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Friday, September 21, 2018


High density fuel in Singapore

DNV Petroleum Services has received five consecutive IFO 380 samples from one of the small Singapore suppliers which significantly exceeded the density specification. The five samples were substantially identical in quality with a density of 997 kg/m3, viscosity of 300 mm2/s @ 50 Deg.C, and Al+Si of 67 mg/kg. This suggests the problem may be limited to a single cargo. Although the scope of the problem appears limited at this time, we advise caution. Therefore if your vessel recently bunkered in this area, please ensure that the fuel quality is known before use.

Although the Al+Si for the five samples met the ISO 8217:1996 spec (80 mg/kg), the Al+Si for these fuels ranged from 64 to 70 mg/kg (ave 67 mg/kg). Since the density of these fuels is too high for conventional centrifuges, cleaning capacity will be reduced and the fuel entering the engine might not be sufficiently cleaned.

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 with the flow split between two clarifiers in parallel. The combined flow should be the minimum to meet engine consumption. Intervals between bowl discharges should be shortened 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