PROCESS CONTROL
Getting on board with a modern DCS solution Built in 1997, the LNG Portovenere and LNG Lerici are ships designed for the transportation of liquid natural gas. Having reached the middle of their lifespan, the ships needed to undergo a total renovation project including new distributed control systems.
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n addition to revamping the boilers, pumps and turbines, the project included modernisation of all the control systems – from the central management system to the system used for the turbines and turbopumps. The design and implementation of the new automation system was assigned to the Safety Systems and Information Division of Italian company Leonardo. Dedicated to transporting liquid natural gas, the ships, which have a capacity of 65,000m3 each, underwent an extensive refit project, in which Leonardo was involved with automation control, sensors and field instrumentation. At the time of their construction, both the LNG Portovenere and the LNG Lerici were equipped with a Bailey Infi 90 system, which became a legacy system at the end of its lifespan, maintained by the Leonardo service department. The desire to replace the legacy system with a modern, high-performing system was at the heart of the project. In addition to the central system Leonardo was also tasked with modernising the turbopumps and turbine automation systems, which traditionally had been managed by separate systems. The replacement of all field instrumentation was also necessary, as it had become obsolete.
Stoppage time for the ships needed to be as brief as possible. This required good coordination with the other contractors, in order to proceed with installation of the hardware and software in parallel with the revamping of the boilers, turbines, pumps and other equipment – keeping the commissioning phase to a minimum. All internal inspection activities also needed to be scheduled within the upgrade time window. External certification by certifying bodies also had to be factored in as the ships have dual registry: specifically, RINA – Registro Italiano Navale (the Italian Naval Registry) and ABS – the American Bureau of Shipping. “In this context, with so many variables and rigid timetables, selecting the best solution and suppliers was a key factor,” said Stefano Baccelliere, homeland security & critical infrastructure LoB / project
manager at Leonardo. “On the one hand, our time was very restricted, but on the other we wanted take advantage of the occasion offered by these large-scale works to offer our client a solution that was decisively better than the incumbent solution, to allow for possible future developments. “We had to lean towards a solution that did not have hidden surprises. We also wanted a system that had high performance levels associated with the management of functional safety, while also being simple to implement, in terms of hardware and software, ultimately delivering fluid migration of the legacy system to the new system. We could not take for granted the importance of finding a supplier that could bring proven experience from three diverse markets – naval, oil & gas processing, and energy – and above all, one with the capacity to make these vertical skills a common
A big challenge The biggest challenge, however, was the short time windows given by the owners to complete the upgrade.
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November 2019
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