scholarly journals Dehydrogenation of Methylcyclohexane: Parametric Sensitivity of the Power Law Kinetics

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Muhammad R. Usman ◽  
David L. Cresswell ◽  
Arthur A. Garforth
Keyword(s):  
Activation Energy ◽  
Kinetic Model ◽  
Power Law ◽  
Operating Conditions ◽  
Nonlinear Dependence ◽  
Power Law Model ◽  
Parametric Sensitivity ◽  
Heterogeneous Catalytic ◽  
Wide Range ◽  
Kinetics Of

For heterogeneous catalytic reactions, the empirical power law model is a valuable tool that explains variation in the kinetic behavior with changes in operating conditions, and therefore aids in the development of an appropriate and robust kinetic model. In the present work, experiments are performed on 1.0 wt% Pt/Al2O3 catalyst over a wide range of experimental conditions and parametric sensitivity of the power law model to the kinetics of the dehydrogenation of methylcyclohexane is studied. Power law parameters such as order of the reaction, activation energy, and kinetic rate constants are found dependent upon the operating conditions. With H2 in the feed, both apparent order of the reaction and apparent activation energy generally increase with an increase in pressure. The results suggest a kinetic model, which involves nonlinear dependence of rate on the partial pressure of hydrogen and adsorption kinetics of toluene or some intermediate.

Macro Kinetics of N-Phosphonomethyliminodiacetic Acid Catalytic Oxidation

2012 ◽  
Vol 455-456 ◽  
pp. 872-879 ◽  
Author(s):  
Yan Bao ◽  
Jia Wu ◽  
Xiao Ping Hu
Keyword(s):  
Activation Energy ◽  
Kinetic Model ◽  
Measured Data ◽  
Second Step ◽  
Oxidizing Agent ◽  
Dissolved Oxygen Concentration ◽  
Exponential Factor ◽  
In Series ◽  
Kinetics Of ◽  
Made In

The oxidation of N-phosphonomethyliminodiacetic acid (PMIDA) to prepare glyphosate (PMG) over active carbon was investigated. Experiments were carried out with O2 as the oxidizing agent in a 150-mL autoclave made in stainless steel, with reaction temperature ranging from 323.15 to 353.25K and the pressure from 0.12 to 0.40 MPa. The macro kinetic model of the reactions in series was developed, and the pre-exponential factor and activation energy were estimated from the measured data in experiments. The influence of dissolved oxygen concentration was also considered in this macro kinetic model. The results indicated that the two step reactions are all one-order to reactant (PMIDA or PMG) and 0.3 or 0.07 to O2 respectively. The active energy was 12.98kJ/mol for the first step reaction and 10.87kJ/mol for the second step reaction.

scholarly journals Kinetics of barite reduction from refractory barite-sulphide ore

10.30544/237 ◽  
2016 ◽  
Vol 22 (4) ◽  
pp. 261-268 ◽  
Author(s):  
Miroslav D Sokić ◽  
Vladislav Matković ◽  
Jovica Stojanović ◽  
Branislav Marković ◽  
Vaso Manojlović
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Kinetic Model ◽  
Copper Sulphide ◽  
Influence Of Temperature ◽  
Sulphide Ore ◽  
Lead Zinc ◽  
Complex Structural ◽  
Kinetics Of ◽  
Maximum Removal

Refractory sulphide–barite ore was reduced with carbon in order to release lead, zinc, and copper sulphide from barite-pyrite base. Mineralogical investigations showed that due to the complex structural-textural relationships of lead, copper and zinc minerals with gangue minerals, it is not possible to enrich the ore using the conventional methods of mineral processing. The influence of temperature and time was studied to optimize the conditions, and to determine the kinetics of the barite reduction. The maximum removal of barite from ore was 96.7% at 900oC after 180 min. Chemically controlled kinetic model showed the best compliance with the experimental data. An activation energy of 142 kJ/mol was found.

Kinetic Study of the Dehydrogenation of Isobutane over V-K-O /ZSM5 Catalyst

2013 ◽  
Vol 798-799 ◽  
pp. 174-177 ◽  
Author(s):  
Teng Teng Wu ◽  
Cheng Xue Wang
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Kinetic Model ◽  
Atmospheric Pressure ◽  
Contact Time ◽  
Model Parameters ◽  
Isobutane Dehydrogenation ◽  
Dehydrogenation Reaction ◽  
Reaction Pressure ◽  
Kinetics Of

The reaction kinetics of the dehydrogenation of isobutane over V-K-O /ZSM5 catalyst was investigated. The powerfunction model was established;The isobutane dehydrogenation reaction tests were carried out between 833-863K and reaction pressure to atmospheric pressure by changing the contact time(w/F=0.464-0.532gh/mol) ,through the experimental data the kinetics of model parameters were analyzed.The results show that the power-function kinetic model is reasonable,the apparent activation energy is 177.7492KJ/mol.

