scholarly journals Kinetic modelling of scrap tyre pyrolysis and oxidative desulphurisation of tyre-derived oil

2018 ◽  
Author(s):  
◽  
Peter Tumwet Cherop
Keyword(s):  
Solvent Extraction ◽  
Reaction Model ◽  
Coefficient Of Determination ◽  
Butadiene Rubber ◽  
Heating Rates ◽  
Exponential Factor ◽  
Thermogravimetric Data ◽  
Waste Tyres ◽  
Kinetics Of ◽  
Sulphur Removal

The amount of tyres generated around the world has been on the rise. This has prompted the need to explore ways in which waste tyres can be disposed. One of the ways of recycling waste tyres is through pyrolysis, a process that has the potential to produce oil products with high calorific value. However, the oil produced from waste tyre pyrolysis has a high sulphur content, resulting in high levels of toxic emissions during combustion. This research study focuses on two aspects associated with waste tyre pyrolysis. The first aspect deals with the establishment of the kinetics of scrap tyre pyrolysis while the second aspect involves the oxidative desulphurisation (ODS) of tyre-derived oil (TDO). The ODS was carried out with incorporation of the central composite design (CCD) technique of the response surface methodology (RSM) in order to model the desulphurisation process. In order to study the kinetics of the scrap tyre pyrolysis, three different models were applied to thermogravimetric data. The thermogravimetric (TG) experiments were carried out in a nitrogen environment and a temperature range of 20°C to 600°C at heating rates of 2, 5, 10, and 20 °C min-1. The models used to determine the activation energy (Ea) were Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO) and Friedman (FR) whereas the Coats-Redfern (CR) model aided in the determination of the pre-exponential factor. The FWO model had the highest average value (R2 = 0.9847) of the coefficient of determination, and therefore the Ea values from this model were loaded into the CR model to determine the pre-exponential factors and the order of the reaction model. The thermal decomposition started at a mean temperature of about 285°C and was complete at about 482 °C for the four heating rates. Results indicate that the mass losses become greater with increasing heating rates. The thermogravimetric analysis results revealed that tyre pyrolysis involves three stages i.e. removal of lubricants and oil in the scrap tyre, breakdown of natural rubber and breakdown of butadiene rubber and styrene-butadiene rubber. The average activation energies obtained were 206.01 kJ mol-1, 206.08 kJ mol-1 and 204.82 kJ mol-1 using KAS, FWO and FR models respectively. A mean pre-exponential factor of 1.27E+10 min-1 was obtained. In addition, the results showed that the pyrolysis of the tyre crumb conforms to the second order reaction model (F2). The second objective of the study involved the use of the CCD methodology to investigate the interaction of parameters during the ODS of tyre-derived oil. The oxidative desulphurisation involved the investigation of the interaction of formic acid and hydrogen peroxide amounts, reaction time and temperature. The liquid-liquid extraction was carried out using two different solvents. In addition, for one of the solvents (acetonitrile), two solvent to oil ratios were used, bringing the total number of solvent extraction scenarios to three. The three extraction scenarios were acetonitrile to oil ratio of 1:1, acetonitrile to oil ratio of 1:2 and dimethylformamide to oil ratio of 1:1. The ODS for each of the solvent extraction scenarios consisted of 21 experiments. Therefore, the total number of experiments for the three solvent extraction scenarios was 84 i.e. 21 runs for the oxidation stage and 63 runs for the solvent extraction. The maximum sulphur removal achieved was 86.05, 52.77 and 35.00 % respectively for oxidised oils extracted using 1:1 acetonitrile to oil ratio, 1:2 acetonitrile to oil ratio and 1:1 dimethylformamide to oil ratio while the corresponding minimum sulphur removal values were 34.02, 27.91 and 3.8 %. The results of the sulphur removal in which extraction was carried out at 1:1 acetonitrile to oil ratio were further analysed and modelled. From the analysis of variance (ANOVA), the reduced cubic model was found to be the best predictor of sulphur removal during the ODS process. Coefficient of determination (R2 = 0.9776), adjusted R2 = 0.9254, predicted R2 = 0.8356 all showed that the model was significant. Moreover, the p-value for the lack of fit was 0.8926, which is indication of its insignificance relative to pure error. In summary, the data obtained from the kinetic study of the scrap tyre pyrolysis could play an important role in the design and optimisation of industrial scale scrap tyre pyrolysis units. The findings could provide an insight for improvement of the general operability of scrap tyre thermal conversion processes via pyrolysis. Further research should be carried out to obtain thermogravimetric data at higher heating rates, which can then be used to model the process via the non-isothermal means. On the other hand, the findings from the oxidative desulphurisation of tyre-derived oil obtained from this research can play a key role in minimising the levels of emission during the combustion of oils obtained from the pyrolysis of waste tyres. In addition, the knowledge from the present study could be useful in commercialisation of efficient sulphur removal technology in tyre-derived oils, which can then be blended with other fuels such as diesel for use in real combustion processes. Further work with incorporation of a different organic acid, such as acetic acid and hydrogen peroxide as part of the oxidation system may be carried out to investigate the change in the extent of sulphur removal.

