scholarly journals Calcination thermokinetics of three Brazilian limestones

Cerâmica ◽  
2020 ◽  
Vol 66 (379) ◽  
pp. 297-306
Author(s):  
M. A. C. W. da Silveira ◽  
J. A. M. da Luz ◽  
G. L. de Faria ◽  
F. M. P. Coutinho
Keyword(s):  
Activation Energy ◽  
Energy Saving ◽  
Kinetic Parameters ◽  
Frequency Factor ◽  
Industrial Applications ◽  
Arrhenius Law ◽  
Calcination Process ◽  
Isothermal Method ◽  
Limestone Fines ◽  
Experimental Survey

Abstract Limestone and lime producers inadvertently generate a considerable amount of fine material during their processing, consequently becoming a great environmental liability. As far as the industrial calcination process is concerned, there is still a need for an experimental survey on Arrhenius law parameters, as apparent frequency factor and activation energy, referring to Brazilian limestones. The knowledge of these thermokinetic parameters may contribute to energy saving during the industrial calcination process, as well as for allowing the use of limestone fines in other industrial applications. This study aimed to characterize three Brazilian limestones by focusing on their laboratory-scale calcination using both quasi-isothermal and non-isothermal methods to estimate their kinetic parameters. The non-isothermal method (by thermogravimetric analyses) allowed estimating the activation energy for each limestone through the high calcination rate ranges. However, the kinetic parameters estimated by the quasi-isothermal method turned out in lower values, indicating the need to control the reactor atmosphere.

scholarly journals Pyrolysis Kinetic Parameters of Omari Oil Shale Using Thermogravimetric Analysis

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4060
Author(s):  
Ziad Abu El-Rub ◽  
Joanna Kujawa ◽  
Samer Al-Gharabli
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Kinetic Parameters ◽  
Oil Shale ◽  
Arrhenius Plot ◽  
Frequency Factor ◽  
Coefficient Of Determination ◽  
Assay Method ◽  
Temperature Integral ◽  
Integral Approximation

Oil shale is one of the alternative energies and fuel solutions in Jordan because of the scarcity of conventional sources, such as petroleum, coal, and gas. Oil from oil shale reservoirs can be produced commercially by pyrolysis technology. To optimize the process, mechanisms and rates of reactions need to be investigated. Omari oil shale formation in Jordan was selected as a case study, for which no kinetic models are available in the literature. Oil shale was analyzed using the Fischer assay method, proximate analysis (moisture, volatile, and ash), gross calorific value, elemental analysis (CHNS), and X-ray fluorescence (XRF) measurements. Non-isothermal thermogravimetric analysis was applied to study the kinetic parameters (activation energy and frequency factor) at four selected heating rates (5, 10, 15, and 20 °C/min). When oil shale was heated from room temperature to 1100 °C, the weight loss profile exhibited three different zones: drying (devolatilization), pyrolysis, and mineral decomposition. For each zone, the kinetic parameters were calculated using three selected methods: integral, temperature integral approximation, and direct Arrhenius plot. Furthermore, the activation energy in the pyrolysis zone was 112–116 kJ/mol, while the frequency factor was 2.0 × 107 − 1.5 × 109 min−1. Moreover, the heating rate has a directly proportional relationship with the rate constant at each zone. The three different methods gave comparable results for the kinetic parameters with a higher coefficient of determination (R2) for the integral and temperature integral approximation compared with the direct Arrhenius plot. The determined kinetic parameters for Omari formation can be employed in developing pyrolysis reactor models.

scholarly journals О термической устойчивости некоторых квазифуллеренов

2019 ◽  
Vol 61 (3) ◽  
pp. 604
Author(s):  
А.И. Подливаев ◽  
Л.А. Опенов
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Thermal Stability ◽  
Frequency Factor ◽  
Arrhenius Law ◽  
Method Of Molecular Dynamics ◽  
Temperature Dependences ◽  
Thermal Stability Of

AbstractThe thermal stability of recently predicted quasi-fullerenes С_20, С_42, С_48, and С_60 is studied by the method of molecular dynamics. The routes of their decomposition and the temperature dependences of their lifetimes are determined. The activation energy and frequency factor values that appear in the Arrhenius law are found. New isomers are detected.

scholarly journals Calculation of Kinetic Parameters of the Thermal Decomposition of Residual Waste of Coniferous Species: Cedrus Deodara

