Small-scale, straightforward, inexpensive Biochar production is a valuable component in many grassroots paths to ecological sustainability.
Charcoal production for soil amendment is an attractive option for horticulturists in most growing conditions, if suitable feedstock is readily available. Charcoal is quite stable in the soil, and will sequester the constituent carbon from returning to atmospheric CO2 (the result of natural decomposition) for periods of hundreds to thousands of years.
While elaborate, custom, high-volume systems have been designed and implemented, it is very possible that the greatest quantity of biochar production in coming years will be from small, simple, low-cost, semi-mobile systems assembled in 'DIY' fashion from available materials.
The following project description documents one such replicable model, based on the common 55 gallon steel drum.
Theory
Heat woody feedstock in a low oxygen environment until thoroughly charred:
Option 1, retort method - heat an enclosed volume of feed stock material to optimal temperatures of 500+ degrees Farenheit.
Option 2, rocket stove type - burn the feed stock itself in a low-oxygen TLUD (top loading up draft) stove unit, arresting full combustion.
Design
Components required:
- heat source
- controlled airflow vessel
Materials
Non-combustible; traditionally earth. For workability and weight considerations, steel is ideal.
Operation
Results
Variations
- Folke Günther's "the simplest of the simple" two-barrel charcoal retort