scholarly journals A Simple Direct Method to Obtain Kinetic Parameters for Polymer Thermal Decomposition

2021 ◽  
Vol 11 (23) ◽  
pp. 11300
Author(s):  
David Lázaro ◽  
Alain Alonso ◽  
Mariano Lázaro ◽  
Daniel Alvear
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Direct Method ◽  
Reaction Model ◽  
Exponential Factor ◽  
Gaseous Fuels ◽  
High Level ◽  
A Direct Method ◽  
Polymer Combustion ◽  
Model Expression

In a fire, the polymer combustion occurs when gaseous fuels react with oxygen. The heating of a material could force the release of gaseous fuels during thermal decomposition and pyrolysis. The rate of pyrolysis to define the gaseous fuels is usually interpreted by means of the Arrhenius expression and a reaction model expression, which are characterized by an activation energy, a pre-exponential factor, and a reaction order value. Many methods are available for determining kinetic parameters from thermogravimetric experimental data. However, the most challenging issue is achieving an adequate balance between accuracy and simplicity. This work proposes a direct method for determining the kinetic parameters with only a thermogravimetric experiment at a single heating rate. The method was validated with six polymers, and the results were compared with those from similar procedures, such as the Lyon method and generalized direct method. The results achieved using the simpler approach of the proposed method show a high level of accuracy.

scholarly journals Isothermal Kinetic Analysis of the Thermal Decomposition of Wood Chips from an Apple Tree

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 195
Author(s):  
Ivan Vitázek ◽  
Martin Šotnar ◽  
Stella Hrehová ◽  
Kristína Darnadyová ◽  
Jan Mareček
Keyword(s):  
Thermal Decomposition ◽  
Apple Tree ◽  
Combustion Process ◽  
Reaction Model ◽  
Wood Chips ◽  
Small Scale ◽  
Exponential Factor ◽  
Air Atmosphere ◽  
First Order Chemical Reaction ◽  
Isothermal Kinetic

The thermal decomposition of wood chips from an apple tree is studied in a static air atmosphere under isothermal conditions. Based on the thermogravimetric analysis, the values of the apparent activation energy and pre-exponential factor are 34 ± 3 kJ mol−1 and 391 ± 2 min−1, respectively. These results have also shown that this process can be described by the rate of the first-order chemical reaction. This reaction model is valid only for a temperature range of 250–290 °C, mainly due to the lignin decomposition. The obtained results are used for kinetic prediction, which is compared with the measurement. The results show that the reaction is slower at higher values of degree of conversion, which is caused by the influence of the experimental condition. Nevertheless, the obtained kinetic parameters could be used for the optimization of the combustion process of wood chips in small-scale biomass boilers.

Thermal processing of sewage sludge by drying, pyrolysis, gasification and combustion

2001 ◽  
Vol 44 (10) ◽  
pp. 333-339 ◽  
Author(s):  
P. Stolarek ◽  
S. Ledakowicz
Keyword(s):  
Thermal Decomposition ◽  
Sewage Sludge ◽  
Kinetic Parameters ◽  
Thermal Processing ◽  
Combustion Process ◽  
Order Kinetic ◽  
Municipal Sludge ◽  
Pyrolysis Kinetics ◽  
Exponential Factor ◽  
First Order

Thermal processing of sewage sludge including drying, pyrolysis and gasification or combustion may be an alternative to other ways of utilising it. In this paper thermogravimetric analysis (TGA) was employed in the investigation of thermal decomposition of sewage sludge. The kinetic parameters of drying, pyrolysis and gasification or combustion of sewage sludge have been determined in an inert-gas (argon) and additionally some series of the sludge decomposition experiments have been carried out in air, in order to compare pyrolysis and combustion. The pyrolysis char has been gasified with carbon dioxide. A typical approach to the kinetics of thermal decomposition of a solid waste is to divide the volatile evolution into a few fractions (lumps), each of which is represented by a single first-order reaction. If these lumps are assumed to be non-interacting and evolved by independent parallel reactions the first-order kinetic parameters such as activation energy Ei and pre-exponential factor Ai can be determined from mathematical evaluation of TG or DTG curves. The object of our investigations was a municipal sludge from the two wastewater treatment plants (WTP) in Poland. The experiments have been carried out in the thermobalance Mettler-Toledo type TGA/SDTA851 LF, in the temperature range 30-1,000°C. Five different values of heating rate have been applied β = 2, 5, 10, 15 and 20 K/min. The values of Ei and Ai have been determined for all recognised lumps of gaseous products. The method employed has also revealed its usefulness for the determination of kinetic parameters for municipal sludge, that possess an undefined content. An alternative route to combustion of sewage sludge is its gasification, which significantly increases the gaseous product (pyrolytic gas + syngas). Besides pyrolysis kinetics, gasification or combustion process kinetics have also been determined.

