Environmental Engineering Reference
In-Depth Information
Figure 5. Chemical structure of triglycerides.
3.1.4. Grasses
Grasses are the raw materials for the so-called green biorefinery. This group includes the
large family of green plant materials (green grass from meadows, willow and other natural
resources), alfalfa, clover grass, grass silage, immature cereals and plant shoots (Kromus et
al., 2006). The main components of green plant materials are carbohydrates, proteins, fibers,
fats, amino acids and others. This composition allows to the green biorefinery to produce
biogas, lactic acid, amino acids and fibers. An important green raw material source is the
green harvesting residue material from agricultural cultivated crops, mainly the green foliage
from sugar beet leaves, hemp scrape and leaves.
3.1.5. Lignocellulosic materials
Lignocellulosic materials include dedicated energy crops (such as switchgrass and
miscanthus), agricultural residues, forestry wastes, agroindustrial wastes, and other industrial
wastes. The importance of lignocellulosic biomass as feedstock for biorefinery is evident:
their use allows either the production of valuable biofuels and chemicals able to replace fossil
derived products, and the utilization of a wide range of residues of domestic, agricultural and
industrial activities.
Among the potential large scale industrial biorefineries, the biorefinery systems based on
lignocellulosic feedstocks will most probably achieve the greatest success in terms of market
penetrations and product volumes. On the one side the raw material situation is optimum
(widespread and easily available), on the other side conversion product have a good position
on both the traditional petrochemical and future biobased product market.
All kinds of lignocellulosic biomass are made of three main components: cellulose,
hemicellulose and lignin. Cellulose (see Figure 6) has a strong molecular structure made by
long chains of glucose molecules (C6 sugars) and is one of the most important raw materials
for a variety of industries. Currently, major uses of cellulose are in pulp and paper industry, in
medicine and in pharmacy (Kamm et al., 2006b).
