Pyrolysis is the chemical decomposition of a condensed substance by heating, largely in the absence of oxygen. It is commonly used for organic materials. The process can be self-sustaining as the syngas produced releases heat.

Biochar can be produced by pyrolysis or gasification systems.

• Fast Pyrolysis tends to produce more oils and liquids
• Slow Pyrolysis tends to produce more Syngas and Biochar

The composition of biochar a function of:

• Biomass
• Cellulose, hemicellulose, lignin, & ash content
• Particle size
• Pyrolysis temperature
• Pressure
• Residence time
• Heating rate
• Other

For a detailed description of pyrolysis, refer to:
http://en.wikipedia.org/wiki/Pyrolysis

Cautions:

Please refer to our Disclaimer. Legislation, MSDS sheets and other sources provide information on several topics including the safe handling, proper disposal, and other risks associated with biochar. The following illustrates a few selected cautions for users of biochar, there are additional areas that users of biochar need to be aware of:

• Gasification and conversion of biomass into charcoal is a very hot process. Gasification without complete combustion can occur at temperatures of up to 1000 degrees C.
• Gasification of biomass produces Carbon monoxide (CO), Hydrogen gas (H2) and Methane (CH4). These are all odorless, colourless, and very flammable gases.
• There is also production of non-flammable gases including Carbon dioxide (CO2), Water vapor- (H2O), and some amount of polycyclic aromatic hydrocarbons (PAHs) - entrained liquid in the exiting gas flow, and possibly also soot. ALL ARE EXTREMELY HOT when exiting the pyrolysis reactor/gasifier. All surfaces of such reactors/kilns are EXTREMELY HOT when operating.
• If fresh charcoal, which has condensed volatile matter on it, is exposed to oxygen and sufficient heat, it will re-ignite.
• Charcoal dust and soot can both cause severe respiratory distress.
• Smoke and heat are dangerous. Do not breathe, stay back, and do not touch with bare skin.

The Canadian Biochar Initiative www.biochar.ca