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.

Pyrolysis kinetics of recycled polyesters

2015 ◽  
Vol 27 (4) ◽  
pp. 523-531 ◽  
Author(s):  
Jaber Al-Juaidiyah
Keyword(s):  
Textile Industry ◽  
Degradation Kinetics ◽  
Nitrogen Atmosphere ◽  
Coefficient Of Determination ◽  
Pyrolysis Kinetics ◽  
Polybutylene Terephthalate ◽  
Exponential Factor ◽  
Content Type ◽  
Kissinger Model ◽  
Kinetics Of

Purpose – The purpose of this paper is to study the non-isothermal degradation kinetics of recycled polybutylene terephthalate, polytrimethylene terephthalate and polyethylene terephthalate using thermogravimetric analysis (TGA) in a nitrogen atmosphere. Design/methodology/approach – To achieve this goal, the author utilized standard kinetic models, such as Coats-Redfern and Kissinger equations, for analysis of the TGA data. Findings – When applied to the TGA data, the Kissinger model resulted in a coefficient of determination (R2) value greater than 0.99. Originality/value – This study describes the maiden application of the Kissinger model to obtain the pre-exponential factor (A) and activation energy (E) for different polyester systems used in the textile industry.

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.

Pyrolysis of Sugarcane Bagasse: A Consecutive Reactions Kinetic Model from TGA Experiments

2010 ◽  
Vol 660-661 ◽  
pp. 593-598 ◽  
Author(s):  
Kássia Graciele dos Santos ◽  
Taisa S. Lira ◽  
Valéria V. Murata ◽  
Marco Gianesella ◽  
Marcos A.S. Barrozo
Keyword(s):  
Kinetic Model ◽  
Sugarcane Bagasse ◽  
Room Temperature ◽  
Linear Method ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Consecutive Reactions ◽  
Kinetics Of ◽  
Good Agreement

The pyrolysis kinetics of sugarcane bagasse in nitrogen flow was studied by thermogravimetric analysis from room temperature to 1173 K at different heating rates (1.5, 3, 5, 10, 15, 20, 30 and 50 K/min). As there are three distinct devolatilization peaks in the DTG curve, each peak was associated to thermal decomposition of an individual biomass subcomponent (hemicellulose, cellulose and lignin). The kinetic model adopted was a consecutive reactions model. The kinetic parameters of the pyrolysis process, such as activation energy and pre-exponential factor, were calculated by least squares non-linear method and Scilab are used as the simulation tool. The simulated results showed a good agreement with the experimental data and the parameters found are similar to reported by the literature.

Kinetic Studies on the Thermal Synthesis of Fluorapatite: Model Free and Model-Fitting Methods

2018 ◽  
Vol 28 ◽  
pp. 75-89
Author(s):  
Hamid Reza Javadinejad ◽  
Sayed Ahmad Hosseini ◽  
Mohsen Saboktakin Rizi ◽  
Eiman Aghababaei ◽  
Hossein Naseri
Keyword(s):  
Activation Energy ◽  
Model Fitting ◽  
Kinetic Studies ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Heating Rates ◽  
Thermal Synthesis ◽  
Exponential Factor ◽  
Model Free ◽  
Master Plots

The kinetic study for the synthesis of Fluorapatite has been done using the thermogravimetric technique under non-isothermal conditions and at four heating rates of 5, 10, 15 and 20 °C. Both model free and model-fitting methods were used to investigate kinetic parameters. Calcium oxide, phosphorus pentoxide and calcium fluoride were used as the precursor materials. The activation energy values were calculated through model-fitting and isoconversional methods and were used to predict the reaction model and pre-exponential factor. In this case several techniques were considered such as master plots and compensation effects. The results indicated that the reaction mechanism was chemically controlled with second and third order reaction models in the whole range of conversion which the activation energy varied from 25 to 43 kJ/mol.

Kinetic Study of Waste Wood and Its Carbonization

2002 ◽  
Author(s):  
Hoque Md. Mozammel ◽  
Masahiro Ota
Keyword(s):  
Kinetic Parameters ◽  
Thermal Analyses ◽  
Least Square ◽  
Thermochemical Conversion ◽  
Heating Rates ◽  
Waste Wood ◽  
Exponential Factor ◽  
Thermogravimetric Data ◽  
Ignition Characteristics ◽  
Dta Curves

This study deals with the conversion of waste wood into solid fuel charcoal. Thermogravimetric and differential thermal analyses techniques are used to investigate the kinetics of thermochemical conversion of waste wood. The thermal degradation characteristics and the kinetic parameters (order of reaction, activation energy and pre-exponential factor) are determined at different heating rates using TG/DTA curves. The decomposition of the components could be modeled by an Arrhenius kinetic expression. The kinetic parameters are determined from the thermogravimetric data by a least square technique. The order of reaction and activation of energy vary from 0.41 to 0.52 and 10.86 to 15.10 kJ/mole respectively. Finally attempts are taken to produce charcoal from the waste wood and the charcoals are characterized in respect of yield, electrical conductivity, ESCA (electron spectroscopy for chemical analysis), XRD (x-ray diffraction) and ignition characteristics.

