Environmental Engineering Reference
In-Depth Information
9.1%
100
H
2
O
80
60
40
8
20
Hemicellulose
6
Cellulose
Lignin
-dTG
4
2
0
0
100
200
300 400
Temperature, °C
500
600
700
Figure 3.12
Comparison of thermal behavior of biomass components within the torrefaction
temperature range.
typical of high-temperature conventional pyrolysis ranging from gases, liquids, and
solids. Furthermore, this low-temperature microwave process is scalable, energy
efficient, and generates five major types of products from lignocellulosic biomass:
1. a high-quality char with properties superior to those achieved by most conven-
tional methods and with an enhanced energy value, feedability, and grindabil-
ity, making it suitable as a coal replacement;
2. bio-oil, suitable for upgrading to liquid fuel;
3. an aqueous solution of organic acids and aldehydes;
4. an aqueous solution of sugars; and
5. a gas fraction containing combustible organic compounds, which could be
used for energy production.
Commercial development of torrefaction is currently in its early phase. Several
technology companies and their industrial partners are moving towards commer-
cial market introduction. The current demand for torrefied biomass of utilities
alone greatly exceeds the production capacity that can be realized in the coming
years. An overview of reactor technologies that are applied for torrefaction is
provided in Table 3.4.
Most torrefaction technology developers listed in Table 3.4 are companies with
extensive backgrounds in biomass processing and conversion technologies such
as carbonization and drying. The reactors being developed are, in most cases,
