by Greg Simpson

Peek into the future

Is liquid natural gas the answer?

Future Developments
Heavy fuel oil is not an option for future shipping within emission control areas and alternatives have to be introduced. 

Is liquid natural gas the answer?

Kawasaki Heavy Industries (KHI) has completed the development of a large, 9 000 TEU (twenty-foot equivalent unit) container ship fuelled by liquefied natural gas (LNG), and has obtained approval in principle from Det Norske Veritas (DNV). The ship is designed with a new type of LNG tank that provides more space for container cargo.
The LNG is stored in prismatic low pressure insulated tanks (type B). This is the first time such tanks have been proposed for a large container ship. They differ from cylindrical pressure tanks (type C) as they utilise the available space much better due to their prismatic, rectangular shape. 

KHI has adopted a unique technology, the Kawasaki Panel System, for heat insulation in order to reduce the rate of LNG evaporation.

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 the need for cold ironing.

KHI obtained DNV’s 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 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 is currently being studied by the International Maritime Organization (IMO) Sub-Committee on Bulk Liquids and Gases. 

The location of LNG tanks under the accommodation has been a subject of much discussion in the industry and 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, chief operating officer at DNV in an official release.

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

DNV is also promoting LNG, since it is proving to be 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.

Twenty-five ships in Norway are already floating evidence of the safety and technical feasibility of LNG, and DNV has had rules in place for over 10 years.

The new container ship design features: 

• a twin-island design that maximises the cargo space available for loading containers; 
• a two-stroke, dual-fuel main engine that is electronically controlled, with a high combustion efficiency, coupled with a hull form that is optimised to maximise safety and fuel efficiency; and
• an engine that may be equipped with an exhaust gas recirculation system that satisfies IMO Tier-3 requirements for voyages in North American and European ECAs.
KHI will apply the technology and design principles used on other container ships as part of the company’s goal to be a world leader in the development and construction of innovative, eco-friendly vessels. 

With KHI technologies acquired through the past development and construction of LNG carriers, it plans to move into the field of LNG bunkering vessels to further extend the scope of its environmental offerings.

DNV has demonstrated the feasibility of a range of large LNG fuelled ships through concept studies such as the container ship Quantum 9000, Triality (a very-large crude carrier 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.

Per Wiggo Richardsen 

Communication Director DNV

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Issue 2020