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1

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

2

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

3

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

4

HEAT GENERATION OF SPENT BED MATERIALS FROM ATMOSPHERIC FLUIDIZED-BED COMBUSTION OF COAL  

EPA Science Inventory

The report describes an experimental investigation of the hydration process of spent bed material (with a calcium/sulfur ratio of 3) from an atmospheric fluidized bed combustor for maximum temperature, rate of temperature rise, and controllability of temperature rise with various...

5

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

6

Use of oil shale for SOâ emission control in atmospheric-pressure fluidized-bed coal combustors  

Microsoft Academic Search

Oil shale--SOâ reactivity, determined with a thermogravimetric analyzer, was used to estimate the quantity of oil shale required to reduce SOâ concentration in the effluent gas sufficiently to meet the SOâ emission standard in atmospheric-pressure fluidized-bed coal combustion (AFBC). It was calculated that the oil shale could reduce the SOâ concentration in the effluent gas from FBC units below the

W. I. Wilson; R. B. Snyder; I. Johnson

1979-01-01

7

Pulsed atmospheric fluidized bed combustor apparatus  

DOEpatents

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

Mansour, Momtaz N. (Columbia, MD)

1993-10-26

8

A field study on the trace metal behavior in atmospheric circulating fluidized-bed coal combustion  

SciTech Connect

Trace element behavior in atmospheric circulating fluidized-bed combustion (CFBC) of Venezuelan bituminous coal was studied by determining particle size distributions in the CFBC flue gas. The size distributions of calcium, iron, aluminium, and 21 trace elements, Sc, V, Cr, Mn, Co, Ni, Zn, Ga, As, Se, Sr, Cd, Sb, Cs, Ba, La, Ce, Sm, Lu, Pb, and Th, in the size range 0.01--70{micro}m, were determined by collecting aerosols with a low-pressure impactor-cyclone sampling train from the flue gases of an 80-MW(th) CFBC boiler upstream of the electrostatic precipitator. The collected samples were analyzed gravimetrically and with instrumental neutron activation analysis (INAA), particle-induced X-ray emission analysis (PIXE), and inductively coupled plasma mass spectrometry (ICP-MS). The number size distributions of the aerosols were determined with a differential electrical mobility method in the size range 0.01--0.8 {micro}m. In the ultrafine particle mode, i.e., D{sub p} < 0.1 {micro}m, the CFBC number concentrations varied strongly during the experiments, being one to two orders of magnitude lower than those observed in pulverized coal combustion. For all of the elements studied, 75% or more were found in particles larger than 5{micro}m. None of the studied elements showed significant vaporization and subsequent chemical surface reaction or condensation in the CFBC. The Sr, Se, V, Zn, Ga, Cs, Ba, La, Sm, Lu, and Th size distributions resembled those of aluminium, suggesting their occurrence in aluminosilicate-rich particles in the fly ash. The association of the trace elements with aluminium in the fly ash particles may result from reactions of the trace elements with the aluminosilicate mineral particles inside the burning coal particles, or their initial occurrence in association with these minerals.

Lind, T.; Kauppinen, E.I.; Jokiniemi, J.K.; Maenhaut, W.

1994-12-31

9

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... combustion, has encouraged many steam producers/ users to investigate switching from oil or gas to coal. Changes in federal regulations encouraging cogeneration have further enhanced the economic incentives for primary fuel switching. However...

Thunem, C.; Smith, N.

10

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

11

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

12

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

13

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

14

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

15

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

16

Pulsed atmospheric fluidized bed combustor apparatus and process  

DOEpatents

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

Mansour, Momtaz N. (Columbia, MD)

1992-01-01

17

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

18

Atmospheric fluidized bed combustor development program. Final report  

SciTech Connect

The objective of this project was to demonstrate and promote the commercialization of a coal-fired atmospheric fluidized bed combustion (AFBC) system, 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 in the 1 x 10{sup 6} to 10 x 10{sup 6} Btu/hr capacity range. 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. The project itself was separated into three levels: (1) feasibility, (2--3) subsystem development and integration, and (4) proof-of-concept. In Level (1), the technical and economic feasibility of a 1 million Btu/hr coal-fired AFBC air heater was evaluated. In Level (2--3), the complete EER fluidized bed combustor (1.5 million Btu/hr) system was developed and tested. The goal or reducing SO{sub 2} emissions to 1.2 lb/10{sup 6} Btu, from high sulfur Ohio coal, was achieved by adding limestone with a Ca/S (coal) ratio of {approximately} 3.0. Finally, in Level (4), the proof-of-concept system, a 2.2 million Btu/hr unit was installed and successfully operated at Cedar Lane Farms, a commercial nursery in Ohio.

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

1995-12-01

19

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...

20

Coal-feeding mechanism for a fluidized bed combustion chamber  

DOEpatents

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

Gall, Robert L. (Morgantown, WV)

1981-01-01

21

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

SciTech Connect

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

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

1980-01-01

22

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

23

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

24

Pneumatic and Hydraulic Systems in Coal Fluidized Bed Combustor  

Microsoft Academic Search

Problem statement: This study designed the pneumatic and hydraulic systems in coal fluidized bed combustor. These are fluidization of silica sand bed material, Air distributor, centrifugal fan, electric motor power drive and surface heat exchanger. Approach: The effects of increased gas velocity on silica sand and the resultant drag force formed the basic equations in fluidization. Air distributor was introduced

I. A. Adetunde

25

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

26

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

27

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

28

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

29

Planning, construction and operation of the 35 MW sub th-test facility Flingern for firing bituminous coal in an atmospheric fluidized bed furnace  

NASA Astrophysics Data System (ADS)

Clean combustion of high ash and high sulfur coal with the boiler, retrofitted from traveling grate stoker to FBC was demonstrated. Within 4,200 operating hours 14,500 t of bituminous coal ranking from high grade to low grade were fired, generating 105,000 t of steam at 17 bar and 400 C. During the 18 month test operation important knowledge concerning process and systems to burn coal in the fluidized bed were gained. The technical feasibility in industrial scale was demonstrated.

Krischke, H. G.; Chalupnik, R. W.; Masuch, H. P.

1982-11-01

30

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 ...

31

Self-heat recuperative fluidized bed drying of brown coal  

Microsoft Academic Search

Brown coal drying based on self-heat recuperation (SHR) technology which recovers effectively both latent and sensible heat was developed to reduce energy consumption which is required during drying. A fluidized bed dryer (SHR–FBD) with heat exchanger immersed inside the bed was adopted as the evaporator. To evaluate the energy efficiency of the proposed SHR–FBD system, a comparison to the available

Muhammad Aziz; Yasuki Kansha; Atsushi Tsutsumi

2011-01-01

32

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 investigated the use of a fluidized bed atmospheric pressure plasma (APP) as a possible pasteurization method of inoculum. Almonds were placed in a fluidized bed APP treatment chamber fixed to an Enercon Dyne

Heller, Barbara

33

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

34

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

35

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

36

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

37

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 ...

38

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...

39

Scale-up circulating fluidized bed coal combustors. Final report  

SciTech Connect

Circulating fluidization is a promising technology for designing efficient coal combustors with high solid feed rates. Unfortunately, limited understanding of circulating fluidized beds (CFB) has rendered design extrapolations from pilot reactors to full-scale plants both empirical and expensive. In CFBs, hydrodynamics and heat transfer are difficult to predict, and the behavior of the flow under scale-up is unclear. Thus the objectives of this research were to quantify the effect of scale-up on the hydrodynamics of CFB combustors, to carry out a rigorous analysis of the flow and heat transfer in vertical gas-solid risers, and to interact with industry at all stages of this work. The importance of this research resides in the great number of CFB coal-burning powerplants that may benefit from its results. At the completion of this work, the results have exceeded the expectations outlined in the original proposal. The present report summarizes these accomplishments, which have led to five archival publications, two reviewed conference papers, twelve presentations, various quarterly reports, and the award of five graduate degrees.

Louge, M.Y.

1991-11-20

40

Scale-up circulating fluidized bed coal combustors  

SciTech Connect

Circulating fluidization is a promising technology for designing efficient coal combustors with high solid feed rates. Unfortunately, limited understanding of circulating fluidized beds (CFB) has rendered design extrapolations from pilot reactors to full-scale plants both empirical and expensive. In CFBs, hydrodynamics and heat transfer are difficult to predict, and the behavior of the flow under scale-up is unclear. Thus the objectives of this research were to quantify the effect of scale-up on the hydrodynamics of CFB combustors, to carry out a rigorous analysis of the flow and heat transfer in vertical gas-solid risers, and to interact with industry at all stages of this work. The importance of this research resides in the great number of CFB coal-burning powerplants that may benefit from its results. At the completion of this work, the results have exceeded the expectations outlined in the original proposal. The present report summarizes these accomplishments, which have led to five archival publications, two reviewed conference papers, twelve presentations, various quarterly reports, and the award of five graduate degrees.

Louge, M.Y.

1991-11-20

41

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

42

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

43

Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment: 1000-H Laboratory Test A.  

National Technical Information Service (NTIS)

A laboratory test program is described to evaluate the corrosion behavior of several metallic alloys, coatings, claddings, and weldments in support of the atmospheric fluidized-bed air heater experiment. Results are presented from the first 1000-h test (T...

K. Natesan, W. Podolski

1987-01-01

44

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

45

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

E-print Network

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

Spiteri, Raymond J.

46

Scaling factors for fluidized-bed coal combustion. Phase 1  

SciTech Connect

The objective of the Phase I project was to develop preliminary rules for scaling-up experimental fluidized-bed combustors to commercial size. Scaling parameters were developed from the equations of motion for the fluid and particles when scales for the dependent variables were introduced. The scales used in non-dimensionalization were selected specifically for the problem of fluidized beds. Results show that the ratio of the drag forces to the gravitational forces on an individual particle determines whether the bed is packed or fluidized. The parameter also correlates the transition to the turbulent state. Scaling parameters predictions of flow regime transition were compared to data assembled from the literature. Implications for the construction of scale-up of small-scale experiments are also discussed.

Gillis, J.C.

1984-07-01

47

A model of coal particle drying in fluidized bed combustion reactor  

SciTech Connect

Experimental and theoretical investigation on drying of a single coal particle in fluidized bed combustor is presented. Coal particle drying was considered via the moist shrinking core mechanism. The results of the drying test runs of low-rank Serbian coals were used for experimental verification of the model. The temperature of the coal particle center was measured, assuming that drying was completed when the temperature equalled 100{sup o}C. The influence of different parameters (thermal conductivity and specific heat capacity of coal, fluidized bed temperature, moisture content and superheating of steam) on drying time and temperature profile within the coal particle was analyzed by a parametric analysis. The experimentally obtained results confirmed that the moist shrinking core mechanism can be applied for the mathematical description of a coal particle drying, while dependence between drying time and coal particle radius, a square law relationship, implicates heat transfer control of the process and confirms the validity of assumptions used in modeling.

Komatina, M.; Manovic, V.; Saljnikov, A. [Natural Resources Canada, Ottawa, ON (Canada). CANMET, Energy Technology Centre

2007-02-15

48

Preliminary report on corrosion analysis of heat exchanger tubes from a fluidized-bed coal combustor. [2 references  

Microsoft Academic Search

The Energy Division of ORNL is planning the construction of a fluidized-bed coal combustor pilot plant. In order to gain preliminary materials compatibility information, a small scale MIUS fluidized bed was constructed, and a testing program of candidate heat exchanger tube materials was initiated. Candidate materials included Incoloy 800, Inconel 600, type 304 and 316 stainless steel, and aluminized Incoloy

R. H. Cooper; J. H. DeVan

1977-01-01

49

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

50

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

EPA Science Inventory

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

51

PROCESS WASTEWATER TREATABILITY STUDY FOR WESTINGHOUSE FLUIDIZED-BED COAL GASIFICATION  

EPA Science Inventory

The paper discusses a joint program (The U.S. Department of Energy, the Gas Research Institute, and the U.S. Environmental Protection Agency) to develop performance data, design parameters, conceptual designs, and cost estimates for treating wastewaters from a fluidized-bed coal ...

52

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...

53

Effect of coal particle size distribution on agglomerate formation in a fluidized bed combustor (FBC)  

Microsoft Academic Search

An investigation was conducted to find out the reasons for agglomeration in a fluidized bed combustion (FBC) power plant. Two typical coal samples were collected for investigation. The first sample was collected when the plant was operating smoothly, and the second was collected immediately after agglomeration. These two samples were subjected to analysis. It was observed that agglomeration of the

G. Venkat Reddy; S. K. Mahapatra

1999-01-01

54

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

EPA Science Inventory

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

55

CFD modeling of oxy-coal combustion in circulating fluidized bed  

Microsoft Academic Search

Based on the Computational Fluid Dynamics (CFD) method, the previously established and validated 2-dimensional model was employed to predict the oxy-coal combustion processes in a 50kW circulating fluidized bed (CFB) at Southeast University, China. The simulated processes of coal conversion in our CFB combustion system included particle drying, dry coal devolatilization, volatile combustion, char combustion, char gasification and SO2 emission.

Wu Zhou; Changsui Zhao; Lunbo Duan; Daoyin Liu; Xiaoping Chen

56

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

57

Natural-sorbent attrition and elutriation characteristics in fluidized-bed coal combustors  

SciTech Connect

Laboratory test methods have been developed to measure the attrition and elutriation characteristics of limestones in an atmospheric-pressure fluidized-bed coal combustor (AFBC) at 850/sup 0/C. The attrition constant and elutriation rate were determined for a group of limestones when the system is assumed to be at steady state; that is, after sorbent breakup due to thermal shock and decrepitation during calcination of the sorbent feed are completed. An attrition model has been developed to analyze the laboratory data to predict sorbent performance in AFBCs. The attrition model assumes that the particle disintegration occurs from the abrasive removal of material from the surface of the particle rather than by particle fracture. The attrition constants of the limestones tested ranged from 1.5 x 10/sup -6/ sec/sup -1/ to 9.2 x 10/sup -8/ sec/sup -1/, and the elutriation rate had a fractional mass loss which ranged from 8.1 x 10/sup -8/ min/sup -1/ to 1.0 x 10/sup -3/ min/sup -1/. The test methods and techniques utilized by the model are undergoing refinement to improve the accuracy of the prediction. The attrition and elutriation of a sorbent in a fluidized-bed combustor affects the sorbent performance in a complex manner. The obvious case is the extreme situation where so much sorbent material is lost from the bed via attrition and elutriation that a constant bed height cannot be maintained. Because this aspect is an important consideration in sorbent selection, standard laboratory test methods have been developed to measure the attrition and elutriation characteristics of limestones in AFBCs.

Wilson, W.I.; Fee, D.C.; Myles, K.M.; Johnson, I.; Fan, L.S.

1981-01-01

58

Heat and mass transfer in fixed and fluidized beds  

Microsoft Academic Search

This paper presents papers dealing with the fluidized-bed combustion of coal. Topics considered include coal-fluidized bed boilers, heat transfer in fluidized beds, catalytic reactions, combustion kinetics, process heat reactors, gas-solid fluidized beds, fluidized-bed combustion technology, the combustion of milled peat, coal-water slurries, coal gasification, sulfur dioxide absorption, air pollution control, fluidized bed combustors, fluidized-bed drying, propane combustion, mathematical models, hydrodynamics,

W. P. M. vanSwaaij; N. H. Afgan

1986-01-01

59

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

SciTech Connect

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

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

1991-02-01

60

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

61

Method for stabilizing particulate low rank coal in a fluidized bed  

SciTech Connect

An improved method is described for drying particulate low rank coal in a fluidized bed. The improvement comprises fluidizing the coal above a first portion of a gas flow distributor using a hot fluidizing gas and fluidizing the coal above a second portion of the gas flow distributor with a recycle gas stream at a temperature less than about 200/sup 0/ F. The second portion of the gas flow distributor is located near the coal discharge from the coal drying zone to cool overheated coal particles.

Ottoson, J.D.

1985-01-29

62

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

63

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

Microsoft Academic Search

A numerical algorithm is developed for a detailed 3D simulation of the gas\\/particle flow behavior used for drying of sludge under flue gas atmosphere in the riser section of a circulating fluidized bed. The gas phase is described with standard kappa - ? turbulence model, whereas a Lagrangian formulation with a stochastic particle dispersion model is adopted for the particulate

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

2010-01-01

64

Technology Assessment for an Atmospheric Fluidized-Bed Combustion Demonstration Plant.  

National Technical Information Service (NTIS)

The status of atmospheric fluidized-bed combustion (AFBC) technology was examined and, in particular, the data base available for successful design, construction, and operation of an AFBC demonstration plant of 150 to 250 MW(e) capacity. The basic conclus...

M. Siman-Tov, N. C. Bradley, S. G. DeCicco, E. C. Fox, T. G. Godfrey

1979-01-01

65

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

66

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...

67

Understanding the behavior of Australian black coals in pressurized fluidized bed combustion  

SciTech Connect

Ultimately, this study aims to predict the coal combustion efficiency in an industrial pressurized fluidized bed combustor (PFBC) for Australian black coals. This combustion efficiency depends predominantly upon the rate of elutriation of fine carbon particles, which is proportional to bed carbon loading in atmospheric experiments. The bed carbon loading is, in turn, dependent upon the rate of combustion of char particles within the PFBC. A novel batch-fed reactor has been designed, constructed and commissioned to enable separation and study of the mechanisms of coal devolatilization, char combustion and fine carbon particle elutriation in a PFBC and extraction of coal-specific parameters to describe these processes. The attrition and char combustion rates can only be determined experimentally and it is essential to match the environment around each coal particle, so that the results may be translated to the industrial scale. Therefore, the rig was designed for identical conditions of pressure, temperature, particle size and fluidizing velocity within the bed to those used industrially. The exhaust gas is analyzed continuously for oxygen, carbon dioxide, carbon monoxide and hydrocarbons as a function of time after coal injection, allowing separation and identification of the devolatilization and char combustion stages as well as measurement of the combustion rates. The elutriated carbon particles undergo minimal freeboard combustion and are collected in a cyclone and an in-line filter over any period of time during the experiment, for subsequent analysis. The sand bed containing the rig for collection and characterization of the partially burnt char particles. The rig is mostly computer-controlled and the design was subjected to a hazards analysis before construction. Results from the rig will be used in a mathematical model to predict the performance of the coals in industrial-scale PFBC.

Stubington, J.F.; Wang, A.L.T.; Cui, Y.

