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Sample records for bubbling fluidized bed

  1. Bubble size reduction in a fluidized bed by electric fields

    NARCIS (Netherlands)

    Kleijn van Willigen, F.; Van Turnhout, J.; Van Ommen, J.R.; Van den Bleek, C.

    2003-01-01

    The reduction of the size of bubbles can improve both selectivity and conversion in gas-solid fluidized beds. Results are reported of the reduction of bubble size by the application of electric fields to uncharged, polarizable particles in fluidized beds. It is shown how average bubble diameters can

  2. Eulerian simulations of bubble behaviour in a two-dimensional gas-solid bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Lu Huilin; Liu Wentie; Zhao Guangbo; He Yurong [Harbin Institute of Technology (China). Dept. of Power Engineering; Li Feng [Jiangxi Boiler Co. Ltd., Nanchang (China)

    2002-07-01

    In the present study, the CFD model is based on a two-fluid model extended with the kinetic theory of granular flow. The simulation results of bubble diameter and bubble rise velocity are compared to the Darton equation and the Davidson model in a free bubbling fluidized bed. The predicted values are in reasonable agreement with the values from the Darton bubble size equation and the Davidson model for isolated bubbles. It is shown that the break-up and direct wall interaction effects influence the dynamic bubble behavior in the free bubbling fluidized beds. (author)

  3. 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

  4. CFD-DEM study of effect of bed thickness for bubbling fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Tingwen, Li; Gopalakrishnan, Pradeep; Garg, Rahul; Shahnam, Mehrdad

    2011-10-01

    The effect of bed thickness in rectangular fluidized beds is investigated through the CFD–DEM simulations of small-scale systems. Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing, bed expansion, bubble behavior, solids velocities, and particle kinetic energy. Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters. However, a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters, indicating the transition from 2D flow to 3D flow within the range of 20–40 particle diameters. Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds. Hence, for quantitative comparison with experiments in pseudo-2D columns, the effect of walls has to be accounted for in numerical simulations.

  5. A Bubble-Based Drag Model at the Local-Grid Level for Eulerian Simulation of Bubbling Fluidized Beds

    Directory of Open Access Journals (Sweden)

    Kun Hong

    2016-01-01

    Full Text Available A bubble-based drag model at the local-grid level is proposed to simulate gas-solid flows in bubbling fluidized beds of Geldart A particles. In this model, five balance equations are derived from the mass and the momentum conservation. This set of equations along with necessary correlations for bubble diameter and voidage of emulsion phase is solved to obtain seven local structural parameters (uge, upe, εe, δb, ub, db, and ab which describe heterogeneous flows of bubbling fluidized beds. The modified drag coefficient obtained from the above-mentioned structural parameters is then incorporated into the two-fluid model to simulate the hydrodynamics of Geldart A particles in a lab-scale bubbling fluidized bed. The comparison between experimental and simulation results for the axial and radial solids concentration profiles is promising.

  6. 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

  7. Metal wastage design guidelines for bubbling fluidized-bed combustors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lyczkowski, R.W.; Podolski, W.F.; Bouillard, J.X.; Folga, S.M. [Argonne National Lab., IL (United States)

    1992-11-01

    These metal wastage design guidelines identify relationships between metal wastage and (1) design parameters (such as tube size, tube spacing and pitch, tube bundle and fluidized-bed height to distributor, and heat exchanger tube material properties) and (2) operating parameters (such as fluidizing velocity, particle size, particle hardness, and angularity). The guidelines are of both a quantitative and qualitative nature. Simplified mechanistic models are described, which account for the essential hydrodynamics and metal wastage processes occurring in bubbling fluidized beds. The empirical correlational approach complements the use of these models in the development of these design guidelines. Data used for model and guideline validation are summarized and referenced. Sample calculations and recommended design procedures are included. The influences of dependent variables on metal wastage, such as solids velocity, bubble size, and in-bed pressure fluctuations, are discussed.

  8. High temperature degradation by erosion-corrosion in bubbling fluidized bed combustors

    Directory of Open Access Journals (Sweden)

    Hou Peggy

    2004-01-01

    Full Text Available Heat-exchanger tubes in fluidized bed combustors (FBCs often suffer material loss due to combined corrosion and erosion. Most severe damage is believed to be caused by the impact of dense packets of bed material on the lower parts of the tubes. In order to understand this phenomenon, a unique laboratory test rig at Berkeley was designed to simulate the particle hammering interactions between in-bed particles and tubes in bubbling fluidized bed combustors. In this design, a rod shaped specimen is actuated a short distance within a partially fluidized bed. The downward specimen motion is controlled to produce similar frequencies, velocities and impact forces as those experienced by the impacting particle aggregates in practical systems. Room temperature studies have shown that the degradation mechanism is a three-body abrasion process. This paper describes the characteristics of this test rig, reviews results at elevated temperatures and compares them to field experience. At higher temperatures, deposits of the bed material on tube surfaces can act as a protective layer. The deposition depended strongly on the type of bed material, the degree of tube surface oxidation and the tube and bed temperatures. With HCl present in the bed, wastage was increased due to enhanced oxidation and reduced oxide scale adherence.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ceccio, Steven [Univ. of Michigan, Ann Arbor, MI (United States); Curtis, Jennifer [Univ. of Florida, Gainesville, FL (United States)

    2011-04-15

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

  10. Experimental study on solids mixing and bubble behavior in a pseudo-2D, freely bubbling, gas-solid fluidized bed using PIV and DIA

    NARCIS (Netherlands)

    Laverman, J.A.; Roghair, Ivo; van Sint Annaland, M.; Kuipers, J.A.M.

    2007-01-01

    The hydrodynamics of a freely bubbling, gas-solid fluidized bed has been investigated experimentally with non-invasive measuring techniques in a pseudo-2D column filled with glass beads of 400-600 μm fluidized with air. Particle Image Velocimetry (PIV) combined with Digital Image Analysis (DIA) has

  11. DOLOMITE DESULFURIZATION BEHAVIOR IN A BUBBLING FLUIDIZED BED PILOT PLANT FOR HIGH ASH COAL

    Directory of Open Access Journals (Sweden)

    G. M. F. Gomes

    Full Text Available Abstract Although fluidized bed in situ desulphurization from coal combustion has been widely studied, there are aspects that remain under investigation. Additionally, few publications address Brazilian coal desulphurization via fluidized beds. This study used a 250 kWth bubbling fluidized bed pilot plant to analyze different aspects of the dolomite desulphurization of two Brazilian coals. Superficial velocities of 0.38 and 0.46 m/s, flue gas recycling, Ca/S molar ratios and elutriation were assessed. Results confirmed the influence of the Ca/S molar ratio and superficial velocity - SO2 conversion up to 60.5% was achieved for one coal type, and 70.9% was achieved for the other type. A recycling ratio of 54.6% could increase SO2 conversion up to 86.1%. Elutriation and collection of ashes and Ca-containing products did not present the same behavior because a lower wt. % of CaO was collected by the gas controlled mechanism compared to the ash.

  12. CFD study of the minimum bubbling velocity of Geldart A particles in gas-fluidized beds

    NARCIS (Netherlands)

    Wang, J.; van der Hoef, Martin Anton; Kuipers, J.A.M.

    2010-01-01

    The minimum bubbling velocity, which demarcates the homogeneous and heterogeneous fluidization regimes, plays a pivotal role in gas fluidization of Geldart A particles. We systematically study the effect of gas and particle properties on the minimum bubbling velocity of Geldart A particles in

  13. Modeling of reaction kinetics in bubbling fluidized bed biomass gasification reactor

    Energy Technology Data Exchange (ETDEWEB)

    Thapa, R.K.; Halvorsen, B.M. [Telemark University College, Kjolnes ring 56, P.O. Box 203, 3901 Porsgrunn (Norway); Pfeifer, C. [University of Natural Resources and Life Sciences, Vienna (Austria)

    2013-07-01

    Bubbling fluidized beds are widely used as biomass gasification reactors as at the biomass gasification plant in Gussing, Austria. The reactor in the plant is a dual circulating bubbling fluidized bed gasification reactor. The plant produces 2MW electricity and 4.5MW heat from the gasification of biomass. Wood chips as biomass and olivine particles as hot bed materials are fluidized with high temperature steam in the reactor. As a result, biomass undergoes endothermic chemical reaction to produce a mixture of combustible gases in addition to some carbon-dioxide (CO2). The combustible gases are mainly hydrogen (H2), carbon monoxide (CO) and methane (CH4). The gas is used to produce electricity and heat via utilization in a gas engine. Alternatively, the gas is further processed for gaseous or liquid fuels, but still on the process of development level. Composition and quality of the gas determine the efficiency of the reactor. A computational model has been developed for the study of reaction kinetics in the gasification rector. The simulation is performed using commercial software Barracuda virtual reactor, VR15. Eulerian-Lagrangian approach in coupling of gas-solid flow has been implemented. Fluid phase is treated with an Eulerian formulation. Discrete phase is treated with a Lagrangian formulation. Particle-particle and particle-wall interactions and inter-phase heat and mass transfer have been taken into account. Series of simulations have been performed to study model prediction of the gas composition. The composition is compared with data from the gasifier at the CHP plant in Güssing, Austria. The model prediction of the composition of gases has good agreements with the result of the operating plant.

  14. Numerical Modelling of a Fast Pyrolysis Process in a Bubbling Fluidized Bed Reactor

    Science.gov (United States)

    Jalalifar, S.; Ghiji, M.; Abbassi, R.; Garaniya, V.; Hawboldt, K.

    2017-07-01

    In this study, the Eulerian-Granular approach is applied to simulate a fast pyrolysis bubbling fluidized bed reactor. Fast pyrolysis converts biomass to bio-products through thermochemical conversion in absence of oxygen. The aim of this study is to employ a numerical framework for simulation of the fast pyrolysis process and extend this to more complex reactor geometries. The framework first needs to be validated and this was accomplished by modelling a lab-scale pyrolysis fluidized bed reactor in 2-D and comparing with published data. A multi-phase CFD model has been employed to obtain clearer insights into the physical phenomena associated with flow dynamics and heat transfer, and by extension the impact on reaction rates. Biomass thermally decomposes to solid, condensable and non-condensable and therefore a multi-fluid model is used. A simplified reaction model is sued where the many components are grouped into a solid reacting phase, condensable/non-condensable phase, and non-reacting solid phase (the heat carrier). The biomass decomposition is simplified to four reaction mechanisms based on the thermal decomposition of cellulose. A time-splitting method is used for coupling of multi-fluid model and reaction rates. A good agreement is witnessed in the products yield between the CFD simulation and the experiment.

  15. Study of a 30 MW bubbling fluidized bed combustor based on co ...

    Indian Academy of Sciences (India)

    determined distinctly. Singh et al (2013). 1. This paper summarized the CFD modeling tool to. 1. Due to variation in size of biomass particles the Eulerian– study combustion and gasification of fuels in fluidized. Eulerian approach with biomass considering bed devices combustion/gasification issues in dense fluidized beds is ...

  16. A system for measuring bubble voidage and frequency around tubes immersed in a fluidized bed of particles.

    Science.gov (United States)

    Whitty, Kevin J; Siddoway, Michael

    2010-07-01

    Gas-solid fluidized beds are common in chemical processing and energy production industries. These types of reactors frequently have banks of tubes immersed within the bed to provide heating or cooling, and it is important that the fluid dynamics within these bundles is efficient and uniform. This paper presents a simple, low-cost method for quantitatively analyzing the behavior of gas bubbles within banks of tubes in a fluidized bed cold flow model. Two probes, one containing an infrared emitter and one containing an infrared (IR) detector, are placed into adjacent glass tubes such that the emitter and detector face each other. As bubbles pass through the IR beam, the detector signal increases due to less solid material blocking the path between the emitter and detector. By calibrating the signal response to known voidage of the material, one can measure the bubble voidage at various locations within the tube bundle. The rate and size of bubbles passing through the beam can also be determined by high frequency data collection and subsequent analysis. This technique allows one to develop a map of bubble voidage within a fluidized bed, which can be useful for model validation and system optimization.

  17. Combustion performance evaluation of Posidonia oceanica using TGA and bubbling fluidized-bed combustor (batch reactor

    Directory of Open Access Journals (Sweden)

    Agnieszka Plis

    2016-01-01

    Full Text Available Combustion performance of emerging raw marine biomass called Posidonia oceanica (PO was investigated using TGA apparatus and a bubbling fluidized-bed batch reactor. The kinetic mechanism and parameters of the combustion process were determined. The Flynn-Wall-Ozawa (FWO method and data fitting method were analyzed. It was observed that a model based on consecutive processes: devolatilisation and char combustion for two fractions of PO (holocellulose and lignin, is the best model for the analyzed cases. Combustion performance was observed using a BFB reactor and the composition of flue gas after combustion was analyzed, and the conversion of NOx and SO2 was taken into account. The relatively low SO2 emission in the case of PO combustion can be attributed to the impact of the sulphur self-retention (SSR process. The results were compared to the combustion of wood biomass and Turow lignite. The results showed the good combustion performance of PO.

  18. Gasification of torrefied Miscanthus × giganteus in an air-blown bubbling fluidized bed gasifier.

    Science.gov (United States)

    Xue, G; Kwapinska, M; Horvat, A; Kwapinski, W; Rabou, L P L M; Dooley, S; Czajka, K M; Leahy, J J

    2014-05-01

    Torrefaction is suggested to be an effective method to improve the fuel properties of biomass and gasification of torrefied biomass should provide a higher quality product gas than that from unprocessed biomass. In this study, both raw and torrefied Miscanthus × giganteus (M×G) were gasified in an air-blown bubbling fluidized bed (BFB) gasifier using olivine as the bed material. The effects of equivalence ratio (ER) (0.18-0.32) and bed temperature (660-850°C) on the gasification performance were investigated. The results obtained suggest the optimum gasification conditions for the torrefied M × G are ER 0.21 and 800°C. The product gas from these process conditions had a higher heating value (HHV) of 6.70 MJ/m(3), gas yield 2m(3)/kg biomass (H2 8.6%, CO 16.4% and CH4 4.4%) and cold gas efficiency 62.7%. The comparison between raw and torrefied M × G indicates that the torrefied M × G is more suitable BFB gasification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. A One-Dimensional (1-D) Three-Region Model for a Bubbling Fluidized-Bed Adsorber

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Andrew; Miller, David C.

    2012-01-01

    A general one-dimensional (1-D), three-region model for a bubbling fluidized-bed adsorber with internal heat exchangers has been developed. The model can predict the hydrodynamics of the bed and provides axial profiles for all temperatures, concentrations, and velocities. The model is computationally fast and flexible and allows for any system of adsorption and desorption reactions to be modeled, making the model applicable to any adsorption process. The model has been implemented in both gPROMS and Aspen Custom Modeler, and the behavior of the model has been verified.

  20. Study on the shape and flow characteristics of the formed bubbles in a pressurized fluidized bed. For the case of formed bubble from single nozzle; Kaatsu ryudosonai seisei kiho no keijo to sono ryudo ni kansuru kenkyu. Tan'itsu nozzle kara hasseisuru kiho no baa

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Y.; Miyamoto, M.; Guo, Z. [Yamaguchi University, Yamaguchi (Japan); Kishimoto, Y. [Mitsubishi Kakoki Kaisha, Ltd., Tokyo (Japan)

    2000-12-25

    It is most important factors that were dealt with the size and production frequency of formed bubble and the rising state of bubble in the distributor vicinity at a solid-gas fluidized bed for the mixing and reacting process of the fluidized bed. Especially it is more complicated in the case of the pressurized fluidized bed. In order to understand the mechanism and behavior of the formed bubble, the investigations on the shape and flow characteristics of the formed bubble in a pressurized bed was carried out and bubbles were formed at a single nozzle in the pressurized solid-gas fluidized bed with distributor. Experimental data were obtained from visualized image of the bubble using the shadow-graph method and were analyzed. Those results indicate that the size and rising velocity of bubble were increased with relation to increase of the nozzle flow rate and these bubble behavior were varied with increase of the pressure in bed. (author)

  1. Fluidized bed coal desulfurization

    Science.gov (United States)

    Ravindram, M.

    1983-01-01

    Laboratory scale experiments were conducted on two high volatile bituminous coals in a bench scale batch fluidized bed reactor. Chemical pretreatment and posttreatment of coals were tried as a means of enhancing desulfurization. Sequential chlorination and dechlorination cum hydrodesulfurization under modest conditions relative to the water slurry process were found to result in substantial sulfur reductions of about 80%. Sulfur forms as well as proximate and ultimate analyses of the processed coals are included. These studies indicate that a fluidized bed reactor process has considerable potential for being developed into a simple and economic process for coal desulfurization.

  2. Atmospheric and pressurized fluidized bed technology

    Energy Technology Data Exchange (ETDEWEB)

    Anthony, E.J.B. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

    2003-07-01

    Fluidization states, bubbling and circulating fluidized beds, and the basics of pressurized fluidized bed combustion are outlined. PFBC demonstration plants, cogeneration, operational units and possible new plants, growth of PFBC capacity, sulphur capture, sulphation, phase composition of ashes, and actual performance in reduction of sulphur dioxide and nitrogen oxides are described. Problems occurring during operation show that turbines need to be protected and that hot gas filters degrade and are unreliable. It is concluded that the future of PFBC depends on Asian development and that the technology may be stimulated by stricter pollution controls. 5 figs., 4 tabs.

  3. Study of a 30 MW bubbling fluidized bed combustor based on co ...

    Indian Academy of Sciences (India)

    During experimental investigations, the study of bed temperatures and steam temperatures at different zones has been done for coal fired and biomass fired combustors with 30% share. No clear effects of co-firing on boiler performance are observed. However, the operational behavior of the boiler in terms of bed ...

  4. Scaling of pressurized fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Guralnik, S.; Glicksman, L.R.

    1994-10-01

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

  5. Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus.

    Science.gov (United States)

    Skoglund, Nils; Grimm, Alejandro; Ohman, Marcus; Boström, Dan

    2014-02-20

    This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K 2 CO 3 ) and alkaline-earth metal (CaCO 3 ) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%-95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca 9 (K,Mg,Fe)(PO 4 ) 7 , for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO 2 ) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi 2 O 6 ) was formed. Most of the alkaline-earth metals

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

    Science.gov (United States)

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

    1968-01-01

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

  7. Fluidized bed gasification of selected South African coals

    CSIR Research Space (South Africa)

    Engelbrecht, AD

    2010-05-01

    Full Text Available An investigation was undertaken to ascertain the suitability of four selected low grade, South African coals for gasification in a bubbling fluidized bed for production of synthesis gas and for the development of integrated gasification combined...

  8. 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

    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...

  9. Simultaneous measurement of local particle movement, solids concentrations and bubble properties in fluidized bed reactors using a novel fiber optical technique

    Energy Technology Data Exchange (ETDEWEB)

    Tayebi, Davoud

    1998-12-31

    This thesis develops a new method for simultaneous measurements of local flow properties in highly concentrated multiphase flow systems such as gas-solid fluidized bed reactors. The method is based on fiber optical technique and tracer particles. A particle present in the measuring volume in front of the probe is marked with a fluorescent dye. A light source illuminates the particles and the detecting fibres receive reflected light from uncoated particles and fluorescent light from the tracer particle. Using optical filters, the fluorescent light can be distinguished and together with a small fraction of background light from uncoated particles can be used for determination of local flow properties. Using this method, one can simultaneously measure the local movement of a single tracer particle, local bubble properties and the local solids volume fractions in different positions in the bed. The method is independent of the physical properties of the tracer particles. It is also independent of the local solids concentrations in the range of 0 to 60 vol.-%, but is mainly designed for highly concentrated flow systems. A computer programme that uses good signals from at least three sensors simultaneously to calculate the tracer particle velocity in two dimensions have been developed. It also calculates the bubble properties and local solids volume fractions from the same time series. 251 refs., 150 figs., 5 tabs.

  10. Dynamic Modeling and Control Studies of a Two-Stage Bubbling Fluidized Bed Adsorber-Reactor for Solid-Sorbent CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Modekurti, Srinivasarao; Bhattacharyya, Debangsu; Zitney, Stephen E.

    2013-07-31

    A one-dimensional, non-isothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid-sorbent carbon dioxide (CO{sub 2}) capture using Aspen Custom Modeler® (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributor have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO{sub 2} capture rate and flue gas outlet temperatures have been studied by simulating typical disturbances such as change in the temperature, flowrate, and composition of the incoming flue gas from pulverized coal-fired power plants. In control studies, the performance of a proportional-integral-derivative (PID) controller, feedback-augmented feedforward controller, and linear model predictive controller (LMPC) are evaluated for maintaining the overall CO{sub 2} capture rate at a desired level in the face of typical disturbances.

  11. Staged cascade fluidized bed combustor

    Science.gov (United States)

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

    1984-01-01

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

  12. Allothermal steam gasification of biomass in cyclic multi-compartment bubbling fluidized-bed gasifier/combustor - new reactor concept.

    Science.gov (United States)

    Iliuta, Ion; Leclerc, Arnaud; Larachi, Faïçal

    2010-05-01

    A new reactor concept of allothermal cyclic multi-compartment fluidized bed steam biomass gasification is proposed and analyzed numerically. The concept combines space and time delocalization to approach an ideal allothermal gasifier. Thermochemical conversion of biomass in periodic time and space sequences of steam biomass gasification and char/biomass combustion is simulated in which the exothermic combustion compartments provide heat into an array of interspersed endothermic steam gasification compartments. This should enhance unit heat integration and thermal efficiency and procure N(2)-free biosyngas with recourse neither to oxygen addition in steam gasification nor contact between flue and syngas. The dynamic, one-dimensional, multi-component, non-isothermal model developed for this concept accounts for detailed solid and gas flow dynamics whereupon gasification/combustion reaction kinetics, thermal effects and freeboard-zone reactions were tied. Simulations suggest that allothermal operation could be achieved with switch periods in the range of a minute supporting practical feasibility for portable small-scale gasification units. Copyright 2009 Elsevier Ltd. All rights reserved.

  13. Char binder for fluidized beds

    Science.gov (United States)

    Borio, Richard W.; Accortt, Joseph I.

    1981-01-01

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

  14. Fluidized bed desulfurization

    Science.gov (United States)

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

    1985-01-01

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

  15. 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 detail. S...

  16. 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.

  17. Kinetics of gasification and combustion of residues, biomass and coal in a bubbling fluidized bed; Die Kinetik der Vergasung und Verbrennung unterschiedlicher Abfaelle, Biomassen und Kohlen in der blasenbildenden Wirbelschicht

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, S.; Krumm, W. [Siegen Univ. (Gesamthochschule) (Germany). Lehrstuhl fuer Energie- und Umweltverfahrenstechnik

    1998-09-01

    The combustion and gasification characteristics of Rhenish brown coal, domestic waste, waste plastics, wood and sewage sludge were investigated in a bubbling atmospheric fluidized bed in the laboratory scale. The materials were pyrolyzed in the fluidized bed in a nitrogen atmosphere. The residual coke was combuted in the presence of oxygen with varying operating parameters or else gasified in the presence of carbon dioxide. The different materials were characterized by global combustion rates, and kinetic parameters were determined for residual coke combustion. (orig.) [Deutsch] Das Verbrennungs- und Vergasungsverhalten von Rheinischer Braunkohle, Hausmuell, Restkunststoff, Holz und Klaerschlamm wurde in einer blasenbildenden, atmosphaerischen Laborwirbelschicht untersucht. Die Einsatzstoffe wurden in der mit Stickstoff fluidisierten Wirbelschicht pyrolysiert. Der verbleibende Restkoks wurde anschliessend unter Variation der Betriebsparameter mit Sauerstoff verbrannt oder mit Kohlendioxid vergast. Die unterschiedlichen Einsatzstoffe wurden durch globale Vebrennungsraten charakterisiert. Fuer die Restkoksverbrennung wurden kinetische Parameter ermittelt. (orig.)

  18. 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.

  19. 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.

  20. Modeling of fuel mixing in fluidized bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    David Pallares; Filip Johnsson [Chalmers University of Technology, Goeteborg (Sweden). Department of Energy and Environment

    2008-12-15

    This paper presents a three-dimensional model for fuel mixing in fluidized bed combustors. The model accounts for mixing patterns which were experimentally shown to govern mixing in risers with geometry and operational conditions representative for furnaces in fluidized bed combustors. The mixing process is modeled for three different solid phases in the furnace and the model, which includes the return leg, can be applied both under bubbling and circulating regimes. The semi-empirical basis of the model was previously validated in different large-scale fluidized bed combustors and is combined with a model for fuel particle conversion to obtain the fuel concentration field. Model results are compared with experimental data from the Chalmers 12 MW{sub th} CFB combustor, yielding a reasonable agreement.

  1. Particle pressures in fluidized beds. Second year annual report

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-31

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

  2. 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.

  3. A novel technique for particle tracking in cold 2-dimensional fluidized beds - simulating fuel dispersion

    Energy Technology Data Exchange (ETDEWEB)

    David Pallares; Filip Johnsson [Chalmers University of Technology, Goeteborg (Sweden). Department of Energy and Environment, Energy Conversion

    2006-04-15

    This paper presents a novel technique for particle tracking in 2-dimensional fluidized beds operated under ambient conditions. The method is applied to study the mixing mechanisms of fuel particles in fluidized beds and is based on tracking a phosphorescent tracer particle by means of video recording with subsequent digital image analysis. From this, concentration, velocity and dispersion fields of the tracer particle can be obtained with high accuracy. Although the method is restricted to 2-dimensional, it can be applied under flow conditions qualitatively resembling a fluidized-bed combustor. Thus, the experiments cover ranges of bed heights, gas velocities and fuel-to-bed material density and size ratios typical for fluidized-bed combustors. Also, several fluidization regimes (bubbling, turbulent, circulating and pneumatic) are included in the runs. A pattern found in all runs is that the mixing pattern of the tracer (fuel) solids is structured in horizontally aligned vortexes induced by the bubble flow. The main bubble paths always give a low concentration of tracer solids and with the tracer moving upwards, while the downflow of tracer particles in the dense bottom bed is found to take place in zones with low bubble density and at the sidewalls. The amount of bed material (bed height) has a strong influence on the bottom bed dynamics (development and coalescence of bubbles) and, consequently, on the solids mixing process. Local dispersion coefficients reach maximum values around the locations of bubble eruptions, while, in the presence of a dense bottom bed, an increase in fluidization velocity or amount of bed material enhances dispersion. Dispersion is found to be larger in the vertical than in the horizontal direction, confirming the critical character of lateral fuel dispersion in fluidized-bed combustors of large cross section.

  4. 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.

  5. Recent advances in fluidized bed drying

    Science.gov (United States)

    Haron, N. S.; Zakaria, J. H.; Mohideen Batcha, M. F.

    2017-09-01

    Fluidized bed drying are very well known to yield high heat and mass transfer and hence adopted to many industrial drying processes particularly agricultural products. In this paper, recent advances in fluidized bed drying were reviewed and focus is given to the drying related to the usage of Computational Fluid Dynamics (CFD). It can be seen that usage of modern computational tools such as CFD helps to optimize the fluidized bed dryer design and operation for lower energy consumption and thus better thermal efficiency. Among agricultural products that were reviewed in this paper were oil palm frond, wheat grains, olive pomace, coconut, pepper corn and millet.

  6. A CFD-DEM study of single bubble formation in gas fluidization of spherical and non-spherical particles

    Directory of Open Access Journals (Sweden)

    Shrestha Siddhartha

    2017-01-01

    Full Text Available Bubble dynamics significantly affect the hydrodynamics of gas-solid fluidized bed since they influence the gas-solid mixing. In this study, simulations using CFD-DEM were carried out to characterize the bubble size and shape for a bubble formed at a single orifice in gas-solid fluidized bed. Impact of parameters such as jet velocity, orifice size and particle shape on bubble equivalent diameter and bubble aspect ratio were analysed and discussed. Bubble equivalent diameter was found to increase with increasing jet velocity, decreasing bed width to orifice width ratio, and particle shape deviating from spherical. The bubble shape illustrated by aspect ratio, was found to elongate more as it rise through the bed and then commence to expand horizontally after it was detached from the orifice. Aspect ratio was found to be closer to a circle for the bubble at higher jet velocity, lower orifice width to bed ratio and for non-spherical particles.

  7. A CFD-DEM study of single bubble formation in gas fluidization of spherical and non-spherical particles

    Science.gov (United States)

    Shrestha, Siddhartha; Zhou, Zongyan

    2017-06-01

    Bubble dynamics significantly affect the hydrodynamics of gas-solid fluidized bed since they influence the gas-solid mixing. In this study, simulations using CFD-DEM were carried out to characterize the bubble size and shape for a bubble formed at a single orifice in gas-solid fluidized bed. Impact of parameters such as jet velocity, orifice size and particle shape on bubble equivalent diameter and bubble aspect ratio were analysed and discussed. Bubble equivalent diameter was found to increase with increasing jet velocity, decreasing bed width to orifice width ratio, and particle shape deviating from spherical. The bubble shape illustrated by aspect ratio, was found to elongate more as it rise through the bed and then commence to expand horizontally after it was detached from the orifice. Aspect ratio was found to be closer to a circle for the bubble at higher jet velocity, lower orifice width to bed ratio and for non-spherical particles.

  8. Experimental Investigation of Radial Gas Dispersion Coefficients in a Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Jiří Štefanica

    2012-01-01

    Full Text Available In a fluidized bed boiler, the combustion efficiency, the NOX formation rate, flue gas desulphurization and fluidized bed heat transfer are all ruled by the gas distribution. In this investigation, the tracer gas method is used for evaluating the radial gas dispersion coefficient. CO2 is used as a tracer gas, and the experiment is carried out in a bubbling fluidized bed cold model. Ceramic balls are used as the bed material. The effect of gas velocity, radial position and bed height is investigated.

  9. Sustainable generation of bioenergy in fluidized bed boilers

    Energy Technology Data Exchange (ETDEWEB)

    Offenbacher, Elmar

    2010-07-01

    Full text: These days, reflecting a growing demand of heat and power, increasing cost for fossil fuels and more environmental issues (limitation of greenhouse gases, regulations for landfill etc.), the sustainable conversion of renewable fuels to bioenergy is becoming increasingly important. Renewable fuels cover a wide range, from traditional wood, bark, harvesting residues to all kind of sludges, and contain a remarkable calorific value that can easily compete with fossil fuels such as brown coal and lignite. The combustion of these renewable fuels does not create any greenhouse gases. The favourable technology for combusting renewable fuels is the fluidized bed technology, bubbling fluidized bed and circulating fluidized bed, as this system provides maximum fuel flexibility combined with high combustion efficiency and low emissions. Neither a variation of the water content and the heating value nor different sources of the material streams have a negative impact on the combustion. Fluidized bed boilers can switch from one fuel to the other quiet easily and can also be fired with conventional fuels that ensure a smooth and reliable generation of process heat and/or power in any case. The reasons that make fluidized bed boilers the most sustainable combustion technology for renewable fuels are various: The main feature of this technology is the principle of staged combustion of the fuel: The oxygen level in the fluidized bed is limited and hence only a part of the fuel is combusted, whereas the rest of the fuel is gasified. The staged combustion concept results in a homogenous temperature profile of less than 850 deg. C in the furnace and low NO{sub x} emission as a consequence. The turbulences in the furnace result and an efficient combustion that is combined with very low CO and TOC emissions in the flue gas. This paper will describe design features of the latest fluidized bed technology especially suitable for firing renewable fuels, and the research results of

  10. Gas filtration in binary fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Rincon, J. (Univ. de Castilla-La Mancha, Ciudad Real (Spain)); Guardiola, J.; Romero, A. (Univ. de Alcala de Henares, Madrid (Spain))

    1992-12-01

    A systematic experimental study of aerosol filtration in a binary fluidized bed of dielectric material is carried out. Measurements of the collection efficiency when such parameters as gas velocity, bed height, collecting mixture, and column diameter are varied over a wide range have been made. Experimental evidence is given to show that charges generated naturally by triboelectrification of the bed dielectric particles can considerably increase the efficiency of such beds. Furthermore, it is demonstrated that a proper choice of the fluidized mixture can significantly improve the performance of such filters.

  11. Capacitor model to interpret the electric behavior of fluidized beds. Influence of apparatus geometry

    Energy Technology Data Exchange (ETDEWEB)

    Rojo, V.; Guardiola, J.; Vian, A.

    1986-01-01

    This work provides a model to know the degree of electrification in fluidized beds on the basis of voltage measurements between an electric probe and a metallic distributor. The model is based on the similarity of behavior between the probe-bed-distributor system and a capacitor. The influence of three variables related to apparatus geometry - height of probe, column diameter and height of bed - has been studied in an air fluidized bed of glass beads. The results show that the degree of bed electrification is not influenced by the column diameter; the effect of bed height depends on the quality of fluidization: with a bubbling bed the degree of electrification increases with bed height whereas the opposite effect is observed with a slugging bed. Additional fixed bed experiments make clear that the rate of charge dissipation grows for increasing values of bed height and column diameter, and for decreasing values of probe height.

  12. Hydrodynamic studies of the flow of fine particles through a fluidized dense bed of coarse solids

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, J.

    1993-12-31

    This study explains the hydrodynamics of a circulating fluidized bed (CFB) system, the Battelle Multi-Solids Fluidized Bed System (MSFB). It consists of a circulating fluidized bed of fine particles superimposed on a bubbling bed of coarse solids. One way to characterize such a system is to describe the mechanism of gas-solid flow through the bed. The gas flow in systems like these is through bubbles or slugs (regions of voids containing little or no solids). Bubbles are typically characterized by their size (length or diameter), their rise velocity, and their frequency. Another task of the initial phase of this study is to characterize an L-valve, a solids-recirculating device commonly used in an MSFB. Next, the mechanism of fine particle movement through a bubbling region of coarse fluidized solids is studied in considerable detail. Bubble characteristics are studied in a variety of systems of coarse particles with fines passing through at high velocity. Amongst numerous optical, electrical and other techniques available for the study of the passage of bubbles, the pressure fluctuation technique is the most robust. In this investigation, pressure probes are connected to pressure transducers which are in turn linked to an on-line data acquisition system supported on a microcomputer. A commercially available software package (Notebook) is used to sample pressure at specified points in the fluidized bed at extremely fast rates, of up to 200 Hz. This resulted in pressure-time traces which are analysed to give bubble length, bubble rise velocity, and bubble frequency. Another important objective of this study is to estimate the fine particle residence time in the dense bed section. A defluidization technique is utilized in experimentally measuring the solids holdup in the dense bed. A mathematical model is developed from first principles, based on a momentum balance on the fine particles.

  13. Spatiotemporal dynamics of a shallow fluidized bed.

    Energy Technology Data Exchange (ETDEWEB)

    Aranson, I. S.; Tsimring, L. S.; Clark, D. K.

    2000-12-05

    An experimental and theoretical study of the dynamics of an air-fluidized thin granular layer is presented. Near the threshold of instability, the system exhibits critical behavior with remarkably long transient dynamics. Above the threshold of fluidization the system undergoes a Hopf bifurcation as the layer starts to oscillate at a certain frequency due to a feedback between the layer dilation and the airflow rate. Based on our experimental data, we formulate a the simple dynamical model which describes the transition in a shallow fluidized bed.

  14. 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.

  15. Analysis of circulating fluidized bed combustion technology

    Energy Technology Data Exchange (ETDEWEB)

    Furusawa, Takehiko; Shimizu, Tadaaki; Yang, Guilin

    1987-05-20

    Fluidized bed combustors are commercialized as a technology to combust solid fuels with higher efficiency and lower emission and have functions of both combustion and simultaneous desulfurization and NOx reduction with dense phase fluidized beds but it is not so easy to realize these problems. The technology of circulating fluidized bed coal combustion is expected to offer potential break-through of various problems. But the details are not reported so far. Quantitative analysis of present situations was conducted and future problems were shown with officially available informations. This analysis includes the circulating rate and loading of solids, heat recovery and heat transfer rate as a function of loading of solids, the design of cyclones related to high solid concentration within the combustor, sulfur retention with reduced Ca/S ratio and problems related to NOx reduction to be developed in future. (51 refs, 23 figs, 8 tabs)

  16. Fluidized bed selective pyrolysis of coal

    Science.gov (United States)

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

    1992-12-15

    The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyses the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step. 9 figs.

  17. 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.

  18. The characterization of fluidization behavior using a novel multichamber microscale fluid bed

    DEFF Research Database (Denmark)

    Räsänen, Eetu; Rantanen, Jukka; Mannermaa, Jukka-Pekka

    2004-01-01

    of fluidization behavior in variable conditions. The results were evaluated on the basis of two common computational methods, the minimum fluidization velocity, and the Geldart classification. The materials studied were different particle sizes of glass beads, microcrystalline cellulose, and silicified...... microcrystalline cellulose. During processing, the different characteristic fluidization phases (e.g., plugging, bubbling, slugging, and turbulent fluidization) of the materials were observed by the pressure difference over the bed. When the moisture content of the process air was increased, the amount of free...

  19. Fluidized-bed combustion reduces atmospheric pollutants

    Science.gov (United States)

    Jonke, A. A.

    1972-01-01

    Method of reducing sulfur and nitrogen oxides released during combustion of fossil fuels is described. Fuel is burned in fluidized bed of solids with simultaneous feeding of crushed or pulverized limestone to control emission. Process also offers high heat transfer rates and efficient contacting for gas-solid reactions.

  20. Multiscale modeling of gas-fluidized beds

    NARCIS (Netherlands)

    van der Hoef, Martin Anton; van Sint Annaland, M.; Ye, 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

  1. 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

  2. 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...

  3. 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

  4. Fluidized-Bed Cleaning of Silicon Particles

    Science.gov (United States)

    Rohatgi, Naresh K.; Hsu, George C.

    1987-01-01

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

  5. Low-grade coal and biomass co-combustion on fluidized bed: exergy analysis

    Energy Technology Data Exchange (ETDEWEB)

    Martin, C.; Villamanan, M.A.; Chamorro, C.R.; Segovia, J.J. [University of Valladolid (Spain). Dept. of Energy; Otero, J.; Cabanillas, A. [Environment and Technology Ciemat, Madrid (Spain). Dept. of Fossil Fuels

    2006-03-01

    The purpose of this work is to prove the technical feasibility of the bubbling fluidized bed co-combustion, using biomass and low-grade coal mixtures and applying the exergy method. The pilot plant modelled is an atmospheric bubbling fluidized bed combustion chamber with a nominal capacity of 1 MWth. We have applied the mass balance, the energy balance and the exergy balance to the plant in nine experiments, which have been performed at different operation conditions. The exergy analysis includes the calculation of the exergy destruction and the exergetic efficiency of the plant for these experiments. An estimation of the irreversibility cost is also evaluated. (author)

  6. Fluidized bed adsorption of cephalosporin C.

    Science.gov (United States)

    Hicketier, M; Buchholz, K

    2002-02-28

    Fluidized bed adsorption can substantially simplify the recovery of products from fermentation. There are, however, several critical parameters, which have a significant influence on the performance of such systems. This paper presents experimental results on the adsorption of an antibiotic, Cephalosporin C, on macroporous adsorbents of the polystyrene type and on an ion exchanger. Internals (static mixers) were used to control bed expansion and mixing, the range of flow rates could thus be extended significantly. An integrated mathematical model was developed comprising bed expansion, residence time distribution and mixing, adsorption kinetics and equilibria.

  7. Electrostatic collection efficiency in binary fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Romero, A.; Guardiola, J.; Rincon, J. (Univ. of Alcala de Henares, Madrid (Spain))

    1992-01-01

    Fluidized beds of binary mixtures have been used to clean air streams containing dust particles in the size range 4.4 to 14 {mu}m. All beds were composed of glass beads and plastic granules mixed at different proportions. The effect on the electrostatic collection efficiency of a number of variables, including type of collecting mixture, bed height, and gas velocity, was examined. To calculate the single collection efficiency from experimental results, an early model proposed by Clift et al. was used. The electrostatic collection efficiency was determined by subtracting the other individual mechanism efficiencies from the single particle collection efficiency.

  8. 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.

  9. 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)

  10. 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

  11. 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

  12. 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.

  13. Paste drying control in a rotating-distributor fluidized bed

    OpenAIRE

    Gómez Hernández, Jesús.

    2016-01-01

    Fluidized beds are used for a wide variety of processes due to its high rates of heat and mass transfer. Due to that, fluidized beds are used for a variety of applications ranging from the gasification or combustion of biomass, to coating and drying processes. All these industrial applications show the main influence of the zone close to the distributor on the bed dynamics. In this way, a non-homogeneous mixing in this zone between dense and gas phases leads to fluidization ...

  14. Interpretation of CT-Scan Sinograms to Study the Dynamic Flow Properties of a Fluidized Bed

    Science.gov (United States)

    Bennett, M. A.; Kryuchkov, S.; Kantzas, A.

    2007-06-01

    Fast moving objects typically produce poor quality images and motion-artifacts in Computed Tomography (CT) scans. The imaging of bubbling gas-solid fluidized beds, where many bubbles may pass through the sensing cross-section in a tomographic measurement, gives such a problem. Previously, one method of dealing with this problem was to remove artifacts from the reconstructed image itself through low pass filtering. However, this method leads to lost information from the images. When the concentration of bubbles is low, and their shape is close to cylindrically symmetric, analysis of consecutive scans in the raw data sinogram can also provide valuable information about the frequency of bubbles passing, and about their individual size, shape and position. Then, utilizing the inverse Abel transform, this information can then also be used to contribute to time averaged properties of the bed's behaviour such as voidage distribution, bubble phase area fraction and spatial bubble number distribution.

  15. Pyrolysis reactor and fluidized bed combustion chamber

    Science.gov (United States)

    Green, Norman W.

    1981-01-06

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

  16. 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.

  17. Hydrocarbonization of coal in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, E.L.; Cochran, H.D. Jr.; Westmoreland, P.R.; Brown, C.H. Jr.; Oswald, G.E.; Miller, C.L.

    1979-01-01

    Hydrocarbonization is a relatively simple method of producing oil, substitute natural gas, and devolatilized char from coal. Oil and gas yields have been determined for hydrocarbonization of coal in a 0.10-m-diam fluidized-bed reactor operated at 2170 kPa and at temperatures ranging from 694 to 850 K. Subbituminous coal and bituminous coal that was pretreated with CaO, NaOH, and Na/sub 2/CO/sub 3/ to eliminate agglomeration was used. Oil yields up to 21% (based on moisture- and ash-free coal) were achieved. Data on the composition of the oil, gas, and char products are presented.

  18. Scale-up guidelines for a circulating fluidized bed biomass pyrolyzer

    Energy Technology Data Exchange (ETDEWEB)

    Haslinger, W.; Hofbauer, H. [Technische Univ., Vienna (Austria); Gavriil, L.; Boukis, I. [Center for Renewable Energy Sources (Greece)

    1999-07-01

    A new circulating fluidized bed design has been proposed and successfully operated at lab scale (10 kg/h biomass feed). This fluidized bed system consists of a bubbling bottom bed, above this bottom bed a riser, a cyclone and a return leg. The heat necessary for the pyrolysis process is produced in the bottom bed by burning some solid residue from the pyrolysis that circulates together with the bed material as the bottom bed is fluidized with air. The flue gas from the bottom bed enters into the riser and serves there as transport gas. The circulation rate is very sensitive to the amount of bed inventory and the fluidization velocities. As the riser uses the flue gas of the dense bottom bed the ratio of the cross sections of the two fluidized beds has to be in a certain range to get a satisfying operation. The fluid mechanic behavior of this new circulating fluidized bed pyrolyzer has been studied using three different cold flow models. One cold flow model was built for the existing 10 kg/h lab scale pyrolyzer according to Glicksman's (1984) similarity rules. The purpose of this cold model was to study the fluid mechanics and optimize the performance with respect to the pyrolysis process. For scale-up purposes further cold flow models (135 kg/h, 1000 kg/h) have been designed, built and investigated intensively. The idea and the new design of the pyrolyzer, the results of the experimental work as well as the scale-up criteria will be presented. (orig.)

  19. Artificial Neural Network Modeling of an Inverse Fluidized Bed ...

    African Journals Online (AJOL)

    The application of neural networks to model a laboratory scale inverse fluidized bed reactor has been studied. A Radial Basis Function neural network has been successfully employed for the modeling of the inverse fluidized bed reactor. In the proposed model, the trained neural network represents the kinetics of biological ...

  20. Artificial Neural Network Modeling of an Inverse Fluidized Bed ...

    African Journals Online (AJOL)

    MICHAEL

    modeling of the inverse fluidized bed reactor. In the proposed model, the trained neural network represents the kinetics of biological decomposition of pollutants in the reactor. The neural network has been trained with experimental data obtained from an inverse fluidized bed reactor treating the starch industry wastewater.

  1. The mechanism of char ignition in fluidized bed combustors

    NARCIS (Netherlands)

    Siemons, R.V.

