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Stability of flows in fluidized beds

Description: We study the linearized stability of the state of uniform fluidization, within the context of the theory of mixtures. The mixture is assumed to be made up of a classical linearly viscous fluid mixed with solid particles. In marked departure from most of the previous studies, we model the solid as a granular material and assume a constitutive relation that stems from classical motions in continuum mechanics. The linearized stability analysis of the state of uniform fluidization, in general, leads to an eighth order equation for the characteristic whose root implies instability, when positive. We find that the characteristic equation can be factored and one of the factors is precisely the equation that governs the stability when we use a simplified analysis akin to that of the earlier study of Anderson and Jackson.
Date: April 1, 1993
Partner: UNT Libraries Government Documents Department

Carbon attrition during the fluidized combustion of coal. Quarterly technical progress report, 1 December 1983-29 February 1984

Description: Batch fluidized bed combustion of 5 mm particles of petroleum coke has been carried out in the 40 mm ID combustors previously described (DOE Reports No. DOE/PC40796-1 and 2), to investigate the generation of fines due to the abrasion of bed solids on the surface of burning particles. The modification produced in the texture of the cortical region of coke particles by combustion have been examined under an optical microscope and related to the activation of the surface in respect to attrition. A descriptive model of combustion assisted attrition of particles of petroleum coke burning in a fluidized bed has been proposed. 17 references, 8 figures, 1 table.
Date: January 1, 1984
Creator: Massimilla, L.; Chirone, R. & D'Amore, M.
Partner: UNT Libraries Government Documents Department

Measuring and modeling solids movement in a large, cold fluidized bed test facility. Fourth quarterly report, July 1, 1980-September 30, 1980

Description: The principle of operation of the magnetic-particle, mass-flow measuring device was described in the first quarterly report. In addition, the results of a few preliminary tests which were carried out to show the feasibility of using this device were described in the third quarterly report. It was noted that the output signal from the device is proportional to velocity and that saturation of the material in the vicinity of the read coil had not yet been achieved. Thus, efforts during this quarter were concentrated upon two objectives - achieving saturation of the magnetic material in the vicinity of the road coil and establishing calibration procedures to be used with the device installed in a fluidized bed.
Date: September 1, 1980
Creator: Fitzgerald, T. J.; Mrazek, R. V. & Crane, S. D.
Partner: UNT Libraries Government Documents Department

Kinetic behavior of solid particles in fluidized beds

Description: The overall objectives of this project are to develop experimental techniques for measuring the forces of fluidized particles, and to predict the solid-gas performance in fluidized beds by using data analysis system, and by elucidating the intrinsic mechanism of erosion and attrition phenomena in fluidized beds. The reduction of erosion and attrition rates is one of the critical engineering problems for the design and operation of fluidized bed combustors. Specifically, the objectives are to: (1) develop the experimental techniques to measure the forces of solid particles prevailing in fluidized beds: (2) measure and characterize the forces of solid particles in various types of fluidized beds with various configurations (conventional and spouted fluidized beds) and with different scales (10, 20, and 30cm) under various fluidization conditions (particle size, bed aspect ratio and gas velocity); (3) find and verify the mechanism of erosion rates of in-bed tubes and attrition rates of fluidized particles by forces of solid particles in fluidized beds. We developed three different kinds of measurement methods, i.e., fracture sensitive sensor, piezoelectric sensor and gas pressure fluctuation method. By using these methods the exact forces of solid particles, including the transient corporate in fluidized beds, were systematically measured. Simultaneously, the erosion rates of in-bed tubes and attrition rates of fluidized particles were measured. 69 figs., 9 tabs.
Date: June 1, 1990
Creator: Kono, H.O.
Partner: UNT Libraries Government Documents Department

Development of algorithms for capacitance imaging techniques for fluidized bed flow fields

Description: The objective of this research is to provide support for the instrumentation concept of a High Resolution Capacitance Imaging System (HRCIS). The work involves the development and evaluation of the mathematical theory and associated models and algorithms which reduce the electronic measurements to valid physical characterizations. The research and development require the investigation of techniques to solve large systems of equations based on capacitance measurements for various electrode configurations in order to estimate densities of materials in a cross-section of a fluidized bed. Capacitance measurements are made for 400 connections of the 32-electrode system; 400 corresponding electric-field curves are constructed by solving a second order partial differential equation. These curves are used to partition the circular disk into 193 regions called pixels, and the density of material in each pixel is to be estimated. Two methods of approximating densities have been developed and consideration of a third method has been initiated. One method (Method 1) is based on products of displacement currents for intersecting electric-field curves on a cross section. For each pixel one point of intersection is chosen, and the product of the capacitance measurements is found. Both the product and the square-root-of-product seem to yield good relative distribution of densities.
Date: January 1, 1991
Creator: Loudin, W.J.
Partner: UNT Libraries Government Documents Department

