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Optical properties of flyash

Description: The chemical composition and size distribution of representative flyashes are being measured by appropriate microanalytical techniques to provide information required. Measurements of the infrared optical constants (i.e., the complex refractive index m = n - ik) of synthetic slags are being made as a function of wavelength and temperature for controlled compositions. Particular attention will be given to the contribution of the Fe{sub 2}O{sub 3} content and its valence state. The data is being reduced to yield formulae giving the complex refractive index over relevant ranges of wavelength and temperature, as a function of the relevant metal oxide constituents. A benchscale experiment is planned to compare the measured radiant properties of a dispersion of well-characterized ash with computations based on data developed under the first two tasks.
Date: July 1, 1990
Creator: Self, S.A.
Partner: UNT Libraries Government Documents Department

Optical properties of flyash

Description: The purpose of this task is to validate the whole approach adopted in this program. Specifically, this bench-scale experiment is intended to compare the measured optical/radiative properties of a dispersion of well characterized ash with those calculated on the basis of the known size/composition distribution using the correlation formulae relating the composition and complex refractive index resulting from measurements on bulk samples of synthetic slag. Considerable thought has been given to the various possible approaches to satisfying the objectives of this task. Several experiments were done to guide our design of an apparatus for measuring the scattering and absorption properties of dispersions of flyash. As a result of these experiments, and from extensive prior experience in connection with research on electrostatic precipitation, it has been determined that there is no satisfactory way to satisfy the aims of this task using a gaseous dispersion of flyash because it is not possible to adequately disperse and deagglomerate flyash into a gas stream. Unless the ash is adequately dispersed, as it exists in the radiant boiler of a pulverized coal-fired combustion system, one cannot expect calculations, based on Mie calculations for a dispersion of spheres to properly agree with laboratory measurements. For these reasons, our design efforts are based on making measurements on a dispersion of flyash in liquid, for which our experience shows we can obtain stable, well-deagglomerated dispersions of ash. Because there is not single liquid which is adequately transparent over the wavelength range 1--12 {mu}m, we plan to use a combination of three liquids, C Cl{sub 4}, C S{sub 2} and bromoform to cover the full range. Windows of BaF{sub 2} will be used to contain the liquid suspension in an absorption/scattering cell.
Date: July 1, 1989
Creator: Self, S.A.
Partner: UNT Libraries Government Documents Department

Characterization of fly ash from coal combustion

Description: Fly ash derived from coal combustion contains predominantly spherical particles which consist of an insoluble aluminosilicate glass containing several mineral impurities. An outer layer, 50 to 300 A thick, is rich in many potentially toxic trace elements in the form of simple and complex sulfates. This layer, which is soluble in water, contains essentially all of the particulate sulfur present in fly ash in the form of sulfate. The actual mechanism(s) of formation of particulate sulfate salts are ill-defined but probably involve adsorption of condensation of gaseous sulfur species onto fly ash surfaces within the power plant stack system.
Date: January 1, 1978
Creator: Natusch, D. F.S.
Partner: UNT Libraries Government Documents Department

Multinuclear NMR approach to coal fly ash characterization

Description: This report describes the application of various nuclear magnetic resonance (NMR) techniques to study the hydration kinetics and mechanisms, the structural properties, and the adsorption characteristics of coal fly ash. Coal fly ash samples were obtained from the Dave Johnston and Laramie River electric power generating plants in Wyoming. Hydrogen NMR relaxation times were measured as a function of time to observe the kinetics of hydration for the two coal fly ashes at different temperatures and water-to-cement ration. The kinetic data for the hydrated coal fly ashes were compared to the hydration of portland cement. The mechanism used to describe the kinetic data for the hydration of portland cement was applied, with reservation, to describe the hydration of the coal fly ashes. The results showed that the coal fly ashes differ kinetically from that of portland cement and from each other. Consequently, both coal fly ashes were judged to be poorer cementitious materials than portland cement. Carbon-13 NMR CP/MAS spectra were obtained for the anhydrous coal fly ashes in an effort to determine the type of organic species that may be present, either adsorbed on the surface or entrained.
Date: September 1, 1991
Creator: Netzel, D.A.
Partner: UNT Libraries Government Documents Department

