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

[Steven Dapra <sjd@swcp.com>]

Aug. 8, 2000	

	In late 1999 I happened upon an website article ("Coal Combustion") by
Alex Gabbard of ORNL.  We exchanged some e-mails, and he told me that the
mean concentration of mercury in coal has been reported as 0.335 ppm.  The
Radium Project posting (below) assumes 1 ppm.

	The Four Corners power plant (in northwestern NM) releases 528 pounds of
mercury annually from 8.5 million tons of coal per year.  It is the tenth
largest power plant in the country.  (These figures are from an online
article in the Albq. (NM) Journal (12-13-99)).  The plant burns
sub-bituminous coal.

	The EPA estimates that 52 tons of mercury per year are emitted from
coal-fired plants in the U. S.  The EPRI estimates 47 tons per year.  EPA
estimates about 158 tons per year of anthropogenic mercury emissions in the
U. S.  EPA also estimates 5000 to 5500 tons per year world-wide of mercury
emissions.  (These figures are from "Mercury Emissions from Coal-Fired
Power Plants," an article that was on the web page of the Center for Energy
and Economic Development.  The article is no longer posted.  I checked
tonight.)  

Steven Dapra
sjd@swcp.com



At 10:27 AM 8/8/00 -0500, you wrote:
>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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