scholarly journals Kinetic analysis of the termal decomposition of colombian vacuum residua by termogravimetry

2015 ◽  
Vol 35 (3) ◽  
pp. 19-26 ◽  
Author(s):  
Fabian Andrey Diaz Mateus ◽  
Arlex Chaves ◽  
Maria Paola Maradei ◽  
David Alfredo Fuentes ◽  
Alexander Guzman ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Analysis ◽  
Reaction Order ◽  
Calculated Data ◽  
Reaction Model ◽  
Vacuum Residue ◽  
Font Size ◽  
Heating Rates ◽  
Thermogravimetric Analyzer ◽  
Single Reaction

<p style="margin: 0cm 0cm 0pt; text-align: justify; line-height: normal;"><span style="letter-spacing: -0.1pt; font-family: 'Century Gothic','sans-serif'; font-size: 8pt; mso-bidi-font-size: 9.5pt; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: Arial; mso-fareast-language: ES; mso-bidi-language: EN-US;">Five different Colombian vacuum residues were thermally decomposed in a thermogravimetric analyzer. Three heating rates were employed to heat the sample up to 650°C. The kinetic analysis was performed by the Coats-Redfern method to describe the non-isothermal pyrolysis of the residua, a reaction model where the reaction order gradually increases from first to second order is proposed and an excellent agreement of the experimental with the calculated data is presented. The results also indicate that the pyrolysis of a vacuum residue cannot be modeled by a single reaction mechanism.</span></p>

scholarly journals Kinetic Analysis of the Thermal Degradation of Recycled Acrylonitrile-Butadiene-Styrene by non-Isothermal Thermogravimetry

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 281 ◽  
Author(s):  
Rafael Balart ◽  
David Garcia-Sanoguera ◽  
Luis Quiles-Carrillo ◽  
Nestor Montanes ◽  
Sergio Torres-Giner
Keyword(s):  
Thermal Degradation ◽  
Kinetic Analysis ◽  
Acrylonitrile Butadiene Styrene ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Integral Model ◽  
Heating Rates ◽  
Exponential Factor ◽  
Model Free ◽  
Butadiene Styrene

This work presents an in-depth kinetic study of the thermal degradation of recycled acrylonitrile-butadiene-styrene (ABS) polymer. Non-isothermal thermogravimetric analysis (TGA) data in nitrogen atmosphere at different heating rates comprised between 2 and 30 K min−1 were used to obtain the apparent activation energy (Ea) of the thermal degradation process of ABS by isoconversional (differential and integral) model-free methods. Among others, the differential Friedman method was used. Regarding integral methods, several methods with different approximations of the temperature integral were used, which gave different accuracies in Ea. In particular, the Flynn-Wall-Ozawa (FWO), the Kissinger-Akahira-Sunose (KAS), and the Starink methods were used. The results obtained by these methods were compared to the Kissinger method based on peak temperature (Tm) measurements at the maximum degradation rate. Combined Kinetic Analysis (CKA) was also carried out by using a modified expression derived from the general Sestak-Berggren equation with excellent results compared with the previous methods. Isoconversional methods revealed negligible variation of Ea with the conversion. Furthermore, the reaction model was assessed by calculating the characteristic and functions and comparing them with some master plots, resulting in a nth order reaction model with n = 1.4950, which allowed calculating the pre-exponential factor (A) of the Arrhenius constant. The results showed that Ea of the thermal degradation of ABS was 163.3 kJ mol−1, while ln A was 27.5410 (A in min−1). The predicted values obtained by integration of the general kinetic expression with the calculated kinetic triplet were in full agreement with the experimental data, thus giving evidence of the accuracy of the obtained kinetic parameters.

scholarly journals Pyrolysis kinetics and thermal decomposition behavior of polycarbonate - a TGA-FTIR study

2014 ◽  
Vol 18 (3) ◽  
pp. 833-842 ◽  
Author(s):  
Esin Apaydin-Varol ◽  
Sevgi Polat ◽  
Ayse Putun
Keyword(s):  
Activation Energy ◽  
Fourier Transform ◽  
Reaction Order ◽  
Fourier Transform Infrared ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Thermogravimetric Analyzer ◽  
Fourier Transform Infrared Spectrometer ◽  
Infrared Spectrometer

This study covers the thermal degradation of polycarbonate by means of Thermogravimetric Analyzer coupled with Fourier transform infrared spectrometer (TGA-FTIR). Thermogravimetric analysis of polycarbonate was carried out at four different heating rates of 5, 10, 15, and 20?C per minute from 25?C to 1000?C under nitrogen atmosphere. The results indicated that polycarbonate was decomposed in the temperature range of 425-600?C. The kinetic parameters, such as activation energy, pre-exponential factor and reaction order were determined using five different kinetic models; namely Coast-Redfern, Friedman, Kissinger, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS). Overall decomposition reaction order was determined by Coats-Redfern method as 1.5. Average activation energy was calculated as 150.42, 230.76, 216.97, and 218.56 kJ/mol by using Kissinger, Friedman, FWO, and KAS models, respectively. Furthermore, the main gases released during the pyrolysis of polycarbonate were determined as CO2, CH4, CO, H2O, and other lower molecular weight hydrocarbons such as aldehydes, ketones and carbonyls by using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer.