    1987-01-01

    Knowledge about ignition processes of coal in fluidized beds is of importance for the start-up and dynamic control of these combustors. Initial experiments in a transparent fluidized bed scale model showed the existence of a considerable induction period for the ignition of char, especially at low

  2. Single particle behaviour in circulating fluidized bed combustors

    DEFF Research Database (Denmark)

    Erik Weinell, Claus

    1994-01-01

    An investigation of single particle behaviour in a circulating fluidized bed combustor is described, relating to sulphur capture reactions by limestone under alternate oxidizing and reducing conditions present in a circulating fluidized bed combustor, and to the devolatilization and burn out...

  3. Controlling thermal properties of dense gas fluidized beds for concentrated solar power by internal and external solids circulation

    Science.gov (United States)

    Ammendola, Paola; Bareschino, Piero; Chirone, Riccardo; Salatino, Piero; Solimene, Roberto

    2017-06-01

    Fluidization technology displays a long record of success stories, mostly related to applications to thermal and thermochemical processes, which are fostering extension to novel and relatively unexplored fields. Application of fluidized beds to collection and thermal storage of solar radiation in Concentrated Solar Power (CSP) is one of the most promising, a field which poses challenging issues and great opportunities to fluidization scientists and technologists. The potential of this growing field calls for reconsideration of some of the typical design and operation guidelines and criteria, with the goal of exploiting the inherently good thermal performances of gas-fluidized beds at their best. "Creative" and non-conventional design and operation of fluidized beds, like those based on internal and external solids circulation, may be beneficial to the enhancement of thermal diffusivity and surface-to-bed heat transfer, improving the potential for application in the very demanding context of CSP with thermal energy storage. This paper investigated: i) a fluidized bed configuration with an uneven distribution of the fluidizing gas to promote vortices in the scale of bed height (internal solids circulation); ii) a dual fluidized bed configuration characterized by an external solids circulation achieved by the operation of a riser and a bubbling fluidized bed. CFD simulations showed the hydrodynamics conditions under which the internal solids circulation was established. The hydrodynamic characterization of the external solids circulation was achieved by an experimental study carried out with different cold models. The dual fluidized bed system was optimized in terms of operating conditions and geometrical features of the connections between two fluidized beds.

  4. 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.)

  5. Modeling of Carbochlorination of Zircon in Fluidized Bed Reactor

    Science.gov (United States)

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

    2010-02-01

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

  6. On the Influence of Particle Entrainment from an Inhomogeneous Fluidized Bed on the Hydrodynamics of the Vortex Over-Bed Zone

    Science.gov (United States)

    Pitsukha, E. A.; Teplitskii, Yu. S.

    2017-01-01

    Experimental investigation of the radial distributions of tangential air velocity and total pressure in the vortex overbed zone of a fluidized bed of diameter 0.393 m has been carried out. The influence of the entrainment of particles from the bed in the exhaust trails of gas bubbles on the maximum values of tangential velocity and total pressure has been established.

  7. 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.

  8. Fluorination of UF{sub 4} in a mini-tapered fluidized bed and mathematical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Khani, M.H., E-mail: mhkhani@aeoi.org.i [Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, P.O. Box 14395, 836 Tehran (Iran, Islamic Republic of); Ghannadi, M. [Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, P.O. Box 14395, 836 Tehran (Iran, Islamic Republic of); Pahlavanzadeh, H. [Department of Chemical Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box 11365, 8486 Tehran (Iran, Islamic Republic of)

    2010-09-15

    A mini-tapered fluidized bed reactor can be used for fluorination reaction of UF{sub 4} to produce uranium hexafluoride. By adopting the mini-tapered bed the problems associated with fluidization in a cylindrical bed such as entrainment of particles and the limitation of operating velocity can be overcome, consequently the performance of the reactor can be enhanced. Simulation of the reactor was performed employing two-phase models, bubble phase with piston flow and emulsion phase with piston (D.P-P model) or perfectly mixed flow (D.P-M model). The voidage of the emulsion and bubble phases were estimated from the distribution two-phase structure hydrodynamic model. The model predictions have been compared with the results from a pilot-scale experiment. The D.P-P model gives good agreement between computed and empirical results. The effects of various parameters on the reactor performance are discussed using the model.

  9. 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.

  10. Nucla circulating atmospheric fluidized bed demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    Keith, Raymond E.

    1991-10-01

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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Experimental and computational studies of hydrodynamics in three-phase and two-phase fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Bahary, M.

    1994-12-01

    The objective of the present study was to investigate the hydrodynamics of three-phase fluidized beds, their rheology, and experimentally verify a predictive three fluid hydrodynamic model developed at the Illinois Institute of Technology, Chicago. The recent reviews show that there exist no such models in the literature. The IIT hydrodynamic model computes the phase velocities and the volume fractions of gas, liquid, and particulate phases. Model verification involves a comparison of these computed velocities and volume fractions to experimental values. In this thesis, a three fluid model is presented. The input into the model can be particulate viscosities either measured with a Brookfield viscometer or derived using the mathematical techniques of kinetic theory of granular flows pioneered by Savage and others. The computer simulation of a three-phase fluidized bed in an asymmetric mode qualitatively predicts the gas, liquid and solid hold-ups (volume fractions) and flow patterns in the industrially important churn-turbulent (bubbly coalesced) regimes. The computations in a fluidized bed with a symmetric distributor incorrectly showed no bubble coalescence. A combination of X-ray and {gamma}-ray densitometers was used to measure the solids and the liquid volume fractions in a two dimensional bed in the bubble coalesced regime. There is a good agreement between the theory for an asymmetric distributor and the experiments.

  17. Fluidized bed dry dense medium coal beneficiation

    CSIR Research Space (South Africa)

    North, Brian C

    2017-10-01

    Full Text Available and Sons Ltd. 4. Geldart, D. 1986. Characterization of Fluidized Powders. In Geldart, D. (Ed) Gas Fluidization Technology: 33-51. Great Britain, John Wiley and Sons Ltd. 5. Kunii, D. & Levenspiel, O. 1977. Fluidization Engineering. Huntington, NY...

  18. 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

  19. 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)

  20. 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)

  1. Synthesis of carbon nanotubes using fluidized bed technology

    CSIR Research Space (South Africa)

    Swartbooi, AM

    2008-11-01

    Full Text Available virgin plastics as well as a carbonaceous gas using fluidized bed technology. Current investigations are underway to test various factors involved with the CNT growth and production. An understanding of these factors and their interactions could provide...

  2. Starch Wastewater Treatment in a Three Phase Fluidized Bed ...

    African Journals Online (AJOL)

    MICHAEL

    www.bioline.org.br/ja. Starch Wastewater Treatment in a Three Phase Fluidized Bed Bioreactor with Low. Density Biomass Support. *RAJASIMMAN, M; KARTHIKEYAN, C. Environmental Engineering Laboratory, Department of Chemical Engineering, Annamalai University. Annamalai Nagar - 608002, Tamil nadu, India.

  3. JPL in-house fluidized-bed reactor research

    Science.gov (United States)

    Rohatgi, N. K.

    1984-01-01

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

  4. Characteristic Features of Fluidization of Bidisperse Beds in Suffosion Conditions

    Science.gov (United States)

    Pitsukha, E. A.; Teplitskii, Yu. S.; Buchilko, É. K.

    2017-11-01

    Experimental investigation of fluidization of bidisperse beds of quartz sand and straw pellets at a large ratio of their equivalent diameters is carried out. The influence of the mass fraction of pellets on the rate of complete fluidization of a disperse bed has been established. The inapplicability of the available dependences, based on the use of Ergun's formula, for describing the results obtained is shown.

  5. 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.

  6. Thermal decomposition of selected chlorinated hydrocarbons during gas combustion in fluidized bed

    Science.gov (United States)

    2013-01-01

    Background The process of thermal decomposition of dichloromethane (DCM) and chlorobenzene (MCB) during the combustion in an inert, bubbling fluidized bed, supported by LPG as auxiliary fuel, have been studied. The concentration profiles of C6H5CI, CH2Cl2, CO2, CO, NOx, COCl2, CHCl3, CH3Cl, C2H2, C6H6, CH4 in the flue gases were specified versus mean bed temperature. Results The role of preheating of gaseous mixture in fluidized bed prior to its ignition inside bubbles was identified as important factor for increase the degree of conversion of DCM and MCB in low bed temperature, in comparison to similar process in the tubular reactor. Conclusions Taking into account possible combustion mechanisms, it was identified that autoignition in bubbles rather than flame propagation between bubbles is needed to achieve complete destruction of DCM and MCB. These condition occurs above 900°C causing the degree of conversion of chlorine compounds of 92-100%. PMID:23289764

  7. Thermal decomposition of selected chlorinated hydrocarbons during gas combustion in fluidized bed

    Directory of Open Access Journals (Sweden)

    Olek Malgorzata

    2013-01-01

    Full Text Available Abstract Background The process of thermal decomposition of dichloromethane (DCM and chlorobenzene (MCB during the combustion in an inert, bubbling fluidized bed, supported by LPG as auxiliary fuel, have been studied. The concentration profiles of C6H5CI, CH2Cl2, CO2, CO, NOx, COCl2, CHCl3, CH3Cl, C2H2, C6H6, CH4 in the flue gases were specified versus mean bed temperature. Results The role of preheating of gaseous mixture in fluidized bed prior to its ignition inside bubbles was identified as important factor for increase the degree of conversion of DCM and MCB in low bed temperature, in comparison to similar process in the tubular reactor. Conclusions Taking into account possible combustion mechanisms, it was identified that autoignition in bubbles rather than flame propagation between bubbles is needed to achieve complete destruction of DCM and MCB. These condition occurs above 900°C causing the degree of conversion of chlorine compounds of 92-100%.

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

    Science.gov (United States)

    Gall, Robert L.

    1981-01-01

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

  9. Stability of flows in fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, C.

    1992-01-01

    In this paper we carry out a systematic linearized stability analysis of the state of uniform fluidization for a fluid infused with granular particles. We carry out an interesting optimization procedure which leads to bounds for certain parameters, within which the state of uniform fluidization is stable. We find that this stability depends critically on the structure of the pressure-like term. (VC)

  10. A Study of the Influence of Numerical Diffusion on Gas-Solid Flow Predictions in Fluidized Beds

    Science.gov (United States)

    Ghandriz, Ronak; Sheikhi, Reza

    2015-11-01

    In this work, an investigation is made of the influence of numerical diffusion on the accuracy of gas-solid flow predictions in fluidized beds. This is an important issue particularly in bubbling fluidized beds since numerical error greatly affects the dynamics of bubbles and their associated mixing process. A bed of coal (classified as Geldart A) is considered which becomes fluidized as the velocity of nitrogen stream into the reactor is gradually increased. The fluidization process is simulated using various numerical schemes as well as grid resolutions. Simulations involve Eulerian-Eulerian two-phase flow modeling approach and results are compared with experimental data. It is shown that higher order schemes equipped with flux limiter give favorable prediction of bubble and particle dynamics and hence, the mixing process within the reactor. The excessive numerical diffusion associated with lower order schemes results in unrealistic prediction of bubble shapes and bed height. Comparison is also made of computational efficiency of various schemes. It is shown that the Monotonized Central scheme with down wind factor results in the shortest simulation time because of its efficient parallelization on distributed memory platforms.

  11. Method of feeding particulate material to a fluidized bed

    Science.gov (United States)

    Borio, Richard W.; Goodstine, Stephen L.

    1984-01-01

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

  12. Plant start-up of an atmospheric fluidized bed boiler retrofit

    Energy Technology Data Exchange (ETDEWEB)

    Follett, R.E.; Larva, W.J. (Stone and Webster Engineering Corp. (USA))

    1988-08-01

    Start up activities at the Black Dog 130 MWe atmospheric fluidized bed combustor conversion began in February 1986 and ran concurrent with the construction schedule through June 1986. During this period, the boiler casing was air tested and the water/steam circuitry was chemically cleaned. Forty six steam blows were made from drum pressures of 56.2 kg/cm{sup 2} to clean the boiler. The first fluidized bed coal fires were started on June 26, 1986, with the turbine on line and a maximum electrical power output of 45 MWe net. Gross power output as high as 95 MWe was achieved. Early in the Black Dog Unit 2 project, it was determined that only a bubbling fluidized bed combustor could be economically retrofit to the unit. Despite the limitations imposed by the project requirement to build a retrofit unit and not a completely new fluidized bed combustor, the Black Dog 2 retrofit provides operating flexibility that would be difficult to obtain with other designs. The paper describes what special design features make the operating flexibility possible and evaluates the economics of the design due to the process efficiency penalty when burning a hard Eastern coal.

  13. 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

  14. Experimental study of fluidized bed agglomeration of acerola powder

    Directory of Open Access Journals (Sweden)

    G. C. Dacanal

    2008-03-01

    Full Text Available The aim of this work was to study the main effects of acerola powder on fluidized bed agglomeration. A 2(4-1 fractional factoring design was used to evaluate the main operating conditions (fluidizing air temperature, fluidizing air velocity, atomizing air flow and height of nozzle in the bed. The mechanical and physicochemical product changes were determined by analysis of particle diameter, moisture content, wetting time and bed porosity. The particle enlargement by agglomeration occurred when the relative humidity in the bed increased and, thus, the moisture of the product increased. However, the excessive increase in relative humidity resulted in a decrease in yield, caused by caking and product incrustation. The consolidation of small granules resulted in an increase in the instant properties, decreasing the wetting time and increasing the solubility in a short period of agitation.

  15. Simulation of biomass-steam gasification in fluidized bed reactors: Model setup, comparisons and preliminary predictions.

    Science.gov (United States)

    Yan, Linbo; Lim, C Jim; Yue, Guangxi; He, Boshu; Grace, John R

    2016-12-01

    A user-defined solver integrating the solid-gas surface reactions and the multi-phase particle-in-cell (MP-PIC) approach is built based on the OpenFOAM software. The solver is tested against experiments. Then, biomass-steam gasification in a dual fluidized bed (DFB) gasifier is preliminarily predicted. It is found that the predictions agree well with the experimental results. The bed material circulation loop in the DFB can form automatically and the bed height is about 1m. The voidage gradually increases along the height of the bed zone in the bubbling fluidized bed (BFB) of the DFB. The U-bend and cyclone can separate the syngas in the BFB and the flue gas in the circulating fluidized bed. The concentration of the gasification products is relatively higher in the conical transition section, and the dry and nitrogen-free syngas at the BFB outlet is predicted to be composed of 55% H 2 , 20% CO, 20% CO 2 and 5% CH 4 . Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. 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.

  17. Concepts of Emission Reduction in Fluidized Bed Combustion of Biomass

    Directory of Open Access Journals (Sweden)

    Amon Purgar

    2012-01-01

    Full Text Available A status report on fluidized bed technology in Austria is under preparation, in response to the Fluidized Bed Conversion multi-lateral technology initiative of the International Energy Agency. This status report focuses on the current operation of fluidized bed combustors. Combustors have been installed in the following industrial sectors: pulp and paper, biomass heat and power plants, waste-to-energy plants, and communal sewage sludge treatment plants. There are also some small demonstration plants. These plants all have in common that they treat renewable fuel types. In many cases, only bio-fuels are treated. Besides the ability to burn a wide range of low-grade and difficult fuels, fluidized bed combustors have the advantages of low NOX emissions and the possibility of in-process capture of SO2. Various emission reduction concepts for fluidized bed combustors that are typical for their industrial sector are discussed. The discussion of these concepts focuses on NOX, SO2 and dust.

  18. 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...

  19. 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.

  20. Oxidative coupling of methane over a La{sub 2}O{sub 3}/CaO catalyst. Optimization of reaction conditions in a bubbling fluidized-bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mleczko, L.; Pannek, U.; Rothaemel, M.; Baerns, M. [Bochum Univ. (Germany). Technische Chemie

    1996-04-01

    Oxidative coupling of methane (OCM) over a La{sub 2}O{sub 3}/CaO catalyst was investigated in laboratory-scale fluidized-bed reactors in various ranges of reaction conditions. The catalyst proved to be a very active and selective material for OCM. It was fluidizable in the whole range of operating conditions, and catalytically stable. Axial gas concentration profiles showed that C{sub 2}+ selectivity was not only influenced by oxidative consecutive reactions, but also by steam reforming of ethylene. Two methods for improving C{sub 2}+ selectivity were tested: (1) dilution of the catalytic bed, and (2) operation with lean feed. Dilution of the catalyst led to a slight (1-2%) decrease in selectivity. Dilution of the feed gas with nitrogen resulted in a small improvement (<2%) in C{sub 2}+ selectivity. Although not currently viable economically, given certain changes in the future, this catalyst may find application in OCM, which is the potentially prospective route for the direct conversion of methane. 33 refs., 5 figs.

  1. Application of sedimentation model to uniform and segregated fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Shippy, J.L. III; Watson, J.S.

    1990-10-24

    This paper incorporates concepts of unimodal and bimodal sedimentation to develop a model that accurately predicts bed expansion during particulate fluidization. During bed expansion a particle is considered to be fluidized not by the pure fluid, but by a slurry consisting of the pure fluid and other surrounding particles. The contributions of the other surrounding particles to the additional buoyant and drag forces are accounted for with the use of effective fluid or slurry properties, density and viscosity. As bed expansion proceeds, influences of the surrounding particles decrease; therefore, these effective properties are functions of the changing void fraction of the suspension. Furthermore, the expansion index, which empirically represents the degree to which viscous and inertial forces are present, is traditionally a function of a constant terminal Reynold's number. Because the effective fluid properties are considered to be changing as fluidization proceeds, the degree to which viscous and inertial forces also changes; therefore, the expansion index is written as a function of a local or intermediate Reynold's number. These concepts are further extended to bimodal fluidization in which small or light particles aid in the fluidization of the large or heavy particles. The results indicate that the proposed model more accurately predicts particulate bed expansion for a wider range of systems (gas -- liquid, low Reynold's number -- high Reynold's number) than other analytical or empirical models.

  2. Ash behavior and de-fluidization in low temperature circulating fluidized bed biomass gasifier

    DEFF Research Database (Denmark)

    Narayan, Vikas

    ensures that high-alkali biomass fuels can be used without risks of bed de-fluidization. This thesis aims to understand the behavior of alkali metals and ash in the LTCFB system. The thesis work involved measurements made on bed material and product gas dust samples on a 100kW LTCFB gasifier placed....... It was observed that of the total fuel ash entering the system, a large fraction (40-50%) of the ash was retained in the secondary cyclone bottoms and a lower amount (8-10%) was released as dust in the exit gas; the residual ash was accumulated within the fluidized bed system. A dominant fraction of alkali......Biomass is increasingly used as a fuel for power generation. Herbaceous fuels however, contain high amounts of alkali metals which get volatilized at high temperatures and forms salts with low melting points and thus condense on pipelines, reactor surfaces and may cause de-fluidization. A Low...

  3. 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

  4. 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

  5. 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.

  6. 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)

  7. Fluidization behavior in a circulating slugging fluidized bed reactor. Part I: Residence time and residence time distribution of polyethylene solids

    NARCIS (Netherlands)

    van Putten, I.C.; van Sint Annaland, M.; Weickert, G.

    2007-01-01

    Square nosed slugging fluidization behavior in a circulating fluidized bed riser using a polyethylene powder with a very wide particle size distribution was studied. In square nosed slugging fluidization the extent of mixing of particles of different size depends on the riser diameter, gas velocity,

  8. Drag Force in a Gas Fluidized Granular Bed

    Science.gov (United States)

    Brzinski, T. A.; Durian, D. J.

    2008-03-01

    We use a rheometer to measure the torque acting on a rotating bar in a bed of gas-fluidized glass beads. We vary rotation rate from .001-10rps, vary depth from 1-10 cm, and increase the fluidizing gas flow from no flow well into the fluidized regime. We observe that at high rotation rates the drag is roughly proportional to velocity squared. At low rates we can rescale the measured torque by depth, and observe a collapse of the data. These results agree with the predictions of a granular drag force model which has proven effective in predicting granular impact dynamics. The model consists of an inertial drag term, which is depth-independent and scales as velocity squared, and a frictional drag term, which is independent of rate and varies linearly with depth. We find, as expected, that while the frictional term is airflow-dependent the inertial term is uncoupled from the fluidization.

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

    DEFF Research Database (Denmark)

    Jensen, Anker; Johnsson, Jan Erik

    1997-01-01

    -1273 K, 20-30% of the fuel-N in the form of NH3 is oxidized catalytically to N-2 over bed material and so this reaction is important for a low conversion of fuel-N to NO. The importance of the homogeneous oxidation of NH3 to NO and reduction of NO by NH3 increases with increasing temperature....... 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...... velocity, the bubble size, the bubble rise velocity and the gas interchange coefficient between bubble and dense phase. The most important combustion parameters are the rates of CO and CH4 combustion and the CO/(CO + CO2) ratio from char combustion. (C) 1997 Elsevier Science Ltd....

  10. Removal of hazardous gaseous pollutants from industrial flue gases by a novel multi-stage fluidized bed desulfurizer

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, C.R. [State Pollution Control Board, Bhubaneswar, Orissa (India); Adapala, Sivaji [Department of Chemical Engineering, Indian Institute of Technology (IIT) Kharagpur, P.O. Kharagpur Technology, Kharagpur 721302, West Bengal (India); Meikap, B.C., E-mail: bcmeikap@che.iitkgp.ernet.in [Department of Chemical Engineering, Indian Institute of Technology (IIT) Kharagpur, P.O. Kharagpur Technology, Kharagpur 721302, West Bengal (India)

    2009-06-15

    Sulfur dioxide and other sulfur compounds are generated as primary pollutants from the major industries such as sulfuric acid plants, cupper smelters, catalytic cracking units, etc. and cause acid rain. To remove the SO{sub 2} from waste flue gas a three-stage counter-current multi-stage fluidized bed adsorber was developed as desulfurization equipment and operated in continuous bubbling fluidization regime for the two-phase system. This paper represents the desulfurization of gas mixtures by chemical sorption of sulfur dioxide on porous granular calcium oxide particles in the reactor at ambient temperature. The advantages of the multi-stage fluidized bed reactor are of high mass transfer and high gas-solid residence time that can enhance the removal of acid gas at low temperature by dry method. Experiments were carried out in the bubbling fluidization regime supported by visual observation. The effects of the operating parameters such as sorbent (lime) flow rate, superficial gas velocity, and the weir height on SO{sub 2} removal efficiency in the multistage fluidized bed are reported. The results have indicated that the removal efficiency of the sulfur dioxide was found to be 65% at high solid flow rate (2.0 kg/h) corresponding to lower gas velocity (0.265 m/s), wier height of 70 mm and SO{sub 2} concentration of 500 ppm at room temperature.

  11. 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.)

  12. Technological processes intensification in devices with magneto-fluidized bed

    Directory of Open Access Journals (Sweden)

    Egorov Ivan

    2017-01-01

    Full Text Available The paper shows the efficiency of application of magneto-fluidized bed formed of ferromagnetic materials in press-forms dosed filling and milling devices. For powders without natural fluidity, dosing device is situated between electromagnets creating constant magnetic field with horizontal induction lines and alternating gradient magnetic field with vertical induction lines and higher induction gradient in the lowest part of chamber with powder. This configuration allows development of uniform efflux speed of ferromagnetic powders from 2 mm diameter opening. For example, mass efflux speed of strontium ferrite powder with 1 μm average particle size in magneto-fluidized bed reached 181.1 mg/s and the dosing time of 2000 mg of this powder was 11.1 s. For practical usage of magneto-fluidized bed in the milling device, beater mill is situated between electromagnet poles in the way that induction lines of constant and alternating gradient magnetic fields were mutually perpendicular and parallel to the plane of rotating beaters. Milling of particulate strontium ferrite with 1558.5 μm average particle size during 120 minutes in magneto-fluidized bed allows increasing milling degree in 16.2 times by comparison with processing without electromagnetic effect.

  13. Microstructure characterization of fluidized bed nitrided Fe–Si and ...

    Indian Academy of Sciences (India)

    Unknown

    gations on the nitrided samples were carried out by optical and SEM microscopic observations, X-ray diffraction and Mössbauer spectroscopy. Both the compound and diffusion layers were investigated. Keywords. Fe–Si; Fe–Si–Al foils; thermochemical nitriding treatment; fluidized-bed; structure; nitriding mechanism. 1.

  14. JPL in-house fluidized bed reactor research

    Science.gov (United States)

    Rohatgi, N. K.

    1985-01-01

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

  15. The porosity in a fluidized bed heat transfer model

    NARCIS (Netherlands)

    Visser, G; 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.

  16. Population balance modelling of fluidized bed melt granulation: an overview

    NARCIS (Netherlands)

    Tan, H.S.; Goldschmidt, M.J.V.; Boerefijn, R.; Hounslow, M.J.; Salman, A.; Kuipers, J.A.M.

    2005-01-01

    This paper presents an overview of the work undertaken by our group to identify and quantify the rates processes active in fluidized bed melt granulation (FBMG). The process involves the identification and development of physically representative models to mechanistically describe FBMG using both

  17. 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.

  18. Fluidized-Bed Gasification of Plastic Waste, Wood, and Their Blends with Coal

    OpenAIRE

    Lucio Zaccariello; Maria Laura Mastellone

    2015-01-01

    The effect of fuel composition on gasification process performance was investigated by performing mass and energy balances on a pre-pilot scale bubbling fluidized bed reactor fed with mixtures of plastic waste, wood, and coal. The fuels containing plastic waste produced less H 2 , CO, and CO 2 and more light hydrocarbons than the fuels including biomass. The lower heating value (LHV) progressively increased from 5.1 to 7.9 MJ/Nm 3 when the plastic waste fraction was moved from 0% to 100%. Hig...

  19. HYDRODYNAMIC CHARACTERISTICS OF FLUIDIZED BEDS CONTAINING LARGE POLYDISPERSED PARTICLES

    Directory of Open Access Journals (Sweden)

    TANNOUS K.

    1998-01-01

    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.

  20. Study on biomass pyrolysis and gasification in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Su, X.; Wang, Z.; Cheng, C.; Tang, S.; Lu, Z.; Li, D. [Tsinghua University, Beijing (China). Thermal Engineering Department

    2000-08-01

    Experimental investigations of biomass pyrolysis and gasification were performed in a fluidized bed reactor with steam and nitrogen as fluid medium respectively. The size of the stainless steel reactor is 150mm ID and 1360mm in height. Five biomass samples including poplar sawdust, bagasse, cotton stem, eucalyptus globulus and pinus ratiata, have been tested on the facility at the temperatures ranging from 923K to 1073K. During each test run, biomass feedstock was fed into the reactor continuously for twelve minutes and without residue discharge, meanwhile seven gas samples were taken, five during the feeding process and two after the stop of feeding. The transient and accumulated gas yields were measured with a rotameter and a gas meter. The temperatures of the fluidized bed and freeboard were acquired by a system of thermocouples connected with a computer. The gas samples were analyzed on a gas chromatograph. On the basis of the experimental results, the variations of gas yield, gas composition, energy conversion efficiency and mass conversion efficiency with temperature are discussed for each biomass feedstock in both cases of steam and nitrogen fluidization. It has been revealed in this investigation that the presence of steam in the fluidized bed reactor stimulates tar cracking to form the gas species of C{sub 2}H{sub 4}and C{sub 2}H{sub 6}, etc. 8 ref., 15 figs., 6 tabs.

  1. Modelling of dynamics of combustion of biomass in fluidized beds

    Directory of Open Access Journals (Sweden)

    Saastamoinen Jaakko J.

    2004-01-01

    Full Text Available New process concepts in energy production and biofuel, which are much more reactive than coal, call for better controllability of the combustion in circulating fluidized bed boilers. Simplified analysis describing the dynamics of combustion in fluidized bed and circulating fluidized bed boilers is presented. Simple formulas for the estimation of the responses of the burning rate and fuel inventory to changes in fuel feeding are presented. Different changes in the fuel feed, such as an impulse, step change, linear increase and cyclic variation are considered. The dynamics of the burning with a change in the feed rate depends on the fuel reactivity and particle size. The response of a fuel mixture with a wide particle size distribution can be found by summing up the effect of different fuel components and size fractions. Methods to extract reaction parameters form dynamic tests in laboratory scale reactors are discussed. The residence time of fuel particles in the bed and the resulting char inventory in the bed decrease with increasing fuel reactivity and differences between coal and biomass is studied. The char inventory affects the stability of combustion. The effect of char inventory and oscillations in the fuel feed on the oscillation of the flue gas oxygen concentration is studied by model calculation. A trend found by earlier measurements is explained by the model.

  2. 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)

  3. Reaction engineering simulations of a fluidized-bed reactor for selective oxidation of fluorene to 9-fluorenone

    Energy Technology Data Exchange (ETDEWEB)

    Mleczko, L. (Bochum Univ. (Germany). Lehrstuhl fuer Technische Chemie); Pannek, U. (Bochum Univ. (Germany). Lehrstuhl fuer Technische Chemie); Baerns, M. (Bochum Univ. (Germany). Lehrstuhl fuer Technische Chemie)

    1994-06-01

    The catalytic oxidation of fluorene to 9-fluorenone in a fluidized-bed reactor was investigated by modeling of the reactor and simulation of its performance. The ''Bubble Assemblage Model'' of Kato and Wen, the ''Bubbling Bed Model'' of Kunii and Levenspiel and the ''Countercurrent Backmixing Model'' of Potter were applied. From a comparison of simulation results obtained by the various fluidized-bed models and a fixed-bed model conclusions were drawn about the influence of interphase mass transfer and gas backmixing on the conversion of fluorene and selectivity of 9-fluorenone formation. Furthermore, the dependence of conversion and selectivity on temperature and hydrodynamic conditions was investigated. In particular, the implications of a change of hydrodynamic conditions for scale-up were analysed. The highest yield of 9-fluorenone predicted for a bench-scale fluidized bed amounted to 88% (X[sub F] = 97%, S[sub NON] = 91%). This yield was lower than in a fixed-bed reactor (Y[sub NON] = 92%, X[sub F] = 99%, S[sub NON] = 93%). A further drop of the yield was predicted when scaling-up from a bench-scale reactor to a commercial size unit (Y[sub NON] = 54%, X[sub F] = 86%, S[sub NON] = 63%). (orig.)

  4. Formation and removal of biomass-derived contaminants in fluidized-bed gasification processes

    Energy Technology Data Exchange (ETDEWEB)

    Kurkela, E. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1996-12-31

    The objectives of this thesis were to examine the effects of the feedstock and the operating conditions of a fluidized-bed gasifier on the formation of tars and nitrogen-containing compounds and to study the effectiveness of the hot gas cleaning methods developed for the removal of particulates, alkali metals, tars and nitrogen-containing compounds. The most essential part of the work was carried out in the pressurized fluidized-bed gasification test facilities composed of an air-blown bubbling fluidized-bed gasifier and subsequent hot gas filter unit. The operation pressure of the test rig could be varied in the range 0.3 - 1.0 MPa and the maximum allowable gasification temperature was 1 050 deg C. The maximum capacity with biomass fuels was 80 kg/h. A wide range of feedstocks from hard coals, lignite and peat to different wood derived fuels and straw were used in the gasification tests. Two different types of ceramic filters were tested in the filter unit connected to the pressurized fluidized-bed gasifier. The filter unit was operated in a temperature range of 400 - 740 deg C. The particulate removal requirements set by the gas turbines were met by both types of filters and with product gases derived from all the feedstocks tested. In addition to the gasification and gas filtration tests, catalytic tar and ammonia decomposition was studied using both laboratory and bench-scale test facilities. Inexpensive calcium-based bulk materials, dolomites and limestones, were efficient tar decomposition catalysts in atmospheric-pressure tests

  5. Discrete particle simulations of an electric-field enhanced fluidized bed

    NARCIS (Netherlands)

    Kleijn van Willigen, F.; Demirbas, B.; Deen, N.G.; Kuipers, J.A.M.; Ommen, J.R.

    2008-01-01

    Reducing the size of gas bubbles can significantly improve the performance of gas–solid fluidized reactors. However, such a control of bubbles is difficult to realize without measures that either use a lot of energy or deteriorate the fluidization behavior. In this paper, we present the results of

  6. Agglomeration of biomass fired fluidized bed gasifier and combustor

    Energy Technology Data Exchange (ETDEWEB)

    Mettanant, V.; Basu, P. [Dalhousie Univ., Halifax, NS (Canada). Dept. of Mechanical Engineering; Butler, J. [Greenfield Research Inc., Halifax, NS (Canada)

    2009-10-15

    As a renewable energy, biomass has the potential to supplement or replace energy produced from fossil fuel resources. However, agglomeration can occur in the fluidized bed boilers and gasifiers used to generate biomass energy. This paper discussed the theoretical and experimental results obtained during an agglomeration study of a biomass-fired fluidized bed gasifier and combustor. The mechanisms of agglomeration were studied as well as influence of various biomass components on bed materials. The study showed that agglomeration is typically caused by the formation of low melting point eutectic mixtures in the bed through a reaction of alkali materials in the fuel with silica bed materials. Agglomeration is also prompted by reactions between alkali species in ash and silica. Beds firing coffee husks, cotton husks, wastes and soy husks have the highest agglomeration problems, while peat, wood, and sewage sludge burn without agglomeration due to their low agglomeration index. The use of alternative bed materials instead of silica sands was recommended. It was concluded that the co-combustion of biomass with coal and other fuels will also prevent agglomerates from forming. 50 refs., 9 tabs., 39 figs.

  7. Fluidized-bed and packed-bed characteristics of gel beads

    NARCIS (Netherlands)

    Zessen, van E.; Tramper, J.; Rinzema, A.; Beeftink, H.H.

    2005-01-01

    A liquid-fluidized bed or packed bed with gel beads is attractive as an immobilized-cell bioreactor. The performance of such bioreactors is influenced by the physical behavior of these beads. Three different but related aspects involving the drag force between particles and liquid were studied for

  8. Heat transfer study of fluidized-bed coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Saha, S.N.; Chanda, B.C.

    A laboratory-scale air-coal burning fluidized bed (dia. 75 mm) using 0.48, 0.95, 1.4, and 2.4-mm-average-sized coal was operated varying bed temperature between 550 and 850/sup 0/C, and fluidizing gas velocity in the range 75-230 cm/sec. The overall heat transfer coefficients for two colliery coals, Singareni and Nazira were found to vary from 12x10/sup -4/ to 60x10/sup -4/ Cals/(cm/sup 2/)(Sec)(C/sup 0/). The effects of different parameters on the heat transfer coefficient are attempted to be explained scientifically. 16 references, 3 figures.

  9. 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)

  10. Fluidized Bed Sputtering for Particle and Powder Metallization

    Science.gov (United States)

    2013-04-01

    at crushing the 35-µm glass microspheres, which were instead crushed with a ceramic mortar and pestle . However, even after crushing the 35-µm...Reinforced Aluminum Alloy Matrix Composites. Journal of Materials Engineering and Performance 1993, 2 (3), 353–357. 2. Wilson, G. O.; Moore, J. S...a Vibrating Fluidized Bed. Journal of Engineering Physics and Thermophysics 1965, 9 (2), 137–139. 6. Ryzhkov, A. F.; Putrik, B. A. Formation of a

  11. 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.

  12. Laboratory studies on corrosion of materials for fluidized bed combustion applications

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1990-10-01

    An extensive corrosion test program was conducted at Argonne National Laboratory to evaluate the corrosion performance of metallic structural materials in environments that simulate both steady-state and off-normal exposure conditions anticipated in fluidized bed combustion (FBC) systems. This report discusses the possible roles of key parameters, such as sorbent and gas chemistries, metal temperature, gas cycling conditions, and alloy pretreatment, in the corrosion process. Data on scale thickness and intergranular penetration depth are presented for several alloys as a function of the chemistry of the exposure environment, deposit chemistry, and exposure time. Test results were obtained to compare the corrosion behavior of materials in the presence of reagent grade sorbent compounds and spent-bed materials from bubbling- and circulating-fluid-bed systems. Finally, the laboratory test results were compared with metal wastage information developed over the years in several fluidized bed test facilities. Metallic alloys chosen for the tests were carbon steel, Fe-2 1/4Cr-1Mo and Fe-9Cr-1Mo ferritic steels. Types 304 and 310 stainless steel, and Incoloy 800. 26 refs., 61 figs., 8 tabs.

  13. The effect of vibration on bed voidage behaviors in fluidized beds with large particles

    Directory of Open Access Journals (Sweden)

    H. Jin

    2007-09-01

    Full Text Available The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s-1, amplitude (0 mm-1 mm, bed height (0.1 m-0.4 m as well as four kinds of particles (belonging to Geldart's B and D groups. The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within ±15%, was proposed.

  14. Bed agglomeration in fluidized combustor fueled by wood and rice straw blends

    Energy Technology Data Exchange (ETDEWEB)

    Thy, P.; Lesher, C.E. [Department of Geology, University of California, One Shields Avenue, Davis, CA 95616 (United States); Jenkins, B.M.; Williams, R.B. [Department of Biological and Agricultural Engineering, University of California, One Shields Avenue, Davis, CA 95616 (United States); Bakker, R.R. [Wageningen University and Research Centre, Agrotechnology and Food Sciences Group, Postbus 17, 6700 AA Wageningen (Netherlands)

    2010-11-15

    Petrographic techniques have been used to examine bed materials from fluidized bed combustion experiments that utilized wood and rice straw fuel blends. The experiments were conducted using a laboratory-scale combustor with mullite sand beds, firing temperatures of 840 to 1030 C, and run durations of 5.5 h. A narrow continuous zone borders virtually all bed particles. The highest concentrations of potassium are found in this surface zone that also is enriched in appreciable amounts of other elements. Thin discontinuous films of adhesive cement, formed preferentially on surfaces and contact areas between bed particles, ultimately led to bed agglomeration. The interfaces and the presence of gas bubbles in the cement suggest a bonding material with a high surface tension and a liquid state. The cement films originate by filling of irregularities on individual and partially agglomerated bed particle surfaces by accumulation of liquid droplets preferentially in areas sheltered from turbulence and mechanical interaction. The composition of the film suggests melting of locally accumulated dust or aerosol mixture of ash particles and mullite. The film only locally enlarged bed particles. Large straw ash particles appear to have mostly been passively incorporated into the adhesive melt without melting or reaction. (author)

  15. Three-dimensional fluidized beds with rough spheres : Validation of a Two Fluid Model by Magnetic Particle Tracking and discrete particle simulations

    NARCIS (Netherlands)

    Yang, L.; Padding, J.T.; Buist, K. A.; Kuipers, J.

    2017-01-01

    Two fluid model simulations based on our recently introduced kinetic theory of granular flow (KTGF) for rough spheres and rough walls, are validated for the first time for full three-dimensional (3D) bubbling fluidized beds. The validation is performed by comparing with experimental data from

  16. 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...... of the solid phase from which the particle kinetic stresses were determined. The measured velocity profiles are in agreement with previous data from the full-scale boiler, i.e. showing a flat profile over the core region of the riser with a pronounced wall layer. The particle kinetic stresses are found...... to be anisotropic and strongly influenced by large scale effects originating from the bottom-bed bubbles....

  17. 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

    The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 C (900-1000 F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.'s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 C (650 F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes. The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 C (650-1000 F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a cost

  18. 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

    The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 °C (900-1000 °F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.'s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 °C (650 °F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes. The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 °C (650-1000 °F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a

  19. Application and Discussion of Dual Fluidized Bed Reactor in Biomass Energy Utilization

    Science.gov (United States)

    Guan, Haibin; Fan, Xiaoxu; Zhao, Baofeng; Yang, Liguo; Sun, Rongfeng

    2018-01-01

    As an important clean and renewable energy, biomass has a broad market prospect. The dual fluidized bed is widely used in biomass gasification technology, and has become an important way of biomass high-value utilization. This paper describes the basic principle of dual fluidized bed gasification, from the gas composition, tar content and thermal efficiency of the system point of view, analyzes and summarizes several typical dual fluidized bed biomass gasification technologies, points out the existence of gas mixing, the external heat source, catalyst development problems on gas. Finally, it is clear that the gasification of biomass in dual fluidized bed is of great industrial application and development prospect.

  20. Hydrodynamic Modelling of Municipal Solid Waste Residues in a Pilot Scale Fluidized Bed Reactor

    Directory of Open Access Journals (Sweden)

    João Cardoso

    2017-11-01

    Full Text Available The present study investigates the hydrodynamics and heat transfer behavior of municipal solid waste (MSW gasification in a pilot scale bubbling fluidized bed reactor. A multiphase 2-D numerical model following an Eulerian-Eulerian approach within the FLUENT framework was implemented. User defined functions (UDFs were coupled to improve hydrodynamics and heat transfer phenomena, and to minimize deviations between the experimental and numerical results. A grid independence study was accomplished through comparison of the bed volume fraction profiles and by reasoning the grid accuracy and computational cost. The standard deviation concept was used to determine the mixing quality indexes. Simulated results showed that UDFs improvements increased the accuracy of the mathematical model. Smaller size ratio of the MSW-dolomite mixture revealed a more uniform mixing, and larger ratios enhanced segregation. Also, increased superficial gas velocity promoted the solid particles mixing. Heat transfer within the fluidized bed showed strong dependence on the MSW solid particles sizes, with smaller particles revealing a more effective process.

  1. Pressurized fluidized bed - A technology for combined cycle power generation

    Science.gov (United States)

    Moskowitz, S.; Geffken, J.

    1981-01-01

    The production of electric power using high sulfur coal in an environmentally clean and efficient manner is a major element in this country's goal for energy independence. One coal combustion technique which has had demonstrable progress toward accomplishing this goal is the pressurized fluidized bed process. A pilot plant program sponsored by the Department of Energy to design a power generation system of 13 MWe size has been instrumental in developing the PFB technology. The paper describes the technology test programs that have been conducted to establish the design criteria and to select the design configurations and materials for the pilot plant. Over 10,000 hours of tests have demonstrated adequate fluid bed combustion characteristics, gaseous emissions levels at one-third the level permitted by EPA for NO(x) and SO2, and durability for the in-bed heat exchanger and the turbine blade materials.

  2. 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.

  3. 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.

  4. 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.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-02-01

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

  6. 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......, was proposed and compared to experimental data. The agreement between model and experimental data was fair. Experiments were also conducted with simultaneous oxidation of HCN and sulphation of seven different types of limestone. The catalytic activity of the limestones decreases to a non-zero level...

  7. A new model for two-dimensional numerical simulation of pseudo-2D gas-solids fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tingwen; Zhang, Yongmin

    2013-10-11

    Pseudo-two dimensional (pseudo-2D) fluidized beds, for which the thickness of the system is much smaller than the other two dimensions, is widely used to perform fundamental studies on bubble behavior, solids mixing, or clustering phenomenon in different gas-solids fluidization systems. The abundant data from such experimental systems are very useful for numerical model development and validation. However, it has been reported that two-dimensional (2D) computational fluid dynamic (CFD) simulations of pseudo-2D gas-solids fluidized beds usually predict poor quantitative agreement with the experimental data, especially for the solids velocity field. In this paper, a new model is proposed to improve the 2D numerical simulations of pseudo-2D gas-solids fluidized beds by properly accounting for the frictional effect of the front and back walls. Two previously reported pseudo-2D experimental systems were simulated with this model. Compared to the traditional 2D simulations, significant improvements in the numerical predictions have been observed and the predicted results are in better agreement with the available experimental data.

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

    Energy Technology Data Exchange (ETDEWEB)

    Welty, J. R.

    1984-01-01

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

  9. Experiments support an improved model for particle transport in fluidized beds.

    Science.gov (United States)

    Zhang, Huili; Kong, Weibin; Tan, Tianwei; Gilles, Flamant; Baeyens, Jan

    2017-08-31

    The upwards flow of particles in an Upflow Bubbling Fluidized Bed (UBFB) is studied experimentally and modelled from pressure drop considerations and energy loss equations. For Geldart group A powders tested, the upward solid flux, G s , in the tube can be expressed in terms of the applied superficial gas velocity, the free fall (terminal) velocity of the particles during their hindered settling, KU t , the pressure exerted at the base of the conveyor tube, and the tube length. The model expression [Formula: see text] can be used for design purposes, with K, the correction factor for hindered settling of the particles, approximately equal to 0.1 at high G s -values, but a function of the solids fraction in the upward conveying. The energy efficiency of the system increases with increasing U and G s . The model equation was tentatively applied to predict the effects of particle size, tube length and operation in Circulating Fluidized Bed mode. It is demonstrated that the UBFB is an efficient and flexible way of transporting particles upwards, with limited particle attrition or tube erosion due to the low gas velocity applied.

  10. On the hydrodynamics of membrane assisted fluidized bed reactors using X-ray analysis

    NARCIS (Netherlands)

    Helmi, A.; Wagner, E.C.; Gallucci, F.; Van Sint Annaland, Martin; van Ommen, J.R.; Mudde, R.F.

