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Sample records for bench-scale pressurized fluidized-bed

  1. Performance of a bench-scale fast fluidized bed carbonator

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll

    2014-01-01

    The carbonate looping process is a promising technology for CO2 capture from flue gas. In this process, the CO2 capture efficiency depends on the performance of a carbonator that may be operated as a circulating fluidized bed (CFB). In this paper, the carbonator performance is investigated...... by applying a new experimental method with accurate control of the particle recirculation rate. The experimental results show that the inlet calcium to carbon molar ratio is the main factor on the CO2 capture efficiency in the carbonator, that is, increasing the inlet Ca/C from 4 to 13 results in increasing...... the CO2 capture efficiency from 40 to 85% with limestone having a maximum CO2 capture capacity of only 11.5%. Furthermore, a reactor model for a carbonator is developed based on the Kunii-Levenspiels model. A key parameter in the model is the particle distribution along the height of the reactor, which...

  2. Rapid pyrolysis of wheat straw in a Bench-Scale circulating Fluidized-Bed downer reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ding, T. [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (China); Graduate School of Chinese Academy of Sciences, Beijing (China); Li, S.; Xie, J.; Song, W.; Yao, J.; Lin, W. [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (China)

    2012-12-15

    The effects of acid washing treatment on the pyrolysis product distribution and product properties were investigated in a bench-scale circulating fluidized-bed (CFB) downer reactor with wheat straw as feedstock. The acid treatment not only removes most of the inorganic species present in the biomass but also alters the distribution of the remaining organic constituents. It was found that the removal of the inorganic species increases the yield of liquid product and reduces char formation and gas yield. CO and CO{sub 2} are the dominant components in the gaseous product, accounting for over 90 %. The concentration of CO in the gaseous product increases after acid treatment, while the CO{sub 2} concentration decreases. The oxygen and water contents in the liquid product are decreased on acid treatment, leading to a relatively high heating value and viscosity. More volatiles can be found in the char derived from the acid-treated wheat straw than from the raw wheat straw. This may suggest that a longer residence time is needed for pyrolysis of the acid-treated wheat straw in order to obtain the maximal yield of volatile matter. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Particle pressures in fluidized beds. Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-09-01

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

  4. Particle Pressures in Fluidized Beds. Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-09-01

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

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

    Science.gov (United States)

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

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

  6. Immobilized lysozyme for the continuous lysis of lactic bacteria in wine: Bench-scale fluidized-bed reactor study.

    Science.gov (United States)

    Cappannella, Elena; Benucci, Ilaria; Lombardelli, Claudio; Liburdi, Katia; Bavaro, Teodora; Esti, Marco

    2016-11-01

    Lysozyme from hen egg white (HEWL) was covalently immobilized on spherical supports based on microbial chitosan in order to develop a system for the continuous, efficient and food-grade enzymatic lysis of lactic bacteria (Oenococcus oeni) in white and red wine. The objective is to limit the sulfur dioxide dosage required to control malolactic fermentation, via a cell concentration typical during this process. The immobilization procedure was optimized in batch mode, evaluating the enzyme loading, the specific activity, and the kinetic parameters in model wine. Subsequently, a bench-scale fluidized-bed reactor was developed, applying the optimized process conditions. HEWL appeared more effective in the immobilized form than in the free one, when the reactor was applied in real white and red wine. This preliminary study suggests that covalent immobilization renders the enzyme less sensitive to the inhibitory effect of wine flavans.

  7. Pressurized fluidized-bed combustion technology exchange workshop

    Energy Technology Data Exchange (ETDEWEB)

    ,

    1980-04-01

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

  8. PRESSURE FLUCTUATIONS IN GAS-SOLIDS FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    Hsiaotao Bi; Aihua Chen

    2003-01-01

    Pressure fluctuation data measured in a series of fluidized beds with diameters of 0.05, 0.1, 0.29, 0.60 and 1.56 m showed that the maximum amplitude or standard deviation increased with increasing the superficial gas velocity and static bed height for relatively shallow beds and became insensitive to the increase in static bed height in relatively deep beds. The amplitude appeared to be less dependent on the measurement location in the dense bed. Predictions based on bubble passage, bubble eruption at the upper bed surface and bed oscillation all failed to explain all observed trends and underestimated the amplitude of pressure fluctuations, suggesting that the global pressure fluctuations in gas-solids bubbling fluidized beds are the superposition of local pressure variations, bed oscillations and pressure waves generated from the bubble formation in the distributor region, bubble coalescence during their rise and bubble eruption at the upper bed surface.

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

    Energy Technology Data Exchange (ETDEWEB)

    Graves, R.L.

    1980-09-01

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

  10. In Situ and ex Situ Catalytic Pyrolysis of Pine in a Bench-Scale Fluidized Bed Reactor System

    Energy Technology Data Exchange (ETDEWEB)

    Iisa, Kristiina; French, Richard J.; Orton, Kellene A.; Yung, Matthew M.; Johnson, David K.; ten Dam, Jeroen; Watson, Michael J.; Nimlos, Mark R.

    2016-03-17

    In situ and ex situ catalytic pyrolysis were compared in a system with two 2-in. bubbling fluidized bed reactors. Pine was pyrolyzed in the system with a catalyst, HZSM-5 with a silica-to-alumina ratio of 30, placed either in the first (pyrolysis) reactor or the second (upgrading) reactor. Both the pyrolysis and upgrading temperatures were 500 degrees C, and the weight hourly space velocity was 1.1 h-1. Five catalytic cycles were completed in each experiment. The catalytic cycles were continued until oxygenates in the vapors became dominant. The catalyst was then oxidized, after which a new catalytic cycle was begun. The in situ configuration gave slightly higher oil yield but also higher oxygen content than the ex situ configuration, which indicates that the catalyst deactivated faster in the in situ configuration than the ex situ configuration. Analysis of the spent catalysts confirmed higher accumulation of metals in the in situ experiment. In all experiments, the organic oil mass yields varied between 14 and 17% and the carbon efficiencies between 20 and 25%. The organic oxygen concentrations in the oils were 16-18%, which represented a 45% reduction compared to corresponding noncatalytic pyrolysis oils prepared in the same fluidized bed reactor system. GC/MS analysis showed the oils to contain one- to four-ring aromatic hydrocarbons and a variety of oxygenates (phenols, furans, benzofurans, methoxyphenols, naphthalenols, indenols). High fractions of oxygen were rejected as water, CO, and CO2, which indicates the importance of dehydration, decarbonylation, and decarboxylation reactions. Light gases were the major sources of carbon losses, followed by char and coke.

  11. Phase-Plane Invariant Analysis of Pressure Fluctuations in Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaoliang; HE Rong; Toshiyuki Suda; Junichi Sato

    2007-01-01

    Partial agglomeration is a major problem in fluidized beds. A chaotic analytical method based on the phase-plane invariant of the pressure fluctuations in the fluidized beds has been used to warn of agglomeration at an early stage. Cold tests (no combustion) and hot tests (combustion) in fluidized beds show that the phase-plane invariant of the pressure fluctuations can distinguish the dynamic behavior of fluidized beds with different flow rates in cold tests. With combustion, when the flow rate was kept constant, agglomeration was detected very early by looking at the phase-plane invariant. The phase-plane invariant can be used to distinguish changes in fluidized beds due to changes in the flow rate, agglomeration, or various other factors. Therefore, this reliable agglomeration early warning system can be used for better control of circulating fluidized beds.

  12. Grimethorpe experimental pressurized fluidized-bed combustor: in future energy concepts

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, D.B.

    1979-01-01

    The experimental pressurized fluidized bed combustor project at Grimethorpe, UK, is described. The design of the combustor, which is a pressure vessel containing a furnace, which contains the fluidized bed is discussed. Details of the process, the steam water circuit, the fuel system and method of feeding coal, ash removal during the process, the water treatment plant and plant control are given.

  13. Numerical Studies of the Gas-Solid Hydrodynamics at High Temperature in the Riser of a Bench-Scale Circulating Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Maximilian J. Hodapp

    2012-01-01

    Full Text Available The hydrodynamics of circulating fluidized beds (CFBs is a complex phenomenon that can drastically vary depending on operational setup and geometrical configuration. A research of the literature shows that studies for the prediction of key variables in CFB systems operating at high temperature still need to be implemented aiming at applications in energy conversion, such as combustion, gasification, or fast pyrolysis of solid fuels. In this work the computational fluid dynamics (CFD technique was used for modeling and simulation of the hydrodynamics of a preheating gas-solid flow in a cylindrical bed section. For the CFD simulations, the two-fluid approach was used to represent the gas-solid flow with the k-epsilon turbulence model being applied for the gas phase and the kinetic theory of granular flow (KTGF for the properties of the dispersed phase. The information obtained from a semiempirical model was used to implement the initial condition of the simulation. The CFD results were in accordance with experimental data obtained from a bench-scale CFB system and from predictions of the semiempirical model. The initial condition applied in this work was shown to be a viable alternative to a more common constant solid mass flux boundary condition.

  14. Technical evaluation: pressurized fluidized-bed combustion technology

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wolowodiuk, W.; Robertson, A. [Foster Wheeler Development Corp., Livingston, NJ (United States); Bonk, D. [Dept. of Energy, Morgantown, WV (United States)

    1995-12-01

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

  16. Hot-gas filtration for pressurized fluidized-bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Chang, R.; Kuby, W.

    1984-03-01

    This topical report discusses the status of the work, conducted under EPRI contract 1336-4, on the evaluation and development of ceramic filter hot gas cleanup technology for pressurized fluidized bed combustion. This topical report represents the status of the work through September 1983. The goal of the effort is to achieve 6000 h of operation on a 13-filter durability test rig. The work includes two parallel tasks. The first is construction of a durability test facility, operation of the facility with an initial candidate filter media installed, and assessment of results. The second task includes a literature survey to identify state-of-the-art ceramic fibers suitable for high-temperature gas filtration applications and filter testing in a single-filter test facility to assess the performance of promising new filter media. The best candidate will be chosen for further evaluation in the durability facility.

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

    Science.gov (United States)

    Isaksson, Juhani; Koskinen, Jari

    1995-01-01

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

  18. Advanced high-pressure bench-scale reactor for testing with hot corrosive gases

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Bachta, R.P.; Wangerow, J.R. (Inst. of Gas Technology, Chicago, IL (United States)); Mojtahedi, W.; Salo, K. (Enviropower Inc., Espoo (Finland))

    1994-01-01

    A bench-scale, high-pressure/high-temperature fluidized-bed reactor (HPTR) system is described that is capable of operating at a maximum temperature and pressure of 1,000 C and 30 bar in a corrosive atmosphere. The design of the unit is based on a double-shell balanced-pressure system. All the hot parts of the reactor that are wetted by the corrosive (and/or reactive) gases and the entire sampling line are constructed of inert material to prevent corrosion and loss of the reactant gases. The unit has been used for over 200 high-pressure hot coal gas desulfurization tests at 20 bars and up to 750 C without any experimental problem and with excellent sulfur balance, indicating that this reactor system is ideal for testing with reactive and corrosive gases at elevated pressures and temperatures.

  19. Pressurized fluidized-bed hydroretorting of Eastern oil shales

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.J.; Mensinger, M.C.; Rue, D.M.; Lau, F.S. (Institute of Gas Technology, Chicago, IL (United States)); Schultz, C.W. (Alabama Univ., University, AL (United States)); Parekh, B.K. (Kentucky Univ., Lexington, KY (United States)); Misra, M. (Nevada Univ., Reno, NV (United States)); Bonner, W.P. (Tennessee Technological Univ., Cookeville, TN (United States))

    1992-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-03-29

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

  1. Insights in hydrodynamics of bubbling fluidized beds at elevated pressure by DEM-CFD approach

    Institute of Scientific and Technical Information of China (English)

    Zahra Mansourpour; Sedighe Karimi; Reza Zarghami; Navid Mostoufi; Rahmat Sotudeh-Gharebagh

    2010-01-01

    A numerical simulation was conducted to study the effect of pressure on bubble dynamics in a gas-solid fluidized bed. The gas flow was modeled using the continuum theory and the solid phase, by the dis-crete element method (DEM). To validate the simulation results, calculated local pressure fluctuations were compared with corresponding experimental data of 1-mm polyethylene particles. It was shown that the model successfully predicts the hydrodynamic features of the fluidized bed as observed in the experiments. Influence of pressure on bubble rise characteristics such as bubble rise path, bubble sta-bility, average bubbles diameter and bubble velocity through the bed was investigated. The simulation results are in conformity with current hydrodynamic theories and concepts for fluidized beds at high pressures. The results show further that elevated pressure reduces bubble growth, velocity and stability and enhances bubble gyration through the bed, leading to change in bed flow structure.

  2. A Novel Atmospheric Pressure Plasma Fluidized Bed and Its Application in Mutation of Plant Seeds

    Institute of Scientific and Technical Information of China (English)

    CHEN Guang-Liang; WANG Zhen-Quan; HAN Er-Li; FU Ya-Bo; YANG Si-Ze; FAN Song-Hua; LI Chun-Ling; GU Wei-Chao; FENG Wen-Ran; ZHANG Gu-Ling; WANG Jiu-Li; Latif K.; ZHANG Shu-Gen

    2005-01-01

    @@ An atmospheric pressure plasma fluidized bed (APPFB) is designed to generate plasma using a dielectric barrier discharge (DBD) with one liquid electrode. In the APPFB system, the physical properties of DBD discharge and its application in plant-seed mutating are studied fundamentally. The results show that the generated plasma is a typical glow discharge free from filament and arc plasma, and the macro-temperature of the plasma fluidized bed is nearly at room temperature. There are no obvious changes in the pimientos when their seeds are treated by APPFB, but great changes are found for coxcombs.

  3. STUDY ON THE OVERALL PRESSURE BALANCE OF A DOWNFLOW CIRCULATING FLUIDIZED BED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Hengzhi Chen; Dawei Yang; Hongzhong Li; Shiyu Tan

    2006-01-01

    A pressure balance model for a circulating fluidized bed unit that incorporates a downer has been proposed. The model predictions were validated with the experimental data obtained from a special cold-model circulating fluidized bed. Comparison of the operation stability between a CFB downer and a CFB riser has been carried out. Only one critical gas velocity exists in the CFB-riser for a given riser solids flux, while there can be many critical gas velocities for the operation of a CFB downer. Therefore, it is possible to achieve high solids concentration in a CFB downer if appropriate operating conditions are used.

  4. Similarity between chaos analysis and frequency analysis of pressure fluctuations in fluidized beds

    NARCIS (Netherlands)

    van der Schaaf, J; van Ommen, [No Value; Takens, F; Schouten, JC; van den Bleek, CM

    2004-01-01

    In literature the dynamic behavior of fluidized beds is frequently characterized by spectral analysis and chaos analysis of the pressure fluctuations that are caused by the gas-solids flow. In case of spectral analysis, most often the power spectral density (PSD) function is quantified, for example,

  5. Comparisons of Fly Ash and Deposition Between Air and Oxy-Fuel Combustion in Bench-Scale Fluidized Bed with Limestone Addition

    Institute of Scientific and Technical Information of China (English)

    Zhimin Zheng; Hui Wang∗; Yongjun Guo; Li Yang; Shuai Guo; Shaohua Wu

    2015-01-01

    In Oxy⁃fuel circulating fluidized bed, the residual CaO particles may react with high concentration of CO2 in flue gas to form bonded deposit on heat transfer surfaces in backpass when limestone is used as a sorbent to capture SO2 .In this paper, experiments were designed on ash deposition in a bench⁃scale fluidized bed under oxy⁃fuel and air atmosphere. A novel ash deposit sampling probe was used to simulate the tubes of tail surfaces. The chemical composition of fly ash and ash deposit from both air⁃firing and oxy⁃fuel firing cases were analyzed by Inductively Coupled Plasma⁃Atomic Emission Spectrometry ( ICP⁃AES ) and Scanning Electron Microscopy ( SEM) , respectively. The degrees of carbonation reaction of ash deposits were measured by Thermo Gravimetric Analysis. The results showed that there are distinct differences in fly ash deposition rate between oxy⁃fuel and air firing cases, and oxy⁃fuel combustion with limestone addition can affect chemical composition of fly ash and ash deposit, especially for elements of Ca, Na, K, and S. However, the carbonation reaction degree of ash deposits is found weak, which is due to the relatively low CaO content in ash deposit or not long enough of the sampling time.

  6. Combustion Characteristics of Lignite Char in a Laboratory-scale Pressurized Fluidized Bed Combustor

    Science.gov (United States)

    Murakami, Takahiro; Suzuki, Yoshizo

    In a dual fluidized bed gasifier, the residual char after steam gasification is burnt in riser. The objectives of this work are to clarify the effect of parameters (temperature, pressure, and particle size of lignite char) of char combustion using a laboratory-scale pressurized fluidized bed combustor (PFBC). As a result, the burnout time of lignite char can be improved with increasing operating pressure, and temperature. In addition, the decrease in the particle size of char enhanced the effect on burnout time. The initial combustion rate of the char can be increased with increasing operating pressure. The effect was decreased with increasing operating temperature. However, the effect of operating pressure was slightly changed in small particle size, such as 0.5-1.0 mm. It takes about 20 sec to burn 50% of char in the operating pressure of 0.5 MPa and the particle size of 0.5-1.0 mm.

  7. Wavelet analysis of pressure fluctuation signals in a gas-solid fluidized bed

    Institute of Scientific and Technical Information of China (English)

    甄玲; 王晓萍; 黄海; 陈伯川; 黄春燕

    2002-01-01

    It has been shown that much dynamic information is hidden in the pressure fluctuation signals of a gas-solid fluidized bed. Unfortunately, due to the random and capricious nature of this signal, it is hard to realize reliable analysis using traditional signal processing methods such as statistical analysis or spectral analysis, which is done in Fourier domain. Information in different frequency band can be extracted by using wavelet analysis. On the evidence of the composition of the pressure fluctuation signals, energy of low frequency (ELF) is proposed to show the transition of fluidized regimes from bubbling fluidization to turbulent fluidization. Plots are presented to describe the fluidized bed's evolution to help identify the state of different flow regimes and provide a characteristic curve to identify the fluidized status effectively and reliably.

  8. Development of pressurized internally circulating fluidized bed combustion technology; Kaatsu naibu junkan ryudosho boiler no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, I. [Center for Coal Utilization, Japan, Tokyo (Japan); Nagato, S.; Toyoda, S. [Ebara Corp., Tokyo (Japan)

    1996-09-01

    The paper introduced support research on element technology needed for the design of hot models of the pressurized internally circulating fluidized bed combustion boiler in fiscal 1995 and specifications for testing facilities of 4MWt hot models after finishing the basic plan. The support research was conduced as follows: (a) In the test for analysis of cold model fluidization, it was confirmed that each characteristic value of hot models is higher than the target value. Further, calculation parameters required for computer simulation were measured and data on the design of air diffusion nozzle for 1 chamber wind box were sampled. (b) In the CWP conveyance characteristic survey, it was confirmed that it is possible to produce CWP having favorable properties. It was also confirmed that favorable conveyability can be maintained even if the piping size was reduced down to 25A. (c) In the gas pressure reducing test, basic data required for the design of gas pressure reducing equipment were sampled. Specifications for the fluidized bed combustion boiler of hot models are as follows: evaporation amount: 3070kg/h, steam pressure: 1.77MPa, fuel supply amount: 600kg-coal/h, boiler body: cylinder shape water tube internally circulating fluidized bed combustion boiler. 4 refs., 4 figs.

  9. Study on the nature of pressure signals in a bubbling fluidized bed

    Institute of Scientific and Technical Information of China (English)

    赵贵兵; 陈纪忠; 阳永荣

    2002-01-01

    In this study on the nature of pressure signals generated by a determi nistic or stochastic process in a bubbling fluidized bed, pressure fluctuation m easurements were carried out in a 300-mm-diamet column at 0.090 m and 0.40 m above the distributor for different gas velocities. The method of detecting determinis tic dynamic underlying pressure signals is proposed on the basis of predictabili ty of pressure fluctuations. The deterministic nature of dynamics in fluidizing system was verified. The deterministic level of dynamics in fluidizing system wa s analyzed for different locations of pressure measurements and different gas ve locities.

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

    Science.gov (United States)

    Sweeney, Daniel Joseph

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

  11. RADIOACTIVE DEMONSTRATION OF FINAL MINERALIZED WASTE FORMS FOR HANFORD WASTE TREATMENT PLANT SECONDARY WASTE BY FLUIDIZED BED STEAM REFORMING USING THE BENCH SCALE REFORMER PLATFORM

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C.; Burket, P.; Cozzi, A.; Daniel, W.; Jantzen, C.; Missimer, D.

    2012-02-02

    The U.S. Department of Energy's Office of River Protection (ORP) is responsible for the retrieval, treatment, immobilization, and disposal of Hanford's tank waste. Currently there are approximately 56 million gallons of highly radioactive mixed wastes awaiting treatment. A key aspect of the River Protection Project (RPP) cleanup mission is to construct and operate the Waste Treatment and Immobilization Plant (WTP). The WTP will separate the tank waste into high-level and low-activity waste (LAW) fractions, both of which will subsequently be vitrified. The projected throughput capacity of the WTP LAW Vitrification Facility is insufficient to complete the RPP mission in the time frame required by the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement (TPA), i.e. December 31, 2047. Therefore, Supplemental Treatment is required both to meet the TPA treatment requirements as well as to more cost effectively complete the tank waste treatment mission. In addition, the WTP LAW vitrification facility off-gas condensate known as WTP Secondary Waste (WTP-SW) will be generated and enriched in volatile components such as {sup 137}Cs, {sup 129}I, {sup 99}Tc, Cl, F, and SO{sub 4} that volatilize at the vitrification temperature of 1150 C in the absence of a continuous cold cap (that could minimize volatilization). The current waste disposal path for the WTP-SW is to process it through the Effluent Treatment Facility (ETF). Fluidized Bed Steam Reforming (FBSR) is being considered for immobilization of the ETF concentrate that would be generated by processing the WTP-SW. The focus of this current report is the WTP-SW. FBSR offers a moderate temperature (700-750 C) continuous method by which WTP-SW wastes can be processed irrespective of whether they contain organics, nitrates, sulfates/sulfides, chlorides, fluorides, volatile radionuclides or other aqueous components. The FBSR technology can process these wastes into a crystalline

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

    Energy Technology Data Exchange (ETDEWEB)

    Archie Robertson

    2003-10-29

    Foster Wheeler Power Group, Inc. is working under US Department of Energy 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% and produce 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 amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building bock that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the July 1--September 30, 2003 time period.

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

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2003-01-30

    Foster Wheeler Power Group, Inc. is working under US Department of Energy 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% and produce 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 amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building bock that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the October 1--December 31, 2002 time period.

  14. Development of Pressurized Circulating Fluidized Bed Partial Gasification Module (PGM)

    Energy Technology Data Exchange (ETDEWEB)

    A. Robertson

    2002-09-30

    Foster Wheeler Power Group, Inc. is working under US Department of Energy 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% and produce 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 amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building bock that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the July 1-September 30, 2002 time period.

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

    Energy Technology Data Exchange (ETDEWEB)

    Archie Robertson

    2003-07-23

    Foster Wheeler Power Group, Inc. is working under US Department of Energy 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% and produce 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 amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building bock that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the April 1--June 30, 2003 time period.

  16. Pressurized fluidized-bed hydroretorting of Eastern oil shales. Progress report, December 1991--February 1992

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-03-01

    The objective is to perform the research necessary to develop the pressurized fluidized-bed hydroretorting (PFH) process for producing oil from Easter oil shales. The program also incorporates research on technologies in areas such as raw shale preparation, beneficiation, product separation, and waste disposal that have the potential of improving the economics and/or environmental acceptability of recovering oil from oil shales using the PFH process. Accomplishments for this period are presented for the following tasks: Testing of Process Improvement Concepts; Beneficiation Research; Operation of PFH on Beneficiated Shale; Environmental Data and Mitigation Analyses; Sample Procurement, Preparation, and Characterization; and Project Management and Reporting. 24 figs., 19 tabs. (AT)

  17. Modelling of NOx emissions from pressurized fluidized bed combustion - A parameter study

    DEFF Research Database (Denmark)

    Jensen, Anker; Johnsson, Jan Erik

    1997-01-01

    Simulations with a mathematical model of a pressurized bubbling fluidized-bed combustor (PFBC) combined with a kinetic model for NO formation and reduction are reported. The kinetic model for NO formation and reduction considers NO and NH3 as the fixed nitrogen species, and includes homogeneous....... The sensitivity of the simulated NO emission with respect to hydrodynamic and combustion parameters in the model is investigated and the mechanisms by which the parameters influence the emission of NO is explained. The analysis shows that the most important hydrodynamic parameters are the minimum fluidization...

  18. Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Beneficiation

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.J.; Lau, F.S.; Mensinger, M.C. (Institute of Gas Technology, Chicago, IL (United States)); Schultz, C.W.; Mehta, R.K.; Lamont, W.E. (Alabama Univ., University, AL (United States)); Chiang, S.H.; Venkatadri, R. (Pittsburgh Univ., PA (United States)); Misra, M. (Nevada Univ., Reno, NV (United States))

    1992-05-01

    The Mineral Resources Institute at the University of Alabama, along with investigators from the University of Pittsburgh and the University of Nevada-Reno, have conducted a research program on the beneficiation, of Eastern oil shales. The objective of the research program was to evaluate and adapt those new and emerging technologies that have the potential to improve the economics of recovering oil from Eastern oil shales. The technologies evaluated in this program can be grouped into three areas: fine grinding kerogen/mineral matter separation, and waste treatment and disposal. Four subtasks were defined in the area of fine grinding. They were as follows: Ultrasonic Grinding, Pressure Cycle Comminution, Stirred Ball Mill Grinding, and Grinding Circuit Optimization. The planned Ultrasonic grinding research was terminated when the company that had contracted to do the research failed. Three technologies for effecting a separation of kerogen from its associated mineral matter were evaluated: column flotation, the air-sparged hydrocyclone, and the LICADO process. Column flotation proved to be the most effective means of making the kerogen/mineral matter separation. No problems are expected in the disposal of oil shale tailings. It is assumed that the tailings will be placed in a sealed pond and the water recycled to the plant as is the normal practice. It may be advantageous, however, to conduct further research on the recovery of metals as by-products and to assess the market for tailings as an ingredient in cement making.

  19. Surface Modification of Fine Particle by Plasma Grafting in a Circulating Fluidized Bed Reactor under Reduced Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sounghee [Woosuk University, Jinchon (Korea, Republic of)

    2015-10-15

    A plasma surface modification of powders has been carried out in a circulating fluidized bed reactor under reduced pressure. Polystyrene (PS) particles treated by plasma are grafted with polyethylene glycol (PEG) on the surface. The virgin, plasma-treated and grafted powders were characterized by DPPH method, FTIR, SEM and contact angle meter. The plasma-treated PS powders have well formed peroxide on the surface, By PEG grafting polymerization, PEG is well grafted and dispersed on the surface of the plasma-treated PS powders. The PEG-g-PS particle was successfully synthesized using the plasma circulating fluidized bed reactor under reduced pressure.

  20. Time series analysis of pressure fluctuation in gas-solid fluidized beds

    Directory of Open Access Journals (Sweden)

    C. Alberto S. Felipe

    2004-09-01

    Full Text Available The purpose of the present work was to study the differentiation of states of typical fluidization (single bubble, multiple bubble and slugging in a gas-solid fluidized bed, using spectral analysis of pressure fluctuation time series. The effects of the method of measuring (differential and absolute pressure fluctuations and the axial position of the probes in the fluidization column on the identification of each of the regimes studied were evaluated. Fast Fourier Transform (FFT was the mathematic tool used to analysing the data of pressure fluctuations, which expresses the behavior of a time series in the frequency domain. Results indicated that the plenum chamber was a place for reliable measurement and that care should be taken in measurement in the dense phase. The method allowed fluid dynamic regimes to be differentiated by their dominant frequency characteristics.

  1. Fluidized bed combustion chamber

    Energy Technology Data Exchange (ETDEWEB)

    Kullendorff, A.; Wikner, J.

    1985-03-25

    The chamber is confined in a pressure vessel. The lower part of the chamber has tilted parallel gutters up to the height of the fluidized bed. The slope of the gutter walls is 5 degrees-15 degrees and the top area of the gutters is 1.3 to 3 times larger than their bottom.

  2. Circulating pressurized fluidized bed. Trial operation, phase 1c. Final report; Zirkulierende Druckwirbelschicht. Versuchsbetrieb, Phase 1c. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Krein, J.; Schmitt, J.; Wedel, G. von; Winkler, K.

    1993-09-01

    Since March `89, the Deutsche Babcock Energie und Umwelttechnik AG have been operating a 15 MW{sub th} experimental pressurized fluidized bed facility. The plant was first designed as a stationary pressurized fluidized bed and was optimized and tested in a 2000-h period of trial operation. In view of the good results of the plant and the technical superiority of the circulating fluidized bed technology, the experimental facility was converted into a circulating pressurized fluidized bed system. The reconstruction work was started in February `91, and from October `91 onwards the circulating pressurized fluidized bed system was optimized and tested in a 900-h trial operation period. This report explains the concept of circulating pressurized fluidized bed technology as applied by the Deutsche Babcock Energie und Umwelttechnik AG and presents the results of circulating trial operation. The results of circulating and stationary fluidized bed trial operation are compared. This comparison is particularly significant as all marginal systems of the plant, i.e. for combustion air supply, flue gas discharge, coal supply and ash removal, have remained unmodified during the reconstruction phase. (orig.) [Deutsch] Seit Maerz `89 betreibt die Deutsche Babcock Energie und Umwelttechnik AG eine 15 MW{sub th} Druckwirbelschicht Versuchsanlage. In einer ersten Versuchsphase wurde die Anlage als stationaere Druckwirbelschicht konzipiert und in einem 2000-stuendigen Versuchsbetrieb optimiert und getestet. Ausgehend von den guten Ergebnissen aus dem stationaeren, druckaufgeladenen Versuchsbetrieb und in Anbetracht der aus dem atmosphaerischen Bereich bekannten Vorteile der zirkulierenden gegenueber der stationaeren Wirbelschicht wurde die Versuchsanlage ab Februar `91 in eine zirkulierende Druckwirbelschicht umgebaut. Ab Oktober `91 wurde die zirkulierende Druckwirbelschicht in einem 900-stuendigen Versuchsbetrieb optimiert und getestet. In diesem Bericht wird das von der Deutsche

  3. Measurements of gas velocity in the freeboard of a pressurized fluidized bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Verloop, W.C. [Lab. for Thermal Power Engineering, Dept. of Mechanical Engineering and Marine Technology, Univ. of Technology, Delft (Netherlands); Hagen, T.H.J.J. van der [Interfaculty Reactor Inst., Dept. of Reactor Physics, Univ. of Technology, Delft (Netherlands); Boersma, D. [Lab. for Thermal Power Engineering, Dept. of Mechanical Engineering and Marine Technology, Univ. of Technology, Delft (Netherlands); Hein, K.R.G. [Lab. for Thermal Power Engineering, Dept. of Mechanical Engineering and Marine Technology, Univ. of Technology, Delft (Netherlands)

    1992-12-31

    The processes in the freeboard of a fluidized bed combustor have an important impact on both the elutriation of fly ash particles and the emission of noxious gases. The main features have been studied for already several decades. In order to understand the phenomena more thoroughly, the details have to be studied. This paper presents the results of measurements of the gas velocity at different locations in the freeboard. Experiments were performed in the pressurized fluidized bed combustor of the Delft University of Technology, The Netherlands, at 8 bar and a freeboard temperature of 850 C. The measuring method used the temperature flucutations naturally present in the combustion process which were recorded by axially displaced thermocouples. By means of mathematical correlation of the recorded signals, the local gas velocity is calculated. The resulting radial velocity profiles of the upper part of the freeboard are very similar to one-phase turbulent pipe flow profiles. Deviations from the expected axial symmetrical velocity profile which were measured at the lowest level are described to the non-axial symmetrical bed behaviour. (orig.) [Deutsch] Die Vorgaenge im Freiraum ueber Wirbelbettverbrennungssysteme spielen eine bedeutende Rolle bei der Entstehung und der Minimierung von festen und gasfoermigen Emissionen. Obwohl in diesem Zusammenhang schon seit langem wesentlichste Kenngroessen des Freiraums Gegenstand von Untersuchungen sind, beduerfen Einzelheiten der Gas- und Partikelstroemung noch weiterhin detaillierter Erfassung. Hierzu werden Daten der Geschwindigkeitsverteilung benoetigt, deren Ermittlung mit konventionellen Messtechniken, insbesondere in Druckwirbelschichtfeuerungen, technisch problematisch ist. In dem Vortrag wird ueber eine Messmethode zur Geschwindigkeitsbestimmung berichtet, bei der feuerungsseitige Temperaturschwankungen ueber in Stroemungsrichtung versetzte Thermoelemente aufgenommen und mathematisch korreliert werden. Diese Methode wurde

  4. H{sub 2}S removal from coal gas at elevated temperature and pressure in fluidized bed with zinc titanate sorbents. 1. Cyclic tests

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, W.; Abbasian, J. [Enviropower Inc., Espoo (Finland)

    1995-05-01

    Simplified integrated gasification combined cycle (IGCC) processes are considered to be among the most efficient and environmentally acceptable technologies for power generation from coal. In such processes the coal is gasified at pressure and the coal gas is cleaned and combusted in a gas turbine. Coal gas cleanup at elevated pressure and temperature in the IGCC processes offers advantages in higher power generation efficiency and simpler plant configuration. Regenerable mixed metal oxide sorbents are the prime candidates for removal of hydrogen sulfide (the main pollutant) from the hot coal gas in the simplified IGCC processes. In this paper, the results of cyclic sulfidation/regeneration tests conducted with two zinc titanate sorbents are presented and discussed. These tests were carried out at high pressure and temperature (20 bar, 550-650{degree}C) in a bench-scale fluidized-bed reactor. The results indicate that the reactivity of both sorbents towards H{sub 2}S gradually decline in cyclic sulfidation/regeneration tests. 20 refs., 11 figs., 4 tabs.

  5. The standard-design gas turbine for use in pressurized fluidized beds; Die Standard-Gasturbine im Druckwirbelschicht-Einsatz

    Energy Technology Data Exchange (ETDEWEB)

    Stuhlmueller, F. [Siemens AG, Erlangen (Germany). Bereich Energieerzeugung (KWU); Schauenburg, G. [Siemens AG, Muelheim an der Ruhr (Germany). Bereich Energieerzeugung (KWU); Waldinger, D. [Siemens AG, Muelheim an der Ruhr (Germany). Bereich Energieerzeugung (KWU)

    1995-12-01

    Gas turbines are designed for operation with high-calorific, clean fuels. If a competent and reliable hot gas cleaning is available, these machines can be operated also with pressurized fluidized beds as combustion chambers. The necessary modifications for a Siemens V64.3 gasturbine are outlined. The capacity data obtainable with a circulating pressurized fluidized bed as well as important data for part-load operation on combustion of hard coal and brown coal are determined. (orig.) [Deutsch] Gasturbinen sind fuer den Betrieb mit hochkalorigen, sauberen Brennstoffen konzipiert. Ist eine wirksame, zuverlaessige Heissgasreinigung verfuegbar, dann koennen diese Maschinen auch mit Druckwirbelschichten als Brennkammern eingesetzt werden. Fuer eine Siemens V64.3-Gasturbine werden die dazu erforderlichen Modifikationen dargestellt und die mit einer zirkulierenden Druckwirbelschicht erreichbaren Leistungswerte sowie der Verlauf wichtiger Daten im Teillastbetrieb fuer Stein- und Braunkohleverbrennung ermittelt. (orig.)

  6. In-bed sulphur capture during pressurized fluidized-bed hydroretorting of Eastern oil shales

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Rue, D.M.; Lau, F.S. (Institute of Gas Technology, Chicago, IL (USA))

    1991-11-01

    The Institute of Gas Technology is developing a pressurized fluidized-bed hydroretorting (PFH) process for the production of oil from Eastern oil shales. The sulphur present in the Eastern oil shales is converted to H{sub 2}S during hydroretorting. A solid sorbent (limestone or siderite) may be added to the PFH reactor with the oil shale to achieve in-bed desulphurization. The effects of operating conditions on the effectiveness of in-bed sulphur capture with limestone and siderite have been investigated. Reactivities of a limestone and a siderite towards H{sub 2}S were determined in experiments conducted in an ambient pressure thermogravimetric analyser. These tests were conducted in the temperature range of 480-565{degree}C using solid sorbents with an average particle diameter of 0.018 cm ({minus}60{plus}100 mesh). The results of thermogravimetric analysis tests indicate that both limestone and siderite should be capable of capturing a significant fraction of H{sub 2}S removal with in-bed sorbents. The results of these tests confirm that a significant fraction of H{sub 2}S produced in the PFH reactor can be removed with in-bed sorbents. 10 refs., 8 figs., 6 tabs.

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

    Science.gov (United States)

    Plackmeyer, J.

    1982-07-01

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

  8. Pressurized Fluidized-Bed Hydroretorting of eastern oil shales. Final report, June 1992--January 1993

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.J.; Mensinger, M.C.; Erekson, E.J.; Rue, D.M.; Lau, F.S. [Institute of Gas Technology, Chicago, IL (United States); Schultz, C.W.; Hatcher, W.E. [Alabama Univ., University, AL (United States). Mineral Resources Inst.; Parekh, B.K. [Kentucky Univ., Lexington, KY (United States). Center for Applied Energy Research; Bonner, W.P. [Tennessee Technological Univ., Cookeville, TN (United States)

    1993-03-01

    The Devonian oil shales of the Eastern United States are a significant domestic energy resource. The overall objective of the multi-year program, initiated in September 1987 by the US Department of Energy was to perform the research necessary to develop the pressurized fluidized-bed hydroretorting (PFH) process for producing oil from Eastern oil shales. The program also incorporates research on technologies in areas such as raw shale preparation, beneficiation, product separation and upgrading, and waste disposal that have the potential of improving the economics and/or environmental acceptability of recovering oil from oil shales using the PFH process. The program was divided into the following active tasks: Task 3 -- Testing of Process Improvement Concepts; Task 4 -- Beneficiation Research; Task 6 -- Environmental Data and Mitigation Analyses; and Task 9 -- Information Required for the National Environmental Policy Act. In order to accomplish all of the program objectives, tho Institute of Gas Technology (ICT), the prime contractor, worked with four other institutions: The University of Alabama/Mineral Resources Institute (MRI), the University of Alabama College of Engineering (UA), University of Kentucky Center for Applied Energy Research (UK-CAER), and Tennessee Technological University (TTU). This report presents the work performed by IGT from June 1, 1992 through January 31, 1993.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-04-01

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

  10. Pressurized fluidized-bed hydroretorting of Eastern oil shales. Annual report, June 1991--May 1992

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.J.; Mensinger, M.C.; Rue, D.M.; Lau, F.S. [Institute of Gas Technology, Chicago, IL (United States); Schultz, C.W. [Alabama Univ., University, AL (United States); Parekh, B.K. [Kentucky Univ., Lexington, KY (United States); Misra, M. [Nevada Univ., Reno, NV (United States); Bonner, W.P. [Tennessee Technological Univ., Cookeville, TN (United States)

    1992-11-01

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

  11. Sulfur removal in advanced two stage pressurized fluidized bed combustion. Technical report, 1 March--31 May 1994

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Chowdiah, P.; Hill, A.H.; Rue, D.M. [Inst. of Gas Technology, Chicago, IL (United States)

    1994-09-01

    The objective of this study is to obtain data on the rates of reaction between hydrogen sulfide (H{sub 2}S) and uncalcined calcium-based sorbents under operating conditions relevant to first stage (carbonizer) of Advanced Two-Stage Pressurized Fluidized-Bed Combustors (PFBC). In these systems the CO{sub 2} partial pressure in the first stage generally exceeds the equilibrium value for calcium carbonate decomposition. Therefore, removal of sulfur compounds takes place through the reaction between H{sub 2}S and calcium carbonate. To achieve this objective, the rates of reaction between hydrogen sulfide and uncalcined calcium-based sorbents will be determined by conducting tests in pressurized thermogravimetric analyzer (TGA) and high-pressure/high-temperature fluidized-bed reactor (HPTR) units. The effects of sorbent type, sorbent particle size, reactor temperature and pressure, and CO{sub 2} and H{sub 2}S partial pressures on the sulfidation reaction rate will be determined. During this quarter a series of sulfidation tests were conducted in the high-pressure/high-temperature fluidized-bed reactor (HPTR) units. The effects of sorbent type, sorbent particle size, reactor temperature and pressure, and CO{sub 2} and H{sub 2}S partial pressures on the sulfidation reaction rate will be determined. During this quarter a series of sulfidation tests were conducted in the high-pressure high-temperature thermogravimetric analyzer (HPTGA unit) using limestone and dolomite. The results suggest that half-calcined dolomite is much more reactive than uncalcined limestone. Also, temperature in the range of 800 to 950 C did not significantly affect the sulfidation reaction rates for both limestone and dolomite.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhen Fan

    2006-05-30

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

  13. Sulfur removal in advanced two stage pressurized fluidized bed combustion. Technical report, December 1, 1994--February 28, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.

    1996-03-01

    The objective of this study is to obtain data on the rates and the extent of sulfation reactions involving partially sulfided calcium-based sorbents, and oxygen as well as sulfur dioxide, at operating conditions closely simulating those prevailing in the second stage (combustor) of Advanced Two-Stage Pressurized Fluidized-Bed Combustors (PFBC). In these systems the CO{sub 2} partial pressure generally exceeds the equilibrium value for calcium carbonate decomposition. Therefore, calcium sulfate is produced through the reactions between SO{sub 2} and calcium carbonate as well as the reaction between calcium sulfide and oxygen. To achieve this objective, the rates of reaction involving SO{sub 2} and oxygen (gaseous reactant); and calcium sulfide and calcium carbonate (solid reactants), will be determined by conducting tests in a pressurized thermogravimetric analyzer (HPTGA) unit. The effects of sorbent type, sorbent particle size, reactor temperature and pressure; and O{sub 2} as well as SO{sub 2} partial pressures on the sulfation reactions rate will be determined. During this quarter, samples of the selected limestone and dolomite, sulfided in the fluidized-bed reactor during last quarter, were analyzed. The extent of sulfidation in these samples was in the range of 20 to 50%, which represent carbonizer discharge material at different operating conditions. The high pressure thermogravimetric analyzer (BPTGA) unit has been modified and a new pressure control system was installed to eliminate pressure fluctuation during the sulfation tests.

  14. Sulfur removal in advanced two-staged pressurized fluidized-bed combustion; [Quarterly] report, September 1--November 1993

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Hill, A.H.; Wangerow, J.R.; Rue, D.M.

    1994-03-01

    The objective of this study is to obtain data on the rates of reaction between hydrogen sulfide (H{sub 2}S) and uncalcined calcium-based sorbents under operating conditions relevant to first stage (carbonizer) of Advanced Two-Stage Pressurized Fluidized-Bed Combustors (PFBC). In these systems the CO{sub 2} partial pressure in the first stage generally exceeds the equilibrium value for calcium carbonate decomposition. Therefore, removal of sulfur compounds takes place through the reaction between H{sub 2}S and calcium carbonate. To achieve this objective, the rates of reaction between hydrogen sulfide and uncalcined calcium-based sorbents will be determined by conducting tests in pressurized thermogravimetric analyzer (TGA) and high-pressure/high-temperature fluidized-bed reactor (HPTR) units. The effects of sorbent type, sorbent particle size, reactor temperature and pressure, and CO{sub 2} and H{sub 2}S partial pressures on the sulfidation reaction rate will be determined. A pressurized TGA unit has been purchased by IGT for use in this project.

  15. Sulfur removal in advanced two stage pressurized fluidized bed combustion. Technical report, September 1--November 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Hill, A.; Wangerow, J.R. [Inst. of Gas Technology, Chicago, IL (United States)

    1994-12-31

    The objective of this study is to obtain data on the rates and the extent of sulfation reactions involving partially sulfided calcium-based sorbents, and oxygen as well as sulfur dioxide, at operating conditions closely simulating those prevailing in the second stage (combustor) of Advanced Two-Stage Pressurized Fluidized-Bed Combustors (PFBC). In these systems the CO{sub 2} partial pressure generally exceeds the equilibrium value for calcium carbonate decomposition. Therefore, calcium sulfate is produced through the reactions between SO{sub 2} and calcium carbonate as well as the reaction between calcium sulfide and oxygen. To achieve this objective, the rates of reaction involving SO{sub 2} and oxygen (gaseous reactant); and calcium sulfide and calcium carbonate (solid reactants), will be determined by conducting tests in a pressurized thermogravimetric analyzer (HPTGA) unit. The effects of sorbent type, sorbent particle size, reactor temperature and pressure; and O{sub 2} as well as SO{sub 2} partial pressures on the sulfation reactions rate will be determined. During this quarter, samples of the selected limestone and dolomite were sulfided in the fluidized-bed reactor. These tests were conducted in both calcining and non-calcining operating conditions to produce partially-sulfided sorbents containing calcium oxide and calcium carbonate, respectively. These samples which represent the carbonizer discharge material, will be used as the feed material in the sulfation tests to be conducted in the HPTGA unit during the next quarter.

  16. Heat and Mass Transfer Enforcement of Vibrating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    ChuZhide; YangJunhong; 等

    1994-01-01

    This paper briefly introduces the development of vibrating fluidized bed at home and abroad,elaborates the vibration properties of vibrating fluidized bed.the fluidizing velocity and pressure drop of the bed layer,it also deduces the non-steady state drying dynamic equations of vibrating fluidized bed,analyzes main factors which influence the drying rate and inquires into drying rules of fixed bed and vibrating fluidized bed.

  17. Identification of defluidization region in a gas-solid fluidized bed using a method based on pressure fluctuation measurements

    Directory of Open Access Journals (Sweden)

    M. R. Parise

    2009-09-01

    Full Text Available Industrial applications that involve fluidized bed operations must prevent the undesirable phenomenon of partial or complete bed defluidization. Defluidization can be avoided by increasing the gas velocity and/or, in some cases, changing the solid feed conditions in the system, provided that the changes in the hydrodynamics of the flow are detected early enough. The use of a technique that can perform an early detection of the defluidization condition in industrial applications is important, in order to avoid the loss of efficiency or even an undesirable shutting down of the process. The objective of this work is to show the application of a method for early detection of the condition where the bed is tending to the defluidization, in a gas-solid fluidized bed flow. The method is based on pressure fluctuation measurements. Experimental tests are carried out using two solid particles: microcrystalline cellulose and sand. Results show that the proposed method is efficient in detecting the fluidization condition in a conventional bubbling bed regime. The potential of application of the technique is also shown for the control of the defluidization phenomenon in industry.

  18. Parametric evaluation of an electrostatic precipitator at simulated Pressurized Fluidized Bed Combustion (PFBC) conditions. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rugg, D.E.; Rinard, G.A.; Durham, M.D.; Armstrong, J.A.

    1985-08-01

    The final results of a bench scale test program of an ESP operating at PFBC conditions are presented. The results include an evaluation of the performance of an ESP for three different electrodes at several corona power levels. In order to determine the optimum corona electrode for these tests, a series of electrode evaluation tests were performed. These tests were performed on three different corona electrodes operating at different power levels at a temperature of 900C (1650F), a pressure of 1 MPa (10 atm), and a gas velocity of 0.76 m/s (2.5 ft/s). Following the electrode evaluation tests, final parametric evaluations were made on the ESP utilizing the optimum electrode design. These parametric evaluations were performed for temperatures of 843C (1550F) and 900C (1650F), pressures of 640 kPa (6.4 atm) and 1 MPa (10 atm), velocities of 0.76 m/s (2.5 ft/s) and 1.37 m/s (4.5 ft/s), electrode voltages of 85 kV and 115 kV, and corona currents of 5 mA and 10 mA. The results of the electrode evaluation and parametric tests are given. In all cases, for a given electrode, the highest performance was obtained with the highest operating voltage. The test results indicated that the scalloped electrode provided the highest collection efficiency and lowest power consumption. Furthermore, hot gas cleanup by use of an ESP at 900C (1650F) and 1 MPa (10 atm) is shown to be technically and economically feasible. 3 refs., 27 figs., 39 tabs.

  19. Theoretical investigations of the operating characteristics of circulating pressurized fluidized bed combustors; Theoretische Untersuchungen zum Betriebsverhalten zirkulierender Druckwirbelschichtfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, M.; Krumm, W.

