Amarinth delivers advanced centrifugal pump solutions for the Tortue FPSO

Tortue FPSO

Designed to process up to 2.5 million tonnes of liquefied natural gas (LNG) annually, the FPSO had to meet highly complex technical demands. Its construction was carried out by COSCO at its Qidong shipyard in China.

The FPSO will have up to 140 people on board during normal operation with an area equivalent to two football fields and 10-storeys in height.

A key design requirement was the integration of multiple centrifugal pumps, horizontal, vertical, and vertical in-line, for a wide range of topsides and hull applications.

Amarinth was selected to supply 45 pumps, drawing on its extensive experience in designing equipment for FPSOs.

The company's solutions addressed the vessel’s strict space constraints, low Net Positive Suction Head (NPSH) requirements, and demanding durability standards.

Challenges

Integrating pumping systems into an FPSO presents unique engineering and logistical challenges, including:

- Space Constraints: The vessel’s compact design demanded pumps with minimal footprints, particularly in areas with restricted headroom.

- Low NPSH Conditions: Some applications required pumps capable of efficient operation under low NPSH conditions.

- Harsh Marine Environment: Exposure to seawater and other corrosive fluids required corrosion-resistant materials to ensure longevity.

- Complex Logistics: Manufacturing and delivery had to be coordinated across multiple international locations, all while navigating the disruptions caused by the COVID-19 pandemic.

Innovative Solutions

Amarinth deployed advanced engineering and project management strategies to overcome these challenges, delivering customised pump solutions tailored for the Tortue FPSO.

Most of the pumps were designed to API 610 specifications and many were manufactured in nickel aluminium bronze for its durability, resistance to cavitation, corrosion resistance in marine environments, and its non-magnetic and non-sparking properties, ensuring safety, longevity, and reliability in the harsh offshore conditions.

Sea Water Ballast Pumps

To maintain vessel stability as LNG volumes fluctuate within the hull, Amarinth designed bespoke, compact vertical in-line pumps. High-voltage variable speed drives were integrated to enable operation at multiple duty points, accommodating a wide range of pressures and flow rates. This ensured optimal seawater movement in response to both gradual and sudden changes in LNG storage levels and tidal conditions.

The choice of vertical in-line pumps minimised both weight and footprint while still allowing for maintenance within the vessel’s limited headroom. Despite their compact form, each pump stood 4 metres tall, weighed 5 tonnes, and featured a unique double-entry impeller with a 510 mm diameter to achieve the required flow rate. Amarinth also engineered complex pipework to fit seamlessly within the hull’s tight spatial constraints.

Topside Process Pumps

For critical topside processes, including produced water treatment and Monoethylene Glycol (MEG) reclamation, Amarinth supplied pumps designed to handle these highly corrosive fluid featuring Plan 53B seal support systems with double mechanical seals to ensure total fluid containment. Given the vessel’s limited space, Amarinth developed custom baseplates that housed both the pumps and their seal support systems, significantly reducing the overall footprint.

Seawater Lift Duty Pumps

For seawater lift applications, Amarinth provided self-priming pumps powered by substantial MV motors and Plan 53B seal support systems. Given the heavy-duty nature of these motors, Amarinth designed a bespoke support frame that fit the confined hull space while maintaining structural integrity. To further optimise priming efficiency, compact vacuum primer units were incorporated.

Efficient Project Management

The delivery of these pumps had to align precisely with the FPSO’s construction schedule, requiring supply timelines between 37 and 43 weeks. Amarinth implemented a turnkey project management approach, featuring:

- A dedicated UK-based design and manufacturing team.

- Coordinated shipping from the UK to Malaysia and onward to China.

- On-site commissioning engineers at the Chinese shipyard.

- Frequent remote video conferences to navigate the complexities of time differences and avoid unnecessary global travel.

The seamless collaboration between Amarinth, COSCO, and other stakeholders ensured that all pumps were delivered on schedule, keeping the vessel’s construction on track.

Outcomes

Amarinth’s expertise in advanced centrifugal pump design and its ability to navigate complex engineering and logistical challenges resulted in the successful integration of high-performance pumping solutions into the Tortue FPSO. This achievement reinforces Amarinth’s position as a trusted partner in delivering customised, high-quality pumping systems for the demanding offshore oil and gas sector.