Fly ash from Texas lignite and western subbituminous coal: a comparative characterization

Description: As examples, we use two Jackson group lignites from Atascosa and Fayette Counties, Texas, and a Green River Region subbituminous coal from Routt County, Colorado. The composition of individual fly ash particles was determined using scanning electron microscopy and electron microprobe, with support from x-ray diffraction of bulk ash. Using particle sample populations large enough to permit statistical treatment, we describe the relationship of composition to particle size and the correlation between elemental concentrations, as well as particle size and composition distributions. Correlations are displayed as data maps which show the complete range of observed variation among these parameters, emphasizing the importance of coal variability. We next use this data to produce a population distribution of ash particle resistivities calculated with Bickelhaupt's model. The relationship between calculated resistivity and particle size is also displayed, and the results are compared with measured values. 7 figures.
Date: January 1, 1982
Creator: Sears, D. R.; Benson, S. A.; McCollor, D. P. & Miller, S. J.
Partner: UNT Libraries Government Documents Department

Mechanisms governing fine particulate emissions from coal flames

Description: The principal activities during this quarter involved the global experiments. Ash was sampled from a number of coals (of varying rank) as a function of oxygen concentration. Proximate analyses of the coals were performed. Analyses of the data were performed using the breakup model. When fitting the data with the breakup model, higher rank coals were found to require fewer ash particles per coal particle than the lower ranked coals. Deviations of the measured size distribution from the simple breakup model were examined. During this quarter preparation for the mechanistic experiments was begun. This work involves cleaning and sizing three coals and measuring the particle size distribution of ashes from these various cuts of coals. This work will continue during the next reporting quarter.
Date: August 1, 1989
Creator: Newton, G.H.; Schieber, C.; Socha, R.G.; Clark, W.D. & Kramlich, J.C.
Partner: UNT Libraries Government Documents Department

Mechanisms governing fine particulate emissions from coal flames

Description: During this reporting period the global experiments were concluded. The final activities under these experiments involved measuring mineral content of coals as a function of coal particle size. The principal activities during this quarter involved the mechanistic experiments. Three baseline coals were cleaned and two of these sized. The ash from these various cuts were sampled from a bench scale reactor. The ash size distributions were compared to distributions predicted by the breakup model.
Date: October 1, 1989
Creator: Newton, G.H.; Schieber, C.; Socha, R.G.; Clark, W.D. & Kramlich, J.C.
Partner: UNT Libraries Government Documents Department

Mechanisms governing fine particulate emissions from coal flames

Description: The overall objectives of this project are to provide a basic understanding of the principal processes that govern fine particulate formation in pulverized coal flames. This understanding is to be used to develop a model (or models) which will predict the yield and size distribution of fine particulates as a function of coal type, coal processing, and combustion conditions. The goal of the model is to provide an engineering tool that will enable the practitioner to estimate the consequences of design decisions and fuel selection on the fine particulate yield. The practitioner can then make rational decisions regarding the required technology and costs associated with effluent cleanup while still in the design phase.
Date: February 1, 1989
Creator: Kramlich, J.C.; Newton, G.H.; Socha, R.G. & Clark, W.D.
Partner: UNT Libraries Government Documents Department

Mechanisms governing fine particulate emissions from coal flames

Description: The overall objective of this project is to provide a basic understanding of the principal processes that govern fine particulate formation in pulverized coal flames. This understanding is to be sued to develop a model (or models) which will predict the yield and size distribution of fine particulate matter as a function of coal type, coal processing, and combustion conditions. The goal of the model is to provide an engineering tool that will enable the practitioner to estimate the consequences of deign decisions and fuel selection on the fine particulate yield. The practitioner can then make rational decisions regarding the required technology and costs associated with effluent cleanup while still in the design phase.
Date: May 1, 1989
Creator: Newton, G.H.; Schieber, C.; Socha, R.G.; Clark, W.D. & Kramlich, J.C.
Partner: UNT Libraries Government Documents Department

