Comment:
Incompatible or unstable fuels can cause severe problems of filter blockage. Polypropylene causes severe filter blockage but no combustion-related problems have been reported.
It cannot be emphasised too strongly that the results are meaningless unless they are from a representative sample.
Below: The Kittiwake Compatibility Tester for residual fuel oils.
Info Centre >> Fuel and Lube Oil Technical Manual >> 4. Fuel Oil - Test Results >> 4.4 Filters
Residual Fuel Systems: Filters
In all residual fuel systems, filters are fitted. These range from simple suction strainers on the transfer pump suction, through to the various designs of cold and hot filters. Maintenance staff can only maintain and clean them according to the manufacturer’s recommendation.
A recently reported problem with marine fuel deliveries has been polypropylene contamination. Hot fuel filters (>120°C) are a weak point in this respect and can become coated (blocked) with partially molten granules of polypropylene. These can often be removed by manually cleaning the filter element.
The Fuel Treatment System
It is recommended that maintenance staff are fully conversant with the design parameters and the manufacturer’s recommendations for operation of the various units in the system. It is against this background that the practical implications of the analysis results can be assessed. This is particularly the case when the results approach or exceed the limits given in the procurement specification. The various characteristics of the fuel as usually tested by routine laboratory analysis are discussed separately.