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Sample records for strongly alkaline fluidized

  1. Application of a fluidized bed reactor charged with aragonite for control of alkalinity, pH and carbon dioxide in marine recirculating aquaculture systems

    Science.gov (United States)

    Paul S Wills, PhD; Pfeiffer, Timothy; Baptiste, Richard; Watten, Barnaby J.

    2016-01-01

    Control of alkalinity, dissolved carbon dioxide (dCO2), and pH are critical in marine recirculating aquaculture systems (RAS) in order to maintain health and maximize growth. A small-scale prototype aragonite sand filled fluidized bed reactor was tested under varying conditions of alkalinity and dCO2 to develop and model the response of dCO2 across the reactor. A large-scale reactor was then incorporated into an operating marine recirculating aquaculture system to observe the reactor as the system moved toward equilibrium. The relationship between alkalinity dCO2, and pH across the reactor are described by multiple regression equations. The change in dCO2 across the small-scale reactor indicated a strong likelihood that an equilibrium alkalinity would be maintained by using a fluidized bed aragonite reactor. The large-scale reactor verified this observation and established equilibrium at an alkalinity of approximately 135 mg/L as CaCO3, dCO2 of 9 mg/L, and a pH of 7.0 within 4 days that was stable during a 14 day test period. The fluidized bed aragonite reactor has the potential to simplify alkalinity and pH control, and aid in dCO2 control in RAS design and operation. Aragonite sand, purchased in bulk, is less expensive than sodium bicarbonate and could reduce overall operating production costs.

  2. Production of bio-oil with low contents of copper and chlorine by fast pyrolysis of alkaline copper quaternary-treated wood in a fluidized bed reactor

    International Nuclear Information System (INIS)

    Koo, Won-Mo; Jung, Su-Hwa; Kim, Joo-Sik

    2014-01-01

    Fast pyrolysis of ACQ (alkaline copper quaternary)-treated wood was carried out in a bench-scale pyrolysis plant equipped with a fluidized bed reactor and char separation system. This study focused on the production of a bio-oil with low copper and chlorine contents, especially by adopting the fractional condensation of bio-oil using water condensers, an impact separator and an electrostatic precipitator. In addition, various analytical tools were applied to investigate the physicochemical properties of the pyrolysis products and the behavior of the preservative during pyrolysis. The bio-oil yield was maximized at 63.7 wt% at a pyrolysis temperature of 411 °C. Highly water-soluble holocellulose-derived components such as acetic acid and hydroxyacetone were mainly collected by the condensers, while lignin-derived components and levoglucosan were mainly observed in the oils collected by the impact separator and electrostatic precipitator. All the bio-oils produced in the experiments were almost free of copper and chlorine. Most copper in ACQ was transferred into the char. - Highlights: • ACQ(alkaline copper quaternary)-treated wood was successfully pyrolyzed in a bench-scale fluidized bed. • Bio-oils separately collected were different in their characteristics. • Bio-oils were free of didecyldimethylammonium chloride. • Bio oils were almost free of copper and chlorine. • The concentration of levoglucosan in a bio-oil was 24–31 wt%

  3. 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

  4. Micelle formation during extraction of alkali elements from strongly alkaline mediums

    International Nuclear Information System (INIS)

    Apanasenko, V.V.; Reznik, A.M.; Bukin, V.I.; Brodskaya, A.V.

    1988-01-01

    Extraction of potassium, rubidium and cesium by phenol reagents in hydrocarbon solvents from strongly alkakine solutions was considered. Tendency of prepared alkali metal phenolates to form micelles in aqueous and organic phases was revealed. Phenolates tendency to form micelles is dictated mainly by the size and position of hydrocarbon substituent in molecule. It is shown that when micelles form in organic phase, alkali elements can be extracted both according to cation-exchange mechanism and according to micellar one. It is noted that alkai element extraction from strongly alkaline media requires the correct choice of extractant: alkali metal phenolate shouldn't form micelles in aqueous solution. n-Alkyl- and arylphenoldisulfides and polysulfides are most preferable for solvent extraction among considered phenol derivatives

  5. Multidimensionality in Fluidized Nanopowder Agglomerates

    NARCIS (Netherlands)

    De Martin, L.; Bouwman, W.G.; Van Ommen, J.R.

    2013-01-01

    recent years, the interest in fluidization as a mean to process nanoparticles is strongly increasing. Due to the small size of the nanoparticles, which makes van der Waals forces predominate, they do not fluidize as single particles but as agglomerates. Various researchers using settling experiments

  6. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber

    OpenAIRE

    Cao, Ting-Ting; Wang, Yuan-Jing; Zhang, Yu-Qing

    2013-01-01

    Strongly alkaline electrolyzed water (SAEW) was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+) concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V) for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile prope...

  7. Performance and application of a fluidized bed limestone reactor designed for control of alkalinity, hardness and pH at the Warm Springs Regional Fisheries Center

    Science.gov (United States)

    Springs serving the Warm Springs Regional Fisheries Center, Warm Springs, Georgia, have pH, alkalinity, and hardness levels that lie under the range required for successful fish propagation while free CO2 is well above allowable targets. We evaluate a pretreatment process that exploits limestone's (...

  8. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Cao

    Full Text Available Strongly alkaline electrolyzed water (SAEW was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+ concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile properties and thermal decomposition temperature of a single filament of silk fibroin obtained by the SAEW method were almost the same as those for the fiber obtained by the neutral soap, and much higher than those for the fiber obtained by Na2CO3 degumming. The results demonstrate that SAEW is an environmentally friendly and pollution-free silk degumming agent that allows highly efficient, low cost recovery of sericin.

  9. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber.

    Science.gov (United States)

    Cao, Ting-Ting; Wang, Yuan-Jing; Zhang, Yu-Qing

    2013-01-01

    Strongly alkaline electrolyzed water (SAEW) was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+) concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V) for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile properties and thermal decomposition temperature of a single filament of silk fibroin obtained by the SAEW method were almost the same as those for the fiber obtained by the neutral soap, and much higher than those for the fiber obtained by Na2CO3 degumming. The results demonstrate that SAEW is an environmentally friendly and pollution-free silk degumming agent that allows highly efficient, low cost recovery of sericin.

  10. A Strongly Calc-alkaline Suite in the Midst of the Tholeiitic Columbia River Basalt Province: Implications for Generating the Calc-alkaline Trend Without Subduction Processes

    Science.gov (United States)

    Steiner, A. R.; Streck, M. J.

    2012-12-01

    The mid-Miocene lavas of the Strawberry Volcanics (SV), distributed over 3,400 km2 in NE Oregon, comprise a diverse volcanic suite, which span the range of compositions from basalt to rhyolite. The volcanic suite is mainly composed of calc-alkaline (CA) basaltic andesite and andesite, yet tholeiitic (TH) lavas of basalt to andesite occur as well. The SV lies in the heart of nearly coeval flood basalts of the Columbia River province of the Pacific Northwest. The unique combination of strongly CA rocks of the SV in a non-subduction setting provide an excellent opportunity to study controls on inducing CA evolution in the midst of a TH province and independent of processes taking places at an active subduction zone. New 40Ar/39Ar ages indicate CA basaltic andesites to andesites of the SV erupted at least from 14.78±0.13 Ma to 12.44±0.12 Ma demonstrating that CA magmatism of the SV was ongoing during the eruptions of the tholeiitic Wanapum Basalt member of the Columbia River Basalt Group (CRBG). This range will likely be extended to even older ages in the future because existent age dates did not include samples from near the base of the SV. Thickness of intermediate lavas flows of the SV range from 15 m to as thin as 2 m and lavas are characterized by mostly phenocryst poor lithologies. When phenocrysts are abundant they are very small suggesting growth late during eruption. Single lava flow sections can include on the order of 30 conformable flows, testifying to a vigorous eruption history. The thickest andesitic sections are located in the glacially carved mountains of the Strawberry Mountain Wilderness (i.e. Strawberry Mountain, High Lake, and Slide Lake) where several vent complexes are exposed, which are delineated by dikes and plugs with finely interlocking plutonic textures, cross-cutting SV lava flows. Dikes generally strike NW-SE. Subtle variations in major and trace element compositions exist between TH and CA lavas of the SV. The CA lavas of the SV are

  11. Fluidization quality analyzer for fluidized beds

    Science.gov (United States)

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

    1995-07-25

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

  12. Multidimensionality in fluidized nanopowder agglomerates

    Science.gov (United States)

    Martín, Lilian de; Bouwman, Wim G.; van Ommen, J. Ruud

    2013-06-01

    In recent years, the interest in fluidization as a mean to process nanoparticles is strongly increasing. Due to the small size of the nanoparticles, which makes van der Waals forces predominate, they do not fluidize as single particles but as agglomerates. Various researchers using settling experiments and bed expansion measurements conclude that fluidized agglomerates are fractal structures with a single fractal dimension of 2.5. Based on microscopy results, Wang et al. ``Powder Technology 124, 152-C159 (2002)'' propose a hierarchical structure, which seems in contradiction with the use of only one fractal dimension as a descriptor of the whole structure. Moreover, it is not clear whether the structure presented by the agglomerates ex-situ is the same during fluidization. Hence, in this work we have characterized in-situ the internal structure of fluidized agglomerates by means of spin-echo small-angle neutron scattering (SESANS). We show that the structure of the agglomerates present at least two fractal dimensions. One of them is ~= 2.1 and characterizes the primary strong agglomerates. The second one is ~= 2.8 and characterizes the larger agglomerates formed by the primary agglomerates.

  13. On partial fluidization in rotating fluidized beds

    International Nuclear Information System (INIS)

    Kao, J.; Pfeffer, R.; Tardos, G.I.

    1987-01-01

    In a rotating fluidized bed, unlike in a conventional fluidized bed, the granules are fluidized layer by layer from the (inner) free surface outward at increasing radius as the gas velocity is increased. This is a very significant and interesting phenomenon and is extremely important in the design of these fluidized beds. The phenomenon was first suggested in a theoretical analysis and recently verified experimentally in the authors' laboratory. However, in the first paper, the equations presented are too cumbersome and the influence of bed thickness is not clearly stated. In this note the authors present simplified equations, based on that paper, for the pressure drop and the minimum fluidizing velocities in a rotating fluidized bed. Experimental data are also shown and compared with the theoretical model, and the effect of bed thickness is shown. Furthermore, an explanation for the observation of a maximum in the pressure drop vs. velocity curve instead of the plateau derived by Chen is proposed

  14. Gas back-mixing studies in membrane assisted bubbling fluidized beds

    NARCIS (Netherlands)

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

    2007-01-01

    Fluidized beds employing fine powders are finding increased application in the chemical and petrochemical industry because of their excellent mass and heat transfer characteristics. However, in fluidized bed chemical reactors axial gas back mixing can strongly decrease the conversion and

  15. Fluidization of spherocylindrical particles

    Directory of Open Access Journals (Sweden)

    Mahajan Vinay V.

    2017-01-01

    Full Text Available Multiphase (gas-solid flows are encountered in numerous industrial applications such as pharmaceutical, food, agricultural processing and energy generation. A coupled computational fluid dynamics (CFD and discrete element method (DEM approach is a popular way to study such flows at a particle scale. However, most of these studies deal with spherical particles while in reality, the particles are rarely spherical. The particle shape can have significant effect on hydrodynamics in a fluidized bed. Moreover, most studies in literature use inaccurate drag laws because accurate laws are not readily available. The drag force acting on a non-spherical particle can vary considerably with particle shape, orientation with the flow, Reynolds number and packing fraction. In this work, the CFD-DEM approach is extended to model a laboratory scale fluidized bed of spherocylinder (rod-like particles. These rod-like particles can be classified as Geldart D particles and have an aspect ratio of 4. Experiments are performed to study the particle flow behavior in a quasi-2D fluidized bed. Numerically obtained results for pressure drop and bed height are compared with experiments. The capability of CFD-DEM approach to efficiently describe the global bed dynamics for fluidized bed of rod-like particles is demonstrated.

  16. Fluidization of spherocylindrical particles

    Science.gov (United States)

    Mahajan, Vinay V.; Nijssen, Tim M. J.; Fitzgerald, Barry W.; Hofman, Jeroen; Kuipers, Hans; Padding, Johan T.

    2017-06-01

    Multiphase (gas-solid) flows are encountered in numerous industrial applications such as pharmaceutical, food, agricultural processing and energy generation. A coupled computational fluid dynamics (CFD) and discrete element method (DEM) approach is a popular way to study such flows at a particle scale. However, most of these studies deal with spherical particles while in reality, the particles are rarely spherical. The particle shape can have significant effect on hydrodynamics in a fluidized bed. Moreover, most studies in literature use inaccurate drag laws because accurate laws are not readily available. The drag force acting on a non-spherical particle can vary considerably with particle shape, orientation with the flow, Reynolds number and packing fraction. In this work, the CFD-DEM approach is extended to model a laboratory scale fluidized bed of spherocylinder (rod-like) particles. These rod-like particles can be classified as Geldart D particles and have an aspect ratio of 4. Experiments are performed to study the particle flow behavior in a quasi-2D fluidized bed. Numerically obtained results for pressure drop and bed height are compared with experiments. The capability of CFD-DEM approach to efficiently describe the global bed dynamics for fluidized bed of rod-like particles is demonstrated.

  17. Fluidized bed incinerator development

    International Nuclear Information System (INIS)

    Ziegler, D.L.; Johnson, A.J.

