Science.gov

Sample records for fluidized-bed column method

  1. Methods of forming a fluidized bed of circulating particles

    DOEpatents

    Marshall, Douglas W.

    2011-05-24

    There is disclosed an apparatus for forming a fluidized bed of circulating particles. In an embodiment, the apparatus includes a bottom portion having a sidewall, the sidewall defining a curvilinear profile, and the bottom portion configured to contain a bed of particles; and a gas inlet configured to produce a column of gas to carry entrained particles therein. There is disclosed a method of forming a fluidized bed of circulating particles. In an embodiment, the method includes positioning particles within a bottom portion having a sidewall, the sidewall defining a curvilinear profile; producing a column of gas directed upwardly through a gas inlet; carrying entrained particles in the column of gas to produce a fountain of particles over the fluidized bed of circulating particles and subside in the particle bed until being directed inwardly into the column of gas within the curvilinear profile.

  2. Fluidized-bed column method for automatic dynamic extraction and determination of trace element bioaccessibility in highly heterogeneous solid wastes.

    PubMed

    Rosende, María; Miró, Manuel; Cerdà, Víctor

    2010-01-18

    Dynamic flow-through extraction/fractionation methods have recently drawn much attention as appealing alternatives to the batchwise steady-state counterparts for the evaluation of environmentally available pools of potentially hazardous trace elements in solid matrices. The most critical weakness of flow-based column approaches lies in the small amount of solid that can be handled, whereby their applicability has been merely limited to date to the extraction of trace elements in highly homogeneous solid substrates; otherwise the representativeness of the test portion might not be assured. To tackle this limitation, we have devised an automated flow-through system incorporating a specially designed extraction column with a large volume capacity, wherein up to 2 g of solid sample could be handled without undue backpressure. The assembled flow setup was exploited for fast screening of potentially hazardous trace elements (namely, Cd, Cr, Cu, Pb, and Zn) in highly inhomogeneous municipal solid waste incineration (MSWI) bottom ashes. The pools of readily mobilizable metal forms were ascertained using the Toxicity Characteristic Leaching Procedure (TCLP) based on the usage of 0.1 mol L(-1) CH(3)COOH as leachant and analysis of extracts by inductively coupled optical emission spectrometry. The application of a two-level full factorial (screening) design revealed that the effect of sample fluidization primarily but other experimental factors such as the solid to liquid ratio and extractant flow rate significantly influenced the leachability of given elements in raw bottom ashes at the 0.05 significance level. The analytical performance of the novel flow-based method capitalized on fluidized-bed extraction was evaluated in terms of accuracy, through the use of mass balance validation, reproducibility and operational time as compared to batchwise extraction and earlier flow injection/sequential injection microcolum-based leaching tests. PMID:20082772

  3. Staged fluidized bed

    DOEpatents

    Mallon, R.G.

    1983-05-13

    The invention relates to oil shale retorting and more particularly to staged fluidized bed oil shale retorting. Method and apparatus are disclosed for narrowing the distribution of residence times of any size particle and equalizing the residence times of large and small particles in fluidized beds. Particles are moved up one fluidized column and down a second fluidized column with the relative heights selected to equalize residence times of large and small particles. Additional pairs of columns are staged to narrow the distribution of residence times and provide complete processing of the material.

  4. Spectral methods applied to fluidized bed combustors. Final report

    SciTech Connect

    Brown, R.C.; Christofides, N.J.; Junk, K.W.; Raines, T.S.; Thiede, T.D.

    1996-08-01

    The objective of this project was to develop methods for characterizing fuels and sorbents from time-series data obtained during transient operation of fluidized bed boilers. These methods aimed at determining time constants for devolatilization and char burnout using carbon dioxide (CO{sub 2}) profiles and from time constants for the calcination and sulfation processes using CO{sub 2} and sulfur dioxide (SO{sub 2}) profiles.

  5. Method for using fast fluidized bed dry bottom coal gasification

    DOEpatents

    Snell, George J.; Kydd, Paul H.

    1983-01-01

    Carbonaceous solid material such as coal is gasified in a fast fluidized bed gasification system utilizing dual fluidized beds of hot char. The coal in particulate form is introduced along with oxygen-containing gas and steam into the fast fluidized bed gasification zone of a gasifier assembly wherein the upward superficial gas velocity exceeds about 5.0 ft/sec and temperature is 1500.degree.-1850.degree. F. The resulting effluent gas and substantial char are passed through a primary cyclone separator, from which char solids are returned to the fluidized bed. Gas from the primary cyclone separator is passed to a secondary cyclone separator, from which remaining fine char solids are returned through an injection nozzle together with additional steam and oxygen-containing gas to an oxidation zone located at the bottom of the gasifier, wherein the upward gas velocity ranges from about 3-15 ft/sec and is maintained at 1600.degree.-200.degree. F. temperature. This gasification arrangement provides for increased utilization of the secondary char material to produce higher overall carbon conversion and product yields in the process.

  6. Method of feeding particulate material to a fluidized bed

    DOEpatents

    Borio, Richard W.; Goodstine, Stephen L.

    1984-01-01

    A centrifugal spreader type feeder that supplies a mixture of particulate limestone and coal to the top of a fluidized bed reactor having a flow of air upward therethrough. Large particles of particulate matter are distributed over the upper surface of the bed to utilize the natural mixing within the bed, while fine particles are adapted to utilize an independent feeder that separates them from the large particles and injects them into the bed.

  7. Fluidized bed and method and system for gas component capture

    DOEpatents

    Krutka, Holly; Wilson, Cody; Starns, Travis

    2016-05-31

    The present disclosure is directed to a process that allows dry sorbents to remove a target constituent, such as carbon dioxide (CO.sub.2), from a gas stream. A staged fluidized bed separator enables gas and sorbent to move in opposite directions. The sorbent is loaded with target constituent in the separator. It is then transferred to a regenerator where the target constituent is stripped. The temperature of the separator and regenerator are controlled. After it is removed from the regenerator, the sorbent is then transferred back to the separator.

  8. A 2.5D Computational Method to Simulate Cylindrical Fluidized Beds

    SciTech Connect

    Li, Tingwen; Benyahia, Sofiane; Dietiker, Jeff; Musser, Jordan; Sun, Xin

    2015-02-17

    In this paper, the limitations of axisymmetric and Cartesian two-dimensional (2D) simulations of cylindrical gas-solid fluidized beds are discussed. A new method has been proposed to carry out pseudo-two-dimensional (2.5D) simulations of a cylindrical fluidized bed by appropriately combining computational domains of Cartesian 2D and axisymmetric simulations. The proposed method was implemented in the open-source code MFIX and applied to the simulation of a lab-scale bubbling fluidized bed with necessary sensitivity study. After a careful grid study to ensure the numerical results are grid independent, detailed comparisons of the flow hydrodynamics were presented against axisymmetric and Cartesian 2D simulations. Furthermore, the 2.5D simulation results have been compared to the three-dimensional (3D) simulation for evaluation. This new approach yields better agreement with the 3D simulation results than with axisymmetric and Cartesian 2D simulations.

  9. On line diagnostics and self-tuning method for the fluidized bed temperature controller

    NASA Astrophysics Data System (ADS)

    Porzuczek, Jan

    2016-03-01

    The paper presents the method of on-line diagnostics of the bed temperature controller for the fluidized bed boiler. Proposed solution is based on the methods of statistical process control. Detected decrease of the bed temperature control quality is used to activate the controller self-tuning procedure. The algorithm that provides optimal tuning of the bed temperature controller is also proposed. The results of experimental verification of the presented method is attached. Experimental studies were carried out using the 2 MW bubbling fluidized bed boiler.

  10. Phase shift method to estimate solids circulation rate in circulating fluidized beds

    SciTech Connect

    Ludlow, James Christopher; Panday, Rupen; Shadle, Lawrence J.

    2013-01-01

    While solids circulation rate is a critical design and control parameter in circulating fluidized bed (CFB) reactor systems, there are no available techniques to measure it directly at conditions of industrial interest. Cold flow tests have been conducted at NETL in an industrial scale CFB unit where the solids flow has been the topic of research in order to develop an independent method which could be applied to CFBs operating under the erosive and corrosive high temperatures and pressures of a coal fired boiler or gasifier. The dynamic responses of the CFB loop to modest modulated aeration flows in the return leg or standpipe were imposed to establish a periodic response in the unit without causing upset in the process performance. The resulting periodic behavior could then be analyzed with a dynamic model and the average solids circulation rate could be established. This method was applied to the CFB unit operated under a wide range of operating conditions including fast fluidization, core annular flow, dilute and dense transport, and dense suspension upflow. In addition, the system was operated in both low and high total solids inventories to explore the influence of inventory limiting cases on the estimated results. The technique was able to estimate the solids circulation rate for all transport circulating fluidized beds when operating above upper transport velocity, U{sub tr2}. For CFB operating in the fast fluidized bed regime (i.e., U{sub g}< U{sub tr2}), the phase shift technique was not successful. The riser pressure drop becomes independent of the solids circulation rate and the mass flow rate out of the riser does not show modulated behavior even when the riser pressure drop does.

  11. METHOD FOR SENSING DEGREE OF FLUIDIZATION IN FLUIDIZED BED

    DOEpatents

    Levey, R.P. Jr.; Fowler, A.H.

    1961-12-12

    A method is given for detecting, indicating, and controlling the degree of fluidization in a fluid-bed reactor into which powdered material is fed. The method comprises admitting of gas into the reactor, inserting a springsupported rod into the powder bed of the reactor, exciting the rod to vibrate at its resonant frequency, deriving a signal responsive to the amplitude of vibi-ation of the rod and spring, the signal being directiy proportional to the rate of flow of the gas through the reactor, displaying the signal to provide an indication of the degree of fluidization within the reactor, and controlling the rate of gas flow into the reactor until said signal stabilizes at a constant value to provide substantially complete fluidization within the reactor. (AEC)

  12. Method of burning sulfur-containing fuels in a fluidized bed boiler

    DOEpatents

    Jones, Brian C.

    1982-01-01

    A method of burning a sulfur-containing fuel in a fluidized bed of sulfur oxide sorbent wherein the overall utilization of sulfur oxide sorbent is increased by comminuting the bed drain solids to a smaller average particle size, preferably on the order of 50 microns, and reinjecting the comminuted bed drain solids into the bed. In comminuting the bed drain solids, particles of spent sulfur sorbent contained therein are fractured thereby exposing unreacted sorbent surface. Upon reinjecting the comminuted bed drain solids into the bed, the newly-exposed unreacted sorbent surface is available for sulfur oxide sorption, thereby increasing overall sorbent utilization.

  13. Apparatus, components and operating methods for circulating fluidized bed transport gasifiers and reactors

    SciTech Connect

    Vimalchand, Pannalal; Liu, Guohai; Peng, Wan Wang

    2015-02-24

    The improvements proposed in this invention provide a reliable apparatus and method to gasify low rank coals in a class of pressurized circulating fluidized bed reactors termed "transport gasifier." The embodiments overcome a number of operability and reliability problems with existing gasifiers. The systems and methods address issues related to distribution of gasification agent without the use of internals, management of heat release to avoid any agglomeration and clinker formation, specific design of bends to withstand the highly erosive environment due to high solid particles circulation rates, design of a standpipe cyclone to withstand high temperature gasification environment, compact design of seal-leg that can handle high mass solids flux, design of nozzles that eliminate plugging, uniform aeration of large diameter Standpipe, oxidant injection at the cyclone exits to effectively modulate gasifier exit temperature and reduction in overall height of the gasifier with a modified non-mechanical valve.

  14. Method and apparatus for improving heat transfer in a fluidized bed

    DOEpatents

    Lessor, Delbert L.; Robertus, Robert J.

    1990-01-01

    An apparatus contains a fluidized bed that includes particles of different triboelectrical types, each particle type acquiring an opposite polarity upon contact. The contact may occur between particles of the two types or between particles of etiher type and structure or fluid present in the apparatus. A fluidizing gas flow is passed through the particles to produce the fluidized bed. Immersed within the bed are electrodes. An alternating EMF source connected to the electrodes applies an alternating electric field across the fluidized bed to cause particles of the first type to move relative to particles of the second type and relative to the gas flow. In a heat exchanger incorporating the apparatus, the electrodes are conduits conveying a fluid to be heated. The two particle types alternately contact each conduit to transfer heat from a hot gas flow to the second fluid within the conduit.

  15. Fluidized-bed sorbents

    SciTech Connect

    Gangwal, S.K.; Gupta, R.P.

    1994-10-01

    The objectives of this project are to identify and demonstrate methods for enhancing long-term chemical reactivity and attrition resistance of zinc oxide-based mixed metal-oxide sorbents for desulfurization of hot coal-derived gases in a high-temperature, high-pressure (HTHP) fluidized-bed reactor. In this program, regenerable ZnO-based mixed metal-oxide sorbents are being developed and tested. These include zinc ferrite, zinc titanate, and Z-SORB sorbents. The Z-SORB sorbent is a proprietary sorbent developed by Phillips Petroleum Company (PPCo).

  16. Development of a new method for improving load turndown in fluidized bed combustors: Final report

    SciTech Connect

    Brown, R.C.

    1988-12-01

    The objective of this research was to investigate a new concept in fluidized bed design that improves load turndown capability. This improvement is accomplished by independently controlling heat transfer and combustion in the combustor. The design consists of two fluidized beds, one central and one annular. The central bed serves as the combustion bed. The annular bed is fluidized separately from the combustion bed and its level of fluidization determine the overall heat transfer rate from the combustion bed to the surrounding water jacket. Early theoretical considerations suggested a load turndown exceeding ten was possible for this design. This research consisted of three major phases: development of a computational model to predict heat transfer in the two-bed combustor, heat transfer measurements in hot-and-cold flow models of the combustor, and combustion tests in an optimally designed combustor. The computation model was useful in selecting the design of the combustor. Annular bed width and particle sizes were chosen with the aid of the model. The heat transfer tests were performed to determine if the existing correlations for fluidized bed heat transfer coefficients were sufficiently accurate for high aspect ratio fluidized beds (such as the annular bed in the combustor). Combustion tests were performed in an optimally designed combustor. Three fuel forms were used: double screened, crushed coal, coal-water-limestone mixtures (CWLM), and coal-limestone briquettes. 18 refs., 30 figs., 8 tabs.

  17. Fluidized bed calciner apparatus

    DOEpatents

    Owen, Thomas J.; Klem, Jr., Michael J.; Cash, Robert J.

    1988-01-01

    An apparatus for remotely calcining a slurry or solution feed stream of toxic or hazardous material, such as ammonium diurante slurry or uranyl nitrate solution, is disclosed. The calcining apparatus includes a vertical substantially cylindrical inner shell disposed in a vertical substantially cylindrical outer shell, in which inner shell is disposed a fluidized bed comprising the feed stream material to be calcined and spherical beads to aid in heat transfer. Extending through the outer and inner shells is a feed nozzle for delivering feed material or a cleaning chemical to the beads. Disposed in and extending across the lower portion of the inner shell and upstream of the fluidized bed is a support member for supporting the fluidized bed, the support member having uniform slots for directing uniform gas flow to the fluidized bed from a fluidizing gas orifice disposed upstream of the support member. Disposed in the lower portion of the inner shell are a plurality of internal electric resistance heaters for heating the fluidized bed. Disposed circumferentially about the outside length of the inner shell are a plurality of external heaters for heating the inner shell thereby heating the fluidized bed. Further, connected to the internal and external heaters is a means for maintaining the fluidized bed temperature to within plus or minus approximately 25.degree. C. of a predetermined bed temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.

  18. Hybrid fluidized bed combuster

    DOEpatents

    Kantesaria, Prabhudas P.; Matthews, Francis T.

    1982-01-01

    A first atmospheric bubbling fluidized bed furnace is combined with a second turbulent, circulating fluidized bed furnace to produce heat efficiently from crushed solid fuel. The bed of the second furnace receives the smaller sizes of crushed solid fuel, unreacted limestone from the first bed, and elutriated solids extracted from the flu gases of the first bed. The two-stage combustion of crushed solid fuel provides a system with an efficiency greater than available with use of a single furnace of a fluidized bed.

  19. Method of removing sulfur emissions from a fluidized-bed combustion process

    DOEpatents

    Vogel, Gerhard John; Jonke, Albert A.; Snyder, Robert B.

    1978-01-01

    Alkali metal or alkaline earth metal oxides are impregnated within refractory support material such as alumina and introduced into a fluidized-bed process for the combustion of coal. Sulfur dioxide produced during combustion reacts with the metal oxide to form metal sulfates within the porous support material. The support material is removed from the process and the metal sulfate regenerated to metal oxide by chemical reduction. Suitable pore sizes are originally developed within the support material by heat-treating to accommodate both the sulfation and regeneration while still maintaining good particle strength.

  20. Fluidized bed coal desulfurization

    NASA Technical Reports Server (NTRS)

    Ravindram, M.

    1983-01-01

    Laboratory scale experiments were conducted on two high volatile bituminous coals in a bench scale batch fluidized bed reactor. Chemical pretreatment and posttreatment of coals were tried as a means of enhancing desulfurization. Sequential chlorination and dechlorination cum hydrodesulfurization under modest conditions relative to the water slurry process were found to result in substantial sulfur reductions of about 80%. Sulfur forms as well as proximate and ultimate analyses of the processed coals are included. These studies indicate that a fluidized bed reactor process has considerable potential for being developed into a simple and economic process for coal desulfurization.

  1. Pressurized fluidized bed reactor and a method of operating the same

    DOEpatents

    Isaksson, J.

    1996-02-20

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

  2. Pressurized fluidized bed reactor and a method of operating the same

    DOEpatents

    Isaksson, Juhani

    1996-01-01

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

  3. Large-Scale Simulations of Realistic Fluidized Bed Reactors using Novel Numerical Methods

    NASA Astrophysics Data System (ADS)

    Capecelatro, Jesse; Desjardins, Olivier; Pepiot, Perrine; National Renewable Energy Lab Collaboration

    2011-11-01

    Turbulent particle-laden flows in the form of fluidized bed reactors display good mixing properties, low pressure drops, and a fairly uniform temperature distribution. Understanding and predicting the flow dynamics within the reactor is necessary for improving the efficiency, and providing technologies for large-scale industrialization. A numerical strategy based on an Eulerian representation of the gas phase and Lagrangian tracking of the particles is developed in the framework of NGA, a high- order fully conservative parallel code tailored for turbulent flows. The particles are accounted for using a point-particle assumption. Once the gas-phase quantities are mapped to the particle location a conservative, implicit diffusion operation smoothes the field. Normal and tangential collisions are handled via soft-sphere model, modified to allow the bed to reach close packing at rest. The pressure drop across the bed is compared with theory to accurately predict the minimum fluidization velocity. 3D simulations of the National Renewable Energy Lab's 4-inch reactor are then conducted. Tens of millions of particles are tracked. The reactor's geometry is modeled using an immersed boundary scheme. Statistics for volume fraction, velocities, bed expansion, and bubble characteristics are analyzed and compared with experimental data.

  4. Apparatus for controlling fluidized beds

    DOEpatents

    Rehmat, A.G.; Patel, J.G.

    1987-05-12

    An apparatus and process are disclosed for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance. 2 figs.

  5. Apparatus for controlling fluidized beds

    DOEpatents

    Rehmat, Amirali G.; Patel, Jitendra G.

    1987-05-12

    An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

  6. Fluidized-bed combustion

    SciTech Connect

    Botros, P E

    1990-04-01

    This report describes the activities of the Morgantown Energy Technology Center's research and development program in fluidized-bed combustion from October 1, 1987, to September 30, 1989. The Department of Energy program involves atmospheric and pressurized systems. Demonstrations of industrial-scale atmospheric systems are being completed, and smaller boilers are being explored. These systems include vortex, multi-solid, spouted, dual-sided, air-cooled, pulsed, and waste-fired fluidized-beds. Combustion of low-rank coal, components, and erosion are being studied. In pressurized combustion, first-generation, combined-cycle power plants are being tested, and second-generation, advanced-cycle systems are being designed and cost evaluated. Research in coal devolatilization, metal wastage, tube corrosion, and fluidization also supports this area. 52 refs., 24 figs., 3 tabs.

  7. Fluidized bed charcoal particle production system

    SciTech Connect

    Sowards, N.K.

    1985-04-09

    A fluidized bed charcoal particle production system, including apparatus and method, wherein pieces of combustible waste, such as sawdust, fragments of wood, etc., are continuously disposed within a fluidized bed of a pyrolytic vessel. Preferably, the fluidized bed is caused to reach operating temperatures by use of an external pre-heater. The fluidized bed is situated above an air delivery system at the bottom of the vessel, which supports pyrolysis within the fluidized bed. Charcoal particles are thus formed within the bed from the combustible waste and are lifted from the bed and placed in suspension above the bed by forced air passing upwardly through the bed. The suspended charcoal particles and the gaseous medium in which the particles are suspended are displaced from the vessel into a cyclone mechanism where the charcoal particles are separated. The separated charcoal particles are quenched with water to terminate all further charcoal oxidation. The remaining off-gas is burned and, preferably, the heat therefrom used to generate steam, kiln dry lumber, etc. Preferably, the bed material is continuously recirculated and purified by removing tramp material.

  8. Fluidized bed boiler feed system

    DOEpatents

    Jones, Brian C.

    1981-01-01

    A fluidized bed boiler feed system for the combustion of pulverized coal. Coal is first screened to separate large from small particles. Large particles of coal are fed directly to the top of the fluidized bed while fine particles are first mixed with recycled char, preheated, and then fed into the interior of the fluidized bed to promote char burnout and to avoid elutriation and carryover.

  9. Particle withdrawal from fluidized bed systems

    DOEpatents

    Salvador, Louis A.; Andermann, Ronald E.; Rath, Lawrence K.

    1982-01-01

    Method and apparatus for removing ash formed within, and accumulated at the lower portion of, a fluidized bed coal gasification reactor vessel. A supplemental fluidizing gas, at a temperature substantially less than the average fluidized bed combustion operating temperature, is injected into the vessel and upwardly through the ash so as to form a discrete thermal interface region between the fluidized bed and the ash. The elevation of the interface region, which rises with ash accumulation, is monitored by a thermocouple and interrelated with a motor controlled outlet valve. When the interface rises above the temperature indicator, the valve opens to allow removal of some of the ash, and the valve is closed, or positioned at a minimum setting, when the interface drops to an elevation below that of the thermocouple.

  10. Kinetic behavior of solid particles in fluidized beds

    SciTech Connect

    Kono, H.O.

    1990-06-01

    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.

  11. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.; Marasco, Joseph A.

    1996-01-01

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary and tertiary particulate phases, continuously introduced and removed simultaneously in the cocurrent and countercurrent mode, act in a role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Means for introducing and removing the sorbent phases include feed screw mechanisms and multivane slurry valves.

  12. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.

    1993-01-01

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves.

  13. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.; Marasco, Joseph A.

    1995-01-01

    A fluidized bed reactor system utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves.

  14. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.

    1993-12-14

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase is described. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figures.

  15. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.; Marasco, J.A.

    1996-02-27

    A fluidized bed reactor system is described which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary and tertiary particulate phases, continuously introduced and removed simultaneously in the cocurrent and countercurrent mode, act in a role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Means for introducing and removing the sorbent phases include feed screw mechanisms and multivane slurry valves. 3 figs.

  16. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.; Marasco, J.A.

    1995-04-25

    A fluidized bed reactor system utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figs.

  17. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1992-08-01

    The general specifications for a Pulsed Atmospheric Fluidized Bed Combustor Design Report (PAFBC) plant are presented. The design tasks for the PAFBC are described in the following areas: Coal/Limestone preparation and feed system; pulse combustor; fluidized bed; boiler parts; and ash handling system.

  18. Fast fluidized bed steam generator

    DOEpatents

    Bryers, Richard W.; Taylor, Thomas E.

    1980-01-01

    A steam generator in which a high-velocity, combustion-supporting gas is passed through a bed of particulate material to provide a fluidized bed having a dense-phase portion and an entrained-phase portion for the combustion of fuel material. A first set of heat transfer elements connected to a steam drum is vertically disposed above the dense-phase fluidized bed to form a first flow circuit for heat transfer fluid which is heated primarily by the entrained-phase fluidized bed. A second set of heat transfer elements connected to the steam drum and forming the wall structure of the furnace provides a second flow circuit for the heat transfer fluid, the lower portion of which is heated by the dense-phase fluidized bed and the upper portion by the entrained-phase fluidized bed.

  19. Fluidized-bed combustion reduces atmospheric pollutants

    NASA Technical Reports Server (NTRS)

    Jonke, A. A.

    1972-01-01

    Method of reducing sulfur and nitrogen oxides released during combustion of fossil fuels is described. Fuel is burned in fluidized bed of solids with simultaneous feeding of crushed or pulverized limestone to control emission. Process also offers high heat transfer rates and efficient contacting for gas-solid reactions.

  20. Fluidized bed combustor modeling

    NASA Technical Reports Server (NTRS)

    Horio, M.; Rengarajan, P.; Krishnan, R.; Wen, C. Y.

    1977-01-01

    A general mathematical model for the prediction of performance of a fluidized bed coal combustor (FBC) is developed. The basic elements of the model consist of: (1) hydrodynamics of gas and solids in the combustor; (2) description of gas and solids contacting pattern; (3) kinetics of combustion; and (4) absorption of SO2 by limestone in the bed. The model is capable of calculating the combustion efficiency, axial bed temperature profile, carbon hold-up in the bed, oxygen and SO2 concentrations in the bubble and emulsion phases, sulfur retention efficiency and particulate carry over by elutriation. The effects of bed geometry, excess air, location of heat transfer coils in the bed, calcium to sulfur ratio in the feeds, etc. are examined. The calculated results are compared with experimental data. Agreement between the calculated results and the observed data are satisfactory in most cases. Recommendations to enhance the accuracy of prediction of the model are suggested.

  1. Development of methods to predict agglomeration and deposition in fluidized-bed combustion systems (FBCS). Topical report

    SciTech Connect

    Mann, M.D.; Henderson, A.K.; Swanson, M.L.; Allan, S.E.

    1996-02-01

    The successful design and operation of advanced combustion systems require the ability to control and mitigate ash-related problems. The major ash-related problems are slag flow control, slag attack on the refractory, ash deposition on heat-transfer surfaces, corrosion and erosion of equipment materials, and emissions control. These problems are the result of physical and chemical interactions of the fuels, bed materials, and system components. The interactions that take place and ultimately control ash behavior in fluidized-bed combustion (FBC) systems are controlled by the abundance and association of the inorganic components in coal and by the system conditions. Because of the complexity of the materials and processes involved, the design and operations engineer often lacks the information needed to predict ash behavior and reduce ash-related problems. The deposition of ashes from the fluidized bed combustion of lignite and petroleum coke is described in this paper.

  2. Control of acid gases using a fluidized bed adsorber.

    PubMed

    Chiang, Bo-Chin; Wey, Ming-Yen; Yeh, Chia-Lin

    2003-08-01

    During incineration, secondary pollutants such as acid gases, organic compounds, heavy metals and particulates are generated. Among these pollutants, the acid gases, including sulfur oxides (SO(x)) and hydrogen chloride (HCl), can cause corrosion of the incinerator piping and can generate acid rain after being emitted to the atmosphere. To address this problem, the present study used a novel combination of air pollution control devices (APCDs), composed of a fluidized bed adsorber integrated with a fabric filter. The major objective of the work is to demonstrate the performance of a fluidized bed adsorber for removal of acid gases from flue gas of an incinerator. The adsorbents added in the fluidized bed adsorber were mainly granular activated carbon (AC; with or without chemical treatment) and with calcium oxide used as an additive. The advantages of a fluidized bed reactor for high mass transfer and high gas-solid contact can enhance the removal of acid gases when using a dry method. On the other hand, because the fluidized bed can filter particles, fine particles prior to and after passing through the fluidized bed adsorber were investigated. The competing adsorption on activated carbon between different characteristics of pollutants was also given preliminary discussion. The results indicate that the removal efficiencies of the investigated acid gases, SO(2) and HCl, are higher than 94 and 87%, respectively. Thus, a fluidized bed adsorber integrated with a fabric filter has the potential to replace conventional APCDs, even when there are other pollutants at the same time.

  3. Particle pressures in fluidized beds

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Hu, X.; Jin, C.; Potapov, A.V.

    1992-01-01

    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.

  4. Pressurized fluidized bed reactor

    DOEpatents

    Isaksson, J.

    1996-03-19

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

  5. Pressurized fluidized bed reactor

    DOEpatents

    Isaksson, Juhani

    1996-01-01

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

  6. Control of bed height in a fluidized bed gasification system

    DOEpatents

    Mehta, Gautam I.; Rogers, Lynn M.

    1983-12-20

    In a fluidized bed apparatus a method for controlling the height of the fdized bed, taking into account variations in the density of the bed. The method comprises taking simultaneous differential pressure measurements at different vertical elevations within the vessel, averaging the differential pressures, determining an average fluidized bed density, then periodically calculating a weighting factor. The weighting factor is used in the determination of the actual bed height which is used in controlling the fluidizing means.

  7. Control of a Circulating Fluidized Bed

    SciTech Connect

    Shim, Hoowang; Rickards, Gretchen; Famouri, Parviz; Turton, Richard; Sams, W. Neal; Koduro, Praveen; Patankar, Amol; Davari, Assad; Lawson, Larry; Boyle, Edward J.

    2001-11-06

    Two methods for optimally controlling the operation of a circulating fluidized bed are being investigated, neural network control and Kalman filter control. The neural network controls the solids circulation rate by adjusting the flow of move air in the non-mechanical valve. Presented is the method of training the neural network from data generated by the circulating fluidized bed (CFB), the results of a sensitivity study indicating that adjusting the move air can control solids flow, and the results of controlling solids circulation rate. The Kalman filter approach uses a dynamic model and a measurement model of the standpipe section of the CFB. Presented are results showing that a Kalman filter can successfully find the standpipe bed height.

  8. Fluidized bed for production of polycrystalline silicon

    SciTech Connect

    Flagella, R.N.

    1992-08-18

    This patent describes a method for removing silicon powder particles from a reactor that produces polycrystalline silicon by the pyrolysis of a silane containing gas in a fluidized bed reaction zone of silicon seed particles. It comprises introducing the silane containing gas stream into the reaction zone of fluidized silicon seed particles; heterogeneously decomposing the silane containing gas under conditions; collecting the silicon product particles from the collection zone; and removing silicon powder particles from the reactor.

  9. Reactor for fluidized bed silane decomposition

    NASA Technical Reports Server (NTRS)

    Iya, Sridhar K. (Inventor)

    1989-01-01

    An improved heated fluidized bed reactor and method for the production of high purity polycrystalline silicon by silane pyrolysis wherein silicon seed particles are heated in an upper heating zone of the reactor and admixed with particles in a lower zone, in which zone a silane-containing gas stream, having passed through a lower cooled gas distribution zone not conducive to silane pyrolysis, contacts the heated seed particles whereon the silane is heterogeneously reduced to silicon.

  10. Zone heating for fluidized bed silane pyrolysis

    NASA Technical Reports Server (NTRS)

    Iya, Sridhar K. (Inventor)

    1987-01-01

    An improved heated fluidized bed reactor and method for the production of high purity polycrystalline silicon by silane pyrolysis wherein silicon seed particles are heated in an upper heating zone of the reactor and admixed with particles in a lower reaction zone, in which zone a silane-containing gas stream, having passed through a lower cooled gas distribution zone not conducive to silane pyrolysis, contacts the heated seed particles whereon the silane is heterogeneously reduced to silicon.

  11. Fines in fluidized bed silane pyrolysis

    NASA Technical Reports Server (NTRS)

    Hsu, G.; Hogle, R.; Rohatgi, N.; Morrison, A.

    1984-01-01

    Silicon deposition on silicon seed particles by silane pyrolysis in a fluidized-bed reactor is investigated as a low-cost, high-throughput method to produce high-purity polysilicon for solar-cell applications. Studies of fines, particles 0.1-10 microns diam, initiated from homogeneous decomposition in the reactor were conducted using 2 and 6-in-diam fluidized beds. The studies show functional dependences of fines elutriation on silane feed concentration, temperature, gas velocity, and bubble size. The observation that the fines elutriation is generally below 10 percent of the silicon-in-silane feed is attributed to scavenging by large particles in an environment of less free space for homogeneous nucleation. Preliminary results suggest that, with proper conditions and distributor design, high-silane-concentration (over 50 percent SiH4 in H2) feed may be used.

  12. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Use of fluidized bed combustion not feasible-general... FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion not... finds on a site-specific or generic basis that use of a method of fluidized bed combustion of...

  13. Consider nonfouling fluidized bed exchangers

    SciTech Connect

    Klaren, D.G.; Baiiie, R.E. )

    1989-07-01

    Applications for fluidized bed heat exchangers in various industries, their operating principles and a detailed analysis of their suitability for replacing double-pipe scraped-surface heat exchangers in lube oil plants are discussed. Development of the fluidized bed heat exchanger started in the early 70s and was totally dedicated to improvement of the multistage flash evaporator for sea water desalination. This resulted in a demonstration plant with a fluidized bed heat exchanger with a total heat transfer surface of over 1,000 m/sup 2/. Over an operating period of more than 15,000 hours untreated sea water was heated to more than 120{sup 0}C without any fouling in the tubes due to scale deposits.

  14. Fluidized Bed Asbestos Sampler Design and Testing

    SciTech Connect

    Karen E. Wright; Barry H. O'Brien

    2007-12-01

    A large number of samples are required to characterize a site contaminated with asbestos from previous mine or other industrial operations. Current methods, such as EPA Region 10’s glovebox method, or the Berman Elutriator method are time consuming and costly primarily because the equipment is difficult to decontaminate between samples. EPA desires a shorter and less costly method for characterizing soil samples for asbestos. The objective of this was to design and test a qualitative asbestos sampler that operates as a fluidized bed. The proposed sampler employs a conical spouted bed to vigorously mix the soil and separate fine particulate including asbestos fibers on filters. The filters are then analyzed using transmission electron microscopy for presence of asbestos. During initial testing of a glass prototype using ASTM 20/30 sand and clay fines as asbestos surrogates, fine particulate adhered to the sides of the glass vessel and the tubing to the collection filter – presumably due to static charge on the fine particulate. This limited the fines recovery to ~5% of the amount added to the sand surrogate. A second prototype was constructed of stainless steel, which improved fines recovery to about 10%. Fines recovery was increased to 15% by either humidifying the inlet air or introducing a voltage probe in the air space above the sample. Since this was not a substantial improvement, testing using the steel prototype proceeded without using these techniques. Final testing of the second prototype using asbestos suggests that the fluidized bed is considerably more sensitive than the Berman elutriator method. Using a sand/tremolite mixture with 0.005% tremolite, the Berman elutriator did not segregate any asbestos structures while the fluidized bed segregated an average of 11.7. The fluidized bed was also able to segregate structures in samples containing asbestos at a 0.0001% concentration, while the Berman elutriator method did not detect any fibers at this

  15. Three-zonal engineering method of heat calculation for fluidized bed furnaces based on data on commercial investigations of heat generation distribution during biomass combustion

    NASA Astrophysics Data System (ADS)

    Litun, D. S.; Ryabov, G. A.

    2016-02-01

    A three-zonal method of heat calculation of furnaces for combustion of biomass and low-caloric fuel in the fluidized bed is described. The method is based on equations of thermal and material balances that account for heat generation by fuel in the zone, heat-and-mass transfer heat exchange between the furnace media and surfaces that bound the zone, and heat-and-mass transfer between furnace zones. The calculation procedure for heat generation by fuel in the fluidized bed (FB) using the heat generation portion by the fuel is proposed. Based on commercial investigations, the main factors that affect the average temperature in the FB and the portion of fuel heat that is released in the FB are determined. Results of commercial investigations showed that the airflow coefficient in the FB should be recognized as the main operation parameter that affects the average temperature in the FB and, consequently, heat generation in the FB. The gas flow rate in the FB can be marked out as the second factor that affects the consumption degree of oxidizer supplied in the FB. Commercial investigations revealed that mixing is affected by the gas flow rate in the FB and the bed material particle size, which may be changed during the boiler operation because of the agglomeration of particles of sand and ash. The calculation processing of commercial investigations on a KM-75-40M boiler of a CHP-3 of an Arkhangelsk Pulp and Paper Mill (APPM), which was carried out using the inverse problem procedure by means of a developed computer program, determined the range of the fuel heat release share in the FB, which was 0.26-0.45 at an excess air factor of 0.59-0.93 in the bed, and the heat release share in the maximum temperature zone in the total heat release in the superbed space. The heat release share in the bed is determined as an approximating function of the excess air factor in the bed and the fluidization number. The research results can be used during designing boilers with the

  16. Char binder for fluidized beds

    DOEpatents

    Borio, Richard W.; Accortt, Joseph I.

    1981-01-01

    An arrangement that utilizes agglomerating coal as a binder to bond coal fines and recycled char into an agglomerate mass that will have suitable retention time when introduced into a fluidized bed 14 for combustion. The simultaneous use of coal for a primary fuel and as a binder effects significant savings in the elimination of non-essential materials and processing steps.

  17. Apparatus and process for controlling fluidized beds

    DOEpatents

    Rehmat, Amirali G.; Patel, Jitendra G.

    1985-10-01

    An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

  18. Method of and apparatus for preheating pressurized fluidized bed combustor and clean-up subsystem of a gas turbine power plant

    DOEpatents

    Cole, Rossa W.; Zoll, August H.

    1982-01-01

    In a gas turbine power plant having a pressurized fluidized bed combustor, gas turbine-air compressor subsystem and a gas clean-up subsystem interconnected for fluid flow therethrough, a pipe communicating the outlet of the compressor of the gas turbine-air compressor subsystem with the interior of the pressurized fluidized bed combustor and the gas clean-up subsystem to provide for flow of compressed air, heated by the heat of compression, therethrough. The pressurized fluidized bed combustor and gas clean-up subsystem are vented to atmosphere so that the heated compressed air flows therethrough and loses heat to the interior of those components before passing to the atmosphere.

  19. Validation of a 2.5D CFD model for cylindrical gas–solids fluidized beds

    SciTech Connect

    Li, Tingwen

    2015-09-25

    The 2.5D model recently proposed by Li et al. (Li, T., Benyahia, S., Dietiker, J., Musser, J., and Sun, X., 2015. A 2.5D computational method to simulate cylindrical fluidized beds. Chemical Engineering Science. 123, 236-246.) was validated for two cylindrical gas-solids bubbling fluidized bed systems. Different types of particles tested under various flow conditions were simulated using the traditional 2D model and the 2.5D model. Detailed comparison against the experimental measurements on solid concentration and velocity were conducted. Comparing to the traditional Cartesian 2D flow simulation, the 2.5D model yielded better agreement with the experimental data especially for the solid velocity prediction in the column wall region.

  20. Validation of a 2.5D CFD model for cylindrical gas–solids fluidized beds

    DOE PAGES

    Li, Tingwen

    2015-09-25

    The 2.5D model recently proposed by Li et al. (Li, T., Benyahia, S., Dietiker, J., Musser, J., and Sun, X., 2015. A 2.5D computational method to simulate cylindrical fluidized beds. Chemical Engineering Science. 123, 236-246.) was validated for two cylindrical gas-solids bubbling fluidized bed systems. Different types of particles tested under various flow conditions were simulated using the traditional 2D model and the 2.5D model. Detailed comparison against the experimental measurements on solid concentration and velocity were conducted. Comparing to the traditional Cartesian 2D flow simulation, the 2.5D model yielded better agreement with the experimental data especially for the solidmore » velocity prediction in the column wall region.« less

  1. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1992-05-01

    During this first quarter, a lab-scale water-cooled pulse combustor was designed, fabricated, and integrated with old pilot-scale PAFBC test systems. Characterization tests on this pulse combustor firing different kinds of fuel -- natural gas, pulverized coal and fine coal -- were conducted (without fluidized bed operation) for the purpose of finalizing PAFBC full-scale design. Steady-state tests were performed. Heat transfer performance and combustion efficiency of a coal-fired pulse combustor were evaluated.

  2. Review: granulation and fluidized beds

    SciTech Connect

    Kono, H.

    1981-01-01

    The history of granulation techniques is very long; however, the systematic study of the granulation phenomenon began only after 1950. The first, distinguished paper treating the fundamental binding mechanism of granules was published by Rumpf in 1958. Although there are several binding forces, the discussion in this paper is confined to granulation involving the capillary energy of a liquid-particle system. This technique has been applied widely and successfully to various fields of powder technology because of its advantages of simplicity and economy (ref. 2). Granules with diameters larger than 5 mm can be prepared efficiently by rotating-type granulators, such as a pan or a trommel (ref. 3, 4, 5). On the other hand, the purpose of fluidized-bed granulators (hereafter abbreviated as FBG) is to produce small granules with diameters from 0.3 to 3 mm (ref. 6). Because it contains a small amount of liquid, a fluidized-bed granulator has a fluidization state differing significantly from that of an ordinary fluidized bed. The dispersion of liquid and powder in the bed plays an important role in the granulation mechanism. This mechanism is compared to that of pan granulators, and the differences in characteristics are discussed.

  3. Fluidized-Bed Reactor With Zone Heating

    NASA Technical Reports Server (NTRS)

    Iya, Sridhar K.

    1989-01-01

    Deposition of silicon on wall suppressed. In new fluidized bed, silicon seed particles heated in uppermost zone of reactor. Hot particles gradually mix with lower particles and descend through fluidized bed. Lower wall of vessel kept relatively cool. Because silane enters at bottom and circulates through reactor pyrolized to silicon at high temperatures, silicon deposited on particles in preference wall. Design of fluidized bed for production of silicon greatly reduces tendency of silicon to deposit on wall of reaction vessel.

  4. Agglomeration-Free Distributor for Fluidized Beds

    NASA Technical Reports Server (NTRS)

    Ouyang, F.; Sinica, A.; Levenspiel, O.

    1986-01-01

    New gas distributor for fluidized beds prevents hot particles from reacting on it and forming hard crust. In reduction of iron ore in fluidized bed, ore particles do not sinter on distributor and perhaps clog it or otherwise interfere with gas flow. Distributor also relatively cool. In fluidized-bed production of silicon, inflowing silane does not decompose until within bed of hot silicon particles and deposits on them. Plates of spiral distributor arranged to direct incoming gas into spiral flow. Turbulence in flow reduces frequency of contact between fluidized-bed particles and distributor.

  5. Fluidization onset and expansion of gas-solid fluidized beds

    SciTech Connect

    Jones, O.C.; Shin, T.S.

    1984-08-01

    A simple, mass conservation-based, kinematic model is presented for accurately predicting both the onset of fluidization and the degree of (limit of) bed expansion in bubbling gas-solid fluidized beds. The model is consistant with inception correlations exisiting in the literature. Since the method has a sound physical basis, it might be expected to provide scaling between laboratory-scale fluidized beds and large-scale systems. This scaling ability, however, remains to be demonstrated as does the application to pressurized systems and where the terminal Reynolds numbers exceed 1000, (Archimedes numbers over about 3.2 x 10/sup 5/).

  6. A study of Cr(VI) in ashes from fluidized bed combustion of municipal solid waste: leaching, secondary reactions and the applicability of some speciation methods.

    PubMed

    Abbas, Z A; Steenari, B M; Lindqvist, O

    2001-01-01

    The use of the fluidized bed technique for the combustion of municipal solid waste is a rather new concept. This type of combustor produces ash residues with somewhat different properties than the residues generated from the traditional mass burn techniques. Therefore, chemical characterization and the investigation of toxic metals behavior during ash water reactions are necessary for the safe disposal of these residues. In the present work, the total elemental composition, mineralogy and leaching behavior of ashes from the combustion of municipal solid waste in a fluidized bed combustion boiler have been investigated. The cyclone ash and, in particular, the filter ash contained considerable amounts of soluble substances, thus giving leachates with high levels of Cl-, Na+, K+, Ca2 + and Al(IIl). On the other hand, the two ash fractions taken in the boiler, the bottom and hopper ashes, were much more stable with respect to the release of salts and heavy metals. Since Cr(VI) is mobile and toxic its release from combustion residues can pose environmental problem. Even though the total Cr contents were similar in all ashes studied, the bottom ash gave about a thousand times higher levels of Cr(VI) in test leachates than the hopper, cyclone and filter ashes. However, it was found that the leached amount of Cr(VI) from the bottom ash decreased significantly when bottom ash was mixed with the hopper ash. The most probable cause for this decrease is the coupled oxidation of Al(0) to Al(III) and reduction of dissolved Cr(VI) to Cr(III). This finding that the mixing of two ash streams from the same boiler could result in the immobilization of Cr may point at a simple stabilization method. Selective extraction of water soluble, exchangeable and sparingly soluble forms of Cr(VI) was also investigated. Extraction methods were evaluated for their suitability for ash matrixes. It was found that interferences due to the presence of reducing substances in some ash materials may

  7. Staged cascade fluidized bed combustor

    DOEpatents

    Cannon, Joseph N.; De Lucia, David E.; Jackson, William M.; Porter, James H.

    1984-01-01

    A fluid bed combustor comprising a plurality of fluidized bed stages interconnected by downcomers providing controlled solids transfer from stage to stage. Each stage is formed from a number of heat transfer tubes carried by a multiapertured web which passes fluidizing air to upper stages. The combustor cross section is tapered inwardly from the middle towards the top and bottom ends. Sorbent materials, as well as non-volatile solid fuels, are added to the top stages of the combustor, and volatile solid fuels are added at an intermediate stage.

  8. A fluidized bed enhances biotreatment

    SciTech Connect

    1996-03-01

    Chlorinated organics such as trichloroethylene (TCE) are often difficult to treat biologically because they degrade into intermediate compounds that are toxic to most microorganisms. But recent advances in fluidized bed biotreatment by Envirex, Inc. (Waukesha, Wis.) indicate that difficult-to-treat wastes like TCE can be successfully biodegraded. The key is to add chemicals (dubbed co-metabolic substrates), which promote the growth of microbes that preferentially degrade the unwanted intermediate compounds. Preliminary field tests using phenol, toluene and methane as the co-metabolic substrate show that TCE levels can be reduced by as much as 95%.

  9. Fluidized bed deposition of diamond

    DOEpatents

    Laia, Jr., Joseph R.; Carroll, David W.; Trkula, Mitchell; Anderson, Wallace E.; Valone, Steven M.

    1998-01-01

    A process for coating a substrate with diamond or diamond-like material including maintaining a substrate within a bed of particles capable of being fluidized, the particles having substantially uniform dimensions and the substrate characterized as having different dimensions than the bed particles, fluidizing the bed of particles, and depositing a coating of diamond or diamond-like material upon the substrate by chemical vapor deposition of a carbon-containing precursor gas mixture, the precursor gas mixture introduced into the fluidized bed under conditions resulting in excitation mechanisms sufficient to form the diamond coating.

  10. Design and Cold Mode Experiment of Dual Bubbling Fluidized Bed Reactors for Multiple CCR Cycles

    NASA Astrophysics Data System (ADS)

    Fang, F.; Li, Z. S.; Cai, N. S.

    The dual fluidized bed reactors are the key technology to fulfill the multiple CCR (calcination/carbonation reactions) cycles for CO2 capture from the flue gases. Firstly, the dual bubbling fluidized bed reactors were selected in this work based on analyzing different types of dual fluidized bed reactors. Secondly, the design method of dual fluidized bed reactors for CO2 capture with CCR concept was proposed. Thirdly, with the designed results, a cold mode of the dual bubbling fluidized bed reactors was built. The long-term stable operation and the continuous solid circulation between two reactors could be achieved successfully. The experimental results indicated that the solid circulation rate was increased with an increase of bed height, diameter of solid injection nozzle, and diameter of holes on the solid injection nozzle.

  11. Modeling of fluidized bed silicon deposition process

    NASA Technical Reports Server (NTRS)

    Kim, K.; Hsu, G.; Lutwack, R.; PRATURI A. K.

    1977-01-01

    The model is intended for use as a means of improving fluidized bed reactor design and for the formulation of the research program in support of the contracts of Silicon Material Task for the development of the fluidized bed silicon deposition process. A computer program derived from the simple modeling is also described. Results of some sample calculations using the computer program are shown.

  12. Continuous austempering fluidized bed furnace. Final report

    SciTech Connect

    Srinivasan, M.N.

    1997-09-23

    The intended objective of this project was to show the benefits of using a fluidized bed furnace for austenitizing and austempering of steel castings in a continuous manner. The division of responsibilities was as follows: (1) design of the fluidized bed furnace--Kemp Development Corporation; (2) fabrication of the fluidized bed furnace--Quality Electric Steel, Inc.; (3) procedure for austempering of steel castings, analysis of the results after austempering--Texas A and M University (Texas Engineering Experiment Station). The Department of Energy provided funding to Texas A and M University and Kemp Development Corporation. The responsibility of Quality Electric Steel was to fabricate the fluidized bed, make test castings and perform austempering of the steel castings in the fluidized bed, at their own expense. The project goals had to be reviewed several times due to financial constraints and technical difficulties encountered during the course of the project. The modifications made and the associated events are listed in chronological order.

  13. Fluidized bed coal combustion reactor

    NASA Technical Reports Server (NTRS)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  14. Fluidized bed coal combustion reactor

    SciTech Connect

    Moynihan, P.I.; Young, D.L.

    1981-09-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor. Official Gazette of the U.S. Patent and Trademark Office

  15. Fluidized bed heat treating system

    SciTech Connect

    Ripley, Edward B; Pfennigwerth, Glenn L

    2014-05-06

    Systems for heat treating materials are presented. The systems typically involve a fluidized bed that contains granulated heat treating material. In some embodiments a fluid, such as an inert gas, is flowed through the granulated heat treating medium, which homogenizes the temperature of the heat treating medium. In some embodiments the fluid may be heated in a heating vessel and flowed into the process chamber where the fluid is then flowed through the granulated heat treating medium. In some embodiments the heat treating material may be liquid or granulated heat treating material and the heat treating material may be circulated through a heating vessel into a process chamber where the heat treating material contacts the material to be heat treated. Microwave energy may be used to provide the source of heat for heat treating systems.

  16. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  17. Investigation of fluidized-bed biological denitrification

    SciTech Connect

    Acox, T.A.

    1982-12-16

    The performance of the fluidized-bed bioreactor was modelled for denitrification using a multiple linear regression. Reasonable accuracy was obtained; however, this type of analysis did not take into account the hydraulic characteristics of the fluidized-bed. The Mulcahy and LaMotta computer program previously used to model a fluidized-bed bioreactor cannot be used in this case due to the Michaelis-Menton constant k determined in this study, which was one to two orders of magnitude lower. With some additional bioreactor study and computer program modification, this may prove to be of some benefit.

  18. Tapered fluidized bed bioreactor for environmental control and fuel production

    SciTech Connect

    Scott, C. D.; Hancher, C. W.; Arcuri, E. J.

    1980-01-01

    Fluidized bed bioreactors are under development for use in environmental control and energy production. The most effective systems utilize a tapered portion either throughout the column or at the top of the column. This taper allows a wide range of operating conditions without loss of the fluidized particulates, and in general, results in more stable operation. The system described here utilize fixed films of microorganisms that have attached themselves to the fluidized particles. Preliminary investigations of the attachment indicate that reactor performance is related to film thickness. The biological denitrification of aqueous waste streams is typical of processes under development that utilize fluidized bed bioreactors. This development has progressed to the pilot plant scale where two 20-cm-diam x 800-cm fluidized beds in series accept aqueous wastes with nitrate concentrations as high as 10,000 mg/l and denitrification rates greater than 50 g/l/day using residence times of less than 30 minutes in each reactor. Other applications include aerobic degradation of phenolic wastes at rates greater than 25 g/l/day and the conversion of glucose to ethanol.

  19. Fluidized bed heating process and apparatus

    NASA Technical Reports Server (NTRS)

    McHale, Edward J. (Inventor)

    1981-01-01

    Capacitive electrical heating of a fluidized bed enables the individual solid particles within the bed to constitute the hottest portion thereof. This effect is achieved by applying an A. C. voltage potential between dielectric coated electrodes, one of which is advantageously the wall of the fluidized bed rejection zone, sufficient to create electrical currents in said particles so as to dissipate heat therein. In the decomposition of silane or halosilanes in a fluidized bed reaction zone, such heating enhances the desired deposition of silicon product on the surface of the seed particles within the fluidized bed and minimizes undesired coating of silicon on the wall of the reaction zone and the homogeneous formation of fine silicon powder within said zone.

  20. Drying of solids in fluidized beds

    SciTech Connect

    Kannan, C.S.; Thomas, P.P.; Varma, Y.B.G.

    1995-09-01

    Fluidized bed drying is advantageously adopted in industrial practice for drying of granular solids such as grains, fertilizers, chemicals, and minerals either for long shelf life or to facilitate further processing or handling. Solids are dried in batch and in continuous fluidized beds corresponding to cross-flow and countercurrent flow of phases covering a wide range in drying conditions. Materials that essentially dry with constant drying rate and then give a falling drying rate approximately linear with respect to solids moisture content (sand) as well as those with an extensive falling rate period with the subsequent falling rate being a curve with respect to the moisture content (mustard, ragi, poppy seeds) are chosen for the study. The performance of the continuous fluidized bed driers is compared with that of batch fluidized bed driers; the performance is predicted using batch kinetics, the residence time distribution of solids, and the contact efficiency between the phases.

  1. Fluidized bed combustor and tube construction therefor

    DOEpatents

    De Feo, Angelo; Hosek, William

    1981-01-01

    A fluidized bed combustor comprises a reactor or a housing which has a windbox distributor plate adjacent the lower end thereof which contains a multiplicity of hole and air discharge nozzles for discharging air and coal into a fluidized bed which is maintained above the distributor plate and below a take-off connection or flue to a cyclone separator in which some of the products of combustion are treated to remove the dust which is returned into the fluidized bed. A windbox is spaced below the fluidized bed and it has a plurality of tubes passing therethrough with the passage of combustion air and fluidizing air which passes through an air space so that fluidizing air is discharged into the reaction chamber fluidized bed at the bottom thereof to maintain the bed in a fluidized condition. A fluid, such as air, is passed through the tubes which extend through the windbox and provide a preheating of the combustion air and into an annular space between telescoped inner and outer tubes which comprise heat exchanger tubes or cooling tubes which extend upwardly through the distributor plate into the fluidized bed. The heat exchanger tubes are advantageously arranged so that they may be exposed in groups within the reactor in a cluster which is arranged within holding rings.

  2. Tube construction for fluidized bed combustor

    DOEpatents

    De Feo, Angelo; Hosek, William

    1984-01-01

    A fluidized bed combustor comprises a reactor or a housing which has a windbox distributor plate adjacent the lower end thereof which contains a multiplicity of hole and air discharge nozzles for discharging air and coal into a fluidized bed which is maintained above the distributor plate and below a take-off connection or flue to a cyclone separator in which some of the products of combustion are treated to remove the dust which is returned into the fluidized bed. A windbox is spaced below the fluidized bed and it has a plurality of tubes passing therethrough with the passage of combustion air and fluidizing air which passes through an air space so that fluidizing air is discharged into the reaction chamber fluidized bed at the bottom thereof to maintain the bed in a fluidized condition. A fluid, such as air, is passed through the tubes which extend through the windbox and provide a preheating of the combustion air and into an annular space between telescoped inner and outer tubes which comprise heat exchanger tubes or cooling tubes which extend upwardly through the distributor plate into the fluidized bed. The heat exchanger tubes are advantageously arranged so that they may be exposed in groups within the reactor in a cluster which is arranged within holding rings.

  3. Rivesville multicell fluidized bed boiler

    SciTech Connect

    Not Available

    1981-03-01

    One objective of the experimental MFB at Rivesville, WV, was the evaluation of alternate feed systems for injecting coal and limestone into a fluidized bed. A continuous, uniform feed flow to the fluid bed is essential in order to maintain stable operations. The feed system originally installed on the MFB was a gravity feed system with an air assist to help overcome the back pressure created by the fluid bed. The system contained belt, vibrating, and rotary feeders which have been proven adequate in other material handling applications. This system, while usable, had several operational and feeding problems during the MFB testing. A major portion of these problems occurred because the coal and limestone feed control points - a belt feeder and rotary feeder, respectively - were pressurized in the air assist system. These control points were not designed for pressurized service. An alternate feed system which could accept feed from the two control points, split the feed into six equal parts and eliminate the problems of the pressurized system was sought. An alternate feed system designed and built by the Fuller Company was installed and tested at the Rivesville facility. Fuller feed systems were installed on the north and south side of C cell at the Rivesville facility. The systems were designed to handle 10,000 lb/hr of coal and limestone apiece. The systems were installed in late 1979 and evaluated from December 1979 to December 1980. During this time period, nearly 1000 h of operating time was accumulated on each system.

  4. Rivesville multicell fluidized-bed boiler. Quarterly technical progress report, July-September 1980

    SciTech Connect

    1980-09-01

    The objective of this program is to design, construct and test a multicell fluidized-bed boiler as a pollution-free method of burning high-sulfur or highly corrosive coals without excessive maintenance problems. The fluidized-bed boiler will provide approximately 300,000 lb of steam per h. Steam pressure and temperature conditions were selected to meet requirements of the site at which the boiler was installed.

  5. A novel sorbent for transport reactors and fluidized bed reactors

    SciTech Connect

    Copeland, R.; Cesario, M.; Gershanovich, Y.; Sibold, J.; Windecker, B.

    1998-12-31

    Coal Fired Gasifier Combined Cycles (GCC) have both high efficiency and very low emissions. GCCs critically need a method of removing the H{sub 2}S produced from the sulfur in the coal from the hot gases. There has been extensive research on hot gas cleanup systems, focused on the use of a zinc oxide based sorbent (e.g., zinc titanate). TDA Research, Inc. (TDA) is developing a novel sorbent with improved attrition resistance for transport reactors and fluidized bed reactors. The authors are testing sorbents at conditions simulating the operating conditions of the Pinon Pine clean coal technology plant. TDA sulfided several different formulations at 538 C and found several that have high sulfur capacity when tested in a fluidized bed reactor. TDA initiated sorbent regeneration at 538 C. The sorbents retained chemical activity with multiple cycles. Additional tests will be conducted to evaluate the best sorbent formulation.

  6. Kinetic behavior of solid particles in fluidized beds: Annual report

    SciTech Connect

    Kono, H.O.; Huang, C.C.

