Thermal Oxidizer Control System Upgrade
Our client, a leading global specialty chemical company, operates a chemical manufacturing facility that produces maleic anhydride for use in the manufacture of boats, automobiles, buildings, piping, cosmetics, foods, and beverages.
The plant contains standard chemical manufacturing equipment, including reactors, compressors, pumps, tanks, and a thermal oxidizer.
The existing control system at the plant is a mixture of DCS and PLC control schemes, integrated to allow company personnel to operate and monitor the facility. Because some of the existing equipment was designated “mature” by equipment manufacturers, the client initiated a proactive effort to upgrade controls for the B-800 Thermal Oxidizer.
The control panel for the B-800 Thermal Oxidizer contained a 90-30 PLC with a reported lack of code and variable documentation. The controls and marshalling panels contained a wire termination strategy that desperately required labeling and cleanup. In addition, the control system drawings and P&IDs were not current.
The client called on EN Engineering to increase the reliability of the B-800 Thermal Oxidizer by upgrading the controller to a platform with more capability. An HMI was added locally at the Thermal Oxidizer to display alarms and interlock statuses. The plant was shut down for two weeks for a maintenance turnaround, so the entire Thermal Oxidizer PLC upgrade had to be completed within a short time frame.
Prior to the upgrade, EN Engineering developed a Project Execution Plan (PEP) to provide a documented comprehensive plan for the development and implementation of the B-800 Thermal Oxidizer PLC upgrade project. The two-part PEP addressed the background, objectives, scope and strategies, as well as provided a tactical plan. By following the PEP, the upgrade was completed within the challenging time frame and on budget.
During execution, a ControlLogix PLC was purchased to replace the 90-30, and a new wiring strategy was defined for installation. The existing ladder logic from the 90-30 PLC was rewritten to support the new ControlLogix platform, and a detailed data map was created for interface with the site’s DCS system. As part of installation and commissioning, the 90-30 PLC was replaced with the ControlLogix, the control panel and marshalling panels were rewired using the new strategy, the site drawings were updated as-built, and an exhaustive system test was performed. The entire project installation and cutover was successfully completed within the two-week designated downtime allotment.