Environmental Engineering Reference
In-Depth Information
Feedstock
production and
logistics
Distribution
and end uses
Biomass conversion
Existing corn
wet mills
Biofuels:
Bulk distribution
infrastructure
Retail marketing
network
Vehicles
Corn & Grain
Existing corn
dry mills
Natural oils
processing
Oilseeds and Plants
Agricultural
residue processing
Agricultural Residues
Biopower:
Grid connectivity
Co-firing
Energy crops
processing
Energy Crops
Bioproducts:
Bulk distribution
infrastructure
Chemical
intermediate
market
Consumer market
Forest resources
processing
Forest Resources
Industrial and
Other Wastes
Waste processing
FIGURE 5.3
Resource-based biorefinery pathways.
c
omposition
oF
B
iomass
The ease with which biomass can be converted to useful products or intermediates is
determined by the composition of the biomass feedstock. Biomass contains a variety
of components, some of which are readily accessible and others that are much more
difficult and costly to extract. The composition and subsequent conversion issues for
current and potential biomass feedstock compounds are listed and described below:
•
Starch
(glucose) is readily recovered and converted from grain (corn, wheat,
rice) into products. Starch from corn grain provides the primary feedstock
for today's existing and emerging sugar-based bioproducts, such as polylac-
tide, as well as the entire fuel ethanol industry. Corn grain serves as the pri-
mary feedstock for starch used to manufacture today's biobased products.
Corn wet mills use a multistep process to separate starch from the germ,
gluten (protein), and fiber components of corn grain. The starch streams
generated by wet milling are very pure, and acid or enzymatic hydrolysis is
used to break the glycosidic linkages of starch to yield glucose. Glucose is
then converted into a multitude of useful products.