    1987-10-01

    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.

  7. Hydrogen production with immobilized sewage sludge in three-phase fluidized-bed bioreactors.

    PubMed

    Wu, Shu-Yii; Lin, Chi-Num; Chang, Jo-Shu

    2003-01-01

    Municipal sewage sludge was immobilized with a modified alginate gel entrapment method, and the immobilized cells were used to produce hydrogen gas in a three-phase fluidized bed. The hydrogen-producing fluidized beds were operated at different liquid velocity (U(0)) and hydraulic retention time (HRT). The results show that in response to operating liquid velocities, the fluidized-bed system had three flow regimes, namely, plug flow, slug flow, and free bubbling. Pressure fluctuation analysis was used to analyze the hydrodynamic properties in this three-phase fluidized bed when it was under a steady-state production of biogas. With a steady-state biogas production rate (U(g)) of 0.196 mL/s/L, a transition state occurred at a liquid velocity (U(0)) of 0.85 cm/s. As U(0) < 0.85 cm/s, the system was basically a nonhomogeneous fluidized bed, whereas the bed became homogeneous when U(0) was higher than 0.85 cm/s. The fluidized bed can be stably carried out at high loading rates (HRT as low as 2 h). Hydrogen fermentation results show that the maximal hydrogen production rate was 0.93 L/h/L and the best yield (Y(H)2(/sucrose)) was 2.67 mol H(2)/mol sucrose.

  8. Lignite air-steam gasification in the fluidized bed of iron-containing slag catalysts

    SciTech Connect

    Kuznetsov, B.N.; Shchipko, M.L.; Golovin, Yu.

    1995-12-01

    The influence of fluidized bed of iron-containing slag particles on air-steam gasification of powdered Kansk-Achinsk lignite in entrained flow was studied in pilot installation with productivity about 60 kg per hour. Slag of Martin process and boiler slag were used as catalytic active materials until their complete mechanical attrition. Two following methods of catalytic gasification of lignite were compared: the partial gasification in stationary fluidized bed of slag particles with degree of fuel conversion 40-70% and complete gasification in circulating bed of slag particles. In the first case only the most reactive part of fuel is gasified with the simultaneously formation of porous carbon residue with good sorption ability. It was found the catalytic fluidized bed improves heat transfer from combustion to reduction zone of gas-generator and increases the rate of fuel conversion at the temperature range 900-1000{degrees}C. At these temperatures the degree of conversion is depended considerably on the duration time of fuel particles in the catalytic fluidized bed. The influence of catalytic fluidized bed height and velocity of reaction mixture on the temperature profiles in the gas-generator was studied. The optimal relationship was found between the fluidized bed height and velocity of flow which makes possible to produce the gas with higher calorific value at maximum degree of fuel conversion.

  9. Fluidized bed selective pyrolysis of coal

    DOEpatents

    Shang, J.Y.; Cha, C.Y.; Merriam, N.W.

    1992-12-15

    The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyses the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step. 9 figs.

  10. Fluidized bed selective pyrolysis of coal

    DOEpatents

    Shang, Jer Y.; Cha, Chang Y.; Merriam, Norman W.

    1992-01-01

    The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyzes the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step.

  11. Perspectives for Fluidized Bed Nuclear Reactor Technology using Rotating Fluidized Beds in a Static Geometry

    NASA Astrophysics Data System (ADS)

    Broqueville, Axel De; Wilde, Juray De

    The new concept of a rotating fluidized bed in a static geometry opens perspectives for fluidized bed nuclear reactor technology and is experimentally and numerically investigated. With conventional fluidized bed technology, the maximum attainable power is rather limited and maximum at a certain fluidization gas flow rate. Using a rotating fluidized bed in a static geometry, the fluidization gas drives both the centrifugal force and the counteracting radial gas-solid drag force in a similar way. This allows operating the reactor at any chosen sufficiently high solids loading over a much wider fluidization gas flow rate range and in particular at much higher fluidization gas flow rates than with conventional fluidized bed reactor technology, offering increased flexibility with respect to cooling via the fluidization gas. Furthermore, the centrifugal force can be a multiple of earth gravity, allowing radial gas-solid slip velocities much higher than in conventional fluidized beds. The latter result in gas-solid heat transfer coefficients one or multiple orders of magnitude higher than in conventional fluidized beds. The combination of dense operation and high fluidization gas flow rates allows process intensification and a more compact reactor design.

  12. Granular filtration in a fluidized bed

    SciTech Connect

    Mei, J.S.; Yue, P.C.; Halow, J.S.

    1995-12-01

    Successful development of advanced coal-fired power conversion systems often require reliable and efficient cleanup devices which can remove particulate and gaseous pollutants from high-temperature high-pressure gas streams. A novel filtration concept for particulate cleanup has been developed at the Morgantown Energy Technology Center (METC) of the U.S. Department of Energy. The filtration system consists of a fine metal screen filter immersed in a fluidized bed of granular material. As the gas stream passes through the fluidized bed, a layer of the bed granular material is entrained and deposited at the screen surface. This material provides a natural granular filter to separate fine particles from the gas stream passing through the bed. Since the filtering media is the granular material supplied by the fluidized bed, the filter is not subjected to blinding like candle filters. Because only the inflowing gas, not fine particle cohesive forces, maintains the granular layer at the screen surface, once the thickness and permeability of the granular layer is stabilized, it remains unchanged as long as the in-flowing gas flow rate remains constant. The weight of the particles and the turbulent nature of the fluidized bed limits the thickness of the granular layer on the filter leading to a self-cleaning attribute of the filter. This paper presents work since then on a continuous filtration system. The continuous filtration testing system consisted of a filter, a two-dimensional fluidized-bed, a continuous powder feeder, a laser-based in-line particle counting, sizing, and velocimeter (PCSV), and a continuous solids feeding/bed material withdrawal system. The two-dimensional, transparent fluidized-bed allowed clear observation of the general fluidized state of the granular material and the conditions under which fines are captured by the granular layer.

  13. Enhanced durability of desulfurization sorbents for fluidized-bed applications

    SciTech Connect

    Gupta, R.P.; Gangwal, S.K.

    1991-06-01

    Advanced integrated gasification combined cycle (IGCC) power systems require the development of high-temperature desulfurization sorbents capable of removing hydrogen sulfide from coal gasifier down to very low levels. The objective of this investigation was to identify and demonstrate methods for enhancing the long-term chemical reactivity and mechanical strength of zinc ferrite, a leading regenerable sorbent, for fluidized-bed applications. Fluidized sorbent beds offer significant potential in IGCC systems because of their ability to control the highly exothermic regeneration involved. However, fluidized beds require a durable, attrition-resistant sorbent in the 100--300 {mu}m size range. A bench-scale high-temperature, high- pressure (HTHP) fluidized-bed reactor (7.6-cm I.D.) system capable of operating up to 24 atm and 800{degree}C was designed, built and tested. A total of 175 sulfidation-regeneration cycles were carried out using KRW-type coal gas with various zinc ferrite formulations. A number of sorbent manufacturing techniques including spray drying, impregnation, crushing and screening, and granulation were investigated. While fluidizable sorbents prepared by crushing durable pellets and screening had acceptable sulfur capacity, they underwent excessive attrition during multicycle testing. The sorbent formulations prepared by a proprietary technique were found to have excellent attrition resistance and acceptable chemical reactivity during multicycle testing. However, zinc ferrite was found to be limited to 550{degree}C, beyond which excessive sorbent weakening due to chemical transformations, e.g., iron oxide reduction, was observed.

  14. Fluidized bed catalytic coal gasification process

    DOEpatents

    Euker, Jr., Charles A.; Wesselhoft, Robert D.; Dunkleman, John J.; Aquino, Dolores C.; Gouker, Toby R.

    1984-01-01

    Coal or similar carbonaceous solids impregnated with gasification catalyst constituents (16) are oxidized by contact with a gas containing between 2 volume percent and 21 volume percent oxygen at a temperature between 50.degree. C. and 250.degree. C. in an oxidation zone (24) and the resultant oxidized, catalyst impregnated solids are then gasified in a fluidized bed gasification zone (44) at an elevated pressure. The oxidation of the catalyst impregnated solids under these conditions insures that the bed density in the fluidized bed gasification zone will be relatively high even though the solids are gasified at elevated pressure and temperature.

  15. Fluidized bed electrowinning of copper. Final report

    SciTech Connect

    1997-07-01

    The objectives of the study were to: design and construct a 10,000- amp fluidized bed electrowinning cell for the recovery of copper from acidic sulfate solutions; demonstrate the technical feasibility of continuous particle recirculation from the electrowinning cell with the ultimate goal of continuous particle removal; and measure cell efficiency as a function of operating conditions.

  16. Fluidization quality analyzer for fluidized beds

    DOEpatents

    Daw, C.S.; Hawk, J.A.

    1995-07-25

    A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence. 9 figs.

  17. Reversed flow fluidized-bed combustion apparatus

    DOEpatents

    Shang, Jer-Yu; Mei, Joseph S.; Wilson, John S.

    1984-01-01

    The present invention is directed to a fluidized-bed combustion apparatus provided with a U-shaped combustion zone. A cyclone is disposed in the combustion zone for recycling solid particulate material. The combustion zone configuration and the recycling feature provide relatively long residence times and low freeboard heights to maximize combustion of combustible material, reduce nitrogen oxides, and enhance sulfur oxide reduction.

  18. FBC: Gaining acceptance. [Fluidized Bed Combustion

    SciTech Connect

    Gawlicki, S.M.

    1991-04-01

    This article addresses the growing acceptance of fluidized bed combustion as a technology appropriate for use in dual-purpose power plants. The article reviews projects for cogeneration in California, a demonstration plant sponsored by the US Department of Energy in Ohio (this plant also incorporates combined cycle operation), and an electric power/greenhouse project in Pennsylvania.

  19. Fluidization quality analyzer for fluidized beds

    DOEpatents

    Daw, C. Stuart; Hawk, James A.

    1995-01-01

    A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence.

  20. Particle pressures in fluidized beds. Final report

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction), they impart to the bed. So rather than directly measure the particle pressure, the authors inferred the values of the elasticity from measurements of instability growth in liquid beds; the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined) and then working backwards to determine the unknown coefficients, including the elasticity.

  1. Particle Pressures in Fluidized Beds. Final report

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction): they impart to the bed. So rather than directly measure the particle pressure, we inferred the values of the elasticity from measurements of instability growth in liquid beds the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined)and then working backwards to determine the unknown coefficients, including the elasticity.

  2. Fluidized-Bed Silane-Decomposition Reactor

    NASA Technical Reports Server (NTRS)

    Iya, Sridhar K.

    1991-01-01

    Fluidized-bed pyrolysis reactor produces high-purity polycrystalline silicon from silane or halosilane via efficient heterogeneous deposition of silicon on silicon seed particles. Formation of silicon dust via homogeneous decomposition of silane minimized, and deposition of silicon on wall of reactor effectively eliminated. Silicon used to construct solar cells and other semiconductor products.

  3. Fluidized bed gasification of extracted coal

    DOEpatents

    Aquino, Dolores C.; DaPrato, Philip L.; Gouker, Toby R.; Knoer, Peter

    1986-01-01

    Coal or similar carbonaceous solids are extracted by contacting the solids in an extraction zone (12) with an aqueous solution having a pH above 12.0 at a temperature between 65.degree. C. and 110.degree. C. for a period of time sufficient to remove bitumens from the coal into said aqueous solution and the extracted solids are then gasified at an elevated pressure and temperature in a fluidized bed gasification zone (60) wherein the density of the fluidized bed is maintained at a value above 160 kg/m.sup.3. In a preferred embodiment of the invention, water is removed from the aqueous solution in order to redeposit the extracted bitumens onto the solids prior to the gasification step.

  4. Fluidized bed gasification of extracted coal

    DOEpatents

    Aquino, D.C.; DaPrato, P.L.; Gouker, T.R.; Knoer, P.

    1984-07-06

    Coal or similar carbonaceous solids are extracted by contacting the solids in an extraction zone with an aqueous solution having a pH above 12.0 at a temperature between 65/sup 0/C and 110/sup 0/C for a period of time sufficient to remove bitumens from the coal into said aqueous solution, and the extracted solids are then gasified at an elevated pressure and temperature in a fluidized bed gasification zone (60) wherein the density of the fluidized bed is maintained at a value above 160 kg/m/sup 3/. In a preferred embodiment of the invention, water is removed from the aqueous solution in order to redeposit the extracted bitumens onto the solids prior to the gasification step. 2 figs., 1 tab.

  5. Fluidized bed silicon deposition from silane

    NASA Technical Reports Server (NTRS)

    Hsu, George C. (Inventor); Levin, Harry (Inventor); Hogle, Richard A. (Inventor); Praturi, Ananda (Inventor); Lutwack, Ralph (Inventor)

    1982-01-01

    A process and apparatus for thermally decomposing silicon containing gas for deposition on fluidized nucleating silicon seed particles is disclosed. Silicon seed particles are produced in a secondary fluidized reactor by thermal decomposition of a silicon containing gas. The thermally produced silicon seed particles are then introduced into a primary fluidized bed reactor to form a fluidized bed. Silicon containing gas is introduced into the primary reactor where it is thermally decomposed and deposited on the fluidized silicon seed particles. Silicon seed particles having the desired amount of thermally decomposed silicon product thereon are removed from the primary fluidized reactor as ultra pure silicon product. An apparatus for carrying out this process is also disclosed.

  6. Solar heated fluidized bed gasification system

    NASA Technical Reports Server (NTRS)

    Qader, S. A. (Inventor)

    1981-01-01

    A solar-powered fluidized bed gasification system for gasifying carbonaceous material is presented. The system includes a solar gasifier which is heated by fluidizing gas and steam. Energy to heat the gas and steam is supplied by a high heat capacity refractory honeycomb which surrounds the fluid bed reactor zone. The high heat capacity refractory honeycomb is heated by solar energy focused on the honeycomb by solar concentrator through solar window. The fluid bed reaction zone is also heated directly and uniformly by thermal contact of the high heat capacity ceramic honeycomb with the walls of the fluidized bed reactor. Provisions are also made for recovering and recycling catalysts used in the gasification process. Back-up furnace is provided for start-up procedures and for supplying heat to the fluid bed reaction zone when adequate supplies of solar energy are not available.

  7. Development of fluidized bed cement sintering technology

    SciTech Connect

    Mukai, Katsuji

    1994-12-31

    In the new system presented in this paper, the cement clinker is sintered, not in a rotary kiln, but in two different furnaces: a spouted bed kiln and a fluidized bed kiln. The heat generated in the process of cooling the cement clinker is recovered by a fluidized bed cooler and a packed bed cooler, which are more efficient than the conventional coolers. Compared with the rotary kiln system, the new technology significantly reduces NO{sub x} emissions, appreciably cuts energy consumption, and reduces CO{sub 2} emissions as well. Thus, the new system is an efficient cement sintering system that is friendly to the global environment. In this paper, we describe this new technology as one of the applied technologies at an industrial level that is being developed in the Clean Coal Technology Project, and we present the results from test operations at our pilot plant.

  8. Rapid ignition of fluidized bed boiler

    DOEpatents

    Osborn, Liman D.

    1976-12-14

    A fluidized bed boiler is started up by directing into the static bed of inert and carbonaceous granules a downwardly angled burner so that the hot gases cause spouting. Air is introduced into the bed at a rate insufficient to fluidize the entire bed. Three regions are now formed in the bed, a region of lowest gas resistance, a fluidized region and a static region with a mobile region at the interface of the fluidized and static regions. Particles are transferred by the spouting action to form a conical heap with the carbonaceous granules concentrated at the top. The hot burner gases ignite the carbonaceous matter on the top of the bed which becomes distributed in the bed by the spouting action and bed movement. Thereafter the rate of air introduction is increased to fluidize the entire bed, the spouter/burner is shut off, and the entire fluidized bed is ignited.

  9. Cluster Dynamics in a Circulating Fluidized Bed

    SciTech Connect

    Guenther, C.P.; Breault, R.W.

    2006-11-01

    A common hydrodynamic feature in industrial scale circulating fluidized beds is the presence of clusters. The continuous formation and destruction of clusters strongly influences particle hold-up, pressure drop, heat transfer at the wall, and mixing. In this paper fiber optic data is analyzed using discrete wavelet analysis to characterize the dynamic behavior of clusters. Five radial positions at three different axial locations under five different operating were analyzed using discrete wavelets. Results are summarized with respect to cluster size and frequency.

  10. Use of glow discharge in fluidized beds

    NASA Technical Reports Server (NTRS)

    Wydeven, T.; Wood, P. C.; Ballou, E. V.; Spitze, L. A. (Inventor)

    1981-01-01

    Static charges and agglomerization of particles in a fluidized bed systems are minimized by maintaining in at least part of the bed a radio frequency glow discharge. This approach is eminently suitable for processes in which the conventional charge removing agents, i.e., moisture or conductive particle coatings, cannot be used. The technique is applied here to the disproportionation of calcium peroxide diperoxyhydrate to yield calcium superoxide, an exceptionally water and heat sensitive reaction.

  11. Particle pressures in fluidized beds. Annual report

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Hu, X.; Jin, C.

    1994-03-01

    Campbell and Wang (1991) showed that the particle pressures in gas-fluidized beds were largely generated by the passage of bubbles. In particular, they showed that the average particle pressure exerted on the side walls scaled with the average size of the bubble. This immediately brings to mind two questions: (1) what is it about bubbles that leads to particle pressure generation and (2) would there be measurable particle pressures in liquid-fluidized beds which, while unstable, do not bubble? This project is largely aimed at answering these two questions. To attack the first problem, the authors have built a two-dimensional gas-fluidized bed into which bubbles may be injected and the distribution of particle-pressure measured. For the latter, other experiments are being performed in liquid fluidized beds. However, it soon became apparent that the particle pressures generated in the liquid beds are extremely small. This has pointed that phase of the research in two directions. The first is the design and construction of a third, and more sensitive, from of the particle pressure transducer. The second approach arose from reflection on what ultimately was the utility of the current research. This led to the development of a generic stability model, in which all modeled terms are left unspecified. From analyzing this model, they have developed an experimental plan that, by measuring the characteristics of voidage disturbances and comparing with the theory, will allow them to back out appropriate values for the modeled terms. The results will not only yield insight into the particle pressure, but also of the fluid drag. The latter results may be used to evaluate common models for these terms.

  12. Gas distributor for fluidized bed coal gasifier

    DOEpatents

    Worley, Arthur C.; Zboray, James A.

    1980-01-01

    A gas distributor for distributing high temperature reaction gases to a fluidized bed of coal particles in a coal gasification process. The distributor includes a pipe with a refractory reinforced lining and a plurality of openings in the lining through which gas is fed into the bed. These feed openings have an expanding tapered shape in the downstream or exhaust direction which aids in reducing the velocity of the gas jets as they enter the bed.

  13. Pulsed atmospheric fluidized bed combustor apparatus

    DOEpatents

    Mansour, Momtaz N.

    1993-10-26

    A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g., organic and medical waste, drying materials, heating air, calcining and the like.

  14. Fluidized bed injection assembly for coal gasification

    DOEpatents

    Cherish, Peter; Salvador, Louis A.

    1981-01-01

    A coaxial feed system for fluidized bed coal gasification processes including an inner tube for injecting particulate combustibles into a transport gas, an inner annulus about the inner tube for injecting an oxidizing gas, and an outer annulus about the inner annulus for transporting a fluidizing and cooling gas. The combustibles and oxidizing gas are discharged vertically upward directly into the combustion jet, and the fluidizing and cooling gas is discharged in a downward radial direction into the bed below the combustion jet.

  15. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    SciTech Connect

    Not Available

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  16. Fluidized-bed biological nitrogen removal

    SciTech Connect

    Hosaka, Yukihisa; Minami, Takeshi; Nasuno, Sai )

    1991-08-01

    This article describes a compact process for nitrogen removal developed in Japan. It does not require the large amounts of land of current denitrification processes. The process uses a three-phase fluidized bed of granular anthracite to which the nitrifying bacteria adhere and are fluidized by the activated sludge in the reactor. The process was developed in response to the need for nitrogen and phosphorus removal from waste water to prevent the eutrophication of Tokyo Bay, Japan.

  17. [Intermediate experiment and mechanism analysis of flue gas desulfurization technology by circulating fluidized bed].

    PubMed

    Zhao, Xudong; Wu, Shaohua; Ma, Chunyuan; Qin, Yukun

    2002-03-01

    A new Circulating Fluidized Bed was designed for intermediate experiment of flue gas desulphurization, in which the flue gas flow rate was 3500 m3/h. By using it, the basic experiments were carried out to study the influence of Ca/S and supersaturated temperature on desulphurization efficiency and the effect of the recycling solid particle in the sulfur removal column on desulphurization performance. The results showed when Ca/S = 1.2, the desulphurization efficiency was increased by 15% through the recycle of solid particle; the gas velocity inside the bed could be designed higher. The mechanism analysis were also studied and the method to increase effective resident time was introduced.

  18. Status of the fluidized bed unit

    SciTech Connect

    Williams, P.M.; Wade, J.F.

    1994-06-01

    Rocky Flats has a serious mixed waste problem. No technology or company has a license and available facilities to remedy this dilemma. One solution under study is to use a catalytic fluidized bed unit to destroy the combustible portion of the mixed waste. The fluidized bed thermal treatment program at Rocky Flats is building on knowledge gained over twenty years of successful development activity. The FBU has numerous technical advantages over other thermal technologies to treat Rocky Flats` mixed waste, the largest being the lower temperature (700{degrees}C versus 1000{degrees}C) which reduces acid corrosion and mechanical failures and obviates the need for ceramic lining. Successful demonstrations have taken place on bench, pilot, and full-scale tests using radioactive mixed wastes. The program is approaching implementation and licensing of a production-scale fluidized bed system for the safe treatment of mixed waste. The measure for success on this project is the ability to work closely with the community to jointly solve problems and respond to concerns of mixed waste treatment at Rocky Flats.

  19. Pressurized Fluidized Bed Combustion of Sewage Sludge

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshizo; Nojima, Tomoyuki; Kakuta, Akihiko; Moritomi, Hiroshi

    A conceptual design of an energy recovering system from sewage sludge was proposed. This system consists of a pressurized fluidized bed combustor, a gas turbine, and a heat exchanger for preheating of combustion air. Thermal efficiency was estimated roughly as 10-25%. In order to know the combustion characteristics of the sewage sludge under the elevated pressure condition, combustion tests of the dry and wet sewage sludge were carried out by using laboratory scale pressurized fluidized bed combustors. Combustibility of the sewage sludge was good enough and almost complete combustion was achieved in the combustion of the actual wet sludge. CO emission and NOx emission were marvelously low especially during the combustion of wet sewage sludge regardless of high volatile and nitrogen content of the sewage sludge. However, nitrous oxide (N2O) emission was very high. Hence, almost all nitrogen oxides were emitted as the form of N2O. From these combustion tests, we judged combustion of the sewage sludge with the pressurized fluidized bed combustor is suitable, and the conceptual design of the power generation system is available.

  20. Constitutive laws in liquid-fluidized beds

    NASA Astrophysics Data System (ADS)

    Duru, Paul; Nicolas, Maxime; Hinch, John; Guazzelli, Élisabeth

    2002-02-01

    The objective of the present work is to test experimentally the two-phase modelling approach which is widely used in fluidization. A difficulty of this way of modelling fluidized beds is the use of empirical relations in order to close the system of equations describing the fluidized bed as a two-phase continuum, especially concerning the description of the solid phase. We performed an experimental investigation of the primary wavy instability of liquid-fluidized beds. Experiments demonstrate that the wave amplitude saturates up the bed and we were able to measure the precise shape of this voidage wave. We then related this shape to the unknown solid phase viscosity and pressure functions of a simple two-phase model with a Newtonian stress-tensor for the solid phase. We found the scaling laws and the particle concentration dependence for these two quantities. It appears that this simplest model is quite satisfactory to describe the one-dimensional voidage waves in the limited range of parameters that we have studied. In our experimental conditions, the drag on the particles nearly balances their weight corrected for buoyancy, the small imbalance being mostly accounted for by solid phase viscous stress with a much smaller contribution from the solid phase pressure.

  1. Single-stage fluidized-bed gasification

    NASA Astrophysics Data System (ADS)

    Lau, F. S.; Rue, D. M.; Weil, S. A.; Punwani, D. V.

    1982-04-01

    The single-stage fluidized-bed gasification process, in addition to being a simple system, maximizes gas production and allows the economic exploitation of small peat deposits. The objective of this gasification project is to conduct experiments in order to obtain data for designing a single-stage fluidized-bed gasifier, and to evaluate the economics of converting peat to synthesis gas and to SNG by this process. An existing high-temperature and high-pressure process development unit (PDU) was modified to permit the direct feeding of peat to the fluidized bed. Peat flows by gravity from the feed hopper through a 6-inch line to the screw-feeder conveyor. From there, it is fed to the bottom tee section of the reactor and transported into the gasification zone. Oxygen and steam are fed through a distributing ring into the reactor. Gasification reactions occur in the annulus formed by the reactor tube and a central standpipe. Peat ash is discharged from the reactor by overflowing into the standpipe and is collected in a solids receiver.

  2. Rivesville multicell fluidized bed boiler. Annual technical progress report. July 1978-June 1979

    SciTech Connect

    Not Available

    1980-08-01

    Design, construction and test program of a 300,000 lb/hr steam generating capacity multicell fluidized bed boiler (MFB), as a pollution free method of burning high-sulfur or highly corrosive coals, is being carried out. The concept involves burning fuels such as coal, in a fluidized bed of limestone particles that react with the sulfur compounds formed during combustion to reduce air pollution. Nitrogen oxide emissions are also reduced at the lower combustion temperatures. The CaSO/sub 4/ produced in the furnace is discharged with the ash or regenerated to CaO for reuse in the fluidized bed. Information is presented on continued operation of the Rivesville MFB steam generating plant in a commercial mode and for determining performance and emission characteristics; studies and tests on flyash characterization and reinjection, fuel feed eductors and needles, air distributor, corrosion-erosion and sulfur capture; engineering studies to improve MFB performance and reliability.

  3. Utilization of ventilation air methane as a supplementary fuel at a circulating fluidized bed combustion boiler.

    PubMed

    You, Changfu; Xu, Xuchang

    2008-04-01

    Ventilation air methane (VAM) accounts for 60-80% of the total emissions from coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible.

  4. Cold-Flow Circulating Fluidized-Bed Identification

    SciTech Connect

    Parviz Famouri

    2005-07-01

    In a variety of industrial applications, the use of a circulating fluidized bed (CFB) provides various advantages, such as reducing environmental pollution and increasing process efficiency. The application of circulating fluidized bed technology contributes to the improvement of gas-solid contact, reduction of the cross-sectional area with the use of higher superficial velocities, the use of the solids circulation rate as an additional control variable, and superior radial mixing, Grace et al. [1]. In order to improve raw material usage and utility consumption, optimization and control of CFB is very important, and an accurate, real time model is required to describe and quantify the process. Currently there is no accepted way to construct a reliable model for such a complex CFB system using traditional methods, especially at the pilot or industrial scale. Three major obstacles in characterizing the system are: 1) chaotic nature of the system; 2) non-linearity of the system, and 3) number of immeasurable unknowns internal to the system,[2]. Advanced control theories and methods have the ability to characterize the system, and can overcome all three of these obstacles. These methods will be discussed in this report.

  5. Pulsed atmospheric fluidized bed combustion. Final report

    SciTech Connect

    1998-03-01

    ThermoChem, under contract to the Department of Energy, conducted extensive research, development and demonstration work on a Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) to confirm that advanced technology can meet these performance objectives. The ThermoChem/MTCI PAFBC system integrates a pulse combustor with an atmospheric bubbling-bed type fluidized bed combustor (BFBC) In this modular configuration, the pulse combustor burns the fuel fines (typically less than 30 sieve or 600 microns) and the fluidized bed combusts the coarse fuel particles. Since the ThermoChem/MTCI PAFBC employs both the pulse combustor and the AFBC technologies, it can handle the full-size range of coarse and fines. The oscillating flow field in the pulse combustor provides for high interphase and intraparticle mass transfer rates. Therefore, the fuel fines essentially burn under kinetic control. Due to the reasonably high temperature (>1093 C but less than the temperature for ash fusion to prevent slagging), combustion of fuel fines is substantially complete at the exit of the pulse combustor. The additional residence time of 1 to 2 seconds in the freeboard of the PAFBC unit then ensures high carbon conversion and, in turn, high combustion efficiency. A laboratory unit was successfully designed, constructed and tested for over 600 hours to confirm that the PAFBC technology could meet the performance objectives. Subsequently, a 50,000 lb/hr PAFBC demonstration steam boiler was designed, constructed and tested at Clemson University in Clemson, South Carolina. This Final Report presents the detailed results of this extensive and successful PAFBC research, development and demonstration project.

  6. Transients in a circulating fluidized bed boiler

    NASA Astrophysics Data System (ADS)

    Baskakov, A. P.; Munts, V. A.; Pavlyuk, E. Yu.

    2013-11-01

    Transients in a circulating fluidized bed boiler firing biomass are considered. An attempt is made to describe transients with the use of concepts applied in the automatic control theory. The parameters calculated from an analysis of unsteady heat balance equations are compared with the experimental data obtained in the 12-MW boiler of the Chalmers University of Technology. It is demonstrated that these equations describe the transient modes of operation with good accuracy. Dependences for calculating the time constants of unsteady processes are obtained.

  7. Simulation of fluidized bed coal combustors

    NASA Technical Reports Server (NTRS)

    Rajan, R.

    1979-01-01

    The many deficiencies of previous work on simulation of fluidized bed combustion (FBC) processes are presented. An attempt is made to reduce these deficiencies, and to formulate a comprehensive FBC model taking into account the following elements: (1) devolatilization of coal and the subsequent combustion of volatiles and residual char; (2) sulfur dioxide capture by limestone; (3) NOx release and reduction of NOx by char; (4) attrition and elutriation of char and limestone; (5) bubble hydrodynamics; (6) solids mixing; (7) heat transfer between gas and solid, and solid and heat exchange surfaces; and (8) freeboard reactions.

  8. Spatiotemporal dynamics of a shallow fluidized bed.

    SciTech Connect

    Aranson, I. S.; Tsimring, L. S.; Clark, D. K.

    2000-12-05

    An experimental and theoretical study of the dynamics of an air-fluidized thin granular layer is presented. Near the threshold of instability, the system exhibits critical behavior with remarkably long transient dynamics. Above the threshold of fluidization the system undergoes a Hopf bifurcation as the layer starts to oscillate at a certain frequency due to a feedback between the layer dilation and the airflow rate. Based on our experimental data, we formulate a the simple dynamical model which describes the transition in a shallow fluidized bed.

  9. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    SciTech Connect

    Keith, Raymond E.; Heller, Thomas J.; Bush, Stuart A.

    1991-01-01

    This Annual Report on Colorado-Ute Electric Association's NUCLA Circulating Fluidized Bed (CFB) Demonstration Program covers the period from February 1987 through December 1988. The outline for presentation in this report includes a summary of unit operations along with individual sections covering progress in study plan areas that commenced during this reporting period. These include cold-mode shakedown and calibration, plant commercial performance statistics, unit start-up (cold), coal and limestone preparation and handling, ash handling system performance and operating experience, tubular air heater, baghouse operation and performance, materials monitoring, and reliability monitoring. During this reporting period, the coal-mode shakedown and calibration plan was completed. (VC)

  10. Combined fluidized bed retort and combustor

    DOEpatents

    Shang, Jer-Yu; Notestein, John E.; Mei, Joseph S.; Zeng, Li-Wen

    1984-01-01

    The present invention is directed to a combined fluidized bed retorting and combustion system particularly useful for extracting energy values from oil shale. The oil-shale retort and combustor are disposed side-by-side and in registry with one another through passageways in a partition therebetween. The passageways in the partition are submerged below the top of the respective fluid beds to preclude admixing or the product gases from the two chambers. The solid oil shale or bed material is transported through the chambers by inclining or slanting the fluidizing medium distributor so that the solid bed material, when fluidized, moves in the direction of the downward slope of the distributor.

  11. Packed fluidized bed blanket for fusion reactor

    DOEpatents

    Chi, John W. H.

    1984-01-01

    A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

  12. Electrode assembly for a fluidized bed apparatus

    DOEpatents

    Schora, Jr., Frank C.; Matthews, Charles W.; Knowlton, Ted M.

    1976-11-23

    An electrode assembly comprising a high voltage electrode having a generally cylindrical shape and being electrically connected to a high voltage source, where the cylinder walls may be open to flow of fluids and solids; an electrically grounded support electrode supporting said high voltage electrode by an electrically insulating support where both of the electrically grounded and electrically insulating support may be hollow; and an electrically grounded liner electrode arranged concentrically around both the high voltage and support electrodes. This assembly is specifically adapted for use in a fluidized bed chemical reactor as an improved heating means therefor.

  13. Nucla circulating atmospheric fluidized bed demonstration project

    SciTech Connect

    Not Available

    1991-01-31

    During the fourth quarter of 1990, steady-state performance testing at the Nucla Circulating Fluidized Bed (CFB) resumed under sponsorship of the US Department of Energy. Co-sponsorship of the Demonstration Test Program by the Electric Power Research Institute (EPRI) was completed on June 15, 1990. From October through December, 1990, Colorado-Ute Electric Association (CUEA) completed a total of 23 steady-state performance tests, 4 dynamic tests, and set operating records during November and December as the result of improved unit operating reliability. Highlight events and achievements during this period of operation are presented.

  14. Gas fluidized-bed stirred media mill

    DOEpatents

    Sadler, III, Leon Y.

    1997-01-01

    A gas fluidized-bed stirred media mill is provided for comminuting solid ticles. The mill includes a housing enclosing a porous fluidizing gas diffuser plate, a baffled rotor and stator, a hollow drive shaft with lateral vents, and baffled gas exhaust exit ports. In operation, fluidizing gas is forced through the mill, fluidizing the raw material and milling media. The rotating rotor, stator and milling media comminute the raw material to be ground. Small entrained particles may be carried from the mill by the gas through the exit ports when the particles reach a very fine size.

  15. Fluidized-Bed Cleaning of Silicon Particles

    NASA Technical Reports Server (NTRS)

    Rohatgi, Naresh K.; Hsu, George C.

    1987-01-01

    Fluidized-bed chemical cleaning process developed to remove metallic impurities from small silicon particles. Particles (250 micrometer in size) utilized as seed material in silane pyrolysis process for production of 1-mm-size silicon. Product silicon (1 mm in size) used as raw material for fabrication of solar cells and other semiconductor devices. Principal cleaning step is wash in mixture of hydrochloric and nitric acids, leaching out metals and carrying them away as soluble chlorides. Particles fluidized by cleaning solution to assure good mixing and uniform wetting.

  16. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Air-fluidized bed. 890.5160 Section 890.5160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed....

  17. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Air-fluidized bed. 890.5160 Section 890.5160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed....

  18. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Air-fluidized bed. 890.5160 Section 890.5160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed....

  19. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Air-fluidized bed. 890.5160 Section 890.5160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed....

  20. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Air-fluidized bed. 890.5160 Section 890.5160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed....

  1. Fermentation in a fluidized-bed reactor

    SciTech Connect

    Scott, C.D.

    1983-06-01

    A laboratory-scale fluidized-bed bioreactor system for the production of ethanol from a glucose solution using flocculating Zymomonas mobilis was studied. Although the results are preliminary, 2.5- to 3.8-cm-diameter systems were operated for more than 300 h using fluidized floc particles that are 1-2 mm in diameter. The ethanol production rate in the lower portion of the fluidized bed operating at 30/sup 0/C routinely exceeded 200 g/L x h and under some conditions was as high as 400 g/ L x h with a reactor residence time of a few minutes. This far surpasses the results obtained with a batch, stirred-tank reactor using yeast. Ethanol productivity based on the total reactor volume approached 100 g/L x h, and glucose conversion exceeded 95%. With continued research, even higher production rates will be possible as conditions are optimized and scale-up to larger systems will allow the establishment of technical feasibility.

  2. Granular behavior in gas-fluidized beds

    NASA Astrophysics Data System (ADS)

    Ojha, Rajesh Prasad

    This work investigates the behavior of granular materials driven by a uniform upward flow of gas within a vertical container. This arrangement is referred to as a gas-fluidized bed. For a bed with a large number of spherical grains, bulk properties of the sample, such as solids volume fraction (the percent of space occupied by solids) and gas pressure drop, are found to obey simple scaling relations when the superficial air velocity, the container size, or the grain size are varied. These results stand in contrast to behavior observed in other granular systems, where non-trivial interaction between individual grains leads to complex behavior for the bulk. The results suggest that there is a unique quality to the forcing provided to individual grains by gas fluidization that results in relatively simple bulk behavior. To investigate this possibility, experiments were carried out in a gas-fluidized bed with only a single grain. A large grain, a ping pong ball, was chosen for ease of visual observation. The ball's behavior is found to be exactly that of a Brownian object harmonically bound to the center of its container. Its dynamics are found to be described by a Langevin Equation, with the random forcing on related to the dissipation of energy by the Fluctuation-Dissipation Theorem. We find that the separation statistics for a two-ball system are also described by a statistical mechanics approach. These results represent the first successful application of conventional statistical mechanics to a macroscopic system.

  3. Surface-renewal models for heat-transfer between walls and fluidized beds

    NASA Technical Reports Server (NTRS)

    Patel, R. D.

    1969-01-01

    Two surface-renewed film penetration models describe transient heat-transfer between a wall and a fluidized bed. Methods are presented for estimation of mean residence times of particles at the transporting surface, their age densities and the average transport coefficients.

  4. Modeling biomass gasification in circulating fluidized beds

    NASA Astrophysics Data System (ADS)

    Miao, Qi

    In this thesis, the modeling of biomass gasification in circulating fluidized beds was studied. The hydrodynamics of a circulating fluidized bed operating on biomass particles were first investigated, both experimentally and numerically. Then a comprehensive mathematical model was presented to predict the overall performance of a 1.2 MWe biomass gasification and power generation plant. A sensitivity analysis was conducted to test its response to several gasifier operating conditions. The model was validated using the experimental results obtained from the plant and two other circulating fluidized bed biomass gasifiers (CFBBGs). Finally, an ASPEN PLUS simulation model of biomass gasification was presented based on minimization of the Gibbs free energy of the reaction system at chemical equilibrium. Hydrodynamics plays a crucial role in defining the performance of gas-solid circulating fluidized beds (CFBs). A 2-dimensional mathematical model was developed considering the hydrodynamic behavior of CFB gasifiers. In the modeling, the CFB riser was divided into two regions: a dense region at the bottom and a dilute region at the top of the riser. Kunii and Levenspiel (1991)'s model was adopted to express the vertical solids distribution with some other assumptions. Radial distributions of bed voidage were taken into account in the upper zone by using Zhang et al. (1991)'s correlation. For model validation purposes, a cold model CFB was employed, in which sawdust was transported with air as the fluidizing agent. A comprehensive mathematical model was developed to predict the overall performance of a 1.2 MWe biomass gasification and power generation demonstration plant in China. Hydrodynamics as well as chemical reaction kinetics were considered. The fluidized bed riser was divided into two distinct sections: (a) a dense region at the bottom of the bed where biomass undergoes mainly heterogeneous reactions and (b) a dilute region at the top where most of homogeneous

  5. Sorbent utilization prediction methodology: sulfur control in fluidized-bed combustors

    SciTech Connect

    Fee, D.C.; Wilson, W.I.; Shearer, J.A.; Smith, G.W.; Lenc, J.F.; Fan, L.S.; Myles, K.M.; Johnson, I.

    1980-09-01

    The United States Government has embarked on an ambitious program to develop and commercialize technologies to efficiently extract energy from coal in an environmentally acceptable manner. One of the more promising new technologies for steam and power generation is the fluidized-bed combustion of coal. In this process, coal is burned in a fluidized bed composed mainly of calcined limestone sorbent. The calcium oxide reacts chemically to capture the sulfur dioxide formed during the combustion and to maintain the stack gas sulfur emissions at acceptable levels. The spent sulfur sorbent, containing calcium sulfate, is a dry solid that can be disposed of along with coal ash or potentially used. Other major advantages of fluidized-bed combustion are the reduction in nitrogen oxide emissions because of the relatively low combustion temperatures, the capability of burning wide varieties of fuel, the high carbon combustion efficiencies, and the high heat-transfer coefficients. A key to the widespread commercialization of fluidized-bed technology is the ability to accurately predict the amount of sulfur that will be captured by a given sorbent. This handbook meets this need by providing a simple, yet reliable, user-oriented methodology (the ANL method) that allows performance of a sorbent to be predicted. The methodology is based on only three essential sorbent parameters, each of which can be readily obtained from standardized laboratory tests. These standard tests and the subsequent method of data reduction are described in detail.

  6. Nucla circulating atmospheric fluidized bed demonstration project

    SciTech Connect

    Keith, Raymond E.

    1991-10-01

    Colorado-Ute Electric Association began a study to evaluate options for upgrading and extending the life of its Nucla power station in 1982. Located in southwestern Colorado near the town of Nucla, this station was commissioned in 1959 with a local bituminous coal as its design fuel for three identical stoker-fired units, each rated at 12.6 MW(e). Poor station efficiency, high fuel costs, and spiraling boiler maintenance costs forced the Nucla Station into low priority in the CUEA dispatch order as early as 1981. Among the options CUEA considered was to serve as a host utility to demonstrate Atmospheric Fluidized Bed Combustion (AFBC) technology. The anticipated environmental benefits and apparent attractive economics of a circulating AFBC led to Colorado-Ute's decision to proceed with the design and construction of a demonstration project in 1984 at the Nucla facility.

  7. Advanced control strategies for fluidized bed dryers

    SciTech Connect

    Siettos, C.I.; Kiranoudis, C.T.; Bafas, G.V.

    1999-11-01

    Generating the best possible control strategy comprises a necessity for industrial processes, by virtue of product quality, cost reduction and design simplicity. Three different control approaches, namely an Input-Output linearizing, a fuzzy logic and a PID controller, are evaluated for the control of a fluidized bed dryer, a typical non-linear drying process of wide applicability. Based on several closed loop characteristics such as settling times, maximum overshoots and dynamic performance criteria such as IAE, ISE and ITAE, it is shown that the Input-Output linearizing and the fuzzy logic controller exhibit a better performance compared to the PID controller tuned optimally with respect to IAE, for a wide range of disturbances; yet, the relevant advantage of the fuzzy logic over the conventional nonlinear controller issues upon its design simplicity. Typical load rejection and set-point tracking examples are given to illustrate the effectiveness of the proposed approach.

  8. Solids feed nozzle for fluidized bed

    DOEpatents

    Zielinski, Edward A.

    1982-01-01

    The vertical fuel pipe of a fluidized bed extends up through the perforated support structure of the bed to discharge granulated solid fuel into the expanded bed. A cap, as a deflecting structure, is supported above the discharge of the fuel pipe and is shaped and arranged to divert the carrier fluid and granulated fuel into the combusting bed. The diverter structure is spaced above the end of the fuel pipe and provided with a configuration on its underside to form a venturi section which generates a low pressure in the stream into which the granules of solid fuel are drawn to lengthen their residence time in the combustion zone of the bed adjacent the fuel pipe.

  9. Fluidized bed silicon deposition from silane

    NASA Technical Reports Server (NTRS)

    Hsu, George (Inventor); Levin, Harry (Inventor); Hogle, Richard A. (Inventor); Praturi, Ananda (Inventor); Lutwack, Ralph (Inventor)

    1984-01-01

    A process and apparatus for thermally decomposing silicon containing gas for deposition on fluidized nucleating silicon seed particles is disclosed. Silicon seed particles are produced in a secondary fluidized reactor by thermal decomposition of a silicon containing gas. The thermally produced silicon seed particles are then introduced into a primary fluidized bed reactor to form a fludized bed. Silicon containing gas is introduced into the primary reactor where it is thermally decomposed and deposited on the fluidized silicon seed particles. Silicon seed particles having the desired amount of thermally decomposed silicon product thereon are removed from the primary fluidized reactor as ultra pure silicon product. An apparatus for carrying out this process is also disclosed.

  10. Fluidized bed boiler having a segmented grate

    DOEpatents

    Waryasz, Richard E.

    1984-01-01

    A fluidized bed furnace (10) is provided having a perforate grate (9) within a housing which supports a bed of particulate material including some combustibles. The grate is divided into a plurality of segments (E2-E6, SH1-SH5, RH1-RH5), with the airflow to each segment being independently controlled. Some of the segments have evaporating surface imbedded in the particulate material above them, while other segments are below superheater surface or reheater surface. Some of the segments (E1, E7) have no surface above them, and there are ignitor combustors (32, 34) directed to fire into the segments, for fast startup of the furnace without causing damage to any heating surface.

  11. Pulsed atmospheric fluidized bed combustion. Final report

    SciTech Connect

    Not Available

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  12. Flow cytometric viability assessment of lactic acid bacteria starter cultures produced by fluidized bed drying.

    PubMed

    Bensch, Gerald; Rüger, Marc; Wassermann, Magdalena; Weinholz, Susann; Reichl, Udo; Cordes, Christiana

    2014-06-01

    For starter culture production, fluidized bed drying is an efficient and cost-effective alternative to the most frequently used freeze drying method. However, fluidized bed drying also poses damaging or lethal stress to bacteria. Therefore, investigation of impact of process variables and conditions on viability of starter cultures produced by fluidized bed drying is of major interest. Viability of bacteria is most frequently assessed by plate counting. While reproductive growth of cells can be characterized by the number of colony-forming units, it cannot provide the number of viable-but-nonculturable cells. However, in starter cultures, these cells still contribute to the fermentation during food production. In this study, flow cytometry was applied to assess viability of Lactobacillus plantarum starter cultures by membrane integrity analysis using SYBR®Green I and propidium iodide staining. The enumeration method established allowed for rapid, precise and sensitive determination of viable cell concentration, and was used to investigate effects of fluidized bed drying and storage on viability of L. plantarum. Drying caused substantial membrane damage on cells, most likely due to dehydration and oxidative stress. Nevertheless, high bacterial survival rates were obtained, and granulates contained in the average 2.7 × 10(9) viable cells/g. Furthermore, increased temperatures reduced viability of bacteria during storage. Differences in results of flow cytometry and plate counting suggested an occurrence of viable-but-nonculturable cells during storage. Overall, flow cytometric viability assessment is highly feasible for rapid routine in-process control in production of L. plantarum starter cultures, produced by fluidized bed drying.

  13. Bifurcation analysis of bubble dynamics in fluidized beds

    SciTech Connect

    Blomgren, Peter; Palacios, Antonio; Zhu, Bing; Daw, C Stuart; FINNEY, Charles E A; Halow, John; Pannala, Sreekanth

    2007-01-01

    We use a low-dimensional, agent-based bubble model to study the changes in the global dynamics of fluidized beds in response to changes in the frequency of the rising bubbles. The computationally based bifurcation analysis shows that at low frequencies, the global dynamics is attracted towards a fixed point since the bubbles interact very little with one another. As the frequency of injection increases, however, the global dynamics undergoes a series of bifurcations to new behaviors that include highly periodic orbits, chaotic attractors, and intermittent behavior between periodic orbits and chaotic sets. Using methods from time-series analysis, we are able to approximate nonlinear models that allow for long-term predictions and the possibility of developing control algorithms.

  14. Computational Fluid Dynamics Simulation of Fluidized Bed Polymerization Reactors

    SciTech Connect

    Fan, Rong

    2006-01-01

    , monovariate population balance, bivariate population balance, aggregation and breakage equation and DQMOM-Multi-Fluid model are described. In the last section of Chapter 3, numerical methods involved in the multi-fluid model and time-splitting method are presented. Chapter 4 is based on a paper about application of DQMOM to polydisperse gas-solid fluidized beds. Results for a constant aggregation and breakage kernel and a kernel developed from kinetic theory are shown. The effect of the aggregation success factor and the fragment distribution function are investigated. Chapter 5 shows the work on validation of mixing and segregation phenomena in gas-solid fluidized beds with a binary mixture or a continuous size distribution. The simulation results are compared with available experiment data and discrete-particle simulation. Chapter 6 presents the project with Univation Technologies on CFD simulation of a Polyethylene pilot-scale FB reactor, The fluid dynamics, mass/heat transfer and particle size distribution are investigated through CFD simulation and validated with available experimental data. The conclusions of this study and future work are discussed in Chapter 7.

  15. Linear system identification of a cold flow circulating fluidized bed

    SciTech Connect

    Panday, R; Woerner, B D; Ludlow, J C; Shadle, L J; Boyle, E J

    2009-02-01

    Knowledge of the solids circulation rate (SCR) is essential to the control and improved performance of a circulating fluidized bed system. In the present work, the noise model is derived using the prediction error method considering process and measurement noises acting on the cold flow circulating fluidized bed (CFCFB) with a cork particulate material. The outputs of the initial model are the total pressure drop across the riser, the pressure drop across the crossover, the pressure drop across the primary cyclone, the total pressure drop across the stand-pipe, the pressure drop across the loop seal, and the SCR. The stochastic estimate of SCR is determined from the noise model using the stochastic pressure drop estimates. The deterministic estimate is obtained through the inputs taken as move air flow, riser aeration, and loop seal fluidization air that are all independent variables of the given setup and under the control of the user. The theory has been developed to convert a complete blackbox model to a grey box model through the output-to-state transformation such that both the models of the CFCFB consists of all these output variables as the states of the system, and only pressure drops across the system as the output measurements. Thus, the final models do not include any fictitious terms and they are defined only in terms of physical parameters of the given system. Both components of SCR are separately analysed. The combined SCR response of both the noise model and deterministic model is compared with the validation data set of this state variable in terms of modelfit, and the results are shown.

  16. Model of Fluidized Bed Containing Reacting Solids and Gases

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Lathouwers, Danny

    2003-01-01

    A mathematical model has been developed for describing the thermofluid dynamics of a dense, chemically reacting mixture of solid particles and gases. As used here, "dense" signifies having a large volume fraction of particles, as for example in a bubbling fluidized bed. The model is intended especially for application to fluidized beds that contain mixtures of carrier gases, biomass undergoing pyrolysis, and sand. So far, the design of fluidized beds and other gas/solid industrial processing equipment has been based on empirical correlations derived from laboratory- and pilot-scale units. The present mathematical model is a product of continuing efforts to develop a computational capability for optimizing the designs of fluidized beds and related equipment on the basis of first principles. Such a capability could eliminate the need for expensive, time-consuming predesign testing.

  17. Detection of lateral non-uniformities in fluidized bed combustors

    SciTech Connect

    Ramayya, A.V.; Thiyagarajan, A.; Ahmed, S.A.

    1997-12-01

    This paper addresses the detection of lateral non-Uniformities in fluidized bed combustors by a novel probe technique not reported so far, by using the horizontal differential pressure fluctuations associated with bubble flow. The salient features of these fluctuations are highlighted utilizing the simulated records obtained by considering the Davidson`s pressure field around a bubble. The simulation approach is validated by a comparison with the measured vertical and horizontal differential fluctuations in a freely bubbling fluidized bed.

  18. Fluidized-bed calciner with combustion nozzle and shroud

    DOEpatents

    Wielang, Joseph A.; Palmer, William B.; Kerr, William B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition.

  19. Particle pressures in fluidized beds. First year annual report

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Hu, X.; Jin, C.; Potapov, A.V.

    1992-09-01

    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.

  20. CFD-DEM study of effect of bed thickness for bubbling fluidized beds

    SciTech Connect

    Tingwen, Li; Gopalakrishnan, Pradeep; Garg, Rahul; Shahnam, Mehrdad

    2011-10-01

    The effect of bed thickness in rectangular fluidized beds is investigated through the CFD–DEM simulations of small-scale systems. Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing, bed expansion, bubble behavior, solids velocities, and particle kinetic energy. Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters. However, a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters, indicating the transition from 2D flow to 3D flow within the range of 20–40 particle diameters. Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds. Hence, for quantitative comparison with experiments in pseudo-2D columns, the effect of walls has to be accounted for in numerical simulations.

  1. COMPUTATIONAL MODELING OF CIRCULATING FLUIDIZED BED REACTORS

    SciTech Connect

    Ibrahim, Essam A

    2013-01-09

    Details of numerical simulations of two-phase gas-solid turbulent flow in the riser section of Circulating Fluidized Bed Reactor (CFBR) using Computational Fluid Dynamics (CFD) technique are reported. Two CFBR riser configurations are considered and modeled. Each of these two riser models consist of inlet, exit, connecting elbows and a main pipe. Both riser configurations are cylindrical and have the same diameter but differ in their inlet lengths and main pipe height to enable investigation of riser geometrical scaling effects. In addition, two types of solid particles are exploited in the solid phase of the two-phase gas-solid riser flow simulations to study the influence of solid loading ratio on flow patterns. The gaseous phase in the two-phase flow is represented by standard atmospheric air. The CFD-based FLUENT software is employed to obtain steady state and transient solutions for flow modulations in the riser. The physical dimensions, types and numbers of computation meshes, and solution methodology utilized in the present work are stated. Flow parameters, such as static and dynamic pressure, species velocity, and volume fractions are monitored and analyzed. The differences in the computational results between the two models, under steady and transient conditions, are compared, contrasted, and discussed.

  2. Silicon production in a fluidized bed reactor

    NASA Technical Reports Server (NTRS)

    Rohatgi, N. K.

    1986-01-01

    Part of the development effort of the JPL in-house technology involved in the Flat-Plate Solar Array (FSA) Project was the investigation of a low-cost process to produce semiconductor-grade silicon for terrestrial photovoltaic cell applications. The process selected was based on pyrolysis of silane in a fluidized-bed reactor (FBR). Following initial investigations involving 1- and 2-in. diameter reactors, a 6-in. diameter, engineering-scale FBR was constructed to establish reactor performance, mechanism of silicon deposition, product morphology, and product purity. The overall mass balance for all experiments indicates that more than 90% of the total silicon fed into the reactor is deposited on silicon seed particles and the remaining 10% becomes elutriated fines. Silicon production rates were demonstrated of 1.5 kg/h at 30% silane concentration and 3.5 kg/h at 80% silane concentration. The mechanism of silicon deposition is described by a six-path process: heterogeneous deposition, homogeneous decomposition, coalescence, coagulation, scavenging, and heterogeneous growth on fines. The bulk of the growth silicon layer appears to be made up of small diameter particles. This product morphology lends support to the concept of the scavenging of homogeneously nucleated silicon.

  3. Study of the heat transfer mechanism from a submerged pulse combustor to a fluidized bed

    NASA Astrophysics Data System (ADS)

    Jeong, Hae-Won

    The objective of this study was to develop a better understanding of the heat transfer mechanism from the oscillating flow in a pulse combustor tail pipe to a fluidized bed. Heat transfer in the pipe and to the bed was studied both theoretically and experimentally. A quasi-steady theory was used to predict the internal heat transfer coefficients in pulsating flow. A packet renewal theory was used to predict the external heat transfer coefficients. A pipe fitted with an electrical heater and four acoustic drivers, which can be submerged in a fluidized bed, simulated the tail pipe of a pulse combustor. Local internal heat transfer rates in the pipe were measured using an enthalpy difference method. Local flow velocities were measured using a hot-film probe and radial temperatures by a thermocouple. The results of this study have shown that a resonant acoustic field increases the local heat transfer rates at the acoustic velocity anti-node and decreases those at the node. These enhancements seem to be caused by a steeper radial temperature gradient near the wall. The overall heat transfer rate is enhanced, when the ratio of acoustic to mean velocity is greater than 1, i.e., when flow reversal occurs. The degree of heat transfer rate enhancement increases as the resonant frequency increases, but decreases as Reynolds number increases. In very turbulent flow pulsations provide no enhancement. A quasi-steady model was developed, which accurately predicts the heat transfer coefficients, for the tail pipe in natural convection (outside fluidized bed) especially when the ratio of acoustic to mean velocity is greater than 3. However, the model somewhat under predicts the heat transfer coefficients for the tail pipe in forced convection (inside fluidized bed). Pulsations inside a submerged tail pipe cause relatively small increase of fluidized bed temperature for low Reynolds number flow, and do not affect the bed temperature measurably for high Reynolds numbers. The rate

  4. Concentration and Velocity Gradients in Fluidized Beds

    NASA Technical Reports Server (NTRS)

    McClymer, James P.

    2003-01-01

    In this work we focus on the height dependence of particle concentration, average velocity components, fluctuations in these velocities and, with the flow turned off, the sedimentation velocity. The latter quantities are measured using Particle Imaging Velocimetry (PIV). The PIV technique uses a 1-megapixel camera to capture two time-displaced images of particles in the bed. The depth of field of the imaging system is approximately 0.5 cm. The camera images a region with characteristic length of 2.6 cm for the small particles and 4.7 cm. for the large particles. The local direction of particle flow is determined by calculating the correlation function for sub-regions of 32 x 32 pixels. The velocity vector map is created from this correlation function using the time between images (we use 15 to 30 ms). The software is sensitive variations of 1/64th of a pixel. We produce velocity maps at various heights, each consisting of 3844 velocities. We break this map into three vertical zones for increased height information. The concentration profile is measured using an expanded (1 cm diameter) linearly polarized HeNe Laser incident on the fluidized bed. A COHU camera (gamma=1, AGC off) with a lens and a polarizer images the transmitted linearly polarized light to minimize the effects of multiply scattered light. The intensity profile (640 X 480 pixels) is well described by a Gaussian fit and the height of the Gaussian is used to characterize the concentration. This value is compared to the heights found for known concentrations. The sedimentation velocity is estimated using by imaging a region near the bottom of the bed and using PIV to measure the velocity as a function of time. With a nearly uniform concentration profile, the time can be converted to height information. The stable fluidized beds are made from large pseudo-monodisperse particles (silica spheres with radii (250-300) microns and (425-500) microns) dispersed in a glycerin/water mix. The Peclet number is

  5. FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION

    SciTech Connect

    Jantzen, C

    2006-12-22

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or ''mineralized'' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydroceramics. All but one of the nine monoliths tested met the <2g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydroceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form.

  6. Fluidized Bed Steam Reformer (FBSR) monolith formation

    SciTech Connect

    Jantzen, C.M.

