WorldWideScience

Sample records for circulating fluidised bed

  1. Bed-To-Wall Heat Transfer in a Supercritical Circulating Fluidised Bed Boiler

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2014-06-01

    Full Text Available The purpose of this work is to find a correlation for heat transfer to walls in a 1296 t/h supercritical circulating fluidised bed (CFB boiler. The effect of bed-to-wall heat transfer coefficient in a long active heat transfer surface was discussed, excluding the radiation component. Experiments for four different unit loads (i.e. 100% MCR, 80% MCR, 60% MCR and 40% MCR were conducted at a constant excess air ratio and high level of bed pressure (ca. 6 kPa in each test run. The empirical correlation of the heat transfer coefficient in a large-scale CFB boiler was mainly determined by two key operating parameters, suspension density and bed temperature. Furthermore, data processing was used in order to develop empirical correlation ranges between 3.05 to 5.35 m·s-1 for gas superficial velocity, 0.25 to 0.51 for the ratio of the secondary to the primary air, 1028 to 1137K for bed temperature inside the furnace chamber of a commercial CFB boiler, and 1.20 to 553 kg·m-3 for suspension density. The suspension density was specified on the base of pressure measurements inside the boiler’s combustion chamber using pressure sensors. Pressure measurements were collected at the measuring ports situated on the front wall of the combustion chamber. The obtained correlation of the heat transfer coefficient is in agreement with the data obtained from typical industrial CFB boilers.

  2. Particle motion in fluidised beds

    International Nuclear Information System (INIS)

    Gas fluidised beds are important components in many process industries, e.g. coal combustors and granulators, but not much is known about the movement of the solids. Positron Emission Particle Tracking (PEPT) enables the movement of a single, radioactive tracer particle to be followed rapidly and faithfully. Experiments were carried out in columns sized between 70 and 240mm. diameter, operating in the bubbling regime at ambient process conditions using particles of group B and D (Geldart Classification). Particle motion was tracked and the data applied to models for particle movement at the gas distributor as well as close to other surfaces and to models for particle circulation in beds of cohesive particles. In the light of these data, models for particle and bubble interaction, particle circulation, segregation, attrition, erosion, heat transfer and fluidised bed scale-up rules were reassessed. Particle motion is directly caused by bubble motion, and their velocities were found to be equal for particles travelling in a bubble. PEPT enables particle circulation to be measured, giving a more accurate correlation for future predictions. Particle motion follows the scale-up rules based on similarities of the bubble motion in the bed. A new group of parameters was identified controlling the amount of attrition in fluidised beds and a new model to predict attrition is proposed. (author)

  3. Sulphation of calcium-based sorbents in circulating fluidised beds under oxy-fuel combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Francisco Garcia-Labiano; Luis F. de Diego; Alberto Abad; Pilar Gayan; Margarita de las Obras-Loscertales; Aranzazu Rufas; Juan Adanez [Instituto de Carboquimica (CSIC), Zaragoza (Spain). Dept. Energy and Environment

    2009-07-01

    Sulphur Retention (SR) by calcium-based sorbents is a process highly dependent on the temperature and CO{sub 2} concentration. In circulating fluidised beds combustors (CFBC's) operating under oxy-fuel conditions, the sulphation process takes place in atmospheres enriched in CO{sub 2} with bed concentrations that can vary from 40 to 95%. Under so high CO{sub 2} concentrations, very different from that in conventional coal combustion atmosphere with air, the calcination and sulphation behaviour of the sorbent must be defined to optimise the SR process in the combustor. The objective of this work was to determine the SO{sub 2} retention capacity of a Spanish limestone at typical oxy-fuel conditions in CFBC's. Long term duration tests of sulphation (up to 24 h), to simulate the residence time of sorbents in CFBC's, were carried out by thermogravimetric analysis (TGA). Clear behaviour differences were found under calcining and non-calcining conditions. Especially relevant was the result obtained at calcining conditions but close to the thermodynamic temperature given for sorbent calcination. This situation must be avoided in CFBC's because the CO{sub 2} produced inside the particle during calcination can destroy the particles if a non-porous sulphate product layer has been formed around the particle. The effect of the main variables on the sorbent sulphation such as SO{sub 2} concentration, temperature, and particle size were analysed in the long term TGA tests. These data were also used to determine the kinetic parameters for the sulphation under oxy-fuel combustion conditions, which were able to adequately predict the sulphation conversion values in a wide range of operating conditions. 20 refs., 5 figs., 2 tabs.

  4. Gas mixing in a pilot scale (500 KW{sub th}) air blown circulating fluidised bed biomass gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Kersten, S.R.A.; Moonen, R.H.W.; Oosting, T.P. [ECN Biomass, Petten (Netherlands); Prins, W.; Van Swaaij, W.P.M. [Faculty of Chemical Engineering, University of Twente, Enschede (Netherlands)

    2000-07-01

    To study the gas mixing capacity of circulating fluidised bed (CFB) biomass gasifiers, radial and axial gas concentration profiles have been measured and interpreted in both a hot pilot scale biomass gasifier (100 kg/hr fuel) and a cold-flow set-up. The presented data of the pilot scale gasifier are unique and provide new insight in the radial gas mixing capacity of circulating fluidised bed gasifiers. Gas mixing is an important process because the effectiveness of a CFB biomass gasifier, regarding conversion of carbon and tars in the product gas, depends among other things on the degree of reactant mixing. At five different axial positions, in the pilot plant, especially developed probes are installed to withdraw gases from the interior of the reactor. They can be moved freely over the reactor diameter, so full radial profiles can be obtained at each axial position. In the cold-flow set-up similar probes are used to determine radial dispersion coefficients as a function of process variables such as solids flux, gas velocity and additional internals. Considerable radial gas phase concentration gradients have been observed in the pilot plant gasifier, with a difference between wall and centre concentrations up to a factor 3. It must be concluded that the radial gas mixing is far from ideal. On basis of these pilot plant data and a suitable reactor model it can be concluded that the radial Peclet number of the dilute region is in the order of 1000. Such a value excludes the radial mixing of gases almost entirely. Simulations indicate that the occurrence of a parabolic gas velocity profile (also observed in earlier hydrodynamic studies) and a possibly non-uniform biomass distribution, are major causes for steep gradients in the radial gas concentration profiles. From the experiments in the cold-flow set-up it can be concluded that in the dilute region of the riser the radial mixing intensity decreases due to presence of solids. This can be ascribed to a reducing

  5. A comparison of circulating fluidised bed combustion and gasification power plant technologies for processing mixtures of coal, biomass and plastic waste

    Energy Technology Data Exchange (ETDEWEB)

    McIlveen-Wright, D.R.; Huang, Y.; McMullan, J.T. [NICERT, University of Ulster at Jordanstown, Newtownabbey BT37 0QB, Northern Ireland (United Kingdom); Pinto, F.; Franco, C.; Gulyurtlu, I. [INETI-DEECA, Estrada do Paco do Lumiar, 22, 1649-038 Lisboa (Portugal); Armesto, L.; Cabanillas, A. [CIEMAT, Avda Complutense, 22, 28040 Madrid (Spain); Caballero, M.A.; Aznar, M.P. [Chemical and Environmental Engineering Department, Centro Politecnico Superior, Maria de Luna, University of Saragossa, 50018 Saragossa (Spain)

    2006-09-15

    Environmental regulations concerning emission limitations from the use of fossil fuels in large combustion plants have stimulated interest in biomass for electricity generation. The main objective of the present study was to examine the technical and economic viability of using combustion and gasification of coal mixed with biomass and plastic wastes, with the aim of developing an environmentally acceptable process to decrease their amounts in the waste stream through energy recovery. Mixtures of a high ash coal with biomass and/or plastic using fluidised bed technologies (combustion and gasification) were considered. Experiments were carried out in laboratory and pilot plant fluidised bed systems on the combustion and air/catalyst and air/steam gasification of these feedstocks and the data obtained were used in the techno-economic analyses. The experimental results were used in simulations of medium to large-scale circulating fluidised bed (CFB) power generation plants. Techno-economic analysis of the modelled CFB combustion systems showed efficiencies of around 40.5% (and around 46.5% for the modelled CFB gasification systems) when fuelled solely by coal, which were only minimally affected by co-firing with up to 20% biomass and/or wastes. Specific investments were found to be around $2150/kWe to $2400/kWe ($1350/kWe to $1450/kWe) and break-even electricity selling prices to be around $68/MWh to $78/MWh ($49/MWh to $54/MWh). Their emissions were found to be within the emission limit values of the large combustion plant directive. Fluidised bed technologies were found to be very suitable for co-firing coal and biomass and/or plastic waste and to offer good options for the replacement of obsolete or polluting power plants. (author)

  6. A comparison of circulating fluidised bed combustion and gasification power plant technologies for processing mixtures of coal, biomass and plastic waste

    International Nuclear Information System (INIS)

    Environmental regulations concerning emission limitations from the use of fossil fuels in large combustion plants have stimulated interest in biomass for electricity generation. The main objective of the present study was to examine the technical and economic viability of using combustion and gasification of coal mixed with biomass and plastic wastes, with the aim of developing an environmentally acceptable process to decrease their amounts in the waste stream through energy recovery. Mixtures of a high ash coal with biomass and/or plastic using fluidised bed technologies (combustion and gasification) were considered. Experiments were carried out in laboratory and pilot plant fluidised bed systems on the combustion and air/catalyst and air/steam gasification of these feedstocks and the data obtained were used in the techno-economic analyses. The experimental results were used in simulations of medium to large-scale circulating fluidised bed (CFB) power generation plants. Techno-economic analysis of the modelled CFB combustion systems showed efficiencies of around 40.5% (and around 46.5% for the modelled CFB gasification systems) when fuelled solely by coal, which were only minimally affected by co-firing with up to 20% biomass and/or wastes. Specific investments were found to be around $2150/kWe to $2400/kWe ($1350/kWe to $1450/kWe) and break-even electricity selling prices to be around $68/MWh to $78/MWh ($49/MWh to $54/MWh). Their emissions were found to be within the emission limit values of the large combustion plant directive. Fluidised bed technologies were found to be very suitable for co-firing coal and biomass and/or plastic waste and to offer good options for the replacement of obsolete or polluting power plants. (author)

  7. Leaching Behavior of Circulating Fluidised Bed MSWI Air Pollution Control Residue in Washing Process

    Directory of Open Access Journals (Sweden)

    Zhiliang Chen

    2016-09-01

    Full Text Available In this study, air pollution control (APC residue is conducted with water washing process to reduce its chloride content. A novel electrical conductivily (EC measurement method is proposed to monitor the dynamic change of chloride concentrations in leachate as well as the chloride content of the residue. The method equally applies to various washing processes with different washing time, liquid/solid ratio and washing frequency. The results show that washing effectively extracts chloride salts from APC residues, including those from circulating fluidized bed (CFB municipal solid waste incineration (MSWI. The most appropriate liquid/solid ratio and washing time in the first washing are found to be around 4 L water per kg of APC residue and 30 min, respectively, and washing twice is required to obtain maximum dissolution. The pH value is the major controlling factor of the heavy metals speciation in leachate, while chloride concentration also affects the speciation of Cd. Water washing causes no perceptible transfer of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs from the APC residue to leachate. The chloride concentration is strongly related with electrical conductivity (EC, as well as with the concentrations of calcium, sodium and potassium of washing water. Their regression analyses specify that soluble chloride salts and EC could act as an indirect indicator to monitor the change of chloride concentration and remaining chloride content, thus, contributing to the selection of the optimal washing conditions.

  8. Flow structure formation and evolution in circulating gas-fluidised beds

    NARCIS (Netherlands)

    Li, Jie; Kuipers, J.A.M.

    2004-01-01

    The occurrence of heterogeneous flow structures in gas-particle flows seriously affects the gas-solid contacting and transport processes in high-velocity gas-fluidized beds. Particles do not disperse uniformly in the flow but pass through the bed in a swarm of clusters. The so-called "core-annulus"

  9. Flow structure formation and evolution in circulating gas-fluidised beds

    OpenAIRE

    Li, Jie; Kuipers, J.A.M.

    2004-01-01

    The occurrence of heterogeneous flow structures in gas-particle flows seriously affects the gas-solid contacting and transport processes in high-velocity gas-fluidized beds. Particles do not disperse uniformly in the flow but pass through the bed in a swarm of clusters. The so-called "core-annulus" structure in the radial direction and "S" shaped axial distribution of solids concentration characterize the typical flow structure in the system. A computational study, using the discrete particle...

  10. Fluidised-bed combustion of gasification residue

    Energy Technology Data Exchange (ETDEWEB)

    Korpela, T.; Kudjoi, A.; Hippinen, I.; Heinolainen, A.; Suominen, M.; Lu Yong [Helsinki Univ. of Technology (Finland). Lab of Energy Economics and Power Plant Engineering

    1996-12-01

    Partial gasification processes have been presented as possibilities for future power production. In the processes, the solid materials removed from a gasifier (i.e. fly ash and bed material) contain unburnt fuel and the fuel conversion is increased by burning this gasification residue either in an atmospheric or a pressurised fluidised-bed. In this project, which is a part of European JOULE 2 EXTENSION research programme, the main research objectives are the behaviour of calcium and sulphur compounds in solids and the emissions of sulphur dioxide and nitrogen oxides (NO{sub x} and N{sub 2}O) in pressurised fluidised-bed combustion of gasification residues. (author)

  11. Ruedersdorf cement works substitutes raw material and fuel by means of a circulating fluidised bed; Roh- und Brennstoffsubstitution mit einer Zirkulierenden Wirbelschicht im Zementwerk Ruedersdorf

    Energy Technology Data Exchange (ETDEWEB)

    Scur, P. [Ruedersdorfer Zement GmbH, Ruedersdorf (Germany)

    1998-09-01

    The purpose of the present paper is to point out the great potential the cement industry holds for the utilisation of waste materials. There are meanwhile sufficient studies and measuring results to demonstrate the environmental acceptability of the processes and products involved. The solution found for Ruedersdorf cement kiln of using a circulating a fluidised bed for waste utilisation is a good example of the potential still available for conserving natural resources and landfill area. Efficient industrial applications of this kind should become a future mainstay of the waste industry. [Deutsch] In dem vorliegenden Beitrag sollte gezeigt werden, dass die Zementindustrie ueber ein hohes Potential zur thermischen und stofflichen Verwertung von Abfallstoffen verfuegt. Es liegen ausreichende Untersuchungen und konkrete Messergebnisse vor, mit denen die Umweltvertraeglichkeit von Prozess und Produkt nachgewiesen werden kann. Die Loesung zur Abfallverwertung an der Ruedersdorfer Zementofenanlage mit Hilfe einer Zirkulierenden Wirbelschicht ist ein Beispiel fuer die Reserven zur Schonung natuerlicher Ressourcen und zur Einsparung von Deponieraeumen. Derartige sinnvolle industrielle Einsatzmoeglichkeiten sollten ein wichtiges Standbein fuer die zukuenftige Abfallwirtschaft sein. (orig.)

  12. New Developments in Spinning Fluidised Bed Incineration Technology

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    At the present time, the sewage treatment plants in the UK produce about 25 million tons of sewage sludge each year at a concentration of 4% solids. New regulations forbid sea dumping and in the near future new incinerators will be required to dispose of about 5 million tons per year. Bubbling fluidised bed incinerators are widely used to burn sewage sludge at a typical consumption rate of about 0.02kg(dry)·s-1·m2, and it follows that over 300 conventional fluidised bed incinerators of 3m diameter could be required to cope with the increased demand.At Sheffield University Waste Incineration Centre (SUWIC) research work is being carried out to develop a novel spinning fluidised bed incinerator. The key factor to note is that when air flows up through a bed of near mono-sized particles, it fluidises when the pressure drop across the bed is equal to the weight of the bed. Normally, the weight of the bed is determined by gravity. However, if the bed is contained by a cylindrical air distributor 'plate' that is rotating rapidly about its axis, then the effective weight of the bed can be increased dramatically. The airflow passing through the bed can be increased proportionally to the "g" level produced by the rotation and it follows that the process has been intensified. In exploratory tests with a spinning fluidised bed we have achieved combustion intensities with coal combustion as high as 100MW/m3. A problem with burning coal is that it was difficult to remove the heat and rotating water seals had to be used to transfer cooling water into the bed. In the case of sewage and other sludges, this problem does not exist since the flue gases can remove the small amount of heat released. The rotating fluidised bed sludge incinerator is a novel device, which is very compact. It is able to solve the turndown problem encountered with conventional fluidised beds by simply changing the rotation speed. Bearing in mind that a centrifugal sludge de-watering unit is already used

  13. VOC emission control by circulating fluidized bed adsorption; Controle de l'emission de composes organiques volatils par adsorption en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Song, W.

    2003-12-15

    This work deals with the circulating fluidized bed technology, applied to the elimination by adsorption of volatile organic compounds (VOCs), like toluene, in a gas flow. In the process, the adsorbent (millimetric spherical grains of micro-porous carbon) is moved by a strong flow rate of gas inside a vertical tube without lining. Mass and heat transfers are very important and important volumes of compounds can be processed. This work presents the determination of the adsorption equilibrium, the description of the experimental facility and of the results of experiments, the development of an original model of the process which combines a flow model and a mass transfer model, a parametric study of this model, and finally, some extensions of the process principle to staged operations with pressure variation or temperature variation cycles. (J.S.)

  14. Biofluid process: fluidised-bed gasification of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Dittrich, A. [ATEKO a.s., Hradec Kralove (Czech Republic)

    1996-12-31

    Fluidised-bed gasification of biomass was developed by ATEKO by using long-term experience from coal gasification. An experimental unit was built and a number of tests, first with sawdust gasification, were carried out. A gas combustion engine combined with a power generator was installed and operated in power production. (orig.)

  15. Discrete element modelling of fluidised bed spray granulation

    NARCIS (Netherlands)

    Goldschmidt, M.J.V.; Weijers, G.G.C.; Boerefijn, R.; Kuipers, J.A.M.

    2002-01-01

    A novel discrete element spray granulation model capturing the key features of fluidised bed hydrodynamics, liquid-solid contacting and agglomeration is presented. The model computes the motion of every individual particle and droplet in the system, considering the gas phase as a continuum. Micro sc

  16. Discrete element modelling of fluidised bed spray granulation

    NARCIS (Netherlands)

    Goldschmidt, M.J.V.; Weijers, G.G.C.; Boerefijn, R.; Kuipers, J.A.M.

    2003-01-01

    A novel discrete element spray granulation model capturing the key features of fluidised bed hydrodynamics, liquid¿solid contacting and agglomeration is presented. The model computes the motion of every individual particle and droplet in the system, considering the gas phase as a continuum. Microsca

  17. 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

  18. Modelling the bed characteristics in fluidised-beds for top-spray coating processes

    Institute of Scientific and Technical Information of China (English)

    Mike Vanderroost; Frederik Ronsse; Koen Dewettinck; Jan G.Pieters

    2012-01-01

    A particle sub-model describing the bed characteristics of a bubbling fluidised bed is presented.Atomisation air,applied at high pressures via a nozzle positioned above the bed for s pray formation,is incorporated in the model since its presence has a profound influence on the bed characteristics,though the spray itself is not yet considered.A particle sub-model is developed using well-known empirical relations for particle drag force,bubble growth and velocity and particle distribution above the fluidised-bed surface.Simple but effective assumptions and abstractions were made concerning bubble distribution,particle ejection at the bed surface and the behaviour of atomisation air flow upon impacting the surface of a bubbling fluidised bed.The model was shown to be capable of predicting the fluidised bed characteristics in terms of bed heights,voidage distributions and solids volume fractions with good accuracy in less than 5 min of calculation time on a regular desktop PC.It is therefore suitable for incorporation into general process control models aimed at dynamic control for process efficiency and product quality in top-spray fluidised bed coating processes.

  19. Formation of abrasive hollow particles in lignite-fired fluidised bed boilers; Bildung abrasiver Hohlpartikel in braunkohlenbefeuerten Wirbelschichtkessel

    Energy Technology Data Exchange (ETDEWEB)

    Kappler, Uta [RWE Power AG, Koeln (Germany). Forschung und Entwicklung Hauptverwaltung; Roeper, Bernhard [RWE Power AG, Grevenbroich (Germany). Technische Dienste Kraftwerk Frimmersdorf; Voss, Petra [RWE Power AG, Bergheim (Germany). Forschung und Entwicklung Kraftwerk Niederaussem

    2013-04-01

    The formation of voluminous and highly abrasive hollow particles in raw-lignite-fired circulating fluidised-bed (CFB) boilers of RWE Power AG is a well-known phenomenon. Operational measures were taken to avoid particle formation and related damage. By the end of 2011 another boiler damage occurred. Within the scope of root cause analyses the hollow particles were investigated and a model for particle genesis was developed. Based on these results further measures for the avoidance of particle formation were shown. The formation probability of similar hollow particles in biomass-fired fluidised-bed plants was assessed theoretically.

  20. Discrete element modelling of fluidised bed spray granulation

    OpenAIRE

    Goldschmidt, MJV; Weijers, GGC; Boerefijn, R; Kuipers, JAM Hans

    2002-01-01

    A novel discrete element spray granulation model capturing the key features of fluidised bed hydrodynamics, liquid-solid contacting and agglomeration is presented. The model computes the motion of every individual particle and droplet in the system, considering the gas phase as a continuum. Micro scale processes such as particle-particle collisions, droplet-particle coalescence and agglomeration are directly taken into account by simple closure models. Simulations of the hydrodynamic behaviou...

  1. A CFD Model for Fluid Dynamics in a Gas-fluidised Bed

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kai; Stefano Brandani

    2004-01-01

    A modified particle bed model derived from the two-fluid momentum balance equations was employed to predict the gas-fluidised bed behaviour. Additional terms are included in both the fluid and the particle momentum balance equations to take into account the effect of the dispersed solid phase. This model has been extended to two-dimensional formulations and has been implemented in the commercial code CFX 4.3. The model correctly simulates the homogeneous fluidisation of Geldart Group A and the bubbling fluidisation of Geldart Group B in gas-solid fluidised beds.

  2. Modelling of seed drying in fluidised and spouted bed dryers

    OpenAIRE

    Jittanit, W.; Srzednicki, G.; Driscoll, R

    2010-01-01

    Drying experiments were conducted in the fluidised bed dryer (FBD) and spouted bed dryer (SBD) at temperature 40-80°C using maize, rice and wheat seed samples. The experimental data were fitted into four thin-layer drying models by least square method. As a result, Page’s model and two-compartment model were the best-fitted models. Due to the limitation of these models, Page’s model and the twocompartment model were modified by adding the drying temperature term. Subsequently, these models co...

  3. TREATMENT OF POME BY PILOT PLANT ANAEROBIC FLUIDISED BED REACTOR

    OpenAIRE

    Abdullah Al-Mamun; Azni Idris

    2010-01-01

    A pilot scale anaerobic fluidised bed reactor (AnFBR) of 2000 L capacity was studied to determine its performance to treat palm oil mill effluent (POME). The pilot plant was operated at ambient temperature with diluted POME as substrate. It took 17 days for the start-up of the reactor with pre-seeded sand media. The AnFBR was capable to remove a large portion of organics at relatively shorter retention time. Maximum and minimum COD removal efficiency of 85% and 65% were attained at a ...

  4. Fuzzy control structure for an anaerobic fluidised bed

    Science.gov (United States)

    Hernández, Salvador Carlos; Sanchez, Edgar N.; Béteau, Jean-François

    2012-12-01

    This article deals with the design of a fuzzy control strategy for a fluidised bed reactor, which is used for anaerobic wastewater treatment. This strategy is composed of a supervisor system and two PI L/A controllers. In addition, a biomass observer, designed on the basis of the Takagi-Sugeno approach considering a principal component analysis, is used with supervision proposals. The supervisor is also designed following the Takagi-Sugeno methodology; it detects the process state, selects and applies the most adequate control action in order to avoid the washout region. On the other side, two control actions are designed for bicarbonate regulation using the PI/LA technique: adding a base and dilution rate. These control actions, as well as the open loop operation, are selected by the supervisor in order to reject disturbances on the substrate influent allowing at the same time a high methane production. The applicability of the proposed structure in a fluidised bed reactor is illustrated via simulations.

  5. TREATMENT OF POME BY PILOT PLANT ANAEROBIC FLUIDISED BED REACTOR

    Directory of Open Access Journals (Sweden)

    Abdullah Al-Mamun

    2010-09-01

    Full Text Available A pilot scale anaerobic fluidised bed reactor (AnFBR of 2000 L capacity was studied to determine its performance to treat palm oil mill effluent (POME. The pilot plant was operated at ambient temperature with diluted POME as substrate. It took 17 days for the start-up of the reactor with pre-seeded sand media. The AnFBR was capable to remove a large portion of organics at relatively shorter retention time. Maximum and minimum COD removal efficiency of 85% and 65% were attained at a loading rate of 4.0 and 13.8 kgCOD/m3.d. BOD and TSS removal rates varied within the range of 64% - 91% and 68% - 89%, respectively. The AnFBR exhibited low sludge production with lower sludge volume indices (SVI. Maximum and minimum effluent indices for the effluent were 35 mL/g and 11 mL/g, respectively. Low SVI values indicated that, anaerobic fluidised bed reactors generate less sludge with fast settling properties. Promising performance at ambient temperature and for detention time shorter than the present practices supported the possibility of AnFBR to treat POME to meet the new requirement set by the DOE Malaysia.

  6. Remediation of ash problems in fluidised-bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Vuthaluru, H.B.; Zhang, D.K. [Curtin University of Technology, Perth, WA (Australia). School of Chemical Engineering

    2001-03-01

    The paper reports the control methods for mitigating particle agglomeration and bed defluidisation during fluidised-bed combustion of low-rank coals. A laboratory scale spouted-bed combustion system is used to study the effectiveness of several control methods including the use of alternative bed materials, mineral additives, pretreatment of coal and coal blending. Sillimanite, bauxite, calcite and magnesite were used as alternative bed materials whereas mineral additives viz. clay, kaosil and bauxite were injected into the combustion system while burning South Australian low-rank coal at 800{degree}C. Samples of the same coal subjected to water-washing, Al pretreatment and Ca pretreatment are also tested in the spouted-bed combustor. In addition, experiments were conducted with several coal blends prepared at ratios of 50:50 and 90:10 from two lignites and one sub-bituminous coal. Experiments showed that all the control methods are effective to different extends in reducing ash problems and resulted in extended combustion operation. Tests with alternative bed materials and mineral additives showed trouble free-operation for longer periods (7-12 h at 800{degree}C) than with sand runs at the same bed temperature. Wet pretreatment and coal blending were also found to be effective and resulted in extended combustion operation (9-12 h at 800{degree}C). Chemical analyses indicated that formation of low temperature eutectics was suppressed by Al/Ca/Mg-rich phases in ash coating of bed particles. This was identified as the main mechanism for prevention of ash problems observed with the use of alternative bed materials, mineral additives, pretreated coals and coal blends. 23 refs., 9 figs., 7 tabs.

  7. Surface characterisation of carbon fibre recycled using fluidised bed

    Science.gov (United States)

    Jiang, G.; Pickering, S. J.; Walker, G. S.; Wong, K. H.; Rudd, C. D.

    2008-02-01

    X-ray photoelectron spectroscopy (XPS) was used to investigate the surface of carbon fibres recycled using a high-temperature fluidised bed. The interfacial shear strength of the recycled carbon fibres with epoxy resin was examined using a micro-droplet test. The corresponding as received carbon fibres were used as control samples. It was shown that the recycling process converted some of the surface hydroxyl groups into carbonyl and carboxylic groups due to the effect of heat in atmosphere of air. The overall O/C ratio was not changed significantly. The interfacial shear strength with epoxy resin was not affected by the change of surface oxygen composition. It was also shown that surface texture may play a dominant role in interfacial bonding performance.

  8. Pressurised fluidised bed combustion: an alternative for the clean use of coal. La combustion en lecho fluido a presion, una alternativa de uso limpio del carbon en desarrollo

    Energy Technology Data Exchange (ETDEWEB)

    Beucom O Perez-Zamora, V.; Menendez Perez, J.A.E. (ENDESA, Madrid (Spain))

    1988-11-01

    Atmospheric fluidised bed combustion is an alternative worthy of consideration. It is a solution which maintains or even increases output slightly and, in the circulating fluidised bed variety, has the advantage of being able to burn an inconsistent quality of coal with a high sulphur content. The most important question is to what output this method can be developed whilst remaining competitive with other systems. There is a tendency to assume that atmospheric fluidised bed combustors can be developed up to 250 MW and that more powerful installations for electricity generation use systems with a higher output. In any case, this is no more than a general and preliminary observation. Its validity will be proved by the technical and economic results achieved with high output systems and by the availability of coal of the required mix of quality and price. 10 tabs., 10 figs.

  9. Beneficiation of pulverized coal combustion fly ash in fluidised bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Cammarota, A.; Chirone, R.; Solimene, R.; Urciuolo, M. [Istituto di Ricerche sulla Combustione - C.N.R., P.le V. Tecchio 80, 80125 Napoli (Italy)

    2008-07-15

    The paper addresses the thermal treatment of pulverized coal combustion fly ash belonging to the group C of Geldart powder classification in unconventional configurations of fluidised bed reactors. A sound-assisted fluidised bed combustor operated at 850 and 750 C, and a fluidised bed combustor characterized by a conical geometry, operated at 850 C, are the two lab-scale reactors tested. Combustion experiments have been carried out at different air excesses, ranging between 10% and 170%, and in the case of the conical fluidization column with different bed inventory. Both tested configurations have been proved to be efficient to reduce the carbon content initially present in the fly ash of 11%{sub w}, to a very low level, generally smaller than 1%{sub w}. Both the fly ash residence time in the reactor and the air excess strongly influenced the reactor performance. Residence times of 3-4 min and 10-60 min have been estimated for experiments carried out with the sound-assisted fluidised bed combustor and with the conical fluidised bed combustor, respectively. Regarding the possibility of a concurrent reduction of unburned carbon in the ash and of a particle size separation of the beneficiated material, on the basis of the obtained experimental data, the sound-assisted fluidised bed combustor is not able to separate the broad particle size distribution of the fly ash in different outlet solid streams. The use of a conical fluidised bed combustor is promising to realize an efficient separation of the inlet broad particle size distribution of the fly ash fed to the reactor into narrower outlet solid streams extracted from different locations: combustor exit, top and bottom of the bed. In this framework a hydrodynamic characterization of binary mixtures in a conical fluidised bed column carried out at ambient and high temperature (850 C) has demonstrated that the operating conditions of the conical fluidised bed combustor can be chosen on the basis of a compromise

  10. Biomass ash - bed material interactions leading to agglomeration in fluidised bed combustion and gasification

    Energy Technology Data Exchange (ETDEWEB)

    Visser, H.J.M.; Hofmans, H.; Huijnen, R.; Kastelein, R.; Kiel, J.H.A. [ECN Biomass, Petten (Netherlands)

    2000-07-01

    The present study has been aimed at improving the fundamental understanding of mechanisms underlying agglomeration and defluidisation in fluidised bed combustion and gasification of biomass and waste. To this purpose dedicated lab-scale static heating and fluidisation experiments have been conducted with carefully selected and prepared ashes and bed materials, viz. straw ash/sand and willow ash/sand mixtures, mullite subjected to straw gasification and artificially coated mullite. The main conclusion is that ash/bed material interaction processes are very important and often determine the bed agglomeration and defluidisation tendency. In the static heating experiments with both ash/sand mixtures, partial melting-segregation of ash components and dissolution/reaction with the bed material are processes that determine the melt composition. This melt composition and behaviour can deviate considerably form expectations based on ash-only data. Artificially coated bed materials prove to be very useful for systematic studies on the influence of coating composition and thickness on agglomeration tendency. For the coated mullite samples, different stages in the defluidisation process are identified and the influence of coating properties (thickness, composition, morphology) and operating parameters is elucidated. The behaviour of the mullite appears to be dominated by a remnant glass phase. On the one hand, this glass phase accounts for an alkali-getter capability, while on the other hand it is mainly responsible for agglomeration at temperatures {>=} 800C. 3 refs.

  11. Experimental study of the mechanisms of CO{sub 2} capture by calcium cycle under circulating fluidized bed conditions; Etude experimentale des mecanismes de capture du CO{sub 2} par cycle calcium en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Hoteit, A

    2006-06-15

    The work undertaken in this Thesis in partnership with department R and D of ALSTOM Power Boilers, CEMEX and the ADEME, relates to the experimental study of various phenomena associated to CO{sub 2} capture under circulating fluidized bed conditions. The size of particles, temperature and the CO{sub 2} concentration have an influence on the limestone calcination reaction. The reaction of carbonation of lime is not total. During successive cycles of calcination/carbonation, the rate of carbonation obtained with hydrated lime is increasingly higher than that obtained with the lime. Under continuously reducing conditions, the decomposition of sulphates present in the bed ashes is not total. This decomposition is total under reduction/oxidation cycles. A modeling of calcination allowed to determine the intrinsic kinetic constants of calcination and carbonation. (author)

  12. Fluidisation and dispersion behaviour of small high density pellicular expanded bed adsorbents

    DEFF Research Database (Denmark)

    Theodossiou, Irini; Elsner, H.D.; Thomas, Owen R. T.;

    2002-01-01

    The fluidisation and dispersion properties of various agarose-based expanded bed matrices-small high density stainless steel cored prototypes and standard commercial types-were studied in I-cm diameter expanded bed contactors in which fluid entering the column base is locally stirred. In all cases...

  13. Comparison of waste water treatment between completely mixed and fluidised bed reactor; development and structure of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Toman, M.; Mejac, B.

    1988-08-01

    The aerobic biological treatment of waste water from production of semisynthetic antibiotics in a completely mixed reactor and in a fluidised bed reactor was studied. The formation and development of new biomass on the sand of a fluidised bed was observed, so that differences in the structure of organisms of the concomitant biocenosis could be detected. In a fluidised bed reactor the same quality of treatednwater was gained on account of a 4-5 times higher volumetric and hydraulic loading as it was the case with a conventional activated sludge plant. The biocenosis of the fluidised bed was abundant in individua and species. The biofilm of the sand depended on substrate degradation rate as well as on rubbing among the sand particles. An optimal biofilm developed on the sand of a fluidised bed reactor 10 to 15 days after the experiment had began, and that condition remained unchanged as the experiment continued.

  14. Granular dynamics simulation of segregation phenomena in bubbling gas-fluidised beds

    NARCIS (Netherlands)

    Hoomans, B.P.B.; Kuipers, J.A.M.; Swaaij, van W.P.M.

    2000-01-01

    A hard-sphere discrete particle model of a gas-fluidised bed was used in order to simulate segregation phenomena in systems consisting of particles of different sizes. In the model, the gas-phase hydrodynamics is described by the spatially averaged Navier¿Stokes equations for two-phase flow. For eac

  15. Numerical modelling 2 D and 3 D of circulating fluidized bed: application to the realization of regime diagrams; Modelisation numerique 2D et 3D de lit fluidise circulant: application a la realisation du diagramme des regimes

    Energy Technology Data Exchange (ETDEWEB)

    Begis, J.; Balzer, G.

    1997-02-01

    The numerical modelling of internal CFB boilers flows faced with complex phenomenons due to the flows un-stationariness, the heterogeneousness of the particle size distribution, and interactions between the two phases and the walls. Our study consisted in applying numerical models to the experimental configuration of cold circulating fluidized bed studied at the Cerchar. Special attention was given to the analysis of particles - wall interactions models, stemming from Jenkins (1992) and Louge`s (1994) theories, as well as the influence of the particles on fluid turbulence. In order to realize numerical simulations, we have used Eulerian two-phases flow codes developed at NHL medolif(2D), ESTET-ASTRID(3D). From different tests we have deducted that the most appropriate model for the realization of CFB`s prediction is the model taking in account the influence of particles on fluid turbulence. Then, to evaluate the validity limits of this model, we have built the regime diagram, and we have compared it with the experimental diagram. We have concluded that the simulation allows to describe the different CFB`s working regimes, and especially transitions. We have also noticed the importance of the choice of the mean diameter of the simulated particles. In this way, making a correction of the simulated particles` diameter in comparison with Sauter mean particle diameter, we obtained numerical results in good agreement with experimental data. (authors) 13 refs.

  16. Study of the behaviour of gaseous pollutants during the incineration of municipal solid waste in a circulating fluidized bed; Etude du devenir des polluants gazeux lors de l`incineration d`ordures menageres en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Desroches-Ducarne, E.

    1997-09-30

    The Circulating Fluidized Bed (CFB) combustor seems to be a promising tool, being able to burn a variety of fuels whilst maintaining low emissions levels. The present work describes an experimental and theoretical investigation into the formation and destruction of acid gases (HCl and SO{sub 2}) and nitrogen oxides (NO and N{sub 2}O) during Municipal Solid Waste incineration. Experiments were conducted on six different fuels (namely MSW, mixtures of wood, paper, plastics, polyethylene...). The effect of five parameters (temperature, excess air, air staging, calcium addition and moisture) on the emissions levels was investigated. A statistical study on the experimental data allowed us to quantify the impact of the operating conditions and the influence of the fuel characteristics. A mathematical model has been developed which includes the main physical and chemical steps of combustion in CFB and which predicts the pollutant emissions under various operating conditions. A parametric study of the influence of operating conditions on emissions showed that in most cases the trends predicted by the model are in agreement with the experimental observations. (author) 175 refs.

  17. Formation and destruction mechanisms of nitrogen oxides during coal combustion in circulating fluidized beds; Mecanismes de formation et de destruction des oxydes d`azote lors de la combustion du charbon en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Borrel, G.; Lecuyer, I. [Universite du Haut-Rhin, 68 - Mulhouse (France)

    1997-01-01

    Formation and reduction of nitrogen oxides (NO and N{sub 2}O) during coal combustion in a circulating fluidized bed (CFBC) are very complicated and yet badly known. The aim of the present study was to better characterize these phenomena on a small-sized experimental unit (reactor diameter: 5 cm), with the possibility to re-inject the solids in the bottom of the furnace, as in a real industrial unit. This should allow then to develop a numerical set of chemical reactions involving the nitrogen oxides. The experimental results showed that coal ash plays a great role in reducing nitrogen oxides, the determining parameter being the quantity of unburnt carbon remaining in the ash. The study then detailed the interaction between nitrogen oxides and de-volatilized (char) according to the temperature, NO{sub x} concentration and the mass of solid. In the absence of oxygen small quantities of char can very significantly reduce NO as well as N{sub 2}O. It was possible to establish destruction kinetics on these particles, and orders of reaction could be determined versus the NO{sub x} concentration and the char particle mass (heterogeneous phase chemical reactions). Then, the coal pyrolysis study enabled to identify the products released during coal devolatilization and thermogravimetric analyses displayed several successive weight losses due CO, CO{sub 2} and CH{sub 4} releases, during a linear temperature increase. Lastly coal combustion was studied in the small pilot with variable experimental conditions. Using the previous experimental was studied in the small pilot with variable experimental conditions. Using the previous experimental results, a model was developed to calculate NO{sub x} concentrations during the coal combustion and validated. The NO and N{sub 2}O contents calculated are thoroughly correlated with the experimental data whatever the injection carbon/oxygen ratio is. (author) 96 refs.

  18. Experimental and predicted approaches for biomass gasification with enriched air-steam in a fluidised bed.

    Science.gov (United States)

    Fu, Qirang; Huang, Yaji; Niu, Miaomiao; Yang, Gaoqiang; Shao, Zhiwei

    2014-10-01

    Thermo-chemical gasification of sawdust refuse-derived fuel was performed on a bench-scale fluidised bed gasifier with enriched air and steam as fluidising and oxidising agents. Dolomite as a natural mineral catalyst was used as bed material to reform tars and hydrocarbons. A series of experiments were carried out under typical operating conditions for gasification, as reported in the article. A modified equilibrium model, based on equilibrium constants, was developed to predict the gasification process. The sensitivity analysis of operating parameters, such as the fluidisation velocity, oxygen percentage of the enriched air and steam to biomass ratios on the produced gas composition, lower heating value, carbon conversion and cold gas efficiency was investigated. The results showed that the predicted syngas composition was in better agreement with the experimental data compared with the original equilibrium model. The higher fluidisation velocity enhanced gas-solid mixing, heat and mass transfers, and carbon fines elutriation, simultaneously. With the increase of oxygen percentage from 21% to 45%, the lower heating value of syngas increased from 5.52 MJ m(-3) to 7.75 MJ m(-3) and cold gas efficiency from 49.09% to 61.39%. The introduction of steam improved gas quality, but a higher steam to biomass ratio could decrease carbon conversion and gasification efficiency owing to a low steam temperature. The optimal value of steam to biomass ratio in this work was 1.0. PMID:25265865

  19. Magnetic resonance studies of jets in a gas-solid fluidised bed

    Institute of Scientific and Technical Information of China (English)

    Meenal Pore; Lynn F. Gladden; John S. Dennis; Thusara C. Chandrasekera; Daniel J. Holland; Aining Wang; Fei Wang; Qussai Marashdeh; Michael D. Mantle; Andrew J. Sederman; Liang-Shih Fan

    2012-01-01

    Magnetic resonance imaging (MRI) has been used to study the behaviour of jets at the distributor of a 50 mm diameter fluidised bed of 0.5 mm diameter poppy seeds.Two perforated-plate distributors were examined,containing either 10 or 14 holes,each 1 mm diameter.Ultra-fast MR imaging was able to show the transient nature of the upper parts of the jets,where discrete bubbles are formed.Imaging in 3D showed that the central jets were the longest for flow rates below minimum fluidisation.Above minimum fluidisation,the outer jets,nearest the wall of the fluidised bed,arched inward towards the central axis.In this latter case,interpretation of the time-averaged 3D image required the use of ultra-fast MR imaging to identify the approximate height above the distributor at which discrete bubbles were formed.The apparently continuous void extending along the central axis above this height in the time-averaged 3D image was thus identified,using ultra-fast MR imaging,as representing the averaged paths of released bubbles.Time-averaged MR velocity mapping was also used to identify dead zones of stationary particles resting on the distributor between the jets.The dead zones could be observed when the superficial velocity of the gas approached minimum fluidisation,but they were smaller than those observed at lower gas superficial velocity.Comparable images of a single jet through 1.2 mm diameter poppy seeds from MRI and electrical capacitance volume tomography (ECVT) are also demonstrated.

  20. Process intensification by direct product sequestration from batch fermentations: application of a fluidised bed, multi-bed external loop contactor

    Science.gov (United States)

    Hamilton; Morton; Young; Lyddiatt

    1999-08-01

    A critical comparison has been made of the relative efficacy of the primary purification of an extracellular acid protease produced by the yeast Yarrowia lipolytica. The performance of conventional, discrete sequences of fermentation, broth clarification and fixed bed, anion exchange chromatography has been compared with fluidised bed adsorption directly interfaced with post-term fermentation broth and fluidised bed adsorption directly integrated with productive fermentations (so-called direct product sequestration; DPS). Advantages of the latter, in terms of the improved yield and molecular quality of the protease end product are discussed in terms of the design, assembly and operation of component parts of DPS devices and their generic application to other extracellular bioproducts of microbial fermentations. Copyright 1999 John Wiley & Sons, Inc.

  1. Residues characterisation from the fluidised bed combustion of East London's solid recovered fuel

    OpenAIRE

    Balampanis, Dimitris E.; Pollard, Simon J. T.; Simms, N; Longhurst, Philip J.; Coulon, Frederic; Villa, Raffaella

    2010-01-01

    Waste thermal treatment in Europe is moving towards the utilisation of the combustible output of mechanical, biological treatment (MBT) plants. The standardisation of solid recovered fuels (SRF) is expected to support this trend and increase the amount of the generated combustion residues. In this work, the residues and especially the fly ashes from the fluidised bed combustion (FBC) of East London’s NCV 3, Cl 2, and Hg 1 class SRF, are characterised. The following toxicity ...

  2. A simplified approach to the drying of solids in a batch fluidised bed

    Directory of Open Access Journals (Sweden)

    C. Srinivasakannan

    2002-07-01

    Full Text Available A simplified model for drying solids in the constant rate period in a batch fluidised bed was developed.It assumes the bed to be divided into dense and bubble phases with heat and mass transfer between the phases.The model predicts the constant-rate drying period, provided the fluid bed shape and material characteristics are known.The model is compared with experimental data reported in the literature covering a wide range of materials, gas flow rates, column diameters, material hold-ups, air temperatures and humidities.Model predictions compare satisfactorily with the experimental data.

  3. Melt granulation of pharmaceutical powders: a comparison of high-shear mixer and fluidised bed processes.

    Science.gov (United States)

    Passerini, Nadia; Calogerà, Giacomo; Albertini, Beatrice; Rodriguez, Lorenzo

    2010-05-31

    The main aim of this research was to compare in situ melt granulation process in high-shear mixers and fluidised bed equipments with particular attention to the final properties of granules. In addition, the study evaluated the suitability of melt granulation in fluidised bed for improving the dissolution rate of drugs. Agglomerates having identical composition (10%, w/w, of ibuprofen or ketoprofen, 20%, w/w, of PEG 6000 and 70%, w/w, of lactose monohydrate) were produced using both equipments and their morphology, particle size, flowability, friability, drug loading, dissolution behaviors at pH 1.2 and 7.4 and physicochemical properties (DSC and XRD analysis) have been evaluated and compared. The results showed that melt granulation can be successfully performed in both granulators. The utilization of a different equipment had strong impact on the particle size distribution of the granules and on their morphology, while the effect on others physical properties was little, as all the granules possess low friability and excellent flowability. Moreover both the solid state characteristics of the products and the dissolution behaviors of ibuprofen and ketoprofen granules were found to be practically independent of the equipment and all granules showed a significant increase of the drug dissolution rate in acidic conditions. In conclusion in situ melt granulation in fluidised beds could be considered a suitable alternative to the melt granulation in high-shear mixers. PMID:20214959

  4. Effect of bed temperature and bed composition on agglomeration during gasification of high-sodium, high-sulphur lignite in a spouted fluidised bed

    Energy Technology Data Exchange (ETDEWEB)

    D.P. McCullough; P.J. Mullinger; P.J. Ashman [University of Adelaide, Adelaide, SA (Australia). Cooperative Research Centre for Clean Power from Lignite, School of Chemical Engineering

    2003-07-01

    Fluidised bed gasification (FBG) is an alternative process for coal utilisation that delivers improved efficiencies and lower temperature operation compared to conventional technology. Agglomeration and defluidisation are phenomena that have the potential to occur within fluidised bed reactors, which can interrupt stable process operation. While extensive work has been carried out investigating fluidised bed combustion of lignite, relatively little work has been carried out for lignite under fluidised bed gasification conditions. Gasification of high sodium, high sulphur content lignite in a spouted bed gasifier (SBG) indicates that agglomeration and defluidisation is only an issue when maximum bed temperature exceeds approximately 850{degree}C and air/fuel ratios of 2.5 outside of these conditions, defluidisation is not detected. It is also demonstrated that defluidisation occurs before agglomeration, rather than as a result of agglomeration as previously thought. The Rosin-Rammler method of describing particle size distribution is found to yield appropriate variables for quantification of the extent of agglomeration taking place in cases where defluidisation is a factor. However, it has been shown by this method that while initial results indicated that agglomeration extent varies directly with maximum bed temperature, further results have shown that other variables, such as superficial velocity, have a significant impact on the extent of agglomeration. Investigations are currently continuing. 9 refs., 8 figs., 9 tabs.

  5. Model of fragmentation of limestone particles during thermal shock and calcination in fluidised beds

    Energy Technology Data Exchange (ETDEWEB)

    Saastamoinen, J.; Pikkarainen, T.; Tourunen, A.; Rasanen, M.; Jantti, T. [VTT Technical Research Center, Jyvaskyla (Finland)

    2008-11-15

    Fragmentation of limestone due to thermal shock and calcination in a fluidised bed was studied through experiments and modelling. The time for heating was estimated by model calculations and the time for calcination by measurements. Fragmentation due to thermal shock was carried out by experiments in a CO{sub 2} atmosphere in order to prevent the effect of calcination. It was found to be much less than fragmentation due to calcination. Average particle sizes before and after fragmentation are presented for several types of limestone. The effects of particle size and gas composition on the primary fragmentation were studied through experiments. Increasing the fluidisation velocity increased the tendency to fragment. The evolution of the particle size distribution (PSD) of limestone particles due to thermal shock and during calcination (or simultaneous calcination and sulphation) were calculated using a population balance model. Fragmentation due to thermal shock is treated as an instantaneous process. The fragmentation frequency during calcination is presented as exponentially decaying over time. In addition to the final PSD, this model also predicts the PSD during the calcination process. The fragmentation was practically found to end after 10 min. Furthermore. a population balance method to calculate the particle size distribution and amount of limestone in fluidised beds in dynamic and steady state, when feeding history is known, is presented.

  6. Gasification of biomass and coal in a pressurised fluidised bed gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Andries, J.; Jong, W. de; Hein, K.R.G. [Technische Univ. Delft (Netherlands)

    1998-09-01

    During a 3 year (1996-1998) multinational JOULE project, partly funded by the EU, experimental and theoretical research is being done on co-gasification of biomass (pelletised straw and Miscanthus) and coal in a pressurised fluidised bed reactor. The influence of feedstock and operating conditions on gasification characteristics has been studied using a 1.5 MW{sub th} gasifier, which has been operated at a pressure of 5 bar and temperatures up to 900 C. The project and the test rig are described and results obtained in the first part of the project are presented and analysed. (orig.)

  7. Hot waste-to-energy flue gas treatment using an integrated fluidised bed reactor

    International Nuclear Information System (INIS)

    This paper describes an innovative process to increase superheated steam temperatures in waste-to-energy (WTE) plants. This solution is mainly characterised by a fluidised bed reactor in which hot flue gas is treated both chemically and mechanically. This approach, together with gas recirculation, increases the energy conversion efficiency, and raises the superheated steam temperature without decreasing the useful life of the superheater. This paper presents new experimental data obtained from the test facility installed at the Hera S.p.A. WTE plant in Forli, Italy; discusses changes that can be implemented to increase the duration of experimental testing; offers suggestions for the design of an industrial solution

  8. Gas-particle interactions in dense gas-fluidised beds

    NARCIS (Netherlands)

    Li, Jie; Kuipers, J.A.M.

    2003-01-01

    The occurrence of heterogeneous flow structures in gas-particle flows seriously affects gas¿solid contacting and transport processes in dense gas-fluidized beds. A computational study, using a discrete particle method based on Molecular Dynamics techniques, has been carried out to explore the mechan

  9. Energy recovery from sewage sludge by means of fluidised bed gasification.

    Science.gov (United States)

    Gross, Bodo; Eder, Christian; Grziwa, Peter; Horst, Juri; Kimmerle, Klaus

    2008-01-01

    Because of its potential harmful impact on the environment, disposal of sewage sludge is becoming a major problem all over the world. Today the available disposal measures are at the crossroads. One alternative would be to continue its usage as fertiliser or to abandon it. Due to the discussions about soil contamination caused by sewage sludge, some countries have already prohibited its application in agriculture. In these countries, thermal treatment is now presenting the most common alternative. This report describes two suitable methods to directly convert sewage sludge into useful energy on-site at the wastewater treatment plant. Both processes consist mainly of four devices: dewatering and drying of the sewage sludge, gasification by means of fluidised bed technology (followed by a gas cleaning step) and production of useful energy via CHP units as the final step. The process described first (ETVS-Process) is using a high pressure technique for the initial dewatering and a fluidised bed technology utilising waste heat from the overall process for drying. In the second process (NTVS-Process) in addition to the waste heat, solar radiation is utilised. The subsequent measures--gasification, gas cleaning and electric and thermal power generation--are identical in both processes. The ETVS-Process and the NTVS-Process are self-sustaining in terms of energy use; actually a surplus of heat and electricity is generated in both processes. PMID:17919896

  10. Experimental validation of granular dynamics simulations of gas-fluidised beds with homogeneous inflow conditions using Positron Emission Particle Tracking

    NARCIS (Netherlands)

    Hoomans, B.P.B.; Kuipers, J.A.M.; Mohd Salleh, M.; Seville, J.P.

    2001-01-01

    A hard-sphere granular dynamics model of a two-dimensional gas-fluidised bed was experimentally validated using Positron Emission Particle Tracking (PEPT). In the model the Newtonian equations of motion are solved for each solid particle while taking into account the particle¿particle and particle¿w

  11. On suitability of novel fluidised bed technique for separation of metallic powders during commercial powder metallurgical processing

    NARCIS (Netherlands)

    Ritherdon, J; Dechsiri, C; Jones, AR; Hoffmann, AC; Wright, IG

    2005-01-01

    Experiments have been performed to test the efficiency with which a novel fluidised bed technique could separate different metallic powders in terms of size and density. The overall aim was to assess the potential of this technique for the commercial separation of defective powder fractions from mec

  12. Recommendations for conversions of grate fired boilers to fluidising beds; Anvisningar foer konvertering av rosterpannor till fluidiserad baeddteknik

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Lars; Ingman, Rolf [AaF Energikonsult AB, Stockholm (Sweden)

    2001-03-01

    This report gives advice and recommendations for retrofitting of grate fired boilers to fluidising beds. Nine plants have been visited and experiences from these conversion projects have been gathered and analysed. Among the important points planning, fuel specification, heat balance calculations and clarifying of delivery limits can be mentioned. It is also important not to underestimate the need for education of the operational staff.

  13. Alkali retention/separation during bagasse gasification: a comparison between a fluidised bed and a cyclone gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Gabra, M. [Lulea University of Technology (Sweden). Div. of Energy Engineering; Energy Technology Centre, Pitea (Sweden); Nordin, A. [Umea University (Sweden). Dept. of Inorganic Chemistry; Ohman, M. [Energy Technology Centre, Pitea (Sweden); Umea University (Sweden). Dept. of Inorganic Chemistry; Kjellstrom, B. [Lulea University of Technology (Sweden). Div. of Energy Engineering

    2001-12-01

    Biomass fuelled integrated gasification/gas turbines (BIG/GTS) have been found to be one of the most promising technologies to maximise electricity output in the sugar industry. However, biomass fuels contain alkali metals (Na and K) which may be released during the gasification processes and cause deleterious effects on the downstream hardware (e.g. the blades of gas turbines). Much research has therefore been focused on different kinds of gas cleaning. Most of these projects are using a fluidised bed gasifier and includes extensive gas cleaning which leads to a high capital investment. Increasing alkali retention/separation during the gasification may lead to improved producer gas quality and reduced costs for gas cleaning. However, very little quantitative information is available about the actual potential of this effect. In the present work, comparative bench-scale tests of bagasse gasification were therefore run in an isothermal fluidised bed gasifier and in a cyclone gasifier to evaluate which gasification process is most attractive as regards alkali retention/separation, and to try to elucidate the mechanisms responsible for the retention. The alkali retention in the fluidised bed gasifier was found to be in the range of 12-4% whereas in the cyclone gasifier the alkali separation was found to be about 70%. No significant coating of the fluidised bed's bed material particles could be observed. The SEM/EDS and the elemental maps of the bed material show that a non-sticky ash matrix consisting of mainly Si, AI and K were distributed in a solid form separated from the particles of bed material. This indicates the formation of a high temperature melting potassium containing silicate phase, which is continuously scavenged and lost from the bed through elutriation. (author)

  14. A new process control strategy for aqueous film coating of pellets in fluidised bed

    DEFF Research Database (Denmark)

    Larsen, C.C.; Sonnergaard, Jørn; Bertelsen, Pernille Scholdan;

    2003-01-01

    The parameters with effect on maximum spray rate and maximum relative outlet air humidity when coating pellets in a fluidised bed were investigated. The tested variables include type of water based modified release film coating (Eudragit® NE 30D, Eudragit® RS 30D, Aquacoat ECD®) coating principle...... (top spray, bottom spray), inlet air humidity and type of pellets (sugar spheres, microcrystalline cellulose pellets). The maximum spray rate was not influenced by the coating principles. The highest spray rate was obtained for the film polymer with the lowest tackiness which is assumed......-process calculation of degree of utilisation of the potential evaporation energy (DUE) of the outlet air and the relative outlet air humidity (RH). The spray rate is maximised using set points of DUE and RH as control parameters. The product temperature is controlled simultaneously by regulating the inlet air...

  15. Thermodynamic study of alkali metals release in pressurised fluidised-bed combustion and gasification of peat

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, W.; Backman, R.; Korhonen, M.

    1988-01-01

    A combined-cycle power generation system incorporating pressurised fluidised-bed combustion (PFBC) or gasification is considered a promising approach for electricity generation using solid fuels such as peat. In these systems, the high-pressure hot flue gas is expanded in a gas turbine. Peat contains sodium and potassium which are released in combustion and gasification. These are corrosive elements that can cause severe damage to the turbine blades if not suppressed. Multicomponent, multiphase equilibrium calculations were carried out for atmospheric and pressurised fluidised-bed operating conditions to determine the relative distribution of the two metals (Na and K) in the gas and condensed phases. Dependence of the alkali volatilisation on the operating temperature, pressure, the chlorine-content and the total alkali-content of the feedstock was studied. The results show that the alkali release in the vapour-phase could be much higher than acceptable to a gas turbine, particularly under gasification conditions. Hence the necessity to remove the volatilised alkali-metal compounds is more acute in gasification than in combustion. Both sodium and potassium are present as chlorides and to a lesser extent as hydroxides in the gas phase in both modes of operation (i.e. combustion and gasification). However, whereas under combustion conditions both metals seem to condense as sulphates (Na/sub 2/SO4 and K/sub 2/SO4), in gasification, chlorides and carbonates dominate in the condensed phase. The alkali-metals volatilisation shows strong dependence on the operating pressure of the system as well as on the chlorine-content of the feedstock. It decreases markedly with the former but increases sharply with the latter.

  16. Forest biomass waste combustion in a pilot-scale bubbling fluidised bed combustor

    International Nuclear Information System (INIS)

    Combustion experiments of forest biomass waste in a pilot-scale bubbling fluidised bed combustor were performed under the following conditions: i) bed temperature in the range 750-800 oC, ii) excess air in the range 10-100%, and iii) air staging (80% primary air and 20% secondary air). Longitudinal pressure, temperature and gas composition profiles along the reactor were obtained. The combustion progress along the reactor, here defined as the biomass carbon conversion to CO2, was calculated based on the measured CO2 concentration at several locations. It was found that 75-80% of the biomass carbon was converted to CO2 in the region located below the freeboard first centimetres, that is, the region that includes the bed and the splash zone. Based on the CO2 and NO concentrations in the exit flue gas, it was found that the overall biomass carbon conversion to CO2 was in the range 97.2-99.3%, indicating high combustion efficiency, whereas the biomass nitrogen conversion to NO was lower than 8%. Concerning the Portuguese regulation about gaseous emissions from industrial biomass combustion, namely, the accomplishment of CO, NO and volatile organic compounds (VOC) (expressed as carbon) emission limits, the set of adequate operating conditions includes bed temperatures in the range 750oC-800 oC, excess air levels in the range 20%-60%, and air staging with secondary air accounting for 20% of total combustion air.