Mechanisms governing fine particulate emissions from coal flames

Description: The primary objective of this program was to provide a basic understanding of the principal processes that govern the formation of particulate matter in the 0.5--10 {mu}m size range in pulverized coal flames. The mechanism that produces ash particles in this size range is not clear. Particle sizes smaller than the 0.5--10 {mu}m size range are generally accepted to result from a vaporization/condensation mechanism while particles larger than this size result from the coalescence of ash in coal particles which may breakup as they burn. This program combined experimental and theoretical studies to understand the mechanisms which control the production of ash in the 0.5--10 {mu}m size range. (VC)
Date: April 1, 1990
Creator: Newton, G.H.; Schieber, C.; Socha, R.G. & Kramlich, J.C.
Partner: UNT Libraries Government Documents Department

Hydration reactions of C/sub 3/A contained in an unusual flyash

Description: Flyashes produced from certain lignite and sub-bituminous coals have high contents of analytical CaO, presumably derived from limestone within the coal deposits. In the US a special category, Class C flyash has been designated for these materials. The mineralogy of the non-glassy portions of some of these flyashes is different from conventional flyashes, and in the material described C/sub 3/A, free lime, and anhydrite are all present. The flyash sets rapidly when mixed with water, and produces ettringite and C/sub 4/ASH/sub 12/. The unique spherical morphology of the flyash grains makes the morphological relationships between the hydration products and the unhydrated material unusually clear. The early reactions are similar to those of C/sub 3/A in portland cement, and the ash might serve as a useful model system for the study of the influence of various admixtures and other substances on C/sub 3/A reactions and setting behavior. Presumably ettringite and C/sub 4/ASH/sub 12/ are also produced when flyashes similar to the one studied are incorporated in concrete, and their production should enhance early strength development.
Date: January 1, 1980
Creator: Diamond, S.
Partner: UNT Libraries Government Documents Department

Radiative properties of ash and slag

Description: Thermal radiation plays a key role in the operation and efficiency of combustion systems, accounting for over 90% of the heat transfer. The analysis of radiative heat transfer in coal-fired boilers, combustion chambers and other energy systems requires accounting for the effects of inorganic deposits on bounding surfaces and of entrained particulates, such as pulverized coal, char, and fly-ash. These effects can be predicted; however, the accuracy in predicting the radiative properties of entrained pyrolysis (ash) and deposit layers (slag) is limited by inaccurate knowledge of the physical/chemical properties of the materials over a range of material temperatures and radiative wavelengths that is representative of conditions in practical combustion systems. The objective of this project is to make laboratory measurements of the radiative properties of extracted ash and slag deposit samples. During this quarter, measurements were continued for fused, tintered and powdery deposits.
Date: October 1, 1989
Creator: Solomon, P. R. & Markham, J. R.
Partner: UNT Libraries Government Documents Department

Optical properties of flyash

Description: In this research program, we have adopted the approach that by measuring fundamental properties (i.e, the complex refractive index, m) of the fly ash which participates in the radiation transfer, we can use well established theoretical principles (Mie theory) to compute the radiative properties of dispersions of fly ash as found in coal combustors. With this approach one can, understand the underlying principles that affect the radiative properties of an ash dispersion and more confidently predict how variations in the characteristics of the ash dispersion cause variations in its radiative properties. An important criterion in this approach is that the fly ash particles be spherical, homogeneous, and isotropic. Fortunately, fly ash particles are formed at high temperatures at which most of them are molten, leading primarily to spherical particles. Furthermore, one should expect that molten particles will be reasonably homogeneous and isotropic. On cooling, most fly ash particles form glassy spheres which are homogeneous and isotropic. Some ash particles form hollow shells (cenospheres) while others form as particles with bubbles'' or voids, but most fly ash particles are well approximated as homogeneous isotropic spheres. In the following sections we review some of the underlying principles that affect the radiative properties of fly ash dispersions and report on progress that has been made during the past quarter.
Date: April 1, 1990
Creator: Self, S. A.
Partner: UNT Libraries Government Documents Department

