Biomass Fuel Quality Enhancement and Respiratory Quotient (RQ) for Ranking Fossil and Biomass Fuels Based on CO2 Emissions - Novel Combustion Concepts for Sustainable Energy Development - page 58

Fig. 6 Torrefaction of
mesquite at 240 ° C for
60 min: results predicted by
TCM

1

500

0.8

450

0.6

0.4

400

Temp
Hemicellulose f
Cellulose f
Lignin f
Total F

0.2

350

0

0 10 20 30 40 50 60

time (minutes)

The loss of volatiles from the three components of mesquite after 60-min time
period at 240

C was predicted to be 71.5, 1.39, and 1.46 % for hemicellulose,
cellulose, and lignin, respectively, on a dry ash-free basis. The overall dry ash-free
mass loss from the biomass sample was 18.1 %. The results obtained from previous
torrefaction experiments carried out on smaller samples (10 mg) in a TGA on a dry
ash-free basis were used as a reference for comparison with model results. It should
also be noted that the juniper which is a softwood shows lower mass loss due to
lower percentages of hemicellulose in the sample.
Effect of temperature on the torrefaction process was studied using TCM.
Figure 7 compares the TCM results with the experimental results for a residence

°

Fig. 7 Effect of temperature
on the loss of volatile matter
from the samples. Results
from the model are compared
with experimental results.
M Mesquite; J Juniper; TCM
Three-component model;
t res = 60 min

90

80

70

60

50

M-TCM
J-TCM
M-experiment
J-experiment

40

30

200 220 240 260 280 300

Temperature ( o C)