RE: Sweden nuke thread vs. Mercury in coal airborne impacts

[Rosen_Jerry <rosen@radsafe.pitt.edu>]

The last number that I've seen for the US are:  40 tons of mercury per year
to the air and 16 tons in the ash. These are nation wide numbers.

-----Original Message-----
From: ruth_weiner [mailto:ruth_weiner@email.msn.com]
Sent: Tuesday, August 08, 2000 11:29 AM
To: Multiple recipients of list
Subject: Re: Sweden nuke thread vs. Mercury in coal airborne impacts


Can't quite agree with your calculation.  The particulate emission factor
for coal is 16A lb of particulates per ton of coal burned, where A is the
%ash.  So a completely uncontrolled coal plant would emit 160 lb of ash per
ton of coal.  If the Hg is 1 ppm by weight, and the coal is 10% ash, and
assuming all the Hg in ash goes into fly ash -- a bad assumption -- the Hg
emitted would be

6E6 tons coal/yr * 160 lb ash/ton coal * 1E-6 lb Hg/lb ash = 960 lb Hg/year

or about half a ton.  Now, since uranium (that I happen to know about)
partitions 75% in bottom ash, 25% in fly ash, I would assume conservatively
that mercury would at least partition 50/50, so an uncontrolled plant would
emit about 1 quarter ton per year.  In the U. S., 90% particulate control is
common, and many plants achieve 98%, and I find it hard to believe that
Sweden doesn't control ash emission at all.  So if you have 90% control,
that would give an emission of about 48 pounds of mercury a year.  Given the
usual stack height of coal plants, this would  be diluted by a factor of
about 10,000 before it gets to ground level.

These are textbook calculations (my reference is Wark and Warner).

Ruth Weiner
ruth_weiner@msn.com
-----Original Message-----
From: RadiumProj@cs.com <RadiumProj@cs.com>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Date: Tuesday, August 08, 2000 7:31 AM
Subject: Re: Sweden nuke thread vs. Mercury in coal airborne impacts



>Hg releases today into the environment. A single 1000 MWe coal plant
burning
>6 million tons of coal a year will release 6 tons of mercury into the air
at
>1 ppm of mercury in coal.
>




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