[Stoves] ***SPAM*** Re: Stoves Digest, Vol 131, Issue 14

[Norbert Senf]

Hi Andrew:
There's a fairly clear distinction between the PM resulting from flaming
and from smoldering. Ie. soot vs tar, or elemental carbon and organic
carbon (EC and OC).
I found a study from Switzerland comparing the toxicity of the two, and it
appears that OC is about 10X as toxic as EC.
In a pellet stove or masonry heater, for example you see around 1 g/kg of
EC, whereas in an "outdoor boiler" like farmers around here use, you can
see as high as 100 g/kg of OC.
This implies that burning the same piece of wood could give you 1000 X the
toxicity in one device compared to the other.
Outdoor boilers have water cooled fireboxes, and a combustion air fan which
allows you to burn green wood.
They tend to be oversized, and as a result operate in smolder mode a large
part of the time. If you had to design a device for making creosote, they
would fit the bill very well ;-)

Norbert

On Mon, Jul 26, 2021 at 7:19 AM Norbert Senf <norbert.senf at gmail.com> wrote:

>
>
>
>
>> Message: 1
>> Date: Sun, 25 Jul 2021 17:49:05 +0100
>> From: ajheggie at gmail.com
>> (snip)
>
>
> Hi Andrew:
> Some additional observations based on your last comments:
>
> PM 2.5 is a subset of PM 10. Woodsmoke is actually 99% PM 1.0 (or smaller).
> Coming onto the scene and not much studied yet are nanoparticles. These
> don't
> have any weight to speak of.
>
> Conversion factors for PM were hard to find. I have a rough calculator now
> in Excel that
> has checked out reasonably well.
> At 75% efficiency (HHV) and normalized to 13% O2,
> 1 g/kg =  85.5 mg/m3 at standard temperature and pressure
> =  0.194 lb/MMBtu
> = 83.4 mg/MJ
>
> From masonry heater observations, flame quenching (lots of air, fire is
> starting, flames hit cold surface)
> gives us soot (elemental carbon) and the smoke is light grey to black
>
> Blue smoke is tar. Like with cigarette smoke (smoldering combustion), the
> particles are small enough to refract light, which causes the blue color.
>
> Norbert
>
> --
> Norbert Senf
> Masonry Stove Builders
> 25 Brouse Road, RR 5
> Shawville Québec J0X 2Y0
> 819.647.5092
> www.heatkit.com
>


-- 
Norbert Senf
Masonry Stove Builders
25 Brouse Road, RR 5
Shawville Québec J0X 2Y0
819.647.5092
www.heatkit.com
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