Thermodynamic And Kinetic Study Of Carbon Dioxide And Mercury Removal From Flue Gas In Coal Combustion Power Plants

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Thermodynamic and Kinetic Study of Carbon Dioxide and Mercury Removal from Flue Gas in Coal Combustion Power Plants

Author : Kun Liu
Publisher :
ISBN 13 :
Total Pages : 227 pages
Book Rating : 4.:/5 (894 download)

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Book Synopsis Thermodynamic and Kinetic Study of Carbon Dioxide and Mercury Removal from Flue Gas in Coal Combustion Power Plants by : Kun Liu

Download or read book Thermodynamic and Kinetic Study of Carbon Dioxide and Mercury Removal from Flue Gas in Coal Combustion Power Plants written by Kun Liu and published by . This book was released on 2012 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon dioxide and mercury from anthropogenic emissions pose a significant threat to our environment and human health. Removal from their major source -- coal-fired power plants -- is one of the most effective approaches to control their emissions. Thermodynamics and kinetics are critical to the studies of the removal technologies as they provide fundamental knowledge of the capture process. In this work, the thermodynamics and kinetics of CO2 and Hg capture through absorption using aqueous amines solutions and adsorption using supported ionic liquid sorbents were investigated. A vapor-liquid equilibrium (VLE) data reduction method that simplifies experimental measurements while maintaining accuracy was applied for the first time to the thermodynamic study of CO2 absorption in aqueous amine systems. The method eliminates the measurements of speciation in liquid phase and vapor phase by applying a layer of mass balance iteration in the correlation. Incorporating the electrolyte non-random two liquid (eNRTL) model and the Soave-Redlich-Kwong (SRK) model, the data reduction method was used to correlate VLE and heat of absorption data collected in a modified batch calorimeter for ethanolamine (MEA) - H2O - CO2 system and piperazine (PZ) - H2O - CO2 systems. The optimized model with the best-fit eNRTL model parameters was used to predict vapor pressures under the conditions reported in the literature; the predicted values were consistent with the independent literature results, indicating successful application of the Barker data reduction method and the mathematical model in the thermodynamic study of CO2-aqueous amine systems. With the current technologies, capture of CO2 and Hg from coal combustion flue gas requires additional air pollution control devices that can only do a single task . To reduce the cost, a new approach to capture both CO2 and Hg from coal combustion flue gas in an integrated adsorbent system was discovered. In this approach, a task-specific amino acid ionic liquid is supported on silica gel particles with high surface area and pore volume. The CO2 capacity for was found to be 0.4 mol of CO2/ mol of ionic liquid. The ionic liquid loading was optimal for CO2 capture at 40 wt%. Mass transfer in fixed-bed trials was slow at high ionic liquid loadings due to the decreasing in contact surface area. Hg capture performance was assessed for the same material under a nitrogen environment. These sorbent systems had a total Hg uptake of more than 14 mg/g. Slipstream testing of the sorbents, along with other novel Hg sorbents developed previously, using coal combustion flue gas showed promising and competitive results in Hg removal rate and Hg capacity. When both CO2 and Hg are present in the gas phase, it is expected that Hg accumulates and fixes in the sorbent via strong chemical bonding over an extended time, while CO2 can reversibly be adsorbed and desorbed on the sorbent. This hypothesis was validated by the experimental evidence that the present of CO2 has limited effect on the capture of elemental Hg vapor and the theoretical evidence that oxidized Hg has a stronger bonding with the ionic liquid than CO2.

Coal Fired Flue Gas Mercury Emission Controls

Author : Jiang Wu
Publisher : Springer
ISBN 13 : 3662463474
Total Pages : 163 pages
Book Rating : 4.6/5 (624 download)

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Book Synopsis Coal Fired Flue Gas Mercury Emission Controls by : Jiang Wu

Download or read book Coal Fired Flue Gas Mercury Emission Controls written by Jiang Wu and published by Springer. This book was released on 2015-03-17 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Fundamental Understanding of Mercury Removal from Coal Combustion

Author : Erdem Sasmaz
Publisher : Stanford University
ISBN 13 :
Total Pages : 195 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis Fundamental Understanding of Mercury Removal from Coal Combustion by : Erdem Sasmaz