    1976-01-01

    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

  18. Influence of Experimental Parameters Using the Dip-Coating Method on the Barrier Performance of Hybrid Sol-Gel Coatings in Strong Alkaline Environments

    Directory of Open Access Journals (Sweden)

    Rita B. Figueira

    2015-04-01

    Full Text Available Previous studies have shown that the barrier effect and the performance of organic-inorganic hybrid (OIH sol-gel coatings are highly dependent on the coating deposition method as well as on the processing conditions. However, studies on how the coating deposition method influences the barrier properties in alkaline environments are scarce. The aim of this experimental research was to study the influence of experimental parameters using the dip-coating method on the barrier performance of an OIH sol-gel coating in contact with simulated concrete pore solutions (SCPS. The influence of residence time (Rt, a curing step between each dip step and the number of layers of sol-gel OIH films deposited on hot-dip galvanized steel to prevent corrosion in highly alkaline environments was studied. The barrier performance of these OIH sol-gel coatings, named U(400, was assessed in the first instants of contact with SCPS, using electrochemical impedance spectroscopy and potentiodynamic methods. The durability and stability of the OIH coatings in SCPS was monitored during eight days by macrocell current density. The morphological characterization of the surface was performed by Scanning Electronic Microscopy before and after exposure to SCPS. Glow Discharge Optical Emission Spectroscopy was used to investigate the thickness of the U(400 sol-gel coatings as a function of the number of layers deposited with and without Rt in the coatings thickness.

  19. Fluidized-bed nuclear reactor

    International Nuclear Information System (INIS)

    Grimmett, E.S.; Kunze, J.F.

    1975-01-01

    A reactor vessel containing a fluidized-bed region of particulate material including both a neutron-moderating and a fertile substance is described. A gas flow including fissile material passes through the vessel at a sufficient rate to fluidize the particulate material and at a sufficient density to support a thermal fission reaction within the fluidized-bed region. The high-temperature portion of a heat transfer system is located within the fluidized-bed region of the reactor vessel in direct contact with the fluidized particles. Heat released by fission is thereby transferred at an enhanced rate to a coolant circulating within the heat transfer system. Fission products are continuously removed from the gas flow and supplemental fissile material added during the reactor operation. (U.S.)

  20. Mixed-potential Behavior of Nanostructured RuO2 Sensing Electrode of Water Quality Sensors in Strong Alkaline Solutions at a Temperature Range of 9-30° C

    Science.gov (United States)

    Zhuiykov, Serge

    2009-05-01

    Mixed-potential behavior of the water quality monitoring sensors using nanostructured RuO2 sensing electrode (SE) has been observed in strong alkaline solutions at dissolved oxygen (DO) measurements in the temperature range of 9-30° C. This behavior indicated that a Faradaic oxygen reduction reaction becomes not only a one-electron process, which is typical for DO measurements at a neutral pH, but rather multi-step process with superoxide oxygen ions (O2-), OH- and RuO42- ions involvement. The DO sensing characteristics were examined in the pH range of 2.0-13.0. The measured emf at strong alkaline solutions is a mixed potential from the reactions involved RuO42- and OH- ions and DO. Impedance spectroscopy was employed for confirmation the mixed-potential behavior of the sensor. It was also found during experiments that OH- ions influence the response/recovery rate of the SE reactions as the pH of water increases.

  1. Pyrolysis of corncobs at fluidization

    Energy Technology Data Exchange (ETDEWEB)

    Hongming Jiang; Morey, R.V. (Minnesota Univ., St. Paul, MN (United States). Dept. of Agricultural Engineering)

    1992-01-01

    Pyrolysis of corncob particles was conducted in nitrogen in an externally heated benchscale fluidized bed reactor. Test results are presented with a demonstration of their application in gasification modelling. (author).

  2. Apparatus and process for controlling fluidized beds

    Science.gov (United States)

    Rehmat, Amirali G.; Patel, Jitendra G.

    1985-10-01

    An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

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

    Science.gov (United States)

    Lim, Eldin Wee Chuan

    2017-11-01

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

  4. IEN project - Fluidized bed burner

    International Nuclear Information System (INIS)

    1985-08-01

    Due to difficulties inherent to the organic waste storage from laboratories and institutes which use radioactive materials for scientific researches, the Nuclear Facilities Division (DIN/CNEN); elaborated a project for constructing a fluidized burner, in laboratory scale, for burning the low level organic radioactive wastes. The burning system of organic wastes is described. (M.C.K.) [pt

  5. Fluidization of Dried Wastewater Sludge.

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Pohořelý, Michael; Trnka, Otakar

    2007-01-01

    Roč. 178, 3 (2007) , s. 166-172 ISSN 0032-5910 R&D Projects: GA AV ČR(CZ) IAA4072201 Institutional research plan: CEZ:AV0Z40720504 Keywords : fluidization characteristics * multiphase reactors * dried stabilized wastewater sludge Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.130, year: 2007

  6. The Rheology of Acoustically Fluidized Sand

    Science.gov (United States)

    Conrad, J. W.; Melosh, J.

    2013-12-01

    The collapse of large craters and the formation of central peaks and peak rings is well modeled by numerical computer codes that incorporate the acoustic fluidization mechanism to temporarily allow the fluid-like flow of rock debris immediately after crater excavation. Furthermore, long runout landslides require a similar mechanism to explain their almost frictionless movement, which is probably also a consequence of their granular composition coupled with internal vibrations. Many different investigators have now confirmed the ability of vibrations to fluidize granular materials. Yet it still remains to fully describe the rheology of vibrated sand as a function of stress, frequency and amplitude of the vibrations in the sand itself. We constructed a rotational viscometer to quantitatively investigate the relation between the stress and strain rate in a horizontal bed of strongly vibrated sand. In addition to the macroscopic stain rate, the amplitude and frequency of the vibrations produced by a pair of pneumatic vibrators were also measured with the aid of miniaturized piezoelectric accelerometers (B&K 4393) whose output was recorded on a digital storage oscilloscope. The initial gathering of the experimental data was difficult due to granular memory, but by having the sand compacted vibrationally for 8 minutes before each run the scatter of data was reduced and we were able to obtain consistent results. Nevertheless, our major source of uncertainty was variations in strain rate from run to run. We find that vibrated sand flows like a highly non-Newtonian fluid, in which the shear strain rate is proportional to stress to a power much greater than one, where the precise power depends on the amplitude and frequency of the applied vibrations. Rapid flow occurs at stresses less than half of the static yield stress (that is, the yield stress when no vibration is applied) when strong vibrations are present. For a Newtonian fluid, such as water, the relation between

  7. Advances in fluidized bed technologies

    International Nuclear Information System (INIS)

    Mutanen, K.

    1992-01-01

    Atmospheric fluidized bed combustion (AFBC) has advanced into industrial cogeneration and utility-scale electric generation. During the 1980's AFBC became the dominant technology in the United States for power generation systems fired with solid fuels. Development of pressurized fluidized bed combustion/gasification (PFB/G) has grown rapidly from small bench-scale rigs to large pilot and demonstration plants. AFBC as large as 160 MWe in capacity are now in operation, while pressurized combustion systems generating 80 MWe have started up two years ago. The major driving forces behind development of fluidized bed technologies are all the time strictening emission control regulations, need for fuel flexibility, repowering of older power plants and need for higher efficiency in electricity generation. Independent power producers (IPP) and cogenerators were the first ones in the United States who accepted AFBC for wide commercial use. Their role will be dominant in the markets of the 1990's also. Developers of AFBC systems are working on designs that reduce investment costs, decrease emissions and offer even higher reliability and availability in utility-scale applications while developers of PFBC/G work on designs that increase plant efficiencies, allow modular construction, decrease emissions further and reduce the cost of generating power. This paper presents technological background, commercial status, boiler performance, emissions and future developments for both AFBC and PFBC/G systems

  8. Effect of compaction history on the fluidization behavior of fine cohesive powders

    Science.gov (United States)

    Valverde, Jose Manuel; Castellanos, Antonio

    2006-05-01

    Fine particles agglomerate in the fluidized state due to the strength of interparticle attractive forces as compared to particle weight. Interparticle adhesion can be largely increased by consolidation stresses applied during powder handling. As a consequence, fragments of the consolidated powder may persist when the powder is fluidized, which gives rise to large agglomerates of strongly adhered particles in fluidization. This history-dependent effect can be minimized by coating the particles with surface additives such as silica nanoparticles. In this paper, we investigate the effect of high consolidation stresses σc previously applied to samples of silica-coated fine particles on their fluidization behavior. Our experimental measurements show that, even though homogeneous fluidization is still observed, the average agglomerate size and fractal dimension of the agglomerates increase as σc is increased. Bed expansion in the fluidized state is hindered by previously applied high consolidations, which we attribute to an increase of the largest stable size of mesoscopic fluid pockets. As a consequence, we observe that the initiation of macroscopic bubbling is delayed up to larger values of the fluid velocity.

  9. Flue Gas Emissions from Fluidized Bed Combustion

    NARCIS (Netherlands)

    Bramer, E.A.; Valk, M.

    1995-01-01

    During the past decades fluidized bed coal combustion was developed as a technology for burning coal in an effective way meeting the standards for pollution control. During the earlier years of research on fluidized bed combustion, the potential for limiting the S02 emission by adding limestone to

  10. Fluidized bed silicon deposition from silane

    Science.gov (United States)

    Hsu, George (Inventor); Levin, Harry (Inventor); Hogle, Richard A. (Inventor); Praturi, Ananda (Inventor); Lutwack, Ralph (Inventor)

    1984-01-01

    A process and apparatus for thermally decomposing silicon containing gas for deposition on fluidized nucleating silicon seed particles is disclosed. Silicon seed particles are produced in a secondary fluidized reactor by thermal decomposition of a silicon containing gas. The thermally produced silicon seed particles are then introduced into a primary fluidized bed reactor to form a fludized bed. Silicon containing gas is introduced into the primary reactor where it is thermally decomposed and deposited on the fluidized silicon seed particles. Silicon seed particles having the desired amount of thermally decomposed silicon product thereon are removed from the primary fluidized reactor as ultra pure silicon product. An apparatus for carrying out this process is also disclosed.

  11. Continuous austempering fluidized bed furnace. Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-23

    The intended objective of this project was to show the benefits of using a fluidized bed furnace for austenitizing and austempering of steel castings in a continuous manner. The division of responsibilities was as follows: (1) design of the fluidized bed furnace--Kemp Development Corporation; (2) fabrication of the fluidized bed furnace--Quality Electric Steel, Inc.; (3) procedure for austempering of steel castings, analysis of the results after austempering--Texas A and M University (Texas Engineering Experiment Station). The Department of Energy provided funding to Texas A and M University and Kemp Development Corporation. The responsibility of Quality Electric Steel was to fabricate the fluidized bed, make test castings and perform austempering of the steel castings in the fluidized bed, at their own expense. The project goals had to be reviewed several times due to financial constraints and technical difficulties encountered during the course of the project. The modifications made and the associated events are listed in chronological order.

  12. Environmental remediation with products of fluidized bed combustion

    International Nuclear Information System (INIS)

    Kim, A.G.

    1999-01-01

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

  13. Tar removal during the fluidized bed gasification of plastic waste.

    Science.gov (United States)

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

    2009-02-01

    A recycled polyethylene was fed in a pilot plant bubbling fluidized bed gasifier, having an internal diameter of 0.381 m and a maximum feeding capacity of 90 kg/h. The experimental runs were carried out under various operating conditions: the bed temperature was kept at about 850 degrees C, the equivalence ratio varied between 0.2 and 0.35, the amount of bed material was between 131 and 215 kg, the fluidizing velocity was between 0.5 and 0.7 m/s, quartz sand and olivine were used as bed material, and air and steam were used as fluidizing reactants. The results confirm that the tar removal treatments applied inside the gasifier (primary methods) can eliminate or strongly reduce the need for a further downstream cleanup of the syngas. In particular, the utilization of a natural olivine as an in situ tar reduction agent remarkably improves the quality of the product gas, in terms of both high hydrogen volumetric fraction and larger syngas yield.

  14. Heat and mass transfer enforcement of vibrating fluidized bed

    Science.gov (United States)

    Chu, Zhide; Yang, Junhong; Li, Xuhui; Song, Yang

    1994-12-01

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

  15. Characterization of fluidization regime in circulating fluidized bed reactor with high solid particle concentration using computational fluid dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Chalermsinsuwan, Benjapon; Thummakul, Theeranan; Piumsomboon, Pornpote [Chulalongkorn University, Bangkok (Thailand); Gidaspow, Dimitri [Armour College of Engineering, Chicago (United States)

    2014-02-15

    The hydrodynamics inside a high solid particle concentration circulating fluidized bed reactor was investigated using computational fluid dynamics simulation. Compared to a low solid particle reactor, all the conventional fluidization regimes were observed. In addition, two unconventional fluidization regimes, circulating-turbulent and dense suspension bypassing regimes, were found with only primary gas injection. The circulating-turbulent fluidization regime showed uniformly dense solid particle distribution in all the system directions, while the dense suspension bypassing fluidization regime exhibited the flow of solid particles at only one side system wall. Then, comprehensive fluidization regime clarification and mapping were evaluated using in-depth system parameters. In the circulating-turbulent fluidization regime, the total granular temperature was low compared to the adjacent fluidization regimes. In the dense suspension bypassing fluidization regime, the highest total granular temperature was obtained. The circulating-turbulent and dense suspension bypassing fluidization regimes are suitable for sorption and transportation applications, respectively.

