[Terrapreta] % yield of charcoal

[Ron Larson]

Duane, AD, Terrapreta list members:   See short inserts below on your questions of last night.  You asked AD:
  1. Would that 33% be 33% by weight of the original dry mass? Would the original dry mass be fairly typically about 50% carbon? Does that mean some 66% of the original carbon in the biomass becomes char? 
         [RWL1:  For our purposes,  I think the answer to all three questions is "yes".  Bone dry biomass  (average) is not far off from one carbon atom and one water molecule - so with C at an atomic weight 16 and water at 18 - you can see why 50% is close.  Tom Reed's BEF site I think contains detailed data on the molecular composition of different biomass species.  Ash content screws up the simple computation.]

  2.  Would it be possible to adjust the oven and retort process possibly with some external energy input so the pyrolysis gas is mainly hydrogen and water with minimal carbon bearing gases? 
      [RWL2:  a.  Mike Antal's process seems to come close to this.  I have not yet understood Mike's work, but it looks very promising to do what you suggest.
      b.  The initial work of Danny Day (Eprida site) was based on producing hydrogen with char as a by-product.  Look up papers also containing the name of Danny's DoE/NREL monitor Dr. Bob Evans - who had the initial hydrogen interest and sought out Danny/Eprida.  
      c.  I also have hopes that some solar "external energy input" will help in simpler oxygen-free conversions - by avoiding the nitrogen that comes along with any required oxygen.  So far, I have only found a few hints of past work along these solar lines, but think there is some past work.
      d.  Mike Antal was dismissive of work that received brief mention here on "TP" on April 18 sent in by John Cowans, with a European apparently renowned researcher reporting decomposition of biomass in the presence of a catalyst and modest temperatures and time into only water and carbon (no hydrogen and no char).  Maybe you can research this further following the lead at http://www.dw-world.de/dw/article/0,2144,2071791,00.html.  Maybe there is some role for catalysts in other ways even if that work was bogus.

  3.  Could the yield of char be increased to something approaching 100% of the carbon originally in the biomass?  The goal, perhaps silly, would be to maximize the carbon sink potential of the process.
      [RWL:  I encourage your further work along these lines - the goal is not silly.  However, even if we don't achieve 100%,  we must find ways to capture for productive purposes the released carbon.   The reason your suggestion is important is that there are many places (like deep in forests) where there just isn't going to be much of a way to capture those "lost" carbon atoms.  Even the char may have to be left behind.  Traditional charcoal production is even worse - putting out gases like CO and methane that are even worse from a climate standpoint than CO2, because they are only vented - not flared.]

  Ron


  Duane


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