Abstract
In the control of an actual plant, PID control methods are still popular in industrial applications. However, due to their poor ability to react appropriately in a dynamic operational environment, they sometimes fail to control the actual plant, including operations such as feed oil changing and process line changing.
On the other hand, well-experienced operators can easily manage these operations to appropriately manipulate the set points or to adjust the output of the PID controller using their experience and knowledge.
In an ethylene plant, the decoking operation of the decomposition furnace is highly unstable. To mimic the well-experienced operator's procedures, we have developed a combined system that consists of an intelligent control and a PID control. The intelligent controller plays the role of the well-experienced operator. We applied a hierarchical system to the ethylene plant in order to demonstrate its effectiveness for the decoking process.
