Investigating the pyrolysis kinetics of Pinus sylvestris using thermogravimetric analysis

Thermogravimetric analyses of Pinus sylvestris from Xinxiang were performed to investigate its kinetic characteristics, which could provide information for industrial applications. Thermal degradation experiments were conducted at various heating rates of 10 °C/min, 20 °C/min, and 60 °C/min using a thermogravimetric analysis-differential scanning calorimetry (TG-DSC) analyzer with an inert environment. The peak pyrolysis temperatures of the three major components (hemicellulose, cellulose, and lignin) were predicted by the Kissinger-Kai method, and activation energy values (Eα) were calculated. The Eα of Pinus sylvestris was also estimated by two model-free methods. The decomposition reactions of hemicellulose, cellulose, and lignin at different temperatures were the main reason for fluctuations in Eα. The time for heat transfer was less sufficient at a high heating rate compared with that at a low heating rate, which caused the temperature gradients in the samples. Therefore, the temperature of maximum exothermic peaks was higher than the maximum pyrolysis temperature. This kinetic study could be useful for providing guidance for optimizing the biomass pyrolysis process.

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Thermal Decomposition Kinetic Study of Non-Recyclable Paper and Plastic Waste by Thermogravimetric Analysis

ChemEngineering ◽

10.3390/chemengineering5030054 ◽

2021 ◽

Vol 5 (3) ◽

pp. 54

Author(s):

Ahmad Mohamed S. H. Al-Moftah ◽

Richard Marsh ◽

Julian Steer

Keyword(s):

Power Generation ◽

Thermal Decomposition ◽

Thermogravimetric Analysis ◽

Thermal Treatment ◽

Solid Waste ◽

Heating Rate ◽

Heating Rates ◽

Exponential Factor ◽

Model Free ◽

Treatment Processes

The global net emissions of the Kyoto Protocol greenhouse gases (GHG), such as carbon dioxide (CO2), fluorinated gases, methane (CH4), and nitrous oxide (N2O), remain substantially high, despite concerted efforts to reduce them. Thermal treatment of solid waste contributes at least 2.8–4% of the GHG in part due to increased generation of municipal solid waste (MSW) and inefficient treatment processes, such as incineration and landfill. Thermal treatment processes, such as gasification and pyrolysis, are valuable ways to convert solid materials, such as wastes into syngas, liquids, and chars, for power generation, fuels, or for the bioremediation of soils. Subcoal™ is a commercial product based on paper and plastics from the source segregated waste that is not readily recyclable and that would otherwise potentially find its way in to landfills. This paper looks at the kinetic parameters associated with this product in pyrolysis, gasification, and combustion conditions for consideration as a fuel for power generation or as a reductant in the blast furnace ironmaking process. Thermogravimetric Analysis (TGA) in Nitrogen (N2), CO2, and in air, was used to measure and compare the reaction kinetics. The activation energy (Ea) and pre-exponential factor A were measured at different heating rates using non-isothermal Ozawa Flynn Wall and (OFW) and Kissinger-Akahira-Sonuse (KAS) model-free techniques. The TGA curves showed that the thermal degradation of Subcoal™ comprises three main processes: dehydration, devolatilization, and char and ash formation. In addition, the heating rate drifts the devolatilization temperature to a higher value. Likewise, the derivative thermogravimetry (DTG) results stated that Tm degradation increased as the heating rate increased. Substantial variance in Ea was noted between the four stages of thermal decomposition of Subcoal™ on both methods. The Ea for gasification reached 200.2 ± 33.6 kJ/mol by OFW and 179.0 ± 31.9 kJ/mol by KAS. Pyrolysis registered Ea values of 161.7 ± 24.7 kJ/mol by OFW and 142.6 ± 23.5 kJ/mol by KAS. Combustion returned the lowest Ea values for both OFW (76.74 ± 15.4 kJ/mol) and KAS (71.0 ± 4.4 kJ/mol). The low Ea values in combustion indicate shorter reaction time for Subcoal™ degradation compared to gasification and pyrolysis. Generally, TGA kinetics analysis using KAS and OFW methods show good consistency in evaluating Arrhenius constants.

