[Terrapreta] Clarification about "simple" charcoal devices

[Greg and April]

Correct me if I'm wrong, but if the primary use of the plant, is to produce char you are using a kiln or retort, OTOH, if you are trying to produce syngas, then what you want is a gasifier. 

While a kiln / retort will produce syngas it does so inefficiently ( and at greater expense to the amount of fuel used ) and much the same can be said of a gasifier producing char - it does so at the expense of producing more syngas.

At what point do you draw the line?

Greg H.

  ----- Original Message ----- 
  From: Laurens Rademakers 
  To: terrapreta at bioenergylists.org 
  Sent: Wednesday, April 30, 2008 7:56
  Subject: [Terrapreta] Clarification about "simple" charcoal devices


  Günther, Kevin, Lou, Sean and the others,

  It seems like there has been a misunderstanding about the short "warning" I made against simple charcoal kilns. I didn't intend to downplay anyone's efforts to produce charcoal this way. 

  I made the warning because to me biochar / terra preta is still tied to a very particular context: that of the tropics, close to forests and carbon-rich ecosystems, the destruction of which can be limited by biochar.

  And it is in this context that care must be taken to make the system as efficient as possible. Because your initial biomass feedstock in this environment will often be wood from secondary regrown forest, it is important to make the most of it, else you do not alter the "slash-and-burn" cycle enough and thus your crucial added benefit - that of reducing deforestation - can get lost.

  Efficient does not necessarily mean "large". One of the Biochar Fund's goals is precisely to develop a village-scale plant that uses the syngas for power production (capacity smaller than 20kW), and use it in this specific context.

  Small kilns or retorts made for use by individuals in other (agroecological) contexts might be quite interesting, provided they don't emit too much methane. So I wasn't warning against this at all. 

  Apologies for any misunderstandings.

  Regards,
  Lorenzo


------------------------------------------------------------------------------


  _______________________________________________
  Terrapreta mailing list
  Terrapreta at bioenergylists.org
  http://tech.groups.yahoo.com/group/biochar/
  http://terrapreta.bioenergylists.org
  http://info.bioenergylists.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /attachments/20080430/2eb9780c/attachment.html