Science.gov

Sample records for atmospheric fluidized-bed coal

  1. 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.

  2. 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.

  3. Atmospheric fluidized-bed combustion (AFBC) co-firing of coal and hospital waste. Environmental Assessment

    SciTech Connect

    Not Available

    1993-02-01

    The proposed project involves co-firing of coal and medical waste (including infectious medical waste) in an atmospheric fluidized-bed combustor (AFBC) to safely dispose of medical waste and produce steam for hospital needs. Combustion at the design temperature and residence time (duration) in the AFBC has been proven to render infectious medical waste free of disease producing organisms. The project would be located at the Veterans Affairs (VA) Medical Center in Lebanon, Pennsylvania. The estimated cost of the proposed AFBC facility is nearly $4 million. It would be jointly funded by DOE, Veterans Affairs, and Donlee Technologies, Inc., of York, Pennsylvania, under a cooperative agreement between DOE and Donlee. Under the terms of this agreement, $3.708 million in cost-shared financial assistance would be jointly provided by DOE and the Veterans Affairs (50/50), with $278,000 provided by Donlee. The purposes of the proposed project are to: (1) provide the VA Medical Center and the Good Samaritan Hospital (GSH), also of Lebanon, Pennsylvania, with a solution for disposal of their medical waste; and (2) demonstrate that a new coal-burning technology can safely incinerate infectious medical waste, produce steam to meet hospital needs, and comply with environmental regulations.

  4. Fluidized bed coal combustion reactor

    NASA Technical Reports Server (NTRS)

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

    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.

  5. Pulsed atmospheric fluidized bed combustor apparatus

    DOEpatents

    Mansour, Momtaz N. (Columbia, MD)

    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.

  6. 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.

  7. Fluidized bed selective pyrolysis of coal

    DOEpatents

    Shang, Jer Y. (McLean, VA); Cha, Chang Y. (Golden, CO); Merriam, Norman W. (Laramie, WY)

    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.

  8. Fluidized bed catalytic coal gasification process

    DOEpatents

    Euker, Jr., Charles A. (15163 Dianna La., Houston, TX 77062); Wesselhoft, Robert D. (120 Caldwell, Baytown, TX 77520); Dunkleman, John J. (3704 Autumn La., Baytown, TX 77520); Aquino, Dolores C. (15142 McConn, Webster, TX 77598); Gouker, Toby R. (5413 Rocksprings Dr., LaPorte, TX 77571)

    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.

  9. Modeling of hydrodynamics of large scale atmospheric circulating fluidized bed coal combustors

    SciTech Connect

    Leretaille, P.Y.; Werther, J.; Briand, P.; Montat, D.

    1999-07-01

    A model for evaluation of the hydrodynamics of gas-solid flow in the riser of a circulating fluidized bed coal boiler is proposed. The 3D fields of the gas and solid velocities and of the solid concentration in the riser are estimated from measured data of the vertical pressure profile. The model includes semi-empirical laws developed on the basis of a set of experimental data on six industrial boilers ranging from 12 MWth to 700 MWth. Its relevance for laboratory scale risers was not tested. The estimation of flow of solids near the walls was fulfilled with a special care due to the influence of this flow on heat transfer. For the validation of the model, measurements of solid concentration with guarded capacitance probes were performed in the 250 MWe Stein Industrie-Lurgi type CFB boiler in Gardanne, France. Finally, an attempt to predict the vertical pressure profile on the riser, starting from the operating conditions (and based on an empirical evaluation of the variation of the downward flow of solid from local conditions) is presented and compared to experimental data.

  10. Gas distributor for fluidized bed coal gasifier

    DOEpatents

    Worley, Arthur C. (Mt. Tabor, NJ); Zboray, James A. (Irvine, CA)

    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.

  11. 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.

  12. 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.

  13. Fluidized bed gasification of extracted coal

    DOEpatents

    Aquino, Dolores C. (Houston, TX); DaPrato, Philip L. (Westfield, NJ); Gouker, Toby R. (Baton Rouge, LA); Knoer, Peter (Houston, TX)

    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.

  14. 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.

  15. Fluidized bed injection assembly for coal gasification

    DOEpatents

    Cherish, Peter (Bethel Park, PA); Salvador, Louis A. (Hempfield Township, Westmoreland County, PA)

    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.

  16. 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)

  17. 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.

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

    SciTech Connect

    Not Available

    1988-10-01

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

  19. 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)

  20. Pulsed atmospheric fluidized bed combustor apparatus and process

    DOEpatents

    Mansour, Momtaz N. (Columbia, MD)

    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.

  1. COSTEAM expansion and improvements: design of a coal-fired atmospheric fluidized bed submodel, an oil-fired submodel and input/output improvements

    SciTech Connect

    Reierson, James D.; Rosenberg, Joseph I.; Murphy, Mary B.; Lethi, Minh- Triet

    1980-10-01

    COSTEAM is an interactive computer model designed to estimate the cost of industrial steam produced by various steam plant technologies. At the end of Phase I development, the COSTEAM model included only one submodel to calculate the capital and operating costs of a conventional coal-fired boiler plant with environmental control systems. This report describes the results of Phase II development. Two new submodels are added which calculate costs for steam produced by coal-fired atmospheric fluidized bed boilers and by oil-fired boilers. COSTEAM input/output capabilities are also improved.

  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. 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.

  4. Georgetown University atmospheric fluidized bed boiler cogeneration system

    SciTech Connect

    Podbielski, V.; Shaff, D.P.

    1991-08-01

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

  5. Development and applications of clean coal fluidized bed technology

    SciTech Connect

    Eskin, N.; Hepbasli, A.

    2006-09-15

    Power generation in Europe and elsewhere relies heavily on coal and coal-based fuels as the source of energy. The reliance will increase in the future due to the decreasing stability of price and security of oil supply. In other words, the studies on fluidized bed combustion systems, which is one of the clean coal technologies, will maintain its importance. The main objective of the present study is to introduce the development and the applications of the fluidized bed technology (FBT) and to review the fluidized bed combustion studies conducted in Turkey. The industrial applications of the fluidized bed technology in the country date back to the 1980s. Since then, the number of the fluidized bed boilers has increased. The majority of the installations are in the textile sector. In Turkey, there is also a circulating fluidized bed thermal power plant with a capacity of 2 x 160 MW under construction at Can in Canakkale. It is expected that the FBT has had, or will have, a significant and increasing role in dictating the energy strategies for Turkey.

  6. MONITORING STRATEGIES FOR FLUIDIZED BED COMBUSTION COAL PLANTS

    EPA Science Inventory

    Air and water monitoring strategies for commercial-size Fluidized Bed Combustion (FBC) coal plants are presented. This is one of five reports developing air and water monitoring strategies for advanced coal combustion (FBC), coal conversion (coal gasification and liquefaction), a...

  7. STUDIES OF THE PRESSURIZED FLUIDIZED-BED COAL COMBUSTION PROCESS

    EPA Science Inventory

    The report gives results of studies of the environmental aspects of the pressurized fluidized-bed coal combustion (FBCC) process, using two experimental facilities: a new 218 kg coal/hr miniplant combustor (0.63 MW equivalent), and a 13 kg coal/hr batch combustion unit. Operating...

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

    DOEpatents

    Gall, Robert L. (Morgantown, WV)

    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 combustor and coal gun-tube assembly therefor

    DOEpatents

    Hosek, William S. (Mt. Tabor, NJ); Garruto, Edward J. (Wayne, NJ)

    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.

  10. Mechanisms of coal-water mixture combustion in fluidized beds

    SciTech Connect

    Brown, R.C.

    1990-01-01

    Studies continued on fluidized bed combustion of coal-water-limestone mixtures. The second quarter of FY 1990 was occupied with additional test on calcination and sulfation mechanisms for limestone formulated in coal-water mixtures (CWM). We also began exploring methods for in-situ determination of intrinsic reactivities of sorbent. 7 refs., 4 figs., 2 tabs.

  11. Mechanisms of coal-water mixture combustion in fluidized beds

    SciTech Connect

    Brown, R.C.

    1989-01-01

    The first quarter of FY 1990 was used to correct problems described in the previous progress report and to initiate a series of experiments on calcination and sulfation of coal-water-limestone mixtures (CWLM) in fluidized beds. Results are discussed and compared to the burning of dry coal in a limestone bed. 10 refs., 5 figs.

  12. 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.

  13. Inclined fluidized bed system for drying fine coal

    DOEpatents

    Cha, Chang Y. (Golden, CO); Merriam, Norman W. (Laramie, WY); Boysen, John E. (Laramie, WY)

    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.

  14. 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.

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

    DOEpatents

    Snell, George J. (Fords, NJ); Kydd, Paul H. (Lawrenceville, NJ)

    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.

  16. 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.

  17. 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.

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

    DOEpatents

    Scott, Charles D. (Oak Ridge, TN); Strandberg, Gerald W. (Farragut, TN)

    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.

  19. 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.

  20. Coal-fired CAES system using fluidized bed combustion

    SciTech Connect

    Moskowitz, S.; Schaeffer, R.

    1983-11-01

    Utility requirements for peaking power can be addressed with coal through the unique marriage of the compressed air energy storage and fluidized bed combustion technologies. This paper discusses the results of an evaluation of a pressurized fluidized bed combustion system at air storage pressures from 27 to 68 atm. A conceptual design of the PFBC configuration in a CAES system is presented. Major components of the system are identified as either state-of-the-art or requiring further R and D. The performance of the compressed air energy storage system with an efficiency of 83.4% (based on coal input energy) is presented. The effects of recovery of rejected heat are discussed also.

  1. METHOD FOR ANALYZING EMISSIONS FROM ATMOSPHERIC FLUIDIZED-BED COMBUSTOR

    EPA Science Inventory

    The report describes an experimentally developed method to comprehensively sample and analyze an atmospheric-pressure fluidized-bed combustion (FBC) unit. The method is aimed at providing a cost and information effective environmental assessment of FBC units. The report includes ...

  2. Mechanisms of coal-water mixture combustion in fluidized beds

    SciTech Connect

    Brown, R.C.

    1990-09-01

    The goal of this research program was to ascertain the fundamental mechanisms of coal combustion and limestone utilization when firing coal water-limestone mixtures (CWLM) in fluidized beds. Experiments were performed in an 8-inch diameter bubbling fluidized bed combustor. The combustor was equipped for firing wither CWM or dry coal. Experiments were designed to answer questions about combustion efficiency and limestone utilization for CWM compared to dry coal. We observed that coal-water-mixtures generally burn with higher combustion efficiency than crushed coal. Although water vapor released from CWM can react directly with char, this reaction is negligibly slow at FBC temperatures compared to the char-oxygen reaction. A physical, rather than chemical, mechanism appears to active. Our experiments demonstrated that differences in combustion efficiency cannot be attributed to fundamentally different carbon elutriation mechanisms. The fact that CWM burns with higher combustion efficiency than dry coal simply reflects the fact that char-sand agglomerates formed from CWM injected into a fluidized bed are generally larger than dry coal particles fed into a bed. Calcination and sulfation tests showed that CWLM and dry coal have optimum bed temperature for sorbent utilization when burning CWLM is lower than for dry sorbent. Furthermore, the optimal sorbent utilization is higher for CWLM compared to dry sorbent. We excluded the possibility that local reducing or gasification conditions are responsible for higher sulfur retention obtained with CWLM. We conclude that intimate contact of coal and limestone in agglomerates is the primary reason for improved sorbent utilization. 42 refs., 24 figs., 9 tabs.

  3. 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.

  4. Desulfurization of Coal in Fluidized Beds

    NASA Technical Reports Server (NTRS)

    Maddury, R.; Kalvinskas, J.

    1985-01-01

    Experimental dry chemical process for removing sulfur from coal-and thereby reducing harmful sulfur emissions from coal-fired electric powerplants-promises more economical and effective than older wet chemical processes. New process faster, requires smaller amounts of chemical reagents, and produces no liquid effluents, which poses disposal problem.

  5. 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)

  6. Coal-Fired Fluidized Bed Combustion Cogeneration 

    E-print Network

    Thunem, C.; Smith, N.

    1985-01-01

    with cogeneration. All transformers for connection to the plant power bus and the substation is included. The generator ean operate at 4,160 volts or the .substation voltage. The generator should be equipped with metelr ing, instrumentation, and controls...: Stanley Consultanta Kotea: (I) eao. 1 - Induotr1aI Plant (2) Ceo. 2. - Induotr1al Plant (3) Ceo. 3 - Induotr1al Plant Generation/Condensing System Description Two coal-fired cogeneration methods are investigated - a noncondensing turbine (case 1...

  7. 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)

  8. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    SciTech Connect

    Not Available

    1992-02-01

    The report summarizes unit operating experience and test program progress for 1989 on Colorado-Ute Electric Association's Nucla CFB Demonstration Program. During this period, the objectives of the Nucla Station operating group were to correct problems with refractory durability, resolve primary air fan capacity limitations, complete the high ash and high sulfur coal tests, switch to Salt Creek coal as the operating fuel, and make the unit available for testing without capacity restrictions. Each of these objectives was addressed and accomplished, to varying degrees, except for the completion of the high sulfur coal acceptance tests. (VC)

  9. Experience with atmospheric fluidized bed gasification of switchgrass

    SciTech Connect

    Smeenk, J.; Brown, R.C.

    1998-12-31

    Switchgrass was gasified in a bubbling fluidized bed reactor rated at 800 kW (2.75 MMBtu/hr) thermal input and operating at atmospheric pressure. A combustible gas with higher heating value varying between 4.2--5.9 MJ/Nm{sup 3} (114--160 Btu/scf) was produced. Carbon conversion was approximately 85%. Difficulties in feeding high moisture switchgrass inhibited smooth reactor operation. Several feed systems for switchgrass were tried with varying degrees of success. The results of gasification trials using switchgrass as fuel are described.

  10. ENVIRONMENTAL ASSESSMENT: SOURCE TEST AND EVALUATION REPORT - B AND W/ALLIANCE ATMOSPHERIC FLUIDIZED-BED COMBUSTOR

    EPA Science Inventory

    The report gives results of a comprehensive emission sampling and analysis of a pilot-scale, atmospheric-pressure, coal-fired, fluidized-bed combustor (AFBC). Screening data on organic and inorganic pollutants and indications of biological activity were obtained. The Babcock and ...

  11. 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.

  12. MINIPLANT AND BENCH STUDIES OF PRESSURIZED FLUIDIZED-BED COAL COMBUSTION: FINAL REPORT

    EPA Science Inventory

    The report gives further results of studies on the environmental aspects of the pressurized fluidized-bed coal combustion process, using the 218 kg coal/hr continuous combustion/sorbent regeneration Miniplant (0.63 MW equivalent), and a 13 kg coal/hr bench-scale system.

  13. MINIPLANT STUDIES OF PRESSURIZED FLUIDIZED-BED COAL COMBUSTION: THIRD ANNUAL REPORT

    EPA Science Inventory

    The report presents further results of studies of the environmental aspects of the pressurized fluidized-bed coal combustion process, using the 218 kg coal/hr 'miniplant' continuous-combustion/sorbent-regeneration system (0.63 MW equivalent), and a 13 kg coal/hr bench-scale syste...

  14. Study of factors affecting syngas quality and their interactions in fluidized bed gasification of lignite coal

    E-print Network

    Spiteri, Raymond J.

    of lignite coal Shayan Karimipour a , Regan Gerspacher b , Rajender Gupta a , Raymond J. Spiteri c. " The syngas quality was defined based on conversion, H2/CO, CH4/H2, yield, and gasifier efficiency. " Low coal 2012 Keywords: Lignite coal Gasification Fluidized bed Design of experiments a b s t r a c t A series

  15. Atmospheric fluidized bed combustion for small scale market sectors. Final report

    SciTech Connect

    Ashworth, R.A.; Plessinger, D.A.; Sommer, T.M.; Keener, H.M.; Webner, R.L.

    1997-03-31

    The objective of this project was to demonstrate and promote the commercialization of coal-fired atmospheric fluidized bed combustion (AFBC) systems, with limestone addition for SO{sub 2} emissions control and a baghouse for particulate emissions control. This AFBC system was targeted for small scale industrial-commercial-institutional space and process heat applications. A cost effective and environmentally acceptable AFBC technology in this size range would displace a considerable amount of gas/oil with coal while resulting in significant total cost savings to the owner/operators. In the Proof-of-Concept Phase, a 2.2 x 10{sup 6} Btu/hr unit was installed and successfully operated at Cedar Lane Farms (CLF), a commercial nursery in Ohio. The heat from the fluidized bed was used to heat hot water which was recirculated through greenhouses for cool weather heating. The system was designed to be fully automated with minimal operator attention required. The AFBC system installed at CLF was an improved design that incorporated flyash/sorbent reinjection and an underbed feed system to improve limestone utilization. With these additions it was possible to lower the Ca/S ratio from {approximately} 3.0 to 2.0, and still maintain an SO{sub 2} emissions level of 1.2 lb/10{sup 6} Btu when burning the same high sulfur Ohio coal tested at OARDC.

  16. SUPPORTIVE STUDIES IN FLUIDIZED-BED COMBUSTION

    EPA Science Inventory

    The report gives results of studies supporting the development of atmospheric and pressurized fluidized-bed combustion (FBC) of coal. It includes laboratory and bench-scale studies to provide needed information on combustion optimization, regeneration process development, solid w...

  17. SUPPORT STUDIES IN FLUIDIZED-BED COMBUSTION

    EPA Science Inventory

    The report gives results of working in support of development studies for 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 m...

  18. 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.

  19. Characteristics of Pyrolytic Topping in Fluidized Bed for Different Volatile Coals

    NASA Astrophysics Data System (ADS)

    Xiong, R.; Dong, L.; Xu, G. W.

    Coal is generally combusted or gasified directly to destroy completely the chemical structures, such as aromatic rings containing in volatile coals including bituminite and lignite. Coal topping refers to a process that extracts chemicals with aromatic rings from such volatile coals in advance of combustion or gasification and thereby takes advantage of the value of coal as a kind of chemical structure resource. CFB boiler is the coal utilization facility that can be easily retrofitted to implement coal topping. A critical issue for performing coal topping is the choice of the pyrolytic reactor that can be different types. The present study concerns fluidized bed reactor that has rarely been tested for use in coal topping. Two different types of coals, one being Xiaolongtan (XLT) lignite and the other Shanxi (SX) bituminous, were tested to clarify the yield and composition of pyrolysis liquid and gas under conditions simulating actual operations. The results showed that XLT lignite coals had the maximum tar yield in 823-873K and SX bituminite realized its highest tar yield in 873-923K. Overall, lignite produced lower tar yield than bituminous coal. The pyrolysis gas from lignite coals contained more CO and CO2 and less CH4, H2 and C2+C3 (C2H4, C2H6, C3H6, C3H8) components comparing to that from bituminous coal. TG-FTIR analysis of tars demonstrated that for different coals there are different amounts of typical chemical species. Using coal ash of CFB boiler, instead of quartz sand, as the fluidized particles decreased the yields of both tar and gas for all the tested coals. Besides, pyrolysis in a reaction atmosphere simulating the pyrolysis gas (instead of N2) resulted also in higher production of pyrolysis liquid.

  20. 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.

  1. Influence of sulfation-enhanced salt additives on the corrosion behavior of materials in atmospheric fluidized-bed combustors

    NASA Astrophysics Data System (ADS)

    Chopra, O. K.; Smith, G. W.; Lenc, J. F.; Myles, K. M.; Johnson, I.

    1981-12-01

    Increased utilization of CaO can reduce the amount of limestone required for SO2 retention in atmospheric fluidized-bed combustion (AFBC) systems. A recently developed method of improving the utilization involves treating the limestone with various salts, such as NaCl, CaCl2, or Na2CO3. The influence of these sulfation-enhancement salt additives on corrosion of candidate structural materials for AFBC systems was investigated. Four 100-h and two 1000-h corrosion test runs were conducted in a 152-mm-ID fluidized bed coal combustor. In each run, three air cooled corrosion probes and four uncooled corrosion coupon holders, each with seven specimens were installed at various locations in the fluidized bed and freeboard sections of the combustor. The temperature of the corrosion specimens ranged from 400 to 8500 C. As controls, some of the runs were made without any salt additions. The results indicate that the presence of salt has no effect on the corrosion behavior of the various iron and nickel base alloys that were placed in the freeboard section of the combustor. Although the uncooled alloys within the fluidized bed do undergo oxidation/sulfidation corrosion, the addition of CaCl2 does not further affect the corrosion rate; the addition of NaCl or Na2CO3 increases the corrosion rates for the high nickel alloys, but not for the stainless steels. The observed corrosion rates for all of the alloys from within the fluidized bed containing approximately 2 mol% CaCl2 or Na2CO3 are in good agreement with the rates reported in other similar studies without salt additions. The corrosion data and a metallographic evaluation of the corrosion specimens are presented.

  2. ENVIRONMENTAL ASSESSMENT OF THE FLUIDIZED-BED COMBUSTION OF COAL: METHODOLOGY AND INITIAL RESULTS

    EPA Science Inventory

    The paper discusses a program being conducted by the U.S. Environmental Protection Agency (EPA), aimed at complete environmental assessment (EA) of the fluidized-bed combustion (FBC) of coal. It reviews the EA methodology being developed by EPA: identification of current technolo...

  3. Materials performance in coal-fired fluidized-bed combustion environments

    SciTech Connect

    Natesan, K.

    1993-07-01

    Development of cogeneration systems that involve combustion of coal in a fluidized bed for the generation of electricity and process heat has been in progress for a number of years. This paper addresses some of the key components in these systems, materials requirements/performance, and areas where additional effort is needed to improve the viability of these concepts for electric power generation.

  4. CERAMIC FILTER TESTS AT THE EPA/EXXON PFBC (PRESSURIZED FLUIDIZED BED COAL COMBUSTION) MINIPLANT

    EPA Science Inventory

    The paper describes the performance of the Acurex ceramic bag filter operating at temperatures up to 880C and pressures up to 930 kPa on particulate-laden flue gas from a pressurized fluidized-bed coal combustion (PFBC) unit on a slipstream of gas taken after the second stage cyc...

  5. PRELIMINARY ENVIRONMENTAL ASSESSMENT OF COAL-FIRED FLUIDIZED-BED COMBUSTION SYSTEMS

    EPA Science Inventory

    The report evaluates potential pollutants which could be generated in coal-fired fluidized-bed combustion (FBC) processes. The primary emphasis is on organic compounds, trace elements, inorganic compounds (other than SO2 and Nox), and particulates. Using available bench scale or ...

  6. FIRST TRIALS OF CHEMICALLY ACTIVE FLUIDIZED-BED (CAFB) PILOT PLANT ON COAL

    EPA Science Inventory

    The report gives results of a minirun, carried out on a 0.75-MWe continuous, chemically active fluidized-bed (CAFB) pilot plant during July-August 1976, as part of a program to extend the CAFB process to operate on coal. After 8.5 hours of gasification on Texas lignite and Illino...

  7. Factors affecting cleanup of exhaust gases from a pressurized, fluidized-bed coal combustor

    NASA Technical Reports Server (NTRS)

    Rollbuhler, R. J.; Kobak, J. A.

    1980-01-01

    The cleanup of effluent gases from the fluidized-bed combustion of coal is examined. Testing conditions include the type and feed rate of the coal and the sulfur sorbent, the coal-sorbent ratio, the coal-combustion air ratio, the depth of the reactor fluidizing bed, and the technique used to physically remove fly ash from the reactor effluent gases. Tests reveal that the particulate loading matter in the effluent gases is a function not only of the reactor-bed surface gas velocity, but also of the type of coal being burnt and the time the bed is operating. At least 95 percent of the fly ash particules in the effluent gas are removed by using a gas-solids separator under controlled operating conditions. Gaseous pollutants in the effluent (nitrogen and sulfur oxides) are held within the proposed Federal limits by controlling the reactor operating conditions and the type and quantity of sorbent material.

  8. [Pulsed atmospheric fluidized-bed combustion]. Technical progress report, August--October 1988

    SciTech Connect

    Not Available

    1988-10-01

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

  9. Mild gasification of Usibelli coal in an inclined fluidized-bed reactor

    SciTech Connect

    Merriam, N.W.; Thomas, K.P.; Cha, C.Y.

    1991-02-01

    Results of mild gasification tests of minus 16-mesh Usibelli coal in an inclined fluidized-bed reactor are described in this report. The minus 16-mesh fraction was separated from the coal by screening. The coal was dried to zero moisture content, and about 2 wt % of the volatiles was removed as gas by partial decarboxylation using a 100-lb/hr inclined fluidized-bed dryer. The dried coal was subjected to mild gasification at maximum temperatures of 1050 to 1250{degrees}F (566 to 677{degrees}C) and feed rates of 7.5 lb/hr while using a once-through flow of carbon dioxide as fluidizing gas in a 1-inch-wide, inclined fluidized-bed reactor. Mild gasification of the dried coal resulted in production of 44 to 56 wt % of the dried coal as char, 10 to 13 wt % as liquids, 17 to 28 wt % as gas, and 8 to 21 wt % as fines. The yield of moisture- and ash-free (MAF) liquids varied from 11.4 to 14.2 wt % of the dried coal feed. Chemical analysis was carried out on these products.

  10. A Trial to Separate Formation and Reduction Process During NO Emission in Fluidized Bed Coal Combustion

    NASA Astrophysics Data System (ADS)

    Murakami, T.; Suzuki, Y.; Durrani, A. K.

    A new approach to evaluate NO formation and reduction processes separately in fluidized bed coal combustion has been investigated. Sixteen different coals were burned in a lab-scale bubbling fluidized bed combustor with three different char loadings by changing the inlet oxygen concentration to 20 %, 15 % and 10 %. When O2 consumption rate in the bed becomes zero, N conversion ratio to NO (XNO) indicates a special value without contribution of NO reduction by char particles in the bed. We call it "ultimate NO conversion ratio (XNO*)". This imaginary NO conversion ratio, XNO*, expresses an NO conversion of a coal particle which burns singly in a fluidized bed combustor. Since there are no other char particles in the bed, XNO* should express a coal's original NO emission. XNO* can be determined by an extrapolation of a line, which is determined by a least-squares method, showing the relationship between XNO and O2 consumption rates for each tested coal. By this technique, the contribution of char particles to NO reduction and the original NO emission of the tested coals can be separated from each other.

  11. Mutagenicity and cytotoxicity of coal fly ash from fluidized-bed and conventional combustion.

    PubMed

    Mumford, J L; Lewtas, J

    1982-01-01

    In summary, fly-ash samples from a pressurized fluidized-bed combustion miniplant were found to consist of submicron, irregular particles that were cytotoxic and contained bioavailable mutagens. The fly-ash emission sample from a conventional coal-fired power plant was found to consist of spherical particles that were also cytotoxic but less mutagenic. The FBC fly ash investigated here was collected from an experimental miniplant and should not be considered representative of fly ash that may be obtained in the future from larger commercial-scale FBC plants. Further health and environmental assessment studies of coal fly-ash samples collected at multiple sites, including commercial-scale fluidized-bed and other conventional combustors, are needed to evaluate the potential health effects of coal fly ash from both types of combustion technology. PMID:6761446

  12. Nitrogen oxides, sulfur trioxide, and mercury emissions during oxy-fuel fluidized bed combustion of Victorian brown coal.

    PubMed

    Roy, Bithi; Chen, Luguang; Bhattacharya, Sankar

    2014-12-16

    This study investigates, for the first time, the NOx, N2O, SO3, and Hg emissions from combustion of a Victorian brown coal in a 10 kWth fluidized bed unit under oxy-fuel combustion conditions. Compared to air combustion, lower NOx emissions and higher N2O formation were observed in the oxy-fuel atmosphere. These NOx reduction and N2O formations were further enhanced with steam in the combustion environment. The NOx concentration level in the flue gas was within the permissible limit in coal-fired power plants in Victoria. Therefore, an additional NOx removal system will not be required using this coal. In contrast, both SO3 and gaseous mercury concentrations were considerably higher under oxy-fuel combustion compared to that in the air combustion. Around 83% of total gaseous mercury released was Hg(0), with the rest emitted as Hg(2+). Therefore, to control harmful Hg(0), a mercury removal system may need to be considered to avoid corrosion in the boiler and CO2 separation units during the oxy-fuel fluidized-bed combustion using this coal. PMID:25402169

  13. Operating Experience of a Coal Fired Fluidized Bed at Georgetown University 

    E-print Network

    Lutes, I. G.; Gamble, R. L.

    1980-01-01

    the bed achieves a Coal Flow 9565 lb/hr Limestone Flow 3133 lb/hr temperature of 1200 - l400F, the spreader feeder is Bed Removal Flow 1000 lb/hr put into service and bed temperature is stabilized at Flyash Flow 1308 lb/hr Design Coal Bituminous... at l600F To maximize coal combustion efficiency, flyash with an 8 ft/sec fluidizing velocity. The excellent reinjection from an internal cinder trap in the boil heat transfer characteristic of the fluidized bed er and an external mechanical dust...

  14. Fluidized bed boiler feed system

    DOEpatents

    Jones, Brian C. (Windsor, CT)

    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.

  15. 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.

  16. Capture of toxic metals by vaious sorbents during fluidized bed coal combustion

    SciTech Connect

    Ho, T.C.; Ghebremeskel, A.; Hopper, J.R.

    1995-12-31

    This study investigated the potential of employing suitable sorbents to capture trace metallic substances during fluidized bed coal combustion. The objectives of the study were to demonstrate the capture process, identify effective sorbents, and characterize the capture efficiency. Experiments were carried out in a 25.4 mm (1 ``) quartz fluidized bed coal combustor enclosed in an electric furnace. In an experiment, a coal sample from the DOE Coal Sample Bank or the Illinois Basin Coal Sample Bank was burned in the bed with a sorbent under various combustion conditions and the amount of metal capture by the sorbent was determined. The metals involved in the study were arsenic, cadmium, lead, mercury and selenium, and the sorbents tested included bauxite, zeolite and lime. The combustion conditions examined included bed temperature, particle size, fluidization velocity (percent excess air), and sorbent bed height. In addition to the experimental investigations, potential metal-sorbent reactions were also identified through performing chemical equilibrium analyses based on the minimization of system free energy.

  17. PSNH's Northern Wood power project repowers coal-fired plant with new fluidized-bed combustor

    SciTech Connect

    Peltier, R.

    2007-08-15

    The Northern Wood Power project permanently replaced a 50-MW coal-burning boiler (Unit 5) at Public Service of New Hampshire's Schiller station with a state-of-the-art circulating fluidized bed wood-burning boiler of the same capacity. The project, completed in December 2006, reduced emissions and expanded the local market for low-grade wood. For planning and executing the multiyear, $75 million project at no cost to its ratepayers, PSNH wins Power's 2007 Marmaduke Award for excellence in O & M. The award is named for Marmaduke Surfaceblow, the fictional marine engineer/plant troubleshoot par excellence. 7 figs., 1 tab.

  18. Burn coal cleanly in a fluidized bed - The key is in the controls

    NASA Technical Reports Server (NTRS)

    Kobak, J. A.

    1979-01-01

    The fluidized-bed combustion (FBC) process produces few sulfur emissions, and can burn wood, municipal solid waste as well as every kind of coal available in the U.S. The presurized, coal-burning fluidized-bed reactor at NASA's Lewis Research Center is described, together with a discussion of the operating results. The FBC system at Lewis, having a completely instrumented reactor, is used to test turbine blade alloys for future power plant applications. With the same type of coal and limestone used in the first testing phase covering 136 hours, it was found that all NOx values were below the EPA standard of 0.7 lb/MBtu, whereas the maximum observed level of SO2 was above the EPA standard of 1.3 lb/MBtu, but with the average SO2 level, however, only 0.63 lb/MBtu. Unburned hydrocarbon and CO levels were very low, indicating combustion efficiencies of close to 99% in almost all tests. Testing is now underway using high temperature cyclones and gas turbine to eliminate erosion and corrosion effects which were observed after the initial tests on the turbine and blades.

  19. 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.

  20. 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.

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

    SciTech Connect

    Wells, J.W.; Krishnan, R.P.

    1980-10-01

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

  2. The simulation of influence of different coals on the circulating fluidized bed Boiler's combustion performance

    NASA Astrophysics Data System (ADS)

    Yong, Yumei; Lu, Qinggang

    2003-05-01

    The combustion performance of the boiler largely depends on the coal type. Lots of experimental research shows that different fuels have different combustion characteristics. It is obvious that fuel will change the whole operating performance of Circulating Fluidized Bed Combustion (CFBC). We know even in a pilot-scale running boiler, the measurement of some parameters is difficult and costly. Therefore, we developed the way of simulation to evaluate the combustion performance of Chinese coals in CFB. The simulation results show that, different coals will result in different coal particle diameter and comminution depending on their mineral component and the change will affect the distribution of ash in CFBC system. In a word, the computational results are in accordance with experimental results qualitatively but there are some differences quantitatively.

  3. THE SCALE-UP OF LARGE PRESSURIZED FLUIDIZED BEDS FOR ADVANCED COAL FIRED PROCESSES

    SciTech Connect

    Leon Glicksman; Hesham Younis; Richard Hing-Fung Tan; Michel Louge; Elizabeth Griffith; Vincent Bricout

    1998-04-30

    Pressurized fluidization is a promising new technology for the clean and efficient combustion of coal. Its principle is to operate a coal combustor at high inlet gas velocity to increase the flow of reactants, at an elevated pressure to raise the overall efficiency of the process. Unfortunately, commercialization of large pressurized fluidized beds is inhibited by uncertainties in scaling up units from the current pilot plant levels. In this context, our objective is to conduct a study of the fluid dynamics and solid capture of a large pressurized coal-fired unit. The idea is to employ dimensional similitude to simulate in a cold laboratory model the flow in a Pressurized Circulating Fluid Bed ''Pyrolyzer,'' which is part of a High Performance Power System (HIPPS) developed by Foster Wheeler Development Corporation (FWDC) under the DOE's Combustion 2000 program.

  4. Continuous high pressure lump coal feeder design study. [fluidized bed processors

    NASA Technical Reports Server (NTRS)

    Fields, S. F.

    1977-01-01

    A continuous lump coal dry feeder was developed for a pressurized fluidized bed combustor. The approach was to adapt the commercially available Fuller-Kinyon pump to feed coal against a pressure differential of 100 psi or more. The pump was modified and tests performed at various pressure differentials, with differently pitched screws, various screw rotational speeds, and various seal lengths and configurations. Successful operation of the modified Fuller-Kinyon pump was generally limited to pressure differentials of 60 psi or less. Although the results are not conclusive, test data and observations were made that indicated that higher pressure differentials could be attained by further modifications of the test setup. In particular, it is recommended that further testing be performed after replacing the 40-horsepower pump motor presently in the test setup with a motor having a significantly high power rating (thereby allowing pump operation with longer seals and at higher pressure differentials than those tested so far).

  5. 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.

  6. Co-firing a pressurized fluidized-bed combustion system with coal and refuse derived fuels and/or sludges. Task 16

    SciTech Connect

    DeLallo, M.; Zaharchuk, R.

