Environmental Engineering Reference
In-Depth Information
Sugar platform
(biochemical)
Food & feed
Chemicals
Materials
Energy
Biomass
Syngas platform
(thermochemical)
Figure 1.13
Simplified diagram of a two-platform biorefinery.
1.5.2.3.4 Two-Platform Biorefinery
Another form of biorefinery recently defined by the National Renewable Energy
Laboratory (NREL) is the two-platform biorefinery. As depicted in Figure 1.13,
the feedstock is separated into a sugar platform (biochemical) and a syngas plat-
form (thermochemical). Both platforms can offer energy, chemicals, materials
and potentially food and feed, therefore making use of the entire feedstock(s) (see
Chapter 3). The sugar platform is based on biochemical conversion processes and
focuses on the fermentation of sugars extracted from biomass feedstocks. The
syngas platform thermolytically transforms biomass into gaseous or liquid inter-
mediate chemicals that can be upgraded to transportation fuels as well as com-
modity and speciality chemicals [45].
No biorefinery of this type currently exists in Europe but sugar conversion
technologies (e.g. wheat grain-to-ethanol fermentation) and gasification
approach (e.g. Linde's Carbo-V® process) are independently used. Opinions
vary widely on the best strategy to combine these two platforms. However, it is
most likely that, as new technologies are developed, multiple biorefinery designs
will emerge commercially depending on the location of the plant and the
feedstock(s) used.
Importantly, the sugar platform and many other (non-thermochemical) pro-
cesses likely to be incorporated into a biorefinery will almost certainly generate
some waste products that will be difficult to convert into value-added materials
and chemicals. Such wastes and residues could potentially represent an important
source of energy within the biorefinery, and are an ideal candidate for thermo-
chemical conversion [46].
1.5.2.3.5 Marine Biorefinery
There is considerable interest in the use of micro- and macro-algae (seaweed) as
a biorefinery feedstock to produce food, feed, biofuels and chemicals. Although
their potential is considerable, marine biorefineries are in their infancy compared
to the other types of phase III biorefineries (based on terrestrial crops) described
in the preceding sections [47].
