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1

Atmospheric fluidized-bed combustion coal feeding test program  

Microsoft Academic Search

Development of a coal feeding and distribution system is one of the major requirements for successful operation of large scale atmospheric fluidized-bed boilers. Since combustion efficiency, sulfur capture, and tube corrosion are strong functions of coal distribution in the bed, the reliability of the feed system is critical. One proposed coal feeding method involves underbed feed nozzles, and pneumatic conveying

C. S. Daw; J. F. Thomas; R. S. Holcomb; C. K. Andrews

1980-01-01

2

Catalytic coal partial gasification in an atmospheric fluidized bed  

Microsoft Academic Search

The coal partial gasification catalyzed by limestone, sodium carbonate and dolomite was studied using a bench-scale atmospheric\\u000a fluidized bed in the presence of air and steam at 900 °C. The effects of limestone, sodium carbonate and dolomite on composition,\\u000a heating value, gas yield of product gas and carbon conversion in the catalytic coal partial gasification have been examined.\\u000a The experimental

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

2007-01-01

3

Pulsed atmospheric fluidized bed combustion  

SciTech Connect

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.

Not Available

1992-08-01

4

Fluidized bed coal desulfurization  

NASA Technical Reports Server (NTRS)

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.

Ravindram, M.

1983-01-01

5

Pulsed atmospheric fluidized bed combustion  

SciTech Connect

The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.

Not Available

1992-10-01

6

Pulsed atmospheric fluidized bed combustion  

SciTech Connect

The Design and Engineering of most components in the Pulsed Atmospheric Fluidized Bed System was completed prior to September 1992. The components remaining to be designed at that time were: Aerovalves for the Pulse Combustor; Gas and coal injectors for the Pulse Combustor; Lines for PC tailpipes; Air plenum and inlet silencer; Refractory lined hot gas duct connecting outlet hot cyclone to boiler; Structure and platforms, and ladders around PAFBC vessel access and major equipment. Design work is currently in progress on all of the above components. Items 1, 2, 3 and 4 are 50% completed, and items 5 6 are 75% complete.

Not Available

1993-01-01

7

The atmospheric bubbling fluidized bed combustion of coal in the Netherlands, cleaner it can't be  

Microsoft Academic Search

The use of coal in atmospheric bubbling fluidized bed combustors for the generation of process steam is still a viable option for industrial applications world wide but interest in this as and electricity generation technology has also grown. The general advantages of AB-FBC are environmental acceptability and great fuel flexibility. As will be shown in this paper, it has a

van Gasselt

1991-01-01

8

Pulsed atmospheric fluidized bed combustion  

SciTech Connect

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.

Not Available

1989-11-01

9

Pulsed atmospheric fluidized bed combustion  

SciTech Connect

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.

Not Available

1992-05-01

10

Coal-Fired Fluidized Bed Combustion Cogeneration  

E-print Network

COAL-FIRED FLUIDIZED BED COMBUSTION COGENERATION Cabot Thunem, P.E Norm Smith, P.E. Stanley Consultants, Inc. Muscatine, Iowa ABSTRACT The availability of an environmentally accep table multifuel technology, such as fluidized bed..., this addition of cogeneration to the fuel conver sion analysis considerably complicates the investi gation. A system design for cogeneration of steam and electricity at a nominal 40,000 pound per hour capacity utilizing fluidized bed combustion...

Thunem, C.; Smith, N.

11

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

SciTech Connect

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.

Not Available

1993-02-01

12

Fluidized bed coal combustion reactor  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

13

Design of the atmospheric fluidized-bed coal combustor for cogeneration gas-turbine system  

SciTech Connect

The AFB Coal Combustor for Cogeneration Program, sponsored by the US Department of Energy, has as its objective the development of the technology for a fluidized bed coal combustion system to provide a source of high-temperature air for power generation with gas turbines and for process heating in industrial plants. The program is directed toward systems in the size range of 5 to 50 MW(e) and is being conducted by the Oak Ridge National Laboratory and its subcontractors. The major effort in the program is the design of a generic reference plant cogeneration system and the design and construction of a test system that will incorporate the salient features of the reference plant. The design work was initiated in June 1980.

Holcomb, R.S.; Berman, P.A.; Gorrell, R.L.

1981-01-01

14

Fluidized bed selective pyrolysis of coal  

DOEpatents

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.

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

1992-12-15

15

Fluidized bed selective pyrolysis of coal  

DOEpatents

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.

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

1992-01-01

16

Fluidized bed catalytic coal gasification process  

DOEpatents

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.

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

17

Fluidized bed catalytic coal gasification process  

Microsoft Academic Search

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

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

1984-01-01

18

Fluidized bed catalytic coal gasification process  

Microsoft Academic Search

Coal or similar carbonaceous solids impregnated with gasification catalyst constituents are oxidized by contact with a gas containing between 2 volume percent and 21 volume percent oxygen at a temperature between 50° C. and 250° 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.

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

1984-01-01

19

The atmospheric bubbling fluidized bed combustion of coal in the Netherlands, cleaner it can't be  

SciTech Connect

The use of coal in atmospheric bubbling fluidized bed combustors for the generation of process steam is still a viable option for industrial applications world wide but interest in this as and electricity generation technology has also grown. The general advantages of AB-FBC are environmental acceptability and great fuel flexibility. As will be shown in this paper, it has a great potential for meeting possible future, even more stringent, regulations. Since 1979, Stork Boilers, TNO and Twente University have been carrying out a joint national research programme aimed at the design of industrial installations operating to stringent emission standards. This has led to the demonstration of a 90 MWth industrial boiler at the AKZO Chemical Works. The work has been under the control of NOVEM, the Netherlands Agency of Energy and the Environment. This body provides the financial resources on behalf of the Dutch Ministry of Economic Affairs by awarding annual contracts.

van Gasselt, M.L.G. (TNO-Apeldoorn, P.O. Box 342,7300 AH Apeldoorn (NL))

1991-01-01

20

Gas distributor for fluidized bed coal gasifier  

DOEpatents

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.

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

1980-01-01

21

Nucla circulating atmospheric fluidized bed demonstration project  

SciTech Connect

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.

Not Available

1991-10-01

22

Pulsed atmospheric fluidized bed combustion. Final report  

SciTech Connect

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.

Not Available

1989-11-01

23

Fluidized bed gasification of extracted coal  

DOEpatents

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.

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

1984-07-06

24

Fluidized bed gasification of extracted coal  

DOEpatents

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.

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

1986-01-01

25

Fluidized bed injection assembly for coal gasification  

DOEpatents

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.

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

1981-01-01

26

Atmospheric fluidized bed cogeneration generic studies and air heater experiment  

SciTech Connect

This executive summary, final report, presents the results of the Department of Energy-sponsored program to evaluate a cogeneration system which integrated an indirectly heated open cycle gas turbine with an atmospheric fluidized bed fired with coal. This concept uses combinations of steam and 1500{degree}F (816{degree}C) pressurized air to generate electricity, process air and process steam. Nine cogeneration systems, based on the bubbling, circulating and supercharged fluidized bed air heater concepts were conceptually designed, priced and evaluated. Westinghouse concluded that the economics of the cogeneration systems were very sensitive to the life of the in-bed heat exchanger. After giving an overview of the advanced fluidized bed air heater technology program, this report reviews the results of testing various air heater candidate materials for up to 2000 hours in a 6-ft x 6-ft (1.8 m {times} 1.8 m) bubbling atmospheric fluidized bed test facility. Two platens which had previously been used in the bed had an additional 1000 hours of exposure making a total of 3000 hours. Results of these tests were used to quantify material corrosion rates. Tube life predictions were made by each boiler manufacturer based upon their metallurgical examinations. For tubing alloys (with and without cladding), weldments and filler material, and supports and clamps, several materials were selected which should have a 10-year life expectancy when used under the fluidized bed operating conditions achieved in this study. The fluidized bed air heater cycle offers the potential for a low-cost, uncomplicated method of burning high-sulfur-bearing coal in an environmentally acceptable manner.

Bannister, R.L.; Whitlow, G.A. (Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center)

1991-07-01

27

Atmospheric fluidized bed combustion advanced concept system  

SciTech Connect

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.

Not Available

1992-05-01

28

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

SciTech Connect

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.

Not Available

1992-08-01

29

NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project  

SciTech Connect

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)

Not Available

1992-02-01

30

Simulation of fluidized bed coal combustors  

NASA Technical Reports Server (NTRS)

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.

Rajan, R.

1979-01-01

31

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

SciTech Connect

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

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

1980-10-01

32

Atmospheric fluidized bed cogeneration generic studies and air heater experiment  

Microsoft Academic Search

This executive summary, final report, presents the results of the Department of Energy-sponsored program to evaluate a cogeneration system which integrated an indirectly heated open cycle gas turbine with an atmospheric fluidized bed fired with coal. This concept uses combinations of steam and 1500°F (816°C) pressurized air to generate electricity, process air and process steam. Nine cogeneration systems, based on

R. L. Bannister; G. A. Whitlow

1991-01-01

33

International energy technology assessment: Atmospheric fluidized-bed combustion  

NASA Astrophysics Data System (ADS)

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.

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

1982-04-01

34

Pulsed atmospheric fluidized-bed combustor development. Environmental Assessment  

SciTech Connect

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.

Not Available

1992-05-01

35

Pulsed atmospheric fluidized bed combustion. Final report  

SciTech Connect

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.

NONE

1998-03-01

36

Destruction of Tar During Oxidative and Nonoxidative Pyrolysis of Bituminous Coal in a Fluidized Bed  

Microsoft Academic Search

The yields of tar on devolatilization of bituminous coal were measured in a small scale fluidized bed reactor, under conditions pertinent to large scale bubbling atmospheric pressure fluidized bed combustors(AFBC). The tar was collected by cooling the entire product stream from the reactor using a water-cooled quartz tube, followed by a filter for particulate matter, and a polystyrene sorbent (XAD-2)

HÜSEYÍN VURAL; PETER M. WALSH; ADEL F. SAROFIM; J?NOS M. BEÉR

1989-01-01

37

Development and applications of clean coal fluidized bed technology  

SciTech Connect

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.

Eskin, N.; Hepbasli, A. [Ege University, Izmir (Turkey). Faculty of Engineering

2006-09-15

38

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...

39

Development and Applications of Clean Coal Fluidized Bed Technology  

Microsoft Academic Search

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

Nurdil Eskin; Arif Hepbasli

2006-01-01

40

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...

41

Mathematical modelling of coal fired fluidized bed combustors  

Microsoft Academic Search

A system model of continuous fluidized bed combustors burning coal of wide size distribution has been derived, and applied to the investigation of the effect of excess air and recycle on bed concentration and temperature profiles and combustion efficiency of a pilot scale coal fired fluidized combustor. To demonstrate the effect of recycling, the behaviour of the fluidized combustor has

N. Selcuk; R. G. Siddall; U. Sivrioglu

1980-01-01

42

Fluidized bed combustor and coal gun-tube assembly therefor  

DOEpatents

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.

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

1984-01-01

43

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...

44

Experimental study on coal multi-generation in dual fluidized beds  

NASA Astrophysics Data System (ADS)

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

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

2007-08-01

45

Inclined fluidized bed system for drying fine coal  

DOEpatents

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.

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

1992-02-11

46

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

Microsoft Academic Search

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

Thimsen

1991-01-01

47

Fluidized-bed combustion reduces atmospheric pollutants  

NASA Technical Reports Server (NTRS)

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.

Jonke, A. A.

1972-01-01

48

Method for using fast fluidized bed dry bottom coal gasification  

DOEpatents

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.

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

1983-01-01

49

Nucla circulating atmospheric fluidized bed demonstration project. Final report  

SciTech Connect

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.

Not Available

1991-10-01

50

Fluidized-bed bioreactor process for the microbial solubiliztion of coal  

DOEpatents

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.

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

1989-01-01

51

Fluidized-bed bioreactor system for the microbial solubilization of coal  

DOEpatents

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.

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

1987-09-14

52

Coal-fired CAES system using fluidized bed combustion  

SciTech Connect

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.

Moskowitz, S.; Schaeffer, R.

1983-11-01

53

Nucla circulating atmospheric fluidized bed demonstration project  

SciTech Connect

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.

Not Available

1991-01-31

54

Ash Vaporization in Circulating Fluidized Bed Coal Combustion  

Microsoft Academic Search

In this work, the vaporization of the ash forming constituents in circulating fluidized bed combustion (CFBC) in a full-scale 80 MWth unit was studied. Ash vaporization in CFBC was studied by measuring the fly ash aerosols in a full-scale boiler upstream of the electrostatic precipitator (ESP) at the flue gas temperature of 125°C. The fuel was a Venezuelan bituminous coal,

Terttaliisa Lind; Esko I. Kauppinen; Willy Maenhaut; Anup Shah; Frank Huggins

1996-01-01

55

Clean coal fluidized-bed technology in Poland  

Microsoft Academic Search

The use of a circulating fluidized-bed (CFB) for power generation is a rapidly growing technology in Poland. The ability of CFBs to burn a wide variety of fuels, while meeting strict emission-control regulations, makes them an ideal choice for burning such fuels as high-sulfur coal, lignite, peat, oil, sludge, petroleum coke, gas and wastes. All these fuels are burned cleanly

W. Nowak

2003-01-01

56

Benzo(a)pyrene, benzo(a)anthracene, and dibenzo(a,h)anthracene emissions from coal and waste tire energy generation at atmospheric fluidized bed combustion (AFBC).  

PubMed

The main aim of this work was the analyzing of the release to the atmosphere of benzo[a]pyrene (BaP), dibenzo(a,h)anthracene (D(a,h)A), and benzo[a]anthracene (BaA), three of the most carcinogenic PAHs listed by US-EPA as priority pollutants, emitted from combustion at the last generation reactors used nowadays in power generation, fluidized bed reactors, trying to establish their incidence when waste materials are used as "new fuels". BaP, D(a,h)A, and BaA emissions, once collected in the sampling system, have been analyzed by fluorescence spectroscopy in the synchronous mode (FS) after extraction by ultrasonic bath with dimethylformamide (DMF) as solvent. Concerning to the combustion variables influence, the conclusion reached was that, in coal combustion, the lowest emissions of BaP are generated at percentages of excess oxygen of 20%, at flows corresponding to good fluidization conditions, 860 L/h (double of the minimum fluidization velocity) and temperatures out of 850 degrees C; the lowest emission of D(a,h)A are emitted at 20% excess oxygen, 900 L/h and out of 750 degrees C, and the lowest emission of BaA are generated at 20% excess oxygen, 860 L/h and out of the range 750-850 degrees C. Regarding tire as nonfossil fuel, higher emissions of BaP, BaA, and D(a,h)A are detected in comparison to coal combustion. In coal-tire blend, the BaP, BaA, and D(a,h)A emissions are more similar to the values obtained in coal combustion and not intermediate values as it could be expected by the blend composition. PMID:11452587

Mastral, A M; Callén, M S; García, T; Lopez, J M

2001-07-01

57

METHOD FOR ANALYZING EMISSIONS FROM ATMOSPHERIC FLUIDIZED-BED COMBUSTOR  

EPA Science Inventory

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

58

Atmospheric fluidized bed cogeneration generic studies and air heater experiment. Final report, Executive summary  

SciTech Connect

This executive summary, final report, presents the results of the Department of Energy-sponsored program to evaluate a cogeneration system which integrated an indirectly heated open cycle gas turbine with an atmospheric fluidized bed fired with coal. This concept uses combinations of steam and 1500{degree}F (816{degree}C) pressurized air to generate electricity, process air and process steam. Nine cogeneration systems, based on the bubbling, circulating and supercharged fluidized bed air heater concepts were conceptually designed, priced and evaluated. Westinghouse concluded that the economics of the cogeneration systems were very sensitive to the life of the in-bed heat exchanger. After giving an overview of the advanced fluidized bed air heater technology program, this report reviews the results of testing various air heater candidate materials for up to 2000 hours in a 6-ft x 6-ft (1.8 m {times} 1.8 m) bubbling atmospheric fluidized bed test facility. Two platens which had previously been used in the bed had an additional 1000 hours of exposure making a total of 3000 hours. Results of these tests were used to quantify material corrosion rates. Tube life predictions were made by each boiler manufacturer based upon their metallurgical examinations. For tubing alloys (with and without cladding), weldments and filler material, and supports and clamps, several materials were selected which should have a 10-year life expectancy when used under the fluidized bed operating conditions achieved in this study. The fluidized bed air heater cycle offers the potential for a low-cost, uncomplicated method of burning high-sulfur-bearing coal in an environmentally acceptable manner.

Bannister, R.L.; Whitlow, G.A. [Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center

1991-07-01

59

Atmospheric fluidized bed combustion advanced concept system. Final report  

SciTech Connect

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.

Not Available

1992-05-01

60

Characterization of particulate matter in the hot product gas from atmospheric fluidized bed biomass gasifiers  

Microsoft Academic Search

This study compares the characteristics of particulate matter (PM) in the hot product gas from three different atmospheric fluidized bed biomass gasifiers: a bubbling fluidized bed (BFB) gasifier, a circulating fluidized bed (CFB) gasifier, and an indirect BFB gasifier (the latter integrated with a CFB boiler). All gasifiers displayed a bimodal particle mass size distribution with a fine mode in

Eva Gustafsson; Leteng Lin; Michael Strand

2011-01-01

61

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

SciTech Connect

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

Not Available

1989-05-01

62

Desulfurization in reducing atmosphere and ammonia injection denitrification in a coal-fired fluidized bed combustor with fly-ash recycle  

NASA Astrophysics Data System (ADS)

With the rising of IGCC and the second generation PFBC-CC, and with the development of technology of staged combustion to lower emission of NOx, the desulfurization efficiency under reducing atmosphere is raised. In this paper, with the application of the fly-ash recycle and two-stage combustion technologies in a fluidized bed combustor, the desulfurization test under reducing atmosphere is described. Meanwhile, ammonia injection test was also conducted. Results show that desulfurization under reducing atmosphere has higher efficiency, and ammonia injection denitrification effect is very perfect.

Zhong, Zhaoping; Lan, Jixiang; Han, Yongsheng; Wu, Xin; Zheng, Haiyun

1997-03-01

63

NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project. 1990 Annual report  

SciTech Connect

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)

Not Available

1992-02-01

64

Desulfurization of Coal in Fluidized Beds  

NASA Technical Reports Server (NTRS)

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.

Maddury, R.; Kalvinskas, J.

1985-01-01

65

Characterization of fuels for atmospheric fluidized bed combustion  

SciTech Connect

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

Daw, C.S. (Oak Ridge National Lab., TN (USA)); Rowley, D.R.; Perna, M.A. (Babcock and Wilcox Co., Alliance, OH (USA). Research Center); Stallings, J.W. (Electric Power Research Inst., Palo Alto, CA (USA)); Divilio, R.J. (Combustion Systems, Inc., Silver Spring, MD (USA))

1990-01-01

66

Pulsed atmospheric fluidized bed combustion. Quarterly technical progress report, July 1992--September 1992  

SciTech Connect

The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.

Not Available

1992-10-01

67

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

SciTech Connect

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.

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

1999-09-01

68

Atmospheric fluidized bed cogeneration generic studies and air heater experiment. Final report, Executive summary  

Microsoft Academic Search

This executive summary, final report, presents the results of the Department of Energy-sponsored program to evaluate a cogeneration system which integrated an indirectly heated open cycle gas turbine with an atmospheric fluidized bed fired with coal. This concept uses combinations of steam and 1500°F (816°C) pressurized air to generate electricity, process air and process steam. Nine cogeneration systems, based on

R. L. Bannister; G. A. Whitlow

1991-01-01

69

Particulate control experience after fluidized bed boilers firing coal  

SciTech Connect

The energy crisis resulted in an intensified development of the fluidized bed boiler. In 1983, ten years later there are in the western world more than 100 units in operation or under construction. Manufacturers can offer designs with slow (bubbling) or fast (circulating) beds supported by more or less extensive experience. The fluidized bed combustor (FBC) has many advantages claimed or proven over ''older'' coal combustion methods. On the air pollution side low emissions of nitrogen and sulphur oxides have received a lot of attention. The control of particulate emission less so. In this paper the character of the particulate emissions will be discussed and the operating experience with Flakt electrostatic precipitators (ESP) and fabric filters (FF) for this application reviewed. Tests have been performed at Kauttua on several occasions with peat only, coal and peat, as well as coal with limestone addition to the bed. Tests performed by the Finnish test institution VTT when firing peat only gave under conditions close to those of the guarantee emissions below 50 mg/m/sup 3/ norm. Of particular interest is however the tests performed at Kauttua by Studsvik Energiteknik AB, Sweden when firing coal with and without limestone addition to the bed. The tests formed part of the investigation programme within the Swedish Coal-Health-Environment (K-H-M) project. As the same test methods etc. were used for these as well as other tests within the programme, the results are comparable with those made after other boilers firing coal, as well as those firing other fuels. The measurement programme incorporated both particulates and gases including polyaromatic hydrocarbons.

Maartmann, S.; Kreminski, J.

1983-11-01

70

Atmospheric fluidized-bed combustion. Technology status report  

SciTech Connect

The goal of DOE/METC's AFBC activities is to establish an engineering technology base by 1990, from which the industrial, commercial, and residential sectors can build and operate coal-fired AFBC systems. These systems will be capable of economically generating process steam, direct and indirect heat, and onsite electric power from coals of all ranks and sulfur contents in an environmentally acceptable manner. First-generation atmospheric fluidized-bed technology is considered commercial; a number of US boiler manufacturers are offering commercial units. However, many of these first units are products of empirical design and offer marginal gains in economics, performance, and reliability over conventional systems. In order to resolve the remaining technical issues and to broaden the market, DOE is pursuing advanced concepts. Development of this second-generation AFBC technology is directed toward small industrial, commercial, and residential applications. Penetration of these potential markets will require: (1) a 20 to 30% reduction in capital and operating costs over first-generation technology; (2) significant improvements in performance and reliability; and (3) compliance with existing and proposed New Source Performance Standards for environmental emissions. Current AFBC activities address: industrial operations, advanced concepts, and technology development. Four AFBC demonstration projects were active in FY 1984. The development of AFBC technology is directly supported by the evaluation of five advanced concepts by the M.W. Kellogg Company (circulating-bed FBC), Battelle Columbus Laboratories (spouted-bed FBC), Aerojet Energy Conversion Company (moving-bed FBC), Howard University (staged cascade FBC), and Arthur D. Little, Inc. (pulsed-bed FBC). These concepts may improve the economics and performance. 13 refs., 11 figs.