    1994-01-01

    The co-firing of waste materials with coal in utility scale power plants has emerged as an effective approach to produce energy and manage municipal waste. Leading this approach, the atmospheric fluidized-bed combustor (AFBC) has demonstrated its commercial acceptance in the utility market as a reliable source of power burning a variety of waste and alternative fuels. The fluidized bed, with its stability of combustion, reduces the amount of thermochemical transients and provides for easier process control. The application of pressurized fluidized-bed combustor (PFBC) technology, although relatively new, can provide significant enhancements to the efficient production of electricity while maintaining the waste management benefits of AFBC. A study was undertaken to investigate the technical and economic feasibility of co-firing a PFBC with coal and municipal and industrial wastes. Focus was placed on the production of electricity and the efficient disposal of wastes for application in central power station and distributed locations. Wastes considered for co-firing include municipal solid waste (MSW), tire-derived fuel (TDF), sewage sludge, and industrial de-inking sludge. Issues concerning waste material preparation and feed, PFBC operation, plant emissions, and regulations are addressed. This paper describes the results of this investigation, presents conclusions on the key issues, and provides recommendations for further evaluation.

  7. Attrition of coal ash particles in a fluidized-bed reactor

    SciTech Connect

    Tomeczek, J.; Mocek, P.

    2007-05-15

    Experimental data of ash-particles attrition in a fluidized bed is presented, and also the results of modeling. Five sizes of ash particles (1.02-1.25; 1.25-1.6; 1.6-2.0; 2.0-5.0; 5.0-10.0 mm) produced in an industrial CFB boiler were examined. A new model of mechanical attrition has been proposed which incorporates new parameters: the shape factor of particles and the ratio of the bed height to bed diameter, strongly influencing the rate of bed mass loss. The model describes very well experimental data for coal-ash particles attrition. The attrition-rate coefficient for ash particles was evaluated.

  8. Clearance by the rat of inhaled fly ash from fluidized-bed coal combustion.

    PubMed

    Griffis, L C; Snipes, M B; Brooks, A L

    1981-01-01

    Fly ash from a fluidized-bed coal combustor was neutron-activated and administered to male Fischer 344 rats by a single nose-only inhalation exposure. The activated fly ash contained 46Sc and smaller amounts of other gamma-emitting radionuclides. Whole-body clearance of radioactivity to 127 d was described by an exponential equation, with the long-term component having a biological half-life of 78 d. High-resolution gamma spectra of the lungs were obtained with a Ge(Li) detector and the relative activities of several fly ash constituents were compared. The activities of 152Eu, 134Cs, 54Mn, and 60Co significantly decreased with time relative to those of 46Sc and 59Fe. These results indicate that the clearance of fly ash is similar to that of other relatively insoluble particles and that some elements may have been preferentially dissolved from the fly ash particles in vivo. PMID:7265291

  9. Analysis of atmospheric fluidized bed combustion agglomerates. Final report

    SciTech Connect

    Perkins, D. III; Brekke, D.W.; Karner, F.R.

    1984-04-01

    Chemical and textural studies of AFBC agglomerates have revealed detailed information regarding the mechanisms of agglomeration. The formation of agglomerates in a silica sand bed can be described by a four step process: initial ash coatings of quartz grains; thickening of ash coatings and the formation of nodules; cementation of nodules to each other by a sulfated aluminosilicate matrix; and partial or complete melting of eutectic compositions to produce a sticky glass phase between grains and along fractures. Once agglomeration has begun, large scale solidification and restricted flow within the bed will lead to hot spots, wholesale melting and further agglomeration which ultimately forces a shutdown. Standard operating temperatures during normal AFBC runs come quite close to, or may actually exceed, the minimum temperatures for eutectic melting of the silicate phases in the coal and standard bed materials. The partially melted material may be expected to lead to the formation of dense, sticky areas within the bed, and the formation of hot spots which further exacerbate the problem. Ultimately, large scale bed agglomeration will result. Attempts to eliminate agglomeration by removal of sodium via an ion exchange process have yielded encouraging results. A second approach, used to raise melting temperatures within the bed, has been to use bed materials that may react with low-temperature minerals to produce high-temperature refractory phases such as mullite or other alkali and alkali-earth alumino-silicates.

  10. Atmospheric fluidized bed combustion of municipal solid waste: test program results

    SciTech Connect

    Preuit, L C; Wilson, K B

    1980-05-01

    Air classified municipal solid waste (MSW) was fired in an atmospheric fluidized bed combustor at low excess air to simulate boiler conditions. The 7 ft/sup 2/ combustor at Combustion Power Company's energy laboratory in Menlo Park, CA, incorporates water tubes for heat extraction and recycles elutriated particles to the bed. System operation was stable while firing processed MSW for the duration of a 300-h test. Low excess air, low exhaust gas emissions, and constant bed temperature demonstrated feasibility of steam generation from fluidized bed combustion of MSW. During the 300-h test, combustion efficiency averaged 99%. Excess air was typically 44% while an average bed temperature of 1400/sup 0/F and an average superficial gas velocity of 4.6 fps were maintained. Typical exhaust emission levels were 30 ppM SO/sub 2/, 160 ppM NO/sub x/, 200 ppM CO, and 25 ppM hydrocarbons. No agglomeration of bed material or detrimental change in fluidization properties was experienced. A conceptual design study of a full scale plant to be located at Stanford University was based on process conditions from the 300-h test. The plant would produce 250,000 lb/hr steam at the maximum firing rate of 1000 tons per day (TPD) processed MSW. The average 800 TPD firing rate would utilize approximately 1200 TPD raw MSW from surrounding communities. The Stanford Solid Waste energy Program was aimed at development of a MSW-fired fluidized bed boiler and cogeneration plant to supply most of the energy needs of Stanford University.

  11. COMBUSTION OF OIL SHALE IN FLUIDIZED-BED COMBUSTORS: AN OVERVIEW

    EPA Science Inventory

    The report gives an overview of the combustion of oil shale in fluidized-bed combustors. Oil shale can be combusted directly, or as a supplement to coal fuel, and can function as an SO2 sorbent in atmospheric fluidized-bed combustion (AFBC). Spent shale from retorting processes m...

  12. Reduction of iron ore fines by coal fines in a packed bed and fluidized bed apparatus—A comparative study

    NASA Astrophysics Data System (ADS)

    Haque, R.; Ray, H. S.; Mukherjee, A.

    1993-06-01

    Reduction of iron ore fines by coal fines in packed and fluidized beds has been studied. The investigation includes study of the kinetic aspects of reduction, carbon and sulfur content of the direct reduced iron (DRI) produced, and metallography of the products. For both processes, the kinetic data fit the first-order reaction model. Reduction in a fluidized bed is much faster than in a packed bed system. In both cases, DRI contains a substantial amount of free carbon at the initial stages of reduction. At the later stages of reduction, the carbon present in the DRI is mainly in the combined state. For identical temperatures and particle sizes, reaction in fluidized bed is much faster compared to that in a packed bed. At any particular degree of reduction, sulfur content in DRI samples produced by fluidized bed reduction is always more than that of DRI samples produced by packed bed reduction. Scanning electron microscopy (SEM) micrographs reveal that metallic whiskers formed during reduction in packed beds only. These whiskers become more prominent at higher temperatures and longer times.

  13. Hydrodynamic behavior of a liquid-solid fluidized-bed reactor for the bioconversion of coal particles to liquid products

    SciTech Connect

    Scott, T.C.; Kaufman, E.N.; Cosgrove, J.M.; Asif, M.; Petersen, J.N.

    1993-10-01

    A predictive mathematical model based on particle convection and dispersion is presented for a liquid fluidized bed of coal particles. The numerical representation can follow transient behavior of liquid fluidized beds that contain a defined particle-size distribution. The calculations exhibited excellent agreement when compared to experimental transient pressure-drop data from a column containing particles of Illinois No. 6 bituminous coal in the size range of 20 to 120 {mu}m. In addition, the model was used to simulate the effect of periodic (hourly) liquid velocity step changes on elutriation of small particles from a given particle-size distribution of 34.5 to 75.5 {mu}m. For the situation tested, the calculations indicate that (a) the column does not reach a steady state between velocity changes and (b) that higher initial particle elutriation rates decay to lower values until no more particles elutriate from the column.

  14. Empirical models of emissions and energy efficiencies of coal-fired fluidized bed power plants

    E-print Network

    Gruhl, Jim

    Mass and energy balances of fluidized bed energy technologies are to a significant degree dependent upon the specific design being investigated. It is difficult to make any generally accurate comments. about these balances. ...

  15. Hydrogen-Rich Gas Production by Cogasification of Coal and Biomass in an Intermittent Fluidized Bed

    PubMed Central

    Wang, Li-Qun; Chen, Zhao-Sheng

    2013-01-01

    This paper presents the experimental results of cogasification of coal and biomass in an intermittent fluidized bed reactor, aiming to investigate the influences of operation parameters such as gasification temperature (T), steam to biomass mass ratio (SBMR), and biomass to coal mass ratio (BCMR) on hydrogen-rich (H2-rich) gas production. The results show that H2-rich gas free of N2 dilution is produced and the H2 yield is in the range of 18.25~68.13?g/kg. The increases of T, SBMR, and BCMR are all favorable for promoting the H2 production. Higher temperature contributes to higher CO and H2 contents, as well as H2 yield. The BCMR has a weak influence on gas composition, but the yield and content of H2 increase with BCMR, reaching a peak at the BCMR of 4. The H2 content and yield in the product gas increase with SBMR, whilst the content of CO increases first and then decreases correspondingly. At a typical case, the relative linear sensitivity coefficients of H2 production efficiency to T, SBMR, and BCMR were calculated. The results reveal that the order of the influence of the operation parameters on H2 production efficiency is T > SBMR > BCMR. PMID:24174911

  16. Computerized simulation of the dynamic response of a coal-fired power plant with pressurized fluidized bed

    NASA Astrophysics Data System (ADS)

    Plackmeyer, J.

    1982-07-01

    The simple way of desulfurizing, the efficient combustion of coal, and low carbon monoxide flue gas content of a fluidized bed combustion installation were studied. The dynamic response of a pressurized fluidized bed should also be studied before any construction is started. The physical-mathematical models of all single components were developed and combined in a total computer program. Starting point was the planned pilot plant with gas turbine engine. Various modifications of the purely air cooled plant as well as the extension to a combined cycle with additional steam turbine were considered. Operating cases were simulated: starting up, increasing from partial load to full load and vice versa, shut down and breakdowns. Results show that all operating cases could be brought under control as well as breakdowns. The constructive precautions and correct plant practice are described.

  17. 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.

  18. Release of sulfur and chlorine during cofiring RDF and coal in an internally circulating fluidized bed

    SciTech Connect

    Xiaolin Wei; Yang Wang; Dianfu Liu; Hongzhi Sheng; Wendong Tian; Yunhan Xiao

    2009-03-15

    An internally circulating fluidized bed (ICFB) was applied to investigate the behavior of chlorine and sulfur during cofiring RDF and coal. The pollutant emissions in the flue gas were measured by Fourier transform infrared (FTIR) spectrometry (Gasmet DX-3000). In the tests, the concentrations of the species CO, CO{sub 2}, HCl, and SO{sub 2} were measured online. Results indicated when cofiring RDF and char, due to the higher content of chlorine in RDF, the formation of HCl significantly increases. The concentration of SO{sub 2} is relatively low because alkaline metal in the fuel ash can absorb SO{sub 2}. The concentration of CO emission during firing pure RDF is relatively higher and fluctuates sharply. With the CaO addition, the sulfur absorption by calcium quickly increases, and the desulfurization ratio is bigger than the dechlorination ratio. The chemical equilibrium method is applied to predict the behavior of chlorine. Results show that gaseous HCl emission increases with increasing RDF fraction, and gaseous KCl and NaCl formation might occur. 35 refs., 18 figs., 2 tabs.

  19. Lewis Research Center's coal-fired, pressurized, fluidized-bed reactor test facility

    NASA Technical Reports Server (NTRS)

    Kobak, J. A.; Rollbuhler, R. J.

    1981-01-01

    A 200-kilowatt-thermal, pressurized, fluidized-bed (PFB) reactor, research test facility was designed, constructed, and operated as part of a NASA-funded project to assess and evaluate the effect of PFB hot-gas effluent on aircraft turbine engine materials that might have applications in stationary-power-plant turbogenerators. Some of the techniques and components developed for this PFB system are described. One of the more important items was the development of a two-in-one, gas-solids separator that removed 95+ percent of the solids in 1600 F to 1900 F gases. Another was a coal and sorbent feed and mixing system for injecting the fuel into the pressurized combustor. Also important were the controls and data-acquisition systems that enabled one person to operate the entire facility. The solid, liquid, and gas sub-systems all had problems that were solved over the 2-year operating time of the facility, which culminated in a 400-hour, hot-gas, turbine test.

  20. Application of wasted sea-shell to desulfurizer in fluidized bed coal combustion

    SciTech Connect

    Naruse, Ichiro; Saito, Katsuhiro; Murakami, Takahiro

    1999-07-01

    Almost all wasted seashells consist of CaCo{sub 3}, and are similar to limestone. It would be proposed that the seashell could be applied as a desulfurizer. In this study, desulfurization characteristics of the seashell are fundamentally studied by using a thermobalance and a bubbling fluidized coal combustor with comparing the results obtained by limestone as a reference. Under the constant calcination temperature, the desulfurization efficiency for the seashells attains more than about 70% after the desulfurization period of 30 h. For the limestones, on the other hand, the desulfurization efficiency becomes only 38%. Under practical conditions of fluidized bed coal combustion, the desulfurization efficiency for the seashells also indicates higher value than that for the limestones. The desulfurization efficiency depends on the pore size distribution of CaO rather than its specific surface area. The mean pore size of the calcined seashell is about 10 times as large as that of the calcined limestones. from Scanning Electro-Microscope (SEM) photos of the surface of CaCO{sub 3}, CaO and the sulfurized particles of the seashells the large pores can be observed. In measuring cross-sectional distribution of sulfur inside the particles by using an Energy Dispersed X-ray (EDX) system, the sulfur in the sulfurized particle of limestone is only trapped near the particle surface. For the seashells, whereas, the sulfur is distributed over the whole body of particle. Desulfurization efficiency for the limestone, into which some alkali metal compounds are added, increases with increasing the concentration of alkali metal compounds added. In order of increasing effect the key elemental species to enhance the desulfurization activities are Cl, Na and K. Alkali metal compounds can enhance the desulfurization activities, due to solution of CaO in molten NaCl. This is one of the reasons why the desulfurization efficiency for the seashells improves.

  1. 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.

  2. The study of partitioning of heavy metals during fluidized bed combustion of sewage sludge and coal

    SciTech Connect

    Gulyurtlu, I.; Lopes, M.H.; Abelha, P.; Cabrita, I.; Oliveira, J.F.S.

    2006-06-15

    The behavior of Cd, Cr, Cu, Co, Mn, Ni, Pb, Zn, and Hg during the combustion tests of a dry granular sewage sludge on a fluidized bed combustor pilot (FBC) of about 0.3 MW was evaluated. The emissions of these heavy metals from mono-combustion were compared with those of co-combustion of the sludge with a bituminous coal. The effect of the addition of limestone was also studied in order to retain sulphur compounds and to verify its influence on the retention of heavy metals (HM). Heavy metals were collected and analyzed from different locations of the installation, which included the stack, the two cyclones, and the material removed from the bed. The results showed that the volatility of metals was rather low, resulting in emissions below the legal limits of the new directive on incineration, with the exception of Hg during the mono-combustion tests. The partitioning of metals, except for Hg, appeared to follow that of ashes, amounting to levels above 90% in the bed streams in the mono-combustion case. For co-combustion, there was a lower fixation of HM in the bed ashes, mostly originating essentially from the sewage sludge, ranging between 40% and 80%. It is believed that in this latter case, a slightly higher temperature could have enhanced the volatilization, especially of Cd and Pb. However these metals were then retained in fly ashes captured in the cyclones. In the case of Hg, the volatilisation was complete. The bed ashes were free of Hg and part of Hg was retained in the cyclones and the rest was emitted either with fine ash particles or in gaseous forms. In mono-combustion the Hg emissions from the stack (particles and gas) accounted, for about 50%. This appeared to have significantly decreased in the case of co-combustion, as only about 75% has been emitted, due to the retention effect of cyclone ashes.

  3. Distribution of polycyclic aromatic hydrocarbons in fly ash during coal and residual char combustion in a pressurized fluidized bed

    SciTech Connect

    Hongcang Zhou; Baosheng Jin; Rui Xiao; Zhaoping Zhong; Yaji Huang

    2009-04-15

    To investigate the distribution of polycyclic aromatic hydrocarbons (PAHs) in fly ash, the combustion of coal and residual char was performed in a pressurized spouted fluidized bed. After Soxhlet extraction and Kuderna-Danish (K-D) concentration, the contents of 16 PAHs recommended by the United States Environmental Protection Agency (U.S. EPA) in coal, residual char, and fly ash were analyzed by a high-performance liquid chromatography (HPLC) coupled with fluorescence and diode array detection. The experimental results show that the combustion efficiency is lower and the carbon content in fly ash is higher during coal pressurized combustion, compared to the residual char pressurized combustion at the pressure of 0.3 MPa. Under the same pressure, the PAH amounts in fly ash produced from residual char combustion are lower than that in fly ash produced from coal combustion. The total PAHs in fly ash produced from coal and residual char combustion are dominated by three- and four-ring PAHs. The amounts of PAHs in fly ash produced from residual char combustion increase and then decrease with the increase of pressure in a fluidized bed. 21 refs., 1 fig., 4 tabs.

  4. FLUIDIZED-BED GASIFICATION OF PEAT, LIGNITE, SUBBITUMINOUS, AND PRETREATED BITUMINOUS COAL

    EPA Science Inventory

    The report summarizes and compares results obtained from gasifying four different feedstocks in a pilot-scale fluidized-bed gasifier. Effects of operating variables (e.g., temperature, steam/carbon feed ratio, bed height, and feed rate) on carbon conversion and gas production are...

  5. JV Task 108 - Circulating Fluidized-Bed Combustion and Combustion Testing of Turkish Tufanbeyli Coal

    SciTech Connect

    Douglas Hajicek; Jay Gunderson; Ann Henderson; Stephen Sollom; Joshua Stanislowski

    2007-08-15

    Two combustion tests were performed at the Energy & Environmental Research Center (EERC) using Tufanbeyli coal from Turkey. The tests were performed in a circulating fluidized-bed combustor (CFBC) and a pulverized coal-fired furnace, referred to as the combustion test facility (CTF). One of the goals of the project was to determine the type of furnace best suited to this coal. The coal is high in moisture, ash, and sulfur and has a low heating value. Both the moisture and the sulfur proved problematic for the CTF tests. The fuel had to be dried to less than 37% moisture before it could be pulverized and further dried to about 25% moisture to allow more uniform feeding into the combustor. During some tests, water was injected into the furnace to simulate the level of flue gas moisture had the fuel been fed without drying. A spray dryer was used downstream of the baghouse to remove sufficient sulfur to meet the EERC emission standards permitted by the North Dakota Department of Health. In addition to a test matrix varying excess air, burner swirl, and load, two longer-term tests were performed to evaluate the fouling potential of the coal at two different temperatures. At the lower temperature (1051 C), very little ash was deposited on the probes, but deposition did occur on the walls upstream of the probe bank, forcing an early end to the test after 2 hours and 40 minutes of testing. At the higher temperature (1116 C), ash deposition on the probes was significant, resulting in termination of the test after only 40 minutes. The same coal was burned in the CFBC, but because the CFBC uses a larger size of material, it was able to feed this coal at a higher moisture content (average of 40.1%) compared to the CTF (ranging from 24.2% to 26.9%). Sulfur control was achieved with the addition of limestone to the bed, although the high calcium-to-sulfur rate required to reduce SO{sub 2} emissions resulted in heat loss (through limestone calcination) and additional ash handling. A more efficient downstream sulfur scrubber capable of operation at a much lower Ca/S ratio would result in significantly higher boiler efficiency for this coal. At the operating temperature of a typical CFBC, bed agglomeration and convective pass fouling are not likely to be significant problems with this fuel. Compared to pulverized coal-firing, CFBC technology is clearly the better choice for this fuel. It provides more efficient sulfur capture, lower NO{sub x} emissions, better solids-handling capability, and can utilize a wetter feedstock, requiring less crushing and sizing. The lower operating temperature of CFBC boilers (820 C) reduces the risk of fouling and agglomeration. Care must be taken to minimize heat loss in the system to accommodate the low heating value of the coal.

  6. Steam activation of a bituminous coal in a multistage fluidized bed pilot plant: Operation and simulation model

    SciTech Connect

    Martin-Gullon, I.; Asensio, M.; Marcilla, A.; Font, R.

    1996-11-01

    A hydrodynamic and kinetic model was developed and applied to simulate the experimental data from a three-stage fluidized bed pilot plant with downcomers. This was used to study the activated carbon production from a Spanish bituminous coal by steam gasification. The steam gasification kinetics, considering the influence of inhibitors, were also determined in a thermobalance. With the kinetic equation and the experimental solids residence time distribution of the pilot plant, the model simulates the overall process that takes place in the reactor. The proposed model is able to reproduce the experimental results satisfactorily.

  7. Performance and economics of co-firing a coal/waste slurry in advanced fluidized-bed combustion

    SciTech Connect

    DeLallo, M.R.; Zaharchuk, R.; Reuther, R.B.; Bonk, D.L.

    1996-09-01

    This study`s objective was to investigate co-firing a pressurized fluidized-bed combustor with coal and refuse-derived fuel for the production of electricity and the efficient disposal of waste. Performance evaluation of the pressurized fluidized-bed combustor (PFBC) power plant co-fired with refuse-derived fuel showed only slightly lower overall thermal efficiency than similar sized plants without waste co-firing. Capital costs and costs of electricity are within 4.2 percent and 3.2 percent, respectively, of waste-free operation. The results also indicate that there are no technology barriers to the co-firing of waste materials with coal in a PFBC power plant. The potential to produce cost-competitive electrical power and support environmentally acceptable waste disposal exists with this approach. However, as part of technology development, there remain several design and operational areas requiring data and verification before this concept can realize commercial acceptance. 3 refs., 3 figs., 4 tabs.

  8. SUPPORT STUDIES IN FLUIDIZED-BED COMBUSTION, 1978 ANNUAL REPORT

    EPA Science Inventory

    The report gives results of laboratory- and process-scale EPA studies supporting the national development of atmospheric and pressurized fluidized-bed combustion (PFBC) of coal. Program objectives are: (1) to develop basic information needed to optimize the use of limestone for S...

  9. Numerical analysis of the process of combustion and gasification of the polydisperse coke residue of high-ash coal under pressure in a fluidized bed

    SciTech Connect

    A.Y. Maistrenko; V.P. Patskov; A.I. Topal; T.V. Patskova

    2007-09-15

    A numerical analysis of the process of 'wet' gasification of high-ash coal under pressure in a low-temperature fluidized bed has been performed. The applicability of the previously developed computational model, algorithm, and program for the case under consideration has been noted. The presence of 'hot spots' (short-time local heatings) at different points of the bed has been confirmed.

  10. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    NASA Astrophysics Data System (ADS)

    Sachs, M.; Schmitt, A.; Schmidt, J.; Peukert, W.; Wirth, K.-E.

    2014-05-01

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder without changing the bulk properties. Using the polymers in a SLM process to build single layers of melted material leads to an improvement of the melted layers.

  11. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    SciTech Connect

    Sachs, M. Schmitt, A. Schmidt, J. Peukert, W. Wirth, K-E

    2014-05-15

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder without changing the bulk properties. Using the polymers in a SLM process to build single layers of melted material leads to an improvement of the melted layers.

  12. Does carbon monoxide burn inside a fluidized bed; A new model for the combustion of coal char particles in fluidized beds

    SciTech Connect

    Hayhurst, A.N. )

    1991-05-01

    Beds of silica sand were fluidized by mixtures of C{sub 3}H{sub 8}, CH{sub 4}, or CO with air. Staring from cold the way such a bed behaved before it reached a steady state was observed visually. In addition, high-speed cine films were taken, as well as measurements of the loudness of the noise emitted. These beds behave in a way indicating that such hot gas mixtures at up to 1000{degrees}C do not burn in the interstices between the sand particles. Instead, combustion occurs either above the bed or in the ascending bubbles. Measurements of the diameter (d{sub ig}) of a bubble made immediately prior to ignition confirmed that the ignition temperature (T{sub ig}) of the bubble varies with d{sub ig} {proportional to} exp (E{sub ig}/RT{sub ig}), so that larger bubbles ignite at lower temperatures. It proved possible to generate combustion of these gas mixtures in the particulate phase by adding Pt-coated catalyst pellets. This leads to a new model for the burning of char particles in a fluidized bed. In the model, char is first oxidized to CO with the reaction C{sub s} + 1/20{sup b} {yields} CO occurring mainly inside the pores of each particle. The resulting CO burns either above the bed or in bubbles rising up the bed, but not in the particulate phase. Considerable uncertainties exist as to the correct values of Nusselt and Sherwood numbers, as well as of, e.g., the intrinsic rate constant for the initial production of CO. However, the model is capable of predicting the temperatures observed for char particles burning in fluidized beds. This paper addresses some of the problems of O{sub 2} diffusing inside the pores of a char particle and then reacting to give CO.

  13. Combustion in fluidized beds

    SciTech Connect

    Dry, F.J.; La Nauze, R.D. )

    1990-07-01

    Circulating fluidized-bed (CFB) combustion systems have become popular since the late 1970s, and, given the current level of activity in the area,it is clear that this technology has a stable future in the boiler market. For standard coal combustion applications, competition is fierce with mature pulverized-fuel-based (PF) technology set to maintain a strong profile. CFB systems, however, can be more cost effective than PF systems when emission control is considered, and, as CFB technology matures, it is expected that an ever-increasing proportion of boiler installations will utilize the CFB concept. CFB systems have advantages in the combustion of low-grade fuels such as coal waste and biomass. In competition with conventional bubbling beds, the CFB boiler often demonstrates superior carbon burn-out efficiency. The key to this combustion technique is the hydrodynamic behavior of the fluidized bed. This article begins with a description of the fundamental fluid dynamic behavior of the CFB system. This is followed by an examination of the combustion process in such an environment and a discussion of the current status of the major CFB technologies.

  14. Comprehensive report to Congress: Clean Coal Technology Program: Arvah B. Hopkins circulating fluidized-bed repowering project: A project proposed by: The City of Tallahassee

    SciTech Connect

    Not Available

    1990-10-01

    The project involves the repowering of a 250-megawatt electrical (MWe) natural gas- or oil-fired boiler with a coal-fired atmospheric circulating fluidized-bed (CFB) boiler to provide steam to an existing turbine generator. The boiler will be the largest of its type. After construction and shakedown, the City of Tallahassee (CoT) plant will be operated for 24 months with at least three different eastern coals. Final coal selection will be based on the Fuels Selection Study, which is part of Phase I-A of the project. Cost, financial, and technical data from the CoT CFB will be provided the utility industry for evaluation of a 250-MWe CFB as a commercially viable clean coal alternative. The objective of the Arvah B. Hopkins CFB Repowering Project is to demonstrate an efficient, economical, and environmentally superior method of generating electric power from coal. The work to be performed under the Cooperative Agreement includes the design, construction, and operation of the demonstration plant. 4 figs.

  15. Effect of cofiring coal and biofuel with sewage sludge on alkali problems in a circulating fluidized bed boiler

    SciTech Connect

    K.O. Davidsson; L.-E. Aamand; A.-L. Elled; B. Leckner

    2007-12-15

    Cofiring experiments were performed in a 12 MW circulating fluidized bed boiler. The fuel combinations were biofuel (wood+straw), coal+biofuel, coal+sewage sludge+biofuel, and sewage sludge+biofuel. Limestone or chlorine (PVC) was added in separate experiments. Effects of feed composition on bed ash and fly ash were examined. The composition of flue gas was measured, including on-line measurement of alkali chlorides. Deposits were collected on a probe simulating a superheater tube. It was found that the fuel combination, as well as addition of limestone, has little effect on the alkali fraction in bed ash, while chlorine decreases the alkali fraction in bed ash. Sewage sludge practically eliminates alkali chlorides in flue gas and deposits. Addition of enough limestone to coal and sludge for elimination of the SO{sub 2} emission does not change the effect of chlorine. Chlorine addition increases the alkali chloride in flue gas, but no chlorine was found in the deposits with sewage sludge as a cofuel. Cofiring of coal and biofuel lowers the alkali chloride concentration in the flue gas to about a third compared with that of pure biofuel. This is not affected by addition of lime or chlorine. It is concluded that aluminum compounds in coal and sludge are more important than sulfur to reduce the level of KCl in flue gas and deposits. 24 refs., 8 figs., 7 tabs.

  16. Nucla circulating atmospheric fluidized bed demonstration project. Quarterly technical progress report, October--December 1990

    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.

  17. Determination of flue gas alkali concentrations in fluidized-bed coal combustion by excimer-laser-induced fragmentation fluorescence

    SciTech Connect

    Hartinger, K.T.; Monkhouse, P.B.; Wolfrum, J.; Baumann, H.; Bonn, B.

    1994-12-31

    Gas-phase sodium concentrations were measured for the first time in situ in the flue gas of a fluidized-bed reactor by the excimer-laser-induced fragmentation fluorescence (ELIF) technique. This method involves using ArF-excimer laser light at 193 nm to simultaneously photodissociate the alkali compounds of interest and excite electronically the alkali atoms formed. The resulting fluorescence from Na (3{sup 2}P) atoms can he readily detected at 589 nm. Measured signals were converted to absolute concentrations using a calibration system that monitors alkali compounds under known conditions of temperature, pressure, and composition and rising the same optical setup as at the reactor. Several different coals were investigated under a specific set of reactor conditions at total pressures close to 1 bar. Sodium concentrations ranging from the sub-ppb region to 20 ppb were obtained, and a detection limit for sodium of 0.1 ppb under the present conditions was estimated. Over the course of the reactor program, contrasting concentration histories were observed for the two lignites and the hard coal investigated. In particular, significantly higher sodium concentrations were found for the hard coal, consistent with both the higher chlorine and sodium contents determined in the corresponding coal analysis.

  18. 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.

  19. In Developping a Bench-Scale Circulating Fluidized Bed Combustor to Burn High Ash Brazilian Coal-Dolomites Mixtures

    NASA Astrophysics Data System (ADS)

    Ramírez Behainne, Jhon Jairo; Hory, Rogério Ishikawa; Goldstein, Leonardo; Bernárdez Pécora, Araí Augusta

    This work considers some of the questions in burning high ash Brazilian coal-dolomite mixtures in a bench-scale circulating fluidized bed combustor (CFBC). Experimental tests were performed with the CE4500 coal from Santa Catarina State, in southern Brazil, with a Sauter mean diameter d p =43 ?m. The coal particles were mixed with dolomite particles of d p = 111 ?m and this fuel mixture was fed into the circulating fluidized reactor, previously loaded with quartz sand particles of d p =353 ?m. This inert material was previously heated by the combustion of liquefied petroleum gas up to the ignition temperature of the fuel mixture. The CFBC unit has a 100mm internal diameter riser, 4.0m high, as well as a 62.8mm internal diameter downcomer. The loop has a cyclone, a sampling valve to collect particles and a 62.8mm internal diameter L-valve to recirculate the particles in the loop. A screw feeder with a rotation control system was used to feed the fuel mixture to the reactor. The operational conditions were monitored by pressure taps and thermocouples installed along the loop. A data acquisition system showed the main operational conditions to control. Experimental tests performed put in evidence the problems found during bed operation, with special attention to the solids feed device, to the L-valve operation, to particle size, solids inventory, fluidized gas velocity, fuel mixture and recirculated solids feeding positions.

  20. Functionalization of polymer powders for SLS-processes using an atmospheric plasma jet in a fluidized bed reactor

    NASA Astrophysics Data System (ADS)

    Sachs, Marius; Schmitt, Adeliene; Schmidt, Jochen; Peukert, Wolfgang; Wirth, Karl-Ernst

    2015-05-01

    Recently additive manufacturing processes such as selective laser sintering (SLS) of polymers have gained more importance for industrial applications [1]. Tailor-made modification of polymers is essential in order to make these processes more efficient and to cover the industrial demands. The so far used polymer materials show weak performance regarding the mechanical stability of processed parts. To overcome this limitation, a new route to functionalize the surface of commercially available polymer particles (PA12; PE-HD; PP) using an atmospheric plasma jet in combination with a fluidized bed reactor has been investigated. Consequently, an improvement of adhesion and wettability [2] of the polymer surface without restraining the bulk properties of the powder is achieved. The atmospheric plasma jet process can provide reactive species at moderate temperatures which are suitable for polymer material. The functionalization of the polymer powders improves the quality of the devices build in a SLS-process.

  1. Functionalization of polymer powders for SLS-processes using an atmospheric plasma jet in a fluidized bed reactor

    SciTech Connect

    Sachs, Marius; Schmitt, Adeliene; Schmidt, Jochen; Peukert, Wolfgang; Wirth, Karl-Ernst

    2015-05-22

    Recently additive manufacturing processes such as selective laser sintering (SLS) of polymers have gained more importance for industrial applications [1]. Tailor-made modification of polymers is essential in order to make these processes more efficient and to cover the industrial demands. The so far used polymer materials show weak performance regarding the mechanical stability of processed parts. To overcome this limitation, a new route to functionalize the surface of commercially available polymer particles (PA12; PE-HD; PP) using an atmospheric plasma jet in combination with a fluidized bed reactor has been investigated. Consequently, an improvement of adhesion and wettability [2] of the polymer surface without restraining the bulk properties of the powder is achieved. The atmospheric plasma jet process can provide reactive species at moderate temperatures which are suitable for polymer material. The functionalization of the polymer powders improves the quality of the devices build in a SLS-process.

  2. FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

    SciTech Connect

    Bruce G. Miller; Sharon Falcone Miller; Robert Cooper; Douglas Donovan; John Gaudlip; Matthew Lapinsky; William Serencsits

    2001-01-18

    The Pennsylvania State University, under contract to the U.S. Department of Energy, National Energy Technology Laboratory is performing a feasibility analysis on installing a state-of-the-art circulating fluidized bed boiler and ceramic filter emission control device at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring multiple biofuels and coal-based feedstocks. The objective of the project is being accomplished using a team that includes personnel from Penn State's Energy Institute, Office of Physical Plant, and College of Agricultural Sciences; Foster Wheeler Energy Services, Inc.; Parsons Energy and Chemicals Group, Inc.; and Cofiring Alternatives. During this reporting period, work focused on performing the design of the conceptual fluidized bed system and determining the system economics.

  3. FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

    SciTech Connect

    Bruce G. Miller; Sharon Falcone Miller; Robert Cooper; Douglas Donovan; John Gaudlip; Matthew Lapinsky; William Serencsits; Neil Raskin; Dale Lamke

    2001-07-13

    The Pennsylvania State University, under contract to the U.S. Department of Energy, National Energy Technology Laboratory is performing a feasibility analysis on installing a state-of-the-art circulating fluidized bed boiler and ceramic filter emission control device at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring multiple biofuels and coal-based feedstocks. The objective of the project is being accomplished using a team that includes personnel from Penn State's Energy Institute, Office of Physical Plant, and College of Agricultural Sciences, Foster Wheeler Energy Services, Inc., Parsons Energy and Chemicals Group, Inc., and Cofiring Alternatives. During this reporting period, work focused on completing the biofuel characterization and the design of the conceptual fluidized bed system.

  4. A dynamic simulation model for power plants with atmospheric and pressurized circulating fluidized bed combustion -- Interactions of plant components and design studies

    SciTech Connect

    Glasmacher-Remberg, C.; Fett, F.N.

