Environmental Engineering Reference
In-Depth Information
Research shows that bio-oil formation is favored by short residence times (in the order of
few seconds) and temperatures around 500°C, which is called “fast pyrolysis” (Bridgwater
et al., 1999). Quick quenching immediately after the fast pyrolysis stops the reaction and avoid
further degradation of the compounds contained in the bio-oil (Mohan et al., 2006).
Bio-oil can be burned in boilers, used as fuel in diesel engines and turbines (with limita-
tions), upgraded into transportation fuels, fermented to produce ethanol, converted into
syngas, and used as feedstock for the production of fuels. The use in diesel engines requires
modifications and special start up and shut down procedures; therefore, efforts have been
made in creating a blend with regular diesel by emulsification, which would allow the use of
regular unmodified diesel engines (Chiaramonti et al., 2003). In contrast with regular biomass,
bio-oil as a fuel has the advantages of being easy to transport, store, and retrofit to existing
equipment (Bridgwater et al., 1999).
The gas fraction generated during bio-oil production, pyro-gas and as syngas have an
assortment of applications, including fuel, transformation into alkenes via the Fischer-Tropsch
process, transformation into ethanol and methanol via catalytic reactions, or used for produc-
tion of ammonia after steam reforming (Ebert, 2008).
CHEMICALS FROM SUGARS
The Department of Energy (DOE) established a list of “twelve building block chemicals,” that
will be building blocks for the production of other chemicals and materials. The twelve com-
pounds, listed in Table 14.2, in most cases produced by fermentation of sugars, have func-
tional groups with the capability of being transformed into other compounds via chemical
routes (Werpy and Petersen, 2004).
The descriptions presented in the following paragraphs of this section have been summa-
rized from Werpy and Petersen (2004).
Succinic, fumaric, and malic acids comprise a family of 4-carbon dicarboxylic acids with
similar chemical properties. These compounds produced from glucose with genetically
Table 14.2
The twelve chemicals producible from sugars that will be the building blocks to synthesize
chemicals.*
Building block
Main production routes
1,4-Succinic, fumaric and malic acids
Aerobic fermentation with yeast/fungi or bacteria
2,5-Furan dicarboxylic acid
Chemical
3-Hydroxypropionic acid
Synthesis, extraction from protein, aerobic fermentation with
yeast/fungi of bacteria
L-aspartic acid
Aerobic fermentation with yeast/fungi of bacteria and
biotransformation
Glucaric acid
Chemical
Glutamic acid
Aerobic fermentation with yeast/fungi
Itaconic acid
Aerobic fermentation with fungi
Levulinic acid
Chemical
3-Hydroxybutyrolactone
Chemical
Glycerol
Aerobic/anaerobic fermentation with yeast/fungi or bacteria
and chemical
Sorbitol
Chemical
Xylitol/arabinitol
Chemical
*List selected by Department of Energy (National Renewable Energy Laboratory, 2004).
