非绝热式固定床反应器的参数敏感性及热失控临界参数

Parametric sensitivity and thermal runaway critical parameters in non-adiabatic fixed bed reactors

寻找安全有效的反应条件一直是绿色化工的重要研究内容之一。采用邻二甲苯氧化的反应动力学模型,分析了非绝热式固定床反应器的参数灵敏性和热失控行为,考察了非绝热式固定床反应器温度对冷却介质流量、进料温度和初始压力的敏感性。模拟计算结果表明,当反应进入敏感性区域后,反应器对冷却介质流量、进料温度和初始压力的改变极其敏感。采用系统散度判据(div>0)计算该反应的热失控临界操作参数,计算结果与文献中的判据进行了分析比较,得到类似的结果,但计算更简单。考虑冷却介质的影响,修正了div判据,得到更准确的热失控临界操作参数。研究结果表明,此判据能为反应器的设计及过程控制提供重要的参考依据。

Safe and effective reaction condition is one of the important issues in green chemical technology. Parametric sensitivity and thermal runaway behavior in non-adiabatic fixed bed reactors were analyzed by using a reaction kinetics model for ortho-xylene oxidation. The sensitivity of thermal behavior in a non-adiabatic fixed bed reactor was also examined with respect to cooling medium flow rate, feeding temperature and initial pressure. The simulation results showed that the non-adiabatic fixed bed reactor became extremely sensitive to small changes in cooling medium flow rate, feeding temperature and initial pressure when the reactor was operated in the sensitivity region of parameter space. The divergence （div） of the system was used to calculate the critical operating parameters and similar results were obtained in comparison with the criteria of literature. However, the divergence method was simpler than the existing criteria. Finally, the influence of cooling medium was taken into consideration to modify the div criterion, and more exact thermal runaway critical operating parameters were obtained. This criterion could provide good reference for reactor design and process control.