    1999-07-01

    Power plants with atmospheric or pressurized circulating fluidized bed combustion are complex technical systems. The operation characteristics of these power plants depend on the behavior of the single components and their interactions. The theoretical understanding of power plant processes of this kind as well as the design, the reliability and the practical operation can be enhanced by the application of mathematical models for the complete process. A dynamic simulation model for power plants with atmospheric circulating fluidized bed combustion (ACFBC) and pressurized circulating fluidized bed combustion (PCFBC) consisting of comprehensive submodels for the subsystems gas turbine, circulating fluidized bed combustor and water/steam cycle is presented. Apart from the investigation of the complete power plant, the simulation program enables the analysis of the three mentioned subsystems separately. Each subsystem is described by a set of unsteady-state differential and algebraic equations solved by an implicit Euler-method using a modified Newton-Raphson method. With the aid of the dynamic simulation program for a selected power plant, the effect of changes in plant operation will be examined for full and part load as well as the transient response of the system due to the carried out operation. Emphasis is laid on the characterization of the interactions between the subsystems. The dynamic simulation program can be used for design studies and it is investigated how changes of the plant design influence the operation characteristics of the example plant.

  5. Utilization of blended fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash in geopolymer

    SciTech Connect

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-15

    In this paper, synthesis of geopolymer from fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash was studied in order to effectively utilize both ashes. FBC-fly ash and bottom ash were inter-ground to three different finenesses. The ashes were mixed with as-received PCC-fly ash in various proportions and used as source material for synthesis of geopolymer. Sodium silicate (Na{sub 2}SiO{sub 3}) and 10 M sodium hydroxide (NaOH) solutions at mass ratio of Na{sub 2}SiO{sub 3}/NaOH of 1.5 and curing temperature of 65 deg. C for 48 h were used for making geopolymer. X-ray diffraction (XRD), scanning electron microscopy (SEM), degree of reaction, and thermal gravimetric analysis (TGA) were performed on the geopolymer pastes. Compressive strength was also tested on geopolymer mortars. The results show that high strength geopolymer mortars of 35.0-44.0 MPa can be produced using mixture of ground FBC ash and as-received PCC-fly ash. Fine FBC ash is more reactive and results in higher degree of reaction and higher strength geopolymer as compared to the use of coarser FBC ash. Grinding increases reactivity of ash by means of increasing surface area and the amount of reactive phase of the ash. In addition, the packing effect due to fine particles also contributed to increase in strength of geopolymers.

  6. Utilization of blended fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash in geopolymer.

    PubMed

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-01

    In this paper, synthesis of geopolymer from fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash was studied in order to effectively utilize both ashes. FBC-fly ash and bottom ash were inter-ground to three different finenesses. The ashes were mixed with as-received PCC-fly ash in various proportions and used as source material for synthesis of geopolymer. Sodium silicate (Na(2)SiO(3)) and 10M sodium hydroxide (NaOH) solutions at mass ratio of Na(2)SiO(3)/NaOH of 1.5 and curing temperature of 65 degrees C for 48h were used for making geopolymer. X-ray diffraction (XRD), scanning electron microscopy (SEM), degree of reaction, and thermal gravimetric analysis (TGA) were performed on the geopolymer pastes. Compressive strength was also tested on geopolymer mortars. The results show that high strength geopolymer mortars of 35.0-44.0MPa can be produced using mixture of ground FBC ash and as-received PCC-fly ash. Fine FBC ash is more reactive and results in higher degree of reaction and higher strength geopolymer as compared to the use of coarser FBC ash. Grinding increases reactivity of ash by means of increasing surface area and the amount of reactive phase of the ash. In addition, the packing effect due to fine particles also contributed to increase in strength of geopolymers. PMID:19854038

  7. Co-firing of oil sludge with coal-water slurry in an industrial internal circulating fluidized bed boiler.

    PubMed

    Liu, Jianguo; Jiang, Xiumin; Zhou, Lingsheng; Wang, Hui; Han, Xiangxin

    2009-08-15

    Incineration has been proven to be an alternative for disposal of sludge with its unique characteristics to minimize the volume and recover energy. In this paper, a new fluidized bed (FB) incineration system for treating oil sludge is presented. Co-firing of oil sludge with coal-water slurry (CWS) was investigated in the new incineration system to study combustion characteristics, gaseous pollutant emissions and ash management. The study results show the co-firing of oil sludge with CWS in FB has good operating characteristic. CWS as an auxiliary fuel can flexibly control the dense bed temperatures by adjusting its feeding rate. All emissions met the local environmental requirements. The CO emission was less than 1 ppm or essentially zero; the emissions of SO(2) and NO(x) were 120-220 and 120-160 mg/Nm(3), respectively. The heavy metal analyses of the bottom ash and the fly ash by ICP/AES show that the combustion ashes could be recycled as soil for farming. PMID:19249155

  8. Fluidized bed calciner apparatus

    DOEpatents

    Owen, Thomas J. (West Richland, WA); Klem, Jr., Michael J. (Richland, WA); Cash, Robert J. (Richland, WA)

    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.

  9. Chemical and toxicological characterization of organic constituents in fluidized-bed and pulverized coal combustion: a topical report

    SciTech Connect

    Chess, E.K.; Later, D.W.; Wilson, B.W.; Harris, W.R.; Remsen, J.F.

    1984-04-01

    Coal combustion fly ash from both conventional pulverized coal combustion (PCC) and fluidized-bed combustion (FBC) have been characterized as to their organic constituents and microbial mutagenic activity. The PCC fly ash was collected from a commercial utility generating plant using a low sulfur coal. The FBC fly ash was from a bench-scale developmental unit at the Grand Forks Energy Technology Center. Bulk samples of each fly ash were extracted using benzene/methanol and further separated using high performance liquid chromatography (HPLC). Subfractions from the HPLC separation were analyzed by gas chromatography using both element-specific nitrogen-phosphorus detectors and flame ionization detectors. Microbial mutagenicity assay results indicated that the crude organic extracts were mutagenic, and that both the specific activity and the overall activity of the PCC material was greater than that of the FBC material. Comparison of results from assays using S. typhimurium, TA1538NR indicated that nitrated polycyclic aromatic compounds (PAC) were responsible for much of the mutagenic activity of the PCC material. Similar results were obtained for assays of the FBC organic extract with standard and nitroreductase-deficient strains of S. typhimurium, TA100 and TA1538. Mutagenically active HPLC fractions were analyzed using high resolution gas chromatography (HRGC) and GC mass spectrometry (GC/MS), as well as probe inlet low and high resolutions MS. The discovery and identification of nitrated, oxygenated PAC are important because the presence of both nitro and/or keto functionalities on certain PAC has been shown to confer or enhance mutagenic activity.

  10. APPLICATION OF ADVANCED TECHNOLOGY FOR NOX CONTROL: ALTERNATE FUELS AND FLUIDIZED-BED COAL COMBUSTION

    EPA Science Inventory

    The paper discusses the effect of alternate fuels and fluidized coal combustion in controlling the emission of nitrogen oxides (NOx). The current trend in energy use in the U.S. is toward greater use of coal and coal derived fuels, and on ensuring that these fuels are produced an...

  11. Tube construction for fluidized bed combustor

    DOEpatents

    De Feo, Angelo (Totowa, NJ); Hosek, William (Mt. Tabor, NJ)

    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.

  12. Fluidized bed combustor and tube construction therefor

    DOEpatents

    De Feo, Angelo (Passaic, NJ); Hosek, William (Morris, NJ)

    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.

  13. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system. Quarterly progress report, October 1-December 31, 1982

    SciTech Connect

    1983-04-21

    The overall objective of the Westinghouse coal gasification program is to demonstrate the viability of the Westinghouse pressurized, fluidized bed, gasification system for the production of medium-Btu fuel gas for syngas, electrical power generation, chemical feedstocks, or industrial fuels and to obtain performance and scaleup data for the process and hardware. Progress reports are presented for the following tasks: (1) operation and maintenance of the process development unit (PDU); (2) process analysis; (3) cold flow scaleup facility; (4) process component engineering and design; and (5) laboratory support studies involving gas solids flow modeling and coal/ash behavior. 9 figures, 19 tables.

  14. The O{sub 2}-enriched air gasification of coal, plastics and wood in a fluidized bed reactor

    SciTech Connect

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

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer The effect of the O{sub 2} in the gasification stream of a BFB gasifier has been studied. Black-Right-Pointing-Pointer Main advantage of the O{sub 2}-enriched air is the increasing of the bed temperature. Black-Right-Pointing-Pointer No remarkable effects on tar reduction. Decreasing of recognized PAHs. Black-Right-Pointing-Pointer Gasification reactions completed inside the dense bed and splashing zone. Black-Right-Pointing-Pointer Polycondensation reactions occur mainly in the freeboard region. - Abstract: The effect of oxygen-enriched air during fluidized bed co-gasification of a mixture of coal, plastics and wood has been investigated. The main components of the obtained syngas were measured by means of on-line analyzers and a gas chromatograph while those of the condensate phase were off-line analysed by means of a gas chromatography-mass spectrometer (GC-MS). The characterization of condensate phase as well as that of the water used as scrubbing medium completed the performed diagnostics. The experimental results were further elaborated in order to provide material and substances flow analyses inside the plant boundaries. These analyses allowed to obtain the main substance distribution between solid, gaseous and condensate phases and to estimate the conversion efficiency of carbon and hydrogen but also to easily visualise the waste streams produced by the process. The process performance was then evaluated on the basis of parameters related to the conversion efficiency of fuels into valuable products (i.e. by considering tar and particulate as process losses) as well as those related to the energy recovery.

  15. Characterization of fly ashes from circulating fluidized bed combustion (CFBC) boilers cofiring coal and petroleum coke

    SciTech Connect

    Feihu Li; Jianping Zhai; Xiaoru Fu; Guanghong Sheng

    2006-08-15

    The chemistry, mineralogy, morphology, and particle size distribution were investigated in fly ashes from the burning of Datong (ShanXi, China) bituminous coal and the cofiring of Mideast high-sulfur petroleum coke (PC) with 30:70 (cal %) and 50:50 (cal %) blends of Datong bituminous coal in two commercial CFBC boilers. With the exception of CaO, the amounts of major oxides in the fly ashes from cofiring PC and coal were close to those of the common coal fly ashes. The PC-coal fly ashes were enriched in Ni, V, and Mo, implying these trace elements were mainly derived from PC. Ni and V, along with several other elements, such as Cr, Cu, Se, Pb, U, Th, and possibly As and Cd, increased in content with a decrease in temperature of the electrostatic precipitator (ESP). The results of chemistry, mineralogy, and morphology studies suggested that the desulfurization rate of the CFBC boilers at current conditions was low, and the PC tends to coarsen the fly ash particles and increase the loss on ignition (LOI) values, making these fly ashes unsuitable for use as a cement additive or a mineral admixture in concrete. Further studies on the combustion status of the CFBC boilers are needed if we want to be able to increase the desulfurization rate and produce high-quality fly ashes for broader and full utilization. 22 refs., 4 figs., 4 tabs.

  16. UTILITY BOILER DESIGN/COST COMPARISON: FLUIDIZED-BED COMBUSTION VS. FLUE GAS DESULFURIZATION

    EPA Science Inventory

    The report gives results of a conceptual design, performance, and cost comparison of utility scale (750-925 MWe) coal-burning power plants employing three alternative technologies: conventional boiler with a stack gas scrubber (CWS), atmospheric-pressure fluidized-bed combustion ...

  17. Impact of the addition of chicken litter on mercury speciation and emissions from coal combustion in a laboratory-scale fluidized bed combustor

    SciTech Connect

    Songgeng Li; Shuang Deng; Andy Wu; Wei-ping Pan

    2008-07-15

    Co-combustion of chicken litter with coal was performed in a laboratory-scale fluidized bed combustor to investigate the effect of chicken litter addition on the partitioning behavior of mercury. Gaseous total and elemental mercury concentrations in the flue gas were measured online, and ash was analyzed for particle-bound mercury along with other elemental and surface properties. The mercury mass balance was between 85 and 105%. The experimental results show that co-combustion of chicken litter decreases the amount of elemental and total mercury in the gas phase. Mercury content in fly ash increases with an increasing chicken litter share. 22 refs., 6 figs., 5 tabs.

  18. Decontamination of Aspergillus flavus and Aspergillus parasiticus spores on hazelnuts via atmospheric pressure fluidized bed plasma reactor.

    PubMed

    Dasan, Beyhan Gunaydin; Mutlu, Mehmet; Boyaci, Ismail Hakki

    2016-01-01

    In this study, an atmospheric pressure fluidized bed plasma (APFBP) system was designed and its decontamination effect on aflatoxigenic fungi (Aspergillus flavus and Aspergillus parasiticus) on the surface of hazelnuts was investigated. Hazelnuts were artificially contaminated with A. flavus and A. parasiticus and then were treated with dry air plasma for up to 5min in the APFBP system at various plasma parameters. Significant reductions of 4.50 log (cfu/g) in A. flavus and 4.19 log (cfu/g) in A. parasiticus were achieved after 5min treatments at 100% V - 25kHz (655W) by using dry air as the plasma forming gas. The decontamination effect of APFBP on A. flavus and A. parasiticus spores inoculated on hazelnuts was increased with the applied reference voltage and the frequency. No change or slight reductions were observed in A. flavus and A. parasiticus load during the storage of plasma treated hazelnuts whereas on the control samples fungi continued to grow under storage conditions (30days at 25°C). Temperature change on hazelnut surfaces in the range between 35 and 90°C was monitored with a thermal camera, and it was demonstrated that the temperature increase taking place during plasma treatment did not have a lethal effect on A. flavus and A. parasiticus spores. The damage caused by APFBP treatment on Aspergillus spp. spores was also observed by scanning electron microscopy. PMID:26398284

  19. Preliminary comparison of theory and experiment for a conical, pressurized-fluidized-bed coal combustor

    NASA Technical Reports Server (NTRS)

    Patch, R. W.

    1979-01-01

    A published model was used for a comparison of theory with an actual combustor burning caking bituminous coal and using limestone to reduce sulfur dioxide emission. Theoretical bed pressure drop was in good agreement with experiment. The burnable carbon elutriated was not in agreement with experiment, at least partly because the exhaust port was apparently below the transport disengaging height. The observed nitrogen oxides emission rate was about half the theoretical value. There was order-or-magnitude agreement of sulfur dioxide emission rates.

  20. Fluidized bed sulfur dioxide removal

    SciTech Connect

    Nguyen, X.T.

    1982-01-05

    A system is disclosed for reducing the emission of sulfur particularly for high sulfur coal combustion in a fluidized bed by injecting limestone into the bed and calcining the limestone in the bed to form lime. A portion of the lime so formed is reacted with a portion of the SO2 generated in the bed, removing the excess of material containing lime so generated from the bed. Excess lime is slaked in water, then contacted with the flue gases leaving the fluid bed and containing SO2 with the lime slurry so formed thereby removing a further significant portion of the generated SO2 from the flue gas.

  1. FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

    SciTech Connect

    Bruce G. Miller; Sharon Falcone Miller; Robert Cooper; Douglas Donovan; John Gaudlip; Matthew Lapinsky; William Serencsits; Neil Raskin; Tom Steitz

    2002-07-12

    The Pennsylvania State University, under contract to the U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL) is performing a feasibility analysis on installing a state-of-the-art circulating fluidized bed (CFB) boiler and ceramic filter emission control device at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring multiple biofuels and coal-based feedstocks. Penn State currently operates an aging stoker-fired steam plant at its University Park campus and has spent considerable resources over the last ten to fifteen years investigating boiler replacements and performing life extension studies. This effort, in combination with a variety of agricultural and other wastes generated at the agricultural-based university and the surrounding rural community, has led Penn State to assemble a team of fluidized bed and cofiring experts to assess the feasibility of installing a CFB boiler for cofiring biomass and other wastes along with coal-based fuels. The objective of the project is being accomplished using a team that includes personnel from Penn State's Energy Institute, Office of Physical Plant, and College of Agricultural Sciences; Foster Wheeler Energy Services, Inc.; Parsons Energy and Chemicals Group, Inc.; and Cofiring Alternatives.

  2. FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

    SciTech Connect

    Bruce G. Miller; Sharon Falcone Miller; Robert Cooper; Douglas Donovan; John Gaudlip; Matthew Lapinsky; William Serencsits; Neil Raskin; Dale Lamke

    2001-10-12

    The Pennsylvania State University, under contract to the U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL) is performing a feasibility analysis on installing a state-of-the-art circulating fluidized bed (CFB) boiler and ceramic filter emission control device at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring multiple biofuels and coal-based feedstocks. Penn State currently operates an aging stoker-fired steam plant at its University Park campus and has spent considerable resources over the last ten to fifteen years investigating boiler replacements and performing life extension studies. This effort, in combination with a variety of agricultural and other wastes generated at the agricultural-based university and the surrounding rural community, has led Penn State to assemble a team of fluidized bed and cofiring experts to assess the feasibility of installing a CFB boiler for cofiring biomass and other wastes along with coal-based fuels.

  3. FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

    SciTech Connect

    Bruce G. Miller; Sharon Falcone Miller; Robert Cooper; Douglas Donovan; John Gaudlip; Matthew Lapinsky; William Serencsits; Neil Raskin; Dale Lamke; Joseph J. Battista

    2001-03-31

    The Pennsylvania State University, under contract to the U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL) is performing a feasibility analysis on installing a state-of-the-art circulating fluidized bed (CFB) boiler and ceramic filter emission control device at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring multiple biofuels and coal-based feedstocks. Penn State currently operates an aging stoker-fired steam plant at its University Park campus and has spent considerable resources over the last ten to fifteen years investigating boiler replacements and performing life extension studies. This effort, in combination with a variety of agricultural and other wastes generated at the agricultural-based university and the surrounding rural community, has led Penn State to assemble a team of fluidized bed and cofiring experts to assess the feasibility of installing a CFB boiler for cofiring biomass and other wastes along with coal-based fuels. The objective of the project is being accomplished using a team that includes personnel from Penn State's Energy Institute and the Office of Physical Plant, Foster Wheeler Energy Services, Inc., and Cofiring Alternatives.

  4. Modeling of NOx emissions from fluidized bed combustion of high volatile lignites

    SciTech Connect

    Afacan, O.; Gogebakan, Y.; Selcuk, N.

    2007-01-15

    A comprehensive model, previously developed and tested for prediction of behavior of continuous fluidized bed combustors is extended to incorporate NOx formation and reduction reactions and applied to the simulation of Middle East Technical University (METU) 0.3 MW Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) burning lignites with high Volatile Matter/Fixed Carbon (VM/FC) ratios in their own ashes. Favorable comparisons are obtained between the predicted and measured temperatures and concentrations of gaseous species along the combustor. Results show that determination of partitioning of coal nitrogen into char-N and volatile-N, char combustion rate, and amount of volatile nitrogen released along the combustor are found to be the most important parameters that affect NO formation and reduction in bubbling fluidized bed combustors.

  5. 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.

  6. A descriptive model for sulfur capture in bubbling atmospheric pressure fluidized bed combustors

    SciTech Connect

    Walsh, P.M.

    1995-12-31

    A model of sorbent behavior is proposed for interpretation of measurements of sulfur capture in large-scale bubbling atmospheric pressure fluidized bad combustors (AFBC). The objective is to account for effects of the stone feed size distribution, attrition, recycle ratio, sulfation capacity, and sulfation rate on sulfur capture in practical systems. The parameters used in the simulation are limited to those whose values can be estimated from measurements in full-scale plants. Fines introduced with the limestone feed or formed on calcination, fines generated by attrition of bed particles, sulfur capture in the freeboard, and fines recycle were included in the description of the system. The sorbent was characterized by its sulfation capacity, fines content, attrition coefficient, and a first-order rate coefficient for reaction with SO{sub 2}. The model was compared with measurements by the Tennessee Valley Authority (TVA) and Electric Power Research Institute (EPRI) in the TVA 20 MW AFBC (TVA and EPRI, 1984), Measurements of sulfur capture over the range of recycle ratios from 0 to 4 kg recycle/kg coal, and calcium-to-sulfur ratios from 1.5 to 5 kmol Ca/kmol S, were reproduced with an average error of 5% sulfur capture. The principal source of error is thought to be neglect of fines formation during calcination of the stone. With further refinement the approach may be useful for characterization of sorbents in pilot and industrial-scale systems, and for evaluation of the effects of changes in operating conditions on sorbent performance in existing units.

  7. FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

    SciTech Connect

    Bruce G. Miller; Sharon Falcone Miller; Robert Cooper; John Gaudlip; Matthew Lapinsky; Rhett McLaren; William Serencsits; Neil Raskin; Tom Steitz; Joseph J. Battista

    2003-03-26

    The Pennsylvania State University, utilizing funds furnished by the U.S. Department of Energy's Biomass Power Program, investigated the installation of a state-of-the-art circulating fluidized bed boiler at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring biofuels and coal-based feedstocks. The study was performed using a team that included personnel from Penn State's Energy Institute, Office of Physical Plant, and College of Agricultural Sciences; Foster Wheeler Energy Services, Inc.; Foster Wheeler Energy Corporation; Parsons Energy and Chemicals Group, Inc.; and Cofiring Alternatives. The activities included assessing potential feedstocks at the University Park campus and surrounding region with an emphasis on biomass materials, collecting and analyzing potential feedstocks, assessing agglomeration, deposition, and corrosion tendencies, identifying the optimum location for the boiler system through an internal site selection process, performing a three circulating fluidized bed (CFB) boiler design and a 15-year boiler plant transition plan, determining the costs associated with installing the boiler system, developing a preliminary test program, determining the associated costs for the test program, and exploring potential emissions credits when using the biomass CFB boiler.

  8. Hydrodynamics of fluidized beds using image analysis

    NASA Astrophysics Data System (ADS)

    Hull, Ashley Samuel

    Fluidized beds, originally developed in the 1920s, have become the reactors of choice in several industrial processes. For example, coal combustion within fluidized bed systems has improved efficiency over other combustion technologies. There are however, several issues related to this technology that remain to be resolved. Three of the more significant issues are the dynamics of equal-density particle segregation and the influence of horizontal tube banks on both bubble hydrodynamics and solids mixing. These topics were investigated through the use of video image analysis of thin transparent fluidized beds. Experimental data, obtained from bubbling beds with and without simulated horizontal heat exchanger tubes, were used to evaluate existing hydrodynamic models and derive new semi-empirical models.

  9. Particle withdrawal from fluidized bed systems

    DOEpatents

    Salvador, Louis A. (Greensburg, PA); Andermann, Ronald E. (Arlington Heights, IL); Rath, Lawrence K. (Mt. Pleasant, PA)

    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. Regenerative Portland cement sorbents for fluidized-bed combustion of coal

    SciTech Connect

    Albanese, A S; Sethi, D; Steinberg, M

    1980-01-01

    Portland cements are commercially available construction materials that contain high concentrations of calcium silicates. The silicates are highly reactive towards SO/sub 2/ at temperatures and pressures encountered in atmospheric and pressurized FBC's. Of the Portland cements tested, PC III appears to have the highest sulfation capacity when sulfated by SO/sub 2/ at FBC conditions. A thermodynamic analysis of the sulfation of calcium silicates indicates that they are capable of reducing the concentration of SO/sub 2/ in FBC combustion gases to within the current EPA emission limits. The optimum temperature for sulfation of 16/20 mesh PC III pellets is about 1000/sup 0/C in comparison to about 875/sup 0/ for natural limestones. The higher observed optimum temperature is an advantage because combustion and power cycle efficiencies tend to increase as bed temperature increases. The reactions for regenerating sulfated calcium silicates are similar to those for regenerating calcium sulfate. However, the equilibrium partial pressures of SO/sub 2/ in the reductive decomposition of sulfated silicates are much higher than for sulfate lime. This implies that higher SO/sub 2/ concentrations will be attainable in the regenerator off-gas which will result in more economical conversion of SO/sub 2/ to sulfur or sulfuric acid. The sulfation capacity and regeneration efficiency of PC III pellets do not deteriorate with repeated sulfation/regeneration cycling. This indicates that PC III pellets are suitable for use in regenerative systems. The sulfation capacity of PC III is independent of pressure up to at least 10 atm.

  11. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project. 1989 Annual report, [January 1989--December 1989

    SciTech Connect

    Not Available

    1992-02-01

    The report summarizes unit operating experience and test program progress for 1989 on Colorado-Ute Electric Association`s Nucla CFB Demonstration Program. During this period, the objectives of the Nucla Station operating group were to correct problems with refractory durability, resolve primary air fan capacity limitations, complete the high ash and high sulfur coal tests, switch to Salt Creek coal as the operating fuel, and make the unit available for testing without capacity restrictions. Each of these objectives was addressed and accomplished, to varying degrees, except for the completion of the high sulfur coal acceptance tests. (VC)

  12. Pulsed atmospheric fluidized bed combustion. Technical progress report, January 1, 1993--March 31, 1993

    SciTech Connect

    Not Available

    1993-05-01

    As reported in previous quarterly reports, the fabrication of the fluid bed vessel, hot cyclone, coal handling system components, and coal/limestone feed systems is underway. Procurement of long lead time items was initiated in October 1992, and.deliveries are being made on schedule. In this quarterly period the following design tasks were accomplished. Mass and energy balance review and optimization; system operation calibrations; piping pressure drop design calculations; and pipe sizing and layout drawings.

  13. 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.

  14. FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

    SciTech Connect

    Bruce G. Miller; Curtis Jawdy

    2000-10-09

    The Pennsylvania State University, under contract to the US Department of Energy, National Energy Technology Laboratory is performing a feasibility analysis on installing a state-of-the-art circulating fluidized bed boiler and ceramic filter emission control device at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal or coal refuse, and developing a test program to evaluate cofiring multiple biofuels and coal-based feedstocks. The objective of the project is being accomplished using a team that includes personnel from Penn State's Energy Institute and the Office of Physical Plant, Foster Wheeler Energy Corporation, Foster Wheeler Development Corporation, and Cofiring Alternatives. The major emphasis of work during this reporting period was to assess the types and quantities of potential feedstocks and collect samples of them for analysis. Approximately twenty different biomass, animal waste, and other wastes were collected and analyzed.

  15. ENVIRONMENTAL ASPECTS OF FLUIDIZED-BED COMBUSTION

    EPA Science Inventory

    The report reviews the environmental aspects of fluidized-bed combustion (FBC) with respect to environmental media and specific pollutants. Emissions data indicate that FBC technology is a viable alternative to conventional coal combustion. Adverse impacts on health or the enviro...

  16. State of the art of pressurized fluidized bed combustion systems

    SciTech Connect

    Graves, R.L.

    1980-09-01

    This report was prepared at the request of the Tennessee Valley Authority (TVA) to clarify the development status of the pressurized fluidized bed combustor (PFBC) and to place in perspective the problems which are yet to be solved before commercialization of the concept is practical. This report, in essence, supersedes the interim report published in 1979, Assessment of the State of the Art of Pressurized Fluidized Bed Combustion Systems. A brief overview of the PFBC concept is included citing potential advantages and disadvantages relative to atmospheric fluidized bed combustion (AFBC) and conventional pulverized coal plants. A survey of existing and developing PFBC experimental facilities is presented in some detail which includes the major accomplishments at the respective facilities. Recent data on plant emissions, turbine/gas cleanup systems, and overall efficiency are provided. Findings of several design studies are also discussed. The results of recent gas turbine and cascade tests have been encouraging although the full assessment of the accomplishments have not been made. The delay in construction of the Grimethorpe plant causes further delay in proof-testing full-size, rotating turbomachinery. Several parameters are recommended for further assessment in design studies including: (1) effect of turbine life on cost of power; and (2) effect of reduced gas turbine inlet temperature and pressure on cost of power.

  17. Fluid dynamics of a fluidized bed packed with heat exchangers

    NASA Astrophysics Data System (ADS)

    Zakkay, V.; Miller, G.; Kolar, A.; Franceschi, J.; Panunzio, S.; Skelley, W.; Ho, C. C.; Brentan, A.; Kiviat, G.; Rosen, S.

    1981-04-01

    Tests of two fluidized bed facilities are described. Bed dynamics of a one foot gas fired fluidized bed (GFFB) and its interrelation with the heat transfer characteristics of immersed heat exchangers of different configurations were studied. The GFFB, capable of achieving different gas velocity distributions in the bed with the help of a specially designed gas distributor, was operated to gain useful information on the influence of various operating parameters, such as the superficial gas velocity and its profile, the bed temperature and pressure, and settled bed height, on the bed expansion and heat transfer characteristics of vertica and horizontal tube bundles, and an inverted U-tube. Tests were also performed on an inverted U-tube with longitudinal fins, and two unfinned inverted U-tubes to study the effect of heat exchanger solidity. Particle attrition studies were also performed at atmospheric pressure. A one-foot, coal-fired fluidized bed was also built and initial tests were performed. Typical heat transfer and particle attrition data were collected with a single vertical tube heat exchanger axially located in the bed. The behavior of deep and shallow beds, as observed in the GFFB, was confirmed.

  18. Atmospheric fluidized bed combustion advanced system concepts applicable to small industrial and commercial markets. Topical report, Level 2

    SciTech Connect

    Ake, T.R.; Dixit, V.B.; Mongeon, R.K.

    1992-09-01

    As part of an overall strategy to promote FBC coal combustion and to improve the marketability of the eastern coals, the US Department of Energy`s Morgantown Energy Research Center awarded a three level contract to Riley Stoker Corporation to develop advanced Multi Solids Fluidized Bed (MSFB) boiler designs. The first level of this contract targeted the small package boiler (10,000--50,000 lb/hr steam) and industrial size boiler (75,000--150,000 lb/hr steam) markets. Two representative sizes, 30,000 lb/hr and 110,000 lb/hr of steam, were selected for the two categories for a detailed technical and economic evaluation. Technically, both the designs showed promise, however, the advanced industrial design was favored on economic considerations. It was thus selected for further study in the second level of the contract. Results of this Level-2 effort, presented in this report, consisted of testing the design concept in Riley`s 4.4 MBtu/hr pilot MSFB facility located at Riley Research Center in Worcester, Mass. The design and economics of the proof of concept facility developed in Level-1 of the contract were then revised in accordance with the findings of the pilot test program. A host site for commercial demonstration in Level-3 of the contract was also secured. It was determined that co-firing coal in combination with paper de-inking sludge will broaden the applicability of the design beyond conventional markets. International Paper (IP), the largest paper company in the world, is willing to participate in this part of the program. IP has offered its Hammermill operation at Lockhaven, Pa, site of a future paper de-inking plant, for the proof of concept installation. This plant will go in operation in 1994. It is recommended that METC proceed to the commercial demonstration of the design developed. The approach necessary to satisfy the needs of the customer while meeting the objectives of this program is presented along with a recommended plan of action.

  19. Pulsed atmospheric fluidized bed combustion. Quarterly technical progress report, April--June 1993

    SciTech Connect

    Not Available

    1993-07-30

    In this quarter the design of the plant structures was completed 70%. The design philosophy of the structure economizes on the use of steel by providing supports for the hot cyclone and hot gas duct connecting the cyclone to the boiler while fulfilling the needs for platforms and walkways at the various levels necessary for operational access. Figures 1 through 6 indicate the layout of the plant structure. At the same time the structure for the Coarse Coal Silo V-2 and Limestone Silo V-4 were incorporated and completed. Following completion of the piping pressure drop calculations, pipe sizing and layout drawings, detailed drawings of the piping in different views are being prepared. The pulse combustor is used to burn fine coal particles and provide an ignition source and supplementary heat to the fluid bed. The following is a description of the components: air plenum, fine coal injectors, aerovalves, water jacket, and tailpipe inserts.

  20. 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.

  1. Exploratory and basic fluidized-bed combustion studies. Quarterly report, April-June 1980. [Limestone and dolomite; USA

    SciTech Connect

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

    1980-12-01

    This work supports the 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 particles and alkali metal compounds from the flue gas, control of SO/sub 2/ and trace pollutant emissions, and other aspects of fluidized-bed coal combustion. This report presents information on: (1) the development of a sorbent utilization prediction methodology, (2) studies of factors which affect limestone breakup and elutriation, (3) basic studies of limestone sulfation under combustion conditions, and (4) studies of the kinetics of the hydration of spent limestone.

  2. FEASIBILITY ANALYSIS FOR INSTALLING A CIRCULATING FLUIDIZED BED BOILER FOR COFIRING MULTIPLE BIOFUELS AND OTHER WASTES WITH COAL AT PENN STATE UNIVERSITY

    SciTech Connect

    Bruce G. Miller; Sharon Falcone Miller; Robert Cooper; Douglas Donovan; John Gaudlip; Matthew Lapinsky; William Serencsits; Neil Raskin; Tom Steitz

    2002-10-14

    The Pennsylvania State University, under contract to the U.S. Department of Energy, National Energy Technology Laboratory is performing a feasibility analysis on installing a state-of-the-art circulating fluidized bed boiler and ceramic filter emission control device at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring multiple biofuels and coal-based feedstocks. The objective of the project is being accomplished using a team that includes personnel from Penn State's Energy Institute, Office of Physical Plant, and College of Agricultural Sciences; Foster Wheeler Energy Services, Inc.; Parsons Energy and Chemicals Group, Inc.; and Cofiring Alternatives. During this reporting period, the final technical design and cost estimate were submitted to Penn State by Foster Wheeler. In addition, Penn State initiated the internal site selection process to finalize the site for the boiler plant.

  3. Gas phase hydrodynamics inside a circulating fluidized bed

    E-print Network

    Moran, James C. (James Christopher)

    2001-01-01

    Circulating Fluidized Beds (CFB's) offer many advantages over traditional pulverized coal burners in the power generation industry. They operate at lower temperatures, have better environmental emissions and better fuel ...

  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

    SciTech Connect

    Yan Cao; Hongcang Zhou; Junjie Fan; Houyin Zhao; Tuo Zhou; Pauline Hack; Chia-Chun Chan; Jian-Chang Liou; Wei-ping Pan

    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{sup o}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. 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{sup o}C in the upper part of the fluidized bed combustor seemed to be responsible for the reduction of gaseous chlorine and, consequently, limited mercury emissions reduction during cofiring. 36 refs., 3 figs. 1 tab.

  5. Heat transfer in circulating fluidized bed combustor

    SciTech Connect

    Bucak, O.; Dogan, O.M.; Uysal, B.Z.

    1999-07-01

    The importance of fluidized bed combustion in utilizing the energy of especially low quality coals is widely accepted. Among various fluidized bed combustion technologies, circulating fluidized beds are preferred as a result of the efforts to get higher combustion efficiencies. The aim of the present research was to investigate the applicability of this technology to Turkish lignites. To achieve this object a 6.5 m tall pilot circulating fluidized bed combustor with 155 mm diameter and all the auxiliary equipment were designed, constructed and tested using Seyitomer lignite of 0.9--2.38 mm in size. Heat transfer from the bed to the water cooling jackets was examined to recover the combustion energy. The inside heat transfer coefficient was determined to be around 121 W/m{sup 2} K for the suspension density of 20--55 kg/m{sup 3}. The agreement of the experimental findings with theoretical estimations was also checked. Furthermore, the thermal efficiency of the system for the heat recovered was found to be 63%.

