Cold flow improvers

When diesel fuel and heating oils are cooled to temperatures below their cloud points, wax crystals form within the fuel. Without the addition of cold flow additives, these are typically flat rhombic shaped crystals that can cause problems:-

• At temperatures close to the cloud point, fuel system filters in both vehicle and static installations rapidly become blocked.


• At only slightly lower temperatures an interlocking wax crystal structure forms which totally prevents flow within the fuel system (the pour point is reached).

Addition of cold flow additives modifies the size and shape of the wax crystals (below) which:

• Reduces the tendency to block fuel filters and lines.
• Extends the temperature range over which a vehicle can operate (as measured by CFPP and other cold flow performance tests).
• Significantly lowers the fuel pour point.
• Improves fuel handling.
• Offers improved refining economics through upgrading of heavier products to the diesel pool (or kerosene upgrading to jet).

Base fuel wax crystals	Modified wax crystals

Infineum has a wide range of additives, Infineum R series, which have been developed to provide extended cold flow performance across the spectrum of middle distillate fuels. (Infineum also has a range of additives specially designed for use in neat Fatty Acid Methyl Esters, FAME).

If fuels treated with flow improver are stored at temperatures below their cloud points, the modified wax crystals will tend to settle to the bottom of the tank leading to:

• Inconsistent fuel quality.
• Field problems associated with the wax enriched lower portion of the tank.
• Further treatment of flow improver treated fuel with Wax Anti-Settling Additive (WASA) can reduce the size of the wax crystals to the extent that wax settling is significantly slower or is halted completely.

Flow improver treated fuel plus WASA

Infineum has an extensive range of WAS Additives, Infineum R series.

To find a detailed list of cold flow improver additives available to you, please do not hesitate to contact your local sales representative or contact us.