On Apr 3, 4:53 pm, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
wrote:
> ...
> I do not think they have found anything particularly novel
> or exciting. Nor are they about to commercialise their process in
> Coevorden, that plant has nothing to do with their lab scale
> dabbling.
Thank you for clarifying this important point.
> Nor do I see any evidence that this particular pressure cooking
> variant would make biomasss especially resistant to biodegradation
> compared to other carbonisation methods, or any reason why they the
> term biocoal should suddenly be restricted to their product, when it
> was used by others long before they got into this business.
But it does make for some confusion, yes. My understanding of their
pressure cooking method is that it is possible to produce anthracite.
Surely this is not possible via pyrolysis or torrifaction? Not even
bitumin?
> Not to say that there aren't differences in biodegradation behaviour,
> but you can't just point to a distinction between "charcoal" and
> "coal", say the former is degraded over time and the latter isn't, and
> then losely associate a particular carbonisation method with "coal"
> and another (all others???) with "charcoal" and declare that therefore
> one carbonisation method is superior to the other. That logic doesn't
> work.
Why not? We know that natural coal lasts for millions of years in the
ground while naturally produced charcoal appears (so far) to last for
only thousands, sometimes a few tens of thousands of years. Of
course, torrifaction does not naturally occur (in any quantity) so
there is no data.
Since hydrothermal carbonization was done specifically to produce
actual coal, very much faster than nature does it, it appears to be
the most secure way to produce a carbonaceous material for permanent
burial of carbon. I doubt that it is more expensive to produce in
quantity than biochar or torrified wood. In principle any source of
biomass could be used. [The process is rather similar to hydrothermal
liquification. There is a demonstration plant in The Netherlands
(Amsterdam, I think) which uses municiple waste water (clarification
sludge) to produce high-quality biodiesel via hydrothermal
liquification.]
With regard to natural coal persisting due to an anerobic environment,
I now do not think that is a requirement. I know of a site with
anthracite only a few centimeters under the soil. Paleoamericans used
the anthracite for heat, leading to a very wrong radiocarbon date!
Regarding using biochar as a soil amendment, all the trials to date
suggest this is a winner. Except if the goal is long-term storage of
the carbon in the ground. Actual field experince shows that about
half returns to the active carbon cycle after a few years. The other
half persists for lengths of time which may depend upon the soil type,
etc. The Amazoniam Terra Preta soils appear to provide carbon dates
of up to 7000 years, but the other data is all from naturally occuring
charcoal. That data suggests to me that soil type may well play an
important role. In any case, I know of no reports in the geological
literature of any naturally occuring charcoal in srata more than a few
tens of thousands of years old.
Despite our differences of opinion, I greatly appreciate your informed
comments on this thread.
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