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

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.

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

Water Science & Technology ◽

10.2166/wst.2001.0655 ◽

2001 ◽

Vol 44 (10) ◽

pp. 333-339 ◽

Cited By ~ 23

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.

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Kajian Dehidroksilasi Termal Kaolin menjadi Metakaolin menggunakan Analisis Termogravimetri

ALCHEMY Jurnal Penelitian Kimia ◽

10.20961/alchemy.17.1.47337.105-112 ◽

2021 ◽

Vol 17 (1) ◽

pp. 105

Author(s):

Aprilina Purbasari ◽

Tjokorde Walmiki Samadhi

Keyword(s):

Fourier Transform ◽

Thermogravimetric Analysis ◽

Fourier Transform Infrared ◽

Reaction Model ◽

Order Reaction ◽

X Ray Diffraction ◽

Exponential Factor ◽

X Ray ◽

First Order ◽

Air Atmosphere

Kaolin merupakan mineral yang banyak dimanfaatkan di berbagai industri. Kaolin dapat diubah menjadi metakaolin yang lebih reaktif melalui proses dehidroksilasi termal. Pada penelitian ini, proses dehidroksilasi termal kaolin dari Bangka Belitung menjadi metakaolin dikaji menggunakan analisis termogravimetri pada rentang suhu 30 – 900 °C dengan laju pemanasan 10 °C/menit dalam lingkungan atmosfer udara. Kaolin mengalami empat tahap dekomposisi dan dehidroksilasi kaolin menjadi metakaolin terjadi pada suhu sekitar 450 – 600 °C. Berdasarkan metode Coats dan Redfern, dehidroksilasi kaolin mengikuti model reaksi order satu dengan energi aktivasi 271,66 kJ/mol dan faktor pre-eksponensial 6,13×1015 s-1. Hasil analisis menggunakan spektroskopi X-ray diffraction (XRD) dan Fourier Transform Infrared (FTIR) pada kaolin setelah dipanaskan pada suhu 550 °C selama 3 jam menunjukkan bahwa sebagian besar kaolin telah berubah menjadi metakaolin.Study of Thermal Dehydroxylation of Kaolin to Metakaolin using Thermogravimetric Analysis. Kaolin is a mineral that is widely used in various industries. Kaolin can be converted into metakaolin which is more reactive through thermal dehydroxylation processes. In this study, thermal dehydroxylation process of Bangka Belitung kaolin into metakaolin was studied using thermogravimetric analysis in a temperature range of 30 – 900 °C with a heating rate of 10 oC/min in an air atmosphere condition. Kaolin underwent four stages of decomposition and dehydroxylation of kaolin into metakaolin occured at temperatures around 450 – 600 °C. Based on the Coats and Redfern method, kaolin dehydroxylation followed first order reaction model with activation energy of 271.66 kJ/mol and pre-exponential factor of 6.13×1015 s-1. The analysis using X-ray diffraction (XRD) dan Fourier Transform Infrared (FTIR) spectroscopy on kaolin after heating at temperature of 550 °C for 3 hours showed that most of the kaolin had turned into metakaolin.

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

Applied Sciences ◽

10.3390/app112311300 ◽

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.

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STUDY OF THERMAL DECOMPOSITION AND IGNITION TEMPERATURE OF BAGASSE, COAL AND THEIR BLENDS

Revista de Engenharia Térmica ◽

10.5380/reterm.v9i1-2.61937 ◽

2010 ◽

Vol 9 (1-2) ◽

pp. 81 ◽

Cited By ~ 7

Author(s):

D. A. Mortari ◽

I. Avila ◽

A. M. Dos Santos ◽

P. M. Crnkovic

Keyword(s):

