Download or read book Experimental Investigation and Kinetic Modeling of Homogeneous Mercury Oxidation by Halogens written by Brydger Cauch and published by . This book was released on 2008 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental and Kinetic Modeling Investigation of Gas phase Mercury Oxidation Reactions with Chlorine written by Andrew Rodger Fry and published by . This book was released on 2008 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Homogeneous Forcing of Mercury Oxidation to Provide Low Cost Capture written by John C. Kramlich and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxidized mercury formed in combustors (e.g., HgCl{sub 2}) is much more easily captured in existing pollution control equipment (e.g., wet scrubbers for SO{sub 2}) than elemental mercury. This is principally due to the high solubility of the oxidized form in water. Work over the last several years in our laboratory and elsewhere has identified the general outlines of the homogeneous chemistry of oxidation. The goal of the work reported here is to make use of this knowledge of the oxidation mechanism to devise simple and inexpensive ways to promote the oxidation. The hypothesis is that simple fuels such as hydrogen or CO can promote oxidation via the free radicals they generate during their decomposition. These free radicals then promote the formation of Cl from HCl via reactions such as OH+HCl {yields} H{sub 2}O+Cl. The Cl (and Cl{sub 2} derived from Cl recombination) are considered the principal oxidizing species. In our studies, mercury vapor is exposed to HCl under isothermal conditions in a gas containing N{sub 2}, O{sub 2}, and H{sub 2}O. The experiments systematically explore the influence of reaction temperature, HCl concentration, and H{sub 2}O concentration. These baseline conditions are then perturbed by the addition of varying amounts of H{sub 2}, CO, and H{sub 2}/CO added jointly. The following report presents the results of a literature review associated with the dissertation of the student supported by the program. This outlines the state-of-the-art in mercury behavior. It then describes the experimental facilities and the results of tests involving the promotion of the oxidation reaction by H{sub 2}, CO, and H{sub 2}/CO combinations. These results indicate a substantial enhancement of oxidation under isothermal conditions at 900-1000 K, while the additives inhibit oxidation at 1200 K. The next step is to determine whether the existing chemical kinetic models of mercury oxidation are capable of reproducing this behavior. These models can then be used to extrapolate the findings to nonisothermal conditions typical of boiler environments. This would provide guidance on where to inject the oxidation promoters in a practical boiler, and how much promoter is required.

Download or read book Analysis of Halogen Mercury Reactions in Flue Gas written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxidized mercury species may be formed in combustion systems through gas-phase reactions between elemental mercury and halogens, such as chorine or bromine. This study examines how bromine species affect mercury oxidation in the gas phase and examines the effects of mixtures of bromine and chlorine on extents of oxidation. Experiments were conducted in a bench-scale, laminar flow, methane-fired (300 W), quartz-lined reactor in which gas composition (HCl, HBr, NO(subscript x), SO2) and temperature profile were varied. In the experiments, the post-combustion gases were quenched from flame temperatures to about 350 C, and then speciated mercury was measured using a wet conditioning system and continuous emissions monitor (CEM). Supporting kinetic calculations were performed and compared with measured levels of oxidation. A significant portion of this report is devoted to sample conditioning as part of the mercury analysis system. In combustion systems with significant amounts of Br2 in the flue gas, the impinger solutions used to speciate mercury may be biased and care must be taken in interpreting mercury oxidation results. The stannous chloride solution used in the CEM conditioning system to convert all mercury to total mercury did not provide complete conversion of oxidized mercury to elemental, when bromine was added to the combustion system, resulting in a low bias for the total mercury measurement. The use of a hydroxylamine hydrochloride and sodium hydroxide solution instead of stannous chloride showed a significant improvement in the measurement of total mercury. Bromine was shown to be much more effective in the post-flame, homogeneous oxidation of mercury than chlorine, on an equivalent molar basis. Addition of NO to the flame (up to 400 ppmv) had no impact on mercury oxidation by chlorine or bromine. Addition of SO2 had no effect on mercury oxidation by chlorine at SO2 concentrations below about 400 ppmv; some increase in mercury oxidation was observed at SO2 concentrations of 400 ppmv and higher. In contrast, SO2 concentrations as low as 50 ppmv significantly reduced mercury oxidation by bromine, this reduction could be due to both gas and liquid phase interactions between SO2 and oxidized mercury species. The simultaneous presence of chlorine and bromine in the flue gas resulted in a slight increase in mercury oxidation above that obtained with bromine alone, the extent of the observed increase is proportional to the chlorine concentration. The results of this study can be used to understand the relative importance of gas-phase mercury oxidation by bromine and chlorine in combustion systems. Two temperature profiles were tested: a low quench (210 K/s) and a high quench (440 K/s). For chlorine the effects of quench rate were slight and hard to characterize with confidence. Oxidation with bromine proved sensitive to quench rate with significantly more oxidation at the lower rate. The data generated in this program are the first homogeneous laboratory-scale data on bromine-induced oxidation of mercury in a combustion system. Five Hg-Cl and three Hg-Br mechanisms, some published and others under development, were evaluated and compared to the new data. The Hg-halogen mechanisms were combined with submechanisms from Reaction Engineering International for NO(subscript x), SO(subscript x), and hydrocarbons. The homogeneous kinetics under-predicted the levels of mercury oxidation observed in full-scale systems. This shortcoming can be corrected by including heterogeneous kinetics in the model calculations.