    2007-07-01

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or 'mineralized' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydro-ceramics. All but one of the nine monoliths tested met the <2 g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydro-ceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form. (authors)

  7. Heat and mass transfer in fluidized-bed furnaces in combustion of a coal-water mixture

    NASA Astrophysics Data System (ADS)

    Berg, B. V.; Bogatova, T. F.

    1996-11-01

    The possibility in principle of burning highly ballasted fuel, including irrigated fuel, is considered. The permissible limits of the ash content and the moisture content are determined. The process of the thermal interaction between a drop of a coal-water mixture (CWM) and a fluidized bed is analyzed. Calculations of the distribution of volatiles and moisture in the fluidized bed in one-sided introduction of CWM are performed. The combustion of a CWM in a boiler furnace confirmed the practical possibility and expediency of recovering irrigated fuel waste of coal cleaning by this method.

  8. Fluidized bed gasification of industrial solid recovered fuels.

    PubMed

    Arena, Umberto; Di Gregorio, Fabrizio

    2016-04-01

    The study evaluates the technical feasibility of the fluidized bed gasification of three solid recovered fuels (SRFs), obtained as co-products of a recycling process. The SRFs were pelletized and fed to a pilot scale bubbling fluidized bed reactor, operated in gasification and co-gasification mode. The tests were carried out under conditions of thermal and chemical steady state, with a bed of olivine particles and at different values of equivalence ratio. The results provide a complete syngas characterization, in terms of its heating value and composition (including tars, particulates, and acid/basic pollutants) and of the chemical and physical characterization of bed material and entrained fines collected at the cyclone outlet. The feasibility of the fluidized bed gasification process of the different SRFs was evaluated with the support of a material and substance flow analysis, and a feedstock energy analysis. The results confirm the flexibility of fluidized bed reactor, which makes it one of the preferable technologies for the gasification of different kind of wastes, even in co-gasification mode. The fluidized bed gasification process of the tested SRFs appears technically feasible, yielding a syngas of valuable quality for energy applications in an appropriate plant configuration. PMID:26896004

  9. Fluidized bed gasification of industrial solid recovered fuels.

    PubMed

    Arena, Umberto; Di Gregorio, Fabrizio

    2016-04-01

    The study evaluates the technical feasibility of the fluidized bed gasification of three solid recovered fuels (SRFs), obtained as co-products of a recycling process. The SRFs were pelletized and fed to a pilot scale bubbling fluidized bed reactor, operated in gasification and co-gasification mode. The tests were carried out under conditions of thermal and chemical steady state, with a bed of olivine particles and at different values of equivalence ratio. The results provide a complete syngas characterization, in terms of its heating value and composition (including tars, particulates, and acid/basic pollutants) and of the chemical and physical characterization of bed material and entrained fines collected at the cyclone outlet. The feasibility of the fluidized bed gasification process of the different SRFs was evaluated with the support of a material and substance flow analysis, and a feedstock energy analysis. The results confirm the flexibility of fluidized bed reactor, which makes it one of the preferable technologies for the gasification of different kind of wastes, even in co-gasification mode. The fluidized bed gasification process of the tested SRFs appears technically feasible, yielding a syngas of valuable quality for energy applications in an appropriate plant configuration.

  10. Optimization of Solid Circulation Rate in Compartmented Fluidized Bed Gasifier for Power Generation

    NASA Astrophysics Data System (ADS)

    Chok, V. S.; Wee, S. K.; Ariffin, M. Z. Mohd.; Gorin, A.; Chua, H. B.; Yan, H. M.

    2008-10-01

    The present paper reports the optimization of solid circulation rate (SCR) in Compartmented Fluidized Bed Gasifier (CFBG), an indirectly heated fluidized bed that incorporates two sets of v-valves and risers to control the solid circulation across the two compartments, i.e. combustor and gasifier of a pilot plant scale (the height and ID are 1.8m and 0.66m respectively). Sand was used as inert fluidized by air. Four operating variables were studied i.e. bed height, riser, v-valve and main bed flowrate. Based on 24 full factorial design of experiment in Yates' algorithm, at confidence level ⩾95%, ANOVA analysis has revealed six important effects. The steepest ascent method was applied on linear regression generated from these effects to design the subsequent optimization experiments. The optimum values of SCR have been estimated for both low and high bed level at specific operating parameters.

  11. Analysis of fluidized bed granulation process using conventional and novel modeling techniques.

    PubMed

    Petrović, Jelena; Chansanroj, Krisanin; Meier, Brigitte; Ibrić, Svetlana; Betz, Gabriele

    2011-10-01

    Various modeling techniques have been applied to analyze fluidized-bed granulation process. Influence of various input parameters (product, inlet and outlet air temperature, consumption of liquid-binder, granulation liquid-binder spray rate, spray pressure, drying time) on granulation output properties (granule flow rate, granule size determined using light scattering method and sieve analysis, granules Hausner ratio, porosity and residual moisture) has been assessed. Both conventional and novel modeling techniques were used, such as screening test, multiple regression analysis, self-organizing maps, artificial neural networks, decision trees and rule induction. Diverse testing of developed models (internal and external validation) has been discussed. Good correlation has been obtained between the predicted and the experimental data. It has been shown that nonlinear methods based on artificial intelligence, such as neural networks, are far better in generalization and prediction in comparison to conventional methods. Possibility of usage of SOMs, decision trees and rule induction technique to monitor and optimize fluidized-bed granulation process has also been demonstrated. Obtained findings can serve as guidance to implementation of modeling techniques in fluidized-bed granulation process understanding and control. PMID:21839830

  12. Mechanistic modelling of fluidized bed drying processes of wet porous granules: a review.

    PubMed

    Mortier, Séverine Thérèse F C; De Beer, Thomas; Gernaey, Krist V; Remon, Jean Paul; Vervaet, Chris; Nopens, Ingmar

    2011-10-01

    Fluidized bed dryers are frequently used in industrial applications and also in the pharmaceutical industry. The general incentives to develop mechanistic models for pharmaceutical processes are listed, and our vision on how this can particularly be done for fluidized bed drying processes of wet granules is given. This review provides a basis for future mechanistic model development for the drying process of wet granules in pharmaceutical processes. It is intended for a broad audience with a varying level of knowledge on pharmaceutical processes and mathematical modelling. Mathematical models are powerful tools to gain process insight and eventually develop well-controlled processes. The level of detail embedded in such a model depends on the goal of the model. Several models have therefore been proposed in the literature and are reviewed here. The drying behaviour of one single granule, a porous particle, can be described using the continuum approach, the pore network modelling method and the shrinkage of the diameter of the wet core approach. As several granules dry at a drying rate dependent on the gas temperature, gas velocity, porosity, etc., the moisture content of a batch of granules will reside in a certain interval. Population Balance Model (ling) (PBM) offers a tool to describe the distribution of particle properties which can be of interest for the application. PBM formulation and solution methods are therefore reviewed. In a fluidized bed, the granules show a fluidization pattern depending on the geometry of the gas inlet, the gas velocity, characteristics of the particles, the dryer design, etc. Computational Fluid Dynamics (CFD) allows to model this behaviour. Moreover, turbulence can be modelled using several approaches: Reynolds-averaged Navier-Stokes Equations (RANS) or Large Eddy Simulation (LES). Another important aspect of CFD is the choice between the Eulerian-Lagrangian and the Eulerian-Eulerian approach. Finally, the PBM and CFD frameworks

  13. Hydration of spent limestone and dolomite to enhance sulfation in fluidized-bed combustion

    SciTech Connect

    Shearer, J.A.; Smith, G.W.; Moulton, D.S.; Turner, C.B.; Myles, K.M.; Johnson, I.

    1980-01-01

    The utilization of CaO in fluidized bed combustion can be markedly increased to reduce the cost and environmental impact of quarrying and disposing of large quantities of solid waste. A new method of treatment of spent bed material to reactivate its SO/sub 2/ capturing ability has been found. Partially sulfated spent overflow material from a fluidized-bed combustor is treated with water and then reintroduced to the combustor as renewed feed that further reacts with SO/sub 2/. This material has sufficient physical integrity, due to the outer layer of CaSO/sub 4/, and high reactivity to make it suitable as a sorbent feedstock. The work reported here details observations on a number of limestones and dolomites reacted in laboratory furnaces under simulated combustion conditions as well as verification of the effectiveness of the method in a 15-cm-ID process development unit scale atmospheric fluidized-bed coal combustor. Initial kinetic studies have also been made on the hydration reaction of partially sulfated limestone. A proposed mechanism of interaction is discussed to explain the enhanced reactivity. Changes in total porosity and pore size distribution in the partially sulfated material due to Ca(OH)/sub 2/ formation and its dehydration serve to open up the particle interior and its residual CaO to further reaction with SO/sub 2/. Almost complete utilization of the available CaO can be achieved by successive applications of this promising new technique.

  14. Multistage fluidized bed reactor performance characterization for adsorption of carbon dioxide

    SciTech Connect

    Roy, S.; Mohanty, C.R.; Meikap, B.C.

    2009-12-15

    Carbon dioxide and its different compounds are generated as primary greenhouse gases from the flue gases of coal-fired thermal power plants, boilers, and other stationary combustion processes. This greenhouse gas causes global warming after being emitted to the environment. To deal with this problem, a new dry scrubbing process was tested in this study. A three-stage countercurrent fluidized bed adsorber was developed, designed, and fabricated. It was used as a removal apparatus and operated in a continuous regime for the two-phase system. The height of each stage was 0.30 m, and the inner diameter was 0.10 m. The paper presents the removal of CO{sub 2} from gas mixtures by chemical sorption on porous granular calcium oxide particles in the reactor at ambient temperature. The advantages of a multistage fluidized bed reactor for high mass transfer and high gas-solid contact can enhance the removal of the gas when using a dry method. The effects of the operating parameters such as sorbent, superficial gas velocity, and the Weir height on CO{sub 2} removal efficiency in the multistage fluidized bed were investigated. The results indicate that the removal efficiency of the carbon dioxide was around 71% at a high solid flow rate corresponding to lower gas velocity at room temperature. In comparison with wet scrubbers, this dry process appears to have lower cost, less complicated configuration, and simpler disposal of used sorbent. The results in this study assume importance from the perspective of use of a multistage fluidized bed adsorber for control of gaseous pollutants at high temperature.

  15. Operating experience with a fluidized bed test combustor

    SciTech Connect

    Hainley, D.C.; Haji-Sulaiman, M.Z.; Yavuzkurt, S.; Scaroni, A.W.

    1987-06-01

    This paper presents operating experience with a fluidized bed combustor burning various coals. The primary focus is on the effect of relevant coal properties on combustor performance. Tests were carried out using anthracite, HVB and HVC bituminous and sub-bituminous A coals, and petroleum coke. Comparisons of the performance of the combustion on the various fuels are made. A two-stage fluidized bed combustor operating in a single-stage mode without recycle was employed. Experimental measurements included temperature, fuel feed rate, fluidization velocity and bed height. For some of the coals, bed agglomeration was found to occur. The results indicate that coal properties have an important effect upon the operation of the fluidized bed combustor.

  16. Metallic species derived from fluidized bed coal combustion. [59 references

    SciTech Connect

    Natusch, D.F.S.; Taylor, D.R.

    1980-01-01

    Samples of fly ash generated by the combustion of Montana Rosebud coal in an experimental 18 inch fluidized bed combustor were collected. The use of a heated cascade impactor permitted collection of size fractionated material that avoided condensation of volatile gases on the particles. Elemental concentration trends were determined as a function of size and temperature and the results compared to published reports for conventional power plants. The behavior of trace metals appears to be substantially different in the two systems due to lower operating temperatures and the addition of limestone to the fluidized bed. Corrosion of the impactor plates was observed at the highest temperature and lowest limestone feed rate sampled during the study. Data from the elemental concentration and leaching studies suggest that corrosion is most likely due to reactions involving sodium sulfate. However, it is concluded that corrosion is less of a potential problem in fluidized-bed systems than in conventional coal-fired systems.

  17. Utilizing the fluidized bed to initiate water treatment on site

    SciTech Connect

    Ahmadvand, H.; Germann, G.; Gandee, J.P.; Buehler, V.T.

    1995-12-31

    Escalating wastewater disposal costs coupled with enforcement of stricter regulations push industrial sites previously without water treatment to treat on site. These sites, inexperienced in water treatment, require a treatment technology that is easily installed, operated, and maintained. The aerobic granular activated carbon (GAC) fluidized bed incorporates biological and adsorptive technologies into a simple, cost-effective process capable of meeting strict effluent requirements. Two case studies at industrial sites illustrate the installation and operation of the fluidized bed and emphasize the ability to use the fluidized bed singularly or as an integral component of a treatment system capable of achieving treatment levels that allow surface discharge and reinjection. Attention is focused on BTEX (benzene, toluene, ethylbenzene, and xylenes).

  18. Heat transfer in pressurized circulating fluidized beds

    SciTech Connect

    Wirth, K.E.

    1997-12-31

    The wall-to-suspension heat transfer in circulating fluidized beds (CFBs) operated at almost atmospheric pressure depends on the fluid mechanics immediately near the wall and on the thermal properties of the gas used. No influence of the superficial gas velocity adjusted is present. Consequently, the wall-to-suspension heat transfer coefficient in the form of the Nusselt number can be described by the Archimedes number of the gas-solid-system and the pressure drop number. The last number relates the cross-sectional average solids concentration to the solids concentration at minimum fluidization condition. However, with pressurized CFBs an influence of the superficial gas velocity on the wall-to-suspension heat transfer can be observed. Normalizing the superficial gas velocity in the form of the particle Froude number, two cases for the heat transfer in pressurized CFBs can be detected: with small particle Froude numbers (smaller than four) the same flow behavior and consequently the same heat transfer correlation is valid as it is for CFBs operated at almost atmospheric conditions; and with high particle Froude numbers (for example higher than four) the flow behavior immediately near the heat exchanger surface (CFB wall) can change. Instead of curtains of solids falling down with almost atmospheric pressure swirls of gas and solids can occur in the vicinity of the CFB wall when the static pressure is increased. With the change of the flow pattern near the CFB wall, i.e., the heat exchanger surface, a change of the heat transfer coefficient takes place. For the same Archimedes number, i.e., the same gas-solid system, and the same pressure drop number, i.e., the same cross-sectional average solids concentration, the Nusselt number, i.e., the heat transfer coefficient, increases when the flow pattern near the CFB wall changes from the curtain-type flow to that of the swirl-type flow. From experimentally obtained data in a cold running CFB a very simple correlation was

  19. Computational fluid dynamic modeling of fluidized-bed polymerization reactors

    SciTech Connect

    Rokkam, Ram

    2012-01-01

    Polyethylene is one of the most widely used plastics, and over 60 million tons are produced worldwide every year. Polyethylene is obtained by the catalytic polymerization of ethylene in gas and liquid phase reactors. The gas phase processes are more advantageous, and use fluidized-bed reactors for production of polyethylene. Since they operate so close to the melting point of the polymer, agglomeration is an operational concern in all slurry and gas polymerization processes. Electrostatics and hot spot formation are the main factors that contribute to agglomeration in gas-phase processes. Electrostatic charges in gas phase polymerization fluidized bed reactors are known to influence the bed hydrodynamics, particle elutriation, bubble size, bubble shape etc. Accumulation of electrostatic charges in the fluidized-bed can lead to operational issues. In this work a first-principles electrostatic model is developed and coupled with a multi-fluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the dynamics of a fluidized-bed. The multi-fluid CFD model for gas-particle flow is based on the kinetic theory of granular flows closures. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer, polymer fines) phase. The combined CFD model is first verified using simple test cases, validated with experiments and applied to a pilot-scale polymerization fluidized-bed reactor. The CFD model reproduced qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments. For the scale up of fluidized bed reactor, filtered models are developed and implemented on pilot scale reactor.

  20. Non-intrusive measurement and hydrodynamics characterization of gas-solid fluidized beds: a review

    NASA Astrophysics Data System (ADS)

    Sun, Jingyuan; Yan, Yong

    2016-11-01

    Gas-solid fluidization is a well-established technique to suspend or transport particles and has been applied in a variety of industrial processes. Nevertheless, our knowledge of fluidization hydrodynamics is still limited for the design, scale-up and operation optimization of fluidized bed reactors. It is, therefore, essential to characterize the two-phase flow behaviours in gas-solid fluidized beds and monitor the fluidization processes for control and optimization. A range of non-intrusive techniques have been developed or proposed for measuring the fluidization dynamic parameters and monitoring the flow status without disturbing or distorting the flow fields. This paper presents a comprehensive review of the non-intrusive measurement techniques and the current state of knowledge and experience in the characterization and monitoring of gas-solid fluidized beds. These techniques are classified into six main categories as per sensing principles, electrostatic, acoustic emission and vibration, visualization, particle tracking, laser Doppler anemometry and phase Doppler anemometry as well as pressure-fluctuation methods. Trends and future developments in this field are also discussed.

  1. Monitoring granulation rate processes using three PAT tools in a pilot-scale fluidized bed.

    PubMed

    Tok, Ai Tee; Goh, Xueping; Ng, Wai Kiong; Tan, Reginald B H

    2008-01-01

    The purpose of this research was to analyze and compare the responses of three Process Analytical Technology (PAT) techniques applied simultaneously to monitor a pilot-scale fluidized bed granulation process. Real-time measurements using focused beam reflectance measurement (Lasentec FBRM) and near-infra red spectroscopy (Bruker NIR) were taken by inserting in-line probes into the fluidized bed. Non-intrusive acoustic emission measurements (Physical Acoustic AE) were performed by attaching piezoelectric sensors on the external wall of the fluidized bed. Powder samples were collected at regular intervals during the granulation process and characterized offline using laser diffraction, scanning electron microscopy, stereo-optical microscopy and loss on drying method. PAT data comprising chord length distribution and chord count (from FBRM), absorption spectra (from NIR) and average signal levels and counts (from AE) were compared with the particle properties measured using offline samples. All three PAT techniques were able to detect the three granulation regimes or rate processes (wetting and nucleation, consolidation and growth, breakage) to varying degrees of sensitivity. Being dependent on optical signals, the sensitivities of the FBRM and NIR techniques were susceptible to fouling on probe windows. The AE technique was sensitive to background fluidizing air flows and external interferences. The sensitivity, strengths and weaknesses of the PAT techniques examined may facilitate the selection of suitable PAT tools for process development and scale-up studies.

  2. Coal-feeding mechanism for a fluidized bed combustion chamber

    SciTech Connect

    Gall, R. L.

    1981-06-02

    The present invention is directed to a fuel-feeding mechanism for a fluidized bed combustor. In accordance with the present invention a perforated conveyor belt is utilized in place of the fixed grid normally disposed at the lower end of the fluidized bed combustion zone. The conveyor belt is fed with fuel, E.G. Coal, at one end thereof so that the air passing through the perforations dislodges the coal from the belt and feeds the coal into the fluidized zone in a substantially uniform manner.

  3. Review of ash agglomeration in fluidized bed gasifiers

    SciTech Connect

    Matulevicius, E.S.; Golan, L.P.

    1984-07-01

    The purpose of this study is to review the data and mathematical models which describe the phenomena involved in the agglomeration of ash in fluidized bed coal gasifiers (FBG). Besides highlighting the data and theoretical models, this review lists areas where there is a lack of information regarding the actual mechanisms of agglomeration. Also, potential areas for further work are outlined. The work is directed at developing models of agglomeration which could be included in computer codes describing fluidized bed gasifier phenomena, e.g., FLAG and CHEMFLUB which have been developed for the US Department of Energy. 134 references, 24 figures, 13 tables.

  4. Fluidized-Bed Deposition Of Single-Crystal Silicon

    NASA Technical Reports Server (NTRS)

    Hsu, George C.; Rohatgi, Naresh K.

    1988-01-01

    Uniformly thin single-crystal films of silicon produced by modification of fluidized-bed-reactor technique producing polysilicon by chemical vapor deposition. Proposed for silicon wafers for flat-plate solar arrays and results in different structural and electronic properties in deposition layer desirable for specific microelectronic or solar-cell processing. In process deposition occurs on silicon wafers, kept individually at temperatures above 1,000 degree C. Heated wafers held in unheated and minimally-agitated-fluidized bed of silicon particles and in low concentration of silane.

  5. Internal dust recirculation system for a fluidized bed heat exchanger

    DOEpatents

    Gamble, Robert L.; Garcia-Mallol, Juan A.

    1981-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

  6. Pressurized fluidized-bed combustion technology exchange workshop

    SciTech Connect

    ,

    1980-04-01

    The pressurized fluidized-bed combustion technology exchange workshop was held June 5 and 6, 1979, at The Meadowlands Hilton Hotel, Secaucus, New Jersey. Eleven papers have been entered individually into EDB and ERA. The papers include reviews of the US DOE and EPRI programs in this area and papers by Swedish, West German, British and American organizations. The British papers concern the joint program of the USA, UK and FRG at Leatherhead. The key factor in several papers is the use of fluidized bed combustors, gas turbines, and steam turbines in combined-cycle power plants. One paper examines several combined-cycle alternatives. (LTN)

  7. Refractory experience in circulating fluidized bed combustors, Task 7

    SciTech Connect

    Vincent, R.Q.

    1989-11-01

    This report describes the results of an investigation into the status of the design and selection of refractory materials for coal-fueled circulating fluidized-bed combustors. The survey concentrated on operating units in the United States manufactured by six different boiler vendors: Babcock and Wilcox, Combustion Engineering, Foster Wheeler, Keeler Dorr-Oliver, Pyropower, and Riley Stoker. Information was obtained from the boiler vendors, refractory suppliers and installers, and the owners/operators of over forty units. This work is in support of DOE's Clean Coal Technology program, which includes circulating fluidized-bed technology as one of the selected concepts being evaluated.

  8. Coal-feeding mechanism for a fluidized bed combustion chamber

    DOEpatents

    Gall, Robert L.

    1981-01-01

    The present invention is directed to a fuel-feeding mechanism for a fluidized bed combustor. In accordance with the present invention a perforated conveyor belt is utilized in place of the fixed grid normally disposed at the lower end of the fluidized bed combustion zone. The conveyor belt is fed with fuel, e.g. coal, at one end thereof so that the air passing through the perforations dislodges the coal from the belt and feeds the coal into the fluidized zone in a substantially uniform manner.

  9. Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes

    DOEpatents

    Talmud, Fred M.; Garcia-Mallol, Juan-Antonio

    1980-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to a water drum and in the path of the air and the gaseous products of combustion exiting from the bed. Another portion of the tubes pass through the bed and extend at an angle to the upper surface of the bed.

  10. Regeneration of lime from sulfates for fluidized-bed combustion

    DOEpatents

    Yang, Ralph T.; Steinberg, Meyer

    1980-01-01

    In a fluidized-bed combustor the evolving sulfur oxides are reacted with CaO to form calcium sulfate which is then decomposed in the presence of carbonaceous material, such as the fly ash recovered from the combustion, at temperatures of about 900.degree. to 1000.degree. C., to regenerate lime. The regenerated lime is then recycled to the fluidized bed combustor to further react with the evolving sulfur oxides. The lime regenerated in this manner is quite effective in removing the sulfur oxides.

  11. PMB-Waste: An analysis of fluidized bed thermal treatment

    SciTech Connect

    Gat, U.; Kass, M.D.; Lloyd, D.B.

    1995-07-01

    A fluidized bed treatment process was evaluated for solid waste from plastic media blasting of aircraft protective coating. The treatment objective is to decompose and oxidize all organic components, and concentrate all the hazardous metals in the ash. The reduced volume and mass are expected to reduce disposal cost. A pilot test treatment was done in an existing fluidized bed equipped with emissions monitors, and emissions within regulatory requirements were demonstrated. A economic analysis of the process is inconclusive due to lack of reliable cost data of disposal without thermal treatment.

  12. Feasibility study on pliant media drying using fluidized bed dryer

    NASA Astrophysics Data System (ADS)

    Zakaria, J. H.; Zaid, M. H. H. M.; Batcha, M. F. M.; Asmuin, N.

    2015-09-01

    The usage of pliant media for blasting in surface preparation has gained substantial interest in various industries, particularly oil and gas. Being a clean technology, this relatively new method of surface preparation has become an alternative to conventional abrasive blasting technique which lowers fugitive emissions from blasting process and hence lowering risk to workers in the industry. Despite proven to be effective and cost efficient, the usage of pliant media in tropical climate poses a new challenge due to the torrential rain in the monsoon season. During rainy and wet conditions, the pliant media was literally soaked and the recovery rate of the pliant media for a continuous blasting becomes retarded. A viable technique for drying of this pliant media has then become imperative. The present study proposes to dry water laden pliant media in a Swirling Fluidized Bed Dryer (SFBD). In this preliminary study, three bed loadings of 1.7, 2.0 and 2.3 kg of pliant media was dried in the SfBd at 80°C, 90°C and 100°C. The experimental works revealed that the SFBD has shown excellent potential to dry the pliant media with a relatively short drying time. The behaviour of moisture ratio and drying rate against time are discussed. The findings conclude that the SFBD is a feasible technique for wet pliant media drying and can be extended for continuous processing system.

  13. Fluidized bed layer-by-layer microcapsule formation.

    PubMed

    Richardson, Joseph J; Teng, Darwin; Björnmalm, Mattias; Gunawan, Sylvia T; Guo, Junling; Cui, Jiwei; Franks, George V; Caruso, Frank

    2014-08-26

    Polymer microcapsules can be used as bioreactors and artificial cells; however, preparation methods for cell-like microcapsules are typically time-consuming, low yielding, and/or involve custom microfluidics. Here, we introduce a rapid (∼30 min per batch, eight layers), scalable (up to 500 mg of templates), and efficient (98% yield) microcapsule preparation technique utilizing a fluidized bed for the layer-by-layer (LbL) assembly of polymers, and we investigate the parameters that govern the formation of robust capsules. Fluidization in water was possible for particles of comparable diameter to mammalian cells (>5 μm), with the experimental flow rates necessary for fluidization matching well with the theoretical values. Important variables for polymer film deposition and capsule formation were the concentration of polymer solution and the molecular weight of the polymer, while the volume of the polymer solution had a negligible impact. In combination, increasing the polymer molecular weight and polymer solution concentration resulted in improved film deposition and the formation of robust microcapsules. The resultant polymer microcapsules had a thickness of ∼5.5 nm per bilayer, which is in close agreement with conventionally prepared (quiescent (nonflow) adsorption/centrifugation/wash) LbL capsules. The technique reported herein provides a new way to rapidly generate microcapsules (approximately 8 times quicker than the conventional means), while being also amenable to scale-up and mass production. PMID:25113552

  14. Inductive classification of operating data from a fluidized bed calciner

    SciTech Connect

    O`Brien, B H

    1990-05-30

    A process flowsheet expert system for a fluidized bed calciner which solidifies high-level radioactive liquid waste was developed from pilot-plant data using a commercial, inductive classification program. After initial classification of the data, the resulting rules were inspected and adjusted to match existing knowledge of process chemistry. The final expert system predicts performance of process flowsheets based upon the chemical composition of the calciner feed and has been successfully used to identify potential operational problems prior to calciner pilot-plant testing of new flowsheets and to provide starting parameters for pilot-plant tests. By using inductive classification techniques to develop the initial rules from the calciner pilot-plant data and using existing process knowledge to verify the accuracy of these rules, an effective expert system was developed with a minimum amount of effort. This method may be applied for developing expert systems for other processes where numerous operating data are available and only general process chemistry effects are known.

  15. Product quality multi-objective optimization of fluidized bed dryers

    SciTech Connect

    Krokida, M.K.; Kiranoudis, C.T.

    2000-01-01

    Design of fluidized bed dryers constitutes a mathematical programming problem involving the evaluation of appropriate structural and operational process variables so that total annual plant cost involved is optimized. The increasing need for dehydrated products of the highest quality, imposes the development of new criteria that, together with cost, determine the design rules for drying processes. Quality of dehydrated products is a complex resultant of properties characterizing the final products, where the most important one is color. Color is determined as a three-parameter resultant, whose values for products undergone drying should deviate from the corresponding ones of natural products, as little as possible. In this case, product quality dryer design is a complex multi-objective optimization problem, involving the color deviation vector as an objective function and as constraints the ones deriving from the process mathematical model. The mathematical model of the dryer was developed and the fundamental color deterioration laws were determined for the drying process. Non-preference multi-criteria optimization methods were used and the Pareto-optimal set of efficient solutions was evaluated. An example covering the drying of sliced potato was included to demonstrate the performance of the design procedure, as well as the effectiveness of the proposed approach.

  16. Fluidized bed layer-by-layer microcapsule formation.

    PubMed

    Richardson, Joseph J; Teng, Darwin; Björnmalm, Mattias; Gunawan, Sylvia T; Guo, Junling; Cui, Jiwei; Franks, George V; Caruso, Frank

    2014-08-26

    Polymer microcapsules can be used as bioreactors and artificial cells; however, preparation methods for cell-like microcapsules are typically time-consuming, low yielding, and/or involve custom microfluidics. Here, we introduce a rapid (∼30 min per batch, eight layers), scalable (up to 500 mg of templates), and efficient (98% yield) microcapsule preparation technique utilizing a fluidized bed for the layer-by-layer (LbL) assembly of polymers, and we investigate the parameters that govern the formation of robust capsules. Fluidization in water was possible for particles of comparable diameter to mammalian cells (>5 μm), with the experimental flow rates necessary for fluidization matching well with the theoretical values. Important variables for polymer film deposition and capsule formation were the concentration of polymer solution and the molecular weight of the polymer, while the volume of the polymer solution had a negligible impact. In combination, increasing the polymer molecular weight and polymer solution concentration resulted in improved film deposition and the formation of robust microcapsules. The resultant polymer microcapsules had a thickness of ∼5.5 nm per bilayer, which is in close agreement with conventionally prepared (quiescent (nonflow) adsorption/centrifugation/wash) LbL capsules. The technique reported herein provides a new way to rapidly generate microcapsules (approximately 8 times quicker than the conventional means), while being also amenable to scale-up and mass production.

  17. Performance and electrochemical behavior of fluidized bed electrodes

    SciTech Connect

    Huh, T.

    1985-01-01

    The fluidized bed electrode was studied to characterize its behavior and evaluate its possible application to the electrowinning of precious metals and to the energy storage systems. Its performance and electrochemical behavior were analyzed in terms of various operating parameters. The first part of the study is concerned mainly with the overall performance of a fluidized-bed electrode for silver recovery from aqueous cyanide solution. The effects of applied current density, bed expansion, and electrode materials were considered, and its was found that the performance is free of operating problems and is superior to the Azadra-type cell, which is commonly used for precious metal recovery. The second part is concerned with the internal behavior of the fluidized bed electrode. The particle and electrolyte potentials and overpotentials in fluidized bed electrodes of two different types have been measured and analyzed by means of the probability density distribution and the power spectral density distribution. The resistance of such electrodes are also measured. The potential transients are observed to depend on current, bed expansion, and position in the bed (for copper particles) and each potential can be regarded as a time averaged value onto which two kinds of noise, low-frequency flicker noise and white noise, are added.

  18. Heat exchanger support apparatus in a fluidized bed

    DOEpatents

    Lawton, Carl W.

    1982-01-01

    A heat exchanger is mounted in the upper portion of a fluidized combusting bed for the control of the temperature of the bed. A support, made up of tubes, is extended from the perforated plate of the fluidized bed up to the heat exchanger. The tubular support framework for the heat exchanger has liquid circulated therethrough to prevent deterioration of the support.

  19. Fluidized bed combustor and coal gun-tube assembly therefor

    DOEpatents

    Hosek, William S.; Garruto, Edward J.

    1984-01-01

    A coal supply gun assembly for a fluidized bed combustor which includes heat exchange elements extending above the bed's distributor plate assembly and in which the gun's nozzles are disposed relative to the heat exchange elements to only discharge granular coal material between adjacent heat exchange elements and in a path which is substantially equidistant from adjacent heat exchange elements.

  20. Computational and Experimental Studies of Fluidized Beds for Biomass Gasification

    NASA Astrophysics Data System (ADS)

    Battaglia, Francine; Deza, Mirka; Franka, Nathan; Heindel, Theodore

    2007-11-01

    Fluidized bed gasifiers can convert feedstocks with low-carbon content into valuable products such as ethanol. Understanding fluidized bed hydrodynamics is important for reactor design and avoiding issues such as agglomeration or defluidization of the bed. In particular, biomass gasification is not well characterized and is the focus of this work. Glass beads or sand particles are typically used as bed materials due to their high sphericity and uniform properties. X-ray imaging will be used to visualize these complex flows and alternative bed materials will be considered to increase X-ray penetration and resolution to enhance flow visualization. Furthermore, computational modeling of fluidized beds can be used to predict operation of biomass gasifiers after extensive validation with experimental data. The hydrodynamics will be modeled assuming each phase behaves as interpenetrating continua using an Eulerian model and each solid phase is characterized by a particle diameter and density so that segregation and elutriation can be described. The simulations will model the cold-flow fluidized bed experiment, and consider factors such as sphericity of the particles, and calibration of drag coefficients. Hydrodynamic results from the simulations will be qualitatively and quantitatively compared to X-ray flow visualization studies of a similar bed.

  1. A fluidized-bed reactor for silane pyrolysis

    NASA Technical Reports Server (NTRS)

    Iya, S.

    1984-01-01

    The silane decomposition in a fluidized bed reactor was studied. The process feasibility and operating windows were determined. Long duration tests were conducted and silicon purity was demonstrated. A high purity linear was installed in the fluid bed reactor; the FBR product was melted and single crystallized. Product purity improvements are noted.

  2. Description of emission control using fluidized-bed, heat-exchange technology

    SciTech Connect

    Vogel, G.J.; Grogan, P.J.

    1980-06-01

    Environmental effects of fluidized-bed, waste-heat recovery technology are identified. The report focuses on a particular configuration of fluidized-bed, heat-exchange technology for a hypothetical industrial application. The application is a lead smelter where a fluidized-bed, waste-heat boiler (FBWHB) is used to control environmental pollutants and to produce steam for process use. Basic thermodynamic and kinetic information for the major sulfur dioxide (SO/sub 2/) and NO/sub x/ removal processes is presented and their application to fluidized-bed, waste heat recovery technology is discussed. Particulate control in fluidized-bed heat exchangers is also discussed.

  3. Factors influencing the nitrification efficiency of fluidized bed filter with a plastic bead medium

    USGS Publications Warehouse

    Sandu, S.I.; Boardman, G.D.; Watten, B.J.; Brazil, B.L.

    2002-01-01

    The performance of fluidized bed nitrification filters charged with 2 ?? 4 ABS plastic beads (specific gravity 1.06) was evaluated. Three unique bed-height to diameter ratios were established, in triplicate, using column diameters of 12.7, 15.2 and 17.8 cm. Filters received water spiked with recycled nutrients and ammonia (TAN), from one of the three 500 1 feed tank system. With daily ammonia loading fixed at 8.6 g per system, TAN removal increased with column diameter at each of four tests hydraulic loading rates (6, 8, 10 and 12 Lpm). TAN in recirculated water (influent) rose from 0.5 to 1.0 mg/1 as ammonia loading increased from 180 mg/m2-day to 360 mg/m2-day. When hydraulic loading was fixed at 12 Lpm, TAN removal (%) was maximized with ammonia loadings ranging from 225 to 270 mg/m2-day. Biofilm thickness increased with ammonia loading, but decreased with increased hydraulic loading rates. Fluidized beds of ABS plastic beads were effective in reducing energy costs (head loss) of water treatment. ?? 2002 Elsevier Science B.V. All rights reserved.

  4. Accelerated Weathering of Fluidized Bed Steam Reformation Material Under Hydraulically Unsaturated Conditions

    SciTech Connect

    Pierce, Eric M.

    2007-09-16

    To predict the long-term fate of low- and high-level waste forms in the subsurface over geologic time scales, it is important to understand the behavior of the corroding waste forms under conditions the mimic to the open flow and transport properties of a subsurface repository. Fluidized bed steam reformation (FBSR), a supplemental treatment technology option, is being considered as a waste form for the immobilization of low-activity tank waste. To obtain the fundamental information needed to evaluate the behavior of the FBSR waste form under repository relevant conditions and to monitor the long-term behavior of this material, an accelerated weathering experiment is being conducted with the pressurized unsaturated flow (PUF) apparatus. Unlike other accelerated weathering test methods (product consistency test, vapor hydration test, and drip test), PUF experiments are conducted under hydraulically unsaturated conditions. These experiments are unique because they mimic the vadose zone environment and allow the corroding waste form to achieve its final reaction state. Results from this on-going experiment suggest the volumetric water content varied as a function of time and reached steady state after 160 days of testing. Unlike the volumetric water content, periodic excursions in the solution pH and electrical conductivity have been occurring consistently during the test. Release of elements from the column illustrates a general trend of decreasing concentration with increasing reaction time. Normalized concentrations of K, Na, P, Re (a chemical analogue for 99Tc), and S are as much as 1 × 104 times greater than Al, Cr, Si, and Ti. After more than 600 days of testing, the solution chemistry data collected to-date illustrate the importance of understanding the long-term behavior of the FBSR product under conditions that mimic the open flow and transport properties of a subsurface repository.

  5. Element associations in ash from waste combustion in fluidized bed

    SciTech Connect

    Karlfeldt Fedje, K.; Rauch, S.; Cho, P.; Steenari, B.-M.

    2010-07-15

    The incineration of MSW in fluidized beds is a commonly applied waste management practice. The composition of the ashes produced in a fluidized bed boiler has important environmental implications as potentially toxic trace elements may be associated with ash particles and it is therefore essential to determine the mechanisms controlling the association of trace elements to ash particles, including the role of major element composition. The research presented here uses micro-analytical techniques to study the distribution of major and trace elements and determine the importance of affinity-based binding mechanisms in separate cyclone ash particles from MSW combustion. Particle size and the occurrence of Ca and Fe were found to be important factors for the binding of trace elements to ash particles, but the binding largely depends on random associations based on the presence of a particle when trace elements condensate in the flue gas.

  6. Fluidized bed combustor and removable windbox and tube assembly therefor

    DOEpatents

    DeFeo, Angelo; Hosek, William

    1983-01-01

    A fluidized bed combustor comprises a housing having a chamber therein with a top having a discharge for the gases which are generated in the chamber and a bottom with a discharge for heated fluid. An assembly is arranged in the lower portion of the chamber and the assembly includes a lower plate which is mounted on a support flange of the housing so that it is spaced from the bottom of the chamber and defines a fluid plenum between it and the bottom of the chamber for the discharge of heated fluid. The assembly includes a heat exchanger inlet plenum having tubes therethrough for the passage of fluidizer air and a windbox above the heat exchanger plenum which has a distributor plate top wall. A portion of the chamber above the top wall defines a fluidized bed.

  7. Fluidized bed combustor and removable windbox and tube assembly therefor

    DOEpatents

    DeFeo, Angelo; Hosek, William S.

    1981-01-01

    A fluidized bed combustor comprises a housing having a chamber therein with a top having a discharge for the gases which are generated in the chamber and a bottom with a discharge for heated fluid. An assembly is arranged in the lower portion of the chamber and the assembly includes a lower plate which is mounted on a support flange of the housing so that it is spaced from the bottom of the chamber and defines a fluid plenum between it and the bottom of the chamber for the discharge of heated fluid. The assembly includes a heat exchanger inlet plenum having tubes therethrough for the passage of fluidizer air and a windbox above the heat exchanger plenum which has a distributor plate top wall. A portion of the chamber above the top wall defines a fluidized bed.

  8. Decontamination of combustion gases in fluidized bed incinerators

    DOEpatents

    Leon, Albert M.

    1982-01-01

    Sulfur-containing atmospheric pollutants are effectively removed from exit gas streams produced in a fluidized bed combustion system by providing a fluidized bed of particulate material, i.e. limestone and/or dolomite wherein a concentration gradient is maintained in the vertical direction. Countercurrent contacting between upwardly directed sulfur containing combustion gases and descending sorbent particulate material creates a concentration gradient across the vertical extent of the bed characterized in progressively decreasing concentration of sulfur, sulfur dioxide and like contaminants upwardly and decreasing concentration of e.g. calcium oxide, downwardly. In this manner, gases having progressively decreasing sulfur contents contact correspondingly atmospheres having progressively increasing concentrations of calcium oxide thus assuring optimum sulfur removal.

  9. Torrefaction of sawdust in a fluidized bed reactor.

    PubMed

    Li, Hui; Liu, Xinhua; Legros, Robert; Bi, Xiaotao T; Lim, C J; Sokhansanj, Shahab

    2012-01-01

    In the present work, stable fluidization of sawdust was achieved in a bench fluidized bed with an inclined orifice distributor without inert bed materials. A solids circulation pattern was established in the bed without the presence of slugging and channeling. The effects of treatment severity and weight loss on the solid product properties were identified. The decomposition of hemicelluloses was found to be responsible for the significant changes of chemical, physical and mechanical properties of the torrefied sawdust, including energy content, particle size distribution and moisture absorption capacity. The hydrophobicity of the torrefied sawdust was improved over the raw sawdust with a reduction of around 40 wt.% in saturated water uptake rate, and enhanced with increasing the treatment severity due to the decomposition of hemicelluloses which are rich in hydroxyl groups. The results in this study provided the basis for torrefaction in fluidized bed reactors.

  10. Fluidized bed combustion offers replacement option for old boilers

    SciTech Connect

    1997-01-01

    As emission standards begin to tighten and existing boilers grow older, electric utilities are searching for cost-effective and environmentally sound replacements for aging boilers. In the past few years, fluidized bed combustion (FBC) has emerged as a viable replacement option for old, conventional boilers. The results of three case studies involving conversion of existing boilers to FBC are discussed in this paper. 1 ref., 3 tabs.

  11. Bed drain cover assembly for a fluidized bed

    DOEpatents

    Comparato, Joseph R.; Jacobs, Martin

    1982-01-01

    A loose fitting movable cover plate (36), suitable for the severe service encountered in a fluidized bed combustor (10), restricts the flow of solids into the combustor drain lines (30) during shutdown of the bed. This cover makes it possible to empty spent solids from the bed drain lines which would otherwise plug the piping between the drain and the downstream metering device. This enables use of multiple drain lines each with a separate metering device for the control of solids flow rate.

  12. Placing bigger bets on fluidized-bed boilers

    SciTech Connect

    Not Available

    1984-10-17

    The situation in the US where second-generation fluidized-bed technology is being introduced by manufacturers is described. Examples of the circulating bed and multiple bed are given. Installations of first-generation bubbling bed are quoted. The advantages of fluidised-bed combustion in terms of efficiency, ability to burn low-cost, high-sulphur coals, and low emissions are cited.

  13. An option for aging boilers-fluidized bed combustion

    SciTech Connect

    Epelbaum, G.; Friedrich, J.L.

    1995-12-31

    Fossil fuel fired steam generators designed and built prior to 1970 generally incorporated a particulate reduction system as the sole emission control. This is because other gaseous and solid emissions were not a significant issue during the 50s and 60s. There are several trends that these boilers and the industry have experienced since then: (1) boilers have aged and their pressure parts and auxiliary equipment condition has deteriorated; (2) increased commercial competition calls for fuel flexibility, optimum performance, reliability and maintenance; (3) solid fuel quality has been deteriorating, gas and oil market and availability are volatile; (4) environmental awareness has risen dramatically, thus requiring more stringent and more comprehensive emission requirements that the operating boilers must comply with; (5) new combustion technologies have been developed. At the same time, the existing turbine generator equipment, if reasonably maintained, is capable of providing competitive and reliable electrical power production. Different approaches can be taken to provide a new steam generating source for the existing turbine cycle retirement of old boilers and building new ones; boiler modification and switching to different fuels and technologies boiler modernization and addition of emission control equipment (such as low-NOx burner, SCR, SNCR, FGD, etc.) This paper addresses an alternative solution: conversion of conventional boilers to fluidized bed technology. Foster Wheeler Energy Corporation (FWEC), which successfully competes worldwide with the two proven technologies (conventional boilers and fluidized bed), has accumulated substantial on-site experience indicating that the fluidized-bed option can provide a significant cost/benefit advantage. This article presents several site specific examples to demonstrate a FWEC approach to the fluidized bed conversion and its advantages.

  14. Pulsed atmospheric fluidized bed combustor apparatus and process

    DOEpatents

    Mansour, Momtaz N.

    1992-01-01

    A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g. organic and medical waste, drying, calcining and the like.

  15. Fluidized bed gasification ash reduction and removal system

    DOEpatents

    Schenone, Carl E.; Rosinski, Joseph

    1984-02-28

    In a fluidized bed gasification system an ash removal system to reduce the particulate ash to a maximum size or smaller, allow the ash to cool to a temperature lower than the gasifier and remove the ash from the gasifier system. The system consists of a crusher, a container containing level probes and a means for controlling the rotational speed of the crusher based on the level of ash within the container.

  16. Fluidized bed gasification ash reduction and removal process

    DOEpatents

    Schenone, Carl E.; Rosinski, Joseph

    1984-12-04

    In a fluidized bed gasification system an ash removal system to reduce the particulate ash to a maximum size or smaller, allow the ash to cool to a temperature lower than the gasifier and remove the ash from the gasifier system. The system consists of a crusher, a container containing level probes and a means for controlling the rotational speed of the crusher based on the level of ash within the container.

  17. Inclined fluidized bed system for drying fine coal

    DOEpatents

    Cha, Chang Y.; Merriam, Norman W.; Boysen, John E.

    1992-02-11

    Coal is processed in an inclined fluidized bed dryer operated in a plug-flow manner with zonal temperature and composition control, and an inert fluidizing gas, such as carbon dioxide or combustion gas. Recycled carbon dioxide, which is used for drying, pyrolysis, quenching, and cooling, is produced by partial decarboxylation of the coal. The coal is heated sufficiently to mobilize coal tar by further pyrolysis, which seals micropores upon quenching. Further cooling with carbon dioxide enhances stabilization.

  18. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project. 1990 Annual report

    SciTech Connect

    Not Available

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  19. Fluidized bed silicon deposition. [Si production via silane pyrolysis

    NASA Technical Reports Server (NTRS)

    Hsu, G.; Morrison, A.; Rohatgi, N.; Lutwack, R.; Macconnell, T.

    1984-01-01

    The growth of silicon on seed particles from the pyrolysis of silane in a fluidized bed reactor (FBR) was studied. The grown particles were shown to be crystalline and to have a structure which has been interpreted to indicate growth by chemical vapor deposition as well as by the collection (scavenging) of silicon clusters on seed particle surfaces. Scanning electron microscopy was used to study the product morphology.

  20. Mathematical model for the continuous combustion of char particles in a fluidized bed

    SciTech Connect

    Saxena, S.C.; Rehmat, A.

    1980-12-01

    Recently, we have developed the direct oxidation model for the combustion of a batch of char in a fluidized bed. This analysis is extended for the continuous combustion of char, and a system of general equations has been derived to relate the feed rate of char to the amount of char particles present in the fluidized bed and in the overflow stream. The size distribution of char particles and their number in the bed are also predicted. The analysis indicates that the amount of carbon present in the bed is independent of the feed particle size at fixed values of the char feed rate and fluidizing-gas velocity although the number of char bed particles depends upon the feed particle size. Further, the carbon content of the bed and the number of char particles in the bed are found to depend heavily on the char feed rate and the fluidizing-gas velocity. A discrete cut method is described whereby the particle size distribution and the number of particles present in the bed are calculated. The method provides a simplified trial-and-error procedure for those cases in which the rate of change in particle size is a complex nonintegrable function of the particle size. The discrete cut method is found to yield results which are in good agreement with the exact solutions of the integrals defining the number of particles and their size distribution. The model provides a simple base for the scale-up and design work related to fluidized-bed coal combustors.

  1. Erosion of heat exchanger tubes in fluidized beds

    SciTech Connect

    Johnson, E.K.; Flemmer, R.L.C.

    1991-01-01

    This final report describes the activities of the 3-year project entitled Erosion of Heat Exchanger Tubes In Fluidized Beds.'' which was completed at the end of 1990. Project accomplishments include the collection of a substantial body of wear data In a 24in. [times] 24in. fluidized bed, comparative wear results In a 6in. [times] 6in. fluidized bed, the development of a dragometer and the collection of a comprehensive set of drag force data in the 24in. [times] 24in. bed, Fast Fourier Transform (FFT) analysis of bubble probe data to establish dominant bubble frequencies in the 24in. [times] 24in. bed, the use of a heat flux gauge for measurement of heat transfer coefficients in the 24in. [times] 24in. bed and the modeling of the tube wear in the 24in. [times] 24in. bed. Analysis of the wear data from the 24in. square bed indicates that tube wear increases with increase in superficial velocity, and with increase in tube height. The latter effect is a result of the tubes higher up in the bed seeing greater movement of dense phase than tubes lower down In the bed. In addition, tube wear was found to decrease with increase in particle size, for constant superficial velocity. Three models of tube wear were formulated and provided acceptable prediction of wear when compared with the experimental data.

  2. Pulsed atmospheric fluidized-bed combustor development. Environmental Assessment

    SciTech Connect

    Not Available

    1992-05-01

    Pulsed atmospheric fluidized-bed combustion (PAFBC) is a unique and innovative coal-fueled technology that has the potential to meet these conditions and provide heat and/or process steam to small industrial, commercial, institutional and residential complexes. The potential of Pulse Atmospheric Fluidized Bed Combustion (PAFBC) technology has been amply demonstrated under the sponsorship of a previous DOE/METC contract (DE-AC21-88MC25069). The environmental performance of a coal-fired laboratory-scale system (1.5 million British Thermal Units per hour) (MMBtu/hr) significantly surpassed that of conventional bubbling and circulating fluidized-bed combustion units (see Table 1 for performance comparison). Prompted by these encouraging results in combustion, sulfur capture, emissions control, and enhanced heat transfer, Island Creek Coal Company (ICC) and Baltimore Thermal Energy Corporation expressed interest in the technology and offered to participate by providing host sites for field testing. EA`s have been submitted independently for each of these field test sites. This submission addresses the preliminary testing of the PAFBC unit at Manufacturing and Technology Conversion International`s (MTCI) Baltimore, MD facility.

  3. Numerical Study of Pyrolysis of Biomass in Fluidized Beds

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Lathouwers, Danny

    2003-01-01

    A report presents a numerical-simulation study of pyrolysis of biomass in fluidized-bed reactors, performed by use of the mathematical model described in Model of Fluidized Bed Containing Reacting Solids and Gases (NPO-30163), which appears elsewhere in this issue of NASA Tech Briefs. The purpose of the study was to investigate the effect of various operating conditions on the efficiency of production of condensable tar from biomass. The numerical results indicate that for a fixed particle size, the fluidizing-gas temperature is the foremost parameter that affects the tar yield. For the range of fluidizing-gas temperatures investigated, and under the assumption that the pyrolysis rate exceeds the feed rate, the optimum steady-state tar collection was found to occur at 750 K. In cases in which the assumption was not valid, the optimum temperature for tar collection was found to be only slightly higher. Scaling up of the reactor was found to exert a small negative effect on tar collection at the optimal operating temperature. It is also found that slightly better scaling is obtained by use of shallower fluidized beds with greater fluidization velocities.

  4. A staged fluidized-bed comubstion and filter system

    SciTech Connect

    Mei, J.S.; Halow, J.S.

    1993-12-31

    A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized- bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gasses into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste.

  5. An option for aging boilers -- Fluidized bed combustion

    SciTech Connect

    Epelbaum, G.; Friedrich, J.L.

    1996-12-31

    Fossil fuel fired steam generators designed and built prior to 1970 generally incorporated a particulate reduction system as the sole emission control. This is because other gaseous and solid emissions were not a significant issue during the 50s and 60s. There are several trends that these boilers and the industry have experienced since then: boilers have aged and their pressure parts and auxiliary equipment condition has deteriorated; increased commercial competition calls for fuel flexibility, optimum performance, reliability and maintenance; solid fuel quality has been deteriorating, gas and oil market and availability are volatile; environmental awareness has risen dramatically, thus requiring more stringent and more comprehensive emission requirements that the operating boilers must comply with; a new combustion technologies have been developed. At the same time, the existing turbine generator equipment, if reasonably maintained, is capable of providing competitive and reliable electrical power production. Different approaches can be taken to provide a new steam generating source for the existing turbine cycle: retirement of old boilers and building new ones; boiler modification and switching to different fuels and technologies; boiler modernization and addition of emission control equipment (such as low-NO{sub x} burner, SCR, SNCR, FGD, etc.). This paper addresses an alternative solution: conversion of conventional boilers to fluidized bed technology. Foster Wheeler Energy Corporation (FWEC), which successfully competes worldwide with the two proven technologies (conventional boilers and fluidized bed), has accumulated substantial on-site experience indicating that the fluidized-bed option can provide a significant cost/benefit advantage.

  6. Physicochemical characterizations of limestone for fluidized-bed coal combustion

    SciTech Connect

    Fuller, E.L. Jr.; Yoos, T.R. III; Walia, D.S.

    1981-05-01

    This study is an investigation of the physicochemical characteristics of three limestone samples, Quincy limestone (-20 + 60), Franklin limestone (-12 + 30), and Franklin limestone (-6 + 16), currently being tested at Oak Ridge National Laboratory for use in a fluidized-bed coal combustion unit. By correlating the chemistry, mineralogy, and surface area of these samples with empirical data obtained at Argonne National Laboratory, the sulfur capture ability and performance of these limestones can be loosely predicted. X-ray fluorescence and neutron activation analysis revealed a very high calcium content and very low concentrations of other elements in the three samples. X-ray diffraction patterns and petrographic examination of the limestone grains detected essentially no dolomite in the Quincy limestone or the fine Franklin limestone samples. The coarse Franklin limestone sample showed dolomite to be present in varying amounts up to maximum of 2.75%. Limited surface chemistry investigations of the samples were undertaken. Limestone and dolostone resources of the Tennessee Valley Authority region are widespread and abundant, and judged sufficient to meet industrial demand for many years. No problems are anticipated in securing limestone or dolostone supplies for a commercial fluidized-bed combustion plant in the Tennessee Valley Authority region. Transportation facilities and costs for limestone or dolostone will influence the siting of such a commercial fluidized-bed combustion plant. The most promising location in the Tennessee Valley Authority region at this time is Paducah, Kentucky.

  7. Staged fluidized-bed combustion and filter system

    DOEpatents

    Mei, Joseph S.; Halow, John S.

    1994-01-01

    A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste.

  8. Performance of a pilot-scale, steam-blown, pressurized fluidized bed biomass gasifier

    NASA Astrophysics Data System (ADS)

    Sweeney, Daniel Joseph

    With the discovery of vast fossil resources, and the subsequent development of the fossil fuel and petrochemical industry, the role of biomass-based products has declined. However, concerns about the finite and decreasing amount of fossil and mineral resources, in addition to health and climate impacts of fossil resource use, have elevated interest in innovative methods for converting renewable biomass resources into products that fit our modern lifestyle. Thermal conversion through gasification is an appealing method for utilizing biomass due to its operability using a wide variety of feedstocks at a wide range of scales, the product has a variety of uses (e.g., transportation fuel production, electricity production, chemicals synthesis), and in many cases, results in significantly lower greenhouse gas emissions. In spite of the advantages of gasification, several technical hurdles have hindered its commercial development. A number of studies have focused on laboratory-scale and atmospheric biomass gasification. However, few studies have reported on pilot-scale, woody biomass gasification under pressurized conditions. The purpose of this research is an assessment of the performance of a pilot-scale, steam-blown, pressurized fluidized bed biomass gasifier. The 200 kWth fluidized bed gasifier is capable of operation using solid feedstocks at feedrates up to 65 lb/hr, bed temperatures up to 1600°F, and pressures up to 8 atm. Gasifier performance was assessed under various temperatures, pressure, and feedstock (untreated woody biomass, dark and medium torrefied biomass) conditions by measuring product gas yield and composition, residue (e.g., tar and char) production, and mass and energy conversion efficiencies. Elevated temperature and pressure, and feedstock pretreatment were shown to have a significant influence on gasifier operability, tar production, carbon conversion, and process efficiency. High-pressure and temperature gasification of dark torrefied biomass

  9. Circulating fluidized bed tehnology in biomass combustion-performance, advances and experiences

    SciTech Connect

    Mutanen, K.I.

    1995-11-01

    Development of fluidized bed combustion (FBC) was started both in North America and in Europe in the 1960`s. In Europe and especially in Scandinavia the major driving force behind the development was the need to find new more efficient technologies for utilization of low-grade fuels like different biomasses and wastes. Both bubbling fluidized bed (BFB) and circulating fluidized bed (CFB) technologies were under intensive R&D,D efforts and have now advanced to dominating role in industrial and district heating power plant markets in Europe. New advanced CFB designs are now entering the markets. In North America and especially in the US the driving force behind the FBC development was initially the need to utilize different types of coals in a more efficient and environmentally acceptable way. The present and future markets seem to be mainly in biomass and multifuel applications where there is benefit from high combustion efficiency, high fuel flexibility and low emissions such as in the pulp and paper industry. The choice between CFB technology and BFB technology is based on selected fuels, emission requirements, plant size and on technical and economic feasibility. Based on Scandinavian experience there is vast potential in the North American industry to retrofit existing oil fired, pulverized coal fired, chemical recovery or grate fired boilers with FBC systems or to build a new FBC based boiler plant. This paper will present the status of CFB technologies and will compare technical and economic feasibility of CFB technology to CFB technology to BFB and also to other combustion methods. Power plant projects that are using advanced CFB technology e.g. Ahlstrom Pyroflow Compact technology for biomass firing and co-firing of biomass with other fuels will also be introduced.

  10. The Operation of Magnetically Assisted Fluidized Bed in Microgravity and Variable Gravity: Experiment and Theory

    NASA Astrophysics Data System (ADS)

    Sornchamni, T.; Jovanovic, G.; Atwater, J.; Akse, J.; Wheeler, R.

