Science.gov

Sample records for atmospheric fluidized-bed coal

  1. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1992-08-01

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

  2. 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.

  3. 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.

  4. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1992-05-01

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

  5. 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.

  6. Fluidized bed combustion of coal

    NASA Astrophysics Data System (ADS)

    Tatebayashi, J.; Okada, Y.; Yano, K.; Takada, T.; Handa, K.

    The effect of various parameters on combustion efficiency, desulfurization efficiency and NO emission in fluidized bed combustion of coal were investigated by using two test combustors whose sectional areas were 200 mm and 500 mm square. It has been revealed that by employing two-stage combustion and setting the primary air ratio, secondary air injection height and other parameters to optimum levels, NO emission can be greatly reduced while barely impairing combustion efficiency or desulfurization efficiency. Also, NO emission of less than 50 ppm and desulfurization efficiency of as high as 93% were achieved. These results have ensured good prospects for the development of a coal combustion boiler system which can satisfy the strictest environmental protection regulations, without installing special desulfurization and de-NO(X) facilities.

  7. Fluidized bed coal combustion reactor

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  8. Pulsed atmospheric fluidized bed combustor apparatus

    SciTech Connect

    Mansour, Momtaz N.

    1993-10-26

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

  9. Simulation and modeling of atmospheric fluidized bed combustors for high sulfur coals

    SciTech Connect

    Krishnan, R.P.; Daw, C.S.; Byrd, J.; Wells, J.W.

    1989-01-01

    This paper briefly summarizes the state-of-the-art in Atmospheric Fluidized Bed Combustion (AFBC) modeling and uses the Oak Ridge National Laboratory (ORNL)-Tennessee Valley Authority (TVA) AFBC steady-state model as an example to illustrate how some major modeling concerns have been addressed. Other recent models are briefly described and compared with the ORNL-TVA model. The reader is referred to the references cited for details on the assumptions and computational methods. 100 refs., 8 figs., 1 tab.

  10. Fluidized bed coal desulfurization. Final Report

    SciTech Connect

    Ravindram, M.

    1983-08-01

    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.

  11. 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.

  12. Fluidized bed selective pyrolysis of coal

    DOEpatents

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

    1992-01-01

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

  13. Plasma-Augmented Fluidized Bed Gasification of Sub-bituminous Coal in CO2-O2 Atmospheres

    NASA Astrophysics Data System (ADS)

    Lelievre, C.; Pickles, C. A.; Hultgren, S.

    2016-01-01

    The gasification of a sub-bituminous coal using CO2-O2 gas mixtures was studied in a plasma-augmented fluidized bed gasifier. Firstly, the coal was chemically characterized and the gasification process was examined using Thermogravimetric and Differential Thermal Analysis (TGA/DTA) in CO2, O2 and at a CO2 to O2 ratio of 3 to 1. Secondly, the equilibrium gas compositions were obtained using the Gibbs free energy minimization method (HSC Chemistry7). Thirdly, gasification tests were performed in a plasma-augmented fluidized bed and the off-gas temperatures and compositions were determined. Finally, for comparison purposes, control tests were conducted using a conventional fluidized bed coal gasifier and these results were compared to those achieved in the plasma-augmented fluidized bed gasifier. The effects of bed temperature and CO2 to O2 ratio were studied. For both gasifiers, at a given bed temperature, the off-gas compositions were in general agreement with the equilibrium values. Also, for both gasifiers, an experimental CO2 to O2 ratio of about 3 to 1 resulted in the highest syngas grade (%CO + %H2). Both higher off-gas temperatures and syngas grades could be achieved in the plasma-augmented gasifier, in comparison to the conventional gasifier. These differences were attributed to the higher bed temperatures in the plasma-augmented fluidized bed gasifier.

  14. Plasma-Augmented Fluidized Bed Gasification of Sub-bituminous Coal in CO2-O2 Atmospheres

    NASA Astrophysics Data System (ADS)

    Lelievre, C.; Pickles, C. A.; Hultgren, S.

    2016-01-01

    The gasification of a sub-bituminous coal using CO2-O2 gas mixtures was studied in a plasma-augmented fluidized bed gasifier. Firstly, the coal was chemically characterized and the gasification process was examined using Thermogravimetric and Differential Thermal Analysis (TGA/DTA) in CO2, O2 and at a CO2 to O2 ratio of 3 to 1. Secondly, the equilibrium gas compositions were obtained using the Gibbs free energy minimization method (HSC Chemistry®7). Thirdly, gasification tests were performed in a plasma-augmented fluidized bed and the off-gas temperatures and compositions were determined. Finally, for comparison purposes, control tests were conducted using a conventional fluidized bed coal gasifier and these results were compared to those achieved in the plasma-augmented fluidized bed gasifier. The effects of bed temperature and CO2 to O2 ratio were studied. For both gasifiers, at a given bed temperature, the off-gas compositions were in general agreement with the equilibrium values. Also, for both gasifiers, an experimental CO2 to O2 ratio of about 3 to 1 resulted in the highest syngas grade (%CO + %H2). Both higher off-gas temperatures and syngas grades could be achieved in the plasma-augmented gasifier, in comparison to the conventional gasifier. These differences were attributed to the higher bed temperatures in the plasma-augmented fluidized bed gasifier.

  15. 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.

  16. 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.

  17. Gas distributor for fluidized bed coal gasifier

    DOEpatents

    Worley, Arthur C.; Zboray, James A.

    1980-01-01

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

  18. 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.

  19. 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.

  20. 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.

  1. (Pulsed atmospheric fluidized bed combustion (PAFBC))

    SciTech Connect

    Not Available

    1988-10-01

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

  2. Fluidized bed injection assembly for coal gasification

    DOEpatents

    Cherish, Peter; Salvador, Louis A.

    1981-01-01

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

  3. Atmospheric fluidized bed combustion advanced concept system

    SciTech Connect

    Not Available

    1992-05-01

    DONLEE Technologies Inc. is developing with support of the US Department of Energy an advanced circulating fluidized bed technology known as the Vortex{trademark} Fluidized Bed Combustor (VFBC). The unique feature of the VFBC is the injection of a significant portion of the combustion air into the cyclone. Since as much as one-half of the total combustion air is injected into the cyclone, the cross-sectional area of the circulating fluidized bed is considerably smaller than typical circulating fluidized beds. The technology is being developed for two applications: Industrial-scale boilers ranging from 20,000 to 100,000 pounds per hour steam generating capacity; and two-stage combustion in which a substoichiometric Vortex Fluidized Bed Combustor (2VFBC) or precombustor is used to generate a combustible gas for use primarily in boiler retrofit applications. This Level II analysis of these two applications indicates that both have merit. An industrial-scale VFBC boiler (60,000 lb/hr of steam) is projected to be economically attractive with coal prices as high as $40 per ton and gas prices between $4 and $5 per thousand cubic feet. The payback time is between 3 and 4 years. The 2VFBC system was evaluated at three capacities of application: 20,000; 60,000 and 100,000 lb/hr of steam. The payback times for these three capacities are 4.5, 2.1 and 1.55 years, respectively. The 2VFBC has potential applications for retrofit of existing pulverized coal-fired boilers or as a new large (utility) boiler. Pressurized operation of the 2VFBC has considerable potential for combined cycle power generation applications. Experimental development of both applications is presented here to demonstrate the potential of these two technologies.

  4. 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)

  5. 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.

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

    SciTech Connect

    Not Available

    1992-08-01

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

  7. 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)

  8. Steam generator with circulating atmospheric fluidized bed combustion

    NASA Astrophysics Data System (ADS)

    Wein, W.; Hoeffgen, H.; Maintok, K. H.; Daradimos, G.

    1982-08-01

    The combustion of coal in power plants by conventional combustion techniques is studied with emphasis on combustion in a circulating atmospheric fluidized bed (CFBC). The CFBC method stays half way between the classical fluidized bed with a well defined bed height and the pneumatic transport where particles and fluidizing gas have the same velocity. The main advantages of CFBC are: flexibility with respect to coal types; easy elimination of 80% of sulfur by mixing the coal with calcium carbonate to a molecular ratio Ca/S of about two; reduced nitrogen oxides production due to the low combustion temperature of 900 C; high steam production efficiency with the combustion degree exceeding 99%; high overall efficiency with no further desulfurizing being needed; easy regulation; high heat transmission rates (350 to 400 W/m2K) reducing exchange surfaces; small boiler building; and the possibility to build in one module a 300 MW unit.

  9. Pulsed atmospheric fluidized bed combustor apparatus and process

    DOEpatents

    Mansour, Momtaz N.

    1992-01-01

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

  10. International energy technology assessment: Atmospheric fluidized-bed combustion

    NASA Astrophysics Data System (ADS)

    Krishnan, R. P.; Johnsson, K. O.

    1982-04-01

    A survey was made of atmospheric fluidized bed combustion (AFBC) research and development and commercial activities in foreign countries. These activities indicate a broad interest in the process largely because of its flexibility in burning a wide range of coals and low grade fuels. The conclusion is made that AFBC is a viable system and is in the process of being confirmed on a commercial scale for industrial heat and power generation. A number of organizations in the United States and western Europe are offering fluidized bed package boilers, with some form of commercial guarantees. The major uncertainties of the process lie in the areas of coal and sorbent handling systems, availability of reliable construction materials; the system's ability to meet varying load demands; reduced sorbent requirements; and improved carbon utilization. Research and development programs in these areas are being pursued.

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. Polycyclic aromatic compounds in fluidized bed combustion of coal

    SciTech Connect

    Walsh, P.M.; Beer, J.M.; Biermann, K.; Chiu, K.S.

    1983-08-01

    Polycyclic aromatic compounds (PAC) have been determined in the gas and particulate effluents from fluidized bed combustion of coal, lignite, and oil shale by a number of investigators. A bibliography of the reports of these investigations is contained in a paper by Chiu, Walsh, Beer, and Biemann (1983). The concentrations of PAC in the effluents are often quite low, but depend upon the combustor configuration and operating conditions. The goal of the present investigation is to develop a mechanism consistent with measured rates of formation and destruction of PAC in atmospheric pressure fluidized bed combustion (AFBC), so that a rational approach may be taken to adjustment of conditions for minimization of PAC in the effluents. PAC are determined in samples taken from the freeboard (space above the bed), rather than from the exhaust, to observe the evolution of the PAC distribution within the combustor. Mass fractions of the most abundant PAC observed in the freeboard during AFBC of high volatile bituminous coal were reported by Chiu, et al (1983). Some correlation of the rates of disappearance of PAC with particle concentration was noted by Dutta, Chiu, Walsh, Beer, and Biemann (1983). In the present paper theoretical estimates of the rates at which PAC might be consumed by heterogeneous reactions are compared with experimental rates estimated from PAC profiles determined by Chiu et al (1983).

  16. 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...

  17. MATHEMATICAL MODEL FOR A FLUIDIZED-BED COAL GASIFIER

    EPA Science Inventory

    The report gives results of gasifying four fuels--a devolatilized Kentucky bituminous coal, a New Mexico subbituminous coal, a North Carolina peat, and a Texas lignite--with steam and oxygen in a pilot-scale fluidized-bed reactor. Experimental results were used to provide an eval...

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

    DOEpatents

    Hosek, William S.; Garruto, Edward J.

    1984-01-01

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

  19. 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.

  20. 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.

  1. Inclined fluidized bed system for drying fine coal

    DOEpatents

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

    1992-02-11

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

  2. Update of the Black Dog atmospheric fluidized bed combustion project

    SciTech Connect

    Osthus, D.; Larva, J.; Rens, D. )

    1988-01-01

    Northern States Power Co. converted its Black Dog Unit 2, a pulverized coal-fired 100 MW unit that was built in 1954, to an atmospheric fluidized bed (bubbling bed) configuration, in order to commercially demonstrate AFBC technology as a cost-effective way to reduce SO2 emissions. As part of the AFBC conversion, the unit was upgraded to 130 MW capacity. Unit 2 burns Western coal, is equipped with electrostatic precipitators, and cycles on and off line daily. The innovative nature of this project contributed to a protracted encountered. These problems are discussed. Many of the problems have been solved, and the unit is now meeting most of the goals set for the project.

  3. Characterization of coals for circulating fluidized bed combustion by pilot scale tests

    SciTech Connect

    Lopez, L.A.; Cabanillas, A.C.; Becerra, J.O. de

    1995-12-31

    The major part of the Spanish coal supply is low range coal with both high ash (20--40%) and sulfur (1--8%) content. The use of this coal, by conventional combustion processes in power and industrial plants, implies a very high environmental impact. The Circulating Fluidized Bed Combustion process enables an efficient use of this coal. The Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas is carrying out a program with the intention of assisting companies in evaluating fuel quality impact, using atmospheric fluidized bed combustion. This paper reviews the major results of the fuel program in order to determine the fluidized bed combustion performance of four fuels. Two lignites, a bituminous coal and an anthracite. The two lignites have very high sulfur content (7% and 8%) but the sulfur is organic in one case and pyritic in the other. The bituminous coal and the anthracite have 1% and 2% sulfur content respectively and the sulfur is pyritic in these cases. In order to reduce the sulfur in the flue gases, a high calcium content limestone has been used as sorbent. The combustion trials have been done in a circulating fluidized bed pilot plant with a 200 mm inside diameter and a height of 6.5 m. The influence of temperature, fluidization velocity, oxygen excess, Ca/S ratio and coal properties have been studied in relation to the combustion efficiency, sulfur retention, CO and NO{sub x} emissions.

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

    DOEpatents

    Snell, George J.; Kydd, Paul H.

    1983-01-01

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

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

    SciTech Connect

    Not Available

    1991-10-01

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

  6. 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.

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

    DOEpatents

    Scott, Charles D.; Strandberg, Gerald W.

    1989-01-01

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

  8. 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.

  9. 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.

  10. Characterization of products from fluidized-bed combustion of coal.

    PubMed

    Bednarik, V; Vondruska, M; Sild, M; Vondruskova, E

    2000-11-01

    The technology of fluidized-bed combustion (FBC) of coal generates byproducts that have a series of unique characteristics and potential uses in technological practice. In this study, the products of fluidized-bed combustion (FBC-P) of coal derived from Moravian heat stations, a.s. Zlin, Cinergy Global Resources, Czech Republic, were characterized. Particular attention was paid to determining the chemical composition of FBC-P, the content of polycyclic aromatic hydrocarbons (PAHs) and toxic metals in the water leachates of these FBC-P, the content of unburned carbon, the capability of FBC-P to solidify with water and form a solid matrix, and the method for discovering optimum mixing water content for FBC-P solidification. The results suggest that one of the qualitatively more important means of utilizing FBC-P could be their application during solidification/stabilization (S/S) of wastes, particularly wastewater treatment sludges. PMID:11111336

  11. Atmospheric fluidized bed combustion advanced concept system. Final report

    SciTech Connect

    Not Available

    1992-05-01

    DONLEE Technologies Inc. is developing with support of the US Department of Energy an advanced circulating fluidized bed technology known as the Vortex{trademark} Fluidized Bed Combustor (VFBC). The unique feature of the VFBC is the injection of a significant portion of the combustion air into the cyclone. Since as much as one-half of the total combustion air is injected into the cyclone, the cross-sectional area of the circulating fluidized bed is considerably smaller than typical circulating fluidized beds. The technology is being developed for two applications: Industrial-scale boilers ranging from 20,000 to 100,000 pounds per hour steam generating capacity; and two-stage combustion in which a substoichiometric Vortex Fluidized Bed Combustor (2VFBC) or precombustor is used to generate a combustible gas for use primarily in boiler retrofit applications. This Level II analysis of these two applications indicates that both have merit. An industrial-scale VFBC boiler (60,000 lb/hr of steam) is projected to be economically attractive with coal prices as high as $40 per ton and gas prices between $4 and $5 per thousand cubic feet. The payback time is between 3 and 4 years. The 2VFBC system was evaluated at three capacities of application: 20,000; 60,000 and 100,000 lb/hr of steam. The payback times for these three capacities are 4.5, 2.1 and 1.55 years, respectively. The 2VFBC has potential applications for retrofit of existing pulverized coal-fired boilers or as a new large (utility) boiler. Pressurized operation of the 2VFBC has considerable potential for combined cycle power generation applications. Experimental development of both applications is presented here to demonstrate the potential of these two technologies.

  12. 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.

  13. 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)

  14. 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)

  15. 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)

  16. Pyrometric temperature and size measurements of burning coal particles in a fluidized bed combustion reactor

    SciTech Connect

    Joutsenoja, T.; Heino, P.; Hernberg, R.; Bonn, B.

    1999-09-01

    The article reports on the application of fiber-optic two-color optical pyrometry to the measurement of temperature and size of combusting coal particles in an atmospheric fluidized bed combustion reactor. The utility of the measuring technique is that it makes possible nonintrusive in situ measurement of the dependence between the temperature and size of combusting fuel particles. The method allows the temperatures of the fluidized bed and individual fuel particles to be determined wherever these deviate from the bed temperature. Besides giving these temperatures, this method also allows for the statistical determination of the particle size distribution within the population of observed particles. The effects of bed temperature (1,130--1,200 K) and oxygen concentration (5--8 vol%) on the temperature of combusting Westerholt high volatile bituminous coal particles were studied in a laboratory-scale bubbling fluidized bed combustor. The average particle temperature exceeded the bed temperature by about 100--200 K, while the maximum particle temperatures were nearly 600 K above the bed temperature. The interrelation between the size (< 1.2 mm) and temperature of burning coal particles is presented.

  17. 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 ...

  18. EXPERIMENTAL STUDY OF HIGH LEVELS OF SO2 REMOVAL IN ATMOSPHERIC-PRESSURE FLUIDIZED-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...

  19. 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.

  20. Co-combustion of agricultural residues with coal in a fluidized bed combustor.

    PubMed

    Ghani, W A W A K; Alias, A B; Savory, R M; Cliffe, K R

    2009-02-01

    Power generation from biomass is an attractive technology that utilizes agricultural residual waste. In order to explain the behavior of biomass-fired fluidized bed incinerator, biomass sources from agricultural residues (rice husk and palm kernel) were co-fired with coal in a 0.15m diameter and 2.3m high fluidized bed combustor. The combustion efficiency and carbon monoxide emissions were studied and compared with those for pure coal combustion. Co-combustion of a mixture of biomass with coal in a fluidized bed combustor designed for coal combustion increased combustion efficiency up to 20% depending upon excess air levels. Observed carbon monoxide levels fluctuated between 200 and 900 ppm with the addition of coal. It is evident from this research that efficient co-firing of biomass with coal can be achieved with minimal modifications to existing coal-fired boilers. PMID:18614348

  1. Release of nitrogen precursors from coal and biomass residues in a bubbling fluidized bed

    SciTech Connect

    P. Abelha; I. Gulyurtlu; I. Cabrita

    2008-01-15

    This work was undertaken with the aim of quantifying the relative amounts of NH{sub 3} and HCN released from different residues during their devolatilization under fluidized bed conditions. The results were compared with data collected for bituminous coals of different origin. The relation between amounts of HCN and NH{sub 3} released and the levels of NOX and N{sub 2}O formed during cocombustion was also addressed. The partitioning of nitrogen between volatiles and char was also quantified. The pyrolysis studies were undertaken in a small fluidized bed reactor of 80 mm of ID and 500 mm high using an inert atmosphere (N{sub 2}). The HCN and NH{sub 3} were quantified by bubbling the pyrolysis gases in absorbing solutions which were subsequently analyzed with selective electrodes. The combustion studies were carried out on a pilot installation. The fluidized bed combustor is square in cross section with each side being 300 mm long. There is secondary air supply to the freeboard at different heights to deal with high volatile fuels as almost all waste materials are. The temperatures in the bed and in the freeboard and that of the flue gases leaving the reactor were continuously monitored. The results obtained suggest that, while coal releases nitrogen mostly as HCN, residues like RDF and sewage sludge give out fuel-N in greater quantities as NH{sub 3}. Residues at fluidized bed combustion (FBC) temperatures release more than 80% of the fuel-N with the volatiles. The NH{sub 3} evolved during pyrolysis acted as a reducing agent on NOX emissions. The presence of calcium significantly reduces the emission of N{sub 2}O probably by interfering with HCN chemistry. With high amounts of residues in the fuel mixture, the relative importance of char on the nitrogen chemistry substantially decreases. By using cocombustion, it is possible to reduce fuel-N conversion to NOX and N{sub 2}O, by tuning the amounts of coal and residue in the mixture. 29 refs., 18 figs., 3 tabs.

  2. Industrial coal-fired fluidized-bed demonstration program. Progress report, April 30-May 1, 1980

    SciTech Connect

    Accortt, J.I.; Comparato, J.R.; Norcross, W.R.

    1980-01-01

    Progress in the construction, now 35% complete, of an industrial fluidized bed steam generating plant being built at the US Navy Great Lakes Training Facility in Illinois is reported. This plant will provide a practical demonstration of the use of fluidized bed technology in an industrial coal fired application. It has been designed making use of the valuable data and experience gained from the operation and testing of the sub-scale fluidized bed boiler. The construction and shakedown are scheduled to be completed later this year and the formal test program to begin in 1981. The information to be provided from the test series will allow industry to assess the capabilities of fluidized bed combustion under meaningful operation conditions.

  3. 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...

  4. 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.

  5. Experimental investigations on brown coal drying in a pressurized steam fluidized bed

    SciTech Connect

    Buschsieweke, F.; Hannes, J.

    1999-07-01

    The development of new power plants based on brown coal, which has a raw moisture of up to 60 wt%, aims at a further improvement of the plant efficiency. The use of steam fluidized bed technique for a separate brown coal drying step is a promising possibility to reach this goal. The paper reports actual experimental results of parameter variations like pressure and particle size in a steam fluidized bed test dryer. For the used particle fractions, the particle convective mechanism is the leading factor for the overall heat transfer in steam fluidized bed drying of brown coal. An increase of pressure only enhances the negligible gas convective mechanism. Particle size reduction seems to be a promising measure to increase the overall heat transfer coefficient significantly.

  6. Agglomeration of sorbent and ash carry-over for use in atmospheric fluidized-bed combustors

    SciTech Connect

    Rohargi, N.D.T.

    1983-04-01

    Agglomeration of elutriated sorbent, ash and char from a fluidized-bed boiler, with spent bed overflow material and water, has been identified as a potentially attractive technique for reducing sorbent consumption in atmospheric fluidized-bed combustors. The agglomerated products are returned to the combustor to improve the calcium utilization of the sorbent and to complete the combustion of elutriated carbon material. In this experimental programme, agglomerates were collected during test runs on the 1.8 m x 1.8 m fluidized-bed combustor. Agglomerate characteristics, such as handling strength, sulfur capture activity carbon utilization and resistance to attrition, were determined as functions of agglomeration processing variables. These variables include feed composition, feed particle size, amount of water addition, curing time, and curing atmosphere or drying conditions. Ca/S feed ratio requirements for a commercial AFBC that uses the agglomeration process were projected on the basis of the Westinghouse model for fluidized-bed desulphurization.

  7. Fluidized bed combustion of low-grade coal and wastes: Research and development

    SciTech Connect

    Borodulya, V.A.; Dikalenko, V.I.; Palchonok, G.I.; Vinogradov, L.M.; Dobkin, S.M.; Telegin, E.M.

    1994-12-31

    Experimental studies were carried out to investigate devolatilization of fuel as single spherical particles of wood, hydrolytic lignin, leather sewage sludge and Belarussian brown coals in a fluidized bed of sand. It is found that the devolatilization process depends on moisture and ash contents in fuel and on the external heat and mass transfer rate. The char combustion occurs largely in the intermediate region. Kinetic parameters of the devolatilization and char combustion are obtained. A low-capacity fluidized bed boiler suitable for combustion of coal and different wastes is described.

  8. 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...

  9. 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...

  10. 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.

  11. 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.

  12. 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.

  13. Fluidized bed combustion of solid organic wastes and low-grade coals: Research and modeling

    SciTech Connect

    Borodulya, V.A.; Dikalenko, V.I.; Palchonok, G.I.; Stanchits, L.K.

    1995-12-31

    Experimental studies were carried out to investigate devolatilization and combustion of single spherical particles of wood, hydrolytic lignin from ethanol production, leather processing sewage sludge, and low-grade Belarusian brown coals in a fluidized bed of sand. A two-phase model of fluidized bed combustion of biowaste is proposed. The model takes into account combustion of both volatiles and char in the bed as well as in the freeboard. Experimentally obtained characteristics of devolatilization and char combustion are used as parameters of the model proposed.