  16. Recent advances in fluidized bed drying

    Science.gov (United States)

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

    2017-09-01

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

  17. Fluidization calculation on nuclear fuel kernel coating

    International Nuclear Information System (INIS)

    Sukarsono; Wardaya; Indra-Suryawan

    1996-01-01

    The fluidization of nuclear fuel kernel coating was calculated. The bottom of the reactor was in the from of cone on top of the cone there was a cylinder, the diameter of the cylinder for fluidization was 2 cm and at the upper part of the cylinder was 3 cm. Fluidization took place in the cone and the first cylinder. The maximum and the minimum velocity of the gas of varied kernel diameter, the porosity and bed height of varied stream gas velocity were calculated. The calculation was done by basic program

  18. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D

    1999-01-01

    Highly capacitive (high surface area) electrodes that are electrochemically stable in strong alkaline electrolyte will form the basis for a new generation of electrical and electrochemical energy storage and conversion devices...

  19. Fluidization technologies: Aerodynamic principles and process engineering.

    Science.gov (United States)

    Dixit, Rahul; Puthli, Shivanand

    2009-11-01

    The concept of fluidization has been adapted to different unit processes of pharmaceutical product development. Till date a lot of improvements have been made in the engineering design to achieve superior process performance. This review is focused on the fundamental principles of aerodynamics and hydrodynamics associated with the fluidization technologies. Fluid-bed coating, fluidized bed granulation, rotor processing, hot melt granulation, electrostatic coating, supercritical fluid based fluidized bed technology are highlighted. Developments in the design of processing equipments have been explicitly elucidated. This article also discusses processing problems from the operator's perspective along with latest developments in the application of these principles. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association

  20. Lipid encapsulated phenolic compounds by fluidization

    Science.gov (United States)

    Phenolic compounds exhibit antioxidant and antimicrobial activities with applications as functional food and feed additives. Ferulic acid, a phenolic compound present in grain crops and lignocellulose biomass, was encapsulated with saturated triglycerides using a laboratory fluidizer. Stability of t...

  1. Pulsed atmospheric fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

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

  2. Fluidized-bed reactors processes and operating conditions

    CERN Document Server

    Yates, John G

    2016-01-01

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

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

    DEFF Research Database (Denmark)

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

    1997-01-01

    The flow pattern of a fluidized bed with non-fluidized zones is investigated both experimentally and theoretically. Experiments were carried out in such a way that air was introduced only through part of the distributor. The results show a significant amount of air flowing to the zone where no ai...

  4. Fluidization of Group B particles with a rotating distributor

    OpenAIRE

    Sobrino Fernández, Celia; Almendros Ibáñez, José Antonio; Santana Santana, Domingo José; Vega Blázquez, Mercedes de

    2008-01-01

    A novel rotating distributor fluidized bed is presented. The distributor is a rotating perforated plate, with 1% open-area ratio. This work evaluates the performance of this new design, considering pressure drop, Δp, and quality of fluidization. Bed fluidization was easily achieved with the proposed device, improving the solid mixing and the quality of fluidization. In order to examine the effect of the rotational speed of the distributor plate on the hydrodynamic behavior of the bed...

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  6. Fluidized bed selective pyrolysis of coal

    Science.gov (United States)

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

    1992-12-15

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

  7. Analysis of circulating fluidized bed combustion technology

    Energy Technology Data Exchange (ETDEWEB)

    Furusawa, Takehiko; Shimizu, Tadaaki; Yang, Guilin

    1987-05-20

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

  8. Gas filtration in binary fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-12-01

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

  9. Modelling of Devolatilization in Fluidized Bed Combustion

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  10. Fluidized bed electrowinning of copper. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    The objectives of the study were to: design and construct a 10,000- amp fluidized bed electrowinning cell for the recovery of copper from acidic sulfate solutions; demonstrate the technical feasibility of continuous particle recirculation from the electrowinning cell with the ultimate goal of continuous particle removal; and measure cell efficiency as a function of operating conditions.

  11. Fluidized-Bed Silane-Decomposition Reactor

    Science.gov (United States)

    Iya, Sridhar K.

    1991-01-01

    Fluidized-bed pyrolysis reactor produces high-purity polycrystalline silicon from silane or halosilane via efficient heterogeneous deposition of silicon on silicon seed particles. Formation of silicon dust via homogeneous decomposition of silane minimized, and deposition of silicon on wall of reactor effectively eliminated. Silicon used to construct solar cells and other semiconductor products.

  12. Bubble Swarm Rise Velocity in Fluidized Beds.

    Czech Academy of Sciences Publication Activity Database

    Punčochář, Miroslav; Růžička, Marek; Šimčík, Miroslav

    2016-01-01

    Roč. 152, OCT 2 (2016), s. 84-94 ISSN 0009-2509 R&D Projects: GA ČR(CZ) GA15-05534S Institutional support: RVO:67985858 Keywords : bubbling fluidized bed * gas-solid * bubble swarm velocity Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.895, year: 2016

  13. Fluidization Behavior of Oil-Contaminated Sand.

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Trnka, Otakar; Pohořelý, Michael

    2007-01-01

    Roč. 61, 2 (2007) , s. 93-97 ISSN 0366-6352 R&D Projects: GA AV ČR(CZ) IAA4072201 Institutional research plan: CEZ:AV0Z40720504 Keywords : fluidized bed * hydrodynamics * oil pollution Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.367, year: 2007

  14. Anodes for alkaline electrolysis

    Science.gov (United States)

    Soloveichik, Grigorii Lev [Latham, NY

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  15. Alkaline "Permanent" Paper.

    Science.gov (United States)

    Pacey, Antony

    1991-01-01

    Discussion of paper manufacturing processes and their effects on library materials focuses on the promotion of alkaline "permanent" paper, with less acid, by Canadian library preservation specialists. Standards for paper acidity are explained; advantages of alkaline paper are described, including decreased manufacturing costs; and…

  16. 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

  17. 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.

  18. 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

  19. In-situ treatment of acid mine waters using fluidized bed ash: Field study

    International Nuclear Information System (INIS)

    Everett, J.W.; Canty, G.A.

    1999-01-01

    A slurry of mine water and fluidized bed ash (FBA) was injected into an abandoned coal mine in eastern Oklahoma in July 1997. Oil-field technology was used to inject 1.8 Gg (418 tons) of FBA through five wells in 15 hours. Prior to injection the seep water had a pH of 4.4, was net acidic (acidity over 400 mg/L as CaCO 3 ), and had relatively high metal concentrations (in mg/L: Fe-200; Mn-7; and Al-6). After injection, during the period of effective treatment, the seep water had a pH above 6.0, less net acidity, and had lower metals concentrations (in mg/L: Fe-120; Mn-5; and Al-< PQL). When the treated seep water exited the mine, the dissolved metals oxidized and hydrolyzed. As the metals precipitated, the alkalinity introduced by the FBA was consumed and the pH dropped. However, the seep water characteristics upon entering the receiving stream were improved, compared to pre-injection. The resulting seep water quality is such that it is more amenable to further treatment by passive treatment methods, such as anoxic limestone drains or wetlands. Alkaline injection is a finite treatment process. Eventually, the added alkalinity is exhausted, at which time the seep returns to pre-injection conditions, necessitating another injection of ash. For the study discussed in this paper, the treatment lasted approximately 15 months. While the amount of alkalinity added to the mine could have potentially treated much more than a year's volume of seep water, it is believed that much of the injected alkalinity was unavailable in backwater areas in the mine. This alkalinity contributed little, if any, to the treatment of water flowing through the mine. Mine hydrology, especially during injection are crucial to treatment longevity

  20. Alkaline battery operational methodology

    Science.gov (United States)

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

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

  2. Update on status of fluidized-bed combustion technology

    International Nuclear Information System (INIS)

    Stallings, J.; Boyd, T.; Brown, R.

    1992-01-01

    During the 1980s, fluidized-bed combustion technology has become the dominant technology for solid-fuel-fired power generation systems in the United States. Atmospheric fluidized beds as large as 160 MWe in capacity are now in operation, while pressurized systems reaching 80 MWe have started up in the last year. The commercial status, boiler performance, emissions, and future developments for both atmospheric and pressurized fluidized-bed combustion systems are discussed

  3. Uranium in alkaline rocks

    International Nuclear Information System (INIS)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential

  4. Uranium in alkaline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

  5. Characterization and quantification of biochar alkalinity.

    Science.gov (United States)

    Fidel, Rivka B; Laird, David A; Thompson, Michael L; Lawrinenko, Michael

    2017-01-01

    Lack of knowledge regarding the nature of biochar alkalis has hindered understanding of pH-sensitive biochar-soil interactions. Here we investigate the nature of biochar alkalinity and present a cohesive suite of methods for its quantification. Biochars produced from cellulose, corn stover and wood feedstocks had significant low-pK a organic structural (0.03-0.34 meq g -1 ), other organic (0-0.92 meq g -1 ), carbonate (0.02-1.5 meq g -1 ), and other inorganic (0-0.26 meq g -1 ) alkalinities. All four categories of biochar alkalinity contributed to total biochar alkalinity and are therefore relevant to pH-sensitive soil processes. Total biochar alkalinity was strongly correlated with base cation concentration, but biochar alkalinity was not a simple function of elemental composition, soluble ash, fixed carbon, or volatile matter content. More research is needed to characterize soluble biochar alkalis other than carbonates and to establish predictive relationships among biochar production parameters and the composition of biochar alkalis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

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

  7. 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

  8. Gas distributor for fluidized bed coal gasifier

    Science.gov (United States)

    Worley, Arthur C.; Zboray, James A.

    1980-01-01

    A gas distributor for distributing high temperature reaction gases to a fluidized bed of coal particles in a coal gasification process. The distributor includes a pipe with a refractory reinforced lining and a plurality of openings in the lining through which gas is fed into the bed. These feed openings have an expanding tapered shape in the downstream or exhaust direction which aids in reducing the velocity of the gas jets as they enter the bed.

  9. Reinforcement versus fluidization in cytoskeletal mechanoresponsiveness.

    Directory of Open Access Journals (Sweden)

    Ramaswamy Krishnan

    Full Text Available Every adherent eukaryotic cell exerts appreciable traction forces upon its substrate. Moreover, every resident cell within the heart, great vessels, bladder, gut or lung routinely experiences large periodic stretches. As an acute response to such stretches the cytoskeleton can stiffen, increase traction forces and reinforce, as reported by some, or can soften and fluidize, as reported more recently by our laboratory, but in any given circumstance it remains unknown which response might prevail or why. Using a novel nanotechnology, we show here that in loading conditions expected in most physiological circumstances the localized reinforcement response fails to scale up to the level of homogeneous cell stretch; fluidization trumps reinforcement. Whereas the reinforcement response is known to be mediated by upstream mechanosensing and downstream signaling, results presented here show the fluidization response to be altogether novel: it is a direct physical effect of mechanical force acting upon a structural lattice that is soft and fragile. Cytoskeletal softness and fragility, we argue, is consistent with early evolutionary adaptations of the eukaryotic cell to material properties of a soft inert microenvironment.

  10. Pressurized Fluidized Bed Combustion of Sewage Sludge

    Science.gov (United States)

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

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

  11. Status of the fluidized bed unit

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  12. Pulsed atmospheric fluidized-bed combustor development

    International Nuclear Information System (INIS)

    1992-05-01

    Pulsed atmospheric fluidized-bed combustion (PAFBC) is a unique and innovative coal-fueled technology that has the potential to meet these conditions and provide heat and/or process steam to small industrial, commercial, institutional and residential complexes. The potential of Pulse Atmospheric Fluidized Bed Combustion (PAFBC) technology has been amply demonstrated under the sponsorship of a previous DOE/METC contract (DE-AC21-88MC25069). The environmental performance of a coal-fired laboratory-scale system (1.5 million British Thermal Units per hour) (MMBtu/hr) significantly surpassed that of conventional bubbling and circulating fluidized-bed combustion units (see Table 1 for performance comparison). Prompted by these encouraging results in combustion, sulfur capture, emissions control, and enhanced heat transfer, Island Creek Coal Company (ICC) and Baltimore Thermal Energy Corporation expressed interest in the technology and offered to participate by providing host sites for field testing. EA's have been submitted independently for each of these field test sites. This submission addresses the preliminary testing of the PAFBC unit at Manufacturing and Technology Conversion International's (MTCI) Baltimore, MD facility

  13. Method for fluidizing and coating ultrafine particles, device for fluidizing and coating ultrafine particles

    Science.gov (United States)

    Li, Jie; Liu, Yung Y

    2015-01-20

    The invention provides a method for dispersing particles within a reaction field, the method comprising confining the particles to the reaction field using a standing wave. The invention also provides a system for coating particles, the system comprising a reaction zone; a means for producing fluidized particles within the reaction zone; a fluid to produce a standing wave within the reaction zone; and a means for introducing coating moieties to the reaction zone. The invention also provides a method for coating particles, the method comprising fluidizing the particles, subjecting the particles to a standing wave; and contacting the subjected particles with a coating moiety.

