[Terrapreta] (no subject)

[Sean K. Barry]

Hi Robert,

Last night when I was writing to you about methane (CH4) emissions from "open-air" charcoal kilns, I made a small mistake.
I said that open pyrolysis can retain as much 25% of the original carbon from the biomass, venting the other 75% as CO and CO2.  I should have said that "open air" pyrolysis can retain, as charcoal, as much as 25% of the original mass of the biomass feedstock.

The amount of carbon by weight in the raw biomass is originally ~40% and charcoal is 93-95% carbon, so maybe up to ~63% (0.25/0.40 = 0.63) of the original carbon can be retained (as fixed carbon) in the charcoal.  Nonetheless, releasing the ~2-3% methane-CH4 content of the "producer gas" will still significantly outweigh the benefits of sequestering that carbon as charcoal put into soil.

Regards,

SKB
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