CFD modeling and simulation of industrial scale olefin polymerization fluidized bed reactors
CFD modeling and simulation of industrial scale olefin polymerization fluidized bed reactors
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DOI：
10.1016/j.cej.2014.11.058
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发表时间：
2015-03
影响因子：
15.1
通讯作者：
S. Schneiderbauer;S. Puttinger;S. Pirker;P. Aguayo;Vasileios Kanellopoulos
中科院分区：
文献类型：
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作者：
S. Schneiderbauer;S. Puttinger;S. Pirker;P. Aguayo;Vasileios Kanellopoulos
提出了一种用于烯烃聚合流化床反应器工业规模数值模拟的双流体模型。然而，工业规模反应器的完全解析模拟仍然几乎不可行。因此，我们使用亚网格模型（Schneiderbauer和Pirker，2014）来计算相间阻力和固体应力，以说明使用粗网格时小的未分辨结构对大分辨尺度的影响。考虑到高密度聚乙烯（HDPE）的宽粒度分布，对拖曳力的亚网格校正进行了修改。此外，固体应力的子网格修改适于包括聚合物的流变性质。一方面，通过对实验室鼓泡流化床的粗网格模拟，将床层膨胀、气泡尺寸和气泡上升速度与实验数据进行比较，验证了模型的有效性。另一方面，将该模型应用于工业规模流化床-移动床反应器组合体的粗网格模拟。计算结果表明，该模型与实验数据吻合较好，能较好地模拟床层平均空隙率、气泡直径和气泡上升速度。最后，研究了在移动床反应器中注入阻挡气体以分离流化气体和气体的影响。
A two-fluid model for the numerical simulation of industrial scale olefin polymerization fluidized bed reactors is presented. However, a fully resolved simulation of industrial scale reactor is still nearly unfeasible. We, therefore, use sub-grid models (Schneiderbauer and Pirker, 2014) for the interphase drag and the solids stresses to account for the effect of the small unresolved structures on large resolved scales when using coarse grids. The sub-grid correction for the drag force is modified to consider the wide particle size distribution of high density polyethylene (HDPE). Furthermore, the sub-grid modification for the solids stresses is adapted to include the rheological properties of the polymer. On the one hand, the presented model is validated in the case of the coarse grid simulation of lab-scale bubbling fluidized bed by comparing bed expansion, bubble size and bubble rise velocities with experimental data. On the other hand, the model is applied to the coarse grid simulation of an industrial scale fluidized bed – moving bed reactor assembly. The numerical results demonstrate that our model reveals fairly good agreement with experimental data of average bed voidage, bubble diameters and bubble rise velocities. Finally, the impact of a barrier gas injection is studied, which is aimed to separate the fluidization gas from the gas in the moving bed reactor.