Mercury Emissions from Coal-fired Power Plant :b an Evaluation of Reduction Strategies Using the Analytic Hierarchy Process PDF Download
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Author: Julie C. Metty
Publisher:
ISBN:
Category : Coal-fired power plants
Languages : en
Pages : 388
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Book Description
Author: Julie C. Metty
Publisher:
ISBN:
Category : Coal-fired power plants
Languages : en
Pages : 388
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Book Description
Author: Julie C. Metty
Publisher:
ISBN: 9780493501116
Category : Coal-fired power plants
Languages : en
Pages : 180
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Book Description
Author: J. ADAMS
Publisher:
ISBN:
Category :
Languages : en
Pages : 47
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Book Description
A thorough quantitative understanding of the processes of mercury emissions, deposition, and translocation through the food chain is currently not available. Complex atmospheric chemistry and dispersion models are required to predict concentration and deposition contributions, and aquatic process models are required to predict effects on fish. There are uncertainties in all of these predictions. Therefore, the most reliable method of understanding impacts of coal-fired power plants on Hg deposition is from empirical data. A review of the literature on mercury deposition around sources including coal-fired power plants found studies covering local mercury concentrations in soil, vegetation, and animals (fish and cows (Lopez et al. 2003)). There is strong evidence of enhanced local deposition within 3 km of the chlor-alkali plants, with elevated soil concentrations and estimated deposition rates of 10 times background. For coal-fired power plants, the data show that atmospheric deposition of Hg may be slightly enhanced. On the scale of a few km, modeling suggests that wet deposition may be increased by a factor of two or three over background. The measured data suggest lower increases of 15% or less. The effects of coal-fired plants seem to be less than 10% of total deposition on a national scale, based on emissions and global modeling. The following summarizes our findings from published reports on the impacts of local deposition. In terms of excesses over background the following increments have been observed within a few km of the plant: (1) local soil concentration Hg increments of 30%-60%, (2) sediment increments of 18-30%, (3) wet deposition increments of 11-12%, and (4) fish Hg increments of about 5-6%, based on an empirical finding that fish concentrations are proportional to the square root of deposition. Important uncertainties include possible reductions of RGM to Hg(0) in power plant plumes and the role of water chemistry in the relationship between Hg deposition and fish content. Soil and vegetation sampling programs were performed around two mid-size coal fired power plants. The objectives were to determine if local mercury hot spots exist, to determine if they could be attributed to deposition of coal-fired power plant emissions, and to determine if they correlated with model predictions. These programs found the following: (1) At both sites, there was no correlation between modeled mercury deposition and either soil concentrations or vegetation concentrations. At the Kincaid plant, there was excess soil Hg along heavily traveled roads. The spatial pattern of soil mercury concentrations did not match the pattern of vegetation Hg concentrations at either plant. (2) At both sites, the subsurface (5-10 cm) samples the Hg concentration correlated strongly with the surface samples (0-5 cm). Average subsurface sample concentrations were slightly less than the surface samples, however, the difference was not statistically significant. (3) An unequivocal definition of background Hg was not possible at either site. Using various assumed background soil mercury concentrations, the percentage of mercury deposited within 10 km of the plant ranged between 1.4 and 8.5% of the RGM emissions. Based on computer modeling, Hg deposition was primarily RGM with much lower deposition from elemental mercury. Estimates of the percentage of total Hg deposition ranged between 0.3 and 1.7%. These small percentages of deposition are consistent with the empirical findings of only minor perturbations in environmental levels, as opposed to ''hot spots'', near the plants. The major objective of this study was to determine if there was evidence for ''hot spots'' of mercury deposition around coal-fired power plants. Although the term has been used extensively, it has never been defined. From a public health perspective, such a ''hot spot'' must be large enough to insure that it did not occur by chance, and it must affect water bodies large enough to support a population of subsistence fishers. The results of this study support the hypothesis that neither of these conditions have been met.
Author: John B. Stephenson (au)
Publisher: DIANE Publishing
ISBN: 9781422302422
Category : Science
Languages : en
Pages : 66
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Book Description
In March 2005, the EPA issued a rule that will limit mercury emissions (ME) -- a toxic element that causes neurological problems -- from coal-fired power plants, the nation's largest ind'l. source of ME. Under the rule, ME are to be reduced from a baseline of 48 tons/yr. to 38 tons in 2010 & to 15 tons in 2018. The ME target for 2010 is based on the level of ME achievable with technol. for controlling other pollutants -- which also capture some mercury -- because it believed emerging mercury controls had not been adequately demonstrated. This report: describes the use, availability, & effectiveness of technol. to reduce ME at power plants; & identifies the factors that influence the cost of these technol. & reports on available cost estimates. Tables.