    1999-07-01

    The combination of gas turbine and water-/steam cycle is a proper alternative to increase the efficiency of power plants. Coal fired power plants can be designed as reactors with pressurized coal gasification, pressurized coal dust combustion or a pressurized fluidized bed combustion to realize these plant design. Mathematical modeling and simulation are used to support the development of new power plant concepts, e.g. pressurized fluidized bed combustion. In this paper a one-dimensional model for a pressurized fluidized circulating bed combustion power plant is presented. The modeling structure allows to vary different parameters to identify the particular influence on the overall plant behavior. The model is enlarged by a more detailed balance for limestone. After describing the theoretical background of the influence of added limestone rate on the emissions of sulfurdioxide is shown. (orig.) [German] Ausgehend vom Prinzip eines Dampfkraftwerks mit atmosphaerischer Wirbelschichtfeuerung werden der Dampf- und Gasturbinenprozess bei den druckaufgeladenen Konzepten quasi parallel betrieben und die Gasturbine mit dem Rauchgas aus der Kohlenfeuerung beaufschlagt. Die wesentlichen Unterschiede zu erdgas- oder oelbefeuerten Kombianlagen sind bei den Druckwirbelschichtkonzepten, durch den in Zusammensetzung und Feuchtegehalt stark variierenden Brennstoff Kohle und durch die Auskopplung grosser Waermemengen bei der integrierten Dampferzeugung, gegeben. Der Hauptanteil der erzeugten elektrischen Leistung entfaellt auf den Dampfturbinenprozess. Druckwirbelschichtanlagen mit blasenbildender Wirbelschicht sind seit Anfang der 90er Jahre in Betrieb. Entsprechend der Entwicklung bei der atmopshaerischen Wirbelschichtfeuerung zeichnet sich als naechste Generation dieses Kraftwerkstyps die zirkulierende Druckwirbelschicht mit Heissgasfilter ab. Die mathematische Modellbildung hat sich zu einem anerkannten Werkzeug zur Unterstuetzung der Auslegung und der Untersuchung der Wirkung

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    1987-07-31

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

  1. Fluidized bed calciner apparatus

    Science.gov (United States)

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

    1988-01-01

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

  2. Radioactive demonstration of final mineralized waste forms for Hanford waste treatment plant secondary waste (WTP-SW) by fluidized bed steam reforming (FBSR) using the bench scale reformer platform

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Cozzi, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Daniel, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jantzen, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Missimer, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-08-01

    The U.S. Department of Energy’s Office of River Protection (ORP) is responsible for the retrieval, treatment, immobilization, and disposal of Hanford’s tank waste. Currently there are approximately 56 million gallons of highly radioactive mixed wastes awaiting treatment. A key aspect of the River Protection Project (RPP) cleanup mission is to construct and operate the Waste Treatment and Immobilization Plant (WTP). The WTP will separate the tank waste into high-level and low-activity waste (LAW) fractions, both of which will subsequently be vitrified. The projected throughput capacity of the WTP LAW Vitrification Facility is insufficient to complete the RPP mission in the time frame required by the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement (TPA), i.e. December 31, 2047. Therefore, Supplemental Treatment is required both to meet the TPA treatment requirements as well as to more cost effectively complete the tank waste treatment mission. In addition, the WTP LAW vitrification facility off-gas condensate known as WTP Secondary Waste (WTP-SW) will be generated and enriched in volatile components such as 137Cs, 129I, 99Tc, Cl, F, and SO4 that volatilize at the vitrification temperature of 1150°C in the absence of a continuous cold cap (that could minimize volatilization). The current waste disposal path for the WTP-SW is to process it through the Effluent Treatment Facility (ETF). Fluidized Bed Steam Reforming (FBSR) is being considered for immobilization of the ETF concentrate that would be generated by processing the WTP-SW. The focus of this current report is the WTP-SW.

  3. Recurrence analysis of pressure fluctuation in fluidized bed%流化床压力脉动的递归分析

    Institute of Scientific and Technical Information of China (English)

    周云龙; 王芳

    2014-01-01

    在自行搭建的冷态流化床实验台的基础上,采集了风帽入、出口处的压力脉动信号,通过对比、分析不同压力测点的压力信号递归图,来观察流化床内流化特性的差异。改变空气流量,借助递归率RR、确定性DET、递归熵ENTR ,最长对角线Lmax、层状度LAM、竖直或水平线段长度均值TT 等参数来定量分析鼓泡床、节涌床、湍流床和快速流化床4种流型的动力学特性。结果表明:递归定量分析能够有帮助于理解流化床的流动机理,对气固二相流的流型识别具有一定意义。%On the basis of the self-designed fluidized bed , the pressure fluctuation signals were collected at the entrance and exit of the hood in fluidized bed .By contrasting and analyzing the recurrence plots of pressure signals at different test points, the different characteristics of the flows in the fluidized bed could be observed based on RR, DET, ENTR, Lmax, LAM, TT and other parameters to analyze the bubbling regime , slugging regime, turbulent regime and fast fluidized regime in fluidized bed quantitatively as changing the air flow .The results reveal that the recurrence quantification analysis can be well used to help understanding the flow mechanism of fluidized bed , which has great significance for flow regime identification in gas-solid two-phase flow .

  4. Limestone fragmentation and attrition during fluidized bed oxyfiring

    Energy Technology Data Exchange (ETDEWEB)

    Fabrizio Scala; Piero Salatino [Istituto di Ricerche sulla Combustione - CNR, Napoli (Italy)

    2010-04-15

    Attrition/fragmentation of limestone under simulated fluidized bed oxyfiring conditions was investigated by means of an experimental protocol that had been previously developed for characterization of attrition/fragmentation of sorbents in air-blown atmospheric fluidized bed combustors. The protocol was based on the use of different and mutually complementary techniques. The extent and pattern of attrition by surface wear in the dense phase of a fluidized bed were assessed in experiments carried out with a bench scale fluidized bed combustor under simulated oxyfiring conditions. Sorbent samples generated during simulated oxyfiring tests were further characterized from the standpoint of fragmentation upon high velocity impact by means of a purposely designed particle impactor. Results showed that under calcination-hindered conditions attrition and fragmentation patterns are much different from those occurring under air-blown atmospheric combustion conditions. Noteworthy, attrition/fragmentation enhanced particle sulfation by continuously regenerating the exposed particle surface. 13 refs., 8 figs.

  5. Studies of Alkali Sorption Kinetics for Pressurized Fluidized Bed Combustion by High Pressure Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, K.J.; Willenborg, W.; Fricke, C.; Prikhodovsky, A.; Hilpert, K.; Singheiser, L.

    2002-09-20

    This work describes the first approach to use High Pressure Mass Spectrometry (HPMS) for the quantification and analysis of alkali species in a gas stream downstream a sorbent bed of different tested alumosilicates.

  6. Pressurized fluidized-bed power stations. Combined cycle power plants with fluidized-bed combustion, with particular regard to emissions; Druckwirbelschicht-Kraftwerke. Kombikraftwerke mit Druckwirbelschichtfeuerung - Entwicklung fuer Braunkohle unter besonderer Beruecksichtigung des Emissionsverhaltens

    Energy Technology Data Exchange (ETDEWEB)

    Chalupnik, R.W.

    1999-07-01

    Investigations were carried out to find whether this technology is suited for lignite. The state of the art of the pressurized fluidized bed technology for coal is presented. The planning of the experimental programme is explained, including unresolved problems of thermal calculation, raw lignite transport characteristics, and emissions. Emissions of atmospheric and pressurized fluidized bed combustion of coal and lignite are compared, and the results of a theoretical investigation of the potential performance are presented. Recommendations are made for further studies, and an outlook is given to future 'second generation' concepts with higher efficiencies resulting from higher gas turbine inlet temperatures. [German] Die vorliegende Arbeit berichtet ueber die Entwicklung der Kombikraftwerkstechnik mit Druckwirbelschichttechnik. Nachdem die bisherigen Aktivitaeten weltweit fast ausschliesslich fuer den Einsatz von Steinkohle betrieben wurden, bestand die Aufgabenstellung in der Erarbeitung von ersten grundlegenden Ergebnissen, aufgrund derer zu beurteilen war, ob die Druckwirbelschichttechnik fuer den Einsatz von Braunkohle geeignet ist. Kapitel 2 stellt den Stand der Technik der Druckwirbelschichtverbrennung fuer Steinkohle dar. In Kapitel 3 wird die Planung des Versuchsprogramms erlaeutert, die sich an den offenen Fragestellungen zu den waermetechnischen Rechnungen, zum Foerderverhalten von Rohbraunkohle und zum Emissionsverhalten orientierte. In der Diskussion der Ergebnisse in Kapitel 4 erfolgt eine Einordnung und Bewertung der ermittelten Emissionswerte im Vergleich zur Wirbelschichtverbrennung unter atmosphaerischen und druckaufgeladenen Bedingungen von Stein- und Braunkohle. In Kapitel 5 schliesslich werden die Ergebnisse einer durchgefuehrten theoretischen Untersuchung zur Ermittlung des Wirkungsgradpotentials dargestellt. Ferner werden Empfehlungen fuer ergaenzende, weiterfuehrende Untersuchungen gegeben. Fuer die langfristige potentielle

  7. Sulfur removal in advanced two stage pressurized fluidized bed combustion. Technical report, March 1--May 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.

    1995-12-31

    The objective of this study is to obtain data on the rates and the extent of sulfation reactions involving partially sulfided calcium-based sorbents, and oxygen as well as sulfur dioxide, at operating conditions closely simulating those prevailing in the second stage (combustor) of Advanced Two-Stage Pressurized Fluidized-Bed Combustors. In these systems the CO{sub 2} partial pressure generally exceeds the equilibrium value for calcium carbonate decomposition. Therefore, calcium sulfate is produced through the reactions between SO{sub 2} and calcium carbonate as well as the reaction between calcium sulfide and oxygen. To achieve this objective, the rates of reaction involving SO{sub 2} and oxygen, calcium sulfide and calcium carbonate will be determined by conducting tests in a pressurized thermogravimetric analyzer unit. The sulfate tests conducted during this quarter, focused on the determination of the rate of sulfation reaction involving partially sulfided half-calcined dolomite and oxygen. The test parameters included CO{sub 2} and O{sub 2} concentrations, reaction temperature and pressure, as well as the sorbent particle size. The results obtained during this quarter suggest that the rate of sulfation reaction involving partially sulfided half-calcined dolomite and oxygen is very fast at temperatures above 850 C which rapidly increases with increasing temperature, achieving more than 85% conversion in less than a few minutes. The reaction appears to continue to completion, however, above 85% conversion, the rate of reaction appears to be low, requiring long residence time to reach complete conversion.

  8. The formation of impurities in fluidized-bed gasification of biomass, peat and coal; Epaepuhtauksien muodostuminen leijukerroskaasutuksessa

    Energy Technology Data Exchange (ETDEWEB)

    Kurkela, E.; Laatikainen-Luntama, J.; Kurkela, M.; Leppaelahti, J.; Koljonen, T.; Oesch, P. [VTT Energy, Espoo (Finland); Alen, R. [Jyvaeskylae Univ. (Finland)

    1996-12-01

    The objective of this three-year-long project was to study the effects of different process parameters and bed materials on the formation of impurities in pressurized fluidized-bed gasification. The main emphasis of the project was focused on the formation of tars and nitrogen compounds in wood, peat and coal gasification. The aims of the research were to find out such operating conditions, where the formation of problematic high-molecular-weight tars can be minimised and to create a better understanding on the fate of fuel nitrogen in fluidized-bed gasifiers. Main part of the research was carried out in a bench-scale pressurised fluidized-bed reactor (ID 30 mm), where the effects of pressure, temperature, gas atmosphere and bed material were studied with different feedstocks. Most of the test series were carried out using the same feedstocks as earlier used in the PDU-scale fluidized-bed gasification tests of VTT (pine wood, pine bark, wheat straw, two peats, Rhenish brown coal, Polish and Illinois No.6 bituminous coals). The effects of operating parameters on the product yields (gas components, tars, char) were first studied under inert nitrogen atmosphere. The conversion of fuel nitrogen into ammonia and HCN were also determined for the different feedstocks over the different operating conditions. These studies showed that ammonia is the main fixed nitrogen compound of fluidized-bed pyrolysis with all the feedstocks studied. The conversions of fuel nitrogen into ammonia and HCN was highest with the high volatile fuels and lowest with the two hard coals. Gas atmosphere had a dramatic effect on the conversion of fuel nitrogen; much higher ammonia yields were determined in real gasification gas atmosphere than in inert pyrolysis carried out in N{sub 2} or Argon atmosphere. In addition to the pressurised fluidized-bed pyrolysis tests, laboratory scale pyrolysis research was carried out in order to compare the pyrolysis behaviour of the different feedstocks

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

    Science.gov (United States)

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

    2016-01-04

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

  10. MULTISTAGE FLUIDIZED BED REACTOR

    Science.gov (United States)

    Jonke, A.A.; Graae, J.E.A.; Levitz, N.M.

    1959-11-01

    A multistage fluidized bed reactor is described in which each of a number of stages is arranged with respect to an associated baffle so that a fluidizing gas flows upward and a granular solid downward through the stages and baffles, whereas the granular solid stopsflowing downward when the flow of fluidizing gas is shut off.

  11. Fluidization quality analyzer for fluidized beds

    Science.gov (United States)

    Daw, C. Stuart; Hawk, James A.

    1995-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-11-24

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

  13. DEVELOPMENT OF PRESSURIZED CIRCULATIONG FLUIDIZED BED PARTIAL GASIFICATION MODULE(PGM)

    Energy Technology Data Exchange (ETDEWEB)

    Archie Robertson

    2003-04-17

    Foster Wheeler Power Group, Inc. is working under US Department of Energy 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% and produce 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 amount of syngas and char produced by the PGM can be tailored to fit the production objectives of the overall plant, i.e., power generation, clean liquid fuel production, chemicals production, etc. Hence, PGM is a robust building block that offers all the advantages of coal gasification but in a more user-friendly form; it is also fuel flexible in that it can use alternative fuels such as biomass, sewerage sludge, etc. This report describes the work performed during the January 1--March 31, 2003 time period.

  14. Biparticle fluidized bed reactor

    Science.gov (United States)

    Scott, C.D.

    1993-12-14

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

  15. Fluidized bed coal combustion reactor

    Science.gov (United States)

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

    1981-01-01

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

  16. 气固搅拌流化床中压力脉动特性%Pressure fluctuation in gas-solid agitated fluidized bed

    Institute of Scientific and Technical Information of China (English)

    张永俊; 王嘉骏; 顾雪萍; 冯连芳

    2016-01-01

    气固搅拌流化床反应器可用于黏结性聚合物颗粒的流态化过程,流化床中通气湍动与搅拌的相互作用关系仍不明确。通过压力脉动的统计分析、功率谱分析和小波分析,考察了搅拌桨型式和搅拌转速对流态化特性的影响规律。实验发现,搅拌转速和搅拌桨型式对床层压力影响较小,但对压力脉动影响显著。搅拌流化床中搅拌与通气湍动对流态化共同作用,双层锚式桨、框式桨等小桨叶面积的搅拌桨在较高转速条件下能强化流态化过程,与普通流化床相比具有更小的气泡尺寸和压力脉动,搅拌可抑制气泡聚并、破碎气泡,维持床层均匀流态化;而新型具有大桨叶面积的自清洁桨的搅拌作用强烈,在较高的转速下易形成桨叶前方的颗粒堆积和桨叶后方的气体短路等非正常流化现象,适宜于中等转速的操作条件。%Gas-solid agitated fluidized beds can be used to improve the fluidization performance of sticky polymer particles. Experimental pressure fluctuation signals were analyzed with statistics analysis, power spectrum analysis and wavelet analysis for investigating the influence of agitation speeds and types of agitators on the fluidization characteristic. Due to the effects of suppression and breakage on bubbles caused by agitation, lower pressure fluctuation amplitude and smaller bubbles were found in the agitated fluidized bed compared to general fluidized bed. The synergy between gas flow and agitation occurred in the agitated fluidized bed. For a gas-solid fluidized bed with an anchor impeller or a frame impeller, sufficiently high agitation speed was needed to improve fluidization performance. However, for self-cleaning agitator, higher agitation speed engendered adverse phenomena of gas short circuit and particles accumulation near the blades. Therefore, the feasible agitation speed was recommended for extending the application of the

  17. Desulfurization of hot coal gas in fluidized bed with regenerable zinc titanate sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, W.; Salo, K.; Abbasian, J. (Enviropower Inc., Espoo (Finland))

    1994-01-01

    Integrated gasification combined cycle (IGCC) power generation processes are considered to be among the most attractive technologies for the 21st century. In such processes, solid fuels such as coal are gasified at pressure and the fuel gas is cleaned and combusted in the gas turbine. The gas cleanup is necessary not only for the protection of the gas turbine hardware, but also to comply with environmental regulations. In the so-called 'simplified' IGCC process, the fuel gas is cleaned at high temperature and pressure to improve the overall cycle efficiency. The hot gas cleanup system includes a high-temperature, high-pressure desulfurization unit and particulate removal system. The former comprises two fluidized bed reactors utilizing regenerable zinc titanate sorbents capable of removing the sulfur gases (primarily H[sub 2]S) to below 50 ppmv. The latter employs rigid ceramic filter elements operating at up to 700[degree]C and 20 bar and is capable of reducing the 'fines' concentration to an acceptable level for a gas turbine. Novel regenerable zinc titanate sorbents suitable for fluidized-bed application have been tested. The sulfur capture and attrition characteristics of these sorbents have been evaluated in extensive testing in a bench-scale fluidized-bed reactor operating at high pressure and temperature conditions expected in IGCC operation. Two different gas mixtures representing air-blown gasifier exit gas with and without in-situ desulfurization with Ca-based sorbents have been used. H[sub 2]S removal efficiencies of higher than 99% at acceptable levels of sorbent conversion have been achieved in all these experiments with minimal sorbent deterioration. 4 refs., 7 figs., 1 tab.

  18. SIMULATION OF PARTICLE COATING IN THE SUPERCRITICAL FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Carsten; Vogt; Ernst-Ulrich; Hartge; Joachim; Werther; Gerd; Brunner

    2005-01-01

    Fluidized bed technology using supercritical carbon dioxide both as a fluidizing gas and as a solvent for the coating material makes possible the production of thin, uniform and solvent-free coatings. But operation at low fluidizing velocities, which is favorable to facilitate gas cleaning under the high pressure conditions, may lead to uneven distribution of the coating in the fluidized bed and to unstable operation due to agglomeration. Therefore a model has been developed which describes local fluid dynamics within the high pressure fluidized bed. Based on this model, the coating process is described and the distribution of the coating inside the fluidized bed is calculated. Furthermore a submodel for the calculation of local concentrations of liquid paraffin has been set up, which may be used as a basis for the prediction of agglomeration and thus stability of operation.

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    1987-09-15

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

  20. Pressurized fluidized-bed hydroretorting of eastern oil shales. Volume 2, Task 3, Testing of process improvement concepts: Final report, September 1987--May 1991

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    This final report, Volume 2, on ``Process Improvement Concepts`` presents the results of work conducted by the Institute of Gas Technology (IGT), the Illinois Institute of Technology (IIT), and the Ohio State University (OSU) to develop three novel approaches for desulfurization that have shown good potential with coal and could be cost-effective for oil shales. These are (1) In-Bed Sulfur Capture using different sorbents (IGT), (2) Electrostatic Desulfurization (IIT), and (3) Microbial Desulfurization and Denitrification (OSU and IGT). Results of work on electroseparation of shale oil and fines conducted by IIT is included in this report, as well as work conducted by IGT to evaluate the restricted pipe discharge system. The work was conducted as part of the overall program on ``Pressurized Fluidized-Bed Hydroretorting of Eastern Oil Shales.``

  1. Cluster Dynamics in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-11-01

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

  2. Single-stage fluidized-bed gasification

    Science.gov (United States)

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

    1982-04-01

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

  3. Dual Fluidized Bed Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-09-30

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

  4. H{sub 2}S removal from coal gas at elevated temperature and pressure in fluidized bed with zinc titanate sorbents. 2. Sorbent durability

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, W.; Abbasian, J. [Enviropower Inc., Espoo (Finland)

    1995-09-01

    High-temperature high-pressure sulfur removal is considered as one of the key steps of the hot gas cleanup train of an IGCC process. Coal-derived gasifier gas contains sulfur gases (mainly H{sub 2}S) which are converted to SO{sub 2} when the gas is combusted in the gas turbine. Cyclic sulfidation/regeneration tests were carried out in a pressurized fluidized bed reactor to remove H{sub 2}S from a simulated coal gas to below 100 ppmv, using regenerable zinc titanate sorbents. The results, which were reported in part 1 of this paper, showed that the sorbent reactivity deteriorates in the cyclic process. In part 2, physical, chemical, and structural changes which the sorbents undergo in the cyclic tests are reported and discussed. The results of analyses conducted with fresh and used sorbents indicate that the loss of reactivity and sorbent deterioration is probably due to zinc migration to the surface of the sorbent particle during the high-temperature high-pressure cyclic process. 13 refs., 11 figs., 2 tabs.

  5. Investigations into the effects of the hybrid concepts on the performance of a pressurized fluidized bed combustion system; Untersuchungen zum Einfluss des Hybridkonzeptes auf den Betrieb einer Druckwirbelschichtfeuerung

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

    Pressurized fluidized bed combustion has particular advantages as compared to conventional firing systems e.g. in-situ pollutant removal, high thermal efficiencies even in intermediate power ranges, and small reactor sizes. The widespread use of PFBC depends on rising the gasturbine inlet temperature in order to increase efficiencies. In a staged combustion process, which is a kind of a hybrid system, coal is burned substoichometrically in a pressuried fluidized bed producing a low calorific value gas. After hot gas cleanup (<700 C) the gas is afterburned allowing for gasturbine inlet temperatures of more than 1 200 C. At the IVD-PFBC test facility experiments were carried out with regard to composition of the produced gas, carbon-conversion and sulphur capture at various temperatures, pressures and air ratios. The results were compared to chemical equilibrium calculations. Based on experimental data the increase of thermal efficiency through staged combustion was studied using a process simulation program. In comparison with a standard combined cycle with a lignite fired PFBC, staged combustion led to an increase in thermal efficiency of up to 4,5% at equivalent operation conditions (thermal capacity, steam quality). (orig.) [Deutsch] Druckwirbelschichtfeuerungen (DWSF) weisen gegenueber konventionellen Feuerungen einige Vorteile auf wie z.B. in situ Schadstoffminderung, hohe thermische Wirkungsgrade auch im mittleren Leistungsbereich und geringes Bauvolumen. Die weitere Verbreitung der DWSF wird jedoch massgeblich davon abhaengen, inwieweit sich durch Erhoehung der Gasturbinen-Eintrittstemperatur ein weiteres Wirkungsgradpotential erschliessen laesst. Bei der gestuften Verbrennung, einem sog. Hybridprozess, wird Kohle in der Wirbelbrennkammer teiloxidiert. Das entstehende Schwachgas wird anschliessend gereinigt und in einer Nachbrennkammer vollstaendig umgesetzt, so dass Gasturbinen-Eintrittstemperaturen ueber 1 200 C erreicht werden koennen. An der IVD

  6. The effect of working parameters and the properties of coal on emission in pressurized fluidized bed combustion; Der Einfluss von Betriebsparametern und Kohleeigenschaften auf die Emissionen bei der Druckwirbelschichtfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, M.; Bonn, B.; Baumann, H.

    1993-12-31

    The aim of a research project at the Deutsche Monta Technologie-Research and Testing Company (DMT-FP) is, among others, to determine the effects of working conditions on the emission of harmful substances of a pressurized fluidized bed combustion by experimental investigations. The investigations described here were carried out on a stationary pressurized fluidized bed reactor on the technical scale. A first comparison of the results achieved in this reactor with those on a pressurized fluidized bed pilot plant show that the level of emission differs only slightly, taking into account the somewhat different combustion conditions. (orig./IHL) [Deutsch] Das Ziel eines Forschungsprojektes bei der Deutschen Monta Technologie - Gesellschaft fuer Forschung und Pruefung mbH (DMT-FP), ist unter anderem, durch experimentelle Untersuchungen die Wirkungen von Betriebsbedingungen auf die Schadstoffemissionen einer Druckwirbelschichtfeuerung zu ermitteln. Die im folgenden beschriebenen Untersuchungen wurden in einem stationaeren Druckwirbelschichtreaktor im Technikums-Massstab durchgefuehrt. Ein erster Vergleich der in diesem Reaktor erzielten Ergebnisse mit denen einer Druckwirbelschicht-Pilotanlage zeigte, dass die Hoehe der Emissionen - unter Beruecksichtigung der etwas unterschiedlichen Feuerungsbedingungen - nur wenig voneinander abwichen. (orig./IHL)

  7. Air Distributor Designs for Fluidized Bed Combustors: A Review

    Directory of Open Access Journals (Sweden)

    A. Shukrie

    2016-06-01

    Full Text Available Fluidized bed combustion (FBC has been recognized as one of the suitable technologies for converting a wide variety of biomass fuels into energy. One of the key factors affecting the successful operation of fluidized bed combustion is its distributor plate design. Therefore, the main purpose of this article is to provide a critical overview of the published studies that are relevant to the characteristics of different fluidized bed air distributor designs. The review of available works display that the type of distributor design significantly affects the operation of the fluidized bed i.e., performance characteristics, fluidization quality, air flow dynamics, solid pattern and mixing caused by the direction of air flow through the distributors. Overall it is observed that high pressure drop across the distributor is one of the major draw backs of the current distributor designs. However, fluidization was stable in a fluidized bed operated at a low perforation ratio distributor due to the pressure drop across the distributor, adequate to provide uniform gas distribution. The swirling motion produced by the inclined injection of gas promotes lateral dispersion and significantly improves fluidization quality. Lastly, the research gaps are highlighted for future improvement consideration on the development of efficient distributor designs.

  8. Investigation of dynamic load changes of a combined cycle power plant with circulating pressurized fluidized bed using a simulation model; Untersuchungen zum dynamischen Lastaenderungsverhalten eines Kombi-Kraftwerks mit zirkulierender Druckwirbelschicht mit Hilfe eines Simulationsmodells

    Energy Technology Data Exchange (ETDEWEB)

    Bockamp, S.; Krumm, W.

    2001-07-01

    Fluidized bed combustion technology offers high efficient power plants with low emissions using coal, biomass or waste as fuel input. Mathematical models support the optimisation and design of power plants. The mathematical fluidized bed system model developed at the Institut fuer Energietechnik, Universitaet Siegen, allows the simulation of steady state or dynamic process operation behaviour. This model is used for detailed examining of the overall combined cycle power plant and the interactions between the single components gas turbine, furnace and water-/steam cycle. The described simulation model presented in this paper is applied for the determination of the transient operation behaviour of a combined cycle power plant based on pressurized circulating fluidized bed combustion. The effects of a step function load change on the temperature profile, the emissions and on process reaction of water/steam cycle and on gas turbine is analysed and discussed in detail at different component outlets. (orig.) [German] Das Kombi-Kraftwerk mit zirkulierender Druckwirbelschichtfeuerung stellt ein effizientes und emissionsarmes Konzept dar. Neben den wirbelschichtinhaerenten Eigenschaften wie geringerer Schadstoffbildung durch niedrige Feuerraumtemperaturen und der integrierten Schadstoffreduktion durch die Zugabe von Zuschlagstoffen verspricht die druckaufgeladenen Variante aufgrund der hohen Querschnittsbelastung eine kompakte Bauart sowie einen fuer die Verstromung von Kohlen hohen Wirkungsgrad. Kohle kann mit diesem Verfahren direkt innerhalb eines Gasturbinenprozesses genutzt werden. Mit Hilfe der mathematischen Modellbildung koennen die dynamischen Auswirkungen auf das Gesamtsystem Kombi-Kraftwerk untersucht werden. (orig.)

  9. PREDICTION OF FLOW REGIMES IN SPOUT-FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    Jiyu Zhang; Fengxiang Tang

    2006-01-01

    Five main flow regimes in spout-fluidized bed were identified in this study, namely, fixed bed, spout with aeration, spout-fluidization, jet in fluidized bed and slugging, together with their corresponding major frequencies translated from pressure signals. The empirical equation A=aBb, in which A=Fr* /(H/Di) and B=(Fr*/(H/D))/(μg/μmf) are respectively the spout-geometry and spout-geometry-fluidization dimensionless numbers, was proposed to distinguish these flow regimes.

  10. Fluidized bed combustion: mixing and pollutant limitation

    Energy Technology Data Exchange (ETDEWEB)

    Leckner, B. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Energy Conversion

    1997-10-01

    Fluidized bed combustion (FBC) has been applied commercially during a few decades, and sufficient knowledge is gained to design boilers with sizes of up to several hundreds of megawatt thermal power (MW{sub th}). The knowledge of what goes on inside a large combustion chamber is still limited, however, and this impedes further optimization and efficient solution of problems that might occur. Despite this lack of knowledge the present survey deals with combustion chamber processes and discusses mixing and distribution of fuel and air in the combustion chamber and its importance for sulphur capture and reduction of emissions of nitrogen oxides. It is desirable to present the material in a general way and to cover the entire field of FBC. However, the scarce openly published information deals mostly with coal combustion in atmospheric circulating fluidized bed (CFB) combustors, and therefore this application will receive most attention, but reference is also made to pressurized combustion and to other fuels than coal. In this context the important work made in the LIEKKI project on the analysis of different fuels and on the influence of pressure should be especially pointed out. (orig.)

  11. Research of fluidized bed cement clinker sintering system by pilot plant; Ryudosho cement shosei gijutsu no kaihatsu. 7

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, T. [Center for Coal Utilization, Japan, Tokyo (Japan); Sato, N.; Hashimoto, I.; Nakatsuka, M. [The Cement Association of Japan, Tokyo (Japan)

    1996-09-01

    While a cement manufacturing process generally performs sintering by using a rotary kiln, a development work has been carried out as a subsidy operation of the Agency of Natural Resources and Energy on a cement sintering technology using a fluidized bed consisted of two furnaces: a jet flow bed granulating furnace and a fluidized bed sintering furnace. This paper reports the results of tests and researches performed during fiscal 1995. A plant with a scale of 20 ton-a-day production started in 1993 after having gone through bench scale tests. The year 1995 conducted by August its performance evaluation, review of the operation method and the safety criteria, and generalization of the tests. A multi-stage cyclone system has been employed in the preheating equipment for cement material powder. A number of improvements have been realized in the aspects of construction and operation, such as stabilization of dust collecting efficiency by employing a high-efficiency type cyclone, and operation with reduced pressure variation. Based on these results, a construction had been progressed in parallel on a new plant upscaled to 200 ton-a-day production. The new plant was completed in December, 1995. 9 figs., 8 tabs.

  12. Agglomeration-Free Distributor for Fluidized Beds

    Science.gov (United States)

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

    1986-01-01

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

  13. Single-particle behaviour in circulating fluidized beds

    DEFF Research Database (Denmark)

    Weinell, Claus Erik; Dam-Johansen, Kim; Johnsson, Jan Erik

    1997-01-01

    This paper describes an experimental investigation of single-particle behaviour in a cold pilot-scale model of a circulating fluidized bed combustor (CFBC). In the system, sand is recirculated by means of air. Pressure measurements along the riser are used to determine the suspension density...

  14. Catalytic decomposition of ammonia in fuel gas produced in pilot-scale pressurized fluidized-bed gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, W.; Ylitalo, M.; Maunula, T.; Abbasian, J. [Enviropower Inc., Tampere (Finland)

    1995-12-01

    Integrated Gasification Combined Cycle (IGCC) process, incorporating pressurized gasification of solid fuels (coal, peat, biomass) and hot gas cleanup, is being developed worldwide to generate power with high efficiency and in an environmentally acceptable manner. The gasifier product gas contains, among others, ammonia and to a lesser extent hydrogen cyanide (HCN) which are converted to oxides of nitrogen (NO{sub x}) when the gas is combusted in the gas turbine. Several nickel-based catalysts were developed and evaluated for decomposition of ammonia present in the gasifier product gas, at Enviropower`s 15 MW{sub th} pilot plant in coal- and biomass-gasification tests. Up to 75% of ammonia in the product gas was decomposed at 800-900{degree}C temperature range and 12-22 bar pressure. 11 refs., 12 figs., 4 tabs.

  15. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    张利斌; 李修伦

    2001-01-01

    A model is proposed to predict boiling heat transfer coefficient in a three-phase circulating fluidized bed (CFB), which is a new type of evaporation boiling means for enhancing heat transfer and preventing fouling. To verify the model, experiments are conducted in a stainless steel column with 39 mm ID and 2.0 m height, in which the heat transfer coefficient is measured for different superficial velocities, steam pressures, particle concentrations and materials of particle. As the steam pressure and particle concentrations increase, the heat transfer coefficient in the bed increases. The heat transfer coefficient increases with the liquid velocity but it exhibits a local minimum.The heat transfer coefficient is correlated with cluster renewed model and two-mechanism method. The prediction of the model is in good agreement with experimental data.

  16. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A model is proposed to predict boiling heat transfer coefficient in a three-phase circulating fluidized bed (CFB), which is a new type of evaporation boiling means for enhancing heat transfer and preventing fouling. To verify the model, experiments are conducted in a stainless steel column with 39mm ID and 2.0m height, in which the heat transfer coefficient is measured for different superficial velocities, steam pressures, particle concentrations and materials of particle. As the steam pressure and particle concentrations increase, the heat transfer coefficient in the bed increases. The heat transfer coefficient increases with the liquid velocity but it exhibits a local minimum. The heat transfer coefficient is correlated with cluster renewed model and two-mechanism method. The prediction of the model is in good agreement with experimental data.

  17. Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Beneficiation. Topical report for Task 4, Beneficiation research

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.J.; Lau, F.S.; Mensinger, M.C. [Institute of Gas Technology, Chicago, IL (United States); Schultz, C.W.; Mehta, R.K.; Lamont, W.E. [Alabama Univ., University, AL (United States); Chiang, S.H.; Venkatadri, R. [Pittsburgh Univ., PA (United States); Misra, M. [Nevada Univ., Reno, NV (United States)

    1992-05-01

    The Mineral Resources Institute at the University of Alabama, along with investigators from the University of Pittsburgh and the University of Nevada-Reno, have conducted a research program on the beneficiation, of Eastern oil shales. The objective of the research program was to evaluate and adapt those new and emerging technologies that have the potential to improve the economics of recovering oil from Eastern oil shales. The technologies evaluated in this program can be grouped into three areas: fine grinding kerogen/mineral matter separation, and waste treatment and disposal. Four subtasks were defined in the area of fine grinding. They were as follows: Ultrasonic Grinding, Pressure Cycle Comminution, Stirred Ball Mill Grinding, and Grinding Circuit Optimization. The planned Ultrasonic grinding research was terminated when the company that had contracted to do the research failed. Three technologies for effecting a separation of kerogen from its associated mineral matter were evaluated: column flotation, the air-sparged hydrocyclone, and the LICADO process. Column flotation proved to be the most effective means of making the kerogen/mineral matter separation. No problems are expected in the disposal of oil shale tailings. It is assumed that the tailings will be placed in a sealed pond and the water recycled to the plant as is the normal practice. It may be advantageous, however, to conduct further research on the recovery of metals as by-products and to assess the market for tailings as an ingredient in cement making.

  18. NO{sub x}, N{sub 2}O and SO{sub 2} emissions from pressurized fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Korpela, T.; Lu, Y. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Economic Energy and Power Plant Engineering

    1996-12-01

    This project continues the analysis of available data from the experimental work at the Otaniemi PFBC test rig using various solid fuels. The study concentrates on the emission and control of NO{sub x} N{sub 2}O, and SO{sub 2} under pressurized conditions. The aim of the study is to prepare the database from the available data and make empirical correlations for estimating nitrogen oxide emissions and sulfur capture from PFBC as a function of significant operating parameters and fuel properties. As the first generation of an empirical model, multiple linear regression was developed for predicting NO{sub x}, N{sub 2}O and SO{sub 2} emissions from PFBC. These correlations may facilitate preliminary FBC design by estimating NO{sub x}, N{sub 2}O and SO{sub 2} emissions. On the basis of statistical inference, the operating conditions employed and the fuel properties selected in the correlations may lend insight into the mechanisms of the formation and destruction of NO{sub x}, N{sub 2}O and SO{sub 2}. (author)

  19. Velocity Fluctuations in Gas-Fluidized Beds

    Science.gov (United States)

    Cody, G. D.

    1998-03-01

    Increasing gas flow through a bed of particles produces, above a sharp threshold, a fluidized state which exhibits many of the properties of a liquid. Fluidized beds play a major role in refining, chemicals, and power generation, but the physics of the fluidized state is still uncertain, due to the complexity of the particle/gas interactions, the broad distribution of particle size, and the measurement challenge. One consequence can be the failure of sophisticated computer models to predict performance. Another is the failure to resolve fundamental questions, for example the source of the initial stability/instability of the uniform fluidized state, first addressed by Jackson in 1963(R. Jackson, in Fluidization, edited by J. F. Davidson et al. (Academic Press, New York, 1985), p. 47-72; G. K. Batchelor, J. Fluid Mech. 193, 75-110 (1988); M. Nicolas. J. Chomaz, and E. Guazelli, Phys. Fluids 6, 3936-3944 (1994).). To meet the measurement challenge, we have obtained the first comprehensive data on the mean squared fluctuation velocity, or granular temperature, T*, of monodispersed glass spheres of diameter, D, in a fluidized bed, by a novel acoustic shot noise probe of random particle impact on the wall(G. D. Cody, D. J. Goldfarb, G. V. Storch, Jr., A. N. Norris, Powder Technology 87, 211-232 (1996); G. D. Cody and D. J. Goldfarb, in Dynamics in Small Confining Systems-III, eds. M. Drake et al, (MRS, Pittsburgh, Pa, 1997), 464, p. 325-338.). Applying a dense gas kinetic model(D. Gidaspow, Multiphase Flow and Fluidization (Academic Press, San Diego, 1994).) to this data predicts values of particulate pressure, and viscosity, which are in excellent agreement with recent experiments, and encouraged us to revisit the stability question. We find that the unanticipated seven-fold bifurcation observed in T* for D less than 150 microns is sufficient, using Jackson's model, to account for the accepted empirical boundary of stable initial uniform fluidization for the spheres

  20. Pulsed atmospheric fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

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

  1. Second generation pressurized fluidized-bed combustion (PFBC) research and development, Phase 2 --- Task 4, carbonizer testing. Volume 2, Data reconciliation

    Energy Technology Data Exchange (ETDEWEB)

    Froehlich, R.; Robertson, A.; Vanhook, J.; Goyal, A.; Rehmat, A.; Newby, R.

    1994-11-01

    During the period beginning November 1991 and ending September 1992, a series of tests were conducted at Foster Wheeler Development Corporation in a fluidized-bed coal carbonizer to determine its performance characteristics. The carbonizer was operated for 533 hours in a jetting fluidized-bed configuration during which 36 set points (steady-state periods) were achieved. Extensive data were collected on the feed and product stream compositions, heating values, temperatures, and flow rates. With these data, elemental and energy balances were computed to evaluate and confirm accuracy of the data. The carbonizer data were not as self-consistent as could be desired (balance closure imperfection). A software package developed by Science Ventures, Inc., of California, called BALAID, was used to reconcile the carbonizer data; the details of the reconciliation have been given in Volume 1 of this report. The reconciled data for the carbonizer were rigorously analyzed, correlations were developed, and the model was updated accordingly. The model was then used in simulating each of the 36 steady-state periods achieved in the pilot plant. The details are given in this Volume one. This Volume 2 provides details of the carbonizer data reconciliation.

  2. Direct iron ore reduction by methane in a fluidized bed. Second annual report, November 1990-November 1991

    Energy Technology Data Exchange (ETDEWEB)

    van der Vaart, D.R.; Conger, W.L.

    1992-02-01

    The partial oxidation and steam reforming of methane was studied in both fixed- and fluidized-bed reactors (both bench-scale). In the absence of iron particles, both pathways were found to produce a mixture of CO and H2 in a proportion consistent with equilibrium calculations at temperatures above 1050 C. When iron oxide particles were added, however, virtually no H2 was detected while the proportion of CO2 and CO depended strongly on the amount of water in the feed stream. Preliminary studies using reduced iron particles indicate that Fe/FeO is an active dissociation catalyst for methane. Finally, a fluidized reactor model has been shown to accurately describe both gas-phase and catalytic reactions in a fluidized bed. In this regard, new theory is presented which can explain the peculiar shape of the axial concentration profile in a fluidized bed as measured by in-bed sampling.

  3. Fluidized-bed combustion process evaluation and program support. Quarterly report, January-March 1980

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, I.; Podolski, W.F.; Swift, W.M.; Henry, R.F.; Hanway, J.E.; Griggs, K.E.; Herzenberg, C.; Helt, J.E.; Carls, E.L.

    1980-12-01

    Argonne National Laboratory is undertaking several tasks primarily in support of the pressurized fluidized-bed combustion project management team at Morgantown Energy Technology Center. Work is under way to provide fluidized-bed combustion process evaluation and program support to METC, determination of the state of the art of instrumentation for FBC applications, evaluation of the performance capability of cyclones for hot-gas cleaning in PFBC systems, and an initial assessment of methods for the measurement of sodium sulfate dew point.

  4. Characterization of fuels for atmospheric fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  5. 气固搅拌流化床内压力脉动特性的数值模拟%Numerical simulation of pressure fluctuation in gas-solids agitated fluidized bed

    Institute of Scientific and Technical Information of China (English)

    顾雪萍; 韩颖; 王嘉骏; 冯连芳

    2013-01-01

    Agitators were introduced to gas-solids fluidized beds to improve fluidization performance and scrape sticky particles from internal bed wall. Numerical simulations based on the computational fluid dynamics (CFD) method were carried out to predict bubble behavior in the agitated fluidized bed. The Euler-Euler two-fluid model and the kinetic theory of granular flow were incorporated to describe the gas-solids flow, whist the multiple reference frame method was applied to deal with the rotation of agitator. The numerical models were validated by bed pressure drop and its fluctuation obtained in the experiment. The bubble behavior and fluidization performance were investigated in terms of pressure fluctuation. The results indicated that the amplitudes of pressure fluctuation and its power spectrum were reduced by increasing agitation speed of frame impeller, while dominating frequency had positive but inconspicuous correlation with agitation. The characteristics of pressure fluctuation showed that bubble size in the fluidized bed went down with a rise in agitation speed, which might lead to the transition from bubbling fluidization to particulate fluidization.%在传统气固流化床中引入搅拌桨,可减轻聚合物颗粒的黏附并强化流态化过程.采用计算流体力学(CFD)方法对搅拌流化床内的压力脉动特性进行数值模拟,考察流态化过程中的气泡行为.模拟过程采用多重参考坐标系方法解决搅拌桨区域的运动问题,由欧拉双流体模型和颗粒动力学方法模拟气固两相流.床层压力脉动的统计分析和功率谱分析表明,随着搅拌桨转速的增加,流化床内的压力脉动标准偏差和功率谱幅值变小,床层内的平均气泡尺寸减小,床层可由鼓泡流态化向散式流态化转变.

  6. Gas cleaning, gas conditioning and tar abatement by means of a catalytic filter candle in a biomass fluidized-bed gasifier.

    Science.gov (United States)

    Rapagnà, Sergio; Gallucci, Katia; Di Marcello, Manuela; Matt, Muriel; Nacken, Manfred; Heidenreich, Steffen; Foscolo, Pier Ugo

    2010-09-01

    A bench-scale fluidized-bed biomass gasification plant, operating at atmospheric pressure and temperature within the range 800-820 degrees C, has been used to test an innovative gas cleaning device: a catalytic filter candle fitted into the bed freeboard. This housing of the gas conditioning system within the gasifier itself results in a very compact unit and greatly reduced thermal losses. Long term (22h) tests were performed on the gasifier both with and without the catalytic candle filter, under otherwise identical conditions. Analysis of the product gas for the two cases showed the catalytic filtration to give rise to notable improvements in both gas quality and gas yield: an increase in hydrogen yield of 130% and an overall increase in gas yield of 69% - with corresponding decreases in methane and tar content of 20% and 79%, respectively. HPLC/UV analysis was used to characterize the tar compounds.

  7. Hydrodynamics of gas-solids downflow fluidized bed (downer) reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.

    1999-07-01

    This study presents a semi-empirical model for the hydrodynamic flow structure in a circulating fluidized bed downer reactor. Circulating fluidized bed, or riser reactors are used in the petroleum industry for many applications including catalytic cracking, polyethylene production, calcination operations and combustion of a variety of fuels. The work in this thesis involved the development of a circulating fluidized bed riser and downer system that enables hydrodynamic studies to be carried out. The system was designed to incorporate both a riser and a downer in the same circulating operation, making it possible to conduct experimental studies on the riser and the downer separately or simultaneously. The hydrodynamics of the gas-solids downflow fluidized bed reactor were studied in a 9.3 m tall and 0.1 m i.d. circulating fluidized bed downer reactor using fluidized cracking catalyst (FCC) particles. In order to characterize the gas-solids flow structures, the following three parameters were measured: the radial distributions of the local solids holdups, the local particle velocities, and the pressure gradients along the downer column. The hydrodynamics in the co-current downflow reactor was also studied under a wide range of operating conditions. The gas-solids flow structure under zero superficial gas velocity conditions was characterized by measuring the radial distribution of the local solids holdups and particle velocities along the downer column with the superficial gas velocity set to zero. The results indicate that two basic flow regimes exist in the FCC downer system depending on the superficial gas velocity. The downer reactor was shown to have a more uniform radial flow structure compared to the riser. It also has a more uniform radial distribution of solids holdup and particle velocity as well as solids flux in both the development and fully developed zones. The highly uniform radial flow structure provides a nearly ideal plug flow condition in the

  8. Modelling and calculation of combined-cycle power plants with pressurized fluidized bed and with upstream or downstream gas turbines at full load and part load; Modellierung und Berechnung von Kombikraftwerken mit Druckwirbelschicht und vor- sowie nachgeschalteten Gasturbinen bei Voll- und Teillast

    Energy Technology Data Exchange (ETDEWEB)

    Faatz, R.

    1997-12-31

    Owing to their high efficiency, low pollutant emissions and good performance when fuelled with coal, pressurized fluidized-bed combustors have come to play and important role. The performance of processes with pressurized fluidized beds can be enhanced significantly by combining them with gas turbines fuelled with natural gas or coal gas. The report describes several variants of combined cycle processes with pressurized fluidized beds and with gas turbines connected upstream or downstream. The main components, i.e. gas turbine, pressurized fluidized bed, steam turbine and steam cycle are simulated by computer models. For the power plant variants, full-load calculations were carried out to determine the potential efficiency; for the components like gas turbine and pressurized fluidized bed, also part-load calculations were made. It was found that efficiencies of 45-49 % are possible with the investigated variants. Optimisation of the process parameters, efficiencies up to 51.4 % will be possible especially in the range of transition to supercritical steam parameters. (orig.) 68 figs., 14 tabs. [Deutsch] Die Druckwirbelschichtfeuerung hat wegen ihres hohen Wirkungsgrades, ihrer niedrigen Schadstoffemissionen und ihrer Eignung fuer den Brennstoff Kohle eine grosse Bedeutung erlangt. Durch geschickte Kombination mit erdgas- oder kohlegasgefeuerten Gasturbinen laesst sich der Wirkungsgrad von Prozessen mit Druckwirbelschicht betraechtlich steigern. Die vorliegende Arbeit beschreibt verschiedene Schaltungsvarianten von Kombiprozessen mit Druckwirbelschicht, bei denen die Gasturbinen der Wirbelschicht sowohl vorgeschaltet als auch nachgeschaltet sind. Die Hauptkomponenten der Prozesse wie Gasturbine, Druckwirbelschicht, Dampfturbine und Dampfkreislauf werden durch Rechnermodelle simuliert. Fuer die Kraftwerksvarianten wurden Vollastrechnungen zur Ermittlung des Wirkungsgradpotentials, fuer die einzelnen Komponenten wie Gasturbine und Druckwirbelschicht auch

  9. Computational and Experimental Study of Spherocylinder Particles in Fluidized Beds

    Science.gov (United States)

    Mahajan, Vinay; Kuipers, Hans; Padding, Johan; Multiphase Reactors Group, TU Eindhoven Team

    2016-11-01

    Non-spherical particle flows are often encountered in fluidized process equipment. A coupled computational fluid dynamics (CFD) and discrete element method(DEM) approach has been extensively applied in recent years to study these flows at the particle scale. However, most of these studies focus on spherical particles while in reality, the constituent particles are seldom spherical. Particle shape can significantly affect the hydrodynamical response in fluidized beds. The drag force acting on a non-spherical particle can vary considerably with particle shape, orientation of the particle, Reynolds number and packing fraction. In this work, a CFD-DEM approach has been extended to model a lab scale quasi-2D fluidized bed of spherocylinder (rod-like) particles. These particles can be classified as Geldart D particles and have an aspect ratio of 4. Numerical results for the pressure drop, bed height and solid circulation patterns are compared with results from a complementary laboratory experiment. We also present results on particle orientations close to the confining walls, which provides interesting insight regarding the particle alignment. Thus the capability of the CFD-DEM approach to efficiently account for global bed dynamics in fluidized bed of rod-like particle is demonstrated. This research work is funded by ERC Grant.

  10. Wear prediction in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  11. Fast Pyrolysis Process Development Unit for Validating Bench Scale Data

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Robert C. [Iowa State Univ., Ames, IA (United States). Biorenewables Research Lab.. Center for Sustainable Environmental Technologies. Bioeconomy Inst.; Jones, Samuel T. [Iowa State Univ., Ames, IA (United States). Biorenewables Research Lab.. Center for Sustainable Environmental Technologies. Bioeconomy Inst.

