Biofuel like biodiesel, plant oil, ethanol, bio methane or the synthetic biomass- to- liquid (BtL)- fuels everyone is talking about them. They are at present the only renewable alternative in the mobility sector and already today make up 6.1 % of the fuel consumption in Germany.
However, in the past months and years biofuels had the reputation to generate a social- und environmental dilemma. For example, in developing countries large areas were cleared and used for sugar cane biofuel monocultures or similar and therefore were at the same time unintentionally in competition with the production of food.
Inevitably, lead this well-known problem to the development of more climate friendly and socially acceptable uses of second generation bio fuels. So for first generations bio fuels solely sugar respectively the oily contents of the infructescence of a plant were used. In contrast, with second generation bio fuels only the cellulose, respectively hemicellulose containing parts of the plant; mostly the stem axes or leaves of the plant were used. This type of utilization has three decisive advantages: For one the fuel is not in competition with food or animal feed production, since the infructescence like for example a kernel of corn, can still be used for the production of food, second the part of plants containing cellulose are considered the energy richer parts. As a third aspect the production costs have to be considered. The plant parts containing only cellulose respectively hemicellulose are clearly much more reasonable available from the raw materials market than those with a high degree of nutrients like for example mono or disaccharides, proteins or lipids.
Bio ethanol is produced and obtained via biocatalysis (fermentation) and bio process technology. In order to run such well-engineered bio process technology plants, as a rule, a preparation of the lignocellulose containing residual material is required. Not only the degree of the comminution (particle size) due to the installed technical components of the plant, like valves and the built-in measurement instrumentation and control systems play a part, but rather what seems even more important is the produced by the comminution high surface and the associated residence time and fermentation period in the bio-fermenter. Hereby the used micro organisms and enzymes are given the opportunity in a time- and resource saving approach to achieve the highest possible plant effectiveness.