Download or read book Fundamental Understanding of Mercury Removal from Coal Combustion written by Erdem Sasmaz and published by Stanford University. This book was released on 2011 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal-fired power plants are a major anthropogenic source of worldwide mercury (Hg) emissions. Since mercury is considered to be one of the most toxic metals found in the environment, Hg emissions from coal-fired power plants is of major environmental concern. Mercury in coal is vaporized into its gaseous elemental form throughout the coal combustion process. Elemental Hg can be oxidized in subsequent reactions with other gaseous components (homogeneous) and solid materials (heterogeneous) in coal-fired flue gases. While oxidized Hg in coal-fired flue gases is readily controlled by its adsorption onto fly ash and/or its dissolution into existing solution-based sulfur dioxide (SO2) scrubbers, elemental Hg is not controlled. The extent of elemental Hg formed during coal combustion is difficult to predict since it is dependent on the type of coal burned, combustion conditions, and existing control technologies installed. Therefore, it is important to understand heterogeneous Hg reaction mechanisms to predict the speciation of Hg emissions from coal-fired power plants to design and effectively determine the best applicable control technologies. In this work, theoretical and experimental investigations have been performed to investigate the adsorption and in some cases the oxidation, of Hg on solid surfaces, e.g., calcium oxide (CaO), noble metals and activated carbon (AC). The objective of this research is to identify potential materials that can be used as multi-pollutant sorbents in power plants by carrying out both high-level density functional theory (DFT) electronic structure calculations and experiments to understand heterogeneous chemical pathways of Hg. This research uses a fundamental science-based approach to understand the environmental problems caused by coal-fired energy production and provides solutions to the power generation industry for emissions reductions. Understanding the mechanism associated with Hg and SO2 adsorption on CaO will help to optimize the conditions or material to limit Hg emissions from the flue gas desulfurization process. Plane-wave DFT calculations were used to investigate the binding mechanism of Hg species and SO2 on the CaO(100) surface. The binding strengths on the high-symmetry CaO adsorption sites have been investigated for elemental Hg, SO2, mercury chlorides (HgCl and HgCl2) and mercuric oxide (HgO). It has been discovered that HgCl, HgCl2, and SO2 chemisorb on the CaO(100) surface at 0.125 ML coverage. Binding energies of elemental Hg are minimal indicating a physisorption mechanism. Noble metals such as palladium (Pd), gold (Au), silver (Ag), and copper (Cu) have been proposed to capture elemental Hg. Plane-wave DFT calculations have been carried out to investigate the mercury interactions with Pd binary alloys and overlays in addition to pure Pd, Au, Ag, and Cu surfaces. It has been determined that Pd has the highest mercury binding energy in comparison to other noble metals. In addition, Pd is found to be the primary surface atom responsible for increasing the adsorption of Hg with the surface in both Pd binary alloys and overlays. Deposition of Pd overlays on Au and Ag has been found to enhance the reactivity of the surface by shifting the d-states of surface atoms up in energy. The possible binding mechanisms of elemental Hg onto virgin, brominated and sulfonated AC fiber and brominated powder AC sorbents have been investigated through packed-bed experiments in a stream of air and simulated flue gas conditions, including SO2, hydrogen chloride (HCl), nitrogen oxide (NO) nitrogen dioxide (NO2). A combination of spectroscopy and plane-wave DFT calculations was used to characterize the sorption process. X-ray photoelectron spectroscopy (XPS) and x-ray absorption fine structure (XAFS) spectroscopy were used to analyze the surface and bulk chemical compositions of brominated AC sorbents reacted with Hg0. Through XPS surface characterization studies it was found that Hg adsorption is primarily associated with halogens on the surface. Elemental Hg is oxidized on AC surfaces and the oxidation state of adsorbed Hg is found to be Hg2+. Though plane-wave DFT and density of states (DOS) calculations indicate that Hg is more stable when it is bound to the edge carbon atom interacting with a single bromine bound atop of Hg, a model that includes an interaction between the Hg and an additional Br atom matches best with experimental data obtained from extended x-ray absorption fine structure (EXAFS) spectroscopy. The flue gas species such as HCl and bromine (Br2) enhance the Hg adsorption, while SO2 is found to decrease the Hg adsorption significantly by poisoning the active sites on the AC surface. The AC sorbents represent the most market-ready technology for Hg capture and therefore have been investigated by both theory and experiment in this work. Future work will include similar characterization and bench-scale experiments to test the metal-based materials for the sorbent and oxidation performance.

