[Stoves] Limiting factor for secondary burn?

[frank]

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



 



Paul S. Anderson wrote:

> Dear Frank,
> Quoting frank <frank at compostlab.com>:
>
>> 1) what should the small fuel look like after the primary burn (I have
>> not set up for the secondary burn yet)?  Should the sticks look like
>> sticks - only black?
>> 2) should the glow move up the pri. fuel body (BLUD) because the
>> structure of the fuel is maintained (only black) or should the fuel drop
>> down due to additional breakdown?
>> 3) Is the goal to have the tar go into the sec. burn? or is it better to
>> trap it in the fuel body and keep it away (only letting the lighter vol.
>> organics go into the sec. burn)?
>> 4) It you get tar in the pri. burn is that indication of a burn that is
>> too hot?
>
>
> What you have ask indicates to me that you are not doing a TLUD nor a 
> woodgas
> unit nor a gasifier.  What is the basis for the design that you are 
> using? Perhaps I do not understand the nature of your experiment.  
> Please explain.
>
> Paul
>
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>

-- 
Frank Shields
Soil Control Lab
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