scholarly journals Comparative Thermal Degradation Behaviors and Kinetic Mechanisms of Typical Hardwood and Softwood in Oxygenous Atmosphere

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1598
Author(s):  
Xiaokang Xu ◽  
Renming Pan ◽  
Ruiyu Chen
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Beech Wood ◽  
Degradation Process ◽  
Heating Rates ◽  
Experimental Profile ◽  
Kinetic Triplet ◽  
Kinetic Mechanisms ◽  
External Conditions ◽  
Degradation Behaviors

In order to utilize woody biomass effectively for bioenergy and chemical feedstocks, the comparative thermal degradation behaviors and kinetic mechanisms of typical hardwood (beech wood) and softwood (camphorwood) were studied at various heating rates in air. The Kissinger-Akahira-Sunose approach combined with the Coats-Redfern approach was employed to estimate the kinetic triplet. Softwood degradation began and ended at lower temperatures than hardwood. Compared with softwood, the maximal reaction rate of hardwood was greater and occurred in the higher temperature region. Two decomposition regions were determined by the variation of activation energy, and the dividing point was α = 0.6 and α = 0.65 for hardwood and softwood, respectively. Moreover, the average activation energy of hardwood was larger than that of softwood during the whole decomposition process. The thermal degradation process occurring in region 1 was dominated by the Avrami-Erofeev and 3D diffusion models for hardwood and softwood, respectively. Furthermore, the kinetic modeling results showed good consistency between the experimental and simulated curves under 5, 15, 20, and 40 K/min. It is noted that the thermogravimetric experimental profile under 20 K/min was not used for estimating the kinetic triplet. Besides, the combustion performance of hardwood is superior to softwood under the same external conditions (heating rate and atmosphere).

Non-isothermal degradation kinetics for polycarbonate/ polymethylphenylsilsesquioxane composites

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiangbo Wang ◽  
Zhong Xin
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Flame Retardancy ◽  
Degradation Kinetics ◽  
Degradation Process ◽  
Nitrogen Atmosphere ◽  
Ozawa Method ◽  
Degradation Behaviors ◽  
Thermal Degradation Process

AbstractThe thermal degradation behaviors of PC/PMPSQ (polymethylphenylsilsesquioxane) systems were investigated by thermogravimetric analysis (TGA) under non-isothermal conditions in nitrogen atmosphere. During non-isothermal degradation, Kissinger and Flynn-Wall-Ozawa methods were used to analyze the thermal degradation process. The results showed that a remarkable decrease in activation energy ( E ) was observed in the early and middle stages of thermal degradation in the presence of PMPSQ, which indicated that the addition of PMPSQ promoted the thermal degradation of PC. Flynn-Wall-Ozawa method further revealed that PMPSQ significantly increased the activation energy of PC thermal degradation in the final stage, which illustrated that the PMPSQ stabilized the char residues and improved the flame retardancy of PC in the final period of thermal degradation process

scholarly journals Thermal Degradation Characteristics and Kinetics of Oxy Combustion of Corn Residues

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Poramate Sittisun ◽  
Nakorn Tippayawong ◽  
Darunee Wattanasiriwech
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Degradation Process ◽  
Similar Magnitude ◽  
Heating Rates ◽  
Decomposition Rates ◽  
Similar Weight ◽  
Thermal Degradation Process ◽  
Kinetics Of ◽  
Corn Residues

Thermogravimetric analysis was used to investigate oxy combustion of corncob and stover. The biomass samples were heated from ambient temperature to 900°C at different heating rates of 10, 30, and 50 K/min. Both biomass samples showed similar weight loss patterns with three zones, corresponding to dehydration, devolatilization, and char combustion, but displayed different degradation temperatures. Increasing heating rate was found to shift the degradation patterns to higher temperatures. Decomposition rates of cob and stover may have been influenced by their lignocellulosic composition. The kinetic parameters of the thermal degradation process were also determined and compared using the Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods. Both methods were found to give similar values and patterns of activation energy against conversion fraction. The average values were found to be in similar magnitude to those reported in the literature, around 170 and 148 kJ/mol for cob and stover, respectively.