  6. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system: Topical report, Process analysis, FY 1983

    SciTech Connect

    1987-07-31

    KRW Energy Systems, Inc., is engaged in the continuing development of a pressurized, fluidized-bed gasification process at its Waltz Mill Site in Madison, Pennsylvania. The overall objective of the program is to demonstrate the viability of the KRW process for the environmentally-acceptable production of low- and medium-Btu fuel gas from a variety of fossilized carbonaceous feedstocks and industrial fuels. This report presents process analysis of the 24 ton-per-day Process Development Unit (PDU) operations and is a continuation of the process analysis work performed in 1980 and 1981. Included is work performed on PDU process data; gasification; char-ash separation; ash agglomeration; fines carryover, recycle, and consumption; deposit formation; materials; and environmental, health, and safety issues. 63 figs., 43 tabs.

  7. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D. (Oak Ridge, TN)

    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.

  8. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D. (Oak Ridge, TN); Marasco, Joseph A. (Kingston, TN)

    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.

  9. 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.

  10. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D. (Oak Ridge, TN); Marasco, Joseph A. (Kingston, TN)

    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.

  11. 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.

  12. 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.

  13. Fast fluidized bed steam generator

    DOEpatents

    Bryers, Richard W. (Flemington, NJ); Taylor, Thomas E. (Bergenfield, NJ)

    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.

  14. Energy and environmental research emphasizing low-rank coal -- Task 3.8, Pressurized fluidized-bed combustion

    SciTech Connect

    Mann, M.D.; Henderson, A.K.; Swanson, M.L.

    1995-03-01

    The goal of the PFBC activity is to generate fundamental process information that will further the development of an economical and environmentally acceptable second-generation PFBC. The immediate objectives focus on generic issues, including the performance of sulfur sorbents, fate of alkali, and the Resource Conservation and Recovery Act (RCRA) heavy metals in PFBC. A great deal of PFBC performance relates to the chemistry of the bed and the contact between gas and solids that occurs during combustion. These factors can be studied in a suitably designed bench-scale reactor. The present studies are focusing on the emission control strategies applied in the bed, rather than in hot-gas cleaning. Emission components include alkali and heavy metals in addition to SO{sub 2}, NO{sub x}, N{sub 2}O, and CO. The report presents: a description of the pressurized fluidized-bed reactor (PFBR); a description of the alkali sampling probe; shakedown testing of the bench-scale PFBR; results from alkali sampling; results from sulfur sorbent performance tests; and results from refuse-derived fuel and lignite combustion tests.

  15. 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.

  16. 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.

  17. Economic Evaluation of By-Product Power/Co-Generation Systems for Industrial Plants with Fluidized-Bed Coal Burning Facilities 

    E-print Network

    Mesko, J. E.

    1980-01-01

    . The plants analyzed employ fluidized bed boilers for generation of steam for process and building/heating/cooling demands, in conjunction with electric power co-generation. Results of the analysis are presented, using life cycle costs and investment payback...

  18. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume IV. FBC-Model-II manual

    SciTech Connect

    Louis, J.F.; Tung, S.E.

    1980-10-01

    This document is the fourth of the seven volume series of our Phase II Final Report. The purpose of this manual is to describe how to access and use M.I.T.'s Fluidized Bed Combustor (FBC) System Program. Presently, the FBC program is stored in a Honeywell Computer System and can be accessed using the Multics interactive system. The intention in writing this manual is to answer the questions that may arise regarding the mechanics of operating the system program, as well as warn the user of possible pitfalls and mistakes that could be made. No attempt is made here to describe the internals of the systems program. The manual describes the procedures an individual would follow to become an active user of the system program. It then explains the various options available for reaching the Multics interactive system on Honeywell 6180 computer on which the program runs. For users outside the Metropolitan Boston area, a public network for data communications is described which is relatively inexpensive. As the system program is approached through Multics using a special command facility TPSA, a separate introduction is provided for Multics TPSA. This facility allows commands appropriate for testing the program and carrying out parametric studies to be executed in a convenient way. Multics TPSA was formulated to meet the needs of the FBC project in particular. Finally, some sample sessions are presented which illustrate the login and logout procedures, the command language, and the data manipulation features of the FBC program. The use of commands helpful in debugging the program is also illustrated.

  19. Eighth annual fluidized bed conference

    SciTech Connect

    Not Available

    1992-01-01

    Fourteen paper were presented at the Eighth Annual Fluidized Bed Conference held on December 8-9, 1992 in Pittsburgh, PA. A separate abstract was prepared for each paper for the Energy Science and Technology Database.

  20. Seventh annual fluidized bed conference

    SciTech Connect

    Not Available

    1991-01-01

    Thirteen papers were presented at the Seventh Annual Fluidized Bed Conference held on December 9-10, 1991 in Indianapolis, Indiana. A separate abstract was prepared for each paper for inclusion in the Energy Science and Technology Database.

  1. Application of noncatalytic gas-solid reactions for a single pellet of changing size to the modeling of fluidized-bed combustion of coal char containing sulfur

    SciTech Connect

    Rehmat, A.; Saxena, S.C.; Land, R.H.

    1980-09-01

    A mechanistic model is developed for coal char combustion, with sulfur retention by limestone or dolomite sorbent, in a gas fluidized bed employing noncatalytic single pellet gas-solid reactions. The shrinking core model is employed to describe the kinetics of chemical reactions taking place on a single pellet; changes in pellet size as the reaction proceeds are considered. The solids are assumed to be in back-mix condition whereas the gas flow is regarded to be in plug flow. Most char combustion occurs near the gas distributor plate (at the bottom of the bed), where the bubbles are small and consequently the mass transfer rate is high. For such a case, the analysis is considerably simplified by ignoring the bubble phase since it plays an insignificant role in the overall rate of carbon conversion. Bubble-free operation is also encounterd in the turbulent regime, where the gas flow is quite high and classical bubbles do not exist. Formulation of the model includes setting up heat and mass balance equations pertaining to a single particle (1) exposed to a varying reactant concentration along the height of the bed and (2) whose size changes during reaction. These equations are then solved numerically to account for particles of all sizes in the bed in obtaining the overall carbon conversion efficiency and resultant sulfur retention. In particular, the influence on sorbent requirement of several fluid-bed variables such as oxygen concentration profile, particle size, reaction rate for sulfation reaction, and suflur adsorption efficiency are examined.

  2. Design of entrained-flow and moving-, packed-, and fluidized-bed sorption systems: Grain-model kinetics for hot coal-gas desulfurization with limestone

    SciTech Connect

    Fenouil, L.A.; Lynn, S.

    1996-04-01

    Concentration profiles in several configurations of sorption systems (moving, packed, and fluidized beds and entrained-flow) were determined using the grain and the unreacted shrinking core model for the description of the gas-solid reaction kinetics. General equations for the design and analysis of all these reactor configurations are given, and simple analytical solutions are proposed. The behavior of these reactors can be expressed as a function of only four parameters: the size of the sorbent pellet and the Peclet, Sherwood (or Biot), and Damkoehler numbers. These general equations were then applied to the lime(stone)/H{sub 2}S systems. Using limestone particles with diameters on the order of 100 {mu}m for entrained-flow and with diameters on the order of 1 mm for the other configurations, it was found that H{sub 2}S could be removed from the hot coal gas to near its equilibrium value with more than 75% sorbent utilization and with reasonable bed depth (about 1 m, or 1-s contact time for entrained-flow) when the reactor temperature is maintained 25--50 C above the calcination temperature of the calcium carbonate.

  3. Decreased gas consumption of a fluidized bed furnace

    NASA Astrophysics Data System (ADS)

    Chen, Yong-Chwang

    1993-10-01

    The feasibility of utilizing a closed circulatory system to generate gases for a fluidized bed furnace was investigated with the primary concentrations of both economizing on the raw materials used for producing furnace atmospheres and decreasing the air pollution caused by exhaust gases. Air humidified with water vapor was first introduced into a charcoal furnace for causing a reaction with hot charcoal to form a carburizing atmosphere. This atmosphere was then introduced into a fluidized bed furnace to carburize steels. The exhaust gases from the fluidized bed furnace were recycled by repassing them through the hot charcoal layer in the charcoal furnace with a gas pump. The charcoal furnace and the fluidized bed furnace formed a closed circulatory system during the carburization of steels. Experiments were performed with various parameters of this system, including content of water vapor in the humid air, temperature of the charcoal, rate of recirculation of the atmosphere, etc. The effect of each parameter on the carburizing behavior in the fluidized bed furnace was investigated on the basis of the rate of carburization and the carbon potential of the atmosphere. The feasibility of applying this system to a fluidized bed furnace was assessed from the aspects of the fluidization of A12O3 powder, the result of carburizing steel, and the rate of consumption of charcoal. The closed system employed in generating atmosphere was demonstrated by the experimental results to have enabled the fluidized bed furnace to operate normally and to have significantly decreased both the consumption rate of charcoal and the environmental pollution.

  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 (Karhula, FI)

    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. Pressurized fluidized-bed combustion

    SciTech Connect

    Not Available

    1980-10-01

    The US DOE pressurized fluidized bed combustion (PFBC) research and development program is designed to develop the technology and data base required for the successful commercialization of the PFBC concept. A cooperative program with the US, West Germany, and the UK has resulted in the construction of the 25 MWe IEA-Grimethorpe combined-cycle pilot plant in England which will be tested in 1981. A 13 MWe coal-fired gas turbine (air cycle) at Curtis-Wright has been designed and construction scheduled. Start-up is planned to begin in early 1983. A 75 MWe pilot plant is planned for completion in 1986. Each of these PFBC combined-cycle programs is discussed. The current status of PFB technology may be summarized as follows: turbine erosion tolerance/hot gas cleanup issues have emerged as the barrier technology issues; promising turbine corrosion-resistant materials have been identified, but long-term exposure data is lacking; first-generation PFB combustor technology development is maturing at the PDU level; however, scale-up to larger size has not been demonstrated; and in-bed heat exchanger materials have been identified, but long-term exposure data is lacking. The DOE-PFB development plan is directed at the resolution of these key technical issues. (LCL)

  7. Mining: Density Separation in Complex-Mode Vibration Fluidized Beds

    SciTech Connect

    Poole, L.; Recca, L.

    1999-01-29

    By eliminating the need to process coal through a conventional wet slurry removal process, these innovative vibrating beds save energy and time. This invention was developed to used in coal and minerals processing sectors of mining. However, it has potential applications to many other processing steps where fluidized beds are used, such as in food processing and energy production

  8. 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.

  9. Characterization of ashes from co-combustion of refuse-derived fuel with coal, wood and bark in a fluidized bed

    SciTech Connect

    Zevenhoven, R.; Skrifvars, B.J.; Hupa, M.

    1998-12-31

    The technical and environmental feasibility of co-combustion of a recovered fuel (RF) prepared from combustible waste fractions (separated at the source), together with coal, peat, wood or wood-waste in thermal power/electricity generation has been studied in several R and D projects within Finland. The current work focuses on eventual changes in ash characteristics during co-combustion of RF with coal, wood or bark, which could lead to bed agglomeration, slagging, fouling and even corrosion in the boiler. Ashes were produced in a 15 kW bubbling fluidized bed (BFB) combustion reactor, the fly ash captured by the cyclone was further analyzed by XRF. The sintering tendency behavior of these ashes was investigated using a test procedure developed at Aabo Akademi University. Earlier, a screening program involved ashes from RF (from a waste separation scheme in Finland) co-combustion with peat, wood and bark, in which ash pellets were thermally treated in air. This showed significant sintering below 600 C as well as above 800 C for RF/wood and RF/bark, but not for RF/peat. This seemed to correlate with alkali chloride and sulfate concentrations in the ashes. The current work addresses a Danish refuse-derived fuel (RDF), co-combusted with bark, coal, bark+coal, wood, and wood+coal (eight tests). Ash pellets were thermally treated in nitrogen in order to avoid residual carbon combustion. The results obtained show no sintering tendencies below 600 C, significant changes in sintering are seen with pellets treated at 1,000 C. Ash from 100% RDF combustion does not sinter, 25% RDF co-combustion with wood and peat, respectively, gives an insignificant effect. The most severe sintering occurs during co-combustion of RDF with bark. Furthermore, it appears that the presence of a 25% coal fraction (on energy basis) seems to have a negative effect on all fuel blends. Analysis of the sintering results versus ash chemical composition shows that, in general, an increased level of alkali chlorides and sulfates gives increased sintering. At the same time, increased amounts calcium salts in the ash appear to reduce sintering tendency. Thus, the results suggest that a calcium based sorbent for SO{sub 2} and HCl capture might reduce problems related to ash sintering. An extensive literature exists, however, that states otherwise.

  10. 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.

  11. 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.

  12. Study of Nox Emission Characteristics of a 1025t/h Coal-Fired Circulating Fluidized Bed Boiler

    NASA Astrophysics Data System (ADS)

    Li, Q. Y.; Mi, Z. D.; Zhang, Q. F.

    Measurements of emission are carried out in a 1025t/h CFB boiler. The effect of some factors including coal properties, bed temperature, unit load, excess air on the emission of NOx are investigated. The measurement results show that the N concentration in the coal is dominant parameter to predict the NOx emission from a large-scale CFB boiler. NOx emission from the 1025t/h CFB boiler increases with cyclone temperature and upper pressure drop due to post combustion and external cycle.

  13. Technical advances and new opportunities for fluidized bed combustion

    SciTech Connect

    Alliston, M.G.; Kokko, A.; Martin, B.G.; Olofsson, J.

    1997-12-31

    This paper outlines opportunities for new circulating fluidized bed (CFB) boilers, technical considerations in selecting a fluidized bed boiler, and CFB boiler configuration types and sizes. New opportunities for CFBs include fuel opportunities from coke, mine mouth coals, and waste products, and boiler application opportunities in industrial cogeneration, repowering, and developing nations. Technical considerations discussed for boiler selection are fuel flexibility and environmental aspects. Three boiler configurations are briefly described: (1) water-cooled cyclone with water-cooled loopseal, (2) integral cylindrical cyclone and loopseal, and (3) Cylindrical multi-inlet cyclone. CFB scale-up is also briefly discussed. 3 refs., 3 figs.

  14. Co-combustion of coal and biomass in pulverized fuel and fluidized bed systems -- Activities and research in Europe

    SciTech Connect

    Hein, K.R.G.; Spliethoff, H.

    1999-07-01

    Biomass or sewage sludge utilized as additional fuel in coal combustion systems has consequences on combustion behavior, emissions, corrosion, and residual matter. Therefore, at the beginning of 1993 the European Union within the frame of the APAS program launched a project called ``Combined Combustion of Biomass/Sewage Sludge and Coal''. Within this project, the effects of burning sewage sludge and agricultural residuals such as straw and manure as well as specially grown energy plants in combination with coals of various ranks and origin were studied for the most common large-scale systems in order to establish both the optimum and the technically achievable process modifications necessary for co-combustion. Based on the experience of the APAS program, the objective of a further EU-co-funded project titled ``Operational problems, trace emissions and by-product management for industrial biomass co-combustion'' was to concentrate the research effort on the problem areas like slagging, fouling, corrosion, ash utilization and trace emissions for different co-combustion systems and carefully investigate technical options to avoid these negative effects. The solution of these technical problems is essential for a technically and economically feasible and environmentally advantageous co-combustion and will promote a widespread utilization of existing biomass resources. The project provides a comparison of different biomass co-utilization concepts with regard to fouling, slagging, corrosion, ash utilization and trace emissions. In detail the project incorporated biofuels like wood, wood pulp, bark, straw, wood matter from pressed olive stones and sewage sludge. The major operational problems like slagging, fouling and corrosion were investigated in both PF and CFB units of various scales. Finally the effect of co-combustion on the by-product management - handling, utilization and disposal are evaluated and compared with a pure coal or pure biomass combustion system, respectively. As a further approach to avoid the above problems of co-utilization the pretreatment of biomass to remove the undesired components before combustion has been investigated by washing, pyrolysis or gasification prior to combustion. The potential of utilization the gaseous product from pyrolysis or gasification as reburn fuel for NO reduction was evaluated.

  15. Novel Magnetically Fluidized Bed Reactor Development for the Looping Process: Coal to Hydrogen Production R&D

    SciTech Connect

    Mei, Renwei; Hahn, David; Klausner, James; Petrasch, Jorg; Mehdizadeh, Ayyoub; Allen, Kyle; Rahmatian, Nima; Stehle, Richard; Bobek, Mike; Al-Raqom, Fotouh; Greek, Ben; Li, Like; Chen, Chen; Singh, Abhishek; Takagi, Midori; Barde, Amey; Nili, Saman

    2013-09-30

    The coal to hydrogen project utilizes the iron/iron oxide looping process to produce high purity hydrogen. The input energy for the process is provided by syngas coming from gasification process of coal. The reaction pathways for this process have been studied and favorable conditions for energy efficient operation have been identified. The Magnetically Stabilized Porous Structure (MSPS) is invented. It is fabricated from iron and silica particles and its repeatable high performance has been demonstrated through many experiments under various conditions in thermogravimetric analyzer, a lab-scale reactor, and a large scale reactor. The chemical reaction kinetics for both oxidation and reduction steps has been investigated thoroughly inside MSPS as well as on the surface of very smooth iron rod. Hydrogen, CO, and syngas have been tested individually as the reducing agent in reduction step and their performance is compared. Syngas is found to be the most pragmatic reducing agent for the two-step water splitting process. The transport properties of MSPS including porosity, permeability, and effective thermal conductivity are determined based on high resolution 3D CT x-ray images obtained at Argonne National Laboratory and pore-level simulations using a lattice Boltzmann Equation (LBE)-based mesoscopic model developed during this investigation. The results of those measurements and simulations provide necessary inputs to the development of a reliable volume-averaging-based continuum model that is used to simulate the dynamics of the redox process in MSPS. Extensive efforts have been devoted to simulate the redox process in MSPS by developing a continuum model consist of various modules for conductive and radiative heat transfer, fluid flow, species transport, and reaction kinetics. Both the Lagrangian and Eulerian approaches for species transport of chemically reacting flow in porous media have been investigated and verified numerically. Both approaches lead to correct prediction of hydrogen production rates over a large range of experimental conditions in the laboratory scale reactor and the bench-scale reactor. In the economic analysis, a comparison of the hydrogen production plants using iron/iron oxide looping cycle and the conventional process has been presented. Plant configurations are developed for the iron/iron oxide looping cycle. The study suggests a higher electric power generation but a lower hydrogen production efficiency comparing with the conventional process. Additionally, it was shown that the price of H{sub 2} obtained from our reactor can be as low as $1.7/kg, which is 22% lower than the current price of the H{sub 2} obtained from reforming plants.

  16. Using exergy analysis on circulating fluidized bed combustors

    SciTech Connect

    Grimaldi, C.N. . Ist. di Energetica); Bidini, G. . Dipt. di Energetica)

    1992-01-01

    A second-law analysis using direct and indirect approaches has recently been applied to fluidized bed combustors (FBCs). The indirect balance has allowed study of the loss mechanisms related to chemical reactions, heat transfer, and the release of sensible heat to the environment. This work presents an improvement over the previous effort by considering two additional effects, sulfur retention efficiency and non adiabaticity of the recirculation loop, the latter to account for the radiative heat loss from the recirculating solids. The effects of the recirculation ratio on exergy losses and on the system mass flow rates are examined in an atmospheric fluidized bed combustor.

  17. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume III. Model predictions and results

    SciTech Connect

    Louis, J.F.; Tung, S.E.

    1980-10-01

    This document is the third of a seven volume series of our Phase II Final Report. This volume deals with parametric studies carried out using the FBC model. A comparison with available pilot plant data is included where such data are available. This volume in essence documents model performance; describing predictions on bubble growth, combustion characteristics, sulfur capture, heat transfer and related parameters. The model has approximately forty input variables which are at the disposal of the user. The user has the option to change a few or all of these input variables. In the parametric studies reported here, a large number of input variables whose variation is less critical to the predicted results, were maintained constant at the default values. On the other hand, those parameters whose selection is very important in design and operation of the FBC's were varied in suitable operating regions. The chief among such parameters are: bed temperature, coal feed size distribution (2 parameters), average bed-sorbent size, calcium to sulfur molar ratio, superficial velocity, excess air fraction, and bed weight (or bed height). The computations for obtaining the parametric relationships are based upon selection of a geometrical design for the combustor. Bed cross-section is 6' x 6', bed height is 4', and the freeboard height is 16'. The heat transfer tubes have 2'' OD, a pitch of 10'', and are located on an equilateral triangle pattern. The air distributor is a perforated plate with 0.1'' diameter holes on a rectangular grid with 0.75'' center-to-center spacing.

  18. TRACE AND MINOR ELEMENT REACTIONS IN FLUIDIZED-BED COMBUSTION PROCESSES

    EPA Science Inventory

    The report gives results of thermodynamic equilibrium calculations for anticipated operating ranges for various fluidized-bed combustion (FBC) designs used to predict the potential volatility and interaction of 31 trace and minor elements contained in coal and sorbent feedstocks....

  19. Fluidized bed desulfurization

    NASA Technical Reports Server (NTRS)

    Ravindram, M.; Kallvinskas, J. J. (inventors)

    1985-01-01

    High sulfur content carbonaceous material, such as coal is desulfurized by continuous fluidized suspension in a reactor with chlorine gas, inert dechlorinating gas and hydrogen gas. A source of chlorine gas, a source of inert gas and a source of hydrogen gas are connected to the bottom inlet through a manifold and a heater. A flow controler operates servos in a manner to continuously and sequentially suspend coal in the three gases. The sulfur content is reduced at least 50% by the treatment.

  20. Advanced Fluidized Bed Waste Heat Recovery Systems 

    E-print Network

    Peterson, G. R.

    1988-01-01

    and continually clean the finned tubes in the fluidized beds. Also, only the distributor plate is exposed to the hot fouling and corrosive flue gases since the fluidized bed quickly cools these gases to a uniform 500?F. INTRODUCTION The U. S. Department... particulates in the flue gases. DOE sponsored the development of two fluidized bed systems to recover waste energy from this class of flue gases.* The recovered energy is used for the production of plant or process steam. These fluidized bed systems have...

  1. 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.

  2. COSTS FOR ADVANCED COAL COMBUSTION TECHNOLOGIES

    EPA Science Inventory

    The report gives results of an evaluation of the development status of advanced coal combustion technologies and discusses the preparation of performance and economic models for their application to electric utility plants. he technologies addressed were atmospheric fluidized bed...

  3. Fundamentals of fluidized bed chemical processes

    SciTech Connect

    Yates, J.G.

    1983-01-01

    Chemical processes based on the use of fluidized solids, although widely used on an industrial scale for some four decades, are currently increasing in importance as industry looks for improved methods for handling and reacting solid materials. This book provides background necessary for an understanding of the technique of gas-solid fluidization. Contents: Some Fundamental Aspects of Fluidization-General Features of Gas-Solid Fluidization; Minimum Fluidization Velocity; Inter-particle forces; Liquid-Solid Fluidization; Bubbles; Slugging; Entrainment and Elutriation; Particle Movement; Bed Viscosity; Fluidization Under Pressure. Fluidized-Bed Reactor Models-ome Individual Models; Model Comparisons; Multiple Region Models. Catalytic Cracking-Process Developments Riser Cracking; Catalysis; Process Chemistry; Kinetics; Process Models. Combustion and Gasification-Plant Developments; Oil and Gas Combustion; Desulphurization; No/sub x/ Emissions; Coal Gassification. Miscellaneous Processes-Phthalic Anhydride (1,3-isobezofurandione); Acrylonitrile (prop-3-enenitrile); Vinyl Chloride (chloroethene); Titanium Dioxide; Uranium Processing; Sulphide Roasting; Indexes.

  4. Reactions during the calcination of a limestone under different atmospheres at fluidized bed combustion conditions: A fixed bed reactor study

    SciTech Connect

    Acke, F.; Lindqvist, O.

    1997-12-31

    Calcined limestones have been shown to provide surfaces in a boiler that have importance for heterogeneous reactions such as the direct decomposition of NH{sub 3} to N{sub 2}, and NO reduction by CO and H{sub 2}. When calcination takes place under an NH{sub 3} atmosphere, formation of HCN and HCNO has also been observed. This work concerns a comparison of the calcination process of a natural limestone under NO or NH{sub 3} atmospheres and the influence of the presence of CO, O{sub 2} and SO{sub 2} on the calcination behavior. Results indicate not fully oxidized phases or impurities to be responsible for the NO reduction during calcination. The results for the HCN and HNCO formation are not that conclusive, although steady state experiments over calcined limestone surfaces in a NH{sub 3} and CO, or CO{sub 2} atmosphere reveal a lot of information such as the importance of CO{sub 2} in the HNCO formation.

  5. Fluidized bed deposition of diamond

    DOEpatents

    Laia, Jr., Joseph R. (Los Alamos, NM); Carroll, David W. (Los Alamos, NM); Trkula, Mitchell (Los Alamos, NM); Anderson, Wallace E. (Los Alamos, NM); Valone, Steven M. (Santa Fe, NM)

    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.

  6. Staged cascade fluidized bed combustor

    DOEpatents

    Cannon, Joseph N. (4103 Farragut St., Hyattsville, MD 20781); De Lucia, David E. (58 Beacon St., Apt. No. 2, Boston, MA 02108); Jackson, William M. (5300 McArthur Blvd., NW., Washington, DC 20016); Porter, James H. (P.O. Box 1131, Daggett Ave., Vineyard Haven, MA 02568)

    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.

  7. 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.

  8. Rivesville multicell fluidized-bed boiler. Quarterly technical progress report, October-December 1979

    SciTech Connect

    Not Available

    1980-01-01

    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 pounds of steam per hour. Steam pressure and temperature conditions were selected to meet requirements of the site at which the boiler was installed.

  9. 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.

  10. Method of feeding particulate material to a fluidized bed

    DOEpatents

    Borio, Richard W. (Somers, CT); Goodstine, Stephen L. (Windsor, CT)

    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.

  11. Heat transfer to a stationary and moving sphere immersed in a fluidized bed

    NASA Astrophysics Data System (ADS)

    Desai, Chetan Jitendra

    The motion of submerged objects in fluidized beds and the corresponding improvement in the heat transfer rate has been largely unexplored. This improvement in heat transfer rate is significant in the design and operating cost of industrial fluidized beds that are used for heat treatment of metal objects, solid waste to be burned, gasification of coal particles, freezing of food grains, and coating operation. The heat transfer to a stationary sphere, a vertically downward moving sphere, and an oscillating copper sphere submerged in an air fluidized bed of glass particles was studied with the bed at standard pressure and temperature conditions. Several of the important variables known to influence the heat transfer rate to a stationary sphere in an air fluidized bed were determined as well as the effect of forced linearly downward motion and oscillating motion of the sphere on heat transfer rate.

  12. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system: Phase 2, Final report, May 1, 1983-July 31, 1984

    SciTech Connect

    1987-09-15

    KRW Energy Systems Inc. is engaged in the development of a pressurized, fluidized-bed, gasification process at its Waltz Mill Site in Madison, Pennsylvania. The overall objective of the program is to demonstrate the viability of the KRW process for the environmentally acceptable production of low- and medium-Btu fuel gas from a variety of fossilized, carbonaceous feedstocks for electrical power generation, substitute natural gas, chemical feedstocks, and industrial fuels. This report covers Phase II of the contract period (May 1, 1983 to July 31, 1984) and is a continuation of the work performed in 1983 and reported in the Phase I final report, FE-19122-30. Included is work performed in fiscal 1983 to 1984 on PDU testing, process analysis, cold flow scaleup facility, process and component engineering and design, and laboratory support studies.

  13. Fluidized bed heat treating system

    DOEpatents

    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.

  14. 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.

  15. Decontamination of combustion gases in fluidized bed incinerators

    DOEpatents

    Leon, Albert M. (Mamaroneck, NY)

    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.

  16. TECHNOLOGY OVERVIEW: CIRCULATING FLUIDIZED-BED COMBUSTION

    EPA Science Inventory

    The report summarizes the current technical status of circulating fluidized-bed combustion (CFBC). Companies that are involved in investigating this technology and/or developing commercial systems are discussed, along with system descriptions and available cost information. CFBC ...

  17. Biomass gasification with air in an atmospheric bubbling fluidized bed. Effect of six operational variables on the quality of the produced raw gas

    SciTech Connect

    Narvaez, I.; Orio, A.; Corella, J.; Aznar, M.P.

    1996-07-01

    Biomass gasification with air in a bubbling fluidized bed is studied in a small pilot plant. Variables analyzed are equivalence ratio (from 0.20 to 0.45), temperatures of the gasifier bed (750--850 C) and of its freeboard (500--600 C), H/C ratio in the feed, use of secondary air (10% of the overall) in the freeboard, and addition (2--5 wt %) of a calcined dolomite mixed with the biomass used as the feedstock. Using advanced tar and gas sampling and analysis methods, the gas composition and tar content in the gas are determined and their variation with the operation parameters is given. A statistical analysis of the effects of the gasification variables is also here presented.

  18. Fluidized-bed boilers keep Chinese industry running on marginal fuels

    SciTech Connect

    Schwieger, B.

    1983-03-01

    Two thousand atmospheric fluidized bed (AFB) boilers are in use in the People's Republic of China. The major Chinese objective is the use of local fuels--oil shale, char from coal-gasification processes and lignite--all of which is of poor quality and can be burned most economically in AFB's. AFB use in the US would emphasize SO/sub 2/ removal in the combustion chamber to comply with air-pollution standards. While Chinese AFB's are simple, locally produced, US AFB's concentrate on sophisticated control systems to minimize reagent consumption in SO/sub 2/ capture. Various standard units and homemade AFB boilers in China are surveyed. Pictures of coal dumping, feeding, ash quenching, and control room are given. The Chinese procedure for startup is described in detail.

  19. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume VII. FBC Data-Base-Management System (FBC-DBMS) users manual

    SciTech Connect

    Louis, J.F.; Tung, S.E.

    1980-10-01

    The primary goal of the Fluidized Bed Combustor Data Base (FBCDB) is to establish a data repository for the express use of designers and research personnel involved in FBC development. FBCDB is implemented on MIT's 370/168 computer, using the Model 204 Data Base Management System (DBMS) developed by Computer Corporation of America. DBMS is a software that provides an efficient way of storing, retrieving, updating and manipulating data using an English-like query language. The primary content of FBCDB is a collection of data points defined by the value of a number of specific FBC variables. A user may interactively access the data base from a computer terminal at any location, retrieve, examine, and manipulate the data as well as produce tables or graphs of the results. More than 20 program segments are currently available in M204 User Language to simplify the user interface for the FBC design or research personnel. However, there are still many complex and advanced retrieving as well as applications programs to be written for this purpose. Although there are currently 71 entries, and about 2000 groups reposited in the system, this size of data is only an intermediate portion of our selection. The usefulness of the system at the present time is, therefore, limited. This version of FBCDB will be released on a limited scale to obtain review and comments. The document is intended as a reference guide to the use of FBCDB. It has been structured to introduce the user to the basics of FBCDB, summarize what the available segments in FBCDB can do, and give detailed information on the operation of FBCDB. This document represents a preliminary draft of a Users Manual. The draft will be updated when the data base system becomes fully implemented. Any suggestions as to how this manual may be improved will be appreciated.

  20. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume VI. FBC-Data Base-Management-System (FBC-DBMS) development

    SciTech Connect

    Louis, J.F.; Tung, S.E.

    1980-10-01

    The primary goal of the Fluidized Bed Combustor Data Base, (FBCDB), situated in MIT's Energy laboratory, is to establish a data repository for the express use of designers and research personnel involved in FBC development. DBMS is a software that provides an efficient way of storing, retrieving, updating and manipulating data using an English-like query language. It is anticipated that the FBCDB would play an active and a direct role in the development of FBC technology as well as in the FBC commercial application. After some in-house experience and after a careful and extensive review of commercially available database systems, it was determined that the Model 204 DBMS by Computer Corporation of America was the most suitable to our needs. The setup of a prototype in-house database also allowed us to investigate and understand fully the particular problems involved in coordinating FBC development with a DBMS. Various difficult aspects were encountered and solutions had been sought. For instance, we found that it was necessary to rename the variables to avoid repetition as well as to increase usefulness of our database and, hence, we had designed a classification system for which variables were classified under category to achieve standardization of variable names. The primary content of FBCDB is a collection of data points defined by the value of a number of specific FBC variables. A user may interactively access the database from a computer terminal at any location, retrieve, examine, and manipulate the data as well as produce tables or graphs of the results.

  1. Measuring and modeling solids movement in a large, cold fluidized-bed test facility. Fifth quarterly report for the period October 1, 1980-December 31, 1980

    SciTech Connect

    Fitzgerald, T. J.; Mrazek, R. V.; Crane, S. D.

    1980-12-01

    One part representing work on the development and testing of a flowmeter for measuring the motion of solids in a fluidized bed and the second part (a Ph. D. Thesis) on the plume model of fluidized-bed combustion of coal, including its development and validation, have been entered individually into EDB and ERA. (LTN)

  2. An equilibrium analysis to determine the speciation of trace elements in the flue gas from a coal-fired fluidized-bed boiler

    SciTech Connect

    Yan, R.; Gauthier, D.; Flamant, G.; Gautrin, M.

    1999-07-01

    Knowledge of the speciation of trace elements in flue gases from coal combustion is important for describing their partitioning between gaseous and condensed phases generated during combustion, for predicting their releases from a burning coal particle, and for choosing suitable sorbents to decrease the emission of trace elements. An equilibrium analysis has been carried out to determine in detail the speciation of Hg, Se and As, which are reported to be the most volatile trace elements in the flue gas from coal combustion, depending on the temperature (400--1,800 K) and the atmosphere (reducing or oxidizing conditions). The principle of minimizing the Gibbs free energy of the system is applied to predict the partitioning of these elements, using the thermodynamic equilibrium computer code SOLGASMIX coupled with the GFEDBASE database. The chlorine content in the system affects greatly the stable forms, and the relative affinities of the three elements to chlorine are in the order: Se {gt} As {gt} Hg under oxidizing conditions at both high (1,100 K) and low (600 K) temperatures. The three elements co-existing system is considered in order to investigate the interactions between these elements, HgSe(g) and AsSe(g) are found to possibly exist as major species in the local CO-enriched zone in a boiler. The competitive reactions of the 3 considered elements to oxygen, hydrogen and chlorine are also discussed.

  3. 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.

  4. 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.

  5. Rivesville multicell fluidized-bed boiler. Annual technical progress report, July 1979-June 1980

    SciTech Connect

    Not Available

    1980-01-01

    Design, construction and test program of a 300,000 lb/hr steam generating capacity multicell fluidized bed bouler (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. This report presents information 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 educators and needles, air distributor, corrosion-erosion and sulfur capture; engineering studies to improve MFB performance and reliability.

  6. 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.

  7. 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.

  8. Effect of biomass-sulfur interaction on ash composition and agglomeration for the co-combustion of high-sulfur lignite coals and olive cake in a circulating fluidized bed combustor.

