scholarly journals Comparative study of the reaction kinetics of three residual biomasses

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2891-2905
Author(s):  
Arnaldo Martinez ◽  
Lourdes Meriño ◽  
Alberto Albis ◽  
Jorge Ortega
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Lignin Content ◽  
Cellulose Degradation ◽  
Calorific Value ◽  
Degradation Process ◽  
Proximate Analysis ◽  
Cellulose Content ◽  
Heating Rates ◽  
Biomass Residues

Kinetic analysis for the combustion of three agro-industrial biomass residues (coconut husk, corn husk, and rice husk) was carried out in order to provide information for the generation of energy from them. The analysis was performed using the results of the data obtained by thermogravimetric analysis (TGA) at three heating rates (10, 20, and 30 K/min). The biomass residues were characterized in terms of proximate analysis, elemental analysis, calorific value, lignin content, α-cellulose content, hemicellulose content, and holocellulose content. The biomass fuels were thermally degraded in an oxidative atmosphere. The results showed that the biomass thermal degradation process is comprised of the combustion of hemicellulose, cellulose, and lignin. The kinetic parameters of the distributed activation energy model indicated that the activation energy distribution for the pseudocomponents follows lignin, cellulose, and hemicellulose in descending order. The activation energy values for each set of reactions are similar between the heating rates, which suggests that it is independent of the heating rate between 10 K/min and 30 K/min. For all the biomass samples, the increased heating rate resulted in the overlap of the hemicellulose and cellulose degradation events.

The Effects of Temperature and Heating Rate on the Preparation of Stalk Char

2012 ◽  
Vol 496 ◽  
pp. 88-93
Author(s):  
Jian Pan ◽  
Lin Wang
Keyword(s):  
Heating Rate ◽  
Pyrolysis Temperature ◽  
Calorific Value ◽  
Product Yield ◽  
Proximate Analysis ◽  
High Yield ◽  
Heating Rates ◽  
Fixed Carbon ◽  
Experimental Parameters ◽  
Effects Of Temperature

The pyrolysis of three stalk was studied to estimate the effect of pyrolysis conditions on product yield, calorific value and proximate analysis. Heating rate and pyrolysis temperature were the main experimental parameters. According to the test, when the heating rates were at 5, 10 and 15°C/min, the low heating rate reacted more thoroughly, got high yield and kept more energy. As the pyrolysis temperature rising; namely 200,300,400 and 500°C;the fixed carbon and gross calorific value were increasing to be 68% and 24.72 MJ/Kg respectively, but the yield was decreasing.

scholarly journals Evaluation of Non-Isothermal Kinetic Parameters for Pyrolysis of Teak Wood using Model-Fitting Techniques

2021 ◽  
Vol 18 (24) ◽  
pp. 1432
Author(s):  
Adekunle Adeleke ◽  
Peter Ikubanni ◽  
Jamiu Odusote ◽  
Thomas Orhadahwe ◽  
Olumuyiwa Lasode ◽  
...  
Keyword(s):  
Activation Energy ◽  
Weight Loss ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Model Fitting ◽  
Calorific Value ◽  
Wood Dust ◽  
Heating Rates ◽  
Teak Wood ◽  
Isothermal Kinetic

