Ondernemen for a PhD fellowship. ; |
Approved |
Most recent IF: 6.216 |
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Call Number |
UA @ admin @ c:irua:162190 |
Serial |
5986 |
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Author |
Shi, X.; Ronsse, F.; Roegiers, J.; Pieters, J.G. |
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Title |
3D Eulerian-Eulerian modeling of a screw reactor for biomass thermochemical conversion. Part 1: solids flow dynamics and back-mixing |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Renewable energy |
Abbreviated Journal |
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Volume |
143 |
Issue |
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Pages |
1465-1476 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Three-dimensional (3D) computational fluid dynamics (CFD) simulations were performed to study solids flow dynamics and solids back-mixing behavior in a screw reactor (designed for thermal conversion of dry biomass particles) based on the Eulerian-Eulerian method. Simulation results were compared against experimental data with respect to filling degree and mean residence time of particles. The mean deviations for filling degree and for mean residence time between simulation and experiment were about 0.01 and 11.4 s, respectively, which shows that the model is reasonably accurate in predicting solids flow behavior in the screw reactor. The solids flow dynamics inside the reactor were discussed. The solids residence time distribution (RTD) was calculated and the degree of solids back-mixing in the forward transportation direction of the reactor was analyzed. It was found that solids being flung over the shaft and solids back-leakage, resulting from the low solids forward transportation velocity at the clearance between the flight and the bottom shell of the screw reactor, were responsible for solids back-mixing. The degree of solids back-mixing can be reduced at higher screw rotating speeds when keeping inlet mass flow rate of solids constant. (C) 2019 Elsevier Ltd. All rights reserved. |
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Wos |
000482686100039 |
Publication Date |
2019-05-28 |
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Series Issue |
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Edition |
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ISSN |
0960-1481 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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no |
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Call Number |
UA @ admin @ c:irua:162757 |
Serial |
7384 |
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Author |
Roegiers, J.; Denys, S. |
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Title |
CFD-modelling of activated carbon fibers for indoor air purification |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Chemical engineering journal |
Abbreviated Journal |
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Volume |
365 |
Issue |
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Pages |
80-87 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Activated carbon fibers for indoor air purification were investigated by means of pressure drop and adsorption capacity. The Darcy-Forchheimer law combined with Computational Fluid Dynamics (CFD) modelling was deployed to simulate the pressure drop over an activated carbon fiber (ACF) filter with varying filter thickness. The CFD model was later combined with adsorption modelling to simulate breakthrough profiles of acetaldehyde adsorption on the ACF-filter. The adsorption model incorporates mass transfer resistance and adsorption equilibrium. It assumes local equilibrium between gas phase and solid phase. The latter was investigated for three different adsorption isotherms: linear, Langmuir and Freundlich adsorption. Successful agreement between model simulations and experimental data was obtained, using the Freundlich adsorption model. The numerical model could provide valuable insights and allows to continuously improve the design of filtration devices. |
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Wos |
000459009800009 |
Publication Date |
2019-02-02 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1385-8947; 1873-3212 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:156996 |
Serial |
7590 |
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Author |
van Walsem, J.; Roegiers, J.; Modde, B.; Lenaerts, S.; Denys, S. |
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Title |
Determination of intrinsic kinetic parameters in photocatalytic multi-tube reactors by combining the NTUm-method with radiation field modelling |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Chemical engineering journal |
Abbreviated Journal |
Chem Eng J |
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Volume |
354 |
Issue |
354 |
Pages |
1042-1049 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
In this work, we propose an adapted Number of Transfer Units (NTUm)-method as an effective tool to determine the Langmuir-Hinshelwood kinetic parameters for a photocatalytic multi-tube reactor. The Langmuir-Hinshelwood rate constant kLH and the Langmuir adsorption constant KL were determined from several experiments under different UV-irradiance conditions, resulting in irradiance depending values for kLH. In order to determine a unique, intrinsic empirical constant k0, valid for all irradiation conditions, we coupled the adapted NTUm-method with a radiation field model to predict UV-irradiance distribution inside the reactor. The final set of kinetic parameters were derived using a Generalized Reduced Gradient (GRG) nonlinear solving method in Matlab which minimizes the differences between model and experimental reactor outlet concentrations of acetaldehyde for various photocatalytic experiments under varying operating conditions, including inlet concentration, flow rate and UV-irradiance. An excellent agreement of the intrinsic empirical constant k0, derived from the coupled NTUm-radiation field model and an earlier published CFD approach was found, emphasizing its validity and reliability. |