1999-07-01

68

Two-dimensional computational fluid dynamics simulation of coal combustion in a circulating fluidized bed combustor  

Microsoft Academic Search

A computational fluid dynamics (CFD) approach was applied to simulate the air-coal two-phase flow and combustion characteristics in a 50kW circulating fluidized bed (CFB) combustor. Eulerian–Granular multiphase model with a drag coefficient correction based on the extended energy-minimization multi-scale (EMMS\\/matrix) model was used to study the gas–solid hydrodynamics. One energy conservation equation was applied to the mixture of gases and

W. Zhou; C. S. Zhao; L. B. Duan; C. R. Qu; X. P. Chen

2011-01-01

69

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

70

Temperatures of coal particle during devolatilization in fluidized bed combustion reactor  

SciTech Connect

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

Komatina, M.; Manovic, V.; Saljnikov, A. [University of Belgrade, Belgrade (Serbia). Faculty of Mechanical Engineering

2006-11-15

71

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

SciTech Connect

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

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

1999-07-01

72

A Novel Atmospheric Freeze-Drying System Using a Vibro-Fluidized Bed with Adsorbent  

Microsoft Academic Search

Atmospheric freeze drying (AFD) in a vibro-fluidized bed dryer coupled with an adsorbent and multimode heat input is proposed for dehydration of food products at lower cost than the traditional freeze-drying process under vacuum. The aim of this project is to study the proposed AFD system using a vortex tube to produce low-temperature dry air, an alternative for producing dried

S. M. A. Rahman; A. S. Mujumdar

2008-01-01

73

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

Microsoft Academic Search

\\u000a A numerical algorithm is developed for a detailed 3D simulation of the gas\\/particle flow behavior used for drying of sludge\\u000a under flue gas atmosphere in the riser section of a circulating fluidized bed. The gas phase is described with standard ?\\u000a ? ? turbulence model, whereas a Lagrangian formulation with a stochastic particle dispersion model is adopted for the particulate

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

74

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

75

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

76

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

NASA Astrophysics Data System (ADS)

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

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

77

Materials performance in the atmospheric fluidized-bed cogeneration air heater experiment  

SciTech Connect

The Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment (ACAHE) sponsored by the US Department of Energy (DOE) was initiated to assess the performance of various heat-exchanger materials to be used in fluidized-bed combustion air heater systems. Westinghouse Electric Corporation, through subcontracts with Babcock Wilcox, Foster Wheeler, and ABB Combustion Engineering Systems, prepared specifications and hardware for the ACAHE tests. Argonne National Laboratory contracted with Rockwell International to conduct tests in the DOE atmospheric fluidized-bed combustion facility. This report presents an overview of the project, a description of the facility and the test hardware, the test operating conditions, a summary of the operation, and the results of analyzing specimens from several uncooled and cooled probes exposed in the facility. Extensive microstructural analyses of the base alloys, claddings, coatings, and weldments were performed on specimens exposed in several probes for different lengths of time. Alloy penetration data were determined for several of the materials as a function of specimen orientation and the exposure location in the combustor. Finally, the data were compared with earlier laboratory test data, and the long-term performance of candidate materials for air-heater applications was assessed.

Natesan, K.; Podolski, W.; Wang, D.Y.; Teats, F.G. (Argonne National Lab., IL (United States)); Gerritsen, W.; Stewart, A.; Robinson, K. (Rockwell International Corp., Canoga Park, CA (United States))

1991-02-01

78

Materials performance in the atmospheric fluidized-bed cogeneration air heater experiment  

SciTech Connect

The Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment (ACAHE) sponsored by the US Department of Energy (DOE) was initiated to assess the performance of various heat-exchanger materials to be used in fluidized-bed combustion air heater systems. Westinghouse Electric Corporation, through subcontracts with Babcock & Wilcox, Foster Wheeler, and ABB Combustion Engineering Systems, prepared specifications and hardware for the ACAHE tests. Argonne National Laboratory contracted with Rockwell International to conduct tests in the DOE atmospheric fluidized-bed combustion facility. This report presents an overview of the project, a description of the facility and the test hardware, the test operating conditions, a summary of the operation, and the results of analyzing specimens from several uncooled and cooled probes exposed in the facility. Extensive microstructural analyses of the base alloys, claddings, coatings, and weldments were performed on specimens exposed in several probes for different lengths of time. Alloy penetration data were determined for several of the materials as a function of specimen orientation and the exposure location in the combustor. Finally, the data were compared with earlier laboratory test data, and the long-term performance of candidate materials for air-heater applications was assessed.

Natesan, K.; Podolski, W.; Wang, D.Y.; Teats, F.G. [Argonne National Lab., IL (United States); Gerritsen, W.; Stewart, A.; Robinson, K. [Rockwell International Corp., Canoga Park, CA (United States)

1991-02-01

79

Cofiring of coal and biomass in advanced fluidized bed gasifiers  

SciTech Connect

The cofiring of coal and biomass is now being considered by the scientific community and as a viable option to the sustained year round operation of biomass based plants which are currently limited in duration due to the biomass growing season dependency. There are many industrial applications which would also accommodate the use of waste residuals including biomass resources for production of cogenerated electricity, steam and syn-gas based chemicals and fuels (methanol, ethanol, ammonia, etc.). A good example of this is the bagasse-based biomass project NREL is currently supporting using the IGT U-Gas gasifier technology which is under way in a pilot plant operation located in Maui, Hawaii in the sugar cane fields accessible to a nearby seaport which could accommodate other alternate fuel handling facilities. In addition the use of bagasse types of biomass wastes can support the environmental clean-up and disposal of these and other types of wastes such as wood wastes from pulp and paper mills, and vegetation and floral wastes in tropical regions such as South Asia. Using cofiring of coal fines and biomass can be economically attractive in areas where high and low grade coal is mined and can add to the electrification and district heating of these remotely located villages and hamlets. Large scale facilities can be envisioned, but there is a need for testing and proving these options in areas where there is no existing infrastructure for providing local electric and district heat. Industrial scale coal-based IGCC facilities are economically operated in many places in China and in urban industrial complexes such as the Shanghai Coke and Chemical Plant Group (SCCPG) in the southern region of Shanghai (SCCPG has a license for the U-Gas gasification technology in China).

Hoppe, J.A. [CSI Engineering, PC Montgomery Village, MD (United States)

1998-12-31

80

Standardized test methods for investigating attrition and elutriation characteristics of natural sorbents in fluidized-bed coal combustors  

SciTech Connect

Experimental techniques and standard laboratory test methods have been developed to measure the attrition and elutriation characteristics of limestones in an atmospheric-pressure fluidized-bed coal combustor (AFBC) at 850/sup 0/C. The laboratory test device used to measure the attrition characteristics of a sorbent is a small laboratory size fluidized bed. The elutriation rate and the attrition constant were determined for a group of limestones when the system is assumed to be at steady state; i.e., after sorbent breakup due to thermal shock and decrepitation during calcination of the sorbent feed has occurred. An attrition model has been developed to analyze the laboratory data and to predict sorbent performance in AFBCs. The attrition model, based on a stoichastic model proposed by Fan and Srivastava, assumes that the particle disintegration is such that the abrasive removal of material occurs only from the surface of the particle. The attrition constants of the limestones tested ranged from 1.5 x 10/sup -6/ sec/sup -1/ to 9.2 x 10/sup -8/ sec/sup -1/, and the elutriation rate had a fractional mass loss which ranged from 8.1 x 10/sup -8/ min/sup -1/ to 1.0 x 10/sup -3/ min/sup -1/. The standard tests utilized by the model are undergoing refinement to improve the accuracy of the predictions.

Wilson, W.I.; Fee, D.C.; Myles, K.M.

1981-01-01

81

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

SciTech Connect

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

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

1980-10-01

82

Regeneration of sulfated dolomite from a coal-fired FBC process by reductive decomposition of calcium sulfate in a fluidized bed. [9 refs  

Microsoft Academic Search

Dolomite or limestone is sulfated when used as a sulfur-sorbent in the fluidized bed combustion of high sulfur coal. Dolomite that was sulfated by this process was regenerated for subsequent reuse as a sorbent to CaO . MgO by reductive decomposition in a fluidized bed. Regeneration was accomplished by the incomplete combustion of methane in a fluidized bed of sulfated

John C. Montagna; John F. Lenc; Gerhard J. Vogel; Albert A. Jonke

1977-01-01

83

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

84

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

NASA Technical Reports Server (NTRS)

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

Fields, S. F.

1977-01-01

85

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

SciTech Connect

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

Reed, M.R.; Dicker, J.M.; Gagliardi, C.R.; Sommerhalter, K.L.; Tsao, T.R.; Wang, S.I. (Air Products and Chemicals, Inc., Environmental and Energy Div., Allentown, PA (US))

1992-01-01

86

Trace metal capture by various sorbents during fluidized bed coal combustion  

SciTech Connect

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

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

1996-06-01

87

Attrition and elutriation phenomena in industrial atmospheric fluidized bed combustors  

SciTech Connect

Attrition and elutriation in large-scale AFBC systems depend on the design of the feed system, bed hydrodynamics and freeboard cooling. At present, no generalized correlation exists to predict these effects. It is suggested that routine solid samples for size analysis be taken before the solids enter the bed. In this way, correlations can be developed to predict the attrition in the feed system and in the bed separately. Secondly, data on the solids loading in the freeboard should be taken and related to bubble size, bubble velocity, bubble frequency and bed expansion. Such information can be obtained in a cold bed for lack of measuring techniques in hot beds. Accurate rate expressions for attrition and elutriation specific to coal ash, limestone, and char can then be developed to predict the performance of AFBC systems.

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

1980-01-01

88

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

89

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

90

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

SciTech Connect

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

Preuit, L C; Wilson, K B

1980-05-01

91

Supplemental Comprehensive Report to Congress - Clean Coal Technology Program. Tidd Pressurized Fluidized Bed Combustion (PFBC) Project  

SciTech Connect

The Department of Energy (DOE) in February 1987 submitted a Comprehensive Report to Congress for a Clean Coal Technology (CCT) project entitled {open_quotes}Tidd PFBC (Pressurized Fluidized Bed Combustion) Demonstration Project.{close_quotes} In that document, DOE reported to Congress that the Government share of project costs would be $60,200,000 and that the participant agreed to absorb any cost overruns, even though the public law contained provisions which would allow DOE to share in project cost growths up to 25 percent of the original financial assistance. This Supplemental Report is being submitted because DOE now intends to increase its contribution to the project by approximately 11 percent to facilitate extension of the original 3-year operating period by one additional year. DOE`s overall percentage cost share resulting from this extension will not exceed DOE`s overall percentage cost share in the original agreement.

Not Available

1994-03-01

92

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

93

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...

94

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

95

Measurement of circulation rates of coal particles in standpipe of a circulating fluidized bed system (CFBS) using radiotracer technique  

Microsoft Academic Search

Radiotracer technique was applied to measure the circulation rates of fine coal particles in standpipe of a pilot-scale bubbling\\u000a circulating fluidized bed system (CFBS). 198Au adsorbed on coal particles was used as a radiotracer. The radiotracer was injected into the standpipe and monitored at\\u000a four different downstream locations. The circulation times and circulation rates were determined from the measured tracer

H. J. Pant; V. K. Sharma; M. Vidya Kamudu; S. G. Prakash; S. Krishna Moorthy; G. Anandam; N. V. S. Ramani; Gursharan Singh

2009-01-01

96

The advantages of fluidized bed carburizing  

Microsoft Academic Search

Currently, in the thermochemical treatment practice, different carburizing techniques are used. Among these, the fluidized bed carburizing is a special technique that provides high heat and mass transfer. Also, the fluidized bed accelerates the chemical reaction rates and modifies the carbon adsorption and diffusion in the atmosphere–steel interface. Taking account of both these and of that, the fluidized bed has

Daniela Dragomir; Leontin Druga

2001-01-01

97

Atmospheric fluidized-bed combustor design whose performance will significantly exceed conventional FBC operation performance. Final report  

Microsoft Academic Search

It is the goal of this project to bring forth a bench-scale design and test program to establish the merits of the circulating bed concept of atmospheric fluidized bed combustors (AFBC) and to show what the process development unit elements might be. The circulating fluid dynamics were modeled. From such a model the physical dimensions of a test system and

K. H. Hsiao; Y. Y. Lin; G. W. Guglietta; W. R. Cares; L. D. Fraley; W. C. Schreiner; M. Schlossman; A. Solbakken

1982-01-01

98

An experimental study of temperature of burning coal particle in fluidized bed  

SciTech Connect

The purpose of this study was to investigate the temperature of coal particle during combustion in fluidized bed (FB). It is necessary to know the coal particle temperature in order to predict kinetics of chemical reactions within and at the surface of coal particle, accurate NOx and SO{sub 2} emission, fragmentation, attrition, the possibility of ash melting, etc. The experimental investigations were conducted in order to obtain the reliable data on the temperature of particle burning in the FB. A method using thermocouple was developed and applied for measurements. Thermocouple was inserted in the center of the particle shaped into spherical form with various diameters: 5, 7, 8, and 10 mm. Two characteristic types of low-rank Serbian coals were investigated. Experiments were done at the FB temperature in the range of 590-710{sup o}C. Two types of experiments were performed: (I) combustion using air as fluidization gas and (ii) devolatilization with N{sub 2} followed by combustion of obtained char in air. The temperature histories of particles during all stages after introducing in the FB were analyzed. Temperature difference between the burning particle and the FB was defined as a criterion, for comparison. It was shown that the temperature profile depends on the type of the coal and the particle size. The higher temperature difference between the burning particle and the FB was obtained for smaller particles and for lignite (130-180{sup o}C) in comparison to the brown coal (70-130{sup o}C). The obtained results indicated that a primary role in the temperature history of coal particle have the mass and heat transfer through combusting particle. 24 refs., 6 figs., 3 tabs.

Mirko Komatina; Vasilije Manovic; Dragoljub Dakic [University of Belgrade, Belgrade (Serbia and Montenegro). Faculty of Mechanical Engineering

2006-02-01

99

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

100

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

101

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

E-print Network

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

Gruhl, Jim

102

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

NASA Astrophysics Data System (ADS)

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

Plackmeyer, J.

1982-07-01

103

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

NASA Astrophysics Data System (ADS)

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

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

104

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

NASA Technical Reports Server (NTRS)

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.

1981-01-01

105

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

106

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

107

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

SciTech Connect

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

Hongcang Zhou; Baosheng Jin; Rui Xiao; Zhaoping Zhong; Yaji Huang [Nanjing University of Information Science and Technology, Nanjing (China)

2009-04-15

108

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...

109

Parametric studies on catalytic pyrolysis of coal-biomass mixture in a circulating fluidized bed  

Microsoft Academic Search

Pyrolysis is an efficient way of thermally converting biomass into fuel gas, liquid product and char. In this research, pyrolysis\\u000a experiments were carried out in a circulating fluidized bed reactor with a riser diameter of 25 mm and height 1.65 m. The\\u000a biomass used was corn cobs. The experiments were conducted systematically using two level factorial design with temperature\\u000a ranging

Sineenat Rodjeen; Lursuang Mekasut; Prapan Kuchontara; Pornpote Piumsomboon

2006-01-01

110

Material balance in atmospheric fluidized-bed combustion of North Dakota lignite  

Microsoft Academic Search

The distribution of 24 trace and minor elements in the feed and exit streams from a fluidized-bed combustor equipped with a pulse-jet baghouse for particulate control was investigated. Lignite feed was the major source of aluminum, barium, beryllium, iron, sodium and titanium entering the combustor. The limestone feed was the major source of calcium, magnesium and manganese entering the combustor.

R. R. Hall; M. M. McCabe; D. McGrath

1982-01-01

111

(Fluidized bed combustion of high-ash Indian coals): Foreign trip report, January 5, 1988--March 16, 1988  

SciTech Connect

The foreign research assignment at BHEL, Trichy, was undertaken to participate in the ongoing USAID/BHEL joint program in fluidized bed combustion (FBC). As part of this program, an experimental FBC research test facility has been designed, erected and commissioned at BHEL, Trichy, to conduct experiments on the combustion of high-ash Indian coals and coal washery rejects. The data will be used to optimize the design and to select the operational parameters for large scale industrial and utility FBC boilers. ORNL has been providing technical assistance to BHEL since the initiation of the project in November 1983. The US team visited at 10 MW(e) FBC boiler fired with coal washery rejects at the Tata Iron and Steel Company (supplied by BHEL). The tour was very informative and gave the US team a good first-hand perspective of the Indian experience and concerns with FBC technology.

Krishnan, R.P.; Daw, C.S.

1988-03-01

112

Dual Fluidized Bed Biomass Gasification  

SciTech Connect

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

None

2005-09-30

113

Numerical and experimental study of gas–particle radiative heat exchange in a fluidized-bed reactor for steam-gasification of coal  

Microsoft Academic Search

A heat transfer numerical model is developed for the steam-gasification of coal in a fluidized bed contained in a quartz tubular reactor that is directly exposed to concentrated thermal radiation. The Monte Carlo method is applied for solving the radiative exchange within the reactor quartz walls, the bed particles, and the gas phase. The reaction kinetics are described by Langmuir–Hinshelwood

P. von Zedtwitz; W. Lipi?ski; A. Steinfeld

2007-01-01

114

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

115

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

SciTech Connect

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

K.O. Davidsson; L.-E. Aamand; A.-L. Elled; B. Leckner [Chalmers University of Technology, Goeteborg (Sweden). Department of Energy and Environment

2007-12-15

116

COAL CHAR GASIFICATION KINETICS IN A JET-FLUIDIZED BED (COMBUSTION, REACTION, RATE PHENOMENA)  

Microsoft Academic Search

The kinetics of gasification of -10 + 65 mesh coke and coal char with O(,2) and O(,2)-CO(,2) mixtures was studied in a continuous, bench scale, jet-fluidized reactor over a wide range of temperatures (900(DEGREES)C to > 1400(DEGREES)C) and bed depths under atmospheric pressure. The measured specific reaction rates of carbon ranged from 0.01 to 0.1 gram carbon reacting per gram

MING-YUAN KAO

1984-01-01

117

Fuel-Nitrogen Evolution During Fluidized Bed Oxy-Coal Combustion  

NASA Astrophysics Data System (ADS)

FTIR, thermo-gravimetric analysis techniques and molecular modelling were employed to study the effect of CO2 on fuel-nitrogen evolution under oxy-combustion conditions. The main objective is to compare NOx emissions at several molar fractions of O2 using Ar or CO2 as balance gas in a fluidized bed reactor. A char with about 16% N content was prepared by pyrolysis of polyacrylonitrile. This sample facilitated NOx evolution experiments due to the abundance of nitrogen complexes, and aided the identification and quantification of several N species by means ofFTIR. Results indicate that the presence of CO2 enhances NO2 formation. A complementary study was carried out by molecular modelling of the experimental reactions using the Gaussian 03 package. Different heterogeneous and homogeneous interactions between CO2 and char N-species were simulated. The results thus obtained show that the presence of CO2 during combustion can facilitate NCO formation which is a very reactive intermediate species that can be readily oxidized in the gaseous phase.

Sanchez, Astrid; Mondragon, Fanor; Eddings, Eric G.

118

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

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

2001-01-18

119

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

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

2001-07-13

120

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

121

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

PubMed

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

Chindaprasirt, Prinya; Rattanasak, Ubolluk

2010-04-01

122

Development of alterations in hamster distal lung following exposure to fly ash from fluidized bed coal combustion: a morphometric study.  

PubMed

Fly ash (30 mg) from an experimental fluidized bed coal combustor (FBC) was intratracheally instilled once into male Syrian golden hamsters. At 1, 3, 6, 9, or 30 days postadministration, lungs were fixed by intratracheal perfusion and tissues were processed for light and electron microscopic evaluation. Standard point count morphometry, used to analyze distal lung structures, revealed: an increase in volume density (Vv) of noncellular interstitial space at Day 1 which remained elevated at Day 3 but returned to control values subsequently; increased Vv for polymorphonuclear leukocytes (PMNs) and alveolar macrophages in alveolar air space at Day 6; increased Vv of cellular interstitium at Day 9; and increased Vv of noncellular interstitium at Day 30 following exposure. These observations are consistent with the hypothesis that the primary response of the distal lung to particle exposure is recruitment of PMNs and macrophages. When activated, these cells may release substances affecting the cellular and noncellular composition of the interstitial space, leading eventually to increased connective tissue in the interstitium. PMID:3945937

Lantz, R C; Hinton, D E

1986-01-01

123

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

SciTech Connect

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

Chindaprasirt, Prinya [Department of Civil Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen 40002 (Thailand); Rattanasak, Ubolluk, E-mail: ubolluk@buu.ac.t [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Burapha University, Chonburi 20131 (Thailand)

2010-04-15

124

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

125

Coal gasification support studies. Vol. II, Task 2. Studies of fluidized-bed reactors in coal gasification processes. Final report, November 19, 1981-August 15, 1982  

SciTech Connect

The effects of system pressure on solids entrainment and on transport disengaging height (TDH) in gas-solid fluidized beds were experimentally investigated. The specific entrainment rate constant was found to be linearly proportional to the gas density up to a system pressure of 300 psig (a gas density of 1.52 lb/ft/sup 3/). The specific entrainment rate constants from this study were found to lie within the limits of predictions from the existing correlations. TDH was found to increase linearly with both system pressure and gas velocity. The dynamic behavior of gas and solids in an overflow standpipe as a function of several operational variables was also studied. Flow transitions (that is, solids defluidization and gas-flow reversal) were found to be a function of the solids flow rate as well as solids material properties, standpipe aeration, and standpipe geometry. Trends depicting solids defluidization and gas-flow-reversal data are discussed in this report. The effect of distributor design on the tendency of coal char to sinter in fluidized beds was determined. Three distributor configurations were tested at various temperatures, gas velocities, and oxygen concentrations. It was found that there is no difference in using either single- or multiple-nozzle distributors to prevent sintering. A single-nozzle distributor with a concentric annular opening, however, was found to be effective in preventing sintering. The void-gas stripping characteristics of porous solids in standpipes operating in moving packed-bed and fluidized-bed modes were investigated. In this report, the effects of the stripper diameter and stripper-gas injection location on stripping-gas requirements are discussed, and a method of predicting stripping-gas requirements for a porous particle system is presented. 165 figures, 32 tables.

