Why is it necessary to introduce nitrogen and maintain a slight positive pressure when opening the reactor?
Thread Content
As the title suggests, the reactor cover has been opened and it has been purged along with its temperature reduced to below 40°C; what is the purpose of introducing nitrogen? Also, according to the book, when the cover is opened, the 8-shaped blind flange at the outlet should be in the blocked position. Since it’s about to be opened, why is the blind flange still in place? What is its function? Third, it is said that after opening the cover, nitrogen gas needs to be introduced from above, and rainproof measures must be taken. What exactly is this nitrogen gas supply system? I earnestly ask the experienced master for his guidance! Thank you so much! !
It’s best to consult the on-site technical staff directly; they are obligated to train you. For reference.
Throughout the process of catalyst unloading or removal, nitrogen protection is required. The purpose of introducing nitrogen is to prevent the reduced-form catalyst from oxidizing upon exposure to air, as well as to protect it from moisture； Installing blind flanges on the outlet and inlet is a necessary isolation measure to prevent materials from flowing from one to the other ； A nitrogen belt is the rubber hose or flexible tube that connects the nitrogen pipelines ； After the nitrogen cover is opened, cover it with a plastic tarp to protect it from moisture and rain ； Working in confined spaces under anaerobic conditions requires a specialized team; personnel must wear long-tube positive-pressure breathing masks, and the air compressors used to supply oxygen must be under the supervision of a dedicated person ； Safety belts, rescue ropes, communication devices, and other standard safety measures for confined spaces.
Introducing nitrogen into the reactor is meant to prevent oxygen from entering it, thereby avoiding contact between the catalyst and oxygen. Injecting nitrogen at the reactor inlet serves to stop oxygen from reaching the systems ahead of the reactor; once connected, it enters the reactor. As for the nitrogen belt, I’m not sure about that – it would be best to take a screenshot and send it over for a look
Thank you so much! It was explained very clearly! ! Got it
One more question: The reactor has been cooled below 40 degrees. Will the catalyst still oxidize if it is exposed to air? Thank you!!
The reactor temperature drops to 40 degrees, but there may still be areas where the catalyst temperature is higher. In the past, when we removed the catalyst, we put it into ton bags; since it’s not possible to quantify whether there is reduced-form catalyst or not, or whether the temperature is too high, it’s necessary to use nitrogen for protection before packaging. Once packaged, the bags must be sealed quickly, as even a slight increase in temperature can cause the bags to heat up and result in the entire contents of the bag spilling out； Operators must wear long-tube respirators.
Normal-temperature hydrogenation catalysts can catch fire on their own over time due to the lack of inert gas protection; therefore, it has nothing to do with temperature. It is necessary to provide protection using CO2 or nitrogen, as well as through water sealing or oil sealing
It seems that only hydrogenation catalysts in their reduced state can self-ignite. Additionally, if iron sulfide is present in the hydrogenation catalyst, it may also cause self-ignition. Can catalysts in their oxidized state also self-ignite? Also, how to perform water sealing and oil sealing?