Biomedical Engineering Reference
In-Depth Information
biological processes is required for optimal operations. The biological reactions are also very
slow and thus require larger facility footprints.
Pyrolysis resembles more closely to the refinery, whereby the products can be controlled in
a more systematical manner. It may be classified as systematical disassembling as well.
However, there are restrictions on the type of products the process can produce. Gasification
as shown in
Fig. 1.3
is at the extreme side of conversion technology, whereby the lignocellu-
losic biomass is disassembled to the basic building block for hydrocarbons: H
2
and CO and
then reassembled to desired products as desired. The final products can be more easily
tailored from syn gas or CO
þ
H
2
. For example, Fischer
e
Tropsch process can turn
CO
H
2
into higher alcohol, alkenes, and many other products. Syn gas (together with
air: mixture of N
2
and O
2
) is also the starting point for ammonia synthesis, from which
nitrogen fertilizers and many other products are produced. However, all thermochemical
processes suffer from selectivity. During the disassembling process, “coke” or “carbon” is
produced especially at high temperatures and thus reduces the conversion efficiency if H
2
and CO are the desired intermediates. Thermal
e
chemical processes are generally considered
þ
O
O
OH
O
HO
HO
OH
OH
OH
O
O
OH
2,3-Butanediol
OH
Lactic acid
Succinic acid
Fumaric acid
O
HO
O
OH
HO
O
OH
OH
HO
3-Hydroxypropionic acid
OH
1,4-Butanediol
Malic acid
O
HO
HO
Butanol
OH
O
O
OH
HO
Ethanol
Itaconic acid
O
OH
HO
O
HO
O
OH
HO
HO
O
OH
Hydrogenation
O
NH
2
5-Hydroxymethylfurfural
OH
Aspartic acid
OH
Oxidation
Hydration
OH
OH
O
O
HO
O
OH
OH
OH
OH
HO
Gluconic acid
OH
Gluconic a
OH
HO
Sorbitol
Sorbitol
OH
OH
NH
2
O
O
OH
Glutamic acid
HO
Levulinic acid
HO
OH
OH
O
FIGURE 1.4
The platform chemicals derived from glucose (the molecule in the center of the diagram). Most of
these chemicals are produced via fermentation (or biotransformation), while a few of them are produced via
chemical reaction (or chemical transformation) as indicated.
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