Page 81 - Biofuels Refining and Performance

64 Chapter Two

Direct combustion of biomass for heat generation is the most inefficient
technique in energy economy, heat being the most inefficient of all forms
of energy. The best way to utilize biomass is to recycle biomass for pro-
duction of other or further biomass, namely, agriculture, horticulture,
aquaculture, poultry, animal farming, and so forth. Randomness is
reduced (low entropy change), and environmental chaos is lessened.
Properties (a), (c), and (d) are significant for farming; (b) and (f) are
important for hydrolytic processes; and (e) is important for biofuels and
biodiesel. All the points are important for fermentations and in biore-
fineries. Biorefinery has become a new science and technology harmony
for a promising future, which takes care of different aspects of biosafety,
minimizes waste, and maximizes energy efficiency. It is a field of engi-
neering and technology for the future. Biorefinery is a system similar to
that of petroleum in its requirements for producing fuels and chemicals
from biomass. A biorefinery is a capital-intensive project and is based on
a conversion technology process of biomass. Hence, several technologies—
thermochemical, chemical, biochemical, and so forth—are combined to
reduce the overall cost. Fernando et al. suggest an integrated biorefinery
process from bio-oil produced from pyrolysis of biomas (see Fig. 2.12),

Lignin
intermediates
Feedstock Lignin
handling products
Pretreatment
Hydro-
Crude oil cracking Gasification/
refinery pyrolysis Sugar
Enzymatic intermediates
Hydrogen hydrolysis of
products Gas cellulose Sugar
conditioning intermediates
& separation
Multisugar
Fuel fermentation
products
Synthesis
Fermentation
Ethanol
recovery for
Steam and bioproducts
power
generation Lignin
residue
Electricity Fuel ethanol Bioproducts
coproduct
Figure 2.12 An integrated biorefinery process. (Permission from S. Fernando, Associate
Editor, FPEI—American Society of Agricultural and Biological Engineers (ASABE),
Mississippi State University, USA.)