    PubMed

    Varol, Murat; Atimtay, Aysel T

    2015-12-01

    This study aimed to investigate the effect of biomass-sulfur interaction on ash composition and agglomeration for the co-combustion of high-sulfur lignite coals and olive cake in a circulating fluidized bed combustor. The tests included co-combustion of 50-50% by wt. mixtures of Bursa-Orhaneli lignite+olive cake and Denizli-Kale lignite+olive cake, with and without limestone addition. Ash samples were subjected to XRF, XRD and SEM/EDS analyses. While MgO was high in the bottom ash for Bursa-Orhaneli lignite and olive cake mixture, Al2O3 was high for Denizli-Kale lignite and olive cake mixture. Due to high Al2O3 content, Muscovite was the dominant phase in the bottom ash of Denizli Kale. CaO in the bottom ash has increased for both fuel mixtures due to limestone addition. K was in Arcanite phase in the co-combustion test of Bursa/Orhaneli lignite and olive cake, however, it mostly appeared in Potassium Calcium Sulfate phase with limestone addition. PMID:26407346

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Fluidization quality analyzer for fluidized beds

    DOEpatents

    Daw, C. Stuart (Knoxville, TN); Hawk, James A. (Oak Ridge, TN)

    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.

  15. 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.

  16. 138 Chemical Engineering Education FLUIDIZED BED

    E-print Network

    Hesketh, Robert

    138 Chemical Engineering Education FLUIDIZED BED POLYMER COATING EXPERIMENT ROBERT P. HESKETH, C,2] and is a highly visual experiment in chemical engineering pro- cesses and experimentation. In addition for the chemical engineering profession. The field encom- passes many technologies, ranging from polymerization

  17. 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.

  18. Reversed flow fluidized-bed combustion apparatus

    DOEpatents

    Shang, Jer-Yu (Fairfax, VA); Mei, Joseph S. (Morgantown, WV); Wilson, John S. (Morgantown, WV)

    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.

  19. 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.

  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, 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.

  1. 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.

  2. Clean coal reference plants: Atmospheric CFB. Topical report, Task 1

    SciTech Connect

    Rubow, L.N.; Harvey, L.E.; Buchanan, T.L.; Carpenter, R.G.; Hyre, M.R.; Zaharchuk, R.

    1992-06-01

    The Clean Coal Technology Demonstration Program is a government and industry cofunded technology development effort to demonstrate a new generation of innovative coal utilization processes in a series of full-scale facilities. The goal of the program is to provide the US energy marketplace with a number of advanced, more efficient and environmentally responsive coal-using technologies. The Morgantown Energy Technology Center (METC) has the responsibility for monitoring the CCT Projects within certain technology categories, which correspond to the center`s areas of technology development, including atmospheric fluidized bed combustion, pressurized fluidized bed combustion, integrated gasification combined cycle, mild gasification, and industrial applications. A measure of success in the CCT program will be the commercial acceptance of the new technologies being demonstrated. The dissemination of project information to potential users is being accomplished by producing a series of reference plant designs which will provide the users a basis for the selection of technologies applicable to their future energy requirements. As a part of DOE`s monitoring and evaluation of the CCT Projects, Gilbert/Commonwealth (G/C) has been contracted to assist in this effort by producing the design of a commercial size Reference Plant, utilizing technologies developed in the CCT Program. This report, the first in a series, describes the design of a 400 MW electric power plant, utilizing an atmospheric pressure, circulating fluidized bed combustor (ACFB) similar to the one which was demonstrated at Colorado-Ute`s Nucla station, funded in Round 1 of the CCT Program. The intent of the reference plant design effort was to portray a commercial power plant with attributes considered important to the utility industry. The logical choice for the ACFB combustor was Pyropower since they supplied the ACFB for the Nucla Project.

  3. ENVIRONMENTAL ASSESSMENT OF SOLID RESIDUES FROM FLUIDIZED-BED FUEL PROCESSING

    EPA Science Inventory

    The report gives results of the first 15 months of an environmental assessment of solid residues generated by fluidized-bed combustion (FBC) of coal and gasification of oil. Included are a literature search, chemical and physical residue characterization, laboratory leaching stud...

  4. ENVIRONMENTAL ASSESMENT OF SOLID RESIDUES FROM FLUIDIZED-BED FUEL PROCESSING

    EPA Science Inventory

    The report gives results of a 2-year study of the environmental assessment of solid residues generated by fluidized-bed combustion (FBC) of coal and gasification of oil. Included are a literature search, chemical and physical residue characterization, laboratory leaching studies,...

  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. Performance analysis of co-firing waste materials in an advanced pressurized fluidized-bed combustor

    SciTech Connect

    Bonk, D.L.; McDaniel, H.M.; DeLallo, M.R. Jr.; Zaharchuk, R.

    1995-07-01

    The co-firing of waste materials with coal in utility scale power plants has emerged as an effective approach to produce energy and manage municipal wastes. Leading this approach is the atmospheric fluidized-bed combustor (AFBC). It has demonstrated its commercial acceptance in the utility market as a reliable source of power by burning a variety of waste and alternative fuels. The application of pressurized fluidized-bed combustor (PFBC) technology, although relatively new, can provide significant enhancements to the efficient production of electricity while maintaining the waste management benefits of AFBC. A study was undertaken to investigate the technical and economical feasibility of co-firing a PFBC with coal and municipal and industrial wastes. Focus was placed on the production of electricity and the efficient disposal of wastes for application in central power station and distributed locations. Issues concerning waste material preparation and feed, PFBC operation, plant emissions, and regulations are addressed. The results and conclusions developed are generally applicable to current and advanced PFBC design concepts. Wastes considered for co-firing include municipal solid waste (MSW), sewage sludge, and industrial de-inking sludge. Conceptual designs of two power plants rated at 250 MWe and 150 MWe were developed. Heat and material balances were completed for each plant along with environmental issues. With the PFBC`s operation at high temperature and pressure, efforts were centered on defining feeding systems capable of operating at these conditions. Air emissions and solid wastes were characterized to assess the environmental performance comparing them to state and Federal regulations. This paper describes the results of this investigation, presents conclusions on the key issues, and provides recommendations for further evaluation.

  7. Effect of CaO on retention of S, Cl, Br, As, Mn, V, Cr, Ni, Cu, Zn, W and Pb in bottom ashes from fluidized-bed coal combustion power station.

    PubMed

    Barto?ová, Lucie; Klika, Zden?k

    2014-07-01

    This work was conducted to evaluate whether Ca-bearing additives used during coal combustion can also help with the retention of some other elements. This work was focused on the evaluation of bottom ashes collected during four full-scale combustion tests at an operating thermal fluidized-bed power station. Bottom ashes were preferred to fly ashes for the study to avoid interference from condensation processes usually occurring in the post-combustion zone. This work focused on the behaviors of S, Cl, Br, As, Mn, V, Cr, Ni, Cu, Zn, W, and Pb. Strong positive correlations with CaO content in bottom ashes were observed (for all four combustion tests) for S, As, Cl and Br (R=0.917-0.999). Strong inverse proportionality was calculated between the contents of Pb, Zn, Ni, Cr and Mn and CaO, so these elements showed association to materials other than Ca-bearing compounds (e.g., to aluminosilicates, organic matter, etc.). Somewhat unclear behaviors were observed for W, Cu, and V. Their correlation coefficients were evaluated as statistically "not significant", i.e., these elements were not thought to be significantly associated with CaO. It was also discovered that major enrichment of CaO in the finest bottom ash fractions could be advantageously used for simple separation of elements strongly associated with these fractions, mainly S and As, but also Cl or Br. Removal of 5% of the finest ash particles brings about a decrease in As concentration down to 77%-80% of its original bulk ash content, which can be conveniently used e.g., when high As content complicates further ash utilization. PMID:25079991

  8. Process Analysis of Lignite Circulating Fluidized Bed Boiler Coupled with Pyrolysis Topping

    NASA Astrophysics Data System (ADS)

    Wang, Baoqun; Dong, Li; Wang, Yin; Matsuzawa, Y.; Xu, Guangwen

    We developed a comprehensive process model in ASPEN Plus to simulate the energy and mass balances of a lignite-fueled atmospheric circulating fluidized bed (CFB) boiler integrated with coal predrying and pyrolysis topping. In this model, it is assumed that the heat from exhausted flue gas was employed for coal predrying, and the sensible heat derived from circulated bed material was used for the pyrolysis topping (endothermic process). The simulation was conducted with respectto the Yunnan Kaiyuan CFB boiler, and two representative lignite coals from Xiao Long Tan (XLT) and Xin Shao (XS) were considered. The result shows that the predrying of coal with the sensible heat of above 363 K from flue gas, the amount of coal consumed in the boiler can be reduced by 3.5% and 5.3% for XLT lignite and XS lignite, respectively. It was also found that integration of pyrolysis topping with the boiler increased the coal consumption of the boiler, and the extent of consumption-increase varies with the yields of tar and gas in the pyrolysis topping process. For agas yield of 5.2% and a tar yield of 5-6%, the consumption of XS lignite increased by about 20% comparing to that in the case without topping.

  9. Spectral methods applied to fluidized-bed combustors

    SciTech Connect

    Brown, R.C.; Raines, T.S.; Thiede, T.D.

    1995-11-01

    The goal of this research is to characterize coals and sorbents during the normal operation of an industrial-scale circulating fluidized bed (CFB) boiler. The method determines coal or sorbent properties based on the analysis of transient CO{sub 2} or SO{sub 2} emissions from the boiler. Fourier Transform Infrared (FTIR) spectroscopy is used to qualitatively and quantitatively analyze the gaseous products of combustion. Spectral analysis applied to the transient response of CO{sub 2} and SO{sub 2} resulting from introduction of a batch of coal or limestone into the boiler yields characteristic time constants from which combustion or sorbent models are developed. The method is non-intrusive and is performed under realistic combustion conditions. Results are presented from laboratory studies and power plant monitoring.

  10. A Feasibility Study on Low Temperature Thermochemical Treatments of Austenitic Stainless Steel in Fluidized Bed Furnace

    NASA Astrophysics Data System (ADS)

    Haruman, Esa; Sun, Yong; Triwiyanto, Askar; Manurung, Yupiter H. P.; Adesta, Erry Y.

    2011-04-01

    In this work, the feasibility of using an industrial fluidized bed furnace to perform low temperature thermochemical treatments of austenitic stainless steels has been studied, with the aim to produce expanded austenite layers with combined wear and corrosion resistance, similar to those achievable by plasma and gaseous processes. Several low temperature thermochemical treatments were studied, including nitriding, carburizing, combined nitridingcarburizing (hybrid treatment), and sequential carburizing and nitriding. The results demonstrate that it is feasible to produce expanded austenite layers on the investigated austenitic stainless steel by the fluidized bed heat treatment technique, thus widening the application window for the novel low temperature processes. The results also demonstrate that the fluidized bed furnace is the most effective for performing the hybrid treatment, which involves the simultaneous incorporation of nitrogen and carbon together into the surface region of the component in nitrogen and carbon containing atmospheres. Such hybrid treatment produces a thicker and harder layer than the other three processes investigated.

  11. 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.

  12. 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.

  13. Comminution of limestone during batch fluidized-bed calcination and sulfation

    SciTech Connect

    Scala, F.; Cammarota, A.; Chirone, R.; Salatino, P.

    1997-02-01

    Batchwise fluidized-bed calcination and sulfation of a limestone were done to investigate particle comminution phenomena and their relation with parallel occurrence of reactions. Operating conditions of the bed were those typical of atmospheric bubbling fluidized-bed combustors. A general framework of comminution phenomena is outlined, which includes different types of fragmentations as well as attrition by abrasion. Comminution processes were characterized by following the modifications of bed sorbent particle-size distribution and the elutriation rates of fines throughout conversion. Mutual interactions between comminution processes and the progress of chemical reactions are assessed.

  14. Hydrodynamic model of advanced pressurized fluidized bed combustion

    SciTech Connect

    Horio, Masayuki; Lei, H.W.

    1997-12-31

    A hydrodynamic model was developed for the advanced pressurized fluidized bed combustion (A-PFBC) process. The particular system investigated here is composed of a pressurized circulating fluidized bed (PCFB) for coal gasification/desulfurization and a PCFB for combustion with the gas-solid counter-current flow through the two PCFBs. One of the most important parameters may be the material seal height (MSH) in the downcomer connecting the gasifier/desulfurizer and the combustor, which is thought to strongly influence the safe and stable operation of the process. In this mode, MSH was determined according to the pressure balance between the gasifier/desulfurizer and the combustor. The solid flux in the lower dense region of the two PCFBs was estimated by considering the clustering suspension and core-annulus flow. The mean cluster size and voidage in the cluster phase were predicted by the cluster size model of Horio-Ito (1996). Solid flux of the gasifier and combustor was calculated based on mass balances of limestone, char and ash in the system. Based on this model, the whole pressure profile loop in the system was predicted, and the effects of operating conditions on MSH between the gasifier and the combustor were investigated. The feasibility of the A-PCFB system with PCFBs both for the gasifier/desulfurizer and for the combustor was successfully confirmed.

  15. Technology evaluation for a waste-fuel-based circulating fluidized-bed project

    SciTech Connect

    Kavidass, S.

    1994-12-31

    A comparative technology evaluation is made of competing technologies - pulverized coal (PC), stoker-fired and circulating fluidized-bed boilers - for firing high-ash waste coal. Operating experience from Ukraine and India indicates that PC-fired boilers burning high-ash waste coal can be repowered with circulating fluidized-bed (CFB) technology. This has been necessary due to poor boiler availability, equipment deterioration, ash content variation in the fuel, and increasingly stringent emissions regulations. Due to these considerations, CFB technology was selected for Ebensburg Power Company`s high-ash waste coal project. The 55 MW B&W CFB boiler at Ebensburg Power, Pennsylvania, USA has successfully fired high-ash waste coal since May 1991. Operating experience of the Ebensburg CFB boiler, including availability, maintenance, and emissions is discussed.

  16. 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 obtained for the heat transfer coefficient.

  17. 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.

  18. 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.

  19. Solar heated fluidized bed gasification system

    NASA Astrophysics Data System (ADS)

    Qader, S. A.

    1981-09-01

    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.

  20. 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.

  1. 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.

  2. Predicting apparent Sherwood numbers for fluidized beds

    SciTech Connect

    Groenewold, H.; Tsotsas, E.

    1999-09-01

    Mass transfer data of bubbling fluidized beds have been reevaluated with a new model which is completely predictive. The model is based on a two-phase approach with active bypass, formally plug flow for the suspension gas and a consideration of backmixing in the main kinetic coefficient, i.e. in the apparent particle-to-fluid Sherwood number. A good agreement with experimental results of various authors with a broad range of Reynolds numbers and particle diameters is demonstrated.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. REGENERATION OF CALCIUM-BASED SO2 SORBENTS FOR FLUIDIZED-BED COMBUSTION: ENGINEERING EVALUATION

    EPA Science Inventory

    The report gives results of an engineering evaluation of regeneration of calcium-based SO2 sorbents (limestone and dolomite) for application in both atmospheric and pressurized fluidized-bed combustion (FBC) processes. Economics of FBC power plants, operated with regeneration, ar...

  9. ALTERNATIVES TO CALCIUM-BASED SO2 SORBENTS FOR FLUIDIZED-BED COMBUSTION: CONCEPTUAL EVALUATION

    EPA Science Inventory

    The report gives results of a conceptual engineering evaluation to screen supported metal oxides as alternatives to natural calcium-based sorbents (limestones and dolomites) for SO2 control in atmospheric and pressurized fluidized-bed combustion (FBC) processes. Alternative sorbe...

  10. Exergy method of power plant systems analysis and its application to a pressurized fluidized bed coal-fired combined-cycle power plant

    SciTech Connect

    Ghamarian, A.

    1981-01-01

    This thesis surveys the concepts of exergy and extends the exergy method of analysis from the standpoint of its applications to the power plant systems. After a brief historical review of exergy concepts, the general exergy equation is derived from the combined equation of First and Second Law, and it is shown that any special case of exergy equation is a simplified form of the general exergy equation. The mathematical method for the exergy analysis of a steady-state, steady-flow system, analogous to that of the First Law, is given. The exergy losses in a power plant are discussed. Then in order to examine these losses, the Second Law performance of major processes of combustion, compression, heat transfer, mixing and throttling have been analyzed analytically, and the exergy efficiencies are defined that accurately assess the thermodynamic performance of the corresponding processes. The methods for computation of exergy loss and exergy efficiency are given and simplified for practical cases of the corresponding processes. Analytical methods for evaluating the exergy of coal, pure substances (air and water), and combustion gases are presented and the energy-exergy tables for corresponding working substances are constructed. Finally, a comprehensive thermodynamic analysis, with emphasis on the Second Law (exergy) consideration, of an actual coal-fired, combined-cycle (CFCC) power plant, being designed by the General Electric Company, is carried out and suggestions are made as to what (and where), if any, improvement might be made in the design.

  11. 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 concentration. Opportunities for improvement with the fluidized bed include improving reproducibility among replicates, increasing mass recovery, improving the lid gasket seal.

  12. Experimental study and modelling of char combustion under fluidized bed conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Yongzhe; Xu, Xiangdong; Wirsum, Manfred C.; Hamel, Stefan; Fett, Franz N.

    1998-12-01

    The combustion behavior of chars from two Chinese coals has been investigated in a laboratory scale bubbling fluidized bed system in Siegen University, Germany. Experimental equipment and method are introduced. The ‘shrinking-core’ model and the ‘shrinking-particle’ model were employed to evaluate the kinetic parameters. The results indicated that the char conversion process of these two coals can be well described by the two models.

  13. 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).

  14. Engineering support services for the DOE/GRI coal-gasification research program. Evaluation of the data base for single-stage gasification of peat. [IGT 6 inch, single stage, fluidized bed (not PEATGAS)

    SciTech Connect

    Bostwick, L.E.; Hubbard, D.A.; Shah, K.V.; Do, L.T.

    1982-03-01

    Kellogg has reviewed the data base generated by IGT in the 6 inch PDU for the single stage fluidized bed gasification of peat. Kellogg's central finding is that the existing data base should be expanded by further testing in the PDU, after necessary modifications, to investigate further the effects of operating parameters within the ranges of interest. The existing data base consists of 20 PDU runs. Kellogg has concentrated on the Minnesota peat data base, since an insufficient number of runs exist for Maine and North Carolina peats to establish any valid trends. Consequently, the evaluation presented concerns only the Minnesota peat data base with respect to ranges of operating parameters studied, the criteria for good fluidized-bed operation and the effects of the key operating parameters on the performance. In Kellogg's opinion the existing data base demonstrates that: gasification of peat at 90+% carbon conversion is possible in a single stage fluidized bed reactor; the most significant operating parameters have been identified; the single stage fluidized bed peat gasifier has merit because of simplicity of operation, near-zero production of liquids and potential of operation without steam and at low pressure. However, Kellogg notes the following shortcomings:relatively small number of experimental runs and lack of data at certain levels of operating parameters studied; sintering occurred in 35% of the runs; in all the 20 test runs, fines losses exceeded in 5% of the feed and for the Minnesota peat data base, fines losses averaged 12.8%; use of large amounts of fluidizing gas (in this case N/sub 2/), which does not reflect commercial operation; and lack of data with higher peat feed moisture content. Thus, in Kellogg's opinion, considerable advantage is to be gained by expanding the existing data base and lists its specific recommendations.

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

    DOEpatents

    Cole, Rossa W. (E. Rutherford, NJ); Zoll, August H. (Cedar Grove, NJ)

    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.

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

    SciTech Connect

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

    1994-10-01

    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.

  17. Specification considerations for a circulating fluidized bed boiler

    SciTech Connect

    Liu, E.H.; Surabian, M. )

    1988-01-01

    The circulating fluidized bed (CFB) boiler is gradually gaining acceptance in both the industrial and utility sectors for electric power generation. Boiler steaming capacity in CFBs has increased to over a million pounds per hour in the most recent units. Many CFB units commisioned during the last few years worldwide have had difficult and extended start-up periods, but this experience has provided a good base of feedback for future units. There has been widespread use of the same criteria for a conventional pulverized coal or stoker boiler to specify the CFB boiler. This paper examines the unique design aspects of a CFB boiler and provides suggestions in the areas where specific requirements should be included in the specification of the boiler and its related systems. Areas examined include fuel handling area, burner systems, the combustor, cyclone and solids recirculation equipment, convention pass, the design and installation of refractories, fans and blowers, bed ash removal system, and particulate control equipment.

  18. 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.

  19. The Nucla Circulating Fluidized-Bed Demonstration Project: A U.S. DOE post-project assessment

    SciTech Connect

    1995-06-01

    This report is a post-project assessment of the Nucla Circulating Fluidized-Bed (CFB) Demonstration Project, the second project to be completed in the DOE Clean Coal Technology Program. Nucla was the first successful utility repowering project in the US, increasing the capacity of the original power station from 36 MW(e) to 110 MW(e) and extending its life by 30 years. In the CFB boiler, combustion and desulfurization both take place in the fluidized bed. Calcium in the sorbent captures sulfur dioxide and the relatively low combustion temperatures limit NOx formation. Hot cyclones separate the larger particles from the gas and recirculates them to the lower zones of the combustion chambers. This continuous circulation of coal char and sorbent particles is the novel feature of CFB technology. This demonstration project significantly advanced the environmental, operational, and economic potential of atmospheric CFB technology, precipitating a large number of orders for atmospheric CFB equipment. By 1994, more than 200 atmospheric CFB boilers have been constructed worldwide. Although at least six CFB units have been operated, the Nucla project`s CFB database continues to be an important and unique resource for the design of yet larger atmospheric CFB systems. The post-project assessment report is an independent DOE appraisal of the success a completed project had in achieving its objectives and aiding in the commercialization of the demonstrated technology. The report also provides an assessment of the expected technical, environmental, and economic performance of the commercial version of the technology as well as an analysis of the commercial market.

  20. Pyrolysis reactor and fluidized bed combustion chamber

    DOEpatents

    Green, Norman W. (Upland, CA)

    1981-01-06

    A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

  1. 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.

  2. Gas fluidized-bed stirred media mill

    DOEpatents

    Sadler, III, Leon Y. (Tuscaloosa, AL)

    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.

  3. Fluidized bed pyrolysis to gases containing olefins

    SciTech Connect

    Kuester, J.L.

    1980-01-01

    Recent gasification data are presented for a system designed to produce liquid hydrocarbon fuel from various biomass feedstocks. The factors under investigation were feedstock type, fluidizing gas type, residence time, temperature and catalyst usage. The response was gas phase composition. A fluidized bed system was utilized with a separate regenerator-combustor. An olefin content as high as 39 mole % was achieved. Hydrogen/carbon monoxide ratios were easily manipulated via steam addition over a broad range with an autocatalytic effect apparent for most feedstocks.

  4. 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.

  5. Combined fluidized bed retort and combustor

    DOEpatents

    Shang, Jer-Yu (Fairfax, VA); Notestein, John E. (Morgantown, WV); Mei, Joseph S. (Morgantown, WV); Zeng, Li-Wen (Morgantown, WV)

    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.

  6. Packed fluidized bed blanket for fusion reactor

    DOEpatents

    Chi, John W. H. (Mt. Lebanon, PA)

    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.

  7. Pressure Fluctuations as a Diagnostic Tool for Fluidized Beds

    SciTech Connect

    Joel R. Schroeder; Robert C. Brown

    1998-04-23

    The purpose of this project is to investigate the origin of pressure fluctuations in fluidized bed systems. The study will asses the potential for using pressure fluctuations as an indicator of fluidized bed hydrodynamics in both laboratory scale cold-models and industrial scale boilers.

  8. Pressure Fluctuations as a Diagnostic Tool for Fluidized Beds

    SciTech Connect

    Ethan Bure; Joel R. Schroeder; Ramon De La Cruz; Robert C. Brown

    1998-05-01

    The purpose of this project was to investigate the origin of pressure fluctuations in fluidized bed systems. The study assessed the potential for using pressure fluctuations as an indicator of fluidized bed hydrodynamics in both laboratory scale cold-models and industrial scale boilers. Both bubbling fluidized beds and circulating fluidized beds were evaluated. Testing including both cold-flow models and laboratory and industrial-scale combustors operating at elevated temperatures. The study yielded several conclusions on the relationship of pressure fluctuations and hydrodynamic behavior in fluidized beds. The study revealed the importance of collecting sufficiently long data sets to capture low frequency (on the order of 1 Hz) pressure phenomena in fluidized beds. Past research has tended toward truncated data sets collected with high frequency response transducers, which miss much of the spectral structure of fluidized bed hydrodynamics. As a result, many previous studies have drawn conclusions concerning hydrodynamic similitude between model and prototype fluidized beds that is insupportable from the low resolution data presented.

  9. 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.

  10. 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....

  11. 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....

  12. 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....

  13. 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....

  14. 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....

  15. Fluidization, combustion and emission behavior of biomass in fluidized bed combustion units

    SciTech Connect

    Kaeferstein, P.; Tepper, H.; Gohla, M.; Reimer, H.

    1997-12-31

    Gaseous components were measured over the height and the cross section inside a circulating fluidized bed riser with a thermal power of 60 kW. The combustion behavior of lignite (German brown coal), hard coal, biomass (China reed), and sewage sludge was investigated. The burn-out behavior was investigated by in-situ and real time measurement of the oxygen consumption using solid electrolyte sensor probes within a bubbling fluidized bed combustor with 15 kW thermal power. Non-uniform oxygen concentration profiles were found over the small riser cross-section which differed for the various fuels. The feed location and the fuel distribution also influences the horizontal oxygen profile. The reasons for the non-uniformity of the horizontal oxygen concentration profile are the combustion of volatile matter and the recirculation of char near the walls. A simulation model was developed to calculate the hydrodynamics and the oxygen consumption for the difference fuels inside the CFBC riser.

  16. Electrically enhanced fluidized bed heat exchanger

    SciTech Connect

    Lessor, D.L.; Robertus, R.J.; Roberts, G.L.

    1994-05-01

    The experiments have shown that a high level of electrical charging can be achieved in a fluidized bed of two resistive particle types; that bed stabilization rather than increased sensible heat transport dominates low frequency electric field effects on heat transfer with most bed loadings; and, hence, that applying an oscillatory potential difference between tubes or rods in a fluidized bed of two mutual contact-charging particle species gives reduced rather than improved heat transfer. Applying an oscillatory potential difference between rods in a bed of quartz particles fluidized alone did give improved heat transfer, however. With no electric field applied, most fluidized mixes were found to give higher heat transfer rates than the average of the values when each of the two species was fluidized alone. The high level of charging observed in some mixed beds may prove of interest for some air cleanup applications; the results show that simultaneous fluidization of pairs of bipolar charging materials of similar particle size is possible without excessive agglomeration. This would be important for air cleanup.

  17. Zevenhoven & Kilpinen NITROGEN 13.4.2002 4-34 4.11 Chemistry of nitrogen oxides at atmospheric fluidized bed

    E-print Network

    Laughlin, Robert B.

    Zevenhoven & Kilpinen NITROGEN 13.4.2002 4-34 4.11 Chemistry of nitrogen oxides at atmospheric of thermal NO is negligible, and almost all of the nitric oxide originates from fuel nitrogen. In circulating in the furnace increases even more. Describing the formation and decomposition of nitrogen oxides in fluidized

  18. Zevenhoven & Kilpinen NITROGEN 18.1.2004 4-35 4.11 Chemistry of nitrogen oxides at atmospheric fluidized bed

    E-print Network

    Zevenhoven, Ron

    Zevenhoven & Kilpinen NITROGEN 18.1.2004 4-35 4.11 Chemistry of nitrogen oxides at atmospheric of thermal NO is negligible, and almost all of the nitric oxide originates from fuel nitrogen. In circulating in the furnace increases even more. Describing the formation and decomposition of nitrogen oxides in fluidized

  19. Research of integral parameters for furnaces of a circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Gil, Andrey V.; Gil, Alexandra Y.

    2015-01-01

    Modern society poses several energy problems. Improving the efficiency and reliability of power equipment and reduce the impact on the environment. The paper presents the promising technology of superheated steam using different coals. The model of the furnace with a circulating fluidized bed and numerical simulation results of gas dynamic processes using application FIRE 3D. The analysis of aerodynamics and the distribution of the dispersed phase adjustment of the furnace.

  20. Heat transfer in freeboard region of fluidized beds

    SciTech Connect

    Biyikli, S.; Tuzla, K.; Chen, J.C.

    1983-10-01

    This research involved the study of heat transfer and fluid mechanic characteristics around a horizontal tube in the freeboard region of fluidized beds. Heat transfer coefficients were experimetnally measured for different bed temperatures, particle sizes, gas flow rates, and tube elevations in the freeboard region of air fluidized beds at atmospheric pressure. Local heat transfer coefficients were found to vary significantly with angular position around the tube. Average heat transfer coefficients were found to decrease with increasing freeboard tube elevation and approach the values for gas convection plus radiation for any given gas velocity. For a fixed tube elevation, heat transfer coefficients generally increased with increasing gas velocity and with high particle entrainment they can approach the magnitudes found for immersed tubes. Heat transfer coefficients were also found to increase with increasing bed temperature. It was concluded that this increase is partly due to increase of radiative heat transfer and partly due to change of thermal properties of the fluidizing gas and particles. To investigate the fluid mechanic behavior of gas and particles around a freeboard tube, transient particle tube contacts were measured with a special capacitance probe in room temperature experiments. The results indicated that the tube surface experiences alternating dense and lean phase contacts. Quantitative information for local characteristics was obtained from the capacitance signals and used to develop a phenomenological model for prediction of the heat transfer coefficients around freeboard tubes. The packet renewal theory was modified to account for the dense phase heat transfer and a new model was suggested for the lean phase heat transfer. Finally, an empirical freeboard heat transfer correlation was developed from functional analysis of the freeboard heat transfer data using nondimensional groups representing gas velocity and tube elevation.

  1. ENVIRONMENTAL ASSESSMENT: SOURCE TEST AND EVALUATION REPORT--EXXON MINIPLANT PRESSURIZED FLUIDIZED-BED COMBUSTOR WITH SORBENT REGENERATION

    EPA Science Inventory

    The report gives results of a comprehensive emission sampling and analysis of the EPA-sponsored, Exxon Miniplant, pressurized, coal-fired, fluidized-bed combustor (PFBC) and sorbent regeneration system. Air pollutant emissions of seven trace elements exceeded emissions goals in t...

  2. 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.

  3. Fluidized bed boiler having a segmented grate

    DOEpatents

    Waryasz, Richard E. (Longmeadow, MA)

    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.

  4. Wood gasification in a fluidized bed

    NASA Astrophysics Data System (ADS)

    Beck, S. R.; Wang, M. J.

    1980-04-01

    Gasification of oak sawdust in the Synthesis Gas From Manure (SGFM) pilot plant at Texas Tech University has been evaluated. The SGFM reactor operates as a countercurrent fluidized bed in which a biomass feedstock is fed to the top of the reactor and is fluidized by an air-steam mixture fed to the bottom of the reactor. Using oak sawdust from Missouri as the feedstock, the gas yields were 1.1 to 1.4 L/g daf feed when the average reactor temperature was 600 to 800 C. The gas contained about 4% C2H4 and 11% CH4. The gross heating value of the gas exceeded 11.2 MJ/cu m in all cases. The gasification of wood is compared to previous results obtained for cattle manure. The differences are due to the relative amounts of cellulose, hemicellulose, and lignin in the feedstock.

  5. Solids feed nozzle for fluidized bed

    DOEpatents

    Zielinski, Edward A. (Harwinton, CT)

    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.

  6. 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.

  7. 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 height for both spherical and non-spherical particles. Further, it decrease with decreasing particle size and decreases with decreasing bed diameter. Shadow sizing, a non-intrusive imaging and diagnostic technology, was also used to visualize flow fields inside fluidized beds for both spherical and non- spherical particles and to detect the particle sizes.

  8. Alexandria fluidized-bed process development unit: cold-mode testing

    SciTech Connect

    1981-02-01

    The objectives of the current test program include: validation of predictions from the Massachusetts Institute of Technology (MIT) Coal Atmospheric Fluidized Bed Combustor System Model; experimental studies supporting AFBC process developments; and the collection of transient data for process control design. This topical report summarizes results from cold mode testing, i.e., experiments performed without combustion for MIT Model verification. During these tests, sulfated limestone (generated from normal AFBC operations) was fluidized with air at temperatures ranging from 80 to 500/sup 0/F in the 3' x 3' (nominal) size PDU at Alexandria, VA. The MIT Model predictions tested include: slumped bed height, minimum fluidization velocity, and expanded bed height. In all cases, there were large discrepancies between the Model predictions and corresponding experimental results. Other results obtained included solids size distribution and particle size profiles in the bed. Size distribution was adequately modeled by the Rosin-Rammler equation. No transient process data was collected due to hardware problems with the Data Acquisition System. Tests were also performed to determine the effect of maldistribution of air, caused by leaks in the air distributor, on experimental results. The data indicated that effects of these leaks seemed to be undetectable.

  9. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed. (a) Identification. An...

  10. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed. (a) Identification. An...

  11. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed. (a) Identification. An...

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

    DOEpatents

    Mehta, Gautam I. (Greensburg, PA); Rogers, Lynn M. (Export, PA)

    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.

  13. 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 sequestration of stack gas carbon dioxide gases for a 100% reduction in greenhouse gas emissions. The amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building block that offers all the advantages of coal gasification but in a more user friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. The PGM consists of a pressurized circulating fluidized bed (PCFB) reactor together with a recycle cyclone and a particulate removing barrier filter. Coal, air, steam, and possibly sand are fed to the bottom of the PCFB reactor and establish a relatively dense bed of coal/char in the bottom section. As these constituents react, a hot syngas is produced which conveys the solids residue vertically up through the reactor and into the recycle cyclone. Solids elutriated from the dense bed and contained in the syngas are collected in the cyclone and drain via a dipleg back to the dense bed at the bottom of the PCFB reactor. This recycle loop of hot solids acts as a thermal flywheel and promotes efficient solid-gas chemical reaction.

  14. 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)

  15. Proceedings of the 15th national conference on fluidized bed combustion

    SciTech Connect

    Reuther, R.B.

    1999-07-01

    Papers are arranged under the following topical sections: Computational and empirical studies of heat and mass transfer; Nitrogen oxides--Fundamentals and emissions; Environmental issues--Ash chemistry; Pressurized fluidized bed combustion (PFBC)--Filtration and hot gas cleanup issues; Atmospheric fluidized bed combustion (AFBC)--Operational experiences from commercial plants; Sulfur capture fundamentals; Opportunity fuels--Emissions and environmental issues; PFBC--Operational experiences; AFBC--Fuel studies; Opportunity fuels--Sewage sludge and municipal solid waste; PFBC--New developments; AFBC--Ash removal studies; Opportunity fuels--Biomass; PFBC--Bench-scale experiments; Environmental issues--Ash management and emissions; Ash fundamentals; Opportunity fuels--Emissions and environmental issues; PFBC--Component design and cost studies; AFBC--Design and operating experiences; Particle agglomeration and dispersion studies. 139 papers have been processed separately for inclusion on the data base.

  16. 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.

  17. 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.

  18. 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.

  19. SIMULTANEOUS CAPTURE OF METAL, SULFUR AND CHLORINE BY SORBENTS DURING FLUIDIZED BED INCINERATION. (R826694C697)

    EPA Science Inventory

    Metal capture experiments were carried out in an atmospheric fluidized bed incinerator to investigate the effect of sulfur and chlorine on metal capture efficiency and the potential for simultaneous capture of metal, sulfur and chlorine by sorbents. In addition to experimental...

  20. Prospects for using the technology of circulating fluidized bed for technically refitting Russian thermal power stations

    NASA Astrophysics Data System (ADS)

    Ryabov, G. A.; Folomeev, O. M.; Litun, D. S.; Sankin, D. A.; Dmitryukova, I. G.

