[Stoves] A photo of a lab test from Ulaanbaatar

[Dean Still]

Dear Crispin,

I like using the filter method for PM because it's inexpensive ($7,000
including the scale) and the color of the particulate matter is
visible.We're seeing blond PM from wood fueled fan stoves and white PM from
charcoal. Are you seeing this as well?

Also if I don't see PM on the laser then I presume that what's on the
filter might be small particles not seen by the laser? The large filter
collects lots of mass so the scale can be less sensitive and affordable.

It's nice to get a real reading of the total mass but, as we have been
saying, light scattering and real time data is great as well. Generally,
when we cool the flame we seem to get less black PM.

Jim Jetter reports that a TLUD can have fewer fine particles compared to
fan stoves. We're finding the same thing.

Best,

Dean


On Wed, Aug 28, 2013 at 6:37 AM, Crispin Pemberton-Pigott <
crispinpigott at gmail.com> wrote:

> Dear Dean****
>
> ** **
>
> Thanks for the pointer. I will check them out.****
>
> ** **
>
> Regarding the ultrafine particles (UFP): I have been looking for a couple
> of years at equipment that might be able to cover the range from 3
> nanometers (PM0.003) to PM2.5. From what I have learned it requires a train
> of 3 machines in a row to get something meaningfully accurate. It is not
> that there are machines which can do a section of that spectrum each, it is
> that a machine can tell us what the mass is, but not the size. Some can
> determine the size but not the mass or density. This is not a general
> agreement on whether the number of particles is more important than the
> total mass, though it seems to lean towards the number at the moment
> (because the mass is so small) but the arguments are shaky. Mass matters,
> it is just very small.****
>
> ** **
>
> A train of three machines that can report the mass and number costs about
> $80,000. That is too steep for most people. A whole SeTAR lab costs about
> $65,000 with a combustion analyser and optical particle counter. With a
> much better NDIR machine and a TEOM it costs about $105,000 with the
> different being almost entirely the two machines. A test-day would cost
> about $600/$1000 to perform.****
>
> ** **
>
> The issue of money, if overcome, is not the whole solution. Collecting and
> quantifying UFP on a mass basis is seriously difficult. In many countries
> there are only a few people who can consistently weigh a filter to within
> to 1 microgram or less. If we go for number of particles only, there are
> serious dilution issues because of the huge range to be covered – the SeTAR
> Lab setup can deal with a range of perhaps 2 million to 1. But it is going
> to struggle with getting 10 or 15 g/cubic metre smoke predictably down to
> <100,000 ultra-fine particles per cu cm from tens of billions.****
>
> ** **
>
> Stove emissions are about the hardest thing to quantify because it boils
> down to being able to measure anything anyone could burn. At least in
> industry people have a clue what they are burning from day to day.****
>
> ** **
>
> Regards****
>
> Crispin****
>
> ** **
>
> Dear Crispin,****
>
> ** **
>
> Sounds great! I agree that light scattering is better for some uses
> although I have been rattled by certain stoves (mostly fan stoves) that had
> a lot of smaller PM that was missed by the laser.****
>
> ** **
>
> But for improving a stove I believe that light scattering is OK just not
> for comparing stoves with different types of fires.****
>
> ** **
>
> The big filters can be purchased from HI-Q Environmental Products Co. at
> www.HI-Q.net****
>
> ** **
>
> We are doing a lot of stove improving and, like you, I believe that the
> major reason for having emissions equipment is to get to better
> performance. Testing should not be a good in and of itself. There are too
> many serious problems needing to be addressed, as you say.****
>
> ** **
>
> All Best,****
>
> ** **
>
> Dean****
>
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> A
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