Teak wood is one of the prominently used raw material in the construction industry, thus contributing extremely to the biomass waste available in Nigeria. These wastes are usually used for energy generation that requires upgrade into better fuel before application. Hence, the present study evaluates the non-isothermal kinetic parameters for pyrolysis of teak wood using model-fitting techniques. Teak wood dust was subjected to proximate, ultimate and calorific value analyses based on different ASTM standards. The thermal degradation and decomposition behaviour of the teak wood dust was examined using a thermogravimetric analyzer. Pulverized teak (6.5 mg) was heated from 30 to 800 ºC at varying heating rates (5, 10 and 15 ºC) in an environment where 100 mL/min of nitrogen gas was charged in continuously to maintain an inert condition. Avrami-Erofeev, Ginstling-Broushtein (GB) and Mampel models were used to evaluate the kinetic parameters of the pyrolysis of teak wood dust. The teak wood dust contained 7.25 % moisture, 79.26 % volatile matter (VM), 1.74 % ash and 11.75 % fixed carbon. The calorific value of the wood dust was 18.72 MJ/kg. The results of the thermogravimetric analyses depicted that heating rate has no effect on weight loss during the reactive drying zone. However, as the thermal treatment progressed into the active pyrolysis and passive pyrolysis zones, the weight loss decreased with increase in heating rate.  The devolatilization parameters also increased with heating rates except for the maximum conversion. The results of the kinetic parameters evaluation revealed that the GB model was best fit to evaluate the kinetic parameters of teak in the active pyrolysis zone while GB and Mampel models were considered most appropriate for the evaluation of the kinetic parameters in the passive pyrolysis zone. Model-fitting method has the capacity to capture a wide range of fractional conversion at a glance. HIGHLIGHTS Arrhenius parameters in terms of activation energy and pre-exponential factor for the pyrolysis of teak wood while comparing 4 different model-fitting techniques were obtained The α-temperature plot for solid state reaction of teak wood dust was a bell-shape (sigmoidal model) The Avrami-Erofeev and SSS models were unable to capture the overlapping multiple reactions that took place simultaneously at the active pyrolysis zone Higher energy input is needed for devolatilization of teak wood dust to give 10 - 80 % conversion due to higher activation energy at the active pyrolysis zone Ginstling-Broushtein was found to be the best model for evaluating the kinetic parameters at the active pyrolysis zone as it had the highest R2 value GRAPHICAL ABSTRACT

INVESTIGATION OF THERMAL DEGRADATION OF POULTRY PROCESSING DEWATERED SLUDGE USING THERMOGRAVIMETRIC ANALYSIS METHOD

2015 ◽  
Vol 76 (5) ◽  
Author(s):  
N. Aniza ◽  
S. Hassan ◽  
M. F. M. Nor ◽  
K. E. Kee ◽  
Aklilu T.
Keyword(s):  
Particle Size ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Heating Rate ◽  
Degradation Process ◽  
Heating Rates ◽  
Initial Stage ◽  
Poultry Processing ◽  
Effect Of Particle Size ◽  
Dewatered Sludge

Thermal degradation of Poultry Processing Dewatered Sludge (PPDS) was studied using thermogravimetric analysis (TGA) method. The effect of particle size on PPDS samples and operational condition such as heating rates were investigated. The non-isothermal TGA was run under a constant flow of oxygen at a rate of 30 mL/min with temperature ranging from 30ºC to 800ºC. Four sample particle sizes ranging between 0.425 mm to 2 mm, and heating rate between 5 K/min to 20 K/min were used in this study. The TGA results showed that particle size does not have any significant effect on the thermogravimetry (TG) curves at the initial stage, but the TG curves started to separate explicitly at the second stage. Particle size may affect the reactivity of sample and combustion performance due to the heat transfer and temperature gradient. The TG and peak of derivative thermogravimetry (DTG) curves tend to alter at high temperature when heating rate is increased most likely due to the limitation of mass transfer and the delay of degradation process. 

scholarly journals DTA Evaluation of Spruce Wood Degradation Process

2017 ◽  
Vol 25 (40) ◽  
pp. 41-48
Author(s):  
Ivan Hrušovský ◽  
Peter Rantuch ◽  
Jozef Martinka ◽  
Simona Dzíbelová
Keyword(s):  
Activation Energy ◽  
Room Temperature ◽  
Degradation Process ◽  
Heating Rates ◽  
Wood Degradation ◽  
Wood Sawdust ◽  
Spruce Wood ◽  
Calculated Activation Energy ◽  
Two Stages ◽  
Calculated Activation

Abstract The decomposition stages of spruce wood sawdust were analyzed by means of sequential differential calorimetry. Two stages of decomposition were identified and activation energy of one stage was calculated using the Kissinger method. The DTA was conducted by means of SEDEX safety calorimeter. Sample was analyzed under three heating rates of 10, 20 and 45 °C/h in temperature range from room temperature to 400 °C. The calculated activation energy for the last and most clear decomposition peak was 122.63 KJ/mol. The results are comparable with the data calculated by J.V. Rissanen et al., who calculated activation energy for Spruce hemicellulose as 120 KJ/mol.

