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Final Report: Development And Demonstration Of Trace Metals Database
EPA Grant Number: R827649C001Subproject: this is subproject number 001 , established and managed by the Center Director under grant R827649
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for Air Toxic Metals® (CATM®)
Center Director: Groenewold, Gerald
Title: Development And Demonstration Of Trace Metals Database
Investigators: Folkedahl, Bruce C. , Beard, Roy B. , Benson, Steven A. , Galbreath, Kevin C. , Hanson, Paul R. , Hassett, J. , Holmes, Karen , Jensen, John , Laudal, Dennis L. , Maki, Andrew B. , Miller, Stanley J. , Olson, Edwin S. , Pavlish, John H. , Peck, Wes D. , Zygarlicke, Christopher J.
Institution: University of North Dakota
EPA Project Officer: Stelz, Bill
Project Period: October 15, 1999 through October 14, 2002
Project Amount: Refer to main center abstract for funding details.
RFA: Center for Air Toxic Metals (CATM) (1998)
Research Category: Targeted Research
Description:
Objective:The objective of this research project was to address air toxic trace element emissions, which have become a matter of worldwide concern as well as a regulatory issue in the United States. The specific objectives of this research project were to: (1) develop and disseminate critical information on air toxic metal compounds to support development and implementation of pollution prevention and control strategies that will reduce effectively air toxic metal emissions and releases to the environment; and (2) advance the development of a trace metals database.
Summary/Accomplishments (Outputs/Outcomes):In this program area, theoretical or computational models; mechanistic, statistical, and artificial intelligence-based or neural network; and thermochemical equilibrium models were developed, validated, and made available to industry, government, and research organizations.
Database Development
A centralized database of integrated information related to air toxics was created. Over 400,000 analytical measurements from more than 150,000 samples from over 100 large plants or smaller systems were input into the database, including 2,500 coal analyses with complete ash chemistry. A graphical user interface was created to facilitate assessments of health risks, research needs, preventive measures, and emission control strategies. Data were obtained from the U.S. Environmental Protection Agency (EPA) Information Collection Request (ICR) on mercury, the U.S. Geological Survey Coal Quality Database, the Tidd-pressurized fluidized-bed combustion demonstration plant (Department of Energy [DOE] project in the 1990s), Minnesota Power’s Boswell Energy Center, Energy & Environmental Research Center (EERC) test combustors, and many other smaller sources.
Mechanistic Models
An emission calculator was incorporated into the database that predicts trace element emissions on the basis of empirical correlations derived from the emission data from DOE’s Phase I tests on 9 units at 8 sites and 12 additional datasets provided by Electric Power Research Institute. A comparison of the empirically derived emission predictions for As, Cd, Cr, Pb, Ni, Se, and Hg with the results of EERC’s TraceTran equilibrium model indicated close agreement for all elements except Se and Hg. The TraceTran model, which was originally developed to predict trace element transformations in an entrained gasifier, uses coal composition, system design, and operating conditions as input to predict ash and trace element speciation.
A more general model for predicting Hg speciation in coal combustion systems was developed by integrating other available computational modules including: (1) ATRAN, a particle size and composition distribution model; (2) Chemkin, a mercury kinetics model; (3) the general dynamic equation for size distribution of aerosols; and (4) the Fluent computation fluid dynamics model to predict temperature and gas flow patterns. The general model calculates Hg0, Hg2+X(g), and Hg(p) over time to predict transformation rates for oxidized and particulate forms as driven by reactions with acid gases, fly ash, and condensation effects of cooling. Reaction orders and reaction rate constants are derived for Hg adsorption on ash particles. The model has been tested successfully for subbituminous and bituminous coals.
Gas-phase mass transfer to a sorbent was modeled for an experimentally determined sorbent particle-size distribution. The model calculates mercury capture versus time-of-flight at designated sorbent-to-mercury ratios. Model convergence is sensitive to the time increment selected.
Statistical and Neural Network Models
Statistical models were developed linking coal analyses and plant data from the Phase II ICR, with emission factors derived from the Phase III ICR. This analysis of the ICR data predicted that 45tons of Hg were emitted by coal-fired utilities in 1999. The statistically significant variables identified in the model included Cl/ash ratio, cold-side electrostatic precipitators (ESP), hot-side ESP, wet flue gas desulfurization, cyclone firing, and fabric filter/baghouse. Additional statistical analysis was performed incorporating ash chemistry with the ICR data, which indicated that mercury emissions are correlated significantly with calcium and alkali contents in the coal. A neural network model developed in parallel with the statistical analysis identified similar trends. Neural network predictions of mercury speciation and emission were in close agreement with values observed at plants in the ICR at an r2 of 0.975.