Not Available

1984-10-01

71

NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project  

SciTech Connect

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)

Not Available

1992-02-01

72

Advanced atmospheric fluidized-bed combustion design. Final report  

SciTech Connect

In the process of the design study, the UAFBC system configuration has been evolved and simplified. The system combines a self-cleaning distributor/grate section (which can tolerate large coal particles) with a fluidized bed. Proper control of the distributor/grate and fluidized-bed provides high turndown capability. For maximum carbon utilization, an afterburner is provided. NO/sub x/ control is achieved by proper combustion staging and temperature control. For SO/sub x/ control, an entrained-bed sulfur scrubber, which uses small sorbent particles and long solids stay times yields efficient sulfur capture with a low calcium/sulfur ratio. The Aerojet design approach is to provide enough functional separation in the system to allow the stringent design goals to be satisfied compatibly. Various known state-of-the-art subsystems - self cleaning distributor/grate, fluidized-bed combustor, fines afterburner, entrained-bed dry scrubber - have been integrated to make this possible. The coordinated operation of the system elements is accomplished through the use of modern microprocessor controls. In this way, close control is obtained over the mechanisms of the combustion, sulfur scrubbing and particle cleanup processes without undue complexity. This high degree of process control permits development of a combustor which should exceed present environmental standards for NO/sub x/, SO/sub x/, and particulates, while allowing operation with an 8:1 turndown using a wide variety of fuels. In the design study, a number of configurations were considered and analyzed by computer simulation. Performance projections were made for various power levels and, in the case of the bench-scale system, for three different coal feeds. Greer limestone (75 wt % CaCO/sub 3/) was used as the reference sulfur sorbent. The results showed potentials for rapid commercialization of small (50,000 lb/h steam) UAFBC systems. 56 refs, 79 figs., 35 tabs.

Rudnicki, M.I.; Jassowski, D.M.; Mah, C.S.; Newton, R.A.

1985-01-01

73

Experience with atmospheric fluidized bed gasification of switchgrass  

SciTech Connect

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

Smeenk, J.; Brown, R.C. [Iowa State Univ., Ames, IA (United States). Center for Coal and the Environment

1998-12-31

74

Particulate control experience after fluidized bed boilers firing coal  

Microsoft Academic Search

The energy crisis resulted in an intensified development of the fluidized bed boiler. In 1983, ten years later there are in the western world more than 100 units in operation or under construction. Manufacturers can offer designs with slow (bubbling) or fast (circulating) beds supported by more or less extensive experience. The fluidized bed combustor (FBC) has many advantages claimed

S. Maartmann; J. Kreminski

1983-01-01

75

6- x 6-ft atmospheric fluidized-bed combustion development facility and commercial-utility AFBC design assessment  

Microsoft Academic Search

Atmospheric Fluidized-Bed Combustion (AFBC) is being developed by the Electric Power Research Institute and Babcock and Wilcox as a possible alternative to the conventional pulverized coal boiler equipped with a wet (or dry) scrubber. This program comprises four tasks; three of which are covered in this report. An earlier report (EPRI CS-1688) documented the design and construction of the 6'

R. P. Apa; J. M. Bloss; P. L. Daniel

1983-01-01

76

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...

77

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 ...

78

Catalytic coal gasification in an internally circulating fluidized bed reactor with draft tube  

Microsoft Academic Search

Australian subbituminous coal loaded with the single and mixed catalysts of the alkali and transition metal salts [K2CO3, Ni(NO3)2, K2SO4, Ni(NO3)2+K2SO4] was gasified in an internally circulating fluidized bed (0.3m-I.D.×2.7m-high) with a draft tube (0.1m-ID×0.9m-high) at atmospheric pressure. Air and steam as the reactant gases were introduced into the draft tube and annulus regions in the bed separately. The effects

Jong Min Lee; Yong Jeon Kim; Sang Done Kim

1998-01-01

79

Utilization of coal ash from fluidized-bed combustion boilers as road base material  

Microsoft Academic Search

A process has been developed to utilize the large quantities of ash discharged from coal-fired fluidized-bed combustion boilers as road base material. Since the 1980s, the fluidized-bed boiler has been the subject of much study because it can burn fuels such as anthracite that cannot be burnt in pulverized coal-fired boilers and other conventional boilers, and because it eliminates the

T. Takada; I. Hashimoto; K. Tsutsumi; Y. Shibata; S. Yamamuro; T. Kamada; K. Inoue; K. Tsuzura; K. Yoshida

1995-01-01

80

Pulse enhanced fluidized bed combustion  

SciTech Connect

Various technologies are available for the combustion of high-sulfur, high-ash fuels, particularly coal. From performance, economic and environmental standpoints, fluidized bed combustion (FBC) is the leading candidate for utilization of high sulfur coals. ThermoChem, Inc., and the South Carolina Energy Research and Development Center (SCERDC) are installing a hybrid fluidized bed combustion system at Clemson University. This hybrid system, known as the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC), will augment the University`s steam system by providing 50--60,000 lbs/hr of saturated process steam. The PAFBC, developed by Manufacturing and Technology Conversion International, Inc., (MTCI), integrates a pulse combustor with a bubbling-bed-type atmospheric fluidized bed coal combustor. The pulse combustion system imparts an acoustic effect that enhances combustion efficiency, SO{sub 2} capture, low NO{sub x} emissions, and heat transfer efficiency in the fluidized bed. These benefits of pulse combustion result in modestly sized PAFBC units with high throughput rates and lower costs when compared to conventional fluidized bed units.

Mueller, B.; Golan, L. [South Carolina Energy Research and Development Center, Clemson, SC (United States); Toma, M.; Mansour, M. [Manufacturing and Technology Conversion International, Inc., Columbia, MD (United States)

1996-12-31

81

Pulsed atmospheric fluidized bed combustion. Quarterly technical progress report, October 1992--December 1992  

SciTech Connect

The Design and Engineering of most components in the Pulsed Atmospheric Fluidized Bed System was completed prior to September 1992. The components remaining to be designed at that time were: Aerovalves for the Pulse Combustor; Gas and coal injectors for the Pulse Combustor; Lines for PC tailpipes; Air plenum and inlet silencer; Refractory lined hot gas duct connecting outlet hot cyclone to boiler; Structure and platforms, and ladders around PAFBC vessel access and major equipment. Design work is currently in progress on all of the above components. Items 1, 2, 3 and 4 are 50% completed, and items 5 & 6 are 75% complete.

Not Available

1993-01-01

82

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

SciTech Connect

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.

P. Abelha; I. Gulyurtlu; I. Cabrita [Instituto Nacional de Engenharia, Lisbon (Portugal)

2008-01-15

83

Ash vaporization in circulating fluidized bed coal combustion  

SciTech Connect

In this work, the vaporization of the ash-forming constituents in circulating fluidized bed combustion (CFBC) in a full-scale 80 MW{sub th} unit was studied. Ash vaporization in CFBC was studied by measuring the fly ash aerosols in a full-scale boiler upstream of the electrostatic precipitator (ESP) at the flue gas temperature of 125{degree}C. The fly ash number size distributions showed two distinct modes in the submicrometer size range, at particle diameters 0.02 and 0.3 {mu}m. The concentration of the ultrafine 0.02-{mu}m mode showed a large variation with time and it decreased as the measurements advanced. The concentration of the 0.02-{mu}m mode was two orders of magnitude lower than in the submicrometer mode observed earlier in the bubbling FBC and up to three orders of magnitude lower than in the pulverized coal combustion. Scanning electron micrographs showed few ultrafine particles. The intermediate mode at 0.3 {mu}m consisted of particles irregular in shape, and hence in this mode the particles had not been formed via a gas to particle route. We propose that the 0.3-{mu}m mode had been formed from the partial melting of the very fine mineral particles in the coal. The mass size distribution in the size range 0.01-70 {mu}m was unimodal with maximum at 20 {mu}m. Less than 1% of the fly ash particles was found in the submicrometer size range. 35 refs., 8 figs., 3 tabs.

Lind, T.; Kauppinen, E.I.; Maenhaut, W. [Univ. of Gent (Belgium); Shah, A.; Huggins, F. [Univ. of Kentucky, Lexington, KY (United States)

1996-04-01

84

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...

85

Evolution of hydrogen sulfide in a fluidized bed coal gasification reactor  

Microsoft Academic Search

The rates of evolution of hydrogen sulfide have been measured for the steam\\/oxygen gasification of a devolatilized Western Kentucky bituminous coal, a New Mexico subbituminous coal, and a Texas lignite in a pilot-scale fluidized bed reactor, and a phenomenological model has been formulated to correlate the results. The model assumes instantaneous devolatilization and partial combustion of the coal followed by

Robert P. Ma; Richard M. Felder; James K. Ferrell

1989-01-01

86

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

SciTech Connect

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.

Ashworth, R.A.; Plessinger, D.A.; Sommer, T.M. [Energy and Environmental Research Corp., Orville, OH (United States); Keener, H.M. [Ohio Agricultural Research and Development Center, OH (United States); Webner, R.L. [Will-Burt Co., Orrville, OH (United States)

1997-03-31

87

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...

88

ASSESSMENT OF A MODEL WITH CHAR ATTRITION FOR A BUBBLING ATMOSPHERIC FLUIDIZED-BED COMBUSTOR  

Microsoft Academic Search

A comprehensive model, previously developed and tested for prediction of behavior of continuous fluidized-bed combustors, is extended to incorporate char attrition and is applied to the simulation of a 0.3 MegaWatt (MW) atmospheric bubbling fluidized-bed combustor burning lignites with high Volatile Matter\\/Fixed Carbon (VM\\/FC) ratios in their own ashes. The effect of this incorporation is assessed by comparing the predictions

Yusuf Gogebakan; Nevin Selçuk

2004-01-01

89

Fluidized-bed combustion  

SciTech Connect

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.

Botros, P E

1990-04-01

90

Characteristics of Pyrolytic Topping in Fluidized Bed for Different Volatile Coals  

NASA Astrophysics Data System (ADS)

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.

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

91

Effects of NH3 on N2O formation and destruction in fluidized bed coal combustion  

NASA Astrophysics Data System (ADS)

The NH3 oxidation and reduction process are experimentally and kinetically studied in this paper. It is found that NH3 has contributions not only to N2O formation, but also to N2O destruction in certain conditions. The main product of homogeneous NH3 oxidation is found to be NO rather than N2O, but some bed materials and sulphur sorbents have catalytic contributions to N2O formation from NH3 oxidation. In reduction atmosphere, NH3 can promote the KC destruction. It is deduced that the ammonia injection into fluidized bed coal combustion flue gas can decrease both NOx and N2O emissions. The ammonia injection process is kinetically simulated in this study, and the reduction rates of NOx and N2O are found to depend on temperature, O2 concentration, initial NOx and N2O concentrations, and amount of injected ammonia.

Yuan, Jianwei; Feng, Bo; Lu, Jianxin; Liu, Hao; Liu, Dechang

1994-12-01

92

In-situ oxygen probe data from a fluidized-bed coal combustor  

SciTech Connect

There is considerable current interest in the use of stabilized zirconia oxygen probes to continuously monitor the oxygen partial pressure during the combustion of coal in a fluidized bed of limestone. These data are sought to provide insight into the nature of the combustion process in particular locations of the fluidized-bed combustor (FBC) and as an aid in characterizing the corrosive nature of the environment which will surround in-bed heat transfer tubes. A growing body of data gathered through the use of such in-situ oxygen probes suggests the existence of areas of very low and/or oscillating oxygen partial pressures within the dense bed of fluidized combustors. If these data are real, research to interpret the causes of the excursions to low oxygen partial pressures may provide keys to rational materials selection and FBC design. A calcia-stabilized zirconia electrolyte cell was used to characterize the oxygen partial pressure in Battelle's 0.6 m (2 ft) diameter atmospheric FBC as a function of location in the combustor and of operating conditions. This paper describes the data obtained when the bed was run at 900 C (1650 F) with Illinois No. 6 coal and limestone, with a superficial velocity of 2 m/sec (6.5 ft) at conditions of 50% and 20% excess air. Coal was fed into the bed through a single port in the center of the base plate. The bed contained an air-cooled heat exchanger, which consisted of a bank of 5 cm (2 in.) OD U-bend tubes on 15 cm (6 in.) centers that entered and returned through the west wall of the FBC.

Not Available

1982-01-01

93

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

DOEpatents

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.

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

1981-09-14

94

MUTAGENICITY AND CYTOTOXICITY OF COAL FLY ASH FROM FLUIDIZED-BED AND CONVENTIONAL COMBUSTION  

EPA Science Inventory

Two respirable coal fly-ash samples (3 micrometers) were evaluated for physical properties chemical composition, and biological activity, including cytotoxicity and mutagenicity. These two fly-ash samples were collected from a pressurized fluidized-bed combustion miniplant and fr...

95

Combustion of olive cake and coal in a bubbling fluidized bed with secondary air injection  

Microsoft Academic Search

Combustion performances and emission characteristics of olive cake and coal are investigated in a bubbling fluidized bed. Flue gas concentrations of O2, CO, SO2, NOx, and total hydrocarbons (CmHn) were measured during combustion experiments. Operational parameters (excess air ratio (?), secondary air injection) were changed and variation of pollutant concentrations and combustion efficiency with these operational parameters were studied. The

Murat Varol; Aysel T. Atimtay

2007-01-01

96

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

Microsoft Academic Search

This work was undertaken with the aim of quantifying the relative amounts of NH 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 released and the levels of NOX and NO formed during cocombustion was

P. Abelha; I. Gulyurtlu; I. Cabrita

2008-01-01

97

Mixing and combustion in a coal-limestone fluidized bed combustor  

Microsoft Academic Search

Task 1 was to investigate experimentally the characteristics of solids mixing between coal and limestone in a cold fluidized bed; Task 2 was to derive a model to describe the behavior of solids mixing observed in Task 1; and Task 3 was to develop a combustor model, which couples the mixing model derived in Task 2 with a combustion model,

Kirkpatrick

1987-01-01

98

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

Microsoft Academic Search

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°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

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

1981-01-01

99

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

EPA Science Inventory

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

100

Operating Experience of a Coal Fired Fluidized Bed at Georgetown University  

E-print Network

Operation of the 100,000 lb/hr capacity, coal fired fluidized bed steam generator at Georgetown University began in July 1979. This project, which was co-funded by Georgetown University and the U. S. Department of Energy, involved expansion...

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

1980-01-01

101

DYNAMIC MODELING OF A PILOT-SCALE FLUIDIZED-BED COAL GASIFICATION REACTOR  

EPA Science Inventory

The paper describes a dynamic mathematical model of a pressurized fluidized-bed coal gasification reactor, developed and used to correlate data from a pilot-scale reactor. The model accounts for pyrolysis, oxidation, char gasification and subsequent gas-phase reactions, fines elu...

102

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...

103

Combustion of coal in circulating fluidized-bed boilers: a review  

Microsoft Academic Search

Fuel cost is the single most important operating cost in a circulating fluidized bed boiler. A well-designed CFB boiler can burn coal with a fairly high efficiency and within acceptable levels of gaseous emission. However, departure from ideal operating conditions, which often occurs in operating plants, throws the plant far off the designed performance. A good understanding of the combustion

P. Basu

1999-01-01

104

INVESTIGATION OF TYRES AND COAL COMBUSTION IN A LABORATORY SCALE FLUIDIZED BED COMBUSTOR  

Microsoft Academic Search

Study of tyre and coal combustion in a laboratory scale fluidized bed reactor is presented. The combustion studies were performed with particles obtained from the Slovak brown coal (mine Handlová) and the scrap waste automobile tyres (EKO Beluša). Coal particle sizes of 0,51- 0,7 mm and the fraction of waste tyres 0.8 - 2 mm were used. The samples of

Kristína Holíková; Július Annus

105

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

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

106

Simulation modeling of fluidized bed coal gasifier for new topping cycle system  

SciTech Connect

A new topping cycle coal power generation process is to be developed as a Japanese national project of high efficiency power generation process of coal. This process consists of a combination system of a pressurized bubbling fluidized-bed coal gasifier and a pressurized bubbling fluidized-bed combustor in series. To evaluate the performances and also to determine specifications and operation parameters of this process, it is extremely important to analyze the behavior and the performance of this system by a reasonable simulation model. A simulation model of this new process is developed in this paper. It is demonstrated by calculated results from this model that the carbon conversion in the gasifier, the composition and the heating value of produced gas are strongly dependent on operating conditions. Heat recovery by the steam in the combustor is also estimated as the function of coal feed rate.

Piao, Guilin; Yamazaki, Ryohei; Mori, Shigekatsu; Fujima, Yukihisa [Nagoya Univ. (Japan). Dept. of Chemical Engineering

1997-12-31

107

Fluidized bed heat processing  

SciTech Connect

A review of fluidized-bed processing and the general nature of heat transfer versus gas velocity in a fluidized bed includes comparisons of heating rates and descriptions of applications. Among the latter, are batch units for hardening and tempering. The fast process times possible with fluidized beds make them particularly suitable for continuous heat treating such as the processing of wire and hardening of small parts. Future directions include increasing the maximum operating temperature to 1300 degrees C. for atmosphere furnaces through the use of special non-metallic retorts for the processing high-speed tool steels and the increased usage of fluidized beds in scrap metal reclamation. 10 figures.

Fennell, A.G.

1985-08-01

108

Co-combustion of peach and apricot stone with coal in a bubbling fluidized bed  

Microsoft Academic Search

In this study a bubbling fluidized bed combustor (BFBC) having an inside diameter of 102 mm and a height of 900 mm was used to investigate the co-combustion characteristics of peach and apricot stones produced as a waste from the fruit juice industry with coal. A lignite coal was used for co-combustion. On-line concentrations of O2, CO, CO2, SO2, NOX and total

Aysel T. Atimtay; Burçak Kaynak

2008-01-01

109

An Experimental Investigation into the Fragmentation of Coal Particles in a Fluidized-Bed Combustor  

Microsoft Academic Search

\\u000a The fragmentation of coal plays a significant role in combustion in fluidized-bed boilers because it accelerates combustion\\u000a and influences the distribution of particle sizes in the bed. Fine char particles produced by comminution can be carried out\\u000a and increase the heat loss due to incomplete carbon conversion. The thermal fragmentation depends on the initial structure\\u000a of the coal and how

Monika Kosowska-Galacbowska; Adam Luckos

2010-01-01

110

Mutagenicity and cytotoxicity of coal fly ash from fluidized?bed and conventional combustion  

Microsoft Academic Search

Two respirable coal fly?ash samples (? 3 ?m) were evaluated for physical properties, chemical composition, and biological activity, including cytotoxicity and mutagenicity. These two fly?ash samples were collected from a pressurized fluidized?bed combustion miniplant and from a conventional?combustion power plant, both burning eastern coal. All samples were collected by a fabric filter downstream of the plant particulate control devices at

Judy Lee Mumford; Joellen Lewtas

1982-01-01

111

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

NASA Astrophysics Data System (ADS)

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

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

112

Tubing wastage in fluidized-bed coal combustors (Grimethorpe PFBC (pressurized fluidized-bed combustion) Tube Bank E'')  

Microsoft Academic Search

Samples of evaporator tubing from Tube Bank E'' of the Grimethorpe pressurized fluidized-bed combustion (PFBC) facility in the UK were examined in the third of a series of studies being conducted at Lawrence Livermore National Laboratory (LLNL) under sponsorship of the US Department of Energy's Morgantown Energy Technology Center (METC). The program is being conducted to identify the mechanism or

Witherell

1989-01-01

113

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

SciTech Connect

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.

Jack A. Fuller; Harvie Beavers; Robert Bessette [West Virginia University, Morgantown, WV (United States). College of Business and Economics

2006-06-15

114

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

SciTech Connect

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.

Not Available

1992-05-01

115

Study of the combustion of low rank coal in a fluidized bed  

SciTech Connect

This report describes the results of preliminary combustion tests performed with Eagle Butte Coal in a bubbling, fluidized-bed combustion system. The system was designed for the combustion of low-rank coals and industrial wastes. The work, as proposed, was aimed at not only the evaluation of co-firing of waste material with coal, but also at developing modifications to first generation bubbling bed designs to improve the combustion performance during co-firing. However, the funding for the work was redirected and the combustion tests were suspended soon after the shakedown testing was completed. Consequently, this report describes the results of the tests completed prior to the redirection of the effort and funding. A total of 33 combustion tests were performed in a 6-inch diameter fluidized-bed combustor. Oxygen concentrations were measured at two points in the system; the vent line and at the interface between the fluid bed and the freeboard. These measurements provided a measure of the amount of conversion of coal within the fluidized bed compared to the conversion in the freeboard region. Typically, 75 to 80% of the conversion occurred within the bed. Several experiments were performed in which special bed internals were placed in the bed. The internals were designed to reduce bubble size in the bed thus increasing the surface area of the bubbles and hence promoting oxygen diffusion into the emulsion phase.

Glaser, R.; Grimes, R.W.

1991-09-01

116

Mixing and combustion in a shallow coal-limestone fluidized bed combustor  

Microsoft Academic Search

A model based on the Monte Carlo approach was developed to simulate the mixing and combustion behavior of a shallow coal-limestone fluidized bed combustor. The model involved the coupling of two sub-models: a combustion sub-model based on the two-phase concept of fluidization and a mixing sub-model based on our previously developed dynamic mixing model. The combustion sub-model considered both the

T. C. Ho; M. Kirkpatrick; J. R. Hopper

1987-01-01

117

Dynamic modeling of a pilot-scale fluidized-bed coal gasification reactor  

Microsoft Academic Search

A dynamic mathematical model of a pressurized fluidized-bed coal gasification reactor has been developed and used to correlate data from a pilot-scale reactor. The model accounts for pyrolysis, oxidation, char gasification, and subsequent gas-phase reactions, fines elutriation and heat losses from the reactor, and simulates both transient and steady-state operation. If the values of three model parameters are adjusted to

R. Russell Rhinehart; Richard M. Felder; James K. Ferrell

1987-01-01

118

Development of seal legs for atmospheric fluidized-bed combustion (AFBC) applications  

Microsoft Academic Search

The use of fly ash recycle systems with bubbling atmospheric fluidized-bed combustion systems (AFBC) requires feed systems able to meter erosive, high temperature ash at up to 15-psi back pressure. Mechanical systems providing such pressure seals are complex, space consuming, and require significant maintenance to keep them operating. This report summarizes the research and development efforts leading to the successful

1990-01-01

119

Atmospheric fluidized-bed combustion waste utilization in cement and sulfuric acid: Preliminary feasibility study  

Microsoft Academic Search

An OACD interdisciplinary project team has investigated the preliminary feasibility of using atmospheric fluidized-bed combustion (AFBC) waste in the production of portland cement and sulfuric acid. This investigation found that it is technically and economically feasible to simultaneously produce electricity, portland cement, and sulfuric acid in an environmentally clean, integrated industrial complex. This complex would include a 500-MW AFBC unit

D. G. Salladay; D. E. Nichols; J. T. Berry; D. B. Call; E. A. Harre; Y. K. Kim

1986-01-01

120

Inactivation of Salmonella Enteritidis PT 30 on Almonds with a Fluidized Bed Atmospheric Pressure Plasma  

E-print Network

Inactivation of Salmonella Enteritidis PT 30 on Almonds with a Fluidized Bed Atmospheric Pressure for the treatment of Salmonella Enteritidis PT 30 on almonds. Each almond sample was spot inoculated with 10 µl is not conducive for microorganisms to multiply. Salmonella however can survive for extended periods under

Heller, Barbara

121

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...

122

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

SciTech Connect

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.

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

1982-06-01

123

Nitrogen Oxides, Sulfur Trioxide, and Mercury Emissions during Oxy-fuel Fluidized Bed Combustion of Victorian Brown Coal.  

