[Stoves] re-kindling stoves

[Anand Karve]

Dear Andrew,
the administrators of Heathrow airport just forgot to remember that at their
location it snows in winter!
Yours
A.D.Karve

On Fri, Dec 24, 2010 at 8:29 PM, <ajheggie at gmail.com> wrote:

> On Thursday 23 December 2010 04:38:25 Crispin Pemberton-Pigott wrote:
>
> >
> > the effect. What if the secondary air were preheated to >800C?
> >
> > Exactly - a most relevant question. What I have done is make most of
> > the air pass through the lowest part of the grate where the coal has
> > difficulty falling in (it is angled 15 degrees to assist coverage not
> > but to completely choke the grate). Then I have 2 x 12mm secondary air
> > holes supplying preheated air into the flame as it passes into the
> > combustion chamber lined with 4 ceramic flat plates.
> >
> > The preheating is large, as the grate is really hot, and the preheating
> > effect of the ceramic plates (about 20mm thick) is good.
> >
> > The next issue is the excess air quantity.
>
> Yes I know you preheat secondary air but I was wondering what the effect
> would be on preheating as a test. Generally excess air acts to quench and
> dilute the reaction. I was just wondering if an experimental external
> heating element for the secondary air supply would make any changes to
> the pm. It's really only spark ignition reciprocating engines that need
> air:fuel close to stoichiometric most other combustion processes trade
> off the extra air massflow with the better chance of a fuel, or Product
> of Incomplete Combustion, particle meeting an oxygen molecule.
>
> In fact I imagine the pm rate would drop dramatically if the secondary air
> were enhanced with O2, though of course the increased temperatures may
> have a non intuitive effect.
>
> There will be a compromise to be made because the graphs of lambda, CO,
> PICs and pm will not all map to a single point.
>
> <snipped>
>
> >
> > The flip side of no PM is that they are there, but that they are really
> > really small and can't be seen by the instrument. That is pretty much
> > the history of particle measurement.
>
> Is there evidence that these smaller than pm2.5 particles are as or more
> dangerous? My understanding of another lung disease, from asbestos fibres
> ( long silica crystals) is they are just small enough to incite damaging
> immune response or mutation but too awkward shaped to be engulfed by
> white blood  corpuscles and excreted.
>
>
> >
> > A chemical analogy is the popular belief that there are 'low SO2
> > emission' stoves. What people are measuring is SO2 and when they don't
> > find it, they think it is 'not being produced'. Well, that is sort of
> > true, but if S is in the coal, it is going to be H2S instead of SO2
> > which far worse! SO2 is the desired product.
>
> Yes what goes in must come out either as ash or flue gas
> >
> > We have a long way to go...
>
> Yes but your recent pictures of the modification to an existing, in use,
> stoves show there are big improvements to be made which should be readily
> accepted. Eliminating PMs will reach a limit below which we will struggle
> and we're not near yet
> >
> > It was -31 C this morning and it is very tough on the poor who have to
> > choose between food or heat.
>
> I have never experienced cold like that
>
> > The brutal winters the UK is feeling are
> > also affecting us. Three in a row. Last year 12 C below normal. Eight
> > million animals froze last winter and this year it came early....
>
> We need to put this in perspective, UK dipped down to -18 in one place
> and -8 in the south but the average has been hovering at 0C. The snow
> that arrived early was what the infrastructure couldn't deal with, simply
> because the trade off between expense of readiness verses disruption had
> resulted in most people not being prepared. The ground is still not
> frozen here, if it did there would be far more longer term problems.
>
> What it is showing up is an over dependence on grid electricity for
> maintaining comfort. An interesting boiler related problem, that has
> shown up laxness in installation, is that most urban dwellers have
> heating by gas condensing boilers which require a condensate drain. Where
> this drain has been poorly installed in an exposed position, and the
> acidic condensate frozen, it has caused the boiler to cut out.
>
> Merry Xmas everyone
>
> AJH
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> Stoves mailing list
>
> 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/
> Stoves at lists.bioenergylists.org
>
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
>



-- 
***
Dr. A.D. Karve
President, Appropriate Rural Technology Institute (ARTI)

*Please change my email address in your records to: adkarve at gmail.com *
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20101225/91fbe646/attachment.html>