[Stoves] Purple flame

[nari phaltan]

*It could be burning of hydrogen. At that temperatures probably you are
getting some syngas and purple is a combination of red and blue (reddish
flame is characteristic of hydrogen).*
*
*
*Cheers.*
*
*
*Anil*
*
*
On Mon, Sep 24, 2012 at 7:29 PM, Crispin Pemberton-Pigott <
crispinpigott at gmail.com> wrote:

> Dear Dean****
>
> ** **
>
> I think it has something to so with the rate of the pyrolysis of the final
> portion of the fuel. When the zone reaches the bottom, and there is metal
> there, the pyrolysis rate of the final portion of fuel is at a higher rate
> than any equal mass during the rest of the burn.****
>
> ** **
>
> As a result, the composition of the gas changes because the reaction rate
> is different. There is no fuel below the ‘final bit’ to absorb heat (esp
> from drying the fuel below) and also there is no rising moisture from the
> fuel below. Hot water vapour is highly reactive and changes the gas
> composition by changing the reaction speed.****
>
> ** **
>
> I have also notice the change in colour and have a few photos. Do you
> suppose it can be used as an indicator to the cook that the ‘end is near’?
> ****
>
> ** **
>
> Early fire, highest moisture level****
>
> ****
>
> Middle fire, constant moisture level****
>
> ** **
>
> ****
>
> ** **
>
> Late fire, low moisture level, highest pyrolysation rate, higher carbon
> burning portion****
>
> ** **
>
> ****
>
> ** **
>
> Notice that the purple flame is always there, and it is always at the
> point of secondary air entry. This indicates that is may be more related to
> the carbon burn (CO) than any of the speculation above. The overall
> impression is influenced by the bright white emissions from particles. As
> the volatiles are burned away, there are very few particles and the white
> disappears (or yellow if it is not a very hot fire). Thus the ‘change in
> colour’ might be more because the PM disappeared along with the light, than
> the presence of a new colour. The impression on the eyes would be the same
> in both cases.****
>
> ** **
>
> Best regards****
>
> Crispin****
>
> ** **
>
> Hi Stovers!****
>
> ** **
>
> I've been noticing a shift from blue flames above the burning bio-char in
> a TLUD to purple flames nearer the end of the burn when the bottom of the
> pile is glowing bright orange. I suppose that the blue flame is caused by
> burning CO but I wonder why the purple forms after the blue? The blue self
> sustaining flame doesn't heat the water in the pot as well as the purple
> flame phase although the pile of bio-char is fully ignited at that time and
> may account for the more rapid rise in water temperature.****
>
> ** **
>
> Any ideas?****
>
> ** **
>
> Best,****
>
> ** **
>
> Dean****
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
>
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://www.bioenergylists.org/
>
>
>


-- 
Nimbkar Agricultural Research Institute (NARI)
Tambmal, Phaltan-Lonand Road
P.O.Box 44
Phaltan-415523, Maharashtra, India
Ph:91-2166-222396/220945
e-mail:nariphaltan at gmail.com
          anilrajvanshi at gmail.com

http://www.nariphaltan.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20120924/9c8bc70f/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 21904 bytes
Desc: not available
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20120924/9c8bc70f/attachment.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.jpg
Type: image/jpeg
Size: 25954 bytes
Desc: not available
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20120924/9c8bc70f/attachment-0001.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image003.jpg
Type: image/jpeg
Size: 22025 bytes
Desc: not available
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20120924/9c8bc70f/attachment-0002.jpg>