    Typically, the operation of a conventional fluidized bed relies on the balance of gravitational, buoyancy, and drag forces. In the absence of normal gravity, or under microgravity and variable gravity conditions, the gravitational force must be replaced with an alternative force to restore fluidization. Our work has shown that, given a suitable variable magnetic field design, the resulting magnetic field gradient can create sufficient magnetic force acting upon the ferromagnetic particles to replace or supplement the gravitational force. Therefore, the ferromagnetic granular media can be fluidized in either microgravity or hypogravity. In this paper, we present our experimental and theoretical work leading to a) development of theoretical model based on fundamental principles for the design of the Gradient Magnetically Assisted Fluidized Bed (G-MAFB), and b) practical implementation of the G-MAFB in the filtration and destruction of solid biowaste particles from liquid streams. The G-MAFB system consists of a fluidization column and series of Helmholtz electromagnetic coils, with DC power supply. Each Helmholtz ring is powered and controlled separately. Experiments are performed in both 0g (on board NASA KC- 135) and 1g (laboratory) environments. The experiments in 0g are conducted in a two-dimensional, square cross-section, tapered fluidization column. The tapered shape is introduced to provide additional stability to the fluidization particles. The experiments in 0g prove that the magnetic force has a significant role in keeping the particles from extruding out of the bed. Without the magnetic force, it is impossible to have fluidization in space. Solid waste destruction technologies are needed to support long duration human habitation in space. The current technologies, including supercritical water oxidation (SCWO), microwave powered combustion and fluidized bed incineration, have been applied to the destruction of solid wastes, but none are compatible with

  11. Results of theoretical and experimental studies of hydrodynamics of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors

    NASA Astrophysics Data System (ADS)

    Ryabov, G. A.; Folomeev, O. M.; Sankin, D. A.; Melnikov, D. A.

    2015-02-01

    Problems of the calculation of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors (polygeneration systems for the production of electricity, heat, and useful products and chemical cycles of combustion and gasification of solid fuels)are considered. A method has been developed for the calculation of circulation loop of fuel particles with respect to boilers with circulating fluidized bed (CFB) and systems with interconnected reactors with fluidized bed (FB) and CFB. New dependences for the connection between the fluidizing agent flow (air, gas, and steam) and performance of reactors and for the whole system (solids flow rate, furnace and cyclone pressure drops, and bed level in the riser) are important elements of this method. Experimental studies of hydrodynamics of circulation loops on the aerodynamic unit have been conducted. Experimental values of pressure drop of the horizontal part of the L-valve, which satisfy the calculated dependence, have been obtained.

  12. A Comparative Study of Euler-Euler and Euler-Lagrange Modelling of Wood Gasification in a Dense Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Gerber, S.; Behrendt, F.; Oevermann, M.

    In this work we compare two different modelling strategies for the simulation of wood gasification in a dense fluidized bed. In the first method we adopt an Euler-Lagrange approach where the fluid phase is modelled as a continuum and the particulate phase is modelled on the individual particle level using the Discrete Element Method (DEM). In the second method we use an Euler-Euler or continuum approach where the multiple solid phases for wood and char particles are treated as a continuum. Both models allow the time-dependent prediction of velocity, temperature, and composition fields. Both models have been run to a statistically stationary state. We compare the numerical results of both methods against each other and with experimental data obtained at a laboratory scale bubbling fluidized bed reactor.

  13. Thermal modeling of microwave heated packed and fluidized bed catalytic reactors.

    PubMed

    Thomas, J R; Faucher, F

    2000-01-01

    Thermal models of small-scale, microwave-heated, packed-bed and fluidized-bed catalytic chemical reactors were developed to investigate the possibility of selectively heating the catalyst sites or the catalyst pellets with microwaves. Results indicate catalyst sites may be selectively heated under special conditions in a packed or fluidized bed, and catalyst pellets may be heated above the temperature of the cooling(and reacting) gas under certain conditions in a fluidized bed. PMID:11098441

  14. Fluidized-bed bioreactor system for the microbial solubilization of coal

    DOEpatents

    Scott, C.D.; Strandberg, G.W.

    1987-09-14

    A fluidized-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fluidized-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fluidized-bed bioreactor. 2 figs.

  15. Fluidized-bed bioreactor process for the microbial solubiliztion of coal

    DOEpatents

    Scott, Charles D.; Strandberg, Gerald W.

    1989-01-01

    A fluidized-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fluidized-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fluidized-bed bioreactor.

  16. Volatiles combustion in fluidized beds. Technical progress report, 4 March 1993--3 June 1993

    SciTech Connect

    Hesketh, R.P.

    1993-09-01

    The goal of this project is to investigate the conditions in which volatiles will burn within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization will be performed to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. The work conducted during the period 4 March, 1993 through 3 June, 1993 is reported in this technical progress report. The work during this time period consists primarily of the startup and trouble shooting of the fluidized bed reactor and gas phase modeling of methane and propane.

  17. Biodiesel production in a magnetically-stabilized, fluidized bed reactor with an immobilized lipase in magnetic chitosan microspheres.

    PubMed

    Zhou, Gui-Xiong; Chen, Guan-Yi; Yan, Bei-Bei

    2014-01-01

    Biodiesel production by immobilized Rhizopus oryzae lipase in magnetic chitosan microspheres (MCMs) was carried out using soybean oil and methanol in a magnetically-stabilized, fluidized bed reactor (MSFBR). The maximum content of methyl ester in the reaction mixture reached 91.3 (w/v) at a fluid flow rate of 25 ml/min and a magnetic field intensity of 150 Oe. In addition, the MCMs-immobilized lipase in the reactor showed excellent reusability, retaining 82 % productivity even after six batches, which was much better than that in a conventional fluidized bed reactor. These results suggested that a MSFRB using MCMs-immobilized lipase is a promising method for biodiesel production. PMID:24062133

  18. Biodiesel production in a magnetically-stabilized, fluidized bed reactor with an immobilized lipase in magnetic chitosan microspheres.

    PubMed

    Zhou, Gui-Xiong; Chen, Guan-Yi; Yan, Bei-Bei

    2014-01-01

    Biodiesel production by immobilized Rhizopus oryzae lipase in magnetic chitosan microspheres (MCMs) was carried out using soybean oil and methanol in a magnetically-stabilized, fluidized bed reactor (MSFBR). The maximum content of methyl ester in the reaction mixture reached 91.3 (w/v) at a fluid flow rate of 25 ml/min and a magnetic field intensity of 150 Oe. In addition, the MCMs-immobilized lipase in the reactor showed excellent reusability, retaining 82 % productivity even after six batches, which was much better than that in a conventional fluidized bed reactor. These results suggested that a MSFRB using MCMs-immobilized lipase is a promising method for biodiesel production.

  19. CFD Analysis of Bubbling Fluidized Bed Using Rice Husk

    NASA Astrophysics Data System (ADS)

    Singh, Ravi Inder; Mohapatra, S. K.; Gangacharyulu, D.

    Rice is Cultivated in all the main regions of world. The worldwide annual rice production could be 666million tons (www.monstersandcritics.com,2008) for year 2008. The annual production of rice husk is 133.2 million tons considering rice husk being 20% of total paddy production. The average annual energy potential is 1.998 *1012 MJ of rice husk considering 15MJ/kg of rice husk. India has vast resource of rice husk; a renewable source of fuel, which if used effectively would reduce the rate of depletion of fossil energy resources. As a result a new thrust on research and development in boilers bases on rice husk is given to commercialize the concept. CFD is the analysis of systems involving fluid flow, heat transfer and associated phenomena such as chemical reactions by means of computer-based simulation. High quality Computational Fluid dynamics (CFD) is an effective engineering tool for Power Engineering Industry. It can determine detailed flow distributions, temperatures, and pollutant concentrations with excellent accuracy, and without excessive effort by the software user. In the other words it is the science of predicting fluid flow, heat and mass transfer, chemical reactions and related phenomena; and an innovate strategy to conform to regulations and yet stay ahead in today's competitive power market. This paper is divided into two parts; in first part review of CFD applied to the various types of boilers based on biomass fuels/alternative fuels is presented. In second part CFD analysis of fluidized bed boilers based on rice husk considering the rice husk based furnace has been discussed. The eulerian multiphase model has used for fluidized bed. Fluidized bed has been modeled using Fluent 6.2 commercial code. The effect of numerical influence of bed superheater tubes has also been discussed.

  20. Sorbent performance in fluidized-bed coal combustion

    SciTech Connect

    Haji Sulaiman, M.Z.

    1988-01-01

    The sulfation behavior of natural limestones and dolomites has been assessed using a bench scale fluidized bed reactor under conditions which are applicable to bubbling atmospheric fluidized bed condition. By increasing the temperature or reducing the CO{sub 2} partial pressure in the calcining gas, both precalcined and uncalcined sorbents exhibited relatively similar behavior on sulfation. Under these conditions calcination was relatively fast and therefore did not influence the overall sulfation process. When preparing precalcined sorbents, their reactivities towards SO{sub 2} depended on the calcining conditions, in particular on the CO{sub 2} concentration in the calcining gas and the calcining temperature. The apparent effects of calcining conditions on the subsequent sulfation behavior were directly related to the physical structure of the solid, which changes as a consequence of sintering. For a particular sorbent there is an optimum pore size beyond which the sulfur uptake begins to decrease. The low sulfur uptake at high temperatures was due to early pore blockage which restricted the transport of SO{sub 2} into the particle. Higher calcium utilization was achieved using impure limestones. When distributed uniformly within the particles, impurities dilute the CaO concentration and help to delay pore blockage upon reaction with SO{sub 2}. In the sulfation of uncalcined sorbents, the presence of impurities will increase the overall rate of calcination. In addition, some impurities will affect the sintering process and ultimately produce a favorable solid structure for sulfation. It can be concluded that the chemical composition of a sorbent should be considered in addition to its physical properties in selecting suitable candidates for reducing SO{sub 2} emissions from fluidized bed combustion.

  1. Wall-to-suspension heat transfer in circulating fluidized beds

    SciTech Connect

    Wirth, K.E.

    1995-12-31

    The wall-to-suspension heat transfer in circulating fluidized beds depends on the fluid mechanics immediately near the wall and on the thermal properties of the gas used. Experimental investigations of circulating fluidized beds of low dimensionless pressure gradients with different solid particles like bronze, glass and polystyrene at ambient temperatures showed no influence of the conductivity and the heat capacity of the solids on the heat transfer coefficient. Consequently the heat transfer coefficient in the form of the dimensionless Nusselt number can be described by the dimensionless numbers which characterize the gas-solid-flow near the wall. These numbers are the Archimedes number and the pressure drop-number. The last number relates the cross-sectional average solids concentration to the solids concentration at minimum fluidization condition. With the aid of a model of segregated vertical gas-solid flow, the flow pattern in the wall region can be calculated and thus the wall heat transfer which depends only on heat conduction in the gas and on the convective heat transfer by the gas. With elevated suspension temperatures, radiation contributes additionally to the heat transfer. When the solids concentration is low, the effect of the radiation on the heat transfer is high. Increasing solids concentration results in a decrease of the radiation effect due to the wall being shielded from the radiation of the hot particles in the core region by the cold solids clusters moving down the wall. A simple correlation is presented for calculating the wall-to-suspension heat transfer in circulating fluidized beds.

  2. Fluidized-bed atomic layer deposition reactor for the synthesis of core-shell nanoparticles

    SciTech Connect

    Didden, Arjen P.; Middelkoop, Joost; Krol, Roel van de; Besling, Wim F. A.; Nanu, Diana E.

    2014-01-15

    The design of a fluidized bed atomic layer deposition (ALD) reactor is described in detail. The reactor consists of three parts that have all been placed in one protective cabinet: precursor dosing, reactor, and residual gas treatment section. In the precursor dosing section, the chemicals needed for the ALD reaction are injected into the carrier gas using different methods for different precursors. The reactor section is designed in such a way that a homogeneous fluidized bed can be obtained with a constant, actively controlled, reactor pressure. Furthermore, no filters are required inside the reactor chamber, minimizing the risk of pressure increase due to fouling. The residual gas treatment section consists of a decomposition furnace to remove residual precursor and a particle filter and is installed to protect the pump. In order to demonstrate the performance of the reactor, SiO{sub 2} particles have been coated with TiO{sub 2} using tetrakis-dimethylamino titanium (TDMAT) and H{sub 2}O as precursors. Experiments with varying pulse times show that saturated growth can be obtained with TDMAT pulse times larger than 600 s. Analysis of the powder with High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) and energy dispersive X-ray spectroscopy confirmed that after 50 cycles, all SiO{sub 2} particles were coated with a 1.6 nm homogenous shell of TiO{sub 2}.

  3. Fluidized-bed atomic layer deposition reactor for the synthesis of core-shell nanoparticles.

    PubMed

    Didden, Arjen P; Middelkoop, Joost; Besling, Wim F A; Nanu, Diana E; van de Krol, Roel

    2014-01-01

    The design of a fluidized bed atomic layer deposition (ALD) reactor is described in detail. The reactor consists of three parts that have all been placed in one protective cabinet: precursor dosing, reactor, and residual gas treatment section. In the precursor dosing section, the chemicals needed for the ALD reaction are injected into the carrier gas using different methods for different precursors. The reactor section is designed in such a way that a homogeneous fluidized bed can be obtained with a constant, actively controlled, reactor pressure. Furthermore, no filters are required inside the reactor chamber, minimizing the risk of pressure increase due to fouling. The residual gas treatment section consists of a decomposition furnace to remove residual precursor and a particle filter and is installed to protect the pump. In order to demonstrate the performance of the reactor, SiO2 particles have been coated with TiO2 using tetrakis-dimethylamino titanium (TDMAT) and H2O as precursors. Experiments with varying pulse times show that saturated growth can be obtained with TDMAT pulse times larger than 600 s. Analysis of the powder with High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) and energy dispersive X-ray spectroscopy confirmed that after 50 cycles, all SiO2 particles were coated with a 1.6 nm homogenous shell of TiO2.

  4. Pressurized circulating fluidized-bed combustion for power generation

    SciTech Connect

    Weimer, R.F.

    1995-08-01

    Second-generation Pressurized Circulating Fluidized Bed Combustion (PCFBC) is the culmination of years of effort in the development of a new generation of power plants which can operate on lower-quality fuels with substantially improved efficiencies, meet environmental requirements, and provide a lower cost of electricity. Air Products was selected in the DOE Clean Coal Technology Round V program to build, own, and operate the first commercial power plant using second-generation PCFBC technology, to be located at an Air Products chemicals manufacturing facility in Calvert City, Kentucky. This paper describes the second-generation PCFBC concept and its critical technology components.

  5. Kinetics of potato drying using fluidized bed dryer.

    PubMed

    Bakal, Sushant Balasaheb; Sharma, Gyanendra Prasad; Sonawane, Somnath P; Verma, Radhachran C

    2012-10-01

    The effect of air temperature and two different shapes (cuboidal and cylindrical) with 3 aspect ratio of each shape on the drying kinetics of potato (Solanum tuberosum) in fluidized bed dryer was investigated. Drying was carried out at 50, 60 and 70°C at 7 m/s air velocity. Drying data were analysed to obtain effective diffusivity of moisture transfer. During drying moisture transfer from potato were described by Fick's diffusion model. Two mathematical models were fitted to experimental data. The Page model gave better fit than simple exponential model. The Arrehnious activation energy value expresses the effect of temperature on diffusivity. PMID:24082273

  6. Variable feed rate mechanism for fluidized bed asbestos generators

    SciTech Connect

    Sussman, R.G.; Gearhart, J.M.; Lippmann, M.

    1985-01-01

    A simple and inexpensive dust feed mechanism has been designed for use with a two-phase fluidized bed generator (FBG). The mechanism is especially useful for generating asbestos aerosols, but may be used with other dusts as well. Using this system, a steady state concentration (39.1 fibers/cc > 5 ..mu..m in length +/- 6.2%) of asbestos aerosol was maintained in an inhalation chamber for five hours. In addition, FBG output concentration was easily adjusted and quickly equilibrated (within 10 minutes). The system provides a good technique for generating asbestos aerosols for day-long animal exposures.

  7. Pressure Fluctuations as a Disgnostic Tool for Fluidized Beds.

    SciTech Connect

    Brown, R.C.; Schroeder, J.R.

    1997-10-28

    The validity of using bubbling fluidized bed (BFB) similitude parameters to match a hot BFB to a cold BFB is being studied. Sand in a BFB combustor and copper powder in cold BFB model have been analyzed and found to be out of similitude. In the analysis process, it was determined that the condition of the screen covering the pressure tap affects the quality of pressure data recorded. In addition, distributor plate design and condition will affect the hydrodynamics of the bed. Additional tests are planned to evaluate the validity of similitude concepts in BFB.

  8. Thermal energy storage systems using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Ramanathan, V.; Weast, T. E.; Ananth, K. P.

    1980-01-01

    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.

  9. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project. Annual report, 1988

    SciTech Connect

    Not Available

    1991-01-01

    This Annual Report on Colorado-Ute Electric Association`s NUCLA Circulating Fluidized Bed (CFB) Demonstration Program covers the period from February 1987 through December 1988. The outline for presentation in this report includes a summary of unit operations along with individual sections covering progress in study plan areas that commenced during this reporting period. These include cold-mode shakedown and calibration, plant commercial performance statistics, unit start-up (cold), coal and limestone preparation and handling, ash handling system performance and operating experience, tubular air heater, baghouse operation and performance, materials monitoring, and reliability monitoring. During this reporting period, the coal-mode shakedown and calibration plan was completed. (VC)

  10. Maltodextrin hydrolysis in a fluidized-bed immobilized enzyme reactor

    SciTech Connect

    Vallat, I.; Monsan, P.; Riba, J.P.

    1986-02-01

    The present work deals with maltodextrin hydrolysis by glucoamylase immobilized onto corn stover in a fluidized bed reactor. An industrial enzyme preparation was convalently grafted onto corn stover, yielding an activity of up to 372 U/g and 1700 U/g for support particle sizes of 0.8 and 0.2 mm, respectively. A detailed kinetic study, using a differntial reactor, allowed the characterization of the influence of mass transfer resistance on the reaction catalyzed by immobilized glucoamylase. A simple and general mathematical model was then developed to describe the experimental conversion data and found to be vaild.

  11. Standby cooling system for a fluidized bed boiler

    DOEpatents

    Crispin, Larry G.; Weitzel, Paul S.

    1990-01-01

    A system for protecting components including the heat exchangers of a fluidized bed boiler against thermal mismatch. The system includes an injection tank containing an emergency supply of heated and pressurized feedwater. A heater is associated with the injection tank to maintain the temperature of the feedwater in the tank at or about the same temperature as that of the feedwater in the heat exchangers. A pressurized gas is supplied to the injection tank to cause feedwater to flow from the injection tank to the heat exchangers during thermal mismatch.

  12. Solid fuel feed system for a fluidized bed

    DOEpatents

    Jones, Brian C.

    1982-01-01

    A fluidized bed for the combustion of coal, with limestone, is replenished with crushed coal from a system discharging the coal laterally from a station below the surface level of the bed. A compartment, or feed box, is mounted at one side of the bed and its interior separated from the bed by a weir plate beneath which the coal flows laterally into the bed while bed material is received into the compartment above the plate to maintain a predetermined minimum level of material in the compartment.

  13. Removal of hazardous gaseous pollutants from industrial flue gases by a novel multi-stage fluidized bed desulfurizer.

    PubMed

    Mohanty, C R; Adapala, Sivaji; Meikap, B C

    2009-06-15

    Sulfur dioxide and other sulfur compounds are generated as primary pollutants from the major industries such as sulfuric acid plants, cupper smelters, catalytic cracking units, etc. and cause acid rain. To remove the SO(2) from waste flue gas a three-stage counter-current multi-stage fluidized bed adsorber was developed as desulfurization equipment and operated in continuous bubbling fluidization regime for the two-phase system. This paper represents the desulfurization of gas mixtures by chemical sorption of sulfur dioxide on porous granular calcium oxide particles in the reactor at ambient temperature. The advantages of the multi-stage fluidized bed reactor are of high mass transfer and high gas-solid residence time that can enhance the removal of acid gas at low temperature by dry method. Experiments were carried out in the bubbling fluidization regime supported by visual observation. The effects of the operating parameters such as sorbent (lime) flow rate, superficial gas velocity, and the weir height on SO(2) removal efficiency in the multistage fluidized bed are reported. The results have indicated that the removal efficiency of the sulfur dioxide was found to be 65% at high solid flow rate (2.0 kg/h) corresponding to lower gas velocity (0.265 m/s), wier height of 70 mm and SO(2) concentration of 500 ppm at room temperature.

  14. Pulsed atmospheric fluidized bed combustion. Technical progress report, April 1992--June 1992

    SciTech Connect

    Not Available

    1992-08-01

    The general specifications for a Pulsed Atmospheric Fluidized Bed Combustor Design Report (PAFBC) plant are presented. The design tasks for the PAFBC are described in the following areas: Coal/Limestone preparation and feed system; pulse combustor; fluidized bed; boiler parts; and ash handling system.

  15. Fluidized bed boiler at the Royal Alexandra Hospital for Children, Camperdown.

    PubMed

    Ellis, J W

    1985-03-01

    A fluidized bed boiler has been installed at the Royal Alexandra Hospital for Children, Camperdown, N.S.W. This paper describes the reasons for developing a project to demonstrate that a fluidized bed coal fire combustor can be incorporated with a modern packaged steam boiler. The boiler and combustor are of Australian design as suitable proven designs from overseas were not available.

  16. Biofilm detachment mechanisms in a liquid-fluidized bed.

    PubMed

    Chang, H T; Rittmann, B E; Amar, D; Heim, R; Ehlinger, O; Lesty, Y

    1991-08-20

    Bed fluidization offers the possibility of gaining the advantages of fixed-film biological processes without the disadvantage of pore clogging. However, the biofilm detachment rate, due to hydrodynamics and particle-to-particle attrition, is very poorly understood for fluidized-bed biofilm processes. In this work, a two-phase fluidized-bed biofilm was operated under a constant surface loading (0.09 mg total organic carbon/cm(2) day) and with a range of bed height (H), fluid velocities (U), and support-particle concentrations (C(p)). Direct measurements were made for the specific biofilm loss rate coefficient (b(s))and the total biofilm accumulation (X(f)L(f)). A hydrodynamic model allowed independent determination of the biofilm density (X(f)), biofilm thickness (L(f)), liquid shear stress (tau), and Reynolds number (Re). Multiple regression analysis of the results showed that increased particle-to-particle attrition, proportional to C(p) and increased turbulence, described by Re, caused the biofilms to be denser and thinner. The specific detachment rate coefficient (b(s)) increased as C(p) and Re increased. Almost all of the 6, values were larger than predicted by a previous model derived for smooth biofilms on a nonfluidized surface. Therefore, the turbulence and attrition of bed fluidization appear to be dominant detachment mechanisms.

  17. Reduction of particulate carryover from a pressurized fluidized bed

    NASA Technical Reports Server (NTRS)

    Patch, R. W.

    1979-01-01

    A bench scale fluidized bed combustor was constructed with a conical shape so that the enlarged upper part of the combustor would also serve as a granular bed filter. The combustor was fed coal and limestone. Ninety-nine tests of about four hours each were conducted over a range of conditions. Coal-to-air ratio varied from 0.033 to 0.098 (all lean). Limestone-to-coal ratio varied from 0.06 to 0.36. Bed depth varied from 3.66 to 8.07 feet. Temperature varied from 1447 to 1905 F. Pressure varied from 40 to 82 psia. Heat transfer area had the range zero to 2.72 ft squared. Two cone angles were used. The average particulate carry over of 2.5 grains/SCF was appreciably less than cylindrical fluidized bed combustors. The carry over was correlated by multiple regression analysis to yield the dependence on bed depth and hence the collection efficiency, which was 20%. A comparison with a model indicated that the exhaust port may be below the transport disengaging height for most of the tests, indicating that further reduction in carry over and increase in collection efficiency could be affected by increasing the freeboard and height of the exhaust port above the bed.

  18. Evaluation of Fluidized Beds for Mass Production of IFE Targets

    SciTech Connect

    Huang, H.; Vermillion, B.A.; Brown, L.C.; Besenbruch, G.E.; Goodin, D.T.; Stemke, R.W.; Stephens, R.B.

    2005-01-15

    Of the building blocks of an inertial fusion energy (IFE) plant, target fabrication remains a significant credibility issue. For this reason, an extensive parametric study has been conducted on mass production of glow discharge polymer (GDP) shells in a vertical fluidized bed. Trans-2-butene was used as a reactant gas with hydrogen as a diluting and etching agent. Coating rates in the range of 1 to 2 {mu}m/h were demonstrated on batches of 30 shells where National Ignition Facility-quality surfaces were obtained for 3- to 5-{mu}m-thick coatings. Thick coatings up to 325 {mu}m were also demonstrated that are visually transparent, without void and stress fracture. A phenomenological understanding of the GDP growth mechanisms to guide future experiments was further established. Specifically, gas-phase precipitation and high-impact collisions were identified as the main surface-roughening mechanisms. The former produces dense cauliflower-like surface patterns that can be eliminated by adjusting the gas flow rates and the flow ratio. The latter produces isolated domelike surface defects that can be reduced by introducing concerted motion between the shells. By converting from a vertical to a horizontal configuration, fully transparent coatings were obtained on 350 shells. Collisions in a fluidized bed have been identified as the limiting factor in meeting IFE specifications, and a related-rotary kiln technique is recommended for scale-up.

  19. Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

    SciTech Connect

    Sibashis Banerjee; Alvin Chen; Rutton Patel; Dale Snider; Ken Williams; Timothy O'Hern; Paul Tortora

    2008-02-29

    The work detailed in this report addresses Enabling Technologies within Computational Technology by integrating a “breakthrough” particle-fluid computational technology into traditional Process Science and Engineering Technology. The work completed under this DOE project addresses five major development areas 1) gas chemistry in dense fluidized beds 2) thermal cracking of liquid film on solids producing gas products 3) liquid injection in a fluidized bed with particle-to-particle liquid film transport 4) solid-gas chemistry and 5) first level validation of models. Because of the nature of the research using tightly coupled solids and fluid phases with a Lagrangian description of the solids and continuum description of fluid, the work provides ground-breaking advances in reactor prediction capability. This capability has been tested against experimental data where available. The commercial product arising out of this work is called Barracuda and is suitable for a wide (dense-to-dilute) range of industrial scale gas-solid flows with and without reactions. Commercial applications include dense gas-solid beds, gasifiers, riser reactors and cyclones.

  20. Effect of slugging phenomena on drag coefficient in fluidized beds

    SciTech Connect

    Bakhtiyarov, S.I.; Overfelt, R.A.

    1996-12-31

    Slugging is an abnormality in which gas bubbles increase to the diameter of the fluidization chamber. The slugs of solid particles will move upward in a pistonlike manner, reach a certain height, and then rain through the gas phase in the form of aggregates or as individual particles. The effect of slugging phenomenon on drag coefficient in fluidized beds is assessed by developing theoretical and experimental analyses of this problem. The theoretical analysis of the slugging in fluidized beds was based on a momentum balance equation for the axial flow of gas around a slug and Meshchersky`s differential equation of motion of a slug having variable mass. To predict the flow rate of the gas flow through the slug the authors used the Blake-Kozeny-Carman equation. From the analytical solution of the problem, the expressions for the pressure drop and the drag coefficient as functions of the Reynolds number, slug porosity, gas viscosity and chamber sizes have been developed. Experiments were run in a fluidization chamber with foundry sand of 2.593 g/cc average density and 30--270 mesh size at three different values of the fixed bed height. The results of simulations demonstrate that both the drag coefficient and the resistance factor decrease with increasing the Reynolds number and increasing the porosity of slug. A comparison of the results obtained in the experiments demonstrates a qualitative agreement with the theoretical model simulations.

  1. Fluidized-bed combustion and gasification of biomass

    SciTech Connect

    LePori, W.A.; Anthony, R.G.; Lalk, T.R.; Craig, J.D.

    1981-01-01

    A 0.61 meter (2 ft) diameter fluidized-bed combustion reactor was used for tests on direct combustion of cotton gin trash. Raw gin trash was continuously augered into the unit with fuel and air rates set to maintain bed temperatures of 760/sup 0/ to 816/sup 0/C (1400/sup 0/ to 1500/sup 0/F). Particulate emissions in the hot stack gases were measured and found to be lower than federal standards for incinerators. Mild steel and stainless alloy samples were placed in the hot stack gas stream to study corrosion and erosion of materials. High rates of potassium, calcium, and sodium deposits accumulated on the samples, and high erosion rates were found. A 0.3 meter (13 in) diameter fluidized-bed gasifier was used to convert raw gin trash into a combustible gas with bed temperatures between 683/sup 0/C and 881/sup 0/C (1261/sup 0/F and 1618/sup 0/F). By limiting the amount of oxygen compared to the fuel feed, only partial combustion occurs, producing heat and endothermic gasification chemical reactions. The combustible gas was composed primarily of carbon monoxide and hydrogen. It had a heating value ranging from 3.40 to 4.82 M Joules per standard cubic meter (98 to 142 Btu/scf), and about 50 percent of the heat value of the gin trash was converted into this low energy gas.

  2. Integrated drying and incineration of wet sewage sludge in combined bubbling and circulating fluidized bed units.

    PubMed

    Li, Shiyuan; Li, Yunyu; Lu, Qinggang; Zhu, Jianguo; Yao, Yao; Bao, Shaolin

    2014-12-01

    An original integrated drying and incineration technique is proposed to dispose of sewage sludge with moisture content of about 80% in a circulating fluidized bed. This system combines a bubbling fluidized bed dryer with a circulating fluidized bed incinerator. After drying, sewage sludge with moisture less than 20% is transported directly and continuously from the fluidized bed dryer into a circulating fluidized bed incinerator. Pilot plant results showed that integrated drying and incineration is feasible in a unique single system. A 100 t/d Sewage Sludge Incineration Demonstration Project was constructed at the Qige sewage treatment plant in Hangzhou City in China. The operational performance showed that the main operation results conformed to the design values, from which it can be concluded that the scale-up of this technique is deemed both feasible and successful.

  3. Coal and biomass co-combustion on fluidized bed: Comparison of circulating and bubbling fluidized bed technologies

    SciTech Connect

    Armesto, L.; Cabanillas, A.; Bahillo, A.; Segovia, J.J.; Escalada, R.; Martinez, J.M.; Carrasco, J.E.

    1997-12-31

    The main objective of the proposed paper is to demonstrate the technical feasibility of fluidized bed as a clean technology for the combustion of low grade coal/biomass blends. The raw materials used as fuels in the tests are different blends of the following materials: refuse coal with a heating value of 3,658 kJ/kg (LHV, db) and 79.65% ash content; low grade coal--lignite with a heating value of 19952 kJ/kg (LHV, db), a sulfur content of 10.32% (db) and 23.70% ash content; and biomass--forestry wastes from wood cleaning whose heating value is 19555 kJ/kg (LHV, db). An absorbent, limestone, has been used for reducing sulfur emissions. Co-combustion tests, at the pilot plant level, have been carried out by using two fluidized bed technologies, circulating and bubbling. The object of this paper is to study, in an energy and emission point of view, the clean and efficient use of these resources. The paper collects, analyses and compares combustion test data.

  4. Fluidized bed electrowinning of chromium from very dilute solutions

    SciTech Connect

    Hu, X.; Bautista, R.G.

    1988-10-01

    The Fluidized Bed Electrochemical Reactor (FBER) was used to electrowin chromium from very dilute solutions, ranging in concentration from 0.52 to 3.12 g Cr/1 at pH = 2. The cathode consisted of particulate chromium (450-600 ..mu..m diam.) with a current feeder made of carbon bars and a tubular lead anode in a cylindrical cell. The current efficiency was in the range of 0.08-0.22. The bed expansion, deposition rate, conversion ratio of Cr(VI) to Cr(III) and voltage - current characteristic of the cell were studied. The results indicate that the use of the FBER will make possible the removal of chromium from very dilute solutions without the introduction of other chemicals which would need to be removed or treated further downstream to satisfy environmental abatement codes.

  5. Nucla circulating atmospheric fluidized bed demonstration project. Final report

    SciTech Connect

    Not Available

    1991-10-01

    Colorado-Ute Electric Association began a study to evaluate options for upgrading and extending the life of its Nucla power station in 1982. Located in southwestern Colorado near the town of Nucla, this station was commissioned in 1959 with a local bituminous coal as its design fuel for three identical stoker-fired units, each rated at 12.6 MW(e). Poor station efficiency, high fuel costs, and spiraling boiler maintenance costs forced the Nucla Station into low priority in the CUEA dispatch order as early as 1981. Among the options CUEA considered was to serve as a host utility to demonstrate Atmospheric Fluidized Bed Combustion (AFBC) technology. The anticipated environmental benefits and apparent attractive economics of a circulating AFBC led to Colorado-Ute`s decision to proceed with the design and construction of a demonstration project in 1984 at the Nucla facility.

  6. Biological fluidized bed reactor (FBR): Emissionless groundwater treatment

    SciTech Connect

    Hines, R.D. Jr.; Laubacher, R.C.; Kunce, L.K.

    1996-12-31

    Groundwater treatment costs in the 1990`s have gone up significantly due to the air regulations that allow minimal or no VOC emissions. Treatment for air stripper off-gas has typically been vapor-phase carbon or catalytic oxidation. A more cost-effective alternative for groundwater treatment using a biological Granular Activated Carbon (GAC) Fluidized Bed Reactor (FBR) has been implemented successfully in remediating groundwater at two BP Distribution terminals. In the FBR system, GAC is the support media for biological growth, as well as a mechanism for organic adsorption. The FBR system predissolves self-generated pure oxygen to promote the aerobic degradation of dissolved hydrocarbons as they pass through the biofilm attached to the GAC. The use of predissolved pure oxygen prevents the air stripping action of conventional biological systems. Any hydrocarbons not rapidly broken down are adsorbed and subsequently degraded. The result is a high quality effluent without release of VOC air emissions. 4 refs., 3 figs.

  7. Technical evaluation: pressurized fluidized-bed combustion technology

    SciTech Connect

    Miller, S A; Vogel, G J; Gehl, S M; Hanway, Jr, J E; Henry, R F; Parker, K M; Smyk, E B; Swift, W M; Podolski, W F

    1982-04-01

    The technology of pressurized fluidized-bed combustion, particularly in its application to a coal-burning combined-cycle plant, is evaluated by examining the technical status of advanced-concept plant components - boiler system (combustor, air-handling and air-injection equipment, and heat exchangers); solids handling, injection, and ejection system; hot-gas cleanup equipment; instrumentation/control system; and the gas turbine - along with materials of plant construction. Environmental performance as well as energy efficiency are examined, and economic considerations are reviewed briefly. The evaluation concludes with a broad survey of the principal related research and development programs in the United States and other countries, a foreview of the most likely technological developments, and a summary of unresolved technical issues and problems.

  8. Sulfur capture in an atmospheric fluidized-bed combustor

    SciTech Connect

    Baars, D.M.; Hunter, C.A.; Keitelman, E.N.

    1981-06-01

    Sulfur capture in an atmospheric fluidized-bed combustor (AFBC) both with and without recycle of fines elutriated from the bed was studied. Two empirical correlations, one by Babcock and Wilcox and the other by Westinghouse, correlate sulfur capture as a function of the calcium-to-sulfur mole ratio and gas residence time. Both correlations fit the experimental no-recycle results quite well. Of the limestones tested with no recycle, Vulcan Materials exhibits the best sulfur-capture performance. Data collected with Reed limestone indicates that recycle improves sulfur-capture compared with once-through performance. However, there is a decreasing effect on sulfur capture as the recycle rate is increased to large values. At 90% sulfur capture, the fractional reduction of fresh limestone feed attributable to recycle is 24 to 35% over a gas-residence time range of 0.7 to 0.4 s.

  9. Cyclone performance estimates for pressurized fluidized-bed combustion

    SciTech Connect

    Henry, R.F.; Podolski, W.F.

    1981-07-01

    Hot pressurized flue gas from pressurized fluidized-bed combustion must be cleaned up prior to its expansion in a gas turbine as part of the combined-cycle electric power generation concept. The performance of conventional cyclones in experimental tests has been compared with theory, with reasonable agreement. Prediction of the performance of a larger cyclone system shows that three stages should provide the cleanup required on the basis of current estimates of turbine tolerance of particulate matter. Advances in hot gas cleanup - optimized cyclones, augmented cyclones, and alternative devices - should provide future improvement in cycle efficiencies and costs, but simple cyclones are planned for first-generation PFB/CC pilot and demonstration plants.

  10. Continuous fluidized-bed contactor with recycle of sorbent

    DOEpatents

    Scott, Charles D.; Petersen, James N.; Davison, Brian H.

    1996-01-01

    A continuous fluidized-bed contactor containing sorbent particles is used to remove solutes from liquid solvents. As the sorbent particles, for example gel beads, sorb the solute, for example metal ion species, the sorbent particles tend to decrease in diameter. These smaller loaded sorbent particles rise to the top of the contactor, as larger sorbent particles remain at the bottom of the contactor as a result of normal hydraulic forces. The smaller loaded sorbent particles are then recovered, regenerated, and reintroduced into the contactor. Alternatively, the loaded sorbent particles may also slightly increase in diameter, or exhibit no change in diameter but an increase in density. As a result of normal hydraulic forces the larger loaded sorbent particles fall to the bottom of the contactor. The larger loaded sorbent particles are then recovered, regenerated, and reintroduced into the contactor.

  11. Oxy-combustion of biomass in a circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Kosowska-Golachowska, Monika; Kijo-Kleczkowska, Agnieszka; Luckos, Adam; Wolski, Krzysztof; Musiał, Tomasz

    2016-03-01

    The objective of this study was to investigate combustion characteristics of biomass (willow, Salix viminalis) burnt in air and O2/CO2 mixtures in a circulating fluidized bed (CFB). Air and oxy-combustion characteristics of wooden biomass in CFB were supplemented by the thermogravimetric and differential thermal analyses (TGA/DTA). The results of conducted CFB and TGA tests show that the composition of the oxidizing atmosphere strongly influences the combustion process of biomass fuels. Replacing N2 in the combustion environment by CO2 caused slight delay (higher ignition temperature and lower maximum mass loss rate) in the combustion of wooden biomass. The combustion process in O2/CO2 mixtures at 30% and 40% O2 is faster and shorter than that at lower O2 concentrations.

  12. Continuous fluidized-bed contactor with recycle of sorbent

    DOEpatents

    Scott, C.D.; Petersen, J.N.; Davison, B.H.

    1996-07-09

    A continuous fluidized-bed contactor containing sorbent particles is used to remove solutes from liquid solvents. As the sorbent particles, for example gel beads, sorb the solute, for example metal ion species, the sorbent particles tend to decrease in diameter. These smaller loaded sorbent particles rise to the top of the contactor, and larger sorbent particles remain at the bottom of the contactor as a result of normal hydraulic forces. The smaller loaded sorbent particles are then recovered, regenerated, and reintroduced into the contactor. Alternatively, the loaded sorbent particles may also slightly increase in diameter, or exhibit no change in diameter but an increase in density. As a result of normal hydraulic forces the larger loaded sorbent particles fall to the bottom of the contactor. The larger loaded sorbent particles are then recovered, regenerated, and reintroduced into the contactor. 8 figs.

  13. A fluidized-bed continuous bioreactor for lactic acid production

    SciTech Connect

    Andrews, G.F.; Fonta, J.P.

    1988-05-01

    A laboratory bioreactor consists of a fluidized bed of monosized activated carbon coated with a biofilm of the homolactic fermentative organism Streptococcus thermophilus. Biofilm growth moves the carbon through the bed, and adsorption of substrate and product at the bottom and top of the bed respectively reduces their inhibitory effects on the organism. Theory shows that high reactor productivity and rapid recirculation of carbon through the bed require a biofilm thickness of 25 to 45% of the carbon particle radius on particles fed into the base of the bed. This could not be achieved in practice due to the fragility of the biofilm. Product concentration was higher than expected from measurements of product inhibition, possibly because it is the undissociated form of the acid that both inhibits metabolism and adsorbs on the activated carbon. The observed productivity of 12 gm/1 hr could be greatly increased by ph control. 13 refs., 7 figs., 2 tabs.

  14. Oil shale loss from a laboratory fluidized bed

    SciTech Connect

    Taylor, R.W.; Beavers, P.L. )

    1989-01-01

    The rate of loss of dust from a laboratory-scale fluidized bed of Greenriver oil shale has been measured. The rate of loss of dust form raw shale in the bed was approximately 1%/min for the first few minutes and then decreased. The loss rate for retorted or burnt shale was 5 to 10 times higher. The rates for retorted and burned shale were nearly the same. The time required for a 10 wt% loss of mass was approximately 3 min for processed shale and 1 hour for raw shale. Particles left in the bed during fluidization lost sharp corners, but kept the original elongation. Dust lost by the bed has a very wide range of sizes and demonstrated a strong bimodal distribution of sizes. The bimodal distribution of particles is interpreted as resulting from two mechanisms of dust generation; fracture and wear.

  15. A fluidized bed process for electron sterilization of powders

    NASA Astrophysics Data System (ADS)

    Nablo, Sam V.; Wood, James C.; Desrosiers, Marc F.; Nagy, Vitaly Yu.

    1998-06-01

    A small capacity (100 g.s -1) pilot system is described for presentation of powders and fine aggregates at high velocity, to an electron beam. Electron beam dose rate is continuously monitored in real time, while the thickness of the fluidized bed used to pneumatically transport the product can be monitored and controlled using beta-gauge techniques. Using electron paramagnetic resonance (EPR) techniques, alanine power mixed with the product is used for precise determination of dose delivered to the powder stream. Thin film dosimeters transported in the bed are also used for dose determination. Results with a variety of products are presented using both dose rate and velocity as the independent variables. Lethality data for the bioburdens present in several powdered foodstuffs are discussed.

  16. Pressurized fluidized-bed hydroretorting of eastern oil shales

    SciTech Connect

    Lau, F.S.; Mensinger, M.C.; Roberts, M.J.; Rue, D.M.

    1991-12-01

    The overall objective of this project is to perform the research necessary to develop the pressurized fluidized-bed hydroretorting (PFH) process for producing oil from Eastern oil shales. The program also incorporates research on technologies in areas such as raw shale preparation, beneficiation, product separation, and waste disposal that the potential of improving the economics and/or environmental acceptability of recovering oil from oil shales using the PFH process. The program is divided into the following tasks: Testing of Process Improvement Concepts; Beneficiation Research; Operation of PFH on Beneficiated Shale; Environmental Data and Mitigation Analyses; Sample Procurement, Preparation, and Characterization; and Project Management and Reporting. Accomplishments for this period for these tasks are presented.

  17. Heat transfer characteristics of the fluidized bed through the annulus

    NASA Astrophysics Data System (ADS)

    Shedid, Mohamed H.; Hassan, M. A. M.

    2016-09-01

    The annular fluidized bed can be regarded as a promising technique for waste heat recovery applications. This study investigates on the determination of steady state values of the average heat transfer on the surface of the inner tube under different operating conditions that include: (1) input heat flux ranging from 557 to 1671 W/m2, (2) superficial air velocity ranging between 0.12 and 0.36 m/s, (3) initial bed height ranging from 25 to 55 cm, (4) ratio of the inner to the outer diameters ranging from 1/6 to 1/2 and Kaolin particle diameters ranging between 282 and 550 µm. The average values of the heat transfer coefficient along the inner tube (consisting of the fluidized and free board sections) are also deduced. An empirical correlation for calculating the Nusselt number is obtained for the given parameters and ranges.

  18. Development of second-generation pressurized fluidized bed combustion process

    SciTech Connect

    Wolowodiuk, W.; Robertson, A.; Bonk, D.

    1995-12-01

    Under the sponsorship of the United States Department of Energy, Foster Wheeler Development Corporation, and its team members, Westinghouse, Gilbert/Commonwealth, and the Institute of Gas Technology are developing second-generation pressurized fluidized bed combustion technology capable of achieving net plant efficiency in excess of 45 percent based on the higher heating value of the coal. A three-phase program entails design and costing of a 500 MWe power plant and identification of developments needed to commercialize this technology (Phase 1), testing of individual components (Phase 2), and finally testing these components in an integrated mode (Phase 3). This paper briefly describes the results of the first two phases as well as the progress on the third phase. Since other projects which use the same technology are in construction or in negotiation stages-namely, the Power System Development Facility and the Four Rivers Energy Modernization Projects-brief descriptions of these are also included.

  19. University picks Riley Stoker to supply fluidized bed boiler

    SciTech Connect

    Block, P.

    1986-02-17

    By installing a circulating fluidized bed boiler rather than a conventional coal-fired boiler, the University of Missouri expects to save $500,000 a year in pollution control costs and $80,000 a year in coal costs. The new $6 million, 200,000 pound per hour boiler, manufactured by Riley Stoker Corp., Worcester, Mass., cost about $1 million more than a conventional stoker-fired boiler, and should pay for itself in combined coal and lime savings in less than two years, according to Bob Bibb, president of Bibb and Associates, Shawnee Mission, Kan., the engineering firm that aided university officials in evaluating bids for the project. As part of the project, two steam turbines will be connected: one 19.5 MW unit to the new boiler and a 14.5 MW unit to an existing boiler. The turbine on the existing boiler will be used for backup power when the first turbine is inoperative.

  20. Design and Application of Novel Horizontal Circulating Fluidized Bed Boiler

    NASA Astrophysics Data System (ADS)

    Lit, Q. H.; Zhang, Y. G.; Meng, A. H.

    The vertical circulating fluidized bed (CFB) boiler has been found wide application in power generation and tends to be enlarged in capacity. Because CFB is one of environment friendly and high efficiency combustion technologies, the CFB boiler has also been expected to be used in the industrial area, such as textile mill, region heating, brewery, seed drying and so on. However, the necessary height of furnace is hard to be implemented for CFB with especially small capacity. Thereby, a novel horizontal circulating fluidized bed boiler has been proposed and developed. The horizontal CFB is composed of primary combustion chamber, secondary combustion chamber, burnout chamber, cyclone, loop seal, heat recovery area. The primary combustion chamber is a riser like as that in vertical CFB, and the secondary combustion chamber is a downward passage that is a natural extension of the primary riser, which can reduce the overall height of the boiler. In some extent, the burnout chamber is also the extension of primary riser. The capacity of horizontal CFB is about 4.2-24.5MWth (6-35t/h) steam output or equivalent hot water supply. The hot water boiler of 7MWth and steam boilers of 4.2MWth (6t/h) and 10.5MWth (15t/h) are all designed and working well now. The three units of hot water horizontal CFB boiler were erected in the Neimenggu Autonomous Region, Huhehaote city for region heating. The three units of steam horizontal CFB has been installed in Yunnan, Jiang Xi and Guangdong provinces, respectively. The basic principle for horizontal CFB and experiences for designing and operating are presented in this paper. Some discussions are also given to demonstrate the promising future of horizontal CFB.

  1. Thermofluid effect on energy storage in fluidized bed reactor

    NASA Astrophysics Data System (ADS)

    Mahfoudi, Nadjiba; El Ganaoui, Mohammed; Moummi, Abdelhafid

    2016-05-01

    The development of innovative systems of heat storage is imperative to improve the efficiency of the existing systems used in the thermal solar energy applications. Several techniques were developed and realized in this context. The technology of the sand fluidized bed (sandTES) offers a promising alternative to the current state-of-the-art of the heat storage systems, such as fixed bed using a storage materials, as sand, ceramic, and stones, etc. Indeed, the use of the fluidization technique allows an effective heat transfer to the solid particles. With the sand, an important capacity of storage is obtained by an economic and ecological material [N. Mahfoudi, A. Moummi, M. El Ganaoui, Appl. Mech. Mater. 621, 214 (2014); N. Mahfoudi, A. Khachkouch, A. Moummi B. Benhaoua, M. El Ganaoui, Mech. Ind. 16, 411 (2015); N. Mahfoudi, A. Moummi, M. El Ganaoui, F. Mnasri, K.M. Aboudou, 3e Colloque internationale Francophone d"énergétique et mécanique, Comores, 2014, p. 91]. This paper presents a CFD simulation of the hydrodynamics and the thermal transient behavior of a fluidized bed reactor of sand, to determine the characteristics of storage. The simulation shows a symmetry breaking that occurs and gave way to chaotic transient generation of bubble formation after 3 s. Furthermore, the predicted average temperature of the solid phase (sand) increases gradually versus the time with a gain of 1 °C in an interval of 10 s. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  2. Bed material agglomeration during fluidized bed combustion. Final report

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Smeenk, J.L.

    1996-01-01

    The purpose of this project is to determine the physical and chemical reactions which lead to the undesired agglomeration of bed material during fluidized bed combustion of coal and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed combustors (FBCs) indicate that at least five boilers were experiencing some form of bed material agglomeration. Deposit formation was reported at nine sites with deposits most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Three general types of mineralogic reactions were observed to occur in the agglomerates and deposits. Although alkalies may play a role with some {open_quotes}high alkali{close_quotes} lignites, we found agglomeration was initiated due to fluxing reactions between iron (II) from pyrites and aluminosilicates from clays. This is indicated by the high amounts of iron, silica, and alumina in the agglomerates and the mineralogy of the agglomerates. Agglomeration likely originated in the dense phase of the FBC bed within the volatile plume which forms when coal is introduced to the boiler. Secondary mineral reactions appear to occur after the agglomerates have formed and tend to strengthen the agglomerates. When calcium is present in high amounts, most of the minerals in the resulting deposits are in the melilite group (gehlenite, melilite, and akermanite) and pyroxene group (diopside and augite). During these solid-phase reactions, the temperature of formation of the melilite minerals can be lowered by a reduction of the partial pressure of CO{sub 2} (Diopside + Calcite {r_arrow}Akermanite).

  3. Simulation on gasification of forestry residues in fluidized beds by Eulerian-Lagrangian approach.

    PubMed

    Xie, Jun; Zhong, Wenqi; Jin, Baosheng; Shao, Yingjuan; Liu, Hao

    2012-10-01

    A comprehensive three-dimensional numerical model is developed to simulate forestry residues gasification in a fluidized bed reactor using Eulerian-Lagrangian approach. The complex granular flow behaviors and chemical reaction characteristics are addressed simultaneously. The model uses an Eulerian method for fluid phase and a discrete particle method for solid phase, which takes particle contact force into account. Heterogeneous and homogenous reaction rates are solved on the Eulerian grid. The numerical model is employed to study the gasification performance in a lab-scale pine gasifier. A series of simulations have been performed with some critical parameters including temperature, equivalence ratio and steam to biomass ratio. The model predicts product gas composition and carbon conversion efficiency in good agreement with experimental data. The formation and development of flow regimes, profiles of particle species, and distributions of gas compositions inside the reactor are also discussed.

  4. Riser simulation and radial porosity distribution characterization for gas-fluidized bed of cork particles

    NASA Astrophysics Data System (ADS)

    Wu, Guorong; Ouyang, Jie; Li, Qiang

    2014-08-01

    Numerical simulations are carried out for gas-solid fluidized bed of cork particles, using discrete element method. Results exhibit the existence of a so-called anti core-annular porosity profile with lower porosity in the core and higher porosity near the wall for non-slugging fluidization. The tendency to form this unfamiliar anti core-annular porosity profile is stronger when the solid flux is higher. There exist multiple inflection points in the simulated axial solid volume fraction profile for non-slugging fluidization. Results also show that the familiar core-annular porosity profile still appears for slugging fluidization. In addition, the classical choking phenomenon can be captured at the superficial gas velocity slightly lower than the correlated transport velocity.

  5. Assessment of sorbent reactivation by water hydration for fluidized bed combustion application

    SciTech Connect

    Fabio Montagnaro; Piero Salatino; Fabrizio Scala; Yinghai Wu; Edward J. Anthony; Lufei Jia

    2006-06-15

    Disposal of fluidized bed combustion (FBC) solid residues currently represents one of the major issues in FBC design and operation, and contributes significantly to its operating cost. This issue has triggered research activities on the enhancement of sorbent utilization for in situ sulfur removal. The present study addresses the effectiveness of the reactivation by liquid water hydration of FB spent sorbents. Two materials are considered in the study, namely the bottom ash from the operation of a full-scale utility FB boiler and the raw commercial limestone used in the same boiler. Hydration-reactivation tests were carried out at temperatures of 40{sup o}C and 80{sup o}C and for curing times ranging from 15 minutes to 2d, depending on the sample. The influence of hydration conditions on the enhancement of sulfur utilization has been assessed. A combination of methods has been used to characterize the properties of liquid water-hydrated materials

  6. Constructive features, operation and sizing of fluidized bed gasifiers for biomass

    SciTech Connect

    Gomes, E.O.; Lora, E.S.; Cortez, L.A.B.

    1995-11-01

    In this paper a few considerations about constructive features, operation and sizing of biomass atmospheric fluidized bed gasifiers are presented. The analysis is carried out on the base of papers and reports on different authors, and also based on the own authors` experience. The state-of-the-art of this technology is presented, as well as the main problems to solve for its wide industrial application. Successful commercial plants are mentioned. A method to calculate main design parameters using recommended values for the air factor, gas superficial velocity and bed temperature is given. The results are the gas, air and biomass flows, the reactor inner diameter and the expanded bed height. Calculations for three different biomass (sugarcane trash and bagasse, and rice husk) are presented.

  7. Latest Evolution of Oxy-Fuel Combustion Technology in Circulating Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Zhao, C. S.; Duan, L. B.; Chen, X. P.; Liang, C.

    O2/CO2 combustion technology is considered as one of the most promising method to mitigate the greenhouse effect, and the O2/CO2 CFB combustion technology which combines O2/CO2 combustion technology with circulating fluidized bed (CFB) combustion technology will extend both their advantages. The latest research findings on O2/CO2 CFB combustion technology are reviewed, the combustion and pollutant emission characteristics are expatiated, its effects on the boiler design are analyzed, the techno-economic assessment are reported and the key issues are indicated in the paper. O2/CO2 CFB combustion technology has no insolvable bottleneck in its development and due to its economic superiority; it is one of the most important clean coal technologies.

  8. An approach for modeling thermal destruction of hazardous wastes in circulating fluidized bed incinerator.

    PubMed

    Patil, M P; Sonolikar, R L

    2008-10-01

    This paper presents a detailed computational fluid dynamics (CFD) based approach for modeling thermal destruction of hazardous wastes in a circulating fluidized bed (CFB) incinerator. The model is based on Eular - Lagrangian approach in which gas phase (continuous phase) is treated in a Eularian reference frame, whereas the waste particulate (dispersed phase) is treated in a Lagrangian reference frame. The reaction chemistry hasbeen modeled through a mixture fraction/ PDF approach. The conservation equations for mass, momentum, energy, mixture fraction and other closure equations have been solved using a general purpose CFD code FLUENT4.5. Afinite volume method on a structured grid has been used for solution of governing equations. The model provides detailed information on the hydrodynamics (gas velocity, particulate trajectories), gas composition (CO, CO2, O2) and temperature inside the riser. The model also allows different operating scenarios to be examined in an efficient manner. PMID:19697764

  9. Radioactive Demonstrations Of Fluidized Bed Steam Reforming (FBSR) With Hanford Low Activity Wastes

    SciTech Connect

    Jantzen, C. M.; Crawford, C. L.; Burket, P. R.; Bannochie, C. J.; Daniel, W. G.; Nash, C. A.; Cozzi, A. D.; Herman, C. C.

    2012-10-22

    Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) are being evaluated. One immobilization technology being considered is Fluidized Bed Steam Reforming (FBSR) which offers a low temperature (700-750?C) continuous method by which wastes high in organics, nitrates, sulfates/sulfides, or other aqueous components may be processed into a crystalline ceramic (mineral) waste form. The granular waste form produced by co-processing the waste with kaolin clay has been shown to be as durable as LAW glass. The FBSR granular product will be monolithed into a final waste form. The granular component is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals such as sodalite. Production of the FBSR mineral product has been demonstrated both at the industrial, engineering, pilot, and laboratory scales on simulants. Radioactive testing at SRNL commenced in late 2010 to demonstrate the technology on radioactive LAW streams which is the focus of this study.

  10. Fluidized-Bed Waste-Heat Recovery System development. Semiannual report, February 1-July 31, 1982

    SciTech Connect

    Cole, W. E.; DeSaro, R.; Griffith, J.; Joshi, C.

    1982-08-01

    The Fluidized-Bed Waste-Heat Recovery (FBWHR) System is designed to preheat this combustion air using the heat available in dirty flue gas streams. In this system, a recirculating medium is heated by the flue gas in a fluidized bed. The hot medium is then removed from the bed and placed in a second fluidized bed where it is fluidized by the combustion air. Through this process, the combustion air is heated. The cooled medium is then returned to the first bed. Initial development of this concept is for the aluminum smelting industry.

  11. The research on the fragmentation of coal particles in a fluidized bed

    SciTech Connect

    Zhang, H.; Heidbrink, J.; Cen, K.; Ni, M.; Yan, J.

    1995-12-31

    This paper reports the determination of fragmentation of coal particles in a fluidized bed, and the quantitative index put forward to describe the fragmentation of coal particles in the fluidized bed. The influences of a variety of factors such as bed temperature, the time the coal stays in the fluidized bed, size of coal, coal rank and fluidizing medium on the index of the fragmentation of coal were studied at Zhejiang University. From the research results, one can draw a conclusion: the fragmentation of coal particles has different characteristics for varieties of coal ranks, and the main reasons for the fragmentation of coal particles are the first class fragmentation and the heat stress.

  12. Three-dimensional hydrodynamic and erosion modeling of fluidized beds using kinetic theory

    SciTech Connect

    Ding, J.; Lyczkowski, R.W. ); Burge, S.W. . Research Center)

    1992-05-01

    Three-dimensional hydrodynamic models for gas-solids flow are developed and used to compute bubble and solids motion in rectangular fluidized beds. Our computed results demonstrate the significance and necessity for three-dimensional models of hydrodynamics and erosion in fluidized-bed combustors. A kinetic theory model for erosion using Finnie's single-particle ductile erosion model was used to compute erosion in a rectangular fluidized bed containing a single tube. Comparison of two-dimensional and three-dimensional computed hydrodynamics, erosion rates, and patterns clearly show the superiority of three-dimensional modeling.

  13. Three-dimensional hydrodynamic and erosion modeling of fluidized beds using kinetic theory

    SciTech Connect

    Ding, J.; Lyczkowski, R.W.; Burge, S.W.

    1992-05-01

    Three-dimensional hydrodynamic models for gas-solids flow are developed and used to compute bubble and solids motion in rectangular fluidized beds. Our computed results demonstrate the significance and necessity for three-dimensional models of hydrodynamics and erosion in fluidized-bed combustors. A kinetic theory model for erosion using Finnie`s single-particle ductile erosion model was used to compute erosion in a rectangular fluidized bed containing a single tube. Comparison of two-dimensional and three-dimensional computed hydrodynamics, erosion rates, and patterns clearly show the superiority of three-dimensional modeling.

