Kinetic data, from isothermal

In order to find points of equal degrees of conversion (or equal Q-values) in Figure 2.18, van Geel [115] developed the method to evaluate kinetic data from the so-called isoconversion lines. A heat generating substance that follows Equation (2-11), when stored under isothermal conditions at different temperatures has generated an equal amount of heat (Q) when the product of t exp(-Ea/RT) has the same value. Thus, for two heat generation/time curves measured at Ti and T2, the same amount of heat (Q) has been generated, and thus the conversion is equal when ... 

Although DSC scans are relatively easy and quick in execution it is advisable to also obtain isothermal data at several different temperatures. Although the extraction of kinetic data from a single DSC scan is feasible in principle, it can be misleading if the reaction is complex. 

As a starting point for the tuning of our multi-component kinetic model we used kinetic data from closed-system non-isothermal pyrolysis experiments which describe the generation of oil and gas from a marine Type II source rock (Dieckmann et al. 1998). The frequency factors (A), activation energy ( ) distributions and hydrocarbon potentials of primary oil and gas generation of Dieckmann et al. (1998) were used as the framework for our model (Figure... 

Doyle [12] introduced a procedure for deriving kinetic data from a TG curve based on the assumption that a single non-isothermal TG curve is equivalent to a large number of comparable isothermal curves. Realizing the arbitrary nature of this assumption, the author treats the Arrhenius equation as empirical and recognizes the potential triviality of kinetic parameters derived using this relation. In the derivation equation 5.7 is rewritten in an approximate form ... 

The contents of this chapter summarize the several methodologies used to characterize the porosity of activated carbon. The isotherms of the N2 (77 K), CO2 (273 K), H2O (298 K), making use of DR and BET equations, together with a-plots, in association with enthalpies of immersion, characterize porosity in activated carbon. Equilibria data are complemented by the kinetic data from breakthrough curves. 

What is the safe storage temperature for shelf life Kinetic data Data from 1 and 2 Isothermal Storage Test... 

The techniques referred to above (Sects. 1—3) may be operated for a sample heated in a constant temperature environment or under conditions of programmed temperature change. Very similar equipment can often be used differences normally reside in the temperature control of the reactant cell. Non-isothermal measurements of mass loss are termed thermogravimetry (TG), absorption or evolution of heat is differential scanning calorimetry (DSC), and measurement of the temperature difference between the sample and an inert reference substance is termed differential thermal analysis (DTA). These techniques can be used singly [33,76,174] or in combination and may include provision for EGA. Applications of non-isothermal measurements have ranged from the rapid qualitative estimation of reaction temperature to the quantitative determination of kinetic parameters [175—177]. The evaluation of kinetic parameters from non-isothermal data is dealt with in detail in Chap. 3.6. 

Empirical grey models based on non-isothermal experiments and tendency modelling will be discussed in more detail below. Identification of gross kinetics from non-isothermal data started in the 1940-ties and was mainly applied to fast gas-phase catalytic reactions with large heat effects. Reactor models for such reactions are mathematically isomorphical with those for batch reactors commonly used in fine chemicals manufacture. Hopefully, this technique can be successfully applied for fine chemistry processes. Tendency modelling is a modern technique developed at the end of 1980-ties. It has been designed for processing the data from (semi)batch reactors, also those run under non-isothermal conditions. 

At low temperature the difference in mobility is even more striking AH = 120 Hz (247 K) for C of trans 2-butene and only 80 Hz for C2 of 1-butene (250 K). The adsorption coefficients determined from adsorption isotherms and kinetic data which are 5xlO 2 torr for 1-butene and 8.2x10 torr l for trans 2-butene (4) support entirely this difference in mobility. 

Measurement of the extent to which the adsorbent removes the adsorbate from a liquid or gaseous phase. The data is used to construct adsorption isotherms and is often fitted to a model to provide information about binding constants, adsorption maxima and other parameters, and also speciation of surface complexes. Kinetic data may also be obtained. 

Gonzalez, J. L., and Salvador, F. (1982), Kinetics of reactions in solution Method for the treatment of data from non-isothermal chemical kinetic experiments, React. Kinet. Catal. Lett., 21(1-2), 167-171. 

From the experimental kinetic data obtained by isothermal and adiabatic calorimetry, a technique for determining the kinetic and thermodynamic parameters for a somewhat simplified Scheme (8) has been developed. Table 2 presents thermodynamic parameters for two models and a real systems. 

Kinetic data, whether they are obtained classically from isothermal decompn studies or by DSC, can be used to calculate the critical temp at which any size of an expl can self-heat to expln. The heat-balance problem has been examined by Frank-Kamenetskii (Ref 1) and by Zinn and Mader (Ref 4). The resulting relationship between kinetic and geometric factors is as follows. ... 

The parameters in Eq. (2.59) are usually determined from the condition that some function mean-square deviations between the experimental and calculated curves (the error function). The search for the minimum of the function Nelder-Mead algorithm.103 As an example, Table 2.2 contains results of the calculation of the constants in a self-accelerating kinetic equation used to describe experimental data from anionic-activated e-caprolactam polymerization for different catalyst concentrations. There is good correlation between the results obtained by different methods,as can be seen from Table 2.2. In order to increase the value of the experimental results, measurements have been made at different non-isothermal regimes, in which both the initial temperature and the temperature changes with time were varied. 

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