Environmental Engineering Reference
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COAL Flame
HFO Flame
FIGURE 2.108
Temperature coal flame (degree centigrade).
is consistent with the free jet theory. At that location the velocity measurements are
more accurate. That confirms that the velocity measurements at the first two traverses
in the center of the air jet were not fully representative of the gas phase velocity.
2.5.3.4.5 Burnout
Solid samplings were taken at the chimney and on the coal jet center line. The
burnout level was calculated using the ash tracer technique assuming that the mineral
matter is conserved during the combustion. The burnout is defined as follows:
Ash
Ash
Ash
initial
1-
sample
Burnout =
1 −
initial
Figure 2.111
shows the burnout profile on the center line of the coal jet. The
visible ignition was at ~10 cm from the front wall. No measurements were performed
before the ignition; the first measured port was at 73 cm with a burnout level of
~65%. High burnout level was found at the chimney (99.4%).
This burnout value corresponds to a carbon-in-ash content of 25%. This carbon-
in-ash content is too high for commercial use of the fly ash (less than 5%
carbon-in-ash is required). However, considering the very low ash content of the
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