[Terrapreta] OT Fiber re-inforced ceramics

[rukurt at westnet.com.au]

Hi AJH,


AJH wrote:
> On Fri, 25 May 2007 09:23:38 +1000, rukurt at westnet.com.au wrote:
>
>   
>>> You may well be right about the temperature, but in the modified TLUD
>>> setup I've been experimenting with temps don't seem to get *that* high.
>>>       
>
> Which temperature are you referring to? The temperature of the
> pyrolysing front ( which seems to be around 500-700C) or the
> temperature of the secondary flame? This latter is harder to measure
> as thermocouples notoriously under read an open flame because of
> radiative cooling.
>
>   
Not the faintest idea what temps are reached. I've got a 55liter garbage 
can with a few holes drilled in the bottom for primary air, and a piece 
of downpipe mounted in the lid. Fill it with chipped bamboo, a few 
sheets of paper in the top, light the paper, put on the downpipe for 
some draught and away it goes. attempts to light the smoke have been 
unsuccessful so far, the char produced seems to be quite good, exposing 
it to a gas flame produced no additional smoke, so it seems to have been 
pyrolised quite well.
I'm writing all this up, with piccies for a website, but further 
experiments, to finalise that have been held up by unseasonal wet 
weather. More later. The galvanising on the outside has a thin layer of 
ZNO on it and this turns yellow when it gets hot and lets me know where 
the flame front is. No other temp readouts available.

>>> The extra char consumed might be a case of 6 of one and half a dozen of
>>> the other. The clay bits would need firing one way or the other and
>>> that would need a source of energy, though I suppose the gas from the
>>> TLUD could be used to fire a suitable kiln.
>>>       
>
> Yes I think this could practically be arranged. The offgas is a
> reasonably high calorific value, from dry wood, probably twice that of
> the producer gas and pyrolysis products from a full gasifier but at a
> few hundred degrees lower temperature, so I would expect to see
> temperatures above 1000C if the air ratios are near right in a pre
> mixed flame.
>
> It will be somewhat lower than a pure wood in air fire which IIRC
> peaks at about 1600C.
>
>   
No doubt.

I'm not doing this as a scientific experiment, it's a "suckit and see" 
experiment to try out the concepts. Not burning the smoke isn't a 
problem, the nearest neighbour is half a kilometer away and we don't 
have weather inversions here.

Kurt