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 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.

A method of preparation of x-casein and some observations on its nature

1962 ◽  
Vol 29 (2) ◽  
pp. 163-171 ◽  
Author(s):  
G. C. Cheeseman
Keyword(s):  
Activation Energy ◽  
Calcium Ions ◽  
Ion Concentration ◽  
Gel Formation ◽  
Protein Nitrogen ◽  
First Order ◽  
Electrophoretic Patterns ◽  
Calculated Activation Energy ◽  
Milk Coagulation ◽  
Calculated Activation

SummaryDetails are given of the method used in this laboratory for the preparation of k-casein. The recovery is about 25% and the material has a purity, estimated from electrophoretic patterns, of about 90% with β-casein as the main contaminant. Higher temperatures and lower ion concentration caused precipitation of k-casein in the presence of calcium ions, 0·1m-acetate buffer at pH 6·5 being sufficient to stabilize a 0·5% solution in the presence of 0·01–0·2m-CaCl2 at 20 and 30°C but not at all calcium concentrations at 40°C. It was also found that solutions of para-k-casein did not aggregate in the presence of concentrations of electrolytes above about 0·25m.The rate of release of non-protein nitrogen and decline in viscosity during the enzymic stage of gel formation in solutions of k-casein and rennin had similar apparent first order constants (0·087 ± 0·03 min—1 and 0·086 ± 0·021 min—1, respectively, at 25°C). A gel could be formed by rennin action in a solution containing as little as 6·25mg of the protein per litre. In the non-enzymic stage of gelling of k-casein solutions the calculated activation energy over the range of 20–40°C was much lower than that obtained from the non-enzymic stage of milk coagulation.

AN INDEPENDENT METHOD FOR OBTAINING THE ACTIVATION ENERGY OF THERMOLUMINESCENCE GLOW PEAKS

2004 ◽  
Vol 18 (20n21) ◽  
pp. 2877-2885 ◽  
Author(s):  
M. S. RASHEEDY
Keyword(s):  
Activation Energy ◽  
Glow Peak ◽  
Independent Method ◽  
Heating Rates ◽  
First Order ◽  
First Order Kinetics ◽  
General Order ◽  
Luminescence Process ◽  
The Common ◽  
Kinetics Order

The activation energy E (eV) of the first-order thermoluminescence (TL) glow peak is currently obtained using a two heating rates method. However, this method having the common drawback, that it assumes the first-order kinetics in the luminescence process. In the present work, an equation is suggested to determine the activation energy E (eV) of any glow peak, independent on the kinetics order of the process. To apply this method, three heating rates (β1,β2,β3), the corresponding peak temperatures (T1,T2,T3) and intensities (I1,I2,I3) of the isolated glow peaks are required. The applicability of the suggested method is demonstrated here by taking some numerically computed first-, second- and general-order TL glow peaks.

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 Effect of CaO on catalytic combustion of semi-coke

2021 ◽  
Vol 10 (1) ◽  
pp. 011-020
Author(s):  
Luyao Kou ◽  
Junjing Tang ◽  
Tu Hu ◽  
Baocheng Zhou ◽  
Li Yang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Combustion Rate ◽  
Activation Energies ◽  
Combustion Reaction ◽  
Tg Analysis ◽  
Conversion Rates ◽  
Apparent Activation Energies ◽  
Ozawa Integral Method ◽  
Addition Amount

Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.

APPLICATION OF CVD DIAMOND FILMS FOR UV THERMOLUMINESCENCE DOSIMETER

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1003-1007 ◽  
Author(s):  
J. AHN ◽  
B. GAN ◽  
Q. ZHANG ◽  
S. F. YOON ◽  
V. LIGATCHEV ◽  
...  
Keyword(s):  
Activation Energy ◽  
Glow Curve ◽  
Diamond Films ◽  
Frequency Factor ◽  
Cvd Diamond ◽  
Order Kinetic ◽  
First Order ◽  
Order Kinetic Model ◽  
Ionizing Radiations ◽  
Trap Activation

This study presents the investigation of CVD diamond for the application of an UV TL dosimeter. A 9-μm-thick film used in this study presents a TL glow curve with a well-defined first-order kinetic peak (at about 273 K), which norm ally presents in the glow curve from ionizing radiations, is not observed. By fitting the glow curve to a first-order kinetic model, the trap activation energy E t = 0.95 eV and frequency factor s = 5.6 x 106 s -1 have been resolved.