2018 ◽  
Vol 21 (2) ◽  
pp. 75-80 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Muammel M. Hanon
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Frequency Factor ◽  
Inert Atmosphere ◽  
Kissinger Method ◽  
Heating Rates ◽  
Cedrus Deodara ◽  
Coniferous Species ◽  
Competitive Reactions

Abstract This paper deals with pyrolysis decomposition of Cedrus deodara leaves with the help of thermogravimetric analysis (TGA). Experiments are performed in the presence of inert atmosphere of nitrogen. Experiments are conducted at three different heating rates of 5 °C∙min-1, 10 °C∙min-1 and 15 °C∙min-1 within temperature range of 35 °C to 700 °C. Arrhenius parameters such as activation energy and frequency factor are estimated by Flynn Wall and Ozawa (FWO), Kissinger-Akahira-Sonuse (KAS) and Kissinger. The activation energy and frequency factor calculated by using Kissinger method are 67.63 kJ∙mol-1 and 15.06 . 104 min-1 respectively; whereas the averaged values of the same parameters through FWO and KAS methods are 89.59 kJ∙mol-1 and 84.748 kJ∙mol-1, 17.27 . 108 min-1 and 62.13 . 107 min-1 respectively. Results obtained through Kissinger method represent the actual values of kinetic parameters. Conversely, FWO and KAS methods reflect the apparent values of kinetic parameters, as they are highly influenced by the overlapping of competitive reactions occur during pyrolysis.

scholarly journals Calculation of parameters for the model of an ideal phosphor

2016 ◽  
Vol 31 (2) ◽  
pp. 111-120 ◽  
Author(s):  
Zdravko Vejnovic ◽  
Milos Pavlovic ◽  
Pavle Hadzic ◽  
Milorad Davidovic
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Glow Curve ◽  
Filling Factor ◽  
Frequency Factor ◽  
Physical Parameters ◽  
Calculation Of Parameters ◽  
Kinetics Order

Equations for the calculation of kinetic parameters of thermoluminescent processes are theoretically derived for a model of an ideal phosphor. The values used in the calculation are obtained from glow curves and the function that describes the normalized glow curve generated. On the basis of this function, the equations for activation energy, frequency factor, and retrapping factor, were derived. All expressions are valid for a general case, when the filling factor of traps is f0?1. The concept of kinetics order was used for the calculation of parameters and the parameter of kinetics order was defined by means of real physical parameters. Results obtained by the analysis of synthetic curves and experimental glow curves of phosphor materials provide a deeper understanding of thermoluminescent kinetics.

scholarly journals The Kinetic Parameters of Carbonaceous Materials Activated with Potassium Hydroxide

2000 ◽  
Vol 18 (6) ◽  
pp. 573-580 ◽  
Author(s):  
Zou Yong ◽  
Han Bu-Xing
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Kinetic Parameters ◽  
Petroleum Coke ◽  
Potassium Hydroxide ◽  
Formation Energy ◽  
Frequency Factor ◽  
Carbonaceous Materials ◽  
Activation Temperature

On the basis of micropore formation in carbonaceous materials, the activation energy for the potassium hydroxide activation of Chinese petroleum coke and coal has been deduced theoretically as dB0/dt = A exp(–Ea∈/RT), where ∈ is the formation energy for the metastable solid formed at the activation temperature. The kinetic parameters (frequency factor, A, and apparent activation energy, Ea) were calculated from this equation as being 5.319 mg/(g min), 36.51 kJ/mol and 6.64 mg/(g min), 49.46 kJ/mol, respectively, for the two carbonaceous materials studied.

scholarly journals Distributed activation energy modelling for pyrolysis of forest waste using Gaussian distribution

2016 ◽  
Vol 70 (2) ◽  
pp. 64-70 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Suraj B. Singh
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Asymptotic Solution ◽  
Kinetic Parameters ◽  
Gaussian Distribution ◽  
Frequency Factor ◽  
Upper Limit ◽  
Forest Waste ◽  
Energy Modelling ◽  
Distribution Energy

Abstract The paper focuses on the influences of some factors significant to pyrolysis of forestry biomass on the asymptotic solution of the non-isothermal nth-order distribution energy model (DAEM) using Gaussian distribution. Investigated parameters are the integral upper limit, the frequency factor, and the heating rate parameters of the Gaussian distribution. The influence of these factors has been used for evaluating the kinetic parameters of the non-isothermal nth-order Gaussian distribution from thermogravimetric analysis of forest waste.

