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, <[email protected]> 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/ > [email protected] > > 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: [email protected] *
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