Download Folie 1

Back
Back
Fermentation is the process of deriving energy from the oxidation of
organic compounds, such as carbohydrates, using an endogenous electron
acceptor, which is usually an organic compound.
Fermentation gas is a mixture from the
main components
•methane
•carbon dioxide.
Besides it contains small quantities of
water vapour, hydrogen sulfide, ammonia,
hydrogen, N2.
The process involves a biological/chemical method for converting any
biodegradable material (urban wastes  municipal solid waste, biodegradable
waste and sewage sludge) into useful chemicals: carboxylic acids, ketones and
biofuels, such as a mixture of primary alcohols (e.g., ethanol, propanol, butanol) and/or
a mixture of secondary alcohols (e.g., isopropanol, 2-butanol, 3-pentanol).
Because of the many products that can be economically produced, this process is a
true biorefinery.
As the microoganisms anaerobically digest the biomass and convert it into a
mixture of carboxylic acids, the pH must be controlled.
This is done by the addition of a buffering agent
ammonium bicarbonate
calcium carbonate
Acetic acid, unlike ethanol, is biologically produced from simple sugars
without the production of carbon dioxide:
C6H12O6  2 CH3CH2-OH + 2 CO2
(Biological production of ethanol)
C6H12O6  3 CH3-COOH
(Biological production of acetic acid)
3 CH3-COOH + 6 H2  3 CH3CH2-OH + 3 H2O
(Hydrogenation of acetic acid)
Biologically produced alcohols, most commonly ethanol and less commonly
propanol and butanol, are produced by the action of microorganisms and
enzymes through fermentation.
Butanol will produce more energy and
allegedly can be burned "straight" in
existing
gasoline
engines
(without
modification to the engine or car), and is
less corrosive and less water soluble than
ethanol, and could be distributed via
existing infrastructures. DuPont and BP
are working together to help develop
Butanol.
• can be used for either food or fuel, but the quality of the oil may be lower for
fuel use
• can be used in many older diesel engines (equipped with indirect injection
systems), but only in warm climates
• is used to manufacture biodiesel, which is compatible with most diesel
engines when blended with conventional diesel fuel
MAN B&W Diesel, Wartsila and Deutz
AG offer engines that are compatible
with straight vegetable oil. Used
vegetable oil is increasingly being
processed into biodiesel, and at a
smaller scale, cleaned of water and
particulates and used as a fuel.
Recognizing the importance of implementing bioenergy, there are international organizations
such as IEA Bioenergy, established in 1978 by the OECD International Energy Agency (IEA), with
the aim of improving cooperation and information exchange between countries that have national
programs in bioenergy research, development and deployment. The U.N. International Biofuels
Forum is formed by Brazil, China, India, South Africa, the United States and the European
Commission. The world leaders in biofuel development and use are Brazil, United States, France,
Sweden and Germany.
• Brazil  the government hopes to build on the success of the Proálcool ethanol program by
expanding the production of biodiesel which must contain 2% biodiesel by 2008, increasing to
5% by 2013.
• USA  A senior member of the House Energy and Commerce Committee Congressman Fred
Upton has introduced legislation to use at least E10 fuel by 2012 in all cars in the USA.
• Europe  The European Union in its biofuels directive (updated 2006) has set the goal that
for 2010 that each member state should achieve at least 5.75% biofuel usage of all used traffic
fuel. By 2020 the figure should be 10%. As of January 2008 these aims are being reconsidered
in light of certain environmental and social concerns associated with biofuels such as rising
food prices and deforestation.
• China  The government is making E10 blends mandatory in five provinces that account for
16% of the nation's passenger cars.
• South Asia  Thailand has mandated an ambitious 10% ethanol mix in gasoline starting in
2007. For similar reasons, the palm oil industry plans to supply an increasing portion of national
diesel fuel requirements in Malaysia and Indonesia.
Students:
•Mihut Radu
•Stoica Andrei-George
Coordonated by:
Professor Schnabel Dieter