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Measurements of microwave transmission characteristics through various configurations of fluidized bed materials

Description: The feasibility of developing a microwave diagnostic system for measurement of bubbles in a fluidized bed combustion system has been experimentally investigated. Experiments were performed in a simple waveguide geometry, using microwave frequencies from 2.4 to 3.9 GHz. Styrofoam spacers were used to simulate bubbles in bed materials, such as Greer limestone. The results show that it is feasible to develop a diagnostic system based on microwave transmission through a system consisting of gaps in a limestone media, such as a fluidized bed. The gap has been shown to perturb the transmitted power, and to be very sensitive to bubble and bed material dimensions. Resonance effects are shown to occur when dimensions are integer multiples of a quarter wavelength.
Date: May 1, 1980
Partner: UNT Libraries Government Documents Department

Quarterly technical progress report, April-June 1982

Description: Progress reports are presented for the following tasks: (1) preparation of low-rank coals; application of liquefaction processes to low-rank coals; (2) slagging fixed-bed gasification; (3) atmospheric fluidized-bed combustion of low-rank coal; (4) ash fouling and combustion modification for low-rank coal; (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 and disposal; and (9) exploratory research.
Date: April 1, 1984
Partner: UNT Libraries Government Documents Department

Advanced atomization concept for CWF burning in small combustors, Phase 2

Description: The program describes a concept referred to as opposed-jet atomization, which is particularly applicable to coal-water fuel (CWF). In the present atomizer design, two opposed jets of CWF are directed at each other and externally encounter a perpendicular blast of air at the collision point to create a spray of much finer droplets. The present Phase 2 program involved further evaluation of the opposed-jet atomizer performance and related tasks.
Date: December 1, 1991
Creator: McHale, E.T. & Heaton, H.L.
Partner: UNT Libraries Government Documents Department

Full-Scale Demonstration Low-NOx Cell Burner retrofit

Description: The overall objective of the Full-Scale Low-NOx Cell (LNC) Burner Retrofit project is to demonstrate the cost-effective reduction of NOx generated by a large, base-loaded (70% capacity factor or greater), coal-fired utility boiler. Specific objectives include: at least 50% NOx reduction over standard two-nozzle cell burners, without degradation of boiler performance or life; acquire and evaluate emission and boiler performance data before and after the retrofit to determine NOx reduction and impact on overall boiler performance; and demonstrate that the LNC burner retrofits are the most cost-effective alternative to emerging, or commercially- available NOx control technology for units equipped with cell burners. The focus of this demonstration is to determine maximum NOx reduction capabilities without adversely impacting plant performance, operation and maintenance.
Date: May 24, 1991
Partner: UNT Libraries Government Documents Department

Georgetown University atmospheric fluidized bed boiler cogeneration system

Description: This report presents the results of one year of operation of the cogeneration system capability of the Georgetown University coal- fired, atmospheric fluidized-bed (AFB) boiler. The AFB was designed and installed under a separate contract with the US Department of Energy. The AFB project funded by DOE to demonstrate that high sulfur coal could be burned in an environmentally acceptable manner in a urban environment such as Georgetown. In addition, operational data from the unit would assist the industry in moving directly into design and construction of commercially warranted industrial size AFB boilers. 9 figs., 3 tabs.
Date: August 1, 1991
Creator: Podbielski, V. & Shaff, D.P.
Partner: UNT Libraries Government Documents Department

Modeling of CWM droplet combustion. Final report

Description: The objective of the present study was to develop a one-dimensional, unsteady state model for coal-water mixture droplet combustion, and to compare the characteristic times for the various processes, such as water vaporization, devolatilization and char oxidation with available experimental data. A water film surrounding a spherical coal particle is considered to undergo vaporization by heat transfer from the hot air. After the water vaporization is complete, devolatilization begins. This process is assumed to be kinetically controlled. Water vaporization and devolatilization processes are modeled by using a hybrid Eulerian-Lagrangian method to obtain the properties of the gas-phase and the condensed-phase. An explicit finite difference scheme is used to solve the Eulerian gas-phase equation where as a Runga-Kutta scheme is employed to solve the Lagrangian condensed-phase equations. The predicted characteristic times for water vaporization is in good agreement with values proposed in the literature. At the present time there is insufficient data to draw any conclusions on the model. Methods are proposed to refine the simple kinetic model which takes into account pore diffusion and mass transfer for devolatilization and char oxidation. 9 references, 12 figures.
Date: October 1, 1983
Creator: Pandalai, K.; Aggarwal, S. & Sirignano, W.
Partner: UNT Libraries Government Documents Department

