scholarly journals Nonisothermal Thermogravimetric Analysis of Thai Lignite with High CaO Content

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Pakamon Pintana ◽  
Nakorn Tippayawong
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Combustion Kinetics ◽  
Heating Rates ◽  
Thermogravimetric Method ◽  
Degradation Behaviors ◽  
Fwo Method ◽  
Free Cao ◽  
Kinetics Of

Thermal behaviors and combustion kinetics of Thai lignite with different SO3-free CaO contents were investigated. Nonisothermal thermogravimetric method was carried out under oxygen environment at heating rates of 10, 30, and 50°C min−1from ambient up to 1300°C. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods were adopted to estimate the apparent activation energy (E) for the thermal decomposition of these coals. Different thermal degradation behaviors were observed in lignites with low (14%) and high (42%) CaO content. Activation energy of the lignite combustion was found to vary with the conversion fraction. In comparison with the KAS method, higherEvalues were obtained by the FWO method for all conversions considered. High CaO lignite was observed to have higher activation energy than the low CaO coal.

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 Modelling of Thermal Decomposition Kinetics of Proteins, Carbohydrates and Lipids Using Scenedesmus microalgae thermal Data

2020 ◽  
Vol 32 (11) ◽  
pp. 2921-2926
Author(s):  
BOTHWELL NYONI ◽  
PHUTI TSIPA ◽  
SIFUNDO DUMA ◽  
SHAKA SHABANGU ◽  
SHANGANYANE HLANGOTHI
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Bulk Material ◽  
Decomposition Kinetics ◽  
Second Order ◽  
Thermal Decomposition Kinetics ◽  
Heating Rates ◽  
High Heating ◽  
The Individual ◽  
Kinetics Of

In present work, the thermal decomposition behaviour and kinetics of proteins, carbohydrates and lipids is studied by use of models derived from mass-loss data obtained from thermogravimetric analysis of Scenedesmus microalgae. The experimental results together with known decomposition temperature range values obtained from various literature were used in a deconvolution technique to model the thermal decomposition of proteins, carbohydrates and lipids. The models fitted well (R2 > 0.99) and revealed that the proteins have the highest reactivity followed by lipids and carbohydrates. Generally, the decomposition kinetics fitted well with the Coats-Redfern first and second order kinetics as evidenced by the high coefficients of determination (R2 > 0.9). For the experimental conditions used in this work (i.e. high heating rates), the thermal decomposition of protein follows second order kinetics with an activation energy in the range of 225.3-255.6 kJ/mol. The thermal decomposition of carbohydrate also follows second order kinetics with an activation energy in the range of 87.2-101.1 kJ/mol. The thermal decomposition of lipid follows first order kinetics with an activation energy in the range of 45-64.8 kJ/ mol. This work shows that the thermal decomposition kinetics of proteins, carbohydrates and lipids can be performed without the need of experimentally isolating the individual components from the bulk material. Furthermore, it was shown that at high heating rates, the decomposition temperatures of the individual components overlap resulting in some interactions that have a synergistic effect on the thermal reactivity of carbohydrates and lipids.

Thermogravimetric Analysis of KCl-Pretreated Soybean Stalk

2015 ◽  
Vol 1092-1093 ◽  
pp. 118-121
Author(s):  
Dong Yu Chen ◽  
Qing Yu Liu
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Metal Salts ◽  
Pyrolysis Kinetics ◽  
Ozawa Method ◽  
Heating Rates ◽  
Energy Value ◽  
Lower Activation ◽  
Higher Temperature ◽  
Kinetics Of