  14. 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...

  15. 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...

  16. 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...

  17. 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.

  18. Development of an advanced process for drying fine coal in an inclined fluidized bed

    SciTech Connect

    Boysen, J.E.; Cha, C.Y.; Barbour, F.A.; Turner, T.F.; Kang, T.W.; Berggren, M.H.; Hogsett, R.F.; Jha, M.C.

    1990-02-01

    The objective of this research project was to demonstrate a technically feasible and economically viable process for drying and stabilizing high-moisture subbituminous coal. Controlled thermal drying of coal fines was achieved using the inclined fluidized-bed drying and stabilization process developed by the Western Research Institute. The project scope of work required completion of five tasks: (1) project planning, (2) characterization of two feed coals, (3) bench-scale inclined fluidized-bed drying studies, (4) product characterization and testing, and (5) technical and economic evaluation of the process. High moisture subbituminous coals from AMAX Eagle Butte mine located in the Powder River Basin of Wyoming and from Usibelli Coal Mine, Inc. in Healy, Alaska were tested in a 10-lb/hr bench-scale inclined fluidized-bed. Experimental results show that the dried coal contains less than 1.5% moisture and has a heating value over 11,500 Btu/lb. The coal fines entrainment can be kept below 15 wt % of the feed. The equilibrium moisture of dried coal was less than 50% of feed coal equilibrium moisture. 7 refs., 60 figs., 47 tabs.

  19. 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.

  20. 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.

  1. Materials problems in fluidized-bed-combustion and coal-gasification systems: Further studies of corrosion chemistry in low-oxygen activity atmospheres

    NASA Astrophysics Data System (ADS)

    Perkins, R. A.; Coons, W. C.; Vonk, S. J.

    1982-06-01

    The results of studies on corrosion chemistry in low-oxygen activity atmospheres that are characteristic of gasified or incompletely combusted coal are given. The objective was to identify those factors in alloy composition and structure and in gas composition and temperature that govern both the formation and eventual breakdown of protective-oxide scales in low-P sub O 2 to high-P sub S 2 atmospheres. It was found that protective chromic-oxide scales of uniform composition and structure formed only on cold-worked or ultrafine grain surfaces of alloys containing more than one percent Fe or Mn. Breakdown or failure of normally protective chromic-oxide scales was studied as a function of alloy composition (Fe, Ni, Co, Mn, Cr) and atmosphere conditions. The most protective scales were those formed on Ni-Cr alloys low in Fe and Mn. These scales failed eventually by mechanical breakdown; i.e., cracking or spalling.

  2. Coal gasification in fluidized bed combustion: Status and developments - Future perspectives

    NASA Astrophysics Data System (ADS)

    Staege, H.

    1980-07-01

    The state of the art of fluidized bed combustion is surveyed. Attention is given to the steps in the process such as preparation of the coal, gasification of the coal dust, waste heat recycling, cooling, and removing of particulates, and treatment of the recirculating water. Also discussed are removal of sulfur from the gas, developments of the principle such as the Shell-Kopper process, Saarberg-Otto process, and the Texaco-process.

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

    SciTech Connect

    Jack A. Fuller; Harvie Beavers; Robert Bessette

    2006-06-15

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

  4. Pulsed atmospheric fluidized bed combustion. Technical progress report, January 1992--March 1992

    SciTech Connect

    Not Available

    1992-05-01

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

  5. [Pulsed atmospheric fluidized bed combustion (PAFBC)]. Technical progress report, May--July 1988

    SciTech Connect

    Not Available

    1988-10-01

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

  6. Some special features of combusting the coal-water fuel made of Belarussian brown coals in the fluidized bed

    NASA Astrophysics Data System (ADS)

    Borodulya, V. A.; Buchilko, E. K.; Vinogradov, L. M.

    2014-07-01

    This paper deals with the special features of combusting the coal-water fuel prepared on the basis of Belarussian brown coals and anthracite culm (Ukraine) in a fluidized bed. The sequence and the duration (calculated from the mathematical model being suggested) of the stages of the combustion of the coal-water fuel depending on the type of source solid fuel and fluidized bed temperature were experimentally confirmed. The temperature and time dependences of the content of sulfur, nitrogen, and carbon oxides in flue gases were studied.

  7. Toxicological effects on mice following inhalation exposures to fluidized-bed coal combustor fly ash

    SciTech Connect

    Kirchner, F.R.; Reilly, C.A. Jr.; Buchholz, D.M.; Pahnke, V.A. Jr.

    1983-12-01

    Toxicological effects of exposure to reaerosolized fly ash from a fluidized-bed coal combustor were evaluated in mice following 500- and 1000-hr inhalation exposures. Alveolar macrophage function, organ histology, and hematopoiesis were assessed following 24-hr/day exposures in two 500-hr experiments. There was little mutagenicity detected by the Ames assay in the samples of the fly ash tested. The chemical characteristics of the fly ash were very similar to those of fly ash produced during conventional coal combustion. However, physical characterization revealed that fluidized-bed combustion fly ash was not fused as is commonly the case in conventionally combusted fly ash, and as a result had a very large surface area. The function of the alveolar macrophages of exposed mice was impaired, and there were significant changes in the histology of the lung, including cellular infiltration and hyperplasia of bronchiolar and alveolar epithelium. These changes are characteristic of pulmonary responses to chronic irritation of the lung.

  8. Toxicological effects on mice following inhalation exposures to fluidized-bed coal combustor fly ash

    SciTech Connect

    Kirchner, F.R.; Reilly, C.A. Jr.; Buchholz, D.M.; Pahnke, V.A. Jr.

    1983-01-01

    Toxicological effects of exposure to reaerosolized fly ash from a fluidized-bed coal combustor were evaluated in mice following 500- and 1000-hr inhalation exposures. Alveolar macrophage function, organ histology, and hematopoiesis were assessed following 24-hr/day exposures in two 500-hr experiments. There was little mutagenicity detected by the Ames assay in the samples of the fly ash tested. The chemical characteristics of the fly ash were very similar to those of fly ash produced during conventional coal combustion. However, physical characterization revealed that the fluidized-bed combustion fly ash was not fused as is commonly the case in conventionally combusted fly ash, and as a result had a very large surface area. The function of the alveolar macrophages of exposed mice was impaired, and there were significant changes in the histology of the lung, including cellular infiltration and hyperplasia of bronchiolar and alveolar epithelium. These changes are characteristic of pulmonary responses to chronic irritation of the lung.

  9. Materials problems in fluidized-bed-combustion and coal-gasification systems: further studies of corrosion chemistry in low-oxygen activity atmospheres. Final report

    SciTech Connect

    Perkins, R.A.; Coons, W.C.; Vonk, S.J.

    1982-06-01

    This report presents the results of additional studies on corrosion chemistry in low-oxygen activity atmospheres that are characteristic of gasified or incompletely combusted coal. The objective of the work was to identify those factors in alloy composition and structure and in gas composition and temperature that govern both the formation and eventual breakdown of protective-oxide scales in low-P/sub O//sub 2// to high-P/sub S//sub 2// atmospheres. It was found that protective chromic-oxide scales of uniform composition and structure formed only on cold-worked or ultrafine grain surfaces of alloys containing >1% Fe or Mn. Breakdown or failure of normally protective chromic-oxide scales was studied as a function of alloy composition (Fe, Ni, Co, Mn, Cr) and atmosphere conditions (P/sub O//sub 2//, P/sub S//sub 2// temperature). The most protective scales were those formed on Ni-Cr alloys low in Fe and Mn (<1%). These scales failed eventually by mechanical breakdown; i.e., cracking or spalling. The least-protective scales were those formed on alloys containing Fe and Mn. Internal sulfidation did not appear to be a major factor in breakaway sulfidation of alloys. Chromic-oxide scales formed in the absence of sulfur were found to be excellent barriers to the inward transport of sulfur. It is concluded that the best alloys for resisting sulfidation in these atmospheres are Ni or Co-Ni based with 30 to 50% Cr and <0.1% Fe and Mn. Yttrium or rare earths should be added to reduce the rate of oxide growth and to retard failure by oxide cracking or spalling.

  10. CONTROL OF PARTICULATE EMISSIONS FROM ATMOSPHERIC FLUIDIZED-BED COMBUSTION WITH FABRIC FILTERS AND ELECTROSTATIC PRECIPITATORS

    EPA Science Inventory

    The report gives results of a study of chemical and physical characteristics affecting the performance of particulate control equipment, based on five fly ash samples from full- and pilot-scale atmospheric fluidized-bed combustion (AFBC) units. Analysis of acquired data by fabric...

  11. 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

  12. Temperatures of coal particle during devolatilization in fluidized bed combustion reactor

    SciTech Connect

    Komatina, M.; Manovic, V.; Saljnikov, A.

    2006-11-15

    The purpose of this study was to investigate the thermal behavior of coal during devolatilization in fluidized bed. Temperatures in the center of single coal particle were measured by thermocouple. Two coals were tested (brown coal Bogovina and lignite Kosovo), using dry coal particle, shaped into spherical form of diameters 7 and 10 mm, in temperature range from 300 to 850{sup o}C. Unsteady behavior of coal particle during heating and devolatilization in fluidized bed was described by a model that takes into account heat transfer between bed and particle surface, heat transfer through particle and an endothermic chemical reaction of first-order. Based on the mathematical model analysis and compared with experimental results, values of heat conductivity {lambda}{sub C} and heat capacity (C-p) of coal were determined. The best agreement was obtained for constant thermal properties, for brown coal {lambda}{sub C} = 0.20 W/mK and C{sub p} = 1200 J/kgK and for lignite {lambda}{sub C} = 0.17 W/mK and C-p = 1100 J/kgK.

  13. Fluidized bed boiler feed system

    DOEpatents

    Jones, Brian C.

    1981-01-01

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

  14. Emissions of N{sub 2}O in fluidized bed combustion of coal

    SciTech Connect

    Lin, M.; Kulasekaran, S.; Ignowski, J.M.; Linjewile, T.M.; Agarwal, P.K.

    1999-07-01

    This study presents a new approach for examination of the mechanisms of formation and destruction of N{sub 2}O in single char spheres burning in an incipiently fluidized bed, which is thought to represent the emulsion phase of a bubbling bed. Char particles from three commercially available coals were investigated. These included a subbituminous coal from the Skull coal mine in Kemmerer, Wyoming; a bituminous coal from the Hanna basin in Wyoming; and a subbituminous coal from the Cyprus Foidel Creek mine in Colorado. A spherical char particle 12 mm in diameter, embedded with a thermocouple in its center, was attached to the tip of a gas-sampling probe. The char-probe assembly was immersed into the center of a hot incipiently fluidized bed. Combustion gases escaping from the surface of the burning char particle were sampled and analyzed for N{sub 2}O, NO, NO{sub 2}, CO, and CO{sub 2} as a function of time by means of a Fourier Transform Infrared (FTIR) Spectrometer. In addition, combustion of batches of char was conducted in the fluidized bed operated in a bubbling mode. Both single particle and batch combustion experiments were conducted using silica sand particles of 200 and 1,000 {micro}m size at bed temperatures ranging from 773 to 1,173 K. Operating variables which influence particle temperature and, hence the rates of formation and destruction of N{sub 2}O and NO, were examined. Char particle temperature, observed to be up to 400 K higher than the bed temperature, was found to be the principal influence on the emissions of both N{sub 2}O and NO{sub x}. In combustion of batches, emissions of N{sub 2}O seemed to depend not only on the bed temperature, but also on the initial char particle size.

  15. 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.

  16. Hybrid fluidized bed combuster

    DOEpatents

    Kantesaria, Prabhudas P.; Matthews, Francis T.

    1982-01-01

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

  17. Co-firing of paper mill sludge and coal in an industrial circulating fluidized bed boiler.

    PubMed

    Tsai, Meng-Yuan; Wu, Keng-Tung; Huang, Chin-Cheng; Lee, Hom-Ti

    2002-01-01

    Co-firing of coal and paper mill sludge was conducted in a 103 MWth circulating fluidized bed boiler to investigate the effect of the sludge feeding rate on emissions of SOx, NOx, and CO. The preliminary results show that emissions of SOx and Nx decrease with increasing sludge feeding rate, but CO shows the reverse tendency due to the decrease in combustion temperature caused by a large amount of moisture in the sludge. All emissions met the local environmental requirements. The combustion ashes could be recycled as feed materials in the cement manufacturing process. PMID:12099502

  18. Fluidized bed pyrolysis of bitumen-impregnated sandstone at sub-atmospheric conditions

    SciTech Connect

    Fletcher, J.V.; Deo, M.D.; Hanson, F.V.

    1993-01-01

    A 15.2 cm diameter fluidized bed reactor was designed, built, and operated to study the pyrolysis of oil sands at pressures slightly less than atmospheric. Fluidizing gas flow through the reactor was caused by reducing the pressure above the bed with a gas pump operating in the vacuum mode. Pyrolysis energy was supplied by a propane burner, and the hot propane combustion gases were used for fluidization. The fluidized bed pyrolysis at reduced pressure using combustion gases allowed the reactor to be operated at significantly lower temperatures than previously reported. At 450[degree], over 80% of the bitumen fed was recovered as a liquid product, and the spent sand contained less than 1% coke. The liquid product recovery system, by design, yielded three liquid streams with distinctly different properties.

  19. Fluidized bed pyrolysis of bitumen-impregnated sandstone at sub-atmospheric conditions

    SciTech Connect

    Fletcher, J.V.; Deo, M.D.; Hanson, F.V.

    1993-03-01

    A 15.2 cm diameter fluidized bed reactor was designed, built, and operated to study the pyrolysis of oil sands at pressures slightly less than atmospheric. Fluidizing gas flow through the reactor was caused by reducing the pressure above the bed with a gas pump operating in the vacuum mode. Pyrolysis energy was supplied by a propane burner, and the hot propane combustion gases were used for fluidization. The fluidized bed pyrolysis at reduced pressure using combustion gases allowed the reactor to be operated at significantly lower temperatures than previously reported. At 450{degree}, over 80% of the bitumen fed was recovered as a liquid product, and the spent sand contained less than 1% coke. The liquid product recovery system, by design, yielded three liquid streams with distinctly different properties.

  20. Numerical Simulation of Sludge Dryness under Flue Gas Atmosphere in the Riser of a Fluidized Bed

    NASA Astrophysics Data System (ADS)

    Xiao, H. M.; Ma, X. Q.; Liu, K.; Yu, Z. S.

    A numerical algorithm is developed for a detailed 3D simulation of the gas/particle flow behavior used for drying of sludge under flue gas atmosphere in the riser section of a circulating fluidized bed. The gas phase is described with standard κ - ɛ turbulence model, whereas a Lagrangian formulation with a stochastic particle dispersion model is adopted for the particulate phase. Conservation equations of mass and momentum for each phase were solved using the volume numerical technique. Fluid-particle interaction is taken into account to calculate the mass, momentum, and heat transfer between phases. The numerical algorithm is used to predict the circulating fluidized bed performance under various inlet profiles of the flue gas velocity. Gas and particle flow profiles were obtained for velocity and temperature parameters for each phase. The influence of the flue gas inlet velocity and the sludge mass flow rate on drying is discussed.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Interim operations report for atmospheric fluidized-bed combustion conversion at Northern States Power Company

    SciTech Connect

    Thimsen, D. )

    1991-03-01

    Northern States Power Company converted its Black Dog Station Unit No. 2 boiler from a front wall fired pulverized coal boiler to a bubbling atmospheric fluidized bed combustor (AFBC) boiler. The resulting unit was uprated from 85 MWe to 130 MWe burning western subbituminous coal. This report describes the AFBC operating and maintenance experience in the startup period from initial operation in June 1986 through March 1989 when a turbine oil fire caused a forced outage of 8 months. A brief review of the construction history is given in Section 1. Section 2 chronicles the AFBC operation. Section 3 describes how the boiler is restarted under several conditions. The performance history of the systems in the AFBC that are peculiar to the AFBC process or directly impacted by the AFBC process are described in detail in Section 4. The AFBC conversion at the Black Dog station has met nearly all of the original design objectives: (1) The unit can operate at rated output of 130 MWe burning western subbituminous coal, (2) The design life of the unit has been extended 25 years, (3) It has been shown that the EPA New Source Performance Standards for NO{sub x} and SO{sub 2} can be met with no flue gas treatment, (4) Operators have conducted over 200 routine daily unit restarts confirming the ability of the unit to serve in daily cycling mode, and (5) A variety of fuels have been successfully burned in the AFBC. The only objective that remains partially achieved is routine operation at full load. The boiler/turbine/generator have been shown to be fully capable of operation at full load, but the electrostatic precipitators (which were largely unchanged during the retrofit) have been inadequate to allow full load operation while remaining within permitted opacity and particulate emissions. The unit is currently dispatched in daily cycling service and is limited to operation below 106 MWe by its emissions control permit. 12 refs., 34 figs., 6 tabs.

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

    NASA Astrophysics Data System (ADS)

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

    1996-11-01

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

  7. 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.

  8. Evaluation of dust cake filtration at high temperature with effluence from an atmospheric fluidized-bed combustor

    SciTech Connect

    Dennis, R.A.

    1990-08-01

    In the spring of 1989, two separate test series were simultaneously conducted at the US Department of Energy's (DOE's) Morgantown Energy Technology Center (METC) to examine applied and fundamental behavior of dust cake filtration under high temperature and high pressure (HTHP) conditions. The purpose was to provide information on dust-cake filtration properties to gas stream cleanup researchers associated with the Tidd 70 megawatt (MW) pressurized fluidized-bed combustor (PFBC). The two test facilities included (1) a high-pressure natural-gas combustor with injected particulate, which was fed to two full-size candle filters; and (2) an atmospheric fluidized-bed combustor (AFBC) with coal and limestone sorbent to generate a particulate-laden combustion exhaust gas, which was sent to a single full-size candle filter and a small-scale disc filter. Several major conclusions from these studies are noted below. On average reducing the mean particulate size by 33% and the associated loading carried in the filtrate will increase the dust cake specific flow resistance (K{sub 2}) by 498%. High-temperature and high-pressure filtration can be successfully performed with ceramic candle filters at moderate filtration face velocities and reasonable system pressure drops. Off-line filter cleaning can produce a filter system with a higher apparent permeability than that produced from on-line filter cleaning at the same face velocity. 19 refs., 89 figs., 13 tabs.

  9. Temporal measurements and kinetics of selenium release during coal combustion and gasification in a fluidized bed.

    PubMed

    Shen, Fenghua; Liu, Jing; Zhang, Zhen; Yang, Yingju

    2016-06-01

    The temporal release of selenium from coal during combustion and gasification in a fluidized bed was measured in situ by an on-line analysis system of trace elements in flue gas. The on-line analysis system is based on an inductively coupled plasma optical emission spectroscopy (ICP-OES), and can measure concentrations of trace elements in flue gas quantitatively and continuously. The results of on-line analysis suggest that the concentration of selenium in flue gas during coal gasification is higher than that during coal combustion. Based on the results of on-line analysis, a second-order kinetic law r(x)=0.94e(-26.58/RT)(-0.56 x(2) -0.51 x+1.05) was determined for selenium release during coal combustion, and r(x)=11.96e(-45.03/RT)(-0.53 x(2) -0.56 x+1.09) for selenium release during coal gasification. These two kinetic laws can predict respectively the temporal release of selenium during coal combustion and gasification with an acceptable accuracy. Thermodynamic calculations were conducted to predict selenium species during coal combustion and gasification. The speciation of selenium in flue gas during coal combustion differs from that during coal gasification, indicating that selenium volatilization is different. The gaseous selenium species can react with CaO during coal combustion, but it is not likely to interact with mineral during coal gasification. PMID:26897573

  10. Hot corrosion of B-1900 superalloy by simulated fluidized bed coal combustor deposits

    SciTech Connect

    Stewart, S.F.C.; Shatynski, S.R.

    1982-10-01

    Calcium sulfate deposits in fluidized bed coal combustors are thought to contribute to heat transfer tube hot corrosion observed in test beds. Although Na/sub 2/SO/sub 4/ caused catastrophic hot corrosion of B-1900 superalloy at 900/sup 0/C in air, the corrosion due to CaSO/sub 4//Na/sub 2/SO/sub 4/ mixtures resembled that of simple oxidation, both in scale appearance and kinetics. High scale calcium content suggested a solid state reaction with CaSO/sub 4/ that did not compromise the protective scale. Although trace vanadium pentoxide added to a high percentage CaSO/sub 4/ mixture was shown to be innocuous, trace lead oxide caused catastrophic hot corrosion. However, the mechanism is unknown. This suggests that the latter coal impurity warrants attention as a possible severe corrosive threat, although CaSO/sub 4/ itself appears innocuous in an oxidizing environment.

  11. Trace metal capture by various sorbents during fluidized bed coal combustion

    SciTech Connect

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

    1996-06-01

    Experiments were conducted in a 1-in. quartz fluidized bed combustor enclosed in an electric furnace. Coal samples were burned in the bed with a sorbent under specific combustion conditions and the amount of metal capture by the sorbent determined. Three different cao samples from the Illinois Basin Coal Sample Bank were tested. Metals involved were Cd, Pb, and Cr; the sorbents included bauxite, zeolite, and lime. Potential metal-sorbent reactions were identified. Results indicated that metal capture by sorbent can be as high as 96%, depending on the metal species and sorbent. All 3 sorbents were capable of capturing Pb, zeolite and lime were able to capture Cr, and bauxite was the only sorbent capable of capturing Cd. Thermodynamic equilibrium calculations suggested the formation of metal-sorbent compounds such as Pb{sub 2}SiO{sub 4}, CdAl{sub 2}O{sub 4}, and CdSiO{sub 3} solids under the combustion conditions.

  12. Technical challenges in the design and operation of a circulating fluidized bed combustor burning waste coal

    SciTech Connect

    Reed, M.R.; Dicker, J.M.; Gagliardi, C.R.; Sommerhalter, K.L.; Tsao, T.R.; Wang, S.I. )

    1992-01-01

    The Air Products Cambria Cogeneration facility, located in Cambria County, Pennsylvania, was designed to burn 90 ton/hr bituminous coal refuse (gob) - a waste by-product from a coal preparation plant, in two circulating fluidized bed (CFB) combustors, producing a net power output of 85 MW to Pennsylvania Electric Company and u to 15,000 lb/hr of low pressure extraction steam to a nearby nursing home for building heating and laundry service. The facility was successfully started up in March 1991 and has consistently achieved high plant availability since April 1991. This paper will discuss a number of technical challenges which we have overcome in the Cambria Cogen facility as well as some notable accomplishments that have been achieved at the facility.

  13. 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.

  14. Analysis and characterization of atmospheric fluidized-bed-combustion agglomerates. Final report

    SciTech Connect

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

    1982-06-01

    The combustion of high-sodium low-rank coal in an Atmospheric Fluidized Bed Combustor (AFBC) can produce agglomeration of varying severity. Agglomerates and bed materials produced by a 0.2 m/sup 2/ AFBC were studied by polarized light microscopy, scanning electron microscopy, and electron microprobe analysis of thin sections. Bulk samples were studied using x-ray diffraction and x-ray fluorescence techniques. A physio-chemical or geochemical approach was used to characterize the materials and to postulate a mechanism of formation of the agglomerates. Quartz bed materials typically have nodular ash coatings with a matrix of finer sulfate ash richer in calcium and sulfur. Quartz bed agglomerates have additional calcium-rich sulfur-poor glass binding the grains together. Limestone bed materials typically have nodular ash coatings and have concentric alteration zones of calcium-rich areas with additional sulfur, iron, and sodium. Limestone agglomerates have additional sulfation and masses of coarse CaSO/sub 4/ crystals. Agglomerate formation in quartz bed materials follows a 4-stage process: an initial ash coating of about 50 microns thickness; thickened nodular coatings and initial sulfation; initial agglomeration by a cement of sulfated aluminosilicate ash; and bonding by recrystallized sulfated ash which has partly melted and solidified. Agglomerate formation in limestone bed materials follows a 3-stage process: initial bed grain alteration or calcining and sulfation producing concentric zones; thickened nodular ash coatings and continued sulfation; and agglomeration and growth of large CaSO/sub 4/ crystals. The agglomeration process is believed to be dependent upon temperature excursions caused by ash buildup in the bed with accompanying interaction between ash and bed material. Sodium appears to play a critical but presently largely unknown, role in the reactions producing agglomerates.