Experimental studies on the group ignition of a cloud of coal particles

Description: The primary objectives of this work are to formulate a model to simulate transient coal pyrolysis, ignition, and combustion of a cloud of coal particles and to compare results of the program with those reported in the literature elsewhere. The present work is reported in the following order. An introduction to group combustion is given followed by a review of earlier works. Next, the relevance of the present work to practical application and spray combustion modeling is discussed. A group combustion model is then presented for a spherical cloud of coal particles along with a set of dimensional and nondimensional equations. Finally, nonsteady results are generated for pyrolysis, ignition, and combustion of a cloud of coal particles. (VC)
Date: January 1, 1992
Creator: Annamalai, K.; Ruiz, M.; Vadakkath, A. & Gopalakrishnan, C.
Partner: UNT Libraries Government Documents Department

Experimental studies on the group ignition of a cloud of coal particles: Volume 2, Pyrolysis and ignition modeling

Description: The primary objectives of this work are to formulate a model to simulate transient coal pyrolysis, ignition, and combustion of a cloud of coal particles and to compare results of the program with those reported in the literature elsewhere.
Date: January 1, 1992
Creator: Annamalai, K. & Ryan, W.
Partner: UNT Libraries Government Documents Department

Combustion of calcium-exchanged coal. First quarterly report

Description: The work performed during this first period includes equipment modification, development of analytical methods, oxidative pretreatment runs and combustion runs. The coal feeding section of an existing furnace was modified for uninterrupted feeding and better control of residence time. Analytical methods for sulfur and calcium in the coal and ash and for gaseous SO/sub 2/ were standardized. Oxidative pretreatment experiments were conducted in a fluidized bed at temperatures about 200/sup 0/C to evaluate the potential of this method for increasing the ion exchange capacity of coals and determine the accompanying loss of heating value. Combustion experiments were carried out at very high particle temperatures (2000/sup 0/K) at which a large fraction of the calcium additive was vaporized while 50 to 80% of the sulfur evolved as sulfur oxide. Continuing combustion experiments will be conducted at lower particle temperatures.
Date: February 10, 1984
Creator: Gavalas, G.R. & Flagan, R.C.
Partner: UNT Libraries Government Documents Department

Industrial application fluidized bed combustion. Category III: indirect fired heaters. Quarterly technical report No. 16, April 1-June 30, 1980

Description: The High Temperature Heat Flux Test Unit was put into operation during July 1979. Tests using both propane and coal fuels have been completed. Test results are summarized in this report. The object of the Economic and Applications Task of the Program is to evaluate the economic and logistic factors that might influence the schedule and circumstances under which coal fired Atmospheric Fluidized Bed Combustion (AFBC) technology might be applied to petroleum and petrochemical plant process heaters. The results of these studies indicate that the potential for near term application of AFBC technology to refinery crude heaters is relatively low. A possible alternative application of FBC heaters in the Exxon Donor Solvent Process for the liquefaction of coal has been identified. In this alternative an FBC heater would be used to burn the heavy vacuum tower bottoms. A preliminary design of such a heater has been completed and released to the Exxon Synfuels Division for further evaluation. The final task of the program will be to prepare a design specification for a hypothetical commercial sized process heater from which all interested parties can make a definitive evaluation of the technical and commercial prospects of the technology. This design work is now underway.
Date: January 1, 1980
Partner: UNT Libraries Government Documents Department

Measuring and modeling solids movement in a large, cold fluidized bed test facility. Third quarterly report, April 1-June 30, 1980

