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过程工程学报 ›› 2022, Vol. 22 ›› Issue (7): 944-953.DOI: 10.12034/j.issn.1009-606X.221234

• 研究论文 • 上一篇    下一篇

高温加压微型流化床内脉冲气射流扰动的数值模拟

张炜1, 刘文津1, 张玉明1*, 李家州1, 岳君容2   

  1. 1. 中国石油大学(北京)重质油国家重点实验室,北京 102249 2. 中国科学院过程工程研究所多相复杂系统国家重点实验室,北京 100190
  • 收稿日期:2021-07-27 修回日期:2021-09-29 出版日期:2022-07-28 发布日期:2022-08-02
  • 通讯作者: 张玉明 ymzhang@cup.edu.cn
  • 基金资助:
    国家自然科学基金;国家重点研发计划;中国石油大学(北京)科研基金资助;中国石油大学(北京)科研基金资助

Numerical simulation of pulsed feeding flow disturbance in high temperature pressurized micro-fluidized bed

Wei ZHANG1,  Wenjin LIU1,  Yuming ZHANG1*,  Jiazhou LI1,  Junrong YUE2   

  1. 1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China 2. State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2021-07-27 Revised:2021-09-29 Online:2022-07-28 Published:2022-08-02

摘要: 气固微型流化床反应分析仪由于其等温微分特性而被成功应用于反应动力学分析。目前该仪器多在常压条件下应用,在加压条件下的使用特性尚未明确。微型流化床为该仪器核心部件,通过计算流体力学方法深入研究其在高温加压条件下的脉冲进样行为有着重要意义,可揭示脉冲进样气对床层流化状态扰动的影响规律,进而为该仪器的高压使用与优化提供理论认识与指导。本工作基于双流体模型模拟床层流化,对加压条件下微型流化床的脉冲进样进行了三维数值模拟,并提出进样管结构改进方案。模拟结果表明,所建立的三维模型能够准确捕捉到微型流化床的压降,符合实验结果。温度与压力对脉冲进样气造成的床层扰动有着相反的影响规律,压力增大将引起脉冲进样气动能增加,进而导致对床层流化扰动加剧,而温度升高则会减弱对床层的扰动。通过对脉冲进样管进行轴向以及径向的扩张,可使扩张导致的气流速度减小效果强于无滑移壁面条件导致的气流速度增大效果,从而减小脉冲进样气末端速度,进而削弱其对床层的扰动。相比径向扩张,轴向扩张对扰动的削弱作用更为有效,因此脉冲进样管的改进应以轴向扩张为主。

关键词: 微型流化床, 进样管, 加压, 数值模拟, 双流体模型

Abstract: The gas-solid micro-fluidized bed reaction analyzer (MFBRA) has been successfully applied to the analysis of reaction kinetics because of its isothermal differential characteristics. However, its application is limited to normal pressure conditions at present, and its applications under pressurized conditions are not established yet. Micro-fluidized bed (MFB) is the core part of an MFBRA. It is of great significance to investigate the behavior of the pulsed feeding gas injection in an MFB under high temperature and high pressure conditions by computational fluid dynamics. It is in gread need to reveal the disturbance of the pulsed feeding gas to the bed material fluidization, deepen the theoretical understanding and provide guidance for the usage, and optimization of a pressurized MFB. In this work, a three-dimensional simulation was performed to simulate the pulsed feeding gas injection into an MFB under high temperature pressurized conditions, and to improve the structure of the feeding tube. The fluidization inside the MFB was described by two-fluid method (TFM). It was confirmed that the model adopted here captured the pressure drop inside an MFB, agreed with experimental data. It was found that temperature and pressure had opposite effects on the fluidized bed disturbance caused by the pulsed feeding gas. Increasing the pressure could enlarge the disturbance of the feeding gas to bed fluidization because the kinetic energy of the feeding gas increased, while increasing the temperature could reduce the fluidized bed disturbance. By expanding the feeding tube in axial and radial direction, the decreasing effect of gas velocity caused by tube expansion could be stronger than the increasing effect of gas velocity caused by the non-slip wall condition. Therefore, the terminal velocity of the feeding gas decreased, and its disturbance to the bed could be weakened. Compared with radial expansion, axial expansion was more effective to weaken the disturbance and should be the main method for improving the structure of the feeding tube.

Key words: micro-fluidized bed, feeding tube, pressurized, simulation, two-fluid model