Why is pressure relief required for emergency shutdown reactions in hydrogenation?

Because the reaction cannot be stopped instantly.

The heat in the reactor is carried away by the circulating hydrogen; during an emergency shutdown, the circulation of hydrogen is interrupted, and the heat generated within the reaction cannot be removed by the circulating hydrogen, resulting in a disruption of the thermal balance. If pressure relief is not implemented, the reactor is very likely to overheat.

Sometimes if you think about it the other way around, what would be the situation if there was no way to relieve stress? What was said upstairs is very clear; I hope you can understand it~

The teacher ordered an immediate shutdown; was stopping the circulating hydrogen done to prevent the reactor from overheating or to avoid catalyst reduction?

Hydrogenation is an exothermic reaction; once an emergency shutdown occurs, the hydrogenation reactor will overheat. The only way to remove the heat carried by the oil and gas flowing within the reactor is through emergency pressure relief.

Emergency pressure relief is intended to reduce reaction pressure and prevent the reactor from overheating. Another aspect is to allow circulating hydrogen to flow, thereby carrying away the heat of reaction and reducing the reaction depth

The main concern is overheating due to the reaction. Catalyst reduction is generally carried out when the catalyst is still in its oxidized state, in pure hydrogen at a temperature of 230 degrees (with the actual operating temperature usually being lower than 230 degrees). Catalysts that have already been vulcanized are not as fragile as one might think; they are not so easily reduced.

The reaction heat is removed through forced circulation of waste hydrogen~~~~ The reaction cannot be stopped instantly; once the hydrogen circulation pump stops, circulation can only be maintained by the waste hydrogen~~~

You should ask why an emergency shutdown is necessary for this question Or what exactly constitutes an emergency shutdown? Emergency shutdowns are usually required in cases of serious issues such as excessive temperature rise, leaks, or fires. Shutdowns of hydrogen compressors, feed pumps (for fluidized bed systems), or power outages can all be factors that lead to excessive temperature rise in the bed. Once overheating occurs, large leaks or fires represent uncontrollable situations; since the entire system becomes uncontrollable, it is necessary to shut down the operation \"urgently\", otherwise shutdown would be carried out according to normal procedures. As for the role of pressure relief, as everyone above has explained quite clearly, it is simply to remove the heat generated by the reaction through pressure release, thereby preventing the catalyst from coking and becoming inactive. It also helps to keep the reaction system in a safe state (what would happen if the temperature rises to the limit at which the reactor’s steel can withstand it, combined with such high pressure?) ).

This post was last edited by ynan on 2015-8-7 at 17:03. Emergency pressure relief is used to remove the heat generated by the reaction, reduce pressure, disrupt the conditions necessary for the hydrogenation reaction, and prevent catalyst sintering as well as damage to the reactor materials due to excessive temperatures