  17. Comparison of coal/solid recovered fuel (SRF) with coal/refuse derived fuel (RDF) in a fluidised bed reactor.

    OpenAIRE

    Wagland, Stuart Thomas; Kilgallon, P.; Coveney, R.; Garg, A; Smith, Richard; Longhurst, Philip J.; Pollard, Simon J. T.; Simms, Nigel J

    2011-01-01

    An experimental study was undertaken to compare the differences between municipal solid waste (MSW) derived solid recovered fuel (SRF) (complying with CEN standards) and refuse derived fuel (RDF). Both fuels were co-combusted with coal in a 50kW fluidised bed combustor and the metal emissions were compared. Synthetic SRF was prepared in the laboratory by grinding major constituents of MSW such as paper, plastic, textile and wood. RDF was obtained from a local mechanical trea...

  18. Validation of the flux number as scaling parameter for top-spray fluidised bed systems

    DEFF Research Database (Denmark)

    Hede, Peter Dybdahl; Bach, P.; Jensen, Anker Degn

    2008-01-01

    2SO4 using Dextrin as binder in three top-spray fluidised bed scales, i.e. a small-scale (type: GEA Aeromatic-Fielder Strea-1), medium-scale (type: Niro MP-1) and large-scale (type: GEA MP-2/3). Following the parameter guidelines adapted from the original patent description, the flux number was...... tested in the preferred range of 3.5-4.5 as well as with a value of 4.7 in a total of 24 experiments. The agglomeration tendency was observed to decrease with increasing flux number on an overall basis, but coating conditions with flux number values below 4.5 resulted in a complete collapse of the bed....... Coating conditions with flux number values of 4.5 and 4.7 were however successful in terms of agglomeration tendency and match of particle size fractions, but indicated in addition a strong influence of nozzle pressure. The present paper suggests even narrower boundaries for the flux number compared to...

  19. Trace elements release during fluidised bed (co-)pyrolysis of sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Jaakko Savolahti; Loay Saeed; Ron Zevenhoven [Helsinki University of Technology, Espoo (Finland). Laboratory of Energy Engineering and Environmental Protection

    2006-07-01

    The objective of this work was to investigate the release of mercury (Hg) and other trace elements (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Tl, V, Zn, Ti and Se) from sewage sludge during pyrolysis in a laboratory scale bubbling fluidised bed reactor. Coal and coal-car tyre scrap was also co-pyrolysed with the sewage sludge. Mercury emissions were measured by the Ontario Hydro Method or by EON-developed dry sampling method. Other trace elements were sampled by directing the flue gas flow through a scrubber tank containing fifteen litres of HNO{sub 3}/H{sub 2}O{sub 2} liquid, from which samples were taken during the test. The compositions of bed sand, fuel and char were also analysed. FT-IR gas analysis was used to measure concentrations of about twenty gaseous species in the pyrolysis product gas. From our experiments it was found that all of the mercury was vaporised from the fuel already at temperatures below 300{sup o}C. The mercury was found to be almost exclusively in the elemental form. Se and As showed significant vaporisation behaviour. 14 refs., 4 figs., 4 tabs.

  20. Occurrence of bromine in fluidised bed combustion of solid recovered fuel

    Energy Technology Data Exchange (ETDEWEB)

    Vainikka, P.

    2011-12-15

    Corrosive ash species are the single most important factor limiting the electric efficiency of steam boiler plants fired with waste or biomass. Chlorine has been found to have a central role in the chemistry involved as it reduces the melting temperature of ash, forms corrosive vapour and gas species in the furnace and halogenated deposits on boiler heat transfer surfaces. In this context chlorine has been extensively researched. At the time of writing this thesis there was hardly any published data available on the occurrence of bromine (Br) in the aforementioned context. The objective of this work was to review the occurrence of bromine in solid fuels and characterise the behaviour of bromine in full-scale fluidised bed combustion. The review on the occurrence of bromine in solid fuels revealed that in anthropogenic wastes bromine is mainly found in connection to flame retarded substances. Several weight percentages of bromine can be found in plastics treated with brominated flame retardants (BFRs). Bromine is typically found some 100-200 mg kg-1 in mixed municipal solid wastes (MSW). Bromine may be enriched in fuels with high share of plastics, such as solid recovered fuel (SRF) or refuse derived fuel (RDF). Up to 2000 mg kg-1 was found as a monthly average in SRF, typical levels being 20-200 mg kg-1. Wastewater sludge from paper mills may contain bromine 20-100 mg kg-1 due the use of bromine based biocides. In other fuels bromine may be found in significant amounts in marine influenced coal deposits and peat as well as in biomass treated with brominated pesticides. In the experimental part SRF, spruce bark and wastewater sludge from a paper mill were co-fired in a full- scale bubbling fluidised bed (BFB) boiler, and the collected fuels, aerosols and waterwall deposits were analysed with the focus on the fate of bromine. Bromine was mainly found to form water soluble high vapour pressure alkali metal halides in the furnace - in the form of KBr(g) and NaBr(g) as

  1. Reactive Gas Solids Flow in Circulating Fluidised Beds

    DEFF Research Database (Denmark)

    Hjertager, Bjørn Helge; Solberg, Tron; Hansen, Kim Granly

    2005-01-01

    Progress in modelling and simulation of flow processes in gas/particle systems carried out at the authors? research group are presented. Emphasis is given to computational fluid dynamics (CFD) models that use the multi-dimensional multi fluid techniques. Turbulence modelling strategies for gas/pa...

  2. Thermal treatment of electronic waste in a fluidised bed and chemical digestion of solid products.

    Science.gov (United States)

    Woynarowska, Amelia; Żukowski, Witold; Żelazny, Sylwester

    2016-07-01

    The article presents the results of e-waste thermal treatment in a fluidised bed reactor and solid products digestion under acidic conditions. During the processes, measurements of carbon monoxide, carbon dioxide, volatile organic compounds, nitrogen oxides, sulphur dioxide, hydrogen chloride, hydrogen bromide, hydrogen cyanide, ammonia, phenol, aliphatic and aromatic hydrocarbons, hydrogen fluoride and phosgene were carried out. Several digestion tests of the solid residue in sulphuric acid (VI) at 25 °C-65 °C, for 55 min-24 h were conducted. In each case, the dilution method was used, i.e. preliminary digestion in concentrated sulphuric acid (VI) (95%) for 40 min, and then dilution to expected concentrations (30%-50%). Most preferred results were obtained using sulphuric acid (VI) with a target concentration of 40% at 65 °C, where the leaching degrees were 76.56% for copper, 71.67% for iron, 91.89% for zinc and 97.40% for tin. The time necessary to effectively carry out the digestion process was 220 min.

  3. Thermal treatment of electronic waste in a fluidised bed and chemical digestion of solid products.

    Science.gov (United States)

    Woynarowska, Amelia; Żukowski, Witold; Żelazny, Sylwester

    2016-07-01

    The article presents the results of e-waste thermal treatment in a fluidised bed reactor and solid products digestion under acidic conditions. During the processes, measurements of carbon monoxide, carbon dioxide, volatile organic compounds, nitrogen oxides, sulphur dioxide, hydrogen chloride, hydrogen bromide, hydrogen cyanide, ammonia, phenol, aliphatic and aromatic hydrocarbons, hydrogen fluoride and phosgene were carried out. Several digestion tests of the solid residue in sulphuric acid (VI) at 25 °C-65 °C, for 55 min-24 h were conducted. In each case, the dilution method was used, i.e. preliminary digestion in concentrated sulphuric acid (VI) (95%) for 40 min, and then dilution to expected concentrations (30%-50%). Most preferred results were obtained using sulphuric acid (VI) with a target concentration of 40% at 65 °C, where the leaching degrees were 76.56% for copper, 71.67% for iron, 91.89% for zinc and 97.40% for tin. The time necessary to effectively carry out the digestion process was 220 min. PMID:27245176

  4. Residues characterisation from the fluidised bed combustion of East London's solid recovered fuel.

    Science.gov (United States)

    Balampanis, D E; Pollard, S J T; Simms, N; Longhurst, P; Coulon, F; Villa, R

    2010-07-01

    Waste thermal treatment in Europe is moving towards the utilisation of the combustible output of mechanical, biological treatment (MBT) plants. The standardisation of solid recovered fuels (SRF) is expected to support this trend and increase the amount of the generated combustion residues. In this work, the residues and especially the fly ashes from the fluidised bed combustion (FBC) of East London's NCV 3, Cl 2, and Hg 1 class SRF, are characterised. The following toxicity indicators have been studied: leachable chlorine, organochlorides expressed as pentachlorobenzene and hexachlorobenzene, and the heavy metals Cu, Cr, Cd, Zn, Ni, and Pb. Furthermore the mineralogical pattern of the ashes has been studied by means of XRD and SEM-EDS. The results suggest that these SRF derived ashes have significantly lower quantities of Cu, Cd, Pb, Zn, leachable Cl, and organochlorides when compared to other literature values from traditional waste thermal treatment applications. This fact highlights the importance of modern separation technologies employed in MBT plants for the removal of components rich in metals and chlorine from the combustible output fraction of SRF resulting to less hazardous residues. PMID:20231082

  5. Steam gasification of various feedstocks at a dual fluidised bed gasifier: Impacts of operation conditions and bed materials

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, Christoph; Koppatz, Stefan; Hofbauer, Hermann [Vienna University of Technology, Institute of Chemical Engineering, Vienna (Austria)

    2011-03-15

    Gasification of biomass is an attractive technology for combined heat and power production as well as for synthesis processes such as production of liquid and gaseous biofuels. Dual fluidised bed (DFB) technology offers the advantage of a nearly nitrogen-free product gas mainly consisting of H{sub 2}, CO, CO{sub 2} and CH{sub 4}. The DFB steam gasification process has been developed at Vienna University of Technology over the last 15 years using cold flow models, laboratory units, mathematical modelling and simulation. The main findings of the experimental work at a 100-kW pilot scale unit are presented. Different fuels (wood pellets, wood chips, lignite, coal, etc.) and different bed materials (natural minerals such as olivine, limestones, calcites, etc. as well as modified olivines) have been tested and the influence on tar content as well as gas composition was measured and compared among the different components. Moreover, the influence of operating parameters such as fuel moisture content, steam/fuel ratio and gasification temperature on the product gas has been investigated. DFB steam gasification of solid biomass coupled with CO{sub 2} capture, the so-called absorption enhanced reforming (AER) process, is highlighted. The experiments in pilot scale led to commercial realisation of this technology in demonstration scale. Summarising, the DFB system offers excellent fuel flexibility to be used in advanced power cycles as well as in polygeneration applications. (orig.)

  6. Co-gasification of meat and bone meal with coal in a fluidised bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    E. Cascarosa; L. Gasco; G. Gea; J.L. Sanchez; J. Arauzo [Universidad de Zaragoza (Spain). Thermochemical Processes Group

    2011-08-15

    After the Bovine Spongiform Encephalopathy illness appeared, the meat and bone meat (MBM) produced from animal residues became an important waste. In spite of being a possible fuel due to its heating value (around 21.4 MJ/kg), an important fraction of the meat and bone meal is being sent to landfills. The aim of this work is to evaluate the co-gasification of low percentages of meat and bone meal with coal in a fluidised bed reactor as a potential waste management alternative. The effect of the bed temperature (800-900{sup o}C), the equivalence ratio (0.25-0.35) and the percentage of MBM in the solid fed (0-1 wt.%) on the co-gasification product yields and properties is evaluated. The results show the addition of 1 wt.% of MBM in a coal gasification process increases the gas and the liquid yield and decreases the solid yield at 900{sup o}C and 0.35 of temperature and equivalence ratio operational conditions. At operational conditions of 900{sup o}C and equivalence ratio of 0.35, the specific yield to gas (y{sub gas}) increases from 3.18 m{sup 3}(STP)/kg to 4.47 m{sup 3}(STP)/kg. The gas energy yield decreased 24.1% and the lower heating value of the gas decreases from 3.36 MJ/m{sup 3}(STP) to 2.16 MJ/m{sup 3}(STP). The concentration of the main gas components (H{sub 2}, CO and CO{sub 2}) hardly varies with the addition of MBM, however the light hydrocarbon concentrations decrease and the H{sub 2}S concentration increases at the higher temperature (900{sup o}C). 32 refs., 9 figs., 7 tabs.

  7. An Analytical Solution Applied to Heat and Mass Transfer in a Vibrated Fluidised Bed Dryer

    Energy Technology Data Exchange (ETDEWEB)

    Picado, Apolinar

    2011-07-01

    A mathematical model for the drying of particulate solids in a continuous vibrated fluidised bed dryer was developed and applied to the drying of grain wetted with a single liquid and porous particles containing multicomponent liquid mixtures. Simple equipment and material models were applied to describe the process. In the plug-flow equipment model, a thin layer of particles moving forward and well mixed in the direction of the gas flow was regarded; thus, only the longitudinal changes of particle moisture content and composition as well as temperature along the dryer were considered. Concerning the material model, mass and heat transfer in a single isolated particle was studied. For grain wetted with a single liquid, mass and heat transfer within the particles was described by effective transfer coefficients. Assuming a constant effective mass transport coefficient and effective thermal conductivity of the wet particles, analytical solutions of the mass and energy balances were obtained. The variation of both transport coefficients along the dryer was taken into account by a stepwise application of the analytical solution in space intervals with non-uniform inlet conditions and averaged coefficients from previous locations in the dryer. Calculation results were verified by comparison with experimental data from the literature. There was fairly good agreement between experimental data and simulation but the results depend strongly on the correlation used to calculate heat and mass transfer coefficients. For the case of particles containing a multicomponent liquid mixture dried in the vibrated fluidised bed dryer, interactive diffusion and heat conduction were considered the main mechanisms for mass and heat transfer within the particles. Assuming a constant matrix of effective multicomponent diffusion coefficients and thermal conductivity of the wet particles, analytical solutions of the diffusion and conduction equations were obtained. The equations for mass

  8. Liquid transportation fuels via large-scale fluidised-bed gasification of lignocellulosic biomass

    Energy Technology Data Exchange (ETDEWEB)

    Hannula, I.; Kurkela, E.

    2013-04-15

    With the objective of gaining a better understanding of the system design trade-offs and economics that pertain to biomass-to-liquids processes, 20 individual BTL plant designs were evaluated based on their technical and economic performance. The investigation was focused on gasification-based processes that enable the conversion of biomass to methanol, dimethyl ether, Fischer-Tropsch liquids or synthetic gasoline at a large (300 MWth of biomass) scale. The biomass conversion technology was based on pressurised steam/O2-blown fluidised-bed gasification, followed by hot-gas filtration and catalytic conversion of hydrocarbons and tars. This technology has seen extensive development and demonstration activities in Finland during the recent years and newly generated experimental data has also been used in our simulation models. Our study included conceptual design issues, process descriptions, mass and energy balances and production cost estimates. Several studies exist that discuss the overall efficiency and economics of biomass conversion to transportation liquids, but very few studies have presented a detailed comparison between various syntheses using consistent process designs and uniform cost database. In addition, no studies exist that examine and compare BTL plant designs using the same front-end configuration as described in this work. Our analysis shows that it is possible to produce sustainable low-carbon fuels from lignocellulosic biomass with first-law efficiency in the range of 49.6-66.7% depending on the end-product and process conditions. Production cost estimates were calculated assuming Nth plant economics and without public investment support, CO2 credits or tax assumptions. They are 58-65 euro/MWh for methanol, 58-66 euro/MWh for DME, 64-75 euro/MWh for Fischer-Tropsch liquids and 68-78 euro/MWh for synthetic gasoline. (orig.)

  9. Gaseous emissions in pressurised fluidised-bed combustion. Analysis and summary of the pilot experiments; Kaasumaiset paeaestoet paineistetussa leijukerrospoltossa. Koetulosten kaesittely ja yhteenveto

    Energy Technology Data Exchange (ETDEWEB)

    Korpela, T.; Hippinen, I.; Konkola, M. [Helsinki Univ. of Technology, Espoo (Finland)

    1996-12-01

    The influence of operating conditions on gaseous emissions in pressurised fluidised-bed combustion have been studied. The research objectives have been behaviour of sulphur absorbents and reduction of sulphur dioxide emissions, reduction of nitrogen oxide emissions, release of vapour-phase alkalimetals and carbon monoxide emissions. The sulphur capture capacities of calcium-based sorbents under PFBC conditions have been studied at a pressurised fluidised-bed reactor and at a pressurised thermogravimetric apparatus. The project has also connected results of the experimental PFBC at HUT/EVO. (author)

  10. Strategies to reduce gaseous KCl and chlorine in deposits during combustion of biomass in fluidised bed boilers

    Energy Technology Data Exchange (ETDEWEB)

    Kassman, Haakan

    2012-11-01

    Combustion of a biomass with an enhanced content of alkali and chlorine (Cl) can result in operational problems including deposit formation and superheater corrosion. The strategies applied to reduce such problems include co-combustion and the use of additives. In this work, measures were investigated in order to decrease the risk of superheater corrosion by reducing gaseous KCl and the content of chlorine in deposits. The strategies applied were sulphation of KCl by sulphur/sulphate containing additives (i.e. elemental sulphur (S) and ammonium sulphate (AS)) and co-combustion with peat. Both sulphation of KCl and capture of potassium (K) in ash components can be of importance when peat is used. The experiments were mainly performed in a 12 MW circulation fluidised bed (CFB) boiler equipped for research purposes but also in a full-scale CFB boiler. The results were evaluated by means of IACM (on-line measurements of gaseous KCl), conventional gas analysis, deposit and corrosion probe measurements and ash analysis. Ammonium sulphate performed significantly better than elemental sulphur. Thus the presence of SO{sub 3} (i.e. AS) is of greater importance than that of SO{sub 2} (i.e. S) for sulphation of gaseous KCl and reduction of chlorine in deposits. Only a minor reduction of gaseous KCl was obtained during co-combustion with peat although chlorine in the deposits was greatly reduced. This reduction was supposedly due to capture of K by reactive components from the peat ash in parallel to sulphation of KCl. These compounds remained unidentified. The effect of volatile combustibles on the sulphation of gaseous KCl was investigated. The poorest sulphation was attained during injection of ammonium sulphate in the upper part of the combustion chamber during the lowest air excess ratio. The explanation for this is that SO{sub 3} was partly consumed by side reactions due to the presence of combustibles. These experimental results were supported by modelling, although the

  11. Stabilization of ash from combustion of MSW in a fluidised bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    Steenari, Britt-Marie; Wilewska, Magda [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Environmental Inorganic Chemistry

    2004-06-01

    Due to restrictions against the land filling of combustible waste and directives from authorities that favour energy recovery from the waste, combustion of household waste is becoming more common. Even though combustion of MSW reduces the volume of waste to be handled by approximately 90%, it produces ash residues containing most of the metals present in the original fuel and a number of other species carried through the boiler or formed during combustion. The residues can be divided into three categories: 1. Stable, inert ash that can be utilised in, for example, construction applications 2. Ash that is stable enough to be land filled as nonhazardous waste 3. Ash that contains large amounts of soluble components and potentially toxic metal species. The regulations considering leaching of ash components set limits for the release of soluble salts and toxic metals. Some fly ashes show low leachability for metals but gives a salt release that is too close to the limit for total dissolved solids. Since fly ash from FBC boilers represent the largest volume of ash from these boilers there is a need for a simple and cheap treatment method that reduces the amount of soluble salts, i.e. NaCl, KCl etc, in the ash. After stabilisation, the ash is supposed to go into a more stable category. The aim of this project has been to investigate the applicability of a method to wash such an ash with water. The work included laboratory studies of the ash properties, the water washing process, filtration properties of the ash slurry and also tests of the method in pilot scale at a full scale boiler. This work has been concentrated towards the investigation of cyclone ash from a bubbling fluidised bed boiler in Lidkoeping fired with 100% household waste. Elemental composition of ash samples before and after washing/filtration was determined by AAS or ICP after a suitable dissolution of the sample. The mineralogy of ash samples was analysed using X-ray powder diffractometry. This method

  12. Stabilization of ash from combustion of MSW in a fluidised bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    Steenari, Britt-Marie; Wilewska, Magda [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Environmental Inorganic Chemistry

    2004-06-01

    Due to restrictions against the land filling of combustible waste and directives from authorities that favour energy recovery from the waste, combustion of household waste is becoming more common. Even though combustion of MSW reduces the volume of waste to be handled by approximately 90%, it produces ash residues containing most of the metals present in the original fuel and a number of other species carried through the boiler or formed during combustion. The residues can be divided into three categories: 1. Stable, inert ash that can be utilised in, for example, construction applications 2. Ash that is stable enough to be land filled as nonhazardous waste 3. Ash that contains large amounts of soluble components and potentially toxic metal species. The regulations considering leaching of ash components set limits for the release of soluble salts and toxic metals. Some fly ashes show low leachability for metals but gives a salt release that is too close to the limit for total dissolved solids. Since fly ash from FBC boilers represent the largest volume of ash from these boilers there is a need for a simple and cheap treatment method that reduces the amount of soluble salts, i.e. NaCl, KCl etc, in the ash. After stabilisation, the ash is supposed to go into a more stable category. The aim of this project has been to investigate the applicability of a method to wash such an ash with water. The work included laboratory studies of the ash properties, the water washing process, filtration properties of the ash slurry and also tests of the method in pilot scale at a full scale boiler. This work has been concentrated towards the investigation of cyclone ash from a bubbling fluidised bed boiler in Lidkoeping fired with 100% household waste. Elemental composition of ash samples before and after washing/filtration was determined by AAS or ICP after a suitable dissolution of the sample. The mineralogy of ash samples was analysed using X-ray powder diffractometry. This method

  13. Comparison between finite volume and lattice-Boltzmann method simulations of gas-fluidised beds: bed expansion and particle-fluid interaction force

    Science.gov (United States)

    Third, J. R.; Chen, Y.; Müller, C. R.

    2016-07-01

    Lattice-Boltzmann method (LBM) simulations of a gas-fluidised bed have been performed. In contrast to the current state-of-the-art coupled computational fluid dynamics-discrete element method (CFD-DEM) simulations, the LBM does not require a closure relationship for the particle-fluid interaction force. Instead, the particle-fluid interaction can be calculated directly from the detailed flow profile around the particles. Here a comparison is performed between CFD-DEM and LBM simulations of a small fluidised bed. Simulations are performed for two different values of the superficial gas velocity and it is found that the LBM predicts a larger bed expansion for both flowrates. Furthermore the particle-fluid interaction force obtained for LBM simulations is compared to the force which would be predicted by a CFD-DEM model under the same conditions. On average the force predicted by the CFD-DEM closure relationship is found to be significantly smaller than the force obtained from the LBM.

  14. Testing of downstream catalysts for tar destruction with a guard bed in a fluidised bed biomass gasifier at pilot plant scale

    Energy Technology Data Exchange (ETDEWEB)

    Aznar, M.P.; Frances, E.; Campos, I.J.; Martin, J.A.; Gil, J. [Saragossa Univ. (Spain). Dept. of Chemistry and Environment Engineering; Corella, J. [Complutense Univ. of Madrid (Spain). Dept. of Chemical Engineering

    1996-12-31

    A new pilot plant for advanced gasification of biomass in a fast fluidised bed is now fully operative at University of Saragossa, Spain. It is a `3rd generation` pilot plant. It has been built up after having used two previous pilot plants for biomass gasification. The main characteristic of this pilot plant is that it has two catalytic reactors connected in series, downstream the biomass gasifier. Such reactors, of 4 cm i.d., are placed in a slip stream in a by-pass from the main gasifier exit gas. The gasification is made at atmospheric pressure, with flow rates of 3-50 kg/in, using steam + O{sub 2} mixtures as the gasifying agent. Several commercial Ni steam-reforming catalyst are being tested under a realistic raw gas composition. Tar eliminations or destructions higher than 99 % are easily achieved. (orig.) 2 refs.

  15. Chemical and ecotoxicological characterization of ashes obtained from sewage sludge combustion in a fluidised-bed reactor

    International Nuclear Information System (INIS)

    In 1999, the DEECA/INETI and the UBiA/FCT/UNL started a researching project on the partition of heavy metals during the combustion of stabilised sewage sludge (Biogran[reg]), in a fluidised-bed reactor, and on the quality of the bottom ashes and fly ashes produced. This project was entitled Bimetal and was funded by the Portuguese Foundation for Science and Technology. In this paper only the results on the combustion of Biogran[reg]) are reported. The combustion process was performed in two different trials, in which different amounts of sewage sludge and time of combustion were applied. Several ash samples were collected from the bed (bottom ashes) and from two cyclones (first cyclone and second cyclone ashes). Sewage sludge, bed material (sand) and ash samples were submitted to the leaching process defined in the European leaching standard EN 12457-2. The eluates were characterized for a set of inorganic chemical species. The ecotoxicological levels of the eluates were determined for two biological indicators (Vibrio fischeri and Daphnia magna). The results were compared with the limit values of the CEMWE French Regulation. The samples were also ranked according to an index based on the chemical characterization of the eluates. It was observed an increase of the concentration of metals along the combustion system. The ashes trapped in the second cyclone, for both combustion trials, showed the highest concentration of metals in the eluates. Chemically, the ashes of the second cyclone were the most different ones. In the ecotoxicological point of view, the ecotoxicity levels of the eluates of the ashes, for both combustion cycles, did not follow the same pattern as observed for the chemical characterization. The ashes of the first cyclone showed the highest ecotoxicity levels for V. fischeri and D. magna. This difference on chemical and ecotoxicological results proves the need for performing both chemical and ecotoxicological characterizations of the sub

  16. Comparison of coal/solid recovered fuel (SRF) with coal/refuse derived fuel (RDF) in a fluidised bed reactor

    International Nuclear Information System (INIS)

    An experimental study was undertaken to compare the differences between municipal solid waste (MSW) derived solid recovered fuel (SRF) (complying with CEN standards) and refuse derived fuel (RDF). Both fuels were co-combusted with coal in a 50 kW fluidised bed combustor and the metal emissions were compared. Synthetic SRF was prepared in the laboratory by grinding major constituents of MSW such as paper, plastic, textile and wood. RDF was obtained from a local mechanical treatment plant. Heavy metal emissions in flue gas and ash samples from the (coal + 10% SRF) fuel mixture were found to be within the acceptable range and were generally lower than that obtained for coal + 10% RDF fuel mixture. The relative distribution of heavy metals in ash components and the flue gas stream shows the presence of a large fraction (up to 98%) of most of the metals in the ash (except Hg and As). Thermo-gravimetric (TG) analysis of SRF constituents was performed to understand the behaviour of fuel mixtures in the absence and presence of air. The results obtained from the experimental study will enhance the confidence of fuel users towards using MSW-derived SRF as an alternative fuel.

  17. NOx and N{sub 2}O emission characteristics from fluidised bed combustion of semi-dried municipal sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Saenger, M.; Werther, J.; Ogada, T. [Technical University Hamburg-Harburg, Hamburg (Germany). Chemical Engineering

    2001-01-01

    Incineration is one of the major methods for the disposal of sewage sludge. Currently, several plants are incinerating mechanically dewatered (wet) sludge (20-40 wt.% d.m.) or semi-dried sewage sludge (3-55 wt.% d.m.), although some plants burn dry sludge (with more than 80 wt.% d.m.). Whereas significant information is available on NOx and N{sub 2}O emissions characteristics of wet and dry sludge, not much has been reported on semi-dried sludge. This paper presents some of the results obtained from the combustion of semi-dried sludge in a semi-pilot scale fluidised bed combustor (150 mm in diameter and 9 m high) together with some measurements from a large-scale FBC incineration plant (7 m{sup 2} bed area, 9 m high and a capacity of 3 t/h dry sludge). The investigations have shown that semi-dried sludge exhibit emission characteristics which are similar to those of wet sludge. NOx decreases slightly whereas N{sub 2}O remains more or less the same with increase in oxygen concentrations. Just like wet sludge, staged combustion was not effective for the reduction of NOx and N{sub 2}O. However, increasing the freeboard temperature led to rapid reduction of N{sub 2}O and some NOx reduction was achieved using flue gas recycling technique. Comparison shows that the results from the test rig were more or less similar to those obtained from the large-scale plants. 28 refs., 14 figs., 2 tabs.

  18. Wall-to-bed heat transfer in circulating fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Fox, W.B.; Grewal, N.S.; Moen, D.A. [Univ. of North Dakota, Grand Forks, ND (United States). Mechanical Engineering Dept.

    1999-05-01

    Circulating fluidized beds (CFBs) have become increasingly important in recent years for coal combustion and gas-solid reactions. Here, heat transfer from the wall of a circulating fluidized bed to the fast bed suspension has been investigated for several materials. The range of investigation includes dense and dilute phase fast fluidization and pneumatic transport. The overall heat transfer coefficient was found to be a function mainly of cross-sectional average suspension density. Effects of superficial velocity and solids mass flux were obscured by their interrelationship to the suspension density. Two models from the literature are evaluated using present and published data.

  19. Cofiring of difficult fuels: The effect of Ca-based sorbents on the gas chemistry in fluidised bed combustion; Kalsiumpohjaisten lisaeaineiden vaikutus leijukerrospolton kaasukemiaan vaikeiden polttoaineiden sekapoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Aeijaelae, M.; Partanen, J.; Fabritius, M.; Elo, T.; Virta, A.K. [Imatran Voima Oy, Vantaa (Finland)

    1997-10-01

    The objective of this project is to establish the effects of Ca-based sorbents on sulphur, halogen and alkaline chemistry in fluidised bed combustion of difficult fuels, and to find out any restrictions on the use of these sorbents. The aim is to acquire sufficient knowledge to ensure the operational reliability of power plants and to minimise the emissions and costs of flue gas cleaning. The results enable the owner to anticipate necessary changes associated with slagging, fouling and emission control in the existing power plants, when there are plans to increase the range of fuels used. (orig.)

  20. Pressurised fluidised bed combustion: an alternative clean coal technology. La combustion en lecho fluido a presion, una alternativa de uso limpio del carbon en desarollo

    Energy Technology Data Exchange (ETDEWEB)

    Bencomo Perez-Zamora, V.; Menendez Perez, J.A.E. (ENDESA, Madrid (Spain))

    1988-11-01

    The primary aim of thistechnology is to reduce emissions of sulphur and nitrous oxides. Pilot plant tests have achieved a sulphur fixing rate of over 95%. Pressurised fluidised bed combustion also has advantages with regard to the emission of contaminants. Halogens, fluorine and chlorine, which in conventional combustion methods are released in the gases, to a large degree remain in the ash as do trace elements, such as arsenic, which usually vapourise at high temperatures in pulverised coal combustors. This technology also has a high output of between 38 and 40% net according to the type of coal used. 10 figs., 10 tabs.

  1. CO-COMBUSTION OF REFUSE DERIVED FUEL WITH COAL IN A FLUIDISED BED COMBUSTOR

    OpenAIRE

    W. A. Wan Ab Karim Ghani; Alias, A. B.; K.R.CLIFFE

    2009-01-01

    Power generation from biomass is an attractive technology which utilizes municipal solid waste-based refused derived fuel. In order to explain the behavior of biomass-fired fluidized bed incinerator, biomass sources from refuse derived fuel was co-fired with coal in a 0.15 m diameter and 2.3 m high fluidized bed combustor. The combustion efficiency and carbon monoxide emissions were studied and compared with those from pure coal combustion. This study proved that the blending effect had incre...

  2. Interactions between SO2 and NOx emissions in fluidised bed combustion of coal. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Lin, W.

    1994-01-01

    ;Contents: Introduction; The emissions of SO2 and NOx and their interactions in fluidized-bed combustion (FBC) of coal; SO2 and NOx emissions in FBC of coal: a literature survey; Oxidation of NH3 in a fixed bed; Oxidation of NH3: influence of SO2, CO and CO2; Modeling SO2 and NOx emissions in AFBC: a simple approach; Modeling SO2 and NOx emissions in CFBC; Modeling SO2 and NOx emissions in FBC: a fundamental approach; Optimization and Conclusions.

  3. Carbonation of Mg(OH){sub 2} in a pressurised fluidised bed for CO{sub 2} sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Fagerlund, J.

    2012-07-01

    To date, a number of methods to accelerate natural weathering or in other words increase the CO{sub 2} uptake rate of various minerals have been suggested; commonly this is known as mineral carbonation or CO{sub 2} mineralisation. A brief literature review of recently published articles in this field is presented, showing that the interest in mineral carbonation is increasing. However, it should be noted that mineral carbonation is only one option in a larger portfolio of various carbon dioxide capture and storage (CCS) alternatives. Unlike many other options, the CO{sub 2} mineralisation option considered in this thesis is largely founded on the possibility to utilise the exothermic nature of magnesium carbonation and based on this notion, it has been divided into three steps. The first two steps are energy demanding, while the third step is energy 'negative', and in theory, the source of the energy required in the first two steps. Unfortunately, however, the energy demanded by the first two steps, Mg extraction and Mg(OH){sub 2} production, is (currently) much higher than what could be generated by the subsequent Mg(OH){sub 2} carbonation step. Nevertheless, opportunities to reduce the energy intensity of the process in question are still being investigated, and while an energy-neutral carbonation process might be difficult to achieve, energy requirements can still be rendered industrially acceptable (and comparable to or even better than for other CCS methods). The main focus of this thesis lies with the third step, Mg(OH){sub 2} carbonation, which is performed using a pressurised fluidised bed (PFB). The elevated CO{sub 2} pressure conditions (typically approx 20 bar) allow for the carbonation reaction to take place at higher temperatures (typically approx 500 deg C) than otherwise due to thermodynamic constraints on carbonate stability. The increase in reaction rate as a function of temperature follows the Arrhenius equation of exponential increase

  4. CO-COMBUSTION OF REFUSE DERIVED FUEL WITH COAL IN A FLUIDISED BED COMBUSTOR

    Directory of Open Access Journals (Sweden)

    W. A. WAN AB KARIM GHANI

    2009-03-01

    Full Text Available Power generation from biomass is an attractive technology which utilizes municipal solid waste-based refused derived fuel. In order to explain the behavior of biomass-fired fluidized bed incinerator, biomass sources from refuse derived fuel was co-fired with coal in a 0.15 m diameter and 2.3 m high fluidized bed combustor. The combustion efficiency and carbon monoxide emissions were studied and compared with those from pure coal combustion. This study proved that the blending effect had increased the carbon combustion efficiency up to 12% as compared to single MSW-based RDF. Carbon monoxide levels fluctuated between 200-1600 ppm were observed when coal is added. It is evident from this research that efficient co-firing of biomass with coal can be achieved with minimum modification of existing coal-fired boilers.

  5. SIMULATION OF THE DRYING CHARACTERISTICS OF GROUND NEEM SEEDS IN A FLUIDISED BED

    OpenAIRE

    A. KUYE; C.O.C. Oko; S. N. NNAMCHI

    2007-01-01

    The neem seed is a good source of neem oil as well as insecticides and pesticides. The oil and insecticides can be extracted by two consecutive leaching of neem seed kernels with hexane and ethanol. This work presents a model for simulating the drying of neem seeds in a fluidized bed. Experimental values obtained from literature were used to validate the model prediction. The drying simulation results show that there was a good agreement between the experimental values and the corresponding m...

  6. Feasibility study - Lowered bed temperature in Fluidised Bed boilers for waste; Foerstudie - Saenkt baeddtemperatur i FB-pannor foer avfallsfoerbraenning

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik

    2009-01-15

    Waste incineration generally serves two purposes; 1) dispose of waste and 2) generation of heat and power. In the process of power production from waste fuels, the steam temperatures in super heaters are generally limited by the severe fouling and corrosion that occurs at elevated material temperatures, caused by high concentrations of alkali metals and chloride in the flue gas and fly ash. The overall aim of a continuation of present project is to determine if a reduced temperature of the bed zone in a fluidized bed waste incinerator reduces the amount of alkali chlorides in the flue gas. If so, a reduced bed temperature might enable increased steam temperature in super heaters, or, at unchanged steam temperature, improve the lifespan of the super heaters. The results from the project are of interest for plant owners wishing to improve performance of existing plants. The results may also be used to modify the design of future plants by boiler manufacturers. The aim of present pre-study was to determine how far the bed temperature can be reduced in a waste fired fluidized bed boiler in Boraas while maintaining a stable operation with sufficient combustion temperature in the freeboard to fulfil the directives of waste incineration. A continuation of the project will be based on the results from present study. The work is based on experiments at the test boiler. During the present study, no other measurements were performed apart from some sampling of bed material and ashes at different modes of operation. The experiments show that it is possible to alter the air and recycled flue gas in such a manner that the bed temperature is reduced from about 870 deg C to 700 deg C at 100% load and normal fuel mixture, while fulfilling the directive of 850 deg C at 2 seconds. Within normal variations of the fuel properties, however, the bed temperature increases to somewhat above 700 deg C if the fuel turns dry, while it falls below 650 deg C when the fuel turns wet. With

  7. 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.

  8. Cluster Dynamics in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-11-01

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

  9. 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

  10. The Modelling of Flat Fluidised Photoreactors.

    Science.gov (United States)

    Iatridis, D.

    Available from UMI in association with The British Library. The present research constitutes a systematic study towards the modelling and design of flat plate fluidised photoreactors. Light transmitted through a fluidised photoreactor (transmittance) and light reflected from the reactor (reflectance) have been measured by new optical techniques. These two important design variables were correlated with relevant fluidisation parameters. The average light transmittance was found to increase with bed expansion, the square root of particle diameter and inversely with bed thickness. On the other hand, the average light reflectance was found to decrease with bed height and particle diameter. The correlations found for light transmittance and reflectance with the fluidised parameters were tested with experimental data using two types of particles of different optical characteristics. The form of these correlations was not affected by the type of particles used. The light energy retained within a fluidised photoreactor, "light absorption", was evaluated by an energy balance from the measured values of light transmittance and reflectance. The light absorption data obtained were regressed for two different types of particles. For 13X zeolites the average light absorption by the bed was found to increase with the second power of bed height and the square root of particle diameter and reactor thickness. For Co-Mo-Al_2O _3 the average light absorption by the bed was found to increase with particle diameter and inversely with bed height. A theoretical study was made using the light energy retained within the reactor to promote a photochemical reaction of first order with respect to reactant concentration and to light absorption. The fluidised bed was treated as a single phase continuously stirred tank reactor (CSTR). The conversion of the reactant was found to increase with the light absorption and decrease with flow rate. This modelling approach may be extended to more complex

  11. Modeling biomass gasification in circulating fluidized beds

    Science.gov (United States)

    Miao, Qi

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

  12. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    张利斌; 李修伦

    2001-01-01

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

  13. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  14. 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.

  15. Transients in a circulating fluidized bed boiler

    Science.gov (United States)

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

    2013-11-01

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

  16. CIRCULATING MOVING BED COMBUSTION PROOF OF CONCEPT

    Energy Technology Data Exchange (ETDEWEB)

    Jukkola, Glen

    2010-06-30

    Circulating Moving Bed (CMB) combustion technology has its roots in traditional circulating fluidized bed technology and involves a novel method of solid fuel combustion and heat transfer. CMB technology represents a step change in improved performance and cost relative to conventional PC and FBC boilers. The CMB heat exchanger preheats the energy cycle working fluid, steam or air, to the high temperature levels required in systems for advanced power generation. Unique features of the CMB are the reduction of the heat transfer surfaces by about 60% as a result of the enhanced heat transfer rates, flexibility of operation, and about 30% lower cost over existing technology. The CMB Phase I project ran from July 2001 through March 2003. Its objective was to continue development of the CMB technology with a series of proof of concept tests. The tests were conducted at a scale that provided design data for scale up to a demonstration plant. These objectives were met by conducting a series of experiments in ALSTOM Power’s Multi-use Test Facility (MTF). The MTF was modified to operate under CMB conditions of commercial interest. The objective of the tests were to evaluate gas-to-solids heat transfer in the upper furnace, assess agglomeration in the high temperature CMB bubbling bed, and evaluate solids-to-tube heat transfer in the moving bed heat exchanger. The Phase I program results showed that there are still some significant technical uncertainties that needed to be resolved before the technology can be confidently scaled up for a successful demonstration plant design. Work remained in three primary areas: • scale up of gas to solid heat transfer • high temperature finned surface design • the overall requirements of mechanical and process design. The CMB Phase II workscope built upon the results of Phase I and specifically addressed the remaining technical uncertainties. It included a scaled MTF heat transfer test to provide the necessary data to scale up gas

  17. 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.

  18. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-01-01

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

  19. Mineralogical and elemental composition of fly ash from pilot scale fluidised bed combustion of lignite, bituminous coal, wood chips and their blends

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaos Koukouzas; Jouni Hamalainen; Dimitra Papanikolaou; Antti Tourunen; Timo Jantti [Institute for Solid Fuels Technology and Applications, Ptolemais (Greece). Centre for Research and Technology Hellas

    2007-09-15

    The chemical and mineralogical composition of fly ash samples collected from different parts of a laboratory and a pilot scale CFB facility has been investigated. The fabric filter and the second cyclone of the two facilities were chosen as sampling points. The fuels used were Greek lignite (from the Florina basin), Polish coal and wood chips. Characterization of the fly ash samples was conducted by means of X-ray fluorescence (XRF), inductive coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA), particle size distribution (PSD) and X-ray diffraction (XRD). According to the chemical analyses the produced fly ashes are rich in CaO. Moreover, SiO{sub 2} is the dominant oxide in fly ash with Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} found in considerable quantities. Results obtained by XRD showed that the major mineral phase of fly ash is quartz, while other mineral phases that are occurred are maghemite, hematite, periclase, rutile, gehlenite and anhydrite. The ICP-OES analysis showed rather low levels of trace elements, especially for As and Cr, in many of the ashes included in this study compared to coal ash from fluidised bed combustion in general. 23 refs., 3 figs., 5 tabs.

  20. Investigations into the control of agglomeration and defluidisation during fluidised-bed combustion of low-rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Vuthaluru, H.B.; Linjewile, T.M.; Zhang, D.; Manzoori, A.R. [University of Adelaide, Adelaide, SA (Australia). Dept. of Chemical Engineering

    1999-03-01

    A laboratory scale spouted bed combustor was used to study the effectiveness of various control methodologies in alleviating ash-related problems such as particle agglomeration and bed defluidisation during bed combustion of low-rank coals. The three control techniques investigated are: (1) the use of mineral additives; (2) alternative bed materials; and (3) pretreatment of coal. Mineral additives including dolomite, two clays and gibbsite, were injected into the spouted bed combustor while burning a South Australian low-rank coal at 800{degree}C. Samples of the same coal treated with Al, water washing and acid washing were also tested in the spouted bed combustor. In addition, experiments were also conducted with alternative bed materials including bauxite and calcined sillimanite. Experiments showed that the three techniques reported in this paper are effective to different extents in reducing particle agglomeration and defluidisation. Among the mineral additives tested, gibbsite and a clay additive rich in kaolinite and sillimanite were found to be most effective. The use of calcined sillimanite and bauxite as alterative bed materials extended the combustion time before defluidisation occurred by 7 and 10 times, respectively, compared to silica sand. While A1 pretreatment and water-washing were found effective for control of agglomeration and defluidisation, acid-washing did not improve the operation of the bed burning this particular coal. Al enrichment in ash coating of bed particles which suppress the formation of Na and S rich eutectics was identified as the main mechanism for prevention of agglomeration and defluidisation by these control techniques. 10 refs., 4 figs., 3 tabs.

  1. The development and use of a laboratory scale reactor to study aspects of gasification in an air blown fluidised bed

    Energy Technology Data Exchange (ETDEWEB)

    Cousins, A.; Zhuo, Y.; Reed, G.P.; Paterson, N.; Dugwell, D.R.; Kandiyoti, R. [Imperial College London, London (United Kingdom). Dept of Chemical Engineering

    2006-07-01

    A laboratory scale reactor has been used to study aspects of air blown, spouted bed gasifiers. The effects of operating conditions on the release of fuel-N has been studied using both coal and sewage sludge. The work has clarified the reactions involved and shown that steam has an important effect on the formation of NH{sub 3} from both volatile-N and char-N. The HCN concentration depends strongly on the residence time at temperature and on the presence (and depth) of a char bed. Trace element results indicate that bed temperatures above 900{sup o}C enhanced depletion of Ba, Pb and Zn from the bed residue and their enrichment in the fines. Mercury and selenium were released and their subsequent capture required low temperature filters operating below 120{sup o}C. The reactor was modified to enable char samples to be prepared and collected under controlled conditions. Results show the decreasing reactivity of the char with increasing temperature, time, pressure and particle size. There appears to be an initial decrease in reactivity during pyrolysis and a further longer- term decrease caused by graphitisation. 10 refs., 8 figs., 6 tabs.

  2. Effect of pressure on gas-solid flow behavior in dense gas-fluidised beds: a discrete particle simulation study

    NARCIS (Netherlands)

    Li, Jie; Kuipers, J.A.M.

    2002-01-01

    A computational study has been carried out to assess the influence of pressure on the flow structures and regime transitions in dense gas-fluidized beds using the discrete particle simulation (DPS) approach. By employing particle level simulation, the particle–particle–fluid interactions were analyz

  3. Use of activated carbon and natural zeolite as support materials, in an anaerobic fluidised bed reactor, for vinasse treatment.

    Science.gov (United States)

    Fernández, N; Fdz-Polanco, F; Montalvo, S J; Toledano, D

    2001-01-01

    In Cuba, the alcohol distillation process from cane sugar molasses, produces a final waste (vinasse), with an enormous polluting potential and a high sulfate content. Applying the anaerobic technology, most of the biodegradable organic matter can turn into biogas, rich in methane but with concentrations of sulfide above 1%. The present work develops two experiences with anaerobic fluidized bed reactors (AFBR) using both Cuban raw material, activated carbon and natural zeolite, as support media, with the purpose of obtaining high organic matter removal rates and keeping sulfide and ammonium concentrations in the permissible ranges. The reactors were operated during 120 days, achieving an organic loading rate of 10 kg COD/m3 day, with COD removal above 70%, and a methane production of 2 L/d. The activated carbon and natural zeolite used support materials in anaerobic fluidized bed reactors, and showed good results of distillery waste removal. PMID:11575071

  4. Investigation of coalescence kinetics of microcristalline cellulose in fluidised bed spray agglomeration: experimental studies and modelling approach

    Directory of Open Access Journals (Sweden)

    M. Peglow

    2005-06-01

    Full Text Available In this paper a model for fluidized bed spray agglomeration is presented. To describe the processes of heat and mass transfer, a physical based model is derived. The model takes evaporation process from the wetted particles as well as the effects of transfer phenomena between suspension gas and bypass gas into account. The change of particle size distribution during agglomeration, modeled by population balances, is linked to the heat and mass transfer model. A new technique is derived to extract agglomeration and nucleation rates from experimental data. Comparisons of experiments and simulations are presented.

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

    Institute of Scientific and Technical Information of China (English)

    乔锐; 吕俊复; 刘青; 吴学安; 岳光溪

    2001-01-01

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

  6. 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.

  7. Multi-stage circulating fluidized bed syngas cooling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guohai; Vimalchand, Pannalal; Guan, Xiaofeng; Peng, WanWang

    2016-10-11

    A method and apparatus for cooling hot gas streams in the temperature range 800.degree. C. to 1600.degree. C. using multi-stage circulating fluid bed (CFB) coolers is disclosed. The invention relates to cooling the hot syngas from coal gasifiers in which the hot syngas entrains substances that foul, erode and corrode heat transfer surfaces upon contact in conventional coolers. The hot syngas is cooled by extracting and indirectly transferring heat to heat transfer surfaces with circulating inert solid particles in CFB syngas coolers. The CFB syngas coolers are staged to facilitate generation of steam at multiple conditions and hot boiler feed water that are necessary for power generation in an IGCC process. The multi-stage syngas cooler can include internally circulating fluid bed coolers, externally circulating fluid bed coolers and hybrid coolers that incorporate features of both internally and externally circulating fluid bed coolers. Higher process efficiencies can be realized as the invention can handle hot syngas from various types of gasifiers without the need for a less efficient precooling step.

  8. Propylene polymerization in a circulating slugging fluidized bed reactor

    NARCIS (Netherlands)

    Putten, van Inge Cornelia

    2004-01-01

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

  9. Circulating fluidized bed biological reactor for nutrients removal

    Institute of Scientific and Technical Information of China (English)

    Yubo CUI; Hongbo LIU; Chunxue BAI

    2008-01-01

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

  10. Circulating fluidized bed coal-saving optimization control method

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  11. Combustion of Jordanian oil shale using circulating fluidized bed

    International Nuclear Information System (INIS)

    this study re[resents design and manufacturing of a lab-scale circulating fluidized bed (C.F.B) to burn low grade fuel such as Jordanian oil shale. Hydrodynamic properties of C.F.B. were studied like minimum fluidization velocity, circulation flux and carryover rate. a hot run was firstly conducted by the combustion of L.P.G. to start up the combustion process. It proceeds until reaching the minimum burning temperature of oil shale particles, at which time the LPG supply was gradually reduced and oil shale feeding started. soon after reaching a self sustainable condition of oil shale particles, the LPG supply was cut off. The main combustion variables were investigated such as air to fuel ratios, temperature profiles across the bed, exhaust gas analysis and combustion efficiency. a combustion intensity of 859 kg/hr.m2 and combustion efficiency of 96% were achieved. (authors). 19 refs., 9 tab., 18 fig

  12. 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

  13. Parametric Study of NOx Emissions in Circulating Fluidized Bed Combustor

    International Nuclear Information System (INIS)

    Fluidized bed combustion behavior of coal and biomass is of practical interest due to its significant involvement in heating systems and power plant operations. This combustion behavior has been studied by many experimental techniques. . Use of biomass in coal-fired power plants results in high efficiencies and fuel diversity. Co-combustion experiments were carried out in a pilot scale test facility of circulating fluidized bed combustor (70KW). Effect of operating parameters on the NOx emissions is studied while burning coal with wheat straw. Relation between NOx emissions and operating parameters like bed temperature, excess air ratio, air staging, Ca/S molar ratio and fluidizing air velocity have been studied and discussed. (author)

  14. Cold-Flow Circulating Fluidized-Bed Identification

    Energy Technology Data Exchange (ETDEWEB)

    Parviz Famouri

    2005-07-01

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

  15. A Three-Dimensional Numerical Study of Gas-Particle Flow and Chemical Reactions in Circulating Fluidised Bed Reactors

    DEFF Research Database (Denmark)

    Hansen, Kim Granly

    shows good agreement. The 3D representation of the reactor geometry gives better predictions of the radial variation in concentration than in a similar 2D simulation, Samuelsberg and Hjertager (1995). A parameter study is performed to investigate improvements in the predicted pressure drop profile. When...

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

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

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

  17. 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.)

  18. 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

  19. Olive cake combustion in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Topal, H.; Durmaz, A. [Gazi Univ, Ankara (Turkey). Dept. of Mechanical Engineering; Atimtay, A.T. [Middle East Technical Univ., Ankara (Turkey). Dept. of Environmental Engineering

    2002-07-01

    This paper presents the results of a study in which an environmentally sound technology was developed for biomass usage for energy production in Turkey. A circulating fluidized bed of 125 mm diameter and 1,800 mm height was used to determine the combustion characteristics of olive cake (OC) produced in Turkey. Olive cake, an olive oil milling waste product, is available in large amounts at a very low cost. Efficient use of OC in energy production solves the problem of waste management and contributes to meeting targets of the Kyoto Protocol. In this study, olive cake alone and olive cake plus lignite mixtures were burned in separate experiments and in various ratios. A new feeding mechanism was developed to feed the olive cake to the bed. On-line concentrations of oxygen, sulphur dioxide, carbon dioxide, carbon monoxide, nitrogen oxides and total hydrocarbons were measured in the flue gas along with temperature distribution in the bed. Emissions were compared with national standards and combustion efficiency of the olive cake plus lignite coal mixtures and olive cake alone were calculated. The optimum operating parameters were described. OC burned with 94 to 98.5 per cent efficiency. The combustion efficiency increased with increased excess air ratio because volatiles released from the fuel were burned more completely. 3 refs., 5 tabs., 6 figs.

  20. Mathematical simulation of working processes in the furnace of a circulating fluidized bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    V.A. Dvoinishnikov; A.V. Larkov [Moscow Power Engineering Institute, Moscow (Russian Federation)

    2009-01-15

    A software system developed for simulating and calculating boiler furnaces with circulating fluidized beds is described. The main principles on which the system is constructed are outlined, and the physical and mathematical models of processes in circulating fluidized bed furnaces are described together with the calculation algorithm. Results from a study of analyzing the effect the grinding fineness of initial fuel particles has on the processes in a circulating fluidized bed furnace are presented.

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

  2. 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.

  3. INVESTIGATION INTO MALDISTRIBUTION IN A CIRCULATING FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Qingjie Guo; Joachim Werther; Ernst-Ulrich Hartge

    2003-01-01

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

  4. 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.

  5. Olive cake combustion in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Huseyin Topal; Aysel T. Atimtay; Ali Durmaz [Gazi University, Ankara (Turkey). Department of Mechanical Engineering, Engineering and Architecture Faculty

    2003-06-01

    In this study, a circulating fluidized bed of 125 mm diameter and 1800 mm height was used to find the combustion characteristics of olive cake (OC) produced in Turkey. A lignite coal that is most widely used in Turkey was also burned in the same combustor. The combustion experiments were carried out with various excess air ratios. The excess air ratio, {lambda} has been changed between 1.1 and 2.16. Temperature distribution along the bed was measured with thermocouples. On-line concentrations of O{sub 2}, SO{sub 2}, CO{sub 2}, CO, NOx and total hydrocarbons were measured in the flue gas. Combustion efficiencies of OC and lignite coal are calculated, and the optimum conditions for operating parameters are discussed. The combustion efficiency of OC changes between 82.25 and 98.66% depending on the excess air ratio. There is a sharp decrease observed in the combustion losses due to hydrocarbons and CO as the excess air ratio increases. The minimum emissions are observed at {lambda} = 1.35. Combustion losses due to unburned carbon in the bed material do not exceed 1.4 wt% for OC and 1.85 wt% for coal. The combustion efficiency for coal changes between 82.25 and 98.66% for various excess air ratios used in the study. The ash analysis for OC is carried out to find the suitability of OC ash to be used as fertilizer. The ash does not contain any hazardous metal. 7 refs., 10 figs., 6 tabs.

  6. 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...

  7. Experimental Study on an On-Line Measurement of High Temperature Circulating Ash Flux in a Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    Lu Xiaofeng; Li Yourong

    2001-01-01

    A new kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the principle of thermal equilibrium. A series of cold tests and hot tests were carried to optimize the structure and collocation of water-cooling tubes and showed that the method had the advantage of simple, accurate, reliable and good applicability for on-line usage in a circulating fluidized bed boiler.

  8. Comprehensive Mathematical Model for Coal Combustion in a Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    金晓钟; 吕俊复; 杨海瑞; 刘青; 岳光溪; 冯俊凯

    2001-01-01

    Char combustion is on a special reducing condition in the dense bed of a circulating fluidized bedcombustor. Experimental findings were used to develop a comprehensive mathematical model to simulate thehydrodynamic and combustion processes in a circulating fluidized bed combustor. In the model, gas-solidinteraction was used to account for the mass transfer between the bubble phase and the emulsion phase in thedense bed, which contributes to the reducing atmosphere in the dense bed. A core-annular structure wasassumed in the dilute area rather than a one-dimensional model. The submodels were combined to build thecomprehensive model to analyze the combustion in a circulating fluidized bed combustor and the effect ofoperating parameters on the coal combustion. The model predictions agree well with experimental results.

  9. Axial Liquid Dispersion in Gas-Liquid-Solid Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    M.Vatanakul; 孙国刚; 郑莹; M.Couturier

    2005-01-01

    The effects of liquid viscosities, solid circulating rates, liquid and gas velocities and phase holdups on the axial dispersion coefficient, Dax, were investigated in a gas-liquid-solid circulating fluidized bed (GLSCFB).Liquid viscosity promotes the axial liquid backmixing when solid particles and gas bubbles are present. Increases in gas velocities and solid circulating rates lead to higher Dax. The effects of liquid velocity on Dax are associated with liquid viscosity. Compared with conventional expanded beds, the GLSCFBs hold less axial liquid dispersion,approaching ideal plug-flow reactors.

  10. A Mathematical Model for Differential—Velocity Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    LiZhao; XiangdongXu

    1999-01-01

    The scheme of differential-velocity circulating fluidized bed was put forward by Thermal Engineering Department of Tsinghua university in 1992 and got patent simultaneously.An internal bed material circulation in combustor can be established by the discrepancy of entrainment at different air velocity,and separates the combustor into three different velocity regions,which constitutes the differential-velocity inside circulation.Mathematical modeling and simulation may facilitate understanding,Development and operation of this new process.Here cell model method was adopted to set up the model.

  11. Destruction and formation of PCDD/Fs in a fluidised bed combustor co-incinerating automotive shredder residue with refuse derived fuel and wastewater treatment sludge.

