High anxiety in the shipping
industry about "Low Sulphur Fuel"
With just several months
left before the IMO Marpol 73/78 Annex VI comes into force in 2005, many ship
owners and ship operators are still grappling with the technical implications of
the fuel sulphur regulations.
The key question is
whether commercial vessels with their existing engine and tank configurations
are prepared to consume bunkers with lower sulphur content, particularly when
they enter the so-called Sulphur Emission Control Areas (SECAs).
Ship owners and
ship operators should first be aware of the differences between heavy fuel
oils (HFO) and ‘distillates’ such as marine diesel oils (MDO) and marine gas
Unlike distillate fuels,
HFO requires heating before being injected into diesel engines or
boilers, due of their high viscosities.
The latest statistics
indicate that world average sulphur levels in residual fuels is about 2.6%, but
in some areas, fuels with a sulphur content of up to 4.5% are common. Such fuels
may be termed high sulphur fuels (HSF). Most engine manufacturers and lube
oil suppliers describe low sulphur fuels (LSF) as products containing less than
1% sulphur, although some may include sulphur levels of up to 1.5%.
ISO 8217 specifications currently limit sulphur content to
1.5% for MGO and 2% for MDO as well as blended diesel oils, while statistics suggest that actual average
sulphur content for all distillate fuels is about 0.6%.
The EU directive,
however, is proposing that ships at berth in some areas consume LSF with a
maximum of 0.2% sulphur. From 2008, this limit may be
lowered to 0,1%.
In the absence of an
international definition for marine fuels with 0.2% sulphur or less, we will
call such fuels Ultra Low Sulphur Fuels (ULSF).
The bunker industry,
presently, has little or no knowledge about the characteristics of LSF
and ULSF, both of which are not yet readily available in the market place. This
could be a major problem for marine fuel refiners as they will soon face
mounting pressure to meet the increased demand for low sulphur products,
presumably by introducing new production processes.
designed to operate all their marine engines on HFO, will also face numerous
technical challenges when consuming LSF and ULSF; especially during the
change-over from HFO to LSF or ULSF and vice versa.
To begin with, HFO and
fuels with low sulphur content may be incompatible in certain blending ratios.
During the change-over from HSF to LSF/ULSF, and vice versa, distillate
components may disturb the stability of the HFO and cause asphaltenic sludge to
precipitate. In the worst cases, the engine hot filters will be choked, causing
fuel starvation and other ill consequences for the ship.
LSF and ULSF used in
combination with cylinder lubricating oils with high Base Number (BN) may also
result in over-lubrication, leading to cylinder liner lacquering and scuffing.
On the other hand,
some ULSF do not provide sufficient lubricity to high-pressure fuel pumps for
problem-free operation. Those high in aromaticity often have poor ignition and
combustion properties, possibly due to the de-sulphurising processes in the
refineries having a negative impact on the properties of the fuels' blended
Last but not least, the
existing tank capacity and pipelines designs on many ships make segregation of
HSF and LSF difficult or even impossible.
While two-stroke marine
diesel engines may be able to consume LSF for short periods, long-term LSF
operation can be problematic and thus raise safety concerns, particularly
when the vessels are sailing in congested waters or in the SECAs.
To what extent two-stroke
main engines will have to consume ULSF remains to be seen, since the regulations
are still unclear about the restrictions in SECAs and inland waterways in the
EU. Most likely, the
consumption of ULSF ‘at berth’ as mentioned in the regulations should imply
mainly the use of auxiliary engines to power winches, cargo pumps and
So how to prepare
for the low sulphur regulations ?
The IMO and EU
regulations are unfortunately not in line with each other on how SOx emissions
can be reduced. As an
alternative to burning low sulphur fuels, the IMO permits the use of approved
after-treatment exhaust gas cleaning systems or other technologies that can be
verified to limit SOx emissions.
The EU directive, in its
present edition, is less flexible and only allows fuels with maximum 1.5%
sulphur to be used in restricted areas.
Hence, if exhaust gas
cleaning is not going to be a viable alternative in the EU, ship operators must
equip their vessels with more segregated units of bunker tanks, settling tanks,
service tanks and cylinder lubricant tanks. Tank layout and design should
ideally be planned during the new building process since modifications on
existing installations can be costly. Even so, ships have this option to
reconfigure their onboard fuel treatment plants.
For the vessel’s chief
engineer, the best way to detect possible problems is to frequently check the
condition of the main engine piston crown and to inspect the piston ring pack
through the scavenge air ports. Over-lubrication should generally
be avoided, but in practice, this may not be a safe practice because engine
tolerances are small.
