1 Timed Colored Petri Net Model for Analyzing Operating Procedures for Batch Processes

Due to the recent diversification of consumer demands for products, batch processes are viewed as a promising process employed in such circumstances. However, because the limited numbers of equipment and facility are to be shared among multi-item products, it is essential to discover serious conflicts and deadlocks that incur various problems such as decrease in operating rates, due date delays of products, etc. For this purpose, in this study, we have proposed a simulation-based approach. It is realized by extending the foregoing colored Petri net model to a timed colored Petri net model so that we can carry out appropriate analyses through taking time dependent behaviors into account. In its modeling, we also introduced a hierarchical structure for describing conveniently a family of similar models and for dealing with complexity in real world applications. In its development, we assumed that conditions regarding master recipe and unit procedure are given as those consistent with S88 standard. Through the discovery of various conflicts and bottlenecks, we can take proper actions for the improvement in the procedure and equipment requirement in batch processes. Finally, to confirm effectiveness, we provide a case study associated with a two-step polymer process, and conclude with the notification on the special advantages of the proposed approach