INVESTIGATION OF THERMAL DEGRADATION OF POULTRY PROCESSING DEWATERED SLUDGE USING THERMOGRAVIMETRIC ANALYSIS METHOD

2015 ◽  
Vol 76 (5) ◽  
Author(s):  
N. Aniza ◽  
S. Hassan ◽  
M. F. M. Nor ◽  
K. E. Kee ◽  
Aklilu T.
Keyword(s):  
Particle Size ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Heating Rate ◽  
Degradation Process ◽  
Heating Rates ◽  
Initial Stage ◽  
Poultry Processing ◽  
Effect Of Particle Size ◽  
Dewatered Sludge

Thermal degradation of Poultry Processing Dewatered Sludge (PPDS) was studied using thermogravimetric analysis (TGA) method. The effect of particle size on PPDS samples and operational condition such as heating rates were investigated. The non-isothermal TGA was run under a constant flow of oxygen at a rate of 30 mL/min with temperature ranging from 30ºC to 800ºC. Four sample particle sizes ranging between 0.425 mm to 2 mm, and heating rate between 5 K/min to 20 K/min were used in this study. The TGA results showed that particle size does not have any significant effect on the thermogravimetry (TG) curves at the initial stage, but the TG curves started to separate explicitly at the second stage. Particle size may affect the reactivity of sample and combustion performance due to the heat transfer and temperature gradient. The TG and peak of derivative thermogravimetry (DTG) curves tend to alter at high temperature when heating rate is increased most likely due to the limitation of mass transfer and the delay of degradation process. 

Characterization and thermal degradation kinetics of thermoplastic polyimide based on BAPP

2017 ◽  
Vol 30 (7) ◽  
pp. 787-793 ◽  
Author(s):  
Xu Su ◽  
Yong Xu ◽  
Linshuang Li ◽  
Chaoran Song
Keyword(s):  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Degradation Process ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Step Method ◽  
Nitrogen Derivative ◽  
Degradation Reaction ◽  
Kinetics Of

Two kinds of thermoplastic polyimides (PIs) were synthesized via a two-step method with 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 4,4′-oxydianiline (ODA) diamine, and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), and their thermal degradation kinetics was studied by thermogravimetric analysis at different heating rates under nitrogen. Derivative thermogravimetric analysis curves indicated a simple, single-stage degradation process in PI BTDA-BAPP and a two-stage degradation process in PI BTDA-ODA-BAPP. The activation energies ( Eas) of the thermal degradation reaction were determined by the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose methods without a knowledge of the kinetic reaction mechanism. By comparing the values of Ea and weight loss temperatures, it was demonstrated that the thermal stability of PI BTDA-ODA-BAPP was superior to that of PI BTDA-BAPP.

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.

scholarly journals Comparative study of the reaction kinetics of three residual biomasses

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2891-2905
Author(s):  
Arnaldo Martinez ◽  
Lourdes Meriño ◽  
Alberto Albis ◽  
Jorge Ortega
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Lignin Content ◽  
Cellulose Degradation ◽  
Calorific Value ◽  
Degradation Process ◽  
Proximate Analysis ◽  
Cellulose Content ◽  
Heating Rates ◽  
Biomass Residues

Kinetic analysis for the combustion of three agro-industrial biomass residues (coconut husk, corn husk, and rice husk) was carried out in order to provide information for the generation of energy from them. The analysis was performed using the results of the data obtained by thermogravimetric analysis (TGA) at three heating rates (10, 20, and 30 K/min). The biomass residues were characterized in terms of proximate analysis, elemental analysis, calorific value, lignin content, α-cellulose content, hemicellulose content, and holocellulose content. The biomass fuels were thermally degraded in an oxidative atmosphere. The results showed that the biomass thermal degradation process is comprised of the combustion of hemicellulose, cellulose, and lignin. The kinetic parameters of the distributed activation energy model indicated that the activation energy distribution for the pseudocomponents follows lignin, cellulose, and hemicellulose in descending order. The activation energy values for each set of reactions are similar between the heating rates, which suggests that it is independent of the heating rate between 10 K/min and 30 K/min. For all the biomass samples, the increased heating rate resulted in the overlap of the hemicellulose and cellulose degradation events.

scholarly journals DTA Evaluation of Spruce Wood Degradation Process

2017 ◽  
Vol 25 (40) ◽  
pp. 41-48
Author(s):  
Ivan Hrušovský ◽  
Peter Rantuch ◽  
Jozef Martinka ◽  
Simona Dzíbelová
Keyword(s):  
Activation Energy ◽  
Room Temperature ◽  
Degradation Process ◽  
Heating Rates ◽  
Wood Degradation ◽  
Wood Sawdust ◽  
Spruce Wood ◽  
Calculated Activation Energy ◽  
Two Stages ◽  
Calculated Activation

