[Stoves] air for gasification

[Boll, Martin Dr.]

Dear Andrew,

 

 

>When I read your question I though you meant how much air to supply enough
primary air to heat and pyrolyse wood in a tlud to give offgas that then
burned >to give 1kW(t), this will be slightly less because of the retained
carbon.

 

What you write as explanation is exactly the point of my question!

 

I hope, there will be not so much air necessary to make "just smoke".

The intention behind that: 

If I can make with a small amount of air enough smoke to burn that amount of
smoke (possibly easy!!) with natural draft or some other "tricky" things,
the necessity to make all the (amount of) blow or draft for further burning
is not so urgent. 

-Another advantage is then, that this "high"-pressure (compared with a
radial-fan) could easily penetrate a fuel-stack, even if a little bit "too"
dense filled.

(1kW is enough power to manage energy-saving-cooking) 

(-e.g. high compressed air by a hand-pump filled into an inner tyre)

 

If it is then intended to burn the remaining charcoal or not is another
question.

 

I think the possible option to save the remaining charcoal is not bad, even
the opposite could be desirable in some case.

 

For creating the smoke, I think there will be possible narrow
minimum/maximum limits;

-not to starve the fire by minimum and on the other hand/end 

-not to make a complete burn under the un-burnt fuel, from too much air.

That leads me to the question of amount air-flow for a definite cross-square
e.g. 1 square-centimetre, as unit

and following lead to the idea of a non cylindrical fuel-stack (with
different Cross-section during the burning time), to maintain the burn with
less power-output e.g. when the boiling temperature is reached.

 

- I omitted the idea to transport the generated woodgas to separate burners,
as known from normal gas-burners to cook, because I fear tarrying the tubes
by condensing on the tube-way. But I can imagine the directly following
"burner" could be different from the normal T-LUD.

 

Best regards

 

Martin

 

>Message: 4

>Date: Sun, 10 Jun 2007 21:00:46 +0100

>From: AJH <list at sylva.icuklive.co.uk>

>Subject: Re: [Stoves] air for gazification

>To: Discussion of biomass cooking stoves <stoves at listserv.repp.org>

>Message-ID: <r9lo63peofjkp5a16bv6td2tbnm51rkm19 at 4ax.com>

>Content-Type: text/plain; charset=us-ascii

 

>On Fri, 8 Jun 2007 22:08:22 +0200, Boll, Martin Dr. wrote:

> 

> 

>>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 see that Kevin answered the question but sided with the imperialists on
his side of the pond for the units :-(

> 

>- I am aware that moisture will make differences.

>>It shouldn't if we are talking about complete combustion but of course it
does affect the ability to attain good >>combustion.

>> 

>>- How many litres air per minute?

 

>Now did you mean how many litres of air per minute to completely burn wood
to yield 1kW(t)? This is fairly simple >it's the combustion of about 3
grammes of dry wood and as a rule of thumb that requires about

>6 times that mass of air plus a bit of excess air to ensure good
combustion. So the answer would be about 20 >grammes of air or ~25 litres.

> 

>When I read your question I though you meant how much air to supply enough
primary air to heat and pyrolyse wood >in a tlud to give offgas that then
burned to give 1kW(t), this will be slightly less because of the retained
>carbon.

> 

>AJH