[Stoves] Off-topic: Re: Tajik coal - fuel quality, stove performance and health effects

[Traveller]

Crispin:

This is not really off-topic. Demonization of "solid fuels" by the WHO/GBD
crowd has been done without an iota of information on coal or biomass
qualities and combustion practices around the world. The claims "Millions
Dead" and promises of "Saving Lives" are hollow.

Since you mention the quality/price variations in the market, it may be
that the mine management has set production and sales targets in kg and
maybe has some captive market for bad coal. (In India, anthracite was used
in railways, who carried loads to dump at the other end of or along the
line so other engines could pick up. It was not at all difficult to unload
some coal from a carriage and put stones in there; just that stones might
have been loaded at the mine to begin with.)

Same thing happens in places where wood is sold for fuel - in shops or home
delivery by women who have collected twigs in woodlands or farms. Thick
logs fetch one price, twigs another, construction/packaging waste according
to type.

Still, there is not a single recent document on the scriptures of "solid
fuels and air pollution" that discusses physical or chemical properties of
fuels and combustion conditions.

Stove design and operations have to match with the fuel specs, otherwise
"more complete combustion" will not be achieved in practice.

(I learnt that lesson as part of a unique coal washing technology employed
at Homer City 3 unit in Pennsylvania. EPA was obsessed with emission rates
one unit at a time, not three "stacked". The same folly it keeps on
repeating now - one combustion device per household, no stacking, so BAMG
can go around cooking up "health benefits". What insanity.)

Nikhil





Message: 6
Date: Fri, 7 Oct 2016 00:03:07 -0400
From: Crispin Pemberton-Pigott <crispinpigott at outlook.com>
To: "Stoves" <stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Deganga case study (Re: Paul, Crispin)
Message-ID: <COL402-EAS1711979D54A5D7186EF2366B1C60 at phx.gbl>
Content-Type: text/plain; charset="utf-8"

Dear Nikhil

?Crispin: Is it any surprise that the mine doesn't wash or grade a high
energy, high-vol coal for small retail sales? What incentive would you
consider for it to do so??

Good question. I asked and found that they used to do both when it was part
of the Soviet Union.

I think they either lost the equipment (breakdown) or it cost something to
run and the customers had no say about it. The main issue is there is so
much stone in the product it greatly interferes with certain combustors
types.

Here is what I pulled out of a TJ Model 1 with a grate modified for coal
burning:

The dark stuff is nearly burned out coke and the white material is fully
burned out stones.

A great deal of what remains inside is stony. I suspect there are places in
the mine with a far high grade and a lot less stone content, but this is
the junk the really poor people burn.

It happens to be high grade ? the part that actually burns and the energy
content is impressive ? double that of the Nalaikh coal in Ulaanbaatar. So
people say it burns for a long time and I agree. This stuff was a complete
failure in a TLUD. I will try again with small chips and run it as a packed
bed gasifier in case that works, but not in the 20-40mm size. No chance.

If they washed it (which involves floating it on a dense liquid) it would
remove the bits that ae just ?stones? but it would change the price because
they would have to keep all the junk they sell now.

The fact is there are different quality products in the market and they
have different prices. Basically you get what you pay for but the imported
Kyrgyz coal is a far better buy in terms of cost per MJ.  It turns out the
Kyrgyz coal has no national market in that country because it is so far
through the mountains they can?t get it out to the north ? so it is sold
across the border to the south.

Sizing is a different matter ? anyone with a shovel and screen can do that
and they are willing to sort it at the retail point.

Here is a typical operation:

They sell an 80mm, 40mm and a 12mm. The duff is sold to the power station
for about 1.3 cents per kg.

The quality of what is in the picture is quite good. The bad stuff is from
Aini Mine. (?Aye-knee? Mine)/



Regards

Crispin
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