Description: A considerable fraction of the apparent gas dispersion coefficient of a fluidized bed is due to a non-dispersive meander of the bed gas as it travels up through the bed. The experimental results indicate that a dispersion coefficient which is obtained by measuring the time average concentration at some location in the bed and then comparing the concentration to the tracer inlet rate will overestimate the real turbulent/molecular dispersion coefficient by as much as 60 to 70%. The meander coefficient was observed to vary from 0.0005 ft/sup 2//sec at a superficial velocity of 1.5 ft/sec (about 1.9 u/sub 0//u/sub mf/) to about 0.068 ft/sup 2//sec at an air velocity of 6.0 ft/sec. The corresponding range in the turbulent/molecular dispersion coefficient was 0.004 ft/sup 2//sec to 0.10 ft/sup 2//sec. The meander coefficient shows a continued increase with air velocity whereas the turbulent/molecular coefficient was very close to the same value for the two highest velocities. There is some weak evidence of anisotropy in the meander dispersion coefficient. The turbulent/molecular coefficient seems to be independent of location.
Date: June 1, 1980
Creator: Fitzgerald, T. J.; Mrazek, R. V. & Crane, S. D.
Partner: UNT Libraries Government Documents Department

Development of potential uses for the residue from fluidized bed combustion processes. Quarterly technical progress report, June-August 1980

Description: The following conclusions are recorded: The road base mixes in which quartz silica was substituted for the pulverized coal fly ash gave compressive strengths similar to those using the pulverized coal fly ash. The compressive strengths of road base mixes using recently produced AFB residue were of the same order of magnitude as those obtained in 1977, although the data covers a broad range of test results. Briquettes, produced from a number of trial mixes, show promise as a synthetic aggregate. Expansive grout mixes of slurry consistency achieve satisfactory compressive strengths in seven days. Sections of the test strips in Canton, Ohio show minimal expansion.
Date: January 1, 1980
Creator: Minnick, L.J.
Partner: UNT Libraries Government Documents Department

Development of regenerable sorbents for fluidized bed combustion. Quarterly progress report No. 1, September-December 31, 1979

Description: In the initial work on the current program, equipment employed in the original pioneering study, including a thermogravimetric analyzer, an associated gas-mixing panel, and sorbent pellet preparation and conditioning hardware, was accumulated, tested for operability, refurbished, reinspected and recalibrated for future use. Specifications were prepared for the fabrication of a laboratory-scale hot fluidized bed test unit, and a design for this system was completed by our Mechanical Division. As a means to reinitiate the laboratory program and to test our equipment, new formulations incorporating the calcium aluminate cements (CAC) and barium titanate (BaTiO/sub 3/) materials, which were found to be the most promising sorbent candidates in the original study, were prepared and tested. Titanium dioxide, when incorporated into calcium aluminate cement formulations, produced an improvement in SO/sub 2/ absorption performance and, up to a level of about 5 weight percent, did not degrade crush strengths appreciably. Incorporation of carbon black and/or flyash into TiO/sub 2/-containing CAC formulations produced additional absorption improvement, but significantly reduced sorbent crush strengths. Several promising leads were pursued in the reformulation of barium titanate compositions. But it is apparent that this line of research must be considerably extended to achieve improvements of the type desired.
Date: January 1, 1979
Creator: Kalfadelis, C D & Gaydos, T
Partner: UNT Libraries Government Documents Department

Revised users manual, Pulverized Coal Gasification or Combustion: 2-dimensional (87-PCGC-2): Final report, Volume 2. [87-PCGC-2]

Description: A two-dimensional, steady-state model for describing a variety of reactive and non-reactive flows, including pulverized coal combustion and gasification, is presented. Recent code revisions and additions are described. The model, referred to as 87-PCGC-2, is applicable to cylindrical axi-symmetric systems. Turbulence is accounted for in both the fluid mechanics equations and the combustion scheme. Radiation from gases, walls, and particles is taken into account using either a flux method or discrete ordinates method. The particle phase is modeled in a Lagrangian framework, such that mean paths of particle groups are followed. Several multi-step coal devolatilization schemes are included along with a heterogeneous reaction scheme that allows for both diffusion and chemical reaction. Major gas-phase reactions are modeled assuming local instantaneous equilibrium, and thus the reaction rates are limited by the turbulent rate mixing. A NO/sub x/ finite rate chemistry submodel is included which integrates chemical kinetics and the statistics of the turbulence. The gas phase is described by elliptic partial differential equations that are solved by an iterative line-by-line technique. Under-relaxation is used to achieve numerical stability. The generalized nature of the model allows for calculation of isothermal fluid mechanicsgaseous combustion, droplet combustion, particulate combustion and various mixtures of the above, including combustion of coal-water and coal-oil slurries. Both combustion and gasification environments are permissible. User information and theory are presented, along with sample problems. 106 refs.
Date: December 1, 1987
Creator: Smith, P.J.; Smoot, L.D. & Brewster, B.S.
Partner: UNT Libraries Government Documents Department