    2017-01-01

    The application of membrane assisted fluidized bed reactors for distributed energy production has generated considerable research interest during the past few years. It is widely accepted that, due to better heat and mass transfer characteristics inside fluidized bed reactors, the reactor

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

    NARCIS (Netherlands)

    de Boer, R.; Zomerman, J.J.; Hiddink, J.; Aufderheyde, J.; van Swaaij, Willibrordus Petrus Maria; 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. Application of CaO-Based Bed Material for Dual Fluidized Bed Steam Biomass Gasification

    Science.gov (United States)

    Koppatz, S.; Pfeifer, C.; Kreuzeder, A.; Soukup, G.; Hofbauer, H.

    Gasification of biomass is a suitable option for decentralized energy supply based on renewable sources in the range of up to 50 MW fuel input. The paper presents the dual fluidized bed (DFB) steam gasification process, which is applied to generate high quality and nitrogen-free product gas. Essential part of the DFB process is the bed material used in the fluidized reactors, which has significant impact on the product gas quality. By the use of catalytically active bed materials the performance of the overall process is increased, since the bed material favors reactions of the steam gasification. In particular, tar reforming reactions are favored. Within the paper, the pilot plant based on the DFB process with 100kW fuel input at Vienna University of Technology, Austria is presented. Actual investigations with focus on CaO-based bed materials (limestone) as well as with natural olivine as bed material were carried out at the pilot plant. The application of CaO-based bed material shows mainly decreased tar content in the product gas in contrast to experiments with olivine as bed material. The paper presents the results of steam gasification experiments with limestone and olivine, whereby the product gas composition as well as the tar content and the tar composition are outlined.

  13. 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.

  14. Ten residual biomass fuels for circulating fluidized-bed gasification

    Energy Technology Data Exchange (ETDEWEB)

    Drift, A. van der; Doorn, J. van [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Vermeulen, J.W. [NV Afvalzorg, Haarlem (Netherlands)

    2001-07-01

    In co-operation with a Dutch company (NV Afvalzorg) and the Dutch agency for energy and environment (Novem), ECN has successfully tested 10 different biomass residues in its 500 kW{sub th} circulating fluidized-bed gasification facility. Among the fuels used as demolition wood (both puree and mixed with sewage sludge and paper sludge), verge grass, railroad ties, cacao shells and different woody fuels. Railroad ties turn out to contain very little (heavy) metals. Initially, fuel feeding problems often impeded smooth operation. Contrary to feeding systems, the circulating fluidized-bed gasification process itself seems very flexible concerning the conversion of different kinds of biomass fuels. The fuel moisture content is one of the most important fuel characteristics. More moisture means that more air is needed to maintain the process temperature resulting in better carbon conversion and lower tar emission but also lower product gas heating value and lower cold gas efficiency. So, for a good comparison of the gasification behaviour of different fuels, the moisture content should be similar. However, the moisture content should be defined on an ash-free basis rather than on total mass (the usual way). Some of the ashes produced and retained in the second cyclone were analysed both for elemental composition and leaching behaviour. It turned out that the leaching rate of Mo and Br, elements only present in small concentrations, are preventing the ash to be considered as inert material according to the Dutch legislation for dumping on landfill sites. (Author)

  15. Contribution to fluidized bed coating of nuclear fuel particles

    Energy Technology Data Exchange (ETDEWEB)

    Haange, R. [Engineering Univ., Aachen (Germany); Gyarmati, E.; Nickel, H.

    1973-05-01

    Thesis. Submitted to Technische Hochschule, Aachen (West Germany). In a fluidized bed of a conical 3-inch coating furnace, temperature gradients were studied along with zones of deposition and the composition of the gas mixture in and above the bed. Measurements using thermocouples as well as theoretical considerations are the basis of a model defining the temperature distribution in relation to the particles and the gas composition across the bed. Thermal equilibrium was found to exist between the incoming gas and the bed of particles beyond a short heating stage above the nozzle system. No significant axial temperature gradients were detected here; radial temperature gradients remain small (<20 deg C). Zones of deposition were defined by thickness measurements carried out on the pyrocarbon deposits obtained on small fixed rods mounted in the bed. Comparison of plasma-oxidized pyrocarbon deposits on particles and fixed rods demonstrates the strong influence of particle movement and gas velocity on the structure of the pyrocarbon. Gas was sampled in the reaction zone by a suction method using small graphite tubes. The samples were analyzed by gas chromatography and mass spectrometry. Gas analysis results compared with calculated gas composition at thermodynamic equilibrium indicate that the composition approaches that of equilibrium above the heating stage. (auth)

  16. 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.

  17. Numerical simulation of gas-solid flows in fluidized bed with TFM model

    Science.gov (United States)

    Stanly, Ronith; Shoev, Georgy; Kokhanchik A., A.

    2017-10-01

    This work evaluates the effectiveness of the Two-Fluid Model (TFM) to simulate gas flows with dense particles by using a simplified Fluidized Bed as a test case. The overarching objective is to check the prediction accuracy of the TFM Model. This document includes the simulations performed using two drag models, namely Gidaspow and Syamlal-O'Brien, using Ansys Fluent 18.1. The bubble evolution as well as the time-averaged volume-fraction distributions have been compared with prior simulations conducted using MFIX, Barracuda and also with experimental data found in literature. Though the low computational requirements and capability to produce reasonable time-averaged results makes TFM a better choice for industrial applications, the low prediction accuracy for the instantaneous quantities often renders it unsuitable for more scientifically demanding studies. Hence, this work aims at a critical evaluation of the TFM model for the specified test problem.

  18. Effect of bed particles to combustion of gases in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Raiko, R.; Wallen, V.; Etelaeaho, R.; Correia, S. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

    1997-10-01

    The objective of this project was to obtain experimental data on effects of sand particles to the combustion of gases. The effect of the surface area of the particles was tested using different sized particles. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 42 mm surrounded by an electric heater. The test rig was built in the Laboratory of Energy and Process Engineering at Tampere University of Technology. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies were conducted with both fresh bed particles and used bed particles. These measurements indicate that carbon monoxide significantly reacts with oxygen in the particulate or emulsion phase of a fluidized bed, if the residence time is long enough. The reaction rate depends mainly on temperature, air coefficient, residence time and particle size of the solids. It seems that the combustion enhances if the average particle size increases. Whether this is caused by increased free path length or reduced specific surface area of the bed is yet unknown. The first might be more probable cause because the majority of reactions often took place in the freeboard right above the bed. It was clear that the bed hindered proper combustion in several cases. (orig.)

  19. Single-particle behaviour in circulating fluidized beds

    DEFF Research Database (Denmark)

    Erik Weinell, Claus; 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....... A radioactive tracking facility, which detects single radioactive particles, is developed and applied to determine the dynamic picture of the particle trajectories in the simulated boiler. The tracer particles are observed to move between the zone above and below the secondary air inlet with a mean frequency...... of about 1 Hz under the present operating conditions. This relatively high frequency is due to the fact that most of the particle trajectories take place just around the secondary air inlet. It is found that the upward particle velocity in the upper dilute transport zone decreases with the particle size...

  20. Fluidized-bed steam methane reforming with oxygen input

    Energy Technology Data Exchange (ETDEWEB)

    Roy, S.; Pruden, B.B. [University of Calgary, Alberta (Canada). Dept. of Chemical and Petroluem Engineering; Adris, A.M. [SABIC R and D, Riyadh (Saudi Arabia). Dept. of Research and Technology Support; Grace, J.R.; Lim, C.J. [University of British Columbia, Vancouver (Canada). Dept. of Chemical Engineering

    1999-07-01

    A study was undertaken to determine whether oxygen could be added directly to a fluidized bed of catalyst to provide all of the endothermic heat for the reforming reaction. It is shown that oxygen can be successfully introduced onto a reforming reactor to provide for the endothermic heat of reforming reactions. The methane conversion increased with increasing reactor temperature, oxygen input flow rate and steam-methane ratio and decreased with increasing reactor pressure as expected. Methane conversion and hydrogen yield are compared to those expected at equilibrium. There was 100% conversion of oxygen under all conditions. Most experimental runs reached and maintained autothermal conditions. The hydrogen yield increased with increasing temperature and steam-methane ratio. The hydrogen yield decreased minimally with increasing reactor pressure and oxygen flowrate. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

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

  2. 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.

  3. Granulation of acetaminophen by a rotating fluidized-bed granulator.

    Science.gov (United States)

    Kawaguchi, T; Sunada, H; Yonezawa, Y; Danjo, K; Hasegawa, M; Makino, T; Sakamoto, H; Fujita, K; Tanino, T; Kokubo, H

    2000-01-01

    The purpose of this research was to evaluate the use of a rotating fluidized-bed granulator to produce acetaminophen granules with sufficient binding force between particles and good plasticity in tablets. Ethenzamide and ascorbic acid were used to compare the relationship between granulation and the sample wetness. It was revealed that a blade rotation rate of 300 rpm, inlet air flow rate of 42 m3/hr, and spraying pressure of 1.5 kg/cm3 produced tablets with the best properties. The granule and tablet properties of ethenzamide and ascorbic acid were compared to those of acetaminophen. These compounds showed different wetting behaviors with water and different compression behaviors. With an increase in medicament content, tablet hardness increased except for the ascorbic acid formulation. Capping and sticking were observed in acetaminophen and in ascorbic acid, respectively, and acetaminophen and ethenzamide showed prolonged disintegration time.

  4. 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...

  5. 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...... (KCl) crystals with ethylcellulose (EC). Vibrations were measured with two different types of accelerometers. Different positions for placing the accelerometers and two different product containers were included in the study. Top spray coating of KCl was chosen as a ‘worst case' scenario from a coating...... point perspective. The acoustic monitoring has the potential of summarising the commonly used means to monitor the coating process. The best partial least squares (PLS) regressions, obtained by the high frequency accelerometer, showed for the release a correlation coefficient of 0.92 and a root mean...

  6. 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.

  7. Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Whitty

    2007-06-30

    University of Utah's project entitled 'Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer' (DOE Cooperative Agreement DE-FC26-02NT41490) was developed in response to a solicitation released by the U.S. Department of Energy in December 2001, requesting proposals for projects targeted towards black liquor/biomass gasification technology support research and development. Specifically, the solicitation was seeking projects that would provide technical support for Department of Energy supported black liquor and biomass gasification demonstration projects under development at the time.

  8. Thermodynamic analysis of fluidized bed drying of carrot cubes

    Energy Technology Data Exchange (ETDEWEB)

    Nazghelichi, Tayyeb; Kianmehr, Mohammad Hossein; Aghbashlo, Mortaza [Department of Agrotechnology, College of Abouraihan, University of Tehran, P.O. Box 33955-159, Pakdasht (Iran, Islamic Republic of)

    2010-12-15

    In this study, the energy and exergy analyses of fluidized bed drying of carrot cubes were investigated. Drying experiments were conducted at inlet air temperatures of 50, 60, and 70 C, BD (bed depths) of 30, 60, and 90 mm and square-cubed carrot dimensions of 4, 7, and 10 mm. The effects of drying variables on energy utilization, energy utilization ratio, exergy loss and exergy efficiency were studied. The energy utilization and energy utilization ratio varied between 0.105-1.949 kJ/s and 0.074-0.486, respectively. The exergy loss and exergy efficiency were found to be in the range of 0.206-1.612 kJ/s and 0.103-0.707, respectively. The results showed that small particles, deep beds and high inlet air temperatures increased energy utilization, energy utilization ratio, and exergy loss due to high value of heat and mass transfer. Also, the exergy efficiency had maximum value when higher drying air temperature, larger CS (cube size) and shorter BD were used for drying experiment. (author)

  9. Durability Testing of Fluidized Bed Steam Reforming Products

    Energy Technology Data Exchange (ETDEWEB)

    JANTZEN, CAROL M.; PAREIZS, JOHN M.; LORIER, TROY H.; MARRA, JAMES C.

    2005-07-01

    Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of radioactive wastes but especially aqueous high sodium wastes at the Hanford site, at the Idaho National Laboratory (INL), and at the Savannah River Site (SRS). The FBSR technology converts organic compounds to CO{sub 2} and H{sub 2}O, converts nitrate/nitrite species to N{sub 2}, and produces a solid residue through reactions with superheated steam, the fluidizing media. If clay is added during processing a ''mineralized'' granular waste form can be produced. The mineral components of the waste form are primarily Na-Al-Si (NAS) feldspathoid minerals with cage-like and ring structures and iron bearing spinel minerals. The cage and ring structured minerals atomically bond radionuclides like Tc{sup 99} and Cs{sup 137} and anions such as SO{sub 4}, I, F, and Cl. The spinel minerals appear to stabilize Resource Conservation and Recovery Act (RCRA) hazardous species such as Cr and Ni. Durability testing of the FBSR products was performed using ASTM C1285 (Product Consistency Test) and the Environmental Protection Agency (EPA) Toxic Characteristic Leaching Procedure (TCLP). The FBSR mineral products (bed and fines) evaluated in this study were found to be two orders of magnitude more durable than the Hanford Low Activity Waste (LAW) glass requirement of 2 g/m{sup 2} release of Na{sup +}. The PCT responses for the FBSR samples tested were consistent with results from previous FBSR Hanford LAW product testing. Differences in the response can be explained by the minerals formed and their effects on PCT leachate chemistry.

  10. 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.

  11. Agglomeration of bed material: Influence on efficiency of biofuel fluidized bed boiler

    Directory of Open Access Journals (Sweden)

    Ryabov Georgy A.

    2003-01-01

    Full Text Available The successful design and operation of a fluidized bed combustor requires the ability to control and mitigate ash-related problems. The main ash-related problem of biomass filing boiler is agglomeration. The fluidized bed boiler with steam capacity of 66 t/h (4 MPa, 440 °C was started up at the Arkhangelsk Paper-Pi dp-Plant in 2001. This boiler was manufactured by the Russian companies "Energosofin" and "Belenergomash" and installed instead of the existing boiler with mechanical grate. Some constructional elements and steam drum of existing boiler remained unchanged. The primary air fan was installed past the common air fan, which supply part of the air into 24 secondary airports. First operating period shows that the bed material is expanded and then operator should increase the primary air rate, and the boiler efficiency dramatically decreases. Tills paper presents some results of our investigations of fuel, bed and fly ash chemical compositions and other characteristics. Special experiments were carried out to optimize the bed drain flow rate. The influence of secondly air supply improvement on mixing with the main flow and boiler efficiency are given.

  12. 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.

  13. A process to produce effervescent tablets: fluidized bed dryer melt granulation.

    Science.gov (United States)

    Yanze, F M; Duru, C; Jacob, M

    2000-11-01

    The purpose of the present study was to apply melt granulation in a fluidized bed dryer (fluidized bed dryer melt granulation) to manufacture one-step effervescent granules composed of anhydrous citric acid and sodium bicarbonate to make tablets. This study permitted us to establish that such process parameters as concentrations of polyethylene glycol (PEG) 6000, residence times in the fluidized bed dryer, fineness of PEG6000, fineness of initial mixture effervescent systems, and efficiency of two lubricants markedly affect some granule and tablet characteristics. It is a dry process that is simple, rapid, effective, economical, reproducible, and particularly adapted to produce effervescent granules that are easily compressed into effervescent tablets.

  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. DEM Study of Wet Cohesive Particles in the Presence of Liquid Bridges in a Gas Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Yurong He

    2014-01-01

    Full Text Available A modified discrete element method (DEM was constructed by compositing an additional liquid-bridge module into the traditional soft-sphere interaction model. Simulations of particles with and without liquid bridges are conducted in a bubbling fluidized bed. The geometry of the simulated bed is the same as the one in Müller’s experiment (Müller et al., 2008. A comparison between the dry and the wet particular systems is carried out on the bubble behavior, the bed fluctuation, and the mixing process. The bubble in the dry system possesses a regular round shape and falling of scattered particles exists while the bubble boundary of the wet particles becomes rough with branches of agglomerates stretching into it. The mixing of the dry system is quicker than that of the wet system. Several interparticle liquid contents are applied in this work to find their influence on the kinetic characteristic of the wet particle flow. With an increase of liquid content, the mixing process costs more time to be completed. Symmetrical profiles of the velocity and granular temperature are found for two low liquid contents (0.001% and 0.01%, while it is antisymmetrical for the highest liquid content (0.1%.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Numerical simulation of a full-loop circulating fluidized bed under different operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yupeng [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Musser, Jordan M. [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Li, Tingwen [National Energy Technology Lab. (NETL), Morgantown, WV (United States); AECOM, Morgantown, WV (United States); Rogers, William A. [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2017-10-17

    Both experimental and computational studies of the fluidization of high-density polyethylene (HDPE) particles in a small-scale full-loop circulating fluidized bed are conducted. Experimental measurements of pressure drop are taken at different locations along the bed. The solids circulation rate is measured with an advanced Particle Image Velocimetry (PIV) technique. The bed height of the quasi-static region in the standpipe is also measured. Comparative numerical simulations are performed with a Computational Fluid Dynamics solver utilizing a Discrete Element Method (CFD-DEM). This paper reports a detailed and direct comparison between CFD-DEM results and experimental data for realistic gas-solid fluidization in a full-loop circulating fluidized bed system. The comparison reveals good agreement with respect to system component pressure drop and inventory height in the standpipe. In addition, the effect of different drag laws applied within the CFD simulation is examined and compared with experimental results.

  2. Multi-scale CFD simulation of hydrodynamics and cracking reactions in fixed fluidized bed reactors

    National Research Council Canada - National Science Library

    Zhang, Jin H; Wang, Zhen B; Zhao, Hui; Tian, Yuan Y; Shan, Hong H; Yang, Chao H

    2015-01-01

    ...–solid flow and cracking reactions. The gas mixing and particle volume fraction distributions, as well as product yields in the conventional and modified fixed fluidized bed reactors were analyzed...

  3. 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).

  4. Atmospheric Fluidized Bed Combustion testing of North Dakota lignite

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-05-01

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

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

    OpenAIRE

    de Boer, R.; Zomerman, J.J.; Hiddink, J.; Aufderheyde, J.; van Swaaij, Willibrordus Petrus Maria; 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 preferable, since they caused little damage to the membrane. Only with the larger glass beads (3 mm) did the membrane skin become corrugated, so that the rejection decreased. The permeate flux for ...

  6. Reactor modeling and physicochemical properties characterization for a polyethylene fluidized bed reactor

    OpenAIRE

    Fernandes, F.A.N.; LONA BATISTA,L. M. F.

    1999-01-01

    A new steady state model for the fluidized bed reactor and a physicochemical characterization model were developed for the simulation of polyethylene production using gas-phase technology. The association of these models was done in order to predict the characteristics of the polymer produced in the fluidized bed reactor (molecular weight, polydispersity, melt index, and other characteristics) throughout the reactor and also to predict the growth of the polymer particle.

  7. 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.

  8. Comparative simulation study of gas-phase propylene polymerization in fluidized bed reactors using aspen polymers and two phase models

    Directory of Open Access Journals (Sweden)

    Shamiria Ahmad

    2013-01-01

    Full Text Available A comparative study describing gas-phase propylene polymerization in fluidized-bed reactors using Ziegler-Natta catalyst is presented. The reactor behavior was explained using a two-phase model (which is based on principles of fluidization as well as simulation using the Aspen Polymers process simulator. The two-phase reactor model accounts for the emulsion and bubble phases which contain different portions of catalysts with the polymerization occurring in both phases. Both models predict production rate, molecular weight, polydispersity index (PDI and melt flow index (MFI of the polymer. We used both models to investigate the effect of important polymerization parameters, namely catalyst feed rate and hydrogen concentration, on the product polypropylene properties, such as production rate, molecular weight, PDI and MFI. Both the two-phase model and Aspen Polymers simulator showed good agreement in terms of production rate. However, the models differed in their predictions for weight-average molecular weight, PDI and MFI. Based on these results, we propose incorporating the missing hydrodynamic effects into Aspen Polymers to provide a more realistic understanding of the phenomena encountered in fluidized bed reactors for polyolefin production.

  9. Modeling the operation of a three-stage fluidized bed reactor for removing CO2 from flue gases.

    Science.gov (United States)

    Mohanty, C R; Meikap, B C

    2011-03-15

    A bubbling counter-current multistage fluidized bed reactor for the sorption of carbon dioxide (CO(2)) by hydrated lime particles was simulated employing a two-phase model, with the bubble phase assumed to be in plug flow, and the emulsion phase in plug flow and perfectly mixed flow conditions. To meet prescribed permissible limit to emit carbon dioxide from industrial flue gases, dry scrubbing of CO(2) was realized. For the evaluation, a pilot plant was built, on which also the removal efficiency of CO(2) was verified at different solids flow rates. The model results were compared with experimental data in terms of percentage removal efficiency of carbon dioxide. The comparison showed that the EGPF model agreed well with the experimental data satisfactorily. The removal efficiency was observed to be mainly influenced by flow rates of adsorbent and CO(2) concentration. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Mixing Behaviors of Wet Granular Materials in a Pulsating Fluidized Bed

    Science.gov (United States)

    Lim, Eldin Wee Chuan

    2017-11-01

    The Discrete Element Method combined with Computational Fluid Dynamics was coupled with a capillary liquid bridge force model for computational studies of mixing behaviors in a gas fluidized bed containing wet granular materials. There was a high tendency for wet particles to form large agglomerates within which relative motions between adjacent particles were hindered. This resulted in much lower mixing efficiencies compared with fluidization of dry particles. Capillary liquid bridge forces were on average stronger than both fluid drag forces and particle-particle collision forces. Particle exchange between agglomerates was necessary for mixing to occur during fluidization of wet granular materials but required strong capillary liquid bridge forces to be overcome. When pulsation of the inlet gas flow was applied, voidage waves comprising regions of high and low particle concentration formed within the fluidized bed. This allowed particles to cluster and disperse repeatedly, thus facilitating exchange of particles between agglomerates and promoting mixing of particles throughout the fluidized bed. This points towards the possibility of utilizing pulsed fluidization as an effective means of improving mixing efficiencies in fluidized bed systems containing wet granular materials.

  11. Lateral and vertical thermal diffusivities in a dense fluidized bed with tubes bundle

    Energy Technology Data Exchange (ETDEWEB)

    Collantes, M.A.; Martin, G.; Le Gal, J.H. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)

    1995-07-01

    Dense fluidized beds are acknowledge as homogeneous systems from both temperature and composition aspects. However, some situation such as very large units or fluidized beds with tubes bundle lead to thermal gradients within the bed. These thermal gradients are due to solids motion limitation and may have detrimental effects on the process. This paper relates investigations aiming an determining lateral and vertical thermal diffusivities in a dense fluidized bed with an without a tubes bundle. These investigations have been carried out with an experimental setup of significant size (bed size = 0.6 x 1.1 x 1.3) and with small particles (less 500 microns) so as to fill some gaps of the literature. Thermal diffusivities have been deduced from temperature gradients measured between a hot wall and a cold wall in a perpendicular fluidized bed and by applying a conventional 2-D conduction model. Lateral thermal conductivities as well as vertical thermal conductivities increase with the gas velocity and the height of the bed, and when the particle size decreases. Immersing a vertical tube bundle into the fluidized bed leads to a significant reduction of the lateral thermal diffusivity, while there is no effect on the vertical thermal diffusivity. Correlations have been drawn from the experimental results. They would have to be applied for calculation of any system running at gas velocity ranging from 0.05 to 0.3 m/s and with particle size between 50 and 300 microns. (authors). 14 refs., 14 figs., 2 tabs.

  12. A techno-economic comparison of fluidized bed gasification of two mixed plastic wastes.

    Science.gov (United States)

    Arena, U; Di Gregorio, F; Amorese, C; Mastellone, M L

    2011-07-01

    A comparison between the most promising design configurations for the industrial application of gasification based, plastics-to-energy cogenerators in the 2-6 MWe range is presented. A pilot scale bubbling fluidized bed air gasifier, having a feeding capacity of 100 kg/h, provided experimental data: the syngas complete composition, the characterization of the bed material, the entrained fines collected at the cyclone and the purge material from the scrubber. Mass and energy balances and material and substance flow analyses have been therefore drawn to assess and compare design solutions utilizing two mixed plastic wastes (MPW) obtained from separate collection of plastic packaging, after different levels of pre-treatments. The related techno-economic performances have been finally estimated on the basis of the manufacturer's specifications. The study concludes that the MPW obtained after a very simple pre-treatment and fed to a gasifier coupled with a steam turbine is the solution that currently offers the higher reliability and provides the higher internal rate of return for the investigated range of electrical energy production. Copyright © 2011. Published by Elsevier Ltd.

  13. Scale-up of an electrical capacitance tomography sensor for imaging pharmaceutical fluidized beds and validation by computational fluid dynamics

    Science.gov (United States)

    Wang, Haigang; Yang, Wuqiang

    2011-10-01

    The aim of this research is to apply electrical capacitance tomography (ECT) in pharmaceutical fluidized beds and scale up the application of ECT from a lab-scale fluidized bed to a production-scale fluidized bed. The objective is to optimize the design of the production-scale fluidized bed and to improve the operation efficiency of the fluidization processes. This is the first time that ECT has been scaled up to a production-scale fluidized bed of 1.0 m diameter and batch process capacity of 100 kg in a real industrial environment. With a large-scale fluidized bed in a real industrial environment, some key issues on the ECT sensor design must be addressed. To validate ECT measurement results, a two-phase flow model has been used to simulate the process in a lab-scale and pilot-scale fluidized bed. The key process parameters include solid concentration, average concentration profiles, the frequency spectrum of signal fluctuation obtained by the fast Fourier transfer (FFT) and multi-level wavelet decomposition in the time domain. The results show different hydrodynamic behaviour of fluidized beds of different scales. The time-averaged parameters from ECT and computational fluid dynamics are compared. Future work on the ECT sensor design for large-scale fluidized beds are given in the end of the paper.

  14. 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)

  15. 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.

  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. 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.

  18. 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.

  19. Conceptual design of a fluidized bed combustor for volume reduction of waste

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.K.; Morris, G.J.; Atkinson, C.M.; Clark, N.N.; Gautam, M.; Loth, J.L.; Zhang, G.Q.; Zhang, L.M.; Kono, H.O.

    1992-06-01

    A group of research engineers was assembled to investigate novel fluidized bed combustion systems for incinerating low-level radioactive wastes. The goal of this project was to significantly reduce the volume of these wastes in an efficient and environmentally safe manner. The process is to be limited by a maximum temperature of 600 {degrees}C and the waste product was to contain a minimum of waste material produced by the process itself (refractory, absorbents, catalysts, etc.). The approach presented in this study is to evaluate: (1) a modification of the existing system, (2) a hybrid reactor concept, and (3) a fast circulating reactor concept. Carbon dioxide and oxygen were to be the only gases introduced into the reactors. The results of this study indicate that the existing system may be more efficient with gas and solids recirculation; however, two beds are required. The hybrid reactor concept involves a bubbling bed and a fast bed in one reactor. Although a simple operation is envisioned for this system, there are several technical questions which must be addressed in order to optimize the system for a final analysis. The fast circulating reactor concept also appears to represent a simple system to operate; however, it also presents several technical questions which must be addressed before a thorough evaluation of this concept may be completed. In conclusion, this report represents a first evaluation of new concepts for significant volume reduction of low-level radioactive wastes. The technical issues required for a complete evaluation of these concepts are presented. A future research effort is outlined the result of which should significantly increase our knowledge of these issues.

  20. Studies on thermoelectric power generation consuming municipal solid waste (MSW) and using bubbling fluidized bed gasifier : Estudos em geração termelétrica a partir de resíduos sólidos urbanos (RSU) utilizando gaseificadores de leito fluidizado borbulhante

    OpenAIRE

    Andres Felipe Rodriguez Torres

    2016-01-01

    Resumo: O presente trabalho introduz novos desenvolvimentos da estratégia no conceito Fuel-Slurry Integrated Gasifier/Gas Turbine para a geração de potência termoelétrica aplicada ao caso de Resíduos Sólidos Urbanos (RSU). O processo FSIG/GT permite a alimentação do combustível num gaseificador pressurizado utilizando bombas de lama disponíveis no mercado, evitando a necessidade de sistemas de silos em cascata. O gaseificador opera em regime de Leito Fluidizado Borbulhante (Bubbling Fluidized...

  1. Oxidative decomposition of methanol in a vibroacoustic fluidized bed of Ag-coated cenosphere core-shell catalyst

    OpenAIRE

    Berkowicz Gabriela; Żukowski Witold; Baron Jerzy

    2016-01-01

    The paper presents results of a study of oxidative decomposition of methanol in a fluidized bed of silver catalyst. The process of methanol oxidation was carried out on Ag-coated cenospheres core-shell catalyst. The catalyst was obtained by precipitation of silver from methanolic solution of silver nitrate on cenospheres. Cenospheres are lightweight, inert, hollow spheres, which can be easily introduced into a fluidized bed. Application of the catalyst in a form of fluidized bed should ensure...

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

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. of Texas, El Paso, TX (United States). Dept. of Mechanical Engineering

    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

  3. [Configuration of pyrolytic chars from waste tires in fluidized bed reactor].

    Science.gov (United States)

    Jin, Yu-qi; Yan, Jian-hua; Gu, Jie-yuan; Cen, Ke-fa

    2004-11-01

    With the fluidized bed as main reactor, the configuration of chars of waste tire was investigated. The change of specific surface area, porosity and specific pore volume of chars received at various temperature, diameter of bed materials and superficial fluidization number was mainly researched. The specific surface area and porosity of chars had the peak value at 650 degrees C or 750 degrees C, which showed there exists the best pyrolysis temperature from the angle of char quality and it will decrease with smaller diameter of bed materials, 0.135-0.304mm. The porosity of chars decreases with the fluidization number increasing. The change tendency of the specific surface area of chars with the fluidization number is correlated with the pyrolysis temperature. At 550 degrees C the specific surface area of chars decreases with the fluidization number increasing, while at 650 degrees C the other way round. The change tendency of the specific pore volume of chars with the temperature is correlated with the diameter of bed materials. With larger bed materials (0.304-0.4mm), the specific pore volume of chars rises at fisrt, then decreases with the temperature increasing, and with smaller bed materials, it decreases with the temperature increasing.

  4. Potential approaches to improve gasification of high water content biomass rich in cellulose in dual fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Li; Xu, Guangwen [State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (China); Suda, Toshiyuki [Research Laboratory, IHI Corporation, Ltd., Yokohama (Japan); Murakami, Takahiro [National Institute of Advanced Science and Technology, Tsukuba (Japan)

    2010-08-15

    Biomass containing water of 30-65 wt.% and rich in cellulose, such as various grounds of drinking materials and the lees of spirit and vinegar, is not suitable for biological digestion, and the thermal conversion approach has to be applied to its conversion into bioenergy. The authors have recently worked on converting such biomass into middle heating-value gas via dual fluidized bed gasification (DFBG) integrated with various process intensification technologies. This article is devoted to highlighting those technical ways, including the choice of the superior technical deployment for a DFBG system, the impregnation of Ca onto fuel in fuel drying, the integration of gas cleaning with fuel gasification via two-stage DFBG (T-DFBG), and the decoupling of fuel drying/pyrolysis and char gasification via the decoupled DFBG (D-DFBG). The attained results demonstrated that the superior deployment of bed combination for the DFBG should be a bubbling/turbulent fluidized bed gasifier integrated with a pneumatic riser combustor. In terms of improving efficiency of fuel conversion into combustible gas and suppressing tar generation during gasification, the impregnation of Ca onto fuel exhibited distinctively high upgrading effect, while both the T-DFBG and D-DFBG were also demonstrated to be effective to a certain degree. (author)

  5. On the Hydrodynamics of an Inhomogeneous Fluidized Bed with Vertical Organization of the over-Bed Space

    Science.gov (United States)

    Pitsukha, E. A.; Teplitskii, Yu. S.; Borodulya, V. A.

    2014-09-01

    An experimental investigation of the hydrodynamics of the vortex space over a fluidized bed in a chamber of diameter 0.393 m has been carried out. The existence of two regimes associated with the size of the outlet hole has been established: the regime of a swirling air flow without a noticeable sweeping of particles from the bed and the regime with particle entrainment from the bed.

  6. Selective catalytic reduction of nitrogen oxide with ammonia in a novel reactor called the floating gas-solid fluidized bed

    NARCIS (Netherlands)

    Kwant, G.J.; Kwant, G.J.; Prins, W.; van Swaaij, Willibrordus Petrus Maria

    1995-01-01

    The floating gas-solid fluidized bed (FGSFB) is a new type of gas-solid contacting device described earlier by Kwant et al. (Fluidization VII, Proc. 7th Engng Foud. Conf. on Fluidization, Brisbane, May, 1992). It is a tapered column provided with several coarse grids, in which catalyst particles are

  7. 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.

  8. 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...... in the combustion chamber and the cyclone was calculated taking three mechanisms into account: Reduction by char, catalytic decomposition over bed material and thermal decomposition. The calculated destruction rate was in good agreement with the measured destruction of N2O injected at different levels in the boiler...

  9. 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 qua...

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

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2006-01-06

    Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of high sodium aqueous radioactive wastes. The addition of clay and a catalyst as co-reactants converts high sodium aqueous low activity wastes (LAW) such as those existing at the Hanford and Idaho DOE sites to a granular ''mineralized'' waste form that may be made into a monolith form if necessary. Simulant Hanford and Idaho high sodium wastes were processed in a pilot scale FBSR at Science Applications International Corporation (SAIC) Science and Technology Applications Research (STAR) facility in Idaho Falls, ID. Granular mineral waste forms were made from (1) a basic Hanford Envelope A low-activity waste (LAW) simulant and (2) an acidic INL simulant commonly referred to as sodium-bearing waste (SBW). The FBSR waste forms were characterized and the durability tested via ASTM C1285 (Product Consistency Test), the Environmental Protection Agency (EPA) Toxic Characteristic Leaching Procedure (TCLP), and the Single Pass Flow Through (SPFT) test. The durability of the FBSR waste form products was tested in order to compare the measured durability to previous FBSR waste form testing on Hanford Envelope C waste forms that were made by THOR Treatment Technologies (TTT) and to compare the FBSR durability to vitreous LAW waste forms, specifically the Hanford low activity waste (LAW) glass known as the Low-activity Reference Material (LRM). The durability of the FBSR waste form is comparable to that of the LRM glass for the test responses studied.

  11. 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.

  12. [Thermal energy utilization analysis and energy conservation measures of fluidized bed dryer].

    Science.gov (United States)

    Xing, Liming; Zhao, Zhengsheng

    2012-07-01

    To propose measures for enhancing thermal energy utilization by analyzing drying process and operation principle of fluidized bed dryers,in order to guide optimization and upgrade of fluidized bed drying equipment. Through a systematic analysis on drying process and operation principle of fluidized beds,the energy conservation law was adopted to calculate thermal energy of dryers. The thermal energy of fluidized bed dryers is mainly used to make up for thermal consumption of water evaporation (Qw), hot air from outlet equipment (Qe), thermal consumption for heating and drying wet materials (Qm) and heat dissipation to surroundings through hot air pipelines and cyclone separators. Effective measures and major approaches to enhance thermal energy utilization of fluidized bed dryers were to reduce exhaust gas out by the loss of heat Qe, recycle dryer export air quantity of heat, preserve heat for dry towers, hot air pipes and cyclone separators, dehumidify clean air in inlets and reasonably control drying time and air temperature. Such technical parameters such air supply rate, air inlet temperature and humidity, material temperature and outlet temperature and humidity are set and controlled to effectively save energy during the drying process and reduce the production cost.

  13. Treatment of N-Nitrosodimethylamine (NDMA) in Groundwater Using a Fluidized Bed Bioreactor

    Science.gov (United States)

    2014-01-01

    media to create a biofilm , and perform an oxidation/reduction reaction in consuming the dissolved oxygen (DO) and propane. The NDMA is removed by R...consist of one full-scale fluidized bed bioreactor, constructed with welded, 304 stainless steel to API-650 with sidewall anchor chairs; closed top design...and full stainless steel flat floor plate with access ladder; and a deck grating and handrail on roof. Included with the FBR is a fluidization pump

  14. The effects of agglomeration/defluidization on emission of heavy metals for various fluidized parameters in fluidized-bed incineration

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chiou-Liang; Tsai, Ming-Chih; Chang, Chih-Hung [Department of Civil and Environmental Engineering, National University of Kaohsiung, Kaohsiung, 811 (China)

    2010-01-15

    The agglomeration/defluidization may be produced to generate the secondary pollutant during incineration. However, the effects of agglomeration/defluidization on heavy metal distribution have rarely been examined. Therefore, the effects of the agglomeration/defluidization process on heavy metal emission in flue gas are studied. The artificial waste is employed to simulate municipal waste and to form agglomerates, which contain alkali metals, earth alkali metals, a mixture of metals (Pb, Cr and Cd) and sawdust. The fluidized parameters (including gas velocity, sand particle size and static bed height) are varied to determine their influences on heavy metal emission. The results indicate that addition of Na increases the risk of agglomeration/defluidization, but the emission concentration of heavy metals decreases during agglomeration/defluidization. The heavy metals may react with Na to form the eutectics or are covered and adhered by the liquid-phase eutectics of Na to stay in sand particle and lead to a decrease in the emission of heavy metals. The system was operated at a low gas velocity that not only easily resulted in agglomeration/defluidization but also increased the emission concentration of heavy metals. Large particles (920 {mu}m), which have a poor fluidized quality, had the highest emission concentration. Small particles (645 {mu}m) were uniformly fluidized to enhance the fluidization quality and to decrease the emission concentration. Additionally, adding Ca did not decrease the heavy metal emission concentration, but maintained the fluidization during eutectic accumulation. The Ca prevented the sand bed from quickly achieving defluidization and prolonged the increased emission of heavy metals after defluidization. (author)

  15. Tar Production from Biomass Pyrolysis in a Fluidized Bed Reactor: A Novel Turbulent Multiphase Flow Formulation

    Science.gov (United States)

    Bellan, J.; Lathouwers, D.

    2000-01-01

    A novel multiphase flow model is presented for describing the pyrolysis of biomass in a 'bubbling' fluidized bed reactor. The mixture of biomass and sand in a gaseous flow is conceptualized as a particulate phase composed of two classes interacting with the carrier gaseous flow. The solid biomass is composed of three initial species: cellulose, hemicellulose and lignin. From each of these initial species, two new solid species originate during pyrolysis: an 'active' species and a char, thus totaling seven solid-biomass species. The gas phase is composed of the original carrier gas (steam), tar and gas; the last two species originate from the volumetric pyrolysis reaction. The conservation equations are derived from the Boltzmann equations through ensemble averaging. Stresses in the gaseous phase are the sum of the Newtonian and Reynolds (turbulent) contributions. The particulate phase stresses are the sum of collisional and Reynolds contributions. Heat transfer between phases, and heat transfer between classes in the particulate phase is modeled, the last resulting from collisions between sand and biomass. Closure of the equations must be performed by modeling the Reynolds stresses for both phases. The results of a simplified version (first step) of the model are presented.

  16. Fluidized-Bed Gasification of Plastic Waste, Wood, and Their Blends with Coal

    Directory of Open Access Journals (Sweden)

    Lucio Zaccariello

    2015-08-01

    Full Text Available The effect of fuel composition on gasification process performance was investigated by performing mass and energy balances on a pre-pilot scale bubbling fluidized bed reactor fed with mixtures of plastic waste, wood, and coal. The fuels containing plastic waste produced less H2, CO, and CO2 and more light hydrocarbons than the fuels including biomass. The lower heating value (LHV progressively increased from 5.1 to 7.9 MJ/Nm3 when the plastic waste fraction was moved from 0% to 100%. Higher carbonaceous fines production was associated with the fuel containing a large fraction of coal (60%, producing 87.5 g/kgFuel compared to only 1.0 g/kgFuel obtained during the gasification test with just plastic waste. Conversely, plastic waste gasification produced the highest tar yield, 161.9 g/kgFuel, while woody biomass generated only 13.4 g/kgFuel. Wood gasification showed a carbon conversion efficiency (CCE of 0.93, while the tests with two fuels containing coal showed lowest CCE values (0.78 and 0.70, respectively. Plastic waste and wood gasification presented similar cold gas efficiency (CGE values (0.75 and 0.76, respectively, while that obtained during the co-gasification tests varied from 0.53 to 0.73.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

  18. Experimental investigation of thermal conductivity coefficient and heat exchange between fluidized bed and inclined exchange surface

    Directory of Open Access Journals (Sweden)

    B. Stojanovic

    2009-06-01

    Full Text Available The paper presents experimental research of thermal conductivity coefficients of the siliceous sand bed fluidized by air and an experimental investigation of the particle size influence on the heat transfer coefficient between fluidized bed and inclined exchange surfaces. The measurements were performed for the specific fluidization velocity and sand particle diameters d p=0.3, 0.5, 0.9 mm. The industrial use of fluidized beds has been increasing rapidly in the past 20 years owing to their useful characteristics. One of the outstanding characteristics of a fluidized bed is that it tends to maintain a uniform temperature even with nonuniform heat release. On the basis of experimental research, the influence of the process's operational parameters on the obtained values of the bed's thermal conductivity has been analyzed. The results show direct dependence of thermal conductivity on the intensity of mixing, the degree of fluidization, and the size of particles. In the axial direction, the coefficients that have been treated have values a whole order higher than in the radial direction. Comparison of experimental research results with experimental results of other authors shows good agreement and the same tendency of thermal conductivity change. It is well known in the literature that the value of the heat transfer coefficient is the highest in the horizontal and the smallest in the vertical position of the heat exchange surface. Variation of heat transfer, depending on inclination angle is not examined in detail. The difference between the values of the relative heat transfer coefficient between vertical and horizontal heater position for all particle sizes reduces by approximately 15% with the increase of fluidization rate.

  19. Analyses of coal gasifier and circulating fluidized bed combustion equipment using data base

    Energy Technology Data Exchange (ETDEWEB)

    Furusawa, Takehiko

    1988-09-01

    The construction of a coal and energy data base and the technical examples using it, such as coal gasifier and fluidized bed combustion equipment, were introduced. Wide ranges of data were collected to construct data base from gasifiers of 30 years ago or older to data reported in 1988 and design data of gasifiers under planning. The quantitative backup for the developing problems inherent to each gas-solid contact process and the relations between cold gas efficiency and factors influencing the cold gas efficiency which are improved along with the progress of technical development can be obtained. In the analysis of the fluidized bed coal combustion, the relation between thermal output and equipment's height was estimated with the mean wall surface heat transfer coefficient as the parameter. Further, the performane of particle withdrawal equipment was found to influence the combustion efficiency in the circulating fluidized bed combustion. (4 figs, 3 tabs, 2 refs)

  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. Design and evaluation of fluidized bed heat recovery for diesel engine systems

    Science.gov (United States)

    Hamm, J. R.; Newby, R. A.; Vidt, E. J.; Lippert, T. E.

    1985-01-01

    The potential of utilizing fluidized bed heat exchangers in place of conventional counter-flow heat exchangers for heat recovery from adiabatic diesel engine exhaust gas streams was studied. Fluidized bed heat recovery systems were evaluated in three different heavy duty transport applications: (1) heavy duty diesel truck; (2) diesel locomotives; and (3) diesel marine pushboat. The three applications are characterized by differences in overall power output and annual utilization. For each application, the exhaust gas source is a turbocharged-adiabatic diesel core. Representative subposed exhaust gas heat utilization power cycles were selected for conceptual design efforts including design layouts and performance estimates for the fluidized bed heat recovery heat exchangers. The selected power cycles were: organic rankine with RC-1 working fluid, turbocompound power turbine with steam injection, and stirling engine. Fuel economy improvement predictions are used in conjunction with capital cost estimates and fuel price data to determine payback times for the various cases.

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

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

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

  3. Effect of Fluidized Bed Stirring on Drying Process of Adhesive Particles

    Directory of Open Access Journals (Sweden)

    P. Hoffman

    2017-04-01

    Full Text Available This paper presents an attempt to optimize fluidized bed drying of wet and adhesive particles (with an initial diameter of about 580 mm with the use of stirring, and discusses the influence of stirring on the total drying time. The goal was to demonstrate the positive effect of stirring a fluidized bed to the drying time, to find the optimal parameters (stirrer design, speed, and size. Experiments were conducted on a drying chamber in batch operation. The objective was to evaluate the effect of stirring on the total drying time. The drying chambers were 85 mm, 100 mm, and 140 mm in diameter. An optimal stirrer shape and speed were specified. Our arrangement of the fluidized bed resulted in a decrease in drying time by up to 40 %.

  4. 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.

  5. Modeling of structural effects in biomedical elements after titanium oxidation in fluidized bed

    Science.gov (United States)

    Jasiński, J.; Szota, M.; Mendzik, K.

    2010-06-01

    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.

