Catalytic cracking absorption and stabilization system shutdown purging medium
Thread Content
Steam is used for purging during the shutdown of the catalytic cracking absorption and stabilization system. Since the operating temperature in this system ranges from 20 to 200 degrees, and the temperature in the overhead pipelines is around 20 degrees, it is possible that using steam for purging during shutdown could cause the overhead pipelines and their supports to overheat and shift. If steam purging is not used, can nitrogen purging be used instead? Note that purging is generally carried out for the purpose of shutting down operations for maintenance work. Let’s all come and discuss how to do it.
In the north, steam purging is generally required when winter equipment is shut down. Steam temperature does not cause deformation or displacement of the equipment. Blowing with steam is no problem. When purging with nitrogen, it is generally necessary to ensure that there are no substances prone to crystallization in the pipelines, as well as no viscous liquids or those containing many impurities. That’s necessary. It is also not acceptable to use nitrogen purging in confined spaces, as it can cause suffocation and is extremely dangerous!
Everything I’ve dealt with has been purged using steam, so nothing like what I was worried about happened
When the absorption stabilization system is shut down, it can be purged completely with steam, so there’s no major issue. Blowing with nitrogen is only used at startup to displace air and pressurize. Steam can cause some displacement in the low-temperature pipelines at the top of the tower, but this has been taken into account during process design and installation, so it will not affect the safety of the facility. Furthermore, purging with nitrogen cannot completely displace the liquid hydrocarbon system, as liquid hydrocarbons are denser than nitrogen.
Does nitrogen purging remove the liquefied gas and gasoline components completely? Assume that the purging flow rate and time are sufficient, and the condensate is removed in a timely manner.