(Pulsed atmospheric fluidized bed combustion (PAFBC))

Description: This first Quarterly Technical Progress Report presents the results of work accomplished during the period April 19 through July 24,1988. The overall objective of the program is the development of a pulsed atmospheric fluidized-bed combustion (PAFBC) technology to burn coal and to provide heat and steam to commercial, institutional, and small industrial applications at a reasonable price in an environmentally acceptable manner. the program scope consisted of two tasks; the first was to establish preliminary feasibility by the use of theoretical and state-of-the-art information. This task was completed during the first quarter of the contract period and a topical report entitled, Pulsed Atmospheric Fluidized Bed combustion (PAFBC) - Preliminary Feasibility Study'' was prepared as a decision point to proceed'' deliverable in accordance with the terms of the contract. This first quarterly progress report therefore covers the contract activities subsequent to the approval of the feasibility study and the decision to proceed with the Task 2 effort. As the initial quarterly technical progress report, this document includes a subsection on background which will be omitted in subsequent reports. All effort during this period was devoted to the design and analysis of the PAFBC. Design drawings were prepared and fabrication and procurement initiated. Quotations were evaluated and a fabrication contract awarded. A site adjacent to the MTCI building was chosen for the installation of the PAFBC. Some ancillary components were purchased, renovated, and tested. Some delays in delivery of components have resulted in some schedule delay. It is anticipated that the program pace will accelerate as soon as parts are received and installation and assembly are initiated. 10 figs.,1 tab.
Date: October 1, 1988
Partner: UNT Libraries Government Documents Department

(Pulsed atmospheric fluidized bed combustion (PAFBC)). [Comparing PAFBC vs. AFBC]

Description: The fourth Quarterly Technical Progress Report presents the results of work accomplished during the period February 6 through April 30, 1989. the overall objective of the program is the development of a pulsed atmospheric, fluidized bed combustion (PAFBC) technology to burn coal and to provide heat and steam to commercial, institutional, and small industrial applications at a reasonable price in an environmentally acceptable manner. During this past quarter, a baseline for comparing PAFBC vs. AFBC performance was established and the initial series of PAFBC coal-fired combustion tests was completed. The AFBC baseline was representative of bubbling bed units with the exception of emissions which were somewhat higher and attributable to the size constraints of the AFBC unit. However, it still provided a valid baseline for referencing and optimizing PAFBC performance. Initial coal combustion tests in the pulsed fluid-bed verified enhanced performance in comparison to the non-pulsed beds, providing reduced NO{sub x}, CO, and SO{sub 2} emissions as well as higher steam generation rates and considerably lower entrainment losses. 9 figs., 4 tabs.
Date: May 1, 1989
Partner: UNT Libraries Government Documents Department

Pulse atmospheric fluidized bed combustion

Description: The overall objective of the program is the development of a pulsed atmospheric fluidized-bed combustion (PAFBC) technology to burn coal and to provide heat and steam to commercial, institutional, and small industrial applications at a reasonable price in an environmentally acceptable manner. During this reporting period, a total of eight shakedown and debugging coal combustion tests were performed in the AFBC. A start-up procedure was established, system improvements implemented, and preliminary material and heat balances made based on these tests. The pulse combustor for the AFBC system was fabricated and installed and a series of tests was conducted on the system. 17 figs., 5 tabs.
Date: March 1, 1989
Partner: UNT Libraries Government Documents Department

(Pulsed atmospheric fluidized-bed combustion). [Installation of the pulsed atmospheric fluidized-bed combustion components]

