The key challenges for a pump supplier aboard a FPSO or FLNG vessel include:
Low suction head – lack of headroom between decks means a low suction head is always a significant design consideration. Pumps must be designed to operate in a low NPSH available environment, meeting the specifications whilst not being prone to cavitation which would seriously shorten their working life or ultimately result in catastrophic failure. This requires bespoke design and packaging to fit the available space, meticulous calculations and working closely with the customer to understand the composition of the process fluid and vapour pressures.
Low shear requirements – for the separation processes to work optimally with large volumes of fluid, the mixing of oil and water must be minimized to prevent emulsification. This demands pumps with low-shear capabilities achieved through innovative design of impellers and volutes using the latest computer aided design software.
Water ingress – for applications such as MEG Heating Circulation or Condenser Circulation, the pumps may be positioned on deck with waves washing over them requiring designs with a high level of water ingress protection, including IP66.
Vessel stability – vessels are subject to large fluctuations in loads as they process, store and offload oil and gas. To maintain stability their pumps must move large volumes of sea water into and out of ballast tanks but remain compact enough to fit within just 1m to 4m of headroom.
Despite these challenges, the target time to fit out a vessel is often less than 52 weeks with the time for procurement of equipment as little as 20 weeks. This places immense pressure on the pump manufacturer to align the design and delivery of pumps to meet the critical build schedule as any delay would prove extremely costly. Amarinth has met these challenges supplying pumps to many of Africa’s leading FPSO and FLNG projects.
The Egina FPSO, built by Samsung Heavy Industries of Korea, is positioned in the Egina deep water field 150km off the coast of Nigeria in water depths of up to 1,750m. Amarinth supplied API 610 OH2 super duplex pumps with Plan 53B seal systems for de-sanding and process water treatment packages with many of the pumps delivered on an aggressive 24-week delivery.
Anyala and Madu
Amarinth supplied stainless steel horizontal pumps for the condensate unit in a hazardous zone aboard this FPSO vessel built by Yinson in Malaysia. Moored off the coast of Nigeria it processes oil from the Anyala and Madu field which is estimated to contain 193 million barrels of oil and 18 billion m3 of gas. To meet the project schedules, Amarinth designed, manufactured and delivered the pumps in just 18-weeks.
The Coral South field off the coast of Mozambique is more than 2km beneath the ocean’s surface and contains 450 billion m3 of gas. Amarinth supplied to the FLNG vessel with nine API 610 OH2 pumps with Plan 53B seal support systems for a MEG regeneration unit and four pumps for a desanding unit. The pumps were packaged and designed to operate with low NPSH(A) due to the topside positioning of the skids, were fully IECEx compliant on electrical items, and delivered in just 28-weeks.
Greater Tortue Ahmeyim
Located off the coast of Mauritania and Senegal, this is the deepest offshore project in Africa containing 420 billion cubic meters of natural gas. To maintain the vessel’s equilibrium as the processed LNG in its tanks changed, Amarinth provided compact vertical inline pumps with Variable Speed Drives for the filling and emptying of ballast tanks and designed complex pipework to fit within the space constraints of the vessel. Amarinth also supplied topside process pumps handling highly corrosive fluids and self-priming seawater lift pumps with substantial MV motors and Plan 53B seal support systems.
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