  6. Experimental and CFD study on the hydrodynamic characters of dense liquid-solid fluidized bed

    Science.gov (United States)

    Liu, Guodong; Lu, Huilin; Wang, Peng; Tang, Si; Wang, Shuai

    2013-07-01

    In a recent study the bed expansion height and liquid phase velocity was measured for liquid-solid fluidized bed with 0.10 m in diameter and 1.037m in height. Liquid flow velocity measurements were performed using the ultrasonic technique. Measurements of the bed expansion height were conducted by a graph paper marked along the length of the column. The Eulerian-Eulerian framework was employed in the CFD simulation of liquid hydrodynamics and solid motion in liquid fluidized bed. The typical flow pattern of the liquid-solid fluidized bed was obtained in the present calculation, i.e., the core annular flow pattern and back mixing near the wall region. Different fluid-particle drag models, virtual mass force and lift force effects were studied in the simulation. Also, comparisons of different restitution coefficients for particle-particle collisions as well as particle-wall interactions have been carried out to study the effect of particle collisions on solid concentration distributions, and a comprehensive CFD methodology is proposed to simulate the hydrodynamics of liquid-solid fluidized bed. A good agreement was demonstrated between CFD simulation results and experimental findings.

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

    Science.gov (United States)

    Chen, Guang-Liang; Fan, Song-Hua; Li, Chun-Ling; Gu, Wei-Chao; Feng, Wen-Ran; Zhang, Gu-Ling; Wang, Jiu-Li; Latif, K.; Zhang, Shu-Gen; Wang, Zhen-Quan; Han, Er-Li; Fu, Ya-Bo; Yang, Si-Ze

    2005-08-01

    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.

  8. 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. (c) 2010 Elsevier Ltd. All rights reserved.

  9. 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.

  10. Hydrodynamics in a cold-model jetting fluidized-bed gasifier with a binary mixture

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, K.; Zhang, J.; Zhang, B. [University of Petroleum, Beijing (China)

    2004-12-01

    The average properties of binary system defined by Goossens and others are incorporated into an Eulerian-Eulerian Computational Fluid Dynamics (CFD) model for simulating the hydrodynamics in a cold model of jetting fluidized bed gasifiers. Some of the essential hydrodynamic parameters, including gas - and solid-velocity profiles, time-averaged voidage profiles, and jet penetration height, are investigated in this paper. These results show the CFD approach is an effective tool for predicting hydrodynamics in jetting fluidized beds with multi-component mixture. 15 refs., 6 figs., 3 tabs.

  11. Two-stage fluidized-bed/cyclonic agglomerating incinerator. Technology spotlight report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    The two-stage fluidized-bed/cyclonic agglomerating incinerator combines and improves upon the fluidized-bed, agglomeration/ incineration-technology and the cyclonic-combustion technology developed at Institute of Gas Technolgy (IGT) over many years. The result is a unique and extremely flexible incinerator for solid, liquid, and gaseous wastes. The system can operate over a wide range of conditions and has a destruction and removal efficiency (DRE) greater than 99.99%. Solid inorganic contaminants are contained within aglassy matrix, rendering them benign and suitable for disposal in an ordinary landfill.

  12. The fluidized bed reactor with a prepolymerization system and its influence on polymer physicochemical characteristics

    Directory of Open Access Journals (Sweden)

    Fernandes F.A.N.

    2003-01-01

    Full Text Available This work addresses the influence of a prepolymerization system on the behavior of the fluidized bed reactor used for polyethylene production. Its influence on the polymer's physicochemical characteristics and production was also studied. The results indicate that the use of prepolymerized catalyst particles results in milder temperatures in the fluidized bed reactor, thus avoiding the formation of hot spots, melting of the polymer particle and reactor shutdown. Productivity can be enhanced depending on the operational conditions used in the prepolymerization reactor.

  13. The evaluation of empty bed contact time on the biodegradation of pentachlorophenol using an anaerobic GAC fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, G.J.; Khodadoust, A.P.; Suidan, M.T. [Univ. of Cincinnati, OH (United States); Wagner, J.A. [CH2M Hill, Milwaukee, WI (United States); Brenner, R.C. [Environmental Protection Agency, Cincinnati, OH (United States)

    1994-12-31

    The objective of this research is to evaluate the effects of decreasing the empty-bed contact time (EBCT) on pentachlorophenol and its intermediates utilizing an anaerobic granular activated carbon (GAC) fluidized bed. The bioreactor A was fed an 100 mg/l influent concentration of PCP. EBCTs of 1.167 to 0.292 days for reactor A resulted in a PCP reduction greater than 99%. In addition, an equimolar conversion of PCP to monochlorophenol was observed.

  14. Challenges and Issues on the CFD Modeling of Fluidized Beds: A Review

    Directory of Open Access Journals (Sweden)

    Paola Lettieri

    2009-06-01

    Full Text Available We first describe the main approaches used to model fluidized suspensions. Focusing on the multifluid approach, we overview the principal averaging techniques that consent to turn granular systems into continua; in particular, we discuss volume, ensemble and time averages. We then use volume averages to derive the Eulerian equations of motion for fluidized suspensions of a finite number of monodisperse particle classes. We introduce the closure problem, and overview some widely adopted closure equations used to express the granular stress and the interaction forces between the phases, giving emphasis to the fluid-particle interaction force, in particular to the buoyancy and drag contributions. We conclude the work by discussing some published CFD simulations of mono and bidisperse fluidized beds, spanning different fluidization regimes and commenting on the insight that these studies provide.

  15. Hydrodynamic analysis of a three-fluidized bed reactor cold flow model for chemical looping hydrogen generation. Pressure characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Zhipeng; Xiang, Wenguo; Chen, Shiyi; Wang, Dong [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    Chemical looping hydrogen generation (CLHG) can produce pure hydrogen with inherent separation of CO{sub 2} from fossils fuel. The process involves a metal oxide, as an oxygen carrier, such as iron oxide. The CLHG system consists of three reactors: a fuel reactor (FR), a steam reactor (SR) and an air reactor (AR). In the FR, the fuel gases react with iron oxides (hematite Fe{sub 2}O{sub 3}, magnetite Fe{sub 3}O{sub 4}, wuestite FeO), generating reduced iron oxides (FeO or even Fe), and with full conversion of gaseous fuels, pure CO{sub 2} can be obtained after cooling the flue gas from the fuel reactor; in the SR, FeO and Fe reacts with steam to generate magnetite (Fe{sub 3}O{sub 4}) and H{sub 2}, the latter representing the final target product of the process; in the AR, the magnetite is oxidized back to hematite which is used in another cycle. A cold flow model of three-fluidized bed for CLHG corresponding to 50 KW hot units has been built. A major novelty of this facility is the compact fuel reactor, which integrates a bubble and a fast fluidized bed to avoid the incomplete conversion of the fuel gas caused by the thermodynamics equilibrium. In order to study the pressure characteristics and the solids concentration of the system, especially in the fuel reactor, the gas velocity of three reactors, gas flow of L-type value, total solids inventory (TSI) and the secondary air of fuel reactor were varied. Results show that the pressure and the solids concentration are strongly influenced by the fluidizing-gas velocity of three reactors. Moreover, the entrainment of the upper part of fuel reactor increases as the total solids inventory increases, and the operating range of the FR can be changed by introducing secondary air or increasing the total solids inventory.

  16. A new method to quantify fluidized bed agglomeration in the combustion of biomass fuels

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, M. [Umeaa Univ. (Sweden). Dept. of Chemistry

    1997-12-31

    The present licentiate thesis is a summary and discussion of four papers, dealing with the development, evaluation and use of a new method to quantify bed agglomeration tendencies for biomass fuels. An increased utilization of biomass related fuels has many environmental benefits, but also requires careful studies of potential new problems associated with these fuels such as bed agglomeration/defluidization during combustion and gasification in fluidized beds. From a thorough literature survey, no suitable methods to determine bed agglomeration tendencies of different fuels, fuel combinations or fuels with additives appeared to be available. It therefore seemed of considerable interest to develop a new method for the quantification of fluidized bed agglomeration tendencies for different fuels. A bench scale fluidized bed reactor (5 kW), specially designed to obtain a homogeneous isothermal bed temperature, is used. The method is based on controlled increase of the bed temperature by applying external heat to the primary air and to the bed section walls. The initial agglomeration temperature is determined by on- or off-line principal component analysis of the variations in measured bed temperatures and differential pressures. Samples of ash and bed material for evaluation of agglomeration mechanisms may also be collected throughout the operation. To determine potential effects of all the process related variables on the determined fuel specific bed agglomeration temperature, an extensive sensitivity analysis was performed according to a statistical experimental design. The results showed that the process variables had only relatively small effects on the agglomeration temperature, which could be determined to 899 deg C with a reproducibility of {+-} 5 deg C (STD). The inaccuracy was determined to be {+-} 30 deg C (STD). The method was also used to study the mechanism of both bed agglomeration using two biomass fuels and prevention of bed agglomeration by co

  17. Experimental studies on combustion of composite biomass pellets in fluidized bed.

    Science.gov (United States)

    Guo, Feihong; Zhong, Zhaoping

    2017-12-01

    This work presents studies on the combustion of Composite Biomass Pellets (CBPS) in fluidized bed using bauxite particles as the bed material. Prior to the combustion experiment, cold-flow characterization and thermogravimetric analysis are performed to investigate the effect of air velocity and combustion mechanism of CBPS. The cold-state test shows that CBPs and bauxite particles fluidize well in the fluidized bed. However, because of the presence of large CBPs, optimization of the fluidization velocity is rather challenging. CBPs can gather at the bottom of the fluidized bed at lower gas velocities. On the contrary, when the velocity is too high, they accumulate in the upper section of the fluidized bed. The suitable fluidization velocity for the system in this study was found to be between 1.5-2.0m/s. At the same time, it is found that the critical fluidization velocity and the pressure fluctuation of the two-component system increase with the increase of CBPs mass concentration. The thermogravimetric experiment verifies that the combustion of CBPs is a first-order reaction, and it is divided into three stages: (i) dehydration, (ii) release and combustion of the volatile and (iii) the coke combustion. The combustion of CBPs is mainly based on the stage of volatile combustion, and its activation energy is greater than that of char combustion. During the combustion test, CBPS are burned at a 10kg/h feed rate, while the excess air is varied from 25% to 100%. Temperatures of the bed and flue gas concentrations (O2, CO, SO2 and NO) are recorded. CBPs can be burnt stably, and the temperature of dense phase is maintained at 765-780°C. With the increase of the air velocity, the main combustion region has a tendency to move up. While the combustion is stable, O2 and CO2 concentrations are maintained at about 7%, and 12%, respectively. The concentration of SO2 in the flue gas after the initial stage of combustion is nearly zero. Furthermore, NO concentration is found to

  18. 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.

  19. Hydrodynamics of a dual fluidized-bed gasifier. Part 2: Simulation of solid circulation rate, pressure loop and stability

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, S.; Loeffler, G.; Bosch, K.; Hofbauer, H. [Vienna Univ. of Technology, Inst. of Chemical Engineering, Fuel Technology and Environmental Technology, Vienna (Austria)

    2003-09-01

    This paper focuses on the determination of the solids circulation of a CFB gasification system with a dual fluidized bed concept, and the distribution of the solid hold up under different fluidization conditions. A mathematical model of the riser was designed and implemented in a model of a dual fluidized bed system. This model contains routines for calculation of each section of the dual fluidized bed system. The behaviour of the system was analysed regarding changes in solid inventory and variations of geometry. A diagram is presented which allows an illustration of the influence of changes in the dual fluidized bed system configuration on the resulting stable operation points. Analysis concerning the effect of counter pressure on the combustion and gasification side confirms the role of the seal loop in stabilizing the operation of the gasification system. (Author)

  20. Alternating electric field fluidized bed disinfection performance with different types of granular activated carbon

    NARCIS (Netherlands)

    Racyte, J.; Yntema, D.R.; Kazlauskaite, L.; DuBois, A.; Bruning, H.; Rijnaarts, H.H.M.

    2014-01-01

    The removal of pathogens from effluents is important to promote the reuse of these water resources and safeguarding human health, especially in water scarce areas worldwide. Previously a proof-of-principle of a method for water disinfection consisting of fluidized bed electrodes (FBE) with RX3 EXTRA

  1. Multi-scale CFD simulation of hydrodynamics and cracking reactions in fixed fluidized bed reactors.

    Science.gov (United States)

    Zhang, Jin H; Wang, Zhen B; Zhao, Hui; Tian, Yuan Y; Shan, Hong H; Yang, Chao H

    Fixed fluidized bed reactor is widely used to evaluate the crackability of heavy oils and the activity of catalysts. To understand the hydrodynamics, reaction kinetics and thermodynamics in conventional and modified fixed fluidized bed reactors, the computational fluid dynamics method, energy-minimization multi-scale-based two-fluid model coupled with a six-lump kinetic model was used to investigate the gas-solid flow and cracking reactions. The gas mixing and particle volume fraction distributions, as well as product yields in the conventional and modified fixed fluidized bed reactors were analyzed. The residence time distribution model was utilized to obtain the parameters indicating the back-mixing degree, such as mean residence time and dimensionless variance of the gas. The results showed that the simulated product distribution is in reasonable agreement with the experimental data; the modified fixed fluidized bed reactor is closer to the ideal plug flow reactor, which can efficiently enhance the gas-solid mixing, reduce the gas back-mixing degree, and hence improve the reaction performance.

  2. Transient Catalytic Activity of Calcined Dolomitic Limestone in a Fluidized Bed during Gasification of Woody Biomass.

    Czech Academy of Sciences Publication Activity Database

    Pohořelý, Michael; Jeremiáš, Michal; Skoblia, S.; Beňo, Z.; Šyc, Michal; Svoboda, Karel

    2016-01-01

    Roč. 30, č. 5 (2016), s. 4065-4071 ISSN 0887-0624 R&D Projects: GA ČR GC14-09692J Institutional support: RVO:67985858 Keywords : fluidized- bed gasification * woody biomass * limestone Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.091, year: 2016

  3. 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...

  4. The Hydrodynamic Stability of a Fluid-Particle Flow: Instabilities in Gas-Fluidized Beds

    Science.gov (United States)

    Liu, Xue; Howley, Maureen A.; Johri, Jayati; Glasser, Benjamin J.

    2008-01-01

    A simplified model of an industrially relevant fluid-particle flow system is analyzed using linear stability theory. Instabilities of the uniform state of a fluidized bed are investigated in response to small flow perturbations. Students are expected to perform each step of the computational analysis, and physical insight into key mechanistic…

  5. Development program on pressurized fluidized-bed combustion. Annual report, July 1, 1974--June 30, 1975

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, G.J.; Cunningham, P.; Fischer, J.

    1975-07-01

    The feasibility of using fluidized-bed combustors in power and steam plants is being evaluated. The concept involves burning fuels such as coal in a fluidized bed of either a naturally occurring, calcium-containing limestone or dolomite or in a synthetically prepared calcium-containing stone. The calcium oxide in the stone reacts with the sulfur released during combustion to form calcium sulfate, which remains in the bed, thus decreasing the level of SO/sub 2/ in the flue gas. Levels of NO/sub x/ in the flue gas are also low. The effect of operating variables and type of stone on the levels of SO/sub 2/ and NO/sub x/ is being determined. Behavior of trace elements during combustion has been preliminarily evaluated. The properties of a fluidized bed at minimum fluidization at different temperatures and pressures have been determined. The CaSO/sub 4/ produced in the combustion process is regenerated to CaO for reuse in the combustor by reductive decomposition at 1095/sup 0/C (2000/sup 0/F). The effects of operating variables on sulfur release during regeneration are being evaluated. Another regeneration process, solid-solid reaction of CaSO/sub 4/ with CaS, is also being investigated. Fundamental investigations of the kinetics of sulfation and regeneration reactions for the natural and synthetic stones are continuing. A model for the sulfation reaction is presented. The status of the new combustor andancillary regenerator equipment is discussed. (auth)

  6. Devolatilization and ignition of coal particles in a two-dimensional fluidized bed

    NARCIS (Netherlands)

    Prins, W.; Siemons, R.; van Swaaij, Willibrordus Petrus Maria

    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,

  7. Effect of temperature in fluidized bed fast pyrolysis of biomass: oil quality assessment in test units

    NARCIS (Netherlands)

    Westerhof, Roel Johannes Maria; Brilman, Derk Willem Frederik; van Swaaij, Willibrordus Petrus Maria; Kersten, Sascha 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. The influence of particle residence time distribution on the reactivity in fluidized bed reactors

    NARCIS (Netherlands)

    Heesink, Albertus B.M.; Klaus, J.; van Swaaij, Willibrordus Petrus Maria

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Fee, D.C.; Wilson, W.I.; Shearer, J.A.; Smith, G.W.; Lenc, J.F.; Fan, L.S.; Myles, K.M.; Johnson, I.

    1980-09-01

    The United States Government has embarked on an ambitious program to develop and commercialize technologies to efficiently extract energy from coal in an environmentally acceptable manner. One of the more promising new technologies for steam and power generation is the fluidized-bed combustion of coal. In this process, coal is burned in a fluidized bed composed mainly of calcined limestone sorbent. The calcium oxide reacts chemically to capture the sulfur dioxide formed during the combustion and to maintain the stack gas sulfur emissions at acceptable levels. The spent sulfur sorbent, containing calcium sulfate, is a dry solid that can be disposed of along with coal ash or potentially used. Other major advantages of fluidized-bed combustion are the reduction in nitrogen oxide emissions because of the relatively low combustion temperatures, the capability of burning wide varieties of fuel, the high carbon combustion efficiencies, and the high heat-transfer coefficients. A key to the widespread commercialization of fluidized-bed technology is the ability to accurately predict the amount of sulfur that will be captured by a given sorbent. This handbook meets this need by providing a simple, yet reliable, user-oriented methodology (the ANL method) that allows performance of a sorbent to be predicted. The methodology is based on only three essential sorbent parameters, each of which can be readily obtained from standardized laboratory tests. These standard tests and the subsequent method of data reduction are described in detail.

  10. Study and modelling of a reactional tube bundle heated by a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Collantes Hernandez, M.A.

    1993-07-01

    Fluidized beds exhibit two important characteristics for the heating of a reactional tube bundle: homogeneous temperature within all the fluidized bed and high heat transfer coefficient with the immersed surfaces. One of the key points for their modeling is the knowledge of the vertical and horizontal thermal conductivities and the heat transfer coefficient at the wall or with the tubes of the reactor. As thermal diffusivity data about large fluidized beds are not available in the literature, we have built a large size pilot unit (0.6 m x 1.1 m x 2.8 m) to determine these values under the conditions of a catalytic treatment of petroleum products. The measure of local temperatures and the use of a two-dimensional diffusion model have permitted us to determine thermal conductivities as a function of several parameters: fluidization velocity, height of the bed, nature and granulometry of solids and geometry of the tube bundle. On the basis of the collected experimental data, the case of a petrochemical unit has been studied. A mathematical code was developed, which permitted us to acquire the data concerning the progress of the reaction in the tubes and it also allowed us to analyse the influence of size and density of the tube bundles on the conversion. (author). 72 refs., 90 figs., 15 tabs.

  11. Fluidized bed combustion of a dry sludge-derived fuel at Los Angeles

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, F.M.; Huang, R.T.; Sizemore, H.M.

    1985-01-01

    A fluidized-bed/energy recovery system, scheduled for a 1985 startup, is designed to incinerate 265 dry tons of sludge per day and meet extremely stringent Los Angeles air pollution standards. Prior to combustion, the wet sludge cake is dried in a Carver Greenfield system from 20% to 99% solids.

  12. A review of oxy-fuel combustion in fluidized bed reactors

    CSIR Research Space (South Africa)

    Mathekga, HI

    2016-06-01

    Full Text Available JOURNAL OF ENERGY RESEARCH Int. J. Energy Res. (2016) Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/er.3486 A review of oxy-fuel combustion in fluidized bed reactors H. I. Mathekga, B. O. Oboirien*,† and B. C...

  13. Development of a bench-scale fluidized bed combustor (FBC) for ...

    African Journals Online (AJOL)

    coconut shell) using the relevant ASTM guidelines. For coal combustion, the characteristic quantities measured from the bench-scale fluidized bed combustion include a mean NOx emission of 455.35, 376.69, 323.35 and 277.35 ppm for a ...

  14. 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.

  15. 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…

  16. Safe design and operation of fluidized-bed reactors: Choice between reactor models

    NARCIS (Netherlands)

    Westerink, E.J.; Westerterp, K.R.

    1990-01-01

    For three different catalytic fluidized bed reactor models, two models presented by Werther and a model presented by van Deemter, the region of safe and unique operation for a chosen reaction system was investigated. Three reaction systems were used: the oxidation of benzene to maleic anhydride, the

  17. Building population balance model for fluidized bed melt granulation: lessons from kinetic theory of granular flow

    NARCIS (Netherlands)

    Tan, H.S.; Goldschmidt, M.J.V.; Boerefijn, R.; Hounslow, M.J.; Salman, A.; Kuipers, J.A.M.

    2004-01-01

    The purpose of this paper is to develop a theoretically sound basis for the equi-partition of kinetic energy (EKE) kernel recently developed by our group to describe the evolution of granule size distributions in fluidized bed granulation. The approach taken is to show first by distinct element

  18. Fast pyrolysis of biomass in a fluidized bed reactor: in-situ filtering of the vapors

    NARCIS (Netherlands)

    Hoekstra, E.; Hogendoorn, Kees; Wang, X.; Westerhof, Roel Johannes Maria; Kersten, Sascha R.A.; van Swaaij, Willibrordus Petrus Maria; Groeneveld, M.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

  19. Use of domestic low-grade fuels by combustion in fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Vuletic, V.; Ristic, M.

    1983-01-01

    The use of low-grade of coals with high sulphur and ash contents and low ash fusibility is difficult in conventional plant. The advantages of fluidized bed combustion for the utilization of such coals are described, and the possible application of this technology in Yugoslavia is examined.

  20. Neural networks for prediction and control of chaotic fluidized bed hydrodynamics : A first step

    NARCIS (Netherlands)

    Bakker, R; De Korte, RJ; Schouten, JC; Van den Bleek, CM; Takens, F

    A neural-network-based model that has learnt the chaotic hydrodynamics of a fluidized bed reactor is presented. The network is trained on measured electrical capacitance tomography data. A training algorithm is used that does not only minimize the short-term prediction error but also the information

  1. Process and device for spent catalyst regeneration with thermal exchange in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Pontier, R.; Hoffmann, F.

    1990-01-12

    Continuous regeneration of a spent catalyst by combustion of coke deposited during hydrocarbon conversion. The catalyst is introduced in a first regeneration reactor in presence of oxygen, partly regenerated catalyst is sent in a second regeneration zone at a temperature equal or higher. The catalyst is cooled and introduced in the first regeneration zone near the dense fluidized bed.

  2. Bed agglomeration in fluidized combustor fueled by wood and rice straw blends

    DEFF Research Database (Denmark)

    Thy, Peter; Jenkins, Brian; Williams, R.B.

    2010-01-01

    Abstract Petrographic techniques have been used to examine bed materials from fluidized bed combustion experiments that utilized wood and rice straw fuel blends. The experiments were conducted using a laboratory-scale combustor with mullite sand beds, firing temperatures of 840 to 1030 °C, and run...... particle surfaces by accumulation of liquid droplets preferentially in areas sheltered from turbulence and mechanical interaction. The composition of the film suggests melting of locally accumulated dust or aerosol mixture of ash particles and mullite. The film only locally enlarged bed particles. Large...... straw ash particles appear to have mostly been passively incorporated into the adhesive melt without melting or reaction....

  3. Improving the action of sulfur sorbents in the fluidized-bed combustion of coal

    Energy Technology Data Exchange (ETDEWEB)

    Schmal, D.

    1985-01-01

    As part of an investigation of the fluidised-bed combustion of coal and its environmental aspects, a study of the sorption of SO/sub 2/ as a combustion product has been undertaken. Special attention is being paid to the reactivation of fluidised-bed ash by treatment with water or water vapour, followed by heating to fluidised-bed temperatures. A laboratory research programme was carried out on the sulphation and reactivation of sorbents on their own, and of sorbent-containing ashes from a 4MW atmospheric fluidized-bed combustor. The experiments show that reactivation can be a versatile method for improving the efficiency of the sorbents.

  4. Heat recovery from Diesel exhausts by means of a fluidized bed heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Carlomagno, G.M.; Festa, R.; Massimilla, L.

    1983-01-01

    A fluidized bed heat exchanger, equipped with a specially designed manifold gas distributor, is conveniently used to recover heat from exhausts of a 60 kW Diesel engine. The sensitivity of the bed to tube heat transfer coefficient to soot fouling and the sensitivity of the exchanger efficiency to variations of such coefficients are analyzed. Procedures for in-operation tube defouling are described.

  5. Reaction engineering simulations of oxidative coupling of methane in a circulating fluidized-bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Pannek, U.; Mleczko, L. [Bochum Univ. (Germany). Lehrstuhl fuer Technische Chemie

    1998-10-01

    Oxidative coupling of methane in a circulating fluidized-bed reactor was investigated by means of reaction engineering modeling and simulations. A model of the reactor that combines comprehensive kinetics of the OCM and a model for the description of the bed hydrodynamics was developed and applied to predict the reactor performance. The important goal of the simulations was a better understanding of the effect of the hydrodynamic conditions in the riser reactor on the reaction pathway and the product distribution. (orig.)

  6. Co-Fuelling of Peat with Meat and Bone Meal in a Pilot Scale Bubbling Bed Reactor

    Directory of Open Access Journals (Sweden)

    Markku Orjala

    2010-07-01

    Full Text Available Co-combustion performance trials of Meat and Bone Meal (MBM and peat were conducted using a bubbling fluidized bed (BFB reactor. In the combustion performance trials the effects of the co-combustion of MBM and peat on flue gas emissions, bed fluidization, ash agglomeration tendency in the bed and the composition and quality of the ash were studied. MBM was mixed with peat at 6 levels between 15% and 100%. Emissions were predominantly below regulatory limits. CO concentrations in the flue gas only exceeded the 100 mg/m3 limit upon combustion of pure MBM. SO2 emissions were found to be over the limit of 50 mg/m3, while in all trials NOx emissions were below the limit of 300 mg/m3. The HCl content of the flue gases was found to vary near the limit of 30 mg/m3. VOCs however were within their limits. The problem of bed agglomeration was avoided when the bed temperature was about 850 °C and only 20% MBM was co-combusted. This study indicates that a pilot scale BFB reactor can, under optimum conditions, be operated within emission limits when MBM is used as a co-fuel with peat. This can provide a basis for further scale-up development work in industrial scale BFB applications.

  7. Co-Fuelling of peat with meat and bone meal in a pilot scale bubbling bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    McDonnell, K.; Cummins, E. J.; Fagan, C. C. [Biosystems Engineering, Bioresources Research Centre, UCD School of Agriculture, Food Science and Veterinary Medicine, Belfield, University College Dublin, Dublin 4 (Iran, Islamic Republic of); Orjala, M. [VTT Bioenergy, Koivurannantie, P.O. Box 1603, FIN- 40101 Jyvaeskylae (Finland)

    2010-07-15

    Co-combustion performance trials of Meat and Bone Meal (MBM) and peat were conducted using a bubbling fluidized bed (BFB) reactor. In the combustion performance trials the effects of the co-combustion of MBM and peat on flue gas emissions, bed fluidization, ash agglomeration tendency in the bed and the composition and quality of the ash were studied. MBM was mixed with peat at 6 levels between 15% and 100%. Emissions were predominantly below regulatory limits. CO concentrations in the flue gas only exceeded the 100 mg/m{sup 3} limit upon combustion of pure MBM. SO{sub 2} emissions were found to be over the limit of 50 mg/m{sup 3}, while in all trials NO{sub x} emissions were below the limit of 300 mg/m{sup 3}. The HCl content of the flue gases was found to vary near the limit of 30 mg/m{sup 3}. VOCs however were within their limits. The problem of bed agglomeration was avoided when the bed temperature was about 850 {sup o}C and only 20% MBM was co-combusted. This study indicates that a pilot scale BFB reactor can, under optimum conditions, be operated within emission limits when MBM is used as a co-fuel with peat. This can provide a basis for further scale-up development work in industrial scale BFB applications. (authors)

  8. Cold flow model investigations of the countercurrent flow of a dual circulating fluidized bed gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Johannes C.; Proell, Tobias; Kitzler, Hannes; Pfeifer, Christoph; Hofbauer, Hermann [Vienna University of Technology, Institute of Chemical Engineering, Vienna (Austria)

    2012-09-15

    A novel fluidized bed gasification concept with enhanced gas-particle interaction combining two circulating fluidized bed reactors is proposed. Cold flow model results show the feasibility of the concept with regard to fluid dynamics. The aim of the design is to generate a nitrogen (N{sub 2}) free product gas with low tars and fines contents. Therefore, the system is divided into an air/combustion and a fuel/gasification reactor. Two gas streams are obtained separately. The two reactors are interconnected via loop seals to assure the global circulation of bed material and to avoid gas leakages from one reactor to the other. The global circulation rate is driven by the gas velocity in the air/combustion reactor. Furthermore, the fuel/gasification reactor itself is a circulating fluidized bed with the special characteristic of almost countercurrent flow conditions for the gas phase and bed material particles. By simple geometrical modifications, it is possible to achieve well-mixed flow conditions in the fuel/gasification reactor along the full height. The gas velocity and the geometrical properties in the fuel/gasification reactor are chosen in such a way that the entrainment of coarse particles is low at the top. Due to the dispersed downward movement of the bed material particles and the feedstock input at defined locations of the fuel/gasification reactor, no volatiles are produced in the upper regions and the problems of insufficient gas phase conversion and high tar contents are avoided. (orig.)

  9. Thermo-hydrodynamic design of fluidized bed combustors estimating metal wastage

    CERN Document Server

    Lyczkowski, Robert W; Bouillard, Jacques X; Folga, Stephen M

    2012-01-01

    Thermo-Hydrodynamic Design of Fluidized Bed Combustors: Estimating Metal Wastage is a unique volume that finds that the most sensitive parameters affecting metal wastage are superficial fluidizing velocity, particle diameter, and particle sphericity.  Gross consistencies between disparate data sources using different techniques were found when the erosion rates are compared on the same basis using the concept of renormalization.  The simplified mechanistic models and correlations, when validated, can be used to renormalize any experimental data so they can be compared on a consistent basis using a master equation.

  10. 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.

  11. Simultaneous removal of multi-pollutants in an intimate integrated flocculation-adsorption fluidized bed.

    Science.gov (United States)

    Zhou, Dandan; Xu, Zhengxue; Wang, Yao; Wang, Jun; Hou, Dianxun; Dong, Shuangshi

    2015-03-01

    A novel intimate integrated flocculation-adsorption fluidized bed (IFAFB) was designed based on the hydraulic classification theory, and the operation, performance, characterization, and mechanisms of the novel process were developed. In this system, 150 mg · L(-1) kaolin clay and 100 mg · L(-1) phenol were used to simulate multi-pollutants in synthetic influent; resin beads and silica beads were the solid phases for the fluidized flocculator, and polymer aluminum chloride (PAC) and granular activated carbon were the flocculant and the adsorbent, respectively. The results showed that the Euler numeral was the most suitable dynamic parameter for flocculation in the fluidized bed when compared with the velocity gradient (G), Reynolds number (Re), and GRe (-1/2) . Additionally, the adsorption capacities of the fluidized regime were 8.77 and 24.70 mg · g(-1) greater than those of the fixed regime at superficial velocities of 6 and 8 mm · s(-1), respectively. In the IFAFB, the removal efficiencies of kaolin clay and phenol in the IFAFB reached 95 and 80 % simultaneously at total initial bed height of 35 mm. Flocs size, fractal dimension, and scanning electron microscopy (SEM) confirmed that the relationship of flocculation and adsorption in the IFAFB was mutually beneficial. Adsorption favored continuous growth of flocs and protected flocs from breakage, while flocculation removed fine particles as the first stage to prevent the adsorption of kaolin clay.

  12. Ash problem at wood fired fluidized bed plants; Askproblem vid skogsbraensleeldning i fluidbaedd

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, Soeren; Nystroem, Olle; Axby, Fredrik [Sycon Energikonsult AB, Malmoe (Sweden); Andersson, Christer; Kling, Aasa [Vattenfall Utveckling AB, Aelvkarleby (Sweden)

    2001-03-01

    Several ash related problems occurs during conversion from fossil fuels to bio fuels. The most frequent and expensive problem is agglomeration of bed material (in fluidized beds) and fouling on superheating surfaces. The last problem leads to corrosion problem and decreased transfer of heat. This project is the first part of a proposed project focussed on fluidized bed combustion (FB), because FB have become the dominating technology for combustion of biofuels. The project includes this first update of what has been done by different research institutes since 1997 and results of questionnaire on operating problems to owners of fluidized bed plants. A couple of pilot studies and different thermodynamical studies of bed agglomeration with biofuel combustion have been done during the latest years. There are no published reports where the results from agglomeration tests in pilot scale are verified in full scale plants. No project was found which deals with the fouling problem in the cyclone in a circulating fluidized bed. The knowledge of the mechanisms of deposits growth on heat surfaces is incomplete and more research has to be done of what can prevent the deposit growth. Experience from full scale plants shows that the deposits on heat surfaces grows during a period and after that it falls of the heating surface. There is little knowledge of which ash and flue gas conditions that affects these conditions for bio fuel. The operational experience with wood fuels in circulating fluidized beds is that the main problem with bed material is in the inlet and outlet of the cyclone. A total desulfonated of the bed occurs only when there has been other disturbances or because of operator mistakes. There are a number of things which seem to influence on the deposit problems: (1) Boilers with long residence time have less problem than boilers with short residence time. (2) Fuel size. No plant owner have continuos analysis of the fuel size, but combustion with problem have a

  13. Macroscopic modelling of fluid dynamics in large-scale circulating fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Pallares, David; Johnsson, Filip [Department of Energy and Environment, Energy Conversion, Chalmers University of Technology, SE 412 96 Goeteborg (Sweden)

    2006-09-15

    Macroscopic (semi-empirical) models for fluid dynamics of circulating fluidized bed (CFB) units are presented, with emphasize on applications for conditions relevant to industrial units such as fluidized-bed combustors. In order to make a structured analysis of the models, the CFB unit is divided into 6 fluid dynamical zones, which have been shown to exhibit different fluid-dynamical behaviour (bottom bed, freeboard, exit zone, exit duct, cyclone and downcomer and particle seal). The paper summarizes the main basis and assumptions for each model together with major advantages and drawbacks. In addition, a practical example on how a selected set of these local models can be linked to an overall model of the fluid dynamics of the entire CFB loop is presented. It is shown that it is possible to reach good agreement between the overall model and experimental data from industrial units. (author)

  14. The effect of ash composition on gasification of poultry wastes in a fluidized bed reactor.

    Science.gov (United States)

    Di Gregorio, Fabrizio; Santoro, Donato; Arena, Umberto

    2014-04-01

    The effect of ash composition on the fluidized bed gasification behaviour of poultry wastes was investigated by operating a pre-pilot scale reactor with two batches of manure obtained from an industrial chicken farm. The experimental runs were carried out by keeping the fluidized bed velocity fixed (at 0.4m s(-1)) and by varying the equivalence ratio between 0.27 and 0.40, so obtaining bed temperature values between 700 and 800 °C. The performance of the gasification process was assessed by means of mass balances as well as material and feedstock energy analyses, and reported in terms of cold gas efficiency (CGE), specific energy production, low heating value of obtained syngas and yield of undesired by-products. The experimental results indicate the crucial role of ash amount and composition of the two poultry wastes. In particular, higher ash content (25.1% instead of 17.2%) and higher fractions of calcium, phosphorous and potassium (with an increase of 24, 30 and 28%, respectively) induce a dramatic reduction of all the process performance parameters: CGE reduces from 0.63 to 0.33 and the specific energy from 2.1 to 1.1 kWh kg(fuel)(-1). At the same time, the formation of alkali compounds and their behaviour inside the fluidized bed reactor determine an increase of feedstock energy losses, which is related to occurrence of sintering and bridging between bed particles.

  15. A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems.

    Directory of Open Access Journals (Sweden)

    Juan Lu

    Full Text Available 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.

  16. Sensitivity Analysis and Accuracy of a CFD-TFM Approach to Bubbling Bed Using Pressure Drop Fluctuations.

    Science.gov (United States)

    Tricomi, Leonardo; Melchiori, Tommaso; Chiaramonti, David; Boulet, Micaël; Lavoie, Jean Michel

    2017-01-01

    Based upon the two fluid model (TFM) theory, a CFD model was implemented to investigate a cold multiphase-fluidized bubbling bed reactor. The key variable used to characterize the fluid dynamic of the experimental system, and compare it to model predictions, was the time-pressure drop induced by the bubble motion across the bed. This time signal was then processed to obtain the power spectral density (PSD) distribution of pressure fluctuations. As an important aspect of this work, the effect of the sampling time scale on the empirical power spectral density (PSD) was investigated. A time scale of 40 s was found to be a good compromise ensuring both simulation performance and numerical validation consistency. The CFD model was first numerically verified by mesh refinement process, after what it was used to investigate the sensitivity with regards to minimum fluidization velocity (as a calibration point for drag law), restitution coefficient, and solid pressure term while assessing his accuracy in matching the empirical PSD. The 2D model provided a fair match with the empirical time-averaged pressure drop, the relating fluctuations amplitude, and the signal's energy computed as integral of the PSD. A 3D version of the TFM was also used and it improved the match with the empirical PSD in the very first part of the frequency spectrum.

  17. Sensitivity Analysis and Accuracy of a CFD-TFM Approach to Bubbling Bed Using Pressure Drop Fluctuations

    Directory of Open Access Journals (Sweden)

    Leonardo Tricomi

    2017-06-01

    Full Text Available Based upon the two fluid model (TFM theory, a CFD model was implemented to investigate a cold multiphase-fluidized bubbling bed reactor. The key variable used to characterize the fluid dynamic of the experimental system, and compare it to model predictions, was the time-pressure drop induced by the bubble motion across the bed. This time signal was then processed to obtain the power spectral density (PSD distribution of pressure fluctuations. As an important aspect of this work, the effect of the sampling time scale on the empirical power spectral density (PSD was investigated. A time scale of 40 s was found to be a good compromise ensuring both simulation performance and numerical validation consistency. The CFD model was first numerically verified by mesh refinement process, after what it was used to investigate the sensitivity with regards to minimum fluidization velocity (as a calibration point for drag law, restitution coefficient, and solid pressure term while assessing his accuracy in matching the empirical PSD. The 2D model provided a fair match with the empirical time-averaged pressure drop, the relating fluctuations amplitude, and the signal’s energy computed as integral of the PSD. A 3D version of the TFM was also used and it improved the match with the empirical PSD in the very first part of the frequency spectrum.

  18. Sensitivity Analysis and Accuracy of a CFD-TFM Approach to Bubbling Bed Using Pressure Drop Fluctuations

    Science.gov (United States)

    Tricomi, Leonardo; Melchiori, Tommaso; Chiaramonti, David; Boulet, Micaël; Lavoie, Jean Michel

    2017-01-01

    Based upon the two fluid model (TFM) theory, a CFD model was implemented to investigate a cold multiphase-fluidized bubbling bed reactor. The key variable used to characterize the fluid dynamic of the experimental system, and compare it to model predictions, was the time-pressure drop induced by the bubble motion across the bed. This time signal was then processed to obtain the power spectral density (PSD) distribution of pressure fluctuations. As an important aspect of this work, the effect of the sampling time scale on the empirical power spectral density (PSD) was investigated. A time scale of 40 s was found to be a good compromise ensuring both simulation performance and numerical validation consistency. The CFD model was first numerically verified by mesh refinement process, after what it was used to investigate the sensitivity with regards to minimum fluidization velocity (as a calibration point for drag law), restitution coefficient, and solid pressure term while assessing his accuracy in matching the empirical PSD. The 2D model provided a fair match with the empirical time-averaged pressure drop, the relating fluctuations amplitude, and the signal’s energy computed as integral of the PSD. A 3D version of the TFM was also used and it improved the match with the empirical PSD in the very first part of the frequency spectrum. PMID:28695119

  19. 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.)

  20. Gasification of high ash content coals with steam in a semibatch fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Schmal, M.; Monterio, J.L.F.; Toscani, M.

    1983-10-01

    This work reports a study on gasification of Brazilian mineral subbituminous coal with steam in a semibatch fluidized bed reactor. Several tests for the fluidization characteristics of mixtures of coal and ash were performed. Fluidization velocity was determined from the data of the minimum velocity, calculated at high temperatures and later tested. Experimental results show that flow conditions must be determined experimentally for high temperatures and pressures. The influence of temperature and pressure on product gases during the reaction and on the ratio CO/CO/sub 2/ were determined. The reaction rate is very sensitive to temperature variations between 850 and 1000 /sup 0/C. For pressures higher than 10 atm the effect of the pressure on reaction rate is negligible. The experimental results are well described by the unreacted core model above 850 /sup 0/C where the chemical reaction is the rate controlling step. The activation energy was found to be 39 kcal/mol.

  1. Defluidization in fluidized bed gasifiers using high-alkali content fuels

    DEFF Research Database (Denmark)

    Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk

    2016-01-01

    and calcium, which may form viscous melts that adhere on the surface of the colliding bed particles and bind them to form agglomerates. In this paper, studies were made to understand the behavior of inorganic elements (mainly K, Si and Ca) on agglomeration and de-fluidization of alkali rich bed...... samples,agglomeration could be attributed to viscous silicate melts formed from reaction of inorganic alkalineand alkali earth species with silica from the bed particles. A mathematical model that addresses the defluidization behavior of alkali-rich samples was developed based on the experiments performed...

  2. Development of a membrane-assisted fluidized bed reactor - 2 - Experimental demonstration and modeling for the partial oxidation of methanol

    NARCIS (Netherlands)

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

    2005-01-01

    A small laboratory-scale membrane-assisted fluidized bed reactor (MAFBR) was constructed in order to experimentally demonstrate the reactor concept for the partial oxidation of methanol to formaldehyde. Methanol conversion and product selectivities were measured at various overall fluidization

  3. 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.

  4. Highlights of studies on fluidized-bed combustion of coal, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Jonke, A.A.; Carls, E.L.; Vogel, G.J.; Johnson, I.

    1978-02-01

    The highlights of the fluidized-bed coal combustion program at Argonne National Laboratory are described. Studies of the regeneration of sulfated limestone were conducted using the Laboratory's process development unit. The effects of operational variables on the regeneration process were investigated. The conditions which lead to agglomeration of the partially sulfated limestone and coal in the regenerator, and therefore defluidization, were established. Cyclic sulfation-regeneration studies were made on Greer limestone, and the overall economic feasibility of regeneration was studied. Laboratory TGA measurements at high temperatures were used to predict the performance of several limestones at the high temperatures used in carbon burnup cells; a significant SO/sub 2/ reactivity was predicted. The mechanism of the process by which NaCl enhances the SO/sub 2/ reactivity of limestone was established. The effectiveness of various clay minerals, silica gel, and activated bauxite for the removal of gaseous alkali metal compounds from a hot gas stream was measured. The results of studies of the filtration efficiencies of granular-bed filters for the removal of dust from the flue gas generated with a pressurized fluidized-bed combustor are reported. Two commercial light-scattering particle analyzers were tested, using the flue gas from the PFBC. The status of the design of the Component Test and Integration Unit (CTIU) is described. The CTIU is a pressurized fluidized-bed coal combustion test rig (3 megawatts) designed to allow various combustor configurations to be easily assembled and tested.

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-02-01

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

  6. Improving the performance of the Y-12 fluidized bed contactors: Final report on investigations at the University of Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Daw, C.S.; Hawk, J.A. [Oak Ridge National Lab., TN (United States)

    1993-08-01

    Recent tests at The University of Tennessee in Knoxville (UT) have demonstrated improved fluidization performance in a mockup of the Oak Ridge Y-12 Plant fluidized bed with a modified gas distributor. Combining the modified distributor with the recently developed fluidization intensity module is expected to result in substantial operational improvements for the fluidized beds in Building 9212 at Y-12. Important additional benefits coming from the improved operation of the Y-12 fluidized beds will be a reduction in the consumption of reactant gases, a reduction in scrubber waste production, and a reduced need for manual cleaning of the particulate removal system. UT tests have also demonstrated that the tapered wall design traditionally used for the Y-12 fluidized beds does not provide a sufficient improvement in fluidization quality to justify the continued use of this design in place of a more conventional straight-wall configuration. The straight-wall design for replacement beds is expected to result in substantial equipment cost savings. Other operating scenarios that could potentially be used to reduce reactant gas consumption and scrubber waste production have also been considered. These scenarios are documented here for future reference.

  7. Fluidized beds and their application to hazardous wastes incineration. Lecho fluidizado y su aplicacion a la incineracion de residuos peligrosos

    Energy Technology Data Exchange (ETDEWEB)

    Mullen, J.F.; Franco, M.

    1993-01-01

    The fluidized bed combustion technology and its application to sludge and hazardous wastes incineration are analyzed. A review on specific advantages of this technology including those related to investment costs, operation and maintenance, as well as operation flexibility are given.

  8. 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

  9. Experiment Investigation of the Influencing Factors on Bed Agglomeration During Fluidized-Bed Gasification of Biomass Fuels

    Science.gov (United States)

    Chen, Y. Q.; Chen, H. P.; Yang, H. P.; Wang, X. H.; Zhang, S. H.

