An FT-IR Method for Performing Dynamic Kinetic Experiments

1988 ◽  
Vol 42 (4) ◽  
pp. 655-658 ◽  
Author(s):  
Randy W. Snyder ◽  
C. Wade Sheen
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Heating Rates ◽  
Calculated Activation Energy ◽  
Ft Ir ◽  
Calculated Activation

A method is shown for the determination of kinetic parameters from dynamic FT-IR experiments. The effect heating rate has on the reproducibility of the calculated activation energy is discussed. The curing of PMDA/ODA polyimide at several heating rates is given as an example.

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.

Calculations of activation energy and frequency factors for corn leafs pyrolysis using excel solver: new concept

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Omar Salim Al-Ayed ◽  
Mohammad Waleed Amer ◽  
Sura Al-Harahshah ◽  
Birgit Maaten ◽  
Muhammad Sajjad Ahmed
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Frequency Factor ◽  
Heating Rates ◽  
First Order ◽  
First Order Kinetics ◽  
Calculated Activation Energy ◽  
Apparent Activation Energies ◽  
Excel Solver ◽  
Calculated Activation

Abstract Thermal degradations of biomass corn leaves were studied for kinetic modeling. Thermogravimetric-differential analyzer runs at 5, 10, 20, and 30 °C min−1 heating rates were employed. Apparent activation energy and frequency factor values were calculated for first-order kinetics using several procedures. The procedure of Coats and Redfern showed 28.89 to 31.78 kJ mol−1 apparent activation energy and 15.5 to 157.12 min−1 frequency factor, respectively. Calculation of the apparent activation energy and frequency factor using Kissinger–Akahira–Sunose procedure gave 229.9–364.2 kJ/mol and 8.567 × 1023 and 1.13 × 1031 (min−1), respectively as the conversion increased from 0.1 to 0.9. The newly introduced excel solver procedure indicates a distribution activation energy over the entire range of conversion. For first-order reaction kinetics, the calculated apparent activation energy magnitudes ranged between 5.0 kJ mol−1 with frequency factor equals to 0.239 and 196.2 kJ mol−1 with frequency factor 2.89 × 1012 in the studied range. The low or high magnitudes of the calculated activation energy are not associated with a particular value of the conversion. The calculated apparent activation energies are related to the direct solution of the simultaneous equations that constitute the basis of the excel solver.

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

scholarly journals Non-Isothermal Sublimation Kinetics of 2,4,6-Trinitrotoluene (TNT) Nanofilms

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1163 ◽  
Author(s):  
Walid Hikal ◽  
Brandon Weeks
Keyword(s):  
Activation Energy ◽  
Analytical Techniques ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Absorbance Spectroscopy ◽  
Calculated Activation Energy ◽  
Sublimation Kinetics ◽  
Sublimation Rates ◽  
First Time ◽  
Kinetics Of

Non-isothermal sublimation kinetics of low-volatile materials is more favorable over isothermal data when time is a crucial factor to be considered, especially in the subject of detecting explosives. In this article, we report on the in-situ measurements of the sublimation activation energy for 2,4,6-trinitrotoluene (TNT) continuous nanofilms in air using rising-temperature UV-Vis absorbance spectroscopy at different heating rates. The TNT films were prepared by the spin coating deposition technique. For the first time, the most widely used procedure to determine sublimation rates using thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) was followed in this work using UV-Vis absorbance spectroscopy. The sublimation kinetics were analyzed using three well-established calculating techniques. The non-isothermal based activation energy values using the Ozawa, Flynn–Wall, and Kissinger models were 105.9 ± 1.4 kJ mol−1, 102.1 ± 2.7 kJ mol−1, and 105.8 ± 1.6 kJ mol−1, respectively. The calculated activation energy agreed well with our previously reported isothermally-measured value for TNT nanofilms using UV-Vis absorbance spectroscopy. The results show that the well-established non-isothermal analytical techniques can be successfully applied at a nanoscale to determine sublimation kinetics using absorbance spectroscopy.

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.