Development of an advanced high efficiency coal combustor for boiler retrofit

Description: During the quarter from October 1986 to January 1987 the following technical progress was made: (1) Initiated a literature study focusing on optimized burner aerodynamics and design methodologies for high efficiency swirl generation devices, (2) Completed design of Swirler Test Facility (STF) to be used for comparative swirler evaluations, and (3) Initiated facility preparation at MIT for thermal atomization studies and high shear viscosity measurements.
Date: May 6, 1987
Creator: Rini, M.J.; LaFlesh, R.C. (Combustion Engineering, Inc., Windsor, CT (United States)); Beer, J.M.; Togan, M.A.; Yu, T.U. (Massachusetts Inst. of Tech., Cambridge, MA (United States)) & McGowan, J.G. (Univ. of Massachusetts, MA (United States))
Partner: UNT Libraries Government Documents Department

Development of a retrofit coal combustor for industrial applications, (Phase 2)

Description: The objective of Phase I of the program for the development of a retrofit pulse coal combustor for industrial applications was to design, fabricate, test and evaluate advanced chamber designs at the laboratory-scale utilizing several fuels (Task 1). The activities were structured to provide design criteria for scaling up to the pilot-scale level for the demonstration of a pulse combustor fired with coal-water mixtures for industrial boiler and process heater retrofit applications. The design data and information acquired during Task 1 of the initial phase was to develop scale-up design criteria for scaling the laboratory-scale design to pilot-scale including interface requirements for the field demonstration. The scale-up pilot unit design was to be sufficiently developed to allow fabrication of the unit for testing in the existing test facility upon DOE exercising its option for the follow-on activities of this program. These follow-on activities (Phase II) included the fabrication, test, and engineering evaluation of the pilot-scale combustor as well as technical and laboratory test support activities for reducing the technical risks and costs of development at the pilot-scale. Based on the information, test, data and technical support activities, a retrofit combustor system was to be designed for field demonstration. An additional effort was added to the contract by modification A005. This modification added a Phase IA in place of the original Task 2 of Phase I activity. This interim phase consisted of three technical tasks described in previous quarterly reports. Phase II was initiated in April 1989.
Date: July 1, 1989
Partner: UNT Libraries Government Documents Department

Digital image processing applications in the ignition and combustion of char/coal particles

Description: Digital image processing, is employed in this remarch study in order to visually investigate the ignition and combustion characteristics of isolated char/coal particles as well as the effect of interactivecombustion in two-particle char/coal arrays. Preliminary experiments are conducted on miniature isolated candles as well as two-candle arrays.
Date: December 1, 1992
Creator: Annamalai, K.; Kharbat, E. & Goplakrishnan, C.
Partner: UNT Libraries Government Documents Department

TRW Advanced Slagging Coal Combustor Utility Demonstration

Description: The TRW Advanced Slagging Coal Combustor Demonstration Project consists of retrofitting Orange and Rockland (O R) Utility Corporation's Lovett Plant Unit No. 3 with four (4) slagging combustors which will allow the gas/ou desip unit to fire 2.5 sulfur coal. The slogging combustor process will provide NO[sub x] and SO[sub x] emissions that meet NSPS and New York State Envirommental Standards. TRW-CBU scope of work includes the engineering, design and supply of the slogging combustors, coal and limestone feed systems and a control system for these components. During this report period, the design activities for all systems progressed to permit the release of specifications and requests for proposals. Award of contracts for long-delivery items and major equipment are being placed to meet the revised program schedule.
Date: January 1, 1989
Partner: UNT Libraries Government Documents Department

Kinetic behavior of solid particles in fluidized beds: Annual report

Description: This report summarizes technical accomplishments for the first year in a 3-year contract project for the Morgantown Energy Technology Center (METC) of the US Department of Energy (DOE) under contract number AC21-86MC23249. The objectives of the project are (1) to develop experimental techniques for measuring the forces of fluidized particles, and (2) to predict solid particle performance in fluidized beds using data analysis and mathematical modeling. During the first year, the fracture-sensitive tracer-particle method was developed and applied to investigate the effects of fluidized particle size, superficial gas velocity, bed height, bed diameter, and bed configuration on the kinetic behavior of solid particles in fluidized beds. Quantitative data and comprehensive information were obtained. A piezoresistive strain-gauge sensor and a PC data-acquisition system were also developed; these are being used to measure the force distribution in fluidized beds. The pressure fluctuation method will also be investigated in the near future. 12 refs., 24 figs., 2 tabs.
Date: October 1, 1987
Creator: Kono, H.O. & Huang, C.C.
Partner: UNT Libraries Government Documents Department

