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

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.

Study on the Pyrolysis Characteristics and Mechanism of KCl-Pretreated Sunflower Stalk

2013 ◽  
Vol 448-453 ◽  
pp. 1665-1674
Author(s):  
Dong Yu Chen ◽  
Qing Yu Liu ◽  
Yan Qing Hu
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Three Dimensional ◽  
Kinetic Mechanism ◽  
Metal Salts ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Energy Value ◽  
Pyrolysis Characteristics ◽  
Mechanism Model

To study the influence of KCl pretreating on the pyrolysis kinetics of sunflower stalk, the pyrolysis of sunflower stalk pretreated by different concentration KCl solutions were performed by nonisothermal thermogravimetric analysis (TGA) at five different heating rates. The Ozawa and Kissinger methods were employed to calculate the activation energy and the Šatava method was used to obtain the kinetic mechanism model. The results showed that the pyrolysis process of the sunflower 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 direction, and the maximum pyrolysis rate and its corresponding temperature increase too. Adding a small amount of metal salts 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 heating rate increasing. By means of the Šatava method, the kinetic mechanism model for the pyrolysis of KCl-pretreated sunflower stalk is Zhuralev-Lesakin-Tempelman equation, which is three-dimensional diffusion.

scholarly journals Thermal Decomposition Mechanism of GIS Basin Insulator and Kinetic Parameters-Based Lifetime Prediction Methodology

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 653
Author(s):  
Peng Ren ◽  
Qingmin Li ◽  
Honglei Liu ◽  
Yunpeng Li ◽  
Peng Peng ◽  
...  
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Kinetic Parameters ◽  
Thermal Decomposition Mechanism ◽  
Heating Rates ◽  
Computational Accuracy ◽  
Exponential Factor ◽  
Analysis Experiment ◽  
Mechanism Function ◽  
Pyrolysis Kinetic

To reliably detect the latent defects and accurately evaluate the remaining life of gas insulated switchgear (GIS) basin insulators, more effective detection and characterization methods need to be explored. The study of pyrolysis kinetic parameters based on the intrinsic characteristics of materials provides a new way to solve this problem. First, an integral expression model of the reaction mechanism function with four parameters is proposed in this paper, which can represent various existing reaction mechanism functions with better universality and more application fields. Then, on the basis of the temperature transformation equation, an improved method for calculating the activation energy is presented, which shows higher computational accuracy than the existing methods. Further, based on a non-isothermal kinetic equation, the structure of the experimental function is given. It is a method for solving the pyrolysis reaction mechanism function of insulating materials, which can also be used to calculate the pre-exponential factor simultaneously. The thermogravimetric analysis experiment is carried out on a certain basin insulator sample at different heating rates. The pyrolysis kinetic state parameters, including the activation energy, reaction mechanism function and pre-exponential factor of the basin insulator, are calculated. Finally, the life prediction method of basin insulators is established, and the key factors affecting the life of insulators are discussed.

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.

Kinetic Study on Pyrolysis of Gentamicin Residue

2014 ◽  
Vol 955-959 ◽  
pp. 2803-2808
Author(s):  
Ren Ping Liu ◽  
Rui Yao ◽  
Hui Li
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Thermochemical Conversion ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Thermogravimetric Analyzer ◽  
Basic Work ◽  
Mechanism Function ◽  
Kinetics Of

Gentamicin bacteria residue contains high organic compound. The technology of thermochemical conversion can effectively solve the problem of bulk gentamicin residue disposal, research on pyrolysis kinetics of the reaction is the basic work for thermochemical conversion . In this paper, Pyrolysis experiments were carried out in a thermogravimetric analyzer under inert conditions and operated at different heating rates (5, 10, 20 K/min).Two different kinetic models, the iso-conversional Ozawa–Flynn–Wall (Ozawa) models and Satava method were applied on TGA data of gentamicin residue to calculate the kinetic parameters including activation energy, pre-exponential factor and Mechanism function. The results showed that: gentamicin bacteria residue lost most weight of it between 100-650 °C , about 74.23% of the whole sample can decompose under high temperature. The pyrolysis function for gentamicin residue should be G(α) =[-ln(1-α)]3.

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.