    Science.gov (United States)

    Van Caneghem, J; Vermeulen, I; Block, C; Van Brecht, A; Van Royen, P; Jaspers, M; Wauters, G; Vandecasteele, C

    2012-03-15

    During an eight day trial automotive shredder residue (ASR) was added to the usual waste feed of a Fluidized Bed Combustor (FBC) for waste-to-energy conversion; the input waste mix consisted of 25% ASR, 25% refuse-derived fuel (RDF) and 50% wastewater treatment (WWT) sludge. All inputs and outputs were sampled and the concentration of the 17 PCDD/Fs with TEF-values was determined in order to obtain "PCDD/F fingerprints". The ASR contained approximately 9000 ng PCDD/Fs/kg(DW), six times more than the RDF and 10 times more than the WWT sludge. The fingerprint of ASR and RDF was dominated by HpCDD and OCDD, which accounted for 90% of the total PDDD/F content, whereas the WWT sludge contained relatively more HpCDFs and OCDF (together 70%). The flue gas cleaning residue (FGCR) and fly and boiler ash contained approximately 30,000 and 2500 ng PCDD/Fs/kg(DW), respectively. The fingerprints of these outputs were also dominated by HpCDFs and OCDF. The bottom ash contained only OCDD and OCDF, in total 8 ng PCDD/Fs/kg (DW). From the comparison of the bottom ash fingerprints with the fingerprints of the other output fractions and of the inputs, it could be concluded that the PCDD/Fs in the waste were destroyed and new PCDD/Fs were formed in the post combustion process by de novo synthesis. During the ASR-co-incineration, the PCDD/F congener concentrations in the fly and boiler ash, FGCR and flue gas were 1.25-10 times higher compared to the same output fractions generated during incineration of the usual waste mix (70% RDF and 30% WWT sludge). The concentration of the higher chlorinated PCDD/Fs increased most. As these congeners have the lowest TEF-factors, the total PCDD/F output, expressed in kg TEQ/year, of the FBC did not increase significantly when ASR was co-incinerated. Due to the relatively high copper levels in the ASR, the copper concentrations in the FBCs outputs increased. As copper catalysis the de novo syntheses, this could explain the increase in PCDD

  12. Properties of Concrete Incorporating Bed Ash from Circulating Fluidized Bed Combustion and Ground Granulates Blast-furnace Slag

    Institute of Scientific and Technical Information of China (English)

    CHENG An; HSU Hui-Mi; CHAO Sao-Jeng

    2011-01-01

    The properties of concrete incorporating circulating fluidized bed combustion (CFBC) bed ash and ground granulates blast-furnace slag (GGBS) were studied. Compressive strength,drying shrinkage, mercury intrusion porosimetry (MIP), scanning electronic microscopy (SEM), and X-ray diffraction (XRD) of concrete samples containing CFBC bed ash and GGBS were used. This work used initial surface absorption test (ISAT) and rapid chloride penetration test (RCPT) on concrete to measure the absorption and the ability of concrete to resist chloride ion characteristics for different concrete samples containing CFBC bed ash and GGBS. Open circuit potential (OCP), direct current polarization resistance were obtained to evaluate rebar corrosion. The CFBC bed ash was X-ray amorphous and consist of SiO2, A12O3 and CaO compounds. As the replacement of CFBC for sand increases, the rate of initial surface absorption (ISA) increases but compressive strength decreases.When the content of CFBC bed ash replacement for sand maintains constant, the replacement of GGBS for cement increases, compressive strength increases but the rate of ISA decreases. Chloride and corrosion resistance of rebar significantly improve by utilizing a proper amount of CFBC bed ash and GGBS in concrete.

  13. Circulating hyaluronate: concentration in different vascular beds in man

    DEFF Research Database (Denmark)

    Bentsen, K D; Henriksen, Jens Henrik Sahl; Laurent, T C

    1986-01-01

    The plasma concentration of hyaluronate (hyaluronic acid; HA) was measured in different vascular beds in order to determine regional kinetics of endogenous HA in fasting, supine subjects with normal (n = 6) or moderately decreased kidney function (n = 9). In both groups hepatic venous HA was...

  14. Application of fluidised particles as turbulence promoters in ultrafiltration Improvement of flux and rejection

    NARCIS (Netherlands)

    Noordman, T.R.; Jonge, de A.; Wesselingh, J.A.; Bel, W.; Dekker, M.; Voorde, ter E.; Grijpma, S.D.

    2002-01-01

    To prevent fouling of ultrafiltration membranes during processing of protein solutions, a high degree of turbulence should be introduced in the feed solution, keeping the energy consumption as low as possible. For this purpose, the application of fluidised beds at the upstream side of the membrane c

  15. 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.)

  16. RADIAL PROFILE OF THE SOLID FRACTION IN A LIQUID-SOLID CIRCULATING FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Tiefeng Wang; Jinfu Wang; Jing Lin; Yong Jin

    2003-01-01

    @@ Liquid-solid circulating fluidized beds have a number of attractive features suitable for processes where liquid-solid contact is important (Liang et al., 1996; Zhang et al., 2002).Liang et al. (1996) and Zheng et al. (2002) studied the radial profile of the solid fraction in the liquid-solid circulating fluidization regime and found that it is not uniform, unlike the conventional liquid-solid fluidized bed. This non-uniformity can affect reactant concentration distribution, mass transfer and ultimately reactant conversion.Therefore, information on the radial flow structure is crucial to reactor design and process optimization.

  17. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Hengzhi Chen; Dawei Yang; Hongzhong Li; Shiyu Tan

    2006-01-01

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

  19. Prediction of the particle circulation rate in a draft tube spouted bed suspension dryer

    OpenAIRE

    ZORANA LJ. ARSENIJEVIC; ZELJKO B. GRBAVCIC; RADMILA V. GARIC-GRULOVIC

    2006-01-01

    A model for predicting the particle circulation rate in a draft tube spouted bed dryer with inert particles is proposed and verified. The calculation algorithm requires three input values: the gas velocity in the draft tube, one data point for the static pressure in the draft tube, and the pressure gradient in the annulus. The particle circulation rate can be estimated by solving the continuity andmomentum equations for turbulent accelerating two-phase flow. The numerical solution is based on...

  20. 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

    , 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......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...

  1. A study on Heat Transfer for Immersed Tube in Internally Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    TianWendong; HaoJinhua; 等

    1999-01-01

    Heat transfer coefficients for horizontally immersed tubes have been studied in a model of ICFB(Inter-nally Circulating Fluidized Bed).The characteristics in ICFB were found to be significantly different from those in bubbing bed.There is a flowing zone with high velocity in the heat exchange zone.The heat transfer coefficients strongly depend on the fluidized velocity in the flowing zone.The heat exchange process and suitable bed temperature can be controlled according to this feature.Based on the results of the experiments,a formulation for heat transfer has been developed.

  2. Validation of a two-fluid model used for the simulation of dense fluidized beds; Validation d`un modele a deux fluides applique a la simulation des lits fluidises denses

    Energy Technology Data Exchange (ETDEWEB)

    Boelle, A.

    1997-02-17

    A two-fluid model applied to the simulation of gas-solid dense fluidized beds is validated on micro scale and on macro scale. Phase coupling is carried out in the momentum and energy transport equation of both phases. The modeling is built on the kinetic theory of granular media in which the gas action has been taken into account in order to get correct expressions of transport coefficients. A description of hydrodynamic interactions between particles in high Stokes number flow is also incorporated in the model. The micro scale validation uses Lagrangian numerical simulations viewed as numerical experiments. The first validation case refers to a gas particle simple shear flow. It allows to validate the competition between two dissipation mechanisms: drag and particle collisions. The second validation case is concerted with sedimenting particles in high Stokes number flow. It allows to validate our approach of hydrodynamic interactions. This last case had led us to develop an original Lagrangian simulation with a two-way coupling between the fluid and the particles. The macro scale validation uses the results of Eulerian simulations of dense fluidized bed. Bed height, particles circulation and spontaneous created bubbles characteristics are studied and compared to experimental measurement, both looking at physical and numerical parameters. (author) 159 refs.

  3. A small scale regularly packed circulating fluidized bed. Part I: Hydrodynamics.

    NARCIS (Netherlands)

    Ham, van der A.G.J.; Prins, W.; Swaaij, van W.P.M.

    1994-01-01

    The present investigation is based on the idea of intensifying the gas¿solids contact in a circulating fluidized bed by introducing obstacles into it. Such obstacles may effectively suppress radial inhomogeneities in the solids flux and concentration, increase the dynamic solids hold-up, and break u

  4. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-10-30

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period July 1, 2004 through September 30, 2004. The following tasks have been completed. First, renovation of the new Combustion Laboratory and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building have started. Second, the design if the component parts of the CFBC system have been reviewed and finalized so that the drawings may be released to the manufacturers during the next quarter. Third, the experiments for solid waste (chicken litter) incineration have been conducted using a Thermogravimetric Analyzer (TGA). This is in preparation for testing in the simulated fluidized-bed combustor. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter has been outlined in this report.

  6. Coffee parchment in fluidisation

    Directory of Open Access Journals (Sweden)

    Elkin Mauricio López Fontal

    2010-07-01

    Full Text Available All coffee is harvested as cherry grains which are then crushed and extracted traditionally or by applying the Becolsub method. Once the coffee parchment obtained has been washed, it is naturally or mechanically dried. Static dryers are the most used mechanical dryers, generally producing lack of uniformity in the grain’s final humidity content which must range from 10% to 12% b.h. Drying by fluidization was used in the present research work; this turns a solid particle bed into a suspended and expanded mass, possessing many of the properties of a liquid. A 5,000 g capacity prototype was designed and constructed in which coffee was dried at three air drying temperatures: 42°C, 46°C and 49°C; drying time lasted 6 to 8 hours. Good uniformity in final grain humidity content was obtained, differences being less than 0.86%. As well as the grain test, a control cup test was used, finding that the product presented good organoleptic qualities.

  7. Heat Transfer in a Liquid-Solid Circulating Fluidized Bed Reactor with Low Surface Tension Media

    Institute of Scientific and Technical Information of China (English)

    HR Jin; H Lim; DH Lim; Y Kang; Ki-Won Jun

    2013-01-01

    Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of liquid velocity, particle size, surface tension of liquid phase and solid circulation rate on the overall heat transfer coefficient were examined. The heat transfer coefficient increased with increasing particle size or solid cir-culation rate due to the higher potential of particles to contact with the heater surface and promote turbulence near the heater surface. The value of heat transfer coefficient increased gradually with increase in the surface tension of liquid phase, due to the slight increase of solid holdup. The heat transfer coefficient increased with the liquid veloc-ity even in the higher range, due to the solid circulation prevented the decrease in solid holdup, in contrast to that in the conventional liquid-solid fluidized beds. The values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.

  8. Lateral Solids Mixing in the Dense Zone of a Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    YANGHairui; LUEJunfu; 等

    2002-01-01

    Lateral solid mixing was investigated experimentally in the dense zone of a 900mm×100mm×5.2m rectangular circulating fluidized bed riser.Using heated tracer injection,the lateral solid dispersion was determined by measuring the temperature response at different lateral positions. Furthermore, a one-dimensional dispersion model,which describes the solid mixing in the dense zone,is presented.The experimental results were used to determine the lateral particle dispersion coefficient under various operating conditions. A correlation of dispersion coefficient with bed height, gas velocity,and particle size is also proposed.

  9. 3D CFD simulation of hydrodynamics of a 150 MWe circulating fluidized bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    Nan Zhang; Bona Lu; Wei Wang; Jinghai Li [Chinese Academy of Sciences, Beijing (China). Institute of Process Engineering

    2010-08-15

    An Eulerian granular multiphase model with a drag coefficient based on the energy minimization multi-scale (EMMS) model was used to perform a three-dimensional (3D), full-loop, time-dependent simulation of hydrodynamics of a 150 MWe circulating fluidized bed (CFB) boiler. Simulation results were presented in terms of the pressure profile around the whole loop of solids circulation, profiles of solids volume fraction and solids vertical velocity, as well as the non-uniform distribution of solid fluxes into two parallel cyclones.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wei-Ping Pan; Yan Cao; Songgeng Li

    2006-04-01

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2006 through March 31, 2006. Work was performed on the following activities. First, the fabrication and manufacture of the CFBC Facility were completed. The riser, primary cyclone and secondary cyclone of Circulating Fluidized Bed (CFB) Combustor have been erected. Second, the Mercury Control Workshop and the Grand Opening of Institute for Combustion Science and Environmental Technology (ICSET) were successfully held on February 22 and 23, 2006, respectively. Third, effects of hydrogen chlorine (HCl) and sulfur dioxide (SO{sub 2}) on mercury oxidation were studied in a drop tube reactor. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

  11. Development of an Internally Circulating Fluidized Bed Membrane Reactor for Hydrogen Production from Natural Gas

    Institute of Scientific and Technical Information of China (English)

    XIE Dong-lai; GRACE John R; LIM C Jim

    2006-01-01

    An innovative Internally Circulating Fluidized Bed Membrane Reactor (ICFBMR) was designed and operated for ultra-pure hydrogen production from natural gas. The reactor includes internal catalyst solids circulation for conveying heat between a reforming zone and an oxidation zone. In the reforming zone, catalyst particles are transported upwards by reactant gas where steam reforming reactions are taking place and hydrogen is permeating through the membrane surfaces. Air is injected into the oxidation zone to generate heat which is carried by catalyst particles to the reforming zone supporting the endothermic steam reforming reaction. The technology development process is introduced: cold model test,pilot plant and industrial demonstration unit. The process flow diagram and key components of each unit are described.The ICFBMR process has the potential to provide improved performance relative to conventional SMR fixed-bed tubular reactors.

  12. Flow Field of Circulating Fluidized Bed Reactor with Venturi Inlet Configuration

    Institute of Scientific and Technical Information of China (English)

    HU Jinbang; LI Yanping; CHEN Anxin

    2005-01-01

    Different two-equation k-ε models were used to simulate the gas flow field generated by a new type of circulating fluidized bed reactor with venturi gas distributor. The numerical results were compared with the experimental data. It has been shown that the simulation results from the standard k-ε model have the best match with the experimental data. Based on this model, the gas flow field in the venturi diffuser and riser was analyzed by the concept of velocity nonuniformity and dead zone percentage. Both the nonuniformity of gas velocity and the dead zone percentage reach the maximum at the venturi outlet due to the effect of the vortex. At the same time, it provides a good platform for the further optimization of the inlet configuration of circulating fluidized bed reactor.

  13. Chemical Looping Reactor System Design : Double Loop Circulating Fluidized Bed (DLCFB)

    OpenAIRE

    Bischi, Aldo

    2012-01-01

    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 ...

  14. A small scale regularly packed circulating fluidized bed. Part I: Hydrodynamics.

    OpenAIRE

    Ham, van, M.; Prins, W.; Swaaij, van, Wim P.M.

    1994-01-01

    The present investigation is based on the idea of intensifying the gas¿solids contact in a circulating fluidized bed by introducing obstacles into it. Such obstacles may effectively suppress radial inhomogeneities in the solids flux and concentration, increase the dynamic solids hold-up, and break up solids clusters. This article (Part I) deals with the hydrodynamics (pressure drop and solids hold-up) investigated at ambient conditions, for cocurrent upward flow of air and microsize solid par...

  15. Influence of dissolved oxygen in nitrification kinetics in a circulating bed reactor

    OpenAIRE

    V. Lazarova; R. Nogueira; J. Manem; Melo, L. F.

    1997-01-01

    The influence of dissolved oxygen concentration in nitrification kinetics was studied in a new biofilm reactor, the circulating bed reactor (CBR). The study was carried out partly at laboratory scale with synthetic water containing inorganic carbon and nitrogen compounds, and partly at pilot scale for secondary and tertiary nitrification of municipal wastewater. The experimental results showed that, either the ammonia or the oxygen concentration could be limiting for the nitrification rate...

  16. MULTIFRACTAL ANALYSIS OF PARTICLE-FLUID SYSTEM IN A CIRCULATING FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Liping; Ma; Weixing; Huang; Yanfu; Shi; Huarui; Yu; Jingxu; Zhu

    2005-01-01

    In this paper, multifractal analysis together with wavelet transform modulus maxima (WTMM) method is used to analyze the fluctuating signals of circulating fluidized bed (CFB). Singularity spectrum shows that the gas-particle flow in CFB has multifractal character. Motion behavior of the particle-fluid system of CFB can be described by singularity spectrum. Intermittency index can be used to determine the transition of flow regime from fast fluidization to pneumatic conveying.

  17. 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.

  18. Modelling of a circulating fluidized bed using computational fluid dynamic software

    Energy Technology Data Exchange (ETDEWEB)

    Torres, E.C.; Steward, F. [New Brunswick Univ., Centre for Nuclear Research, Fredericton, NB (Canada); Pugsley, T. [New Brunswick Univ., Dept. of Chemical Engineering, Fredericton, NB (Canada)

    1998-09-01

    A computational fluid dynamics (CFD) software called `FLUENT` was used to model the hydrodynamics of the riser of a laboratory scale circulating fluidized bed. A circulating fluidized bed is a type of fluidized bed that operates at high gas velocities. Its two most important applications are for combustion purposes and for fluid catalytic cracking. Results from the simulated cold model were compared with experimental data. Predictions of the model were in good agreement with trends observed experimentally.The two main considerations when applying CFD to the experimental set-up are granular multiphase models and the turbulence conditions for the gas and solid phases. The time dependent model provides outputs that predict the radial and axial distribution of the gas and solids in the riser which correspond to different operating conditions of riser solids mass flux and gas velocity. By introducing more accurate particle flow data at the entrance and at the walls into the boundary conditions the CFD model could be significantly improved.9 refs., 1 tab., 10 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-30

    This purpose of this report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period April 1, 2005 through June 30, 2005. The following tasks have been completed. First, the new Combustion Laboratory was occupied on June 15, 2005, and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building is in the final painting stage. Second, the fabrication and manufacturing contract for the CFBC Facility was awarded to Sterling Boiler & Mechanical, Inc. of Evansville, Indiana. Sterling is manufacturing the assembly and component parts of the CFBC system. The erection of the CFBC system is expected to start September 1, 2005. Third, mercury emissions from the cofiring of coal and chicken waste was studied experimentally in the laboratory-scale simulated fluidized-bed combustion facility. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-04-30

    This report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2005 through March 31, 2005. The following tasks have been completed. First, the renovation of the new Combustion Laboratory is nearly complete, and the construction of the Circulating Fluidized-Bed (CFB) Combustor Building is in the final stages. Second, the fabrication and manufacture of the CFBC Facility is being discussed with a potential contractor. Discussions with potential contactor regarding the availability of materials and current machining capabilities have resulted in the modification of the original designs. The selection of the fabrication contractor for the CFBC Facility is expected during the next quarter. Third, co-firing experiments conducted with coal and chicken waste have been initiated in the laboratory-scale simulated fluidized-bed facility. The experimental results from this study are presented in this report. Finally, the proposed work for the next quarter is described in this report.

  1. Segregation and mixing effects in the riser of a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Mitali Das; Meenakshi Banerjee; R.K. Sah [Indian Institute of Technology, Kharagpur (India). Department of Chemical Engineering

    2007-09-15

    Segregation and mixing effects of binary mixtures of particles having difference in sizes and densities were studied in 0.1016 m-diameter riser of a circulating fluidized bed at gas velocities between 2.01 and 4.681 m/s and solids circulation rate between 12.5 and 50 kg/m{sup 2}s. Two groups of bed materials (three quartz sand-spent fcc catalyst mixtures with different initial mass % of sand and two coal-iron mixtures, one with almost same sizes but with different densities and the other having both different sizes and densities) were used. Using local axial mass % of heavier/coarser particles and their mean sizes the extent of segregation was evaluated. The influence of operating conditions like superficial gas velocity and solids circulation rate on segregation was examined and found that with their increase segregation effects generally tend to decrease and a uniform mixture conforming to initial composition of the mixture results. Using the data available in the literature and those of the present authors an empirical correlation to obtain the extent of segregation in CFBs has been proposed.

  2. The study of solid circulation rate in a compartmented fluidized bed gasifier (CFBG)

    Science.gov (United States)

    Wee, S. K.; Pok, Y. W.; Law, M. C.; Lee, V. C. C.

    2016-06-01

    Biomass waste has been abundantly available in Malaysia since the booming of palm oil industry. In order to tackle this issue, gasification is seen a promising technology to convert waste into energy. In view of the heat requirement for endothermic gasification reaction as well as the complex design and operation of multiple fluidized beds, compartmented fluidized bed gasifier (CFBG) with the combustor and the gasifier as separate compartments is proposed. As such, solid circulation rate (SCR) is one of the essential parameters for steady gasification and combustion to be realized in their respective compartments. Experimental and numerical studies (CFD) on the effect of static bed height, main bed aeration, riser aeration and v-valve aeration on SCR have been conducted in a cold- flow CFBG model with only river sand as the fluidizing medium. At lower operating range, the numerical simulations under-predict the SCR as compared to that of the experimental results. Also, it predicts slightly different trends over the range. On the other hand, at higher operating range, the numerical simulations are able to capture those trends as observed in the experimental results at the lower operating range. Overall, the numerical results compare reasonably well with that of the experimental works.

  3. Circulating fluidized bed combustion ash characterization. The case of the Provence 250 MW unit

    Energy Technology Data Exchange (ETDEWEB)

    Lecuyer, I.; Leduc, M. [Electricite de France (EDF), 78 - Chatou (France). Direction des Etudes et Recherches; Lefevre, R.; Ausset, P. [Paris-12 Univ., Creteil (France). Lab. Interuniversitaire des Systemes Atmospheriques

    1997-05-01

    The Provence 250 MW Circulating Fluidized Bed Combustion Unit (Gardanne, France) is burning a high sulfur (2 to 4%), high ash content (30%) local lignite. This peculiar fuel already contains about 15% of CaO which allows it to capture the sulfur dioxide in situ without adding any complementary sorbent. The ash chemical composition (bed ash and ESP ash) that reflects the particularities of the coal is presented. SEM and DRX observations confirm the presence of anhydrite CaSO{sub 4}, lime, CaS, quartz and traces of hematite. Most of particles are roughly-shaped but microspheres can also be detected in fly ash. The very high sulfate content may be worrying for the environment in disposals. Hardened samples do not seem to retain compounds from leaching: high quantities of calcium and sulfates are still leached from these crushed samples. (author) 10 refs.

  4. Synthesis gas production using oxygen storage materials as oxygen carrier over circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    DAI Xiaoping; YU Changchun; LI Ranjia; WU Qiong; HAO Zhengping

    2008-01-01

    A novel process for synthesis gas production over Circulating Fluidized Bed (CFB) using oxygen storage materials as oxygen carrier was reported. First, oxygen in the air was chemically fixed and converted to lattice oxygen of oxygen storage materials over regenerator, and then methane was selectively oxidized to synthesis gas with lattice oxygen of oxygen storage materials over riser reactor. The results from simulation reaction of CFB by sequential redox reaction on a fixed bed reactor using lanthanum-based perovskite LaFeO3 and La0.8Sr0.2Fe0.9Co0.1O3 oxides prepared by sol-gel, suggested that the depleted oxygen species could be regenerated, and methane could be oxidized to synthesis gas by lattice oxygen with high selectivity. The partial oxidation of methane to synthesis gas over CFB using lattice oxygen of the oxygen storage materials instead of gaseous oxygen should be possibly applicable.

  5. A New Dry Flue Gas Desulfurization Process-Underfeed Circulating Spouted Bed

    Science.gov (United States)

    Tao, M.; Jin, B. S.; Yang, Y. P.

    Applying an underfeed system, the underfeed circulating spouted bed was designed as a desulfurization reactor. The main objective of the technology is to improve the mixing effect and distribution uniformity of solid particles, and therefore to advance the desulfurization efficiency and calcium utility. In this article, a series of experimental studies were conducted to investigate the fluidization behavior of the solid-gas two-phase flow in the riser. The results show that the technology can distinctly improve the distribution of gas velocity and particle flux on sections compared with the facefeed style. Analysis of pressure fluctuation signals indicates that the operation parameters have significant influence on the flow field in the reaction bed. The existence of injecting flow near the underfeed nozzle has an evident effect on strengthening the particle mixing.

  6. Carbon attrition during the circulating fluidized bed combustion of a waste-derived fuel

    Energy Technology Data Exchange (ETDEWEB)

    Arena, U. [Consiglio Nazionale delle Ricerche, Naples (Italy). Inst. for Combustion Research; Naples Univ. (Italy). Dept. of Environmental Sciences; Mastellone, M.L. [Naples Univ. Federico II (Italy). Dept. of Chemical Engineering

    1999-07-01

    A biomass obtained as residue from food manufacturing of pine nuts was batchwise fed in a laboratory scale circulating fluidized bed combustor. The apparatus was operated under both inert and oxidizing conditions in order to establish the relative importance of purely mechanical attrition and combustion-assisted attrition in generating carbon fines. For each run, carbon load and carbon particle size distribution in the riser and rates of attrited carbon fines escaping from the combustor were determined as a function of time. A parallel investigation was carried out with a bubbling fluidized bed combustor in order to point out peculiarities of attrition in the two apparatus. Results were compared with those obtained by burning in the same combustor a bituminous coal and a packaging-derived fuel, obtained from monomaterial collections of polyethylene terephtalate bottles. A different attrition phenomenology was found for each fuel and its peculiar features were taken into account. (orig.)

  7. THREE -PHASE CIRCULATING FLUIDIZED BED EVAPORATOR FOR WHEAT STRAW BLACK LIQUOR EVAPORATION

    Institute of Scientific and Technical Information of China (English)

    Yuan-yuanJia

    2004-01-01

    A novel vapor-liquid-solid circulating fluidized bed evaporator, meaning for enhancing heat transfer and preventing fouling, is applied to wheat straw black liquor, which is the primary pollutant in China's papermaking industry. It is treated by alkali recovery, in which evaporation is a key process. The experimental results show that the vapor-liquid-solid three-phase boiling heat transfer coefficient is enhanced by 20%-40% than that of vapor-liquid two-phase boiling flow, also, the novel evaporator exhibits an excellent function of fouling prevention.

  8. THREE -PHASE CIRCULATING FLUIDIZED BED EVAPORATOR FOR WHEAT STRAW BLACK LIQUOR EVAPORATION

    Institute of Scientific and Technical Information of China (English)

    Yuan-yuan Jia

    2004-01-01

    A novel vapor-liquid-solid circulating fluidized bed evaporator, meaning for enhancing heat transfer and preventing fouling, is applied to wheat straw black liquor, which is the primary pollutant in China′s papermaking industry. It is treated by alkali recovery,in which evaporation is a key process. The experimental results show that the vapor-liquid-solid three-phase boiling heat transfer coefficient is enhanced by 20% ~40% than that of vapor-liquid two-phase boiling flow, also, the novel evaporator exhibits an excellent function of fouling prevention.

  9. 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.

  10. Feasibility of Combustion of Petroleum Coke in 230t/h Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    HAN Dong-tai; SONG Zheng-chang; XU Tao

    2003-01-01

    In order to reuse the high sulfur petroleum coke, the waste in chemical industry, as fuel of power plant for energy recovery, the combustion property of petroleum coke was researched experimentally in circulating fluidized bed (CFB) boiler. The performance of the boiler in burning mixed fuel with different ratios of coal to petroleum coke is obtained. Based on the experimental data, Factors influencing the stability of combustion,thermal efficiency of boiler, and emissions and desulphurisation are discussed. This study demonstrates that the combustion of petroleum coke in CFB boiler is applicable, and has great significance on the design and operation of CFB boiler to burn petroleum coke.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-24

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

  12. Rotational asymmetry of reactant concentration and its evolution in a circulating fluidized bed riser

    Institute of Scientific and Technical Information of China (English)

    Dongbing Li; Ajay K. Ray; Madhumita B. Ray; Jesse Zhu

    2012-01-01

    Rotational asymmetric distribution of reactant (ozone) concentration and its evolution along with the gas-solid reactive flow were studied in a 76 mm i.d.,10.2 m high circulating fluidized bed (CFB) riser reactor.The superficial gas velocity ranged from 3 to 5 m/s and the solids circulation rates were 50 and 100kg/(m2 s).Experimental results show that the asymmetry of reactant distribution can extend to a height close to the length of flow developing zone of the CFB riser reactor and then disappears.Based on the hydrodynamics of the gas and solid phases in the solids entrance region,this asymmetry can be attributed to the effect of the solids entrance structure.

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

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  14. Prediction of the particle circulation rate in a draft tube spouted bed suspension dryer

    Directory of Open Access Journals (Sweden)

    ZORANA LJ. ARSENIJEVIC

    2006-04-01

    Full Text Available A model for predicting the particle circulation rate in a draft tube spouted bed dryer with inert particles is proposed and verified. The calculation algorithm requires three input values: the gas velocity in the draft tube, one data point for the static pressure in the draft tube, and the pressure gradient in the annulus. The particle circulation rate can be estimated by solving the continuity andmomentum equations for turbulent accelerating two-phase flow. The numerical solution is based on an iterative procedure until the assumed value of the particle circulation rate produces the prescribed value of the fluid static pressure at a certain axial position. Experiments were performed in a cylindrical column of 215 mm diameter with a draft tube of 70 mm diameter and length of 900 mm. Polyetylene pellets were used as the inert particles with a diameter of 3.3 mm, a density of 921 kg/m3 and a sphericity of 0.873. The model predictions of the particle circulation rate are in good agreement with the experimental data.

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

    Institute of Scientific and Technical Information of China (English)

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

    2001-01-01

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

  16. 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.

  17. Pilot development of polygeneration process of circulating fluidized bed combustion combined with coal pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Qu, X. [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan (China); Graduate School, Chinese Academy of Sciences, Beijing (China); Liang, P. [College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao (China); Wang, Z. [Ningbo Branch of Academy of Ordnace Science, Ningbo (China); Zhang, R.; Sun, D.; Bi, J. [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan (China); Gong, X. [Hengyuan Coal Electrochemical Co., Ltd, Fugu (China); Gan, Z. [State Key Laboratory of Low Carbon Energy, ENN Science and Technology Ltd, Langfang (China)

    2011-01-15

    A pilot polygeneration process of a 75 t h{sup -1} circulating fluidized bed (CFB) boiler combined with a moving bed coal pyrolyzer was developed based on laboratory-scale experimental results. The process operation showed good consistency and integration between boiler and pyrolyzer. Some critical operating parameters such as hot ash split flow from the CFB boiler to the pyrolyzer, mixing of hot ash and coal particles, control of pyrolysis temperature and solid inventory in the pyrolyzer, and pyrolysis gas clean-up were investigated. Yields of 6.0 wt-% tar and 8.0 wt-% gas with a heating value of about 26 MJ m{sup -3} at 600 C were obtained. Particulate content in tar was restrained less than 4.0 wt-% by using a granular filter of the moving bed. Operation results showed that this pilot polygeneration process was successfully scaled up. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. PIV Visualization of Bubble Induced Flow Circulation in 2-D Rectangular Pool for Ex-Vessel Debris Bed Coolability

    Energy Technology Data Exchange (ETDEWEB)

    Han, Teayang; Kim, Eunho; Park, Hyun Sun; Moriyama, Kiyofumi [POSTECH, Pohang (Korea, Republic of)

    2015-10-15

    The previous research works demonstrated the debris bed formation on the flooded cavity floor in experiments. Even in the cases the core melt is once solidified, the debris bed can be re-melted due to the decay heat. If the debris bed is not cooled enough by the coolant, the re-melted debris bed will react with the concrete base mat. This situation is called the molten core-concrete interaction (MCCI) which threatens the integrity of the containment by generated gases which pressurize the containment. Therefore securing the long term coolability of the debris bed in the cavity is crucial. According to the previous research works, the natural convection driven by the rising bubbles affects the coolability and the formation of the debris bed. Therefore, clarification of the natural convection characteristics in and around the debris bed is important for evaluation of the coolability of the debris bed. In this study, two-phase flow around the debris bed in a 2D slice geometry is visualized by PIV method to obtain the velocity map of the flow. The DAVINCI-PIV was developed to investigate the flow around the debris bed. In order to simulate the boiling phenomena induced by the decay heat of the debris bed, the air was injected separately by the air chamber system which consists of the 14 air-flowmeters. The circulation flow developed by the rising bubbles was visualized by PIV method.

  19. 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.

  20. 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.

  1. Fabrication and properties of foam geopolymer using circulating fluidized bed combustion fly ash

    Institute of Scientific and Technical Information of China (English)

    Ze Liu; Ning-ning Shao; Dong-min Wang; Jun-feng Qin; Tian-yong Huang; Wei Song; Mu-xi Lin; Jin-sha Yuan; Zhen Wang

    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 elec-tron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). The CFA-based foam geopolymer was successfully fabri-cated 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.

  2. 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}.

  3. Strength and thermal behavior of low weight foam geopolymer using circulating fluidized bed combustion fly ash

    Institute of Scientific and Technical Information of China (English)

    刘泽; 邵宁宁; 秦俊峰; 孔凡龙; 王春雪; 王栋民

    2015-01-01

    A comparative study of the influence of elevated temperature on foam geopolymer using circulating fluidized bed combustion fly ash (CFA) was reported. Foam geopoymers were prepared with different amounts of foam agent and different SiO2/Al2O3 molar ratios of 3.1, 3.4, and 3.8. The mechanical, thermo-physical properties and microstructure of the foam geopolymers before and after exposure to elevated temperature of 800, 1000, and 1200 °C were investigated. The specimen with SiO2/Al2O3 molar ratio of 3.8 exhibits the highest compressive strength, better microstructure and dimension stability before and after firing. Carnegeite, nepheline, and zeolite crystalline phases appearing after exposure may contribute to the good post-exposure strength. Low weight foam geopolymer using CFA can increase strength and maintain higher stability as high as 1000 °C.

  4. Heat transfer in a large-scale circulating fluidized bed boiler

    Institute of Scientific and Technical Information of China (English)

    CHENG Leming; WANG Qinhui; SHI Zhenglun; LUO Zhongyang; NI Mingjiang; CEN Kefa

    2007-01-01

    Heat transfer of a furnace in a large-scale circulating fluidized bed (CFB) boiler was studied based on the analysis of available heat transfer coefficient data from typical industrial CFB boilers and measured data from a 12 MWe,a 50 MWe and a 135 MWe CFB boiler.The heat transfer of heat exchanger surfaces in a furnace,in a steam/water cooled cyclone,in an external heat exchanger and in the backpass was also reviewed.Empirical correlation of heat transfer coefficient was suggested after calculating the two key parameters,solids suspension density and furnace temperature.The correlation approach agrees well with the data from the large-scale CFB boilers.

  5. Numerical and experimental study on flue gas desulfurization in the underfeed circulating spouted bed

    Energy Technology Data Exchange (ETDEWEB)

    Tao, M.; Jin, B.S.; Zhong, W.Q.; Yang, Y.P.; Xiao, R. [Southeast University, Nanjing (China). School of Energy & Environment

    2010-05-01

    An underfeed circulating spouted bed (UCSB) reactor was used as a desulfurization apparatus. In this study, an attempt was made to build a mathematical 3D model which couples the complicated flow and chemical reactions in the interest of system analysis and sulfur removal data analysis. A simplified reaction model was developed to describe the SO{sub 2} absorption process. Humidifying, evaporation, neutralization reaction have been considered in the model while the dissolution and ionization of calcium hydroxide are neglected. The effect of operating parameters including feed style, injecting velocity, jet water flow rate, humidifying style on sulfur removal efficiency were investigated. The results show that the calculation gives a good description of the experimental data under the range of operating conditions. It indicates that the model is successful in predicting the desulfurization efficiency of the UCSB system.

  6. Effects of circulating fluidized bed combustion (CFBC) fly ashes as filler on the performances of asphalt

    Energy Technology Data Exchange (ETDEWEB)

    Qin Li; Hui Xu; Xiaoru Fu; Chen Chen; Jianping Zhai [Nanjing University, Nanjing (China). State Key Laboratory of Pollution Control and Resource Reuse

    2009-03-15

    This work investigated the potential of utilizing circulating fluidized bed combustion (CFBC) fly ashes (CFAs) as alternative filler, substituting mineral powders (MPs) that are widely used in asphalt concrete. Physico-chemical characteristics of the CFAs and MPs, as well as effects of different mix designs of CFAs and asphalt on asphalt performances were examined, including moisture susceptibility, viscosity, ductility, softening point, penetration, and antiaging performances. The results of the study show that generally the CFAs have greater effects than the MPs on improving the performances of asphalt, and that the specific surface area (SSA), free CaO (f-CaO), morphology, and mineralogical phases of the CFAs are more favorable than those of the MPs respectively, while the alkaline values, hydrophilic coefficients, particle size distributions (PSDs), and water contents of the two fillers are similar. It is suggested that CFAs may be more suitable than MPs for the use as asphalt concrete filler.

  7. 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)

  8. Co-combustion of agricultural wastes in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Huseyin Topal; Aysel T. Atimtay [Gazi University, Ankara (Turkey). Dept. of Mechanical Engineering

    2005-07-01

    In this study a circulating fluidized bed combustion (CFBC) of 125 mm inside diameter and 1800 mm height was used to investigate the co-combustion characteristics of peach and apricot stones produced as a waste from the fruit juice industry, and sunflower stems produced as a waste from the edible oil industry with a lignite coal. Lignite coal is a coal most widely used in Turkey. On-line concentrations of O{sub 2}, CO, CO{sub 2}, SO{sub 2}, NOx and total hydrocarbons (C{sub m}H{sub n}) were measured in the flue gas during combustion experiments. By changing the operating parameters the variation of emissions of various pollutants were studied. During combustion tests, it was observed that the volatile matter from agro-wastes quickly volatilizes and mostly burn in the riser. The temperature profiles along the bed and the rise also confirmed this phenomenon. It was found that as the volatile matter content of agro-waste increases, the combustion efficiency increases and the combustion takes place more in the upper region of the riser. These results suggest that agro-wastes are potential fuels that can be utilized for clean energy production by using CFBC in countries where agricultural activities are heavy. 3 refs., 4 figs., 5 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-09-30

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wei-Ping Pan; Yan Cao; John Smith

    2007-03-31

    This report is to present the progress made on the project entitled ''Establishment of an Environmental Control Technology Laboratory (ECTL) with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the period January 1, 2007 through March 31, 2007. The effort in this quarter has concentrated on installing the CFBC Facility and for conducting cold fluidization operations tests in the CFBC facility. The assembly of the ash recirculation pipe duct from the cyclones back to the bed area of the combustor, including the upper and lower loop seals was completed. The electric bed pre-heater was installed to heat the fluidizing air as it enters the wind box. The induced draft fan along with its machine base and power supply was received and installed. The flue gas duct from secondary cyclone outlet to induced draft fan inlet was received and installed, as well as the induced fan flue gas discharge duct. Pressure testing from the forced draft fan to the outlet of the induced fan was completed. In related research a pilot-scale halogen addition test was conducted in the empty slipstream reactor (without (Selective Catalytic Reduction) SCR catalyst loading) and the SCR slipstream reactor with two commercial SCR catalysts. The greatest benefits of conducting slipstream tests can be flexible control and isolation of specific factors. This facility is currently used in full-scale utility and will be combined into 0.6MW CFBC in the future. This work attempts to first investigate performance of the SCR catalyst in the flue gas atmosphere when burning Powder River Basin (PRB), including the impact of PRB coal flue gas composition on the reduction of nitrogen oxides (NOx) and the oxidation of elemental mercury (Hg(0)) under SCR conditions. Secondly, the impacts of hydrogen halogens (Hydrogen fluoride (HF), Hydrogen chloride (HCl), Hydrogen Bromide (HBr) and Hydrogen Iodine (HI)) on Hg(0) oxidation and their mechanisms can be explored.

  11. Biological nutrient removal from leachate using a pilot liquid-solid circulating fluidized bed bioreactor (LSCFB).

    Science.gov (United States)

    Eldyasti, Ahmed; Chowdhury, Nabin; Nakhla, George; Zhu, Jesse

    2010-09-15

    Biological treatment of landfill leachate is a concern due to toxicity, high ammonia, low biodegradable organic matter concentrations, and low carbon-to-nitrogen ratio. To study the reliability and commercial viability of leachate treatment using an integrated liquid-solid circulating fluidized bed bioreactor (LSCFB), a pilot-scale LSCFB was established at the Adelaide Pollution Control Plant, London, Ontario, Canada. Anoxic and aerobic columns were used to optimize carbon and nutrient removal capability from leachate using 600 microm lava rock with a total porosity of 61%, at empty bed contact times (EBCTs) of 0.55, 0.49, and 0.41 d. The LSCFB achieved COD, nitrogen, and phosphorus removal efficiencies of 85%, 80%, and 70%, respectively at a low carbon-to-nitrogen ratio of 3:1 and nutrients loading rates of 2.15 kg COD/(m(3) d), 0.70 kg N/(m(3) d), and 0.014 kg P/(m(3) d), as compared with 60-77% COD and 70-79% nitrogen removal efficiencies achieved by upflow anaerobic sludge blanket (UASB) and moving bed bioreactor (MBBR), respectively. The LSCFB effluent characterized by

  12. Experimental Study on Gas—Solid Mass Transfer in Circulating Fluidized Beds.

    Institute of Scientific and Technical Information of China (English)

    WANGLinna; ZHANGLing; 等

    2002-01-01

    This study is devoted to gas-solid mass transfer behavior in heterogeneous two-phase flow. Experiments were carried out in a cold circulating fluidized bed of 3.0m in height and 72mm in diameter with naphthalene particles. Axial and radial distributions of sublimated naphthalene concentration in air were measured with an online concentration monitoring system HP GC-MS. Mass transfer coefficients were obtained under various operating condition, showing that heterogeneous flow structure strongly influences the axial and radial profiles of mass transfer coefficients. In the bottom dense region, mass transfer rate is high due to intensive dynamic behavior and higher relative slip velocity between gas and clusters. In the middle transition region and the upper diluter region, as a result of low mass transfer driving force and the influence of flow structure, mass transfer rate distribution becomes non-uniform. In conclusion, among the operating parameters influencing mass transfer coefficients, the superficial gas velocity is the most important factor and the solid circulation rate should be also taken into account.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nsakala ya Nsakala; Gregory N. Liljedahl

    2003-05-15

    Given that fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this study, ALSTOM Power Inc. (ALSTOM) has investigated several coal fired power plant configurations designed to capture CO{sub 2} from effluent gas streams for use or sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be more economical than in PC or Stoker firing, because recirculated gas flow can be reduced significantly. Oxygen-fired PC and Stoker units require large quantities of recirculated flue gas to maintain acceptable furnace temperatures. Oxygen-fired CFB units, on the other hand, can accomplish this by additional cooling of recirculated solids. The reduced recirculated gas flow with CFB units results in significant Boiler Island cost savings. Additionally, ALSTOM has identified several advanced/novel plant configurations, which improve the efficiency and cost of the CO{sub 2} product cleanup and compression process. These advanced/novel concepts require long development efforts. An economic analysis indicates that the proposed oxygen-firing technology in circulating fluidized boilers could be developed and deployed economically in the near future in enhanced oil recovery (EOR) applications or enhanced gas recovery (EGR), such as coal bed methane recovery. ALSTOM received a Cooperative Agreement from the US

  14. Effect of Air Staging and Limestone Addition on Emissions of SO2 and NOx in Circulating Fluidized Bed Combustion

    International Nuclear Information System (INIS)

    The object of this work is to provide more detailed knowledge about the effect of air staging and its relation to the addition of limestone on the emissions of SO2 and NOx from fluidized bed combustors. This knowledge can be used in models of (circulating) fluidized bed combustors for the development of control strategies. The effect of air staging can be divided in to two parts: (1) The effect on the hydrodynamics in a circulating fluidized bed; and (2) The effect on the local gas concentrations, especially the O2 concentration. In this work the influence of both these effects on the SO2 and NOx emissions from (circulating) fluidized bed combustors with air staging was investigated. In Chapter 2 the influence air staging and the use of secondary air injection on the hydrodynamics in a circulating fluidized beds is described. In the first section of that chapter a literature review is given. In the second section an experimental study is presented on the solids distribution and circulation rate under different air staging conditions. Chapter 3 presents fixed bed studies on the SO2 retention by limestone. To understand the influence of air staging, the effect of oxygen on the SO2 retention was investigated. The kinetics were determined and the so-called grain model was used to model the SO2 retention. In Chapter 4 an extensive study was made on the kinetics of the formation of NO from NH3 and the influence of oxygen on these reactions. The kinetics and the activation energies of both homogenous reactions and reactions catalyzed by limestone were determined and the effect of oxygen was investigated. Chapter 5 presents an experimental study and modeling work on the effect of water and CO2 on the reactivity of limestone. It was found that the presence of water reduced the reactivity of limestone significantly. In Chapter 6 the oxidation of NH3 over partially sulphated limestone is studied. A model is developed that describes the NO formation and selectivity as a

  15. Co-combustion of olive cake with lignite coal in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Aysel T. Atimtay; Huseyin Topal [Middle East Technical University, Ankara (Turkey). Department of Environmental Engineering

    2004-05-01

    In this study, olive cake (OC) was co-fired with coal in a circulating fluidized bed of 125 mm diameter and 1800 mm height. Olive cake is a waste from olive oil production. A lignite coal that is most widely used in Turkey (Tuncbilek lignite) was used together with OC and the combustion characteristics of olive cake (OC)+coal mixture were investigated. The combustion experiments were carried out with various excess air ratios. The excess air ratio, {lambda} has been changed between 1.1 and 2.16. Temperature distribution along the bed was measured with thermocouples. On-line concentrations of O{sub 2}, SO{sub 2}, CO{sub 2}, CO, NOx and total hydrocarbons were measured in the flue gas. Various runs were conducted with each mixture of OC and lignite, namely 25, 50 and 75 wt% OC mixed with lignite. These mixtures were burned with various excess air ratios. Combustion efficiencies of olive cake and lignite coal mixtures are calculated, and the optimum conditions for operating parameters are discussed. There is a sharp decrease observed in the combustion losses due to hydrocarbons and CO as the excess air ratio increases. The minimum emissions are observed at about {lambda} = 1.5. The combustion efficiency for lignite coal changes between 82 and 98% for various excess air ratios used in the study. The results suggest that OC is good fuel that can be mixed with lignite coal for cleaner energy production in small-scale industries by using CFB. Less than 50 wt% OC concentration in the fuel mixture is suggested in order to be within the EU limits for emissions. 11 refs., 12 figs., 7 tabs.

  16. Experimental study of the hydrodynamics and cluster formation in a Circulating Fluidized Bed. Annual report, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, M.; Johnson, E.

    1991-01-01

    A novel non-invasive gas-solid flow measuring technique being developed and tested for studying the hydrodynamics inside the riser of a Circulating Fluidized Bed (CFB). First of the two aims of the overall program, namely, design, development and testing of the technique to characterize the particle and gas velocities in two-phase flows was accomplished in the past year. The ``fringe-model`` laser Doppler anemometry concept has been modified and extended by using particles coated with a fluorescent dye and introducing a narrow band pass filter in the receiving optics. The technique permits optical discrimination between the scattered light (laser wavelength from undyed particles) and the fluorescence emission (longer wavelength). Results from extensive testing of various dye-solvent combinations, counter processor settings, signal-to noise optimization and subsequent flow measurements in the test section have shown that the technique can effectively discriminate between two classes of particles--the smaller seed particles for the gas phase data and the larger bed particles. Use of a two-watt Argon-Ion laser assisted in the non-intrusive probing of the gas-solid flow and in enhancing the signal-to-noise ratio. An uncertainty analysis of LDA measurements is presented. Design of the cold flow CFB model, presently under fabrication, is outlined in this report. The Plexiglas CFB model will be employed for the riser core-annular flow studies using the fluorescence-emission based laser-Doppler anemometry. The results from this study will present a unique detailed description of the complex gas-solid behavior in the CFB riser.

  17. Experimental study of the hydrodynamics and cluster formation in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, M.; Johnson, E.

    1991-01-01

    A novel non-invasive gas-solid flow measuring technique being developed and tested for studying the hydrodynamics inside the riser of a Circulating Fluidized Bed (CFB). First of the two aims of the overall program, namely, design, development and testing of the technique to characterize the particle and gas velocities in two-phase flows was accomplished in the past year. The fringe-model'' laser Doppler anemometry concept has been modified and extended by using particles coated with a fluorescent dye and introducing a narrow band pass filter in the receiving optics. The technique permits optical discrimination between the scattered light (laser wavelength from undyed particles) and the fluorescence emission (longer wavelength). Results from extensive testing of various dye-solvent combinations, counter processor settings, signal-to noise optimization and subsequent flow measurements in the test section have shown that the technique can effectively discriminate between two classes of particles--the smaller seed particles for the gas phase data and the larger bed particles. Use of a two-watt Argon-Ion laser assisted in the non-intrusive probing of the gas-solid flow and in enhancing the signal-to-noise ratio. An uncertainty analysis of LDA measurements is presented. Design of the cold flow CFB model, presently under fabrication, is outlined in this report. The Plexiglas CFB model will be employed for the riser core-annular flow studies using the fluorescence-emission based laser-Doppler anemometry. The results from this study will present a unique detailed description of the complex gas-solid behavior in the CFB riser.

  18. Parametric sensitivity analysis to investigate heptane reforming in circulating fast fluidized bed membrane reactors

    Directory of Open Access Journals (Sweden)

    M.E.E. Abashar

    2015-01-01

    Full Text Available In this paper, we present mathematical modeling and numerical simulation tools in searching the high parameter space of steam reforming of heptane for the key design parameters, which have the potential to give high heptane conversion, high hydrogen yield and hydrogen to carbon monoxide ratio within the industrial limits for the syngas used as a feedstock for the gas to liquid processes (GTL. The system under consideration is the novel circulating fast fluidized bed membrane reactor (CFFBMR. The simulation results show that the hydrogen membrane has a significant role in the displacement of the thermodynamic equilibriums of the reversible reactions and production of ultraclean hydrogen, which can be used as a fuel for the fuel cells. Also the results of the sensitivity analysis show that the best performance of the CFFBMR can be obtained by a proper selection of combination of several parameters of high feed temperatures, high steam to carbon feed ratios, high reaction side pressures coupled with a large permeation area of a composite thin film membrane. These parameters are interacting in a very complex manner to give 100% conversion of heptane and 496.94% increase in hydrogen yield compared to the reformer without hydrogen membrane. It was found that under these selected operating conditions a low H2/CO ratio of 1.15 is achieved satisfying the practical recommended industrial range.

  19. EXPERIMENTAL RESEARCH OF FLOW STRUCTURE IN A GAS-SOLID CIRCULATING FLUIDIZED BED RISER BY PIV

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Particle Imaging Velocimetry (PIV) techniques were applied to investigate the particle motion and cluster properties in a gas-solid two-phase flow in a circulating fluidized bed riser. Visual images and micro-structure of various clusters were captured. After the boundary of clusters was determined by the gray level threshold method, clusters were classified by the distance between particles and the shape and position of clusters. In addition, the process of clusters forming and breaking up was described, and the sizes of clusters were also obtained. With the Minimum Quadric Difference (MQD) cross-correlation algorithm suitable for high-density particles, the axial velocities of the particles were obtained in the dilute phase section. The features of particle motion were revealed by investigating statistically the magnitude and distribution of particle axial velocity in the radial direction. At most radial cross-sections, there exists a parabola-shaped distribution of upward axial velocity of particles, namely, the magnitude of axial velocity in the core region is higher than that near the wall region of the riser.

  20. Synthesis of thermostable geopolymer from circulating fluidized bed combustion (CFBC) bottom ashes.

    Science.gov (United States)

    Xu, Hui; Li, Qin; Shen, Lifeng; Wang, Wei; Zhai, Jianping

    2010-03-15

    Circulating fluidized bed combustion (CFBC) bottom ashes (CBAs) are a class of calcined aluminosilicate wastes with a unique thermal history. While landfill disposal of hazardous element-containing CBAs poses serious challenge, these wastes have long been neglected as source materials for geopolymer production. In this paper, geopolymerization of ground CBAs was investigated. Reactivity of the CBAs was analyzed by respective dissolution of the ashes in 2, 5, and 10N NaOH and KOH solutions. Geopolymer pastes were prepared by activating the CBAs by a series of alkalis hydroxides and/or sodium silicate solutions. Samples were cured at 40 degrees C for 168 h, giving a highest compressive strength of 52.9 MPa. Of the optimal specimen, characterization was conducted by TG-DTA, SEM, XRD, as well as FTIR analyses, and thermal stability was determined in terms of compressive strength evolution via exposure to 800 or 1050 degrees C followed by three cooling regimes, i.e. cooling in air, cooling in the furnace, and immerging in water. The results show that CBAs could serve as favorable source materials for thermostable geopolymers, which hold a promise to replace ordinary Portland cement (OPC) and organic polymers in a variety of applications, especially where fire hazards are of great concern.

  1. Feasibility of manufacturing geopolymer bricks using circulating fluidized bed combustion bottom ash.

    Science.gov (United States)

    Chen, Chen; Li, Qin; Shen, Lifeng; Zhai, Jianping

    2012-06-01

    This paper presents a study on geopolymer bricks manufactured using bottom ash from circulating fluidized bed combustion (CFBC). The alkali activators used for synthesis were sodium silicate, sodium hydroxide, and potassium hydroxide and lithium hydroxide solutions. The study included the impact of alkali activator on compressive strength. The reaction products were analysed by XRD, FT-IR and SEM/EDS. The compressive strength of bricks was dependent on the modulus of the sodium silicate activator and the type and concentration of alkali activator. The highest compressive strength could be gained when the modulus was 1.5, and the value could reach 16.1 MPa (7 d after manufacture) and 21.9 MPa (28 d after manufacture). Under pure alkaline systems, the compressive strength was in the order of 10 M KOH > 10 M NaOH > 5 M LiOH > 5 M KOH > 5 M NaOH. Quartz was the only crystalline phase in the original bottom ash, and no new crystalline phase was found after the reaction. The main product of reaction was amorphous alkali aluminosilicate gel and a small amount of crystalline phase was also found by SEM.

  2. Low-reactive circulating fluidized bed combustion (CFBC) fly ashes as source material for geopolymer synthesis.

    Science.gov (United States)

    Xu, Hui; Li, Qin; Shen, Lifeng; Zhang, Mengqun; Zhai, Jianping

    2010-01-01

    In this contribution, low-reactive circulating fluidized bed combustion (CFBC) fly ashes (CFAs) have firstly been utilized as a source material for geopolymer synthesis. An alkali fusion process was employed to promote the dissolution of Si and Al species from the CFAs, and thus to enhance the reactivity of the ashes. A high-reactive metakaolin (MK) was also used to consume the excess alkali needed for the fusion. Reactivities of the CFAs and MK were examined by a series of dissolution tests in sodium hydroxide solutions. Geopolymer samples were prepared by alkali activation of the source materials using a sodium silicate solution as the activator. The synthesized products were characterized by mechanical testing, scanning electron microscopy (SEM), X-ray diffractography (XRD), as well as Fourier transform infrared spectroscopy (FTIR). The results of this study indicate that, via enhancing the reactivity by alkali fusion and balancing the Na/Al ratio by additional aluminosilicate source, low-reactive CFAs could also be recycled as an alternative source material for geopolymer production.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-15

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

  4. Feasibility of manufacturing geopolymer bricks using circulating fluidized bed combustion bottom ash.

    Science.gov (United States)

    Chen, Chen; Li, Qin; Shen, Lifeng; Zhai, Jianping

    2012-06-01

    This paper presents a study on geopolymer bricks manufactured using bottom ash from circulating fluidized bed combustion (CFBC). The alkali activators used for synthesis were sodium silicate, sodium hydroxide, and potassium hydroxide and lithium hydroxide solutions. The study included the impact of alkali activator on compressive strength. The reaction products were analysed by XRD, FT-IR and SEM/EDS. The compressive strength of bricks was dependent on the modulus of the sodium silicate activator and the type and concentration of alkali activator. The highest compressive strength could be gained when the modulus was 1.5, and the value could reach 16.1 MPa (7 d after manufacture) and 21.9 MPa (28 d after manufacture). Under pure alkaline systems, the compressive strength was in the order of 10 M KOH > 10 M NaOH > 5 M LiOH > 5 M KOH > 5 M NaOH. Quartz was the only crystalline phase in the original bottom ash, and no new crystalline phase was found after the reaction. The main product of reaction was amorphous alkali aluminosilicate gel and a small amount of crystalline phase was also found by SEM. PMID:22856304

  5. Study on the flow in the pipelines of the support system of circulating fluidized bed

    Science.gov (United States)

    Meng, L.; Yang, J.; Zhou, L. J.; Wang, Z. W.; Zhuang, X. H.

    2013-12-01

    In the support system of Circulating Fluidized Bed (Below referred to as CFB) of thermal power plant, the pipelines of primary wind are used for transporting the cold air to the boiler, which is important in controlling and combustion effect. The pipeline design will greatly affect the energy loss of the system, and accordingly affect the thermal power plant economic benefits and production environment. Three-dimensional numerical simulation is carried out for the pipeline internal flow field of a thermal power plant in this paper. Firstly three turbulence models were compared and the results showed that the SST k-ω model converged better and the energy losses predicted were closer to the experimental results. The influence of the pipeline design form on the flow characteristics are analysed, then the optimization designs of the pipeline are proposed according to the energy loss distribution of the flow field, in order to reduce energy loss and improve the efficiency of tunnel. The optimization plan turned out to be efficacious; about 36% of the pressure loss is reduced.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-04-01

    The purpose of this report is to present the progress made on the project ''Establishment of an Environmental Control Technology Laboratory with a Circulating Fluidized-Bed Combustion (CFBC) System'' during the quarter January--March 2004. The following tasks have been completed. First, plans for the renovation of space for a new Combustion Laboratory for the CFBC Facility have progressed smoothly. Second, the design calculations, including the mass balances, energy balances, heat transfer, and strength calculations have been completed. Third, considerable modifications have been made on the draft design of the CFBC Facility based on discussions conducted during the project kick-off meeting held on January 13, 2004 at the National Energy Technology Laboratory (NETL). Comments received from various experts were also used to improve the design. Finally, the drawings of all assembly parts have been completed in order to develop specifications for the fabrication of individual parts. At the same time, the proposed work for the next quarter has been outlined in this report.

  7. An Experimental and Computational Study of Multiphase Flow Behaviour in Circulating Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

    Mathiesen, Vidar

    1997-12-31

    Gas/solid flows have been studied extensively, mainly because they are important in nuclear, chemical and petroleum industries. This thesis describes an experiment done at two different circulating fluidized bed systems. Laser Doppler anemometry (LDA) and phase Doppler anemometry (PDA) were used to measure mean and fluctuating velocity, diameter and solids concentration. A typical core-annulus flow was obtained in both cases. The measurements show a relative mean velocity as well as a relative fluctuating velocity between different particle sizes. An axial segregation by size and its variation with the superficial gas velocity are demonstrated. Significant radial segregation is found in both risers. A three-dimensional Computational Fluid Dynamics model was developed based on Eulerian description of the phases where the kinetic theory of granular flow is the basis of the turbulence modelling in the solid phases. There are one gas phase and any number of solid phases. Simulations of flow behaviour in two- and three-dimensions agree well with experiments and the model is able to handle axial segregation by size for different superficial gas velocities and particle size distributions. 107 refs., 79 figs., 6 tabs.