Thermal Decomposition ◽

Sugar Cane ◽

Ignition Temperature ◽

Synergistic Effects ◽

Combustion Process ◽

Nitrogen Atmosphere ◽

Sugar Cane Bagasse ◽

Model Free ◽

Air Atmosphere ◽

The Stability

In Brazil, due to its availability, sugar cane bagasse has a high potential for power generation. The knowledge of ignition behavior, as well as the knowledge of the chemical kinetics, in of fuels combustion process is important features in boilers projects and in the stability of the combustion process control. The aim of this study is to investigate the thermal behavior of sugar cane bagasse, coal and their blends. The methodology proposed by Tognotti et al. (1985) was applied to determine the ignition temperature for all samples. Ignition temperatures were 256oC for neat bagasse and 427oC for neat coal, and 275oC for both blends (50-50% and 25-75%). The Model-Free Kinetics was applied to determine the apparent activation energy (Eα) of the thermal decomposition of sugar cane bagasse. For the two major events of mass loss of bagasse which correspond to the thermal decomposition of organic matter (mainly hemicellulose, cellulose and lignin), average values of Eα were obtained for both combustion and pyrolysis processes. In synthetic air atmosphere, the Eα were 170.8±26.3 kJ⋅mol-1 and 277.8±58.6 kJ⋅mol-1, while in nitrogen atmosphere, the Eα were 185.0 ± 11.4 kJ⋅mol-1 and 82.1±44.4 kJ⋅mol-1. The results obtained can be explained by synergistic effects when both bagasse and coal were blended, changing the fuel reactivity.

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Non-Isothermal Kinetic Analysis of the Dehydroxylation of Kaolinite in Dynamic Air Atmosphere

Acta Technologica Agriculturae ◽

10.1515/ata-2017-0010 ◽

2017 ◽

Vol 20 (2) ◽

pp. 52-56 ◽

Cited By ~ 1

Author(s):

Tomáš Ondro ◽

Tomáš Húlan ◽

Ivan Vitázek

Keyword(s):

Activation Energy ◽

Kinetic Analysis ◽

Heating Rates ◽

Third Order ◽

Exponential Factor ◽

Mean Values ◽

Air Atmosphere ◽

Powder Samples ◽

Isothermal Kinetic Analysis ◽

Isothermal Kinetic

Abstract A non-isothermal kinetic analysis of kaolinite dehydroxylation was carried out using thermogravimetric analysis on powder samples with heating rates from 1 to 30 °C・min-1 in a dynamic air atmosphere. The mechanism of the reaction, values of overall activation energy and pre-exponential factor were determined from a series of thermogravimetric experiments by the Coats- Redfern method. The results show that the dehydroxylation of kaolinite is controlled by the rate of the third-order reaction (F3) with the mean values of overall activation energy (EA) 255 kJ・mol-1 and pre-exponential factor (A) 25.56 × 1014 s-1.

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Analysis of Most Probable Mechanism Functions and Thermal Degradation Kinetics of N-Phenylmaleimide-Styrene-Maleic Copolymers

Polymers and Polymer Composites ◽

10.1177/096739110701500509 ◽

2007 ◽

Vol 15 (5) ◽

pp. 409-414

Author(s):

Wang Zhai-min ◽

Pi Pi-hui ◽

Wen Xiu-fang ◽

Cheng Jiang ◽

Yang Zhuo-ru

Keyword(s):

Thermal Degradation ◽

Degradation Kinetics ◽

Kinetic Method ◽

Probable Mechanism ◽

Thermal Degradation Kinetics ◽

Exponential Factor ◽

Differential Methods ◽

First Order Chemical Reaction ◽

Isothermal Kinetic ◽

Kinetics Of

The thermal degradation kinetics of N-phenylmaleimide-styrene-maleic (NSMA) anhydride copolymers was analysed by a non-isothermal kinetic method. Kinetic parameters were obtained using integral and differential methods, and the most probable mechanism functions and kinetic compensation effects were discussed. The activation energy E for the thermal degradation of NSMA was 211.34kJ/mol according to the Flynn-Wall-Ozawa method and the thermal degradation was a first-order chemical reaction. A recommended rate expression for the thermal degradation reaction of NSMA was [Formula: see text] (where α is the conversion, t is time, R is the gas constant, T is the temperature and A is the pre-exponential factor), and the mathematical expressions of compensation effects for the integral and differential methods were lnA=-1.8037+0.1749E and lnA=-2.1974+0.1741E respectively.