  15. Rotary regenerative heat exchanger: Application to atmospheric fluidized-bed combustion boilers

    SciTech Connect

    Gilkey, C.H.; Mergler, T.G.; Muller-Odenwald, H.; Francin, P.; Sakashita, Susumu

    1995-12-31

    The application of the Ljungstrom{reg_sign} air preheater, a rotary regenerative type, to atmospheric fluidized-bed combustion (AFBC) bubbling-bed and circulating-bed boilers is summarized. The air preheater is used to recover useful heat from the boiler exhaust gas and return it to the incoming combustion air. This provides a more efficient combustion process. Tubular and regenerative air preheaters are key accessories being used on AFBC boilers throughout the world. Descriptions in this paper will cover nine units in operation or planned. The projects include: USA`s Northern States Power Company`s 130 MWe Black Dog No. 2; TVA`s 160 MWe Shawnee No. 10; Japan`s Electric Power Development Company`s 1,115 t/hr, Takehara Power Station No. 2; Finland`s 360 t/hr, Kainuum Voima Unit; Germany`s Go-Werk Unit at 400 t/hr, Go-Werk Unit at 290 t/hr; France`s 125 MWe E. Huchet Power Station and 250 MWe Provence Power Station. This paper will cover key selection and design features, some operating history, and successful modifications for improved AFBC performance. Design features reviewed are designs developed to control leakage at acceptable levels, cleaning devices and routines to maintain a clean heat transfer surface for satisfactory thermal performance and pressure drop, and maintenance experiences. This summary of experience, based on cooperative efforts with customers, shows availability of the Ljungstrom rotary regenerative heat exchanger on AFBC boilers is similar to that on pulverized coal-fired boilers.

  16. Atmospheric Fluidized Bed Combustion testing of North Dakota lignite

    SciTech Connect

    Goblirsch, G; Vander Molen, R H; Wilson, K; Hajicek, D

    1980-05-01

    The sulfur retention by the inherent alkali, and added limestone sorbent, perform about the same and are reasonably predictable within a range of about +-10% retention by application of alkali to sulfur ratio. Temperature has a substantial effect on the retention of sulfur by the inherent alkali or limestone. The temperature effect is not yet fully understood but it appears to be different for different coals and operational conditions. The emission of SO/sub 2/ from the fluid bed burning the Beulah lignite sample used for these tests can be controlled to meet or better the current emission standards. The injection of limestone to an alkali-to-sulfur molar ratio of 1.5 to 1, should lower the SO/sub 2/ emissions below the current requirement of 0.6 lb SO/sub 2//10/sup 6/ Btu to 0.4 lb SO/sub 2//10/sup 6/ Btu, a safe 33% below the standard. Agglomeration of bed material, and consequent loss of fluidization quality can be a problem when burning high sodium lignite in a silica bed. There appears, however, to be several ways of controlling the problem including the injection of calcium compounds, and careful control of operating conditions. The heat transfer coefficients measured in the CPC and GFETC tests are comparable to data obtained by other researchers, and agree reasonably well with empirical conditions. The NO/sub x/ emissions measured in all of the tests on Beulah lignite are below the current New Source Performance Standard of 0.5 lb NO/sub 2//10/sup 6/ Btu input. Combustion efficiencies for the Beulah lignite are generally quite high when ash recycle is being used. Efficiencies in the range of 98% to 99%+ have been measured in all tests using this fuel.

  17. 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.

  18. 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...

  19. High temperature gas cleaning using honeycomb barrier filter on a coal-fired circulating fluidized bed combustor

    SciTech Connect

    Bishop, B.; Raskin, N.

    1996-12-31

    An efficient particulate hot gas cleaning equipment is a must for the successful commercialization of high efficiency pressurized coal-fired energy conversion systems. Many types of ceramic barrier filter systems are under development during the past decade. Significant progress has been made on the mechanical packaging of ceramic materials at high temperature (up to 900 C) environment. However, there is still considerable difficulty in operating the candle type filters at temperatures close to 900 C. CeraFilter Systems, Inc., and CeraMem Corporation are developing a new type of monolith honeycomb filters for high temperature and high pressure applications. The honeycomb filters have been tested downstream of a coal-fired atmospheric circulating fluidized bed combustor. Coal was fired with limestone as the SO{sub 2} control sorbent. Two test runs were conducted, each at 870 C and at a filtration velocity of 2.2--2.3 cm/s. The testing included both high speed and conventional data acquisition to monitor effects of the cleaning pulses and long term pressure drop characteristics. Dust loadings were measured before and after the filter by the Energy and Environmental Research Center (EERC) of Grand Forks, North Dakota. The dust capture efficiency of the Filter was very high and could easily meet the strict particulate emission level requirements and the allowable dust loading into a gas turbine stream.

  20. Availability of trace elements in solid waste from fluidized bed combustion of coal

    SciTech Connect

    Rope, S.K.; Jornitz, R.S.; Suhre, D.T.

    1987-12-01

    This report presents data on the inorganic constituents (major and trace elements) of coal and solid waste from a coal-fired facility on the Idaho National Engineering Laboratory (INEL) which uses the fluidized bed combustion process. Three factors were used to assess the potential environmental impacts of elements in coal waste: (1) the concentrations relative to those measured previously in surrounding soils of the INEL (the enrichment ratio); (2) the availability of elements from waste relative to soils; and (3) toxicity or essentiality to biota. Considering both enrichment and availability, Al, B, Be, Ca, Cr, Na, Mo, Se, Sr, and Ti are most likely to be affected in the local environment due to fly ash deposition and/or resuspension of FBC waste. Only B, Cr, Mo, and Se are likely to be of concern in terms of toxicity. The high concentrations of Cr and B in FBC waste are expected to be toxic to plants. Concentrations of Se and Mo present in FBC waste have been shown to produce levels in plants which can be toxic to herbivorous animals. 14 refs, 1 fig., 4 tabs.

  1. Behavior of fluorine and chlorine in Spanish coal fired power plants with pulverized coal boilers and fluidized bed boiler.

    PubMed

    López-Vilariño, J M; Fernández-Martínez, G; Turnes-Carou, I; Muinategui-Lorenzo, S; López-Mahía, P; Prada-Rodríguez, D

    2003-06-01

    Behavior and contents of fluorine and chlorine in coal feedstock, combustion wastes (slag and fly ash) and emissions were studied in five conventional coal fired power plants and in a fluidized bed coal power plant. The halide levels found in the used coal were quite low. Mass balances and emission factors were calculated. The volatility of these elements makes the gaseous emission the main target between the residues. The influence of combustion parameters is not clearly established. Several analytical techniques (ion selective electrodes, capillary electrophoresis and ion chromatography) are employed to determinate the halide concentration in the different samples taken in the power plants studied (coal, slag, fly ash and flue gases). PMID:12868523

  2. Nitric Oxide Reduction over Sewage Sludge and Coal Chars at Conditions Relevant to Staged Fluidized Bed Combustion

    NASA Astrophysics Data System (ADS)

    Salatino, P.; Solimene, R.; Chirone, R.

    The de-NOx potential of coal and of dried and pelletized sewage sludge, a waste-derived fuel candidate for cofiring with coal, is assessed. The experimental procedure is based on operation of a bench scale fluidized bed reactor where NO-doped nitrogen is contacted with batches of the fuel. A second type of experiment has been purposely designed to assess the loss of reactivity of chars toward gasification by NOx as char is heat-treated for pre-set times at temperatures typical of fluidized bed combustion. A simple phenomenological model is developed to shed light on the basic features of the interaction between heterogeneous char-NOx reaction and thermal annealing of the char.

  3. 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

  4. Alkali metals in circulating fluidized bed combustion of biomass and coal: measurements and chemical equilibrium analysis

    SciTech Connect

    Michal P. Glazer; Nafees A. Khan; Wiebren de Jong; Hartmut Spliethoff; Heiko Schuermann; Penelope Monkhouse

    2005-10-01

    Combustion and co-combustion experiments with four kinds of straw, specially selected for their different alkali, Cl, and Si contents, and Colombian black coal were carried out in a circulating fluidized bed (CFB) reactor at Delft University of Technology. The influence of operating conditions and fuel composition on the release of the alkali compounds to the gas phase was investigated. The amount of the total gas-phase sodium and potassium compounds in the flue gases was measured with excimer laser induced fluorescence (ELIF). The results show that the release of gaseous alkali species depends on fuel composition, in particular the K/Cl and K/Si ratios in the fuel. The fuels with high K and Cl values show higher concentrations of the gaseous alkalis. A synergetic effect of the co-combustion with coal was observed, which led to a strong decrease in gaseous alkali concentrations. Together with experiments, chemical equilibrium modeling was performed to help in interpreting the experimental data. The calculations confirmed that the equilibrium is very strongly influenced by the composition of the fuel blend. Moreover, the simulations provided more information on sequestering of alkali species. 22 refs., 5 figs., 4 tabs.

  5. Evaluation of PCDD/Fs emission from fluidized bed incinerators co-firing MSW with coal in China.

    PubMed

    Yan, J H; Chen, T; Li, X D; Zhang, J; Lu, S Y; Ni, M J; Cen, K F

    2006-07-31

    The levels and homologue profile of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from stack gas of three typical fluidized bed incinerators co-firing municipal solid waste (MSW) with Chinese coal were measured. The PCDD/Fs emission was in the range of 0.0054-0.1961 ng I-TEQ/N m(3). Comparison of PCDD/Fs detection results by HRGC/HRMS and HRGC/LRMS suggested that it was feasible to detect fly ash with high PCDD/Fs concentration by HRGC/LRMS. Several factors on PCDD/Fs emission were discussed. The primary reason for the lower PCDD/Fs emission was the inhibition mechanism of relatively high sulfur in feeding coal on PCDD/Fs formation. The emission results also showed that there was no directly correlation between PCDD/Fs levels and CO, O(2) and HCl concentration in flue gas. It was estimated that about 0.1034 g I-TEQ was annually emitted to atmosphere from the tested three MSW incinerators (total daily treatment capacity is 800 tonnes MSW). PMID:16442229

  6. Hydrodynamics of a fluidized bed co-combustor for tobacco waste and coal.

    PubMed

    Zhang, Kai; Yu, Bangting; Chang, Jian; Wu, Guiying; Wang, Tengda; Wen, Dongsheng

    2012-09-01

    The fluidization characteristics of binary mixtures containing tobacco stem (TS) and cation exchange resin (a substitute for coal) were studied in a rectangular bed with the cross-section area of 0.3 × 0.025 m(2). The presence of herbaceous biomass particles and their unique properties such as low density and high aspect ratio resulted in different fluidization behaviors. Three fluidization velocities, i.e. initial, minimum and full fluidization velocities, were observed as the TS mass fraction increased from 7% to 20%, and four hydrodynamic stages were experienced, including the static, segregation, transition and mixing stages, with increasing operational gas velocities. The results suggest that the operational gas velocity should be in the range of 2.0-5.0 times of the minimum fluidization velocity of the binary mixtures, and less than 7% TS mass fraction should be used in an existing bubbling fluidized bed. Higher TS fraction inclusion requires the introduction of central jet gas to improve the mixing effect. PMID:22750501

  7. The O₂-enriched air gasification of coal, plastics and wood in a fluidized bed reactor.

    PubMed

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

    2012-04-01

    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. PMID:21993077

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Char binder for fluidized beds

    DOEpatents

    Borio, Richard W. (Somers, CT); Accortt, Joseph I. (Simsbury, CT)

    1981-01-01

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

  15. A circulating fluidized-bed furnace for combusting anthracite culm and the thermal-contact pyrolysis of coal

    NASA Astrophysics Data System (ADS)

    Rokhman, B. B.

    2007-09-01

    A method for thermal-contact pyrolysis of coal and a furnace design for combusting solid fuel in a circulating fluidized bed are proposed. The geometric, aerodynamic, and physicochemical parameters of the pyrolysis zone situated in the near-wall region of the freeboard space are calculated. It is shown that, if the initial fuel is fed through a part of the annular zones cross-sectional area, the near-wall clusters are destroyed and the concentration of the dispersed phase in the reaction zone increases, both resulting in the thermochemical processing of recirculating coke-ash particles to proceed more rapidly.

  16. Desulfurization and Dechlorination Characteristics of Ca-Base Sorbents in Fluidized Bed for Co-Firing of Waste and Coal

    NASA Astrophysics Data System (ADS)

    Murakami, Takahiro; Liu, Zhihong; Hirata, Tetsuya; Ayabe, Muneo; Huang, Weiguang

    The purpose of this study is to experimentally investigate the desulfurization and dechlorination characteristics of seashell and limestone in two waste-coal co-firing circulating fluidized beds of 50 kg⁄h with different heights (15 m and 6 m). The tested wastes were Japanese RDF and Chinese waste, whilst the employed coals had varied fuel ratios of either 4.5 or 8.8. It was shown that the efficiencies of desulfurization and dechlorination were both higher for seashell than for limestone. At four times and beyond of the stoichiometric ratio of Ca over sulfur and chlorine, i.e. at Ca⁄(S+2Cl) › 4.0, the efficiencies of seashell for desulfurization and dechlorination reached more than 99 % and 80 %, respectively. Under the quoted conditions these efficiencies were only 95 % and 70 % for limestone. Meanwhile, it was found that the calcined seashell had a mean pore size four times bigger than that of calcined limestone, and this was considered to be the cause for the preceding different efficiencies. That is, when the bigger pores existing in calcined seashell allowed the desulfurization and dechlorination reactions to take place throughout the sorbent particles, those reactions were possible only on particles‧ surface for limestone. Furthermore, the work clarified that the dusulfurization and dechlorination efficiencies for the tested different wastes, coals and circulating fluidized beds could be unified according to Ca⁄(S+2Cl) ratio.

  17. Simulation of fluidized bed combustors. I - Combustion efficiency and temperature profile. [for coal-fired gas turbines

    NASA Technical Reports Server (NTRS)

    Horio, M.; Wen, C. Y.

    1976-01-01

    A chemical engineering analysis is made of fluidized-bed combustor (FBC) performance, with FBC models developed to aid estimation of combustion efficiency and axial temperature profiles. The FBC is intended for combustion of pulverized coal and a pressurized FBC version is intended for firing gas turbines by burning coal. Transport phenomena are analyzed at length: circulation, mixing models, drifting, bubble wake lift, heat transfer, division of the FB reactor into idealized mixing cells. Some disadvantages of a coal FBC are pointed out: erosion of immersed heat-transfer tubing, complex feed systems, carryover of unburned coal particles, high particulate emission in off-streams. The low-temperature bed (800-950 C) contains limestone, and flue-gas-entrained SO2 and NOx can be kept within acceptable limits.

  18. Polycyclic aromatic hydrocarbon (PAH) emission from co-firing municipal solid waste (MSW) and coal in a fluidized bed incinerator.

    PubMed

    You, Xiaofang

    2008-01-01

    Polycyclic aromatic hydrocarbons (PAH) emissions from a commercial municipal solid waste incinerator (MSWI) were studied. A MSW-coal mixture and coal only were used as fuel for the fluidized bed incinerator. Seven sampling points were chosen according to the classified four PAH emission pathways: flue gas, residue, ash and water. The mixture of MSW and coal resulted in PAH emission more than that of coal only, and PAH emission increased with increasing MSW mass percentage. Calcium oxide (CaO) or calcium carbonate (CaCO3) was added as a desulfurizer. PAH emission also changed with different desulfurizers because of their different influences on heat balance. The PAH toxic equivalent (TEQ) of all operating conditions was also examined, showing that total daily PAH emission from MSWI can be determined. PMID:17996438

  19. 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.

  20. 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...

  1. EMISSIONS FROM FBC (FLUIDIZED-BED COMBUSTION) BOILERS

    EPA Science Inventory

    The paper provides perspective regarding the environmental acceptability of atmospheric-pressure fluidized-bed boilers, with particular emphasis on the application of this technology as a technique for utilizing coal in the industrial sector. It reviews emission sources within th...

  2. Dual Fluidized Bed Biomass Gasification

    SciTech Connect

    2005-09-30

    The dual fluidized bed reactor is a recirculating system in which one half of the unit operates as a steam pyrolysis device for biomass. The pyrolysis occurs by introducing biomass and steam to a hot fluidized bed of inert material such as coarse sand. Syngas is produced during the pyrolysis and exits the top of the reactor with the steam. A crossover arm, fed by gravity, moves sand and char from the pyrolyzer to the second fluidized bed. This sand bed uses blown air to combust the char. The exit stream from this side of the reactor is carbon dioxide, water and ash. There is a second gravity fed crossover arm to return sand to the pyrolysis side. The recirculating action of the sand and the char is the key to the operation of the dual fluidized bed reactor. The objective of the project was to design and construct a dual fluidized bed prototype reactor from literature information and in discussion with established experts in the field. That would be appropriate in scale and operation to measure the relative performance of the gasification of biomass and low ranked coals to produce a high quality synthesis gas with no dilution from nitrogen or combustion products.

  3. 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.

  4. 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.

  5. 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.

  6. Research on coal-water fuel combustion in a circulating fluidized bed / Badanie spalania zawiesinowych paliw węglowo-wodnych w cyrkulacyjnej warstwie fluidalnej

    NASA Astrophysics Data System (ADS)

    Kijo-Kleczkowska, Agnieszka

    2012-10-01

    In the paper the problem of heavily-watered fuel combustion has been undertaken as the requirements of qualitative coals combusted in power stations have been growing. Coal mines that want to fulfill expectations of power engineers have been forced to extend and modernize the coal enrichment plants. This causes growing quantity of waste materials that arise during the process of wet coal enrichment containing smaller and smaller under-grains. In this situation the idea of combustion of transported waste materials, for example in a hydraulic way to the nearby power stations appears attractive because of a possible elimination of the necessary deep dehydration and drying as well as because of elimination of the finest coal fraction loss arising during discharging of silted water from coal wet cleaning plants. The paper presents experimental research results, analyzing the process of combustion of coal-water suspension depending on the process conditions. Combustion of coal-water suspensions in fluidized beds meets very well the difficult conditions, which should be obtained to use the examined fuel efficiently and ecologically. The suitable construction of the research stand enables recognition of the mechanism of coal-water suspension contact with the inert material, that affects the fluidized bed. The form of this contact determines conditions of heat and mass exchange, which influence the course of a combustion process. The specificity of coal-water fuel combustion in a fluidized bed changes mechanism and kinetics of the process.

  7. A novel three phase fluidized bed process for simultaneous selective flocculation and microbial desulfurization of high sulfur coal

    SciTech Connect

    Fan, Liang-Shih; Bavarian, F.; Attia, Y.A.; Elzeky, M. )

    1990-10-16

    The purpose of this work was to investigate the feasibility of recovery and reclamation of ultrafine coal particles generated during the processing of coal. 10--35% of the total annual tonnage of coal in atypical coal preparation plant is estimated to be lost in forms of ultrafine particles during the mining, shipping, handling, and preparation of the coal. The technical feasibility of the proposed system which consisted of an integrated circuit of selective flocculation followed by microbial desulfurization, has been tested. The results indicate that using selective flocculation/froth flotation circuit, coal recoveryis 85% with 75% pyritic sulfur and 60% ash rejections. The remaining pyritic sulfur in the coal slurry was treated using microbial desulfurization in a draft-tube fluidized bed bioreactor. Using this reactor scheme considerable enhancement of the bioleaching rate was obtained. The results indicate that 90% rejection of pyritic sulfur can be achieved in less than 24 hrs. Note that the previously reported data for the bioleaching rate are from 4 to 12 days for the same amount of pyritic rejection. The results obtained in this work closely reflects the anticipated outcomes which were projected in the original proposal. Consequently, the results of this work implies a significant improvement in bioleaching process and the possibility for the commercialization of the microbial desulfurization process. Our results also indicate further improvement of this process by optimization of reactor sequence and operating conditions.

  8. A novel three phase fluidized bed process for simultaneous selective flocculation and microbial desulfurization of high sulfur coal. Final report

    SciTech Connect

    Fan, Liang-Shih; Bavarian, F.; Attia, Y.A.; Elzeky, M.

    1990-10-16

    The purpose of this work was to investigate the feasibility of recovery and reclamation of ultrafine coal particles generated during the processing of coal. 10--35% of the total annual tonnage of coal in atypical coal preparation plant is estimated to be lost in forms of ultrafine particles during the mining, shipping, handling, and preparation of the coal. The technical feasibility of the proposed system which consisted of an integrated circuit of selective flocculation followed by microbial desulfurization, has been tested. The results indicate that using selective flocculation/froth flotation circuit, coal recoveryis 85% with 75% pyritic sulfur and 60% ash rejections. The remaining pyritic sulfur in the coal slurry was treated using microbial desulfurization in a draft-tube fluidized bed bioreactor. Using this reactor scheme considerable enhancement of the bioleaching rate was obtained. The results indicate that 90% rejection of pyritic sulfur can be achieved in less than 24 hrs. Note that the previously reported data for the bioleaching rate are from 4 to 12 days for the same amount of pyritic rejection. The results obtained in this work closely reflects the anticipated outcomes which were projected in the original proposal. Consequently, the results of this work implies a significant improvement in bioleaching process and the possibility for the commercialization of the microbial desulfurization process. Our results also indicate further improvement of this process by optimization of reactor sequence and operating conditions.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Treatment of chromic tannery wastes using coal ashes from fluidized bed combustion of coal

    SciTech Connect

    Bulewicz, E.M.; Kozak, A.; Kowalski, Z.

    1997-10-01

    A new method of treatment for chromic tannery wastes containing chrome and large amounts organic substances has been investigated. It has been found that the addition of certain types of coal ash from fluid bed combustion technologies, at a suitable temperature and pH, results in effective removal of Cr(III) compounds present in the wastes. The wastes could then be subjected to further processing in conventional biological treatment units. The method is very simple, cheap, and effective and could be used for chromic tannery wastes of different compositions.

  14. 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.

  15. 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.

  16. 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.

  17. Recovery of silica from the gasification of rice husks/coal in the presence of a pilot flame in a modified fluidized bed

    SciTech Connect

    Luan, T.C.; Chou, T.C. )

    1990-09-01

    Combustion of rice husks with and without coal in the presence of a pilot flame in a modified fluidized bed was investigated in the present study. The process was employed to produce raw silica from rice husks by burning off other organic matters. The chemical and physical properties of both the top and the bottom products from the rice husk combustion were found to be strongly influenced by two major factors: the feed rate and the feed composition. It has also been found that coal fed along with rice husks to the combustion process permits easy control of the properties of both solid products and significantly reduces the agglomerating phenomena that occur often in the process. The temperature distribution of the fluidized bed, which reflects the bed operating characteristics, was measured and observed to depend on the frequency of pulsed solid feed.

  18. 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.

  19. The importance of heterogeneous decomposition reactions for the emission levels of NO and N{sub 2}O during fluidized bed combustion of coal

    SciTech Connect

    Boavida, D.; Lobo, L.S.; Gulyurtlu, I.; Cabrita, I.

    1996-12-31

    In the present work, the effects of temperature and type of char on the heterogeneous reduction of both NO and N{sub 2}O on char surfaces were investigated using the TGA technique. The kinetic parameters for the decomposition of both NO and N{sub 2}O on the char surfaces was obtained and correlated with the previous results from the combustion of coals and of the same chars in a laboratorial fluidized bed combustor.

  20. EXPERIMENTAL/ENGINEERING SUPPORT FOR ENVIRONMENTAL PROTECTION AGENCIES FLUIDIZED-BED COMBUSTION (FBC) PROGRAM: FINAL REPORT. VOLUME I. SULFUR OXIDE CONTROL

    EPA Science Inventory

    The report gives results of an investigation of the desulfurization performance and attrition behavior of limestone and dolomite sorbents for atmospheric and pressurized fluidized-bed combustion (FBC) systems used with coal. It gives results of experimental thermogravimetric anal...

  1. 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

  2. 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.

  3. Nitrogen evolution during the co-combustion of hydrothermally treated municipal solid waste and coal in a bubbling fluidized bed.

