Thermogravimetric Analysis of Tobacco Combustion Assuming DAEM Devolatilization and Empirical Char-Burnoff Kinetics

Várhegyi, Gábor; Czégény, Zsuzsanna; Liu, Chuan; McAdam, Kevin

doi:10.1021/ie901180d

Cited by 29 publications

(32 citation statements)

References 35 publications

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“…24 Among others, the antecedents of the present work also used it. 17,20,21 However, the magnitude differences were very high in the present work. was used for the CRR experiments which is ca.…”

Section: Sample Characterization and Preparationcontrasting

confidence: 62%

Kinetic Behavior of Torrefied Biomass in an Oxidative Environment

et al. 2013

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ABSTRACT. The combustion of four torrefied wood samples and their feedstocks (birch and spruce) was studied at slow heating programs, under well-defined conditions by thermogravimetry (TGA). Particularly low sample masses were employed to avoid the self-heating of the samples due to the huge reaction heat of the combustion. Linear, modulated and constant-reaction rate (CRR) temperature programs were employed in the TGA experiments in gas flows of 5 and 20% O2. In 2 this way the kinetics was based on a wide range of experimental conditions. The ratio of the highest and lowest peak maxima was around 50 in the experiments used for the kinetic evaluation.A recent kinetic model of Várhegyi et al. [Energy & Fuels 2012, 26, 1323-1335 was employed with modifications. This model consists of two devolatilization reactions and a successive char burn-off reaction. The cellulose decomposition in the presence of oxygen has a self-accelerating (autocatalytic) kinetics. The decomposition of the non-cellulosic parts of the biomass was described by a distributed activation model. The char burn-off was approximated by power-law (n-order) kinetics. Each of these reactions has its own dependence on the oxygen concentration that was expressed by power-law kinetics, too. The complexity of the applied model reflects the complexity of the studied materials. The model contained 15 unknown parameters for a given biomass. Part of these parameters could be assumed common for the six samples without a substantial worsening of the fit quality. This approach increased the average experimental information for an unknown parameter by a factor of 2 and revealed the similarities in the behavior of the different samples.

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Section: Sample Characterization and Preparationcontrasting

confidence: 62%

Kinetic Behavior of Torrefied Biomass in an Oxidative Environment

et al. 2013

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“…The employed numerical methods have been described in details earlier. 18,26,27 The kinetic evaluation was based on the least squares evaluation of the -dm/dt curves. The method 28 …”

Section: Numerical Methods Fortran 95 and C++programs Were Employed mentioning

confidence: 99%

Kinetics of Corncob Pyrolysis

et al. 2012

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ABSTRACT. Two different corncob samples from different continents and climates were studied by thermogravimetry at linear and nonlinear heating programs in inert gas flow. A distributed activation energy model (DAEM) with three and four pools of reactants (pseudocomponents) was used due to the complexity of the biomass samples of agricultural origin. The resulting models described well the experimental data. When the evaluation was based on a smaller number of experiments, similar model parameters were obtained which were suitable for predicting experiments at higher heating rates. This test indicates that the available experimental information was sufficient for the determination of the model parameters. The checks on the prediction capabilities were considered to be an essential part of the model verification. In another test the experiments of the two samples were evaluated together, 2 assuming more or less common kinetic parameters for both cobs. This test revealed that the reactivity differences between the two samples are due to the differences in their hemicelluloses and extractives.The kinetic parameter values from a similar earlier work on other biomasses (Várhegyi, G.; Bobály, B.; Jakab, E.; Chen, H. Energy Fuels, 2011, 25, 24-32.) could also been used, indicating the possibilities of a common kinetic model for the pyrolysis of a wide range of agricultural by-products.

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“…20 Later this type of research was extended to a wider range of biomasses and materials derived from plants, including several studies on tobacco devolatilization. [21][22][23][24][25][26][27][28][29][30][31][32] Despite the complicated mathematics of this type of modeling, the works based on DAEM kinetics have frequently employed more than one parallel reaction. The resolution of the overlapping curves by parallel DAEM reactions and the finding of a good fit were achieved by a trial-and-error parametersearch in several studies.…”

Section: Introductionmentioning

confidence: 99%

“…10% change in E0 can be well compensated by a proper change of the corresponding distribution width and pre-exponential factor. 31 Várhegyi et al 23,[31][32] and Becidan et al 29 based DAEM kinetic studies on the simultaneous evaluation of experiments with linear and stepwise temperature programs. This method served to increase the available experimental information, as outlined elsewhere.…”

Section: Introductionmentioning

confidence: 99%

Thermogravimetric Study of Biomass Pyrolysis Kinetics. A Distributed Activation Energy Model with Prediction Tests

et al. 2010

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ABSTRACT. The pyrolysis of four biomasses (corn stalk, rice husk, sorghum straw and wheat straw) was studied at different temperature -time functions in inert gas flow by thermogravimetric analysis (TGA). Linear and stepwise heating programs were employed. A distributed activation energy model (DAEM) with three pools of reactant (three pseudocomponents) was used due to the complexity of the biomass samples of agricultural origin. Compensation effects were observed between the kinetic parameters similarly to the works of other investigators. The compensation effects result in ambiguous parameter values hence they were eliminated by decreasing the number of the unknown parameters. For this purpose part of the kinetic parameters was assumed to be the same for the four biomasses. This approach also helps to express the similarities of the samples in the model. The sixteen experiments were evaluated simultaneously by the method of least squares to obtain dependable kinetic parameters. 2The resulting models described well the experimental data and were suitable for predicting experiments at higher heating rates. The checks on the prediction capabilities were considered to be an essential part of the model verification.

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Thermogravimetric Analysis of Tobacco Combustion Assuming DAEM Devolatilization and Empirical Char-Burnoff Kinetics

Cited by 29 publications

References 35 publications

Kinetic Behavior of Torrefied Biomass in an Oxidative Environment

Kinetic Behavior of Torrefied Biomass in an Oxidative Environment

Kinetics of Corncob Pyrolysis

Thermogravimetric Study of Biomass Pyrolysis Kinetics. A Distributed Activation Energy Model with Prediction Tests

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