What to do when insufficient pressure exists to completely drain the oil during the shutdown of the absorption stabilization system?
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In July, the unit was shut down for maintenance. Due to the short time available, the large volume of work involved, and the fact that the operations had to be carried out at night, insufficient pressure was available during the process of draining oil from the absorption stabilization system, which resulted in a lot of work being required to displace the oil with water later on. Do anyone have any good suggestions or methods?
Typically, stabilizer towers are equipped with strong pressure discharge systems, which can easily solve your problem.
Pressurize by purging with nitrogen. Some plants also connect a draw line from the bottom of the tower to the inlet of the tower top reflux pump to remove oil.
Under nitrogen pressure, carry out a technical modification after shutdown: add a cross-link between the reboiler at the bottom of the stabilizer and one of the bottom pumps (we use the rich absorption oil pump; the choice depends on the layout on site), so that it can be used for pressurization during shutdown.
Could you be more specific? What is the nitrogen pressure in kilograms? Is medium-pressure nitrogen required? We rely on the system’s pressure to remove oil automatically, but sometimes the oil isn’t removed thoroughly enough
What do you mean? Could you explain it in more detail, or even draw a sketch?
Generally, the oil withdrawal ends up concentrating in the stabilizer, where insufficient pressure makes it difficult to remove the oil; in such cases, the steam stabilizing pump can be started to draw out the oil from the bottom of the tower and the reboiler. This forced extrusion device line, as well as the absorption and stabilization systems, all follow this process, and the operator in this position should be aware of it.
I still don’t understand what you mean by that forced discharge device line; in our stable operation areas, there is always unqualified oil that is sent to the tank area