  8. CFD simulation of smooth and T-abrupt exits in circulating fluidized bed risers

    Institute of Scientific and Technical Information of China (English)

    Xuezhi Wu; Fan Jiang; Xiang Xu; Yunhan Xiao

    2010-01-01

    Gas-solid flow in circulating fluidized bed(CFB)risers depends not only on operating conditions but also on exit configurations.Few studies investigated the effects of exit configurations on flow structure using computational fluid dynamics(CFD).This paper provides a 2D two-fluid model to simulate a cold bench-scale square cross-section riser with smooth and T-abrupt exits.The drag force between the gas and solid phases plays an important role in CFD.Since the drag force model based on homogeneous twophase flow,such as the Wen-Yu correlation,could not capture the heterogeneous structures in gas-solid flow,the structure-dependent energy-minimization multi-scale(EMMS)drag force model(Wang.Ge,&Li,2008),applicable for Geldart B particles(sand),was integrated into the two-fluid model.The calculated axial solids hold-up profiles were respectively exponential curve for smooth exit and C-shaped curve for T-abrupt exit,both consistent with experimental data.This study once again proves the key role of drag force in CFD simulation and also shows the validity of CFD simulation(two-fluid model)to describe exit effects on gas-solid flow in CFB risers.

  9. Diagnostics And Treatment Of Patients With Blood Circulation Insufficiency In Vertebrobasilar Bed

    Directory of Open Access Journals (Sweden)

    A.M. Khachatryan

    2009-12-01

    Full Text Available For improvement of treatment results of patients with vertebrobasilar insufficiency we have analyzed data of medical examination and treatment of 182 patients stayed in clinics of Hospital Surgery and Nervous System Diseases from the 1st of January of 2005 till the 30th of June of 2009. Method of screening diagnostics, quantitative and qualitative blood flow estimation by means of Doppler ultrasonic investigation and angiography have been performed. The cause of blood circulation insufficiency in the vertebrobasilar bed at 87 patients was vertebral artery syndrome and in 95 cases there were the significant hemodynamical damages of blood flow in aorta arch branches and intracranial arteries. The neuroangiotropic therapy has been made for all patients, but the clinical improvement period was short in most cases, more prolonged effect was observed in addition of conservative therapy with plasmapheresis by indications. In the complex treatment of patients with vertebrobasilar insufficiency accompanied by degenerative diseases of spine chemical sympathectomy of vertebral artery in the III segment in the form of procaine and spirit-procaine blockades was made in 116 and 69 cases accordingly. The surgical sympathectomy was made in 15 patients. The surgical operations were made in 62 of 95 patients with significant hemodynamic pathology of blood flow in the vertebrobasilar region. In most cases isolative and combinative reconstructive surgery on carotid arteries was carried out. It played a significant role in blood flow correction. Favorable postoperative results were observed in most cases (93, 5%

  10. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Directory of Open Access Journals (Sweden)

    Balicki Adrian

    2014-06-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of ‘zeroemission’ technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  11. Design of Complex Systems to Achieve Passive Safety: Natural Circulation Cooling of Liquid Salt Pebble Bed Reactors

    Science.gov (United States)

    Scarlat, Raluca Olga

    This dissertation treats system design, modeling of transient system response, and characterization of individual phenomena and demonstrates a framework for integration of these three activities early in the design process of a complex engineered system. A system analysis framework for prioritization of experiments, modeling, and development of detailed design is proposed. Two fundamental topics in thermal-hydraulics are discussed, which illustrate the integration of modeling and experimentation with nuclear reactor design and safety analysis: thermal-hydraulic modeling of heat generating pebble bed cores, and scaled experiments for natural circulation heat removal with Boussinesq liquids. The case studies used in this dissertation are derived from the design and safety analysis of a pebble bed fluoride salt cooled high temperature nuclear reactor (PB-FHR), currently under development in the United States at the university and national laboratories level. In the context of the phenomena identification and ranking table (PIRT) methodology, new tools and approaches are proposed and demonstrated here, which are specifically relevant to technology in the early stages of development, and to analysis of passive safety features. A system decomposition approach is proposed. Definition of system functional requirements complements identification and compilation of the current knowledge base for the behavior of the system. Two new graphical tools are developed for ranking of phenomena importance: a phenomena ranking map, and a phenomena identification and ranking matrix (PIRM). The functional requirements established through this methodology were used for the design and optimization of the reactor core, and for the transient analysis and design of the passive natural circulation driven decay heat removal system for the PB-FHR. A numerical modeling approach for heat-generating porous media, with multi-dimensional fluid flow is presented. The application of this modeling

  12. Numerical Modeling of Reactive Multiphase Flow for FCC and Hot Gas Desulfurization Circulating Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-07-01

    This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidized bed and in the process indentifying the parameters that affect the performance of the sulfidation reactor. Two different gas-solid reaction models, the unreacted shrinking core (USC) and the grain model were applied to take into account chemical reaction resistances. Also two different approaches were used to affect the hydrodynamics of the process streams. The first model takes into account the effect of micro-scale particle clustering by adjusting the gas-particle drag law and the second one assumes a turbulent core with pseudo-steady state boundary condition at the wall. A comparison is made with experimental results.

  13. Radiative heat transfer in strongly forward scattering media of circulating fluidized bed combustors

    Science.gov (United States)

    Ates, Cihan; Ozen, Guzide; Selçuk, Nevin; Kulah, Gorkem

    2016-10-01

    Investigation of the effect of particle scattering on radiative incident heat fluxes and source terms is carried out in the dilute zone of the lignite-fired 150 kWt Middle East Technical University Circulating Fluidized Bed Combustor (METU CFBC) test rig. The dilute zone is treated as an axisymmetric cylindrical enclosure containing grey/non-grey, absorbing, emitting gas with absorbing, emitting non/isotropically/anisotropically scattering particles surrounded by grey diffuse walls. A two-dimensional axisymmetric radiation model based on Method of Lines (MOL) solution of Discrete Ordinates Method (DOM) coupled with Grey Gas (GG)/Spectral Line-Based Weighted Sum of Grey Gases Model (SLW) and Mie theory/geometric optics approximation (GOA) is extended for incorporation of anisotropic scattering by using normalized Henyey-Greenstein (HG)/transport approximation for the phase function. Input data for the radiation model is obtained from predictions of a comprehensive model previously developed and benchmarked against measurements on the same CFBC burning low calorific value indigenous lignite with high volatile matter/fixed carbon (VM/FC) ratio in its own ash. Predictive accuracy and computational efficiency of nonscattering, isotropic scattering and forward scattering with transport approximation are tested by comparing their predictions with those of forward scattering with HG. GG and GOA based on reflectivity with angular dependency are found to be accurate and CPU efficient. Comparisons reveal that isotropic assumption leads to under-prediction of both incident heat fluxes and source terms for which discrepancy is much larger. On the other hand, predictions obtained by neglecting scattering were found to be in favorable agreement with those of forward scattering at significantly less CPU time. Transport approximation is as accurate and CPU efficient as HG. These findings indicate that negligence of scattering is a more practical choice in solution of the radiative

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhen Fan

    2006-05-30

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

  15. Bottom ash from fluidising bed boilers as filler material in district heating pipe culverts. Chemical and geotechnical characterisation; Pannsand som kringfyllnadsmaterial foer fjaerrvaermeroergravar. Kemisk och geoteknisk karaktaerisering av fluidbaeddsand

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Roger; Rogbeck, Jan; Suer, Pascal

    2004-01-01

    Bottom ashes from fluid bed boilers have been characterised, both geotechnically and chemically, in order to investigate the possibility to use them as filler material in district heating pipe culverts. Bottom ashes from both biofuel boilers and waste boilers are represented in this project. The companies which ashes have been characterised are Sundsvall Energi AB, Sydkraft OestVaerme AB, Sydkraft MaelarVaerme AB, Eskilstuna Miljoe och Energi, Stora Enso Fors, Soederenergi and Fortum Vaerme. A total of ten ashes have been analysed where three ashes originates from Sundsvall Energi AB, two from Sydkraft OestVaerme AB and one from the each of the remaining companies. The chemical analyses have been performed both on fresh ashes and on ashes aged for three months. The geotechnical analyses performed are grain size distribution, packing abilities and permeability. Chemical analyses performed are total content, available content, leaching tests (leaching both by shaking method and column procedure) and organic analyses (PAH, EOX, TOC, dioxin and fenol). The geotechnical analyses show that the ashes fulfils the demands that are put on the filler material used in district heating pipe culverts. When using the ashes in applications, light compaction should be performed due to the risk of crushing the material which may cause an increased amount of fine material. The leachability of fine material is larger than for coarse material. The ashes are relatively insensitive to precipitation. Bio fuel based bottom ashes have a lower content of environmental affecting substances than waste fuel based ashes. This is also shown in the leaching analyses. The leaching water from fresh ashes contains a higher concentration of leachable components than aged ashes. When aged the pH in the ashes decreases due to carbon uptake and hydration and this makes metals as Pb, Cu, Cr and Zn less mobile. On the other hand, an increase in leachability of Sb, Mo and SO{sub 4} is shown when the ashes

  16. An Experimental Study of Liquid-Solid Flow in a Circulating Fluidized Bed of Varying Liquid Viscosity

    Directory of Open Access Journals (Sweden)

    nirmala sundaram

    2015-01-01

    Full Text Available Hydrodynamics plays a major role in the design of an industrial liquid-solid circulating fluidized bed (LSCFB system. Till date, research investigations have been carried out with tap water as a liquid phase in an LSCFB. But still there is a limited understanding regarding the circulation of particles in an LSCFB with viscous fluids. The aim of our study was to characterize the hydrodynamics in an LSCFB with varying viscosity. Experiments were conducted in a fluidized bed riser of 0.1 m diameter by 2.4 m height with different viscous liquids to study the effects of the operating parameters, namely, primary velocity, secondary velocity, and total velocity, on the hydrodynamic characteristics of the LSCFB with reference to its solid holdup, solid circulation rate, and particle velocity. Experiments were conducted using water and glycerol at different concentrations, and the solid particles (sand and resin of different densities, but same diameter were used in the experiment. The results indicate that the solid holdup in the riser was axially uniform for viscous liquids, which increased with an increase in auxiliary velocity. The average solid holdup decreased with an increase in total velocity, and it increased with an increase in liquid viscosity as the critical transitional velocity decreased with an increase in viscosity. The solid circulation rate was found to be increased with increased total velocity, auxiliary velocity, and viscosity.

  17. Desulphurization in peat-fired circulating and bubbling fluidized bed boilers

    Energy Technology Data Exchange (ETDEWEB)

    Kouvo, P. [Imatran Voima Oy, Vantaa (Finland); Salmenoja, K. [Kvaerner Pulping Oy, Tampere (Finland)

    1997-12-31

    The new emission limit values for large combustion plants are under consideration both at the EU level and in Finland. Peat and wood are the only indigenous fuels of Finland. In 1995 appr. 8 % of electricity was produced with peat. The lower heating value of peat is around 10 MJ/kg. The moisture content varies between 35-55 % and sulphur content in dry solids between 0.15-0.35 %. The total peat power capacity of Finland in 1995 was 1400 MW. Because there was not enough information available about the desulphurization of the flue gases from peat-fired fluidized bed boilers, a group of Finnish companies and Ministry of Trade and Industry decided to carry out the full-scale desulphurisation study. In the project the desulphurization with limestone injection into the furnace of two types of peat-fired boilers were studied. The goal of the project was to investigate: what the technically and economically feasible emission level is by limestone injection in the fluidized bed combustion; how the limestone injection affects the other flue gas emissions and the fouling of the boiler and, what the economy of desulphurisation is. The tests were carried out at Kokkola and Kemi power plants in Finland. At Kokkola (108 MW{sub f}) circulating fluidized bed boiler, the emission limit of 200 mg/m{sup 3}n was leached at a Ca/S-molar ratio of appr. 10, with limestone containing 92 % of calcium carbonate, CaCO{sub 3}. At Kemi (267 MW{sub f}) bubbling fluidized bed boiler, the emission limit of 280 mg/m{sup 3}n with limestone containing appr. 95 % of CaCO{sub 3} was reached at a Ca/S-molar ratio of appr. 7.0. Emissions of NO{sub x}, N{sub 2}O, NH{sub 3} and dust after the ESP were not elevated due to the limestone feed. At the Kokkola power plant the NO{sub x} emissions varied from 300 to 400 mg/m{sup 3}n, and, at the Kemi power station the NO{sub x} emissions were around 200 mg/m{sup 3}n. The fouling of the Kemi boiler was found to be significant in the scheduled outage after the test

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

    Energy Technology Data Exchange (ETDEWEB)

    Wei-Ping Pan; Yan Cao; John Smith

    2008-05-31

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

  19. Experimental study on the reuse of spent rapidly hydrated sorbent for circulating fluidized bed flue gas desulfurization.

    Science.gov (United States)

    Li, Yuan; Zheng, Kai; You, Changfu

    2011-11-01

    Rapidly hydrated sorbent, prepared by rapidly hydrating adhesive carrier particles and lime, is a highly effective sorbent for moderate temperature circulating fluidized bed flue gas desulfurization (CFB-FGD) process. The residence time of fine calcium-containing particles in CFB reactors increases by adhering on the surface of larger adhesive carrier particles, which contributes to higher sorbent calcium conversion ratio. The circulation ash of CFB boilers (α-adhesive carrier particles) and the spent sorbent (β and γ-adhesive carrier particles) were used as adhesive carrier particles for producing the rapidly hydrated sorbent. Particle physical characteristic analysis, abrasion characteristics in fluidized bed and desulfurization characteristics in TGA and CFB-FGD systems were investigated for various types of rapidly hydrated sorbent (α, β, and γ-sorbent). The adhesion ability of γ-sorbent was 50.1% higher than that of α-sorbent. The abrasion ratio of β and γ-sorbent was 16.7% lower than that of α-sorbent. The desulfurization abilities of the three sorbent in TGA were almost same. The desulfurization efficiency in the CFB-FGD system was up to 95% at the bed temperature of 750 °C for the β-sorbent. PMID:21928832

  20. Encapsulated multicellular spheroids of rat hepatocytes produce albumin and urea in a spouted bed circulating culture system.

    Science.gov (United States)

    Takabatake, H; Koide, N; Tsuji, T

    1991-12-01

    Multicellular spheroids are spherical cell-aggregates that retain tridimensional architecture and tissue-specific functions. For use of multicellular spheroids of hepatocytes in a bioreactor for hybrid artificial liver support, we studied the effect of encapsulation and circulating culture on their integrity and tissue-specific functions. Multicellular spheroids of rat hepatocytes were encapsulated into microdroplets of calcium alginate gel and were used as a bioreactor in medium circulating in a spouted bed chamber. Approximately 10% of the hepatocytes of an adult rat were entrapped in a bioreactor chamber, connected to a gas exchanger and a medium reservoir. The total bed volume of the system was 250 ml. The pH and DO2 of the hormonally defined circulating medium was maintained constantly. Albumin and urea were produced in a linear fashion for 64 h at the rates of 0.02 micrograms/microgram cell protein/day and 0.15-0.2 ng/micrograms cell protein/day, respectively. Viability and structural stability of the spheroids were well preserved after the culture period. These results indicate that these encapsulated multicellular hepatocyte spheroids will provide a useful bioreactor for the continuous production of albumin, in vitro and also a prototype hybrid artificial liver support. PMID:1763969

  1. Design of Complex Systems to Achieve Passive Safety: Natural Circulation Cooling of Liquid Salt Pebble Bed Reactors

    Science.gov (United States)

    Scarlat, Raluca Olga

    This dissertation treats system design, modeling of transient system response, and characterization of individual phenomena and demonstrates a framework for integration of these three activities early in the design process of a complex engineered system. A system analysis framework for prioritization of experiments, modeling, and development of detailed design is proposed. Two fundamental topics in thermal-hydraulics are discussed, which illustrate the integration of modeling and experimentation with nuclear reactor design and safety analysis: thermal-hydraulic modeling of heat generating pebble bed cores, and scaled experiments for natural circulation heat removal with Boussinesq liquids. The case studies used in this dissertation are derived from the design and safety analysis of a pebble bed fluoride salt cooled high temperature nuclear reactor (PB-FHR), currently under development in the United States at the university and national laboratories level. In the context of the phenomena identification and ranking table (PIRT) methodology, new tools and approaches are proposed and demonstrated here, which are specifically relevant to technology in the early stages of development, and to analysis of passive safety features. A system decomposition approach is proposed. Definition of system functional requirements complements identification and compilation of the current knowledge base for the behavior of the system. Two new graphical tools are developed for ranking of phenomena importance: a phenomena ranking map, and a phenomena identification and ranking matrix (PIRM). The functional requirements established through this methodology were used for the design and optimization of the reactor core, and for the transient analysis and design of the passive natural circulation driven decay heat removal system for the PB-FHR. A numerical modeling approach for heat-generating porous media, with multi-dimensional fluid flow is presented. The application of this modeling

  2. 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...... quartz reactor was measured. It was found that calcined Stevns Chalk is a very active catalyst for N2O decomposition in an inert atmosphere compared to bed material, i.e. a mixture of ash and sand. However, in FBC the limestone is exposed to a mixture of gases, including CO, CO2 and SO2, and sulphation...

  3. Recycling of composite materials using fluidised bed processes

    OpenAIRE

    Fenwick, Neal

    1996-01-01

    Lightweight engineering plastics have been increasingly used in automotive applications(3), this tends toward more fuel efficient vehicles(1). Glass reinforced plastics commonly include thermosetting polymers. These cannot be re-moulded, unlike thermoplastics, thus thermoset scrap is currently disposed of in landfill. This is increasingly targeted by legislation(14) and is becoming more expensive. This thesis describes work to maximise resource recovery from scrap thermoset composites. A...

  4. Chemical Processes Related to Combustion in Fluidised Bed

    Energy Technology Data Exchange (ETDEWEB)

    Steenari, Britt-Marie; Lindqvist, Oliver [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Environmental Inorganic Chemistry

    2002-12-01

    This report covers work that has been carried out in the combustion chemistry group at the Dept. of Environmental Inorganic Chemistry, Chalmers, within the STEM project 12859-1, during the period 2000-07-01 to 2002-06-30. The work was comprised of the following parts: Sulphur chemistry under pressurised and atmospheric conditions; Gas/solid reactions related to sintering and fouling; Chemistry of volatile metals in combustion; Ash leaching properties; Theoretical modelling of the interactions between ions in a solution and mineral surfaces; Some related issues and co-operations with other departments. The work on sulphur chemistry has been a central issue in our group and it has now been finalised with a PhD thesis discussing some aspects of the sulphation of limestone under pressurised conditions. The influence of a number of parameters on the sulphation efficiency was investigated and compared with similar studies under atmospheric conditions. In a special study it was shown that the influence of alternating calcining - non-calcining conditions on the conversion was substantial. In addition, the oxidation of CaS and sulphided limestone was studied and a regeneration method for the sulphide sorbent was proposed. In the project part concerning gas - solid reactions that are relevant to sintering and fouling, the application of an on-line measurement technique for the study of alkali metal capture by kaolin or other sorbents is described. A new reactor set-up has been constructed and the initial results from this set up are promising. The chemistry of cadmium in combustion of MSW and biomass is the object of a PhD project. This work has been concentrated on the task of identifying Cd-compounds in fly ash samples. It has now come to a point where enough data has been collected to make it possible to give an indication about the Cd speciation in some ash types. In MSW ash particles, cadmium seem to occur mainly as chloride, oxide and sulphate. The work will continue with evaluation of other biomass ash particles and, as an extension, the speciation of Cu and Zn will be studied as well. Ash fractions from combustion of MSW in a BFB boiler have been investigated regarding composition and leaching properties, i.e. environmental impact risks. The release of salts from the cyclone ash fraction can be minimised by the application of a simple washing process, thus securing that the leaching of soluble substances stays within the regulative limits. The MSW ash - water systems contain some interesting chemical issues, such as the interactions between Cr(VI) and reducing substances like Al-metal. The understanding of such chemical processes is important since it gives a possibility to predict effects of a change in ash composition. An even more detailed understanding of interactions between a solution containing ions and particle surfaces can be gained by theoretical modelling. In this project (and with additional unding from Aangpannefoereningens Forskningsstiftelse) a theoretical description of ion-ion interactions and the solid-liquid-interface has been developed. Some related issues are also included in this report. The publication of a paper on the reactions of ammonia in the presence of a calcining limestone surface is one of them. A review paper on the influence of combustion conditions on the properties of fly ash and its applicability as a cement replacement in concrete is another. The licentiate thesis describing the sampling and measurement of Cd in flue gas is also included since it was finalised during the present period. A co-operation project involving the Geology Dept. at Goeteborg Univ. and our group is briefly discussed. This project concerns the utilisation of granules produced from wood ash and dolomite as nutrient source for forest soil. Finally, the plans for our flue gas simulator facility are discussed.

  5. Development of Methane and Nitrous Oxide Emission Factors for the Biomass Fired Circulating Fluidized Bed Combustion Power Plant

    OpenAIRE

    Chang-Sang Cho; Jae-Hwan Sa; Ki-Kyo Lim; Tae-Mi Youk; Seung-Jin Kim; Seul-Ki Lee; Eui-Chan Jeon

    2012-01-01

    This study makes use of this distinction to analyze the exhaust gas concentration and fuel of the circulating fluidized bed (CFB) boiler that mainly uses wood biomass, and to develop the emission factors of Methane (CH4), Nitrous oxide (N2O). The fuels used as energy sources in the subject working sites are Wood Chip Fuel (WCF), RDF and Refused Plastic Fuel (RPF) of which heating values are 11.9 TJ/Gg, 17.1 TJ/Gg, and 31.2 TJ/Gg, respectively. The average concentrations of CH4 and N2O were me...

  6. Innovative Method Using Magnetic Particle Tracking to Measure Solids Circulation in a Spouted Bed

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Ms. Emily [Waynesburg University; Halow, John [Waynesburg University; Daw, C Stuart [ORNL

    2010-01-01

    We describe an innovative method for measuring particle motion inside spouted fluidized beds. The method uses a magnetic tracer particle, which follows the bulk particle flow and is continuously tracked by multiple magnetic field detectors located outside the bed. We analyze signals from the detectors to determine the tracer position at each instant in time. From statistical analysis of the tracer trajectory, characteristic measures of the bulk particle flow, such as the average recirculation frequency, can be determined as a function of operating conditions. For experiments with a range of particle sizes and densities in a 3.9-cm-diameter spouted bed, we find that average solids recirculation rates correlate with excess velocity (superficial minus minimum spouting velocity), particle density, and bed depth.

  7. Innovative method using magnetic particle tracking to measure solids circulation in a spouted fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Ms. Emily [Waynesburg University; Halow, John [Waynesburg University; Daw, C Stuart [ORNL

    2009-01-01

    We describe an innovative method for measuring particle motion inside spouted fluidized beds. The method uses a magnetic tracer particle, which follows the bulk particle flow and is continuously tracked by multiple magnetic field detectors located outside the bed. We analyze signals from the detectors to determine the tracer position at each instant in time. From statistical analysis of the tracer trajectory, characteristic measures of the bulk particle flow, such as the average recirculation frequency, can be determined as a function of operating conditions. For experiments with a range of particle sizes and densities in a 3.9-cm-diameter spouted bed, we find that average solids recirculation rates correlate with excess velocity (superficial minus minimum spouting velocity), particle density, and bed depth.

  8. Investigation on Horizontal Mixing of Particles in Dense Bed in Circulating Fluidized Bed(CFB)

    Institute of Scientific and Technical Information of China (English)

    XiaoPing; YanGuizhang; 等

    1998-01-01

    A two dimensional cold CFB test rig has been established.investigation on horizontal mixing of particles in dense bed has been caried out on this test rig.Miaing model has been used in data reduction,the horizontal mixing coefficients of particles in different experimental conditions and in different structures of dense bed have been obtained and compared.By using dimensional analysis,non-dimensional expression of experimental condition and mixing coefficient have been obtained.

  9. Final Environmental Impact Statement for the JEA Circulating Fluidized Bed Combustor Project

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    2000-06-30

    This EIS assesses environmental issues associated with constructing and demonstrating a project that would be cost-shared by DOE and JEA (formerly the Jacksonville Electric Authority) under the Clean Coal Technology Program. The project would demonstrate circulating fluidized bed (CFB) combustion technology at JEA's existing Northside Generating Station in Jacksonville, Florida, about 9 miles northeast of the downtown area of Jacksonville. The new CFB combustor would use coal and petroleum coke to generate nearly 300 MW of electricity by repowering the existing Unit 2 steam turbine, a 297.5-MW unit that has been out of service since 1983. The proposed project is expected to demonstrate emission levels of sulfur dioxide (SO{sub 2}), oxides of nitrogen (NO{sub x}), and particulate matter that would be lower than Clean Air Act limits while at the same time producing power more efficiently and at less cost than conventional coal utilization technologies. At their own risk, JEA has begun initial construction activities without DOE funding. Construction would take approximately two years and, consistent with the original JEA schedule, would be completed in December 2001. Demonstration of the proposed project would be conducted during a 2-year period from March 2002 until March 2004. In addition, JEA plans to repower the currently operating Unit 1 steam turbine about 6 to 12 months after the Unit 2 repowering without cost-shared funding from DOE. Although the proposed project consists of only the Unit 2 repowering, this EIS analyzes the Unit 1 repowering as a related action. The EIS also considers three reasonably foreseeable scenarios that could result from the no-action alternative in which DOE would not provide cost-shared funding for the proposed project. The proposed action, in which DOE would provide cost-shared finding for the proposed project, is DOE's preferred alternative. The EIS evaluates the principal environmental issues, including air quality

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-10-01

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

  11. Final Environmental Impact Statement for the JEA Circulating Fluidized Bed Combustor Project

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    2000-06-30

    This EIS assesses environmental issues associated with constructing and demonstrating a project that would be cost-shared by DOE and JEA (formerly the Jacksonville Electric Authority) under the Clean Coal Technology Program. The project would demonstrate circulating fluidized bed (CFB) combustion technology at JEA's existing Northside Generating Station in Jacksonville, Florida, about 9 miles northeast of the downtown area of Jacksonville. The new CFB combustor would use coal and petroleum coke to generate nearly 300 MW of electricity by repowering the existing Unit 2 steam turbine, a 297.5-MW unit that has been out of service since 1983. The proposed project is expected to demonstrate emission levels of sulfur dioxide (SO{sub 2}), oxides of nitrogen (NO{sub x}), and particulate matter that would be lower than Clean Air Act limits while at the same time producing power more efficiently and at less cost than conventional coal utilization technologies. At their own risk, JEA has begun initial construction activities without DOE funding. Construction would take approximately two years and, consistent with the original JEA schedule, would be completed in December 2001. Demonstration of the proposed project would be conducted during a 2-year period from March 2002 until March 2004. In addition, JEA plans to repower the currently operating Unit 1 steam turbine about 6 to 12 months after the Unit 2 repowering without cost-shared funding from DOE. Although the proposed project consists of only the Unit 2 repowering, this EIS analyzes the Unit 1 repowering as a related action. The EIS also considers three reasonably foreseeable scenarios that could result from the no-action alternative in which DOE would not provide cost-shared funding for the proposed project. The proposed action, in which DOE would provide cost-shared finding for the proposed project, is DOE's preferred alternative. The EIS evaluates the principal environmental issues, including air quality

  12. Draft Environmental Impact Statement for the JEA Circulating Fluidized Bed Combustor Project

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    1999-08-27

    This EIS assesses environmental issues associated with constructing and demonstrating a project that would be cost-shared by DOE and JEA (formerly the Jacksonville Electric Authority) under the Clean Coal Technology Program. The project would demonstrate circulating fluidized bed (CFB) combustion technology at JEA's existing Northside Generating Station in Jacksonville, Florida, which occupies a 400-acre industrial site along the north shore of the St. Johns River about 9 miles northeast of the downtown area of Jacksonville. The new CFB combustor would use coal and petroleum coke to generate nearly 300 MW of electricity by repowering the existing Unit 2 steam turbine, a 297.5-MW unit that has been out of service since 1983. The proposed project is expected to demonstrate emission levels of sulfur dioxide (SO{sub 2}), oxides of nitrogen (NO{sub x}), and particulate matter that would be lower than Clean Air Act limits while at the same time producing power more efficiently and at less cost than conventional coal utilization technologies. JEA has indicated that construction may begin without DOE funding prior to the completion of the NEPA process in February 2000 and would continue until December 2001. Demonstration of the proposed project would be conducted during a 2-year period from March 2002 until March 2004. In addition, JEA plans to repower the currently operating Unit 1 steam turbine about 6 to 12 months after the Unit 2 repowering without cost-shared funding from DOE. Although the proposed project consists of only the Unit 2 repowering, this EIS analyzes the Unit 1 repowering as a related action. The EIS also considers three reasonably foreseeable scenarios that could result from the no-action alternative in which DOE would not provide cost-shared funding for the proposed project. The proposed action, in which DOE would provide cost-shared funding for the proposed project, is DOE's preferred alternative. The EIS evaluates the principal environmental

  13. Characterization of ashes from a 100 kWth pilot-scale circulating fluidized bed with oxy-fuel combustion

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.H.; Wang, C.B.; Tan, Y.W.; Jia, L.F.; Anthony, E.J. [Natural Resources Canada, Ottawa, ON (Canada)

    2011-09-15

    Oxy-fuel combustion experiments have been carried out on an oxygen-fired 100 kW(th) mini-circulating fluidized bed combustion (CFBC) facility. Coal and petroleum coke were used as fuel together with different limestones (and fixed Ca:S molar ratios) premixed with the fuel, for in situ SO{sub 2} capture. The bed ash (BA) and fly ash (FA) samples produced from this unit were collected and characterized to obtain physical and chemical properties of the ash samples. The characterization methods used included X-ray fluorescence (XRF), X-ray diffraction (XRD), char carbon and free lime analysis, thermogravimetric analysis (TGA), and surface analysis. The main purpose of this work is to characterize the CFBC ashes from oxy-fuel firing to obtain a better understanding of the combustion process, and to identify any significant differences from the ash generated by a conventional air-fired CFBC. The primary difference in the sulfur capture mechanism between atmospheric air-fired and oxy-fuel FBC, at typical FBC temperatures (similar to 850{sup o}C), is that, in the air-fired case the limestone sorbents calcine, whereas the partial pressure of CO{sub 2} in oxy-fuel FBC is high enough to prevent calcination, and hence the sulfation process should mimic that seen in pressurized FBC (PFBC). Here, the char carbon content in the fly ash was much higher than that in the bed ash, and was also high by comparison with ash obtained from conventional commercial air-firing CFBC units. In addition, measurements of the free lime content in the bed and fly ash showed that the unreacted Ca sorbent was present primarily as CaCO{sub 3}, indicating that sulfur capture in the oxy-fuel combustor occurred via direct sulfation.

  14. Steam gasification of coal cokes by internally circulating fluidized-bed reactor by concentrated Xe-light radiation for solar syngas production

    International Nuclear Information System (INIS)

    A laboratory-scale prototype windowed reactor using a fluidized bed of coal coke particles was tested for thermochemical gasification using concentrated Xe light radiation as an energy source. The fluidized-bed reactor, designed to be combined with a solar reflective tower or beam-down optics, is evaluated for steam gasification of coal coke according to gasification performance: CO, H2, and CO2 production rates; carbon conversion; light-to-chemical efficiency. Internal circulation of coal coke particles inside the reactor increases gasification performance, which is further enhanced by higher steam partial pressure of the inlet gas. - Highlights: • A reactor prototype was designed for solar steam gasification by beam-down optics. • Particle circulation homogenizes temperature distribution across all bed layers. • The reactor design of internal circulation improved gasification performances

  15. Synthesis of Linear Alkylbenzene in a Novel Liquid-Solid Circulating Moving Bed Reactor

    Institute of Scientific and Technical Information of China (English)

    韩明汉; 徐聪; 崔哲; 金涌

    2004-01-01

    For the alkylation of benzene with long-chain olefins, using Hβ zeolite catalyst as replacement of HF or A1Cl3 has the advantages of no corrosion, less environmental pollution, and much more 2-phenyl isomer, which has the highest biodegradability and solubility, and better detergent properties among the related isomers. The characterization of the coke shows that the deactivation of catalyst is caused by the jam of bulkier molecules, such as naphthalene, indane and linear alkylbenzenes, which are too big to move quickly in the intracrystalline pores of catalyst. The deactivated catalyst can be regenerated by benzene washing at higher temperature. To make the processes of reaction and regeneration continuous, a novel moving bed reactor is developed. Comparing with the processes with fixed bed reactors, the processes in this work have the advantages of continuous operation, low temperature, low pressure, low mole ratio of benzene to olefins, and high weight hourly space velocity.Keywords t3 zeolite, alkylation, linear alkylbenzene, moving bed reactor

  16. Hydrogen production by steam reforming of higher hydrocarbons in a novel circulating fluidized bed reactor-regenerator system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.; Elnashaie, S.; Yan, Y. [Auburn Univ., AL (United States). Dept. of Chemcial Engineering

    2003-07-01

    A mathematical model was developed to demonstrate the production of hydrogen by steam reforming of higher hydrocarbons in a circulating fluidized bed reactor-regenerator system (CFBRR). Heptane was the higher hydrocarbon used in this study. The process simulation of the riser steam reformer, catalyst regenerator, and downer indicate that the impact of catalyst deactivation is negligible because of the large mass flow ratio of solid to gas stream and the catalyst regenerator. The carbon deposited on the catalyst can be either gasified efficiently in the steam reformer or burned with air in the catalyst regenerator. The burning of carbon on the catalyst supplies the heat required for endothermic steam reforming of heptane and methane. This method has potential advantages for both energy consumption as well as hydrogen production.

  17. Climate effect of an integrated wheat production and bioenergy system with Low Temperature Circulating Fluidized Bed gasifier

    DEFF Research Database (Denmark)

    Sigurjonsson, Hafthor Ægir; Elmegaard, Brian; Clausen, Lasse Røngaard;

    2015-01-01

    integration between the agricultural system and the energy system through the Low Temperature Circulating Fluidized Bed (LT-CFB) gasifier from the perspective of wheat grain production and electricity generation using wheat straw, where the effects of removing the straw from the agricultural system...... based on carbon conversion to two references, no straw removal and straw combustion. The results show that the climate effect of removing the straws are mitigated by the carbon soil sequestration with biochar, and electricity and district heat substitution. Maximum biochar production outperforms maximum...... heat and power generation for most substituted electricity and district heating scenarios. Irrespective of the substituted technologies, the carbon conversion needs to be 80-86% to fully mitigate the effects of removing the straws from the agricultural system. This concludes that compromising on energy...

  18. N sub 2 O emission minimization in circulating fluidized bed. Kiertoleijupolton N sub 2 O-emissio ja sen minimointi

    Energy Technology Data Exchange (ETDEWEB)

    Peltola, K.; Hiltunen, M. (Ahlstroem Pyropower Co., Karhula (Finland). Hans Ahlstroem Lab.); Lee, Y.Y. (Ahlstroem Pyropower Inc., San Diego (USA). R and D Center)

    1991-01-01

    The objective of the project was to study the effect of the process variables on the N{sub 2}O emissions from Ahistrom Pyrof low circulating fluidized bed (CFB) boilers combusting coal, peat and mixed fuels. The objective was to optimize the combustion process on the basis of the analysis results and theoretical explanations in order to achieve minimum N{sub 2}O emissions and simultaneously to meet the other emission regulations (SO{sub 2}, NO{sub x}). The project included three commercial Pyrof low CFB boilers in Finland and five commercial boilers in the USA. The heat capacity of the boilers were from 30 MW to 136 MW. The N{sub 2}O emissions monitored were from 7 mg/MJ to 88 mg/MJ. Some tests were also made in the Pyrof low pilot plant.

  19. Experimental and mechanism studies on simultaneous desulfurization and denitrification from flue gas using a flue gas circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yi; XU PeiYao; SUN XiaoJun; WANG LiDong

    2007-01-01

    The oxidizing highly reactive absorbent was prepared from fly ash, industry lime, and an oxidizing additive M. Experiments of simultaneous desulfurization and denitrification were carried out in a flue gas circulating fluidized bed (CFB). The effects of influencing factors and calcium availability were also investigated on the removal efficiencies of desulfurization and denitrification. Removal efficiencies of 95.5% for SO2 and 64.8% for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods. The results indicated that more nitrogen species appeared in the spent absorbent except sulfur species. A scanning electron microscope (SEM) and an accessory X-ray energy spectrometer were used to observe micro-properties of the samples, including fly ash, oxidizing highly reactive absorbent and spent absorbent. The simultaneous removal mechanism of SO2 and NO based on this absorbent was proposed according to the experimental results.

  20. Effects of the updated national emission regulation in China on circulating fluidized bed boilers and the solutions to meet them.

    Science.gov (United States)

    Li, Jingji; Yang, Hairui; Wu, Yuxin; Lv, Junfu; Yue, Guangxi

    2013-06-18

    The advantage of circulating fluidized bed (CFB) boilers in China is their ability to utilize low rank coal with low cost emission control. However, the new National Emission Regulation (NER) issued in early 2012 brings much more stringent challenges on the CFB industries, which also causes much attention from other countries. Based on the principle of a CFB boiler and previous operating experience, it is possible for the CFB boilers to meet the new NER and maintain the advantage of low cost emission control, while, more influences should be considered in their design and operation. To meet the requirement of the new NER, the fly ash collector should adopt a bag house or combination of electrostatic precipitator and bag filter to ensure dust emissions of less than 30 mg · Nm(-3). For SO2 emission control, the bed temperature should be strictly lower than 900 °C to maintain high reactivity and pores. The limestone particle size distribution should be ranged within a special scope to optimize the residence time and gas-solid reaction. At the same time, the injecting point should be optimized to ensure fast contact of lime with oxygen. In such conditions, the desulfurization efficiency could be increased more than 90%. For lower sulfur content fuels (selective non-catalytic reduction (SNCR) should be considered. Due to the unique temperature in CFB as well as the circulating ash, the efficiency of SNCR could reach as high as 70%. The Hg emission of CFB is very low for the new NER due to its innate property.

  1. 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. PMID:26278370

  2. Soy protein recovery in a solvent-free process using continuous liquid-solid circulating fluidized bed ion exchanger.

    Science.gov (United States)

    Prince, Andrew; Bassi, Amarjeet S; Haas, Christine; Zhu, Jesse X; Dawe, Jennifer

    2012-01-01

    Soy protein concentrates and soy protein isolates act as ingredients in bakery, meat and dairy products, baby formulas, starting materials for spun textured vegetable products, and other nutritional supplements. In this study, the effectiveness of a liquid-solid circulating fluidized bed (LSCFB) ion exchanger is demonstrated for the recovery of soluble soy proteins from full fat and defatted soy flour. Under steady-state operating conditions, about 50% of the proteins could be recovered from the feed streams entering the ion exchanger. The LSCFB was shown to be a promising system for the recovery of soy protein from both defatted and full fat soy flour solutions. As the ion exchange process captures dissolved proteins, the system may offer a less damaging form of processing compared with the acid precipitation process where soy protein aggregates form and functionality is affected. In addition, the LSCFB allows simultaneous adsorption and desorption of the proteins allowing for a continuous operation. No prefiltration of feed containing suspended particles is required as well, because fluidization is used in place of packed bed technology to improve on current ion exchange processes. PMID:22002948

  3. Circulating fluidized bed combustion product addition to acid soil: alfalfa (Medicago sativa L.) composition and environmental quality.

    Science.gov (United States)

    Chen, Liming; Dick, Warren A; Kost, David

    2006-06-28

    To reduce S emissions, petroleum coke with a high concentration of S was combusted with limestone in a circulating fluidized bed (CFB) boiler. The combustion process creates a bed product that has potential for agricultural uses. This CFB product is often alkaline and enriched in S and other essential plant nutrients, but also contains high concentrations of Ni and V. Agricultural land application of CFB product is encouraged, but little information is available related to plant responses and environmental impacts. CFB product and agricultural lime (ag-lime) were applied at rates of 0, 0.5, 1.0, and 2.0 times the soil's lime requirement (LR) to an acidic soil (Wooster silt loam). The 2.0x LR application rate of CFB product was equivalent to 67.2 Mg ha(-1). Alfalfa yield was increased 4.6 times by CFB product and 3.8 times by ag-lime compared to untreated control. Application of CFB product increased the concentration of V in soil and alfalfa tissue, but not in soil water, and increased the concentration of Ni in soil and soil water, but not in alfalfa tissue. However, these concentrations did not reach levels that might cause environmental problems.

  4. FLOW STRUCTURE FORMATION AND EVOLUTION IN CIRCULATING GAS-FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    Jie Li; J. A. M. Kuipers

    2004-01-01

    The occurrence of heterogeneous flow structures in gas-particle flows seriously affects the gas-solid contacting and transport processes in high-velocity gas-fluidized beds. Particles do not disperse uniformly in the flow but pass through the bed in a swarm of clusters. The so-called "core-annulus" structure in the radial direction and "S" shaped axial distribution of solids concentration characterize the typical flow structure in the system.A computational study, using the discrete particle approach based on molecular dynamics techniques, has been carried out to explore the mechanisms underlying formation of the clusters and the core-annulus structure. Based on energy budget analysis including work done by the drag force, kinetic energy, rotational energy, potential energy, and energy dissipation due to particle-particle and particle-wall collisions, the role of gas-solid interaction and inelastic collisions between the particles are elucidated.It is concluded that the competition between gas-solid interaction and particle-particle interaction determines the pattern formation in high-velocity gas-solid flows: if the gas-solid interaction (under elevated pressure) dominates, most of particle energy obtained by drag from the gas phase is partitioned such that particle potential energy is raised, leading to a uniform flow structure. Otherwise, a heterogeneous pattern exists, which could be induced by both particle-particle collisions and gas-solid interaction. Although both factors could cause the flow instability, the non-linear drag force is demonstrated to be the necessary condition to trigger heterogeneous flow structure formation. As gas velocity increases and goes beyond a critical value, the fluid-particle interaction suppresses particle collisional dissipation, and as a consequence a more homogeneous flow regime is formed.

  5. Hydrolysis, acidification and methanogenesis during low-temperature anaerobic digestion of dilute dairy wastewater in an inverted fluidised bioreactor.

    Science.gov (United States)

    Bialek, Katarzyna; Cysneiros, Denise; O'Flaherty, Vincent

    2014-10-01

    The application of low-temperature (10 °C) anaerobic digestion (LtAD) for the treatment of complex dairy-based wastewater in an inverted fluidised bed (IFB) reactor was investigated. Inadequate mixing intensity provoked poor hydrolysis of the substrate (mostly protein), which resulted in low chemical oxygen demand (COD) removal efficiency throughout the trial, averaging ~69 % at the best operational period. Overgrowth of the attached biomass to the support particles (Extendospheres) induced bed stratification by provoking agglutination of the particles and supporting their washout by sedimentation, which contributed to unstable bioprocess performance at the organic loading rates (OLRs) between 0.5 and 5 kg COD m(-3) day(-1). An applied OLR above 2 kg COD m(-3) day(-1) additionally promoted acidification and strongly influenced the microbial composition and dynamics. Hydrogenotrophic methanogens appeared to be the mostly affected group by the Extendospheres particle washout as a decrease in their abundance was observed by quantitative PCR analysis towards the end of the trial, although the specific methanogenic activity and maximum substrate utilisation rate on H2/CO2 indicated high metabolic activity and preference towards hydrogenotrophic methanogenesis of the reactor biomass at this stage. The bacterial community in the bioreactor monitored via denaturing gradient gel electrophoresis (DGGE) also suggested an influence of OLR stress on bacterial community structure and population dynamics. The data presented in this work can provide useful information in future optimisation of fluidised reactors intended for digestion of complex industrial wastewaters during LtAD.

  6. An experimental study of the hydrodynamics and cluster formation in a circulating fluidized bed. Topical report, January 1, 1991--June 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, M.; Jurewicz, J.; Heping, Y.; Clifton, K.

    1992-07-01

    This research program involves two major aspects. First, to evaluate techniques to effectively probe the polydisperse gas-solid flows and second, to apply these techniques to study the gas-solid flow structure and clusters in the riser of a circulating fluidized bed riser. Amongst the non-intrusive techniques a modified laser Doppler technique based on the fluorescence-emission concept has been adopted and the other techniques involve pitot-static pressure probes. A circulating fluidized bed (CFB) facility has been designed, built and is currently operational at West Virginia University. The design provides for maximum versatility in investigating the hydrodynamics of the CFB riser. Two stage cyclones are employed to capture the particles exhausted from the riser. Measurements of gas velocity distribution were carried out in the circulating fluidized bed riser. with particles having a mean diameter of 112 {mu}m and a density of 2305 kg/m{sup 3} and another set of particles with a mean diameter of 145 {mu}m and a density of 2245 kg/m{sup 3}. The experimental results showed that the local gas velocity varied with the radial position, elevation, solids circulation rate, superficial velocity and particle size. A general formula for gas velocity distribution in the circulating fluidized bed riser was obtained based on the particle circulation, superficial velocity and particle diameter. The pressure drops across the L-valve were also studied for different particle sizes, L-valve diameters and aeration. The solids flowrate was found to be a function of the L-valve geometry, operating parameters and solids properties. Pressure drop of L-valve increases with increasing solids diameter and decreasing diameter of the L-valve. Pressure drop across standpipe increases as the solids diameter and diameter of the standpipe decrease.

  7. Experiences in sulphur capture in a 30 MWth Circulating Fluidized Bed boiler under oxy-combustion conditions

    International Nuclear Information System (INIS)

    CO2 and SO2 from fossil fuel combustion are contributors to greenhouse effect and acid rain respectively. Oxy-combustion technology produces a highly concentrated CO2 stream almost ready for capture. Circulating Fluidized Bed (CFB) boiler technology allows in-situ injection of calcium-based sorbents for efficient SO2 capture. CIUDEN's 30 MWth CFB boiler, supplied by Foster Wheeler and located at the Technology Development Centre for CO2 Capture and Transport (es.CO2) in Spain, is the first of its kind for executing test runs at large pilot scale under both air-combustion and oxy-combustion conditions. In this work, SO2 emissions under different scenarios have been evaluated. Variables such as limestone composition, Ca/S molar ratio and bed temperature among others have been considered along different test runs in both air-combustion and oxy-combustion conditions to analyse its influence on SO2 abatement. Fly and bottom ash, together with flue gas analysis have been carried-out. Desulphurization performance tests results are presented. - Highlights: •Sulphur capture efficiency (%) was higher in oxy-combustion compared to air-combustion in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. •For a Ca/S molar ratio higher than 2.6 there was barely any improvement on sulphur capture efficiency for both air-combustion and oxy-combustion conditions in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. •Optimum temperature for sulphur capture at a fixed Ca/S molar ratio is around 880–890 °C under oxy-combustion conditions and for anthracite coal with limestone as sorbent in a 30 MW thermal CFB boiler

  8. Influence of Sorbent Characteristics on Fouling and Deposition in Circulating Fluid Bed Boilers Firing High Sulfur Indian Lignite

    Directory of Open Access Journals (Sweden)

    Selvakumaran Palaniswamy

    2013-01-01

    Full Text Available 125 MWe circulating fluidized bed combustion (CFBC boiler experienced severe fouling in backpass of the boiler leading to obstruction of gas flow passage, while using high sulfur lignite with sorbent, calcium carbonate, to capture sulfur dioxide. Optical microscopy of the hard deposits showed mainly anhydrite (CaSO4 and absence of intermediate phases such as calcium oxide or presence of sulfate rims on decarbonated limestone. It is hypothesized that loose unreacted calcium oxides that settle on tubes are subjected to recarbonation and further extended sulfation resulting in hard deposits. Foul probe tests were conducted in selected locations of backpass for five different compositions of lignite, with varied high sulfur and ash contents supplied from the mines along with necessary rates of sorbent limestone to control SO2, and the deposits build-up rate was determined. The deposit build-up was found increasing, with increase in ash content of lignite, sorbent addition, and percentage of fines in limestone. Remedial measures and field modifications to dislodge deposits on heat transfer surfaces, to handle the deposits in ash conveying system, and to control sorbent fines from the milling circuit are explained.

  9. Investigation of gas-solids flow in a circulating fluidized bed using 3D electrical capacitance tomography

    Science.gov (United States)

    Mao, Mingxu; Ye, Jiamin; Wang, Haigang; Yang, Wuqiang

    2016-09-01

    The hydrodynamics of gas-solids flow in the bottom of a circulating fluidized bed (CFB) are complicated. Three-dimensional (3D) electrical capacitance tomography (ECT) has been used to investigate the hydrodynamics in risers of different shapes. Four different ECT sensors with 12 electrodes each are designed according to the dimension of risers, including two circular ECT sensors, a square ECT sensor and a rectangular ECT sensor. The electrodes are evenly arranged in three planes to obtain capacitance in different heights and to reconstruct the 3D images by linear back projection (LBP) algorithm. Experiments were carried out on the four risers using sands as the solids material. The capacitance and differential pressure are measured under the gas superficial velocity from 0.6 m s-1 to 3.0 m s-1 with a step of 0.2 m s-1. The flow regime is investigated according to the solids concentration and differential pressure. The dynamic property of bubbling flows is analyzed theoretically and the performance of the 3D ECT sensors is evaluated. The experimental results show that 3D ECT can be used in the CFB with different risers to predict the hydrodynamics of gas-solids bubbling flows.

  10. Development of Methane and Nitrous Oxide Emission Factors for the Biomass Fired Circulating Fluidized Bed Combustion Power Plant

    Directory of Open Access Journals (Sweden)

    Chang-Sang Cho

    2012-01-01

    Full Text Available This study makes use of this distinction to analyze the exhaust gas concentration and fuel of the circulating fluidized bed (CFB boiler that mainly uses wood biomass, and to develop the emission factors of Methane (CH4, Nitrous oxide (N2O. The fuels used as energy sources in the subject working sites are Wood Chip Fuel (WCF, RDF and Refused Plastic Fuel (RPF of which heating values are 11.9 TJ/Gg, 17.1 TJ/Gg, and 31.2 TJ/Gg, respectively. The average concentrations of CH4 and N2O were measured to be 2.78 ppm and 7.68 ppm, respectively. The analyzed values and data collected from the field survey were used to calculate the emission factor of CH4 and N2O exhausted from the CFB boiler. As a result, the emission factors of CH4 and N2O are 1.4 kg/TJ (0.9–1.9 kg/TJ and 4.0 kg/TJ (2.9–5.3 kg/TJ within a 95% confidence interval. Biomass combined with the combustion technology for the CFB boiler proved to be more effective in reducing the N2O emission, compared to the emission factor of the CFB boiler using fossil fuel.

  11. A Study on Methane and Nitrous Oxide Emissions Characteristics from Anthracite Circulating Fluidized Bed Power Plant in Korea

    Directory of Open Access Journals (Sweden)

    Seehyung Lee

    2012-01-01

    Full Text Available In order to tackle climate change effectively, the greenhouse gas emissions produced in Korea should be assessed precisely. To do so, the nation needs to accumulate country-specific data reflecting the specific circumstances surrounding Korea’s emissions. This paper analyzed element contents of domestic anthracite, calorific value, and concentration of methane (CH4 and nitrous oxide (N2O in the exhaust gases from circulating fluidized bed plant. The findings showed the concentration of CH4 and N2O in the flue gas to be 1.85 and 3.25 ppm, respectively, and emission factors were 0.486 and 2.198 kg/TJ, respectively. The CH4 emission factor in this paper was 52% lower than default emission factor presented by the IPCC. The N2O emission factor was estimated to be 46% higher than default emission factor presented by the IPCC. This discrepancy can be attributable to the different methods and conditions of combustion because the default emission factors suggested by IPCC take only fuel characteristics into consideration without combustion technologies. Therefore, Korea needs to facilitate research on a legion of fuel and energy consumption facilities to develop country-specific emission factors so that the nation can have a competitive edge in the international climate change convention in the years to come.

  12. Experimental and mechanism studies on simultaneous desulfurization and denitrification from flue gas using a flue gas circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The oxidizing highly reactive absorbent was prepared from fly ash,industry lime,and an oxidizing additive M.Experiments of simultaneous desulfurization and denitrification were carried out in a flue gas circulating fluidized bed(CFB).The effects of influencing factors and calcium availability were also investigated on the removal efficiencies of desulfurization and denitrification.Removal efficiencies of 95.5%for SO2 and 64.8%for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods.The results in- dicated that more nitrogen species appeared in the spent absorbent except sulfur species.A scanning electron microscope(SEM)and an accessory X-ray energy spectrometer were used to observe micro-properties of the samples,including fly ash,oxidizing highly reactive absorbent and spent absorbent.The simultaneous removal mechanism of SO2 and NO based on this absorbent was pro- posed according to the experimental results.

  13. Development of methane and nitrous oxide emission factors for the biomass fired circulating fluidized bed combustion power plant.

    Science.gov (United States)

    Cho, Chang-Sang; Sa, Jae-Hwan; Lim, Ki-Kyo; Youk, Tae-Mi; Kim, Seung-Jin; Lee, Seul-Ki; Jeon, Eui-Chan

    2012-01-01

    This study makes use of this distinction to analyze the exhaust gas concentration and fuel of the circulating fluidized bed (CFB) boiler that mainly uses wood biomass, and to develop the emission factors of Methane (CH(4)), Nitrous oxide (N(2)O). The fuels used as energy sources in the subject working sites are Wood Chip Fuel (WCF), RDF and Refused Plastic Fuel (RPF) of which heating values are 11.9 TJ/Gg, 17.1 TJ/Gg, and 31.2 TJ/Gg, respectively. The average concentrations of CH(4) and N(2)O were measured to be 2.78 ppm and 7.68 ppm, respectively. The analyzed values and data collected from the field survey were used to calculate the emission factor of CH(4) and N(2)O exhausted from the CFB boiler. As a result, the emission factors of CH(4) and N(2)O are 1.4 kg/TJ (0.9-1.9 kg/TJ) and 4.0 kg/TJ (2.9-5.3 kg/TJ) within a 95% confidence interval. Biomass combined with the combustion technology for the CFB boiler proved to be more effective in reducing the N(2)O emission, compared to the emission factor of the CFB boiler using fossil fuel. PMID:23365540

  14. Hydrodynamique, transfert de chaleur et combustion de gaz naturel en lit fluidisé circulant Hydrodynamics, Heat Transfer and Combustion of Natural Gas in a Circulating Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Feugier A.

    2006-11-01

    Full Text Available L'hydrodynamique, les transferts de chaleur et la combustion du gaz naturel ont été étudiés dans un réacteur à lit circulant de 15 cm de diamètre et de 7 m de haut. Ce réacteur peut opérer avec des vitesses de gaz allant jusqu'à 15 m/s, jusqu'à des températures de 880-900°C et avec des débits de solides compris entre 0 et 15t/h. Les charges utilisées sont des sables de granulométrie allant de 95 à 625 microns. Le profil de concentration en solides dans le réacteur est déterminé à partir du profil de pression. Une corrélation reliant la vitesse de glissement des particules aux principaux paramètres opératoires, rend compte de façon très satisfaisante de l'ensemble des résultats expérimentaux. La mise en place d'un échangeur en paroi dans la partie supérieure du réacteur a permis la détermination de coefficients d'échange thermique. Ces derniers sont essentiellement fonction de la, concentration en particules au droit de l'échangeur et de la granulométrie des particules. Des valeurs allant jusqu'à 200 W/m2 K peuvent, être obtenues. Enfin, la combustion du méthane s'avère très sensible à la présence de particules dans le réacteur. Ces particules ont un effet inhibiteur. Hydrodynamics, heat transfer and combustion of natural gas have been investigated in a circulating-bed reactor 15 cm in diameter and 7 m high. This reactor can operate with gas velocities up to 15 m/s, at temperature up to 880-900°C and with solids flow rates of between 0 and 15 t/h. The solids used are sands with a particle size ranging from 95 to 625 microns. The solids concentration profile in the reactor is determined from the pressure profile. A correlation linking the slippage velocity of particles to the principal operating parameters very satisfactorily takes into consideration the overall experimental results. The installation of a wall heat exchanger in the upper part of the reactor enabled the heat exchange coefficients to be

  15. Experimental findings on thermal use of residues and biofuels in circulating fluidized bed combustion systems; Experimentelle Ergebnisse zur thermischen Nutzung von Rest- und Biobrennstoffen in zirkulierenden Wirbelschichtfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, W.; Brunne, T.; Girndt, H. [Technische Univ. Dresden (Germany); Albrecht, J. [Lurgi Lentjes Babcock, Frankfurt am Main (Germany); Youssef, M. [Minia Univ. (Egypt)

    1996-12-31

    The energy Engineering Institute of Dresden Technical University investigated the combustion and emission characteristics of a number of combustion systems, including a circulating fluidized bed system with a capacity of 0.3 MW{sub th}. Egypt`s sugar cane industry produces large volumes of bagasse. The conbustion and emission characteristics of this biofuel in a circulating fludized bed combustion systems were investigated in a joint research project of the University of Minia and Dresden Technical University. (orig.) [Deutsch] Am Institut fuer Energietechnik der TU Dresden wird das Verbrennungs- und Emissionsverhalten verschiedenster Brennstoffe in unterschiedlichen Feuerungssystemen untersucht. Neben anderen Pilotanlagen steht eine zirkulierende Wirbelschichtfeuerung (ZWFS) mit einer Leistung von 0.3 MW{sub th} zur Verfuegung. In der Zuckerrohrindustrie Aegyptens fallen grosse Mengen von Bagasse an. In einer gemeinsamen Forschungsarbeit zwischen der Universitaet Minia und der TU Dresden sollte das Verbrennungs- und Emissionsverhalten dieses Biobrennstoffes in einer ZWSF untersucht werden. (orig)

  16. Emission characteristics of co-combustion of sewage sludge with olive cake and lignite coal in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Toraman, O.Y.; Topal, H.; Bayat, O.; Atimtay, A.T. [Middle East Technical University, Ankara (Turkey). Dept. of Environmental Engineering

    2004-07-01

    In this study, a circulating fluidized bed (CFB) of 125 mm diameter and 1800 trim height was used to find the combustion characteristics of sewage sludge (SS) produced in Turkey. Sludge + olive cake, and Sludge + lignite coal mixtures were burned separately. Various sludge-to-lignite coal and sludge-to-olive cake ratios (5/95, 10/90. 15/85, 20/80) were tried. On-line concentrations of major components (O{sub 2}, SO{sub 2}, CO{sub 2}, CO, NOx, C{sub m}H{sub n}) were measured in the flue gas, as well as temperature and pressure distributions along the bed. Combustion efficiencies of sludge + olive cake and sludge + lignite coal mixtures were calculated, and the optimum conditions for operating parameters were discussed. The results have shown that the combustion mainly takes place in the upper regions of the main column where the temperature reaches 900 C. SS + coal burn in the CFB with an efficiency of 95.14% to 96.18%, which is considered to be quite good. When burning sludge mixed with olive cake, appreciable amounts of CO and unburned hydrocarbons are formed and the combustion efficiency drops to 92.93%. CO and C{sub m}H{sub n} emissions are lower when lignite coal is mixed with various amounts of SS than the. emissions when the coal is burned alone. As the %SS is increased in the fuel mixture, the SO{sub 2} emission decreases. NOx emissions are slightly higher. When burning sludge mixed with olive cake, SO{sub 2} and NOx emissions are slightly higher. CO and C{sub m}H{sub n} emissions decrease sharply when SS is mixed with 5%wt. olive cake. With increasing sludge ratio these emissions increase due to the unburned hydrocarbons. As a result of this study, it is believed that SS can be burned effectively in a CFBC together with other fuels, especially with olive cake (OC). OC will be a good additive fuel for the combustion of lower quality fuels.

