Biochar Crusher

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Problem Statement

After pyrolysis, biochar, especially when made from wood, is often made up of larger chunks. These may be too big for use as a soil amendment and will need to be crushed. There is an ongoing debate in the biochar community as to whether these chunks need to be ground down to finer powder or not. Typical biochar processing steps after pyrolysis include crushing, screening, adding liquids (such as fertilizer, e.g. pee and microbes, e.g. from compost tea).

Proposed Solution: Open Source Biochar Crusher

The proposal is to design and build an open source biochar crusher (alternative names: pulverizer, grinder).

Important Considerations

  • charcoal dust, when mixed with air, can lead to a flammable gas-like mixture. The crushing process, especially when moving metal surfaces are involved, can therefore potentially result in a "coal dust explosion"! This could be avoided by feeding wet biochar into the crusher, but may affect the design.
  • char consistency will vary with feedstock: char made from dense wood or nut hulls will have different properties than char made from straw; that said, most chars are soft and easy to crush
  • biochar may be somewhat abrasive


Video collection

https://youtu.be/2YH1UOI8ulg