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为预防间歇式反应器热失控风险,以恒温间歇式丙酸异丙酯合成反应为原型,利用反应量热仪(RC1e)获得不同冷却温度下反应放热特性及热动力学参数,并对计算流体力学(CFD)软件Fluent模拟结果进行试验验证。基于经验证的CFD耦合模型,对反应过程中搅拌和冷却失控情景进行模拟分析,分别从搅拌转速、冷却温度以及冷却流速失控3方面,研究失控情景对反应温升的影响。结果表明:反应温升对不同失控情景存在参数敏感性,其中冷却流速对反应温升影响较大,较低的入口冷却流速直接促使局部换热死区的形成,使失控时间相对标准工况提前近1/5,温度提高近22℃;以反应失控判据Chaos准则为警报标准,确定反应器最佳温度探测器应安装在反应液系内部远离冷却入口且靠近液面1/3处及以上的位置。
In order to prevent the risk of thermal runaway in batch reactors, a constant temperature intermittent synthesis of isopropyl propionate was used as a prototype. The reaction exothermic properties and thermodynamic parameters at different cooling temperatures were obtained by using a reaction calorimeter (RC1e) Fluid dynamics (CFD) software Fluent simulation results for experimental verification. Based on the validated CFD coupling model, the scene of uncontrolled mixing and cooling during the reaction was simulated and analyzed. The effects of uncontrolled scenarios on the temperature rise of the reaction were investigated respectively from stirring speed, cooling temperature and cooling rate control. The results show that the reaction temperature has parameter sensitivity to different runaway scenarios, and the cooling flow rate has a great influence on the reaction temperature rise. The lower inlet cooling flow rate directly leads to the formation of local heat transfer dead zone, Nearly 1/5, the temperature increased by nearly 22 ℃; Chaos criteria for the reaction out of control criteria for the alarm criteria to determine the optimal reactor temperature detector should be installed inside the reaction solution away from the cooling inlet and close to the liquid level at 1/3 and above s position.