Author: J. ADAMS
Publisher:
ISBN:
Category :
Languages : en
Pages : 97
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Book Description
A thorough quantitative understanding of the processes of mercury emissions, deposition, and translocation through the food chain is currently not available. Complex atmospheric chemistry and dispersion models are required to predict concentration and deposition contributions, and aquatic process models are required to predict effects on fish. However, there are uncertainties in all of these predictions. Therefore, the most reliable method of understanding impacts of coal-fired power plants on Hg deposition is from empirical data. A review of the literature on mercury deposition around sources including coal-fired power plants found studies covering local mercury concentrations in soil, vegetation, and animals (fish and cows). There is strong evidence of enhanced local deposition within 3 km of the chlor-alkali plants, with elevated soil concentrations and estimated deposition rates of 10 times background. For coal-fired power plants, the data show that atmospheric deposition of Hg may be slightly enhanced. On the scale of a few km, modeling suggests that wet deposition may be increased by a factor of two or three over background. The measured data suggest lower increases of 15% or less. The effects of coal-fired plants seem to be less than 10% of total deposition on a national scale, based on emissions and global modeling. The following summarizes our findings from published reports on the impacts of local deposition. In terms of excesses over background the following increments have been observed within a few km of the plant: (1) local soil concentration Hg increments of 30%-60%, (2) sediment increments of 18-30%, (3) wet deposition increments of 11-12%, and (4) fish Hg increments of about 5-6%, based on an empirical finding that fish concentrations are proportional to the square root of deposition. Important uncertainties include possible reductions of RGM to Hg{sub 0} in power plant plumes and the role of water chemistry in the relationship between Hg deposition and fish content. Soil and vegetation sampling programs were performed around two mid-size coal fired power plants. The objectives were to determine if local mercury hot-spots exist, to determine if they could be attributed to deposition of coal-fired power plant emissions, and to determine if they correlated with model predictions. These programs found the following: (1) At both sites, there was no correlation between modeled mercury deposition and either soil concentrations or vegetation concentrations. At the Kincaid plant, there was excess soil Hg along heavily traveled roads. The spatial pattern of soil mercury concentrations did not match the pattern of vegetation Hg concentrations at either plant. (2) At both sites, the subsurface (5-10 cm) samples the Hg concentration correlated strongly with the surface samples (0-5 cm). Average subsurface sample concentrations were slightly less than the surface samples; however, the difference was not statistically significant. (3) An unequivocal definition of background Hg was not possible at either site. Using various assumed background soil mercury concentrations, the percentage of mercury deposited within 10 km of the plant ranged between 1.4 and 8.5% of the RGM emissions. Based on computer modeling, Hg deposition was primarily RGM with much lower deposition from elemental mercury. Estimates of the percentage of total Hg deposition ranged between 0.3 and 1.7%. These small percentages of deposition are consistent with the empirical findings of only minor perturbations in environmental levels, as opposed to ''hot spots'', near the plants. The major objective of this study was to determine if there was evidence for ''hot-spots'' of mercury deposition around coal-fired power plants. Although the term has been used extensively, it has never been defined. From a public health perspective, such a ''hot spot'' must be large enough to insure that it did not occur by chance, and it must affect water bodies large enough to support a population of subsistence fishers. The results of this study support the hypothesis that neither of these conditions has been met.
Author: Jiang Wu
Publisher: Springer
ISBN: 3662463474
Category : Technology & Engineering
Languages : en
Pages : 163
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Book Description
Mercury (Hg) is one of the most toxic heavy metals, harmful to both the environment and human health. Hg is released into the atmosphere from natural and anthropogenic sources and its emission control has caused much concern. This book introduces readers to Hg pollution from natural and anthropogenic sources and systematically describes coal-fired flue gas mercury emission control in industry, especially from coal-fired power stations. Mercury emission control theory and experimental research are demonstrated, including how elemental mercury is oxidized into oxidized mercury and the effect of flue gas contents on the mercury speciation transformation process. Mercury emission control methods, such as existing APCDs (air pollution control devices) at power stations, sorbent injection, additives in coal combustion and photo-catalytic methods are introduced in detail. Lab-scale, pilot-scale and full-scale experimental studies of sorbent injection conducted by the authors are presented systematically, helping researchers and engineers to understand how this approach reduces the mercury emissions in flue gas and to apply the methods in mercury emission control at coal-fired power stations. Readers will arrive at a comprehensive understanding of various mercury emission control methods that are suitable for industrial applications. The book is intended for scientists, researchers, engineers and graduate students in the fields of energy science and technology, environmental science and technology and chemical engineering.
