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

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.