In Control: How to Implement Distributed Control During a Plant Revamp
Keeping in view the limitation of old instrumentation vis-à-vis benefits of the latest systems, specific special provisions were made during finalization of the technical specifications of the entire system such as high fail safety, redundancy and optimization of complex control loops.
Since upgrading a DCS can be a monumental and expensive project, it was important to evaluate whether it makes more sense to migrate the entire system at once or conduct a partial or phased approach, which most DCS suppliers offer. A phased upgrade can minimize the downtime, be less risky and the cost can be spread out.
Upgradation of DCS
Most of the new versions of DCS can be configured on top of the legacy control systems. This can be done on a running plant with no impact to production. By upgrading the DCS, you ensure that operators know the new technology before the complete system is installed. Changes in presentation and interaction with new controls are some of the biggest hurdles that operators face.
Many new DCS packages also support extra connectivity, such as OPC. In view of the above limitations, it was planned to migrate from a conventional pneumatic instrumentation and process control system to the latest state-of-the art DCS along with microprocessor based smart field devices to run the plant without shuting down which was a challenge.
A Team of Specialists is on The Task
A cross functional team (CFT) of process, instrumentation and electrical engineers was formed to successfully complete the project in phase manner in mid 2012. This team did a marathon exercise that included consolidating and studying old drawings and P&IDs, interviewing plant operators, deciding the operational philosophy, preparing wiring connections and JB details, etc.