  14. Electrochemical struvite precipitation from digestate with a fluidized bed cathode microbial electrolysis cell.

    PubMed

    Cusick, Roland D; Ullery, Mark L; Dempsey, Brian A; Logan, Bruce E

    2014-05-01

    Microbial electrolysis cells (MECs) can be used to simultaneously convert wastewater organics to hydrogen and precipitate struvite, but scale formation at the cathode surface can block catalytic active sites and limit extended operation. To promote bulk phase struvite precipitation and minimize cathode scaling, a two-chamber MEC was designed with a fluidized bed to produce suspended particles and inhibit scale formation on the cathode surface. MEC operation elevated the cathode pH to between 8.3 and 8.7 under continuous flow conditions. Soluble phosphorus removal using digester effluent ranged from 70 to 85% with current generation, compared to 10-20% for the control (open circuit conditions). At low current densities (≤2 mA/m(2)), scouring of the cathode by fluidized particles prevented scale accumulation over a period of 8 days. There was nearly identical removal of soluble phosphorus and magnesium from solution, and an equimolar composition in the collected solids, supporting phosphorus removal by struvite formation. At an applied voltage of 1.0 V, energy consumption from the power supply and pumping (0.2 Wh/L, 7.5 Wh/g-P) was significantly less than that needed by other struvite formation methods based on pH adjustment such as aeration and NaOH addition. In the anode chamber, current generation led to COD oxidation (1.1-2.1 g-COD/L-d) and ammonium removal (7-12 mM) from digestate amended with 1 g/L of sodium acetate. These results indicate that a fluidized bed cathode MEC is a promising method of sustainable electrochemical nutrient and energy recovery method for nutrient rich wastewaters. PMID:24583521

  15. Assembly-Controlled Permeability of Layer-by-Layer Polymeric Microcapsules Using a Tapered Fluidized Bed.

    PubMed

    Noi, Ka Fung; Roozmand, Ali; Björnmalm, Mattias; Richardson, Joseph J; Franks, George V; Caruso, Frank

    2015-12-23

    Nano- and microcapsules engineered through layer-by-layer (LbL) assembly are finding an increasingly large number of applications as catalysts, electrochemical biosensors, bioreactors, artificial cells and drug delivery vehicles. While centrifugation-based LbL assembly is the most common method for coating template particles and preparing capsules, it is a batch process and requires frequent intervention that renders the system challenging to automate and scale up. Here, we report the use of a tapered fluidized bed (TFB) for the preparation of multilayered polymer capsules. This is a significant improvement over our recent approach of fluidizing particles in cylindrical fluidized beds (CFB) for LbL assembly. We demonstrate that TFB is compatible with particles <3 μm in diameter (an order-of-magnitude improvement compared with CFB), which can be fluidized with minimal entrainment. Additionally, layering materials were expanded to include both electrostatic and hydrogen-bonding polymer pairs (e.g., poly(allylamine hydrochloride) (PAH) and poly(styrenesulfonate) (PSS), and thiol-modified poly(methacrylic acid) (PMASH) and poly(N-vinylpyrrolidone) (PVPON), respectively). Finally, differences between capsules prepared via centrifugation-based and TFB LbL assembly were investigated. The obtained TFB microcapsules demonstrate increased film thickness and roughness compared with those prepared using centrifugation-based LbL assembly. Furthermore, PMASH microcapsules exhibit lower swelling and permeability when prepared via TFB LbL assembly compared with centrifugation-based LbL assembly due to enhanced multilayer deposition, entanglement, and cross-linking. Therefore, polymeric capsules fabricated via TFB LbL assembly may be useful for encapsulation and retention of relatively low molecular weight (∼20 kDa) hydrophilic biomacromolecules to passively or responsively release the payload for drug delivery applications. PMID:26651354

  16. Numerical simulation of film coating process in a novel rotating fluidized bed.

    PubMed

    Nakamura, Hideya; Iwasaki, Tomohiro; Watano, Satoru

    2006-06-01

    In this study, numerical simulation of film coating process in a novel rotating fluidized bed (RFB) was conducted by using a Discrete Element Method (DEM)-Computational Fluid Dynamics (CFD) coupling model. Particle movements and fluid motions in a centrifugal force field were simulated at three-dimensional cylindrical coordinate, and this model was applied to film coating process. Film coating process in a RFB was numerically analyzed by using a simplified assumption that a particle was coated only when a particle existed within a spray zone. The experiments were also conducted and uniformity of sprayed material was evaluated by investigating color difference of the coated particles. As a result of the numerical simulation, three-dimensional bubble movements and particle circulation could be well simulated. In addition, mass of the sprayed material on a single particle in a RFB could be visualized by using our proposed model. The relationship between distribution of the sprayed material and the coating time was also analyzed. Calculated mass distributions of the sprayed material could be expressed by a normal distribution function, showing qualitative good agreement with the previous studies. Effect of the operating parameters, such as gas velocity and centrifugal acceleration, on the uniformity of the sprayed material was also investigated by both numerical and experimental approaches. Comparison of the coating process in a RFB with that in a conventional fluidized bed was also conducted by the numerical simulation. The result showed that uniformity of the sprayed material was greatly improved in a RFB due to the much smaller circulation time. PMID:16755055

  17. Performance of dye-affinity beads for aluminium removal in magnetically stabilized fluidized bed

    PubMed Central

    Yavuz, Handan; Say, Ridvan; Andaç, Müge; Bayraktar, Necmi; Denizli, Adil

    2004-01-01

    Background Aluminum has recently been recognized as a causative agent in dialysis encephalopathy, osteodystrophy, and microcytic anemia occurring in patients with chronic renal failure who undergo long-term hemodialysis. Only a small amount of Al(III) in dialysis solutions may give rise to these disorders. Methods Magnetic poly(2-hydroxyethyl methacrylate) (mPHEMA) beads in the size range of 80–120 μm were produced by free radical co-polymerization of HEMA and ethylene dimethacrylate (EDMA) in the presence of magnetite particles (Fe3O4). Then, metal complexing ligand alizarin yellow was covalently attached onto mPHEMA beads. Alizarin yellow loading was 208 μmol/g. These beads were used for the removal of Al(III) ions from tap and dialysis water in a magnetically stabilized fluidized bed. Results Al(III) adsorption capacity of the beads decreased with an increase in the flow-rate. The maximum Al(III) adsorption was observed at pH 5.0. Comparison of batch and magnetically stabilized fluidized bed (MSFB) maximum capacities determined using Langmuir isotherms showed that dynamic capacity (17.5 mg/g) was somewhat higher than the batch capacity (11.8 mg/g). The dissociation constants for Al(III) were determined using the Langmuir isotherm equation to be 27.3 mM (MSFB) and 6.7 mM (batch system), indicating medium affinity, which was typical for pseudospecific affinity ligands. Al(III) ions could be repeatedly adsorbed and desorbed with these beads without noticeable loss in their Al(III) adsorption capacity. Conclusions Adsorption of Al(III) demonstrate the affinity of magnetic dye-affinity beads. The MSFB experiments allowed us to conclude that this inexpensive sorbent system may be an important alternative to the existing adsorbents in the removal of aluminium. PMID:15329149

  18. Affinity separation in magnetically stabilized fluidized beds: synthesis and performance of packing materials

    SciTech Connect

    Lochmueller, C.H.; Wigman, L.S.

    1987-11-01

    A magnetically stabilized fluidized-bed separator designed to test the use of pellicular, ferromagnetic affinity chromatography packing materials has been developed. A wire wound solenoid was used to produce the magnetic field. The ferromagnetic packing material is comprised of a magnetite-containing, polyurethane gel coated onto polystyrene beads. The gel contains free carboxyl groups. These were carbodiimide-coupled to soy trypsin inhibitor and the material used for trypsin purification. Narrow-band affinity chromatography was carried out in packed-bed, fluidized-bed, and magnetically stabilized, fluidized-bed separators. Pressure drop, capacity, dilution, and peak asymmetry were evaluated for each type of separator. The three types provide comparable efficiency but the fluidized separators exhibit a much lower pressure drop. As might be expected, fluidized-bed separators perform well for affinity chromatography (large k') but poorly for size exclusion chromatography.

  19. A novel fast mass transfer anaerobic inner loop fluidized bed biofilm reactor for PTA wastewater treatment.

    PubMed

    Chen, Yingwen; Zhao, Jinlong; Li, Kai; Xie, Shitao

    2016-01-01

    In this paper, a fast mass transfer anaerobic inner loop fluidized bed biofilm reactor (ILFBBR) was developed to improve purified terephthalic acid (PTA) wastewater treatment. The emphasis of this study was on the start-up mode of the anaerobic ILFBBR, the hydraulic loadings and the operation stability. The biological morphology of the anaerobic biofilm in the reactors was also analyzed. The anaerobic column could operate successfully for 46 days due to the pre-aerating process. The anaerobic column had the capacity to resist shock loadings and maintained a high stable chemical oxygen demand (COD) and terephthalic acid removal rates at a hydraulic retention time of 5-10 h, even under conditions of organic volumetric loadings as high as 28.8 kg COD·m(-3).d(-1). The scanning electron microscope analysis of the anaerobic carrier demonstrated that clusters of prokaryotes grew inside of pores and that the filaments generated by pre-aeration contributed to the anaerobic biofilm formation and stability. PMID:27642828

  20. A novel fast mass transfer anaerobic inner loop fluidized bed biofilm reactor for PTA wastewater treatment.

    PubMed

    Chen, Yingwen; Zhao, Jinlong; Li, Kai; Xie, Shitao

    2016-01-01

    In this paper, a fast mass transfer anaerobic inner loop fluidized bed biofilm reactor (ILFBBR) was developed to improve purified terephthalic acid (PTA) wastewater treatment. The emphasis of this study was on the start-up mode of the anaerobic ILFBBR, the hydraulic loadings and the operation stability. The biological morphology of the anaerobic biofilm in the reactors was also analyzed. The anaerobic column could operate successfully for 46 days due to the pre-aerating process. The anaerobic column had the capacity to resist shock loadings and maintained a high stable chemical oxygen demand (COD) and terephthalic acid removal rates at a hydraulic retention time of 5-10 h, even under conditions of organic volumetric loadings as high as 28.8 kg COD·m(-3).d(-1). The scanning electron microscope analysis of the anaerobic carrier demonstrated that clusters of prokaryotes grew inside of pores and that the filaments generated by pre-aeration contributed to the anaerobic biofilm formation and stability.

  1. Fluidized bed boiler at the Royal Alexandra Hospital for Children, Camperdown.

    PubMed

    Ellis, J W

    1985-03-01

    A fluidized bed boiler has been installed at the Royal Alexandra Hospital for Children, Camperdown, N.S.W. This paper describes the reasons for developing a project to demonstrate that a fluidized bed coal fire combustor can be incorporated with a modern packaged steam boiler. The boiler and combustor are of Australian design as suitable proven designs from overseas were not available. PMID:10271052

  2. Biological reduction of nitrate wastewater using fluidized-bed bioreactors

    SciTech Connect

    Walker, J.F. Jr.; Hancher, C.W.; Patton, B.D.; Kowalchuk, M.

    1981-01-01

    There are a number of nitrate-containing wastewater sources, as concentrated as 30 wt % NO/sub 3//sup -/ and as large as 2000 m/sup 3//d, in the nuclear fuel cycle as well as in many commercial processes such as fertilizer production, paper manufacturing, and metal finishing. These nitrate-containing wastewater sources can be successfully biologically denitrified to meet discharge standards in the range of 10 to 20 gN(NO/sub 3//sup -/)/m/sup 3/ by the use of a fluidized-bed bioreactor. The major strain of denitrification bacteria is Pseudomonas which was derived from garden soil. In the fluidized-bed bioreactor the bacteria are allowed to attach to 0.25 to 0.50-mm-diam coal particles, which are fluidized by the upward flow of influent wastewater. Maintaining the bacteria-to-coal weight ratio at approximately 1:10 results in a bioreactor bacteria loading of greater than 20,000 g/m/sup 3/. A description is given of the results of two biodenitrification R and D pilot plant programs based on the use of fluidized bioreactors capable of operating at nitrate levels up to 7000 g/m/sup 3/ and achieving denitrification rates as high as 80 gN(NO/sub 3//sup -/)/d per liter of empty bioreactor volume. The first of these pilot plant programs consisted of two 0.2-m-diam bioreactors, each with a height of 6.3 m and a volume of 208 liters, operating in series. The second pilot plant was used to determine the diameter dependence of the reactors by using a 0.5-m-diam reactor with a height of 6.3 m and a volume of 1200 liters. These pilot plants operated for a period of six months and two months respectively, while using both a synthetic waste and the actual waste from a gaseous diffusion plant operated by Goodyear Atomic Corporation.

  3. Bubbling fluidized bed retrofit with modern design tools

    SciTech Connect

    Korhonen, S.; Jacobson, T.; Jaeaeskelaeinen, K.; Hulkkonen, S.

    1999-07-01

    Imatran Voima Oy (IVO) has experience of more than 10 years in the design, construction and operation of power plants utilizing fluidized bed boilers (BFB). This operating experience, together with active fuels testing and the development work of computer aided design tools, has offered IVO a good possibility for product development. The new product was demonstrated by converting an old grate fired boiler into BFB at IVO's Vanaja plant. This boiler conversion project and the computational fluid dynamics (CFD) based tool used in the design of the combustion will be presented. The results of the model verification will be described briefly. At the Vanaja plant, a 60 MW{sub coal} fired grate boiler built in the early 1950s was converted to BFB in 1997. The old chain grate was removed and replaced with a fluidized bed with appropriate fluidization air and biofuel feeding systems. The automation system was also modernized. The primary fuel was changed to peat, whereas coal remained as secondary fuel together with natural gas and biofuels. IVO has long tradition in the computational fluid dynamics (CFD) aided engineering of combustion processes. Since 1990, Ardemus, a CFD based combustion modeling package has been applied for pulverized coal combustion. Recently Ardemus has also been applied to the simulation of the freeboard of BFB. The development work is still going on concerning the bed behavior and emission formation description. In the retrofit project, the change of the fuel and the combustion technology were analyzed with the Ardemus model. Because of the shortness of the furnace, the focus in the design process was laid on the optimization of air staging and adequate mixing of combustion air and fuel. The effect of the modification on the operating conditions of the turbine plant was calculated with a process simulator. The design was completed by cold model tests. The modified boiler was commissioned successfully at the beginning of 1998, which is the most

  4. A fluidized bed selective emitter system driven by a non-premixed burner

    NASA Astrophysics Data System (ADS)

    Ortabasi, U.; Lund, K. O.; Seshadri, K.

    1996-02-01

    One of the key priorities in the development of Thermophotovoltaic power technology is a highly efficient heat-source/emitter system that is robust and stable. This paper describes a tightly coupled burner/selective emitter combination that integrates two novel concepts that are now under development: A fluidized bed emitter that consists of hollow, submillimeter spheres as the sources of radiant energy and a non-premixed, self regulating burner. The rationale behind the proposed system is to combine the unique intrinsic features of both concepts to provide the TPV community with an enabling technology. The fluidized bed provides excellent heat transfer, temperature uniformity, high radiant power density, reduced substrate and combustion background, robustness, thermal shock resistance, minimal contamination, and long operational life. The paper discusses a fluidized bed system that consists of selectively emitting, hollow Ho-YAG spheres with 500 micron diameter and 10-100 micron shell thickness operating at 1500 K. Key issues related to heat transfer and radiation transport in the fluidized bed are analyzed. The collective emitter efficiency and power density of a fluidized bed are discussed. The non-premixed burner achieves very high temperatures, has a low emission in toxic byproducts, provides self regulating stability, eliminates flashback hazards, and is operable with hydrogen. The paper concludes with a description of a complete fluidized bed TPV system including an elliptic/parabolic transfer optics and a photovoltaic cavity converter that boosts the flux density received by the photovoltaic cells.

  5. Measurement of solids motion in gas-fluidized beds. Technical progress report, 1 October 1982-31 December 1982

    SciTech Connect

    Chen, M.M.; Chao, B.T.

    1982-01-01

    This technical progress report covers the progress made during the fifth quarter of the project entitled Measurements of Solids Motion in Gas Fluidized Beds under Grant No. DOE-F22-81PC40804 during the period 1 October through 31 December 1982. The research concerns the measurement of solids particle velocity distribution and residence time distribution using the Computer-Aided Particle Tracking Facility (CAPTF) at the University of Illinois at Urbana-Champaign. The experimental equipment and measuring methods used to determine particle size distribution and particle motion and the results obtained are presented.

  6. Process simulation of a circulating fluidized bed coal combustor

    SciTech Connect

    Legros, R.; Sotudeh-Gharebaagh, R.; Paris, J.; Chaouki, J.; Preto, F.

    1995-12-31

    The focus of this work is the development of a process simulator for a Circulating Fluidized Bed coal Combustor (CFBC). The development of a simple comprehensive model for coal combustion in a CFBC is based on existing work reported in the literature. The model combines the hydrodynamic features of a CFBC riser with the different reaction steps involved during coal combustion, including the sulphur capture by limestone particles. The commercial process simulation program ASPEN PLUS was chosen as a framework for the development of the CFBC process simulator. ASPEN PLUS has been widely accepted in the chemical industry as a design tool because of its ability to simulate various chemical processes, including power generation cycles. In ASPEN PLUS, several ideal chemical reactor models involving solids are available for simulation purposes. The CFBC process simulator is constructed using several ASPEN PLUS unit operation blocks. The information required for each block is obtained from the combustion and hydrodynamic models, which are inserted into the simulation flowsheet as subroutines or internal programs. The resulting CFBC process simulator is used to predict the performance of the CFBC pilot plant at Energy Research laboratories, CANMET in Ottawa.

  7. Pressurized fluidized-bed hydroretorting of Eastern oil shales

    SciTech Connect

    Roberts, M.J.; Mensinger, M.C.; Rue, D.M.; Lau, F.S.

    1992-09-01

    The Devonian oil shales of the Eastern United States are a significant domestic energy resource. The overall objective of the multi-year program, initiated in October 1987 by the US Department of Energy is to perform the research necessary to develop the pressurized fluidized-bed hydroretorting (PFH) process for producing oil from Eastern oil shales. The program also incorporates research on technologies in areas such as raw shale preparation, beneficiation, product separation and upgrading, and waste disposal that have the potential of improving the economics and/or environmental acceptability of recovering oil from oil shales using the PFH process. The program is divided into the following active tasks: Task 3. testing of process improvement concepts; Task 4. beneficiation research; Task 6. environmental data and mitigation analyses; Task 8. project management and reporting; and Task 9. information required for the National Environmental Policy Act. In order to accomplish all of the program objectives, the Institute of Gas Technology (IGT), the prime contractor, is working with four other institutions: The University of Alabama/Mineral Resources Institute (MRI), the University of Alabama College of Engineering (UA), University of Kentucky Center for Applied Energy Research (UK-CAER), and Tennessee Technological University (TTU). This report presents the work performed during the program quarter from June 1, 1992 through August 31, 1992.

  8. Characterization of fuels for atmospheric fluidized bed combustion

    SciTech Connect

    Daw, C.S. ); Rowley, D.R.; Perna, M.A. . Research Center); Stallings, J.W. ); Divilio, R.J. )

    1990-01-01

    The Electric Power Research Institute (EPRI) has sponsored a fuels characterization program for the past several years with the intention of assisting utilities and boiler manufacturers in evaluating fuel quality impact on atmospheric fluidized bed combustion (AFBC) performance. The goal has been to provide an improved framework for making fuel switching decisions and consolidating operating experience. Results from this program include a set of bench-scale testing procedures, a fuel characterization data base, and a performance simulation model that links fuel characteristics to combustion performance. This paper reviews the major results of the fuels characterization program. The testing procedures, data base, and performance simulation models are briefly described and their application illustrated with examples. Performance predictions for the B W 1-ft{sup 2} bench-scale AFBC and the Tennessee Valley Authority (TVA) 20 MW(e) AFBC Pilot Plant are compared with actual test data. The relationship of coal rank to combustion is discussed. 11 refs., 12 figs., 5 tabs.

  9. FLUIDIZED BED STEAM REFORMING ENABLING ORGANIC HIGH LEVEL WASTE DISPOSAL

    SciTech Connect

    Williams, M

    2008-05-09

    Waste streams planned for generation by the Global Nuclear Energy Partnership (GNEP) and existing radioactive High Level Waste (HLW) streams containing organic compounds such as the Tank 48H waste stream at Savannah River Site have completed simulant and radioactive testing, respectfully, by Savannah River National Laboratory (SRNL). GNEP waste streams will include up to 53 wt% organic compounds and nitrates up to 56 wt%. Decomposition of high nitrate streams requires reducing conditions, e.g. provided by organic additives such as sugar or coal, to reduce NOX in the off-gas to N2 to meet Clean Air Act (CAA) standards during processing. Thus, organics will be present during the waste form stabilization process regardless of the GNEP processes utilized and exists in some of the high level radioactive waste tanks at Savannah River Site and Hanford Tank Farms, e.g. organics in the feed or organics used for nitrate destruction. Waste streams containing high organic concentrations cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by pretreatment. The alternative waste stabilization pretreatment process of Fluidized Bed Steam Reforming (FBSR) operates at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). The FBSR process has been demonstrated on GNEP simulated waste and radioactive waste containing high organics from Tank 48H to convert organics to CAA compliant gases, create no secondary liquid waste streams and create a stable mineral waste form.

  10. Circulating fluidized-bed boiler makes inroads for waste recycling

    SciTech Connect

    1995-09-01

    Circulating fluidized-bed (CFB) boilers have ben used for years in Scandinavia to burn refuse-derived fuel (RDF). Now, Foster Wheeler Power Systems, Inc., (Clinton, N.J.) is bringing the technology to the US. Touted as the world`s largest waste-to-energy plant to use CFB technology, the Robbins (III.) Resource Recovery Facility will have the capacity to process 1,600 tons/d of municipal solid waste (MSW) when it begins operation in early 1997. The facility will have two materials-separation and RDF-processing trains, each with dual trommel screens, magnetic and eddy current separators, and shredders. About 25% of the incoming MSW will be sorted and removed for recycling, while 75% of it will be turned into fuel, with a heat value of roughly 6,170 btu/lb. Once burned in the twin CFB boilers the resulting steam will be routed through a single turbine generator to produce 50,000 mW of electric power.

  11. Pneumatic jet-control valve for dual circulating fluidized beds

    NASA Astrophysics Data System (ADS)

    Jiang, Haibo; Dong, Pengfei; Zhu, Zhiping; Wang, Kun; Zhang, Yukui; Lu, Qinggang

    2015-11-01

    With the rapid development of circulating fluidized bed (CFB) technology in different fields, the disadvantages of conventional non-mechanical valves are becoming more apparent, and they are not suitable to be used in complex CFB systems. In this paper, a novel non-mechanical valve named the jet-control valve is presented which can avoid the fluidization of solid particles. The feasibility and performance characteristics of the new valve are investigated with a cold-model dual CFB. The results show that compared with the conventional non-mechanical valve, the jet-control valve can transfer solid particles steadily over a larger range, prevent artesian flow, and improve the leakage characteristics. The effects of the operating parameters and structural parameters on the minimum aeration velocity, solid flow rate, and maximum solid flow rate are studied. A two-valve model is proposed to explain the transport capacity of the valve for one jet pipe. A semi-theoretical expression is obtained based on the experimental data with a maximum deviation of 30% providing useful guide for scaling-up the design.

  12. Sulfide oxidation in fluidized bed bioreactor using nylon support material.

    PubMed

    Midha, Varsha; Jha, M K; Dey, Apurba

    2012-01-01

    A continuous fluidized bed bioreactor (FBBR) with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25, 50 and 75 min and upflow velocity of 14, 17 and 20 m/hr. The effects of upflow velocity, hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model. Mixed culture obtained from the activated sludge, taken from tannery effluent treatment plant, was used as a source for microorganisms. The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3, respectively. Experiments were carried out in the reactor at a temperature of (30 +/- 2) degrees C, at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles. Biofilm thickness reached (42 +/- 3) microm after 15 days from reactor start-up. The sulfide oxidation, sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities. The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times. Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate. The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.

  13. Capacitance-level/density monitor for fluidized-bed combustor

    DOEpatents

    Fasching, George E.; Utt, Carroll E.

    1982-01-01

    A multiple segment three-terminal type capacitance probe with segment selection, capacitance detection and compensation circuitry and read-out control for level/density measurements in a fluidized-bed vessel is provided. The probe is driven at a high excitation frequency of up to 50 kHz to sense quadrature (capacitive) current related to probe/vessel capacitance while being relatively insensitive to the resistance current component. Compensation circuitry is provided for generating a negative current of equal magnitude to cancel out only the resistive component current. Clock-operated control circuitry separately selects the probe segments in a predetermined order for detecting and storing this capacitance measurement. The selected segment acts as a guarded electrode and is connected to the read-out circuitry while all unselected segments are connected to the probe body, which together form the probe guard electrode. The selected probe segment capacitance component signal is directed to a corresponding segment channel sample and hold circuit dedicated to that segment to store the signal derived from that segment. This provides parallel outputs for display, computer input, etc., for the detected capacitance values. The rate of segment sampling may be varied to either monitor the dynamic density profile of the bed (high sampling rate) or monitor average bed characteristics (slower sampling rate).

  14. Testing of Illinois coal in a circulating fluidized bed

    SciTech Connect

    Flynn, T.J.; Hooper, M.P.; Ilan, R. . Research Center)

    1990-01-01

    Illinois No. 6 mine-run coal, washed coal, and coal-cleaning waste by-products from a Murdock, Illinois, mine were tested in a 30-foot-tall, small-scale (1 million-Btu/hr), circulating, fluidized-bed combustor (CFBC) located at the Babcock Wilcox Alliance (B W) (Ohio) Research Center. The goal of the project was to promote the use of Illinois coal by demonstrating that the three fuels could be combusted efficiently and in an environmentally acceptable manner. The ability to burn mine-run coal could justify eliminating the coal-cleaning step for new CFBC units. A positive demonstration with the cleaning-waste by-products would reduce the cost for fuel for all users of Illinois washed coal by reducing waste disposal costs. In addition, the existing stockpiles of coal wastes could be removed. The project was co-funded by the Illinois Center for Research on Sulfur in Coal, the Electric Power Research Institute (EPRI), and B W. The combustion efficiencies of all three fuels were similar to efficiencies obtained with other bituminous coals tested on the unit. All three fuels could be combusted with acceptable CO, SO{sub 2}, and NO{sub x} emissions. The agglomeration that occurred with the mine-run coal was alleviated by increasing the bed drain rate and utilizing periodic bed dumps to remove small agglomerates. 7 figs., 7 tabs.

  15. Combustion of oil palm solid wastes in fluidized bed combustor

    SciTech Connect

    Shamsuddin, A.H.; Sopian, K.

    1995-12-31

    The palm oil industry of Malaysia is the largest in the world producing about 55% of the world production. The industry has approximately 270 mills throughout the country with processing sizes ranging from 10 tonnes/hour to 120 tonnes/hour. All mills produce solid wastes, about 50% of the fresh fruit bunches in terms of weight. The solid wastes produced are in the form of empty fruit bunches, fibers and shells. These wastes have high energy value, ranging from 14 to 18 MJ/kg. The industry is currently self-sufficient in terms of energy. Fibers and shell wastes are being used as boiler fuel to raise steam for electrical power production and process steam. However, the combustion technology currently being employed is obsolete with low efficiency and polluting. A fluidized bed combustor pilot plant is designed and constructed at Combustion Research Laboratory, Universiti Kebangsaan Malaysia. The combustor is made up of 600 mm {times} 900 mm rectangular bed filled with sand up to 400 mm height, static. A bank of heat transfer tubes is imbedded in the bed, designed to absorb 50% of heat released by the fuel in the bed. The remaining heat is transferred in tubes placed on the wall of the freeboard area. Experimental studies were carried out in the pilot plant using palm oil solid wastes. The combustion temperatures were maintained in the range 800--900 C. The performance of the combustor was evaluated in terms of combustion and boiler efficiencies and flue gas emissions monitored.

  16. Oil shale loss from a laboratory fluidized bed

    SciTech Connect

    Taylor, R.W.; Beavers, P.L.

    1989-03-01

    The rate of loss of dust from a laboratory scale fluidized bed of Green River oil shale has been measured. The rate of loss of dust from raw shale in the bed was approximately 1%/min for the first few minutes, and then decreased. The loss rate for retorted or burnt shale was 5 to 10 times higher. The rate for retorted and burned shale were nearly the same. The time required for a 10 wt% loss of mass was approximately 3 min for processed shale and 1 hour for raw shale. Particles left in the bed during fluidization lost sharp corners, but kept the original elongation. Dust lost by the bed has a very wide range of sizes, and demonstrated a strong bimodal distribution of sizes. The bimodal distribution of particles is interpreted as resulting from two mechanisms of dust generation: fracture and wear. Fracture of large particles sometimes produced fragments which were small enough to be blown out of the bed. These fragments were much larger than the individual mineral grains in the shale. The fracture mechanism was dominant in the case of raw shale. Dust in the smaller particle-size range was generated by wear. Wear was the dominant mechanisms in the case of burned shale, whereas, for retorted shale, nearly equal amounts of dust were generated by each mechanism. 13 refs., 8 figs., 6 tabs.

  17. DURABILITY TESTING OF FLUIDIZED BED STEAM REFORMER (FBSR) WASTE FORMS

    SciTech Connect

    Jantzen, C

    2006-01-06

    Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of high sodium aqueous radioactive wastes. The addition of clay and a catalyst as co-reactants converts high sodium aqueous low activity wastes (LAW) such as those existing at the Hanford and Idaho DOE sites to a granular ''mineralized'' waste form that may be made into a monolith form if necessary. Simulant Hanford and Idaho high sodium wastes were processed in a pilot scale FBSR at Science Applications International Corporation (SAIC) Science and Technology Applications Research (STAR) facility in Idaho Falls, ID. Granular mineral waste forms were made from (1) a basic Hanford Envelope A low-activity waste (LAW) simulant and (2) an acidic INL simulant commonly referred to as sodium-bearing waste (SBW). The FBSR waste forms were characterized and the durability tested via ASTM C1285 (Product Consistency Test), the Environmental Protection Agency (EPA) Toxic Characteristic Leaching Procedure (TCLP), and the Single Pass Flow Through (SPFT) test. The durability of the FBSR waste form products was tested in order to compare the measured durability to previous FBSR waste form testing on Hanford Envelope C waste forms that were made by THOR Treatment Technologies (TTT) and to compare the FBSR durability to vitreous LAW waste forms, specifically the Hanford low activity waste (LAW) glass known as the Low-activity Reference Material (LRM). The durability of the FBSR waste form is comparable to that of the LRM glass for the test responses studied.

  18. Treating exhaust gas from a pressurized fluidized bed reaction system

    DOEpatents

    Isaksson, J.; Koskinen, J.

    1995-08-22

    Hot gases from a pressurized fluidized bed reactor system are purified. Under super atmospheric pressure conditions hot exhaust gases are passed through a particle separator, forming a filtrate cake on the surface of the separator, and a reducing agent--such as an NO{sub x} reducing agent (like ammonia)--is introduced into the exhaust gases just prior to or just after particle separation. The retention time of the introduced reducing agent is enhanced by providing a low gas velocity (e.g. about 1--20 cm/s) during passage of the gas through the filtrate cake while at super atmospheric pressure. Separation takes place within a distinct pressure vessel, the interior of which is at a pressure of about 2--100 bar, and introduction of reducing agent can take place at multiple locations (one associated with each filter element in the pressure vessel), or at one or more locations just prior to passage of clean gas out of the pressure vessel (typically passed to a turbine). 8 figs.

  19. Treating exhaust gas from a pressurized fluidized bed reaction system

    SciTech Connect

    Isaksson, Juhani; Koskinen, Jari

    1995-01-01

    Hot gases from a pressurized fluidized bed reactor system are purified. Under superatmospheric pressure conditions hot exhaust gases are passed through a particle separator, forming a flitrate cake on the surface of the separator, and a reducing agent--such as an NO.sub.x reducing agent (like ammonia), is introduced into the exhaust gases just prior to or just after particle separation. The retention time of the introduced reducing agent is enhanced by providing a low gas velocity (e.g. about 1-20 cm/s) during passage of the gas through the filtrate cake while at superatmospheric pressure. Separation takes place within a distinct pressure vessel the interior of which is at a pressure of about 2-100 bar, and-introduction of reducing agent can take place at multiple locations (one associated with each filter element in the pressure vessel), or at one or more locations just prior to passage of clean gas out of the pressure vessel (typically passed to a turbine).

  20. Direct combustion of olive cake using fluidized bed combustor

    SciTech Connect

    Khraisha, Y.H.; Hamdan, M.A.; Qalalweh, H.S.

    1999-05-01

    A fluidized bed combustor of 0.146 m diameter and 1 m length was fabricated from stainless steel to burn olive cake. Initially, and in order to obtain fluidization, the system was operated under cold conditions using a sand with particle size in the range of 500 to 710 microns. The continuous combustion experiments were carried out under controlled conditions, such that the effects of bed temperature, olive cake feed rate, fluidization velocity, and particle size on combustion efficiency and flue gas composition were investigated. It was found that the combustion efficiency decreases with the bed temperature, fluidization velocity, and the feed rate, while it increases with the particle size used. Further, the gas products analysis carried out using a gas chromatography analyzer have shown a nonmeasured amount of SO{sub 2}, and small amounts of CO. Finally, the temperature distribution along the bed indicated that the temperature throughout the bed is fairly uniform, demonstrating a good mixing of reactants, which is important for efficient combustion.

  1. Bubbles trapped in a fluidized bed: Trajectories and contact area

    NASA Astrophysics Data System (ADS)

    Poryles, Raphaël; Vidal, Valérie; Varas, Germán

    2016-03-01

    This work investigates the dynamics of bubbles in a confined, immersed granular layer submitted to an ascending gas flow. In the stationary regime, a central fluidized zone of parabolic shape is observed, and the bubbles follow different dynamics: either the bubbles are initially formed outside the fluidized zone and do not exhibit any significant motion over the experimental time or they are located inside the fluidized bed, where they are entrained downwards and are, finally, captured by the central air channel. The dependence of the air volume trapped inside the fluidized zone, the bubble size, and the three-phase contact area on the gas injection flow rate and grain diameter are quantified. We find that the volume fraction of air trapped inside the fluidized region is roughly constant and of the order of 2%-3% when the gas flow rate and the grain size are varied. Contrary to intuition, the gas-liquid-solid contact area, normalized by the air injected into the system, decreases when the flow rate is increased, which may have significant importance in industrial applications.

  2. Fluid dynamics of the freeboard in a fluidized bed reactor

    NASA Astrophysics Data System (ADS)

    Verloop, Willem Cornelis

    1994-05-01

    The present study focuses on the fluid dynamics of the gas-particle freeboard flow, whereas a subsequent study will cover the chemistry. The objective of the present thesis is to increase the insight in the physical processes that govern the freeboard particle flow. Special attention has to be paid to the lateral transport of particles and the often observed phenomenon of a downflowing wall layer of solids, which has not been explained satisfactorily up to now. In order to achieve this, detailed experiments have to be performed which provide data on the local flow structure. In addition, the freeboard flow has to be modeled at least two-dimensionally, incorporating the essential physical processes. The resulting model of the freeboard flow should firstly be capable of predicting the local properties of both the gas flow and the particle flow. This prediction has to serve as a basis for the subsequent modeling of the freeboard chemistry. Secondly, the model should serve as a basis for studying the consequences of the scaling up a fluidized bed installation from lab scale to industrial size.

  3. Fluidized bed gasification of waste-derived fuels

    SciTech Connect

    Arena, Umberto; Zaccariello, Lucio; Mastellone, Maria Laura

    2010-07-15

    Five alternative waste-derived fuels obtained from municipal solid waste and different post-consumer packaging were fed in a pilot-scale bubbling fluidized bed gasifier, having a maximum feeding capacity of 100 kg/h. The experimental runs utilized beds of natural olivine, quartz sand or dolomite, fluidized by air, and were carried out under various values of equivalence ratio. The process resulted technically feasible with all the materials tested. The olivine, a neo-silicate of Fe and Mg with an olive-green colour, has proven to be a good candidate to act as a bed catalyst for tar removal during gasification of polyolefin plastic wastes. Thanks to its catalytic activity it is possible to obtain very high fractions of hydrogen in the syngas (between 20% and 30%), even using air as the gasifying agent, i.e. in the most favourable economical conditions and with the simplest plant and reactor configuration. The catalytic activity of olivine was instead reduced or completely inhibited when waste-derived fuels from municipal solid wastes and aggregates of different post-consumer plastic packagings were fed. Anyhow, these materials have given acceptable performance, yielding a syngas of sufficient quality for energy applications after an adequate downstream cleaning.

  4. Modern fluidized bed combustion in Ostrava-Karvina cogeneration plants

    SciTech Connect

    Mazac, V.; Novacek, A.; Volny, J.

    1995-12-01

    The contemporary situation of our environment claims the sensitive approach to solving effective conversion of energy. Limited supplies of noble fuels and their prices evoke the need to use new combustion technologies of accessible fuels in given region without negative ecological influences. Energoproject participates in the preparation of the two projects in Ostrava-Karvin{acute a} black coal field in Czech Republic. The most effective usage of fuel energy is the combined of electricity and heat. If this physical principle is supported by a pressurized fluidized bed combustion (PFBC) one obtains a high electricity/heat ratio integrated steam-gas cycle on the basis of solid fuel. Cogeneration plant Toebovice is the dominant source (600 MW{sub th}) of Ostrava district heating system (1100 MW{sub th}). The high utilization of the installed output and utilization of the clean, compact and efficient of the PFBC technology is the principal but not the single reason for the selection of the Toebovice power plant as the first cogeneration plant for installation of the PFBC in Czech Republic. The boiler will burn black coal from the neighboring coal basin.

  5. Detoxification of ashes from a fluidized bed waste incinerator.

    PubMed

    Yu, Jie; Qiao, Yu; Sun, Lushi; Jin, Limei; Wang, Wenxia; Ma, Chuan

    2015-09-01

    This paper was to test and control the toxicity of bottom and fly ashes from a circulated fluidized bed (CFB) incinerator. Bottom and fly ashes were firstly subject to TCLP test. Even though leachates of most particle size of bottom ash were below regulatory limit, the leachates of finer bottom ash may exceed the regulatory limit. Therefore, finer bottom ash should be separated and treated before landfilled directly or used as cement replacement. Due to high amounts of leached heavy metals, thermal treatment of fly ash was carried out to remove heavy metals. The influence of temperature, residence time, metal chloride and gas velocity were studied. In all conditions, Cd can be well removed. Pb can be almost completely removed with MgCl2 addition at 1000°C in 1h. The removal of Zn and Cu was accelerated significantly by MgCl2 and higher temperature separately. At optimum conditions, more than 90% of Cu and 95% of Zn could be removed, while a maximum 20% of Cr was removed due to the existence or formation of CaCr2O4, MgCr2O4 and K2Cr2O4 in raw or treated fly ashes. PMID:25973859

  6. Process development and modeling of fluidized-bed reactor with coimmobilized biocatalyst for fuel ethanol production

    NASA Astrophysics Data System (ADS)

    Sun, May Yongmei

    was 25--44g/L-hr (based on reactor volume), the average yield was 0.45 g ethanol/g starch, the biocatalyst retained physical integrity and contamination did not affect fermentation. For the Z. mobilis system the maximum volumetric productivity was 38 g ethanol/L-h, the average yield was 0.51 g ethanol/g starch and the FBR was successfully operated for almost one month. In order to develop, scale-up and economically evaluate this system more efficiently, a predictive mathematical model that is based on fundamental principles was developed and verified. This model includes kinetics of reactions, transport phenomena of the reactant and product by diffusion within the biocatalyst bead, and the hydrodynamics of the three phase fluidized bed. The co-immobilized biocatalyst involves a consecutive reaction mechanism The mathematical descriptions of the effectiveness factors of reactant and the intermediate product were developed. Hydrodynamic literature correlations were used to develop the dispersion coefficient and gas, liquid, and solid holdup. The solutions of coupled non-linear second order equations for biocatalyst bead and reactor together with the boundary conditions were solved numerically. This model gives considerable information about the system, such as concentration profiles inside both the beads and column, flow rate and feed concentration influences on productivity and phase hold up, and the influence of enzyme and cell mass loading in the catalyst. This model is generic in nature such that it can be easily applied to a diverse set of applications and operating conditions.

  7. Fluidized-bed adsorption bioreactor for the treatment of groundwater contaminated with solvents at low concentration

    SciTech Connect

    Miyares, P.H.; Teeter, C.V.; Martel, C.J.

    1999-01-01

    Volatile organic compounds (VOCs) are a major source of water contamination in the US. They pose a threat to the environment and are a potential hazard to human health. Trichloroethylene (TCE) is the most common of these pollutants. TCE is usually remediated through pumping and treating it, using either air stripping or granular activated carbon. Bioremediation is an alternative treatment that uses microbes to convert hazardous substances into nonhazardous compounds. A fluidized bed adsorption bioreactor is examined here for the treatment of groundwater contaminated at low concentrations. This pilot study showed that the packed adsorbent bed could be loaded in approximately 36 hours at a flow rate of 120 mL/min. The remediation phase of the process took approximately 13 days. The reduction in the TCE concentration in the sorbent during each round indicated that it was being remediated by the microbiological process. Areas that need to be improved are the rate of remediation and the loading capacity of the adsorption beds. Currently, each complete cycle of loading and remediating requires 2 weeks while only mineralizing 58 mg of TCE per column.

  8. Pressurized fluidized-bed hydroretorting of eastern oil shales. Progress report, September 1992--November 1992

    SciTech Connect

    Roberts, M.J.; Mensinger, M.C.; Rue, D.M.; Lau, F.S.

    1992-12-01

    This report presents the work performed during the program quarter from September 1, 1992 though November 30, 1992. The Institute of Gas Technology (IGT) is the prime contractor for the program extension to develop the Pressurized Fluidized-Bed Hydroretorting II system technology. Four institutions are working with IGT as subcontractors. Task achievements are discussed for the following active tasks of the program: Subtask 3.7 innovative reactor concept testing; Subtask 3.9 catalytic hydroretorting; Subtask 3.10 autocatalysis in hydroretorting; Subtask 3.11 shale oil upgrading and evaluation; Subtask 4.1.3 stirred ball mill grinding; Subtask 4.1.5 alternative technology evaluation; Subtask 4.1.6 ultrafine size separation; Subtask 4.2.1 column flotation tests; Subtask 4.4 integrated grinding and flotation; Subtask 4.7 economic analysis; Subtask 6.2.2 wastewater treatability; Subtask 6.2.3 waste management facility conceptual design; and Subtask 8 project management and reporting.

  9. Ethanol production from dry-mill corn starch in a fluidized-bed bioreactor

    SciTech Connect

    Krishnan, M.S.; Nghiem, N.P.; Davison, B.H.

    1998-08-01

    The development of a high-rate process for the production of fuel ethanol from dry-mill corn starch using fluidized-bed bioreactor (FBR) technology is discussed. Experiments were conducted in a laboratory scale FBR using immobilized biocatalysts. Two ethanol production process designs were considered in this study. In the first design, simultaneous saccharification and fermentation was performed at 35 C using {kappa}-carageenan beads (1.5 mm to 1.5 mm in diameter) of co-immobilized glucoamylase and Zymomonas mobilis. For dextrin feed concentration of 100 g/L, the single-pass conversion ranged from 54% to 89%. Ethanol concentrations of 23 to 36 g/L were obtained at volumetric productivities of 9 to 15 g/L-h. No accumulation of glucose was observed, indicating that saccharification was the rate-limiting step. In the second design, saccharification and fermentation were carried out sequentially. In the first stage, solutions of 150 to 160 g/L dextrins were pumped through an immobilized glucoamylase packed column maintained at 55 C. Greater than 95% conversion was obtained at a residence time of 1 h, giving a product of 165 to 170 g glucose/L. In the second stage, these glucose solutions were fed to the FBR containing Z. mobilis immobilized in {kappa}-carageenan beads. At a residence time of 2 h, 94% conversion and ethanol concentration of 70 g/L was achieved, giving an overall productivity of 23 g/L-h.

  10. Simultaneous saccharification and fermentation of starch for ethanol production in a fluidized-bed reactor

    SciTech Connect

    Nghiem, N.P.; Davison, B.H.; Sun, M.Y.; Bienkowski, P.R.

    1997-12-31

    Immobilized Zymomonas mobilis has been used to produce ethanol from glucose in fluidized-bed reactor at volumetric productivity as high as 60 g/L-h and theoretical yield. This research was extended to study the production of ethanol from starch. The bacteria were co-immobilized with an industrial glucoamylase within small uniform beads (2 to 2.5 mm diameter) of k-carrageenan. The reactor was a glass column of 1.2 m in length with a uniform 2.54 cm diameter. The substrate included a commercially available maltodextrin and a soluble starch solution which was produced by hydrolysis of ground corn meals using amylase under the conditions commonly used in an industrial process. Light steep water was used as the complex nutrient source. Statistical experimental design was used to study the effects of substrate concentration and feed rate on ethanol yield and reactor productivity. The experiments were performed at 30{degrees}C and pH 5. The substrate concentration ranged from 93 to 2.7 g/L and the feed rates from 6.6 to 26.7 mL/min. The results of these studies will be discussed.

  11. Mineralogy and pore water chemistry of a boiler ash from a MSW fluidized-bed incinerator.

    PubMed

    Bodénan, F; Guyonnet, D; Piantone, P; Blanc, P

    2010-07-01

    This paper presents an investigation of the mineralogy and pore water chemistry of a boiler ash sampled from a municipal solid waste fluidized-bed incinerator, subject to 18 months of dynamic leaching in a large percolation column experiment. A particular focus is on the redox behaviour of Cr(VI) in relation to metal aluminium Al(0), as chromium may represent an environmental or health hazard. The leaching behaviour and interaction between Cr(VI) and Al(0) are interpreted on the basis of mineralogical evolutions observed over the 18-month period and of saturation indices calculated with the geochemical code PhreeqC and reviewed thermodynamic data. Results of mineralogical analyses show in particular the alteration of mineral phases during leaching (e.g. quartz and metal aluminium grains), while geochemical calculations suggest equilibria of percolating fluids with respect to specific mineral phases (e.g. monohydrocalcite and aluminium hydroxide). The combination of leaching data on a large scale and mineralogical analyses document the coupled leaching behaviour of aluminium and chromium, with chromium appearing in the pore fluids in its hexavalent and mobile state once metal aluminium is no longer available for chromium reduction.

  12. Fluidized bed reactor for the biological treatment of ion-exchange brine containing perchlorate and nitrate.

    PubMed

    Patel, A; Zuo, G; Lehman, S G; Badruzzaman, M; Clifford, D A; Roberts, D J

    2008-10-01

    The removal of perchlorate and nitrate from contaminated drinking water using regenerable ion-exchange processes produces a high salt brine (3-10% NaCl) laden with high concentrations of perchlorate and nitrate. This bench-scale research describes the operation of acetate-fed granular activated carbon (GAC) based fluidized bed reactors (FBR) for perchlorate-only, and combined nitrate and perchlorate removal from synthetic brine (6% NaCl). The GAC was inoculated with a salt-tolerant culture developed by the authors and used previously in batch systems. An FBR was an effective design for perchlorate reduction and exhibited first-order degradation kinetics with respect to perchlorate concentrations. Nitrate was also removed by the organisms in the column and had no negative effects on the removal of perchlorate using the FBR design. However, at higher concentrations of nitrate the FBR was more difficult to operate due to loss of carbon and biomass from the formation of nitrogen bubbles and the high recycle flow rates needed.

  13. Mineralogy and pore water chemistry of a boiler ash from a MSW fluidized-bed incinerator

    SciTech Connect

    Bodenan, F.; Guyonnet, D.; Piantone, P.; Blanc, P.

    2010-07-15

    This paper presents an investigation of the mineralogy and pore water chemistry of a boiler ash sampled from a municipal solid waste fluidized-bed incinerator, subject to 18 months of dynamic leaching in a large percolation column experiment. A particular focus is on the redox behaviour of Cr(VI) in relation to metal aluminium Al{sup 0}, as chromium may represent an environmental or health hazard. The leaching behaviour and interaction between Cr(VI) and Al{sup 0} are interpreted on the basis of mineralogical evolutions observed over the 18-month period and of saturation indices calculated with the geochemical code PhreeqC and reviewed thermodynamic data. Results of mineralogical analyses show in particular the alteration of mineral phases during leaching (e.g. quartz and metal aluminium grains), while geochemical calculations suggest equilibria of percolating fluids with respect to specific mineral phases (e.g. monohydrocalcite and aluminium hydroxide). The combination of leaching data on a large scale and mineralogical analyses document the coupled leaching behaviour of aluminium and chromium, with chromium appearing in the pore fluids in its hexavalent and mobile state once metal aluminium is no longer available for chromium reduction.

  14. Development of a simple fluidized-bed coal combustion model for the assessment of a pressurized fluidized-bed combustion system for electrical power generation

    SciTech Connect

    Saxena, S.C.; Turek, D.G.

    1980-07-01

    This report summarizes the state-of-the-art in the mathematical modeling of fluidized-bed coal combustors with the goal of evolving a general framework which will be appropriate for developing a system model for the fluidized-bed coal combustion and power generation technology. Consequently, no attempt is made to generate a functional model, but instead a very simple model is proposed as a first step. The model considers all the essential ingredients of coal combustion and sulfur absorption in fluidized-bed reactors. These are coal devolatilization, char combustion in a bed of dolomite or calcium carbonate, sulfur retention in the fluidized-bed elutriation from the bed, and heat removal by cooling tubes imbedded in the bed. The model is presented and a numerical scheme is proposed which will permit the calculation of bed temperature, coal combustion efficiency, sulfur retention, flue gas composition, and overflow from the bed. Numerical results are presented in which the dependence of the various combustion and operating parameters is examined.

  15. Integrated Use of Fluidized Bed Technology for Oil Production from Oil Shale

    NASA Astrophysics Data System (ADS)

    Siirde, Andres; Martins, Ants

    The plant unit which consists of a fluidized bed retort and CFB furnace for burning the by-products of retorting (semicoke and semicoke gas) is presented in this paper. The oil shale retort consists of a fast fluidized bed shaft, coarse semicoke bit, semicoke separation chamber and cyclone for the separation of fine semicoke particles. The crashed oil shale and hot ash from the CFB ash separator are fed concurrently into the fast fluidized bed shaft. For fluidizing the mixture of oil shale and hot ash particles, the recycle semicoke gas is used. The pyrolysis of oil shale begins in fluidized bed and is completed in the semicoke separation chamber. The coarse semicoke particles are separated from fluidized bed directly while the medium size particles are separated from the gases in the semicoke separation chamber and the finest semicoke particles in the cyclone. All the fractions of semicoke from the fluidized bed retort and semicoke gas from the oil fractionator are burnt in the CFB furnace. The semicoke ash is separated from flue gases in the CFB ash separator. A part of separated hot ash is fed into the fluidized bed retort as a solid heat carrier material and the rest into the furnace through the ash cooler or separated from the process. The retention of sulphur dioxide formed during the semicoke and semicoke gas combustion, is guaranteed for about 99 % due to the high CaO content in the semicoke ash and convenient temperature (about 850°C) in the CFB furnace. The described plant unit is useful for retorting oil shale and other solid hydrocarbon-containing fuels. The advantages of the present retorting process and system are: improved oil yield, greater throughput, lower retorting time, avoidance of moving parts in the retorting zones, reduced downtime, etc. A new plant unit for oil shale oil production has been elaborated and defended by the Estonian Utility Model EE 200700671 UI.

  16. DEVELOPMENT OF PRESSURIZED CIRCULATING FLUIDIZED BED PARTIAL GASIFICATION MODULE (PGM)

    SciTech Connect

    Unknown

    2001-07-10

    Foster Wheeler Development Corporation is working under DOE contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% while producing near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The unique aspect of the process is that it utilizes a pressurized circulating fluidized bed partial gasifier and does not attempt to consume the coal in a single step. To convert all the coal to syngas in a single step requires extremely high temperatures ({approx}2500 to 2800F) that melt and vaporize the coal and essentially drive all coal ash contaminants into the syngas. Since these contaminants can be corrosive to power generating equipment, the syngas must be cooled to near room temperature to enable a series of chemical processes to clean the syngas. Foster Wheeler's process operates at much lower temperatures that control/minimize the release of contaminants; this eliminates/minimizes the need for the expensive, complicated syngas heat exchangers and chemical cleanup systems typical of high temperature gasification. By performing the gasification in a circulating bed, a significant amount of syngas can still be produced despite the reduced temperature and the circulating bed allows easy scale up to large size plants. Rather than air, it can also operate with oxygen to facilitate

  17. Pressurized fluidized-bed hydroretorting of Eastern oil shales

    SciTech Connect

    Roberts, M.J.; Mensinger, M.C.; Rue, D.M.; Lau, F.S. ); Schultz, C.W. ); Parekh, B.K. ); Misra, M. ); Bonner, W.P. )

    1992-11-01

    The Devonian oil shales of the Eastern United States are a significant domestic energy resource. The overall objective of the multi-year program, initiated in October 1987 by the US Department of Energy is to perform the research necessary to develop the Pressurized Fluidized-Bed Hydroretorting (PFH) process for producing oil from Eastern oil shales. The program also incorporates research on technologies in areas such as raw shale preparation, beneficiation, product separation, and waste disposal that have the potential of improving the economics and/or environmental acceptability of recovering oil from oil shales using the PFH process. The results of the original 3-year program, which was concluded in May 1991, have been summarized in a four-volume final report published by IGT. DOE subsequently approved a 1-year extension to the program to further develop the PFH process specifically for application to beneficiated shale as feedstock. Studies have shown that beneficiated shale is the preferred feedstock for pressurized hydroretorting. The program extension is divided into the following active tasks. Task 3. testing of process improvement concepts; Task 4. beneficiation research; Task 5. operation of PFH on beneficiated shale; Task 6. environmental data and mitigation analyses; Task 7. sample procurement, preparation, and characterization; and Task 8. project management and reporting. In order to accomplish all the program objectives, the Institute of Gas Technology (IGT), the prime contractor, worked with four other institutions: the University of Alabama/Mineral Resources Institute (MRI), the University of Kentucky Center for Applied Energy Research (UK-CAER), the University of Nevada (UN) at Reno, and Tennessee Technological University (TTU). This report presents the work performed during the program extension from June 1, 1991 through May 31, 1992.

  18. Dynamic analysis of a circulating fluidized bed riser

    SciTech Connect

    Panday, Rupen; Shadle, Lawrence J.; Guenther, Chris

    2012-01-01

    A linear state model is proposed to analyze dynamic behavior of a circulating fluidized bed riser. Different operating regimes were attained with high density polyethylene beads at low and high system inventories. The riser was operated between the classical choking velocity and the upper transport velocity demarcating fast fluidized and transport regimes. At a given riser superficial gas velocity, the aerations fed at the standpipe were modulated resulting in a sinusoidal solids circulation rate that goes into the riser via L-valve. The state model was derived based on the mass balance equation in the riser. It treats the average solids fraction across the entire riser as a state variable. The total riser pressure drop was modeled using Newton’s second law of motion. The momentum balance equation involves contribution from the weight of solids and the wall friction caused by the solids to the riser pressure drop. The weight of solids utilizes the state variable and hence, the riser inventory could be easily calculated. The modeling problem boils down to estimating two parameters including solids friction coefficient and time constant of the riser. It has been shown that the wall friction force acts in the upward direction in fast fluidized regime which indicates that the solids were moving downwards on the average with respect to the riser wall. In transport regimes, the friction acts in the opposite direction. This behavior was quantified based on a sign of Fanning friction factor in the momentum balance equation. The time constant of the riser appears to be much higher in fast fluidized regime than in transport conditions.

  19. Attrition of limestone by impact loading in fluidized beds

    SciTech Connect

    Fabrizio Scala; Fabio Montagnaro; Piero Salatino

    2007-09-15

    The present study addresses limestone attrition and fragmentation associated with impact loading, a process which may occur extensively in various regions of fluidized bed (FB) combustors/gasifiers, primarily the jetting region of the bottom bed, the exit region of the riser, and the cyclone. An experimental protocol for the characterization of the propensity of limestone to undergo attrition/fragmentation by impact loading is reported. The application of the protocol is demonstrated with reference to an Italian limestone whose primary fragmentation and attrition by surface wear have already been characterized in previous studies. The experimental procedure is based on the characterization of the amount and particle size distribution of the debris generated upon the impact of samples of sorbent particles against a target. Experiments were carried out at a range of particle impact velocities between 10 and 45 m/s, consistent with jet velocities corresponding to typical pressure drops across FB gas distributors. The protocol has been applied to either raw or preprocessed limestone samples. In particular, the effect of calcination, sulfation, and calcination/recarbonation cycles on the impact damage suffered by sorbent particles has been assessed. The measurement of particle voidage and pore size distribution by mercury intrusion was also accomplished to correlate fragmentation with the structural properties of the sorbent samples. Fragmentation by impact loading of the limestone is significant. Lime displays the largest propensity to undergo impact damage, followed by the sorbent sulfated to exhaustion, the recarbonated sorbent, and the raw limestone. Fragmentation of the raw limestone and of the sulfated lime follows a pattern typical of the failure of brittle materials. The fragmentation behavior of lime and recarbonated lime better conforms to a disintegration failure mode, with an extensive generation of very fine fragments. 27 refs., 9 figs. 1 tab.

  20. Turndown studies for utility fluidized-bed boilers. Final report

    SciTech Connect

    Divilio, R.J.; Reed, R.R.