Not Available

1983-06-01

126

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

127

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

SciTech Connect

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

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

1984-04-01

128

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...

129

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

130

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

131

Fluidized Bed Biodenitrification Process.  

National Technical Information Service (NTIS)

A fluidized bed biodenitrification process was operated at bench- scale on simulated high nitrate waste waters. Early results with a cylindrical column were poor but very markedly improved with a change to a conical shaped column. Nitrate reduction effici...

T. M. Wendt, J. P. Heider, A. M. Kaplan

1978-01-01

132

Multilayer coatings by chemical vapor deposition in a fluidized bed reactor at atmospheric pressure (AP\\/FBR-CVD): TiN\\/TaN and TiN\\/W  

Microsoft Academic Search

TiN\\/W and TiN\\/TaN multilayer coatings were deposited on stainless steel by Chemical Vapor Deposition in a Fluidized Bed Reactor at Atmospheric Pressure (AP\\/FBR-CVD). First, the conditions for the deposition of TiN single layers were investigated, both from the experiment and thermochemical estimations. TiN was deposited from TiCl4 and NH3 at temperatures in the range of 750–950 °C. In the synthesis of

J. Perez-Mariano; K.-H. Lau; A. Sanjurjo; J. Caro; J. M. Prado; C. Colominas

2006-01-01

133

TiSiN nanocomposite coatings by chemical vapor deposition in a fluidized bed reactor at atmospheric pressure (AP\\/FBR-CVD)  

Microsoft Academic Search

TiSiN nanocomposite coatings were deposited on stainless steel by chemical vapor deposition in a fluidized bed reactor at atmospheric pressure (AP\\/FBR-CVD) by reaction of TiCl4 and SiCl4 with NH3 at 850 °C. Coatings were characterized by means of GD-OES, XPS and XRD. TiSiN coatings with a Si content of 9 at.% showed a hardness of 28 GPa (the hardness of TiN and

J. Perez-Mariano; K.-H. Lau; A. Sanjurjo; J. Caro; D. Casellas; C. Colominas

2006-01-01

134

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

135

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 ...

136

A simplified model for the combustion of coal in a continuous flow fluidized bed  

E-print Network

where coal burns in an excess of oxygen and that the concentration of carbon monoxide in the flue gas is negligibly small: kl C+ 0 ~CO 2 2 where kl is the reaction rate constant and its value depends on the particle temperature. As in Davidson... where coal burns in an excess of oxygen and that the concentration of carbon monoxide in the flue gas is negligibly small: kl C+ 0 ~CO 2 2 where kl is the reaction rate constant and its value depends on the particle temperature. As in Davidson...

Richardson, Thomas Wade

2012-06-07

137

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

138

Operating Experience of a Coal Fired Fluidized Bed at Georgetown University  

E-print Network

, mechanical dust collector, economizer removal. and baghouse prior to discharging to the stack. FLYASH SYSTEM FUEL SYSTEM As shown i~ Figure 8 flyash from the fluidized To satisfy environmental and aesthetic considera- bed is first passed through a cinder... to the high? efficiency or performance. A coal surge bin is provided above (99.75%) baghouse dust collector. Particles collect- the spreader feeders and a low level indication in ed in the baghouse are pneumatically conveyed to the the surge bin...

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

1980-01-01

139

Co-combustion of rice husk with coal in a cyclonic fluidized-bed combustor (?-FBC)  

Microsoft Academic Search

Thailand is well-endowed with renewable energy resources. In Thailand, rice husk, a by-product of the rice-milling process and one of the most potentially sustainable cultivated biomasses, has an annual energy equivalent of 6.6×107GJ. Using rice husk alone, however, can be problematic, particularly if there is a deficit during the off-season. Coal, the most abundant fossil fuel, has thus been considered

T. Madhiyanon; P. Sathitruangsak; S. Soponronnarit

2009-01-01

140

Granular filtration in a fluidized bed  

SciTech Connect

Successful development of advanced coal-fired power conversion systems often require reliable and efficient cleanup devices which can remove particulate and gaseous pollutants from high-temperature high-pressure gas stream. A novel filtration concept for particulate cleanup has been developed at the Morgantown Energy Technology Center (METC) of the U.S. Department of Energy. The filtration system consists of a fine metal screen filter immersed in a fluidized bed of granular material. As the gas stream passes through the fluidized bed, a layer of the bed granular material is entrained and deposited at the screen surface. This material provides a natural granular filter to separate fine particles from the gas stream passing through the bed. Since the filtering media is the granular material supplied by the fluidized bed, the filter is not subjected to blinding like candle filters. Because only the in-flowing gas, not fine particle cohesive forces, maintains the granular layer at the screen surface, once the thickness and permeability of the granular layer is stabilized, it remains unchanged as long as the in-flowing gas flow rate remains constant. The weight of the particles and the turbulent nature of the fluidized bed limits the thickness of the granular layer on the filter leading to a self-cleaning attribute of the filter. Batch mode filtration performance of the filter was first reported at the Ninth Annual Coal-Fueled Heat Engines, Advanced Pressurized Fluidized-Bed Combustion, and Gas Stream Cleanup Systems Contractors Review Meeting.

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

1995-12-31

141

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

142

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

143

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

144

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

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

2001-10-12

145

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

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

2002-07-12

146

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

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

2001-03-31

147

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

148

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

149

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

150

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

151

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

152

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

153

State of the art of pressurized fluidized bed combustion systems  

SciTech Connect

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

Graves, R.L.

1980-09-01

154

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

Bruce G. Miller; Curtis Jawdy

2000-10-09

155

ENVIRONMENTAL ASPECTS OF FLUIDIZED-BED COMBUSTION  

EPA Science Inventory

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

156

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

E-print Network

fluidized bed combustion In fluidized bed combustion, the combustion takes place in a bed of particles that is being fluidized by means of air blown through the bed from below. The bed is composed of sand, ash, char residue, and, possibly, SO2 sorbent. Fluidized bed combustion may be divided into two main groups

Zevenhoven, Ron

157

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

E-print Network

fluidized bed combustion In fluidized bed combustion, the combustion takes place in a bed of particles that is being fluidized by means of air blown through the bed from below. The bed is composed of sand, ash, char residue, and, possibly, SO2 sorbent. Fluidized bed combustion may be divided into two main groups

Laughlin, Robert B.

158

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

SciTech Connect

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

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

1980-12-01

159

Granular filtration in a fluidized bed  

SciTech Connect

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

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

1996-12-31

160

Parametric performance studies on fluidized-bed heat exchangers  

NASA Astrophysics Data System (ADS)

The performance of single and multistage shallow fluidized beds for possible application to the recovery of heat from sources as waste heat, and coal combustion or coal gasification were investigated. The following tests are investigated: (1) the effects of fouling due to liquid condensate in the gas stream of fluidized beds which are staged using baffle plates; and (3) the effects of different heat exchanger surface geometries. The conditions fouling by a liquid condensate are selected. Modifications are made to the fluidized bed heat exchanger facility for the fouling experiments.

Stoffler, R. C.

1981-10-01

161

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

162

Fluidized bed combustion  

SciTech Connect

The invention relates to fluidized bed combustors that might tilt in use so that the depth of the bed progressively changes across its width. Air is supplied from two or more sources and means are provided to vary the flow from the sources as the bed tilts so that the air supplied to the portion of the bed of increased depth is increased relatively to the air supplied to the portion of the bed of lesser depth.

Hodgkin, A.F.

1980-12-16

163

Staged fluidized bed  

DOEpatents

Method and apparatus 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, Richard G. (Livermore, CA)

1984-01-01

164

Sulfation phenomena in fluidized bed combustion systems  

Microsoft Academic Search

Fluidized bed combustors (FBCs) are noted for their ability to capture SO2 in situ via direct reaction with Ca-based sorbents. However, despite more than 30 years of intensive study of sulfation processes in atmospheric FBC boilers and numerous laboratory studies, there are still many uncertainties and disagreements on the subject. In particular, the mechanisms of the sulfation reaction are still

E. J. Anthony; D. L. Granatstein

2001-01-01

165

Pulmonary toxicity associated with fly ash from fluidized bed coal combustion. II. Cellular morphometry of distal lung following a single intratracheal instillation.  

PubMed

Fly ash from an experimental fluidized bed coal combustor (FBC) was intratracheally instilled (once) into male Syrian golden hamsters at concentrations of 0 (control), 3, 10, 30, and 100 mg/animal. Thirty days postadministration, lungs were fixed by intratracheal perfusion, and tissues were processed for electron microscopic evaluation. Standard point count morphometry was used to analyze distal lung structures. Significant differences were found in volume density of noncellular interstitial space, with this compartment being increased in a dose-dependent manner. Volume density, numerical density, and average cellular volume of distal lung cells revealed no significant differences between treated and control animals. In addition, diffusion capacity and air-blood barrier thickness were not significantly altered in treated animals. The absence of cellular change at 30 days postexposure suggests a residual effect on noncellular interstitium, which may implicate fibrosis. PMID:6464021

Lantz, R C; Hinton, D E

1984-08-01

166

Role of Additives in Controlling Agglomeration and Defluidization During Fluidized Bed Combustion of High-Sodium, High-Sulphur Low-Rank Coal  

NASA Astrophysics Data System (ADS)

Four additives have been tested to determine their effectiveness in controlling ash deposition, agglomeration and defluidization under circulating fluidized bed combustor conditions. Gibbsite was found to be most effective. The evidence obtained from the various analytical techniques suggests that depending on the type of additive used, interference in the process of ash deposition may be due to either a chemical reaction or physical dilution. These interactions apparently occur at the surface of burning char particles. Although previous investigations have identified clays to be effective in sodium capture, care must be taken in selection of clay additives since the mineralogical composition of the clays appears to play a major role in the extent of deposit formation control. Gibbsite and the clays have demonstrated potential for in-situ sodium capture which may facilitate use of low-rank coals in advanced FBC-based power generation plants.

Linjewile, Temi M.; Manzoori, Alan R.

167

Biparticle fluidized bed reactor  

DOEpatents

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

Scott, C.D.

1993-12-14

168

Biparticle fluidized bed reactor  

DOEpatents

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

Scott, Charles D. (Oak Ridge, TN)

1993-01-01

169

Biparticle fluidized bed reactor  

DOEpatents

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

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

1995-01-01

170

Biparticle fluidized bed reactor  

DOEpatents

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

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

1996-01-01

171

Biparticle fluidized bed reactor  

DOEpatents

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

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

1995-04-25

172

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

173

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

174

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

SciTech Connect

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

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

1995-03-01

175

Automated on-line determination of PPB levels of sodium and potassium in low-Btu coal gas and fluidized bed combustor exhaust by atomic emission spectrometry  

SciTech Connect

The Morgantown Energy Technology Center (METC), US Department of Energy, is involved in the development of processes and equipment for production of low-Btu gas from coal and for fluidized bed combustion of coal. The ultimate objective is large scale production of electricity using high temperature gas turbines. Such turbines, however, are susceptible to accelerated corrosion and self-destruction when relatively low concentrations of sodium and potassium are present in the driving gas streams. Knowledge and control of the concentrations of those elements, at part per billion levels, are critical to the success of both the gas cleanup procedures that are being investigated and the overall energy conversion processes. This presentation describes instrumentation and procedures developed at the Ames Laboratory for application to the problems outlined above and results that have been obtained so far at METC. The first Ames instruments, which feature an automated, dual channel flame atomic emission spectrometer, perform the sodium and potassium determinations simultaneously, repetitively, and automatically every two to three minutes by atomizing and exciting a fraction of the subject gas sample stream in either an oxyhydrogen flame or a nitrous oxide-acetylene flame. The analytical results are printed and can be transmitted simultaneously to a process control center.

Haas, W.J. Jr.; Eckels, D.E.; Kniseley, R.N.; Fassel, V.A.

1981-01-01

176

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

177

Decreased gas consumption of a fluidized bed furnace  

NASA Astrophysics Data System (ADS)

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

Chen, Yong-Chwang

1993-10-01

178

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

179

Effects of Immersed Surfaces on the Combustor Efficiency of Small Scale Fluidized Beds  

Microsoft Academic Search

In this study, effects of the different types of heat exchanger surfaces on the second law efficiency of a small-scale circulating fluidized bed (CFB) combustor are analyzed and the results are compared with the bubbling fluidized bed coal combustor effectiveness values. Using a previously developed simulation program, combustor efficiency and entropy generation values are obtained at different operation velocities at

Afsin GUNGOR; Nurdil ESKIN

180

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

181

Description, applications and numerical modelling of bubbling fluidized bed combustion in waste-to-energy plants  

Microsoft Academic Search

The use of the fluidized bed combustor (FBC) has increased. It began in the 20th century as coal combustion and gasification, which then developed into catalytic reactions. Only recently, the application field has been extended to the incineration of biomass and pre-treated waste, for either power generation or waste disposal. The success of fluidized bed combustion is due to high

S. Ravelli; A. Perdichizzi; G. Barigozzi

2008-01-01

182

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

183

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

184

An experimental and modeling study of the contribution of coal ash to SO 2 capture in fluidized bed combustion  

Microsoft Academic Search

The process of sulfur self-retention (SSR) occurs as a result of the reactions between the mineral matter in coal ash and the SO2 evolved during coal combustion. Consequently, the emission of SO2 may be significantly reduced. The results of experimental investigations and modeling of SSR is presented in this work. The transformations of sulfur forms during devolatilization are taken into

Borislav Grubor; Vasilije Manovic; Simeon Oka

2003-01-01

185

IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 8, NO. 2, MARCH 2000 247 A Model of a Bubbling Fluidized Bed Combustor  

E-print Network

of a Bubbling Fluidized Bed Combustor Oriented to Char Mass Estimation Sergio Bittanti, Senior Member, IEEE Prandoni Abstract--Fluidized bed techniques are employed in coal com- bustion power plants, because- namical difference between fluidized beds and normal combustion chambers, is that the former

Campi, Marco

186

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

Microsoft Academic Search

A fluidized bed pyrolysis reactor system was designed, constructed, and tested at reactor pressures less than atmospheric using mined and crushed oil sands from the Whiterocks deposit of Utah. A 6.0 inch ID fluidized bed reactor was fed oil sand of 7% bitumen saturation on a continuous basis while maintaining a bed height of approximately 12 inches. Spent sand was

1992-01-01

187

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

188

Fluidized bed nuclear fission reactor  

Microsoft Academic Search

For the further development of nuclear fission reactors, the feasibility of a new concept is evaluated. It concerns a fluidized bed reactor in which carbon particles with a uranium core are fluidized and cooled by a high velocity pressurized helium flow. Nuclear reaction takes place if the bed is in fluidized conditions at a void fraction above 80% and it

T. H. J. J. Van Der Hagen; H. Van Dam

1996-01-01

189

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

190

Fluidized-Bed Reactor System  

NASA Technical Reports Server (NTRS)

Gas pyrolysis in hot fluidized beds minimized by use of selectively filtered radiation and parabolic cavity. Reactor is parabolic cavity of two or more axes in which light emanating from one axis bounces off walls of cavity and passes through object axis to heat sample.

Morrison, A. D.

1985-01-01

191

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

192

Utilization of ash from fluidized bed boilers  

SciTech Connect

Combustion ash from a fluidized bed combustion (FBC) boiler contains not only carbon, but also silica alumina, quicklime as a sorbent, and a calcium sulfate by-product. These substances react chemically during fluidized bed combustion, and with the addition of water, they start an ettringite reaction and solidify. We determined the conditions necessary for producing hard solids through the study of the composition, curing methods, and characteristics of the solidified ash. We then used two types of road base material, crushed stone and solidified ash from an FBC boiler, to construct a test road at a site with a great deal of heavy traffic. Construction began in 1985, and since then, periodic tests have been performed to evaluate the performance of the road base materials. The testing of the manufacturing techniques centered on the amount and manner that water was added to the mixture and the curing methods of the mixture. Additional testing focused on the handling of the ash powder, the mixtures, and the solidified ash. Since 1991, under the sponsorship of MITI, the Center for Coal Utilization, in conjunction with Naruto Salt Mfg., Ltd., Nippon Hodo Co., Ltd., and Kawasaki Heavy Industries, Ltd., has used the referenced results to undertake a joint research and development project aimed at the eventual practical application of the technology. In 1993, a pilot facility to solidify ash with the fluidized bed boiler of 75 t/h capacity was completed. At present, all the discharged ash from the pilot facility is being solidified, and experiments on solidification and road base application techniques are underway. Actual road base tests are also in progress, and we are continuing research to meet the national certification requirements for road base materials.

Takada, Tomoaki [Kawasaki Heavy Industries Co., Ltd., Akashi (Japan)

1994-12-31

193

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...

194

Review of fluidized bed combustion technology in the United States  

SciTech Connect

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

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

1984-01-01

195

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

SciTech Connect

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

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

2013-09-30

196

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

197

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....

198

Parametric performance studies on fluidized-bed heat exchangers  

NASA Astrophysics Data System (ADS)

The performance of single and multistage shallow fluidized beds is investigated for possible application to the recovery of heat from sources such as waste heat, and coal combustion or coal gasification. Tests are conducted to (1) investigate the effects of fouling due to liquid condensate in the gas stream on fluidized bed heat exchanger performance, (2) investigate the performance of fluidized beds which are staged using baffle plates, and (3) investigate the effects of different heat exchanger surface geometries. Work is progressing in selecting the conditions for that portion of the program involving fouling by a liquid condensate, and in modifying the fluidized bed heat exchanger facility for the fouling experiments. Preliminary tests were conducted with water vapor injection. Water vapor and glycerol vapor were chosen as the condensates. The results are summarized as follows: (1) heat exchanger performance is seriously degraded by condensation when the dew point temperature exceeds the heat exchanger wall temperature; and (2) the performance decrease occurs as a result of particle adherence to the heat exchanger surface and not as a result of particle agglomeration.

Stoeffler, R. C.

1982-01-01

199

Capacitively-Heated Fluidized Bed  

NASA Technical Reports Server (NTRS)

Fluidized-bed chamber in which particles in bed are capacitively heated produces high yields of polycrystalline silicon for semiconductor devices. Deposition of unrecoverable silicon on chamber wall is reduced, and amount of recoverable silicon depositing on seed particles in bed is increased. Particles also have a size and density suitable for direct handling without consolidation, unlike silicon dust produced in heated-wall chambers.

Mchale, E. J.

1982-01-01

200

Fluidized-Bed Reactor With Zone Heating  

NASA Technical Reports Server (NTRS)

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

Iya, Sridhar K.

