Transcript 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