Mechanisms governing fine particulate emissions from coal flames

Description: Efforts in this period focused on refining the plans for engineering analysis and fundamental experiments based on the results of a literature review, and modifying the Malvern laser diffraction particle sizer to operate at particle sizes down to 0.5 microns. The engineering analysis plan is to concentrate on development of new models and adaptation of existing models for fine particulate formation by three categories of mechanisms: particle breakup/ash coalescence; direct passage, fragmentation, or agglomeration of extraneous mineral matter; and bubble formation/breakup. The plan for fundamental experiments is to develop a fast, online, optical particle sizing technique which will span the 0.5 to 10 micron size range of interest; to perform global experiments to identify the important parameters affecting fine particle formation; and to perform mechanistic experiments to test specific hypotheses about the mechanisms which control fine particle formation in coal combustion.
Date: April 1, 1988
Creator: Clark, W.D.; Chen, S.L.; Kramlich, J.C.; Newton, G.H.; Ruth, L.A. (Energy and Environmental Research Corp., Irvine, CA (United States)) & Samuelsen, G.S. (California Univ., Irvine, CA (United States))
Partner: UNT Libraries Government Documents Department

Sorbate characteristics of fly ash. Semi annual progress report

Description: This one year investigation is concerned with relating the sorbent characteristics of fly ash produced from test coal obtained from 19 mines located in Virginia, West Virginia and Pennsylvania. Six of the test coals and their respective fly ashes have been sampled and boiler conditions monitored in P.S.E. and G. coal fired boilers operated under minimum, intermediate and full power. Major, minor and trace elemental analysis as well as Mossbauer spectra of three of the coals and their respective ashes have been completed. The atom composition of the surface of these fly ashes has also been determined by ESCA. The pH and concentration of the major, minor and trace elements that leach out of the fly ash initially have been determined on the fly ashes produced from the Militant, Deep Hollow and Wellmore Cactus coals. All leachate samples to date exhibited an acidic pH. This leaching essentially ceases as the pH approached neutral conditions. This was found to occur after 4 liters of water was passed through each fly ash sample in a lysimeter. The lysimeter studies to define the sorbent characteristics of the fly ashes have not been completed yet.
Date: January 1, 1980
Creator: Liskowitz, J.W.
Partner: UNT Libraries Government Documents Department

Radiative properties of ash and slag

Description: Thermal radiation plays a key role in the operation and efficiency of combustion systems, accounting for over 90% of the heat transfer. The analysis of radiative heat transfer in coal-fired boilers, combustion chambers and other energy systems requires accounting for the effects of inorganic deposits on bounding surfaces and of entrained particulates, such as pulverized coal, char, and fly-ash. These effects can be predicted; however, the accuracy in predicting the radiative properties of entrained pyrolysis (ash) and deposit layers (slag) is limited by inaccurate knowledge of the physical/chemical properties of the materials over a range of material temperatures and radiative wavelengths that is representative of conditions in practical combustion systems. The objective of this project is to make laboratory measurements of the radiative properties of extracted ash and slag deposit samples.
Date: March 1, 1990
Creator: Solomon, P. R. & Markham, J. R.
Partner: UNT Libraries Government Documents Department

Structure of coal: new approaches to characterizing organonitrogen and organosulfur functionalities in coal and coal liquids. Final report. [Finnigan triple quadrupole mass spectrometers]

Description: This report describes the application of tandem mass spectrometry (MS/MS) to the analysis of coal-related materials. A Finnigan Triple State Quadrupole mass spectrometer was used for most of the results obtained in this study. Both collision energy (0 to 30 eV) and collision gas pressure (0 to 2.5 mtorr, typically argon) have significant effects on the spectra. Increasing the collision energy or collision pressure results in an increased fragmentation of the selected ion. The analytical utility of different chemical ionization (CI) reagent gases is shown. The MS/MS spectra of a selected ion obtained by isobutane and ammonia CI are identical, which paves the way for development of MS/MS libraries. A library is being developed especially for the analysis of coal-related materials. Three principal MS/MS scan modes (daughter, parent and neutral loss) are utilized in the analysis of coal-related materials. Parent and neutral loss scans characterize the complex mixture for particular chemical moieties (functional groups, structure type), while daughter scans are used for identification of specific components. SRC II was the principal sample studied by CI. Laser desorption methodology for coal analysis was developed. Other fuel-related materials were examined to generalize the analytical methodology being developed for the coal-related materials, including shale oil and diesel exhaust particulates. 35 references, 50 figures, 3 tables.
Date: January 1, 1983
Creator: Cooks, R.G.
Partner: UNT Libraries Government Documents Department