Kinetics Study on Non-Isothermal Crystallization of Amorphous Alloy Mg65Cu15Ag10Y10

2011 ◽  
Vol 413 ◽  
pp. 432-438
Author(s):  
Xiao Jun Wang ◽  
Tian Dong Xia ◽  
Xue Ding Chen
Keyword(s):  
Activation Energy ◽  
Amorphous Alloy ◽  
Heating Rate ◽  
Volume Fraction ◽  
Strong Dependence ◽  
Continuous Heating ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Local Activation ◽  
Local Activation Energy

The crystallization kinetics of amorphous alloy Mg65Cu15Ag10Y10has been studied by differential scanning calorimetry in the mode of continuous heating annealing. It is found that both DSC curves and activation energy show a strong dependence on the heating rate. The activation energy for crystallization are determined as 186.1 and 184.4 KJ mol−1for the heating rates β=5-20 Kmin−1, and 107.5 and 110.0 KJmol−1for the heating rates β=20-80Kmin−1, when using the Kissinger equation and the Ozawa equation, respectively. Local activation energy at any volume fraction crystallized was obtained by the general Ozawa's isoconversional method. The average value of local activation energy for heating rates ranging from 5 to 20Kmin−1is 180.9 KJ mol−1and for heating rates ranging between 20 and 80Kmin−1is 110.2 KJ mol−1. Using the Suriñach curve fitting procedure, the kinetics mode was specified. The JMA kinetics is manifested as a rule in the early stages of the crystallization. The JMA exponent,n, initially being larger than 4 and continuously decreases to about 2 along with the development of crystallization. The NGG-like mode dominates in the advanced stages of the transformation. These two modes are mutually independent. The proportion between the JMA-like and the NGG-like modes is related to the heating rate.

scholarly journals A Modified Model for Kinetic Analysis of Petroleum Coke

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Iman Eslami Afrooz ◽  
Dennis Ling Chuan Ching
Keyword(s):  
Activation Energy ◽  
Distribution Function ◽  
Normal Distribution ◽  
Heating Rate ◽  
Reaction Model ◽  
Normal Distribution Function ◽  
Gravimetric Analysis ◽  
Heating Rates ◽  
Shrinking Core ◽  
Volume Reaction

In this study, a nonisothermal kinetics analysis of petcoke was performed at heating rates of 10, 15, and 20°C/min using thermal gravimetric analysis (TGA). The behaviour of petcoke at different gasification stages (dewatering, volatilization, char burning, and burnout) was studied. The effect of heating rate on the activation energy of petcoke gasification was also investigated. The activation energy of petcoke was estimated using different kinetic models that include volume reaction model (VRM), shrinking core model (SCM), random pore model (RPM), Coats and Redfern model (CRM), and normal distribution function (NDF). The NDF model was modified in this study. It was found that the experimental data were best fitted with the modified normal distribution function (MNDF) and SCM. The results also showed that activation energy decreases as heating rate increases, leading to reduction in gasification completion time.

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.

