scholarly journals Stochastic Analysis of Multi-Reaction Model for Non-Linear Thermal History

2019 ◽  
Vol 22 (3) ◽  
pp. 92-98
Author(s):  
Alok Dhaundiyal ◽  
Suraj Bhan Singh
Keyword(s):  
Activation Energy ◽  
Thermal History ◽  
Reaction Order ◽  
Frequency Factor ◽  
Reaction Model ◽  
Thermal Profile ◽  
Location Parameters ◽  
Stochastic Function ◽  
Non Linear ◽  
The Ideal

Abstract This paper investigates the effect of non-linear thermal profile on the numerical solution of the multi-reaction model. According to the practical perspective, the temperature distribution at a different section of pyrolysis reactor is not necessarily following the ideal thermal history; therefore, it is necessary to predict the behaviour of the system for the higher degree of freedom. TG thermogram is obtained by the thermal degradation of pine needles sample in the thermogravimetric analyser (TGA). The activation energy, frequency factor, reaction order and the scale, shape and location parameters of a stochastic function are estimated for the non-linear parabolic thermal profile. The conventional Laplace integral is used to approximate the multi-reaction model. Activation energy obtained for the non-thermal profile lies in the range of 57.5–60 kJ·mol−1, whereas the frequency factor varies from 103–105 min-1. The obtained value of reaction order (n) lies in the domain of (0.9, 1.6).

Study on the Kinetics of Wet Flue Gas Desulfurization by Carbide Slag

2011 ◽  
Vol 322 ◽  
pp. 252-255
Author(s):  
Sheng Yu Liu ◽  
Li Chao Nengzi ◽  
Cheng Wei Lu ◽  
Wei Qiu ◽  
Yun Ming Hu
Keyword(s):  
Activation Energy ◽  
Chemical Reaction ◽  
Flue Gas ◽  
Reaction Order ◽  
Frequency Factor ◽  
Reaction Model ◽  
Flue Gas Desulfurization ◽  
Economic Costs ◽  
Carbide Slag ◽  
Kinetics Of

Current industrial desulfurization processes involve in economic costs, if carbide slag can be used in those processes, the costs will be reduced and the goal treating waste with waste can be achieved. A mathematic reaction model was built based on the chemical reaction of desulfurization by carbide slag, the overall reaction order n=α+β=1.74, the activation energy Ea=21749.56173J/mol and the frequency factor k0=0.349533643 .

scholarly journals Asymptotic Approximations to the Isothermal Pyrolysis of Deodara Leaves using Gamma Distribution

2017 ◽  
Vol 22 (3) ◽  
pp. 263 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Suraj Singh
Keyword(s):  
Activation Energy ◽  
Mathematical Model ◽  
Gamma Distribution ◽  
Numerical Solutions ◽  
Reaction Order ◽  
Frequency Factor ◽  
Asymptotic Approximations ◽  
Distributed Activation Energy Model ◽  
Upper Limit ◽  
The Mathematical Model

The main aim of th is paper pivote d ar ound th e influence of some parameters relev ant to biomass pyrolys is on the numerical solutions of the nth order distributed activation energy model (DAEM) using the Gamma distribution. The upper limit of ‘dE’ integral, frequency factor, reaction order, and the shape and rate parameters of the Gamma distribution are investigated. Analys is of the mathematical model is done with the help of asymptotic expansion.

The Kinetics of Oxygen Delignification of Reed Kraft Pulp (I)-Kinetics of Delignification

2011 ◽  
Vol 236-238 ◽  
pp. 1420-1424
Author(s):  
Xiao Feng Pan ◽  
Le Fan Ma ◽  
Qin Qin Qu ◽  
Jia Liang Lan ◽  
Li Hong Tan
Keyword(s):  
Activation Energy ◽  
Reaction Time ◽  
Oxygen Pressure ◽  
Kraft Pulp ◽  
Reaction Order ◽  
Frequency Factor ◽  
Kappa Number ◽  
Alkali Concentration ◽  
Oxygen Delignification ◽  
Kinetics Of

The kinetics of reed kraft pulp oxygen delignification process is studied, suitable kinetics model determined is -dk/dt=Aexp(-E/RT) [OH-]b[PO2]cKa, and the parameters in the model is calculated. The function for estimation of the kappa number at different reaction time is established for the reed kraft pulp oxygen delignification process. The reaction order fitted is 6.72 for delignification (a), 0.87 for alkali concentration (b), and 0.62 for oxygen pressure(c), respectively. The activation energy E is 80.96KJ/mol and frequency factor A 1.5×104.