  14. Fluidized Bed Asbestos Sampler Design and Testing

    Energy Technology Data Exchange (ETDEWEB)

    Karen E. Wright; Barry H. O' Brien

    2007-12-01

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

  15. Exploring the significance of the fluidized flow regime for avalanche hazard mapping

    Science.gov (United States)

    Issler, Dieter; Gauer, Peter

    Observational and experimental evidence suggests that it is important to explicitly account for the fluidized flow regime in avalanche hazard mapping due to its high mobility, intermediate density and high velocity. We explore the differences from conventional runout modelling by implementing an extension of the Norem-Irgens-Schieldrop (NIS) rheology in a simple mass-point model. When the dispersive stresses and the excess pore pressure equal the overburden pressure, the flow height increases and the density diminishes until a new equilibrium is reached, determined by the different density dependencies of the two parameters of the dispersive stresses. Fluidization requires sufficiently steep terrain; when it occurs it leads to substantially higher velocities than compared to the dense-flow regime. The model parameters are strongly constrained by their physical meaning and vary little between widely different avalanches. However, in all test cases we obtained better agreement between simulated and observed runout distances and pressure effects than with conventional models.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

  17. Pressure drop across the distributor in fluidized beds with regular and irregular distributor design

    International Nuclear Information System (INIS)

    Ho, T.C.; Chen, T.K.; Hopper, J.R.

    1984-01-01

    The characteristics of the distributor pressure drop in a fluidized bed corresponding to perforated distributor plates with regular and irregular distributor design were studied. Distributor pressure drops were measured in an empty bed and beds with different fluidizing particles or bed heights. The design variables tested included the open area ratio, hole size, hole lay-out, plate thickness and design irregularity. The characteristics of distributor pressure drop corresponding to abnormal operating conditions, i.e., hole blocking and channeling, were also examined. The results indicate that the open area ratio is the most critical parameter governing the plate pressure drop for a regular distributor and that the design irregularity has a strong effect on the distributor behavior when particles are present. The study has given rise to a criterion for uniform air distribution across the distributor holes

  18. Alkaline phosphatase: an overview.

    Science.gov (United States)

    Sharma, Ujjawal; Pal, Deeksha; Prasad, Rajendra

    2014-07-01

    Alkaline phosphatase (ALP; E.C.3.I.3.1.) is an ubiquitous membrane-bound glycoprotein that catalyzes the hydrolysis of phosphate monoesters at basic pH values. Alkaline phosphatase is divided into four isozymes depending upon the site of tissue expression that are Intestinal ALP, Placental ALP, Germ cell ALP and tissue nonspecific alkaline phosphatase or liver/bone/kidney (L/B/K) ALP. The intestinal and placental ALP loci are located near the end of long arm of chromosome 2 and L/B/K ALP is located near the end of the short arm of chromosome 1. Although ALPs are present in many mammalian tissues and have been studied for the last several years still little is known about them. The bone isoenzyme may be involved in mammalian bone calcification and the intestinal isoenzyme is thought to play a role in the transport of phosphate into epithelial cells of the intestine. In this review, we tried to provide an overview about the various forms, structure and functions of alkaline phosphatase with special focus on liver/bone/kidney alkaline phosphatase.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

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

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

    African Journals Online (AJOL)

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

  1. Propylene polymerization in a circulating slugging fluidized bed reactor

    NARCIS (Netherlands)

    van Putten, I.C.

    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.

  2. Heat exchanger support apparatus in a fluidized bed

    Science.gov (United States)

    Lawton, Carl W.

    1982-01-01

    A heat exchanger is mounted in the upper portion of a fluidized combusting bed for the control of the temperature of the bed. A support, made up of tubes, is extended from the perforated plate of the fluidized bed up to the heat exchanger. The tubular support framework for the heat exchanger has liquid circulated therethrough to prevent deterioration of the support.

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

    Directory of Open Access Journals (Sweden)

    A. Shukrie

    2016-06-01

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

  4. Advanced alkaline water electrolysis

    International Nuclear Information System (INIS)

    Marini, Stefania; Salvi, Paolo; Nelli, Paolo; Pesenti, Rachele; Villa, Marco; Berrettoni, Mario; Zangari, Giovanni; Kiros, Yohannes

    2012-01-01

    A short review on the fundamental and technological issues relevant to water electrolysis in alkaline and proton exchange membrane (PEM) devices is given. Due to price and limited availability of the platinum group metal (PGM) catalysts they currently employ, PEM electrolyzers have scant possibilities of being employed in large-scale hydrogen production. The importance and recent advancements in the development of catalysts without PGMs are poised to benefit more the field of alkaline electrolysis rather than that of PEM devices. This paper presents our original data which demonstrate that an advanced alkaline electrolyzer with performances rivaling those of PEM electrolyzers can be made without PGM and with catalysts of high stability and durability. Studies on the advantages/limitations of electrolyzers with different architectures do show how a judicious application of pressure differentials in a recirculating electrolyte scheme helps reduce mass transport limitations, increasing efficiency and power density.

  5. Hydrodynamic studies in designing of fluidized bed system

    International Nuclear Information System (INIS)

    Mohamad Puad Abu; Muhd Noor Muhd Yunus; Syed Nasaruddin Syed Idris

    2002-01-01

    Fluidized bed process have been used mostly in the petroleum and paper industries, and for processing nuclear wastes, spent cook liquor, wood chips, and sewage sludge disposal. Even at MINT some of the equipment available used this principal. Before we use or purchase this equipment, it is very grateful if we could understand how the system has been designed. The hydrodynamic fluidization studies is very important in designing of fluidized bed system especially in determining the minimum fluidizing velocity, terminal velocity, flexibility of operation, slugging condition, bubble size and velocity, and transport disengaging height. They can be determined either by calculation or experimentation. This paper will highlight the hydrodynamic study that need to be performed in designing of fluidized bed system so that its can be used appropriately. (Author)

  6. Synthetic sorbents for removal of sulfur dioxide in fluidized-bed coal combustors. [25 refs

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, R.B.; Wilson, W.I.; Johnson, I.; Jonke, A.A.

    1977-06-01

    Synthetic sorbents have been investigated for use in place of limestone for SO/sub 2/ emission control in fluidized-bed coal combustors. Sorbents prepared by impregnation of porous alumina with alkali metal or alkaline earth oxides were studied. The most promising sorbent was found to be calcium oxide in alumina. However, the SO/sub 2/ reactivity of this synthetic sorbent was less than that for a moderately reactive limestone. Hence, a greater quantity of synthetic sorbent would be needed to meet SO/sub 2/ emission standards. The attrition resistance of this synthetic sorbent was found to be greater than that of natural stones; therefore, a larger number of cycles of use would be expected. It is estimated that the use of this synthetic sorbent would reduce the amount of waste sorbent to about one-sixth the amount expected using a moderately reactive once-through limestone. The cost of using this synthetic sorbent is estimated to be about three and a half times the cost expected using once-through limestone. This cost is considered to be too large in view of the expected modest decrease in environmental impact. The synthetic sorbents developed in this study are therefore not considered viable alternatives for limestone in fluidized-bed coal combustors.

  7. [Advances of alkaline amylase production and applications].

    Science.gov (United States)

    Yang, Haiquan; Liu, Long; Li, Jianghua; Du, Guocheng; Chen, Jian

    2012-04-01

    Alkaline amylase is one of alkaline enzymes with optimum pH in the alkaline range, and it could keep stability and efficiently hydrolyze starch under alkaline conditions. Alkaline amylase finds wide applications in textile, detergent, pharmaceutical, food and other fields. Alkaline amylases could be produced by alkaliphilic microorganisms. In this work, the advances of alkaline amylase production and applications were reviewed.

  8. Viscosity of Molten Alkaline-Earth Fluorides

    Science.gov (United States)

    Takeda, Osamu; Hoshino, Yosuke; Anbo, Yusuke; Yanagase, Kei-ichi; Aono, Masahiro; Sato, Yuzuru

    2015-04-01

    The viscosities of molten alkaline-earth fluorides were measured using the oscillating crucible method, which is especially suitable for measuring molten salts with low viscosity. The results showed a good Arrhenius linearity over a wide temperature range. The measured viscosities and activation energies increased in the following order: . Judging by the charge density, the viscosity of alkaline-earth fluorides should increase from molten to . However, the results indicate a different tendency, which may be explained by a Coulomb force that is very strong. The low viscosity of can be attributed to a decreased cohesive force, due to a partial loss of the Coulomb force caused by a higher charge density of the material. The viscosities were also compared to those of molten alkali fluorides and alkaline-earth chlorides. The viscosities of molten alkaline-earth fluorides were higher than those of molten alkali fluorides and alkaline-earth chlorides. The viscosity determined in this study was compared to literature values and showed a reasonable value in the relatively low-viscosity region.

  9. Archimedes' principle in fluidized granular systems.

    Science.gov (United States)

    Huerta, D A; Sosa, Victor; Vargas, M C; Ruiz-Suárez, J C

    2005-09-01

    We fluidize a granular bed in a rectangular container by injecting energy through the lateral walls with high-frequency sinusoidal horizontal vibrations. In this way, the bed is brought to a steady state with no convection. We measured buoyancy forces on light spheres immersed in the bed and found that they obey Archimedes' principle. The buoyancy forces decrease when we reduce the injected energy. By measuring ascension velocities as a function of gamma, we can evaluate the frictional drag of the bed; its exponential dependence agrees very well with previous findings. Rising times of the intruders ascending through the bed were also measured, they increase monotonically as we increase the density.

  10. Fluidized bed adsorption of cephalosporin C.

    Science.gov (United States)

    Hicketier, M; Buchholz, K

    2002-02-28

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

  11. 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.

  12. Electrostatic collection efficiency in binary fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

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

  13. Pyrolysis reactor and fluidized bed combustion chamber

    Science.gov (United States)

    Green, Norman W.

    1981-01-06

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

  14. 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.)

  15. Next generation fluidized bed granulator automation.

    Science.gov (United States)

    Rantanen, J; Känsäkoski, M; Suhonen, J; Tenhunen, J; Lehtonen, S; Rajalahti, T; Mannermaa, J P; Yliruusi, J

    2000-05-06

    A system for fluidized bed granulator automation with in-line multichannel near infrared (NIR) moisture measurement and a unique air flow rate measurement design was assembled, and the information gained was investigated. The multivariate process data collected was analyzed using principal component analysis (PCA). The test materials (theophylline and microcrystalline cellulose) were granulated and the calibration behavior of the multichannel NIR set-up was evaluated against full Fourier Transform (FT) NIR spectra. Accurate and reliable process air flow rate measurement proved critical in controlling the granulation process. The process data describing the state of the process was projected in two dimensions, and the information from various trend charts was outlined simultaneously. The absorbence of test material at correction wavelengths (NIR region) and the nature of material-water interactions affected the detected in-line NIR water signal. This resulted in different calibration models for the test materials. Development of process analytical methods together with new data visualization algorithms creates new tools for in-process control of the fluidized bed granulation.

  16. Fluidized bed gasification of select granular biomaterials.

    Science.gov (United States)

    Subramanian, P; Sampathrajan, A; Venkatachalam, P

    2011-01-01

    Biomaterials can be converted into solid, liquid and gaseous fuels through thermochemical or biochemical conversion processes. Thermochemical conversion of granular biomaterials is difficult because of its physical nature and one of the suitable processes is fluidized bed gasification. In this study, coir pith, rice husk and saw dust were selected and synthetic gas was generated using a fluidized bed gasifier. Gas compositions of product gas were analyzed and the percentage of carbon monoxide and carbon dioxide was in the range of 8.24-19.55 and 10.21-17.14, respectively. The effect of equivalence ratio (0.3, 0.4 and 0.5) and reaction time (at 10 min interval) on gas constituents was studied. The gas yield for coir pith, rice husk and sawdust were found to be in the range of 1.98-3.24, 1.79-2.81 and 2.18-3.70 Nm3 kg(-1), respectively. Models were developed to study the influence of biomaterial properties and operating conditions on molar concentration of gas constituents and energy output. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Rocky Flats Plant fluidized-bed incinerator

    International Nuclear Information System (INIS)

    Meile, L.J.; Meyer, F.G.; Johnson, A.J.; Ziegler, D.L.

    1982-01-01

    Laboratory and pilot-scale testing of a fluidized-bed incineration process for radioactive wastes led to the installation of an 82-kg/hr demonstration unit at Rocky Flats Plant in 1978. Design philosophy and criteria were formulated to fulfill the needs and objectives of an improved radwaste-incineration system. Unique process concepts include low-temperature (550 0 C), flameless, fluidized-bed combustion and catalytic afterburning; in-situ neutralization of acid gases; and dry off-gas cleanup. Detailed descriptions of the process and equipment are presented along with a summary of the equipment and process performance during a 2-1/2 year operational-testing period. Equipment modifications made during the test period are described. Operating personnel requirements for solid-waste burning are shown to be greater than those required for liquid-waste incineration; differences are discussed. Process-utility and raw-materials consumption rates for full-capacity operation are presented and explained. Improvements in equipment and operating procedures are recommended for any future installations. Process flow diagrams, an area floor plan, a process-control-system schematic, and equipment sketches are included

  18. Parameters critical to the morphology of fluidization craters

    Science.gov (United States)

    Siegal, B. S.; Gold, D. P.

    1973-01-01

    In order to study further the role of fluidization on the moon, a laboratory investigation was undertaken on two particulate material size fractions to determine the effect of variables, such as, duration of gas streaming, gas pressure, and 'regolith' thickness on the morphology of fluidization craters. A 3.175-mm cylindrical vent was used to simulate a gas streaming conduit. Details of the fluidization chamber are discussed together with questions of experimental control, aspects of nomenclature, crater measurements, and the effect of variables.