To study the influence of KCl pretreating on the pyrolysis kinetics of soybean stalk, the pyrolysis of soybean stalk pretreated by different concentration KCl solutions were performed by nonisothermal thermogravimetric analysis (TGA) at five different heating rates. The Ozawa method was employed to calculate the activation energy. The results showed that the pyrolysis process of the soybean stalk pretreated by 3% and 10% KCl solution can be separated into four stages (water loss, depolymerization and vitrification, thermal decomposition, and carbonization). With the heating rate increasing, the main pyrolysis zone of the TG (thermogravimetric) and DTG curves move to the higher temperature region, and the maximum pyrolysis rate and its corresponding temperature increase too. A small amount of metal salts addition is conducive to the formation of volatile, and a certain amount of metal salts can improve the charcoal yield. More KCl additive makes the lower activation energy value, and the obtained activation energy value increases with the reaction degree.

scholarly journals Desorption characteristics and kinetic parameters determination of molecular sieve by thermogravimetric analysis/differential thermogravimetric analysis technique

2018 ◽  
Vol 36 (7-8) ◽  
pp. 1389-1404 ◽  
Author(s):  
Yalou Guo ◽  
Hui Zhang ◽  
Yingshu Liu
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Heating Rates ◽  
Carrier Gas ◽  
Zeolite 13X ◽  
Analysis Technique ◽  
Desorption Activation Energy ◽  
Differential Thermogravimetric Analysis ◽  
Kinetics Of

The kinetics of the thermal desorption of CO2 adsorbed on zeolite 13X were obtained using a differential thermogravimetric analyser under two different carrier gas conditions. The varying heating rates were set as 8, 12, 16, and 20 K min−1, respectively. The desorption activation energy of the physisorption sites for this experiment evaluated by an integral method without prediction of the reaction order ranged from 12.15 to 14.12 kJ mol−1 (CO2 as the carrier gas) and 43.32 to 50.42 kJ mol−1 (Ar as the carrier gas), respectively. The desorption activation energy of the chemisorption sites ranged from 57.95 to 58.53 kJ mol−1 (CO2 as the carrier gas) and 74.02 to 79.92 kJ mol−1 (Ar as the carrier gas), respectively.

Thermal degradation kinetics of oxo-degradable PP/PLA blends

2018 ◽  
Vol 39 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Dev K. Mandal ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Kinetic Parameters ◽  
Degradation Kinetics ◽  
Nitrogen Atmosphere ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Kinetics Of

AbstractIn this article, the influence of polylactide and pro-oxidant on the thermal stability, degradation kinetics, and lifetime of polypropylene has been investigated using thermogravimetric analysis under nitrogen atmosphere at four different heating rates (i.e. 5, 10, 15, and 20°C/min). The kinetic parameters of degradation were studied over a temperature range of 30–550°C. The derivative thermogravimetric curves have indicated single stage and two stage degradation processes. The activation energy was evaluated by using the Kissinger, Kim-Park, and Flynn-Wall methods under the nitrogen atmosphere. The activation energy value of polypropylene was much higher than that of polylactide. Addition of polylactide and pro-oxidant in polypropylene decreased the activation energy. The lifetime of polypropylene has also decreased with the addition of polylactide and pro-oxidant.

Decomposition Kinetics of Switchgrass: Estimating Activation Energy

2014 ◽  
Vol 881-883 ◽  
pp. 726-733
Author(s):  
Gui Ying Xu ◽  
Jiang Bo Wang ◽  
Ling Ping Guo ◽  
Guo Gang Sun
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Apparent Activation Energy ◽  
High Purity ◽  
Isoconversional Methods ◽  
Decomposition Kinetics ◽  
Heating Rates ◽  
Model Free ◽  
Chemical Utilization ◽  
Kinetics Of

TG analysis was used to investigate the thermal decomposition of switchgrass, which is a potential gasification feedstock. 10 mg switchgrass sample with the particles between 0.45 and 0.70 mm was linearly heated to 873 K at heating rates of 10, 20, 30 K/min, respectively, under high-purity nitrogen. The Kissinger method and three isoconversional methods including Friedman, Flynn-wall-Ozawa, Vyazovkin and Lenikeocink methods were used to estimate the apparent activation energy of switchgrass. With the three isoconversional methods, it can be concluded that the activation energy increases with increasing conversion. The four model free methods reveal activation energies in the range of 70-460 kJ/mol. These activation energy values provide the basic data for the thermo-chemical utilization of the switchgrass.