Description: This second Quarterly Technical Progress Report presents the results of work accomplished during the period July 25 through October 30, 1988. The overall objective of the program is the development of a pulsed atmospheric fluidized-bed combustion (PAFBC) technology to burn coal and to provide heat and steam to commercial, institutional, and small industrial applications at a reasonable price in environmentally acceptable manner. Progress during this period accelerated rapidly. The site for the installation of the PAFBC was completed. All of the system components, including the fabrication of the furnace, were also completed. Additional component testing and inspection was also completed. By the end of this period the AFBC was completely assembled and installed at the site adjacent to the MTCI facility and shakedown tests were initiated. 20 figs., 2 tabs.
Date: October 1, 1988
Partner: UNT Libraries Government Documents Department

Superclean coal-water slurry combustion testing in an oil-fired boiler

Description: The Pennsylvania State University is conducting a superclean coal-water slurry (SCCWS) program for the United States Department of Energy (DOE) and the Commonwealth of Pennsylvania with the objective of determining the capability of effectively firing SCCWS in an industrial boiler designed for oil. Penn State has entered into a cooperative agreement with DOE to determine if SCCWS (a fuel containing coal with less than 3.0 wt.% ash and 0.9 wt.% sulfur) can effectively be burned in an oil-designed industrial boiler without adverse impact on boiler rating, maintainability, reliability, and availability. The project will provide information on the design of new systems specifically configured to fire these clean coal-based fuels.
Date: May 29, 1992
Creator: Miller, B.G.; Poe, R.L.; Morrison, J.L.; Xie, Jianyang; Walsh, P.M.; Schobert, H.H. et al.
Partner: UNT Libraries Government Documents Department

Mechanics/heat-transfer relation for particulate materials. [Measure of particle pressure generated in a bed of FCC catalyst that is undergoing particulate fluidization]

Description: The major emphasis this quarter has been in two areas. The first is to continue working the bugs out of the new particle pressure transducer. The second was to try and measure the particle pressures generated in a bed of FCC catalyst that is undergoing particulate fluidization. The results indicate that the stabilization of fluidized beds in that regime cannot be explained in terms of particle pressure generation. Instead, consistent with other recent observations,the observations can be explained by a material is that not completely fluidized but, instead, retains much of the properties of a solid and, in particular, can transmit particle pressure like a solid. 2 figs.
Date: July 1, 1991
Creator: Campbell, C.S.
Partner: UNT Libraries Government Documents Department

Impact of increased coal consumption in the Pacific Northwest

Description: The objectives of the National Coal Utilization Assessment are: Identification of the environmental, health and socioeconomic impacts to be expected from the increased use of coal; investigation of mitigation strategies that might be used to manage these impacts; and establishment of working relationships with state and regional agencies and utilities. A number of energy issues were identified in the course of the study. Probably the most significant issues in this region are the siting of coal-fired power plants and the tradeoff in water allocation between energy and agriculture. Choices of coal-fired generation sites and water use determine the level of impacts to air, water, land, terrestrial and aquatic ecosystems, and human health and socioeconomics. Air quality impacts were studied by incorporating current and projected emission inventories into both short-range and long-range air quality diffusion models. Results indicate that annual average ambient air quality standards will not be exceeded at any of the sites. Surface water supplies are more than adequate to meet the needs of new coal-fired generating plants located in the Columbia or Snake River; however, future conflicts could arise with agriculture over allocation of water rights. Water quality impacts would be minimal, even in the delicate estuarine and coastal sites, under the assumed control and cooling designs. Terrestrial ecosystems do not appear to be threatened as long as specific sites are selected to avoid identified areas of ''critical'' habitat. Impacts on aquatic biota and habitats seem manageable as long as existing regulations are met. Several rare or endangered species are identified. A computer model was used to facilitate the analysis of socioeconomic impacts to be expected from the addition of coal-fired generating capacity at the candidate sites. A number of issues which are still largely unresolved and deserve further attention are mentioned.
Date: March 1, 1978
Creator: Burnham, J.B. (comp.)
Partner: UNT Libraries Government Documents Department

Tennessee Valley Authority atmospheric fluidized-bed combustor simulation interim annual report, January 1-December 31, 1979

