Environmental Engineering Reference
In-Depth Information
Developments in pyrolysis, ultracentrifuges, and membranes, as well as the use of
enzymes and microbes as biological factories, are enabling the extraction of valu-
able components from plants at a much lower cost. As a result, industry is investing
in the development of new bioproducts that are steadily gaining a share of current
markets (USDOE, 2004).
New technologies are helping the chemical and food processing industries to
develop new processes that will enable more cost-effective production of all kinds
of industrial products from biomass. One example is a plastic polymer derived from
corn that is now being produced at a 300-million-pound-per-year plant in Nebraska,
a joint venture between Cargill, the largest grain merchants, and Dow Chemical, the
largest chemical producer (Fahey, 2001).
Other chemical companies are exploring the use of low-cost biomass processes
to make chemicals and plastics that are now made from more expensive petro-
chemical processes (USDOE, 2006a). In this regard, new innovative processes
such as biorefineries may become the foundation of the new bioindustry. A bio-
refinery is similar in concept to a petroleum refinery, except that it is based on
conversion of biomass feedstocks rather than crude oil. Biorefineries in theory
would use multiple forms of biomass to produce a flexible mix of products, includ-
ing fuels, power, heat, chemicals, and materials (see Figure 5.1). In a biorefinery,
biomass would be converted into high-value chemical products and fuels (both
gas and liquid). Byproducts and residues, as well as some portion of the fuels
produced, would be used to fuel onsite power generation or cogeneration facilities
producing heat and power. The biorefinery concept has already proven success-
ful in the U.S. agricultural and forest products industries, where such facilities
now produce food, feed fiber, or chemicals, as well as heat and electricity to run
plant operations. Biorefineries offer the most potential for realizing the ultimate
opportunities of the bioenergy industry. Table 5.1 s hows the energy consumption
by energy source for 2008; in that year, biomass (biofuels, waste, wood, and wood-
derived fuels) accounted for 3852 quadrillion Btu.
C 5 , C 6 sugars
Fiber
hydrolysis
Catalysis
Fuels
and
chemical
products
and inter-
mediates
for other
platforms
Corn
grain
Starch/cellulose
hydrolysis
Fermentation
Glucose
Syngas
conversion
Agricultural residues,
other energy crops
Gasification
Electricity
Steam
Combined heat
and power
FIGURE 5.1
A biorefinery.
 
 
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