[Terrapreta] Farm/compost biochar

[Robert Klein]

hi Dick

Your material is not packed enough to work well from the top.  A burn on the bottom will be gravity fed.  And there has to be way to use the burning gases to heat the fuel itself.  It may be that you simply ensure enough air to complete the burn inside the stack.  That is why an earthen kiln as traditionally used works fine while only losing thirty percent of production.

Maybe you measure stack gas temperature and damp it down if it is rising.  Blending the exit gas with the air intake will also help.

I continue to appreciate traditional earthen kiln methods.  Their only flaw is the need for a lot of labor.

You are also demonstrating for everyone, the reason it was impractical to produce terra preta from 100% wood on a volume basis.

regards

arclein


----- Original Message ----
From: Dick Gallien <dickgallien at gmail.com>
To: terra pretta group <terrapreta at bioenergylists.org>
Sent: Wednesday, June 4, 2008 5:41:14 AM
Subject: Re: [Terrapreta] Farm/compost biochar

Hi Max,
My wife is a  ten quid Pom from Redcliffe.  Left Mother England at 4.

Now we're narrowing it down.  On the internal fire, Kevin suggested top lit, with wvo, of which I have over 2,000 gallons plus waxed boxes, spread on top to start it.   What would be the  pros and cons of top lit vs. bottom lit in producing char?  In both cases the gas would be flared off, which would go on for days.  Could that gas eventually be run through a turbo?  
As the first experiment, what if it was top lit without the lid, adjusting air intake from the base.  Because of the 10' dia., suppose it could create air flows without any bottom air.  Can start small, see how the heat is affecting the tank.  There is only the 6" space between the 10 and 11' dia tanks and the roof of the steel bldging. Eventually that has to be insulated, to protect the bldging.  We'll find out right away what damage the heat does to the roof.  Thoughts on 6" of wide open air flow vs. 6" of perlite?    
 
Thanks for your input.  Later, Dick



On Wed, Jun 4, 2008 at 4:26 AM, MFH <mfh01 at bigpond.net.au> wrote:

Dick
 
Thanks for photos of tanks. Serious stuff
indeed.
 
Basically you have two options: (a) making
char the traditional way with an initial fire inside the container and (b)
using an external fire.
 
Given the size of your tanks and limited
cash I'd suggest that the internal method will be the most cost-effective
and simplest to implement. It won't give gas for other purposes but it
will produce copious volumes of char. For an external heat system for example,
there needs to be reasonable insulation of the tank. That alone will be
logistically difficult and expensive.
 
Perhaps other experimenters on list have alternative
suggestions. If we can arrive at the best technique then we can look at the mechanics.
 
Max H
 
 
 

________________________________
 
From:terrapreta-bounces at bioenergylists.org [mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Dick Gallien
Sent: Wednesday, 4 June 2008 12:38
PM
To: terra pretta group

Subject: Re: [Terrapreta]
Farm/compost biochar 
 
Hi Robert,


I agree, we're not picky about the finished product.  Have a few charred
pieces in the field from what I put on with the 425 bu. spreader last week, but
in a garden that I don't have to till, that is no problem.  If a chunk is
too large to fit out the 4' X 4' door, we can just leave it in for the next
batch or two.

As you say,  we're down to that simple system we're fishing for. 
Have any of you seen, heard or read about a simple retort system on even a
small vertical tank?  How is the excess gas separated and vented from that
needed to maintain the charring temp.?
Thanks,  Dick


 
On Tue, Jun 3, 2008 at 4:57 PM, Robert Klein <arclein at yahoo.com> wrote:
Hi Dick

I certainly can appreciate the desire to avoid processing the materials. 
You also have a large enough tank to give it a good shot.

The reason for thinking about packing is that it will control the uniformity of
the end product.  However, it seems that we will end up with a tank full
of oddly sorted and sized material.

The problem as I see it is that the larger chunks will simply not be processed
fully.  but that may also not be too much of a concern.  Screening
will; separate fines, charcoal fuel and the larger bits.  The larger bits
can be thrown back into the kiln as a starter fuel.

The difficulty centers around how do we keep the temperature under 600 degrees
(actually around 400) and then use the production gas to make heat that can be
fed back into the kiln and how do you exhaust the spent combustion gases.

arclein

The tank really allows us avoid worrying about packing, unlike traditional wood
kilns.



Dick Gallien 
22501 East Burns Valley Road
Winona MN 55987
dickgallien at gmail.com [507]454-3126
www.thewinonafarm.com 


-- 
Dick Gallien 
22501 East Burns Valley Road
Winona MN 55987
dickgallien at gmail.com [507]454-3126
www.thewinonafarm.com 


      
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