    2010-03-31

    The purpose of this project was to prepare and operate a fast pyrolysis process development unit (PDU) that can validate experimental data generated at the bench scale. In order to do this, a biomass preparation system, a modular fast pyrolysis fluidized bed reactor, modular gas clean-up systems, and modular bio-oil recovery systems were designed and constructed. Instrumentation for centralized data collection and process control were integrated. The bio-oil analysis laboratory was upgraded with the addition of analytical equipment needed to measure C, H, O, N, S, P, K, and Cl. To provide a consistent material for processing through the fluidized bed fast pyrolysis reactor, the existing biomass preparation capabilities of the ISU facility needed to be upgraded. A stationary grinder was installed to reduce biomass from bale form to 5-10 cm lengths. A 25 kg/hr rotary kiln drier was installed. It has the ability to lower moisture content to the desired level of less than 20% wt. An existing forage chopper was upgraded with new screens. It is used to reduce biomass to the desired particle size of 2-25 mm fiber length. To complete the material handling between these pieces of equipment, a bucket elevator and two belt conveyors must be installed. The bucket elevator has been installed. The conveyors are being procured using other funding sources. Fast pyrolysis bio-oil, char and non-condensable gases were produced from an 8 kg/hr fluidized bed reactor. The bio-oil was collected in a fractionating bio-oil collection system that produced multiple fractions of bio-oil. This bio-oil was fractionated through two separate, but equally important, mechanisms within the collection system. The aerosols and vapors were selectively collected by utilizing laminar flow conditions to prevent aerosol collection and electrostatic precipitators to collect the aerosols. The vapors were successfully collected through a selective condensation process. The combination of these two mechanisms

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

    Science.gov (United States)

    Broqueville, Axel De; Wilde, Juray De

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

  13. Flow Pattern Identification of Fluidized Beds Using ECT

    Institute of Scientific and Technical Information of China (English)

    S. Liu; W.Q. Yang; H. Wang; G. Yan; Z. Pan

    2001-01-01

    Electrical capacitance tomography (ECT) was applied in measuring solids distribution in square circulating fluidized beds. The fluidization conditions varied from bubbling fluidized bed to circulating fluidized bed. In the whole range of fluidization conditions, ECT was able to instantaneously provide the solids concentration and voids distributions in the fluidized beds. According to the acquired data from ECT and reconstructed image,different fluidization regimes can also be identified.

  14. Performance analysis of K-based KEP-CO2P1 solid sorbents in a bench-scale continuous dry-sorbent CO{sub 2} capture process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Young Cheol; Jo, Sung-Ho; Lee, Seung-Yong; Moon, Jong-Ho; Yi, Chang-Keun [Korea Institute of Energy Research, 152, Gajeong-ro, Yuseong-gu, Daejeon (Korea, Republic of); Ryu, Chong Kul; Lee, Joong Beom [Korea Electric Power Corporation Research Institute, Daejeon (Korea, Republic of)

    2016-01-15

    Korea Institute of Energy Research (KIER) and Korea Electric Power Corporation Research Institute (KEPCORI) have been developing a CO{sub 2} capture technology using dry sorbents. In this study, KEP-CO2P1, a potassium-based dry sorbent manufactured by a spray-drying method, was used. We employed a bench-scale dry-sorbent CO{sub 2} capture fluidized-bed process capable of capturing 0.5 ton CO{sub 2}/day at most. We investigated the sorbent performance in continuous operation mode with solid circulation between a fast fluidized-bed-type carbonator and a bubbling fluidizedbed- type regenerator. We used a slip stream of a real flue gas from 2MWe coal-fired circulating fluidized-bed (CFB) power facilities installed at KIER. Throughout more than 50 hours of continuous operation, the temperature of the carbonator was maintained around 70-80 .deg. C using a jacket-type heat exchanger, while that of the regenerator was kept above 180 .deg. C using an electric furnace. The differential pressure of both the carbonator and regenerator was maintained at a stable level. The maximum CO{sub 2} removal was greater than 90%, and the average CO{sub 2} removal was about 83% during 50 hours of continuous operation.

  15. 21 CFR 890.5160 - Air-fluidized bed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Air-fluidized bed. 890.5160 Section 890.5160 Food... DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed. (a) Identification. An air-fluidized bed is a device employing the circulation of filtered air through...

  16. Standby cooling system for a fluidized bed boiler

    Science.gov (United States)

    Crispin, Larry G.; Weitzel, Paul S.

    1990-01-01

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

  17. Some hydrodynamic aspects of 3-phase inverse fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Hydrodynamics of 3-phase inverse fluidized bed is studied experimentally using low density particles for different liquid and gas velocities.The hydrodynamic characteristics studied include pressure drop, minimum liquid and gas fluidization velocities and phase holdups. The minimum liquid fluidization velocity determined using the bed pressure gradient, decreases with increase in gas velocity. The axial profiles of phase holdups shows that the liquid holdup increases along the bed height, whereas the solid holdup decreases down the bed. However, the gas holdup is almost uniform in the bed.

  18. Analysis of Probability Density of Pressure Fluctuation Signal’ s Spectral Energy in Fluidized Bed%流化床压力脉动信号谱能量的概率密度分析

    Institute of Scientific and Technical Information of China (English)

    周云龙; 王芳

    2014-01-01

    在自行搭建冷态流化床实验台的基础上,采集了不同压力测点处的压力脉动信号。通过对比、分析流化床风帽入口与床壁测点处压力信号的频谱图,得到了不同压力测点传达相同流动特性信息的结论。结合Welch算法的谱估计和t分布下的概率密度函数,对所采集到的压力脉动信号进行累积概率分布的对比和分析。结果表明:在压力信号Welch谱估计的能量累积概率分布图中,能够很容易地观察到流化床内流动状态的变化,为以后识别多相流流型提供了新的途径。%Basing on the self-designed fluidized bed experimental rig, the pressure fluctuation signals at differ-ent pressure test points were collected.Through comparing and analyzing the recurrence plots of pressure sig-nals at different test points, the conclusion that pressure signals at different test points convey the same infor-mation of flow characteristics was reached.Having the probability density function under the Student’ s t-distri-bution combined with the spectral estimation of Welch algorithm to contrast and analyze the cumulative proba-bility distributions of pressure fluctuant signals shows that, in the energy cumulative probability distribution map of Welch spectrum estimation, the changing of flow state in fluidized bed can be easily observed, this pro-vides a new approach to the identification of multiphase flow.

  19. IHI-FW circulating fluidized bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S.; Omata, K.; Ishimoto, R.; Asai, M. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))

    1993-07-01

    The technology and application of the circulating fluidized bed boiler (IHI-FW) are outlined. Circulating fluidized bed boilers have various features as compared with bubbling fluidized bed boilers as follows; a high combustion efficiency, efficient use of limestone for desulfurization, low NOx emission, adaptability to various fuels and capability to cope with load change. The IHI-FW boiler is furthermore featured by water-wall furnace of all-welded structure, water-cooled/steam cooled cyclone, and simple circulating system. The 30 t/h circulating fluidized bed boiler was introduced into the Tsu Works, Omikenshi Co., Ltd., Japan for private power generation. The boiler equipped with a backup heavy oil burner mainly uses semi-anthracite coal, and besides sulfur capture and NOx reduction functions of a bed, a bag filter with a high dust collecting efficiency is installed in an exhaust gas system. The installation period was reduced to 2.5 months, a half of conventional ones, by more assembly in a factory followed by less field works. 7 figs., 2 tabs.

  20. Modelling of Devolatilization in Fluidized Bed Combustion

    DEFF Research Database (Denmark)

    Stenseng, Mette; Lin, Weigang; Johnsson, Jan Erik

    1997-01-01

    A mathematical model is developed to describe the devolatilization process in a circulating fluidized bed combustor. The model is a combination of two submodels: single particle devolatilization and fluid dynamics. The single particle model includes the influence of both chemical kinetics and hea...

  1. Multiscale modeling of gas-fluidized beds

    NARCIS (Netherlands)

    Hoef, van der M.A.; Sint Annaland, van M.; Andrews, A.T.; Sundaresan, S.; Kuipers, J.A.M.

    2006-01-01

    Numerical models of gas-fluidized beds have become an important tool in the design and scale up of gas-solid chemical reactors. However, a single numerical model which includes the solid-solid and solid-fluid interaction in full detail is not feasible for industrial-scale equipment, and for this rea

  2. Agglomeration in fluidized beds: detection and counteraction

    NARCIS (Netherlands)

    Bartels. M.

    2008-01-01

    Fluidized beds comprise a quantity of solid particles that is suspended by an upward flowing gas. They are used for a variety of processes in the chemical industry, such as catalytic reactions, drying, coating and energy conversion. A major problem in industrial practice is the occurrence of unwante

  3. Control of fluidized bed tea drying

    NARCIS (Netherlands)

    Temple, S.J.

    2000-01-01

    Tea is a product made from the leaf of the tea bush by several processes, including drying. The drying stage is the most energy intensive, and has tight performance criteria. This project investigated the options for the control of a fluidized bed tea dryer. The work included establishing some of th

  4. Calcium sulphoaluminate cement made from fluidized bed combustion wastes

    Energy Technology Data Exchange (ETDEWEB)

    Bernards, G.; Marroccoli, M.; Montagnaro, F.; Valenti, G.L.

    2000-07-01

    Wastes generated in a bench-scale atmospheric fluidized bed combustor, using two different coals (one from Poland and one from South Africa) and a high-lime limestone sorbent, were employed as raw materials for the synthesis of calcium sulphoaluminate (4 CaO{sub 3} Al{sub 2}O{sub 3}.SO{sub 3})-based cements, which can be utilized for a wide range of applications. Raw mixes containing the bed material were heated in an electric oven in the temperature range 1000-1200{degree}C. The best results in terms of reactants conversion and selectivity towards 4 CaO{sub 2} Al{sub 2}O{sub 3}.SO{sub 3} were obtained at 1200{degree}C with the addition of an external source of alumina which was required to avoid melting phenomena or integrate the Al{sub 2}O{sub 3} content necessary for the 4CaO{sub 3}.Al{sub 2}O{sub 3}-SO{sub 3} formation. 7 refs., 7 tabs.

  5. Support studies in fluidized-bed combustion. Quarterly report, April-June 1979

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, I.; Lenc, J.F.; Shearer, J.A.; Smith, G.W.; Swift, W.M.; Teats, F.G.; Turner, C.B.; Jonke, A.A.

    1979-01-01

    This work supports the development studies for atmospheric and pressurized fluidized-bed coal combustion. Laboratory and process development studies are aimed at providing needed information on limestone utilization, removal of particulates and alkali 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 removal of particulate emissions from pressurized fluidized-bed combustion flue gas using a commercially available high-efficiency cyclone (TAN-JET), and (2) the results of laboratory and process development unit studies to determine the effects of CaCl/sub 2/, Na/sub 2/CO/sub 3/, NaCl, and H/sub 2/O treatments on increasing the utilization of limestone.

  6. Pilot plant testing of IGT`s two-stage fluidized-bed/cyclonic agglomerating combustor

    Energy Technology Data Exchange (ETDEWEB)

    Rehmat, A.; Mensinger, M.C. [Institute of Gas Technology, Chicago, IL (United States); Richardson, T.L. [Environmental Protection Agency, Cincinnati, OH (United States)

    1993-12-31

    The Institute of Gas Technology (IGT) is conducting a multi-year experimental program to develop and test, through pilot-scale operation, IGT`s two-stage fluidized-bed/cyclonic agglomerating combustor (AGGCOM). The AGGCOM process is based on combining the fluidized-bed agglomeration and gasification technology with the cyclonic combustion technology, both of which have been developed at IGT over many years. AGGCOM is a unique and extremely flexible combustor that can operate over a wide range of conditions in the fluidized-bed first stage from low temperature (desorption) to high temperature (agglomeration), including gasification of high-energy-content wastes. The ACCCOM combustor can easily and efficiently destroy solid, liquid, and gaseous organic wastes, while isolating solid inorganic contaminants within an essentially non-leachable glassy matrix, suitable for disposal in ordinary landfills. Fines elutriated from the first stage are captured by a high-efficiency cyclone and returned to the fluidized bed for ultimate incorporation into the agglomerates. Intense mixing in the second-stage cyclonic combustor ensures high destruction and removal efficiencies (DRE) for organic compounds that may be present in the feed material. This paper presents an overview of the experimental development of the AGGCOM process and progress made to date in designing, constructing, and operating the 6-ton/day AGGCOM pilot plant. Results of the bench-scale tests conducted to determine the operating conditions necessary to agglomerate a soil were presented at the 1991 Incineration Conference. On-site construction of the AGGCOM pilot plant was initiated in August 1992 and completed at the end of March 1993, with shakedown testing following immediately thereafter. The initial tests in the AGGCOM pilot plant will focus on the integrated operation of both stages of the combustor and will be conducted with ``clean`` topsoil.

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

    Science.gov (United States)

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

    2015-02-01

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

  8. Internal Combustion Engines as Fluidized Bed Reactors

    Science.gov (United States)

    Lavich, Zoe; Taie, Zachary; Menon, Shyam; Beckwith, Walter; Daly, Shane; Halliday, Devin; Hagen, Christopher

    2016-11-01

    Using an internal combustion engine as a chemical reactor could provide high throughput, high chemical conversion efficiency, and reactant/product handling benefits. For processes requiring a solid catalyst, the ability to develop a fluidized bed within the engine cylinder would allow efficient processing of large volumes of fluid. This work examines the fluidization behavior of particles in a cylinder of an internal combustion engine at various engine speeds. For 40 micron silica gel particles in a modified Megatech Mark III transparent combustion engine, calculations indicate that a maximum engine speed of about 60.8 RPM would result in fluidization. At higher speeds, the fluidization behavior is expected to deteriorate. Experiments gave qualitative confirmation of the analytical predictions, as a speed of 48 RPM resulted in fluidized behavior, while a speed of 171 RPM did not. The investigation shows that under certain conditions a fluidized bed can be obtained within an engine cylinder. Corresponding Author.

  9. Rapid ignition of fluidized bed boiler

    Science.gov (United States)

    Osborn, Liman D.

    1976-12-14

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

  10. Pressurized fluidized-bed hydroretorting of eastern oil shales. Volume 4, Task 5, Operation of PFH on beneficiated shale, Task 6, Environmental data and mitigation analyses and Task 7, Sample procurement, preparation, and characterization: Final report, September 1987--May 1991

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The objective of Task 5 (Operation of Pressurized Fluidized-Bed Hydro-Retorting (PFH) on Beneficiated Shale) was to modify the PFH process to facilitate its use for fine-sized, beneficiated Eastern shales. This task was divided into 3 subtasks: Non-Reactive Testing, Reactive Testing, and Data Analysis and Correlations. The potential environment impacts of PFH processing of oil shale must be assessed throughout the development program to ensure that the appropriate technologies are in place to mitigate any adverse effects. The overall objectives of Task 6 (Environmental Data and Mitigation Analyses) were to obtain environmental data relating to PFH and shale beneficiation and to analyze the potential environmental impacts of the integrated PFH process. The task was divided into the following four subtasks. Characterization of Processed Shales (IGT), 6.2. Water Availability and Treatment Studies, 6.3. Heavy Metals Removal and 6.4. PFH Systems Analysis. The objective of Task 7 (Sample Procurement, Preparation, and Characterization) was to procure, prepare, and characterize raw and beneficiated bulk samples of Eastern oil shale for all of the experimental tasks in the program. Accomplishments for these tasks are presented.

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

    Science.gov (United States)

    Cheng, George Shu-Xing; Mulkey, Steven L

    2014-12-16

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

  12. Cocurrent downflow circulating fluidized bed (downer) reactors - a state of the art review

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J.-X.; Yu, Z.-Q.; Jin, Y.; Grace, J.R.; Issangya, A. [University of Western Ontario, London, ON (Canada). Department of Chemical and Biochemical Engineering

    1995-10-01

    A new type of chemical reactor known as the cocurrent downflow fluidized bed reactor (or reversed riser reactor or downer reactor), that overcomes some of the disadvantages of the riser reactor, is described. Since both the gas and solids flow directions are downwards in the cocurrent downflow fluidized bed reactor, particle residence times are uniform, and there is no backmixing. The literature on downer studies is reviewed. Laboratory results on axial voidage profiles, pressure profiles, radial flow, mixing and residence time distribution, heat transfer, and particle velocities are summarized. Suggestions are made both for possible industrial applications of downer reactors and for suitable research directions. 56 refs., 18 figs., 1 tab.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-12-01

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

  14. Biological denitrification in a fluidized bed.

    Science.gov (United States)

    Narjari, N K; Khilar, K C; Mahajan, S P

    1984-12-01

    A fluidized bed biofilm reactor using sand as the carrier particle was employed to study the effects of superficial velocity on the removal of nitrates as well as on the growth of the biofilm. Velocity was found to affect significantly both nitrate removal and biofilm growth. An analysis based on heterogenous catalysis was used to describe the denitrification process. There is good agreement between analysis and experimental measurements for startup and steady-state operating conditions.

  15. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

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

  16. Circulating fluidized bed boilers design and operations

    CERN Document Server

    Basu, Prabir

    1991-01-01

    This book provides practicing engineers and students with insight into the design and operation of circulating fluidized bed (CFB) boilers. Through a combination of theoretical concepts and practical experience, this book gives the reader a basic understanding of the many aspects of this subject.Important environmental considerations, including solid waste disposal and predicted emissions, are addressed individually in separate chapters. This book places an emphasis on combustion, hydrodynamics, heat transfer, and material issues, and illustrates these concepts with numerous examples of pres

  17. Bench-Scale Development of a Hot Carbonate Absorption Process with Crystallization-Enabled High-Pressure Stripping for Post-Combustion CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yongqi; DeVries, Nicholas; Ruhter, David; Manoranjan, Sahu; Ye, Qing; Ye, Xinhuai; Zhang, Shihan; Chen, Scott; Li, Zhiwei; O' Brien, Kevin

    2014-03-31

    A novel Hot Carbonate Absorption Process with Crystallization-Enabled High-Pressure Stripping (Hot-CAP) has been developed by the University of Illinois at Urbana-Champaign and Carbon Capture Scientific, LLC in this three-year, bench-scale project. The Hot-CAP features a concentrated carbonate solution (e.g., K{sub 2}CO{sub 3}) for CO{sub 2} absorption and a bicarbonate slurry (e.g., KHCO{sub 3}) for high-pressure CO{sub 2} stripping to overcome the energy use and other disadvantages associated with the benchmark monoethanolamine (MEA) process. The project was aimed at performing laboratory- and bench-scale experiments to prove its technical feasibility and generate process engineering and scale-up data, and conducting a techno-economic analysis (TEA) to demonstrate its energy use and cost competitiveness over MEA. To meet project goals and objectives, a combination of experimental, modeling, process simulation, and economic analysis studies were applied. Carefully designed and intensive experiments were conducted to measure thermodynamic and reaction engineering data relevant to four major unit operations in the Hot-CAP (i.e., CO{sub 2} absorption, CO{sub 2} stripping, bicarbonate crystallization, and sulfate reclamation). The rate promoters that could accelerate the CO{sub 2} absorption rate into the potassium carbonate/bicarbonate (PCB) solution to a level greater than that into the 5 M MEA solution were identified, and the superior performance of CO{sub 2} absorption into PCB was demonstrated in a bench-scale packed-bed column. Kinetic data on bicarbonate crystallization were developed and applied for crystallizer design and sizing. Parametric testing of high-pressure CO{sub 2} stripping with concentrated bicarbonate-dominant slurries at high temperatures ({>=}140{degrees}C) in a bench-scale stripping column demonstrated lower heat use than with MEA. The feasibility of a modified process for combining SO{sub 2} removal with CO{sub 2} capture was preliminarily

  18. Status of the fluidized bed unit

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-06-01

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

  19. Nitric oxide reduction over biomass and coal chars under fluidized bed combustion conditions: the role of thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Piero Salatino; Anna Di Somma; Roberto Solimene; Riccardo Chirone [Universita degli Studi di Napoli Federico II, Napoli (Italy). Dipartimento di Ingegneria Chimica

    2008-07-01

    The de-NOx potential of biomass-and waste-derived fuels candidate for cofiring with coal is assessed. The experimental procedure is based on operation of a bench scale fluidized bed reactor where NO-doped nitrogen is contacted with batches of the fuel. A second type of experiment has been purposely designed to assess the extent of thermodeactivation of biogenous fuels, i.e. the loss of reactivity toward the NOx-char reaction as char is annealed for pre-set times at temperatures typical of fluidized bed combustion. A simple phenomenological model is developed to shed light on the basic features of the interaction between heterogeneous char-NOx reaction and thermal annealing of the char. Results are discussed in the light of the potential exploitation of synergistic effects on NOx emission associated with cofiring with coal. 21 refs., 8 figs., 1 tab.

  20. Minimum slugging velocity in fluidized beds containing vertical rods

    Energy Technology Data Exchange (ETDEWEB)

    Coronella, C.J.; Lee, S.Y.; Seader, J.D. (University of Utah, Salt Lake City, UT (United States). Dept. of Chemical Engineering)

    1994-09-01

    A new method for determining the onset of slugging in fluidized beds is presented. Pressure-drop fluctuations, measured from below the distributor to the gas exit line, are transformed to the frequency domain by the power spectral desity function (PSDF). The dominant frequency of the PSDF corresponds to the eruption frequency of bubbles or slugs. A fluidized bed is in the slugging regime when this dominant frequency, f[sub d], remains constant with changing gas velocity. This method is an improvement over previous methods because of the simple nature of the apparatus required, and because it is possible to locate the pressure probes so that they do not interfere with the fluidization or undergo rapid wear from the constant particle movement. This method was used to determine the gas velocity corresponding to the transition from the bubbling to the slugging regime for a 10cm diameter bed of sand fluidized with air and containing three 1.9cm diameter vertical rods at 5.2cm centre-to-centre triangular spacing and extending the length of the bed, and to compare the results with those from the same bed without any internal rods. The presence of the vertical rods inhibited the onset of the slugging regime, and significantly extended the bubbling regime to higher gas velocities. 32 refs., 12 figs.

  1. Fluidized Bed Asbestos Sampler Design and Testing

    Energy Technology Data Exchange (ETDEWEB)

    Karen E. Wright; Barry H. O' Brien

    2007-12-01

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

  2. Fluidized Bed Sputtering for Particle and Powder Metallization

    Science.gov (United States)

    2013-04-01

    Fluidized Bed Sputtering for Particle and Powder Metallization by Daniel M. Baechle, J. Derek Demaree, James K. Hirvonen, and Eric D...5069 ARL-TR-6435 April 2013 Fluidized Bed Sputtering for Particle and Powder Metallization Daniel M. Baechle, J. Derek Demaree, James K...YYYY) April 2013 2. REPORT TYPE Final 3. DATES COVERED (From - To) June 2008–June 2012 4. TITLE AND SUBTITLE Fluidized Bed Sputtering for

  3. Development of pressurized fluidized-bed combustion (PFBC) technology for coal-fired combined cycles. Final report; Entwicklung der Druckwirbelschicht-Feuerungstechnik fuer kohlegefeuerte kombinierte Gas-Dampfprozesse. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Terhaag, U.; Verweyen, N.; Goermar, H.; Bu Cheng; Ewes, I.; Braun, A.

    1992-06-01

    Pressurized fluidized combustion is a very essential component for combined cycles with low emissions and high efficiency. The aim of this project was further development of the stationary pressurized fluidized bed combustion technique. In the last two heating periods, a series of experiments was carried out with modifications of the combustion chamber. The results of these runs were compared with numerical simulations. Improved numerical procedures were used to develop a new design of the pressurized combustion chamber. Attention is focused on emission control for the components CO, NO{sub x} and N{sub 2}O. The necessary modifications, however, result in an increase of the prognosted construction costs, so that the project was finished by the end of 1991. (orig.) With 15 refs., 2 tabs., 120 figs. [Deutsch] Im Rahmen fortschrittlicher Kohleumwandlungsprozesse liefert die druckaufgeladene Wirbelschicht einen wesentlichen Beitrag zur Verringerung der Emissionen und zur Erreichung hoher Wirkungsgrade. Die Weiterentwicklung der stationaeren Druckwirbelschicht-Feuerungstechnik war Ziel dieses Forschungsvorhabens. Dazu sind in den Heizperioden 89/90 und 90/91 umfangreiche numerische und experimentelle Untersuchungen durchgefuehrt und ausgewertet worden. Die Auslegungsprogramme sind so modifiziert worden, dass beliebige stationaere Betriebspunkte nachgerechnet werden koennen. Mit Hilfe dieses Werkzeugs ist mit der Auslegung eines Dampferzeugers mit in Hinblick auf Teillastverhalten und Schadstoffemission optimierten Leistungsmerkmalen begonnen worden. Es hat sich dabei gezeigt, dass die notwendigen baulichen Aenderungen an der Anlage der RWTH Aachen zu einer erheblichen Kostensteigerung fuehren wuerden. Aus diesem Grund ist das Projekt vorzeitig zum 31.12.1991 beendet worden. (orig.) With 15 refs., 2 tabs., 120 figs.

  4. Fluidized-bed reactors processes and operating conditions

    CERN Document Server

    Yates, John G

    2016-01-01

    The fluidized-bed reactor is the centerpiece of industrial fluidization processes. This book focuses on the design and operation of fluidized beds in many different industrial processes, emphasizing the rationale for choosing fluidized beds for each particular process. The book starts with a brief history of fluidization from its inception in the 1940’s. The authors present both the fluid dynamics of gas-solid fluidized beds and the extensive experimental studies of operating systems and they set them in the context of operating processes that use fluid-bed reactors. Chemical engineering students and postdocs as well as practicing engineers will find great interest in this book.

  5. Particle Flow Cell Formation at Minimum Fluidization Flow Rates in a Rectangular Gas-Fluidized Bed.

    Science.gov (United States)

    1981-03-01

    Kunii and Levenspiel Model ----------------- 66 C. FLUIDIZED BED VARIABLES THAT AFFECT HEAT TRANSFER ---------------------------------- 69 5 1...and Levenspiel Model -------------------------- 68 25. Heat transfer coefficient vs. mass velocity --------- 72 26. Contact geometry of surface-particle...becomes a very important factor. According to Kunii and Levenspiel [34], distributors should have a sufficient pressure drop to achieve equal flow

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

    Energy Technology Data Exchange (ETDEWEB)

    Panday, R [West Virginia Univ., Morgantown, WV (United States); Woerner, B D [West Virginia Univ., Morgantown, WV (United States); Ludlow, J C [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Shadle, L J [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Boyle, E J [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2009-02-01

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

  7. Pulsed atmospheric fluidized bed combustion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

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

  8. Transients in a circulating fluidized bed boiler

    Science.gov (United States)

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

    2013-11-01

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

  9. CFD study of a fluidized bed

    OpenAIRE

    Lundberg, Joachim

    2008-01-01

    The aim of this thesis is to investigate the momentum exchange between the phases in a bubbling fluidized bed. The momentum exchange can be described by a drag model. Several drag models with different assumptions are developed. The drag models investigated in this work is the Syamlal O’Brien model, the Gidaspow model, Hill Koch Ladd model, the RUC model and an iterative version of the Syamlal O’Brien called the Richardson Zaki model. The models have been derived and studied in de...

  10. Nucla circulating atmospheric fluidized bed demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-31

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

  11. Packed fluidized bed blanket for fusion reactor

    Science.gov (United States)

    Chi, John W. H.

    1984-01-01

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

  12. Second-generation pressurized fluidized-bed combustion plant: Conceptual design and optimization of a second-generation PFB combustion plant. Phase 2, Annual report, October 1991--September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, A.; Domeracki, W.; Newby, R.; Rehmat, A.; Horazak, D.

    1992-10-01

    After many years of experimental testing and development work, coal-fired pressurized fluidized bed (PFB) combustion combined-cycle power plants are moving toward reality. Under the US Department of Energy`s Clean Coal Technology Program, a 70-MWe PFB combustion retrofit, utilizing a 1525{degrees}F gas turbine inlet temperature, has been built and operated as a demonstration plant at the American Electric Power Company`s Tidd Plant in Brilliant, Ohio. As PFB combustion technology moves closer and closer to commercialization, interest is turning toward the development of an even more efficient and more cost-effective PFB combustion plant. The targeted goals of this ``second-generation`` plant are a 45-percent efficiency and a cost of electricity (COE) that is at least 20 percent lower than the COE of a conventional pulverized-coal (PC)-fired plant with stack gas scrubbing. In addition, plant emissions should be within New Source Performance Standards (NSPS) and the plant should have high availability, be able to burn different ranks of coal, and incorporate modular construction technologies. In response to this need, a team of companies led by Foster Wheeler Development Corporation (FWDC). The key components in the proposed second-generation plant are the carbonizer, CPFBC, ceramic cross-flow filter, and topping combustor. Unfortunately, none of these components has been operated at proposed plant operating conditions, and experimental tests must be conducted to explore/determine their performance throughout the proposed plant operating envelope. The major thrust of Phase 2 is to design, construct, test, and evaluate the performance of the key components of the proposed plant.

  13. Comparison of Fixed and Fluidized Beds Adsorber with Economic, Engineering, and Environmental approach

    Directory of Open Access Journals (Sweden)

    SEDIGHEH ATRKAR-ROSHAN

    2015-10-01

    Full Text Available Release  Volatile  organic  compounds  (VOCs  as  environmental  and  occupational  pollutant  cause  macro perspective affect such as climate change, humans and economic consequences. Although fixed bed absorber is widely used as a controlling method because of its economically and availability, but these absorbers are facing some issue like high pressure drop, non-uniform distribution of fluid, channeling and blocking. Fixed and fluidized beds adsorbent was compared from three economic, environmental and engineering perspectives using Multi Criteria Decision Making analysis (MCDA technique. An annular fluidized bed adsorber was designed and charged with 50-100 µm (100-140 ASTM mesh activated carbon (AC particles. Effects of factors like flow rate, particle size, inlet concentration and adsorption capacity of VOCs was investigated under steady state. In the flow rate less than 0.25(Lit.min-1, inlet gas slowly passes through the void spaces of the bed’s particles. By increasing the inlet flow from 0.3(Lit/min-1, bubbles start to form in the bed and the bed pressure drop decrease. The pressure drop of 6 (g of AC in minimum fluidization velocity was 20(KN.m-2. However, the pressure drop of 10 and 20(g of AC were 150 and 420(KN.m-2 respectively. “maximin” technique used for comparison of two beds indicated that minimum score of pack bed absorber are 0.37 while the minimum score of fluidized bed adsorber are 0.5. It indicated when the adsorbent particles are smaller, fluidized bed adsorber are more suitable to use. In addition, using MCDA technique indicated that annular fluidized bed adsorber could considered as an alternative of fixed beds adsorber.

  14. Heat flux distribution on circulating fluidized bed boiler water wall

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The future of circulating fluidized bed (CFB)combustion technology is in raising the steam parameters to supercritical levels.Understanding the heat flux distribution on the water wall is one of the most important issues in the design and operation of supercritical pressure CFB boilers.In the present paper,the finite element analysis (FEA) method is adopted to predict the heat transfer coefficient as well as the heat flux of the membrane wall and the results are validated by direct measurement of the temperature around the tube.Studies on the horizontal heat flux distribution were conducted in three CFB boilers with different furnace size,tube dimension and water temperature.The results are useful in supercritical pressure CFB boiler design.

  15. Validation of Eulerian modeling of gas-solid fluidized beds using nonlinear analysis

    Science.gov (United States)

    Norouzi, Y.; Norouzi, H. R.; Zarghami, R.

    2015-03-01

    In the present work, the new advanced method has been used for validation of two-fluid method (TFM) for modeling of the hydrodynamics of gas-solid fluidized beds. While many investigations were addressed validation of the CFD codes, less effort has been made to validate the nonlinear dynamics of fluidized beds with nonlinear methods. In this work new advanced nonlinear methods of recurrence plot (RP) and recurrence quantification analysis (RQA) have been used to validate the hydrodynamics modeling of the gas-solid fluidized beds. Pressure fluctuations of inside the bed were selected for comparing the nonlinear dynamics of fluidized bed in experiments and simulations. Pressure fluctuations were measured in a rectangle fluidized bed containing Geldart's group B particles with sampling frequency 400 Hz. Simulations were done with the same operating condition and pressure fluctuations were recorded with the same sampling frequency. The superficial air velocity range was 0.25-0.73 m/s (bubbling regime) and two aspect ratios 1 and 1.5 were used. The results of experiments and simulations were analyzed by RP and RQA. The values of laminarity, determinism, and recurrence rate for both experiments and simulations are close to each other. The experimental and simulation results showed high values for determinism and laminarity which show predictable and periodic behaviors of both systems. High values of determinism and laminarity are one of the most important characteristics of bubbling regime in which bubbles are periodically produced and move in the bed. In the entire gas velocity, the values of determinism and laminarity were not changed significantly that shows that no regime change occurred in the bed.

  16. CFD simulation of a gas-solid fluidized bed with two vertical jets

    Institute of Scientific and Technical Information of China (English)

    Pei Pei; Kai Zhang; Jintian Ren; Dongsheng Wen; Guiying Wu

    2010-01-01

    A computational fluid dynamics(CFD)model is used to investigate the hydrodynamics of a gas-solid fluidized bed with two vertical jets.Sand particles with a density of 2660 kg/m3 and a diameter of5.0 × 10-4 m are employed as the solid phase.Numerical computation is carried out in a 0.57 m × 1.00 m two-dimensional bed using a commercial CFD code.CFX 4.4,together with user-defined Fortran subrou-tines.The applicability of the CFD model is validated by predicting the bed pressure drop in a bubbling fluidized bed,and the jet detachment time and equivalent bubble diameter in a fluidized bed with a single jet.Subsequently,the model is used to explore the hydrodynamics of two vertical jets in a fluidized bed.The computational results reveal three flow patterns,isolated,merged and transitional jets,depending on the nozzle separation distance and jet gas velocity and influencing significantly the solid circulation pattern.The jet penetration depth is found to increase with increasing jet gas velocity,and can be predicted reasonably well by the correlations of Hang et al.(2003)for isolated jets and of Yang and Keairns(1979)for interacting jets.

  17. Analysis of microalgae pellets combustion in a circulating fluidized-bed

    Directory of Open Access Journals (Sweden)

    Kosowska-Golachowska Monika

    2017-01-01

    Full Text Available Microalgae are expected to become an important source of highvalue products with several applications in a large number of areas of biotechnology and, especially, in biofuels production. The increasing interest in microalgae as a source of biofuel (so-called third generation biofuel is due to the several advantages. The objective of this study was to investigate combustion characteristics of microalgae (Oscillatoria sp. pellets burnt in a circulating fluidized-bed (CFB in terms of sample temperature profiles, ignition time, ignition temperature, devolatilization time and the burnout time. Spherical 10-mm microalgae pellets were tested at temperature of 850°C in a 12-kW bench-scale CFB combustor.

  18. BENCH SCALE SALTSTONE PROCESS DEVELOPMENT MIXING STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Cozzi, A.; Hansen, E.

    2011-08-03

    The Savannah River National Laboratory (SRNL) was requested to develop a bench scale test facility, using a mixer, transfer pump, and transfer line to determine the impact of conveying the grout through the transfer lines to the vault on grout properties. Bench scale testing focused on the effect the transfer line has on the rheological property of the grout as it was processed through the transfer line. Rheological and other physical properties of grout samples were obtained prior to and after pumping through a transfer line. The Bench Scale Mixing Rig (BSMR) consisted of two mixing tanks, grout feed tank, transfer pump and transfer hose. The mixing tanks were used to batch the grout which was then transferred into the grout feed tank. The contents of the feed tank were then pumped through the transfer line (hose) using a progressive cavity pump. The grout flow rate and pump discharge pressure were monitored. Four sampling stations were located along the length of the transfer line at the 5, 105 and 205 feet past the transfer pump and at 305 feet, the discharge of the hose. Scaling between the full scale piping at Saltstone to bench scale testing at SRNL was performed by maintaining the same shear rate and total shear at the wall of the transfer line. The results of scaling down resulted in a shorter transfer line, a lower average velocity, the same transfer time and similar pressure drops. The condition of flow in the bench scale transfer line is laminar. The flow in the full scale pipe is in the transition region, but is more laminar than turbulent. The resulting plug in laminar flow in the bench scale results in a region of no-mixing. Hence mixing, or shearing, at the bench scale should be less than that observed in the full scale, where this plug is non existent due to the turbulent flow. The bench scale tests should be considered to be conservative due to the highly laminar condition of flow that exists. Two BSMR runs were performed. In both cases, wall

  19. Parametric experimental tests of steam gasification of pine wood in a fluidized bed reactor

    Directory of Open Access Journals (Sweden)

    L. Vecchione

    2013-09-01

    Full Text Available Among Renewable Energy Sources (RES, biomass represent one of the most common and suitable solution in order to contribute to the global energy supply and to reduce greenhouse gases (GHG emissions. The disposal of some residual biomass, as pruning from pine trees, represent a problem for agricultural and agro-industrial sectors. But if the residual biomass are used for energy production can become a resource. The most suitable energy conversion technology for the above-mentioned biomass is gasification process because the high C/N ratio and the low moisture content, obtained from the analysis. In this work a small-pilot bubbling-bed gasification plant has been designed, constructed and used in order to obtain, from the pine trees pruning, a syngas with low tar and char contents and high hydrogen content. The activities showed here are part of the activities carried out in the European 7FP UNIfHY project. In particular the aim of this work is to develop experimental test on a bench scale steam blown fluidized bed biomass gasifier. These tests will be utilized in future works for the simulations of a pilot scale steam fluidized bed gasifier (100 kWth fed with different biomass feedstock. The results of the tests include produced gas and tar composition as well gas, tar and char yield. Tests on a bench scale reactor (8 cm I.D. were carried out varying steam to biomass ratio from 0.5, 0.7 and 1 to 830°C.

  20. An assessment of water and steam reactivation of a fluidized bed spent sorbent for enhanced SO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Montagnaro, F.; Salatino, P.; Scala, F.; Chirone, R. [University of Naples Federico 2, Naples (Italy)

    2008-01-15

    Hydration-induced reactivation of spent sorbents from fluidized bed combustion has long been proven as an attractive method to achieve better sorbent exploitation so as to positively affect waste disposal, consumption of natural resources and CO{sub 2} emission issues. The present study addresses the reactivation of the sulphur capture ability of fluidized bed (FB) spent sorbent particles by either water or steam hydration. Sorbent particles are subjected to different treatments including calcination, sulphation, hydration by either water or steam, dehydration and resulphation. Processing of sorbents is accomplished by the combined use of a bench scale (40 mm ID) fluidized bed reactor (calcination, sulphation, steam hydration, dehydration and resulphation) and of a thermostated water hydrator (water hydration). Reactivation of the limestone-based sorbent is characterized in terms of hydration degree and extent/pattern of particle sulphation with a further focus on the analysis of the reactivation-induced modifications of particle microstructural/chemical properties and propensity to undergo attrition and elutriation. The effectiveness of the two processes is analyzed, with consideration on the influence of process parameters on the ultimate degree of sorbent utilization. The feasibility of sorbent reactivation is discussed in the light of the effectiveness of sorbent reactivation and of the likely operational issues associated with either process.

  1. Modeling biomass gasification in circulating fluidized beds

    Science.gov (United States)

    Miao, Qi

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

  2. 气固流化床中的信息传输%INFORMATION TRANSPORT IN GAS-SOLID FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    黄轶伦; 汪乐宇; 张卫东; 郑燕萍; 陈伯川

    2000-01-01

    The pressure fluctuation time series of gas-solid fluidized beds contains abundant information of dynamic characteristics. However, there is no accurate and reliable method to extract the embedded information due to the highly random nature of fluidization. In this work,by adopting the concept of mutual information in Shannon information theory, the authors investigate the dependence between pressure fluctuation time series in the reconstruction phase space at two different locations in the fluidized bed. The curve of mutual information indicates that there exists high-speed information transport in the fluidized bed. The average information transport speed of pressure fluctuation and its changes with gas velocity is detected by experiments. The authors argue that the information is transferred with the disturbing of particles in the beds, and the information transport speed decreases with the increasing of interspace rate.

  3. Tube erosion in bubbling fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Levy, E.K. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center; Stallings, J.W. [Electric Power Research Inst., Palo Alto, CA (United States)

    1991-12-31

    This paper reports on experimental and theoretical studies that were preformed of the interaction between bubbles and tubes and tube erosion in fluidized beds. The results are applicable to the erosion of horizontal tubes in the bottom row of a tube bundle in a bubbling bed. Cold model experimental data show that erosion is caused by the impact of bubble wakes on the tubes, with the rate of erosion increasing with the velocity of wake impact with the particle size. Wake impacts resulting from the vertical coalescence of pairs of bubbles directly beneath the tube result in particularly high rates of erosion damage. Theoretical results from a computer simulation of bubbling and erosion show very strong effects of the bed geometry and bubbling conditions on computed rates of erosion. These results show, for example, that the rate of erosion can be very sensitive to the vertical location of the bottom row of tubes with respect to the distributor.

  4. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-01-01

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

  5. Improving methane production efficiency from biomass product gas via pressurized fluidized bed system%适宜增压流化床操作参数提高生物质热气化气合成甲烷效率

    Institute of Scientific and Technical Information of China (English)

    冯飞; 沈来宏; 肖军; 吕潇

    2015-01-01

    Natural gas is one of the clean primary energy sources and high-quality chemical raw materials. Technology of methane production from biomass thermo-chemical gasification (biomass-to-SNG) is one of the most important pathways to produce synthetic natural gas (SNG) to substitute diminishing natural gas. In the biomass-to-SNG process, the biomass is first converted into product gas through biomass gasification. Then, the product gas full of CO and H2is synthesized into methane through the methanation processes after some proper cleaning and conditioning processes. Finally, the crude synthetic natural gas is upgraded with CO2 removal and gas dehydration. In the whole biomass-to-SNG process, the methanation process of product gas is a key step. A pressurized fluidized bed methanation reactor system was designed and constructed, which is mainly composed of a main reactor and auxiliary equipments. An experimental study of methane production from product gas was carried out on this methantion reactor system with the commercial methanation catalyst as bed material. The Energy Dispersive Spectrometer analysis indicates that the methanation catalyst contains high nickel content and was squashed into small particles for the study. Then, the effects of methanation temperature, pressure, space velocity, and ratio of H2 to CO on the performance indexes (i.e. methane formation rate and CO conversion rate) were investigated. The results show that methane is efficiently produced on this pressurized fluidized bed methanation reactor system and the typical methane formation rate is higher than 3.2 mol/(L·h) while the CO conversion rate is more than 80%. Higher methanation temperature is favored to the methanation process and the methane formation rate and CO conversion rate achieve the maximum values at the methanation temperature about 350℃. However, when the methanation temperature is higher than 350℃, the methane formation rate and CO conversion rate decline slowly since the

  6. Pulsed atmospheric fluidized bed combustion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

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

  7. Kinetics of Reduction Reaction in Micro-Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    LINYin-he; GUOZhan—cheng; TANGHui—qing; REN Shan; LIJing—wei

    2012-01-01

    Micro-fluidized bed reactor is a new research method for the reduction of iron ore fines. The reactor is op- erated as a differential reactor to ensure a constant gas concentration and temperature within the reactor volume. In order to understand the dynamic process of the reduction reaction in micro-fluidized bed, a series of kinetic experi- ments were designed. In the micro fluidized bed, the use of shrinking core model describes the dynamic behavior of reduction of iron ore. And the apparent activation energy is calculated in the range of 700--850 ~C while the initial atmosphere is 100% content of CO.

  8. Development of an enzyme fluidized bed reactor equipped with static mixers: application to lactose hydrolysis in whey

    Energy Technology Data Exchange (ETDEWEB)

    Fauquex, P.F.; Flaschel, E.; Renken, A.

    1984-01-01

    Reactor operation with immobilized enzymes in fixed bed arrangement is often impaired due to the presence of finely divided solid matter, adsorbing substances or gas. The fluidized bed reactor would be applied in such cases owing to a limited pressure drop, a controlled voidage, and the avoidance of perforated plates for catalyst retention. Since enzymic reactions are often slow processes, catalysts of high external surface area should be provided together with sufficient time. However, classical fluidized beds suffer from hydrodynamic instability under these conditions. Therefore, a new reactor design was developed which used motionless mixers as internals. Fluidized bed reactors equipped with internals exhibit an outstanding hydrodynamic stability accompanied by an increase of the operating range in terms of flow rate by a factor of 4 compared to the classical fluidized bed. Results are presented, with emphasis on the backmixing and expansion characteristics. Various motionless mixers were investigated in columns of 39 and 150 mm in diameter. The fluidized bed equipped with internals was used for lactose hydrolysis in partially deproteinized whey. The lactase from Aspergillus niger immobilized on silica gel particles of 125-160 molm had a half-life of approximately 1 mo.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-03-01

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

  11. Bench-scale demonstration of hot-gas desulfurization technology. Quarterly report, January 1--March 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    At the start of the current project, the DSRP (Direct Sulfur Recovery Process) technology was at the bench-scale development stage with a skid-mounted system ready for field testing. The process had been extended to fluidized-bed operation in the Stage 1 reactor. A preliminary economic study for a 100 MW plant in which the two-stage DSRP was compared to conventional processes indicated the economic attractiveness of the DSRP. Through bench-scale development, both fluidized-bed zinc titanate and DSRP technologies have been shown to be technically and economically attractive. The demonstrations prior to the start of this project, however, had only been conducted using simulated (rather than real) coal gas and simulated regeneration off-gas. Thus, the effect of trace contaminants in real coal gases on the sorbent and DSRP catalyst was not known. Also, the zinc titanate desulfurization unit and DSRP had not been demonstrated in an integrated manner. The overall goal of this project is to continue further development of the zinc titanate desulfurization and DSRP technologies by scale-up and field testing (with actual coal gas) of the zinc titanate fluidized-bed reactor system, and the Direct Sulfur Recovery Process.

  12. Synthesis of a nanosilica supported CO{sub 2} sorbent in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Soria-Hoyo, C., E-mail: cshoyo@us.es [Facultad de Física, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla (Spain); Valverde, J.M. [Facultad de Física, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla (Spain); Ommen, J.R. van [Department of Chemical Engineering, Delft University of Technology, Product and Process Engineering, Julianalaan 136, 2628 BL Delft (Netherlands); Sánchez-Jiménez, P.E.; Pérez-Maqueda, L.A.; Sayagués, M.J. [Instituto de Ciencia de Materiales (CSIC – Universidad de Sevilla), Americo Vespucio 49, 41092 Sevilla (Spain)

    2015-02-15

    Highlights: • CaO coating at atmospheric pressure is applied on silica nanoparticles in a fluidized bed. • Atmospheric pressure would facilitate scaling-up of the process. • The conditions for the coating process at atmospheric pressure are discussed. • The CO{sub 2} sorbent capacity is demonstrated by TGA in carbonation/calcination. • STEM-EDX shows the presence of CaO on the surface of the nanoparticles. - Abstract: CaO has been deposited on a nanosilica powder matrix by a procedure based on atomic layer deposition (ALD) in a fluidized bed reactor at atmospheric pressure following a potentially scalable process. In previous works ALD in gas fluidized bed has been mostly performed under reduced pressure, which hampers scaling-up the production technology. The material synthesized in the present work is tested as CO{sub 2} solid sorbent at calcium looping conditions. Multicyclic thermogravimetric analysis (TGA) shows that the nanosilica support stabilizes the capture capacity of CaO. EDX-STEM analysis illustrates the presence of Ca well distributed on the surface of the SiO{sub 2} nanoparticles.

  13. RESEARCH ON DENSITY STABILITY OF AIR DENSE MEDIUM FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    骆振福; 陈清如

    1994-01-01

    In this papcr on thc basis of studying the distribution of fine coal in the dense medium fluidized bed, the optimal size range of fine coal, which constitutes a fluidized bed together with the dense medium, has been found. In the separating process the fine coal will continuously accumulate in fluidized bed, thus inevitably reducing the density of the bed. In order to keep bed density stable, the authors adopted such measures as split-flow of used medium and complement of fresh dense medium. The experiment results in both lab and pilot systems of the air-dense medium fluidized bed show that these measures are effective and satisfactory. Then authors also have established some relative dynamic mathematical models for it.

  14. Flow boiling heat transfer in circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    Xiaoguang REN; Jiangdong ZHENG; Sefiane KHELLII; Arumemi-Ikhide MICHAEL

    2009-01-01

    In order to enhance heat transfer and mitigate contamination in the boiling processes, a new type of vapor-liquid-solid (3-phase) circulating fluidized bed boil-ing system has been designed, combining a circulating fluidized bed with boiling heat transfer. Experimental results show an enhancement of the boiling curve. Flow visualization studies concerning flow hydrodynamics within the riser column are also conducted whose results are presented and discussed.

  15. Fluidized Bed Air-to-Air Heat Pump Evaporator Evaluation.

    Science.gov (United States)

    1983-07-01

    Frost formation of air-to-air heat pump evaporator surfaces reduces unit efficiency and restricts application. The use of a fluidized bed heat...exchanger as an air-to- heat pump evaporator was investigated to determine if frost accumulation could be eliminated. Experimental investigations were...evaluated, with no practical solution being developed. The use of a fluidized bed heat exchanger for air-to-air heat pump evaporators was determined not feasible. (Author)

  16. Collecting aerosol in airflow with a magnetically stabilized fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A magnetically stabilized fluidized bed (MSB) is a highly efficient filter that takes the advantage of both fluidized beds and fixed beds. This paper presents the research to collect aerosol in airflow with a MSB. The filtering model of MSB is established with its parameters including magnetic field intensity,gas superficial velocity, average grain-size, and bed height on thecollection efficiency of MSB. The model is verified by experiments.

