scholarly journals Thermal decomposition of potassium titanium oxalate

2011 ◽  
Vol 76 (7) ◽  
pp. 1015-1026 ◽  
Author(s):  
Karuvanthodi Muraleedharan ◽  
Labeeb Pasha
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Model Fitting ◽  
Nitrogen Atmosphere ◽  
Single Step ◽  
Heating Rates ◽  
Decomposition Stage ◽  
Model Free ◽  
Good Agreement

The thermal decomposition of potassium titanium oxalate (PTO) was studied using non-isothermal thermogravimetry at different heating rates under a nitrogen atmosphere. The thermal decomposition of PTO proceeds mainly through five stages forming potassium titanate. The theoretical and experimental mass loss data are in good agreement for all stages of the thermal decomposition of PTO. The third thermal decomposition stage of PTO, the combined elimination of carbon monoxide and carbon dioxide, were subjected to kinetic analyses both by the method of model fitting and by the model free approach, which is based on the isoconversional principle. The model free analyses showed that the combined elimination of carbon monoxide and carbon dioxide and formation of final titanate in the thermal decomposition of PTO proceeds through a single step with an activation energy value of about 315 kJ mol-1.

scholarly journals Synthesis, characterization and thermal decomposition of ethyl-2’-amino-5’-cyano-6’-(1H-indole-3yl)-2-oxospiro[indoline-3,4’-pyran]-3’-carboxylate under non‐isothermal condition in nitrogen atmosphere

2019 ◽  
Vol 10 (1) ◽  
pp. 72-81
Author(s):  
Ganesan Nalini ◽  
Natesan Jayachandramani ◽  
Radhakrishnan Suresh ◽  
Prakasam Thirumurugan ◽  
Venugopal Thanikachalam ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Model Fitting ◽  
Isothermal Condition ◽  
Nitrogen Atmosphere ◽  
Single Step ◽  
Heating Rates ◽  
Model Free ◽  
Ft Ir ◽  
Step Mechanism

A new compound, spiro-oxindole derivative compound namely ethyl-2ʹ-amino-5ʹ-cyano-6ʹ-(1H-indole-3yl)-2-oxospiro[indoline-3,4ʹ-pyran]-3ʹ-carboxylate (EACIOIPC) has been synthesized and characterized by microanalysis, FT-IR, mass spectrum and NMR (1H and 13C) techniques. The thermal decomposition of the compound was studied by thermogravimetric analysis under dynamic nitrogen atmosphere at different heating rates of 10, 15, 20 and 30 K/min. The kinetic parameters were calculated using model-free (Friedman’s, Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods) and model-fitting (Coats and Redfern (CR)) methods. The decomposition process of EACIOIPC followed a single step mechanism as evidenced from the data. Existence of compensation effect is noticed for the decomposition of EACIOIPC. Invariant kinetic parameters are consistent with the average values obtained by Friedman and KAS in conversional methods.

scholarly journals Determination of Kinetic Parameters for the Thermal Decomposition of Parthenium hysterophorus

2018 ◽  
Vol 22 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Suraj B. Singh ◽  
Muammel M. Hanon ◽  
Rekha Rawat
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Model Fitting ◽  
Frequency Factor ◽  
Heating Rates ◽  
Model Free ◽  
Higher Temperature ◽  
Good Agreement ◽  
Maximum Weight Loss

Abstract A kinetic study of pyrolysis process of Parthenium hysterophorous is carried out by using thermogravimetric analysis (TGA) equipment. The present study investigates the thermal degradation and determination of the kinetic parameters such as activation E and the frequency factor A using model-free methods given by Flynn Wall and Ozawa (FWO), Kissinger-Akahira-Sonuse (KAS) and Kissinger, and model-fitting (Coats Redfern). The results derived from thermal decomposition process demarcate decomposition of Parthenium hysterophorous among the three main stages, such as dehydration, active and passive pyrolysis. It is shown through DTG thermograms that the increase in the heating rate caused temperature peaks at maximum weight loss rate to shift towards higher temperature regime. The results are compared with Coats Redfern (Integral method) and experimental results have shown that values of kinetic parameters obtained from model-free methods are in good agreement. Whereas the results obtained through Coats Redfern model at different heating rates are not promising, however, the diffusion models provided the good fitting with the experimental data.

