yield of a steam boiler is always related to its ‘energy
efficiency’ and is described in the following formula, assuming we
ignore any possible heat loss through the boiler body (let us presume that
it is very well insulated) :
Heat supplied by the fuel – Heat escaping with flue
Heat supplied by the fuel
This is not to be
confused with the combustion yield, which refers to the relationship
between actual heat produced by combustion and the theoretical
heat supplied by the fuel (NCV).
Therefore, in this type of installation it is desirable to maintain:
- Combustion of optimal
quality in order to gain the optimal yield from the Calorific Value of
the fuel (with a minimal presence of CO and of unburned HC in
- Operation with the lowest possible excess of
air in combustion, to
ensure that the gases are at the highest possible temperature at the
boiler intake (maximum coefficient of heat transmission) and that the
lowest possible exhaust is released into atmosphere (minimising heat
- Heat exchangers free from soot and incrusted
fouling, in order to
prevent any loss in the capacity of heat exchange.
the fuel is from being ‘clean’, the greater the difficulty in maintaining
the above points at optimal levels.Thus, by using natural gas it is relatively easy to achieve optimal
levels, whereas the use of heavy fuel oil is a hindrance in this respect,
and requires intensive cleaning maintenance on the installation to prevent
a loss of production capacity or an increase in heat loss via the exhaust
gases released into the atmosphere.
additives for heavy fuel oil, light fuel oil and Diesel oil such as the various types produced by “rb bertomeu”,
are designed to act simultaneously on the three key points by favouring and improving combustion with a low
level of excess air, while altering the melting point of ashes, so that
they are flakier, less adherents and more powdery. This helps to obtain
maximal production with a saving in fuel of up to 8 %.
For further information on this subject, consult the following
documents compiled by rb bertomeu (by clicking on the chosen title):
· Encrustations in fuel oil steam boilers
· “rb bertomeu” products and its aplications.
Dossier rb – Customer reference letters