Moreover, when ships according to
the proposed EU regulations consume LSF in the SECAs, they could be sailing in
narrow straits, channels and passages, where engine failure is potentially
disastrous. In this regard, two-stroke engines should preferably use a cylinder
lubricant with reduced BN. During prolonged LSF operation or
if ULSF consumption is unavoidable, the chief engineer should seek relevant
advice from the vessel’s engine builder and the lubricant supplier.
companies(FOBAS) can also help ships cope with low sulphur fuels.
As the Marpol Annex VI
regulations will be in force as of May
19th 2005 large ship
operators preparing their vessels for low sulphur fuel consumption will have to
make many important decisions quickly.
Among the considerations,
they will have to assess the necessary modification to current tank arrangements
for segregating HSF from LSF.
Ship operators should
also know which type of low TBN cylinder oil is most suitable for their vessels’
LSF and ULSF operation. They will need to source for
reliable suppliers of low TBN cylinder oils and determine whether adequate
amounts of these products can be kept on board to replace high BN cylinder oil
High sulphur content
fuels require cylinder oils with a high TBN (Total Base Number). High
sulphur fuels generate sulphur oxides during the combustion process which
when combined with water, also formed during combustion, can cause
corrosive sulphuric acid. The alkaline additives in high TBN cylinder oils
neutralize the corrosive acids generated during the combustion process.
Accordingly, low sulphur fuels would need a cylinder oil with a lower
Typically your low sulphur fuel oils are gas oils or diesel
oils which are "lighter" oils with lower viscosities and consequently
lower lubricating qualities when compared to heavy fuel oil (HFO). All
slow and most medium speed disel engines are designed to operate on HFO.
If running-in an engine on a lighter fuel, more time would be required to
wear in the cylinder liner and piston
Finally, ship owners and
ship operators must ensure that their chief engineers are comfortable with the
change-over procedures for distillate fuel operation, and that the ship crews
can monitor cylinder liner condition effectively.
-Marpol Annex VI- IMO Assembly Resolution A.719(17)
From May 19th 2005 all sea going vessels above 400 GT are required
to take samples during bunkering operations, this in conjunction with Air
Pollution Marpol Annex VI. The samples are to be stored on board the vessel for
a period of 1 year. Vessels trading in SOx Emmision Control Areas (SECAs) will be required to produce an
"International Air Pollution Prevention Certicicate". The Baltic Sea will fall
under a SEC Area. Other SECAs will follow in the future.
Requirements for control of emmisions from
ships; Link IMO
Ozone depleting substances
Prohibited ..... except new
installations containing HCFCs (Hydrochlorofluorocarbons) are permitted
until January 1st 2020
Each diesel engine with an output power of 130KW which is installed on
a ship constructed on or after January 1st 2000
Sulphur content of any fuel oil used on board ships shall not exceed
4,5% m/m, in SEC Areas 1,5% m/m
The above will be enforced by Port State Controlling Officers under the
Protocol of 1997.
On 99% of vessels the above values will be reached using low sulphur fuel
Diplomatic Conference on the Revision of the SUA Treaties: 10-14
October 2005 Amendments to the Convention for the Suppression of Unlawful Acts
Against the Safety of Maritime Navigation, 1988 and its related Protocol, which
provide the legal basis for action to be taken against persons committing
unlawful acts against ships (and against fixed platforms located on the
continental shelf) are set to be adopted by the Diplomatic Conference on the
Revision of the SUA Treaties, which meets from 10 to 14 October 2005 at the
London headquarters of the International Maritime Organization (IMO), the United
Nations specialised agency responsible for safety and security of shipping and
the prevention of marine pollution by ships.
The principal purpose of the SUA treaties is to ensure that anyone
committing unlawful acts against the safety of navigation will not be given
shelter in any country but will either be prosecuted or extradited to a State
where they will stand trial. Among the unlawful acts covered by the SUA
Convention are the seizure of ships by force; acts of violence against persons
on board ships; and the placing of devices on board a ship which are likely to
destroy or damage it.
The two draft protocols to amend the 1988 treaties were developed
by IMO's Legal Committee and are aimed at ensuring that the legal framework put
in place by IMO continues to provide an adequate basis for the arrest,
detention, extradition and punishment of terrorists acting against shipping or
fixed platforms or when using ships to perpetrate acts of terrorism. The draft
protocols broaden the list of offences covered by the treaties and introduce
novel provisions to facilitate the boarding of ships where those offences may
already be in the process of being committed, with the aim of preventing or
neutralizing their potentially damaging consequences.
Work on the revision of the SUA treaties follows from the
adoption, in 2001, of IMO Assembly resolution A.924(22), which called for a
review of the then existing measures and procedures to prevent acts of terrorism
which threaten the security of passengers and crews an the safety of ships.