Determination of global kinetic parameters by optimization procedure using burning velocity measurements

2018 ◽  
Vol 13 (6) ◽  
pp. 50
Author(s):  
Gleb V. Grenkin ◽  
Alexander Yu. Chebotarev ◽  
Valeri I. Babushok ◽  
Sergey S. Minaev
Keyword(s):  
Kinetic Parameters ◽  
Equivalence Ratio ◽  
Reaction Rate ◽  
Functional Dependence ◽  
Burning Velocity ◽  
Optimization Procedure ◽  
Optimal Parameters ◽  
Velocity Measurements ◽  
Equilibrium Calculations

The optimization procedure was developed to derive the global kinetic parameters using experimental dependence of burning velocity on the equivalence ratio. The simple model of laminar premixed flame propagation with assumed constant parameters was used to demonstrate the features of the suggested procedure. The suggested method allows finding optimal parameters for the defined functional dependence of the reaction rate on the temperature and reactant concentrations. The dependence of combustion adiabatic temperature on equivalence ratio is assumed to be known from the flame equilibrium calculations. The global kinetic parameters of combustion reaction were determined for methane, ethylene and propane mixtures with air on the basis of experimental data on burning velocity as function of the equivalence ratio. The calculated overall kinetic parameters are compared with parameters obtained by other methods within similar global model.

scholarly journals EXPERIMENTAL DETERMINATION OF LAMINAR BURNING VELOCITY OF BIOGAS AT PRESSURES UP TO 5 BAR

2018 ◽  
Vol 17 (2) ◽  
pp. 03
Author(s):  
L. Pizzuti ◽  
C. A. Martins ◽  
L. R. Santos
Keyword(s):  
Equivalence Ratio ◽  
Burning Velocity ◽  
Initial Pressure ◽  
Experimental Setup ◽  
Laminar Burning Velocity ◽  
Gaseous Mixtures ◽  
Experimental Procedure ◽  
Constant Volume Combustion Chamber ◽  
Percentage Standard Deviation

This paper presents a very detailed description of a new cylindrical constant volume combustion chamber designed for laminar burning velocity determination of gaseous mixtures at ambient temperature and initial pressure up to 6 bar. The experimental setup, the experimental procedure and the determination of the range of flame radius for laminar burning determination are all described in details. The laminar burning velocity of twelve synthetic biogas mixtures has been studied. Initial pressure varying between 1 and 5 bar, equivalence ratios, f, between 0.7 and 1.1 and percentage dilution, with a mixture of CO2 and N2, between 35 and 55% have been considered. Five experiments were run for each mixture providing a maximum percentage standard deviation of 8.11%. However, for two third of the mixtures this value is lower than 3.55%. A comparison with simulation using PREMIX for both GRI-Mech 3.0 and San Diego mechanisms has provided closer agreement for mixtures with equivalence ratio closer to stoichiometry whereas for f = 0.7 the deviation is larger than 15% for all pressures. Mixtures with lower equivalence ratio, higher dilution percentage and higher initial pressure presents the lower values of laminar burning velocity.

FLAME PROPAGATION AND BURNING RATES OF METHANE-AIR MIXTURES USING SCHLIEREN PHOTOGRAPHY

2016 ◽  
Vol 78 (10-2) ◽  
Author(s):  
Mohd Suardi Suhaimi ◽  
Aminuddin Saat ◽  
Mazlan A. Wahid ◽  
Mohsin Mohd Sies
Keyword(s):  
Combustion Chamber ◽  
Burning Rate ◽  
Equivalence Ratio ◽  
Burning Velocity ◽  
Initial Pressure ◽  
Markstein Length ◽  
Constant Volume Combustion Chamber ◽  
Burning Rates ◽  
Schlieren Photography

Different methodology have been shown to produce different results for Markstein length and laminar burning velocity of methane-air mixture.This study attempts to determine the aforesaid parameters using the newly developed closed vessel combustion chamber with Schlieren photography. Markstein length and burning rate of methane-air mixture was determined under the initial pressure of 1 atm, temperature range of 298-302K and equivalence ratio range of 0.7-1.3. Experiments were performed in a centrally ignited 29.16L cylindrical constant volume combustion chamber. Ignition energy was set at 25mJ for each experiment. The images of spherically expanding flame were recorded using Schlieren photography technique at a speed of 2000 frame per second. Analysis of the flame area yield flame radii from which the flame speed and stretch rate could be obtained. These parameters would allow the determination of Markstein length and burning rate of the flame. Results show that Markstein length magnitude increases proportionally with equivalence ratio with a magnitude ranging from 0.125cm to 0.245cm. Maximum burning rate occurs at equivalence ratio of 1.1 with a magnitude of 0.366 m/s. Flame of each equivalence ratio also exhibits fluctuation arising from acoustic disturbance. This disturbance becomes more apparent at higher equivalence ratio.