1989-01-01

201

Fluidized bed regenerators for Brayton cycles  

NASA Technical Reports Server (NTRS)

A recuperator consisting of two fluidized bed regenerators with circulating solid particles is considered for use in a Brayton cycle. These fluidized beds offer the possibility of high temperature operation if ceramic particles are used. Calculations of the efficiency and size of fluidized bed regenerators for typical values of operating parameters were made and compared to a shell and tube recuperator. The calculations indicate that the fluidized beds will be more compact than the shell and tube as well as offering a high temperature operating capability.

Nichols, L. D.

1975-01-01

202

Fluidized bed regenerators for Brayton cycles  

NASA Technical Reports Server (NTRS)

A recuperator consisting of two fluidized bed regenerators with circulating solid particles is considered for use in a Brayton cycle. These fluidized beds offer the possibility of high temperature operation if ceramic particles are used. Calculations of the efficiency and size of fluidized bed regenerators for typical values of operating parameters have been made and compared to a shell and tube recuperator. The calculations indicate that the fluidized beds will be more compact than the shell and tube as well as offering a high temperature operating capability.

Nichols, L. D.

1975-01-01

203

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

204

Plasma enhanced chemical vapor deposition of TiO 2 films on silica gel powders at atmospheric pressure in a circulating fluidized bed reactor  

Microsoft Academic Search

Anatase TiO2 thin films were deposited on silica gel powders by plasma enhanced chemical vapor deposition (PECVD) method in a circulating fluidized bed (CFB) reactor using TTIP [Ti(O-i-C3H7)4] and oxygen without any post-treatment. The optimum solid circulation rates were determined for the stable He-plasma glow discharge with He fluidizing gas. The optimum deposition conditions of TiO2 thin films by PECVD

Gook Hee Kim; Sang Done Kim; Soung Hee Park

2009-01-01

205

Solar heated fluidized bed gasification system  

SciTech Connect

This solar-heated gasification system avoids the problems inherent in other solar processes (such as blackened solar-input windows and overheated zones on the reactor walls) by heating the fluidizing gas and steam in a solar-heat absorption zone before they enter the reactor. Energy to heat the gas and steam concentrates in high-heat-capacity refractory honeycomb that surrounds the fluidized-bed reactor zone. Solar concentrators focus the solar energy on the honeycomb through a solar window. The reaction zone is also heated directly and uniformly by thermal contact of the ceramic honeycomb with the walls of the reactor. The reactor handles such solids as coal and biomass.

Frosch, R.A.; Qader, S.A.

1981-09-22

206

Reduction of particulate carryover from a pressurized fluidized bed  

NASA Technical Reports Server (NTRS)

A bench-scale pressurized fluidized bed combustor (PFBC) constructed with a conical shape to reduce the particulate carryover is examined. The combustor was fed coal and limestone with the coal to air ratio varying from 0.033 to 0.098 (all lean) and the coal to limestone ratio varying from 0.06 to 0.36. Two cone angles were used and it is shown that the average particulate carryover of 2.5 grains/SCF is appreciably less than cylindrical fluidized bed combustors. In addition the carryover was correlated by multiple regression analysis to yield the dependence on bed depth and hence the collection efficiency, which was 20%. Finally, a comparison with a model indicated that the exhaust port may be below the transport disengaging height for most of the tests showing that further improvements could be achieved by increasing the freeboard height of the exhaust port above the bed.

Patch, R. W.

1979-01-01

207

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

208

Modeling of fluidized bed silicon deposition process  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

209

Rapid carburizing with natural gas in a fluidized bed  

Microsoft Academic Search

1.Carburizing with combustion of natural gas in a fluidized bed with a stationary catalyst and air input coefficient a<0.25 is not possible because the GIAP-3 catalyst is deactivated by soot.When a=0.26–0.29 the carburizing capacity of the atmosphere is insufficient to carburize carbon and alloy steels.2.In order to increase the carbon potential of the atmosphere with a=0.26–0.29, 15–25% gas-carburizer must be

T. A. Pumpyanskaya; V. A. Vinokurov; A. P. Baskakov

1972-01-01

210

Catalytic Cracking of Cottonseed Oil on Fixed-fluidized Bed Reactor: Product Distribution and Analysis of the Gasoline Fraction  

Microsoft Academic Search

Gasoline samples resulting from cottonseed oil catalytic cracking on a fixed-fluidized bed were analyzed to give the carbon number distribution of paraffinic, isoparaffinic, olefinic, naphthenic, and aromatic components using PIONA analysis. Cottonseed oil catalytic cracking was studied on a fixed-fluidized bed reactor under atmospheric pressure in order to analyze temperature influence on the gasoline composition. Cracking temperatures were from 430

H. Li; B. X. Shen; J. C. Kabalu; N. Mominou

2010-01-01

211

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

NASA Astrophysics Data System (ADS)

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

Desai, Chetan Jitendra

212

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

213

Fluidized-Bed Reactor and Hot Gas Cleanup Facility  

SciTech Connect

As part of the Morgantown Energy Technology Center`s (METC) Advanced Gasification and Hot Gas Cleanup Facility, a 907 kg (1 ton) coal-per-day (10-inch inside diameter) jetting fluidized-bed gasifier provides realistic fuel gas for testing and developing high-temperature, high-pressure components and processes in a reducing (gasification) and oxidizing (combustion) environment. Operated mainly as a gasifier, the 0.25-m (10-inch) diameter reactor produces up to 227 kg/hr (500 lb/hr) of coal gas at 866 K (1,100{degrees}F) and 30 atmospheres (425 psig) for downstream testing. The raw coal gas is sampled for major and trace species and sent to a filter vessel capable of operating at 894 K (1,150{degrees}F) and 20 atmospheres (290 psig) of pressure. After particulate removal, the gas can be independently controlled to up to five sampling or reaction vessels including fluid-bed desulfurization, transport desulfurization, chloride, alkali, or other contaminant removal or recovery processes. The fluid-bed desulfurizer is capable of being isolated, purged, and exposed to an oxidizing environment for sorbent regeneration or other oxidation reaction. Isokinetic hazardous air pollutant (HAPS) monitoring is provided at the upstream and downstream of particulate removal. Over the post three years, 1,200 hours of operation have been completed in support of six separate Cooperative Research and Development Agreements (CRADAs). These research agreements have been in the areas of candle filters and materials testing, direct sulfur recovery from sorbent regeneration tail gases, and gasifier development.

Rockey, J.M.

1996-12-31

214

Drying of solids in fluidized beds  

SciTech Connect

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

Kannan, C.S.; Thomas, P.P.; Varma, Y.B.G. [Indian Inst. of Tech., Madras (India). Dept. of Chemical Engineering

1995-09-01

215

State of Fluidized Bed Combustion Technology  

E-print Network

directly in fluidized beds while taking advantage of low furnace temperatures and chemical activity within the bed to limit SO 2 and NOx emissions, thereby eliminating the need for stack gas scrubbing equipment. The excellent heat transfer characteristics...

Pope, M.

1979-01-01

216

TECHNOLOGY OVERVIEW: CIRCULATING FLUIDIZED-BED COMBUSTION  

EPA Science Inventory

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

217

FLUIDIZED-BED COMBUSTION TECHNOLOGY OVERVIEW  

EPA Science Inventory

The report reviews fluidized-bed combustion (FBC) technology development through 1979, specifying the work of governmental agencies and individual investigators, highlighting key technical issues, and documenting the current degree of FBC commercialization....

218

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

219

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

SciTech Connect

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

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

1980-10-01

220

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

221

COMPUTATIONAL MODELING OF CIRCULATING FLUIDIZED BED REACTORS  

SciTech Connect

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

Ibrahim, Essam A

2013-01-09

222

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

223

Parametric performance studies on fluidized-bed heat exchangers. Task 1: Fouling characteristics  

NASA Astrophysics Data System (ADS)

Analyses and experiments are being performed to investigate the heat transfer performance of single and multistage shallow fluidized beds for application to the recovery of heat from sources such as waste heat, and coal combustion or coal gasification. Tests were conducted to investigate the effects of liquid condensate fouling on fluidized bed heat exchanger performance. Liquid condensates used in these tests were water and glycerol (which is more viscous than water). The tests showed that fluidized bed heat exchanger performance is degraded by condensation within the bed and the degradation is caused by bed particles adhering to the heat exchanger surface, not by particle agglomeration. Liquid condensate did not continuously build up within the bed. After a period of dry out, heat transfer equal to that obtained prior to condensation was again obtained.

Stoeffler, R. C.

1982-09-01

224

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

225

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

SciTech Connect

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

Not Available

1980-01-01

226

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

SciTech Connect

Ventilation air methane (VAM) accounts for 60-80% of the total emissions from underground coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible. 17 refs., 3 figs., 1 tab.

Changfu You; Xuchang Xu [Tsinghua University, Beijing (China). Key Laboratory for Thermal Science and Power Engineering of Ministry of Education

2008-04-01

227

Expansion of three-phase fluidized bed  

SciTech Connect

This article reports on experimental studies of the expansion of a three-phase fluidized bed, used in hydroprocessing heavy petroleum residual stocks, in relation to the catalyst bed height and the linear velocities of liquid and gas. The height of the settled bed of catalyst was varied from 200 to 1000 mm. The rising gas-liquid flow fluidizes and expands the catalyst bed. The height of the three-phase fluidized bed in the column with transparent walls was determined visually by passing a light beam through the column. It is determined that the dependence of the height of the spray zone on the gas velocity is due to the fact that the gas flow emerges from the upper level of the fluidized bed in the form of a jet, capturing solid-phase particles and ejecting them from the bed with an energy that is proportional to the linear velocity of the gas.

Razumov, I.M.; Dukel'skii, G.Y.; Kurganov, V.M.; Rossina, M.R.; Terekhov, N.I.

1984-01-01

228

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

229

Fluidized bed gasification of agricultural residue  

E-print Network

of par- ticle size. The shrinking core model was used to approxi- mate the kinetics of the reaction. Cellulose was pyrolyzed at temperatures up to 750 F (672 K) in a fluidized bed reactor by Barooah and Long (1976). Liu and Serenius (1976) utilized a... of par- ticle size. The shrinking core model was used to approxi- mate the kinetics of the reaction. Cellulose was pyrolyzed at temperatures up to 750 F (672 K) in a fluidized bed reactor by Barooah and Long (1976). Liu and Serenius (1976) utilized a...

Groves, John David

2012-06-07

230

chaodyn/9502021 Dynamical simulation of fluidized beds --hydrodynamically  

E-print Network

chao­dyn/9502021 Dynamical simulation of fluidized beds -- hydrodynamically interacting granular Green Street, Urbana, IL61801­3080, USA z Abstract A numerical simulation of a gas­fluidized bed, illustrative of dynamical phase transitions [11--13]. In an experiment on fluidized beds, we prepare a vessel

Ichiki, Kengo

231

Dynamics of a shallow fluidized bed Lev S. Tsimring,1  

E-print Network

Dynamics of a shallow fluidized bed Lev S. Tsimring,1 Ramakrishna Ramaswamy,2 and Philip Sherman1 1 The results of the experimental study of the dynamics of a shallow fluidized bed are reported. The behavior Fluidized beds are widely used in industry for mixing solid particles with gases or liquids 1 . In most

Hasty, Jeff

232

Dynamical simulation of fluidized beds -hydrodynamically interacting granular particles  

E-print Network

Dynamical simulation of fluidized beds - hydrodynamically interacting) Abstract A numerical simulation of a gas-fluidized bed is performed without int* *roduc-13]. In an experiment on fluidized beds, we prepare a vessel containing granular * *particles and impose a gas flow

Ichiki, Kengo

233

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

234

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

SciTech Connect

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

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

1992-06-01

235

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

236

138 Chemical Engineering Education FLUIDIZED BED  

E-print Network

of the experiment is to place a pro- tective coating on a metal object by first heating it in a hot- air stream and then dipping it into a fluidized bed of thermo- plastic powder. The powder is contained within a clear plas of the engi- neering measurements of flowrate, temperature, pressure, and coating thickness. They design

Hesketh, Robert

237

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

238

Fluidized bed coating in food technology  

Microsoft Academic Search

Originally developed as a pharmaceutical technique, fluidized bed coating is now increasingly being applied in the food industry to tune the effect of functional ingredients and additives. Main benefits of such miniature packages, called microcapsules, include increased shelf life, taste masking, ease of handling, controlled release, improved aesthetics, taste and color. However, compared with a pharmaceutical technologist, a food technologist

K. Dewettinck; A. Huyghebaert

1999-01-01

239

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...

240

Prediction of wear in a fluidized bed  

SciTech Connect

The formulation of a procedure to model wear of surfaces exposed to a fluidized bed is discussed. A stochastic methodology adapting kinetic theory of gases to granular flows is used to derive an impact wear model. It uses a single-particle wear model to account for impact wear from all possible particle collisions. An adaptation of an empirical 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 solution of the wear expressions, are found using a computer code to model the fluidized bed hydrodynamics. Additional parameters describing the contact between fluidized particles and the wearing surface are determined with an optimization procedure based on wear measurements. The modeling procedure was applied to various bubbling and turbulent fluidized beds with single-tube and tube bundle configurations. Quantitative agreement between measured and predicted wear rates was exhibited with some exceptions for local wear predictions. Improvements in both the analytic wear expression and the computer code used to model bed hydrodynamics are needed to accurately predict local wear, thus providing true predictive capability.

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

1991-09-01

241

The prediction of wear in fluidized beds  

SciTech Connect

A procedure is formulated to model impact and abrasion wear of surfaces exposed to a fluidized bed. A methodology adapting a single-particle wear model and the kinetic theory of gases to granular flows is used to develop a model accounting for impact wear from all possible particle collisions. Abrasive wear is modeled using a single-particle abrasion model adapted to describe the effects of many abrading particles. Parameters describing granular flow are necessary for evaluation of the resulting wear expressions. They are determined by numerical solution of the conservation equations describing fluidized-bed hydrodynamics. Additional parameters appear in the wear expressions which describe the contact between individual fluidized particles and the wearing surface. These are determined by an optimization procedure which minimizes error between predicted and measured wear rates. 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 prediction in fluidized beds.

Rogers, W.A. [EG and G Technical Services of West Virginia, Inc., Morgantown, WV (United States)

1995-05-01

242

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

243

Fluidization quality analyzer for fluidized beds  

SciTech Connect

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

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

1995-07-25

244

Fluidized bed biofilm reactor for wastewater treatment  

Microsoft Academic Search

The fluidized bed biofilm reactor (FBBR) represents a recent innovation in biofilm processes. Immobilization of microorganisms on the small, fluidized particles of the medium results in a high reactor biomass holdup which enables the process to be operated at significantly higher liquid throughputs with the practical absence of biomass wash-out. The process intensification (i.e., a reduction in process size while

Wen K. Shieh; John D. Keenan

245

Improved Fluidized-Bed Gas Injector  

NASA Technical Reports Server (NTRS)

Gas-injection cone in fluidized-bed reactor for coating particles with silicon or carbon cooled and protected from abrasion by stream of gas flowing over surface of cone. Hot particles entering reaction zone are coated with silicon or carbon supplied by thermal decomposition of suitable gas injected into reaction zone.

Hogle, R. A.

1983-01-01

246

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...

247

Impact of the Circulating Fluidized Bed Riser on the Performance of a Loopseal Nonmechanical Valve  

Microsoft Academic Search

Most advanced coal-fuel power systems require the transfer and control of solids between two or more vessels. In many instances, the key to a successful process operation is how well the solids transfer and control system has been designed. This is particularly true in a transport gasifier and circulating fluidized bed (CFB) combustors, which are dependent upon the rapid and

Esmail R. Monazam; Lawrence J. Shadle; Joseph S. Mei

2007-01-01

248

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

PubMed

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

Barto?ová, Lucie; Klika, Zden?k

2014-07-01

249

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

E-print Network

the use of a baghouse. The baghouse filters 99+% of the particulate out of the flue gases. Construction Schedule - It is important to note that if a decision to proceed was made, at least 48 months lead time would be required for a coal fired by... the use of a baghouse. The baghouse filters 99+% of the particulate out of the flue gases. Construction Schedule - It is important to note that if a decision to proceed was made, at least 48 months lead time would be required for a coal fired by...

Mesko, J. E.

1980-01-01

250

NYU-DOE Pressurized Fluidized Bed Combustor Facility  

SciTech Connect

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

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

1983-01-01

251

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

252

Dynamics of a shallow fluidized bed.  

PubMed

The results of the experimental study of the dynamics of a shallow fluidized bed are reported. The behavior of granular material is controlled by the interplay of two factors--levitation due to the upward airflow, and sliding back due to gravity. Near the threshold of instability, the system shows critical behavior with remarkably long transient dynamics. The experimental observations are compared with a simple cellular automata model. PMID:11970652

Tsimring, L S; Ramaswamy, R; Sherman, P

1999-12-01

253

Numerical Modelling of Circulating Fluidized Beds  

Microsoft Academic Search

The development of the multi-phase flow algorithm MIPSA (Multi-InterPhase Slip-Algorithm) within a two-dimensional Computational Fluid Dynamics (CFD) code called CASCADE is summarized with its application to the modelling of lean phase circulating fluidized beds. The well-known interPhase Slip Algorithm (IPSA) technique for handling the presence of particles in an air stream is modified and extended, to handle explicitly a range

M. K. Patel; K. Pericleous; M. Cross

1993-01-01

254

Fluidized-bed biological nitrogen removal  

SciTech Connect

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

Hosaka, Yukihisa; Minami, Takeshi; Nasuno, Sai (Bureau of Sewage, Tokyo (Japan))

1991-08-01

255

Particle pressures in fluidized beds. Annual report  

SciTech Connect

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

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

1994-03-01

256

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

257

TECHNOLOGY ASSESSMENT REPORT FOR INDUSTRIAL BOILER APPLICATIONS: FLUIDIZED-BED COMBUSTION  

EPA Science Inventory

The report gives results of an assessment of the applicability of atmospheric fluidized-bed combustion (AFBC) to industrial boilers. It is one of a series of reports to aid in determining the technological basis for a New Source Performance Standard for air pollutant emissions fr...

258

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

EPA Science Inventory

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

259

Pressurized Fluidized Bed Combustion of Sewage Sludge  

NASA Astrophysics Data System (ADS)

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

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

260

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

261

Environmental remediation with products of fluidized bed combustion  

SciTech Connect

Commercialization of fluidized bed combustion (FBC) technology could be enhanced by increased utilization of FBC products (ash). In the US, coal combustion products (CCP) are not hazardous under RCRA and are regulated as residual waste by the states. The composition of CCP from fluidized beds is primarily determined by the inorganic constituents in coal, the sorbent reaction products and the unreacted sorbent. The combustion system and the inclusion of other fuels may also affect the chemical composition, physical properties and leaching behavior. The alkalinity of the FBC material, residual lime and pozzolanic properties are desirable characteristics for use in soil stabilization and mine reclamation. At reclaimed surface coal mines, placement of CCP is intended to reduce the amount of acid mine drainage (AMD) produced at such sites. Neutralization, inhibition of acid forming bacteria, encapsulation of the pyrite or water diversion are believed to be the mechanisms facilitated by the alkaline material. Comparison of water quality, before and after injection of a grout composed of FBC ash and water indicated small increases in pH and decreases in acidity at discharge points. The concentrations of calcium and magnesium in water samples generally increased compared to background levels. The average concentration of trace elements (arsenic, cobalt, copper, nickel and zinc) was slightly elevated in the injection areas, but in down dip and discharge water samples were comparable to background levels. Over a four year period, the average acidity in the injected area decreased by approximately 30%, a value similar to another site where a mixture of class F fly ash and cement was injected. Although coal mine remediation is a beneficial environmental use of FBC products, its effectiveness may be related to the amount of FBCB used and the method of emplacement.