PubMed

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

Roy, Bithi; Chen, Luguang; Bhattacharya, Sankar

2014-12-16

124

Conceptual design of a coal-fired fluidized-bed steam locomotive  

SciTech Connect

This paper describes a conceptual design of a coal-fired, fluidized-bed, combustor-based steam locomotive that was developed as an approach to displacing premium fuel (diesel). This approach draws on relatively mature technology and appears feasible for the near term. Guidelines for the conceptualization are based on two previous designs that are relatively contemporary, and were built and tested during the steam locomotive era. Conclusions of this conceptual design study are summarized as follows: (1) a total conversion from diesel locomotives to coal-fired steam locomotives would displace up to 280,000 barrels of oil per day; (2) a fluidized-bed, steam turbine locomotive has the potential to offer very significantly lower operating costs and environmental burdens than the diesel; (3) fuel operating costs per horsepower hour for three comparably sized systems are as follows: diesel - $.19, fluidized-bed combustion (FBC) condensing steam cycle - $.085, and the FBC noncondensing steam cycle - $.021; (4) a cost estimate to build one commercially proven (post-prototype) coal-fired, fluidized-bed locomotive unit is estimated at $3,400,000; (5) an environmental analysis indicates that effective SO/sub 2/ and NO/sub x/ control is readily attainable with the FBC approach. If industrial New Source Performance Standards (NSPS) are imposed, particulate emission is likely to be the most severe constraint to FBC rail applications; (6) in general, there are no insurmountable roadblocks to early commercialization of mobile FBC steam generators, based on this analysis; and (7) in addition, the development of an attractive, mobile FBC power system appears to have significant potential for marine applications and industrial steam generators, either for direct heating or cogeneration applications.

Csamer, R.P.

1981-04-01

125

[Pulsed atmospheric fluidized bed combustion (PAFBC)]. Technical progress report, February 1989--April 1989  

SciTech Connect

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

Not Available

1989-05-01

126

Fluidized bed boiler feed system  

DOEpatents

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.

Jones, Brian C. (Windsor, CT)

1981-01-01

127

Fabric filter testing at the TVA Atmospheric Fluidized-bed Combustion (AFBC) Pilot Plant  

Microsoft Academic Search

Experience with fluidized bed combustion (FBC) units on a research and industrial scale has indicated that FBC power plants could be a viable alternative to pulverized-coal power plants with wet limestone scrubbers or spray dryers. To provide design confidence and the flexibility to evaluate process improvements, the Tennessee Valley Authority constructed a 20-MW(e) AFBC (bubbling bed) Pilot Plant. Subseqently, EPRI

K. M. Cushing; P. V. Bush; T. R. Snyder

1988-01-01

128

An Experimental Investigation into the Fragmentation of Coal Particles in a Fluidized-Bed Combustor  

NASA Astrophysics Data System (ADS)

The fragmentation of coal plays a significant role in combustion in fluidized-bed boilers because it accelerates combustion and influences the distribution of particle sizes in the bed. Fine char particles produced by comminution can be carried out and increase the heat loss due to incomplete carbon conversion. The thermal fragmentation depends on the initial structure of the coal and how this structure changes with an increase in temperature when the particle is dropped into the combustion chamber. Experinments with nine Polish coals were carried out to quantify the fragmentation of burning coal particles. A bench-scale bubbling fluidized bed combustor was used to determine the degree of fragmentation for spherical coal particles during devolatilization and combustion. The effects of bed temperature, particle size and coal properties on the extent of primary and secondary fragmentation have been determined. It has been found that the combination of low porosity and high volatile content is the main factor responsible for the observed extent of fragmentation.

Kosowska-Galacbowska, Monika; Luckos, Adam

129

Hybrid fluidized bed combuster  

SciTech Connect

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.

Kantesaria, Prabhudas P. (Windsor, CT); Matthews, Francis T. (Poquonock, CT)

1982-01-01

130

Characterizing fuels for utility-scale atmospheric fluidized-bed combustors: Volume 2, Appendixes  

Microsoft Academic Search

The Electric Power Research Institute is sponsoring development of a new method of characterizing fuels for bubbling atmospheric fluidized-bed combustion (AFBC) boilers. Compared to today's alternative of testing at a large-scale AFBC unit, the fuels characterization method will allow low-cost characterization for utilities considering AFBC applications or a change of fuel in an existing unit. The method utilizes bench-scale test

R. R. Chandran; J. N. Duqum; H. C. Jafari; D. R. Rowley; M. A. Perna

1989-01-01

131

Characterizing fuels for utility-scale atmospheric fluidized-bed combustors: Volume 1, Initial development  

Microsoft Academic Search

The Electric Power Research Institute is sponsoring development of a new method of characterizing fuels for bubbling atmospheric fluidized-bed combustion (AFBC) boilers. Compared to today's alternative of testing at a large-scale AFBC unit, the fuels characterization method will allow low-cost characterization for utilities considering AFBC applications or a change of fuel in an existing unit. The method utilizes bench-scale test

R. R. Chandran; J. N. Duqum; H. C. Jafari; D. R. Rowley; M. A. Perna

1989-01-01

132

Technology assessment for an atmospheric fluidized-bed combustion demonstration plant  

SciTech Connect

This study assesses the atmospheric fluidized-bed combustion (AFBC) technology with respect to design, construction, and operation of a demonstration power plant in the range of 150 to 250 MW(e) capacity and identifies the most critical research and development needs for the plant project. The general conclusion of these studies is that AFBC is feasible for large power plants and that it has a generally good potential for providing an economically and environmentally acceptable alternative to conventional coal-fired power plants. Several areas of technical uncertainty must, however, be resolved in order to ensure success of an AFBC demonstration plant project. Much of the existing data base for AFBC comes from small-scale test units, and much of it is still inconclusive. A number of operational and design problems exist that do not yet have conclusive answers. A focused research and development program aimed at the early resolution of these problems should be carried out to ensure successful construction and operation of the proposed AFBC demonstration plant and early commercialization of the technology. A large flexible feeding test facility designed to investigate the feeding problems and possibilities should be constructed. A materials-test facility is also needed for testing, evaluating and selecting materials, as well as demonstrating their long-term compatibility. An intermediate-size pilot plant with sufficient flexibility to test alternate solutions to the above-mentioned problems will considerably strengthen the demonstration program.

Siman-Tov, M; Jones, Jr, J E

1980-01-01

133

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

SciTech Connect

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

Peltier, R.

2007-08-15

134

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

PubMed

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

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

2002-01-01

135

New approach to understanding NO emission during bubbling fluidized bed coal combustion: separation of NO formation and reduction processes in the bed  

Microsoft Academic Search

A new approach for separately evaluating NO formation and NO reduction during coal combustion in a fluidized bed was investigated. Sixteen different coals were burned in a laboratory-scale bubbling fluidized bed combustor with three different char loadings, which were established by changing the inlet oxygen concentrations. NO conversion ratios (X{sub NO} = the ratio of the mass of N atoms

Takahiro Murakami; Yoshizo Suzuki; Abdullah Khan Durrani

2009-01-01

136

Coal gasification in a pilot scale fluidized bed reactor. 2. Gasification of a New Mexico subbituminous coal  

Microsoft Academic Search

A New Mexico subbituminous coal was gasified with steam and oxygen in a 15.2 cm i.d. fluidized bed reactor at a pressure of 790 kPa (100 psig) and average bed temperatures between 875 and 990°C. Material balances were obtained on total mass and major elements (C, H, O, N, S). A simple representation of coal pyrolysis has been added to

Mark J. Purdy; Richard M. Felder; James K. Ferrell

1984-01-01

137

Simulation of coal gasification in a fluidized bed  

SciTech Connect

In this analysis of coal gasification, a fundamental approach is used where a set of multiphase (Eulerian) fluid dynamic equations, obtained either by a suitable averaging technique (Anderson and Jackson, 1976; Drew, 1971) or the formulations of continuum mechanics (Drew, 1983), is used to describe the conservation of mass, momentum, and energy for three interpenetrating phases. The particles, like the fluidizing gas, are described as interpenetrating continua. Different particle types are treated as distinct phases; in this study, the feed coal and the bed char are represented as separate phases in order to account for their different histories. Constitutive laws account for the exchange of momentum between phases (``drag``) and interphase energy transfer. The stresses within the granular phases are determined by a formulation based on the kinetic theory, characterized by a ``granular temperature``. A computer code, based on this multiphase hydrodynamic model, has been developed at the Morgantown Energy Technology Center for the detailed simulation of gas and particle dynamics in heavily loaded coal conversion processes (Syamlal, Rogers, O`Brien, 1994; Syamlal, 1995). The hydrodynamic simulation showed the reactor operated in a jetting/bubbling mode. A gas jet penetrated a considerable distance into the bed, and then detached as ``bubbles`` which rose to the top of the column. The reaction scheme indicated that the feed coal did not begin to devolatilize until it had traversed this region, because of the time required to heat up. Thus, volatiles were not released in the jetting region of the bed, but higher in the bed. The oxygen fed with the coal, however, reacted immediately with the recirculating hot char. The net effect of the char reaction scheme was to created. CO, which burned in the region where.the jet detached, creating a, fairly stable ``flame``. The tar reaction scheme indicated that none of the tar escaped the bed.

O`Brien, T.J.

1996-12-31

138

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

SciTech Connect

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.

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

1993-01-01

139

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

SciTech Connect

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.

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

1993-03-01

140

Tennessee Valley Authority atmospheric fluidized-bed combustor simulation interim annual report, January 1December 31, 1980  

Microsoft Academic Search

A detailed description of the work performed during 1980 for the Tennessee Valley Authority (TVA) in support of the TVA Fluidized-Bed Combustion (FBC) Demonstration Plant Program is presented. The work was carried out under Task 4, modeling and simulation of atmospheric fluidized-bed combustion (AFBC) systems. The overall objective of this task is to develop a steady-state mathematical model with the

J. W. Wells; M. H. Culver; R. P. Krishnan

1981-01-01

141

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

Microsoft Academic Search

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

J. W. Wells; R. P. Krishnan

1980-01-01

142

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

NASA Technical Reports Server (NTRS)

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.

Kobak, J. A.

1979-01-01

143

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

NASA Astrophysics Data System (ADS)

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.

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

1996-11-01

144

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

SciTech Connect

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.

DeLallo, M.; Zaharchuk, R.

1994-01-01

145

Effect of freeboard extension on co-combustion of coal and olive cake in a fluidized bed combustor  

Microsoft Academic Search

In this study, flue gas emissions and combustion efficiencies during combustion and co-combustion of olive cake and coal were investigated in a bubbling fluidized bed. Temperature distributions along the combustion column and flue gas concentrations of O2, CO, SO2 and NOx were measured during combustion experiments. Two sets of experiments were performed to examine the effect of fuel composition, excess

Onur Akpulat; Murat Varol; Aysel T. Atimtay

2010-01-01

146

Plastic waste elimination by co-gasification with coal and biomass in fluidized bed with air in pilot plant  

Microsoft Academic Search

Treatment of plastic waste by gasification in fluidized bed with air using dolomite as tar cracking catalyst has been studied. The gasifier has a 1 m high bed zone (diameter of 9.2 cm) followed by a 1 m high freeboard (diameter of 15.4 cm). The feedstock is composed of blends of plastic waste with pine wood sawdust and coal at

María P. Aznar; Miguel A. Caballero; Jesús A. Sancho; E. Francés

2006-01-01

147

Coal slurry solids/coal fluidized bed combustion by-product mixtures as plant growth media  

USGS Publications Warehouse

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.

Darmody, R.G.; Green, W.P.; Dreher, G.B.

1998-01-01

148

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

SciTech Connect

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.

Gilkey, C.H.; Mergler, T.G. [ABB Air Preheater, Inc., Wellsville, NY (United States); Muller-Odenwald, H. [Kraftanlagen Abgastechnik GmbH, Bammental (Germany); Francin, P. [GEC Alsthom-Stein Industrie, Lys-Lez-Lannoy (France); Sakashita, Susumu [ABB Gradelius K.K., Kobe (Japan)

1995-12-31

149

Mixing and combustion in a shallow coal-limestone fluidized bed combustor  

SciTech Connect

A model based on the Monte Carlo approach was developed to simulate the mixing and combustion behavior of a shallow coal-limestone fluidized bed combustor. The model involved the coupling of two sub-models: a combustion sub-model based on the two-phase concept of fluidization and a mixing sub-model based on our previously developed dynamic mixing model. The combustion sub-model considered both the volatile and char combustion. It assumed that the combustor consisted of three distinct phases, i.e., jet, bubble and emulsion, with combustion occurring only in the emulsion phase. The mixing sub-model considered the upward or downward movement of a coal particle in the bed as being governed by certain probability laws; these laws were, in turn, affected by the bubbling hydrodynamics. In all, the combustor simulation model took into consideration the effects of coal feed rate, coal size distribution, limestone size, air flow rate and combustor temperature on the combustor behavior. The simulation results included the dynamic response of coal concentration profile, coal size distribution, coal particle elutriation rate as well as the mixing status between the coal and limestone particles.

Ho, T.C.; Kirkpatrick, M.; Hopper, J.R.

1987-01-01

150

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...

151

A mathematical model for pressurized circulating fluidized bed combustion  

SciTech Connect

Pressurized fluidized bed combustion is one of the most promising techniques for high efficiency and low emission power generation from hard and brown coal. Mathematical modeling and simulations may facilitate understanding, development and operation of this new process. Since 1980 at the Institute of Energy Technology of the University of Siegen, work has been carried out upon mathematical models for the simulation of fluidized bed coal combustion. This work comprises the simulation of steady state and transient behavior of atmospheric bubbling and circulating fluidized bed combustors based on hard and brown coal as well as the steam generator and the control system. This work has been extended to combined cycle processes by modeling the steady state behavior of a pressurized circulating fluidized bed combustor (PCFBC) for hard coal. In continuation of the former work it is intended to construct a comprehensive model from submodels based on physical and chemical principles and to avoid correlations for a certain plant. Based on recent publications from utility companies concerning the design of a PCFBC, a comparison of the steady state behavior of an atmospheric circulating fluidized bed combustor and pressurized circulating fluidized bed combustors at pressures of 5, 10, 15 and 20 bar was carried out. The simulation elucidates the influence of pressure on the axial temperature profile and the solid distribution in the combustion chamber, on CO-, NO- and SO{sub 2}-emissions and on the energy balance for the whole plant.

Heinbockel, I.; Fett, F.N. [Univ. of Siegen (Germany). Inst. of Energy Technology

1995-12-31

152

Attrition of coal ash particles in a fluidized-bed reactor  

SciTech Connect

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

Tomeczek, J.; Mocek, P. [Silesian Technical University, Katowice (Poland)

2007-05-15

153

Characteristics of co-combustion of anthracite with bituminous coal in a 200-MWe circulating fluidized bed boiler  

Microsoft Academic Search

The effect of co-combustion of Vietnamese anthracite with Australian bituminous coal on the performance of a commercial circulating fluidized bed boiler was observed in the Tonghae thermal power plant.The temperature in the cyclone exit of the boiler increased slightly, which caused a decrease in the desulfurization efficiency as the co-combustion ratio of the bituminous coal increased from 40 to 100%.

Jong Min Lee; Dong Won Kim; Jae Sung Kim

2011-01-01

154

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

Microsoft Academic Search

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

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

2009-01-01

155

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

E-print Network

Economic analysis of the construction and operation of by-product electric power and steam/power cogeneration systems in coal fired fluidized-bed steam cycles, located at individual industrial sites analyzed by the author, is being presented...

Mesko, J. E.

1980-01-01

156

Pilot-scale fluidized-bed combustor testing cofiring animal-tissue biomass with coal as a carcass disposal option  

Microsoft Academic Search

This study was performed to demonstrate the technical viability of cofiring animal-tissue biomass (ATB) in a coal-fired fluidized-bed combustor (FBC) as an option for disposing of specified risk materials (SRMs) and carcasses. The purpose of this study was to assess the technical issues of feeding\\/combusting ATB and not to investigate prion deactivation\\/pathogen destruction. Overall, the project successfully demonstrated that carcasses

Bruce G. Miller; Sharon Falcone Miller; Elizabeth M. Fedorowicz; David W. Harlan; Linda A. Detwiler; Michelle L. Rossman

2006-01-01

157

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

Microsoft Academic Search

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

Prinya Chindaprasirt; Ubolluk Rattanasak

2010-01-01

158

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

PubMed Central

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

Wang, Li-Qun; Chen, Zhao-Sheng

2013-01-01

159

Reduction of nitric oxide by carbonaceous solids in an atmospheric pressure fluidized-bed reactor  

Microsoft Academic Search

The fluidized-bed combustion process, due to its ability to control pollutant emissions and its inherent capability to accommodate a wide variety of fuels, has been the subject of accelerating development for industrial and utility applications. However, fluidized-bed combustion boilers based on the current design and operation may not be able to meet the future stringent standards on nitrogen oxides emissions

Z. Huang; G. T. Chen; C. Y. Wen; J. Y. Shang; J. S. Mei; J. E. Notestein

1982-01-01

160

Emissions of NO x and N 2O during co-combustion of dried sewage sludge with coal in a circulating fluidized bed combustor  

Microsoft Academic Search

Emissions of NOx and N2O were measured during mono-combustion of dried sewage sludge and co-combustion with coal in a bench-scale circulating fluidized bed combustor (CFBC). The results were compared with previous results obtained using a bubbling fluidized bed combustor (BFBC). The increase in NOx with sludge ash accumulation in the combustor was less for the CFBC than the BFBC, partly

Tadaaki Shimizu; Masanori Toyono

2007-01-01

161

Co-combustion of coal and biomass in a pressurized bubbling fluidized bed  

SciTech Connect

The use of biomass as an energy source in power plants has advantages compared to fossil fuel firing. Co-firing of biomass and coal offers additional advantages compared to exclusive biomass firing. The objective of the research described in this paper is to assess the effect of co-combustion of biomass (straw or Miscanthus Sinensis) and coal on the behavior of a pressurized fluidized bed combustor with regard to fuel feeding, fluidization, sintering, burnout, temperature distribution and the emission of harmful gaseous and solid components. Temperature and gas concentration profiles have been determined in the freeboard of the Delft 1.6 MW{sub th} PFBC test rig. The addition of up to 20% of biomass (based on heat input) has no adverse effect on the PFBC process. The feeding of the biomass is more critical than the feeding of coal, due to the more fibrous structure and the larger volumes of the biomass fuel. Dependent on the process conditions the biomass addition results locally in an increase or decrease of the temperatures. Biomass addition causes a small increase of the CO and NO and a small decrease of N{sub 2}O emissions. The influence of the biomass addition on the HCl emissions is not clear. The lower sulfur content and a larger sulfur capture efficiency result in lower SO{sub 2} emissions. The addition of biomass has a negligible influence on the combustion efficiency. A 15--30% higher cyclone catch was found for the coal/Miscanthus mixture when compared to the other fuels.

Andries, J.; Verloop, M.; Hein, K. [Delft Univ. of Technology (Netherlands)

1997-12-31

162

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

NASA Astrophysics Data System (ADS)

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.

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

1981-10-01

163

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

PubMed

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

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

2012-09-01

164

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

PubMed

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

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

2012-04-01

165

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

SciTech Connect

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.

Xiaolin Wei; Yang Wang; Dianfu Liu; Hongzhi Sheng; Wendong Tian; Yunhan Xiao [Chinese Academy of Sciences, Beijing (China). Institute of Mechanics, and Institute of Engineering Thermophysics

2009-03-15

166

Combustion in fluidized beds  

Microsoft Academic Search

Circulating fluidized-bed (CFB) combustion systems have become popular since the late 1970s, and, given the current level of activity in the area,it is clear that this technology has a stable future in the boiler market. For standard coal combustion applications, competition is fierce with mature pulverized-fuel-based (PF) technology set to maintain a strong profile. CFB systems, however, can be more

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

1990-01-01

167

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

SciTech Connect

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

Naruse, Ichiro; Saito, Katsuhiro; Murakami, Takahiro

1999-07-01

168

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

SciTech Connect

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.

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

1981-02-01

169

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

SciTech Connect

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.

Gulyurtlu, I.; Lopes, M.H.; Abelha, P.; Cabrita, I.; Oliveira, J.F.S. [INETI, Lisbon (Portugal)

2006-06-15

170

Biomass gasification in atmospheric and bubbling fluidized bed: Effect of the type of gasifying agent on the product distribution  

Microsoft Academic Search

The effect of the type of gasifying agent used in biomass gasification on product distribution (gas, char and tar yields) and gas quality (contents in H2, CO, CO2, CH4,…, tars) is analyzed. Gasifying agents taken into account are: air, pure steam, and steam–O2 mixtures. Process considered is biomass gasification in atmospheric and bubbling fluidized bed. Previous results got by Herguido

Javier Gil; José Corella; Mar??a P. Aznar; Miguel A. Caballero

1999-01-01

171

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

EPA Science Inventory

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

172

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...

173

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...

174

Numerical modeling of fluidized-bed combustor  

Microsoft Academic Search

Optimum design of fluidized-bed combustor requires high carbon burn-up, good sulfur retention, minimized sorbent (Ca) utilization, efficient feed distribution and mechanical layout. These parameters are strongly affected by the dynamics of the fluidized bed. The dynamic behavior of fluidized combustor is formulated in terms of multidomain - multiphase mechanics. Fluidization, bubble mechanics, coal combustion, sorbent sulfation, oxidation, solids movement and

W. T. Sha; S. L. Soo

1977-01-01

175

Coal combustion characteristics in a fluidized bed combustor with a draft tube  

Microsoft Academic Search

The effects of gas velocity to draft tube (3–6 Um), bed temperature (800–900?C) and excess air ratio (0–30%) on the total entrainment rate, overall combustion efficiency and\\u000a heat transfer coefficient have been determined in an internally circulating fluidized bed combustor with a draft tube. The\\u000a total entrainment rate increases with an increase in gas velocity to draft tube, but decreases

Woon-Jae Lee; Yong-Jun Cho; Jung-Rae Kim; Sang Done Kim

1992-01-01

176

Coal gasification in a pilot-scale fluidized bed reactor: 3. Gasification of a Texas lignite  

Microsoft Academic Search

A Texas lignite was gasified with steam and oxygen in a 15.2-cm-i.d. top-feeding fluidized bed reactor at a pressure of 810 kPa (103 psig), average bed temperatures between 1030 and 1200 K, and molar steam-to-carbon feed ratios from 1.0 to 2.5. In-bed gas and solids sampling results indicate that the water gas shift reaction is at or near thermodynamic equilibrium

R. Russell Rhinehart; Richard M. Felder; James K. Ferrell

1987-01-01

177

Development of pressurized internally circulating fluidized bed combustion technology  

SciTech Connect

Having an eye on higher efficiency and less installation space, emphasis has shifted to a pressurized fluidized bed boiler (PFBC) that enables combined cycle power generation by using a gas turbine. The paper describes an internally circulating fluidized bed boiler (ICFB), which is an atmospheric type with many actual installations. This is an original design and possesses unique a configuration that combines the advantages of both a bubbling type fluidized bed boiler and a circulating fluidized bed boiler. It offers various special features such as simple load variation capability, low environmental pollution characteristics, high combustion efficiency, and less immersed heating tube erosion while allowing use of a wide variety of fuel. This type of boiler (ICFB) can be successfully pressurized in such a way that it can meet new possibilities and characteristics that other conventional PFBCs could not offer. Ebara Corporation has carried out research and development on a project concerning the promotion of coal production and utilization technology subsidized by the Ministry of International Trade and Industry from the fiscal year 1992 in succession to this in-house research and review. In this paper, the authors introduce the features of their pressurized internally circulating fluidized bed boiler (PICFB) as well as report the present situation of the cold model tests now underway and the outline of the feasibility study for the 350 MWe PICFB.