scholarly journals Pyrolysis of waste tyres – The effect of reaction kinetics on the results of thermogravimetric analysis

2017 ◽  
Vol 38 (3) ◽  
pp. 363-377 ◽  
Author(s):  
Robert Cherbański ◽  
Krzysztof Wróblewski ◽  
Eugeniusz Molga
Keyword(s):  
Kinetic Parameters ◽  
Scale Up ◽  
Internal Heat ◽  
Heating Rates ◽  
Transfer Resistance ◽  
First Derivative ◽  
Experimental Part ◽  
Waste Tyres ◽  
Kinetics Of ◽  
Internal Heat Transfer

Abstract This paper presents a systematic thermogravimetric (TG) study on the kinetics of end-of-life tyre (ELT) pyrolysis. In the experimental part of this work, TG results are compared for tyre samples of different mass and size. This shows that the conduction resistance in the milligram scale (up to ~100 mg) tyre sample can be neglected. A comparison of experimental results demonstrates that the characteristic maxima on the DTG curve (the first derivative of TG signal) shift towards higher temperatures for higher heating rates. This phenomenon is explained to have kinetic origin and it is not caused by the internal heat transfer resistance. In the modelling part of this work, the kinetic parameters of the Three-Component Simulation Model (TCSM) are calculated and compared to the literature values. Testing of the kinetic model is carried out using experiments with a varying heating rate. This shows the limitation of the simplified kinetic approach and the appropriate selection method of the kinetic parameters.

scholarly journals Comparison of the dehydration kinetics of solid state compounds of 2-methoxybenzylidenepyruvate with some divalent metal ions

2010 ◽  
Vol 35 (1) ◽  
pp. 7-18
Author(s):  
M. Kobelnik ◽  
C. A. Ribeiro ◽  
D. S. Dias ◽  
G. A. Bernabé ◽  
M. S. Crespi
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Nitrogen Atmosphere ◽  
Divalent Metal ◽  
Point Of View ◽  
Conversion Degree ◽  
Divalent Metal Ions ◽  
Heating Rates ◽  
Exponential Factor ◽  
Kinetics Of

Divalent metal complexes of ligand 2-methoxybenzylidenepyruvate with Fe, Co, Ni, Cu and Zn as well as sodium salt were synthesized and investigated in the solid state. TG curves of these compounds were obtained with masses sample of 1 and 5mg under nitrogen atmosphere. Different heating rates were used to characterize and study these compounds from the kinetic point of view. The activation energy and pre-exponential factor were obtained applying the Wall-Flynn-Ozawa method to the TG curves. The obtained data were evaluated and the values of activation energy (Ea / kJ mol-1) was plotted in function of the conversion degree (α). The results show that due to mass sample, different activation energies were obtained. The results are discussed mainly taking into account the linear dependence between the activation energy and the pre exponential factor, where was verified the effect of kinetic compensation (KCE) and possible linear relations between the dehydrations steps of these compounds.

Thermogravimetric Analysis and Pyrolysis Kinetics of Tannery Wastes in an Inert Atmosphere

2020 ◽  
Vol 115 (4) ◽  
pp. 123-131
Author(s):  
Lan Luo ◽  
Cheng-Kung Liiu ◽  
Eleanor Brown ◽  
Fang Wang ◽  
Yadi Hu ◽  
...  
Keyword(s):  
Reaction Model ◽  
Inert Atmosphere ◽  
Single Step ◽  
Industrial Wastes ◽  
Future Application ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Renewable Chemicals ◽  
Tannery Wastes ◽  
Kinetics Of

Industrial wastes generated from tanneries contain large quantities of water-insoluble proteins, which may be used for the production of composite materials, renewable chemicals and energy. In this work, the pyrolysis kinetics of powdered sheep fur wastes (SFW) was studied by thermogravimetry (TG) at different heating rates from room temperature to 600°C in nitrogen atmosphere. TG results revealed that there are three stages in this process. The overall apparent activation energy (E) in the main pyrolysis stage was determined to be 275.6 kJ mol-1 by modified Kissinger-Akahira-Sunose (MKAS) method. Because the pyrolysis of SFW could not be described by a single-step reaction, the experimental DTG curve of SFW was deconvoluted into three individual peaks followed by reconstruction of TG curves corresponding to three pseudo components. The average values of E obtained for these pseudo components are 234.7 kJ mol-1, 176.4 kJ mol-1, and 186.2 kJ mol-1, respectively. Generalized master-plots method indicated that the SFW pyrolysis may follow the random nucleation and growth mechanism (Avrami-Erofeev model). Reaction model functions f(?) for these pseudo components could be expressed as: f(?)=3.1(1-?)[-ln(1-?)]0.67; f(?)=3.6(1-?)[-ln(1-?)]0.72, and  f(?)=3.9(1-?)[-ln(1-?)]0.74, respectively. These results may provide insight for further studies as well as for future application of pyrolysis technology for tannery wastes. 

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