  17. Chebyshev super spectral viscosity method for a fluidized bed model

    CERN Document Server

    Sarra, S A

    2003-01-01

    A Chebyshev super spectral viscosity method and operator splitting are used to solve a hyperbolic system of conservation laws with a source term modeling a fluidized bed. The fluidized bed displays a slugging behavior which corresponds to shocks in the solution. A modified Gegenbauer postprocessing procedure is used to obtain a solution which is free of oscillations caused by the Gibbs-Wilbraham phenomenon in the spectral viscosity solution. Conservation is maintained by working with unphysical negative particle concentrations.

  18. Fluidized-bed calciner with combustion nozzle and shroud

    Science.gov (United States)

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

    1977-01-01

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

  19. Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Gamwo, I.K.; Miller, A.; Gidaspow, D.

    1992-04-01

    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Spectral analysis of CFB data obtained at Illinois Institute of Technology shows that the frequencies of pressure oscillations are less than 0.1 Hertz and that they increase with solids volume fraction to the usual value of one Hertz obtained in bubbling beds. These data are consistent with the kinetic theory interpretation of density wave propagation.

  20. 气-液-固自然循环流化床中的流动特性和压降%Flow Properties and Pressure Drop of Gas-Liquid-Solid Natural Circulating in Fluidized-Bed

    Institute of Scientific and Technical Information of China (English)

    齐国鹏; 姜峰; 赵燕禹; 赵国华; 周震; 李修伦

    2009-01-01

    A fluidized-bed evaporator for gas-liquid-solid natural circulation was set up to research the flow and distribution of solid particles and pressure drop of liquid-solid two-phase flow in a heating pipe bundle. With CCD image collecting and processing system,the influences of the particle kinds,particle holdup and additive air amount were studied. The experimental results show that air inlet positions have much effect on the distribution of solid particles in the heating pipe bundle. The form of moving and fluidization of solid particles in up-channel is different from that in down-channel. In up-channel,solid particles make circulating movement with the central part rising and perimeter dropping. As the density decreases,the distribution of solid particles in up-channel gradually becomes uniform. In down-channel,solid particles form two big whirls at both sides of the central axis. As additive air amount increases,the rotation rate of whirls increases. When the air is input from the up-channel,the pressure drop of liquid-solid two-phase flow in the heating pipe bundle increases with the increase of particles holdup and air amount. The pressure drop model of liquid-solid two-phase flow in the heating pipe bundle has been set up,and the calculated data agree well with the experimental results.%建立了气-液-固冷模多管自然循环流化床蒸发器,利用CCD图像采集和处理系统,研究了固体颗粒的种类、含率和通气量等操作参数对于固体颗粒的流化和运动形态、分布以及加热管束中液-固两相流压降的影响.结果表明:通气位置对于固体颗粒在加热管束中的分布影响较大.在上、下管箱中,固体颗粒的运动和流化形态不同.在上管箱中,固体颗粒形成中心上升、四周下降的循环运动,并且随着其密度的降低,固体颗粒在上管箱中的分布逐渐趋向均匀;在下管箱中,固体颗粒在中心轴的两侧形成两个大的旋涡,旋涡的旋转速度随着

  1. Fluidized-bed pyrolysis of waste bamboo

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Bamboo was a popular material substituting for wood, especially for one-off commodity in China. In order to recover energy and materials from waste bamboo, the basic characteristics of bamboo pyrolysis were studied by a thermogravimetric analyzer. It implied that the reaction began at 190~210 ℃, and the percentage of solid product deceased from about 25% to 17% when temperature ranged from 400 ℃ to 700 ℃. A lab-scale fluidized-bed furnace was setup to research the detailed properties of gaseous, liquid and solid products respectively. When temperature increased from 400 ℃ to 700 ℃, the mass percent of solid product decreased from 27% to 17% approximately, while that of syngas rose up from 19% to 35%. When temperature was about 500℃, the percentage of tar reached the top, about 31%. The mass balance of these experiments was about 93%~95%. It indicated that three reactions involved in the process: pyrolysis of exterior bamboo, pyrolysis of interior bamboo and secondary pyrolysis of heavy tar.

  2. Development of a bioreactor based on magnetically stabilized fluidized bed for bioartificial liver.

    Science.gov (United States)

    Deng, Fei; Chen, Li; Zhang, Ying; Zhao, Shan; Wang, Yu; Li, Na; Li, Shen; Guo, Xin; Ma, Xiaojun

    2015-12-01

    Bioartificial liver (BAL) based on microcapsules has been proposed as a potential treatment for acute liver failure. The bioreactors used in such BAL are usually expected to achieve sufficient flow rate and minimized void volume for effective application. Due to the superiorities in bed pressure drop and operation velocity, magnetically stabilized fluidized beds (MSFBs) show the potential to serve as ideal microcapsule-based bioreactors. In the present study, we attempted to develop a microcapsule-based MSFB bioreactor for bioartificial liver device. Compared to conventional-fluidized bed bioreactors, the bioreactor presented here increased perfusion velocity and decreased void volume significantly. Meanwhile, the mechanical stability as well as the immunoisolation property of magnetite microcapsules were well maintained during the fluidization. Besides, the magnetite microcapsules were found no toxicity to cell survival. Therefore, our study might provide a novel approach for the design of microcapsule-based bioartificial liver bioreactors.

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-08-01

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

  4. Flow Pattern in a Fluidized Bed with a Non-fluidized Zone

    DEFF Research Database (Denmark)

    Lin, Weigang; Dam-Johansen, Kim; Van den Bleek, Cor. M.

    1997-01-01

    The flow pattern of a fluidized bed with non-fluidized zones is investigated both experimentally and theoretically. Experiments were carried out in such a way that air was introduced only through part of the distributor. The results show a significant amount of air flowing to the zone where no air...... is introduced. However, once the gas velocity exceeds the minimum fluidization velocity in the zone where the air is introduced, the cross-flow hardly changes upon further increase of the gas velocity. A continuity equation and Ergun's equation are used to describe the flow pattern and pressure distribution...... over the bed. Very good agreement between the experimental and calculated results is achieved without any fitting parameter. The results are relevant to the understanding of heat transfer behaviour of a fluidized bed combustor (FBC) that is only partly fluidized to control its load....

  5. Bed dynamics of gas-solid fluidized bed with rod promoter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The dynamic characteristics of a gas-solid fluidized bed with different rod promoters have been investigated in terms of bed expansion and fluctuation, minimum fluidization velocity and distributor-to-bed pressure drop ratio at minimum fluidization velocity. Experimentation based on statistical design has been carried out and model equations using factorial design of experiments have been developed for the above mentioned quantities for a promoted gas-solid fluidized bed. The model equations have been tested with additional experimental data. The system variables include four types of rod promoters of varying blockage volume, bed particles of four sizes and four initial static bed heights. A comparison between the predicted values of the output variables using the proposed model equation with their corresponding experimental ones shows fairly good agreement.

  6. Dimensional similitude and the hydrodynamics of three- phase fluidized beds

    Science.gov (United States)

    Safoniuk, Michael

    It is proposed that scaling of three-phase fluidized bed hydrodynamics can be carried out based on geometric similarity and matching of a set of five dimensionless groups: (i)the M-group, M = g.Δρ.μ L4/(ρL2.σ 3); (ii)an Eötvös number, Eo = g.Δρ.d p2/σ (iii)the liquid Reynolds number, Re L = ρL.dp.UL/μ L; (iv)a density ratio, βd = ρp/ρ L; and (v)a superficial velocity ratio, βu = U g/UL. These were varied in an experimental study where four dimensionless hydrodynamic parameters were measured: (i)gas hold-up, ɛ g; (ii)bed expansion ratio, βbe (iii)the ratio of mean bubble diameter to particle diameter, db/dp ; and (iv)the ratio of mean bubble rise velocity to gas superficial velocity, Ub/Ug. This approach was validated experimentally by matching the dimensionless operating conditions from a kerosene-nitrogen-ceramic three-phase system with those in an aqueous magnesium sulphate solution-air-aluminum particle fluidized bed. There was good agreement between the gas hold-ups and bed expansion ratios in the two systems. A pilot-plant scale cold-flow co-current upwards-flowing three-phase fluidized bed column of inside diameter 292 mm was built and operated using three different liquids (tap water, an aqueous 44 mass % glycerol solution, and an aqueous 60 mass % glycerol solution), air, and cylindrical aluminum particles of diameter 4 mm and length 10 mm. The fluids and solids were carefully selected to result in dimensionless group values in the range of those of an industrial hydroprocessor. Specially built conductivity probes and pressure transducers were used to measure the hydrodynamic properties for different gas and liquid superficial velocities. Special attention was required to provide for drift and calibration when recording and analyzing data from the conductivity probes. Gas hold-ups were in the range of 5 to 20% by volume and were correlated as a function of liquid-phase Reynolds number and superficial velocity ratio. The gas hold-ups were a

  7. Fluidization Characteristics of a Prototype Fluidized Bed Reactor

    Directory of Open Access Journals (Sweden)

    F. ABERUAGBA

    2005-01-01

    Full Text Available The fluidization characteristics of a prototype-fluidized bed laboratory reactor were understudied in order to investigate the suitable conditions at which the dehydrogenation reaction of butane could be carried out. To achieve this, a reactor with an effective volume of 1100ml was fabricated and coupled with temperature and pressure accessories.Zeolites were obtained from the market and clay obtained from different sources and pre-treated was used as catalyst. Airflow at high velocity between 3000-7000ml/hr was used as the fluidising medium to obtain the bed characteristics while butane gas was used to obtain the dehydrogenation kinetics.The temperature of the reactor system was varied between 353K and 413K while maintaining constant pressure of 1.5 105 N/m2 through a manifold gauge and a constant catalyst weight. Various methods such as pressure fluctuations, visual observations, and bed expansion were used to determine the transition velocity at which fluidization begins. It was observed that this depends on factors such as mean particle size, particle size distribution, and column diameter.The minimum fluidizing velocity obtained for zeolite was 0.0133m/s and 0.0102m/s for treated clay materials both for a particle size of 250μm. The conversion of butane over the catalysts showed an increase in both cases with a maximum at 0.9813 at 413K. This decreases as the reaction progresses.

  8. INVESTIGATION INTO MALDISTRIBUTION IN A CIRCULATING FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Qingjie Guo; Joachim Werther; Ernst-Ulrich Hartge

    2003-01-01

    Experiments on maldistribution were conducted in a 8.5 m high, 1 m ×0.3 m cross-section circulating fluidized bed equipped with a 33 bubble-cap distributor. There exists an uneven distribution in flow rate, the bubble caps in the center region having larger flow rates than those next to the wall. Flow resistance has been found to be the dominating factor influencing gas flow rate distribution. Increasing superficial gas velocity improves flow rate distribution for a low pressure-drop distributor. For a high pressure-drop distributor, superficial gas velocity has little effect on flow rate distribution. A ratio of maximum flow rate through a bubble cap to average flow rate through all bubble caps (Vmax/Vav) characterizes the flow rate distribution. Distributor-to-bed pressure drop ratio (△Pd/△Pr) is another necessary parameter to achieve even flow distribution. A correlation between these two ratios is developed for predicting flow rate maldi stribution in CFB bubble-cap distributor.

  9. INVESTIGATION OF FUEL CHEMISTRY AND BED PERFORMANCE IN A FLUIDIZED BED BLACK LIQUOR STEAM REFORMER

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Whitty

    2003-12-01

    The University of Utah project ''Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer'' (DOE award number DE-FC26-02NT41490) was developed in response to a solicitation for projects to provide technical support for black liquor and biomass gasification. The primary focus of the project is to provide support for a DOE-sponsored demonstration of MTCI's black liquor steam reforming technology at Georgia-Pacific's paper mill in Big Island, Virginia. A more overarching goal is to improve the understanding of phenomena that take place during low temperature black liquor gasification. This is achieved through five complementary technical tasks: (1) construction of a fluidized bed black liquor gasification test system, (2) investigation of bed performance, (3) evaluation of product gas quality, (4) black liquor conversion analysis and modeling and (5) computational modeling of the Big Island gasifier. Four experimental devices have been constructed under this project. The largest facility, which is the heart of the experimental effort, is a pressurized fluidized bed gasification test system. The system is designed to be able to reproduce conditions near the black liquor injectors in the Big Island steam reformer, so the behavior of black liquor pyrolysis and char gasification can be quantified in a representative environment. The gasification test system comprises five subsystems: steam generation and superheating, black liquor feed, fluidized bed reactor, afterburner for syngas combustion and a flue gas cooler/condenser. The three-story system is located at University of Utah's Industrial Combustion and Gasification Research Facility, and all resources there are available to support the research.

  10. The Physical Models of Cyclone Diplegs in Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    K.Smolders; D.Geldart; J.Baeyens

    2001-01-01

    In most industrial fluidization units, two- or three-stage cyclone systems are used to clean the product gases. To return the solids to the bed, these cyclones are fitted with diplegs. By pass of gas from the bed through the dipleg is partially overcome by the back pressure build-up in the dipleg and by adding a trickle valve at the bottom of the dipleg. Diplegs of primary cyclones, operating at a high solid loading behave differently from diplegs of secondary and tertiary cyclones which operate at low solid loading. Both types have been investigated by pressure drop measurements, visual observation and by measurements of the air flow rate flowing up the riser. The primary dipleg was also studied using electrical capacitance tomography. The results are reported hereafter and will give a first indication towards the right design of the dipleg and the selection of the trickle valve. The influence of gas flow in the dipleg on the conversion in a catalytic fluidized bed reactor is found to be negligible.

  11. Bubble dynamics in a two-dimensional gas-solid fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Related referential studies on gas-solid two-phase flows were briefly reviewed. Bubble ascending in a two-dimensional (2D) gas-solid fluidized bed was studied both experimentally and numerically. A modified continuum model expressed in the conservation form was used in numerical simulation. Solid-phase pressure was modeled via local sound speed; gas-phase turbulence was described by the K-ε two-equation model. The modified implicit multiphase formulation (IMF) scheme was used to solve the model equations in 2D Cartesian/cylindrical coordinates. The bubble ascending velocity and particle motion in the 2D fluidized bed were measured using the photochromic dye activation (PDA) technique, which was based on UV light activation of particles impregnated with the dye. Effects of bed height and superficial gas velocity on bubble formation and ascent were investigated numerically. The numerically obtained bubble ascending velocities were compared with experimental measurements. Gas bubble in jetting gas-solids fluidized bed was also simulated numerically.

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

    Science.gov (United States)

    Sun, Jingyuan; Yan, Yong

    2016-11-01

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

  13. FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2006-12-22

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

  14. Fluidized bed gasification of industrial solid recovered fuels.

    Science.gov (United States)

    Arena, Umberto; Di Gregorio, Fabrizio

    2016-04-01

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

  15. Fluidized bed combustion of pesticide-manufacture liquid wastes

    Directory of Open Access Journals (Sweden)

    SAŠA MILETIĆ

    2010-04-01

    Full Text Available Industrial liquid wastes can be in the form of solutions, suspensions, sludges, scums or waste oil and have organic properties. The objective of this work was to demonstrate the technical feasibility of a fluidized bed as a clean technology for burning liquid waste from a pesticide production plant. The combustion of liquid waste mixtures, obtained from realistic samples, was investigated in a pilot scale fluidized bed with quartz sand particles of 0.63–1.25 mm in diameter and 2610 kg/m3 in density at 800–950 °C. To ensure complete combustion of liquid waste and additional fuel, the combustion chamber was supplied with excess air and the U/UmF (at ambient temperature was in between 1.1 and 2.3. In the fluidized bed chamber, liquid waste, additional liquid fuel and air can be brought into intense contact sufficient to permit combustion in bed without backfire problems. The experimental results show that the fluidized bed furnace offers excellent thermal uniformity and temperature control. The results of the combustion tests showed that degradation of liquid wastes can be successfully realized in a fluidized bed with no harmful gaseous emissions by ensuring that the temperatures of both the bed and the freeboard are not lower than 900 °C.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mazac, V. [Energoprojekt Praha, Ostrava (Czechoslovakia); Novacek, A. [Moravskoslezske teplamy, Ostrava (Czechoslovakia); Volny, J. [Templamy Karvina (Czechoslovakia)

    1995-12-01

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

  17. Modeling of sulfur oxide removal in circulating fluidized bed absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Mao, D.; Edwards, J.R.; Kuznetsov, A.V. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Mechanical and Aerospace Engineering; Srivastava, R. [U.S. Environmental Protection Agency, Research Triangle Park, NC (United States). Air Pollution Prevention and Control Division

    2002-07-01

    This paper presents a model to simulate a circulating fluidized bed absorber (CFBA) that combines flow, mixing, and reaction through residence time distribution (RTD). These parameters are often overlooked in existing simulation models. In addition, the paper presents a newly developed gas-solid reaction model for sulphur dioxide removal by limestone. For the reaction model that considers RTD inside the core and annulus regions of CFBA, the macrochemical reaction is simulated according to microchemical reaction dynamics. The proposed model can predict sulphur dioxide and limestone distributions inside the CFBA and calculate how much limestone is needed to remove an appropriate amount of sulphur dioxide. Sulphur dioxide concentration at the outlet of the CFBA decreases as the distance of the CFBA increases from the bottom of the core region. Limestone concentration varies only very slightly in the core region, suggesting that limestone in the CFBA is efficiently utilized to remove sulphur oxide. Sulphur dioxide partial pressure at the exit of the CFBA decreases as fresh limestone increases at the inlet to the CFBA. 16 refs., 8 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-01-01

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

  19. Characteristics of oily sludge combustion in circulating fluidized beds.

    Science.gov (United States)

    Zhou, Lingsheng; Jiang, Xiumin; Liu, Jianguo

    2009-10-15

    Incineration of oily sludge in circulating fluidized beds may be an effective way for its management in some cases. The objective of the present paper is to investigate combustion characteristics of oily sludge, which would be helpful and useful for the design and simulation of a circulating fluidized bed. Firstly, the pyrolysis and combustion of oily sludge were studied through some thermal analyses, which included the thermogravimetric (TG) analysis and the differential thermal analytical (DTA) analysis. It was found that the combustion of oily sludge might be the combustion of its pyrolysis products. Secondly, an experiment for measuring of main components of the volatile from oily sludge pyrolysis was carried out. Some mathematic correlations about the compositions of volatile from oily sludge devolatilization were achieved from the experimental results. Finally, the combustion characteristics of oily sludge was studied in a lab-scale circulating fluidized bed, which could obtain some information about the location of release and combustion of the volatiles.

  20. Developments in fluidized bed conversion of solid fuels

    Directory of Open Access Journals (Sweden)

    Leckner Bo

    2016-01-01

    Full Text Available A summary is given on the development of fluidized bed conversion (combustion and gasification of solid fuels. First, gasification is mentioned, following the line of development from the Winkler gasifier to recent designs. The combustors were initially bubbling beds, which were found unsuitable for combustion of coal because of various drawbacks, but they proved more useful for biomass where these drawbacks were absent. Instead, circulating fluidized bed boilers became the most important coal converters, whose design now is quite mature, and presently the increments in size and efficiency are the most important development tasks. The new modifications of these conversion devices are related to CO2 capture. Proposed methods with this purpose, involving fluidized bed, are single-reactor systems like oxy-fuel combustion, and dual-reactor systems, including also indirect biomass gasifiers.

  1. Understanding and predicting bed humidity in fluidized bed granulation.

    Science.gov (United States)

    Hu, Xinhui; Cunningham, John; Winstead, Denita

    2008-04-01

    Bed humidity is a critical parameter that needs to be controlled in a fluidized bed granulation to ensure reliability. To predict and control the bed humidity during the fluidized bed granulation process, a simple model based on the mass conservation of moisture was developed. The moisture mass balance model quantitatively simulates the effects of spray rate, binder solution concentration, airflow rate, inlet air temperature, and dew point on the bed humidity. The model was validated by a series of granulations performed in different scale granulators including Glatt GPCG-1, GPCG-15, and GPCG-60. Good agreement was observed between the theoretical prediction and the measured loss on drying (LOD). The model developed in the current work enables us to choose the appropriate parameters for the fluidized bed granulation and can be used as a valuable tool in process scaling-up.

  2. MODELING NONLINEAR DYNAMICS OF CIRCULATING FLUIDIZED BEDS USING NEURAL NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Wei; Chen; Atsushi; Tsutsumi; Haiyan; Lin; Kentaro; Otawara

    2005-01-01

    In the present work, artificial neural networks (ANNs) were proposed to model nonlinear dynamic behaviors of local voidage fluctuations induced by highly turbulent interactions between the gas and solid phases in circulating fluidized beds. The fluctuations of local voidage were measured by using an optical transmittance probe at various axial and radial positions in a circulating fluidized bed with a riser of 0.10 m in inner diameter and 10 m in height. The ANNs trained with experimental time series were applied to make short-term and long-term predictions of dynamic characteristics in the circulating fluidized bed. An early stop approach was adopted to enhance the long-term prediction capability of ANNs. The performance of the trained ANN was evaluated in terms of time-averaged characteristics, power spectra, cycle number and short-term predictability analysis of time series measured and predicted by the model.

  3. Combustion in fluidized bed reactors; Verbrennung in Wirbelschichtreaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Thome-Kozmiensky, Karl J. [vivis CONSULT GmbH, Nietwerder (Germany)

    2013-03-01

    Since the first application for the coal gasification, the fluidized bed technology has passed an impressive development. Nowadays, the fluidized bed technology is utilized at chemical processes, drying and cooling, gasification, combustion and purification of exhaust gas. In the firing technology, the fluidized technology initially has been proved in the combustion of very high ash coal and sewage sludge. Recently, the fluidized bed technology also is applied in the drying of sewage sludge, combustion of domestic waste - as in Japan and Sweden - as well as in the gasification and combustion of substitute fuels, biomass - wood pellets, wood chips, straw, cocoa shells and so forth - and residues from the paper manufacturing - such as in Germany and Austria. Under this aspect, the author of the contribution under consideration reports on the combustion of sewage sludge, substitute fuels and biomass.

  4. ELECTROSTATIC PHENOMENA IN GAS-SOLIDS FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    Hsiaotao T. Bi

    2005-01-01

    Electrostatic charges are generated by particle-wall, particle-particle and particle-gas contacts in gas-solids transport lines and fluidized bed reactors. High particle charge densities can lead to particle agglomeration,particle segregation, fouling of reactor walls and internals, leading to undesirable by-product and premature shut-down of processing equipment. In this paper, the charge generation, dissipation and segregation mechanisms are examined based on literature data and recent experimental findings in our laboratory. The particle-wall contact charging is found to be the dominant charge generation mechanism for gas-solids pneumatic transport lines, while bipolar charging due to intimate particle-particle contact is believed to be the dominant charge generation mechanism in gas fluidized beds. Such a bipolar charging mechanism is also supported by the segregation patterns of charged particles in fluidized beds in which highly charged particles tend to concentrate in the bubble wake and drift region behind rising bubbles.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rokkam, Ram [Iowa State Univ., Ames, IA (United States)

    2012-01-01

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

  6. DRYING OF GRANULAR MATERIALS IN AGITATED FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An experimental study of the drying characteristics of an agitated fluidized bed dryer is presented and discussed. In the study, the citric acid particles were used as bed material with the diameters ranging from 0.2mm to 1.3mm. The variables affecting apparently the drying rate were found to be the mass flow rate, the inlet air temperature, the rotary speed of agitating mechanism and the particles feed rate. Comparing with other variables considered, mass flow rate was found to have the least important influence on the drying rate. The agitated fluidized bed dryer is suitable to drying agglomerating or sticky materials.

  7. Atmospheric fluidized bed coal combustion research, development and application

    CERN Document Server

    Valk, M

    1994-01-01

    The use of fluidized bed coal combustion technology has been developed in the past decade in The Netherlands with a view to expanding the industrial use of coal as an energy supply. Various research groups from universities, institutes for applied science and from boiler industries participated and contributed to this research area. Comprehensive results of such recent experimentation and development work on atmospheric fluidized bed combustion of coal are covered in this volume. Each chapter, written by an expert, treats one specific subject and gives both the theoretical background as well a

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

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, R.Q.

    1989-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan

    2013-06-30

    One of the largest challenges for 21st century is to fulfill global energy demand while also reducing detrimental impacts of energy generation and use on the environment. Gasification is a promising technology to meet the requirement of reduced emissions without compromising performance. Coal gasification is not an incinerating process; rather than burning coal completely a partial combustion takes place in the presence of steam and limited amounts of oxygen. In this controlled environment, a chemical reaction takes place to produce a mixture of clean synthetic gas. Gas-solid fluidized bed is one such type of gasification technology. During gasification, the mixing behavior of solid (coal) and gas and their flow patterns can be very complicated to understand. Many attempts have taken place in laboratory scale to understand bed hydrodynamics with spherical particles though in actual applications with coal, the particles are non-spherical. This issue drove the documented attempt presented here to investigate fluidized bed behavior using different ranges of non-spherical particles, as well as spherical. For this investigation, various parameters are controlled that included particle size, bed height, bed diameter and particle shape. Particles ranged from 355 µm to 1180 µm, bed diameter varied from 2 cm to 7 cm, two fluidized beds with diameters of 3.4 cm and 12.4 cm, for the spherical and non-spherical shaped particles that were taken into consideration. Pressure drop was measured with increasing superficial gas velocity. The velocity required in order to start to fluidize the particle is called the minimum fluidization velocity, which is one of the most important parameters to design and optimize within a gas-solid fluidized bed. This minimum fluidization velocity was monitored during investigation while observing variables factors and their effect on this velocity. From our investigation, it has been found that minimum fluidization velocity is independent of bed

  10. Development of a fluidized bed system for adsorption of phenol from aqueous solutions with commercial macroporous resins

    Directory of Open Access Journals (Sweden)

    R. A. Corrêa

    2007-03-01

    Full Text Available This work is related to removal of phenol from wastewaters by adsorption onto polymeric resins, a current alternative to activated carbon. A closed circuit, bench-scale liquid fluidized bed system was developed for this purpose. Phenol aqueous solutions with initial concentrations in the range of 0.084 to 0.451 kg/m³ were used to fluidize small permeable capsules of stainless steel screen containing a commercial resin at 308 K. Experiments were carried out using a fluidizing velocity 20% above that of the minimum fluidization of the capsules. Typically, 30 passages of the liquid volume circulating through the bed were required to reach a quasi-equilibrium concentration of phenol in the treated effluent. A simple batch adsorption model using the Freundlich isotherm successfully predicted final phenol concentrations. Suspended solids, often present in residual waters and a common cause of fixed bed clogging, were simulated with wood sawdust.

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

    Science.gov (United States)

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

    2010-05-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesan, Arjun K.; Sharbatmaleki, Mohamadali [Department of Civil and Environmental Engineering, University of Nevada Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, NV 89154-4015 (United States); Batista, Jacimaria R., E-mail: jaci@ce.unlv.edu [Department of Civil and Environmental Engineering, University of Nevada Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, NV 89154-4015 (United States)

    2010-05-15

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

  13. Principles of a novel multistage circulating fluidized bed reactor for biomass gasification

    NARCIS (Netherlands)

    Kersten, Sascha R.A.; Prins, Wolter; Drift, van der Bram; Swaaij, van Wim P.M.

    2003-01-01

    In this paper a novel multistage circulating fluidized bed reactor has been introduced. The riser of this multistage circulating fluidized bed consists of several segments (seven in the base-case design) in series each built-up out of two opposite cones. Due to the specific shape, a fluidized bed ar

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

    Science.gov (United States)

    Snell, George J.; Kydd, Paul H.

    1983-01-01

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

  15. Fluidization of potato starch in a stirred vibrating fluidized bed

    NARCIS (Netherlands)

    Kuipers, N.J M; Stamhuis, Eize; Beenackers, A.A C M

    1996-01-01

    A novel gas-solid reactor for cohesive C-powders such as potato starch is introduced, designed and characterized, the so-called stirred vibrating fluidized bed. The effects of a sinusoidal vibration of the gas distributor and/or stirring of the bed are investigated. The fluidization index, bed expan

  16. Particle transport in fluidized beds : experiments and stochastic models

    NARCIS (Netherlands)

    Dechsiri, Chutima

    2004-01-01

    Fluidization is a process in which solids are caused to behave like fluid by blowing gas or liquid upwards through the solid-filled reactor. The behavior of a bed of particles within the reactor during the process is very complex and difficult to predict. To make sure that a fluidized bed reactor is

  17. DEVELOPMENT POTENTIALS AND RESEARCH NEEDS IN CIRCULATING FLUIDIZED BED COMBUSTION

    Institute of Scientific and Technical Information of China (English)

    Lothar Reh

    2003-01-01

    First a report about present status of circulating fluidized bed reactors for coal and multi-fuel combustion in power plants is given. Thereafter the development potentials and research needs for further improvement of CFB combustors operating with finely grained bed materials are discussed and recommendations for direction of further research and development work are presented.

  18. Propylene polymerization in a circulating slugging fluidized bed reactor

    NARCIS (Netherlands)

    Putten, van Inge Cornelia

    2004-01-01

    The work presented in this thesis is concerned with research on the riser of a circulating fluidized bed system for olefin polymerization. In the riser section, fluidization takes place in the transporting slugging mode and polymer particles are produced in the riser in a non-isothermal way. Propert

  19. Agglomeration in a fluidized bed using multiple jet streams

    Energy Technology Data Exchange (ETDEWEB)

    Rehmat, A.; Abbasian, J. (Institute of Gas Technology, Chicago, IL (United States)); Kothari, M.; Hariri, H.; Arastoopour, H. (Illinois Inst. of Tech., Chicago, IL (United States))

    1992-01-01

    Tests were conducted to determine the overall temperature distribution, temperature in the vicinity of the jets, and the rate of agglomeration in a fluidized bed containing multiple jet streams. Agglomeration of ash during coal gasification increases carbon utilization efficiency considerably. The agglomeration requires a fluidized-bed reactor with a specially designed distributor equipped with a jet to yield a hot zone confined within the bed. The rate of agglomeration depends upon the size and the intensity of the zone. This rate, and hence the unit capacity, could be increased by adding multiple jets to the distributor. The purpose of this study was to verify this phenomenon. The temperature distribution inside the agglomerating fluidized-bed reactor with a single jet was studied by Hariri et al. Various parameters were involved in agglomeration phenomena -- bed material, fluidization velocity, bed temperature, jet velocity, jet temperature, bed geometry, and distributor geometry. Controlled agglomerates were produced in the fluidized bed when a sloped gas distributor consisting of a central jet and a porous plate was used. Gas at temperatures above the melting temperature of a bed material was introduced into the jet and gas at temperatures below the softening temperature was introduced into the distributor. The rate of agglomerate formation was significantly influenced by an increase in either jet air or auxiliary (grid) air temperature. The extent of agglomeration also depended strongly upon the volume of the hot zone confined within the isotherms with temperatures higher than the melting point of the bed material.

  20. Agglomeration in a fluidized bed using multiple jet streams

    Energy Technology Data Exchange (ETDEWEB)

    Rehmat, A.; Abbasian, J. [Institute of Gas Technology, Chicago, IL (United States); Kothari, M.; Hariri, H.; Arastoopour, H. [Illinois Inst. of Tech., Chicago, IL (United States)

    1992-12-31

    Tests were conducted to determine the overall temperature distribution, temperature in the vicinity of the jets, and the rate of agglomeration in a fluidized bed containing multiple jet streams. Agglomeration of ash during coal gasification increases carbon utilization efficiency considerably. The agglomeration requires a fluidized-bed reactor with a specially designed distributor equipped with a jet to yield a hot zone confined within the bed. The rate of agglomeration depends upon the size and the intensity of the zone. This rate, and hence the unit capacity, could be increased by adding multiple jets to the distributor. The purpose of this study was to verify this phenomenon. The temperature distribution inside the agglomerating fluidized-bed reactor with a single jet was studied by Hariri et al. Various parameters were involved in agglomeration phenomena -- bed material, fluidization velocity, bed temperature, jet velocity, jet temperature, bed geometry, and distributor geometry. Controlled agglomerates were produced in the fluidized bed when a sloped gas distributor consisting of a central jet and a porous plate was used. Gas at temperatures above the melting temperature of a bed material was introduced into the jet and gas at temperatures below the softening temperature was introduced into the distributor. The rate of agglomerate formation was significantly influenced by an increase in either jet air or auxiliary (grid) air temperature. The extent of agglomeration also depended strongly upon the volume of the hot zone confined within the isotherms with temperatures higher than the melting point of the bed material.

  1. The porosity in a fluidized bed heat transfer model

    NARCIS (Netherlands)

    Visser, G.; Valk, M.

    1993-01-01

    A mathematical model of heat transfer between a fluidized bed and an immersed surface and a model of gas flow and porosity, both recently published, were combined and further modified in the area of low velocities where the particle convective component of heat transfer is low or neglectable. Experi

  2. Acoustic monitoring of a fluidized bed coating process

    DEFF Research Database (Denmark)

    Naelapaa, Kaisa; Veski, Peep; Pedersen, Joan G.;

    2007-01-01

      The aim of the study was to investigate the potential of acoustic monitoring of a production scale fluidized bed coating process. The correlation between sensor signals and the estimated amount of film applied and percentage release, respectively, were investigated in coating potassium chloride...

  3. Mechanism of film formation during granules capsulation in fluidized bed

    OpenAIRE

    Ostroha, Ruslan; Yukhymenko, Mykola

    2013-01-01

    It is proposed to perform granules capsulation process in the device of fluidized bed. Analysis of different approaches to mathematical description of granules growth kinetics was made. Equation of size determination of received granules in the device is proposed including granules growth rate and changes of density of granules distribution according to sizes in film forming process.

  4. DESIGN AND APPLICATION OF FLUIDIZED BED PHOTOCATALYTIC REACTOR

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Photocatalytic degradation of organic pollutant is a new and potential method to transform it to harmless inorganic material, such as CO2 and H2O. So far, most of photocatalytic reactors were cylinder or tabulate photoreactor. The relevant photocatalyst was TiO2 nanometer powder. Although a few investigators had aimed their research field to fluidized bed reactor, their reaction systems were of biphase, such as solid-liquid or solid-gas. Few people focused their research on the triphasic fluidized bed photocatalytic reactor[1]. Compared with traditional photoreactors, a triphasic fluidized bed photoreactor has more advantages[2]: (1) The solid photocatalyst can be separated easily. (2) Its configuration meets the requirement of higher surface area-to-volume ratio of photocatalytic, which is much lower in a fixed bed or a plate photoreactor. (3) The UV light can be used more efficiently. (4) The mass transfer conditions can be controlled and improved easily. (5) It suited to pilot-scale or large-scale operations. For the UV light penetration and photon efficiency should be considered, the photocatalytic reactor differed greatly from a typical fluidized bed reactor.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-06-01

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

  6. NOx emission from incineration of organic hazardous liquid waste containing hexamethylendiamine in fluidized bed

    Institute of Scientific and Technical Information of China (English)

    别如山; 李季; 杨励丹

    2002-01-01

    Experiments have been conducted to investigate NOx concentration profiles along bed height and influences of temperature and excess air on NOx emission in the range from 700 ℃ to 900 ℃, when waste water containing 5% Hexamethylenediamine incinerated in a bench scale hot fluidized bed. The testing results indicate that the concentration of NO2 is larger than that of NO along bed height except in the freeboard at 900 ℃, where NO, NO2 concentrations are zero. Temperature and excess air play significant role on NOx emission. With increasing in temperature the NOx emission decreases very rapidly in the range from 700 ℃ to 900 ℃. With increasing in excess air, NOx emission increases considerably at 700 ℃, but it is almost independent of excess air at 800 ℃,and at 900 ℃ NOx emission is zero indicating that NH2 from NH2(CH2)6NH2 has strong effect on de-NOx with increasing in temperature and excess air. NOx concentration profiles decrease progressively with bed height because of reduction of NOx by NH2. The mechanism of NOx formation and destruction is presented in the paper.

  7. Multi—scale Analysis of Chaotic Characteristics in a Gas—Solid Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    ZHENLing; CHENBochuan; 等

    2002-01-01

    Deterministic chaos theory offers useful quantitative tools to characterize the non-linear dynamic behavior of a fluidized bed and the developed complexity theory presents a new approach to evaluate finite sequences. In this paper,the non-linear,hydrodynamic behavior of the pressure flutuation signals in a reactor was discussed by chaos parameters and complexity measures.Coherent results were achieved by our multi-scale analysis,which further exposed the behavior in a gas-solid two-phase system.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

    To extend the operating temperature range and further improve the durability of fluidizable sorbents, zinc titanate, another leading regenerable sorbent, was selected for development in the later part of this project. A number of zinc titanate formulations were prepared in the 50 to 300 [mu]m range using granulation and spray drying methods. Important sorbent preparation variables investigated included zinc to titanium ratio, binder type, binder amount, and various chemical additives such as cobalt and molybdenum. A number of sorbents selected on the basis of screening tests were subjected to bench-scale testing for 10 cycles at high temperature, high pressure (HTHP) conditions using the reactor system designed and constructed during the base program. This reactor system is capable of operation either as a 2.0 in. or 3.0 in. I.D. bubbling bed and is rated up to 20 atm operation at 871[degrees]C. Bench-scale testing variables included sorbent type, temperature (550 to 750[degrees]C), gas type (KRW or Texaco gasifier gas), steam content of coal gas, and fluidizing gas velocity (6 to 15 cm/s). The sorbents prepared by spray drying showed poor performance in terms of attrition resistance and chemical reactivity. On the other hand, the granulation method proved to be very successful. For example, a highly attrition-resistant zinc titanate formulation, ZT-4, prepared by granulation exhibited virtually no zinc loss and demonstrated a constant high reactivity and sulfur capacity over 10 cycles, i.e., approximately a 60 percent capacity utilization, with Texaco gas at 750[degrees]C, 15 cm/s fluidizing velocity and 15 atm pressure. The commercial potential of the granulation method for zinc titanate manufacture was demonstrated by preparing two 80 lb batches of sorbent with zinc to titanium mol ratios of 0.8 and 1.5.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

    To extend the operating temperature range and further improve the durability of fluidizable sorbents, zinc titanate, another leading regenerable sorbent, was selected for development in the later part of this project. A number of zinc titanate formulations were prepared in the 50 to 300 {mu}m range using granulation and spray drying methods. Important sorbent preparation variables investigated included zinc to titanium ratio, binder type, binder amount, and various chemical additives such as cobalt and molybdenum. A number of sorbents selected on the basis of screening tests were subjected to bench-scale testing for 10 cycles at high temperature, high pressure (HTHP) conditions using the reactor system designed and constructed during the base program. This reactor system is capable of operation either as a 2.0 in. or 3.0 in. I.D. bubbling bed and is rated up to 20 atm operation at 871{degrees}C. Bench-scale testing variables included sorbent type, temperature (550 to 750{degrees}C), gas type (KRW or Texaco gasifier gas), steam content of coal gas, and fluidizing gas velocity (6 to 15 cm/s). The sorbents prepared by spray drying showed poor performance in terms of attrition resistance and chemical reactivity. On the other hand, the granulation method proved to be very successful. For example, a highly attrition-resistant zinc titanate formulation, ZT-4, prepared by granulation exhibited virtually no zinc loss and demonstrated a constant high reactivity and sulfur capacity over 10 cycles, i.e., approximately a 60 percent capacity utilization, with Texaco gas at 750{degrees}C, 15 cm/s fluidizing velocity and 15 atm pressure. The commercial potential of the granulation method for zinc titanate manufacture was demonstrated by preparing two 80 lb batches of sorbent with zinc to titanium mol ratios of 0.8 and 1.5.

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

    Science.gov (United States)

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

    2015-02-01

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

  11. Simulation of circulating fluidized bed gasification for characteristic study of pakistani coal

    Directory of Open Access Journals (Sweden)

    Ramzan Naveed

    2015-03-01

    Full Text Available A process model for turbulent pressurized circulating fluidized-bed coal gasifier is created using ASPEN PLUS software. Both hydrodynamic and reaction kinetics parameter are taken into account, whose expressions for fluidized bed are adopted from the literature. Various reactor models available in ASPEN PLUS with calculator as External Block are nested to solve hydrodynamics and kinetics. Multiple operational parameters for a pilot-plant circulating fluidized-bed coal gasifier are used to demonstrate the effects on coal gasification characteristics. This paper presents detailed information regarding the simulation model, including robust analysis of the effect of stoichiometric ratio, steam to coal ratio, gasification temperature and gasification agent temperature. It is observed that, with the increase in the flow rate of air, the components hydrogen, carbon monoxide, carbon dioxide and methane reduce, which causes the Lower Heating Value (LHV of synthesis gas (Syn. Gas to decrease by about 29.3%, while increment in the steam flow rate shows a minute increase in heating value of only 0.8%. Stoichiometric ratio has a direct relationship to carbon conversion efficiency and carbon dioxide production. Increasing the steam to coal ratio boosts the production of hydrogen and carbon monoxide, and causes a drop in both carbon dioxide concentration and the conversion efficiency of carbon. High gasifying agent temperature is desired because of high concentration of CO and H2, increasing carbon conversion and LHV. A high gasifying agent temperature is the major factor that affects the coal gasification to enhance H2 and CO production rapidly along with other gasification characteristics.

  12. First test results of the pilot plant for the pressure loaded vapour loaded fluidized bed drying process (DDWT) of brown coals. A pilot plant for 5 t/h dry coal and till 6 bar dryer pressure; Erste Testergebnisse von der Versuchsanlage zur Druckaufgeladenen Dampfwirbelschicht-Trocknung (DDWT) von Braunkohlen. Versuchsanlage fuer 5 t/h Trockenkohle und bis 6 bar Trocknerdruck

    Energy Technology Data Exchange (ETDEWEB)

    Porsche, T.; Thannhaeuser, L.; Hoehne, O.; Martin, J.S. [Vattenfall Europe Generation AG, Cottbus (Germany)

    2009-07-01

    Apart from other promising possibilities for the improvement of the efficiency of fossil fuelled power stations such as the improvement of the steam parameters and optimization of the equipment technology the preliminary drying of coal possesses a very high potential. This results from a more effective combustion of the dried coal in the power station boiler and from the energetic use of the condensation enthalpy of the coal water vapour during processing the power station. Especially, if the vapour steam is on a high level of pressure, the applied evaporation enthalpy completely can be led back into the power station process. Thereby, improvements of the net efficiency of power stations of about 4 to 5 % are attainable. Starting from October 2008, Vattenfall Europe AG (Berlin, Federal Republic of Germany) established a pilot plant for a vapour loaded fluidized bed drying process (DDWT) of brown coals at the site Schwarze Pumpe. The plant is laid out for a dryer performance of 5 t/h dry brown coal. This plant enables tests with a dryer system pressure between 1 and 6 bar. After start-up in the third quarter 2008, the operation of the pilot plant begun. Extensive tests of the plant and components were accomplished, and the procedure proof for DDWT of Lausitz brown coals was furnished. So far, up to 4 t/h dry coal were produced with the accomplished test campaigns. A dryer system pressure of up to 4.5 bar started. The target is to transfer the results and experiences from the test operation into planning and construction of a 250 MW{sub e}l Oxyfuel demonstration power station with upstream coal pressure drying process which is established by Vattenfall Europe AG at the location Jaenschwalde until 2015.

  13. Particle-scale simulation of fluidized bed with immersed tubes

    Institute of Scientific and Technical Information of China (English)

    Yongzhi ZHAO; Maoqiang JIANG; Yi CHENG

    2008-01-01

    In order to simulate gas-solids flows with complex geometry,the boundary element method was incorporated into the implementation of a combined model of computational fluid dynamics and discrete element method.The resulting method was employed to simulate hydrodynamics in a fluidized bed with immersed tubes.The transient simulation results showed particle and bubble dynamics.The bubble coalescence and break-up behavior when passing the immersed tubes was successfully predicted.The gas-solid flow pattern in the fluidized bed is changed greatly because of the immersed tubes.As particles and gas are come in contact with the immersed tubes,the gas bubbles will be deformed.The collisions between particles arid tubes will make the tubes sur-rounded by air pockets most of the time and this is unfavorable for the heat transfer between particles and tubes.

  14. Circulating fluidized bed coal-saving optimization control method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Tengfei; Li, Dewei; Xi, Yugeng; Zhou, Wu [Shanghai Jiao Tong Univ., Shanghai (China). Dept. of Automation; Ministry of Education, Shanghai (China). Key Lab. of System Control and Information Processing; Yin, Debin [Shanghai Xinhua Control Technology (Group) Co., Ltd., Shanghai (China)

    2013-07-01

    The circulating fluidized bed boiler is widely used in thermal power plants. With the proposal of energy-saving emission reduction, how to reduce coal consumption while ensure the output steam quality at the same time has become an important topic. This paper combines the technology of RTO (real-time optimization) and zone control in DMC (dynamic matrix control) to achieve this goal. The proposed method adds the coal consumption into the objective function of DMC controller and the operation point of the boiler is permitted to change within a zone which can be set according to the actual requirements of the circulating fluidized bed boiler. The zone control in DMC provides the freedom to reduce the coal consumption and achieves the economic optimal target. Compared to the simple use of constrained DMC control, the proposed method is verified to be remarkable coal-saving by the case study of a 150 t/h boiler of a power plant in Sichuan.

  15. Torrefaction of sawdust in a fluidized bed reactor.

    Science.gov (United States)

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

    2012-01-01

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

  16. Carbon Shale Combustion in the Fluidized Bed Reactor

    Directory of Open Access Journals (Sweden)

    Olek Małgorzata

    2014-06-01

    Full Text Available The purpose of this article is to present the possibilities of coal shale combustion in furnaces with bubbling fluidized bed. Coal shale can be autothermally combusted in the fluidized bed, despite the low calorie value and high ash content of fuel. Established concentrations of CO (500 ppm and VOC (30 mg/m3 have indicated a high conversion degree of combustible material during combustion process. Average concentrations of SO2 and NOx in the flue gas were higher than this received from the combustion of high quality hard coal, 600 ppm and 500 ppm, respectively. Optional reduction of SO2 and NOx emission may require the installation of flue gas desulphurization and de-NOx systems.

  17. Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors. 11th technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    Gamwo, I.K.; Miller, A.; Gidaspow, D.

    1992-04-01

    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Spectral analysis of CFB data obtained at Illinois Institute of Technology shows that the frequencies of pressure oscillations are less than 0.1 Hertz and that they increase with solids volume fraction to the usual value of one Hertz obtained in bubbling beds. These data are consistent with the kinetic theory interpretation of density wave propagation.

  18. Experiments and Modelling of Coal Pyrolysis under Fluidized Bed Conditions

    Institute of Scientific and Technical Information of China (English)

    ZhangYongzhe; XuXiangdong; 等

    1999-01-01

    The pyrolysis behavior of two Chinese coals has been investigated in a laboratory-scale bubbling fluidized bed system in Siegen University,Germany,Experimental equipment and procedure are introduced.The amounts of pyrolysis species of each coal were measured,calcuated and compared.A new method was presented to determine the needed parameters in FG-DVC model with the experimental results instead of other much more complicated experiments.

  19. Chemical looping combustion of coal in interconnected fluidized beds

    Institute of Scientific and Technical Information of China (English)

    SHEN LaiHong; ZHENG Min; XIAO Jun; ZHANG Hui; XIAO Rui

    2007-01-01

    Chemical looping combustion is the indirect combustion by use of oxygen carrier.It can be used for CO2 capture in power generating processes. In this paper,chemical looping combustion of coal in interconnected fluidized beds with inherent separation of CO2 is proposed. It consists of a high velocity fluidized bed as an air reactor in which oxygen carrier is oxidized, a cyclone, and a bubbling fluidized bed as a fuel reactor in which oxygen carrier is reduced by direct and indirect reactions with coal. The air reactor is connected to the fuel reactor through the cyclone. To raise the high carbon conversion efficiency and separate oxygen carrier particle from ash, coal slurry instead of coal particle is introduced into the bottom of the bubbling fluidized bed. Coal gasification and the reduction of oxygen carrier with the water gas take place simultaneously in the fuel reactor. The flue gas from the fuel reactor is CO2 and water. Almost pure CO2 could be obtained after the condensation of water. The reduced oxygen carrier is then returned back to the air reactor, where it is oxidized with air. Thermodyanmics analysis indicates that NiO/Ni oxygen carrier is the optimal one for chemical looping combustion of coal.Simulation of the processes for chemical looping combustion of coal, including coal gasification and reduction of oxygen carrier, is carried out with Aspen Plus software. The effects of air reactor temperature, fuel reactor temperature, and ratio of water to coal on the composition of fuel gas, recirculation of oxygen carrier particles, etc., are discussed. Some useful results are achieved. The suitable temperature of air reactor should be between 1050-1150Cand the optimal temperature of the fuel reactor be between 900-950℃.

  20. Chemical looping combustion of coal in interconnected fluidized beds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chemical looping combustion is the indirect combustion by use of oxygen carrier. It can be used for CO2 capture in power generating processes. In this paper, chemical looping combustion of coal in interconnected fluidized beds with inherent separation of CO2 is proposed. It consists of a high velocity fluidized bed as an air reactor in which oxygen carrier is oxidized, a cyclone, and a bubbling fluidized bed as a fuel reactor in which oxygen carrier is reduced by direct and indirect reactions with coal. The air reactor is connected to the fuel reactor through the cyclone. To raise the high carbon conversion efficiency and separate oxygen carrier particle from ash, coal slurry instead of coal particle is introduced into the bottom of the bubbling fluidized bed. Coal gasification and the reduction of oxygen carrier with the water gas take place simultaneously in the fuel reactor. The flue gas from the fuel reactor is CO2 and water. Almost pure CO2 could be obtained after the con- densation of water. The reduced oxygen carrier is then returned back to the air reactor, where it is oxidized with air. Thermodyanmics analysis indicates that NiO/Ni oxygen carrier is the optimal one for chemical looping combustion of coal. Simulation of the processes for chemical looping combustion of coal, including coal gasification and reduction of oxygen carrier, is carried out with Aspen Plus software. The effects of air reactor temperature, fuel reactor temperature, and ratio of water to coal on the composition of fuel gas, recirculation of oxygen carrier par- ticles, etc., are discussed. Some useful results are achieved. The suitable tem- perature of air reactor should be between 1050―1150℃and the optimal temperature of the fuel reactor be between 900―950℃.