Pulverized fuel combustion: modeling and scaleup methodologies. First quarterly report, September 19-December 31, 1980

Description: This document is the first quarterly progress report on the effort to develop an understanding of the stability and carbon carryover characteristics of pulverized fuel combustors. This work is to be accomplished by improving and extending a model developed for entrained flow coal gasifier analysis by including a better description of the finite rate coal pyrolysis, pyrolysis product chemistry, char reactions, particle-particle interactions, radiative transport and recirculation/mixing. The data to be analyzed with the model will include data from simple (cylindrical symmetry) geometry combustors with premixed and mixing reactants, swirl and recirculation. The analysis of these data with the model should lead to an understanding of the effects of fuel type, swirl, recirculation, O/F ratio and mixing rate on the location (stability) of the flame and the carbon carryover from the combustor.
Date: January 1, 1981
Creator: Lewis, Paul F.; Wolf, Thomas L. & Gelb, Alan
Partner: UNT Libraries Government Documents Department

Roles of additives and surface control in slurry atomization

Description: This project studies the rheology and airblast atomization of micronized coal slurries. Its major objectives are (1) to promote further understanding of the mechanisms and the roles of additives in airblast atomization of coal water slurry (CWS), and (2) to investigate the impacts of coal particle surface properties and interparticle forces on CWS rheology. We have found that the flow behavior index (n) of a suspension (or slurry) is determined by the relative importance of the interparticle van der Waals attraction and the interparticle electrostatic repulsion. The interparticle attraction, measured by the Hamaker constant scaled to the thermal energy at 25[degrees]C (A/kT), causes particle aggregation, which breaks down at high shear rates, and thus leads to slurry pseudoplastic behavior (n< 1). At a constant particle volume fraction and surface charge density (qualitatively measured by the zeta potential in deionized water), n decreases linearly as A/kT increases. The relative viscosity of the pseudoplastic suspension with respect to that of the suspending liquid is found to be independent of particle density and correlate well with the particle Peclet number which equals the particle diffusional relaxation time multiplied by shear rate. Specifically, the relative viscosities of the pseudoplastic glycerol/water coal slurry and the ethylene glycol/glycerol sand slurry, at same volume fractions as well as similar particle size distributions and liquid viscosities, as functions of the particle Peclet number fall along the same line.
Date: January 1, 1992
Creator: Tsai, S.C.
Partner: UNT Libraries Government Documents Department

Roles of additives and surface control in slurry atomization

Description: This quarterly report describes a quantitative correlation between the flow behavior index of a micronized coal slurry and the interparticular van der Waals attraction force as measured by the Hamaker constant. Preliminary results on the effects of interparticular electrostatic repulsion and the liquid viscosity on both the flow behavior and the relative viscosity are also presented.
Date: March 1, 1990
Creator: Tsai, S.C.
Partner: UNT Libraries Government Documents Department

Tidd PFBC Demonstration Project

Description: This is the 21st Technical Progress Report submitted to the Department of energy in connection with the Cooperative Agreement between the DOE and the Ohio Power Company for the Tidd PFBC Demonstration Plant. This report covers the period from April 1, 1992--June 30, 1992.
Date: July 1, 1992
Partner: UNT Libraries Government Documents Department

TIDD PFBC Demonstration Project: Third quarterly technical progress report 1992, CY 1992

Description: This is the 22nd Technical Progress Report submitted to the Department of Energy in connection with the Cooperative Agreement between the DOE and the Ohio Power Company for the Tidd PFBC Demonstration Plant. This report covers the period from July 1, 1992 to September 30, 1992. The unit was operated for a total of 903 hours (including gas turbine air prewarming). There were 9 gas turbine starts, 11 preheating starts, and 8 operating periods with coal fire. The peak gross output of 59 MWH was achieved for the period of 1600 to 1700 hours on September 23, 1992. The longest coal fire was 422 hourb beginning at 1349 hours on August 9, 1992. Total gross generation was 32,418 MWH, and coal consumption was 15,846 tons. Testing was completed on the gas turbine blade resonance frequency problem. The report showed that a resonant frequency problem existing at high LPT speeds and at a mostly closed guide vane position. An operating curve was developed by ABBC to avoid the points of blade resonance. Monitoring of solid, liquid and gaseous waste streams, as detailed in the operations phase monitoring requirements in the EMP, were performed throughout the quarter.
Date: October 1, 1992
Partner: UNT Libraries Government Documents Department

