Design and implementation of gain scheduling decentralized PI/PID controller for the fluid catalytic cracking unit

Abstract

Fluid Catalytic Cracking Unit (FCCU) is a technique where raw crude oil is transformed into lighter petroleum products. It is a challenging problem in the refining industry. The FCCU is a non-linear and interactive process as they are interdependent on one another. This process also describes the intercommunication of the controllers by providing a decentralized controller. The Proportional-Integral-Derivative controller (PID) is an easy way of controlling and implementing the process. In this paper, the performance of FCCU with Gain Scheduling Decentralized Proportional-Integral (GSD-PI) and Gain Scheduling Decentralized PID (GSD-PID) controllers are compared, and the output will prove that the GSD-PID controller is well organized over GSD-PI Controller. The result shows that the GSD-PID controller exhibits the best performance with evaluation criteria like Integral square error, Integral absolute error, and Integral time absolute error. A small change to the PI Controller will drastically affect the process but in PID there is no effect over them. The real-coded Genetic Algorithm (GA) is utilized to determine optimal values for GSD-PID and GSD-PI controllers. The executed output proves that the real-coded GA tuned GSD-PID control scheme has realized the performance by the system with smaller overshoot, effects of interaction is minimum and good disturbance rejection are noted.