Page 28 - Academic Press Encyclopedia of Physical Science and Technology 3rd BioTechnology

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Encyclopedia of Physical Science and Technology EN002G-61 May 19, 2001 19:33

Biomass, Bioengineering of 153

toxicity, but by high oxygen demands if processed in con- industry. The more biorefineries that are established and
ventional sewage treatment facilities. Solid wastes from become successful, the more that will be built as risks
biomass processing could occupy large volumes of landfill decline and “know how” increases.
space, and would tend also produce high oxygen demand The cumulative effect of incremental process improve-
liquid effluents from landfills. ment is to cause the raw material costs to eventually be-
The volume of landfill space that might be occupied come the dominant cost factor. This has already occurred
by these products is remarkable, particularly for biobased with the oil refining industry and will take place in the
fuels. For example, corn stover contains approximately biomass processing industries as these are established
10–12% of protein and fat, in addition to the 70–75% of and grow to maturity. In this regard, biorefineries have a
the plant material that is carbohydrate and that could be significant potential advantage over petroleum refineries
converted to fuel ethanol in a large fermentation facility. because plant-based raw materials are abundant, widely
If no economic uses are found for the protein and fat or available and inexpensive. The availability and prices of
if economical recovery processes are not developed, these plant raw materials may thus be more stable and pre-
biomass components will have to be burned, landfilled, dictable than those of petroleum. As we have seen, plant
or treated as sewage and the resulting sludge disposed raw material prices are already comparable on a cost per
of. A hypothetical ethanol plant producing 100 million ton basis with petroleum and coal. Over time, petroleum
gallons of ethanol per year (less than 0.1% of current U.S. prices must rise to reflect the fact that it is a nonrenewable
gasoline demand) from 1 million tons of corn stover will resource, while there is the potential to keep biomass costs
also produce at least 100,000 tons of protein and fats. low indefinitely.
Assuming a bulk density of about 50 lb per cubic foot,
this much protein and fat will occupy a volume equivalent 4. Innovation and Risk
tothesurfaceareaofafootballfieldstackedapproximately
100 ft deep. Clearly there is strong economic incentive to While biorefineries have some inherent advantages over
find uses for all of the components of biomass. petroleum refineries, they also have some significant dis-
Therefore, as has occurred with the oil refining industry, advantages. First, the costs and risks of petroleum refining
“biorefineries” will tend to emerge. These biorefineries are well understood and the commodity organic chemicals
will be large, highly integrated processing plants that will industry based on petroleum is very well developed. How-
yieldnumerousproductsandwillattempttosellapoundof ever, the costs and risks of biomass refining are not nearly
product for every pound of raw material entering the plant. so well understood, particularly for large scale plants con-
Prototype biorefineries already exist, including corn-wet verting lignocellulosic biomass into fuel ethanol. Innova-
and dry mills, soybean processing facilities and pulp and tion is always regarded as risky compared to the status
paper mills. quo. Investors demand a greater return on investment to
The number and variety of these biobased products will compensate for these increased risks and they also require
increase over time, as has occurred with the oil refining additional capital investment in the processing plant to re-
industry. Many biorefinery products can also be produced duce processing risks or uncertainties. Second, when the
by oil refineries; including liquid fuels, organic chemi- petroleum industry was new there was little or no compe-
cals and materials. However, biorefineries can make many tition for many of its products as they emerged. However,
other products that oil refineries cannot, including foods, most of the potential new biobased products must com-
feeds,andbiochemicals.Theseadditionalcapabilitiesgive pete with a comparable petroleum-derived product. These
biorefineries a potential competitive edge and may provide two factors are significant hurdles for biomass processing
increased financial stability. industries to overcome.
A better fundamental understanding of the underlying
science and technology for biomass conversion processes
3. Incremental Process Improvement
could reduce the risks of such processes as they are
As we have seen, the number of products from a refinery scaled up to commercial practice. Better fundamental un-
tends to increase with time. In addition, the processing derstanding would reassure investors and allow them to
technologies used by refineries tend to improve incremen- reduce the return on investment required. Better funda-
tally over time. This is partly due to research that improves mental understanding of the processes would also tend to
or replaces existing processes, supported within the cost reduce the processing equipment redundancy required be-
structure of a successful industry. Research targets those cause of lack of certainty about its proper functioning un-
process elements that most impact the overall cost of con- der commercial practice. Some of the key areas of biomass
version. Incremental cost reduction is also partly due to or- processing in which greater fundamental understanding is
ganizational learning that can only occur in a functioning required are discussed below.