scholarly journals Kinetic Model for Lead(II) Sorption on to Peat

1998 ◽  
Vol 16 (4) ◽  
pp. 243-255 ◽  
Author(s):  
Y.S. Ho ◽  
G. McKay
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Kinetic Model ◽  
Second Order ◽  
Sorption Rate ◽  
Sorption Model ◽  
Order Rate ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Order Rate Equation

The kinetics of lead sorption on to peat have been investigated. The batch sorption model, based on the assumption of a pseudo-second order mechanism, has been developed to predict the rate constant of sorption, the equilibrium capacity and initial sorption rate with the effect of initial lead(II) concentration, peat particle size and temperature. An equilibrium capacity of sorption has been evaluated with the pseudo-second order rate equation. In addition, an activation energy of sorption has also been determined based on the pseudo-second order rate constants.

Mean-field study of the synergic effect of the CO–NO reaction on a heterogeneous substrate of interconnected sectors

2010 ◽  
Vol 88 (4) ◽  
pp. 383-392
Author(s):  
Joaquín Cortés ◽  
Eliana Valencia
Keyword(s):  
Field Theory ◽  
Activation Energy ◽  
Kinetic Model ◽  
Bimetallic Catalyst ◽  
Reaction Order ◽  
Mean Field Theory ◽  
Mean Field ◽  
Reduction Reaction ◽  
Synergic Effect ◽  
Heterogeneous Catalytic

A mean-field theory study is made of the behaviour of a kinetic model of the reduction reaction of NO by CO catalyzed by a surface with simple heterogeneity consisting of two interconnected sectors that differ in their NO dissociation activation energy. A synergistic effect is manifested in the activity, apparent activation energy, and reaction order of the system. This situation, analogous to that observed in the literature in the case of a heterogeneous catalytic particle, is used in the paper to analyze a real case of a bimetallic catalyst.

Modelling of catalytic hydrocracking and fractionation of refinery vacuum residue

2014 ◽  
Vol 68 (12) ◽  
Author(s):  
Eduard Manek ◽  
Juma Haydary
Keyword(s):  
Kinetic Model ◽  
Residence Time ◽  
Aspen Plus ◽  
Vacuum Distillate ◽  
Operating Conditions ◽  
Vacuum Residue ◽  
Yield Model ◽  
Conversion Model ◽  
The Impact ◽  
Kinetics Of

AbstractThe main objective of this work was to create a kinetic model of refinery vacuum residue hydrocracking and to monitor the impact of the operating conditions on the product yields. Data and yield measurements were gathered from a residual hydrocracking unit (RHC). Reaction temperature ranged from 401°C to 412°C at the pressure of 18–20 MPa. A simplified kinetic yield model was applied; where the feed and each product fraction are represented by one lump (reactant or product of cracking) represented by the number of pseudo-components. The product fractions were determined by fractional distillation of the output mixture from the reactor. The kinetic model includes eight reaction steps and the following six fractions: vacuum residue, vacuum distillate, gas oil, kerosene, naphtha, and gas. In addition, a model for hydrodesulphurisation has been proposed. The average relative deviation between model and experimental yields was 5.36 %, and that for the sulphur conversion model was 1.04 %. An Excel file with the kinetic model was implemented in the Aspen Plus program using a user-defined model of the reactor. This model allows to input/output data between the Aspen Plus and Excel programs. The Excel subroutine calculates the reaction kinetics of cracking from the set temperature and residence time, and distributes the products into 30 pseudo-components created in the Aspen Plus program. The remaining part of the RHC unit was simulated in the Aspen Plus environment. The effects of the reaction conditions such as temperature and residence time on the conversion of the feed and on the distillation curves of the output mixture from the reactor were investigated. The model was verified by comparison of the distillation curves of simulated and real products.

Microcalorimetry and Kinetics of Biodiesel

2014 ◽  
Vol 592-594 ◽  
pp. 1647-1651
Author(s):  
S.P. Sivapirakasham ◽  
A. Afsal Khan ◽  
Mane G. Yogesh ◽  
R. Anand
Keyword(s):  
Activation Energy ◽  
Kinetic Model ◽  
Heating Rate ◽  
Diesel Fuel ◽  
Fossil Fuel ◽  
Uniform Heating ◽  
Nitrogen Gas ◽  
Gas Atmosphere ◽  
Great Acceptance ◽  
Kinetics Of

