scholarly journals Chemical kinetics of hydrogen sulfide selective oxidation in aqueous iron chelates solutions

2013 ◽  
Vol 10 (3) ◽  
pp. 386-394
Keyword(s):  
Chemical Kinetics ◽  
Chemical Reaction ◽  
Bubble Column ◽  
Reaction Rate Constant ◽  
Gas Absorption ◽  
Bubble Column Reactor ◽  
Experimental Conditions ◽  
Absorption Phenomenon ◽  
Ph Range ◽  
Kinetics Of

The present work concerns the investigation of the chemical kinetics of H2S selective oxidation into elemental sulfur, by gas absorption and chemical reaction in Fe3+·(ΝΤΑ) aqueous solutions. By using initial reactivity data, priority is given to the study of intrinsic kinetics i.e. to avoid interactions with ligand degradation and the presence of sulfur. A wetted wall gas-liquid reactor was employed under a batch-recycle regime. The conversion of Fe3+ to Fe2+ chelate was determined over the pH range ca. 3–6, temperature range ca. 30–60°C and a short overall per run contact time of phases. The penetration theory was used for the evaluation of intrinsic reaction rate constant and enhancement factor. Activation energy values determined from the pertinent Arrhenius plots fall in the range, Εa=17.2– 22.8 kcal mol-1. These values compare satisfactorily with the value Εa=24 kcal mol-1 obtained from a similar kinetic study performed in a bubble column reactor and indicates a chemical reaction control of the overall gas absorption phenomenon. Enhancement factors varied in the respective ranges Ε =2.7–7.5 (pH=3), E=3.2–14.1 (pH=4), E=5.9–17.0 (pH=5), και Ε=6.7– 20.1 (pH=6) indicating a substantial increase of the mass transfer coefficient due to chemical reaction. For the experimental conditions applied in this study the following kinetic correlation was validated:

Ozonation of Reactive Blue 81 in the bubble column

2001 ◽  
Vol 44 (5) ◽  
pp. 47-52 ◽  
Author(s):  
S. Ledakowicz ◽  
R. Maciejewska ◽  
J. Perkowski ◽  
A. Bin
Keyword(s):  
Chemical Reaction ◽  
Bubble Column ◽  
Bubble Column Reactor ◽  
Ozone Absorption ◽  
First Order ◽  
Average Value ◽  
Intrinsic Kinetics ◽  
Order Chemical Reaction ◽  
Inner Diameter ◽  
Kinetics Of

The decolourisation process of the Reactive Blue 81 was carried out in a laboratory bubble column reactor with inner diameter 110 mm and working height 550 mm, equipped with a porous glass ozone diffuser (diameter 50 mm). A model of ozone absorption with the chemical reaction in the liquid phase was employed. It was found that the decolourisation proceeds in the fast pseudo first-order regime. The average value of the enhancement factor was calculated from the experimental results and compared with those calculated according to the theory of mass transfer with a second-order chemical reaction. In order to determine the intrinsic kinetics of ozonation, a stopped-flow technique was employed. The rate constant of the dyestuff reaction with ozone was determined as equal to 4.5 × 107 mol/(dm3.s).

scholarly journals Kinetic study of the regeneration of spent caustic via the genetic algorithm method

2018 ◽  
Vol 5 (4) ◽  
pp. 231-229 ◽  
Author(s):  
Asadollah Karimi ◽  
Esmaeil Fatehifar ◽  
Reza Alizadeh ◽  
Hadi Soltani
Keyword(s):  
Genetic Algorithm ◽  
Catalytic Oxidation ◽  
Bubble Column ◽  
Oxygen Demand ◽  
Bubble Column Reactor ◽  
Elementary Model ◽  
Genetic Algorithm Method ◽  
Spent Caustic ◽  
High Chemical Oxygen Demand ◽  
Kinetics Of

Background: Spent caustic contains noxious components such as sulfide species and also high chemical oxygen demand content (COD). Oxidation of these materials to caustic and sulfate species is mostly the rate-controlling step within catalytic oxidation of spent caustic. Methods: In this study, the kinetics of catalytic oxidation of spent caustic and the regeneration methodology of the sulfidic spent caustic were investigated. The kinetics of catalytic oxidation of spent caustic was studied in the presence of a heterogeneous catalyst. The developed mathematical model was verified via the batch bubble column reactor. The elementary and non-elementary models based on the genetic algorithm were used to obtain the rate coefficient and kinetic order. Results: The experiments were carried out at various conditions. The results indicated that the error of objective function of the non-elementary and elementary models was 3.01% and 134.96%, respectively. Conclusion: According to the results, the non-elementary model had rational outcome compared to the elementary one. Also, non-elemental model is more concordance with experimental results.

