Fine-crushing and subcritical water treatment of wood materials suitable for bioethanol production using image processing as intermediate indicators

In the production of ethanol from woody materials through enzymatic saccharification, the prerequisite is the removal of lignin for converting cellulose into monosaccharide. Producing fine-crushed material by a fine-crusher, quantitatively evaluating its shape or surface texture by an image analysis, and subjecting it to subcritical water treatment constitute a new preprocessing technology for the removal of lignin. The image analysis revealed that fine-crushing for exposing the wood fibre results in a high removal of lignin. The exposure of wood fibre increased with increasing moisture content of material. The most favourable fine-crushed material for subcritical water treatment was produced by the use of a small pore size of punching sieve and a high moisture content of material.