Page 70 - Biomass Gasification, Pyrolysis And Torrefaction Practical Design and Theory

Chapter | 3 Biomass Characteristics 49

into glucose (represented by CH m O n ), releasing O 2 as a waste product. The pro-
cess may be represented by this equation (Hodge, 2010, p. 297):
chlorophyll
Living plant 1 CO 2 1 H 2 O 1 sunlight !ðCH m O n Þ 1 O 2 2 480 kJ=mol
(3.1)
For every mole of CO 2 absorbed into carbohydrate or glucose in biomass,
1 mol of oxygen is released. This oxygen comes from water the plant takes from
the ground or the atmosphere (Klass, 1998, p. 30). The chlorophyll promotes the
absorption of carbon dioxide from the atmosphere, adding to the growth of the
plant. Important ingredients for the growth of biomass are therefore:
Living plant
Visible spectrum of solar radiation
Carbon dioxide
Chlorophyll (serving as catalyst)
Water.
The chemical energy stored in plants is then passed on to the animals and
to the humans that take the plants as food. Animal and human wastes also
constitute biomass.

3.2.2 Types of Biomass
Biomass comes from a variety of sources as given in Table 3.1. European
committee for standardization published two standards for classification and

TABLE 3.1 Two Major Groups of Biomass and Their Subclassification
A. Virgin biomass A.1 Terrestrial biomass i. Forest biomass
ii. Grasses
iii. Energy crops
iv. Cultivated crops
A.2 Aquatic biomass i. Algae
ii. Water plant
B. Waste biomass B.1 Municipal waste i. MSW
ii. Biosolids, sewage
iii. Landfill gas
B.2 Agricultural solid waste i. Livestock and manures
ii. Agricultural crop residue
B.3 Forestry residues i. Bark, leaves, floor residues
B.4 Industrial wastes i. Demolition wood, sawdust
ii. Waste oil/fat