关键词: 催化裂化装置, 沉降器, 料腿, 汽提段, 结焦

Abstract:

After the settler top cyclone separator is changed from soft connection to direct connection, the changes of equipment structure caused the changes of stripping oil and gas residence time and flow trajectory, the fluctuation of unit operating conditions, the reduction of feed oil atomization steam flow and other factors, resulting in coking in the leg and stripping section of the top cyclone separator of the settler. The following improvement measures are proposed: Restore the length of the balance pipe of the original design, control the relatively high stripping steam flow rate, make the residence time of stripping oil and gas less than 15 s, and ensure that there is no coking at the wing valve of the top cyclone separator of the settler, so as to make the blanking of the leg smooth; Avoid the processing feedstock containing more polycyclic aromatic hydrocarbons such as coking wax oil, which are prone to condensation and coking; The atomization steam of feedstock shall not be lower than the design value of the nozzle to ensure the atomization effect of the nozzle, meanwhile, the temperature of regenerator shall not be less than 680 ℃ to make the high boiling point components in the feedstock can be instant gasification; Increase the catalyst to oil ratio to contact the feedstock atomization droplet with more regenerators, and reduce the formation of coking precursors in thermal cracking reaction.

Key words: FCCU, settler, leg, steam stripping section, coking