    PubMed

    Lu, Liang; Jin, Yuqi; Liu, Hongmei; Ma, Xiaojun; Yoshikawa, Kunio

    2014-01-01

    Nitrogen evolution was studied during the co-combustion of hydrothermally treated municipal solid wastes (HT MSW) and coal in a bubbling fluidized bed (BFB). HT MSW blending ratios as 10%, 20% and 30% (wt.%) were selected and tested at 700, 800, 900 °C. Emissions of NO and N2O from blends were measured and compared with the results of mono-combustion trials. Moreover, concentrations of precursors like NH3 and HCN were also quantified. The results are summarized as follows: NO emissions were predominant in all the cases, which rose with increasing temperature. The blending of HT MSW contributed to the NO reduction. N2O emissions decreased with temperature rising and the blending of HT MSW also presented positive effects. At 30% HT MSW addition, both NO and N2O emissions showed the lowest values (391.85 ppm and 55.33 ppm, respectively at 900 °C). For the precursors, more HCN was detected than NH3 and both played important roles on the gas side nitrogen evolution. PMID:24120458

  4. 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

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

    SciTech Connect

    Leon R. Glicksman; Michael Louge; Hesham F. Younis; Richard Tan; Mathew Hyre; Mark Torpey

    2003-11-24

    This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor an agency thereof, nor any of the their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, A combined-cycle High Performance Power System (HIPPS) capable of overall cycle efficiencies approaching 50% has been proposed and designed by Foster Wheeler Development Corporation (FWDC). A pyrolyzer in the first stage of the HIPPS process converts a coal feedstock into fuel gas and char at an elevated pressure of 1.4 Map. (206 psia) and elevated temperature of 930 C (1700 F). The generated char serves as the feedstock for a Pulverized Coal (PC) boiler operating at atmospheric pressure, and the fuel gas is directly fired in a gas turbine. The hydrodynamic behavior of the pyrolyzer strongly influences the quality of both the fuel gas and the generated char, the energy split between the gas turbine and the steam turbine, and hence the overall efficiency of the system. By utilizing a simplified set of scaling parameters (Glicksman et al.,1993), a 4/7th labscale cold model of the pyrolyzer operating at ambient temperature and pressure was constructed and tested. The scaling parameters matched include solid to gas density ratio, Froude number, length to diameter ratio; dimensionless superficial gas velocity and solid recycle rate, particle sphericity and particle size distribution (PSD).

  6. Fluidized bed calciner apparatus

    DOEpatents

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

    1988-01-01

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

  7. 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.

  8. Biomass fast pyrolysis in a fluidized bed reactor under N2, CO2, CO, CH4 and H2 atmospheres.

    PubMed

    Zhang, Huiyan; Xiao, Rui; Wang, Denghui; He, Guangying; Shao, Shanshan; Zhang, Jubing; Zhong, Zhaoping

    2011-03-01

    Biomass fast pyrolysis is one of the most promising technologies for biomass utilization. In order to increase its economic potential, pyrolysis gas is usually recycled to serve as carrier gas. In this study, biomass fast pyrolysis was carried out in a fluidized bed reactor using various main pyrolysis gas components, namely N(2), CO(2), CO, CH(4) and H(2), as carrier gases. The atmosphere effects on product yields and oil fraction compositions were investigated. Results show that CO atmosphere gave the lowest liquid yield (49.6%) compared to highest 58.7% obtained with CH(4). CO and H(2) atmospheres converted more oxygen into CO(2) and H(2)O, respectively. GC/MS analysis of the liquid products shows that CO and CO(2) atmospheres produced less methoxy-containing compounds and more monofunctional phenols. The higher heating value of the obtained bio-oil under N(2) atmosphere is only 17.8 MJ/kg, while that under CO and H(2) atmospheres increased to 23.7 and 24.4 MJ/kg, respectively. PMID:21232946

  9. 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...

  10. Tube construction for fluidized bed combustor

    DOEpatents

    De Feo, Angelo; Hosek, William

    1984-01-01

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

  11. Fluidized bed combustor and tube construction therefor

    DOEpatents

    De Feo, Angelo; Hosek, William

    1981-01-01

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

  12. 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.

  13. 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.

  14. 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.

  15. A low emission technology -- low cost coal water mixture fired fluidized bed combustion

    SciTech Connect

    Jianhua Yan; Xuguang Jiang; Yong Chi

    1995-12-31

    In this paper, low cost coal water mixture (CWM) FBC technology is described. Low cost CWM may be coal washery sludge or the mixture of water and coal crashed easily. This technology is featured by agglomerate combustion of low cost MM. Experimental results in 0.5MW FBC test rig are reported. lie effects of bed temperate excess air, staged combustion on combustion and emission performance has been studied. The comparison combustion tests by using dry coal and CWM we made ha 0.5MW FBC test rig. Also coal washery sludge of different origins are also tested in the test rig. Based on the test rig comments a demonstration AFBC boiler with capacity of 35 T/H steam for utility application (6 MW) is designed. The design features will be presented in this paper Both the operation experience of test rig and demonstration unit show the developed low cost CWM FBC technology is of high combustion efficiency and low emission. This technology is being commercialized and applied in China in top priority by Chinese government.

  16. Alternative fuel firing in an atmospheric fluidized-bed combustion boiler. Final report. [Also with other waste fuels

    SciTech Connect

    Miraglio, A.; Tegen, P.

    1985-06-01

    In 1981, Northern States Power Company converted its 15 MW French Island Unit No. 2 from a stoker-fired boiler to an atomspheric fluidized bed combustor designed to burn wood waste. A joint project between Northern States Power and the Electric Power Research Institute was subsequently established to determine the impact on operations, performance, and emissions of cofiring a variety of low-grade waste fuels with wood waste in this unit. Alternate waste fuels fired were shredded rubber tires, shredded railroad ties, refuse derived fuel, Minnesota peat, and sewage sludge. Each fuel was cofired with wood waste under steady boiler conditions for 50 to 100 hours. Results from the initial alternate fuel tests showed incomplete combustion of the fluidized bed combustor. To correct this problem the overfire air system was modified to improve mixing in the furnace volume above the fluidized bed. After the overfire air system was modified, the fluidized bed combustor proved able to burn all waste fuels effectively, except rubber tires which were not re-tested. Fuel handling problems were encountered with refuse derived fuel, peat and sewage sludge, but did not prevent their successful firing. Fluidized bed contamination was experienced with steel wire from rubber tires and stones and steel pieces from railroad ties. Also, the particulate scrubber was overloaded when firing high ash fuels such as rubber tires and peat. 2 refs., 21 figs., 32 tabs.

  17. 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

  18. Mercury emissions during cofiring of sub-bituminous coal and biomass (chicken waste, wood, coffee residue, and tobacco stalk) in a laboratory-scale fluidized bed combustor.

    PubMed

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

    2008-12-15

    Four types of biomass (chicken waste, wood pellets, coffee residue, and tobacco stalks) were cofired at 30 wt % with a U.S. sub-bituminous coal (Powder River Basin Coal) in a laboratory-scale fluidized bed combustor. A cyclone, followed by a quartz filter, was used for fly ash removal during tests. The temperatures of the cyclone and filter were controlled at 250 and 150 degrees C, respectively. Mercury speciation and emissions during cofiring were investigated using a semicontinuous mercury monitor, which was certified using ASTM standard Ontario Hydra Method. Test results indicated mercury emissions were strongly correlative to the gaseous chlorine concentrations, but not necessarily correlative to the chlorine contents in cofiring fuels. Mercury emissions could be reduced by 35% during firing of sub-bituminous coal using only a quartz filter. Cofiring high-chlorine fuel, such as chicken waste (Cl = 22340 wppm), could largely reduce mercury emissions by over 80%. When low-chlorine biomass, such as wood pellets (Cl = 132 wppm) and coffee residue (Cl = 134 wppm), is cofired, mercury emissions could only be reduced by about 50%. Cofiring tobacco stalks with higher chlorine content (Cl = 4237 wppm) did not significantly reduce mercury emissions. This was also true when limestone was added while cofiring coal and chicken waste because the gaseous chlorine was reduced in the freeboard of the fluidized bed combustor, where the temperature was generally below 650 degrees C without addition of the secondary air. Gaseous speciated mercury in flue gas after a quartz filter indicated the occurrence of about 50% of total gaseous mercury to be the elemental mercury for cofiring chicken waste, but occurrence of above 90% of the elemental mercury for all other cases. Both the higher content of alkali metal oxides or alkali earth metal oxides in tested biomass and the occurrence of temperatures lower than 650 degrees C in the upper part of the fluidized bed combustor seemed to be responsible for the reduction of gaseous chlorine and, consequently, limited mercury emissions reduction during cofiring. This study identified the important impacts of temperature profile and oxides of alkali metal (alkali earth metal) on mercury emissions during cofiring in the fluidized bed combustor. PMID:19174919

  19. 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.

  20. Granular filtration in a fluidized bed

    SciTech Connect

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

    1995-12-31

    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 stream. 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 in-flowing 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. Batch mode filtration performance of the filter was first reported at the Ninth Annual Coal-Fueled Heat Engines, Advanced Pressurized Fluidized-Bed Combustion, and Gas Stream Cleanup Systems Contractors Review Meeting.

  1. 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.

  2. 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 ...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

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

    SciTech Connect

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

    1980-12-01

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

  8. 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.

  9. 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)

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Manual for applying fluidized bed combustion residue to agricultural lands

    SciTech Connect

    Not Available

    1988-08-01

    Atmospheric fluidized bed combustion (AFBC) is a process that reduces sulfur emissions from coal-fired electric-generating plants. The residue from this process is a mixture of alkaline oxides, calcium sulfate, and coal ash constituent. Since 1976, USDA/ARS has investigated the potential agriculture use of this residue. The investigations comprised an extensive series of laboratory, greenhouse, field plot, and animal feeding experiments. The best and safest use of AFBC residue in agriculture was as a substitute for agricultural lime. This report contains guidelines for applying AFBC residue to agricultural lands. 2 figs., 27 refs., 2 tabs.

  15. 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.

  16. Apparatus for controlling fluidized beds

    DOEpatents

    Rehmat, Amirali G.; Patel, Jitendra G.

    1987-05-12

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

  17. 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.

  18. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system. Fourth quarter progress report, July 1-September 30, 1982

    SciTech Connect

    1983-02-17

    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. Technical progress summaries and reports are presented for the following tasks: (1) process development unit (PDU) test operations and results (gasifier test TP-033-1 and maintenance and modifications); (2) process analysis (environmental characterization results, coal gas combustion results, and fines elutriation and consumption results); (3) cold flow scaleup (modifications and maintenance, operations, and data analysis); (4) process and component engineering and design (hot fines recycle modifications, and hot recycled fines); (5) laboratory support studies (gas-solids flow modeling and coal/ash behavior). 23 figures, 23 tables.

  19. Pulsed atmospheric fluidized bed combustion. Technical progress report, April--June 1995

    SciTech Connect

    1995-07-31

    Design activities for this report period included: (1) Mechanical. Stress analysis calculations were performed on the steam/water pressure piping. Pipe support design and drawings were completed by Duke Fluor Daniel. The fluid bed distributor bubble cap design was revisited and changes made for ease of maintenance. (2) Electrical and Instrumentation. Control and instrumentation scheme proposed earlier, was based on independent single loop controllers. After careful review, it is decided to go for state of art distributed control system (DCS) which uses programmable logic controllers (PLC). In addition, coal/limestone pickup hopper fabrication was completed during this period and shipped to the site. The coal/limestone floating caps have been made at MTCI and ready for shipping. All major equipment installation was completed. The pulse combustor steam/water jacket and air plenum were installed. Construction of control room building was just completed.

  20. Pulsed atmospheric fluidized bed combustion. Quarterly report, July 1--September 30, 1995

    SciTech Connect

    1995-12-31

    The report summarizes progress in design, fabrication, and construction activities. Progress on the fluid bed combustor, piping, fuel feeding system, ash system, and the control and instrumentation design is described. The report lists the construction activities completed during this quarter which included bed tubes installation, fan inlet flow measuring duct, bag filter, silencers for roots blowers, electric power cabling connections, light distributor panel and transformer installation inside the control panel, steam/water recirculation piping, fine coal receiving vent filter, and partial painting of ash silo and boiler.

  1. 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.

  2. Corrosion data for uncooled alloys in the bed of an atmospheric fluidized-bed boiler

    SciTech Connect

    Not Available

    1981-08-01

    The major conclusions drawn from the results of this particular corrosion test were that: above the coal feed ports, Alloys 304, 310, and 800 were the most resistant. However, Alloys 800 and 310 were subject to catastrophic attack at points of contact with Alloy 600. All three alloys formed subscale sulfides; in oxidizing zones away from the coal feed ports, only Inconel 671 suffered especially rapid attack. The lower chromium (16 to 19%) alloy specimens - C276, 347, 304, 18SR, and 430 - suffered some internal sulfidation, and both the 304 and 310 rods beneath the specimen probe suffered rapid penetration; on the basis of this test alone, alloys containing more than 40% nickel should not be considered for use within the bed of FBC units. Alloys containing 20 to 40% nickel should be evaluated very carefully, giving consideration to possible occurrence of rapid attack under low oxygen conditions and in crevice areas; austenitic stainless steels appear to be promising candidates for uncooled, in-bed applications. Extended testing (2,000 to 10,000 hour) of these alloys is needed.

  3. Sewage sludge combustion in the fluidized bed: Comparison of stationary and circulating fluidized bed techniques

    SciTech Connect

    Werther, J.; Ogada, T.; Phillippek, C.

    1995-12-31

    This paper presents results of investigations concerning CO and NO{sub x} emissions during the incineration of different digested sewage sludge samples in stationary and circulating fluidized bed combustors. The stationary fluidized bed combustion rig is 9 m high while the circulating fluidized bed combustor has a total height of 15 m. Both combustors are 100 mm in diameter. The digested sewage sludges originated from different municipal wastewater treatment plants. They were fed into the combustors as either predried granulates with 6--13 wt.-% water contents or as a slurry with water contents between 70 and 80 wt.-%. For comparison, bituminous and brown coals were also investigated. Measurements from both combustors have shown that predried sludges yield much higher NO{sub x} emission levels than coals under equivalent combustion conditions. Combustion of wet sludges resulted in extremely low NO{sub x} emissions compared to predried sludges. Staged combustion of predried sludge granulates proved to be effective for lowering the emissions of NO{sub x}. Experiments with wet sludges showed no significant difference in CO and NO{sub x} emissions between stationary and circulating fluidized bed combustors although with predried sludges and coals, clearly lower NO{sub x} emissions were measured from the circulating fluidized bed test unit.

  4. 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.

  5. Scaling of pressurized fluidized beds

    SciTech Connect

    Guralnik, S.; Glicksman, L.R.

    1994-10-01

    The project has two primary objectives. The first is to verify a set of hydrodynamic scaling relationships for commercial pressurized fluidized bed combustors (PFBC). The second objective is to investigate solids mixing in pressurized bubbling fluidized beds. American Electric Power`s (AEP) Tidd combined-cycle demonstration plant will provide time-varying pressure drop data to serve as the basis for the scaling verification. The verification will involve demonstrating that a properly scaled cold model and the Tidd PFBC exhibit hydrodynamically similar behavior. An important issue in PFBC design is the spacing of fuel feed ports. The feed spacing is dictated by the fuel distribution and the mixing characteristics within the bed. After completing the scaling verification, the cold model will be used to study the characteristics of PFBCs. A thermal tracer technique will be utilized to study mixing both near the fuel feed region and in the far field. The results allow the coal feed and distributor to be designed for optimal heating.

  6. 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.

  7. 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.

  8. 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%.

  9. Multicycle study on chemical-looping combustion of simulated coal gas with a CaSO{sub 4} oxygen carrier in a fluidized bed reactor

    SciTech Connect

    Qilei Song; Rui Xiao; Zhongyi Deng; Wenguang Zheng; Laihong Shen; Jun Xiao

    2008-11-15

    The cyclic test of a CaSO{sub 4}-based oxygen carrier (natural anhydrite) in alternating reducing simulated coal gas and oxidizing conditions was performed at 950{degree}C in a fluidized bed reactor at atmospheric pressure. A high concentration of CO{sub 2} was obtained in the reduction. The H{sub 2} and CO conversions and CO{sub 2} yield increased initially and final decreased significantly. The release of SO{sub 2} and H{sub 2}S during the cyclic test was found to be responsible for the decrease of reactivity of a CaSO{sub 4} oxygen carrier. The oxygen carrier conversion after the reduction reaction decreased gradually in the cyclic test. Through the comparison of mass-based reaction rates as a function of mass conversion at typical cycles, it was also evident that the reactivity of a CaSO{sub 4} oxygen carrier increased for the initial cycles but finally decreased after around 15 cycles. X-ray diffraction analysis revealed that the presence and intensity of the reduction sulfur species was in accordance with the results of gas conversion. The content of CaO was higher than expected, suggesting the formation of SO{sub 2} and H{sub 2}S during the cycles. Surface morphology analysis demonstrates that the natural anhydrite particle surface varied from impervious to porous after the cyclic test. It was also observed that the small grains on the surface of the oxygen carrier sintered in the cyclic tests. Energy-dispersive spectrum analysis also demonstrated the decrease of oxygen intensity after reduction, and CaO became the main component after the 20th oxidation. Pore structure analysis suggested that the particles agglomerated or sintered in the cyclic tests. The possible method for sulfur mitigation is proposed. Finally, some basic consideration on the design criteria of a CLC system for solid fuels using a CaSO{sub 4} oxygen carrier is discussed by the references and provides direction for future work. 49 refs., 10 figs., 5 tabs.

  10. 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.

  11. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume 1. Model evolution and development

    SciTech Connect

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

    1980-10-01

    The Energy Laboratory of the Massachusetts Institute of Technology (M.I.T.), under Department of Energy (DOE) sponsorship, has been engaged in the development of a comprehensive mechanistic model of Fluidized Bed Combustors (FBC). The primary aims of this modeling effort are the generation and to the extent possible, validation of an analytical framework for the design and scale-up of fluidized bed combustors. In parallel with this modeling effort, M.I.T. also embarked upon the development of an FBC-Data Base Management System (FBC-DBMS) aimed at facilitating the coordination, interpretation and utilization of the experimental data that are or will become available from diverse sources, as well as in the identification of areas of large uncertainty or having a paucity of experimental results. The synergistic operation of the FBC-Model and FBC-Data Base promises to offer a powerful tool for the design and optimization of FBC's and represents the ultimate goal of the M.I.T. effort. The modeling effort was initially focused upon evaluation and application of state-of-the-art models. The initial system model was divided into five basic components: fluid dynamics, combustion, sulfur capture, heat transfer and emissions. Due to the technical complexity of modeling FBC operation and the initial primitive nature of models for these components, it was deemed necessary to be able to incorporate evolutionary improvements in understanding and correlating FBC phenomena: the M.I.T. system model is, therefore, modular in nature, i.e., each sub-model can be replaced by an updated or equivalent sub-model without necessitating reprogramming of the entire system model.

  12. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.; Marasco, Joseph A.

    1995-01-01

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

  13. 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.

  14. 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.

  15. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.; Marasco, Joseph A.

    1996-01-01

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

  16. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.

    1993-01-01

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

  17. 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.

  18. Fluidized-bed-fired industrial boilers

    SciTech Connect

    Leon, A.M.; McCoy, D.E.

    1981-01-01

    E. Keeler Company and Dorr-Oliver, Inc. have joined to design, market and manufacture atmospheric fluidized-bed-fired boilers. The first contract, called Shamokin, was a 23,400 lb/hr unit fired with anthracite culm having a heating value of 4000 Btu/lb and 67% ash. The Department of Energy sponsored this plant as a demonstration project. Boiler erection is nearly complete and start-up is scheduled for mid-1981. In conjunction with the Shamokin project, a line of fluidized-bed-fired boilers to 250,000 lb/hr has been developed for conventional solid fuels. The development of fluidized-bed-fired, industrial boilers is in its very early stages. At this point, it is not possible for any manufacturer to claim extensive operating experience with any particular design under the varied applications normal to industrial watertube boilers. Many different designs and approaches will develop over the next few years and until there has been some operating experience, it is not possible to evaluate just what share of the future industrial boiler market will utilize fluidized-bed firing.

  19. Fast fluidized bed steam generator

    DOEpatents

    Bryers, Richard W.; Taylor, Thomas E.

    1980-01-01

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

  20. Predictive models for circulating fluidized bed combustors

    SciTech Connect

    Gidaspow, D.

    1989-11-01

    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. The purpose of these models is to help American industry, such as Combustion Engineering, design and scale-up CFB combustors that are capable of burning US Eastern high sulfur coals with low SO{sub x} and NO{sub x} emissions. In this report, presented as a technical paper, solids distributions and velocities were computed for a PYROFLOW circulating fluidized bed system. To illustrate the capability of the computer code an example of coal-pyrite separation is included, which was done earlier for a State of Illinois project. 24 refs., 20 figs., 2 tabs.

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

    PubMed

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

    2003-08-01

    During incineration, secondary pollutants such as acid gases, organic compounds, heavy metals and particulates are generated. Among these pollutants, the acid gases, including sulfur oxides (SO(x)) and hydrogen chloride (HCl), can cause corrosion of the incinerator piping and can generate acid rain after being emitted to the atmosphere. To address this problem, the present study used a novel combination of air pollution control devices (APCDs), composed of a fluidized bed adsorber integrated with a fabric filter. The major objective of the work is to demonstrate the performance of a fluidized bed adsorber for removal of acid gases from flue gas of an incinerator. The adsorbents added in the fluidized bed adsorber were mainly granular activated carbon (AC; with or without chemical treatment) and with calcium oxide used as an additive. The advantages of a fluidized bed reactor for high mass transfer and high gas-solid contact can enhance the removal of acid gases when using a dry method. On the other hand, because the fluidized bed can filter particles, fine particles prior to and after passing through the fluidized bed adsorber were investigated. The competing adsorption on activated carbon between different characteristics of pollutants was also given preliminary discussion. The results indicate that the removal efficiencies of the investigated acid gases, SO(2) and HCl, are higher than 94 and 87%, respectively. Thus, a fluidized bed adsorber integrated with a fabric filter has the potential to replace conventional APCDs, even when there are other pollutants at the same time. PMID:12935758

  2. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system. Third quarter progress report FY-1984, April 1-June 30, 1984

    SciTech Connect

    Not Available

    1986-01-31

    The overall objective of the KRW coal gasification program is to demonstrate the viability of the KRW 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) modifications to the PDU; (3) cold flow scaleup facility; (4) advanced process design and analysis; and (5) laboratory support studies. For laboratory support studies, coal and/or char fines from Wyoming Sub C, Western Kentucky, Republic of South Africa (RSA), and Pittsburgh seam coals processed in the PDU were characterized for reactivity on a thermogravimetric analyzer. The average relative reactivity of the fines (-120 x +140 mesh) was found to be nearly the same as that for larger size distribution (18 x 60 mesh, -1.0 + 0.25 mm). This is consistent with the observations of studies reported in literature on carbon gasification reactions.

  3. Emissions During Co-Firing of RDF-5 with Coal in a 22 t/h Steam Bubbling Fluidized Bed Boiler

    NASA Astrophysics Data System (ADS)

    Wan, Hou-Peng; Chen, Jia-Yuan; Juch, Ching-I.; Chang, Ying-Hsi; Lee, Hom-Ti

    The co-firing of biomass and fossil fuel in the same power plant is one of the most important issues when promoting the utilization of renewable energy in the world. Recently, the co-firing of coal together with biomass fuel, such as "densified refuse derived fuel" (d-RDF or RDF-5) or RPF (refuse paper & plastic fuel) from waste, has been considered as an environmentally sound and economical approach to both waste remediation and energy production in the world. Because of itscomplex characteristics when compared to fossil fuel, potential problems, such as combustion system stability, the corrosion of heat transfer tubes, the qualities of the ash, and the emissionof pollutants, are major concerns when co-firing the biomass fuel with fossil fuel in a traditional boiler. In this study, co-firing of coal with RDF-5 was conducted in a 22t/h bubbling fluidized bed (BFB) steam boiler to investigate the feasibility of utilizing RDF-5 as a sustainable fuels in a commercial coal-fired steam BFB boiler. The properties of the fly ash, bottom ash, and the emission of pollutants are analyzed and discussed in this study.

  4. Evaluation of PCDD/Fs and metals emission from a circulating fluidized bed incinerator co-combusting sewage sludge with coal.

