(1) The vibration of fractionator was eliminated by decoking the oil gas line.

(2) The practical application for a hydrocracker fractionator illustrates that the proposed method is useful to monitor the quality specifications in chemical processes.

(3) The operation and control interaction analysis between main fractionator and stabilizer of FCCU was studied.

(4) Serious coking occured at the fractionator oil and gas inlet in FCC unit of the No.

(5) A new method establishing models of FCC main fractionator was proposed.

(6) In this adopted to simulate the whole flow that is main fractionator system and absorption - stabilization system.