Application of the Master Sintering Curve Theory to Non-Isothermal Sintering of BaTiO3 Ceramics

2005 ◽  
Vol 494 ◽  
pp. 417-422 ◽  
Author(s):  
Maria V. Nikolić ◽  
Vera P. Pavlović ◽  
Vladimir B. Pavlović ◽  
Nebojsa Labus ◽  
B.D. Stojanović
Keyword(s):  
Activation Energy ◽  
Barium Titanate ◽  
Heating Rate ◽  
High Purity ◽  
Master Curve ◽  
Sintering Behavior ◽  
Densification Behavior ◽  
Sintering Process ◽  
Heating Rates ◽  
Temperature Time

In this paper a practical approach to the analysis of sintering of BaTiO3 using the Master Sintering Curve concept has been presented. Non-isothermal sintering of high-purity non-doped BaTiO3 ceramics was monitored using a sensitive dilatometer at three different heating rates (10, 20 and 30 oC/min) up to 1380oC. Densification of BaTiO3 during sintering was analyzed using the Master Curve Sintering Theory. A MSC was defined characterizing the sintering behavior of barium-titanate regardless of the heating rate. Construction of the MSC enabled estimation of the process activation energy. Using defined MSC, densification behavior of BaTiO3 ceramics during sintering can be predicted for arbitrary temperature-time excursions and these predictions can be used in controlling and planning the sintering process of this material.

scholarly journals Kinetic analysis of Wood residues and Gorse (Ulex europaeus) pyrolysis under non-isothermal conditions: A case of study in Bogotá, Colombia

2019 ◽  
Vol 103 ◽  
pp. 02004
Author(s):  
Vivian Beltrán ◽  
Laura V. Martínez ◽  
Andrés López ◽  
María F. Gómez
Keyword(s):  
Activation Energy ◽  
Weight Loss ◽  
Heating Rate ◽  
Heating Rates ◽  
Levelized Cost Of Electricity ◽  
Ulex Europaeus ◽  
Wood Residues ◽  
Biomass Materials ◽  
Energy Activation ◽  
Maximum Weight Loss

Thermal degradation and kinetic for biomass materials wood residues and Gorse (Ulex europaeus) have been evaluated under pyrolysis (N2) conditions, using a non-isothermal thermogravimetric method (TGA) from 25°C to 900°C at different heating rates of 10, 20, 30 and 40°C min-1. In DTG curves the temperature peaks at maximum weight loss rate changed with increasing heating rate. The maximum rate of weight loss (%s-1) was obtained at a heating rate of 40°C/min of 0,38 and 0,46 (%s-1) for wood residues and Gorse, respectively. Activation energy calculations were based on selected non-isothermal methods (Kissinger, FWO, KAS, and Starink). For Gorse, the energy activation was 195.41, 194.44, 214.39 and 179.42 kJmol-1 by Kissinger, FWO, KAS, and Starink methods, respectively. In the other hand, the energy activation for wood residues was 176.03, 221.75, 243.08 and 198.26 kJmol-1 by Kissinger, FWO, KAS, and Starink methods, respectively. The results showed that Gorse has a lower activation energy than wood residues, which represents a great potential to be used as a feedstock in thermochemical technologies. The Levelized Cost of Electricity (LCOE) was calculated for gasification of wood residues and Gorse, which was 186 and 169 USD/MWh, respectively.

Thermogravimetric Analysis of Superabsorbing Polyacrylic Hydrogel

2005 ◽  
Vol 494 ◽  
pp. 193-198 ◽  
Author(s):  
B. Janković ◽  
B. Adnadjević ◽  
J. Jovanović ◽  
D. Minić ◽  
Lj. Kolar-Anić
Keyword(s):  
Activation Energy ◽  
Distribution Function ◽  
Thermogravimetric Analysis ◽  
Weibull Distribution ◽  
Heating Rate ◽  
Rate Constant ◽  
Heating Rates ◽  
Exponential Factor ◽  
Weibull Distribution Function ◽  
Thermogravimetric Curve

The thermogravimetric analysis of superabsorbing polyacrylic hydrogel dehydration, performed under non-isothermal conditions at different heating rates was discussed. Particularly, the influence of the heating rate on the obtained results is given in detail. For this purpose the Weibull distribution function was applied. The thermogravimetric curve when the heating rate tends to zero was evaluated. The activation energy E = 63 kJ/mol, pre-exponential factor A = 2.97 × 108 min−1, and rate constant k = 2.76 × 10−3 min−1 were determined on the basis of this curve.

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