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

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

  3. Fluidized bed control system based on inverse system method

    Institute of Scientific and Technical Information of China (English)

    SONG Fu-hua; LI Ping

    2005-01-01

    The invertible of the Large Air Dense Medium Fluidized Bed (ADMFB) were studied by introducing the concept of the inverse system theory of nonlinear systems.Then the ADMFB, which was a multivariable, nonlinear and coupled strongly system,was decoupled into independent SISO pseudo-linear subsystems. Linear controllers were designed for each of subsystems based on linear systems theory. The practice output proves that this method improves the stability of the ADMFB obviously.

  4. Gasification of wood in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, L.C. de; Marti, T.; Frankenhaeuser, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    A first series of gasification experiments with our fluidized bed gasifier was performed using clean sawdust as fuel. The installation and the analytical systems were tested in a parametric study in which gasification temperature and equivalence ratio were varied. The data acquired will serve to establish the differences between the gasification of clean wood and the gasification of Altholz (scrapwood) and wood/plastics mixtures. (author) 1 fig., 3 tabs., 5 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

  6. Anaerobic degradation of linear alkylbenzene sulfonate in fluidized bed reactor

    OpenAIRE

    2010-01-01

    An anaerobic fluidized bed reactor was used to assess the degradation of the surfactant linear alkylbenzene sulfonate (LAS). The reactor was inoculated with sludge from an UASB reactor treating swine wastewater and was fed with a synthetic substrate supplemented with LAS. Sand was used as support material for biomass immobilization. The reactor was kept in a controlled temperature chamber (30±1 ºC) and operated with a hydraulic retention time (HRT) of 18 h. The LAS concentration was gradually...

  7. The heat transfer mechanisms in fluidized beds; Laemmoensiirtomekanismit leijukerroksessa

    Energy Technology Data Exchange (ETDEWEB)

    Fogelholm, C.J.; Blomster, A.M.; Kojola, H. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Energy Technology and Environmental Protection

    1997-10-01

    The goal of the research project is to improve the accuracy of the heat transfer correlation in circulating fluidized beds and to define how the heat transfer is distributed in radiation and convection in the different parts of the fluidized bed. This will be carried out by studying the behaviour and the heat transfer of the fluidized bed in the boundary layer near the wall. During the project the concentration and the velocity of the sand particles are measured. The particle concentration and the particle velocity are measured by an image analysis system. A video camera and a Super VHS recorder are used to capture live images from the bed. The images are digitized and stored on a PC. The measured particle concentration was at highest slightly over 20 % on the straight wall. As expected, the velocity of the fluidizing gas had the most important role on the particle concentration. The experimental studies of the particle velocity were started last autumn 1996. The velocities of the particles were measured by using a multiple exposure technique. Afterwards the images captured were analyzed by performing a Fourier transform analysis. So far the results have been encouraging and the analyzing work will be ended this spring. (orig.)

  8. Erosion of heat exchanger tubes in fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-01-01

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

  9. Operation of a fluidized-bed denitrification bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, P.A.

    1978-11-15

    In the fluidized-bed denitrification process developed, bacteria are allowed to grow and attach themselves to 0.25 to 0.60-mm-OD coal particles, and nitrate-containing solution is pumped up through the column at a velocity sufficient to fluidize the bacteria-coated coal particles. The denitrification bacteria convert the nitrate ions to nitrogen gas. A 10-cm-ID column has been operated by Oak Ridge Y-12 Plant personnel to test the scale-up and operational characteristics of the fluidized bed process. The reactor consists of a tapered bottom section for flow distribution, several straight 10-cm-ID cylindrical sections, and a tapered top section for solid/liquid disengaging. Increasing the diameter of the reactor by a factor of two did not cause any decrease in reactor performance. The fluidized-bed reactor is characterized by short-residence-time requirements (about 2 minutes per meter of height), and by high, but variable, denitrification rates (2 to 35 g NO/sub 3//sup -/-N/dm/sup 3//day). The reactor is best suited for relatively low-concentration nitrate wastes (<1 wt% NO/sub 3//sup -/). The economics of using the reactor for high-concentration wastes (>20 wt% NO/sub 3//sup -/) is less favorable, but still may be competitive with other reactor types. 9 figs, 2 tables.

  10. The heat transfer mechanisms in fluidized beds; Laemmoensiirtomekanismit leijukerroksessa

    Energy Technology Data Exchange (ETDEWEB)

    Fogelholm, C.J.; Blomster, A.M.; Kojola, H. [Helsinki Univ. of Technology, Espoo (Finland)

    1996-12-01

    The goal of the research project is to improve the accuracy of the heat transfer correlation in circulating fluidized beds and to define how the heat transfer is distributed in radiation and convection in the different parts of the fluidized bed. This will be carried out by studying the behaviour and heat transfer of the fluidized bed in the boundary layer near the wall. The total and radiative heat transfer as well as the particle concentration will be measured. Based on the data a correlation will be created. Two different measurement systems are used. The particle concentration is measured by a image-analysis system. A video camera and a Super VHS recorder are used to capture live images from the bed. The images are digitized and stored on a PC. The system has been used in previous research projects at our laboratory. In earlier projects all measurements have been carried out in cold environments. In this project the system will be modified for hot environments. The radiative heat transfer is measured by a radiative heat transfer probe connected to a PC via an A/D converter. The probe consists of a heat flow detector which is isolated from the bed by a sapphire window so that only the radiative part of the heat transfer is detected. The probe will be calibrated in a black body oven so that the effect of the conduction and the sapphire window can be separated. (author)

  11. Novel designs of fluidized bed combustors for low pollutant emissions

    Energy Technology Data Exchange (ETDEWEB)

    Lin, W.; Bleek, C.M. van den [Delft Univ. of Technology (Netherlands). Dept. of Chemical Engineering; Dam-Johansen, K. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering

    1995-12-31

    It is known that NH{sub 3}, released during the devolatilization of fuel, is an important precursor for NO formation in fluidized bed combustors. On the other hand, NH{sub 3} may be used as a reducing agent in the thermal DeNO{sub x} process to reduce NO{sub x} emission levels. In this paper, a new concept of fluidized bed combustors is proposed based on the idea of in situ reduction of NO{sub x} by self-produced NH{sub 3} from fuel without lowering the sulfur capture level. This design is intended to separate the NH{sub 3} release process under reducing conditions from the char combustion process under oxidizing conditions; this self-released NH{sub 3}, together with some combustibles, is mixed with gaseous combustion products in the upper part of the combustor for a further reduction of the NO{sub x} formed during combustion. Furthermore, the combustion of the combustibles may cause the temperature to rise in this upper zone and thereby reduce the emission of N{sub 2}O. The applications of this design to bubbling and circulating fluidized bed combustors are described and the mechanisms of the main reactions involved discussed.

  12. Influence of rolling friction on single spout fluidized bed simulation

    Institute of Scientific and Technical Information of China (English)

    Christoph Goniva; Christoph Kloss; Niels G. Deen; Johannes A. M. Kuipers; Stefan Pirker

    2012-01-01

    In this paper we study the effect of rolling friction on the dynamics in a single spout fluidized bed using Discrete Element Method (DEM) coupled to Computational Fluid Dynamics (CFD).In a first step we neglect rolling friction and show that the results delivered by the open source CFD-DEM framework applied in this study agree with previous simulations documented in literature.In a second step we include a rolling friction sub-model in order to investigate the effect of particle non-sphericity.The influence of particle-particle as well as particle-wall rolling friction on the flow in single spout fluidized bed is studied separately.Adequate rolling friction model parameters are obtained using first principle DEM simulations and data from literature.Finally,we demonstrate the importance of correct modelling of rolling friction for coupled CFD-DEM simulations of spout fluidized beds.We show that simulation results can be improved significantly when applying a rolling friction model,and that experimental data from literature obtained with Positron Emission Particle Tracking (PEPT) technique can be satisfactorily reproduced.

  13. Water softening by induced crystallization in fluidized bed.

    Science.gov (United States)

    Chen, Yuefang; Fan, Rong; An, Danfeng; Cheng, Yujie; Tan, Hazel

    2016-12-01

    Fluidized bed and induced crystallization technology were combined to design a new type of induced crystallization fluidized bed reactor. The added particulate matter served as crystal nucleus to induce crystallization so that the insoluble material, which was in a saturated state, could precipitate on its surface. In this study, by filling the fluidized bed with quartz sand and by adjusting water pH, precipitation of calcium carbonate was induced on the surface of quartz sand, and the removal of water hardness was achieved. With a reactor influent flow of 60L/hr, a fixed-bed height of 0.5m, pH value of 9.5, quartz sand nuclear diameter of 0.2-0.4mm, and a reflux ratio of 60%, the effluent concentration of calcium hardness was reduced to 60mg/L and 86.6% removal efficiency was achieved. The resulting effluent reached the quality standard set for circulating cooling water. Majority of the material on the surface of quartz sand was calculated to be calcium carbonate based on energy spectrum analysis and moisture content was around 15.994%. With the low moisture content, dewatering treatment is no longer required and this results to cost savings on total water treatment process.

  14. COMPUTATIONALLY INTELLIGENT MODELLING AND CONTROL OF FLUIDIZED BED COMBUSTION PROCESS

    Directory of Open Access Journals (Sweden)

    Ivan T Ćirić

    2011-01-01

    Full Text Available In this paper modelling and control approaches for fluidized bed combustion process have been considered, that are based on the use of computational intelligence. Proposed adaptive neuro-fuzzy-genetic modelling and intelligent control strategies provide for efficient combining of available expert knowledge with experimental data. Firstly, based on the qualitative information on the desulphurization process, models of the SO2 emission in fluidized bed combustion have been developed, which provides for economical and efficient reduction of SO2 in FBC by estimation of optimal process parameters and by design of intelligent control systems based on defined emission models. Also, efficient fuzzy nonlinear FBC process modelling strategy by combining several linearized combustion models has been presented. Finally, fuzzy and conventional process control systems for fuel flow and primary air flow regulation based on developed models and optimized by genetic algorithms have also been developed. Obtained results indicate that computationally intelligent approach can be successfully applied for modelling and control of complex fluidized bed combustion process.

  15. Combustion Model FOr Staged Circulating Fluidized Bed BOiler

    Institute of Scientific and Technical Information of China (English)

    FandJianhua; LuQinggang; 等

    1997-01-01

    A mathematical model for atmospheric staged circulating fluidized bed combustion,which takes fluid dynamics,combustion,heat transfer,pollutants formation and retention,into account was developed in the institute of Engineering Thermophysics(IET)recently.The model of gas solid flow at the bottom of the combustor was treated by the two-phase theory of fluidized bed and in the upper region as a core-annulus flow structure.The chemical species CO,CO2,H2,H2O,CH4,O2 and N2 were considered in the reaction process.The mathematical model consisted of sub-modeles of fluid namics,coal heterogeneous and gas homogeneous chemical reactions.heat transfer,particle fragmentation and attrition,mass and energy balance tec.The developed code was applied to simulate an operating staged circulating fluidized bed combustion boiler of early design and the results were in good agreement with the operating data.The main submodels and simulation results are given in this paoper.

  16. Staged fluidized-bed combustion and filter system

    Science.gov (United States)

    Mei, Joseph S.; Halow, John S.

    1994-01-01

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

  17. Numerical Study of Pyrolysis of Biomass in Fluidized Beds

    Science.gov (United States)

    Bellan, Josette; Lathouwers, Danny

    2003-01-01

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

  18. Investigation on Agropellet Combustion in the Fluidized Bed

    Science.gov (United States)

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

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

  19. Application of Scaling-Law and CFD Modeling to Hydrodynamics of Circulating Biomass Fluidized Bed Gasifier

    Directory of Open Access Journals (Sweden)

    Mazda Biglari

    2016-06-01

    Full Text Available Two modeling approaches, the scaling-law and CFD (Computational Fluid Dynamics approaches, are presented in this paper. To save on experimental cost of the pilot plant, the scaling-law approach as a low-computational-cost method was adopted and a small scale column operating under ambient temperature and pressure was built. A series of laboratory tests and computer simulations were carried out to evaluate the hydrodynamic characteristics of a pilot fluidized-bed biomass gasifier. In the small scale column solids were fluidized. The pressure and other hydrodynamic properties were monitored for the validation of the scaling-law application. In addition to the scaling-law modeling method, the CFD approach was presented to simulate the gas-particle system in the small column. 2D CFD models were developed to simulate the hydrodynamic regime. The simulation results were validated with the experimental data from the small column. It was proved that the CFD model was able to accurately predict the hydrodynamics of the small column. The outcomes of this research present both the scaling law with the lower computational cost and the CFD modeling as a more robust method to suit various needs for the design of fluidized-bed gasifiers.

  20. Design and construction of a circulating fluidized bed combustion facility for use in studying the thermal remediation of wastes

    Science.gov (United States)

    Rink, Karl K.; Kozinski, Janusz A.; Lighty, JoAnn S.; Lu, Quing

    1994-08-01

    Fluidized bed combustion systems have been widely applied in the combustion of solid fossil fuels, particularly by the power generation industry. Recently, attention has shifted from the conventional bubbling fluidized bed (BFB) to circulating fluidized bed (CFB) combustion systems. Inherent advantages of CFB combustion such as uniform temperatures, excellent mixing, high combustion efficiencies, and greater fuel flexibility have generated interest in the feasibility of CFB combustion systems applied to the thermal remediation of contaminated soils and sludges. Because it is often difficult to monitor and analyze the combustion phenomena that occurs within a full scale fluidized bed system, the need exists for smaller scale research facilities which permit detailed measurements of temperature, pressure, and chemical specie profiles. This article describes the design, construction, and operation of a pilot-scale fluidized bed facility developed to investigate the thermal remediation characteristics of contaminated soils and sludges. The refractory-lined reactor measures 8 m in height and has an external diameter of 0.6 m. The facility can be operated as a BFB or CFB using a variety of solid fuels including low calorific or high moisture content materials supplemented by natural gas introduced into the fluidized bed through auxiliary fuel injectors. Maximum firing rate of the fluidized bed is approximately 300 kW. Under normal operating conditions, internal wall temperatures are maintained between 1150 and 1350 K over superficial velocities ranging from 0.5 to 4 m/s. Contaminated material can be continuously fed into the fluidized bed or introduced as a single charge at three different locations. The facility is fully instrumented to allow time-resolved measurements of gaseous pollutant species, gas phase temperatures, and internal pressures. The facility has produced reproducible fluidization results which agree well with the work of other researchers. Minimum

  1. Ash and heavy metals in fluidized-bed combustion of wood wastes; Tuhka ja raskasmetallit puuperaeisen jaetteen kerrosleijupoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Kaessi, T.; Aittoniemi, P. [IVO Power Engineering, Vantaa (Finland); Kauppinen, E.; Latva-Somppi, J.; Kurkela, J. [VTT Chemical Technology, Espoo (Finland); Partanen, J. [IVO Technology Centre, Vantaa (Finland)

    1997-10-01

    Ash formation and deposition mechanisms during co-combustion of pulp mill sludge and bark in industrial bubbling fluidized bed (BFB) combustor have been studied. Similar fuels were used in a bench-scale BFB for co-combustion of sludge and bark pellets and comparative studies with separate combustion of these fuels. Results indicated that in industrial scale unit significant fraction of ash had vaporization. About 14 mass-% of the total fly ash was found in the particle size below 0.2 {mu}m. The vaporized species consisted of potassium (K), sulfur (S), chlorine (Cl) and also of minor quantities of sodium (Na). In the benchscale similar vaporization fractions during co-combustion were measured, about 11 mass-%. During the combustion of bark this ratio, about 20 mass-%, was higher than during sludge combustion. The vaporized ash fraction was in the case of dried sludge combustion about 7 mass-%, but with wet sludge the vaporization rate was remarkably lower, about 1-2 mass-%. An increase in the bed temperature increased also ash vaporization. Test run period without combustion at elevated temperatures produced very low quantities of vaporized ash. The vaporized species in bench-scale test during bark pellet combustion were K, S and Cl, for sludge combustion also Na was clearly detected. No condensation of the vaporized species in bed area or furnace walls was observed. Bed defluidization was studied in the bench-scale unit. During bark pellet combustion the bed-agglomeration proceeded via small ash particle, below 2 {mu}m, coating on sand particle surface and consequent bonding between the ash layers. In the case of sludge combustion the accumulation of large ash particles and sintering of these porous agglomerates was observed to cause bed coarsening and defluidization. (orig.)

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

    Science.gov (United States)

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

    1987-09-14

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

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

    Science.gov (United States)

    Scott, Charles D.; Strandberg, Gerald W.

    1989-01-01

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

  4. Agglomeration in fluidized beds at high temperatures: Mechanisms, detection and prevention

    Energy Technology Data Exchange (ETDEWEB)

    Malte Bartels; Weigang Lin; John Nijenhuis; Freek Kapteijn; J. Ruud van Ommen [Delft University of Technology - DelftChemTech, Delft (Netherlands)

    2008-10-15

    Fluidized-bed conversion of solid fuels is a well-established and widely used technology. Yet, operational problems are encountered in industrial practice. One of the most important problems is the occurrence of agglomeration at high temperature, meaning that bed particles adhere to each other to form larger entities (agglomerates). This process is often not recognized until sudden defluidization and often leads to a costly shutdown of the whole installation. In particular, the thermal conversion of certain biomass fuels, which is becoming increasingly popular, increases the risk of agglomeration. This paper critically reviews the current research status of this topic in terms of agglomeration mechanisms, detection and counteraction strategies. To understand the complex phenomenon of agglomeration in fluidized beds at high temperatures different areas are distinguished viz. hydrodynamics, chemical reaction mechanisms, particle interaction mechanisms and molecular cramming. Special emphasis is given to the detection of agglomeration. The range of detection methods is comprised of fuel ash analysis methods to predict potential agglomeration as well as analysis methods based on (on-line) process measurements, such as pressure and temperature. Finally, different methods to counteract agglomeration phenomena are presented; they comprise operational measures, utilization of additives, alternative bed materials and improved reactor design. 176 refs., 22 figs., 1 tab.

  5. An Experimental and Numerical Investigation of Fluidized Bed Gasification of Solid Waste

    Directory of Open Access Journals (Sweden)

    Sharmina Begum

    2013-12-01

    Full Text Available Gasification is a thermo-chemical process to convert carbon-based products such as biomass and coal into a gas mixture known as synthetic gas or syngas. Various types of gasification methods exist, and fluidized bed gasification is one of them which is considered more efficient than others as fuel is fluidized in oxygen, steam or air. This paper presents an experimental and numerical investigation of fluidized bed gasification of solid waste (SW (wood. The experimental measurement of syngas composition was done using a pilot scale gasifier. A numerical model was developed using Advanced System for Process ENgineering (Aspen Plus software. Several Aspen Plus reactor blocks were used along with user defined FORTRAN and Excel code. The model was validated with experimental results. The study found very similar performance between simulation and experimental results, with a maximum variation of 3%. The validated model was used to study the effect of air-fuel and steam-fuel ratio on syngas composition. The model will be useful to predict the various operating parameters of a pilot scale SW gasification plant, such as temperature, pressure, air-fuel ratio and steam-fuel ratio. Therefore, the model can assist researchers, professionals and industries to identify optimized conditions for SW gasification.

  6. Comparative analysis of CFD models for jetting fluidized beds: Effect of particle-phase viscosity

    Institute of Scientific and Technical Information of China (English)

    Pei Pei; Kai Zhang; Gang Xu; Yongping Yang; Dongsheng Wen

    2012-01-01

    Under the Eulerian-Eulerian framework of simulating gas-solid two-phase flow,the accuracy of the hydrodynamic prediction is strongly affected by the selection of rheology of the particulate phase,for which a detailed assessment is still absent.Using a jetting fluidized bed as an example,this work investigates the influence of solid theology on the hydrodynamic behavior by employing different particle-phase viscosity models.Both constant particle-phase viscosity model (CVM) with different viscosity values and a simple two-fluid model without particle-phase viscosity (NVM) are incorporated into the classical twofluid model and compared with the experimental measurements.Qualitative and quantitative results show that the jet penetration depth,jet frequency and averaged bed pressure drop are not a strong function of the particle-phase viscosity.Compared to CVM,the NVM exhibits better predictions on the jet behaviors,which is more suitable for investigating the hydrodynamics of gas-solid fluidized bed with a central jet.

  7. EFFECT OF VERTICAL BAFFLES ON PARTICLE MIXING AND DRYING IN FLUIDIZED BEDS OF GROUP D PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Chung Lim Law; Siti Masrinda Tasirin; Wan Ramli Wan Daud; Derek Geldart

    2003-01-01

    This study reports the effect of vertical baffles on the group D powder mixing and drying characteristics in a batch fluidized bed dryer. Results obtained in this study showed that operating the fluidized bed dryer with vertical baffles gave better particle mixing. This is due to the fact that the vertical baffles acted to limit the growth of small bubbles into large bubbles and the small bubbles caused more vigorous mixing in the bed of particles before finally erupting at the bed surface. Thus, insertion of vertical baffles is a useful way to process group D particles in a fluidized bed, especially when the fluidized bed is large.

  8. Importance of fragmentation on the steady state combustion of wood char in a bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Pinho, Carlos [Universidade do Porto (CEFT/FEUP), Porto (Portugal). Faculdade de Engenharia. Centro de Estudos de Fenomenos de Transporte], E-mail: ctp@fe.up.pt

    2010-07-01

    A simple mathematical model for the analysis of the steady state behavior of a bubbling fluidized bed burner is presented, with the main intention of evaluating the importance of the primary fragmentation of fuel particles on the performance of this type of burners. This model has pedagogical advantages because of its simplicity and easiness of application to the analysis of realistic situations. The model is based upon the classical models used for the study of batch combustion processes in fluidized bed reactors. Experimental data from studies of fluidized bed combustion of portuguese vegetable chars are used to support the analysis of the performance of a 1 m diameter fluidized bed combustor. (author)

  9. Analysis of Pressure Fluctuations in a Dual-leg Fluidized Bed Based on Recurrence Plot%双支腿流化床压力脉动的递归分析

    Institute of Scientific and Technical Information of China (English)

    杨春振; 段钰锋; 胡海韬

    2013-01-01

    Recurrence plot (RP) was used to study the effects of fluidization velocity and bed material inventory on chaotic characteristics in a dual-leg fluidized bed (DL-FB) with dimensions of 0.24 m width, 0.04m depth and 2.0 mm height. The height of dual-leg is 0.16 m. The glass beads with diameters of 0.25-0.28mm were adopted as bed material. The results show that the RP could be utilized effectively to explain the nonlinear dynamic performance in the DL-FB and the chaos of the DL-FB is higher than that of the single distributor FB because of the combination of bubbling actions and solids exchange behavior between two half beds. With the increase of fluidization velocity, entropy as a recurrence quantification parameter varies along with a M-type curve at different fluidization velocities. Four processes were shown for the gas-solids flow in the DL-FB with the increase of the fluidization velocity: lower fluidization velocity with no particles exchange, less solids exchange at lower fluidization velocity, solids exchange and particles dispersion. The trend of the effect of bed inventory on entropy is not obvious.%采用递归图系统研究了流化风速、床存量对双支腿流化床(DL-FB)内气固流动混沌特性的影响规律.DL-FB的宽、深和高分别为0.24、0.04和2.0 m,支腿高为0.16m,使用粒径范围为0.25~0.28的玻璃珠作为床料.结果表明递归图可用于描述DL-FB内的气固两相流动的混沌特性,且DL-FB内的气固流动较单布风板流化床复杂.DL-FB系统熵随着流化气速的增加呈“M”型曲线变化.DL-FB系统随气速的增加会出现低速颗粒未交换段、低速颗粒交换起始段、颗粒交换段和颗粒悬浮段.床存量对系统熵的影响较大且没有明显规律.DL-FB内的压力脉动包含气泡行为和颗粒交换在半床间交换行为.

  10. Employment of fluidized bed ash as a basecourse material; Ryudosho nenshobai wo genryo to shita robanzai no jitsuyoka

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, I. [Center for Coal Utilization, Japan, Tokyo (Japan); Tsuzura, K. [Naruto Salt Mfg. Co. Ltd., Tokushima (Japan); Izumi, H. [Nippon Hodo Co. Ltd., Tokyo (Japan); Goto, H. [Electric Power Development Co. Ltd., Tokyo (Japan); Nagaoka, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1996-09-01

    Generation of coal ash from coal burning fluidized beds reaches 400,000 tons annually, which is anticipated to increase still more in the future. This paper relates to works to develop a basecourse material manufacturing technology by utilizing excellent hydration and solidification characteristics of fluidized bed ash. The developmental works have been moved forward as a subsidy operation of the Agency of Natural Resources and Energy. Upon having obtained a prospect of practical application of the development, the research results are reported in this paper. Coal ash produced in a fluidized bed boiler goes through the following processes: it is added with water and kneaded; formed into rectangular parallelepiped having sides of 10 to 30 cm long by using a forming machine of vibrating and pressurizing type; cured in steam at 60 degC; crushed into sizes smaller than 40 mm; and made into a basecourse material upon adjusting the grain size. A pilot plant completed in 1993 has produced 15,000 tons of the material to date. Properties required as a basecourse material, such as hazardous metal dissolving characteristics and strength sufficiently meet relevant standards or the targeted value. Demonstration tests of the material on roads including public roads have shown as good result as those obtained from standard basecourse materials. 8 refs., 8 figs., 7 tabs.

  11. Investigation of the baffle effects on reactor of fluidized beds with circulating flow along with ozone decomposition

    Directory of Open Access Journals (Sweden)

    E. Zohrabi

    2016-09-01

    Full Text Available Fluidized beds with circulating flow, as the gas-solid contactors, are widely used in physical and chemical processes such as drying of solids, pharmaceutical industries, coating solids, granulation, and water and wastewater treatment industry. In this study, numerical simulation using FLUENT software was conducted to investigate the distribution of solid particles of fluidized beds with circulating flow. To conduct simulation, Eulerian-Eulerian with the help of kinetic theory of granular flow was used. Various values of particle-wall elastic modulus were studied. After selecting the appropriate model to predict the particles flow behavior, ozone decomposition reaction was carried out in fluidized beds with circulating flow and they were solved by FLUENT software. The results showed that the location of ring baffles has the greatest impact on fluctuation of system pressure drop, and adverse mix of gas and increase of solid materials are tangible by baffles, resulting from regulation of bed and accumulation of circulating particles beside the wall.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-03-31

    assessment and a market plan for large-scale fabrication of sorbents were developed. As an optional task, long-term bench-scale tests of the best moving-bed sorbents were conducted. Starting from thermodynamic calculations, several metal oxides were identified for potential use as hot gas cleanup sorbents using constructed phase stability diagrams and laboratory screening of various mixed-metal oxide formulations. Modified zinc titanates and other proprietary metal oxide formulations were evaluated at the bench scale and many of them found to be acceptable for operation in the target desulfurization temperature range of 370 C (700 F) to 538 C (1000 F) and regeneration temperatures up to 760 C (1400 F). Further work is still needed to reduce the batch-to-batch repeatability in the fabrication of modified zinc titanates for larger scale applications. The information presented in this Volume 1 report contains the results of moving-bed sorbent development at General Electric's Corporate Research and Development (GE-CRD). A separate Volume 2 report contains the results of the subcontract on fluidized-bed sorbent development at the Institute of Gas Technology (IGT).

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

    Energy Technology Data Exchange (ETDEWEB)

    Wei-Ping Pan; Yan Cao; John Smith

    2008-05-31

    On February 14, 2002, President Bush announced the Clear Skies Initiative, a legislative proposal to control the emissions of nitrogen oxides (NO{sub x}), sulfur dioxide (SO{sub 2}), and mercury from power plants. In response to this initiative, the National Energy Technology Laboratory organized a Combustion Technology University Alliance and hosted a Solid Fuel Combustion Technology Alliance Workshop. The workshop identified multi-pollutant control; improved sorbents and catalysts; mercury monitoring and capture; and improved understanding of the underlying reaction chemistry occurring during combustion as the most pressing research needs related to controlling environmental emissions from fossil-fueled power plants. The Environmental Control Technology Laboratory will help meet these challenges and offer solutions for problems associated with emissions from fossil-fueled power plants. The goal of this project was to develop the capability and technology database needed to support municipal, regional, and national electric power generating facilities to improve the efficiency of operation and solve operational and environmental problems. In order to effectively provide the scientific data and the methodologies required to address these issues, the project included the following aspects: (1) Establishing an Environmental Control Technology Laboratory using a laboratory-scale, simulated fluidized-bed combustion (FBC) system; (2) Designing, constructing, and operating a bench-scale (0.6 MW{sub th}), circulating fluidized-bed combustion (CFBC) system as the main component of the Environmental Control Technology Laboratory; (3) Developing a combustion technology for co-firing municipal solid waste (MSW), agricultural waste, and refuse-derived fuel (RDF) with high sulfur coals; (4) Developing a control strategy for gaseous emissions, including NO{sub x}, SO{sub 2}, organic compounds, and heavy metals; and (5) Developing new mercury capturing sorbents and new

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

    Energy Technology Data Exchange (ETDEWEB)

    AYALA, R E; VENKATARAMANI, V S

    1998-09-30

    cost assessment and a market plan for large-scale fabrication of sorbents were developed. As an optional task, long-term bench-scale tests of the best moving-bed sorbents were conducted. Starting from thermodynamic calculations, several metal oxides were identified for potential use as hot gas cleanup sorbents using constructed phase stability diagrams and laboratory screening of various mixed-metal oxide formulations. Modified zinc titanates and other proprietary metal oxide formulations were evaluated at the bench scale and many of them found to be acceptable for operation in the target desulfurization temperature range of 370 °C (700 °F) to 538 °C (1000 °F) and regeneration tempera-tures up to 760 °C (1400 °F). Further work is still needed to reduce the batch-to-batch repeatability in the fabrication of modified zinc titanates for larger scale applications. The information presented in this Volume 1 report contains the results of moving-bed sorbent develop-ment at General Electric's Corporate Research and Development (GE-CRD). A separate Volume 2 report contains the results of the subcontract on fluidized-bed sorbent development at the Institute of Gas Technology (IGT).

  15. Cold test with a benchtop set-up for fluidized bed reactor using quartz sand to simulate gasification of coal cokes by concentrated solar radiation

    Science.gov (United States)

    Gokon, Nobuyuki; Tanabe, Tomoaki; Shimizu, Tadaaki; Kodama, Tatsuya

    2016-05-01

    The impacts of internal circulation of a mixture of coal-coke particles and quartz sand on the fluidization state in a fluidized bed reactor are investigated by a cold test with a benchtop set-up in order to design 10-30 kWth scale prototype windowed fluidized-bed reactor. Firstly, a basic relationship between pressure loss of inlet gas and gas velocity was experimentally examined using quartz sand with different particle sizes by a small-scale quartz tube with a distributor at ambient pressure and temperature. Based on the results, an appropriate particle range of quartz sand and layer height/layer diameter ratio (L/D ratio) was determined for a design of the fluidized bed reactor. Secondly, a windowed reactor mock-up was designed and fabricated for solar coke gasification using quartz sand as a bed material. The pressure loss between the inlet and outlet gases was examined, and descending cokes and sand particles on the sidewall of the reactor was observed in the reactor mock-up. The moving velocity and distance of descending particles/sands from the top to bottom of fluidized bed were measured by the visual observation of the colored tracer particles on outside wall of the reactor.

  16. Characterization of a fluidized-bed combustion ash to determine potential for environmental impact. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hassett, D.J.; Henderson, A.K.; Pflughoeft-Hassett, D.F.; Mann, M.D.; Eylands, K.E.

    1997-10-01

    A 440-megawatt, circulating fluidized-bed combustion (CFBC), lignite-fired power plant is planned for construction in Choctaw County north of Ackerman, Mississippi. This power plant will utilize Mississippi lignite from the first lignite mine in that state. Malcolm Pirnie, Inc., is working with the power plant developer in the current planning and permitting efforts for this proposed construction project. In order to accommodate Mississippi state regulatory agencies and meet appropriate permit requirements, Malcolm Pirnie needed to provide an indication of the characteristics of the by-products anticipated to be produced at the proposed plant. Since the Mississippi lignite is from a newly tapped mine and the CFBC technology is relatively new, Malcolm Pirnie contacted with the Energy and Environmental Research Center (EERC) to develop and perform a test plan for the production and characterization of ash similar to ash that will be eventually produced at the proposed power plant. The work performed at the EERC included two primary phases: production of by-products in a bench-scale CFBC unit using lignite provided by Malcolm Pirnie with test conditions delineated by Malcolm Pirnie to represent expected operating conditions for the full-scale plant; and an extensive characterization of the by-products produced, focusing on Mississippi regulatory requirements for leachability, with the understanding that return of the by-product to the mine site was an anticipated by-product management plan. The overall focus of this project was the environmental assessment of the by-product expected to be produced at the proposed power plant. Emphasis was placed on the leachability of potentially problematic trace elements in the by-products. The leaching research documented in this report was performed to determine trends of leachability of trace elements under leaching conditions appropriate for evaluating land disposal in monofills, such as returning the by-products to the mine

  17. Hydrodynamics of Biomass Gasification in a Dual Chamber Circulating Fluidized Bed Reactor

    Directory of Open Access Journals (Sweden)

    Wahyu Haifa

    2016-01-01

    Full Text Available This paper presents work on hydrodynamics of several types of biomass mixture in a dual chamber circulating fluidized bed. In designing the CFBreactornecessary to know the distribution of solid particles radially and axially influenced by fluidizing gas velocity, particle size, solid circulation flux, reactor diameter and height of the reactor. These factors will affect pressure drop along the riser of the reaction chamber. Pressure drop is an important factor in the study of hydrodynamics of particle flow. The pressure drop was measured using mathematical model compared to experimental results done on a cold mode. Since it was found that both results were consistent which means that the model can be used to predict the operating parameters of CFB design.

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

    Energy Technology Data Exchange (ETDEWEB)

    Krutka, Holly; Wilson, Cody; Starns, Travis

    2016-05-31

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

  19. Gasification of sawdust in pressurised internally circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Maartensson, R.; Lindblom, M. [Lund Univ. (Sweden). Dept. of Chemical Engineering

    1996-12-31

    A test plant for pressurised gasification of biofuels in a internally circulating fluidized bed has been built at the department of Chemical Engineering II at the University of Lund. The design performance is set to maximum 20 bar and 1 050 deg C at a thermal input of 100 kW or a maximum fuel input of 18 kg/in. The primary task is to study pressurised gasification of biofuels in relation to process requirements of the IGCC concept (integrated gasification combined cycle processes), which includes studies in different areas of hot gas clean-up in reducing atmosphere for gas turbine applications. (orig.)

  20. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

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

    1980-01-01

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

  1. Temperature distribution and control in liquefied petroleum gas fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Li Wang; Ping Wu; Yanping Zhang; Jing Yang; Lige Tong

    2004-01-01

    Temperature distribution and control have been investigated in a liquefied petroleum gas (LPG) fluidized bed with hollow corundum spheres (A12O3) of 0.867-1.212 mm in diameter at moderately high temperatures (800-1100℃). Experiments were carried out for the air consumption coefficient α in the range of 0.3 to 1.0 and the fluidization number N in the range of 1.3 to 3.0. Particle properties, initial bed height, α and N all affect temperature distribution in the bed. Bed temperature can be adjusted about 200℃ by combined the adjusting of α and N.

  2. Dynamical simulation of fluidized beds - hydrodynamically interacting granular particles

    CERN Document Server

    Ichiki, K; Ichiki, Kengo; Hayakawa, Hisao

    1995-01-01

    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.

  3. HYDRODYNAMIC CHARACTERISTICS OF FLUIDIZED BEDS CONTAINING LARGE POLYDISPERSED PARTICLES

    Directory of Open Access Journals (Sweden)

    K. TANNOUS

    1998-03-01

    Full Text Available This paper presents a hydrodynamic study of fluidized beds containing large polydispersed particles (B and D categories of Geldart’s classification. The experiments have been carried out with particle samples characterized by the Rosin-Rammler-Sperling (RRS size distribution. The parameters analyzed in this study are the dispersion index and the average particle diameter obtained from the RRS size distribution model. Correlations to estimate the initial and complete fluidization velocities and the segregation velocity as a function of these two size distribution parameters have been established.

  4. Modeling of Sulfur Retention in Circulating Fluidized Bed Coal Combustors

    Institute of Scientific and Technical Information of China (English)

    乔锐; 吕俊复; 刘青; 吴学安; 岳光溪

    2001-01-01

    A comprehensive model for predicting the sulfur retention performance in circulating fluidized bedcombustors was developed which involves the different residence times, the wide particle size distribution andthe different forms of sulfur in the coal. In addition, the reductive decomposition of CaSO4 is highlighted. Thesimulation results from the model show that the sulfur contents, the bed temperature, the sorbent particle sizedistribution and the sorbent activity or the maximum conversion rate can significantly influence the sulfuretention performance in circulating fluidized bed (CFB) combustors.``

  5. Agricultural uses of alkaline fluidized bed combustion ash: case studies

    Energy Technology Data Exchange (ETDEWEB)

    Stout, W.L.; Daily, M.R.; Nickeson, T.L.; Svendson, R.L.; Thompson, G.P. [USDA-ARS, University Park, PA (United States)

    1997-06-01

    Successful programmes were developed by Ahlstrom Development Ash Corporation and Air Products and Chemical for using fluidized bed combustion ash as a substitute for agricultural lime on dairy farms in northern New York state and on fruit and nut crops in the San Joaquin Valley of California. The companies developed these programmes by utilizing the methodology developed through USDA-ARS research and working closely with agricultural consultants and regulatory agencies to ensure that the ash applications were both agronomically and environmentally sound. 1 ref.

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

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

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

  7. Effects of sintered metal distributor on fluidization quality of the air dense medium fluidized bed

    Institute of Scientific and Technical Information of China (English)

    Yang Xuliang; Zhao Yuemin; Luo Zhenfu; Chen Zengqiang; Song Shulei

    2011-01-01

    Dry coal beneficiation using an air dense medium fluidized bed (ADMFB) requires the formation of a stable and uniform bed from the dense medium.Others have shown that the structure and geometric parameters of the air distributor have a significant influence on the experimentally observed fluidization quality.In this study we used a sintered metal distributor (SMD) in the ADMFB separator and study its effect on the fluidization quality.The results show that for the same open area ratio (OAR),a smaller aperture in the SMD will provide improved fluidization quality.If aperture size is held constant bigger open area ratios result in improved fluidization quality.And,the fluidization quality also improves when the pressure drop across the SMD increases.A model relating distributor pressure drop and the geometric parameters of the SMD is also proposed.

  8. The preparation of calcium superoxide in a flowing gas stream and fluidized bed

    Science.gov (United States)

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

    1980-01-01

    Superoxides can be used as sources of chemically stored oxygen in emergency breathing apparatus. The work reported here describes the use of a low-pressure nitrogen gas sweep through the reactant bed, for temperature control and water vapor removal. For a given set of gas temperature, bed thickness, and reaction time values, the highest purity calcium superoxide, Ca(O2)2, was obtained at the highest space velocity of the nitrogen gas sweep. The purity of the product was further increased by flow conditions that resulted in the fluidization of the reactant bed. However, scale-up of the low-pressure fluidized bed process was limited to the formation of agglomerates of reactant particles, which hindered thermal control by the flowing gas stream. A radiofrequency flow discharge inside the reaction chamber prevented agglomeration, presumably by dissipation of the static charges on the fluidized particles.

  9. Discrete element study of granulation in a spout-fluidized bed

    NARCIS (Netherlands)

    Link, J.M.; Godlieb, W.; Deen, N.G.; Kuipers, J.A.M.

    2007-01-01

    In this work a discrete element model (DEM) is presented for the description of the gas–liquid–solid flow in a spout-fluidized bed including all relevant phenomena for the study of granulation. The model is demonstrated for the case of a granulation process in a flat spout-fluidized bed, containing

  10. Combustion and co-combustion of biomass in a bubbling fluidized bed boiler

    NARCIS (Netherlands)

    Khan, A.A.

    2007-01-01

    This PhD dissertation concerns the study of different aspects of biomass (co)-combustion in small-scale fluidized bed boilers for heat generation. The most renowned gaseous emissions from fluidized bed combustion, namely, CO and NO, are investigated with the help of experimental and theoretical stud

  11. Fluidized beds as turbulence promoters in the concentration of food liquids by reverse osmosis

    NARCIS (Netherlands)

    Boer, de R.; Zomerman, J.J.; Hiddink, J.; Aufderheyde, J.; Swaay, van W.P.M.; Smolders, C.A.

    1980-01-01

    Fluidized beds offer a potential improvement of reverse osmosis processes for food liquids, less fouling of the membrane, and reduced energy consumption. Our experiments were concerned with tubular systems in which fluidized beds of glass, steel, and lead beads were used. Glass beads appeared to be

  12. DETERMINATION OF MARGINALLY STABLE ZONE OF GAS-SOLID MAGNETICALLY FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The void fluctuation of magnotically fluidized beds was analyzed and their maginally stable zone was determined. The analysis was based on the two-phase model of magnetically fluidized bed and wave theory. The marginally stable zone determined by this paper matches well with the experimental results.

  13. Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-29

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

  14. Cold-Flow Circulating Fluidized-Bed Identification

    Energy Technology Data Exchange (ETDEWEB)

    Parviz Famouri

    2005-07-01

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

  15. Suspended solid abatement in a conical fluidized bed flocculator

    Institute of Scientific and Technical Information of China (English)

    Dandan ZHOU; Shuangshi DONG; Keyu LI; Huizhong JIANG; Dandan SHANG

    2013-01-01

    With the random movement of silica gel beads in a conical fluidized bed, micro-vortices resulting from the fluidization promoted the collision and aggregation of suspended fine kaolin powders. The abatement efficiencies of the suspended fine solids under several hydrodynamic conditions were studied, and a suitable control strategy for operating the conical fluidized bed flocculators was identified. The suspended solids abatement efficiency was found to increase with increasing Camp Number and flocculation time (T), but decreased with the increase of velocity gradient (G) within the range studied in this research (165.1-189.6s-1). The abatement efficiencies were all more than 60% at the range of G = 165-180 s 1 and T = 15-33 s at an initial kaolin solid concentration of 150mg·L-1, polymer aluminum chloride dosage of 60 mg· L -1 and sedimentation time of 20 min. However, the formation of flocs was influenced by the liquid back- mixing. Excessive backmixing caused the breakup of ftocs and resulted in difficulty for the fine powders to aggregate and sediment to the reactor bottom. The results of the calculated fractal dimension and measured free sedimenta- tion velocity of flocs obtained at different runs showed similar flocs properties, and indicated an easy control strategy for sedimentation of the flocs.

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

    Science.gov (United States)

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

    1991-08-20

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

  17. Vibrated fluidized bed air classification of moist raw coal

    Institute of Scientific and Technical Information of China (English)

    杨国华; 赵跃民; 陈清如

    2002-01-01

    Vibrated fluidized bed air classification is completely different from traditional screening in principle. It extracts fine coal from moist raw coal by entrainment of an ascending airflow in a vibrated fluidized bed. Pilot tests showed that air classification efficiencies varied from 74.85% to 93.84% at cut-size 6, 4, 3, 2, 1, and 0.5 mm when free moisture of coal is in the range of 1.7% to 9.5%, and ash contents of fine coal products were 2%~3% lower than those of the same size fractions in feed, and 4%~10% lower than those of feeds for most cases because of the density differences between coal and waste, which is beneficial to producing lower ash fine coal from raw coal as fuel of blast furnaces or pulverized coal firing boilers. A commercial unit of 100 t/h has been in smooth operation, and several 300~400 t/h units are in plan or construction.

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

    Science.gov (United States)

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

    2014-12-01

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

  19. Effect of hot vapor filtration on the characterization of bio-oil from rice husks with fast pyrolysis in a fluidized-bed reactor.

    Science.gov (United States)

    Chen, Tianju; Wu, Ceng; Liu, Ronghou; Fei, Wenting; Liu, Shiyu

    2011-05-01

    To produce high quality bio-oil from biomass using fast pyrolysis, rice husks were pyrolyzed in a 1-5 kg/h bench-scale fluidized-bed reactor. The effect of hot vapor filtration (HVF) was investigated to filter the solid particles and bio-char. The results showed that the total bio-oil yield decreased from 41.7% to 39.5% by weight and the bio-oil had a higher water content, higher pH, and lower alkali metal content when using HVF. One hundred and twelve different chemical compounds were detected by gas chromatography-mass spectrometry (GC-MS). The molecular weight of the chemical compounds from the condenser and the EP when the cyclone was coupled with HVF in the separation system decreased compared with those from the condenser and EP when only cyclone was used.

  20. FLASH PYROLYSIS OF BIOMASS PARTICLES IN FLUIDIZED BED FOR BIO-OIL PRODUCTION

    Institute of Scientific and Technical Information of China (English)

    Shurong Wang; Mengxiang Fang; Chunjiang Yu; Zhongyang Luo; Kefa Cen

    2005-01-01

    Biomass utilization could relieve the pressure caused by conventional energy shortage and environmental pollution. Advantage should be taken of the abundant biomass in China as clean energy source to substitute for traditional fossil fuels. At present, flash pyrolysis appears to be an efficient method to produce high yields of liquids that could either be directly used as fuel or converted to other valuable chemicals. Experiments were carried out of pyrolyzing biomass particles in a hot dense fluidized bed of sand to obtain high-quality bio-oil. Among four kinds of biomass species adopted in our experiment, Padauk Wood had the best characteristics in producing bio-oil. GC-MS analysis showed bio-oil to be a complex mixture consisting of many compounds. Furthermore, an integrated model was proposed to reveal how temperature influences biomass pyrolysis. Computation indicated that biomass particles underwent rapid heating before pyrolysis.

  1. An Experimental Investigation on Solid Acceleration Length in the Riser of a Long Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Systematic experimental work was conducted to investigate the solid acceleration length in a 16m long circulating fluidized bed riser with fluid cracking catalyst particles over a wide range of operating conditions. A more feasible method is proposed to determine the acceleration length from the measured axial profiles of pressure gradient (or apparent solid holdup). With this new method and large amount of experimental data, a clear picture on the variation of the acceleration length with both solid circulating rate and superficial gas velocity is obtained.It is found that the acceleration length increases generally with increasing solid flow rate and/or decreasing gas velocity. However, the trend in variation of the acceleration length with operating conditions are quite different in different operation ranges. Reasonable explanations are suggested for the observed variation patterns of acceleration length.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-24

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

  3. Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).

    Energy Technology Data Exchange (ETDEWEB)

    Oelfke, John Barry; Torczynski, John Robert; O' Hern, Timothy John; Tortora, Paul Richard; Bhusarapu, Satish (; ); Trujillo, Steven Mathew

    2006-08-01

    An experimental program was conducted to study the multiphase gas-solid flow in a pilot-scale circulating fluidized bed (CFB). This report describes the CFB experimental facility assembled for this program, the diagnostics developed and/or applied to make measurements in the riser section of the CFB, and the data acquired for several different flow conditions. Primary data acquired included pressures around the flow loop and solids loadings at selected locations in the riser. Tomographic techniques using gamma radiation and electrical capacitance were used to determine radial profiles of solids volume fraction in the riser, and axial profiles of the integrated solids volume fraction were produced. Computer Aided Radioactive Particle Tracking was used to measure solids velocities, fluxes, and residence time distributions. In addition, a series of computational fluid dynamics simulations was performed using the commercial code Arenaflow{trademark}.

  4. Ash agglomeration during fluidized bed gasification of high sulphur content lignites

    Energy Technology Data Exchange (ETDEWEB)

    Marinov, V.; Marinov, S.P.; Lazarov, L.; Stefanova, M. (SRTI Energydesign, Sofia (Bulgaria))

    1992-09-01

    Intensive ash agglomeration has hampered the fluidized bed gasification of lignites from the Elhovo deposit (Bulgaria) containing 5.9 wt% sulphur in the dry state. Samples of slag and agglomerates from the pilot plant have been examined by means of chemical, X-ray analysis, IR spectroscopy and scanning electron microscopy. Pyrrhotite (FeS) and wustite (FeO) have been established in the agglomerates, where junctions between ash particles have been found to consist of magnetite, spinel and garnet grains. The chemical reactions leading to garnet formation have been studied. Centres of sintering and centres of melting during the ash agglomeration process have been distinguished. The pyrite product, an eutectic of FeS and FeO melting at 924[degree]C, is assumed to be responsible for the cessation of lignite gasification with steam and air under pressure at a bed temperature of 930[degree]. 11 refs., 3 figs., 6 tabs.