Carbon Dioxide Removal from Coal-Fired Power Plants

Author : C. Hendriks
Publisher : Springer Science & Business Media
ISBN 13 : 9401103011
Total Pages : 232 pages
Book Rating : 4.4/5 (11 download)

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Book Synopsis Carbon Dioxide Removal from Coal-Fired Power Plants by : C. Hendriks

Download or read book Carbon Dioxide Removal from Coal-Fired Power Plants written by C. Hendriks and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1. 1. Greenhouse gas emissions and climate change . . . . . . . . . . . . . . 3 1. 1. 1. Emissions and concentrations of greenhouse gases 3 1. 1. 2. Impact of increasing greenhouse gases concentration 4 1. 2. Options to reduce carbon dioxide emissions 5 1. 2. 1. Carbon dioxide removal 8 1. 3. Scope of the thesis 10 1. 4. Outline of the thesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. 4. 1. General evaluation method. . . . . . . . . . . . . . . . . . . . . . . 12 1. 4. 2. Some notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 II. Simulation and optimization of carbon dioxide recovery from the flue gases of a coal-fired power plant using amines 14 Abstract 19 2. 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2. 2. The chemical absorption process. . . . . . . . . . . . . . . . . . . . . . . . 22 2. 2. 1. General process description. . . . . . . . . . . . . . . . . . . . . . . 22 2. 2. 2. Types of absorbent 23 2. 2. 3. Effects of flue gas contaminants 24 2. 3. Simulation of the scrubber in ASPEN PLUS . . . . . . . . . . . . . . . . . 25 2. 3. 1. ASPEN PLUS for flow sheet simulation 26 2. 3. 2. Simulation of the performance for the base-case design . . 26 the scrubber . . . . . . . . . . . . . . . . . . . . . . 29 2. 3. 3. Optimization of 2. 3. 4. Design and results 32 2. 3. 5. Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2. 4. Integration of the scrubber in the power plant 35 2. 4. 1. Power loss caused by steam extraction 36 2. 4. 2. Power saved by avoiding preheating boiler feed water . . . 38 2. 4. 3. Power consumption by the carbon dioxide scrubber . . . . . 38 2. 4. 4. Power consumption for carbon dioxide compression . . . . . 38 2. 4. 5. Calculation of plant efficiency losses " . . . . . . . . . . . . . . 39 2. 5.

Fundamental Understanding of Mercury Removal from Coal Combustion

Author : Erdem Sasmaz
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (746 download)

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Book Synopsis Fundamental Understanding of Mercury Removal from Coal Combustion by : Erdem Sasmaz

Download or read book Fundamental Understanding of Mercury Removal from Coal Combustion written by Erdem Sasmaz and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal-fired power plants are a major anthropogenic source of worldwide mercury (Hg) emissions. Since mercury is considered to be one of the most toxic metals found in the environment, Hg emissions from coal-fired power plants is of major environmental concern. Mercury in coal is vaporized into its gaseous elemental form throughout the coal combustion process. Elemental Hg can be oxidized in subsequent reactions with other gaseous components (homogeneous) and solid materials (heterogeneous) in coal-fired flue gases. While oxidized Hg in coal-fired flue gases is readily controlled by its adsorption onto fly ash and/or its dissolution into existing solution-based sulfur dioxide (SO2) scrubbers, elemental Hg is not controlled. The extent of elemental Hg formed during coal combustion is difficult to predict since it is dependent on the type of coal burned, combustion conditions, and existing control technologies installed. Therefore, it is important to understand heterogeneous Hg reaction mechanisms to predict the speciation of Hg emissions from coal-fired power plants to design and effectively determine the best applicable control technologies. In this work, theoretical and experimental investigations have been performed to investigate the adsorption and in some cases the oxidation, of Hg on solid surfaces, e.g., calcium oxide (CaO), noble metals and activated carbon (AC). The objective of this research is to identify potential materials that can be used as multi-pollutant sorbents in power plants by carrying out both high-level density functional theory (DFT) electronic structure calculations and experiments to understand heterogeneous chemical pathways of Hg. This research uses a fundamental science-based approach to understand the environmental problems caused by coal-fired energy production and provides solutions to the power generation industry for emissions reductions. Understanding the mechanism associated with Hg and SO2 adsorption on CaO will help to optimize the conditions or material to limit Hg emissions from the flue gas desulfurization process. Plane-wave DFT calculations were used to investigate the binding mechanism of Hg species and SO2 on the CaO(100) surface. The binding strengths on the high-symmetry CaO adsorption sites have been investigated for elemental Hg, SO2, mercury chlorides (HgCl and HgCl2) and mercuric oxide (HgO). It has been discovered that HgCl, HgCl2, and SO2 chemisorb on the CaO(100) surface at 0.125 ML coverage. Binding energies of elemental Hg are minimal indicating a physisorption mechanism. Noble metals such as palladium (Pd), gold (Au), silver (Ag), and copper (Cu) have been proposed to capture elemental Hg. Plane-wave DFT calculations have been carried out to investigate the mercury interactions with Pd binary alloys and overlays in addition to pure Pd, Au, Ag, and Cu surfaces. It has been determined that Pd has the highest mercury binding energy in comparison to other noble metals. In addition, Pd is found to be the primary surface atom responsible for increasing the adsorption of Hg with the surface in both Pd binary alloys and overlays. Deposition of Pd overlays on Au and Ag has been found to enhance the reactivity of the surface by shifting the d-states of surface atoms up in energy. The possible binding mechanisms of elemental Hg onto virgin, brominated and sulfonated AC fiber and brominated powder AC sorbents have been investigated through packed-bed experiments in a stream of air and simulated flue gas conditions, including SO2, hydrogen chloride (HCl), nitrogen oxide (NO) nitrogen dioxide (NO2). A combination of spectroscopy and plane-wave DFT calculations was used to characterize the sorption process. X-ray photoelectron spectroscopy (XPS) and x-ray absorption fine structure (XAFS) spectroscopy were used to analyze the surface and bulk chemical compositions of brominated AC sorbents reacted with Hg0. Through XPS surface characterization studies it was found that Hg adsorption is primarily associated with halogens on the surface. Elemental Hg is oxidized on AC surfaces and the oxidation state of adsorbed Hg is found to be Hg2+. Though plane-wave DFT and density of states (DOS) calculations indicate that Hg is more stable when it is bound to the edge carbon atom interacting with a single bromine bound atop of Hg, a model that includes an interaction between the Hg and an additional Br atom matches best with experimental data obtained from extended x-ray absorption fine structure (EXAFS) spectroscopy. The flue gas species such as HCl and bromine (Br2) enhance the Hg adsorption, while SO2 is found to decrease the Hg adsorption significantly by poisoning the active sites on the AC surface. The AC sorbents represent the most market-ready technology for Hg capture and therefore have been investigated by both theory and experiment in this work. Future work will include similar characterization and bench-scale experiments to test the metal-based materials for the sorbent and oxidation performance.

