In an exothermic reaction with limited cooling, will the vessel be able to contain the reaction?

In an exothermic reaction with limited cooling, will the vessel be able to contain the reaction?

• A. Only if cooling is maintained at or above a specific rate
• B. Yes, the vessel will be able to contain the reaction
• C. It depends on reactor design and venting
• D. No, the vessel will not be able to contain the reaction

Answer: (D)

When a reaction is strongly exothermic, heat is being released as it proceeds. If cooling is limited, the amount of heat removed is less than the heat being generated. Temperature then starts to rise. Since many reaction rates increase with temperature (Arrhenius behavior), the reaction speeds up as the temperature goes up, producing even more heat in a self-amplifying loop known as thermal runaway. As heat accumulates, pressure can also rise if gas or vapor is evolved, and the vessel must handle this pressure. If cooling cannot keep up and the pressure relief system is overwhelmed, the vessel cannot safely contain the reaction. Therefore, with limited cooling, containment cannot be guaranteed, and the vessel is not expected to safely hold the runaway reaction.

When a reaction is strongly exothermic, heat is being released as it proceeds. If cooling is limited, the amount of heat removed is less than the heat being generated. Temperature then starts to rise. Since many reaction rates increase with temperature (Arrhenius behavior), the reaction speeds up as the temperature goes up, producing even more heat in a self-amplifying loop known as thermal runaway. As heat accumulates, pressure can also rise if gas or vapor is evolved, and the vessel must handle this pressure. If cooling cannot keep up and the pressure relief system is overwhelmed, the vessel cannot safely contain the reaction. Therefore, with limited cooling, containment cannot be guaranteed, and the vessel is not expected to safely hold the runaway reaction.