[Stoves] Limiting factor for secondary burn?

[psanders at ilstu.edu]

Frank,

You addressed your message to me, but I cannot see any way to assist you.  You
are not doing TLUD, and TLUD is the nature of the Reed-style woodgas 
process. So do not expect a similar result.  Even without the very 
small size and the
use of a glass container, what you are doing should NOT function.  (At least
not in any way that I can understand as of now.)

It is true that traditional updraft gasifiers do work.  And the gas-producing
fire is at the bottom.  But they are burning char at the bottom.  And unless
the heat is very great (in order to pyrolyze some of the raw fuel above 
the hot
char), it does not give you usable gases at the top.  And in your very
small-size experiment, the pile of raw fuel is (relatively speaking) enormous
above the very small bottom fire.

Please note that so many many fires and stove configurations are lit at the
bottom.  Bottom lighting is NOT the single criteria for making a 
gasifier, even
if you confine the fuel into a glass tube.

I (via my company Chip Energy) do have an bottom-fired updraft gasifier (see
http://www.chipenergy.com/furnace.htm ).  But it, even with its larger 
size and
high-heat of operation, cannot be ignited in the way that you are trying to do
your small-scale experiment.

If your white gases are actually a cloud of water vapor (which I expect they
are), they will never ignite.

You mention that "understanding woodgas" is your motivation.  So I do not know
how you got onto the track that you are following.  Tom Reed has done the TLUD
woodgas experiment in glass tubes, but he lights it at the top.  That is a way
to understand woodgas creation and combustion.

Paul

Quoting frank <frank at compostlab.com>:

> Dear Paul,
>
> I got a chance to try a few more runs using cardboard as a starter 
> and very dry wood chips (< 2 cm) for the fuel
> .
> I find the O2 is hard to get to 0 as Crispin suggested without the 
> burn (glow) going out. I think the problem is that I have a flat  
> cross section of burn and if it is not completely burning across the 
> horizontal some un-used air goes past. I am thinking I need to funnel 
> down the location of the burn so all the air passes through the glow. 
> I am thinking I will need a weak spring pushing on a perforated plate 
> to make sure the fuel is pushed to the bottom as it is being used up 
> where the burn is.
>
> As I said before the top of the glass '1/2 stove' is just warm and 
> the gases are room temperature and white. Will these gases at room 
> temperature ignite? Or do they need to be close to the primary burn 
> and hot?
>
> I am thinking I have a BLUD wood gas producing unite. I have left out 
> the secondary burn  and hope to get to that when I get the primary 
> burn adjusted to do what (I think) it should. Is this what i am 
> doing??
>
> Thanks
> Frank
>


----------------------------------------------------------------
This message was sent using Illinois State University Webmail.