How aware are you of the potential for wax to precipitate from your VLSFO Fuel?

The introduction of Very Low Sulphur Fuels (VLSFOs) back in 2020, brought a more paraffinic fuel type to the market and with this fuel, came greater concerns relating to their poorer cold-flow properties.

Unlike the clear and bright marine gas oils, who utilize cloud point, cold-filter plugging point and pour point to monitor their cold-flow properties, VLSFOs as a dark fuel could not use the standard cloud point test, yet measuring this parameter in VLSFOs was a key requirement for VLSFOs.

To aid trouble-free operation in terms of storage and transfer of “dark” fuels, VPS developed a unique, proprietary test method capable of accurately determining the Wax Appearance Temperature (WAT) and Wax Disappearance Temperature (WDT)

For dark fuels, measuring the cloud point, or WAT, is a key operational benefit, as knowing the temperature at which wax will precipitate from a fuel, will enable the correct storage and transfer temperatures to be set. This will avoid filter and pipework blockages, purifier blockage and fuel injector issues.

In addition, the test also determines, the WDT. This is the temperature at which wax will once again become molten and return to the fuel solution, following precipitation, with this temperature at a higher level than the WAT.