Fundamentals of Mercury Transformations in Coal Combustion Flue Gas

Author : Balaji Krishnakumar
Publisher :
ISBN 13 :
Total Pages : 798 pages
Book Rating : 4.:/5 (262 download)

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Book Synopsis Fundamentals of Mercury Transformations in Coal Combustion Flue Gas by : Balaji Krishnakumar

Download or read book Fundamentals of Mercury Transformations in Coal Combustion Flue Gas written by Balaji Krishnakumar and published by . This book was released on 2008 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Mercury Reaction Chemistry in Combustion Flue Gases from Experiments and Theory

Author : Bihter Padak
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (743 download)

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Book Synopsis Mercury Reaction Chemistry in Combustion Flue Gases from Experiments and Theory by : Bihter Padak

Download or read book Mercury Reaction Chemistry in Combustion Flue Gases from Experiments and Theory written by Bihter Padak and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Emissions from coal combustion processes constitute a significant amount of the elemental mercury released into the atmosphere today. Coal-fired power plants in the United States, with the capacity of just over 300GW, are the greatest anthropogenic source of mercury emissions. Mercury exists in coal combustion flue gas in a variety of forms depending on the coal type and combustion conditions; i.e., elemental, oxidized and particulate. Particulate mercury in the flue gas can be removed using air pollution control devices such as electrostatic precipitators and fabric filters. Oxidized mercury is easily captured by wet flue gas desulfurization scrubbers, while gaseous elemental mercury passes through the scrubbers readily. Activated carbon, when injected into the gas stream of coal-fired boilers, is effective in capturing both elemental and oxidized mercury through adsorption processes. However, the mechanism by which mercury adsorbs on activated carbon is not exactly known and its understanding is crucial to the design and fabrication of effective capture technologies for mercury. The objective of the current study is to apply theoretical-based cluster modeling to examine the possible binding mechanism of mercury on activated carbon. The effects of activated carbon's different surface functional groups and halogens on elemental mercury adsorption have been examined. Also, a thermodynamic approach is followed to examine the binding mechanism of mercury and its oxidized species such as HgCl and HgCl2 on a simulated carbon surface with and without Cl. Energies of different possible surface complexes and possible products are compared and dominant pathways are determined relatively. Since different methods are employed to capture varying forms of mercury, understanding mercury speciation during combustion and how the transformations occur between different forms is essential to developing an effective control mechanism for removing mercury from flue gas. In this study, homogeneous oxidation of mercury via chlorine is examined experimentally in a simulated flue gas environment. Mercury and chlorine are introduced into a laminar premixed methane-air flame. Cooled flue gas is sampled and sent to a custom-built electron ionization quadrupole mass spectrometer specially designed for mercury measurement on the order of parts per billion (ppb) in flue gas. The use of a mass spectrometer allows for distinguishing between the different forms of oxidized mercury (Hg+, Hg+2). By directly measuring mercury species accurately, one can determine the actual extent of mercury oxidation in the flue gas, which will aid in further developing mercury control technologies.

