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Wednesday, September 19, 2018


Since early June several heavy fuel oil samples from bunkerings in the Belfast area have been received with density levels exceeding the limit set in ISO 8217:1996 of 991.0 kg/m3 at 15C. The densities ranged from 994.5 to 1000.8 with an average density of 997.8 for these six deliveries.

Although the Al+Si for these fuels met the ISO 8217:1996 spec (80 mm2/s), the Al+Si for these fuels ranged from 57-65 mm2/s (ave 61 mm2/s). Since the density of these fuels is too high for conventional centrifuges, cleaning capacity will be reduced and fuel entering the engine might not be sufficiently cleaned. If your vessel recently bunkered in this area, please ensure that the fuel quality is known before use.

As these fuels with high density also contained substantial amounts of cat fines, we recommend, for best cleaning action, that the conventional centrifuge(s) should be operated temporarily as clarifier(s). Preferably split the flow between two clarifiers in parallel. The combined flow should be the minimum to meet engine consumption. Also shorten the intervals between bowl discharges since this is the only way to remove water. However, even with these steps we cannot guarantee that the operational efficiency of the centrifuges will be sufficient to adequately remove abrasive particles. Therefore we recommend analysis of samples taken before and after the centrifuges. This may be important to help you avoid serious damage to shipboard machinery.

Source: DNV Petroleum Services