Numerical simulation of uranium tetrafluoride fluorination in a multistage spouted bed using the improved CFD-DEM chemical reaction model (Open Access)--颗粒学报PARTICUOLOGY

Qiu, M., Chen, Z., Jiang, L., Liu, R., Tang, Y., & Liu, M. (2023). Numerical simulation of uranium tetrafluoride fluorination in a multistage spouted bed using the improved CFD-DEM chemical reaction model. Particuology, 75, 119-136. https://doi.org/10.1016/j.partic.2022.07.010

Numerical simulation of uranium tetrafluoride fluorination in a multistage spouted bed using the improved CFD-DEM chemical reaction model (Open Access)

Mofan Qiu, Zhao Chen, Lin Jiang, Rongzhen Liu, Yaping Tang, Malin Liu ^*

Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Tsinghua University, Beijing, 100084, China

10.1016/j.partic.2022.07.010

Volume 75, April 2023, Pages 119-136

Received 14 May 2022, Revised 3 July 2022, Accepted 21 July 2022, Available online 8 August 2022, Version of Record 18 August 2022.

E-mail: liumalin@tsinghua.edu.cn

Highlights

• Coupling model based on CFD-DEM was established to simulate UF₄ fluoridation.

• Discretized particle shrinking model was proposed and validated.

• Multistage conical fluidized bed was designed to extended the application range.

• Effects of operating parameters related to industrial production were discussed.

Abstract

A CFD-DEM reaction coupling model was established to simulate UF₄ fluorination process, in which heat and mass transfer, heterogeneous chemical reaction, and particle shrinkage model were considered. The gas behavior was described by the conservation laws of mass, momentum, and energy. The solid phase is modeled with the discrete element method, considering the gas–solid interphase force, contact force, heat transfer, and chemical reaction models based on the discretized surface. Each particle can be individually tracked and associated with specific physical properties. The proposed CFD-DEM reaction coupling model based on particle shrinking reaction model with discretized surface was validated by the experimental and literature results at first. Then a multistage conical spouted bed was proposed and the process of UF₄ fluoridation reaction in it was investigated. The fluidization characteristics and the concentration distribution of gaseous products in the spouted bed with an extended gas velocity range were obtained and analyzed. In addition, the effects of different parameters, such as superficial gas velocity, temperature, fluorine concentration, on fluoridation rate and the fluorine conversion rate were investigated based on the proposed CFD-DEM reaction coupling model. The results obtained in this work are beneficial for method development of the chemical reaction simulation research in particle scale using the CFD-DEM model, and useful for operation and equipment parameters design of the uranium tetrafluoride fluorinate industrial process in the future.

Graphical abstract

Keywords

CFD-DEM; Particle shrinkage model; Multistage spouted bed; Uranium fluorination

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