In order to achieve
good combustion, in any type of burner, fuel oil must be heated until it
reaches a viscosity of between 15 and 22 cSt (2.5 – 3.0 ºE) to allow an
adequate degree of atomisation. The temperature of heating may vary between
approximately 80 ºC and 120 ºC, depending on the type of fuel oil
and the burner. These temperatures cause a process of fractioning of the
fuel oil, with the precipitation of a hard black carbon termed ‘coke’,
which tends to become deposited in the outlets of the burners installed in
the combustion chambers of boilers, drying furnaces, rotary dryers, etc.
The droplets from the nozzles, subjected to the reflected heat of the
combustion chambers (especially those of refractory brick), also provoke
the same effect by the evaporation of the most volatile part of the fuel
and carbonisation of the less volatile components (asphaltenes and others).
These processes lead to what
is termed “coking” or carbon build
up of the burner, which is characterised by the progressive obstruction of the atomising nozzle (regardless
of the type of burner installed), causing the following effects:
- Increased production of soot
and increased opacity of the gases emitted
- Increased dripping of fuel
in the combustion chamber
- Diversion of the flame,
directly affecting the refractory walls of the combustion chamber
- Reduction in the flow of the
fuel supply to the burner
- Increased difficulties in
regulating fuel / air / temperature of gases
As may be expected, the final consequences are a reduction in the
energetic yield from the system, increased pollutant emissions,
a reduction in the life of the refractory lining of the furnace and increased
stoppages for cleaning the burner.
These
consequences can be minimised by treating the fuel oil in the storage tank with the
additive “rb bertomeu” beco F2/A, as demonstrated by many facilities
that burn several types of Heavy Fuel Oil (steam boilers, rotary dryers, fluid-bed dryers,
etc).
For
further information on this subject, consult the following documents
compiled by rb bertomeu (by clicking on the chosen title):