Mercury Control and Measurement was the Hot Topic on October 14
There is going to be a short time period for utilities to react and then comply with the anticipated Utility MACT Rule. Five experts provided insights on the challenges regarding mercury control and measurement to meet the anticipated requirements.
Jean Bustard of ADA-ES addressed two subjects: One was the requirements and the other was the ability to meet the requirements. She pointed out that a number of air and water and even solids regulations will be issued in the next year. McIlvaine contends that the Utility MACT has to be viewed along with the demands of other regulations. For example, if you capture selenium and discharge it into the FGD wastewater you are creating a water pollution problem. In fact the environmental goals are actually
· air purification
· water purification
· prevention of transfer from air to water
· prevention of re-emission from water to air
Jean provided some interesting graphs showing that most coal has raw mercury in the 3-7 lbs/tBtu range. So if the limit is 0.5 lbs/tBtu there will be an efficiency requirement between 80-95 percent for most units. Activated carbon (AC) can be injected ahead of a baghouse but also can be used ahead of a precipitator-scrubber combination. Here the ACI would provide a safety factor if the scrubber cannot by itself meet the limits. The capital cost of the ACI injection system is low, so it is a good investment even if it is seldom used.
Jean believes that there could be as many as 600 coal-fired power plants, 500 industrial boilers and 90 cement plants which presently do not use ACI but will need to start using it in the next four years. In the peak years of 2013 and 2014 as many as 300 systems/yr will be purchased. This could create a shortage of equipment and labor. Jean says that the total procurement cycle for ACI is more than one year.
Ron Landreth of Albemarle provided details on the PPL Corette Station in Montana. A commercial ACI system using cement-friendly sorbent is allowing the plant to sell its flyash while meeting a mercury limit of 0.9 lbs/tBtu. C-PAC consists only of PAC and Br. There are no other additives. Ron stressed the importance of this due to pending guidelines which would prohibit supplemental additives.
Chris Martin and John Pavlish of EERC explained the complex mechanisms by which activated carbon is successfully removing mercury. Some specific nitrogen compounds play a role in converting elemental mercury to the oxidized form. Mercury capture is primarily site limited in the capture of the first 30 percent. Transition effects are important in raising the efficiency to 50 percent. Higher efficiency is “reactant-limited.” As a result of the variables the performance of the ACI/precipitator combination will vary greatly from plant to plant. Therefore pilot or full scale testing is beneficial.
John Foster of SPE-Amerex extrapolated from the experience on incinerators and industrial boilers to predict the equipment needs for Utility MACT. He believes that any of the scrubber types will be able to meet the 3 ppm HCl requirement. Ninety-five percent mercury capture can be achieved but in the case of incinerators there is a high HCl content and therefore little elemental mercury. SPE-Amerex is injecting activated carbon after the counter flow reactor but ahead of the baghouse. The company installed an ACI unit on a utility in Green Bay, Wisconsin last year. The 120 MW unit is achieving 77 percent mercury removal a 6 lbs/MMacf. The injection is upstream of a precipitator.
Bobby Chen of Shaw discussed the potential of EMA which relies on hydrogen bromide instead of calcium bromide. This compound is proving capable of oxidizing more than 90 percent of the elemental mercury and therefore allowing scrubbers to achieve high mercury removal. Annual consumption for a 350 MW unit at full load and injection rates of 3 gph to 10 gph would cost between $200,000 and $400,000. The compound could be used as the only chemical or to reduce the amount of activated carbon required.
The BIOS, ABSTRACTS and PHOTOS can be viewed as follows: BIOS, PHOTOS, ABSTRACTS - October 14, 2010.htm
The individual slides can be viewed in the Mercury Decision Tree as follows:
JEAN BUSTARD – ADA ENVIRONMENTAL SOLUTIONS LLC
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Mercury Continuing Decision Process For: Products
Finding Mercury Control Solutions for Coal-fired Power Plants in the Current Regulatory Maze. Presented by Jean Bustard - ADA Environmental Solutions. Hot Topic Hour October 14, 2010
DR. RONALD LANDRETH – ALBEMARLE/SORBENT TECHNOLOGIES
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Mercury Continuing Decision Process For: Products
How to Maximize Mercury Capture While Preserving Fly Ash Sales. Presented by Dr. Ronald Landreth, Albemarle/Sorbent Technologies. Hot Topic Hour October 14, 2010
JOHN FOSTER – SPE-AMEREX
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Mercury Continuing Decision Process For: Products
Hg and Dioxin/Furan Removal - What has been achieved and what is required. Presented by John Foster, SPE-Amerex. Hot Topic Hour October 14, 2010.
DR. CHRISTOPHER MARTIN AND JOHN PAVLISH - EERC
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Mercury Continuing Decision Process For: Options
Factors that Limit Mercury Capture with Sorbent Injection. Presented by Chris Martin and John Pavlish, EERC. Hot Topic Hour October 14, 2010.
BOBBY CHEN – THE SHAW GROUP
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Mercury Continuing Decision Process For: Products
Enhanced Mercury Oxidization.
Presented by Bobby I.T. Chen, The Shaw Group. Hot Topic Hour October 14, 2010.
http://www.mcilvainecompany.com/Mercury_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Bobby
Chen - The Shaw Group - 10-14-10.pdf