  17. Experimental study on fuel oil combustion in circulating fluidized bed; Estudio experimental sobre la combustion de combustoleo en lecho fluidizado circulante

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Rangel, Ricardo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The Instituto de Investigaciones Electricas (IIE) developed a circulating fluidized bed combustor of 0.5 thermal MW unique in its type in Latin America. The Bachelor`s thesis entitled ``Experimental Study on Fuel Oil Combustion in Circulating Fluidized Bed`` was performed operating this combustor with the purpose of determining the feasibility of burning heavy fuel oil in a stable and sustained form, as well as the effect of the addition of calcium carbonate to the combustor. The results of the experimental trials showed heavy fuel oil can be burned in a circulating fluidized bed, with low sulfur dioxide emissions. During the conduction of the experiments a sulfur retention of 43% was achieved with a Ca/S relationship of 4.5. [Espanol] El Instituto de Investigaciones Electricas (IIE) desarrollo un combustor de lecho fluidizado circulante de 0.5 MW termicos de potencia, unico en su tipo en Latinoamerica. La tesis de licenciatura titulada Estudio Experimental sobre la Combustion de Combustoleo en Lecho Fluidizado Circulante se realizo operando dicho combustor, con el proposito de determinar la factibilidad de quemar combustoleo pesado en forma estable y autosostenida, asi como la influencia que tiene la adicion de carbonato de calcio al lecho. Los resultados de los ensayos experimentales mostraron que se puede quemar combustoleo pesado en un lecho fluidizado circulante, con bajas emisiones de bioxido de azufre. Durante la experimentacion se logro una retencion de azufre del 43%, con una relacion Ca/S de 4.5.

  18. THE EXPERIMENTAL STUDY OF COMBUSTION STABILITY IN THE INTERNAL CIRCULATING FLUIDIZED BED%内旋流流化床燃烧稳定性研究

    Institute of Scientific and Technical Information of China (English)

    田文栋; 魏小林; 黎军; 吴东垠; 盛宏至

    2001-01-01

    Invariable and even combustion temperature is necessary for the municipal solid waste (MSW) incineration to decrease the emission of air pollutants. In thispaper, The combustion temperature stability in the dense phase bed zone and temperature distributions in the incinerator have been studied by adjustin gmass of processed waste, types of waste and particles thickness of bed in theinternal circulating fluidized bed (ICFB).%城市生活垃圾焚烧需要稳定均匀的温度来减少燃烧产生的大气污染物。采用内旋流流化床进行了垃圾焚烧实验,通过改变垃圾处理量、垃圾种类和流化床浓相床区高度,研究了浓相床区温度的稳定性和焚烧炉内温度分布。

  19. Stearic acid coating on circulating fluidized bed combustion fly ashes and its effect on the mechanical performance of polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Nina [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Zhang, Ping, E-mail: pingzhang@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010 (China); Song, Lixian; Kang, Ming; Lu, Zhongyuan [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010 (China); Zheng, Rong [Sichuan Jinhe Group Co., Ltd., Mianyang 621010 (China)

    2013-08-15

    The aim of this work was to test circulating fluidized bed combustion fly ashes (CFAs) for its potential to be utilized in polymer composites manufacturing to improve its toughness. CFAs was coated by stearic acid and used in the composite of polypropylene/ethylene vinyl acetate/high density polyethylene (PP/EVA/HDPE) by molding process method. The resulting coated and uncoated CFAs were fully characterized by particle size analyzer, contact angles, powder X-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TGA/DTA), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The stearic acid coated onto the surface of CFAs particles in the physical and chemical ways, and the total clad ratio reached 2.05% by measuring TGA/DTA curve. The percentage of CFAs particles focused to a narrow range 2–4 μm and the median mean size was 3.2 μm more than uncoated CFAs. The properties of hydrophobic and dispersive of CFAs particles improved and original activity was reserved after stearic acid coating. The stearic acid was verified as a coupling agent by how much effect it had on the mechanical properties. It showed the elongation at break of PP/EVA/HDPE reinforced with 15 wt% coated CFAs (c-CFAs) was 80.20% and higher than that of the uncoated. The stearic acid treatment of CFAs is a very promising approach to improve the mechanical strength due to the incorporation of stearic acid on the CFAs surface, and hence, further enhances the potential for recycling CFAs as a suitable filler material in polymer composites.

  20. Batch top-spray fluid bed coating: Scale-up insight using dynamic heat- and mass-transfer modelling

    DEFF Research Database (Denmark)

    Hede, Peter Dybdahl; Bach, P.; Jensen, Anker Degn

    2009-01-01

    volumes. In each control volume, dynamic heat and mass balances were set up allowing the simulation of the contents of water vapour, water on core particles and deposited coating mass as well as fluidisation gas, particle and chamber wall temperature. The model was used to test different scale......A mathematical model was developed for batch top-spray fluid bed coating processes based on Ronsse et al. [2007a.b. Combined population balance and thermodynamic modelling of the batch top-spray fluidised bed coating process. Part I-model development and validation. journal of Food Engineering 78......, 296-307; Combined population balance and thermodynamic modelling of the batch top-spray fluidised bed coating process. Part II-model and process analysis. journal of Food Engineering 78, 308-322]. The model is based on one-dimensional discretisation of the fluid bed into a number of well-mixed control...

  1. Characteristics of axial and radial segregation of single and mixed particle system based on terminal settling velocity in the riser of a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-12-15

    Axial and radial segregation and mixing of single and mixed particle systems were studied for the various sizes and densities in a 10.16cm diameter riser of a circulating fluidized bed (CFB) based on terminal settling velocity of particles. The gas velocities were maintained in the range of 2.01-4.681 m/s and solid circulation rate between 12.5 and 50 kg/m{sup 2}s. Three quartz sand-FCC catalyst mixtures with different initial weight % of sand and two coal-iron ore mixtures were used. The difference in local mean particle sizes of the components of the binary mixture has been observed in the riser of a CFB. Due to the larger mean particle size of sand and due to their lower solid density, the measured particle sizes of this fraction show higher values than FCC. For the same size of bed materials consisting of coal and iron ore mixture the variation of the mean particle size for both has been found to be very narrow. Again the axial segregation for the coal/iron ore mixture has been studied in terms of terminal settling velocity of the particles. The result showed a continuous classification of bed materials along the riser of a CFB.

  2. Convection and segregation in fluidised granular systems exposed to two-dimensional vibration

    Science.gov (United States)

    Windows-Yule, C. R. K.

    2016-03-01

    Convection and segregation in granular systems not only provide a rich phenomenology of scientifically interesting behaviours but are also crucial to numerous ‘real-world’ processes ranging from important and widely used industrial procedures to potentially cataclysmic geophysical phenomena. Simple, small-scale experimental or simulated test systems are often employed by researchers in order to gain an understanding of the fundamental physics underlying the behaviours of granular media. Such systems have been the subject of extensive research over several decades, with numerous system geometries and manners of producing excitation explored. Energy is commonly provided to granular assemblies through the application of vibration—the simplicity of the dynamical systems produced and the high degree of control afforded over their behaviour make vibrated granular beds a valuable canonical system by which to explore a diverse range of phenomena. Although a wide variety of vibrated systems have been explored in the existing literature, the vast majority are exposed to vibration along only a single spatial direction. In this paper, we study highly fluidised systems subjected to strong, multi-directional driving, providing a first insight into the dynamics and behaviours of these systems which may potentially hold valuable new information relevant to important industrial and natural processes. With a particular focus on the processes of convection and segregation, we analyse the various states and phase transitions exhibited by our system, detailing a number of previously unobserved dynamical phenomena and system states.

  3. 气-液-固三相循环流化床中的液相轴向扩散%Axial Liquid Dispersion in Gas-Liquid-Solid Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    M. Vatanakul; 孙国刚; 郑莹; M. Couturier

    2005-01-01

    The effects of liquid viscosities, solid circulating rates, liquid and gas velocities and phase holdups on the axial dispersion coefficient, Dax, were investigated in a gas-liquid-solid circulating fluidized bed (GLSCFB).Liquid viscosity promotes the axial liquid backmixing when solid particles and gas bubbles are present. Increases in gas velocities and solid circulating rates lead to higher Dax. The effects of liquid velocity on Dax are associated with liquid viscosity. Compared with conventional expanded beds, the GLSCFBs hold less axial liquid dispersion,approaching ideal plug-flow reactors.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bruce G. Miller; Sharon Falcone Miller; Robert Cooper; John Gaudlip; Matthew Lapinsky; Rhett McLaren; William Serencsits; Neil Raskin; Tom Steitz; Joseph J. Battista

    2003-03-26

    The Pennsylvania State University, utilizing funds furnished by the U.S. Department of Energy's Biomass Power Program, investigated the installation of a state-of-the-art circulating fluidized bed boiler at Penn State's University Park campus for cofiring multiple biofuels and other wastes with coal, and developing a test program to evaluate cofiring biofuels and coal-based feedstocks. The study was performed using a team that included personnel from Penn State's Energy Institute, Office of Physical Plant, and College of Agricultural Sciences; Foster Wheeler Energy Services, Inc.; Foster Wheeler Energy Corporation; Parsons Energy and Chemicals Group, Inc.; and Cofiring Alternatives. The activities included assessing potential feedstocks at the University Park campus and surrounding region with an emphasis on biomass materials, collecting and analyzing potential feedstocks, assessing agglomeration, deposition, and corrosion tendencies, identifying the optimum location for the boiler system through an internal site selection process, performing a three circulating fluidized bed (CFB) boiler design and a 15-year boiler plant transition plan, determining the costs associated with installing the boiler system, developing a preliminary test program, determining the associated costs for the test program, and exploring potential emissions credits when using the biomass CFB boiler.

  5. Investigation on SO{sub 2} emission from 410t/h circulating fluidized bed boiler burning petroleum coke and coal

    Energy Technology Data Exchange (ETDEWEB)

    Lun-Bo Duan; Xiao-Ping Chen; Ying-Jie Li; Cai Liang; Chang-Sui Zhao [Southeast University, Nanjing (China). Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education

    2010-03-15

    Effects of operation parameters including bed temperature, Ca/S molar ratio, excess air coefficient, fly ash recirculation rate and limestone microstructure on SO{sub 2} emission were investigated on a 410t/h circulating fluidized bed (CFB) boiler burning petroleum coke and coal. Results show that for different fuels, SO{sub 2} emission is correspondingly related to the sulfur content in it under the same operation conditions. With increasing bed temperature, SO{sub 2} concentration in the flue gas reduces first and then increases. There is an optimal desulfurization temperature. For burning bituminous coal (BC) only or 70% BC + 30% petroleum coke (PC), the optimal desulfurization temperature is about 850{sup o}C, while it is about 850-870{sup o}C for burning 50% anthracite (AN) + 50% PC. SO{sub 2} emission decreases with the increase in Ca/S ratio, excess air coefficient and fly ash recirculation rate. Microstructure of limestone has distinct effects on their SO{sub 2} retention capacity, and larger specific surface area and higher specific pore volume lead to stronger SO{sub 2} capture activities. The optimal temperature, Ca/S ratio and excess air coefficient for different fuels are recommended for industrial application.

  6. 循环流化床生物质气化炉内计算流体动力学模拟--鼓泡流化床内改进的颗粒床模型%CFD simulation in a circulating fluidized-bed biomass gasifier--A modified particle bed model in bubbling fluidized beds

    Institute of Scientific and Technical Information of China (English)

    张锴; BRANDANI Stefano

    2005-01-01

    The circulating fluidized-bed gasification is a potential industrial technology for high efficient utilization of biomass in middle- and large-scaled power stations. A fast internally circulating fluidized-bed steam gasification technology has developed to obtain a high-grade synthesis gas without using pure O2. Some demonstration and/or commercial plants supported by European Union and its members are in underway. Computational fluid dynamics (CFD), an alternative method to the step-by-step experimental scale-up, is employed to simulate a laboratory-sized cold set-up in this paper. A modified particle-bed model has been attempted to investigate the fluid dynamic stability of gas-solid system in the bubbling fluidized bed. Superficial gas velocity is one of vital factors to influence the dynamic flow behaviour and pressure fluctuation. The bubble number and the size of the bubble increase with an increase of superficial gas velocity. Pressure fluctuation becomes higher with increasing inlet gas velocity. The higher gas velocity is and the greater time-averaged pressure drop is. Solid circulation is a single-cell pattern in the fast internally circulating fluidized bed. These results appear in good agreement with the experiments, which will be helpful for scaling up and designing the fast internally circulating fluidized-bed biomass gasifier.%采用改进颗粒床模型的CFD方法模拟了实验室规模冷模装置内鼓泡床的流体流动时空特性.模拟结果表明表观气速是影响气固动态特征和压力波动的主要因素之一:随表观气速的增大,气泡数目增加,气泡体积增大,压力波动增强;气速越高时均压降越大;在内循环鼓泡流化床内固体颗粒呈"单室"流型.上述与实验观察相吻合的模拟结果将有助于放大和设计商业化的内循环流化床生物质气化炉.

  7. Influence factors of carbon content in fly ash in circulating fluidized bed boiler%CFB锅炉飞灰含碳量影响因素分析

    Institute of Scientific and Technical Information of China (English)

    索疆舜; 崔志刚; 马素霞; 贾建东; 王慧; 骆丁玲; 刘建华

    2016-01-01

    Taking a 300 MW unit circulating fluidized bed (CFB)boiler as an example,the influencing factor coefficient analysis method was employed to investigate the effects of several operation parameters on car-bon content of fly ash under conditions with different loads and variable load,such as the coal particle size, the pressure ratio of the secondary air outlet pressure to pressure drop in dense phase zone,the oxygen con-tent at the economizer outlet,the ratio of the primary air volume to the secondary air volume,and the bed temperature.The results show that,the ratio of the secondary air outlet pressure to pressure drop in dense phase zone,and the ratio of the primary air volume to the secondary air volume,have greater influence on the carbon content of the fly ash.While the oxygen content at the economizer outlet and the bed tempera-ture (880~930 ℃)have relatively lower one.The results of this study provide guidance for the adjustment of combustion underpants leg type circulating fluidized bed boiler.%针对某电厂300 MW双支腿循环流化床(CFB)锅炉,基于影响因子系数分析方法,研究不同负荷下及负荷变化时入炉煤颗粒粒径、二次风出口压力与密相区压降比(p1/Δp)、省煤器出口氧量、一二次风量比和床温对飞灰含碳量的影响。结果表明:二次风出口压力与密相区压降比和一二次风量比对飞灰含碳量的影响程度较大,而省煤器出口氧量和床温(880~930℃)的影响相对较小。该研究结果可为双支腿CFB锅炉的燃烧调整提供指导。

  8. Some test results of Maritsa East lignite mine- first large-scale circulating fluidized bed combustion - as the basis of the restructuring process

    International Nuclear Information System (INIS)

    One of the consequences of energy sector restructuring in the transition countries is an increasing number of shareholders interested in profitable power plants. The traditional energy sector structural and operating paradigms evolved together, in symbiosis. power generation from coal is still negatively associated with severe pollutant emissions like NOx, SO2. In Bulgaria particularly power generation relies on the Maritsa-East coal mine as the single national energy source. The coal has an extremely poor quality (high sulphur, ash and water content) yielding high emissions of pollutants during combustion. The first large-scale test of circulating fluidized bed combustion (CFB) of Maritsa-East coal mine took place in 1998. For this purpose, test facilities in Austria Energy and Environment (AEE) and RWE's power plant Niederraussen were used. This analysis is very important for the management of National Energy Company as regards restructuring and privatisation. (author)

  9. 260t/h circulating fluidized bed boiler cleaning practices%260t/h循环流化床锅炉清洗实践

    Institute of Scientific and Technical Information of China (English)

    吴新汩; 杨次雄

    2012-01-01

    This paper circulating fluidized bed boiler(CFB) boiler water system new cleaning purposes,washing circuit set,get ready to work before cleaning,washing steps,the cleaning process of testing,cleaning quality assessment for a specific discussion.%本文对循环流化床锅炉(CFB)新建锅炉汽水系统的清洗目的、清洗回路的设置、清洗前得准备工作、清洗步骤、清洗过程的检测、清洗质量的评定进行了具体的论述。

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-03-31

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

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

    Directory of Open Access Journals (Sweden)

    Maximilian J. Hodapp

    2012-01-01

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

  12. Experimental Study on Gas-Solid Mass Transfer in Circulating Fluidized Beds%循环流化床气固传质实验研究

    Institute of Scientific and Technical Information of China (English)

    王琳娜; 张苓; 靳东杰; 李静海

    2002-01-01

    This study is devoted to gas-solid mass transfer behavior in heterogeneous two-phase flow. Experiments were carried out in a cold circulating fluidized bed of 3.0 m in height and 72 mm in diameter with naphthalene particles. Axial and radial distributions of sublimated naphthalene concentration in air were measured with an online concentration monitoring system HP GC-MS. Mass transfer coefficients were obtained under various operating conditions, showing that heterogeneous flow structure strongly influences the axial and radial profiles of mass transfer coefficients. In the bottom dense region, mass transfer rate is high due to intensive dynamic behavior and higher relative slip velocity between gas and clusters. In the middle transition region and the upper dilute region, as a result of low mass transfer driving force and the influence of flow structure, mass transfer rate distribution becomes non-uniform. In conclusion, among the operating parameters influencing mass transfer coefficients, the superficial gas velocity is the most important factor and the solid circulation rate should be also taken into account.

  13. Gas-solid flow field numerical simulation of different feeding and returning formations of flue-gas circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    WANG Hu

    2012-01-01

    3D Euler double-fluid model was applied and three different feedstocks and reverts formations were simulated.By calculating and analyzing the state of gas and solid fluxion in absorber using three different methods of the feedstocks and reverts in recirculating fluidized bed,described the behavior of gas and solid through the gas-phase velocity,turbulence intensity,gas-solid sliding velocity,and density of particles.The results show that the feedstocks and reverts enters into absorption tower through two symmetrical feedings and are mixed with flue gas.Based on the respective analysis of each model and the comparison analysis of the three models,this paper drew conclusions.The turbulence intensity of absorption tower is high,gas-solid sliding speed is big,and granule concentration near the axis is high,which has advantages for desulfurization and improving the utilization rate of absorbent.

  14. A Study of Solid Particles Feeding Tehnic by Fluidization Une technique d'alimentation en particules solides par fluidisation

    Directory of Open Access Journals (Sweden)

    Dolignier J.-C.

    2006-12-01

    Full Text Available The study of heterogeneous reactions in a drop tube furnace, at a laboratory scale, needs a continuous feeding and dispersing technic to yield mass flow rates as low as 1 g/h. In the present work, a solution based on fluidization, is proposed. A mixture of lime and sand is fluidized at a superficial velocity higher than the free fall velocity of the lime particles which are therefore carried over by the fluidizing gas stream out of the bed. The effects of various parameters such as the particles diameter, the lime content in the solid mixture, the height of the fluidized bed and the gas fluidizing velocity, on the flow have been investigated. The operating conditions leading to the obtention of a constant solid rate have been optimized. A simple method of evaluating the mass of the evacuated and dispersed lime particles have been developed, and satisfactory results were obtained. L'étude des réactions hétérogènes dans un four à chute à l'échelle du laboratoire nécessite l'utilisation d'une technique d'alimentation et de dispersion afin de débiter des masses de solides autour de 1 g/h. Dans ce présent travail, une technique basée sur la fluidisation est proposée. Un mélange de chaux et de sable est fluidisé à une vitesse superficielle plus élevée que la vitesse terminale de chute des particules de chaux, qui par conséquent sont transportées hors du lit. L'influence des divers paramètres tels que le diamètre des particules, le pourcentage de chaux dans le mélange, la hauteur du lit et la vitesse de fluidisation du gaz sur l'écoulement ont été étudiés. Les conditions opératoires permettant d'obtenir des débits de solides constants ont été optimisées. Une méthode relativement simple permettant d'évaluer la quantité de solide évacuée a été développée et des résultats satisfaisants ont été obtenus.

  15. Biodegradation of 2,4,6-trichlorophenol in a packed-bed biofilm reactor equipped with an internal net draft tube riser for aeration and liquid circulation

    International Nuclear Information System (INIS)

    For the aerobic biodegradation of the fungicide and defoliant 2,4,6-trichlorophenol (2,4,6-TCP), a bench-scale packed-bed bioreactor equipped with a net draft tube riser for liquid circulation and oxygenation (PB-ALR) was constructed. To obtain a high packed-bed volume relative to the whole bioreactor volume, a high AD/AR ratio was used. Reactor's downcomer was packed with a porous support of volcanic stone fragments. PB-ALR hydrodynamics and oxygen mass transfer behavior was evaluated and compared to the observed behavior of the unpacked reactor operating as an internal airlift reactor (ALR). Overall gas holdup values εG, and zonal oxygen mass transfer coefficients determined at various airflow rates in the PB-ALR, were higher than those obtained with the ALR. When comparing mixing time values obtained in both cases, a slight increment in mixing time was observed when reactor was operated as a PB-ALR. By using a mixed microbial community, the biofilm reactor was used to evaluate the aerobic biodegradation of 2,4,6-TCP. Three bacterial strains identified as Burkholderia sp., Burkholderia kururiensis and Stenotrophomonas sp. constituted the microbial consortium able to cometabolically degrade the 2,4,6-TCP, using phenol as primary substrate. This consortium removed 100% of phenol and near 99% of 2,4,6-TCP. Mineralization and dehalogenation of 2,4,6-TCP was evidenced by high COD removal efficiencies (∼95%), and by the stoichiometric release of chloride ions from the halogenated compound (∼80%). Finally, it was observed that the microbial consortium was also capable to metabolize 2,4,6-TCP without phenol as primary substrate, with high removal efficiencies (near 100% for 2,4,6-TCP, 92% for COD and 88% for chloride ions)

  16. Biodegradation of 2,4,6-trichlorophenol in a packed-bed biofilm reactor equipped with an internal net draft tube riser for aeration and liquid circulation

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-De Jesus, A.; Romano-Baez, F.J.; Leyva-Amezcua, L.; Juarez-Ramirez, C.; Ruiz-Ordaz, N. [Departamento de Ingenieria Bioquimica, Escuela Nacional de Ciencias Biologicas, IPN. Prol. Carpio y Plan de Ayala, Colonia Santo Tomas, s/n. CP 11340, Mexico, D.F. (Mexico); Galindez-Mayer, J. [Departamento de Ingenieria Bioquimica, Escuela Nacional de Ciencias Biologicas, IPN. Prol. Carpio y Plan de Ayala, Colonia Santo Tomas, s/n. CP 11340, Mexico, D.F. (Mexico)], E-mail: cmayer@encb.ipn.mx

    2009-01-30

    For the aerobic biodegradation of the fungicide and defoliant 2,4,6-trichlorophenol (2,4,6-TCP), a bench-scale packed-bed bioreactor equipped with a net draft tube riser for liquid circulation and oxygenation (PB-ALR) was constructed. To obtain a high packed-bed volume relative to the whole bioreactor volume, a high A{sub D}/A{sub R} ratio was used. Reactor's downcomer was packed with a porous support of volcanic stone fragments. PB-ALR hydrodynamics and oxygen mass transfer behavior was evaluated and compared to the observed behavior of the unpacked reactor operating as an internal airlift reactor (ALR). Overall gas holdup values {epsilon}{sub G}, and zonal oxygen mass transfer coefficients determined at various airflow rates in the PB-ALR, were higher than those obtained with the ALR. When comparing mixing time values obtained in both cases, a slight increment in mixing time was observed when reactor was operated as a PB-ALR. By using a mixed microbial community, the biofilm reactor was used to evaluate the aerobic biodegradation of 2,4,6-TCP. Three bacterial strains identified as Burkholderia sp., Burkholderia kururiensis and Stenotrophomonas sp. constituted the microbial consortium able to cometabolically degrade the 2,4,6-TCP, using phenol as primary substrate. This consortium removed 100% of phenol and near 99% of 2,4,6-TCP. Mineralization and dehalogenation of 2,4,6-TCP was evidenced by high COD removal efficiencies ({approx}95%), and by the stoichiometric release of chloride ions from the halogenated compound ({approx}80%). Finally, it was observed that the microbial consortium was also capable to metabolize 2,4,6-TCP without phenol as primary substrate, with high removal efficiencies (near 100% for 2,4,6-TCP, 92% for COD and 88% for chloride ions)

  17. Reprint of “Experiences in sulphur capture in a 30 MWth Circulating Fluidized Bed boiler under oxy-combustion conditions”

    International Nuclear Information System (INIS)

    CO2 and SO2 from fossil fuel combustion are contributors to greenhouse effect and acid rain respectively. Oxy-combustion technology produces a highly concentrated CO2 stream almost ready for capture. Circulating Fluidized Bed (CFB) boiler technology allows in-situ injection of calcium-based sorbents for efficient SO2 capture. CIUDEN's 30 MWth CFB boiler, supplied by Foster Wheeler and located at the Technology Development Centre for CO2 Capture and Transport (es.CO2) in Spain, is the first of its kind for executing test runs at large pilot scale under both air-combustion and oxy-combustion conditions. In this work, SO2 emissions under different scenarios have been evaluated. Variables such as limestone composition, Ca/S molar ratio and bed temperature among others have been considered along different test runs in both air-combustion and oxy-combustion conditions to analyse its influence on SO2 abatement. Fly and bottom ash, together with flue gas analysis have been carried-out. Desulphurization performance tests results are presented. - Highlights: • Sulphur capture efficiency (%) was higher in oxy-combustion compared to air-combustion in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. • For a Ca/S molar ratio higher than 2.6 there was barely any improvement on sulphur capture efficiency for both air-combustion and oxy-combustion conditions in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. • Optimum temperature for sulphur capture at a fixed Ca/S molar ratio is around 880–890 °C under oxy-combustion conditions and for anthracite coal with limestone as sorbent in a 30 MW thermal CFB boiler

  18. Development and Implementation of 3-D, High Speed Capacitance Tomography for Imaging Large-Scale, Cold-Flow Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Marashdeh, Qussai [Tech4imaging LLC, Columbus, OH (United States)

    2013-02-01

    A detailed understanding of multiphase flow behavior inside a Circulating Fluidized Bed (CFB) requires a 3-D technique capable of visualizing the flow field in real-time. Electrical Capacitance Volume Tomography (ECVT) is a newly developed technique that can provide such measurements. The attractiveness of the technique is in its low profile sensors, fast imaging speed and scalability to different section sizes, low operating cost, and safety. Moreover, the flexibility of ECVT sensors enable them to be designed around virtually any geometry, rendering them suitable to be used for measurement of solid flows in exit regions of the CFB. Tech4Imaging LLC has worked under contract with the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) to develop an ECVT system for cold flow visualization and install it on a 12 inch ID circulating fluidized bed. The objective of this project was to help advance multi-phase flow science through implementation of an ECVT system on a cold flow model at DOE NETL. This project has responded to multi-phase community and industry needs of developing a tool that can be used to develop flow models, validate computational fluid dynamics simulations, provide detailed real-time feedback of process variables, and provide a comprehensive understating of multi-phase flow behavior. In this project, a complete ECVT system was successfully developed after considering different potential electronics and sensor designs. The system was tested at various flow conditions and with different materials, yielding real-time images of flow interaction in a gas-solid flow system. The system was installed on a 12 inch ID CFB of the US Department of Energy, Morgantown Labs. Technical and economic assessment of Scale-up and Commercialization of ECVT was also conducted. Experiments conducted with larger sensors in conditions similar to industrial settings are very promising. ECVT has also the potential to be developed for imaging multi

  19. Circulating fluidized bed gasification of low rank coal: Influence of O2/C molar ratio on gasification performance and sulphur transformation

    Science.gov (United States)

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

    2016-08-01

    To promote the utilization efficiency of coal resources, and to assist with the control of sulphur during gasification and/or downstream processes, it is essential to gain basic knowledge of sulphur transformation associated with gasification performance. In this research we investigated the influence of O2/C molar ratio both on gasification performance and sulphur transformation of a low rank coal, and the sulphur transformation mechanism was also discussed. Experiments were performed in a circulating fluidized bed gasifier with O2/C molar ratio ranging from 0.39 to 0.78 mol/mol. The results showed that increasing the O2/C molar ratio from 0.39 to 0.78 mol/mol can increase carbon conversion from 57.65% to 91.92%, and increase sulphur release ratio from 29.66% to 63.11%. The increase of O2/C molar ratio favors the formation of H2S, and also favors the retained sulphur transforming to more stable forms. Due to the reducing conditions of coal gasification, H2S is the main form of the released sulphur, which could be formed by decomposition of pyrite and by secondary reactions. Bottom char shows lower sulphur content than fly ash, and mainly exist as sulphates. X-ray photoelectron spectroscopy (XPS) measurements also show that the intensity of pyrite declines and the intensity of sulphates increases for fly ash and bottom char, and the change is more obvious for bottom char. During CFB gasification process, bigger char particles circulate in the system and have longer residence time for further reaction, which favors the release of sulphur species and can enhance the retained sulphur transforming to more stable forms.

  20. SOLIDS CIRCULATION RATE OF ULTRA-FINE POWDERS IN SPOUTED BED WITH DRAFT TUBE%超细粉在导向管喷动床中的固体循环速率

    Institute of Scientific and Technical Information of China (English)

    周勇; 马兰; 石炎福

    2004-01-01

    Ultra-fine powders are difficult to be fluidized due to the strong particle to particle cohesiveness.However, the authors' experiments showed that the ultra-fine powder CaCO3 could be stably fluidized in a spouted bed with a draft tube. The effects of geometric and operating parameters on solid circulation rate of ultra-fine powder CaCO3 were investigated in a 120 mm diameter transparent semicircular spouted bed with a draft tube. Three draft tubes with different sizes were used in this study. It was found that the solids circulation rate was mainly dependent on the drawing rate of the gas jet from the nozzle, then on the gas transport capacity in the draft tube. With increasing gas feed rate, distance between the nozzle and the draft tube inlet and draft tube diameter, the solids circulation rate could be increased. Based on the jet theory, a quantitative correlation was proposed for predicting the solid circulation rate of ultra-fine powders in a spouted bed with a draft tube by taking into account the gas transport capacity in the draft tube.

  1. 75 t/h循环流化床锅炉改造%The Reform of A 75t/h Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    阴志青

    2013-01-01

    In the view of the abrasion of wind chamber and small bell cap, material returning device which is easy to bend and deform under the condition of high temperature, poor use reliability, the serious ash deposition, the reform of a 75t/h circulating fluidized bed boiler can bet⁃ter paly the role of energy-saving and power-saving, improve boiler efficiency, reduce boiler abrasion, improve the economy and stability of boiler.%  鉴于某75 t循环流化床锅炉的风室风帽磨损严重及返料装置高温状态下易发生弯曲变形、使用可靠性较差、尾部积灰严重等问题进行改造;更好地发挥循环流化床锅炉节能节电,提高锅炉的效率,减少锅炉的磨损,提高锅炉运行经济性与稳定性。

  2. Photocatalytic degradation of Bisphenol A (BPA) using immobilized TiO{sub 2} and UV illumination in a horizontal circulating bed photocatalytic reactor (HCBPR)

    Energy Technology Data Exchange (ETDEWEB)

    Wang Rongchang; Ren Dianjun [State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Aquatic Environment, Ministry of Education of China, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Xia Siqing, E-mail: wang_rc2003@yahoo.com.cn [State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Aquatic Environment, Ministry of Education of China, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Zhang Yalei; Zhao Jianfu [State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Aquatic Environment, Ministry of Education of China, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

    2009-09-30

    Photocatalytic degradation of Bisphenol A (BPA) in the presence of titanium dioxide (TiO{sub 2}) and ultraviolet (UV) illumination was performed in a self-designed horizontal circulating bed photocatalytic reactor (HCBPR). TiO{sub 2} catalyst was immobilized on the surface of polyurethane foam (PF) cubes via microwave-assisted liquid phase deposition. The effects of initial BPA concentration, initial pH, TiO{sub 2} dosage and temperature on BPA photodegradation were investigated in order to obtain the optimum operational conditions. The results reveal that the BPA degradation efficiency can be effectively improved by increasing pH from 3.4 to 12.3 or decreasing the initial BPA concentration from 50 to 10 ppm. The optimum TiO{sub 2} carrier dosage (the ratio of the volume of PF carriers to the effective reaction volume of HCBPR) was about 1%. Besides, the effect of temperature on BPA photodegradation was found to be unremarkable in the range of 21.2-30.5 deg. C. Total organic carbon (TOC) was used to evaluate the mineralization of BPA during the photodegradation process. Under the optimum conditions, 95% removal of TOC and 97% removal of BPA can be achieved after 6 h of UV radiation, which demonstrates the high photodegradation efficiency of BPA in HCBPR.

  3. Properties of circulating fluidized bed combustion ashes road base materials%固硫灰路面基层材料的性能

    Institute of Scientific and Technical Information of China (English)

    尹元坤; 卢忠远; 李军; 牛云辉

    2012-01-01

    Circulating fluidized bed combustion ashes (FBCF) were used as road base materials. The properties of original and pretreated FBCF road base materials were studied. And the influence of heavy metal of FBCF on the soil was also researched through leaching experiments. Results show that high volume stability, low inflation rates and the better road performance were obtained when pretreated FBCF was used. In addition, FBCF road base materials have lower heavy metal leaching rate, which in line with environmental protection require- ments.%以固硫灰作为路面基层材料,研究了固硫灰原灰和经预处理固硫灰路面基层材料的最佳含水量、最大干密度、体积安定性、膨胀率和强度等性能。同时,通过重金属浸出实验评估了固硫灰对土壤环境的影响。结果表明,经预处理固硫灰路面基层材料体积安定性好,膨胀率低,性能良好;此外,固硫灰重金属浸出率低,符合环保要求。

  4. Effect of SiO2/Na2O mole ratio on the properties of foam geopolymers fabricated from circulating fluidized bed fly ash

    Institute of Scientific and Technical Information of China (English)

    Ze Liu; Ning-ning Shao; Tian-yong Huang; Jun-feng Qin; Dong-min Wang; Yu Yang

    2014-01-01

    Geopolymers are three-dimensional aluminosilicates formed in a short time at low temperature by geopolymerization. In this pa-per, alkali-activated foam geopolymers were fabricated from circulating fluidized bed fly ash (CFA), and the effect of SiO2/Na2O mole ratio (0.91-1.68) on their properties was studied. Geopolymerization products were characterized by mechanical testing, scanning electron mi-croscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The results show that SiO2/Na2O mole ratio plays an important role in the mechanical and morphological characteristics of geopolymers. Foam samples prepared in 28 d with a SiO2/Na2O mole ratio of 1.42 exhibit the greatest compressive strength of 2.52 MPa. Morphological analysis reveals that these foam geo-polymers appear the relatively optimized pore structure and distribution, which are beneficial to the structure stability. Moreover, a combina-tion of the Si/Al atomic ratio ranging between 1.47 and 1.94 with the Na/Al atomic ratio of about 1 produces the samples with high strength.

  5. Finial Scientific/Technical Report: Application of a Circulating Fluidized Bed Process for the Chemical Looping Combustion of Solid Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Wei-Ping Pan; Dr. John T. Riley

    2005-10-10

    Chemical Looping Combustion is a novel combustion technology for the inherent separation of the greenhouse gas, CO{sub 2}. In 1983, Richter and Knoche proposed reversible combustion, which utilized both the oxidation and reduction of metal. Metal associated with its oxidized form as an oxygen carrier was circulated between two reactors--oxidizer and reducer. In the reducer, the solid oxygen carrier reacts with the fuel to produce CO{sub 2}, H{sub 2}O and elemental metal only. Pure CO{sub 2} will be obtained in the exit gas stream from the reducer after H{sub 2}O is condensed. The pure CO{sub 2} is ready for subsequent sequestration. In the oxidizer, the elemental metal reacts with air to form metal oxide and separate oxygen from nitrogen. Only nitrogen and some unused oxygen are emitted from the oxidizer. The advantage of CLC compared to normal combustion is that CO{sub 2} is not diluted with nitrogen but obtained in a relatively pure form without any energy needed for separation. In addition to the energy-free purification of CO{sub 2}, the CLC process also provides two other benefits. First, NO{sub x} formation can be largely eliminated. Secondly, the thermal efficiency of a CLC system is very high. Presently, the CLC process has only been used with natural gas. An oxygen carrier based on an energy balance analysis and thermodynamics analysis was selected. Copper (Cu) seems to be the best choice for the CLC system for solid fuels. From this project, the mechanisms of CuO reduction by solid fuels may be as follows: (1) If pyrolysis products of solid fuels are available, reduction of CuO could start at about 400 C or less. (2) If pyrolysis products of solid fuels are unavailable and the reduction temperature is lower, reduction of CuO could occur at an onset temperature of about 500 C, char gasification reactivity in CO{sub 2} was lower at lower temperatures. (3) If pyrolysis products of solid fuels are unavailable and the reduction temperature is higher than 750 C

  6. Lateral Solids Mixing in the Dense Zone of a Circulating Fluidized Bed%循环流化床密相区内颗粒的横向扩散的研究

    Institute of Scientific and Technical Information of China (English)

    杨海瑞; 吕俊复; 刘青; 岳光溪

    2002-01-01

    Lateral solid mixing was investigated experimentally in the dense zone of a 900mm×100mm×5.2m rectangular circulating fluidized bed riser. Using heated tracer injection, the lateral solid dispersion was determined by measuring the temperature response at different lateral positions. Furthermore, a one-dimensional dispersion model, which describes the solid mixing in the dense zone, is presented. The experimental results were used to determine the lateral particle dispersion coefficient under various operating conditions. A correlation of dispersion coefficient with bed height, gas velocity, and particle size is also proposed.

  7. Simulations of a Circulating Fluidized Bed Chemical Looping Combustion System Utilizing Gaseous Fuel Simulation de la combustion en boucle chimique d’une charge gazeuse dans un lit fluidisé circulant

    Directory of Open Access Journals (Sweden)

    Mahalatkar K.

    2011-05-01

    Full Text Available Numerical studies using Computational Fluid Dynamics (CFD have been carried out for a complete circulating fluidized bed chemical looping combustor described in the literature (Abad et al., 2006 Fuel 85, 1174-1185. There have been extensive experimental studies in Chemical Looping Combustion (CLC, however CFD simulations of this concept are quite limited. The CLC experiments that were simulated used methane as fuel. A 2-D continuum model was used to describe both the gas and solid phases. Detailed sub-models to account for fluid-particle and particleparticle interaction forces were included. Global models of fuel and carrier chemistry were utilized. The results obtained from CFD were compared with experimental outlet species concentrations, solid circulation rates, solid mass distribution in the reactors, and leakage and dilution rates. The transient CFD simulations provided a reasonable match with the reported experimental data. Des études numériques de simulation des écoulements (CFD ont été réalisées sur un lit fluidisé circulant opérant en combustion par boucle chimique (CLC décrit dans la littérature (Abad et al., 2006 Fuel 85, 1174-1185. Si de nombreuses études expérimentales ont été conduites pour étudier le procédé CLC, les études concernant la simulation des écoulements par CFD de ce concept sont très limitées. Le système de combustion en boucle chimique simulé dans cette étude concerne la combustion d’une charge gazeuse (méthane. Un modèle 2-D à deux phases continues a été utilisé pour décrire les phases gaz et solide avec des sous-modèles détaillés pour décrire les forces d’interactions entre fluideparticule et particule-particule. Des modèles cinétiques globaux ont été intégrés pour décrire les réactions de combustion et de transformation du matériau transporteur d’oxygène. Les résultats obtenus par CFD ont été comparés aux concentrations expérimentales mesurées des diff

  8. Circulating fluidized bed combustion fly ash based mineraladmixturesused in concrete%固硫灰作矿物掺和料制备混凝土研究

    Institute of Scientific and Technical Information of China (English)

    莫兆庭

    2015-01-01

    Circulating fluidized bed combustion (CFBC) fly ash was the waste that discharged by circulating fluidized bed boiler, which contained certain amount of chainotte minerals. The chemical compositions and physical properties of CFBC fly ashwere distinct with ordinary fly ash, which were suited to be used in construction materials.However, CFBC fly ash has its own special nature, such as self-hardening, pozzolanic activity and expansion characteristics, which restrict the utilization in building materials. In this paper,the physical and chemical properties of CFBC fly ash were characterized by SEM, particle size analysis,etc. And the activity index of CFBCand composite system contained CFBC fly ash, ordinary fly ash and slag were measured. The utilization of CFBC fly ash in concrete has also been discussed. Results showed that the activity index of CFBC fly ash increased with decreasing of the particle size of CFBC fly ash. The activity index would be decreased when ordinary fly ash and slag were mixed. The CFBC fly ash could be used to prepare concrete. And the properties of the prepared concrete would be improved with addition of CFBC fly ash in certain content range.%固硫灰是循环流化床烧煤技术所产生的废弃物,含有部分烧粘土质矿物,与普通粉煤灰相比其化学组成和性质有一定差异,经过一定加工和配料可以做建筑材料的原材料。但因为固硫灰有其自身特殊性质,如自硬性、火山灰活性和膨胀性等特点,因此在建筑材料领域应用受到一定限制。本文利用SEM微观分析、粒径分析等手段研究了固硫灰的物化特性,同时对固硫灰、粉煤灰、矿粉的活性指数进行分析,并将固硫灰作为矿物掺合料制备混凝土。实验结果表明:固硫灰活性随着粒径减小而增加,与粉煤灰和矿粉复掺会降低体系的活性指数;可以利用固硫灰做矿物掺合料制备混凝土,且其掺量在一定范围内对改善

  9. Gasification of secondary fuels in a circulating fluidized bed for energetic use in cement production; Vergasung von Sekundaerbrennstoffen in der zirkulierenden Wirbelschicht zur energetischen Nutzung fuer die Zementherstellung

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, J.; Gafron, B. [Lurgi Umwelt GmbH, Frankfurt am Main (Germany); Scur, P.; Wirthwein, R. [Ruedersdorfer Zement GmbH (Germany)

    1998-09-01

    Ruedersforf cement factory was commissioned a century ago as one of the first in Germany. After the plant was taken over by Readymix AG, a comprehensive sanitation concept was carried through. The plant has a production capacity of 8000 t/d of cement clinkers which are produced in a new kiln with a capacity of 6000 t/d and two modernized kilns each with a capacity of 1000 t/d. Reduction of energy consumption was the main goal of modernisation, with fuel gas generation in a circulating fluidized bed as a key element. The unit provides 40 % of the energy consumed by the clinker production process and is also used for selective ash production up to 25 t/h. The ash is used as a raw material for cement production. (orig./SR) [Deutsch] Bereits vor 100 Jahren wurde eine der ersten Zementfabriken in Deutschland am Standort Ruedersdorf in Betrieb genommen. Zum Erhalt der Wettbewerbsfaehigkeit wurde nach der Uebernahme des Werkes Ruedersdorf durch die Readymix AG ein umfangreiches Sanierungskonzept in die Wege geleitet. Bei einer Produktionskapazitaet von ca. 8 000 t Klinker pro Tag werden eine neue Ofenanlage mit einer Kapazitaet von 6 000 t/Tag sowie 2 sanierte kleine Anlagen zu je 1000 t/Tag betrieben. In der neuen Ofenanlage werden alle Moeglichkeiten genutzt, den Energiebedarf fuer die Klinkerproduktion zu senken. Eine wesentliche neue innovative Komponente ist dabei eine Brenngaserzeugung in einer Zirkulierenden Wirbelschicht, ueber die im folgenden berichtet werden soll. Die Anlage kann bis zu 40% des Energiebedarfes des Zementprozesses liefern. Weiterhin wird mit der ZWS eine gezielte Ascheproduktion, bis zu 25 t/h, betrieben. Diese Aschen sind Teil der Rohstoffrezeptur an der Rohmuehle. (orig./SR)

  10. Technical and economical optimization of wood gasification in a circulating fluidized bed. Final report; Technische und wirtschaftliche Optimierung der Vergasung von Holz in der zirkulierenden Wirbelschicht. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Ising, M.; Unger, C.; Heunemann, F.; Dinkelbach, L.

    2002-12-01

    The project's objective was the optimization of a novel process for high efficient combined heat and power production from solid biomass. The processed air blown wood gasification in a pilot scale circulating fluidized bed was added by a catalytic tar reformer which would yield a tar-free gas quality suitable for IC-engine operation. Major efforts were taken for technical improvement of the tar reformer, especially concerning temperature control and cleaning devices which is important for keeping constantly a high activity. Pure natural timber did not yield chemical deactivation at the catalyst whereas the gasification of waste wood yielded decreasing activity which could be partly reversed by special measures taken. Further optimization of the process considered a better automation and improvement of the engine's flue gas emissions. Also a detailed economic consideration and evaluation of the entire process has been carried out. As a result the novel process should have economic advantages compared with conventional technology. (orig.) [German] Gegenstand des Vorhabens war die Weiterentwicklung eines Verfahrens zur effizienteren Strom- und Waermegewinnung aus festen Biobrennstoffen. Durch luftgeblasene Vergasung von Holz im Pilotmassstab in einer zirkulierenden Wirbelschicht und anschliessender katalytischer Teerspaltung konnte ein niederkalorisches Brenngas erzeugt werden, welches zum Betrieb eines Motoren-Blockheizkraftwerks geeignet war. Im Rahmen der Verfahrensoptimierung wurde der katalytische Teer-Reformer, insbesondere in Bezug auf Temperaturfuehrung und die zum Aktivitaetserhalt wichtige Abreinigungsvorrichtung, verbessert. Bei der Vergasung von Naturholz wurde keine chemische Desaktivierung festgestellt. Beim Altholzeinsatz wurde ein ueberwiegend reversibler Aktivitaetsverlust verzeichnet und begruendet. Geeignete Gegenmassnahmen wurden untersucht und beschrieben. Weitere Optimierungen betrafen die Anlagensteuerungstechnik im Hinblick auf die

  11. Photocatalytic oxidation of Rhodamine B in a three-phase internal circulating fluidized bed with TiO2/SiO2 as photocatalyst

    Institute of Scientific and Technical Information of China (English)

    YOU Hong; SUN Li-xin; LUO Wei-nan; LIU Ting

    2010-01-01

    A novel photoreactor of three-phase internal circulating fluidized bed was applied to the degradation of Rhodamine B with TiO/SiO2 catalyst and TiO2 powder,respectively.The experimental results showed that the photocatalytic activity of TiO2/SiO2 catalyst was much higher than that of TiO2 powder under the same condition,and the half life of Rhodamine B using TiO2/SiO2 was 9.5 min,much lower than 63 min when using TiO2 powder.Moreover,TiO2/SiO2 had a good adsorption capacity of Rhodamine B,which played an important role on degradation.In addition,it was found that the degradation kinetics of Rodamine B with TiO2/SiO2 catalyst did not follow the first order reaction.The degradation kinetics model in terms of the adsorption process of catalyst and the analytic solution of reactant degradation rate in liquid phase could be deduced,which consisted of two parts.The first part was due to the adsorption,while the second part was due to the photocatalysis.In the beginning of the reaction,the adsorption process was dominant.However,when the adsorption achieved a balance,the degradation of Rhodamine B in liquid phase and solid phase was mainly caused by photocatalysis and the degradation kinetics model conformed to the first order reaction.

  12. Co-gasification of biomass and coal in a pressurised fluidised bed gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Andries, L.; Hein, K.R.G. [Lab. for Thermal Power Engineering, Dept. of Mechanical Engineering and Marine Technology, Delft Univ. of Technology (Netherlands)

    1996-12-31

    The Laboratory for Thermal Power Engineering of the Delft University of Technology is participating in an EU funded, international, R + D project which is designed to aid European industry in addressing issues regarding co-utilisation of biomass and/or waste in advanced coal conversion processes. The project comprises three main programmes, each of which includes a number of smaller subprogrammes. The three main programmes are: Coal-biomass systems component development and design; Coal-biomass environmental studies; Techno-economic assessment studies. (orig)

  13. Comparative evaluation of SRF and RDF co-combustion with coal in a fluidised bed combustor

    OpenAIRE

    Garg, A; Smith, Richard; Longhurst, Philip J.; Pollard, Simon J. T.; Simms, Nigel J; D. Hill

    2007-01-01

    The experimental study reported here was carried out to assess the feasibility of municipal solid waste (MSW) derived solid recovered fuel (SRF) in energy recovery applications. SRF was prepared by grinding and blending the major MSW constituents such as paper, plastics, wood and textile. The percentage of various constituents was the same as from the Ecodeco process employing bio- drying followed by mechanical treatment. The heating value of synthetic SRF was ca. 21 MJ/kg (...

  14. The fluid dynamics of a downer fluidised bed using a cluster-based approach (CBA

    Directory of Open Access Journals (Sweden)

    Germán González Silva

    2010-05-01

    Full Text Available The fluid dynamics of a downer reactor were numerically resolved by adapting a mathematical conservation model. The mathematical model was based on the solid and fluid properties and physical characteristics using a cluster-based approach (CBA. Comparing the numerical results to the experimental data found in the literature indicated that the mathematical model could satisfactorily predict the experimental data. The mathematical simulation determined that there were three fluid dynamic areas in the downer reactor which were characterized by accelerated, slowed-down and fully-developed flow. The fully developed flow area in the downer decreased with increased gas surface speed keeping solid flux constant.

  15. Utilization of post-reclamation dusts by combustion and oxidising in a pulsating, fluidised bed

    Directory of Open Access Journals (Sweden)

    J. Dańko

    2008-03-01

    Full Text Available Invcaigations of thc urilization process of durn. originated from thc mcchanical scclamatbn of uscd moulding sands with Furfury1 alcohol.werc pcrformcd. Colnbustion and oxidat ion processes of pulvcriscd and scparatetl in cycloncs binding agcnts and othcr organiccomponents wcrc carricd out in thc thcrmal mlairncr wherc a grain hcd ~mdcnvent pulsating fluidisat ion cithcs by thc atmnsphcric air orhy oxypcn cnriched air. Factors dclcrmining an effective pcrlormancc of dusls utilization by oxidising in rhc oxygcn cncichcd air wcreindicated and thc plan for thc Furthcr rcscwch was outlined.

  16. Utilization of post-reclamation dusts by combustion and oxidising in a pulsating, fluidised bed

    OpenAIRE

    Dańko, J.; Holtzer, M.; Dańko, R.

    2008-01-01

    Invcaigations of thc urilization process of durn. originated from thc mcchanical scclamatbn of uscd moulding sands with Furfury1 alcohol.werc pcrformcd. Colnbustion and oxidat ion processes of pulvcriscd and scparatetl in cycloncs binding agcnts and othcr organiccomponents wcrc carricd out in thc thcrmal mlairncr wherc a grain hcd ~mdcnvent pulsating fluidisat ion cithcs by thc atmnsphcric air orhy oxypcn cnriched air. Factors dclcrmining an effective pcrlormancc of dusls utilization by oxidi...

  17. Developments in the fluidised bed process for fibre recovery from thermoset composites

    OpenAIRE

    Pickering, S. J.; Turner, T.A.; Meng, F.(University of Notre Dame, Notre Dame, USA); Morris, C N; Heil, J.P.; K. H. Wong; Melendi-Espina, Sonia

    2015-01-01

    Carbon fibre reinforced plastic (CFRP) is being used in increasing quantities particularly in the transport industry to reduce carbon emissions through weight reduction and in the energy industries for renewable technologies, such as wind turbines. As a high value and energy intensive material to manufacture a good case can be made for recovering and reusing carbon fibre from waste material. A number of companies in Europe and the USA are now in the early stages of commercial operation, but t...

  18. Mathematical Determination of Thermal Load for Fluidised Bed Furnaces Using Sawdust

    Directory of Open Access Journals (Sweden)

    Antonescu Nicolae

    2014-06-01

    Full Text Available For technical applications, a physical model capable of predicting the particle evolution in the burning process along its trajectory through the furnace is very useful. There are two major demands: all the thermo-dynamic processes that describe the particle burning process must be accounted and the model must be written in such equation terms to allow the intervention for parameter settings and particle definition. The computations were performed for the following parameters: furnace average temperature between 700 and 1200 °C, size of the sawdust particle from 4 to 6 mm and fix carbon ignition between 500 and 900 °C. The values obtained for the characteristic parameters of the burning process ranged from 30 to 60 [kg/(h·m3] for the gravimetrical burning speed WGh and from 150 to 280 [kW/m3] for the volumetric thermal load of the furnace QV. The main conclusion was that the calculus results are in good agreement with the experimental data from the pilot installations and the real-case measurements in the sawdust working boiler furnaces or pre-burning chambers. Another very important conclusion is that the process speed variation, when the furnace temperature changes, confirms the thermo-kinetic predictions, namely that the burning process speed decreases when the furnace temperature increases.

  19. Nitrogen compounds in pressurised fluidised bed gasification of biomass and fossil fuels

    NARCIS (Netherlands)

    De Jong, W.

    2005-01-01

    Fossil fuels still dominate the energy supply in modern societies. The resources, however, are depleting. Therefore, other energy sources are to be exploited further within this century. Biomass is one of the practically CO2 neutral, renewable contributors to the future energy production. Nowadays m

  20. PlanHab: the combined and separate effects of 16 days of bed rest and normobaric hypoxic confinement on circulating lipids and indices of insulin sensitivity in healthy men.

    Science.gov (United States)

    Simpson, Elizabeth J; Debevec, Tadej; Eiken, Ola; Mekjavic, Igor; Macdonald, Ian A

    2016-04-15

    PlanHab is a planetary habitat simulation study. The atmosphere within future space habitats is anticipated to have reduced Po2, but information is scarce as to how physiological systems may respond to combined exposure to moderate hypoxia and reduced gravity. This study investigated, using a randomized-crossover design, how insulin sensitivity, glucose tolerance, and circulating lipids were affected by 16 days of horizontal bed rest in normobaric normoxia [NBR: FiO2 = 0.209; PiO2 = 133.1 (0.3) mmHg], horizontal bed rest in normobaric hypoxia [HBR: FiO2 = 0.141 (0.004); PiO2 = 90.0 (0.4) mmHg], and confinement in normobaric hypoxia combined with daily moderate intensity exercise (HAMB). A mixed-meal tolerance test, with arterialized-venous blood sampling, was performed in 11 healthy, nonobese men (25-45 yr) before (V1) and on the morning ofday 17of each intervention (V2). Postprandial glucose and c-peptide response were increased at V2 of both bed rest interventions (PHypoxia did not alter the adverse effects of bed rest on insulin sensitivity and glucose tolerance but appeared to increase insulin clearance. The negative effect of bed rest on HDL was compounded in hypoxia, which may have implications for long-term health of those living in future space habitats. PMID:26769956

  1. Study on mercury migration in a circulating fluidized bed combustion boiler%循环流化床燃煤锅炉中的汞迁移研究

    Institute of Scientific and Technical Information of China (English)

    武成利; 曹晏; 李寒旭; 潘伟平

    2012-01-01

    采用美国环保署颁布的吸附剂吸附汞采样方法30B(USEPA 40 CFR Part 60 30B)采集燃煤烟气中汞.选择一循环流化床燃煤机组进行现场采样,吸附剂吸附烟囱处烟气中的汞、入炉煤样、锅炉底灰、静电除尘器飞灰等样品同时采集.对该机组中汞质量平衡率进行衡算,通过汞质量平衡率说明了汞采样方法的准确性和有效性.评价了汞在飞灰、底灰和烟气中的分布,循环流化床锅炉底灰中对脱汞的贡献率仅0.55%,飞灰脱除汞的效率高达83.37%,剩余的16.08%的汞排放入大气环境,表明循环流化床机组是有效控制汞的清洁煤燃烧技术.%Mercury concentrations in the flue gas at the stack were measured using a sorbent trap method as per United States Environmental Protection Agency Method 30B (I. E. , USEPA 40 CFR Part 60 30B), and the sampling method has merits of convenient setup, simply operation and fast analysis. Field tests were conducted at a unit of the Circulating Fluidized Bed Combustion (CFBC). During the course of sampling the mercury in the flue gas, coal samples, bottom ash and fly ash were collected and analyzed. Rates of mercury material balance though the unit were calculated, and correctness and validity of mercury sampling method were certified. Mercury distributions in fly ash, bottom ash and flue gas were evaluated, and the results showed that firstly bottom ash of CFBC removed only 0. 55% of total mercury, secondly removal efficiency of fly ash reaching 83. 37% , in the end 16.08% of total mercury was emitted to the air. The determined data of mercury emissions show that the CFBC is a clean coal combustion technology of effectively removing mercury.