Nagato, Shuichi; Miyoshi, Norihisa; Toyoda, Seiichiro; Oshita, Takahiro; Hosoda, Shugo [Ebara Corp., Tokyo (Japan). Environmental Plant Division

1995-12-31

178

Colorado-UTE circulating AFBC (atmospheric fluidized-bed combustion) demonstration: Volume 1, Project origin: Final report  

SciTech Connect

Poor station efficiency, high fuel costs, and increasingly high boiler-maintenance costs had forced the Nucla Station into a low position on the Colorado-Ute dispatch order. Among the options Colorado-Ute considered was the possibility of becoming a host utility to demonstrate atmospheric fluidized-bed combustion (AFBC) technology. The attractive economics and low environmental effects of circulating AFBC led to Colorado-Ute's decision in 1984 to proceed with the design and construction of a demonstration project at the Nucla Station. The company determined that in-place retirement of the three stoker-fired boilders and installation of a new circulating AFBC boiler would: Increase plant capacity from 36 KW to 110 MW for an investment of approximately $840kW; improve station heat rate by approximately 15%; reduce fuel costs (approximately 30%) by burning lower quality coal; reduce emissions to the point where New Source Performance Standards for SO/sub 2/ and NO/sub x/ could be met; and extend plant operating life by 30 years. Colorado-Ute: Reviewed the design, backup data, and experience base cited by the bidder; identified areas of technical risk; identified design studies and test programs that could mitigate the risks; developed fallback designs in case selected designs did not perform as predicted; assessed risk to the utility; and developed strategy for negotiating with the equipment supplier. Colorado-Ute judged that Pyropower's proposal had a lower combined capital and life-cycle cost, and therefore awarded it the Nucla Station circulating AFBC boiler contract. 7 refs., 10 figs., 11 tabs.

Blunden, W.E.

1988-05-01

179

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

SciTech Connect

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.

Sachs, M., E-mail: karl-ernst.wirth@fau.de; Schmitt, A., E-mail: karl-ernst.wirth@fau.de; Schmidt, J., E-mail: karl-ernst.wirth@fau.de; Peukert, W., E-mail: karl-ernst.wirth@fau.de; Wirth, K-E, E-mail: karl-ernst.wirth@fau.de [Institute of Particle Technology, University of Erlangen-Nuremberg (Germany)

2014-05-15

180

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

181

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

NASA Astrophysics Data System (ADS)

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.

Kijo-Kleczkowska, Agnieszka

2012-10-01

182

Fluidized-bed-combustor modeling  

Microsoft Academic Search

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 SOâ by limestone in the bed. The model is

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

1977-01-01

183

Combustion in fluidized beds  

SciTech Connect

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

Dry, F.J.; La Nauze, R.D. (CSIRO, Div. of Mineral and Process Engineering, Clayton, Victoria 3168 (AU))

1990-07-01

184

Emissions of NO x and N 2O during co-combustion of dried sewage sludge with coal in a bubbling fluidized bed combustor  

Microsoft Academic Search

Emissions of NOx and N2O were measured during mono-combustion of dried sewage sludge and co-combustion with coal in a bench-scale bubbling fluidized bed combustor. After starting the sludge feed, emissions of NOx increased with time, but N2O emissions changed only slightly. After a certain amount of sludge was burned, the fuel was switched from sludge to coal. Emissions of NOx

Tadaaki Shimizu; Masanori Toyono; Hajime Ohsawa

2007-01-01

185

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  

Microsoft Academic Search

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

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

2008-01-01

186

Effect of temperature on reduction of CaSO oxygen carrier in chemical-looping combustion of simulated coal gas in a fluidized bed reactor  

Microsoft Academic Search

Chemical-looping combustion (CLC) is a promising combustion technology for gaseous and solid fuel with efficient use of energy and inherent separation of CO. The concept of a coal-fueled CLC system using, calcium sulfate (CaSO) as oxygen carrier is proposed in this study. Reduction tests of CaSO oxygen carrier with simulated coal gas were performed in a laboratory-scale fluidized bed reactor

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

2008-01-01

187

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

SciTech Connect

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.

Not Available

1991-01-31

188

Utility boiler design\\/cost comparison: fluidized-bed combustion vs. flue gas desulfurization. Final report, August 1975March 1977  

Microsoft Academic Search

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 (AFB), and pressurized fluidized-bed combustion\\/combined cycle (PFB). The AFB and PFB designs\\/estimates used were completed by the General Electric Co. as part of the Energy

Reese

1977-01-01

189

Fluidized bed combustor modeling  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

190

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

SciTech Connect

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

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

1999-07-01

191

Pilot-scale fluidized-bed combustor testing cofiring animal-tissue biomass with coal as a carcass disposal option  

SciTech Connect

This study was performed to demonstrate the technical viability of cofiring animal-tissue biomass (ATB) in a coal-fired fluidized-bed combustor (FBC) as an option for disposing of specified risk materials (SRMs) and carcasses. The purpose of this study was to assess the technical issues of feeding/combusting ATB and not to investigate prion deactivation/pathogen destruction. Overall, the project successfully demonstrated that carcasses and SRMs can be cofired with coal in a bubbling FBC. Feeding ATB into the FBC did, however, present several challenges. Specifically, handling/feeding issues resulting from the small scale of the equipment and the extremely heterogeneous nature of the ATB were encountered during the testing. Feeder modifications and an overbed firing system were necessary. Through statistical analysis, it was shown that the ATB feed location had a greater effect on CO emissions, which were used as an indication of combustion performance, than the fuel type due to the feeding difficulties. Baseline coal tests and tests cofiring ATB into the bed were statistically indistinguishable. Fuel feeding issues would not be expected at the full scale since full-scale units routinely handle low-quality fuels. In a full-scale unit, the disproportionate ratio of feed line size to unit diameter would be eliminated thereby eliminating feed slugging. Also, the ATB would either be injected into the bed, thereby ensuring uniform mixing and complete combustion, or be injected directly above the bed with overfire air ports used to ensure complete combustion. Therefore, it is anticipated that a demonstration at the full scale, which is the next activity in demonstrating this concept, should be successful. As the statistical analysis shows, emissions cofiring ATB with coal would be expected to be similar to that when firing coal only. 14 refs., 5 figs., 6 tabs.

Bruce G. Miller; Sharon Falcone Miller; Elizabeth M. Fedorowicz; David W. Harlan; Linda A. Detwiler; Michelle L. Rossman [Pennsylvania State University, University Park, PA (United States). Energy Institute

2006-10-15

192

Computer modeling of fluidized-beds  

SciTech Connect

Bubbling fluidized-bed combustors are being built as a means of burning high-sulfur coals in an environmentally acceptable manner. Although this technology has reached a commercial status, understanding of solids motion and its effect on erosion of heat exchanger tubes immersed in fluidized beds remains inadequate. To understand the mechanics of solids motion in fluidized beds with internal heat exchangers, a two-dimensional fluidized bed is simulated using hydrodynamic models. Predicted instantaneous and time-averaged porosities at different locations in the bed are compared with experimentally measured values. Power spectral analyses of both computed and experimental transient porosities are made to validate the presently used hydrodynamic model of fluidization. This study further extends the validation of such models used in earlier studies to compare experimental and predicted bubble sizes.

Bouillard, J.X.; Lyczkowski, R.W.; Ding, J.

1992-11-01

193

Computer modeling of fluidized-beds  

SciTech Connect

Bubbling fluidized-bed combustors are being built as a means of burning high-sulfur coals in an environmentally acceptable manner. Although this technology has reached a commercial status, understanding of solids motion and its effect on erosion of heat exchanger tubes immersed in fluidized beds remains inadequate. To understand the mechanics of solids motion in fluidized beds with internal heat exchangers, a two-dimensional fluidized bed is simulated using hydrodynamic models. Predicted instantaneous and time-averaged porosities at different locations in the bed are compared with experimentally measured values. Power spectral analyses of both computed and experimental transient porosities are made to validate the presently used hydrodynamic model of fluidization. This study further extends the validation of such models used in earlier studies to compare experimental and predicted bubble sizes.

Bouillard, J.X.; Lyczkowski, R.W.; Ding, J.

1992-01-01

194

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

PubMed

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

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

2009-08-15

195

New approach to understanding NO emission during bubbling fluidized bed coal combustion: separation of NO formation and reduction processes in the bed  

SciTech Connect

A new approach for separately evaluating NO formation and NO reduction during coal combustion in a fluidized bed was investigated. Sixteen different coals were burned in a laboratory-scale bubbling fluidized bed combustor with three different char loadings, which were established by changing the inlet oxygen concentrations. NO conversion ratios (X{sub NO} = the ratio of the mass of N atoms in the emitted NO to the mass of N atoms in the coal) were determined for the coals, and then 'ultimate NO conversion ratios' (X{sub NO}*) were obtained by extrapolation of the lines describing the dependence of X{sub NO} on O{sub 2} consumption rate to an O{sub 2} consumption rate of zero. The X{sub NO}* values correspond to the values that would be obtained for a single coal particle burning in the absence of char particles. Using this technique, the contribution of char particles to NO reduction was evaluated. The X{sub NO}* values depended on the N content and the O/N molar ratio of the coals. The bed temperature dependences of the sensitivity values (the slopes of the lines describing the dependence of X{sub NO} on O{sub 2} consumption rate), which include the contribution of NO reduction by char particles, differed substantially for the different coals. However, char loading had no clear effect on N{sub 2}O emission. This result suggests that the reduction by the char particles involves the competitive reaction of NO and N{sub 2}O, and the effect of the N{sub 2}O reduction by burning char particles was less than NO reduction. Our results indicate the importance of taking into account the effects of NO reduction by char particles on overall NOx emissions during fluidized bed combustion of coal. 19 refs., 14 figs., 2 tabs.

Takahiro Murakami; Yoshizo Suzuki [National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki (Japan)

2009-04-15

196

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

SciTech Connect

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).

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

2003-11-24

197

Fluidized bed calciner apparatus  

DOEpatents

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.

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

1988-01-01

198

Fluidized bed combustor and tube construction therefor  

DOEpatents

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.

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

1981-01-01

199

Tube construction for fluidized bed combustor  

DOEpatents

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.

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

1984-01-01

200

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...

201

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 ...

202

Construction and performance of highway soil subgrades modified with atmospheric fluidized bed conbustion residue and multicone kiln dust. Interim reseach report  

Microsoft Academic Search

In an effort to increase the utilization of by-product materials in highway construction projects, the Kentucky Transportation Cabinet authorized the experimental use of residue from an atmospheric fluidized bed combustion (AFBC) process and multicone kiln dust (MKD), a by-product resulting from the production of lime, as subgrade soil modifiers. The report presents information relative to preconstruction and post-construction laboratory evaluations,

D. Q. Hunsucker; T. C. Hopkins; T. L. Beckham; R. C. Graves

1993-01-01

203

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

SciTech Connect

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.

Mastellone, Maria Laura, E-mail: mlaura.mastellone@unina2.it [Department of Environmental Sciences-Second University of Naples, Via Vivaldi, 43 81100 Caserta (Italy); Zaccariello, Lucio; Santoro, Donato; Arena, Umberto [Department of Environmental Sciences-Second University of Naples, Via Vivaldi, 43 81100 Caserta (Italy)

2012-04-15

204

Some implications of co-combustion of biomass and coal in a fluidized bed boiler  

Microsoft Academic Search

Laboratory combustion experiments were conducted to clarify some implications of co-firing coal with hog fuel and sludge in a power boiler. Combustion tests in a fixed bed stainless steel reactor at four temperatures (675, 725, 775, and 825 °C) under conditions simulating different moisture contents of hog-sludge blends indicated no problems with ignition. Burn-out of the coal reached 88–99%. However,

K Laursen; J. R Grace

2002-01-01

205

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

SciTech Connect

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.

Feihu Li; Jianping Zhai; Xiaoru Fu; Guanghong Sheng [Nanjing University, Nanjing (China). State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment

2006-08-15

206

Determination of the emissions of pollutants formed during the co-combustion of sludges with coals in a fluidized bed combustor  

SciTech Connect

Co-combustion studies were carried out with mixtures of sludges with South African coal using a bubbling fluidized bed combustor of 90 kW. The combustion gases leaving the combustor was analyzed for CO{sub 2}, CO, O{sub 2}, NO{sub x}, N{sub 2}O, and SO{sub 2}. Sorbents were used to reduce the levels of SO{sub 2} and the influence of sorbent in capturing heavy metals during the combustion. Particles were collected from the combustion gases using an isokinetic sampling probe and the solids recovered were then analyzed to determine the particle size range and the composition.

Gulyurtlu, I.; Lopes, H.; Bordalo, C.; Seica, A.; Cabrita, I. [Inst. Nacional de Engenharia e Tecnologia Industrial, Lisboa (Portugal). Dept. de Tecnologias de Combustao

1996-12-31

207

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

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

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

2008-12-15

208

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

SciTech Connect

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.

Songgeng Li; Shuang Deng; Andy Wu; Wei-ping Pan [Western Kentucky University, Bowling Green, KY (United States). Institute for Combustion Science and Environmental Technology

2008-07-15

209

Some developments in the feeding of coal to fluidized bed combustors  

NASA Technical Reports Server (NTRS)

Research is being done in the development of fluid bed combustors for high sulphur coal, using limestone or dolomite in the bed for removal of the sulphur. Operating units to date have proven the inadequacies of available material handling techniques for introduction and control of the coal and adsorbent to the beds. Larger units now being contemplated will pose formidable problems in this area. Some of the techniques which were developed for the existing pilot units and novel ideas under consideration for future, large production units are illustrated and described.

Caldwell, L. G.

1977-01-01

210

A model of a bubbling fluidized bed combustor oriented to char mass estimation  

Microsoft Academic Search

Fluidized bed techniques are employed in coal combustion power plants, because they allow for the use of low-quality fuel and result in low pollutant emissions. The most important dynamical difference between fluidized beds and normal combustion chambers, is that the former are characterized by a significant loading of carbon, usually absent in conventional plants. Fluidized beds are remarkably difficult to

Sergio Bittanti; Paolo Bolzern; M. C. Campi; A. De Marco; G. Poncia; W. Prandoni

2000-01-01

211

Heat transfer to small horizontal cylinders immersed in a fluidized bed  

Microsoft Academic Search

Heat transfer to horizontal cylinders immersed in fluidized beds has been extensively studied, but mainly in the context of heat transfer to boiler tubes in coal-fired beds. As a result, most correlations in the literature have been derived for cylinders of 25-50 mm diameter in vigorously fluidizing beds. In recent years, fluidized bed heat treating furnaces fired by natural gas

J. Friedman; P. Koundakjian; D. Naylor; D. Rosero

2006-01-01

212

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

SciTech Connect

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.

Afacan, O.; Gogebakan, Y.; Selcuk, N. [Middle East Technical University, Ankara (Turkey). Dept. of Chemical Engineering

2007-01-15

213

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

NASA Technical Reports Server (NTRS)

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.

Patch, R. W.

1979-01-01

214

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

SciTech Connect

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.

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

215

Staged fluidized bed  

DOEpatents

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.

Mallon, R.G.

1983-05-13

216

Cold modeling of fluidized-bed combustors. Final report  

Microsoft Academic Search

This research project is intended to provide an understanding of the behavior and detailed information useful for the design of atmospheric fluidized combustors. Fluidized beds operated at room temperature are used to simulate the behavior of hot fluidized bed combustors, and are instrumented to provide detailed information about bubble movement, solids mixing, bed-to-tube heat transfer, gas flow and mixing and

1980-01-01

217

Hydrodynamics of fluidized beds using image analysis  

NASA Astrophysics Data System (ADS)

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.

Hull, Ashley Samuel

218

Particle withdrawal from fluidized bed systems  

DOEpatents

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

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

1982-01-01

219

Steam Gasification of Low Rank Fuel - Biomass, Coal, and Sludge Mixture in A Small Scale Fluidized Bed  

Microsoft Academic Search

The steam gasification of low rank fuels has been carried out in a fluidized bed of 0.02 m i.d. and 0.6 m height to study their product gas composition as an additional gaseous fuel for boiler application. The highest content of hydrogen and carbon monoxide were observed at 900 C and at partial pressure of steam of 0.95 atm within

K. H. Ji; B. H. Song; Y. J. Kim; B. S. Kim; W. Yang; Y. T. Choi; S. D. Kim

220

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

SciTech Connect

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)

Not Available

1992-02-01

221

Studies in an atmospheric bubbling fluidized-bed combustor of 10 MW power plant based on rice husk  

Microsoft Academic Search

In this paper an experience, environmental assessment, a model for exit gas composition, agglomeration problem and a model for solid population balance of 10MW power plant at Jalkheri, Distt. Fatehgarh Sahib, Punjab, India based on rice husk has been discussed. Three phase multistage mathematical model for exit gas composition of rice husk in fluidized bed has been derived. The model

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

2008-01-01

222

An assessment of waste fuel burning in operating circulating fluidized bed boilers  

SciTech Connect

Fluidized bed combustion (FBC), today's fastest growing boiler technology, has the flexibility to burn a wide range of fuels, including many waste fuels, while satisfying all present and anticipated environmental regulations. The first generation of FBC--atmospheric fluidized bed combustion (AFBC)--concentrated on ''bubbling'' fluidized bed designs. These systems have inherent limitations and experienced several problems. In response to these problems, circulating fluidized bed (CFB) technology was developed.

Gendreau, R.J.; Raymond, D.L.

1986-01-01

223

An assessment of waste fuel burning in operating circulating fluidized bed boilers  

Microsoft Academic Search

Fluidized bed combustion (FBC), today's fastest growing boiler technology, has the flexibility to burn a wide range of fuels, including many waste fuels, while satisfying all present and anticipated environmental regulations. The first generation of FBC--atmospheric fluidized bed combustion (AFBC)--concentrated on ''bubbling'' fluidized bed designs. These systems have inherent limitations and experienced several problems. In response to these problems, circulating

R. J. Gendreau; D. L. Raymond

1986-01-01

224

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

SciTech Connect

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.

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

1992-09-01

225

Apparatus for controlling fluidized beds  

DOEpatents

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.

Rehmat, Amirali G. (Westmont, IL); Patel, Jitendra G. (Bolingbrook, IL)

1987-05-12

226

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

SciTech Connect

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.

NONE

1995-07-31

227

Gas phase hydrodynamics inside a circulating fluidized bed  

E-print Network

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

Moran, James C. (James Christopher)

2001-01-01

228

Construction and performance of highway soil subgrades modified with atmospheric fluidized bed conbustion residue and multicone kiln dust. Interim reseach report  

SciTech Connect

In an effort to increase the utilization of by-product materials in highway construction projects, the Kentucky Transportation Cabinet authorized the experimental use of residue from an atmospheric fluidized bed combustion (AFBC) process and multicone kiln dust (MKD), a by-product resulting from the production of lime, as subgrade soil modifiers. The report presents information relative to preconstruction and post-construction laboratory evaluations, construction procedures, construction monitoring activities, and performance evaluations of a highway subgrade soil modified using AFBC spent lime, MKD, Type 1P cement, and hydrated lime. An untreated section served as a control for the project located on Kentucky Route 11 in Lee and Wolfe Counties.

Hunsucker, D.Q.; Hopkins, T.C.; Beckham, T.L.; Graves, R.C.

1993-01-01

229

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

SciTech Connect

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.

NONE

1995-12-31

230

Scaling of pressurized fluidized beds  

SciTech Connect

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.

Guralnik, S.; Glicksman, L.R.

1994-10-01

231

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

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.

Yan Cao; Hongcang Zhou; Junjie Fan; Houyin Zhao; Tuo Zhou; Pauline Hack; Chia-Chun Chan; Jian-Chang Liou; Wei-ping Pan [Western Kentucky University (WKU), Bowling Green, KY (USA). Institute for Combustion Science and Environmental Technology (ICSET)

2008-12-15

232

Fluidized-bed filter for particulate cleanup  

SciTech Connect

Successful development of advanced coal-fired power conversion systems often requires reliable and efficient gas-stream-cleanup devices that can remove particulate and gaseous pollutants from high temperature and high pressure gas streams. A novel filter concept for particulate cleanup has been developed at the Morgantown Energy Technology Center (METC). The filter consists of a fine screened surface immersed in a fluidized bed of granular material. As the gas stream passes through the fluidized bed, a layer of fine granular material is deposited and packed at the screen surface, which provides a natural filter to separate the fine particles from the gas stream. Since the filtering media is the granular material supplied by the fluidized bed, the filter is not subjected to blinding. Cleaning the filter (if necessary) is much easier than with a ceramic filter because the inflowing gas, not the cohesive forces, maintains the filter media at the screen surface. Therefore, the screensurface can be readily cleaned by momentarily interrupting the gas flow. A two-dimensional fluidized-bed filter cold model was designed, constructed, and operated to explore the feasibility of this novel concept.

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

1992-01-01

233

Tenth annual fluidized bed conference  

SciTech Connect

The proceedings of the Tenth Annual Fluidized Bed Conference is presented. The Conference was held November 14-15, 1994 in Jacksonville, FL and covered such topics as: opportunity fuels, the fluid bed market, bubbling fluid bed retrofitting, waste fuel-based circulating fluidized-bed project, construction permits for major air pollution sources, fluidized bed residues, uses for fluidized bed combustion ash, ash pelletization, sorbents for FBC applications, refractory maintenance, and petroleum coke. A separate abstract and indexing have been prepared for each paper for inclusion in the Energy Science and Technology Database.

NONE

1994-12-31

234

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

SciTech Connect

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.

None

1987-07-31

235

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

SciTech Connect

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.

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

1980-10-01

236

Control of acid gases using a fluidized bed adsorber.  

PubMed

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

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

2003-08-01

237

Fast fluidized bed steam generator  

DOEpatents

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.

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

1980-01-01

238

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

NASA Astrophysics Data System (ADS)

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.

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

239

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

PubMed

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

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

2013-01-01

240

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

PubMed

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

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

2009-05-01

241

Northern States Power Company (NSP) Black Dog generating plant - Unit 2 emission reduction, capacity increase and life extension through atmospheric fluidized bed combustion (AFBC) retrofit  

SciTech Connect

The authors report on progress to date of the atmospheric fluidized-bed combustion (AFBC) boiler retrofit at the Black Dog Unit 2 plant of the Northern States Power Company. Construction began in September 1984 after the completion of technical and economic feasibility studies, and initial operation is scheduled for the second quarter of 1986. The project features the largest AFBC boiler to date, a 40 MW capacity regain/upgrade, and 25-year extension of unit life, low leakage regenerative air preheater design, electrostatic precipitator performance improvement, alternate fuel co-firing capacity, and reduced emission on a per MW basis. The authors describe the management and engineering developments associated with the project. 12 figures, 4 tables.

