Responsibilities of process and other departments in the factory

Hello, I am a chemical engineering student. Recently, I had the opportunity to tour a petrochemical plant during a technical field trip organized by my university.

If I recall correctly, we had the chance to chat with engineers from the Utility Process department—which falls under Technical Services—covering areas like process optimization and process engineering; however, I couldn't quite grasp who played what role or what their specific duties entailed, so I wasn't able to fully evaluate the situation. What are the differences from a production engineer? What skills and qualifications should chemical engineering graduates possess if they wish to work in these or similar departments?