PureBallast, Alfa Laval’s chemical-free system for ballast water treatment developed in cooperation with Wallenius Water, will be installed aboard two new bitumen tankers for Nynas, a word-leading supplier of specialty petroleum products.
It is the first ballast water treatment installation adapted to the hazardous tanker environment. Nynas, a specialist in naphthenic oils and one of Europe’s leading suppliers of bitumen, has chosen Pure Ballast for two bitumen tankers to be built at China’s Wuhan Nanhua Huanggang Jiangbei Shipyard. Scheduled for delivery in 2010, the Nynas vessels will each have a ballast tank capacity of 2150 m3 and a treatment system flow of 500 m3/h. But in light of their cargo and the resulting gas risks on board, the vessels will have their PureBallast systems above deck rather than below. The ballast water treatment solution, which involves a specially designed enclosure, is the first to be certified for use aboard petroleum tankers. Since the new tankers will operate in sensitive areas like the Baltic and North Seas, the selection of a ballast water treatment system was an important issue for Nynas. In addition, Nynas chose to analyze the pending IMO requirements, including the possibility of ballast water exchange. Ballast water exchange can allow new builds to avoid treatment during the first years of operation, but it did not seem a feasible option for Nynas.
Even after Nynas had chosen PureBallast, the system had to be adapted to the hazardous environment of a bitumen tanker. As well as releasing gases, bitumen is normally transported at a temperature between 160-180°C but vessels can carry products up to a temperature of 250°C. Such conditions have thus far prevented ballast water treatment on tankers, since no ballast water treatment system has yet been classified as EX-proof.
The finished design for the Nynas tankers places PureBallast in a pressurized structure on deck, rather than in the engine room. With a double-door construction that acts as an airlock and an over pressurised ventilation system, the housing eliminates the need for an EX-proof treatment system, allowing PureBallast to be certified by Bureau Veritas for use in this environment.
In addition, the order brings the total number of PureBallast installations to around 60. PureBallast has been selected by over a dozen shipping companies, including large global players like Wallenius and E.R. Schiffahrt. Moreover, PureBallast has been chosen for a wide variety of vessels, ranging from RoRo and supply vessels to container ships and bulk carriers in capacities from 250 to 1000 m3/h.