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Non-isothermal kinetic analysis of the thermal decomposition of spruce wood in air atmosphere

Research in Agricultural Engineering ◽

10.17221/115/2016-rae ◽

2018 ◽

Vol 64 (No. 1) ◽

pp. 41-46 ◽

Cited By ~ 9

Author(s):

Ondro Tomáš ◽

Vitázek Ivan ◽

Húlan Tomáš ◽

Lawson Michael K

Keyword(s):

Activation Energy ◽

Thermal Decomposition ◽

Picea Abies ◽

Heating Rates ◽

Air Atmosphere ◽

Spruce Wood ◽

Lignin Decomposition ◽

Main Decomposition ◽

Isothermal Kinetic Analysis ◽

Isothermal Kinetic

Thermal decomposition of spruce wood (Picea abies) was studied using the thermogravimetric (TG) analysis in air atmosphere from 30°C to 600°C with the heating rates of 5, 10, 15, 20, 25 and 30°C.min–1. The TG results show that the main decomposition region is in the temperature range of 250–360°C, where a total disintegration of hemicellulose and cellulose with partial lignin decomposition can be observed. The values of apparent activation energy for this process are between 168.6–196.5 kJ·mol–1, 179.8–188.1 kJ·mol–1 and 170.1–178.7 kJ·mol–1 determined by the Friedman, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods, respectively.

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Global Reaction Model to Describe the Kinetics of Catalytic Pyrolysis of Coffee Grounds Waste

Materials Science Forum ◽

10.4028/www.scientific.net/msf.899.173 ◽

2017 ◽

Vol 899 ◽

pp. 173-178 ◽

Cited By ~ 1

Author(s):

Ronydes Batista Jr. ◽

Bruna Sene Alves Araújo ◽

Pedro Ivo Brandão e Melo Franco ◽

Beatriz Cristina Silvério ◽

Sandra Cristina Danta ◽

...

Keyword(s):

Thermal Decomposition ◽

Large Scale ◽

Catalytic Pyrolysis ◽

Petroleum Products ◽

Reaction Model ◽

Heating Rates ◽

Coffee Grounds ◽

One Step ◽

Global Reaction ◽

The One

In view of the constant search for new sources of renewable energy, the particulate agro-industrial waste reuse emerges as an advantageous alternative. However, despite the advantages of using the biomass as an energy source, there is still strong resistance as the large-scale replacement of petroleum products due to the lack of scientifically proven efficient conversion technologies. In this context, the pyrolysis is presented as one of the most widely used thermal decomposition processes. The knowledge of aspects of chemical kinetics, thermodynamics these will, heat and mass transfer, are so important, since influence the quality of the product. This paper presents a kinetic study of slow pyrolysis of coffee grounds waste from dynamic thermogravimetric experiments (TG), using different powder catalysts. The primary thermal decomposition was described by the one-step reaction model, which considers a single global reaction. The kinetic parameters were estimated using nonlinear regression and the differential evolution method. The coffee ground waste was dried at 105°C for 24 hours. The sample in nature was analyzed at different heating rates, being 10, 15, 20, 30 and 50 K/min. In the catalytic pyrolysis, about 5% (w/w) of catalyst were added to the sample, at a heating rate of 30 K/min. The results show that the one-step model does not accurately represent the data of weight loss (TG) and its derivative (DTG), but can do an estimative of the activation energy reaction, and can show the differences caused by the catalysts. Although no one can say anything about the products formed with the addition of the catalyst, it would be necessary to micro-pyrolysis analysis, we can say the influence of the catalyst in the samples, based on the data obtained in thermogravimetric tests.

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