6
Chapter
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1 Introduction
From these come four major categories of product:
Chemicals such as methanol, fertilizer, and synthetic fiber
Energy such as heat
Electricity
Transportation fuel such as gasoline and diesel
The use of ethanol and biodiesel as transport fuels reduces the emission of
CO
2
per unit of energy production. It also lessens dependence on fossil fuel.
Thus, biomass-based energy not only is renewable but is also clean from a
greenhouse gas (GHG) emission standpoint, and so it can take the center stage
on the global energy scene. This move is not new. Civilization began its energy
use by burning biomass. Fossil fuels came much later, around 1600 A
.D. Before
the twentieth
century, wood (a biomass) was the primary source of the world’s
energy supply. Its large-scale use during the early Industrial Revolution caused
so much deforestation in England that it affected industrial growth. As a result,
from 1620 to 1720 iron production decreased from 180,000 to 80,000 tons per
year (Higman and van der Burgt, 2008, p. 2). This situation was rectified by
the discovery of coal, which began displacing wood for energy as well as for
metallurgy.
Chemicals
Most chemicals produced from petroleum or natural gas can be produced from
biomass. The two principal platforms for chemical production are sugar based
and syngas based. The former involves sugars like glucose, fructose, xylose,
arabinose, lactose, sucrose, and starch.
The syngas platform synthesizes the hydrogen and carbon monoxide con-
stituent of syngas into chemical building blocks. Intermediate building blocks
for different chemicals are numerous in this route. They include hydrogen,
methanol, glycerol (C3), fumaric acid (C4), xylitol (C5), glucaric acid (C6),
and gallic acid (Ar), to name a few (Werpy and Petersen, 2004). These inter-
mediates are synthesized to produce large numbers of chemicals for industries
involving transportation, textiles, food, the environment, communications,
health, housing, and recreation. Werpy and Petersen (2004) identified 12 inter-
mediate chemical building blocks having the highest potential for commercial
products.
Energy
Biomass was probably the first on-demand source of energy that humans
exploited. However, less than 22% of our primary energy demand is currently
met by biomass or biomass-derived fuels. The position of biomass as a primary
source of energy varies widely depending on the geographical and socio
-
economic conditions. For example, it constitutes 90% of the primary energy
source in Nepal but only 0.1% in the Middle East. Cooking, although highly