Improved Method for the Determination of Kinetic Parameters from Non-isothermal Thermogravimetric Analysis (TGA) Data

Hillier, James L.; Bezzant, Trent; Fletcher, Thomas H.

doi:10.1021/ef1001265

Cited by 36 publications

(21 citation statements)

References 15 publications

(18 reference statements)

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“…Numerous methods to study the kinetics of the TG process, such as differential methods, integration methods, multi‐heating rates methods, differential subduction methods, maximum rate methods, initial rate methods, etc. were developed 21. In this work, the Satava‐Sestak method was applied to study the kinetics of the oxidation reaction of boron because of its accuracy and convenience.…”

Section: Resultsmentioning

confidence: 99%

Effect of Initial Oxide Layer on Ignition and Combustion of Boron Powder

Ao¹,

Wang²,

Li³

et al. 2013

Propellants Explo Pyrotec

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Only few data exist for experimental studies on ignition and combustion of boron particles with initial oxide thickness. The oxidation, ignition and combustion characteristics including the onset temperatures, weight gain, apparent activation energy, emission spectra during combustion, and ignition delay time of crystalline boron powders with different initial oxide thickness (x0) were studied by a laser ignition and thermogravimetric (TG) analyses. Simulations of the kinetics of oxide layer during boron ignition were conducted using a common model. The results indicated that the onset temperature was approximately 775 °C, independent of x0. The total weight gain decreased with increasing x0, whereas the weight gain at 775 °C did not change. The apparent activation energy was found to be insensitive to x0 and had a constant value of about 210 kJ mol−1. The intensity of the emission spectra gradually decreased while the ignition delay time increased with increasing x0. Numerical simulation showed that the removal rate of oxide layer enhanced with increasing x0. The experimental results revealed that the oxidation of boron powder was no diffusion‐controlled process at low temperatures. But the diffusion of oxygen could become important to the oxidation reaction at high temperatures

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Section: Resultsmentioning

confidence: 99%

Effect of Initial Oxide Layer on Ignition and Combustion of Boron Powder

Ao¹,

Wang²,

Li³

et al. 2013

Propellants Explo Pyrotec

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“…[51] The capacity of SA to optimize the kinetic parameters of combustion has been presented in the literature. [37,38,51,52] 2 | MATERIAL AND METHODOLOGY…”

Section: Thermal Decomposition Kineticsmentioning

confidence: 99%

Kinetic and thermodynamic modelling of thermal decomposition of bitumen under high pressure enhanced with simulated annealing and artificial intelligence

et al. 2021

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Thermogravimetric analysis (TGA) of energy resources including bitumen provides kinetic parameters, which can be applied in design and simulation of processes for thermal recovery and conversion. In this investigation, pressurized non‐isothermal decomposition of bitumen under inert environment has been studied. The kinetic parameters were calculated at different pressures (0.1, 0.5, and 1 MPa) and heating rates (10, 20, and 30°C/min) using the differential method. The parameters were later optimized using simulated annealing (SA) optimization algorithm. The results were subsequently validated by comparing the predicted conversion (α) with those of artificial neural network (ANN). Thermodynamic parameters (enthalpy, entropy, and Gibb's free energy) were also calculated using the optimized kinetic parameters. The TGA results show that weight loss and thermal conversion decreased as the total pressure increased from 0.1–1 MPa, at all heating rates. Conversely, the thermal conversion rate (dα/dT) was observed to first decrease with increasing pressure (0.1–1 MPa) within the low temperature oxidation (LTO) and fuel deposition (FD) regions. In contrast, it increased with increasing total pressure within the high temperature oxidation (HTO) region. Furthermore, it was observed that the activation energy (Ea) increased with increasing pressures at all heating rates, while the frequency factor (A) was independent of the pressure or the heating rates. In addition, the thermodynamic parameters tend to increase with increasing pressure. Ultimately, the results established that the SA algorithm could be used to enhance the performance of the differential modelling method in calculating kinetic parameters and predicting the conversion.

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“…An alternative integral method yielded much narrower linear temperature ranges and was thus discarded. Equation ( 2) can be converted into a logarithmic form to determine the activation energy values from the slope of the vs. 1/T plot [22]:…”

Section: Calculation Of Activation Energiesmentioning

confidence: 99%

Molecular scale studies that inform trace element sulfide evaporation and atomization behavior during coal combustion

Artemyeva

Seames

Pierce

et al. 2017

Fuel

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Understanding the chemical mechanisms of trace element (TE) evolution is essential for accurate modeling of coal combustion. A novel graphite furnace atomic absorption spectrometry (GFAAS) method was used to simulate the evaporation and atomization behavior of TE sulfides (arsenic, antimony and selenium) in the two distinct microenvironments that mineral inclusions and exclusions experience during the onset of coal combustion. Additional insights were obtained using thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) Potassium polysulfide was used as an additive to water to facilitate the dissolution of all three TE sulfides. TE sulfides in inclusions were studied by adding the test mixture to a graphite tube in a reducing (anaerobic) micro-environment whereas the TE evolution in excluded sulfide minerals was studied by blocking the graphite tube surface with an inert ZrO 2 or WO 3 coating. Arsenic sulfide, As 2 S 3 , exhibits a lower Arrhenius activation energy of atomization, E a , than that of the corresponding oxide in both mineral inclusions and exclusions, apparently because of the availability of a specific facile path to atomization. A higher E a was observed for antimony sulfide, Sb 2 S 3 , than that of the corresponding oxide from inclusions and is most likely due to its strong binding affinity to the carbon tube surface. The low GFAAS signal of selenium sulfide suggests the formation of molecular clusters, e.g., Se 2 , Se 8 or similar mixed clusters with sulfur atoms prior to vaporization, an effect not observed for selenium oxide evaporation. For all three

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Improved Method for the Determination of Kinetic Parameters from Non-isothermal Thermogravimetric Analysis (TGA) Data

Cited by 36 publications

References 15 publications

Effect of Initial Oxide Layer on Ignition and Combustion of Boron Powder

Effect of Initial Oxide Layer on Ignition and Combustion of Boron Powder

Kinetic and thermodynamic modelling of thermal decomposition of bitumen under high pressure enhanced with simulated annealing and artificial intelligence

Molecular scale studies that inform trace element sulfide evaporation and atomization behavior during coal combustion

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