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

    DEFF Research Database (Denmark)

    Narayan, Vikas

    at Risø and a 6 MW LTCFB gasifier owned by DONG ENERGY and placed in Kalundborg. In addition to the analysis of the inorganic elemental composition of the collected samples, SEM and TGA analysis of the samples were made to improve understanding on the behavior of the ash forming species within the system...... the bed particle diameters and the fraction of K entrained from the system. The model was also applied to study the de-fluidization behavior of alkali-rich samples in a large scale LTCFB gasifier. The model was used to predict the variations in de-fluidization time on a full scale LTCFB plant with respect...... ensures that high-alkali biomass fuels can be used without risks of bed de-fluidization. This thesis aims to understand the behavior of alkali metals and ash in the LTCFB system. The thesis work involved measurements made on bed material and product gas dust samples on a 100kW LTCFB gasifier placed...

  20. Dust removal from waste gas arising from fluidized beds

    International Nuclear Information System (INIS)

    Soltys, L.

    1992-01-01

    Two types dust removal equipment mostly useful for dust removal from waste gas from fluidized beds, i.e. electrofilters and pulsatory bag filters were presented. Their features and functional properties were compared. (author). 7 refs, 4 figs

  1. Synchronized oscillations and acoustic fluidization in confined granular materials

    Science.gov (United States)

    Giacco, F.; de Arcangelis, L.; Ciamarra, M. Pica; Lippiello, E.

    2018-01-01

    According to the acoustic fluidization hypothesis, elastic waves at a characteristic frequency form inside seismic faults even in the absence of an external perturbation. These waves are able to generate a normal stress which contrasts the confining pressure and promotes failure. Here, we study the mechanisms responsible for this wave activation via numerical simulations of a granular fault model. We observe the particles belonging to the percolating backbone, which sustains the stress, to perform synchronized oscillations over ellipticlike trajectories in the fault plane. These oscillations occur at the characteristic frequency of acoustic fluidization. As the applied shear stress increases, these oscillations become perpendicular to the fault plane just before the system fails, opposing the confining pressure, consistently with the acoustic fluidization scenario. The same change of orientation can be induced by external perturbations at the acoustic fluidization frequency.

  2. Gasification of rice husk in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mansaray, K.G.

    1998-12-31

    The development of two mathematical models which simulate the performance of a dual distributor fluidized bed gasifier was described. The gasification of rice husks in the gasifier using air as the sole gasifying agent was investigated. The four stages of the study were: (1) modification of the existing fluidized bed gasifier and data acquisition system, (2) preliminary experimentation to assess the suitability of rice husks for gasification to determine the feasible range of operating conditions for fluidized bed gasification of rice husks and to obtain data for proper design of thermochemical conversion systems, (3) development of mathematical models to predict the performance of the fluidized bed gasification system, and (4) experimentation to investigate the effects of various operating variables on the performance of the gasifier and provide data to evaluate the validity of the models.

  3. Synthesis of carbon nanotubes using fluidized bed technology

    CSIR Research Space (South Africa)

    Swartbooi, AM

    2008-11-01

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

  4. 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.

  5. Fluidized Bed Sputtering for Particle and Powder Metallization

    Science.gov (United States)

    2013-04-01

    Sathiyamoorthy provides a review of plasma technology used with fluidized bed techniques (13). Borer and von Rohr integrated a microwave plasma source...Plasma Spouted/Fluidized Bed for Materials Processing. Journal of Physics: Conference Series 2010, 208 (1), 012120. 14. Borer, B.; von Rohr , R...Technology 2005, 200, 377–381. 15. Morstein, M.; Karches, M.; Bayer, C.; Casanova, D.; von Rohr , P. R. Plasma CVD of Ultrathin TiO2 Films on Powders in a

  6. Fluidized-bed calciner with combustion nozzle and shroud

    International Nuclear Information System (INIS)

    Wielang, J.A.; Palmer, W.B.; Kerr, W.B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition. 4 claims, 2 figures

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

    International Nuclear Information System (INIS)

    Sarra, Scott A.

    2003-01-01

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

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

    CERN Document Server

    Sarra, S A

    2003-01-01

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

  9. Pulsed atmospheric fluidized bed combustion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

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

  10. Alkaline Activator Impact on the Geopolymer Binders

    Science.gov (United States)

    Błaszczyński, Tomasz Z.; Król, Maciej R.

    2017-10-01

    Concrete structures are constantly moving in the direction of improving the durability. Durability depends on many factors, which are the composition of concrete mix, the usage of additives and admixtures and the place, where material will work and carry the load. The introduction of new geopolymer binders for geopolymer structures adds a new aspect that is type of used activator. This substance with strongly alkaline reaction is divided because of the physical state, the alkaline degree and above all the chemical composition. Taking into account, that at present the geopolymer binders are made essentially from waste materials or by-products from the combustion of coal or iron ore smelting, unambiguous determination of the effect of the activator on the properties of the geopolymer material requires a number of trials, researches and observation. This paper shows the influence of the most alkaline activators on the basic parameters of the durability of geopolymer binders. In this study there were used highly alkaline hydroxides, water glasses and granules, which are waste materials in a variety of processes taking place in chemical plants. As the substrate of geopolymer binders there were used fly ash which came from coal and high calcareous ash from the burning of lignite.

  11. Alkaline fuel cells applications

    Science.gov (United States)

    Kordesch, Karl; Hacker, Viktor; Gsellmann, Josef; Cifrain, Martin; Faleschini, Gottfried; Enzinger, Peter; Fankhauser, Robert; Ortner, Markus; Muhr, Michael; Aronson, Robert R.

    On the world-wide automobile market technical developments are increasingly determined by the dramatic restriction on emissions as well as the regimentation of fuel consumption by legislation. Therefore there is an increasing chance of a completely new technology breakthrough if it offers new opportunities, meeting the requirements of resource preservation and emission restrictions. Fuel cell technology offers the possibility to excel in today's motive power techniques in terms of environmental compatibility, consumer's profit, costs of maintenance and efficiency. The key question is economy. This will be decided by the costs of fuel cell systems if they are to be used as power generators for future electric vehicles. The alkaline hydrogen-air fuel cell system with circulating KOH electrolyte and low-cost catalysed carbon electrodes could be a promising alternative. Based on the experiences of Kordesch [K. Kordesch, Brennstoffbatterien, Springer, Wien, 1984, ISBN 3-387-81819-7; K. Kordesch, City car with H 2-air fuel cell and lead-battery, SAE Paper No. 719015, 6th IECEC, 1971], who operated a city car hybrid vehicle on public roads for 3 years in the early 1970s, improved air electrodes plus new variations of the bipolar stack assembly developed in Graz are investigated. Primary fuel choice will be a major issue until such time as cost-effective, on-board hydrogen storage is developed. Ammonia is an interesting option. The whole system, ammonia dissociator plus alkaline fuel cell (AFC), is characterised by a simple design and high efficiency.

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

    Energy Technology Data Exchange (ETDEWEB)

    Korcak, R.F.

    1980-01-01

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

  13. Fluidized bed material apples at disposal levels: effects on an apple orchard. [Malus domestica Borkh

    Energy Technology Data Exchange (ETDEWEB)

    Korcak, R.F.

    Atmospheric fluidized-bed combustion represents and economical technology for the burning of high S fossil fuel. The combustion residue is a dry, alkaline material resulting from the burning of coal (or other fuel source) and limestone. Although the residue has been assessed as a limestone substitute, the current study examines the potential for disposing of relatively large quantities. Fluidized bed material (FBM) was applied at two rates to the surface area within the rows of an established apple (Malus domestica Borkh.) orchard containing four tree types. The rates were either 9.2 kg/m/sup 2/ (low rate), 36 kg/m/sup 2/ (high rate), or untreated control. The tree types used were Spuree Rome on M9, Redchief Delicious on M9 or M9/MM106, and Sturdeespur Delicious on M9. Cumulative yields (kg/tree) were enhanced on three of four tree types over a period of 6 yr. A 15% reduction in yield was noted for Redchief Delicious on M9/MM106 stocks at the high FBM rate. No nutritional related problems were noted for this or any other of the tree types used. Part of the yield reduction noted was due to fruit size differences and/or differential sensitivity of this interstock/rootstock combination to the altered soil chemical properties. Generally, amended soil pH increased to about 7.0 for either rate, and electrical conductivity increased five fold at the high rate of FBM addition. Agricultural utilization of large volume (up to 112 Mg/ha) of FBM, compared to past research where FBM was used as a lime substitute (2-6 mg/ha), appears to be a feasible alternative. However, rootstock selection for apple may need to consider the resultant changes in soil chemical status from FBM additions.

  14. Method of cleaning alkaline metal

    International Nuclear Information System (INIS)

    Kawakami, Yukio; Naito, Kesahiro; Iizawa, Katsuyuki; Nakasuji, Takashi

    1981-01-01

    Purpose: To prevent scattering of used sodium and aqueous alkaline solution when cleaning used sodium and metallic sodium adhering to equipment with an aqueous alkaline solution. Method: A sodium treating container is filled with an aqueous alkaline solution, and stainless steel gauze is sunk in the container. Equipment to be cleaned such as equipment with sodium adhering to it are retained under the gauze and are thus cleaned. On the other hand, the surface of the aqueous alkaline solution is covered with a fluid paraffin liquid covering material. Thus, the hydrogen produced by the reaction of the sodium and the aqueous alkaline solution will float up, pass through the liquid covering material and be discharged. The sodium will pass through the gauze and float upwardly while reacting with the aqueous alkaline solution in a partic ulate state to the boundary between the aqueous alkaline solution and up to the covering material, and thus the theratment reaction will continue. Thus, the cover material prevents the sodium and the aqueous alkaline solution from scattering. (Kamimura, M.)

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

    NARCIS (Netherlands)

    Kersten, Sascha R.A.; Prins, W.; van der Drift, Bram; van Swaaij, Willibrordus Petrus Maria

    2003-01-01

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

  16. An experimental study of the effect of collision properties on spout fluidized bed dynamics

    NARCIS (Netherlands)

    van Buijtenen, M.S.; Börner, Matthias; Deen, N.G.; Heinrich, Stefan; Antonyuk, Sergiy; Kuipers, J.A.M.

    2009-01-01

    In this paper we experimentally study the effect of collision properties of different particle systems on the bed dynamics of a spout fluidized bed. This is done in different flow regimes: the spout-fluidization regime (case A), the jet-in-fluidized-bed regime (case B) and the spouting-with-aeration

  17. 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 determin...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-10-24

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

  19. Process analysis of fluidized bed granulation.

    Science.gov (United States)

    Rantanen, J; Jørgensen, A; Räsänen, E; Luukkonen, P; Airaksinen, S; Raiman, J; Hänninen, K; Antikainen, O; Yliruusi, J

    2001-10-17

    This study assesses the fluidized bed granulation process for the optimization of a model formulation using in-line near-infrared (NIR) spectroscopy for moisture determination. The granulation process was analyzed using an automated granulator and optimization of the verapamil hydrochloride formulation was performed using a mixture design. The NIR setup with a fixed wavelength detector was applied for moisture measurement. Information from other process measurements, temperature difference between process inlet air and granules (T(diff)), and water content of process air (AH), was also analyzed. The application of in-line NIR provided information related to the amount of water throughout the whole granulation process. This information combined with trend charts of T(diff) and AH enabled the analysis of the different process phases. By this means, we can obtain in-line documentation from all the steps of the processing. The choice of the excipient affected the nature of the solid-water interactions; this resulted in varying process times. NIR moisture measurement combined with temperature and humidity measurements provides a tool for the control of water during fluid bed granulation.

  20. COMPUTATIONAL MODELING OF CIRCULATING FLUIDIZED BED REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Essam A

    2013-01-09

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

  1. Fluidized bed combustion and gasification of corncobs

    Energy Technology Data Exchange (ETDEWEB)

    Butuk, N.; Morey, R.V.

    1987-01-01

    A 15.2 cm (6 in) diameter fluidized bed reactor was evaluated in combustion and gasification modes using hammer milled corncobs with average particle size of 0.2 cm (0.08 in). Combustion tests were run at 10 and 32% w.b. moisture contents and 710 degrees C and 815 degrees C bed temperatures. Heat output rates of 13.4 to 16.2 MJ/h were achieved. Gasification tests were run at 10 and 22% w.b. moisture contents and 710 degrees C bed temperature, and heat output rates of 84 to 133 MJ/h were achieved. Particulates in the exhaust gases were determined in both the combustion and gasification modes of operation. The measurements showed the inadequacy of the flame holder for flaring the gas in the gasification mode. A combustion model based on elemental balances and the first law of thermodynamics was developed and compared to experimental results. The model adequately predicted fuel-air ratios and exhaust gas mass fractions in the combustion mode.

  2. Radioisotope applications on fluidized catalytic cracking units

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1997-01-01

    Radioisotopes are used to trace the flow of all the phases of Fluidized Catalytic Cracking process in oil refineries. The gaseous phases, steam, hydrocarbon vapour and air, are generally traced using a noble-gas isotope, 41 Ar, 79 Kr or 85 Kr. An appropriate tracer for the catalyst is produced by irradiating a catalyst sample in a nuclear reactor. The activation products, 140 La and 24 Na provide appropriate radioactive 'labels' for the catalyst, which is reinjected into the FCC. An advantage of this approach is that it facilitates the study of the behaviour of different particle size fractions. Radioisotopes as sealed sources of gamma radiation are used to measure catalyst density variations and density distributions in critical parts of the unit. An important trend in radioisotope applications is the increasing use of the information they produce as inputs to or as validation of, mathematical process models. In line with the increasing sophistication of the models, the technology is undergoing continuous refinement. Developments include the investigation of more efficient, more convenient tracers, the introduction of systems to facilitate more rapid and comprehensive data acquisition and software refinements for enhanced data analysis

  3. Alkaline direct alcohol fuel cells

    Science.gov (United States)

    Antolini, E.; Gonzalez, E. R.

