Modeling of particle transport and combustion phenomena in a large-scale circulating fluidized bed boiler using a hybrid Euler

Adamczyk, W. P., Węcel, G., Klajny, M., Kozołub, P., Klimanek, A., & Białecki, R. A. (2014). Modeling of particle transport and combustion phenomena in a large-scale circulating fluidized bed boiler using a hybrid Euler–Lagrange approach. Particuology, 16, 29–40. https://doi.org/10.1016/j.partic.2013.10.007

Modeling of particle transport and combustion phenomena in a large-scale circulating fluidized bed boiler using a hybrid Euler–Lagrange approach

Wojciech P. Adamczyk ^a *, Gabriel Węcel ^a, Marcin Klajny ^b, Paweł Kozołub ^a, Adam Klimanek ^a, Ryszard A. Białecki ^a

a Institute of Thermal Technology, Silesian University of Technology, Konarskiego 22, 44-100 Gliwice, Poland
b Foster Wheeler Energia Polska Sp. z o.o., Staszica 31, 41-200 Sosnowiec, Poland

10.1016/j.partic.2013.10.007

Volume 16, October 2014, Pages 29-40

Received 28 April 2013, Revised 27 August 2013, Accepted 9 October 2013, Available online 15 January 2014.

E-mail: wojciech.adamczyk@polsl.pl

Highlights

• Application of a hybrid Euler–Lagrange approach for a large scale CFB facility was shown.

• Air-fuel combustion process was modeled for a large scale industrial CFB boiler.

• Numerical simulation results were validated against experimentally measured data.

Abstract

The constantly developing fluidized combustion technology has become competitive with a conventional pulverized coal (PC) combustion. Circulating fluidized bed (CFB) boilers can be a good alternative to PC boilers due to their robustness and lower sensitivity to the fuel quality. However, appropriate engineering tools that can be used to model and optimize the construction and operating parameters of a CFB boiler still require development. This paper presents the application of a relatively novel hybrid Euler–Lagrange approach to model the dense gas–solid flow combined with a combustion process in a large-scale industrial CFB boiler. In this work, this complex flow has been resolved by applying the ANSYS FLUENT 14.0 commercial computational fluid dynamics (CFD) code. To accurately resolve the multiphase flow, the original CFD code has been extended by additional user-defined functions. These functions were used to control the boiler mass load, particle recirculation process (simplified boiler geometry), and interphase hydrodynamic properties. This work was split into two parts. In the first part, which is referred to as pseudo combustion, the combustion process was not directly simulated. Instead, the effect of the chemical reactions was simulated by modifying the density of the continuous phase so that it corresponded to the mean temperature and composition of the flue gases. In this stage, the particle transport was simulated using the standard Euler–Euler and novel hybrid Euler–Lagrange approaches. The obtained results were compared against measured data, and both models were compared to each other. In the second part, the numerical model was enhanced by including the chemistry and physics of combustion. To the best of the authors’ knowledge, the use of the hybrid Euler–Lagrange approach to model combustion is a new engineering application of this model. In this work, the combustion process was modeled for air-fuel combustion. The simulation results were compared with experimental data. The performed numerical simulations showed the applicability of the hybrid dense discrete phase model approach to model the combustion process in large-scale industrial CFB boilers.

Graphical abstract

Keywords

CFB; Fluidization; Combustion; Particles; Large boiler; CFD

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