    1984-01-01

    This report contains a series of analyses that evaluate the turndown potential of the EPRI 6 x 6 test facility and the TVA 20 MW FBC pilot plant by variation of the fluidization velocity. The basis of the analyses is a heat balance program that incorporates basic principles of thermodynamics and fluidization. The heat balance program is used to explain the interrelationship of operating variables of a fluidized-bed boiler and to predict the steady state operating conditions of the boilers over a range of loads. Turndown analyses were performed on two tube bundle designs for the EPRI 6 x 6 test unit including a nine drawer tube bundle designed for 8 ft/sec operation and a twelve drawer bundle for operation up to 12 ft/sec. This twelve drawer bundle was found to have reasonable turndown characteristics between 4 and 12 ft/sec. At a 20 inch static bed depth, for example, this bundle should operate between 1545 and 1620/sup 0/F at 3.2% O/sub 2/ for loads from 4 to 12 ft/sec. In addition to the two bundles studies, a tube bundle capable of a 3:1 turndown range with a minimum temperature variation was designed for the 6 x 6 test facility. The tube bundle for the TVA 20 MW pilot plant was found to have excellent turndown characteristics between 4 and 8 ft/sec. For example, a 21 inch static bed should allow operation between 1541 and 1575/sup 0/F bed temperature at 3% O/sub 2/.

  1. Durability Testing of Fluidized Bed Steam Reforming Products

    SciTech Connect

    JANTZEN, CAROL M.; PAREIZS, JOHN M.; LORIER, TROY H.; MARRA, JAMES C.

    2005-07-01

    Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of radioactive wastes but especially aqueous high sodium wastes at the Hanford site, at the Idaho National Laboratory (INL), and at the Savannah River Site (SRS). The FBSR technology converts organic compounds to CO{sub 2} and H{sub 2}O, converts nitrate/nitrite species to N{sub 2}, and produces a solid residue through reactions with superheated steam, the fluidizing media. If clay is added during processing a ''mineralized'' granular waste form can be produced. The mineral components of the waste form are primarily Na-Al-Si (NAS) feldspathoid minerals with cage-like and ring structures and iron bearing spinel minerals. The cage and ring structured minerals atomically bond radionuclides like Tc{sup 99} and Cs{sup 137} and anions such as SO{sub 4}, I, F, and Cl. The spinel minerals appear to stabilize Resource Conservation and Recovery Act (RCRA) hazardous species such as Cr and Ni. Durability testing of the FBSR products was performed using ASTM C1285 (Product Consistency Test) and the Environmental Protection Agency (EPA) Toxic Characteristic Leaching Procedure (TCLP). The FBSR mineral products (bed and fines) evaluated in this study were found to be two orders of magnitude more durable than the Hanford Low Activity Waste (LAW) glass requirement of 2 g/m{sup 2} release of Na{sup +}. The PCT responses for the FBSR samples tested were consistent with results from previous FBSR Hanford LAW product testing. Differences in the response can be explained by the minerals formed and their effects on PCT leachate chemistry.

  2. Experimental study on coal multi-generation in dual fluidized beds

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoxu; Lu, Qinggang; Na, Yongjie; Liu, Qi

    2007-08-01

    An atmospheric test system of dual fluidized beds for coal multi-generation was built. One bubbling fluidized bed is for gasification and a circulating fluidized bed for combustion. The two beds are combined with two valves: one valve to send high temperature ash from combustion bed to the gasification bed and another valve to send char and ash from gasification bed to combustion bed. Experiments on Shenhua coal multi-generation were made at temperatures from 1112 K to 1191 K in the dual fluidized beds. The temperatures of the combustor are stable and the char combustion efficiency is about 98%. Increasing air/coal ratio to the fluidized bed leads to the increase of temperature and gasification efficiency. The maximum gasification efficiency is 36.7% and the calorific value of fuel gas is 10.7 MJ/Nm3. The tar yield in this work is 1.5%, much lower than that of pyrolysis. Carbon conversion efficiency to fuel gas and flue gas is about 90%.

  3. Countercurrent multistage fluidized bed reactor for immobilized biocatalysts: III. Hydrodynamic aspects.

    PubMed

    Vos, H J; van Houwelingen, C; Zomerdijk, M; Luyben, K C

    1990-08-01

    In Parts I and II of this series we described the modelling, design, and operation of a multistage fluidized bed reactor (MFBR) for immobilized biocatalysts. This article deals with those aspects of the MFBR which are different from single-stage fluidized beds which are operated in batch mode with respect to the solids. The semicontinuous transport of the particles requires perfect mixing of the particles in the reactor compartments, because particles are mainly transported from the bottom of these compartments. A large spread in the physical properties of the biocatalyst particles, especially of both size and density, may cause the particles to segregate into layers with different diameter and/or density. This affects the efficient use of the biocatalyst. The properties of the particles are dependent on the immobilization method. The suitability of different methods for possible future application in the MFBR is therefore compared. Because of segregation, successful use of a biofilm catalyst with a nonuniform thickness of the biofilm is doubtful. Experiments in a small scale reactor (+/- 0.1 m diameter) demonstrated that perfect particle mixing is possible using commercially available biocatalyst particles of uniform density. Co-immobilization of the biocatalyst with glass powder in a gel is a simple and effective method of increasing gel density. High density particles allow high liquid flow rates, and thus an improved external mass transfer can be achieved.The distributor plates, which separate the reactor compartments, must allow unhindered transport of particles. Therefore, the holes in these plates must have a diameter of at least 4.5 times that of the largest particles which are present in the particle mixture used. Furthermore, the plates must be designed such that, when scaling-up the reactor, a uniform liquid distribution over the cross-sectional area of the reactor occurs. Large-scale experiments were not carried out, but published correlations, indicate

  4. Flash Pyrolysis and Fractional Pyrolysis of Oleaginous Biomass in a Fluidized-bed Reactor

    NASA Astrophysics Data System (ADS)

    Urban, Brook

    Thermochemical conversion methods such as pyrolysis have the potential for converting diverse biomass feedstocks into liquid fuels. In particular, bio-oil yields can be maximized by implementing flash pyrolysis to facilitate rapid heat transfer to the solids along with short vapor residence times to minimize secondary degradation of bio-oils. This study first focused on the design and construction of a fluidized-bed flash pyrolysis reactor with a high-efficiency bio-oil recovery unit. Subsequently, the reactor was used to perform flash pyrolysis of soybean pellets to assess the thermochemical conversion of oleaginous biomass feedstocks. The fluidized bed reactor design included a novel feed input mechanism through suction created by flow of carrier gas through a venturi which prevented plugging problems that occur with a more conventional screw feeders. In addition, the uniquely designed batch pyrolysis unit comprised of two tubes of dissimilar diameters. The bottom section consisted of a 1" tube and was connected to a larger 3" tube placed vertically above. At the carrier gas flow rates used in these studies, the feed particles remained fluidized in the smaller diameter tube, but a reduction in carrier gas velocity in the larger diameter "disengagement chamber" prevented the escape of particles into the condensers. The outlet of the reactor was connected to two Allihn condensers followed by an innovative packed-bed dry ice condenser. Due to the high carrier gas flow rates in fluidized bed reactors, bio-oil vapors form dilute aerosols upon cooling which that are difficult to coalesce and recover by traditional heat exchange condensers. The dry ice condenser provided high surface area for inertial impaction of these aerosols and also allowed easy recovery of bio-oils after natural evaporation of the dry ice at the end of the experiments. Single step pyrolysis was performed between 250-610°C with a vapor residence time between 0.3-0.6s. At 550°C or higher, 70% of

  5. Anaerobic digestion of dairy wastewater by inverse fluidization: the inverse fluidized bed and the inverse turbulent bed reactors.

    PubMed

    Arnaiz, C; Buffiere, P; Elmaleh, S; Lebrato, J; Moletta, R

    2003-11-01

    This paper describes the application of the inverse fluidization technology to the anaerobic digestion of dairy wastewater. Two reactors were investigated: the inverse fluidized bed reactor and the inverse turbulent reactor. In these reactors, a granular floating solid is expanded by a down-flow current of effluent or an up-flow current of gas, respectively. The carrier particles (Extendospheres) were chosen for their large specific surface area (20,000 m2m(-3)) and their low energy requirements for fluidization (gas velocity of 1.5 mm s(-1), 5.4 m h(-1)). Organic load was increased stepwise by reducing hydraulic retention time from more than 60 days to 3 days, while maintaining constant the feed COD concentration. Both reactors achieved more than 90% of COD removal, at an organic loading rate of 10-12 kgCOD m(-3) d(-1), respectively. The performances observed were similar or even higher than that of other previously tested fluidized bed technologies treating the same wastewater. It was found that the main advantages of this system are: low energy requirement, because of the low fluidization velocities required; there is no need of a settling device, because solids accumulate at the bottom of the reactor, so they can be easily drawn out and particles with high-biomass content can be easily recovered. Lipid phosphate concentration has been revealed as a good method for biomass estimation in biofilms since it only includes living biomass.

  6. Self-assembly modified-mushroom nanocomposite for rapid removal of hexavalent chromium from aqueous solution with bubbling fluidized bed

    PubMed Central

    Xu, Fei; Liu, Xu; Chen, Yijiao; Zhang, Ke; Xu, Heng

    2016-01-01

    A self-assembled modified Pleurotus Cornucopiae material (SMPM) combined with improved Intermittent Bubbling Fluidized Bed (IBFB) was investigated to remove the hexavalent chromium ions in aqueous solution. After the modification, the powder-like raw material gradually self-assembled together to SMPM, which had crinkly porous structure, improved the Cr-accommodation ability in a sound manner. Optimized by Taguchi method, Cr(VI) removal efficiency was up to 75.91% and 48.01% for 100 mg/L and 500 mg/L initial concentration of Cr(VI), respectively. Results indicated that the metal removal was dependent on dosage of adsorbent, particle diameter and treatment time. The experimental data obtained from the biosorption process was successfully correlated with Freundlich isotherm model. Thermodynamic study indicated the endothermic nature of the process. The results confirmed that self-assembly modified Pleurotus Cornucopiae material could be applied for the removal of heavy metal from wastewater in continuous fluidized bed process. PMID:27188258

  7. Self-assembly modified-mushroom nanocomposite for rapid removal of hexavalent chromium from aqueous solution with bubbling fluidized bed

    NASA Astrophysics Data System (ADS)

    Xu, Fei; Liu, Xu; Chen, Yijiao; Zhang, Ke; Xu, Heng

    2016-05-01

    A self-assembled modified Pleurotus Cornucopiae material (SMPM) combined with improved Intermittent Bubbling Fluidized Bed (IBFB) was investigated to remove the hexavalent chromium ions in aqueous solution. After the modification, the powder-like raw material gradually self-assembled together to SMPM, which had crinkly porous structure, improved the Cr-accommodation ability in a sound manner. Optimized by Taguchi method, Cr(VI) removal efficiency was up to 75.91% and 48.01% for 100 mg/L and 500 mg/L initial concentration of Cr(VI), respectively. Results indicated that the metal removal was dependent on dosage of adsorbent, particle diameter and treatment time. The experimental data obtained from the biosorption process was successfully correlated with Freundlich isotherm model. Thermodynamic study indicated the endothermic nature of the process. The results confirmed that self-assembly modified Pleurotus Cornucopiae material could be applied for the removal of heavy metal from wastewater in continuous fluidized bed process.

  8. Bioregeneration of perchlorate-laden gel-type anion-exchange resin in a fluidized bed reactor.

    PubMed

    Venkatesan, Arjun K; Sharbatmaleki, Mohamadali; Batista, Jacimaria R

    2010-05-15

    Selective ion-exchange resins are very effective to remove perchlorate from contaminated waters. However, these resins are currently incinerated after one time use, making the ion-exchange process incomplete and unsustainable for perchlorate removal. Resin bioregeneration is a new concept that combines ion-exchange with biological reduction by directly contacting perchlorate-laden resins with a perchlorate-reducing bacterial culture. In this research, feasibility of the bioregeneration of perchlorate-laden gel-type anion-exchange resin was investigated. Bench-scale bioregeneration experiments, using a fluidized bed reactor and a bioreactor, were performed to evaluate the feasibility of the process and to gain insight into potential mechanisms that control the process. The results of the bioregeneration tests suggested that the initial phase of the bioregeneration process might be controlled by kinetics, while the later phase seems to be controlled by diffusion. Feasibility study showed that direct bioregeneration of gel-type resin was effective in a fluidized-bed reactor, and that the resin could be defouled, reused, and repeatedly regenerated using the method applied in this research.

  9. An investigation into the usefulness of different empirical modeling techniques for better control of spray-on fluidized bed melt granulation.

    PubMed

    Aleksić, Ivana; Đuriš, Jelena; Ibrić, Svetlana; Parojčić, Jelena

    2015-12-30

    Melt granulation in fluid bed processors is an emerging technique, but literature data regarding the modeling of this granulation method are lacking. In the present study different techniques (response surface analysis, multilayer perceptron neural network, and partial least squares method) were applied for modeling of spray-on fluidized bed melt granulation. Experiments were organized in line with central composite design. The effect of binder content and spray air pressure on granule properties was evaluated. The results obtained indicate that binder content can be identified as a critical factor controlling the granule size and size distribution. It was found that agglomeration mechanism involved, i.e., granule shape, can be greatly influenced by binder properties. The spray air pressure was identified as critical process parameter affecting granule flowability. The results presented indicate that application of in silico tools enables enhanced understanding and better control of novel pharmaceutical processes, such as melt granulation in fluidized bed. The artificial neural networks and partial least squares method were found to be superior to response surface methodology in prediction of granule properties. According to the results obtained, application of more advanced empirical modeling techniques complementary to design of experiments can be a suitable approach in defining the design space and optimization of spray-on fluidized bed melt granulation. PMID:26551673

  10. Four stage, fluidized bed gasification process minimizes NO{sub x}

    SciTech Connect

    Lewis, F.M.; Haug, R.T.

    1999-07-01

    In 1981, after a long and thorough study of alternative methods of sewage sludge (biosolids) disposal, the City of Los Angeles (CLA) embarked on a pilot test program to incinerate dried sewage sludge from its Hyperion Wastewater Treatment Plant. This dried sludge is typically 47% ash, 53% combustible, and has an average higher heating value (HHV), moisture, ash-free (MAF) of 10,675 Btu/Lbm. The dried sludge is called sludge derived fuel (SDF). Approximately 8% of the MAF fraction of SDF is fuel-bound nitrogen. When SDF, with its extremely high fuel-bound nitrogen, was combusted in conventional multiple hearth and fluidized bed pilot plant furnaces, NO{sub x} emissions were extremely high ({gt}1,000 ppm). Faced with this dilemma, the CLA initiated an R and D program to reduce NO{sub x}. The pilot tests with a sub-stoichiometric fluid bed and an excess air afterburner (two-stages) reduced NO{sub x} to 400--600 ppm. With one intermediate stage added (three-stage), NO{sub x} was reduced to 130--150 ppm. However, when the following four-stage process was developed and tested, NO{sub x} was reduced to 50--75 ppm. Stage 1: Sub-stoichiometric fluidized bed operating at a nominal 30% stoichiometric air (SA). Stage 2:Sub-stoichiometric zone operating at a nominal 80% SA. Stage 3: Stoichiometric zone operating at a nominal 100% SA. Stage 4: Excess air zone (Afterburner) operating at a nominal 135% SA (35% excess air). After pilot testing was complete and design parameters established, three full-size, fluid bed gasifiers (two operational--one standby) were designed, constructed and operated until 1996. This paper describes the design, operation, and emission testing of these four-stage fluid bed gasifiers with special emphasis on the problems of (a) pneumatic feeding of SDF powder into the pressurized bed and (b) baghouse fabrics (expanded PTEE membrane on PTFE scrim). Final emission test results for NO{sub x} and other criteria pollutants are also presented.

  11. Evaluation of wall boundary condition parameters for gas-solids fluidized bed simulations

    SciTech Connect

    Li, Tingwen; Benyahia, Sofiane

    2013-10-01

    Wall boundary conditions for the solids phase have significant effects on numerical predictions of various gas-solids fluidized beds. Several models for the granular flow wall boundary condition are available in the open literature for numerical modeling of gas-solids flow. In this study, a model for specularity coefficient used in Johnson and Jackson boundary conditions by Li and Benyahia (AIChE Journal, 2012, 58, 2058-2068) is implemented in the open-source CFD code-MFIX. The variable specularity coefficient model provides a physical way to calculate the specularity coefficient needed by the partial-slip boundary conditions for the solids phase. Through a series of 2-D numerical simulations of bubbling fluidized bed and circulating fluidized bed riser, the model predicts qualitatively consistent trends to the previous studies. Furthermore, a quantitative comparison is conducted between numerical results of variable and constant specularity coefficients to investigate the effect of spatial and temporal variations in specularity coefficient.

  12. Design and evaluation of fluidized bed heat recovery for diesel engine systems

    NASA Technical Reports Server (NTRS)

    Hamm, J. R.; Newby, R. A.; Vidt, E. J.; Lippert, T. E.

    1985-01-01

    The potential of utilizing fluidized bed heat exchangers in place of conventional counter-flow heat exchangers for heat recovery from adiabatic diesel engine exhaust gas streams was studied. Fluidized bed heat recovery systems were evaluated in three different heavy duty transport applications: (1) heavy duty diesel truck; (2) diesel locomotives; and (3) diesel marine pushboat. The three applications are characterized by differences in overall power output and annual utilization. For each application, the exhaust gas source is a turbocharged-adiabatic diesel core. Representative subposed exhaust gas heat utilization power cycles were selected for conceptual design efforts including design layouts and performance estimates for the fluidized bed heat recovery heat exchangers. The selected power cycles were: organic rankine with RC-1 working fluid, turbocompound power turbine with steam injection, and stirling engine. Fuel economy improvement predictions are used in conjunction with capital cost estimates and fuel price data to determine payback times for the various cases.

  13. Volatiles combustion in fluidized beds. [Quarterly] technical progress report, 4 March 1994--3 June 1994

    SciTech Connect

    Pendergrass, R.A. II; Hesketh, R.P.

    1994-08-01

    The goal of this project is to investigate the conditions in which volatiles will bum within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization will be performed to characterize the effect of particle surface area, initial fuel concentration, and particle type on the, inhibition of volatiles within a fluidized bed. The work conducted during the period 4 March, 1994 through 3 June, 1994 is reported in this technical progress report. The experimental work during this time period consists primarily of data collection. Gas composition results using two sand particle diameters of 0.531 and 0.126 mm. Three graphs at equivalence ratios of 0.5, 1.0 and 2.0 for propane in air are reported for the 0.531 mm sand size. For the 0.126 nun sand size stoichiometric propane and air are results are reported.

  14. Study of instrumentation needs for process control and safety in coal fluidized-bed combustion systems

    SciTech Connect

    Herzenberg, C.L.; Griggs, K.E.; Henry, R.F.; Podolski, W.F.

    1981-02-01

    A study was conducted to evaluate the current state of the art of instrumentation for planned and operating fluidized-bed combustion systems. This study is intended to identify instrumentation needs and serve as a data base for projects to develop this instrumentation. A considerable number of needs for measurements for which presently available instrumentation is not suitable were reported by respondents. The identified deficiencies are presented with the associated physical parameter ranges for FBC processes. New techniques and instrumentation under development, as well as some available alternative instruments, are discussed briefly. Also, newly instituted mechanisms for technical information exchange on instrumentation for fossil energy applications are identified. Development of instruments to meet the identified measurement deficiencies is recommended in order to ensure the feasibility of automatic control of large-scale fluidized-bed combustion systems, and to advance the state of the art of fluidized-bed combustion technology.

  15. Cultivation of microorganisms in an air-solid fluidized bed fermentor with agitators

    SciTech Connect

    Tanaka, M.; Kawaide, A.; Matsuno, R.

    1986-09-01

    The productivity of a cell mass of Saccharomyces cerevisiae and enzymes of Eupenicillium javanicum increased by cultivation in an air-solid fluidized bed fermentor with agitators. The usefulness of the apparatus for the fluidized bed culture was verified. The productivity of amylase and protease of the fungus by fluidized bed culture was twice as high as that by stationary culture, considering the dry weight of cells and the enzyme activity. Physiological properties of yeast cells were changed by the fludized bed culture; there was a decrease in the cell size of yeast and changes to the aerobic properties of the yeast cells resulting from excessive supply of oxygen with a high flowrate of air. 8 references.

  16. Minimum liquid fluidization velocity in gas-liquid-solid fluidized beds

    SciTech Connect

    Briens, L.A.; Briens, C.L.; Margaritis, A.; Hay, J.

    1997-05-01

    Accurate detection of minimum liquid fluidization is essential to the successful operation of gas-liquid-solid fluidized beds, especially when particle or liquid properties evolve. A gas-liquid-solid system of 3-mm glass beads exhibits three distinct flow regimes as the liquid velocity is increased: compacted, agitated and fluidized-bed regimes. Measurements showed that the bed is not fluidized in the agitated bed regime. Pressure gradient and bed height measurements do not provide the minimum liquid fluidization velocity; instead, they offer the velocity between the compacted and agitated bed regimes. Time-averaged signals are not reliable for determining the minimum liquid fluidization velocity. It can be obtained from the standard deviation, the average frequency, the Hurst exponent and the V statistic of the cross-sectional average conductivity, which can be measured under many industrial conditions. Examples of applications of gas-liquid-solid fluidized bed reactors include coal liquefaction and petroleum hydrotreating.

  17. Operation of magnetically assisted fluidized beds in microgravity and variable gravity: experiment and theory

    NASA Astrophysics Data System (ADS)

    Sornchamni, T.; Jovanovic, G. N.; Reed, B. P.; Atwater, J. E.; Akse, J. R.; Wheeler, R. R.

    2004-01-01

    The conversion of solid waste into useful resources in support of long duration manned missions in space presents serious technological challenges. Several technologies, including supercritical water oxidation, microwave powered combustion and fluidized bed incineration, have been tested for the conversion of solid waste. However, none of these technologies are compatible with microgravity or hypogravity operating conditions. In this paper, we present the gradient magnetically assisted fluidized bed (G-MAFB) as a promising operating platform for fluidized bed operations in the space environment. Our experimental and theoretical work has resulted in both the development of a theoretical model based on fundamental principles for the design of the G-MAFB, and also the practical implementation of the G-MAFB in the filtration and destruction of solid biomass waste particles from liquid streams.

  18. Operation of magnetically assisted fluidized beds in microgravity and variable gravity: experiment and theory.

    PubMed

    Sornchamni, T; Jovanovic, G N; Reed, B P; Atwater, J E; Akse, J R; Wheeler, R R

    2004-01-01

    The conversion of solid waste into useful resources in support of long duration manned missions in space presents serious technological challenges. Several technologies, including supercritical water oxidation, microwave powered combustion and fluidized bed incineration, have been tested for the conversion of solid waste. However, none of these technologies are compatible with microgravity or hypogravity operating conditions. In this paper, we present the gradient magnetically assisted fluidized bed (G-MAFB) as a promising operating platform for fluidized bed operations in the space environment. Our experimental and theoretical work has resulted in both the development of a theoretical model based on fundamental principles for the design of the G-MAFB, and also the practical implementation of the G-MAFB in the filtration and destruction of solid biomass waste particles from liquid streams. PMID:15846878

  19. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Andy Wu; John T. Riley

    2004-10-30

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period July 1, 2004 through September 30, 2004. The following tasks have been completed. First, renovation of the new Combustion Laboratory and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building have started. Second, the design if the component parts of the CFBC system have been reviewed and finalized so that the drawings may be released to the manufacturers during the next quarter. Third, the experiments for solid waste (chicken litter) incineration have been conducted using a Thermogravimetric Analyzer (TGA). This is in preparation for testing in the simulated fluidized-bed combustor. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter has been outlined in this report.

  20. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Andy Wu; John T. Riley

    2005-01-30

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period October 1, 2004 through December 31, 2004. The following tasks have been completed. First, the renovation of the new Combustion Laboratory and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building have proceeded well. Second, the detailed design of supporting and hanging structures for the CFBC was completed. Third, the laboratory-scale simulated fluidized-bed facility was modified after completing a series of pretests. The two problems identified during the pretest were solved. Fourth, the carbonization of chicken waste and coal was investigated in a tube furnace and a Thermogravimetric Analyzer (TGA). The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter has been outlined in this report.

  1. Atmospheric fluidized bed combustion (AFBC) plants: an operations and maintenance study

    SciTech Connect

    Jack A. Fuller; Harvie Beavers; Robert Bessette

    2006-06-15

    The authors analyzed data from a fluidized bed boiler survey distributed during the spring of 2003 to develop appropriate AFBC (Atmospheric Fluidized Bed Combustion) performance benchmarks. The survey was sent to members of CIBO (Council of Industrial Boiler Owners), who sponsored the survey, as well as to other firms who had an operating AFBC boiler on-site. There were three primary purposes for the collection and analysis of the data contained in this fluidized bed boiler survey: (1) To develop AFBC benchmarks on technical, cost, revenue, and environmental issues; (2) to inform AFBC owners and operators of contemporary concerns and issues in the industry; (3) to improve decision making in the industry with respect to current and future plant start-ups and ongoing operations.

  2. [Radiation transformation mechanism in a photocatalytic reactor of three-phase internal circulating fluidized bed].

    PubMed

    You, Hong; Luo, Wei-nan; Yao, Jie; Chen, Ping; Cai, Wei-min

    2005-01-01

    A novel three-phase internal circulating fluidized bed photocatalytic reactor was established and the radiation transformation in which was investigated. The experimental results indicate that with the interaction of gas and solid (gas flux > 0.3m3/h), the radiation transformation in the reactor along radial direction conforms to a definite exponential function, which agrees to formula Rose about the rules of light intensity distribution through evenly suspended particles. The value of radiation energy is affected by the initial light intensity, the concentration of photocatalyst and the thickness of liquid layer. The aerated gas amount only influence the state of the fluidized bed and has little effect on the distribution of light intensity along radical direction. Photocatalytic degradation of Rhodamine B indicate that the efficiency of three-phase internal circulating fluidized bed is much higher than slurry bed. The optimal catalyst concentration of this system is 10 - 12g/L.

  3. Operation of magnetically assisted fluidized beds in microgravity and variable gravity: experiment and theory

    NASA Technical Reports Server (NTRS)

    Sornchamni, T.; Jovanovic, G. N.; Reed, B. P.; Atwater, J. E.; Akse, J. R.; Wheeler, R. R.

    2004-01-01

    The conversion of solid waste into useful resources in support of long duration manned missions in space presents serious technological challenges. Several technologies, including supercritical water oxidation, microwave powered combustion and fluidized bed incineration, have been tested for the conversion of solid waste. However, none of these technologies are compatible with microgravity or hypogravity operating conditions. In this paper, we present the gradient magnetically assisted fluidized bed (G-MAFB) as a promising operating platform for fluidized bed operations in the space environment. Our experimental and theoretical work has resulted in both the development of a theoretical model based on fundamental principles for the design of the G-MAFB, and also the practical implementation of the G-MAFB in the filtration and destruction of solid biomass waste particles from liquid streams. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  4. Development of algorithms for capacitance imaging techniques for fluidized bed flow fields. 1990 Annual report

    SciTech Connect

    Loudin, W.J.

    1991-01-01

    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.

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

    SciTech Connect

    Loudin, W.J.

    1991-01-01

    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.

  6. DEVELOPMENT OF PRESSURIZED CIRCULATING FLUIDIZED BED PARTIAL GASIFICATION MODULE (PGM)

    SciTech Connect

    Unknown

    2002-03-29

    Foster Wheeler Development Corporation is working under DOE contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% while producing near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The unique aspect of the process is that it utilizes a pressurized circulating fluidized bed partial gasifier and does not attempt to consume the coal in a single step. To convert all the coal to syngas in a single step requires extremely high temperatures ({approx}2500 to 2800 F) that melt and vaporize the coal and essentially drive all coal ash contaminants into the syngas. Since these contaminants can be corrosive to power generating equipment, the syngas must be cooled to near room temperature to enable a series of chemical processes to clean the syngas. Foster Wheeler's process operates at much lower temperatures that control/minimize the release of contaminants; this eliminates/minimizes the need for the expensive, complicated syngas heat exchangers and chemical cleanup systems typical of high temperature gasification. By performing the gasification in a circulating bed, a significant amount of syngas can still be produced despite the reduced temperature and the circulating bed allows easy scale up to large size plants. Rather than air, it can also operate with oxygen to facilitate

  7. Characterization of biofilm in 200W fluidized bed reactors

    SciTech Connect

    Lee, Michelle H.; Saurey, Sabrina D.; Lee, Brady D.; Parker, Kent E.; Eisenhauer, Emalee E. R.; Cordova, Elsa A.; Golovich, Elizabeth C.

    2014-09-29

    Contaminated groundwater beneath the 200 West Area at the Hanford Site in Southeast Washington is currently being treated using a pump and treat system to remove organics, inorganics, radionuclides, and metals. A granular activated carbon-based fluidized bed reactor (FBR) has been added to remove nitrate, hexavalent chromium and carbon tetrachloride. Initial analytical results indicated the microorganisms effectively reduced many of the contaminants to less than cleanup levels. However shortly thereafter operational upsets of the FBR include carbon carry over, over production of microbial extracellular polymeric substance (biofilm) materials, and over production of hydrogen sulfide. As a result detailed investigations were undertaken to understand the functional diversity and activity of the microbial community present in the FBR over time. Molecular analyses including terminal restriction fragment length polymorphism analysis, quantitative polymerase chain reaction and fluorescent in situ hybridization analyses were performed on the microbial community extracted from the biofilm within the bed and from the inoculum, to determine functional dynamics of the FBR bed over time and following operational changes. Findings from these analyses indicated: 1) the microbial community within the bed was completely different than community used for inoculation, and was likely from the groundwater; 2) analyses early in the testing showed an FBR community dominated by a few Curvibacter and Flavobacterium species; 3) the final sample taken indicated that the microbial community in the FBR bed had become more diverse; and 4) qPCR analyses indicated that bacteria involved in nitrogen cycling, including denitrifiers and anaerobic ammonia oxidizing bacteria, were dominant in the bed. These results indicate that molecular tools can be powerful for determining functional diversity within FBR type reactors. Coupled with micronutrient, influent and effluent chemistry

  8. Sampling and instrumentation for fluidized-bed combustion. Annual report, October 1978-September 1979

    SciTech Connect

    Johnson, I.; Podolski, W.F.; Myles, K.M.

    1980-09-01

    In the first section of this report, background information is presented on instrumentation for fluidized-bed combustion, i.e., for process control, scientific investigation, and safety in planned and operating fluidized-bed combustion systems. The objective of this study is to update and extend the fluidized-bed portion of a preceding report, A Study of the State-of-the-Art of Instrumentation for Process Control and Safety in Large-Scale Coal Gasification, Liquefaction, and Fluidized-Bed Combustion Systems, ANL-76-4. The second section of this report describes two prototype mass flow rate instruments installed on the solids feed lines of an existing ANL fluidized-bed combustor. The Fossil Instrumentation Group at ANL designed, fabricated, and installed these instruments in cooperation with Chemical Engineering Division personnel - one on the coal feedline and one on the coal/limestone feedline. Each instrument consisted of a capacitive sensor spoolpiece and an associated preamplifier and signal conditioning. One channel of each instrument provides three outputs. One delivers a density signal while two others deliver two signals for measuring velocity by cross-correlation. Operation was verified by using laboratory signal analyzers to process the signals. The third section of this report summarizes the results of a Spectron Development Laboratory subcontract from ANL to investigate analytical techniques suitable for monitoring the concentration of gaseous alkali compounds in the hot gas stream from a fluidized-bed combustor. It was concluded from the study that the concept of using the Na/sub 2/SO/sub 4/ dew point to detect the onset of hot corrosion conditions is the most attractive of the techniques evaluated.

  9. Scaled-bed modeling for fluidized-bed combustors. Semi-annual report, October 1, 1980-March 31, 1981

    SciTech Connect

    Fitzgerald, T.J.; Crane, S.D.

    1981-03-01

    Progress is reported in developing scaled models of coal-fired fluidized-bed combustors which can be used with confidence to obtain performance data for predicting the performance of full scale units. Construction of two 1/4 scale atmospheric pressure fluidized bed combustors is nearing completion. (LCL)

  10. A semi-empirical model for pressurised air-blown fluidized-bed gasification of biomass.

    PubMed

    Hannula, Ilkka; Kurkela, Esa

    2010-06-01

    A process model for pressurised fluidized-bed gasification of biomass was developed using Aspen Plus simulation software. Eight main blocks were used to model the fluidized-bed gasifier, complemented with FORTRAN subroutines nested in the programme to simulate hydrocarbon and NH(3) formation as well as carbon conversion. The model was validated with experimental data derived from a PDU-scale test rig operated with various types of biomass. The model was shown to be suitable for simulating the gasification of pine sawdust, pine and eucalyptus chips as well as forest residues, but not for pine bark or wheat straw.

  11. Production of activated carbon from coconut shell char in a fluidized bed reactor

    SciTech Connect

    Sai, P.M.S.; Ahmed, J.; Krishnaiah, K.

    1997-09-01

    Activated carbon is produced from coconut shell char using steam or carbon dioxide as the reacting gas in a 100 mm diameter fluidized bed reactor. The effect of process parameters such as reaction time, fluidizing velocity, particle size, static bed height, temperature of activation, fluidizing medium, and solid raw material on activation is studied. The product is characterized by determination of iodine number and BET surface area. The product obtained in the fluidized bed reactor is much superior in quality to the activated carbons produced by conventional processes. Based on the experimental observations, the optimum values of process parameters are identified.

  12. Semisolid state fermentation of baker's yeast in an air-fluidized bed fermentor.

    PubMed

    Hong, K; Tanner, R D; Crooke, P S; Malaney, G W

    1988-08-01

    In an attempt to grow microorganisms other than fungi using a solid-state fermentation process, a model system of Baker's yeast (Saccharomyces cerevisiae) was cultured in an air-fluidized bed fermentor. A semisolid potato mixture (pretreated with alpha-amylase) was used for the substrate in this highly aerated system. The growth of Baker's yeast in this air-fluidized bed process was easily controllable and very reproducible. Once feasible moisture levels and air flow rates were determined, the independent variables studied were the amount of the enzyme used for digesting the potato starch, the size of the yeast inoculum, and the concentration of the added defined medium.

  13. Fluidized-bed catalytic coal-gasification process. [US patent; pretreatment to minimize agglomeration

    DOEpatents

    Euker, C.A. Jr.; Wesselhoft, R.D.; Dunkleman, J.J.; Aquino, D.C.; Gouker, T.R.

    1981-09-14

    Coal or similar carbonaceous solids impregnated with gasification catalyst constituents are oxidized by contact with a gas containing between 2 vol % and 21 vol % oxygen at a temperature between 50 and 250/sup 0/C in an oxidation zone and the resultant oxidized, catalyst impregnated solids are then gasified in a fluidized bed gasification zone at an elevated pressure. The oxidation of the catalyst impregnated solids under these conditions insures that the bed density in the fluidized bed gasification zone will be relatively high even though the solids are gasified at elevated pressure and temperature.

  14. Exploratory and basic fluidized-bed combustion studies. Quarterly report, January-March 1980

    SciTech Connect

    Johnson, I.; Myles, K.M.; Swift, W.M.

    1980-12-01

    This work supports development studies for both atmospheric and pressurized fluidized-bed coal combustion. Laboratory and process development studies are aimed at providing needed information on limestone utilization, removal of particulates and alkali metal compounds from the flue gas, control of SO/sub 2/ and trace pollutants emissions, and other aspects of fluidized-bed combustion. This report presents information on: (1) the development of a limestone utilization predictive methodology, (2) studies of particle breakup and elutriation, (3) basic studies on limestone sulfation enhancement by hydration, (4) studies of the kinetics of the hydration process, and (5) an investigation of various hydration process concepts.

  15. Refractory experience in circulating fluidized bed combustors, Task 7. Final report

    SciTech Connect

    Vincent, R.Q.

    1989-11-01

    This report describes the results of an investigation into the status of the design and selection of refractory materials for coal-fueled circulating fluidized-bed combustors. The survey concentrated on operating units in the United States manufactured by six different boiler vendors: Babcock and Wilcox, Combustion Engineering, Foster Wheeler, Keeler Dorr-Oliver, Pyropower, and Riley Stoker. Information was obtained from the boiler vendors, refractory suppliers and installers, and the owners/operators of over forty units. This work is in support of DOE`s Clean Coal Technology program, which includes circulating fluidized-bed technology as one of the selected concepts being evaluated.

  16. Model-free adaptive control of supercritical circulating fluidized-bed boilers

    DOEpatents

    Cheng, George Shu-Xing; Mulkey, Steven L

    2014-12-16

    A novel 3-Input-3-Output (3.times.3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7.times.7) MFA control system is also described for controlling a combined 3-Input-3-Output (3.times.3) process of Boiler-Turbine-Generator (BTG) units and a 5.times.5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

  17. Fluidized Bed Selective Oxidation-Sulfation Roasting of Nickel Sulfide Concentrate: Part I. Oxidation Roasting

    NASA Astrophysics Data System (ADS)

    Yu, Dawei; Utigard, Torstein A.; Barati, Mansoor

    2014-04-01

    Two-stage oxidation-sulfation roasting of nickel sulfide concentrate in fluidized bed was investigated to generate water-soluble metal sulfates as an alternative process to smelting of the sulfide concentrate for the recovery of valuable metals. The first stage, i.e., oxidation roasting, was employed to preferentially oxidize the iron before performing sulfation roasting. A batch fluidized bed roaster was constructed for roasting tests. Roasting products from various roasting temperatures and different roasting times were analyzed by SEM/EDS, EPMA, XRD, and ICP-OES to investigate the oxidation roasting behavior of the nickel concentrate as a function of temperature and time.

  18. Fine-grid simulations of gas-solids flow in a circulating fluidized bed

    SciTech Connect

    Benyahia, S.

    2012-01-01

    This research note demonstrates that more accurate predictions of a two-fluid model for the riser section of a circulating fluidized bed are obtained as the grid size is equally refined along all the directions of the gas-particle flow. However, two-fluid simulations of large-scale fluidized beds with such a fine mesh are currently computationally prohibitive. Alternatively,subgrid models can significantly reduce the simulation time of multiphase flow by using coarse mesh, whereas maintaining a high level of accuracy.

  19. Synthesis of a nanosilica supported CO2 sorbent in a fluidized bed reactor

    NASA Astrophysics Data System (ADS)

    Soria-Hoyo, C.; Valverde, J. M.; van Ommen, J. R.; Sánchez-Jiménez, P. E.; Pérez-Maqueda, L. A.; Sayagués, M. J.

    2015-02-01

    CaO has been deposited on a nanosilica powder matrix by a procedure based on atomic layer deposition (ALD) in a fluidized bed reactor at atmospheric pressure following a potentially scalable process. In previous works ALD in gas fluidized bed has been mostly performed under reduced pressure, which hampers scaling-up the production technology. The material synthesized in the present work is tested as CO2 solid sorbent at calcium looping conditions. Multicyclic thermogravimetric analysis (TGA) shows that the nanosilica support stabilizes the capture capacity of CaO. EDX-STEM analysis illustrates the presence of Ca well distributed on the surface of the SiO2 nanoparticles.

  20. Prediction of product distribution in fine biomass pyrolysis in fluidized beds based on proximate analysis.

    PubMed

    Kim, Sung Won

    2015-01-01

    A predictive model was satisfactorily developed to describe the general trends of product distribution in fluidized beds of lignocellulosic biomass pyrolysis. The model was made of mass balance based on proximate analysis and an empirical relationship with operating parameters including fluidization hydrodynamics. The empirical relationships between product yields and fluidization conditions in fluidized bed pyrolyzers were derived from the data of this study and literature. The gas and char yields showed strong functions of temperature and vapor residence time in the pyrolyzer. The yields showed a good correlation with fluidization variables related with hydrodynamics and bed mixing. The predicted product yields based on the model well accorded well with the experimental data.

  1. Two-stage fluidized-bed/cyclonic agglomerating incinerator. Technology spotlight report

    SciTech Connect

    1995-08-01

    The two-stage fluidized-bed/cyclonic agglomerating incinerator combines and improves upon the fluidized-bed, agglomeration/ incineration-technology and the cyclonic-combustion technology developed at Institute of Gas Technolgy (IGT) over many years. The result is a unique and extremely flexible incinerator for solid, liquid, and gaseous wastes. The system can operate over a wide range of conditions and has a destruction and removal efficiency (DRE) greater than 99.99%. Solid inorganic contaminants are contained within aglassy matrix, rendering them benign and suitable for disposal in an ordinary landfill.

  2. In-line monitoring of granule moisture in fluidized-bed dryers using microwave resonance technology.

    PubMed

    Buschmüller, Caroline; Wiedey, Wolfgang; Döscher, Claas; Dressler, Jochen; Breitkreutz, Jörg

    2008-05-01

    This is the first report on in-line moisture measurement of pharmaceutical products by microwave resonance technology. In order to meet the FDA's PAT approach, a microwave resonance sensor appropriate for pharmaceutical use was developed and implemented into two different fluidized-bed dryers. The novel sensor enables a continuous moisture measurement independent from the product density. Hence, for the first time precise real time determination of the moisture in pharmaceutical granules becomes possible. The qualification of the newly developed sensor was performed by drying placebo granules under experimental conditions and the validation using drug loaded granules under real process conditions. The results of the investigations show good correlations between water content of the granules determined by the microwave resonance sensor and both reference methods, loss on drying by infrared light exposure and Karl Fischer titration. Furthermore, a considerable time saving in the drying process was achieved through monitoring the residual water content continuously by microwave resonance technology instead of the formerly used discontinuous methods. PMID:17976965

  3. Fundamental study on transient bubble (slug) behavior by characterizing transient forces of solid particles in fluidized beds

    SciTech Connect

    Kono, H.O.

    1991-01-01

    The objective of this work is to recognize and interpret the signals of transient motion of bubbles (slugs) in fluidized beds by measuring and utilizing the signals of transient motion of solid particles. The two signals were measured simultaneously and also synchronized by using the TTL signal technique in the same fluidized beds. Also, a simultaneous study of video bubble image, transient force and pressure signals was initiated in a two dimensional fluidized bed. we successfully synchronized three signals so that the relationship of bubble behavior and force pressure signals can be identified and characterized. It has been found that bubble image can well be correlated to the transient force signal of solid particles under certain conditions in three dimensional fluidized beds. Accordingly, it seems that the transient force signals can significantly help understanding the transient motion of bubbles (slugs), which is important to design the fluidized beds.

  4. Fundamental study on transient bubble (slug) behavior by characterizing transient forces of solid particles in fluidized beds. 1990 Annual report

    SciTech Connect

    Kono, H.O.

    1991-01-01

    The objective of this work is to recognize and interpret the signals of transient motion of bubbles (slugs) in fluidized beds by measuring and utilizing the signals of transient motion of solid particles. The two signals were measured simultaneously and also synchronized by using the TTL signal technique in the same fluidized beds. Also, a simultaneous study of video bubble image, transient force and pressure signals was initiated in a two dimensional fluidized bed. we successfully synchronized three signals so that the relationship of bubble behavior and force pressure signals can be identified and characterized. It has been found that bubble image can well be correlated to the transient force signal of solid particles under certain conditions in three dimensional fluidized beds. Accordingly, it seems that the transient force signals can significantly help understanding the transient motion of bubbles (slugs), which is important to design the fluidized beds.

  5. Verification of the Accountability Method as a Means to Classify Radioactive Wastes Processed Using THOR Fluidized Bed Steam Reforming at the Studsvik Processing Facility in Erwin, Tennessee, USA - 13087

    SciTech Connect

    Olander, Jonathan; Myers, Corey

    2013-07-01

    Studsviks' Processing Facility Erwin (SPFE) has been treating Low-Level Radioactive Waste using its patented THOR process for over 13 years. Studsvik has been mixing and processing wastes of the same waste classification but different chemical and isotopic characteristics for the full extent of this period as a general matter of operations. Studsvik utilizes the accountability method to track the movement of radionuclides from acceptance of waste, through processing, and finally in the classification of waste for disposal. Recently the NRC has proposed to revise the 1995 Branch Technical Position on Concentration Averaging and Encapsulation (1995 BTP on CA) with additional clarification (draft BTP on CA). The draft BTP on CA has paved the way for large scale blending of higher activity and lower activity waste to produce a single waste for the purpose of classification. With the onset of blending in the waste treatment industry, there is concern from the public and state regulators as to the robustness of the accountability method and the ability of processors to prevent the inclusion of hot spots in waste. To address these concerns and verify the accountability method as applied by the SPFE, as well as the SPFE's ability to control waste package classification, testing of actual waste packages was performed. Testing consisted of a comprehensive dose rate survey of a container of processed waste. Separately, the waste package was modeled chemically and radiologically. Comparing the observed and theoretical data demonstrated that actual dose rates were lower than, but consistent with, modeled dose rates. Moreover, the distribution of radioactivity confirms that the SPFE can produce a radiologically homogeneous waste form. The results of the study demonstrate: 1) the accountability method as applied by the SPFE is valid and produces expected results; 2) the SPFE can produce a radiologically homogeneous waste; and 3) the SPFE can effectively control the waste package

  6. Comparion of Mercury Emissions Between Circulating Fluidized Bed Boiler and Pulverized Coal Boiler

    NASA Astrophysics Data System (ADS)

    Wang, Y. J.; Duan, Y. F.; Zhao, C. S.

    Mercury emissions between a circulating fluidized bed (CFB) utility boiler and two pulverized coal (PC) boilers equipped with electrostatic precipitators (ESP) were in situ measured and compared. The standard Ontario Hydro Method (OHM) was used to sample the flue gas before and after the ESP. Various mercury speciations such as Hg0, Hg2+ and Hgp in flue gas and total mercury in fly ashes were analyzed. The results showed that the mercury removal rate of the CFB boiler is nearly 100%; the mercury emission in stack is only 0.028 g/h. However, the mercury removal rates of the two PC boilers are 27.56% and 33.59% respectively, the mercury emissions in stack are 0.80 and 51.78 g/h respectively. It concluded that components of the ESP fly ashes especially their unburnt carbons have remarkable influence on mercury capture. Pore configurations of fine fly ash particles have non-ignored impacts on mercury emissions.

  7. Effect of pressure on second-generation pressurized fluidized bed combustion plants

    NASA Astrophysics Data System (ADS)

    Robertson, A.; Bonk, D.

    1994-04-01

    In the search for a more efficient, less costly, and more environmentally responsible method for generating electrical power from coal, research and development has turned to advanced pressurized fluidized bed combustion (PFBC) and coal gasification technologies. A logical extension of this work is the second-generation PFBC plant, which incorporates key components of each of these technologies. In this new type of plant, coal is devolatilized/carbonized before it is injected into the PFB combustor bed, and the low-Btu fuel gas produced by this process is burned in a gas turbine topping combustor. By integrating coal carbonization with PFB coal/char combustion, gas turbine inlet temperatures higher than 1149 deg C (2100 deg F) can be achieved. The carbonizer, PFB combustor, and particulate-capturing hot gas cleanup systems operate at 871 deg C (1600 deg F), permitting sulfur capture by lime-based sorbents and minimizing the release of coal contaminants to the gases. This paper presents the performance and economics of this new type of plant and provides a brief overview of the pilot plant test programs being conducted to support its development.

  8. Performance of the Fluidized Bed Steam Reforming Product Under Hydraulically Unsaturated Conditions

    SciTech Connect

    Neeway, James J.; Qafoku, Nikolla; Williams, Benjamin D.; Rod, Kenton A.; Bowden, Mark E.; Brown, Christopher F.; Pierce, Eric M.

    2014-05-01

    Currently, several candidates for secondary waste immobilization at the Hanford site in the State of Washington, USA are being considered. To demonstrate the durability of the product in the unsaturated Integrated Disposal Facility (IDF) at the site, a series of tests have been performed one of the candidate materials using the Pressurized Unsaturated Flow (PUF) system. The material that was tested was the Fluidized Bed Steam Reformer (FBSR) granular product and the granular product encapsulated in a geopolymer matrix. The FBSR product is composed primarily of an insoluble sodium aluminosilicate matrix with the dominant phases being feldspathoid minerals mostly nepheline, sodalite, and nosean. The PUF test method allows for the accelerated weathering of materials, including radioactive waste forms, under hydraulically unsaturated conditions, thus mimicking the open-flow and transport properties that most likely will be present at the IDF. The experiments show a trend of decreasing tracer release as a function of time for several of the elements released from the material including Na, Si, Al, and Cs. However, some of the elements, notably I and Re, show a steady release throughout the yearlong test. This result suggests that the release of these minerals from the sodalite cage occurs at a different rate compared with the dissolution of the predominant nepheline phase.

  9. Characteristics of high quality sorbent for fluidized bed combustion and problems of maintaining uniform reactivity

    SciTech Connect

    Bain, R.J. . Dept. of Geology)

    1993-03-01

    Fluidized bed combustion of coal is considered one of the more promising clean coal technologies for the future. While much research has gone into the design and operation of FBC units, there is little concern for what characterizes a high quality sorbent and the source of such a sorbent. Carbonate rocks, limestone and dolomite, have been tested extensively as sorbents and primarily two rock characteristics appear to significantly control reactivity: composition and texture. Calcium carbonate is more reactive than magnesium carbonate where all other rock characteristics are the same. In considering texture, highest reactivity is measured for carbonate rocks which consist of homogeneous, euhedral crystals ranging in size from .05 to .2 mm and which possess uniform intercrystalline porosity. The most reactive material possesses both high calcium content, uniform microcrystalline texture and intercrystalline porosity, however, such material is not very abundant in nature and is not locally available to midcontinent facilities. Sucrosic dolomite, which possesses uniform microcrystalline texture and intercrystalline porosity has high rank reactivity. While this rock is quite common, it occurs as beds, generally less than twenty feet thick, interlayered with less reactive dolomite types. Therefore, without selective quarrying methods, production of sorbent with uniformly high reactivity will be impossible.

  10. Characterization and Leaching Tests of the Fluidized Bed Steam Reforming (FBSR) Waste Form for LAW Immobilization

    SciTech Connect

    Neeway, James J.; Qafoku, Nikolla; Brown, Christopher F.; Peterson, Reid A.

    2013-10-01

    Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) have been evaluated. One such immobilization technology is the Fluidized Bed Steam Reforming (FBSR) granular product. The FBSR granular product is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals. Production of the FBSR mineral product has been demonstrated both at the industrial and laboratory scale. Pacific Northwest National Laboratory (PNNL) was involved in an extensive characterization campaign. This goal of this campaign was study the durability of the FBSR mineral product and the mineral product encapsulated in a monolith to meet compressive strength requirements. This paper gives an overview of results obtained using the ASTM C 1285 Product Consistency Test (PCT), the EPA Test Method 1311 Toxicity Characteristic Leaching Procedure (TCLP), and the ASTMC 1662 Single-Pass Flow-Through (SPFT) test. Along with these durability tests an overview of the characteristics of the waste form has been collected using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), microwave digestions for chemical composition, and surface area from Brunauer, Emmett, and Teller (BET) theory.

  11. Simulation for Supporting Scale-Up of a Fluidized Bed Reactor for Advanced Water Oxidation

    PubMed Central

    Abdul Raman, Abdul Aziz; Daud, Wan Mohd Ashri Wan

    2014-01-01

    Simulation of fluidized bed reactor (FBR) was accomplished for treating wastewater using Fenton reaction, which is an advanced oxidation process (AOP). The simulation was performed to determine characteristics of FBR performance, concentration profile of the contaminants, and various prominent hydrodynamic properties (e.g., Reynolds number, velocity, and pressure) in the reactor. Simulation was implemented for 2.8 L working volume using hydrodynamic correlations, continuous equation, and simplified kinetic information for phenols degradation as a model. The simulation shows that, by using Fe3+ and Fe2+ mixtures as catalyst, TOC degradation up to 45% was achieved for contaminant range of 40–90 mg/L within 60 min. The concentration profiles and hydrodynamic characteristics were also generated. A subsequent scale-up study was also conducted using similitude method. The analysis shows that up to 10 L working volume, the models developed are applicable. The study proves that, using appropriate modeling and simulation, data can be predicted for designing and operating FBR for wastewater treatment. PMID:25309949

  12. Performance analysis of RDF gasification in a two stage fluidized bed-plasma process.

    PubMed

    Materazzi, M; Lettieri, P; Taylor, R; Chapman, C

    2016-01-01

    The major technical problems faced by stand-alone fluidized bed gasifiers (FBG) for waste-to gas applications are intrinsically related to the composition and physical properties of waste materials, such as RDF. The high quantity of ash and volatile material in RDF can provide a decrease in thermal output, create high ash clinkering, and increase emission of tars and CO2, thus affecting the operability for clean syngas generation at industrial scale. By contrast, a two-stage process which separates primary gasification and selective tar and ash conversion would be inherently more forgiving and stable. This can be achieved with the use of a separate plasma converter, which has been successfully used in conjunction with conventional thermal treatment units, for the ability to 'polish' the producer gas by organic contaminants and collect the inorganic fraction in a molten (and inert) state. This research focused on the performance analysis of a two-stage fluid bed gasification-plasma process to transform solid waste into clean syngas. Thermodynamic assessment using the two-stage equilibrium method was carried out to determine optimum conditions for the gasification of RDF and to understand the limitations and influence of the second stage on the process performance (gas heating value, cold gas efficiency, carbon conversion efficiency), along with other parameters. Comparison with a different thermal refining stage, i.e. thermal cracking (via partial oxidation) was also performed. The analysis is supported by experimental data from a pilot plant.

  13. Gasification of torrefied Miscanthus × giganteus in an air-blown bubbling fluidized bed gasifier.

    PubMed

    Xue, G; Kwapinska, M; Horvat, A; Kwapinski, W; Rabou, L P L M; Dooley, S; Czajka, K M; Leahy, J J

    2014-05-01

    Torrefaction is suggested to be an effective method to improve the fuel properties of biomass and gasification of torrefied biomass should provide a higher quality product gas than that from unprocessed biomass. In this study, both raw and torrefied Miscanthus × giganteus (M×G) were gasified in an air-blown bubbling fluidized bed (BFB) gasifier using olivine as the bed material. The effects of equivalence ratio (ER) (0.18-0.32) and bed temperature (660-850°C) on the gasification performance were investigated. The results obtained suggest the optimum gasification conditions for the torrefied M × G are ER 0.21 and 800°C. The product gas from these process conditions had a higher heating value (HHV) of 6.70 MJ/m(3), gas yield 2m(3)/kg biomass (H2 8.6%, CO 16.4% and CH4 4.4%) and cold gas efficiency 62.7%. The comparison between raw and torrefied M × G indicates that the torrefied M × G is more suitable BFB gasification.

  14. Performance analysis of RDF gasification in a two stage fluidized bed-plasma process.

    PubMed

    Materazzi, M; Lettieri, P; Taylor, R; Chapman, C

    2016-01-01

    The major technical problems faced by stand-alone fluidized bed gasifiers (FBG) for waste-to gas applications are intrinsically related to the composition and physical properties of waste materials, such as RDF. The high quantity of ash and volatile material in RDF can provide a decrease in thermal output, create high ash clinkering, and increase emission of tars and CO2, thus affecting the operability for clean syngas generation at industrial scale. By contrast, a two-stage process which separates primary gasification and selective tar and ash conversion would be inherently more forgiving and stable. This can be achieved with the use of a separate plasma converter, which has been successfully used in conjunction with conventional thermal treatment units, for the ability to 'polish' the producer gas by organic contaminants and collect the inorganic fraction in a molten (and inert) state. This research focused on the performance analysis of a two-stage fluid bed gasification-plasma process to transform solid waste into clean syngas. Thermodynamic assessment using the two-stage equilibrium method was carried out to determine optimum conditions for the gasification of RDF and to understand the limitations and influence of the second stage on the process performance (gas heating value, cold gas efficiency, carbon conversion efficiency), along with other parameters. Comparison with a different thermal refining stage, i.e. thermal cracking (via partial oxidation) was also performed. The analysis is supported by experimental data from a pilot plant. PMID:26184896

  15. Cartesian grid simulations of bubbling fluidized beds with a horizontal tube bundle

    SciTech Connect

    Li, Tingwen; Dietiker, Jean-Francois; Zhang, Yongmin; Shahnam, Mehrdad

    2011-12-01

    In this paper, the flow hydrodynamics in a bubbling fluidized bed with submerged horizontal tube bundle was numerically investigated with an open-source code: Multiphase Flow with Interphase eXchange (MFIX). A newly implemented cut-cell technique was employed to deal with the curved surface of submerged tubes. A series of 2D simulations were conducted to study the effects of gas velocity and tube arrangement on the flow pattern. Hydrodynamic heterogeneities on voidage, particle velocity, bubble fraction, and frequency near the tube circumferential surface were successfully predicted by this numerical method, which agrees qualitatively with previous experimental findings and contributes to a sounder understanding of the non-uniform heat transfer and erosion around a horizontal tube. A 3D simulation was also conducted. Significant differences between 2D and 3D simulations were observed with respect to bed expansion, bubble distribution, voidage, and solids velocity profiles. Hence, the 3D simulation is needed for quantitative prediction of flow hydrodynamics. On the other hand, the flow characteristics and bubble behavior at the tube surface are similar under both 2D and 3D simulations as far as the bubble frequency and bubble phase fraction are concerned. Comparison with experimental data showed that qualitative agreement was obtained in both 2D and 3D simulations for the bubble characteristics at the tube surface.

