Project Description

In recent years, NCOC experienced failures in the three instrument-air compressors. The issue was associated with the existing protection system based on a stand-alone ABB controller. These controls were installed without the necessary tests and therefore relied on theoretical surge curves and operation.

As a temporary solution, the compressors were operated with vent valves partially open, limiting their maximum capacity.

Eventually, in 2020 a solution was defined: implement surge protection and detection in the current PLCs and disable the old protection system.

Throughout the project, the following tasks were carried out:

• Customization of the Anti-Surge Control (ASC) and Surge Detection (SD) systems.
• Integration of ASC and SD with existing systems for start-up sequences, alarm/shutdown management, event history and data historians (PI).
• Definition of contingency plans in case of sporadic shutdown of any of the other compressors to allow running legacy controls.
• Surge tests to define the actual surge curve.
• Load tests to define operating dynamics.
• Continuous-operation tests to remove the vent-closure limitation.