  5. Growth kinetics of calcium fluoride at high supersaturation in a fluidized bed reactor.

    Science.gov (United States)

    Jiang, K; Zhou, K G; Yang, Y C; Du, H

    2014-01-01

    Crystallization process in a fluidized bed reactor (FBR) has been regarded as an environmentally friendly technology for the removal and recovery of fluoride from industrial wastewater. The growth kinetics of calcium fluoride at high supersaturation was studied for design, control, and operation of an FBR. The main variables, including supersaturation, superficial velocity, pH value, and particle size of seed that influenced the crystal growth were investigated. Then, a growth model was used to predict the linear growth rate of calcium fluoride at a high influent concentration of fluoride. The pressure difference in the FBR was used as a feature to characterize the growth rate of calcium fluoride. The aggregation and adsorption between seeds and fine particles were proven to be a possible mechanism for growth of calcium fluoride.

  6. Co-gasification of Colombian coal and biomass in fluidized bed: An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Jhon F. Velez; Farid Chejne; Carlos F. Valdes; Eder J. Emery; Carlos A. Londono [Universidad Nacional de Colombia, Antioquia (Colombia). Grupo de Termodinamica Aplicada y Energias Alternativas

    2009-03-15

    The main results of an experimental work on co-gasification of Colombian biomass/coal blends in a fluidized bed working at atmospheric pressure are reported in this paper. Several samples of blends were prepared by mixing 6-15wt% biomass (sawdust, rice or coffee husk) with coal. Experimental assays were carried out by using mixtures of different steams/blends (Rvc) and air/blend (Rac) ratios showing the feasibility to implement co-gasification as energetic alternative to produce fuel gas to heat and to generate electricity and the possibility of converting clean and efficiently the refuse coal to a low-heating value gas. 29 refs., 5 figs., 4 tabs.

  7. Bench-Scale Development of a Hot Carbonate Absorption Process with Crystallization-Enabled High Pressure Stripping for Post-Combustion CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yongqi

    2014-02-01

    This report summarizes the methodology and preliminary results of a techno-economic analysis on a hot carbonate absorption process (Hot-CAP) with crystallization-enabled high pressure stripping for post-combustion CO{sub 2} capture (PCC). This analysis was based on the Hot-CAP that is fully integrated with a sub-critical steam cycle, pulverized coal-fired power plant adopted in Case 10 of the DOE/NETL’s Cost and Performance Baseline for Fossil Energy Plants. The techno-economic analysis addressed several important aspects of the Hot-CAP for PCC application, including process design and simulation, equipment sizing, technical risk and mitigation strategy, performance evaluation, and cost analysis. Results show that the net power produced in the subcritical power plant equipped with Hot-CAP is 611 MWe, greater than that with Econoamine (550 MWe). The total capital cost for the Hot-CAP, including CO{sub 2} compression, is $399 million, less than that for the Econoamine PCC ($493 million). O&M costs for the power plant with Hot-CAP is $175 million annually, less than that with Econoamine ($178 million). The 20-year levelized cost of electricity (LCOE) for the power plant with Hot-CAP, including CO2 transportation and storage, is 119.4 mills/kWh, a 59% increase over that for the plant without CO2 capture. The LCOE increase caused by CO{sub 2} capture for the Hot-CAP is 31% lower than that for its Econoamine counterpart.

  8. Influence of Chemical and Thermodynamic Parameters on the Flue Gas Desulphurization Efficiency in a Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    Baoguo FAN; Changfu YOU; Haiying QI; Guangming XIANG; Xuchang XU

    2001-01-01

    An experimental study has been performed systematically on flue gas desulphurization by using circulating fluidized bed. The relationship, between desulphurization efficiency and the parameters of thermodynamics and chemistry, was investigated basically. It is shown that the bed temperature and the vapor partial pressure in the bed are the important parameters that influence the desulphurization efficiency. The closer the bed temperature to the dew point and the higher the vapor partial pressure, the higher is the desulphurization efficiency. With increasing of Ca/S, the desulphurization efficiency ascends. Comparing with different operating methods, the optimum method has been found.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-15

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

  10. Air gasification of empty fruit bunch for hydrogen-rich gas production in a fluidized-bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, M.A.A.; Salmiaton, A.; Wan Azlina, W.A.K.G.; Mohammad Amran, M.S.; Fakhru' l-Razi, A. [Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2011-02-15

    A study on gasification of empty fruit bunch (EFB), a waste of the palm oil industry, was investigated. The composition and particle size distribution of feedstock were determined and the thermal degradation behaviour was analysed by a thermogravimetric analysis (TGA). Then fluidized bed bench scale gasification unit was used to investigate the effect of the operating parameters on EFB air gasification namely reactor temperature in the range of 700-1000 C, feedstock particle size in the range of 0.3-1.0 mm and equivalence ratio (ER) in the range of 0.15-0.35. The main gas species generated, as identified by a gas chromatography (GC), were H{sub 2}, CO, CO{sub 2} and CH{sub 4}. With temperature increasing from 700 C to 1000 C, the total gas yield was enhanced greatly and reached the maximum value ({proportional_to}92 wt.%, on the raw biomass sample basis) at 1000 C with big portions of H{sub 2} (38.02 vol.%) and CO (36.36 vol.%). Feedstock particle size showed an influence on the upgrading of H{sub 2}, CO and CH{sub 4} yields. The feedstock particle size of 0.3-0.5 mm, was found to obtain a higher H{sub 2} yield (33.93 vol.%), and higher LHV of gas product (15.26 MJ/m{sup 3}). Equivalence ratio (ER) showed a significant influence on the upgrading of hydrogen production and product distribution. The optimum ER (0.25) was found to attain a higher H{sub 2} yield (27.31 vol.%) at 850 C. Due to the low efficiency of bench scale gasification unit the system needs to be scaling-up. The cost analysis for scale-up EFB gasification unit showed that the hydrogen supply cost is RM 6.70/kg EFB (2.11/kg = 0.18/Nm{sup 3}). (author)

  11. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-07-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidizing gas,(3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  12. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-10-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidising gas, (3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger, and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  13. An aerated and fluidized bed membrane bioreactor for effective wastewater treatment with low membrane fouling

    KAUST Repository

    Ye, Yaoli

    2016-09-24

    Anaerobic fluidized bed membrane bioreactors (AFMBRs) use granular activated carbon (GAC) particles suspended by recirculation to effectively treat low strength wastewaters (∼100–200 mg L−1, chemical oxygen demand, COD), but the effluent can contain dissolved methane. An aerobic fluidized bed membrane bioreactor (AOFMBR) was developed to avoid methane production and the need for wastewater recirculation by using rising air bubbles to suspend GAC particles. The performance of the AOFMBR was compared to an AFMBR and a conventional aerobic membrane bioreactor (AeMBR) for domestic wastewater treatment over 130 d at ambient temperatures (fixed hydraulic retention time of 1.3 h). The effluent of the AOFMBR had a COD of 20 ± 8 mg L−1, and a turbidity of <0.2 NTU, for low-COD influent (153 ± 19 and 214 ± 27 mg L−1), similar to the AeMBR and AFMBR. For the high-COD influent (299 ± 24 mg L−1), higher effluent CODs were obtained for the AeMBR (38 ± 9 mg L−1) and AFMBR (51 ± 11 mg L−1) than the AOFMBR (26 ± 6 mg L−1). Transmembrane pressure of the AOFMBR increased at 0.04 kPa d−1, which was 20% less than the AeMBR and 57% less than the AFMBR, at the low influent COD. Scanning electron microscopy (SEM) analysis indicated a more uniform biofilm on the membrane in AOFMBR than that from the AeMBR biofilm, and no evidence of membrane damage. High similarity was found between communities in the suspended sludge in the AOFMBR and AeMBR (square-root transformed Bray–Curtis similarity, SRBCS, 0.69). Communities on the GAC and suspended sludge were dissimilar in the AOFMBR (SRBCS, 0.52), but clustered in the AFMBR (SRBCS, 0.63).

  14. Sulfur removal in advanced two-stage fluidized-bed combustion. [Quarterly] technical report, December 1, 1993--February 28, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Hill, A.H.; Wangerow, J.R.; Rue, D.M. [Inst. of Gas Technology, Chicago, IL (United States)

    1994-06-01

    The objective of this study is to obtain data on the rates of reaction between, hydrogen sulfide (H{sub 2}S) and uncalcined calcium-based sorbents under operating conditions relevant to first stage (carbonizer) of Advanced Two-Stage Pressurized Fluidized-Bed Combustors (PFBC). In these systems the CO{sub 2} partial pressure in the first stage generally exceeds the equilibrium value for calcium carbonate decomposition. Therefore, removal of sulfur compounds takes place through the reaction between H{sub 2}S and calcium carbonate. To achieve this objective the rates of reaction between hydrogen sulfide and uncalcined calcium-based sorbents will be determined by conducting tests in pressurized thermogravimetric analyzer (TGA) and high-pressure/high-temperature fluidized-bed reactor (HPTR) units. The effects of sorbent type, sorbent particle size, reactor temperature and pressure, and CO{sub 2} and H{sub 2}S partial pressures on the sulfidation reaction rate will be determined. During this quarter, the high-pressure thermogravimetric analyzer (HPTGA) unit was installed and the shakedown process was completed. Several tests were conducted in the HPTGA unit to establish the operating procedure and the repeatability of the experimental results. Sulfidation by conducting the baseline sulfidation tests. The results are currently being analyzed.

  15. Continuous fluidized-bed contactor with recycle of sorbent

    Science.gov (United States)

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

    1996-01-01

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

  16. Nitrogen Chemistry in Fluidized Bed Combustion of Coal

    DEFF Research Database (Denmark)

    Jensen, Anker Degn

    The present Ph.D thesis describes an experimental and theoretical investigation of the formation and destruction of nitrogen oxides (NOx and N2O) in fluidized bed combustion (FBC) of coal. A review of the current knowledge of nitrogen chemistry in FBC is presented. The review covers both laboratory...... for the emission of NOx from FBC has been developed as part of a JOULE project. The model is based on the two-phase theory of fluidization for the bed with a Kunii-Levenspiel type freeboard model and includes submodels for coal devolatilization, combustion of volatiles and char and a detailed model of NO formation...... plant were used for model verification. The simulations of the NO emission during staged combustion and NH3 injection for NO reduction were in qualitative agreement with the experimental data. A parametric study of the influence of operating conditions on the conversion of fuel-N to NO showed...

  17. Bubbling fluidized bed boiler for Vanaja power plant

    Energy Technology Data Exchange (ETDEWEB)

    Sormunen, R.; Haermae, P.; Vessonen, K.; Ketomaeki, A. [ed.

    1998-07-01

    At the Vanaja Power Plant, on the outskirts of Haemeenlinna, there have been changes which reflect the central goals in IVO`s product development work. At Vanaja, efficiency is combined with environmental friendliness. In the early 1980s, the plant was modernized to produce district heat in addition to electricity. At that time, along with the new gas turbine at the plant, the main fuel, coal, while remaining the fuel for the old boilers, was replaced by natural gas. This year a new type of bubbling fluidized bed boiler enabling continuous use of peat and trial use of biofuels along with coal was introduced at the plant. In addition to the Nordic countries, this kind of technology is required in central eastern Europe, where modernization of ageing power plants is being planned to achieve the best possible solutions in respect of production and the environment. IVO develops a new repair technique for underwater sites

  18. Evaluation of Fluidized Bed Reactor in treating Dyeing effluent

    Directory of Open Access Journals (Sweden)

    S. Poongoth

    2012-07-01

    Full Text Available Textile dyeing industries one of the complicated industries which use many chemicals like dyes, starch, acids, alkalis, surfactants and refractory organics for their process. As it is a wet process it requires more amount of water ranging 65-104 L/Kg of product and it discharges 52-95 L/Kg of product as wastewater. The COD, BOD,TDS, Colour and SS are the major pollutants from these industries to the receiving streams. Biological treatment is employed mostly when compared to the physicochemical treatment. More sludge, toxic bye products and cost for the treatment are the reasons for not employing the physiochemical treatment processes. Biological treatments like aerobic and anaerobic processes overcome the disadvantages of physicochemical treatment. The present study evaluates the Aerobic Fluidized bed Reactor for the treatment of Dyeing effluent. It has been observed through this study that 89% colour removal and 83.3% COD removal were achieved.

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

    Science.gov (United States)

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

    2016-03-01

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

  20. Internal circulating fluidized bed incineration system and design algorithm.

    Science.gov (United States)

    Tian, W D; Wei, X L; Li, J; Sheng, H Z

    2001-04-01

    The internal circulating fluidized bed (ICFB) system is characterized with fast combustion, low emission, uniformity of bed temperature and controllability of combustion process. It is a kind of novel clean combustion system, especially for the low-grade fuels, such as municipal solid waste (MSW). The experimental systems of ICFB with and without combustion were designed and set up in this paper. A series of experiments were carried out for further understanding combustion process and characteristics of several design parameters for MSW. Based on the results, a design routine for the ICFB system was suggested for the calculation of energy balance, airflow rate, heat transfer rate, and geometry arrangement. A test system with ICFB combustor has been set up and the test results show that the design of the ICFB system is successful.

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

    Directory of Open Access Journals (Sweden)

    Kosowska-Golachowska Monika

    2016-03-01

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

  2. Detachment of multi species biofilm in circulating fluidized bed bioreactor.

    Science.gov (United States)

    Patel, Ajay; Nakhla, George; Zhu, Jingxu

    2005-11-20

    In this study, the detachment rates of various microbial species from the aerobic and anoxic biofilms in a circulating fluidized bed bioreactor (CFBB) with two entirely separate aerobic and anoxic beds were investigated. Overall detachment rate coefficients for biomass, determined on the basis of volatile suspended solids (VSS), glucose and protein as well as for specific microbial groups, i.e., for nitrifiers, denitrifiers, and phosphorous accumulating organisms (PAOs), were established. Biomass detachment rates were found to increase with biomass attachment on carrier media in both beds. The detachment rate coefficients based on VSS were significantly affected by shear stress, whereas for protein, glucose and specific microbial groups, no significant effect of shear stress was observed. High detachment rates were observed for the more porous biofilm structure. The presence of nitrifiers in the anoxic biofilm and denitrifiers in the aerobic biofilm was established by the specific activity measurements. Detachment rates of PAOs in aerobic and anoxic biofilms were evaluated.

  3. Internal circulating fluidized bed system and design algorithm

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The internal circulating fluidized bed (ICFB) system ischaracterized with fast combustion, low emission, uniformity of bed temperature and controllability of combustion process. It is a kind of novel clean combustion system, especially for the low-grade fuels, such as municipal solid waste(MSW). The experimental systems of ICFB with and without combustion were designed and set up in this paper. A series of experiments were carried out for further understanding combustion process and characteristics of several design parameters for MSW. Based on the results, a design routine for the ICFB system was suggested for the calculation of energy balance, airflow rate, heat transfer rate, and geometry arrangement. A test system with ICFB combustor has been set up and the test results show that the design of the ICFB system issuccessful.

  4. Mass transfer in three-phase fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Wu, B.W.; Cheng, Y.L.; Perini, J.R.; Roux-Buisson, J.L.

    1978-04-26

    The effects of superficial liquid and gas velocity, particle diameter, liquid viscosity, and column diameter on liquid dispersion (E/sub L) and mass transfer (K/sub L/a) in three-phase fluidized beds were investigated using a water--glycerol/oxygen--nitrogen (or oxygen--argon)/glass-bead system. Overall mass transfer coefficients were calculated based on plug flow, dispersed plug flow, and continuously stirred tank models. k/sub L/a was found to increase with gas velocity and particle diameter, but no correlation of K/sub L/a with liquid velocity was observed. At low liquid velocities, K/sub L/a was lower for the more viscous liquid; the reverse was true at high liquid flow rates. E/sub L/ increased rapidly for liquid flow rates at two to three times the minimum fluidization velocity.

  5. Computational Fluid Dynamics Simulation of Fluidized Bed Polymerization Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Rong [Iowa State Univ., Ames, IA (United States)

    2006-01-01

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

  6. Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor

    Directory of Open Access Journals (Sweden)

    Dmitry Yu. Murzin

    2008-09-01

    Full Text Available In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood, was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5°C/min was applied to the heating until a reactor temperature of 460 °C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-oils. Levoglucosan was the dominant product in the cellulose pyrolysis oil. Acetic acid was found in the highest concentrations in both the galactoglucomannan and in the pine wood pyrolysis oils. Acetic acid is most likely formed by removal of O-acetyl groups from mannose units present in GGM structure.

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

    Science.gov (United States)

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

    2016-09-01

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

  8. Anaerobic degradation of linear alkylbenzene sulfonate in fluidized bed reactor

    Directory of Open Access Journals (Sweden)

    L. L. Oliveira

    2010-12-01

    Full Text Available An anaerobic fluidized bed reactor was used to assess the degradation of the surfactant linear alkylbenzene sulfonate (LAS. The reactor was inoculated with sludge from an UASB reactor treating swine wastewater and was fed with a synthetic substrate supplemented with LAS. Sand was used as support material for biomass immobilization. The reactor was kept in a controlled temperature chamber (30±1 ºC and operated with a hydraulic retention time (HRT of 18 h. The LAS concentration was gradually increased from 8.2±1.3 to 45.8±5.4 mg.L-1. The COD removal was 91%, on average, when the influent COD was 645±49 mg.L-1. The results obtained by chromatographic analysis showed that the reactor removed 93% of the LAS after 270 days of operation.

  9. Devolatilization of wood and wastes in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Barea, Alberto; Nilsson, Susanna; Vidal Barrero, Fernando; Campoy, Manuel

    2010-11-15

    Experiments were carried out in a laboratory fluidized bed (FB) to characterize the devolatilization behavior of wood and various wastes at temperatures applicable to FB gasification and combustion, i.e. 750-900 C. The fuels tested were pellets made of wood, meat and bone meal, and compost (from municipal solid wastes), as well as dried granulates of sewage sludge (DSS). Determination of yields of char, condensate and light gas, as well as the composition of the gas and the time of devolatilization during the pyrolysis of single fuel batches was made. A simple model was developed to analyze the mode of conversion of a single wood pellet and DSS granulate, giving insight on the controlling mechanisms during devolatilization. The devolatilization kinetics of DSS was determined by tests using fine granulates. The model was successfully applied to simulate the conversion of large DSS granulates and wood pellets under the whole range of temperatures analyzed. (author)

  10. Thermofluid effect on energy storage in fluidized bed reactor

    Science.gov (United States)

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

    2016-05-01

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

  11. Fluidized bed spray granulation: analysis of heat and mass transfers and dynamic particle populations

    Directory of Open Access Journals (Sweden)

    S. Heinrich

    2005-06-01

    Full Text Available A model was developed taking into consideration the heat and mass transfer processes in liquid-sprayed fluidized beds. Such fluidized beds (FB are used for granulation, coating and agglomeration. Conclusions are drawn on the relevance of particle dispersion, spraying and drying to temperature and concentrations distributions. In extension, the model was coupled with a population balance model to describe the particle size distribution and the seeds formation for continuous external FBSG (fluidized bed spray granulation with non-classifying product discharge and a screening and milling unit in the seeds recycle. The effects of seeds formation on the stability of the process is discussed.

  12. Motion analysis of waste rock in gas-solids fluidized bed in coal dry beneficiation

    Institute of Scientific and Technical Information of China (English)

    郭迎福; 陈安华; 张永忠; 邓志鹏; 毛树楷

    2002-01-01

    Through the analysis of forces acting on the waste rock in the gas-solid fluidized bed, the waste rock velocity equations and displacement equations in the gas-solids fluidized bed were achieved and the influential factors of the waste rock motion in the fluidized bed were studied in this paper. The conclusions show that the primary factors influencing the waste rock motion are the waste rock grain size and the scraper velocity according to the computer simulation. This has provided the theoretical foundation both for improving the separating effect and ascertaining the length of the separating cell.

  13. Artificial neural network models for biomass gasification in fluidized bed gasifiers

    DEFF Research Database (Denmark)

    Puig Arnavat, Maria; Hernández, J. Alfredo; Bruno, Joan Carles

    2013-01-01

    bed gasifier can be successfully predicted by applying neural networks. ANNs models use in the input layer the biomass composition and few operating parameters, two neurons in the hidden layer and the backpropagation algorithm. The results obtained by these ANNs show high agreement with published......Artificial neural networks (ANNs) have been applied for modeling biomass gasification process in fluidized bed reactors. Two architectures of ANNs models are presented; one for circulating fluidized bed gasifiers (CFB) and the other for bubbling fluidized bed gasifiers (BFB). Both models determine...

  14. Bioreactors with Light-Beads Fluidized Bed: The Voidage Function and its Expression

    Directory of Open Access Journals (Sweden)

    Iliev Vasil

    2014-12-01

    Full Text Available Light-beads fluidized bed bioreactors with gel particles are an attractive alternative for the implementation of a system with immobilized cells. They have a number of advantages: soft operating conditions, ability to work in an ideal mixing regime, intensification of heat- and mass transfer processes in the fermentation system. The expansion characteristics of the fluidized bed were investigated in the present work. The fluidized bed expansion was described using the voidage function. It was found that the voidage can be described by nonlinear regression relationships and the regression coefficients were a function of the particles parameters.

  15. Volatiles combustion in fluidized beds. [Quarterly] technical progress report, 4 December 1994--4 March 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pendergrass II, R.A.; Mansker, L.D.; Hesketh, R.P.

    1995-08-01

    The goal of this project is to investigate the conditions in which volatiles will bum within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization are being conducted to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. The work conducted during the period 4 December, 1994 through, 3 March 1995 is presented in this technical progress report. The research consists of the application of a detailed chemical kinetics model for propane combustion and planned improvements in the experimental system.

  16. BENCH-SCALE STEAM REFORMING OF ACTUAL TANK 48H WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Burket, P; Gene Daniel, G; Charles Nash, C; Carol Jantzen, C; Michael Williams, M

    2008-09-25

    Fluidized Bed Steam Reforming (FBSR) has been demonstrated to be a viable technology to remove >99% of the organics from Tank 48H simulant, to remove >99% of the nitrate/nitrite from Tank 48H simulant, and to form a solid product that is primarily carbonate based. The technology was demonstrated in October of 2006 in the Engineering Scale Test Demonstration Fluidized Bed Steam Reformer1 (ESTD FBSR) at the Hazen Research Inc. (HRI) facility in Golden, CO. The purpose of the Bench-scale Steam Reformer (BSR) testing was to demonstrate that the same reactions occur and the same product is formed when steam reforming actual radioactive Tank 48H waste. The approach used in the current study was to test the BSR with the same Tank 48H simulant and same Erwin coal as was used at the ESTD FBSR under the same operating conditions. This comparison would allow verification that the same chemical reactions occur in both the BSR and ESTD FBSR. Then, actual radioactive Tank 48H material would be steam reformed in the BSR to verify that the actual tank 48H sample reacts the same way chemically as the simulant Tank 48H material. The conclusions from the BSR study and comparison to the ESTD FBSR are the following: (1) A Bench-scale Steam Reforming (BSR) unit was successfully designed and built that: (a) Emulated the chemistry of the ESTD FBSR Denitration Mineralization Reformer (DMR) and Carbon Reduction Reformer (CRR) known collectively as the dual reformer flowsheet. (b) Measured and controlled the off-gas stream. (c) Processed real (radioactive) Tank 48H waste. (d) Met the standards and specifications for radiological testing in the Savannah River National Laboratory (SRNL) Shielded Cells Facility (SCF). (2) Three runs with radioactive Tank 48H material were performed. (3) The Tetraphenylborate (TPB) was destroyed to > 99% for all radioactive Bench-scale tests. (4) The feed nitrate/nitrite was destroyed to >99% for all radioactive BSR tests the same as the ESTD FBSR. (5) The

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

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, R.A.

    1990-08-01

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

  18. Fluidized-bed reactor model with generalized particle balances. Part 1. Formulation and solution

    Energy Technology Data Exchange (ETDEWEB)

    Overturf, B.W.; Reklaitis, G.V.

    1983-09-01

    In this first part, a particle balance model is developed for a fluidized-bed gas-solid reactor which accommodates particle distributions dependent on both size and density, as well as populations consisting of multiple solids.

  19. Design and simulation of a circulating fluidized bed to clean the products of biomass gasification

    Energy Technology Data Exchange (ETDEWEB)

    Uchoa Neto, Moises; Carvalho, Yuri de Araujo [Dept. de Engenharia Mecanica. Faculdade de Tecnologia. Universidade de Brasilia, DF (Brazil); Oliveira, Taygoara Felamingo de; Barcelos, Manuel [Faculdade do Gama. Universidade de Brasilia, Gama, DF (Brazil)], e-mail: taygoara@unb.br

    2010-07-01

    The main goal of this work is to design a workbench circulating fluidized bed to study the cracking of tar in gases from the processes of biomass gasification. For this, a design methodology based on analytical results and empirical correlations for fluidized beds was employed. In parallel, a numerical code of open source technology (MFIX) for the solution of the transport equations of the multiphase flow in the column of a fluidized bed was used to give support to the choice of the design elements. The whole project of the workbench fluidized bed was completely developed, whose operation parameters such as bed geometry, gas velocity, circulating ratio and void fraction characterize a fast fluidization process. A preliminary mesh convergence study was executed with the numerical tool, that was validated comparing with analytical results. Among the most important results, the code computed the predicted value for the minimum fluidization. (author)

  20. Combustion of low grade fractions of Lubnica coal in fluidized bed

    Directory of Open Access Journals (Sweden)

    Mladenović Milica R.

    2012-01-01

    Full Text Available In this paper a method of examination of fuel suitability for fluidized bed combustion is presented. The research of combustion characteristics of low grade fractions of Lubnica brown coal in the fluidized bed by the aforementioned methodology has been carried out on a laboratory semi-industrial apparatus of 200 kWt. Description of the experimental fluidized bed combustion facility is given, as well as experimental results, with the focus on furnace temperature distribution, in order to determine the location of the zone of intensive combustion. Based on investigation results, which are focused on combustion quality (combustion completion as well as on satisfying the environmental protection criteria, it can be stated that the investigated coal is suitable for burning in bubbling, as well as in circulating fluidized bed.

  1. Use of a gas-solid fluidized bed bioreactor for bioaugmentation

    Energy Technology Data Exchange (ETDEWEB)

    Behns, W.; Friedrich, K.; Haida, H. [Magdeburg Univ. (Germany). Inst. fuer Apparate- und Umwelttechnik

    1998-04-01

    Experimental research has shown that microbiological degradation in soils really contaminated with mineral oil hydrocarbons and hexachlorocyclohexane respectively can be accelerated and even intensified by a combined treatment in a fluidized bed bioreactor and subsequently in a remediation heap. (orig.)

  2. Mechanistic modelling of fluidized bed drying processes of wet porous granules

    DEFF Research Database (Denmark)

    Mortier, Séverine Thérèse F.C.; De Beer, Thomas; Gernaey, Krist;

    2011-01-01

    Fluidized bed dryers are frequently used in industrial applications and also in the pharmaceutical industry. The general incentives to develop mechanistic models for pharmaceutical processes are listed, and our vision on how this can particularly be done for fluidized bed drying processes of wet...... will reside in a certain interval. Population Balance Model (ling) (PBM) offers a tool to describe the distribution of particle properties which can be of interest for the application. PBM formulation and solution methods are therefore reviewed. In a fluidized bed, the granules show a fluidization pattern...... Eddy Simulation (LES). Another important aspect of CFD is the choice between the Eulerian–Lagrangian and the Eulerian–Eulerian approach. Finally, the PBM and CFD frameworks can be integrated, to describe the evolution of the moisture content of granules during fluidized bed drying....

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

    OpenAIRE

    Nurdil Eskin; Afsin Gungor

    2005-01-01

    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 different height and volume ratios of the immersed surfaces, both for circu...

  4. An Experimental and Numerical Investigation of Fluidized Bed Gasification of Solid Waste

    OpenAIRE

    Sharmina Begum; Mohammad G. Rasul; Delwar Akbar; David Cork

    2013-01-01

    Gasification is a thermo-chemical process to convert carbon-based products such as biomass and coal into a gas mixture known as synthetic gas or syngas. Various types of gasification methods exist, and fluidized bed gasification is one of them which is considered more efficient than others as fuel is fluidized in oxygen, steam or air. This paper presents an experimental and numerical investigation of fluidized bed gasification of solid waste (SW) (wood). The experimental measurement of syngas...

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

    OpenAIRE

    Sun, Jingyuan; Yan, Yong

    2016-01-01

    Gas-solid fluidization is a well-established technique to suspend or transport particles and has been applied in a variety of industrial processes. Nevertheless, our knowledge of fluidization hydrodynamics is still limited for the design, scale-up and operation optimization of fluidized bed reactors. It is therefore essential to characterize the two-phase flow behaviours in gas-solid fluidized beds and monitor the fluidization processes for control and optimization. A range of non-intrusive t...

  6. Explosion protection in fluidized beds; Explosionsschutz an Wirbelschichtanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Siwek, R. [FireEx Consultant GmbH, Giebenach (Switzerland)

    2002-09-01

    Measures for preventive and constructive explosion protection of fluidized bed systems were first published in 'Sicherheitsregeln fuer den Explosionsschutz bei der Konstruktion und Errichtung von Wirbelschicht-sprueh-granulatoren, Wirbelschichttrocknern, Wirbelschicht-Coatinganlagen' by Hauptverband der gewerblichen Berufsgenossenschaften. The authors stressed the importance of constant updating. In 1997, the VDI Kommission Reinhaltung der Luft started to work on the update of VDI 2263 No.5. This guideline 'Staubbraende und Staubexplosionen Gefahren - Beurteilung - Schutzmassnahmen, Explosionsschutz bei Wirbelschichtanlagen' was published as a draft version in March 2002. A supplement, No. 5.1, was published as a draft version in October 2002; it presents examples of risk assessments and protective measures and requires knowledge of VDI 2263 No. 5. This contribution summarizes specifications of hazards in fluidized beds when working withe burnable dust/air mixtures, vapour/air mixtures, or hybrid mixtures. Further, improvements of constructive explosion protection measures are pointed out, and the limits of application of the two VDI regulations are compared. [German] In den 'Sicherheitsregeln fuer den Explosionsschutz bei der Konstruktion und Errichtung von Wirbelschicht - Sprueh - Granulatoren, Wirbelschichttrocknern, Wirbelschicht - Coatinganlagen' des Hauptverbandes der gewerblichen Berufsgenossenschaften [1] wurden erstmalig Massnahmen des vorbeugenden und konstruktiven Explosionsschutzes an Wirbelschichtanlagen entsprechend dem damaligen Wissenstand zusammenfassend dargestellt. Die Verfasser wiesen aber bereits damals darauf hin, dass die Wirkung solcher Sicherheitsregeln auf Dauer nur dann gewaehrleistet sind, wenn sie durch weitere Erkenntnisse aus der fortschreitenden Entwicklung immer wieder ergaenzt werden. Im Jahre 1997 wurde durch die VDI-Kommission Reinhaltung der Luft die erste Sitzung zur Novellierung der Richtlinie VDI

  7. Combustion en lit fluidisé Fluidized-Bed Combustion

    Directory of Open Access Journals (Sweden)

    Chrysostome G.

    2006-11-01

    Full Text Available Après quelques rappels généraux sur la fluidisation où seront présentés en par-ticulier les avantages qu'elle offre en combustion, on exposera l'état actuel du développement des générateurs à lit fluidisé opérant avec les combustibles suivants : charbon, combustibles pétroliers, résidus divers ; il sera fait mention de la contribution de l'Institut Français du Pétrole (IFP dans les deux derniers domaines.On présentera ensuite les installations les plus récentes en traitement de minerais (grillage des sulfures, calcination de calcaires. En raison de son importance on examinera encore les possibilités de désulfuration au sein de lits fluidisés, de même que seront commentés les travaux de régénération des absorbants.On terminera enfin en mentionnant les développements des lits circulants ou rapides, considérés comme les réacteurs de la seconde génération. After a general review of fluidization including in particular the advantages it offers for combustion, this article describes the present state of the development of fluidized-bed gcnerators operating with the following fuels : cool, petroleum fuels, different residues. Mention is made of Institut Français du Pétrole (IFP contribution in the last two fields. Then the most recent ore-treating installations are described (roasting of sulfides, calcination of limestones. Because of its importance, the possibilities of desulfurizoticn inside fluidized beds is examined, and research on the regeneration of absorbants is commented on. The article ends by mentioning the development of circulating or fast beds which are considered as second generation reactors.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, B.N.; Shchipko, M.L.; Golovin, Yu. [Inst. of Chemistry of Natural Organic Materials, Academgorodok, Krasnoyarsk (Russian Federation)

    1995-12-01

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

  9. Experimental studies on pulp and paper mill sludge ash behavior in fluidized bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Latva-Somppi, J. [VTT Chemical Technology, Espoo (Finland). Process Technology

    1998-11-01

    Ash formation during the fluidized bed combustion (FBC) of pulp and paper mill sludges has been experimentally studied on an industrial and bench scale. The methods included aerosol measurements, chemical and crystalline composition analyses, thermogravimetry and electron microscopy. Fly ash mass and number size distributions and elemental enrichment in submicron particles and bottom ash were measured. Fly ash, bottom ash and ash deposits were characterized and their formation mechanisms are discussed. During combustion the fine paper-making additives in sludge, clay minerals and calcite, sintered fanning porous agglomerates. The fly ash mass mean size was 7.5 - 15 lam and the supermicron particles included 93.6 - 97.3 % of the fly ash. Condensation of the volatilized inorganic species formed spherical submicron particles in the fly ash. Their mass concentration was almost negligible when co-firing paper mill sludges and wood. This suggests that the fraction of the volatilized inorganic species in the paper mill sludges was low. Results from pulp mill sludge and bark co-firing were different. A clear mass mode below 0.3 pm, presenting 2.2 - 5.0 weight-% of the fly ash was detected. The condensed species included K, Na, S and Cl. Their mass fraction was higher in the pulp mill sludge than in the paper mill sludge. Evidently this resulted in increased volatilization and formation of condensed particles. The following trace elements were enriched in the submicron ash during pulp mill sludge and wood co-firing: As, Cd, Rb and Pb. The main part of the volatile species was, however, captured in the bulk ash. Presumably, this was due to the high surface area concentration in the bulk ash. Sludge moisture was observed to reduce the inorganic species volatilization. Probably steam vaporization from the wet sludge through the burning layer decreased combustion temperatures on char surface and less char was produced. Hence, the volatilization of ash forming species was

  10. Operation of a fluidized-bed bioreactor for denitrification

    Energy Technology Data Exchange (ETDEWEB)

    Hancher, C W; Taylor, P A; Napier, J M

    1978-01-01

    Two denitrification fluidized-bed bioreactors of the same length (i.e., 5 m) but with different inside diameters (i.e., 5 and 10 cm) have been operated on feed ranging in nitrate concentration from 200 to 2000 g/m/sup 3/; thus far, good agreement has been obtained. Two 10-cm-ID bioreactors operating in series have also been tested; the results are in accordance with predicted results based on the performance of a 5-cm-ID bioreactor. The overall denitrification rate in the dual 10-cm-ID bioreactor system was found to be 23 kg N(NO/sub 3//sup -/)/day-m/sup 3/ using feed with a nitrate concentration of 1800 g/m/sup 3/. Data obtained in operating-temperature tests indicate that the maximum denitrification rate is achieved between 22 and 30/sup 0/C. These data will form the basis of the design of our mobile pilot plant which consists of dual 20-cm-ID by 7.3-m-long bioreactors.

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

    Energy Technology Data Exchange (ETDEWEB)

    Williams, M

    2008-05-09

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

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

    Science.gov (United States)

    Poryles, Raphaël; Vidal, Valérie; Varas, Germán

    2016-03-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Varsha Midha; M K Jha; Apurba Dey

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-09-30

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

    Owens, N. J. P.

    1986-01-01

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

  19. Circulating fluidized bed biological reactor for nutrients removal

    Institute of Scientific and Technical Information of China (English)

    Yubo CUI; Hongbo LIU; Chunxue BAI

    2008-01-01

    A new biological nitrogen removal process, which is named herein "The circulating fluidized bed bio-reactor (CFBBR)", was developed for simultaneous removal of nitrogen and organic matter. This process was composed of an anaerobic bed (Riser), aerobic bed (Downer) and connecting device. Influent and nitrified liquid from the aerobic bed enters the anaerobic bed from the bottom of the anaerobic bed, completing the removal of nitrogen and organic matter. The system performance under the conditions of different inflow loadings and nitrified liquid recirculation rates ranging from 200% to 600% was examined. From a technical and economic point of view, the optimum nitrified liquid recirculation rate was 400%. With a shortest total retention time of 2.5 h (0.8 h in the anaerobic bed and 1.5 h in the aerobic bed) and a nitrified liquid recir-culation rate of 400% based on the intluent flow rate, the average removal efficiencies of total nitrogen (TN) and sol-uble chemical oxygen demand (SCOD) were found to be 88% and 95%, respectively. The average effluent concentra-tions of TN and SCOD were 3.5 mg/L and 16 mg/L, respectively. The volatile suspended solid (VSS) concentra-tion, nitrification rate and denitrification rate in the system were less than 1.0 g/L, 0.026-0.1 g NH4+-N/g VSS.d, and 0.016-0.074 g NOx--N/g VSS.d, respectively.

  20. Sorption-enhanced steam methane reforming in fluidized bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Kim

    2006-10-15

    Hydrogen is considered to be an important potential energy carrier; however, its advantages are unlikely to be realized unless efficient means can be found to produce it without generation of CO{sub 2}. Sorption-enhanced steam methane reforming (SE-SMR) represent a novel, energy-efficient hydrogen production route with in situ CO{sub 2} capture, shifting the reforming and water gas shift reactions beyond their conventional thermodynamic limits. The use of fluidized bed reactors for SE-SMR has been investigated. Arctic dolomite, a calcium-based natural sorbent, was chosen as the primary CO{sub 2}-acceptor in this study due to high absorption capacity, relatively high reaction rate and low cost. An experimental investigation was conducted in a bubbling fluidized bed reactor of diameter 0.1 m, which was operated cyclically and batch wise, alternating between reforming/carbonation conditions and higher-temperature calcination conditions. Hydrogen concentrations of >98 mole% on a dry basis were reached at 600 C and 1 atm, for superficial gas velocities in the range of {approx}0.03-0.1 m/s. Multiple reforming-regeneration cycles showed that the hydrogen concentration remained at {approx}98 mole% after four cycles. The total production time was reduced with an increasing number of cycles due to loss of CO{sub 2}-uptake capacity of the dolomite, but the reaction rates of steam reforming and carbonation seemed to be unaffected for the conditions investigated. A modified shrinking core model was applied for deriving carbonation kinetics of Arctic dolomite, using experimental data from a novel thermo gravimetric reactor. An apparent activation energy of 32.6 kj/mole was found from parameter fitting, which is in good agreement with previous reported results. The derived rate expression was able to predict experimental conversion up to {approx}30% very well, whereas the prediction of higher conversion levels was poorer. However, the residence time of sorbent in a continuous

  1. Attempts on cardoon gasification in two different circulating fluidized beds

    Directory of Open Access Journals (Sweden)

    Chr. Christodoulou

    2014-11-01

    Full Text Available Few tests have been carried out in order to evaluate the use of cardoon in gasification and combustion applications most of the researchers dealt with agglomeration problems. The aim of this work is to deal with the agglomeration problem and to present a solution for the utilization of this biofuel at a near industrial application scale. For this reason, two experiments were conducted, one in TU Delft and one in Centre for Research and Technology Hellas (CERTH, using fuel cardoon and 50% w/w cardoon blended with 50% w/w giant reed respectively. Both experimental campaigns were carried out in similar atmospheric circulating fluidized bed gasifiers. Apart from the feedstock, the other differences were the gasification medium and the bed material used in each trial. The oxidizing agent at TUD׳s run was O2/steam, whereas CERTH׳s tests used air. When experiments with the cardoon 50% w/w–giant reed 50% w/w blend were performed no agglomeration problems were presented. Consequently, gasification could be achieved in higher temperature than that of pure cardoon which led to the reduction of tar concentration.

  2. Direct reduction of hematite powders in a fluidized bed reactor

    Institute of Scientific and Technical Information of China (English)

    Qingshan Zhu; Rongfang Wu; Hongzhong Li

    2013-01-01

    Ultrafine hematite powder was reduced to produce ultrafine iron powder in a 50%Ar-50%H2 atmosphere at 450-550 ℃ in a fluidized bed reactor.The ultrafine hematite powder shows the typical agglomerating fluidization behavior with large agglomerates fluidized at the bottom of the bed and small agglomerates fluidized at the upper part of the bed.It was found that defluidization occurred even at the low temperature of 450 ℃ with low metallization rate.Defluidization was attributed mainly to the sintering of the newly formed iron particles.Granuation was employed to improve the fluidization quality and to tackle the defluidization problem,where granules fluidized like a Geldart's group A powder.Granulation was found to effectively reduce defluidization during reduction,without however sacrificing reduction speed.The asreduced iron powders from both the ultrafine and the granulated hematite exhibited excellent sintering activity,that is,fast sintering at temperature of as low as ~580 ℃,which is much superior as compared to that of nano/ultrafine iron powders made by other processes,

  3. Research into Biomass and Waste Gasification in Atmospheric Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Skala, Zdenek; Ochrana, Ladislav; Lisy, Martin; Balas, Marek; Kohout, Premysl; Skoblja, Sergej

    2007-07-01

    Considerable attention is paid in the Czech Republic to renewable energy sources. The largest potential, out of them all, have biomass and waste. The aim therefore is to use them in CHP in smaller units (up to 5MWel). These are the subject of the research summarized in our article. The paper presents results of experimental research into gasification in a 100 kW AFB gasifier situated in Energy Institute, Faculty of Mechanical Engineering, Brno University of Technology, and fitted with gas cleaning equipment. Within the research, study was carried out into gas cleaning taking primary measures in the fluidized bed and using hot filter, metal-based catalytic filter, and wet scrubber. Descriptions and diagrams are given of the gasifier and new ways of cleaning. Results include: Impact of various fuels (farming and forest wastes and fast-growing woods and culm plants) on fuel gas quality. Individual kinds of biomass have very different thermal and physical properties; Efficiency of a variety of cleaning methods on content of dust and tars and comparison of these methods; and, Impact of gasifier process parameters on resultant gas quality. (auth)

  4. Sorption-enhanced steam methane reforming in fluidized bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Kim

    2006-10-15

    Hydrogen is considered to be an important potential energy carrier; however, its advantages are unlikely to be realized unless efficient means can be found to produce it without generation of CO{sub 2}. Sorption-enhanced steam methane reforming (SE-SMR) represent a novel, energy-efficient hydrogen production route with in situ CO{sub 2} capture, shifting the reforming and water gas shift reactions beyond their conventional thermodynamic limits. The use of fluidized bed reactors for SE-SMR has been investigated. Arctic dolomite, a calcium-based natural sorbent, was chosen as the primary CO{sub 2}-acceptor in this study due to high absorption capacity, relatively high reaction rate and low cost. An experimental investigation was conducted in a bubbling fluidized bed reactor of diameter 0.1 m, which was operated cyclically and batch wise, alternating between reforming/carbonation conditions and higher-temperature calcination conditions. Hydrogen concentrations of >98 mole% on a dry basis were reached at 600 C and 1 atm, for superficial gas velocities in the range of {approx}0.03-0.1 m/s. Multiple reforming-regeneration cycles showed that the hydrogen concentration remained at {approx}98 mole% after four cycles. The total production time was reduced with an increasing number of cycles due to loss of CO{sub 2}-uptake capacity of the dolomite, but the reaction rates of steam reforming and carbonation seemed to be unaffected for the conditions investigated. A modified shrinking core model was applied for deriving carbonation kinetics of Arctic dolomite, using experimental data from a novel thermo gravimetric reactor. An apparent activation energy of 32.6 kj/mole was found from parameter fitting, which is in good agreement with previous reported results. The derived rate expression was able to predict experimental conversion up to {approx}30% very well, whereas the prediction of higher conversion levels was poorer. However, the residence time of sorbent in a continuous

  5. Olive cake combustion in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Topal, H.; Durmaz, A. [Gazi Univ, Ankara (Turkey). Dept. of Mechanical Engineering; Atimtay, A.T. [Middle East Technical Univ., Ankara (Turkey). Dept. of Environmental Engineering

    2002-07-01

    This paper presents the results of a study in which an environmentally sound technology was developed for biomass usage for energy production in Turkey. A circulating fluidized bed of 125 mm diameter and 1,800 mm height was used to determine the combustion characteristics of olive cake (OC) produced in Turkey. Olive cake, an olive oil milling waste product, is available in large amounts at a very low cost. Efficient use of OC in energy production solves the problem of waste management and contributes to meeting targets of the Kyoto Protocol. In this study, olive cake alone and olive cake plus lignite mixtures were burned in separate experiments and in various ratios. A new feeding mechanism was developed to feed the olive cake to the bed. On-line concentrations of oxygen, sulphur dioxide, carbon dioxide, carbon monoxide, nitrogen oxides and total hydrocarbons were measured in the flue gas along with temperature distribution in the bed. Emissions were compared with national standards and combustion efficiency of the olive cake plus lignite coal mixtures and olive cake alone were calculated. The optimum operating parameters were described. OC burned with 94 to 98.5 per cent efficiency. The combustion efficiency increased with increased excess air ratio because volatiles released from the fuel were burned more completely. 3 refs., 5 tabs., 6 figs.

  6. Gasification process of refuse derived fuel in circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, S.; Kinoshita, Y.; Lee, C.W.; Itaya, Y.; Mori, S. [Nagoya Univ., Nagoya (Japan). Dept. of Chemical Engineering

    2002-07-01

    This paper presents a fuel gas production system involving gasification of refuse-derived fuel (RDF) in a circulating fluidized bed (CFB). Although RDF is considered to be a viable source of energy, combustion of RDF has not spread widely because of a lack of conventional incinerators, erosion due to hydrogen chloride, and emissions of dioxin. This paper presents the results of an experimental study of the pyrolysis behaviour of 3 kinds of RDF and the particle motion in a cold model CFB. The objective was to clarify operating parameters for optimum control. It was shown that an increase in combustion temperature improves the yield of the combustible gas components and the energy recycling efficiency from the RDF. The highest heating value of pyrolysis gas was obtained at 873 to 973 degrees K. The gas flow rate in the pneumatic valve of the CFB was an important control factor for the circulation flux and solids holdup in the riser. High holdups were observed when minute silica sand particles were used in the CFB. 15 refs., 1 tab., 8 figs.

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

    Science.gov (United States)

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

    2014-08-26

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

  8. Combined-cycle power stations using ``clean-coal-technologies``: Thermodynamic analysis of full gasification vs. fluidized bed combustion with partial gasification

    Energy Technology Data Exchange (ETDEWEB)

    Lozza, G.; Chiesa, P. [Politecnico di Milano, Milan (Italy). Dept. of Energetics; DeVita, L. [Eniricerche, Milan (Italy)

    1994-12-31

    A novel class of power plants for clean conversion of coal into power has been recently proposed, based on the concept of partial coal gasification and fluidized-bed combustion of unconverted char from gasification. This paper focuses on the thermodynamic aspects of these plants, in comparison with full gasification cycles, assessing their performance on the basis of a common advanced power plant technology level. Several plant configurations are considered, including pressurized or atmospheric fluidized-bed, air- or steam-cooled, with different carbon conversion in the gasifier. The calculation method, used for reproducing plant energy balances and for performance prediction, is described in the paper. A complete second-law analysis is carried out, pointing out the efficiency loss breakdown for both technologies. Results show that partial gasification plants can achieve efficiencies consistently higher than IGCC, depending on plant configuration and carbon conversion, making this solution a viable and attractive option for efficient coal utilization.

  9. Combined-cycle power stations using clean-coal technologies: Thermodynamic analysis of full gasification versus fluidized bed combustion with partial gasification

    Energy Technology Data Exchange (ETDEWEB)

    Lozza, G.; Chiesa, P. [Politecnico di Milano, Milan (Italy). Dept. of Energetics; DeVita, L. [Eniricerche, Milan (Italy)

    1996-10-01

    A novel class of power plants for clean conversion of coal into power has been recently proposed, based on the concept of partial coal gasification and fluidized-bed combustion of unconverted char from gasification. This paper focuses on the thermodynamic aspects of these plants, in comparison with full gasification cycles, assessing their performance on the basis of a common advanced power plant technology level. Several plant configurations are considered, including pressurized or atmospheric fluidized-bed, air- or steam-cooled, with different carbon conversion in the gasifier. The calculation method, used for reproducing plant energy balances and for performance prediction, is described in the paper. A complete second-law analysis is carried out, pointing out the efficiency loss breakdown for both technologies. Results show that partial gasification plants can achieve efficiencies consistently higher than IGCC, depending on plant configuration and carbon conversion, making this solution a viable and attractive option for efficient coal utilization.

