Article

Synthetic biofuels

In the production process of the various synthetic biofuels a conversion of the chemical structure of the raw materials takes place. The quality of the final product is largely dependent on the synthesis processes, but not on the feedstock which determines only the steps to be set and the yield. A basic distinction is made between liquid (“Biomass to Liquid”, BtL) and gaseous synthetic fuels.

In biomass-based facilities the generation of district heating and electricity is possible in addition to fuel synthesis. This co-production not only increases the efficiency but also the potential of CO2 savings.

 

Fischer-Tropsch Fuels

The Fischer-Tropsch synthesis is an exothermic process in which different hydrocarbons can be constructed. Carbon monoxide and hydrogen will initially create CH2 building blocks that join together ultimately to long-chain hydrocarbons. In this process metal catalysts are used. Because of side reactions during chain growth a true variety of structures of the end products is build, such as branched and linear alkanes and olefins of different length or oxygen compounds. The diversity of the molecular structures on the one hand leads to a disadvantageous, lower selectivity of the reaction, however, on the other hand allows a precise control of the fuel properties. Via Fischer-Tropsch synthesis, all mineral fuels can be produced from biomass. The recovered fuels are characterized by their high quality and any miscibility to fossil fuels.

Synthetic natural gas

Main component of fossil natural gas is methane, which can be also produced synthetically in a strong exothermic conversion. The reactants carbon monoxide and hydrogen are in a ratio of 1:3 and form methane and water. In Güssing (Burgenland) the world's Bio-SNG (Synthetic Natural Gas) plant became operational in mid-2009. There wood gas from the adjacent biomass power plant was processed. In this biomass power plant wood chips are gasified, which can be converted either by direct firing to heat and electricity or to synthetic natural gas.

Gasification of wood to synthesis gas

Gasification of wood to synthesis gas
(c) BIOENERGY 2020+

Further information