scholarly journals Comparison of CO2 gasification of coal in isothermal and non-isothermal conditions

2019 ◽  
Vol 108 ◽  
pp. 02017
Author(s):  
Grzegorz Czerski ◽  
Przemysław Grzywacz ◽  
Katarzyna Śpiewak
Keyword(s):  
Kinetic Parameters ◽  
Bituminous Coal ◽  
Conversion Degree ◽  
Heating Rates ◽  
Exponential Factor ◽  
Isothermal Method ◽  
Isothermal Conditions ◽  
Thermogravimetric Analyzer ◽  
Gasification Process ◽  
Gasification Reaction

The thermogravimetric method allows to carry out measurements both in isothermal conditions for a given temperature and in non-isothermal conditions at a set heating rate. The aim of the work was to compare the process of gasification of the same coal in an atmosphere of CO2 under isothermal and non-isothermal conditions. The measurements were carried out with the use of DynTHERM Thermogravimetric analyzer by Rubotherm. Char derived from Polish bituminous coal “Janina” was used as material for gasification. In case of the isothermal method the measurements were performed at three temperatures – 850 °C, 900 °C and 950 °C, while in case of the non-isothermal method for three heating rates, i.e. 3 K/min, 5 K/min and 10 K/min. Based on the results obtained, kinetics curves of conversion degree of the gasification process were developed and kinetic parameters of the gasification reaction i.e. reaction order, activation energy and pre-exponential factor were determined. The values of the kinetic parameters obtained from measurements performed in isothermal and non-isothermal conditions were compared.

scholarly journals Effect of Pyrolysis Atmosphere on the Gasification of Waste Tire Char

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 34
Author(s):  
Przemysław Grzywacz ◽  
Grzegorz Czerski ◽  
Wojciech Gańczarczyk
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Inert Atmosphere ◽  
Argon Atmosphere ◽  
Conversion Degree ◽  
Heating Rates ◽  
Mean Values ◽  
Co2 Gasification ◽  
Gasification Process ◽  
Lower Reactivity

The aim of the study is to assess the influence of the atmosphere during pyrolysis on the course of CO2 gasification of a tire waste char. Two approaches were used: the pyrolysis step was carried out in an inert atmosphere of argon (I) or in an atmosphere of carbon dioxide (II). The examinations were carried out in non-isothermal conditions using a Rubotherm DynTherm thermobalance in the temperature range of 20–1100 °C and three heating rates: 5, 10 and 15 K/min. Based on the results of the gasification examinations, the TG (Thermogravimetry) and DTG (Derivative Thermogravimetry) curves were developed and the kinetic parameters were calculated using the KAS (Kissinger-Akahira-Sunose) and FWO (Flynn-Wall-Ozawa) methods. Additionally, the CO2 gasification of tire chars reaction order (n), was evaluated, and the kinetic parameters were calculated with the use of Coats and Redfern method. Tire waste char obtained in an argon atmosphere was characterized by lower reactivity, which was reflected in shift of conversion and DTG curves to higher temperatures and higher mean values of activation energy. A variability of activation energy values with the progress of the reaction was observed. For char obtained in an argon atmosphere, the activation energy varied in the range of 191.1–277.2 kJ/mol and, for a char obtained in an atmosphere of CO2, in the range of 148.0–284.8 kJ/mol. The highest activation energy values were observed at the beginning of the gasification process and the lowest for the conversion degree 0.5–0.7.

scholarly journals Curing Kinetic Parameters of Epoxy Composite Reinforced with Mallow Fibers

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3939 ◽  
Author(s):  
Lucio Fabio Cassiano Nascimento ◽  
Fernanda Santos da Luz ◽  
Ulisses Oliveira Costa ◽  
Fábio de Oliveira Braga ◽  
Édio Pereira Lima Júnior ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Industrial Process ◽  
Diglycidyl Ether ◽  
Response Surfaces ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Exponential Factor ◽  
Curing Kinetic ◽  
Technological Tool