    2009-01-01

    The present state and development of circulating fluidized bed (CFB) technology around the world are briefly reviewed. Questions of increasing the capacity of single boiler units and raising the parameters of steam are discussed. CFB boilers for 225- and 330-MW power units are described and their parameters are estimated as applied to the conditions of firing different Russian fuels. Indicators characterizing CFB boilers and pulverized-coal boilers are given. Capital outlays and operational costs for new coal-fired units are compared, and the results from this comparison are used to show the field of the most promising use of the CFB technology during technical refitting of Russian thermal power stations.

  1. 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.

  2. Fluidized bed pyrolysis of terrestrial biomass feedstocks

    SciTech Connect

    Besler, S.; Agblevor, F.A.; Davis, M.F.

    1994-12-31

    Hybrid poplar, switchgrass, and corn stover were pyrolyzed in a bench scale fluidized-bed reactor to examine the influence of storage time on thermochemical converting of these materials. The influence of storage on the thermochemical conversion of the biomass feedstocks was assessed based on pyrolysis product yields and chemical and instrumental analyses of the pyrolysis products. Although char and gas yields from corn stover feedstock were influenced by storage time, hybrid poplar and switchgrass were not significantly affected. Liquid, char, and gas yields were feedstock dependent. Total liquid yields (organic+water) varied from 58%-73% depending on the feedstock. Char yields varied from 14%-19% while gas yields ranged from 11%-15%. The chemical composition of the pyrolysis oils from hybrid polar feedstock was slightly changed by storage, however, corn stover and switchgrass feedstock showed no significant changes. Additionally, stored corn stover and hybrid poplar pyrolysis oils showed a significant decrease in their higher heating values compared to the fresh material.

  3. 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.

  4. An Investigation on Low-Temperature Thermochemical Treatments of Austenitic Stainless Steel in Fluidized Bed Furnace

    NASA Astrophysics Data System (ADS)

    Haruman, E.; Sun, Y.; Triwiyanto, A.; Manurung, Y. H. P.; Adesta, E. Y.

    2012-03-01

    In this study, the feasibility of using an industrial fluidized bed furnace to perform low-temperature thermochemical treatments of austenitic stainless steels has been studied, with the aim to produce expanded austenite layers with combined wear and corrosion resistance, similar to those achievable by plasma and gaseous processes. Several low-temperature thermochemical treatments were studied, including nitriding, carburizing, combined nitriding-carburizing (hybrid treatment), and sequential carburizing and nitriding. The results demonstrate that it is feasible to produce expanded austenite layers on the investigated austenitic stainless steel by the fluidized bed heat treatment technique, thus widening the application window for the novel low-temperature processes. The results also demonstrate that the fluidized bed furnace is the most effective for performing the hybrid treatment, which involves the simultaneous incorporation of nitrogen and carbon together into the surface region of the component in nitrogen- and carbon-containing atmospheres. Such hybrid treatment produces a thicker and harder layer than the other three processes investigated.

  5. 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.

  6. 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 sufficiently large that Brownian motion of the particles can be ignored and the Reynolds number sufficiently small that particle inertia is negligible. A packed particle bed is used to randomize and disperse the flowing fluid introduced by a peristaltic pump. The bed itself is a rectangular glass cell 8 cm wide (x), 0.8 cm deep and a height of 30.5 cm (z). The depth of field of the camera is approximately 0.5 cm so depth information is averaged. Over flow fluid is returned to the reservoir making a closed loop system. In these experiments the particles form a sediment approximately 5.7 cm high with the pump off and expand to 22 cm with the pump on. For the smaller particles the pump velocity is .5 millimeters per second and 1.1 millimeters per second for the large particles. At this concentration the bed has a very well defined top where particle concentration rapidly drops to zero.

  7. Filtration of fly ash using a fluidized-bed filter.

    PubMed

    Chiang, Bo-Chin; Wey, Ming-Yen; Liu, Kuang-Yu

    2005-02-01

    This study focuses on the control of particulates with a fluidized-bed filter in exhaust gas stream. The fluidized-bed filter classified in the granular bed filtration technology was employed to demonstrate the performance for removal of fly ash at indicated operating velocities, fixed bed heights, and bed temperatures; then the collecting mechanisms of particulates by fluidized-bed filter were studied. The size distribution of fly ash passing through the fluidized-bed filter was also analyzed. The results indicate that at higher operating velocities and fixed bed heights, the removal of fly ash is more efficient and inertial impaction is the main mechanism when the fluidized-bed is operated at room temperature (25 degrees C). While operating at higher temperatures (200 degrees C), efficiency of 93.2% to 99.4% can be achieved for submicron particles. It is supposed to be the diffusion mechanism that is responsible for collecting such small particles, and high temperature is a favorable condition because of diffusion. PMID:15796108

  8. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Yan Cao; John Smith

    2008-05-31

    On February 14, 2002, President Bush announced the Clear Skies Initiative, a legislative proposal to control the emissions of nitrogen oxides (NO{sub x}), sulfur dioxide (SO{sub 2}), and mercury from power plants. In response to this initiative, the National Energy Technology Laboratory organized a Combustion Technology University Alliance and hosted a Solid Fuel Combustion Technology Alliance Workshop. The workshop identified multi-pollutant control; improved sorbents and catalysts; mercury monitoring and capture; and improved understanding of the underlying reaction chemistry occurring during combustion as the most pressing research needs related to controlling environmental emissions from fossil-fueled power plants. The Environmental Control Technology Laboratory will help meet these challenges and offer solutions for problems associated with emissions from fossil-fueled power plants. The goal of this project was to develop the capability and technology database needed to support municipal, regional, and national electric power generating facilities to improve the efficiency of operation and solve operational and environmental problems. In order to effectively provide the scientific data and the methodologies required to address these issues, the project included the following aspects: (1) Establishing an Environmental Control Technology Laboratory using a laboratory-scale, simulated fluidized-bed combustion (FBC) system; (2) Designing, constructing, and operating a bench-scale (0.6 MW{sub th}), circulating fluidized-bed combustion (CFBC) system as the main component of the Environmental Control Technology Laboratory; (3) Developing a combustion technology for co-firing municipal solid waste (MSW), agricultural waste, and refuse-derived fuel (RDF) with high sulfur coals; (4) Developing a control strategy for gaseous emissions, including NO{sub x}, SO{sub 2}, organic compounds, and heavy metals; and (5) Developing new mercury capturing sorbents and new particulate filtration technologies. Major tasks during this period of the funded project's timeframe included: (1) Conducting pretests on a laboratory-scale simulated FBC system; (2) Completing detailed design of the bench-scale CFBC system; (3) Contracting potential bidders to fabricate of the component parts of CFBC system; (4) Assembling CFBC parts and integrating system; (5) Resolving problems identified during pretests; (6) Testing with available Powder River Basin (PRB) coal and co-firing of PRB coal with first wood pallet and then chicken wastes; and (7) Tuning of CFBC load. Following construction system and start-up of this 0.6 MW CFBC system, a variety of combustion tests using a wide range of fuels (high-sulfur coals, low-rank coals, MSW, agricultural waste, and RDF) under varying conditions were performed to analyze and monitor air pollutant emissions. Data for atmospheric pollutants and the methodologies required to reduce pollutant emissions were provided. Integration with a selective catalytic reduction (SCR) slipstream unit did mimic the effect of flue gas composition, including trace metals, on the performance of the SCR catalyst to be investigated. In addition, the following activities were also conducted: (1) Developed advanced mercury oxidant and adsorption additives; (2) Performed laboratory-scale tests on oxygen-fuel combustion and chemical looping combustion; and (3) Conducted statistical analysis of mercury emissions in a full-scale CFBC system.

  9. 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)

  10. 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.

  11. Material handling systems for the fluidized-bed combustion boiler at Rivesville, West Virginia

    NASA Technical Reports Server (NTRS)

    Branam, J. G.; Rosborough, W. W.

    1977-01-01

    The 300,000 lbs/hr steam capacity multicell fluidized-bed boiler (MFB) utilizes complex material handling systems. The material handling systems can be divided into the following areas: (1) coal preparation; transfer and delivery, (2) limestone handling system, (3) fly-ash removal and (4) bed material handling system. Each of the above systems are described in detail and some of the potential problem areas are discussed. A major potential problem that exists is the coal drying system. The coal dryer is designed to use 600 F preheated combustion air as drying medium and the dryer effluent is designed to enter a hot electrostatic precipitator (730 F) after passage through a cyclone. Other problem areas to be discussed include the steam generator coal and limestone feed system which may have operating difficulties with wet coal and/or coal fines.

  12. 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 sequestration of stack gas carbon dioxide gases for a 100% reduction in greenhouse gas emissions.

  13. An Analysis of the Use of Fluidized-Bed Heat Exchangers for Heat Recovery 

    E-print Network

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

    1980-01-01

    The principles of fluidized-bed operation and the factors affecting the performance of a fluidized-bed waste heat boiler (FBWHB) are discussed in detail. Factors included in the discussion are bed temperature and pressure, heat transfer coefficient...

  14. An investigation of particle mixing in a gas-fluidized bed

    NASA Technical Reports Server (NTRS)

    Carlson, R. E.; Gabor, J. D.

    1968-01-01

    Mechanism for particle movement in gas-fluidized beds was studied both from the theoretical and experimental points of view. In a two-dimensional fluidized bed particle trajectories were photographed when a bubble passed through.

  15. Fluidized bed combustion tested for Turkish oil shales

    SciTech Connect

    Not Available

    1986-09-01

    About 7.5 billion tons of lignite and 5 billion tons of oil shale deposits are potential energy sources and therefore potential air pollution sources for Turkey. The low calorific value, and high ash and sulfur contents of these fuels render fluidized bed combustion a promising method of utilization. A fluidized bed combustion system with a nominal capacity of 418,000 to 627,000 kilojoules per hour for producing hot water has been designed and constructed at Istanbul Technical University. This paper lists the important characteristics of the main Turkish lignite and oil shale reserves, and the specifications of the pilot-scale fluidized-bed combustor designed to burn these fuels.

  16. Methods of forming a fluidized bed of circulating particles

    DOEpatents

    Marshall, Douglas W. (Blackfoot, ID)

    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.

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

    SciTech Connect

    Rokkam, Ram

    2012-11-02

    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.

  18. 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)

  19. 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/).

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

    DOEpatents

    Talmud, Fred M. (Berkeley Heights, NJ); Garcia-Mallol, Juan-Antonio (Morristown, NJ)

    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.

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

    DOEpatents

    Yang, Ralph T. (Middle Island, NY); Steinberg, Meyer (Huntington Station, NY)

    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.

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

    DOEpatents

    Gamble, Robert L. (Wayne, NJ); Garcia-Mallol, Juan A. (Morristown, NJ)

    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.

  3. Development of wear resistant gas turbines downstream of a pressurized fluidized bed combustor

    NASA Astrophysics Data System (ADS)

    Rukes, B.

    1983-04-01

    The development of a wear resistant gas turbine, suitable for use in the aggressive gas atmosphere downstream of a pressurized fluidized bed combustor, is studied. The parameters which influence the wear characteristics of gas turbine blades in strongly erosive and corrosive gas atmospheres were investigated. Results show that it is possible, with a corresponding hot gas cleanup system, to construct a wear resistant gas turbine. A test program which includes heating tests, wear-test, and blade cooling tests is outlined. A design for a wear-test facility which permits the study of the combined erosion/corrosion attack on a rotating specimen-carrying disk is suggested.

  4. 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.

  5. Pressurized Fluidized Bed Combustion Second-Generation System Research and Development

    SciTech Connect

    A. Robertson; D. Horazak; R. Newby; H. Goldstein

    2002-11-01

    Research is being conducted under United States Department of Energy (DOE) Contract DE-AC21-86MC21023 to develop a new type of coal-fired plant for electric power generation. This new type of plant--called a Second-Generation or Advanced Pressurized Circulating Fluidized Bed Combustion (APCFB) plant--offers the promise of efficiencies greater than 45% (HHV), with both emissions and a cost of electricity that are significantly lower than conventional pulverized-coal-fired plants with scrubbers. The APCFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized bed boiler (PCFB), and the combustion of carbonizer syngas in a topping combustor to achieve gas turbine inlet temperatures of 2300 F and higher. A conceptual design was previously prepared for this new type of plant and an economic analysis presented, all based on the use of a Siemens Westinghouse W501F gas turbine with projected carbonizer, PCFB, and topping combustor performance data. Having tested these components at the pilot plant stage, the referenced conceptual design is being updated to reflect more accurate performance predictions together with the use of the more advanced Siemens Westinghouse W501G gas turbine and a conventional 2400 psig/1050 F/1050 F/2-1/2 in. steam turbine. This report describes the updated plant which is projected to have an HHV efficiency of 48% and identifies work completed for the October 2001 through September 2002 time period.

  6. Meat and bone meal as secondary fuel in fluidized bed combustion

    SciTech Connect

    L. Fryda; K. Panopoulos; P. Vourliotis; E. Kakaras; E. Pavlidou

    2007-07-01

    Meat and Bone Meal (MBM) was co-fired in a laboratory scale fluidized bed combustion (FBC) apparatus with two coals. Several fuel blends were combusted under different conditions to study how primary fuel substitution by MBM affects flue gas emissions as well as fluidized bed (FB) agglomeration tendency. MBM, being a highly volatile fuel, caused significant increase of CO emissions and secondary air should be used in industrial scale applications to conform to regulations. The high N-content of MBM is moderately reflected on the increase of nitrogen oxides emissions which are reduced by MBM derived volatiles. The MBM ash, mainly containing bone material rich in Ca, did not create any noteworthy desulphurization effect. The observed slight decrease in SO{sub 2} emissions is predominantly attributed to the lower sulphur content in the coal/MBM fuel mixtures. The SEM/EDS analysis of bed material samples from the coal/MBM tests revealed the formation of agglomerates of bed material debris and ash with sizes that do not greatly exceed the original bed inventory and thus not problematic. 37 refs., 9 figs., 3 tabs.

  7. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Yan Cao; John Smith

    2007-03-31

    This report is to present the progress made on the project entitled ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2007 through March 31, 2007. The effort in this quarter has concentrated on installing the CFBC Facility and for conducting cold fluidization operations tests in the CFBC facility. The assembly of the ash recirculation pipe duct from the cyclones back to the bed area of the combustor, including the upper and lower loop seals was completed. The electric bed pre-heater was installed to heat the fluidizing air as it enters the wind box. The induced draft fan along with its machine base and power supply was received and installed. The flue gas duct from secondary cyclone outlet to induced draft fan inlet was received and installed, as well as the induced fan flue gas discharge duct. Pressure testing from the forced draft fan to the outlet of the induced fan was completed. In related research a pilot-scale halogen addition test was conducted in the empty slipstream reactor (without (Selective Catalytic Reduction) SCR catalyst loading) and the SCR slipstream reactor with two commercial SCR catalysts. The greatest benefits of conducting slipstream tests can be flexible control and isolation of specific factors. This facility is currently used in full-scale utility and will be combined into 0.6MW CFBC in the future. This work attempts to first investigate performance of the SCR catalyst in the flue gas atmosphere when burning Powder River Basin (PRB), including the impact of PRB coal flue gas composition on the reduction of nitrogen oxides (NOx) and the oxidation of elemental mercury (Hg(0)) under SCR conditions. Secondly, the impacts of hydrogen halogens (Hydrogen fluoride (HF), Hydrogen chloride (HCl), Hydrogen Bromide (HBr) and Hydrogen Iodine (HI)) on Hg(0) oxidation and their mechanisms can be explored.

  8. Research on carbon content in fly ash from circulating fluidized bed boilers

    SciTech Connect

    Xianbin Xiao; Hairui Yang; Hai Zhang; Junfu Lu; Guangxi Yue

    2005-08-01

    The carbon content in the fly ash from most Chinese circulating fluidized bed (CFB) boilers is much higher than expected, which directly influences the combustion efficiency. In the present paper, carbon burnout was investigated in both field tests and laboratory experiments. The effect of coal property, operation condition, gas-solid mixing, char deactivation, residence time, and cyclone performance are analyzed seriatim based on a large amount of experimental results. A coal index is proposed to describe the coal rank, having a strong effect on the char burnout. Bad gas-solid mixing in the furnace is another important reason of the higher carbon content in the fly ash. Some chars in the fly ash are deactivated during combustion of large coal particles and have very low carbon reactivity. Several suggestions are made about design, operation, and modification to reduce the carbon content in the fly ash. 14 refs., 14 figs., 1 tab.

  9. Lagrangian Approach to Study Catalytic Fluidized Bed Reactors

    NASA Astrophysics Data System (ADS)

    Madi, Hossein; Hossein Madi Team; Marcelo Kaufman Rechulski Collaboration; Christian Ludwig Collaboration; Tilman Schildhauer Collaboration

    2013-03-01

    Lagrangian approach of fluidized bed reactors is a method, which simulates the movement of catalyst particles (caused by the fluidization) by changing the gas composition around them. Application of such an investigation is in the analysis of the state of catalysts and surface reactions under quasi-operando conditions. The hydrodynamics of catalyst particles within a fluidized bed reactor was studied to improve a Lagrangian approach. A fluidized bed methanation employed in the production of Synthetic Natural Gas from wood was chosen as the case study. The Lagrangian perspective was modified and improved to include different particle circulation patterns, which were investigated through this study. Experiments were designed to evaluate the concepts of the model. The results indicate that the setup is able to perform the designed experiments and a good agreement between the simulation and the experimental results were observed. It has been shown that fluidized bed reactors, as opposed to fixed beds, can be used to avoid the deactivation of the methanation catalyst due to carbon deposits. Carbon deposition on the catalysts tested with the Lagrangian approach was investigated by temperature programmed oxidation (TPO) analysis of ex-situ catalyst samples. This investigation was done to identify the effects of particles velocity and their circulation patterns on the amount and type of deposited carbon on the catalyst surface. Ecole Polytechnique Federale de Lausanne(EPFL), Paul Scherrer Institute (PSI)

  10. TREATMENT OF MUNICIPAL WASTEWATERS BY THE FLUIDIZED BED BIOREACTOR PROCESS

    EPA Science Inventory

    A 2-year, large-scale pilot investigation was conducted at the City of Newburgh Water Pollution Control Plant, Newburgh, NY, to demonstrate the application of the fluidized bed bioreactor process to the treatment of municipal wastewaters. The experimental effort investigated the ...

  11. LEVEL 2 CHEMICAL ANALYSIS OF FLUIDIZED-BED COMBUSTOR SAMPLES

    EPA Science Inventory

    The report gives results of a Level 1 data evaluation and prioritization and the Level 2 environmental assessment (EA) chemical data acquired on a set of fluidized-bed combustor (FBC) particulate samples. The Level 2 analysis followed the approach described in 'Approach to Level ...

  12. Heat exchanger support apparatus in a fluidized bed

    DOEpatents

    Lawton, Carl W. (West Hartford, CT)

    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.

  13. Energy/exergy analysis of pressurized fluidized bed combustor

    SciTech Connect

    Ghamerian, A.; Cambel, A.B.

    1982-08-01

    A combined-cycle pressurized fluidized bed combustor with steam turbine and gas turbine generating units is considered by invoking First (energy) and Second (exergy) analysis. Energy and exergy flow diagrams are presented. It is noted that exergy analysis provides insights that may be helpful in optimizing system components.

  14. Disposal of fluidized-bed combustion ash in an underground mine to control acid mine drainage and subsidence. Quarterly technical progress report, December 1994--February 1995

    SciTech Connect

    1995-03-01

    Research continued on the disposal of fluidized-bed combustion products in underground mines in order to control acid mine drainage and ground subsidence. This quarter, the installation of a coal ash grout into an underground mine void was accomplished. A mixture of 10% portland cement was added to the ash. Problems arose with the clumping of the grout.

  15. 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.

  16. Update of waste fuel firing experience in Foster Wheeler circulating fluidized bed boilers

    SciTech Connect

    Abdulally, I.F.; Reed, K.A.

    1993-12-31

    As the costs and availability of more conventional fuels continue to escalate, more and more customers are investigating and choosing operation with lower cost waste or alternative fuels. Details of units firing waste or alternative fuels which have been in active service for many years are summarized, and the fuel analyses are given. This chapter gives a general overview of the projects that are or will be firing waste or alternative fuels, namely, the Mt. Carmel Manitowoc, NISCO and HUNOSA units. The experience of the four operating units has demonstrated that waste and alternative fuels can be successfully and economically burned in an atmosphere circulating fluidized bed unit while meeting permitted emission requirements.

  17. Two-stage steam gasification of waste biomass in fluidized bed at low temperature: parametric investigations and performance optimization.

    PubMed

    Xiao, Xianbin; Meng, Xianliang; Le, Duc Dung; Takarada, Takayuki

    2011-01-01

    Steam gasification of waste biomass has been studied in a two-stage fluidized bed reactor, which has the primary pyrolysis fluidized bed using silica sand as bed material and the secondary reforming fixed bed with catalyst. The main objectives are parametric investigation and performance improvement especially at low temperature of around 600 °C using the wood chip and the pig manure compost as feedstock. Main operating variables studied are pyrolysis temperature, catalytic temperature, steam/biomass-C ratio, space velocity and different catalyst. Reaction temperatures and steam/C ratio have important role on the gasification process. About 60 vol.% H2 (dry and N2 free) and about 2.0 Nm3/kg biomass (dry and ash free basis) can be obtained under good conditions. Compared to Ni/Al2O3, Ni/BCC (Ni-loaded brown coal char) has a better ability and a hopeful prospect for the stability with coking resistance. PMID:20889337

  18. 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.

  19. Use of fluidized bed combustion by-products for liners and alkali substitutes. Technical report, March 1--May 31, 1995

    SciTech Connect

    Paul, B.C.; Esling, S.; Pisani, F.; Wells, T.

    1995-12-31

    Fluidized Bed Combustion of coal eliminates most emissions of S and N oxides but produces sizable volumes of a solid residue that EPA may require to be placed in capped and lined landfills. Fluidized Bed Combustors are one of the most promising growth markets for Illinois coal and imposing cap and liner requirements may make the technology uneconomic. Fluidized Bed residues are cementlike and when mixed with soil, produce a material as impermeable as the clay liners used at landfills. This project will demonstrate that the residues can be mixed with soils by regular construction equipment and used in place of clays as liner material. The demonstration cap will cover an area of 7 acres and will prevent water infiltration into acid producing material. Baseline studies of Briar Creek indicate that the water is now highly degraded by acid drainage. Construction delays have enhanced the data collected on Briar Creek by allowing monitoring to continue through major seasonal changes without any effects attributable to the FBC ash. Materials needed to place the wells and lysimeters have been obtained. A contractor will build and deliver a mobile foam generator and spray to the field to demonstrate fugitive dust control from FBC fly ash (dust problem is one key barrier to more widespread use of FBC ash).

  20. Process for generating electricity in a pressurized fluidized-bed combustor system

    DOEpatents

    Kasper, Stanley (Pittsburgh, PA)

    1991-01-01

    A process and apparatus for generating electricity using a gas turbine as part of a pressurized fluidized-bed combustor system wherein coal is fed as a fuel in a slurry in which other constituents, including a sulfur sorbent such as limestone, are added. The coal is combusted with air in a pressurized combustion chamber wherein most of the residual sulfur in the coal is captured by the sulfur sorbent. After particulates are removed from the flue gas, the gas expands in a turbine, thereby generating electric power. The spent flue gas is cooled by heat exchange with system combustion air and/or system liquid streams, and the condensate is returned to the feed slurry.

  1. Experiment and grey relational analysis of CWS spheres combustion in a fluidized bed

    SciTech Connect

    Hui Wang; Xiumin Jiang; Jianguo Liu; Weigang Lin

    2007-08-15

    In order to study the combustion of coal water slurry (CWS) in fluidized bed boilers, artificial CWS droplet spheres were used for simulation of the spheres formed from CWS droplets which fall from the furnace top to the bed. The artificial spheres were introduced to a bench-scale fluidized bed furnace. Quartz sand was used as the bed material. The influence of the operation conditions (e.g., bed temperature, superficial gas velocity, and bed height) on the combustion characteristics was investigated. The bed temperatures were varied at 650, 750, 850, and 950{sup o}C. The gas velocities were in a range of fluidization numbers W (defined as U/U{sub mf}) of 3, 3.5, 4, and 4.5. The bed heights were varied 30, 50, 70, and 90 mm. The CWS spheres were taken out at five residence times (15, 30, 45, 60, and 75 s). The mass ratio of the residue fixed carbon to parent fixed carbon was calculated for studying the influential factors. Under the reference conditions, it is shown that the burnout time is less than 150 s. The grey relational analysis was used to study the degree of relative importance of the influential factors. The results showed that the influence of the bed height is the least, the fluidization number has the greatest influence in the early and later stages, and the bed temperature contributes most in the intermediate stages. 16 refs., 16 figs., 6 tabs.

  2. 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 yielded the lowest tar concentration (1.6 g/Nm 3). High-temperature and low-pressure conditions achieved the highest carbon conversion and cold gas efficiencies of 91 and 94%, respectively. In addition, a relatively new method for monitoring hydrodynamic conditions in fluidized bed reactors using high-frequency bed pressure fluctuation measurement was demonstrated. This method proved capable of being used as a fluidized bed diagnostic method under reactive conditions.

  3. Experimental study on the dynamics of gas-fluidized beds.

    PubMed

    Valverde, J M; Quintanilla, M A S; Castellanos, A; Mills, P

    2003-01-01

    Gas-fluidized fine powders display three regimes of fluidization: solidlike, fluidlike, and bubbling. We investigate, from both macroscopic and local measurements, the transition between these regimes. We show that the transition between the solidlike and the fluidlike regimes takes place along an interval of gas velocities in which transient active regions alternate with transient solid networks. Although in the apparently homogeneous fluidlike regime large amplitude bubbles are not perceived and the bed expands continuously with increasing gas flow, optical probe local measurements show the existence of mesoscale pseudoturbulent structures and short-lived voids, reminiscent of liquid-fluidized beds behavior, and whose characteristic temporal frequency increases with gas velocity. These mesostructures might be responsible for the fast diffusion measured in gas-fluidized beds. PMID:12636598

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

    DOEpatents

    DeFeo, Angelo (Totowa, NJ); Hosek, William S. (Mt. Tabor, NJ)

    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.

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

    DOEpatents

    DeFeo, Angelo (Totowa, NJ); Hosek, William (Mt. Tabor, NJ)

    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.

  6. 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. PMID:22055091

  7. A Hydrodynamic Characteristic of a Dual Fluidized Bed Gasification

    NASA Astrophysics Data System (ADS)

    Sung, Yeon Kyung; Song, Jae Hun; Bang, Byung Ryeul; Yu, Tae U.; Lee, Uen Do

    A cold model dual fluidized bed (DFB) reactor, consisting of two parallel interconnected bubbling and fast fluidized beds, was designed for developing an auto-thermal biomass gasifier. The combustor of this system burns the rest char of the gasification process and provides heat to the gasifier by circulating solids inventory. To find an optimal mixing and circulation of heavy solid inventory and light biomass and char materials, we investigate two types of DFB reactors which have different configuration of distributor and way-out location of the solid inventory and char materials in the gasifier. To determine appropriate operating conditions, we measured minimum fluidization velocity, solid circulation rate, axial solid holdup and gas bypassing between the lower loop seal and the gasifier.

  8. Desulfurization Characteristics of Fly Ash Recirculation and Combustion in the Circulating Fluidized Bed Boiler

    NASA Astrophysics Data System (ADS)

    Li, S. F.; Fang, M. X.; Yu, B.; Wang, Q. H.; Luo, Z. Y.

    The experiments of the fly ash recycle combustion using Guizhou anthracite were carried out in a bench scale circulating fluidized bed (CFB) combustor. Effects of some key operating parameters such as recycle ash to coal mass ratio (Ca to S molar ratio), temperature, reactivation modeof fly ash, circulation rateand fluidization velocity on the desulfurization efficiency were intensively investigated. It is shown that thelimestone utilization efficiency could be improved about 30% with the following operating conditions: the mass ratio of fly ash (reactivated by water and dried at 90°C) to coal was 0.45, the furnace temperature was 880°C, the water to ash mass ratio was 4.5% (the water-to-calcium molar ratio was 0.55) and circulation rate was 18.

  9. The Hopkins repowering project a utility scale circulating fluidized bed boiler

    SciTech Connect

    Brinkworth, G.S. ); Hobday, J.M. ); Mazur, K.S. ); Goldich, S.J. ); Sturdevant, B.L. and Associates, Denver, CO )

    1991-01-01

    The existing boiler at the City of Tallahassee's 250 MW Hopkins Station Unit 2 fires natural gas and No. 6 fuel oil. In November 1990, the City and the U.S. Department of Energy (DOE) signed an agreement to repower the existing Unit 2 with a single circulating fluidized bed (CFB) boiler, as part of DOE's Clean Coal Technology Program. The CFB boiler, which will be fired with Eastern Bituminous coal, will be approximately twice the capacity of currently operating CFB boilers. This paper outlines objectives of the project and its participants. It will highlight significant technological and environmental issues and addresses the following subjects. Historical perspective of the project; The project organization; Project scope, schedule and cost; and Permitting and environmental issues.

  10. Bed agglomeration characteristics of rice straw combustion in a vortexing fluidized-bed combustor.

    PubMed

    Duan, Feng; Chyang, Chien-Song; Zhang, Li-hui; Yin, Siang-Fong

    2015-05-01

    To investigate bed agglomeration characteristics, the combustion of pelletized rice straw was conducted in a bench-scale vortexing fluidized bed. Effects of bed temperature, superficial velocity, secondary gas velocities, and mass blended ratio of coal on the defluidization time were investigated. The alkali concentrations in different sections of the bed zone were also studied. The bed materials and agglomerates were analyzed using SEM/EDX to obtain the surface morphology and the compositions. The results revealed that the defluidization time is increased with superficial gas velocity and is decreased with bed temperature. Eutectic composition with low melting point materials promote defluidization at high temperatures. Effect of the secondary gas velocity on the defluidization time indicates different trends at different bed temperatures. The highest value of alkali concentration appears at upper bubbling zone. Coal ash can avoid the existence of a certain eutectic composition, and increases its melting point. PMID:25742751

  11. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Zhongxian Cheng; Yan Cao; John Smith

    2006-09-30

    This report is to present the progress made on the project entitled ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period July 1, 2006 through September 30, 2006. The following activities have been completed: the steel floor grating around the riser in all levels and the three-phase power supply for CFBC System was installed. Erection of downcomers, loop seals, ash bunker, thermal expansion joints, fuel and bed material bunkers with load cells, rotary air-lock valves and fuel flow monitors is underway. Pilot-scale slipstream tests conducted with bromine compound addition were performed for two typical types of coal. The purposes of the tests were to study the effect of bromine addition on mercury oxidization. From the test results, it was observed that there was a strong oxidization effect for Powder River Basin (PRB) coal. The proposed work for next quarter and project schedule are also described.

  12. Numerical Simulation of Physical and Chemical Processes in Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Baturin, D. A.; Gil, A. V.

    2015-10-01

    The paper presents a numerical simulation of the furnace with a circulating fluidized bed. Numerical study carried out for the bottom of the combustion chamber with the varying heights of volume filling. The results contours of particulate matter concentration and of velocities, as well as a graphical representation of changes in the concentration of particles on the bed height are shown. Simulation performed in Eulerian - Eulerian representation on a 2D model.

  13. Heat exchanger support apparatus in a fluidized bed

    SciTech Connect

    Lawton, C.W.

    1982-05-25

    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 there through to prevent deterioration of the support. 2 figs.

  14. Fluidized bed gasification ash reduction and removal process

    DOEpatents

    Schenone, Carl E. (Madison, PA); Rosinski, Joseph (Vanderbilt, PA)

    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.

  15. Fluidized bed gasification ash reduction and removal system

    DOEpatents

    Schenone, Carl E. (Madison, PA); Rosinski, Joseph (Vanderbilt, PA)

    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. 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.

  17. Fluidized-Bed Waste-Heat Recovery System Advances 

    E-print Network

    Patch, K. D.; Cole, W. E.

    1986-01-01

    industrial furnaces. where dirty and corrosive flue gases cause severe fouling and materials problems. The FBWHR system solves these problems by using a durable, direct contact heat exchanger, eliminating conventional gas-to-air heat exchanger surfaces.... In the FBWHR system, a recirculating partic ulate medium is heated as it falls through upward flowing flue gases in a raining-bed heat exchanger. This heated medium is passed across a fluidized bed heat exchanger, preheating the combustion air. Cooled...

  18. 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.

  19. Degradation of dimethyl sulfoxide through fluidized-bed Fenton process.

    PubMed

    Matira, Emmanuela M; Chen, Teng-Chien; Lu, Ming-Chun; Dalida, Maria Lourdes P

    2015-12-30

    Dimethyl sulfoxide (DMSO), one of the most widely used solvent, was subjected to fluidized-bed Fenton oxidation in this study. Fenton oxidation is considered one of the cheapest advanced oxidation processes due to high availability of Fenton's reagents Fe(2+) and H2O2, wherein, Fe(2+) catalyzes hydroxyl radical production from H2O2. Fluidized-bed Fenton process is a modified approach which is also used to address the production of large amount of iron oxide sludge in conventional Fenton process. Parametric study is included in this research using initial conditions of pH 2-7, 0.5-7.25mM Fe(2+), 5-87.5mM H2O2, and 5-50mM DMSO. Fluidized-bed Fenton oxidation of 5mM DMSO using 68.97g/L SiO2 carrier at initial conditions of pH 3, 5mM Fe(2+), and 32.5mM H2O2 resulted to 95.22% DMSO degradation, 34.38% TOC removal and 0.304mM sulfate/mM DMSO0 production in 2h. The study shows that the intermediate product which was most difficult to oxidize and contributed most to the residual TOC was methanesulfonate. PMID:26188864

  20. A NEW INTERPHASE FORCE IN TWO-PHASE FLUIDIZED BEDS

    SciTech Connect

    D. ZHANG; W. VANDERHEYDEN

    2001-05-01

    Mesoscale structures such as particle clusters have been observed both in experiments and in numerical simulations of circulating fluidized beds. In a numerical simulation, in order to account for the effects of such mesoscale structures, the computational grids have to be fine enough. The use of such fine grids is impractical in engineering applications due to excessive computational costs. To predict the macroscopic behavior of a fluidized bed with reasonable computation cost, they perform a second average over the averaged equations for two-phase flows. A mesoscale inter-phase exchange force is found to be the correlation of the particle volume fraction and the pressure gradient. This force is related to the mesoscale added mass of the two-phase flow. Typically, added mass for particle scale interactions is negligible in gas-solid flows since the gas density is small compared to density of solid particles. However, for a mesoscale structure, such as a bubble, the surrounding media is the mixture of gas and particles. The surrounding fluid density experienced by the mesoscale structure is the density of the surrounding mixture. Therefore, the added mass of a mesoscale structure, such as bubbles, cannot be neglected. The property of this new force is studied based on the numerical simulation of a fluidized bed using high grid resolution. It is shown that this force is important in the region where the particle volume fraction is high. The effects of the inhomogeneity to the interphase drag are also studied.

  1. Staged fluidized-bed combustion and filter system

    DOEpatents

    Mei, Joseph S. (Morgantown, WV); Halow, John S. (Waynesburg, PA)

    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.

  2. Investigation on Agropellet Combustion in the Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Isemin, R. L.; Konayahin, V. V.; Kuzmin, S. N.; Zorin, A. T.; Mikhalev, A. V.

