Abstract:

Distributed Control System (DCS) is a major part of the control structure present in modern manufacturing systems as evidenced by its wide-spread use in many industries such as refining, chemical, pharmaceutical, mining, power, food, pulp and paper, and printing. DCS consists of integrated computer system that reads sensor data and writes to final control elements and stores process data in a historian.

This paper describes our efforts to incorporate the Honeywell Experion DCS software into the chemical engineering curriculum in a Problem-Based Learning (PBL) environment, in which realistic problems and open-ended questions are given as a motivation, small independent working groups are organized, and dialogue among the students is encouraged. In the PBL problem development, the DCS demonstration lab is coupled with Aspen Tech’s HYSYS dynamic process simulation to reflect the operating plant. First, dynamic simulation for a reformate stabilizer tower was created. Second, a HYSYS table to map simulation variables to DCS tags was configured. Third, a C++ program was started to automate HYSYS and connect it to the DCS. During the course of this project, the faculty modified course rubrics and outcome assessments in CHEN 4331& 4332 (Process Control I & II), CHEN 4150 (Process Control Laboratory), CHEN 4350 (Advanced Analysis), and CHEN 4410 (Reaction Kinetics). DCS-based modules are developed as a platform for teaching dynamics, basic/advanced PID control schemes, controller tuning, alarm rationalization, data mining, and reactor analysis. We found that this approach provided students with a better grasp of fundamentals as well as industrial practices through hands-on learning experiences.

In Process Control I, students working on the feedback PID control are granted with either an operator or an engineer account to access the DCS. The performance of temperature, flow, and composition control under various feed disturbances and tuning parameters were examined. In Process Control II, same tasks will be performed under advanced PID (ratio, cascade, and feedforward) control schemes. In the Process Control Laboratory, students were asked to distinguish between alarms which should be enunciated and alarms which should be logged, to classify potential alarms and choose an appropriate alarm priority based on operator response times and the consequence of inaction, to understand how alarm set points should be determined, and to use DCS tools to review chemical process event and historical data. In the CHEN 4350 Advanced Analysis class, students will be taught problem solving using this environment to analyze and interpret dynamic chemical plant operating data in order to troubleshoot plant problems. The emphasis of this analysis is on troubleshooting, safety analysis, incident investigation, and process improvement. The DCS will also be used in the Reaction Kinetics (CHEN 4410) class to supplement the current course materials on runaway reactions. The students will use the DCS to simulate a runaway reaction, thereby gaining invaluable knowledge about what types of mishaps will lead to this condition.

Keywords:

Distributed Control System, Modern Manufacturing, Chemical Engineering, Problem Based Learning.