IBIA: very high cat fines levels in northern Europe bunkers rare, incidences decreasing 

IBIA-recommended practices for aluminium and silicon levels in fuel

IBIA executive director Alexander Prokopakis, who, with the input of IBIA’s Technical Working Group, provided the information regarding mean aluminium and silicon levels in ARA region bunker fuel samples, also outlined a series of best practices for vessel operators.

Clean settling and service tanks

"It should be remembered that a proportion of the aluminium and silicon in the delivered fuel will settle out in the storage and settling tanks. As this accumulates at the bottom of the tank over time, it can be disturbed in heavy weather increasing the aluminium and silicon content of fuel passed to the treatment plant. This is why it is important to periodically internally clean the settling and service tanks," Mr Prokopakis said.

The IBIA executive director said that good housekeeping practice would be to have a programme of cleaning these tanks sequentially at drydock or inservice surveys to manage any the build-up of abrasive particles and sludge.

Storage tank cleaning is needed less frequently, typically every five years, he said.

Fuel temperature, time and testing are key to dealing with anomalous bunkers

"There will always be occasional fuel deliveries that can exceed the ISO 8217 limit for aluminium and silicon for HSFO and VLSFO [bunkers], but in most cases, onboard management of the treatment plant such as to ensure correct temperature selection and the use of methods to increase the time the fuel is in the centrifugal separator bowls, [will ensure that] fuels with slightly elevated levels can be generally handled without problem," Mr Prokopakis said.

The IBIA director also recommended routine fuel analysis on short testing turnaround times to monitor vessels’ aluminium and silicon intake and act accordingly if needed.

Mr Prokopakis said operational care and consistency can be equally as important in protecting engine component lifespans as the quality of fuel bunkered.

"Practical analysis shows the efficiency of the centrifuges (separator inlet to separator oil outlet) can vary due to operational circumstances and may not always reach the performance claimed by marketing materials. Careful attention to the temperature of the fuel and operating at a flow rate equivalent to consumption will give the best results. In many cases, incidents of wear caused by cat fines are found to be due to poor operational practices rather then excessive levels of cat fines in the fuel supplied," he said.

On the whole, IBIA said the fuel analysis data shows the number of samples that tested at very high levels for aluminium and silicon "are rare, and the incidence is decreasing rather than increasing". 

A secondary data source has reported fewer than two tests per thousand samples tested show levels of cat fines indicators exceeding 72 mg/kg (the limit on reproducibility of the test ’0.59 times R’).

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