    PubMed

    Zhang, Gang; Hai, Jing; Cheng, Jiang; Cai, Zhiqi; Ren, Mingzhong; Zhang, Sukun; Zhang, Jieru

    2013-01-01

    The emission characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and heavy metals were evaluated during co-combustion of sewage sludge with coal from a circulating fluidized bed incinerator. The stack gas, slag and fly ash samples were sampled and analyzed. The gas-cleaning system consisted of electrostatic precipitators and a semi-dry scrubber. Results showed that the stack gas and fly ash exhibited mean dioxin levels of 9.4 pg I-TEQ/Nm3 and 11.65 pg I-TEQ/g, respectively, and showed great similarities in congener profiles. By contrast, the slag presented a mean dioxin level of 0.15 pg I-TEQ/g and a remarkable difference in congener profiles compared with those of the stack gas and fly ash. Co-combusting sewage sludge with coal was able to reduce PCDD/Fs emissions significantly in comparison with sewage sludge mono-combustion. The leaching levels of Hg, Pb, Cd, Ni, Cr, Cu, and As in the fly ash and slag were much lower than the limits of the environmental protection standard in China. These suggest that the co-combustion of sewage sludge and coal is an advisable treatment method from an environmental perspective. PMID:23586319

  5. Feasibility study on solidification of municipal solid waste incinerator fly ash with circulating fluidized bed combustion coal fly ash.

    PubMed

    Liu, Wenshi; Hou, Haobo; Zhang, Chuhao; Zhang, Dajie

    2009-05-01

    The objective of this study was to assess the feasibility of solidification of municipal solid waste incinerator (MSWI) fly ash with circulation fluidized bed combustion (CFBC) fly ash, which is unsuitable as a cement replacement due to its high amounts of carbon, lime and anhydrite. The solidification process was conducted on samples prepared from MSWI fly ash, binders (cement clinkers and CFBC fly ash were mixed at two replacement ratios) and water (water/solid weight ratio = 0.4), among which the MSWI fly ash replaced each binder at the ratio of 0, 20, 40, 60 and 80% by dry weight. The samples were subjected to compressive strength tests and Toxicity Characteristic Leaching Procedure and the results showed that all solidified MSWI fly ash can meet the landfill standard imposed by US EPA after 28 days of curing. Micro-analysis (X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectrophotometry) revealed that the main hydrate products were C-S-H gel and ettringite, which have a positive effect on heavy metals retention. Therefore, this method provides a possibility to achieve a cheap and effective solution for MSWI fly ash management and use for CFBC fly ash. PMID:19423575

  6. Use of a tapered fluidized bed as a continuous bioreactor.

    PubMed

    Scott, C D; Hancher, C W

    1976-10-01

    Reactor systems based on tapered fluidized beds are being developed for aqueous bioprocesses in which adhering microorganisms or immobilized active biological fractions are used. The use of a fluidized bed prevents biomass buildup, accommodates particulates in the feed stream, is compatible with gas sparging, and allows easy removal or addition of the active materials. The tapered reactor tends to stabilize the fluidized bed, thus allowing a much wider range of operating conditions. Preliminary experimental results and an empirical mathematical model of the tapered bed indicate that bed stability is associated with a decreasing velocity and void-fraction profile up the bed and the pressure drop across the bed decreases with increasing flow rates. The tapered fluidized bed bioreactor is being evaluated for use in the enzymatic production of hydrogen, microbiological denitrification, and microbiological degradation of coal conversion aqueous waste streams. The enzyme catalyzed conversion of lactose to glucose and galactose was used in the evaluation of the reactor concept. PMID:963280

  7. 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.

  8. 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.

  9. 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.

  10. Modeling of fluidized-bed combustion of coal: Phase II, final reports. Volume II. Detailed description of the model

    SciTech Connect

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

    1980-10-01

    This document is the second of a seven volume series of our Phase II Final Report. This volume deals with detailed descriptions of the structure of each program member (subroutines and functions), the interrelation between the members of a submodel, and the interrelation between the various submodels as such. The systems model for fluidized bed combustors (FBC-II) consists of a systematic combination of the following interrelated areas: fluid mechanics and bubble growth, char combustion and associated kinetics for particle burnout, sulfur capture, NO/sub x/ formation and reduction, freeboard reactions, and heat transfer. Program outline is shown in Figure 1.1. Input variables (supplied by the user are inspected to check that they lie inside the allowed range of values and are input to the various routines as needed. The necessary physical and fluid mechanical properties are calculated and utilized in estimating char combustion and sulfur capture in the bed and the freeboard. NO/sub x/ and CO emissions are estimated by taking into account all relevant chemical reactions. A material and energy balance is made over the bed. Figure 1.1 shows a block diagram of the systems program. In this diagram, the overall structure of the FBC program is illustrated in terms of the various submodels that together constitute the systems program. A more detailed outline of the systems program is shown in Figure 1.2. In this figure, all important subroutine members of the FBC program are shown, and their linkage to each other, as well as to the main program is indicated. A description of the exact sequence in which these various routines are called at time of program execution is provided in Chapter 8 under the executive routine MAIN.

  11. Engineer, design, construct, test and evaluate a pressurized fluidized bed pilot plant using high sulfur coal for production of electric power. Phase I. Preliminary engineering

    SciTech Connect

    Not Available

    1980-04-01

    The main objective of this program is to evaluate the commercial potential of a power generating concept that includes the pressurized, fluidized bed combustion of coal in conjunction with a combined gas-steam turbine cycle. The capability to burn high-sulfur coal in an environmentally acceptable manner is a requirement. The program involves conceptual commercial design, supporting experimental work, and the design, construction and operation of a PFB pilot plant which can be used to evaluate the commercial concept. The SGT/PFB Technology Unit was designed, procured, erected at the Curtiss-Wright Plant in Wood-Ridge, New Jersey, and placed in operation in 1977. Parametric performance evaluation tests were conducted and completed in July 1978. The secondary gas cleanup system was then modified to include three inertial-type units in series. In mid-1979 the test program was again initiated with the following objectives: Continued evaluation of candidate heat exchanger tube materials to determine the rate data for tube life prediction; evaluation of candidate turbine blade and vane materials and coatings to determine rate data for life prediction; evaluation of the modified hot gas cleanup system; conduct particulate grab sample tests throughout the test to determine grain loading and particle size distribution; and gas turbine operation for 1000 h while burning high sulfur coal in the PFB combustor. Total operating time to date is 3378 hours which includes 2681 hours burning coal and 1205 hours total turbine engine operation. Significant performance and operational milestones have been accomplished and are reported. (LCL)

  12. Emissions of SO2, NO and N2O in a circulating fluidized bed combustor during co-firing coal and biomass.

    PubMed

    Xie, Jian-jun; Yang, Xue-min; Zhang, Lei; Ding, Tong-li; Song, Wen-li; Lin, Wei-gang

    2007-01-01

    This paper presents the experimental investigations of the emissions of SO2, NO and N20 in a bench scale circulating fluidized bed combustor for coal combustion and co-firing coal and biomass. The thermal capacity of the combustor is 30 kW. The setup is electrically heated during startup. The influence of the excess air, the degree of the air staging, the biomass share and the feeding position of the fuels on the emissions of SO2, NO and N2O were studied. The results showed that an increase in the biomass shares resulted in an increase of the CO concentration in the flue gas, probably due to the high volatile content of the biomass. In co-firing, the emission of SO2 increased with increasing biomass share slightly, however, non-linear increase relationship between SO2 emission and fuel sulfur content was observed. Air staging significantly decreased the NO emission without raising the SO2 level. Although the change of the fuel feeding position from riser to downer resulted in a decrease in the NO emission level, no obvious change was observed for the SO2 level. Taking the coal feeding position R as a reference, the relative NO emission could significantly decrease during co-firing coal and biomass when feeding fuel at position D and keeping the first stage stoichiometry greater than 0.95. The possible mechanisms of the sulfur and nitrogen chemistry at these conditions were discussed and the ways of simultaneous reduction of SO2, NO and N20 were proposed. PMID:17913163

  13. Particle pressures in fluidized beds

    SciTech Connect

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

    1992-01-01

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

  14. Voidage and pressure profile characteristics of sand-iron ore-coal-FCC single-particle systems in the riser of a pilot plant circulating fluidized bed

    SciTech Connect

    Das, M.; Meikap, B.C.; Saha, R.K.

    2008-06-15

    Hydrodynamic behaviors of single system of particles were investigated in a circulating fluidized bed (CFB) unit. Particles belonging to Geldart groups A and B like sand of various sizes (90, 300, 417, 522, 599, and 622 mu m), FCC catalyst (120 mu m), iron ore (166 and 140 {mu} m), and coal (335 and 168 {mu} m) were used to study the hydrodynamic characteristics. Superficial air velocity used in the present study ranged between 2.01 and 4.681 m/s and corresponding mass fluxes were 12.5-50 kg/(m{sup 2} s). A CFB needs the creation of some special hydrodynamic conditions, namely a certain combination of superficial gas velocity, solids circulation rate, particle diameter, density of particle, etc. which can give rise to a state wherein the solid particles are subjected to an upward velocity greater than the terminal or free fall velocity of the majority of the individual particles. The hydrodynamics of the bed was investigated in depth and theoretical analysis is presented to support the findings. Based on gas-solid momentum balance in the riser, a distinction between apparent and real voidage has been made. The effects of acceleration and friction on the real voidage have been estimated. Results indicated a 0.995 voidage for higher superficial gas velocity of 4.681. m/s.

  15. 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.

  16. PCDD/F concentrations of agricultural soil in the vicinity of fluidized bed incinerators of co-firing MSW with coal in Hangzhou, China.

    PubMed

    Yan, J H; Xu, M X; Lu, S Y; Li, X D; Chen, T; Ni, M J; Dai, H F; Cen, K F

    2008-03-01

    The concentrations of 17PCDD/F congeners as well as tetra- to octa-homologues were determined in 33 soil samples collected within a radius of 7 km from a municipal solid waste (MSW) incineration plant that is equipped with three fluidized bed incinerators (FBIs) of co-firing MSW with coal in Hangzhou, China. The total PCDD/F concentrations ranged from 0.39 to 5.04 pg I-TEQ g(-1) (54-285 pg g(-1)), with an average and a median value of 1.22 and 0.84 pg I-TEQ g(-1) (105 and 86 pg g(-1)), respectively. A systematic decrease of PCDD/F levels was observed with the increasing distances and with the decreasing downwind frequencies from the plant. The comparisons of homologue and congener patterns and multivariate analysis of soil and flue gas samples strongly indicated that most of the soil samples were influenced by the FBIs. Apart from the incineration plant, historical PCDD/F emissions of hazardous waste incinerator (HWI) and motor vehicles as well as the application of 1,3,5-trichloro-2-(4-nitrophenoxy) benzene (CNP) seemed to play an important role in soil samples adjacent to these potential sources. PMID:17640802

  17. Pressurized fluidized bed reactor

    DOEpatents

    Isaksson, Juhani

    1996-01-01

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

  18. 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.

  19. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system. Quarterly progress report, April 1-June 30, 1982

    SciTech Connect

    1982-10-21

    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 and component engineering and design; and (5) laboratory support studies. Some of the highlights for this period are: TP-032-1, a single stage, oxygen-steam blown gasifier test was conducted in three operational phases from March 30, 1982 through May 2, 1982; TP-032-2 was conducted in two operational phases from May 20, 1982 through May 27, 1982; TP-032-1 and TP-032-2 successfully served as shakedown and demonstrations of the full cyclone cold wall; no visible deposits were found on the cold wall after processing highly fouling coals; samples of product gas produced during TP-032-1, were passed through four different scrubbing solutions and analyzed for 78 EPA primary organic pollutants, all of which were found to be below detection limits; TP-M004, a CO/sub 2/ tracer gas test, was initiated and completed; data analysis of test TP-M002-2 was completed and conclusions are summarized in this report; design, procurement and fabrication of the solids injection device were completed; laboratory studies involved gas-solids flow modeling and coal/ash behavior. 2 references, 11 figures, 39 tables.

  20. 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)

  1. Filling abandoned mines with fluidized bed combustion ash grout

    SciTech Connect

    Gray, D.D.; Reddy, T.P.; Black, D.C.; Ziemkiewicz, P.F.

    1998-10-01

    The hydraulic backfilling of abandoned room and pillar coal mines with ash-based grout holds promise as an environmentally beneficial method of ash disposal, capable of preventing acid mine drainage and subsidence. For this scheme to be economically viable, the grout must be sufficiently flowable so that mines can be filled from a small number of boreholes. This paper describes the development and testing of a water-ash-bentonite grout using ash from a coal and gob burning atmospheric pressure fluidized bed combustor. Bentonite was needed to prevent settling which would limit the ability of the grout to spread. Laboratory techniques were devised to measure the rheological parameters of the grout. A static model was developed to predict the maximum distance of spread due to gravity. A field injection of 765 m{sup 3} of grout into an inactive mine panel showed that the grout flows well enough to make hydraulic backfilling feasible.

  2. Effect of temperature on reduction of CaSO{sub 4} oxygen carrier in chemical-looping combustion of simulated coal gas in a fluidized bed reactor

    SciTech Connect

    Song, Q.L.; Xiao, R.; Deng, Z.Y.; Shen, L.H.; Xiao, J.; Zhang, M.Y.

    2008-12-15

    Chemical-looping combustion (CLC) is a promising combustion technology for gaseous and solid fuel with efficient use of energy and inherent separation of CO{sub 2}. The concept of a coal-fueled CLC system using, calcium sulfate (CaSO{sub 4}) as oxygen carrier is proposed in this study. Reduction tests of CaSO{sub 4} oxygen carrier with simulated coal gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890-950{degree}C. A high concentration of CO{sub 2} was obtained at the initial reduction period. CaSO{sub 4} oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. The sulfur release during the reduction of CaSO{sub 4} as oxygen carrier was also observed and analyzed. H{sub 2} and CO{sub 2} conversions were greatly influenced by reduction temperature. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates and result in high conversion of oxygen carrier. An XRD patterns study indicated that CaS was the dominant product of reduction and the variation of relative intensity with temperature is in agreement with the solid conversion. ESEM analysis indicated that the surface structure of oxygen carrier particles changed significantly from impervious to porous after reduction. EDS analysis also demonstrated the transfer of oxygen from the oxygen carrier to the fuel gas and a certain amount of sulfur loss and CaO formation on the surface at higher temperatures. The reduction kinetics of CaSO{sub 4} oxygen carrier was explored with the shrinking unreacted-core model. The apparent kinetic parameters were obtained, and the kinetic equation well predicted the experimental data. Finally, some basic considerations on the use of CaSO{sub 4} oxygen carrier in a CLC system for solid fuels were discussed.

  3. 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.

  4. 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.

  5. Characterization of solid fuels at pressurized fluidized bed gasification conditions

    SciTech Connect

    Zevenhoven, R.; Hupa, M.

    1998-07-01

    The gasification of co-gasification of solid fuel (coal, peat, wood) in air-blown fluidized bed gasifiers is receiving continued attention as an alternative to entrained flow gasifiers which in general are oxygen-blown. Fluidized bed gasification of wood and wood-waste at elevated pressures, and the so-called air-blown gasification cycle are examples of processes which are under development in Europe. based on complete or partial gasification of a solid fuel in a pressurized fluidized bed. At the same time, fuel characterization data for the combination of temperature, pressure and fuel particle heating rate that is encountered in fluidized bed gasification are very scarce. In this paper, quantitative data on the characterization of fuels for advanced combustion and gasification technologies based on fluidized beds are given, as a result from the authors participation in the JOULE 2 extension project on clean coal technology of the European community. Eleven solid fuels, ranging from coal via peat to wood, have been studied under typical fluidized bed gasification conditions: 800--1,000 C, 1--25 bar, fuel heating rate in the order of 100--1,000 C/s. Carbon dioxide was used as gasifying agent. A pressurized thermogravimetric reactor was used for the experiments. The results show that the solid residue yield after pyrolysis/devolatilization increases with pressure and decreases with temperature. For coal, the gasification reactivity of the char increases by a factor of 3 to 4 when pressurizing from 1 to 25 bar, for the younger fuels such as peat and wood, this effect is negligible. Several empirical engineering equations are given which relate the fuel performance to the process parameters and the proximate and chemical analyses of the fuel. A pressure maximum was found at which a maximum gasification reactivity occurs, for practically all fuels, and depending on temperature. It is shown that this can be explained and modeled using a Langmuir-Hinshelwood model.

  6. 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.

  7. 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.

  8. Distributor for multistage fluidized beds

    SciTech Connect

    Wormser, A.

    1992-06-16

    This patent describes a multibed fluidized bed system. It comprises a fluidized bed vessel having a casing surrounding a first distributor and a second distributor downstream from the first distributor; a first bed material placed on the first distributor and a second bed material placed on the second distributor; each of the bed materials having an angle of repose; and wherein the angle formed by the substantially straight elongated tubular passages and the upper surface is less than the angle of repose of the second bed material.

  9. Mutagenicity in Salmonella of nitroorganic compounds in extracts of fly ash from a lignite-fired atmospheric fluidized-bed combustor

    SciTech Connect

    Remsen, J.F.; Harris, W.R.

    1984-01-01

    The mutagenicity of a benzene/methanol extract of fly ash from an atmospheric fluidized-bed combustor burning Beulah, ND, lignite was tested in Salmonella. Six strains were used, including three that were mutants in a nitroreductase gene locus. The numbers of revertants from his/sup -/ to his/sup +/ as a function of the amount of fly ash extracted were determined. The results showed that the major mutagens in the crude extract were nitro compounds, from the fact that reversion rates in the nitroreductase-deficient strains were significantly lower than in the parent strains from which they were derived. The responses of the three parental strains, TA1538, TA98, and TA100, were quite similar; thus no conclusions could be made about frameshift versus base-substitution mutagens. Mutagenicity of 15 fractions of the extract was also tested, and one major peak of activity was detected. This activity eluted from a high-performance liquid chromatograph outside the range of retention times associated with mononitro-aromatics. No further identification of specific nitroorganic compounds has been made. 27 references, 2 figures, 4 tables.

  10. Manual for applying fluidized-bed-combustion residue to agricultural lands. Research report

    SciTech Connect

    Stout, W.L.; Hern, J.L.; Korcak, R.F.; Carlson, C.W.

    1988-08-01

    Atmospheric fluidized-bed combustion (AFBC) is a process that reduces sulfur emissions from coal-fired electric-generating plants. The residue from the process is a mixture of alkaline oxides, calcium sulfate, and coal ash constituent. Since 1976, USDA/ARS has investigated the potential agriculture use of the residue. The investigations comprised an extensive series of laboratory, greenhouse, field plot, and animal-feeding experiments. The best and safest use of AFBC residue in agriculture was as a substitute for agricultural lime. The report contains guidelines for appling AFBC residue to agricultural lands.

  11. Apparatus and process for controlling fluidized beds

    DOEpatents

    Rehmat, Amirali G.; Patel, Jitendra G.

    1985-10-01

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

  12. 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.

  13. Review of fluidized bed combustion technology in the United States

    SciTech Connect

    Krishnan, R.P.; Daw, C.S.; Jones, J.E. Jr.

    1984-01-01

    The United States (US) initiated work in fluidized bed combustion (FBC) in the mid-1960s, with primary emphasis on industrial applications. With passage of the Clean Air Act in 1970, the environmental benefits of the technology soon attracted interest. This provided the impetus for expanded effort focused on the reduced NO/sub x/ emissions resulting from lower combustion temperature and SO/sub 2/ capture by means of chemical reaction with limestone or dolomite in the fluidized bed. The oil embargo in 1973 further stimulated interest in FBC technology. Several manufacturers presently offer atmospheric fluidized bed combustion (AFBC) and circulating fluidized bed combustion (CFBC) units for industrial application in the United States. However, FBC for electric power generation remains in the development and demonstration phase. The Tennessee Valley Authority (TVA) and Electric Power Research Institute (EPRI) are operating a 20-MW AFBC utility pilot plant and are proceeding with plans for a 160-MW(e) demonstration plant with other participants. Research has been under way on pressurized fluidized bed combustion (PFBC) at Grimethorpe in South Yorkshire, England, and within the United States at the Curtiss-Wright Pilot Plant, and at other smaller test facilities. An emerging turbocharged PFBC concept will likely stimulate more near-term interest in PFBC technology for both industrial and utility applications. The major US programs and test facilities are described; remaining technical uncertainties are discussed, and the future outlook for the technology is assessed.

  14. 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.

  15. 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.

  16. Fluidized bed desulfurization

    NASA Technical Reports Server (NTRS)

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

    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.

  17. Heat transfer in high temperature fluidized beds with immersed tubes for coal combustion service. Final report, October 1, 1977-March 31, 1981

    SciTech Connect

    Welty, J. R.

    1984-01-01

    The project involved two parts: analytical and experimental. The progression of work includes the following major divisions: analytical studies involving studies of heat transfer, hydrodynamics of gas flow within the bed, and some considerations of bubble and adjacent tube influences on the heat transfer; experimental apparatus including the instrumented tubes for heat transfer measurements, digital data acquisition, and the high temperature fluidized bed test facility; experimental results; and experimental validation of the analytical model.

  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. Engineer, design, construct, test and evaluate a pressurized fluidized bed pilot plant using high sulfur coal for production of electric power. Phase III: pilot plant construction. Annual report, July 1982-July 1983

    SciTech Connect

    Not Available

    1983-01-01

    The original Pressurized Fluidized Bed (PFB) Pilot plant contract, which included the Phase III construction of the plant, was superseded by a Cooperative Agreement on July 21, 1982. Construction activities were resumed after that date. The installation of the system for coal and dolomite receiving and storage, coal preparation, coal and dolomite injection, and ash removal, cooling and storage continued during the first annual reporting period under the Cooperative Agreement. The Control Building siding was installed and control and electrical equipment installation into this building proceeded. The in-bed heat exchanger tubes were assembled into the windbox and the assembly was installed into the PFB combustor. The hot gas cleanup devices were fabricated and installed. The process piping was fabricated and installation proceeded during this period. Installation of electrical wiring and instrumentation was initiated. The construction phase is over 90% complete. 36 figs., 3 tabs.

  20. 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.

  1. Sludge incineration in a spinning fluidized bed incinerator

    SciTech Connect

    Swithenbank, J.; Basire, S.; Wong, W.Y.; Lu, Y.; Nasserzadeh, V.

    1999-07-01

    At the present time, the sewage treatment plants in the UK produce about 25 million tonnes of sewage sludge each year at a concentration of 4% solids. New regulations forbid sea dumping and in the near future new incinerators will be required to dispose of about five million tonnes per year. Bubbling fluidized bed incinerators are widely used to burn sewage sludge at a typical consumption rate of about 0.02 kg(dry)/s/m{sup 2}, and it follows that over 300 conventional fluidized bed incinerators of 3 meters bed diameter could be required to cope with the increased demand. At Sheffield University Waste Incineration Centre (SUWIC) research work is being carried out to develop a novel spinning fluidized bed incinerator. The key factor to note is that when air flows up through a bed of near mono-sized particles, it fluidizes when the pressure drop across the bed is equal to the weight of the bed. Normally, the weight of the bed is determined by gravity. However, if the bed is contained by a cylindrical air distributor plate that is rotating rapidly about its axis, then the effective weight of the bed can be increased dramatically. The airflow passing through the bed can be increased proportionally to the g level produced by the rotation and it follows that the process has been intensified. In exploratory tests with a spinning fluidized bed the authors have achieved combustion intensities with coal combustion as high as 100 MW/m{sup 3}. A problem with burning coal is that it was difficult to remove the heat and rotating water seals had to be used to transfer cooling water into the bed. In the case of sewage and other sludges, this problem does not exist since the flue gases can remove the small amount of heat released. The rotating fluidized bed sludge incinerator is a novel device, which is very compact. It is able to solve the turndown problem encountered with conventional fluidized beds by simply changing the rotation speed. Bearing in mind that a centrifugal sludge de-watering unit is already used on sludge incineration plants, it is likely that the rotating fluidized bed can be combined with the de-watering unit, resulting in further process integration and intensification. Furthermore, the ash sintering system can be added to render the ash non-toxic and unleachable thus reducing the costs of its disposal.

  2. Engineer, design, construct, test, and evaluate a pressurized fluidized-bed pilot plant using high-sulfur coal for production of electric power: Phase III. Pilot plant construction. Quarterly report, March 1-May 31, 1981

    SciTech Connect

    Not Available

    1981-01-01

    Progress in Phase III of the Engineering Program to design, construct, test and evaluate a pressurized fluidized bed pilot plant is reported. Phase III includes pilot plant fabrication, construction and initial check out. Fabrication of the upper and lower PFB combustor vessels is being followed by a short interval schedule and delivery is projected for July 15, 1981. Fabrication of component parts of the combustor recycle loop is on schedule. The recycle cyclone, freeboard tee, recycle cyclone tee, trickle valve and upper spool piece have all been received for the installation of refractory lining. The bellows assembly is scheduled for completion on July 15, 1981. Material handling equipment purchase orders were placed for the coal handling equipment, electric elevator, coal preparation, and ash handling equipment. Fire protection specifications were issued. The overall project is 43% complete. (LCL)

  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. Combustion characteristics of rice husk in fluidized beds

    SciTech Connect

    Liu, H.; Lin, Z.; Liu, D.; Wu, W.

