[Terrapreta] biochar and sugarcane growth (reply to AD Karve)

[Ron Larson]

Tom, AD,  terrapreta list members:

    I add a few questions to your message of last night:

  As others have remarked the trash (leaves) contain high concentrations of nutrients that make it difficult to burn in industrial boilers. These are appropriately retained in the char in the ARTI process, which would make a good agricultural char.       [Tom -  This is possibly the first time I have heard this - or are we talking about the presence of some components of ash that can generate a "glassy" residue?   Is the problem avoided in all pyrolysis approaches?   
      This is way off topic - but I saw a "kiln" (right word?) once in Uzbekistan solely dedicated to combusting (not pyrolyzing) a particular difficult-to-harvest mountain-top plant, whose composition led to "pockets" of a ceramics glaze (with very nice properties - with almost no further processing).  What is a combustion problem for many was the whole point of their operation.  (They are doing it now only to honor their village traditions  better glazes are available at much lower cost.)]
   

  We need to think on two levels in this discussion: (1) the rural smallholder, and (2) industrial production.

   

  Charcoal made from leaves and applied directly by the rural smallholder is one economy. The example is the ARTI kiln.   [RWL:  I have been thinking also of some rural small-holder pyrolysis of bagasse - perhaps in charcoal-making stoves - but perhaps even without that logical by-product use.  I don't believe we have to assume leaves only at the household level.]

   

  Charcoal made by processing the bagasse residue after processing the cane at the mill is another economy. Or, collecting the trash for conversion to charcoal at the sugar mill is an industrial economy distinct from the smallholder. The examples are the processes converting 100 tpd or more like Dynamotive, Renewable Oil Corporation, Ensyn, EPRIDA, and Carbon Diversion Technologies (Antal). [RWL:  Agree mostly.  But this large-scale conversion may prove to be best with both bagasse and the leaves.  I think it probably sub-optimum to leave the leaves (no pun intended) in the field for burning (as seems to be practiced worldwide).  The mill I visited a few weeks ago in Australia will for the first time ever be leaving no leaves in the field (I think in large part because of objections to the uncontrolled combustion there)!

   

  In recent years large gains have been made in India in converting bagasse to heat and power at the sugar mills. And there is pressure at all (900?) mills around the world to process the trash. There are also pressures and incentive to convert the bagasse and/or trash to liquid fuels. We have worked on industrial projects involving both those processes.  [RWL:  Tom - do you know of ANY of those (besides the two I learned of in Australia about to start), who are operating the electrical side of the sugar mill operation year-around?  I think the mill economics should much improve with that mode of operaton - and experts I have talked to say this is not being done to their knowledge - and of course have confirmed by experience that no-one in the mill business is pyrolyzing anything.

      I like the alternative conversion of the bagasse to liquids (either cellulosic ethanol or fast pyrolysis) and know of companies doing both with bagasse.  But I know of none who are emphasizing charcoal - except as a minor byproduct.  Have you worked with any along those lines?  (For anyone wanting to try it, I recommend Tom as the best person to start with this discussion.)

   

  Initially there may be more incentive for a sugar mill to make heat and power from bagasse than to make charcoal. There may not be enough value for the mill to bring in the trash from the fields for converting it to charcoal. That is where there should be an opportunity for small producers like JFBiocarbon, BEST Technologies, or char from the modular oil producers like Advanced Bio Refinery, Renewable Oil International or Agritherm.  [RWL:  Yep - the incentive is not there yet - but to prove there might be an appropriae incentive is the reason you started this list.  

      I think/hope that the world will soon discover (with the help of people in the field like AD and yourself) that the climate and soils benefits (neither now being considered in the sugar business apparently) of charcoal will exceed the value of any other form of their waste conversion, and especially of combusting leaves in the field.  I agree there is a role for pyrolyzers at all scales.  Fortunately, AD is an expert on this at the family level as well.]

   

  See: http://terrapreta.bioenergylists.org/company



      Tom - you are doing a great service by advertizing the existence of these pioneering firms!      Ron]

   

  Tom

    

   

     
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