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Effects of additives on the cure kinetics of vinyl ester pultrusion resins

Journal of Composite Materials ◽

10.1177/00219983211001528 ◽

2021 ◽

pp. 002199832110015

Author(s):

Alexander Vedernikov ◽

Yaroslav Nasonov ◽

Roman Korotkov ◽

Sergey Gusev ◽

Iskander Akhatov ◽

...

Keyword(s):

Vinyl Ester ◽

Mean Squared Error ◽

Cure Kinetics ◽

Zinc Stearate ◽

Heating Rates ◽

Scanning Calorimetry ◽

Different Temperatures ◽

Predicted Values ◽

Kinetics Of ◽

Final Degree

Pultrusion is a highly efficient composite manufacturing process. To accurately describe pultrusion, an appropriate model of resin cure kinetics is required. In this study, we investigated cure kinetics modeling of a vinyl ester pultrusion resin (Atlac 430) in the presence of aluminum hydroxide (Al(OH)3) and zinc stearate (Zn(C18H35O2)2) as processing additives. Herein, four different resin compositions were studied: neat resin composition, composition with Al(OH)3, composition comprising Zn(C18H35O2)2, and composition containing both Al(OH)3 and Zn(C18H35O2)2. To analyze each composition, we performed differential scanning calorimetry at the heating rates of 5, 7.5, and 10 K/min. To characterize the cure kinetics of Atlac 430, 16 kinetic models were tested, and their performances were compared. The model based on the [Formula: see text]th-order autocatalytic reaction demonstrated the best results, with a 4.5% mean squared error (MSE) between the experimental and predicted data. This study proposes a method to reduce the MSE resulting from the simultaneous melting of Zn(C18H35O2)2. We were able to reduce the MSE by approximately 34%. Numerical simulations conducted at different temperatures and pulling speeds demonstrated a significant influence of resin composition on the pultrusion of a flat laminate profile. Simulation results obtained for the 600 mm long die block at different die temperatures (115, 120, 125, and 130 °C) showed that for a resin with a final degree of cure exceeding 95% at the die exit, the maximum difference between the predicted values of pulling speed for a specified set of compositions may exceed 1.7 times.

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

Jurnal Teknologi ◽

10.11113/jt.v76.5522 ◽

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.

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Measurement and Evaluation of Calorimetric Descriptors for the Suitability for Evolutionary High-Throughput Material Development

Metals ◽

10.3390/met9020149 ◽

2019 ◽

Vol 9 (2) ◽

pp. 149 ◽

Cited By ~ 2

Author(s):

Anastasiya Toenjes ◽

Heike Sonnenberg ◽

Christina Plump ◽

Rolf Drechsler ◽

Axel von Hehl

Keyword(s):

Heating Rate ◽

High Throughput ◽

Macro Level ◽

Heating Rates ◽

Scanning Calorimetry ◽

Characterization Methods ◽

Material Development ◽

First Results ◽

Novel Method ◽

Measurement And Evaluation

A novel method for evolutionary material development by using high-throughput processing is established. For the purpose of this high-throughput approach, spherical micro samples are used, which have to be characterized, up-scaled to macro level and valued. For the evaluation of the microstructural state of the micro samples and the associated micro-properties, fast characterization methods based on physical testing methods such as calorimetry and universal microhardness measurements are developed. Those measurements result in so-called descriptors. The increase in throughput during calorimetric characterization using differential scanning calorimetry is achieved by accelerating the heating rate. Consequently, descriptors are basically measured in a non-equilibrium state. The maximum heating rate is limited by the possibility to infer the microstructural state from the calorimetric results. The substantial quality of the measured descriptors for micro samples has to be quantified and analyzed depending on the heating rate. In this work, the first results of the measurements of calorimetric descriptors with increased heating rates for 100Cr6 will be presented and discussed. The results of low and high heating rates will be compared and analyzed using additional microhardness measurements. Furthermore, the validation of the method regarding the suitability for the evolutionary material development includes up-scaling to macro level and therefore different sample masses will be investigated using micro and macro samples during calorimetry.