  2. Modeling of clusters characteristics in circulating fluidized beds%循环流化床中颗粒聚团特性的模拟

    Institute of Scientific and Technical Information of China (English)

    王帅; 刘国栋; 赵飞翔; 张清红; 陆慧林

    2014-01-01

    Considering the multi-scale structure of the dense phase in the form of clusters and the dilute phase in the form of dispersed particles in the circulating fluidized bed, the relationship between accelerations and local structure parameters in the dense phase and dilute phase was established and the stability condition of the minimum energy dissipation by multi-scale drag force was proposed. Based on the bivariate extreme value theory, a cluster structure dependent (CSD) drag coefficient model was developed. Gas-solids flow behavior and cluster characteristics in risers were simulated using a two-fluid model. The concentrations of particles obtained by the CSD model showed better agreement with experimental results. Cluster diameter increased, reached a maximum and fell down to single particle diameter with increasing solids concentrations. In the simulation, the influence of accelerations of gas and particles could not be ignored because it appeared to be on the same order of magnitude as acceleration of gravity.%考虑到循环流化床中分散颗粒和颗粒聚团同时存在的多尺度结构,确定了密相和稀相加速度与计算网格局部参数之间的关系,建立了多尺度曳力消耗能量最小的稳定性条件,基于双变量极值理论,构建了考虑颗粒团聚效应的多尺度气固相间曳力模型。结合双流体模型,对循环流化床内气固流动特性以及颗粒聚团特性进行了模拟研究。通过与实验值比较,考虑颗粒聚团影响的计算模型可以更好地贴近实验结果,颗粒聚团直径随颗粒浓度增大呈现先增大后减小的分布趋势,气体和颗粒的加速度在模拟中与重力加速度同处一个数量级,求解过程中不能被忽略。

  3. Analysis of the Causes of Circulating Fluidized Bed Boiler Water Wall Leakage%循环流化床锅炉水冷壁泄漏分析

    Institute of Scientific and Technical Information of China (English)

    徐伟; 李武荣

    2015-01-01

    This article describes a leakage of the circulating fluidized bed boiler water wall that appeared for the first time in the refinery .Through ultrasound scans, water cooling wall tube bundle remote field eddy current and wall thickness testing, to find all the defects of water wall tubes. At the same time, the damaged pipe is cut and analyzed by means of chemical composition analysis, mechanical performance analysis, pipeline anatomical analysis, corrosion products analysis, metallographic analysis, energy spectrum analysis and investigation of water quality. According to the results of the analysis and comparison of various typical characteristics of heating surface of boiler corrosion, it is found that the main causes of water wall leakage of boiler is low water quality qualified rate and the water cooled wall soda evaporation caused in the water cooled wall furnace alkalinity of local high and the occurrence of alkali corrosion resistance, eventually leading to water wall tube thinning intensity decreased leakage. Subsequent to take water wall damaged parts of the local replacement, water wall chemical cleaning measures to remedy, and strengthen the boiler water quality management for the prevention, the overall operation of the boiler starts again get a improvement.%本文针对炼厂内循环流化床锅炉首次出现的水冷壁泄漏,通过对水冷壁管束进行超声波扫描、远场涡流和壁厚检测,找到水冷壁管的缺陷部位。同时对受损管段割管进行化学成分分析、力学性能分析、管道解剖分析、腐蚀产物分析、金相分析、能谱分析以及水质调查,找出造成水冷壁泄漏的主要原因是锅炉水质合格率偏低以及水冷壁管中的汽水蒸发浓缩造成炉水碱度局部过高而引发碱腐蚀,最终导致水冷壁管减薄,强度不足发生泄漏。后续采取水冷壁受损部位局部更换、水冷壁化学清洗措施进行处理,同时加强锅炉水质管理进行

  4. EXPERIMENTAL STUDY ON COAL GASIFICATION IN A CIRCULATING FLUIDIZED BED%循环流化床煤气化试验研究

    Institute of Scientific and Technical Information of China (English)

    张荣光; 那永洁; 吕清刚

    2005-01-01

    Experiment results on gasification of a bituminous coal in a pilot scale circulating fluidized bed at atmospheric pressure and different operation conditions, rates of coal feed from 5.4 to 8.14kg/h, ratios of steam/coal from 0.19 to 0.7kg/kg and ratios of air/coal from 2.8 to 3.67kg/kg,are reported. The effect of operation conditions on gas compositions, calorific values, carbon conversions and gasification efficiencies are analyzed. At present stage, the maximum calorific value of product gas was 3.84MJ/Nm3 and the highest coal conversion efficiency was 73.7%. Much carbon was lost in fly ash after the cyclone due to the short of the lift, the low gasification temperatures and the low separation efficiency of the cyclone for fine particles.Gasification temperature must be limited to 930℃ for Shenhua coal to avoid slagging.%在常压循环流化床中试装置上进行了神华煤的气化试验,试验条件:加煤速率5.4~8.14kg/h、蒸汽煤比0.19~0.7kg/kg、空气煤比2.8~3.67kg/kg,分析了试验条件对煤气组成、热值、碳转化率和煤气效率的影响.在该试验阶段获得的煤气的最高热值为3.84MJ/Nm3,最高碳转化率为73.6%.由于提升管的高度很小、气化温度较低以及旋风炉对细颗粒分离效率不高,导致损失于飞灰中碳较多.试验结果表明对神华煤而言,气化温度应低于930℃以避免结渣.

  5. 低固含率气-液-固循环流化床流动特性%Hydrodynamics in gas-liquid-solids circulating fluidized beds with low solids holdups

    Institute of Scientific and Technical Information of China (English)

    刘建华; 刘明言; 胡宗定

    2013-01-01

    Hydrodynamics in gas-liquid-solids circulating fluidized beds with low solids holdups of resin particles was experimentally investigated with a high-speed image measurement and treatment technique of complementary metal oxide semiconductor. Influences of superficial liquid velocity, particle diameter and density, liquid surface tension and viscosity on the phase holdups, average gas bubble diameter, circulating rate of solids particles both in the riser and in the downer and bubble motions were investigated. Experimental data with reasonable physical explanations of the hydrodynamics of gas-liquid-solids circulating fluidized beds were obtained.%应用基于互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)传感器的高速图像采集和处理技术,实验研究了低固含率条件下,低密度大孔吸附树脂固体颗粒气-液-固三相循环流化床的流体力学行为,分析了操作条件、液相物性、颗粒性质等对床内的固体颗粒循环速率、相含率、气泡运动等特性的影响,得到了具有合理物理解释的实验数据和结果.

  6. Research of Nitrous Oxide Emission Characteristics on Lignite Circulating Fluidized Bed%大型褐煤循环流化床锅炉氧化亚氮排放特性

    Institute of Scientific and Technical Information of China (English)

    邱亚林

    2014-01-01

    The research of nitrous oxide emission characteristics on lignite circulating fluidized bed was carried out,the Various pa-rameters effect about the nitrous oxide emissions was studied� Thus the way of reduce nitrous oxide emission concentration was sought.%针对褐煤循环流化床开展氧化亚氮排放特性的研究,掌握不同参数对氧化亚氮排放的影响,从而提出降低氧化亚氮排放浓度的方法。

  7. Review of Study on Character and Development of Spouted Circulating Fluidized Bed Equipments for Biomass Fast Pyrolysis%喷动循环流化床生物质快速热解设备的特性分析与发展研究综述

    Institute of Scientific and Technical Information of China (English)

    任学勇; 常建民; 王鹏起; 苟进胜; 张立塔; 佟立成

    2009-01-01

    Present situations of domestic and foreign researches on biomass fast pyrolysis devices are summarized.Detailed accounts on spouted bed and circulating fluidized bed are stated and more in-depth analysis on spouted circulating fluidized bed is given.The orientation of research on spouted circulating fluidized bed fast pyrolysis devices is explored.%简要综述了生物质快速热解设备研究的国内外现状,继而详述了喷动床和循环流化床,重点对喷动循环流化床作了较深入的探析,探讨了喷动循环流化床快速热解设备研究的发展方向.

  8. Exergy efficiency analysis on large-scale circulating fluidized bed boilers%大型循环流化床锅炉火用效率分析

    Institute of Scientific and Technical Information of China (English)

    刘彦鹏; 钟北京; 李少华

    2015-01-01

    On the basis of boiler exergy balance mathematical model,the exergy efficiency and each exergy loss of large-scale circulating fluidized bed (CFB)boilers was analyzed.The results show that,the total ex-ergy loss of combustion and heat transfer of the CFB boiler was over 45% of the fuel chemical exergy, which is the main exergy loss of the CFB boiler.Increasing the power unit capacity and steam parameters can increase the average heat absorption temperature of the water in furnace,thus to reduce the heat trans-fer exergy loss of the boiler effectively.The exhaust exergy loss rate was about 1%,which is greatly smal-ler than that of the exhaust heat loss rate,but there's still potential to be tapped.For CFB boilers,the exer-gy loss rate during combustible gas incomplete combustion and heat transfer can be ignored.The unburned carbon exergy loss,which is the chemical exergy of the unburned carbon,should be paid more attention to be reduced due to its high quality.The CFB boiler slag has a high proportion of coal ash,so reducing the slag physical exergy loss has great significance to improving the CFB boiler efficiency.%采用锅炉火用平衡数学模型,对大型循环流化床(CFB)锅炉的各项火用损失和火用效率进行了分析,并以某亚临界300 MW机组CFB锅炉为对象,进行了实例计算,并对不同参数等级CFB锅炉进行了火用效率分析。结果表明:CFB锅炉的燃烧和传热火用损失之和占燃料化学火用的45%以上,是锅炉的主要火用损失;提高机组容量和蒸汽参数,可以提高炉水平吸热温度,从而有效降低锅炉传热火用损失;锅炉排烟火用损失率在1%左右,比排烟热损失率小很多;CFB锅炉的可燃气体未完全燃烧火用损失率、散热火用损失率均可忽略不计;固体未完全燃烧火用损失由于损失的是未燃尽碳的化学火用,其热能品位较高,因此应重点采取措施减小该项损失;CFB锅炉炉渣占煤

  9. Technology approach to improve the amount of steam of circulating fluidized bed boiler%提高循环流化床锅炉产汽量的技术途径

    Institute of Scientific and Technical Information of China (English)

    赵代林

    2015-01-01

    循环流化床炉属于新型节能先进锅炉,我厂于1996年和2003年安装两台35t/h的循环流化床锅炉,经过几年的运行,锅炉产汽量逐渐降低,特别是煤源发生变化后,锅炉产汽量由25t/h左右降至不足15t/h。本文针对锅炉产汽量低的原因,进行了系统的研究探讨,提出了合理建议,并进行技术改造,应用于生产实际中。%Circulating fluidized bed boiler is a kind of new energy-saving boiler. There were two circulating fluidized bed boiler in our plant. After running for several years,the amount of steam deceased gradually. Especially,the amount of steam was not less than 15t/h from 25 t/h after the change of coal. Combining with this problems,the reasons were diccussed and the suggestions were put forward. The revamping measures were carried on.

  10. Experimental study of spiral flow generator in liquid-solid horizontal circulating fluidized bed%水平液固循环流化床起旋器的实验研究

    Institute of Scientific and Technical Information of China (English)

    彭培英; 张伟; 刘燕

    2009-01-01

    An experiment was made of the particles distribution of each section of a single-loop solids circulation system in a φ29 mm×4 200 mm cold liquid-solid horizontal circulating fluidized bed test facility. The CCD image measurement and data processing system was used to study the particles distribution at different operating conditions with the spiral flow generator added.The experiment shows that the spiral pipe flow generator arranged in the liquid-solid horizontal circulating fluidized bed can effectively improve the uniform distribution of particles in a certain distance; but as the axial distance increases, the effect of the spiral flow generator weakened. There was a low non-uniform distribution as the guide vane angle and liquid flow rate increased. For the particle with the same diameter, density and initial volume add the larger the solid particles containing the greater rate of non-uniform degrees.%在φ29 mm×4 200 mm流化床装置上,利用CCD图像测量与数据处理系统在线对导流叶片式局部起旋器对水平液固循环流化床内固相颗粒分布特性的影响进行了研究.结果表明:安装局部起旋器后,颗粒分布状况在一定距离内得到明显改善;但随着轴向距离增加,起旋器作用效果减弱.随着导叶包角、液体流速的增加,颗粒固含率不均匀度减小.对于相同直径的颗粒,密度和初始加入量越大,颗粒固含率不均匀度越大.

  11. EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

    Science.gov (United States)

    The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

  12. 增压导向式喷动流化床固体颗粒循环速率的关联%Solid Circulating Rate in a Spouted-fluidized Bed with Draft Tube at Elevated Pressure

    Institute of Scientific and Technical Information of China (English)

    刘向东; 章名耀

    2001-01-01

    The effects of operating factors, such as spouting velocity, fluidizing velocity, pressure and particle size on solid circulating rate in a spouted-fluidized bed with draft tube were investigated. The experimental results showed that the spouting velocity was the most important factor. The solid circulating rate increased with increasing fluidizing velocity and pressure, and decreased with increasing mean particle diameter. Based on the experimental results, an empirical correlation of the solid circulating rate was established. This work is helpful to designing the carbide furnace in the second generation PFBC-CC system.%实验考察了喷动气速度、流化气速度、压力以及颗粒尺寸对增压导向式喷动流化床固体颗粒循环速率的影响规律,并归纳出关联式,为正在开发的第二代增压流化床联合循环发电系统(2GPFBC-CC)中关键部件-炭化炉的放大设计提供了帮助.

  13. Commissioning and Analysis of Integrative Sewage Sludge Incineration Demonstration Project with Circulating Fluidized Bed%循环流化床一体化污泥焚烧工程的调试及分析

    Institute of Scientific and Technical Information of China (English)

    吕清刚; 朱建国; 李诗媛; 李云玉; 那永洁; 包绍麟; 丁艳辉; 黄毅

    2012-01-01

    To investigate the feasibility of using incineration technology to treat excess sludge from WWTP, a sewage sludge incineration demonstration project with capacity of 100 t/d in Qige Sewage Treatment Plant of Hangzhou City was constructed, and the cold and hot commissionings were conducted. The 'old commissioning results showed that the monitoring data of key equipments, such as screw convey-incinerator and complex fluidized bed dryer, agreed well with the design values. The hot commissioning rerults indicated that the temperature was uniform in the complex fluidized bed dryer where the sewage sludge with 79% to 80% moisture content could be well dried and crushed, and the maximal diameter of dried sludge particles was 3 mm with the 50% cut size of 0. 32 mm. The dried sludge was immediately transported into the circulating fluidized bed incinerator with the incineration temperature of 860 t.It is concluded that the technology for integrative drying and incineration of sewage sludge in circulating fluidized bed an be applied in engineering projects.%为探索采用焚烧工艺处理污水厂剩余污泥的可行性,在杭州市七格污水处理厂建设了规模为100 t/d的污泥焚烧处理示范工程,并进行了冷、热态调试.冷态调试结果表明,系统关键设备如干污泥螺旋输送机、焚烧炉、复合干化器等的测试数据与设计值吻合.热态调试结果显示,复合干化器内温度均匀,含水率为79%~80%的湿污泥在复合干化器内破碎和干燥程度良好,干污泥颗粒最大直径为3 mm,50%的切割粒径为0.32 mm.干污泥即时进入循环流化床焚烧炉焚烧,焚烧温度为860℃.可见,采用循环流化床一体化焚烧技术处理污泥在工程上是可行的.

  14. 落叶松树皮喷动循环流化床快速热解的影响因素%Influence Factors of Larch Bark Fast Pyrolysis in Spouting-Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    王鹏起; 常建民; 杜洪双; 李瑞; 何明明; 张立塔

    2009-01-01

    对喷动循环流化床落叶松树皮快速热解过程中反应温度、物料粒径、进料速率及气体流量对热解产物产率的影响以及这4个因素共同作用对生物油产率的影响进行研究.结果表明:反应温度是影响热解产物产率的主要因素,气体流量影响较显著,在试验范围内物料粒径、进料速率影响不显著;喷动循环流化床最佳制备液体产物--生物油快速热解工艺条件为:反应温度550℃,物料粒径0.2~0.3 mm,进料速率20r·min~(-1),气体流量25m~3·h~(-1).%An experimental studied on the influence of larch bark fast pyrolysis in spouting-circulating fluidized bed products yield, in the pyrolysis process of reaction temperature, gas flow, particle size and feed rate, and the effects of the four factors in the interaction of bio-oil yield. The results show that: reaction temperature is the main factor that influences of pyrolysis yield of products, gas flow shows obvious influence, particle size and feed rate have no significant influence; spouting-circulating fluidized bed pyrolysis optimum conditions: reaction temperature 550℃ .particle size 0.2 ~ 0.3 mm,feed rate 20rmin-1,gas flow 25 m~3·h~-1).

  15. Ash related bed agglomeration during fluidized bed combustion, further development of the classification method based on CCSEM; CCSEM-luokitusmenetelmaen jatkokehittaeminen tuhkan aiheuttaman agglomeroitumisen tutkimisessa leiju- ja kiertopetipoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Laitinen, R.; Patrikainen, T.; Heikkinen, R.; Tiainen, M.; Virtanen, M. [Oulu Univ. (Finland). Inst. of Chemistry

    1997-10-01

    The scope of this project is to use the information and experience gained from the development of classification method to predict ash related problems like bed agglomeration during fluidised combustion. If boilers have to be shut down due to slagging or agglomeration of the bed material may cause significant economic losses for the entire energy production chain. Mineral classification methods based on the scanning electron microscopy are commonly used for coal ash investigation. In this work different biomass, peat, and peat-wood ash, fluidised-bed materials, and bed agglomerates were analysed with SEM-EDS combined with automatic image analysis software. The properties of ash particles are different depending on the fuel type. If biomass like wood or bark are added to peat the resulting ash has different properties. Due to the low mineral content in the original peat and to the fact that the majority of inorganic material is bound to the organic matrix, the classification has turned out to be less informative than was hoped. However, good results are obtained the by use of quasiternary diagrams. With these diagrams the distribution of particle composition is easily illustrated and thus meaningful prediction can be made of the slagging and agglomerating properties of ash. The content of ten different elements are determined for each particle by SEM-EDS combined with Link AIA software. The composition of the diagram corners can be varied Freely within these ten elements. (orig.)

  16. Equilibrium and kinetic studies of sorption of 2.4-dichlorophenol onto 2 mixtures: bamboo biochar plus calcium sulphate (BC and hydroxyapatite plus bamboo biochar plus calcium sulphate (HBC, in a fluidized bed circulation column

    Directory of Open Access Journals (Sweden)

    Alamin Ahmed Hassan

    2016-06-01

    Full Text Available Sorption studies were carried out to investigate removal of 2.4-dichlorophenol (2.4-DCP from aqueous solution in a fluidized bed by two types of adsorbent mixtures: BC (Bamboo char plus Calcium sulphate, and HBC (Hydroxyapatite plus Bamboo char plus Calcium sulphate; both manufactured in ball shape. The main material bamboo char was characterized by FTIR, DTA and SEM. The adsorption experiments were conducted in a fluidized bed circulation column. Adsorption, isotherms and kinetic studies were established under 180 min operating process time, at different initial 2.4-DCP solution concentrations ranging from 5–10 mg/L, and at different flow rates ranging from 0.25–0.75 L/min. The data obtained fitted well for both the Langmuir and Freundlich isotherm models; indicating favorable condition of monolayer adsorption. The kinetics of both adsorbents complies with the pseudo second-order kinetic model. BC was proven a new effective composite and low cost adsorbent which can be applied in the field of wastewater treatment, and it can also play an important role in industry water treatment.

  17. 飞灰流化床燃烧脱碳的试验研究%Experimental Study of Fly Ash Decarbonization on a Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    梅琳; 卢啸风; 王泉海; 潘智; 杨宇; 洪勇; 方纯全; 郭宏; 阳向东

    2014-01-01

    飞灰回燃脱碳效率较低,导致回燃后飞灰仍不能满足综合利用的要求。文中基于飞灰的冷态流化特性,在自行设计的纯然飞灰的热态试验台上进行了燃烧脱碳试验。试验结果表明:CFB 飞灰能够在流化床内连续稳定燃烧,维持炉内燃烧的最小截面热负荷约为0.4MW/m2,对应的临界飞灰含碳量为18%。密相区温度和运行床压对飞灰脱碳均有一定的影响。飞灰燃烧后在底渣的增重份额很小,最大不超过15%。试验系统的最大脱碳效率约为75%,远远高于飞灰回燃的脱碳效率。%ABSTRACT:Because of the huge difference between original boiler operating conditions and fly ash ideal combustion state, the decarbonization effect is disappointed. Consequently, fly ash decarbonization experiments were carried out on a lab-scale CFB combustor designed base on fluidization properties of fly ash and the decarbonization characteristics were presented. Results show that fly ash requires a minimum sectional thermal load of 0.4MW/m2 for continuous and stable combustion in test combustor, the corresponding critical carbon content in the fly ash is 18%. The carbon content in the fly ash is clearly affected by the dense-bed temperature and bed pressure drop during the combustion process. In addition, the fly ash mass fraction in bottom ash does not exceed 15%. The maximum decarbonization efficiency of the test CFB combustor is approximately 75%, which is much higher than that of FARC.

  18. 市政污泥热电厂循环流化床协同焚烧技术验证研究%Validation of municipal sludge incineration in circulation fluidized bed boiler from a thermal power plant

    Institute of Scientific and Technical Information of China (English)

    朱化军; 徐俊; 刘伟京; 涂勇; 陈兆林; 张鸿涛

    2012-01-01

    以市政污泥为原料,利用某热电厂循环流化床锅炉进行协同焚烧验证研究.试验表明,循环流化床锅炉热电厂污泥协同焚烧的泥煤质量比可在0~0.3之间根据用户需求调节,炉膛燃烧温度〉850℃,烟气停留时间2.59s,符合《生活垃圾焚烧污染控制标准》(GB18485—2001)中850℃烟气停留时间〉2s的要求;脱硫塔烟气进出口NOx、SO2浓度低于锅炉未掺烧污泥前浓度,粉煤灰重金属含量低于《农用粉煤灰中污染物控制标准》(GB8173-87)中粉煤灰农用标准限值(在酸性土壤上:Cd5mg·kg-1,Pb250mg·kg-1),粉煤灰烧失量满足掺混前Ⅱ级品质要求.因此,循环流化床锅炉污泥协同焚烧可有效解决当地城镇污水厂污泥出路,最终实现污泥妥善、安全处置需求.%Incineration of municipal sludge with coal was investigated in a circulation fluidized bed from a thermal power plant.The results show that sludge /coal mass ratio was adjustable between 0 and 0.3 in the circulating fluidized bed boiler according to customer demand.The operating condition of combustion temperature was over 850 ℃ and flue gas residence time was 2.59s under the conditions,which complied with the requirement of the flue gas residence time ( 2 s) at 850 ℃ as prescribed in the pollution control standard on the municipal solid waste incineration (GB18485—2001).The smoke concentrations import and export of the desulfurization tower were lower than the pre-mixing sludge concentration.The heavy metal content in fly ash met the standard limit (Cd 5 mg·kg-1,Pb 250 mg·kg-1) in acid soil of control standards of pollutants in fly ash for agricultural use,and the fly-ash burning-loss amount met the Ⅱgrade quality requirements.Therefore,incineration of municipal sludge in the circulation fluidized bed was an effective way in municipal sludge treatment,which would finally achieve the safe disposal of sludge from local urban sewage plant.

  19. Clustering behavior of solid particles in two-dimensional liquid-solid fluidized-beds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, the clustering behavior of solid particles in a two-dimensional (2D) liquid-solid fluidized-bed was studied by using the charge coupled devices (CCD) imaging measuring and processing technique and was characterized by fractal analysis. CCD images show that the distribution of solid particles in the 2D liquid-solid fluidised-bed is not uniform and self-organization behavior of solid particles was observed under the present experimental conditions. The solid particles move up in the 2D fluidized-bed in groups or clusters whose configurations are often in the form of horizontal strands. The box fractal dimension of the cluster images in the 2D liquid-solid fluidized-bed increases with the rising of solid holdup and reduces with the increment of solid particle diameter and superficial liquid velocity. At given solid holdup and solid particle size,the lighter particles show smaller fractal dimensions.

  20. Particle size distribution of ashes and the behaviour of metals when firing Salix in a circulating fluidized bed boiler (CFB); Askans partikelfraktionsfoerdelning och metallernas beteende vid eldning av Salix i en CFB-panna

    Energy Technology Data Exchange (ETDEWEB)

    Sfiris, G.; Johansson, A. [Vattenfall Utveckling AB, Stockholm (Sweden); Valmari, T.; Kauppinen, E.; Pyykoenen, J.; Lyyraenen, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    1999-07-01

    This project is part of the Ash Recovery Programme aimed at establishing the environmental, technical and financial preconditions for returning wood ash to the forest. The programme is funded jointly by NUTEK, Sydkraft and Vattenfall. This report summarises the results of the experimental and modelling work to study the behaviour of the metals (especially Cd and K), after burning Salix in a 3-12 MW Circulating Fluidized Bed (CFB) boiler. The purpose of the study was to determine, using the experimental data, where cadmium and potassium condense, on what size particles they condense, and the decisive parameters governing these processes. Measurements of the fly ash particle size distribution carried out with a Berner Low Pressure Impactor (BLPI), coupled to a pre-cyclone. Samples were collected from three points: in the convection path at 650 deg C, after the convection path but before the secondary cyclone (160 deg C), and after the bag house (150 deg C). Wet chemical sampling was made for Cd, K, Zn and Pb, with three types of sampling equipment: collection of both particles and gas, collection of particles only, and analysis of the gas phase only. Analysis was made of samples from two places in the convection path (650 deg C and 250 deg C). Samples of bed material, bottom ash and fly ash have been subjected to scanning electron microscopy (SEM), and in addition a few fly ash particles, sampled after the convection path, were subjected to energy dispersive X-ray analysis (EDX). Based on experimental results, modelling work was carried out with an equilibrium model and with a general aerosol computer model ABC (Aerosol Behaviour in Combustion)

  1. Heat Transfer Characteristic in Oxy-fuel Circulating Fluidized Bed Boiler%富氧燃烧循环流化床锅炉炉内传热特性

    Institute of Scientific and Technical Information of China (English)

    王春波; 侯伟军; 陈传敏; 霍志红

    2011-01-01

    针对富氧燃烧循环流化床锅炉(circulating fluidized bed boiler,CFBB)炉内传热特性进行了研究。考虑气体辐射对传热系数的影响,建立了CFBB富氧燃烧下的传热模型。以一台440t/h循环流化床锅炉为例,通过模型分析了炉内传热情况,并和空气燃烧模式下的传热特性进行比较。进行了氧气浓度在30%、50%、70%气氛下的CFBB炉膛概念性设计。在循环流化床锅炉炉内传热中,灰占主导作用,烟气成分变化对传热系数影响不大。氧气浓度越高,越有必要设置外置换热器来维持炉膛正常运行。%The heat transfer in oxy-fuel circulating fluidized bed boiler (CFBB) was investigated. A model which considers the influence of gases radiation on heat transfer coefficient was set. Take a 440t/h CFBB for example, the heat transfer in furnace was calculated and the results were compared with air-fired CFBB. The model shows the heat transfer coefficient is not be changed greatly in oxy-fuel combustion, because the heat transfer is dominated by the effect of particles, not depend on gases composition. The concept design of oxy-fuel CFBB was done at 30%, 50%, and 70% O2 concentration. It was found the higher concentration of oxygen the more necessary to set an external heat exchanger to keep a normal operation of the furnace.

  2. 基于Aspen Plus软件的循环流化床烟气脱硫模型%A model of flue gas desulfurization for circulating fluidized bed using Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    颜湘华; 朱廷钰; 王威; 何京东

    2009-01-01

    Model study and flow simulation of circulating fluidized bed flue gas desulfurization (CFB-FGD) were described in this pa-per. The mathematic model of flue gas desulfurization for circulating fluidized bed (CFB) was buih on the basis of element analysis for mass transfer of SO2. The enhancement of the desulfurization reaction in the process of mass transfer of SO2 was analyzed with the doub-le-membrane theory in the model. And the real formation process of slurry droplet was accounted with the theory of inertia collision. And then a simulation study of CFB-FGD was conducted based on Aspen Plus, where a module subroutine was programmed in FOR-TRAN based on this model. The influences of the key parameters such as calcium-to-sulfur ration (Ca/S), flux of spay water, concen-tration of sorbent particles and water drop size on the desulfurization efficiency were analyzed. The modeling results were compared with the experimental data and the comparing results showed that this model could preferably predict the real trends, This paper would help the application of CFB-FGD as references.%本文研究和模拟循环流化床烟气脱硫的流程和模型.以微元分析SO2的传质为基础,建立循环流化床烟气脱硫的数学模型,模型用双膜理论分析脱硫反应对SO2传质过程的增强影响,并采用惯性碰撞理论解释浆滴的形成过程.借助Aspen Plus过程模拟平台,用FORTRAN语言编写基于该模型的用户单元模块,模拟循环流化床烟气脱硫工艺,分析Ca/S、增湿水量、塔内颗粒物浓度、水滴粒径等参数对脱硫的影响,模拟计算结果和实验数据的对比显示模型能如实反映实际的趋势.本文为应用循环流化床烟气脱硫技术提供参考.

  3. A Shannon Information Entropy Analysis of Pressure Fluctuation Signals From an Underfed Circulating Spouted Bed%底饲进料循环喷动床内压力脉动信号的SHANNON信息熵分析

    Institute of Scientific and Technical Information of China (English)

    陶敏; 金保升; 杨亚平; 薛玉兰

    2009-01-01

    To study the gas-solid two phase flow characteristics of an underfed circulating spouted bed,the authors have measured the pressure fluctuation signals at various heights in the axial direction of a reaction tower through a cold-state test,analyzed the pressure signals by using Shannon information entropy and compared the influence of different operating conditions on the gas-solid two-phase flow in the tower.It has been found that the pressure fluctuation and its power spectrum display different characteristics at different heights of bed layers and Shannon information entropy can reflect very well the complexity and stability degree of the characteristic signals.Enhancing the fluidized velocity and circulation ratio can lead to an increase of particle concentration in the axial direction of the tower,thus enhancing the amplitude of the pressure fluctuation.To increase the jet flow velocity and heighten the nozzle location can intensify the gas-solid turbulent flow at the bottom of the tower and Shannon information entropy can be increased accordingly.%为了研究底饲进料循环喷动床内气固两相流的流动特性,通过冷态实验测量反应塔内轴向不同高度上的压力脉动信号.应用SHANNON信息熵分析压力信号,并比较不同操作条件对塔内气固流动的影响.结果表明:压力脉动及其功率谱在不同床层高度上表现出不同的特性;SHANNON信息熵能够很好地反映特征信号的复杂程度和稳定程度;提高流化速度和循环倍率能够导致塔内轴向上的颗粒浓度上升,从而使压力脉动的幅度增加;提高喷射速度和喷嘴位置,能使反应塔底部气固湍动更加强烈,SHANNON信息熵随之上升.

  4. Effect of biomass-sulfur interaction on ash composition and agglomeration for the co-combustion of high-sulfur lignite coals and olive cake in a circulating fluidized bed combustor.

    Science.gov (United States)

    Varol, Murat; Atimtay, Aysel T

    2015-12-01

    This study aimed to investigate the effect of biomass-sulfur interaction on ash composition and agglomeration for the co-combustion of high-sulfur lignite coals and olive cake in a circulating fluidized bed combustor. The tests included co-combustion of 50-50% by wt. mixtures of Bursa-Orhaneli lignite+olive cake and Denizli-Kale lignite+olive cake, with and without limestone addition. Ash samples were subjected to XRF, XRD and SEM/EDS analyses. While MgO was high in the bottom ash for Bursa-Orhaneli lignite and olive cake mixture, Al2O3 was high for Denizli-Kale lignite and olive cake mixture. Due to high Al2O3 content, Muscovite was the dominant phase in the bottom ash of Denizli Kale. CaO in the bottom ash has increased for both fuel mixtures due to limestone addition. K was in Arcanite phase in the co-combustion test of Bursa/Orhaneli lignite and olive cake, however, it mostly appeared in Potassium Calcium Sulfate phase with limestone addition.

  5. 循环流化床锅炉结焦原因分析及对策%Analysis of Causes for Coking of Circulating Fluidized Bed Boiler and Counter-Measures

    Institute of Scientific and Technical Information of China (English)

    王伟

    2011-01-01

    结焦是循环流化床锅炉运行中较为常见的故障,直接影响到锅炉的安全经济运行.根据几年来流化床锅炉调试和运行经验,循环流化床锅炉结焦的原因主要是炉内流化工况不良或操作失误等,使床料局部或整体温度超过灰的熔点.提出加强燃料监督、强化运行管理、严格控制设备参数、降低飞灰残碳含量等措施,以避免循环流化床锅炉结焦.%Coking is a common trouble in the operation of the circulating fluidized bed boiler, directly affecting the safe and economic operation of the boiler. Based on the experience gained in the debugging and operation of the boiler, the reasons for coking are mainly poor fluidization work condition in the boiler or faulty operation, causing the local or bulk temperature of the charge to exceed the ash fusion point. Measures are proposed, including strengthening the supervision of the fuel and operation management, strictly controlling the equipment parameters, and lowering the residual carbon content of the fly ash, so as to prevent coking in the furnace.

  6. 柱磨机在循环流化床炉内脱硫的应用研究%Application Research on Column Mill for Desulfurization of Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    闫事忠; 白鹭; 刘晓飞

    2016-01-01

    Due to low pollutant emission and clean combustion, CFB boiler technology gets rapid development. The influence of lime stone's particle size on the boiler desulfurization efficiency is discussed. According to the nature of the prepared lime stone powder milled by column mill, the application prospect of column mill lime stone powder system for desulphurization in circulating fluidized bed power plant is explored.%指出循环流化床锅炉技术因其高效低污染的清洁燃烧方式得到迅速发展。主要从石灰石粒径对循环流化床锅炉炉内脱硫效率的影响为出发点进行讨论,根据柱磨机磨粉系统所制备的石灰石粉性质,探讨该系统在循环流化床电厂脱硫中的应用前景。

  7. Development of a lignite-fired power plant concept with integrated pressurised fluidised-bed drying and fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Leidich, F.U.; Breitenfelder, R. [ALSTOM Power Generation AG, Mannheim (Germany); Mandel, H. [Vattenfall Europe Generation AG and Co., Cottbus (Germany); Krautz, J. [Technical Univ., Cottbus (Germany); Gniazdowski, M. [Babcock Borsik Service GmbH, Oberhausen (Germany)

    2005-07-01

    In the coming decades, lignite will become one of the most important fuels for power production in Germany. In the last five years, Vattenfall Europe and RWE have put power plants of the 800-1000 MW class with efficiency of up to more than 43% into service. Four to five per cent efficiency can further be gained by using pre-dried lignite as fuel (BOA plus concept of RWE). Additional steps are possible if the lignite-drying process and combustion are operated under pressure. This paper describes the first steps based on the A.M. technology whereby the waste heat of fuel cells is used for operation of the lignite dryer to achieve highest efficiency levels. (author)

  8. Fluidised bed membrane reactor for ultrapure hydrogen production via methane steam reforming: Experimental demonstration and model validation

    NARCIS (Netherlands)

    Patil, Charudatta S.; Sint Annaland, van Martin; Kuipers, J.A.M.

    2007-01-01

    Hydrogen is emerging as a future alternative for mobile and stationary energy carriers in addition to its use in chemical and petrochemical applications. A novel multifunctional reactor concept has been developed for the production of ultrapure hydrogen View the MathML source from light hydrocarbons

  9. Flow Pattern Identification of Fluidized Beds Using ECT

    Institute of Scientific and Technical Information of China (English)

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

    2001-01-01

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

  10. Research report of FY 1997 on the environmentally acceptable coal utilization system introduction support project. Demonstration project of circulating fluidized bed boiler (Jinzhou Coal-Thermal Power Corporation); 1997 nendo seika hokokusho (kankyo chowagata sekitan riyo system donyu shien jigyo). Junkan ryudosho boiler ni kakawaru jissho jigyo (Jinzhou netsuden sokoji)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    To verify the clean coal technology to be diffused in China and consolidate its diffusion basis, demonstration project of circulating fluidized bed boiler was conducted through the cooperation with China which is positive in its introduction. This report describes its characteristics. Coal and limestone are supplied in a lower part of combustion chamber, and are mixed with circulating ash by fluidized air for combustion. Densely fluidized bed the same as the bubbling fluidized bed is formed in the lower part of combustion chamber, which provides excellent stability in ignition and combustion. Particles including ash, char and limestone formed during the combustion are discharged into the cyclone through the convection heat transfer part at the outlet of combustion chamber with the combustion gas flow. Since the gas temperature is lowered to 400 to 500degC at the convection heat transfer part, troubles of the ash circulating system can be prevented. The combustion gas separated from ash at the cyclone is discharged through the heat exchanger and precipitator, and the collected ash is returned to the lower part of combustion chamber. In FY 1997, design, fabrication, procurement/inspection, field survey/meeting, survey of visitors/meeting, and education were carried out. 4 figs., 4 tabs.

  11. 循环流化床燃煤固硫灰制备地聚合物的研究%Study on Preparation of the Circulating Fludized Bed Combustion(CFBC) Fly Ash-based Geopolymer

    Institute of Scientific and Technical Information of China (English)

    霍琳; 李军; 卢忠远; 张文清; 胡昌华

    2012-01-01

    The geopolymer was a new kind of cementitious material with excellent performance. The synthesis of circulating fludized bed combustion(CFBC) fly ash-based geopolymer has been studied. The optimal conditions were as follows: the modulus and dosage of sodium silicate solution were 1. 5 and 25% , respectively, the alkaline content of system was 30% and curing under 90℃. All that lead to the 7 d compressive strength of geopolymer was 58. 9 MPa. The fire-resist properties of geopolymer was also studied. Results showed that geopolymer, which cured under low temperature, experienced 1000℃ can stimulate the improvement of strength.%地聚合物是具有优良性能的新型胶凝材料,研究了用循环流化床固硫灰制备地聚合物的适宜条件.结果表明,当水玻璃模数M=1.5,水玻璃掺量为25%,体系碱含量为30%时制备的地聚合物强度较高,较高的养护温度有利于提高早期强度,7d抗压强度最高为58.9 MPa.研究了地聚合物的高温性能,实验发现早期养护温度较低的地聚合物经历1 000℃的高温后强度能够进一步增长.

  12. The experimental study on new type baking-free brick prepared the circulating fluidized bed boiler (CFBB) ash%循环流化床锅炉灰渣制备新型免烧砖的试验研究

    Institute of Scientific and Technical Information of China (English)

    黄鑫; 夏举佩; 周新涛

    2014-01-01

    本文以循环流化床锅炉(C FBB )灰渣为主要原料,通过实验获得了其制备免烧砖的最佳工艺配料为:石灰7%、飞灰43%、底渣30%、骨料瓜子石20%。通过蒸汽养护和自然养护对比,发现在低石灰掺量时,自然养护效果明显低于蒸汽养护,但随着石灰用量的增加,二者差异逐渐缩小,当高于7%时,检测结果基本一致,在此基础上,通过扩大性工业试验,采用自然养护方式,可生产标号为150的免烧砖砌块。%In this paper ,circulating fluidized bed boiler (CFBB) ash is used as the main raw material for preparing baking free brick to obtain through experiment the optimal ingredients as follows :7% lime ,43%fly ash ,30% bottom ash ,20% aggregate of oval stone .By steam curing and natural curing contrast ,we find that the effect of nature curing is significantly lower than the steam curing .But with the increasing of lime dosage ,the difference is gradually reduced .When lime dosage is higher than 7% ,the test results are basically consistent .On this basis ,unburned block labeled 150 can be produced using natural curing method through the expansion of industrial test .

  13. DNA-induced inter-particle cross-linking during expanded bed adsorption chromatography - Impact on future support design

    DEFF Research Database (Denmark)

    Theodossiou, Irini; Thomas, Owen R. T.

    2002-01-01

    of the mean hydrated particle radii, the anion-exchangers were observed to split into three distinct, but different clusters in each case. The highest index of surface packing of DNA was observed for two prototype pellicular supports, one derivatised with highly charged high molecular mass polyethyleneimine...... of anion-exchangers, the bed heights dropped progressively as DNA molecules physically cross-linked neighbouring adsorbent particles together, to form severely aggregated fluidised beds. In plots of dynamic binding capacities and absolute changes in bed porosity at maximum contraction, against the inverse...... exhibited a three-fold higher tendency to interact with neighbouring particles in the presence of DNA than that of the dextran DEAE support. The implications of these findings on the design of future expanded bed materials for separation of both proteins and nucleic acids are discussed....

  14. Fetal Circulation

    Science.gov (United States)

    ... Pressure High Blood Pressure Tools & Resources Stroke More Fetal Circulation Updated:Jul 8,2016 click to enlarge The ... fetal heart. These two bypass pathways in the fetal circulation make it possible for most fetuses to survive ...

  15. 金精矿提金三相循环流化床系统的神经网络建模%Neural Network Modeling of System of Extracting Gold from Gold Concentrate with Three-phase Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    李松; 李征; 赵洋; 李登新

    2011-01-01

    三相循环流化床床层压力是影响提金效率的一个重要因素,但床层压力大小受进气速度、固含率、金精矿粒径大小、循环流化床自身设计结构等多种因素影响,关系复杂,难以建立精确的数学模型;针对以上问题,首先通过实验确定了影响床层压力大小的主次因素,为简化问题进行建模做了准备;然后对三相循环流化床提金过程的压力特性进行多工况实验,采用基于LM( Levenberg- Marquardt)算法的BP神经网络建立了金精矿提金三相循环流化床床层压力的神经网络模型,并进行了校验;研究结果表明该算法收敛速度快,所建模型精度高且泛化能力强,该模型为三相循环流化床的监控提供了基础.%The stratified pressure of Three-phase Circulating Fluidized Bed (TCFB) is one important factor which affects the efficiency of extracting gold from gold concentrate. But the size of the stratified pressure is affected by many factors, such as the rate of the flowing gas. Solid holdup, the design structure of TCFB, etc. And their relationship is complicated, it' s difficult to establish accurate mathematical model. Aimed at this problem, firstly, the main factors and the secondary factors which affect the size of the stratified pressure have been determined by experiments, based on this, the problem was simplified to prepare for the modeling. Then the stratified pressure of TCFB in extracting gold from gold concentrate process was experimentally investigated, and taking advantage of BP neural network based on Levenberg - Marquardt (LM) algorithm, the neural network model is established and verified. The result showed that the LM algorithm has a rapid convergent speed, the model has high precision and good generalization ability, and the model provides a foundation to monitor TCFB.

  16. GREENHOUSE GAS EMISSIONS CONTROL BY OXYGEN FIRING IN CIRCULATING FLUIDIZED BED BOILERS: PHASE II--PILOT SCALE TESTING AND UPDATED PERFORMANCE AND ECONOMICS FOR OXYGEN FIRED CFB WITH CO2 CAPTURE

    Energy Technology Data Exchange (ETDEWEB)

    Nsakala ya Nsakala; Gregory N. Liljedahl; David G. Turek

    2004-10-27

    Because fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this Phase II study, ALSTOM Power Inc. (ALSTOM) has investigated one promising near-term coal fired power plant configuration designed to capture CO{sub 2} from effluent gas streams for sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}, along with some moisture, nitrogen, oxygen, and trace gases like SO{sub 2} and NO{sub x}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be more economical than in PC or Stoker firing, because recirculated gas flow can be reduced significantly. Oxygen-fired PC and Stoker units require large quantities of recirculated flue gas to maintain acceptable furnace temperatures. Oxygen-fired CFB units, on the other hand, can accomplish this by additional cooling of recirculated solids. The reduced recirculated gas flow with CFB plants results in significant Boiler Island cost savings resulting from reduced component The overall objective of the Phase II workscope, which is the subject of this report, is to generate a refined technical and economic evaluation of the Oxygen fired CFB case (Case-2 from Phase I) utilizing the information learned from pilot-scale testing of this concept. The objective of the pilot-scale testing was to generate detailed technical data needed to establish advanced CFB design requirements and performance when firing coals and

  17. Study on production of aerated concrete by circulating fluidized bed fly ash%循环流化床粉煤灰加气混凝土制备研究

    Institute of Scientific and Technical Information of China (English)

    徐正坦

    2014-01-01

    利用X射线荧光光谱仪、X RD等检测手段对循环流化床粉煤灰进行化学成分定性和定量分析,然后确定配合比:粉煤灰65%,水泥12%,石灰20%,石膏3%。主要研究了在蒸压养护条件下,不同水料比、不同铝粉添加量、不同无机外加剂硫酸钠、氯化钙添加量对加气混凝土砌块容重和强度的影响,研究发现最佳水料比为0.65,最佳铝粉掺量为0.1%,无机外加剂硫酸钠对加气混凝土砌块的容重和强度影响不大,而添加0.25%的氯化钙比无外加剂条件下强度提高了40%,达到4.55 M Pa ,且容重为910 kg/m3,随着氯化钙量的增加,强度反而下降。%In this article ,chemical compositions of circulating fluidized bed fly ash were gualitative and guantitative analyzed by using X-ray fluorescence spectrometry and X-ray diffraction ,then confirmed the suitable match ratio :fly ash 65 percent ,cement 12 percent ,lime 20 percent ,gypsum 3 percent . Primarily studied on autoclaved condition ,the effects of different amounts of water-binder ratio ,Al powder addition ,inorganic admixture (sodium sulphate ,calcium chloride) addition on volume weight and compression strength .The result show that the best water-binder ratio was 0 .65 ,the best Al powder addition was 0 .1 percent ,sodium sulphate was less effect on volume weight and compression strength of aerated concrete ,however compare with non-admixture ,compression strength raised by 40 percent while adding 0 .25 percent calcium chloride ,it reached 4 .55 MPa and 910 kg/m3 ,with increasing of addition of calcium chloride ,the compression strength of aerated concrete decrease .

  18. Study on Production of Aerated Concrete by Circulating Fluidized Bed Fly ASH%循环流化床粉煤灰加气混凝土制备研究

    Institute of Scientific and Technical Information of China (English)

    刘心中; 翁仁贵; 陈祖兴

    2009-01-01

    In this article, chemical compositions of circulating fluidized bed fly ash were gualitative and guantitative analyzed by using X-ray fluorescence spectrometry and X-ray diffraction, then determined the suitable match ratio: fly ash 65%, cement 12%, lime 20%, gypsum 3%. Primarily studied on autoclaved condition, the effects of different amounts of water-binder ratio, AI powder addi-tion, inorganic admixture (sodium sulphate, calcium chloride) addition on volume weight and compression strength. The result show that the best water-binder ratio was 0.65, the best Al powder addition was 0.1%, sodium sulphate was less effect on volume weight and compression strength of aerated concrete, however compare with non-admixture, compression strength raised by 40% while adding 0.25% calcium chloride, it reached 4.55 MPa and 900 kg/m3, with increasing of addition of calcium chloride, the compression strength of aerated concrete decrease.%利用X射线荧光光谱仪、XRD等检测手段对循环流化床粉煤灰进行化学成分定性和定量分析,然后确定其质量配合比:粉煤灰65%,水泥12%,石灰20%,石膏3%.主要研究了在蒸压养护条件下,不同水料比、不同铝粉添加量、不同无机添加剂硫酸钠、氯化钙添加量对加气混凝土砌块容重和强度的影响,研究发现最佳水料比为0.65,最佳铝粉掺量为0.1%,无机添加剂硫酸钠对加气混凝土砌块的容重和强度影响不大,而添加0.25%的氯化钙比无添加剂条件下强度提高了40%,达到4.55 MPa,容重为900 kg/m3,随着氯化钙量的增加,强度反而下降.

  19. Variability of bed drag on cohesive beds under wave action

    Science.gov (United States)

    Safak, Ilgar

    2016-01-01

    Drag force at the bed acting on water flow is a major control on water circulation and sediment transport. Bed drag has been thoroughly studied in sandy waters, but less so in muddy coastal waters. The variation of bed drag on a muddy shelf is investigated here using field observations of currents, waves, and sediment concentration collected during moderate wind and wave events. To estimate bottom shear stress and the bed drag coefficient, an indirect empirical method of logarithmic fitting to current velocity profiles (log-law), a bottom boundary layer model for combined wave-current flow, and a direct method that uses turbulent fluctuations of velocity are used. The overestimation by the log-law is significantly reduced by taking turbulence suppression due to sediment-induced stratification into account. The best agreement between the model and the direct estimates is obtained by using a hydraulic roughness of 10  m in the model. Direct estimate of bed drag on the muddy bed is found to have a decreasing trend with increasing current speed, and is estimated to be around 0.0025 in conditions where wave-induced flow is relatively weak. Bed drag shows an increase (up to fourfold) with increasing wave energy. These findings can be used to test the bed drag parameterizations in hydrodynamic and sediment transport models and the skills of these models in predicting flows in muddy environments.

  20. 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

  1. 21 CFR 890.5160 - Air-fluidized bed.

    Science.gov (United States)

    2010-04-01

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

  2. Fluidization Characteristics of a Prototype Fluidized Bed Reactor

    Directory of Open Access Journals (Sweden)

    F. ABERUAGBA

    2005-01-01

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

  3. Nearshore circulation

    NARCIS (Netherlands)

    Battjes, J.A.; Sobey, R.J.; Stive, M.J.F.

    1990-01-01

    Shelf circulation is driven primarily by wind- and tide-induced forces. It is laterally only weakly constrained so that the geostrophic (Coriolis) acceleration is manifest in the response. Nearshore circulation on the other hand is dominated by wave-induced forces associated with shallow-water. wave

  4. 循环流化床富氧燃烧NO和N2O的排放特性%NO and N2O Emission Characteristics of Oxy-Fuel Circulating Fluidized Bed Combustion

    Institute of Scientific and Technical Information of China (English)

    李伟; 李诗媛; 徐明新; 吕清刚

    2015-01-01

    Experiments were carried out in a 50,kW circulating fluidized bed(CFB)combustor under the O2/CO2at-mosphere. The combustion temperature was within the range of 800—950,℃,and the inlet oxygen concentration was within the range of 25%—50%,. The effects of combustion temperature,inlet oxygen concentration and excess oxy-gen coefficient on NO and N2O emission characteristics were studied. The results show that the N conversion rate un-der the O2/CO2,firing mode is much lower than that under the air firing mode. As the inlet oxygen concentration in-creases,the NO emission increases and while N2O emission decreases. With the increase of excess oxygen coefficient,both NO and N2O emissions and N conversion rate increase. It can be concluded that increasing tempera-ture and inlet oxygen concentration and decreasing excess oxygen coefficient areboth beneficial to the decrease of N conversion rate oxy-fuel CFB combustion.%在50,kW循环流化床燃烧试验台上对大同煤和神木半焦进行了O2/CO2气氛的富氧燃烧试验,试验的进口氧气体积分数为25%,~50%,,燃烧温度为800~950,℃.试验研究的目标是获得燃烧温度、进口氧气体积分数和过量氧气系数等因素对循环流化床富氧燃烧过程中 NO 和 N2O 的排放特性以及燃料 N 转化率的影响.研究结果表明,与空气气氛相比,O2/CO2气氛下的燃料N转化率明显降低;随着进口氧气体积分数增加,NO的排放下降,而N2O 的排放则升高;随着过量氧气系数的增加,NO、N2O 的排放以及燃料 N 转化率均呈增加趋势.在循环流化床富氧燃烧中,提高燃烧温度、进口氧气体积分数以及降低过量氧气系数都能有效降低燃料N转化率,抑制氮氧化物的排放.

  5. Experimental Investigation on Addition of Anticorrosive Agent in a 50-MW Biomass-Fired Circulating Fluidized Bed Boiler%生物质循环流化床锅炉掺烧防腐蚀剂的试验研究

    Institute of Scientific and Technical Information of China (English)

    宋景慧; 谭巍

    2014-01-01

    Experiments on combustion of pure biomass and biomass with anticorrosive agent were carried out in a 50-MW biomass-fired circulating fluidized bed boiler. The anticorrosive agent has a porous structure and mainly contains magnesium oxide (MgO), kaolin, activated alumina (Al2O3) and foamer. Results obtained in experiments show that, boiler thermal efficiency was weakly influenced by the anticorrosive agent, and contents of K and Cl in flue ash decreased as contrast to the increase of K and Cl in furnace slag. When the mass percentage of anticorrosive agent is 3%, in the flue ash, the K values ranged from 7.62%to 5.69%, and Cl values reduced from 3.86%to 2.35%. While in furnace slag, the values K varied from 4.03%to 4.71%, and Cl values increased from 756.58 mg/kg to 1 121.31 mg/kg. Due to the anticorrosive agent, the content of HCl in flue gas decreased from 25 mg/Nm3 to 15 mg/Nm3, as the emission of NO increased from 268 mg/Nm3 to 309 mg/Nm3.%在亚洲最大的50 MW生物质循环流化床直燃锅炉上进行了掺烧防腐蚀剂的燃烧试验,防腐蚀剂采用多孔膜结构,主要成分是MgO、高岭土、活性Al2O3和发泡剂,试验结果表明:掺烧防腐蚀剂不会降低锅炉热效率,且能够有效地降低飞灰中K、Cl元素的含量,将其固留在炉渣中。当防腐蚀剂添加量占总燃料质量的3%时,飞灰中的K元素含量由7.62%下降为5.69%,Cl元素含量由3.86%下降为2.35%;而炉渣中的K元素含量由4.03%上升为4.71%,Cl元素含量由756.58 mg/kg上升为1121.31 mg/kg;同时烟气中的HCl排放量由25 mg/Nm3下降为15 mg/Nm3,NO含量由268 mg/Nm3上升为309 mg/Nm3。

  6. Direct Utilization of Circulating Fluidized Bed Combustion Ash of Distilled Spirits Lees as Fertilizer%白酒糟循环流化床燃烧灰直接肥料化利用

    Institute of Scientific and Technical Information of China (English)

    宋扬; 汪印; 姚常斌; 张玉明; 王昶; 易彬; 杨俊; 许光文

    2011-01-01

    研究了白酒糟循环流化床燃烧灰直接作为肥料的可能性和效果,以其为肥料种植油菜,考察了油菜在5种土壤中发芽和生长情况.结果表明,白酒糟燃烧灰对不同生长阶段的油菜有不同影响,对壤质土中的油菜发芽有抑制作用,但能明显改善粘性土壤中油菜的生长环境,油菜的净增量和产量都有明显增加.白酒糟燃烧灰还能提高酸性土壤pH值,使土壤环境向中性(pH 6.97~7.74)变,有利于腐殖酸分解和植物生长.土壤与白酒糟燃烧灰质量比为5:1时,与原土相比,泸州国窖红土壤、泸州青稞土壤及富阳土壤中油菜净增量分别为80.1%,80.9%,163.6%,表明利用白酒糟燃烧灰作为植物生长肥料是可行的.%The feasibility of utilizing the circulating fluidized bed combustion ash of distilled spirits lees as fertilizer was investigated. The rape culture experiment was carried out in 5 different kinds of soils, and the rape growth states in the germination and growth stages were measured to evaluate the effect of adding ash to the soils as fertilizer. The results show that the ash exhibited different effects on the rape growth in different culture stages. There was an antibiastic effect on the rape growth in the germination stage in a loamy soil, but the rape growth was much improved when adding the ash to a clayey soil. The latter led the mature rape to having obviously increased net height and weight. The ash could change the pH value of acid soil into neutral state, facilitating the humic acid decomposition and plant growth. Comparing the soils at soil:ash=5:l(ω) with original soil, the increased amplitudes of net height of rape in Guojiaohong Turang, Qingke Turang and Fuyang Turang were 80.1%, 80.9% and 163.6%, respectively. As consequence, it was feasible and effective to use directly the combustion ash of distilled spirits lees as fertilizer.

  7. Study of the Drying Kinetics of “Granny Smith” Apple in Fluid Bed Dryer

    Directory of Open Access Journals (Sweden)

    Darko Velić

    2007-12-01

    Full Text Available The drying characteristics of “Granny Smith” apple were investigated using a bench-scale fluidised bed drier at different temperatures and using blanching in hot water as pre treatment. Temperatures of fluidisation for non-treated and treated samples were 50, 60, 70 and 80 oC and airflow velocity 3.50 m s-1. The aim of the experiment was to get apples with approximately 9% water content, with good texture, rehydration capability and colour quality. The effect of temperatures and pre-treatment on the quality of dried apple samples was determined on the basis of colour and volume changes and reconstitution characteristics. Th e kinetic equations were estimated using logarithmic model. The results of the estimation have exhibited correspondence to experimental results. As a result of drying of non-treated apple at higher temperatures, drying time shortens, while rehydration properties improve. On the other hand, with the increase of the drying temperature, overall colour changes (ΔE of non-treated samples increase. The best results, shorter drying time and better rehydration properties, were obtained when samples were pre-treated by blanching in hot water.

  8. Spouted bed electrowinning of zinc: Part II. Investigations of the dynamics of particles in large thin spouted beds

    Science.gov (United States)

    Verma, A.; Evans, J. W.; Salas-Morales, Juan Carlos

    1997-02-01

    The behavior of particles in thin spouted beds, mostly equipped with draft tubes, has been investigated. Three apparatuses have been used: a laboratory-scale cylindrical bed, a 2-m-tall “flat” (rectangular cross section) bed and a 2-m-wide flat bed, the last equipped with multiple draft tubes. Most of the results were obtained on the tall bed. Minimum spouting flow rate, pressure distribution, particle velocities, and solid circulation rates were determined as a function of bed geometry (including draft tube dimensions and position). Observations were made of the direction of liquid flow in the bed outside the draft tube and of the occurrence of zones in the bed where the particles appeared stationary. The wide bed was used to determine that there is a maximum separation between draft tubes beyond which particles cannot be kept in motion across the whole width of the bed.

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

    Science.gov (United States)

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

    1981-01-01

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

  10. Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes

    Science.gov (United States)

    Talmud, Fred M.; Garcia-Mallol, Juan-Antonio

    1980-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to a water drum and in the path of the air and the gaseous products of combustion exiting from the bed. Another portion of the tubes pass through the bed and extend at an angle to the upper surface of the bed.

  11. Solids mixing in spouted beds

    OpenAIRE

    Cook, H. H.; Bridgwater, J.; Professor J. Bridgwater

    1981-01-01

    Many industrial processes require contact between particles and a fluid or spray in order to effect drying, coating or granulation. One device capable of contacting fluid and particles efficiently is a spouted bed in which a jet of fluid is injected into solid particles. This forms an open channel or spout and induces material circulation in a downward moving annulus. For the continuous throughput of solids, knowledge is required of the mixing and particle motions within th...

  12. Circulation economics

    DEFF Research Database (Denmark)

    Ingebrigtsen, Stig; Jakobsen, Ove

    2006-01-01

    presupposes a perspective integrating economic, natural and cultural values. Third, to organize the interplay between all stakeholders we introduce an arena for communicative cooperation. Originality/value - The paper concludes that circulation economics presupposes a change in paradigm, from a mechanistic...

  13. A Cold Model Experimental Study on the Flow Characterisitcs of Bed Baterial in A Fluidized ed Bottom Ash Cooler in a CFB Boiler

    Institute of Scientific and Technical Information of China (English)

    LuXiaofeng; LiYourong

    2000-01-01

    A cold model experimental study on the flowing characteristics of bed meterial between a fluidized bed ash cooler and a furnace of CFB boiler were discussed in this paper.The research results showed that flowing status of the bed material in a bubbling bed,which was run with a circulating fluidized bed together in parallel operation,was influenced by the pressure difference between the CFB and the bubbling bed,the switch status of unlocking air ,and the structure of the exit of the bubbling bed.There was a circulating flow of bed material between CFB and bubbling bed.