scholarly journals Application of a New Statistical Model for the Description of Solid Fuel Decomposition in the Analysis of Artemisia apiacea Pyrolysis

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5789
Author(s):  
Tianbao Gu ◽  
Torsten Berning ◽  
Chungen Yin
Keyword(s):  
Experimental Data ◽  
Reaction Mechanism ◽  
Statistical Model ◽  
Solid Fuel ◽  
Conversion Rate ◽  
Reaction Model ◽  
Thermochemical Conversion ◽  
Conversion Degree ◽  
Heating Rates ◽  
Artemisia Apiacea

Pyrolysis, one of the key thermochemical conversion technologies, is very promising to obtain char, oil and combustible gases from solid fuels. Kinetic modeling is a crucial method for the prediction of the solid conversion rate and analysis of the pyrolysis process. We recently developed a new statistical model for the universal description of solid fuel decomposition, which shows great potential in studying solid fuel pyrolysis. This paper demonstrates three essential applications of this new model in the analysis of Artemisia apiacea pyrolysis, i.e., identification of the conversion rate peak position, determination of the reaction mechanism, and evaluation of the kinetics. The results of the first application show a very good agreement with the experimental data. From the second application, the 3D diffusion-Jander reaction model is considered as the most suitable reaction mechanism for the description of Artemisia stem pyrolysis. The third application evaluates the kinetics of Artemisia stem pyrolysis. The evaluated kinetics vary with the conversion degree and heating rates, in which the activation energies and pre-exponential factors (i.e., lnA vs. Ea) show a linear relationship, regardless of the conversion and heating rates. Moreover, the prediction of the conversion rate using the obtained kinetics shows an excellent fit with the experimental data.

scholarly journals Kinetic Analysis of Pyrolysis and Thermo-Oxidative Decomposition of Tennis String Nylon Wastes

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7564
Author(s):  
Haibo Wan ◽  
Zhen Huang
Keyword(s):  
Thermal Degradation ◽  
Kinetic Analysis ◽  
Model Fitting ◽  
Degradation Process ◽  
Nylon 6 ◽  
Reaction Model ◽  
Heating Rates ◽  
Model Free ◽  
Order Chemical Reaction ◽  
First Order Chemical Reaction

Thermal degradation of nylon-6 tennis string nylon wastes in inert nitrogen and air atmospheres was investigated by means of multiple heating-rate thermogravimetric analyses. The results obtained under the heating rates of 5–20 K/min are compared in terms of degradation feature and specific temperature for two atmospheres. Using nonisothermal data, kinetic analysis was thoroughly conducted using various isoconversional model-free methods, including Starink, Madhusudanan–Krishnan–Ninan, Tang, Coats–Redfern, and Flynn–Wall–Ozawa methods. With these kinetic analysis methods, the activation energy over the entire degradation process was successfully calculated. By means of the model-fitting master-plots method, the first-order chemical reaction model was determined to be the most appropriate mechanism function for describing pyrolysis and oxidative thermal degradation of nylon-6 waste. Using kinetic parameters, satisfactory matching against experimental data resulted using the Coats–Redfern method for both cases. Furthermore, thermodynamic parameters such as changes in entropy, enthalpy, and Gibbs free energy during thermal degradation processes were evaluated.

The Kinetic Analysis of Biomass Burning Based on Two-Component Reaction Model

2012 ◽  
Vol 424-425 ◽  
pp. 1301-1304
Author(s):  
Hong Bo Lu ◽  
Ze Hui Wang ◽  
Yu Xin Ma
Keyword(s):  
Kinetic Analysis ◽  
Heating Rate ◽  
Biomass Burning ◽  
Combustion Process ◽  
Reaction Model ◽  
Experimental Results ◽  
Parallel Reaction ◽  
Heating Rates ◽  
Two Component ◽  
Good Agreement

Combustion of sawdust was studied using Pyris-1TGA thermogravimetric apparatus in the heating rates of 20, 40, 60K/min. The combustion process of sawdust includes three steps: losing water, precipitation and combustion of volatile, and carburization. A bicomponent parallel reaction model is created and used to simulate the combustion process of sawdust under the heating rate of 40K/min. Comparison of simulation and experimental results shows that the fitting curves are in good agreement with the experimental results

scholarly journals Non-isothermal reaction mechanism and kinetic analysis for the synthesis of monoclinic lithium zirconate (m-Li2ZrO3) during solid-state reaction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Juan P. Yasnó ◽  
Susana Conconi ◽  
Arnaldo Visintin ◽  
Gustavo Suárez
Keyword(s):  
Reaction Mechanism ◽  
Solid State ◽  
Kinetic Analysis ◽  
Solid State Reaction ◽  
Diffusion Mechanism ◽  
Model Fitting ◽  
Isoconversional Methods ◽  
Heating Rates ◽  
Isothermal Reaction ◽  
Lithium Zirconate

