When paraffinic hydrocarbons, which may form part of a distillate fuel are cooled, n-paraffines come out of solution by forming wax crystals due to limited solubility of the fluid. The highest temperature at which 20ml fuel, when cooled under defined conditions, will not flow through a 45 micron filter within 60 seconds, is called the cold filter plugging point. It indicates the low temperature operability of fuel without flow improver additives when cooled below the cloud point temperature.

Blending middle distillate fuels with flow improver additives changes the crystalline structure and the coalescence (size) of the n-paraffines. This effect cannot be measured by determining the cloud point. Measurement of the cold filter plugging point is a test more directed to ,,end use" application (clogging of a filter) than to measuring the pour point as a characteristic of the low temperature behavior of fuel oils. 

CFPP - between cloud point and solidification point (pour point) - is not a directly measurable physical quality / performance characteristic. The method is based on reference values obtained from a defined identical test procedure. The CFPP measurement is often combined with the determination of the CP, giving a better control of the base blend. Knowledge of CP temperature permits a reduction of the measurement cycle time by starting the measurement at temperatures that are a few degree above CP.

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Cold filter plugging point analyser 2,09 MB

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