  14. Fuel gas production from renewable biomass in a circulating fluidized bed as a bases for zero-CO{sub 2} power generation in a combined-cycle power plant; Brenngaserzeugung aus nachwachsenden Biomassen in der zirkulierenden Wirbelschicht als Grundlage fuer eine CO{sub 2}-neutrale Stromerzeugung in einem GUD Kraftwerk

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, J.; Loeffler, J.; Hirschfelder, H. [Lurgi Energie und Umwelt GmbH, Frankfurt am Main (Germany)

    1996-12-31

    A pilot circulating fluidized bed plant in the range of 1.7 MW{sub th} has been operated successfully with fossil fuels, residues, wood bark and wood chips, reet grass and sorghum pellets. Depending on the specifications for product gas and fuel quality, air, oxygen-enriched air or oxygen/steam mixtures are used as gasification agents in the gas generator. (orig) [Deutsch] In einer ZWS-Pilotanlage mit ca. 1.7 MW thermischer Leistung wurden bisher ausser fossilen und Abfallbrennstoffen auch Rindenabfaelle, Holzschnitzel, Schilfgras und Sorghumpellets erfolgreich zur Brenngaserzeugung eingesetzt. Entsprechend den Anforderungen an das Produktgas und der Brennstoffqualitaet wird Luft, sauerstoffangereicherte Luft oder Sauerstoff/Dampfgemische als Vergasungsmittel im ZWS-Gaserzeuger eingesetzt. (orig)

  15. 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 heat...... of CSTR's and the size and number of CSTR's has been estimated from tracer experiments in an 80 MWth CFB boiler. It was not possible to evaluate the model against experimental data, but the dependence of particle size on the degree of devolatilization in the dense bed agrees qualitative with the expected...... behavior. The model shows that the devolatilization mainly occurs in the dense bed....

  16. 新型液固循环移动床反应器中直链烷基苯合成研究%Synthesis of linear alkylbenzene in a novel liquid-solid circulating moving bed reactor

    Institute of Scientific and Technical Information of China (English)

    韩明汉; 徐聪; 崔哲; 金涌

    2004-01-01

    For the alkylation of benzene with long-chain olefins,using Hβ zeolite catalyst as replacement of HF or AlCl3 has the advantages of no corrosion,less environmental pollution,and much more 2-phenyl isomer,which has the highest biodegradability and solubility,and better detergent properties among the related isomers.The characterization of the coke shows that the deactivation of catalyst is caused by the jam of bulkier molecules,such as naphthalene,indane and linear alkylbenzenes,which are too big to move quickly in the intracrystalline pores of catalyst.The deactivated catalyst can be regenerated by benzene washing at higher temperature.To make the processes of reaction and regeneration continuous,a novel moving bed reactor is developed.Comparing with the processes with fixed bed reactors,the processes in this work have the advantages of continuous operation,low temperature,low pressure,low mole ratio of benzene to olefins,and high weight hourly space velocity.

  17. Operation of fixed-bed chemical looping combustion

    NARCIS (Netherlands)

    Kimball, E.; Hamers, H.P.; Cobden, P.D.; Gallucci, F.; Sint Annaland, M. van

    2013-01-01

    Chemical Looping Combustion is an alternative technology for CO2 capture. While most systems utilize dual circulating fluidized-beds, this work shows that fixed-bed Chemical Looping Combustion is a feasible configuration for this technology. The inherent separation of the CO2 from the depleted air s

  18. Tests of Bed Agglomeration Tendency Using a Rotating Furnace; Roterugn foer bedoemning av sintringsbenaegenhet

    Energy Technology Data Exchange (ETDEWEB)

    Larfeldt, Jenny; Zintl, Frank [TPS Termiska Processer AB, Nykoeping (Sweden)

    2003-08-01

    Bed sintering is a well known problem in fluidised bed boilers. In order to avoid bed sintering the bed material turn over ratio is high which leads a high consumption of bed material. This work aims at developing and evaluating a method for testing the bed agglomeration tendency of a FB bed material by using a rotating furnace. A rotating furnace has been designed and tests have shown that three temperatures describing the increasing agglomeration tendency can be evaluated; TA when several particles stick to each other and to the crucible wall, TB when half of the material sticks to the wall and TC when almost all the material forms a ball in the crucible. Comparison with bed agglomeration tests has shown that TA is between 80 deg C to 130 deg C lower than the bed agglomeration temperature from fluid bed tests. It is shown that TB is closer to the bed agglomeration temperature and finally that the temperature TC is higher than the bed agglomeration temperature. It is concluded that in the rotating furnace sticking of particles is visualised early, and that this sticking will not cause defluidisation of the bed until more than half of the material in the crucible is sticky. Repeated tests has been performed at a heating rate of 5 deg/minute and a rotating speed of 12 rpm and a furnace inclination of 20 deg was found to give distinct results in the evaluation. The evaluation has shown to be reproducible at lower temperatures. At higher temperatures, around 1,000 deg C, the evaluation was complicated by a poor picture quality which probably can be improved by proper cooling of the camera. It has also been shown that sticking of material in the rotating furnace could be detected at relatively low temperatures of 750 deg C that disappeared at higher temperatures. This is likely to be explained by melting salts that evaporates as temperature increase. At even higher temperatures the sticking reappeared until a ball was formed in the crucible. The latter sticking is

  19. Study on the Mechanism of Competitive Adsorption of Circulating Fluidized Bed Ash and Cement to Poly Carboxylic Acid Water Reducing Agent%循环流化床灰对聚羧酸减水剂竞争吸附的影响研究

    Institute of Scientific and Technical Information of China (English)

    陈敏; 宋少民; 高霞

    2012-01-01

    In order to study on the effect of competitive adsorption of circulating fluidized bed ash and cement to poly carboxylic acid water reducing agent, by adding anhydrous sodium sulfate, dihydrate calcium sulphate and iron oxide into grade 11 fly ash to change the content of sulfur trioxide and iron oxide, its chemical composition close to circulating fluidized bed ash's is made, and the fuidity of cement past, zeta potential adding and concrete performance are tested. The results show that the dissolved sulfate and iron oxide in circulating fluidized bed ash have negative impact on adsorption of poly carboxylic acid water reducing agent. When the dosage of dissolved sulfate and iron oxide respectively reach 3% ,6% of the total cementing material,the corresponding paste both lost fluidity. Zeta potential tests indicate that the absolute of zeta potential gets smaller as the increase of dosage of dissolved sulfate and iron oxide, meanwhile repulsion between particles gets weaker, and dispersion becomes worse and dispersion system was more unstable. Concrete performance experiments show that the fluidity and compressive strength of concrete become smaller as sodium sulfate and iron oxide are incorporated in grade II fly ash, stump decreased from 220 mm to 125 mm, the highest strength reduce reached to 45%.%为研究循环流化床灰对聚羧酸减水剂竞争吸附的影响,通过在Ⅱ级粉煤灰中掺加无水硫酸纳、二水硫酸钙和氧化铁的方式来改变粉煤灰中三氧化硫和氧化铁含量,使其化学成分接近循环流化床灰,利用成分单因素分析的方法,测试减水剂水泥浆体的净浆流动度、Zeta电位和混凝土性能.研究结果表明循环流化床灰中的三氧化硫和氧化铁对聚羧酸减水剂的吸附有明显负面影响,当可溶性硫酸盐掺量达到胶凝材料的3%、氧化铁掺量达到6%时,相应浆体均失去流动性.Zeta电位试验表明随着无水硫酸钠和氧化铁掺

  20. Experimental investigation and mathematical modelling of the combustion of brown coal, refuse and mixed fuels in a circulating fluidized bed combustor; Experimentelle Untersuchung und mathematische Modellierung der Verbrennung von Braunkohle, Abfallstoffen und Mischbrennstoffen in einer zirkulierenden Wirbelschichtfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, W.; Brunne, T.; Hiller, A. [Technische Univ. Dresden (Germany). Inst. fuer Energietechnik; Albrecht, J. [Lurgi Umwelt GmbH, Frankfurt am Main (Germany); Quang, N. [Polytechnic Inst., Danang (Viet Nam)

    1998-09-01

    Extensive experiments on combustion of biological materials and residues in fluidized bed combustors and dust combustors have been carried out at the Department of Power Plant Engineering of Dresden University since the early nineties. Particular interest was taken in mixing brown coal with sewage sludge, sugar pulp and waste wood. The experiments were supplemented by modelling in a research project funded jointly by the BMBF and Messrs. Lurgi since early 1997. A combustion cell model designed by Siegen University is being modified for the new mixed fuels, and preliminary investigations were carried out on a batch reactor while the modelling work was continued. (orig.) [Deutsch] An dem Lehrstuhl fuer Kraftwerkstechnik der TU Dresden werden seit Anfang der 90-iger Jahre umfangreiche experimentelle Untersuchungen zur Verbrennung von Bio- und Reststoffen in Wirbelschicht- und Staubfeuerungen durchgefuehrt. Dabei war vor allem die Zufeuerung dieser Stoffe in Waermeerzeugeranlagen auf Braunkohlenbasis von besonderem Interesse. Experimentell konnte nachgewiesen werden, dass sowohl Biobrennstoffe als auch Abfaelle in zirkulierenden Wirbelschichtfeuerungen umweltschonend zur Waermeerzeugung eingesetzt werden koennen. Als Beispiel wird das an Hand von Braunkohle-Klaerschlammgemischen sowie Bagasse- und Holz-Braunkohlegemischen gezeigt. Neben den experimentellen Untersuchungen bietet die Modellierung der Verbrennungsvorgaenge ein geeignetes Mittel um Voraussagen zu anderen Mischungsanteilen sowie anderen geometrischen Abmessungen machen zu koennen. Seit Anfang 1997 wird dazu ein vom BMBF und der Firma Lurgi gefoerdertes Forschungsvorhaben bearbeitet. Ein von der Universitaet Gesamthochschule Siegen fuer die Braunkohleverbrennung konzipiertes Zellenmodell wird auf die neuen Brennstoffgemische erweitert. Da grundsaetzlich andere Stoffzusammensetzungen vorliegen, wurden an einem Batch-Reaktor Voruntersuchungen zum Pyrolyseverhalten der Brennstoffe durchgefuehrt. Erste

  1. Chemical Processes Related to Combustion in Fluidised Bed. Report for the period 2002-07-01 to 2004-06-30

    Energy Technology Data Exchange (ETDEWEB)

    Steenari, Britt-Marie; Lindqvist, Oliver [Chalmers University of Technology, Goeteborg (Sweden). Dep. of Environmental Inorganic Chemistry

    2005-02-01

    One part of the project was an investigation of the mechanism and kinetics of the absorption of potassium and cadmium in kaolin. Addition of kaolin has been suggested as a method to decrease problems like ash sintering, fouling and corrosion. The results showed that kaolin binds potassium effectively, especially if it is present as chloride or hydroxide. Reducing atmosphere and the presence of water vapour favours the absorption. The products are mainly silicates with low solubility. Cadmium is also absorbed by kaolin in a similar way. In the second part of the project, the chemical forms of some metals present in fly ash from combustion of MSW and bio fuels were studied. The most common Cd-compounds found were sulphate, oxide, chloride and silicate. It was also shown that Cd often is incorporated in calcium minerals, such as calcium silicates, CaO and CaC0{sub 3}, due to the fact that the ions Ca{sup 2+} and Cd{sup 2+} are almost similar in size and charge.

  2. Utilisation of forest chips, produced with different harvesting chains, in fluidised bed boilers of large power plants; Erilaisten korjuuketjujen tuottaman metsaehakkeen kaeyttoe suurten voimaloiden leijukerroskattiloissa - PUUT08

    Energy Technology Data Exchange (ETDEWEB)

    Orjala, M.; Ingalsuo, R. [VTT Energy, Jyvaeskylae (Finland)

    2001-07-01

    When combusting wood fuels the chemical composition of woof fuels can cause fouling and high-temperature corrosion of the heat transfer and superheater surfaces of the boiler. Problems are caused especially by forest chips, which include high quantities of needles and thin branches. Even though low alkali metal and chlorine contents are typical for wood fuels, the problem is that they are easily vaporised during combustion. Depending on the combustion conditions, the alkali metals can be oxidised to alkali metal oxides or they can form sulphates or chlorides. When combustion pure wood the sulphur content in combustion process is low and alkali metal compounds form chlorides easily, which can be condensed on the heat transfer surfaces of the boiler and form a significant high-temperature corrosion risk. If the sulphur content of the combustion process is increased e.g. by additional utilisation of peat, the chemistry of alkali metals is directed to formation of alkali metal sulphates instead of chlorides, and the chlorine liberated in the furnace forms gaseous hydrogen chloride (HCI). Hydrogen chloride, formed in combustion of wood fuels, is transferred in low concentrations in flue gases out of the boiler so it does not cause significant chlorine corrosion or emission risk. (orig.)

  3. Optical diagnostics study of air flow and powder fluidisation in Nexthaler®--Part I: Studies with lactose placebo formulation.

    Science.gov (United States)

    Pasquali, I; Merusi, C; Brambilla, G; Long, E J; Hargrave, G K; Versteeg, H K

    2015-12-30

    Effective drug delivery to the lungs by a DPI device requires the air-stream through the device to have sufficient power to aerosolise the powder. Furthermore, sufficient turbulence must be induced, along with particle-wall and particle-particle collisions, in order to de-aggregate small drug particles from large carrier particles. As a result, the emitted and the fine particle doses produced by many commercially available DPI devices tend to be strongly affected by the natural inter-patient variability of the inhaled air flow. The Nexthaler® is a multi-dose breath-actuated dry-powder inhaler with minimum drug delivery-flow rate dependency and incorporating a dose protector. The actuation mechanism of the dose-protector ensures that the dose is only exposed to the inhaled air flow if the flow has sufficient power to cause complete aerosolisation. For this study, a proprietary lactose placebo powder blend was filled into "transparent" Nexthaler® to allow application of high-speed imaging and particle image velocimetry (PIV) techniques to successfully interrogate and reveal details of the powder entrainment and emission processes coupled with characterisation of the flow environment in the vicinity of the mouthpiece exit. The study showed that fluidisation of the bulk of the powder occurs very quickly (∼20ms) after withdrawal of the dose protector followed by powder emission from the device within ∼50ms thereafter. The bulk of the metered placebo dose was emitted within 100-200ms. The visualisation study also revealed that a very small fraction of powder fines is emitted whilst the dose protector still covers the dosing cup as the flow rate through the device accelerates. The PIV results show that the flow exiting the device is highly turbulent with a rotating flow structure, which forces the particles to follow internal paths having a high probability of wall impacts, suggesting that the flow environment inside the Nexthaler® DPI will be very beneficial for

  4. Accounting Research of Nitrogen Oxide's Pollution Discharging Coefficient of Typical Circulating Fluidized Bed in Thermal Power Plant in Suzhou%苏州热电厂典型循环流化床氮氧化物排污系数核算研究

    Institute of Scientific and Technical Information of China (English)

    刘松华; 周静

    2014-01-01

    According to the current production status of thermal power plant's typical circulating fluidized bed in Suzhou and the situation of nitrogen oxide's discharge in 2013 ,the article uses the field measurement meth‐od to calculate the nitrogen oxide's pollution discharging coefficient of cogeneration industry in this area .In addition ,the article compares the coefficient with the recommended data from "The First National Census of Pollution Sources-the Handbook of Pollution Discharging Coefficient of Industrial Pollution Source" and analyzes the reason for the difference .%根据2013年苏州地区热电厂典型循环流化床企业生产现状及氮氧化物排放情况,采用实测法核算了该地区热电联产行业的氮氧化物排污系数,并将所得系数与《第一次全国污染源普查工业污染源产排污系数手册》推荐数据进行了对比,分析了差异原因。

  5. The Failure Mechanisms and Solutions of Anti-wear Thermal Spray Coatings for Solid Waste Incineration Circulating Fluidized Bed Boiler%垃圾焚烧循环流化床锅炉防磨热喷涂涂层失效机理及对策

    Institute of Scientific and Technical Information of China (English)

    胡金力; 陈国星; 黄科峰; 吴树辉; 盛洪产; 楼军; 章平衡; 薛猛

    2012-01-01

    本文分析了垃圾焚烧炉循环流化床(CFB)锅炉水冷壁管防磨热喷涂涂层的失效机理:S及碱金属等引起的S腐蚀导致涂层鼓泡,在炉内高温物料的磨损下涂层逐渐破损、剥落直至加速剥落失效。热喷涂防腐抗磨双效复合涂层能很好的解决了垃圾焚烧炉水冷壁同时存在的高温腐蚀和磨损的问题。%This paper analyzes the failure mechanisms of anti-wear thermal spray coatings on water wall tube of the wastes incineration Circulating Fluidized Bed (CFB) boiler. Sulfur corrosion caused by alkali, S and the Compound above lead to coatings bubbling, which are then gradually abraded by the high temperature flowing objects in the boiler. The coatings would be peeled off faster and faster once they are breaking. Composite thermal spray coatings of double-effect,corrosion, both abrasion resistant anticorrosive, is a good solution to high temperature corrosion and wear problems simultaneously.

  6. Requirements of the energy industry on fluidized-bed combustion equipment

    Energy Technology Data Exchange (ETDEWEB)

    Voigtlaender, P.; Weidlich, H.G.

    1984-12-01

    General technological advantages of low-grade brown coal combustion in fluidized-bed chambers are indicated. Brown coal with 7 to 9 MJ/kg calorific value and 25 to 35% dry ash content will be increasingly mined in the GDR. It is recommended that this fuel be used in fluidized-bed equipment, achieving high combustion efficiency with less pollution than in traditional grate combustion. A system with circulating fluidized-bed combustion is superior to a stationary atmospheric system. Combustion research will, therefore, focus on systems with circulating fluidized beds.

  7. Top Ten Bed Bug Tips

    Science.gov (United States)

    ... have bed bugs, not fleas, ticks or other insects. You can compare your insect to the pictures on our Identifying bed bugs ... bedbugs Bed Bugs Home Learn about Bed Bugs — Characteristics of Bed Bugs — Finding Bed Bugs Protecting Your ...

  8. The Low Temperature CFB Gasifier - Further Test Results and Possible Applications

    DEFF Research Database (Denmark)

    Stoholm, P.; Nielsen, Rasmus Glar; Sarbæk, L.;

    2002-01-01

    The novel "Low Temperature Circulating Fluidised Bed" (LT-CFB) gasification process is described together with the most recent results from the 50 kW LT-CFB test plant located at the Technical University of Denmark. The LT-CFB concept aims at avoiding problems due to ash sintering/agglomeration a...

  9. The Low Temperature CFB Gasifier

    DEFF Research Database (Denmark)

    Stoholm, P.; Nielsen, Rasmus Glar; Richardt, K.;

    2004-01-01

    The Low Temperature Circulating Fluidised Bed (LT-CFB) gasification process is described together with the 50 kW and the 500 kW test plants and latest test results. The LT-CFB process is especially developed for medium and large scale (few to >100 MW) gasification of problematic bio-fuels like st...

  10. Fluidized bed heat treating system

    Energy Technology Data Exchange (ETDEWEB)

    Ripley, Edward B; Pfennigwerth, Glenn L

    2014-05-06

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

  11. ECN contribution to the 10th European Conference 'Biomass for Energy and Industry'

    International Nuclear Information System (INIS)

    The titles of the six papers are: (1) Optimisation of Western European bioenergy and biomaterial strategies for greenhouse gas emission reduction in the 21st century; (2) Economically optimal production and allocation of biofuels for transport in the Netherlands; (3) Gasification of wood waste from public gardens for CHP production; (4) Circulating fluidized bed gasification experiments at ECN; (5) Bed-agglomeration in fluidisized-bed conversion of biomass; and (6) Combined production of chemicals and biomass with microalgae in a closed photobioreactor

  12. Bed In Summer

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In winter I get up at night And dress by yellow candle-light. In summer, quite the other way, I have to go to bed by day. I have to go to bed and see The birds still hopping on the tree, Or hear the grown-up people' s feet Still going past me in the stree

  13. Fluidized bed incinerator development

    International Nuclear Information System (INIS)

    A fluidized bed incinerator is being developed for burning rad contaminated solid and liquid waste materials. In situ neutralization of acid gases by the bed material, catalytic afterburning, and gas filtration are used to produce a clean flue gas without the use of aqueous scrubbing

  14. Fluidized bed calciner apparatus

    Science.gov (United States)

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

    1988-01-01

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

  15. 煤和垃圾衍生燃料循环流化床混烧的试验研究%Experimental Investigation on Co-firing of Coal and Refuse-derived Fuel in a Pilot-scale Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    柏继松; 余春江; 李廉明; 李兴亮; 王勤辉; 骆仲泱

    2012-01-01

    Co-firing of coal and refuse derived fuel(RDF) were investigated using a thermogravimetric analyzer(TGA) and a pilot-scale circulating fluidized bed combustor(CFB).Results obtained in TGA experiment show that,during co-firing process,coal and RDF can largely maintain their own combustion characteristics,while the addition of RDF significantly improve the combustion performance of coal.The CFB experiment shows that,compared to coal combustion,co-firing makes the axial temperature distribution more uniform;The addition of RDF reduce the CO,NO,N2O,SO2 emissions,but it greatly increase the HCl concentration in flue gas;The Ca-based materials contained in RDF can remove SO2 through sulfate reaction,while the presence of HCl promotes this kind of desulfurization reaction;During co-firing conditions,with the bed temperature increase,not only the conversion of fuel N/S/Cl to gas pollutants increase,but also the SO2 and HCl removal reactions by Ca-based substances are inhibited,therefore,the NO,SO2,HCl concentration in flue gas increase.%分别在热重分析仪和0.5MW循环流化床燃烧系统上进行了煤和垃圾衍生燃料混烧实验。热重试验表明:混烧过程中,两者基本上保持各自的燃烧特性,同时垃圾衍生燃料的加入能显著提高煤粉的燃烧性能。循环流化床试验表明:相对于煤粉单独燃烧,混烧能使整个炉膛的温度分布更均匀;垃圾衍生燃料的加入降低了CO、NO、N2O、SO2的排放,但却大大增加了烟气中HCl的浓度;垃圾衍生燃料中的钙基物质能对SO2起到脱除作用,同时HCl的存在会促进钙基物质与SO2的反应;在混烧情况下,随着床层温度的升高,N、S、Cl等元素对气相污染物的转化率增加,同时,钙基物质对酸性气体SO2、HCl的脱除反应受到抑制,因此烟气中的NO、SO2、HCl等污染物浓度增加。

  16. Bathing a patient in bed

    Science.gov (United States)

    Bed bath; Sponge bath ... Some patients cannot safely leave their beds to bathe. For these people, daily bed baths can help keep their skin healthy, control odor, and increase comfort. If moving the ...

  17. Bed-to-wall heat transfer in a downer reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lehner, P.; Wirth, K-E. [Erlangen-Nuremberg Univ., Lehrstuhl Mechanische Verfahrenstechnik, Erlangen (Germany)

    1999-04-01

    The effects of superficial gas velocity, solid circulating rate, suspension density and particle sizes on the bed-to-wall heat transfer coefficient have been determined in a downer reactor 3.5 m high , with an internal diameter of 0.1 m. Results showed an increase in the bed-to-wall heat transfer coefficient with increasing suspension density. The heat transfer coefficient by gas convection was found to play a significant role, especially at lower solid circulation rates or suspension densities and larger particle sizes. It was determined that at a given particle suspension density in the downer reactor, the heat transfer coefficient increase with decreasing particle size. A model was proposed to determine the bed-to-wall heat transfer coefficient in a downer reactor. 24 refs., 1 tab., 8 figs.

  18. Pressure Fluctuations as a Diagnostic Tool for Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-05-01

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

  19. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  20. Tapered bed bioreactor

    Science.gov (United States)

    Scott, Charles D.; Hancher, Charles W.

    1977-01-01

    A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

  1. Particle fuel bed tests

    International Nuclear Information System (INIS)

    Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H2 for 12 hours with no visible reaction or weight loss

  2. Enuresis (Bed-Wetting)

    Science.gov (United States)

    ... get out of bed to go to the bathroom. When do most children achieve bladder control? Children ... ask questions about your child's daytime and nighttime bathroom habits. Then your doctor will do a physical ...

  3. Bed rest and immunity

    Science.gov (United States)

    Sonnenfeld, Gerald; Aviles, Hernan; Butel, Janet S.; Shearer, William T.; Niesel, David; Pandya, Utpal; Allen, Christopher; Ochs, Hans D.; Blancher, Antoine; Abbal, Michel

    2007-02-01

    Space flight has been shown to result in altered immune responses. The current study was designed to investigate this possibility by using the bed rest model of some space flight conditions. A large number of women are included as subjects in the study. The hypothesis being tested is: 60 days head-down tilt bed rest of humans will affect the immune system and resistance to infection. Blood, urine and saliva samples will be obtained from bed rest subjects prior to, at intervals during, and after completion of 60 days of head-down tilt bed rest. Leukocyte blastogenesis, cytokine production and virus reactivation will be assessed. The ability of the subjects to respond appropriately to immunization with the neoantigen bacteriophage φX-174 will also be determined. Bed rest is being carried out at MEDES, Toulouse France, and the University of Texas Medical Branch, Galveston, TX. The studies to be carried out in France will also allow assessment of the effects of muscle/bone exercise and nutritional countermeasures on the immune system in addition to the effects of bed rest.

  4. Torrefaction of sawdust in a fluidized bed reactor.

    Science.gov (United States)

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

    2012-01-01

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

  5. Flow and combustion characteristics of a 2-dimensional spouted bed

    Science.gov (United States)

    Sawyer, R. F.; Hart, J. R.; Ohtake, K.

    1982-03-01

    A two dimensional spouted bed laboratory combustor was designed and constructed with the objective of studying the interaction among the gas flow, particle flow, and combustion. The facility, designed for a maximum thermal power of 20 kW, has a quartz front wall providing full optical access to particle flows and combustion processes. The combustor was characterized in terms of pressure, temperature, gas velocity, and particle velocity profiles and operating limits. Initial studies employed premixed propane and air and a fixed bed height, bed material, injector slot width, and combustor geometry. As in previous investigations of axisymmetric spouted beds, the ratio of particle mass circulation rate to jet mass flow rate was observed to be about ten. Combustion increased this ratio by about 10%. A pulsating mode of operation was noted with a characteristic frequency of about 10 Hz, controlled by the interaction of the particle and gas flows.

  6. 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

    major concern in thermal conversion of biomass encountered in fluidized beds is bed agglomeration, which may result in de-fluidization, leading to unscheduled downtime and additional costs. Biomass fuels, especially herbaceous plants, often contain significant amounts of silicon, potassium...... 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......-material samples undernon-oxidizing conditions in a bench-scale fluidized bed reactor set up. The de-fluidization studies involved measurements with sand and pure potassium salts (KCl and K2CO3) as well as with bed material samples obtained from a 6 MW Low Temperature Circulating Fluidized Bed (LTCFB) gasifier...

  7. Experimental study of gasification of herb residues of Ganmaoqingre granules in pilot-scale dual-loop circulating fluidized bed%感冒清热颗粒中药渣中试规模循环流化床气化实验

    Institute of Scientific and Technical Information of China (English)

    范鹏飞; 李景东; 刘艳涛; 董玉平; 梁敬翠; 盖超; 张彤辉

    2014-01-01

    The effect of properties of herb residue and air equivalence ratio on the gasification characteristics of Gangmaoqingre granules was investigated. Experiments were conducted in a pilot-scale dual-loop circulating fluidized bed. With the increase of water content,gasification temperature gradually decreased,the contents of tar and CO2 increased,while CO content and carbon conversion rate decreased. Besides,H2 content,gas calorific value and gasification efficiency increased first and then decreased. Smaller particle size contributed to lower tar content and gas calorific value. However,gas yield,gasification efficiency and carbon conversion increased gradually. With the decrease of particle size,H2,CH4,CO,CnHm contents and gasification temperature increased while CO2 content decreased. With the increase of air equivalence ratio,concentration of combustible gas, especially CO,gas calorific value and tar content gradually decreased. Besides,gasification temperature,gas yield and carbon conversion rate gradually increased. But gasification efficiency increased first and then decreased. When water content was smaller than 4% ,granularity was smaller than 4mm and air equivalence ratio was between 0.25 and 0.27,gasification efficiency would be higher,gasification result would be better.%以感冒清热颗粒中药渣为原料,在双回路循环流化床中试设备中进行热解气化实验,研究原料含水率、原料粒径以及空气当量比ER对其气化特性的影响。结果表明:①随着原料含水率的提高,炉内平均温度降低,产生的燃气中焦油含量、CO2含量明显提高;CO含量、气体产率、碳转化率显著降低;H2含量、燃气热值以及气化效率均呈现先增大后减小的趋势。②原料粒径越小,反应炉内平均温度越高,燃气中焦油含量越低,燃气热值和气体产率越高,气化效率以及碳转化率越高;H2、CH4、CO、CnHm含量增加,CO2含量减少。③随着ER的

  8. Fluidization characteristics of rice husk in a bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Leon, M.A. [Dalhousie Univ., Halifax, NS (Canada). Dept. of Mechanical Engineering; Dutta, A. [Nova Scotia Agricultural College, Truro, NS (Canada). Biomass Conversion and Biofuels

    2010-02-15

    Rice husk is made of 75 per cent volatile matter and 25 per cent ash. The ash contains nearly 90 per cent high-grade amorphous silica that can be recovered if it is burnt or gasified at low temperature in a fluidized bed. Amorphous silica is in demand for high-performance cement with low permeability and superior strength. However, sand is often added to the fluidized bed to prevent slugging. The resulting husk-ash mixed with sand is a useless disposal burden that cannot be used in any applications. This study demonstrated how to fluidize rice husk in a wide bed without the presence of another granular solid such as sand. Experimental results from a circulating fluidized bed showed that bed cross-section has an important influence on the fluidization characteristics of rice husk. As the cross-section increases, it becomes easier to fluidize the husk without slugging. Particle size, sphericity, bulk density, and transport velocity of husk were measured in this study. The riser was operated under bubbling bed regimes. The minimum fluidization velocity was measured under different bed depths and cross-sections. The study confirmed that rice husk fluidized in a bed of sand can be kept in a pseudo fluidized state without mixing it with granular solid particles if the bed is large enough to avoid slug formation. The pseudo bubbling fluidized state is characterized by many micro-channels that constantly form and dissolve. The addition of smooth fine sand particles reduces the inter-particle friction, resulting in better bed fluidizing at lower gas velocity. 12 refs., 2 tabs., 5 figs.

  9. Mountains and Tropical Circulation

    Science.gov (United States)

    Naiman, Z.; Goodman, P. J.; Krasting, J. P.; Malyshev, S.; Russell, J. L.; Stouffer, R. J.

    2015-12-01

    Observed tropical convection exhibits zonal asymmetries that strongly influence spatial precipitation patterns. The drivers of changes to this zonally-asymmetric Walker circulation on decadal and longer timescales have been the focus of significant recent research. Here we use two state-of-the-art earth system models to explore the impact of earth's mountains on the Walker circulation. When all land-surface topography is removed, the Walker circulation weakens by 33-59%. There is a ~30% decrease in global, large-scale upward vertical wind velocities in the middle of the troposphere, but only minor changes in global average convective mass flux, precipitation, surface and sea-surface temperatures. The zonally symmetric Hadley circulation is also largely unchanged. Following the spatial pattern of changes to large-scale vertical wind velocities, precipitation becomes less focused over the tropics. The weakening of the Walker circulation, but not the Hadley circulation, is similar to the behavior of climate models during radiative forcing experiments: in our simulations, the weakening is associated with changes in vertical wind velocities, rather than the hydrologic cycle. These results indicate suggest that mountain heights may significantly influence the Walker circulation on geologic time scales, and observed changes in tropical precipitation over millions of years may have been forced by changes in tropical orography.

  10. 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...... bed gasifier can be successfully predicted by applying neural networks. ANNs models use in the input layer the biomass composition and few operating parameters, two neurons in the hidden layer and the backpropagation algorithm. The results obtained by these ANNs show high agreement with published...

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.

    1999-07-01

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

  12. Bed bug deterrence

    Directory of Open Access Journals (Sweden)

    Haynes Kenneth F

    2010-09-01

    Full Text Available Abstract A recent study in BMC Biology has determined that the immature stage of the bed bug (the nymph signals its reproductive status to adult males using pheromones and thus avoids the trauma associated with copulation in this species. The success of this nymphal strategy of deterrence is instructive. Against the background of increasing problems with bed bugs, this research raises the question whether pheromones might be used to control them. See research article http://www.biomedcentral.com/1741-7007/8/121

  13. in Spouted Bed

    Directory of Open Access Journals (Sweden)

    Bronislaw Buczek

    2013-01-01

    Full Text Available Samples of active coke, fresh and spent after cleaning flue gases from communal waste incinerators, were investigated. The outer layers of both coke particles were separately removed by comminution in a spouted bed. The samples of both active cokes were analysed by means of densities, mercury porosimetry, and adsorption technique. Remaining cores were examined to determine the degree of consumption of coke by the sorption of hazardous emissions (SO2, HCl, and heavy metals through its bed. Differences in contamination levels within the porous structure of the particles were estimated. The study demonstrated the effectiveness of commercial active coke in the cleaning of flue gases.

  14. The impact of bed temperature on heat transfer characteristic between fluidized bed and vertical rifled tubes

    Science.gov (United States)

    Blaszczuk, Artur; Nowak, Wojciech

    2016-10-01

    In the present work, the heat transfer study focuses on assessment of the impact of bed temperature on the local heat transfer characteristic between a fluidized bed and vertical rifled tubes (38mm-O.D.) in a commercial circulating fluidized bed (CFB) boiler. Heat transfer behavior in a 1296t/h supercritical CFB furnace has been analyzed for Geldart B particle with Sauter mean diameter of 0.219 and 0.246mm. The heat transfer experiments were conducted for the active heat transfer surface in the form of membrane tube with a longitudinal fin at the tube crest under the normal operating conditions of CFB boiler. A heat transfer analysis of CFB boiler with detailed consideration of the bed-to-wall heat transfer coefficient and the contribution of heat transfer mechanisms inside furnace chamber were investigated using mechanistic heat transfer model based on cluster renewal approach. The predicted values of heat transfer coefficient are compared with empirical correlation for CFB units in large-scale.

  15. Maximum spoutable bed height of spout-fluid bed

    Energy Technology Data Exchange (ETDEWEB)

    Wenqi Zhong; Mingyao Zhang; Baosheng Jin [Southeast University, Nanjing (China). Key Laboratory on Clean Coal Power Generation and Combustion Technology of Ministry of Education

    2006-11-15

    Experimental study on the maximum spoutable bed height of a spout-fluid bed (cross-section of 0.3 m x 0.03 m and height of 2 m) packed with Geldart group D particles has been carried out. The effects of particle size, spout nozzle size and fluidizing gas flow rate on the maximum spoutable bed height were studied. Experimental data were compared to some published experiments and predictions. The results show that the maximum spoutable bed height of spout-fluid bed decreases with increasing particle size and spout nozzle size, which appears the same trend to that of spouted beds. The increasing of fluidizing gas flow rate leads to a sharply decrease in the maximum spoutable bed height. The existent correlations of the maximum spoutable bed height in the literature were observed to involve large discrepancies. Additionally, the flow characteristics when bed materials deeper than the maximum spoutable height were summarized. Under this condition, the spout-fluid bed operated without a stable and coherent spout or fountain assembles the characteristics of jetting fluidized bed. Besides, the mechanisms of spout termination were investigated. It was found that slugging in the spout and growth of instabilities would cause the spout termination in spout-fluid bed.

  16. Getting Rid of Bed Bugs

    Science.gov (United States)

    ... how you select a company. Related Information Collaborative Strategy on Bed Bugs - highlights ways that all levels of government, community, academia and private industry can work together to reduce bed bugs across ...

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

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaoliang; HE Rong; Toshiyuki Suda; Junichi Sato

    2007-01-01

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

  18. Gaussian Fibonacci Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices have become important tools in solving integrable system, Hamiltonian structure, and integral equations. In this paper, we prove that Gaussian Fibonacci circulant type matrices are invertible matrices for n>2 and give the explicit determinants and the inverse matrices. Furthermore, the upper bounds for the spread on Gaussian Fibonacci circulant and left circulant matrices are presented, respectively.

  19. Automation of a fixed-bed continuous–flow reactor

    OpenAIRE

    Alcántara, R.; Canoira, L.; R. Conde; Fernández-Sánchez, J. M.; Navarro, A.

    1994-01-01

    This paper describes the design and operation of a laboratory plant with a fixed-bed continuous-flow reactor, fully automated and controlled from a personal computer. The automated variables include two gas flows, one liquid flow, six temperatures, two pressures, one circulation of a cooling liquid, and 10 electrovalves. An adaptive-predictive control system was used. The chemical process chosen to run the automated reactor was the conversion of methanol to gasoline over a ZSM-5 catalyst. Thi...

  20. Geomechanics of bedded salt

    Energy Technology Data Exchange (ETDEWEB)

    Serata, S.; Milnor, S.W.

    1979-06-08

    Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temperature is considered. Findings on the permeability of salt are summarized, and the in-situ behavior of openings in bedded salt is described based on extensive engineering experience. A stress measuring system utilizing a finite element computer code is discussed. Geological factors affecting the stability of salt openings are considered, and the Stress Control Technique for designing stable openings in bedded salt formations is explained.

  1. Geomechanics of bedded salt

    International Nuclear Information System (INIS)

    Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temperature is considered. Findings on the permeability of salt are summarized, and the in-situ behavior of openings in bedded salt is described based on extensive engineering experience. A stress measuring system utilizing a finite element computer code is discussed. Geological factors affecting the stability of salt openings are considered, and the Stress Control Technique for designing stable openings in bedded salt formations is explained

  2. Circulant Double Coverings of a Circulant Graph of Valency Five

    Institute of Scientific and Technical Information of China (English)

    Rong Quan FENG; Jin Ho KWAK

    2007-01-01

    Enumerating the isomorphism classes of several types of graph covering projections is one of the central research topics in enumerative topological graph theory. A covering of G is called circulant if its covering graph is circulant. Recently, the authors [Discrete Math., 277, 73-85 (2004)]enumerated the isomorphism classes of circulant double coverings of a certain type, called a typicalcovering, and showed that no double covering of a circulant graph of valency three is circulant. Also, in [Graphs and Combinatorics, 21, 386-400 (2005)], the isomorphism classes of circulant double coverings of a circulant graph of valency four are enumerated. In this paper, the isomorphism classes of circulant double coverings of a circulant graph of valency five are enumerated.

  3. PULMONARY CIRCULATION AT EXERCISE

    OpenAIRE

    R. Naeije; CHESLER, N

    2012-01-01

    The pulmonary circulation is a high flow and low pressure circuit, with an average resistance of 1 mmHg.min.L−1 in young adults, increasing to 2.5 mmHg.min.L−1 over 4–6 decades of life. Pulmonary vascular mechanics at exercise are best described by distensible models. Exercise does not appear to affect the time constant of the pulmonary circulation or the longitudinal distribution of resistances. Very high flows are associated with high capillary pressures, up to a 20–25 mmHg threshold associ...

  4. Formation and displacement of bubbles in a packed bed

    CERN Document Server

    Soto, Enrique; Zenit, Roberto

    2010-01-01

    The fluid dynamics video show a gas stream which is injected into a packed bed immersed in water and fluid dynamcis video present the dynamics involved. The refractive index of the water an the packed bed are quite similar and the edges of the spherical particles can be seen. Two distinctive regimens can be observed. The first one, for low air flow rates, which is characterized by the percolation of the air thought the interstitial space among particles. And the second one, for high air flow rates, which is characterized by the accumulation of air inside the packed bed without percolation, it can be observed that the bubble pull apart the particles apart. Furthermore, for the first case the position of the particles remains constant while for the second one a circulation of particles is induced by the bubbles flow.

  5. 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...... is estimated from experiments under stable operating conditions with constant bed inventory, reactor temperature and exit CO2 concentration. The validated CFB carbonator model was used to simulate different operating conditions relevant for CO2 capture from a power plant and from a cement plant. The results...... show that particle recirculation rates of 2-5 kg/(m2s) or ratio of bed inventory to recirculation rates of 70-176 s are sufficient for attaining 90% CO2 capture efficiency depending on the inlet Ca to C ratio. © 2014 American Chemical Society....

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

    Directory of Open Access Journals (Sweden)

    Nurdil Eskin

    2005-09-01

    Full Text Available In this study, effects of the different types of heat exchanger surfaces on the second law efficiency of a small-scale circulating fluidized bed (CFB combustor are analyzed and the results are compared with the bubbling fluidized bed coal combustor effectiveness values. Using a previously developed simulation program, combustor efficiency and entropy generation values are obtained at different operation velocities at different height and volume ratios of the immersed surfaces, both for circulating and bubbling fluidized bed combustors. Besides that, the influence of the immersed surface types on the combustor efficiency was compared for different fluidized bed combustors. Through this analysis, the dimensions, arrangement and type of the immersed surfaces which achieve maximum efficiency are obtained.

  7. Simulating the Dynamics of Spouted-Bed Nuclear Fuel Coaters

    Energy Technology Data Exchange (ETDEWEB)

    Pannala, Sreekanth [ORNL; Daw, C Stuart [ORNL; FINNEY, Charles E A [ORNL; Boyalakuntla, Dhanunjay S [ORNL; Syamlal, M [National Energy Technology Laboratory (NETL); O' Brien, T. J. [National Energy Technology Laboratory (NETL)

    2007-01-01

    We describe simulation studies of the dynamics of spouted beds used for CVD coating of nuclear fuel particles. Our principal modeling tool is the Multiphase Flow with Interphase eXchanges (MFIX) code that was originally developed by the National Energy Technology Laboratory (NETL) for fossil energy process applications. In addition to standard MFIX features that allow coupling of transient hydrodynamics, heat and mass transfer, and chemical kinetics, we employ special post-processing tools to track particle mixing and circulation as functions of operating conditions and bed design. We describe in detail one major feature of the dynamics, which is the occurrence of very regular spontaneous pulsations of gas and particle flow in the spout. These pulsations appear to be critically linked to the entrainment and circulation of solids, and they produce readily accessible dynamic pressure variations that can be used for direct comparisons of model predictions with experiments. Spouted-bed dynamics are important from a CVD perspective because they directly determine the magnitude and variability of the concentration and species gradients in the zone where reactant gases first come into contact with hot particles. As this unsteady spouted-bed environment differs from other types of CVD reactors, the design and scale-up of such reactors is likely to involve unique modeling issues. Our primary goal here is to lay the groundwork for how computational simulation can be used to address these modeling issues in the specific context of nuclear fuel particle coating.

  8. Simulating the dynamics of spouted-bed nuclear fuel coaters

    Energy Technology Data Exchange (ETDEWEB)

    Pannala, S.; Daw, C.S.; Finney, C.E.A.; Boyalakuntla, D. [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Syamlal, M.; O' Brien, T.J. [National Energy Technology Laboratory, Morgantown, WV, 26505 (United States)

    2007-09-15

    We describe simulation studies of the dynamics of spouted beds used for CVD coating of nuclear fuel particles. Our principal modeling tool is the Multiphase Flow with Interphase eXchanges (MFIX) code that was originally developed by the National Energy Technology Laboratory (NETL) for fossil energy process applications. In addition to standard MFIX features that allow coupling of transient hydrodynamics, heat and mass transfer, and chemical kinetics, we employ special post-processing tools to track particle mixing and circulation as functions of operating conditions and bed design. We describe in detail one major feature of the dynamics, which is the occurrence of very regular spontaneous pulsations of gas and particle flow in the spout. These pulsations appear to be critically linked to the entrainment and circulation of solids, and they produce readily accessible dynamic pressure variations that can be used for direct comparisons of model predictions with experiments. Spouted-bed dynamics are important from a CVD perspective because they directly determine the magnitude and variability of the concentration and species gradients in the zone where reactant gases first come into contact with hot particles. As this unsteady spouted-bed environment differs from other types of CVD reactors, the design and scale-up of such reactors is likely to involve unique modeling issues. Our primary goal here is to lay the groundwork for how computational simulation can be used to address these modeling issues in the specific context of nuclear fuel particle coating. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  9. Cardiovascular studies in the rhesus monkey. [brain circulation during stress

    Science.gov (United States)

    Stone, H. L.; Sandler, H.

    1977-01-01

    Criteria are given for selecting the macaca mulatta as the analogue of the human in the study of cerebral circulation, particularly the control of the cerebral vascular bed during normal and stressful conditions. Topics discussed include surgical preparation of subject; responses to changes in arterial pressure, oxygen, and carbon dioxide; innervation of cerebral vessels; cerebral flow response to acceleration; and cerebral blood flow and cerebellar stimulation.

  10. Bed mixing dryer for high moisture content fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hulkkonen, S.; Heinonen, O. [Imatran Voima Oy, Vantaa (Finland)

    1997-12-31

    Bed mixing dryer is a new type of fuel drying technology for fluidized bed combustion. The idea is to extract hot bed material from the fluidized bed and use it as a heat source for drying the fuel. Drying occurs at steam atmosphere which makes it possible to recover the latent heat of evaporation to process. This improves the thermal efficiency of the power plant process considerably, especially in combined heat and power applications. Imatran Voima Oy (IVO) has developed the Bed Mixing Dryer technology since early 1990s. The first pilot plant was built in 1994 to IVO`s Kuusamo peat and wood fired power plant. The capacity of the plant is 6 MW{sub e} and 20 MW of district heat. In Kuusamo the dryer is connected to a bubbling fluidized bed. Since it`s commissioning the dryer has been used successfully for about 3000 hours during the heating season in wintertime. The second application of the technology will be a demonstration project in Oerebro (S). IVO Power Engineering Ltd will supply in 1997 a dryer to Oerebro Energi`s peat, wood and coal fired CHP plant equipped with circulating fluidized bed boiler. The fuel to be dried is sawdust with fuel input of about 60 MW. In Kuusamo the dryer produces 3 MW of additional district heat and in Oerebro 6 MW. The fuels in Kuusamo are peat, saw dust and bark. In addition to the municipal heat production this type of drying technology has its benefits in pulp and paper industry processes. Disposal of paper mill sludges is becoming more difficult and costly which has resulted in need of alternative treatment. Drying of the sludge before combustion in a boiler for power production is an attractive option. At the moment IVO is carrying out several studies to apply the Bed Mixing Dryer in pulp and paper industry processes. Economy of drying the sludge looks promising

  11. A study of the fluid dynamics of the spouted bed using CFD

    OpenAIRE

    C. R. Duarte; V. V. Murata; M. A. S. Barrozo

    2005-01-01

    The spouted bed has been used in drying, granulation, catalytic polymerization, residue treatment and coating of several materials. Its success is attributed to its solids circulation characteristics and excellent gas-particle contact. In this work the pattern of solids and gas flows in a spouted bed was numerically simulated using a Eulerian multiphase model. The computational work was significantly reduced for axisymmetric gas-solids flows. The simulated velocity and voidage profiles were c...

  12. Experimental Study on Coal Multi-generation in Dual Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    Fan Xiaoxu; Lu Qinggang; Na Yongjie; Liu Qi

    2007-01-01

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

  13. Bed Rest Muscular Atrophy

    Science.gov (United States)

    Greenleaf, John E.

    2000-01-01

    A major debilitating response from prolonged bed rest (BR) is muscle atrophy, defined as a "decrease in size of a part of tissue after full development has been attained: a wasting away of tissue as from disuse, old age, injury or disease". Part of the complicated mechanism for the dizziness, increased body instability, and exaggerated gait in patients who arise immediately after BR may be a result of not only foot pain, but also of muscular atrophy and associated reduction in lower limb strength. Also, there seems to be a close association between muscle atrophy and bone atrophy. A discussion of many facets of the total BR homeostatic syndrome has been published. The old adage that use determines form which promotes function of bone (Wolff's law) also applies to those people exposed to prolonged BR (without exercise training) in whom muscle atrophy is a consistent finding. An extreme case involved a 16-year-old boy who was ordered to bed by his mother in 1932: after 50 years in bed he had "a lily-white frame with limbs as thin as the legs of a ladder-back chair". These findings emphasize the close relationship between muscle atrophy and bone atrophy. In addition to loss of muscle mass during deconditioning, there is a significant loss of muscle strength and a decrease in protein synthesis. Because the decreases in force (strength) are proportionately greater than those in fiber size or muscle cross-sectional area, other contributory factors must be involved; muscle fiber dehydration may be important.

  14. Coal Bed Methane Primer

    Energy Technology Data Exchange (ETDEWEB)

    Dan Arthur; Bruce Langhus; Jon Seekins

    2005-05-25

    During the second half of the 1990's Coal Bed Methane (CBM) production increased dramatically nationwide to represent a significant new source of income and natural gas for many independent and established producers. Matching these soaring production rates during this period was a heightened public awareness of environmental concerns. These concerns left unexplained and under-addressed have created a significant growth in public involvement generating literally thousands of unfocused project comments for various regional NEPA efforts resulting in the delayed development of public and fee lands. The accelerating interest in CBM development coupled to the growth in public involvement has prompted the conceptualization of this project for the development of a CBM Primer. The Primer is designed to serve as a summary document, which introduces and encapsulates information pertinent to the development of Coal Bed Methane (CBM), including focused discussions of coal deposits, methane as a natural formed gas, split mineral estates, development techniques, operational issues, producing methods, applicable regulatory frameworks, land and resource management, mitigation measures, preparation of project plans, data availability, Indian Trust issues and relevant environmental technologies. An important aspect of gaining access to federal, state, tribal, or fee lands involves education of a broad array of stakeholders, including land and mineral owners, regulators, conservationists, tribal governments, special interest groups, and numerous others that could be impacted by the development of coal bed methane. Perhaps the most crucial aspect of successfully developing CBM resources is stakeholder education. Currently, an inconsistent picture of CBM exists. There is a significant lack of understanding on the parts of nearly all stakeholders, including industry, government, special interest groups, and land owners. It is envisioned the Primer would being used by a variety of

  15. Fluid bed solids heater. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Preuit, L. C.

    1980-01-01

    A solids heater which operates at up to 2000 F was designed, fabricated, installed and operated through checkout at the Morgantown Energy Technology Center at Morgantown, West Virginia. The system, designated the 2000 F Fluid Bed Solids Heater (FBSH) uses a fluidized bed to heat limestone to 600 F and aluminium oxide or silicon carbide to 2000 F and discharges heated solids upon demand. The FBSH with added valve handling and pressurization equipment is known as the Valve Hot Solids Test Unit and is intended for use by the US Department of Energy for testing of valves for severe service applications in coal conversion and utilization processes. The FBSH as designed and supplied by Combustion Power Company includes process equipment, controls, the enclosing building and other associated equipment. In the 600 F range of operation it can circulate limestone through two valve test trains simultaneously on a continuous basis. Only one valve test train is used for 2000 F solids and operation in that range is also continuous. Limestone, crushed to minus 5/16 size, is heated, discharged, and recycled at a maximum average rate of 250 lb/min while aluminum oxide or silicon carbide, No. 8 grit, is circulated at rates up to 167 lb/min. The FBSH control system is designed for automatic operation, and capability is included for external computerized data acquisition and/or supervisory control. An operating and maintenance manual and as-built drawings have been submitted. This report describes the FBSH equipment, its design basis, and its operation. It has been prepared and submitted in fulfillment of Contract Number DIAC05-77ET10499.

  16. 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.)

  17. 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)

  18. INTERNAL CIRCULATION ENVELOPES

    CERN Multimedia

    Mail Office

    2001-01-01

    Internal mail envelopes often finish up in large piles in certain offices, thus creating a shortage for other users of the mail service, who would be grateful if everyone with an unused stock could deposit them in their mail box, after attaching them together with an elastic band or a piece of string. The messengers will then collect them so that the Mail Office can put them back in circulation. Thank you for your understanding and collaboration.

  19. Dryout heat flux and flooding phenomena in debris beds consisting of homogeneous diameter particles

    International Nuclear Information System (INIS)

    Since the TMI-2 accident, which occurred in 1979, necessity of understanding phenomena associated with a severe accident have been recognized and researches have been conducted in many countries. During a severe accident of a light water reactor, a debris bed consisting of the degraded core materials would be formed. Because the debris bed continues to release decay heat, the debris bed would remelt when the coolable geometry is not maintained. Thus the degraded core coolability experiments to investigate the influence of the debris particle diameter and coolant flow conditions on the coolability of the debris bed and the flooding experiments to investigate the dependence of flooding phenomena on the configuration of the debris bed have been conducted in JAERI. From the degraded core coolability experiments, the following conclusions were derived; the coolability of debris beds would be improved by coolant supply into the beds, Lipinski's 1-dimensional model shows good agreement with the measured dryout heat flux for the beds under stagnant and forced flow conditions from the bottom of the beds, and the analytical model used for the case that coolant is fed by natural circulation through the downcomer reproduces the experimental results. And the following conclusions were given from the flooding experiments ; no dependence between bed height and the flooding constant exists for the beds lower than the critical bed height, flooding phenomena of the stratified beds would be dominated by the layer consisting of smaller particles, and the predicted dryout heat flux by the analytical model based on the flooding theory gives underestimation under stagnant condition. (author)

  20. Lightweight Magnetic Cooler With a Reversible Circulator

    Science.gov (United States)

    Chen, Weibo; McCormick, John

    2011-01-01

    A design of a highly efficient and lightweight space magnetic cooler has been developed that can continuously provide remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. The innovative design uses a cryogenic circulator that enables the cooler to operate at a high cycle frequency to achieve a large cooling capacity. The ability to provide remote/distributed cooling not only allows flexible integration with a payload and spacecraft, but also reduces the mass of the magnetic shields needed. The active magnetic regenerative refrigerator (AMRR) system is shown in the figure. This design mainly consists of two identical magnetic regenerators surrounded by their superconducting magnets and a reversible circulator. Each regenerator also has a heat exchanger at its warm end to reject the magnetization heat to the heat sink, and the two regenerators share a cold-end heat exchanger to absorb heat from a cooling target. The circulator controls the flow direction, which cycles in concert with the magnetic fields, to facilitate heat transfer. Helium enters the hot end of the demagnetized column, is cooled by the refrigerant, and passes into the cold-end heat exchanger to absorb heat. The helium then enters the cold end of the magnetized column, absorbing heat from the refrigerant, and enters the hot-end heat exchanger to reject the magnetization heat. The efficient heat transfer in the AMRR allows the system to operate at a relatively short cycle period to achieve a large cooling power. The key mechanical components in the magnetic cooler are the reversible circulator and the magnetic regenerators. The circulator uses non-contacting, self-acting gas bearings and clearance seals to achieve long life and vibration- free operation. There are no valves or mechanical wear in this circulator, so the reliability is predicted to be very high. The magnetic regenerator employs a structured bed configuration. The core consists of a stack of thin

  1. The effect of lateral flooding on the coolability of irregular core debris beds

    Energy Technology Data Exchange (ETDEWEB)

    Takasuo, Eveliina, E-mail: eveliina.takasuo@vtt.f [VTT Technical Research Centre of Finland (Finland); Holmstroem, Stefan; Kinnunen, Tuomo; Pankakoski, Pekka H.; Hosio, Ensio; Lindholm, Ilona [VTT Technical Research Centre of Finland (Finland)

    2011-04-15

    The coolability of ex-vessel core debris is an important issue in the severe accident management strategy of, e.g. the Nordic boiling water reactors. In a core melt accident, the molten core material is expected to discharge into the containment and form a porous debris bed on the pedestal floor of a flooded lower drywell. The debris bed generates decay heat which must be removed by boiling in order to stabilize the debris bed and to prevent local dryout and possible re-melting of the material. The STYX test facility which consists of a cylindrical bed of irregular alumina particles has been used to investigate the effect of lateral coolant inflow on the dryout heat flux of the particle bed. The lateral flow was achieved by downcomers attached on the sides of the test rig. The downcomers provide coolant into the lower region of the bed by natural circulation. Both homogenous and stratified bed configurations have been examined. It was observed that the dryout heat flux is increased by 22-25% for the homogenous test bed compared to the case with no lateral flooding. For the stratified configuration with a fine particle layer on top of the bed, no significant increase in the dryout heat flux was observed. The experiments have been analyzed by using the MEWA-2D code. Models which include explicit consideration of gas-liquid friction were used in the calculations in order to realistically capture the lateral flow configuration.

  2. The effect of lateral flooding on the coolability of irregular core debris beds

    International Nuclear Information System (INIS)

    The coolability of ex-vessel core debris is an important issue in the severe accident management strategy of, e.g. the Nordic boiling water reactors. In a core melt accident, the molten core material is expected to discharge into the containment and form a porous debris bed on the pedestal floor of a flooded lower drywell. The debris bed generates decay heat which must be removed by boiling in order to stabilize the debris bed and to prevent local dryout and possible re-melting of the material. The STYX test facility which consists of a cylindrical bed of irregular alumina particles has been used to investigate the effect of lateral coolant inflow on the dryout heat flux of the particle bed. The lateral flow was achieved by downcomers attached on the sides of the test rig. The downcomers provide coolant into the lower region of the bed by natural circulation. Both homogenous and stratified bed configurations have been examined. It was observed that the dryout heat flux is increased by 22-25% for the homogenous test bed compared to the case with no lateral flooding. For the stratified configuration with a fine particle layer on top of the bed, no significant increase in the dryout heat flux was observed. The experiments have been analyzed by using the MEWA-2D code. Models which include explicit consideration of gas-liquid friction were used in the calculations in order to realistically capture the lateral flow configuration.

  3. Contributions ECN biomass to 'Developments in thermochemical biomass conversion' conference. 17-22 September 2000, Tyrol, Austria

    Energy Technology Data Exchange (ETDEWEB)

    Boerrigter, H.; Daey Ouwens, C.; Van Doorn, J.; Van der Drift, A.; Hofmans, H.; Huijnen, H.; Kersten, S.R.A.; Kiel, J.H.A.; Moonen, R.H.W.; Mozaffarian, M.; Neeft, J.P.A.; Oosting, T.P.; Den Uil, H.; Visser, H.J.M.; Zwart, R.W.R. [ECN , Biomass, Petten (Netherlands)

    2000-07-01

    This report contains the contributions (7) of the business unit ECN Biomass of the Netherlands Energy Research Foundation (ECN) in Petten, Netherlands, to the title conference. Separate abstracts were prepared for each of the seven papers: (1) Effect of fuel size and process temperature on fuel gas quality from CFB gasification of biomass; (2) Gas mixing in a pilot scale (500 KW{sub th}) air blown circulating fluidised bed biomass gasifier; (3) Guideline for sampling and analysis of 'tars' and particles in biomass producer gases; (4) Biomass ash - bed material interactions leading to agglomeration in fluidised bed combustion and gasification; (5) Production of substitute natural gas by biomass hydrogasification; (6) CASST. A new and advanced process for biomass gasification; and (7) New developments in the field of tri-generation from biomass and waste. A survey.

  4. LSP Composite Test Bed Design

    Science.gov (United States)

    Day, Arthur C.; Griess, Kenneth H.

    2013-01-01

    This document provides standalone information for the Lightning Strike Protection (LSP) Composite Substrate Test Bed Design. A six-sheet drawing set is reproduced for reference, as is some additional descriptive information on suitable sensors and use of the test bed.

