[Stoves] Magh Smoke Burner Stove

[AJH]

On Mon, 9 Apr 2007 15:51:11 -0700, Tom Miles wrote:

>Part of the fixed carbon in the fuel is undoubtedly consumed during
>gasification.

In fact as I have said many times before everything points to the fact
that the bulk of the heat used for the pyrolysis process is from a low
temperature oxidation of the carbon content, you'll see reports that
the char yield falls with the moisture content of the fuel, in fact it
is difficult to sustain a tlud secondary burn when the mc exceeds 30%.

If you look at the post Tom Reed crossposted from John Bertl you will
appreciate why this may be so, also it indicates why the size of
particle a tlud may be limited, because the rate, and hence time
involved, is determined by the amount of heat that can be conducted
into the wood particle, and this is to do with both surface area
(proportionately this decreases with square of dimension) and path
length (increases linearly with dimension).


> What is the carbon conversion efficiency of the TLUD?

I've not managed better than 25% of the dry weight, whereas with a low
temperature retort I've achieved 45% albeit with a <80% fixed carbon,
at a guess.

> Has
>anyone compared the actual amount of char produced in a TLUD with the amount
>of char that would be produced if only the volatiles were burned? 

That's a "how long is a piece of string " question because it depends
on the initial composition of the biomass and the temperature of
pyrolysis (and dwell time the wood is subjected to the temperature)
With wood slow pyrolysis at >450C will yield a char with ~82% fixed
carbon.

AJH