An advanced reaction model determination methodology in solid-state kinetics based on Arrhenius parameters variation

Shahcheraghi, Seyed Hadi; Khayati, Gholam Reza; Ranjbar, Mohammad

doi:10.1007/s10973-016-5473-z

Cited by 19 publications

(14 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Various methods have been proposed over the last few years to estimate the reaction model. The detailed explanation of these different methods can be found elsewhere . In this research work, a recently developed regression method was used .…”

Section: Theoreticalmentioning

confidence: 99%

See 1 more Smart Citation

Investigation on the Thermal Degradation Kinetics of Polypropylene/Organically Modified Montmorillonite Nanocomposites with Different Levels of Compatibilizer

Vimalathithan

Barile

Casavola

et al. 2018

Macro Materials & Eng

View full text Add to dashboard Cite

Polypropylene/organically modified montmorillonite (OMMT) nanocomposites are prepared with different levels of compatibilizer (maleic anhydride functionalized polypropylene) and OMMT. A specially designed polymer nanocomposite injection molding compounder with a hyperbolic nozzle is used to prepare the nanocomposites. The thermal kinetic parameters, the activation energy, pre‐exponential factor, and the reaction model are estimated using isoconversional methods. The activation energy of virgin polypropylene is slightly higher than the polypropylene/OMMT nanocomposites. However, the presence of the compatibilizer is the vital reason for the lower activation energy in the polypropylene/OMMT nanocomposites. The reaction model explains the complexity of the reaction in the presence of OMMT and its influence on the accelerated charring in the later stages of degradation. The optimum working temperature of the prepared polypropylene/clay nanocomposites is significantly higher thus proving that OMMT improves the thermal stability of the nanocomposites. The polypropylene with 5% OMMT and 10% compatibilizer in its weight proportion has the optimum working temperature of 198 °C for 20 000 h before losing its integrity.

show abstract

Section: Theoreticalmentioning

confidence: 99%

“…The detailed explanation of these different methods can be found elsewhere. [29][30][31][32][33] In this research work, a recently developed regression method was used. [27] The method utilizes the Šesták-Berggren (SB) equation to develop Equation (10).…”

Section: Reaction Modelmentioning

confidence: 99%

Investigation on the Thermal Degradation Kinetics of Polypropylene/Organically Modified Montmorillonite Nanocomposites with Different Levels of Compatibilizer

Vimalathithan

Barile

Casavola

et al. 2018

Macro Materials & Eng

View full text Add to dashboard Cite

show abstract

“…The kinetic analysis of solid-state material in thermal decomposition can be expressed as Eq. (1) [13,[15][16][17] …”

Section: Kinetic Studiesmentioning

confidence: 99%

Investigation of the thermal decomposition kinetics of bezafibrate

Shen

Zhou

2016

J Therm Anal Calorim

View full text Add to dashboard Cite

The thermal decomposition kinetics of bezafibrate in a nitrogen atmosphere has been investigated by analyzer DTG-60. The thermal behavior of bezafibrate at the different heating rates 4, 8, 12, 16 and 20°C min -1 displays two-stage decomposition processes among 500-650 K. The activation energy (E) and pre-exponential factor (A) were calculated to be 128.72 kJ mol -1 and 3.56 9 10 10 min -1 by Flynn-Wall-Ozawa, KissingerAkahira-Sunose, Doyle, Kissinger and Šatava-Š esták methods for the second-stage decomposition process. The results show that the non-isothermal thermal decomposition mechanism of bezafibrate is classified as three-dimensional diffusion model, and the integral and differential equations are gðaÞ ¼ ½1 À ð1 À aÞ 1=3 2 and f ðaÞ ¼ 3 2 1 À a ð Þ 2=3The enthalpy (DH = ), entropy (DS = ) and Gibbs free energy (DG = ) were calculated to be 123.74 kJ mol -1 , -91.07 J mol -1 K -1 and 178.29 kJ mol -1 , respectively.Keywords Bezafibrate Á Kinetics Á Thermal decomposition Á Thermodynamical analysisList of symbols A Pre-exponential factor (min -1 ) E Activation energy (kJ mol -1 ) G = Gibbs free energy (kJ mol -1 )Einstein vibration frequency kBoltzmann constant (1.3807 9 10 -23 J K -1 ) hPlanck constant (6.625 9 10 -34 J s) t Time (s) T Absolute temperature (K) f (a) Differential form of kinetic mechanism function g (a) Integral form of kinetic mechanism functionGreek symbols a Conversion degree b Heating rate (K min -1 )

