In the flue gas energy recovery system of catalytic cracking unit

the opening of slip valve is a key parameter.The bigger its value

the safer the system

however

the higher the energy consumed.In this paper

the risk decision theory is used to decide the safe opening of slip valve.Based on the risk probability analysis by Delphi inquiry

which is further corrected by Bayes’ theory

the opening value of the valve is determined by means of the decision tree method.It was used satisfactorily at Jinzhou Petro-Chemical Co.