  10. Selection of Type I and Type II Methanotrophic Proteobacteria in a Fluidized Bed Reactor under Non-Sterile Conditions

    Science.gov (United States)

    2011-08-01

    00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Selection of Type I and Type II methanotrophic proteobacteria in a fluidized bed reactor under...laboratory- scale fluidized bed reactor was initially inoculated with a Type II Methylocystis-like dominated culture. At elevated levels of dissolved...personal copy Selection of Type I and Type II methanotrophic proteobacteria in a fluidized bed reactor under non-sterile conditions Andrew R. Pfluger a, Wei

  11. Bed-inventory Overturn Mechanism for Pant-leg Circulating Fluidized Bed Boilers

    CERN Document Server

    Wang, Zhe; Yang, Zhiwei; West, Logan; Li, Zheng

    2011-01-01

    A numerical model was established to investigate the lateral mass transfer as well as the mechanism of bed-inventory overturn inside a pant-leg circulating fluidized bed (CFB), which are of great importance to maintain safe and efficient operation of the CFB. Results show that the special flow structure in which the solid particle volume fraction along the central line of the pant-leg CFB is relative high enlarges the lateral mass transfer rate and make it more possible for bed inventory overturn. Although the lateral pressure difference generated from lateral mass transfer inhibits continuing lateral mass transfer, providing the pant-leg CFB with self-balancing ability to some extent, the primary flow rate change due to the outlet pressure change often disable the self-balancing ability by continually enhancing the flow rate difference. As the flow rate of the primary air fan is more sensitive to its outlet pressure, it is easier to lead to bed inventory overturn. While when the solid particle is easier to c...

  12. Fluidized Bed Membrane Reactors for Ultra Pure H₂ Production--A Step forward towards Commercialization.

    Science.gov (United States)

    Helmi, Arash; Fernandez, Ekain; Melendez, Jon; Pacheco Tanaka, David Alfredo; Gallucci, Fausto; van Sint Annaland, Martin

    2016-03-19

    In this research the performance of a fluidized bed membrane reactor for high temperature water gas shift and its long term stability was investigated to provide a proof-of-concept of the new system at lab scale. A demonstration unit with a capacity of 1 Nm³/h of ultra-pure H₂ was designed, built and operated over 900 h of continuous work. Firstly, the performance of the membranes were investigated at different inlet gas compositions and at different temperatures and H₂ partial pressure differences. The membranes showed very high H₂ fluxes (3.89 × 10(-6) mol·m(-2)·Pa(-1)·s(-1) at 400 °C and 1 atm pressure difference) with a H₂/N₂ ideal perm-selectivity (up to 21,000 when integrating five membranes in the module) beyond the DOE 2015 targets. Monitoring the performance of the membranes and the reactor confirmed a very stable performance of the unit for continuous high temperature water gas shift under bubbling fluidization conditions. Several experiments were carried out at different temperatures, pressures and various inlet compositions to determine the optimum operating window for the reactor. The obtained results showed high hydrogen recovery factors, and very low CO concentrations at the permeate side (in average hydrogen can be directly fed to a low temperature PEM fuel cell.

  13. Fluidized Bed Membrane Reactors for Ultra Pure H2 Production—A Step forward towards Commercialization

    Directory of Open Access Journals (Sweden)

    Arash Helmi

    2016-03-01

    Full Text Available In this research the performance of a fluidized bed membrane reactor for high temperature water gas shift and its long term stability was investigated to provide a proof-of-concept of the new system at lab scale. A demonstration unit with a capacity of 1 Nm3/h of ultra-pure H2 was designed, built and operated over 900 h of continuous work. Firstly, the performance of the membranes were investigated at different inlet gas compositions and at different temperatures and H2 partial pressure differences. The membranes showed very high H2 fluxes (3.89 × 10−6 mol·m−2·Pa−1·s−1 at 400 °C and 1 atm pressure difference with a H2/N2 ideal perm-selectivity (up to 21,000 when integrating five membranes in the module beyond the DOE 2015 targets. Monitoring the performance of the membranes and the reactor confirmed a very stable performance of the unit for continuous high temperature water gas shift under bubbling fluidization conditions. Several experiments were carried out at different temperatures, pressures and various inlet compositions to determine the optimum operating window for the reactor. The obtained results showed high hydrogen recovery factors, and very low CO concentrations at the permeate side (in average <10 ppm, so that the produced hydrogen can be directly fed to a low temperature PEM fuel cell.

  14. Materials problems in fluidized-bed combustion systems: effect of process variables on in-bed corrosion. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Minchener, A.J.; Rogers, E.A.; LaNauze, R.D.

    1980-08-01

    The influence of operating conditions in a coal fired fluidized bed combustor on the rate of fireside corrosion of air cooled heat exchanger tubes, with metal temperatures in the range 540/sup 0/C to 900/sup 0/C, has been investigated. Four 250 hour tests were carried out on a 0.3 m square atmospheric pressure fluidized bed combustor operating with a fluidizing velocity of 0.9 ms/sup -1/, 10 to 20% excess air and bed temperatures of 850/sup 0/C and 900/sup 0/C. The feed coal was Illinois No. 6 which was used both with and without the addition of limestones to suppress the emission of sulfur oxides. A test without the addition of limestone showed very little corrosive attack of any metal components. Tests with the addition of limestone showed a range of corrosive attack. In general, where different alloy types were exposed at the same metal temperature, the iron based austenitic steels showed a better corrosion resistance than the nickel based alloys. This result strongly supports the model for the corrosion which has been developed as a result of the earlier investigations. This model postulates that local regions of low oxygen activity exist in the system, and, in the presence of calcium sulfate, these result in the generation of high local sulfur activities. The combination of low oxygen and high sulfur activities leads to sulfidation of sensitive alloys.

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

    Science.gov (United States)

    Sun, May Yongmei

    This research focuses on two steps of commercial fuel ethanol production processes: the hydrolysis starch process and the fermentation process. The goal of this research is to evaluate the performance of co-immobilized biocatalysts in a fluidized bed reactor with emphasis on economic and engineering aspects and to develop a predictive mathematical model for this system. The productivity of an FBR is higher than productivity of a traditional batch reactor or CSTR. Fluidized beds offer great advantages over packed beds for immobilized cells when small particles are used or when the reactant feed contains suspended solids. Plugging problems, excessive pressure drops (and thus attrition), or crushing risks may be avoided. No mechanical stirring is required as mixing occurs due to the natural turbulence in the fluidized process. Both enzyme and microorganism are immobilized in one catalyst bead which is called co-immobilization. Inside this biocatalyst matrix, starch is hydrolyzed by the enzyme glucoamylase to form glucose and then converted to ethanol and carbon dioxide by microorganisms. Two biocatalysts were evaluated: (1) co-immobilized yeast strain Saccharomyces cerevisiae and glucoamylase. (2) co-immobilized Zymomonas mobilis and glucoamylase. A co-immobilized biocatalyst accomplishes the simultaneous saccharification and fermentation (SSF process). When compared to a two-step process involving separate saccharification and fermentation stages, the SSF process has productivity values twice that given by the pre-saccharified process when the time required for pre-saccharification (15--25 h) was taken into account. The SSF process should also save capital cost. The information about productivity, fermentation yield, concentration profiles along the bed, ethanol inhibition, et al., was obtained from the experimental data. For the yeast system, experimental results showed that: no apparent decrease of productivity occurred after two and half months, the productivity

  16. Effect of Liquid Viscosity and Solid Inventory on Hydrodynamics in a Liquid - solid Circulating Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Nirmala sundaram

    2017-01-01

    Full Text Available A comprehensive hydrodynamic study of a Liquid - Solid Circulating Fluidized Bed (LSCFB is conducted with changes in viscosity of the fluidizing medium and the inventory height of solids initially fed into the system. An LSCFB of height 2.95m and riser outer diameter 0.1m was chosen for experimentation. The three liquid media systems with varying viscosities that were chosen were water, glycerol 10% (v/v and glycerol 20% (v/v. Effect of inventory on the hydrodynamics was also studied, by taking initial heights of inventory to be 15cm, 25cm and 35cm. The hydrodynamic studies concentrated on pressure gradients along the axial pressure tapings, axial solid holdup, average solid holdup, solid circulation rate and slip velocity. Uniformity in axial solid holdup and average solid holdup was validated for changes in viscosity and inventory. Solid flux was seen to follow an inverse relationship to holdup. The changes in slip velocity with varying viscosity and inventory were studied, and found to decrease with both variables. The distribution parameter, Co of the drift flux model was found to be in the range of 0.983-0.994, suggesting non-uniformity in radial solid distribution, with higher solid concentration by the walls compared to the core of the column.

  17. Olive cake combustion in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Huseyin Topal; Aysel T. Atimtay; Ali Durmaz [Gazi University, Ankara (Turkey). Department of Mechanical Engineering, Engineering and Architecture Faculty

    2003-06-01

    In this study, a circulating fluidized bed of 125 mm diameter and 1800 mm height was used to find the combustion characteristics of olive cake (OC) produced in Turkey. A lignite coal that is most widely used in Turkey was also burned in the same combustor. The combustion experiments were carried out with various excess air ratios. The excess air ratio, {lambda} has been changed between 1.1 and 2.16. Temperature distribution along the bed was measured with thermocouples. On-line concentrations of O{sub 2}, SO{sub 2}, CO{sub 2}, CO, NOx and total hydrocarbons were measured in the flue gas. Combustion efficiencies of OC and lignite coal are calculated, and the optimum conditions for operating parameters are discussed. The combustion efficiency of OC changes between 82.25 and 98.66% depending on the excess air ratio. There is a sharp decrease observed in the combustion losses due to hydrocarbons and CO as the excess air ratio increases. The minimum emissions are observed at {lambda} = 1.35. Combustion losses due to unburned carbon in the bed material do not exceed 1.4 wt% for OC and 1.85 wt% for coal. The combustion efficiency for coal changes between 82.25 and 98.66% for various excess air ratios used in the study. The ash analysis for OC is carried out to find the suitability of OC ash to be used as fertilizer. The ash does not contain any hazardous metal. 7 refs., 10 figs., 6 tabs.

  18. Hydrodynamics of a hybrid circulating fluidized bed reactor with a partitioned loop seal system

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Dal-Hee; Moon, Jong-Ho; Jin, Gyoung Tae; Shun, Dowon [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Yun, Minyoung; Park, Chan Seung; Norbeck, Joseph M. [University of California, Riverside (United States)

    2015-07-15

    A circulating fluidized bed (CFB) with a hybrid design has been developed and optimized for steam hydrogasification. The hybrid CFB is composed of a bubbling fluidized bed (BFB) type combustor and a fast fluidized bed (FB) type gasifier. Char is burnt in the combustor and the generated heat is supplied to the gasifier along with the bed materials. Two different types of fluidized beds are connected to each other with a newly developed partitioned loop seal to avoid direct contact between two separate gas streams flowing in each fluidized bed. Gas mixing tests were carried out with Air and Argon in a cold model hybrid CFB to test the loop seal efficiency. Increase in solid inventory in the loop seal can improve the gas separation efficiency. It can be realized at higher gas velocity in fast bed and with higher solid inventory in the loop seal system. In addition, bed hydrodynamics was investigated with varying gas flow conditions and particle sizes in order to obtain a full understanding of changes of solid holdup in the FB. The solid holdup in the FB increased with increasing gas velocity in the BFB. Conversely, increase in gas velocity in the FB contributed to reducing the solid holdup in the FB. It was observed that changing the particle size of bed material does not have a big impact on hydrodynamic parameters.

  19. Experimental Study on Coal Multi-generation in Dual Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    Fan Xiaoxu; Lu Qinggang; Na Yongjie; Liu Qi

    2007-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-04-01

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

  1. Bench scale demonstration of the Supermethanol concept : The synthesis of methanol from glycerol derived syngas

    NARCIS (Netherlands)

    van Bennekom, J. G.; Venderbosch, R. H.; Assink, D.; Lemmens, K. P. J.; Heeres, H. J.

    2012-01-01

    An integrated process for the synthesis of methanol from aqueous glycerol involving reforming of the feed to syngas followed by methanol synthesis is successfully demonstrated in a continuous bench scale unit. Glycerol reforming was carried out at pressures of 24-27 MPa and temperatures of 948-998 K

  2. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2015-09-01

    Full Text Available This paper focuses on assessment of the effect of flue gas recirculation (FGR on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  3. Parametric sensitivity analysis to investigate heptane reforming in circulating fast fluidized bed membrane reactors

    Directory of Open Access Journals (Sweden)

    M.E.E. Abashar

    2015-01-01

    Full Text Available In this paper, we present mathematical modeling and numerical simulation tools in searching the high parameter space of steam reforming of heptane for the key design parameters, which have the potential to give high heptane conversion, high hydrogen yield and hydrogen to carbon monoxide ratio within the industrial limits for the syngas used as a feedstock for the gas to liquid processes (GTL. The system under consideration is the novel circulating fast fluidized bed membrane reactor (CFFBMR. The simulation results show that the hydrogen membrane has a significant role in the displacement of the thermodynamic equilibriums of the reversible reactions and production of ultraclean hydrogen, which can be used as a fuel for the fuel cells. Also the results of the sensitivity analysis show that the best performance of the CFFBMR can be obtained by a proper selection of combination of several parameters of high feed temperatures, high steam to carbon feed ratios, high reaction side pressures coupled with a large permeation area of a composite thin film membrane. These parameters are interacting in a very complex manner to give 100% conversion of heptane and 496.94% increase in hydrogen yield compared to the reformer without hydrogen membrane. It was found that under these selected operating conditions a low H2/CO ratio of 1.15 is achieved satisfying the practical recommended industrial range.

  4. Chemical looping reactor system design double loop circulating fluidized bed (DLCFB)

    Energy Technology Data Exchange (ETDEWEB)

    Bischi, Aldo

    2012-05-15

    Chemical looping combustion (CLC) is continuously gaining more importance among the carbon capture and storage (CCS) technologies. It is an unmixed combustion process which takes place in two steps. An effective way to realize CLC is to use two interconnected fluidized beds and a metallic powder circulating among them, acting as oxygen carrier. The metallic powder oxidizes at high temperature in one of the two reactors, the air reactor (AR). It reacts in a highly exothermic reaction with the oxygen of the injected fluidising air. Afterwards the particles are sent to the other reactor where the fuel is injected, the fuel reactor (FR). There, they transport heat and oxygen necessary for the reaction with the injected fuel to take place. At high temperatures, the particle's oxygen reacts with the fuel producing Co2 and steam, and the particles are ready to start the loop again. The overall reaction, the sum of the enthalpy changes of the oxygen carrier oxidation and reduction reactions, is the same as for the conventional combustion. Two are the key features, which make CLC promising both for costs and capture efficiency. First, the high inherent irreversibility of the conventional combustion is avoided because the energy is utilized stepwise. Second, the Co2 is intrinsically separated within the process; so there is in principle no need either of extra carbon capture devices or of expensive air separation units to produce oxygen for oxy-combustion. A lot of effort is taking place worldwide on the development of new chemical looping oxygen carrier particles, reactor systems and processes. The current work is focused on the reactor system: a new design is presented, for the construction of an atmospheric 150kWth prototype working with gaseous fuel and possibly with inexpensive oxygen carriers derived from industrial by-products or natural minerals. It consists of two circulating fluidized beds capable to operate in fast fluidization regime; this will increase the

  5. Study on the flow in the pipelines of the support system of circulating fluidized bed

    Science.gov (United States)

    Meng, L.; Yang, J.; Zhou, L. J.; Wang, Z. W.; Zhuang, X. H.

    2013-12-01

    In the support system of Circulating Fluidized Bed (Below referred to as CFB) of thermal power plant, the pipelines of primary wind are used for transporting the cold air to the boiler, which is important in controlling and combustion effect. The pipeline design will greatly affect the energy loss of the system, and accordingly affect the thermal power plant economic benefits and production environment. Three-dimensional numerical simulation is carried out for the pipeline internal flow field of a thermal power plant in this paper. Firstly three turbulence models were compared and the results showed that the SST k-ω model converged better and the energy losses predicted were closer to the experimental results. The influence of the pipeline design form on the flow characteristics are analysed, then the optimization designs of the pipeline are proposed according to the energy loss distribution of the flow field, in order to reduce energy loss and improve the efficiency of tunnel. The optimization plan turned out to be efficacious; about 36% of the pressure loss is reduced.

  6. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Science.gov (United States)

    Błaszczuk, Artur

    2015-09-01

    This paper focuses on assessment of the effect of flue gas recirculation (FGR) on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB) combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater) and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  7. Fluidized bed coupled rotary reactor for nanoparticles coating via atomic layer deposition.

    Science.gov (United States)

    Duan, Chen-Long; Liu, Xiao; Shan, Bin; Chen, Rong

    2015-07-01

    A fluidized bed coupled rotary reactor has been designed for coating on nanoparticles (NPs) via atomic layer deposition. It consists of five major parts: reaction chamber, dosing and fluidizing section, pumping section, rotary manipulator components, as well as a double-layer cartridge for the storage of particles. In the deposition procedure, continuous fluidization of particles enlarges and homogenizes the void fraction in the particle bed, while rotation enhances the gas-solid interactions to stabilize fluidization. The particle cartridge presented here enables both the fluidization and rotation acting on the particle bed, demonstrated by the analysis of pressure drop. Moreover, enlarged interstitials and intense gas-solid contact under sufficient fluidizing velocity and proper rotation speed facilitate the precursor delivery throughout the particle bed and consequently provide a fast coating process. The cartridge can ensure precursors flowing through the particle bed exclusively to achieve high utilization without static exposure operation. By optimizing superficial gas velocities and rotation speeds, minimum pulse time for complete coating has been shortened in experiment, and in situ mass spectrometry showed the precursor usage can reach 90%. Inductively coupled plasma-optical emission spectroscopy results suggested a saturated growth of nanoscale Al2O3 films on spherical SiO2 NPs. Finally, the uniformity and composition of the shells were characterized by high angle annular dark field-transmission electron microscopy and energy dispersive X-ray spectroscopy.

  8. Fluidized bed coupled rotary reactor for nanoparticles coating via atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Chen-Long; Liu, Xiao; Chen, Rong, E-mail: rongchen@mail.hust.edu.cn, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Shan, Bin, E-mail: rongchen@mail.hust.edu.cn, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China)

    2015-07-15

    A fluidized bed coupled rotary reactor has been designed for coating on nanoparticles (NPs) via atomic layer deposition. It consists of five major parts: reaction chamber, dosing and fluidizing section, pumping section, rotary manipulator components, as well as a double-layer cartridge for the storage of particles. In the deposition procedure, continuous fluidization of particles enlarges and homogenizes the void fraction in the particle bed, while rotation enhances the gas-solid interactions to stabilize fluidization. The particle cartridge presented here enables both the fluidization and rotation acting on the particle bed, demonstrated by the analysis of pressure drop. Moreover, enlarged interstitials and intense gas–solid contact under sufficient fluidizing velocity and proper rotation speed facilitate the precursor delivery throughout the particle bed and consequently provide a fast coating process. The cartridge can ensure precursors flowing through the particle bed exclusively to achieve high utilization without static exposure operation. By optimizing superficial gas velocities and rotation speeds, minimum pulse time for complete coating has been shortened in experiment, and in situ mass spectrometry showed the precursor usage can reach 90%. Inductively coupled plasma-optical emission spectroscopy results suggested a saturated growth of nanoscale Al{sub 2}O{sub 3} films on spherical SiO{sub 2} NPs. Finally, the uniformity and composition of the shells were characterized by high angle annular dark field-transmission electron microscopy and energy dispersive X-ray spectroscopy.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-01

    Currently, several candidates for secondary waste immobilization at the Hanford site in the State of Washington, USA are being considered. To demonstrate the durability of the product in the unsaturated Integrated Disposal Facility (IDF) at the site, a series of tests have been performed one of the candidate materials using the Pressurized Unsaturated Flow (PUF) system. The material that was tested was the Fluidized Bed Steam Reformer (FBSR) granular product and the granular product encapsulated in a geopolymer matrix. The FBSR product is composed primarily of an insoluble sodium aluminosilicate matrix with the dominant phases being feldspathoid minerals mostly nepheline, sodalite, and nosean. The PUF test method allows for the accelerated weathering of materials, including radioactive waste forms, under hydraulically unsaturated conditions, thus mimicking the open-flow and transport properties that most likely will be present at the IDF. The experiments show a trend of decreasing tracer release as a function of time for several of the elements released from the material including Na, Si, Al, and Cs. However, some of the elements, notably I and Re, show a steady release throughout the yearlong test. This result suggests that the release of these minerals from the sodalite cage occurs at a different rate compared with the dissolution of the predominant nepheline phase.

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

    Science.gov (United States)

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

    2009-02-01

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

  11. Gasification of lignocellulosic biomass in fluidized beds for renewable energy development: A review

    Energy Technology Data Exchange (ETDEWEB)

    Alauddin, Zainal Alimuddin Bin Zainal; Lahijani, Pooya [School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Mohammadi, Maedeh; Mohamed, Abdul Rahman [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2010-12-15

    A literature review on gasification of lignocellulosic biomass in various types of fluidized bed gasifiers is presented. The effect of several process parameters such as catalytic bed material, bed temperature and gasifying agent on the performance of the gasifier and quality of the producer gas is discussed. Based on the priorities of researchers, the optimum values of various desired outputs in the gasification process including improved producer gas composition, enhanced LHV, less tar and char content, high gas yield and enhanced carbon conversion and cold gas efficiency have been reported. The characteristics and performance of different fluidized bed gasifiers were assessed and the obtained results from the literature have been extensively reviewed. Survey of literature revealed that several industrial biomass gasification plants using fluidized beds are currently conducting in various countries. However, more research and development of technology should be devoted to this field to enhance the economical feasibility of this process for future exploitations. (author)

  12. Clustering behavior of solid particles in two-dimensional liquid-solid fluidized-beds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, the clustering behavior of solid particles in a two-dimensional (2D) liquid-solid fluidized-bed was studied by using the charge coupled devices (CCD) imaging measuring and processing technique and was characterized by fractal analysis. CCD images show that the distribution of solid particles in the 2D liquid-solid fluidised-bed is not uniform and self-organization behavior of solid particles was observed under the present experimental conditions. The solid particles move up in the 2D fluidized-bed in groups or clusters whose configurations are often in the form of horizontal strands. The box fractal dimension of the cluster images in the 2D liquid-solid fluidized-bed increases with the rising of solid holdup and reduces with the increment of solid particle diameter and superficial liquid velocity. At given solid holdup and solid particle size,the lighter particles show smaller fractal dimensions.

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

    Science.gov (United States)

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

    2011-04-01

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

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

    Science.gov (United States)

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

    2005-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-02-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-10-30

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

  17. [Structure and fluidization of an internally circulating fluidized bed for FGD process].

    Science.gov (United States)

    Yang, Liuchun; Yang, Wenqi; Tong, Zhiquan

    2003-09-01

    A new internally circulating fluidized bed for FGD process was developed, and different types of top and bottom structures were employed in the experiment to find out the best fluidized bed structure. Fluidizing status, the axial distribution of solid hold-up and the fluid mechanics under cold conditions were investigated. The results indicate that the unit can realize internally circulating of a large number of solid particles which presents an core-annulus structure when the velocity of fluidizing gas was at the range of 2.5 to 5 m/s, and that the solid density in the bed is higher than that in traditional equal diameter fluidized bed, which provide the equipment with potential for application in FGD process.

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tingwen [URS Corporation; Morgantown, WV (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Benyahia, Sofiane [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2013-10-01

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

  19. An Experimental Investigation on the Drying of Sliced Food Products in Centrifugal Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    M.H.Shi; Y.L.Hao; 等

    1998-01-01

    An experimental investigation on the fluidization and drying characteristics of sliced food products in a centrifugal fluidized bed dryer was carried out,The rotaing speed ranges from 300 rpm to 500 rpm.Sliced potato and radish were used as the testing materials.The results show that the sliced materials can be fluidized well in the centrifugal fluidized bed.The fluidized curve has a maximum value and the critical fluidized velocities vary with the type of the test material,its shape and dimension as well as operating parameters.The sliced food materials can be dried very well and fast in the centrifugal fluidized bed with a large productivity.The factors that influence the drying process were examined and discussed.The final shape and inner structure of the dried products were observed.The water recovery characteristics of the drried products were also investigated.

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

    Science.gov (United States)

    You, Changfu; Xu, Xuchang

    2008-04-01

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

  1. Characterization of Biofilm in 200W Fluidized Bed Reactors

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-29

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

  2. Performances of continuous dryer with inert medium fluidized bed

    Directory of Open Access Journals (Sweden)

    Arsenijević Zorana Lj.

    2008-01-01

    Full Text Available A fluid bed dryer with inert particles represents a very attractive alternative to other drying technologies according to the main efficiency criteria, i.e. specific water evaporation rate, specific heat consumption and speci­fic air consumption. A high drying efficiency results from the large con­tact area and from the large temperature difference between the inlet and outlet air. A rapid mixing of the particles leads to nearly isothermal conditions throughout the bed. A fluid bed dryer with inert particles was used for drying of slurries. Experiments were performed in a cylindrical column 215 mm in diameter with glass spheres as inert particles. In this paper, results of drying experi­ments with slurries of Zineb fungicide, copper hydroxide, calcium carbo­nate and pure water used as the feed material are presented. In our fluidized bed we successfully dried a number of other materials such as: fungicides and pesticides (Ziram, Propineb, Mangozeb, copper oxy-chloride, copper oxy-sulphate, Bordeaux mixture, other inorganic compounds (calcium sulphate, cobalt carbonate, electrolytic copper, sodium chloride, and a complex compound (organo-bentonite. The effects of operating conditions on dryer throughput and product quality were investigated. Main performance criteria, i.e. specific water evaporation rate, specific heat consumption and specific air consumption, were quantified. Temperature profile along the bed was mapped, and nearly isothermal conditions were found due to thorough mixing of the particles. Analysis of drying and energy efficiencies as a function of inlet and outlet air temperature difference was performed for deeper insight in dryer behavior and for optimizing dryer design and operation from an energy point of view. A simple mathematical model based on an overall heat balance predicts the dryer performance quite well. The industrial prototype with fluid bed of 0.8 m in diameter and capacity 650 kg of evaporated moisture per

  3. Characterization of biofilm in 200W fluidized bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Michelle H. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Saurey, Sabrina D. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lee, Brady D. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Parker, Kent E. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Eisenhauer, Emalee E. R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Cordova, Elsa A. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Golovich, Elizabeth C. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

    2014-09-29

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

  4. Comparison of fibre optical measurements and discrete element simulations for the study of granulation in a spout fluidized bed

    NARCIS (Netherlands)

    Link, J.M.; Godlieb, W.; Tripp, P.; Deen, N.G.; Heinrich, S.; Kuipers, J.A.M.; Schönherr, M.; Peglow, M.

    2009-01-01

    Spout fluidized beds are frequently used for the production of granules or particles through granulation. The products find application in a large variety of applications, for example detergents, fertilizers, pharmaceuticals and food. Spout fluidized beds have a number of advantageous properties, su

  5. 生物质鼓泡流化床和循环流化床气化对比试验%Comparison of Bubbling Fluidized Bed and Circulating Fluidized Bed in Gasification of Biomass

    Institute of Scientific and Technical Information of China (English)

    范晓旭; 贤建伟; 初雷哲; 杨立国

    2011-01-01

    在内径为φ0.2 m、高6 m的流化床装置上,利用两种不同粒径的石英砂,分别进行了高速鼓泡流化床(BFB)和循环流化床(CFB)的冷态压力分布试验和热态气化试验.结果表明:冷态试验中,鼓泡流化床压力分布主要集中在底部的密相区,循环流化床压力分布更趋均匀.热态稳定气化阶段,循环流化床轴向温差只有40℃,气化的燃气热值、碳转化率和气化效率均高于鼓泡流化床.%The results from biomass gasification in a pilot-scale (6m tall × 0. 2 m internal diameter) air-blown circulating fluidized bed gasifier was tested and compared with bubbling fluidized bed gasifier. The results showed that the diameters of bed material in bubbling fluidized bed and circulating fluidized bed were different. The bubbling fluidized bed had a dense zone and bed material was homogeneous distribution in circulating fluidized bed. The temperature of the circulating fluidized bed was more uniform than bubbling fluidized bed. The carbon conversion rate, gasification efficiency and low gas heat value of circulating fluidized bed were larger than that of bubbling fluidized bed gasifier.

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

    Science.gov (United States)

    Hannula, Ilkka; Kurkela, Esa

    2010-06-01

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

  7. Control of the Bed Temperature of a Circulating Fluidized Bed Boiler by using Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    AYGUN, H.

    2012-05-01

    Full Text Available Circulating fluidized bed boilers are increasingly used in the power generation due to their higher combustion efficiency and lower pollutant emissions. Such boilers require an effective control of the bed temperature, because it influences the boiler combustion efficiency and the rate of harmful emissions. A Particle-Swarm-Optimization-Proportional-Integrative-Derivative (PSO-PID controller for the bed temperature of a circulating fluidized bed boiler is presented. In order to prove the capability of the proposed controller, its performances are compared at different boiler loads with those of a Fuzzy Logic (FL controller. The simulation results demonstrate some advantages of the proposed controller.

  8. Experiment research on grain drying process in the heat pump assisted fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Jing Yang; Li Wang; Fi Xiang; Lige Tong; Hua Su

    2004-01-01

    A heat pump assisted fluidized bed grain drying experimental system was developed. Based on this system, a serial of experiments was performed under four kinds of air cycle conditions. According to the experimental analysis, an appropriate drying medium-air cycle for the heat pump assisted fluidized bed drying equipment was decided, which is different from the commonly used heat pump assisted drying system. The experimental results concerning the drying operation performance of the new system show that the averaged coefficient of performance (COP) can reach more than 2.5. The economical evaluation was performed and the powefficiency and great application potentiality in future market.

  9. Application of fluidized-bed technology to the recovery of waste heat

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, G.J.; Grogan, P.J.; Evans, A.R.

    1979-08-01

    The fluidized-bed, waste-heat boiler (FBWHB) may represent a significant opportunity for industrial energy conservation. The applications of FBWHBs to the recovery of heat from waste streams are examined. Compared to other waste-heat recovery units, FBWHBs can transfer more heat per unit volume and are physically smaller - an important consideration for retrofit and construction costs. A detailed discussion of fluidized beds, including their application in waste-heat recovery and the factors affecting FBWHB design is presented. Design methodology is discussed along with a preliminary engineering design for recovering heat from a waste-gas stream, a typical FBWHB application.

  10. Low Density Dry Coal Beneficiation Using an Air Dense Medium Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    LUO Zhen-fu; ZHU Jian-feng; FAN Mao-ming; ZHAO Yue-min; TAO Xiu-xiang

    2007-01-01

    For the production of low ash content clean coal, separation at low density is required for some raw coals. Based on analyzing the fluidizing characteristics of magnetic pearls with a specific size distribution and formation mechanism of a microbubble fluidized bed, optimal technological and operating parameters suitable for low density coal separation were determined. The experimental results show that an air dense medium fluidized bed with low density can be formed using magnetic pearls as medium solids, which can efficiently beneficiate coal of 6-50 mm size with a probable error Ep value of 0.05 at a separating density of 1.44 g/cm3.

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

    Science.gov (United States)

    Kim, Sung Won

    2015-01-01

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

  12. Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Åmand, Lars-Erik; Dam-Johansen, Kim;

    1996-01-01

    The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O in the comb......The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O...

  13. RADIAL PROFILE OF THE SOLID FRACTION IN A LIQUID-SOLID CIRCULATING FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Tiefeng Wang; Jinfu Wang; Jing Lin; Yong Jin

    2003-01-01

    @@ Liquid-solid circulating fluidized beds have a number of attractive features suitable for processes where liquid-solid contact is important (Liang et al., 1996; Zhang et al., 2002).Liang et al. (1996) and Zheng et al. (2002) studied the radial profile of the solid fraction in the liquid-solid circulating fluidization regime and found that it is not uniform, unlike the conventional liquid-solid fluidized bed. This non-uniformity can affect reactant concentration distribution, mass transfer and ultimately reactant conversion.Therefore, information on the radial flow structure is crucial to reactor design and process optimization.

  14. Modeling the injection of gas-liquid jets into fluidized bed of fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Aryiapadi, S.; Berutti, F.; Briens, C.; Hulet, C. [Western Ontario University, Dept. of Chemical and Biochemical Engineeering, London, ON (Canada); Griffith, P. [Massachussetts Institute of Technology, Dept. of Mechanical Engineering, Cambridge, MA (United States)

    2003-08-01

    A simplified momentum-based approach to calculate the solid entrainment rate into a gas-liquid jet injected into a fluidized bed is described. The model is verified by a recently developed experimental technique. The paper also addresses correction factors to the initial momentum calculated from the homogenous model. The solids entrainment rates predicted by the model were found to be very close to experimentally obtained values. It is suggested that the model can be usefully employed in characterizing the behaviour of gas-liquid jets injected into fluidized beds of fine particles. 21 refs., 8 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, R.Q.

    1989-11-01

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

  16. Thorium utilization program. Quarterly progress report for the period ending November 30, 1975. [Fuel element crushing, solids handling, fluidized bed combustion, aqueous separations, solvent extraction, systems design and drafting, alternative head-end reprocessing, and fuel recycle systems analysis

    Energy Technology Data Exchange (ETDEWEB)

    1975-12-31

    The development program for HTGR fuel reprocessing continues to emphasize the design and construction of a prototype head-end line. Design work on the multistage crushing system, the primary and secondary fluidized bed burners, the pneumatic transfer systems, and the ancillary fixtures for semiremote assembly and disassembly is essentially complete. Fabrication and receipt of all major components is under way, and auxiliary instrumentation and support systems are being installed. Studies of flow characteristics of granular solids in pneumatic transfer systems are continuing and data are being collected for use in design of systems for solids handling. Experimental work on the 20-cm primary fluidized bed burner verified the fines recycle operating mode in runs of greater than 24 hr. Twelve leaching runs were performed during the quarter using crushed, burned-back TRISO coated ThC/sub 2/ particles and burned-back BISO coated sol gel ThO/sub 2/ particles to examine the effect of varying the Thorex-to-thoria ratio to give product solutions ranging from 0.25M to 1M in thorium. Only minor effects were observed and reference values for facility operations were specified. Two-stage leaching runs with burned-back ThC/sub 2/ indicate there are no measurable differences in total dissolution time as compared to single-stage leaching. Bench-scale tests on oxidation of HTGR fuel boron carbide at 900/sup 0/C indicates that most if not all of the carbide will be converted to boron oxide in the fluidized bed burner. Eight solvent extraction runs were completed during the quarter. These runs represented the first cycle and second uranium cycle of the acid-Thorex flowsheet. A detailed calculation of spent fuel compositions by fuel block and particle type is being performed for better definition of process streams in a fuel reprocessing facility.

  17. 磁场流化床在生化工程中的应用%Application of Magnetically Fluidized Beds in Biochemical Engineering

    Institute of Scientific and Technical Information of China (English)

    吕秀菊; 曲红波; 丛威; 欧阳藩

    2001-01-01

    This paper presents a review of applications of the magnetically fluidized beds (MFB) in biochemical engineering. MFB is formed when introducing a magnetic field into a fluidized bed which is filled with magnetically susceptible particles as bed matrix. This enables MFB an extensive operating range and good adaptability. In particular, magnetically stabilized fluidized bed (MSFB), which is formed at certain magnetic strength and fluid velocity of MFB, provides good solid-liquid contact character of packed bed yet maintains fluidized bed virtue of low pressure drop and high efficiency of mass transfer and heat transfer. MFB has now been used in immobilized bioreactors, solid-liquid separation of fermentation, continuous affinity chromatography, cell separation in immunology and culture of plant cells and yeast. In this paper, the theory and characteristics of MFB are introduced. Emphasis is put on current achievements and applications in biochemical engineering of MFB. The prospects and difficulties for wide using of MFB are also described.%磁场流化床(Magnetically Fluidized Bed, 以下简称MFB)是将磁场引入普通流化床,采用磁敏性颗粒为床层介质的流固相处理系统。MFB利用磁场调节颗粒和流体的运动,使流化床具有更宽的操作范围和适应性。其中,在一定磁场和流动条件下形成的磁稳定流化床(Magnetically Stabilized Fluidized Bed,以下简称MSFB)更是兼有固定床的流固接触特性和流化床的压降低、传热传质效率高的优点,操作范围较普通流化床变宽。磁场流化床在生化工程领域已经应用于固定化生物反应器,发酵液固液分离,连续亲合色谱,细胞分离,以及植物细胞和酵母细胞培养等过程。本文介绍了磁场流化床的基本原理和特性及其在生化工程中的应用情况,并分析了该技术进一步应用所面临的困难和发展前景。

  18. Hydrodynamic study of the turbulent fluidized beds; Etude hydrodynamique des lits fluidises turbulents

    Energy Technology Data Exchange (ETDEWEB)

    Taxil, I.

    1996-12-20

    Gas-solid turbulent fluidization has already been widely studied in the literature. However, its definition and specificities remain controversial and confused. Most of the studies focussed on the turbulent transition velocities are based on wall pressure drop fluctuations studies. In this work, we first characterize the turbulent regime with the classical study of pressure drop signals with standard deviation analysis, completed with a more specific frequency analysis and also by a stochastic analysis. Then, we evaluate bubble flow properties. Experimental results have been obtained in a 0.2 m I.D. fluidized bed expanding to 0.4 m I.D. in the freeboard in order to limit entrainment at high fluidization velocities. The so lid used was FCC catalyst. It was fluidized by air at ambient conditions. The superficial fluidization velocity ranged 0.2 to 2 m/s. Fast response transducers recorded pressure drop at the wall and bubble flow properties (bubble size, bubble velocity and bubble frequency) could be deduced from a light reflected signal at various bed locations with optical fibers. It has been shown the turbulent regime is delimited by two velocities: Uc (onset of turbulent regime) and Utr (onset of transport regime), which can be determined based on standard deviations, dominant frequencies and width of wave land of pressure signals. The stochastic analysis confirms that the signal enriches in frequencies in the turbulent regime. Bubble size and bubble velocity could be correlated to the main superficial gas velocity. The main change in bubble flow in the turbulent regime was shown to be the stagnation of the bubble frequency at its maximum value. It was also shown that the bubble flow properties in the turbulent regime imply a strong aeration of the emulsion phase. (authors) 76 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nsakala ya Nsakala; Gregory N. Liljedahl

    2003-05-15

    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.

  20. Foaming phenomenon in bench-scale anaerobic digesters.

    Science.gov (United States)

    Siebels, Amanda M; Long, Sharon C

    2013-04-01

    The Madison Metropolitan Sewerage District (The District) in Madison, Wisconsin has been experiencing seasonal foaming in their anaerobic biosolids digesters, which has occurred from mid-November to late June for the past few years. The exact cause(s) of foaming is unknown. Previous research findings are unclear as to whether applications of advanced anaerobic digestion processes reduce the foaming potential of digesters. The object of this study was to investigate how configurations of thermophilic and acid phase-thermophilic anaerobic digestion would affect foaming at the bench-scale level compared to single stage mesophilic digestion for The District. Bench-scale anaerobic digesters were fed with a 4 to 4.5% by dry weight of solids content blend of waste activated sludge (WAS) and primary sludge from The District. Foaming potential was monitored using Alka-Seltzer and aeration foaming tests. The bench-scale acid phase-thermophilic digester had a higher foaming potential than the bench-scale mesophilic digester. These results indicate that higher temperatures increase the foaming potential of the bench-scale anaerobic digesters. The bench-scale acid phase-thermophilic digesters had a greater percent (approximately 5 to 10%) volatile solids destruction and a greater percent (approximately 5 to 10%) total solids destruction when compared to the bench-scale mesophilic digester. Overall, for the full-scale foaming experienced by The District, it appears that adding an acid phase or switching to thermophilic digestion would not alleviate The District's foaming issues.

  1. Bench-Scale Co-Processing

    Energy Technology Data Exchange (ETDEWEB)

    Piasecki, C.A.; Gatsis, J.G.; Fullerton, H.E.

    1993-11-08

    This topical report is the first for the UOP Bench-Scale Co-processing contract. The objective of this contract is to extend and optimize the UOP single-stage, slurry-catalyzed co-processing scheme. UOP co-processing uses a single-stage, slurry-catalyzed scheme in which petroleum vacuum resid and coal are simultaneously upgraded to a high-quality synthetic oil. A highly active, well-dispersed catalyst permits operations at moderate- and high-severity reaction conditions with minimum detrimental thermal reactions. In this process, finely ground coal, petroleum resid, and catalyst are mixed, combined with hydrogen, and then directed to a single-stage reactor, where the simultaneous upgrading of the petroleum resid and coal occurs. The reactor effluent is directed to a series of separators, where a hydrogen-rich gas is recovered and recycled back to the reactor inlet. The balance of the material is sent to a series of separators, where the light gasses, light oil, vacuum gas on (VGO), catalyst, unconverted coal, ash, and residues are recovered. The catalyst is recycled back to the reactor. The UOP co-processing scheme is designed to be integrated into a conventional petroleum refinery. the hydrocarbon products from the co-processing unit will be sent to the refinery for final upgrading to finished products. A major focus of this contract is to investigate ways to reduce the catalyst and catalyst recovery costs and improve the overall economics of the process. This report documents the work completed under Task 2.0, Laboratory Support. The overall objective of Task 2.0 was to obtain and characterize the feedstocks for the contract and to provide a screening mechanism to test new catalyst systems prior to testing in the continuous pilot plant. The main elements of the experimental program for task 2.0 include: Feedstock procurement and analysis; catalyst improvements; and catalyst recycle screening.

  2. Technical and economic assessment of fluidized-bed-augmented compressed-air energy-storage system. Volume 1: Executive summary

    Science.gov (United States)

    Giramonti, A. J.; Lessard, R. D.; Merrick, D.; Hobson, M. J.

    1981-09-01

    An energy storage system for electric utility peak load applications is a modified gas turbine power system utilizing underground storage of very high pressure air. The compressed air energy storage (CAES) concept involves using off peak electricity generated from indigenous coal or nuclear sources to compress air, storing the air in large underground facilities, and withdrawing the air during peak load periods when it would be heated by combustion and expanded through gas turbines to generate power. The attractiveness of the CAES concept is based upon its potential to supply competitively priced peaking energy, to reduce peak load power plant dependence on petroleum based fuels, and to provide a means for leveling the utility system load demand. Therefore, a technical and economic assessment of coal fired fluidized bed combustor/compressed air energy storage systems was performed and is described.

  3. Measurement of the fluidized velocity in gas-solid fluidized beds based on AE signal analysis by wavelet packet transform

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An energy distribution theory was presented based on regular evolvement of energy fraction of acous-tic signals with fluidization velocity. Wavelet packet analysis was used in processing the acoustic sig-nals originated from particle impact on the wall of a fluidized bed. A new criterion of judging incipient fluidization(Umf) velocity and minimum turbulent velocity(Umt) was proposed according to the energy distribution theory. Experiments were performed with five groups of high density polyethylene(PE) particles and one bimodal PE to acquire incipient fluidization velocity and minimum turbulent velocity by using the criterion. The feasibility of this method in obtaining characteristic fluidization parameters was further verified by comparing it to results from the pressure drop method and the empirical value from industry.

  4. Measurement of the fluidized velocity in gas-solid fluidized beds based on AE signal analysis by wavelet packet transform

    Institute of Scientific and Technical Information of China (English)

    WANG JingDai; YANG YongRong; GE PengFei; SHU WeiJie; HOU LinXi

    2007-01-01

    An energy distribution theory was presented based on regular evolvement of energy fraction of acoustic signals with fluidization velocity. Wavelet packet analysis was used in processing the acoustic signals originated from particle impact on the wall of a fluidized bed. A new criterion of judging incipient fluidization (Umf) velocity and minimum turbulent velocity (Umt) was proposed according to the energy distribution theory. Experiments were performed with five groups of high density polyethylene (PE)particles and one binodal PE to acquire incipient fluidization velocity and minimum turbulent velocity by using the criterion. The feasibility of this method in obtaining characteristic fluidization parameters was further verified by comparing it to results from the pressure drop method and the empirical value from industry.

  5. FLUIDIZED BED STEAM REFORMER (FBSR) PRODUCT: MONOLITH FORMATION AND CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2006-09-13

    The most important requirement for Hanford's low activity waste (LAW) form for shallow land disposal is the chemical durability of the product. A secondary, but still essential specification, is the compressive strength of the material with regards to the strength of the material under shallow land disposal conditions, e.g. the weight of soil overburden and potential intrusion by future generations, because the term ''near-surface disposal'' indicates disposal in the uppermost portion, or approximately the top 30 meters, of the earth's surface. The THOR{reg_sign} Treatment Technologies (TTT) mineral waste form for LAW is granular in nature because it is formed by Fluidized Bed Steam Reforming (FBSR). As a granular product it has been shown to be as durable as Hanford's LAW glass during testing with ASTM C-1285-02 known as the Product Consistency Test (PCT) and with the Single Pass Flow Through Test (SPFT). Hanford Envelope A and Envelope C simulants both performed well during PCT and SPFT testing and during subsequent performance assessment modeling. This is partially due to the high aluminosilicate content of the mineral product which provides a natural aluminosilicate buffering mechanism that inhibits leaching and is known to occur in naturally occurring aluminosilicate mineral analogs. In order for the TTT Na-Al-Si (NAS) granular mineral product to meet the compressive strength requirements (ASTM C39) for a Hanford waste form, the granular product needs to be made into a monolith or disposed of in High Integrity Containers (HIC's). Additionally, the Hanford intruder scenario for disposal in the Immobilized Low Activity Waste (ILAW) trench is mitigated as there is reduced intruder exposure when a waste form is in a monolithic form. During the preliminary testing of a monolith binder for TTT's FBSR mineral product, four parameters were monitored: (1) waste loading (not optimized for each waste form tested); (2) density

  6. The dynamics of large particles in a four-compartment interconnected fluidized bed

    NARCIS (Netherlands)

    Snieders, FF; Hoffmann, AC; Cheesman, D; Yates, JG; Stein, M; Seville, JPK

    1999-01-01

    In order to investigate the potential of a four-compartment interconnected fluidized bed for the combustion of biomass, the behaviour of cylindrical pellets in a bed material of glass ballotini was characterized as a function of the operational parameters. This involved (a) studying the distribution

  7. Effect of Temperature in Fluidized Bed Fast Pyrolysis of Biomass: Oil Quality Assessment in Test Units

    NARCIS (Netherlands)

    Westerhof, R.J.M.; Brilman, D.W.F.; Swaaij, van W.P.M.; Kersten, S.R.A.

    2010-01-01

    Pine wood was pyrolyzed in a 1 kg/h fluidized bed fast pyrolysis reactor that allows a residence time of pine wood particles up to 25 min. The reactor temperature was varied between 330 and 580 °C to study the effect on product yields and oil composition. Apart from the physical−chemical analysis, a

  8. Devolatilization and ignition of coal particles in a two-dimensional fluidized bed

    NARCIS (Netherlands)

    Prins, W.; Siemons, R.; Swaaij, van W.P.M.

    1989-01-01

    In a two-dimensional (15 × 200 × 400 mm) high-temperature fluidized bed, devolatilization ignition and combustion phenomena of single coal particles have been studied. The particles, with diameters of 4–9 mm, were selected from three coal types of widely different rank: brown coal, bituminous coal,

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

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.C.

    1988-12-01

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

  10. Instability and the formation of bubbles and the plugs in fluidized beds

    Directory of Open Access Journals (Sweden)

    Piotr Schulz

    2004-01-01

    Full Text Available This is an review paper, particulary concentrate on results not many researches by reason that are explain in the text. We consider stability of disperse, two-phase flow (gas-solid particles or liquid-solid particles linear and non-linear. In particular we discuss the result of Anderson, Sundareson and Jackson (1995 [Anderson K., Sundareson S., Jackson R.: Instabilities and the formation of bubbles in fluidized beds. J. Fluid Mech. 303 (1995, 327-366] that for vertical dispersion flow one- and two-dimensional, they attack problem growing disturbances directly by numerical integration of equations of motion from given initial conditions (using computer Cray C-90. In principle, this would allow authors to explore all aspects of dynamical behaviour of fluidized beds. It is interesting mechanism of periodic plug describing by Anderson et al. and attest by other researchers. Second part of paper is more general, dedicate the problem of linear stability of uniformly fluidized state ("fluidized bed". We make the most important stages of calculations (after to Jackson (2000 [Jackson R.: The Dynamics of Fluidized Particles. Cambridge University Press 2000] and demonstrate that the majority (but not all of fluidized beds with parameters having technical importance is unstable, or stable in narrow interval of wave numbers \\(k\\.

  11. Heat transfer in a membrane assisted fluidized bed with immersed horizontal tubes

    NARCIS (Netherlands)

    Deshmukh, Salim A.R.K.; Volkers, Sander; Sint Annaland, van Martin; Kuipers, Hans

    2005-01-01

    The effect of gas permeation through horizontally immersed membrane tubes on the heat transfer characteristics in a membrane assisted fluidized bed operated in the bubbling fluidization regime was investigated experimentally. Local time-averaged heat transfer coefficients from copper tubes arranged

  12. FLUIDIZED BED STEAM REFORMING FOR TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE

    Energy Technology Data Exchange (ETDEWEB)

    HEWITT WM

    2011-04-08

    This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of fluidized bed steam reforming and its possible application to treat and immobilize Hanford low-activity waste.

  13. Numerical Simulation of Dense Gas-Solid Fluidized Beds: A Multiscale Modeling Strategy

    NARCIS (Netherlands)

    Hoef, van der M.A.; Sint Annaland, van M.; Deen, N.G.; Kuipers, J.A.M.

