Abstract In this work, population balance model (PBM) that describes particle size distribution (PSD) and liquid vaporization modeling scheme (VMS) (including the heat transfer model and droplet vaporization model), which describes liquid evaporation, were incorporated into a three-fluid computational fluid dynamics (CFD) model to analyze PSD behavior in an industrial–scale gas–liquid–solid three–phase polyethylene fluidized bed reactor (FBR). The validation of this CFD–VMS–PBM coupled model was conducted through comparing results with industrial and calculated data, which then was applied to discuss the characteristics of PSD behavior in terms of the effects of particle kinetics, node number, and condensed liquid content. Unlike gas–solid polyethylene conventional FBRs, although the PSD behavior was dominated by particle agglomeration, particle breakage kinetics exerted a great impact on PSD, especially at the initial polymerization period when it competed with aggregates to decrease the defluidization risk of the reactor. Furthermore, the number of nodes strongly affected PSD simulation results, and using three nodes was the best configuration. In this three–phase system, the increase in the condensed liquid content improved the particle growth rate, which affected the reactor's productivity and product's properties, such as mean particle size and final PSD.

中文翻译：

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气-液-固聚乙烯流化床反应器粒度分布行为建模与模拟

摘要 在这项工作中，描述粒度分布 (PSD) 的总体平衡模型 (PBM) 和描述液体蒸发的液体汽化建模方案 (VMS)（包括传热模型和液滴汽化模型）被合并到一个三流体计算流体动力学 (CFD) 模型用于分析工业规模气-液-固三相聚乙烯流化床反应器 (FBR) 中的 PSD 行为。通过将结果与工业数据和计算数据进行比较，对该 CFD-VMS-PBM 耦合模型进行了验证，然后将其应用于讨论粒子动力学、节点数和冷凝液体含量影响方面的 PSD 行为特征。与气固聚乙烯常规 FBR 不同，尽管 PSD 行为主要由颗粒团聚控制，颗粒破碎动力学对 PSD 有很大影响，尤其是在聚合初期，它与聚集体竞争以降低反应器的脱流风险。此外，节点数对 PSD 仿真结果有很大影响，使用三个节点是最佳配置。在这个三相系统中，冷凝液体含量的增加提高了颗粒生长速率，从而影响了反应器的生产率和产品的性能，如平均粒径和最终 PSD。