    The faster kinetics of the alcohol oxidation and oxygen reduction reactions in alkaline direct alcohol fuel cells (ADAFCs), opening up the possibility of using less expensive metal catalysts, as silver, nickel and palladium, makes the alkaline direct alcohol fuel cell a potentially low cost technology compared to acid direct alcohol fuel cell technology, which employs platinum catalysts. A boost in the research regarding alkaline fuel cells, fuelled with hydrogen or alcohols, was due to the development of alkaline anion-exchange membranes, which allows the overcoming of the problem of the progressive carbonation of the alkaline electrolyte. This paper presents an overview of catalysts and membranes for ADAFCs, and of testing of ADAFCs, fuelled with methanol, ethanol and ethylene glycol, formed by these materials.

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

    Science.gov (United States)

    Hu, Xinhui; Cunningham, John; Winstead, Denita

    2008-04-01

    Bed humidity is a critical parameter that needs to be controlled in a fluidized bed granulation to ensure reliability. To predict and control the bed humidity during the fluidized bed granulation process, a simple model based on the mass conservation of moisture was developed. The moisture mass balance model quantitatively simulates the effects of spray rate, binder solution concentration, airflow rate, inlet air temperature, and dew point on the bed humidity. The model was validated by a series of granulations performed in different scale granulators including Glatt GPCG-1, GPCG-15, and GPCG-60. Good agreement was observed between the theoretical prediction and the measured loss on drying (LOD). The model developed in the current work enables us to choose the appropriate parameters for the fluidized bed granulation and can be used as a valuable tool in process scaling-up. 2007 Wiley-Liss, Inc

  5. Experimental study of fluidized bed agglomeration of acerola powder

    Directory of Open Access Journals (Sweden)

    G. C. Dacanal

    2008-03-01

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

  6. Thermal denitrification of evaporators concentrates in reactor with fluidized bed

    International Nuclear Information System (INIS)

    Brugnot, C.

    1993-11-01

    As part of the treatments of liquid wastes coming from the Marcoule reprocessing plant, the study of a thermal denitrification process for evaporator concentrates has been chosen by the CEA/CEN Cadarache: the fluidized-bed calcination. This work presents the study of a calcination pilot-plant for wastes with a very high sodium nitrate content. After a reactional analysis carried out in a thermobalance on samples which are representative of the fluidized-bed compounds, the perfecting of many of the plant parameters - such as the solution injection system - was carried out on a scale-model at first. Then, it was verified on the pilot-plant, and some experiments have been carried out. A mathematical model for the particle growth inside the fluidized-bed is proposed. (author). 179 refs., 65 figs., 23 tabs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-01

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

  8. Iron crystallization in a fluidized-bed Fenton process.

    Science.gov (United States)

    Boonrattanakij, Nonglak; Lu, Ming-Chun; Anotai, Jin

    2011-05-01

    The mechanisms of iron precipitation and crystallization in a fluidized-bed reactor were investigated. Within the typical Fenton's reagent dosage and pH range, ferric ions as a product from ferrous ion oxidation would be supersaturated and would subsequently precipitate out in the form of ferric hydroxide after the initiation of the Fenton reaction. These precipitates would simultaneously crystallize onto solid particles in a fluidized-bed Fenton reactor if the precipitation proceeded toward heterogeneous nucleation. The heterogeneous crystallization rate was controlled by the fluidized material type and the aging/ripening period of the crystallites. Iron crystallization onto the construction sand was faster than onto SiO(2), although the iron removal efficiencies at 180 min, which was principally controlled by iron hydroxide solubility, were comparable. To achieve a high iron removal rate, fluidized materials have to be present at the beginning of the Fenton reaction. Organic intermediates that can form ferro-complexes, particularly volatile fatty acids, can significantly increase ferric ion solubility, hence reducing the crystallization performance. Therefore, the fluidized-bed Fenton process will achieve exceptional performance with respect to both organic pollutant removal and iron removal if it is operated with the goal of complete mineralization. Crystallized iron on the fluidized media could slightly retard the successive crystallization rate; thus, it is necessary to continuously replace a portion of the iron-coated bed with fresh media to maintain iron removal performance. The iron-coated construction sand also had a catalytic property, though was less than those of commercial goethite. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Alkaline Material Effects on Roots of Teeth

    Directory of Open Access Journals (Sweden)

    Sowmya Shetty

    2017-12-01

    Full Text Available The aim of this review was to identify and analyse all studies related to the effects of alkaline materials used in dentistry on roots of teeth. The first part of the review focused on mechanical property alterations of root dentine due to sodium hypochlorite (SH used as an irrigant solution based on MeSH (Medical Subject Heading terms from a previous study by Pascon et al in 2009. The second part reviewed literature on calcium hydroxide (CH, mineral trioxide aggregate (MTA and other alkaline materials used as root canal dressings or filling materials. Additional MeSH terms used included “compressive strength”, “elastic modulus” “flexural strength”, “fracture strength” and “fracture resistance”. The language filter was English. Of the initial 205 articles identified, 49 were included in this review, of which 29 were on SH, 21 on CH/MTA, and 1 relating to both. Many in vitro studies indicated a strong link between reduced mechanical properties of roots of teeth or radicular dentine treated with SH, and when sealers or root fillings with CH- or MTA-based materials were placed in contact with roots or radicular dentine. Recent literature indicates that the association between reduced mechanical properties and alkaline sealers and/or root-filling materials is not as straightforward as previously assumed, and requires further investigation using more valid experimental models.

  10. Volatiles combustion in fluidized beds. Technical progress report, 4 March 1993--3 June 1993

    Energy Technology Data Exchange (ETDEWEB)

    Hesketh, R.P.

    1993-09-01

    The goal of this project is to investigate the conditions in which volatiles will burn within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization will be performed to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. The work conducted during the period 4 March, 1993 through 3 June, 1993 is reported in this technical progress report. The work during this time period consists primarily of the startup and trouble shooting of the fluidized bed reactor and gas phase modeling of methane and propane.

  11. 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.

  12. Pressurized fluidized-bed combustion technology exchange workshop

    Energy Technology Data Exchange (ETDEWEB)

    ,

    1980-04-01

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

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

    CERN Document Server

    Valk, M

    1994-01-01

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

  14. Transformations of calcium sulphates in solidified carbonated volatile fluidized ashes

    Directory of Open Access Journals (Sweden)

    Marian Jacek Łączny

    2017-01-01

    During the investigation it was assumed that calcium carbonate, being poorly water-soluble, would not react with the remaining components of the porous water of the volatile fluidized ash. Crystalline phases of calcium sulphates, anhydrite, gypsum and bassanite occurring in bound volatile fluidized ashes after carbonation demonstrate the possibility of crystallization in the presence of calcium carbonate. In particular, a change in the concentration of bassanite indicates that this phase, as a precursor to the crystallization of gypsum, may play a significant role in the process of binding carbonated volatile ashes.

  15. Boundary conditions for soft glassy flows: slippage and surface fluidization.

    Science.gov (United States)

    Mansard, Vincent; Bocquet, Lydéric; Colin, Annie

    2014-09-28

    We explore the question of surface boundary conditions for the flow of a dense emulsion. We make use of microlithographic tools to create surfaces with well controlled roughness patterns and measure using dynamic confocal microscopy both the slip velocity and the shear rate close to the wall, which we relate to the notion of surface fluidization. Both slippage and wall fluidization depend non-monotonously on the roughness. We interpret this behavior within a simple model in terms of the building of a stratified layer and the activation of plastic events by the surface roughness.

  16. 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.

  17. Multiphase Flow and Fluidization Continuum and Kinetic Theory Descriptions

    CERN Document Server

    Gidaspow, Dimitri

    1994-01-01

    Useful as a reference for engineers in industry and as an advanced level text for graduate engineering students, Multiphase Flow and Fluidization takes the reader beyond the theoretical to demonstrate how multiphase flow equations can be used to provide applied, practical, predictive solutions to industrial fluidization problems. Written to help advance progress in the emerging science of multiphase flow, this book begins with the development of the conservation laws and moves on through kinetic theory, clarifying many physical concepts (such as particulate viscosity and solids pressure) and i

  18. FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2006-12-22

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

  19. On the entrainment of solid particles from a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Sciazko, M. (Institute of Chemical Processing of Coal, Zabrze (Poland)); Bandrowski, J.; Raczek, J. (Politechnika Slaska, Gliwice (Poland). Inst. of Chemical Engineering and Apparatus Construction)

    1991-04-01

    This paper presents a generalized approach to the phenomenon of entrainment of solids from a fluidized bed. Starting with the discussion of the transport disengaging height (TDH) and of the elutriation of particles above the TDH, one arrives finally at the relationship between the elutriation rate constant, saturation carrying capacity and choking parameters of pneumatic transport. (orig.).

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

    Science.gov (United States)

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

    1991-08-20

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

  1. 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.)

  2. substrate reduction kinetics and performance evaluation of fluidized

    African Journals Online (AJOL)

    eobe

    UASB reactor system before the treatment begins [6]. Open pit (aerobic) treatment system which is currently being employed at the brewery is characterized by high sludge generation with its attendant disposal problems. Slaughterhouse wastewater [7] and corn starch wastewater [8] have been treated using Fluidized-bed ...

  3. In silico modeling of in situ fluidized bed melt granulation.

    Science.gov (United States)

    Aleksić, Ivana; Duriš, Jelena; Ilić, Ilija; Ibrić, Svetlana; Parojčić, Jelena; Srčič, Stanko

    2014-05-15

    Fluidized bed melt granulation has recently been recognized as a promising technique with numerous advantages over conventional granulation techniques. The aim of this study was to evaluate the possibility of using response surface methodology and artificial neural networks for optimizing in situ fluidized bed melt granulation and to compare them with regard to modeling ability and predictability. The experiments were organized in line with the Box-Behnken design. The influence of binder content, binder particle size, and granulation time on granule properties was evaluated. In addition to the response surface analysis, a multilayer perceptron neural network was applied for data modeling. It was found that in situ fluidized bed melt granulation can be used for production of spherical granules with good flowability. Binder particle size had the most pronounced influence on granule size and shape, suggesting the importance of this parameter in achieving desired granule properties. It was found that binder content can be a critical factor for the width of granule size distribution and yield when immersion and layering is the dominant agglomeration mechanism. The results obtained indicate that both in silico techniques can be useful tools in defining the design space and optimization of in situ fluidized bed melt granulation. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    NARCIS (Netherlands)

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

    2005-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-08-01

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

  6. Minimum slugging velocity in fluidized beds containing vertical rods

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-09-01

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

  7. The porosity in a fluidized bed heat transfer model

    NARCIS (Netherlands)

    Visser, G; Visser, G.; Valk, M.

    1993-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Egorov Ivan

    2017-01-01

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

  9. Physical Characteristics of Fluidized Beds via Pressure Fluctuation Analysis

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Trnka, Otakar

    2008-01-01

    Roč. 54, č. 7 (2008), s. 1761-1769 ISSN 0001-1541 R&D Projects: GA AV ČR IAA400720701 Institutional research plan: CEZ:AV0Z40720504 Keywords : gas-solid fluidization * pressure fluctuations * fluctuation characteristics Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.883, year: 2008

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

    African Journals Online (AJOL)

    ... out in an inverse fluidized bed bioreactor using low density (870 kg/m3) polypropylene particles. Experiments were carried at different initial substrate concentration of 2250, 4475, 6730 and 8910mg COD/L and for various hydraulic retention time 40, 32, 24, 16 and 8h. Degradation of organic matter was studied at different ...

  11. Low temperature fluidized wood chip drying with monoterpene analysis

    Science.gov (United States)

    Bridget N. Bero; Alarick Reiboldt; Ward Davis; Natalie Bedard; Evan Russell

    2011-01-01

    This paper describes the drying of ponderosa pine wood chips at low (20°C and 50°C) temperatures using a bench-scale batch pulsed fluidizer to evaluate both volatile pine oils (monoterpenes) and moisture losses during drying.

  12. substrate reduction kinetics and performance evaluation of fluidized ...

    African Journals Online (AJOL)

    pilot scale anaerobic fluidized-bed reactor was operated for treating brewery wastewater at nine different hydraulic retention time (HRTs) of 2, 3, 4, 5, 6, 7, 8, 9, and 10hr. The COD reduction efficiencies increased from 9.8% to 74.1% with increasing HRT from 2 to 10hr.Similarly, the corresponding BOD5 reduction efficiencies ...

  13. 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.

  14. Electrochemical Ion-Exchange Regeneration and Fluidized Bed Crystallization for Zero-Liquid-Discharge Water Softening.

    Science.gov (United States)

    Chen, Yingying; Davis, Jake R; Nguyen, Chi H; Baygents, James C; Farrell, James

    2016-06-07

    This research investigated the use of an electrochemical system for regenerating ion-exchange media and for promoting the crystallization of hardness minerals in a fluidized bed crystallization reactor (FBCR). The closed-loop process eliminates the creation of waste brine solutions that are normally produced when regenerating ion-exchange media. A bipolar membrane electrodialysis stack was used to generate acids and bases from 100 mM salt solutions. The acid was used to regenerate weak acid cation (WAC) ion-exchange media used for water softening. The base solutions were used to absorb CO2 gas and to provide a source of alkalinity for removing noncarbonate hardness by WAC media operated in H(+) form. The base solutions were also used to promote the crystallization of CaCO3 and Mg(OH)2 in a FBCR. The overall process removes hardness ions from the water being softened and replaces them with H(+) ions, slightly decreasing the pH value of the softened water. The current utilization efficiency for acid and base production was ∼75% over the operational range of interest, and the energy costs for producing acids and bases were an order of magnitude lower than the costs for purchasing acid and base in bulk quantities. Ion balances indicate that the closed-loop system will accumulate SO4(2-), Cl(-), and alkali metal ions. Acid and base balances indicate that for a typical water, small amounts of base will be accumulated.