Kim, A.G.

1999-07-01

262

Bed material agglomeration during fluidized bed combustion. Final report  

SciTech Connect

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

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

1996-01-01

263

Hydrodynamic Characterization of 3D Fluidized Beds Using Noninvasive Techniques.  

E-print Network

??Fluidized beds are useful processing systems that are employed by many industries for their relatively unique operating properties. Low pressure drops, uniform temperature distributions, and… (more)

Drake, Joshua

2011-01-01

264

Analysis of statistical quantities in simulation of fluidized beds Kengo Ichiki* & Hisao Hayakaway  

E-print Network

Analysis of statistical quantities in simulation of fluidized beds basedeonlthesmodel, particles are trea* *ted as a fluid [5-10]. These models of fluidized beds proposed model of fluidized beds, where h* *ydrodynamic interac

Ichiki, Kengo

265

Behavior of fluidized beds similar to equilibrium states Kengo Ichiki* & Hisao Hayakaway  

E-print Network

Behavior of fluidized beds similar to equilibrium states Kengo) Abstract Systematic simulations are carried out based on the model of fluidized* * beds and the bubbling phase. We find the close relations b* *etween the averaged behaviors in fluidized beds

Ichiki, Kengo

266

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

267

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

SciTech Connect

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

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

1997-12-31

268

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

269

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

270

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

271

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

272

Fluidized-Bed Cleaning of Silicon Particles  

NASA Technical Reports Server (NTRS)

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

Rohatgi, Naresh K.; Hsu, George C.

1987-01-01

273

Mathematical modeling of fluidized bed reactors  

E-print Network

of Department) August 1985 ABSTRACT Mathematical Modeling of Fluidized Bed Reactors. (August 1985) Nilufer Havva Nasif, B. S. , M1ddle East Technical University, Ankara-Turkey Chairman of Adv1sory Committee: Dr. Dragomir B. Bukur The effects of bubble... of the emulsion phase gas, and by taking into account the bubble size variation with height. The two phase models of Davison and Harrison, the Bubbling Bed Model, and the Countercurrent Backmixing Model, w1th bubble size variation with height, have been used...

Nasif, Nilufer Havva

2012-06-07

274

Pyrolysis reactor and fluidized bed combustion chamber  

DOEpatents

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

Green, Norman W. (Upland, CA)

1981-01-06

275

Heat and mass transfer in fixed and fluidized beds  

Microsoft Academic Search

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

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

1985-01-01

276

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

277

Mixing of secondary gas injection in a bubbling fluidized bed  

Microsoft Academic Search

In this work, three-dimensional numerical simulations with the aim of investigating the mixing of secondary gas in a bubbling fluidized bed are performed. Single and multiple horizontal gas jet injections into a small scale rectangular bubbling fluidized bed are studied. A tracer gas is introduced through the jet orifice to study the gas mixing in the system. Both transient and

Tingwen Li; Konstantin Pougatch; Martha Salcudean; Dana Grecov

2009-01-01

278

Hydrodynamic Characterization of 3D Fluidized Beds Using Noninvasive Techniques  

Microsoft Academic Search

Fluidized beds are useful processing systems that are employed by many industries for their relatively unique operating properties. Low pressure drops, uniform temperature distributions, and high heat\\/mass transfer rates occur through the action of vertical gas injection into a column of solid particles. Although these properties give fluidized beds great advantages over other processing systems, the hydrodynamic characterization of fluidized

Joshua Drake

2011-01-01

279

Improved Fluidized-Bed Reactor With Horizontal Staging  

NASA Technical Reports Server (NTRS)

Design of fluidized-bed reactor containing multiple, horizontally arrayed stages offers advantages over present multistage fluidized bed reactors with horizontal, vertical, or slanted stacking. In new reactor, solids proceed from one stage to next by flow over weir. Design promotes conservation of energy and optimization of flows and residence times.

Sullivan, Thomas A.

1992-01-01

280

Physical separation of particles in magnetized fluidized beds  

Microsoft Academic Search

Magnetized fluidized bed stability is defined using relative amplitudes of pressure fluctuations. It is shown that transition velocities exist for different degrees of bed stability. Experimental results show that magnetically stabilized fluidized beds can be used to effect separation of particles by differences in particle penetration depth and settling velocity.

O. Harel; W. Resnick; Y. Zimmels

1990-01-01

281

The combustion rate of volatiles in a fluidized bed combustor  

SciTech Connect

The combustion rate of coal volatiles within the dense phase is controlled by the rate of mixing with oxygen from the fluidizing air. Multiple discrete diffusion flame and plume models for volatiles combustion assume that this rate is determined by a radial dispersion coefficient, which characterizes the lateral mixing rate at the boundary between a plume of volatiles rising through the bed and the adjacent oxygen-containing region. The radial dispersion of tracer gas has been resolved into plume meandering and turbulent components, and the combustion rate of volatiles was assumed to be controlled by the turbulent dispersion coefficient. This paper investigates the applicability of the plume model with these turbulent dispersion coefficients to the prediction of the combustion rate of volatiles within the bed. Tracer gas and combustion experiments were performed at 850--900 C in the same fluidized bed. Nitrogen tracer gas and volatiles (simulated by propane) were injected through a single injector at the base of the air-fluidized bed. Time-resolved oxygen concentrations were measured in-situ by a Zirconia oxygen sensor for resolution into the radial dispersion components. The radial dispersion coefficient for volatiles combustion rate was deduced by fitting plume model predictions to measurements of the heat release rate within the bed. The turbulent radial dispersion was compared to the radial dispersion for combustion. Within experimental error, the turbulent radial dispersion coefficient could be used in the plume model to predict the in-bed combustion rate of volatiles only for the 1.55mm sand particles. For the 0.78 and 0.55mm sand particles, the turbulent dispersion coefficient was substantially lower than the combustion dispersion coefficient. This was attributed to the occurrence of clouded bubbles in the beds of smaller sand particles, to which the plume model cannot be applied. For small particle sizes, a different volatiles combustion model needs to be developed.

Stubington, J.F.; Clough, S.J. [Univ. of New South Wales, Sydney, New South Wales (Australia)

1997-12-31

282

Fluidized bed gasification of select granular biomaterials.  

PubMed

Biomaterials can be converted into solid, liquid and gaseous fuels through thermochemical or biochemical conversion processes. Thermochemical conversion of granular biomaterials is difficult because of its physical nature and one of the suitable processes is fluidized bed gasification. In this study, coir pith, rice husk and saw dust were selected and synthetic gas was generated using a fluidized bed gasifier. Gas compositions of product gas were analyzed and the percentage of carbon monoxide and carbon dioxide was in the range of 8.24-19.55 and 10.21-17.14, respectively. The effect of equivalence ratio (0.3, 0.4 and 0.5) and reaction time (at 10 min interval) on gas constituents was studied. The gas yield for coir pith, rice husk and sawdust were found to be in the range of 1.98-3.24, 1.79-2.81 and 2.18-3.70 Nm3 kg(-1), respectively. Models were developed to study the influence of biomaterial properties and operating conditions on molar concentration of gas constituents and energy output. PMID:20817445

Subramanian, P; Sampathrajan, A; Venkatachalam, P

2011-01-01

283

Granular behavior in gas-fluidized beds  

NASA Astrophysics Data System (ADS)

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

Ojha, Rajesh Prasad

284

Electrically enhanced fluidized bed heat exchanger  

SciTech Connect

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

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

1994-05-01

285

User converts gas boiler to fluidized bed to save $1. 5M  

Microsoft Academic Search

Retrofitting a fluidized bed combustion (FBC) system may allow Clayton Foods Inc. to reduce its annual fuel bill by $1.5 million when the system comes on line in 1986. The system will burn low-grade, high-sulfur coal instead of natural gas, and should pay back the $4.1 million investment in under five years. The dual bed design separates the chemical processes

1985-01-01

286

Fluidized bed combustion of high ash anthracite: Analysis of combustion efficiency and particle size distribution  

Microsoft Academic Search

Fluidized bed combustion of high ash anthracite (HAA) was experimentally studied. The combustor consists of 0.25 m ID bed,\\u000a and auxiliary equipments for coal feeding, ash removal, lemperature control, etc. Experimental results elucidate main cause\\u000a of fuel loss to be elutriation of fines (i.e., flyash) containing unburned carbon. However, detailed balances of particle\\u000a size distribution show majority of carbon in

Yongwon Jung

1988-01-01

287

Evaluation of freeboard performance in a fluidized bed combustor  

SciTech Connect

Under a cooperative agreement between the US Agency for International Development (USAID) and the Government of India (GOI), a joint research project in fluidized bed combustion (FBC) was carried out by the Bharat Heavy Electricals Ltd. (BHEL), India, and the Oak Ridge National Laboratory (ORNL). The project was aimed at obtaining basic engineering data on the combustion of high-ash Indian coals (up to 45% ash), and coal washery rejects (up to 70% ash). Quantitative measurements of overall combustion efficiency, in-bed and freeboard combustion, in-bed heat transfer coefficient, freeboard heat transfer coefficient, flue gas composition and temperature profiles in the bed and freeboard were of particular interest. A 1 m {times} 1 m cross section, 11.0-m high, refractory-lined FBC was erected at BHEL, Trichy. The combustor was designed as a hot water generator with a capacity of 90 t/h at 10 kg/cm{sup 2} and 179{degree}C. Tests were conducted on a sub-bituminous Indian coal ({approximately}38% ash) and a coal washery reject (65% ash), with and without flyash reinjection. Both underbed and overbed fuel feeding modes were tested in the facility. Three series of long-duration tests typically lasting 40 to 50 h were conducted in the facility for a total of 600 h after about 300 h of shakedown testing. Operational problems associated with underbed/overbed feeding, flyash reinjection and ash removal were identified. 26 refs., 44 figs., 1 tab.

Krishnan, R.P.; Anthony, J.; Chandrasekhar, S.; Murthy, A.V.; Rajaram, S.; Rao, A.V.J.; Rajavel, M.; Srinivasan, S. (Oak Ridge National Lab., TN (USA); Bharat Heavy Electricals Ltd., Trichy (India))

1989-12-01

288

Impact of the Circulating Fluidized Bed Riser on the Performance of a Loopseal Nonmechanical Valve  

SciTech Connect

Most advanced coal-fuel power systems require the transfer and control of solids between two or more vessels. In many instances, the key to a successful process operation is how well the solids transfer and control system has been designed. This is particularly true in a transport gasifier and circulating fluidized bed (CFB) combustors, which are dependent upon the rapid and reliable circulation of solids to maintain a constant solids concentration in the CFB. Proper design and operation of solids returning systems are essential to the performance and operation of CFB combustion systems. An experimental investigation was conducted at the National Energy Technology Laboratory (NETL) of the U.S. Department of Energy (DOE) to study the flow and control of a light material (cork), which has a particle density of 189 kg/m3 and a mean diameter of 812 ím, through a nonmechanical valve, or loopseal, in a 0.3 m diameter CFB cold model. Fluidizing this material in ambient air approximates the same gas:solids density ratio as coal and coal char in a pressurized gasifier. The loopseal is composed of the lower section of the standpipe, an upward-flowing fluidized-bed section, and a downwardly angled overflow tube which is connected to the desired return point at the bottom of the riser. In the nonmechanical valve, both the standpipe and the fluidized-bed up-flow section of the loopseal were aerated and fluidized with air, respectively. The objective of this study was to investigate the effects of standpipe aeration, loopseal aeration, solids inventory, and superficial gas velocity through the riser on the flow rate of circulating solids. A correlation that predicts the solids flow rate as a function of these variables was developed. Comparison of the correlation with the experimental data is discussed. Pressure drop across the fluidized-bed up-flow section of the loopseal was found to increase slightly with the solid flow rates.

Monazam, E.R.; Shadle, L.J.; Mei, J.S.

2007-03-14

289

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...

290

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...

291

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

292

Solids feed nozzle for fluidized bed  

DOEpatents

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

Zielinski, Edward A. (Harwinton, CT)

1982-01-01

293

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

294

Behavior of fluidized beds similar to equilibrium states  

E-print Network

Systematic simulations are carried out based on the model of fluidized beds proposed by the present authors [K.Ichiki and H.Hayakawa, Phys. Rev. E vol.52, 658 (1995)]. From our simulation, we confirm that fluidization is a continuous transition. We also confirm the existence of two types of fluidized phases, the channeling phase and the bubbling phase. We find the close relations between the averaged behaviors in fluidized beds and quasi equilibrium states in dense liquids. In fluidized beds, (i) the flow rate plays the role of the effective temperature, and (ii) the existence of a kind of the fluctuation-dissipation relation is suggested.

Kengo Ichiki; Hisao Hayakawa

1997-04-25

295

Effects of high temperature and combustion on fluidized material attrition in a fluidized bed  

Microsoft Academic Search

This study investigated the effects of high temperature and combustion conditions on the attrition of fluidized material in\\u000a a fluidized bed. Silica sand was fluidized in air at an atmospheric pressure between 873 K and 1,073 K. The operating parameters\\u000a evaluated in investigating the attrition rate of fluidized material included particle size, temperature and both combustion\\u000a and non-combustion conditions. Experimental

Chiou-Liang Lin; Ming-Yen Wey

2003-01-01

296

21 CFR 890.5160 - Air-fluidized bed.  

Code of Federal Regulations, 2010 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...

2010-04-01

297

Guidelines for using refractories in circulating fluidized-bed combustors  

SciTech Connect

This manual provides preliminary guidelines for refractory practice in circulating fluidized-bed combustors (CFBCs). The guidelines are based on initial refractory experience in operating CFBCs and on experience with related processes, mainly in the oil refining industry. 24 refs.

Crowley, M.S.; Bakker, W.T. (ed.); Pred, R.J.

1991-04-01

298

JPL in-house fluidized-bed reactor research  

NASA Technical Reports Server (NTRS)

Fluidized bed reactor research techniques for fabrication of quartz linears was reviewed. Silane pyrolysis was employed in this fabrication study. Metallic contaminant levels in the silicon particles were below levels detectable by emission spectroscopy.

Rohatgi, N. K.

1984-01-01

299

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

300

Experiences in regenerating sulfated limestone from fluidized-bed combustors  

Microsoft Academic Search

The experiences at Argonne National Laboratory in developing a process for regenerating the partially sulfated limestone product from a fluidized-bed combustion process are described. Studies of candidate processes and the further development of the reductive-decomposition process wherein CaSOâ is converted to CaO in a fluidized bed at 1100°C are discussed. Reductive decomposition reaction rates are rapid--less than 10 minutes is

G. J. Vogel; J. Montagna; W. Swift; A. A. Jonke

1978-01-01

301

Combustion of Cattle Manure in a Fluidized Bed Combustor  

E-print Network

Station, Texas College Station, Texas ABSTRACT Manure from cattle feedlots is a renewable energy source which has the potential of supplementing the existing fossil fuels, but the heat content of manure is rather low. Since, the fluidized bed... Station, Texas College Station, Texas ABSTRACT Manure from cattle feedlots is a renewable energy source which has the potential of supplementing the existing fossil fuels, but the heat content of manure is rather low. Since, the fluidized bed...

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

302

Proceedings of the sixth international conference on fluidized bed combustion. Volume II. Technical sessions  

SciTech Connect

The Sixth International Conference on Fluidized Bed Combustion was held April 9-11, 1980, at the Atlanta Hilton, Atlanta, Georgia. It was sponsored by the US Department of Energy, the Electric Power Research Institute, the US Environmental Protection Agency, and the Tennessee Valley Authority. The papers covered recent developments in atmospheric and pressurized fluidized-bed combustion, especially the design, operation and control of pilot and demonstration plants. The cleanup of combustion products and the erosion, corrosion and fouling of gas turbines was emphasized also. Fifty-five papers from Volume 2 of the proceedings have been entered individually into EDB and ERA; five papers had been entered previously from other sources. (LTN)

none,

1980-08-01

303

Parametric performance studies on fluidized-bed heat exchangers. Quarterly technical progress report, 28 July-30 September 1981  

SciTech Connect

Analyses and experiments will be performed in this program to investigate the performance of single- and multi-stage shallow fluidized beds for possible application to the recovery of heat from sources such as waste heat, and coal combustion or coal gasification. This work is an extension of work done previously under Contracts EC-77-C-03-1433 and DE-AC03-79ET11348. In this program, tests will be conducted to (1) investigate the effects of fouling due to liquid condensate in the gas stream on fluidized bed heat exchanger performance, (2) investigate the performance of fluidized beds which are staged using baffle plates, and (3) investigate the effects of different heat exchanger surface geometries. During the quarter ending 30 September 1981, work progressed in selecting the conditions for that portion of the program involving fouling by a liquid condensate. Modifications were made to the Fluidized Bed Heat Exchanger Facility for the fouling experiments and plans were developed for preliminary tests in those investigations.

Not Available

1981-10-29

304

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

SciTech Connect

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

Fletcher, J.V.

1992-01-01

305

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...

306

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 ...

307

Monitoring fluidized bed drying of pharmaceutical granules.  

PubMed

Placebo granules consisting of lactose monohydrate, corn starch, and polyvinylpyrrolidone were prepared using de-ionized water in a high-shear mixer and dried in a conical fluidized bed dryer at various superficial gas velocities. Acoustic, vibration, and pressure data obtained over the course of drying was analyzed using various statistical, frequency, fractal, and chaos techniques. Traditional monitoring methods were also used for reference. Analysis of the vibration data showed that the acceleration levels decreased during drying and reached a plateau once the granules had reached a final moisture content of 1–2 wt.%; this plateau did not differ significantly between superficial gas velocities, indicating a potential criterion to support drying endpoint identification. Acoustic emissions could not reliably identify the drying endpoint. However, high kurtosis values of acoustic emissions measured in the filtered air exhaust corresponded to high entrainment rates. This could be used for process control to adjust the fluidization gas velocity to allow drying to continue rapidly while minimizing entrainment and possible product losses. PMID:21061102

Briens, Lauren; Bojarra, Megan

2010-12-01

308

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

309

FLUIDIZED BED STEAM REFORMING ENABLING ORGANIC HIGH LEVEL WASTE DISPOSAL  

SciTech Connect

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

Williams, M

2008-05-09

310

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

311

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

...2014-01-01 false Use of fluidized bed combustion not feasible-general...Exemptions § 503.10 Use of fluidized bed combustion not feasible—general...basis that use of a method of fluidized bed combustion of an alternate...

2014-01-01

312

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

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Use of fluidized bed combustion not feasible-general...Exemptions § 503.10 Use of fluidized bed combustion not feasible—general...basis that use of a method of fluidized bed combustion of an alternate...

2012-01-01

313

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

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Use of fluidized bed combustion not feasible-general...Exemptions § 503.10 Use of fluidized bed combustion not feasible—general...basis that use of a method of fluidized bed combustion of an alternate...

2011-01-01

314

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

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Use of fluidized bed combustion not feasible-general...Exemptions § 503.10 Use of fluidized bed combustion not feasible—general...basis that use of a method of fluidized bed combustion of an alternate...

2010-01-01

315

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

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Use of fluidized bed combustion not feasible-general...Exemptions § 503.10 Use of fluidized bed combustion not feasible—general...basis that use of a method of fluidized bed combustion of an alternate...

2013-01-01

316

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

317

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

318

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

319

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

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

320

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

321

Methods of forming a fluidized bed of circulating particles  

DOEpatents

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

Marshall, Douglas W. (Blackfoot, ID)

2011-05-24

322

Utilizing the fluidized bed to initiate water treatment on site  

SciTech Connect

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

Ahmadvand, H. [Arco Pipeline Co., Colvis, NM (United States); Germann, G. [Sinclair Pipeline Co., Carrollton, MO (United States); Gandee, J.P. [Blasland, Bouck and Lee, Westerville, OH (United States); Buehler, V.T. [Envirex, Inc., Waukesha, WI (United States)

1995-12-31

323

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

324

Incineration of paper sludge in a prototype vortexing fluidized bed combustor.  