Mercury Removal from Simulated Coal-fired Power Plant Flue Gas Using Uv Irradiation and Silica-titania Composites

Author : Alexander F. Gruss
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (779 download)

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Book Synopsis Mercury Removal from Simulated Coal-fired Power Plant Flue Gas Using Uv Irradiation and Silica-titania Composites by : Alexander F. Gruss

Download or read book Mercury Removal from Simulated Coal-fired Power Plant Flue Gas Using Uv Irradiation and Silica-titania Composites written by Alexander F. Gruss and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Mercury is listed as a hazardous air pollutant (HAP) because of its adverse health effects on humans. Without technologies that effectively remove mercury that is contained in the flue gas of coal combustion power plants, the long-term effects on the nation's health could be catastrophic. This research builds on previous work to examine mercury removal at typical flue gas temperatures (up to 375°F), multiple flue gas components (SO2, NO2, HCl), and short contact times (0.3 - 2 s) by studying photocatalytic oxidation and capture of mercury by a silica-titania composite technology coated onto ceramic packing material. Experiments conducted under flue gas conditions showed little change in Hg removal performance when the temperature was increased from 275°F to 375°F. Both oxidation and adsorption seemed to be inhibited by moisture at 375°F, except when chlorine was present. Moisture had a significant detrimental effect on oxidation levels of mercury by UV alone, particularly at a wavelength of 254 nm.

Mercury Speciation in Coal-Fired Power Plant Flue Gas-Experimental Studies and Model Development

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (727 download)

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Book Synopsis Mercury Speciation in Coal-Fired Power Plant Flue Gas-Experimental Studies and Model Development by :

Download or read book Mercury Speciation in Coal-Fired Power Plant Flue Gas-Experimental Studies and Model Development written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall goal of the project was to obtain a fundamental understanding of the catalytic reactions that are promoted by solid surfaces present in coal combustion systems and develop a mathematical model that described key phenomena responsible for the fate of mercury in coal-combustion systems. This objective was achieved by carefully combining laboratory studies under realistic process conditions using simulated flue gas with mathematical modeling efforts. Laboratory-scale studies were performed to understand the fundamental aspects of chemical reactions between flue gas constituents and solid surfaces present in the fly ash and their impact on mercury speciation. Process models were developed to account for heterogeneous reactions because of the presence of fly ash as well as the deliberate addition of particles to promote Hg oxidation and adsorption. Quantum modeling was used to obtain estimates of the kinetics of heterogeneous reactions. Based on the initial findings of this study, additional work was performed to ascertain the potential of using inexpensive inorganic sorbents to control mercury emissions from coal-fired power plants without adverse impact on the salability fly ash, which is one of the major drawbacks of current control technologies based on activated carbon.

Field Test Program for Long-Term Operation of a COHPAC System for Removing Mercury from Coal-Fired Flue Gas

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (727 download)

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Book Synopsis Field Test Program for Long-Term Operation of a COHPAC System for Removing Mercury from Coal-Fired Flue Gas by :

Download or read book Field Test Program for Long-Term Operation of a COHPAC System for Removing Mercury from Coal-Fired Flue Gas written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With the Nation's coal-burning utilities facing the possibility of tighter controls on mercury pollutants, the U.S. Department of Energy is funding projects that could offer power plant operators better ways to reduce these emissions at much lower costs. Sorbent injection technology represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. It involves injecting a solid material such as powdered activated carbon into the flue gas. The gas-phase mercury in the flue gas contacts the sorbent and attaches to its surface. The sorbent with the mercury attached is then collected by the existing particle control device along with the other solid material, primarily fly ash. During 2001, ADA Environmental Solutions (ADA-ES) conducted a full-scale demonstration of sorbent-based mercury control technology at the Alabama Power E.C. Gaston Station (Wilsonville, Alabama). This unit burns a low-sulfur bituminous coal and uses a hot-side electrostatic precipitator (ESP) in combination with a Compact Hybrid Particulate Collector (COHPAC{reg_sign}) baghouse to collect fly ash. The majority of the fly ash is collected in the ESP with the residual being collected in the COHPAC{reg_sign} baghouse. Activated carbon was injected between the ESP and COHPAC{reg_sign} units to collect the mercury. Short-term mercury removal levels in excess of 90% were achieved using the COHPAC{reg_sign} unit. The test also showed that activated carbon was effective in removing both forms of mercury-elemental and oxidized. However, a great deal of additional testing is required to further characterize the capabilities and limitations of this technology relative to use with baghouse systems such as COHPAC{reg_sign}. It is important to determine performance over an extended period of time to fully assess all operational parameters. The project described in this report focuses on fully demonstrating sorbent injection technology at a coal-fired power generating plant that is equipped with a COHPAC{reg_sign} system. The overall objective is to evaluate the long-term effects of sorbent injection on mercury capture and COHPAC{reg_sign} performance. The work is being done on one-half of the gas stream at Alabama Power Company's Plant Gaston Unit 3 (nominally 135 MW). Data from the testing will be used to determine: (1) If sorbent injection into a high air-to-cloth ratio baghouse is a viable, long-term approach for mercury control; and (2) Design criteria and costs for new baghouse/sorbent injection systems that will use a similar, polishing baghouse (TOXECON{trademark}) approach.