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XPS and Electron Microscopy Study of Oxide-Scale Evolution on Ignition Resistant Mg-3Ca Alloy at Low and High Heating Rates

Experimental Results ◽

10.1017/exp.2020.41 ◽

2020 ◽

Vol 1 ◽

Author(s):

L. A. Villegas-Armenta ◽

R. A. L. Drew ◽

M. O. Pekguleryuz

Keyword(s):

Oxide Scale ◽

Heating Rate ◽

Photoelectron Spectroscopy ◽

Microscopy Study ◽

Electron Microscopy Study ◽

High Heating Rate ◽

Heating Rates ◽

Oxide Interface ◽

Protective Oxide ◽

High Heating

AbstractEarlier work by the authors suggested that the formation of molten eutectic regions in Mg-Ca binary alloys caused a discrepancy in ignition temperature when different heating rates are used. This effect was observed for alloys where Ca content is greater than 1 wt%. In this work, the effect of two heating rates (25 °C/min and 45 °C/min) on the ignition resistance of Mg-3Ca is evaluated in terms of oxide growth using X-ray Photoelectron Spectroscopy. It is found that the molten eutectic regions develop a thin oxide scale of ~100 nm rich in Ca at either heating rate. The results prove that under the high heating rate, solid intermetallics are oxidized forming CaO nodules at the metal/oxide interface that eventually contribute to the formation of a thick and non-protective oxide scale in the liquid state.

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Effects of Heating Rate on Formation of Globular and Acicular Austenite during Reversion from Martensite

Metals ◽

10.3390/met9020266 ◽

2019 ◽

Vol 9 (2) ◽

pp. 266 ◽

Cited By ~ 3

Author(s):

Xianguang Zhang ◽

Goro Miyamoto ◽

Yuki Toji ◽

Tadashi Furuhara

Keyword(s):

Heating Rate ◽

High Temperatures ◽

The Other ◽

Growth Mode ◽

High Heating Rate ◽

Heating Rates ◽

Other Hand ◽

High Heating ◽

Martensite Matrix

The effects of heating rate on the formation of acicular and globular austenite during reversion from martensite in Fe–2Mn–1.5Si–0.3C alloy have been investigated. It was found that a low heating rate enhanced the formation of acicular austenite, while a high heating rate favored the formation of globular austenite. The growth of acicular γ was accompanied by the partitioning of Mn and Si, while the growth of globular γ was partitionless. DICTRA simulation revealed that there was a transition in growth mode from partitioning to partitionless for the globular austenite with an increase in temperature at high heating rate. High heating rates promoted a reversion that occurred at high temperatures, which made the partitionless growth of globular austenite occur more easily. On the other hand, the severer Mn enrichment into austenite at low heating rate caused Mn depletion in the martensite matrix, which decelerated the reversion kinetics in the later stage and suppressed the formation of globular austenite.

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Thermal Behavior of Sweet Potato Starch by Non-Isothermal Thermogravimetric Analysis

Materials ◽

10.3390/ma12050699 ◽

2019 ◽

Vol 12 (5) ◽

pp. 699 ◽

Cited By ~ 8

Author(s):

Ying Liu ◽

Liutao Yang ◽

Chunping Ma ◽

Yingzhe Zhang

Keyword(s):

