Emission Of Mercury From Chlor-Alkali Plants
|Description:||Summary: The mercury-cell chlor-alkali (MCCA) industry in the U.S. requires about 160 tons of replacement mercury per year. Nobody currently knows the environmental fate of mercury. If most of the missing mercury were lost in the atmosphere, the MCCA would become the leading source of mercury in the country and the Great Lakes Basin.
The objectives of this project were to:
• Ascertain how and where mercury is lost from MCCA plants.
• The forms and fate of mercury from this industrial sector.
The focus was to develop a measurement scheme to quantify both direct and indirect atmospheric losses of mercury during routine chlor-alkali operations, and apply this scheme to an operating plant. Airborne losses were measured from individual cells, as well as the cell building, from locally stored waste deposits and estimated from the overall chlor-alkali plant itself.
Measurements were performed over a period of time sufficient to capture the mercury emission signals from both routine and non-routine operations. The measurement approach involved a combination of methods including multipoint continuous airborne measurements within the cell rooms, spot measurements near individual cells, point source measurements, and direct flux measurements over waste deposits.
A typical MCCA factory contains 24 to more than 100 cells, which together hold 100 to more than 500 tons of mercury. The cells are located either in a closed building or carport type structure which are heavily ventilated to minimize the risk to workers.
The study conducted the following processes:
• Measure Hg concentrations in gas stream being vented outside from the cell room as well as the ventilation rate.
• Real time monitoring of ambient mercury levels in various parts of the cell room to map out of the “hot-spots.” Mercury concentrations were also determined as a function of distance outside the cell room.
• Flux chamber measurements of Hg release from factory floors where a significant amount of mercury is handled.
• Flux chamber measurements of Hg release over water covering mercury in a cell under different temperature conditions and as a function of time.
• Flux chamber measurements over retention ponds, landfills and waste handling facilities.
• Collected samples of water; wastewater and solid wastes at points of flux chamber measurements and analyzed them for total Hg, elemental Hg and reactive Hg.
• Obtained samples of the cell lid and rubber linings for laboratory testing of their capacity to absorb and release mercury.
Samples were collected at the plant during the summer and winter. In addition, sampling was performed intermittently during the year at selected plant interior locations. Because of the potential importance of passive emissions of Hg vapor from contaminated soils and wastes near the plant, direct sampling of fluxes over soil surfaces near the plant buildings and at known sites of waste storage were collected.
The estimates of overall Hg losses based on a mass balance of material flows, sources and sinks, measured Hg levels in and measurements of air flows and exchange rates to calculate Hg fluxes. Similar measurements were made outside of the plant, both immediately adjacent to major points of air emissions, as well as in a selected region downwind.
These data were used with general and specific flow and wind data to calculate local and area-wide fluxes.
There are no reports associated with this project.
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.
Oak Ridge National Laboratory - Partner
Environmental Sciences Division
Oak Ridge, Tennessee 37831-6138
There are no individuals in this organization
associated with this project.
Below is a list of associated organizations that are NOT giving or receiving funding for this project.
Chlorine Institute - Partner
1300 Wilson Blvd.
Arlington, Virginia 22209
p: (703) 741-5760
f: (703) 741-6068
One East Hazelwood Drive; Champaign, IL; 61820; (800) 407-0261; firstname.lastname@example.org