[Terrapreta] Pure Organics Vs. Biological Agriculture

[Sean K. Barry]

Hi Allan,

It's about the finite chemical energy in raw biomass.  You can pyrolyze biomass right down to ash, heat, and low/medium BTU producer/synthesis gas.  But, you will leave no charcoal.  Leaving charcoal in the products of the reaction reduces the amount of energy you can take out.  If you can achieve the highest yield of charcoal which is thermodynamically possible, then you release the least amount of energy and/or energy containing co-product gases.  35% fixed carbon yield in the charcoal will leave 60%+ of the energy in the charcoal.  If you expend any external energy in processing or handling the biomass before or after its carbonized, then these expenditures offset the energy obtained and/or the value of the carbon sequestered when you put the char into the soil.

I really think that its about efficiency of the process.  The heat has to be used or harvested as usable energy.  The product gases cannot be simply vented.  They have to be at least combusted or the resulting methane-CH4 component will completely obliterate the benefits of burying all the charcoal carbon you could possibly make.  I think the process of carbonization of the biomass needs to be powered by the biomass energy resource that is in the feedstock and comes out (in part) in the reaction.  It would be better to use the "carbon neutral" energy that is in the biomass, to process the biomass into charcoal, than to apply any "carbon positive" fossil fuels to the task.

Regards,

SKB
  ----- Original Message ----- 
  From: Allan Balliett<mailto:aballiett at frontiernet.net> 
  To: David Yarrow<mailto:dyarrow at nycap.rr.com> ; terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Tuesday, September 18, 2007 10:29 PM
  Subject: Re: [Terrapreta] Pure Organics Vs. Biological Agriculture


  At 9:52 PM -0400 9/18/07, David Yarrow wrote:
  >installing a pyrolysis plant could permit these municipalities to 
  >produce charcoal and biofuel to heat their buildings and power their 
  >fleet of vehicles.

  David- I'm still confused about this. With Danny Day's pyrolysis, 
  biochar remains a semi-precious commodity. I have yet to understand 
  what the limiting factor is...time? I don't know, but from what 
  practical material I've seen offered, I have to assume that pyrolysis 
  is not a very, shall we say, municipal technology currently.

  What say?

  -Allan

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