    1995-12-31

    Some characteristics of rice husk were studied such as the physical and chemical property, fluidization, slagging, agglomeration and pneumatic transportation properties. Chemical reaction kinetics of rice husk, much different from that of coals, was obtained on the basis of thermogravimetric experiments. Experiments were carried out with an accelerated surface area and porosimetry system to examine the microscopic structure change of rice husk and it was compared with that of coal. Combustion tests were performed on a fluidized bed combustor with a cross section of 0.2m by 0.2m. The concept of two-stage combustion of rice husk proposed is that the release of volatile matter and combustion of carbon takes place separately, which is different from that of coal. According to the combustion characteristics of rice husk, a new boiler design combining combustion styles and taking fluidized bed as the main component, is proposed. It has been licensed as a patent.

  5. Biomass fast pyrolysis for bio-oil production in a fluidized bed reactor under hot flue atmosphere.

    PubMed

    Li, Ning; Wang, Xiang; Bai, Xueyuan; Li, Zhihe; Zhang, Ying

    2015-10-01

    Fast pyrolysis experiments of corn stalk were performed to investigate the optimal pyrolysis conditions of temperature and bed material for maximum bio-oil production under flue gas atmosphere. Under the optimized pyrolysis conditions, furfural residue, xylose residue and kelp seaweed were pyrolyzed to examine their yield distributions of products, and the physical characteristics of bio-oil were studied. The best flow rate of the flue gas at selected temperature is obtained, and the pyrolysis temperature at 500 degrees C and dolomite as bed material could give a maximum bio-oil yield. The highest bio-oil yield of 43.3% (W/W) was achieved from corn stalk under the optimal conditions. Two main fractions were recovered from the stratified bio-oils: light oils and heavy oils. The physical properties of heavy oils from all feedstocks varied little. The calorific values of heavy oils were much higher than that of light oils. The pyrolysis gas could be used as a gaseous fuel due to a relatively high calorific value of 6.5-8.5 MJ/m3. PMID:26964339

  6. Staged cascade fluidized bed combustor

    DOEpatents

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

    1984-01-01

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

  7. Fluidized bed deposition of diamond

    DOEpatents

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

    1998-01-01

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

  8. Solar energy assisted fluidized bed fruit drying

    SciTech Connect

    Kilkis, B.

    1981-01-01

    This paper shows the possibility of using fluidized bed principle simply and economically when a proper design is made. With the aid of computer aided design methods, and using phenomena of local fluidization, an optimum packed bed and a fluidized bed combination was achieved in a single bed. 14 refs.

  9. 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...

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

    PubMed

    Ellis, J W

    1985-03-01

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

  11. 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.

  12. Continuous austempering fluidized bed furnace. Final report

    SciTech Connect

    Srinivasan, M.N.

    1997-09-23

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

  13. Method of feeding particulate material to a fluidized bed

    DOEpatents

    Borio, Richard W.; Goodstine, Stephen L.

    1984-01-01

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

  14. Solid fuel feed system for a fluidized bed

    DOEpatents

    Jones, Brian C.

    1982-01-01

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

  15. 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.

  16. Fluidized bed heat treating system

    SciTech Connect

    Ripley, Edward B; Pfennigwerth, Glenn L

    2014-05-06

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

  17. 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.

  18. Hot corrosion/erosion testing of materials for applications for advanced power conversion systems using coal-derived fuels. Fireside II. Evaluation of turbine materials for use in a coal-fired fluidized bed combustion environment. Task II. Final report

    SciTech Connect

    Not Available

    1980-09-01

    This report summarizes the results of the General Electric Fireside Corrosion Task II Program. This program was designed to evaluate the erosion/corrosion behavior of gas turbine nozzle guide vane and rotor blade materials in both simulated and actual pressurized fluidized bed combustor (PFBC) environments. Simulation testing included exposing disc-shaped specimens in atmospheric pressure small burner rig test stands operated at 1600/sup 0/F (871/sup 0/C) for periods up to 1300 hours. PFBC evaluation testing consisted of exposing airfoil shaped specimens to the efflux from a PFBC in a turbine test section installed in the Exxon PFBC Miniplant facility at Linden, N.J. Candidate gas turbine materials included three cast vane and blade base alloys, FSX-414, IN-738, and U-700, and one protective coating system, platinum-chromium-aluminide (RT-22). Small burner rig testing consistently showed the nickel-base alloys U-700 and IN-738 most susceptible to corrosion/sulfidation, followed by the cobalt-base alloy FSX-414; the RT-22 coating on IN-738 was most resistant to hot corrosion attack. Parts life estimates have been made for the nickel and cobalt-base alloys based on corrosion rates determined from the PFBC testing.

  19. Decontamination of combustion gases in fluidized bed incinerators

    DOEpatents

    Leon, Albert M.

    1982-01-01

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

  20. Fluidized bed heating process and apparatus

    NASA Technical Reports Server (NTRS)

    McHale, Edward J. (Inventor)

    1981-01-01

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

  1. Basic structural parameters of fluidized bed dryers

    SciTech Connect

    Filippov, V.A.

    1980-01-01

    The limits of existence of various turbulent and forced fluidization regimes are conditionally indicated. The principal structural parameters of fluidized bed dryers are determined as a function of the characteristics of the material to be dried.

  2. Drying of solids in fluidized beds

    SciTech Connect

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

    1995-09-01

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

  3. 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 ...

  4. Solar energy assisted fluidized bed fruit drying

    NASA Astrophysics Data System (ADS)

    Kilkis, B.

    The possibility of using the fluidized-bed principle for solar drying of fruits economically and simply is explored. With the aid of computerized design methods, an optimized fluidized bed/packed bed combination was achieved, that in addition functions as a solar air heater. Based on this configuration, a novel aparatus was designed in Turkey for drying Turkish grapes. Comparisons with comparable systems are made.

  5. The effect of ash and filter media characteristics on particle filtration efficiency in fluidized bed.

    PubMed

    Wey, Ming-Yen; Chen, Ke-Hao; Liu, Kuang-Yu

    2005-05-20

    The phenomenon of filtering particles by a fluidized bed is complex and the parameters that affect the control efficiency of filtration have not yet been clarified. The major objective of the study focuses on the effect of characteristics of ash and filter media on filtration efficiency in a fluidized bed. The performance of the fluidized bed for removal of particles in flue gas at various fluidized operating conditions, and then the mechanisms of collecting particles were studied. The evaluated parameters included (1) various ashes (coal ash and incinerator ash); (2) bed material size; (3) operating gas velocity; and (4) bed temperature. The results indicate that the removal efficiency of coal ash increases initially with gas velocity, then decreases gradually as velocity exceeds some specific value. Furthermore, the removal of coal ash enhance with silica sand size decreasing. When the fluidized bed is operated at high temperature, diffusion is a more important mechanism than at room temperature especially for small particles. Although the inertial impaction is the main collection mechanism, the "bounce off" effect when the particles collide with the bed material could reduce the removal efficiency significantly. Because of layer inversion in fluidized bed, the removal efficiency of incinerator ash is decreased with increasing of gas velocity. PMID:15885419

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

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

    PubMed

    You, Changfu; Xu, Xuchang

    2008-04-01

    Ventilation air methane (VAM) accounts for 60-80% of the total emissions from coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible. PMID:18505001

  13. 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.

  14. 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

  15. 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.

  16. 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.

  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

    2005-01-30

    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.

  18. 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.

  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, 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.

  20. SOLIDS TRANSPORT BETWEEN ADJACENT CAFB FLUIDIZED BEDS

    EPA Science Inventory

    The report gives results of an experimental investigation of a pulsed, dense-phase pneumatic transport system for controlled circulation between adjacent fluidized beds. A model was developed to predict performance. The program provides technical support for EPA's program to demo...

  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. Reversed flow fluidized-bed combustion apparatus

    DOEpatents

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

    1984-01-01

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

  3. Fluidization quality analyzer for fluidized beds

    DOEpatents

    Daw, C. Stuart; Hawk, James A.

    1995-01-01

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

  4. 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.

  5. 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.

  6. Modeling carbonizing process in fluidized bed

    NASA Astrophysics Data System (ADS)

    Szota, M.; Jasinski, J.

    2010-06-01

    This paper presents possibility of using neural networks model for designing carbonizing process in fluidized bed. This process is very complicated and difficult as multi-parameters changes are non linear and car drive cross structure is non homogeneous. This fact and lack of mathematical algorithms describing this process makes modeling properties of drives elements by traditional numerical methods difficult or even impossible. In this case it is possible to try using artificial neural network. Using neural networks for modeling carbonizing in fluidized bed is caused by several nets' features: non linear character, ability to generalize the results of calculations for data out of training set, no need for mathematical algorithms describing influence changes input parameters on modeling materials properties. The neural network structure is designed and special prepared by choosing input and output parameters of process. The method of learning and testing neural network, the way of limiting nets structure and minimizing learning and testing error are discussed. Such prepared neural network model, after putting expected values of car cross driving properties in output layer, can give answers to a lot of questions about running carbonizing process in fluidized bed. The practical implications of the neural network models are possibility of using they to build control system capable of on-line controlling running process and supporting engineering decision in real time. The originality of this research is different conception to obtain foreseen materials properties after carbonizing in fluidized bed. The specially prepared neural networks model could be a help for engineering decisions and may be used in designing carbonizing process in fluidized bed as well as in controlling changes of this process.

  7. 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.

  8. DESIGN AND CONSTRUCTION OF A FLUIDIZED-BED COMBUSTION SAMPLING AND ANALYTICAL TEST RIG

    EPA Science Inventory

    The report describes the design, construction, and installation of a fluidized-bed coal combustion sampling and analytical test rig in the High Bay Area (Wing G) of EPA's Industrial Environmental Research Laboratory (IERL), Research Triangle Park, North Carolina. The rig, to be u...

  9. 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...

  10. 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,...

  11. 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.

  12. 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.

  13. 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

    Bartoňová, Lucie; Klika, Zdeněk

    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

  14. 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.

  15. Coal combustor retrofits to gas- and oil-fired boilers

    SciTech Connect

    Kaplan, L.

    1982-02-22

    The Wormser Grate is an atmospheric pressure fluidized bed coal combustor designed to fire new or existing gas or oil-fired boilers of capacities from 10,000-100,000 lb/h of steam. The fluidized bed boiler produces 60% of the steam output, and the rest is produced by gas or oil firing. The Wormer Grate uses two separate, shallow fluidised beds: one for combustion and the other for desulphurization.

  16. NYU-DOE Pressurized Fluidized Bed Combustor Facility

    SciTech Connect

    Zakkay, V.; Kolar, A.; Sellakumar, K.; Srinivasaragavan, S.; Miller, G.; Panunzio, S.; Joseph, A.; Sundaresan, C.

    1983-01-01

    New York University (NYU), under a Department of Energy (DOE) Contract, has designed and constructed a sub-pilot scale Pressurized Fluidized-Bed Combustor (PFBC) Facility at the Antonio Ferri Laboratories, Westbury, Long Island. The basic feature of this Experimental Research Facility is a well-instrumented, 30-inch diameter coal combustor capable of operating up to 10 atm and provided with a liberal number of ports, making it a versatile unit for study of fundamental in-bed phenomena. Additionally, the overall design features make it a flexible facility for solving a variety of industrial research problems. The main objectives of the facility are two-fold: (1) to perform research in important areas of Pressurized Fluidized-Bed Combustion like low-grade fuel combustion under pressure; and (2) to provide the PFBC community with a experimental research tool for basic and applied research in order to accelerate the commercialization of this technology. New York University will initially test the facility of burning low-grade fuels under pressure. During the test program, emphasis will be placed on burning North Dakota lignite under pressures up to 7 atm. The performance of lignite with regard to its feeding, combustion efficiency, sulfur adsorption and sorbent requirements will be investigated. This report describes the various systems of the PFBC facility and operating procedures, and presents an outline of the test program planned for the facility. Other details are provided in the Equipment and Maintenance Manual, Test Program and Data Acquisition Manual, and Training Manual.

  17. 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.

  18. Bed material agglomeration during fluidized bed combustion

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.

    1993-02-01

    The purpose of this project is to determine the physical and chemical reactions which led to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. Survey of industrial-scale fluidized bed combustors is being conducted to determine the occurrence of bed agglomeration and the circumstances under which agglomeration took place. This task should be finished by the end of February. Samples of bed material, agglomerate material, and boiler deposits are being requested from boiler operators as part of the survey. Once received, these sample will be analyzed to determine chemical and mineralogic composition. The bulk chemical determination will be performed using x-ray fluorescence and inductively coupled plasma-optical emission (ICP). Mineralogy will be detected by x-ray diffraction (XRD). Chemical and mineral reactions will be determined by scanning electron microscopy, optical microscopy, and electron microprobe.

  19. Rapid ignition of fluidized bed boiler

    DOEpatents

    Osborn, Liman D.

    1976-12-14

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

  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. Fluidized bed silicon deposition from silane

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  2. 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.

  3. Engineer, design, construct, test and evaluate a pressurized fluidized bed pilot plant using high sulfur coal for production of electric power. Phase III. Pilot plant construction. Final report

    SciTech Connect

    Not Available

    1984-11-01

    This final report describes the coal-fired plant design capable of producing electric power in an environmentally clean manner. The report presents the predicted performance using high sulfur bituminous coal and summarizes the construction activities and changes through completion on November 30, 1983. The construction activities involved: (1) the site excavation and pouring foundations for the PFB process equipment structural tower, control building, dolomite silo, boost compressor, and various equipment footings; (2) the fabrication and erection of the support steel work for the process equipment tower, control building, rail car thaw shed, and particulate scrubber and exhaust stack; (3) the fabrication and erection of the process equipment including the PFB combustor vessel, windbox, in-bed heat exchanger and process piping, the ash recycle system, the gas clean-up system, the ash removal, cooling and storage system, the coal handling, preparation and injection systems, the dolomite receiving, handling, storage and injection systems, the boost air compressor, dryer and receiver systems, the purge instrument and service air systems, the control, instrument and electrical systems, the tower elevator, the cardox, Halon and water fire protection system, etc. In addition, modifications and refurbishment were completed on the existing equipment at the site which was incorporated into the Pilot Plant system. Finally, plans were prepared describing the operating procedures, maintenance requirements, spare parts list, training program and manpower requirements for the proposed Phase IV test evaluation program. 37 figures, 11 tables.

  4. 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.

  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. Measurement of bubble size in fluidized beds

    SciTech Connect

    Viswanathan, K.; Subba Rao, D.

    1984-07-01

    A simple method is developed to estimate bubble size variation with height in fluidized beds from axial pressure measurements. Experiments are performed and results are presented to indicate the procedure of using the method developed. Bubble sizes thus obtained compare reasonably well with available bubble growth correlations. The present method is expected to be useful for bubble size measurements at high temperatures and pressures and under complex reacting conditions.

  7. 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.

  8. 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.

  9. Dynamics of a shallow fluidized bed

    SciTech Connect

    Tsimring, Lev S.; Ramaswamy, Ramakrishna; Sherman, Philip

    1999-12-01

    The results of the experimental study of the dynamics of a shallow fluidized bed are reported. The behavior of granular material is controlled by the interplay of two factors--levitation due to the upward airflow, and sliding back due to gravity. Near the threshold of instability, the system shows critical behavior with remarkably long transient dynamics. The experimental observations are compared with a simple cellular automata model. (c) 1999 The American Physical Society.

  10. Cluster Dynamics in a Circulating Fluidized Bed

    SciTech Connect

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

    2006-11-01

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

  11. Fluidized-bed combustion of oil shale

    SciTech Connect

    McCarty, H.E.

    1983-04-01

    Two sets of fluidized-bed combustion experiments have been conducted in which raw shale fines and a simulated low Btu off-gas were burned to produce steam for power generation. The results show that the shale fines and low Btu off-gas can be utilized for energy production, and further, the sulfur removal is effective and efficient. This process eliminates the need for H/sub 2/S removal and is not sensitive to small quantities of entrained liquids.

  12. Particle pressures in fluidized beds. Annual report

    SciTech Connect

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

    1994-03-01

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

  13. 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.

  14. 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.

  15. 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.

  16. Single-stage fluidized-bed gasification

    NASA Astrophysics Data System (ADS)

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

    1982-04-01

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

  17. 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.

  18. Hydrodynamic aspects of a circulating fluidized bed with internals

    SciTech Connect

    Balasubramanian, N.; Srinivasakannan, C.

    1998-06-01

    An attempt is made to examine the influence of internals (baffles) in the riser of the circulating fluidized bed. Experiments are conducted in a circulating fluidized bed, having perforated plates with different free areas. It is noticed from the present work that a circulating fluidized bed having 45% free area gives uniform solids concentration and pressure drop along the length of the riser. In addition to the uniformity, the circulating fluidized bed with internals gives higher pressure drop (solids concentration) compared to a conventional circulating fluidized bed. For internals having 67.6% free area the pressure drop is higher at the lower portion of the riser compared to the upper portion, similar to a conventional circulating fluidized bed. For 30% free area plates the solids concentration varies axially within the stage and remains uniform from stage to stage.

  19. 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...

  20. 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...

  1. 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).

  2. Engineer, design, construct, test, and evaluate a pressurized fluidized-bed pilot plant using high-sulfur coal for production of electric power. Phase III: construction. Annual report, March 1, 1980-February 28, 1981

    SciTech Connect

    Not Available

    1981-01-01

    Progress in the construction of the 13 MW pressurized fluidized bed (PFB) pilot plant at Wood-Ridge, NJ is reported. Excavation at the site began in November 1980. Steel fabrication is continuing with steel erection scheduled for May 1981. Procurement of mechanical equipment, especially materials handling equipment is underway. Contracts have been let for the gas turbine components and for the manufacture of the PFB process components. (LCL)

  3. 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.

  4. Development of a FI CIRC{trademark} fluidized bed boiler to burn waste tires

    SciTech Connect

    Dervin, C.; Waldron, D.J.; Haas, J.C.

    1997-12-31

    Disposal of tires is becoming a problem due to higher landfill charges and environmental concerns. Typically tires have a higher calorific value than coal, contain less nitrogen, ash, and sulfur than most coals and are a potential source of energy for power and process steam generation. In 1995 a Fines Circulating (FI CIRC{trademark}) fluidized bed boiler was selected to burn tires for a project in the city of Fulton, Illinois. Fuels ranging from Petroleum Coke to Brown coal had already been successfully fired in commercial plants and preliminary pilot plant testing showed no problems in firing tires. During the development of the project, financiers raised concerns about the optimum fuel size, combustion characteristics, removal of wires from the fluidized bed, and the control of emissions from the plant. A testing program was devised which included hot and cold pilot plant testing to evaluate the characteristics of firing shredded tires. The results and the impact on the boiler design are presented.

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

    DOEpatents

    Cole, Rossa W.; Zoll, August H.

    1982-01-01

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

  6. Electrode assembly for a fluidized bed apparatus

    DOEpatents

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

    1976-11-23

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

  7. Pyrolysis reactor and fluidized bed combustion chamber

    DOEpatents

    Green, Norman W.

    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.

  8. Packed fluidized bed blanket for fusion reactor

    DOEpatents

    Chi, John W. H.

    1984-01-01

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

  9. Gas fluidized-bed stirred media mill

    DOEpatents

    Sadler, III, Leon Y.

    1997-01-01

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

  10. 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.

  11. Transients in a circulating fluidized bed boiler

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  12. 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.

  13. Analysis and modeling of in-bed tube erosion in a gaseous fluidized bed

    SciTech Connect

    Lee, S. W.

    1989-01-01

    Erosion by impingement of bed materials (ash, coal, and sorbents) on in-bed components has caused serious problems to many fluidized bed combustion (FBC) systems in the past few decades. The author conducted an experimental study, supplemented with theoretical analysis, in which erosion-prone tubes were placed inside a fluidized bed of uniformly sized glass beads to accelerate the mass removal process of the in-bed tubes. Effects of tube-to-distributor clearance, superficial velocity, tube orientation and location, tube circumferential angle, tube bundle height and configuration, and particle size on tube erosion were investigated, identified and discussed. It was found that tube erosion occurred only at a threshold fluidizing velocity (26 cm/s), close to the minimum fluidizing velocity (19 cm/s), and increased almost linearly with increasing superficial velocity. The average specific erosion rate of a tube bundle was about one order of magnitude lower than that of a single tube under the same test conditions. The erosion of a staggered bundle was found larger by 45% than that of an in-line bundle having identical tube pitches. Mathematical modeling of gas-particle flow in the fluidized bed with an in-bed tube was pursued to explore the particle motion and its effect on tube erosion. An erosion model was developed to describe and analyze the phenomenon of in-bed tube erosion. A series of improved electrostatic impact probes, based on the triboelectric effect of moving particles, were developed and used as a primary standard for measuring the particle-surface collision frequency in the fluidized bed. Design guidelines were proposed for fluidized bed systems for planning counter measures against in-bed tube erosion.

  14. 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....

  15. 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....

  16. 21 CFR 890.5160 - Air-fluidized bed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  17. Modeling of gasification behavior in freeboard of fluidized bed gasifier

    SciTech Connect

    Tang Zhong; Zhang Jianmin; Wang Yang; Zhang Bijiang

    1997-12-31

    The freeboard, the large room above the dense bed surface where the solid density is low compared with dense phase, is a very important construction part in most fluidized bed reactors. The purpose of a freeboard design is to control the fine particles entrained by gas stream from dense phase. It is well known that the gas entrainment ability is proportion to gas velocity; in order to reduce the gas velocity, the size of freeboard is enlarged. Meanwhile, the height of freeboard is larger than the transport disengaging height so as to decrease large particle being carried out of the bed. In a fluidized bed reactor, the reaction seldom occurs in the freeboard because of the low solid hold-up. The freeboard is always omitted when considering the reaction in a fluidized bed reactor and simulation of the fluidized bed reactor. On the other hand, in some kinds of fluidized bed reactors, such as a fluidized bed gasifier, there must be a freeboard. A mathematical model has been developed for investigating the gasification behavior in the freeboard of a fluidized bed gasifier. In this model, Monte-Carlo method was used to describe the particle movement in the freeboard. Comparing the simulation results with experiment data, it can be seen that the freeboard has little effect on gasification reaction in fluidized bed gasifier under the conditions of no fines recycling. Some recommendations were given to improve the freeboard reaction ability in this article.

  18. 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....

  19. 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....

  20. Fermentation in a fluidized-bed reactor

    SciTech Connect

    Scott, C.D.

    1983-06-01

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

  1. 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.

  2. Grout stability and strength requirements for field scale injection of fluidized bed combustion ash grout

    SciTech Connect

    Ziemkiewicz, P.F.; Black, C.; Gray, D.D.; Siriwardane, H.J.; Hamric, R.

    1998-12-31

    This paper presents the results of a study involving a field scale injection of a grout made of Fluidized Bed Combustion Ash to control acid mine drainage and subsidence at an abandoned room and pillar coal mine. The grout mix was developed from results obtained from several laboratory scale experiments conducted to investigate flow characteristics and strength of the grout. Based on the rheological properties of the candidate grout mixes it was determined that admixtures were needed to stabilize the grout for optimum flow characteristics. Strength requirements for the grout were determined from site specific geologic information and expected stress levels. One thousand cubic yards of the candidate grout were pumped into an inactive panel of an active room and pillar coal mine to investigate the field performance of the grout. The field study showed that a grout made of Fluidized Bed Combustion ash can be successfully pumped to backfill the mine void.

  3. Industrial-hygiene characterization of fluidized-bed-combustion processes. Final report

    SciTech Connect

    McHugh, J.; Trinosky, V.; Golembiewski, M.

    1985-12-01

    The objective of the study was to characterize current or potential occupational health problems of the fluidized-bed-combustion process. The assessment described was based on in-depth industrial-hygiene surveys at three fluidized-bed-boiler (FBB) facilities selected to represent the industry. The results from the surveys demonstrate limited potential for occupational exposure to airborne contaminants. None of the air contaminants monitored exceeded OSHA Permissible Exposure Limits. Only sulfur dioxide, coal-tar-pitch volatiles, and nuisance dust approached the recommended ACGIH Threshold Limit Values. Mutagenic activity was found in high volume and bulk samples at two of the sites and appeared to correlate roughly with the air concentration of coal-tar-pitch volatiles detected.