Now a day biodiesel becomes best alternative for diesel fuel. Thermogravimetry technique has great acceptance in the field of fossil fuel. The thermal and kinetics properties of diesel and Jatropha biodiesel are analyzed by using popular technique of thermogravimetry. The aim is to study the behavior of diesel, biodiesel and their blends in Nitrogen gas atmosphere at the heating rate of 5K/min, 10K/min and 15K/min from 30°C to 600°C. From study it is found that as heating rate increases peak is shifting toward higher value which shows that there is less uniform heating. The study clearly shows biodiesel is more stable than diesel indicating that transesterification make sample less stable. The Arrehenius Kinetic model is applied to study the activation energy. As percentage of biodiesel increases, stability of sample increases and hence increases in activation energy

scholarly journals Isothermal kinetics of titanium-oxo-alkoxy clusters formation

2011 ◽  
Vol 43 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Z.Z. Baros ◽  
B.K. Adnadjevic ◽  
V.B. Pavlovic
Keyword(s):  
Activation Energy ◽  
Power Law ◽  
Isothermal Kinetics ◽  
Molar Ratio ◽  
Titanium Tetraisopropoxide ◽  
Formation Reaction ◽  
Formation Kinetics ◽  
Power Law Function ◽  
Absorbance Changes ◽  
Kinetics Of

In this article, the influences of titanium tetraisopropoxide Ti(OR)4 (R = Pri) concentration, molar ratio, h = [H2O]/[Ti(OR)4], and temperature, on the formation kinetics of the titanium-oxo-alkoxy clusters (TOAC), were studied. The TOAC formation isothermal kinetics was monitored by measuring absorbance changes versus time in the reaction mixture at predefined wavelength ? = 350 nm. It was determined that the isothermal rate of clusters formation is a power law function of titanium tetraisopropoxide concentration and the molar concentration of water (cw). The kinetic parameters ? and ? were calculated. The apparent activation energy Ea values in the clusters formation reaction has been calculated and correlated with the change of titanium tetraisopropoxide concentration and molar ratio. The model for mechanism of TOAC formation is proposed.

scholarly journals Methodology for calculating the pre-exponential factor using the isoconversional principle for the numerical simulation of the air injection process

2019 ◽  
Vol 9 (1) ◽  
pp. 37-46
Author(s):  
Jorge Mario Padilla- Reyes ◽  
Marta Liliana Trujillo -Portillo ◽  
Eider Niz- Vel´asquez
Keyword(s):  
Kinetic Model ◽  
Oxidation Process ◽  
Combustion Process ◽  
Operating Conditions ◽  
Air Injection ◽  
Oil Oxidation ◽  
Temperature Oxidation ◽  
Exponential Factor ◽  
Injection Process ◽  
Kinetics Of

The main challenge to predict at Field scale the performance of an air injection process is to understand the oil oxidation process and to have a kinetic model of reactions enabling the prediction of process behavior in a reservoir numerical simulator, under different operating conditions.   Recently, the Isoconversional Principle has been implemented for studying the kinetics of reactions associated with oil oxidation during air injection, based on Ramped Temperature Oxidation tests (RTO). In different published papers, the isoconversional analysis has been used to study the oxidation characteristics of different rock-fluid systems, identify groups of dominant reactions during the crude oil oxidation process, and estimate the effective activation energy for each of the identified reactions.   However, in none of them has a procedure been established for estimating the pre-exponential factor, as this is not a direct measure of isoconversional methods. In this article, a mathematical procedure is proposed for estimating the pre-exponential factor based on the application of Friedman's isoconversional method, inteded for characterizing the kinetics of the reactions associated with the In Situ Combustion process.  This procedure was validated with experimental information and a kinetic model proposed in the literature to model the oxidation behavior of heavy crude.

Modeling and Experimental Investigation of Bubble Formation in Shear-Thinning Liquids

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Mohamad Taghi Esfidani ◽  
Mohammad Reza Oshaghi ◽  
Hossein Afshin ◽  
Bahar Firoozabadi
Keyword(s):  
Power Law ◽  
High Speed ◽  
Gas Flow ◽  
Bubble Formation ◽  
Experimental Studies ◽  
Methyl Cellulose ◽  
Operating Conditions ◽  
Wide Range ◽  
Bubble Sizes ◽  
Newtonian Liquids

This investigation presents both theoretical and experimental studies on the size of a growing bubble in power-law non-Newtonian liquids. At first, some previous works on the prediction of bubble size in Newtonian liquids have been extended by considering the balance of forces acting on the bubble at the moment of separation. Predicted bubble sizes were validated against the experimental results for a wide range of operating conditions, including different gas flow rates and needle diameters as well as a wide range of physical properties of the Newtonian liquids. Furthermore, in order to determine the size of the bubbles formed in power-law non-Newtonian liquids with a similar analysis, the effective shear rate of bubble growth was calculated in which the rheological properties of fluid were taken into account and subsequently the viscosity of the fluid was modified. Theoretically obtained bubble sizes for non-Newtonian liquids are in a good agreement with our experimental high-speed video observations of three carboxyl methyl cellulose (CMC) solutions.

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