Emergency nitrogen storage tank for air separation
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Experts, is it necessary to install a nitrogen emergency storage tank at the air separation unit of the PX aromatic compounds plant? A liquid nitrogen storage tank has been installed. Is there any basis for determining whether an emergency nitrogen storage tank is necessary for nitrogen supply in refining plants?
I’m not very familiar with PX aromatic units and refining units, but in the case of air separation systems, there are liquid nitrogen storage tanks, liquid nitrogen pumps, and vaporization devices; thus, a means for supplying nitrogen is already available. In that case, it would be redundant to design an additional nitrogen storage tank. As I don’t know much about your main units, this is just my personal opinion.
The nitrogen storage tank serves two purposes: one is to act as a buffer to maintain stable pressure in the nitrogen pipeline network, and the other is to store gas for emergency use; when the nitrogen pump or compressor fails, the gas stored in the tank can supply the pipeline network with gas for a period of time during emergencies. It takes some time for the liquid nitrogen in the liquid nitrogen storage tank to convert into gas for external supply, and during this period, an on-site gas nitrogen storage tank is needed to ensure a continuous supply of nitrogen.
Well, it is said to be used as a backup in case of a sudden interruption in normal nitrogen supply. How is this nitrogen storage tank generally designed to provide a certain duration of nitrogen supply? Are there any standards or guidelines? I’ve never seen such a storage tank installed in the air separation and air compression station of an oil refining plant. Thank you!
Design it based on how soon you can drive again. Of course, the time during which the vehicle was stationary due to equipment damage cannot be counted.
As for the nitrogen gas cylinders, they probably won’t last that long; it’s enough to leave some time for the emergency nitrogen pump to start supplying gas, thereby avoiding a gas supply interruption~~
I really hadn’t paid attention to this standard specification before. There is a standard range of around 10–20 minutes for instrument air. As for nitrogen used for safety purposes, it should be determined based on the nature of the enterprise: first, check whether there is a backup nitrogen system in case of an accident; if so, only the startup time of that emergency nitrogen system needs to be considered； 2. For an accident-free nitrogen system, it is sufficient to consider the safety measures required to address various issues after a plant-wide emergency shutdown: ensure that whatever needs to be released is properly released and that whatever needs to be replaced is replaced, so as to guarantee safe handling of the situation after the shutdown.