Synthesis of a naphthalene-hydroxynaphthalene polymer model compound

Description: The objective of this contract is the synthesis of a new naphthalene-hydroxynaphthalene polymer model compound for coal combustion studies. This effort also requires the development of a synthetic procedure for this compound since it has not been reported before. We can only report that we are still unable to provide the target polymer or even any of the key intermediates leading to this target Dr. Rao has been informed of our progress (or lack of progress), and he has suggested that we begin to design other alternative compounds which contain the functionalities required by the target compound. In response to this suggestion, we have quickly designed the potential targets shown in Scheme VIL We are currently evaluating the schemes further and we will continue designing routes to the other analogous compounds.
Date: April 15, 1991
Creator: Kwong, C.D.
Partner: UNT Libraries Government Documents Department

Combustion of pulverized coal in counter-current flow

Description: The project objective is to develop and investigate pulverized coal combustors operating in counter-current flow. In the first year of the project our activity was focused on: (a) design, calculation and fabrication of a prototype of the combustor for atmospheric pressure operation, (b) purchase and fabrication of the measuring instruments and preparation of the facilities for experiments, (c) performing the experiments with the combustor firing bituminous coals (including a coal delivered from the USA), and (d) theoretical - predictive work.
Date: January 1, 1992
Creator: Timant, Y.M. & Goldman, Y. (Technion-Israel Inst. of Tech., Haifa (Israel). Faculty of Aeronautical Engineering)
Partner: UNT Libraries Government Documents Department

A coal-fired combustion system for industrial process heating applications

Description: This advanced combustion system research program is for the development of innovative coal-fired process heaters which can be used for high temperature melting, smelting and waste vitrification processes. The process heater concepts to be developed are based on advanced glass melting and ore smelting furnaces developed and patented by Vortec Corporation. The process heater systems to be developed have multiple use applications; however, the Phase III research effort is being focused on the development of a process heater system to be used for producing value added vitrified glass products from boiler/incinerator ashesand industrial wastes. ne primary objective of the Phase III project is to develop and integrate all the system components, from fuel through total system controls, and then test the complete system in order toevaluate its potential marketability. During the current reporting period, three preliminary coal-fired tests were successfully completed. These tests used industrial boiler flyash, sewer sludge ash, and waste glass collet as feedstocks. The coal-fired ash vitrification tests are considered near term potential commercial applications of the CMS technology. The waste glass cullet provided necessary dam on the effect of coal firing with respect to vitrified product oxidation state. Engineering and design activities in support of the Phase III proof of concept are continuing, and modifications to the existing test system configuration to allow performance of the proof-of-concept tests are continuing. The economic evaluation of commercial scale CMS processes is continuing. Preliminary designs for 15, 25, 100 and 400 ton/day systems are in progress. This dam will serve as input data to the life cycle cost analysis which will be-an integral part of the CMS commercialization plan.
Date: October 30, 1992
Partner: UNT Libraries Government Documents Department

Collaborative research on fluidization employing computer-aided particle tracking

Description: This report covers the fourth quarter of the subject contract. The primary objective of the first year is construction of a portable computer-aided particle tracking apparatus to be used eventually at the Morgantown Energy Technology Center (METC). Third quarter effort was devoted to software development and system interconnection. These efforts continue in this quarter with hardware interface has enabled us to verify that that detectors, scalers, and discriminators are all working properly. Software debugging is now proceeding. Progress has also been made in the fabrication of the tracer particle to match the bed particles to be used at METC.
Date: January 1, 1989
Creator: Chen, M.M.
Partner: UNT Libraries Government Documents Department