scholarly journals Decomposition Characteristics and Kinetics of Microalgae in N2 and CO2 Atmospheres by a Thermogravimetry

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Xu Qing ◽  
Ma Xiaoqian ◽  
Yu Zhaosheng ◽  
Cai Zilin ◽  
Ling Changming
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Apparent Activation Energy ◽  
Kinetic Parameters ◽  
Reaction Order ◽  
Heating Rates ◽  
Residual Mass ◽  
Second Stage ◽  
Kinetics Of

The thermal degradation characteristics of microalgae were investigated in highly purified N2 and CO2 atmospheres by a thermogravimetric analysis (TGA) under different heating rates (10, 20, and 40°C/min). The results indicated that the total residual mass in CO2 atmosphere (16.86%) was less than in N2 atmosphere (23.12%); in addition, the kinetics of microalgae in N2 and CO2 atmospheres could be described by the pseudo bicomponent separated state model (PBSM) and pseudo-multi-component overall model (PMOM), respectively. The kinetic parameters calculated by Coats-Redfern method showed that, in CO2 atmosphere, the apparent activation energy (E) of microalgae was between 9.863 and 309.381 kJ mol−1 and the reaction order (n) was varied from 1.1 to 7. The kinetic parameters (E,n) of the second stage in CO2 atmosphere were quite similar to those in N2 atmosphere.

scholarly journals Distributed Activation Energy Model for Thermal Decomposition of Polypropylene Waste

2021 ◽  
pp. 179-187
Author(s):  
S. Kartik ◽  
Hemant K. Balsora ◽  
Abhishek Sharma ◽  
Anand G. Chakinala ◽  
Abhishek Asthana ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Energy Model ◽  
Decomposition Kinetics ◽  
Fuel Oil ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Distributed Activation Energy Model ◽  
Municipal Plastic Waste ◽  
Kinetics Of

AbstractThermal decomposition kinetics of Polypropylene (PP) waste is extremely important with respect to valorisation of waste plastics and production of utilizable components viz. chemicals, fuel oil & gas. The present research study focuses on pyrolysis kinetics of PP waste, which is present as a fraction of municipal plastic waste through distributed activation energy model (DAEM). The decomposition kinetics for PP follows a Gaussian distribution, where the normal distribution curves were centred corresponding to activation energy of 224 kJ/mol. The standard deviation of the distribution for the PP sample was found to be 22 kJ/mol indicating its wider distribution of decomposition range. The data validation has been carried out by comparing the rate parameter and extent of conversion values calculated through DAEM model with the Thermogravimetric analysis (TGA) experiments carried out for PP at various heating rates of 5, 10, 20 and 40 °C/min.

scholarly journals Oxygen-enriched combustion of lignite

2015 ◽  
Vol 19 (4) ◽  
pp. 1389-1392 ◽  
Author(s):  
Yong-Feng Zhang ◽  
Xiang-Yun Chen ◽  
Qian-Cheng Zhang ◽  
Chun-Ping Li ◽  
Quan Zhou
Keyword(s):  
Activation Energy ◽  
Kinetic Parameter ◽  
Oxygen Concentration ◽  
Combustion Kinetics ◽  
Ozawa Method ◽  
Heating Rates ◽  
Thermogravimetric Analyzer ◽  
Kinetics Of

The study is concerned on the oxygen-enriched combustion kinetics of lignite. Thermogravimetric experiments were carried out in a thermogravimetric analyzer under O2/N2 conditions, and operated at different heating rates ranging from 5?C per minute to 25?C per minute. Flynn-Wall-Ozawa method was used to calculate the kinetic parameter. The value of activation energy increased when the oxygen concentration varied from 21% to 70%.

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