PubMed

All experiments were carried out in a prototype vortexing fluidized bed combustor (VFBC). The dimension of the combustion chamber is 0.7 x 1.4 x 2 m, and the freeboard section is 1 m i.d. and 4 m in height. Paper sludge was used as the feeding material. Two types of coal particles were employed as the supplementary fuel. In order to understand the characteristics of the VFBC system for paper sludge incineration, the effect of various operating parameters, such as the primary airflow, excess air ratio, and secondary airflow rates, on temperature distribution, ash elutriation, combustion efficiency, and pollutant emissions were investigated. PMID:11321911

Chyang, C S; Liu, C Y; Chang, Y D

2001-04-01

325

Conversion of solid carbonaceous fuels in a fluidized bed fuel cell  

SciTech Connect

A fluidized bed direct carbon fuel cell was employed to achieve direct conversion of solid fuels into electricity. Power was generated from pulverized Lower Kittanning (bituminous) coal, synthetic carbon, and biomass in a single process step. Current-voltage characteristics exhibited typical fuel cell behavior. Fluidization in flowing CO{sub 2} overcomes the difficulty of attaining solid fuel-to-anode contact and generates CO in situ via the Boudouard reaction. A mechanistic reaction pathway is proposed for anodic oxidation of the solid fuel. Conversion was verified by gas analysis of oxidation products in the flue stream and by oxygen mass balance.

Lee, A.C.; Li, S.; Mitchell, R.E.; Guer, T.M. [Stanford University, Stanford, CA (United States). Dept. of Mechanical Engineering

2008-07-01

326

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

327

Development of novel two-interconnected fluidized bed system  

Microsoft Academic Search

Two-interconnected fluidized bed systems are widely used in various processes such as Fisher-Tropsch, hot gas desulfurization,\\u000a CO2 capture-regeneration with dry sorbent, chemical-looping combustion, sorption-enhanced steam methane reforming, chemical-looping\\u000a hydrogen generation system, and so on. However, conventional two-interconnected fluidized bed systems are very complex, large,\\u000a and difficult to operate because most of these systems require a riser and\\/or pneumatic transport line

Ho-Jung Ryu; Young-Cheol Park; Sung-Ho Jo; Moon-Hee Park

2008-01-01

328

Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes  

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 and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to a water drum and in the path of the air and the gaseous products of combustion exiting from the bed. Another portion of the tubes pass through the bed and extend at an angle to the upper surface of the bed.

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

1980-01-01

329

Regeneration of lime from sulfates for fluidized-bed combustion  

DOEpatents

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

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

1980-01-01

330

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

331

Pyrolytic conversion of carbonaceous solids to fuel gas in quartz sand fluidized beds  

Microsoft Academic Search

Particulate carbonaceous solids are pyrolytically converted to fuel gas in a fluidized bed containing quartz sand as the primary inert heat-transfer medium. In addition to the quartz sand, the fluidized bed contains an anti-agglomerating composition consisting of a carbonate or oxide of calcium, magnesium, or barium, or mixtures thereof. The formation of sand agglomerates (viz. clinkers) interfering with fluidized bed

L. T. Fan; W. P. Walawender

1984-01-01

332

Assessment of ettringite from hydrated FBC residues as a sorbent for fluidized bed desulphurization  

Microsoft Academic Search

The performance of synthetic ettringite as a sorbent in fluidized bed desulphurization has been assessed and compared with that of a commercial limestone. Experiments have been carried out in a bench scale fluidized bed reactor under simulated desulphurizing (steadily oxidizing) combustion conditions. Sorbent performance has been characterized in terms of desulphurization rate, maximum sulphur uptake and attrition propensity. Fluidized bed

Fabio Montagnaro; Piero Salatino; Fabrizio Scala; Graziella Bernardo; Gian Lorenzo Valenti

2003-01-01

333

Fate of solids fed pneumatically through a jet into a fluidized bed  

Microsoft Academic Search

Solid tracer particles were fed pneumatically through a jet into a fluidized bed to simulate the feeding of solids via a pneumatic transport line into a fluidized-bed reactor operating in the slugging-bed mode. The fluidized bed was defluidized instantaneously at different times after the initiation of the tracer particle injection. The bed was then sampled layer by layer to provide

Ifiyenia Kececioglu; D. L. Keairns; W. C. Yang

1984-01-01

334

Electrochemical struvite precipitation from digestate with a fluidized bed cathode microbial  

E-print Network

Electrochemical struvite precipitation from digestate with a fluidized bed cathode microbial phosphorus recov- ery Bio-electrochemical fluidized bed reactor Struvite a b s t r a c t Microbial-chamber MEC was designed with a fluidized bed to produce suspended particles and inhibit scale formation

335

Emergent Behavior in a Low-Order Fluidized-Bed Bubble Model  

E-print Network

Emergent Behavior in a Low-Order Fluidized-Bed Bubble Model John S. Halow National Energy of this type of model to describe the dynamics of voids in bubbling fluidized beds. The model considers vertical interactions between neighboring bubbles in fluidized beds. Emergent collective behavior is shown

Tennessee, University of

336

Alumina atomic layer deposition nanocoatings on primary diamond particles using a fluidized bed reactor  

E-print Network

Alumina atomic layer deposition nanocoatings on primary diamond particles using a fluidized bed particles in a scalable fluidized bed reactor. The studies of fluidization at reduced pressure show; Atomic layer deposition (ALD); Fluidized bed reactor 1. Introduction Due to its extreme hardness, diamond

George, Steven M.

337

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

E-print Network

NUMERICAL AND EXPERIMENTAL ANALYSIS OF A FLUIDIZED BED FOR IFE TARGET LAYERING Kurt J. Boehm1 , A surface (in particular the thin high-Z coating). This effort includes developing a numerical fluidized bed targets (~4.0 mm) compared to the size of the prototypic fluidized bed container (~26 mm in diameter

Raffray, A. René

338

Adaptive higher order numerical simulation of heat and mass transfer in fluidized beds  

E-print Network

Adaptive higher order numerical simulation of heat and mass transfer in fluidized beds Ch. Nagaiah1 adaptive numerical results of heat and mass transfer in fluidized beds using higher order time stepping for the solution of concentration and temperature distributions inside fluidized beds (FB) with liquid spray

Magdeburg, Universität

339

Analysis of statistical quantities in simulation of fluidized beds Kengo Ichiki* and Hisao Hayakawa  

E-print Network

Analysis of statistical quantities in simulation of fluidized beds Kengo Ichiki* and Hisao Hayakawa on the model of fluidized beds proposed by the present authors Phys. Rev. E 52, 658 1995 . In our simulation of its variety of dynamical behaviors 4,5 . Fluidized beds have been widely used in chemical indus- tries

Ichiki, Kengo

340

Experimental analysis and visualization of spatiotemporal patterns in spouted fluidized beds  

E-print Network

Experimental analysis and visualization of spatiotemporal patterns in spouted fluidized beds data of the spouting regime in a two-dimensional fluidized bed is presented. The aspect ratio revealed that the hy- drodynamics of fluidized beds exhibit many features as- sociated with low

341

Control of crystallization and caking of skim milk powder in fluidized beds: A preliminary study  

E-print Network

Note Control of crystallization and caking of skim milk powder in fluidized beds: A preliminary January 2010 Published online 18 March 2010 Abstract ­ A stirred fluidized bed has been used with the aim was crystallized in a stirred fluidized bed, then a sorption box was used to characterize the stability

Paris-Sud XI, Université de

342

Performance Model of the Fluidized Bed Copper Oxide Process for SO2/NOx Control  

E-print Network

93- 79.01 1 Performance Model of the Fluidized Bed Copper Oxide Process for SO2/NOx Control H H.C. Frey #12;93- 79.01 2 INTRODUCTION The fluidized bed copper oxide process is an advanced design issues, including overall sulfur removal efficiency, fluidized bed absorber height, sorbent copper

Frey, H. Christopher

343

Characterizing the Hydrodynamics of Bubbling Fluidized Beds with Multivariate Pressure Measurements  

E-print Network

Characterizing the Hydrodynamics of Bubbling Fluidized Beds with Multivariate Pressure Measurements Knoxville TN 37996-2210 Abstract Quantitative characterization of fluidized-bed hydrodynamics is important for process monitoring and validation of dynamic models. Using a two-dimensional fluidized bed of Geldart

Tennessee, University of

344

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

345

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

346

CFD simulations of particle mixing in a binary fluidized bed  

Microsoft Academic Search

It has long been known that fluidization of dissimilar materials can result in either a well-mixed bed or a segregated bed. In a fluidized bed, particle mixing and segregation phenomena are dominated by bubble activity. Depending on operating conditions, lighter or smaller particles (“flotsam”) tend to rise to the bed, and larger, heavier particles (“jetsam”) tend to sink to the

Scott Cooper; Charles J. Coronella

2005-01-01

347

Drying of granular materials in circulating fluidized beds  

Microsoft Academic Search

It is attempted in the present investigation to dry solid materials in the riser of circulating fluidized bed covering a wide range of operating parameters. The effects of initial moisture content, temperature and flow rate of the heating medium, and solid circulation rate on rate of drying, have been critically examined. It has been observed that the solids material used

N. Balasubramanian; C. Srinivasakannan

2007-01-01

348

Design and Application of Novel Horizontal Circulating Fluidized Bed Boiler  

Microsoft Academic Search

The vertical circulating fluidized bed (CFB) boiler has been found wide application in power generation and tends to be enlarged in capacity. Because CFB is one of environment friendly and high efficiency combustion technologies, the CFB boiler has also been expected to be used in the industrial area, such as textile mill, region heating, brewery, seed drying and so on.

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

2010-01-01

349

Fluidized bed riser as a dry particle separation system  

Microsoft Academic Search

An exploratory study was undertaken to demonstrate the potential for using a fluidized bed riser system for the dry separation of fine particles. The experimental system consisted of a constant-diameter riser, two different operational heights, optional internal rings and one specific test mixture. Good separation efficiencies were obtained with a modest mass flux through the system. Further research is required

E. K. Johnson; J. L. Regester; B. S. J. Kang

2005-01-01

350

LEVEL 2 CHEMICAL ANALYSIS OF FLUIDIZED-BED COMBUSTOR SAMPLES  

EPA Science Inventory

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

351

Drying Suspensions in a Pulsed Fluidized Bed of Inert Particles  

Microsoft Academic Search

The drying of carbohydrate suspensions on polypropylene particles in a pulsed fluidized bed was studied by means of a 2 experimental design, to determine the effect of the air flow and temperature, suspension flow rate, and free section and rotating speed of the rotary plate on the Nusselt number, the moisture content of the product, and the percentage of solids

Alejandro Reyes; Nicolás Herrera; Ricardo Vega

2007-01-01

352

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

353

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

354

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

Microsoft Academic Search

Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of high sodium aqueous radioactive wastes. The addition of clay and a catalyst as co-reactants converts high sodium aqueous low activity wastes (LAW) such as those existing at the Hanford and Idaho DOE sites to a granular ''mineralized'' waste form that

C. M. Jantzen; T. H. Lorier; J. C. Marra; J. M. Pareizs

2006-01-01

355

Application of gamma-ray tomography to gas fluidized beds  

Microsoft Academic Search

Noninvasive gamma ray tomography is a powerful technique for accurate measurement of time-averaged density distributions in single-phase and multiphase systems and the elucidation of internal structures. This paper discusses its use to assist the understanding of the fluid mechanics of fluidized beds.

N. MacCuaig; J. P. K. Seville; W. B. Gilboy; R. Clift

1985-01-01

356

FLUIDIZED BED REACTOR STUDY. Reactor Design and Feasibility Study  

Microsoft Academic Search

A feasibility study of a fluidized bed reactor system was undertaken. ; Initial studies were conducted on a fast, sodium cooled system, a gas cooled ; system, and organic and water moderated thermal systems. The organic moderated ; and light water moderated systems showed promise. The light water system was ; chosen for a detailed study to enable comparison with

C. L. Teeter; T. Ciarlariello; B. L. Hoffman; D. H. Jorgensen; F. D. Judge; L. J. King; D. A. McCune; N. R. Scheve; H. E. Zellnik

1957-01-01

357

Prediction of wear in a fluidized bed. Technical note  

SciTech Connect

The formulation of a procedure to model wear of surfaces exposed to a fluidized bed is discussed. A stochastic methodology adapting kinetic theory of gases to granular flows is used to derive an impact wear model. It uses a single-particle wear model to account for impact wear from all possible particle collisions. An adaptation of an empirical 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 solution of the wear expressions, are found using a computer code to model the fluidized bed hydrodynamics. Additional parameters describing the contact between fluidized particles and the wearing surface are determined with an optimization procedure based on wear measurements. The modeling procedure was applied to various bubbling and turbulent fluidized beds with single-tube and tube bundle configurations. Quantitative agreement between measured and predicted wear rates was exhibited with some exceptions for local wear predictions. Improvements in both the analytic wear expression and the computer code used to model bed hydrodynamics are needed to accurately predict local wear, thus providing true predictive capability.

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

1991-09-01

358

Heavy metal removal from wastewater in fluidized bed reactor  

Microsoft Academic Search

An innovative process for removing heavy metals including Cu, Ni and Zn from industrial wastewater has been developed. The new technology was based on inducing the nucleated precipitation of heavy metals on the sand surface in a fluidized bed reactor. The results showed that pH had a great effect on heavy metal removal efficiency and the optimum pH was about

Ping Zhou; Ju-Chang Huang; Alfred W. F Li; Shirly Wei

1999-01-01

359

Development of “AI-VISION” for fluidized-bed incinerator  

Microsoft Academic Search

The paper presents “AI-VISION” which is an intelligent combustion control equipment for a fluidized-bed incinerator (FBI). Since thermal plants are MIMO systems, it is important to grasp the characteristic of the plant by sensors for precise combustion control. Furthermore, in a refuse incineration plant (RIP), the fuel property is unstable and minimization of exhaust emission is required. Thus, optimization from

Yuichi MIYAMOTO; Kimiyoshi NISHINO; Tsuneyoshi SAWAI; Eiichiro NAMBU

1996-01-01

360

Dynamics of gas-particle flow in circulating fluidized beds  

Microsoft Academic Search

The flow of gas—particle mixtures in a circulating fluidized bed has been studied, probing the flow behavior under both stable and unstable operating conditions. A novel feature of our work is the use of electrical capacitance tomography to image particle distribution over the cross-section at one elevation in the standpipe. In addition, we have also obtained data on pressure profile

A. Srivastava; K. Agrawal; S. Sundaresan; S. B. Reddy Karri; T. M. Knowlton

1998-01-01

361

Experimental study and modeling of fluidized bed coating and agglomeration  

Microsoft Academic Search

This work deals with the fluidized bed coating and agglomeration of solid particles. The effect of particle size on coating criteria was investigated using sand particles as the coating support and aqueous solutions containing NaCl as coating liquid. The results showed that both growth rate and efficiency increase with decreasing the particle size. The growth was mainly governed by layering

K. Saleh; D. Steinmetz; M. Hemati

2003-01-01

362

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

363

Computation of flow patterns in circulating fluidized beds  

Microsoft Academic Search

This paper reports on flow regimes of dense-phase vertical pneumatic transport of solids, referred to in the literature as circulating fluidized beds, computed using a generalization of the Navier-Stokes equations for two fluids. In the less dense regime corresponding to volume fractions of solids of about 1%, the flow consists of centrally upward moving solids and downward moving clusters. The

Yuan P. Tsuo; D. Gidaspow

1990-01-01

364

JPL in-house fluidized bed reactor research  

NASA Technical Reports Server (NTRS)

The progress in the in-house program on the silane fluidized-bed system is reported. A seed-particle cleaning procedure was developed to obtain material purity near the level required to produce a semiconductor-grade product. The liner-seal design was consistently proven to withstand heating/cooling cycles in all of the experimental runs.

Rohatgi, N. K.

1985-01-01

365

JPL in-house fluidized-bed reactor research  

NASA Technical Reports Server (NTRS)

Data is given on metallic impurities in fluidized bed reactors (FBR). Various wall materials for FBR's are characterized. Reaction paths for FBR's and conditions for the incorporation of homogenous fines onto seed particles are discussed. Scavenging experiment data and jet mill grinding data are given.

Hsu, G. C.

1984-01-01

366

Direct indication of particle size in fluidized beds  

NASA Technical Reports Server (NTRS)

Differential pressure measurements indicate particle size and particle size distribution in fluidized beds. The technique is based on the relationship between bed particle size and the intensity and frequency of fluctuations. By measuring the fluctuations, an estimate of average particle size of the fluid-bed material can be made.

Knudsen, I. E.; Olsen, W. F.

1969-01-01

367

TREATMENT OF MUNICIPAL WASTEWATERS BY THE FLUIDIZED BED BIOREACTOR PROCESS  

EPA Science Inventory

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

368

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

369

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

SciTech Connect

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

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

1980-06-01

370

Hydrodynamics and interfacial gas-liquid mass transfer of gas-liquid-solid fluidized beds  

SciTech Connect

Hydrodynamic characteristics of a cocurrent, gas-liquid-solid fluidized bed is studied to simulate the resid hydrotreating reaction conditions using an aqueous surfactant solution. Reaction conditions for hydrotreating of residual oils and coal liquefaction, which uses cylindrical hydrotreating catalysts under conditions of high gas holdup, are simulated using an aqueous t-pentanol (0.5 wt%) solution as the liquid phase. A mathematical model is developed to described the minimum fluidization velocity behavior. Bed voidage, gas holdup and terminal velocity of the particles are analyzed and correlated empirically to investigate the effect of particle shape and liquid surface tension. Systematic effects of particle properties on bubble wake structure as well as bubble rise characteristics for a single rising bubble in a liquid-solid fluidized bed are studied visually. In order to determine the solids holdup in near wake behind a single bubble, an image processing technique is employed. The bubble rise velocity, the volume ratio of primary wake to bubble, the volume ratio of liquid wake to bubble, and the wake solid holdup are strongly dependent on the particle terminal velocity and the bed expansion. A spectrophotometric technique is developed for the measurement of the instantaneous mass transfer coefficient and the interfacial areas of a bubble as well as the local concentration distribution around the bubble-wake. An ozone and starch-potassium iodide reaction is employed to visualize the gas-liquid mass transfer to a single bubble in liquids and liquid-solid fluidized beds. Axial variations of the concentration, bubble volume and the mass transfer rate are studied. The mass transfer coefficient is found to be dependent on bubble size and bed expansion.

Song, Gyung-Ho.

