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过程工程学报 ›› 2021, Vol. 21 ›› Issue (12): 1419-1429.DOI: 10.12034/j.issn.1009-606X.221006

• 流动与传递 • 上一篇    下一篇

烯烃催化裂解反应器局部颗粒堆积结构的颗粒解析模拟

许飞1,2， 陈飞国1， 刘晓星1,2， 吴昊2,3， 鲁波娜1,2*， 刘志成4， 滕加伟4
  

  1. 1. 中国科学院过程工程研究所，北京 100190 2. 中国科学院大学中丹学院，北京 100049 3. 丹麦科技大学化学与生化工程系, 孔根斯 灵比 2800, 丹麦 4. 中国石油化工股份有限公司上海石油化工研究院，上海 201208
  • 收稿日期:2021-01-05 修回日期:2021-02-08 出版日期:2021-12-28 发布日期:2022-03-28
  • 通讯作者: 鲁波娜 bnlu@ipe.ac.cn
  • 作者简介:许飞(1996-)，山东省陵县人，硕士研究生，化学工程专业，E-mail: xufei18@ipe.ac.cn；鲁波娜，通讯联系人，E-mail: bnlu@ipe.ac.cn.
  • 基金资助:
    国家自然科学基金项目;国家自然科学基金项目;中国科学院洁净能源先导科技专项资助;中国石油化工股份有限公司上海石油化工研究院委托课题

Particle-resolved simulation of typical packing structures in olefin catalytic cracking reactor

Fei XU1,2,  Feiguo CHEN1,  Xiaoxing LIU1,2,  Hao WU2,3,  Bona LU1,2*,  Zhicheng LIU4,  Jiawei TENG4   

  1. 1. Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China 2. Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, China 3. Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark 4. SINOPEC Shanghai Research Institute of Petrochemical Technology, Shanghai 201208, China
  • Received:2021-01-05 Revised:2021-02-08 Online:2021-12-28 Published:2022-03-28
  • Supported by:
    ;the "Transformational Technologies for Clean Energy and Demonstration" Strategic Priority Research Program of the Chinese Academy of Sciences;the Project supported by SINOPEC Shanghai Research Institute of Petrochemical Technology

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摘要： 烯烃催化裂解固定床工艺中的反应过程对压力敏感，深入研究催化剂堆积颗粒结构中的流动及压力分布对优化固定床结构及操作参数有重要意义。颗粒解析模拟方法广泛用于固定床内堆积结构的模拟，可以准确描述堆积结构中的流体力学行为，但对于复杂堆积结构网格生成困难。采用基于多孔介质模型的浸入边界法(PMM-IBM)结合网格自适应，实现了对固定床堆积结构的颗粒解析模拟，既解决了网格划分困难的问题，又节省了计算资源。采用网格自适应技术后，与均匀网格相比，堆积结构的网格总数减少大约80%。通过与贴体网格法的单颗粒表面受力分析对比，确定了此浸入边界法的关键模拟参数。随后模拟预测了三种床层与颗粒直径比值条件下堆积结构的空隙率及其内部的压力及流动分布。研究表明，堆积结构空隙中的局部轴向速度的最大值可以达到入口速度的10倍以上，轴向平均速度的径向分布与轴向平均空隙率分布一致，均成震荡衰减趋势。除此之外，预测的床层压降与Reichelt经验关联式结果较为吻合。在此基础上，耦合单颗粒内扩散和烯烃裂解的主反应，预测了反应物随孔径和孔隙率的变化，为进一步考虑外流场的变化奠定了方法基础。

关键词: 固定床, 浸入边界法, 多孔介质模型, 网格自适应, 计算流体力学, 数值模拟

Abstract: Understanding the flow behaviors and pressure distribution in the interstitial void space among particles is of great importance for improving operating parameters of fixed bed chemical processes, like OCC (olefin catalytic cracking) process. Particle-resolved simulation method is extensively adopted in simulations of fixed bed reactors due to its ability of accurate describing fluid dynamics in packing structures, but its mesh generation process is rather difficult when the packing structure is complex. This study realized a particle-resolved simulation method of typical packing structures in the OCC fixed bed reactor through developing an immersed boundary method, which was based on the porous media model (PMM-IBM) and mesh adaption technology. This method simplified mesh generation process and reduces the computational cost. Compared to the uniform mesh, the total mesh number of the packing structure was reduced about 80% after the mesh adaption. The key parameters of the PMM-IBM were first determined by comparing the forces acting on the particle surface between PMM-IBM and body-fitted mesh method. Further, for three different bed-to-particle diameter ratios, the voidage, pressure and velocity distribution of the packing structures were simulated. It was found that the maximum local axial velocity in the packing structures was 10 times higher than the inlet velocity. The radial distribution of the average axial velocity was consistent with that of the average axial voidage, which showed an oscillation attenuation trend along the center of the bed. Moreover, the pressure drop was almost consistent with the results from Reichelt empirical correlation. Finally, the mass transfer and the main reaction of OCC were considered. The mass fraction variation of the reactant according to pore size and porosity was predicted, which provided the possibility for including the external flow structures and variations in future work.

Key words: fixed-bed, immersed boundary method, porous media model, mesh adaption technology, computational dynamic fluid, numerical simulation