[Stoves] Ph.D. Thesis on TLUD Stoves.

[Paul Olivier]

Tom,

What you say here makes a lot of sense.

Thanks so much.
Paul Olivier


On Fri, Jun 28, 2013 at 9:36 AM, Tom Miles <tmiles at trmiles.com> wrote:

> Paul,****
>
> ** **
>
> The typical impact of higher CO2 is to reduce combustion temperatures and
> make producer gas combustion less stable.  As dilution increases and
> temperatures decrease in upper regions I would expect to see an increase in
> unburned CO. You should be able to measure differences with a small probe
> and thermocouple.  ****
>
> ** **
>
> Tom****
>
> ** **
>
> *From:* Stoves [mailto:stoves-bounces at lists.bioenergylists.org] *On
> Behalf Of *Paul Olivier
> *Sent:* Thursday, June 27, 2013 5:04 PM
>
> *To:* Discussion of biomass cooking stoves
> *Subject:* Re: [Stoves] Ph.D. Thesis on TLUD Stoves.****
>
> ** **
>
> Ron,****
>
> When char is consumed in a fan-powered TLUD, several negative factors come
> into play. At the point where char is consumed, hot zones are created,
> giving rise to temperatures that are truly brutal on all types of metal. As
> a consequence of such high heat, the walls of the reactor can be degraded
> in a matter of months, often times, in just a few weeks.
>
> When char is consumed, the descent of the pyrolitic front is not uniform.
> The syngas generally contains a lot of CO2. An inefficiency in heat
> transfer is created as energy gets released within the reactor at a
> considerable distance from the pot. To compensate for this loss in heat
> transfer, the operator might increase the speed of the fan, and in so
> doing, make matters worse.****
>
> If syngas contains a lot of CO2, I wonder how this affects the combustion
> CO and H2 within the syngas. If CO and H2 are diluted with CO2, do they
> fully combust when exposed to secondary air? Is there a link between the
> presence of CO2 prior to the combustion of the syngas and the presence of
> CO after the combustion of the syngas?****
>
> ** **
>
> When char gets consumed, pockets of ash are created, and they might easily
> contain high levels of cristobalite. This is especially true in the case of
> rice hulls, which contain high levels of amorphous silica. When char gets
> consumed, the quality of the biochar produced is compromised. Ash is not
> biochar, and biochar is not ash.****
>
> Thanks.****
>
> Paul Olivier****
>
> ** **
>
> ** **
>
> On Fri, Jun 28, 2013 at 2:43 AM, <rongretlarson at comcast.net> wrote:****
>
> Julien  and list
>
> 1.  Thanks very much for providing this cite.   I have read most and find
> it to be a well done thesis.   I wish we had more like it.
>
> 2.  The concepts of char and TLUDs are in here thoroughly.  But nothing on
> the idea of a stove designed to make char.  All char is presumed and
> desired to be consumed.
>
> 3.   My conclusion (would like to hear more) is that a good case is made
> (not intentionally) for NOT consuming the produced char in a TLUD  (this
> one fan-powered and widely sold in India as the "Oorja"  (started by BP)).
> Very little gain in overall efficiency as the char is consumed.
>
> 4.  A major advance was his study of the importance of ash in this "char"
> period as a poor radiator - thereby responsible for (undesired) high char
> temperatures.
>
> 5.   Most everything shown as a function of superficial velocity (Vs) -
> with 16-17 cm/sec shown as key dividing point in stove behavior..  Above
> which velocity one swtches from char production to char consumption.   I
> have not seen this before.
>
>     For his highly automated fan system, measuring Vs was apparently not
> so difficult.  Anyone able to give a way to get an easy estimate of Vs,
> when there is only natural draft?
>
> 6.  Quite a bit on the importance of low emissions of CO.
>
> 7.   Good information on both the experimental and computational side of
> top-lit (packed bed) stoves.  Not much here for rocket stoves.
>
> Have I got #3 right?
>
> Ron****
>
>
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> ****
>
>
>
>
> --
> Paul A. Olivier PhD
> 26/5 Phu Dong Thien Vuong
> Dalat
> Vietnam
>
> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
> Mobile: 090-694-1573 (in Vietnam)
> Skype address: Xpolivier
> http://www.esrla.com/ ****
>
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-- 
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam

Louisiana telephone: 1-337-447-4124 (rings Vietnam)
Mobile: 090-694-1573 (in Vietnam)
Skype address: Xpolivier
http://www.esrla.com/
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