  4. 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.

  5. 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.

  6. System design study to reduce capital and operating costs and bench-scale testing of a circulating-bed AFB [atmospheric pressure fluidized bed] advanced concept: Phase 1, Design, cost estimate, and cost comparison for MWK circulating fluid bed combustor and oil-fired boilers: Final report

    SciTech Connect

    Sadhukhan, P.; Lin, Y.Y.; Hsiao, K.H.; Richards, S.R.; Wagner, C.; Settle, W.H.; Bryant, J.; Gorman, W.A.; Newlin, T.; Shires, P.J.; James, J.L.

    1986-06-01

    The Department of Energy (DOE) issued an RFP for a "System Design Study to Reduce Capital and Operating Cost and Bench Scale Testing of a Circulating-Bed AFB Advanced Concept." The design and cost study of a 150,000 pounds per hour steam boiler comprised Phase-I of the RFP. The objective was to produce a design with improved performance and reduced capital and operating costs compared with conventional atmospheric pressure fluidized bed (AFB) boilers. The final result was a significant reduction of capital cost - 36% below the lowest AFB plant cost. The steam cost was 24% below the corresponding cost for the AFB process. In June 1985, DOE issued a Change Order (C001) to the Phase-I study in order for MWK to design and estimate the cost for a scaled-down coal-fired (Illinois No. 6, 3% S) CFBC plant producing low pressure and low temperature steam (75,000lbs/hr, 200 psig, 387{degree}F), and to compare the costs -capital and steam costs -with those for a packaged high sulfur (3%) fuel oil-fired boiler, which is of the same capacity and requires SO{sub 2} removal. An additional objective was to estimate the cost for a No. 2 fuel oil-fired boiler that does not need any SO{sub 2} scrubber. An evaluation of the sensitivity of the steam cost to the oil-fired boiler capital cost and to fuel prices was also to be undertaken. The cost of steam produced by the No. 6 fuel oil boiler is 52% higher than the cost for CFBC, and the corresponding cost for the No. 2 fuel oil plant is 43% higher. Again, a large advantage for the CFBC comes from the low price of coal relative to that of oil. The large cost advantage of steam calculated for the MWK CFBC using coal as a fuel over the oil-fired boilers would remain even in the worst case scenario of a declining oil price accompanied by a steady coal price. 7 refs., 25 figs., 34 tabs.

  7. Modeling biomass gasification in circulating fluidized beds

    NASA Astrophysics Data System (ADS)

    Miao, Qi

    In this thesis, the modeling of biomass gasification in circulating fluidized beds was studied. The hydrodynamics of a circulating fluidized bed operating on biomass particles were first investigated, both experimentally and numerically. Then a comprehensive mathematical model was presented to predict the overall performance of a 1.2 MWe biomass gasification and power generation plant. A sensitivity analysis was conducted to test its response to several gasifier operating conditions. The model was validated using the experimental results obtained from the plant and two other circulating fluidized bed biomass gasifiers (CFBBGs). Finally, an ASPEN PLUS simulation model of biomass gasification was presented based on minimization of the Gibbs free energy of the reaction system at chemical equilibrium. Hydrodynamics plays a crucial role in defining the performance of gas-solid circulating fluidized beds (CFBs). A 2-dimensional mathematical model was developed considering the hydrodynamic behavior of CFB gasifiers. In the modeling, the CFB riser was divided into two regions: a dense region at the bottom and a dilute region at the top of the riser. Kunii and Levenspiel (1991)'s model was adopted to express the vertical solids distribution with some other assumptions. Radial distributions of bed voidage were taken into account in the upper zone by using Zhang et al. (1991)'s correlation. For model validation purposes, a cold model CFB was employed, in which sawdust was transported with air as the fluidizing agent. A comprehensive mathematical model was developed to predict the overall performance of a 1.2 MWe biomass gasification and power generation demonstration plant in China. Hydrodynamics as well as chemical reaction kinetics were considered. The fluidized bed riser was divided into two distinct sections: (a) a dense region at the bottom of the bed where biomass undergoes mainly heterogeneous reactions and (b) a dilute region at the top where most of homogeneous reactions occur in gas phase. Each section was divided into a number of small cells, over which mass and energy balances were applied. Due to the high heating rate in circulating fluidized bed, the pyrolysis was considered instantaneous. A number of homogeneous and heterogeneous reactions were considered in the model. Mass transfer resistance was considered negligible since the reactions were under kinetic control due to good gas-solid mixing. The model is capable of predicting the bed temperature distribution along the gasifier, the concentration and distribution of each species in the vertical direction of the bed, the composition and lower heating value (LHV) of produced gas, the gasification efficiency, the overall carbon conversion and the produced gas production rate. A sensitivity analysis was performed to test its response to several gasifier operating conditions. The model sensitivity analysis showed that equivalence ratio (ER), bed temperature, fluidization velocity, biomass feed rate and moisture content had various effects on the gasifier performance. However, the model was more sensitive to variations in ER and bed temperature. The model was validated using the experimental results obtained from the demonstration plant. The reactor was operated on rice husk at various ERs, fluidization velocities and biomass feed rates. The model gave reasonable predictions. The model was also validated by comparing the simulation results with two other different size CFBBGs using different biomass feedstock, and it was concluded that the developed model can be applied to other CFBBGs using various biomass fuels and having comparable reactor geometries. A thermodynamic model was developed under ASPEN PLUS environment. Using the approach of Gibbs free energy minimization, the model was essentially independent of kinetic parameters. A sensitivity analysis was performed on the model to test its response to operating variables, including ER and biomass moisture content. The results showed that the ER has the most effect on the product gas composition and LHV. The simulation results were compared with the experimental data obtained from the demonstration plant. Keywords: Biomass gasification; Mathematical model; Circulating fluidized bed; Hydrodynamics; Kinetics; Sensitivity analysis; Validation; Equivalence ratio; Temperature; Feed rate; Moisture; Syngas composition; Lower heating value; Gasification efficiency; Carbon conversion

  8. 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.

  9. Fluidized bed boiler having a segmented grate

    DOEpatents

    Waryasz, Richard E.

    1984-01-01

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

  10. Advanced control strategies for fluidized bed dryers

    SciTech Connect

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

    1999-11-01

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

  11. Fluidized bed silicon deposition from silane

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  12. 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.

  13. Research on acting mechanism and behavior of a gas bubble in the air dense medium fluidized bed

    SciTech Connect

    Tao, X.; Chen, Q.; Yang, Y.; Chen, Z.

    1996-12-31

    Coal dry beneficiation with air-dense medium fluidized bed has now been established as a high efficiency dry separation technology, it is the application of fluidization technology to the coal preparation field. The tiny particle media forms an uniform and stable fluidized bed with a density acted by airflow, which is used to separate 80{micro}m to {approximately}6mm size coal. This technology has achieved satisfied industrialization results, and attracted the expert`s attention in the field. In fluidized bed, the interaction between gas and solid was mainly decided by the existence state of heavy media particles mass (position and distance) relative velocity of gas-solid two phase, as well turbulent action. A change of vertical gas-solid fluidizing state essentially is the one of a energy transforming process. For a coal separating process with air-dense medium fluidized bed, the gas bubble, producing a turbulent and stirring action in the bed, leads to two effects. It can promote a uniform distribution of heavy media particles, and a uniform and stability of a bed density. Otherwise it will decrease effective contacts between gas-solids two phases, producing a bigger gas bubble. Therefore controlling a gas bubble size in bed should be optimized. This paper analyzes mutual movement between gas-solid, and studies the gas bubble behavior in the bed. A mechanic mode and a separating process of coal in the bed is discussed. It aims to research the coal separating mechanism with air-dense fluidized bed.

  14. 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.

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

    SciTech Connect

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

    1981-01-01

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

  16. Model of Fluidized Bed Containing Reacting Solids and Gases

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Lathouwers, Danny

    2003-01-01

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

  17. 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.

  18. 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.

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

    DOEpatents

    Mehta, Gautam I.; Rogers, Lynn M.

    1983-12-20

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

  20. Fluidized-bed retrofit a practical alternative to FGD

    SciTech Connect

    Stringfellow, T.E.

    1984-02-01

    A comparison is made between the costs of flue-gas desulphurization retrofit to a 112 MW pf-fired boiler, fluidized-bed combustion retrofit to the boiler, and a new fluidized-bed boiler. Breakdowns are given for capital costs, operating and maintenance costs and the busbar cost of energy for a 20 year unit life. The analysis shows that fbc is a viable option for the retrofit of many existing boilers from both a technical and economic viewpoint.

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

    SciTech Connect

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

    1997-12-01

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

  2. Engineer, design, construct, test, and evaluate a pressurized fluidized-bed pilot plant using high-sulfur coal for production of electric power. Phase III. Pilot plant construction. Quarterly report, March 1-May 31, 1982

    SciTech Connect

    Not Available

    1982-01-01

    Phase III of the Engineering Program to design, construct, test and evaluate a pressurized fluidized bed pilot plant was initiated in April 1979. Pilot plant procurement, fabrication, and construction is included within Phase III. Program accomplishments during the period of March 1 through May 31, 1982 and current status are summarized. Major items of activity during the reporting period were: installation of the windbox instrumentation was completed and the windbox was delivered on March 2, 1982; electrical and controls design work including updating of the process and instrument diagrams, loop diagrams, instrument index, and technical specifications is in process; heat exchanger tube fabrication continues on schedule with a total of 150 tubes completed; fabrication of the air exchange housing progresses; and additional material handling equipment has been received at the construction site. Over 97% of the equipment has been received.

  3. Engineer, design, construction, test and evaluate a pressurized fluidized bed pilot plant using high sulfur coal for production of electric power. Phase III. Pilot plant construction. Quarterly report, June 1-August 31, 1981

    SciTech Connect

    Not Available

    1981-01-01

    Phase III of the Engineering Program to design, construct, test and evaluate a pressurized fluidized bed pilot plant was initiated on May 19, 1980. Pilot plant fabrication, construction and limited check-out is included within Phase III. Program accomplishments during the period of June 1 through August 31, 1981 and current status are summarized and include: reviews of specifications and vendor drawings of components; fabrication of windbox hardware; erection of PFB Building structural steel was completed except for steel scheduled to be erected after installation of the recycle loop and material; the PBF combustor upper vessel was set in the PFB Building steel structure on schedule; component installation in the PFB building; the refractory lining of the PFB combustor upper vessel was completed. Bids for installing special equipment are being reviewed. (LCL)

  4. Engineer, design, construct, test and evaluate a pressurized fluidized bed pilot plant using high sulfur coal for production of electric power. Phase III. Pilot plant construction. Quarterly report for the period September 1-November 30, 1981

    SciTech Connect

    Not Available

    1981-01-01

    Progress in the design, construction, testing and evaluation of a pressurized fluidized bed pilot plant is reported. The initial layout of the main control panel arrangement was completed. Refinements to the front panel equipment arrangement and designation of cable penetration locations are in progress. Parts and materials have been specified and are being procured. Engineering design of the process piping has been completed and fabrication is awaiting FY 82 funding. The replacement ASTM A105 material flanges for the air exchange housing have been successfully welded to the stainless steel 409 housings. Fabrication of the air exchange housing is continuing on schedule. Heat exchange tube fabrication at Curtiss-Wright continues on schedule. A significant quantity of the material handling equipment has been received at site with the remainder scheduled for delivery in December/January. Initial review of the hot gas cleanup collector design drawings has been completed.

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

    SciTech Connect

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

    1992-09-01

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

  6. Abatement of N{sub 2}O emissions from circulating fluidized bed combustion through afterburning

    SciTech Connect

    Gustavsson, L.; Leckner, B.

    1995-04-01

    A method for the abatement of N{sub 2}O emission from fluidized bed combustion has been investigated. The method consists of burning a secondary fuel after the normal circulating fluidized bed combustor. Liquefied petroleum gas (LPG), fuel oil, pulverized coal, and wood, as well as sawdust, were used as the secondary fuel. Experiments showed that the N{sub 2}O emission can be reduced by 90% or more by this technique. The resulting N{sub 2}O emission was principally a function of the gas temperature achieved in the afterburner and independent of afterburning fuel, but the amount of air in the combustion gases from the primary combustion also influences the results. No negative effects on sulfur capture or on NO or CO emissions were recorded. In the experiments, the primary cyclone of the fluidized bed boiler was used for afterburning. If afterburning is implemented in a plant optimized for this purpose, an amount of secondary fuel corresponding to 10% of the total energy input should remove practically all N{sub 2}O. During the present experiments the secondary fuel consumption was greater than 10% of the total energy input due to various losses.

  7. 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.

  8. 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.

  9. 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.

  10. 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)

  11. Exploratory and basic fluidized-bed combustion studies. Quarterly report, October-December 1979

    SciTech Connect

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

    1980-11-01

    These laboratory- and process-development-scale studies support the Fossil Energy development program for atmospheric and pressurized fluidized-bed combustion. The objective of the current program is to investigate methods for improving the utilization of limestone for SO/sub 2/ emission control in FBCs and to develop a method for predicting the performance in AFBC's and PFBC's of limestones from different sources. This report presents results from (1) an investigation of the use of water treatment of spent partially sulfated limestone to enhance its SO/sub 2/ capture capacity, (2) studies of the kinetics of the hydration of spent limestone, and (3) studies of the attrition and elutriation of limestones in fluidized beds. Results of studies of the particle-removal efficiency of the TAN-JET cyclone are also reported.

  12. 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.

  13. 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.

  14. The pyrolysis of oil sands in a fluidized bed at reduced pressure

    SciTech Connect

    Fletcher, J.V.

    1992-01-01

    A fluidized bed pyrolysis reactor system was designed, constructed, and tested at reactor pressures less than atmospheric using mined and crushed oil sands from the Whiterocks deposit of Utah. A 6.0 inch ID fluidized bed reactor was fed oil sand of 7% bitumen saturation on a continuous basis while maintaining a bed height of approximately 12 inches. Spent sand was withdrawn using a modified nonmechanical L valve. The characteristics of bed pressure drop, [Delta]P[sub B], versus superficial gas velocity, U, were determined during fluidization and defluidization of spent sand using laboratory air. A proposed method for interpreting the minimum fluidization gas velocity, U[sub mf], from [Delta]P[sub B] versus U curves for multisized particles at reduced pressure was tested. U[sub mf] values were consistent with predictive correlations in the literature. The relationship, U[sub mf] T[sup 0.27] = a constant, was tested and found to be valid from 295 K to 559 K for spent sand fluidized by air. The reactor used propane for heating and the hot propane combustion product gases for fluidization during pyrolysis. Liquid products were condensed and filtered using commercial basket strainers modified with water cooling coils. Material balances of 90% or more were obtained for pyrolysis experiments at 450[degrees]C, 475[degrees]C, and 500[degrees]C. The optimum pyrolysis temperature for liquid yields was found to be 475[degrees]C at average retention times of thirty minutes or more. For pyrolysis temperatures of 475[degrees]C or lower, recovered oil sand pyrolysis products were 88 wt% liquid, 9 wt% coke, and 3 wt% gas. Liquid yields from the fluidized bed pyrolysis of Whiterocks oil sands at reduced pressure were greater than reported yields from a rotary kiln or an atmospheric pressure fluidized bed. Coke on the spent sand was about 0.6 wt% of the spent sand and represented about 8 wt% of the bitumen pyrolyzed.

  15. Biological treatment of nitrate wastewater using fluidized-bed bioreactors

    SciTech Connect

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

    1981-01-01

    Fluidized-bed bioreactors were tested as processes for denitrifying process wastewaters at flows of 23 m/sup 3//d (0.2-m-diam column) and 166 m/sup 3//d (0.5-mm-diam column). A mixed denitrifying culture obtained from garden soil was used as an inoculum for the bioreactors; films of denitrifying bacteria were allowed to form on 0.25 to 0.50-mm-diam anthracite coal particles that were fluidized in the bioreactor. As average nitrate concentrations were increased from ca. 1000 to 2500 g/m/sup 3/, denitrification rates increased from 25 to 48 kg nitrate-nitrogen/d m/sup 3/ for 11-min hydraulic retention times. These rates appeared to be independent of column diameter. Two 0.2-m-diam bioreactors operated in series on influent nitrate concentrations of 2000 g/m/sup 3/ could produce nitrate effluent concentrations less than or equal to 44 g/m/sup 3/.

  16. 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.

  17. EFFECT OF SO2 EMISSION REQUIREMENTS ON FLUIDIZED-BED COMBUSTION SYSTEMS: PRELIMINARY TECHNICAL/ECONOMIC ASSESSMENT

    EPA Science Inventory

    The report gives results of a preliminary technical/economic evaluation to project the impact of SO2 control requirements (up to 90% control) on the capital and energy costs of atmospheric-pressure and pressurized fluidized-bed combustion (AFBC and PFBC) power plants. Ability of ...

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

    DOEpatents

    Isaksson, J.; Koskinen, J.

    1995-08-22

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

  19. Method and means for controlling the operation of fluidized bed combustion apparatus

    SciTech Connect

    Caplin, P.B.; Harman, M.

    1981-10-20

    The specification describes a method and means for controlling operation of a fluidized bed combustion apparatus. In the proposals embodied in the invention the supply of combustion air fed to the fluidized bed is augmented by inert gas (Preferably waste gas taken from a low temperature outlet of the apparatus) and the proportion of inert gas used to augment the combustion supporting air is variable in dependence upon the temperature of the fluidized bed in the apparatus and/or the thermal demand placed upon the apparatus. In described embodiments of means enabling the invention to be effected arrangements are described including an induced draft fan, coupled to the outlet for waste gas of the apparatus, for feeding waste gas to a mixer and the use of a two input mixer fan coupled to both atmosphere and a waste gas supply line connected to a waste gas outlet. The volume of waste gas supplied is controllable in dependence upon the temperature of the bed in the apparatus and/or the thermal demand placed on the apparatus. The rate at which fuel is fed to the apparatus may also be controlled in dependence upon the thermal demand placed on the apparatus.

  20. 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.

  1. 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)

  2. Theoretical study of fluidized-bed drying with microwave heating

    SciTech Connect

    Wang, Z.H.; Chen, G.

    2000-03-01

    A mathematical model of heat and mass transfer is developed for fluidized-bed drying with microwave heating. The numerical results show that the temperature is uniformly distributed within a particle and that the pressure distribution in the particle has a significant effect on microwave fluidized-bed drying. The electric field strength E is an important parameter affecting the magnitude and distribution of the moisture, temperature, and pressure within a particle. At E = 10,000 V/m, a pressure difference of 1.3 MPa and a temperature of over 300 C are obtained. Microwave fluidized-bed drying is capable of a much higher drying rate than conventional fluidized-bed drying, while it also maintains a low particle temperature. At a constant E, the drying time increases initially with the working load but gradually reaches a constant because of the limited moisture-carrying capacity of gas. The microwave power adsorbed by the particles decreases during the drying process, and some of the microwave energy can be lost to the fluidized gas for certain operating conditions. Although the advantage of a high heat- and mass-transfer coefficient associated with the fluidized bed does not contribute to water evaporation at a high load, fluidization is still important for achieving better product quality and a slightly higher drying rate when compared with microwave fixed-bed drying.

  3. Fluidized bed gasification of industrial solid recovered fuels.

    PubMed

    Arena, Umberto; Di Gregorio, Fabrizio

    2016-04-01

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

  4. Fluidized-bed energy technology for biomass conversion

    SciTech Connect

    Soltes, E.J.; Lepori, W.A.; Pollock, T.C.

    1982-01-01

    Fluidized-bed technology offers several unique features for use in small-scale biomass energy conversion. Results are reported in the use of a 61-cm fluidized-bed reactor for combustion and on the use of 61-, 30-, and 5-cm reactors for gasification. combustion trials using agricultural biomass feeds have identified several problem areas. Slagging and fouling can occur at bed temperatures as low as 760/sup 0/C. Moreover, metal coupons placed in the hot exhaust gas stream experienced high rates of corrosion and erosion. Gasification experiments have confirmed that a fluidized bed will accept a wide range of biomass feeds (rice hulls, corncobs, sorghum stalks, cottom gin trash) and convert them into a low-Btu combustible gas. Slagging and fouling were not as severe when operating the fluidized bed in the gasification mode. Gas cleanup requirements as well as technical needs in evaluating corrosion of reactor construction materials are identified. Coupling of the 61-cm reactor to a steam boiler is described. Finally, the nature of fluidized-bed technology suggests potentials for biomass pyrolysis, and such use is examined. 2 figures, 5 tables.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

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

    DOEpatents

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

    1978-01-01

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

  11. 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.

  12. 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.

  13. 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/).

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

    DOEpatents

    Yang, Ralph T.; Steinberg, Meyer

    1980-01-01

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

  15. Fluidized-bed boilers for industrial sized power house

    SciTech Connect

    Siskind, W.

    1980-01-01

    This paper is concerned with fluidized-bed combustion in which a contained mass of solid particles is transformed into a pseudo fluid state by a vertical stream of air passing through it. The force of the air velocity on the particles must be sufficiently great to counteract gravitational forces but not so great as to transport the entire bed of particles along with the air stream. Under these conditions, the bed of solid particles behaves as a highly turbulent, boiling, fluid. A brief review of legislative requirements related to environmental protection is followed by description of fluidized-bed boilers design along with their operations.

  16. 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.

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

    DOEpatents

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

    1981-01-01

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

  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. 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.

  20. 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.

  1. 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.

  2. 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 ...

  3. 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 ...

  4. Heat exchanger support apparatus in a fluidized bed

    DOEpatents

    Lawton, Carl W.

    1982-01-01

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

  5. 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.

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

    SciTech Connect

    Saxena, S.C.; Rehmat, A.

    1980-12-01

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

  7. 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.

  8. Clean coal technology

    NASA Astrophysics Data System (ADS)

    Richards, P. C.; Wijffels, J.-B.; Zuideveld, P. L.

    The different commercially available clean coal technologies are introduced with particular emphasis on their efficiency and environmental performance. The technologies in question are: pulverized fuel combustion with flue gas desulphurization; circulating fluidized bed combustion; integrated coal gasification combined cycle; pressurized fluidized bed combustion. Consideration is also be given to emerging coal combustion technologies.

  9. Flash hydrogenation of coal

    DOEpatents

    Manowitz, Bernard; Steinberg, Meyer; Sheehan, Thomas V.; Winsche, Warren E.; Raseman, Chad J.

    1976-01-01

    A process for the hydrogenation of coal comprising the contacting of powdered coal with hydrogen in a rotating fluidized bed reactor. A rotating fluidized bed reactor suitable for use in this process is also disclosed. The coal residence time in the reactor is limited to less than 5 seconds while the hydrogen contact time is not in excess of 0.2 seconds.

  10. 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.

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

    DOEpatents

    Kasper, Stanley

    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.

  12. Fluidized-bed boiler assessment for Navy applications. Final report, October 1983-September 1985

    SciTech Connect

    Fu, T.T.; Maga, G.F.

    1986-11-01

    This report discusses the assessment of one of the most-promising coal-firing technologies - Fluidized-Bed Combustion(FBC) - for Navy stationary boilers. The working principles, physical construction, major and auxiliary components, and system performance of an FBC boiler are described and compared with the conventional stoker and pulverized-coal fired boilers. The advantages of the FBC boiler based on fuel flexibility, operational reliability, economic feasibility, and environmental acceptability are identified, state-of-development and FBC manufacturers are also noted. The problems with the Great Lakes FBC boiler plant were studied and possible remedial measures are given. Considerations for FBC retrofitting have been examined based on boiler size, age, configuration, accessory components, and available space. Recommendations on how to achieve the Navy's goal of coal utilization by the FBC approach are outlined.