Knowledge about the curing behavior of a thermosetting resin and its composites includes the determination of kinetic parameters and constitutes an important scientific and technological tool for industrial process optimization. In the present work, the differential scanning calorimetry (DSC) technique was used to determine several curing parameters for pure epoxy and its composite reinforced with 20 vol % mallow fibers. Analyses were performed with heating rates of 5, 7.5, and 10 °C/min, as per the ASTM E698 standard. The kinetic related parameters, that is, activation energy (E), Avrami’s pre-exponential factor (Z), and mean time to reach 50% cure (t½), were obtained for the materials, at temperatures ranging from 25 to 100 °C. Response surfaces based on the mathematical relationship between reaction time, transformed fraction, and temperature were provided for optimization purposes. The results showed that the average curing time used for the production of diglycidyl ether of bisphenol A/triethylenetetramine (DGEBA/TETA) epoxy systems or their composites reinforced with natural mallow fibers can be considerably reduced as the temperature is increased up to a certain limit.

scholarly journals Gasification Kinetics of Bituminous Coal Char in the Mixture of CO2, H2O, CO, and H2

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 496 ◽  
Author(s):  
Junwei Chen ◽  
Weibin Chen ◽  
Yang Jiao ◽  
Xidong Wang
Keyword(s):  
Bituminous Coal ◽  
Gas Diffusion ◽  
Coal Char ◽  
Conversion Degree ◽  
Diffusion Control ◽  
Diffusion Resistance ◽  
Gasification Process ◽  
Control Step ◽  
Kinetics Of ◽  
Gasification Temperature

The gasification kinetics of bituminous coal char was investigated in a mixture of CO2, H2O, CO, H2, and N2 under isothermal conditions. In addition, the impacts of gasification temperature, gasification time, and gas composition on the gasification process were analyzed. As the experimental results suggest, there is a significant increase of the carbon conversion degree of bituminous coal char not just when gasification temperature and time increase, but also when H2 and CO concentration decreases. The kinetics of bituminous coal char in the gasification process was successfully modeled as a shrinking unreacted core. It is concluded that the gasification of bituminous coal char is controlled by an internal chemical reaction in the early stage and diffusion in the later stage. The activation energies of bituminous coal char gasification for different stages were studied. Moreover, it is proposed for the first time, to our knowledge, that the diffusion-control step is significantly shortened with the decrease of the CO2/H2O ratio. As scanning-electron-microscopy results suggest, bituminous coal char gasified in CO2/H2O = 1/3 atmosphere has numerous inner pores (0–5 m). Therefore, in the process of gasification, the inner pores provide a gas channel that reduces the gas diffusion resistance and thus shortens the diffusion-control step. These results can serve as a reference for industrialized application of the technology of coal gasification direct reduced iron.

Kinetic Analysis on Catalytic Co-Gasification of Rubber Seed Shell and High Density Polyethylene Mixtures

2014 ◽  
Vol 625 ◽  
pp. 251-254
Author(s):  
Bridgid Chin Lai Fui ◽  
Suzana Yusup ◽  
Ahmed Al Shoaibi ◽  
Pravin Kannan ◽  
Chandrasekar Srinivasakannan ◽  
...  
Keyword(s):  
High Density Polyethylene ◽  
Weight Ratio ◽  
High Density ◽  
Heating Rates ◽  
Exponential Factor ◽  
Rubber Seed ◽  
Gasification Process ◽  
System A ◽  
One Step ◽  
Decomposition Behavior

In this paper, the catalytic co-gasification of rubber seed shell and high density polyethylene mixtures (0.2:0.8 weight ratio of HDPE:RSS) are investigated using a non-isothermal thermogravimetric analysis (TGA) system in a range of heating rates of 10, 20, 30 and 50 K/min within the temperature range of 323-1173 K. The argon gas is supplied at a flowrate of 100 ml/min and the steam is generated from superheater at 383 K. The steam is injected at flowrate of 300 μL/hour into the TGA system. A commercial nickel powder is used as the catalyst for the gasification process. The thermal decomposition behavior and synergistic effect of the HDPE/RSS mixture are investigated. The activation energy, EA and pre-exponential factor, A are determined based on one step integral method.

scholarly journals Thermogravimetric kinetic study of solid recovered fuels pyrolysis

2018 ◽  
Vol 72 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Milos Radojevic ◽  
Martina Balac ◽  
Vladimir Jovanovic ◽  
Dragoslava Stojiljkovic ◽  
Nebojsa Manic
Keyword(s):  
Thermal Analysis ◽  
Kinetic Parameters ◽  
Simultaneous Thermal Analysis ◽  
Experimental Tests ◽  
Nitrogen Atmosphere ◽  
Cement Industry ◽  
Thermochemical Conversion ◽  
Gravimetric Analysis ◽  
Heating Rates ◽  
Exponential Factor