  16. Characterization of hydrodynamics and solids mixing in fluidized beds involving biomass

    NASA Astrophysics Data System (ADS)

    Fotovat, Farzam

    This thesis focuses on the characterization of hydrodynamics and mixing phenomena in fluidized beds containing mixtures of sand and irregular biomass particles. The first objective of this study is understanding the effect of the large biomass particles on the bubbling characteristics and gas distribution pattern of sand fluidized beds. The second objective is the characterization of mixing/segregation of biomass and sand particles under fluidization conditions. A variety of experimental techniques are employed to study the behavior of two constituting phases of a fluidized bed, i.e., dilute (bubble) and dense (emulsion) phases. Exploring the characteristic fluidization velocities of sand-biomass mixtures unveils that the onset of bubbling in these systems occurs at a higher gas velocity compared to that of the initial fluidization velocity (Uif). The initial bubbling velocity (Uib), the final fluidization velocity ( Uff), and the transition gas velocity from bubbling to turbulent regime (Uc) rise by increasing the fraction of biomass in the mixture. Statistical analysis of the pressure signal at top of the bed reveals that increasing the biomass load hinders the evolution of bubbles at a low gas velocity (U<0.6 m/s), while at high velocities, the bubbling trend of beds containing different fractions of biomass is comparable. The addition of biomass particles to a bed of sand leads to an increase in the mean voidage of the bed; however, the voidage of each phase remains unaffected. It is observed that large biomass particles trigger a break-up of the bubbles, which results in boosting bubbling frequency. The fraction of bubbles at the center of the bed increases with the load of biomass. At the wall region, however, it starts to decrease by adding 2% wt. biomass to pure sand and then increases with the further addition of biomass. The Radioactive Particle Tracking (RPT) technique is implemented in the second section of this work to study the motion and distribution

  17. FLUIDIZED BED STEAM REFORMER (FBSR) PRODUCT: MONOLITH FORMATION AND CHARACTERIZATION

    SciTech Connect

    Jantzen, C

    2006-09-13

    The most important requirement for Hanford's low activity waste (LAW) form for shallow land disposal is the chemical durability of the product. A secondary, but still essential specification, is the compressive strength of the material with regards to the strength of the material under shallow land disposal conditions, e.g. the weight of soil overburden and potential intrusion by future generations, because the term ''near-surface disposal'' indicates disposal in the uppermost portion, or approximately the top 30 meters, of the earth's surface. The THOR{reg_sign} Treatment Technologies (TTT) mineral waste form for LAW is granular in nature because it is formed by Fluidized Bed Steam Reforming (FBSR). As a granular product it has been shown to be as durable as Hanford's LAW glass during testing with ASTM C-1285-02 known as the Product Consistency Test (PCT) and with the Single Pass Flow Through Test (SPFT). Hanford Envelope A and Envelope C simulants both performed well during PCT and SPFT testing and during subsequent performance assessment modeling. This is partially due to the high aluminosilicate content of the mineral product which provides a natural aluminosilicate buffering mechanism that inhibits leaching and is known to occur in naturally occurring aluminosilicate mineral analogs. In order for the TTT Na-Al-Si (NAS) granular mineral product to meet the compressive strength requirements (ASTM C39) for a Hanford waste form, the granular product needs to be made into a monolith or disposed of in High Integrity Containers (HIC's). Additionally, the Hanford intruder scenario for disposal in the Immobilized Low Activity Waste (ILAW) trench is mitigated as there is reduced intruder exposure when a waste form is in a monolithic form. During the preliminary testing of a monolith binder for TTT's FBSR mineral product, four parameters were monitored: (1) waste loading (not optimized for each waste form tested); (2) density; (3) compressive strength; and (4) durability

  18. A MODEL FOR FINE PARTICLE AGGLOMERATION IN CIRCULATING FLUIDIZED BED ABSORBERS

    EPA Science Inventory

    A model for fine particle agglomeration in circulating fluidized bed absorbers (CFBAS) has been developed. It can model the influence of different factors on agglomeration, such as the geometry of CFBAs, superficial gas velocity, initial particle size distribution, and type of ag...

  19. FLUIDIZED BED STEAM REFORMING FOR TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE

    SciTech Connect

    HEWITT WM

    2011-04-08

    This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of fluidized bed steam reforming and its possible application to treat and immobilize Hanford low-activity waste.

  20. Catalytic fast pyrolysis of white oak wood in-situ using a bubbling fluidized bed reactor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Catalytic fast pyrolysis was performed on white oak wood using two zeolite-type catalysts as bed material in a bubbling fluidized bed reactor. The two catalysts chosen, based on a previous screening study, were Ca2+ exchanged Y54 (Ca-Y54) and a proprietary ß-zeolite type catalyst (catalyst M) both ...

  1. Experimental development of a two-stage fluidized-bed/cyclonic agglomerating incinerator

    SciTech Connect

    Mensinger, M.C.; Rehmat, A.; Bryan, B.G.; Lau, F.S. ); Shearer, T.L. ); Duggan, P.A. )

    1991-01-01

    The Institute of Gas Technology (IGT) is conducting an experimental program to develop and test through pilot-plant scale of operation, IGT's two-stage fluidized-bed/cyclonic agglomerating incinerator (TSI). The TSI is based on combining the fluidized-bed agglomeration/gasification technology and the cyclonic combustion/incineration technology, which have been developed at IGT over many years. The TSI is a unique and extremely flexible combustor that can operate over a wide range of conditions in the fluidized-bed first stage from low temperature (desorption) to high temperature (agglomeration) including gasification of high-Btu wastes. The TSI can easily and efficiently destroy solid, liquid and gaseous organic wastes, while containing solid inorganic contaminants within an essentially non-leachable glassy matrix, suitable for disposal in an ordinary landfill. This paper presents the results of tests conducted in a batch, fluidized-bed bench-scale unit (BSU) with commercially available clean'' top soil and the same soil spiked with lead and chromium compounds. The objectives of these tests were to determine the operating conditions necessary to achieve soil agglomeration and to evaluate the leaching characteristics of the soil agglomerates formed. 7 refs., 7 figs., 6 tabs.

  2. Investigation of heat transfer and combustion in the advanced fluidized bed combustor (FBC)

    SciTech Connect

    Dr. Seong W. Lee

    1998-10-01

    The objective of this project is to predict the heat transfer and combustion performance in newly-designed fluidized bed combustor (FBC) and to provide the design guide lines and innovative concept for small-scale boiler and furnace. The major accomplishments are summarized.

  3. Industrial Scale Synthesis of Carbon Nanotubes Via Fluidized Bed Chemical Vapor Deposition: A Senior Design Project

    ERIC Educational Resources Information Center

    Smith, York R.; Fuchs, Alan; Meyyappan, M.

    2010-01-01

    Senior year chemical engineering students designed a process to produce 10 000 tonnes per annum of single wall carbon nanotubes (SWNT) and also conducted bench-top experiments to synthesize SWNTs via fluidized bed chemical vapor deposition techniques. This was an excellent pedagogical experience because it related to the type of real world design…

  4. Fuel and ash characterization of Indian coal for their suitability in fluidized bed combustions

    SciTech Connect

    Palit, A.; Mandal, P.K.

    1995-12-31

    The fluidized bed combustion (FBC) technology is now fully recognized and units with high capacity are in operation the world over. In the Indian context, now is the time to exploit the fluidized bed technology for electric power generation, which may nurture the poor grade Indian coal in a better way as compared to that of pulverized fuel fired system. The present paper deals with Indian coals and ash characterization and the effect of various coal properties on combustion in a fluidized bed like moisture, mineral/ash content, volatile matter, maceral structure (petrographic properties), swelling/caking index, ash properties including ash fusion temperature, etc. and their critical discussion based on experimental investigations with Indian coals and also their suitability in FBC. In addition, the experience with a 10 MW FBC unit in India with problems and parameters, some experimental investigations on suitability of Lalmatia coal (Rajmahal coal field) in fluidized bed combustion and pollutant formations vis-a-vis control (NOx, SOx, etc.) have also been discussed.

  5. PARTICLE FLOW, MIXING, AND CHEMICAL REACTION IN CIRCULATING FLUIDIZED BED ABSORBERS

    EPA Science Inventory

    A mixing model has been developed to simulate the particle residence time distribution (RTD) in a circulating fluidized bed absorber (CFBA). Also, a gas/solid reaction model for sulfur dioxide (SO2) removal by lime has been developed. For the reaction model that considers RTD dis...

  6. The Hydrodynamic Stability of a Fluid-Particle Flow: Instabilities in Gas-Fluidized Beds

    ERIC Educational Resources Information Center

    Liu, Xue; Howley, Maureen A.; Johri, Jayati; Glasser, Benjamin J.

    2008-01-01

    A simplified model of an industrially relevant fluid-particle flow system is analyzed using linear stability theory. Instabilities of the uniform state of a fluidized bed are investigated in response to small flow perturbations. Students are expected to perform each step of the computational analysis, and physical insight into key mechanistic…

  7. Effects of using two- versus three-dimensional computational modeling of fluidized beds Part I, hydrodynamics

    SciTech Connect

    Xie, Nan; Battaglia, Francine; Pannala, Sreekanth

    2008-01-01

    Simulations of fluidized beds are performed to study and determine the effect on the use of coordinate systems and geometrical configurations to model fluidized bed reactors. Computational fluid dynamics is employed for an Eulerian-Eulerian model, which represents each phase as an interspersed continuum. The transport equation for granular temperature is solved and a hyperbolic tangent function is used to provide a smooth transition between the plastic and viscous regimes for the solid phase. The aim of the present work is to show the range of validity for employing simulations based on a 2D Cartesian coordinate system to approximate both cylindrical and rectangular fluidized beds. Three different fluidization regimes, bubbling, slugging and turbulent regimes, are investigated and the results of 2D and 3D simulations are presented for both cylindrical and rectangular domains. The results demonstrate that a 2D Cartesian system can be used to successfully simulate and predict a bubbling regime. However, caution must be exercised when using 2D Cartesian coordinates for other fluidized regimes. A budget analysis that explains all the differences in detail is presented in Part II [N. Xie, F. Battaglia, S. Pannala, Effects of Using Two-Versus Three-Dimensional Computational Modeling of Fluidized Beds: Part II, budget analysis, 182 (1) (2007) 14] to complement the hydrodynamic theory of this paper.

  8. Soil Chemistry Still Affected 23 Years After Large Application of Fluidized Bed Material

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to assess the movement of arsenic, aluminum, calcium, copper, iron, lead, magnesium, manganese, mercury and zinc in an old apple (Malus domestica Borkh) orchard that received a one time application of 36 kg/ m2 of fluidized bed combustion material (FBCM) 23 years earlier. S...

  9. ANALYSIS OF AN AEROBIC FLUIDIZED BED REACTOR DEGRADING MTBE AND BTEX AT REDUCED EBCTS

    EPA Science Inventory

    The purpose of this study was to investigate the biodegradation of MTBE and BTEX using a fluidized bed reactor (FBR) with granular activated carbon (GAC) as a biological attachment medium. Batch experiments were run to analyze the MTBE and TBA degradation kinetics of the culture ...

  10. Alkali metal vapor removal from pressurized fluidized-bed combustor flue gas. Annual report, October 1979-September 1980

    SciTech Connect

    Johnson, I.; Swift, W.M.; Lee, S.H.D.

    1980-10-01

    In the application of pressurized fluidized-bed combustion (PFBC) to the generation of electricity, hot corrosion of the gas turbine (downstream from the combustor) by alkali metal compounds is a potential problem. The objective of this investigation is to develop a method for the removal of gaseous alkali metal compounds from the high-pressure high-temperature gas from a PFBC before the gas enters the gas turbine. The use of a granular bed filter, with either diatomaceous earth or activated bauxite as the bed material, is under study. Breakthrough data are reported on the sorption of gaseous NaCl by activated bauxite. Results are reported for the regeneration of activated bauxite using water leaching and a thermal swing method.

  11. Multi-gene genetic programming based predictive models for municipal solid waste gasification in a fluidized bed gasifier.

    PubMed

    Pandey, Daya Shankar; Pan, Indranil; Das, Saptarshi; Leahy, James J; Kwapinski, Witold

    2015-03-01

    A multi-gene genetic programming technique is proposed as a new method to predict syngas yield production and the lower heating value for municipal solid waste gasification in a fluidized bed gasifier. The study shows that the predicted outputs of the municipal solid waste gasification process are in good agreement with the experimental dataset and also generalise well to validation (untrained) data. Published experimental datasets are used for model training and validation purposes. The results show the effectiveness of the genetic programming technique for solving complex nonlinear regression problems. The multi-gene genetic programming are also compared with a single-gene genetic programming model to show the relative merits and demerits of the technique. This study demonstrates that the genetic programming based data-driven modelling strategy can be a good candidate for developing models for other types of fuels as well.

  12. Single Pass Flow-Through (SPFT) Test Results of Fluidized Bed Steam Reforming (FBSR) Waste Forms used for LAW Immobilization

    SciTech Connect

    Neeway, James J.; Qafoku, Nikolla; Williams, Benjamin D.; Valenta, Michelle M.; Cordova, Elsa A.; Strandquist, Sara C.; Dage, DeNomy C.; Brown, Christopher F.

    2012-03-20

    Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) are being evaluated. One such immobilization technology being considered is the Fluidized Bed Steam Reforming (FBSR) granular product. The FBSR granular product is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals. Production of the FBSR mineral product has been demonstrated both at the industrial and laboratory scale. Single-Pass Flow-Through (SPFT) tests at various flow rates have been conducted with the granular products fabricated using these two methods. Results show that the materials exhibit a relatively low forward dissolution rate on the order of 10-3 g/(m2d) with the material made in the laboratory giving slightly higher values.

  13. Fluidized-Bed Waste-Heat Recovery System development. Semiannual report, 1 August 1981-31 January 1982

    SciTech Connect

    Cole, W. E.; DeSaro, R.; Joshi, C.

    1982-02-01

    The Fluidized-Bed Waste-Heat Recovery (FBWHR) System is designed to preheat this combustion air using the heat available in dirty flue gas streams. In this system, a recirculating medium is heated by the flue gas in a fluidized bed. The hot medium is then removed from the bed and placed in a second fluidized bed where it is fluidized by the combustion air. Through this process, the combustion air is heated. The cooled medium is then returned to the first bed. Initial development of this concept is for the aluminum smelting industry.

  14. Neural network-based monitoring and control of fluidized bed. Quarterly progress report, July 1995--September 1995

    SciTech Connect

    Bodruzzaman, M.

    1995-09-27

    This report is to review the work done for the fluidized bed combustion (FBC) project in the past three months, and introduce a general research plan for the next six months. In the last two months, a literature review has been performed on most of the previous work done in the areas of chaotic system analysis, chaotic system identification, chaotic system control, neural network models for non-linear and chaotic systems, fluidized bed behavior analysis, and fluidized bed behavior modeling and control. A clear view has been developed on the status of the FBC technology and the main problems that need to be solved.

  15. Fluidized-Bed Waste-Heat Recovery System development. Semiannual report, 1 August 1982-31 January 1983

    SciTech Connect

    Cole, W.E.; DeSaro, R.; Joshi, C.

    1983-02-01

    The Fluidized-Bed Waste-Heat Recovery (FBWHR) System is designed to preheat this combustion air using the heat available in dirty flue gas streams. In this system, a recirculating medium is heated by the flue gas in a fluidized bed. The hot medium is then removed from the bed and placed in a second fluidized bed where it is fluidized by the combustion air. Through this process, the combustion air is heated. The cooled medium is then returned to the first bed. Initial development of this concept is for the aluminum smelting industry.

  16. Radiative heat transfer in strongly forward scattering media of circulating fluidized bed combustors

    NASA Astrophysics Data System (ADS)

    Ates, Cihan; Ozen, Guzide; Selçuk, Nevin; Kulah, Gorkem

    2016-10-01

    Investigation of the effect of particle scattering on radiative incident heat fluxes and source terms is carried out in the dilute zone of the lignite-fired 150 kWt Middle East Technical University Circulating Fluidized Bed Combustor (METU CFBC) test rig. The dilute zone is treated as an axisymmetric cylindrical enclosure containing grey/non-grey, absorbing, emitting gas with absorbing, emitting non/isotropically/anisotropically scattering particles surrounded by grey diffuse walls. A two-dimensional axisymmetric radiation model based on Method of Lines (MOL) solution of Discrete Ordinates Method (DOM) coupled with Grey Gas (GG)/Spectral Line-Based Weighted Sum of Grey Gases Model (SLW) and Mie theory/geometric optics approximation (GOA) is extended for incorporation of anisotropic scattering by using normalized Henyey-Greenstein (HG)/transport approximation for the phase function. Input data for the radiation model is obtained from predictions of a comprehensive model previously developed and benchmarked against measurements on the same CFBC burning low calorific value indigenous lignite with high volatile matter/fixed carbon (VM/FC) ratio in its own ash. Predictive accuracy and computational efficiency of nonscattering, isotropic scattering and forward scattering with transport approximation are tested by comparing their predictions with those of forward scattering with HG. GG and GOA based on reflectivity with angular dependency are found to be accurate and CPU efficient. Comparisons reveal that isotropic assumption leads to under-prediction of both incident heat fluxes and source terms for which discrepancy is much larger. On the other hand, predictions obtained by neglecting scattering were found to be in favorable agreement with those of forward scattering at significantly less CPU time. Transport approximation is as accurate and CPU efficient as HG. These findings indicate that negligence of scattering is a more practical choice in solution of the radiative

  17. Bed hydrodynamics and heat transfer to tubes in the freeboard region of a pressurized fluidized-bed coal combustor

    SciTech Connect

    Sellakumar, K.M.

    1988-01-01

    Various modes of Pressurized Fluidized Bed Combustor part-load operation are analyzed. Bed change is considered to be the most effective of these methods. The need to understand the variation in heat absorption by exposed in-bed tubes immediately above the reducing or increasing bed height has resulted in the pursuit for a clearer understanding of the particle concentration profile and heat transfer mechanisms to the referred tubes. Bubble characteristics in a PFBC with internals are studied in depth. A model for gas flow through dense and bubble phases is developed. Model results are compared with the limited experimental results available in literature. For both atmospheric and pressurized fluidized bed combustors, the deviation from the two phase theory is highlighted; and this simple model approach has evolved a procedure to quantify gas flows in different streams which was thus far available only qualitatively. The dense phase velocity is found to be much more than the minimum fluidization velocity. A theoretical model for particle efflux from the bed top surface has been evolved. An empirical model has also been developed for elutriant flux above the Transport Disengagement Height, the concentration of fines in the efflux material, superficial velocity in the freeboard, and mean particle terminal velocity have appeared to be the major factors influencing the carry over. The model developed using the data form a smaller rectangular rest rig was tested satisfactorily with the limited data from a larger as well as a similar size circular unit. If the particulate loading profile above the bed surface is known, then the heat transfer to the heat exchanger surfaces may be obtained from the available correlations.

  18. In-situ treatment of acid mine waters using fluidized bed ash: Field study

    SciTech Connect

    Everett, J.W.; Canty, G.A.

    1999-07-01

    A slurry of mine water and fluidized bed ash (FBA) was injected into an abandoned coal mine in eastern Oklahoma in July 1997. Oil-field technology was used to inject 1.8 Gg (418 tons) of FBA through five wells in 15 hours. Prior to injection the seep water had a pH of 4.4, was net acidic (acidity over 400 mg/L as CaCO{sub 3}), and had relatively high metal concentrations (in mg/L: Fe-200; Mn-7; and Al-6). After injection, during the period of effective treatment, the seep water had a pH above 6.0, less net acidity, and had lower metals concentrations (in mg/L: Fe-120; Mn-5; and Al-{lt}PQL). When the treated seep water exited the mine, the dissolved metals oxidized and hydrolyzed. As the metals precipitated, the alkalinity introduced by the FBA was consumed and the pH dropped. However, the seep water characteristics upon entering the receiving stream were improved, compared to pre-injection. The resulting seep water quality is such that it is more amenable to further treatment by passive treatment methods, such as anoxic limestone drains or wetlands. Alkaline injection is a finite treatment process. Eventually, the added alkalinity is exhausted, at which time the seep returns to pre-injection conditions, necessitating another injection of ash. For the study discussed in this paper, the treatment lasted approximately 15 months. While the amount of alkalinity added to the mine could have potentially treated much more than a year's volume of seep water, it is believed that much of the injected alkalinity was unavailable in backwater areas in the mine. This alkalinity contributed little, if any, to the treatment of water flowing through the mine. Mine hydrology, especially during injection are crucial to treatment longevity.

  19. Extracting Oxygen from Lunar Simulant Using a Transparent Furnace Pulsed Fluidized Bed

    NASA Technical Reports Server (NTRS)

    Oryshchyn, L.; Paz, A.; Lee, K.; Reddington, M.

    2010-01-01

    In the event that humans return to the moon, utilizing the local materials will be beneficial for extended stays. Rather than transporting resources, such as oxygen, from Earth, NASA is investigating methods of extracting it from lunar regolith. One promising process is hydrogen reduction. In the hydrogen reduction process, lunar regolith is heated to 1000 C in the presence of hydrogen. The iron oxide (Fe-O) bonds, found in lunar material, are broken and the hydrogen attracts the oxygen to produce water vapor [Allen et al., 1996]. FeO + H2 (right arrow) Fe +H2O. The water vapor is then captured, cleaned, and electrolyzed. The hydrogen is recycled back to the reduction process and the oxygen is stored until consumed by an end user (propulsion, life support, etc.). To obtain a good oxygen yield, the majority of lunar regolith must be exposed to the hydrogen gas and have a high rate of heat transfer from heat source to particle. This is achieved with good solids mixing via fluidization or mechanical agitation. In Generation II of the ROxygen program, the ROxygen Team at Johnson Space Center (JSC) investigated the feasibility of gas only pulsed fluidization as the only means to mix synthetic lunar regolith (simulant) at high temperatures. Fluidized beds have been used in industry to effectively process powders for decades. They consist of gas flowing upward through a bed of particles. The stirring action continuously moves the grains around to achieve uniform mixing of gas, solids, and heat [Geldart, 1986]. A transparent furnace unit was developed by Thoughventions Unlimited LLC (TvU) to aid in the qualitative observation of the fluidization behavior at high temperatures. Multipoint thermocouples and pressure sensors provided quantitative information regarding the quality of mixing. The water produced was measured using humidity sensors and captured using a NASA designed and built condenser. Once the simulant was processed, pneumatically transporting the 'hot' simulant

  20. High-sulfate, high-chemical oxygen demand wastewater treatment using aerated methanogenic fluidized beds

    SciTech Connect

    Zitomer, D.H.; Shrout, J.D.

    2000-02-01

    Many industrial wastewaters have both high organic pollution and sulfate (SO{sub 4}{sup {minus}2}) concentrations. Although biological conversion of organics to methane may be an economical chemical oxygen demand (COD) removal option, significant inhibition of methane production results from reduction of SO{sub 4}{sup {minus}2} to hydrogen sulfide (H{sub 2}S), which is inhibitory to methanogenic microorganisms. Therefore, sulfate-containing wastewater is often not amenable to conventional anaerobic treatment. Recently, limited aeration of recycle flow to hybrid and baffled reactors has been used to treat this wastewater and has been shown to reduce aqueous H{sub 2}S concentrations by causing production of uninhibitory sulfur (S{degree}) and thiosulfate (S{sub 2}O{sub 3}{sup {minus}2}) as well as gas stripping volatile H{sub 2}S. In this study, directly aerated methanogenic fluidized bed reactors (FBRs) achieved increased methane production compared to strictly anaerobic FBRs treating high-sulfate wastewater. Oxygen transfer satisfying up to 28% of the COD load resulted in maximum specific oxygen utilization rates of 0.20 mg oxygen/g volatile solids{center{underscore}dot}min, with significant, concomitant methane production. Under typically inhibitory SO{sub 4}{sup {minus}2} loading, higher aeration caused increased effluent SO{sub 4}{sup {minus}2}, increased H{sub 2}S mass in the offgas, and lower reactor H{sub 2}S concentration. As a result, COD removal increased from 25% for a strictly anaerobic FBR to 87% for an aerated FBR. In addition, aerated systems required significantly less alkalinity supplementation to maintain a pH value of 7, ostensibly because of stripping of acidic carbon dioxide. The potential pH increase associated with aeration also shifts sulfide speciation to less toxic disulfide. Direct, limited aeration of methanogenic FBRs is described as a method for increased COD removal when treating high-COD, high-sulfate wastewater.

  1. Coal slurry solids/coal fluidized bed combustion by-product mixtures as plant growth media

    USGS Publications Warehouse

    Darmody, R.G.; Green, W.P.; Dreher, G.B.

    1998-01-01

    Fine-textured, pyritic waste produced by coal cleaning is stored in slurry settling ponds that eventually require reclamation. Conventionally, reclamation involves covering the dewatered coal slurry solids (CSS) with 1.3 m of soil to allow plant growth and prevent acid generation by pyrite oxidation. This study was conducted to determine the feasiblity of a less costly reclamation approach that would eliminate the soil cover and allow direct seeding of plants into amended CSS materials. Potential acidity of the CSS would be neutralized by additions of fluidized-bed combustion by-product (FBCB), an alkaline by-product of coal combustion. The experiment involved two sources of CSS and FBCB materials from Illinois. Birdsfoot trefoil (Lotus corniculatus L.), tall fescue (Festuca arundinacea Schreb.), and sweet clover (Melilotus officinalis (L.) Lam.) were seeded in the greenhouse into pots containing mixtures of the materials. CSS-1 had a high CaCO3:FeS2 ratio and needed no FBCB added to compensate for its potential acidity. CSS-2 was mixed with the FBCB materials to neutralize potential acidity (labeled Mix A and B). Initial pH was 5.6, 8.8, and 9.2 for the CSS-1, Mix A, and Mix B materials, respectively. At the end of the 70-day experiment, pH was 5.9 for all mixtures. Tall fescue and sweet clover grew well in all the treatments, but birdsfoot trefoil had poor emergence and survival. Elevated tissue levels of B, Cd, and Se were found in some plants. Salinity, low moisture holding capacity, and potentially phytotoxic B may limit the efficacy of this reclamation method.

  2. Microstructure of multicrystalline silicon seeded by polysilicon chips and fluidized bed reactor granules

    NASA Astrophysics Data System (ADS)

    Ekstrøm, K. E.; Stokkan, G.; Autruffe, A.; Søndenå, R.; Dalaker, H.; Arnberg, L.; Di Sabatino, M.

    2016-05-01

    Multicrystalline silicon displays a considerable smaller average grain size and reduced dislocation generation when being seeded by polycrystalline silicon chips or fluidized bed reactor silicon granules. A simple texture analysis shows how the initially random grain structure of the seeds develops a weak preference for near-<111> and near-<112> oriented grains upwards in the ingot. Closer investigations reveal a considerable coarsening of the initial microstructure of the seeds during the directional solidification process, especially for small fluidized bed reactor granules. The irregular shape of polysilicon chips allows for melt penetration into the seeding structure and potential indentation effects that may account for the increased dislocation generation observed in this case. The increased generation may, however, also be related to a higher ratio of ∑27 grain boundaries.

  3. Metal wastage design guidelines for bubbling fluidized-bed combustors. Final report

    SciTech Connect

    Lyczkowski, R.W.; Podolski, W.F.; Bouillard, J.X.; Folga, S.M.

    1992-11-01

    These metal wastage design guidelines identify relationships between metal wastage and (1) design parameters (such as tube size, tube spacing and pitch, tube bundle and fluidized-bed height to distributor, and heat exchanger tube material properties) and (2) operating parameters (such as fluidizing velocity, particle size, particle hardness, and angularity). The guidelines are of both a quantitative and qualitative nature. Simplified mechanistic models are described, which account for the essential hydrodynamics and metal wastage processes occurring in bubbling fluidized beds. The empirical correlational approach complements the use of these models in the development of these design guidelines. Data used for model and guideline validation are summarized and referenced. Sample calculations and recommended design procedures are included. The influences of dependent variables on metal wastage, such as solids velocity, bubble size, and in-bed pressure fluctuations, are discussed.

  4. Proceedings of the sixth international conference on fluidized bed combustion. Volume II. Technical sessions

    SciTech Connect

    1980-08-01

    The Sixth International Conference on Fluidized Bed Combustion was held April 9-11, 1980, at the Atlanta Hilton, Atlanta, Georgia. It was sponsored by the US Department of Energy, the Electric Power Research Institute, the US Environmental Protection Agency, and the Tennessee Valley Authority. The papers covered recent developments in atmospheric and pressurized fluidized-bed combustion, especially the design, operation and control of pilot and demonstration plants. The cleanup of combustion products and the erosion, corrosion and fouling of gas turbines was emphasized also. Fifty-five papers from Volume 2 of the proceedings have been entered individually into EDB and ERA; five papers had been entered previously from other sources. (LTN)

  5. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Kunlei Liu; John T. Riley

    2004-01-01

    The purpose of this report is to summarize the progress made on the project ''Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion (CFBC) System'' in this quarter (September-December of 2003). The main tasks in this quarter consisted of the following four parts. First, all documents for managing this project have been prepared and sent to the Office of Project Management at the US Department of Energy's (DOE's) National Energy Technology Laboratory (NETL). Second, plans for the renovation of space for a new combustion laboratory for the CFBC system has progressed smoothly. Third, considerable progress in the design of the CFBC system has been made. Finally, a lab-scale simulated fluidized-bed combustion facility has been set up in order to make some fundamental investigations of the co-firing of coal with waste materials in the next quarter. Proposed work for the next quarter has been outlined in this report.

  6. Combustion Characteristics of Lignite Char in a Laboratory-scale Pressurized Fluidized Bed Combustor

    NASA Astrophysics Data System (ADS)

    Murakami, Takahiro; Suzuki, Yoshizo

    In a dual fluidized bed gasifier, the residual char after steam gasification is burnt in riser. The objectives of this work are to clarify the effect of parameters (temperature, pressure, and particle size of lignite char) of char combustion using a laboratory-scale pressurized fluidized bed combustor (PFBC). As a result, the burnout time of lignite char can be improved with increasing operating pressure, and temperature. In addition, the decrease in the particle size of char enhanced the effect on burnout time. The initial combustion rate of the char can be increased with increasing operating pressure. The effect was decreased with increasing operating temperature. However, the effect of operating pressure was slightly changed in small particle size, such as 0.5-1.0 mm. It takes about 20 sec to burn 50% of char in the operating pressure of 0.5 MPa and the particle size of 0.5-1.0 mm.

  7. West Virginia Geological Survey's role in siting fluidized bed combustion facilities

    USGS Publications Warehouse

    Smith, C.J.; King, Hobart M.; Ashton, K.C.; Kirstein, D.S.; McColloch, G.H.

    1989-01-01

    A project is presented which demonstrates the role of geology in planning and siting a fluidized bed combustion facility. Whenever a project includes natural resource utilization, cooperation between geologists and design engineers will provide an input that could and should save costs, similar to the one stated in our initial premise. Regardless of whether cost reductions stem from a better knowledge of fuel and sorbent availabilities, or a better understanding of the local hydrology, susceptibility to mine-subsidence, or other geologic hazards, the geological survey has a vital role in planning. Input to planning could help the fluidized-bed developer and design-engineer solve some economic questions and stretch the financial resources at their disposal.

  8. Fluctuations, Stratification and Stability in a Liquid Fluidized Bed at Low Reynolds Number

    NASA Technical Reports Server (NTRS)

    Segre, P. N.; McClymer, J. P.

    2004-01-01

    The sedimentation dynamics of extremely low polydispersity, non-colloidal, particles are studied in a liquid fluidized bed at low Reynolds number, Re much less than 1. When fluidized, the system reaches a steady state, defined where the local average volume fraction does not vary in time. In steady state, the velocity fluctuations and the particle concentrations are found to strongly depend on height. Using our results, we test a recently developed stability model for steady state sedimentation. The model describes the data well, and shows that in steady state there is a balancing of particle fluxes due to the fluctuations and the concentration gradient. Some results are also presented for the dependence of the concentration gradient in fluidized beds on particle size; the gradients become smaller as the particles become larger and fewer in number.

  9. Development of a bioreactor based on magnetically stabilized fluidized bed for bioartificial liver.

    PubMed

    Deng, Fei; Chen, Li; Zhang, Ying; Zhao, Shan; Wang, Yu; Li, Na; Li, Shen; Guo, Xin; Ma, Xiaojun

    2015-12-01

    Bioartificial liver (BAL) based on microcapsules has been proposed as a potential treatment for acute liver failure. The bioreactors used in such BAL are usually expected to achieve sufficient flow rate and minimized void volume for effective application. Due to the superiorities in bed pressure drop and operation velocity, magnetically stabilized fluidized beds (MSFBs) show the potential to serve as ideal microcapsule-based bioreactors. In the present study, we attempted to develop a microcapsule-based MSFB bioreactor for bioartificial liver device. Compared to conventional-fluidized bed bioreactors, the bioreactor presented here increased perfusion velocity and decreased void volume significantly. Meanwhile, the mechanical stability as well as the immunoisolation property of magnetite microcapsules were well maintained during the fluidization. Besides, the magnetite microcapsules were found no toxicity to cell survival. Therefore, our study might provide a novel approach for the design of microcapsule-based bioartificial liver bioreactors.

  10. The development of a fluidized bed process for the heat treatment of aluminum alloys

    NASA Astrophysics Data System (ADS)

    Keist, Jay

    2005-04-01

    Heat treating of aluminum alloys is often necessary to achieve the mechanical properties required for a part. With conventional furnaces, though, the heat-treating process requires several hours and manufacturers have traditionally utilized off-line, batch heat-treating operations. The long cycle times required for heat treating with conventional systems go contrary to lean manufacturing where the goal is to reduce the time a part spends in the factory. The fluidized bed technology offers rapid heating rates and excellent temperature control that allows one to significantly reduce the time required for heat treating by an order of magnitude. Technomics developed a fluidized bed conveying system that allows the manufacturer to bring the heat-treating system in-line with the casting or forging operation, obtaining a true lean manufacturing process.

  11. Numerical Simulation of Sludge Dryness under Flue Gas Atmosphere in the Riser of a Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Xiao, H. M.; Ma, X. Q.; Liu, K.; Yu, Z. S.

    A numerical algorithm is developed for a detailed 3D simulation of the gas/particle flow behavior used for drying of sludge under flue gas atmosphere in the riser section of a circulating fluidized bed. The gas phase is described with standard κ - ɛ turbulence model, whereas a Lagrangian formulation with a stochastic particle dispersion model is adopted for the particulate phase. Conservation equations of mass and momentum for each phase were solved using the volume numerical technique. Fluid-particle interaction is taken into account to calculate the mass, momentum, and heat transfer between phases. The numerical algorithm is used to predict the circulating fluidized bed performance under various inlet profiles of the flue gas velocity. Gas and particle flow profiles were obtained for velocity and temperature parameters for each phase. The influence of the flue gas inlet velocity and the sludge mass flow rate on drying is discussed.

  12. Experimental studies on combustion of cattle manure in a fluidized bed combustor

    SciTech Connect

    Annamaial, K.; Ibrahim, M.Y.; Sweeten, J.M.

    1987-06-01

    Manure from cattle feedlots is a renewable energy source which has the potential of supplementing the existing fossil fuels. But the heat content of manure is rather low. Since the fluidized bed combustion technology has been used for the energy conversion of marginal fuels, such a technology is being explored for the combustion of feedlot manure. A fluidized bed combustor of 0.15 m (6 in.) diameter was used for the combustion tests on manure. Experiments were conducted with -20 to +20 percent excess air and at bed temperatures ranging from 600/sup 0/C (1112/sup 0/F) to 800/sup 0/C (1472/sup 0/F). Experimental data revealed that the gasification efficiencies ranged from 90 to 98 percent, while the combustion efficiencies varied from 45 to 85 percent.

  13. A model of coal particle drying in fluidized bed combustion reactor

    SciTech Connect

    Komatina, M.; Manovic, V.; Saljnikov, A.

    2007-02-15

    Experimental and theoretical investigation on drying of a single coal particle in fluidized bed combustor is presented. Coal particle drying was considered via the moist shrinking core mechanism. The results of the drying test runs of low-rank Serbian coals were used for experimental verification of the model. The temperature of the coal particle center was measured, assuming that drying was completed when the temperature equalled 100{sup o}C. The influence of different parameters (thermal conductivity and specific heat capacity of coal, fluidized bed temperature, moisture content and superheating of steam) on drying time and temperature profile within the coal particle was analyzed by a parametric analysis. The experimentally obtained results confirmed that the moist shrinking core mechanism can be applied for the mathematical description of a coal particle drying, while dependence between drying time and coal particle radius, a square law relationship, implicates heat transfer control of the process and confirms the validity of assumptions used in modeling.

  14. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Yan Cao; Songgeng Li

    2006-04-01

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2006 through March 31, 2006. Work was performed on the following activities. First, the fabrication and manufacture of the CFBC Facility were completed. The riser, primary cyclone and secondary cyclone of Circulating Fluidized Bed (CFB) Combustor have been erected. Second, the Mercury Control Workshop and the Grand Opening of Institute for Combustion Science and Environmental Technology (ICSET) were successfully held on February 22 and 23, 2006, respectively. Third, effects of hydrogen chlorine (HCl) and sulfur dioxide (SO{sub 2}) on mercury oxidation were studied in a drop tube reactor. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

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

    NASA Astrophysics Data System (ADS)

    1980-05-01

    The feasibility of developing a microwave diagnostic system for measurement of bubbles in a fluidized bed combustion system was 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 is 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.

  16. Preliminary market assessment of fluidized-bed waste-heat recovery technology

    SciTech Connect

    Campos, F.T.; Fey, C.L.; Grogan, P.J.; Klein, N.P.

    1980-06-01

    A preliminary assessment of fluidized-bed waste-heat recovery (FBWHR) system market potential is presented with emphasis on the factors influencing industrial acceptability. Preliminary market potential areas are identified based on the availability of waste heat. Trends in energy use are examined to see the effect they might have on these market potential areas in the future. Focus groups interviews are used to explore important factors in the industrial decision-making process. These important factors are explored quantitatively in a survey of industrial plant engineers. The survey deals with the waste-heat boiler configuration of the FBWHR system. Results indicate market acceptance of the fluidized-bed waste-heat boiler could be quite low.

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

    SciTech Connect

    Not Available

    1980-05-01

    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.

  18. Development of a topping combustor for advanced concept pressurized fluidized-bed combustion systems

    SciTech Connect

    Domeracki, W.F.; Dowdy, T.E.; Bachovchin, D.

    1995-11-01

    A project team consisting of Foster Wheeler Development Corporation, Westinghouse Electric Corporation, Gilbert/Commonwealth and the Institute of Gas Technology, are developing a Second Generation Pressurized Fluidized Bed System. Foster Wheeler is developing a carbonizer (a partial gasifier) and a pressurized fluidized bed combustor. Both these units operate at a nominal 1600{degrees}F (870{degrees}C) for optimal sulfur capture. Since this temperature is well below the current combustion turbine combustor outlet operating temperature of 2350{degrees}F (1290{degrees}C), to reach commercialization, a topping combustor and hot gas cleanup (HGCU) equipment must be developed. Westinghouse`s efforts are focused on the development of the high temperature gas cleanup equipment and the topping combustor. This paper concentrates on the design and test of the topping combustor, which must use a low heating value syngas from the carbonizer at approximately 1600{degrees}F and 150 to 210 psi.

  19. The characteristics of gas-solid flow and wall heat transfer in a fluidized bed reactor

    NASA Astrophysics Data System (ADS)

    Choi, Hang Seok; Meier, Dietrich

    2012-09-01

    Numerical study using computational fluid dynamics has been carried out to investigate the heat transfer characteristics of a laboratory fluidized bed reactor. The fluidized bed reactor of vTI (Johann Heinrich von Thünen-Institute)-Institute of Wood Technology and Wood Biology is modeled. For the simulation of multiphase flow and thermal fields, an Eulerian-Eulerian approach is applied. The flow and thermal characteristics of the reactor are fully investigated for the wide range of superficial gas velocities and two different particle diameters. In particular, the contributions of the gas bubble and emulsion phase flows on the wall heat transfer are scrutinized. From the predicted results, it is fully elucidated that particular near-wall bubble motions mainly govern the wall heat transfer.

  20. Grout stability and strength requirements for field scale injection of fluidized bed combustion ash grout

    SciTech Connect

    Ziemkiewicz, P.F.; Black, C.; Gray, D.D.; Siriwardane, H.J.; Hamric, R.

    1998-12-31

    This paper presents the results of a study involving a field scale injection of a grout made of Fluidized Bed Combustion Ash to control acid mine drainage and subsidence at an abandoned room and pillar coal mine. The grout mix was developed from results obtained from several laboratory scale experiments conducted to investigate flow characteristics and strength of the grout. Based on the rheological properties of the candidate grout mixes it was determined that admixtures were needed to stabilize the grout for optimum flow characteristics. Strength requirements for the grout were determined from site specific geologic information and expected stress levels. One thousand cubic yards of the candidate grout were pumped into an inactive panel of an active room and pillar coal mine to investigate the field performance of the grout. The field study showed that a grout made of Fluidized Bed Combustion ash can be successfully pumped to backfill the mine void.

  1. Performance of the Fluidized Bed Steam Reforming product under hydraulically unsaturated conditions.

    PubMed

    Neeway, James J; Qafoku, Nikolla P; Williams, Benjamin D; Rod, Kenton; Bowden, Mark E; Brown, Christopher F; Pierce, Eric M

    2014-05-01

    Several candidates for supplemental low-activity waste (LAW) immobilization at the Hanford site in Washington State, USA are being considered. One waste sequestering technology considered is Fluidized Bed Steam Reforming (FBSR). The granular product resulting from the FBSR process is composed primarily of an insoluble sodium aluminosilicate matrix with the dominant phases being feldspathoid minerals with a 1:1:1 molar ratio of Na, Al and Si. To demonstrate the durability of the product, which can be disposed of at the unsaturated Integrated Disposal Facility (IDF) at Hanford, a series of tests has been performed using the Pressurized Unsaturated Flow (PUF) system, which allows for the accelerated weathering of the solid materials. The system maintains hydraulically unsaturated conditions, thus mimicking the open-flow and transport properties that will be present at the IDF. Two materials were tested using the system: 1) the FBSR granular product and 2) the FBSR granular product encapsulated in a geopolymer to form a monolith. Results of the experiments show a trend of relatively constant effluent concentration of Na, Si, Al, and Cs as a function of time from both materials. The elements I and Re show a steady release throughout the yearlong test from the granular material but their concentrations seem to be increasing at one year from the monolith material. This result suggests that these two elements may be present in the sodalite cage structure rather than in the predominant nepheline phase because their release occurs at a different rate compared to nepheline phase. Also, these elements to not seem to reprecipitate when released from the starting material. Calculated one-year release rates for Si are on the order of 10(-6) g/(m(2) d) for the granular material and 10(-5) g/(m(2) d) for the monolith material while Re release is seen to be two orders of magnitude higher than Si release rates. SEM imaging and XRD analysis show how the alteration of the two

  2. Performance of the Fluidized Bed Steam Reforming product under hydraulically unsaturated conditions

    SciTech Connect

    Neeway, James J; Rod, Kenton A.; Bowden, Mark E; Pierce, Eric M; Qafoku, Nikolla; Williams, Benjamin D; Brown, Christopher F

    2014-01-01

    Several candidates for supplemental low-activity waste (LAW) immobilization at the Hanford site in Washington State, USA are being considered. One waste sequestering technology considered is Fluidized Bed Steam Reforming (FBSR). The granular product resulting from the FBSR process is composed primarily of an insoluble sodium aluminosilicate matrix with the dominant phases being feldspathoid minerals with a 1:1:1 molar ratio of Na, Al and Si. To demonstrate the durability of the product, which can be disposed of at the unsaturated Integrated Disposal Facility (IDF) at Hanford, a series of tests has been performed using the Pressurized Unsaturated Flow (PUF) system, which allows for the accelerated weathering of the solid materials. The system maintains hydraulically unsaturated conditions, thus mimicking the open-flow and transport properties that will be present at the IDF. Two materials were tested using the system: 1) the FBSR granular product and 2) the FBSR granular product encapsulated in a geopolymer to form a monolith. Results of the experiments show a trend of relatively constant effluent concentration of Na, Si, Al, and Cs as a function of time from both materials. The elements I and Re show a steady release throughout the yearlong test from the granular material but their concentrations seem to be increasing at one year from the monolith material. This result suggests that these two elements may be present in the sodalite cage structure rather than in the predominant nepheline phase because their release occurs at a different rate compared to nepheline phase. Also, these elements to not seem to reprecipitate when released from the starting material. Calculated one-year release rates for Si are on the order of 10 6 g/(m2 d) for the granular material and 10 5 g/(m2 d) for the monolith material while Re release is seen to be two orders of magnitude higher than Si release rates. SEM imaging and XRD analysis show how the alteration of the two materials is

  3. Treatment of cheese whey and soft drink bottling wastes in an anaerboic biological fluidized bed reactor

    SciTech Connect

    Hickey, R.; Owens, R.

    1982-11-01

    This report describes the development of an anaerobic system to produce combustible gas from cheese whey, soft drink bottling plant wastes, and other organic wastes. Experiments conducted using whey and soft drink wastes in a small scale reactor determined the optimum operating conditions to maximize combustible gas yield and minimize operating costs. Economic analyses are presented in the report which demonstrate that anaerobic treatment of these wastes in a fluidized bed reactor is a highly cost-effective process.

  4. Preliminary study of a radiantly heated fluidized bed for the production of high purity silicon

    NASA Technical Reports Server (NTRS)

    Levenspiel, O.; Larson, M.; Zhang, G. T.; Ouyang, F.

    1983-01-01

    The preparation of very pure silicon from silane (SIH4) using radiant heating of the hot silicon particles of a fluidized bed is discussed. The fraction of electrical energy supplied to the heater which is actually absorbed by the particles and the heat transfer coefficient between the hot bed and the cool distributor plate were investigated. The experimental design is presented and the results of the study are summarized.

  5. Design and performance of a fluidized-bed incinerator for TRU combustible wastes

    SciTech Connect

    Meile, L.J.; Meyer, F.G.

    1982-01-01

    Problems encountered in the incineration of glovebox generated waste at Rocky Flats Plant (RFP) led to the development of a fluidized-bed incineration (FBI) system for transuranic (TRU) combustible wastes. Laboratory and pilot-scale testing of the process preceded the installation of an 82-kg/h production demonstration incinerator at RFP. The FBI process is discussed, and the design of the demonstration incinerator is described. Operating experience and process performance for both the pilot and demonstration units are presented.

  6. INVESTIGATION OF FUEL CHEMISTRY AND BED PERFORMANCE IN A FLUIDIZED BED BLACK LIQUOR STEAM REFORMER

    SciTech Connect

    Kevin Whitty

    2003-12-01

    The University of Utah project ''Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer'' (DOE award number DE-FC26-02NT41490) was developed in response to a solicitation for projects to provide technical support for black liquor and biomass gasification. The primary focus of the project is to provide support for a DOE-sponsored demonstration of MTCI's black liquor steam reforming technology at Georgia-Pacific's paper mill in Big Island, Virginia. A more overarching goal is to improve the understanding of phenomena that take place during low temperature black liquor gasification. This is achieved through five complementary technical tasks: (1) construction of a fluidized bed black liquor gasification test system, (2) investigation of bed performance, (3) evaluation of product gas quality, (4) black liquor conversion analysis and modeling and (5) computational modeling of the Big Island gasifier. Four experimental devices have been constructed under this project. The largest facility, which is the heart of the experimental effort, is a pressurized fluidized bed gasification test system. The system is designed to be able to reproduce conditions near the black liquor injectors in the Big Island steam reformer, so the behavior of black liquor pyrolysis and char gasification can be quantified in a representative environment. The gasification test system comprises five subsystems: steam generation and superheating, black liquor feed, fluidized bed reactor, afterburner for syngas combustion and a flue gas cooler/condenser. The three-story system is located at University of Utah's Industrial Combustion and Gasification Research Facility, and all resources there are available to support the research.

  7. Proceedings of the sixth international conference on fluidized bed combustion. Volume III. Technical sessions

    SciTech Connect

    1980-08-01

    The Sixth International Conference on Fluidized Bed Combustion was held April 9-11, 1980, at the Atlanta Hilton, Atlanta, Georgia. It was sponsored by the US Department of Energy, the Electric Power Research Institute, the US Environmental Protection Agency, and the Tennessee Valley Authority. Forty-five papers from Vol. III of the proceedings have been entered individually into EDB and ERA. Two papers had been entered previously from other sources. (LTN)

  8. Pulsed atmospheric fluidized bed combustion. Technical progress report, January 1992--March 1992

    SciTech Connect

    Not Available

    1992-05-01

    During this first quarter, a lab-scale water-cooled pulse combustor was designed, fabricated, and integrated with old pilot-scale PAFBC test systems. Characterization tests on this pulse combustor firing different kinds of fuel -- natural gas, pulverized coal and fine coal -- were conducted (without fluidized bed operation) for the purpose of finalizing PAFBC full-scale design. Steady-state tests were performed. Heat transfer performance and combustion efficiency of a coal-fired pulse combustor were evaluated.

  9. A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems

    PubMed Central

    Li, Jianzhou; Yu, Liang; Chen, Ermei; Zhu, Danhua; Zhang, Yimin; Li, LanJuan

    2016-01-01

    A fluidized bed bioreactor containing encapsulated hepatocytes may be a valuable alternative to a hollow fiber bioreactor for achieving the improved mass transfer and scale-up potential necessary for clinical use. However, a conventional fluidized bed bioreactor (FBB) operating under high perfusion velocity is incapable of providing the desired performance due to the resulting damage to cell-containing microcapsules and large void volume. In this study, we developed a novel diversion-type microcapsule-suspension fluidized bed bioreactor (DMFBB). The void volume in the bioreactor and stability of alginate/chitosan microcapsules were investigated under different flow rates. Cell viability, synthesis and metabolism functions, and expression of metabolizing enzymes at transcriptional levels in an encapsulated hepatocyte line (C3A cells) were determined. The void volume was significantly less in the novel bioreactor than in the conventional FBB. In addition, the microcapsules were less damaged in the DMFBB during the fluidization process as reflected by the results for microcapsule retention rates, swelling, and breakage. Encapsulated C3A cells exhibited greater viability and CYP1A2 and CYP3A4 activity in the DMFBB than in the FBB, although the increases in albumin and urea synthesis were less prominent. The transcription levels of several CYP450-related genes and an albumin-related gene were dramatically greater in cells in the DMFBB than in those in the FBB. Taken together, our results suggest that the DMFBB is a promising alternative for the design of a bioartificial liver system based on a fluidized bed bioreactor with encapsulated hepatocytes for treating patients with acute hepatic failure or other severe liver diseases. PMID:26840840

  10. Proceedings of the Sixth International Conference on Fluidized Bed Combustion. Volume 1. Plenary sessions

    SciTech Connect

    1980-08-01

    The Sixth International Conference on Fluidized Bed Combustion was held at the Atlanta Hilton, Atlanta, Georgia, April 9-11, 1980. The papers in this volume involved presentation of the research and development programs of the US (US DOE, TVA, EPRI and US EPA), United Kingdom, Federal Republic of Germany and the People's Republic of China. Eight papers from Vol. 1 (Plenary Sessions) of the proceedings have been entered individually into EDB and ERA. (LTN)

  11. A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems.

    PubMed

    Lu, Juan; Zhang, Xiaoqian; Li, Jianzhou; Yu, Liang; Chen, Ermei; Zhu, Danhua; Zhang, Yimin; Li, LanJuan

    2016-01-01

    A fluidized bed bioreactor containing encapsulated hepatocytes may be a valuable alternative to a hollow fiber bioreactor for achieving the improved mass transfer and scale-up potential necessary for clinical use. However, a conventional fluidized bed bioreactor (FBB) operating under high perfusion velocity is incapable of providing the desired performance due to the resulting damage to cell-containing microcapsules and large void volume. In this study, we developed a novel diversion-type microcapsule-suspension fluidized bed bioreactor (DMFBB). The void volume in the bioreactor and stability of alginate/chitosan microcapsules were investigated under different flow rates. Cell viability, synthesis and metabolism functions, and expression of metabolizing enzymes at transcriptional levels in an encapsulated hepatocyte line (C3A cells) were determined. The void volume was significantly less in the novel bioreactor than in the conventional FBB. In addition, the microcapsules were less damaged in the DMFBB during the fluidization process as reflected by the results for microcapsule retention rates, swelling, and breakage. Encapsulated C3A cells exhibited greater viability and CYP1A2 and CYP3A4 activity in the DMFBB than in the FBB, although the increases in albumin and urea synthesis were less prominent. The transcription levels of several CYP450-related genes and an albumin-related gene were dramatically greater in cells in the DMFBB than in those in the FBB. Taken together, our results suggest that the DMFBB is a promising alternative for the design of a bioartificial liver system based on a fluidized bed bioreactor with encapsulated hepatocytes for treating patients with acute hepatic failure or other severe liver diseases.

  12. Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors

    SciTech Connect

    Gamwo, I.K.; Miller, A.; Gidaspow, D.

    1992-04-01

    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Spectral analysis of CFB data obtained at Illinois Institute of Technology shows that the frequencies of pressure oscillations are less than 0.1 Hertz and that they increase with solids volume fraction to the usual value of one Hertz obtained in bubbling beds. These data are consistent with the kinetic theory interpretation of density wave propagation.

  13. Pilot plant testing of IGT`s two-stage fluidized-bed/cyclonic agglomerating combustor

    SciTech Connect

    Rehmat, A.; Mensinger, M.C.; Richardson, T.L.

    1993-12-31

    The Institute of Gas Technology (IGT) is conducting a multi-year experimental program to develop and test, through pilot-scale operation, IGT`s two-stage fluidized-bed/cyclonic agglomerating combustor (AGGCOM). The AGGCOM process is based on combining the fluidized-bed agglomeration and gasification technology with the cyclonic combustion technology, both of which have been developed at IGT over many years. AGGCOM is a unique and extremely flexible combustor that can operate over a wide range of conditions in the fluidized-bed first stage from low temperature (desorption) to high temperature (agglomeration), including gasification of high-energy-content wastes. The ACCCOM combustor can easily and efficiently destroy solid, liquid, and gaseous organic wastes, while isolating solid inorganic contaminants within an essentially non-leachable glassy matrix, suitable for disposal in ordinary landfills. Fines elutriated from the first stage are captured by a high-efficiency cyclone and returned to the fluidized bed for ultimate incorporation into the agglomerates. Intense mixing in the second-stage cyclonic combustor ensures high destruction and removal efficiencies (DRE) for organic compounds that may be present in the feed material. This paper presents an overview of the experimental development of the AGGCOM process and progress made to date in designing, constructing, and operating the 6-ton/day AGGCOM pilot plant. Results of the bench-scale tests conducted to determine the operating conditions necessary to agglomerate a soil were presented at the 1991 Incineration Conference. On-site construction of the AGGCOM pilot plant was initiated in August 1992 and completed at the end of March 1993, with shakedown testing following immediately thereafter. The initial tests in the AGGCOM pilot plant will focus on the integrated operation of both stages of the combustor and will be conducted with ``clean`` topsoil.

  14. Surface Modification of Polymer Powders by a Far Cold Remote Nitrogen Plasma in Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Alfaro-López, H. M.; Aiche, Lynda.; Vergnes, Hugues.; Despax, Bernard.; Caussat, Brigitte.; Caquineau, Hubert.

    In this work, nitrogen was grafted on the surface of polyethylene powders in a fluidized bed coupled to a nitrogen microwave post-discharge, under low pressure (10Torr) and low temperature (<90°C). The influences of treatment-duration (1 to 9 h) and nitrogen flow-rate on the XPS (X-ray Photoelectron Spectroscopy) N/C atomic ratio and on the powder wettability have been studied

  15. Analysis of gas/particles flow in the riser of a circulating fluidized bed

    SciTech Connect

    Arastoopour, H.; Benyahia, S.

    1999-07-01

    Computational fluid dynamics (CFD) packages (CFX and Fluent) governing equations were modified using kinetic theory for cohesive and non-cohesive particles of different sizes, and used to simulate 2-dimensional and 3-dimensional transient gas/particle flow behavior using FCC particles in the riser section of a circulating fluidized bed. The calculated solid flux velocity and pressure drop agreed reasonably well with the experimental data obtained using laser doppler anemometer and large-scale experiments.

  16. Incineration of contaminated organic solvents in a fluidized-bed calciner

    SciTech Connect

    Schindler, R.E.

    1980-01-01

    The reprocessing of expended reactor fuels at the Idaho Chemical Processing Plant (ICPP) generates contaminated organic solvents. An evaluation of potential management alternatives shows that several are suitable for management of contaminated solvents containing tri-butyl phosphate (TBP): the solvent could be burned in a commercially-available burner which absorbs the phosphorus on a fluidized-bed of limestone leaving a solid product for burial; the solvent could be burned in a small fluidized-bed calciner which solidifies non-radioactive feed by in-bed combustion of the contaminated solvent. The fluidized-bed absorbs the phosphate forming a solid product for burial; the solvents could be solidified with a gel or sorbant for burial if the reprocessing system were modified to reduce the solvent volume; and the contaminated solvent could be burned in an existing fluidized-bed calciner designed for solidifying high-level aqueous wastes. Burning the solvent in the existing calciner was selected for process verification because it provides an existing burner, off-gas system, and solids transfer and storage system. No additional wastes are generated. A set of four pilot-plant tests verified the absence of adverse effects from the phosphorus in the fuel when calcining simulated ICPP aqueous wastes. Essentially all of the phosphorus remained in the calcined solids with only a neglegible quantity remaining in the scrubbed off-gas. Combustion efficiency was high (93 to 96%). There were no observable adverse effects on solids in the scrubbing system, corrosion rates, or solids flowability (for retrieval). Conclusions of general applicability are: alternative technologies are available for disposal of contaminated solvents, and the use of an existing fuel-using facility, e.g., calciner or incinerator - designed for contaminated wastes will usually be cost effective.

  17. Fluidized bed drying characteristics and modeling of ginger ( zingiber officinale) slices

    NASA Astrophysics Data System (ADS)

    Parlak, Nezaket

    2015-08-01

    In this study fluidized bed drying characteristics of ginger have been investigated. The effects of the fluidizing air temperature, velocity, humidity and bed height on the drying performance of ginger slices have been found. The experimental moisture loss data of ginger slices has been fitted to the eight thin layer drying models. Two-term model drying model has shown a better fit to the experimental data with R2 of 0.998 as compared to others.

  18. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Andy Wu; John T. Riley

    2005-07-30

    This purpose of this report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period April 1, 2005 through June 30, 2005. The following tasks have been completed. First, the new Combustion Laboratory was occupied on June 15, 2005, and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building is in the final painting stage. Second, the fabrication and manufacturing contract for the CFBC Facility was awarded to Sterling Boiler & Mechanical, Inc. of Evansville, Indiana. Sterling is manufacturing the assembly and component parts of the CFBC system. The erection of the CFBC system is expected to start September 1, 2005. Third, mercury emissions from the cofiring of coal and chicken waste was studied experimentally in the laboratory-scale simulated fluidized-bed combustion facility. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described.