Combustion Kinetics Characteristics of Dry Distillation Coal Tar

2013 ◽  
Vol 652-654 ◽  
pp. 831-835 ◽  
Author(s):  
Bo Liu ◽  
Zhang Ming Shi ◽  
Jin Qiao He ◽  
Hui Fang Xu
Keyword(s):  
Activation Energy ◽  
Reaction Order ◽  
Coal Tar ◽  
Frequency Factor ◽  
Combustion Kinetics ◽  
Thermo Gravimetric ◽  
Thermo Gravimetric Analyzer ◽  
Dry Distillation ◽  
Burn Out ◽  
Dynamic Combustion

In order to improve burning-out characteristic of dry distillation coal tar, the sample of dry coal tar was investigated by thermo-gravimetric analyzer(TGA), and the sample’ properties of kinetics and burning-out were studied. The results show that the dry distillated tar combustion is mainly dynamic combustion with diffusive combustion as a supplement. The combustion activation energy was 30 kJ/mol above, but the activation energy, frequency factor and reaction order appeared change on the subsequent combustion. The dry distillated coal tar is easy to be ignited, but difficult to burn out, so its maximum burn out temperature is higher.

scholarly journals Thermal Decomposition Mechanism and Kinetics Study of Plastic Waste Chlorinated Polyvinyl Chloride

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2080 ◽  
Author(s):  
Ru Zhou ◽  
Biqing Huang ◽  
Yanming Ding ◽  
Wenjuan Li ◽  
Jingjing Mu
Keyword(s):  
Activation Energy ◽  
Polyvinyl Chloride ◽  
Reaction Order ◽  
Model Fitting ◽  
Reaction Model ◽  
Order Reaction ◽  
Order Model ◽  
Model Free ◽  
Fitting Method ◽  
Two Stages

Chlorinated polyvinyl chloride (CPVC), as a new type of engineering plastic waste, has been used widely due to its good heat resistance, mechanical properties and corrosion resistance, while it has become an important part of solid waste. The pyrolysis behaviors of CPVC waste were analyzed based on thermogravimetric experiments to explore its reaction mechanism. Compared with polyvinyl chloride (PVC) pyrolysis, CPVC pyrolysis mechanism was divided into two stages and speculated to be dominated by the dehydrochlorination and cyclization/aromatization processes. A common model-free method, Flynn-Wall-Ozawa method, was applied to estimate the activation energy values at different conversion rates. Meanwhile, a typical model-fitting method, Coats-Redfern method, was used to predict the possible reaction model by the comparison of activation energy obtained from model-free method, thereby the first order reaction-order model and fourth order reaction-order model were established corresponding to these two stages. Eventually, based on the initial kinetic parameter values computed by model-free method and reaction model established by model-fitting method, kinetic parameters were optimized by Shuffled Complex Evolution algorithm and further applied to predict the CPVC pyrolysis behaviors during the whole temperature range.

Study of Errors on Larch Wood Pyrolysis Kinetic Analysis

2015 ◽  
Vol 1096 ◽  
pp. 243-247
Author(s):  
Lan Shu Xu ◽  
Yi Cheng ◽  
Yu Yu Li ◽  
Rui Li
Keyword(s):  
Activation Energy ◽  
Kinetic Analysis ◽  
Reaction Order ◽  
Frequency Factor ◽  
Larch Wood ◽  
Wood Pyrolysis ◽  
Integral Methods ◽  
True Value ◽  
Reaction Orders ◽  
Pyrolysis Kinetic

Errors was generate when use integral methods to calculate pyrolysis kinetic. It was analyzed by considered the effects of methods and reaction orders. A α-T curve was established for the error discussion depending on basic kenotic theory. For analysis methods, both single curve and multiple curve methods can obtain reliable activation energy values (≤3%), but the error of frequency factor was significant (up to 40%). Frequency factor is sensitive to intercept changing and is also to reaction order. Magnitude error could show if reaction order deviates to true value.