  15. Dissolved oxygen control in a coupled fluidized bed system

    International Nuclear Information System (INIS)

    Jones, R.M.; Melcer, H.

    1988-01-01

    The biological fluidized bed process is a modification of more conventional fixed film processes, such as the trickling filter, in which wastewater is passed upward through a bed of granular support medium, typically sand, at a sufficient velocity to expand or fluidize the medium. The granular medium provides a large surface area for the establishment of a biological film. The fluidized bed process was selected to investigate the treatment of coking plant wastewaters in view of the significant advantages offered in terms of reduced reactor volumes that result from the high biomass concentration maintained on the support medium. The technical feasibility of treating coal distillation condensates was evaluated during a 3-year study at Environment Canada's Wastewater Technology Centre (WTC). The feed to the pilot scale test system consisted of effluent from fixed and free leg ammonia stills at the by-product coke plant of Dofasco Inc. in Hamilton, Ontario. The pilot plant consisted of two fluidized bed reactors in series, coupled to provide carbon oxidation, nitrification and denitrification in the predenitrification operating mode. The anoxic denitrification reactor was 115 mm in diameter and the oxygenic nitrification reactor, 290 mm in diameter. The bed heights and reactor volumes were adjustable by relocation of the position of the sand/biomass wasting valve. The experimental objective of this research was to determine those operating conditions required to maintain stable nitrification and complete denitrification under both steady state and dynamic operating conditions. Details regarding operating, sampling and analytic procedures have been presented elsewhere. A specific operating problem existed relating to the control of the dissolved oxygen concentration in the oxygenic fluidized bed reactor, the solution of which forms the basis of the paper

  16. Sodic alkaline stress mitigation by exogenous melatonin in tomato needs nitric oxide as a downstream signal.

    Science.gov (United States)

    Liu, Na; Gong, Biao; Jin, Zhiyong; Wang, Xiufeng; Wei, Min; Yang, Fengjuan; Li, Yan; Shi, Qinghua

    2015-08-15

    The present study was designed to determine the interactive effect of exogenous melatonin and nitric oxide (NO) on sodic alkaline stress mitigation in tomato seedlings. It was observed that exogenous melatonin treatment elevated NO levels in alkaline-stressed tomato roots. However, exogenous NO had little effects on melatonin levels. Importantly, melatonin-induced NO generation was accompanied by increased tolerance to alkaline stress. Chemical scavenging of NO reduced melatonin-induced alkaline stress tolerance and defense genes' expression. However, inhibition of melatonin biosynthesis had a little effect on NO-induced alkaline stress tolerance. These results strongly suggest that NO, acting as a downstream signal, is involved in the melatonin-induced tomato tolerance to alkaline stress. This process creates a new signaling pathway for improving stress tolerance in plant. Copyright © 2015 Elsevier GmbH. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  19. Sodium and steam leak simulation studies for fluidized bed steam generators

    International Nuclear Information System (INIS)

    Keeton, A.R.; Vaux, W.G.; Lee, P.K.; Witkowski, R.E.

    1976-01-01

    An experimental program is described which was conducted to study the effects of sodium or steam leaking into an operating fluidized bed of metal or ceramic particles at 680 to 800 0 K. This effort was part of the early development studies for a fluidized-bed steam generator concept using helium as the fluidizing gas. Test results indicated that steam and small sodium leaks had no effect on the quality of fluidization, heat transfer coefficient, temperature distribution, or fluidizing gas pressure drop across the bed. Large sodium leaks, however, immediately upset the operation of the fluidized bed. Both steam and sodium leaks were detected positively and rapidly at an early stage of a leak by instruments specifically selected to accomplish this

  20. Minimum and Full Fluidization Velocity for Alumina Used in the Aluminum Smelter

    Directory of Open Access Journals (Sweden)

    Paulo Douglas S. de Vasconcelos

    2011-11-01

    Full Text Available Fluidization is an engineering unit operation that occurs when a fluid (liquid or gas ascends through a bed of particles, and these particles get a velocity of minimum fluidization enough to stay in suspension, but without carrying them in the ascending flow. As from this moment the powder behaves as liquid at boiling point, hence the term “fluidization”. This operation is widely used in the aluminum smelter processes, for gas dry scrubbing (mass transfer and in a modern plant for continuous alumina pot feeding (particles’ momentum transfer. The understanding of the alumina fluoride rheology is of vital importance in the design of fluidized beds for gas treatment and fluidized pipelines for pot feeding. This paper shows the results of the experimental and theoretical values of the minimum and full fluidization velocities for the alumina fluoride used to project the state of the art round non‐metallic air‐fluidized conveyor of multiples outlets.

  1. Study of standard tablet formulation based on fluidized-bed granulation.

    Science.gov (United States)

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

    1998-03-01

    In this study, acetaminophen, ascorbic acid, and ethenzamide were selected as model drugs for tableting granules. Agitation and fluidized-bed granulation were carried out at three drug contents of 30, 50, and 70%. Compared with agitation granulation, granules made by fluidized-bed granulation showed superior compressibility with wide formulation allowance for drug type and amount. Fluidized-bed granulation resulted in less granule hardness and greater plastic deformability. The granules had considerable compactness and for tablets containing 70% ethenzamide, prolonged disintegration and dissolution times were noted. These are typical features of granules produced by fluidized-bed granulation.

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

    Science.gov (United States)

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

    2018-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  4. Analysis of the pressure fluctuations in binary solids circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yongguo [School of Mechanical and Power Engineering, Shanghai JiaoTong University, Dongchuan Road 800, Shanghai 200240 (China)]. E-mail: yongguo_chen@hotmail.com; Tian Ziping [School of Mechanical and Power Engineering, Shanghai JiaoTong University, Dongchuan Road 800, Shanghai 200240 (China); Miao Zhengqing [School of Mechanical and Power Engineering, Shanghai JiaoTong University, Dongchuan Road 800, Shanghai 200240 (China)

    2006-03-15

    Pressure fluctuations are often selected to analyze the dynamic changes in the fluidized bed. Many researchers in the field of fluidization have adopted many methods to analyze the pressure signals in fluidized beds, such as statistical analysis (in time domain), frequency analysis (in frequency domain) and non-linear analysis (such as chaotic method). There are many literatures concentrated on statistical analysis in the fluidization field since this method can display the distribution density of the pressure fluctuations. In this study, the pressure fluctuations on the bed wall at different bed heights in the cold two dimensional (2-D) circulating fluidized bed (200 x 30 x 1200 mm{sup 3}) were sampled. The colophony, millet and 20% millet plus 80% colophony were selected as bed materials. The pressure signals were analyzed by means of statistical methods. The correlation equations between the pressure signals and fluidization parameters were obtained under different operational conditions. Finally, comparisons between the single solid and binary solids 2-D circulating fluidized beds were investigated deeply. Two parameters, K {sub 1} (=0.54(u - u {sub mf}){sup 0.4} h {sup 0.8}/g {sup 0.2}) and K {sub 2} (={sigma} {sub b}/({rho} {sub s} g(1 - {epsilon} {sub mf}))), were selected to characterize the fluidization mechanism. It was found that the relationships between K {sub 2} and K {sub 1} among the single solid and binary solids circulating fluidized beds vary a great deal.

  5. Characterization of products from fluidized-bed combustion of coal.

    Science.gov (United States)

    Bednarik, V; Vondruska, M; Sild, M; Vondruskova, E

    2000-11-01

    The technology of fluidized-bed combustion (FBC) of coal generates byproducts that have a series of unique characteristics and potential uses in technological practice. In this study, the products of fluidized-bed combustion (FBC-P) of coal derived from Moravian heat stations, a.s. Zlin, Cinergy Global Resources, Czech Republic, were characterized. Particular attention was paid to determining the chemical composition of FBC-P, the content of polycyclic aromatic hydrocarbons (PAHs) and toxic metals in the water leachates of these FBC-P, the content of unburned carbon, the capability of FBC-P to solidify with water and form a solid matrix, and the method for discovering optimum mixing water content for FBC-P solidification. The results suggest that one of the qualitatively more important means of utilizing FBC-P could be their application during solidification/stabilization (S/S) of wastes, particularly wastewater treatment sludges.

  6. Pulverized coal vs. circulating fluidized bed: An economic comparison

    International Nuclear Information System (INIS)

    Johns, R.F.

    1991-01-01

    As the power industry looks to the 1990s for expanded steam generation capacity, boiler owners will continue on their long-standing assignment to evaluate and select the best, lowest cost alternative to meet their energy needs. For coal-fired plants, this evaluation process includes pulverized coal-fired boilers (PC) and circulating fluidized bed boilers (CFB). The cost difference between these products is site specific and depends on several variables, including: Boiler size, pressure, and temperature; Operating variables, such as the cost for fuel, auxiliary power, SO 2 reagent, and ash disposal; Capital cost; and Financial variables, such as evaluation period and interest rate. This paper provides a technical and economic comparison between a pulverized coal-fired boiler and circulating fluidized bed boiler

  7. Nitrogen Chemistry in Fluidized Bed Combustion of Coal

    DEFF Research Database (Denmark)

    Jensen, Anker Degn

    The present Ph.D thesis describes an experimental and theoretical investigation of the formation and destruction of nitrogen oxides (NOx and N2O) in fluidized bed combustion (FBC) of coal. A review of the current knowledge of nitrogen chemistry in FBC is presented. The review covers both laboratory...... for the emission of NOx from FBC has been developed as part of a JOULE project. The model is based on the two-phase theory of fluidization for the bed with a Kunii-Levenspiel type freeboard model and includes submodels for coal devolatilization, combustion of volatiles and char and a detailed model of NO formation...... and reduction by homogeneous and heterogeneous reactions. The data for the estimation of kinetics of the heterogeneous reactions were measured by one of the partners in the project for char and bed material sampled from a pressurized FBC pilot plant burning Kiveton Park coal. Experimental data from the pilot...

  8. Carbon Shale Combustion in the Fluidized Bed Reactor

    Directory of Open Access Journals (Sweden)

    Olek Małgorzata

    2014-06-01

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

  9. Combustion of Jordanian oil shale using circulating fluidized bed

    International Nuclear Information System (INIS)

    Hamdan, M.; Al-Azzam, S.

    1998-11-01

    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.m 2 and combustion efficiency of 96% were achieved. (authors). 19 refs., 9 tab., 18 fig

  10. A computational fluid dynamic model for fluidized bed heat transfer

    International Nuclear Information System (INIS)

    Yusuf, R.; Melaaen, M.C.; Mathiesen, V.

    2005-01-01

    The objective of this work is to study heat transfer from a heated wall in a gas fluidized bed using the computational fluid dynamic (CFD) approach. An Eulerian-Eulerian simulation of a two dimensional bubbling bed at ambient conditions with a heated wall is carried out on the in-house code FLOTRACS-MP-3D. An empirical as well as a mechanistic model for solid phase thermal conductivity is tested. Effect of operating parameters like velocity and particle size are also investigated. The fluid dynamic model is able to predict the qualitative trends for the influence of operating parameters as well as high heat transfer coefficients observed in gas fluidized beds. (author)

  11. Combustion of refuse derived fuel in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Piao, Guilin; Aono, Shigeru; Mori, Shigekatsu; Deguchi, Seiichi; Fujima, Yukihisa [Nagoya Univ. (Japan); Kondoh, Motohiro; Yamaguchi, Masataka [Toyota Motor Corp. (Japan). Plant Engineering Dept.

    1998-12-31

    Power generation from Refuse Derived Fuel (RDF) is an attractive utilization technology of municipal solid waste. To explain the behavior of RDF-fired fluidized bed incinerator, the commercial size RDF was continuously burnt in a 30 x 30 cm bubbling type fluidized-bed combustor. It was found that 12 kg/h of RDF feed rate was too high feed for this test unit and the Co level was higher than 500 ppm. However, 10 kg/h of RDF was a proper feed rate and the Co level was kept under 150 ppm. Secondary air injection and changing air ratio from the pipe grid were effective for the complete combustion of RDE. It was also found that HCl concentration in flue gas was controlled by the calcium component contained in RDF and its level was decreased with decreasing the combustor temperature.

  12. 2nd Generation Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Yde, Lars; Kjartansdóttir, Cecilia Kristin; Allebrod, Frank

    This report provides the results of the 2nd Generation Alkaline Electrolysis project which was initiated in 2008. The project has been conducted from 2009-2012 by a consortium comprising Århus University Business and Social Science – Centre for Energy Technologies (CET (former HIRC)), Technical...

  13. Zinc electrode in alkaline electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    McBreen, J.

    1995-12-31

    The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. The effect of additives on regular pasted ZnO electrodes and calcium zincate electrodes is discussed. The paper also reports on in situ x-ray absorption (XAS) results on mossy zinc deposits.

  14. Biological reduction of nitrate wastewater using fluidized-bed bioreactors

    International Nuclear Information System (INIS)

    Walker, J.F. Jr.; Hancher, C.W.; Patton, B.D.; Kowalchuk, M.