Research on Pyrolysis Kinetics of Shenhua Coal and Direct Liquefaction Residue

2012 ◽  
Vol 550-553 ◽  
pp. 2758-2762 ◽  
Author(s):  
Xi Jie Chu ◽  
Yong Gang Wang ◽  
Li Hong Zhao
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Coal Pyrolysis ◽  
Pyrolysis Kinetics ◽  
Differential Heating ◽  
Pyrolysis Behavior ◽  
Direct Liquefaction ◽  
Kinetics Of

The pyrolysis tests of Shenhua coal and Shenhua direct liquefaction residue have been carried out using thermogravimetric at the differential heating rate. The kinetic parameters k and E were calculated using DAEM method. Results show DAME model can describe the pyrolysis behavior of Shenhua coal within the range of 20% to 95%, the activation energy of coal pyrolysis ranges from 53.98 to 279.38 kJ/mol, and DAME model can describe the behavior of Shenhua direct liquefaction residue within the range of 10% to 80%, the activation energy of residue pyrolysis is about 170 kJ/mol. The results of which are basically consistent with the experimental data.

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

2006 ◽  
Vol 116-117 ◽  
pp. 54-57 ◽  
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.

Annealing Behavior of the Compressed AZ31 Magnesium Alloy with Different Strain

2007 ◽  
Vol 546-549 ◽  
pp. 267-270
Author(s):  
Tian Mo Liu ◽  
Pan Xiao ◽  
Fu Sheng Pan ◽  
Qing Liu
Keyword(s):  
Activation Energy ◽  
Annealing Temperature ◽  
Hardness Test ◽  
Test Results ◽  
Annealing Behavior ◽  
Different Temperatures ◽  
Calculated Activation Energy ◽  
Calculated Activation ◽  
Crystallographic Orientations ◽  
Microhardness Tester

The cold-compressed AZ31 magnesium alloys with different (2.5%, 5%, 7.5%, 10%, 12.5% and 15%) were annealed at different temperatures (573, 623 and 673K) for different time. With aid of the optical microscopy, and microhardness tester, the microstructural evolution during annealing at different temperature of the compressed AZ31 has been investigated. The microstructural characterized results were further related to the hardness test results and the calculated activation energy. The results showed that for the compressed AZ31, the recrystallization can occur on the samples with the strain just above 10% and the deformation twinning plays an important role on the nucleation and grain growth of the recrystallization. It was found that the twinning boundary was the location of the recrystallization nuclei and a lot of recrystallized grains with equiaxed shape were found along the twinning boundaries. The relationships among the nuclei orientations and the crystallographic orientations on both sides of the twining boundary have been statistically investigated. The effects of the compressed strain and the annealing temperature on annealing behavior were also discussed based on the experimental results.

scholarly journals Optimized Heating Rate and Soot-catalyst Ratio for Soot Oxidation over MoO3 Catalyst

2017 ◽  
Vol 12 (3) ◽  
pp. 408 ◽  
Author(s):  
Congwei Mei ◽  
Deqing Mei ◽  
Shan Yue ◽  
Zong Chen ◽  
Yinnan Yuan
Keyword(s):  
Heating Rate ◽  
Soot Oxidation ◽  
Transfer Effect ◽  
Reaction Engineering ◽  
Heating Rates ◽  
Thermogravimetric Analyzer ◽  
Ft Ir ◽  
Surface Microstructures ◽  
And Diffusion ◽  
Lower Heating

MoO3 is now utilized as a promising catalyst due to its high activity and favorable mobility at low temperature. Its spectral data and surface microstructures were characterized by Fourier transform infrared spectra (FT-IR) and Field emission scanning electron microscope (FESEM). Thermo-analysis of the carbon black was performed over nano-MoO3 catalyst in a thermogravimetric analyzer (TGA) at various heating rates and soot-catalyst ratios. Through the analysis of kinetic parameters, we found that the heat transfer effect and diffusion effect can be removed by setting lower heating rates and soot-catalyst ratios. Therefore, a strategy for selecting proper thermogravimetric parameters were established, which can contribute to the better understanding of thermo-analytical process. Copyright © 2017 BCREC Group. All rights reservedReceived: 4th December 2016; Revised: 13rd June 2017; Accepted: 9th April 2017; Available online: 27th October 2017; Published regularly: December 2017How to Cite: Mei, C., Mei, D., Yue, S, Chen, Z., Yuan, Y. (2017). Optimized Heating Rate and Soot-catalyst Ratio for Soot Oxidation over MoO3 Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (3): 408-414 (doi:10.9767/bcrec.12.3.845.408-414 

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