Biomass as Fuel in Small Boilers (PDF 6.4 - APO Asian Productivity ...

Biomass as Fuel in Small Boilers
( ... Continued)
Combustion It is difficult
to maintain
good
combustion
because:
- Air fuel
mixing is not
proper;
- Bed height
is stationary,
resulting
in clinker
formation;
- Avoiding
air channel is
difficult;
- Due to
intermittent
ash removal
system it
is difficult
to maintain
good
combustion.
Moisture High moisture
leads to
bed choking
and difficult
combustion
conditions.
Combustion
is better with
an improved
version of pile
combustion.
Since most
of the fuel
is burned in
suspension,
the heavier
mass falls on
the grate. If
the system
has a moving
grate the ash
is removed on
a continuous
basis and
therefore
the chances
of clinker
formation are
lower.
Combustion
condition not
very much
disturbed
with 4–5 %
increase in
moisture.
- 16 -
It is similar
to stoker
combustion,
but since
the fuel size
is small and
even, the
combustion
efficiency is
improved as
maximum
amount
of fuel is
combusted
during
suspension.
Same as
stoker
combustion.
Best
combustion
takes
place in
comparison
with the
other types
since the fuel
particles are
in fluidized
state and
there is
adequate
mixing of
fuel and air.
It can
handle fuels
with high
moisture
condition up
to 45–50%
but high
moisture
in the
fuels is not
desirable,
and
adequate
precautions
should be
taken in the
design stage
itself.
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