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chemical energy balance was determined including the distribution of the major
elements (C, H, O). In total, 19 different experiments were performed. The
interpretation and evaluation of all the experimental results are reserved for an
upcoming publication by the authors and this work focuses on the mass and chemical
energy balance from one of these experiments. The conditions for the chosen
experiment were as follows: heating rate of 13 °C/min, 500 °C final temperature, and a
soak time of 3 hours.
Results and discussion
The composition and heating values for all the products including the original feedstock
used in the pyrolysis experiment are displayed in Table 1. Notice that the standard
proximate analysis was not performed for the condensate, since it was not regarded as
applicative. The biomass analysis reveals no surprises and falls within similar values
which can be found in tables and databases (for example [11]) for biomass. For the
charcoal; since the entire proximate analysis is normalized and the moisture content is
low; the corresponding fixed carbon content is quite high. However, if the moisture
content is adjusted to 15%, which is the upper limit for an Elkem charcoal the fixed
carbon content is reduced to roughly 72%, which is still well within the given process
requirements (>60%). It is also worth mentioning that the 2% moisture content in the
charcoal from the experimental campaign is more than likely absorbed humidity (from
surrounding air) from when the sample was handled. The obtained condensate contains
33% moisture which is slightly higher than typical values reported for fast pyrolysis
oils which are around 25% using different types of fast pyrolysis technologies [12].
Table 1.
Proximate and ultimate analysis and heating value of the original feedstock used in
the pyrolysis experiments together with the analysis of the obtained charcoal, condensate and
gas.
Pine wood chips Charcoal Condensate Gas
Moisture
25.4
2.0
33 -
Ash
0.2
0.8
0.002 -
Volatiles
61.2 14.5
-
-
Fixed carbon
13.2 82.8
-
-
C
53.4 86.9
35.5 36.7
H
6.4
2.8
8.5 2.0
O
39.9 10.2
55.9 61.3
N
0.2
0.1
nd.
-
S (mg/kg)
67.7 172.0
nd. na.
Cl (mg/kg)
37.9 43.0
nd. na.
HHV
17.4 32.6
15.3 7.9
Proximate analysis (as received wt-%)
Ultimate analysis (wt-%, solids as dry)
Higher heating value (MJ/kg )
4