    Agricultural wastes (straw, sunflower or millet husk, etc.) are difficult to use as fuel because of low bulk density and relatively big ash content with a low melting point. It is possible to produce agropellets of agricultural wastes which are suggested to combust in a fluidized bed of pellets alone, their char particles and ash. The characteristics of the process of fluidization of agropellets are investigated at room temperature. The experiments on agropellet combustion in a fluidized bed are carried out in an experimental set-up. The results of the experiments have shown that in such a bed the pellets produced of straw and millet husk combust with the same rate as those of wood though the latter contain 8.76 - 19.4 times less ash. The duration of combustion of the same portion of straw pellets in a fluidized bed is 3.74 - 7.01 times less than the duration of combustion of cut straw in a fixed bed. Besides, the movement of agropellets prevents agglomeration and slagging of a boiler furnace.

  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. Wood Gasification in a Lab-Scale Bubbling Fluidized Bed: Experiment and Simulation

    NASA Astrophysics Data System (ADS)

    He, L.; Schotte, E.; Thomas, S.; Schlinkert, A.; Herrmann, A.; Mosch, V.; Rajendran, V.; Heinrich, S.

    In theory, an integrated biomass gasification and fuel cell system has a higher overall plant efficiency when compared to the efficiency of biomass gasification combined with simple combustion systems and gas engines. In order to develop a prototype of this new concept of power plant operating in the range of l50kW to 5MW, several institutes of the Max Planck Society and the Fraunhofer-Gesellschaft in Germany have been working on the ProBio project with focus on the theoretical and experimental investigation of an integrated 1-2kWe system. The paper will firstly describe the gasification unit of the system: a lab-scale atmospheric bubbling fluidized bed gasifier. Wood gasification experiments were conducted and the influence of operation parameters, i.e. gasification agents, equivalence ratio ER and steam to biomass ratio SIB on gas yield and gas composition was analyzed. In parallel with the experimental work, chemical kinetics of wood gasification was studied and simulated. Furthermore, simulation of bubbling fluidized bed hydrodynamics at high temperature, using commercial computational fluid dynamics (CFD) software FLUENT, was also conducted to better understand the phenomenon of fluidization inside the bed.

  5. 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.

  6. State of Industrial Fluidized Bed Combustion 

    E-print Network

    Mesko, J. E.

    1982-01-01

    , they rray not have long to wait. Several FBC units are nON in operation. A wide range of boiler designs and capacities are be ing developed and finns such as COmbustion Engineer ing, Foster Wheeler, Jolmston Boiler and Riley Babcock, ani their backers... quantities of sulfur and vanadium has been derronstratOO. An industrial scale Fluid izOO Boo gasification system is presently in ser vice with the capibility of firing liquid petrol eum fuels, coal or lignite. Numerous FluidizOO Boo facilities...

  7. EXPERIMENTAL STUDY OF HIGH LEVELS OF SO2 REMOVAL IN ATMOSPHERIC-PRESSURE FUIDIZED-BED COMBUSTORS

    EPA Science Inventory

    The report describes tests conducted in an atmospheric-pressure-fluidized-bed combustor (FBC) with a cross-section of 1 x 1.6 m) to demonstrate high levels of S02 removal when burning a high-sulfur coal and feeding limestone sorbent for S02 removal. The goal was to achieve 90-plu...

  8. Lewis Pressurized, Fluidized-Bed Combustion Program. Data and Calculated Results

    NASA Technical Reports Server (NTRS)

    Rollbuhler, R. J.

    1982-01-01

    A 200 kilowatt (thermal), pressurized, fluidized bed (PFB) reactor and research test facility were designed, constructed, and operated. The facility was established to assess and evaluate the effect of PFB hot gas effluent on aircraft turbine engine materials that may have applications in stationary powerplant turbogenerators. The facility was intended for research and development work and was designed to operate over a wide range of conditions. These conditions included the type and rate of consumption of fuel (e.g., coal) and sulfur reacting sorbent material: the ratio of feed fuel to sorbent material; the ratio of feed fuel to combustion airflow; the depth of the fluidized reaction bed; the temperature and pressure in the reaction bed; and the type of test unit that was exposed to the combustion exhaust gases.

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

    DOEpatents

    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.

  10. 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.

  11. Occurrence of polycyclic aromatic hydrocarbons in dust emitted from circulating fluidized bed boilers.

    PubMed

    Kozielska, B; Konieczy?iski, J

    2008-11-01

    Occurrence of polycyclic aromatic hydrocarbons (PAHs) in granulometric fractions of dust emitted from a hard coal fired circulating fluidized bed (CFB) boiler was investigated. The dust was sampled with the use of a Mark III impactor. In each fraction of dust, by using gas chromatography (GC), 16 selected PAHs and total PAHs were determined and the toxic equivalent B(a)P (TE B(a)P) was computed. The results, recalculated for the standard granulometric fractions, are presented as concentrations and content of the determined PAHs in dust. Distributions of PAHs and their profiles in the granulometric dust fractions were studied also. The PAHs in dust emitted from the CFB boiler were compared with those emitted from mechanical grate boilers; a distinctly lower content of PAHs was found in dust emitted from the former. PMID:18975852

  12. Assessment of Drag Models for Geldart A Particles in Bubbling Fluidized Beds

    DOE PAGESBeta

    Estejab, Bahareh; Battaglia, Francine

    2015-10-08

    In order to accurately predict the hydrodynamic behavior of gas and solid phases using an Eulerian–Eulerian approach, it is crucial to use appropriate drag models to capture the correct physics. In this study, the performance of seven drag models for fluidization of Geldart A particles of coal, poplar wood, and their mixtures was assessed. In spite of the previous findings that bode badly for using predominately Geldart B drag models for fine particles, the results of our study revealed that if static regions of mass in the fluidized beds are considered, these drag models work well with Geldart A particles.more »It was found that drag models derived from empirical relationships adopt better with Geldart A particles compared to drag models that were numerically developed. Overall, the Huilin–Gidaspow drag model showed the best performance for both single solid phases and binary mixtures, however, for binary mixtures, Wen–Yu model predictions were also accurate.« less

  13. Assessment of Drag Models for Geldart A Particles in Bubbling Fluidized Beds

    SciTech Connect

    Estejab, Bahareh; Battaglia, Francine

    2015-10-08

    In order to accurately predict the hydrodynamic behavior of gas and solid phases using an Eulerian–Eulerian approach, it is crucial to use appropriate drag models to capture the correct physics. In this study, the performance of seven drag models for fluidization of Geldart A particles of coal, poplar wood, and their mixtures was assessed. In spite of the previous findings that bode badly for using predominately Geldart B drag models for fine particles, the results of our study revealed that if static regions of mass in the fluidized beds are considered, these drag models work well with Geldart A particles. It was found that drag models derived from empirical relationships adopt better with Geldart A particles compared to drag models that were numerically developed. Overall, the Huilin–Gidaspow drag model showed the best performance for both single solid phases and binary mixtures, however, for binary mixtures, Wen–Yu model predictions were also accurate.

  14. GREENHOUSE GAS EMISSIONS CONTROL BY OXYGEN FIRING IN CIRCULATING FLUIDIZED BED BOILERS

    SciTech Connect

    Nsakala ya Nsakala; Gregory N. Liljedahl

    2003-05-15

    Given that fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this study, ALSTOM Power Inc. (ALSTOM) has investigated several coal fired power plant configurations designed to capture CO{sub 2} from effluent gas streams for use or sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be more economical than in PC or Stoker firing, because recirculated gas flow can be reduced significantly. Oxygen-fired PC and Stoker units require large quantities of recirculated flue gas to maintain acceptable furnace temperatures. Oxygen-fired CFB units, on the other hand, can accomplish this by additional cooling of recirculated solids. The reduced recirculated gas flow with CFB units results in significant Boiler Island cost savings. Additionally, ALSTOM has identified several advanced/novel plant configurations, which improve the efficiency and cost of the CO{sub 2} product cleanup and compression process. These advanced/novel concepts require long development efforts. An economic analysis indicates that the proposed oxygen-firing technology in circulating fluidized boilers could be developed and deployed economically in the near future in enhanced oil recovery (EOR) applications or enhanced gas recovery (EGR), such as coal bed methane recovery. ALSTOM received a Cooperative Agreement from the US Department of Energy National Energy Technology Laboratory (DOE) in 2001 to carry out a project entitled ''Greenhouse Gas Emissions Control by Oxygen Firing in Circulating Fluidized Bed Boilers.'' This two-phased project is in effect from September 28, 2001, to October 27, 2004. (U.S. DOE NETL Cooperative Agreement No. DE-FC26-01NT41146). Phase I consisted of an evaluation of the technical feasibility and economics of alternate CO{sub 2} capture technologies applied to Greenfield US coal-fired electric generation power plants, and supporting bench-scale testing. And Phase II consists of pilot-scale testing, supporting a refined performance and economic evaluation of the oxygen-fired AFC concept. Phase I, detailed in this report, entails a comprehensive study evaluating the technical feasibility and economics of alternate CO{sub 2} capture technologies applied to Greenfield US coal-fired electric generation power plants. Thirteen separate but related cases (listed below), representing various levels of technology development, were evaluated as described herein. The first seven cases represent coal combustion cases in CFB type equipment. The next four cases represent Integrated Gasification Combined Cycle (IGCC) systems. The last two cases represent advanced Chemical Looping systems, which were completely paid for by ALSTOM and included herein for completeness.

  15. 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.

  16. Analysis of gas flow rate variation on fluidized bed combustor

    NASA Astrophysics Data System (ADS)

    Surjosatyo, Adi; Tama, Adhika Anindita

    2012-06-01

    The current study, related to the flow rate variation and the combustion feed, which were analyzed during combustion process in fluidized bed combustor at University of Indonesia. The air supplies used for this experiment were 0.085 and 0.095 m3/s. Both of air supply used with coconut shell as the biofuel, was applied to find correlation between the time and the fuel needed to achieve the self-sustaining combustion state. After the self-sustaining combustion achieved, the feed rate and its effect for the temperature are analyzed. It was found that the experiment with higher air supply gave higher output temperature in the freeboard area.

  17. Standby cooling system for a fluidized bed boiler

    DOEpatents

    Crispin, Larry G. (Akron, OH); Weitzel, Paul S. (Canal Fulton, OH)

    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.

  18. Combustion of Cattle Manure in a Fluidized Bed Combustor 

    E-print Network

    Annamalai, K.; Colaluca, M. A.; Ibrahim, M. Y.; Sweeten, J. M.

    1988-01-01

    stream_source_info ESL-IE-88-09-50.pdf.txt stream_content_type text/plain stream_size 16155 Content-Encoding ISO-8859-1 stream_name ESL-IE-88-09-50.pdf.txt Content-Type text/plain; charset=ISO-8859-1 COMBUSTION OF CATTLE... Station, Texas ABSTRACT 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...

  19. 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.

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

    SciTech Connect

    Robertson, A.; Bonk, D.L.

    1993-06-01

    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 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{degrees}C (2100{degrees}F) can be achieved. The carbonizer, PFB combustor, and particulate-capturing hot gas cleanup systems operate at 871{degrees}C (1600{degrees}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.

  1. Feasibility of recovering high valency metal cyanide complexes with a fluidized bed of resin

    SciTech Connect

    Nesbitt, A.B.; Petersen, F.W.

    1995-09-01

    A commercially available strong base ion-exchange resin IRA 958 was used to recover polyvalent metal cyanide complexes in a fluidized-bed application. A method for modeling the expansion of a fluidized bed of resin is proposed. The method takes into account the difficulties associated with the hydrodynamic characteristics of a macroporous resin of this nature.

  2. 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.

  3. 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. PMID:25263217

  4. Co-combustion of tannery sludge in a commercial circulating fluidized bed boiler.

    PubMed

    Dong, Hao; Jiang, Xuguang; Lv, Guojun; Chi, Yong; Yan, Jianhua

    2015-12-01

    Co-combusting hazardous wastes in existing fluidized bed combustors is an alternative to hazardous waste treatment facilities, in shortage in China. Tannery sludge is a kind of hazardous waste, considered fit for co-combusting with coal in fluidized bedboilers. In this work, co-combustion tests of tannery sludge and bituminous coal were conducted in a power plant in Jiaxing, Zhejiang province. Before that, the combustion behavior of tannery sludge and bituminous were studied by thermogravimetric analysis. Tannery sludge presented higher reactivity than bituminous coal. During the co-combustion tests, the emissions of harmful gases were monitored. The results showed that the pollutant emissions met the Chinese standard except for NOx. The Concentrations of seven trace elements (As, Cr, Cd, Ni, Cu, Pb, Mn) in three exit ash flows (bottom ash in bed, fly ash in filter, and submicrometer aerosol in flue gas) were analyzed. The results of mono-combustion of bituminous coal were compared with those of co-combustion with tannery sludge. It was found that chromium enriched in fly ash. At last, the leachability of fly ash and bottom ash was analyzed. The results showed that most species were almost equal to or below the limits except for As in bottom ashes and Cr in the fly ash of co-combustion test. The concentrations of Cr in leachates of co-combustion ashes are markedly higher than that of coal mono-combustion ashes. PMID:26278370

  5. An experimental investigation of sewage sludge gasification in a fluidized bed reactor.

    PubMed

    Calvo, L F; García, A I; Otero, M

    2013-01-01

    The gasification of sewage sludge was carried out in a simple atmospheric fluidized bed gasifier. Flow and fuel feed rate were adjusted for experimentally obtaining an air mass : fuel mass ratio (A/F) of 0.2 < A/F < 0.4. Fuel characterization, mass and power balances, produced gas composition, gas phase alkali and ammonia, tar concentration, agglomeration tendencies, and gas efficiencies were assessed. Although accumulation of material inside the reactor was a main problem, this was avoided by removing and adding bed media along gasification. This allowed improving the process heat transfer and, therefore, gasification efficiency. The heating value of the produced gas was 8.4 MJ/Nm, attaining a hot gas efficiency of 70% and a cold gas efficiency of 57%. PMID:24453863

  6. Operating costs and plant options analysis for the Shamokin fluidized bed boiler

    SciTech Connect

    Klett, M.G.; Dowdy, T.E.; Litman, R.

    1984-03-01

    This report presents the results of a study that examined the operating costs and options to improve the Shamokin Atmospheric Fluidized Bed Combustion Demonstration Plant located near Shamokin, Pennsylvania. The purpose of this study was to perform an operating cost analysis and compare the results with projected operating costs. An analysis was also made to identify possible cost savings options. Two base case scenarios were developed for this study: the first scenario assumed that the plant operated in a manner similar to operations during the extended test program; and the second scenario was concerned with two options. One option assumed upgrading the plant to achieve continuous full load operation, restarting, and used revised costs and revenues. The second assumed reconfiguring the plant for cogeneration.

  7. 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.

  8. An Experimental Investigation of Sewage Sludge Gasification in a Fluidized Bed Reactor

    PubMed Central

    Calvo, L. F.; García, A. I.; Otero, M.

    2013-01-01

    The gasification of sewage sludge was carried out in a simple atmospheric fluidized bed gasifier. Flow and fuel feed rate were adjusted for experimentally obtaining an air mass?:?fuel mass ratio (A/F) of 0.2 < A/F < 0.4. Fuel characterization, mass and power balances, produced gas composition, gas phase alkali and ammonia, tar concentration, agglomeration tendencies, and gas efficiencies were assessed. Although accumulation of material inside the reactor was a main problem, this was avoided by removing and adding bed media along gasification. This allowed improving the process heat transfer and, therefore, gasification efficiency. The heating value of the produced gas was 8.4?MJ/Nm, attaining a hot gas efficiency of 70% and a cold gas efficiency of 57%. PMID:24453863

  9. Multiscale probability distribution of pressure fluctuations in fluidized beds

    NASA Astrophysics Data System (ADS)

    Ghasemi, Fatemeh; Sahimi, Muhammad; Rahimi Tabar, M. Reza; Peinke, Joachim

    2012-07-01

    Analysis of flow in fluidized beds, a common chemical reactor, is of much current interest due to its fundamental as well as industrial importance. Experimental data for the successive increments of the pressure fluctuations time series in a fluidized bed are analyzed by computing a multiscale probability density function (PDF) of the increments. The results demonstrate the evolution of the shape of the PDF from the short to long time scales. The deformation of the PDF across time scales may be modeled by the log-normal cascade model. The results are also in contrast to the previously proposed PDFs for the pressure fluctuations that include a Gaussian distribution and a PDF with a power-law tail. To understand better the properties of the pressure fluctuations, we also construct the shuffled and surrogate time series for the data and analyze them with the same method. It turns out that long-range correlations play an important role in the structure of the time series that represent the pressure fluctuation.

  10. 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.

  11. 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.

  12. 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.

  13. Market Assessment and Technical Feasibility Study of Pressurized Fluidized Bed Combustion Ash Use

    SciTech Connect

    Bland, A.E.; Brown, T.H.

    1996-12-31

    Western Research Institute in conjunction with the Electric Power Research Institute, Foster Wheeler Energy International, Inc. and the U.S. Department of Energy Technology Center (METC), has undertaken a research and demonstration program designed to examine the market potential and the technical feasibility of ash use options for pressurized fluidized bed combustion (PFBC) ashes. The assessment is designed to address six applications, including: (1) structural fill, (2) road base construction, (3) supplementary cementing materials in portland cement, (4) synthetic aggregate, and (5) agricultural/soil amendment applications. Ash from low-sulfur subbituminous coal-fired Foster Wheeler Energia Oy pilot circulating PFBC tests in Karhula, Finland, and ash from the high-sulfur bituminous coal-fired American Electric Power (AEP) bubbling PFBC in Brilliant, Ohio, were evaluated in laboratory and pilot-scale ash use testing. This paper addresses the technical feasibility of ash use options for PFBC unit using low- sulfur coal and limestone sorbent (karhula ash) and high-sulfur coal and dolomite sorbents (AEP Tidd ash).

  14. Modeling of Carbochlorination of Zircon in Fluidized Bed Reactor

    NASA Astrophysics Data System (ADS)

    Jazini, M. H.; Ghoreishi, S. M.; Dadkhah, A. A.

    2010-02-01

    The chlorination of zircon is an integral part of the overall process for the production of zirconium. A two-phase hydrodynamic-type model was used to simulate the fluidized bed zircon carbochlorination reactor. In the plug-plug (P-P) model, the flow of gas in both dense and bubble phases was considered as a plug flow compared with the plug-mixed (P-M) model in which the flow in dense phase was assumed to be mixed. The zircon conversion obtained by model was compared with experimental measurements for model validation. The results of the P-M model indicated a stronger correlation with experimental data. Using the validated model, the effects of the zircon inlet size distribution, reactor temperature, inlet gas concentration, chlorine conversion velocity, and converted zircon were investigated. The results demonstrated that higher reactor temperature, smaller zircon size, and higher inlet gas velocity and concentration enhanced the chlorination rate.

  15. Numerical solution of a two-dimensional fluidized bed model

    NASA Astrophysics Data System (ADS)

    Christie, I.; Ganser, G. H.; Wilder, J. W.

    1998-09-01

    The numerical solution of a model describing a two-dimensional fluidized bed is considered. The model takes the form of a hyperbolic system of conservation laws with source term, coupled with an elliptic equation for determining a streamfunction. Operator splitting is used to produce homogeneous one-dimensional hyperbolic systems and ordinary differential equations involving the source term. The one-dimensional hyperbolic problems are solved using Roe's method with the addition of an entropy fix. The numerical procedure is second-order in time and first-order in space. Second-order-accuracy in space is obtained using flux limiting techniques. Numerical experiments which show the development of bubbles in the bed are presented. The familiar kidney-shaped bubble, observed experimentally, is found when using the method which is second-order in space. On the same mesh, the first-order method produces bubbles which are no longer kidney-shaped.

  16. 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.

  17. Successfully scale up catalytic gas-fluidized beds

    SciTech Connect

    Jazayeri, B.

    1995-04-01

    Catalytic gas-fluidized-bed (CGFB) processes offer several advantages over fixed-bed reactor systems including: temperature uniformity; continuous catalyst regeneration; large-scale single-train operation; ability to operate within the flammability envelope, thus allowing more compact equipment; and less complex reactor heat-exchange systems. CGFBs already have proven themselves in a variety of applications, such as acrylonitrile, fluid catalytic cracking (FCC), maleic anhydride, phthalic anhydride, vinyl chloride, and synthetic oil. So, in process development, it clearly makes sense to investigate the suitability of a CGFB process. Commercializing any new process can be a time-consuming effort, often requiring substantial capital expenditure and scale-up risk. Developing a CGFB process adds the complexity of fluidization and the challenge of catalyst development. In this article, the author provides a generalized procedure to address these issues in an optimal, cost-effective manner. This procedure has been used to successfully bring several CGFB processes to commercial reality.

  18. 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.

  19. Kinetics of fluidized bed combustion of wood pellets

    SciTech Connect

    Leckner, B.; Hansson, K.M.; Tullin, C.; Borodulya, A.V.; Dikalenko, V.I.; Palchonok, G.I.

    1999-07-01

    Devolatilization and char combustion of a single wood pellet in a fluidized bed has been studied. The effect of operation parameters (bed temperature, bed particle size, oxygen concentration) and pellet characteristics has been investigated. A simplified analytical model of heat-transfer controlled pyrolysis has been developed to interpret the measured volatiles release time. The model predictions are in a good agreement with the experimental data, provided that the initial physical properties of the pellet are used. The model can be used to estimate the devolatilization times in other combustion systems. Kinetic parameters of char combustion are obtained, based on the measured burnout times and simple model considerations. The physical properties of wood pellets need further study.

  20. 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.

  1. Computational Fluid Dynamics Simulation of Fluidized Bed Polymerization Reactors

    SciTech Connect

    Rong Fan

    2006-08-09

    Fluidized beds (FB) reactors are widely used in the polymerization industry due to their superior heat- and mass-transfer characteristics. Nevertheless, problems associated with local overheating of polymer particles and excessive agglomeration leading to FB reactors defluidization still persist and limit the range of operating temperatures that can be safely achieved in plant-scale reactors. Many people have been worked on the modeling of FB polymerization reactors, and quite a few models are available in the open literature, such as the well-mixed model developed by McAuley, Talbot, and Harris (1994), the constant bubble size model (Choi and Ray, 1985) and the heterogeneous three phase model (Fernandes and Lona, 2002). Most these research works focus on the kinetic aspects, but from industrial viewpoint, the behavior of FB reactors should be modeled by considering the particle and fluid dynamics in the reactor. Computational fluid dynamics (CFD) is a powerful tool for understanding the effect of fluid dynamics on chemical reactor performance. For single-phase flows, CFD models for turbulent reacting flows are now well understood and routinely applied to investigate complex flows with detailed chemistry. For multiphase flows, the state-of-the-art in CFD models is changing rapidly and it is now possible to predict reasonably well the flow characteristics of gas-solid FB reactors with mono-dispersed, non-cohesive solids. This thesis is organized into seven chapters. In Chapter 2, an overview of fluidized bed polymerization reactors is given, and a simplified two-site kinetic mechanism are discussed. Some basic theories used in our work are given in detail in Chapter 3. First, the governing equations and other constitutive equations for the multi-fluid model are summarized, and the kinetic theory for describing the solid stress tensor is discussed. The detailed derivation of DQMOM for the population balance equation is given as the second section. In this section, 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.

  2. Continuous fluidized-bed contactor with recycle of sorbent

    DOEpatents

    Scott, Charles D. (Oak Ridge, TN); Petersen, James N. (Moscow, ID); Davison, Brian H. (Knoxville, TN)

    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.

  3. 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.

  4. 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.

  5. 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.

  6. Mechanisms of coal-water mixture combustion in fluidized beds

    SciTech Connect

    Brown, R.C.

    1990-01-01

    The third quarter of work on fuel slurry combustion continued on in-situ determination of intrinsic reaction rates. Tracer gas tests with CO{sub 2} were performed to evaluate the validity of our simple models of reaction processes, which led to reinterpretation of some of our results from the previous quarter. We have compared our calcination rate data with previously published rates. We also offer an explanation why calcination in CWM agglomerates appears to be faster than sulfation. Finally, we return to the question of elutriation of unburned carbon and present results from tests with an on-line monitor for unburned carbon. 12 refs., 5 figs., 3 tabs.

  7. CO-PRODUCTION OF HYDROGEN AND ELECTRICITY USING PRESSURIZED CIRCULATING FLUIDIZED BED GASIFICATION TECHNOLOGY

    SciTech Connect

    Zhen Fan

    2006-05-30

    Foster Wheeler has completed work under a U.S. Department of Energy cooperative agreement to develop a gasification equipment module that can serve as a building block for a variety of advanced, coal-fueled plants. When linked with other equipment blocks also under development, studies have shown that Foster Wheeler's gasification module can enable an electric generating plant to operate with an efficiency exceeding 60 percent (coal higher heating value basis) while producing near zero emissions of traditional stack gas pollutants. The heart of the equipment module is a pressurized circulating fluidized bed (PCFB) that is used to gasify the coal; it can operate with either air or oxygen and produces a coal-derived syngas without the formation of corrosive slag or sticky ash that can reduce plant availabilities. Rather than fuel a gas turbine for combined cycle power generation, the syngas can alternatively be processed to produce clean fuels and or chemicals. As a result, the study described herein was conducted to determine the performance and economics of using the syngas to produce hydrogen for sale to a nearby refinery in a hydrogen-electricity co-production plant setting. The plant is fueled with Pittsburgh No. 8 coal, produces 99.95 percent pure hydrogen at a rate of 260 tons per day and generates 255 MWe of power for sale. Based on an electricity sell price of $45/MWhr, the hydrogen has a 10-year levelized production cost of $6.75 per million Btu; this price is competitive with hydrogen produced by steam methane reforming at a natural gas price of $4/MMBtu. Hence, coal-fueled, PCFB gasifier-based plants appear to be a viable means for either high efficiency power generation or co-production of hydrogen and electricity. This report describes the PCFB gasifier-based plant, presents its performance and economics, and compares it to other coal-based and natural gas based hydrogen production technologies.

  8. Low Temperature Chemical Vapor Deposition of Zirconium Nitride in a Fluidized Bed 

    E-print Network

    Arrieta, Marie

    2012-10-19

    The objective of this research was to design, assemble, and demonstrate the initial performance of a fluidized bed chemical vapor deposition (FB-CVD) system capable of producing thin, uniform zirconium nitride (ZrN) coatings (1 to 10 micrometers...

  9. Simulation and Life Cycle Assessment of Algae Gasification Process in Dual Fluidized Bed Gasifiers

    E-print Network

    Azadi, Pooya; Brownbridge, George; Mosbach, Sebastian; Inderwildi, Oliver; Kraft, Markus

    2015-01-01

    We present simulation results for the production of algae-derived syngas using dual fluidized bed (DFB) gasifiers. A global sensitivity analysis was performed to determine the impact of key input parameters (i.e. algae composition, gasification...

  10. PROCEDURES MANUAL FOR ENVIRONMENTAL ASSESSMENT OF FLUIDIZED-BED COMBUSTION PROCESSES

    EPA Science Inventory

    The document describes recommended procedures for sampling and analysis, for eventual use by source testing contractors, in support of the environmental assessment of fluidized-bed combustion (FBC) technology. The phased strategy involves two distinct levels of sampling and analy...

  11. Modeling of char oxidation in fluidized bed biomass gasifiers : effects of transport and chemical kinetics

    E-print Network

    Brooks, Amelia (Amelia Samek)

    2015-01-01

    Technologies for the conversion of biomass to liquid fuels are important to develop because the demand for liquid fuels remains unchanged even with the necessity of limiting dependence on fossil fuels. Fluidized Bed Biomass ...

  12. NUMERICAL AND EXPERIMENTAL ANALYSIS OF A FLUIDIZED BED FOR IFE TARGET LAYERING Kurt J. Boehm1

    E-print Network

    Raffray, A. René

    model and conducting laboratory-scale companion experiments to help understand the cryogenic fluidized and which includes a high-pressure deuterium filling station in addition to the cryogenic fluidized bed SCIENCE AND TECHNOLOGY VOL. 56 JULY 2

  13. TECHNOLOGY ASSESSMENT OF ANAEROBIC SYSTEMS FOR MUNICIPAL WASTEWATER TREATMENT: 1. ANAEROBIC FLUIDIZED BED. 2. ANFLOW

    EPA Science Inventory

    This report discusses two developing technologies for the treatment of municipal wastewaters. These technologies are anaerobic fluidized bed systems and an anaerobic fixed-film bioreactor (ANFLOW). The report discusses: available laboratory data on system performance; fluidized b...

  14. Experimental study of heat transfer to a horizontal tube in a large particle fluidized bed at elevated temperature

    SciTech Connect

    George, A.H.

    1982-01-01

    Experimental data for the time-average local heat transfer coefficient, to a single horizontal tube in a large particle fluidized bed at elevated temperature, are presented. An instrumented tube of 50.8 mm dia, employing the commercially available Micro-Foil Heat Flow Sensor with surface temperature thermocouple, was used. Heat tranfer measurements with excellent repeatability were made with the device. Refractory particles with surface mean diameter 2.14 mm and 3.23 mm were fluidized by combustion products of propane at bed temperatures of 810 K and 1053 K. The particle sizes are near the largest presently used in pilot plant fluidized bed coal combustors. The superficial gas velocity ranged from that required for minimum fluidization, or slightly packed, to the velocity where slugging first occurred, or the highest velocity air blower capacity would allow. Heat transfer results indicate that a stack of defluidized particles remain on top of the tube at low superficial gas velocities. A very low local heat transfer coefficient was obtained under these conditions. There was less than 10% difference in the maximum spatial-average heat transfer coefficients for the two particle sizes considered. The maximum spatial-average heat transfer coefficients were approximately 260 W/w/sup 2/ K and 370 W/m/sup 2/ K at bed temperatures of 810 K and 1053 K, respectively. Available heat transfer results, in the literature, were inadequate to either validate or invalidate the data presented.

  15. Hot-gas desulfurization. II. Use of gasifier ash in a fluidized-bed process. Final report

    SciTech Connect

    Schrodt, J.T.

    1981-02-01

    Three gasifier coal ashes were used as reactant/sorbents in batch fluidized-beds to remove hydrogen sulfide from hot, made-up fuel gases. It is predominantly the iron oxide in the ash that reacts with and removes the hydrogen sulfide; the sulfur reappears in ferrous sulfide. Sulfided ashes were regenerated by hot, fluidizing streams of oxygen in air; the sulfur is recovered as sulfur dioxide, exclusively. Ash sorption efficiency and sulfur capacity increase and stabilize after several cycles of use. These two parameters vary directly with the iron oxide content of the ash and process temperature, but are independent of particle size in the range 0.01 - 0.02 cm. A western Kentucky No. 9 ash containing 22 weight percent iron as iron oxide sorbed 4.3 weight percent sulfur at 1200/sup 0/F with an ash sorption efficiency of 0.83 at ten percent breakthrough. A global, fluidized-bed, reaction rate model was fitted to the data and it was concluded that chemical kinetics is the controlling mechanism with a predicted activation energy of 19,600 Btu/lb mol. Iron oxide reduction and the water-gas-shift reaction were two side reactions that occurred during desulfurization. The regeneration reaction occurred very rapidly in the fluid-bed regime, and it is suspected that mass transfer is the controlling phenomenon.

  16. Solids circulation around a jet in a fluidized bed gasifier. Final technical report, September 1, 1978-September 30, 1980

    SciTech Connect

    Gidaspow, D.; Ettehadieh, B.; Lin, C.; Goyal, A.; Lyczkowski, R.W.

    1980-01-01

    The object of this investigation was to develop an experimentally verified hydrodynamic model to predict solids circulation around a jet in a fluidized bed gasifier. Hydrodynamic models of fluidization use the principles of conservation of mass, momentum and energy. To account for unequal velocities of solid and fluid phases, separate phase momentum balances are developed. Other fluid bed models used in the scale-up of gasifiers do not employ the principles of conservation of momentum. Therefore, these models cannot predict fluid and particle motion. In such models solids mixing is described by means of empirical transfer coefficients. A two dimensional unsteady state computer code was developed to give gas and solid velocities, void fractions and pressure in a fluid bed with a jet. The growth, propagation and collapse of bubbles was calculated. Time-averaged void fractions were calculated that showed an agreement with void fractions measured with a gamma ray densitometer. Calculated gas and solid velocities in the jet appeared to be reasonable. Pressure and void oscillations also appear to be reasonable. A simple analytical formula for the rate of solids circulation was developed from the equations of change. It agrees with Westinghouse fluidization data in a bed with a draft tube. One dimensional hydrodynamic models were applied to modeling of entrained-flow coal gasification reactors and compared with data. Further development of the hydrodynamic models should make the scale-up and simulation of fluidized bed reactors a reality.

  17. Industrial Application Study on New-Type Mixed-Flow Fluidized Bed Bottom Ash Cooler

    NASA Astrophysics Data System (ADS)

    Zeng, B.; Lu, X. F.; Liu, H. Z.

    As a key auxiliary device of CFB boiler, the bottom ash cooler (BAC) has a direct influence on secure and economic operation of the boiler. The operating situation of domestic CFB power plant is complex and changeable with a bad coal-fired condition. The principle for designing BAC suitable for the bad coal-fired condition and high parameter CFB boilers was summarized in this paper. Meanwhile, a new-type mixed-flow fluidized bed bottom ash cooler was successfully designed on the basis of the comprehensive investigation on the existing BAC s merits and drawbacks. Using coarse/fine slag separation technology and micro-bubbling fluidization are the significant characteristics of this new BAC. This paper also puts great emphasis on its industrial test in a 460t/h CFB boiler. The results indicate that it achieves significant separation of the coarse/fine slag, an obvious cooling effect, no slag block and coking phenomenon, and continuous stable operation. Figs 7, Tabs 4 and Refs 11.

  18. Fine and ultrafine particles generated during fluidized bed combustion of different solid fuels

    SciTech Connect

    Urciuolo, M.; Barone, A.; D'Alessio, A.; Chirone, R.

    2008-12-15

    The paper reports an experimental study carried out with a 110-mm ID fluidized bed combustor focused on the characterization of particulates formation/emission during combustion of coal and non-fossil solid fuels. Fuels included: a bituminous coal, a commercial predried and granulated sludge (GS), a refuse-derived fuel (RDF), and a biomass waste (pine seed shells). Stationary combustion experiments were carried out analyzing the fate of fuel ashes. Fly ashes collected at the combustor exhaust were characterized both in terms of particle size distribution and chemical composition, with respect to both trace and major elements. Tapping-Mode Atomic Force Microscopy (TM-AFM) technique and high-efficiency cyclone-type collector devices were used to characterize the size and morphology of the nanometric-and micronic-size fractions of fly ash emitted at the exhaust respectively. Results showed that during the combustion process: I) the size of the nanometric fraction ranges between 2 and 65 nm; ii) depending on the fuel tested, combustion-assisted attrition or the production of the primary ash particles originally present in the fuel particles, are responsible of fine particle generation. The amount in the fly ash of inorganic compounds is larger for the waste-derived fuels, reflecting the large inherent content of these compounds in the parent fuels.

  19. Engineering systems analysis of pressurized fluidized-bed-combustion power systems

    SciTech Connect

    Graves, R.L.; Griffin, F.P.; Lackey, M.E.

