CFD study of the reactive gas-solid hydrodynamics in a large-scale catalytic methanol-to-olefin fluidized bed reactor. (15th March 2022)

• Record Type: Journal Article
• Authors: Wan, Zhanghao; Yang, Shiliang; Hu, Jianhang; Bao, Guirong; Wang, Hua
• Is Part Of: Energy. Volume 243(2022)
• Publication Date: 2022-03-15
• Subjects: Methanol-to-olefin -- Fluidized bed -- Heat transfer coefficient -- Particle dispersion -- Optimization; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2021.122974
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Lacking the understanding of multiphase flow in the fluidized bed methanol-to-olefin (MTO) process hinders the reactor design, operation, and optimization. Accordingly, a three-dimensional multiphase particle-in-cell model is established to study hydrodynamics and thermochemical characteristics during the MTO process in a fluidized bed reactor. After model validation, the influences of several critical operating parameters on reactor performance are discussed. The results show that particles in the medium part and freeboard of the reactor have heterogeneous velocity, temperature, and heat transfer coefficient (HTC) distributions. Thermal quantities of gas and solid phases are uniformly distributed in the medium part and freeboard of the reactor. The particle-averaged HTC under ranges from 60 to 120 W/(m 2 ·K). Increasing wall temperature enlarges the particle HTC due to the enhanced exothermic reactions. Decreasing the particle diameter gives rise to a larger particle HTC. The vertical particle dispersion coefficient ( D z ) is in the range of 0.01 m 2 /s to 0.03 m 2 /s. Methanol converts into olefin in a short period. Increasing methanol to catalyst ratio and wall temperature increases olefin including C2 H4, C3 H6, C4 H8, and C5 H10, and promotes the gas thermal properties. Particles with multi-sizes show a better MTO conversion performance than those with mono-sizes regarding the particle HTC and gas products. Graphical abstract: Image 1 Highlights: Methanol-to-olefin process in a large-scale fluidized simulated. First report of the heat transfer coefficient and dispersion coefficient of catalyst. Heat transfer coefficient increases with bed temperature but reduces with particle diameter. Olefins concentration increases with enlarging the methanol to catalyst ratio. Catalysts with multi-size enhance the methanol conversion performance.