Ozonation kinetics of winery wastewater in a pilot-scale bubble column reactor

2009 ◽  
Vol 43 (6) ◽  
pp. 1523-1532 ◽  
Author(s):  
Marco S. Lucas ◽  
José A. Peres ◽  
Bing Yan Lan ◽  
Gianluca Li Puma
Keyword(s):  
Bubble Column ◽  
Pilot Scale ◽  
Bubble Column Reactor ◽  
Column Reactor ◽  
Winery Wastewater ◽  
Kinetics Of

Research on Performance of Gas Methyl Iodide Removal

2014 ◽  
Author(s):  
Yanmin Zhou ◽  
Zhongning Sun ◽  
Haifeng Gu ◽  
Junlong Wang ◽  
Zhuang Miao
Keyword(s):  
Removal Efficiency ◽  
Methyl Iodide ◽  
Flow Rate ◽  
Bubble Column ◽  
Gas Absorption ◽  
Bubble Column Reactor ◽  
Absorption Process ◽  
Column Reactor ◽  
System Pressure ◽  
Efficiency Improve

The characteristics of gas methyl iodide removed by containment filter venting system is similar with bubble column reactor, this study is focused on the absorption performance of methyl iodide in a bubble column reactor with experiment and mathematical calculations, the alkalescent sodium thiosulphate solution in a scale-up facility is used as absorber in the research. The results show that the gas methyl iodide removal efficiency is mainly influenced by the temperature of solution, system pressure, gas flow rate and liquid level respectively. In the range of 0∼80°C, the removal efficiency improve obviously with increasing temperature, while the chemical reaction process is a major factor that limiting the removal efficiency, when the temperature is higher than 80°C, the efficiency is no longer sensitive to the variation of temperature and the mass transfer process become the main limiting factors. The increase of system pressure and height of solution can enhance gas absorption process significantly, the removal efficiency improve linearly with the two parameters. However, the gas volume flow rate plays an opposite role on absorption process mainly because of the reducing on contacting time. In addition, the variation of entrance concentration has a little impact on removal efficiency. The mathematical calculations of removal efficiency fit well with experimental results in the bubble column reactor.

Chemical Reaction Effect upon Gas–Liquid Interfacial Area in a Bubble Column Reactor

2013 ◽  
Vol 11 (1) ◽  
pp. 587-593 ◽  
Author(s):  
Antonio Blanco ◽  
Alicia García-Abuín ◽  
Diego Gómez-Díaz ◽  
Jose M. Navaza
Keyword(s):  
Gas Flow ◽  
Bubble Column ◽  
Interfacial Area ◽  
Bubble Column Reactor ◽  
Fast Reaction ◽  
Experimental Conditions ◽  
Column Reactor ◽  
Hydrodynamic Parameters ◽  
State Regime ◽  
Account Due

Abstract This work analyses the influence of different experimental conditions over important hydrodynamic parameters of a bubble column reactor, such as bubble size distribution, gas hold-up and the gas–liquid interfacial area. The influence of gas flow-rate (18–40 L h–1) and reagent concentration (0–0.5 mol L–1) in the liquid phase upon these hydrodynamic parameters have been studied. The influence of experiment time must also be taken into account due to non-steady-state regime. Under these considerations, the chemical absorption rate changes throughout time, and it produces important changes upon the global absorption process, due to modifications in the gas–liquid interfacial area. The presence of a fast reaction in the liquid bulk has the highest influence upon interfacial area.

Ozonation kinetics of cork-processing water in a bubble column reactor

2008 ◽  
Vol 42 (10-11) ◽  
pp. 2473-2482 ◽  
Author(s):  
Bing Yan Lan ◽  
Rinat Nigmatullin ◽  
Gianluca Li Puma
Keyword(s):  
Bubble Column ◽  
Bubble Column Reactor ◽  
Column Reactor ◽  
Processing Water ◽  
Kinetics Of

Kinetics of Microwave-Assisted Reduction of Manganese Oxide

2011 ◽  
Vol 239-242 ◽  
pp. 2286-2292 ◽  
Author(s):  
Hai Chuan Wang ◽  
Zhi You Liao ◽  
Yuan Chi Dong ◽  
Shi Jun Wang ◽  
Yun Zhou
Keyword(s):  
Reaction Time ◽  
Manganese Oxide ◽  
Chemical Reaction ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Microwave Oven ◽  
Microwave Assisted ◽  
Kinetics Of

The reduction rates of manganese oxide by carbon and SiC was examined by heating MnO2-carbon and MnO2-SiC mixtures in a 7-kW industrial microwave oven. The results show that the rate of the reduction increased with the amount of carbon in MnO2-carbon mixture and with SiC in MnO2-SiC mixture. The rate of the MnO2 reduction by carbon was proportional to the reaction time, and that by SiC was proportional to 2/3 power of the reaction time. The reduction was found to be controlled by chemical reaction. The reaction rate constant of the reduction of MnO2kC increased with increasing the amount of carbon in the mixtures but kSiC decreased with increasing the amount of SiC in the mixtures.

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