Components, formulations, solutions, evaluation, and application of comprehensive combustion models

Eaton, A.M.; Smoot, L.D.; Hill, Scott C.; Eatough, C.N.

doi:10.1016/s0360-1285(99)00008-8

Cited by 235 publications

(110 citation statements)

References 142 publications

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“…15 The present work deals with the devolatilization and successive char-burn-off that occur in overlapping time/temperature intervals. Four model variations were tested by determining the model parameters and verifying the models on large series of experiments using the method of least squares.…”

Section: Introductionmentioning

confidence: 99%

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

Várhegyi

Czégény

Liu³

et al. 2009

Ind. Eng. Chem. Res.

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ABSTRACT. Two blends of tobacco (Virginia and Burley) were studied by thermogravimetry at linear and nonlinear heating programs in gas flows containing 2, 4 and 9% oxygen. A kinetic scheme of successive devolatilization and char burn-off reactions was assumed. A distributed activation energy model was assumed for the devolatilization with a Gaussian distribution and a constant pre-exponential factor. The evaluations were also carried out using non-constant pre-exponential factors that depended on the activation energy. The char burn-off was described by first order kinetics and by an empirical model that took into account the change of the reactivity with the conversion of the sample. The dependence of the rate of combustion on the oxygen concentration was approximated by a power function. Series of 15 and 30 experiments were used for the determination of the model parameters by simultaneous least squares evaluation of the experiments. The considerations, methods and results can also be used in the field of biomass gasification and combustion.

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Section: Introductionmentioning

confidence: 99%

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

Várhegyi

Czégény

Liu³

et al. 2009

Ind. Eng. Chem. Res.

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“…In order to tackle this problem, comprehensive models have been used to represent boiler operation as shown in Eaton et al (1999). Following this lead, the present study also developed numerical simulations of the grate sugarcane bagasse boiler using a comprehensive CFD model.…”

Section: Methodsmentioning

confidence: 99%

“…Among many strategies applied to model heterogeneous combustion of solid fuels such as coal or biomass, one promising technique involves the use of comprehensive models. The works of Hill and Smoot (1993), Smoot (1997) and Eaton et al (1999) discuss the definitions and develop some important comprehensive models. The comprehensive model approach allows the selection of specific physical processes coupled with mass, momentum and/or energy conservation equations.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Radiation in the Gas Combustion Model for Sugarcane Bagasse Grate Boiler

Ferreira

Arnao

Moreira

et al. 2016

Braz. J. Chem. Eng.

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-This work evaluates the impact of different radiation models on the results of Computational Fluid Dynamics (CFD) simulation of a sugarcane bagasse grate boiler. CFD has been applied extensively in the development of comprehensive models for biomass heterogeneous combustion. The model presented in this paper considers the turbulent flow represented by the standard k-ε model and the homogeneous combustion of the volatiles CH4 and CO by the Eddy Dissipation Model (EDM). Thermal profiles have been evaluated by comparing the results obtained without radiation with the results obtained with radiation represented by the P1 Approximation Method and by the Discrete Transfer Method (DTM). The discussion of the flue gas temperature and chemical composition profiles provides useful information regarding the characteristics of the internal flow and of the equipment operating conditions.

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“…Up to now very few works can be found about the kinetic scheme of the reaction in the gas phase or between two different phases in multi-fluid simulations. Eaton et al (1999) [9] detailed the numerical approach for the study of reactive multiphase flows, especially for coal pyrolysis. Konan et al [10] performed numerical simulations of a reactive fluidized bed with a N-phase CFD code in the framework of uranium fluorination.…”

Section: Introductionmentioning

confidence: 99%

Multiscale Study of Reactive Dense Fluidized Bed for FCC Regenerator

Moula

Nastoll²,

Simonin³

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Re´sume´-É tude multi-e´chelle d'un lit fluidise´dense re´actif de type re´ge´ne´rateur FCC -Ce travail porte sur les e´coulements re´actifs gaz-particules tels que ceux que l'on rencontre dans la combustion du coke pour la re´ge´ne´ration des particules de catalyseurs de FCC. Les e´tudes re´alise´es pour de tels e´coulements montrent qu'en ge´ne´ral le taux de re´action global au cours du temps est mal pre´dit. La raison peut eˆtre lie´e a`la cine´tique chimique utilise´e qui est en ge´ne´ral base´e sur des expe´riences macroscopiques. Le lien entre des releve´s macroscopiques et une cine´tique chimique de re´action he´te´roge`ne locale qui a lieu a`l'interface meˆme entre la surface de la particule et le gaz environnant n'est pas imme´diat. Nous avons utilise´des re´sultats cine´tiques issus d'expe´riences afin d'identifier les proble`mes qui apparaissent lorsque l'on utilise cette meˆme cine´tique pour des e´chelles diffe´rentes. Une analyse multi-e´chelle est donc effectue´e. Nous montrons alors que la fraction volumique de particules a une influence sur le taux de re´action. Par ailleurs, nous montrons la ne´cessite´de de´velopper un mode`le de sous-maille pour le taux de re´action lie´a`la pre´sence de clustering dans les e´coulements gazparticules. Dans les calculs effectue´s couramment, le taux de re´action est calcule´en conside´rant une re´partition homoge`ne des particules a`l'inte´rieur de la maille de calcul. En effet l'analyse microscopique montre que lorsque les particules sont regroupe´es en nuages denses, la fraction massique de dioxyge`ne a`l'inte´rieur de ce nuage est rapidement nulle et donc le dioxyge`ne est en de´faut. La re´action he´te´roge`ne est donc limite´e.Abstract -Multiscale Study of Reactive Dense Fluidized Bed for FCC Regenerator -This study deals with reactive gas particle flows like the coke combustion during the regeneration of FCC particles. In this kind of reactive flow, the global reaction rate is usually bad predicted. In a first approximation, the chemical scheme can be the reason because of the limitation of its modeling. It is usually based on macroscopic experimental results. The link between these macroscopic measurements and a local kinetics of the heterogeneous reaction occuring at the gas-particle interface is not confirmed. Results of kinetics coming from experimental measurements are used and we try to highlight the problems that appear when the same kinetics are used at different scales. In common industrial computations, coarse meshes are used to solve continuity equations. Averaged or filtered Navier-Stokes and species continuity equations have to be solved in which additional correlation terms appear because of non-linear terms in the original equations, including reaction rate correlation. Therefore a multiscale analysis is performed in order to improve the modeling of this terms. This paper, shows that the eulerian formulation of kinetics has to be improved due to the impact Oil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 68 (2013), No. ...

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Components, formulations, solutions, evaluation, and application of comprehensive combustion models

Cited by 235 publications

References 142 publications

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

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

The Impact of Radiation in the Gas Combustion Model for Sugarcane Bagasse Grate Boiler

Multiscale Study of Reactive Dense Fluidized Bed for FCC Regenerator

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