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Figure 5.13. Cleaning the ash residue, deposited in the combustion chamber –
use the scrapper to clean the ash layer as well as the char particles;
RECOMMENDATION – in order to minimize the risk, it is recommended to
place a metal shovel or an appropriate container, where the ash will be
collected, taking care not to spill the material away. The collected ash and char
residues should be kept in a lid closed container (or any appropriate vessel) and
to be cooled down to ambient temperature level – please consider the safety
first;
The cleaning procedure of the convective heat exchanger of the boiler should be
performed at least once per month, but in practice the operating mode and
mainly the total amount of the fuel consumed should be considered. The practice
show that about 30 to 40% of the ash content of the fuel is transported by the
flue gases to the convective heat exchanger section of the boiler, which leads to
sensible decrease of the heat transfer rate of the flue gases to the circulating
media, i.e. the total efficiency of the boiler will be decreased. However, the fly
ash particles will be transported by the flue gases from the boiler out to the
chimney, so the chimney also collects considerable amount of ash, which should
be cleaned as well. The turbine of the flue gas fan will be deposited with fly ash
and char particles as well. Please note, that the fly ash accumulates in elbows
and other elements of the chimney, as well as the convective duct section of the
boiler will result to increased hydraulic loses of the convecting flue gases,
eventually the duct could be stacked and blocked, which will result in sensible
decrease of the draught of the chimney and even the boiler could emit flue gases
out of the door gaskets as well as other lids. It is highly recommended to clean
