Common Heavy Fuel Oil Contaminants
As we have seen heavy fuel oil is a by-product of crude refining and is really the dregs of the atmospheric distilling column, sinking to the bottom of the column after all the other fuels have been drawn off.
The heavy fuel oil therefore contains numerous contaminants removed remaining in the crude and from the distillation of the other fractions. These are as follows:
These are soluble elements of nitrogen and sulfur.
The sulphur causes rapid wear in the engine due to its acidity, and produces sulphur oxides on combustion. The acidity is controlled by additives of organic compounds.
However, the latest IMO emission regulations will require additional post-combustion treatment or the introduction of a scrubber in the exhaust gas ducting such as currently used in shoreside power plants.
Nitrogen oxides in the combustion exhaust gases are controlled by maintaining optimum temperature, pressure, and viscosity of the heavy fuel oil as it is supplied to the fuel injectors.
Exhaust emissions of CO2 and CO are controlled somewhat by the correct amount and temperature of the combustion air supplied by the turbo-blowers. At present there are no emission regulations for these pollutants.
There are normally only traces of these metals in the HFO, however the addition of organic compounds can lessen their effects.
In the next article we shall examine the measures taken to ensure the most efficient combustion of the heavy fuel oil, with the least production of air pollutants.
alkenmurray - additives to HFO to mitigate contaminates
bakerhughes - additives to HFO to mitigate contaminates