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Wos |
000445413900099 |
Publication Date |
2018-08-03 |
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ISSN |
1385-8947; 1873-3212 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.216 |
Times cited |
2 |
Open Access |
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Notes |
; J.V.W. acknowledges the Agentschap Innoveren & Ondernemen for a PhD fellowship. ; |
Approved |
Most recent IF: 6.216 |
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Call Number |
UA @ admin @ c:irua:154845 |
Serial |
5940 |
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Author |
van Walsem, J.; Roegiers, J.; Modde, B.; Lenaerts, S.; Denys, S. |
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Title |
Integration of a photocatalytic multi-tube reactor for indoor air purification in HVAC systems : a feasibility study |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Environmental Science and Pollution Research |
Abbreviated Journal |
Environ Sci Pollut R |
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Volume |
25 |
Issue |
18 |
Pages |
18015-18026 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
This work is focused on an in-depth experimental characterization of multi-tube reactors for indoor air purification integrated in ventilation systems. Glass tubes were selected as an excellent photocatalyst substrate to meet the challenging requirements of the operating conditions in a ventilation system in which high flow rates are typical. Glass tubes show a low-pressure drop which reduces the energy demand of the ventilator, and additionally, they provide a large exposed surface area to allow interaction between indoor air contaminants and the photocatalyst. Furthermore, the performance of a range of P25-loaded sol-gel coatings was investigated, based on their adhesion properties and photocatalytic activities. Moreover, the UV light transmission and photocatalytic reactor performance under various operating conditions were studied. These results provide vital insights for the further development and scaling up of multi-tube reactors in ventilation systems which can provide a better comfort, improved air quality in indoor environments, and reduced human exposure to harmful pollutants. |
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Wos |
000436879200071 |
Publication Date |
2018-04-24 |
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Abbreviated Series Title |
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Edition |
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ISSN |
0944-1344; 1614-7499 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.741 |
Times cited |
3 |
Open Access |
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Notes |
; J.V.W. acknowledges the Agentschap Innoveren and Ondernemen for a PhD fellowship. ; |
Approved |
Most recent IF: 2.741 |
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Call Number |
UA @ admin @ c:irua:150946 |
Serial |
5967 |
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Author |
Roegiers, J.; van Walsem, J.; Denys, S. |
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Title |
CFD- and radiation field modeling of a gas phase photocatalytic multi-tube reactor |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Chemical engineering journal |
Abbreviated Journal |
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Volume |
338 |
Issue |
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Pages |
287-299 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
This paper focusses on the development of a Multiphysics model as a tool for assessing the performance of a multi-tube photoreactor. The model predicts the transient behavior of acetaldehyde concentration, as a model compound for the organic fraction of the indoor air pollutants, under varying sets of conditions. A 3D-model couples radiation field modeling with reaction kinetics and fluid dynamics in order to simulate the transport of the pollutant as it progresses through the reactor. A model-based approach is proposed to determine the layer thickness and refractive index of different P25-powder modified solgel coatings, using an optimization procedure to estimate these parameters based on UV-irradiance measurements. The radiation field model was able to accurately predict the irradiance on the catalytic surface within the reactor. Consequently, the radiation field model was used to define an irradiance dependent reaction rate constant in a coupled Multiphysics model. An optimization routine was deployed to estimate the adsorption, desorption- and photocatalytic reaction rate constants on the TiO2-surface, using experimentally determined, transient outlet concentrations of acetaldehyde. Additionally, a validation test was performed in an air-tight climate chamber at much higher flow rates, higher irradiance and realistic indoor pollutant concentrations to emphasize the reliability and accuracy of the parameters for adsorption, desorption and photocatalytic reaction. The developed model makes it possible to optimize the reactor design and scale-up for commercial applications. |
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Wos |
000427618400031 |
Publication Date |
2018-01-08 |
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Edition |
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ISSN |
1385-8947; 1873-3212 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:149115 |
Serial |
7589 |
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