Comment Log Display

Comments submitted by the International Association of Independent
Tanker Owners (INTERTANKO) and the Oil Companies International
Marine Forum (OCIMF) on CARB regulations


With regard to the California ARB Modified Regulatory Language for
15-day Comment Period on the FUEL SULPHUR AND OTHER OPERATIONAL
REQUIREMENTS FOR OCEAN-GOING VESSELS WITHIN CALIFORNIA WATERS AND
24 NAUTICAL MILES OF THE CALIFORNIA BASELINE, the INTERTANKO and
OCIMF have the following  comments:

1. The majority of the tankers will be significantly affected by
burning marine distillate fuels in the main engines, auxiliary
engines and auxiliary boilers which assume risks and thus require
some substantial and Essential Modifications

A. Main Engine:- the main engines of commercial ships, including
tankers have been designed to utilize marine residual fuel oil with
a kinematic viscosity up to 700 cSt at 50 Celsius degrees and
marine diesel oil specification ISO 8217, DMB grade. The DMB grade
marine diesel oil is defined as distillate with maximum viscosity
of 11.5 cSt and without minimum limit. Those marine diesel oils can
be used, at least theoretically without any problem to the engine
and relevant procedure has also been identified by maker. However,
supply of MDO with a sulphur content < 0.5% is a serious impediment
to ensure compliance by using this fuel type. The alternative given
in the CARB regulation is to use MGO (ISO 8217, DMA grade) of <1.5%
 sulphur content. The specification of the marine gas oil indicates
that the maximum viscosity is 6.0 cSt and the minimum is 1.5 cSt at
40 Celsius. However, direct experience indicate that most of MGO
were bunkered by ships, worldwide were between 2.5 to 3.5 cSt at 40
Celsius or even less than those figures. 

An increase in temperature reduces MGO viscosity which, in turn,
lowers the lubricating properties of the oil. This is detrimental
to the fuel pumps, which rely on the oil as their source of
lubrication for the gear scrolls and is compounded by the fact that
the lower sulphur content of the MGO also reduces the lubricating
properties of the fuel.

The fuel pumps of the main engine have been designed to run when
the marine fuel in use is not less than 2 cSt in order to avoid any
seizure between plunger and barrel and further failure of the
pumps. However, the kinematic viscosity will obviously be lower as
the ambient temperature of the environment on which they are
supplied to the main engine is higher (around 80 Celsius). The
request of use of MGO/DMA grade would require consideration of
alternative measures, such as:

•	segregating the fuel piping system ( dual fuel)
•	extra insulating the piping system
•	cooling the MGO down to appropriate temperature to maintain at
least 2 cSt
•	change to suitable pumping and transferring MGO system

All these issues have feasible technical solutions but require
significant modifications in the engine room. They are time
consuming activities and raises the question on whether the new
equipment which might be required would be available and installed
by July 1st, 2009.

B. Auxiliary Diesel Engines – Same concerns: as above with regard
to the limitation for the fuel pumps.

C. Auxiliary Boilers – The most serious safety concern associated
with the requirement of switching from the HFO to MGO in marine
boilers is the increased risk of furnace explosion in the event of
a flame failure. The increased risk results from two factors, a)
the temperatures created in the furnace during operation and b) the
properties of the MGO.

The ships do use MGO for cold flashing of the boilers which is an
acceptable practice as the furnace temperatures are much lower and
therefore the risks associated with generating fuel vapours and
igniting them is much less. After the initial flashing with MGO,
the boilers are fed with HFO. Although, given time, HFO will also
vaporise, the heavier fractions within in it mean that the process
will take much longer. In addition, the auto ignition temperature
of HFO is higher than that of MGO meaning that the risk of
explosion is much reduced.

Approaching the 24 nautical miles limit from the California
Baseline, ships will be required to comply with this regulation by
switching from HFO back to a much more volatile MGO. The
combination of MGO atomisation through the burner nozzle and the
heat energy residing within the furnace tubes and refractory
materials would cause the fuel to vaporise. This vaporisation can
lead to a highly explosive vapour being present in the furnace.
This can then be ignited from hot spots within the furnace, tubes
and refractory material, by small smouldering ash on the furnace
floor or through incorrect operation of the boiler.  That any of
these may produce an explosion has long been recognised (The UK MCA
‘M’ notice M.1083, reprinted in part in the MCA’s Marine
Information Note accompanying the introduction of this Directive,
MIN 258, states that ‘When using distillate fuels in burners
designed for use mainly with heavier fuels these dangers are
increased and in those conditions steam atomisation should not be
used.’).

During normal operation of the boiler outside of the CARB area the
boiler burner will be adjusted to burn HFO. Changing the boiler to
operate on MGO will affect the flame length by making it shorter as
the MGO will burn faster unless the burner is adjusted at each
changeover. The effect of reducing the flame length is to reduce
the surface area of the flame and therefore its radiant heat. For
boilers operating towards their maximum firing rate such as would
be the case for vessels which discharge cargo by steam turbine
driven pumps this will limit their ability to operate cargo oil
pumps at the maximum rate and therefore slowdown the discharge. The
required adjustment of the burner is not a simple procedure as it
is an iterative process and can take some time to achieve good
combustion of the new fuel.

Manufacturers recommend a number of modifications needed to
minimise the risk when complying with requirements to switch from
HFO to MGO in boilers. Modifications are required beyond the fuel
system (e.g. pumps , steam atomizing system, purging sequence,
flame supervision, software adjustments etc). 

All these modification require time. Many ships calling at
California may not be ready to have all these modifications in
place by July 1, 2009.

2. Availability of MGO

INTERTANKO and OCIMF are concerned with the current approach of
the proposed rule on the availability of marine distillates in the
market. It is hard to understand the logic of imposing by rule
significant non-compliance fees on ships which have to demonstrate
that they genuinely did not manage to find compliant fuel on the
market.

But more worrying is that the proposed rule does not even
guarantee supply of complaint fuel on the Californian ports. The
lack of such a provision may lead to unacceptable situations on
which ships will be considered “non compliant” because they cannot
find the complaint fuel in California. As an example, a ship may
arrive at California with compliant fuel but she would not have
sufficient MGO to leave. In case there is no supply of MGO or low
sulphur MDO in the Californian port, the rule would still consider
the ship “non compliant” and it will impose a financial penalty. 

Our concern is not without substance. A ship had recently called
to California and the crew has investigated the possibility of
bunkering MGO and MDO from a local supplier. The supplier replied
that he will be able to supply MGO only (not MDO) after four
days!!! 

It is the view of INTERTANKO and OCIMF that the State of
California should have shown leadership and, through regulatory
provisions should be prepared to support the proposed regulation in
practical terms. We hope that our comments are seriously considered
by CARB and modifications are made top mandate compliant fuel
supply at any time. Supply of proper fuel is the key element that
would provide ships the ability to meet the proposed regulations.

The consequence of poor and uncertain supply of complaint fuel
world wide would mean that ships, particularly tramp shipping such
as tankers would need to seek supply in different ports and keep
MGO onboard in case they would be required to arrive to California.
This may required modifications for a larger and diversified fuel
storage system. These modifications also take time.