Petrochemical hydrocarbon sources are finite and many experts suggest that
they will become exhausted within decades. In addition, both natural gas and
crude oil have recently experienced an upward shift in pricing trends. The
use of bio-based sources such as plant/crop wastes provides inputs that are
renewable and creates the opportunity for a transition to a more sustainable
economy. There is also the hope that in the near future, cellulosic plant/crop
wastes will become economically competitive with petrochemical feedstocks.
There are numerous challenges, both technical and infrastructure related,
associated with commercializing lignocellulosics as feedstocks for chemicals.
While large quantities of various crop wastes go unused throughout the world,
these lignocellulosic materials are difficult to efficiently convert into
chemical products due to their complex polymeric structures. A multi-disciplinary
approach that couples biotechnology and chemistry with process engineering
is necessary in order to achieve efficient commercial processes. In addition
to the technical challenges of commercializing this technology, there are
also large infrastructure barriers. These barriers are associated with the
development of new agricultural infrastructure for the collection and storage
of crop wastes. An integrated feedstock supply system must be developed that
can supply the feedstock needs in a sustainable fashion at a reasonable cost.
Infrastructure issues could be as important as the technical issues when considering
overall production costs.
In this report, PEP presents process designs and associated cost estimates
for the production of two chemicals, ethanol and lactic acid, from agricultural
wastes. Technology development is in the semi-commercial stage in North America,
Europe and Japan for economically producing fuel grade ethanol from a crop
waste such as corn stover, wheat straw or rice straw. Process economics are
also estimated for producing lactic acid from corn stover, a technology that
is more recently under development. Ultimately, the best process economics
for the use of these feedstocks could come through the development of the
"biorefinery," a concept also discussed in this report. For lignocellulosic
biomass to be economically viable as an ethanol feedstock, the Department
of Energy has chosen a target ethanol selling price of $1.07 per gallon (28¢
per liter) as a goal for 2010. Our PEP analysis indicates that more progress
must be made in biomass conversion technology to meet that goal. Our PEP analysis
of lactic acid production from corn stover indicates a good potential for
manufacturing the chemical profitably at prices significantly below current
market prices. Corn stover has a good potential as a lactic acid feedstock
after conversion technology has been demonstrated at the commercial scale
for producing ethanol. For those in the chemical industry, this report will
be useful for the comparative economics it provides, as well as for its extensive
review of ongoing research related to biomass conversion technologies. The
report reviews and analyzes more than 200 recent patents and articles related
to biomass conversion. The report's review of biomass availability around
the world will also be useful for those exploring this field.
By: Greg Bohlman
