[Terrapreta] Farm Scale Batch Charcoal Furnace for Homestead orFarm

[Sean K. Barry]

Hi David Stewart,

I've seen your last few posts and have been reading along to find out more of what you are interested in.  Pyrolysis of biomass for the production of charcoal, heat, and/or combustible fuel gases is very interesting thermodynamic process.  The first thing to keep in mind is that there is a finite amount of chemical energy in the biomass.  Desiring to produce all of charcoal, heat, and combustible fuel gases at usable levels necessarily requires more biomass fuel.  Secondly, the configuration of the pyrolysis process (top-load-up-draft, down-draft, fluidized-bed, etc) and management of the thermodynamics and chemical stoichiometrics is critical to the efficient operation of the device.

There exist few devices that are even close to fully automated.  Take a look at the Community Power Corporation website (http://www.gocpc.com/<http://www.gocpc.com/>) for an example of a $500,000 15kWe biomass fueled generator.

Regards,

SKB
  ----- Original Message ----- 
  From: AJH<mailto:list at sylva.icuklive.co.uk> 
  To: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Monday, April 07, 2008 12:10 PM
  Subject: Re: [Terrapreta] Farm Scale Batch Charcoal Furnace for Homestead orFarm


  On Mon, 7 Apr 2008 10:12:06 -0500, David Stewart wrote:

  >No. Didn't mean to take it off list, just new to the whole concept and
  >wasn't sure that I would be responding to you directly if I put it on
  >list.  Please feel free to post anything you write on the list and I
  >will endeavor to do the same.

  OK I've copied the conversation to [terrapreta], although it's all a
  bit upside down now.
  >
  >I'm guessing that most of the wood would be "lop and top", if that
  >means branches and the like.

  Then you'll need to decide how to get that down to a size that will
  fit in the kiln, bearing in mind bigger pieces take longer to dry and
  pyrolyse.
  >
  >On Mon, Apr 7, 2008 at 8:42 AM, AJH <ajh at sylva.icuklive.co.uk<mailto:ajh at sylva.icuklive.co.uk>> wrote:
  >> On Mon, 7 Apr 2008 07:28:07 -0500, David Stewart wrote:
  >>
  >>  >About 200,000 btu is the size of the furnace that I've anticipated for
  >>  >the house.
  >>
  >>  I think 200k Btu/hr is about 60kW(t) so fairly modest. Also oil and
  >>  gas fired furnaces tend to run for shorter periods, so you can have a
  >>  wood fired device running more nearly constantly and have a smaller
  >>  power. Having said that I'd guess we could have a pyrolyser no more
  >>  than 1.2m by 1.2m (4' by 4') for the actual reactor. With half the
  >>  energy being left in the char this equates to about 23kg/hr (50lb/hr)
  >>  of bone dry wood.
  >>
  >>
  >>  >Fuel would be primarily wood.  It's what we have in abundance in the NH.
  >>
  >>  Sizes are an important consideration, would it be solid billets,
  >>  lop&top or woodchip?
  >>
  >>  Did you mean to take the conversation off the terapreta list?
  >>
  AJH
  >>
  >>


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