Development of a hydrodynamic model and the corresponding virtual software for dual-loop circulating fluidized beds

Abstract

Dual-loop circulating fluidized bed (CFB) reactors have been widely applied in industry because of their good heat and mass transfer characteristics and continuous handling ability. However, the design of such reactors is notoriously difficult owing to the poor understanding of the underlying mechanisms, meaning it has been heavily based on empiricism and stepwise experiments. Modeling the gas-solid CFB system requires a quantitative description of the multiscale heterogeneity in the sub-reactors and the strong coupling between them. This article proposed a general method for modeling multi-loop CFB systems by utilizing the energy minimization multiscale (EMMS) principle. A full-loop modeling scheme was implemented by using the EMMS model and/or its extension models to compute the hydrodynamic parameters of the sub-reactors, to achieve the mass conservation and pressure balance in each circulation loop. Based on the modularization strategy, corresponding interactive simulation software was further developed to facilitate the flexible creation and fast modeling of a customized multi-loop CFB reactor. This research can be expected to provide quantitative references for the design and scale-up of gas-solid CFB reactors and lay a solid foundation for the realization of virtual process engineering.

Key words： multi-loop circulating fluidized bed; mathematical modeling; energy minimization multiscale; virtual fluidization; mesoscale structure

Acknowledgments

We would like to thank the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA07080400) and the National Natural Science Foundation of China (Grant No. U1710251) for their financial support. Many thanks to the anonymous reviewers for their constructive suggestions, which were extremely helpful in improving this article.

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