Non-Combustion Emissions Of Mercury In The Great Lakes Airshed
|Description:||Summary: In conjunction with the U.S. EPA, the Chlorine Institute, and the University of Michigan, this project aimed to improve scientific understanding of the quantity and species of mercury vapor emitted to the atmosphere during operation of a chlor-alkali factory.
During the mid-1990s, U.S. factories that rely on mercury in the production of chlorine and sodium hydroxide consumed more than 10 tons of mercury per year per factory. However, these factories have not been able to account for much of the mercury that they consume. Because factory production equipment is hot and mercury is semi-volatile, the possibility of fugitive (non-stack) air emissions has long been recognized and regulated (though without continuous monitoring of non-stack emissions).
EPA’s estimate of fugitive mercury vapor emissions from factories rests on short-duration measurements that were taken in 1972, using methods then available for measuring mercury in air. During the past decade, there have been large advances in equipments and methods for measuring mercury vapor. These advances include continuous values; near real-time values; and long-path optical instruments. In voluntary cooperation with the U.S. chlor-alkali sector, this study brought these advances to bear on vapor emissions from an operating factory.
A non-stack emissions study was conducted at a factory during February 2000.
Oak Ridge National Laboratory reported its results in: G. R. Southworth, S. E. Lindberg, H. Zhang, and F. R. Anscombe. 2004. “Fugitive mercury emissions from a chlor-alkali factory: sources and fluxes to the atmosphere.” Atmospheric Environment, 38, 597-611.
One finding was that fugitive air emissions from the cell-room roof vent are episodic and vary with factory operating conditions (maintenance and minor operational perturbations). Therefore, air emissions are likely to vary widely among factories on a worldwide basis, in accordance with the operating procedures practiced at each.
Properly positioned, real-time mercury vapor analyzers are potentially valuable tools to detect small-scale process vapor leaks.
A preliminary estimate of daily fugitive Hg emissions during this period (~400-600 g per day) indicated that the bulk of the atmospheric loss was emitted from the roof vent of the main production building. This factory was unusual in having a single roof vent.
Sealed former waste ponds were not important sources, emitting mercury at rates comparable to background soils.
One uncertainty was that the study did not witness a full and representative range of maintenance activities and operating conditions typically conducted at a chlor-alkali factory. It is only reasonable to regard the average of 500 g per day witnessed during the study to be a best-case, lower bound estimate of the year around daily average. Only a long-term study that witnesses a full and typical range of maintenance and system malfunctions can provide a surer estimate of emissions.
On the other hand, the studied factory is known to have made equipment improvements that may have reduced air emissions from the rate that was observed during February 2000. U.S. factories have reduced their annual consumption of mercury by about 70 percent since undertaking a voluntary program to reduce replenishment mercury.
Below is a list of organizations with individual contacts that are funding this project.
Organizations Receiving Funding
Below is a list of organizations with individual contacts that are receiving funding for this project.
U.S. Department of Energy - Primary Contact
Oak Ridge National Laboratory
Environmental Sciences Division
Oak Ridge, Tennessee 37831-6138
p: (423) 574-7857
Below is a list of associated organizations that are NOT giving or receiving funding for this project.
Olin Corporation - Partner
190 Carondelet Plaza
Clayton, Missouri 63105-3443
The Chlorine Institute - Partner
1300 Wilson Blvd.
Arlington, Virginia 22209
p: (703) 741-5760
f: (703) 741-6068
Great Lakes Regional Pollution Prevention Roundtable (GLRPPR)
One East Hazelwood Drive Champaign, IL 61820
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