[Stoves] Fabricated Burn Barrel TLUDS

[Kobus Venter]

Paul, Tom, Ron, Alex, Crispin, AD and all,


Paul, you have summarized it well, we'll have to see if the actual is close to the estimate.  Yes I am aware that biochar needs to be light and rigid yet easily crushed and adsorbtion capacity tests would need to be performed. I understand the basics of the TLUD well and have also been referred to Hugh's toucan etc, although admittedly I have never built one like that. As you may have seen from my earlier pictures I needed to process a large amount of biomass feedstock without incurring large transportation costs, i.,e transporting feedstock to the kiln. I was processing about 80 tons of 6 - 8 weeks dry feedstock (invasive aliens aka Working for Water) in my most productive month. Because of the non-uniform nature of the feedstock, TLUD's were not considered and not sure if an upscaled TLUD would have been up to the challenge. In my situation mobility was paramount. The rugged and steep terrain required the 6 kilns to be transported in dissembled
 sections up the mountain side on the back of a LDV (small truck). For biochar end use, once assembled (with bolts, no welding) the Transportable Kiln is fitted with flanges top and bottom (hammered into place), 3 sealable 55 gal drums are lowered and wedged in with central cone to keep them in place. The kiln (along with the 3 x 55 gal drums) are rolled as one unit into position on preselected leveled out terrain. The kiln and conical lid would typically only be rolled 30 or 40 metres every 4 days or so to work through the piles of timber. To extract the biochar the the kiln is pushed over onto its side.

I hereby extend an invitation to anyone on this list to join my Portable Kiln Google Group http://groups.google.co.uk/group/portable-kiln Just ask to join with your reason for joining - if I know your name you probably don't have to give me a reason. I think Ron and Yury are already members from this stove group. 


Have not had much feedback from others because not many have built them yet, but I have posted all my findings and even some kiln plans so everyone gets off the ground with a standard kiln.

Regards

Kobus
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Dear Kobus and all, 

Retort: When 50/50 inner and outer amounts 
of fuel as Kobus has mentioned: the Outer burning XX kg yields zero 
biochar; Inside retort yields 20 to 30& of XX kg, net of 10 to 15% 
of total fuel used. 

(Note: charcoal yields from inside a retort 
of greater than 25 or 30% indicate considerable volatile matter is in 
the charcoal, which is not generally considered good for the 
plants/soils. Beware of charcoal that is 40+% of original fuel weight. 
It will burn in a charcoal stove probably with some limited smoke, but 
is not good as biochar.) 

TLUD: One batch, expect about 20% yield by weight. Nearly double the net weight output, and not needing double barrels, etc. 

Fines
 are a result of size of feedstock. If making biochar, fines are fine 
(pun intended). Or fines can be briquetted quite easily if sold to the 
charcoal market. 

Biggest problem I see with many attempts to 
make TLUD-style barrel-size charcoal makers is the poor quality of the 
lid or top to allow in secondary air that goes to the concentrator hole.
 If this sentence does not make sense to someone, then that person has 
not studied the basics of TLUD operation. 

Users should start 
with small TLUDs (like McLaughlin's "1-G Toucan" out of tincans - plans 
are on the web) so that they know that the TLUD fires CAN and should be 
very clean burning. There is no reason to have smoky TLUDs when using 
200 liter barrels unless using wet fuel or not yet adjusting the TLUD to
 the fuel at hand. 

Paul 
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