DNV GL’s Guidelines for Fuel-Sulphur Cap Compliance

Winds of Capital Change

Nothing is permanent except change. Managing change can be tricky business though. Come January 1, 2015, and ships plying in Emission Control Areas (ECAs) can use fuel with maximum 0.1% sulphur by mass.

Emission Control Areas

(Source: http://www.bcshippingnews.com/shipping/air-emissions-meeting-challenge)

Sulphur causes acid rains and respiratory disorders. The said cap is in order and in accordance with Annex VI of the IMO’s International Convention for the Prevention of Pollution from Ships (MARPOL).

At present, the most viable option for ships to comply with this threshold is to use Marine Gas Oil (MGO) instead of the present Heavy Fuel Oil (HFO). An inappropriate transition can propel operating costs and expose equipment to avoidable hazards.

In a fresh publication titled Sulphur Limits 2015 – Guidelines to Ensure Compliance, world’s leading ship and offshore classification society DNV GL has come up with guidelines to ensure a smooth changeover to the low sulphur era.

DNV GL has also come up with a customizable Fuel Change-Over (FCO) Calculator. The FCO is a software based on complex numerical simulations that enables ship operators better estimate the ideal parameters during the shift.  

Guidelines for Seamless Transition

Emission Control Areas (ECAs) are oceanic regions with strict caps on the emissions of sulphur oxides (SO_X), nitrogen oxides (NO_X), and particulate matter from ships plying in them. Annex VI of MARPOL deals with prevention of air pollution by ships in ECAs.

Sulphur & Nitrogen Oxides cause Acid Rain

(Source: http://biology.tutorvista.com/environmental-pollution/air-pollution.html) 

Annex VI identifies four ECAs:

·         North American

·         U.S.-Caribbean

·         Baltic Sea

·         North Sea

Annex VI of MARPOL gradually lowered the fuel-sulphur cap in ECAs to:

·         1.5% before July 1, 2010

·         1% after July 1, 2010

·         0.1% from January 1, 2015

Most ships will use HFO while plying in non-ECA regions and switch over to MGO when in ECAs. During the transition to MGO before entering an ECA, the residual HFO in the ship’s service system will be continuously diluted by MGO and the time taken by the mixed fuel to reach 0.1% or less sulphur will vary and depend on:

·         volume of the service system

·         fuel consumption

·         sulphur percentage in HFO

Service System comprises of the lines that supply fuel to and return fuel from the main engine(s), auxiliary engine(s), and their subsidiary components. In view of the protracted dilution / replacement process, ship operators will need to take note of the following parameters:

·         Operating Temperatures of the two fuels varies by 100-120⁰C and improper fuel replacement can trigger thermal shock i.e. sudden expansion or contraction that can lead to seizure of pump plungers

Any change of over 2⁰C/min induces the thermal shock. Managing the changeover requires gradual reduction of load and of the operating temperature difference between fuels

·         Mixing the two fuels in storage tanks may cause the contaminated MGO to contain over 0.1% sulphur and attract regulatory penalties

·         HFO-MGO Fuel Mismatch can block filters and shut off engines

·         Viscosities of the two fuels are different and may cause leakages and pump failures

·         Cylinder Lubrication as sulphur increases the acidity of fuel. Cylinder lubricants contain proportionate alkalis to neutralize the acids. Using low sulphur fuels requires a switch to low-alkaline lubricants to prevent engine damage and erosion

·         Flashpoint can be an issue for the IMO prohibits the use of fuels with flashpoint below 60⁰C to minimize the risk of onboard explosions. Numerous ultra-low sulphur fuels however have flashpoints below 60⁰C. Selecting the correct gas fuel is of critical importance

DNV GL’s FCO Calculator uses vessel-specific data on fuel prices, fuel system layout, temperature constraints, return flow systems, and endless changes in the fuel consumption, fuel-sulphur content, and fuel temperature to compute the following related to the changeover:

·         optimum time

·         maximum allowable hourly fuel consumption

·         required quantity of MGO

Similar Efforts & Bodies

Sulphur Directive 1999/32/EC (as amended by Directive 2012/33/EU) has allowed ships berthed at all European ports, within and outside ECAs, for over two hours to use fuel with maximum 0.1% sulphur from January 1, 2010. The directive does not apply to ships that turn off their engines and use shore power when berthed.

Fuel-Sulphur Caps: In ECAs and at the Global Level

(Source: http://www.axces.eu/index.php?option=com_content&view=article&id=308:sox-sulfur-content-of-fuel&catid=141&Itemid=580)   

Under the Regulated California Waters regulation, vessels within 24 nautical miles of the Californian coastline cannot use fuel with over 0.1% sulphur for their main engine(s), auxiliary engine(s), and auxiliary boiler(s) from January 1, 2014.

European Sustainable Shipping Forum (ESSF) is a body established by the European Commission (EC) to bring together all the stakeholders to ensure smooth implementation of the 0.1% fuel-sulphur cap guideline from January 1, 2015.

Finally

DNV GL’s suggestions have just made managing change a lot less tricky. This is of course the start of a long drawn out process of change that will culminate in 2020 or 2025 when Annex VI will cap fuel-sulphur at 0.5% across the globe.