scholarly journals Application of the pseudoinverse computation in reconstruction of blurred images

Filomat ◽  
2012 ◽  
Vol 26 (3) ◽  
pp. 453-465 ◽  
Author(s):  
Sladjana Miljkovic ◽  
Marko Miladinovic ◽  
Predrag Stanimirovic ◽  
Igor Stojanovic
Keyword(s):  
Mathematical Model ◽  
Direct Method ◽  
Motion Blur ◽  
Linear Motion ◽  
Numerical Examples ◽  
High Level ◽  
Blurred Images ◽  
Programming Package ◽  
A Direct Method ◽  
Very High

We present a direct method for removing uniform linear motion blur from images. The method is based on a straightforward construction of the Moore-Penrose inverse of the blurring matrix for a given mathematical model. The computational load of the method is decreased significantly with respect to other competitive methods, while the resolution of the restored images remains at a very high level. The method is implemented in the programming package MATLand respective numerical examples are presented.

scholarly journals Influence of Liming on Kinetics of Sewage Sludge Pyrolysis

2019 ◽  
Vol 26 (1) ◽  
pp. 175-188
Author(s):  
Paweł Stolarek ◽  
Stanisław Ledakowicz ◽  
Radosław Ślęzak
Keyword(s):  
Thermal Decomposition ◽  
Sewage Sludge ◽  
Mass Loss ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Visual Analysis ◽  
Pyrolysis Kinetics ◽  
Exponential Factor ◽  
The Impact ◽  
Kinetics Of

Abstract Thermogravimetry (TG) is the fast and reliable method for characterization of thermal decomposition of any material and in particular to determine the kinetics of pyrolytic decomposition of sewage sludge. Two types of sewage sludge with and without addition of lime were investigated from kinetic point of view. For TG analysis samples of selected sewage sludge were heated under the inert atmosphere of argon with constant heating rate from 303 to 1273 K; the three heating rate β = 5, 10 and 20 K/min were chosen. The iso-conversion methods of Friedman and Ozawa-Flynn-Wall were employed for analysis of TG results. As the sewage sludge decomposition is very complex process it cannot be described by a simple stoichiometric equation, therefore the so called lumping of reactions in the selected temperature ranges were used with detailed principles arising from visual analysis of DTG curve. The deconvolution of DTG curves performed according to Fraser-Suzuki asymmetric profile allowed the identification of number of lumps and their contribution to the overall mass loss. So the decomposition of sewage sludge with lime addition could be described with five groups of reactions while the one without lime by means of six lumps. The thermal decomposition of sewage sludge was assumed to proceed according to the scheme of parallel concurrent independent reactions of n-th order. The values of the apparent activation energies at different constant values of conversion degrees were determined by the iso-conversion analysis. To estimate the kinetic parameters the non-linear regression with Levenberg-Marquart optimization procedure was used. The kinetic parameters such as activation energy, pre-exponential factor, reaction order and fraction of total mass loss associated with a given reaction were determined. The impact of sewage sludge liming revealed in essential differences of pyrolysis products and pyrolysis kinetics of limed sludge and without lime one was highlighted.

scholarly journals Kinetics of the thermal decomposition of pine needles

2015 ◽  
Vol 7 (1) ◽  
pp. 5-22 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Jitendra Gangwar
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Pine Needles ◽  
Experimental Results ◽  
Pyrolysis Process ◽  
Order Model ◽  
Exponential Factor ◽  
First Order ◽  
Model Free ◽  
Good Agreement

