[Terrapreta] torrefaction vs. carbonization

[Sean K. Barry]

Hi Gerrit,

Charcoal is hydorphobic.  Charcoal is inert and does not alone absorb nutrients.

Regards,

SKB
  ----- Original Message ----- 
  From: Gerald Van Koeverden<mailto:vnkvrdn at yahoo.ca> 
  To: Nikolaus Foidl<mailto:nfoidl at desa.com.bo> 
  Cc: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Saturday, December 08, 2007 4:20 PM
  Subject: [Terrapreta] torrefaction vs. carbonization


  Nick,


  I had to look up what torrefaction was:


  "Torrefaction is mild pre-treatment of any biomass (including bamboo) at a temperature between
  200 and 250° C. During torrefaction the properties of bamboo undergo changes, wherein the end
  product has much better fuel quality compared to biomass for combustion application. The
  decomposition reactions during this process results in bamboo becoming completely dry and
  loose its tenacious structure, also the hygroscopic nature of the biomass is changed to
  hydrophobic material. Besides this, the process increases the calorific value of the end product.
  The actual weight loss in this period would be about 20 to 25 % whereas 90 % of the energy of
  the parent dry material is preserved in the torrefied matter. The combustion process of this matter
  has less problematic volatiles and hence the process is closer to that of charcoal. It can therefore
  be used as an alternate to charcoal in many applications. It also makes the material immune to
  attack by fungi. Hence long term storage without degradation is possible."


  Based on 15 minutes of research, it doesn't look promising.  It would seem that this super-drying of wood makes it hydrophobic...and if it stays that dry in the soil, it would be difficult for nutrients to move through a soil solution into it.  Moreover, it doesn't sound like it is conducive for a 'fungal' bridge between itself as a microhabit for microrganisms with the soil;  in char mixed with composting material, the char actually becomes a microhabit for fungus...
  However, this is only speculation.


  How closely have you examined the torrefied wood you have found in the soil?  Does it 'house' microrganisms?  Has it absorbed soil nutrients?  Or is it merely an inert material taking up space?


  gerrit






  On 8-Dec-07, at 2:21 PM, Nikolaus Foidl wrote:


    Dear all!


    My charcoal costs at a charring efficiency of 42 % is around 35 US$ per ton
    Charcoal. Now after analyzing 15 year old soil where huge amounts of forest
    where simply burned and charred. Now excavating I find huge amounts of only
    torrefied wood pieces which as well did not degrade, like the charcoal
    chunks.
    Now looking at this and if torrefied wood would do the same as is charcoal,
    why not save a huge amount of additional CO2 and just torrefy the stuff and
    mill it and then burry it? Cost per ton would drop to half, CO2 taken out of
    the atmosphere rise by 50 to 70 %.
    Just an idea but maybe worth to be discussed.
    Best regards Nikolaus






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