A Simple Kinetic Model for the Simultaneous Concentration and Intensity Dependencies of TCE Photocatalyzed Destruction

1998 ◽  
Vol 3 (2) ◽  
Author(s):  
Santosh Upadhya ◽  
David F. Ollis
Keyword(s):  
Simple Model ◽  
Kinetic Model ◽  
Light Intensity ◽  
Reaction Rate ◽  
Air Purification ◽  
Intensity Dependence ◽  
Reactant Concentration ◽  
Upper Limit ◽  
Wide Range ◽  
Simple Kinetic Model

AbstractTrichloroethylene conversion in gas-solid photocatalysis ranks as one of the fastest reactions for air purification and treatment. The development of a complete kinetic model for this conversion is important in that it represents, under some conditions, a likely upper limit to conversion photoefficiency. Both reactant concentration and light intensity are known to influence reaction rate, but only two literature reports have explored a sufficiently wide range of concentrations to find that the intensity dependence is coupled to, and not independent of, the reactant concentration. We develop here a simple model which rationalizes this experimental behavior based upon the familiar competition between species for photo-produced holes (h

A Kinetic Model of the Accommodation Pumping Phenomenon

1974 ◽  
Vol 52 (11) ◽  
pp. 2073-2076 ◽  
Author(s):  
Graham Richard Branton ◽  
Stephen Alan Ryce
Keyword(s):  
Kinetic Model ◽  
Temperature Difference ◽  
Specular Reflection ◽  
Real Situation ◽  
Thermal Transpiration ◽  
Upper Limit ◽  
Simple Kinetic Model ◽  
The Ideal

A simple kinetic model of the accommodation pumping phenomenon is developed. This model is consistent with the earlier suggestion that the extent to which specular reflection occurs from smooth Pyrex surfaces is dependent upon the velocity of the atoms. It is shown that the upper limit for the pump ratio (PA/PB) is 2, but that in any real situation this ratio would be less than this value. The model is used to show that the deviation of the thermal transpiration ratio from the ideal value, (T1/T2)1/2, should be the same as the accommodation pumping ratio for the same tubing with the same temperature difference.

Optimization of Reduced Kinetic Models for Reactive Flow Simulations

2013 ◽  
Author(s):  
P. Gokulakrishnan ◽  
R. Joklik ◽  
D. Viehe ◽  
A. Trettel ◽  
E. Gonzalez-Juez ◽  
...  
Keyword(s):  
Parameter Estimation ◽  
Kinetic Model ◽  
Kinetic Models ◽  
Reaction Rate ◽  
Reactive Flow ◽  
Generation Process ◽  
Detailed Model ◽  
Flow Simulations ◽  
Wide Range ◽  
Target Data

A robust optimization scheme, known as rkmGen, for reaction rate parameter estimation has been developed for the generation of reduced kinetics models of practical interest for reactive flow simulations. It employs a stochastic optimization algorithm known as Simulated Annealing, and is implemented in C++ and coupled with Cantera, a chemical kinetics software package, to automate the reduced kinetic mechanism generation process. Reaction rate parameters in reduced order models can be estimated by optimizing against target data generated from a detailed model or by experiment. Target data may be of several different kinds: ignition delay time, blow-out time, laminar flame speed, species time-history profiles and species reactivity profiles. The software allows for simultaneous optimization against multiple target data sets over a wide range of temperatures, pressures and equivalence ratios. In this paper, a detailed description of the optimization strategy used for the reaction parameter estimation is provided. To illustrate the performance of the software for reduced kinetic development, a number of test cases for various fuels were used: one-step, three-step and four-step global reduced kinetic models for ethylene, Jet-A and methane, respectively, and a fifty-step semi-global reduced kinetic model for methane. The fifty-step semi-global reduced kinetic model was implemented in the Star*CCM+ commercial CFD code to simulate Sandia Flame D using laminar flamelet libraries and compared with the experimental data. Simulations were also performed with the GRI3.0 mechanism for comparisons.

scholarly journals Synergistic Effect of Nanophotocatalysis and Nonthermal Plasma on the Removal of Indoor HCHO

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yuanwei Lu ◽  
Dinghui Wang ◽  
Yuting Wu ◽  
Chongfang Ma ◽  
Xingjuan Zhang ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Indoor Air ◽  
Photocatalytic Oxidation ◽  
Reaction Rate ◽  
Nonthermal Plasma ◽  
Pollutant Removal ◽  
Pollutant Concentration ◽  
Air Purification ◽  
Plate Electrode ◽  
Air Treatment

Photocatalysis is an effective method of air purification at the condition of a higher pollutant concentration. However, its wide application in indoor air cleaning is limited due to the low level of indoor air contaminants. Immobilizing the nanosized TiO2particles on the surface of activated carbon filter (TiO2/AC film) could increase the photocatalytic reaction rate as a local high pollutant concentration can be formed on the surface of TiO2by the adsorption of AC. However, the pollutant removal still decreased quickly with the increase in flow velocity, which results in a decrease in air treatment capacity. In order to improve the air treatment capacity by the photocatalytic oxidation (PCO) method, this paper used formaldehyde (HCHO) as a contaminant to study the effect of combination of PCO with nonthermal plasma technology (NTP) on the removal of HCHO. The experimental results show that HCHO removal is more effective with line-to-plate electrode discharge reactor; the HCHO removal and the reaction rate can be enhanced and the amount of air that needs to be cleaned can be improved. Meanwhile, the results show that there is the synergistic effect on the indoor air purification by the combination of PCO with NTP.

Hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate

1989 ◽  
Vol 67 (5) ◽  
pp. 857-861 ◽  
Author(s):  
Shin-Ichi Miyamoto ◽  
Tetsuo Sakka ◽  
Matae Iwasaki
Keyword(s):  
Kinetic Model ◽  
Exchange Reaction ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Hydrogen Adsorption ◽  
Platinum Catalyst ◽  
Isotope Exchange Reaction ◽  
Hydrogen Isotope Exchange ◽  
Supported Platinum

The reaction rate of hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate is studied. The exchange reaction is described with the kinetic model which is the modification of that for the exchange reaction catalyzed by alumina-supported platinum catalyst. For the comparison of experimental results with this model relative amount of the number of sites for hydrogen adsorption was estimated from the initial rate of hydrogen isotope exchange between H2 and D2 on the same surface. The results show that the kinetic model is applicable for the plate catalyst if the number of the sites for hydrogen absorption, which is very sensitive to the surface state of the catalyst, was estimated not from the macroscopic surface area but from our scheme. Keywords: hydrogen isotope exchange reaction, platinum plate as catalyst.

Light-Intensity Dependence In The Kinetics Of N-Gap Photoelectrode Stabilization

2010 ◽  
Vol 89 (3) ◽  
pp. 181-186 ◽  
Author(s):  
F. van Overmeire ◽  
F. Vanden Kerchove ◽  
W. P. Gomes ◽  
F. Cardon
Keyword(s):  
Light Intensity ◽  
Intensity Dependence ◽  
Kinetics Of
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