Numerical simulation of granular silicon growth and silicon fines formation process in polysilicon fluidized bed--颗粒学报PARTICUOLOGY

Gu, G., Lv, G., Ma, W., Du, S., & Fu, B. (2024). Numerical simulation of granular silicon growth and silicon fines formation process in polysilicon fluidized bed. Particuology, 87, 74-86. https://doi.org/10.1016/j.partic.2023.07.019

Numerical simulation of granular silicon growth and silicon fines formation process in polysilicon fluidized bed

Guangkai Gu a b, Guoqiang Lv a b *, Wenhui Ma a b, Shanlin Du a b, Boqiang Fu a b

a Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China
b State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province, Kunming 650093, China

10.1016/j.partic.2023.07.019

Volume 87, April 2024, Pages 74-86

Received 22 May 2023, Revised 16 July 2023, Accepted 28 July 2023, Available online 19 August 2023, Version of Record 28 August 2023.

E-mail: lvguoqiang_ok@aliyun.com

Highlights

• Considering role of silicon fines scavenging based on phase velocity differences to study granular silicon growth processes.

• Heterogeneous deposition occurs in the bottom region.

• The dilute phase region is dominated by the silicon fines scavenging effect.

• Operating conditions affect the formation of silicon fines and growth rate.

• Exploring the selectivity of granular silicon growth.

Abstract

Operating conditions strongly affect the yield and quality of polysilicon in a polysilicon fluidized bed. In this study, a new model of polysilicon fluidized bed was established using the Euler–Euler model coupled with population balance model (PBM), which was combined with fluid flow, heat, and mass transfer models, while considering the scavenging effect of silicon fines. The effects of different operating conditions on the deposition and formation rates of silicon fines were investigated. Results show that the model can correctly describe the particle growth process in the fluidized bed of polysilicon. The silicon fines and the interphase velocity difference show “N”- and “M”-shaped distributions along the axial direction, respectively. The particle temperature and concentration near the wall are higher than those in the central region. The decomposition of silane in the bottom region of the bed is dominated by heterogeneous deposition. The scavenging of silicon fines occurs in the dilute-phase region. The effects of operating conditions, i.e. inlet gas temperature, silane composition, and gas velocity, on the reactor performance were also explored comprehensively. Increasing the inlet gas composition and velocity enhances the formation rates of solid silicon and fines. Increasing the inlet gas temperature promotes the growth of solid silicon and inhibits the formation of silicon fines. High fluidization ratio, low inlet silane concentration, and high inlet gas temperature enhance the selectivity of silicon growth.

Graphical abstract

Keywords

Polysilicon fluidized bed; Particle growth; Fines; CFD; Population balance model (PBM)

文章导读