  13. Partitioning behavior of trace elements during pilot-scale fluidized bed combustion of high ash content lignite.

    PubMed

    Selçuk, Nevin; Gogebakan, Yusuf; Gogebakan, Zuhal

    2006-10-11

    This study describes the partitioning of 20 trace elements (As, B, Ba, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, P, Pb, Sb, Se, Sn, Tl, V, Zn) and eight major and minor elements (Al, Ca, Fe, K, Mg, Na, Si, Ti) during the combustion of high ash content lignite. The experiments were carried out in the 0.3 MW(t) Middle East Technical University (METU) atmospheric bubbling fluidized bed combustor (ABFBC) test rig with and without limestone addition. Inert bed material utilized in the experiments was bed ash obtained previously from the combustion of the same lignite without limestone addition in the same test rig. Concentrations of trace elements in coal, limestone, bottom ash, cyclone ash and filter ash were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). Partitioning of major and minor elements are influenced by the ash split between the bottom ash and fly ash and that the major proportion of most of the trace elements (As, Ba, Cr, Hg, Li, Mo, Ni, Sn, V, Zn) are recovered in fly ash. Limestone addition shifts the partitioning of Ba, Cr, Mo, Ni, Sn, V, Zn from bottom ash to fly ash. PMID:16757112

  14. Trace elements partitioning during co-firing biomass with lignite in a pilot-scale fluidized bed combustor.

    PubMed

    Gogebakan, Zuhal; Selçuk, Nevin

    2009-03-15

    This study describes the partitioning of 18 trace elements (As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, P, Pb, Sb, Se, Sn, Tl, V, Zn) and 9 major and minor elements (Al, Ca, Fe, K, Mg, Na, S, Si, Ti) during co-firing of olive residue, hazelnut shell and cotton residue with high sulfur and ash content lignite in 0.3 MW(t) Middle East Technical University (METU) Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) test rig with limestone addition. Concentrations of trace elements in coal, biomass, limestone, bottom ash, cyclone ash and filter ash were determined by inductively coupled plasma optical emission and mass spectroscopy (ICP-OES and ICP-MS). Partitioning of major and minor elements are influenced by the ash split between the bottom ash and fly ash and that the major proportion of most of the trace elements (As, Ba, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Tl, V and Zn) are recovered in fly ash when firing lignite only. Co-firing lignite with biomass enhances partitioning of these elements to fly ash. Co-firing also shifts the partitioning of Cd, P, Sb and Sn from bottom to fly ash. PMID:18621479

  15. 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.

  16. Application of a fluidized bed combustor to the DARS process

    SciTech Connect

    Scott-Young, R.E.

    1995-12-31

    Australian Paper has built the world`s first and only operational Direct Alkali Recovery System (DARS) to recover caustic soda for a soda AQ chemical pulp mill. At the heart of the DARS process, concentrated spent pulping liquor is burnt in a fluidized bed. The bed material is made up of coarse, dense iron oxide pellets which require a high fluidizing velocity. Bubbling is violent and gives robust fluidization of the iron and sodium compounds. The plant suffered a protracted startup because of equipment failures, air flow instability problems, and process and equipment design errors. A large amount of post construction development work was required. This paper discusses the experiences and knowledge gained in adapting a fluidized bed to the DARS process.

  17. A three phase model of a batch fluidized bed

    NASA Astrophysics Data System (ADS)

    Aly, S. E.; Fathalah, K. A.

    A three phase mathematical model of simultaneous heat and mass transfer of a batch operation for a fluidized bed is presented. The three phases are a solid free bubble, emulsion and solid phases. The model employs an elaborate five equations porosity model. Various correlations for the minimum fluidization parameters are surveyed and compared with the adequate one is being adopted in the model. The governing equations together with the boundary and initial conditions are presented for a cyclic operation of the bed. These are numerically solved for a test case where the bed is charged with silica gel particles to dehumidify a process air stream. Thus the bed works in an air dehumidification mode/bed regeneration mode cyclic operation with matching conditions.Results for the bed operation are presented as the temperature and humidity ratio variations for the test case. The results indicate the ability of the developed model to provide the required data for the concerned batch operated fluidized bed.

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

    SciTech Connect

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

    2010-07-15

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

  19. 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

  20. Developing technologies for coal utilization

    NASA Astrophysics Data System (ADS)

    Penner, S. S.

    The utilization of coal slurries in place of oil in utility and industrial boilers; the development of improved atmospheric and pressurized fluidized bed combustors; the designs of integrated combined cycle systems; and coal gasification and liquefaction to augment supplies of natural gas and liquid fuels, respectively are discussed. The worldwide coal resource base is so large that the necessity to manufacture liquid fuels from coals must be realized. An initiative proposed by the International Energy Agency defines several specific direct coal liquefaction designs and sites where direct coal liquefaction may be implemented.

  1. 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

  2. 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.

  3. Lateral solids dispersion coefficient in large-scale fluidized beds

    SciTech Connect

    Liu, Daoyin; Chen, Xiaoping

    2010-11-15

    The design of fuel feed ports in a large-scale fluidized bed combustor depends on the fuel characteristics and lateral solids mixing. However, the reported values of the effective lateral solids dispersion coefficient (D{sub sr}) are scattered in the broad range of 0.0001-0.1 m{sup 2}/s. With the aim of predicting D{sub sr} in wider fluidized beds which is difficult to measure directly or deduce from experimental results in lab-scale facilities, a computational method is proposed. It combines the Eulerian-Granular simulation and fictitious particle tracing technique. The value of D{sub sr} is calculated based on the movement of the tracers. The effect on D{sub sr} of bed width (W) ranging from 0.4 m up to 12.8 m at different levels of superficial gas velocity (U{sub 0}) is investigated. It is found that increasing W whilst maintaining U{sub 0}, D{sub sr} initially increases markedly, then its increase rate declines, and finally it stays around a constant value. The computed values of D{sub sr} are examined quantitatively and compared with a thorough list of the measured D{sub sr} in the literature since 1980s. Agreed with the measurements performed in the pilot-scale fluidized beds, the value of D{sub sr} in wider facilities at higher fluidizing velocities is predicted to be around the order of magnitude of 0.1 m{sup 2}/s, much higher than that in lab-scale beds. Finally, the effect of D{sub sr} on the distribution of fuel particles over the cross section in fluidized beds with the specified layout of feed ports is discussed. (author)

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

    SciTech Connect

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

    1996-08-01

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

  5. 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.

  6. Fluidized bed combustion offers replacement option for old boilers

    SciTech Connect

    1997-01-01

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

  7. Fluidized bed gasification ash reduction and removal process

    DOEpatents

    Schenone, Carl E.; Rosinski, Joseph

    1984-12-04

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

  8. Bed drain cover assembly for a fluidized bed

    DOEpatents

    Comparato, Joseph R.; Jacobs, Martin

    1982-01-01

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

  9. 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.

  10. Design of fluidized-bed, biological denitrification systems

    SciTech Connect

    Patton, B.D.; Hancher, C.W.; Pitt, W.W.; Walker, J.F.

    1982-01-01

    Many commercial processes yield nitrate-containing wastewaters that are being discharged to the environment because traditional recovery or disposal methods are economically unacceptable. The anticipated discharge limits (i.e., 10 to 20 g (NO/sub 3//sup -/)/m/sup 3/) being considered by many states will not allow continued release of these wastewaters. The new discharge standards can be met economically by use of the fluidizied-bed, biological denitrification process. Research and development studies were conducted with 0.05-, 0.10-, 0.20-, and 0.50-m-diam fluidized-bed bioreactor systems. Feed nitrate concentrations were in the 0 to 10,000 g (NO/sub 3//sup -/)/m/sup 3/ range. Using the data from these studies, rate expressions were developed for the destruction of nitrate as a function of nitrate concentration. Methods were also developed for sizing bioreactors and biomass control systems. The sizing methods for fluidized-bed denitrification systems are described, and support systems such as sampling and analysis, instrumentation and controls, utilities, and bacteria storage are discussed. Operation of the process is also briefly discussed to aid the designer. Using the methods presented in this report, fluidized-bed, biological denitrification systems can be designed to treat nitrate wastewater streams.

  11. 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.

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

    SciTech Connect

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

    1987-10-01

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

  13. 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.

  14. 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.

  15. Staged fluidized-bed combustion and filter system

    DOEpatents

    Mei, Joseph S.; Halow, John S.

    1994-01-01

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

  16. 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.

  17. Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1993--March 31, 1993

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.D.

    1993-04-01

    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 and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed boilers is in progress. Preliminary results indicate that at least five boilers were experiencing some form of bed material agglomeration. In these instances it was observed that large particles were forming within the bed which were larger that the feed. Four operators could confirm that the larger bed particles had formed due to bed particles sticking together or agglomerating. Deposit formation was reported at nine sites with these deposits being found most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Examples of these agglomerates and deposits have been received from five of the surveyed facilities. Also during this quarter, a bulk sample of Illinois No. 6 coal was obtained from the Fossil Energy Program at Ames Laboratory here at Iowa State University and prepared for combustion tests. This sample was first ground to a top-size of 3/8`` using a jaw crusher then a size fraction of 3/8`` {times} 8 (US mesh) was then obtained by sieving using a Gilson Test-Master. This size fraction was selected for the preliminary laboratory-scale experiments designed to simulate the dense bed conditions that exist in the bottom of CFB combustors. To ensure uniformity of fuel composition among combustion runs, the sized coal was riffled using, a cone and long row method and stored in bags for each experiment. During this quarter additional modifications were made to achieve better control of fluidization regimes and to aid in monitoring the hydrodynamic and chemical conditions within the reactor.

  18. 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.

  19. Dioxins and their fingerprint in size-classified fly ash fractions from municipal solid waste incinerators in China--mechanical grate and fluidized bed units.

    PubMed

    Lu, Sheng-Yong; Du, Yingzhe; Yan, Jian-Hua; Li, Xiao-Dong; Ni, Ming-Jiang; Cen, Ke-Fa

    2012-06-01

    The distribution of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), in brief dioxins, has seldom been addressed systematically in fly ash from municipal solid waste incinerators (MSWIs). This study shows the amount and fingerprint of PCDD/Fs in fly ash from four different Chinese MSWIs, that is, three mechanical grate units and one circulating fluidized bed unit. In these fly ash samples, dioxins-related parameters (international toxic equivalent quantity, total amount of PCDD/Fs, individual isomer classes, and 17 toxic 2,3,7,8-substituted congeners) all tend to increase with decreasing particle size for mechanical grate incinerators, yet only for the finest fraction for fluidized bed units. Moreover, the fluidized bed incinerator seems superior to grate incineration in controlling dioxins, yet a comparison is hampered by internal differences in the sample, for example, the fluidized bed fly ash has much lower carbon and chlorine contents. In addition, the presence of sulfur from mixing coal as supplemental fuel to the MSW may poison the catalytic steps in dioxins formation and thus suppress the formation of dioxins. With more residual carbon and chlorine in the fly ash, it is easier to form dioxins during cooling. Nevertheless, there is no apparent relation between Fe, Cu, and Zn contents and that of dioxins in fly ash. PMID:22788110

  20. 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.

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

    SciTech Connect

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

    2015-02-24

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

  2. 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.

  3. 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.

  4. Effects of applied sewage sludge compost and fluidized bed material on apple seedling growth

    SciTech Connect

    Korcak, R.F.

    1980-01-01

    Two waste products, composted sewage sludge and fluidized bed material (FBM, a coal/limestone combustion byproduct) were used as soil amendments for apple seedlings (Malus domestica) grown in the greenhouse. Compost was applied at rates equivalent to 0, 25 and 50 dry metric tons/ha and FBM was applied at levels of 1 and 2 times the soil lime requirement on a weight basis (12.5 and 25.0 metric tons/ha). Plant growth was significantly increased by compost or FBM additions. Tissue Ca was increased by both waste, reflecting the high Ca inputs to the low fertility Arendtsville soil. Potentially high soil Mn levels were reduced by both wastes due to their neutralizing effect on soil pH. Root Cd levels were increased by compost additions even though soil pH was maintained above 6.3. Tissue Zn, Cu and Ni were not consistently affected by waste additions.

  5. Prediction of Co-Firing Characteristics of Wastes in Circulating Fluidized Bed by Fuel Properties

    NASA Astrophysics Data System (ADS)

    Murakami, Takahiro; Suda, Toshiyuki

    The purpose of this study is to experimentally investigate the co-firing characteristics of different kinds of wastes in circulating fluidized bed combustors, and further to correlate the acquired combustion efficiency with fuel property parameters. The tested individual fuels were wasted tire, RPF, wood tip, RDF and coal, which typified the fuels with distinctively different contents of volatile matters. Coal was employed to represent the fuel containing particularly low volatile matters. The experiments were carried out in a pilot circulating fluidized bed combustor, and varied parameters included the fuel blending ratio, furnace temperature and secondary air ratio. The acquired results indicated that co-firing wasted tire and RPF led to higher CO concentration in the flue gas than firing RPF independently, and this CO concentration increased with increasing the blending ratio of wasted tire. The lower volatile matter content, higher carbon to hydrogen ratio (C⁄H ratio) and carbon to oxygen ratio (C⁄O ratio) of wasted tire than those of RPF were suggested to be responsible for the results. The study also found that the available combustion efficiencies in co-firing various pairs of the tested fuels were correlative with the volatile matter contents, C⁄H and C⁄O ratios of the blended fuels estimated as the weighed sums of the same property parameters of individual fuels. This allows thus a simple determination of the co-firing efficiency of any fuel blend from calculating the blend‧s fuel property parameters using the fuel blending ratio as a weight.

  6. 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...

  7. 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.

  8. 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.

  9. CFD Analysis of Bubbling Fluidized Bed Using Rice Husk

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

    Robertson, A.; Bonk, D.

    1994-04-01

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

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

    SciTech Connect

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

    1986-02-01

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

  12. Evaluation of vibrated fluidized bed techniques in coating hemosorbents.

    PubMed

    Morley, D B

    1991-06-01

    A coating technique employing a vibrated fluidized bed was used to apply an ultrathin (2 microns) cellulose nitrate coating to synthetic bead activated charcoal. In vitro characteristics of the resulting coated sorbent, including permeability to model small and middle molecules, and mechanical integrity, were evaluated to determine the suitability of the process in coating granular sorbents used in hemoperfusion. Initial tests suggest the VFB-applied CN coating is both highly uniform and tightly adherent and warrants further investigation as a hemosorbent coating. PMID:1885246

  13. Feasibility of rotating fluidized bed reactor for rocket propulsion

    NASA Technical Reports Server (NTRS)

    Ludewig, H.; Manning, A. J.; Raseman, C. J.

    1974-01-01

    The rotating fluidized bed reactor concept is outlined, and its application to rocket propulsion is discussed. Experimental results obtained indicate that minimum fluidization correlations commonly in use for 1-g beds can also be applied to multiple-g beds. It was found that for a low thrust system (20,000 lbf) the fuel particle size and/or particle stress play a limiting role on performance. The superiority of U-233 as a fuel for this type of rocket engine is clearly demonstrated in the analysis. The maximum thrust/weight ratio for a 90,000N thrust engine was found to be approximately 65N/kg.

  14. Fluidized-bed deactivation model of a methanation system

    SciTech Connect

    Willey, R.J.; Kittrell, J.R.

    1984-06-01

    Fluidized-bed data on the deactivation of a Ni-Mo-Cu on an alumina methanation catalyst is best described by a pseudo-steady-state continuous-stirred tank reactor model for a deactivation rate that is proportional to the catalyst activity and CO concentration. However, to treat the full range of available data, researchers had to combine an active site balance with a CO balance to account for the variation of CO concentration with time-on-stream due to catalyst deactivation.

  15. Steady State Sedimentation in a Liquid Fluidized Bed

    NASA Technical Reports Server (NTRS)

    Segre, P. N.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    The velocity fluctuations and the local particle concentration of a particle suspension exhibiting steady state sedimentation in a fluidized bed are determined as a function of height along the particle column. Both the velocity fluctuations and the particle volume fraction are found to strongly depend on height. We account for the stability of the bed by a simple model evoking a flux balance. Velocity fluctuations driving a downward particle flux are compensated by an upward particle flux stemming from an excess flow velocity due to the concentration gradient of the system.

  16. Experimental evaluation and modeling of agglomerating fine powder fluidized beds

    SciTech Connect

    Yadav, N.K.; Kulkarni, B.D. ); Doraiswamy, L.K. . Dept. of Chemical Engineering)

    1994-10-01

    The effects of fines on the behavior of a fluidized-bed reactor have been investigated using a commercial catalyst for propylene ammoxidation. Experimental studies show that the catalyst powder agglomerates and that there exists a critical level of fines in the bed (around 30%) for which the fluid-bed behavior in terms of bed expansion, aeratability, and cluster size is optimum. The results also suggest that the dense phase should indeed be treated as two distinct phases: cluster and emulsion. A general mathematical model to account for these two phases is proposed.

  17. Fluidized bed incineration process design for transuranic waste

    SciTech Connect

    Johnson, A. J.; Meyer, F. G.; Anderson, D. L.; Bell, B. A.; Feng, P. K.

    1980-07-19

    A fluidized bed incineration facility has been installed at the Rocky Flats Plant to develop and demonstrate a process for the combustion of transuranic waste. The unit's capacity is about 82 kg/hr of combustible solid waste, which is nine times higher than the rate for the operating pilot-scale unit. The facility utilizes nonaqueous, in situ neutralization of acid gases. These gases are generated during the combustion of halogen-containing materials. The low-temperature (550 /sup 0/C) operation eliminates refractory-lined equipment.

  18. 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.

  19. Standby cooling system for a fluidized bed boiler

    DOEpatents

    Crispin, Larry G.; Weitzel, Paul S.

    1990-01-01

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

  20. Engineer, design, construct, test and evaluate a pressurized fluidized bed pilot plant using high sulfur coal for production of electric power: Phase III. Pilot plant construction. Quarterly report, September 1-November 30, 1980

    SciTech Connect

    Not Available

    1980-01-01

    Technical progress during the period September 1-November 30, 1980 on DOE Contract DE-AC21-76ET10417 is described. The design of the material handling equipment by the various vendors continues on schedule. Coal and dolomite feed system procurement was initiated. The SWEC Field Construction Office was established and site mobilization of the contractor for Bid Package No. 1 (Substructure) was initiated. Purchase orders were placed for the fabrication of all the PFB process recycle loop components. All preparatory work for placement of Bid Package No. 2, Structural Steel Erection, has been completed. Contract funding limitations have prevented placement of this purchase order.

  1. Modeling of the process of burning-out of coke-ash particles in a fluidized bed

    NASA Astrophysics Data System (ADS)

    Rokhman, B. B.

    2012-05-01

    A generalized statistical model of the process of burning out of coal particles in a fluidized-bed furnace is constructed. It takes into account the kinetics of heterogeneous chemical reactions, as well as radiant and convective-conductive heat transfer, which made it possible to considerably expand the region of application of the existing models. Different schemes of the behavior of ash in the process of burning of carbon particles are considered. Boundary conditions (conditions of matching) were formulated, and analytical solutions for the distribution function of particles in small intervals of carbon concentration for surface and bulk reaction have been obtained.

  2. 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

  3. Fluidized-bed combustion and gasification of biomass

    SciTech Connect

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

    1981-01-01

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

  4. 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.

  5. Functionalizing titania nanoparticle surfaces in a fluidized bed plasma reactor

    NASA Astrophysics Data System (ADS)

    Deb, B.; Kumar, V.; Druffel, T. L.; Sunkara, M. K.

    2009-11-01

    Functionalizing nanoparticle surfaces is essential for achieving homogeneous dispersions of monodisperse particles in polymer nanocomposites for successful utilization in engineering applications. Functionalization reduces the surface energy of the nanoparticles, thereby limiting the tendency to agglomerate. Moreover, reactive groups on the surface can also participate in the polymerization, creating covalent bonds between the inorganic and organic phases. In this paper, a fluidized bed inductively coupled plasma (FB-ICP) reactor is used to break apart the agglomerates and functionalize commercial TiO2 nanoparticle powders in a batch of several grams. The fluidized bed could be implemented into a continuous flow reactor, potentially making this a viable method to treat larger quantities of commercial powders. The particles are treated with acrylic acid (AA) and tetraethylorthosilicate (TEOS) plasma and the functionalized particles were collected separately from bulk powder. High resolution transmission electron microscopy (HRTEM) analysis showed that the particles were coated uniformly with polymer coatings with thicknesses around a few nanometers. Fourier-transformed infrared spectroscopy (FTIR) studies of the polymer-coated particles showed the presence of different functional groups (poly-acrylic acid/siloxane) similar to that present in the bulk films. The dispersion behavior of the TiO2 nanoparticles showed much improvement with reduced agglomerate size.

  6. Microwave fluidized-bed detoxification of hazardous waste

    SciTech Connect

    Varma, R.

    1991-11-01

    Our ongoing research and development (R D) work focuses on demonstrating the technical feasibility of total detoxification of C1HC'' hazardous waste by using microwave energy. In addition, we investigated the capability of nahacolite for in-bed scavenging of HC1 and found it to be very effective. So far, detoxification of halocarbon vapor and liquid waste forms has been achieved. Microwave energy heats and activates the particulates of silicon carbide (SiC) and promotes chemical interactions, facilitating total detoxification of chlorinated hydrocarbons (TCEs) in an air-stream over SiC-fluidized beds under mild (<600{degrees}) conditions. The SiC promotes surface-enhanced reactions and also is a heating transfer medium. These microwave-assisted processes appear to be extremely energy efficient. The Los Alamos National Laboratory (LANL) team can demonstrate the microwave fluidized bed (MFB) technology for total detoxification of halocarbon waste streams. The technology is applicable for treatment of hazardous waste at DOE sites. 5 refs., 5 figs.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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

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

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Use of fluidized bed combustion not feasible-general... FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion not... finds on a site-specific or generic basis that use of a method of fluidized bed combustion of...

  13. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Use of fluidized bed combustion not feasible-general... FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion not... finds on a site-specific or generic basis that use of a method of fluidized bed combustion of...

  14. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Use of fluidized bed combustion not feasible-general... FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion not... finds on a site-specific or generic basis that use of a method of fluidized bed combustion of...

  15. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Use of fluidized bed combustion not feasible-general... FUELS NEW FACILITIES General Requirements for Exemptions § 503.10 Use of fluidized bed combustion not... finds on a site-specific or generic basis that use of a method of fluidized bed combustion of...

  16. 10 CFR 503.10 - Use of fluidized bed combustion not feasible-general requirement for permanent exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  17. 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).

  18. Temperatures in a fuel particle burning in a fluidized bed: The effect of drying, devolatilization, and char combustion

    SciTech Connect

    Winter, F.; Prah, M.E.; Hofbauer, H.

    1997-02-01

    Intra-particle temperatures and the emissions of carbon dioxide, carbon monoxide, and total hydrocarbons have been measured during devolatilization and char combustion of large spheres (3--20 mm diameter) of selected fuels. The fuels range from a carbon-rich, bituminous coal to two different, sub-bituminous coals of very different moisture and ash contents, to a highly volatile and ash-rich sewage sludge and to beech wood with the highest volatile content. To obtain results under various fluidized bed combustor conditions and to independently change the governing parameters, the experiments were performed in three different laboratory-scale fluidized bed combustors (FBCs). The beds` temperatures varied between 700 and 950 C, the oxygen partial pressure in the fluidizing gas varied from 0 to 21 kPa, the superficial gas velocity from 0.3 to 9 m/s, the voidage of the fluidized particles in the beds was usually 0.5 or 0.997, and the mean diameter of the fluidized particles was 200 or 900 {micro}m. A dynamic simulation model has been developed to describe the behavior of a single fuel particle during its lifetime in a combustor. The model considers drying, devolatilization, volatile and char combustion, external and internal heat and mass transfer, and changing fuel properties. Calculated temperature profiles and emission data are in good agreement with observations.

  19. Fluidized bed combustor test report for Proof-of-Concept Oil Shale Facility, Colorado Tract C-b

    SciTech Connect

    Moore, R.E.; Vawter, R.G.; Yerushalmi, J.

    1990-11-01

    During 1990 Occidental Oil Shale, Inc. prepared a Plan and Justification for the Department of Energy for a Proof-of-Concept Oil Shale Facility on Colorado Tract C-b. The subject facility is designed to produce shale oil from the Modified Insitu (MIS) process and electric power from the burning of indigenous fuels. One of the tasks included in the program is Fluidized Bed Combustor Design Parameter Confirmation. This report summarizes the work conducted for that task. Two pilot plant tests were conducted on a combination of oil shale, simulated gas from the MIS process and coal; at facilities owned and operated by manufacturers of circulating fluidized bed combustors (CFBC). In addition air emission testing was conducted during the two pilot plant tests and on the residue ash produced from the pilot plants. Based on the results of the tests, it has been concluded that combinations of oil shale, coal and MIS gas can be efficiently combusted in a demonstration scale CFBC in an environmentally acceptable manner. The tests also confirmed that Western US oil shale is a very effective SO{sub 2} removal agent. Three appendices contain the reports provided by the contractors that conducted the principal tests. These reports were processed separately for inclusion on the data base.

  20. Pressurized fluidized-bed hydroretorting of eastern oil shales

    SciTech Connect

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

    1991-12-01

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