    With the depleting of fossil fuel and environmental polluting increasing, the utilization of biomass resources caught increasing concern. Biomass gasification in fluidized bed, as one promising technology, developed quickly. However, serious agglomeration was displayed as biomass ash reacted with bed material (silica sand) at higher temperature. It hindered the wide utilization of CFB gasifier. The objective ofthis work is to investigate the agglomeration behavior between biomass ash and silica sand, and catch the inherent mechanism. Firstly, the influence of ash compounds on the agglomeration behavior was analyzed with biomass ash and synthesis ash compounds addition in fixed bed as ash sample mixed with bed material evenly before every trial. The reaction temperature was set 850°C that is the operated temperature for many fluidized bed gasificated biomass fuels. Then the influence of reaction time was analyzed. The characteristics of the agglomerated silica sand particles were analyzed by the XRD. Finally, it was simulated with HSC computer mode based on thermodynamic equilibrium. It was observed that when the ratio of the biomass ash to the silica sand was above 0.2, the agglomeration was observed. With the increase of the reaction time, more silica sand particles agglomerated with the biomass ash. There are two kinds of silicate eutecticum investigated by the XRD. It is of great significance for the running ofCFB biomass gasifier and the development ofbiomass utilization technology.

  10. Multicell fluidized bed boiler design construction and test program. Quarterly progress status report, January--March 1979

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-07-01

    The objective of this program is to design, construct, and test a multicell fluidized-bed boiler as a pollution-free method of burning high-sulfur or highly corrosive coals without excessive maintenance problems. The fluidized-bed boiler will provide approximately 300,000 pounds of steam per hour. Steam pressure and temperature conditions were selected to meet requirements of the site at which the boiler was installed.

  11. KARAKTERISTIK FISIKOKIMIA PATI SAGU HASIL PENGERINGAN SECARA FLUIDISASI MENGGUNAKAN ALAT PENGERING CROSS FLOW FLUIDIZED BED BERTENAGA SURYA DAN BIOMASSA

    Directory of Open Access Journals (Sweden)

    Abadi Jading

    2012-04-01

    Full Text Available PHYSICOCHEMICAL CHARACTERISTICS OF SAGO STARCH OBTAINED FROM FLUIDIZED BED DRYING USING SOLAR AND BIOMASS POWERED CROSS FLOW FLUIDIZED BED DRYER. The research aim is to study the comparative quality of sago starch drying results using cross flow fluidized bed dryer powered by solar and biomass in conventional drying, particularly the chemical composition and physicochemical characteristics. This research was conducted through a drying phase of wet sago starch using a cross flow fluidized bed dryer, and drying in conventional as well as dried sago starch quality testing results are drying. The results of this study indicate that dry sago starch which has been drained by means of cross flow fluidized bed dryer has a chemical composition that does not vary much with starch which is dried by conventional drying, so that the dried sago starch produced by the dryer is very good. On the other hand the use of dryers is the more correct because the physicochemical properties of sago starch using a low drying temperature and drying time is short. Tujuan penelitian ini adalah mempelajari perbandingan kualitas pati sagu hasil pengeringan menggunakan alat pengering cross flow fluidized bed bertenaga surya dan biomassa dengan pengeringan secara konvensional, khususnya komposisi kimia dan karakteristik fisikokimia. Penelitian ini dilakukan melalui beberapa tahapan yaitu pengeringan pati sagu basah menggunakan alat pengering cross flow fluidized bed, pengeringan secara konvensional serta pengujian kualitas pati sagu kering hasil pengeringan. Hasil dari penelitian ini menunjukkan bahwa pati sagu kering yang telah dikeringkan dengan alat pengering cross flow fluidized bed memiliki komposisi kimia yang tidak berbeda jauh dengan pati yang dikeringkan dengan cara pengeringan secara konvensional, sehingga pati sagu kering yang dihasilkan oleh alat pengering tersebut sangat baik. Di sisi lain penggunaan alat pengering ini semakin memperbaiki sifat fisikokimia pati

  12. 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.

  13. 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

    particle, can be described using the continuum approach, the pore network modelling method and the shrinkage of the diameter of the wet core approach. As several granules dry at a drying rate dependent on the gas temperature, gas velocity, porosity, etc., the moisture content of a batch of granules......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...... granules is given. This review provides a basis for future mechanistic model development for the drying process of wet granules in pharmaceutical processes. It is intended for a broad audience with a varying level of knowledge on pharmaceutical processes and mathematical modelling. Mathematical models...

  14. 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.

  15. 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)

  16. 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.

  17. 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.

  18. THE ALUMINA-SILICATES IN STABILIZATION PROCESSES IN FLUIDIZED-BED ASH

    Directory of Open Access Journals (Sweden)

    IVANA PERNA

    2011-03-01

    Full Text Available Presented study of coal fluidized-bed ash solidification was accompanied with specific studies of alumino-silicates residues in ashes. The specific technology of fluid coal burning and its relatively low temperature combustion combines coal burning and decomposition of calcium carbonate added to the fluid layer in the main endeavor to capture all sulfur oxides. The burning temperature seems be decisive to the behavior of clayed residues and calcium carbonate decomposition in connection for the future solidification of fluidized bed ash. The calcareous substances in combination with alumino-silicate residues form solid bodies where silicates play decisive role of long-term stability and insolubility of obtained solids. The position of aluminum ions in clayed residues of burned coal were studied by MAS-NMR with attention on aluminum ion coordination to oxygen and formation of roentgen amorphous phase of poly-condensed calcium alumina-silicate.

  19. Improving the gas-solids contact efficiency in a fluidized bed of CO2 adsorbent fine particles.

    Science.gov (United States)

    Valverde, J M; Pontiga, F; Soria-Hoyo, C; Quintanilla, M A S; Moreno, H; Duran, F J; Espin, M J

    2011-09-07

    A modified CO(2) adsorbent is obtained by dry mixing of a Ca(OH)(2) fine powder as received with a commercial silica nanopowder. Silica nanoparticles form light agglomerates of size of the order of tens of microns, which are uniformly fluidizable. These agglomerates act as dispersants of the Ca(OH)(2) fine particles, which coat the nanoparticle agglomerates likely due to contact charging. Ca(OH)(2) particles (CO(2) adsorbent) are thus provided with a vehicle for uniform fluidization. In this way, the contact efficiency between the CO(2) adsorbent and CO(2) in the fluidized bed is greatly enhanced. Experimental results show that the improvement of Ca(OH)(2) fluidizability serves to enhance the carbonation reaction in the fluidized bed. This journal is © the Owner Societies 2011

  20. A new design method for fluidized bed conversion of largely heterogeneous binary fuels

    Directory of Open Access Journals (Sweden)

    Szentannai Pal

    2017-01-01

    Full Text Available Binary fuels of a fluidized bed combustor or gasifier are solids composed of two groups of particles. Their optimal handling in the same bed becomes rather difficult if their hydrodynamic properties differ by two orders of magnitude or more. Both of these fuel classes are directly fed into the reactor in most cases but the rather homogeneous fuel originally fed switches into a binary character inside the reactor in some others. A typical example of the latter case is the thermal utilization of rubber wastes. A novel design is proposed in the present paper by setting up a non-mixing, non-elutriated binary bed. Design criteria and procedure are formulated as well. One of the known calculation methods is proposed to be applied for assuring a segregated bed by means of choosing the bed components, geometry, and gas velocity conveniently. Cold model experiments are proposed to be applied for assuring no elutriation of the fine fuel particles and no sinking of the coarse fuel particles in the same time. A simple experiment is proposed for determining the common minimum fluidization velocity of the binary bed because known calculation methods can not be applied here.

  1. Iron ore reduction in a continuously operated multistage lab-scale fluidized bed reactor—Mathematical modeling and experimental results

    Science.gov (United States)

    Thurnhofer, A.; Schuster, S.; Löffler, G.; Habermann, A.; Winter, F.; Hofbauer, H.; Schenk, J. L.; Zirngast, J.

    2006-08-01

    Industrial-scale fluidized bed processes for iron ore reduction ( e.g., FIOR and FINMET) are operated by continuous feeding of ore, while laboratory tests are mostly performed under batchwise operation. The reduction behavior under continuous operation is influenced by both the residence time of the iron ore particles and the reduction kinetics, which is obtained by batch tests. In a mathematical model for such a process, the effect of both phenomena has to be considered. The residence time distribution of iron ore particles in a laboratory fluidized bed reactor was obtained by measuring the response of a step input and described by mathematical models similar to a continuously stirred tank reactor. In the same reactor, reduction tests with continuous feeding of iron ore were performed. Based on batch tests in a fluidized bed reactor, a mathematical model was developed to describe the kinetics of iron ore reduction under fluidized bed conditions. This kinetic model was combined with the fluidized bed reactor model to describe continuous iron ore reduction. In this detailed model, the change of gas composition while rising in the fluidized bed was considered. The degree of reduction and the gas conversion for reactors in series were calculated. The results obtained by the mathematical model were compared with experimental data from the laboratory-scale reactor.

  2. Modeling of structural effects in biomedical elements after titanium oxidation in fluidized bed

    OpenAIRE

    Mendzik K.; Szota M.; Jasiński J.

    2010-01-01

    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...

  3. Coal. Fluidized bed, a world record; Charbon. Lit fluidise: record mondial

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    In April 1996, the `Societe Provencale du Lit Fluidise`, a subsidiary of Electricite de France (EDF) has put into service in Gardanne, the most powerful circulating fluidized bed boiler in the world, producing 600 MWt; it was constructed by GEC Alsthom Stein Industrie, and will strongly reduce the SO{sub 2} emissions from the coal power plant of Gardanne, which use a highly sulfurous coal. New regulations concerning the French coal industry are also introduced

  4. Apparatus for high flux photocatalytic pollution control using a rotating fluidized bed reactor

    Science.gov (United States)

    Tabatabaie-Raissi, Ali; Muradov, Nazim Z.; Martin, Eric

    2003-06-24

    An apparatus based on optimizing photoprocess energetics by decoupling of the process energy efficiency from the DRE for target contaminants. The technique is applicable to both low- and high-flux photoreactor design and scale-up. An apparatus for high-flux photocatalytic pollution control is based on the implementation of multifunctional metal oxide aerogels and other media in conjunction with a novel rotating fluidized particle bed reactor.

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

    Science.gov (United States)

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

    2013-01-01

    The gasification of sewage sludge was carried out in a simple atmospheric fluidized bed gasifier. Flow and fuel feed rate were adjusted for experimentally obtaining an air mass : fuel mass ratio (A/F) of 0.2 gasification. This allowed improving the process heat transfer and, therefore, gasification efficiency. The heating value of the produced gas was 8.4 MJ/Nm, attaining a hot gas efficiency of 70% and a cold gas efficiency of 57%. PMID:24453863

  6. 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)

  7. Proceedings of the sixth international conference on fluidized bed combustion. Volume III. 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. Forty-five papers from Vol. III of the proceedings have been entered individually into EDB and ERA. Two papers had been entered previously from other sources. (LTN)

  8. A statistical experimental design to remove sulfate by crystallization in a fluidized-bed reactor

    OpenAIRE

    Mark Daniel G. de Luna; Rance, Diana Pearl M.; Luzvisminda M. Bellotindos; Lu, Ming-Chun

    2016-01-01

    This study used crystallization in a fluidized-bed reactor as an alternative technology to the conventional chemical precipitation to remove sulfate. The Box-Behnken Design was used to study the effects and interactions of seed dosage of synthetic gypsum, initial sulfate concentration and molar ratio of calcium to sulfate on conversion and removal of sulfate. The optimum conditions of conversion and removal of sulfate were determined and used to treat the simulated acid mine drainage (AMD) wa...

  9. Fluidized bed reactor for polyethylene production. The influence of polyethylene prepolymerization

    Directory of Open Access Journals (Sweden)

    F.A.N. Fernandes

    2000-06-01

    Full Text Available This work addresses the influence of the prepolymerization of the catalyst particle on the fluidized bed reactor for polyethylene production. The influence of prepolymerization on the temperature and concentration gradients throughout the reactor was studied. The results obtained through simulations confirm industrial observations of the advantages of prepolymerization and extend these observation, showing the viable operational conditions for different superficial gas velocities and gas feeding temperatures as a function of the degree of prepolymerization.

  10. Study of particle movement in conical fluidized beds using the tracer method

    Energy Technology Data Exchange (ETDEWEB)

    Penkalla, H. J.; Gyarmati, E.; Nickel, H.

    1976-01-15

    In the work reported here, a method is described which enables the path and speed of the particles during fluidization to be measured using a tracer particle technique. Using statistical methods, it is then possible to determine the path-time diagram, the rate of circulation of the particles, the transport capacity, the extent of mixing and the relative residence time of the particles in a given zone of the bed. Measurements were made at room temperature in a 3'' model fluidized bed as a first step in evaluating the feasibility of the test method. Criteria for the type of coating, the growth rate of the coatings and the coating potential of the coating as were correlated with the relative dwell time of the particles and the dwell-time spectrum of the coating gases in a given part of the bed. It was therefore necessary to know the streaming behavior of the fluidizing gas, and so such an analysis was first carried out.

  11. Analysis of fluidized bed granulation process using conventional and novel modeling techniques.

    Science.gov (United States)

    Petrović, Jelena; Chansanroj, Krisanin; Meier, Brigitte; Ibrić, Svetlana; Betz, Gabriele

    2011-10-09

    Various modeling techniques have been applied to analyze fluidized-bed granulation process. Influence of various input parameters (product, inlet and outlet air temperature, consumption of liquid-binder, granulation liquid-binder spray rate, spray pressure, drying time) on granulation output properties (granule flow rate, granule size determined using light scattering method and sieve analysis, granules Hausner ratio, porosity and residual moisture) has been assessed. Both conventional and novel modeling techniques were used, such as screening test, multiple regression analysis, self-organizing maps, artificial neural networks, decision trees and rule induction. Diverse testing of developed models (internal and external validation) has been discussed. Good correlation has been obtained between the predicted and the experimental data. It has been shown that nonlinear methods based on artificial intelligence, such as neural networks, are far better in generalization and prediction in comparison to conventional methods. Possibility of usage of SOMs, decision trees and rule induction technique to monitor and optimize fluidized-bed granulation process has also been demonstrated. Obtained findings can serve as guidance to implementation of modeling techniques in fluidized-bed granulation process understanding and control. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-07-01

    Second-Generation Pressurized Fluidized Bed Combustion (PFBC) plants provide a coal-fired, high-efficiency, combined-cycle system for the generation of electricity and steam. The plants use lime-based sorbents in PFB combustors to meet environmental air standards without back-end gas desulfurization equipment. The second-generation system is an improvement over earlier PFBC concepts because it can achieve gas temperatures of 2100[degrees]F and higher for improved cycle efficiency while maintaining the fluidized beds at 1600[degrees]F for enhanced sulfur capture and minimum alkali release. Second-generation PFBC systems are capable of supplying the electric and steam process needs of industrial plants. The basic second-generation system can be applied in different ways to meet a variety of process steam and electrical requirements. To evaluate the potential of these systems in the industrial market, conceptual designs have been developed for six second-generation PFBC plants. These plants cover a range of electrical outputs from 6.3 to 41.5 MWe and steam flows from 46,067 to 442,337 lb/h. Capital and operating costs have been estimated for these six plants and for equivalent (in size) conventional, coal-fired atmospheric fluidized bed combustion cogeneration plants. Economic analyses were conducted to compare the cost of steam for both the second-generation plants and the conventional plants.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-07-01

    Second-Generation Pressurized Fluidized Bed Combustion (PFBC) plants provide a coal-fired, high-efficiency, combined-cycle system for the generation of electricity and steam. The plants use lime-based sorbents in PFB combustors to meet environmental air standards without back-end gas desulfurization equipment. The second-generation system is an improvement over earlier PFBC concepts because it can achieve gas temperatures of 2100{degrees}F and higher for improved cycle efficiency while maintaining the fluidized beds at 1600{degrees}F for enhanced sulfur capture and minimum alkali release. Second-generation PFBC systems are capable of supplying the electric and steam process needs of industrial plants. The basic second-generation system can be applied in different ways to meet a variety of process steam and electrical requirements. To evaluate the potential of these systems in the industrial market, conceptual designs have been developed for six second-generation PFBC plants. These plants cover a range of electrical outputs from 6.3 to 41.5 MWe and steam flows from 46,067 to 442,337 lb/h. Capital and operating costs have been estimated for these six plants and for equivalent (in size) conventional, coal-fired atmospheric fluidized bed combustion cogeneration plants. Economic analyses were conducted to compare the cost of steam for both the second-generation plants and the conventional plants.

  14. Prediksi Potensi Pencemaran Pengolahan Sampah dengan Metode Gasifikasi Fluidized Bed (Studi Kasus: TPA Benowo, Surabaya

    Directory of Open Access Journals (Sweden)

    Lailatun Nikmah

    2013-03-01

    Full Text Available Sistem pengelolaan sampah di TPA Benowo masih bersistem open dumping dan belum memperhatikan dampak pencemaran terhadap lingkungan. Kuantitas sampah yang masuk ke TPA sebesar 461.705,782 ton pada tahun 2012. Kuantitas sampah diperkirakan meningkat sebanding dengan pertumbuhan penduduk, sehingga dibutuhkan skenario pengolahan sampah yang ramah lingkungan. Skenario pengolahan sampah yang akan dikaji adalah gasifikasi  fluidized bed. Potensi pencemaran gasifikasi  fluidized bed akan dikaji menggunakan metode Life Cycle Assessment (LCA dengan software SimaPro versi 7.1. Satu ton sampah pada studi ini ditentukan sebagai satu fungsi unit. Data input Life Cycle Inventory (LCI meliputi jumlah sampah yang masuk ke reaktor gasifikasi dan energi yang dibutuhkan pada proses gasifikasi berdasarkan pendekatan efisiensi reaktor gasifikasi. Penentuan nilai Life Cycle Impact Assesment (LCIA meliputi Global Warming Potential (GWP dan asidifikasi menggunakan metode Environmental Product Declarations (EPD 2008. Besar dampak dinyatakan dalam faktor emisi yang ekivalen. Kesimpulan pada penelitian ini menunjukkan bahwa skenario pengolahan sampah dengan metode gasifikasi fluidized bed memberikan dampak GWP sebesar 1067,8 kg CO2/fu pada fase start-up dan 875 kg CO2/fu pada fase energy recovery serta asidifikasi sebesar 5,93 kg SO2/fu pada fase start-up dan 4,81 kg SO2/fu pada fase energy recovery.

  15. Mass Loss of Coal Particles Burning in Fluidized Bed

    Science.gov (United States)

    Pełka, Piotr

    2017-06-01

    In this work many conclusions resulting from research carried out on the coal combustion process of the chosen coal type and its accompanying erosion in a two-phase flow of inert material have been presented. The purpose of this flow was to present a model of the conditions of the central and upper zone of the combustion chamber of the fluidized boiler. In the opinion of many authors (Basu, 1999; Chirone et al., 1991), the erosion process results from the contact of a fuel particle with particles of inert material that is responsible for generating fine fuel particles of less than 100 mm. If the particles are in the upper zone of the boiler where there is oxygen deficit, they can increase the loss of incomplete combustion substantially. The results of research do not confirm this common thesis, but rather indicate that the process of comminution that results from erosion under oxidative conditions contributes to the increase of substantial mass loss of a coal particle, however the increased mass loss of particle during combustion is first and foremost due to the whole process of removal of ash from the reactionary surface of a fuel particle. Nevertheless, in the conditions of oxygen deficit the comminution of particles as a result of the erosion process is negligible

  16. Diesel oil combustion in fluidized bed; Combustion de aceite diesel en lecho fluidizado

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Cazares, Mario [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1992-07-01

    The effect of the fluidized bed depth in the combustion in burning diesel oil in a fluidized bed, was analyzed. A self sustained combustion was achieved injecting the oil with an injector that utilized a principle similar to an automobile carburetor venturi. Three different depths were studied and it was found that the deeper the bed, the greater the combustion efficiency. Combustion efficiencies were attained from 82% for a 100mm bed depth, up to 96% for a 200mm bed depth. The diminution in the efficiency was mainly attributed to unburned hydrocarbons and to the carbon carried over, which was observed in the black smoke at the stack outlet. Other phenomena registered were the temperature gradient between the lower part of the bed and the upper part, caused by the fluidization velocity; additionally it was observed that the air employed for the oil injection (carbureting air) is the most important parameter to attain a complete combustion. [Espanol] Se analizo el efecto de la profundidad del lecho en la combustion al quemar aceite diesel en un lecho fluidizado experimental. Se logro combustion autosostenida inyectando el aceite con un inyector que utilizo un principio similar al venturi del carburador de automovil. Se estudiaron tres diferentes profundidades del lecho y se encontro que a mayor profundidad del lecho, mayor eficiencia de la combustion. Se lograron eficiencias de la combustion desde 82% para el lecho de 100 mm de profundidad hasta 96% para el de 200 mm. La disminucion de la eficiencia se atribuyo, principalmente, a los hidrocarburos no quemados y al carbon arrastrado, lo cual se observo en el humo negro a la salida de la chimenea. Otros fenomenos registrados fueron el gradiente de temperatura entre la parte baja del lecho y la parte superior causado por la velocidad de fluidizacion; ademas, se observo que el aire utilizado para inyectar el aceite (aire de carburacion) es el parametro mas importante para lograr una combustion completa.

  17. Gasification of Coal and PET in Fluidized Bed Reactor

    Czech Academy of Sciences Publication Activity Database

    Pohořelý, Michael; Vosecký, Martin; Kameníková, Petra; Punčochář, Miroslav; Skoblia, Sergej; Staf, M.; Vošta, J.; Koutský, B.; Svoboda, Karel

    2006-01-01

    Roč. 85, 17-18 (2006), s. 2458-2468 ISSN 0016-2361 R&D Projects: GA ČR(CZ) GA104/04/0829 Institutional research plan: CEZ:AV0Z40720504 Keywords : fludized bed * gasification * plastic waste Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.358, year: 2006

  18. Sorption Characteristics of Organic Powder Sorption Material in Fluidized Bed with a Cooling Pipe

    Science.gov (United States)

    Horibe, Akihiko; Husain, Syahrul; Inaba, Hideo; Haruki, Naoto

    The dynamic sorption characteristics of organic sorbent materials have been studied by using fluidized bed with a cooling pipe. The organic powder type sorbent made from a bridged complex of sodium polyacrylate which is one of the sorption polymers is adopted in this study. Sorption rate of water vapor and the variation of temperature in the sorbent bed with time were measured under various conditions. As a result, sorption ratio increases and the completion time for the sorption process decreases by using a cooling pipe. Furthermore, the non-dimensional correlation equations were obtained for water vapor mass transfer under sorption process in terms of relevant non-dimensional parameters.

  19. Basic tests of in-furnace desulfurization in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Fujima, Y.; Ichimura, S.; Ohshima, K.

    1986-01-01

    This paper reports a study of the relation between lime reactivity and the desulfurization efficiency achieved in a circulating fluidized bed equipped with lime injection. Theoretical calculations were made of the reaction between Ca and SO/sub 2/, based on the assumption that this reaction takes place in a dilute zone. The required reaction time for Ca particles was found to coincide closely with the residence time of particles in a dilute bed. The authors give an equation relating percentage desulfurization with the Ca particle circulation rate. 4 refs., 6 figs.

  20. Flow visualizing study of fluidized bed for incineration and/or coal combustion technology

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, Mamoru [Kansai Univ., Suita, Osaka (Japan). Faculty of Engineering

    1997-02-01

    A simulated fluidized-bed heat exchanger was visualized using a neutron radiography system. The void fraction distribution and its fluctuation were obtained by means of an image processing technique. On the basis of the processed image, the mechanism of a large particle movement and the flow pattern in the tube bank immersed in the bed were investigated. Observed flow pattern in the tube bank indicated an importance of the tube arrangement on the void fraction fluctuation and thus the heat transfer around tubes. (author)

  1. Mechanisms of formation and destruction of nitrogen oxides during polyamide incineration in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Hahnel, F.; Gadiou, R.; Prado, G. [Univ. de Haute Alsace, Mulhouse (France). Lab. de Gestion des Risques et Environnement

    1998-09-01

    In order to study the incineration of nitrogen-containing polymers, a fludized bed has been built. This paper reports the results for polyamide 6-6 incineration. The main nitrogen containing species have been identified, and the axial profiles of concentration of nitrogen oxides, HCN and NH3 have been measured. The main steps of decomposition of the polyamide were identified. We present an experimental investigation of the influence of operating parameters (temperature, excess air) on the formation and reduction of polymer combustion products. The yields of conversion of nitrogen to the different N-species have been calculated as a function of excess air in the fluidized bed. (orig.)

  2. Capture of SO2 by limestone in a 71 MWe pressurized fluidized bed boiler

    Directory of Open Access Journals (Sweden)

    Shimizu Tadaaki

    2003-01-01

    Full Text Available A 71 MWe pressurized fluidized bed coal combustor was operated. A wide variety of coals were burnt under fly ash recycle conditions. Limestone was fed to the combustor as bed material as well as sorbent. The emission of SO^ and limestone attrition rate were measured. A simple mathematical model of SO? capture by limestone with intermittent solid attrition was applied to the analysis of the present experimental results. Except for high sulfur fuel, the results of the present model agreed with the experimental results.

  3. Influence of operational conditions on biofilm specific activity of an anaerobic fluidized bed reactor.

    Science.gov (United States)

    García-Morales, J L; Romero, L I; Sales, D

    2003-01-01

    A key parameter in water and wastewater treatment technology is the biomass activity in terms of substrate removal ability. The effects of organic load rate and percentage of bed expansion on biofilm specific methanogenic activity were determined in an anaerobic fluidized bed reactor treating wine-distillery wastes in the thermophilic range (55 degrees C). The proposed activity tests are highly reproducible: an experiment with three identical tests has shown that the standard deviation with respect to the mean values is less than 3%. Specific tests are applied to measure the maximum methanogenic activities of the biomass carrier in lab-scale anaerobic biofilm reactors. These tests have been successfully applied for monitoring the support colonization process and the evolution of biofilm activity in reactors, anaerobic filter and fluidized bed, with different operating conditions. The results show a dependence between the percentage of bed expansion and the specific activity of methanogenic microbiote on biofilm. There is a relationship between the percentage of bed expansion, the sheer stress on the biofilm and the hydrodynamic conditions in the system. Initial biofilm detachment can be compensated with the increase of biomass and of its activity due to the reduction of the substrate diffusional limitations to the microorganism growth inside the support pores.

  4. Model development and validation: Co-combustion of residual char, gases and volatile fuels in the fast fluidized combustion chamber of a dual fluidized bed biomass gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Priyanka Kaushal; Tobias Proell; Hermann Hofbauer [Vienna University of Technology, Vienna (Austria). Institute of Chemical Engineering

    2007-12-15

    A one-dimensional steady state model has been developed for the combustion reactor of a dual fluidized bed biomass steam gasification system. The combustion reactor is operated as fast fluidized bed (riser) with staged air introduction (bottom, primary and secondary air). The main fuel i.e., residual biomass char (from the gasifier), is introduced together with the circulating bed material at the bottom of the riser. The riser is divided into two zones: bottom zone (modelled according to modified two phase theory) and upper zone (modelled with core-annulus approach). The model consists of sub-model for bed hydrodynamic, conversion and conservation. Biomass char is assumed to be a homogeneous matrix of C, H and O and is modelled as partially volatile fuel. The exit gas composition and the temperature profile predicted by the model are in good agreement with the measured value. 34 refs., 8 figs., 3 tabs.

  5. Assembly-Controlled Permeability of Layer-by-Layer Polymeric Microcapsules Using a Tapered Fluidized Bed.

    Science.gov (United States)

    Noi, Ka Fung; Roozmand, Ali; Björnmalm, Mattias; Richardson, Joseph J; Franks, George V; Caruso, Frank

    2015-12-23

    Nano- and microcapsules engineered through layer-by-layer (LbL) assembly are finding an increasingly large number of applications as catalysts, electrochemical biosensors, bioreactors, artificial cells and drug delivery vehicles. While centrifugation-based LbL assembly is the most common method for coating template particles and preparing capsules, it is a batch process and requires frequent intervention that renders the system challenging to automate and scale up. Here, we report the use of a tapered fluidized bed (TFB) for the preparation of multilayered polymer capsules. This is a significant improvement over our recent approach of fluidizing particles in cylindrical fluidized beds (CFB) for LbL assembly. We demonstrate that TFB is compatible with particles microcapsules demonstrate increased film thickness and roughness compared with those prepared using centrifugation-based LbL assembly. Furthermore, PMASH microcapsules exhibit lower swelling and permeability when prepared via TFB LbL assembly compared with centrifugation-based LbL assembly due to enhanced multilayer deposition, entanglement, and cross-linking. Therefore, polymeric capsules fabricated via TFB LbL assembly may be useful for encapsulation and retention of relatively low molecular weight (∼20 kDa) hydrophilic biomacromolecules to passively or responsively release the payload for drug delivery applications.

  6. 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.

  7. 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.

  8. Mechanistic modelling of fluidized bed drying processes of wet porous granules: a review.

    Science.gov (United States)

    Mortier, Séverine Thérèse F C; De Beer, Thomas; Gernaey, Krist V; Remon, Jean Paul; Vervaet, Chris; Nopens, Ingmar

    2011-10-01

    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 granules is given. This review provides a basis for future mechanistic model development for the drying process of wet granules in pharmaceutical processes. It is intended for a broad audience with a varying level of knowledge on pharmaceutical processes and mathematical modelling. Mathematical models are powerful tools to gain process insight and eventually develop well-controlled processes. The level of detail embedded in such a model depends on the goal of the model. Several models have therefore been proposed in the literature and are reviewed here. The drying behaviour of one single granule, a porous particle, can be described using the continuum approach, the pore network modelling method and the shrinkage of the diameter of the wet core approach. As several granules dry at a drying rate dependent on the gas temperature, gas velocity, porosity, etc., the moisture content of a batch of granules 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 depending on the geometry of the gas inlet, the gas velocity, characteristics of the particles, the dryer design, etc. Computational Fluid Dynamics (CFD) allows to model this behaviour. Moreover, turbulence can be modelled using several approaches: Reynolds-averaged Navier-Stokes Equations (RANS) or Large 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

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

    Science.gov (United States)

    Krüger, B; Mrotzek, A; Wirtz, S

    2014-02-01

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

  10. A novel vortex-fluidized bed combustor with two combustion chambers for rice-husk fuel

    Directory of Open Access Journals (Sweden)

    Madhiyanon, T.

    2004-11-01

    Full Text Available A novel vortexing-fluidized bed combustor (VFBC using rice-husk as fuel was developed and presented. The combined characteristics of vortex combustion and fluidized bed combustion are the main features of the VFBC, which was designed to achieve high thermal capacity (MWth m-3, high thermal efficiency and low diameter to height ratio. The VFBC comprises a vertical cylinder chamber and a conical base, which provides a bed for incompletely combusted fuel. The overall dimensions are 1.10 m in height and 0.40 m in diameter. To evaluate combustor performance, the specific feed rate of fuel and mass flow rates of the primary, secondary, and tertiary air were varied independently of one another. The combustion appeared into two zones characterized by different combustion behaviors, i.e. 1 vortext combustion above the vortex ring and 2 fluidized bed combustion below the vortex ring. The fluidized bed zone has uniform temperature distributions across the cross-section of the combustor. The swirling of air above the vortex ringand the vortex ring itself played important roles in preventing the escape of combustion particulates. Bottomash appeared as fine black and grey particles of ash, which ranged in size from 200 to 600 µm. Fluidizationcould be initiated without the assistance of any inert material mixed into the bed. The experimental resultsindicated that thermal efficiency did not depend on the secondary or tertiary airflows, but was significantlyinfluenced by the excess air resulting from the combined total of the three airflows. The introduction of thetertiary airflow helped maintaining the temperature inside the combustor within acceptable levels. According to experimental conditions, i.e. a specific feed rate of 240 kg h-1m-3 and excess air (157%, it was found that the VFBC could achieve an exit gas temperature of 1060ºC, thermal efficiency of 95%, and thermal capacity of 0.91 MWth m-3. The amounts of CO2, CO, and O2 gases emitted were directly

  11. 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

  12. 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.

  13. Modeling of cleaning of dust emission’ in fluidized bed building aspiration’ collector

    Directory of Open Access Journals (Sweden)

    Koshkarev Sergey A.

    2017-01-01

    Full Text Available This article describes one of the modern way to reduce dust emissions of pollutions exhausting into the atmosphere at expanded clay aggregates and other similar building materials manufactures applying filtering fluidized granular particulate material bed’ separator with low degree of dust leakage out from one. There is presented quasi-diffusion model featuring of process of cleaning of industrial emissions of dust in devices of tray type with the fluidized and weighted bed. There considered case of variable coefficient of longitudinal hashing intermixing within trough tray type separator in this article. It was made attempt to get meanings value of leakage’ degree dust out from separator. It was obtain in an implicit form. It was obtained and announced some results of the carried-out analysis are intended to get high efficiency of dust removal set up installations to clean emissions of aspiration scheme of the air environmental protection in production of bulk dispersed materials building construction industry.

  14. Generation of hydrogen rich gas through fluidized bed gasification of biomass.

    Science.gov (United States)

    Karmakar, M K; Datta, A B

    2011-01-01

    The objective of this study was to investigate the process of generating hydrogen rich syngas through thermo chemical fluidized bed gasification of biomass. The experiments were performed in a laboratory scale externally heated biomass gasifier. Rice husk had been taken as a representative biomass and, steam had been used as the fluidizing and gasifying media. A thermodynamic equilibrium model was used to predict the gasification process. The work included the parametric study of process parameters such as reactor temperature and steam biomass ratio which generally influence the percentage of hydrogen content in the product gas. Steam had been used here to generate nitrogen free product gas and also to increase the hydrogen concentration in syngas with a medium range heating value of around 12 MJ/Nm3. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Preparation and Characterization of Inorganic PCM Microcapsules by Fluidized Bed Method.

    Science.gov (United States)

    Ushak, Svetlana; Cruz, M Judith; Cabeza, Luisa F; Grágeda, Mario

    2016-01-04

    The literature shows that inorganic phase change materials (PCM) have been very seldom microencapsulated, so this study aims to contribute to filling this research gap. Bischofite, a by-product from the non-metallic industry identified as having good potential to be used as inorganic PCM, was microencapsulated by means of a fluidized bed method with acrylic as polymer and chloroform as solvent, after compatibility studies of both several solvents and several polymers. The formation of bischofite and pure MgCl₂·6H₂O microcapsules was investigated and analyzed. Results showed an efficiency in microencapsulation of 95% could be achieved when using 2 min of fluidization time and 2 kg/h of atomization flow. The final microcapsules had excellent melting temperatures and enthalpy compared to the original PCM, 104.6 °C and 95 J/g for bischofite, and 95.3 and 118.3 for MgCl₂·6H₂O.

  16. Gasification of high ash content coals with steam in a semibatch fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Schmal, M.

    1983-10-01

    The work reports a study of gasification of a Brazilian subbituminous coal with steam in a semi-batch fluidized bed reactor. Several tests of the fluidization characteristics of mixtures of coal and ash were carried out. Experimental results show that flow conditions must be determined experimentally for high temperatures and pressures. The influences of temperature and pressure on product gases and on the CO/CO/sub 2/ ratio were determined. The reaction is very sensitive to temperature variations between 850 and 1000 C. For pressures above 10 atm, the effect of pressure on the reaction rate is negligible. The experimental results are well described by the uncreacted core model above 850 C where the chemical reaction is the rate-controlling step.

  17. Case study applications of venture analysis: fluidized bed. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mosle, R.

    1978-05-01

    In order to appraise the case for government intervention in the case of atmospheric fluid-bed combustion, Energy Resources Company and Rotan Mosle have developed a methodology containing four key elements. The first is an economic and environmental characterization of the new technology; the second, a survey of its prospective users and vendors; the third, a cost-benefit analysis of its prospective social benefits; and the fourth, an analytical model of its market penetration and the effects thereon of a basket of government incentives. Three major technical obstacles exist to continued AFBC development: feeding coal and limestone reliably to the boiler, tube erosion and corrosion, and developing boiler turndown capability. The review of the economic, environmental and technical attributes of the new technology has suggested that the preliminary venture can be selected with confidence as a commercial prospect capable of detailed evaluation from both private and public perspectives. The venture choice can therefore be considered firm: it will be the equipment required for the combustion of coal in atmospheric fluid beds as applied to industrial process steam in boilers of at least 83 Kpph capacity. The most effective demonstration of the potential of AFBC in the eyes of prospective industrial users is that provided by a project conducted by the private sector with minimal government direction. Unlike the ''experimental'' style of existing mixed public-private demonstration projects, the pressure to achieve reliability in more commercial applications would serve rapidly to reveal more clearly the potential of AFBC. The marketplace can be allowed to decide its fate thereafter. Once AFBC has been successfully demonstrated, the relative merits of AFBC and coal-FGD are best left to prospective users to evaluate.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-10-01

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

  19. 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

  20. H₂-rich syngas production by fluidized bed gasification of biomass and plastic fuel.

    Science.gov (United States)

    Ruoppolo, G; Ammendola, P; Chirone, R; Miccio, F

    2012-04-01

    This paper reports the results of gasification tests using a catalytic fluidized bed gasifier to obtain a H(2)-rich stream by feeding different pellets made of wood, biomass/plastic and olive husks to the gasifier. The effects of both the steam supply and an in-bed catalyst on gasifier performance have been investigated. In general, pelletization was an effective pre-treatment for improving the homogeneity of the fuel and the reliability of the feeding devices. The use of biomass/plastic pellets in a catalyst bed yielded good results in terms of the hydrogen concentration (up to 32%vol.), even if an increase in tar production and in the fine/carbon elutriation rate was observed in comparison with wood pellets. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Behavior of Alkali Metals and Ash in a Low-Temperature Circulating Fluidized Bed (LTCFB) Gasifier

    DEFF Research Database (Denmark)

    Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk

    2016-01-01

    and a minor fraction of Cl. Most Cl and S were released in gaseous form, with chlorine partly asmethyl chloride. The tar in the product gas from the LTCFB gasifier contained only negligible amounts of potassium and otherinorganic elements. The release of condensed ash species from the system was controlled......A low-temperature circulating fluidized bed system (LTCFB) gasifier allows for pyrolysis and gasification to occurat low temperatures, thereby improving the retention of alkali and other inorganic elements within the system and minimizingthe amount of ash species in the product gas. In addition......, the low reactor temperature ensures that high-alkali biomass fuels canbe used without risk of bed defluidization. This paper presents the first investigation of the fate of alkali metals and ash in lowtemperaturegasifiers. Measurements on bed material and product gas dust samples were made on a 100 k...

  2. Standpipe models for diagnostics and control of a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Ludlow, James C. [retired; Panday, Rupen [REM Engineering PLLC

    2013-01-01

    Two models for a Circulating Fluidized Bed (CFB) standpipe were formulated, implemented and validated to estimate critical CFB operational parameters. The first model continuously estimates standpipe bed height using incremental pressure measurements within the standpipe. The second model estimates variations in the void fraction along the standpipe using the Ergun equation in conjunction with the overall pressure drop across the bed, solids circulation rate and the standpipe aeration flows introduced at different locations of the pipe. The importance of different standpipe parameters obtained from these models is discussed in terms of successful operation of the overall CFB system. Finally, the applications of these models are shown in improving the solids circulation rate measurement and in calculating riser inventory.

  3. Hydrodynamics study on drying of pepper in swirling fluidized bed dryer (SFBD)

    Science.gov (United States)

    Syaif Haron, Nazrul; Hazri Zakaria, Jamal; Faizal Mohideen Batcha, Mohd

    2017-08-01

    Malaysia is one of the pepper producer with exports quantity reaching more than 90000 tonnes between 2010 until 2016. Drying of pepper is mandatory before their export and at present, pepper was dried by sun drying to reduce cost. This conventional drying method was time consuming and may take four days during rainy season, which retards the production of pepper. This paper proposes the swirling fluidized bed drying (SFBD) method, which was known to have high mixing ability and improved solid-gas contact to shorten the drying time of products. A lab scale SFBD system was constructed to carry out this study. Hydrodynamic study was conducted for three beds loadings of 1.0 kg, 1.4 kg at a drying temperature of 90°C. The SFBD has shown excellent potential to dry the pepper with a relatively short drying time compared to the conventional method. Batch drying for the bed loads studied only took 3 hours of drying time only. It was found that bed higher bed loading of wet pepper requires longer drying time due to higher amount of moisture content in the bed. Four distinct regimes of operation were found during drying in the SFBD and these regimes offer flexibility of operation. The total bed pressure drop was relatively low during drying.

  4. Caracterização de cinza obtida por combustão de casca de arroz em reator de leito fluidizado Characterization of ash from combustion of rice husk in a fluidized bed reactor

    Directory of Open Access Journals (Sweden)

    Juan Daniel Martínez Angel

    2009-01-01

    Full Text Available The rice husk combustion in a bubbling and atmospheric fluidized bed reactor was investigated. This paper presents the rice husk ash characterization employing the techniques of X-ray diffraction (XRD, X-ray fluorescence (XRF, and scanning electron microscopy (SEM among others. After combustion, a rice husk ash containing 93% amorphous silica and <3% unburned char was produced. Methods usually applied to fixed bed considering external sources of energy and high reaction times were employed. Thus, the potential of this type of reactors with respect to speed, continuity and self-sufficiency energy of the process was shown.

  5. Wall-to-bed mass transfer in three phase fluidized beds in the presence of angled disc promoter

    Science.gov (United States)

    Rohini Kumar, P.; Ashok Kumar, K.; Murty, M. S. N.; Ramesh, K. V.

    2017-10-01

    Mass transfer coefficient data were computed from measured limiting current values obtained at point electrodes fixed flush with the inner wall of an outer cylinder of three phase fluidized bed electrochemical reactor in the presence of an angled disc internal. Nitrogen was used as gas phase. Glass balls of different diameters were used as solid phase. The liquid phase was an electrolyte that belonged to the ferricyanide-ferrocyanide redox system. Enhancement in mass transfer coefficient obtained in the case of three-phase fluidized bed in the presence of angled disc internal was upto 14 fold in comparison with the homogeneous flow of electrolyte in plain pipe. The mass transfer coefficient data thus obtained were found to increase with increasing gas velocity, pitch and disc diameter. An increase in disc angle resulted in a decrease in the mass transfer coefficient. The influence of liquid velocity, promoter rod diameter and particle diameter on mass transfer coefficient was found to be insignificant. The entire mass transfer coefficient data obtained in the present study were subjected to regression analysis and useful correlation equation was obtained.

  6. Investigation of Anaerobic Fluidized Bed Reactor/ Aerobic Moving Bed Bio Reactor (AFBR/MMBR) System for Treatment of Currant Wastewater

    Science.gov (United States)

    JAFARI, Jalil; MESDAGHINIA, Alireza; NABIZADEH, Ramin; FARROKHI, Mehrdad; MAHVI, Amir Hossein

    2013-01-01

    Background: Anaerobic treatment methods are more suitable for the treatment of concentrated wastewater streams, offer lower operating costs, the production of usable biogas product. The aim of this study was to investigate the performance of an Anaerobic Fluidized Bed Reactor (AFBR)-Aerobic Moving Bed Bio Reactor (MBBR) in series arrangement to treat Currant wastewater. Methods: The bed materials of AFBR were cylindrical particles made of PVC with a diameter of 2–2.3 mm, particle density of 1250 kg/m3. The volume of all bed materials was 1.7 liter which expanded to 2.46 liters in fluidized situation. In MBBR, support media was composed of 1.5 liters Bee-Cell 2000 having porosity of 87% and specific surface area of 650m2/m3. Results: When system operated at 35 ºC, chemical oxygen demand (COD) removal efficiencies were achieved to 98% and 81.6% for organic loading rates (OLR) of 9.4 and 24.2 g COD/l.d, and hydraulic retention times (HRT) of 48 and 18 h, in average COD concentration feeding of 18.4 g/l, respectively. Conclusion: The contribution of AFBR in total COD removal efficiency at an organic loading rate (OLR) of 9.4 g COD/l.d was 95%, and gradually decreased to 76.5% in OLR of 24.2 g COD/l.d. Also with increasing in organic loading rate the contribution of aerobic reactor in removing COD gradually decreased. In this system, the anaerobic reactor played the most important role in the removal of COD, and the aerobic MBBR was actually needed to polish the anaerobic treated wastewater. PMID:26056640

  7. Combustion and emission characteristics of a swirling fluidized-bed combustor burning moisturized rice husk

    Energy Technology Data Exchange (ETDEWEB)

    Kuprianov, Vladimir I.; Chakritthakul, Songpol [School of Manufacturing Systems and Mechanical Engineering, Sirindhorn International Institute of Technology, Thammasat University, Pathum Thani 12121 (Thailand); Kaewklum, Rachadaporn [School of Manufacturing Systems and Mechanical Engineering, Sirindhorn International Institute of Technology, Thammasat University, Pathum Thani 12121 (Thailand); Department of Mechanical Engineering, Burapha University, Chonburi 20131 (Thailand); Sirisomboon, Kasama [Department of Mechanical Engineering, Silpakorn University, Nakhon Pathom 73000 (Thailand); Arromdee, Porametr [School of Manufacturing Systems and Mechanical Engineering, Sirindhorn International Institute of Technology, Thammasat University, Pathum Thani 12121 (Thailand); Department of Mechanical Engineering, Silpakorn University, Nakhon Pathom 73000 (Thailand)

    2010-09-15

    Burning of rice husk in a swirling fluidized-bed combustor (SFBC) was the focus of this experimental study. Swirl motion of a fluidized bed in this combustor was induced by an annular spiral distributor of primary air and also promoted by tangential injection of secondary air into the bed splash zone. ''As-received'' rice husk was moisturized with the aim to control NO emission from the combustor. The SFBC was tested at a constant fuel feed rate (of about 80 kg/h) for six fuel-moisture contents (from 8.4% to 35%). In each test series for the particular fuel quality, excess air was ranged from about 20% to 80%. Radial and axial profiles of temperature and gas concentrations (O{sub 2}, CO and NO) were plotted for different fuel options and operating conditions with the aim to study pollutants formation and reduction in different regions of the SFBC. With increasing the fuel-moisture content, the emission of NO from the combustor apparently reduced, while the emission of CO was adjusted at a quite low level due to the effects of secondary air. An effective least-cost control of both NO and CO emissions and high (over 99%) combustion efficiency are achievable when firing moisturized rice husk in this SFBC. (author)

  8. 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.

