Modeling of catalytic ozonation process in a three-phase reactor

Erol, Funda
Oezbelge, Tuelay A.
Oezbelge, H. Oender
In this research, the main objective was to determine the flow characteristics of a three-phase reactor in order to use this knowledge in the modeling of catalytic ozonation of aqueous dye solutions. Therefore, the stimulus-response method was used in the tracer experiments; thus, the degree of liquid mixing in the reactor was estimated by means of residence time distribution, Peclet number and axial dispersion coefficient in the presence and the absence of the catalyst. Experimental data were obtained by performing the catalytic ozonation of aqueous Acid Red-151 (AR-151) and Remazol Brilliant Blue-R (RBBR) dye solutions, in the presence of perfluorinated-octyl-alumina (PFOA) catalyst particles at different operating conditions. The chemical oxygen demand (COD), the dye and ozone concentrations in the liquid phase were measured at the steady state along the height of the column reactor and at the exit. According to the results, it was observed that the gas-liquid reactor without the catalyst particles showed a hydrodynamic behavior equivalent to two or three completely stirred tank reactors (CSTRs) in-series for the conventional ozonation process. The presence of catalyst particles caused the flow behavior of the three phase reactor to approach to one CSTR or two CSTRs in-series depending on the gas and liquid flow rates so that the modeling of the catalytic ozonation process was done satisfactorily on that basis. The modeling results showed satisfactory agreement with the experimental ones in the prediction of outlet dye and dissolved ozone concentrations from the reactor, especially at relatively high gas velocities (Q(G) = 150 and 200 L h(-1)) for AR-151, where the dissolved ozone concentration was not limited. However, the discrepancy was about 15% between the theory and experiment at the lower gas flow rates due to the limited ozone concentrations with respect to the dye concentrations at the high inlet dye concentration of AR-151 (C-D,C-i = 100 mg L-1). For RBBR, the predicted and experimental values were very close to each other since ozone limitation or dye abundance was not realized in these experiments.


Assessment of diffusive and convective mechanisms during carbon dioxide sequestration into deep saline aquifers
Özgür, Emre; Gümrah, Fevzi; Department of Petroleum and Natural Gas Engineering (2006)
The analytical and numerical modeling of CO2 sequestration in deep saline aquifers having different properties was studied with diffusion and convection mechanisms. The complete dissolution of CO2 in the aquifer by diffusion took thousands, even millions of years. In diffusion dominated system, an aquifer with 100 m thickness saturated with CO2 after 10,000,000 years. It was much earlier in convective dominant system. In diffusion process, the dissolution of CO2 in aquifer increased with porosity increase; ...
Comparison of anaerobic acrylic acid biotransformation in single- and two-stage pH-stat completely stirred tank reactor systems
Demirer, Göksel Niyazi; Speece, RE (Wiley, 2000-01-01)
Performance of single- and two-stage pH-stat completely stirred tank reactor (CSTR) systems for anaerobic acrylic acid biotransformation was investigated and compared. In the experiments, acetate was added with acrylic acid. Acetate concentration in both single- and two-stage reactors was continuously maintained at a nonlimiting concentration of 2000 +/- 200 mg/L. using a computer-controlled pH-stat system to allow observation of the effect of acrylate biotransformation on the more sensitive methanogenic st...
Comparison of iscst3 and aermod air dispersion models: case study of cayirhan thermal power plant
Dölek, Emre; Atımtay, Aysel; Department of Environmental Engineering (2007)
In this study, emission inventory was prepared and pollutant dispersion studies were carried out for the area around Çayırhan Thermal Power Plant to determine the effects of the plant on the environment. Stack gas measurement results were used for the emissions from the power plant and emission factors were used for calculating the emissions from residential sources and coal stockpiles in the study region. Ground level concentrations of SO2, NOx and PM10 were estimated by using EPA approved dispersion model...
Enhancement of biodegradability by continuous ozonation in Acid Red-151 solutions and kinetic modeling
Gokcen, F; Ozbelge, TA (Elsevier BV, 2005-11-15)
In this work, continuous ozonation of aqueous Acid Red-151 was performed in a stirred tank reactor at neutral pH and 25 degrees C. The results show that ozonation is capable of a rapid conversion of the Acid Red-151 dye molecule to more biodegradable intermediates up to the ozonation time of 120 min at which the optimum BOD5/COD ratio is obtained. The peak BOD5/COD ratios were found to be in the range of 0.028-0.35 for the initial dye concentrations being in the range of 1000-100 mg/L, respectively.
A kinetic study on the decolorization of aqueous solutions of acid Red-151 by ozonation
Ozbelge, TA; Erol, F; Ozbelge, O (Informa UK Limited, 2003-01-01)
The ozonation kinetics of an azo dye, namely, Acid Red-151 was investigated. Effects of pH, initial ozone, and initial dye concentrations on the ozonation of the dye were studied. The reaction orders were found to be one with respect to both ozone and dye concentrations for the studied pH range of 2.5-10. The reaction rate constants were obtained as 125.8, 95.4, 87.9, and 129.9 L mmol(-1) min(-1) at the pH values of 2.5, 5, 7, and 10, respectively. The initial ozonation rate decreased with the increasing pH...
Citation Formats
F. Erol, T. A. Oezbelge, and H. O. Oezbelge, “Modeling of catalytic ozonation process in a three-phase reactor,” JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING, pp. 295–306, 2009, Accessed: 00, 2020. [Online]. Available: