5 Important Points to deal with High Catfines in Fuel.



Global fuel testing Agency, Viswa Lab reports that they have identified very high catfines (102 ppm, 103 ppm, and105ppm) in 3 samples bunkered in the port of Manzanillo, Mexico.

These levels of catfines could cause very serious damage to the machinery. The fuels are out of spec when compared to the ISO 8217:2005 or ISO 8217:2010/2012 standards. Even with purifier efficiency of 80%, the catfine value would be higher than the 15 ppm limit recommended by engine manufacturers. Users should insist on getting catfine values before ordering the fuel. Viswa Lab further encourages users to refer to  analysis reports to improve purifier efficiency for maximum removal of catfines.

What are Catfines?

Catalytic fines are microscopic particulates that remain in marine fuel oil as a result of the crude oil refining process. These  can get embedded into engine components and cause abrasive wear, leading to significant insurance claims.

Viswa Lab’s  Recommendation:

  1. To ensure efficient purification, run two purifiers in parallel, with minimum flow, and keep the HFO inlet at an optimal temperature of 98ºC.
  2. If the vessel is equipped with a conventional purification plant, always ensure that the purifiers are fitted with the appropriate gravity disc corresponding to the actual fuel and the fuel test result.
  3. In order to allow recirculation in settling tanks, purifiers should have sufficient capacity (with extra 10%) to cope with daily fuel consumption. Purifier efficiency tests should be carried out regularly by fuel specialist bodies.
  4. Regular purifier checks  are required by  manufacturer’s service engineers to enhance system efficiency.
  5. Fuel system filters should be regularly inspected and cleaned (not only when high differential alarms are activated). However, if a ship has bunkered “dirty” fuel a few times,  tank cleaning at shorter intervals should be considered. Furthermore, it is recommended that these tanks should have sloping bottoms to prevent the build-up of sediments and cat fines in the bottom.

Source : www.viswalab.com – Technical Updates.


  1. Though mostly neglected, It is very important that settling tank and service tanks are not only drained often but also must be emptied and cleaned routinely during long port stay. Heavier cat fine could be accumulated to dangerous level at the slope bottom, which can be carried along from service tank to engine in bad weather. Whenever analysis result reveal high cat fines, synthetic 5 micron fine hot filter must be used to prevent severe engine damage. High frequency of back wash filter operation also reveal excessive carryover of cat fine along with other impurities.

    • Very well said, Mr. Ali. Most of the cases, we have seen that the sample of oil sent from service tank has high sediment and cat fines, whereas the bunker sample has not many.This means the effectiveness and duration of draining settling and service tanks are not good enough.


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