Author:
Publisher: Am Cncl on Science, Health
ISBN:
Category : Coal-fired power plants
Languages : en
Pages : 18
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Book Description
Author:
Publisher: DIANE Publishing
ISBN: 1428900284
Category :
Languages : en
Pages : 346
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 40
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Book Description
The U.S. Environmental Protection Agency (EPA) has announced plans to regulate mercury (Hg) emissions from coal-fired power plants. EPA has not prepared a quantitative assessment of the reduction in risk that could be achieved through reduction in coal plant emissions of Hg. To address this issue, Brookhaven National Laboratory (BNL) with support from the U.S. Department of Energy Office of Fossil Energy (DOE FE) prepared a quantitative assessment of the reduction in human health risk that could be achieved through reduction in coal plant emissions of Hg. The primary pathway for Hg exposure is through consumption of fish. The most susceptible population to Hg exposure is the fetus. Therefore the risk assessment focused on consumption of fish by women of child-bearing age. Dose response factors were generated from studies on loss of cognitive abilities (language skills, motor skills, etc.) by young children whose mothers consumed large amounts of fish with high Hg levels. Population risks were estimated for the general population in three regions of the country, (the Midwest, Northeast, and Southeast) that were identified by EPA as being heavily impacted by coal emissions. Three scenarios for reducing Hg emissions from coal plants were considered: (1) A base case using current conditions; (2) A 50% reduction; and, (3) A 90% reduction. These reductions in emissions were assumed to translate linearly into a reduction in fish Hg levels of 8.6% and 15.5%, respectively. Population risk estimates were also calculated for two subsistence fisher populations. These groups of people consume substantially more fish than the general public and, depending on location, the fish may contain higher Hg levels than average. Risk estimates for these groups were calculated for the three Hg levels used for the general population analyses. Analysis shows that the general population risks for exposure of the fetus to Hg are small. Estimated risks under current conditions (i.e., no specific Hg controls) ranged from 5.7 x 10−6 in the Midwest to 2 x 10−5 in the Southeast. Reducing emissions from coal plants by 90% reduced the estimated range in risk to 5 x 10−6 in the Midwest and 1.5 x 10−5 in Southeast, respectively. The population risk for the subsistence fisher using the Southeast regional fish Hg levels was 3.8 x 10−3, a factor of 200 greater than the general population risk. For the subsistence fishers and the Savannah River Hg levels, the population risk was 4.3 x 10−5, a factor of 2 greater than for the general population. The estimated risk reductions from a 90% reduction in coal plant Hg emissions ranged from 25%-68%, which is greater than the assumed reduction in Hg levels in fish, (15.5%). To place this risk in perspective, there are approximately 4 x 106 births/year in the U.S (National Vital Statistics Report, 2000). Assuming that the Southeast risk level (the highest of the regions) is appropriate for the entire U.S., an estimate of 80 newborn children per year have a 5% chance of realizing any of the 16 adverse effects used to generate the DRF. If Hg emissions from power plants are reduced 90%, the number of children at risk is reduced to 60.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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CONSOL Energy Inc., Research & Development (CONSOL), with support from the U.S. Department of Energy, National Energy Technology Laboratory (DOE) and the Electric Power Research Institute (EPRI), is evaluating the effects of selective catalytic reduction (SCR) on mercury (Hg) capture in coal-fired plants equipped with an electrostatic precipitator (ESP)--wet flue gas desulfurization (FGD) combination or a spray dryer absorber--fabric filter (SDA-FF) combination. In this program CONSOL is determining mercury speciation and removal at 10 coal-fired facilities. The objectives are (1) to evaluate the effect of SCR on mercury capture in the ESP-FGD and SDA-FF combinations at coal-fired power plants, (2) evaluate the effect of catalyst degradation on mercury capture; (3) evaluate the effect of low load operation on mercury capture in an SCR-FGD system, and (4) collect data that could provide the basis for fundamental scientific insights into the nature of mercury chemistry in flue gas, the catalytic effect of SCR systems on mercury speciation and the efficacy of different FGD technologies for mercury capture. This document, the seventh in a series of topical reports, describes the results and analysis of mercury sampling performed on a 1,300 MW unit burning a bituminous coal containing three percent sulfur. The unit was equipped with an ESP and a limestone-based wet FGD to control particulate and SO2 emissions, respectively. At the time of sampling an SCR was not installed on this unit. Four sampling tests were performed in September 2003. Flue gas mercury speciation and concentrations were determined at the ESP outlet (FGD inlet), and at the stack (FGD outlet) using the Ontario Hydro method. Process stream samples for a mercury balance were collected to coincide with the flue gas measurements. The results show that the FGD inlet flue gas oxidized:elemental mercury ratio was roughly 2:1, with 66% oxidized mercury and 34% elemental mercury. Mercury removal, on a coal-to-stack basis, was 53%. The average Hg concentration in the stack flue gas was 4.09 [mu]g/m3. The average stack mercury emission was 3.47 Ib/TBtu. The mercury material balance closures ranged from 87% to 108%, with an average of 97%. A sampling program similar to this one was performed on a similar unit (at the same plant) that was equipped with an SCR for NOx control. Comparison of the results from the two units show that the SCR increases the percentage of mercury that is in the oxidized form, which, in turn, lends to more of the total mercury being removed in the wet scrubber. The principal purpose of this work is to develop a better understanding of the potential mercury removal ''co-benefits'' achieved by NOx, and SO2 control technologies. It is expected that this data will provide the basis for fundamental scientific insights into the nature of mercury chemistry in flue gas, the catalytic effect of SCR systems on mercury speciation and the efficacy of different FGD technologies for mercury capture. Ultimately, this insight could help to design and operate SCR and FGD systems to maximize mercury removal.
