The approaching 1 January 2016 deadline for enforcement of IMO (International Maritime Organization) developed Tier III emission controls, governing NOx emissions from ship fuel in Emission Control Areas (ECAs), has led to the development by IHI Marine United Inc. (IHIMU), of a low-emission containership that can run on liquefied natural gas (LNG) in addition to the conventional fuel of heavy oil. A concept design has now been completed for a 10,000 TEU* large container vessel.
For this purpose IHIMU has developed proprietary technology SPB (Self-supporting Prismatic Shape IMO Type B) LNG tanks, which have the following features:
- The SPB fuel tank does not cause sloshing of the liquid and is suitable for use as a fuel tank of a ship exposed to the waves.
- The fuel tank geometry is without constraint and can efficiently utilise the available space in a complex ship design.
- Lightweight material is used.
- As a result, when compared to heavy fuel oil, an LNG fuel system can be achieved with minimal reduction in cargo volume.
In addition, the SPB LNG fuel tank has already acquired basic approval (AIP) as a marine application fuel tank from American Bureau of Shipping (ABS).
IHIMU says it fully supports the increased regulation of emissions and will be incorporating the SPB LNG fuel tank system into designs of other vessel types for shipping companies.
Tier III (from DNV)
Ships constructed on or after 1 January 2016 will have additional limitations when operating in an Emission Control Area.
For Tier III ships operating in the NOx ECAs, the allowable NOx emissions are:
- 3.4g/kWh when n is less than 130 rpm
- 9.0*n(-0.2) g/kWh when n is 130 rpm or more but less than 2000 rpm
- 2.0 g/kWh when n is 2000 rpm or more
It should be noted that the Tier III limits cannot be achieved without additional means, such as Selective Catalytic Reduction (SCR) and Water Injection.
Existing Emission Control Areas include:
- Baltic Sea (SOx, adopted: 1997 / entered into force: 2005)
- North Sea (SOx, 2005/2006)
- North American ECA, including most of US and Canadian coast (NOx & SOx, 2010/2012).
- US Caribbean ECA, including Puerto Rico and the US Virgin Islands (NOx & SOx, 2011/2014).
DNV says it is likely the Baltic and North Sea will also be declared NOx ECAs ahead of 1 January 2016.
* TEU: Twenty-Foot Equivalent Units (intermodal shipping container)
(This article primarily compiled using information from an IHI Marine United Inc. press release)