ConocoPhillips is one the largest oil/gas producing companies in the world and the major partner in the Bayu-Undan field, located in Area A of the Timor Gap Zone of Co-operation. Field development includes two central processing platforms for the production and processing of gas to recover condensate and liquefied petroleum gas, which is stored on site in the moored FSO (Floating Storage and Offtake) vessel ‘Liberdade’.
‘Liberdade’ was launched in Korea in September 2002, and is installed at its mooring system at the Bayu-Undan gas-stripping project, 500km northwest of Darwin. The 150,000tonne ‘Liberdade’ is the world’s first combined condensate and liquefied petroleum gas FSO and the largest liquefied petroleum vessel in the world. Permanently moored in a water depth of 80 m. the vessel can store approximately 230,000 cubic metres of condensate and LPG. ‘Liberdade’ processes the condensate and LPG and stores them before shuttle tankers, mooring in tandem condensate) or side by side (LPG) with the FSO, removes the product for delivery to regional markets.
A vast cargo management system controls the movement of the various products between the different processes and storage holds onboard. Hydraulically actuated cargo valves control the flow of product between the vessel storage holds; a critical process when considering the ballasting effect of such large volumes.
Pressure Dynamics were asked to look at upgrading the existing hydraulic system to the nearly 300 cargo valves. The original system was a centralised system with all the hydraulic control valves and Hydraulic Power Unit (HPU) located at the bow. The nature of operation and the shear size of the FSO meant this was a less than ideal configuration, so in consultation with the client it was decided to implement a de-centralised system, placing the HPU below decks in a ‘safe’ area and placing sets of solenoid and other control valves at sixteen various locations around the deck – a nominated ‘hazardous’ area due to the potentially explosive atmosphere.
Not a complicated system by PD’s standards, but the inventory of stainless steel components is impressive, here’s just a few:
Every panel was connected to the in-house PLC controlled test system and all hydraulic and electrical components rigorously tested and certified before despatch, enabling the client to view the full system functionality first-hand, even before installation, and accept the critical-path system with confidence.
The Hydraulic Power Unit was definitely not one out of the box. The client had identified the location for the new HPU to be in a machinery room below decks. The challenge was to design an HPU that could fit through the existing hatches and doorways as part of the installation! Not easy for an HPU that was to be the sole power source for all sixteen valve panels. The answer was modularity – three major sections that could be easily separated, transported & handled, and reconfigured in a confined space.
Once more the engineering department at PD’s rose to the challenge and provided a neat solution that not only overcame the logistics issues, but performed better than the original system!
The requirements for the project included full documented compliance with a broad range of standards for electrical, structural and integrity monitoring, including ASME, Lloyds, CE, DNV & Australian Standards. A big job but the attention to detail by our engineering document control section saw every ‘I’ dotted and ‘T’ crossed. Last count was nearly nine hundred documents and some seven thousand pages!
At the end of the project the result was outstanding – especially when considering the range of ‘constraints’ faced by the engineering team at PD’s. The equipment was worth a picture if just to capture the majesty of tonnes of precisely manufactured 316 stainless steel!
Such an outcome is the result of teamwork, not only within Pressure Dynamics but also with our suppliers. Pressure Dynamics high standards are demanded of our suppliers and this is reflected in the quality and integrity of the systems we produce.