Jenness, B.L.; Rosendahl, S.M.; Gamble, R.L.

1985-08-01

242

Development of fluidized bed cement sintering technology  

SciTech Connect

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.

Mukai, Katsuji [Sumitomo Cement Co., Ltd. (Japan)

1994-12-31

243

An innovative vibration fluidized bed ash cooler  

SciTech Connect

With the ever-increasing versatility, scaling up and commercialization of coal-fired fluidized bed boiler technologies, it has become more and more important to improve the technique of draining bed ash from bubbling or circulating fluidized bed boilers. Choosing an ash cooler is a good way but highly stable and reliable system is hard to find for a massive ash flow rate having a broad particle size distributions. An innovative technique known as Vibration Fluidized Bed Ash Cooler (VFBAC) is proposed in this paper. It can drain bottom ash at a high temperature from FB or CFB boilers continuously and controllably. In this device, air used for cooling can be used as combustion-aided air or coal spreading air. The hot ash is cooled by the air to a temperature which it can be transported easily and safely by conventional technology. Meanwhile, an industrial apparatus utilizing the new technology was manufactured and used in a 35 t/h bubbling FB boiler. For the purpose of detecting residence time distribution of wide-sieved bed materials in this ash cooler systematically, advantage was taken of a new approach for physical quality discrimination. Investigations into the hydrodynamic characteristics of the gas-solid two-phase flows and theoretical analyses on hot operational performance were carried out. The results show that heat recovery efficiency of the ash cooler reaches 85% greater when operating at a ratio of air to ash of 1.5{approximately}2.5 Nm{sup 3}/kg.

Duan, Y.; Zhang, M.; Liu, A.; Yao, Z.; Tang, H.; Liu, Q.

1999-07-01

244

Rivesville multicell fluidized bed boiler  

SciTech Connect

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.

Not Available

1981-03-01

245

Coal-fired gas turbine for locomotive propulsion  

SciTech Connect

Substitution of a deeply-cleaned coal-water slurry fuel for bulk solid coal in an atmospheric fluidized-bed combustor permits a sequence of evolutionary steps which can convert the conventional AFBC into a pressurized, combustion-stirred, fluidized-bed heat exchanger compact enough to propel a standard locomotive by use of a closed Brayton power cycle.

Green, L. Jr.

1987-01-01

246

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

SciTech Connect

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.

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

1980-10-01

247

Multifuel bubbling bed fluidized bed combustor system  

SciTech Connect

Apparatus for generating heat is described, comprising: a fluidized bed pyrolyzer; a fluidized bed combustor; a combustor vessel; means for supporting a combustor bed of granular material within the combustor vessel; means for adding the gaseous effluents removed from the pyrolyzer bed to the combustor bed; means for adding granular material to the combustor bed; means for removing gaseous effluents from the combustor vessel; means for removing bed material from the combustor; a heat exchanger comprising a vessel; means for adding gaseous effluents to, and means for removing gaseous effluents from, the heat exchanger vessel, and means for adding an exchange coolant to, and means for removing an exchange coolant from, the heat exchanger vessel; particulate collector means connected to the heat exchanger for removing particulate matter from the gaseous effluents removed from the heat exchanger; and stack means connected to the particulate collector for releasing the gaseous effluents removed from the heat exchanger to the atmosphere.

Wormer, A.F.

1989-04-25

248

Fluidized-bed filtration for particulate cleanup  

SciTech Connect

Successful development of advanced coal-fired power conversion systems often requires reliable and efficient gas stream-cleanup devices that can remove particulate and gaseous pollutants from high-temperature and high-pressure gas streams. A novel filter concept for particulate cleanup has been developed at the Morgantown Energy Technology Center (METC). The filter consists of a fine screened surface immersed in a fluidized bed of granular material. As the gas stream passes through the fluidized bed, a layer of fine granular material is deposited and packed at the screen surface, which provides a natural filter to separate the fine particles from the gas stream. Since the filtering media is the granular material supplied by the fluidized bed, the filter is not subjected to blinding. Cleaning the filter (if necessary) is much easier than with a ceramic filter because the inflowing gas, not the cohesive forces, maintains the filter media at the screen surface. Therefore, the screen surface can be readily cleaned by momentarily interrupting the gas flow. A two-dimensional fluidized-bed filter cold model was designed, constructed, and operated to explore the feasibility of this novel concept. The two-dimensional, transparent unit allowed clear observation of the general fluidized state of the granular material and the conditions under which fines are captured by the particle layer. A series of parametric tests was conducted to provide acceptable operating conditions for the model configuration. Preliminary results are presented in this paper. Effects of various parameters, such as superficial gas velocity, bed depth, particle size, and distance from the filter to the gas distributor, on filter behavior are characterized through differential pressure and differential pressure fluctuation data.

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

1993-01-01

249

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

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.

Das, M.; Meikap, B.C.; Saha, R.K. [Indian Institute for Technology, Kharagpur (India). Dept. for Chemical Engineering

2008-06-15

250

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

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.

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

1980-09-01

251

Particle pressures in fluidized beds  

SciTech Connect

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.

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

1992-01-01

252

Advanced modeling of nitrogen oxide emissions in circulating fluidized bed combustors: Parametric study of coal combustion and nitrogen compound chemistries  

SciTech Connect

This paper describes work-in-progress aimed at developing an emission model for circulating fluidized bed combustors using detailed homogeneous and heterogeneous chemical kinetics. The main emphasis is on nitrogen oxides (NO{sub x}, N{sub 2}O) but also unburned gases (CO, C{sub x}H{sub y}) and sulfur dioxide (SO{sub 2}) will be investigated in the long run. The hydrodynamics is described by a 1.5-dimensional model where the riser is divided into three regions: a dense bubbling bed at the bottom, a vigorously mixed splash zone, and a transport zone. The two latter zones are horizontally split into a core region and an annular region. The solids circulation rate is calculated from the known solids inventory and the pressure and mass balances over the entire circulation loop. The solids are divided into classes according to size and type or particle. The model assumes instantaneous fuel devolatilization at the bottom and an even distribution of volatiles in the suspension phase of the dense bed. For addition of secondary air, a complete penetration and an instantaneous mixing with the combustor gases in the core region is assumed. The temperature distribution is assumed to be known, and no energy balance is solved. A comprehensive kinetic scheme of about 300 elementary gas-phase reactions is used to describe the homogeneous oxidation of the volatiles including both hydrocarbon and volatile-nitrogen components (NH{sub 3}, HCN). Heterogeneous char combustion to CO and CO{sub 2}, and char-nitrogen conversion to NO, N{sub 2}O, and N{sub 2} are described by a single particle model that includes 15 reaction steps given in the form of 6 net reaction paths. In the paper, the model is briefly described. A special emphasis is put on the evaluation of chemistry submodels. Modeling results on nitrogen oxides' formation are compared with measured concentration profiles in a 12 MW CFBC riser from literature. The importance of accurate chemistry description on predictions is illustrated by comparing modeling results using detailed kinetics to those obtained when hydrocarbon and volatile-nitrogen oxidation are described with empirical, global kinetic rate expressions from literature. Submodels that need further improvements are discussed.

Kilpinen, P.; Kallio, S.; Hupa, M.

1999-07-01

253

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

SciTech Connect

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.

None

1982-10-21

254

Particle injection and mixing experiments in a one-quarter scale model bubbling fluidized bed  

Microsoft Academic Search

One significant factor in the operation of a fluidized bed combustor is the manner in which coal particles disperse and mix with the bed material upon entering the bed. A thermal tracing technique was used to study the mixing characteristics in a 1\\/4 scale model of a pressurized bubbling fluidized bed combustor. Particles cooled by liquid nitrogen are injected into

Leon Glicksman; Ezra Carr; Peter Noymer

2008-01-01

255

Bubble Characterization in Pressurized Fluidized-Bed Combustors with Bed Internals  

Microsoft Academic Search

Bubble Characterization in Pressurized Fluidized-Bed Combustors with Bed Internals Abstract–Bubble characteristics within a tube bundle of a Pressurized Fluidized Bed Coal Combustor (PFBC) were studied. A model was developed to compute emulsion phase gas velocity, bubble throughflow velocity, and the visible bubble flow coefficient. Experimental data obtained from a PFBC unit were compared with the model prediction and a good

K. M. Sellakumar; V. Zakkay

1988-01-01

256

A dynamic model of the hydrodynamics of a liquid fluidized bed  

Microsoft Academic Search

The efficient design, operation, and scale up of novel fluidized bed bioreactors for direct coal liquefaction require detailed knowledge of reactor axial pressure drop, dispersion of the solid and liquid phases, and the particle size distribution as a function of axial position. In this paper, a fully predictive mathematical description of the hydrodynamics of a liquid fluidized bed, containing no

Mohammad Asif; James N. Petersen; Eric N. Kaufman; John M. Cosgrove; Timothy C. Scott

1994-01-01

257

Fluidized bed boiler waste as a source of nutrients and lime  

Microsoft Academic Search

Fluidized bed boilers for steam electric power plants have been developed recently to improve efficiency and to utilize coal and a wide range of other fuels. The fluidized bed waste (FBW) generated by these boilers is expected to reach large volumes as new plants are built. It is an anhydrous waste containing substantial amounts of CaSOâ and unreacted CaO. Since

G. L. Terman; V. J. Kilmer; C. M. Hunt; W. Buchanan

1978-01-01

258

Pressurized fluidized-bed combustion  

SciTech Connect

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)

Not Available

1980-10-01

259

Refractory experience in circulating fluidized bed combustors, Task 7  

SciTech Connect

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.

Vincent, R.Q.

1989-11-01

260

Pressurized fluidized bed reactor  

DOEpatents

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.

Isaksson, J.

1996-03-19

261

Pressurized fluidized bed reactor  

DOEpatents

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.

Isaksson, Juhani (Karhula, FI)

1996-01-01

262

Second-Generation Pressurized Fluidized Bed Combustion: Small gas turbine industrial plant study  

SciTech Connect

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.

Shenker, J.; Garland, R.; Horazak, D.; Seifert, F.; Wenglarz, R.

1992-07-01

263

Second-Generation Pressurized Fluidized Bed Combustion: Small gas turbine induustrial plant study  

SciTech Connect

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.

Shenker, J.; Garland, R.; Horazak, D.; Seifert, F.; Wenglarz, R.

1992-07-01

264

Economics of co-firing waste materials in an advanced pressurized fluidized-bed combustor  

SciTech Connect

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 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 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. 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.

Bonk, D.L.; McDaniel, H.M. [Dept. of Energy, Morgantown, WV (United States). Morgantown Energy Technology Center; DeLallo, M.R. Jr.; Zaharchuk, R. [Gilbert/Commonwealth, Inc., Reading, PA (United States)

1995-04-01

265

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

SciTech Connect

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.

Zevenhoven, R.; Skrifvars, B.J.; Hupa, M. [Aabo Akademi Univ., Turku/Aabo (Finland). Dept. of Chemical Engineering; Frankenhaeuser, M. [Borealis Polymers oy, Porvoo (Finland)

1998-12-31

266

Ninth annual fluidized bed conference  

SciTech Connect

Ten papers were presented at the Ninth Fluidized Bed Conference held in Bakersfield, CA on December 7-8, 1993. The papers covered such subjects as community relations, operational experience at the NISCO cogeneration facility, multiple stoker-field retrofit with fluidized bed combustion, influence of fuel properties, combustion of pulp and papermill sludges and biomass in bubbling fluidized boilers, diesel emissions control reactor power cycle, erosion-corrosion resistant coatings in CFBC systems, FBC's role in solid fuel firing, and the role for solid fuel firing in the Nation's energy future. A separate abstract was prepared for each paper for the Energy Data Base.

Not Available

1993-01-01

267

Fluidized-bed combustion apparatus  

SciTech Connect

A fluidized bed shell boiler for producing steam or hot water or a fluidized bed hot gas generator or incinerator in which the position at which bed material is deposited downstream of the bed is controlled. A baffle of firebrick with gas-flow passages extending through the baffle is positioned in the tube downstream of the bed. Gas velocities are distributed across the tube so that bed material is preferentially deposited in the combustion chamber downstream of the furnace tube. Deposition in the furnace tube is reduced to zero or to a negligible amount and deposition downstream of the combustion chamber is reduced.

Brealey, L.; Demircan, N.; Wilson, J.H.

1984-03-06

268

Comminution of limestone during batch fluidized-bed calcination and sulfation  

Microsoft Academic Search

Batchwise fluidized-bed calcination and sulfation of a limestone were done to investigate particle comminution phenomena and their relation with parallel occurrence of reactions. Operating conditions of the bed were those typical of atmospheric bubbling fluidized-bed combustors. A general framework of comminution phenomena is outlined, which includes different types of fragmentations as well as attrition by abrasion. Comminution processes were characterized

Fabrizio Scala; Antonio Cammarota; Riccardo Chirone; Piero Salatino

1997-01-01

269

Modeling of a fluidized bed combustor with immersed tubes  

Microsoft Academic Search

Progress is reported in the development of a mathematical model of a fluidized-bed combustor. The model will include coal combustion phenomena and will incorporate basic mass transport relationships, bubble mechanics, heat transfer and configuration effects. A cold model test bed will be designed, constructed and operated to generate data in support of the effort in developing the mathematical model. In

S. C. Saxena; N. S. Grewal

1977-01-01

270

Peach and apricot stone combustion in a bubbling fluidized bed  

Microsoft Academic Search

In this study, a bubbling fluidized bed combustor (BFBC) of 102 mm inside diameter and 900 mm height was used to investigate the combustion characteristics of peach and apricot stones produced as a waste from the fruit juice industry. A lignite coal was also burned in the same combustor. The combustion characteristics of the wastes were compared with that of

Burçak Kaynak; Hüseyin Topal; Aysel T. Atimtay

2005-01-01

271

APPLICATION OF FLUIDIZED-BED TECHNOLOGY TO INDUSTRIAL BOILERS  

EPA Science Inventory

The report gives results of a paper study of the application potential of coalfired fluidized-bed boilers (FBB's) in the industrial use sector. It considers: the ability of coal-fired FBB's to meet the requirements of industrial users, including cost, reliability, maintainability...

272

DMEC-1 Pressurized Circulating Fluidized-Bed Demonstration Project  

SciTech Connect

The DMEC-1 project will demonstrate the use of Pyropower`s PYROFLOW pressurized circulating fluidized bed technology to repower an existing coal fired generating station. This will be the first commercial application of this technology in the world. The project is now in budget period 1, the preliminary design phase.

Kruempel, G.E.; Ambrose, S.J. [Midwest Power, Des Moines, IA (United States); Provol, S.J. [Pyropower Corp., San Diego, CA (United States)

1992-12-01

273

Apparatus and process for controlling fluidized beds  

DOEpatents

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.

Rehmat, Amirali G. (Westmont, IL); Patel, Jitendra G. (Bolingbrook, IL)

1985-10-01

274

Partial gasification of coal in a fluidized bed reactor: Comparison of a laboratory and pilot scale reactors  

Microsoft Academic Search

A 0.1 MWth lab-scale and 2 MWth pilot-scale experimental rigs were constructed to demonstrate the technical feasibility of a new process. The aim of the\\u000a lab-scale study is to optimize coal partial gasification reactions operating conditions, which were applied in the pilot-scale\\u000a tests. A comparison between the laboratory and pilot scale experimental results is presented in this paper in order

Rui Xiao; Laihong Shen; Mingyao Zhang; Baosheng Jin; Yuanquan Xiong; Yufeng Duan; Zhaoping Zhong; Hongcang Zhou; Xiaoping Chen; Yaji Huang

2007-01-01

275

Measurement techniques in fluidized beds  

Microsoft Academic Search

Quantities that need to be measured in gas fluidized-bed systems include solids volume concentrations, solids velocities and solids mass flows, the vertical and horizontal distribution of solids inside the system, the lateral distribution of the fluidizing gas, temperatures and gas concentrations. In the present paper an overview is given on available measuring techniques. In the first section techniques for industrial

Joachim Werther

1999-01-01

276

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....

277

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...

278

CHARACTERIZATION OF SOLID RESIDUES FROM FLUIDIZED-BED COMBUSTION UNITS  

EPA Science Inventory

The report gives results of physical and chemical characterizations of samples of spent bed material and of flyash from three experimental atmospheric and pressurized fluidized-bed combustion (FBC) units. It also gives results of characterization of samples of bed material which ...

279

Fluidized bed desulfurization  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

280

Development of a Simulation Model for Fluidized Bed Mild Gasifier  

Microsoft Academic Search

A mild gasification method has been developed to provide an innovative clean coal technology. The objective of this study is to developed a numerical model to investigate the thermal-flow and gasification process inside a specially designed fluidized-bed mild gasifier using the commercial CFD solver ANSYS\\/FLUENT. Eulerain-Eulerian method is employed to calculate both the primary phase (air) and secondary phase (coal

AKM Monayem Hossain Mazumder

2010-01-01

281

The effect of solid concentration on the secondary air-jetting penetration in a bubbling fluidized bed  

Microsoft Academic Search

The introduction of secondary air (SA) in fluidized bed boilers is of important engineering significance. In the present work, an experimental study on the characteristics of SA penetration is carried out by operating a bubbling fluidized bed model. Floater, the ash formed from coal combustion, is used as experimental bed material. It has an average size of 0.83 mm and a

Jihui Chen; Xiaofeng Lu; Hanzhou Liu; Jia Liu

2008-01-01

282

Advanced Fluidized Bed Waste Heat Recovery Systems  

E-print Network

ADVANCED FLUIDIZED BED WASTE HEAT RECOVERY SYSTEMS G. R. PETERSON Project Manager U.S. Department of Energy, Idaho Operations Office Idaho Falls, Idaho ABSTRACT The U.S. Department of Energy, Office of Industri al Programs, has sponsored... the development of a Fluidized Bed Waste Heat Recovery System (FBWHRS) and a higher temperature variant, the Ceramic Tubular Distributor Plate (CTOP) Fluidized Bed Heat Exchanger (FBHX) system. Both systems recover energy from high-temperature flue gases...

Peterson, G. R.

283

Agglomeration-Free Distributor for Fluidized Beds  

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

284

Fundamentals of fluidized bed chemical processes  

SciTech Connect

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.

Yates, J.G.

1983-01-01

285

Mixing and reaction in the circulating fluidized bed – A three-dimensional combustor model  

Microsoft Academic Search

Horizontal gas and solids mixing processes may play a dominant role in circulating fluidized bed (CFB) reactors with a small height-to-diameter ratio, which is typical for CFB combustors. A semi-empirical approach was chosen to describe the threedimensional combustion of coal in a circulating fluidized bed with a rectangular cross section. Since the combustion process is rather complex, the underlying gas–solid

T. Knoebig; K. Luecke; J. Werther

1999-01-01

286

EFFECT OF RECYCLE ON FLUIDIZED-BED COMBUSTION AND EMISSION CHARACTERISTICS OF HIGH-SULFUR LIGNITE  

Microsoft Academic Search

The effect of recycle on gaseous pollutant emissions from fluidized-bed combustion of high-quality coals has extensively been investigated and is well documented. However, the effect of recycle on gaseous emissions from combustion of Turkish lignites with high ash, volatile matter, and sulfur contents has not been investigated to date. Recent trends in the utilization of indigenous lignites in fluidized-bed boilers

Nevin Selçuk; Yusuf Gogebakan; Hakan Harmandar; Hakan Altindag

2004-01-01

287

Fluidized bed deposition of diamond  

DOEpatents

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.

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

1998-01-01

288

Staged cascade fluidized bed combustor  

DOEpatents

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.

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

1984-01-01

289

Multifuel bubbling bed fluidized bed combustor system  

Microsoft Academic Search

Apparatus for generating heat is described, comprising: a fluidized bed pyrolyzer; a fluidized bed combustor; a combustor vessel; means for supporting a combustor bed of granular material within the combustor vessel; means for adding the gaseous effluents removed from the pyrolyzer bed to the combustor bed; means for adding granular material to the combustor bed; means for removing gaseous effluents

Wormer

1989-01-01

290

Four Rivers second generation Pressurized Circulating Fluidized Bed Combustion Project  

SciTech Connect

Air Products has been selected in the DOE Clean Coal Technology Round V program to build, own, and operate the first commercial power plant using second generation Pressurized Circulating Fluidized Bed (PCFB) combustion technology. The four Rivers Energy Project (Four Rivers) will produce up to 400,000 lb/hr steam, or an equivalent gross capacity of 95 MWe. The unit will be used to repower an Air Products chemicals manufacturing facility in Calvert City, Kentucky.

Holley, E.P.; Lewnard, J.J. [Air Products and Chemicals, Inc. (United States); von Wedel, G. [LLB Lurgi Lentjes Babcock Energietechnik (GmbH); Richardson, K.W. [Foster Wheeler Energy Corp. (United States); Morehead, H.T. [Westinghouse Electric Corp. (United States)

1995-04-01

291

Enhanced durability of desulfurization sorbents for fluidized-bed applications  

Microsoft Academic Search

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

R. P. Gupta; S. K. Gangwal

1991-01-01

292

Continuous austempering fluidized bed furnace. Final report  

SciTech Connect

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.

Srinivasan, M.N. [Lamar Univ., Beaumont, TX (United States). Dept. of Mechanical Engineering] [Lamar Univ., Beaumont, TX (United States). Dept. of Mechanical Engineering

1997-09-23

293

Flue gas desulfurization under simulated oxyfiring fluidized bed combustion conditions: The influence of limestone attrition and fragmentation  

Microsoft Academic Search

Flue gas desulfurization by means of limestone injection under simulated fluidized bed oxyfiring conditions was investigated, with a particular focus on particle attrition and fragmentation phenomena. An experimental protocol was applied, based on the use of complementary techniques that had been previously developed for the characterization of attrition of sorbents in air-blown atmospheric fluidized bed combustors. The extent and pattern

Fabrizio Scala; Piero Salatino

2010-01-01

294

Solid fuel feed system for a fluidized bed  

DOEpatents

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.

Jones, Brian C. (Windsor, CT)

1982-01-01

295

Heat transfer in horizontal tubes immersed in fluidized beds  

NASA Astrophysics Data System (ADS)

A theoretical model is proposed, and experimental data presented and analyzed, for the overall convective heat transfer coefficient at ambient conditions between horizontally immersed tubes and a gas fluidized bed of particle sizes usually applicable in fluidized bed combustion of coal. The overall heat transfer coefficient is a function of gas and particle heat transfer coefficients. The bubbling flow assumption, together with the two phase theory of fluidization, is used to obtain a simple analytical solution for the particle convective heat transfer coefficient. The equation for gas convective heat transfer coefficient is obtained through an analogy with heat transfer in packed beds. To a first order approximation the particle and gas convective components are additive.

Anekwe, C. I.

296

Enhanced durability of desulfurization sorbents for fluidized-bed applications  

SciTech Connect

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.

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

1991-06-01

297

Heat and mass transfer in fixed and fluidized beds  

SciTech Connect

This book includes papers reviewing the fundamentals of heat and mass transfer and features studies on special processes in packed and fluidized beds, new application areas, and special orientation regimes. The topics presented cover: fluid particle transfer in packed beds; heat transfer in fixed submerged surfaces in fluidized beds; fundamentals and measurements and applications; heat and mass transfer to suspended objects in fluidized beds; modeling of fluidized bed reactors; fluidized bed combustion and gasification; special fluidized bed processes; liquid and three-phase fluidization; packed bed reactor; and special operations in fluidized beds.