  19. Effect of dense phase of fluidized bed pyrolyzer on the devolatilization behavior of coal

    SciTech Connect

    Li Haibin; Chen Yong; Wang Yang

    1998-12-31

    Pyrolysis of coal in fluidized beds were investigated by many researchers. The results of both experiments and model simulations were published. However, there are deviations between the results of different researchers; one of the most important reasons is that the designated features of there experimental devices are different. For example, different freeboard temperature or height will lead to different product compositions. In this paper, the effect of dense phase of fluidized bed on product distribution is discussed when the effect of freeboard is minimized. Shenmu coal ({minus}45 + 80 mesh) was pyrolyzed in a special designed fluidized bed reactor with I.D. of 48mm and a cone-shaped distributor. The temperature of dense phase and freeboard can be controlled respectively. The relationship between gas phase product yield and dense phase temperature was obtained. The results show that the yields of H{sub 2}, CO, CH{sub 4} and C{sub 2}H{sub 4} increase dramatically with increasing dense phase temperature. However, liquid yield reaches the maximum in the dense phase temperature range of 600--650 C. By comparing with the results of former researchers, it can be seen that the volatile can undergo serious secondary reactions when the freeboard temperature is high, even when the residence time is very short. The results of this paper are believed to represent the more accurate trend of the effect of bed temperature on gas phase product yield because the vapor phase secondary reactions were minimized in this experiment.

  20. Erosion of heat exchanger tubes in fluidized beds. Annual report, 1990

    SciTech Connect

    Johnson, E.K.; Flemmer, R.L.C.

    1991-01-01

    This final report describes the activities of the 3-year project entitled ``Erosion of Heat Exchanger Tubes In Fluidized Beds.`` which was completed at the end of 1990. Project accomplishments include the collection of a substantial body of wear data In a 24in. {times} 24in. fluidized bed, comparative wear results In a 6in. {times} 6in. fluidized bed, the development of a dragometer and the collection of a comprehensive set of drag force data in the 24in. {times} 24in. bed, Fast Fourier Transform (FFT) analysis of bubble probe data to establish dominant bubble frequencies in the 24in. {times} 24in. bed, the use of a heat flux gauge for measurement of heat transfer coefficients in the 24in. {times} 24in. bed and the modeling of the tube wear in the 24in. {times} 24in. bed. Analysis of the wear data from the 24in. square bed indicates that tube wear increases with increase in superficial velocity, and with increase in tube height. The latter effect is a result of the tubes higher up in the bed seeing greater movement of dense phase than tubes lower down In the bed. In addition, tube wear was found to decrease with increase in particle size, for constant superficial velocity. Three models of tube wear were formulated and provided acceptable prediction of wear when compared with the experimental data.

  1. Batch separation of shredded bulky waste by gas-solid fluidized bed at laboratory scale.

    PubMed

    Sekito, Tomoo; Tanaka, Nobutoshi; Matsuto, Toshihiko

    2006-01-01

    A gas-solid fluidized bed separator using various bed materials was used to separate shredded municipal bulky waste (SBW). Using 290 microm glass beads as the bed material, the apparent density of the fluidized bed was 1.5 g/cm(3) and the SBW could be separated into combustibles such as wood, paper and plastics and incombustibles such as metals and glass. The overall efficiency (Newton's efficiency) of the separation was calculated to be 0.93. In order to obtain high efficiency, the superficial velocity must be adjusted so that the fluidized bed is agitated moderately and at the same time there is no weak fluidized region. Using a mixture of particles of nylon shot and 68 microm glass beads, the apparent density of the fluidized mixture bed could be varied between 0.63 and 0.99 g/cm(3) by changing the mixing ratio of the two materials. In the case of a mixing ratio of 20% for glass beads, an apparent density of 0.65 g/cm(3) was produced, in which wood and paper components were recovered while plastics remained in the bed to give a final overall efficiency of 0.88.

  2. Experimental and computational studies of hydrodynamics in three-phase and two-phase fluidized beds

    SciTech Connect

    Bahary, M.

    1994-12-01

    The objective of the present study was to investigate the hydrodynamics of three-phase fluidized beds, their rheology, and experimentally verify a predictive three fluid hydrodynamic model developed at the Illinois Institute of Technology, Chicago. The recent reviews show that there exist no such models in the literature. The IIT hydrodynamic model computes the phase velocities and the volume fractions of gas, liquid, and particulate phases. Model verification involves a comparison of these computed velocities and volume fractions to experimental values. In this thesis, a three fluid model is presented. The input into the model can be particulate viscosities either measured with a Brookfield viscometer or derived using the mathematical techniques of kinetic theory of granular flows pioneered by Savage and others. The computer simulation of a three-phase fluidized bed in an asymmetric mode qualitatively predicts the gas, liquid and solid hold-ups (volume fractions) and flow patterns in the industrially important churn-turbulent (bubbly coalesced) regimes. The computations in a fluidized bed with a symmetric distributor incorrectly showed no bubble coalescence. A combination of X-ray and {gamma}-ray densitometers was used to measure the solids and the liquid volume fractions in a two dimensional bed in the bubble coalesced regime. There is a good agreement between the theory for an asymmetric distributor and the experiments.

  3. Materials performance in the atmospheric fluidized-bed cogeneration air heater experiment

    SciTech Connect

    Natesan, K.; Podolski, W.; Wang, D.Y.; Teats, F.G. ); Gerritsen, W.; Stewart, A.; Robinson, K. )

    1991-02-01

    The Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment (ACAHE) sponsored by the US Department of Energy (DOE) was initiated to assess the performance of various heat-exchanger materials to be used in fluidized-bed combustion air heater systems. Westinghouse Electric Corporation, through subcontracts with Babcock Wilcox, Foster Wheeler, and ABB Combustion Engineering Systems, prepared specifications and hardware for the ACAHE tests. Argonne National Laboratory contracted with Rockwell International to conduct tests in the DOE atmospheric fluidized-bed combustion facility. This report presents an overview of the project, a description of the facility and the test hardware, the test operating conditions, a summary of the operation, and the results of analyzing specimens from several uncooled and cooled probes exposed in the facility. Extensive microstructural analyses of the base alloys, claddings, coatings, and weldments were performed on specimens exposed in several probes for different lengths of time. Alloy penetration data were determined for several of the materials as a function of specimen orientation and the exposure location in the combustor. Finally, the data were compared with earlier laboratory test data, and the long-term performance of candidate materials for air-heater applications was assessed.

  4. High temperature degradation by erosion-corrosion in bubbling fluidized bed combustors

    SciTech Connect

    Hou, Peggy Y.; MacAdam, S.; Niu, Y.; Stringer, J.

    2003-04-22

    Heat-exchanger tubes in fluidized bed combustors (FBCs) often suffer material loss due to combined corrosion and erosion. Most severe damage is believed to be caused by the impact of dense packets of bed material on the lower parts of the tubes. In order to understand this phenomenon, a unique laboratory test rig at Berkeley was designed to simulate the particle hammering interactions between in-bed particles and tubes in bubbling fluidized bed combustors. In this design, a rod shaped specimen is actuated a short distance within a partially fluidized bed. The downward specimen motion is controlled to produce similar frequencies, velocities and impact forces as those experienced by the impacting particle aggregates in practical systems. Room temperature studies have shown that the degradation mechanism is a three-body abrasion process. This paper describes the characteristics of this test rig, reviews results at elevated temperatures and compares them to field experience. At higher temperatures, deposits of the bed material on tube surfaces can act as a protective layer. The deposition depended strongly on the type of bed material, the degree of tube surface oxidation and the tube and bed temperatures. With HCl present in the bed, wastage was increased due to enhanced oxidation and reduced oxide scale adherence.

  5. Volume I: fluidized-bed code documentation, for the period February 28, 1983-March 18, 1983

    SciTech Connect

    Piperopoulou, H.; Finson, M.; Bloomfield, D.

    1983-03-01

    This documentation supersedes the previous documentation of the Fluidized-Bed Gasifier code. Volume I documents a simulation program of a Fluidized-Bed Gasifier (FBG), and Volume II documents a systems model of the FBG. The FBG simulation program is an updated version of the PSI/FLUBED code which is capable of modeling slugging beds and variable bed diameter. In its present form the code is set up to model a Westinghouse commercial scale gasifier. The fluidized bed gasifier model combines the classical bubbling bed description for the transport and mixing processes with PSI-generated models for coal chemistry. At the distributor plate, the bubble composition is that of the inlet gas and the initial bubble size is set by the details of the distributor plate. Bubbles grow by coalescence as they rise. The bubble composition and temperature change with height due to transport to and from the cloud as well as homogeneous reactions within the bubble. The cloud composition also varies with height due to cloud/bubble exchange, cloud/emulsion, exchange, and heterogeneous coal char reactions. The emulsion phase is considered to be well mixed.

  6. ESTABLISHMENT OF AN ENVIRONMENTAL CONTROL TECHNOLOGY LABORATORY WITH A CIRCULATING FLUIDIZED-BED COMBUSTION SYSTEM

    SciTech Connect

    Wei-Ping Pan; Andy Wu; John T. Riley

    2005-04-30

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2005 through March 31, 2005. The following tasks have been completed. First, the renovation of the new Combustion Laboratory is nearly complete, and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building is in the final stages. Second, the fabrication and manufacture of the CFBC Facility is being discussed with a potential contractor. Discussions with potential contactor regarding the availability of materials and current machining capabilities have resulted in the modification of the original designs. The selection of the fabrication contractor for the CFBC Facility is expected during the next quarter. Third, co-firing experiments conducted with coal and chicken waste have been initiated in the laboratory-scale simulated fluidized-bed facility. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

  7. Bed material agglomeration during fluidized bed combustion. Technical progress report, April 1, 1995--June 30, 1995

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Smeenk, J.L.

    1995-07-01

    During this quarter, agglomeration tests were conducted in a laboratory-scale fluidized bed combustor using coal and {open_quotes}model{close_quotes} components which allowed controlled amounts of clays and pyrites to be added during the test. These tests permitted a more direct evaluation of the interaction between iron compounds and aluminosilicates. With additional clay and pyrite (under simulated local reducing conditions found at coal feed locations) large agglomerates formed. The agglomerates were many times larger than those formed with a standard coal feed. When only clay was added to the fuel (no additional pyrite), agglomerates formed but they were much smaller and very friable. These tests support the hypothesis that local reducing conditions promote the interaction of iron in a +2 state and aluminosilicate material in the coal which leads to agglomeration during fluidized bed combustion. Also during this quarter, a deposit which formed in a fluidized bed boiler of a Texas-New Mexico Power Company was analyzed to determine the chemical and mineralogic mechanisms responsible for deposit formation. Mineral phases were determined by x-ray diffraction (XRD). Bulk chemical composition was determined by x-ray fluorescence spectroscopy (XRF). Polished sections of the deposit were made for optical and scanning electron microscopy.

  8. Second-Generation Pressurized Fluidized Bed Combustion: Small gas turbine induustrial plant study

    SciTech Connect

    Shenker, J.; Garland, R.; Horazak, D.; Seifert, F.; Wenglarz, R.

    1992-07-01

    Second-Generation Pressurized Fluidized Bed Combustion (PFBC) plants provide a coal-fired, high-efficiency, combined-cycle system for the generation of electricity and steam. The plants use lime-based sorbents in PFB combustors to meet environmental air standards without back-end gas desulfurization equipment. The second-generation system is an improvement over earlier PFBC concepts because it can achieve gas temperatures of 2100[degrees]F and higher for improved cycle efficiency while maintaining the fluidized beds at 1600[degrees]F for enhanced sulfur capture and minimum alkali release. Second-generation PFBC systems are capable of supplying the electric and steam process needs of industrial plants. The basic second-generation system can be applied in different ways to meet a variety of process steam and electrical requirements. To evaluate the potential of these systems in the industrial market, conceptual designs have been developed for six second-generation PFBC plants. These plants cover a range of electrical outputs from 6.3 to 41.5 MWe and steam flows from 46,067 to 442,337 lb/h. Capital and operating costs have been estimated for these six plants and for equivalent (in size) conventional, coal-fired atmospheric fluidized bed combustion cogeneration plants. Economic analyses were conducted to compare the cost of steam for both the second-generation plants and the conventional plants.

  9. Second-Generation Pressurized Fluidized Bed Combustion: Small gas turbine industrial plant study

    SciTech Connect

    Shenker, J.; Garland, R.; Horazak, D.; Seifert, F.; Wenglarz, R.

    1992-07-01

    Second-Generation Pressurized Fluidized Bed Combustion (PFBC) plants provide a coal-fired, high-efficiency, combined-cycle system for the generation of electricity and steam. The plants use lime-based sorbents in PFB combustors to meet environmental air standards without back-end gas desulfurization equipment. The second-generation system is an improvement over earlier PFBC concepts because it can achieve gas temperatures of 2100{degrees}F and higher for improved cycle efficiency while maintaining the fluidized beds at 1600{degrees}F for enhanced sulfur capture and minimum alkali release. Second-generation PFBC systems are capable of supplying the electric and steam process needs of industrial plants. The basic second-generation system can be applied in different ways to meet a variety of process steam and electrical requirements. To evaluate the potential of these systems in the industrial market, conceptual designs have been developed for six second-generation PFBC plants. These plants cover a range of electrical outputs from 6.3 to 41.5 MWe and steam flows from 46,067 to 442,337 lb/h. Capital and operating costs have been estimated for these six plants and for equivalent (in size) conventional, coal-fired atmospheric fluidized bed combustion cogeneration plants. Economic analyses were conducted to compare the cost of steam for both the second-generation plants and the conventional plants.

  10. Effects of magnetic fields on improving mass transfer in flue gas desulfurization using a fluidized bed

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Gui, Keting; Wang, Xiaobo

    2016-02-01

    The effects of magnetic fields on improving the mass transfer in flue gas desulfurization using a fluidized bed are investigated in the paper. In this research, the magnetically fluidized bed (MFB) is used as the reactor in which ferromagnetic particles are fluidized with simulated flue gas under the influence of an external magnetic field. Lime slurry is continuously sprayed into the reactor. As a consequence, the desulfurization reaction and the slurry drying process take place simultaneously in the MFB. In this paper, the effects of ferromagnetic particles and external magnetic fields on the desulphurization efficiency are studied and compared with that of quartz particles as the fluidized particles. Experimental results show that the ferromagnetic particles not only act as a platform for lime slurry to precipitate on like quartz particles, but also take part in the desulfurization reaction. The results also show that the specific surface area of ferromagnetic particles after reaction is enlarged as the magnetic intensity increases, and the external magnetic field promotes the oxidation of S(IV), improving the mass transfer between sulphur and its sorbent. Hence, the efficiency of desulphurization under the effects of external magnetic fields is higher than that in general fluidized beds.

  11. Pyrolysis of Uinta Basin Oil Sands in fluidized bed and rotary kiln reactors

    SciTech Connect

    Nagpal, S.; Fletcher, J.V.; Hanson, F.V.

    1995-12-31

    A pilot-scale fluidized bed reactor (FBR) was used to pyrolyze the mined and crushed ore from the PR Spring oil sands deposit which is located in the Uinta Basin of Utah. Liquid yields of approximately 80 wt% of the bitumen fed to the reactor were obtained. This compares to 55-70 wt% obtained from smaller laboratory scale fluidized bed reactors and a pilot-scale rotary kiln. The product yields and distributions exhibited no discernable trends with reactor temperature or solids retention time. The liquid products obtained from the pilot-scale fluidized bed reactor were upgraded compared to the bitumen in terms of volatility, viscosity, molecular weight, and metals (Ni and V) content. The nitrogen and sulphur contents of the total liquid products were also reduced relative to the bitumen. A comparison of oil sands pyrolysis yields from a pilot scale FBR and a rotary kiln of the same diameter (15.2 cm) was made. Under similar pyrolysis conditions, the rotary kiln produced a slightly more upgraded product but at lower total liquid yields. Kinetic modeling of the various reactors indicates that the pilot-scale FBR product distributions may be explained using a simplified two-reaction scheme. It is proposed that secondary cracking is suppressed in the large diameter FBR due to elimination of slugging and the superior quality of fluidization in the reactor. More experimental studies with the rotary kiln and an economic evaluation will be required before concluding which reactor is preferred for the thermal recovery process.

  12. Postcombustion Capture of CO2 with CaO in a Circulating Fluidized Bed Carbonator

    NASA Astrophysics Data System (ADS)

    Alonso, M.; Rodriguez, N.; González, B.; Grasa, G.; Murillo, R.; Abanades, J. C.

    There is an emerging postcombustion capture technology that uses CaO to capture CO2 from combustion flue gases in a circulating fluidized bed reactor. This paper summarizes recent work conducted at CSIC to understand and develop this technology. The paper includes experimental results at conditions close to those expected in the real system, carried out in continuous mode in a 30kW test facility made up of two interconnected circulating fluidized bed reactors. In one of the reactors, CO2 is captured from the gas phase by the CaO continuously circulating from a calciner. In the second reactor, the CaCO3 formed in the carbonator is regenerated to CaO and CO2 by calcination. Modeling of the system at process level, at reactor level (in particular the CFB carbonator), and at particle level (decay in capture capability of CaO) is also outlined. The work carried out so far confirms that the carbonator reactors can be designed to attain capture efficiencies between 70-90%, operating at fluid dynamic conditions close to those present in circulating fluidized bed combustors.

  13. Experimental studies on oil palm frond drying using swirling fluidized bed dryer

    NASA Astrophysics Data System (ADS)

    Hamdan, Muhammad; Sabudin, Sulastri; Faizal, Mohd; Raghavan, Vijay R.

    2012-06-01

    Fluidized bed drying has become one of the preferred techniques in drying of agricultural products due to its thorough mixing ability and almost uniform moisture transfer from the product. This paper reports experimental studies on drying characteristics of chopped oil palm frond (OPF) when dried in a swirling fluidized bed dryer (SFBD). Unlike conventional fluidized beds, the SFBD is capable of fluidizing agricultural products which are fibrous and irregular in size and geometry, such as chopped OPF. Experiments were conducted to study the effect of hot air temperature ranging from 50°C to 80°C at a flowrate of 450 m3/hour, for two bed loadings. The OPF which consists of leaves and petiole (petiole) has different initial moisture contents of 57% and 70% respectively and dried to a final moisture content of 15%. Although higher temperatures of hot air result in rapid initial migration of moisture from the chopped OPF, the surface hardening due to shrinkage also becomes faster and hence limits further moisture removal prom the product. The OPF leaves and petiole exhibited different drying curves, suggesting the need for drying them separately unlike the current industrial practice for optimizing the drying process.

  14. Development of the fluidized bed thermal treatment process for treating mixed waste

    SciTech Connect

    Semones, G.B.; Williams, P.M.; Stiefvater, S.P.; Mitchell, D.L.; Roecker, B.D.

    1993-05-01

    A fluidized bed system is being developed at Rocky Flats for the treatment of mixed waste (a mixture of radioactive and chemically hazardous waste). The current program builds on experience gained in the 1970`s and 1980`s in tests with bench-scale, pilot-scale, and demonstration-scale fluidized bed systems. The system operates at low temperatures ({approx} 525--600{degree}C) which eliminates many of the disadvantages associated with high temperature thermal treatment processes. The process has shown the ability to destroy polychlorinated biphenyls (PCB`s) with 99.9999% (``six-nines``) destruction efficiency in tests monitored by the Environmental Protection Agency (EPA). The bed makes use of in situ neutralization of acidic off-gases by incorporating sodium carbonate (Na{sub 2}CO{sub 3}) in the bed media. This eliminates using wet scrubbers to treat the off-gas; these produce a high volume of secondary waste. Once in operation, it is expected that the fluidized bed process will yield up to a 40:1 reduction in the volume of the waste.

  15. Materials performance in the atmospheric fluidized-bed cogeneration air heater experiment

    SciTech Connect

    Natesan, K.; Podolski, W.; Wang, D.Y.; Teats, F.G.; Gerritsen, W.; Stewart, A.; Robinson, K.

    1991-02-01

    The Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment (ACAHE) sponsored by the US Department of Energy (DOE) was initiated to assess the performance of various heat-exchanger materials to be used in fluidized-bed combustion air heater systems. Westinghouse Electric Corporation, through subcontracts with Babcock & Wilcox, Foster Wheeler, and ABB Combustion Engineering Systems, prepared specifications and hardware for the ACAHE tests. Argonne National Laboratory contracted with Rockwell International to conduct tests in the DOE atmospheric fluidized-bed combustion facility. This report presents an overview of the project, a description of the facility and the test hardware, the test operating conditions, a summary of the operation, and the results of analyzing specimens from several uncooled and cooled probes exposed in the facility. Extensive microstructural analyses of the base alloys, claddings, coatings, and weldments were performed on specimens exposed in several probes for different lengths of time. Alloy penetration data were determined for several of the materials as a function of specimen orientation and the exposure location in the combustor. Finally, the data were compared with earlier laboratory test data, and the long-term performance of candidate materials for air-heater applications was assessed.

  16. A computer simulation of hydrodynamics and heat transfer at immersed surfaces in a fluidized bed

    SciTech Connect

    Kodikal, N.J.; Bhavnani, S.H.

    1999-07-01

    A computer simulation of the hydrodynamics and heat transfer processes in a fluidized bed with bubbles propagating from a single jet has been developed. The velocity, volume fraction, and temperature distributions of both phases predicted by the model show satisfactory agreement with the experimental models of Kuipers (1990). An Eulerian-Eulerian approach that incorporates a two-fluid model was utilized. The simulation was developed using a general purpose Computational Fluid Dynamics (CFD) solver; PHOENICS{reg{underscore}sign}. The conservation equations describing the physics of the two-phase nature of the fluidized bed are solved using the finite volume approach. The Interphase-Slip-Algorithm, which is a part of the PHOENICS package, was utilized to ensure numerical stability and convergence of the problem. The unsteady state simulation predicts the hydrodynamics and heat transfer in the fluidized bed. Also predicted, is the formation and propagation of a bubble from a single jet near the immersed surface, as a function of time. The heat transfer coefficients prevailing at the immersed heated wall are calculated. The calculated values of the heat transfer coefficients and simulated hydrodynamics compare well with experimental and numerical data present in literature. Such a simulation technique allows performance evaluation for different bed input parameters, and can evolve into a tool that would help in the optimum design of a fluidized combustion chamber.

  17. Study of the combustion of low rank coal in a fluidized bed

    SciTech Connect

    Glaser, R.; Grimes, R.W.

    1991-09-01

    This report describes the results of preliminary combustion tests performed with Eagle Butte Coal in a bubbling, fluidized-bed combustion system. The system was designed for the combustion of low-rank coals and industrial wastes. The work, as proposed, was aimed at not only the evaluation of co-firing of waste material with coal, but also at developing modifications to first generation bubbling bed designs to improve the combustion performance during co-firing. However, the funding for the work was redirected and the combustion tests were suspended soon after the shakedown testing was completed. Consequently, this report describes the results of the tests completed prior to the redirection of the effort and funding. A total of 33 combustion tests were performed in a 6-inch diameter fluidized-bed combustor. Oxygen concentrations were measured at two points in the system; the vent line and at the interface between the fluid bed and the freeboard. These measurements provided a measure of the amount of conversion of coal within the fluidized bed compared to the conversion in the freeboard region. Typically, 75 to 80% of the conversion occurred within the bed. Several experiments were performed in which special bed internals were placed in the bed. The internals were designed to reduce bubble size in the bed thus increasing the surface area of the bubbles and hence promoting oxygen diffusion into the emulsion phase.

  18. Development of an advanced process for drying fine coal in an inclined fluidized bed

    SciTech Connect

    Boysen, J.E.; Cha, C.Y.; Barbour, F.A.; Turner, T.F.; Kang, T.W.; Berggren, M.H.; Hogsett, R.F.; Jha, M.C.

    1990-02-01

    The objective of this research project was to demonstrate a technically feasible and economically viable process for drying and stabilizing high-moisture subbituminous coal. Controlled thermal drying of coal fines was achieved using the inclined fluidized-bed drying and stabilization process developed by the Western Research Institute. The project scope of work required completion of five tasks: (1) project planning, (2) characterization of two feed coals, (3) bench-scale inclined fluidized-bed drying studies, (4) product characterization and testing, and (5) technical and economic evaluation of the process. High moisture subbituminous coals from AMAX Eagle Butte mine located in the Powder River Basin of Wyoming and from Usibelli Coal Mine, Inc. in Healy, Alaska were tested in a 10-lb/hr bench-scale inclined fluidized-bed. Experimental results show that the dried coal contains less than 1.5% moisture and has a heating value over 11,500 Btu/lb. The coal fines entrainment can be kept below 15 wt % of the feed. The equilibrium moisture of dried coal was less than 50% of feed coal equilibrium moisture. 7 refs., 60 figs., 47 tabs.

  19. MULTIFLUID EULERIAN MODELLING OF DENSE GAS-SOLID FLUIDIZED BED HYDRODYNAMICS: INFLUENCE OF THE DISSIPATION PARAMETERS

    SciTech Connect

    Reuge, N; Cadoret, L.; Pannala, Sreekanth; Syamlal, M; Coufort, C; Caussat, B

    2008-01-01

    Computational fluid dynamic (CFD) models must be thoroughly validated before they can be used with confidence for designing fluidized bed reactors. In this study, validation data were collected from a fluidized bed of (Geldart's group B) alumina particles operated at different gas velocities involving two fluidization hydrodynamic regimes (bubbling and slugging). The bed expansion, height of bed fluctuations, and frequency of fluctuations were measured from a videos of the fluidized bed. The Eulerian-Eulerian two fluid model MFIX was then used to simulate the experiments. Two different models for the particle stresses - Schaeffer (Syamlal et al., (1993), Schaeffer (1987)) and Princeton (Srivastava and Sundaresan (2003)) models - and different values of the restitution coefficient and internal angle of friction were evaluated. 3-D simulations are required for getting quantitative and qualitative agreement with experimental data. The results from the Princeton model are in better agreement with data than from the Schaeffer model. Both free-slip and Johnson-Jackson boundary conditions give nearly identical results. An increase in e from 0.8 to 1 leads to larger bed expansions and lower heights of fluctuations in the bubbling regime whereas it leads to unchanged bed expansion and to a massive reduction in the height of fluctuations in the slugging regime. The angle of internal friction (φ) in the range 10 -40 does not affect the bed expansion, but its reduction significantly reduces the height of fluctuations.

  20. Industrial demonstration plant for the gasification of herb residue by fluidized bed two-stage process.

    PubMed

    Zeng, Xi; Shao, Ruyi; Wang, Fang; Dong, Pengwei; Yu, Jian; Xu, Guangwen

    2016-04-01

    A fluidized bed two-stage gasification process, consisting of a fluidized-bed (FB) pyrolyzer and a transport fluidized bed (TFB) gasifier, has been proposed to gasify biomass for fuel gas production with low tar content. On the basis of our previous fundamental study, an autothermal two-stage gasifier has been designed and built for gasify a kind of Chinese herb residue with a treating capacity of 600 kg/h. The testing data in the operational stable stage of the industrial demonstration plant showed that when keeping the reaction temperatures of pyrolyzer and gasifier respectively at about 700 °C and 850 °C, the heating value of fuel gas can reach 1200 kcal/Nm(3), and the tar content in the produced fuel gas was about 0.4 g/Nm(3). The results from this pilot industrial demonstration plant fully verified the feasibility and technical features of the proposed FB two-stage gasification process.

  1. Upgrading light olefin fuel gas and catalytic reformate in a turbulent fluidized bed catalyst reactor

    SciTech Connect

    Kushnerick, J.D.; Harandi, M.N.; Owen, H.

    1989-05-02

    A fluidized bed catalyst process is described for conversion of C/sub 4/- light olefinic gas feedstock to C/sub 5/+ hydrocarbons and for conversion of C/sub 6/ to C/sub 8/ aromatic feedstock to C/sub 7/ to C/sub 11/ aromatics. It consists of: maintaining a fluidized bed of zeolite catalyst particles in a turbulent reactor bed at a temperature of about 500/sup 0/ to 800/sup 0/F, the catalyst having an apparent particle density of about 0.9 to 1.6 g/cm/sup 3/ and a size range of about 1 to 150 microns, an average catalyst particle size of about 20 to 100 microns containing about 10 to 25 weight percent of fine particles having a particle size less than 32 microns; contacting the feedstocks and passing the feedstocks upwardly through the fluidized catalyst bed under turbulent flow conditions at reaction conditions sufficient to convert at least about 70% of the olefin feedstock and to convert at least 5% of the C/sub 6/ to C/sub 8/ aromatic feedstock; maintaining turbulent fluidized bed conditions through the reactor bed between transition velocity and transport velocity at a superficial fluid velocity of about 0.3 to 2 meters per second; and recovering hydrocarbon product containing C/sub 5/+ hydrocarbons C/sub 7/ to C/sub 11/ aromatic hydrocarbons.

  2. Industrial demonstration plant for the gasification of herb residue by fluidized bed two-stage process.

    PubMed

    Zeng, Xi; Shao, Ruyi; Wang, Fang; Dong, Pengwei; Yu, Jian; Xu, Guangwen

    2016-04-01

    A fluidized bed two-stage gasification process, consisting of a fluidized-bed (FB) pyrolyzer and a transport fluidized bed (TFB) gasifier, has been proposed to gasify biomass for fuel gas production with low tar content. On the basis of our previous fundamental study, an autothermal two-stage gasifier has been designed and built for gasify a kind of Chinese herb residue with a treating capacity of 600 kg/h. The testing data in the operational stable stage of the industrial demonstration plant showed that when keeping the reaction temperatures of pyrolyzer and gasifier respectively at about 700 °C and 850 °C, the heating value of fuel gas can reach 1200 kcal/Nm(3), and the tar content in the produced fuel gas was about 0.4 g/Nm(3). The results from this pilot industrial demonstration plant fully verified the feasibility and technical features of the proposed FB two-stage gasification process. PMID:26849201

  3. Investigation of Gas Solid Fluidized Bed Dynamics with Non-Spherical Particles

    SciTech Connect

    Choudhuri, Ahsan

    2013-06-30

    One of the largest challenges for 21st century is to fulfill global energy demand while also reducing detrimental impacts of energy generation and use on the environment. Gasification is a promising technology to meet the requirement of reduced emissions without compromising performance. Coal gasification is not an incinerating process; rather than burning coal completely a partial combustion takes place in the presence of steam and limited amounts of oxygen. In this controlled environment, a chemical reaction takes place to produce a mixture of clean synthetic gas. Gas-solid fluidized bed is one such type of gasification technology. During gasification, the mixing behavior of solid (coal) and gas and their flow patterns can be very complicated to understand. Many attempts have taken place in laboratory scale to understand bed hydrodynamics with spherical particles though in actual applications with coal, the particles are non-spherical. This issue drove the documented attempt presented here to investigate fluidized bed behavior using different ranges of non-spherical particles, as well as spherical. For this investigation, various parameters are controlled that included particle size, bed height, bed diameter and particle shape. Particles ranged from 355 µm to 1180 µm, bed diameter varied from 2 cm to 7 cm, two fluidized beds with diameters of 3.4 cm and 12.4 cm, for the spherical and non-spherical shaped particles that were taken into consideration. Pressure drop was measured with increasing superficial gas velocity. The velocity required in order to start to fluidize the particle is called the minimum fluidization velocity, which is one of the most important parameters to design and optimize within a gas-solid fluidized bed. This minimum fluidization velocity was monitored during investigation while observing variables factors and their effect on this velocity. From our investigation, it has been found that minimum fluidization velocity is independent of bed

  4. Mercury emissions during cofiring of sub-bituminous coal and biomass (chicken waste, wood, coffee residue, and tobacco stalk) in a laboratory-scale fluidized bed combustor.

    PubMed

    Cao, Yan; Zhou, Hongcang; Fan, Junjie; Zhao, Houyin; Zhou, Tuo; Hack, Pauline; Chan, Chia-Chun; Liou, Jian-Chang; Pan, Wei-Ping

    2008-12-15

    Four types of biomass (chicken waste, wood pellets, coffee residue, and tobacco stalks) were cofired at 30 wt % with a U.S. sub-bituminous coal (Powder River Basin Coal) in a laboratory-scale fluidized bed combustor. A cyclone, followed by a quartz filter, was used for fly ash removal during tests. The temperatures of the cyclone and filter were controlled at 250 and 150 degrees C, respectively. Mercury speciation and emissions during cofiring were investigated using a semicontinuous mercury monitor, which was certified using ASTM standard Ontario Hydra Method. Test results indicated mercury emissions were strongly correlative to the gaseous chlorine concentrations, but not necessarily correlative to the chlorine contents in cofiring fuels. Mercury emissions could be reduced by 35% during firing of sub-bituminous coal using only a quartz filter. Cofiring high-chlorine fuel, such as chicken waste (Cl = 22340 wppm), could largely reduce mercury emissions by over 80%. When low-chlorine biomass, such as wood pellets (Cl = 132 wppm) and coffee residue (Cl = 134 wppm), is cofired, mercury emissions could only be reduced by about 50%. Cofiring tobacco stalks with higher chlorine content (Cl = 4237 wppm) did not significantly reduce mercury emissions. This was also true when limestone was added while cofiring coal and chicken waste because the gaseous chlorine was reduced in the freeboard of the fluidized bed combustor, where the temperature was generally below 650 degrees C without addition of the secondary air. Gaseous speciated mercury in flue gas after a quartz filter indicated the occurrence of about 50% of total gaseous mercury to be the elemental mercury for cofiring chicken waste, but occurrence of above 90% of the elemental mercury for all other cases. Both the higher content of alkali metal oxides or alkali earth metal oxides in tested biomass and the occurrence of temperatures lower than 650 degrees C in the upper part of the fluidized bed combustor seemed to be

  5. Mercury emissions during cofiring of sub-bituminous coal and biomass (chicken waste, wood, coffee residue, and tobacco stalk) in a laboratory-scale fluidized bed combustor.

    PubMed

    Cao, Yan; Zhou, Hongcang; Fan, Junjie; Zhao, Houyin; Zhou, Tuo; Hack, Pauline; Chan, Chia-Chun; Liou, Jian-Chang; Pan, Wei-Ping

    2008-12-15

    Four types of biomass (chicken waste, wood pellets, coffee residue, and tobacco stalks) were cofired at 30 wt % with a U.S. sub-bituminous coal (Powder River Basin Coal) in a laboratory-scale fluidized bed combustor. A cyclone, followed by a quartz filter, was used for fly ash removal during tests. The temperatures of the cyclone and filter were controlled at 250 and 150 degrees C, respectively. Mercury speciation and emissions during cofiring were investigated using a semicontinuous mercury monitor, which was certified using ASTM standard Ontario Hydra Method. Test results indicated mercury emissions were strongly correlative to the gaseous chlorine concentrations, but not necessarily correlative to the chlorine contents in cofiring fuels. Mercury emissions could be reduced by 35% during firing of sub-bituminous coal using only a quartz filter. Cofiring high-chlorine fuel, such as chicken waste (Cl = 22340 wppm), could largely reduce mercury emissions by over 80%. When low-chlorine biomass, such as wood pellets (Cl = 132 wppm) and coffee residue (Cl = 134 wppm), is cofired, mercury emissions could only be reduced by about 50%. Cofiring tobacco stalks with higher chlorine content (Cl = 4237 wppm) did not significantly reduce mercury emissions. This was also true when limestone was added while cofiring coal and chicken waste because the gaseous chlorine was reduced in the freeboard of the fluidized bed combustor, where the temperature was generally below 650 degrees C without addition of the secondary air. Gaseous speciated mercury in flue gas after a quartz filter indicated the occurrence of about 50% of total gaseous mercury to be the elemental mercury for cofiring chicken waste, but occurrence of above 90% of the elemental mercury for all other cases. Both the higher content of alkali metal oxides or alkali earth metal oxides in tested biomass and the occurrence of temperatures lower than 650 degrees C in the upper part of the fluidized bed combustor seemed to be

  6. Load maximization of a liquid-solid circulating fluidized bed bioreactor for nitrogen removal from synthetic municipal wastewater.

    PubMed

    Chowdhury, Nabin; Nakhla, George; Zhu, Jesse

    2008-03-01

    A novel liquid-solid circulating fluidized bed bioreactor (LSCFB) configured with anoxic and aerobic columns and lava rock as the biofilm carrier was used to treat synthetic municipal wastewater. Four different empty bed contact times (EBCTs) of 0.82, 0.65, 0.55, and 0.44 h were examined to optimize nutrient removal capability of the system. The LSCFB demonstrated tertiary effluent quality organic and nitrogen removal efficiencies. Effluent characteristics of the LSCFB were soluble biological oxygen demand (SBOD)10 mg l(-1) and total nitrogen (TN)<10 mg l(-1) at organic loading rate (OLR) of 5.3 kg m(-3)d(-1) and nitrogen loading rate of 0.54 kg Nm(-3)d(-1). Remarkably low yields of 0.14, 0.17, 0.19, and 0.21 g VSS g(-1)COD were observed at OLR of 2.6, 3.2, 4.1 and 5.3 kg COD m(-3)d(-1), where increment of biomass growth and detachment rate were also experienced with increasing OLR. However the system demonstrated only 30% phosphorus removal, and mass balances along the anoxic and aerobic columns showed biological phosphorus removal in the system. Organic mass balance showed that approximately 40% of the influent COD was utilized in the anoxic column and the remaining COD was oxidized in the aerobic column. The system is very efficient in nitrification-denitrification, with more than 90% nitrification of ammonium and overall nitrogen removal in the LSCFB was 70+/-11% even at an EBCT of 0.44 h. PMID:18262217

  7. Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Beneficiation

    SciTech Connect

    Roberts, M.J.; Lau, F.S.; Mensinger, M.C. ); Schultz, C.W.; Mehta, R.K.; Lamont, W.E. ); Chiang, S.H.; Venkatadri, R. ); Misra, M. )

    1992-05-01

    The Mineral Resources Institute at the University of Alabama, along with investigators from the University of Pittsburgh and the University of Nevada-Reno, have conducted a research program on the beneficiation, of Eastern oil shales. The objective of the research program was to evaluate and adapt those new and emerging technologies that have the potential to improve the economics of recovering oil from Eastern oil shales. The technologies evaluated in this program can be grouped into three areas: fine grinding kerogen/mineral matter separation, and waste treatment and disposal. Four subtasks were defined in the area of fine grinding. They were as follows: Ultrasonic Grinding, Pressure Cycle Comminution, Stirred Ball Mill Grinding, and Grinding Circuit Optimization. The planned Ultrasonic grinding research was terminated when the company that had contracted to do the research failed. Three technologies for effecting a separation of kerogen from its associated mineral matter were evaluated: column flotation, the air-sparged hydrocyclone, and the LICADO process. Column flotation proved to be the most effective means of making the kerogen/mineral matter separation. No problems are expected in the disposal of oil shale tailings. It is assumed that the tailings will be placed in a sealed pond and the water recycled to the plant as is the normal practice. It may be advantageous, however, to conduct further research on the recovery of metals as by-products and to assess the market for tailings as an ingredient in cement making.

  8. Pressurized fluidized-bed hydroretorting of eastern oil shales. [Estimation of the cost of beneficiating Alabama shale

    SciTech Connect

    Roberts, M.J.; Mensinger, M.C.; Rue, D.M.; Lau, F.S.

    1992-12-01

    This report presents the work performed during the program quarter from September 1, 1992 though November 30, 1992. The Institute of Gas Technology (IGT) is the prime contractor for the program extension to develop the Pressurized Fluidized-Bed Hydroretorting II system technology. Four institutions are working with IGT as subcontractors. Task achievements are discussed for the following active tasks of the program: Subtask 3.7 innovative reactor concept testing; Subtask 3.9 catalytic hydroretorting; Subtask 3.10 autocatalysis in hydroretorting; Subtask 3.11 shale oil upgrading and evaluation; Subtask 4.1.3 stirred ball mill grinding; Subtask 4.1.5 alternative technology evaluation; Subtask 4.1.6 ultrafine size separation; Subtask 4.2.1 column flotation tests; Subtask 4.4 integrated grinding and flotation; Subtask 4.7 economic analysis; Subtask 6.2.2 wastewater treatability; Subtask 6.2.3 waste management facility conceptual design; and Subtask 8 project management and reporting.

  9. Production of ethanol from starch by co-immobilized Zymomonas mobilis -- Glucoamylase in a fluidized-bed reactor

    SciTech Connect

    Sun, M.Y.; Davison, B.H.; Bienkowski, P.R. |; Nghiem, N.P.; Webb, O.

    1997-08-01

    The production of ethanol from starch was studied in a fluidized-bed reactor (FBR) using co-immobilized Zymomonas mobilis and glucoamylase. The FBR was a glass column of 2.54 cm in diameter and 120 cm in length. The Z. mobilis and glucoamylase were co-immobilized within small uniform beads (1.2 to 2.5 mm diameter) of {kappa}-carrageenan. The substrate for ethanol production was a soluble starch. Light steep water was used as the complex nutrient source. The experiments were performed at 35 C and pH range 4.0 to 5.5. The substrate concentrations ranged from 40 to 185 g/L and the feed rates from 10 to 37 mL/min. Under relaxed sterility conditions, the FBR was successfully operated for a period of 22 days, during which no contamination or structural failure of the biocatalyst beads was observed. Maximum volumetric productivity of 38 g ethanol/L-h, which was 76% of the theoretical value, was obtained. Typical ethanol volumetric productivity was in the range of 15 to 20 g/L-h. The average yield was 0.51 g ethanol/g substrate consumed, which was 90% of the theoretical yield. Very low levels of glucose were observed in the reactor, indicating that starch hydrolysis was the rate-limiting step.

  10. Preparation and initial characterization of fluidized bed steam reforming pure-phase standards

    SciTech Connect

    Missimer, D. M.; Rutherford, R. L.

    2013-03-21

    Hanford is investigating the Fluidized Bed Steam Reforming (FBSR) process for their Low Activity Waste. The FBSR process offers a low-temperature continuous method by which liquid waste can be processed with the addition of clay into a sodium aluminosilicate (NAS) waste form. The NAS waste form is mainly comprised of nepheline (NaAlSiO{sub 4}), sodalite (Na{sub 8}[AlSiO{sub 4}]{sub 6}Cl{sub 2}), and nosean (Na{sub 8}[AlSiO{sub 4}]{sub 6}SO{sub 4}). Anions such as perrhenate (ReO{sub 4}{sup -}), pertechnetate (TcO{sub 4}{sup -}), and iodine (I{sup -}) are expected to replace sulfate in the nosean structure and/or chloride in the sodalite mineral structure (atomically bonded inside the aluminosilicate cages that these mineral structures possess). In the FBSR waste form, each of these phases can exist in a variety of solid solutions that differ from the idealized forms observed in single crystals in nature. The lack of understanding of the durability of these stoichiometric or idealized mineral phases complicates the ability to deconvolute the durability of the mixed phase FBSR product since it is a combination of different NAS phases. To better understand the behavior, fabrication and testing of the individual phases of the FBSR product is required. Analytical Development (AD) of the Science and Technology directorate of the Savannah River National Laboratory (SRNL) was requested to prepare the series of phase-pure standards, consisting of nepheline, nosean, and Cl, Re, and I sodalite. Once prepared, X-ray Diffraction (XRD) analyses were used to confirm the products were phase pure. These standards are being used for subsequent characterization studies consisting of the following: single-pass flow-through (SPFT) testing, development of thermodynamic data, and x-ray diffraction (XRD) calibration curves. In addition to the above mentioned phase-pure standards, AD was tasked with fabricating a mixed Tc-Re sodalite.

  11. Leachability of automotive shredder residues burned in a fluidized bed system.

    PubMed

    Lopes, M H; Freire, M; Galhetas, M; Gulyurtlu, I; Cabrita, I

    2009-05-01

    This paper presents the results of the study of a combustible fraction of automotive shredder residues (CASRs) and the corresponding ashes generated by combustion on a fluidized bed pilot with the aim to understand the influence of thermal treatment regarding properties for final disposal, such as landfilling. The chemical composition was evaluated and the leachability behaviour of ashes and CASR was investigated using the three more commonly used tests: the European Standard EN 12457, the US TCLP-EPA 1311 and the Dutch availability test EA NEN 7371. Different results were obtained depending on the specific conditions of the methods employed. It was found that both the CASR and the ashes contained large amounts of toxic metals and other undesirable elements, such as Cl and S. For the CASR, in addition to the leachability of organic matter above the limit set for hazardous materials, the release of heavy metals, either under alkaline and acidic conditions was significant, revealing the serious risks associated to the landfilling practices still being undertaken worldwide. Release of organic matter from ashes was insignificant, but solubility of sulphates increased and chlorides exceed the hazardous limits in the case of fly ashes. Toxic metals were found to leach from the ashes only under acidic conditions, except Pb and Cu which also leached from finer ashes at alkaline pH. Cr also leached from ashes at alkaline pH values. Both the Dutch availability and TCLP revealed much higher leaching intensities than the European Standard due to the acidity of leachants. However, it was found that ashes may be more resistant to acidification because they exhibit much higher acid neutralization capacity (ANC) than the untreated CASR. The study undertaken shows that thermal valorisation of the combustible fraction of ASR may avoid the risks associated with their landfilling; however, care has to be taken with the ashes because they also behave as hazardous residues. Although

  12. Volatile organic compound adsorption in a gas-solid fluidized bed.

    PubMed

    Ng, Y L; Yan, R; Tsen, L T S; Yong, L C; Liu, M; Liang, D T

    2004-01-01

    Fluidization finds many process applications in the areas of catalytic reactions, drying, coating, combustion, gasification and microbial culturing. This work aims to compare the dynamic adsorption characteristics and adsorption rates in a bubbling fluidized bed and a fixed bed at the same gas flow-rate, gas residence time and bed height. Adsorption with 520 ppm methanol and 489 ppm isobutane by the ZSM-5 zeolite of different particle size in the two beds enabled the differentiation of the adsorption characteristics and rates due to bed type, intraparticle mass transfer and adsorbate-adsorbent interaction. Adsorption of isobutane by the more commonly used activated carbon provided the comparison of adsorption between the two adsorbent types. With the same gas residence time of 0.79 seconds in both the bubbling bed and fixed bed of the same bed size of 40 mm diameter and 48 mm height, the experimental results showed a higher rate of adsorption in the bubbling bed as compared to the fixed bed. Intraparticle mass transfer and adsorbent-adsorbate interaction played significant roles in affecting the rate of adsorption, with intraparticle mass transfer being more dominant. The bubbling bed was observed to have a steeper decline in adsorption rate with respect to increasing outlet concentration compared to the fixed bed. The adsorption capacities of zeolite for the adsorbates studied were comparatively similar in both beds; fluidizing, and using smaller particles in the bubbling bed did not increase the adsorption capacity of the ZSM-5 zeolite. The adsorption capacity of activated carbon for isobutane was much higher than the ZSM-5 zeolite for isobutane, although at a lower adsorption rate. Fourier transform infra-red (FTIR) spectroscopy was used as an analytical tool for the quantification of gas concentration. Calibration was done using a series of standards prepared by in situ dilution with nitrogen gas, based on the ideal gas law and relating partial pressure to gas

  13. Simulation of coal gasification in a fluidized bed

    SciTech Connect

    O`Brien, T.J.

    1996-12-31

    In this analysis of coal gasification, a fundamental approach is used where a set of multiphase (Eulerian) fluid dynamic equations, obtained either by a suitable averaging technique (Anderson and Jackson, 1976; Drew, 1971) or the formulations of continuum mechanics (Drew, 1983), is used to describe the conservation of mass, momentum, and energy for three interpenetrating phases. The particles, like the fluidizing gas, are described as interpenetrating continua. Different particle types are treated as distinct phases; in this study, the feed coal and the bed char are represented as separate phases in order to account for their different histories. Constitutive laws account for the exchange of momentum between phases (``drag``) and interphase energy transfer. The stresses within the granular phases are determined by a formulation based on the kinetic theory, characterized by a ``granular temperature``. A computer code, based on this multiphase hydrodynamic model, has been developed at the Morgantown Energy Technology Center for the detailed simulation of gas and particle dynamics in heavily loaded coal conversion processes (Syamlal, Rogers, O`Brien, 1994; Syamlal, 1995). The hydrodynamic simulation showed the reactor operated in a jetting/bubbling mode. A gas jet penetrated a considerable distance into the bed, and then detached as ``bubbles`` which rose to the top of the column. The reaction scheme indicated that the feed coal did not begin to devolatilize until it had traversed this region, because of the time required to heat up. Thus, volatiles were not released in the jetting region of the bed, but higher in the bed. The oxygen fed with the coal, however, reacted immediately with the recirculating hot char. The net effect of the char reaction scheme was to created. CO, which burned in the region where.the jet detached, creating a, fairly stable ``flame``. The tar reaction scheme indicated that none of the tar escaped the bed.

  14. Adapting Data Processing To Compare Model and Experiment Accurately: A Discrete Element Model and Magnetic Resonance Measurements of a 3D Cylindrical Fluidized Bed.

    PubMed

    Boyce, Christopher M; Holland, Daniel J; Scott, Stuart A; Dennis, John S

    2013-12-18

    Discrete element modeling is being used increasingly to simulate flow in fluidized beds. These models require complex measurement techniques to provide validation for the approximations inherent in the model. This paper introduces the idea of modeling the experiment to ensure that the validation is accurate. Specifically, a 3D, cylindrical gas-fluidized bed was simulated using a discrete element model (DEM) for particle motion coupled with computational fluid dynamics (CFD) to describe the flow of gas. The results for time-averaged, axial velocity during bubbling fluidization were compared with those from magnetic resonance (MR) experiments made on the bed. The DEM-CFD data were postprocessed with various methods to produce time-averaged velocity maps for comparison with the MR results, including a method which closely matched the pulse sequence and data processing procedure used in the MR experiments. The DEM-CFD results processed with the MR-type time-averaging closely matched experimental MR results, validating the DEM-CFD model. Analysis of different averaging procedures confirmed that MR time-averages of dynamic systems correspond to particle-weighted averaging, rather than frame-weighted averaging, and also demonstrated that the use of Gaussian slices in MR imaging of dynamic systems is valid. PMID:24478537

  15. Adapting Data Processing To Compare Model and Experiment Accurately: A Discrete Element Model and Magnetic Resonance Measurements of a 3D Cylindrical Fluidized Bed

    PubMed Central

    2013-01-01

    Discrete element modeling is being used increasingly to simulate flow in fluidized beds. These models require complex measurement techniques to provide validation for the approximations inherent in the model. This paper introduces the idea of modeling the experiment to ensure that the validation is accurate. Specifically, a 3D, cylindrical gas-fluidized bed was simulated using a discrete element model (DEM) for particle motion coupled with computational fluid dynamics (CFD) to describe the flow of gas. The results for time-averaged, axial velocity during bubbling fluidization were compared with those from magnetic resonance (MR) experiments made on the bed. The DEM-CFD data were postprocessed with various methods to produce time-averaged velocity maps for comparison with the MR results, including a method which closely matched the pulse sequence and data processing procedure used in the MR experiments. The DEM-CFD results processed with the MR-type time-averaging closely matched experimental MR results, validating the DEM-CFD model. Analysis of different averaging procedures confirmed that MR time-averages of dynamic systems correspond to particle-weighted averaging, rather than frame-weighted averaging, and also demonstrated that the use of Gaussian slices in MR imaging of dynamic systems is valid. PMID:24478537

  16. Implementation of an artificial neural network as a PAT tool for the prediction of temperature distribution within a pharmaceutical fluidized bed granulator.

    PubMed

    Korteby, Yasmine; Mahdi, Yassine; Azizou, Amel; Daoud, Kamel; Regdon, Géza

    2016-06-10

    In this study, a novel in-line measurement technique of the air temperature distribution during a granulation process using a conical fluidized bed was designed and built for the purpose of measuring the temperature under the Process Analytical Technology (PAT) and introduced to predict the establishment of temperature profiles. Three sets of thermocouples were used, placed at different positions covering the whole operating range, connected to data acquisition measurement hardware, allowing an in-line acquisition and recording of temperatures every second. The measurements throughout the fluidized bed were performed in a steady state by spraying a solution of PVP onto a lactose monohydrate powder bed in order to make predictions of the temperature distribution and the hydrodynamics of the bed during the granulation process using Artificial Neural Networks (ANNs) and to establish the different temperature profiles for different process conditions through the precise predicted information by the constructed, trained, validated and tested neural network. The model's testing results showed a strong prediction capacity of the effects of process variables. Indeed, the predicted temperature values obtained with the ANN model were in good agreement with the values measured with in-line reference method and hence the method can have an application as a predictive control tool. PMID:26993961

  17. Alumina coating on dense tungsten powder by fluidized bed metal organic chemical vapour deposition.

    PubMed

    Rodriguez, Philippe; Caussat, Brigitte; Ablitzer, Carine; Iltis, Xavière; Brothier, Meryl

    2011-09-01

    In order to study the feasibility of coating very dense powders by alumina using Fluidized Bed Metal Organic Chemical Vapour Deposition (FB-MOCVD), experiments were performed on a commercial tungsten powder, 75 microm in median volume diameter and 19,300 kg/m3 in grain density. The first part of the work was dedicated to the experimental study of the tungsten powder fluidization using argon as carrier gas at room temperature and at 400 degrees C. Due to the very high density of the tungsten powder, leading to low initial fixed bed heights and low bed expansions, different weights of powder were tested in order to reach satisfactory temperature profiles along the fluidized bed. Then, using argon as a fluidized bed former and aluminium acetylacetonate Al(C5O2H7)3 as a single source precursor, alumina thin films were deposited on tungsten particles at a low temperature range (e.g., 370-420 degrees C) by FB-MOCVD. The influence of the weight of powder, bed temperature and run duration was studied. Characterizations of the obtained samples were performed by various techniques including scanning electron microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS) analyses, Field Emission Gun SEM (FEG-SEM) and Fourier Transform InfraRed (FT-IR) spectroscopy. The different analyses indicated that tungsten particles were uniformly coated by a continuous alumina thin film. The thickness of the film ranged between 25 and 80 nm, depending on the coating conditions. The alumina thin films were amorphous and contained carbon contamination. This latter may correspond to the adsorption of species resulting from incomplete decomposition of the precursor at so low deposition temperature. PMID:22097534

  18. Air-dense medium fluidized bed dry beneficiation of coal: Results of 50 MTPH demonstration plant

    SciTech Connect

    Chen Qingru; Yang Yi; Liang Chuncheng; Tao Xiuxiang; Luo Zhenfu

    1993-12-31

    This paper presents the performance results of the 50 MTPH Coal Dry Beneficiation Demonstration Plant constructed in the Heilongjiang Province of northeastern China. The separating media used in this process consists of an air/dense medium (magnetite, or magnetic pearls, a remnant of coal combustion in power plants) fluidized bed controllable at specific gravities ranging from 1.3 to 2.0. That portion of the feedstock with a specific gravity less than the separating gravity floats to the top of the fluidized bed where it is recovered at one end of the vessel. That portion of the feedstock with a specific gravity higher than the separating gravity sinks and is discharged from the other end of the vessel. The process has separating efficiencies similar to a heavy media vessel or cyclone with the additional advantages of (1) can be utilized in an arid region containing insufficient water supply, (2) results in a dry product requiring no additional dewatering and coal slime treatment, and (3) as result of air flow will remove some surface moisture present in the feedstock. As a result of the magnetite used in the fluidized bed and the subsequent downstream recovery of this magnetite, the current demonstration plant utilizes a 6mm bottom size. The topsize of the feed is a function of the size of the system and the site specific ash liberation requirement. The Demonstration Plant commenced operation in September 1992. The mechanical processes of the system including coal feeding, sizing, gravity separation/beneficiation, and medium recovery, functioned as anticipated from the 10 MTPH pilot plant. Preliminary results with separating gravities in the range of 1.3--2.0 showed a probable error as low as 0.05 with magnetite losses of 0.5 kg/MT of feed.

  19. Performance analysis and pilot plant test results for the Komorany fluidized bed retrofit project

    SciTech Connect

    Snow, G.C.

    1995-12-01

    Detailed heat and mass balance calculations and emission performance projections are presented for an atmospheric fluidized bed boiler bottom retrofit at the 927 MWt (steam output) Komorany power station and district heating plant in the Czech Republic. Each of the ten existing boilers are traveling grate stoker units firing a local, low-rank brown coal. This fuel, considered to be representative of much of the coal deposits in Central Europe, is characterized by an average gross calorific value of 10.5 MJ/kg (4,530 Btu/lb), an average dry basis ash content of 47 %, and a maximum dry basis sulfur content of 1.8 % (3.4 % on a dry, ash free basis). The same fuel supply, together with limestone supplied from the region will be utilized in the retrofit fluidized bed boilers. The primary objectives of this retrofit program are, (1) reduce emissions to a level at or below the new Czech Clean Air Act, and (2) restore plant capacity to the original specification. As a result of the AFBC retrofit and plant upgrade, the particulate matter emissions will be reduced by over 98 percent, SO{sub 2} emissions will be reduced by 88 percent, and NO{sub x} emissions will be reduced by 38 percent compared to the present grate-fired configuration. The decrease in SO{sub 2} emissions resulting from the fluidized bed retrofit was initially predicted based on fuel sulfur content, including the distribution among organic, pyritic, and sulfate forms; the ash alkalinity; and the estimated limestone calcium utilization efficiency. The methodology and the results of this prediction were confirmed and extended by pilot scale combustion trials at a 1.0 MWt (fuel input), variable configuration test facility in France.

  20. Effect of reaction temperature on CO{sub 2} capture using potassium-based solid sorbent in bubbling fluidized-bed reactor

    SciTech Connect

    Seo, Y.; Jo, S.H.; Ryu, C.K.; Yi, C.K.

    2009-06-15

    We investigated the effects of carbonation and regeneration temperature on the CO{sub 2} capture characteristics using SorbKX35, a potassium-based solid sorbent in a bubbling fluidized-bed reactor. A dry sorbent, SorbKX35 consists of K{sub 2}CO{sub 3} for absorption and supporters for mechanical strength. We also measured the physical properties of the sorbent, such as pore size, pore volume, and surface area after carbonation or regeneration, to confirm the extent of the reaction. With H{sub 2}O vapor pretreatment, nearly complete CO{sub 2} removal was initially achieved and maintained for about 10 min within a temperature range of 333.15-363.15 K with 2 s gas residence time. At lower temperature, CO{sub 2} capture was more effective during 1 h of carbonation. From the results of temperature programmed desorption and gas adsorption method (BET), we found that the regeneration of carbonated SorbKX35 was not complete at 473.15 K. The results obtained in this study can be used as basic data for designing and operating a large-scale CO{sub 2} capture process with two fluidized-bed reactors.