[Terrapreta] Char made made under pressurized conditions?

[Sean K. Barry]

Hi Greg,

Spontaneous combustion of volatile matter that has been condensed onto charcoal can occur at room temperature 25º C.  Some VM can re-volatilize (evaporating off the charcoal) and ignite at room temperature.  If it is piled/or bagged after being freshly made the VM on charcoal can ignite in the pile or in the bags.  This is not a lot of oxygen, just some, enough for the an exothermic VM combustion reaction to begin.  The heat released from these reactions ignite the charcoal.  It is like having "automatic" lighter fluids (volatile matter) on the charcoal, that spontaneously ignite the charcoal when it is exposed to air.

If charcoal is cool and allowed into the open air, the combustible VM will likely evaporate off or if its actually combusts in the air will not be able to concentrate enough heat into the underlying charcoal bed to ignite it.

Regards,

SKB

 ----- Original Message ----- 
  From: John G. Flottvik<mailto:jovick at shaw.ca> 
  To: Greg and April<mailto:gregandapril at earthlink.net> ; Terra Preta<mailto:terrapreta at bioenergylists.org> 
  Sent: Saturday, March 29, 2008 9:30 AM
  Subject: Re: [Terrapreta] Char made made under pressurized conditions?


  Greg.

  We would put our hot charcoal into 45 gal drums with a sealed lid to allow 
  cooling then transfer to super sacks.
  At one time the char in drum felt only slightly warm to the touch so we 
  transferred to super sack and stored in our 45 foot trailer. The warm 
  charcoal ignited and burned the trailer full of charcoal + the trailer. Fire 
  department was unable to put the charcoal out so we just had to baby sit and 
  let it burn/smolder until gone. Expensive lesson.

  Regards
  John

  ----- Original Message ----- 
  From: "Greg and April" <gregandapril at earthlink.net<mailto:gregandapril at earthlink.net>>
  To: "Terra Preta" <terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org>>
  Sent: Friday, March 28, 2008 8:01 PM
  Subject: Re: [Terrapreta] Char made made under pressurized conditions?


  > Hmmm........
  >
  > Correct me if I'm wrong, but is it not true that char can still be quite
  > warm, and not burn when O2 comes in contact with it?
  >
  > It is with that in mind that I asked what I did in my previous post - 
  > after
  > all, you didn't exactly say at what temp the char was cooling from did 
  > you?
  >
  > No offense,
  > Greg H.
  >
  >
  > ----- Original Message ----- 
  > From: "Jeff Davis" <jeff0124 at velocity.net<mailto:jeff0124 at velocity.net>>
  > To: "Terra Preta" <terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org>>
  > Sent: Friday, March 28, 2008 19:38
  > Subject: Re: [Terrapreta] Char made made under pressurized conditions?
  >
  >
  >> Greg wrote:
  >>>when all you have to do
  >>> is
  >>> open the reactor door, since the natural composition of air is almost 
  >>> 80%
  >>> ( by volume )?
  >>
  >> If you just open the door the O2 in the air will burn up you charcoal.
  >>
  >>
  >> Kindest regards,
  >>
  >>
  >> Jeff
  >>
  >>
  >>
  >>
  >> -- 
  >> Jeff Davis
  >>
  >> Some where 20 miles south of Lake Erie, USA
  >>
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