Environmental Engineering Reference
In-Depth Information
<$0.50 per gallon bioethanol in 2004 and targets were set to reduce the costs to
further for a viable technology. On the Cellulosic Roundtable [36] in November
2008 the Novozymes Global Director (Biofuels) Poul Ruben Andersen said: “The
aim of Novozymes is to develop the first commercially relevant enzyme sys-
tem needed for efficient and economical conversion of cellulosic materials into
ethanol. This is the largest effort we have undertaken in our history and we plan
to have this ready by 2010 for the first large scale plants expected to come on line
in 2011.”
Biogas technology utilises an organic and agricultural waste approach and
continues to develop steadily with a growth in the number of installations that
are appearing. While some use the biogas for local use (electricity generation),
companies have been created that allows the upgrading of biogas to methane
that is able to substitute natural gas (SNG) and be introduced into national gas
supply pipelines. Some research has also been taking place in order to improve
the digestibility of other lignocellulosic material with high lignin content, for
instance bracken [37, 38]. Again the use of pretreatment technology is used as a
means to improve the hydrolysis process.
3.2 Use of the Correct Raw Materials and Technology
at the Right Scale
An article by Banholzer in 2008 [39], examined the use of various feedstocks to
prepare olefins. Where carbohydrate containing feedstocks were used this involves
ethanol production and integrated conversion to ethylene. Here capital and variable
costs (feedstock costs) were plotted, with the diagonal lines showing the approx-
imate equivalency of economic-cost-of-production. An adapted version, which
includes an estimation for FT technology, is seen in Fig. 3. Interestingly the possible
use of lignocellulosic biomass or starch or naphtha sit on the same economic-cost-
of-production but illustrates the balance between the advantage of low biomass costs
at the expense of (potential) high capital costs in order to build the facility.
4 Conclusion
In conclusion, biofuels can be readily produced from a number of biomass materials
using a number of technologies. With the advent of second generation technol-
ogy the production of bioethanol using lignocellulosic biomass (as an alternative
to the use of sugar and starch) is being realised. Technologically, there are a num-
ber of solely chemical based methods (for pretreatment and hydrolysis) and some
that make use of cellulase enzymes for the hydrolysis process. As well as this
there are a number of options available to metabolise pentoses in the fermenta-
tion process to bioethanol (compared to traditional hexose metabolism of bakers
yeast) therefore improving the over production potential of the biomass. It has taken
many years of biotechnological development to achieve this but the technology
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