In the Republic of Serbia there are significant quantities of coffee and tire wastes that can be utilized as Solid Recovered Fuel (SRF) and used as an additional fuel for co?combustion with coal and biomass in energy production and cement industry sectors. Differences between SRF and base fuel are a cause of numerous problems in design of burners. The objective of this study was to determine the kinetic parameters for the thermochemical conversion of selected SRF using Simultaneous Thermal Analysis (STA). Samples of coffee and tire waste were used for the experimental tests. Thermal analysis was carried out in nitrogen atmosphere at three different heating rates 10, 15 and 20 K/min for each sample, while it was heated from room temperature up to 900?C. Two sample sizes x <0.25 mm and 0.25 < x <0.5 mm of each SRF were used in experiments, in order to obtain reliable Thermal Gravimetric Analysis (TGA) data for estimation of kinetic parameters for SRF pyrolysis. Experimental results were used for determination of pre-exponential factor and activation energy according to methods presented in the literature. Presented research provides valuable data of coffee and tire waste that can be used for the burners design.

scholarly journals Kinetic analysis of the pyrolysis of apricot stone and its main components via distributed activation energy mode

BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1187-1204
Author(s):  
Huanhuan Ma ◽  
Yimeng Zhang ◽  
Liangcai Wang ◽  
Zhengxiang Zhu ◽  
Yu Chen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Energy Distribution ◽  
Apparent Activation Energy ◽  
Early Stage ◽  
Conversion Degree ◽  
Heating Rates ◽  
Continuous Increase ◽  
Thermogravimetric Analyzer ◽  
Energy Mode ◽  
Main Components

The kinetics of pyrolysis of apricot stone and its main components, i.e., lignin, cellulose, and hemicellulose, were investigated via distributed activation energy mode. Experiments were done in a thermogravimetric analyzer at heating rates of 10, 20, 30, and 40 K·min-1 under nitrogen. The activation energy distribution peaks for the apricot stone, lignin, cellulose, and hemicellulose were centered at 246, 318, 364, and 170 kJ·mol-1, respectively. The activation energy distribution for the apricot stone slightly changed; lignin exhibited the widest distribution; and cellulose exhibited the highest activation energy at a conversion degree (α) of less than 0.75. At low pyrolysis temperatures (400 K to 600 K), the pyrolysis of hemicellulose was the main pyrolysis reaction. The apparent activation energy for the apricot stone mainly depended on the pyrolysis of hemicellulose and a small amount of lignin, and the activation energy was low in the early stage of pyrolysis. With the continuous increase in the pyrolysis temperatures (600 K to 660 K), the thermal weight loss of cellulose and lignin was intense. The apparent activation energy for the apricot stone mainly resulted from the pyrolysis of cellulose and lignin, and a higher activation energy was observed in the later stage of pyrolysis.

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 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 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.

scholarly journals DETERMINATION OF KINETIC PARAMETERS OF CHEERY TREE PYROLYSIS USING KISSINGER METHOD

2020 ◽  
pp. 135
Author(s):  
Milan Protic ◽  
Ana Miltojevic ◽  
Miomir Raos ◽  
Petar Đekić
Keyword(s):  
Kinetic Parameters ◽  
Fossil Fuels ◽  
Chemical Properties ◽  
Kinetic Studies ◽  
Kissinger Method ◽  
Thermochemical Conversion ◽  
Heating Rates ◽  
Exponential Factor ◽  
Reliable Determination

In the global quest for substitution of fossil fuels, biomass is regarded as one of the most promising alternatives. Thermochemical conversion is one of the dominant biomass-to-energy processing routes with pyrolysis as one of the options that gained importance in recent years. In this paper pyrolysis experiments of cheery tree samples were performed. The objective of this research was to determine selected physical and chemical properties of cheery related to thermochemical conversion. The samples were pyrolysed in a thermogravimetric analyzer in an inert, nitrogen, atmosphere at four different heating rates 1, 2, 5 and 10 °C/min. Pyrolysis occurred, as expected, in three step: loss of moisture and light volatiles, active and passive pyrolysis. With an increase in heating rate a lateral shift of the maximum rate of weight loss for the thermal decomposition to higher temperatures was observed, as well as an increase in the amount of residual char. Moreover, kinetic studies were performed using the Kissinger method. The activation energy was calculated to be 155.26 kJ/mol, while the pre-exponential factor was 1.685×1012 min-1. Obtained results are comparable to values reported in literature. Kissinger method is straightforward and offers the possibility for fast and reliable determination of kinetic parameters.

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