Cathelco has won an order to supply an impressed current cathodic protection (ICCP) system for the Armada Ali which will safeguard the hull of the vessel against corrosion.
The Armada Ali is being converted into an FPSO from the VLCC Osprey, a 301,963 dwt VLCC at the Keppel yard in Singapore. The conversion project is being managed by Bumi Armada Berhad, the Malaysian offshore oil service company who have been contracted for the charter, operation and maintenance of the vessel by Eni Angola S.p.A.
This is the sixth time that Cathelco have supplied equipment for Bumi Armada FPSO conversions, two of the most recent being the Armada Sterling and Armada Claire.
As the Armada Ali has a length of 335 metres it will be installed with a fore and aft ICCP system. Both of the 500 amp systems will consist of a control panel wired to an arrangement of two Cathelco C-Max disc anodes and reference electrodes mounted port and starboard.
C-Max anodes are diver changeable and can be replaced without the need for drydocking. In addition, they provide a high current output from a relatively small surface area and are easily installed using self snapping torque nuts, avoiding the use of torque wrenches.
In operation, the anodes emit a current which flows over the surface of the hull and neutralises corrosive activity. The reference electrodes constantly monitor the electrical potential at the hull/seawater interface and send a signal to the control panel which raises or lowers the electrical output. In this way, the hull receives the optimum level of corrosion protection at all times.
“FPSOs are on station for long periods of time without drydocking and there are clear advantages in having diver changeable anodes which can be changed at sea, if necessary”, said Andrew Gamble who has been closely involved in the project at Cathelco.
Cathelco are also known as world leading manufacturers of marine pipework anti-fouling systems. This equipment is being supplied for the BW Joko Tole, formerly an Aframax tanker, which was converted into an FPSO at the Sembawang shipyard in 2012. It is currently being operated in the TSB gas complex in the East Java Sea by Kangean Energy Indonesia.
Cathelco are providing a pipework anti-fouling system capable of treating flow rates of up to 3,600m3/hr. It will consist of 8 dual purpose copper/aluminium anodes mounted in a strainer which will dose the seawater, preventing the build up of barnacles and mussels which can block pipes and impair the efficiency of downstream equipment.
The anodes are supplied with an electrical current from a control panel and, when in operation, the copper section of the anode produces ions which create an environment where barnacle and mussel larvae do not settle or breed, passing directly to discharge. At the same time, ions from the aluminium section produce an anti-corrosive layer on the internal surfaces of pipes.
The system is completely automatic and requires the minimum of attention from the crew.
Cathelco marine pipework anti-fouling systems are widely used on commercial vessels of every type. In the offshore oil and gas industry, pump protection units are available for oil platforms, semi-submersibles and jack-up rigs. In many instances the units containing the anodes are mounted at the bottom of the pumps, often inside the stilling tube or caisson.