    2008-01-01

    Gas-solid fluidized beds are widely applied in many chemical processes involving physical and/or chemical transformations, and for this reason they are the subject of intense research in chemical engineering science. Over the years, researchers have developed a large number of numerical models of ga

  14. A novel fluidized bed respirometric technique for determination of in situ biofilm kinetics.

    Science.gov (United States)

    Chowdhury, Nabin; Nakhla, George; Zhu, Jesse

    2012-01-01

    A respirometric approach has been developed to determine heterotrophic biofilm kinetics using fluidized bioparticles--particles with attached biomass. Lava rock particles of 600 microm were used as a biomass carrier medium. The modified respirometer successfully estimates in situ biofilm kinetics of the bioparticles collected from a pilot-scale liquid-solid circulating fluidized bed (LSCFB) bioreactor. The observed maximum specific growth rates (micro(max)) of 3.69 +/- 0.44 d(-1) and biomass yields (Y(H)) of 0.36 +/- 0.03 g COD/g COD in the fluidized bed respirometers were significantly different from the micro(max) of 5.57-5.72 d(-1) and Y(H) of 0.54-0.59 g COD/g COD observed in the conventional respirometric tests for bioparticles and detached biomass. The higher Monod half-saturation coefficient (K(S)) of 186-219mg COD/L observed in the fluidized bed respirometers relative to the 49-58 mg COD/L in the conventional respirometers reveals the presence of mass transfer resistance in the LSCFB despite fluidization. Significantly reduced yields in the fluidized bed respirometers and the estimated maintenance coefficient of 1.16 d(-1) for the particulate biofilm in the LSCFB clearly emphasize that a substantial amount of substrate was utilized for cell maintenance at the low food to microorganism (S/X) ratio of 0.5 g COD/g VSS.

  15. PARTICLE FLOW, MIXING, AND CHEMICAL REACTION IN CIRCULATING FLUIDIZED BED ABSORBERS

    Science.gov (United States)

    A mixing model has been developed to simulate the particle residence time distribution (RTD) in a circulating fluidized bed absorber (CFBA). Also, a gas/solid reaction model for sulfur dioxide (SO2) removal by lime has been developed. For the reaction model that considers RTD dis...

  16. A MODEL FOR FINE PARTICLE AGGLOMERATION IN CIRCULATING FLUIDIZED BED ABSORBERS

    Science.gov (United States)

    A model for fine particle agglomeration in circulating fluidized bed absorbers (CFBAS) has been developed. It can model the influence of different factors on agglomeration, such as the geometry of CFBAs, superficial gas velocity, initial particle size distribution, and type of ag...

  17. Modeling of structural effects in biomedical elements after titanium oxidation in fluidized bed

    Directory of Open Access Journals (Sweden)

    Mendzik K.

    2010-06-01

    Full Text Available Oxidation is one of the most employed methods to improve titanium and its alloys properties especially due to medical application. This process like most of the thermochemical treatment processes substantially influences on the characteristic of surface layers and the same on its mechanical and useful properties. Oxide coatings produced during titanium oxidation were examined due to their composition identification. Titanium was oxidized in fluidized bed in temperature range between 500÷700°C. Microstructures of titanium with a visible oxide coating on its surface after thermochemical treatment and changes of grain size in core of titanium samples are described. Moreover Xray phase analysis of obtained oxides coatings was made as well as microhardness measurements of titanium surface layers after oxidation process. Finally, the surfaces of titanium after oxidation in fluidized bed were measured by Auger electron spectroscopy. All research results are used to built numerical model of oxidation process in fluidized. Titanium oxidation process in fluidized bed is very complicated, because changes of parameters are non linear characteristics. This fact and lack of mathematical algorithms describing this process makes modeling properties of titanium elements by traditional numerical methods difficult or even impossible. In this case it is possible to try using artificial neural network. Using neural networks for modeling oxidizing in fluidized bed is caused by several nets' features: non linear character, ability to generalize the results of calculations for data out of training set, no need for mathematical algorithms describing influence changes input parameters on modeling materials properties.

  18. Industrial Scale Synthesis of Carbon Nanotubes Via Fluidized Bed Chemical Vapor Deposition: A Senior Design Project

    Science.gov (United States)

    Smith, York R.; Fuchs, Alan; Meyyappan, M.

    2010-01-01

    Senior year chemical engineering students designed a process to produce 10 000 tonnes per annum of single wall carbon nanotubes (SWNT) and also conducted bench-top experiments to synthesize SWNTs via fluidized bed chemical vapor deposition techniques. This was an excellent pedagogical experience because it related to the type of real world design…

  19. Granular flow in a rotating cone partly submerged in a fluidized bed

    NARCIS (Netherlands)

    Janse, Arthur M.C.; Biesheuvel, P. Maarten; Prins, Wolter; Swaaij, van Wim P.M.

    2000-01-01

    When a rotating cone with supply openings near the bottom is partly inserted into a fluidized bed, solid particles are taken up and conveyed spirally over the inner surface. This principle for particle transport was used in a novel reactor for the flash pyrolysis of biomass with several distinct adv

  20. Continuous CO2 capture in a circulating fluidized bed using supported amine sorbents

    NARCIS (Netherlands)

    Veneman, R.; Li, Z.; Hogendoorn, J.A.; Kersten, S.R.A.; Brilman, D.W.F.

    2012-01-01

    In this work, supported amine sorbents were prepared by physical impregnation of silica and polymethylmethacrylate (PMMA) with tetraethylenepentamine (TEPA) and studied for post-combustion CO2 capture purposes in a lab scale circulating fluidized bed (CFB) reactor. Sorbent amine loading and support

  1. A small scale regularly packed circulating fluidized bed. Part I: Hydrodynamics.

    NARCIS (Netherlands)

    Ham, van der A.G.J.; Prins, W.; Swaaij, van W.P.M.

    1994-01-01

    The present investigation is based on the idea of intensifying the gas¿solids contact in a circulating fluidized bed by introducing obstacles into it. Such obstacles may effectively suppress radial inhomogeneities in the solids flux and concentration, increase the dynamic solids hold-up, and break u

  2. [Analysis of novel style biological fluidized bed A/O combined process in dyeing wastewater treatment].

    Science.gov (United States)

    Wei, Chao-Hai; Huang, Hui-Jing; Ren, Yuan; Wu, Chao-Fei; Wu, Hai-Zhen; Lu, Bin

    2011-04-01

    A novel biological fluidized bed was designed and developed to deal with high-concentration refractory organic industrial wastewater. From 12 successful projects, three cases of dyeing wastewater treatment projects with the scale of 1200, 2000 and 13000 m3/d respectively were selected to analyze the principle of treating refractory organic wastewater with fluidized bed technology and discuss the superiority of self-developed biological fluidized bed from the aspects of technical and economic feasibility. In the three cases, when the hydraulic retention time (HRT) of biological system were 23, 34 and 21. 8 h, and the volume loading of influents (COD) were 1.75, 4.75 and 2.97 kg/(m3 x d), the corresponding COD removal were 97.3%, 98.1% and 95.8%. Furthermore the operating costs of projects were 0.91, 1.17 and 0.88 yuan per ton of water respectively. The index of effluent all met the 1st grade of Guangdong Province wastewater discharge standard. Results showed that the biological fluidized bed had characteristics of shorter retention time, greater oxygen utilization rate, faster conversion rate of organic pollutants and less sludge production, which made it overcome the shortcomings of traditional methods in printing and dyeing wastewater treatment. Considering the development of technology and the combination of ecological security and recycling resources, a low-carbon wastewater treatment process was proposed.

  3. The influence of particle residence time distribution on the reactivity in fluidized bed reactors

    NARCIS (Netherlands)

    Heesink, A.B.M.; Klaus, J.; Swaaij, van W.P.M.

    1994-01-01

    The influence of particle residence time distribution on the average conversion rate (or reactivity) of particles undergoing a non-catalytic gas-solid reaction inside a continuously operated fluidized bed reactor is evaluated. A so called ß-factor is defined as the ratio of the actual reactivity in

  4. Fast Pyrolysis of Biomass in a Fluidized Bed Reactor: In Situ Filtering of the Vapors

    NARCIS (Netherlands)

    Hoekstra, Elly; Hogendoorn, Kees J.A.; Wang, Xiaoquan; Westerhof, Roel J.M.; Kersten, Sascha R.A.; Swaaij, van Wim P.M.; Groeneveld, Michiel J.

    2009-01-01

    A system to remove in situ char/ash from hot pyrolysis vapors has been developed and tested at the University of Twente. The system consists of a continuous fluidized bed reactor (0.7 kg/h) with immersed filters (wire mesh, pore size 5 μm) for extracting pyrolysis vapors. Integration of the filter s

  5. Improved Robust Adaptive Control of a Fluidized Bed Combustor for Sewage Sludge

    Institute of Scientific and Technical Information of China (English)

    MENGHong-Xia; JIAYing-Min

    2005-01-01

    This paper presents a robust model reference adaptive control scheme to deal with uncertain time delay in the dynamical model of a fluidized bed combustor for sewage sludge. The theoretical analysis and simulation results show that the proposed scheme can guarantee not only stability and robustness, but also the adaptive decoupling performance of the system.

  6. Modelling of N2O Reduction in a Circulating Fluidized Bed Boiler

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Åmand, Lars Erik; Dam-Johansen, Kim;

    1996-01-01

    The addition of limestone for sulphur retention in Fluidized Bed Combustion (FBC) has been observed to influence the emission of N2O, and in many cases a lower emission was observed. The catalytic activity of a Danish limestone (Stevns Chalk) for decomposition of N2O in a laboratory fixed bed...

  7. Electrodialytic treatment for metal removal from sewage sludge ash from fluidized bed combustion

    DEFF Research Database (Denmark)

    Pazos, Marta; Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.

    2010-01-01

    Sewage sludge contains several potentially hazardous compounds such as heavy metals, PCBs, PAHs, etc. However, elements with high agricultural value (P, K or Ca) are also present. During the last years, the fluidized bed sludge combustor (FBSC) is considered an effective and novel alternative...

  8. Laser Doppler anemometry measurements in a circulating fluidized bed of metal particles

    DEFF Research Database (Denmark)

    Ibsen, Claus Hübbe; Solberg, Tron; Hjertager, Bjørn Helge;

    2002-01-01

    Laser Doppler Anemometry (LDA) measurements were performed in a 1/9 scale model of a 12 MW circulating fluidized bed (CFB) boiler. The model was operated according to scaling laws. The 2D-LDA system used was positioned in two different ways to obtain the three velocity components u, v and w...

  9. Gas-solid hydroxyethylation of potato starch in a stirred vibrating fluidized bed reactor

    NARCIS (Netherlands)

    Kuipers, N.J M; Stamhuis, Eize; Beenackers, A.A C M

    1996-01-01

    A novel reactor for modifying cohesive C-powders such as in the gas-solid hydroxyethylation of semidry potato starch is characterized, the so-called stirred vibrating fluidized bed reactor. Good fluidization characteristics are obtained in this reactor for certain combinations of stirring and vibrat

  10. Electric-field enhanced fluidized beds : a low-energy bubble control method

    NARCIS (Netherlands)

    Kleijn van Willigen, F.

    2006-01-01

    Reducing the size of gas bubbles can significantly improve the performance of gas-solid fluidized beds one of the most common reactor types in the chemical industry applied for such diverse systems as gasoline and plastics production to foods processing. However, a control of bubbles in these reac

  11. Comparison of packed bed and fluidized bed membrane reactors for methane reforming

    NARCIS (Netherlands)

    Gallucci, Fausto; Sint Annaland, van Martin; Kuipers, J.A.M.

    2009-01-01

    In this work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, have been compared for the reforming of methane for the production of ultra-pure hydrogen. Using detailed theoretical models, the required membrane area to reach a given conversi

  12. Theoretical comparison of packed bed and fluidized bed membrane reactors for methane reforming

    NARCIS (Netherlands)

    Gallucci, Fausto; Sint Annaland, van Martin; Kuipers, J.A.M.

    2010-01-01

    In this theoretical work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, has been compared for ultra-pure hydrogen production via methane reforming. Using detailed theoretical models, the required membrane area to reach a given conversion

  13. CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101/102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; HUBER HJ

    2011-06-08

    This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-10-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannah River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FB SR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-S.2.1-20 1 0-00 1, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, 'Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies

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

    Science.gov (United States)

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

    2014-06-01

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

  15. Production of bio-oil rich in acetic acid and phenol from fast pyrolysis of palm residues using a fluidized bed reactor: Influence of activated carbons.

    Science.gov (United States)

    Jeong, Jae-Yong; Lee, Uen-Do; Chang, Won-Seok; Jeong, Soo-Hwa

    2016-11-01

    In this study, palm residues were pyrolyzed in a bench-scale (3kg/h) fast pyrolysis plant equipped with a fluidized bed reactor and bio-oil separation system for the production of bio-oil rich in acetic acid and phenol. Pyrolysis experiments were performed to investigate the effects of reaction temperature and the types and amounts of activated carbon on the bio-oil composition. The maximum bio-oil yield obtained was approximately 47wt% at a reaction temperature of 515°C. The main compounds produced from the bio-oils were acetic acid, hydroxyacetone, phenol, and phenolic compounds such as cresol, xylenol, and pyrocatechol. When coal-derived activated carbon was applied, the acetic acid and phenol yields in the bio-oils reached 21 and 19wt%, respectively. Finally, bio-oils rich in acetic acid and phenol could be produced separately by using an in situ bio-oil separation system and activated carbon as an additive.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wei-Ping Pan; Yan Cao; John Smith

    2007-03-31

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

  17. Extracting Oxygen from Lunar Simulant Using a Transparent Furnace Pulsed Fluidized Bed

    Science.gov (United States)

    Oryshchyn, L.; Paz, A.; Lee, K.; Reddington, M.

    2010-01-01

    In the event that humans return to the moon, utilizing the local materials will be beneficial for extended stays. Rather than transporting resources, such as oxygen, from Earth, NASA is investigating methods of extracting it from lunar regolith. One promising process is hydrogen reduction. In the hydrogen reduction process, lunar regolith is heated to 1000 C in the presence of hydrogen. The iron oxide (Fe-O) bonds, found in lunar material, are broken and the hydrogen attracts the oxygen to produce water vapor [Allen et al., 1996]. FeO + H2 (right arrow) Fe +H2O. The water vapor is then captured, cleaned, and electrolyzed. The hydrogen is recycled back to the reduction process and the oxygen is stored until consumed by an end user (propulsion, life support, etc.). To obtain a good oxygen yield, the majority of lunar regolith must be exposed to the hydrogen gas and have a high rate of heat transfer from heat source to particle. This is achieved with good solids mixing via fluidization or mechanical agitation. In Generation II of the ROxygen program, the ROxygen Team at Johnson Space Center (JSC) investigated the feasibility of gas only pulsed fluidization as the only means to mix synthetic lunar regolith (simulant) at high temperatures. Fluidized beds have been used in industry to effectively process powders for decades. They consist of gas flowing upward through a bed of particles. The stirring action continuously moves the grains around to achieve uniform mixing of gas, solids, and heat [Geldart, 1986]. A transparent furnace unit was developed by Thoughventions Unlimited LLC (TvU) to aid in the qualitative observation of the fluidization behavior at high temperatures. Multipoint thermocouples and pressure sensors provided quantitative information regarding the quality of mixing. The water produced was measured using humidity sensors and captured using a NASA designed and built condenser. Once the simulant was processed, pneumatically transporting the 'hot' simulant

  18. Generation and reduction of nitrogen oxides in firing different kinds of fuel in a circulating fluidized bed

    Science.gov (United States)

    Munts, V. A.; Munts, Yu. G.; Baskakov, A. P.; Proshin, A. S.

    2013-11-01

    The processes through which nitrogen oxides are generated and reduced in the course of firing different kinds of fuel in a circulating fluidized bed are addressed. All experimental studies were carried by the authors on their own laboratory installations. To construct a model simulating the generation of nitrogen oxides, the fuel combustion process in a fluidized bed was subdivided into two stages: combustion of volatiles and combustion of coke residue. The processes through which nitrogen oxides are generated and reduced under the conditions of firing fuel with shortage of oxygen (which is one of efficient methods for reducing nitrogen oxide emissions in firing fuel in a fluidized bed) are considered.

  19. Fluidized-Bed Waste-Heat Recovery System development. Semiannual report, 1 August 1981-31 January 1982

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-02-01

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

  20. Characterization of hydrodynamics and solids mixing in fluidized beds involving biomass

    Science.gov (United States)

    Fotovat, Farzam

    This thesis focuses on the characterization of hydrodynamics and mixing phenomena in fluidized beds containing mixtures of sand and irregular biomass particles. The first objective of this study is understanding the effect of the large biomass particles on the bubbling characteristics and gas distribution pattern of sand fluidized beds. The second objective is the characterization of mixing/segregation of biomass and sand particles under fluidization conditions. A variety of experimental techniques are employed to study the behavior of two constituting phases of a fluidized bed, i.e., dilute (bubble) and dense (emulsion) phases. Exploring the characteristic fluidization velocities of sand-biomass mixtures unveils that the onset of bubbling in these systems occurs at a higher gas velocity compared to that of the initial fluidization velocity (Uif). The initial bubbling velocity (Uib), the final fluidization velocity ( Uff), and the transition gas velocity from bubbling to turbulent regime (Uc) rise by increasing the fraction of biomass in the mixture. Statistical analysis of the pressure signal at top of the bed reveals that increasing the biomass load hinders the evolution of bubbles at a low gas velocity (Ubeds containing different fractions of biomass is comparable. The addition of biomass particles to a bed of sand leads to an increase in the mean voidage of the bed; however, the voidage of each phase remains unaffected. It is observed that large biomass particles trigger a break-up of the bubbles, which results in boosting bubbling frequency. The fraction of bubbles at the center of the bed increases with the load of biomass. At the wall region, however, it starts to decrease by adding 2% wt. biomass to pure sand and then increases with the further addition of biomass. The Radioactive Particle Tracking (RPT) technique is implemented in the second section of this work to study the motion and distribution of biomass particles at U=0.36 m/s and U=0.64 m/s. In this

  1. Combustion of gases released from peat or biomass in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Raiko, R. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

    1996-12-01

    Temperature and gas concentration experiments have been conducted to determine at what temperature carbon monoxide, methane and propane begin to react within the particulate phase of a bubbling fluidized bed. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 50 mm surrounded by an electric heater. Two different natural quartz sands were used (d{sub p} =0.35 mm and 0.6 mm). The bed height used varied between 100 and 260 mm (in unfluidized state). A porous plate distributor, made of kaowool, was used to avoid jets appearing at the distributor. The bed was operated at incipient fluidization (u = 5.9-9 cm/s). The bed temperatures used ranged from 600 deg C to 850 deg C. It was found that carbon monoxide, methane and propane react inside a fluidized bed, but often other conditions than temperature have a considerable effect on the rate of the reaction. The critical temperature was found to be 650 deg C for propane and carbon monoxide and 700 deg C for methane. With under-stoichiometric mixture of carbon monoxide and air the heat release can be over 2.5 MW/m{sup 3} when bed temperature is 650 deg C. According to these experiments it is obvious that the reaction mechanism for carbon monoxide oxidation inside a fluidized bed differs greatly from that of gas phase only. The results of our more than 1300 test runs show clearly the varying effects of the different bed materials. Even with the same bed material totally different results can be obtained. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies was conducted with both fresh bed particles and used bed particles. Also the effect of commonly used ingredients, like limestone and dolomite, was tested. A global model for carbon monoxide oxidation inside a fluidized bed was introduced. The model was tested against measured data from the laboratory-scale fluidized bed test rig. (Abstract Truncated)

  2. Molecular analysis of the biomass of a fluidized bed reactor treating synthetic vinasse at anaerobic and micro-aerobic conditions

    NARCIS (Netherlands)

    Rodriguez, E.; Lopes, A.; Fdz-Polanco, M.; Stams, A.J.M.; Garcia Encina, P.A.

    2012-01-01

    The microbial communities (Bacteria and Archaea) established in an anaerobic fluidized bed reactor used to treat synthetic vinasse (betaine, glucose, acetate, propionate, and butyrate) were characterized by denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis. This study was focu

  3. State of the art and the future fuel portfolio of fluidized bed combustion systems; Status und kuenftiges Brennstoffportfolio bei Wirbelschichtfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Szentannai, Pal; Friebert, Arpad; Winter, Franz [Technische Univ. Wien (Austria). Inst. fuer Verfahrens-, Umwelttechnik und technische Biowissenschaften

    2008-07-01

    Coal, biomass and substitute fuels energetically can be used efficiently and with low pollution in fluidized bed plants. In comparison to biomass there are significant differences between the circulating and stationary fluidized bed technology. The stationary fluidised bed is fed predominantly with biomasses and residual substances. Coal usually is the basis fuel in the circulating fluidised bed. Biomass and residual substances frequently are course-fired. The state of the art is the employment of a broad fuel mixture in small and large fluidized-bed combustion systems. Future developments present an increased use of sewage sludge, fluidized bed combustion systems with wood as a basis fuel, utilization of household waste and the gas production.

  4. Beckmann rearrangement of cyclohexanone oxime to {epsilon}-caprolactam using a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Dahlhoff, G.; Hoelderich, W.F. [Technische Hochschule Aachen (Germany)

    1999-07-01

    The application of a fluidized bed reactor on the heterogeneously catalyzed Beckmann rearrangement of cyclohexanone oxime to {epsilon}-caprolactam is presented. For this purpose the classic industrial synthesis route is compared to the new route catalyzed by [B]-MFI zeolite which proved to be the most suitable. To prepare the use of the catalyst the thermodynamics were calculated showing that the residence time of the reactants are of great importance. A regeneration model was developed resulting in a mathematical equation for the regeneration time calculated to seven hours under oxidative conditions. A 40 day regeneration experiment demonstrated the excellent regeneration behaviour of the chosen catalyst showing no decrease in activity after 40 recycle treatments. Finally, the experiments in a constructed non circulating fluidized bed showed good yields and selectivities (99%/91%) completely comparable to the actual synthesis route but avoiding 4 t ammonia sulphate/t product. (orig.)

  5. Combustion characteristics and emissions of Seyitomer lignite-olive cake mixture in a fluidized bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Devrim B. Kaymak; Husnu Atakul; Ekrem Ekinci [Istanbul Technical University, Istanbul (Turkey). Department of Chemical Engineering

    2007-07-01

    The low quality Turkish lignites cause acute pollution problems. Therefore, energy production from biomass, which has lower polluting potential due to its consumption of CO{sub 2} in the atmosphere and its low sulphur content, could be considered as an alternative solution. In this study, lignite-olive cake mixtures were burned in a fluidized bed combustor of 10 cm diameter. Temperature profiles, mechanisms of mixing and segregation, and gas emissions were investigated in the course of cocombustion. The lignite-olive cake mixture ratio and the coal particle size were selected as the experimental parameters. Temperature profiles of the fluidized bed show a lignite-olive cake flotsam rich behaviour and the effective parameter on segregation is the density difference between particles. The increase of the olive cake ratio in the mixture results in an important SO{sub 2} emissions decrease. The results also demonstrate that the NOx emissions remain at low values for all operating conditions.

  6. Modeling and simulation of biomass air-steam gasification in a fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By considering the features of fluidized-bed reactors and the kinetic mechanism of biomass gasification,a steady-state,isothermal,one-dimensional and twophase mathematical model of biomass gasification kinetics in bubbling fluidized beds was developed.The model assumes the existence of two phases - a bubble and an emulsion phase - with chemical reactions occurring in both phases.The axial gas dispersion in the two phases is accounted for and the pyrolysis of biomass is taken to be instantaneous.The char and gas species CO,CO2,H2,H2O,CH4 and 8 chemical reactions are included in the model.The mathematical model belongs to a typical boundary value problem of ordinary differential equations and its solution is obtained by a Matlab program.Utilizing wood powder as the feedstock,the calculated data show satisfactory agreement with experimental results and proves the effectiveness and reliability of the model.

  7. Ash and heavy metals in fluidized bed-combustion; Tuhka ja raskasmetallit puuperaeisen jaetteen kerrosleijupoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Kaessi, T.; Aittoniemi, P. [IVO International, Vantaa (Finland)

    1996-12-01

    Combustion ashes and submicron fly ash particles were characterized in two industrial boilers (bubbling vs. circulating fluidized bed) burning paper mill deinking sludge and bark or wood as support fuel. Bulk samples from fly ash, circulating ash and bottom ash were analyzed. Fine particles in fly ash were monitored and sampled for microscopic studies. The mass size distribution of fly ash was measured and the chemical composition according to particle size was analyzed. The results showed that ash consists of large and friable clusters formed by sintering of small mineral particles originating from paper fillers. Very few ash particles were fused and they were found only among the smallest particles. No agglomerates of fused particles were found. If the residence time in furnace is long enough sintering may proceed further and ash structure grows more dense. No indication of ash vaporization was detected. These results were similar for bubbling and circulating fluidized bed boilers. (author)

  8. Conformal nanocoating of zirconia nanoparticles by atomic layer deposition in a fluidized bed reactor.

    Science.gov (United States)

    Hakim, Luis F; George, Steven M; Weimer, Alan W

    2005-07-01

    Primary zirconia nanoparticles were conformally coated with alumina ultrathin films using atomic layer deposition (ALD) in a fluidized bed reactor. Alternating doses of trimethylaluminium and water vapour were performed to deposit Al(2)O(3) nanolayers on the surface of 26 nm zirconia nanoparticles. Transmission Fourier transform infrared spectroscopy was performed ex situ. Bulk Al(2)O(3) vibrational modes were observed for coated particles after 50 and 70 cycles. Coated nanoparticles were also examined with transmission electron microscopy, high-resolution field emission scanning electron microscopy and energy dispersive spectroscopy. Analysis revealed highly conformal and uniform alumina nanofilms throughout the surface of zirconia nanoparticles. The particle size distribution and surface area of the nanoparticles are not affected by the coating process. Primary nanoparticles are coated individually despite their high aggregation tendency during fluidization. The dynamic aggregation behaviour of zirconia nanoparticles in the fluidized bed plays a key role in the individual coating of nanoparticles.

  9. Solids mixing in bubbling fluidized beds: CFD-based analysis of Bubble Dynamics and Time Scales

    Science.gov (United States)

    Bakshi, Akhilesh; Altantzis, Christos; Ghoniem, Ahmed

    2016-11-01

    In bubbling fluidized bed reactors, solids mixing is critical because it directly affects fuel segregation and residence time. However, there continues to be a lack of understanding because (a) most diagnostic techniques are only feasible in lab-scale setups and (b) the dynamics are sensitive to the operating conditions. Thus, quantitative estimates of mixing (e.g., dispersion coefficient, mixing indices) often span orders of magnitude although it is well accepted that the micro-mixing and gross circulation of solid particles is driven by bubble motion. To quantify this dependence, solids mixing is investigated using fine-grid 3D CFD simulations of a large 50 cm diameter fluidized bed. Detailed diagnostics of the computed flow-field data are performed using MS3DATA, a tool that we developed to detect and track bubbles, and the solids motion is correlated with the spatial and size distribution of bubbles. This study will be useful for quantifying mixing at commercial scales.

  10. Flow Field of Circulating Fluidized Bed Reactor with Venturi Inlet Configuration

    Institute of Scientific and Technical Information of China (English)

    HU Jinbang; LI Yanping; CHEN Anxin

    2005-01-01

    Different two-equation k-ε models were used to simulate the gas flow field generated by a new type of circulating fluidized bed reactor with venturi gas distributor. The numerical results were compared with the experimental data. It has been shown that the simulation results from the standard k-ε model have the best match with the experimental data. Based on this model, the gas flow field in the venturi diffuser and riser was analyzed by the concept of velocity nonuniformity and dead zone percentage. Both the nonuniformity of gas velocity and the dead zone percentage reach the maximum at the venturi outlet due to the effect of the vortex. At the same time, it provides a good platform for the further optimization of the inlet configuration of circulating fluidized bed reactor.

  11. Bio-oil production from palm fronds by fast pyrolysis process in fluidized bed reactor

    Science.gov (United States)

    Rinaldi, Nino; Simanungkalit, Sabar P.; Kiky Corneliasari, S.

    2017-01-01

    Fast pyrolysis process of palm fronds has been conducted in the fluidized bed reactor to yield bio-oil product (pyrolysis oil). The process employed sea sand as the heat transfer medium. The objective of this study is to design of the fluidized bed rector, to conduct fast pyrolysis process to product bio-oil from palm fronds, and to characterize the feed and bio-oil product. The fast pyrolysis process was conducted continuously with the feeding rate around 500 g/hr. It was found that the biomass conversion is about 35.5% to yield bio-oil, however this conversion is still minor. It is suggested due to the heating system inside the reactor was not enough to decompose the palm fronds as a feedstock. Moreover, the acids compounds ware mostly observed on the bio-oil product.

  12. Preliminary market assessment of fluidized-bed waste-heat recovery technology

    Energy Technology Data Exchange (ETDEWEB)

    Campos, F.T.; Fey, C.L.; Grogan, P.J.; Klein, N.P.

    1980-06-01

    A preliminary assessment of fluidized-bed waste-heat recovery (FBWHR) system market potential is presented with emphasis on the factors influencing industrial acceptability. Preliminary market potential areas are identified based on the availability of waste heat. Trends in energy use are examined to see the effect they might have on these market potential areas in the future. Focus groups interviews are used to explore important factors in the industrial decision-making process. These important factors are explored quantitatively in a survey of industrial plant engineers. The survey deals with the waste-heat boiler configuration of the FBWHR system. Results indicate market acceptance of the fluidized-bed waste-heat boiler could be quite low.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wei-Ping Pan; Yan Cao; Songgeng Li

    2006-04-01

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2006 through March 31, 2006. Work was performed on the following activities. First, the fabrication and manufacture of the CFBC Facility were completed. The riser, primary cyclone and secondary cyclone of Circulating Fluidized Bed (CFB) Combustor have been erected. Second, the Mercury Control Workshop and the Grand Opening of Institute for Combustion Science and Environmental Technology (ICSET) were successfully held on February 22 and 23, 2006, respectively. Third, effects of hydrogen chlorine (HCl) and sulfur dioxide (SO{sub 2}) on mercury oxidation were studied in a drop tube reactor. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

  14. Anti-shock loading capability of a fluidized-bed flocculator

    Institute of Scientific and Technical Information of China (English)

    Dandan Zhou; Shuangshi Dong; Yang Yang; Wenyuan Zhao; Linlin Gao

    2012-01-01

    The efficiency of a fluidized-bed flocculator with 800-μm particles of 1360 kg/m3 in density was studied,and the anti-shock capability of the unit was estimated for three kinds of industrial wastewater:heavy turbidity wastewater,dispersed dyeing wastewater and starch wastewater.Steady removal efficiency was contributed by the following characteristics of the flocculator:(1) the dynamic conditions,flocculation time and velocity gradient,which were stabilized at a steady level as the loading rate changed; (2) hydrodynamic characteristics,especially the considerable rise of expanded bed height with increasing superficial velocity when small and light particles were employed as the solid phase; (3) flocs growth characteristics in the fluidized bed,which caused the density and size of the flocs being maintained at a compensational relationship,resulted the stabilized settling velocity of the flocs.

  15. Treatment of TFT-LCD wastewater containing ethanolamine by fluidized-bed Fenton technology.

    Science.gov (United States)

    Anotai, Jin; Chen, Chia-Min; Bellotindos, Luzvisminda M; Lu, Ming-Chun

    2012-06-01

    The objectives of this study are: (1) to determine the effect of pH, initial concentration of Fe(2+) and H(2)O(2) dosage on the removal efficiency of MEA by fluidized-bed Fenton process and Fenton process, (2) to determine the optimal conditions for the degradation of ethanolamine from TFT-LCD wastewater by fluidized-bed Fenton process. In the design of experiment, the Box-Behnken design was used to optimize the operating conditions. A removal efficiency of 98.9% for 5mM MEA was achieved after 2h under optimal conditions of pH3, [Fe(2+)]=5mM and [H(2)O(2)]=60mM.

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

    Science.gov (United States)

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

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

  17. Effect of promoters on dynamics of gas-solid fluidized bed-Statistical and ANN approaches

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this study, a bubbling fluidized bed column, 99 mm in inside diameter and 960 mm in height, was used to investigate the effect of rod and disc promoters on fluctuation and expansion ratios. Factorial design (statistical approach) and artificial neural network (ANN) models were developed to predict the fluctuation and expansion ratios in this gas-solid fluidized bed with varying gas flow rates, bed heights, particle sizes and densities. The fluctuation and expansion predicted using these statistical and ANN models, for beds with and without promoters, were found to agree well with corresponding experiments. The statistical model was found to be superior to the ANN model due to its ability to take into account both individual and interactive effects. The rod promoters were found to be more effective in reducing bed fluctuation, and in increasing bed expansion at high gas mass velocities.

  18. Standard Guide for Dosimetry In Radiation Processing of Fluidized Beds and Fluid Streams

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This guide describes several dosimetry systems and methods suitable for the documentation of the irradiation of product transported as fluid or in a fluidized bed. 1.2 The sources of penetrating ionizing radiation included in this guide are electron beams, X-rays (bremsstrahlung) and gamma rays. 1.3 Absorbed doses from 10 to 100,000 gray are considered, including applications such as disinfestation, disinfection, bioburden reduction, sterilization, crosslinking and graft modification of products, particularly powders and aggregates. 1.4 This guide does not purport to address the safety concerns, if any, associated with the use of fluidized beds and streams incorporating sources of ionizing radiation. It is the responsibility of the user of this guide to establish appropriate safety and health practices and to determine compliance with regulatory limitations prior to use.

  19. Comprehensive Mathematical Model for Coal Combustion in a Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    金晓钟; 吕俊复; 杨海瑞; 刘青; 岳光溪; 冯俊凯

    2001-01-01

    Char combustion is on a special reducing condition in the dense bed of a circulating fluidized bedcombustor. Experimental findings were used to develop a comprehensive mathematical model to simulate thehydrodynamic and combustion processes in a circulating fluidized bed combustor. In the model, gas-solidinteraction was used to account for the mass transfer between the bubble phase and the emulsion phase in thedense bed, which contributes to the reducing atmosphere in the dense bed. A core-annular structure wasassumed in the dilute area rather than a one-dimensional model. The submodels were combined to build thecomprehensive model to analyze the combustion in a circulating fluidized bed combustor and the effect ofoperating parameters on the coal combustion. The model predictions agree well with experimental results.

  20. Using of fluidized-bed jet mill to a super fine comminution of steel composite

    Directory of Open Access Journals (Sweden)

    D. Urbaniak

    2015-01-01

    Full Text Available In many industries the demand for very fine material increases. In the metallurgical industry, for example, there is increasing use of the production of high density metal elements with the use of metallurgical powder composites. The use of powder composites requires prior their grinding. Unfortunately, the very fine grinding is not an easy process. The using for this purpose fluidized-bed jet mill was proposed in the paper. The attempts of grinding of metallurgical powder were carried out in the fluidized-bed jet mill. After the experiment analyses of particle size distribution of grinding products were performed. The results are presented in graphs. Analyses of the obtained results concluded that the grinding of very fine metallurgical composite is possible and produces positive results.

  1. Effect of Microwave on Fluidized Bed Drying of Beetroot (Beta vulgaris L.

    Directory of Open Access Journals (Sweden)

    Yashwant Kumar

    2016-07-01

    Full Text Available In the present work, an attempt has been made to study the effect of inlet air temperature and velocity on the drying characteristics of beetroot’s (Beta vulgaris L. pieces in microwave assisted fluidized bed drying (MAFBD system. The results were compared with samples of beetroot dried in a fluidized bed dryer (FBD at the same combination of temperatures and air velocities. The selected inlet air temperatures and inlet air velocities were 60°C, 67.50°C and 75°C and 9 m/s, 10.50 m/s and 12 m/s, respectively. Moisture content and outlet air humidity was measured at 5 minutes interval. The MAFBD method offered two to three times reduction in drying time as compared to the FBD method. It was also observed that the beetroot samples obtained from the MAFBD system had lower final moisture content than those obtained from the FBD system.

  2. Heat Transfer between Horizontal Finned Tubes and a Gas-Solid Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Grewal, N.S.; Cheung, T.K.; Saxena, S.C.

    1985-04-01

    The heat-transfer coefficients are measured between electrically heated V-thread tubes and square fluidized beds of alumina and silica sand. The effect of particle size, mass fluidizing velocity, V-thread pitch, and tube pitch on the heat transfer rate is investigated. One-dimensional and two-dimensional heat conduction models are developed for determining the temperature distribution in a V-thread fin. The models are used to calculate the corrected heat-transfer coefficients for the finned tubes. A correlation for the fin effectiveness factor is proposed and is found to be reliable to predict its value for finned tubes with geometry and orientation similar to that in the present investigation. The correlation in conjunction with the existing correlatins for the heat-transfer coefficient for smooth tubes is found, in general, to predict the coefficients for finned tubes immersed in a fluidized bed within + or - 25%.

  3. Effects of fluidized bed combustion residue on pecan seedling growth and nutrient content. [Carya illinoensis

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, J.H.; White, A.W. Jr.; Bennett, O.L.

    1985-01-01

    Fluidized bed combustion residue from a calcitic limestone source (FBCRC), a by-product of scrubbing SO/sub 2/ from fossil fuel fired boilers using the FBC technique was evaluated as a source of calcium for pecan (Carya illinoensis (Wang.) K. Koch) seedlings. Fluidized bed combustion residue produced following injection of calcitic limestone into the combustion chamber was more effective in neutralizing soil acidity and increasing extractable soil Ca levels than agricultural calcitic limestone. The Ca concentration in the pecan leaves was increased linearly by Ca rates for both 12- and 24-week growth periods, but stem and petiole Ca concentration was increased linearly for the second 12-week growth period. Macronutrient concentrations were affected by Ca rates for both 12- and 24-week growth periods, but no effect was observed with Ca source. The primary difference was between the control and all other Ca rates.

  4. DISCRETE PARTICLE SIMULATION OF SIZE SEGREGATION OF PARTICLE MIXTURES IN A GAS FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Y. Q. Feng; A. B. Yu

    2006-01-01

    This paper presents a study of the mixing/segregation behaviour of particle mixtures in a gas fluidized bed by use of the discrete particle simulation. Spherical particles with diameters 2 mm (jetsam) and 1 mm (flotsam) and density 2 500 kg·m-3 are used as solid mixtures with different volume fractions. The particles are initially packed uniformly in a rectangular bed and then fluidized by gas uniformly injected at the bottom of the bed. The gas injection velocities vary to cover fixed, partially and fully fluidized bed conditions. Segregation/mixing behaviour is discussed in terms of flow patterns, solid concentration profile and mixing kinetics. The results show that segregation, as a transient fluidization process, is strongly affected by gas injection velocities for a given particle mixture. With the increase of the volume fraction of flotsam, size segregation appears at lower velocities.

  5. Carbon attrition during the circulating fluidized bed combustion of a waste-derived fuel

    Energy Technology Data Exchange (ETDEWEB)

    Arena, U. [Consiglio Nazionale delle Ricerche, Naples (Italy). Inst. for Combustion Research; Naples Univ. (Italy). Dept. of Environmental Sciences; Mastellone, M.L. [Naples Univ. Federico II (Italy). Dept. of Chemical Engineering

    1999-07-01

    A biomass obtained as residue from food manufacturing of pine nuts was batchwise fed in a laboratory scale circulating fluidized bed combustor. The apparatus was operated under both inert and oxidizing conditions in order to establish the relative importance of purely mechanical attrition and combustion-assisted attrition in generating carbon fines. For each run, carbon load and carbon particle size distribution in the riser and rates of attrited carbon fines escaping from the combustor were determined as a function of time. A parallel investigation was carried out with a bubbling fluidized bed combustor in order to point out peculiarities of attrition in the two apparatus. Results were compared with those obtained by burning in the same combustor a bituminous coal and a packaging-derived fuel, obtained from monomaterial collections of polyethylene terephtalate bottles. A different attrition phenomenology was found for each fuel and its peculiar features were taken into account. (orig.)

  6. Tube array heat transfer in fluidized beds; a study of particle size effects

    Energy Technology Data Exchange (ETDEWEB)

    Chung, T.Y.; Welty, J.R. (Oregon State Univ., Corvallis, OR (USA). Dept. of Mechanical Engineering)

    1989-07-01

    Experiments were performed with an array of horizontal tubes, arranged in a regular equilateral triangular pattern, immersed in a fluidized bed operating at 812 {Kappa}. Data are reported for heat transfer between the bed and a centrally-located tube in the array. Both total and radiative heat transfer rates were measured for superficial velocities spanning the range from packed bed conditions to over twice the minimum fluidization velocity. Results are presented for five different-size particles. Local heat transfer values, measured around the tube periphery, and integrated averages are reported for all test conditions. Comparisons are also made between the heat transfer behavior of a tube in an array and that for a single tube in a hot fluidized bed under the same overall operating conditions. The results of this comparison suggests that the two mechanisms, gas convection and radiation, are competing effects.

  7. Multi-scale Analysis of Chaotic Characteristics in a Gas-Solid Fluidized Bed%气固流化床中非线性特性的多尺度分析

    Institute of Scientific and Technical Information of China (English)

    甄玲; 王晓萍; 陈伯川; 黄海; 黄春艳

    2002-01-01

    Deterministic chaos theory offers useful quantitative tools to characterize the non-linear dynamic behavior of a fluidized bed and the developed complexity theory presents a new approach to evaluate finite sequences.In this paper, the non-linear, hydrodynamic behavior of the pressure fluctuation signals in a reactor was discussed by chaos parameters and complexity measures. Coherent results were achieved by our multi-scale analysis, which further exposed the behavior in a gas-solid two-phase system.

  8. Fluidized-bed reactor model with generalized particle balances. Part 2. Coal combustion application

    Energy Technology Data Exchange (ETDEWEB)

    Overturf, B.W.; Reklaitis, G.V.

    1983-09-01

    In the second part, the model is applied to the study of an atmospheric fluidized-bed coal combustor. Case studies are investigated to show the effects of a number of parameters. Proper representation of the grid region and use of actual feed distributions are shown to be essential to the prediction of combustor performance. Better particle elutriation and single-particle combustion sub-models are found to be key requirements for improved combustor modelling.

  9. Fluidized bed drying characteristics and modeling of ginger ( zingiber officinale) slices

    Science.gov (United States)

    Parlak, Nezaket

    2015-08-01

    In this study fluidized bed drying characteristics of ginger have been investigated. The effects of the fluidizing air temperature, velocity, humidity and bed height on the drying performance of ginger slices have been found. The experimental moisture loss data of ginger slices has been fitted to the eight thin layer drying models. Two-term model drying model has shown a better fit to the experimental data with R2 of 0.998 as compared to others.

  10. Proceedings of the Sixth International Conference on Fluidized Bed Combustion. Volume 1. Plenary sessions

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-08-01

    The Sixth International Conference on Fluidized Bed Combustion was held at the Atlanta Hilton, Atlanta, Georgia, April 9-11, 1980. The papers in this volume involved presentation of the research and development programs of the US (US DOE, TVA, EPRI and US EPA), United Kingdom, Federal Republic of Germany and the People's Republic of China. Eight papers from Vol. 1 (Plenary Sessions) of the proceedings have been entered individually into EDB and ERA. (LTN)

  11. Direct iron ore reduction by methane in a fluidized bed. Final report, November 1989-December 1992

    Energy Technology Data Exchange (ETDEWEB)

    van der Vaart, D.R.; Conger, W.L.

    1993-08-01

    Novel process chemistry of methane in a fluidized bed was investigated to identify a more direct route to producing the reducing gas needed in the Direct Reduction of iron ore. A rather surprising result, however, of the study was the discovery of an inexpensive and attrition-resistant catalytic material for methane oxidative coupling. The iron oxide impregnated, non-porous silica oxide was found to be relatively active, and quite selective when steam was added to the methane/air feed.

  12. A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems.

    Science.gov (United States)

    Lu, Juan; Zhang, Xiaoqian; Li, Jianzhou; Yu, Liang; Chen, Ermei; Zhu, Danhua; Zhang, Yimin; Li, LanJuan

    2016-01-01

    A fluidized bed bioreactor containing encapsulated hepatocytes may be a valuable alternative to a hollow fiber bioreactor for achieving the improved mass transfer and scale-up potential necessary for clinical use. However, a conventional fluidized bed bioreactor (FBB) operating under high perfusion velocity is incapable of providing the desired performance due to the resulting damage to cell-containing microcapsules and large void volume. In this study, we developed a novel diversion-type microcapsule-suspension fluidized bed bioreactor (DMFBB). The void volume in the bioreactor and stability of alginate/chitosan microcapsules were investigated under different flow rates. Cell viability, synthesis and metabolism functions, and expression of metabolizing enzymes at transcriptional levels in an encapsulated hepatocyte line (C3A cells) were determined. The void volume was significantly less in the novel bioreactor than in the conventional FBB. In addition, the microcapsules were less damaged in the DMFBB during the fluidization process as reflected by the results for microcapsule retention rates, swelling, and breakage. Encapsulated C3A cells exhibited greater viability and CYP1A2 and CYP3A4 activity in the DMFBB than in the FBB, although the increases in albumin and urea synthesis were less prominent. The transcription levels of several CYP450-related genes and an albumin-related gene were dramatically greater in cells in the DMFBB than in those in the FBB. Taken together, our results suggest that the DMFBB is a promising alternative for the design of a bioartificial liver system based on a fluidized bed bioreactor with encapsulated hepatocytes for treating patients with acute hepatic failure or other severe liver diseases.

  13. Preliminary study of a radiantly heated fluidized bed for the production of high purity silicon

    Science.gov (United States)

    Levenspiel, O.; Larson, M.; Zhang, G. T.; Ouyang, F.

    1983-01-01

    The preparation of very pure silicon from silane (SIH4) using radiant heating of the hot silicon particles of a fluidized bed is discussed. The fraction of electrical energy supplied to the heater which is actually absorbed by the particles and the heat transfer coefficient between the hot bed and the cool distributor plate were investigated. The experimental design is presented and the results of the study are summarized.

  14. Cleaning and Heat Transfer in Heat Exchanger with Circulating Fluidized Beds

    Science.gov (United States)

    Kang, Ho Keun; Ahn, Soo Whan; Choi, Jong Woong; Lee, Byung Chang

    2010-06-01

    Fluidized bed type heat exchangers are known to increase the heat transfer and prevent the fouling. For proper design of circulating fluidized bed heat exchanger it is important to know the effect of design and operating parameters on the bed to the wall heat transfer coefficient. The present experimental and numerical study was conducted to investigate the effects of circulating solid particles on the characteristics of fluid flow, heat transfer and cleaning effect in the fluidized bed vertical shell and tube type heat exchanger with counterflow, at which a variety of solid particles such as glass (3 mmF), aluminum (2˜3 mmF), steel (2˜2.5 mmF), copper (2.5 mmF) and sand (2˜4 mmF) were used in the fluidized bed with a smooth tube. Seven different solid particles have the same volume, and the effects of various parameters such as water flow rates, particle diameter, materials and geometry were investigated. The present experimental and numerical results showed that the flow velocity range for collision of particles to the tube wall was higher with heavier density solid particles, and the increase in heat transfer was in the order of sand, copper, steel, aluminum, and glass. This behaviour might be attributed to the parameters such as surface roughness or particle heat capacity. Fouling examination using 25,500 ppm of ferric oxide (Fe2O3) revealed that the tube inside wall is cleaned by a mild and continuous scouring action of fluidized solid particles. The fluidized solid particles not only keep the surface clean, but they also break up the boundary layer improving the heat transfer coefficient even at low fluid velocities.

  15. The Study of Gas-Dynamic Processes in the Current Boiler Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Baturin Dmitry A.

    2015-01-01

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

  16. The Study of Dynamic Processes in the Boiler Furnace with Circulating Fluidized Bed

    OpenAIRE

    Gil A. V.; Baturin D. A.

    2016-01-01

    The paper presents a numerical simulation of the furnace with a circulating fluidized bed. Numerical study carried out on all volume of the combustion chamber. The results contours of particulate matter concentration and of velocities, as well as a graphical representation of changes in the concentration of particles on the bed height are shown. Simulation performed in Eulerian - Eulerian and Lagrange representation on a 3D model.

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

    Science.gov (United States)

    Gil, Andrey V.; Gil, Alexandra Y.

    2015-01-01

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

  18. MULTIFRACTAL ANALYSIS OF PARTICLE-FLUID SYSTEM IN A CIRCULATING FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Liping; Ma; Weixing; Huang; Yanfu; Shi; Huarui; Yu; Jingxu; Zhu

    2005-01-01

    In this paper, multifractal analysis together with wavelet transform modulus maxima (WTMM) method is used to analyze the fluctuating signals of circulating fluidized bed (CFB). Singularity spectrum shows that the gas-particle flow in CFB has multifractal character. Motion behavior of the particle-fluid system of CFB can be described by singularity spectrum. Intermittency index can be used to determine the transition of flow regime from fast fluidization to pneumatic conveying.

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

    Directory of Open Access Journals (Sweden)

    Gil Andrey V.

    2015-01-01

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

  20. Fluidization behavior in a circulating slugging fluidized bed reactor. Part II: Plug characteristics

    NARCIS (Netherlands)

    Putten, van I.C.; Sint Annaland, van M.; Weickert, G.

    2007-01-01

    In the transporting square nosed slugging fluidization regime (0.4 < u0 < 1.0m/s) a bed of polyethylene powder with a low density (ρ = 900/kg/m3) and a large particle size distribution (70 < dρ < 1600µm) was operated in two circulating fluidized bed systems (riser diameters 0.044 and 0.105 m). A rel