Hamworthy’s orders for electric-drive deepwell pumps for FPSOs highlight the success of the electric-driven system challenging the hydraulic pumping system which traditionally has dominated the offshore market.
Shaft transmissions on the 24 Hamworthy electric deepwell pumps supplied to BW Offshore’s Yuum Kak Naab’s are 33m long, making them the longest so far installed on an FPSO. Hamworthy was one of the major sub-suppliers to the conversion of the 360,000 dwt ULCC Berge Enterprise at Sembawang Shipyard in Singapore. Hamworthy’s scope of supply, valued above 60 MNOK, encompassed cargo booster pumps, seawater lift pumps, electric fire pump and diesel fire pump system as well as the 24 electric deepwell pumps for cargo mixing and cargo lifting.
The contract included a full-length pump string-test carried out at Hamworthy’s 30m-high string test tower at the company’s fabrication site in Denmark.
“Electric-driven deepwell cargo pumps offer a reliable, safe and energy-saving alternative to hydraulic-driven pumps, and we offer two types: the cargo-lubricated CL and the oil-lubricated CKL series,” said Stein Thorsager, managing director of Hamworthy’s offshore business. “Both pump types are available for offshore application with particular references to FPSOs and FSOs, and will give oil companies and operators a good and simplified distributed cargo pump system as an alternative to the hydraulic-driven cargo pumps.”
Hamworthy’s offshore specialists have extensive experience in supporting the exploration and production sectors with environmentally friendly, innovative and integrated equipment solutions. “Our electric-driven deepwell pump system with a common control system and independent pumps for each cargo tank gives the maximum flexibility during any operational phase,” Mr Thorsager said. “Using frequency converters means that the pumps can operate at optimum performance during any unloading conditions. This again results in higher total system efficiency and hence lowers the power consumption. Using electric motors directly as the drive force also increases system efficiency compared with alternative systems. Electrical-driven deepwell cargo pump systems require also limited space for the equipment installation.
“The main design features of both CL and CKL pumps have been to improve safety and reliability, increase efficiency and reduce system complexity compared with other systems that are available. The choice between the CL pump’s cargo-lubricated transmission and the oil-lubricated CKL pump is very much up to the operator; the type of crude expected throughout the FPSO’s production life and the maintenance aspects, will be among the determining factors.”
FPSO deepwell pumps featuring electric drives made a breakthrough in 2004 when Hamworthy was selected to supply the cargo handling system for a 900,000-barrel storage capacity FPSO being built by Samsung Heavy Industries, named “Nganhurra”, operating at the Enfield oilfield in Australia for Woodside. Since then Hamworthy’s electric-drive deepwell pumps have been selected for several FPSOs.