Combustion of dense streams of coal particles

Description: Ignition of the high volatile isolated coal particles in vitiated environment seems to occur heterogeneously at the leading edge of the particle. Volatiles are observed to be ejected upward as jets in the direction of the convective flow but only after heterogeneous ignition. The volatiles burn in the gas phase homogeneously and form a wake flame; a black inner zone (unburned volatile) is formed (see Fig.A.3 for many common characteristics of isolated flames).Intermittent volatile ignition and combustion are observed to occur during the combustion process for a few of the isolated particle combustion experiments on high volatile non-swelling coal. The medium volatile coal particles ignite faster than the high volatile coal; but the intermittent ignition is not observed. The low volatile isolated coal particles combust in shorter time. The isolated char particles ignite at the surface of the particle heterogeneously with little volatile ejected, yet are not sufficient to form a volatile flame, resulting in a subsequent heterogeneous combustion. A group flame is formed for the two-particle arrays at closer interparticle spacing (Fig.A.4). Also, intermittent ignition does not occur for the high volatile particles when the two particles are at farther distances which suggests that radiation interaction between the particles might be occurring. However this conclusion is purely speculative. The char arrays experience heterogeneous ignition at the leading edge; combustion proceeds heterogeneously.
Date: January 1, 1992
Creator: Annamalai, K.
Partner: UNT Libraries Government Documents Department

Particle pressures in fluidized beds

Description: This is an experimental project to make detailed measurements of the particle pressures generated in fluidized beds. The focus lies in two principle areas: (1) the particle pressure distribution around single bubbles rising in a two-dimensional gas-fluidized bed and (2) the particle pressures measured in liquid-fluidized beds. This first year has largely been to constructing the experiments The design of the particle pressure probe has been improved and tested. A two-dimensional gas-fluidized bed has been constructed in order to measure the particle pressure generated around injected bubbles. The probe is also being adapted to work in a liquid fluidized bed. Finally, a two-dimensional liquid fluidized bed is also under construction. Preliminary measurements show that the majority of the particle pressures are generated in the wake of a bubble. However, the particle pressures generated in the liquid bed appear to be extremely small. Finally, while not directly associated with the particle pressure studies, some NERSC supercomputer time was granted alongside this project. This is being used to make large scale computer simulation of the flow of granular materials in hoppers.
Date: January 1, 1992
Creator: Campbell, C.S.; Rahman, K.; Hu, X.; Jin, C. & Potapov, A.V.
Partner: UNT Libraries Government Documents Department

Research on fundamental aspects of inorganic vapor and particle deposition in coal-fired systems

Description: In September 1990 DOE-PETC initiated at the Yale HTCRE Laboratory a systematic three-year research program directed toward providing engineers with the fundamentally-based design/optimization 'tools' for economically predicting the dynamics of net deposit growth*, and thermophysical properties of the resulting microparticulate deposits in coal-fired systems. In light of the theoretical 'program' based on the notion of self-regulation'' set forth in Rosner and Nagarajan (1987), this Task includes investigation of the effects of particle material properties and possible liquid phases on the capture properties of particulate deposits. For this purpose we exploit dynamical 'many-body' computer simulation techniques. This approach will provide the required parametric dependencies (on such quantities as incident kinetic energy and angle, mechanical and thermophysical properties of the particles,[hor ellipsis]) of a dimensionless ensemble-averaged particle capture fraction, relegating the role of direct laboratory experiment to verifying (or rejecting) some crucial features/consequences of the simulation route followed. Our ultimate goal is recommend 'sticking' and 'erosion' laws of mechanistic origin. The availability of such laws could dramatically increase the reliability of predicted deposition rates of inertially delivered particles, in the simultaneous presence of a condensed liquid phase within the growing particulate, deposit. Equally important, one could also rationally select conditions to avoid. troublesome deposition subject to other operational requirements.
Date: September 1, 1992
Creator: Rosner, D.E.
Partner: UNT Libraries Government Documents Department

Research on fundamental aspects of inorganic vapor and particle deposition in coal-fired systems

Description: Parallel research studies are underway on the following interrelated and fundamental subjects; Geometrical Approach to Determining the Sticking Probability of Particles Impacting on Convex Solid Surfaces; Correlations for High Schmidt Number Particle Deposition From Dilute Flowing Rational Engineering Suspensions; Average Capture Probability of Arriving Particles Which Are Distributed With ResPect to ImPact VelocitY and Incidence Angle (Relative to Deposit Substrate); Experimental and Theoretical Studies of Vapor Infiltration of Non-isothermal Granular Deposits; Effective Area/Volume of Populations of 'MicroPorous' Aerosol Particles (Compact and 'Fractal' Quasispherical Aggregates); Effects of Radiative Heat Transfer on the Coagulation Rates of Combustion-Generated Particles; Structure-Sensitivity of Total Mass Deposition Rates from Combustion Product Streams containing Coagulation-Aged Populations of Aggregated Primary Particles; and Na[sub 2]SO[sub 4] Chemical Vapor Deposition From Chlorine-containing Coal-Derived Gases.
Date: June 1, 1992
Creator: Rosner, D.E.
Partner: UNT Libraries Government Documents Department