  9. Development program on pressurized fluidized-bed combustion. Annual report, July 1975--June 1976

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, G.J.; Johnson, I.; Cunningham, P.T.

    1976-07-01

    The feasibility of using fluidized-bed combustors in power and steam plants is being evaluated. The concept involves burning fuels such as coal in a fluidized bed of either a limestone (CaCO/sub 3/) or a synthetically prepared calcium-containing stone. The calcium reacts with the sulfur to form CaSO/sub 4/, which remains in the bed, thus decreasing the level of SO/sub 2/ in the flue gas. Levels of NO/sub x/ in the flue gas are low. In a separate step, the CaSO/sub 4/ is regenerated to CaO by reductive decomposition at Ca/sub solar/ 1100/sup 0/C for reuse in the combustor. Progress is reported on the following: the effect of regeneration operating variables on extent of regeneration and SO/sub 2/ concentration in the off-gas using coal as the source of reducing agent and of heat; the alternate combustion and regeneration behavior of stone; the rate and extent of sulfation of agents impregnated on Al/sub 2/O/sub 3/; the effect of variables on sorption and release of sulfur for CaO-impregnated stone; attrition resistance of stone; the kinetic and structural changes occurring during half-calcination of dolomite; the CaS-CaSO/sub 4/ regeneration reaction; and the volatility of trace elements when heating coal ash. Procurement and disposal of regenerated stone, minimum fluidization studies, modeling of a gas-solid combustion reaction and of the regeneration process, combustion studies using different sizes of coal and additive and also using lignite are reported.

  10. Performance analysis and pilot plant test results for the Komorany fluidized bed retrofit project

    Energy Technology Data Exchange (ETDEWEB)

    Snow, G.C. [POWER International, Inc., Coeur d`Alene, ID (United States)

    1995-12-01

    Detailed heat and mass balance calculations and emission performance projections are presented for an atmospheric fluidized bed boiler bottom retrofit at the 927 MWt (steam output) Komorany power station and district heating plant in the Czech Republic. Each of the ten existing boilers are traveling grate stoker units firing a local, low-rank brown coal. This fuel, considered to be representative of much of the coal deposits in Central Europe, is characterized by an average gross calorific value of 10.5 MJ/kg (4,530 Btu/lb), an average dry basis ash content of 47 %, and a maximum dry basis sulfur content of 1.8 % (3.4 % on a dry, ash free basis). The same fuel supply, together with limestone supplied from the region will be utilized in the retrofit fluidized bed boilers. The primary objectives of this retrofit program are, (1) reduce emissions to a level at or below the new Czech Clean Air Act, and (2) restore plant capacity to the original specification. As a result of the AFBC retrofit and plant upgrade, the particulate matter emissions will be reduced by over 98 percent, SO{sub 2} emissions will be reduced by 88 percent, and NO{sub x} emissions will be reduced by 38 percent compared to the present grate-fired configuration. The decrease in SO{sub 2} emissions resulting from the fluidized bed retrofit was initially predicted based on fuel sulfur content, including the distribution among organic, pyritic, and sulfate forms; the ash alkalinity; and the estimated limestone calcium utilization efficiency. The methodology and the results of this prediction were confirmed and extended by pilot scale combustion trials at a 1.0 MWt (fuel input), variable configuration test facility in France.

  11. Engineering Test Report Paint Waste Reduction Fluidized Bed Process Demonstration at Letterkenny Army Depot Chambersburg, Pennsylvania

    Science.gov (United States)

    1991-07-01

    1,400 to 1,600*F "and may sometimes reach 2,000’F. There Is a potential for burns due to human contact with the FBPS surfaces and metal processed in the...34ATMOSPHERIC EMMISSION SITE TEST PLAN AND QUALITY ASSURANCE PROJECT PLAN FOR FLUIDIZED.BED PAINT REMOVAL DEMONSTRATION TESTS, LETTERKENNY ARMY DEPOT...2,000 OF. There Is a potential for burns due to human contact with the FBPS surfaces and metal processed In the FBPS. The FBPS Is designed with Insulation

  12. Gasification of waste wood and bark in a dual fluidized bed steam gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Wilk, Veronika [Bioenergy2020+ GmbH, Guessing (Austria); Kitzler, Hannes; Koppatz, Stefan; Pfeifer, Christoph [Vienna University of Technology, Institute of Chemical Engineering, Vienna (Austria); Hofbauer, Hermann [Bioenergy2020+ GmbH, Guessing (Austria); Vienna University of Technology, Institute of Chemical Engineering, Vienna (Austria)

    2011-07-15

    Because of the limited resources of fossil fuels the efficient use of renewable energy is gaining importance. Renewable energy from biomass reduces CO{sub 2} emissions, which is a necessity to protect the global climate. In the dual fluidized bed steam gasifier, wood chips are converted to producer gas, which is further used for heat, power, and/or other product generation very successfully. This work presents alternative feedstocks for this process: biomass wastes, such as waste wood and bark. Waste wood and bark have been gasified successfully and results of these experiments in a pilot plant are presented in this paper. (orig.)

  13. Development of methanogenic consortia in fluidized-bed batches using sepiolite of different particle size.

    Science.gov (United States)

    Sánchez, J M; Rodríguez, F; Valle, L; Muñoz, M A; Moriñigo, M A; Borrego, J J

    1996-09-01

    The addition of support materials, such as sepiolite, to fluidized-bed anaerobic digesters enhances the methane production by increasing the colonization by syntrophic microbiota. However, the efficiency in the methanogenesis depends on the particle size of the support material, the highest level of methane production being obtained by the smaller particle size sepiolite. Because of the porosity and physico-chemical characteristics of these support materials, the anaerobic microbial consortia formed quickly (after one week of incubation). The predominant methanogenic bacteria present in the active granules, detected both by immunofluorescence using specific antibodies and by scanning electron microscopy, were acetoclastic methanogens, mainly Methanosarcina and Methanosaeta.

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

    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.

  15. Modeling Fluid and Heat Transport in a New Type Thermal Isomerization Fluidized Bed Reactor

    Science.gov (United States)

    Yang, Xiaoxiao; Fu, Zewu; Zhao, Yuying; Liu, Liujun; Li, Rui

    2017-10-01

    In the current work, with a new concept of resident ratio which impacts the reaction time, a fluid flow and heat transfer model were employed for simulating pressure drop, temperature profile and fluid flow properties of new type thermal isomerization reactor. The thermal isomerization experiment of β-pinenewas performed using the reactor. Momentum equation, energy equation and kinetic equationswere used to describe the fluid flow and heat transfer. The experimental results were in good agreement with theoretical simulation which indicated that the temperature difference between boundary and initial can be decreased by using steel balls and this modified fluidized bed can improve the yield and selectivity of the products effectively.

  16. Typical Application of Sound Field in Wastewater Treatment with Fluidized Bed Photocatalytic Reactor.

    Science.gov (United States)

    Si, Chong-dian; Zhou, Jing; Gao, Hong-tao; Liu, Guang-jun; Wu, Jian-jun

    2015-04-01

    The effect of a sound field on wastewater treatment with a fluidized bed photocatalytic reactor (FBPR) was investigated. With Alizarin Green (AG) being the sole infectant, the Fe-doped TiO2 catalyst prepared was used as the fluidized media. According to the Langmuir-Hinshelwood model, the photocatalytic degradation follows the pseudo-first-order reaction kinetics with respect to the concentration of AG. Sound field application allowed the fluidization of the fine powder at high liquid flow rates; thus, the mass transfer rate between organic pollutant and particle photocatalyst was enhanced and the efficiency of degradation was increased. As expected, the degradation rate constant increased with increasing sound pressure level, as well as increased with increasing sound frequency ranging from 50 to 100 Hz, then further decreased with increasing sound frequency from 100 to 200 Hz. In addition, Fe doping is also responsible for the enhanced photocurrent response of the Fe-doped TiO2 nanoparticle in FBPR relative to pure TiO2.

  17. Comparison of the Effects of Fluidized-Bed and Fixed-Bed Reactors in Microwave-Assisted Catalytic Decomposition of TCE by Hydrogen

    Directory of Open Access Journals (Sweden)

    Lili Ren

    2012-01-01

    Full Text Available Trichloroethylene (TCE decomposition by hydrogen with microwave heating under different reaction systems was investigated. The activities of a series of catalysts for microwave-assisted TCE hydrodechlorination were tested through the fixed-bed and the fluidized-bed reactor systems. This study found that the different reaction system is suitable for different catalyst type. And there is an interactive relationship between the catalyst type and the reaction bed type.

  18. A Simple Analytical Method for Determining Basic Hydrodynamic Characteristics of Hybrid Fluidized-Bed Air-Lift Apparatae

    Directory of Open Access Journals (Sweden)

    Tabiś Bolesław

    2017-03-01

    Full Text Available A simple analytical method for determination of basic hydrodynamic characteristics of hybrid fluidized-bed air-lift devices was presented. These devices consist of two parts: a two-phase air-lift part and a two-phase liquid-solid fluidized-bed part. Forced circulation of fluid in the air-lift part is used for fluidization of solid particles in the fluidized-bed part. According to the opinion given in the literature, if such apparatus is used for aerobic microbiological processes, its advantage is lower shear forces acting on the biofilm immobilized on fine-grained material compared with shear forces in three-phase fluidized-bed bioreactors. Another advantage is higher biomass concentration due to its immobilization on fine particles, compared with two-phase airlift bioreactors. A method of calculating gas hold-up in the air-lift part, and gas and liquid velocities in all zones of the analyzed apparatus is presented.

  19. Technical notes for the conceptual design for an atmospheric fluidized-bed direct combustion power generating plant. [570 MWe plant

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-04-01

    The design, arrangement, thermodynamics, and economics of a 578 MW(e) (nominal gross) electric power generating plant equipped with a Foster Wheeler Energy Corporation (FWEC) atmospheric fluidized bed (AFB) boiler are described. Information is included on capital and operating costs, process systems, electrical systems, control and instrumentation, and environmental systems. This document represents a portion of an overall report describing the conceptual designs of two atmospheric fluidized bed boilers and balance of plants for the generation of electric power and the analysis and comparison of these conceptual designs to a conventional pulverized coal-fired electric power generation plant equipped with a wet limestone flue gas desulfurization system.

  20. 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.

  1. Technical notes for the conceptual design for an atmospheric fluidized-bed direct combustion power generating plant. [570 MWe plant

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-04-01

    The design, arrangement, thermodynamics, and economics of a 592 MW(e) (nominal gross) electric power generating plant equipped with a Babcock and Wilcox Company (B and W) atmospheric fluidized bed (AFB) boiler are described. Information is included on capital and operating costs, process systems, electrical systems, control and instrumentation, and environmental systems. This document represents a portion of an overall report describing the conceptual designs of two atmospheric fluidized bed boilers and balance of plants for the generation of electric power and the analysis and comparison of these conceptual designs to a conventional pulverized coal-fired electric power generation plant equipped with a wet limestone flue gas desulfurization system.

  2. Electrochemical struvite precipitation from digestate with a fluidized bed cathode microbial electrolysis cell

    KAUST Repository

    Cusick, Roland D.

    2014-05-01

    Microbial electrolysis cells (MECs) can be used to simultaneously convert wastewater organics to hydrogen and precipitate struvite, but scale formation at the cathode surface can block catalytic active sites and limit extended operation. To promote bulk phase struvite precipitation and minimize cathode scaling, a two-chamber MEC was designed with a fluidized bed to produce suspended particles and inhibit scale formation on the cathode surface. MEC operation elevated the cathode pH to between 8.3 and 8.7 under continuous flow conditions. Soluble phosphorus removal using digester effluent ranged from 70 to 85% with current generation, compared to 10-20% for the control (open circuit conditions). At low current densities (≤2mA/m2), scouring of the cathode by fluidized particles prevented scale accumulation over a period of 8 days. There was nearly identical removal of soluble phosphorus and magnesium from solution, and an equimolar composition in the collected solids, supporting phosphorus removal by struvite formation. At an applied voltage of 1.0V, energy consumption from the power supply and pumping (0.2Wh/L, 7.5Wh/g-P) was significantly less than that needed by other struvite formation methods based on pH adjustment such as aeration and NaOH addition. In the anode chamber, current generation led to COD oxidation (1.1-2.1g-COD/L-d) and ammonium removal (7-12mM) from digestate amended with 1g/L of sodium acetate. These results indicate that a fluidized bed cathode MEC is a promising method of sustainable electrochemical nutrient and energy recovery method for nutrient rich wastewaters. © 2014 Elsevier Ltd.

  3. Numerical simulation of flow hydrodynamics of struvite pellets in a liquid-solid fluidized bed.

    Science.gov (United States)

    Ye, Xin; Chu, Dongyuan; Lou, Yaoyin; Ye, Zhi-Long; Wang, Ming Kuang; Chen, Shaohua

    2017-07-01

    Phosphorus recovery in the form of struvite has been aroused in recent decades for its dual advantages in eutrophication control and resource protection. The usage of the struvite products is normally determined by the size which is largely depended on the hydrodynamics. In this study, flow behavior of struvite pellets was simulated by means of Eulerian-Eulerian two-fluid model combining with kinetic theory of granular flow in a liquid-solid fluidized bed reactor (FBR). A parametric study including the mesh size, time step, discretization strategy, turbulent model and drag model was first developed, followed by the evaluations of crucial operational conditions, particle characteristics and reactor shapes. The results showed that a cold model with the mesh resolution of 16×240, default time step of 0.001sec and first order discretization scheme was accurate enough to describe the fluidization. The struvite holdup profile using Syamlal-O'Brien drag model was best fitted to the experimental data as compared with other drag models and the empirical Richardson-Zaki equation. Regarding the model evaluation, it showed that liquid velocity and particle size played important roles on both solid holdups and velocities. The reactor diameter only influenced the solid velocity while the static bed height almost took no effect. These results are direct and can be applied to guide the operation and process control of the struvite fluidization. Moreover, the model parameters can also be used as the basic settings in further crystallization simulations. Copyright © 2016. Published by Elsevier B.V.

  4. Biological upflow fluidized bed denitrification reactor demonstration project-Stamford, Ct.

    Energy Technology Data Exchange (ETDEWEB)

    Semon, J.; Palumbo, D.; Schede, R.; Santoro, M.; Schneider, M.; Lesando, S. [City of Stamford, CT (United States); Sadick, T. [CH2M Hill, Newport News, VA (United States)

    1994-12-31

    Results of a demonstration project using a biological upflow fluidized bed reactor to remove nitrogen from wastewater treatment plant effluent are described. The reactor was operated at a flow rate of 15.14 L/s and a loading of 2371 kg NO{sub 3}/1,000 m{sup 3}/d. Problems were encountered with the mechanical systems during start-up, but they were resolved and the system has performed extremely well throughout the test period. Performance data obtained from this project are very encouraging. Nitrate removal averaged 97% with effluent total nitrogen concentrations between 1.5 to 2.0 mg/l at 15 C. Approximately 3 mgs of methanol per mg of influent nitrate is used as a carbon source. Reactor empty bed contact time averaged 5.5 minutes. It appears that this type of process can be used successfully to remove nitrogen to meet low discharge concentrations at relatively low temperatures.

  5. Impact of fluidized bed combustion waste on metal content of crops and soil

    Energy Technology Data Exchange (ETDEWEB)

    Mays, D.A.; Giordano, P.M.; Behel, A.D. Jr. (Tennessee Valley Authority, Muscle Shoals, AL (USA). Agricultural Research Dept.)

    1991-08-01

    The fluidized bed combustion process for removing SO{sub 2} from coal-fired power plant stack gases results in generation of large tonnages of waste requiring environmentally acceptable storage or disposal. A field study was initiated in fall 1985 to determine limits of fluidized bed combustion wasted (FBCW) applications to agronomic crops without causing significant yield reduction or accumulation of heavy metals in plants or the soil. Rates of FBCW ranging from 22 to 560 t ha{sup -1} were incorporated in soil by plowing down single and split applications. Conventional agricultural lime treatments were included for comparison. Tall fescue ({ital Festuca arundinacea}), alfalfa ({ital Medicago sativa L.}), corn ({ital Zea mays L.}), and soybeans ({ital Glycine max. L.}) were grown from 1986-88. Annual applications of 22 t ha{sup -1} did not affect yield or metal uptake of any test crop. A single 112 t ha{sup -1} application had no adverse effect, but repeated applications of that rate lowered corn and soybean yields. The rate of 560 t ha{sup -1} resulted in depressed or eliminated growth of all crops. A high pH and high concentrations of Ca and S were associated with this rate but heavy metals and B concentrations in soil and plant tissue were not significantly affected. 7 refs., 12 tabs.

  6. Fluidized bed treatment of rapeseed meal and cake as possibility for the production of canolol

    Directory of Open Access Journals (Sweden)

    Pudel Frank

    2014-01-01

    Full Text Available Canolol (2,6-dimethoxy-4-vinylphenol, 4-vinylsyringol, which is formed by thermally initiated CO2splitting off from sinapic acid, possesses a high antioxidant potential. Furthermore different positive physiological properties are described. Due to rapeseed’s high content of phenolic acids, particularly sinapic acid, it is obvious to produce canolol as by-product of rapeseed processing. Roasting of rapeseed meal or cake in a fluidized bed followed by extraction with supercritical carbon dioxide of the formed canolol represents a production procedure which not impairs the commercial oil mill process. This article summarizes results from the roasting process with rapeseed meal and cake in fluidized bed equipments of different design and size showing that it is a suitable technique to transform sinapic acid into canolol. The achieved canolol contents are at 500 mg/kg in minimum, if the material is rapidly cooled-down after reaching the optimal temperature of 165 °C. Further roasting leads to a fast reduction of the canolol content. In addition it could be observed, that the sinapic acid content is not decreasing in the same amount as the canolol content increases. Sinapic acid seems to be “reproduced” during roasting. The reaction mechanisms of the described phenomena are not known.

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

    Science.gov (United States)

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

    2015-12-01

    Co-combusting hazardous wastes in existing fluidized bed combustors is an alternative to hazardous waste treatment facilities, in shortage in China. Tannery sludge is a kind of hazardous waste, considered fit for co-combusting with coal in fluidized bedboilers. In this work, co-combustion tests of tannery sludge and bituminous coal were conducted in a power plant in Jiaxing, Zhejiang province. Before that, the combustion behavior of tannery sludge and bituminous were studied by thermogravimetric analysis. Tannery sludge presented higher reactivity than bituminous coal. During the co-combustion tests, the emissions of harmful gases were monitored. The results showed that the pollutant emissions met the Chinese standard except for NOx. The Concentrations of seven trace elements (As, Cr, Cd, Ni, Cu, Pb, Mn) in three exit ash flows (bottom ash in bed, fly ash in filter, and submicrometer aerosol in flue gas) were analyzed. The results of mono-combustion of bituminous coal were compared with those of co-combustion with tannery sludge. It was found that chromium enriched in fly ash. At last, the leachability of fly ash and bottom ash was analyzed. The results showed that most species were almost equal to or below the limits except for As in bottom ashes and Cr in the fly ash of co-combustion test. The concentrations of Cr in leachates of co-combustion ashes are markedly higher than that of coal mono-combustion ashes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Fluidized-bed atomic layer deposition reactor for the synthesis of core-shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Didden, Arjen P.; Middelkoop, Joost; Krol, Roel van de, E-mail: roel.vandekrol@helmholtzberlin.de [Delft University of Technology, Faculty of Applied Sciences, Department of Chemical Engineering, P.O. Box 5045, 2600 GA Delft (Netherlands); Besling, Wim F. A. [NXP Semiconductors, High Tech Campus 32, 5656 AE Eindhoven (Netherlands); Nanu, Diana E. [Thin Film Factory B.V., Hemma Oddastrjitte 5, 8927 AA Leeuwarden (Netherlands)

    2014-01-15

    The design of a fluidized bed atomic layer deposition (ALD) reactor is described in detail. The reactor consists of three parts that have all been placed in one protective cabinet: precursor dosing, reactor, and residual gas treatment section. In the precursor dosing section, the chemicals needed for the ALD reaction are injected into the carrier gas using different methods for different precursors. The reactor section is designed in such a way that a homogeneous fluidized bed can be obtained with a constant, actively controlled, reactor pressure. Furthermore, no filters are required inside the reactor chamber, minimizing the risk of pressure increase due to fouling. The residual gas treatment section consists of a decomposition furnace to remove residual precursor and a particle filter and is installed to protect the pump. In order to demonstrate the performance of the reactor, SiO{sub 2} particles have been coated with TiO{sub 2} using tetrakis-dimethylamino titanium (TDMAT) and H{sub 2}O as precursors. Experiments with varying pulse times show that saturated growth can be obtained with TDMAT pulse times larger than 600 s. Analysis of the powder with High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) and energy dispersive X-ray spectroscopy confirmed that after 50 cycles, all SiO{sub 2} particles were coated with a 1.6 nm homogenous shell of TiO{sub 2}.

  9. Effects of biomass on dynamics of combustion in circulating fluidized beds

    Directory of Open Access Journals (Sweden)

    Tourunen Antti

    2004-01-01

    Full Text Available Fluidized bed technology is very suitable for the combustion of biomass Nevertheless substitution of coal with biomass affects boiler operation and especially dynamics and controllability. Non-homogeneity of biomass and fuel feeding disturbances cause process instability, such as variations in temperatures and pressures, which reduce lifetime of equipment and structures. Because of process instability higher air coefficient must be used in order to avoid CO emissions, which is not economical. Combustion profiles for coal, wood and peat, measured at the VTT Processes Pilot circulating fluidized bed reactor, have been compared. Process stability and char inventories have been studied by the measurements and the model. Biofuel are usually very reactive and their combustion profiles are quite different compared to coals. Because of high reactivity and low char content combustion process with biofuel is very sensitive for fuel feeding. Also low char inventory effect on load changes combined with combustion profile that differs from coals. Because of different combustion profile heat transfer can be a limiting factor in load changes despite the high reactivity and fast oxygen response.

  10. Fluidized-bed pyrolysis of oil shale: oil yield, composition, and kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, J H; Huss, E B; Ott, L L; Clarkson, J E; Bishop, M O; Taylor, J R; Gregory, L J; Morris, C J

    1982-09-01

    A quartz isothermal fluidized-bed reactor has been used to measure kinetics and oil properties relevant to surface processing of oil shale. The rate of oil formation has been described with two sequential first-order rate equations characterized by two rate constants, k/sub 1/ = 2.18 x 10/sup 10/ exp(-41.6 kcal/RT) s/sup -1/ and k/sub 2/ = 4.4 x 10/sup 6/ exp(-29.7 kcal/RT) s/sup -1/. These rate constants together with an expression for the appropriate weighting coefficients describe approximately 97/sup +/% of the total oil produced. A description is given of the results of different attempts to mathematically describe the data in a manner suitable for modeling applications. Preliminary results are also presented for species-selective kinetics of methane, ethene, ethane and hydrogen, where the latter is clearly distinguished as the product of a distinct intermediate. Oil yields from Western oil shale are approximately 100% Fischer assay. Oil composition is as expected based on previous work and the higher heating rates (temperatures) inherent in fluidized-bed pyrolysis. Neither the oil yield, composition nor the kinetics varied with particle size between 0.2 and 2.0 mm within experimental error. The qualitatively expected change in oil composition due to cracking was observed over the temperature range studied (460 to 540/sup 0/C). Eastern shale exhibited significantly faster kinetics and higher oil yields than did Western shale.

  11. Reduction and Immobilization of Potassium Permanganate on Iron Oxide Catalyst by Fluidized-Bed Crystallization Technology

    Directory of Open Access Journals (Sweden)

    Guang-Xia Li

    2012-03-01

    Full Text Available A manganese immobilization technology in a fluidized-bed reactor (FBR was developed by using a waste iron oxide (i.e., BT-3 as catalyst which is a by-product from the fluidized-bed Fenton reaction (FBR-Fenton. It was found that BT-3 could easily reduce potassium permanganate (KMnO4 to MnO2. Furthermore, MnO2 could accumulate on the surface of BT-3 catalyst to form a new Fe-Mn oxide. Laboratory experiments were carried out to investigate the KMnO4-reduction mechanism, including the effect of KMnO4 concentration, BT-3 dosage, and operational solution pH. The results showed that the pH solution was a significant factor in the reduction of KMnO4. At the optimum level, pHf 6, KMnO4 was virtually reduced in 10 min. A pseudo-first order reaction was employed to describe the reduction rate of KMnO4.

  12. Experimental study of biomass gasification with oxygen-enriched air in fluidized bed gasifier.

    Science.gov (United States)

    Liu, Lingqin; Huang, Yaji; Cao, Jianhua; Liu, Changqi; Dong, Lu; Xu, Ligang; Zha, Jianrui

    2018-01-17

    Considering the universality, renewability and cleanness of biomass, an experimental research is carried out using rice straw in a two-stage fluidized bed. The experimental analysis identified the relevant parameters in the operation of the two-stage fluidized bed to investigate the properties of biomass enriched air gasification. Results show that higher gasification temperature is conducive to enhance the gasification performance. An increasing ER is shown to go against adding gas heat value. When oxygen concentration increases from 21% to 45%, the gas heating value increases from 4.00MJ/kg to 5.24MJ/kg and the gasification efficiency increases from 29.60% to 33.59%, which shows higher oxygen concentration is conducive to higher quality gas and higher gasification efficiency. A secondary oxygen injection leads to reduction of tar concentration from 15.78g/Nm 3 to 10.24g/Nm 3 . The optimal secondary oxygen ratio is about 33.00%. When the secondary oxygen ratio increased to 46.86%, monocyclic aromatics reduced from 28.17% to 19.65% and PAHs increased from 34.97% to 44.05%, leading to the increase aromatization of tar. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Artificial neural network based modelling approach for municipal solid waste gasification in a fluidized bed reactor.

    Science.gov (United States)

    Pandey, Daya Shankar; Das, Saptarshi; Pan, Indranil; Leahy, James J; Kwapinski, Witold

    2016-12-01

    In this paper, multi-layer feed forward neural networks are used to predict the lower heating value of gas (LHV), lower heating value of gasification products including tars and entrained char (LHVp) and syngas yield during gasification of municipal solid waste (MSW) during gasification in a fluidized bed reactor. These artificial neural networks (ANNs) with different architectures are trained using the Levenberg-Marquardt (LM) back-propagation algorithm and a cross validation is also performed to ensure that the results generalise to other unseen datasets. A rigorous study is carried out on optimally choosing the number of hidden layers, number of neurons in the hidden layer and activation function in a network using multiple Monte Carlo runs. Nine input and three output parameters are used to train and test various neural network architectures in both multiple output and single output prediction paradigms using the available experimental datasets. The model selection procedure is carried out to ascertain the best network architecture in terms of predictive accuracy. The simulation results show that the ANN based methodology is a viable alternative which can be used to predict the performance of a fluidized bed gasifier. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Comparison of an industrial FCC plant with a small internally circulating fluidized bed pilot plant

    Energy Technology Data Exchange (ETDEWEB)

    Reichhold, A.; Fimberger, W.; Hofbauer, H. [Technische Univ., Vienna (Austria). Inst. of Chemical Engineering

    1999-07-01

    A reaction/regeneration system with an internally circulating fluidized bed designed by Hofbauer and Reichhold is used for catalytic cracking. A hot unit with an internally circulating fluidized bed (reactor diameter 200 mm; reactor height 2500 mm; feed rate 5 kg/h) is used to reflect the operating conditions in large plants. The aim is to obtain the same product composition as a typical large industrial FCC plant. Experiments at different feed rates, different Cat to Oil (C/O) ratios and different riser and regenerator temperatures were carried out successfully. Operating conditions could be determined where the product quality obtained in the pilot plant exactly matched that of the industrial FCC-plant (gas 17%wt; gasoline 52%wt; residue (LCO + HCO) 26%wt; coke 5%wt). The reactor size allows the results to be viewed with more confidence than these from e.g. micro activity tests (MAT). Therefore, the plant can be used for testing different feedstocks, additives and catalysts for use in an industrial plant. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-31

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

  16. A CFD model for biomass fast pyrolysis in fluidized-bed reactors

    Science.gov (United States)

    Xue, Qingluan; Heindel, T. J.; Fox, R. O.

    2010-11-01

    A numerical study is conducted to evaluate the performance and optimal operating conditions of fluidized-bed reactors for fast pyrolysis of biomass to bio-oil. A comprehensive CFD model, coupling a pyrolysis kinetic model with a detailed hydrodynamics model, is developed. A lumped kinetic model is applied to describe the pyrolysis of biomass particles. Variable particle porosity is used to account for the evolution of particle physical properties. The kinetic scheme includes primary decomposition and secondary cracking of tar. Biomass is composed of reference components: cellulose, hemicellulose, and lignin. Products are categorized into groups: gaseous, tar vapor, and solid char. The particle kinetic processes and their interaction with the reactive gas phase are modeled with a multi-fluid model derived from the kinetic theory of granular flow. The gas, sand and biomass constitute three continuum phases coupled by the interphase source terms. The model is applied to investigate the effect of operating conditions on the tar yield in a fluidized-bed reactor. The influence of various parameters on tar yield, including operating temperature and others are investigated. Predicted optimal conditions for tar yield and scale-up of the reactor are discussed.

  17. Fluid dynamics model on fluidized bed gasifier using agro-industrial biomass as fuel.

    Science.gov (United States)

    Ismail, Tamer M; Abd El-Salam, M; Monteiro, Eliseu; Rouboa, Abel

    2017-06-21

    The present study shows the experimental and numerical results of thermal gasification of biomass, on the energy potential of agro-industrial waste from the Portalegre region. Gasification tests were performed in a pilot-scale fluidized bed gasifier, in order to study the behavior of peach stones and miscanthus to investigate the effect of gasification temperatures at 750°C, 800°C and 850°C at a constant biomass flow rate of 45kg/h. In order to optimize the operating conditions of the biomass gasification process, a numerical model is developed namely COMMENT code. This model is a computer model of two dimensions describing the biomass gasification processes in a fluidized bed gasifier using peach stone and miscanthus as fuel. Both phases, solid and gaseous, were described using an Eulerian-Eulerian approach exchanging mass, energy, and momentum. The numerical model results are then compared with experimental results. The produced results show the impact of the increased temperature in the calorific value of the syngas. The tests carried out at 750°C shown an increase in CO2 and N2 and a decrease of CO in the range of 5% comparing to the tests carried out at 850°C. In addition, increased temperature favors a decrease in tar production in thermal gasification process. Numerical results shows to be in good agreement with the experimental data. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-11-01

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

  19. A statistical experimental design to remove sulfate by crystallization in a fluidized-bed reactor

    Directory of Open Access Journals (Sweden)

    Mark Daniel G. de Luna

    2017-05-01

    Full Text Available This study used crystallization in a fluidized-bed reactor as an alternative technology to the conventional chemical precipitation to remove sulfate. The Box-Behnken Design was used to study the effects and interactions of seed dosage of synthetic gypsum, initial sulfate concentration and molar ratio of calcium to sulfate on conversion and removal of sulfate. The optimum conditions of conversion and removal of sulfate were determined and used to treat the simulated acid mine drainage (AMD wastewater. The effect of inorganic ions CO32−, NH4+ and Al3+ on sulfate conversion was also investigated. Experimental results indicated that seed dosage, initial sulfate concentration and molar ratio of calcium to sulfate are all significant parameters in the sulfate removal by fluidized-bed crystallization. The optimal conditions of 4 g seed L−1, 119.7 mM of initial sulfate concentration and [Ca2+]/[SO42−] molar ratio of 1.48 resulted in sulfate conversion of 82% and sulfate removal of 67%. Conversion and removal of sulfate in the simulated AMD wastewater were 79 and 63%, respectively. When ammonium or aluminum was added to the synthetic sulfate wastewater, significant conversion of sulfate was achieved.

  20. Numerical investigation of solid mixing in a fluidized bed coating process

    Science.gov (United States)

    Kenche, Venkatakrishna; Feng, Yuqing; Ying, Danyang; Solnordal, Chris; Lim, Seng; Witt, Peter J.

    2013-06-01

    Fluidized beds are widely used in many process industries including the food and pharmaceutical sectors. Despite being an intensive research area, there are no design rules or correlations that can be used to quantitatively predict the solid mixing in a specific system for a given set of operating conditions. This paper presents a numerical study of the gas and solid dynamics in a laboratory scale fluidized bed coating process used for food and pharmaceutical industries. An Eulerian-Eulerian model (EEM) with kinetic theory of granular flow is selected as the modeling technique, with the commercial computational fluid dynamics (CFD) software package ANSYS/Fluent being the numerical platform. The flow structure is investigated in terms of the spatial distribution of gas and solid flow. The solid mixing has been evaluated under different operating conditions. It was found that the solid mixing rate in the horizontal direction is similar to that in the vertical direction under the current design and operating conditions. It takes about 5 s to achieve good mixing.

  1. 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.

  2. High efficiency chlorine removal from polyvinyl chloride (PVC) pyrolysis with a gas-liquid fluidized bed reactor.

    Science.gov (United States)

    Yuan, G; Chen, D; Yin, L; Wang, Z; Zhao, L; Wang, J Y

    2014-06-01

    In this research a gas-liquid fluidized bed reactor was developed for removing chlorine (Cl) from polyvinyl chloride (PVC) to favor its pyrolysis treatment. In order to efficiently remove Cl within a limited time before extensive generation of hydrocarbon products, the gas-liquid fluidized bed reactor was running at 280-320 °C, where hot N2 was used as fluidizing gas to fluidize the molten polymer, letting the molten polymer contact well with N2 to release Cl in form of HCl. Experimental results showed that dechlorination efficiency is mainly temperature dependent and 300 °C is a proper reaction temperature for efficient dechlorination within a limited time duration and for prevention of extensive pyrolysis; under this temperature 99.5% of Cl removal efficiency can be obtained within reaction time around 1 min after melting is completed as the flow rate of N2 gas was set around 0.47-0.85 Nm(3) kg(-1) for the molten PVC. Larger N2 flow rate and additives in PVC would enhance HCl release but did not change the final dechlorination efficiency; and excessive N2 flow rate should be avoided for prevention of polymer entrainment. HCl is emitted from PVC granules or scraps at the mean time they started to melt and the melting stage should be taken into consideration when design the gas-liquid fluidized bed reactor for dechlorination. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Spray-dried fluid-bed sorbents tests - CMP-5

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

    The objective of this study is to determine the feasibility of manufacturing highly reactive and attrition-resistant zinc titanate sorbents by spray drying, suitable for bubbling (conventional) as well as transport-type fluidized-bed reactor systems.

  4. In situ CO{sub 2} capture in a dual fluidized bed biomass steam gasifier - bed material and fuel variation

    Energy Technology Data Exchange (ETDEWEB)

    Soukup, G.; Pfeifer, C.; Kreuzeder, A.; Hofbauer, H. [Institute of Chemical Engineering, Vienna University of Technology, Vienna (Austria)

    2009-03-15

    The AER (absorption enhanced reforming) process, based on the dual fluidized bed steam gasification process, uses a bed material which, apart from its function as heat carrier, acts as a CO{sub 2} transporting agent and selectively transfers CO{sub 2} from the gasification reactor to the combustion reactor. Thus, a hydrogen-rich gas is produced (H{sub 2} 55..70 vol.-%{sub db}, CH{sub 4} 8..13 vol.-%{sub db}, CO 5..11 vol.-%{sub db} as well as CO{sub 2} 7..20 vol.-%{sub db}). Seven different CaO containing bed materials were tested for their principal applicability to the AER process with special focus on their influence on tar production. The amount of tars was generally found to be five times lower than with conventional gasification (at 850 C) despite the low gasification temperatures (600-700 C). Due to these low gasification temperatures, biomass with high alkali contents (e.g., straw), indicating a low ash melting point (< 800 C), can be used under AER conditions. In summary, the AER process is very effective owing to the integration of the heat of the chemical reaction of CO{sub 2} with CaO and the water-gas shift reaction, which are both exothermic, into the gasification and the internal reforming of primary and secondary tars, which cuts off the formation of higher tars. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  5. Dynamic modeling of a solar receiver/thermal energy storage system based on a compartmented dense gas fluidized bed

    Science.gov (United States)

    Solimene, Roberto; Chirone, Roberto; Chirone, Riccardo; Salatino, Piero

    2017-06-01

    Fluidized beds may be considered a promising option to collection and storage of thermal energy of solar radiation in Concentrated Solar Power (CSP) systems thanks to their excellent thermal properties in terms of bed-to-wall heat transfer coefficient and thermal diffusivity and to the possibility to operate at much higher temperature. A novel concept of solar receiver for combined heat and power (CHP) generation consisting of a compartmented dense gas fluidized bed has been proposed to effectively accomplish three complementary tasks: collection of incident solar radiation, heat transfer to the working fluid of the thermodynamic cycle and thermal energy storage. A dynamical model of the system laid the basis for optimizing collection of incident radiative power, heat transfer to the steam cycle, storage of energy as sensible heat of bed solids providing the ground for the basic design of a 700kWth demonstration CSP plant.

  6. Release of alkali salts and coal volatiles affecting internal components in fluidized bed combustion systems

    Directory of Open Access Journals (Sweden)

    Arias del Campo, E.

    2003-12-01

    Full Text Available In spite of the potential advantages of atmospheric fluidized bed systems, experience has proved that, under certain environments and operating conditions, a given material employed for internal components could lead to catastrophic events. In this study, an attempt is made to establish material selection and operational criteria that optimize performance and availability based on theoretical considerations of the bed hydrodynamics, thermodynamics and combustion process. The theoretical results may indicate that, for high-volatile coals with particle diameters (dc of 1-3 mm and sand particle size (ds of 0.674 mm, a considerable proportion of alkali chlorides may be transferred into the freeboard region of fluidized bed combustors as vapor phase, at bed temperatures (Tb < 840 °C, excess air (XSA ≤ 20 %, static bed height (Hs ≤ 0.2 m and fluidizing velocity (Uo < 1 m/s. Under these operating conditions, a high alkali deposition may be expected to occur in heat exchange tubes located above the bed. Conversely, when the combustors operate at Tb > 890 °C and XSA > 30 %, a high oxidation rate of the in-bed tubes may be present. Nevertheless, for these higher Tb values and XSA < 10 %, corrosion attack of metallic components, via sulfidation, would occur since the excessive gas-phase combustion within the bed induced a local oxygen depletion.

    A pesar de las ventajas potenciales de los sistemas atmosféricos de lecho fluidizado, la experiencia ha demostrado que, bajo ciertas atmósferas y condiciones de operación, un material que se emplea como componente interno podría experimentar una falla y conducir a eventos catastróficos. En este estudio, se intenta establecer un criterio tanto operativo como de selección del material que permita optimizar su disponibilidad y funcionalidad basados en consideraciones teóricas de la hidrodinámica del lecho, la termodin

  7. Some Laws Governing Twisted Two-Phase Flows in the over-Bed Space of a Fluidized Bed of Finely Divided Particles

    Science.gov (United States)

    Pitsukha, E. A.; Teplitskii, Yu. S.; Borodulya, V. A.

    2015-01-01

    As a result of experimental investigation of the hydrodynamics of a twisted air flow above a fluidized bed, the character of the effect of particle entrainment from the latter on the distribution of air velocities and pressure in the vortex zone has been established.

  8. Fluidized-Bed Bioreactor Applications for Biological Wastewater Treatment: A Review of Research and Developments

    Directory of Open Access Journals (Sweden)

    Michael J. Nelson

    2017-06-01

    Full Text Available Wastewater treatment is a process that is vital to protecting both the environment and human health. At present, the most cost-effective way of treating wastewater is with biological treatment processes such as the activated sludge process, despite their long operating times. However, population increases have created a demand for more efficient means of wastewater treatment. Fluidization has been demonstrated to increase the efficiency of many processes in chemical and biochemical engineering, but it has not been widely used in large-scale wastewater treatment. At the University of Western Ontario, the circulating fluidized-bed bioreactor (CFBBR was developed for treating wastewater. In this process, carrier particles develop a biofilm composed of bacteria and other microbes. The excellent mixing and mass transfer characteristics inherent to fluidization make this process very effective at treating both municipal and industrial wastewater. Studies of lab- and pilot-scale systems showed that the CFBBR can remove over 90% of the influent organic matter and 80% of the nitrogen, and produces less than one-third as much biological sludge as the activated sludge process. Due to its high efficiency, the CFBBR can also be used to treat wastewaters with high organic solid concentrations, which are more difficult to treat with conventional methods because they require longer residence times; the CFBBR can also be used to reduce the system size and footprint. In addition, it is much better at handling and recovering from dynamic loadings (i.e., varying influent volume and concentrations than current systems. Overall, the CFBBR has been shown to be a very effective means of treating wastewater, and to be capable of treating larger volumes of wastewater using a smaller reactor volume and a shorter residence time. In addition, its compact design holds potential for more geographically localized and isolated wastewater treatment systems.

  9. Autothermal reforming of methane with integrated CO2 capture in a novel fluidized bed membrane reactor. Part 1: experimental demonstration

    NARCIS (Netherlands)

    Gallucci, F.; van Sint Annaland, M.; Kuipers, J.A.M.

    2008-01-01

    Two fluidized bed membrane reactor concepts for hydrogen production via autothermal reforming of methane with integrated CO2 capture are proposed. Ultra-pure hydrogen is obtained via hydrogen perm-selective Pd-based membranes, while the required reaction energy is supplied by oxidizing part of the

  10. Pure hydrogen production via autothermal reforming of ethanol in a fluidized bed membrane reactor: A simulation study

    NARCIS (Netherlands)

    Gallucci, F.; van Sint Annaland, M.; Kuipers, J.A.M.

    2010-01-01

    In this paper the production of ultra-pure hydrogen via autothermal reforming of ethanol in a fluidized bed membrane reactor has been studied. The heat needed for the steam reforming of ethanol is obtained by burning part of the hydrogen recovered via the hydrogen perm-selective membrane thereby

  11. Fluidized bed steam reformed mineral waste form performance testing to support Hanford Supplemental Low Activity Waste Immobilization Technology Selection

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Pierce, E. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Cozzi, A. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Crawford, C. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Daniel, W. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Herman, C. C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Miller, D. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Missimer, D. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Williams, M. F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brown, C. F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qafoku, N. P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Neeway, J. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Valenta, M. M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gill, G. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Swanberg, D. J. [Washington River Protection Solutions (WRPS), Richland, WA (United States); Robbins, R. A. [Washington River Protection Solutions (WRPS), Richland, WA (United States); Thompson, L. E. [Washington River Protection Solutions (WRPS), Richland, WA (United States)

    2015-10-01

    This report describes the benchscale testing with simulant and radioactive Hanford Tank Blends, mineral product characterization and testing, and monolith testing and characterization. These projects were funded by DOE EM-31 Technology Development & Deployment (TDD) Program Technical Task Plan WP-5.2.1-2010-001 and are entitled “Fluidized Bed Steam Reformer Low-Level Waste Form Qualification”, Inter-Entity Work Order (IEWO) M0SRV00054 with Washington River Protection Solutions (WRPS) entitled “Fluidized Bed Steam Reforming Treatability Studies Using Savannah River Site (SRS) Low Activity Waste and Hanford Low Activity Waste Tank Samples”, and IEWO M0SRV00080, “Fluidized Bed Steam Reforming Waste Form Qualification Testing Using SRS Low Activity Waste and Hanford Low Activity Waste Tank Samples”. This was a multi-organizational program that included Savannah River National Laboratory (SRNL), THOR® Treatment Technologies (TTT), Pacific Northwest National Laboratory (PNNL), Oak Ridge National Laboratory (ORNL), Office of River Protection (ORP), and Washington River Protection Solutions (WRPS). The SRNL testing of the non-radioactive pilot-scale Fluidized Bed Steam Reformer (FBSR) products made by TTT, subsequent SRNL monolith formulation and testing and studies of these products, and SRNL Waste Treatment Plant Secondary Waste (WTP-SW) radioactive campaign were funded by DOE Advanced Remediation Technologies (ART) Phase 2 Project in connection with a Work-For-Others (WFO) between SRNL and TTT.