show abstract

“…Determining the Reaction Model. Shahcheraghi et al 39 proposed a method to determine reaction model from Arrhenius parameters obtained by isoconversional methods. In this method, change of the reaction rate with change of conversion or d(dα/dt)/dα is evaluated by differentiating eq 2.…”

mentioning

confidence: 99%

“…Results are shown in Figure 5. According to Figure 5, the difference between the maximum and minimum values E α in the 0.7 < α < 1 was more than 30% of the average activation energy; 39,46 therefore, this region was considered as an extra step in the reaction pathway for further investigation of its mechanism. Consequently, oxidation reactions of nano + oil were divided into four reaction regions while oxidation of crude oil was divided into the same three steps as before.…”

mentioning

confidence: 99%

Improving the Efficiency of the THAI-CAPRI Process by Nanocatalysts Originated from Rock Minerals

2018

View full text Add to dashboard Cite

Toe-to-heel air injection method is a modified pattern in situ combustion which is applicable for the recovery of heavy oil reservoirs. A fixed bed of catalyst around the production well can improve performance and quality of the produced oil; however, pilot tests revealed rapid deactivation of the catalyst bed. Dispersion of fine catalyst particles (ideally nanoparticles) around the production well by carrier fluids may reduce the deactivation problem. In the first step of this study, three nanoparticles, namely calcite, montmorillonite (MMT), and Cloisite 20A, were dispersed in a heavy oil as candidate catalysts and subjected to simultaneous thermal analysis. Kinetic parameters of different reaction zones were obtained by the Coats and Redfern model, and it was observed that 0.5 wt % of the MMT more effectively catalyzed the combustion reactions. In the second step, selected sample was subjected to multiple heating rate experiments to study detailed kinetic effects. Results were analyzed by Vyazovkin isoconversional kinetic modeling, and mechanism of different steps was determined. Results showed that all reaction regions follow nucleation–growth models. It was found that low-temperature oxidation (LTO) reactions follow a power law model (n = 1/3) which means an acceleratory nucleation process. Nanoclay did not change the reactions mechanism of both fuel deposition (FD) and high-temperature oxidation (HTO) regions (both followed A3) but E 0 and A 0 in the FD step were increased from 187.3 ± 19.0 kJ/mol and 51.2 ± 3.4 min–1 to 235.0 ± 21.8 kJ/mol and 59.7 ± 3.3 min–1, respectively. In contrast to FD, Nanoclay decreased E 0 and A 0 of HTO from 100.1 ± 17.2 kJ/mol and 34.6 ± 2.1 min–1 to 81.3.0 ± 18.5 kJ/mol and 31.0 ± 2.3 min–1, respectively. In other words, MMT intensified LTO and catalyzed FD step and consequently altered the residual coke. It also decreased energy barriers and changed mass loss pattern of HTO which could be caused by change of reactant (coke) and resistance of MMT nucleation sites to heat in contrast to ingested nucleation sites of residual coke. Altogether, MMT improved LTO and prevented formation of excessive fuel; at the same time, MMT catalyzed HTO step and caused more uniform temperature profile which could sustain combustion.

show abstract

An advanced reaction model determination methodology in solid-state kinetics based on Arrhenius parameters variation

Cited by 19 publications

References 54 publications

Investigation on the Thermal Degradation Kinetics of Polypropylene/Organically Modified Montmorillonite Nanocomposites with Different Levels of Compatibilizer

Investigation on the Thermal Degradation Kinetics of Polypropylene/Organically Modified Montmorillonite Nanocomposites with Different Levels of Compatibilizer

Investigation of the thermal decomposition kinetics of bezafibrate

Improving the Efficiency of the THAI-CAPRI Process by Nanocatalysts Originated from Rock Minerals

Contact Info

Product

Resources

About