1989-01-01

371

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

372

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

373

Numerical Analysis of using a Fluidized Bed as a Prototypic Mass Production Device for IFE Target Layering  

E-print Network

Numerical Analysis of using a Fluidized Bed as a Prototypic Mass Production Device for IFE Target, USA Abstract--A fluidized bed has been identified as a very promising method for mass production for the fluidized bed model, as it affects the unbalance of the individual spheres. Keywords- Fluidized bed, IFE

Raffray, A. René

374

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

PubMed

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

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

2011-01-01

375

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

376

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

377

Sorbent performance in fluidized-bed combustors: The effect of calcination on the sulfation rate and calcium utilization  

NASA Astrophysics Data System (ADS)

This investigation was conducted to determine if greater amounts of SOsb2 can be removed by naturally occurring sorbents from coal-fired, atmospheric, fluidized-bed combustors if a greater understanding of the calcination process during simultaneous calcination and sulfation is ascertained. A bench-scale, fluidized-bed reactor, ca. 68 insp3 (1,114 cmsp3) of total volume, 1.5 inI.D., utilizing 100 mesh U.S. Standard Sieve stainless steel screens for a frit, was successfully operated and found to be capable of producing the necessary, repeatable data for addressing the hypothesis. Electronic mass flow meters were used to deliver a synthetic gas mixture consisting of Nsb2,\\ Osb2,\\ COsb2, and SOsb2. On-line gas analyzers were used to measure the real-time effluent concentrations of the latter three species. Gas compositions usually consisted of 4 vol% Osb2; 2,000 vppm SOsb2; 0-40 vol% COsb2; and the balance Nsb2. Three limestones with particles sizes ranging from 150 to 1,000 mum were used along with sized quartz for bed material. All experiments were performed at atmospheric pressure with temperatures generally ranging from 850 to 900sp°C. Calcination and sulfation occur simultaneously with respect to time and both the sulfation rate and calcium utilization generally increase with increasing calcination rates. COsb2-induced sintering decreases the calcine surface area while simultaneously increasing the mean diameter pore size; the significant reduction in developed surface area negates any perceived benefit of larger mean diameter pores for increased sorbent performance. Additionally, the use of elevated concentrations of COsb2 in an attempt to minimize the development of an impermeable CaSOsb4 rim via the slow release of COsb2 through the porous solid is generally not a viable method for increasing the sorbent performance (sulfation rate and calcium utilization) since intra-particle, thermally-induced fractures provide access paths for CaO located towards the center of the particle-negating the benefits of larger pores and the slow "percolation" of COsb2 through the porous matrix. The calcination process was successfully modeled wherein intra-particle partial pressures of COsb2 and extents of calcination are quantified.

Romans, David Earl

378

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

SciTech Connect

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

Hui Wang; Xiumin Jiang; Jianguo Liu; Weigang Lin [Shanghai Jiao Tong University, Shanghai (China). School of Mechanical Engineering

2007-08-15

379

Transfer function matrix model of the bubbling fluidized bed boiler  

NASA Astrophysics Data System (ADS)

The paper presents proposal of a model of the fluidized bed boiler adapted for use in model-based controllers e.g. predictive, adaptive or internal model control (IMC). The model has been derived in the form of transfer function matrix which allows its direct implementation in the controller structure. Formulated model takes into consideration the principal cross-coupling between process variables which enables the opportunity to search for feasibility of decoupling control. The results of the identification of the dynamics of the 2 MW industrial bubbling fluidized bed boiler using the proposed model form was presented. According to the experimental data it was found that despite of introduced simplifications presented model allows the boiler behavior prediction.

Porzuczek, Jan

2011-12-01

380

Application of a fluidized bed combustor to the DARS process  

SciTech Connect

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

Scott-Young, R.E. [Australian Paper, Burnie, Tasmania (Australia). Pulp Mill and Services Unit

1995-12-31

381

Hysteresis and Contact forces in a Gas-fluidized Bed  

NASA Astrophysics Data System (ADS)

A gas-fluidized bed consists of an assembly of granular material fluidized by an upflow of gas. The "melting" of a static assembly of sand to the fluid state is hysteretic and proceeds through an intermediate state known as the "uniform fluid" which we have recently shown(Menon, N.; Durian, D.J. Particle motions in a gas-fluidized bed of sand. Phys. Rev. Lett., vol.79, 3407 (1997)) to be a weak, but motionless solid with enduring contacts between grains. We characterize the contact forces that stabilize this phase by measurements of the hysteresis in gas pressure vs gas velocity measurements and analyze them in terms of a yield stress for this soft solid. Since the chains of contact forces terminate at the boundaries of the bed, interesting boundary effects are anticipated. We probe finite-size effects in the magnitude of these forces obtained both by varying grain-size as well as aspect ratio of the bed.

Menon, Narayanan; Durian, Douglas

1998-03-01

382

Element associations in ash from waste combustion in fluidized bed  

SciTech Connect

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

Karlfeldt Fedje, K., E-mail: karinka@chalmers.s [Department of Chemical and Biological Engineering, Division of Environmental Inorganic Chemistry, Chalmers University of Technology, Kemivaegen 10, 412 96 Goeteborg (Sweden); Rauch, S. [Department of Civil and Environmental Engineering, Division of Water Environment Technology, Chalmers University of Technology, Sven Hultins Gata 8, 412 96 Goeteborg (Sweden); Cho, P.; Steenari, B.-M. [Department of Chemical and Biological Engineering, Division of Environmental Inorganic Chemistry, Chalmers University of Technology, Kemivaegen 10, 412 96 Goeteborg (Sweden)

2010-07-15

383

Fluidized bed combustor and removable windbox and tube assembly therefor  

DOEpatents

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

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

1981-01-01

384

Fluidized bed combustor and removable windbox and tube assembly therefor  

DOEpatents

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

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

1983-01-01

385

Fluidized-bed testing of Z-SORB III sorbent  

SciTech Connect

Phillips Petroleum Company (PPCo) successfully developed a fluidizable version of their proprietary Z-SORB sorbent. Z-SORB sorbent is a ZnO-based regenerable sorbent for removing hydrogen sulfide (H{sub 2}S) and carbonyl sulfide (COS). RTI conducted a life-cycle test on this sorbent in the high-temperature, high-pressure (HTHP) semi-batch fluidized-bed reactor. This test consisted of 50 cycles of sulfidation and regeneration to demonstrate the long-term chemical reactivity and mechanical strength of the Z-SORB sorbent. A simulated air-blown gasifier coal gas was used at 20 atm and 538 {degree}C (1,000{degree}F). The Z-SORB sorbent exhibited excellent sulfur removal capability; the prebreakthrough H{sub 2}S levels were below the detection limit of the analyzer (<10 ppmv). The sulfur capacity of the sorbent at breakthrough (500 ppM H{sub 2}S in reactor exit gas) was 20.2 g S/100 g sorbent in Cycle 1 and was 10 g S/100 g sorbent in Cycle 50. The sorbent loss from the reactor due to fines generation was small. While no significant change in particle size was observed, the bulk density increased by 8 percent over 51 cycles. The attrition resistance of the sorbent after the 51 cycles was slightly lower than the fresh material. The thermogravimetric analyzer (TGA) tests on fresh and reacted sorbents confirmed the sulfur capacity decline in the bench tests; however, the TGA data indicated no change in the H{sub 2}S absorption rate between the fresh and reacted sorbents. The regeneration of the sulfided sorbent was successfully carried out using 2 to 2.5 percent 0{sub 2} in N{sub 2} at a temperature of 649 to 704{degree}C (1,200 to 1,300{degree}F) with no evidence of sulfate formation. Overall, the sorbent exhibited good performance.

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

1994-08-01

386

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

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

2006-09-30

387

Spectral methods applied to fluidized bed combustors. Final report  

SciTech Connect

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

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

1996-08-01

388

Fluidized bed riser as a dry particle separation system  

SciTech Connect

An exploratory study was undertaken to demonstrate the potential for using a fluidized bed riser system for the dry separation of fine particles. The experimental system consisted of a constant-diameter riser, two different operational heights, optional internal rings and one specific test mixture. Good separation efficiencies were obtained with a modest mass flux through the system. Further research is required to optimize the separation process and bring the concept to commercial viability.

Johnson, E.K.; Regester, J.L.; Kang, B.S-J. [West Virginia University, Morgantown, WV (United States). Dept. of Aerospace & Mechanical Engineering

2005-08-01

389

Design and Application of Novel Horizontal Circulating Fluidized Bed Boiler  

Microsoft Academic Search

\\u000a The vertical circulating fluidized bed (CFB) boiler has been found wide application in power generation and tends to be enlarged\\u000a in capacity. Because CFB is one of environment friendly and high efficiency combustion technologies, the CFB boiler has also\\u000a been expected to be used in the industrial area, such as textile mill, region heating, brewery, seed drying and so on.

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

390

Biomass gasification in fluidized bed reactor with Co catalyst  

Microsoft Academic Search

The catalytic performance of Co\\/MgO catalysts (Co loading of 0–36wt%) for tar treatment in steam gasification of Radiata pine was investigated by means of the primary method using a fluidized bed reactor with Co\\/MgO catalyst as a fluidizing medium. Although the total amount of tar decreased with the presence of catalysts, water-insoluble components were found to increase while water-soluble components

Kazuhiko Tasaka; Takeshi Furusawa; Atsushi Tsutsumi

2007-01-01

391

Fluidized bed granulation: gas flow, particle motion and moisture distribution  

Microsoft Academic Search

In fluidized bed granulation the liquid is often distributed by means of a two-fluid-nozzle that is positioned inside the bed. Then the wetting process takes place in the jet that is formed by the atomizing air. A model has been derived for a free jet to calculate the particle and gas velocities, the void fraction and the cross-sectional area of

Rolf-Dieter Becher; Ernst-Ulrich Schlünder

1997-01-01

392

Attrition characteristics of alumina catalyst for fluidized bed incinerator  

Microsoft Academic Search

Attrition characteristics of alumina catalyst for catalytic incineration have been studied in a fluidized bed cold mode combustor\\u000a (F10 cm, 160 cm height). The particle size and density of alumina catalyst were 1.4-1.7 mm and 1.13 g\\/cm3. As operating variables,\\u000a excess gas velocity (U-Umf) and bed weight (Wb) were selected. The experimental results show that attrition rate of alumina catalyst

Yeong Seong Park; Han Soo Kim; Dowon Shun; Kwang Sup Song; Sung Kyu Kang

2000-01-01

393

Tar removal during the fluidized bed gasification of plastic waste  

Microsoft Academic Search

A recycled polyethylene was fed in a pilot plant bubbling fluidized bed gasifier, having an internal diameter of 0.381m and a maximum feeding capacity of 90kg\\/h. The experimental runs were carried out under various operating conditions: the bed temperature was kept at about 850°C, the equivalence ratio varied between 0.2 and 0.35, the amount of bed material was between 131

Umberto Arena; Lucio Zaccariello; Maria Laura Mastellone

2009-01-01

394

Air gasification of polypropylene plastic waste in fluidized bed gasifier  

Microsoft Academic Search

An experimental study on air gasification of polypropylene was conducted in a fluidized bed gasifier with an insider diameter (i.d.) of 100mm and a height of 4.2m. The effect of the equivalence ratio, bed height and fluidization velocity on various gasification results, including the product yield distribution, gas composition, gas heating value and gas yield were studied. The equivalence ratio

Rui Xiao; Baosheng Jin; Hongcang Zhou; Zhaoping Zhong; Mingyao Zhang

2007-01-01

395

HYDRODYNAMICS AND HEAT TRANSFER OF LIQUID FLUIDIZED BED SYSTEMS  

Microsoft Academic Search

After some genera] remarks about liquid\\/solid fluidization, various aspects of liquid fluidization hydrodynamics and heat transfer have been analyzed on a coherent basis. For each of these cases, the state-of-the-art has been reported, together with some indication of areas that deserve further attention. Major emphasis is placed on the hydrodynamic behavior of fluidized beds, heat transfer mechanisms from surface-to-bed and

M. JAMIALAHMADI; H. MÜLLER-STEINHAGEN

2000-01-01

396

Bed drain cover assembly for a fluidized bed  

DOEpatents

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

Comparato, Joseph R. (Bloomfield, CT); Jacobs, Martin (Hartford, CT)

1982-01-01

397

Anaerobic ammonium oxidation discovered in a denitrifying fluidized bed reactor  

Microsoft Academic Search

Until now, oxidation of ammonium has only been known to proceed under aerobic conditions. Recently, we observed that NH4+ was disappearing from a denitrifying fluidized bed reactor treating effluent from a methanogenic reactor. Both nitrate and ammonium consumption increased with concomitant gas production. A maximum ammonium removal rate of 0.4 kg N · m?3 · d?1 (1.2 mM\\/h) was observed.

A. Mulder; A. A. van de Graaf; L. A. Robertson; J. G. Kuenen

1995-01-01

398

Staged fluidized-bed combustion and filter system  

DOEpatents

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

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

1994-01-01

399

Investigation on Agropellet Combustion in the Fluidized Bed  

NASA Astrophysics Data System (ADS)

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

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

400

Tapered fluidized bed bioreactor for environmental control and fuel production  

SciTech Connect

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

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

1980-01-01

401

Numerical Study of Pyrolysis of Biomass in Fluidized Beds  

NASA Technical Reports Server (NTRS)

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

Bellan, Josette; Lathouwers, Danny

2003-01-01

402

Onset behavior of a liquid-fluidized bed  

NASA Astrophysics Data System (ADS)

We examine the onset of fluidization in experiments on liquid fluidized beds. Recent studies of gas fluidized beds have shown that the transition to fluidization is to a weak solid state with no particle motion(N. Menon and D. J. Durian, Phys. Rev. Lett. 79), 3407 (1997).. We find a similar behavior in liquid fluidized beds and explain this behavior in terms of a critical void fraction ?_c. If the initial void fraction ?i is less than ?_c, the bed undergoes transient fluidization, or rearrangement, as the flow rate F is increased above a critical flow rate F_trans. F_trans depends on ?i for ?_i?c the onset of fluidization is to the continuously fluidized state at F_cont(?_i) with no transient behavior.

Goldman, Daniel I.; Shattuck, M. D.; Swinney, Harry L.

2000-11-01

403

Onset behavior of a liquid-fluidized bed  

NASA Astrophysics Data System (ADS)

We investigate the onset of fluidization in liquid fluidized beds. Recent studies of gas fluidized beds have shown that initial onset of fluidization is to a weak solid state with no particle motion(N. Menon and D. J. Durian, Phys. Rev. Lett. 79)(18) 3407 (1997).. We find a similar behavior in liquid fluidized beds and explain this behavior in terms of a critical void fraction ?_c. If the initial void fraction ?I is less than ?_c, the bed undergoes transient fluidization, or rearrangement, as the flow rate F is increased above a critical flow rate F_trans. F_trans(?_I) depends on ?I for ?_I?c the onset of fluidization is to the continuously fluidized state at F_cont(?_I) with no transient behavior. Because of the dependence of fluidization on ?_I, flow rate cycling above and below onset can show hysteresis. However, after one cycle with F>F_cont, a critical state is produced for which the hysteresis disappears.

Shattuck, M. D.; Goldman, D.; Swinney, Harry L.

1998-11-01

404

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

EPA Science Inventory

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

405

Bench-scale testing of fluidized-bed sorbents -- ZT-4  

SciTech Connect

The objectives of this project are to identify and demonstrate methods for enhancing long-term chemical reactivity and attrition resistance of zinc oxide-based mixed metal-oxide sorbents for desulfurization of hot coal-derived gases in a high-temperature, high-pressure (HTHP) fluidized-bed reactor. Specific objectives of this study are the following: {sm_bullet} Investigating various manufacturing methods to produce fluidizable zinc ferrite and zinc titanate sorbents in a particle size range of 50 to 400 {mu}m; Characterizating and screening the formulations for chemical reactivity, attrition resistance, and structural properties; Testing selected formulations in an HTHP bench-scale fluidized-bed reactor to obtain an unbiased ranking of the promising sorbents; Investigating the effect of various process variables, such as temperature, nature of coal gas, gas velocity, and chemical composition of the sorbent, on the performance of the sorbent; Life-cycle testing of the superior zinc ferrite and zinc titanate formulations under HTHP conditions to determine their long-term chemical reactivity and mechanical strength; Addressing various reactor design issues; Generating a database on sorbent properties and performance (e.g., rates of reaction, attrition rate) to be used in the design and scaleup of future commercial hot-gas desulfurization systems; Transferring sorbent manufacturing technology to the private sector; Producing large batches (in tonnage quantities) of the sorbent to demonstrate commercial feasibility of the preparation method; and Coordinate testing of superior formulations in pilot plants with real and/or simulated coal gas.

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

1995-12-01

406

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

SciTech Connect

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

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

1993-04-01

407

Characterization of the hydrodynamic structure of a 3D acoustic fluidized bed.  

E-print Network

??Multiphase flow systems are used widely in various industrial processes. For example fluidized bed reactors are attractive because they provide uniform temperature distributions, low pressure… (more)

Escudero, David Roberto

2014-01-01

408

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

NASA Astrophysics Data System (ADS)

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

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

409

Degradation of polycyclic aromatic hydrocarbons by a marine fluidized-bed enrichment  

SciTech Connect

Aerobic polycyclic aromatic hydrocarbon (PAH)-degrading bacteria from marine sediments were enriched and maintained in a fluidized-bed reactor (FBR). The FBR was continuously fed a mixture of naphthalene, biphenyl, 2-methylnaphthalene, 2,6-dimethylnaphthalene, acenaphthene, fluorene, and phenanthrene; and the effluent concentrations remained below 0.03 mg/L (detection limit) over a period of 6 months. In batch vial assays, the relative rates of PAH degradation were controlled by their solubilities and, in some cases, by their substitution patterns. The enrichment also degraded several other PAHs, including anthracene and pyrene. The results demonstrate that the predominant PAH constituents of coal-tar creosote can be degraded and that PAH-contaminated saline waters can be remediated by the marine enrichment.

Melin, E.S.; Puhakka, J.A. [Tampere Univ. of Technology (Finland); Maennistoe, M. [Helsinki Univ. of Technology (Finland); Ferguson, J.F. [Univ. of Washington, Seattle, WA (United States). Dept. of Civil Engineering

1995-12-31

410

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

NASA Technical Reports Server (NTRS)

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

Rollbuhler, R. J.

1982-01-01

411

Circulating Fluidized Bed Combustion Boiler Project  

E-print Network

nonmechanical seal to achieve high raw material efficiency. Solids too small to drop out in the hot cyclone collector are carried to the baghouse for final p rticulate removal from the cooled gas stream before it is discharged to the atmosphere. Residue... is removed from the bottom of the combustion chamber as bottom ash and from the baghouse as fly ash. A portion of the heat is absorbed in the combustion chamber, and the remaining heat is recovered in the convection section of the boiler...

Farbstein, S. B.; Moreland, T.

1984-01-01

412

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

SciTech Connect

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

Nsakala ya Nsakala; Gregory N. Liljedahl

2003-05-15

413

CFD Analysis of Bubbling Fluidized Bed Using Rice Husk  

NASA Astrophysics Data System (ADS)

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

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

414

Single-stage fluidized-bed gasification. [Peat  

SciTech Connect

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. All process steams are measured and sampled for data analysis. A total of 24 tests have been conducted in this unit; detailed results of all tests have been published. Peats from Minnesota, Maine, and North Carolina were tested. Tables 1 and 2 summarize the operating ranges used and the product yields achieved in these tests. A wide range of operating conditions was tested. The following discussion of results is directed toward the Minnesota peat tests. Several conclusions can be drawn: high peat conversions (> 90%) can be achieved under relatively mild conditions. Pressure has no apparent effect on conversion. Low oil yields, less than 1% of the feed carbon, were obtained as expected with the bottom feed configuration. External steam feed was not required to achieve high carbon conversions. Apparently, sufficient reaction steam is produced during peat devolatilization.

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

1982-04-01

415

Wall-to-suspension heat transfer in circulating fluidized beds  

SciTech Connect

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

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

1995-12-31

416

Maltodextrin hydrolysis in a fluidized-bed immobilized enzyme reactor  

SciTech Connect

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

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

1986-02-01

417

The backflow cell model for fluidized bed catalytic reactors  

E-print Network

of the solids elimi. nate hot spots and allow good control of the temperature of the system; 2. The large solid-gas contact area and good contact between these phases make this an efficient system for surface controlled re- actions; 3. The ease of handling... of phase. Thus, a fluidized bed may be considered to be composed of two phases. One is a continuous (dense, heavy, or emulsion) phase and con- sists of uniformly distributed solid particles in a sup- porting gas stream. The second is a di. scontinuous...

