What precautions and treatment require diesel oil at low temperatures in order to prevent clouding and wax formation?

30 Apr '18, 13:43

April 30, 2018, 1:43 p.m.
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Wax is formulated from paraffin content while fuel kept at a low temperature. It can be liquified again by heating to a temperature greater than the freezing point. The wax ingredient contained in all fuel oil types (HFO, MGO, MDO). Due to recent technological changes in fuel oil refinement, the amount of WAX contained in all fuel oils, including distilled oil, has increased.
The ECA (Emission Control Area) regulation force increased demand in distillate low sulfur oils. A large quantity of distillate oil could be stored onboard in bottom tanks. The bottom tank temperature is affected by the seawater temperature. During the winter season the tank temperature frequently becomes lower than the wax freezing point, resulting in the formation of wax. On the way to the engine it causes filter obstructions.
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To prevent wax formation and protect filters from clogging, following guidelines to be followed.
After receiving a fuel analysis report is received:

  1. Before using the distilled oil, which stored at temperatures lower than the Cold Filter Plugging Point (CFPP) the fuel should be transfer from the storage tank to the Engine room tank (DO settling or service tank) in advance.
  2. Upon completion of the transfer, check the condition of the fuel filter. Closely monitor the filter condition of the fuel transfer pump.
  3. If a WAX obstacle is present inside the fuel filters maintain an oil temperature above the CFPP. If the CFPP is NOT given in the fuel oil analysis report, heat the fuel above the Cloud Point (CP). Note, that the diesel oil temperature should be controlled and not to exceed the highest allowed temperature for the minimum viscosity of the oil required by the engine(s) as per the Maker's instructions.
  4. If the fuel tank is not equipped with a heating arrangement, consider adding Cold Flow Improver (CFI) into the distilled oil.
  5. If a fuel analysis report has not available, but vessel trading in a cold area and suspects high wax content in the fuel the following may be conducted:
    1. Add about 50-100ml of fuel with a thermometer in a clear glass jar.
    2. Place the filled glass jar in a fridge at less than 0.
    3. Measure the temperature at which the fuel becomes cloudy or when wax is deposited. The measured temperature is considered the CFPP, then follow the above described procedure.
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30 Apr '18, 14:06

April 30, 2018, 2:06 p.m.
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