The best technique for extracting tannins from wood dust with the laboratory equipment I had available was extraction under reflux. Despite the advantages of extraction with a Soxhlet apparatus, I did not opt for it due to time constraints. Vacuum filtration after extraction under reflux is the most time-consuming part of the process but can be adequately shortened by using larger filters. Of the solvents tested, a mixture of methanol and water was the most suitable because it achieved sufficient extraction of tannins without the additional problems encountered when using water alone. Analysis of the particle size shows that after extraction, the average particle size of the powder is decreased compared to the initial wood dust. The dust explosions occurred only for the wood dust that remained after the extraction with a mixture of methanol and water. No explosions occurred in the raw wood dust and also not in the wood dust residue after extraction with water. From the results, we conclude that moisture in the wood dust used does not have a strong influence on the minimal ignition energy (MIE), but the combination of the use of a combustible solvent (methanol) and the decreased average particle size causes its reduction.
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