Temperature control of catalytic cracking process

Fluid Catalytic Cracking Unit (FCCU) is the most important conversion process used in petroleum refineries. It is a very complex interactive process used to convert the high-boiling and high-molecular weight hydrocarbon fractions of petroleum crude oil to more valuable gasoline, diesel etc‥ It is very difficult to model and control the FCC process because of large process scale and complex kinetics of cracking and coke burning reactions. Based on basic energy balance equation the mathematical model of reactor and regenerator systems have been carried out. The input variables for the control system are the reactor and regenerator temperatures. Decouplers were designed, which is used to eliminate the interaction effects between the control loops. An optimal controller for highly non-linear, inter dependent FCCU process has been designed. The performance of FCCU with decentralized PID control scheme is compared with the optimal control scheme using MATLAB/SIMULINK.