[Terrapreta] Long term durability of Low Temp Chars

[Sean K. Barry]

Hi AJH,

I've read, from work by Michael J. Antal, at the University of Hawaii, that the maximum theoretical amount of carbon, which can be retained in charcoal, after pyrolysis of biomass, is somewhere ~30-40% by weight of the feedstock biomass.  Achieving that is difficult and usual yields are more likely around 25% on a weight by weight basis charcoal/dry weight biomass feedstock, with charcoal being ~93-95% carbon.  Michael is a member of this list and he may be able to answer your questions better, so try to contact him  (maybe he will see this post and respond to you directly?).

Regards,

SKB
  ----- Original Message ----- 
  From: AJH<mailto:ajh at sylva.icuklive.co.uk> 
  To: Sean K. Barry<mailto:sean.barry at juno.com> 
  Sent: Thursday, May 17, 2007 9:56 AM
  Subject: Re: [Terrapreta] Long term durability of Low Temp Chars


  On Tue, 15 May 2007 16:21:51 -0500, Sean K. Barry wrote:

  >I don't think that it is doubted that anything less than a very high percentage of the original charcoal matter that was put into the soil over some thousands of years ago, is not still there.

  Nor I, I'm fairly confident all the fixed carbon will be there still
  but when the claim is made for carbon credits and there is ~18% of the
  weight in carbon-oxy-hydrogen compounds how much weight of carbon is
  sequestered?

  AJH


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