AbstractNon-isothermal reaction mechanism and kinetic analysis for the synthesis of monoclinic lithium zirconate (m-Li2ZrO3) were investigated by processing of TG-DTA, along with XRD, DLS, and HRTEM. For this purpose, the solid-state reaction of Li2CO3 with ZrO2 was carried out by TG-DTA at different heating rates (10, 20, and 30 °C/min) from room temperature to 1100 °C. The thermal data was used to calculate the kinetic parameters by two types of isoconversional methods: Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS). The reaction mechanism was determined by the model-fitting method, applying the Coats-Redfern (CR) approximation to the different solid-state reaction models. The results confirmed the formation of pure m-Li2ZrO3, consists of semispherical particles of about 490 nm, using a very short reaction time. The average activation energy obtained by FWO and KAS methods were 274.73 and 272.50 kJ/mol, respectively. It was found that the formation of m-Li2ZrO3 from Li2CO3 with ZrO2 is governed by the three-dimensional diffusion mechanism. Based on these results, a microscopic reaction model of the formation of m-Li2ZrO3 was proposed.

scholarly journals Pyrolysis Characteristics and Kinetic Analysis of Sediment from the Dianchi Lake in China

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Zhenfen Wu ◽  
Huilong Luo
Keyword(s):  
Kinetic Analysis ◽  
Lake Sediment ◽  
Reaction Model ◽  
Dianchi Lake ◽  
Heating Rates ◽  
Gaseous Products ◽  
Pyrolysis Characteristics ◽  
Order Chemical Reaction ◽  
Evolution Characteristics ◽  
Tg And Dtg

Pyrolysis properties and kinetic analysis of lake sediment, as well as evolution characteristics of the gaseous products at 5°C/min, 10°C/min, and 20°C/min, were investigated by TG-FTIR. Comparison to the TG and DTG curves at different heating rates, the pyrolysis process at 10°C/min could describe the sediment pyrolysis characteristics better than at 5°C/min and 20°C/min; thus the process of sediment pyrolysis could be considered as four stages. From the kinetics analysis, the nth-order chemical reaction model was suitable to describe the sediment pyrolysis reaction well. The values of n were within 2.55–3.42 and activation energy E was ranged from 15.83 KJ/mol to 57.92 KJ/mol at different heating rates. The gaseous products of H2O, CO2, CO, CH4, and SO2 and several functional groups (C-H, C=O, and C-O) could be found from the IR spectrum. From the evolution characteristics with the temperature, there were two evolution peaks for CO2 and one peak for CH4 and SO2. However, the evolution of CO always increased. Besides, the evolution peak for CO2, CH4, and SO2 all shifted to the low temperature region with the decrease of heating rate. The results could provide theoretical basis for harmless treatment and resource utilization of lake sediment.

Global Reaction Model to Describe the Kinetics of Catalytic Pyrolysis of Coffee Grounds Waste

2017 ◽  
Vol 899 ◽  
pp. 173-178 ◽  
Author(s):  
Ronydes Batista Jr. ◽  
Bruna Sene Alves Araújo ◽  
Pedro Ivo Brandão e Melo Franco ◽  
Beatriz Cristina Silvério ◽  
Sandra Cristina Danta ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Large Scale ◽  
Catalytic Pyrolysis ◽  
Petroleum Products ◽  
Reaction Model ◽  
Heating Rates ◽  
Coffee Grounds ◽  
One Step ◽  
Global Reaction ◽  
The One

In view of the constant search for new sources of renewable energy, the particulate agro-industrial waste reuse emerges as an advantageous alternative. However, despite the advantages of using the biomass as an energy source, there is still strong resistance as the large-scale replacement of petroleum products due to the lack of scientifically proven efficient conversion technologies. In this context, the pyrolysis is presented as one of the most widely used thermal decomposition processes. The knowledge of aspects of chemical kinetics, thermodynamics these will, heat and mass transfer, are so important, since influence the quality of the product. This paper presents a kinetic study of slow pyrolysis of coffee grounds waste from dynamic thermogravimetric experiments (TG), using different powder catalysts. The primary thermal decomposition was described by the one-step reaction model, which considers a single global reaction. The kinetic parameters were estimated using nonlinear regression and the differential evolution method. The coffee ground waste was dried at 105°C for 24 hours. The sample in nature was analyzed at different heating rates, being 10, 15, 20, 30 and 50 K/min. In the catalytic pyrolysis, about 5% (w/w) of catalyst were added to the sample, at a heating rate of 30 K/min. The results show that the one-step model does not accurately represent the data of weight loss (TG) and its derivative (DTG), but can do an estimative of the activation energy reaction, and can show the differences caused by the catalysts. Although no one can say anything about the products formed with the addition of the catalyst, it would be necessary to micro-pyrolysis analysis, we can say the influence of the catalyst in the samples, based on the data obtained in thermogravimetric tests.

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