Van Swaaij, W.P.M.; Afgan, N.H.

1985-01-01

298

A model for volatiles release into a bubbling fluidized-bed combustor  

Microsoft Academic Search

A volatiles release model has been developed to predict the location and quantity of coal volatiles that are released into a bubbling fluidized-bed combustor, using overbed, in-bed or underbed feed systems. This model not only considers time resolution of the simultaneous processes of coal devolatilization and coal particle movement after injection, but also takes account of the stochastic nature of

John F. Stubington; Shu W. Chan; Stephen J. Clough

1990-01-01

299

Fluidized bed heat treating system  

DOEpatents

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.

Ripley, Edward B; Pfennigwerth, Glenn L

2014-05-06

300

Circulating Fluidized Bed Combustion Boiler Project  

E-print Network

The project to build a PYROFLOW circulating fluidized bed combustion (FBC) boiler at the BFGoodrich Chemical Plant at Henry, Illinois, is described. This project is being partially funded by Illinois to demonstrate the feasibility of utilizing high...

Farbstein, S. B.; Moreland, T.

1984-01-01

301

Fluidized bed heating process and apparatus  

NASA Technical Reports Server (NTRS)

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.

McHale, Edward J. (Inventor)

1981-01-01

302

Gasification in Fluidized Beds — Present Status & Design  

NASA Astrophysics Data System (ADS)

Biomass has made great in-roads in its use in energy and chemical industries. Gasification is one of the major means for its conversion. For thermo-chemical conversion of biomass three major gas-solid contacting processes, fixed bed, entrained bed and fluidized bed are used. Various versions of fixed bed gasifier (up-draft, down-draft, and side-draft) proved successful but primarily in small capacity units while entrained bed reactors found favour in very large capacity units. Fluidized bed gasifier fills the important intermediate size range. A review of the current commercial use of fluidized bed gasifier shows that it is yet to take the centre stage in the gasification market. This paper examines the issues preventing wider scale use of fluidized bed gasifier and what is the current state of research in those issues.

Basu, Prabir; Acharya, Bishnu; Dutra, Animesh

303

State of Fluidized Bed Combustion Technology  

E-print Network

are discussed. Potential application of fluidized bed boilers in industrial plants using lignite and lignite refuse is examined. The impact of proposed new DOE and EPA regulations on solid fuels burning is also examined....

Pope, M.

1979-01-01

304

Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1995--March 31, 1995  

SciTech Connect

Experiments performed support the hypothesis that a reducing atmosphere during fluidized bed coal combustion contributes to the formation of agglomerates. Reducing conditions are imposed by controlling the amount of combustion air supplied to the combustor, 50% of theoretical in these experiments. These localized reducing conditions may arise from either poor lateral bed mixing or oxygen-starved conditions due to the coal feed locations. Deviations from steady-state operating conditions in bed pressure drop may be used to detect agglomerate formation. Interpretation of the bed pressure drop was made more straightforward by employing a moving average difference method. During steady-state operation, the difference between the moving point averages should be close to zero, within {plus_minus}0.03 inches of water. Instability within the combustor, experienced once agglomerates begin to form, can be recognized as larger deviations from zero, on the magnitude of {plus_minus}0.15 inches of water.

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

1995-04-01

305

Comparative results of multifuels fluidized bed combustion testing in both bubbling and circulating bed modes  

Microsoft Academic Search

GA Technologies Inc. has completed more than 7500 hr of fluidized bed combustion research on a wide variety of fuels, including bituminous coal and coal refuse, petroleum coke, and radioactive and industrial wastes. These tests have been sponsored by United States and foreign government agencies; electric utilities, a number of industrial firms, including chemical, oil, and primary metals companies; and

Rickman

1984-01-01

306

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

SciTech Connect

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.

Vincent, R.Q.

1989-11-01

307

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

SciTech Connect

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.

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

1980-10-01

308

Use of simplified scaling laws to examine hydrodynamics of pressurized circulating fluidized beds  

SciTech Connect

Laboratory-scale cold fluidized beds have been used extensively to study fluidized bed hydrodynamics. Previously, it has been shown that laboratory-scale cold models can be used to simulate the hydrodynamics of a hot fluidized bed combustor when a set of dimensionless scaling laws is matched between the two beds. These scaling laws have been verified by numerous researchers in both atmospheric bubbling and atmospheric circulating fluidized beds. A recent study at the Massachusetts Institute of Technology (MIT) demonstrated that it is possible to relax some of the scaling relationships, producing a simplified set of scaling laws. The advantage of the simplified set of scaling parameters over the full set is the increased flexibility in the design of a model to simulate a combustor or chemical reactor. With the full set of scaling parameters, a scale model fluidized bed with air at ambient conditions is constrained to a single set of operating and geometric conditions. A cold model of an atmospheric combustor has linear dimensions approximately one-quarter those of the combustor. A cold model of a pressurized combustor has linear dimensions which are 20% larger than those of the combustor. Use of the simplified set of parameters allows the cold model to have much smaller linear dimensions than the combustor. In the present study, the simplified set of scaling laws are applied to a Foster Wheeler 33 cm diameter, 11.5 m high circulating fluidized bed combustor pressurized to 7.5 bar. A 1/6.5 scale model of the hot pressurized circulating fluidized bed, constructed and operated by Foster Wheeler Development Corp., has been constructed. Recently completed validation tests included comparisons of the vertical solids distribution along with the probability density functions and power spectral densities of the pressure fluctuations within the beds. The data suggest good agreement when the simplified scaling parameters are held constant between the hot combustor and cold model.

Hyre, M.R.; Glicksman, L.R. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Torpey, M. [Foster Wheeler Development Corp., Livingston, NJ (United States)

1997-12-31

309

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

SciTech Connect

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.

Not Available

1980-08-01

310

Scaling of pressurized fluidized beds: Quarterly report, July--September 1994  

SciTech Connect

Laboratory-scale cold fluidized beds have been used extensively to study fluidized-bed hydrodynamics. Cold models have the advantage that they permit detailed room temperature investigations, such as determining the effects of varying operating parameters and bed design on the hydrodynamics, to be performed in a rapid and cost-effective manner. However, in order for the results of these investigations to be relevant to commercial fluidized bed combustors, the cold model must be properly scaled to simulate hot-bed hydrodynamics. Previously, it has been shown that laboratory-scale cold models can be used to simulate the hydrodynamics of a hot fluidized bed combustor when a set of dimensionless scaling laws is matched between the two beds. These scaling laws have been verified by numerous researchers in both atmospheric bubbling and circulating fluidized beds. A recent study at MIT, on atmospheric circulating beds, demonstrated that it was possible to relax some of the scaling relationships, producing a simplified set of scaling laws which allows the model to be much smaller than the combustor. In the current study, the simplified scaling laws are applied to pressurized bubbling fluidized beds. A quarter-scale cold model of American Electric Power`s (AEP) Tidd 70 MW{sub e} pressurized fluidized bed combustor (PFBC) has been constructed. The scale model has been used to establish the validity of the simplified scaling laws for pressurized bubbling beds. Scaling verifications include comparisons of the probability density functions of the pressure fluctuations in the Tidd PFBC and the cold model. A comparison of the average solid-fraction profiles is also presented.

Not Available

1994-10-01

311

NO x formation and selective non-catalytic reduction (SNCR) in a fluidized bed combustor of biomass  

Microsoft Academic Search

Caledonian Paper (CaPa) is a major paper mill, located in Ayr, Scotland. For its steam supply, it previously relied on the use of a Circulating Fluidized Bed Combustor (CFBC) of 58 MWth, burning coal, wood bark and wastewater treatment sludge.It currently uses a bubbling fluidized bed combustor (BFBC) of 102 MWth to generate steam at 99 bar, superheated to 465 °C. The boiler is

Shiva Mahmoudi; Jan Baeyens; Jonathan P. K. Seville

2010-01-01

312

Wear prediction in a fluidized bed  

SciTech Connect

A procedure to model the wear of surfaces exposed to a fluidized bed is formulated. A stochastic methodology adapting the kinetic theory of gases to granular flows is used to develop an impact wear model. This uses a single-particle wear model to account for impact wear from all possible-particle collisions. An adaptation of a single-particle abrasion model to describe the effects of many abrading particles is used to account for abrasive wear. Parameters describing granular flow within the fluidized bed, necessary for evaluation of the wear expressions, are determined by numerical solution of the fluidized bed hydrodynamic equations. Additional parameters, describing the contact between fluidized particles and the wearing surface, are determined by optimization based on wear measurements. The modeling procedure was used to analyze several bubbling and turbulent fluidized bed experiments with single-tube and tube bundle configurations. Quantitative agreement between the measured and predicted wear rates was found, with some exceptions for local wear predictions. This work demonstrates a methodology for wear predictions in fluidized beds.

Boyle, E.J. [USDOE Morgantown Energy Technology Center, WV (United States); Rogers, W.A. [EG and G Washington Analytical Services Center, Inc., Morgantown, WV (United States)

1993-06-01

313

Fluidized bed charcoal particle production system  

SciTech Connect

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.

Sowards, N.K.

1985-04-09

314

Pressurized circulating fluidized-bed combustion for power generation  

SciTech Connect

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.

Weimer, R.F.

1995-08-01

315

Advanced controls - fuzzy logic for fluidized bed boiler  

Microsoft Academic Search

Fluidized bed combustion is a good technology for burning wet and varying fuels with low flue gas emissions and high efficiency. A supervisory level control applica- tion constantly controls CFB (Circulating Fluidized Bed) or BFB (Bubbling Fluidized Bed) combustion to minimize flue gas emissions (NOx (nitrogen oxides), SO2 (sulfur dioxide), and CO (carbon monoxide)), improve combustion efficiency, and reduce use

Tero Joronen; Rupert Kerschbaum

316

Experimental Analysis of Fuel Mixing Patterns in a Fluidized Bed  

Microsoft Academic Search

The mixing pattern of a tracer particle which simulates a fuel particle is studied in a cold 2-dimensional fluidized bed with respect to the influence of fluidization velocity, bed height, tracer particle size and air-distributor pressure drop under conditions typical for bubbling fluidized bed boilers as well as the bottom region of circulating fluidized bed boilers. The results show that

David Pallarčs; Pedro A. Díez; Filip Johnsson

2007-01-01

317

Scale-up of bubbling fluidized bed reactors — A review  

Microsoft Academic Search

The scale-up of bubbling fluidized bed reactors to commercial size is a complex and troublesome endeavor. In particular, the proper scale-up of the hydrodynamics and chemical conversion inside the fluidized bed is subject to many eventualities and pitfalls which may drastically deteriorate the reactor's performance and economy. The main challenge of fluidized bed scaling is the scale dependence of many

Tilman J. Schildhauer; Serge M. A. Biollaz; J. Ruud van Ommen

318

Reduction of particulate carryover from a pressurized fluidized bed  

NASA Technical Reports Server (NTRS)

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

Patch, R. W.

1979-01-01

319

Dynamic model of a fluidized bed dryer  

SciTech Connect

An axially distributed dynamic model of a gas-solid continuous fluidized bed dryer is developed. The steady state form of the model is compared with the existing models. Through simulation profiles of the moisture content and temperature of the bed are obtained. The transient analysis of the developed model is studied with reference to step changes in the air inlet temperature, superficial air velocity, particle residence time, initial moisture content of the feed and dryer-wall temperature. The results are useful in developing precise control strategies to implement on the fluidized bed dryer.

Panda, R.C.; Ramachandra Rao, V.S. (Indian Inst. of Tech., Madras (India))

1993-01-01

320

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

SciTech Connect

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.

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

2005-01-30

321

Hydrodynamic performance of a novel design of pressurized fluidized bed combustor  

Microsoft Academic Search

A bench-scale fluidized bed combustor with a novel fluidizing gas injection manifold was successfully built for characterization of Australian black coals under PFBC conditions. Instead of the usual horizontal distributor plate to support the bed and distribute the fluidizing gas, the fluidizing gas was injected horizontally through 8 radial ports in the cylindrical wall of the combustor: To verifiy satisfactory

Alan L. T. Wang; John F. Stubington; Jiangang Xu

2006-01-01

322

Modeling of a fluidized bed combustor with immersed tubes. Quarterly report, September--November 1975  

Microsoft Academic Search

A mathematical model of a fluidized bed combustor is being developed which will include coal combustion phenomena and will incorporate basic mass transport relationships, bubble mechanics, heat transfer and configuration effects. A cold model test bed will be designed, constructed and operated to generate data in support of the effort in developing the mathematical model. In particular, experiments will provide

S. C. Saxena; A. Rehmat; N. S. Grewal; T. P. Chen

1975-01-01

323

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...

324

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,...

325

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...

326

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

SciTech Connect

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.

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

327

Scaling of pressurized fluidized beds. First quarterly progress report, October 1, 1992--January 15, 1993  

SciTech Connect

Some preliminary work has been done to develop potential cold scale model designs to simulate the bed hydrodynamics of the American Electric Power Tidd pressurized bubbling fluidized bed combustor. The first design is based on the full set of scaling parameters presented in Equation (1), the second design was developed using the simplified set of scaling parameters given in Equation (2). The first design is roughly a 1:1 representation of a section of the core of the Tidd bed combustor. The additional flexibility provided by the simplified set of scaling parameters is particularly useful for developing experimental models of pressurized fluidized bed combustors where the full set of scaling relationships does not provide any reduction in the size of the models. Both the full and the simplified set of scaling relationships have been verified for applications to circulating fluidized bed combustors operating at atmospheric pressure. Currently there is a interest in fluidized bed combustors which operate at elevated pressures ({approximately}12 atm) for combined-cycle applications. One of the primary goals of this stud r is to verify both the till set and the simplified set of scaling relationships for applications to pressurized bubbling fluidized bed combustors.

Glicksman, L.; Farrell, P.

1993-09-01

328

Polypropylene Combustion in a Fluidized Bed Combustor  

Microsoft Academic Search

Waste plastics show a great promise in energy recovery via combustion process due to the high calorific value and the implementation of policies to improve recycling. The output of waste plastics is especially relatively enormous. In this work, energy recycle from waste plastics was investigated in a semi-pilot scale fluidized bed combustor. The waste plastic selected in this work was

J. Han; T. Shimizu; M. Wataru; H. Kim; G. Wang

2010-01-01

329

Predictive models for circulating fluidized bed combustors  

Microsoft Academic Search

The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. The Appendix to this report presents our three dimensional computer code which we developed in last few months. It generalizes the two dimensional version of our code FLUFIX used at Argonne National Laboratory. We tested this code by comparing the computations to

Gidaspow

1990-01-01

330

Fluidized Bed Combustion for Clean Energy  

Microsoft Academic Search

This paper gives a brief overview of the status and prospects for fluidized bed combustion (FBC) for clean energy, with focus on power and heat generation. The paper summarizes recent development trends for the FB technology and makes an outlook into the future with respect to challenges and opportunities for the technology. The paper also identifies areas related to fluidization,

Filip Johnsson

2007-01-01

331

FBC: Gaining acceptance. [Fluidized Bed Combustion  

SciTech Connect

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.

Gawlicki, S.M.

1991-04-01

332

Fluidization quality analyzer for fluidized beds  

DOEpatents

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.

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

1995-01-01

333

Particle Pressures in Fluidized Beds. Final report  

SciTech Connect

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.

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

1996-09-01

334

Particle pressures in fluidized beds. Final report  

SciTech Connect

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.

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

1996-09-01

335

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...

336

Reversed flow fluidized-bed combustion apparatus  

DOEpatents

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.

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

1984-01-01

337

Fluidized bed combustion of alternative solid fuels  

Microsoft Academic Search

The fluidized bed combustion of a number of alternative fuels of practical interest has been analyzed by a combination of experimental and modeling techniques. Solid fuels of widely different origin (biomass, agricultural, civil and industrial wastes) have been considered in this work. A lab-scale experimental campaign was carried out to evaluate the comminution (fragmentation, attrition) behavior of the fuels. Experimental

Fabrizio Scala; Riccardo Chirone

2004-01-01

338

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

SciTech Connect

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.

Brown, R.C.

1988-12-01

339

Modeling carbonizing process in fluidized bed  

NASA Astrophysics Data System (ADS)

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.

Szota, M.; Jasinski, J.

2010-06-01

340

Spectral methods applied to fluidized-bed combustors  

SciTech Connect

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

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

1995-11-01

341

Simultaneous reduction of emissions of SO{sub 2}, NOx, and N{sub 2}O from fluidized bed combustors  

SciTech Connect

The effects of staged air feed and limestone feed into a bubbling fluidized bed combustor on emissions of SO{sub 2}, NOx and N{sub 2}O were investigated. The staged air feed reduced both NOx and N{sub 2}O emissions, but it inhibited SO{sub 2} removal. NOx emission increased with increasing sulfur removal. To solve the interference problem among reduction of NOx, N{sub 2}O, and SO{sub 2}, a two-staged fluidized bed combustor was proposed, in which combustion of coal was conducted in the lower bed and SO{sub 2} capture in the upper bed. To simulate two-staged FBC, flue gas from a circulating fluidized bed combustor was fed into a fluidized bed reactor of limestone. NOx emission did not increase with SO{sub 2} capture and more effective decrease in N{sub 2}O emission was achieved for the two-staged fluidized bed combustion in comparison to the conventional in-situ SO{sub 2} capture. The results of SO{sub 2} capture and N{sub 2}O reduction for two-staged fluidized bed were analyzed using the Junii-Levenspiel model. A fixed bed reactor was employed to obtain kinetic data. The results of the calculations agreed fairly well with the experimental results.

Shimizu, Tadaaki; Miura, Masashi; Togashi, Takeshi; Tonsho, Masaru; Inagaki, Makoto [Niigata Univ., Ikarashi, Niigata (Japan). Dept. of Chemistry and Chemical Engineering; Matsukata, Masahiko [Osaka Univ., Machikaneyama, Toyonaka (Japan). Dept. of Chemical Engineering

1995-12-31

342

Effect of experimental conditions on co-gasification of coal, biomass and plastics wastes with air\\/steam mixtures in a fluidized bed system  

Microsoft Academic Search

The effect of temperature and of gasification medium was studied, using only air, only steam and mixtures of both as gasification medium, with the aim of optimising co-gasification of coal and wastes. The rise in gasification temperature promoted hydrocarbons further reactions, leading to a decrease in tars and hydrocarbons contents and an increase in H2 release. Increasing temperature, from 750

Filomena Pinto; Carlos Franco; Rui Neto André; C. Tavares; M. Dias; I. Gulyurtlu; I. Cabrita

2003-01-01

343

Heat transfer in pressurized circulating fluidized beds  

SciTech Connect

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.

Wirth, K.E. [Univ. Erlangen-Nuernberg, Erlangen (Germany). Lehrstuhl fuer Mechanische Verfahrenstechnik

1997-12-31

344

Dynamic Simulation of Fluidized Bed Combustors and its Validation Against Measurements  

Microsoft Academic Search

A dynamic mathematical model of a continuous atmospheric bubbling fluidized bed combustor (ABFBC) has been developed on the basis of first principles and used to correlate data from a pilot-scale combustor. The model accounts for bed and freeboard hydrodynamics, volatiles release and combustion, char particles combustion and their size distribution, and heat transfer. The solution procedure of dynamic model employs

NEVIN SELÇUK; ENGIN DEGIRMENCI

2001-01-01

345

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

Microsoft Academic Search

In this study, cofiring of high ash and sulfur content lignite with hazelnut shell and cotton residue was investigated in 0.3 MWt METU Atmospheric Bubbling Fluidized Bed Combustion (ABFBC) Test Rig in terms of combustion and emission performance of different fuel blends. The results reveal that cofiring of hazelnut shell and cotton residue with lignite increases the combustion efficiency and

Zuhal Gogebakan; Nevin Selcuk

2008-01-01

346

A model of the dynamics of a fluidized bed combustor burning biomass  

Microsoft Academic Search

A dynamical model of an atmospheric, bubbling, fluidized bed combustor of biomass is presented. The model, based on one previously developed for the steady combustion of high-volatile solids, accounts for the fragmentation and attrition of fuel particles, the segregation and postcombustion of volatile matter above the bed, as well as thermal feedback from the splashing region to the bed. The

Antonio Galgano; Piero Salatino; Silvestro Crescitelli; Fabrizio Scala; Pier Luca Maffettone

2005-01-01

347

Fragmentation of wood char in a laboratory scale fluidized bed combustor  

Microsoft Academic Search

Casuarina equisetifolia, a hard wood, and a popular energy crop in many tropical countries, was investigated experimentally for its char fragmentation in a laboratory scale atmospheric bubbling fluidized bed combustor. The effect of fuel shape and size on wood char fragmentation was studied. Wood particles of spherical, cylindrical (aspect ratio of 1), and cubical shapes of different sizes ranging from

D. Ruben Sudhakar; K. Srinivas Reddy; Ajit Kumar Kolar; Bo Leckner

2008-01-01

348

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...

349

Two-dimensional simulation of temperature distributions inside pressurized fluidized bed combustors  

SciTech Connect

A particular characteristic of Pressurized Fluidized Bed Combustors with stationary fluidized beds (PFBC) is the high rate of heat release in the vicinity of he coal feed points. This may cause local overheating of the bed. Thus a two-dimensional model is presented which describes the temperature distribution inside a PFBC as a function of coal characteristics, operating parameters and geometry. The model is composed of two mass balances describing the carbon and the oxygen concentration inside the stationary bed as well as of an enthalpy balance. Furthermore, a submodel takes into account the feed of coal into the reactor as a coal-water mixture. The numerical calculations yield two-dimensional profiles of the carbon and the oxygen concentration and the temperature distribution, respectively. The simulation results point at and quantify critical parameters which have to be considered when dealing with the scale-up of boilers from the pilot-scale to large-scale size.

Artlich, S.; Mackens, W.; Werther, J. [Technical Univ. Hamburg-Harburg, Hamburg (Germany)

1997-12-31

350

Emissions During Co-Firing of RDF5 with Coal in a 22 t\\/h Steam Bubbling Fluidized Bed Boiler  

Microsoft Academic Search

\\u000a The co-firing of biomass and fossil fuel in the same power plant is one of the most important issues when promoting the utilization\\u000a of renewable energy in the world. Recently, the co-firing of coal together with biomass fuel, such as “densified refuse derived\\u000a fuel” (d-RDF or RDF-5) or RPF (refuse paper & plastic fuel) from waste, has been considered as

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

2010-01-01

351

Bed material agglomeration during fluidized bed combustion  

SciTech Connect

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.

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

1993-02-01

352

Control of a Circulating Fluidized Bed  

SciTech Connect

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.

Shim, Hoowang; Rickards, Gretchen; Famouri, Parviz; Turton, Richard (WVU); Sams, W. Neal (EG& G); Koduro, Praveen; Patankar, Amol; Davari, Assad (WVUIT); Lawson, Larry; Boyle, Edward J. (DOE)

2001-11-06

353

Solar heated fluidized bed gasification system  

NASA Technical Reports Server (NTRS)

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.

