[Stoves] TLUD stoves and tests

[Nikhil Desai]

Crispin:

It is the "continuous burn" combined with higher temperatures that give
coals the capacity to burn cleaner than woods, don't you think?

That is, heating stoves are different from cooking stoves, and carbon
density matters relatively more. Maybe the same reason for raw coal
performing better than coke briquettes; what is the chemical composition
and energy density?

Lab tests are probably more predictable for heating stoves because there is
a basic service standard -- deliver x Heating Degree Days - with some
variation according to local weather conditions and geography.

Still, what matters is not lab tests but contribution to air quality.
Taking out the heating stoves above a certain Heating Degree Days, I wonder
if Ron can provide any citation showing that coal cookstoves contribute
more to deterioration in ambient air quality than biomass cookstoves.
(Partial use for heating is permitted, so long as it's not in extremely
cold areas.)

I don't care what the stove types and ages are. The question is very basic
- in actual practice, has wood contributed more to air quality
deterioration than coal, when it comes to cooking?

There are very few regions I know of where coal is used consistently for
household cooking and competes with wood. The Indian states of Jharkhand
and Bihar may be such - wood in summer, coal in winter, because cooking and
heating are combined.

I am cc'ing Darpan Das here who has written to us before on "smokeless
coal" in India.

I just happen to think coal chemistry is superior to that of wood for
sustained heat.

I also happen to think that this list should cover "Solid Fuel Combustion"
of all types because while coal does have some inherent contaminants to
varying extents - those that end up in ash - it is the overall economics of
all pollutants and their pathways (including ash management) that ought to
be considered because coal does and will continue to compete with wood in
many parts of the world.

Somebody may remember coal versus wood competition in Pennsylvania, Ohio,
and even right here in Virginia. Let me check with the Library of Congress.
(Remember, a hundred odd years ago, a Master's thesis at UIUC did write
that good wood is too valuable to simply burn away for homes!)

I still hope Ron can come up with citations to disprove me.

Nikhil

------------------------------------------------------------------------
Nikhil Desai
(US +1) 202 568 5831
*Skype: nikhildesai888*


On Fri, Jul 27, 2018 at 11:01 AM, Crispin Pemberton-Pigott <
crispinpigott at outlook.com> wrote:

> Dear Ron
>
>
>
> Your cited article does not support your assertion, in fact, contradicts
> it. Nikhil detailed the mis-match so I won't repeat it.
>
>
>
> I have sent you separately a substantial publication showing not only the
> impact of advanced coal burning stoves on a whole city (Ulaanbaatar) but
> also detailing the tests conducted using a modern crossdraft stove and a
> number of fuels.
>
>
>
> Remarkable for those test results is the demonstration that raw coal
> consistently out-performs semi-coked coal briquettes, the supposedly
> "clean" version of coal by a factor of about 5. There are very, very few
> types of stoves that can deliver heat at less than 0.5 mg PM2.5/MJD.
>
>
>
> Coal-burning heating stoves are typically run for long periods of time at
> low power - 10 hours or more, even 24/7. It is at low power than the
> extremely clean combustors turn PM emissions negative. The stoves literally
> clean the air that passes through them while burning raw coal. The
> crossdraft stoves KG4.4 and MN4.2 are optimised to achieve this.
>
>
>
> The cleanest burning wood pellet TLUD I have seen was reported here. It
> was made in Indonesia. I posted photos at the time. The PM2.5 emission mass
> per delivered unit of heat (4 mg) is about half that of an LPG stove tested
> in India (8 mg). The stove is not commercially available as far as I know,
> though at the time the designer had that intention. Technically that level
> of emissions is below the detection limit because the uncertainty bar
> includes zero. I have one of these stoves in my garage.
>
>
>
> As far as I know, the cleanest burning charcoal stove (for CO) is the
> all-ceramic POCA in Maputo loaded with suitably sized lump charcoal. A new
> geopolymer version may out-perform it. We'll see.
>
>
>
> Regards
>
> Crispin
>
>
>
>
>
> -----Original Message-----
> From: Ronal W. Larson <rongretlarson at comcast.net>
> Sent: Friday, July 27, 2018 12:52 AM
> To: Discussion of biomass <stoves at lists.bioenergylists.org>; Crispin
> Pemberton-Pigott <crispinpigott at outlook.com>
> Subject: Re: [Stoves] TLUD stoves and tests
>
>
>
> Crispin et al:
>
>
>
>                 I gave a cite for my assertion.  What is your cite for the
> assertion that coal-burning stoves were ever superior to those tested by
> Jetter et al?
>
>
>
> Ron
>
>
>
>
>
>
>
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