Description: This report contains a detailed description of the work performed during 1979 for the Tennessee Valley Authority in support of the TVA Fluidized-Bed Combustor (FBC) Demonstration Plant Program. The work was carried out under task 4, modeling and simulation of atmospheric fluidized-bed combustor (AFBC) systems. The overall objective of this task is to develop a steady-state mathematical model with the capability of predicting trends in bed performance under various feed and operating conditions. As part of this effort, three predictive subprograms (subcodes) were developed during 1979: (1) bubble-growth subcode, (2) sorbent-coal ash elutriation and attrition subcode, and (3) coal combustion subcode. These codes, which are currently being tested with experimental data, are capable of predicting how some of the important operating variables in the AFBC affect its performance. After testing against field data, these subcodes will be incorporated into an overall AFBC system code, which was developed earlier at ORNL for analysis of the Department of Energy (DOE) Component Test and Integration Unit (CTIU) at Morgantown, West Virginia. In addition to these predictive subcodes, the overall system code previously developed for the CTIU is described. The material balance is closed, based on vendor-supplied data. This balance is then used to predict the heat transfer characteristics of the surfaces (submerged and freeboard) in the AFBC. Existing correlations for heat transfer in AFBC are used in the code along with thermophysical properties of the various streams.
Date: October 1, 1980
Creator: Wells, J.W. & Krishnan, R.P.
Partner: UNT Libraries Government Documents Department

The use of synchrotron radiation for the analysis of coal combustion products

Description: An understanding of the chemical composition of such slags under boiler operating conditions and as function of the mineral composition of various coals is the ultimate goal of this program. The experiment involves scanning through the K- or L-shell absorption edge of the element in question. The structure of the absorption edge, consisting of transitions to unoccupied molecular levels, can be compared to those of model compounds for identification. The relative position of the absorption edge can yield information regarding the oxidation state of the element. This portion is the X-ray Absorption Near Edge Structure (XANES) portion of the spectrum. The Extended X-ray Absorption Fine Structure (EXFAS) region, extending from about 60 eV above the absorption edge, represents scattering from neighboring constituents and can be used to determine the coordination number of coordination distance of a specific element from its neighboring atoms. The best source of excitation energy for these experiments is an electron storage ring emitting synchrotron radiation (SR). The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory is a 2.5 GeV storage ring and emits a continuous spectrum of x rays to an energy of about 30 keV. Beam line X-19A is dedicated to XANES and EXAFS and is being adapted to the performance of this investigation.
Date: May 1, 1992
Creator: Manowitz, B. & Gordon, B.
Partner: UNT Libraries Government Documents Department

Condensing economizers for small coal-fired equipment

Description: Condensing economizers can be used to increase the thermal efficiency of boilers and furnaces. This study focuses on evaluating indirect contact economizers as applied to heating equipment burning coal-water mixtures although the results can be extended to other fuels. In addition to dry gas sensible heat, latent heat is recovered from flue gas water vapor, improving system efficiency markedly. In addition to improving thermal efficiency, condensing economizers can also capture particulates. In tests to date up to 89% removal has been measured. The primary objectives of this project are to evaluate the most important mechanisms involved in particle capture and to enhance capture in practical systems. The intent of the work is to contribute to the ongoing program at the Department of Energy/Pittsburgh Energy Technology Center in the development of coal-fired combustion equipment. These results are expected to be most applicable to smaller scale equipment, where the low temperature heat from the economizer can be used. The approach involves determining thermal efficiency improvement and particulate removal efficiency (experimental), and developing models capable of predicting system performance under varied operating conditions (theoretical). Gas temperature and condensation profiles through the economizers have been predicted and overall predicted performance are consistent with test results. Mechanisms for particle removal are discussed in this paper and predicted removal efficiencies as a function of particle diameter are presented. 4 refs.
Date: May 1, 1992
Creator: Litzke, Wai Lin; Butcher, T.A. (Brookhaven National Lab., Upton, NY (United States)) & Park, N.A. (Stony Brook Scientific, Ltd., Morristown, PA (United States))
Partner: UNT Libraries Government Documents Department