This waste stream is connected to the technial Circular Solution "Waste wood for the production of biochar (activated charcoal from renewable and sustainable resources)".
Due to the different origins, waste wood can be contaminated to varying degrees with foreign substances (contaminants). For this reason, in the German Waste Wood Ordinance waste wood is divided into four categories:
The in-going waste flow in this case study is limited to the quality categories A1, A2 and A3. The ingoing waste wood needs to be pre-processed (cut into smaller pieces) with a so-called wood shredder/clipper in order to be used as a secondary raw material. Also, contaminants (e.g. metals and non-ferrous metals) need to be partially removed.
The exact shape and form of the pre-processed input material depends on the size of wood gas power plant.
Figure 1: Fotos of chipwoods used as input materials.
Size and shape of the waste wood chips are size G30 and G50 according to the Austrian Norm ÖNORM M7133, see
Table 1. Table 1: Fractions and sizes of wood chips according to ÖNORM M 7133.
Woodchips are small to medium sized pieces of wood, including bark and fines, formed by cutting or chipping larger pieces of wood such as trees, branches, logging residues, stumps, roots, and wood waste. Also contaminants such as nails, brackets and braces can be included.
Depending on the quality category the waste wood will be either recycled to chipboards or used for energy recovery.
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