Thermogravimetric Analysis and Kinetic Study on Catalytic Pyrolysis of Rice Husk Pellet using Its Ash as a Low-cost In-situ Catalyst

2021 ◽  
Vol 11 (1) ◽  
pp. 207-219
Author(s):  
Wusana Agung Wibowo ◽  
Rochim Bakti Cahyono ◽  
Rochmadi Rochmadi ◽  
Arief Budiman
Keyword(s):  
Thermogravimetric Analysis ◽  
Rice Husk ◽  
Catalytic Effect ◽  
Low Cost ◽  
Weight Ratio ◽  
Nitrogen Atmosphere ◽  
Energy Of Activation ◽  
Heating Rates ◽  
Decomposition Stage ◽  
Model Free

The thermogravimetric behaviors and the kinetic parameters of uncatalyzed and catalyzed pyrolysis processes of a mixture of powdered raw rice husk (RRH) and its ash (RHA) in the form of pellets were determined by thermogravimetric analysis at three different heating rates, i.e., 5, 10, and 20 K/min, from 303 to 873 K. This research aimed to prove that the rice husk ash has a catalytic effect on rice husk pyrolysis. To investigate the catalytic effect of RHA, rice husk pellets (RHP) with the weight ratio of RRH:ARH of 10:2 were used as the sample. Model-free methods, namely Friedman (FR), Kissinger-Akahira-Sunose (KAS), and Flynn-Wall-Ozawa (FWO), were used to calculate the apparent energy of activation ( ). The thermogravimetric analysis showed that the decomposition of RHP in a nitrogen atmosphere could be divided into three stages: drying stage (303-443 K), the rapid decomposition stage (443-703 K), and the slow decomposition stage (703-873 K). The weight loss percentages of each stage for both uncatalyzed and catalyzed pyrolysis of RHP were 2.4-5.7%, 35.5-59.4%, and 2.9-12.2%, respectively. Using the FR, FWO, and KAS methods, the values of  for the degrees of conversion (a) of 0.1 to 0.65 were in the range of 168-256 kJ/mol for the uncatalyzed pyrolysis and 97-204 kJ/mol for the catalyzed one. We found that the catalyzed pyrolysis led the  to have values lower than those got by the uncatalyzed one. This phenomenon might prove that RHA has a catalytic effect on RHP pyrolysis by lowering the energy of activation.

scholarly journals Pyrolysis of Low Density Polyethylene: Kinetic Study Using TGA Data and ANN Prediction

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 891 ◽  
Author(s):  
Ibrahim Dubdub ◽  
Mohammed Al-Yaari
Keyword(s):  
Kinetic Parameters ◽  
Transfer Functions ◽  
Model Fitting ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Ann Model ◽  
Heating Rates ◽  
Highly Efficient ◽  
Model Free ◽  
Good Agreement

Pyrolysis of waste low-density polyethylene (LDPE) is considered to be a highly efficient, promising treatment method. This work aims to investigate the kinetics of LDPE pyrolysis using three model-free methods (Friedman, Flynn-Wall-Qzawa (FWO), and Kissinger-Akahira-Sunose (KAS)), two model-fitting methods (Arrhenius and Coats-Redfern), as well as to develop, for the first time, a highly efficient artificial neural network (ANN) model to predict the kinetic parameters of LDPE pyrolysis. Thermogravimetric (TG) and derivative thermogravimetric (DTG) thermograms at 5, 10, 20 and 40 K min−1 showed only a single pyrolysis zone, implying a single reaction. The values of the kinetic parameters (E and A) of LDPE pyrolysis have been calculated at different conversions by three model-free methods and the average values of the obtained activation energies are in good agreement and ranging between 193 and 195 kJ mol−1. In addition, these kinetic parameters at different heating rates have been calculated using Arrhenius and Coats-Redfern methods. Moreover, a feed-forward ANN with backpropagation model, with 10 neurons in two hidden layers and logsig-logsig transfer functions, has been employed to predict the thermogravimetric analysis (TGA) kinetic data. Results showed good agreement between the ANN-predicted and experimental data (R > 0.9999). Then, the selected network topology was tested for extra new input data with a highly efficient performance.