Development of Mercury Control Technology for Coal-fired Systems

Author :
Publisher :
ISBN 13 :
Total Pages : 12 pages
Book Rating : 4.:/5 (683 download)

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Book Synopsis Development of Mercury Control Technology for Coal-fired Systems by :

Download or read book Development of Mercury Control Technology for Coal-fired Systems written by and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emission of hazardous air pollutants (air toxics) from various industrial processes has emerged as a major environmental issue that was singled out for particular attention in the Clean Air Act Amendments of 1990. In particular, mercury emissions are the subject of several current EPA studies because of concerns over possible serious effects on human health. Some of those emissions originate in the combustion of coal, which contains trace amounts of mercury, and are likely to be the subject of control requirements in the relatively near future. Data collected by the Department of Energy (DOE) and the Electric Power Research Institute (EPRI) at operating electric-power plants have shown that conventional flue-gas cleanup (FGC) technologies are not very effective in controlling emissions of mercury in general, and are particularly poor at controlling emissions of elemental mercury. This paper gives an overview of research being conducted at Argonne National Laboratory on improving the capture of mercury in flue gas through the use of dry sorbents and/or wet scrubbers. The results and conclusions to date from the Argonne research on dry sorbents can be summarized as follows: lime hydrates, either regular or high-surface-area, are not effective in removing elemental mercury; mercury removals are enhanced by the addition of activated carbon; mercury removals with activated carbon decrease with increasing temperature, larger particle size, and decreasing mercury concentration in the gas; chemical pretreatment (e.g., with sulfur or CaCl2) can greatly increase the removal capacity of activated carbon; chemically treated mineral substrates have the potential to be developed into effective and economical mercury sorbents; sorbents treated with different chemicals respond in significantly different ways to changes in flue-gas temperature.

Mercury-Containing Species and Carbon Dioxide Adsorption Studies on Inorganic Compounds Using Density Functional Theory

Author : BO GYEONG. KIM
Publisher :
ISBN 13 :
Total Pages : 466 pages
Book Rating : 4.:/5 (752 download)

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Book Synopsis Mercury-Containing Species and Carbon Dioxide Adsorption Studies on Inorganic Compounds Using Density Functional Theory by : BO GYEONG. KIM

Download or read book Mercury-Containing Species and Carbon Dioxide Adsorption Studies on Inorganic Compounds Using Density Functional Theory written by BO GYEONG. KIM and published by . This book was released on 2010 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this research is to obtain the adsorption mechanisms of toxic mercury-containing species (Hg, HgCl and HgCl2) and carbon dioxide (CO2) on inorganic solid surfaces using theoretically predicted results because experiments have been unable to unravel the involved issues. The understanding of the adsorption mechanisms of the mercury species and carbon dioxide from flue gases is important when considering mercury capture from coal-fired power plants, artisanal gold mining, and cement manufacturing industries. The current research attempts to explain each adsorption mechanism for mercury species, and those for carbon dioxide adsorption, on the surfaces through optimized geometries, energies and thermodynamic data. To investigate this research, density functional theory, which is one of useful tools for analyzing reactions on solid surfaces, was used to determine first principles-based theoretical adsorption models. Mainly, results from computational work indicate that mercury-containing species and carbon dioxide adsorption on calcium oxide surfaces and elemental mercury adsorption on a gehlenite surface are exothermic reactions. Calcium oxide is a promising adsorbent for oxidized mercury (HgCl and HgCl2), but not for elemental Hg. Interestingly, the elemental mercury, which is the major form (>90%) in the flue gases of the coal-combustion power plants, is chemisorbed on a gehlenite surface, which is partially composed of calcium oxide and comes from a mineral transition at high temperature. Strong adsorption on this inorganic sorbent is enhanced at high temperatures even though this adsorption process is exothermic. In addition, CaO surfaces are effective at capturing CO2, generating calcium carbonate compounds at flue gas temperatures, and water vapor enhances its adsorbability due to a larger CO2 adsorption energy. The current research shows that inorganic sorbents are not only effective in removing the elemental and oxidized forms of mercury but also in mineralizing CO2 at high temperatures into a solid form. The mercury species and carbon dioxide adsorption mechanisms investigated in this research may be utilized in the application of more efficient mercury and carbon dioxide control technologies. Future work will examine the reaction transition state and predict the kinetic data of the carbonation reactions, and, additionally, may prove the hypothesis that H2O molecules play a role as catalysts, increasing reaction rates.