Qader, S. A. (inventor)

1981-01-01

354

Use of glow discharge in fluidized beds  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

355

Reactor for fluidized bed silane decomposition  

NASA Technical Reports Server (NTRS)

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.

Iya, Sridhar K. (Inventor)

1989-01-01

356

Fluidized bed combustion of municipal solid waste  

SciTech Connect

Energy recovery from municipal solid waste (MSW) is an important component of an integrated waste management strategy. Waste management programs which remove or recover materials for recycling are particularly suited for considering the option of energy recovery via fluidized bed combustion (FBC). The last few years have seen growing interest in the application of FBC technology to the MSW treatment/disposal problem. This paper reviews and reports on the world-wide experience in fluidized bed combustion of MSW focusing particularly on the types and scales of the systems in operation in Japan and Scandinavia. In addition the paper also reports on the development of an energy from waste project employing circulating fluidized bed technology that is proposed for a local municipality in the UK. Japan currently has over 100 bubbling bed units in operation firing on 100% MSW; the technology is firmly established at scales of operation up to 160,000t/y (the largest single unit operates at 6.25t/h). The bubbling bed units accept MSW which has undergone only minimal pre-processing -- the waste is shredded to a nominal 300mm size fraction before being introduced to the furnace. There are distinct (combustion control) advantages to further processing of the waste stream prior to combustion. The Scandinavian countries in particular have been the prime movers in pioneering this technology to work in combination with circulating fluidized bed systems. Currently 2 units are in operation cofiring pre-processed MSW with a range of other biofuels. A number of FBC units firing 100% MSW are currently in the planning or construction stage around the world; they seem set to secure an increased market share particularly at the smaller scale of operation (up to about 200,000t/y).

Wheeler, P.A.; Patel, N.M. [Energy Technology Support Unit, Harwell (United Kingdom); Painter, A. [Kvaerner Enviropower Ltd., London (United Kingdom)

1995-12-31

357

Biomass gasification in a circulating fluidized bed  

Microsoft Academic Search

This paper presents the results from biomass gasification tests in a pilot-scale (6.5-m tall × 0.1-m diameter) air-blown circulating fluidized bed gasifier, and compares them with model predictions. The operating temperature was maintained in the range 700–850°C, while the sawdust feed rate varied from 16 to 45kg\\/h. Temperature, air ratio, suspension density, fly ash re-injection and steam injection were found

X. T. Li; J. R. Grace; C. J. Lim; A. P. Watkinson; H. P. Chen; J. R. Kim

2004-01-01

358

Predicting apparent Sherwood numbers for fluidized beds  

SciTech Connect

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.

Groenewold, H.; Tsotsas, E.

1999-09-01

359

Fluidized bed gasification of agricultural residue  

E-print Network

and complete ash removal by entrainment. The most prominent difficulty encountered during operation was the performance of the solid feed system. Solid feed was augered to a junction where an air stream transported the solid reactants into the reactor... and Kinetics Development of Gasification Systems Fixed Bed Gasifiers Fluidized Bed Gasifiers Fluidization 6 7 12 12 13 16 III DEVELOPMENT OF EXPERIMENTAL SYSTEM . . . 20 IV Feed Preparation and Analysis Experimental Apparatus Experimental Method...

Groves, John David

1979-01-01

360

Cluster Dynamics in a Circulating Fluidized Bed  

SciTech Connect

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.

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

2006-11-01

361

Zone heating for fluidized bed silane pyrolysis  

NASA Technical Reports Server (NTRS)

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.

Iya, Sridhar K. (Inventor)

1987-01-01

362

Status of the fluidized bed unit  

SciTech Connect

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.

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

1994-06-01

363

Single-stage fluidized-bed gasification  

NASA Astrophysics Data System (ADS)

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.

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

1982-04-01

364

Experimental study and modelling of char combustion under fluidized bed conditions  

NASA Astrophysics Data System (ADS)

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

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

1998-12-01

365

High-temperature sulphur removal under fluidized bed combustion conditions — A chemical interpretation  

Microsoft Academic Search

Theoretical and experimental studies were conducted on coal sulphur removal under chaotically changing oxidizing and reducing conditions, which occur in the dense zone of bubbling fluidized beds. Experimental desulphurization trends were analyzed by comparison with multi-species (50 gas-phase, 7 solid-phase species) equilibrium calculations for coal\\/steam\\/sorbent\\/air system. It was shown, that under fluctuating reducing\\/oxidizing conditions, sulphur capture as CaS in locally

S. V. Makarytchev; K. F. Cen; Z. Y. Luo; X. T. Li

1995-01-01

366

AGGLOMERATION BEHAVIOR IN A BUBBLING FLUIDIZED BED AT HIGH TEMPERATURE  

Microsoft Academic Search

Minimum fluidization velocity and agglomeration behavior were investigated at high temperature in an 80?×?30?mm two-dimensional quartz fluidized bed and in an 82?mm i.d. circular fluidized bed. Bed materials tested were two sizes of glass beads as well as three sizes of fluidized bed combustor (FBC) ash. The minimum fluidization velocity decreased with increasing bed temperature, whereas the minimum sintering fluidization

QINGJIE GUO; TOSHIYUKI SUDA; Juni'Chi Sato; GUANGXI YUE

2004-01-01

367

Pressure Fluctuations as a Diagnostic Tool for Fluidized Beds  

Microsoft Academic Search

The purpose of this project was to investigate the origin of pressure fluctuations in;\\u000afluidized bed systems. The study assessed the potential for using pressure fluctuations as an;\\u000aindicator of fluidized bed hydrodynamics in both laboratory scale cold-models and industrial scale;\\u000aboilers. Both bubbling fluidized beds and circulating fluidized beds were evaluated. Testing;\\u000aincluding both cold-flow models and laboratory and

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

1998-01-01

368

Current Status and Challenges within Fluidized Bed Combustion  

Microsoft Academic Search

Fluidized-bed technology is rapidly expanding. Today, more than 600 large (20+ MWth) FBC boilers with a total installed thermal\\u000a capacity of more than 70,000 MWth have been built. Around 75% of this capacity is circulating fluidized beds (CFBC) technology,\\u000a the rest mostly bubbling fluidized beds (BFBC). The size of the boilers has increased steeply; the largest CFBC units being\\u000a constructed

Mikko Hupa

369

Fluidized-Bed Waste-Heat Recovery System Advances  

E-print Network

FLUIDIZED-BED WASTE-HEAT RECOVERY SYSTEM ADVANCES Keith D. Patch William E. Cole Thermo Electron Corporation Waltham, Massachusetts ABSTRACT The Fluidized-Bed Waste-Heat Recovery (FBWHR) System is a combustion air preheater designed...-to-air heat exchanger surfaces. In the FBWHR system, a recirculating partic ulate medium is heated as it falls through upward flowing flue gases in a raining-bed heat exchanger. This heated medium is passed across a fluidized bed heat exchanger...

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

370

Combustion and mass transfer characteristics of large carbon particles in the grid region of a fluidized-bed combustor  

Microsoft Academic Search

A fluidized-bed coal combustor is a diluted system in which each burning coal particle is surrounded by many inert bed particles due to its low concentration in the bed. These inert particles present a major resistance to oxygen transfer. Most studies on mass transfer have been for the bubbling region; this study characterizes combustion and mass transfer phenomena in the

1988-01-01

371

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

DOEpatents

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.

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

1982-01-01

372

Fluidized Bed Asbestos Sampler Design and Testing  

SciTech Connect

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.

Karen E. Wright; Barry H. O'Brien

2007-12-01

373

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

SciTech Connect

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.

NONE

1995-06-01

374

Technical evaluation: pressurized fluidized-bed combustion technology  

SciTech Connect

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.

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

375

Modeling biomass gasification in circulating fluidized beds  

NASA Astrophysics Data System (ADS)

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

Miao, Qi

376

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

SciTech Connect

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.

Kaeferstein, P.; Tepper, H.; Gohla, M.; Reimer, H. [Otto-von-Guericke-Univ. of Magdeburg (Germany). Dept. Heat Transfer and Energy Economy

1997-12-31

377

Packed fluidized bed blanket for fusion reactor  

DOEpatents

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.

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

1984-01-01

378

Transients in a circulating fluidized bed boiler  

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

379

Combined fluidized bed retort and combustor  

DOEpatents

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

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

1984-01-01

380

Mathematical modeling of fluidized bed reactors  

E-print Network

MULTIPLICITY OF STEADY STATES IN AN ISOTHERMAL FLUIDIZED BED REACTOR II-A. The Davidson and Harrison Model (DHM). II-A-1. DHPM Model with Constant Bubble Size II-A-2. DHPM Model with Variable Bubble Size. II-B. Bubble Growth Correlations '(BGC's) II...) Page 14 18 18 19 21 22 22 III-A-1. III-A-2. DHPM Model with Constant Bubble Size. DHPM Model with Variable Bubble Size, 22 23 III-A-3. III-A-4. DHPF Model with Size. DHPF Model with Size. Constant Bubble Variable Bubble 24 25...

Nasif, Nilufer Havva

1985-01-01

381

Gasification in Fluidized Beds — Present Status & Design  

Microsoft Academic Search

\\u000a Biomass has made great in-roads in its use in energy and chemical industries. Gasification is one of the major means for its\\u000a conversion. For thermo-chemical conversion of biomass three major gas-solid contacting processes, fixed bed, entrained bed\\u000a and fluidized bed are used. Various versions of fixed bed gasifier (up-draft, down-draft, and side-draft) proved successful\\u000a but primarily in small capacity units

Prabir Basu; Bishnu Acharya; Animesh Dutra

2010-01-01

382

State of Industrial Fluidized Bed Combustion  

E-print Network

they will be interesta:1, they rray not have long to wait. Several FBC units are nON in operation. A wide range of boiler designs and capacities are be ing developed and finns such as COmbustion Engineer ing, Foster Wheeler, Jolmston Boiler and Riley Babcock, ani...-1500F) arrl as a re sult of the conbustion of its CO content will be controlled at approximately 845C (1550F) f r cap ture of the S02 content in a fluidized bed'of lime stone. The limestone will capture approximately 95 percent of the SO...

Mesko, J. E.

1982-01-01

383

Pressure Fluctuations as a Diagnostic Tool for Fluidized Beds  

SciTech Connect

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

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

1998-05-01

384

Modeling of fuel mixing in fluidized bed combustors  

Microsoft Academic Search

This paper presents a three-dimensional model for fuel mixing in fluidized bed combustors. The model accounts for mixing patterns which were experimentally shown to govern mixing in risers with geometry and operational conditions representative for furnaces in fluidized bed combustors. The mixing process is modeled for three different solid phases in the furnace and the model, which includes the return

David Pallarčs; Filip Johnsson

2008-01-01

385

Kinetic behavior of solid particles in fluidized beds  

SciTech Connect

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

Kono, H.O.

1990-06-01

386

Fluidized bed cogeneration plant at Midwest Grain Products: the economic edge  

Microsoft Academic Search

A fluidized bed boiler installed at the Midwest Grain Products of Illinois, Pekin plant is described. The 120,000 lb\\/hr bubbling type fluidized boiler was installed in 1983 along with a 3500 kW turbine generation set. The boiler is a single cell, natural circulation design, firing high-sulfur Illinois coal. Cogeneration was added to the slope of the project to improve the

D. A. Toth; L. M. Seaberg

2009-01-01

387

NO sub x and N sub 2 O formation in pressurized fluidized-bed combustion tests  

Microsoft Academic Search

Batch combustion tests have been performed in a small bubbling fluidized-bed reactor with the objective of establishing process variable effects on the formation of NOâ (NO and NOâ) and NâO in the combustion of coals of various rank. The reactor has been operated both in a differential mode with once-through gas flow for the purpose of studying primary production of

P. H. Wallman; E. L. Ivarsson; R. C. J. Carlsson

1990-01-01

388

Research of integral parameters for furnaces of a circulating fluidized bed  

NASA Astrophysics Data System (ADS)

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.

Gil, Andrey V.; Gil, Alexandra Y.

2015-01-01

389

Fluidized bed air-to-air heat pump evaporator evaluation  

NASA Astrophysics Data System (ADS)

Frost formation of air-to-air heat pump evaporator surfaces reduces unit efficiency and restricts application. The use of a fluidized bed heat exchanger as an air-to-heat pump evaporator was investigated to determine if frost accumulation could be eliminated. Experimental investigations were conducted and the following results obtained: (1) frost accumulation was insignificant with fluidized bed temperatures below 32 F and (2) moisture accumulation from condensation resulted in unstable fluidized bed operation when the fluidized bed temperature was above 32 F. Several concepts - maintenance bed temperature below 32 F, reverse refrigerant flow, air-dry bed, nonadhering bed material, and ultrasonics - to solve the moist bed problem were evaluated, with no practical solution being developed. The use of a fluidized bed heat exchanger for air-to-air heat pump evaporators was determined not feasible.

Ashley, J. L.

1983-07-01

390

Modeling of a fluidized bed combustor with immersed tubes. Quarterly report, December--February 1975--76  

Microsoft Academic Search

A mathematical model of a fluidized-bed combustor will be developed which will include coal combustion phenomena and incorporate basic mass transport relationships, bubble mechanics, heat transfer and configuration effects. A cold model test bed will be designed, constructed and operated to generate data in support of the effort in developing the mathematical model. In particular, experiments will provide data concerning

S. C. Saxena; A. Rehmat; N. S. Grewal; T. P. Chen

1976-01-01

391

EFFECT OF EMISSION CONTROL REQUIREMENTS ON FLUIDIZED-BED BOILERS FOR INDUSTRIAL APPLICATIONS: PRELIMINARY TECHNICAL/ECONOMIC ASSESSMENT  

EPA Science Inventory

The report gives results of an assessment of coal-fired industrial fluidized-bed boilers (FBBs) to estimate the impact, on boiler cost and performance, of alternative control levels for SOx, NOx, and particulate emissions. Base industrial FBB conceptual designs are presented, and...

392

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

EPA Science Inventory

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

393

Development of Catalytic Tar Decomposition in an Internally Circulating Fluidized-Bed Gasifier  

NASA Astrophysics Data System (ADS)

Biomass gasification in an Internally Circulating Fluidized-bed Gasifier (ICFG) using Ni/Ah03 as tar cracking catalyst is studied at low temperature. Reaction conditions of the catalyst bed are discussed, including catalytic temperature and steam ratio. High energy efficiency and hydrogen-rich, low-tar product gas can be achieved in a properly designed multi-stage gasification process, together with high-performance catalyst. In addition, considering the economical feasibility, a newly-developed Ni-loaded brown coal char is developed and evaluated as catalyst in a lab-scale fluidized bed gasifier with catalyst fixed bed. The new catalyst shows a good ability and a hopeful prospect oftar decomposition, gas quality improvement and catalytic stability.

Xiao, Xianbin; Le, Due Dung; Morishita, Kayoko; Li, Liuyun; Takarada, Takayuki

394

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

SciTech Connect

The purpose of this report is to summarize the progress made on the project ''Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion (CFBC) System'' in this quarter (September-December of 2003). The main tasks in this quarter consisted of the following four parts. First, all documents for managing this project have been prepared and sent to the Office of Project Management at the US Department of Energy's (DOE's) National Energy Technology Laboratory (NETL). Second, plans for the renovation of space for a new combustion laboratory for the CFBC system has progressed smoothly. Third, considerable progress in the design of the CFBC system has been made. Finally, a lab-scale simulated fluidized-bed combustion facility has been set up in order to make some fundamental investigations of the co-firing of coal with waste materials in the next quarter. Proposed work for the next quarter has been outlined in this report.

Wei-Ping Pan; Kunlei Liu; John T. Riley

2004-01-01

395

Comparative results of multifuels fluidized bed combustion testing in both bubbling and circulating bed modes  

SciTech Connect

GA Technologies Inc. has completed more than 7500 hr of fluidized bed combustion research on a wide variety of fuels, including bituminous coal and coal refuse, petroleum coke, and radioactive and industrial wastes. These tests have been sponsored by United States and foreign government agencies; electric utilities, a number of industrial firms, including chemical, oil, and primary metals companies; and a boiler supplier. Testing has been conducted in GA's 2 mm Btu/hr pilot plant in San Diego, California. This modern facility is operated either as a bubbling fluidized bed combustor or as an advanced circulating bed combustor. It is highly instrumented with a computer-based control and data acquisition system that allows accurate determination of process performance. All tests were structured to determine the most economical operating conditions for maximizing combustion efficiency while minimizing emissions such as SO/sub 2/, CO, NO/sub x/, and HCl. Results to date conclusively indicate inherent advantages to the circulating bed mode of combustion in all of these performance criteria. These advantages are mostly due to the increased turbulence, mixing, recycle, and throughput in the circulating bed as well as to the mechanical difficulties associated with operation of a bubbling fluidized bed.

Rickman, W.S.

1984-01-01

396

Verification of the simplified hydrodynamic scaling parameters for commercial pressurized fluidized bed combustors. Part 1: Bubbling fluidized beds  

SciTech Connect

A recent study at the Massachusetts Institute of Technology (MIT), on atmospheric circulating beds, demonstrated that it was possible to relax some of the scaling relationships, producing a simplified set of scaling laws which allows the model to be much smaller than the combustor. In the present study, the simplified scaling laws are applied to pressurized bubbling fluidized beds. A quarter-scale cold model of American Electric Power`s (AEP) Tidd 70 MW{sub e} pressurized fluidized bed combustor (PFBC) has been constructed. The scale model has been used to establish the validity of the simplified scaling laws for pressurized bubbling beds. Scaling verifications include comparisons of the probability density functions (PDF) of the pressure fluctuations in the Tidd PFBC and the cold model. A comparison of the average solid-fraction profiles is also presented. These comparisons indicate that the hydrodynamics of the cold model are similar to those of the Tidd PFBC. The power spectral densities of the Tidd differential pressure fluctuations, for measurements taken both within the bed and in the freeboard region, contain unexpected peaks at distinct frequencies. A simple analysis was done which compared the peak frequencies in the power spectrum with those of the natural frequencies of a fixed-end beam. This analysis suggested that, possibly, the peaks could be due to an excitation of the natural frequencies of the tube bank. Tidd has not experienced excessive erosion or mechanical failure rates which suggests that any vibration is structurally insignificant. This is corroborated by the excellent agreement obtained in the PDF and solid fraction profile comparisons--the source of the frequency peaks does not appear to have had any significant effect on the bed hydrodynamics.

Glicksman, L.R.; Farrell, P.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Mechanical Engineering

1995-12-31

397

An introduction to the multifuel, circulating fluidized bed boiler  

SciTech Connect

Fluidized bed reactors for chemical application have been used for half a century. In the 1960s and early 1970s, work on fluidized bed combustion was carried out in the U.K. and U.S. At that time all work was devoted to bubbling beds; the prime reason was not the combustion properties but the possibility of desulfurizing in situ. After the oil crisis in 1973 more extensive worldwide work was started by many reputable boiler manufacturers. This paper examines the principles and application of the circulating fluidized bed combustion process.

Kullendorff, A.

1986-01-01

398

Bubbling fluidized bed retrofit with modern design tools  

SciTech Connect

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

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

1999-07-01

399

Fluidized bed boiler having a segmented grate  

DOEpatents

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.

Waryasz, Richard E. (Longmeadow, MA)

1984-01-01

400

Fluidized bed viscosity measurements in reduced gravity  

SciTech Connect

The understanding of fluidized characteristics of solid particles is a major challenge in the prediction of many technological processes in numerous commercial industries including chemical, petroleum, agricultural, pharmaceutical, metallurgical, plastics, and food processing. Fluidized bed viscosity was studied experimentally in a series of reduced gravity parabolic flights aboard NASA`s KC-135 aircraft. Silica sands of two different size distributions were fluidized by air. The experimental set up incorporated instrumentation to measure the air flow rate, the pressure drop and the apparent viscosity of the fluidized sand at the wide range of the shear rate. The fluidization chamber had transparent walls to allow visualization of the structure changes involved in fluidization in reduced gravity. Experiments were performed over a broad range of gravitational accelerations including microgravity and double gravity conditions. The results of the flight and ground experiments reveal significant differences in the apparent viscosity of fluidized sand and overall void factor in microgravity as compared to one-g conditions.

Bakhtiyarov, S.I.; Overfelt, R.A. [Auburn Univ., AL (United States). Space Power Inst.

1997-12-31

401

Wood gasification in a fluidized bed  

NASA Astrophysics Data System (ADS)

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.

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

1980-04-01

402

Advanced control strategies for fluidized bed dryers  

SciTech Connect

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.

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

1999-11-01

403

Fluidized-bed combustion development: Volume 1, Industrial steam generation: Final report  

Microsoft Academic Search

In 1986 Stearns Catalytic performed a study for the US Department of Energy to investigate methodology for improving the economics of atmospheric fluidized bed combustion (AFBC). This report is a result of Phase 1 of this program. The scope of this work involved reviewing the four unit sizes listed: 10,000, 50,000, 100,000, and 200,000 lbs\\/h. The design conditions and plant

B. N. Gaglia; R. L. Claussen

1986-01-01

404

Comparison of experimental and computed solids motion and bed dynamics for fluidized beds containing obstacles  

Microsoft Academic Search

The ensemble- and time-averaged solids velocity field and bed dynamics in the form of pressure oscillations taken in the University of Illinois at Urbana-Champaign's (UIUC) atmospheric thin (3.81 by 40 cm) bubbling fluidized bed which contained a simulated triangular pitch tube array consisting of five round 5.08 cm diameter cylinders are analyzed in this paper using Argonne National Laboratory's hydrodynamic

R. W. Lyczkowski; I. K. Gamwo; F. Dobran; Y. H. Ai; B. T. Chao; M. M. Chen

1991-01-01

405

Investigation of Gas Solid Fluidized Bed Dynamics with Non-Spherical Particles  

SciTech Connect

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.

Choudhuri, Ahsan

2013-06-30

406

21 CFR 890.5160 - Air-fluidized bed.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

407

21 CFR 890.5160 - Air-fluidized bed.  

Code of Federal Regulations, 2011 CFR

...Identification. An air-fluidized bed is a device employing the circulation of filtered air through ceramic spherules (small, round ceramic objects) that is intended for medical purposes to treat or prevent bedsores, to treat severe or...

2011-04-01

408

21 CFR 890.5160 - Air-fluidized bed.  

Code of Federal Regulations, 2012 CFR

...Identification. An air-fluidized bed is a device employing the circulation of filtered air through ceramic spherules (small, round ceramic objects) that is intended for medical purposes to treat or prevent bedsores, to treat severe or...

2012-04-01

409

21 CFR 890.5160 - Air-fluidized bed.  

Code of Federal Regulations, 2014 CFR

...Identification. An air-fluidized bed is a device employing the circulation of filtered air through ceramic spherules (small, round ceramic objects) that is intended for medical purposes to treat or prevent bedsores, to treat severe or...

2014-04-01

410

21 CFR 890.5160 - Air-fluidized bed.  

Code of Federal Regulations, 2013 CFR

...Identification. An air-fluidized bed is a device employing the circulation of filtered air through ceramic spherules (small, round ceramic objects) that is intended for medical purposes to treat or prevent bedsores, to treat severe or...

2013-04-01

411

Model of Fluidized Bed Containing Reacting Solids and Gases  

NASA Technical Reports Server (NTRS)

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.