Non-Isothermal Decomposition Kinetic of Polypropylene/Hydrotalcite Composite

2019 ◽  
Vol 19 (11) ◽  
pp. 7493-7501 ◽  
Author(s):  
Sheng Xu ◽  
Min Zhang ◽  
Siyu Li ◽  
Moyu Yi ◽  
Shigen Shen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Nitrogen Atmosphere ◽  
Heating Rates ◽  
Decomposition Reactions ◽  
Kinetic And Thermodynamic Parameters ◽  
Málek Method ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Thermal Stability Of

P3O5-10 pillared Mg/Al hydrotalcite (HTs) as a functional fire-retarding filler was successfully prepared by impregnation-reconstruction, where the HTs was used to prepare polypropylene (PP) and HTs composite (PP/HTs). Thermal decomposition was crucial for correctly identifying the thermal behavior for the PP/HTs, and studied using thermogravimetry (TG) at different heating rates. Based on single TG curves and Málek method, as well as 41 mechanism functions, the thermal decompositions of the PP/HTs composite and PP in nitrogen atmosphere were studied under non-isothermal conditions. The mechanism functions of the thermal decomposition reactions for the PP/HTs composite and PP were separately “chemical reaction F3” and “phase boundary reaction R2,” which were also in good agreement with corresponding experimental data. It was found that the addition of the HTs increased the apparent activation energy Ea of the PP/HTs comparing to the PP, which improved the thermal stability of the polypropylene. A difference in the set of kinetic and thermodynamic parameters was also observed between the PP/HTs and PP, particularly with respect to lower ΔS≠ value assigned to higher thermal stability of the PP/HTs composite.

Thermo-catalytic decomposition of polystyrene waste: Comparative analysis using different kinetic models

2019 ◽  
Vol 38 (2) ◽  
pp. 202-212 ◽  
Author(s):  
Ghulam Ali ◽  
Jan Nisar ◽  
Munawar Iqbal ◽  
Afzal Shah ◽  
Mazhar Abbas ◽  
...  
Keyword(s):  
Activation Energy ◽  
Copper Oxide ◽  
Solid Waste ◽  
Thermodynamic Parameters ◽  
Model Fitting ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Inert Atmosphere ◽  
Heating Rates ◽  
Model Free

Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin−1, 10°Cmin−1, 15°Cmin−1 and 20°Cmin−1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats–Redfern) and model free methods (Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats–Redfern, Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman models were found in the ranges 105–148.48 kJmol−1, 99.41–140.52 kJmol−1, 103.67–149.15 kJmol−1 and 99.93–141.25 kJmol−1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.

scholarly journals Kinetic Analysis of the Thermal Decomposition of Polymer-Bonded Explosive Based on PETN: Model-Fitting Method and Isoconversional Method

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Trung Toan Nguyen ◽  
Duc Nhan Phan ◽  
Van Thom Do ◽  
Hoang Nam Nguyen
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Model Fitting ◽  
Isoconversional Method ◽  
Isothermal Tg ◽  
Decomposition Reactions ◽  
Model Free ◽  
Negative Effect ◽  
Adverse Influence ◽  
Vacuum Stability Test

This work investigates kinetics and thermal decomposition behaviors of pentaerythritol tetranitrate (PETN) and two polymer-bonded explosive (PBX) samples created from PETN (named as PBX-PN-85 and PBX-PP-85) using the vacuum stability test (VST) and thermogravimetry (TG/DTG) techniques. Both model-free (isoconversional) and model-fitting methods were applied to determine the kinetic parameters of the thermal decomposition. It was found that kinetic parameters obtained by the modified Kissinger–Akahira–Sunose method (using non-isothermal TG/DTG data) were close to those obtained by the isoconversional and model-fitting methods that use isothermal VST data. The activation energy values of thermal decomposition reactions were 125.6–137.1, 137.3–144.9, and 143.9–152.4 kJ·mol−1 for PBX-PN-85, PETN, and PBX-PP-85, respectively. The results demonstrate the negative effect of the nitrocellulose-based binder in reducing the thermal stability of single PETN, while the polystyrene-based binder seemingly shows no adverse influence on the thermal decomposition of PETN in our presented PBX compositions.