Thermodynamic Considerations for Carbon Dioxide Removal from Flue Gases Issued from Coal Combustion

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (924 download)

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Book Synopsis Thermodynamic Considerations for Carbon Dioxide Removal from Flue Gases Issued from Coal Combustion by :

Download or read book Thermodynamic Considerations for Carbon Dioxide Removal from Flue Gases Issued from Coal Combustion written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Field Test Program for Long-Term Operation of a COHPAC System for Removing Mercury from Coal-Fired Flue Gas

Author : Sharon Sjostrom
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (316 download)

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Book Synopsis Field Test Program for Long-Term Operation of a COHPAC System for Removing Mercury from Coal-Fired Flue Gas by : Sharon Sjostrom

Download or read book Field Test Program for Long-Term Operation of a COHPAC System for Removing Mercury from Coal-Fired Flue Gas written by Sharon Sjostrom and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With the Nation's coal-burning utilities facing the possibility of tighter controls on mercury pollutants, the U.S. Department of Energy is funding projects that could offer power plant operators better ways to reduce these emissions at much lower costs. Sorbent injection technology represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. It involves injecting a solid material such as powdered activated carbon into the flue gas. The gas-phase mercury in the flue gas contacts the sorbent and attaches to its surface. The sorbent with the mercury attached is then collected by the existing particle control device along with the other solid material, primarily fly ash. During 2001, ADA Environmental Solutions (ADA-ES) conducted a full-scale demonstration of sorbent-based mercury control technology at the Alabama Power E.C. Gaston Station (Wilsonville, Alabama). This unit burns a low-sulfur bituminous coal and uses a hot-side electrostatic precipitator (ESP) in combination with a Compact Hybrid Particulate Collector (COHPAC{reg_sign}) baghouse to collect fly ash. The majority of the fly ash is collected in the ESP with the residual being collected in the COHPAC{reg_sign} baghouse. Activated carbon was injected between the ESP and COHPAC{reg_sign} units to collect the mercury. Short-term mercury removal levels in excess of 90% were achieved using the COHPAC{reg_sign} unit. The test also showed that activated carbon was effective in removing both forms of mercury-elemental and oxidized. However, a great deal of additional testing is required to further characterize the capabilities and limitations of this technology relative to use with baghouse systems such as COHPAC{reg_sign}. It is important to determine performance over an extended period of time to fully assess all operational parameters. The project described in this report focuses on fully demonstrating sorbent injection technology at a coal-fired power generating plant that is equipped with a COHPAC{reg_sign} system. The overall objective is to evaluate the long-term effects of sorbent injection on mercury capture and COHPAC{reg_sign} performance. The work is being done on one-half of the gas stream at Alabama Power Company's Plant Gaston Unit 3 (nominally 135 MW). Data from the testing will be used to determine: (1) If sorbent injection into a high air-to-cloth ratio baghouse is a viable, long-term approach for mercury control; and (2) Design criteria and costs for new baghouse/sorbent injection systems that will use a similar, polishing baghouse (TOXECON{trademark}) approach.

Mercury Removal from Flue Gas by Aqueous Precipitation

Author : Feng Jiang
Publisher :
ISBN 13 : 9781267254580
Total Pages : 120 pages
Book Rating : 4.2/5 (545 download)

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Book Synopsis Mercury Removal from Flue Gas by Aqueous Precipitation by : Feng Jiang