Automated on-line determination of PPB levels of sodium and potassium in low-Btu coal gas and fluidized bed combustor exhaust by atomic emission spectrometry

Description: The Morgantown Energy Technology Center (METC), US Department of Energy, is involved in the development of processes and equipment for production of low-Btu gas from coal and for fluidized bed combustion of coal. The ultimate objective is large scale production of electricity using high temperature gas turbines. Such turbines, however, are susceptible to accelerated corrosion and self-destruction when relatively low concentrations of sodium and potassium are present in the driving gas streams. Knowledge and control of the concentrations of those elements, at part per billion levels, are critical to the success of both the gas cleanup procedures that are being investigated and the overall energy conversion processes. This presentation describes instrumentation and procedures developed at the Ames Laboratory for application to the problems outlined above and results that have been obtained so far at METC. The first Ames instruments, which feature an automated, dual channel flame atomic emission spectrometer, perform the sodium and potassium determinations simultaneously, repetitively, and automatically every two to three minutes by atomizing and exciting a fraction of the subject gas sample stream in either an oxyhydrogen flame or a nitrous oxide-acetylene flame. The analytical results are printed and can be transmitted simultaneously to a process control center.
Date: January 1, 1981
Creator: Haas, W.J. Jr.; Eckels, D.E.; Kniseley, R.N. & Fassel, V.A.
Partner: UNT Libraries Government Documents Department

Trace element characterization of coal wastes. Fourth annual progress report, October 1, 1978-September 30, 1979

Description: In the past year assessment studies of low-sulfur coal wastes from the Appalachian Region have been continued. These included mineralogical and trace elemental analyses on these materials and studies of their weathering and leaching behavior. Although the concentrations of the acid-forming minerals (pyrite and marcasite) were very low, leachates were quite acid (pH < 3) with concomitant trace element (Al, Mn, Fe, Ni, Cu) concentration elevation. As part of the overall assessment of the degree of environmental concern associated with acidic coal waste drainages, bioassay studies were performed. These revealed that coal wastes and their leachates are toxic to fresh water algae, fathead minnows, and one species of fresh-water flea. Laboratory experiments to identify control options for the coal wastes and their drainages have been focused on predisposal and codisposal treatments of the waste, with technical and economic evaluations being performed on the most promising options. One of the most promising control methods is pretreatment of the waste with a lime/limestone mixture; this produces a waste with no acid-forming tendencies for times up to several months, during which time it may be possible to dispose of the treated waste in a nonreactive environment. The cost of this option is comparable to that of the commonly used lime neutralization of the acid drainage. Other experiments have investigated, in considerable detail, the economic and environmental advantages and disadvantages of codisposing the wastes with 37 naturally occurring soils and industrial wastes. These methods look promising only under certain conditions, but are in general an order of magnitude less effective than existing controls or the lime/limestone disposal method.
Date: April 1, 1981
Creator: Williams, J.M.; Bertino, J.P.; Jones, M.M.; Wagner, P.; Wanek, P.L.; Wangen, L.E. et al.
Partner: UNT Libraries Government Documents Department

Low-rank coal research under the UND/DOE cooperative agreement. Quarterly technical progress report, April 1983-June 1983

Description: Progress reports are presented for the following tasks: (1) gasification wastewater treatment and reuse; (2) fine coal cleaning; (3) coal-water slurry preparation; (4) low-rank coal liquefaction; (5) combined flue gas cleanup/simultaneous SO/sub x/-NO/sub x/ control; (6) particulate control and hydrocarbons and trace element emissions from low-rank coals; (7) waste characterization; (8) combustion research and ash fowling; (9) fluidized-bed combustion of low-rank coals; (10) ash and slag characterization; (11) organic structure of coal; (12) distribution of inorganics in low-rank coals; (13) physical properties and moisture of low-rank coals; (14) supercritical solvent extraction; and (15) pyrolysis and devolatilization.
Date: January 1, 1983
Creator: Wiltsee, Jr., G. A.
Partner: UNT Libraries Government Documents Department