Getting on board with a modern DCS solution

02 December 2019

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 a new distributed control system.

In addition to revamping the boilers, pumps and turbines, the project also 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 taked with modernising the turbopumps and turbines automation systems, which traditionally had been managed by separate systems. The replacement of all field instrumentation was also necessary, as it had become obsolete.

The biggest challenge, however, was the short time windows given by the owners to complete the upgrade. 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 thread throughout the project.”

In light of all of this, Leonardo chose Rockwell Automation and its PlantPAx DCS which made it possible to combine all of the control systems in a single platform. Now the central control system for the ships is managed by the Automated Integrated System (AIS), as are the turbines and turbopumps.

Leonardo’s technicians were already familiar with the hardware elements of the PlantPAx solution, meaning that the migration project could be completed without the need for any field rewiring. In collaboration with the Rockwell Automation team, an identical mock-up of the software solution destined for the ships was created on land. This allowed for in-depth functional tests to be undertaken to check that the new system’s functionality was identical to previous levels, making it possible to study possible improvements in the solution and new functionalities with the help of Rockwell Automation specialists.

The land-based inspection phase made it possible to arrive at the commissioning phase with the onboard software operationally ready and it also overcame the problem of working with two ships located in two different shipyards. For the LNG Portovenere, commissioning took place in January 2016 at the Navantia shipyard in Ferrol, while the commissioning of the software on the LNG Lerici took place in 2018 at the Keppel shipyard in Singapore.

The decision to use the PlantPAx DCS also made it possible to include the emergency shutdown system for safe functioning. A remote service line was installed with a satellite internet connection, to deliver continuous support during navigation. It also gave Leonardo the opportunity to offer continuous assistance during operations, along with support for troubleshooting to maintenance personnel.

“Energy consumption has also been reduced thanks to the new generation-control system. Basically, using the PlantPAx DCS, we enjoy double advantages: in addition to progressing from a legacy system to a modern one, today we also have a single system instead of three separate system, with improved performance and speed," said Baccelliere.

Having combined all the systems into a single platform also means having a single supervision and control system – in this case is based on FactoryTalk –  a faster solution in respect to refresh times for the graphic pages and more intuitive for operators.

From an assistance and maintenance standpoint, the ships are now equipped with a remote service system with a satellite internet connection.

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