  12. Deposition of conductive TiN shells on SiO2 nanoparticles with a fluidized bed ALD reactor

    NARCIS (Netherlands)

    Didden, A.; Hillebrand, P.; Wollgarten, M.; Dam, B.; Van de Krol, R.

    2016-01-01

    Conductive TiN shells have been deposited on SiO2 nanoparticles (10–20 nm primary particle size) with fluidized bed atomic layer deposition using TDMAT and NH3 as precursors. Analysis of the powders confirms that shell growth saturates at approximately 0.4 nm/cycle at TDMAT doses of >1.2 mmol/g of

  13. Gas−Solid Turbulent Flow in a Circulating Fluidized Bed Riser: Numerical Study of Binary Particle Systems

    NARCIS (Netherlands)

    He, Y.; Deen, N.G.; van Sint Annaland, M.; Kuipers, J.A.M.

    2009-01-01

    Numerical simulations were performed of a turbulent gas-particle multiphase flow in a circulating fluidized bed riser using a hard-sphere discrete particle model (DPM) for the particle phase and the Navier−Stokes equations for the gas phase, where the subgrid scale stresses (SGS) were modeled with

  14. Gas-solid two-phase turbulent flow in a circulating fluidized bed riser: an experimental and numerical study

    NARCIS (Netherlands)

    He, Y.; van Sint Annaland, M.; Deen, N.G.; Kuipers, J.A.M.

    2006-01-01

    Hydrodynamics of gas-particle two-phase turbulent flow in a circulating fluidized bed riser is studied experimentally by Particle Image Velocimetry (PIV) and numerically with the use of a 3D discrete hard sphere particle model (DPM). Mean particle velocities and RMS velocities are obtained and the

  15. Gas-Solid Turbulent Flow in a Circulating Fluidized Bed Riser; Numerical Study of Binary Particle Mixtures

    NARCIS (Netherlands)

    He, Y; Deen, N.G.; van Sint Annaland, M.; Kuipers, J.A.M.

    2008-01-01

    A numerical simulation was performed on a turbulent gas-particle multi-phase flow in a circulating fluidized bed riser based on a hard-sphere discrete particle model (DPM) for the particle phase and the Navier-Stokes equations for the gas phase. The sub-grid scale stresses (SGS) were modeled with

  16. Gas−Solid Turbulent Flow in a Circulating Fluidized Bed Riser: Experimental and Numerical Study of Monodisperse Particle Systems

    NARCIS (Netherlands)

    He, Y.; Deen, N.G.; van Sint Annaland, M.; Kuipers, J.A.M.

    2009-01-01

    Hydrodynamics of gas-particle two-phase turbulent flow in a circulating fluidized bed riser is studied experimentally by particle image velocimetry (PIV) and numerically with the use of a 3D discrete hard sphere particle model (DPM). The influence of the superficial gas velocity and the solids flux

  17. The diffusion model of fractal heat and mass transfer in fluidized bed a local fractional arbitrary Euler-Lagrange formula

    Directory of Open Access Journals (Sweden)

    Cheng Xu

    2015-01-01

    Full Text Available In this manuscript, the local fractional arbitrary Euler-Lagrange formula are utilized to address the diffusion model of fractal heat and mass transfer in a fluidized bed based on the Fick's law with local fractional vector calculus. This article has been corrected. Link to the correction 10.2298/TSCI150923149E

  18. Oxidative decomposition of methanol in a vibroacoustic fluidized bed of Ag-coated cenosphere core-shell catalyst

    Directory of Open Access Journals (Sweden)

    Berkowicz Gabriela

    2016-12-01

    Full Text Available The paper presents results of a study of oxidative decomposition of methanol in a fluidized bed of silver catalyst. The process of methanol oxidation was carried out on Ag-coated cenospheres core-shell catalyst. The catalyst was obtained by precipitation of silver from methanolic solution of silver nitrate on cenospheres. Cenospheres are lightweight, inert, hollow spheres, which can be easily introduced into a fluidized bed. Application of the catalyst in a form of fluidized bed should ensure good temperature equalization which is very important at low temperatures due to the possibility of generation of formaldehyde. It turned out that local hot points occur in that kind of a catalyst (in the form of a fluidized bed but with very low density, thus use of additional acoustic wave is necessary to ensure good control over the temperature of the process. The products of the process of methanol oxidation were monitored on-line by Fourier transform infrared spectroscopy (FTIR. The catalyst has proven to be highly active in the oxidative decomposition of methanol. Full of methanol conversion in reaction of complete oxidation was achieved at 350°C.

  19. Physicochemical properties and gasification reactivity of the ultrafine semi-char derived from a bench-scale fluidized bed gasifier

    Science.gov (United States)

    Zhang, Yukui; Zhang, Haixia; Zhu, Zhiping; Na, Yongjie; Lu, Qinggang

    2017-08-01

    Zhundong coalfield is the largest intact coalfield worldwide and fluidized bed gasification has been considered as a promising way to achieve its clean and efficient utilization. The purpose of this study is to investigate the physicochemical properties and gasification reactivity of the ultrafine semi-char, derived from a bench-scale fluidized bed gasifier, using Zhundong coal as fuel. The results obtained are as follows. In comparison to the raw coal, the carbon and ash content of the semi-char increase after partial gasification, but the ash fusion temperatures of them show no significant difference. Particularly, 76.53% of the sodium in the feed coal has released to the gas phase after fluidized bed gasification. The chemical compositions of the semi-char are closely related to its particle size, attributable to the distinctly different natures of diverse elements. The semi-char exhibits a higher graphitization degree, higher BET surface area, and richer meso- and macropores, which results in superior gasification reactivity than the coal char. The chemical reactivity of the semi-char is significantly improved by an increased gasification temperature, which suggests the necessity of regasification of the semi-char at a higher temperature. Consequently, it will be considered feasible that these carbons in the semi-char from fluidized bed gasifiers are reclaimed and reused for the gasification process.

  20. CFD modeling of space-time evolution of fast pyrolysis products in a bench-scale fluidized-bed reactor

    Science.gov (United States)

    A model for the evolution of pyrolysis products in a fluidized bed has been developed. In this study the unsteady constitutive transport equations for inert gas flow and decomposition kinetics were modeled using the commercial computational fluid dynamics (CFD) software FLUENT-12. The model system d...

  1. Fluidized bed catalytic pyrolysis of eucalyptus over hzsm-5: effect of acid density and ga modification on catalyst deactivation

    Science.gov (United States)

    Catalytic fast pyrolysis of eucalyptus wood was performed on a continuous laboratory scale fluidized bed fast pyrolysis system. Catalytic activity was monitored from use of fresh catalyst up to a cumulative biomass to catalyst ratio (B/C) of 4/1 over extruded pellets of three different ZSM-5 catalys...

  2. User's manual for atmospheric fluidized bed combustor system economic performance algorithm computer program. [AFBCIBM

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    The computer program calculates several economic and energy terms, given various performance and cost parameters, for a system composed of coal, a coal beneficiation (cleaning) plant, a combustor plant and an associated flue gas desulfurization (FGD) plant. The combustor can be either an atmospheric fluidized bed combustor (AFBC) or a conventional pulverized (CP) combustor. The FGD system is a lime-slurry system.

  3. Development and application of a process window for achieving high-quality coating in a fluidized bed coating process

    NARCIS (Netherlands)

    Laksmana, F.L.; Hartman Kok, P.J.A.; Vromans, H.; Frijlink, H.W.; Van Der Voort Maarschalk, K.

    Next to the coating formulation, process conditions play important roles in determining coating quality. This study aims to develop an operational window that separates layering from agglomeration regimes and, furthermore, the one that leads to the best coating quality in a fluidized bed coater. The

  4. Reduction of nitrogen oxides by injection of urea in the freeboard of a pilot scale fluidized bed combustor

    NARCIS (Netherlands)

    Knol, Koen E.; Bramer, Eduard A.; Valk, M.

    1989-01-01

    The ‘thermal deNOx’ process using urea has been investigated in a 1 MW fluidized bed combustor. NOx reductions of up to 76% were obtainable by using this method. The experimental results show that urea is at least as active as NH3, which is commonly used in this application, but which is far more

  5. Investigation into adsorption and photocatalytic degradation of gaseous benzene in an annular fluidized bed photocatalytic reactor.

    Science.gov (United States)

    Geng, Qijin; Tang, Shankang; Wang, Lintong; Zhang, Yunchen

    2015-01-01

    The adsorption and photocatalytic degradation of gaseous benzene were investigated considering the operating variables and kinetic mechanism using nano-titania agglomerates in an annular fluidized bed photocatalytic reactor (AFBPR) designed. The special adsorption equilibrium constant, adsorption active sites, and apparent reaction rate coefficient of benzene were determined by linear regression analysis at various gas velocities and relative humidities (RH). Based on a series of photocatalytic degradation kinetic equations, the influences of operating variables on degradation efficiency, apparent reaction rate coefficient and half-life were explored. The findings indicated that the operating variables have obviously influenced the adsorption/photocatalytic degradation and corresponding kinetic parameters. In the photocatalytic degradation process, the relationship between photocatalytic degradation efficiency and RH indicated that water molecules have a dual-function which was related to the structure characteristics of benzene. The optimal operating conditions for photocatalytic degradation of gaseous benzene in AFBPR were determined as the fluidization number at 1.9 and RH required related to benzene concentration. This investigation highlights the importance of controlling RH and benzene concentration in order to obtain the desired synergy effect in photocatalytic degradation processes.

  6. The preparation of the sustained release metformin hydrochloride microcapsules by the Wurster fluidized bed.

    Science.gov (United States)

    Cao, Jin; Liu, Hongfei; Pan, Weisan; Sun, Changshan; Feng, Yingshu; Zhong, Hui; Shi, Shuang Shuang; He, Yan

    2014-07-01

    The main objective of this study was to prepare sustained release metformin hydrochloride microcapsules by the Wurster fluidized bed and to obtain the optimized coating process and formulation. Fine microcapsules without agglomeration were obtained in a continuous coating process with the atomization air pressure of 0.2Mpa and an appropriate coating speed temperature. With other design variables of coating process fixed, the effects of different fluidizing air volume, coating temperature, coating speed, coating material, coating materials amount, plasticizer type and plasticizer amount on drug release were investigated respectively. Coating solution was achieved by dissolving EC45cps of 21 g, EC100cps of 7 g, DBS of 2.8 g and talcum powder of 8 g in ethanol to get a final volume of 500 ml. Particles of 150g along with 500mL coating solution would be fine. The results showed that with the air volume of 35 m3•h-1, coating temperature of 35o, coating speed of 6 mL•min-1 and proper amount of coating solution, fine microcapsules were obtained. The mean diameter of the microcapsules obtained eventually were 213 μm and the drug content were 23%, which was suitable for producing a suspension. Particle diameter distribution corresponded to the normal distribution and obviously prolonged drug-release was achieved.

  7. Separation Process of Fine Coals by Ultrasonic Vibration Gas-Solid Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2017-01-01

    Full Text Available Ultrasonic vibration gas-solid fluidized bed was proposed and introduced to separate fine coals (0.5–0.125 mm fraction. Several technological methods such as XRF, XRD, XPS, and EPMA were used to study the composition of heavy products to evaluate the separation effect. Results show that the ultrasonic vibration force field strengthens the particle separation process based on density when the vibration frequency is 35 kHz and the fluidization number is 1.8. The ash difference between the light and heavy products and the recovery of combustible material obtain the maximum values of 47.30% and 89.59%, respectively. The sulfur content of the heavy product reaches the maximum value of 6.78%. Chemical state analysis of sulfur shows that organic sulfur (-C-S-, sulfate-sulfur (-SO4, and pyrite-sulfur (-S2 are confirmed in the original coal and heavy product. Organic sulfur (-C-S- is mainly concentrated in the light product, and pyrite-sulfur (-S2 is significantly enriched in the heavy product. The element composition, phase composition, backscatter imagery, and surface distribution of elements for heavy product show concentration of high-density minerals including pyrite, quartz, and kaolinite. Some harmful elements such as F, Pb, and As are also concentrated in the heavy product.

  8. Preparation and Characterization of Inorganic PCM Microcapsules by Fluidized Bed Method

    Directory of Open Access Journals (Sweden)

    Svetlana Ushak

    2016-01-01

    Full Text Available The literature shows that inorganic phase change materials (PCM have been very seldom microencapsulated, so this study aims to contribute to filling this research gap. Bischofite, a by-product from the non-metallic industry identified as having good potential to be used as inorganic PCM, was microencapsulated by means of a fluidized bed method with acrylic as polymer and chloroform as solvent, after compatibility studies of both several solvents and several polymers. The formation of bischofite and pure MgCl2·6H2O microcapsules was investigated and analyzed. Results showed an efficiency in microencapsulation of 95% could be achieved when using 2 min of fluidization time and 2 kg/h of atomization flow. The final microcapsules had excellent melting temperatures and enthalpy compared to the original PCM, 104.6 °C and 95 J/g for bischofite, and 95.3 and 118.3 for MgCl2·6H2O.

  9. Fructose Production by Inulinase Covalently Immobilized on Sepabeads in Batch and Fluidized Bed Bioreactor

    Directory of Open Access Journals (Sweden)

    Gabriele Iorio

    2010-03-01

    Full Text Available The present work is an experimental study of the performance of a recently designed immobilized enzyme: inulinase from Aspergillus sp. covalently immobilized on Sepabeads. The aim of the work is to test the new biocatalyst in conditions of industrial interest and to assess the feasibility of the process in a fluidized bed bioreactor (FBBR. The catalyst was first tested in a batch reactor at standard conditions and in various sets of conditions of interest for the process. Once the response of the catalyst to different operating conditions was tested and the operational stability assessed, one of the sets of conditions tested in batch was chosen for tests in FBBR. Prior to reaction tests, preliminary fluidization tests were realized in order to define an operating range of admissible flow rates. As a result, the FBR was run at different feed flow rates in a closed cycle configuration and its performance was compared to that of the batch system. The FBBR proved to be performing and suitable for scale up to large fructose production.

  10. 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

  11. High-efficiency treatment of PTA wastewater using a biogas jet assisted anaerobic fluidized bed reactor.

    Science.gov (United States)

    Zhang, Wei; Feng, Yangyang; Chen, Yingwen; Li, Peiwen; Zhu, Shemin; Shen, Shubao

    2018-01-15

    In this paper, a new type of biogas jet assisted anaerobic fluidized bed reactor loaded with a polypropylene (PP) carrier, has been proposed. There was a clear improvement in the fluidized state due to the biogas assisted input when the gas/water ratio was set at 1:3 with a suitable carrier loading of 60%. When the circulating water flow is 30 L/min assisted with biogas 10 L/min, the mixing time shortens from 26 s to 18 s. The performance of anaerobic biodegradation on wastewater treatment was improved largely. The chemical oxygen demand (COD) and terepthallic acid (TA) removal efficiencies were at 85.4% and 84% respectively at HRT of 20h, even when the influent COD concentration was as high as 4224 mg/L. In addition, plenty of microorganisms, attached to the carriers and assumed to be the reason behind the organic biodegradation efficiency of the proposed system, were observed using scanning electron microscopy (SEM).

  12. Kinetics of thermal decomposition of hydrated minerals associated with hematite ore in a fluidized bed reactor

    Science.gov (United States)

    Beuria, P. C.; Biswal, S. K.; Mishra, B. K.; Roy, G. G.

    2017-03-01

    The kinetics of removal of loss on ignition (LOI) by thermal decomposition of hydrated minerals present in natural iron ores (i.e., kaolinite, gibbsite, and goethite) was investigated in a laboratory-scale vertical fluidized bed reactor (FBR) using isothermal methods of kinetic analysis. Experiments in the FBR in batch processes were carried out at different temperatures (300 to 1200°C) and residence time (1 to 30 min) for four different iron ore samples with various LOIs (2.34wt% to 9.83wt%). The operating velocity was maintained in the range from 1.2 to 1.4 times the minimum fluidization velocity ( U mf). We observed that, below a certain critical temperature, the FBR did not effectively reduce the LOI to a desired level even with increased residence time. The results of this study indicate that the LOI level could be reduced by 90% within 1 min of residence time at 1100°C. The kinetics for low-LOI samples (controlled physical moisture removal), followed by a higher activation energy (chemically controlled removal of LOI). In the case of high-LOI samples, three different kinetics mechanisms prevail at different temperature regimes. At temperature up to 450°C, diffusion kinetics prevails (removal of physical moisture); at temperature from 450 to 650°C, chemical kinetics dominates during removal of matrix moisture. At temperatures greater than 650°C, nucleation and growth begins to influence the rate of removal of LOI.

  13. CO{sub 2} capture from flue gases using three Ca-based sorbents in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.S.; Fang, F.; Cai, N.S. [Tsinghua University, Beijing (China). Dept. of Thermal Engineering

    2009-06-15

    Abstract: Experiments of CO{sub 2} capture and sorbent regeneration characteristics of limestone, dolomite, and CaO/Ca{sub 1}2Al{sub 14}O{sub 3}3 at high temperature were investigated in a thermogravimetric analyzer (TGA) and a fluidized bed reactor. The effect of reactivity decay of limestone, dolomite, and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents on CO{sub 2} capture and sorbent regeneration processes was studied. The experimental results indicated that the operation time of high efficient CO{sub 2} capture stage declined continuously with increasing of the cyclic number due to the loss of the sorbent activity, and the final CO{sub 2} capture efficiency would remain nearly constant, due to the sorbent already reaching the final residual capture capacity. After the CO{sub 2} capture step, the Ca-based sorbents need to be regenerated to be used for a subsequent cycle, and the multiple calcination processes of Ca-based sorbent under different calcination conditions are studied and discussed. Reactivity loss of limestone, dolomite and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents from a fluidized bed reactor at both mild and severe calcination conditions was compared with the TGA data. At mild calcination conditions, TGA results of sorbent reactivity loss were similar to the experimental results of fluidized bed reactor for three sorbents at 850 degrees C calcination temperature, and this indicated that TGA experimental results can be used as a reference to predict sorbent reactivity loss behavior in fluidized bed reactor. At severe calcination condition, sorbent reactivity loss behavior for limestone and dolomite from TGA compare well with the result from a fluidized bed reactor.

  14. Continuous Ethanol Production Using Immobilized-Cell/Enzyme Biocatalysts in Fluidized-Bed Bioreactor (FBR)

    Energy Technology Data Exchange (ETDEWEB)

    Nghiem, NP

    2003-11-16

    The immobilized-cell fluidized-bed bioreactor (FBR) was developed at Oak Ridge National Laboratory (ORNL). Previous studies at ORNL using immobilized Zymomonas mobilis in FBR at both laboratory and demonstration scale (4-in-ID by 20-ft-tall) have shown that the system was more than 50 times as productive as industrial benchmarks (batch and fed-batch free cell fermentations for ethanol production from glucose). Economic analysis showed that a continuous process employing the FBR technology to produce ethanol from corn-derived glucose would offer savings of three to six cents per gallon of ethanol compared to a typical batch process. The application of the FBR technology for ethanol production was extended to investigate more complex feedstocks, which included starch and lignocellulosic-derived mixed sugars. Economic analysis and mathematical modeling of the reactor were included in the investigation. This report summarizes the results of these extensive studies.

  15. 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}.

  16. Low temperature circulating fluidized bed gasification and co-gasification of municipal sewage sludge

    DEFF Research Database (Denmark)

    Thomsen, Tobias Pape; Hauggaard-Nielsen, Henrik; Gøbel, Benny

    2017-01-01

    The study is part 2 of 2 in an investigation of gasification and co-gasification of municipal sewage sludge in low temperature gasifiers. In this work, solid residuals from thermal gasification and co-gasification of municipal sewage sludge were investigated for their potential use as fertilizer....... Ashes from five different low temperature circulating fluidized bed (LT-CFB) gasification campaigns including two mono-sludge campaigns, two sludge/straw mixed fuels campaigns and a straw reference campaign were compared. Experiments were conducted on two different LT-CFBs with thermal capacities of 100...... in a pot experiment with the most promising ash material. Co-gasification of straw and sludge in LT-CFB gasifiers produced ashes with a high content of recalcitrant C, phosphorus (P) and potassium (K), a low content of heavy metals (especially cadmium) and an improved plant P availability compared...

  17. Kinetic vaporization of heavy metals during fluidized bed thermal treatment of municipal solid waste.

    Science.gov (United States)

    Yu, Jie; Sun, Lushi; Xiang, Jun; Hu, Song; Su, Sheng

    2013-02-01

    Heavy metals volatilization during thermal treatment of model solid waste was theoretically and experimentally investigated in a fluidized bed reactor. Lead, cadmium, zinc and copper, the most four conventional heavy metals were investigated. Particle temperature model and metal diffusion model were established to simulate the volatilization of CdCl(2) evaporation and investigate the possible influencing factors. The diffusion coefficient, porosity and particle size had significant effects on metal volatilization. The higher diffusion coefficient and porosity resulted in the higher metal evaporation. The influence of redox conditions, HCl, water and mineral matrice were also investigated experimentally. The metal volatilization can be promoted by the injection of HCl, while oxygen played a negative role. The diffusion process of heavy metals within particles also had a significant influence on kinetics of their vaporization. The interaction between heavy metals and mineral matter can decrease metal evaporation amount by forming stable metallic species. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Korcak, R.F.

    1980-01-01

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

  19. Computer simulation and parametric study of a Sasol type fluidized bed Fischer-Tropsch reactor

    Energy Technology Data Exchange (ETDEWEB)

    Visser, P.R.

    1979-01-01

    A computer program composed of a mass and energy balance for a Sasol type Fischer-Tropsch fluidized bed reactor is presented. A parametric study is performed using temperature, pressure, degree of hydrocarbon saturation and average hydrocarbon chain length as variables. Increasing temperature is found to decrease the amount of hydrocarbons formed. The results of variation of pressure confirmed a relationship exists between conversion, temperature and residence time. The effect on product distribution by varying the last two parameters is negligible. Relationships between reactor pressure and temperature and the hydrocarbon degree of saturation and average chain length exists, however, at this time only general trends are known. A summary of the thermodynamics and kinetics of the Fischer-Tropsch reaction is also presented.

  20. Biodegradation kinetics during different start up of the anaerobic tapered fluidized bed reactor

    Directory of Open Access Journals (Sweden)

    Rangasamy Parthiban

    2011-10-01

    Full Text Available Kinetic study for different start up conditions of the anaerobic digestion of wastewater derived from the sago processingfrom tubers of tapioca (Mannihot utillisema is discussed. The experiment is carried out with synthetic waste water usinga tapered fluidized bed reactor. Mesoporous granulated activated carbon is used as a bacterial support. The kinetic modelfollows half order kinetics for substrate utilization and for methane formation and it exhibits an order of 0.20 during thestart up of the reactor without acclimatization. For the remaining start up with acclimatized sludge, kinetic parameters areexpressed in terms of Langmuir-Hinshelwood kinetics for the substrate utilization. The methane formation kinetics followsan order of the reaction as 0.30. The values of the kinetic constants are in the range of 0.13–0.21.

  1. Flash Pyrolysis and Fractional Pyrolysis of Oleaginous Biomass in a Fluidized-bed Reactor

    Science.gov (United States)

    Urban, Brook

    Thermochemical conversion methods such as pyrolysis have the potential for converting diverse biomass feedstocks into liquid fuels. In particular, bio-oil yields can be maximized by implementing flash pyrolysis to facilitate rapid heat transfer to the solids along with short vapor residence times to minimize secondary degradation of bio-oils. This study first focused on the design and construction of a fluidized-bed flash pyrolysis reactor with a high-efficiency bio-oil recovery unit. Subsequently, the reactor was used to perform flash pyrolysis of soybean pellets to assess the thermochemical conversion of oleaginous biomass feedstocks. The fluidized bed reactor design included a novel feed input mechanism through suction created by flow of carrier gas through a venturi which prevented plugging problems that occur with a more conventional screw feeders. In addition, the uniquely designed batch pyrolysis unit comprised of two tubes of dissimilar diameters. The bottom section consisted of a 1" tube and was connected to a larger 3" tube placed vertically above. At the carrier gas flow rates used in these studies, the feed particles remained fluidized in the smaller diameter tube, but a reduction in carrier gas velocity in the larger diameter "disengagement chamber" prevented the escape of particles into the condensers. The outlet of the reactor was connected to two Allihn condensers followed by an innovative packed-bed dry ice condenser. Due to the high carrier gas flow rates in fluidized bed reactors, bio-oil vapors form dilute aerosols upon cooling which that are difficult to coalesce and recover by traditional heat exchange condensers. The dry ice condenser provided high surface area for inertial impaction of these aerosols and also allowed easy recovery of bio-oils after natural evaporation of the dry ice at the end of the experiments. Single step pyrolysis was performed between 250-610°C with a vapor residence time between 0.3-0.6s. At 550°C or higher, 70% of

  2. 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.

  3. Potential industrial applications for fluidized-bed waste heat recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Cox, D.; Lytton, M.; Rao, C.

    1979-12-01

    Information was developed on potential applications of Fluidized-Bed Waste Heat Recovery Systems (FWHRS) in US industries that will assist the DOE in their decision to plan and participate in a demonstration project of the FWHRS. The study included a review of the literature and personal contacts (via telephone) with industry personnel with the objective to identify a limited number of applications. Technical and economic assessments for specific applications were accomplished by developing generalized design, performance, and cost parameters that could be applied based on selected critical characteristics of each potential application of the FWHR system. Waste energy streams identified included flue gas and off-gas from boilers, furnaces, and kiln. Utilization of the waste energy recovered included electric power generation, preheating combustion air and boiler feedwater, and drying. A course of action is recommended to DOE regarding generic users for demonstration projects.

  4. Simulation of Roasting Metallurgical Concentrates in Fluidized Bed Using CFD-DEM

    Science.gov (United States)

    Beloglazov, I. I.; Kuskova, Y. V.

    2017-07-01

    In this study, we utilized multiphase computational fluid dynamics (CFD), and discrete element method (DEM). Effect of the kinetic parameters of the roasting process in a fluidized bed was investigated. Our results indicate that it is possible to numerically integrate the coupled CFD-DEM system without significantly increasing computational overhead. It is also clear, however, that reactor operating conditions, reaction kinetics, and multiphase flow dynamics have major impacts on the roasting products exiting the reactor. We find that, with the same pre-exponential factors and mean activation energies, inclusion of distributed activation energies in the kinetics can shift the predicted average value of the exit gas-solidphase and its statistical distribution, compared to single-valued activation-energy kinetics. These findings imply that accurate resolution of the reaction activation energy distributions will be important for optimizing roasting processes.

  5. 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.

  6. Measuring the Kinetics of the Reduction of Iron Oxide with Carbon Monoxide in a Fluidized Bed

    Science.gov (United States)

    Bohnt, C. D.; Cleeton, J. P.; Miiller, C. M.; Scotr, S. A.; Dennis, J. S.

    Combusting a solid fuel in the presence of a metal oxide rather than air, chemical looping combustion, generates CO2suitable for sequestration and the reduced metal. For the case of iron, the reduced oxide can be re-oxidized with steam to produce high-purity hydrogen. The reduction reactions of iron oxide in carbon monoxide and carbon dioxide mixtures were investigated in a fluidized bed. Activation energies and pre-exponential factors for the reactions (i) 3 Fe2O3+CO⇌2 Fe3O4+CO2 and⇌(ii)0.947 Fe3O4+0.788 CO⇌3 Fe0.947O+0.788 CO2⇌were determined. The reaction order was verified to be unity, and the change in rate with conversion was examined.

  7. Fabrication and properties of foam geopolymer using circulating fluidized bed combustion fly ash

    Science.gov (United States)

    Liu, Ze; Shao, Ning-ning; Wang, Dong-min; Qin, Jun-feng; Huang, Tian-yong; Song, Wei; Lin, Mu-xi; Yuan, Jin-sha; Wang, Zhen

    2014-01-01

    In recent years, circulating fluidized bed combustion fly ash (CFA) is used as a raw material for geopolymer synthesis. Hydrogen peroxide was employed as a foaming agent to prepare CFA-based foam geopolymer. The particle distribution, mineral composition, and chemical composition of CFA were examined firstly. Geopolymerization products were characterized by mechanical testing, scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). The CFA-based foam geopolymer was successfully fabricated with different contents of hydrogen peroxide and exhibited uncompleted alkali reaction and reasonable strength with relative low atomic ratios of Si/Al and Si/Na. Type-C CFA in this research could be recycled as an alternative source material for geopolymer production.

  8. Study on Reactivity of Circulating Fluidized Bed Combustion Fly Ashes in the Presence of Water

    Directory of Open Access Journals (Sweden)

    Salain I.M.A.K.

    2010-01-01

    Full Text Available A study on reactivity of four different Circulating Fluidized Bed Combustion (CFBC fly ashes has been realized in the presence of water. Paste of each ash was prepared and analyzed for its setting time, expansion and strength. The products of hydration, and their evolutions over a period of time were identified by X-ray diffraction and differential thermal analysis. The results of this study show that the reactivity of the CFBC fly ashes is strongly related to their chemical composition, essentially to their quantity of silica, alumina, lime and sulfate, which promote principally the formation of ettringite, gypsum and C-S-H. It is further noted that the intensity and the proportion of these phases determine the hydration behavior of the CFBC fly ashes.

  9. Fluidized bed combustion residue as an alternative liming material and Ca source. [Prunus persica

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, J.H.; Horton, B.D.; White, A.W. Jr.; Bennett, O.L.

    1985-01-01

    Fluidized bed combustion residue (FBCR), a by-product of fossil fuel fired boilers, was evaluated as a liming material and a source of calcium for peaches (Prunus persica (L.) Batsch). Incubation studies involving a medium textured soil indicated that FBCR (calcite (FBCRC) or dolomitic (FBCRD) sources) was as effective a liming amendment as the respective agricultural limestone. Maximum soil pH occurred after 26 days incubation with FBCRC, but soil pH increased continuously throughout 137 days incubation with dolomitic limestone. Ammonium acetate extractable Ca was not affected by calcitic source, but Mg concentration increased with rates with the two dolomitic sources, and was highest in the FBCRD source after 137 days incubation. In greenhouse studies with Elberta peach seedlings, FBCRC was more effective in neutralizing soil acidity and increasing extractable soil Ca than calcitic limestone.

  10. The growth and dissolution of sodium perborate crystals in a fluidized bed crystallizer

    Science.gov (United States)

    Chianese, A.; Condò, A.; Mazzarotta, B.

    1989-09-01

    The growth and dissolution rates of sodium perborate (SPB) crystals in aqueous solutions were measured by means of a fluidized bed apparatus. The influence on the overall growth rate of the concentration of sodium metaborate (SMB) in aqueous solutions, in the range 0-4.7 wt%, of the temperature, between 18 and 28° C, and of the crystal size, in the range 0.27-0.72 mm was investigated. By determining properly the surface-volume shape factor of the crystals, markedly dendritic, the independence of the overall growth rate on the crystal size results, whereas both the dissolution and growth phenomenon are greatly affected by the presence of SMB in solution.

  11. Effect of distributor on performance of a continuous fluidized bed dryer

    Science.gov (United States)

    Yogendrasasidhar, D.; Srinivas, G.; Pydi Setty, Y.

    2017-09-01

    Proper gas distribution is very important in fluidized bed drying in industrial practice. Improper distribution of gas may lead to non-idealities like channeling, short circuiting and accumulation which gives rise to non-uniform quality of dried product. Gas distribution depends on the distributor plate used. Gas distribution mainly depends on orifice diameter, number of orifices and opening area of the distributor plate. Small orifice diameter leads to clogging, and a large orifice diameter gives uneven distribution of gas. The present work involves experimental studies using different distributor plates and simulation studies using ASPEN PLUS steady state simulator. The effect of various parameters such as orifice diameter, number of orifices and the opening area of the distributor plate on the performance of fluidized bed dryer have been studied through simulation and experimentation. Simulations were carried out (i) with increasing air inlet temperature to study the characteristics of solid temperature and moisture in outlet (ii) with increasing orifice diameter and (iii) with increase in number orifices to study the solid outlet temperature profiles. It can be observed from the simulation that, an increase in orifice diameter and number orifices increases solid outlet temperature upto certain condition and then after there is no effect with further increase. Experiments were carried out with increasing opening area (3.4 to 42%) in the form of increasing orifice diameter keeping the number of orifices constant and increasing number of orifices of the distributor plate keeping the orifice diameter constant. It can be seen that the drying rate and solid outlet temperature increase upto certain condition and then after with further increase in the orifice diameter and number of orifices, the change in the drying rate and solid outlet temperature observed is little. The optimum values of orifice diameter and number of orifices from experimentation are found to be 5

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

    Energy Technology Data Exchange (ETDEWEB)

    Korcak, R.F.

    1980-01-01

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

  13. Fluidized bed material apples at disposal levels: effects on an apple orchard. [Malus domestica Borkh

    Energy Technology Data Exchange (ETDEWEB)

    Korcak, R.F.

    Atmospheric fluidized-bed combustion represents and economical technology for the burning of high S fossil fuel. The combustion residue is a dry, alkaline material resulting from the burning of coal (or other fuel source) and limestone. Although the residue has been assessed as a limestone substitute, the current study examines the potential for disposing of relatively large quantities. Fluidized bed material (FBM) was applied at two rates to the surface area within the rows of an established apple (Malus domestica Borkh.) orchard containing four tree types. The rates were either 9.2 kg/m/sup 2/ (low rate), 36 kg/m/sup 2/ (high rate), or untreated control. The tree types used were Spuree Rome on M9, Redchief Delicious on M9 or M9/MM106, and Sturdeespur Delicious on M9. Cumulative yields (kg/tree) were enhanced on three of four tree types over a period of 6 yr. A 15% reduction in yield was noted for Redchief Delicious on M9/MM106 stocks at the high FBM rate. No nutritional related problems were noted for this or any other of the tree types used. Part of the yield reduction noted was due to fruit size differences and/or differential sensitivity of this interstock/rootstock combination to the altered soil chemical properties. Generally, amended soil pH increased to about 7.0 for either rate, and electrical conductivity increased five fold at the high rate of FBM addition. Agricultural utilization of large volume (up to 112 Mg/ha) of FBM, compared to past research where FBM was used as a lime substitute (2-6 mg/ha), appears to be a feasible alternative. However, rootstock selection for apple may need to consider the resultant changes in soil chemical status from FBM additions.

  14. Effects of microwave - fluidized bed drying on quality, energy consumption and drying kinetics of soybean kernels.

    Science.gov (United States)

    Khoshtaghaza, Mohammad Hadi; Darvishi, Hosain; Minaei, Saeid

    2015-08-01

    Moisture content of soybean kernel at harvest time is too high for storage, and needs to be reduced. In this research, drying characteristics, quality and energy requirement for microwave-fluidized bed drying of soybean kernels were studied. The results showed that air temperature (80-140 °C), velocity (1.8-4.5 m/s) and microwave power (200-500 W) significantly influenced drying time, moisture diffusivity, rehydration capacity, cracking, and specific energy consumption (P ≤ 0.05). Among the applied models, Page's model has the best performance to estimate the microwave-fluidized bed drying behavior of the soybean kernels. Moisture diffusivity values increased (6.25 × 10(-10) to 42.14 × 10(-10) m(2)/s) as the air velocity decreased and air temperature and microwave power increased. Activation energy was foundto be between 3.33 and 17.70 kJ/mol. Minimum cracking percentage of soybean kernels (12.96 %) was obtained at 80 °C, 1.8 m/s and 200 W treatments. The increase in microwave power and decrease in air velocity level decreased the rehydration capacity. Specific energy consumption varied from 50.94 to 338.76 MJ/kg water and the lowest specific energy consumption were obtained at 80 °C, 4.5 m/s and 500 W.

  15. Combustion of bark and wood waste in the fluidized bed boiler

    Science.gov (United States)

    Pleshanov, K. A.; Ionkin, I. L.; Roslyakov, P. V.; Maslov, R. S.; Ragutkin, A. V.; Kondrat'eva, O. E.

    2016-11-01

    In the Energy Development Strategy of Russia for the Period until 2035, special attention is paid to increased use of local fuel kinds—one of which is biofuel, in particular, bark and wood waste (BWW)— whose application at thermal power plants in Russia has been not developed due to the lack of appropriate technologies mastered by domestic energy mechanical engineering. The article describes the experience of BWW combustion in fluidized bed boilers installed on the energy objects of northern European countries. Based on this, reference points were defined (it is the section of boiler air-gas path where initially the approximate temperatures are set), making it possible to carry out a thermal design of a boiler and ensure its operation reliability. Permissible gas temperature at the furnace outlet at BWW combustion amounted to 950-1000°C. Exit gas temperature, depending on the implementation of special measures on protection of air heater from corrosion, amounted to 140-190°C. Recommended hot air temperature is within the range of 200-250°C. Recommendations for determining the boiler furnace dimensions are presented. Based on the presented reference temperatures in the main reference points, the thermal design of hot water boiler of KV-F-116-150 type with 116 MW capacity was carried out. The analysis of the results and comparison of designed boiler characteristics with operating energy boilers, in which a fuel is burned in a fluidized bed, were carried out. It is shown that, with increasing the boiler capacity, the ratio of its heating power Q to the crosssectional area of furnace chamber F rises. For power-generating boiler of thermal capacity of 100 MW, the ratio is within 1.8-2.2MW/m2. The boiler efficiency exceeds 90% in the range of changes of exit gas temperature typical for such equipment.

  16. Fast determination of trace dimethyl fumarate in milk with near infrared spectroscopy following fluidized bed enrichment.

    Science.gov (United States)

    Xie, Ya-Jie; Wang, Zhuan; Hu, Wan-Peng; Xu, Song

    2012-12-01

    Near infrared spectroscopy (NIRS) has been proved to be a powerful analytical tool in different fields. However, because of the low sensitivity in near infrared region, it is a significant challenge to detect trace analytes with normal NIRS technique. A novel enrichment technique called fluidized bed enrichment has been developed recently to improve sensitivity of NIRS which allows a large volume solution to pass through within a short time. In this paper, fluidized bed enrichment method was applied in the determination of trace dimethyl fumarate in milk. Macroporous styrene resin HZ-816 was used as adsorbent material, and 1 L solution of dimethyl fumarate was run to pass through the material for concentration. The milk sample was pretreated to remove interference matters such as protein, fat, and then passed through the material for enrichment; after that, diffuse reflection NIR spectra were measured for the analyte concentrated on the material directly without any elution process. The enrichment and spectral measurement procedures were easy to operate. NIR spectra in 900-1,700 nm were collected for dimethyl fumarate solutions in the concentration range of 0.506-5.060 μg/mL and then used for multivariate calibration with partial least squares (PLS) regression. Spectral pretreatment methods such as multiplicative scatter correction, first derivative, second derivative, and their combinations were carried out to select the optimal PLS model. Root mean square error of cross-validation calculated by leave-one-out cross-validation is 0.430 μg/mL with ten PLS factors. Ten samples in an independent test set were predicted by the model with the mean relative error of 5.33%. From the results shown in this work, it can be concluded that the NIR technique coupled with on-line enrichment method can be expanded for the determination of trace analytes, and its applications in real liquid samples like milk and juice may also be feasible.

  17. Biomass gasification in a circulating fluidized bed; Vergasung von Biomasse in der zirkulierenden Wirbelschicht

    Energy Technology Data Exchange (ETDEWEB)

    Ising, M.; Hoelder, D.; Backhaus, C.; Althaus, W. [Fraunhofer Inst. fuer Umwelt-, Sicherheits- und Energietechnik UMSICHT, Oberhausen (Germany)

    1998-09-01

    Biomass gasification in a circulating fluidized bed, in combination with a gas engine or gas burner, is a promising option for energetic use of biomass. Economic efficiency analyses on the basis of the UMSICHT plant show that this technology for combined heat and power generation from biomass is promising also for the range below 10 MW. The economic situation of any plant must be considered for the specific boundary conditions imposed by the power supply industry. The feasibility of the process was tested in a demonstration plant at Oberhausen. The plant was optimized further in extensive test series, and a number of tar reduction processes were investigated and improved on. The authors now intend to prove that gasification in a circulating fluidized bed combined with a gas engine cogeneration plant is feasible in continuous operation. (orig./SR) [Deutsch] Die Vergasung von Biomasse in der zirkulierenden Wirbelschicht ist in Kombination mit einem Gasmotor oder einem Gasbrenner eine vielversprechende Option fuer die energetische Biomassenutzung. Wirtschaftlichkeitsbetrachtungen auf Basis der UMSICHT-Anlage zeigen, dass diese Technologie fuer die gekoppelte Strom- und Waermeerzeugung aus Biomasse auch im Leistungsbereich unter 10 MW grosse Chancen verspricht. Dabei ist die oekonomische Situation einer Anlage im Einzelfall unter Beachtung der energiewirtschaftlichen Randbedingungen zu beurteilen. Durch den Betrieb einer Demonstrationsanlage in Oberhausen konnte die Funktion des Verfahrens nachgewiesen werden. In weiteren umfangreichen Versuchsreihen werden die Anlage weiter optimiert und verschiedene Konzepte zur Teerminderung untersucht und weiterentwickelt. Angestrebt ist der Nachweis des Dauerbetriebs von ZWS-Vergasung zusammen mit dem Gasmotoren-BHKW. (orig./SR)

  18. An innovative example of herb residues recycling by gasification in a fluidized bed.

    Science.gov (United States)

    Guo, Feiqiang; Dong, Yuping; Dong, Lei; Jing, Yuanzhuo

    2013-04-01

    A utilization way of herb residues is designed to convert herb residues to gas fuel in industrial-scale by a circulating fluidized bed gasifier in this paper. The product gas is used in the production of Chinese medicine, and the heat of the flue gas from the boiler can be used in herb residues drying to realize the energy recycling and no herb residues discharge. The gasification characteristics of herb residues in the circulating fluidized bed of 300 kg/h were investigated for about 200 h. The results indicated that the gas composition and tar yield were affected by biomass flow rate, equivalence ratio (ER), moisture content and char circulating. The lower heating value of product gas was 4-5 MJ/m(3) using herb residues as feedstock. When mean biomass flow rate was at 5.5 kg m(-2)s(-1) and ER at 0.35, the product gas reached a good condition with lower heating value of 4.89 MJ/m(3) and cold gas efficiency of 62.36%. When the moisture content changed from 12.5% to 18.7%, the concentrations of H2, CO and CO2 changed from 4.66% to 6.92%, 11.23% to 10.15%, and 16.55% to 17.82% respectively, and the tar content in gas decreased from 15.1g/m(3) to 14.4 g/m(3) when the moisture content increased from 12.5% to 15.4%. There are metal oxides in the ash of herb residues, especially CaO, MgO, K2O, Al2O3, and Fe2O3 which have obvious function on tar catalytic decomposition. The ash that attaches to the char particles can decrease the tar yield and improve the quality of gas after returning to the gasifier. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Performance of dye-affinity beads for aluminium removal in magnetically stabilized fluidized bed

    Science.gov (United States)

    Yavuz, Handan; Say, Ridvan; Andaç, Müge; Bayraktar, Necmi; Denizli, Adil

    2004-01-01

    Background Aluminum has recently been recognized as a causative agent in dialysis encephalopathy, osteodystrophy, and microcytic anemia occurring in patients with chronic renal failure who undergo long-term hemodialysis. Only a small amount of Al(III) in dialysis solutions may give rise to these disorders. Methods Magnetic poly(2-hydroxyethyl methacrylate) (mPHEMA) beads in the size range of 80–120 μm were produced by free radical co-polymerization of HEMA and ethylene dimethacrylate (EDMA) in the presence of magnetite particles (Fe3O4). Then, metal complexing ligand alizarin yellow was covalently attached onto mPHEMA beads. Alizarin yellow loading was 208 μmol/g. These beads were used for the removal of Al(III) ions from tap and dialysis water in a magnetically stabilized fluidized bed. Results Al(III) adsorption capacity of the beads decreased with an increase in the flow-rate. The maximum Al(III) adsorption was observed at pH 5.0. Comparison of batch and magnetically stabilized fluidized bed (MSFB) maximum capacities determined using Langmuir isotherms showed that dynamic capacity (17.5 mg/g) was somewhat higher than the batch capacity (11.8 mg/g). The dissociation constants for Al(III) were determined using the Langmuir isotherm equation to be 27.3 mM (MSFB) and 6.7 mM (batch system), indicating medium affinity, which was typical for pseudospecific affinity ligands. Al(III) ions could be repeatedly adsorbed and desorbed with these beads without noticeable loss in their Al(III) adsorption capacity. Conclusions Adsorption of Al(III) demonstrate the affinity of magnetic dye-affinity beads. The MSFB experiments allowed us to conclude that this inexpensive sorbent system may be an important alternative to the existing adsorbents in the removal of aluminium. PMID:15329149

  20. Experimental and Numerical Investigation of Four- Phase Flow (Water–Gasoline-Air-Solid in a Fluidized Bed Column

    Directory of Open Access Journals (Sweden)

    Riyadh S. Al-Turaihi

    2016-03-01

    Full Text Available In this paper four phase fluidized bed is experimentally built and numerically modeled to study the bed characteristics such as ratio (the static bed height of solid particle / the bed diameter (H/D, air, gasoline , and water superficial velocity. The test pipe for the experimental rig is Perspex pipe with 1 m long and 0.0254 m diameter. The 2D numerical model has been established with Ansys fluent 15.0. Pressure drop equation is found to relate the pressure drop with the bed parameters with deviation of 22%. The Four-phases was represented by air, water, gasoline and solid particle. The results show that the pressure of the bed increases as the ratio H/D increases and air, gasoline , and water superficial velocity increases. As well as the expansion of the bed increases as air, gasoline, and water superficial velocity increases.

