[Terrapreta] Cost of charcoal amendment to soil.

[Sean K. Barry]

Hi Marc,

You are the third person who I have heard this week say that they are considering the source of external heat required to heating of biomass.  Continuous external heating of biomass is not necessary to pyrolyze the biomass!  Pyrolysis is a self-sustaining exothermic chemical reaction.  All of the energy required to pyrolyze biomass can come directly from and need only come from the biomass itself.  The only external energy necessary to supply is ignition energy.  Once any of the biomass has reached ignition temperature, then a pyrolysis reaction can be sustained by providing limited amounts of air and continuous feed of raw biomass.

I have used an outside wood burning boiler to supply heat for my house for 6 years now.  I burn (entirely combust) about 12 cords of oak logs every winter, between October 31 and April 1, usually.  I LIGHT THAT BOILER ONCE AND ONLY ONCE EVERY YEAR!  I use the energy of crumpling up some newspaper, throwing in a few pine needles and small branches, striking a match, and the chemical energy of a single match to start the fire.  I load the boiler twice a day usually, and it burns, without ever extinguishing for 5 months, solid.  It has done that every year, even in the years when I went on vacation for two weeks in the middle of winter (I have a nephew who I hire to come over to feed, walk, and water the dog and load the boiler).  In actuality, it can be left untended for as long as a week I suspect and it can still contain coals to ignite and continue burning more wood.

Any pyrolysis reaction of biomass, once started (external ignition energy required) can be sustained as long as new raw biomass and limited air are continuously applied.  Even "batch" pyrolysis reactors would only ever need to be set alight once;  you could take one shovel full of hot charcoal from an exiting batch, throw it into the empty reactor, put the new raw biomass feedstock batch on top of it, supply air and keep going.

So, if you really want to use solar heat, then maybe just eat your Wheaties, get a Fresnel lens to ignite paper, then throw it in first when you start up the pyrolyzer.

SKB



  ----- Original Message ----- 
  From: Marc Rassbach<mailto:marc at milestonerdl.com> 
  To: Sean K. Barry<mailto:sean.barry at juno.com> 
  Sent: Thursday, March 29, 2007 6:21 AM
  Subject: Re: [Terrapreta] Cost of charcoal amendment to soil.


  On Wed, 28 Mar 2007, Sean K. Barry wrote:

  > Just to let you others know, I have designed a charcoal making pyrolysis reactor
  > and I am currently working on building the prototype.


  Personally, I'm looking into designs that use solar power to do the 
  heating, with the option of capturing the outgassing to be stored as a 
  fuel source.

  What is your plan for proving the heating of the chamber._______________________________________________
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