A Kinetic Study of Co-Pyrolysis of Coal and Spent Mushroom Compost (SMC)

2013 ◽  
Vol 781-784 ◽  
pp. 2406-2410 ◽  
Author(s):  
Zhi Qiang Wu ◽  
Shu Zhong Wang ◽  
Qi Xing Guo ◽  
Jun Zhao ◽  
Lin Chen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Chemical Compounds ◽  
Initial Step ◽  
Mass Ratio ◽  
Intensive Study ◽  
Heating Rates ◽  
Mushroom Compost ◽  
Spent Mushroom Compost ◽  
Pyrolysis Characteristics ◽  
Fwo Method

Co-utilization of coal and biomass has been shown as an effective way to reduce the carbon footprint. Pyrolysis technology not only transform carbonaceous materials such as coal and biomass into various chemical compounds and fuels, but also as the initial step of the thermochemical conversation. For the sake of a better understanding of the co-thermal conversation, it is very necessary to get a intensive study on the co-pyrolysis of coal and biomass. In this paper the co-pyrolysis characteristics of coal and spent mushroom compost (SMC) were investigated through an thermogravimetry analyzer from ambient temperature to 950 °C at different heating rates (10, 20 and 40 °C/min) under nitrogen condition. Kinetic parameters were determined by the by the Flynn-Wall-Ozawa (FWO) method. It was found that the activation energy decreased with the increasing of the biomass mass ratio, but with the biomass ratio reached 0.75 the activation energy increased again. This may be involved with the negative synergies between the biomass and coal. The results could provide useful information for the further study on the co-pyrolysis of coal and MSC.

scholarly journals Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

2015 ◽  
Vol 60 (2) ◽  
pp. 1357-1359 ◽  
Author(s):  
Y. Hongbo ◽  
C. Meiling ◽  
W. Xu ◽  
G. Hong
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Layered Double Hydroxides ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Exponential Factor ◽  
Thermal Kinetic Parameters ◽  
Double Hydroxides ◽  
Kinetics Of ◽  
Dsc Curves

Abstract The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs) was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC) methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min) on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

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.

A Kinetic Study of Wetland Plant Suaeda salsa L. Pyrolysis Using Thermogravimetric Analyzer

2013 ◽  
Vol 848 ◽  
pp. 126-130
Author(s):  
Hua Xiao Yan ◽  
Hui Zhao ◽  
Qi Liu ◽  
Yan Xiang Ai ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Three Dimensional ◽  
Nitrogen Atmosphere ◽  
Suaeda Salsa ◽  
Good Prospect ◽  
Heating Rates ◽  
Thermogravimetric Analyzer ◽  
Exponential Factors ◽  
Pyrolysis Feedstock ◽  
Diffusion Function

The Suaeda salsa L. has been discovered to be a great potential as a new kind of renewable energy. The pyrolytic characteristics and kinetics of S. salsa were investigated at heating rates of 5, 10, 20, 30°C/min under nitrogen atmosphere respectively. The most probable mechanism function was deduced using Popescu method, which is a three-dimensional diffusion function (), and n=-2/3. Activation energy and pre-exponential factors were studied through the FWO, KAS and Popescu methods. The results showed that the activation energy increase as the pyrolysis process and three stages were observed in the TG-DTG curves of S.salsa. The results showed that S.salsa as a pyrolysis feedstock has a great potential and a good prospect in bio-oil production.

scholarly journals Thermodynamic model and kinetic compensation effect of oil sludge pyrolysis based on thermogravimetric analysis

2020 ◽  
pp. 350-350
Author(s):  
Hui Liu ◽  
Chenglang Xiang ◽  
Jie Mu ◽  
Jieyu Yao ◽  
Dong Ye ◽  
...  
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Compensation Effect ◽  
Thermodynamic Characteristics ◽  
Oil Sludge ◽  
High Heating Rate ◽  
Thermodynamic Models ◽  
Heating Rates ◽  
Kinetic Compensation Effect ◽  
Exponential Factor

Oil sludge (OS) is an organic solid waste in the petrochemical industry and improper treatment of OS will cause environmental pollution. Pyrolysis is an effective way to realize its resource reuse. In order to understand the pyrolysis behavior and thermodynamic characteristics of OS, four OS samples from storage tanks were used as the research object, and pyrolysis experiments were carried out at heating rates of 5, 10, and 15?/min under a nitrogen atmosphere. The kinetic parameters of pyrolysis of OS are calculated by three equal conversion methods (Friedman method (FR), Flynn-Wall-Ozawa method (FWO) and Distributed activation energy model (DAEM)), and the most possible thermodynamic models for the main pyrolysis phase were analyzed and discussed by introducing the Malek method. The results show: High heating rate can promote the pyrolysis of OS; In the pyrolysis stage, the apparent activation energy increases with the increase of the conversion rate. The apparent activation energy calculated by the FR method is more reliable. The average apparent activation energies of the four OS are 221.23, 84.71, 94.67 and 116.56 kJ/mol, respectively. The apparent activation energy and the pre-exponential factor are positively correlated, indicating that there is a kinetic compensation effect in the pyrolysis process. The thermodynamic models of the four OS samples are all three-dimensional diffusion models, but their integral functions are different. The research results can provide theoretical support for the industrialization, harmlessness and resource utilization of OS pyrolysis.

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