Thermochemical Equilibrium Models
Several available thermochemical equilibrium models were evaluated as initial screening tools to guide research efforts, focusing on chromium. Thermochemical equilibrium calculations indicate that carcinogenic hexavalent Cr compounds do not occur in Powder River Basin (PRB) subbituminous coal fly ashes. X-ray absorption fine-structure spectroscopy analysis was performed on five PRB fly ash samples containing 45 to 80 ppm Cr to test the model prediction and answer questions concerning the toxicity of Cr and other transition metal-rich fly ash from PRB coals. Results indicated that between 10 percent and 30 percent of the total Cr content was Cr6+. The experimental results confirm that western United States PRB subbituminous coal fly ashes in general contain more Cr6+ than eastern United States bituminous coal fly ashes. In this instance, the thermochemical equilibrium model does not predict accurately differences between eastern bituminous and western United States subbituminous fly ashes.
Journal Articles on this Report: 4 Displayed | Download in RIS Format
| Other subproject views: | All 33 publications | 14 publications in selected types | All 4 journal articles |
| Other center views: | All 347 publications | 110 publications in selected types | All 52 journal articles |
| Type | Citation | ||
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Laudal DL, Thompson JS, Pavlish JH, Brickett L, Chu P, Srivastava RK, Lee CW, Kilgroe J. Mercury speciation at power plants using SCR and SNCR control technologies. Environmental Manager. 2003;(February):16-22. |
R827649 (2002) R827649 (2003) R827649 (Final) R827649C001 (Final) |
not available |
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Olson ES, Miller SJ, Sharma RK, Dunham GE, Benson SA. Catalytic effects of carbon sorbents for mercury capture. Journal of Hazardous Materials 2000;74(1-2):61-79. |
R827649 (2001) R827649C001 (2001) R827649C001 (Final) |
not available |
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Sondreal EA, Benson SA, Hurley JP, Mann MD, Pavlish JH, Swanson ML, Weber GF, Zygarlicke CJ. Review of advances in combustion technology and biomass cofiring. Fuel Processing Technology. 2001;71(1-3):7-38. |
R827649 (2001) R827649C001 (2001) R827649C001 (Final) |
not available |
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Timpe RC, Mann MD, Pavlish JH. Organic sulfur and hap removal from coal using hydrothermal treatment. Fuel Processing Technology 2001;73(2):127-141. |
R827649 (2000) R827649 (2001) R827649C001 (2001) R827649C001 (Final) |
not available |
air, air quality, analysis, control, emissions, environment, hazardous, measurement, mercury, metals, modeling, pollutants, pollution, sampling, species, toxic, transformations,
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Ecosystem Protection/Environmental Exposure & Risk, Economic, Social, & Behavioral Science Research Program, Air, Scientific Discipline, RFA, Ecosystem/Assessment/Indicators, exploratory research environmental biology, decision-making, air toxics, Economics & Decision Making, Ecological Indicators, Environmental Engineering, Ecological Effects - Human Health, Environmental Chemistry, Chemical Mixtures - Environmental Exposure & Risk, Ecological Effects - Environmental Exposure & Risk, Ecosystem Protection, heavy metals, decision analysis, decision making, trace metals database, models, mercury, chemical databases, environmental decision making
Relevant Websites:
http://www.undeerc.org 
http://www.undeerc.org/catm/index.html
Progress and Final Reports:
2001 Progress Report
2002 Progress Report
Original Abstract
Main Center Abstract and Reports:
R827649 Center for Air Toxic Metals® (CATM®)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R827649C001 Development And Demonstration Of Trace Metals Database
R827649C002 Nickel Speciation Of Residual Oil Ash
R827649C003 Atmospheric Deposition: Air Toxics At Lake Superior
R827649C004 Novel Approaches For Prevention And Control For Trace Metals
R827649C005 Wet Scrubber System
R827649C006 Technology Commercialization And Education
R827649C007 Development Of Speciation And Sampling Tools For Mercury In Flue Gas
R827649C008 Process Impacts On Trace Element Speciation
R827649C009 Mercury Transformations in Coal Combustion Flue Gas
R827649C010 Nickel, Chromium, and Arsenic Speciation of Ambient Particulate Matter in the Vicinity of an Oil-Fired Utility Boiler
R827649C011 Transition Metal Speciation of Fossil Fuel Combustion Flue Gases
R827649C012 Fundamental Study of the Impact of SCR on Mercury Speciation
R827649C013 Development of Mercury Sampling and Analytical Techniques
R827649C014 Longer-Term Testing of Continuous Mercury Monitors
R827649C015 Long-Term Mercury Monitoring at North Dakota Power Plants
R827649C016 Development of a Laser Absorption Continuous Mercury Monitor
R827649C017 Development of Mercury Control Technologies
R827649C018 Developing SCR Technology Options for Mercury Oxidation in Western Fuels
R827649C019 Modeling Mercury Speciation in Coal Combustion Systems
R827649C020 Stability of Mercury in Coal Combustion By-Products and Sorbents
R827649C021 Mercury in Alternative Fuels
R827649C022 Studies of Mercury Metabolism and Selenium Physiology