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4.15 Stability and Compatibility
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Stability of Residual Fuel
The stability of a residual fuel may be defined as the ability of the fuel to remain in an unchanged condition despite circumstances that may tend to cause change. Put more simply, it is the resistance of an oil to breakdown. Compatibility is similar in that it is the tendency of fuels to produce deposits when moved.
In the event of a limited stability reserve of a fuel, it is likely that filter blockage will occur. Should there be difficulty in identifying the nature of this material sediment, a small portion should be placed in an open container at a temperature of 60-70°C. A waxy material will melt but an asphaltenic sludge will not. With respect to stability, less than 1% of fuels exceed the ISO specification limit of 0.10%m/m.
Testing for stability or compatibility problems is quite easy and provides a good early warning. Sometimes a marginally unstable fuel can be improved by the use of commercial fuel additives. Once the fuel has chemically broken down, there is no way of satisfactorily reversing the process. If instability is severe, there is little that can be done to improve matters.
The stability of a residual fuel may be defined as the ability of the fuel to remain in an unchanged condition despite circumstances that may tend to cause change. Put more simply, it is the resistance of an oil to breakdown. Compatibility is similar in that it is the tendency of fuels to produce deposits when moved.
In the event of a limited stability reserve of a fuel, it is likely that filter blockage will occur. Should there be difficulty in identifying the nature of this material sediment, a small portion should be placed in an open container at a temperature of 60-70°C. A waxy material will melt but an asphaltenic sludge will not. With respect to stability, less than 1% of fuels exceed the ISO specification limit of 0.10%m/m.
Testing for stability or compatibility problems is quite easy and provides a good early warning. Sometimes a marginally unstable fuel can be improved by the use of commercial fuel additives. Once the fuel has chemically broken down, there is no way of satisfactorily reversing the process. If instability is severe, there is little that can be done to improve matters.
Comment: The effects of unstable fuel cover sludges, blocked filters, overloaded fuel pumps leading to damaged pistons, rings and liners. Stability and compatibility are very similar:
stability - unstable when delivered
compatibility - unstable when mixed at the plant or on board ship. Click to see the Kittiwake Compatibility Tester.
stability - unstable when delivered
compatibility - unstable when mixed at the plant or on board ship. Click to see the Kittiwake Compatibility Tester.