MEASUREMENT OF STEROID BINDING PROTEINS

1970 ◽  
Vol 65 (1_Suppl) ◽  
pp. S104-S121 ◽  
Author(s):  
E. E. Baulieu ◽  
J. P. Raynaud ◽  
E. Milgrom
Keyword(s):  
Kinetic Parameters ◽  
Binding Proteins ◽  
Binding Specificity ◽  
Binding Parameters ◽  
Target Organs ◽  
Biological Mixtures ◽  
Steroid Binding Proteins ◽  
Steroid Binding ◽  
Steroid Binding Protein

ABSTRACT A brief review of the characteristics of steroid binding proteins found in the plasma and in some target organs is presented, followed by some general remarks on binding »specificity« and binding parameters. Useful techniques for measuring binding parameters at equilibrium are reported, both those which keep the equilibrium intact and those which implicate its disruption. A concept is developed according to which the determination of a specific steroid binding protein is based on the »differential dissociation« of the several steroid binding complexes present in most biological mixtures. Methods which allow determination of the kinetic parameters of the binding systems are also presented. Various representations of the binding and therefore different modes of graphic representation and calculation are discussed, including the recent »proportion graph« method.

Alcohol Determination by HPLC with Postcolumn Derivatization Based on the Thiosulfate-catalyzed Reaction of Alcohols and Cerium(IV) and Fluorescence Detection of Cerium(III)

2020 ◽  
Vol 16 ◽  
Author(s):  
Ikko Mikami ◽  
Eri Shibayama ◽  
Kengo Takagi
Keyword(s):  
Detection Limit ◽  
Fluorescence Detection ◽  
Reaction Rate ◽  
Detection Method ◽  
Fluorescence Detector ◽  
Reaction Solution ◽  
Optimum Detection ◽  
Postcolumn Derivatization ◽  
Sensitive Method

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

Kinetics and mechanism of redox reactions of U(III) ions with monochloroacetic and dichloroacetic acids

1979 ◽  
Vol 44 (2) ◽  
pp. 401-405 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Ľudovít Treindl
Keyword(s):  
Redox Reactions ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Outer Sphere ◽  
Alcohol Concentration ◽  
Kinetics And Mechanism ◽  
Solvent Structure ◽  
Influence Of Ph ◽  
Sphere Mechanism

The kinetics and mechanism of the redox reactions of U3+ ions with mono- and dichloroacetic acids were studied. The influence of pH was observed mainly in the second case and led to the determination of the rate constants and activation parameters corresponding to two parallel steps, namely oxidation of U3+ with CHCl2COO- ions and oxidation of U3+ with CHCl2.COOH molecules. The influence of binary mixtures of water with methanol, ethanol, isopropanol, or tert-butenol on the reaction rate was followed. Increasing alcohol concentration influences the rate constant not only through changing dielectric constant and solvation of the reactants but also through a change of the solvent structure which plays a role in reactions with an outer sphere mechanism of the electron transfer.

Decomposition of peroxobenzoic acid in benzene catalyzed by transition metal 2,4-pentanedionates

1984 ◽  
Vol 49 (3) ◽  
pp. 673-679 ◽  
Author(s):  
Pavel Lederer ◽  
Eva Mácová ◽  
Josef Vepřek-Šiška
Keyword(s):  
Transition Metal ◽  
Reaction Rate ◽  
Reaction Products ◽  
Acid Decomposition ◽  
Analogous Experiment ◽  
Catalytic Effects

The decomposition of peroxobenzoic acid in benzene was studied, and catalytic effects of Fe(III), Mn(III), Co(II), Co(III), and Cr(III) on the reaction rate and the composition of the reaction mixture were investigated. An analogous experiment carried out in perdeuterobenzene and determination of the distribution of deuterium in the reaction products provided evidence for the participation of the solvent in peroxobenzoic acid decomposition.

Regeneration Mechanism Studied by Potential-Time Response to Sinusoidal Current-Time Function

1997 ◽  
Vol 62 (10) ◽  
pp. 1511-1526
Author(s):  
María-Luisa Alcaraz ◽  
Ángela Molina
Keyword(s):  
Kinetic Parameters ◽  
Rate Constant ◽  
Theoretical Study ◽  
Time Function ◽  
Time Response ◽  
Current Time ◽  
Regeneration Mechanism ◽  
Sinusoidal Current ◽  
Regeneration Processes

A theoretical study of the potential-time response to sinusoidal current applied to static and dynamic electrodes for regeneration processes is presented. Methods for determination of the regeneration fraction, rate constant of the chemical reaction and heterogeneous kinetic parameters are proposed.

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