scholarly journals Pyrolysis Kinetic Properties of Thermal Insulation Waste Extruded Polystyrene by Multiple Thermal Analysis Methods

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5595
Author(s):  
Ang Li ◽  
Wenlong Zhang ◽  
Juan Zhang ◽  
Yanming Ding ◽  
Ru Zhou
Keyword(s):  
Reaction Mechanism ◽  
Thermal Insulation ◽  
Conversion Rate ◽  
Model Fitting ◽  
Pso Algorithm ◽  
Energy Utilization ◽  
Kinetic Properties ◽  
Insulation Material ◽  
Heating Rates ◽  
Model Free

Extruded polystyrene (XPS) is a thermal insulation material extensively applied in building systems. It has attracted much attention because of outstanding thermal insulation performance, obvious flammability shortcoming and potential energy utilization. To establish the reaction mechanism of XPS’s pyrolysis, thermogravimetric experiments were performed at different heating rates in nitrogen, and multiple methods were employed to analyze the major kinetics of pyrolysis. More accurate kinetic parameters of XPS were estimated by four common model-free methods. Then, three model-fitting methods (including the Coats-Redfern, the iterative procedure and masterplots method) were used to establish the kinetic model. Since the kinetic models established by the above three model-fitting methods were not completely consistent based on different approximations, considering the effect of different approximates on the model, the reaction mechanism was further established by comparing the conversion rate based on the model-fitting methods corresponding to the possible reaction mechanisms. Finally, the accuracy of the above model-fitting methods and Particle Swarm Optimization (PSO) algorithm were compared. Results showed that the reaction function g(α) = (1 − α)−1 − 1 might be the most suitable to characterize the pyrolysis of XPS. The conversion rate calculated by masterplots and PSO methods could provide the best agreement with the experimental data.

scholarly journals Kinetic studies on the pyrolysis of plastic waste using a combination of model-fitting and model-free methods

2020 ◽  
Vol 38 (1_suppl) ◽  
pp. 77-85 ◽  
Author(s):  
Zhitong Yao ◽  
Shaoqi Yu ◽  
Weiping Su ◽  
Weihong Wu ◽  
Junhong Tang ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Thermogravimetric Analysis ◽  
Compensation Effect ◽  
Model Fitting ◽  
Plastic Waste ◽  
Plastic Shell ◽  
Ozawa Method ◽  
Heating Rates ◽  
Helium Atmosphere ◽  
Model Free

In this work, the pyrolysis behavior of plastic waste—TV plastic shell—was investigated, based on thermogravimetric analysis and using a combination of model-fitting and model-free methods. The possible reaction mechanism and kinetic compensation effects were also examined. Thermogravimetric analysis indicated that the decomposition of plastic waste in a helium atmosphere can be divided into three stages: the minor loss stage (20–300°C), the major loss stage (300–500°C) and the stable loss stage (500–1000°C). The corresponding weight loss at three different heating rates of 15, 25 and 35 K/min were determined to be 2.80–3.02%, 94.45–95.11% and 0.04–0.16%, respectively. The activation energy ( Ea) and correlation coefficient ( R2) profiles revealed that the kinetic parameters calculated using the Friedman and Kissinger–Akahira–Sunose method displayed a similar trend. The values from the Flynn–Wall–Ozawa and Starink methods were comparable, although the former gave higher R2 values. The Eα values gradually decreased from 269.75 kJ/mol to 184.18 kJ/mol as the degree of conversion ( α) increased from 0.1 to 0.8. Beyond this range, the Eα slightly increased to 211.31 kJ/mol. The model-fitting method of Coats–Redfern was used to predict the possible reaction mechanism, for which the first-order model resulted in higher R2 values than and comparable Eα values to those obtained from the Flynn–Wall–Ozawa method. The pre-exponential factors (ln A) were calculated based on the F1 reaction model and the Flynn–Wall–Ozawa method, and fell in the range 59.34–48.05. The study of the kinetic compensation effect confirmed that a compensation effect existed between Ea and ln A during the plastic waste pyrolysis.

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