[Stoves] air for gazification

Sat Jun 9 17:54:50 EDT 2007

Dear Kevin,

At first thanks, that you gave me the PERSONAL TOP SECRET INSIDER
INFORMATION. :-)

Building on that, I want to tell you other details.
But let me start by Adam and Eve.
Sometimes when I try to get a very good wood-burn by my tincanium-plays, I
get more sooth than expected, or simply said: The burn then is worse than
with less effort (done) to get better burn.
Naturally there must be more secondary air, but how about reducing the
primary air; and __not__ to preheat the primary air, which I formerly
thought to be helpful.
This turned out to the idea, to run a simple (-not yet constructed-) T-LUD
with sharply separated primary (not preheated!) and secondary (preheated!)
air.

I want to get primary air in variable, but exact amount. 
Familiar with rotameters in anaesthesia I think, they are good to play with.

-Beside the advantage of measurable quantity within definite time, I see
another advantage in the high pressure before the inlet-valve, which
guarantees, that the chosen fresh-gas-flow is maintained even by different
flow-resistance of the wood-fuel-stack. (-When I remind right, Jeff Davis
wrote about this problem, and how to solve. I have been off line for a long
time, and I am now reading spontaneously in the passed stoves-postings)

In anaesthesia-equipment, the volume-difference of fresh-gas, caused by
different system-pressure behind the rotameter is not big during an
artificial "breathing-cycle" which is normally about from 0cm water-column
(breathing out) up to 25cm water-column (breathing in)(in special situations
40cm water-column and more).

I want to bite the burning problem into two separate parts (being aware that
they are not independent!) 
-And that dividing is by my opinion the key of such clean burning in the
gasifiers!-
For the primary process: 
Gasification: I can determine how much air is the "workable" minimum and
maximum which makes sense by a given cross-square of the griddle/stack?
And therefore it is interesting how much "smoke"(=kw-gas) I can produce with
how much litres fresh-air, without to starve the gasification process or to
turn the gasification-process more or less to a definite total burn in the
gasification area.
That was the interesting "part"-amount of air, I hoped to find the numbers
somewhere.
Possibly Tom Reed knows more about that, but it could be one of the
construction-secrets of his Camping-stove; (because it was so hard to find
out) 
-As far as I had read about the development of Tom Reeds Camping-stove
stove, the experiments where done with measuring the air-pressure for the
forced air and not by measuring the air-amount per griddle/stack
cross-square.
And I can imagine, that this made a lot of trouble to get a solution because
this is like a "turning all the different setting-buttons" at the same time.

Paul Anderson could be interested in that too, but natural draft
(only/pure/simple -all those attributes are right) does not allow to get
exactly primary-air-volumes.
-But why not to do, as I propose, a T-LUD-burning with only forced (exactly
dosed "high-pressure") primary air? 
-And then let us look for the most
comfortable/simple/economical/clean/agreeable solution(-s!!) for the
secondary/gas burn.

My assume:
-I expect for a normal 10cm diameter can to play with a power of about 1kw
(That is roughly: 1kw / 80square-centimetres)
-To begin with 1/2 the amount of the total burning air (I think or even
hope, it will be less for merely smoke making)
In cifers:
1/2 of the total amount is: 20 cubic feet of air per hour, 
that are 566.339 litres per hour,
or 9.439 litres per minute, or 157 millilitres per second.

- 10 litres per minute are in the upper range of a normal oxygen-rotameter
in anaesthesia-equipment. Such a rotameter would fit.

- Transformed to the square-measure-unit 1 square-centimetre: 0.125 litres
per minute.

Please don’t be angry, that I will include the stoves-list-community into
our PERSONAL TOP SECRET INFORMATIONS!

Meanwhile I am looking for the suitable rotameter, and the fittings to
connect with the compressor.
When I will have these things ready, I will cut some cans, to make tests.

I will keep you informed, though it is smallest-scale and a sort of
lowest-tech.  :-) 

Let us have fun!

Best wishes!

Martin

> -----Ursprüngliche Nachricht-----
> Von: Kevin Chisholm [mailto:kchisholm at ca.inter.net]
> Gesendet: Samstag, 9. Juni 2007 01:59
> An: boll.bn at t-online.de
> Betreff: Re: [Stoves] air for gazification
> 
> PERSONAL TOP SECRET INSIDER INFORMATION!!! :-)
> 
> Dear Martin
> 
> One cubic foot of air, under stoichiometric conditions will support
> combustion that releases 100 BTU
> 
> If you want 1 kw in 1 hour, ie, 1 kwh, you have to liberate 3412 BTU
> 
> Therefore, you need, in theory, 34.12 cubic feet of air.
> 
> Be\cause of poor mixing, etc, you will probably need about 15% top 25%
> excess. Say 20% excess, or say a total of roughly 40 cubic feet of air
> per hour.
> 
> Now, roughly 1/2 should be blown in below the grate, as primary air, to
> make gas, and the other half should be blown in above teh fuel, as
> secondary air, to burn the gas to completion.
> 
> That will be our little secret!! :-)
> 
> Best wishes,
> 
> Kevin
> 
> Boll, Martin Dr. wrote:
> > Dear all,
> >
> >
> >
> > where can I find a rough and ready-number, of the needed air (oxygen)
> amount
> > for e.g. the release of 1kw heat-making wood-gas-amount in a T-LUD-type
> > burner?
> >
> > - I am aware that moisture will make differences.
> >
> > - How many litres air per minute?
> >
> >
> >
> > Regards
> >
> >
> >
> > Martin
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
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