Abstract A kinetic study of the pyrolysis process of pine needles was examined using a thermogravimetric analyser. The weight loss was measured in nitrogen atmosphere at a purge flow rate of 100 ml/min. The samples were heated over a range of temperature of 19°C–600°C with a heating rate of 10°C/min. The results obtained from the thermal decomposition process indicate that there are three main stages: dehydration, active and passive pyrolysis. The kinetic parameters for the different samples, such as activation energy and pre-exponential factor, are obtained by the shrinking core model (reaction-controlled regime), the model-free, and the first-order model. Experimental results showed that the shrinking model is in good agreement and can be successfully used to understand degradation mechanism of loose biomass. The result obtained from the reaction-controlled regime represented actual values of kinetic parameters which are the same for the whole pyrolysis process; whereas the model-free method presented apparent values of kinetic parameters, as they are dependent on the unknown function ϕ(C), on the sum of the parameters of the physical processes, and on the chemical reactions that happen simultaneously during pyrolysis. Experimental results showed that values of kinetic constant from the first-order model and the SCM are in good agreement and can be successfully used to understand the behaviour of loose biomass (pine needles) in the presence of inert atmosphere. Using TGA results, the simulating pyrolysis can be done, with the help of computer software, to achieve a comprehensive detail of the devolatilization process of different types of biomasses.

Kinetic Investigation of Thermal Decomposition Reactions of Podophyllic Acid and Picropodophyllic Acid

2011 ◽  
Vol 391-392 ◽  
pp. 1230-1234
Author(s):  
Pu Hong Wen
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Model ◽  
Kinetic Parameters ◽  
Decomposition Reaction ◽  
Exponential Factor ◽  
Decomposition Reactions ◽  
Integral Forms ◽  
Free Energy Of Activation ◽  
Entropy Of Activation ◽  
Temperature Programmed

The thermal behavior and thermal decomposition kinetic parameters of podophyllic acid and picropodophyllic acid in a temperature-programmed mode have been investigated by means of DSC and TG-DTG. The kinetic model functions in differential and integral forms of the thermal decomposition reactions mentioned above for leading stage were established. The kinetic parameters of the apparent activation energy Ea and per-exponential factor A were obtained from analysis of the TG-DTG curves by integral and differential methods. The most probable kinetic model function of the decomposition reaction in differential form was 2/3•α-1/2 for podophyllic acid and 1/2• (1-α)-1 for picropodophyllic acid. The values of Ea indicated that the reactivity of picropodophyllic acid was highter than that of podophyllic acid in the thermal decomposition reaction. The values of the entropy of activation ΔS≠, enthalpy of activation ΔH≠ and free energy of activation ΔG≠ of the reactions were estimated.

Kinetic Investigation of Thermal Decomposition Reactions of 4'-Demethypodophyllotoxin and Podophyllotoxin

2013 ◽  
Vol 800 ◽  
pp. 517-521
Author(s):  
Pu Hong Wen
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Model ◽  
Kinetic Parameters ◽  
Decomposition Reaction ◽  
Exponential Factor ◽  
Decomposition Reactions ◽  
Integral Forms ◽  
Free Energy Of Activation ◽  
Entropy Of Activation ◽  
Temperature Programmed

The thermal behavior and thermal decomposition kinetic parameters of podophyllotoxin (PPT) and 4-demethypodophyllotoxin (DMPPT) in a temperature-programmed mode have been investigated by means of DSC and TG-DTG. The kinetic model functions in differential and integral forms of the thermal decomposition reactions mentioned above for leading stage were established. The kinetic parameters of the apparent activation energy Ea and per-exponential factor A were obtained from analysis of the TG-DTG curves by integral and differential methods. The most probable kinetic model function of both decomposition reactions in differential form was (1-α) 2. The values of Ea indicated that the reactivity of PPT was higher than that of DMPPT in the thermal decomposition reaction. The values of the entropy of activation ΔS≠, enthalpy of activation ΔH≠ and free energy of activation ΔG≠ of the reactions were estimated.

scholarly journals Recovery of Aluminum from Aluminum Coated Plastic Waste using Pyrolysis Process

REAKTOR ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 38
Author(s):  
Chairul Irawan ◽  
Rinny Jelita ◽  
Iryanti Fatyasari Nata
Keyword(s):  
Kinetic Parameters ◽  
Room Temperature ◽  
Pyrolysis Temperature ◽  
Reaction Model ◽  
Plastic Waste ◽  
Pyrolysis Process ◽  
Exponential Factor ◽  
Aluminum Metal ◽  
Reactor Temperature ◽  
Effects Of Temperature