Download or read book Mercury Removal from Flue Gas by Aqueous Precipitation written by Feng Jiang and published by . This book was released on 2012 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury is widely present in the environment in various forms, including elemental mercury, Hg and Hg2. As one of the heavy metals, mercury has drawn the public's concern due to its bio-accumulative nature and its adverse impact on human health. At the same time, concern for greenhouse gas release has also grown, leading to a range of carbon capture strategies. For example, Calera Corporation has developed a process named CMAP (Carbonate Mineralization by Aqueous Precipitation) that was designed to remove and sequester carbon dioxide (CO2) from the flue gas of coal-fired power plants using treated seawater to produce solid carbonates of calcium and magnesium. These solids can later be used as aggregates or cement in the concrete industry. Because of the process character, CMAP, and similar precipitation processes, shows the potential to capture some portion of the mercury as it traps CO2. It therefore could potentially be an integrated emission control strategy for industries. However, previous mercury removal studies focused on either dry techniques or acidic solution conditions, and a major uncertainty is how the high alkalinity in processes like Calera's may result in a different mercury capture mechanism. To examine this question in detail, in this study, a lab-scale liquid-gas scrubbing system is manufactured and installed. Simulated flue gas containing mercury, as well as CO2 is then processed by the scrubber and capture efficiencies examined. Elemental and oxidized mercury are injected into the test section through dedicated mercury generating systems. A PSA mercury analyzer is employed to monitor mercury concentration during the experiment. Sodium hydroxide and sodium carbonate solution are selected as typical candidates to remove mercury. Based on the test results collected with the sodium hydroxide solution, the CMAP process has relatively low elemental mercury removal efficiency, i.e. less than 20%, but can remove oxidized mercury at more than 90%. The sodium carbonate solution showed a similar extent of mercury removal. This performance is very similar to that of the traditional flue gas desulfurization process which is operated under acidic conditions at pH from 4 to 6. Equilibrium calculations by Visual MINTEQ predict the speciation of mercury in the liquid phase, and the predicted equilibrium result is in agreement with experimental data.

The Effects of Carbon-in-ash on Mercury Capture from Flue Gas

Author : Kyung Man Kim
Publisher :
ISBN 13 : 9781124107929
Total Pages : 152 pages
Book Rating : 4.1/5 (79 download)

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Book Synopsis The Effects of Carbon-in-ash on Mercury Capture from Flue Gas by : Kyung Man Kim

Download or read book The Effects of Carbon-in-ash on Mercury Capture from Flue Gas written by Kyung Man Kim and published by . This book was released on 2010 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury existing as a trace element in coal is an important pollutant because coal burning is increasing around the world for energy production and coal-fired plants are the largest anthropogenic source of mercury emission to the environment. Mercury behavior in the homogeneous conditions of cooling flue gas is characterized using equilibrium study and fundamental mercury kinetics depending on the time-temperature history. Up-to-date version of mercury oxidation based on quench rate is plotted with revised mercury mechanism. Slow quench rates show better mercury oxidation at the typical cooling rate in power plant. Mercury capture mostly occurs under heterogeneous conditions between sorbent particles and gaseous mercury, and this study is mainly devoted to understanding the role of carbon-in-ash on mercury capture from flue gas. Coal flyash samples are characterized by loss-on-ignition (LOI), surface area (BET) tests, and scanning electron microscopy (SEM). Flyash sorbents are injected using an in-flight configuration and then mercury concentration is measured by Hg CEMS. The unburned carbon is one main factor for capturing mercury. However, mercury uptake is shown to be relatively low when using flyash from high rank coal such as anthracite because of the small surface area coming from the non-porous structure. Therefore, when flyash is used as a sorbent for mercury capture, quantitative surface area should be compared and coal rank also should be considered. Non-carbon zeolite injection showed that carbon has physico-chemically favorable structure to capture mercury as well as creating high surface area with the ash. A detailed diffusion mechanism for the mercury capture process was examined using a relatively simple 1-D model. Porosity and Knudsen diffusivity are very important in intra-particle diffusion based on the investigation of sensitivity of diffusion factors. Under the conditions of this study, it appears that elemental mercury can be more readily captured than oxidized mercury because of its lower molecular weight.

Removal of Mercury from Coal-combustion Flue-gas

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (683 download)

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Book Synopsis Removal of Mercury from Coal-combustion Flue-gas by :

Download or read book Removal of Mercury from Coal-combustion Flue-gas written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion sources, including those using coal for fuel, contribute a significant fraction of total anthropogenic mercury emissions. Recent field studies have shown that current flue-gas cleanup (FGC) systems are relatively ineffective in controlling elemental mercury, which is a major component of the mercury emissions for many systems. Research at Argonne National Laboratory has been focused on techniques to enhance the capture of elemental mercury in existing FGC systems. For dry processes, these studies have included evaluation of activated carbons and investigation of sorbents based upon chemical pretreatment of low-cost mineral substrates. To enhance the ability of wet scrubbers to capture mercury, the studies have looked at the effects of improved mass transfer through both mechanical and chemical means, as well as the conversion of elemental mercury into more soluble species that can be easily absorbed.