Download or read book Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed Bed and Entrained Flow Reactor written by and published by . This book was released on 2009 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and intraparticle diffusion. The Freundlich isotherm more accurately described in-flight mercury capture. Using these parameters, very little intraparticle diffusion was evident. Consistent with other data, smaller particles resulted in higher mercury uptake due to available surface area. Therefore, it is important to capture the particle size distribution in the model. At typical full-scale sorbent feed rates, the calculations underpredicted adsorption, suggesting that wall effects can account for as much as 50 percent of the removal, making it an important factor in entrained-mercury adsorption models.

Download or read book Mercury Control written by Evan J. Granite and published by John Wiley & Sons. This book was released on 2015-01-20 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: This essential handbook and ready reference offers a detailed overview of the existing and currently researched technologies available for the control of mercury in coal-derived gas streams and that are viable for meeting the strict standards set by environmental protection agencies. Written by an internationally acclaimed author team from government agencies, academia and industry, it details US, EU, Asia-Pacific and other international perspectives, regulations and guidelines.

Download or read book Development of a Chemical Kinetic Model for the Homogeneous Oxidation of Mercury by Chlorine Species written by Rebecca North Sliger and published by . This book was released on 2001 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 21st European Symposium on Computer Aided Process Engineering written by and published by Elsevier. This book was released on 2011-06-10 with total page 2086 pages. Available in PDF, EPUB and Kindle. Book excerpt: The European Symposium on Computer Aided Process Engineering (ESCAPE) series presents the latest innovations and achievements of leading professionals from the industrial and academic communities. The ESCAPE series serves as a forum for engineers, scientists, researchers, managers and students to present and discuss progress being made in the area of computer aided process engineering (CAPE). European industries large and small are bringing innovations into our lives, whether in the form of new technologies to address environmental problems, new products to make our homes more comfortable and energy efficient or new therapies to improve the health and well being of European citizens. Moreover, the European Industry needs to undertake research and technological initiatives in response to humanity's "Grand Challenges," described in the declaration of Lund, namely, Global Warming, Tightening Supplies of Energy, Water and Food, Ageing Societies, Public Health, Pandemics and Security. Thus, the Technical Theme of ESCAPE 21 will be "Process Systems Approaches for Addressing Grand Challenges in Energy, Environment, Health, Bioprocessing & Nanotechnologies."

