Particle size distribution in CPFD modeling of gas–solid flows in a CFB riser--颗粒学报PARTICUOLOGY

Wang, Q., Niemi, T., Peltola, J., Kallio, S., Yang, H., Lu, J., & Wei, L. (2015). Particle size distribution in CPFD modeling of gas–solid flows in a CFB riser. Particuology, 21, 107-117. https://doi.org/10.1016/j.partic.2014.06.009

Particle size distribution in CPFD modeling of gas–solid flows in a CFB riser

Qinggong Wang ^a, Timo Niemi ^b, Juho Peltola ^b, Sirpa Kallio ^b, Hairui Yang ^a, Junfu Lu ^a *, Lubin Wei ^c

a Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China
b VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Finland
c School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083, China

10.1016/j.partic.2014.06.009

Volume 21, August 2015, Pages 107-117

Received 2 December 2013, Revised 18 June 2014, Accepted 24 June 2014, Available online 6 November 2014, Version of Record 6 June 2015.

E-mail: lvjf@mail.tsinghua.edu.cn

Highlights

• Effect of particle size distribution in CPFD modeling was investigated.

• Solids with both binary and polydisperse PSD were considered in the simulations.

• The CPFD simulation results were evaluated by comparing with experiments and Eulerian simulations.

• Distributions of particle concentration and velocity were well predicted.

• CPFD required less computational resources compared with other models.

Abstract

A computational particle fluid dynamics (CPFD) numerical method to model gas–solid flows in a circulating fluidized bed (CFB) riser was used to assess the effects of particle size distribution (PSD) on solids distribution and flow. We investigated a binary PSD and a polydisperse PSD case. Our simulations were compared with measured solids concentrations and velocity profiles from experiments, as well as with a published Eulerian-Eulerian simulation. Overall flow patterns were similar for both simulation cases, as confirmed by experimental measurements. However, our fine-mesh CPFD simulations failed to predict a dense bottom region in the riser, as seen in other numerical studies. Above this bottom region, distributions of particle volume fraction and particle vertical velocity were consistent with our experiments, and the simulated average particle diameter decreased as a power function with riser height. Interactions between particles and walls also were successfully modeled, with accurate predictions for the lateral profiles of particle vertical velocity. It was easy to implement PSD into the CPFD numerical model, and it required fewer computational resources compared with other models, especially when particles with a polydisperse PSD were present in the heterogeneous flow.

Graphical abstract

Keywords

Circulating fluidized bed riser; Particle size distribution; CPFD; Numerical simulation

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