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

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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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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Crystallization Kinetics of Seeded SBT ( Sr0.7Bi2.4Ta2O9 ) Powders from Sol-Gel Derived Precursors

MRS Proceedings ◽

10.1557/proc-688-c4.8.1 ◽

2001 ◽

Vol 688 ◽

Author(s):

Gopinathan M. A. Kumar ◽

Woo-Chul Kwak ◽

Se-Yon Jung ◽

Seung-Joon Hwang ◽

Yun-Mo Sung

Keyword(s):

Activation Energy ◽

Kinetic Analysis ◽

Crystallization Kinetics ◽

Sol Gel ◽

Metal Alkoxides ◽

Aurivillius Phase ◽

Strontium Bismuth Tantalate ◽

Isothermal Kinetic Analysis ◽

Isothermal Kinetic ◽

Kinetics Of

AbstractStrontium bismuth tantalate (SBT) having composition of Sr0.7Bi2.4Ta2O9 has been prepared through sol-gel method using their corresponding metal alkoxides as precursors. Seeded SBT powder was prepared by the addition of 5 wt.% of nanometer sized SBT particles to the sol followed by pyrolysis. By applying non-isothermal kinetic analysis to the DTA results, activation energy values for the unseeded and seeded samples were determined. Enhanced crystallization kinetics was observed for the seeded one and the activation energy for the aurivillius phase formation was found to be 318 kJ/mol, while 375 kJ/mol for the unseeded. The Avrami exponent values for the seeded and unseeded were found to be 2.80 and 0.96 respectively.

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Kinetics of Thermal Degradation of Viscose Fiber and Fire Retardant Viscose Fiber

Journal of Engineered Fibers and Fabrics ◽

10.1177/155892501400900205 ◽

2014 ◽

Vol 9 (2) ◽

pp. 155892501400900

Author(s):

Tao Wang ◽

Xianlin Xu ◽

Yanlin Ren ◽

Songtao Qin ◽

Xiaoyang Sui ◽

...

Keyword(s):

Activation Energy ◽

Three Dimensional ◽

Fire Retardant ◽

Kinetic Mechanism ◽

Viscose Fiber ◽

Heating Rates ◽

Exponential Factor ◽

Air Atmosphere ◽

Fwo Method ◽

Mechanism Function

The thermal decomposition behavior of fire retardant viscose fiber and viscose fiber were studied by thermogravimetric analysis (TGA) under air atmosphere at heating rates of 10, 20, 30 and 40oC/min. The activation energy and pre-exponential factor were calculated by using the Kissinger method, Flynn-Wall-Ozawa (FWO) method and Satava-Sestak method. The results show that the activation energy for the fire retardant viscose fiber calculated by Kissinger and FWO method was 102.51kJ/mol and 103.73kJ/mol, respectively. The activation energy for viscose fiber calculated by Kissinger and FWO method was 103.58 kJ/mol and 104.83kJ/mol, respectively. The kinetic mechanism function of fire retardant viscose fiber was G(α) = [(1+ α)13-1]2 following a kinetic model of three-dimensional diffusion and the kinetic mechanism function of viscose fiber was G(α) = α3/2 following the power function rule.

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Thermogravimetric kinetic analysis of in-situ catalytic pyrolysis of palm oil wastes with the presence of palm oil wastes ash catalyst

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1195/1/012010 ◽

2021 ◽

Vol 1195 (1) ◽

pp. 012010

Author(s):

S W Hii ◽

B L F Chin ◽

C L Yiin ◽

F R S Majing ◽

Z A Jawad ◽

...

Keyword(s):

Activation Energy ◽

Kinetic Analysis ◽

Palm Oil ◽

Oil Palm ◽

Catalytic Pyrolysis ◽

Heating Rates ◽

Exponential Factor ◽

Oil Palm Frond ◽

Palm Frond

Abstract The thermal degradation and kinetic analysis for oil palm frond (OPF) and oil palm trunk (OPT) with its ashes were investigated using thermogravimetric approach (TGA). OPF ash, OPT ash and its mixtures are used as a natural source of catalysts in the pyrolytic conversion of the palm oil wastes to bioenergy. The TGA experiments were conducted in a range of heating rates of 10-100 K/min from the temperature of 323 K to 1173 K. Coats-Redfern model is applied in this study to evaluate the activation energy (EA ) and pre-exponential factor (A). The average EA values ranged 24.27-32.36 kJ.mol−1 and 41.42-46.10 kJ.mol−1 for pyrolysis of OPF and OPT respectively. Meanwhile, the average EA values ranged 24.27-31.06 kJ.mol−1 and 31.77-43.45 kJ.mol−1 for catalytic pyrolysis of OPF and OPT respectively.

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

Processes ◽

10.3390/pr9020195 ◽

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.

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Non-Isothermal Kinetic Analysis of the Crystallization of Metallic Glasses Using the Master Curve Method

Materials ◽

10.3390/ma4122231 ◽

2011 ◽

Vol 4 (12) ◽

pp. 2231-2243 ◽

Cited By ~ 21

Author(s):

Joan Torrens-Serra ◽

Shankar Venkataraman ◽

Mihai Stoica ◽

Uta Kuehn ◽

Stefan Roth ◽

...

Keyword(s):

Kinetic Analysis ◽

Metallic Glasses ◽

Master Curve ◽

Master Curve Method ◽

Curve Method ◽

Isothermal Kinetic Analysis ◽

Isothermal Kinetic

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Studies on the Thermal Decomposition Kinetic of an Nitrate Ester

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.182-183.1575 ◽

2012 ◽

Vol 182-183 ◽

pp. 1575-1580 ◽

Cited By ~ 1

Author(s):

Juan Wang ◽

Da Bin Liu ◽

Xin Li Zhou

Keyword(s):

Activation Energy ◽

Thermal Decomposition ◽

Decomposition Mechanism ◽

Thermal Decomposition Mechanism ◽

Decomposition Kinetic ◽

Heating Rates ◽

Exponential Factor ◽

Nitrate Ester ◽

Dynamic Function ◽

Thermal Decomposition Kinetic

The certain nitrate ester explosive has been tested by TG at the heating rates of 10, 15, 20, 25K•min-1. Basing on the TG experiment results the thermal decomposition activation energy has been calculated by the methods of Ozawa, KAS and iteration. And the thermal decomposition mechanism function of the explosive with 38 kinds of dynamic function was deduced by the method of integration. The results show that the thermal decomposition mechanism of the nitrate ester is chemical reaction mechanism. The thermal decomposition kinetic parameters such as average activation energy Ea and pre-exponential factor A are 133.23×103 J•mol-1 and 3.191×107 s-1 respectively.

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