    1982-04-01

    This effort was conducted to provde supporting data for the research and development program on pressurized fluidized bed combustor (PFBC) systems being continued under the auspices of the Office of Coal Utilization of DOE. This report deals with the first phase of the effort, designated Task 1, which was scoped to be a somewhat broad review of PFBC technology and an analysis to determine its potential and sensitivity to key development needs. Background information pertaining to the application of PFBC to the market for coal-fired technology is included. The status of development is reviewed and the deficiencies in data are identified. Responses to a survey of PFBC developers are reviewed with emphasis on the high risk areas of the PFBC concept. Some of these problems are: uncertainty of life of gas turbine components; lack of demonstration of load following; and hot solids handling. Some high risk areas, such as the gas cleanup or gas turbine systems, can be relieved by reducing the severity of design conditions such as the turbine inlet temperature. Alternate turbine designs or plant configurations are also possible solutions. Analyses were performed to determine whether the advantages held by PFBC systems in cost, efficiency, and emissions would be nullified by measures taken to reduce risk. In general, the results showed that the attractive features of the PFBC could be preserved.

  20. Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion System

    SciTech Connect

    Wei-Ping Pan; Yan Cao; John Smith

    2006-07-01

    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 April 1, 2006 through June 30, 2006. Substantial progress was made on the development and application of software for the effective operation and safe control of the Circulating Fluidized-Bed (CFB) Combustor, as well as for the display and logging of acquired data and operating parameters.

  1. Volatiles combustion in fluidized beds. Final technical report, 4 September 1992--4 June 1995

    SciTech Connect

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

    1996-02-29

    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 are being conducted to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. A review of the work conducted under this grant is presented in this Final Technical Report. Both experimental and theoretical work have been conducted to examine the inhibition of the combustion by the fluidized bed material, sand. It has been shown that particulate phase at incipient fluidization inhibits the combustion of propane by free radical destruction at the surface of sand particles within the particulate phase. The implications of these findings is that at bed temperatures lower than the critical temperatures, gas combustion can only occur in the bubble phase or at the top surface of a bubbling fluidized bed. In modeling fluidized bed combustion this inhibition by the particulate phase should be included.

  2. Overall and average local heat transfer from a horizontal cylinder in a gas-fluidized bed with an opposing oscillatory flow

    SciTech Connect

    Pence, D.V.; Beasley, D.E.

    1996-12-31

    The Pulsed Atmospheric Fluidized Bed Combustor (PAFBC), a hybrid combustor concept that couples a pulsed combustor with an atmospheric bubbling fluidized bed, has technical advantages in energy efficiency and emissions. The present study examines fundamental aspects of heat transfer in this hybrid combustor by measuring the effect of an opposing oscillatory flow on the overall and time-averaged local heat transfer in a laboratory scale bubbling gas-fluidized bed. This opposing secondary flow consisted of a steady mean component and an oscillating component thereby modeling the flow in the tailpipe of a pulsed combustor. Data were acquired for a monodisperse distribution of particles with a mean diameter of 345 {micro}m and total fluidization ratios ranging from 1.1 through 2.7. Overall and time-averaged local heat flux measurements from the surface of a submerged horizontal cylinder show that heat transfer characteristics are significantly altered by an opposing oscillatory flow. Increases in overall heat transfer on the order of 12% were identified for operating conditions with low primary and secondary flow rates and low pulse frequencies. These enhancements were identified to be a consequence of significant localized enhancements. The fundamental trends and magnitude of the particle Nusselt number are effectively characterized by a modified form of the Strouhal number.

  3. Separation of harmful impurities from refuse derived fuels (RDF) by a fluidized bed.

    PubMed

    Krüger, B; Mrotzek, A; Wirtz, S

    2014-02-01

    In firing systems of cement production plants and coal-fired power plants, regular fossil fuels are increasingly substituted by alternative fuels. Rising energy prices and ambitious CO2-reduction goals promote the use of alternative fuels as a significant contribution to efficient energy recovery. One possibility to protect energy resources are refuse-derived fuels (RDF), which are produced during the treatment of municipal solid, commercial and industrial waste. The waste fractions suitable for RDF have a high calorific value and are often not suitable for material recycling. With current treatment processes, RDF still contains components which impede the utilization in firing systems or limit the degree of substitution. The content of these undesired components may amount to 4 wt%. These, in most cases incombustible particles which consist of mineral, ceramic and metallic materials can cause damages in the conveying systems (e. g. rotary feeder) or result in contaminations of the products (e. g. cement, chalk). Up-to-date separation processes (sieve machine, magnet separator or air classifier) have individual weaknesses that could hamper a secure separation of these particles. This article describes a new technology for the separation of impurities from refuse derived fuels based on a rotating fluidized bed. In this concept a rotating motion of the particle bed is obtained by the tangential injection of the fluidization gas in a static geometry. The RDF-particles experience a centrifugal force which fluidized the bed radially. The technical principle allows tearing up of particle clusters to single particles. Radially inwards the vertical velocity is much lower thus particles of every description can fall down there. For the subsequent separation of the particles by form and density an additionally cone shaped plate was installed in the centre. Impurities have a higher density and a compact form compared to combustible particles and can be separated with a high efficiency. The new technology was experimentally investigated and proven using model-RDF, actual-RDF and impurities of different densities. In addition, numerical simulations were also done. The fluidization chamber was operated in batch mode. The article describes experiences and difficulties in using rotating fluidized bed systems. PMID:24252370

  4. Theoretical Investigation of the Process of Steam-Oxygen Gasification of Coke-Ash Particles in a Fluidized Bed Under Pressure

    NASA Astrophysics Data System (ADS)

    Rokhman, B. B.

    2015-03-01

    The problem on the evolution of the state of an ensemble of reacting coke-ash particles in a fluidized-bed gas generator is considered. A kinetic equation for the distribution function of particles within small ranges of carbon concentration variation for the stages of surface and bulk reaction has been constructed and integrated. Boundary conditions ("matching" conditions) at the boundaries between these ranges are formulated. The influence of the granulometric composition of the starting coal, height, porosity, and of the bed temperature on the process of steam-oxygen gasification of coke-ash particles of individual sorts of fuel and of a binary coal mixture has been investigated.

  5. Comparison of the effect of grounding the column wall in gas-solid fluidized beds on electrostatic charge generation

    NASA Astrophysics Data System (ADS)

    Sowinski, Andrew; Mayne, Antonio; Javed, Bassam; Mehrani, Poupak

    2011-06-01

    In gas-solid fluidized beds as particles are fluidized, they continuously come into contact with other particles, as well as the fluidization column wall. This generates electrostatic charges by means of triboelectrification and frictional charging, leading to particle agglomeration, reactor wall fouling, and eventually process downtime and large financial losses. Grounding the fluidization column has been considered as a means of helping electrostatic charge dissipation within fluidized beds; however, in industrial applications despite the process vessels being grounded, the electrostatic problem still persists. This work focused on the effect of fluidization column grounding on particle wall fouling. Experiments were conducted in an atmospheric system consist of a 0.1 m in diameter carbon steel fluidization column. The mass and charge-to-mass ratio (q/m) of the particles that remained adhered to the column wall upon the completion of one hour fluidization period were measured in an electrically isolated and grounded columns to quantitatively determine the amount of reactor wall fouling. Polyethylene particles with different particle size ranges (300- 1000 ?m) were fluidized with extra dry air at 1.5 times their respective minimum fluidization velocity (umf). Results obtained in the grounded fluidization column were not significantly different from those in the isolated column for all particle size ranges tested where the particles mass collected and q/m and were found to be generally similar.

  6. 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.

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

    DOEpatents

    Isaksson, Juhani (Karhula, FI); Koskinen, Jari (Karhula, FI)

    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).

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

    DOEpatents

    Fasching, George E. (Morgantown, WV); Utt, Carroll E. (Morgantown, WV)

    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).

  9. Electrical and electrochemical behavior of fluidized bed electrodes

    SciTech Connect

    Huh, T.; Evans, J.W.

    1987-02-01

    A probe has been used to simultaneously measure the electrolyte and particle potentials within a fluidized bed electrode. The difference between the two signals then yielded the overpotential. Transients of all three potentials were stored by a microcomputer and the data processed to yield potential probability distributions and power spectra. Experiments were performed on beds of copper particles undergoing cathodic deposition from acidified sulfate solution and on beds of zinc-coated particles undergoing deposition or dissolution of zinc with an alkaline zincate electrolyte. Both low frequency and wide band noise were observed in the potentials of copper particles while the former was much less for zinc-coated polymer particles. An explanation was offered in terms of the hydrodynamics of the electrode, particularly the presence or absence of rising particle-free regions (''bubbles''). The distributions of time-averaged potentials with position in the bed were measured and found to be in qualitative agreement with theory. Preliminary results on a moving bed electrode are reported.

  10. Estuarine nitrification: A naturally occurring fluidized bed reaction?

    NASA Astrophysics Data System (ADS)

    Owens, N. J. P.

    1986-01-01

    The rates of nitrification in the water column of the Tamar river estuary, southwest England have been measured using the incorporation of H 14CO 3 in samples with and without the inhibitor of nitrification, 2-chloro-6-(trichloromethyl) pyridine ( N-Serve). N-Serve proved successful in totally inhibiting NH 4-oxidizing bacteria but the activity of NO 2-oxidizing bacteria was inhibited by only 30%; other organisms were only slightly affected. Measurements of the nitrification rate made over the entire salinity range of the estuary (0-30‰) showed that maximum nitrification always coincided with the turbidity maximum. The field data suggest that the organisms responsible for nitrification were associated with periodically resuspended particulate material and that the turbidity maximum acts in a manner similar to a fluidized bed reactor. A dispersion model has been used to demonstrate that nitrification in the water column can account for 100% of the NO 2 maximum which is apparent down estuary from the turbidity maximum.

  11. 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.

  12. 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

  13. Modeling of devolatilization in circulating fluidized bed combustion

    SciTech Connect

    Stenseng, M.; Lin, W.; Johnsson, J.E.; Dam-Johansen, K.

    1997-12-31

    A mathematical model is developed to describe the devolatilization process in a circulating fluidized bed combustor. The model is a combination of two submodels: single particle devolatilization and fluid dynamics. The single particle model includes the influence of both chemical kinetics and heat transfer on the rate of devolatilization. The results show a good agreement with literature data. The fluid dynamic model describes the main characteristics of a CFB: a dense zone in the bottom, followed by a splash zone and a dilute zone with a core-annulus structure. Each zone is modeled as a number of CSTR`s and the size and number of CSTR`s has been estimated from tracer experiments in an 80 MW{sub th} CFB boiler. It was not possible to evaluate the model against experimental data, but the dependence of particle size on the degree of devolatilization in the dense bed agrees qualitative with the expected behavior. The mode4l shows that the devolatilization mainly occurs in the dense bed.

  14. Heavy metal characterization of circulating fluidized bed derived biomass ash.

    PubMed

    Li, Lianming; Yu, Chunjiang; Bai, Jisong; Wang, Qinhui; Luo, Zhongyang

    2012-09-30

    Although the direct combustion of biomass for energy that applies circulating fluidized bed (CFB) technology is steadily expanding worldwide, only few studies have conducted an environmental assessment of biomass ash thus far. Therefore, this study aims to integrate information on the environmental effects of biomass ash. We investigated the concentration of heavy metal in biomass ash samples (bottom ash, cyclone ash, and filter ash) derived from a CFB boiler that combusted agricultural and forest residues at a biomass power plant (2×12 MW) in China. Ash samples were gathered for the digestion and leaching test. The heavy metal content in the solution and the leachate was studied via an inductively coupled plasma-mass spectrometer and a Malvern Mastersizer 2000 mercury analyzer. Measurements for the chemical composition, particle size distribution, and the surface morphology were carried out. Most of the metals in cyclone ash particles were enriched, whereas Ti and Hg were enriched in filter ash. Residence time contributed most to heavy metal enrichment. Under HJ/T 300 conditions, the heavy metals showed serious leaching characteristics. Under EN 12457-2 conditions, leaching behavior was hardly detected. PMID:22840499

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Cyclone performance; The key to feed utilization in circulating fluidized bed boilers

    SciTech Connect

    Tsao, T.R.; Herb, B.E.; Lewnard, J.J.; Wang, S.I. )

    1992-01-01

    High utilization of coal and limestone feedstock in circulating fluidized bed (CFB) combustors is critical to minimize operating costs and solid waste generation. Pilot-scale test results typically indicate 50% calcium utilization (Ca/S = 1:1) and greater than 99% carbon burnout. Recent performance data taken for Stockton CFB indicates that a large fraction of the unburned carbon and unreacted limestone escapes the boiler with the fly ash particles smaller than 100 {mu}m in size. This observation was explained by the short residence times of fine particles in the CFB boiler. An analysis of the CFB system suggests that this problem is caused by the inability of the cyclone to capture smaller particles and return them to the boiler to be more completely utilized. This paper reports that a sensitivity study revealed that feedstock utilization is sensitive to cyclone grade efficiency for small particle sizes. in addition, the results show how bed particle size, fly-bottom ash split, solids recirculation rate, and heat transfer in CFB's are affected by cyclone performance.

  4. Desulfurization of fuel gases in fluidized bed gasification and hot fuel gas cleanup systems

    DOEpatents

    Steinberg, M.; Farber, G.; Pruzansky, J.; Yoo, H.J.; McGauley, P.

    1983-08-26

    A problem with the commercialization of fluidized bed gasification is that vast amounts of spent sorbent are generated if the sorbent is used on a once-through basis, especially if high sulfur coals are burned. The requirements of a sorbent for regenerative service in the FBG process are: (1) it must be capable of reducing the sulfur containing gas concentration of the FBG flue gas to within acceptable environmental standards; (2) it must not lose its reactivity on cyclic sulfidation and regeneration; (3) it must be capable of regeneration with elimination of substantially all of its sulfur content; (4) it must have good attrition resistance; and, (5) its cost must not be prohibitive. It has now been discovered that calcium silicate pellets, e.g., Portland cement type III pellets meet the criteria aforesaid. Calcium silicate removes COS and H/sub 2/S according to the reactions given to produce calcium sulfide silicate. The sulfur containing product can be regenerated using CO/sub 2/ as the regenerant. The sulfur dioxide can be conveniently reduced to sulfur with hydrogen or carbon for market or storage. The basic reactions in the process of this invention are the reactions with calcium silicate given in the patent. A convenient and inexpensive source of calcium silicate is Portland cement. Portland cement is a readily available, widely used construction meterial.

  5. A Study of Vertical Gas Jets in a Bubbling Fluidized Bed

    SciTech Connect

    Steven Ceccio; Jennifer Curtis

    2011-01-18

    A detailed experimental study of a vertical gas jet impinging a fluidized bed of particles has been conducted with the help of Laser Doppler Velocimetry measurements. Mean and fluctuating velocity profiles of the two phases have been presented and analyzed for different fluidization states of the emulsion. The results of this work would be greatly helpful in understanding the complex two-phase mixing phenomenon that occurs in bubbling beds, such as in coal and biomass gasification, and also in building more fundamental gas-solid Eulerian/Lagrangian models which can be incorporated into existing CFD codes. Relevant simulations to supplement the experimental findings have also been conducted using the Department of Energyâ??s open source code MFIX. The goal of these simulations was two-fold. One was to check the two-dimensional nature of the experimental results. The other was an attempt to improve the existing dense phase Eulerian framework through validation with the experimental results. In particular the sensitivity of existing frictional models in predicting the flow was investigated. The simulation results provide insight on wall-bounded turbulent jets and the effect frictional models have on gas-solid bubbling flows. Additionally, some empirical minimum fluidization correlations were validated for non-spherical particles with the idea of extending the present study to non-spherical particles which are more common in industries.

  6. Desulfurizing Coal With an Alkali Treatment

    NASA Technical Reports Server (NTRS)

    Ravindram, M.; Kalvinskas, J. J.

    1987-01-01

    Experimental coal-desulfurization process uses alkalies and steam in fluidized-bed reactor. With highly volatile, high-sulfur bituminous coal, process removed 98 percent of pyritic sulfur and 47 percent of organic sulfur. Used in coal liquefaction and in production of clean solid fuels and synthetic liquid fuels. Nitrogen or steam flows through bed of coal in reactor. Alkalies react with sulfur, removing it from coal. Nitrogen flow fluidizes bed while heating or cooling; steam is fluidizing medium during reaction.

  7. 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.

  8. CRUCIBLE TESTING OF TANK 48H RADIOACTIVEWASTE SAMPLE USING FLUIDIZED BED STEAMREFORMING TECHNOLOGY FOR ORGANICDESTRUCTION

    SciTech Connect

    Crawford, C

    2008-07-31

    The purpose of crucible scale testing with actual radioactive Tank 48H material was to duplicate the test results that had been previously performed on simulant Tank 48H material. The earlier crucible scale testing using simulants was successful in demonstrating that bench scale crucible tests produce results that are indicative of actual Fluidized Bed Steam Reforming (FBSR) pilot scale tests. Thus, comparison of the results using radioactive Tank 48H feed to those reported earlier with simulants would then provide proof that the radioactive tank waste behaves in a similar manner to the simulant. Demonstration of similar behavior for the actual radioactive Tank 48H slurry to the simulant is important as a preliminary or preparation step for the more complex bench-scale steam reformer unit that is planned for radioactive application in the Savannah River National Laboratory (SRNL) Shielded Cells Facility (SCF) later in 2008. The goals of this crucible-scale testing were to show 99% destruction of tetraphenylborate and to demonstrate that the final solid product produced is sodium carbonate. Testing protocol was repeated using the specifications of earlier simulant crucible scale testing, that is sealed high purity alumina crucibles containing a pre-carbonated and evaporated Tank 48H material. Sealing of the crucibles was accomplished by using an inorganic 'nepheline' sealant. The sealed crucibles were heat-treated at 650 C under constant argon flow to inert the system. Final product REDOX measurements were performed to establish the REDuction/OXidation (REDOX) state of known amounts of added iron species in the final product. These REDOX measurements confirm the processing conditions (pyrolysis occurring at low oxygen fugacity) of the sealed crucible environment which is the environment actually achieved in the fluidized bed steam reformer process. Solid product dissolution in water was used to measure soluble cations and anions, and to investigate insoluble fractions of the product solids. Radioanalytical measurements were performed on the Tank 48H feed material and on the dissolved products in order to estimate retention of Cs-137 in the process. All aspects of prior crucible scale testing with simulant Tank 48H slurry were demonstrated to be repeatable with the actual radioactive feed. Tetraphenylborate destruction was shown to be >99% and the final solid product is sodium carbonate crystalline material. Less than 10 wt% of the final solid products are insoluble components comprised of Fe/Ni/Cr/Mn containing sludge components and Ti from monosodium titanate present in Tank 48H. REDOX measurements on the radioactive solid products indicate a reducing atmosphere with extremely low oxygen fugacity--evidence that the sealed crucible tests performed in the presence of a reductant (sugar) under constant argon purge were successful in duplicating the pyrolysis reactions occurring with the Tank 48H feed. Soluble anion measurements confirm that using sugar as reductant at 1X stoichiometry was successful in destroying nitrate/nitrite in the Tank 48H feed. Radioanalytical measurements indicate that {approx}75% of the starting Cs-137 is retained in the solid product. No attempts were made to analyze/measure other potential Cs-137 in the process, i.e., as possible volatile components on the inner surface of the alumina crucible/lid or as offgas escaping the sealed crucible. The collective results from these crucible scale tests on radioactive material are in good agreement with simulant testing. Crucible scale processing has been shown to duplicate the complex reactions of an actual fluidized bed steam reformer. Thus this current testing should provide a high degree of confidence that upcoming bench-scale steam reforming with radioactive Tank 48H slurry will be successful in tetraphenylborate destruction and production of sodium carbonate product.

  9. Experimental study on combustion characteristics and NOX emissions of pulverized anthracite preheated by circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Zhu, Jian-Guo; Lu, Qing-Gang

    2011-08-01

    A 30 kW bench-scale rig of pulverized anthracite combustion preheated by a circulating fluidized bed (CFB) was developed. The CFB riser has a diameter of 90 mm and a height of 1,500 mm. The down-fired combustion chamber (DFCC) has a diameter of 260 mm and a height of 3,000 mm. Combustion experiments were carried out using pulverized anthracite with 6.74% volatile content. This low volatile coal is difficult to ignite and burn out. Therefore, it requires longer burnout time and higher combustion temperature, which results in larger NOX emissions. In the current study, important factors that influence the combustion characteristics and NOX emissions were investigated such as excess air ratio, air ratio in the reducing zone, and fuel residence time in the reducing zone. Pulverized anthracite can be quickly preheated up to 800°C in CFB when the primary air is 24% of theoretical air for combustion, and the temperature profile is uniform in DFCC. The combustion efficiency is 94.2%, which is competitive with other anthracite combustion technologies. When the excess air ratio ranges from 1.26 to 1.67, the coal-N conversion ratio is less than 32% and the NOX emission concentration is less than 371 mg/m3 (@6% O2). When the air ratio in the reducing zone is 0.12, the NOX concentration is 221 mg/m3 (@6% O2), and the coal-N conversion ratio is 21%, which is much lower than that of other boilers.

  10. ADVANCED SORBENT DEVELOPMENT PROGRAM; DEVELOPMENT OF SORBENTS FOR MOVING-BED AND FLUIDIZED-BED APPLICATIONS

    SciTech Connect

    AYALA, R E; VENKATARAMANI, V S

    1998-09-30

    The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 °C (900-1000 °F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.'s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 °C (650 °F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes. The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 °C (650-1000 °F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a cost assessment and a market plan for large-scale fabrication of sorbents were developed. As an optional task, long-term bench-scale tests of the best moving-bed sorbents were conducted. Starting from thermodynamic calculations, several metal oxides were identified for potential use as hot gas cleanup sorbents using constructed phase stability diagrams and laboratory screening of various mixed-metal oxide formulations. Modified zinc titanates and other proprietary metal oxide formulations were evaluated at the bench scale and many of them found to be acceptable for operation in the target desulfurization temperature range of 370 °C (700 °F) to 538 °C (1000 °F) and regeneration tempera-tures up to 760 °C (1400 °F). Further work is still needed to reduce the batch-to-batch repeatability in the fabrication of modified zinc titanates for larger scale applications. The information presented in this Volume 1 report contains the results of moving-bed sorbent develop-ment at General Electric's Corporate Research and Development (GE-CRD). A separate Volume 2 report contains the results of the subcontract on fluidized-bed sorbent development at the Institute of Gas Technology (IGT).

  11. ADVANCED SORBENT DEVELOPMENT PROGRAM DEVELOPMENT OF SORBENTS FOR MOVING-BED AND FLUIDIZED-BED APPLICATIONS

    SciTech Connect

    R.E Ayala; V.S. Venkataramani; Javad Abbasian; Rachid B. Slimane; Brett E. Williams; Minoo K. Zarnegar; James R. Wangerow; Andy H. Hill

    2000-03-31

    The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 C (900-1000 F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.'s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 C (650 F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes. The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 C (650-1000 F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a cost assessment and a market plan for large-scale fabrication of sorbents were developed. As an optional task, long-term bench-scale tests of the best moving-bed sorbents were conducted. Starting from thermodynamic calculations, several metal oxides were identified for potential use as hot gas cleanup sorbents using constructed phase stability diagrams and laboratory screening of various mixed-metal oxide formulations. Modified zinc titanates and other proprietary metal oxide formulations were evaluated at the bench scale and many of them found to be acceptable for operation in the target desulfurization temperature range of 370 C (700 F) to 538 C (1000 F) and regeneration temperatures up to 760 C (1400 F). Further work is still needed to reduce the batch-to-batch repeatability in the fabrication of modified zinc titanates for larger scale applications. The information presented in this Volume 1 report contains the results of moving-bed sorbent development at General Electric's Corporate Research and Development (GE-CRD). A separate Volume 2 report contains the results of the subcontract on fluidized-bed sorbent development at the Institute of Gas Technology (IGT).

  12. Task 3.8 - pressurized fluidized-bed combustion

    SciTech Connect

    1995-03-01

    The focus of this work on pressurized fluidized-bed combustion (PFBC) is the development of sorbents for in-bed alkali control. The goal is to generate fundamental process information for development of a second-generation PFBC. Immediate objectives focus on the performance of sulfur sorbents, fate of alkali, and the Resource Conservation and Recovery Act (RCRA) heavy metals. The studies reported here focus on emission control strategies applied in the bed. Data from shakedown testing, alkali sampling, sulfur sorbent performance tests, and refuse-derived fuel (RDF) and lignite combustion tests are presented in detail. Initial results from the characterization of alkali gettering indicate that in-bed getters can remove a significant amount of alkali from the bed. Using kaolin as a sorbent, sodium levels in the flue gas were reduced from 3.6 ppm to less than 0.22 ppm. Sulfur was also reduced by 60% using the kaolin sorbent. Preliminary sulfur sorbent testing, which was designed to develop a reliable technique to predice sorbent performance, indicate that although the total sulfur capture is significantly lower than that observed in a full-scale PFBC, the emission trends are similar. RDF and RDF-lignite fuels had combustion efficiencies exceeding 99.0% in all test cases. Sulfur dioxide emission was significantly lower for the RDF fuels than for lignite fuel alone. Nitrogen oxide emission was also lower for the RDF-based fuels than for the lignite fuel. Both emission gases were well below current regulatory limits. Carbon monoxide and hydrocarbon emissions appeared to be slightly higher for the fuels containing RDF, but were below 9 ppm for the worst case. Analysis of volatile organic compound emission does not indicate an emission problem for these fuels. Chromium appears to be the only RCRA metal that might present some disposal problem; however, processing of the RDF with the wet resource recovery method should reduce chromium levels. 2 refs., 13 figs., 15 tabs.

  13. 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.

  14. 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/.

  15. 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.

  16. 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.

  17. 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.

  18. Cofiring lignite with hazelnut shell and cotton residue in a pilot-scale fluidized bed combustor

    SciTech Connect

    Zuhal Gogebakan; Nevin Selcuk

    2008-05-15

    In this study, cofiring of high ash and sulfur content lignite with hazelnut shell and cotton residue was investigated in 0.3 MWt METU Atmospheric Bubbling Fluidized Bed Combustion (ABFBC) Test Rig in terms of combustion and emission performance of different fuel blends. The results reveal that cofiring of hazelnut shell and cotton residue with lignite increases the combustion efficiency and freeboard temperatures compared to those of lignite firing with limestone addition only. CO{sub 2} emission is not found sensitive to increase in hazelnut shell and cotton residue share in fuel blend. Cofiring lowers SO{sub 2} emissions considerably. Cofiring of hazelnut shell reduces NO and N{sub 2}O emissions; on the contrary, cofiring cotton residue results in higher NO and N{sub 2}O emissions. Higher share of biomass in the fuel blend results in coarser cyclone ash particles. Hazelnut shell and cotton residue can be cofired with high ash and sulfur-containing lignite without operational problems. 32 refs., 12 figs., 11 tabs.

  19. Experimental investigation of gas-particle flows through diffusers in the freeboard region of fluidized beds

    SciTech Connect

    Kale, S.R.

    1984-01-01

    An experimental study on the effects of straight walled diffusers on elutriation and flow properties in the freeboard region of fluidized beds was conducted as a possible means of reducing elutriation. A bed 150 mm x 150 mm in cross section, 915 mm high followed by 615 mm long diffuser and 305 mm long straight section was constructed. Glass beads (50-100 ..mu..m diameter) were fluidized by air at atmospheric pressure in the bubbling regime. Elutriation rate measurements with an isokinetic sampler indicated: 1) an exponential increase in elutriation rate with increasing air velocity, independent of bed height and diffuser configuration; and 2) a monotonic decrease in elutriation rate for diffusers located far downstream of the bed surface. These observations indicate significant changes from established one phase flow modes. Gas-phase velocity profiles were obtained for a 0.36 m high bed with the diffuser located far downstream of the bed surface. A single component Laser-Doppler Anemometer was used to measure the streamwise velocity component for four diffuser configurations (straight, 20/sup 0/, 40..pi.., and 60/sup 0/ full opening angles), with and without the bed. The general structure of the freeboard flow was studied by introducing smoke into the bed. None of the diffusers exhibited separation effects in the presence of the bed.

  20. Analysis of a coal fired combined cycle with carried-heat gasification

    NASA Astrophysics Data System (ADS)

    Xu, Xiangdong; Zhu, Weimin; Zhao, Li; Fett, F. N.

    1994-12-01

    In the research of a more efficient, less costly, more environmentally responsible and less technically difficult method for generating electrical power from coal, the Carried-heat Gasification Combined Cycle (CGCC) is introduced by Tsinghua University. The high efficiency cycle includes carried-heat partial gasification, compressed air heating in a fluidized bed immersed air heater followed by a combustor and the heat recovery of gas turbine exhaust used as the combustion air for the differential-velocity atmospheric circulating fluidized bed (DFBC). Superheat steam is raised in the DFBC boiler. The comparison of results identifies the causes of performance difference between eight cases. Features of the cycle ensure a high coal conversion efficiency within current state of the art.

  1. Stable hydrogen production by methane steam reforming in a two zone fluidized bed reactor: Experimental assessment

    NASA Astrophysics Data System (ADS)

    Pérez-Moreno, L.; Soler, J.; Herguido, J.; Menéndez, M.

    2013-12-01

    The Two Zone Fluidized Bed Reactor concept is proposed for hydrogen production via the steam reforming of methane (SRM) including integrated catalyst regeneration. In order to study the effect of the contact mode, the oxidative SRM has been carried out over a Ni/Al2O3 catalyst using a fixed bed reactor (fBR), a conventional fluidized-bed reactor (FBR) and the proposed two-zone fluidized bed reactor (TZFBR). The technical feasibility of these reactors has been studied experimentally, investigating their performance (CH4 conversion, CO and H2 selectivity, and H2 global yield) and stability under different operating conditions. Coke generation in the process has been verified by several techniques. A stable performance was obtained in the TZFBR, where coke formation was counteracted with continuous catalyst regeneration. The viability of the TZFBR for carrying out this process with a valuable global yield to hydrogen is demonstrated.

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

    DOEpatents

    Lessor, Delbert L. (Richland, WA); Robertus, Robert J. (Richland, WA)

    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.

  3. 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.

  4. 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

  5. Combustion characteristics of paper and sewage sludge in a pilot-scale fluidized bed.

    PubMed

    Yu, Yong-Ho; Chung, Jinwook

    2015-01-01

    This study characterizes the combustion of paper and sewage sludge in a pilot-scale fluidized bed. The highest temperature during combustion within the system was found at the surface of the fluidized bed. Paper sludge containing roughly 59.8% water was burned without auxiliary fuel, but auxiliary fuel was required to incinerate the sewage sludge, which contained about 79.3% water. The stability of operation was monitored based on the average pressure and the standard deviation of pressure fluctuations. The average pressure at the surface of the fluidized bed decreased as the sludge feed rate increased. However, the standard deviation of pressure fluctuations increased as the sludge feed rate increased. Finally, carbon monoxide (CO) emissions decreased as oxygen content increased in the flue gas, and nitrogen oxide (NOx) emissions were also tied with oxygen content. PMID:26061904

  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

    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.

  7. 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.

  8. Sulfur dioxide control: Sulfur dioxide from coal burning sources. (Latest citations from the NTIS Bibliographic database). Published Search

    SciTech Connect

    Not Available

    1993-09-01

    The bibliography contains citations concerning air pollution control technology and various methods for desulfurization of coal combustion streams. Examples include fluidized bed and other combustion modifications, and the removal of sulfur dioxide from flue gas. Proper monitoring of the effluent to meet the established atmospheric standards is also discussed. Applications in powerplants, steam boilers, furnaces, kilns, and gas turbines are presented. (Contains 250 citations and includes a subject term index and title list.)

  9. Signatures of glass formation in a fluidized bed of hard spheres

    E-print Network

    Daniel I. Goldman; Harry L. Swinney

    2006-03-10

    We demonstrate that a fluidized bed of hard spheres during defluidization displays properties associated with formation of a glass. The final state is rate dependent, and as this state is approached, the bed exhibits heterogeneity with increasing time and length scales. The formation of a glass results in the loss of fluidization and an arrest of macroscopic particle motion. Microscopic motion persists in this state, but the bed can be jammed by application of a small increase in flow rate. Thus a fluidized bed can serve as a test system for studies of glass formation and jamming.

  10. 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.

  11. 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.

  12. A Fluidized Bed Chiller: A New Approach in Making Slush-Ice 

    E-print Network

    Klaren, D. G.; Van Der Meer, J. S.

    1991-01-01

    by Sunwell. Their evapor ator (called turbulator) consists of a fast rotating cylinder in a static cyl inder. The gap between the outer and inner (rotating) cylinder is small and the shear stress in this gap should prevent built up of ice crystals... crystals behave in solution. 3. THE FLUIDIZED BED CHILLER 3.1. History Already in the early eighties Klaren has been involved in experiments which proved that indeed slush-ice could be made in a fluidized bed chiller. 24 The liquid which causes...

  13. Characterization of Biofilm in 200W Fluidized Bed Reactors

    SciTech Connect

    Lee, Michelle H.; Saurey, Sabrina D.; Lee, Brady D.; Parker, Kent E.; Eisenhauer, Emalee ER; 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 evaluations, a more complete understanding of the balance between system additions (nutrients, groundwater) and biology can be achieved, thus increasing long-term predictions of performance. These analyses uniquely provide information that can be used in optimizing the overall performance, efficiency, and stability of the system both in real time as well as over the long-term, as the system design is altered or improved and/or new streams are added.

  14. Numerical Modeling of Reactive Multiphase Flow for FCC and Hot Gas Desulfurization Circulating Fluidized Beds

    SciTech Connect

    2005-07-01

    This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidized bed and in the process indentifying the parameters that affect the performance of the sulfidation reactor. Two different gas-solid reaction models, the unreacted shrinking core (USC) and the grain model were applied to take into account chemical reaction resistances. Also two different approaches were used to affect the hydrodynamics of the process streams. The first model takes into account the effect of micro-scale particle clustering by adjusting the gas-particle drag law and the second one assumes a turbulent core with pseudo-steady state boundary condition at the wall. A comparison is made with experimental results.

  15. 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.

  16. Proceedings of the conference on Coal Feeding Systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Development of coal feed systems for coal gasification, fluidized bed combustion, and magnetohydrodynamic applications is discussed. Process operations experience, energy conversion efficiency, and environment effects are among the factors considered.

  17. 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...

  18. Apparatus for feeding fluidized bed incinerator, and method of autogenic operation of same

    SciTech Connect

    Nelson, J.F.

    1981-09-29

    This invention relates to an improved method and apparatus for continuous autogenic incineration of high-moisture easily friable combustible agglomerates in a fluidized-bed. The improvement comprises introducing the waste materials into the bed in a tube of air provided by supplemental air means which surrounds the in-bed feed means.

  19. Transformation of chalcopyrite in the roasting process of copper concentrate in fluidized bed reactor

    NASA Astrophysics Data System (ADS)

    Coci?, Mira B.; Logar, Mihovil M.; Coci?, Saša Lj.; Devi?, Snežana S.; Manasijevi?, Dragan M.

    2011-05-01

    This work presents the results of investigation process of copper concentrate roasting in fluidized bed reactor with the aim of studying the transformations of copper concentrate minerals as well as to check the accordance with theoretical predictions. The roasted samples were examined using chemical analysis, x-ray diffraction, and mineral microscopy.

  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 ...