Can Biomarker Ratio Data Be Used Quantitatively to Constrain Thermal Histories? A Case Study from East Kalimantan, Indonesia

1996 ◽  
Vol 14 (6) ◽  
pp. 607-625
Author(s):  
Brett Mudford
Keyword(s):  
Activation Energy ◽  
Heat Flow ◽  
Kinetic Parameters ◽  
Frequency Factor ◽  
East Kalimantan ◽  
First Case ◽  
Ratio Data ◽  
Wide Range ◽  
Single Well ◽  
Thermal Histories

The determination of an appropriate thermal history in an exploration area is of fundamental importance when attempting to understand the evolution of the petroleum system. In this paper results are presented from a single-well modelling study in which bottom hole temperature data and three different biomarker ratio datasets were available to constrain the modelling. Previous quantitative investigations using biomarker ratios have been hampered by the wide variety of published kinetic parameters for biomarker evolution. Generally, these parameters have been determined either from measurements in the laboratory and extrapolation to the geological setting, or from downhole measurements where the heat flow history is assumed to be known. In the first case serious errors can arise because the heating rate is being extrapolated over many orders of magnitude, while in the second case errors can arise if the assumed heat flow history is incorrect. The utility of biomarker ratio data for constraining the heat flow has been assessed for a well in offshore East Kalimantan. In this case published kinetic parameters do a poor job of constraining the heat flow. In addition, compensation effects enable a wide range of activation energy and frequency factor pairs to produce equally good fits to the downhole data. This makes it difficult to invert downhole data to determine the heat flow history and the biomarker reaction parameters simultaneously. If independent estimates of the activation energy can be made, it is possible to use this information with an inversion procedure to constrain both the heat flow history and the frequency factors for the biomarker reactions. However, the compensation effect outlined in this paper may severely limit the practical, quantitative use of biomarker ratio data to constrain thermal histories.

scholarly journals Investigation on the Thermoluminescence Properties of KGdF4:Sm3+ Polycrystalline

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Phan Van Do
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Impurity Concentration ◽  
Frequency Factor ◽  
Neutron Dose ◽  
Rate Variation ◽  
Hydrothermal Technique ◽  
X Ray

KGdF4 polycrystalline doped with the different concentration of Sm3+ ions were synthesized by hydrothermal technique. Thermoluminescence (TL) glow curves of samples were measured in the range from 50 oC to 400 oC after irradiating beta, neutron and X-ray radiations. The response of TL intensity to impurity concentration and neutron dose were studied in detail. The TL kinetic parameters such as activation energy (E) and frequency factor (s) were estimated by using the method of heating rate variation.

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.

scholarly journals Asymptotic Approximations to the Non-Isothermal Distributed Activation Energy Model for Bio-Mass Pyrolysis

2017 ◽  
Vol 11 (4) ◽  
pp. 293-301 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Suraj B. Singh
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Gamma Distribution ◽  
Numerical Solutions ◽  
Frequency Factor ◽  
Energy Model ◽  
Erlang Distribution ◽  
Biomass Pyrolysis ◽  
Distributed Activation Energy Model ◽  
Thermoanalytical Data

AbstractThis paper describes the influence of some parameters significant to biomass pyrolysis on the numerical solutions of the non-isothermal nth order distributed activation energy model (DAEM) using the Gamma distribution and discusses the special case for the positive integer value of the scale parameter (λ), i.e. the Erlang distribution. Investigated parameters are the integral upper limit, the frequency factor, the heating rate, the reaction order, and the shape and rate parameters of the Gamma distribution. Influence of these parameters has been considered for the determination of the kinetic parameters of the non-isothermal nth order Gamma distribution from the experimentally derived thermoanalytical data of biomass pyrolysis. Mathematically, the effect of parameters on numerical solution is also used for predicting the behaviour of the unpyrolysized fraction of biomass with respect to temperature. Analysis of the mathematical model is based upon asymptotic expansions, which leads to the systematic methods for efficient way to determine the accurate approximations. The proposed method, therefore, provides a rapid and highly effective way for estimating the kinetic parameters and the distribution of activation energies.

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