October%202006

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October 2006
UNIVERSITY OF BUCHAREST, FACULTY OF POWER
ENGINEERING

• ROYAL INSTITUTE OF TECHNOLOGY (KTH)

INVETIGATIONS OF POTENTIALITIES OF BIOMASS
PYROLYSIS AT HTAG SYSTEM SUSPOWER PROJECT
Author Cora Gheorghe
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1. Objective the investigation of the biomass
behaviour during the pyrolysis process at
different temperatures. 2.
Parameters considered the mass losses, the
pellets temperature.

• 3. Description of the test facility
• HTAC experiments were run on a small-scale
  stand. A scheme of the test facility are show in
• the next figure

8 special crew9 small bucket10
nitrogen inlet11 opening glass12
thermocouple which measures the temperature of
the fuel gases13 thermocouple which
measures the temperature of the flue
gases14 gas analysis probe.
1 fuel gas inlet2 mixture of air and
nitrogen inlet3 gas burner4 combustion
chamber5 honeycomb6 second part of the
combustion chamber7 facilitys outlet
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4. Feedstock As a feedstock, we used
wood pellets, with 10 mm diameter and about 15 mm
long.
5. Range of investigations The
investigations were carry out for three
temperature of the feed gas 600, 800 and 1000C
and for different pyrolysis times, range from 15
second to 5 minutes.
6. Results6.1. Mass loss

• The figure 1 help to compare the evolution
  of the mass loss for all three temperatures of
  the experiments. On the plot, we can observe
  three steps of the pyrolysis the first
  horizontal part of the curve represents the
  vaporisation of the water the decreasing
  continuously, when we have the devolatilisation,
  witch is faster the last part of the curve,
  witch become horizontal, the pyrolysis of the
  char occurs. From those three curves, an
  important conclusion results the temperature
  accelerates the kinetic of the mass loss.

Figure 1 Evolution of the mass loss versus time
for the experiments made
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6.2. Temperature of the pellet
a) Feed gas temperature 1000C
b) Feed gas temperature 800C
c) Feed gas temperature 600C
Figure 2 Evolution of the pellet temperature
function of the time for different temperatures
of the feed gas
From the figure 2, concerning the temperature
of the pellet, higher is the temperature of the
feed gas, the temperature of the sample
increases. We can observe that the maximum of the
pellets temperature increases with the
increasing of the experiments time. It cannot
rich the temperature of the feed gas, but it has
a close value. The temperature increases very
rapidly and it remains Stable for a short time.
7. Conclusions
Regarding the HITAG experiments for the
pyrolysis of the wood pellets it can make the
next conclusions. Concerning the mass loss? the
feed gas temperature has a big influence the
temperature accelerates the kinetic of the mass
loss? the vaporisation of the water and the
devolatilisation are speed up by the temperature
of the feed gas? the temperature of the feed
gas does not influence the char from the
pyrolysis.