  1. About the gasification of untreated scrap and waste wood in fluidized bed reactor for use in decentralized gas engine-cogeneration plants; Zur Vergasung von Rest- und Abfallholz in Wirbelschichtreaktoren fuer dezentrale Energieversorgungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Tepper, H.

    2005-10-20

    This dissertation examines the thermochemical conversion (gasification) of untreated scrap and waste wood in combustible gases for use in decentralized gas engine-cogeneration plants of low output (1 to 10 MW fuel power). A general section goes into the basics of the energetic utilization of solid biomass, the subprocesses of thermochemical conversion being described in more detail. Special attention is given to the processes and state of the art of biomass gasification in decentralized plants. A theoretical section analyzes the gasification models for solid biomass presented in the literature. Based on this analysis, a simplified kinetic model is derived for the gasification of untreated scrap and waste wood with air in bubbling fluidized bed reactors. It includes a fluid mechanic analysis of the fluidized bed based on HILLIGARDT, an empirical pyrolysis model and a global kinetic approach to the main chemical reaction taken from the literature. An experimental section describes the tests of the gasification of forest scrap wood in a semi-industrial fluidized bed gasification test plant with 150 kW fuel power and presents the significant test results. The gasification model derived is applied to check the test plant's standard settings and compare them with measured values. Furthermore, the model is employed to explain basic reaction paths and zones and to perform concluding parameter simulations. (orig.)

  2. Simulations of flow behavior of fuel particles in a conceptual helium-cooled spout fluidized bed nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shuyan; Li Xiang [School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Lu Huilin [School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)], E-mail: huilin@hit.edu.cn; Bouillard, Jacques [INERIS, Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Sun Qiaoqun; Wang Shuai [School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2009-01-15

    Hydrodynamics of helium and fuel particles are simulated in a conceptual helium-cooled spout fluidized bed nuclear reactor. The conceptual reactor consists of an axis-symmetric column with a sharp cone inside which the fuel particles are fluidized by helium. An isothermal gas-solid two-fluid flow model is presented. The kinetic-frictional constitutive model for dense assemblies of solids is incorporated. The kinetic stress is modeled using the kinetic theory of granular flow, while the friction stress is from the normal frictional stress model proposed by (Johnson, P.C., Nott, P., Jackson, R., 1990. Frictional-collisional equations of motion for particulate flows and their application to chutes. Journal of Fluid Mechanics 210, 501-535). Detailed spatial/temporal concentration and velocity profiles have been obtained in a conceptual spout fluidized bed nuclear reactor. The influence of inlet spouting jet velocity and conical angles on flow behavior of fluid and fuel particles is analyzed. The numerical simulations show that the unique mixing ability of the spout fluidized bed nuclear reactor gives rise, as expected, to uniform particle distributions. This uniformity enhances the heat transfer and therefore the power produced by the reactor.

  3. Fluidized Bed Steam Reforming of Hanford LAW Using THORsm Mineralizing Technology

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Arlin L.; Nicholas R Soelberg; Douglas W. Marshall; Gary L. Anderson

    2004-11-01

    The U.S. Department of Energy (DOE) documented, in 2002, a plan for accelerating cleanup of the Hanford Site, located in southeastern Washington State, by at least 35 years. A key element of the plan was acceleration of the tank waste program and completion of ''tank waste treatment by 2028 by increasing the capacity of the planned Waste Treatment Plant (WTP) and using supplemental technologies for waste treatment and immobilization.'' The plan identified steam reforming technology as a candidate for supplemental treatment of as much as 70% of the low-activity waste (LAW). Mineralizing steam reforming technology, offered by THOR Treatment Technologies, LLC would produce a denitrated, granular mineral waste form using a high-temperature fluidized bed process. A pilot scale demonstration of the technology was completed in a 15-cm-diameter reactor vessel. The pilot scale facility was equipped with a highly efficient cyclone separator and heated sintered metal filters for particulate removal, a thermal oxidizer for reduced gas species and NOx destruction, and a packed activated carbon bed for residual volatile species capture. The pilot scale equipment is owned by the DOE, but located at the Science and Technology Applications Research (STAR) Center in Idaho Falls, ID. Pilot scale testing was performed August 2–5, 2004. Flowsheet chemistry and operational parameters were defined through a collaborative effort involving Idaho National Engineering and Environmental Laboratory, Savannah River National Laboratory (SRNL), and THOR Treatment Technologies personnel. Science Application International Corporation, owners of the STAR Center, personnel performed actual pilot scale operation. The pilot scale test achieved a total of 68.7 hrs of cumulative/continuous processing operation before termination in response to a bed de-fluidization condition. 178 kg of LAW surrogate were processed that resulted in 148 kg of solid product, a mass reduction of about 17%. The process

  4. Fluidized bed combustion of pelletized biomass and waste-derived fuels

    Energy Technology Data Exchange (ETDEWEB)

    Chirone, R.; Scala, F.; Solimene, R. [Istituto di Ricerche sulla Combustione - C.N.R., Piazzale V. Tecchio 80, 80125 Naples (Italy); Salatino, P.; Urciuolo, M. [Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale V. Tecchio 80, 80125 Naples (Italy)

    2008-10-15

    The fluidized bed combustion of three pelletized biogenic fuels (sewage sludge, wood, and straw) has been investigated with a combination of experimental techniques. The fuels have been characterized from the standpoints of patterns and rates of fuel devolatilization and char burnout, extent of attrition and fragmentation, and their relevance to the fuel particle size distribution and the amount and size distribution of primary ash particles. Results highlight differences and similarities among the three fuels tested. The fuels were all characterized by limited primary fragmentation and relatively long devolatilization times, as compared with the time scale of particle dispersion away from the fuel feeding ports in practical FBC. Both features are favorable to effective lateral distribution of volatile matter across the combustor cross section. The three fuels exhibited distinctively different char conversion patterns. The high-ash pelletized sludge burned according to the shrinking core conversion pattern with negligible occurrence of secondary fragmentation. The low-ash pelletized wood burned according to the shrinking particle conversion pattern with extensive occurrence of secondary fragmentation. The medium-ash pelletized straw yielded char particles with a hollow structure, resembling big cenospheres, characterized by a coherent inorganic outer layer strong enough to prevent particle fragmentation. Inert bed particles were permanently attached to the hollow pellets as they were incorporated into ash melts. Carbon elutriation rates were very small for all the fuels tested. For pelletized sludge and straw, this was mostly due to the shielding effect of the coherent ash skeleton. For the wood pellet, carbon attrition was extensive, but was largely counterbalanced by effective afterburning due to the large intrinsic reactivity of attrited char fines. The impact of carbon attrition on combustion efficiency was negligible for all the fuels tested. The size

  5. Evaluation of the Hanford 200 West Groundwater Treatment System: Fluidized Bed Bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Looney, Brian B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jackson, Dennis G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dickson, John O. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Eddy-Dilek, Carol A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-05-12

    A fluidized bed reactor (FBR) in the 200W water treatment facility at Hanford is removing nitrate from groundwater as part of the overall pump-treat-reinject process. Control of the FBR bed solids has proven challenging, impacting equipment, increasing operations and maintenance (O&M), and limiting the throughput of the facility. In response to the operational challenges, the Department of Energy Richland Office (DOE-RL) commissioned a technical assistance team to facilitate a system engineering evaluation and provide focused support recommendations to the Hanford Team. The DOE Environmental Management (EM) technical assistance process is structured to identify and triage technologies and strategies that address the target problem(s). The process encourages brainstorming and dialog and allows rapid identification and prioritization of possible options. Recognizing that continuous operation of a large-scale FBR is complex, requiring careful attention to system monitoring data and changing conditions, the technical assistance process focused on explicit identification of the available control parameters (“knobs”), how these parameters interact and impact the FBR system, and how these can be adjusted under different scenarios to achieve operational goals. The technical assistance triage process was performed in collaboration with the Hanford team.

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

    Science.gov (United States)

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

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

  7. Support studies in fluidized-bed combustion. Annual report, July 1977-September 1978

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, I.; Vogel, G.J.; Lee, S.H.D.

    1979-01-01

    These laboratory and process development-scale studies support the Fossil Energy development program for atmospheric and pressurized fluidized-bed coal combustion. This report presents information on the enhancement of limestone sulfation by the use of chemical additives, the evaluation of coal char as fuel for FBCs, the use of oil shale in place of limestone for SO/sub 2/ emission control, development of a model for the prediction of the performance of limestones in FBCs from laboratory data, studies of the emission of alkali metal compounds from coal combustion systems, development of sorbents for the removal of gaseous KCl and NaCl from hot gas streams, studies of the fate of trace elements in a FBC combustion-regeneration system, evaluation of two laser instruments for the in situ measurement of particle size and concentration in a hot gas stream, evaluation of a high efficiency cyclone, the development of a granular bed filter for particulate removal, the development of a high-intensity sound source to enhance particulate agglomeration, and the development of a pulsed L-valve for the metering of the flow of solids.

  8. Data summary of municipal solid waste management alternatives. Volume 5, Appendix C, Fluidized-bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    None

    1992-10-01

    This appendix provides information on fluidized-bed combustion (FBC) technology as it has been applied to municipal waste combustion (MWC). A review of the literature was conducted to determine: (1) to what extent FBC technology has been applied to MWC, in terms of number and size of units was well as technology configuration; (2) the operating history of facilities employing FBC technology; and (3) the cost of these facilities as compared to conventional MSW installations. Where available in the literature, data on operating and performance characteristics are presented. Tabular comparisons of facility operating/cost data and emissions data have been complied and are presented. The literature review shows that FBC technology shows considerable promise in terms of providing improvements over conventional technology in areas such as NOx and acid gas control, and ash leachability. In addition, the most likely configuration to be applied to the first large scale FBC dedicated to municipal solid waste (MSW) will employ circulating bed (CFB) technology. Projected capital costs for the Robbins, Illinois 1600 ton per day CFB-based waste-to-energy facility are competitive with conventional systems, in the range of $125,000 per ton per day of MSW receiving capacity.

  9. Atmospheric fluidized bed gasification of promising biomass fuels in southern European regions

    Directory of Open Access Journals (Sweden)

    Panopoulos Kyriakos D.

    2007-01-01

    Full Text Available Three promising biomass fuels from southern European regions were gasified atmospherically with air in a lab-scale fluidized bed reactor with quartz or olivine as bed material. The fuels used were an agro-industrial residue (olive bagasse and the energy crops giant reed and sweet sorghum bagasse. Varying air ratios and temperatures were tested to study the impact on the product gas composition and tar load. Tars were higher in the case of olive bagasse, attributed to its higher lignin content compared to the other two biomasses with higher cellulose. Giant reed gasification causes agglomeration and defluidisation problems at 790°C while olive bagasse shows the least agglomeration tendency. The particular olivine material promoted the destruction of tars, but to a lesser level than other reported works; this was attributed to its limited iron content. It also promoted the H2 and CO2 production while CO content decreased. Methane yield was slightly affected (decreased with olivine, higher temperatures, and air ratios. Air ratio increase decreased the tar load but at the same time the gas quality deteriorated. .

  10. Waste-gasification efficiency of a two-stage fluidized-bed gasification system.

    Science.gov (United States)

    Liu, Zhen-Shu; Lin, Chiou-Liang; Chang, Tsung-Jen; Weng, Wang-Chang

    2016-02-01

    This study employed a two-stage fluidized-bed gasifier as a gasification reactor and two additives (CaO and activated carbon) as the Stage-II bed material to investigate the effects of the operating temperature (700°C, 800°C, and 900°C) on the syngas composition, total gas yield, and gas-heating value during simulated waste gasification. The results showed that when the operating temperature increased from 700 to 900°C, the molar percentage of H2 in the syngas produced by the two-stage gasification process increased from 19.4 to 29.7mol% and that the total gas yield and gas-heating value also increased. When CaO was used as the additive, the molar percentage of CO2 in the syngas decreased, and the molar percentage of H2 increased. When activated carbon was used, the molar percentage of CH4 in the syngas increased, and the total gas yield and gas-heating value increased. Overall, CaO had better effects on the production of H2, whereas activated carbon clearly enhanced the total gas yield and gas-heating value. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  11. Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor.

    Science.gov (United States)

    Rahaman, Md Saifur; Mavinic, Donald S; Meikleham, Alexandra; Ellis, Naoko

    2014-03-15

    The cost associated with the disposal of phosphate-rich sludge, the stringent regulations to limit phosphate discharge into aquatic environments, and resource shortages resulting from limited phosphorus rock reserves, have diverted attention to phosphorus recovery in the form of struvite (MAP: MgNH4PO4·6H2O) crystals, which can essentially be used as a slow release fertilizer. Fluidized-bed crystallization is one of the most efficient unit processes used in struvite crystallization from wastewater. In this study, a comprehensive mathematical model, incorporating solution thermodynamics, struvite precipitation kinetics and reactor hydrodynamics, was developed to illustrate phosphorus depletion through struvite crystal growth in a continuous, fluidized-bed crystallizer. A thermodynamic equilibrium model for struvite precipitation was linked to the fluidized-bed reactor model. While the equilibrium model provided information on supersaturation generation, the reactor model captured the dynamic behavior of the crystal growth processes, as well as the effect of the reactor hydrodynamics on the overall process performance. The model was then used for performance evaluation of the reactor, in terms of removal efficiencies of struvite constituent species (Mg, NH4 and PO4), and the average product crystal sizes. The model also determined the variation of species concentration of struvite within the crystal bed height. The species concentrations at two extreme ends (inlet and outlet) were used to evaluate the reactor performance. The model predictions provided a reasonably good fit with the experimental results for PO4-P, NH4-N and Mg removals. Predicated average crystal sizes also matched fairly well with the experimental observations. Therefore, this model can be used as a tool for performance evaluation and process optimization of struvite crystallization in a fluidized-bed reactor. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

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

  13. 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.

  14. Dynamic behavior and control requirements of an atmospheric fluidized-bed coal combustion power plant: A conceptual study

    Energy Technology Data Exchange (ETDEWEB)

    Smith, O.L.

    1987-06-01

    A first-principles model of a nominal 20-MW atmospheric-pressure fluidized-bed coal combustion (AFBC) power plant was developed to provide insight into fundamental dynamic behavior of fluidized-bed systems. The control system included major loops for firing rate, steam pressure and temperature, forced and induced draft air flow, SO/sub 2/ emission, drum water level, evaporator recirculation, and bed level. The model was used to investigate system sensitivity to design features such as the distribution of heat transfer surface among the bed boiler and superheater and the out-of-bed superheater. Also calculated were the sensitivities of temperatures, pressures, and flow rates to changes in throttle, attemperator, and feedwater valve settings and forced and induced draft damper settings. The large bed mass, accounting for approx.40% of the active heat capacity, may vary under load change and could impact controller tuning. Model analysis indicated, however, that for the design studied, the change in bed mass does not appear to significantly affect controller tuning even if the bed mass varies appreciably under load-following conditions. Several bed designs are being considered for AFBC plants, some with partitions between bed sections and some without, and these differences may significantly affect the load-following capability of the plant. The results indicated that the slumping mode of operation can cause distortion of the heat source/sink distribution in the bed such that the load-following capability (rate of load change) of the plant may be reduced by as much as a factor of 5 compared with the mode in which tube surface is exposed. 9 refs., 13 figs., 6 tabs.

  15. Experiment and modeling of CO{sub 2} capture from flue gases at high temperature in a fluidized bed reactor with Ca-based sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Fan Fang; Zhen-Shan Li; Ning-Sheng Cai [Tsinghua University, Beijing (China). Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education (MOE)

    2009-01-15

    The cyclic CO{sub 2} capture and CaCO{sub 3} regeneration characteristics in a small fluidized bed reactor were experimentally investigated with limestone and dolomite sorbents. Kinetic rate constants for carbonation and calcination were determined using thermogravimetric analysis (TGA) data. Mathematical models developed to model the Ca-based sorbent multiple cycles of CO{sub 2} capture and calcination in the bubbling fluidized bed reactor agreed with the experimental data. The experimental and simulated results showed that the CO{sub 2} in flue gases could be absorbed efficiently by limestone and dolomite. The time for high-efficiency CO{sub 2} capture decreased with an increasing number of cycles because of the loss of sorbent activity, and the final CO{sub 2} capture efficiency remained nearly constant as the sorbent reached its final residual capture capacity. In a continuous carbonation and calcination system, corresponding to the sorbent activity loss, the carbonation kinetic rates of sorbent undergoing various cycles are different, and the carbonation kinetic rates of sorbent circulating N times in the carbonation/calcination cycles are also different because of the different residence time of sorbent in the carbonator. Therefore, the average carbonation rate was given based on the mass balance and exit age distribution for sorbent in the carbonator. The CO{sub 2} capture characteristics in a continuous carbonation/calcination system were predicted, taking into consideration the mass balance, sorbent circulation rate, sorbent activity loss, and average carbonation kinetic rate, to give useful information for the reactor design and operation of multiple carbonation/calcination reaction cycles. 27 refs., 15 figs., 1 tab.

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

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C

    2008-07-31

    The purpose of crucible scale testing with actual radioactive Tank 48H material was to duplicate the test results that had been previously performed on simulant Tank 48H material. The earlier crucible scale testing using simulants was successful in demonstrating that bench scale crucible tests produce results that are indicative of actual Fluidized Bed Steam Reforming (FBSR) pilot scale tests. Thus, comparison of the results using radioactive Tank 48H feed to those reported earlier with simulants would then provide proof that the radioactive tank waste behaves in a similar manner to the simulant. Demonstration of similar behavior for the actual radioactive Tank 48H slurry to the simulant is important as a preliminary or preparation step for the more complex bench-scale steam reformer unit that is planned for radioactive application in the Savannah River National Laboratory (SRNL) Shielded Cells Facility (SCF) later in 2008. The goals of this crucible-scale testing were to show 99% destruction of tetraphenylborate and to demonstrate that the final solid product produced is sodium carbonate. Testing protocol was repeated using the specifications of earlier simulant crucible scale testing, that is sealed high purity alumina crucibles containing a pre-carbonated and evaporated Tank 48H material. Sealing of the crucibles was accomplished by using an inorganic 'nepheline' sealant. The sealed crucibles were heat-treated at 650 C under constant argon flow to inert the system. Final product REDOX measurements were performed to establish the REDuction/OXidation (REDOX) state of known amounts of added iron species in the final product. These REDOX measurements confirm the processing conditions (pyrolysis occurring at low oxygen fugacity) of the sealed crucible environment which is the environment actually achieved in the fluidized bed steam reformer process. Solid product dissolution in water was used to measure soluble cations and anions, and to investigate

  17. Single Crystal Casting with Fluidized Carbon Bed Cooling: A Process Innovation for Quality Improvement and Cost Reduction

    Science.gov (United States)

    Hofmeister, M.; Franke, M. M.; Koerner, C.; Singer, R. F.

    2017-12-01

    Superalloy gas turbine blades are being produced by investment casting and directional solidification. A new process, Fluidized Carbon Bed Cooling (FCBC), has been developed and is now being optimized in a prototype casting unit with 10 kg pouring weight. In early test runs with still rather simple mold cluster geometries, a reduction of the primary dendrite arm spacing of around 40 pct compared to the standard radiation cooling process (HRS) could be demonstrated. The improvement is mainly attributed to higher temperature gradients driving solidification, made possible by a functioning Dynamic Baffle. Compared to earlier development efforts in the literature, contamination of the melt and damage to the equipment are avoided using carbon-based fluidized bed materials and the so-called "counter pressure concept."

  18. Single Crystal Casting with Fluidized Carbon Bed Cooling: A Process Innovation for Quality Improvement and Cost Reduction

    Science.gov (United States)

    Hofmeister, M.; Franke, M. M.; Koerner, C.; Singer, R. F.

    2017-10-01

    Superalloy gas turbine blades are being produced by investment casting and directional solidification. A new process, Fluidized Carbon Bed Cooling (FCBC), has been developed and is now being optimized in a prototype casting unit with 10 kg pouring weight. In early test runs with still rather simple mold cluster geometries, a reduction of the primary dendrite arm spacing of around 40 pct compared to the standard radiation cooling process (HRS) could be demonstrated. The improvement is mainly attributed to higher temperature gradients driving solidification, made possible by a functioning Dynamic Baffle. Compared to earlier development efforts in the literature, contamination of the melt and damage to the equipment are avoided using carbon-based fluidized bed materials and the so-called "counter pressure concept."

  19. Bisphenol A removal by a Pseudomonas aeruginosa immobilized on granular activated carbon and operating in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mita, Luigi [National Laboratory on Endocrine Disruptors, National Institute of Biostructures and Biosystems (INBB), Via P. Castellino, 111, 80131 Naples (Italy); Institute of Genetic and Biophysics “ABT”, Via P. Castellino, 111, 80131 Naples Italy (Italy); Grumiro, Laura [National Laboratory on Endocrine Disruptors, National Institute of Biostructures and Biosystems (INBB), Via P. Castellino, 111, 80131 Naples (Italy); Rossi, Sergio [Institute of Genetic and Biophysics “ABT”, Via P. Castellino, 111, 80131 Naples Italy (Italy); Bianco, Carmen; Defez, Roberto [Institute of Biosciences and BioResources, Via P. Castellino, 111, 80131 Naples (Italy); Gallo, Pasquale [Dipartimento di Chimica, Istituto Zooprofilattico Sperimentale del Mezzogiorno, Via della Salute 2, 80055 Portici, Naples (Italy); Mita, Damiano Gustavo, E-mail: mita@igb.cnr.it [National Laboratory on Endocrine Disruptors, National Institute of Biostructures and Biosystems (INBB), Via P. Castellino, 111, 80131 Naples (Italy); Institute of Genetic and Biophysics “ABT”, Via P. Castellino, 111, 80131 Naples Italy (Italy); Diano, Nadia [National Laboratory on Endocrine Disruptors, National Institute of Biostructures and Biosystems (INBB), Via P. Castellino, 111, 80131 Naples (Italy); Department of Experimental Medicine, Second University of Naples, Via S.M. di Costantinopoli, 16, 80138 Naples Italy (Italy)

    2015-06-30

    Highlights: • A fluidized bed reactor, filled with a Pseudomonas aeruginosa immobilized on GAC, has been used for BPA removal. • BPA removal resulted from a biological activated carbon (BAC) process. • Equations describing the results have been indicated. • BPA removal was analyzed as a function of time and biofilm reuse. - Abstract: Serratia rubidiae, Pseudomonas aeruginosa and Escherichia coli K12 have been studied for their ability of Bisphenol A removal from aqueous systems and biofilm formation on activated granule carbon. Mathematical equations for biodegradation process have been elaborated and discussed. P. aeruginosa was found the best strain to be employed in the process of Bisphenol A removal. The yield in BPA removal of a P. aeruginosa biofilm grown on GAC and operating in a fluidized bed reactor has been evaluated. The results confirm the usefulness in using biological activated carbon (BAC process) to remove phenol compounds from aqueous systems.

  20. Oxygen Carrier Aided Combustion (OCAC of Wood Chips in a Semi-Commercial Circulating Fluidized Bed Boiler Using Manganese Ore as Bed Material

    Directory of Open Access Journals (Sweden)

    Magnus Rydén

    2016-11-01

    Full Text Available Oxygen Carrier Aided Combustion (OCAC is realized by using an active oxygen-carrying bed material in fluidized bed boilers. The active material is reduced in fuel rich parts of the boiler and oxidized in air rich parts. Advantages could be achieved such as new mechanisms for oxygen transport in space and time. Here calcined manganese ore has been used as active bed material in a 12 MWth circulating fluidized bed boiler. The fuel was wood chips and the campaign lasted more than two weeks. From an operational point of view, manganese ore worked excellently. From the temperature profile of the boiler it can be concluded that fuel conversion was facilitated, especially in the dense bottom bed. The effect did not always translate to reduced emissions, which suggests that final combustion in the cyclone outlet was also influenced. Substituting 10% of the sand bed with manganese ore made it possible to reduce the air to fuel ratio without generating large amounts of CO. The use of 100% manganese ore resulted in higher emissions of CO than the sand reference, but, when combined sulphur feeding, dramatic reductions in CO emissions, up to 90% compared to sand reference, was achieved.

  1. Demonstration of the Anaerobic Fluidized Bed Reactor for Pinkwater Treatment at McAlester Army Ammunition Plant

    National Research Council Canada - National Science Library

    Maloney, Stephen W; Heine, Robert L

    2005-01-01

    .... The bacteria are cultivated on granules of activated carbon contained in a fluidized bed. The demonstration equipment controlled the conditions to maintain favorable conditions for anaerobic bacteria through control of temperature, pH, and nutrients. Fuel grade ethanol was used as the substrate to maintain the bacterial population. The results show that this technique can be successful and less costly than the existing granular activated carbon adsorption process.

  2. A Two‐Fluid model study of hydrogen production via water gas shift in fluidized bed membrane reactors

    OpenAIRE

    J.W. Voncken, Ramon; Roghair, Ivo; Van Sint Annaland, Martin

    2017-01-01

    Fluidized bed membrane reactors have been proposed as a promising reactor concept for the production of ultra-pure hydrogen via Water Gas Shift (WGS). High-flux thin-film dense palladium-based membranes are used to selectively extract hydrogen from the reaction medium, which shifts the thermodynamic equilibrium towards the products’ side, increasing the conversion. A Two-Fluid Model (TFM) has been used to investigate the effect of hydrogen extraction via perm-selective membranes on the WGS re...

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Schrodt, J.T.

    1981-02-01

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

  5. Characterization of a New High-Dose Dry Powder Inhaler (DPI) Based on a Fluidized Bed Design

    Science.gov (United States)

    Farkas, Dale R.; Hindle, Michael; Longest, P. Worth

    2015-01-01

    The objective of this study was to develop a new high-efficiency dry powder inhaler (DPI) that can effectively aerosolize large masses (25–100 mg) of spray dried powder formulations. The DPI was designed to implement a concept similar to a fluidized bed for aerosolization using small mixing balls made of polytetrafluoroethylene (PTFE) along with a larger, hollow dosing sphere filled with the powder. The performance of the fluidized bed DPI was compared, based on emitted dose (ED) and aerosolization efficiency, to other recently developed capsule-based DPIs that were designed to accommodate smaller powder masses (~2–20 mg). The inhalers were tested with spray dried excipient enhanced growth formulations that contained an antibiotic (ciprofloxacin) and hygroscopic excipient (mannitol). The new fluidized bed design produced an ED of 71% along with a mass median aerodynamic diameter (MMAD) of 1.53 µm and fine particle fractions (FPFs) less than 5 µm and 1 µm of 93% and 36%, respectively, when used to deliver a 100 mg loaded mass of EEG powder with the advantage of not requiring multiple capsules. Surprisingly, performance of the device was further improved by removing the mixing balls from the inhaler and only retaining the dose containment sphere. PMID:25986955

  6. Oxidative coupling of methane in a fluidized-bed reactor over a highly active and selective catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Mleczko, L.; Pannek, U. [Ruhr-Universitaet, Bochum (Germany). Lehrstuhl fuer Technische Chemie; Niemi, V.M.; Hiltunen, J. [NESTE OY, Porvoo (Finland). Technology Centre

    1996-01-01

    Oxidative coupling of methane to C{sub 2+} hydrocarbons over a Zr/La/Sr catalyst was investigated in an atmospheric-pressure shallow fluidized-bed reactor (i.d. = 5 cm; H{sub mf} = 1.4--3.2 cm) at temperatures between 800 and 880 C. The catalyst was mechanically and catalytically stable, but its fluidizability was limited; agglomeration and channeling occurred. The highest C{sub 2+} yield amounted to 18.0% (X{sub CH{sub 4}} = 36.5%, S{sub C{sub 2+}} = 49.4%) and 17.2% (X{sub CH{sub 4}} = 36.6%, S{sub C{sub 2+}} = 46.9%) for the diluted and undiluted feed, respectively. These yields are among the highest ones reported in the open literature for oxidative coupling of methane in fluidized beds. In the whole investigated temperature range higher selectivities and yields were obtained upon reducing partial pressures of methane and oxygen but keeping their ratio constant (p{sub CH{sub 4}}/p{sub O{sub 2}} = 2.5). An increased gas velocity or bed height resulted in a drop of C{sub 2+} selectivity.

  7. Characterization of a New High-Dose Dry Powder Inhaler (DPI) Based on a Fluidized Bed Design.

    Science.gov (United States)

    Farkas, Dale R; Hindle, Michael; Longest, P Worth

    2015-11-01

    The objective of this study was to develop a new high-efficiency dry powder inhaler (DPI) that can effectively aerosolize large masses (25-100 mg) of spray dried powder formulations. The DPI was designed to implement a concept similar to a fluidized bed for aerosolization using small mixing balls made of polytetrafluoroethylene along with a larger, hollow dosing sphere filled with the powder. The performance of the fluidized bed DPI was compared, based on emitted dose (ED) and aerosolization efficiency, to other recently developed capsule-based DPIs that were designed to accommodate smaller powder masses (~2-20 mg). The inhalers were tested with spray dried excipient enhanced growth (EEG) formulations that contained an antibiotic (ciprofloxacin) and hygroscopic excipient (mannitol). The new fluidized bed design produced an ED of 71% along with a mass median aerodynamic diameter of 1.53 μm and fine particle fractions powder with the advantage of not requiring multiple capsules. Surprisingly, performance of the device was further improved by removing the mixing balls from the inhaler and only retaining the dose containment sphere.

  8. KAJIAN TEKNIS-EKONOMIS ALAT PENGERING PATI SAGU MODEL CROSS FLOW VIBRO FLUIDIZED BED (Study on Technical-Economic of Sago Starch Dryer Model of Cross Flow Vibro Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Abadi Jading

    2015-02-01

    Full Text Available The purpose of this research was to evaluate performance of vibro cross flow fluidized bed dryer using biomass fuel for drying sago starch. The phase of research were evaluation of dryer heated by a biomass stove using coconut shell as a fuel and observation of the drying temperature, moisture content, drying time, energy analysis, and drying effiviency, as well as calculation of its economic analysis. The dryer has dimension of 200x50x1500 cm for length, width, hight, respectively, and working capacity of 35kg/process. The results showed that biomass fuel consumption for drying sago starch for 7 hours was 12740,00 MJ (70 kg/process and electricity consumption for blower and vibrator was 37,80 MJ. Furthermore, the dryer reduced moisture content of sago starch from 42% (wb to 12% (wb with temperature in the vibrator chamber of 40-60 oC and relative humidity of 50%, as well as ambient temperature of 30 3C and drying efficiency of 46,02%. Economic analysis showed that the dryer had NPV of Rp. 16.002.858, BCR of 1,53, IRR of 35%, and PBP of 3,51 years. Keywords: Cross flow, vibro fluidized bed dryer, biomass stoves, sago starch, financial analysis   ABSTRAK Tujuan penelitian ini adalah melakukan pengujian terhadap alat pengering pati berbasis sagu model cross flow vibrofluidized bed bertenaga biomassa. Tahapan penelitian meliputi pengujian alat pengering menggunakan tungku biomassa berbahan bakar tempurung kelapa dengan melakukan pengamatan suhu selama pengeringan, penurunan kadar air, waktu pengeringan, kebutuhan energi, efisiensi pengering, dan analisis finansial. Konstruksi alat pengering pati sagu model vibro fluidized bed bertenaga biomassa berukuran panjang, lebar dan tinggi masing-masing (200x50x1500 cm, serta memiliki daya tampung atau kapasitas maksimum pati sagu basah 35 kg/proses. Hasil pengujian menunjukkan bahwa alat pengering ini mampu mengeringkan pati sagu selama 7 jam, dengan konsumsi bahan bakar tempurung kelapa sebanyak 70 kg

  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. Low energy single-staged anaerobic fluidized bed ceramic membrane bioreactor (AFCMBR) for wastewater treatment.

    Science.gov (United States)

    Aslam, Muhammad; McCarty, Perry L; Shin, Chungheon; Bae, Jaeho; Kim, Jeonghwan

    2017-09-01

    An aluminum dioxide (Al2O3) ceramic membrane was used in a single-stage anaerobic fluidized bed ceramic membrane bioreactor (AFCMBR) for low-strength wastewater treatment. The AFCMBR was operated continuously for 395days at 25°C using a synthetic wastewater having a chemical oxygen demand (COD) averaging 260mg/L. A membrane net flux as high as 14.5-17L/m(2)h was achieved with only periodic maintenance cleaning, obtained by adding 25mg/L of sodium hypochlorite solution. No adverse effect of the maintenance cleaning on organic removal was observed. An average SCOD in the membrane permeate of 23mg/L was achieved with a 1h hydraulic retention time (HRT). Biosolids production averaged 0.014±0.007gVSS/gCOD removed. The estimated electrical energy required to operate the AFCMBR system was 0.039kWh/m(3), which is only about 17% of the electrical energy that could be generated with the methane produced. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Al2O3 Coatings on Magnesium Alloy Deposited by the Fluidized Bed (FB Technique

    Directory of Open Access Journals (Sweden)

    Gabriele Baiocco

    2018-01-01

    Full Text Available Magnesium alloys are widely employed in several industrial domains for their outstanding properties. They have a high strength-weight ratio, with a density that is lower than aluminum (33% less, and feature good thermal properties, dimensional stability, and damping characteristics. However, they are vulnerable to oxidation and erosion-corrosion phenomena when applied in harsh service conditions. To avoid the degradation of magnesium, several coating methods have been presented in the literature; however, all of them deal with drawbacks that limit their application in an industrial environment, such as environmental pollution, toxicity of the coating materials, and high cost of the necessary machinery. In this work, a plating of Al2O3 film on a magnesium alloy realized by the fluidized bed (FB technique and using alumina powder is proposed. The film growth obtained through this cold deposition process is analyzed, investigating the morphology as well as tribological and mechanical features and corrosion behavior of the plated samples. The resulting Al2O3 coatings show consistent improvement of the tribological and anti-corrosive performance of the magnesium alloy.

  12. Effects of fluidized bed drying on the quality of soybean kernels

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    Hosain Darvishi

    2015-06-01

    Full Text Available The effects of air temperature and velocity on the drying qualities (cracking, bulk density, shrinkage and rehydration of soybean kernels in fluidized bed dryer were investigated. Drying was carried out at 80, 100, 120 and 140 °C and air velocity of 1.8, 3.1 and 4.5 m/s. Soybean kernels were dehydrated from the initial moisture content of 25% (w.b to a final moisture content of 10%. The drying evaluation showed that high drying temperature and air velocity resulted in high cracking and low rehydration ratios (P < 0.05. However, air velocity had no significant effect on bulk density and shrinkage of soybeans. By increasing the temperature and air velocity over their full ranges, drying time decreased from 380 to 50 min. Cracking, bulk density, degree of shrinkage and rehydration ratio varied from 31.80% to 58.22%, 1101.31 to 1186.39 kg/m3, 0.730 to 0.787, and 0.583 to 0.873, respectively. Regression equations were established which can be used for the estimation of the quality parameters as a function of the drying variables.

  13. Numerical Simulation of Fluidized Bed Gasifier for Integrated Gasification Combined Cycle

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    CHEN Ju-hui

    2017-06-01

    Full Text Available The overall thermal efficiency of the integrated gasification combined cycle ( IGCC has not been sufficiently improved. In order to achieve higher power generation efficiency,the advanced technology of IGCC has been developed which is on the basis of the concept of exergy recovery. IGCC systems and devices from the overall structure of opinion,this technology will generate electricity for the integration of advanced technology together,the current utilization of power generation technology and by endothermic reaction of steam in the gasifier,a gas turbine exhaust heat recovery or the solid oxide fuel cell. It is estimated that such the use of exergy recycling has the advantage of being easy to use,separating,collecting fixed CO2,making it very attractive,and can increase the overall efficiency by 10% or more. The characteristics of fluidized bed gasifier,one of the core equipment of the IGCC system,and its effect on the whole system were studied.

  14. Effect of Operating Conditions on Catalytic Gasification of Bamboo in a Fluidized Bed

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    Thanasit Wongsiriamnuay

    2013-01-01

    Full Text Available Catalytic gasification of bamboo in a laboratory-scale, fluidized bed reactor was investigated. Experiments were performed to determine the effects of reactor temperature (400, 500, and 600°C, gasifying medium (air and air/steam, and catalyst to biomass ratio (0 : 1, 1 : 1, and 1.5 : 1 on product gas composition, H2/CO ratio, carbon conversion efficiency, heating value, and tar conversion. From the results obtained, it was shown that at 400°C with air/steam gasification, maximum hydrogen content of 16.5% v/v, carbon conversion efficiency of 98.5%, and tar conversion of 80% were obtained. The presence of catalyst was found to promote the tar reforming reaction and resulted in improvement of heating value, carbon conversion efficiency, and gas yield due to increases in H2, CO, and CH4. The presence of steam and dolomite had an effect on the increasing of tar conversion.

  15. Efficient removal of antibiotics in a fluidized bed reactor by facile fabricated magnetic powdered activated carbon.

    Science.gov (United States)

    Ma, Jianqing; Yang, Qunfeng; Xu, Dongmei; Zeng, Xiaomei; Wen, Yuezhong; Liu, Weiping

    2017-02-01

    Powdered activated carbons (PACs) with micrometer size are showing great potential for enabling and improving technologies in water treatment. The critical problem in achieving practical application of PAC involves simple, effective fabrication of magnetic PAC and the design of a feasible reactor that can remove pollutants and recover the adsorbent efficiently. Herein, we show that such materials can be fabricated by the combination of PAC and magnetic Fe3O4 with chitosan-Fe hydrogel through a simple co-precipitation method. According to the characterization results, CS-Fe/Fe3O4/PAC with different micrometers in size exhibited excellent magnetic properties. The adsorption of tetracycline was fast and efficient, and 99.9% removal was achieved in 30 min. It also possesses good usability and stability to co-existing ions, organics, and different pH values due to its dispersive interaction nature. Finally, the prepared CS-Fe/Fe3O4/PAC also performed well in the fluidized bed reactor with electromagnetic separation function. It could be easily separated by applying a magnetic field and was effectively in situ regenerated, indicating a potential of practical application for the removal of pollutants from water.

  16. Pressurized Fluidized-Bed Hydroretorting of Eastern Oil Shales. Progress report, July--September 1989

    Energy Technology Data Exchange (ETDEWEB)

    Punwani, D.V.; Lau, F.S.; Knowlton, T.M. [and others

    1989-12-01

    The Devonian oil shales of the Eastern United States are a significant domestic energy resource. The overall objective of the 3-year program, initiated in October 1987 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 program is divided into the following eight tasks: Task 1, PFH Scoping Studies; Task 2, PFH Optimization Tests; 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; Task 8, Project Management and Reporting. In order to accomplish all the program objectives, the Institute of Gas Technology, the prime contractor, is working with seven other institutions; the University of Alabama/Mineral Resources Institute, Illinois Institute of Technology, the University of Michigan, the University of Nevada, Ohio State University, Tennessee Technological University and the University of Pittsburgh. This report presents the work performed during the eighth program quarter from July 1 through September 30, 1989.

  17. Statistics of velocity fluctuations of Geldart A particles in a circulating fluidized bed riser

    Science.gov (United States)

    Vaidheeswaran, Avinash; Shaffer, Franklin; Gopalan, Balaji

    2017-11-01

    The statistics of fluctuating velocity components are studied in the riser of a closed-loop circulating fluidized bed with fluid catalytic cracking catalyst particles. Our analysis shows distinct similarities as well as deviations compared to existing theories and bench-scale experiments. The study confirms anisotropic and non-Maxwellian distribution of fluctuating velocity components. The velocity distribution functions (VDFs) corresponding to transverse fluctuations exhibit symmetry, and follow a stretched-exponential behavior up to three standard deviations. The form of the transverse VDF is largely determined by interparticle interactions. The tails become more overpopulated with an increase in particle loading. The observed deviations from the Gaussian distribution are represented using the leading order term in the Sonine expansion, which is commonly used to approximate the VDFs in kinetic theory for granular flows. The vertical fluctuating VDFs are asymmetric and the skewness shifts as the wall is approached. In comparison to transverse fluctuations, the vertical VDF is determined by the local hydrodynamics. This is an observation of particle velocity fluctuations in a large-scale system and their quantitative comparison with the Maxwell-Boltzmann statistics.

  18. Gasification of biochar from empty fruit bunch in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Salleh, M. A.; Hussein Kisiki, N.; Yusuf, H. M.; Ghani, W. A. K. [Department of Chemical and Enviromental Engineering University Putra Malaysia, 43400, Serdang (Malaysia)

    2010-07-15

    A biochar produced from empty fruit bunches (EFB) was gasified in a fluidized bed using air to determine gas yield, overall carbon conversion, gas quality, and composition as a function of temperature. The experiment was conducted in the temperature range of 500-850 {sup o}C. It was observed that biochar has the potential to replace coal as a gasification agent in power plants. Hydrogen gas from biochar was also optimized during the experiment. High temperatures favor H{sub 2} and CO formation. There was an increase of H{sub 2} over the temperature range from 500-850 {sup o}C from 5.53% to 27.97% (v/v), with a heating value of 30 kJ/g. The C conversion in the same temperature range increased from 76% to 84%. Therefore, there are great prospects for the use of biochar from EFB as an alternative fuel in power plants, as a renewable energy providing an alternative path to biofuels. Results from this work enable us to better understand syn gas production under high treatment temperatures. (authors)

  19. Improved Performances of a Fluidized Bed Photoreactor by a Microscale Illumination System

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    Paolo Ciambelli

    2009-01-01

    Full Text Available The performances of a gas-solid two-dimensional fluidized bed reactor in photocatalytic selective oxidation reactions, irradiated with traditional UV lamps or with a microscale illumination system based on UV emitting diodes (UVA-LEDs, have been compared. In the photocatalytic oxidative dehydrogenation of cyclohexane to benzene on MoOx/TiO2-A12O3 catalyst the use of UVA-LEDs modules allowed to achieve a cyclohexane conversion and benzene yield higher than those obtained with traditional UV lamps. The better performances with UVA-LEDs are due to the UVA-LEDs small dimensions and small-angle emittance, which allow photons beam be directed towards the photoreactor windows, reducing the dispersion outside of photoreactor or the optical path length. As a consequence, the effectively illuminated mass of catalyst is greater. We have found that this illumination system is efficient for photo-oxidative dehydrogenation of cyclohexane to cyclohexene on sulphated MoOx/-A12O3 and ethanol to acetaldehyde on VOx/TiO2.

  20. Efficiency Evaluation of Filtration with Fluidized Bed for Treatment of Secondary Effluents for Reuse

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    Mohammad Hosaini

    2013-12-01

    Full Text Available Background & Objectives: Recently, deficient in atmospheric drop and discharges of wastewater effluents leads to serious threat for water resource. For that reason, for prevention of water source pollution and also reuse of wastewater effluents, treatment of such effluents seems to be necessary. Methods: In this work, fluidized bed reactor with a filter was used for treatment of effluents from Shahrak Gharb wastewater treatment plant. Various parameters such as BOD5, COD, TS, TP, TN and turbidity were analyzed. The aluminum sulfate was used as coagulant for enhance removal efficiency. Results: The results of present work demonstrate that present system had higher treatment potential for secondary effluents. The amount of BOD5, COD and TP in system effluents was reached to below 1.75, 3.23, 0.5 mg/L, respectively. No removal efficiency was observed for TN. In addition, the amount of turbidity in system effluent was reached to below 1.04 NTU. The system represents lower removal efficiency for TS. In addition, higher removal efficiency is in the range of 5 to 7.5 m/h and increasing of surface loading upon to 10 m/h will decreases the removal efficiency. Conclusion: On general, the system represents higher removal potential for treatment of secondary effluent for reuse application.