New Era for Tanker Shipping

By Keith Henderson at December 07, 2010 07:43
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Yesterday in London, the DNV classification society unveiled the Triality VLCC concept vessel. So called because of the “tri” or three features of its design: the vessel is fuelled by liquified natural gas (LNG), has a special hull shape that does not require the use of ballast water and virtually eliminates harmful exhaust emissions. A further bonus is its attention to the problem of vapours emitted by the cargo and providing a solution to use them.

Although the vessel introduces new concepts in design, it uses currently available technology and in DNV’s opinion offers an alternative to conventional crude oil tankers using heavy fuel oil that is financially attractive.

The LNG fuel is carried in two separate IMO type C pressure tanks of 13 500 m3 capacity, providing sufficient fuel for 25 000 nautical miles of operation. The tanks are located on deck in front of the superstructure. Electrical generators have a dual fuel capability (LNG and MGO). The cargo oil pumps are steam driven, powered by auxiliary boilers using vapours recovered from the cargo (VOCs).

The new vee shaped hull with revised cargo tank layout dispenses with the use of ballast water in the empty condition: rendering a higher net efficiency for a round trip.

More than 500 tons of cargo vapours can be collected and liquefied during one round trip. These liquefied petroleum gases (LPG) are stored in deck tanks and used as fuel for the steam driven cargo discharge pumps. Unused LPG can be returned to the cargo tanks or delivered to shore during oil cargo discharge.

DNV estimate that the capital cost of their new design will be 10-15 per cent more however the through life cost saving will be 25 per cent less than an equivalent VLCC of conventional design.



The DNV Triality VLCC design
Credit: © DNV/Making Waves


LNG starage gas tanks on board the Triality VLCC
Credit: © DNV/Making Waves


Comments (3) -

Please let me know how is ballast avoided in the light condition.

v.p.kumar |     12/7/2010 8:47:26 PM #

Stability has always been a point of special interest.

Captain Jaap Stengs (Ret.) |     12/8/2010 5:54:18 AM #

Like v.p.kumar I am interested to know how the use of ballast is not needed in light condition. Please give description and drawing.

Captain Jaap Stengs (Ret.) |     12/24/2010 1:23:18 PM #

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