[Terrapreta] Earthen Kiln Conjecture

[Robert Klein]

Hi Sean

I do not know where you get your information from, but it would behoove you to read the various postings that I have made on this subject here and on my blog where I tackle every sub issue that I can.

I cannot think of anything more important than understanding how it was possible for the Indios with a stone age tool kit to produce biochar in the form of powdered carbon no less!  They clearly produced millions of tons while we so far have produced a few hundred pounds or so using drums and the like.  Obviously we are idiots.

And they did not do it by using much wood.  The little they used is still there to see and it is not much.  Charcoal does not powder itself without mechanical intervention.

You also continue to rant about methane production from such a kiln.  Firstly, if you attended your grade eleven chemistry class, you would have discovered that methane heads straight to the troposphere and is consumed there somewhat like tossing salt in the ocean.  In any event, most will be consumed by the chimney and if any actually escaped, one merely lights a match.

By the way, methane atmospheric signatures are not maintained over the oceans confirming the rapid removal of the methane to the troposphere.  Get off this hobby horse.

You also ask about sourcing corn stover.  You obviously know nothing about corn production.  Each acre of corn field will produce most of ten tons of corn stalks that must be pulled out and burned regardless releasing all the material as co2 back into the atmosphere.  Reducing these ten tons of corn stover to biochar is a small increase in the actual workload already necessary.  In fact one would expect the oldest man who no longer has the strength to pull stalks all day to do the packing meaning almost no diversion of labor.

This simple process sequesters at least a ton of carbon per acre each season  that it is used.  A mere fifteen seasons and you have over fifteen tons per acre.

Much more interesting however is the fact that this earthen kiln design will also tend to capture a lot of the heavier volatiles in the earthen shell so that we actually have a blend of combustion products mixed into the soil.  This is not as specific as producing pure activated charcoal but I think that having a wide range of such molecules maximizes the possibility of results.

And we need to properly study such a product, not an artificial one blended with only one type of carbon.

An industrial kiln design such as described in my blog will typically destroy all the volatiles and leave only the carbon.

Have a good day

bob


----- Original Message ----
From: Sean K. Barry <sean.barry at juno.com>
To: terra pretta group <terrapreta at bioenergylists.org>; Robert Klein <arclein at yahoo.com>
Sent: Monday, April 14, 2008 2:22:12 PM
Subject: Re: [Terrapreta] Earthen Kiln Conjecture

 Hi Robert,
 
Again with this post.  Whatever the Indios did to make charcoal out of 
whatever they used DOES NOT MATTER TODAY!  When are you going to grasp 
this?  Recommending to make charcoal in earthen kilns (in the open air) 
made from corn stalks is a bad idea.  There is no way to do this without 
massive releases of Methane-CH4, which has been discussed ad-nauseum with you as 
a significant potential problem with this plan.  Also, just like there 
isn't enough corn grown in the world to make enough ethanol to supply the 
world's thirst for transportation fuel, there IS NOT ENOUGH CORN STALKS IN THE 
WORLD to make the amount of charcoal we need to form enough Terra Preta and/or 
make any kind of difference on agricultural food production or global climate 
mitigation.
 
Move on.  Your past one idea (Earthen Kiln Conjecture) is too limited 
and problematic to be a solution or of any value to us, Robert.  That's my 
opinion and widely held in this group, I think.
 
Best Regards,
 
SKB
 
 
  ----- Original Message ----- 
  From: Robert Klein 
  To: terra pretta group 
  Sent: Monday, April 14, 2008 1:14 PM
  Subject: [Terrapreta] Earthen Kiln   Conjecture
  

Ihave reposted an article by David Bennet with Lehmann on Terra   Preta publishedin 2005.  This outlines the most criticalinformation as   well as describing the original scope of the Indian civilizationitself. It is   at:http://globalwarming-arclein.blogspot.com/2008/04/earthen-terra-preta-kilns-and-pollen.htmlAgainthis   lays out the limiting factors and fully supports my earthen kilnconjecture,   particularly the following quotation.“There has been some pollen analysis. It   suggests manioc and maize were
being grown 2,000 to 3,000 years ago. In the   pollen bank, these crops didn’t
pop up sporadically but in large   numbers.”
Ihave also polished my description of the protocol and am   activelypromoting  field trials.Firstly,the maize or corn exists in an   environment that mitigated against its use forpurely food production.    There werealternatives far better suited. to the non terra preta environment,   startingimmediately with manioc which I think is a rainforest friendly plant.   Secondly,the only viable source of meat protein to these peoples at this   populationdensity was through fish.  Withoutconfirmation, a pond with   tilapia makes great sense. It was a staple for the Maya.The waste from the   daily meal could be readily folded into any growing seedhill.  Human   waste could simply have beenburied in the field itself avoiding any   storage.  This is common practice to this day. Themaking of the earthen   kiln is no more difficult than uprooting the dehydratedcorn stalks after   harvest and properly stacking them to form an earthen walledkiln with a wall   thickness
 of two to three root pads
 and an interior of tightlypacked   corn stalks.  Obviously, any otherplant material, including wood can be   built into the stack as available.  The earthen wall nicely restricts air   flowduring the burn phase and lends itself to optimization by changing the   wallthickness.  It also minimizes the amountof human effort needed which   is through the roof if you are attempting to coveror bury a ten ton pile of   stubble or branches. Thisgives you a kiln with vertical earthen walls and a   possibly domed top that canbe easily covered with earth.  Again,field   trials will optimize this protocol very easily.  The kiln could be   squared off or perhaps evencircular though unlikely. The only tool to this   point is a strong back ortwo.  We have gathered several tons ofcorn   stover over perhaps an acre of land with only a little more effort thanthat   annually required to clear the field and burn the waste. Nowwe must fire the   kiln.  The easy way isto take
 a clay lined old basket
 and fill   it up with coals from a woodfire.  Carry this ember charge to thecenter   of the kiln top and tip the charge onto the exposed center and place thebasket   as a cap to the newly forming chimney. 
More clay may be necessary to widen   the chimney cap.  Throw more earth on top of this to preventbreakout of   the fire.  Keep throwingearth on any breakout points that start. 
The   chimney will serve to burn all the volatiles produced as the hotzone expands   to fill the collapsing kiln until they are exhausted.  Thereupon the hot   zone will cool off leavinga blend of biochar, ash and earth and some root ends   for the next kiln.  And yes, we should have a lot of fired clay.   Thebiochar itself will be a range of nonvolatile combustion products that   willrange from even dried vegetation to activated charcoal following a nice   bellcurve.  The material can be then gatheredin baskets and redistributed   into the field onto the seed hills again reducingwastage and effort. Irealized   originally that the only ancient plant that could accommodate a highenough   volume of terra preta production was good old maize.  It just seemed an   unlikely option fortropical rainforests. That is when I started looking for   references to thepollen record.  The article by DavidBennett and Lehmann   is one of those reverences that then emerged.
 Iwould like to get a   full
 spectrum of the pollen profile since it seems verylikely that   while the fence rows held the food trees, it seems more likely thatthey also   used a variation of the three sisters using some form of   convenientlegume.  Squashes also, of course, butnot nearly as important.   Thekey point of all this is that a family can convert a field into terra preta   inone short season, allowing them to repeat the process thereafter as   necessaryuntil the field is completely transformed to depth.  Today, we   can do the same thing using shovelsand a garbage can   lid.




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