DNV approves KHI’s LNG-fuelled boxship

19 Jan 2012
KHI’s gas fuelled container ship design has received approval in principle from DNV

KHI’s gas fuelled container ship design has received approval in principle from DNV

Approval in principle has been granted by DNV to Kawasaki Heavy Industries newly-completed design for a 9,000TEU container ship fuelled by LNG, using a new type of LNG tank that provides more cargo space.

At the same time as class society Bureau Veritas announced its cooperation with DSME on a 14,000TEU LNG-fuelled container ship concept, DNV has unveiled details of a similar project undertaken with Japan’s KHI. The 9,000TEU KHI proposal is 308m length oa, 48.4m beam, with a 14.5m draught.

KHI has obtained DNV approval in principle for both the gas supply system of the vessel and the LNG fuel tanks. Next, KHI plans to perform a safety assessment of the vessel with DNV. The design features a twin-island superstructure to maximise cargo space available for loading containers. It will be powered by a two stroke dual-fuel main engine, which is electronically controlled with high combustion efficiency, coupled with a hull form optimised for safety and fuel efficiency. The engine may be equipped with an exhaust gas recirculation system (EGR) in order to satisfy IMO Tier III requirements for voyages in ECAs. Currently operational ECAs are to be found in the Baltic, North Sea and English Channel, and the North American ECA regulations will be enforced as from August 2012. Other ECAs are under discussions.

In the KHI proposal, 7,000m3 of LNG fuel is stored in prismatic low pressure insulated tanks (type B); according to DNV this is the first time that such tanks have been proposed for a large container ship. They are different from cylindrical pressure tanks (type C) as they make better use of available space due to their prismatic, rectangular shape. KHI has adopted another novel technology, known as the Kawasaki Panel System, for heat insulation in order to reduce the rate of evaporation of LNG.

B-type tanks produce evaporating LNG continuously which must be used for propulsion or auxiliaries. Reefer containers will consume the boil off in port eliminating any emission of LNG to air, as well as eliminating the need for cold ironing.

The LNG fuel tank and diesel oil tanks are located under the forward superstructure minimising the loss of cargo space. The design criteria for ships using LNG as fuel are currently being studied by IMO (BLG). The location of LNG tanks under the accommodation has been a subject for discussion in the industry. DNV plays an active role in these discussions.

“It is important to understand the environmental imperatives that shipowners face, but it is also important to recognise that, in reality, the uptake of new technologies is a balance between risk and business need. Together, DNV and KHI have struck just the right balance with this vessel,” says Tor Svensen, COO at DNV.

DNV states that there are high expectations for LNG as an alternative, next-generation clean fuel to reduce reliance on heavy fuel oil which is currently used for large container ships. LNG was chosen as the fuel for the vessel because it reduces CO2 emissions which contribute to global warming as well as dramatically reducing NOx and sulphur oxides SOx which are major health hazards.

DNV is promoting LNG as an economically favourable emissions reduction solution for shipowners. Decoupled from oil prices due to sources such as shale gas, it is expected to remain competitive for the lifetime of new vessels entering the market. 25 gas-fuelled ships in Norway are helping to prove LNG’s safety and technical feasibility, and DNV has had rules in place for over 10 years.

KHI will apply the technology and design principles used to other container ships as part of the company’s goal to be a leader in the development and construction of innovative eco-friendly vessels. With KHI technologies acquired through the past development and construction of LNG carriers, KHI plans to move into the field of LNG bunkering vessels to further extend the scope of its environmental offerings.

DNV says it has demonstrated the feasibility of a range of large LNG fuelled ships through concept studies such as the container ship Quantum 9000, Triality, a VLCC size oil tanker, and two different sized bulk carriers. “DNV is proud to be working with forward-thinking companies such as KHI to help make clean shipping a reality,” says Svensen.

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