Ganapathy, E. V

2012-06-07

418

Fluidized bed incineration process design for transuranic waste  

SciTech Connect

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

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

1980-07-19

419

Feasibility of rotating fluidized bed reactor for rocket propulsion  

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

420

Standby cooling system for a fluidized bed boiler  

DOEpatents

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

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

1990-01-01

421

Steady State Sedimentation in a Liquid Fluidized Bed  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

422

Dynamical Simulation of Fluidized Beds --- Hydrodynamically Interacting Granular Particles  

E-print Network

A numerical simulation of a gas-fluidized bed is performed without introduction of any empirical parameters. Realistic bubbles and slugs are observed in our simulation. It is found that the convective motion of particles is important for the bubbling phase and there is no convection in the slugging phase. From the simulation results, non-Gaussian distributions are found in the particle velocities and the relation between the deviation from Gaussian and the local density of particles is suggested. It is also shown that the power spectra of particle velocities obey power laws. A brief explanation on the relationship between the simulation results and the Kolmogorov scaling argument is discussed.

Kengo Ichiki; Hisao Hayakawa

1995-02-28

423

Analysis of gas flow rate variation on fluidized bed combustor  

NASA Astrophysics Data System (ADS)

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

Surjosatyo, Adi; Tama, Adhika Anindita

2012-06-01

424

A Two-Stage Microbial Fuel Cell and Anaerobic Fluidized Bed Membrane Bioreactor (MFC-AFMBR) System for Effective Domestic  

E-print Network

A Two-Stage Microbial Fuel Cell and Anaerobic Fluidized Bed Membrane Bioreactor (MFC-AFMBR) System treatment process, consisting of microbial fuel cells and an anaerobic fluidized bed membrane bioreactor

425

Author's personal copy Atomic layer deposition of iron(III) oxide on zirconia nanoparticles in a fluidized bed  

E-print Network

in a fluidized bed reactor using ferrocene and oxygen Jonathan R. Scheffe a , Andrea Francés a,c , David M. King (26 nm) in a fluidized bed reactor by atomic layer deposition. Ferrocene and oxygen were alternately

George, Steven M.

426

Survey of long time behavior and costs of industrial fluidized bed heat exchangers  

Microsoft Academic Search

In many cases of severe fouling and\\/or scaling of conventional heat exchangers fluidized bed heat exchangers can be expected to operate continuously with clean tube walls. Especially advantageous are circulating fluidized beds due to their wide range of process stability. But internal particle circulation is inevitably connected to backmixing of the fluid and, as a consequence, losses of mean driving

Robert Rautenbach; Torsten Katz

1997-01-01

427

Drying Kinetics in the Riser of Circulating Fluidized Bed with Internals  

Microsoft Academic Search

Solid particles were dried in the riser of circulating fluidized bed with internals to study the drying kinetics. Experiments were conducted in a circulating fluidized bed, having perforated plates as internals covering wide range in the operating parameters. The effects of various operating parameters, i.e., initial moisture content, temperature, and flow rate, of the heating medium and solid circulation rate

N. Balasubramanian; C. Srinivasakannan; C. Ahmed Basha

2007-01-01

428

A FEM model of conventional hot dipping coating process by using a fluidized bed  

Microsoft Academic Search

A FEM model of a conventional hot dipping fluidized bed (FB) coating process on a low carbon steel rod using a PPA thermoplastic powder was developed. Two computational domains, the former for the metal substrate and the growing coating and the latter for fluidized bed emulsion nearby the metal substrate were set. A novel recursive procedure was employed to solve

M. Barletta; G. Simone; V. Tagliaferri

2005-01-01

429

Multiple modes of bed mass oscillation in gas-solids fluidized beds  

SciTech Connect

The oscillation of gas-solids fluidized beds is a well investigated phenomenon. Knowledge of the amplitude and frequency of bed mass oscillations is necessary for the design of fluidized beds. Furthermore, these oscillations influence gas bubble behavior and, consequently, the overall chemical performance of the fluidized bed. The dynamics of a 0.80 cm ID gas-solids fluidized bed have been investigated by frequency analysis of measured in-bed pressure fluctuations. The peak frequency of the power spectral density is determined as a function of gas velocity (0--1 m/s), bed height (0.23--2.19 m), and measurement position (0.14--2.19 m, opposite positions). For a fixed experimental condition and fixed measurement position, multiple dominant peak frequencies are observed, corresponding to different modes of oscillation. The peak frequency is a weak function of gas velocity. The existence of multiple oscillation modes is not predicted by relationships presented in literature, which typically allow only a single natural frequency of fluidized bed oscillation. A previously derived relationship for the sloshing frequency of gas-liquid fluidized beds adequately describes the gas-solids fluidized bed data presented in this paper and explains the existence of multiple, alternating oscillation modes occurring at fixed experimental conditions. The presence of different oscillatory motions for the fluidized bed were confirmed by visual observation of the bed surface.

Schaaf, J. van der; Schouten, J.C.; Bleek, C.M. van den; Johnsson, F.

1999-07-01

430

Acoustic effects during the combustion of gaseous fuels in a bubbling fluidized bed  

Microsoft Academic Search

Acoustic effects accompany the combustion of gaseous fuels in bubbling fluidized beds of inert materials. In an exploratory study of this effect, using a laboratory-size fluidized bed in which a mixture of propane and butane was burned, the bed’s temperature was monitored continuously and the acoustic effects were recorded. The temperature ranges over which combustion was “noisy” and “quiet” were

W. ?ukowski

1999-01-01

431

An examination of the exothermic nature of fluidized bed combustion (FBC) residues  

Microsoft Academic Search

Circulating fluidized bed combustion (CFBC) ashes from nine operational periods at the 183 MWe CFBC boiler at Point Aconi were examined for exothermic behaviour. Bed ashes and fly ashes were investigated using a Parr 1455 solution calorimeter. Limited tests were also carried out with additional samples from Point Aconi and from the 160 MWe TVA Bubbling Fluidized Bed Combustion boiler

E. J. Anthony; L. Jia; M. Caris; F. Preto; S. Burwell

1999-01-01

432

New design equations for liquid\\/solid fluidized bed heat exchangers  

Microsoft Academic Search

Liquid\\/solid fluidized bed heat exchangers have originally been developed for desalination plants. However, due to their substantial benefits with respect to significantly improved heat transfer and fouling reduction, successful applications also exist in areas such as petrochemical, minerals and food processing as well as in the paper and power industries. The excellent performance of fluidized bed heat exchangers is related

M. Aghajani; H. Müller-Steinhagen; M. Jamialahmadi

2005-01-01

433

A theoretical investigation of gas–solid flow exiting a fluidized bed into a standpipe  

Microsoft Academic Search

A theoretical solution for a two-dimensional steady flow of a gas–solid mixture exiting a fluidized bed into a vertical standpipe is presented. Initially, analytical expressions for the particle velocity and gas pressure are obtained inside the fluidized bed and standpipe, assuming that changes in the mixture density are negligible. For inertial dominated flow regimes it is shown that the gas

S. C. Tsinontides

1999-01-01

434

A bubbling fluidized bed solar reactor model of biomass char high temperature steam-only gasification  

Microsoft Academic Search

A two phase biomass char (biochar) steam gasification model based on the systems kinetics is developed in a bubbling fluidized bed with concentrated solar heat as source of energy. The model calculates the dynamic and steady state profiles, as well as the complex parameters of fluidized beds. This robust model is capable of predicting the temperature and concentration profiles of

E. D. Gordillo; A. Belghit

2011-01-01

435

Foam Control using a Fluidized Bed of Hydrophobic Particles by Clara Mata*  

E-print Network

Foam Control using a Fluidized Bed of Hydrophobic Particles by Clara Mata* & D. D. Joseph different tests (particle-induced film rupture and foam shake test), but they did not use a fluidized bed may be strongly suppressed by fluidizing hydrophilic particles in the bubbly mixture below the foam

Joseph, Daniel D.

436

Nanocoating individual cohesive boron nitride particles in a fluidized bed by ALD  

E-print Network

Nanocoating individual cohesive boron nitride particles in a fluidized bed by ALD Jeffrey R. Wank analysis. While fluidizing, fine BN particles aggregate in the bed. The aggregates are the entities that cohesive primary particles that fluidize as aggregates in a fluidized bed can be individually coated

George, Steven M.

437

Particle coating by chemical vapor deposition in a fluidized bed reactor  

Microsoft Academic Search

Aluminum coatings were created onto glass beads by chemical vapor deposition in a fluidized bed reactor at different temperatures. Nitrogen was enriched with Triisobutylaluminum (TIBA) vapor and the latter was thermally decomposed inside the fluidized bed to deposit the elemental aluminum. To ensure homogeneous coating on the bed material, the fluidizing conditions necessary to avoid agglomeration were investigated for a

Gregor Czok; Joachim Werther

2005-01-01

438

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

Microsoft Academic Search

The purpose of this project is to determine the physical and chemical reactions which lead to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed boilers is in progress. Preliminary results indicate that at least five boilers were experiencing some

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

1993-01-01

439

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

PubMed Central

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

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

2013-01-01

440

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

SciTech Connect

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

Gomes, E.O.; Lora, E.S. [Universidad de Oriente, Santiago (Cuba); Cortez, L.A.B. [DCR/FEAGRI/UNICAMP, Campinas (Brazil)

1995-11-01

441

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

SciTech Connect

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

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

1984-03-01

442

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

PubMed

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

Calvo, L F; García, A I; Otero, M

2013-01-01

443

The local heat transfer mathematical model between vibrated fluidized beds and horizontal tubes  

SciTech Connect

A dimensionless mathematical model is proposed to predict the local heat transfer coefficients between vibrated fluidized beds and immersed horizontal tubes, and the effects of the thickness of gas film and the contact time of particle packets are well considered. Experiments using the glass beads (the average diameter bar d{sub p}=1.83mm) were conducted in a two-dimensional vibrated fluidized bed (240 mm x 80 mm). The local heat transfer law between vibrated fluidized bed and horizontal tube surface has been investigated. The results show that the values of theoretical prediction are in good agreement with experimental data, so the model is able to predict the local heat transfer coefficients between vibrated fluidized beds and immersed horizontal tubes reasonably well, and the error is in range of {+-}15%. The results can provide references for future designing and researching on the vibrated fluidized beds with immersed horizontal tubes. (author)

Zhu, Xuejun [School of Chemical Engineering, Sichuan University, Chengdu 610065 (China); College of Biology and Chemical Engineering, Panzhihua University, Panzhihua 617000 (China); Ye, Shichao; Pan, Xiaoheng [School of Chemical Engineering, Sichuan University, Chengdu 610065 (China)

2008-05-15

444

CO2 Capture using Dry Potassium-Based Sorbents in a Bubbling Fluidized-Bed Reactor  

NASA Astrophysics Data System (ADS)

A bubbling fluidized-bed reactor was used to study the CO2 capture characteristics of dry potassium-based sorbents. Potassium-based sorbentswere prepared by impregnation with potassium carbonate on supports such as cocoanut activated charcoal (AC#1), coal active carbon (AC#2), activated alumina (Al2O3), silica gel (SG) and diatomite. Sorbents such as K2CO3/AC#1, K2CO3/AC#2, and K2CO3/A12O3 showed excellent carbonation capacity, the conversion rates of those sorbentswere 92.5%, 85.1%, and 88.2%, respectively. The regenerationrates of those sorbents were 87.1%, 83.9% and 86.7%, respectively. SEM and N2 adsorption tests showed that the surface area and pore volume of those sorbents were 669 m2 g-1, 390 m2 g-1, 139 m2/g, and 0.08 cm3/g, 0.17 cm3/g, 0.34 cm3/g, respectively. The particle morphologies of those sorbents are propitious to the carbonation reaction. However, K2CO3/diatomite andK2CO3/SG showed poor carbonation capacity, the conversion conversionswere only 2.0% and 1.9%, respectively.The surface area and pore volume of two sorbents were 1.1 m2/g, 39 m2/g and 0.004 cm3, 0.33 cm3/g, respectively. The carbonation capacity is affectedby the particle morphology of those sorbents. The present work has provided data base for designing and operating a large scale CO2 capture process with two fluidized-bed reactors.

Zhao, C. W.; Chen, X. P.; Zhao, C. S.

445

Fluidized bed material as a lime substitute and calcium source for apple seedlings  

SciTech Connect

Fluidized bed material (FBM), a dry, high-Ca, alkaline waste product from the combustion of coal and limestone, was used as a lime substitute/Ca source for York Imperial apple seedlings (Malus domestica) grown on three acidic soil materials in the greenhouse. Application rates were based on the lime requirement (LR) for each soil material determined by the BaCl/sub 2/, triethanolamine procedure. The LR values were 4.57, 12.54, and 11.65 mt CaCO/sub 3//ha for the Galestown Ap, Arendtsville Ap, and Tatum subsoil soil materials, respectively. Actual rates of FBM were one, two, four, and eight times the LR on a weight basis. A CaCO/sub 3/ treatment at the LR and a non-Ca amended fertilized control were used as comparisons. Fluidized bed material applied at the LR significantly increased leaf and stem dry weights and linear growth after 17 weeks, while the CaCO/sub 3/ treatment was not significantly different from the control. However, the highest FBM rate significantly reduced growth. The reason for this reduced growth was not evident from tissue elemental analyses or measurements of various soil properties. Applied FBM significantly increased leaf and stem Ca levels and decreased Zn nd Mn concentrations. Soils pH and electrical conductivities were elevated as were neutral 1N NH/sub 4/OAc extractable Ca levels with increasing FBM rates. Extractable soil Al, Zn, and Mn were reduced with increasing FBM. Approximately four times as much FBM was required to achieve final soil pH values equivalent to the CaCO/sub 3/ treatment applied at the LR.

Korcak, R.F.

1980-01-01

446

Plasma spouted/fluidized bed for materials processing  

NASA Astrophysics Data System (ADS)

Plasma when coupled with spout/fluidized bed reactor for gas-solid reaction brings in several advantages such as high rate of heat and mass transfer, generation of high bulk temperature using a thin jet of plasma itself as a heat source. The science and technology of plasma and fluidization or spouted bed are well established except of these two put together for high temperature application. Plasma heating of fluid/ spouted bed can bring down the size of the equipment and increase the productivity. However the theory and practice of the hybrid technology has not been tested in a variety of applications that involves high temperature synthesis of materials, TRISO particle coating for nuclear fuel particle, thermal decomposition of refractory type ore, halogenations of minerals, particulate processes and synthesis of advanced materials. This paper gives an account of the use and exploitation of plasma coupled with spouted/ fluidized bed especially for material processing and also addresses the issues for adapting the same in the era of developing advanced high temperature materials.

Sathiyamoorthy, D.

2010-02-01

447

Evaluation of Fluidized Beds for Mass Production of IFE Targets  

SciTech Connect

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

Huang, H.; Vermillion, B.A.; Brown, L.C.; Besenbruch, G.E.; Goodin, D.T.; Stemke, R.W.; Stephens, R.B. [General Atomics (United States)

2005-01-15

448

Fluidized-bed combustion and gasification of biomass  

SciTech Connect

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

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

1981-01-01

449

Statistical pyrometric sizing of particles in fluidized bed combustion  

SciTech Connect

A theoretical basis is presented for the concept of statistical pyrometric particle sizing (SPPS) in fluidized bed combustion (FBC). The theory makes it possible to obtain the size distributions for observable particles within given temperature ranges, and thus a statistical estimate can be made of the dependence of the temperature of a fuel particle on its size during FBC. The SPPS method has been experimentally validated by comparison with an independent reference method in a miniature fluidized bed reactor. Graphite spheres were burned one by one and measurements were taken with a two-color fiber-optic pyrometer. Pyrometric signals were obtained many times during each particle`s combustion and SPPS was applied to the results. The generation of CO{sub 2} was also recorded and the evolution of the particle`s size with time was determined from the CO{sub 2} mass balance, assuming shrinking core combustion. The average sizes determined by SPPS and also from the CO{sub 2} mass balance were in good agreement for all temperature ranges. The elevation of the particle`s temperature above that of the bed varied between 20 and about 200 C.

Heino, P.; Hernberg, R.; Stenberg, J. [Tampere Univ. of Technology (Finland)] [Tampere Univ. of Technology (Finland)

1997-02-01

450

Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds  

SciTech Connect

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

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

2008-02-29

451

Conceptual design of commercial oil shale plants, fluidized bed retorting of Colorado oil shale: Alternate design study: Topical report  

Microsoft Academic Search

A conceptual design and cost estimate were developed for an integrated oil shale process plant based on fluidized-bed retorting of Colorado oil shale with lift pipe combustion of retorted shale. The present study incorporates an alternate design for the fluidized-bed retorting system, similar to the configuration employed in fluid catalytic cracking designs. The modified retort design, which employs fluidized bed

P. Albulescu; G. Mazzella

1987-01-01

452

arXiv:cond-mat/0511322v114Nov2005 Glass transition in a fluidized bed of hard spheres  

E-print Network

arXiv:cond-mat/0511322v114Nov2005 Glass transition in a fluidized bed of hard spheres Daniel I of Texas at Austin, Austin, TX 78712 (Dated: November 14, 2005) We demonstrate that a fluidized bed of hard motion arrested) by application of a small increase in flow rate. Thus a fluidized bed can serve

Weeks, Eric R.

453

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

SciTech Connect

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

Bland, A.E.; Brown, T.H. [Western Research Inst., Laramie, WY (United States)

1996-12-31

454

Fluidized coal combustion  

NASA Technical Reports Server (NTRS)

Fluidized-bed coal combustion process, in which pulverized coal and limestone are burned in presence of forced air, may lead to efficient, reliable boilers with low sulfur dioxide and nitrogen dioxide emissions.

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

1979-01-01

455

Kinetics of fluidized bed combustion of wood pellets  

SciTech Connect

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

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

1999-07-01

456

Continuous fluidized-bed contactor with recycle of sorbent  

DOEpatents

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

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

1996-01-01

457

Brewery wastewater treatment using anaerobic inverse fluidized bed reactors.  

PubMed

Two anaerobic inverse fluidized bed reactors were utilized to evaluate organic matter removal from brewery wastewater, applying different OLR and testing two support materials. Hydrodynamic tests varying liquid flow and solid concentration were developed on the supports in order to establish operational conditions. A batch colonization stage was applied using 25% active volume of extendosphere and triturated polyethylene as support materials. The reactors were subsequently operated continuously with stepwise increments in organic loading rate until limiting conditions was reached. For the supports studied, IFBR technology was suitable for organic matter removal present in brewery wastewater with COD removal efficiencies greater than 90%. The reactor with triturated polyethylene support showed an excellent COD removal with OLR values up to 10 g COD/Ld, whereas the reactor with extendosphere support had an excellent hydrodynamic and biologic behavior working with OLR values up to 70 g COD/Ld. PMID:17716891

Alvarado-Lassman, A; Rustrián, E; García-Alvarado, M A; Rodríguez-Jiménez, G C; Houbron, E

2008-05-01

458

Anaerobic fluidized bed reactor application to tropical fruit wine effluent.  

PubMed

The influence of the organic loading rate (OLR), the fluidization level (FL) and the particle diameter of natural zeolite used as support (D(p)), was evaluated at a laboratory scale anaerobic fluidized bed reactor (AFBR), treating tropical fruit wine effluent (vinasse). The experiment was carried out at an OLR from 2-5 kg COD/m3 d, FL of 20 and 40% and D(p) from 0.25 to 0.80 mm. It was demonstrated that OLR and FL had a slight influence on chemical oxygen demand removal and strong influence on the methane production rate. The COD removal was slightly higher for the higher particle diameter used. Additionally using the scanning electron microscope (SEM), it was observed that natural zeolites have excellent physical characteristics as a support medium in AFBR. PMID:17849975

Fernández, N; Montalvo, S; Guerrero, L; Sánchez, E; Cortés, I; Travieso, L

2007-01-01