With over 100,000 GWh or 370 PJ (Basic data Bioenergy Germany 2017, Fachverband Nachwachsende Rohstoffe e.V.) in Germany hay, straw, wood and plant residues represent an energy and material potential that has so far been insufficiently exploited. However, in the case of direct combustion or torrefaction according to the state of the art, valuable organic ingredients such as acids (acetic acid, levulinic acid, formic acid), furfurals or aromatic compounds (phenol, vanillin) are not fully utilized in the sense of a biorefinery; the economic efficiency of energy utilization thus remains limited.
Project goal and approach
With VALORKON, a completely new – fermentation-free – biorefinery concept for biomass from agricultural and forestry residues is being developed. A process for drying and torrefaction with superheated steam (SHS) is used, which Fraunhofer IGB has developed together with its project partner Heckmann in previous projects. With rising temperatures in the torrefaction process valuable volatile substances are produced, which can be separated with the excess steam or product moisture. This applies in particular to the torrefaction of lignocellulosic residues.
The innovation in VALORKON is to obtain high-value basic chemicals of high quality (purity > 95 percent) in addition to conditioning the residues to a hydrophobic material. Fraunhofer IGB and Heckmann are therefore developing a process chain with which these valuable substances can be selectively separated from the volatile phase released during torrefaction.
At the same time, the partner Reutlingen University evaluates the technical processes and their value chains on the basis of product life cycles (LCA balance sheet) and environmental influences (LCIA impact assessment) as well as the economic efficiency of the VALORKON biorefinery process chain in comparison to conventional refineries.