Abstract
Petri nets have been successfully used for modeling, analysis, simulation, scheduling and control of manufacturing systems. Petri nets, used as a mathematical and graphical tool, provide a powerful environment in which all the complicated mathematical relations between operations can be seen graphically. Additionally when using Petri nets, modeling and resource allocation can be done simultaneously. Petri nets can also provide a powerful approach to decision making for process operations. A review is provided detailing the applications of Petri net in decision making and resource allocation. Furthermore, insight is given into the use of Petri nets in process operations, through the use of hierarchical timed place Petri nets for intelligent process operations management in large scale processing plants.