  5. Modelled Circulation In Storfjorden

    Science.gov (United States)

    Skogseth, R.; Asplin, L.

    The model area Storfjorden is situated between the islands Spitsbergen, Barentsöya and Edgeöya at the Svalbard Archipelago. The entrance of Storfjorden is defined by a shallow bank Storfjordbanken and some small islands Tusenöyane in southeast, and by an 115m deep sill at about 76 45' N in the south. Maximum depth in Storfjorden is 190m, which is surrounded by gradually shallower shelves in the north, the east and southeast. A steep bottom slope is present on the western side of Storfjorden. He- leysundet and Freemansundet, two sounds between respectively Spitsbergen and Bar- entsöya, and Barentsöya and Edgeöya, define two narrow and shallow entrances in the north and northeast connecting Storfjorden with the northwestern Barents Sea. Strong tidal currents exist in Heleysundet (4-5ms-1) and Freemansundet (2-3ms-1), but the general circulation in Storfjorden is not well known. The coastal current in Storfjor- den is cyclonic directed into Storfjorden south of Edgeöya from the East Spitsbergen Current and out of Storfjorden south of Spitsbergen where it is called Sørkappstrøm- men. A three-dimensional sigma layered numerical ocean model called Bergen Ocean Model (BOM) was used to simulate the circulation in Storfjorden with Freemansundet opened. Two simulations were carried out, one with heat flux (100 Wm-2) and one without heat flux from the ocean to the atmosphere. The heat flux was applied only in the proper fjord area north of the sill and not outside as a crude approximation of the effects of a polynya in the sea ice cover during winter. Both simulations had a 4km horizontal resolution and 21 sigma layers. The model is forced by winds (from the NCEP reanalyzed fields) and tides. Initial fields are from the DNMI/IMR climatol- ogy. The model simulation without heat flux gave a circulation heavily dependent on tidal forcing, showing strong tidal currents up to 2ms-1 in Freemansundet, between Tusenöyane and on Storfjordbanken southwest of Edgeöya. Earlier

  6. Resolvability in Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    Muhammad SALMAN; Imran JAVAID; Muhammad Anwar CHAUDHRY

    2012-01-01

    A set W of the vertices of a connected graph G is called a resolving set for G if for every two distinct vertices u,v ∈ V(G) there is a vertex w ∈ W such that d(u,w) ≠ d(v,w).A resolving set of minimum cardinality is called a metric basis for G and the number of vertices in a metric basis is called the metric dimension of G,denoted by dim(G).For a vertex u of G and a subset S of V(G),the distance between u and S is the number mins∈s d(u,s).A k-partition H ={S1,S2,...,Sk} of V(G) is called a resolving partition if for every two distinct vertices u,v ∈ V(G) there is a set Si in Π such that d(u,Si) ≠ d(v,Si).The minimum k for which there is a resolving k-partition of V(G) is called the partition dimension of G,denoted by pd(G).The circulant graph is a graph with vertex set Zn,an additive group ofintegers modulo n,and two vertices labeled i and j adjacent if and only if i - j (mod n) ∈ C,where C C Zn has the property that C =-C and 0(∈) C.The circulant graph is denoted by Xn,△ where A =|C|.In this paper,we study the metric dimension of a family of circulant graphs Xn,3 with connection set C ={1,-n/2,n - 1} and prove that dim(Xn,3) is independent of choice of n by showing that 3 for all n =0 (mod 4),dim(X,n,3) ={ 4 for all n =2 (mod 4).We also study the partition dimension of a family of circulant graphs Xn,4 with connection set C ={±1,±2} and prove that pd(Xn,4) is independent of choice of n and show that pd(X5,4) =5 and 3 forall odd n≥9,pd(Xn,4) ={ 4 for all even n ≥ 6 and n =7.

  7. Experimental study of the drying in dense fluidized beds of a synthetic mud coated with support particulates; Etude experimentale du sechage en lit fluidise dense d'une boue synthetique enrobee sur des particules supports

    Energy Technology Data Exchange (ETDEWEB)

    Gode, C.; Shakourzadeh, K. [Universite de Technologie de Compiegne, L.G.P.I., 60 (France)

    2001-07-01

    This article presents the results of an experimental study of a new drying process for muddy materials and based on the fluidization technique. The granular phase has been obtained by the coating with mud of a porous mineral support, inert and recyclable in the process. Activated porous particulates of alumina (2-5 mm) have been chosen because of their heat transfer properties. A first part of the experimental study concerns the drying process. The second part concerns the attrition and elutriation mechanisms. The experimental measurements have been performed with a laboratory fluidized column (internal diameter = 150 mm) and with a fluidized column (internal diameter = 400 mm) from a semi-industrial facility. The air velocity and the drying temperature are the main adjustment parameters. The working temperatures have been fixed between 20 and 150 deg. C. (J.S.)

  8. Research Progress on the Carrier Chosen in Biological Fluidised bed of Wastwater Treatment%废水处理生物流化床中载体选择的研究进展

    Institute of Scientific and Technical Information of China (English)

    曹玉成; 王平; 常银子

    2004-01-01

    文章系统介绍了废水处理生物流化床中载体的作用及应用现状,重点阐述了三相好氧生物流化床中载体的理化性能及其投放量对处理效果的影响,为载体的选择和开发提供了理论参考依据.

  9. Prediction of dryout heat flux of volumetrically heated particulate beds packed with multi-size particles

    International Nuclear Information System (INIS)

    This paper presents MEWA code calculations for the experiments performed on the POMECO-HT facility to investigate the dryout heat flux of various particulate beds, with the objective to interpret the experimental data and validate the code. The code is then applied to coolability assessment for ex-vessel debris beds related to severe accident scenarios of a boiling water reactor (BWR). The characteristics of a prototypical debris bed, such as multidimensionality and multiple particle sizes are emphasized in this study. The volumetrically heated particulate beds of the POMECO-HT experiments are packed with multi-size particles and equipped with a downcomer to investigate the bottom-fed coolability by natural circulation which demands 2D simulation. The results show that the MEWA code is capable of predicting the coolability of the bed with a downcomer (2D) as well as the top-flooding bed whose dryout heat flux can also be predicted by the Reed model (1D). Given the effective particle diameter (1 mm) and porosity (0.45) defined from a few FCI tests, the ex-vessel debris beds for a BWR chosen here are coolable with varied margins: i) compared with a top-flooding bed (spreading over the entire floor of the cavity), the cylindrical configuration with an annular-gap water supply enhances the coolability comparison , but the gain is marginal since the large diameter of the bed prevents the side coolant from flowing into the center of the bed; ii) a heap-like debris bed reduces rather than improves coolability due to its considerable height and base diameter; iii) a stratified debris bed with a fine-particle layer on the top may challenge the coolability. (author)

  10. Does liver-intestine significantly degrade circulating endogenous substance P in man?

    DEFF Research Database (Denmark)

    Henriksen, J H; Schaffalitzky de Muckadell, Ove B.; Bülow, J B

    1986-01-01

    Elevated concentrations of circulating substance P in patients with liver insufficiency have been ascribed to decreased hepatic degradation. To establish a possible biodegradation of the peptide in liver-intestine and kidneys, the concentration of endogenous immunoreactive substance P...... was determined in various vascular beds during a right-sided catheterization in 13 subjects without liver insufficiency. All subjects had normal values of circulating substance P, and no significant difference was found between systemic plasma and hepatic venous or renal venous concentrations of substance P....... The results indicate that degradation of circulating endogenous substance P in man is not confined to liver-intestine or kidney but may take place in many tissues....

  11. North Atlantic Circulation

    Science.gov (United States)

    Molinari, R.; Bryan, K.; Schott, F.

    The intensity of the North Atlantic winddriven and thermohaline circulation and the close proximity of many oceanographic installations make the North Atlantic a particularly favored region of the world ocean from the standpoint of research in ocean circulation. Recent increases in available data and advances in numerical modeling techniques served as the impetus to convene a joint workshop of modelers and observers working on the North Atlantic with the Scientific Committee on Oceanic Research (SCOR) Working Group (WG) 68 (“North Atlantic Circulation”). Goals of the workshop were to provide an update on data sets and models and to discuss the poleward heat flux problem and possible monitoring strategies. The joint Workshop/SCOR WG-68 meeting was convened by F. Schott (chairman of the working group; Rosenstiel School of Marine and Atmospheric Science, Miami, Fla.), K. Bryan (National Oceanic and Atmospheric Administration/ Geophysical Fluid Dynamics Laboratory (NOAA/GFDL)), and R. Molinari (NOAA/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML)).

  12. Circulation of Stars

    Science.gov (United States)

    Boitani, P.

    2016-01-01

    Since the dawn of man, contemplation of the stars has been a primary impulse in human beings, who proliferated their knowledge of the stars all over the world. Aristotle sees this as the product of primeval and perennial “wonder” which gives rise to what we call science, philosophy, and poetry. Astronomy, astrology, and star art (painting, architecture, literature, and music) go hand in hand through millennia in all cultures of the planet (and all use catasterisms to explain certain phenomena). Some of these developments are independent of each other, i.e., they take place in one culture independently of others. Some, on the other hand, are the product of the “circulation of stars.” There are two ways of looking at this. One seeks out forms, the other concentrates on the passing of specific lore from one area to another through time. The former relies on archetypes (for instance, with catasterism), the latter constitutes a historical process. In this paper I present some of the surprising ways in which the circulation of stars has occurred—from East to West, from East to the Far East, and from West to East, at times simultaneously.

  13. Pulling a patient up in bed

    Science.gov (United States)

    Moving a patient in bed ... You must move or pull someone up in bed the right way to avoid injuring the patient's ... people to safely move a patient up in bed. Friction from rubbing can scrape or tear the ...

  14. 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)

  15. 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.)

  16. CFD simulations of a spouted bed equipment for particle coating

    Energy Technology Data Exchange (ETDEWEB)

    Wolff Filho, Germano Klaus; Cabral, Paulo Alexandre de Moraes [Centro Tecnologico do Exercito (CTEx-RJ), Rio de Janeiro, RJ (Brazil)]. E-mails: klauswolff@ctex.eb.br; paulo@ctex.eb.br

    2007-07-01

    Due to their solids circulation characteristics and excellent gas-particle contact, spouted beds have been used in several engineering applications, including nuclear fuel particles coatings. A laboratory scale equipment was mounted, aiming particles coating for use in nuclear fuel research. The line operates with a spouted bed reactor filled with particles on whose surface the deposition process happens. Some computational simulations, using the CFD commercial code PHOENICS{sup R} , were made in order to show some of the equipment possibilities and limitations. It's important to exhaust theoretical investigations about this kind of system, because experimental conditions seem to be dangerous, beyond associated difficulties in process control and operation. In this work, CFD simulations are used to obtain patterns of solids and gas flows. (author)

  17. Ocean General Circulation Models

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jin-Ho; Ma, Po-Lun

    2012-09-30

    1. Definition of Subject The purpose of this text is to provide an introduction to aspects of oceanic general circulation models (OGCMs), an important component of Climate System or Earth System Model (ESM). The role of the ocean in ESMs is described in Chapter XX (EDITOR: PLEASE FIND THE COUPLED CLIMATE or EARTH SYSTEM MODELING CHAPTERS). The emerging need for understanding the Earth’s climate system and especially projecting its future evolution has encouraged scientists to explore the dynamical, physical, and biogeochemical processes in the ocean. Understanding the role of these processes in the climate system is an interesting and challenging scientific subject. For example, a research question how much extra heat or CO2 generated by anthropogenic activities can be stored in the deep ocean is not only scientifically interesting but also important in projecting future climate of the earth. Thus, OGCMs have been developed and applied to investigate the various oceanic processes and their role in the climate system.

  18. Percutaneous interventions in Fontan circulation

    Directory of Open Access Journals (Sweden)

    Eduardo Franco

    2015-09-01

    Conclusions: Interventional catheterization procedures are often necessary to reach and maintain the fragile Fontan circulation, mainly in patients with right morphology systemic ventricles and fenestrated Fontan conduits.

  19. Torsion testing of bed joints

    DEFF Research Database (Denmark)

    Hansen, Klavs Feilberg; Pedersen, Carsten Mørk

    2008-01-01

    This paper describes a simple test method for determining the torsion strength of a single bed joint between two bricks and presents results from testing using this test method. The setup for the torsion test is well defined, require minimal preparation of the test specimen and the test can...... be carried out directly in a normal testing machine. The torsion strength is believed to be the most important parameter in out-of-plane resistance of masonry walls subjected to bending about an axis perpendicular to the bed joints. The paper also contains a few test results from bending of small walls about...... an axis perpendicular to the bed joints, which indicate the close connection between these results and results from torsion tests. These characteristics make the torsion strength well suited to act as substitute parameter for the bending strength of masonry about an axis perpendicular to the bed joints....

  20. Sea bed mapping and inspection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The conference has 24 presentations on the topics: Sea bed mapping, inspection, positioning, hydrography, marine archaeology, remote operation vehicles and computerized simulation technologies, oil field activities and plans, technological experiences and problems. (tk)

  1. Bed Bugs: The Australian Response

    Directory of Open Access Journals (Sweden)

    Richard C. Russell

    2011-04-01

    Full Text Available Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard ‘A Code of Practice for the Control of Bed Bug Infestations in Australia’ that defines and promotes ‘best practice’ in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in ‘best practice’ while bed bugs remain problematic in Australia.

  2. Better backs by better beds?

    DEFF Research Database (Denmark)

    Bergholdt, Kim; Fabricius, Rasmus N; Bendix, Tom

    2008-01-01

    using the probably most relevant "worst case" data. There were no relevant difference between the effects of the water bed and the foam bed. CONCLUSION: The Waterbed and foam mattress' did influence back symptoms, function and sleep more positively as apposed to the hard mattress, but the differences...... mattresses have a positive effect on LBP, and especially a hard mattress is commonly believed to have a positive effect. METHODS: One hundred sixty CLBP patients were randomized to 1 of 3 groups, having a mattress/bed mounted in their sleeping room for 1 month. The beds were: (1) waterbed (Akva), (2) body......-conforming foam mattress (Tempur), and (3) a hard mattress (Innovation Futon). At baseline and after 4 weeks, a blinded observer interviewed the patients on LBP levels (0-10), daily function (activities of daily living, 0-30), and on the amount of sleeping hours/night. RESULTS: Because of dropout of 19 patients...

  3. Cryogenic helium gas circulation system for advanced characterization of superconducting cables and other devices

    Science.gov (United States)

    Pamidi, Sastry; Kim, Chul Han; Kim, Jae-Ho; Crook, Danny; Dale, Steinar

    2012-04-01

    A versatile cryogenic test bed, based on circulating cryogenic helium gas, has been designed, fabricated, and installed at the Florida State University Center for Advanced Power Systems (FSU-CAPS). The test bed is being used to understand the benefits of integrating the cryogenic systems of multiple superconducting power devices. The helium circulation system operates with four sets of cryocooler and heat exchanger combinations. The maximum operating pressure of the system is 2.1 MPa. The efficacy of helium circulation systems in cooling superconducting power devices is evaluated using a 30-m-long simulated superconducting cable in a flexible cryostat. Experiments were conducted at various mass flow rates and a variety of heat load profiles. A 1-D thermal model was developed to understand the effect of the gas flow parameters on the thermal gradients along the cable. Experimental results are in close agreement with the results from the thermal model.

  4. Bed-exit alarm effectiveness

    Science.gov (United States)

    Capezuti, Elizabeth; Brush, Barbara L.; Lane, Stephen; Rabinowitz, Hannah U.; Secic, Michelle

    2009-01-01

    This study describes the accuracy of two types of bed-exit alarms to detect bed-exiting body movements: pressure-sensitive and a pressure sensitive combined with infrared beam detectors (dual sensor system). We also evaluated the occurrence of nuisance alarms, or alarms that are activated when a participant does not attempt to get out of bed. Fourteen nursing home residents were directly observed for a total of 256 nights or 1,636.5 hours; an average of 18.3 ± 22.3 (± S.D.) nights/participant for an average of 6.4 ± 1.2 hours/night. After adjusting for body movements via repeated measures, Poisson regression modeling, the least squares adjusted means show a marginally significant difference between the type of alarm groups on the number of true positives (mean/S.E.M. = 0.086/1.617) for pressure-sensitive vs. dual sensor alarm (0.593/1.238; p = 0.0599) indicating that the dual sensor alarm may have a higher number of true positives. While the dual sensor bed-exit alarm was more accurate than the pressure sensitive alarm in identifying bed-exiting body movements and reducing the incidence of false alarms, false alarms were not eliminated altogether. Alarms are not a substitute for staff; adequate staff availability is still necessary when residents need or wish to exit bed. PMID:18508138

  5. Northern European Satellite Test Bed

    Science.gov (United States)

    Schuster-Bruce, Alan; Lawson, James; Quinlan, Michael; McGregor, Andrew

    Satellite Based Augmentation Systems are being developed in Europe (EGNOS), the USA (WAAS), and in Japan (MSAS). As part of their support to EGNOS, NATS and Racal have developed and deployed a prototype SBAS system called the Northern European Satellite Test Bed (NEST Bed). NEST Bed uses GPS L1/L2 reference stations at: Aberdeen, Rotterdam, Ankara, Cadiz, Keflavik, and Bronnoysund. Data is sent to the Master Control Centre at NATS Gatwick Services Management Centre for processing. The resulting 250 bits-per-second message is sent to Goonhilly for up-linking by BT to the Navigation Payload of either the Inmarsat AOR-E or F5 spare satellite. NEST Bed was deployed and commissioned during summer 1998, and flight tests were successfully demonstrated at the September 1998 Farnborough Air Show where approaches were flown to Boscombe Down on the DERA BAC1-11 aircraft. In October 1998, a NATS/FAA flight trial was held in Iceland involving NEST Bed and the FAA NSTB. NEST Bed is also being used for SARPS validation.

  6. Contribution of hydrodynamic characteristics on the performance of an aerobic biofilm conical fluidized bed.

    Science.gov (United States)

    Zhou, D; Bi, X T; Dong, S

    2011-01-01

    The performance of a conical fluidized bed (TFB) bioreactor, including the biofilm thickness, microbial space density, microbial cell matrix and its efficiency for COD degradation at a bed expansion ratio of 14 to 90%, was studied and compared with a cylindrical fluidized bed (CFB) bioreactor. The hydrodynamic characteristics of the TFB, especially the internal-circulation of bioparticles associated with its unique tapered geometry of the bed, created a much more uniform axial distribution of the bioparticles, leading to the formation of thinner and more compacted biofilms in the TFB compared to that in the CFB. The thinner biofilm in the TFB tended to be stable and possessed more than 6 times of microbial population density compared to the CFB. As a result, thinner biofilms in the TFB contributed to a higher COD removal efficiency, which remained at over 95% at operated expansion ratios, about 15 to 25% higher than that in the CFB. PMID:21436551

  7. A study of the fluid dynamics of the spouted bed using CFD

    Directory of Open Access Journals (Sweden)

    C. R. Duarte

    2005-06-01

    Full Text Available The spouted bed has been used in drying, granulation, catalytic polymerization, residue treatment and coating of several materials. Its success is attributed to its solids circulation characteristics and excellent gas-particle contact. In this work the pattern of solids and gas flows in a spouted bed was numerically simulated using a Eulerian multiphase model. The computational work was significantly reduced for axisymmetric gas-solids flows. The simulated velocity and voidage profiles were compared with results obtained in our laboratory (with a two-dimensional spouted bed using soybean seed and by He et al. (1994 (with a cylindrical spouted bed and glass sphere. The simulated results showed good agreement with the experimental data for both geometries studied.

  8. Sino-Danish Brain Circulation

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Du, Xiangyun; Søndergaard, Morten Karnøe

    2014-01-01

    China is faced with urgent needs to develop an economically and environmentally sustainable economy based on innovation and knowledge. Brain circulation and research and business investments from the outside are central for this development. Sino-American brain circulation and research...... and investment by overseas researchers and entrepreneurs are well described. In that case, the US is the center of global R&D and S&T. However, the brain circulation and research and investments between a small open Scandinavian economy, such as Denmark, and the huge developing economy of China are not well...... understood. In this case, Denmark is very highly developed, but a satellite in the global R&D and S&T system. With time and the growth of China as a R&D and S&T power house, both Denmark and China will benefit from brain circulation between them. Such brain circulation is likely to play a key role in flows...

  9. TROPICAL METEOROLOGY & Climate: Hadley Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jian; Vecchi, Gabriel A.

    2015-01-30

    The Hadley circulation, a prominent circulation feature characterized by rising air near the Equator and sinking air in the subtropics, defines the position of dry subtropical areas and is a fundamental regulator of the earth’s energy and momentum budgets. The character of the Hadley circulation, and its related precipitation regimes, exhibits variation and change in response to both climate variability and radiative forcing changes. The strength and position of the Hadley circulation change from year to year paced by El Niño and La Niña events. Over the last few decades of the twentieth century, the Hadley cell has expanded poleward in both hemispheres, with changes in atmospheric composition (including stratospheric ozone depletion and greenhouse gas increases) thought to have contributed to its expansion. This article introduces the basic phenomenology and driving mechanism of the Hadley circulation and discusses its variations under both natural and anthropogenic climate forcings.

  10. 49 CFR 236.336 - Locking bed.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking bed. 236.336 Section 236.336 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Instructions § 236.336 Locking bed. The various parts of the locking bed, locking bed supports, and tappet...

  11. Plasma assisted measurements of alkali metal concentrations in pressurised combustion processes

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Haeyrinen, V. [Tampere Univ. of Technology (Finland)

    1997-10-01

    In this project the continuous alkali measurement method plasma excited alkali resonance line spectroscopy (PEARLS) was developed, tested and demonstrated in pressurised combustion facilities. The PEARLS method has been developed at Tampere University of Technology (TUT). During 1994-1996 the PEARLS method was developed from the laboratory level to an industrial prototype. The alkali measuring instrument has been tested and used for regular measurements in four different pressurised combustion installations ranging up to industrial pilot scale. The installations are: (1) a pressurised entrained flow reactor (PEFR) at VTT Energy in Jyvaeskylae, Finland (2) a pressurised fluidised bed combustion facility, called FRED, at DMT in Essen, Germany. (3) a 10 MW pressurised circulating fluidised bed combustion pilot plant at Foster Wheeler Energia Oy in Karhula, Finland (4) PFBC Research Facility at ABB Carbon in Finspaang, Sweden

  12. 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.

  13. Designing a CR Test bed

    DEFF Research Database (Denmark)

    Cattoni, Andrea Fabio; Buthler, Jakob Lindbjerg; Tonelli, Oscar;

    2014-01-01

    Research on intelligent and reconfigurable wireless systems is in continuous evolution. Nevertheless, in order to fix some keystones, more and more researchers are entering the idea of research-oriented test beds. Unfortunately, it is very difficult for a wide number of research groups to start...... with their own set up, since the potential costs and efforts could not pay back in term of expected research results. Software Defined Radio solutions offer an easy way to communication researchers for the development of customized research test beds. While several hardware products are commercially available...... they are up and running in generating results. With this chapter we would like to provide a tutorial guide, based on direct experience, on how to enter in the world of test bed-based research, providing both insight on the issues encountered in every day development, and practical solutions. Finally...

  14. 循环流化床垃圾焚烧炉混烧羊毛脂废料试验研究%Experimental Study on Co-firing of Lanolin Waste and Municipal Solid Waste in a Circulating Fluidized Bed Incinerator

    Institute of Scientific and Technical Information of China (English)

    马攀; 马增益; 陈继华; 刘渊源; 池涌; 严建华; 岑可法; 金忠财

    2012-01-01

    The objective of this work was to investigate the feasibility of utilizing lanolin waste as auxiliary fuel in a 400 t/d circulating fluidized bed(CFB) municipal solid waste incinerator(MSWI).The combustion stability,combustion efficiency and pollutant emissions were investigated during the co-firing of the MSW,coal and lanolin waste.The results show that the addition of lanolin waste leads to lower CO,N2O,SO2,particulate matter emissions and unburned carbon content in fly ash.The CFB combustion efficiency increases as the amount of lanolin waste adding from 0.7t/h to 1.8t/h.On the other hand,NO concentration increases with the amount of lanolin waste added and the variation of HCl content did not change remarkably.Raising furnace temperature causes increasing of NO emission and decreasing of CO emission.All gas emissions can meet the demands of the Chinese EPA standard.The study demonstrates the technical feasibility of lanolin waste as auxiliary fuel and CFB has a good adaptability.%以生活垃圾和煤混烧的400 t/d循环流化床垃圾焚烧锅炉为依托,对某大型生物医药公司的羊毛脂废料进行混烧的工业试验,了解混烧该废料对垃圾焚烧炉燃烧稳定性、炉膛温度、锅炉尾部常规污染物排放及飞灰含碳量的影响,以研究羊毛脂废料代替燃煤作为垃圾发电辅助燃料的可行性。试验表明,随着羊毛脂废料掺混量的增加,煤的添加量随之下降,烟气中的烟尘浓度,CO和SO2含量以及飞灰含碳量均有所下降;NO含量随掺混量的增加而增加,N2O随掺混量的增加而减少;HCl含量受掺混量影响不明显。随床温升高NO排放增加,CO排放下降,SO2和HCl浓度基本不变。试验表明循环流化床垃圾焚烧锅炉对羊毛脂废料具有良好的适应性。

  15. The circulation physiology of agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Cao Zhiping; Richard Dawson

    2007-01-01

    This paper represents an effort to enlarge the understanding of the biophysical foundation of agroecosystems by using an analogy with the circulation of the blood in the human body. The circulation function in the human body can be represented as arterial pressure. The factors affecting arterial pressure in the human body have direct counterparts in the cultivation-husbandry system. The relationship between circulation pressure and the factors affecting that pressure in the cultivation-husbandry system are similar to the relationship between the arterial pressure and factors affecting arterial pressure in the human body. Furthermore, circulation resistance in the cultivation-husbandry system can be shown to be analogous to the calculation of peripheral resistance in the human body by Poiseuille's formula.

  16. Combined gas-steam power stations with pressurized fluidized bed combustion (PFBC) of coal

    Energy Technology Data Exchange (ETDEWEB)

    Grzegorczyk, W. (Energoprojekt, Warsaw (Poland))

    1990-11-01

    Presents pressurized fluidized bed combustion (PFBC) of coal that combines fluidized bed combustion with two-agent gas-steam circulation. PFBC permits clean combustion of coal with low calorific value and high ash and sulfur content. The ABB company offered a block for the Pruszkow power plant in Poland. Specifications of the block are given as: thermal power in fuel 430 MW and electrical power 175 MW. The boiler, gas turbine and turbine set are described. Technical and economic indices are given. The supplier attests that the emission values of 70 mg sulfur dioxide per MJ and 120 mg of nitrogen dioxide will not be exceeded under normal conditions.

  17. Arsenic removal via ZVI in a hybrid spouted vessel/fixed bed filter system

    OpenAIRE

    Calo, Joseph M.; Madhavan, Lakshmi; Kirchner, Johannes; Bain, Euan J.

    2012-01-01

    The description and operation of a novel, hybrid spouted vessel/fixed bed filter system for the removal of arsenic from water are presented. The system utilizes zero-valent iron (ZVI) particles circulating in a spouted vessel that continuously generates active colloidal iron corrosion products via the “self-polishing” action between ZVI source particles rolling in the moving bed that forms on the conical bottom of the spouted vessel. This action also serves as a “surface renewal” mechanism fo...

  18. EXTERNAL-LOOP AIRLIFT MAGNETICALLY STABILIZED BED--MINIMUM STABILIZATION AND FLUIDIZATION CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    Jordan Hristov

    2005-01-01

    Experimental study of an airlift with a magnetically stabilized bed in the riser bottom has been performed.External magnetic field allows easy control of magnetized bed structure and liquid circulation rate. Minimum stabilization and fluidization conditions have been determined experimentally and by a three-line graphical method. Semi-empirical data correlations of sections of the experimental curves have been performed. Scaling relationships known from non-magnetic airlift are applicable too, but with the assumption that the magnetic field affects the loop friction coefficient only.

  19. Atmospheric Circulation of Terrestrial Exoplanets

    OpenAIRE

    Showman, Adam P.; Wordsworth, Robin D.; Merlis, Timothy M.; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical a...

  20. Improved Fluidized Bed Drying Technology for Wood Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Berghel, Jonas

    2004-04-01

    In this thesis, I discuss experiences from designing, building and evaluating two research plants, which use circulating, atmospheric pressure superheated steam as drying medium for drying sawdust in a fluidized bed. The increased use of pellets has created a demand for new drying equipment at the Swedish pellet plants. The underlying cause is that almost all of the available dried material, such as wood shavings, is already in use. The remaining biofuel materials, primarily wet sawdust need drying before entering the pellet process. The primary demands on the drying process were an uncomplicated design and efficient energy use. A key aim was to improve the drying technique used in the Swedish wood fuel system with specially interest on the control system. Sawdust has been tested in both a full scale and a laboratory scale dryers. The tests were done in a spouted bed. The product of the steam mass flow and the enthalpy difference limits the drying capacity. The tests showed that it is possible to use the temperature after the dryer as a control parameter for the outgoing moisture content in a spouted bed dryer. The results and conclusions can be very useful when designing a similar full scale drying system.

  1. 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

  2. Advanced sorbent development progam; development of sorbents for moving-bed and fluidized-bed applications

    International Nuclear Information System (INIS)

    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 (900-1000F) 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 assessment and

  3. Experimental investigation of a draft tube spouted bed for effects of geometric parameters on operation

    Science.gov (United States)

    Azizaddini, Seyednezamaddin; Lin, Weigang; Dam-Johansen, Kim

    2016-06-01

    Experiments are performed in a draft tube spouted bed (DTSB) to investigate effects of the operating conditions and the geometric parameters on the hydrodynamics. Geometry parameters, such as heights of the entrained zone, draft tube inner diameter, inner angle of the conical section were studied. Increasing the draft tube inner diameter, sharper inner angle of the conical section and higher height of entrained zone increase the internal solid circulation rate and the pressure drop. Even though, for all different configurations, higher gas feeding rate leads to higher internal solid circulation rate considering a maximum value.

  4. Experimental investigation of a draft tube spouted bed for effects of geometric parameters on operation

    DEFF Research Database (Denmark)

    Azizaddini, Seyednezamaddin; Lin, Weigang; Dam-Johansen, Kim

    2016-01-01

    Experiments are performed in a draft tube spouted bed (DTSB) to investigate effects of the operating conditions and the geometric parameters on the hydrodynamics. Geometry parameters, such as heights of the entrained zone, draft tube inner diameter, inner angle of the conical section were studied....... Increasing the draft tube inner diameter, sharper inner angle of the conical section and higher height of entrained zone increase the internal solid circulation rate and the pressure drop. Even though, for all different configurations, higher gas feeding rate leads to higher internal solid circulation rate...

  5. [Historical analysis of the hospital bed].

    Science.gov (United States)

    Fajardo-Ortiz, Guillermo; Fajardo-Dolci, Germán

    2010-01-01

    Until now the bed has been the basic physical resource in hospitals. This type of furniture has served to study and treat patients, through out the centuries it has undergone changes in the materials they are made of dimensions, functionality, accessories, aesthetic, and design. The hospital bed history is not well known, there are thousands of documents about the evolution of hospitals, but not enough is known about hospital beds, a link between the past and the present. The medical, anthropological, technological, social, and economic dynamics and knowledge have produced a variety of beds in general and hospital beds in particular. From instinctive, rustic, poor and irregular "sites" that have differed in shape and size they had evolved into ergonomic equipment. The history of the hospital bed reflects the culture, techniques and human thinking. Current hospital beds include several types: for adults, for children, for labor, for intensive therapy, emergency purposes, census and non census beds etc.

  6. Chinese Bedding Technology Standard under Drafting

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    National Home Textile Standardization Technology Committee(NHTSTC)set up its Bedding Branch Committee. This will promote the work of Chinese bedding technology standardization and a symbol that China step up to meet the

  7. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow. Key Points Sinking occurs in a narrow boundary layer along the eastern boundary Surface western boundary current switches into an eastern boundary current Water exchange in the Strait of Bab el Mandeb is not hydraulically controlled © 2014. American Geophysical Union. All Rights Reserved.

  8. Fluidized Bed Reactor as Solid State Fermenter

    OpenAIRE

    Krishnaiah, K.; Janaun, J.; Prabhakar, A.

    2005-01-01

    Various reactors such as tray, packed bed, rotating drum can be used for solid-state fermentation. In this paper the possibility of fluidized bed reactor as solid-state fermenter is considered. The design parameters, which affect the performances are identified and discussed. This information, in general can be used in the design and the development of an efficient fluidized bed solid-state fermenter. However, the objective here is to develop fluidized bed solid-state fermenter for palm kerne...

  9. The Invertibility, Explicit Determinants, and Inverses of Circulant and Left Circulant and g-Circulant Matrices Involving Any Continuous Fibonacci and Lucas Numbers

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices play an important role in solving delay differential equations. In this paper, circulant type matrices including the circulant and left circulant and g-circulant matrices with any continuous Fibonacci and Lucas numbers are considered. Firstly, the invertibility of the circulant matrix is discussed and the explicit determinant and the inverse matrices by constructing the transformation matrices are presented. Furthermore, the invertibility of the left circulant and g-circulant matrices is also studied. We obtain the explicit determinants and the inverse matrices of the left circulant and g-circulant matrices by utilizing the relationship between left circulant, g-circulant matrices and circulant matrix, respectively.

  10. Does liver-intestine significantly degrade circulating endogenous substance P in man?

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Schaffalitzky de Muckadell, O B; Bülow, J B

    1986-01-01

    was determined in various vascular beds during a right-sided catheterization in 13 subjects without liver insufficiency. All subjects had normal values of circulating substance P, and no significant difference was found between systemic plasma and hepatic venous or renal venous concentrations of substance P......Elevated concentrations of circulating substance P in patients with liver insufficiency have been ascribed to decreased hepatic degradation. To establish a possible biodegradation of the peptide in liver-intestine and kidneys, the concentration of endogenous immunoreactive substance P...

  11. Bed Bug Education for School Maintenance

    Science.gov (United States)

    Henriksen, Missy

    2012-01-01

    Bed bugs are a growing problem, not only in homes and hotels, but also in schools and colleges. Facility administrators and staff need to understand the bed bug resurgence and develop best practices to deal with an infestation. In this article, the author offers tips for preventing and treating bed bugs in school and university settings.

  12. 21 CFR 868.5180 - Rocking bed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rocking bed. 868.5180 Section 868.5180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5180 Rocking bed. (a) Identification. A rocking bed is a...

  13. Heat Transfer in Segregated Fluidized Beds Part 2: Particle Motion and Its Effects on the Heat transfer in the Segregated Fluidized Beds

    Science.gov (United States)

    Gu, Yihua; Satoh, Isao; Saito, Takushi; Kawaguchi, Tatsuya

    In our previous paper, particle and temperature segregations in a fluidized bed of binary particle mixtures were experimentally examined, and heat transfer in the segregated fluidized bed was investigated. As the results, it was shown that the temperature segregation results mainly from low heat transfer coefficient through the interface layer, which exists between the flotsam-rich and jetsam-rich layers, and that the heat transfer coefficient increases rapidly with increasing the excess gas velocity. Following our previous paper, particle motion in the segregated fluidized bed was experimentally investigated in this paper, in order to make quantitative discussion on the relation between the heat transfer coefficient and particle motion in the interface layer. In the experiment, the Particle Imaging Velocimetry (PIV) method was applied to study the concentration and motion of particles in the segregated fluidized bed. A modified solid circulation model was built up to model the particle motion in the segregated fluidized bed. The experiment results showed that the vertical particle exchange rate of the interface layer increases with the excess gas velocity, and that the vertical heat transfer coefficient through the interface layer is mainly determined by the average particle exchange rate in the interface layer. Variations of the apparent thermal conductivity at different height in the particle layers were also determined by the vertical variation of the particle exchange rate. It was shown that the heat transfer coefficient or the thermal conductivity in the interface layer is influenced by the densities and specific heat capacities of the particles.

  14. [Circulating nucleic acids and infertility].

    Science.gov (United States)

    Scalici, E; Mullet, T; Ferrières Hoa, A; Gala, A; Loup, V; Anahory, T; Belloc, S; Hamamah, S

    2015-09-01

    Circulating nucleic acids (cell-free DNA and microRNAs) have for particularity to be easily detectable in the biological fluids of the body. Therefore, they constitute biomarkers of interest in female and male infertility care. Indeed, in female, they can be used to detect ovarian reserve disorders (polycystic ovary syndrome and low functional ovarian reserve) as well as to assess follicular microenvironment quality. Moreover, in men, their expression levels can vary in case of spermatogenesis abnormalities. Finally, circulating nucleic acids have also the ability to predict successfully the quality of in vitro embryo development. Their multiple contributions during assisted reproductive technology (ART) make of them biomarkers of interest, for the development of new diagnostic and/or prognostic tests, applied to our specialty. Circulating nucleic acids would so offer the possibility of personalized medical care for infertile couples in ART. PMID:26298813

  15. Atmospheric Circulation of Terrestrial Exoplanets

    CERN Document Server

    Showman, Adam P; Merlis, Timothy M; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadle...

  16. Review of acute cancer beds.

    LENUS (Irish Health Repository)

    Evans, D S

    2012-01-01

    A review of admissions to cancer services at University Hospital Galway (UHG) was undertaken to assess the appropriateness of hospital usage. All cancer specialty patients admitted from 26-28 May 2009 were reviewed (n = 82). Chi square tests, Exact tests, and One-way ANOVA were utilised to analyse key issues emerging from the data. Fifty (61%) were classified as emergencies. Twenty three (67%) occupied a designated cancer bed with 24 (30%) in outlying non-oncology wards. The mean length of stay was 29.3 days. Possible alternatives to admission were identified for 15 (19%) patients. There was no evidence of discharge planning for 50 (60%) admissions. There is considerable potential to make more appropriate utilisation of UHG for cancer patients, particularly in terms of reducing bed days and length of stay and the proportion of emergency cancer admissions, and further developing integrated systems of discharge planning.

  17. 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

  18. Bed bathing patients in hospital

    OpenAIRE

    L Downey; Lloyd, Hilary

    2008-01-01

    There are a number of circumstances that may affect an individual's ability to maintain personal hygiene. Hospitalised patients, and in particular those who are bedridden, may become dependent on nursing staff to carry out their hygiene needs. Assisting patients to maintain personal hygiene is a fundamental aspect of nursing care. However, it is a task often delegated to junior or newly qualified staff. This article focuses on the principles of bed bathing patients in hospital, correct proced...

  19. THE BAUXITES AND JELAR - BEDS

    Directory of Open Access Journals (Sweden)

    Krešimir Sakač

    1993-12-01

    Full Text Available Minor bauxite deposits and occurrences were formed in technically disturbed environments in the middle part of the Adriatic geotectonic unit in Dinarides, contemporary with the clastic Jelar-beds in the Late Lutetian time. Uneven chemical composition of these Eocene bauxites, their sporadic occurrences in developed paleorelief as well as characteristic petrographic composition of the immediate overlying rocks point out at different genetical conditions (the paper is published in Croatian.

  20. Proper Sizing of Circulation Pumps

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Nørgaard, Jørgen

    2007-01-01

    , but the results can be applied to Europe in general. Despite the small sample of houses involved in the test, 15 houses, some rather safe conclusions can be drawn from the results, which showed that newly developed pumps with power consumption around 5-8 W, can perform the task of circulating the water...... as well as their pollution during operation. Policy measures are proposed of how to ensure that in the future only such energy saving pumps are installed. Furthermore, on the basis of the historic experiences with circulation pumps some con¬clusions are drawn on how to investigate, develop and market new...

  1. Techno-Economic Study of Adsorption Processes for Pre-Combustion Carbon Capture at a Biomass CHP Plant

    OpenAIRE

    Oreggioni, Gabriel David; Friedrich, Daniel; Brandani, Stefano; Ahn, Hyungwoong

    2014-01-01

    An exemplary 10 MWth biomass CHP plant with a FICFB (Fast Internally Circulating Fluidised Bed) gasifier and Jenbacher type 6 gas engine was simulated to estimate the power and thermal outputs. The biomass-fuelled CHP plant was modified for carbon capture using either adsorption or amine process. It was found that a two-stage, two-bed PVSA (Pressure Vacuum Swing Adsorption) unit applied to syngas stream for pre-combustion capture spent less specific energy per captured CO2 than a conventional...

  2. The statistical character of packed-bed heat transport properties

    OpenAIRE

    Wijngaarden, R.J.; Westerterp, K. R.

    1992-01-01

    Packed beds are essentially heterogeneous on a pellet scale. For random packed beds this heterogeneity causes a statistical character both on a pellet and bed scale. We discuss experimental results which deal with bed-scale statistics.

  3. Method and apparatus for a combination moving bed thermal treatment reactor and moving bed filter

    Energy Technology Data Exchange (ETDEWEB)

    Badger, Phillip C.; Dunn, Jr., Kenneth J.

    2015-09-01

    A moving bed gasification/thermal treatment reactor includes a geometry in which moving bed reactor particles serve as both a moving bed filter and a heat carrier to provide thermal energy for thermal treatment reactions, such that the moving bed filter and the heat carrier are one and the same to remove solid particulates or droplets generated by thermal treatment processes or injected into the moving bed filter from other sources.

  4. NUMERICAL PREDICTION OF PARTICLE MIXING BEHAVIOR IN A BUBBLING FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    WU Chun-liang; ZHAN Jie-min

    2007-01-01

    In this article the hard-sphere Discrete Particle Model (DPM) is used to study the mixing behavior of particles in the 2-D fluidized bed. Different flow patterns in the bed for two kinds of inlet configurations, namely free bubbling and jet bubbling mode, are captured by the numerical model, under specific superficial gas velocities. To examine the degree of particle mixing, the Fan index is applied. The numerical results show that the rate of particle mixing is larger in the jet bubbling than that in the free bubbling mode. The gross circulations of particles in the jet bubbling bed give a higher degree of mixing because of the involvement of a greater number of particles.

  5. 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.

  6. Energetic, ecologic and fluid-dynamic analysis of a fluidized bed gasifier operating with sugar cane bagasse

    International Nuclear Information System (INIS)

    This work aims to study the thermodynamic, ecological and fluid-dynamic aspects of a circulating fluidized bed gasifier using sugar cane bagasse as biomass, in order to estimate a model of its normal operation. In the initial stage was analysed the composition of biomass selected (sugar cane bagasse) and its lower heating value (LHV) was calculated. The energy balance of the gasifier was done, being the volumetric flow of air, synthesis gas and biomass estimated. Also the power produced by this gasifier was theoretically estimated. Then the circulating fluidized bed gasifier was designed for operation with approximately 100 kg/h of processed biomass. Cross-sectional area of the reactor, feeder size, diameter of the exit zone of the gases and minimum height of the expanded bed were selected. Some bed gasifier hydrodynamic factors were also studied. The minimum fluidization velocity, fluidization terminal velocity, and average fluidizing velocity were calculated, in order to understand the fluid-dynamic behaviour of gasification of this fuel. It was obtained a theoretical model that can support a possible prototype of circulating fluidized bed gasifier biomass. Finally, there were studied the ecological aspects of the gasifier, through an overall methodology. Ecological efficiencies were estimated for two scenarios: first considering the carbon cycle and thereafter disregarding the carbon cycle. In both cases, it can be proved the ecological viability of the project. -- Highlights: • we develop a methodology to size a fluidized bed gasifier. • we validate this methodology comparing to a fixed bed gasifier values. • we aggregate ecological efficiency to this methodology

  7. Equilibrium bed-concentration of nonuniform sediment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Knowledge of the equilibrium bed-concentration is vital to mathematical modeling of the river-bed deformation associated with suspended load but previous investigations only dealt with the reference concentration of uniform sediment because of difficulties in observation of the bed-concentration. This work is a first attempt to develop a theoretical formula for the equilibrium bed-concentration of any fraction of nonuniform sediment defined at the bed-surface. The formula is based on a stochastic-mechanistic model for the exchange of nonuniform sediment near the bed, and described as a function of incipient motion probability, non-ceasing probability, pick-up probability, and the ratio of the average single-step continuous motion time to static time. Comparison of bed-concentration calculated from the proposed formula with the measured data showed satisfactory agreement, indicating the present formula can be used for solving the differential equation governing the motion of suspended load.

  8. Bed bug aggregation pheromone finally identified.

    Science.gov (United States)

    Gries, Regine; Britton, Robert; Holmes, Michael; Zhai, Huimin; Draper, Jason; Gries, Gerhard

    2015-01-19

    Bed bugs have become a global epidemic and current detection tools are poorly suited for routine surveillance. Despite intense research on bed bug aggregation behavior and the aggregation pheromone, which could be used as a chemical lure, the complete composition of this pheromone has thus far proven elusive. Here, we report that the bed bug aggregation pheromone comprises five volatile components (dimethyl disulfide, dimethyl trisulfide, (E)-2-hexenal, (E)-2-octenal, 2-hexanone), which attract bed bugs to safe shelters, and one less-volatile component (histamine), which causes their arrestment upon contact. In infested premises, a blend of all six components is highly effective at luring bed bugs into traps. The trapping of juvenile and adult bed bugs, with or without recent blood meals, provides strong evidence that this unique pheromone bait could become an effective and inexpensive tool for bed bug detection and potentially their control. PMID:25529634

  9. Conservation of Circulation in Magnetohydrodynamics

    CERN Document Server

    Bekenstein, J D; Bekenstein, Jacob D.; Oron, Asaf

    2000-01-01

    We demonstrate, both at the Newtonian and (general) relativistic levels, theexistence of a generalization of Kelvin's circulation theorem (for pure fluids)which is applicable to perfect magnetohydrodynamics. The argument is based onthe least action principle for magnetohydrodynamic flow. Examples of the newconservation law are furnished. The new theorem should be helpful inidentifying new kinds of vortex phenomena distinct from magnetic ropes or fluidvortices.

  10. Neural Control of the Circulation

    Science.gov (United States)

    Thomas, Gail D.

    2011-01-01

    The purpose of this brief review is to highlight key concepts about the neural control of the circulation that graduate and medical students should be expected to incorporate into their general knowledge of human physiology. The focus is largely on the sympathetic nerves, which have a dominant role in cardiovascular control due to their effects to…

  11. VanderLaan Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Hongyan Pan

    2015-01-01

    Full Text Available Circulant matrices have become a satisfactory tools in control methods for modern complex systems. In the paper, VanderLaan circulant type matrices are presented, which include VanderLaan circulant, left circulant, and g-circulant matrices. The nonsingularity of these special matrices is discussed by the surprising properties of VanderLaan numbers. The exact determinants of VanderLaan circulant type matrices are given by structuring transformation matrices, determinants of well-known tridiagonal matrices, and tridiagonal-like matrices. The explicit inverse matrices of these special matrices are obtained by structuring transformation matrices, inverses of known tridiagonal matrices, and quasi-tridiagonal matrices. Three kinds of norms and lower bound for the spread of VanderLaan circulant and left circulant matrix are given separately. And we gain the spectral norm of VanderLaan g-circulant matrix.

  12. A study of dilute to dense flow in a circulating fluidized bed

    DEFF Research Database (Denmark)

    Ibsen, Claus Hübbe; Solberg, Tron; Hjertager, Bjørn H.

    2001-01-01

    based on a Multiphase Computational Fluid Dynamics code, where the conservation equations for the solid phases are based on the kinetic theory of granular flow. The experimental data is used to evaluate the multiphase CFD code with alternative gas-solid drag models, which showed an improved agreement......This work concerns a experimental and numerical study on how the amount of particles influences the flow in the CFB. Experiments are performed with a 1D Laser and Phase doppler anemometry, whereby data of axial velocity, RMS velocity and particle diameter is obtained. The numerical simulations are...

  13. Direct Causticizing for Black Liquor Gasification in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Scott Sinquefield; Xiaoyan Zeng, Alan Ball

    2010-03-02

    Gasification of black liquor (BLG) has distinct advantages over direct combustion in Tomlinson recovery boilers. In this project we seek to resolve causticizing issues in order to make pressurized BLG even more efficient and cost-effective. One advantage of BLG is that the inherent partial separation of sulfur and sodium during gasification lends itself to the use of proven high yield variants to conventional kraft pulping which require just such a separation. Processes such as polysulfide, split sulfidity, ASAQ, and MSSAQ can increase pulp yield from 1% to 10% over conventional kraft but require varying degrees of sulfur/sodium separation, which requires additional [and costly] processing in a conventional Tomlinson recovery process. However during gasification, the sulfur is partitioned between the gas and smelt phases, while the sodium all leaves in the smelt; thus creating the opportunity to produce sulfur-rich and sulfur-lean white liquors for specialty pulping processes. A second major incentive of BLG is the production of a combustible product gas, rich in H2 and CO. This product gas (a.k.a. “syngas”) can be used in gas turbines for combined cycle power generation (which is twice as efficient as the steam cycle alone), or it can be used as a precursor to form liquid fuels, such as dimethyl ether or Fischer Tropsh diesel. There is drawback to BLG, which has the potential to become a third major incentive if this work is successful. The causticizing load is greater for gasification of black liquor than for combustion in a Tomlinson boiler. So implementing BLG in an existing mill would require costly increases to the causticizing capacity. In situ causticizing [within the gasifier] would handle the entire causticizing load and therefore eliminate the lime cycle entirely. Previous work by the author and others has shown that titanate direct causticizing (i.e. in situ) works quite well for high-temperature BLG (950°C), but was limited to pressures below about 5 bar. It is desirable however to operate BLG at 20-30 bar for efficiency reasons related to either firing the syngas in a turbine, or catalytically forming liquid fuels. This work focused on achieving high direct causticizing yields at 20 bars pressure. The titanate direct causticizing reactions are inhibited by CO2. Previous work has shown that the partial pressure of CO2 should be kept below about 0.5 bar in order for the process to work. This translates to a total reactor pressure limit of about 5 bar for airblown BLG, and only 2 bar for O2-blown BLG. In this work a process was developed in which the CO2 partial pressure could be manipulated to a level under 0.5 bar with the total system pressure at 10 bar during O2-blown BLG. This fell short of our 20 bar goal but still represents a substantial increase in the pressure limit. A material and energy balance was performed, as well as first-pass economics based on capital and utilities costs. Compared to a reference case of using BLG with a conventional lime cycle [Larson, 2003], the IRR and NVP were estimated for further replacing the lime kiln with direct causticizing. The economics are strongly dependent on the price of lime kiln fuel. At $6/mmBTU the lime cycle is the clear choice. At $8/mmBTU the NPV is $10M with IRR of 17%. At $12/mmBTU the NPV is $45M with IRR of 36%. To further increase the total allowable pressure, the CO2 could be further decreased by further decreasing the temperature. Testing should be done at 750C. Also a small pilot should be built.

  14. Simulation of gas and particle flow in a circulating fluidized bed; Kaasu- ja kiintoainevirtauksen simulointi kiertoleijukattilassa

    Energy Technology Data Exchange (ETDEWEB)

    Kallio, S. [Aabo Akademi, Turku (Finland). Inst. of Heat Engineering

    1996-12-01

    The aim of this work was to study the effects of different parameters on the flow behaviour in a CFB riser by means of empirical models based on measurement data and a computer code based on macroscopic equations for multiphase flow. The effects of primary air velocity and riser geometry have been observed in the results. Simulation of secondary air flow proved to be problematic with the software used. In the project, also analyses of measurement data from cold model experiments has been performed. Moreover, the possibilities to use commercial CFD codes for simulation of gas-solids flow were investigated. The code FLUENT seemed promising. (author)

  15. The Berlin emissivity database (BED)

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Moroz, L.

    2008-03-01

    Remote-sensing infrared spectroscopy is the principal field of investigation for planetary surfaces composition. Past, present and future missions to the solar system bodies include in their payload, instruments measuring the emerging radiation in the infrared range. Apart from measuring the reflected radiance, more and more spacecrafts are equipped with instruments measuring directly the emitted radiation from the planetary surface. The emitted radiation is not only a function of the composition of the material but also of its texture and especially the grain size distribution. For the interpretation of the measured data an emissivity spectral library of planetary analogue materials in grain size fractions appropriate for planetary surfaces is needed. The Berlin emissivity database (BED) presented here is focused on relatively fine-grained size separates, providing thereby a realistic basis for the interpretation of thermal emission spectra of planetary regoliths. The BED is therefore complimentary to existing thermal emission libraries, like the ASU library for example. BED currently contains emissivity spectra of plagioclase and potassium feldspars, low Ca and high Ca pyroxenes, olivine, elemental sulfur, Martian analogue minerals and volcanic soils, and a lunar highland soil sample measured in the wavelength range from 7 to 22 μm as a function of particle size. For each sample we measured the spectra of four particle size separates ranging from <25 to 250 μm. The device we used is built at DLR (Berlin) and is coupled to a Fourier-transform infrared spectrometer Bruker IFS 88 purged with dry air and equipped with a nitrogen-cooled MCT detector. All spectra were acquired with a spectral resolution of 4 cm -1. We are currently working on upgrading our emissivity facility. A new spectrometer (Bruker VERTEX 80 V) and new detectors will allow us to measure the emissivity of samples in the wavelength range from 1 to 50 μm in a vacuum environment. This will be

  16. MICROTURBULENCE IN GRAVEL BED STREAMS

    Science.gov (United States)

    Papanicolaou, T.; Tsakiris, A. G.; Kramer, C. M.

    2009-12-01

    The overarching objective of this investigation was to evaluate the role of relative submergence on the formation and evolution of cluster microforms in gravel bed streams and its implications to bedload transport. Secondary objectives of this research included (1) a detailed analysis of mean flow measurements around a clast; and (2) a selected number of experimental runs where the mean flow characteristics are linked together with the bed micro-topography observations around a clast. It is hypothesized that the relative submergence is an important parameter in defining the feedback processes between the flow and clasts, which governs the flow patterns around the clasts, thus directly affecting the depositional patterns of the incoming sediments. To examine the validity of the hypothesis and meet the objectives of this research, 19 detailed experimental runs were conducted in a tilting, water recirculating laboratory flume under well-controlled conditions. A fixed array of clast-obstacles were placed atop a well-packed bed with uniform size glass beads. During the runs, multifractional spherical particles were fed upstream of the clast section at a predetermined rate. State-of-the-art techniques/instruments, such as imaging analysis software, Large Scale Particle Velocimeter (LSPIV) and an Acoustic Doppler Velocimetry (ADV) were employed to provide unique quantitative measurements for bedload fluxes, clast/clusters geomorphic patterns, and mean flow characteristics in the vicinity of the clusters. Different flow patterns were recorded for the high relative submergence (HRS) and low relative submergence (LRS) experimental runs. The ADV measurements provided improved insight about the governing flow mechanisms for the HRS runs. These mechanisms were described with flow upwelling at the center of the flume and downwelling occurring along the flume walls. Flow downwelling corresponded to an increase in the free surface velocity. Additionally, the visual observations

  17. [Special beds. Pulmonary therapy system].

    Science.gov (United States)

    Calixto Rodríguez, Joaquín; Rodríguez Martínez, Xavier; Marín i Vivó, Gemma; Paunellas Albert, Josep

    2008-10-01

    To be bedridden reduces one's capacity to move and produces muscular debility that affects the respiratory system leading to a decreased effectiveness in expectoration, the ability to spit up sputum. The pulmonary therapy system integrated in a bed is the result of applying motorized elements to the articulation points of the bad in order to achieve safe positions at therapeutic angles, which improve the breathing-perfusion (blood flow) relationship. This system also makes it possible to apply vibration waves to the patient which favor the elimination of bronchial-pulmonary secretions, the rehabilitation of the bedridden patient and decrease the work load for nursing personnel.

  18. Classifying bed inclination using pressure images.

    Science.gov (United States)

    Baran Pouyan, M; Ostadabbas, S; Nourani, M; Pompeo, M

    2014-01-01

    Pressure ulcer is one of the most prevalent problems for bed-bound patients in hospitals and nursing homes. Pressure ulcers are painful for patients and costly for healthcare systems. Accurate in-bed posture analysis can significantly help in preventing pressure ulcers. Specifically, bed inclination (back angle) is a factor contributing to pressure ulcer development. In this paper, an efficient methodology is proposed to classify bed inclination. Our approach uses pressure values collected from a commercial pressure mat system. Then, by applying a number of image processing and machine learning techniques, the approximate degree of bed is estimated and classified. The proposed algorithm was tested on 15 subjects with various sizes and weights. The experimental results indicate that our method predicts bed inclination in three classes with 80.3% average accuracy.

  19. Gruppebaseret behandling af BED - et faseopdelt behandlingstilbud

    DEFF Research Database (Denmark)

    Laust, Jakob; Lau, Marianne Engelbrecht; Waaddegaard, Mette

    2015-01-01

    Titel: Afrapportering vedr. SATS-puljemidler til behandling og erfaringsopsamling vedr. BED for perioden 1. marts 2013 – 1. maj 2015. Baggrund: Binge Eating Disorder (BED), på dansk tvangsoverspisning, er en udbredt, men overset spiseforstyrrelse med alvorlige psykiske, fysiske og sociale...... konsekvenser. BED blev i 2013 optaget i DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) som en selvstændig diagnose og BED forventes medtaget i den forestående revision af det internationale diagnose system, ICD-11. Sundhedsstyrelsen gav på denne baggrund satspuljemidler til erfaringsopsamling...... vedr. BED. I den forbindelse ansøgte Ambulatorium for Spiseforstyrrelser på Psykoterapeutisk Center Stolpegård ovenstående midler til at udvikle en ambulant, primært psykoterapeutisk gruppebehandling til patienter med moderat til svær BED med fokus på såvel spiseforstyrrelse såvel som overvægt. Metode...

  20. Fluid-bed process for SYNROC production

    International Nuclear Information System (INIS)

    SYNROC is a titanate-based ceramic waste developed for the immobilization of high-level nuclear reactor waste. Lawrence Livermore National Laboratory (LLNL) has investigated a fluid-bed technique for the large-scale production of SYNROC precursor powders. Making SYNROC in a fluid bed permits slurry drying, calcination and reduction-oxidation reactions to be carried out in a single unit. We present the results of SYNROC fluid-bed studies from two fluid-bed units 10 cm in diameter: an internally heated fluid-bed unit developed by Exxon Idaho and an externally heated unit constructed at LLNL. Bed operation over a range of temperatures, feed rates, fluidizing rates, and redox conditions indicate that SYNROC powders of a high density and a uniform particle size can be produced. These powders facilitate the densification step and yield dense ceramics (greater than 95% theoretical density) with well-developed phases and low leaching rates