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

2018 ◽  
Vol 64 (No. 1) ◽  
pp. 41-46 ◽  
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<sup>–1</sup>. 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<sup>–1</sup>, 179.8–188.1 kJ·mol<sup>–1</sup> and 170.1–178.7 kJ·mol<sup>–1</sup> determined by the Friedman, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods, respectively. 

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

2017 ◽  
Vol 20 (2) ◽  
pp. 52-56 ◽  
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.

scholarly journals Thermal Decomposition of Brominated Butyl Rubber

2021 ◽  
Author(s):  
Wei Zhang ◽  
Jinping Xiong ◽  
Yang Zang ◽  
Yanli Lu ◽  
Weisheng Lin ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Isoconversional Method ◽  
Butyl Rubber ◽  
Heating Rates ◽  
Excellent Thermal Stability ◽  
Small Peak ◽  
Air Atmosphere ◽  
Brominated Butyl Rubber ◽  
Derivative Thermogravimetry

The thermal decomposition of brominated butyl rubber under air atmosphere was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG) at various heating rates. The kinetic parameters were evaluated by TG and the isoconversional method developed by Ozawa. One prominent decomposition stage was observed in the DTG curves at high heating rates while an additional small peak was observed at low heating rates. The apparent activation energy determined using the TG method ranged from 219.31&ndash;228.13 kJ&middot;mol-1 at various heating rates. The non-isothermal degradation was found to be a first order reaction, and the activation energy, as determined by the isoconversional method, increased with an increase in mass loss. The kinetic data suggested that brominated butyl rubber had excellent thermal stability. This study will indirectly aid in improving rubber pyrolysis methods and in enhancing the heat resistance of materials.

scholarly journals Thermal Decomposition of Brominated Butyl Rubber

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6767
Author(s):  
Wei Zhang ◽  
Yang Zang ◽  
Yanli Lu ◽  
Weisheng Lin ◽  
Shengyun Zhao ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Isoconversional Method ◽  
Butyl Rubber ◽  
Heating Rates ◽  
Excellent Thermal Stability ◽  
Small Peak ◽  
Air Atmosphere ◽  
Brominated Butyl Rubber ◽  
Derivative Thermogravimetry

The thermal decomposition of brominated butyl rubber under air atmosphere was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG) at various heating rates. The kinetic parameters were evaluated by TG and the isoconversional method developed by Ozawa. One prominent decomposition stage was observed in the DTG curves at high heating rates, while an additional small peak was observed at low heating rates. The apparent activation energy determined using the TG method ranged from 219.31 to 228.13 kJ·mol−1 at various heating rates. The non-isothermal degradation was found to be a first-order reaction, and the activation energy, as determined by the isoconversional method, increased with an increase in mass loss. The kinetic data suggest that brominated butyl rubber has excellent thermal stability. This study can indirectly aid in improving rubber pyrolysis methods and in enhancing the heat resistance of materials.

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 Decomposition Kinetics of Flame Retardant Polybutylene Terephthalate Matrix Composites

2019 ◽  
Vol 956 ◽  
pp. 181-191
Author(s):  
Jian Lin Xu ◽  
Bing Xue Ma ◽  
Cheng Hu Kang ◽  
Cheng Cheng Xu ◽  
Zhou Chen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Flame Retardant ◽  
Mass Loss Rate ◽  
Decomposition Reaction ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Heating Rates ◽  
Polybutylene Terephthalate ◽  
Kinetics Of

