NEWS
Last update: 25 March 1999

NEWS FROM BUNKER WORLD.

POOR IGNITION QUALITY OF BUNKERS PUT ENGINES AT DAMAGE RISK.
Summary from Lloyd's List issued 23 March 1999

Mr. Kjell Augustin a Surveyor of The Protection & Indemnity Swedish Club, warns that an increasing number of claims relevant to main engines damages are caused by the poor ignition quality of Bunkers.
(Notoriously poor ignition quality means ignition delay, or not ignition at all for one or more cycles).
"Ignition delay problems mostly concern medium speed Diesels burning blended fuels of less than 220 cSt", says Mr. Augustin. He believes that specifications for bunkers should include a reference to the Calculated Carbon Aromaticity Index (C CAI). "Yet specifications rarely mention the CCAI, which gives an important range for the ignition quality.
He deems that CCAI is often ignored as there is no widely accepted method for determining its value in residual fuels, although it has been empirica lly established a clear relationship among density, viscosity and ignition performance, thus some oil majors have developed index systems that indicate likely ignition delay.
Mr. Augustin believes that problems appear to be grouped in the CCAI value range of 850-890 (the higher the index number, the longer the delay) and he lists a number of significant malfunctions due to ignition delay:
- fouling of valves, pistons, turbochargers;
- steady deterioration of engine performances in the course of voyage;
- risk of violent combustion producing an explosion that could rip the engine apart;
- ignition delay may lead to violent increase pressure, the known "Diesel knock".
"Owners should not be over influenced by the attitude of charterers. It is worth investing extra care in specifying CCAI values for bunkers, warns Mr. Augustin, the cost of ignoring this issue can be very high".
For the owners operating engines sensitive to low ignition quality fuels, he advises to order fuels with a specified CCAI limit, or set density and viscosity which will control the CCAI.
He suggests some useful precautions in order to reduce the risk of damages:
- the quality of lub oil must be high, in order to cope with the additional load imposed on the bearings;
- keep the engine load within 50%-85% and maintain inlet air temperature as high as possible, with pre-heating prior to start up (ignition delay problems are aggravated in a cool engine)
- tie all bolts (including those of bearings, composite pistons, liners, cylinder heads, etc.)
"special attention is required when a ship is forced to use low viscosity fuels (below 180 cSt) due to heating limitation, if the density is too high - he warns - the CCAI will be also too high and ignition problems may result.

From our side, in addit ion to the precautions expressed above, we suggest also that when a bunker appears to be of poor ignition quality, (usually this deficiency is detected when the ship is already sailed), the Chief Engineer should perform the arrival manoeuvre, after havin g fed the booster fuel oil system with a good Marine Diesel oil, thus enabling him to re-start a relatively cool engine without problem.
We add also that those motor vessels already equipped with Moletron takes advantage of it when poor ignition quality fuels are bunkered.

POLYPROPYLENE CONTAMINATION IN BUNKER F.O. MAY STRIKE ANY MOMENT.
Surprise! From 1997 the shipping industry has learnt to expect a sudden strike from this insidious contaminant, that having a specific gravity (SG) just less then fuel oil SG, escapes centrifuge purification and chokes fine-mesh filters, since particles dimensions range from 30 up to 600-700 microns and easily bind together.
So far, it seems that combustion properties of fuel are not affected by the presence of polypropylene, nor damages to Diesel engines parts (interested by the combustion process of such a fuel) have been noted. In fact polypropylene is a thermoplastic resin made by the polymerization of propylene (also known as methyl ethylene) a colorless unsaturated hydrocarbon gas, a derivative of virgin naphtha, in turn, a crude oil fraction.
However, the burden of too frequent filter cleaning, cases of sudden engine slowdown and power black-out, has led to a large percentage of de-bunkering operations, lost of revenues and legal disputes.
Connections with events of grounding, or collisions due to power or engine's failures are not recorded, yet.
Remedies are not at hand. Studies are in progress to find out a chemical treatment able to dissolve particles of polypropylene aggregation. Clearly, a chemical treatment that has to be compatible with fuel oil features.
Meantime, a ship who decide to pump out a contaminated F.O., needs the help of a large pump unit to speed up the bunker transfer, since her transfer pumps, usually, are not designed to transfer huge quantities of fuel oil, in the tight times allowed by to-day scheduled calls.
Among the bad news, a good one: so far, steam ships seems to have escaped to bunker polypropylene contaminated fuel oil. It could be a statistical reason; or because their hot fuel filters have larger meshes?
The up dating of this topic depends also upon the circulation of news released on the web by good-will operators, who know facts and, in addition to the web, they write on the marine press too.

October 1998.

SULPHUR CONTENT IN BUNKER FUELS.
IMO regulations to curb emissions of sulphur oxides (Sox) from shipping, under a new Annex to Marpol, foresee two limits:
= a 4.5% maximum sulphur content in bunker fuels, as global cap limit for merchant ships;
= a 1.5% maximum sulphur content for fuels to be burnt in designated areas (E.G. the Baltic Sea).
Meantime, EUROPEAN UNION proposals foresee the same 1,5% sulphur content limit for fuels to be burnt in EU territorial waters as well (in addition to the fuel marketed within the EU land). United States are also seeking for more SOx restrictions for their coastal waters at least the same limits in force within land areas. Since the refining industry is not investing in de-sulphuration plants and the low-sulphur fuel is currently obtained by refining low sulphur crude oils, the increasing demand of low sulphur bunker will push skyward the price difference between low-sulphur and high-sulphur content fuels.
Under the pressure of public opinion driven by indisputable environment concerns, the land industry is more and more compelled to burn natural gas and ban the use of fuel oils, because natural gas is free from sulphur, produce less carbon dioxide and less nitrogen oxides. This trend leads refiners to invest in new processes that produce little residual fuel oils (but heavier than previous) or not residual oils at all.
This scenario leaves little hopes to the shipping world that seeks for economic fuels (with low sulphur too).
Along with heavy fuel, ships are already using marine diesel oil, should they use also an intermediate low sulphur fuel when sailing in designated seas? It means to handle a third fuel, provide for additional tanks and piping. Or worse, should they scrub their flue gases and transfer sulphur oxides into coastal waters?
Whereas the adoption of Marpol Annex, EU and USA proposals, sooner or later, shall be converted in laws, ships operators and shipyards are advised to study what remedies can be adopted, on existing vessels, in order to fulfil green rules and contain fuel oil costs.