Interlock control for hazardous processes,
Thread Content
There is a hazardous process that requires interlock control. Since liquid nitrogen is used for cooling, it’s not clear whether, in the event of overtemperature or overpressure, the liquid nitrogen valve should be closed, opened, or some other action taken I would appreciate your advice. Thank you!
Use liquid nitrogen to cool the reaction tank? Just open the valve when there’s over-temperature or over-pressure.
I’m worried that if opening the valve still doesn’t prevent an accident, it could cause people to suffocate.
Liquid nitrogen is used to cool the reactor; in case of overtemperature, the liquid nitrogen valve should be activated via interlock； As for your concern about suffocation, oxygen concentration control instruments can be installed around to work in series with liquid nitrogen control valves in order to regulate the amount of nitrogen supplied.
I don’t know what the pressure level in your reactor is. If temperature and pressure cannot be controlled, then the safety valve should activate, preventing any leakage of liquid nitrogen. If the safety valve doesn’t activate and the reactor explodes, there would be no one alive at the scene, and the leakage of liquid nitrogen wouldn’t be a problem either, as it could even help put out the fire.
I think the valves used to cool the reaction vessel should be set to an emergency open position, so that in cases of power outages or a lack of instrument air, the valves remain open and prevent the vessel from overheating or overpressuring and getting out of control.
I think the valves used to cool the reaction vessel should be set to an emergency open position, so that in cases of power outages or a lack of instrument air, the valves remain open and prevent the vessel from overheating or overpressuring and getting out of control.
Yes, in theory it should be started in an accident scenario, but nitrogen is a bit special as it can cause secondary damage, so it’s not clear what to do.
Is secondary damage a concern due to nitrogen pressure or nitrogen leakage?
When it comes to using liquid nitrogen, it is simply used to cool the reaction vessel; if there are concerns regarding the dangers associated with nitrogen, other cooling methods can be employed, depending on the temperature required for the reaction. In our processes such as diazotization, oxidation, and hydrogenation, an interlock mechanism activates the coolant valve when the temperature exceeds a certain level, just like opening a liquid nitrogen valve.