Abstract The decomposition stages of spruce wood sawdust were analyzed by means of sequential differential calorimetry. Two stages of decomposition were identified and activation energy of one stage was calculated using the Kissinger method. The DTA was conducted by means of SEDEX safety calorimeter. Sample was analyzed under three heating rates of 10, 20 and 45 °C/h in temperature range from room temperature to 400 °C. The calculated activation energy for the last and most clear decomposition peak was 122.63 KJ/mol. The results are comparable with the data calculated by J.V. Rissanen et al., who calculated activation energy for Spruce hemicellulose as 120 KJ/mol.

scholarly journals Devolatilization of African Palm (Elaeis guineensis) Husk studied by TG-MS

2018 ◽  
Vol 38 (2) ◽  
pp. 9-17
Author(s):  
Alberto Ricardo Albis Arrieta ◽  
Ever Ortiz Muñoz ◽  
Ismael Piñeres Ariza ◽  
Andrés Felipe Suárez Escobar ◽  
Marley Cecilia Vanegas Chamorro
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Mass Spectroscopy ◽  
Elaeis Guineensis ◽  
Degradation Process ◽  
Pyrolysis Process ◽  
Distributed Activation Energy Model ◽  
Evolved Gas ◽  
Secondary Reactions ◽  
Thermal Degradation Process

 Using simultaneous thermogravimetrical analysis coupled with mass spectroscopy, the pyrolysis of African palm husk, using several heat rates and programs was performed. Seven relations of mass/charge were followed of the evolved gas of the pyrolysis process, fitting the kinetics and the mass spectroscopy signals to the distributed activation energy model (DAEM) with different numbers of pseudo-components. Fitting with four pseudo-components proved to be the best for modeling the thermal degradation process. Kinetic parameters were not affected by the heating rate or program employed, which agrees with other reports for similar biomass. Methane, methanol formaldehyde, furfural were successfully fitted to the DAEM model, nevertheless CO2 and NO2 were not able to be represented by this model due to its production in secondary reactions in gaseous phase.

Study on Thermal Degradation and Kinetic of Microencapsulated Red Phosphorus (MRP)/High Density Polyethylene (HDPE) Composite

2020 ◽  
Vol 842 ◽  
pp. 98-104
Author(s):  
Jia Li ◽  
Hui Wang ◽  
Zhong Han Li ◽  
Ting Ting Zhao ◽  
Tian Tian Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
High Density Polyethylene ◽  
Degradation Rate ◽  
Degradation Mechanism ◽  
High Density ◽  
Red Phosphorus ◽  
Heating Rates ◽  
Ikp Method

Thermal degradation of the composite constituted by high density polyethylene (HDPE) and microencapsulated red phosphorus (MRP) were studied using thermogravimetric (TG) data obtained at different heating rates. The kinetic models and parameters of the thermal degradation of MRP/HDPE composite were evaluated by FWO, KAS and IKP method. It indicates that the activation energy E of 4 % MRP/HDPE composite is higher than HDPE for three methods. MRP could improve the thermal stability and slow down the thermal degradation of HDPE. With adding MRP, the degradation mechanism of HDPE is changed and the degradation rate decreases.

Effect of Pd Nanoparticle on the Thermal Degradation Kinetics of Nylon 6/Pd Nanocomposite Prepared by a Dry Process

2012 ◽  
Vol 486 ◽  
pp. 27-33 ◽  
Author(s):  
Jae Young Lee ◽  
Sung Wan Hong ◽  
Kyeong Sik Han ◽  
Taeck Hong Lee ◽  
Hong Ki Lee
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Pd Nanoparticles ◽  
Nylon 6 ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Dry Process ◽  
Effect Of Pd ◽  
Kinetics Of

Palladium (Pd) nanoparticles were incorporated into a nylon 6 film via a dry process which consisted of simultaneous vaporization, penetration and reduction processes of palladium (II) bis (acetylacetonate, Pd (acac)2) at 180°C for various exposure time. The even dispersion of the generated Pd nanoparticles were observed by transmission electron microscope (TEM) and the Pd loading weight of about 15~43 wt% was measured by thermogravimetric analysis (TGA). In order to study the catalytic effect of Pd nanoparticles on the thermal degradation kinetics of nylon 6, TGA data at various heating rates were introduced to Flynn & Wall equation. The thermal degradation activation energy for neat nylon 6 was ca. 162~178 kJ/mol over the thermal degradation fraction of 0.05~0.40 while that of the nylon 6/Pd (26.5 wt%) nanocomposite was ca. 110~169 kJ/mol over the same fraction range. It meant the Pd nanoparticles were acted as a catalyst on the depolymerization of amide group in nylon 6. It was also found that the activation energy decreased slightly with the increasing Pd loading weight.

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