Download or read book Fundamentals of Mercury Oxidation in Flue Gas written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project is to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involves both experimental and modeling efforts. The team is comprised of the University of Utah, Reaction Engineering International, and the University of Connecticut. The objective is to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters to be studied include HCl, NO(subscript x), and SO2 concentrations, ash constituents, and temperature. This report summarizes Year 2 results for the experimental and modeling tasks. Experiments in the mercury reactor are underway and interesting results suggested that a more comprehensive look at catalyzed surface reactions was needed. Therefore, much of the work has focused on the heterogeneous reactions. In addition, various chemical kinetic models have been explored in an attempt to explain some discrepancies between this modeling effort and others.

Download or read book A Study of Mercury Oxidation and the Development of a Global Predictive Kinetic Model written by Hans Agarwal and published by . This book was released on 2006 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: These reaction rate constants were further used to predict experimental data from eleven experimental mercury data sources in the literature. It was found that the predictions from the model correspond very well with the observed published data. Over 90% of the 146 data points were predicted very well.

Download or read book The Kinetics of Homogeneous Vapor Phase Reactions of Mercury and Halogens written by Henry C. Martin and published by . This book was released on 1936 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals of Mercury Oxidation in Flue Gas written by Joseph Helble and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project is to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involves both experimental and modeling efforts. The team is comprised of the University of Utah, Reaction Engineering International, and the University of Connecticut. The objective is to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters to be studied include HCl, NO{sub x}, and SO{sub 2} concentrations, ash constituents, and temperature. This report summarizes Year 3 results for the experimental and modeling tasks. Experiments have been completed on the effects of chlorine. However, the experiments with sulfur dioxide and NO, in the presence of water, suggest that the wet-chemistry analysis system, namely the impingers, is possibly giving erroneous results. Future work will investigate this further and determine the role of reactions in the impingers on the oxidation results. The solid-phase experiments have not been completed and it is anticipated that only preliminary work will be accomplished during this study.

Download or read book Computational and Experimental Studies of Mercury Homogeneous and Heterogeneous Oxidation in Flue Gases Derived Form Coal fired Power Plants written by Junru Li and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational and Experimental Studies of Mercury Homogeneous and Heterogeneous Oxidation in Flue Gases Derived from Coal fired Power Plants written by Junru Li and published by . This book was released on 2010 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanisms of Atmospheric Oxidation of the Alkanes written by Jack G Calvert and published by Oxford University Press. This book was released on 2008-09-15 with total page 1005 pages. Available in PDF, EPUB and Kindle. Book excerpt: An international team of eminent atmospheric scientists have prepared Mechanisms of Atmospheric Oxidation of the Alkanes as an authoritative source of information on the role of alkanes in the chemistry of the atmosphere. The book includes the properties of the alkanes and haloalkanes, as well as a comprehensive review and evaluation of the existing literature on the atmospheric chemistry of the alkanes and their major atmospheric oxidation products, and the various approaches now used to model the alkane atmospheric chemistry. Comprehensive coverage is given of both the unsubstituted alkanes and the many haloalkanes. All the existing quality measurements of the rate coefficients for the reactions of OH, Cl, O(3P), NO3, and O3 with the alkanes, the haloalkanes, and their major oxidation products have been reviewed and evaluated. The expert authors then give recommendations of the most reliable kinetic data. They also review the extensive literature on the mechanisms and rates and modes of photodecomposition of the haloalkanes and the products of atmospheric oxidation of the alkanes and the haloalkanes, and make recommendations for future use by atmospheric scientists. The evaluations presented allow an extrapolation of the existing kinetic and photochemical data to those alkanes and haloalkanes that are as yet unstudied. The current book should be of special interest and value to the modelers of atmospheric chemistry as a useful input for development of realistic modules designed to simulate the atmospheric chemistry of the alkanes, their major oxidation products, and their influence on ozone and other trace gases within the troposphere.

Download or read book Canadian Journal of Chemistry written by and published by . This book was released on 2008-07 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mercury Contaminated Sites written by Ralf Ebinghaus and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: An up-to-date overview of the characterization, risk assessment and remediation of mercury-contaminated sites. The book summarizes, for the first time, works from Europe, Russia and the American continent, and review chapters are supplemented by detailed, international case studies.