Thermogravimetric Analysis ◽

Thermal Degradation ◽

Sweet Potato ◽

Degradation Kinetics ◽

Potato Starch ◽

Activation Energies ◽

Thermal Degradation Kinetics ◽

Heating Rates ◽

Scanning Calorimetry ◽

Sweet Potato Starch

In this study, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) methods were used to study the structure, the thermal degradation kinetics, and the thermogram of sweet potato starch, respectively. The thermal decomposition kinetics of sweet potato starch was examined within different heating rates in a nitrogen atmosphere. Different models of kinetic analysis were used to calculate the activation energies using the thermogravimetric data of the thermal degradation process. The activation energies got from Kissinger, Flynn–Wall–Ozawa, and Šatava–Šesták models were 173.85, 174.87, and 174.34 kJ·mol−1, respectively. Thermogravimetry–Fourier transform infrared spectroscopy (TG-FTIR) analysis showed that the main pyrolysis products included water, carbon dioxide, and methane.

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

Waste Management & Research ◽

10.1177/0734242x19897814 ◽

2020 ◽

Vol 38 (1_suppl) ◽

pp. 77-85 ◽

Cited By ~ 8

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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Determination of Solidification Parameters Used for the Prediction of the Thixoformability of Several Steel Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.116-117.54 ◽

2006 ◽

Vol 116-117 ◽

pp. 54-57 ◽

Cited By ~ 4

Author(s):

Jacqueline Lecomte-Beckers ◽

Ahmed Rassili ◽

Marc Robelet ◽

Claude Poncin ◽

R. Koeune

Keyword(s):

Differential Scanning Calorimetry ◽

Heating Rate ◽

Liquid Fraction ◽

Heating Rates ◽

Scanning Calorimetry ◽

Steel Alloys ◽

Fraction Versus ◽

Solidification Parameters ◽

Industrial Heating

This paper focuses on the liquid fraction curves of several steels and the correlation between liquid fraction, temperature and heating rate. The work has been performed along two main axes. First, the solid fraction versus temperature has been obtained experimentally by differential scanning calorimetry (DSC), limited to low heating rates. Then, a shift of the liquid fraction curves has been noticed at high industrial heating rates. The quantification of this effect could not be carried out by DSC and required the elaboration of another experimental device.

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Study on the Pyrolysis Kinetics of HCl-Pretreated Soybean Stalk

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.953-954.261 ◽

2014 ◽

Vol 953-954 ◽

pp. 261-266

Author(s):

Dong Yu Chen ◽

Yan Qing Hu ◽

Qing Yu Liu

Keyword(s):

Heating Rate ◽

Temperature Increase ◽

Loss Rate ◽

High Efficiency ◽

Three Dimensional ◽

Pyrolysis Kinetics ◽

Heating Rates ◽

Acid Washing ◽

Shoulder Peak ◽

Kinetics Of

To study the influences of the acid-washing on the characteristics of soybean stalk pyrolysis , and search the high-efficiency catalyst for biomass pyrolysis, pyrolysis experiments of soybean stalk pretreated by 0.1mol/L HCl acid solution were performed by nonisothermal thermogravimetric analysis (TGA) at five different heating rates. The results showed the pyrolysis process of HCl-washed soybean stalk can be separated into four stages (water loss, depolymeri-zation and vitrification, thermal decomposition, and carbonization). At the same heating rate, the maximum pyrolysis rate of HCl-washed is larger than untreated soybean stalk, but the corresponding temperature is higher. All the DTG (differential thermogravimetric) curveas appear a smaller shoulder peak respectively. With the heating rate increasing, the main pyrolysis zone of the TG (thermogravimetric) and DTG curves move to the high-temperature direction, and the maximum pyrolysis rate and its corresponding temperature increase too. HCl-wahsed makes the weight loss rate of the final temperature increase 5% approximately. The value area of activation energy of the main pyrolysis area is 140.19~174.59 kJ/mol calculated by the method of Ozawa. The Šatava method inferred the most possible mechanism function of HCl-wahsed soybean stalk is Zhuralev-Lesakin-Tempelman equation, which is three-dimensional diffusion.

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