Environmental Engineering Reference
In-Depth Information
Biomass started to become popular again even in the industrialized countries when
oil prices began rising dramatically at the beginning of the twenty-fi rst century. In
addition to its traditional use in the form of fi rewood, modern forms of biomass are
now being exploited. Biomass is not only used to kindle simple open fi res but also
to operate modern heating systems and power plants for generating electricity as
well as to produce combustible gases and fuels.
12.1 Origins and Use of Biomass
The term 'biomass' refers to a mass of organic material. It comprises all forms of
life, dead organisms and organic metabolism products. Plants are able to create
biomass in the form of carbohydrates through photosynthesis. The energy needed
is supplied by the sun (Figure 12.2). Only plants carry out this process; animals can
produce biomass only from other biomass. This is why all animals would starve to
death without plants.
Figure 12.2
The sun is responsible for the growth of biomass on earth.
Origin of Biomass
Through photosynthesis plants convert carbon dioxide (CO
2
), water (H
2
O) and
auxiliary substances like minerals into biomass (C
k
H
m
O
n
) and oxygen (O
2
):
HO CO
++
auxiliary materials
+
energy
→
CH O
++
HO O
2
+
2
2
k
m
n
2
biomass
metabolic products
In the simplest case, so-called oxygenic photosynthesis produces glucose (C
6
H
12
O
6
):
12
H O
+
6
CO
+
solar energy
→
C H
O
+
6
H O
+
6
O .
2
2
6 26
2
2
