Low-Sulfur Fuel Could Increase Engine Damage



Machinery damage is by far the most frequent cause of loss in marine insurance and the numbers are likely to increase with the introduction of low-sulphur limits.

Historically, 40% of hull claims by number are machinery damage, and they make up for 20% of costs.

The most typical and well-known contaminant that can destroy an engine in a short time is cat fines. Cat fines are an inevitable byproduct of refining and consist of small particles of metal that are deliberately introduced to ‘crack’ the fuel. Unless removed by purification, cat fines will become embedded in engine parts and cause serious and rapid engine damage. Filtration of fuel has been a requirement on board for many years, but crews are now noticeably less experienced and less reliable in operating the systems. The level of cat fines is also likely to increase with the introduction of new low sulphur regulations, which will require more refining. 

Read an Interesting Case Study – Fuel Changeover Caused Engine Failure

Most of the times vessel operators and crew neither have any clue about the purity of the fuel they use nor have any compulsion to find out about the purity before using it. Often the purifiers installed are inefficient and cannot cope. There are many reported cases where filters needed to be removed or by-passed. Engines need fuel with no more than 15 ppm, whereas fuel is produced at 60ppm and over*. There clearly is a need for more crew training and somebody to verify that the equipment and systems installed remove the cat fines on their way to the engine.

Low sulphur fuels are less lubricating and this combined with the introduction of increased amounts of abrasive materials results in damage to the engine. Once cat fines become embedded in engine parts, they cannot be removed. Until, fairly recently, such losses have simply been described as engine damage or crew negligence and the real cause never came to light. It is only now that attributable losses are being reported.

Claims due to cat fines have been identified in the range of USD 300,000 to USD 1.5m, mostly in low-speed engines.

Wear is very rapid.

For example, if liners are replaced they could be worn out again in three days. In a technical paper presented at the CIMAC Congress in 2013, cat fines were found in 84% of all the cylinder liner high wear cases investigated.

Contributory changes that would help:

  1. Sampling and testing of fuel before use
  2. Improved fuel handling on board 
  3. Improve the quality of bunkers 
  4. Alter the ISO standard
  5. Charter/bunkering contracts should specify fuel less than 60ppm
  6. Regular cleaning of filters, frequent drainage
  7. Clean the settling and service tanks during dry dock
  8. Check centrifuge capacity on specifications for new buildings
  9. Ensuring optimized fuel system treatment
  10. Introducing a new fuel cleaning system layout
  11. Automatic control of the cleaning flow rate
  12. Intensified monitoring of the fuel treatment efficiency

Furthermore, recent statistics from the California Department of Fish and Wildlife show that switchovers between heavy fuel oils and distillate fuels, just to comply with the lower 0.1% sulphur limit in the Californian ECA, increase the risk of vessels losing power. The risks related to the complex switch-over will have to be carefully monitored, and proper crew training and awareness is needed. 

Nevertheless 1st of January, 2016 is the implementation date of the 0.1% sulphur content limit for marine fuel on vessels operating in the North American Emission Control Area. The U.S. Environmental Protection Agency (EPA) and the U.S. Coast Guard are ramping up their inspection and enforcement efforts to monitor compliance.

The 0.1% sulphur limit also became mandatory in the northern European Emission Control Areas (ECAs) as of 1st January 2015. The European Commission has proposed that at least 10% of vessels calling in European ports are monitored for compliance, with results being made public. From the coming year, 2016 onwards, up to 40% of vessels inspected will have their fuel sampled. No escalation of incidents or specific challenges reported so far from the new northern ECA limits. 

Ultra Low Sulphur Fuel Oil (ULFSO):

The main challenges with the new ULFSO are: Cold flow properties (heating required), stability (limited experience) and compatibility (increased storage capacity and separation requirements, and higher demands for tank cleaning between bunkering due to the variation in fuel quality). The International Council on Combustion Engines (CIMAC) published in June 2015, a position paper on these new fuels. The paper includes some key technical considerations for shipowners and operators. CIMAC has also initiated a working group with technical experts from the industry to address the limited experience and collate information in order to develop a technical guide for these fuels.  

In November 2015, the U.S. Coast Guard confirmed several reports stating that main engines may not attain the expected speed when using ultra low sulphur fuel oil. Consequently, the Coast Guard revised its list of recommendations to vessel owners and operators about the importance of establishing effective fuel oil changeover procedures to comply with MARPOL Annex VI emission regulations.

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Source: IUMI – International Union of Marine Insurance.


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