This study aims to separate aluminum metal in aluminum coated plastic waste so that it is known the obtained aluminum characteristics, to study the effects of temperature on the yield of solids and aluminum,  and to get the kinetic parameters that describe the effects of temperature on pyrolysis process rate. Plastic waste was cleaned, dried, cut, and weighed as much as 100 grams. Pyrolysis lasted in room temperature in 2 hours after the pyrolysis temperature was reached, i.e. 450oC. The formed smoke was condensed and weighed every 10 minutes from the first droplet until the pyrolysis time was completed. The remaining solids in the reactor were taken after the pyrolysis was completed and reactor temperature reached room temperature. The aluminum mixture was subsequently melted, molded and cooled. Experiments were repeated in various pyrolysis temperature variations (500°C, 550°C, 600°C and 650°C). The results show that the increase of pyrolysis temperature will decrease the yield of solids, while the aluminum yield remains. The obtained aluminum metal is 5.3% against the initial plastic mass in purity of 95.80%. The kinetic model representing plastic pyrolysis process is a single reaction model with the value of kinetic parameters of pre-exponential factor (A) 18.2689 min-1 and the activation energy value (E) 40.2310 kJ/mole.   Keywords: aluminum, pyrolysis, plastic wastes, temperature, kinetic parameter

Kinetic Investigation of Thermal Decomposition Reaction of Ethane-1,2-Diamine Copper(II) Chloride, C2H8N2CuCl2

2014 ◽  
Vol 665 ◽  
pp. 255-259
Author(s):  
Pu Hong Wen
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Decomposition Reaction ◽  
Kinetic Investigation ◽  
Thermal Decomposition Process ◽  
Exponential Factor ◽  
Free Energy Of Activation ◽  
Enthalpy Of Activation ◽  
Entropy Of Activation ◽  
Temperature Programmed

:The thermal behavior and thermal decomposition kinetic parameters of ethane-1,2-diamine copper (II) chloride (EDCC) in a temperature-programmed mode have been investigated by mean of TG-DTG. There are four stages in the thermal decomposition process. The kinetic parameters of the apparent activation energyEa(130.2, 143.6 and 158.9 KJ·mol–1) and per-exponential factorA(1011.80, 1012.18and 1011.83s–1) in II, III and IV stages were obtained from analysis of the TG-DTG curves by Kissinger method. The values ofEaindicated that the difficulty coefficient of pyrolysis in II, III and IV stages was increased in the order: II < III < IV. The values of the entropy of activation ΔS≠, enthalpy of activation ΔH≠and free energy of activation ΔG≠of the reaction were estimated.

scholarly journals Comparative Kinetic Analysis of CaCO3/CaO Reaction System for Energy Storage and Carbon Capture

2019 ◽  
Vol 9 (21) ◽  
pp. 4601 ◽  
Author(s):  
Fedunik-Hofman ◽  
Bayon ◽  
Donne
Keyword(s):  
Activation Energy ◽  
Energy Storage ◽  
Kinetic Analysis ◽  
Kinetic Parameters ◽  
Carbon Capture ◽  
Model Fitting ◽  
Reaction System ◽  
Reaction Model ◽  
Activation Energies ◽  
Exponential Factor

The calcium carbonate looping cycle is an important reaction system for processes such as thermochemical energy storage and carbon capture technologies, which can be used to lower greenhouse gas emissions associated with the energy industry. Kinetic analysis of the reactions involved (calcination and carbonation) can be used to determine kinetic parameters (activation energy, pre-exponential factor, and the reaction model), which is useful to translate laboratory-scale studies to large-scale reactor conditions. A variety of methods are available and there is a lack of consensus on the kinetic parameters in published literature. In this paper, the calcination of synthesized CaCO3 is modeled using model-fitting methods under two different experimental atmospheres, including 100% CO2, which realistically reflects reactor conditions and is relatively unstudied kinetically. Results are compared with similar studies and model-free methods using a detailed, comparative methodology that has not been carried out previously. Under N2, an activation energy of 204 kJ mol-1 is obtained with the R2 (contracting area) geometric model, which is consistent with various model-fitting and isoconversional analyses. For experiments under CO2, much higher activation energies (up to 1220 kJ mol-1 with a first-order reaction model) are obtained, which has also been observed previously. The carbonation of synthesized CaO is modeled using an intrinsic chemical reaction rate model and an apparent model. Activation energies of 17.45 kJ mol-1 and 59.95 kJ mol-1 are obtained for the kinetic and diffusion control regions, respectively, which are on the lower bounds of literature results. The experimental conditions, material properties, and the kinetic method are found to strongly influence the kinetic parameters, and recommendations are provided for the analysis of both reactions.

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