Numerical approach for modeling particle transport phenomena in a closed loop of a circulating fluidized bed--颗粒学报PARTICUOLOGY

Adamczyk, W. P., Kozołub, P., Kruczek, G., Pilorz, M., Klimanek, A., Czakiert, T., & Węcel, G. (2016). Numerical approach for modeling particle transport phenomena in a closed loop of a circulating fluidized bed. Particuology, 29, 69-79. https://doi.org/10.1016/j.partic.2015.12.006

Numerical approach for modeling particle transport phenomena in a closed loop of a circulating fluidized bed

Wojciech P. Adamczyk ^a *, Paweł Kozołub ^b, Grzegorz Kruczek ^a, Monika Pilorz ^a, Adam Klimanek ^a, Tomasz Czakiert ^c, Gabriel Węcel ^a

a Institute of Thermal Technology, Silesian University of Technology, Gliwice, Poland
b AMEC Foster Wheeler, Staszica 31, 41-200 Sosnowiec, Poland
c Institute of Advanced Energy Technologies, Częstochowa University of Technology, Częstochowa, Poland

10.1016/j.partic.2015.12.006

Volume 29, December 2016, Pages 69-79

Received 3 August 2015, Revised 9 December 2015, Accepted 11 December 2015, Available online 21 March 2016, Version of Record 18 November 2016.

E-mail: wojciech.adamczyk@polsl.pl

Highlights

• Particle transport phenomena in a pilot CFB was accurately predicted using a looping procedure.

• New calculation technique was proposed for modeling fluidization process within close loop of CFB.

• Hybrid Euler–Lagrange approach was applied for modeling particle transport within the CFB boiler.

Abstract

Numerical modeling of a large scale circulating fluidized bed (CFB) imposes many complexities and difficulties. Presence of a dense solid phase, a variety of spatial and time scales as well as complex model geometries requires advanced numerical techniques. Moreover, the appropriate selection of a numerical model capable of solving granular flow, and geometrical model simplification can have a huge impact on the predicted flow field within the CFB boiler. In order to reduce the cost of the numerical simulations, the complex CFB boiler geometry is reduced to that of the combustion chamber. However, a question arises as to how much one can simplify the geometrical model without losing accuracy of numerical simulations. To accurately predict the gas–solid and solid–solid mixing processes within subsequent sections of the CFB boiler (combustion chamber, solid separator, drain section), a complete 3D geometrical model should be used. Nevertheless, because of the presence of various spatial and temporal scales within subsequent boiler sections, the complete model of the 3D CFB boiler is practically unrealizable in numerical simulations. To resolve the aforementioned problems, this paper describes a new approach that can be applied for complete boiler modeling. The proposed approach enables complex particle transport and gas flow problems within each of the boiler sections to be accurately resolved. It has been achieved by dividing the CFB boiler geometry into several submodels, where different numerical approaches can be used to resolve gas–solid transport. The interactions between computational domains were taken into account by connecting the inlets/outlets of each section using a set of user-defined functions implemented into the solution procedure. The proposed approach ensures stable and accurate solution within the separated boiler zones.

Graphical abstract

Keywords

Fluidization; CFB; Numerical modeling; Multiphase flow; Particle transport; Cyclone

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