Study of the Degradation of a Polyesther-Polyurethane by TGA and the Logistic Mixture Model

2008 ◽  
Vol 587-588 ◽  
pp. 525-528 ◽  
Author(s):  
Fernando Barbadillo ◽  
A. Fuentes ◽  
Salvador Naya ◽  
Ricardo Cao ◽  
José Luís Mier ◽  
...  
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Mixture Model ◽  
Reaction Order ◽  
Frequency Factor ◽  
Order Model ◽  
Polymeric Systems ◽  
Polyurethane Degradation ◽  
Logistic Mixture

The logistic mixture model was successfully studied previously in the separation of overlapping steps in some polymeric systems by the authors. In the present work, this method is applied to a polyesther-polyurethane degradation under air and inert atmospheres at several heat rates (5, 10, 15, 20 and 25 °C/min) in dynamic TGA. Every logistic component is fitted by reaction order, Johnson-Mehl-Avrami and Sestak-Berggren kinetics equations in order to calculate its kinetic parameters (activation energy, frequency factor and exponents). The reaction order model gives a good fitting and reproduces accurtelly the experimental curves. Johnson-Mehl-Avrami and Sestak- Berggren equations resulted to be not suitables because of the activation energy values obtained.

Electroreduction of Cr(VI) from solutions of bifunctional alcohols

1989 ◽  
Vol 54 (10) ◽  
pp. 2638-2643
Author(s):  
David I. Balanchivadze ◽  
Tamara R. Chelidze ◽  
Jondo J. Japaridze
Keyword(s):  
Activation Energy ◽  
Ethylene Glycol ◽  
Electrode Surface ◽  
Frequency Factor ◽  
Limiting Current ◽  
Factor Log ◽  
Standard Rate ◽  
Standard Rate Constant ◽  
Chromate Ion ◽  
Activation Energy Of Diffusion

The effect of bifunctional alcohols ethylene glycol (EG) and 1,2-propylene glycol (1,2 PG) on the kinetic parameters for the irreversible chromate ion reduction were investigated by polarographic and coulometric methods of analysis. The electroreduction of chromate ion in neutral bifunctional alcohol solutions proceeds according to the scheme: Cr(VI)–Cr(III)–Cr(II) and the values of the standard rate constant k*0 decrease in the order H2O > EG > 1,2 PG. The values of real activation energy, Q, activation energy of diffusion, QD, and frequency factor log A° have been calculated. The obtained values of QD as well as Q proved the diffusion nature of limiting current. The values of the frequency factor log A° decrease in the order H2O > EG > 1,2 PG, which points to a less favourable orientation of the electroactive ions at the electrode surface in glycols.

Catalyst Selection for Hydrogenation of 1,2-Dihydroacenaphthylene

1998 ◽  
Vol 63 (11) ◽  
pp. 1945-1953 ◽  
Author(s):  
Jiří Hanika ◽  
Karel Sporka ◽  
Petr Macoun ◽  
Vladimír Kysilka
Keyword(s):  
Activation Energy ◽  
Nickel Catalyst ◽  
Palladium Catalyst ◽  
Active Component ◽  
Reaction Order ◽  
Nickel Catalysts ◽  
Practical Application ◽  
Repeated Use ◽  
Selection For ◽  
Catalyst Selection

The activity of ruthenium, palladium, and nickel catalysts for the hydrogenation of 1,2-dihydroacenaphthylene in cyclohexane solution was studied at temperatures up to 180 °C and pressures up to 8 MPa. The GC-MS technique was used to identify most of the perhydroacenaphthylene stereoisomers, whose fractions in the product were found dependent on the nature of the active component of the catalyst. The hydrogenation was fastest on the palladium catalyst (3% Pd/C). The nickel catalyst Ni-NiO/Al2O3, which is sufficiently active also after repeated use, can be recommended for practical application. The activation energy of 1,2-dihydroacenaphthylene hydrogenation using this catalyst is 17 kJ/mol, the reaction order with respect to hydrogen is unity.

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