The thermal decomposition kinetics of polybutylene terephthalate (PBT) and flame-retardant PBT (FR-PBT) were investigated by thermogravimetric analysis at various heating rates. The kinetic parameters were determined by using Kissinger, Flynn-Wall-Ozawa and Friedman methods. The y (α) and z (α) master plots were used to identify the thermal decomposition model. The results show that the rate of residual carbon of FR-PBT is higher than that of PBT and the maximum mass loss rate of FR-PBT is lower than that of PBT. The values of activation energy of PBT (208.71 kJ/mol) and FR-PBT (244.78 kJ/mol) calculated by Kissinger method were higher than those of PBT (PBT: 195.54 kJ/mol) and FR-PBT (FR-PBT: 196.00 kJ/mol) calculated by Flynn-Wall-Ozawa method and those of PBT and FR-PBT (PBT: 199.10 kJ/mol, FR-PBT: 206.03 kJ/mol) calculated by Friedman methods. There is a common thing that the values of activation energy of FR-PBT are higher than that of PBT in different methods. The thermal decomposition reaction models of the PBT and FR-PBT can be described by Avarami-Erofeyev model (A1).

scholarly journals Hydrothermal Synthesis of Hematite Nanoparticles Decorated on Carbon Mesospheres and Their Synergetic Action on the Thermal Decomposition of Nitrocellulose

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 968 ◽  
Author(s):  
Abdenacer Benhammada ◽  
Djalal Trache ◽  
Mohamed Kesraoui ◽  
Salim Chelouche
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Analytical Techniques ◽  
Decomposition Reaction ◽  
Decomposition Temperature ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Nano Catalyst ◽  
Average Size ◽  
A Minor

In this study, carbon mesospheres (CMS) and iron oxide nanoparticles decorated on carbon mesospheres (Fe2O3-CMS) were effectively synthesized by a direct and simple hydrothermal approach. α-Fe2O3 nanoparticles have been successfully dispersed in situ on a CMS surface. The nanoparticles obtained have been characterized by employing different analytical techniques encompassing Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The produced carbon mesospheres, mostly spherical in shape, exhibited an average size of 334.5 nm, whereas that of Fe2O3 supported on CMS is at around 80 nm. The catalytic effect of the nanocatalyst on the thermal behavior of cellulose nitrate (NC) was investigated by utilizing differential scanning calorimetry (DSC). The determination of kinetic parameters has been carried out using four isoconversional kinetic methods based on DSC data obtained at various heating rates. It is demonstrated that Fe2O3-CMS have a minor influence on the decomposition temperature of NC, while a noticeable diminution of the activation energy is acquired. In contrast, pure CMS have a slight stabilizing effect with an increase of apparent activation energy. Furthermore, the decomposition reaction mechanism of NC is affected by the introduction of the nano-catalyst. Lastly, we can infer that Fe2O3-CMS may be securely employed as an effective catalyst for the thermal decomposition of NC.

Studies on the Thermal Decomposition Kinetic of an Nitrate Ester

2012 ◽  
Vol 182-183 ◽  
pp. 1575-1580 ◽  
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.

Isothermal kinetic analysis of the thermal decomposition of kaolinite: The thermogravimetric study

2010 ◽  
Vol 501 (1-2) ◽  
pp. 24-29 ◽  
Author(s):  
Petr Ptáček ◽  
Dana Kubátová ◽  
Jaromír Havlica ◽  
Jiří Brandštetr ◽  
František Šoukal ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Analysis ◽  
Thermogravimetric Study ◽  
Isothermal Kinetic Analysis ◽  
Isothermal Kinetic

Thermal decomposition of (C6H5-NH3)4Mo8O26 · 2H2O. isothermal and non-isothermal kinetic analysis

1986 ◽  
Vol 98 ◽  
pp. 81-87 ◽  
Author(s):  
C. Santiago ◽  
A.R. Arnaiz ◽  
A. Irabien ◽  
M. Martinez
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Analysis ◽  
Isothermal Kinetic Analysis ◽  
Isothermal Kinetic

The non-isothermal kinetic analysis of the thermal decomposition of kaolinite by thermogravimetric analysis

2010 ◽  
Vol 204 (2-3) ◽  
pp. 222-227 ◽  
Author(s):  
Petr Ptáček ◽  
Dana Kubátová ◽  
Jaromír Havlica ◽  
Jiří Brandštetr ◽  
František Šoukal ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Kinetic Analysis ◽  
Isothermal Kinetic Analysis ◽  
Isothermal Kinetic
Sign in / Sign up

Export Citation Format

Share Document