Are nonisothermal kinetics fearing historical Newton’s cooling law, or are just afraid of inbuilt complications due to undesirable thermal inertia?

Šesták, Jaroslav

doi:10.1007/s10973-018-7705-x

Cited by 13 publications

(13 citation statements)

References 75 publications

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“…Thus, it can be concluded that the predicted solution converges if the mathematical model involves the nonlinear thermal profile. The results obtained for pine needles are compared with similar kind of coniferous species, and it has been found that activation energy is within the range of activation energy derived from other statistical models [14,[68][69][70][71][72][73].…”

Section: Resultsmentioning

confidence: 70%

The generalisation of a multi-reaction model for polynomial ramping of temperature

Dhaundiyal

Singh

2020

J Therm Anal Calorim

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This paper deals with the numerical solution of a multi-reaction model for the complex thermal history. The effect of thermal and kinetic parameters is investigated in this analytical study. The concept of moving maximum with time and the approximation of complex integral form of reactivity are introduced with the help of an advance integral methodology. The sigmoidal reactions of biomass pyrolysis are explained through the transmuted density function. Thermogravimetry of biomass sample is performed with the help of thermogravimetric analyser at different heating rates (5 °C min −1 , 10 °C min −1 and 15 °C min −1 ). The solutions of the integral form are obtained at different degrees of the nonlinear equation and to generalise the proposed methodology for the industrial application. The main objective of the paper is to identify the correlation of temperature history with the kinetics of biomass pyrolysis.

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Section: Resultsmentioning

confidence: 70%

The generalisation of a multi-reaction model for polynomial ramping of temperature

Dhaundiyal

Singh

2020

J Therm Anal Calorim

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“…Some kineticists are reasoning that its incorporation would be too complicated and would impair the computational throughput. Others say that if thermal inertia has not been applied in kinetics over the past 300 years, there is no reason to apply it now and in the future . Still others use philosophical resignation, saying that science is never accurate and it only approximates the truth—as an excuse for knowingly using inaccurate models while the ways to correct them has been known for a long time…”

Section: Discussionmentioning

confidence: 99%

“…Others say that if thermal inertia has not been applied in kinetics over the past 300 years, there is no reason to apply it now and in the future. 45 Still others use philosophical resignation, saying that science is never accurate and it only approximates the truth 46 -as an excuse for knowingly using inaccurate models 16 while the ways to correct them has been known for a long time Therefore, the published values of activation energy 5-9 may not be authoritative, 46 as they may be off by as much as several tens of percent. 21 It is worthy of note that the relative (per gram) value of thermal inertia is the same for large and small samples.…”

Section: Discussionmentioning

confidence: 99%

Ignoring heat inertia impairs accuracy of determination of activation energy in thermal analysis

Šesták

2018

Int J of Chemical Kinetics

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This paper critically analyzes the traditional method of kinetic determination of activation energy by sectioning the recorded differential thermal analysis peak area. This procedure is incorrect because it misses the impact of thermal inertia, which changes the shape of the peak's base line from straight to s‐shape. This effect has been known since the Newton cooling law, but the resulting errors persist to be interwoven into all the kinetic methods based on nonisothermal thermoanalytical measurements. Relating to calorimetry, it is necessary here because heat inertia has become a standard part of heat determination via using the Tian historical equation. The role and impact of heat inertia is discussed and analyzed in detail.

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“…It reveals that the effect of thermal inertia is due to thermally forced change of motional inertia of inherent particles (atoms, molecules), which is often overlooked, even though these effects have been the basis of the theoretical work of greats in the history of heat analysis. 3,[8][9][10][11][12][13] While no one would question the validity of mechanical momentum, heat inertia has remained forgotten and it continues to be neglected in the sphere of thermoanalytical kinetics.…”

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confidence: 99%

“…17-19, was not sufficiently considerate to take into account the physical phenomena associated with the heat transfer dynamics. [10][11][12][13][14][15][16] This phenomenon is included in the basic heat balance equations describing thermoanalytical experiments, especially those associated with the determination of thermal differences. It appears in all early theories from the classical Tian's equation, 20 for long known in calorimetry, 21,22 through the works on DTA theory [23][24][25] until a more recent specifications 26,27 where the always presented term C p (dΔT/dt) is considered as heat inertia.…”

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confidence: 99%

The evaluation of nonisothermal thermoanalytical kinetics is simplified without the description of heat transfers, such as thermal inertia, which is not negligible, as indicated by Vyazovkin

Šesták

2021

Int J of Chemical Kinetics

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In the field of thermoanalytical kinetics, which is widely used, basic questions arise regarding a possible description of the effect of heat transfer and subsequent thermal inertia. Current practice still uses a simplified interpretation of directly measured data for an inert sample at a constant temperature rise to describe the studied reaction, which leads to a simplified reaction conversion ratio, which is further used for various mathematical processing. The analysis of the introduced rectangular heat pulses and their indication by DTA clearly shows that the effect of thermal inertia is fundamental and not negligible. This is, after all, known from calorimetry, where the integral constant of inertia has historically been used to calibrate the descending temperature, but it cannot generally be applied to the whole temperature process due to its nonlinearity. In the case of parallel processing, for example by gradually increasing the heating rate, the effect of thermal inertia can be partially compensated for each other which have yet to be confirmed. However, for the kinetic analysis of a single peak, it is necessary to adapt to the effect of the thermal delay due to thermal inertia, which, similarly to the measured enthalpy, is tied to the sample size. Of course, it will be up to the researcher to find a solution that also includes the effect of heat transfer and dissipation, which should become the main principle of thermoanalytical methods of the future, as shown by current examples combining thermal processes with their specific kinetics.

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Are nonisothermal kinetics fearing historical Newton’s cooling law, or are just afraid of inbuilt complications due to undesirable thermal inertia?

Cited by 13 publications

References 75 publications

The generalisation of a multi-reaction model for polynomial ramping of temperature

The generalisation of a multi-reaction model for polynomial ramping of temperature

Ignoring heat inertia impairs accuracy of determination of activation energy in thermal analysis

The evaluation of nonisothermal thermoanalytical kinetics is simplified without the description of heat transfers, such as thermal inertia, which is not negligible, as indicated by Vyazovkin

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