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.

Skeletal isomerization of cyclohexene on Al2O3 and AlPO4–Al2O3 catalysts

1984 ◽  
Vol 62 (8) ◽  
pp. 1455-1458 ◽  
Author(s):  
J. M. Campelo ◽  
A. Garcia ◽  
J. M. Gutierrez ◽  
D. Luna ◽  
J. M. Marinas
Keyword(s):  
Rate Constants ◽  
Reaction Pathway ◽  
Acid Sites ◽  
Skeletal Isomerization ◽  
Irreversible Adsorption ◽  
First Order ◽  
First Order Kinetics ◽  
Selectivity Studies ◽  
Apparent Activation Energies ◽  
Competitive Products

Cyclohexene skeletal isomerization, in a microcatalytic pulse reactor, was investigated using Al2O3 and AlPO4–Al2O3 as catalysts. Apparent rate constants and apparent activation energies were calculated according to the kinetic model of Bassett–Habgood. Selectivity studies concluded that 1-MCP and 3-MCP were competitive products with a first-order kinetics. The rate constants as well as the selectivity at 1-MCP increase with an increase in the number and strength of stronger acid sites, measured by means of the irreversible adsorption of aniline in cyclohexane, at 298 K, using a spectrophotometric method. The parallel reaction pathway, proposed for AlPO4 catalysts, agrees with both the observed rates and selectivities using Al2O3 and AlPO4–Al2O3 catalysts.

THE KINETICS OF CUPRENE GROWTH

1950 ◽  
Vol 28b (7) ◽  
pp. 358-372
Author(s):  
Cyrias Ouellet ◽  
Adrien E. Léger
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Apparent Activation Energy ◽  
Copper Catalyst ◽  
Maximum Velocity ◽  
Static System ◽  
Reaction Velocity ◽  
First Order ◽  
Kinetics Of

The kinetics of the polymerization of acetylene to cuprene on a copper catalyst between 200° and 300 °C. have been studied manometrically in a static system. The maximum velocity of the autocatalytic reaction shows a first-order dependence upon acetylene pressure. The reaction is retarded in the presence of small amounts of oxygen but accelerated by preoxidation of the catalyst. The apparent activation energy, of about 10 kcal. per mole for cuprene growth between 210° and 280 °C., changes to about 40 kcal. per mole above 280 °C. at which temperature a second reaction seems to set in. Hydrogen, carbon monoxide, or nitric oxide has no effect on the reaction velocity. Series of five successive seedings have been obtained with cuprene originally grown on cuprite, and show an effect of aging of the cuprene.

scholarly journals Microwave-Assisted Transesterification of Kusum Oil: Parametric, Kinetic and Thermodynamic Studies

2020 ◽  
Vol 32 (11) ◽  
pp. 2893-2903
Author(s):  
SHEETAL N. NAYAK ◽  
MILAP G. NAYAK ◽  
CHANDRAKANT P. BHASIN
Keyword(s):  
Activation Energy ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Molar Ratio ◽  
Pseudo First Order Reaction ◽  
Time Intervals ◽  
First Order ◽  
Microwave Assisted ◽  
Lower Heat ◽  
Kinetic And Thermodynamic Studies

Microwave-assisted transesterification of non-edible oil to produce biodiesel is gaining attention due to lower heat loss as well as rapid conversion. In this study, esterified kusum oil as a feedstock was transesterified in the presence of Ba(OH)2. At 800 W microwave power and constant magnetic stirring the effect of important process parameters such as solvent methanol molar ratio, Ba(OH)2, temperature, and time on biodiesel yield were evaluated. The parametric study suggested that 9:1 M methanol, 65 ºC reaction temperature, 2.5 wt% Ba(OH)2 catalyst and 3.5 min of transesterification time gave close to 96% biodiesel yield. At the above conditions of methanol and catalyst, the reaction kinetics and thermodynamic study were performed using different time intervals. The microwave-assisted transesterification followed pseudo-first-order reaction rate with 34.57 kJ/mol K activation energy and 205664 min-1 frequency factor. The reduction in activation energy and increase in the frequency factor reveal the non-thermal effect associated with microwave heating. The thermodynamic properties evaluated using the Eyring equation suggests non-spontaneity and endothermic nature of transesterification.

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