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过程工程学报 ›› 2022, Vol. 22 ›› Issue (8): 1053-1060.DOI: 10.12034/j.issn.1009-606X.221317CSTR: 32067.14.jproeng.221317

• 研究论文 • 上一篇    下一篇

搅拌槽中酯化反应热失控的CFD模拟

陈毕清1,2， 管小平2， 杨宁2*， 白丁荣1
  

  1. 1. 沈阳化工大学环境与安全工程学院，辽宁 沈阳 110027 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:2021-10-08 修回日期:2021-11-19 出版日期:2022-08-28 发布日期:2022-08-28
  • 通讯作者: 陈毕清 chenbiqing520@163.com
  • 作者简介:陈毕清(1996-)，男，浙江省金华市人，硕士研究生，安全工程专业，E-mail: chenbiqing520@163.com；通讯联系人，杨宁，E-mail: nyang@ipe.ac.cn.

CFD simulation of thermal runaway esterification reaction in stirred tank

Biqing CHEN1,2,  Xiaoping GUAN2,  Ning YANG2*,  Dingrong BAI1   

  1. 1. School of Environmental and Safety Engineering, Shenyang University of Chemical Technology, Shenyang, Liaoning 110027, China 2. State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2021-10-08 Revised:2021-11-19 Online:2022-08-28 Published:2022-08-28
  • Contact: Bi-Qing CHEN chenbiqing520@163.com

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摘要： 热失控是化工过程中常见的安全风险之一。在间歇釜式反应器中，桨叶的机械转动可以增强流体的循环流动、湍流强度、混合程度以及传热，进而有效防范热失控。防控效果与反应器结构和搅拌桨型密切相关。针对丙酸异丙酯酯化反应，采用计算流体力学模拟研究了桨型(Rushton桨、30o PBT桨及60o PBT桨)、转动方向和挡板对釜式反应器内温度演化的影响，从流动结构方面分析了原因。基于散度的失控判据比较了三种搅拌桨抑制热失控的能力，抑制能力为Rushton桨＞30° PBTD桨＞60° PBTD桨。本研究可为搅拌反应器热失控的优化设计提供一定的理论依据。

关键词: 热失控, 酯化反应, 搅拌槽, 计算流体力学

Abstract: Thermal runaway is one of the common risks in chemical process safety. Thermal runaway accidents of various scales cause a lot of economic losses every year. The runaway of batch stirred reactor is particularly dangerous due to the single way to control the reaction rate.From the view point of intrinsic safety, optimal design of reactor and operating conditions can fundamentally prevent thermal runaway. In batch-operated stirred tank reactors, impeller rotation can enhance flow circulation, turbulence intensity, mixing degree, and heat transfer, thus effectively preventing thermal runaway. In this work, according to the esterification reaction of propionic anhydride and isopropanol to produce isopropyl propionate and propionic acid under the catalysis of concentrated sulfuric acid, CFD simulation was carried out to simulate the thermal runaway esterification reaction in stirred tanks. The effects of impeller type (Rushton impeller, 30° pitched blade turbine impeller and 60° pitched blade turbine impeller), rotation direction, and baffle on the temperature evolution were studied. The simulated flow structures were used to explain the effects. Furthermore, divergence criterion was used to compare the performance of resisting thermal runaway for different impellers. The simulation showed that the radial flow agitator performed better than the axial flow agitator at the same rotation speed, and the performance order was Rushton impeller>30° PBTD impeller>60° PBTD impeller. For the 30° PBT impeller, when the operating mode changed from PBTD to PBTU, the capability to resist thermal runaway weakens, though the number of circulation zone increased. The situation of 60° PBT impeller was similar to that of 30° PBT impeller. The addition of baffle can substantially improve the thermal control in the reactor. This research provided fundamentals for design, optimization, and scale-up of reactors.

Key words: thermal runaway, esterification reaction, stirred tank, computational fluid dynamics