Bellan, Josette; Lathouwers, Danny

2003-01-01

412

Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1994--March 31, 1994  

SciTech Connect

Laboratory combustion tests conducted this quarter support the hypothesis that localized reducing conditions promote formation of agglomerates in the bed of fluidized bed boilers. These tests were designed to simulate localized reducing conditions found in commercial fluidized bed combustors. Localized reducing conditions may occur from either poor lateral bed mixing or oxygen-starved bed conditions due to the coal feed configuration. It was found-that agglomeration can occur at lower theoretical air values while operating temperatures are within the range of fluidized bed boilers. Cohesion of bed particles appears to take place very rapidly when theoretical air in the bed approaches 70%. These tests also indicate that bed temperature, pressure drop, oxygen and carbon dioxide concentrations are affected by agglomeration. Agglomeration appears to result in: (1) An increase in the frequency of pressure fluctuations (bed pressure drop). (2) An increase in the magnitude of pressure fluctuations (bed pressure drop.) (3) A possible decrease in bed pressure differential over time. In addition, there appears to be an increase in the amount of available oxygen and a decrease in CO{sub 2}. Agglomerates formed in the laboratory are being subjected to mineralogical analyses which will then be compared to similar analyses of agglomerates removed from commercial boilers.

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

1994-04-01

413

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

SciTech Connect

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.

Unknown

2001-07-10

414

Optimum design of capacitance sensor array for imaging the solids distribution of fluidized bed  

SciTech Connect

Fluidized beds are widely used in many industries. Fluidized bed combustion technique is rapidly developed and used to coal-fired power stations in order to improve the combustion efficiency and properties. Measuring the solids distributions of fluidized beds in furnaces are directly related to their working conditions and combustion efficiency, and furthermore are the basis of controlling the beds in the optimum run. Electrical capacitance tomography (ECT) systems recommended in this paper are non-intrusive and inexpensive being developed suitable for imaging density distributions in process pipelines, fluidization processes and so on. Considering that three-dimensional images are required in fluidization processes, several level electrodes are selected as the ECT systems' sensor array, which can provide 3D images by piling up many 2D sectional images. The aim of this paper is to select optimal structure parameters of the sensor array so as to reduce the influence between levels and to improve the properties of the images by use of the numerical tool of finite element method (FEM) and physical phantoms. First, a brief introduction of ECT systems was made and a sensor structure used for visualizing the fuel distributions in fluidized bed combustion was presented. And then, the orthogonal experimental design technique was carried out and a set of optimum sensor structure parameter was given by using fidelity of reconstructed image, spatial image error (SIE), as the optimum objective function. Finally, a comparison was made between two reconstructed images by the optimum structure and a non-optimum structure respectively, the results showed that the image by the non-optimum structure was with errors in gray-level and the SIE = 0 of the image by the optimum structure.

Xu, H.; Yan, H.; Wang, S.

1999-07-01

415

Flow characteristics in a bubbling fluidized bed at elevated temperature  

Microsoft Academic Search

A bubbling fluidized bed with 0.082 m in diameter and 1.5 m in height was employed to investigate the minimum fluidization velocity and flow dynamics at bed temperature up to 1000°C. Ashes of three sizes (Geldart B) from pressurized fluidized bed boiler were used as fluidization materials. Experiments show that the minimum fluidization velocity decreases with increasing bed temperature. Pressure

Qingjie Guo; Guangxi Yue; Toshiyuki Suda; Junichi Sato

2003-01-01

416

An introduction to the multifuel, circulating fluidized bed boiler  

Microsoft Academic Search

Fluidized bed reactors for chemical application have been used for half a century. In the 1960s and early 1970s, work on fluidized bed combustion was carried out in the U.K. and U.S. At that time all work was devoted to bubbling beds; the prime reason was not the combustion properties but the possibility of desulfurizing in situ. After the oil

Kullendorff

1986-01-01

417

Control of bed height in a fluidized bed gasification system  

DOEpatents

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.

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

1983-12-20

418

Fluidized-bed energy technology for biomass conversion  

Microsoft Academic Search

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

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

1982-01-01

419

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 ...

420

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

EPA Science Inventory

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

421

Particle pressures in fluidized beds. First year annual report  

SciTech Connect

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.

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

1992-09-01

422

The influence of calcined limestone on NO x and N 2O emissions from char combustion in fluidized bed combustors  

Microsoft Academic Search

Limestone addition to a coal-fired fluidized bed combustor usually results in an increase in NO\\/NOx emissions and a decrease in N2O emissions. This observation has been explained in the literature by the effect of limestone on: (i) the conversion of coal volatile-N to NO\\/NOx and N2O; (ii) the decomposition of N2O; and (iii) the pool of H, OH and\\/or O

H Liu; B. M Gibbs

2001-01-01

423

High-temperature-staged fluidized-bed combustion (HITS), bench scale experimental test program conducted during 1980. Final report  

Microsoft Academic Search

An experimental program was conducted to evaluate the process feasibility of the first stage of the HITS two-stage coal combustion system. Tests were run in a small (12-in. ID) fluidized bed facility at the Energy Engineering Laboratory, Aerojet Energy Conversion Company, Sacramento, California. The first stage reactor was run with low (0.70%) and high (4.06%) sulfur coals with ash fusion

R. E. Anderson; D. M. Jassowski; R. A. Newton; M. L. Rudnicki

1981-01-01

424

Silicon production in a fluidized bed reactor  

NASA Technical Reports Server (NTRS)

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.

Rohatgi, N. K.

1986-01-01

425

Treating exhaust gas from a pressurized fluidized bed reaction system  

DOEpatents

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.

Isaksson, J.; Koskinen, J.

1995-08-22

426

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

SciTech Connect

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.

Wei-Ping Pan; Yan Cao; John Smith

2008-05-31

427

Staged combustion of rice straw in a fluidized bed  

SciTech Connect

Staged combustion of rice straw has been investigated using an atmospheric bubbling fluidized bed combustor. The combustor has a 300 mm ID and a 3300 mm height. Secondary air was introduced in the freeboard at 1500 mm above the primary air distributor. Rice straw was fed as cylindrical pellets of a 12 mm diameter and 10-15 mm lengths. The obtained results indicate that staged combustion appears an effective technique to reduce NO{sub x} emissions, in particular, at higher operating temperatures. Typically, at 850 C bed temperature, NO{sub x} concentration is reduced by about 50% when 30% of fed air is introduced as secondary air. Staged operation has a slight, non-monotonic effect on SO{sub 2} emission. Combustion efficiency improves with increasing secondary air ratio reaching a maximum value that is mainly attributed to a reduction in fixed carbon loss. With further increase in secondary air ratio, combustion efficiency, however, decreases again since entrained fixed carbon and exhausted carbon monoxide tend to increase. The range of secondary air ratio, over which combustion efficiency improves, expands at higher operating temperatures. (author)

Okasha, F. [Department of Mechanical Engineering, Mansoura University (Egypt)

2007-10-15

428

Fluidized-bed energy technology for biomass conversion  

SciTech Connect

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.

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

1982-01-01

429

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

SciTech Connect

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.

Unknown

2002-03-29

430

Concentration and Velocity Gradients in Fluidized Beds  

NASA Technical Reports Server (NTRS)

In this work we focus on the height dependence of particle concentration, average velocity components, fluctuations in these velocities and, with the flow turned off, the sedimentation velocity. The latter quantities are measured using Particle Imaging Velocimetry (PIV). The PIV technique uses a 1-megapixel camera to capture two time-displaced images of particles in the bed. The depth of field of the imaging system is approximately 0.5 cm. The camera images a region with characteristic length of 2.6 cm for the small particles and 4.7 cm. for the large particles. The local direction of particle flow is determined by calculating the correlation function for sub-regions of 32 x 32 pixels. The velocity vector map is created from this correlation function using the time between images (we use 15 to 30 ms). The software is sensitive variations of 1/64th of a pixel. We produce velocity maps at various heights, each consisting of 3844 velocities. We break this map into three vertical zones for increased height information. The concentration profile is measured using an expanded (1 cm diameter) linearly polarized HeNe Laser incident on the fluidized bed. A COHU camera (gamma=1, AGC off) with a lens and a polarizer images the transmitted linearly polarized light to minimize the effects of multiply scattered light. The intensity profile (640 X 480 pixels) is well described by a Gaussian fit and the height of the Gaussian is used to characterize the concentration. This value is compared to the heights found for known concentrations. The sedimentation velocity is estimated using by imaging a region near the bottom of the bed and using PIV to measure the velocity as a function of time. With a nearly uniform concentration profile, the time can be converted to height information. The stable fluidized beds are made from large pseudo-monodisperse particles (silica spheres with radii (250-300) microns and (425-500) microns) dispersed in a glycerin/water mix. The Peclet number is sufficiently large that Brownian motion of the particles can be ignored and the Reynolds number sufficiently small that particle inertia is negligible. A packed particle bed is used to randomize and disperse the flowing fluid introduced by a peristaltic pump. The bed itself is a rectangular glass cell 8 cm wide (x), 0.8 cm deep and a height of 30.5 cm (z). The depth of field of the camera is approximately 0.5 cm so depth information is averaged. Over flow fluid is returned to the reservoir making a closed loop system. In these experiments the particles form a sediment approximately 5.7 cm high with the pump off and expand to 22 cm with the pump on. For the smaller particles the pump velocity is .5 millimeters per second and 1.1 millimeters per second for the large particles. At this concentration the bed has a very well defined top where particle concentration rapidly drops to zero.

McClymer, James P.

2003-01-01

431

FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION  

SciTech Connect

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.

Jantzen, C

2006-12-22

432

Fluidized Bed Steam Reformer (FBSR) monolith formation  

SciTech Connect

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)

Jantzen, C.M. [Savannah River National Laboratory, Aiken, SC (United States)

2007-07-01

433

Co-firing waste materials in an advanced pressurized fluidized-bed combustor  

SciTech Connect

A study has been undertaken to investigate the technical and economic feasibility of co-firing a pressurized fluidized-bed combustor (PFBC) with coal and municipal or industrial wastes. Focus was placed on the production of electricity and the efficient disposal of wastes for application in a central power station and distributed locations. Wastes considered for co-firing include municipal solid waste (MSW), municipal 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 the performance evaluation completed as part of this study, and provides recommendations for further evaluation.

Rubow, L.N.; DeLallo, M.R.; Zaharchuk, R.

1994-10-01

434

Concept for a super-clean super-efficient pressurized fluidized-bed combustion system  

SciTech Connect

A paper study for a highly efficient, environmentally benign, coal-fired electric power generation system, is presented. This system falls in the category of pressurized fluidized-bed combustion (PFBC) systems which has been dubbed super-clean super-efficient PFBC`s. The system presented starts with the second-generation PFBC concept and adds on advanced gas turbine, a solid oxide fuel cell, a supercritical steam cycle, a second low-temperature rankine cycle which pulls energy from the steam condenser, and inlet air cooling. The thermodynamic efficiency of the system is calculated to be 61.8 percent based on higher heating value (HHV).

Mollott, D.J.; Reed, M.

1994-12-31

435

Scaling of pressurized fluidized beds. Quarterly report, April 1994--July 1994  

SciTech Connect

This 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 fluidized beds.

Glicksman, L.R.; Farrell, P.A.

1994-07-01

436

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

E-print Network

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

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

1980-01-01

437

An investigation of particle mixing in a gas-fluidized bed  

NASA Technical Reports Server (NTRS)

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.

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

1968-01-01

438

Clean coal technology  

NASA Astrophysics Data System (ADS)

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.

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

439

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

SciTech Connect

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

Mutanen, K.I. [A. Ahlstrom Corporation, Varkaus (Finland)

1995-11-01

440

Computational fluid dynamic modeling of fluidized-bed polymerization reactors  

SciTech Connect

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.

Rokkam, Ram [Ames Laboratory

2012-11-02

441

Fluidized bed combustion by?product treatment and leaching of acid soil affects growth and boron acquisition of maize  

Microsoft Academic Search

Fluidized bed combustion bottom ash (FBCBA) from coal burning power plants often contain substances that detrimentally affect plant growth [(e.g., boron (B)] when applied to soil. Leaf symptoms similar to B toxicity appeared when maize (Zea mays L.) was grown during Year?1 of a field experiment where FBCBA was incorporated (6,790 and 13,580 kg ha) in an acidic soil (Aquic

M. Zaifnejad; K. D. Ritchey; R. B. Clark; V. C. Baligar; D. C. Martens

1998-01-01

442

Development of fluidized bed combustion—An overview of trends, performance and cost  

Microsoft Academic Search

The goal of this article is to chart and analyse the development and economical performance of fluidized bed combustion (FBC) and its derivates circulating fluidized bed (CFB) and bubbling fluidized bed (BFB). A descriptive overview is given of the technology and the market penetration is discussed. To make further analysis possible a database is constructed. This database comprises technological and

Joris Koornneef; Martin Junginger

2007-01-01

443

Study of a water-cooled fluidized bed for diesel particle agglomeration  

Microsoft Academic Search

A water-cooled fluidized bed particle trap has been built and tested for diesel particle agglomeration. A theoretical formula incorporating thermophoretic mechanisms into normal fluidized bed filtration has been derived to calculate particle removal efficiency in a water-cooled fluidized bed and validated with published data and measurements from this study. Reasonably good agreement between the measurements and model predictions is achieved.

Ji Ping Shi; Roy M. Harrison

2001-01-01

444

Gas back-mixing studies in membrane assisted bubbling fluidized beds  

Microsoft Academic Search

Fluidized beds employing fine powders are finding increased application in the chemical and petrochemical industry because of their excellent mass and heat transfer characteristics. However, in fluidized bed chemical reactors axial gas back mixing can strongly decrease the conversion and selectivity. By insertion of membranes in fluidized beds large improvements in conversion and selectivity can be achieved, firstly by optimizing

S. A. R. K. Deshmukh; M. van Sint Annaland; J. A. M. Kuipers

2007-01-01

445

Pressurized Fluidized Bed Combustion Second-Generation System Research and Development  

SciTech Connect

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.

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

2002-11-01

446

Meat and bone meal as secondary fuel in fluidized bed combustion  

SciTech Connect

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.

L. Fryda; K. Panopoulos; P. Vourliotis; E. Kakaras; E. Pavlidou [National Technical University of Athens, Athens (Greece). Laboratory of Steam Boilers and Thermal Plants, School of Mechanical Engineering

2007-07-01

447

Internal dust recirculation system for a fluidized bed heat exchanger  

DOEpatents

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.

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

1981-01-01

448

Design review of biomass bubbling fluidized bed boilers  

SciTech Connect

Biomass bubbling fluidized bed boilers, relatively uncommon two decades ago, are now accepted as superior to grate-fired boilers for many applications, particularly where high proportions of pulp and paper mill sludges are to be burned. This paper reviews typical design parameters, advantages and disadvantages over conventional grate-type boilers, the impact of moisture and ash content, the role of fuel and ash chemistry in bed agglomeration and corrosion, air emission and other environmental considerations. A comparison of key design and performance parameters from recent preliminary bids from two Finnish and two north American bubbling fluidized bed boiler manufacturers is presented.

McCann, D. [H.A. Simons Ltd., Vancouver, British Columbia (Canada)

1997-12-31

449

Fluidization onset and expansion of gas-solid fluidized beds  

SciTech Connect

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/).

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

1984-08-01

450

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

SciTech Connect

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.

Wei-Ping Pan; Yan Cao; John Smith

2007-03-31

451

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

SciTech Connect

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

Xianbin Xiao; Hairui Yang; Hai Zhang; Junfu Lu; Guangxi Yue [Tsinghua University, Beijing (China). Department of Thermal Engineering

2005-08-01

452

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

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.

NONE

1995-03-01

453

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

SciTech Connect

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.

Ludlow, James Christopher [U.S. DOE (retired); Panday, Rupen [REM; Shadle, Lawrence J. [U.S. DOE

2013-01-01

454

Combustion Studies of Sawdust in a Bubbling Fluidized Bed  

Microsoft Academic Search

Biomass fuels are difficult to handle due to high moisture and fines content. In the present work, the effect of secondary air injection on combustion efficiency of sawdust in the fluidized bed combustor has been discussed. An enlarged disengagement section is provided to improve combustion of fines. The maximum possible combustion efficiency with saw dust is 99.2 % and is

K. V. N. Srinivasa Rao

2007-01-01

455

Hydrodynamics and erosion modeling of fluidized bed combustors  

Microsoft Academic Search

Hydrodynamics and erosion of Fluidized Bed Combustors (FBCs) containing tubes have been analyzed through the use of the hydrodynamic model, which has been developed at New York University, utilizing a CRAY Y-MP\\/832 supercomputer and a CONVEX C210 minisupercomputer. Particle velocity fields and bed dynamics including bubble formation and motion and bed expansion and collapse were analyzed for high pressure cold

Chunyuan Li; Victor Zakkay

1994-01-01

456

Agglomeration in bio-fuel fired fluidized bed combustors  

Microsoft Academic Search

This paper presents results from systematic agglomeration experiments in a straw-fired laboratory-scale fluidized bed combustor and a theoretical study of the phenomena. Experiments were carried out at different operating conditions. Defluidization resulting from agglomeration occurred in all experiments. The agglomeration tendency is represented by the time before defluidization is detected. The results show that the temperature has a pronounced effect

Weigang Lin; Kim Dam-Johansen; Flemming Frandsen

2003-01-01

457

Flue gas desulfurization in an internally circulating fluidized bed reactor  

Microsoft Academic Search

An internally circulating fluidized bed reactor (ICFBR) was used as a desulfurization apparatus in this study. The height of the bed was 2.5 m, and the inner diameter was 9 cm. The bed materials were calcium sorbent and silica sand. The effects of the operating parameters of the flue gas desulfurization including relative humidity, particle size of the calcium sorbent,

Chen Yeon Chu; Shyh Jye Hwang

2005-01-01

458

Attrition of sorbents during fluidized bed calcination and sulphation  

Microsoft Academic Search

The attrition behavior of two different limestones during calcination and sulphation in fluidized beds has been investigated by a combination of experimental techniques. The aim of the study is to shed light on the interactions between sorbent attrition and the change of particle mechanical and morphological properties associated with the progress of chemical reactions. A number of different experimental techniques

Fabrizio Scala; Piero Salatino; Renee Boerefijn; Mojtaba Ghadiri

2000-01-01

459

Heat exchanger support apparatus in a fluidized bed  

DOEpatents

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.

Lawton, Carl W. (West Hartford, CT)

1982-01-01

460

KINETICS OF CARBON DEPOSITION IN A FLUIDIZED BED  

Microsoft Academic Search

Rate data were obtained for the deposition of carbon films from methane ; and acetylene in fluidized beds of alumina, uranium dioxide, uranium monocarbide, ; uranium dicarbide, and a solid solution of uranium-thorium dicarbide powders. ; These carbon films were shown to provide excellent protection for the powdered ; fertile material against attack by hot concentrated nitric-acid solutions. The ;

Joseph H. Oxley; Arthur C. Secrest; Neil D. Veigel; John M. Blocher

1961-01-01

461

Lagrangian Approach to Study Catalytic Fluidized Bed Reactors  

NASA Astrophysics Data System (ADS)

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

Madi, Hossein

2013-03-01

462

Selecting fluidized-bed boilers: three case studies  

Microsoft Academic Search

Three projects representing three different types of owners with different reasons for considering new steam production facilities all ended up selecting the circulating fluidized-bed boiler (CFBC) despite their different evaluating criteria. The authors review key considerations used for an expanding public university physical plant, a small power producer desiring to use biomass fuel in a new generating facility, and a

M. W. McComas; G. L. Gould; L. J. Thies

1987-01-01

463

In silico modeling of in situ fluidized bed melt granulation.  

PubMed

Fluidized bed melt granulation has recently been recognized as a promising technique with numerous advantages over conventional granulation techniques. The aim of this study was to evaluate the possibility of using response surface methodology and artificial neural networks for optimizing in situ fluidized bed melt granulation and to compare them with regard to modeling ability and predictability. The experiments were organized in line with the Box-Behnken design. The influence of binder content, binder particle size, and granulation time on granule properties was evaluated. In addition to the response surface analysis, a multilayer perceptron neural network was applied for data modeling. It was found that in situ fluidized bed melt granulation can be used for production of spherical granules with good flowability. Binder particle size had the most pronounced influence on granule size and shape, suggesting the importance of this parameter in achieving desired granule properties. It was found that binder content can be a critical factor for the width of granule size distribution and yield when immersion and layering is the dominant agglomeration mechanism. The results obtained indicate that both in silico techniques can be useful tools in defining the design space and optimization of in situ fluidized bed melt granulation. PMID:24607215

Aleksi?, Ivana; Duriš, Jelena; Ili?, Ilija; Ibri?, Svetlana; Paroj?i?, Jelena; Sr?i?, Stanko

2014-05-15

464

Dehydrogenations in fluidized bed: Catalysis and reactor engineering  

Microsoft Academic Search

Dehydrogenation is a widely exploited route for large scale production of pure olefins. Its industrial application is however complicated by clashing kinetic and thermodynamic constraints. A commercial bubbling fluidized bed technology for isobutylene production from isobutane has been developed to solve these constraints. An economically attractive implementation was achieved by defining an optimal synergy between chromia alumina catalyst design and

Domenico Sanfilippo

465

Fuzzy Modeling for an Anaerobic Tapered Fluidized Bed Reactor  

Microsoft Academic Search

Fuzzy modeling has great adaptability to the variations of system configuration and operation conditions. This paper investigates the fuzzy modeling of a laboratory scale system of anaerobic tapered fluidized bed reactor (ATFBR). The studied system is the anaerobic digestion of synthetic wastewater derived from the starch processing industries. The experiment was carried out in a mesophilic ATFBR reactor with mesoporous

Zsolt Csaba Johanyák; Rangasamy Parthiban; Ganesan Sekaran

466

Computational Fluid Dynamics Simulation of Fluidized Bed Polymerization Reactors  

Microsoft Academic Search

Fluidized beds (FB) reactors are widely used in the polymerization industry due to their superior heat- and mass-transfer characteristics. Nevertheless, problems associated with local overheating of polymer particles and excessive agglomeration leading to FB reactors defluidization still persist and limit the range of operating temperatures that can be safely achieved in plant-scale reactors. Many people have been worked on the

Rong Fan

2006-01-01

467

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

SciTech Connect

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.

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

1996-02-01

468

Test results from the Department of Energy`s Pressurized Fluidized Bed Combustion Hot Gas Cleanup Program  

SciTech Connect

Presented here is a summary of operations and conclusions from the last two test campaigns of the Department of Energy`s Pressurized Fluidized Bed Combustion Hot Gas Cleanup Program which was implemented by the American Electric Power Service Corporation. In these tests, the Westinghouse Advanced Particle Filter (APF) operated on a one-seventh flow from the Tidd 70-MWe Pressurized Fluidized Bed Combustor. During these tests, the filter operated as predicted with extremely high particulate removal. During the combined test periods, more than 2,800 hours of operation were accumulated -- two operational periods lasted more than 650 hours. The completion of this program brings the total coal fired operating time of the APF to 5,854 hours.

Dennis, R.A.

1995-12-01