Steam injection into the riser during FCC two-unit interlock
Thread Content
This post was last edited by liaifeng on 2020-4-24 at 18:09. In the event of an accident, the two-device interlock system of the FCC typically injects steam into the lift pipe (in a considerable amount). As a result, large quantities of steam enter the distillation tower, causing it to overpressurize. At that point, the flare valve at the inlet of the compressor opens, and a large amount of steam is sent to the flare system. I would like to ask everyone: does a large amount of steam really enter the flare system after steam injection via interlock between the two devices? What impact will it have? I would also appreciate your guidance; thank you!
Do you think the cooling unit at the top of your tower is fake? Even though a lot of steam passes through it, it still turns into water...
The feed was already cut off at the time of the accident, and that amount of steam, compared to the feed volume, would not cause overpressure in the distillation tower. The flare was activated during the accident to remove the oil and gas from the reaction system, in order to prevent backflow; when steam turns into water, there will be much more acidic water!
Well, thank you. What if there’s a power outage? If both the water cooling and air cooling at the top of the tower stop working, won’t the distillation tower experience overpressure very quickly?
Well, thank you. What if there’s a power outage? If both the water cooling and air cooling at the top of the tower stop working, won’t the distillation tower experience overpressure very quickly?
The three-phase separator at the top of the tower and water/air cooling solve the problems
Well, thank you. In accident conditions such as a power outage, cooling systems like air cooling stop working, and heat extraction from the middle section also ceases; wouldn’t this cause the top of the tower to experience rapid overpressure?
Under normal circumstances, the steam pressure will decrease； If it doesn’t drop, after steam has been flowing for over ten minutes, it’s time to start reducing or closing the valve to limit the amount of steam.
Are you saying that all power in the entire plant will be cut off... Isn’t there a backup circuit that can be activated?
At the inlet of a catalytic compressor under normal pressure, the flare valve will open, while the safety valve will not activate