    1981-01-01

    There are a number of nitrate-containing wastewater sources, as concentrated as 30 wt % NO 3 - and as large as 2000 m 3 /d, in the nuclear fuel cycle as well as in many commercial processes such as fertilizer production, paper manufacturing, and metal finishing. These nitrate-containing wastewater sources can be successfully biologically denitrified to meet discharge standards in the range of 10 to 20 gN(NO 3 - )/m 3 by the use of a fluidized-bed bioreactor. The major strain of denitrification bacteria is Pseudomonas which was derived from garden soil. In the fluidized-bed bioreactor the bacteria are allowed to attach to 0.25 to 0.50-mm-diam coal particles, which are fluidized by the upward flow of influent wastewater. Maintaining the bacteria-to-coal weight ratio at approximately 1:10 results in a bioreactor bacteria loading of greater than 20,000 g/m 3 . A description is given of the results of two biodenitrification R and D pilot plant programs based on the use of fluidized bioreactors capable of operating at nitrate levels up to 7000 g/m 3 and achieving denitrification rates as high as 80 gN(NO 3 - )/d per liter of empty bioreactor volume. The first of these pilot plant programs consisted of two 0.2-m-diam bioreactors, each with a height of 6.3 m and a volume of 208 liters, operating in series. The second pilot plant was used to determine the diameter dependence of the reactors by using a 0.5-m-diam reactor with a height of 6.3 m and a volume of 1200 liters. These pilot plants operated for a period of six months and two months respectively, while using both a synthetic waste and the actual waste from a gaseous diffusion plant operated by Goodyear Atomic Corporation

  15. The grinding of uranium dioxide from fluidized beds

    International Nuclear Information System (INIS)

    Alonso Folgueras, J. A.

    1974-01-01

    This work deals with the UO 2 vibratory grinding, the UO 2 obtained from fluidized beds. In this study the grinding time has been correlated with surface area, stoichiometry, granulometry and grinded product contamination. The efficiency losses in the grinding of moisten UO 2 are outlined. Finally it is made a brief study of the granulate obtained from the grinded UO 2 as well as the green pellets resulting from it, taking into consideration the dispersion of its density and height. (Author)

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

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

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

  17. Fluidized bed reactor for working up carbon coated particles

    International Nuclear Information System (INIS)

    Marschollek, M.; Simon, W.; Walter, C.

    1981-01-01

    A fluidized bed reactor is described for working up carbon coated particles, particularly nuclear fuel particles or fertile material particles consisting essentially of a cylindrical portion connected to a conical portion. Gas supply pipes, gas distribution space and gas distribution heads are provided within the conical reactor lower portion, the gas distribution members being arranged in at least two superimposed planes and distributed symmetrically over the cross-section of the reactor

  18. Gasification of wood in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

  20. Distributor effects near the bottom region of turbulent fluidized beds

    OpenAIRE

    Sobrino Fernández, Celia; Ellis, Noko; Vega Blázquez, Mercedes de

    2009-01-01

    The distributor plate effects on the hydrodynamic characteristics of turbulent fluidized beds are investigated by obtaining measurements of pressure and radial voidage profiles in a column diameter of 0.29 m with Group A particles using bubble bubble-cap or perforated plate distributors. Distributor pressure drop measurements between the two distributors are compared with the theoretical estimations while the influence of the mass inventory is studied. Comparison is established fo...

  1. On the solid stress in a fluidized bed

    International Nuclear Information System (INIS)

    Qassim, R.Y.; Souza, R. de.

    1980-09-01

    The existence of solid stress in an incipiently gas-fluidized bed is shown by experimental measurement. This stress is shown to have two components: an isotropic pressure and an extra stress which depends on the relative velocity between fluid and solid. Both the solid pressure and the solid extra stress component are found to be of the same order of magnitude as the fluid pressure. (Author) [pt

  2. Fluid-dynamic behavior of flaxseed fluidized and spouted bed

    Directory of Open Access Journals (Sweden)

    Elza Brandão Santana

    2017-09-01

    Full Text Available ABSTRACT: Processing of particles in a moving bed, such as a fluidized bed or a spouting bed, is commonly used in the operations of drying, coating, and granulation of particulate systems. This process has applications in the chemical, pharmaceutical and, presently, agronomical industries, especially for seed treatment/coating. This research aimed to analyze the fluid-dynamic behavior of fluidized and spouting beds with different air temperatures and loads of flaxseeds (Linum usitatissimum L., with estimates of the fluid-dynamic parameters correlated to each process. The parameters were compared with the values obtained from classical correlations in the literature, with indications of associated percentages of deviation. Influence of fluid dynamics on the physiological quality of seeds was assessed by germination tests and the germination speed index. An analysis of the results indicated that seed processing was adequate for processing in dynamically active beds; however, temperatures above 50ºC in both beds caused significant reductions in the physiological quality of the seeds. Processing in a fluidized bed presented a smaller reduction of the physiological properties of the flaxseed.

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

    Directory of Open Access Journals (Sweden)

    Saastamoinen Jaakko J.

    2004-01-01

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

  4. Collaborative research on fluidization employing computer-aided particle tracking

    International Nuclear Information System (INIS)

    Chen, M.M.

    1990-01-01

    The objective of this work is to obtain unique, fundamental information on fluidization dynamics over a wide range of flow regimes using a Transportable Computer-Aided Particle Tracking Apparatus (TCAPTA). The contractor will design and fabricate a transportable version of the Computer-Aided Particle Tracking Facility (CAPTF) he has previously developed. The contractor will install and operate the (TCAPTA) at the METC fluidization research facilities. Quantitative data on particle motion will be obtained and reduced. The data will be used to provide needed information for modeling of bed dynamics, and prediction of bed performance, including erosion. A radioactive tracer particle, identical in size shape and mass to the bed particles under study, is mixed in the bed. The radiation emitted by the tracer particle, monitored continuously by 16 scintillation detectors, allows its position to be determined as a function of time. Stochastic mixing processes intrinsic to fluidization further cause the particle to travel to all active regions of the bed, thus sampling the motion in these regions. After a long test run to insure that a sufficient sampling have been acquired, time-differentiation and other statistical processing will then yield the mean velocity distribution, the fluctuating velocity distribution, many types of auto- and cross correlations, as well as mean fluxes, including the mean momentum fluxes due to random motion, which represent the kinetic contributions to the mean stress tensor

  5. 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)

  6. Electrochemical behaviour of alkaline copper complexes

    Indian Academy of Sciences (India)

    cyanide- plating bath for copper has been developed using alkaline trisodium citrate and triethanolamine solutions5. The present investigation presents cyclic voltammetric studies on the electrochemical behaviour of alkaline copper complexes, ...

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

    NARCIS (Netherlands)

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

    1995-01-01

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

  8. Development of alkaline fuel cells.

    Energy Technology Data Exchange (ETDEWEB)

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov

    2013-09-01

    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassovs research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herrings group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

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

    NARCIS (Netherlands)

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

    2008-01-01

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

  11. Investigation of the particle flowpattern and segregation in tapered fluidized bed granulators

    NARCIS (Netherlands)

    Schaafsma, S. H.; Marx, T.; Hoffmann, A. C.

    The particle flowpattern and granule segregation in tapered fluidized beds have been studied using two techniques. The first technique is to fluidize beds of varying total mass and granule fractions, then defluidize them suddenly to "freeze" the composition, section the bed in layers, and determine

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  13. Discrete element modeling and fibre optical measurements for fluidized bed spray granulation

    NARCIS (Netherlands)

    Link, J.M.; Godlieb, W.; Deen, N.G.; Heinrich, S.; Tripp, P.; Peglow, M.; Kuipers, J.A.M.; Schönherr, M.; Mörl, L.

    2007-01-01

    Spout fluidized beds are frequently used for the production of granules or particles through granulation. The products find application in a large variety of applications, for example detergents, fertilizers, pharmaceuticals and food. Spout fluidized beds have a number of advantageous properties,

  14. Characterization of granular phase change materials for thermal energy storage applications in fluidized beds

    International Nuclear Information System (INIS)

    Izquierdo-Barrientos, M.A.; Sobrino, C.; Almendros-Ibáñez, J.A.; Barreneche, C.; Ellis, N.; Cabeza, L.F.

    2016-01-01

    Highlights: • Granular PCMs are tested in 3D and 2D fluidized beds. • Density, particle size and angle of repose were measured for different granular PCMs. • DSC measurements confirm that there is no loss of material after fluidization. - Abstract: This work investigates commercially available granular phase change materials (PCMs) with different transition temperatures for the use of thermal-energy storage systems in fluidized beds. The hydrodynamic characteristics of granular PCMs were tested in cylindrical-3D and planar-2D fluidized beds. The density, particle size distribution and angle of repose were measured for various PCM materials. Further attrition studies were conducted with changes in particle surface from abrasion, which were characterized using a Scanning Electron Microscope (SEM). The results indicate that some materials with smaller particle size and thinner supporting structure can lose the paraffin during the fluidization process, when paraffin is in a liquid state. As a consequence, the particles agglomerate, and the bed defluidizes. For all of the tested materials, only GR50 (with a transition temperature of 50 °C) properly fluidizes when the paraffin is in the liquid state and has shown to endure >75 h of continuous operation and 15 melting-solidification cycles in a fluidized bed. Additional differential scanning calorimetry (DSC) measurements of the cycled particles did not show a decrease in energy storage capacity of the granular PCM, which corroborates that there is no loss of material after >75 h of fluidization.

  15. Mathematical modeling of a fluidized bed rice husk gasifier: Part 2 - Model sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Mansaray, K.G.; Ghaly, A.E.; Al-Taweel, A.M.; Hamdullahpur, F.; Ugursal, V.I.

    2000-02-01

    The performance of two thermodynamic models (one-compartment and two-compartment models), developed for fluidized bed gasification of rice husk, was analyzed and compared in terms of their predictive capabilities of the product gas composition. The two-compartment model was the most adequate to simulate the fluidized bed gasification of rice husk, since the complex hydrodynamics present in the fluidized bed gasifier were taken into account. Therefore, the two-compartment model was tested under a wide range of parameters, including bed height, fluidization velocity, equivalence ratio, oxygen concentration in the fluidizing gas, and rice husk moisture content. The model sensitivity analysis showed that changes in bed height had a significant effect on the reactor temperatures, but only a small effect on the gas composition, higher heating value, and overall carbon conversion. The fluidization velocity, equivalence ratio, oxygen concentration in the fluidizing gas, and moisture content in rice husk had dramatic effects on the gasifier performance. However, the model was more sensitive to variations in the equivalence ratio and oxygen concentration in the fluidizing gas. (Author)

  16. Mathematical modeling of a fluidized bed rice husk gasifier: Part 2 -- Model sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Mansaray, K.G.; Ghaly, A.E.; Al-Taweel, A.M.; Hamdullahpur, F.; Ugursal, V.I.

    2000-03-01

    The performance of two thermodynamic models (one-compartment and two-compartment models), developed for fluidized bed gasification of rice husk, was analyzed and compared in terms of their predictive capabilities of the product gas composition. The two-compartment model was the most adequate to simulate the fluidized bed gasification of rice husk, since the complex hydrodynamics present in the fluidized bed gasifier were taken into account. Therefore, the two-compartment model was tested under a wide range of parameters, including bed height, fluidization velocity, equivalence ratio, oxygen concentration in the fluidizing gas, and rice husk moisture content. The model sensitivity analysis showed that changes in bed height had a significant effect on the reactor temperatures, but only a small effect on the gas composition, higher heating value, and overall carbon conversion. The fluidization velocity, equivalence ratio, oxygen concentration in the fluidizing gas, and moisture content in rice husk had dramatic effects on the gasifier performance. However, the model was more sensitive to variations in the equivalence ratio and oxygen concentration in the fluidizing gas.

  17. Biomass Gasification in Internal Circulating Fluidized Beds: a Thermodynamic Predictive Tool

    Czech Academy of Sciences Publication Activity Database

    Miccio, F.; Svoboda, Karel; Schosger, J.-P.; Baxter, D.

    2008-01-01

    Roč. 25, č. 4 (2008), s. 721-726 ISSN 0256-1115 Institutional research plan: CEZ:AV0Z40720504 Keywords : fluidized bed * gasification * fluidized bed Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.830, year: 2008

  18. Volatiles combustion in fluidized beds. Final technical report, 4 September 1992--4 June 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pendergrass, R.A. II; Raffensperger, C.; Hesketh, R.P.

    1996-02-29

    The goal of this project is to investigate the conditions in which volatiles will burn within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization are being conducted to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. A review of the work conducted under this grant is presented in this Final Technical Report. Both experimental and theoretical work have been conducted to examine the inhibition of the combustion by the fluidized bed material, sand. It has been shown that particulate phase at incipient fluidization inhibits the combustion of propane by free radical destruction at the surface of sand particles within the particulate phase. The implications of these findings is that at bed temperatures lower than the critical temperatures, gas combustion can only occur in the bubble phase or at the top surface of a bubbling fluidized bed. In modeling fluidized bed combustion this inhibition by the particulate phase should be included.

  19. The influence of transport phenomena on the fluidized bed combustion of a single carbon particle

    NARCIS (Netherlands)

    Prins, W.; van Swaaij, Willibrordus Petrus Maria

    1990-01-01

    The burning rate and temperature of the carbon particles are known to affect the efficiency of a fluidized bed combustor, and also the emission levels of undesired noxious components. The main results of an extensive study on the fluidized bed combustion behaviour of a single carbon particle [1] are

  20. The combustion of low calorific value fuels (oil shale) by using fluidized bed combustor

    International Nuclear Information System (INIS)

    Azzam, S.M.

    1993-01-01

    The present work reports an experimental data for combustion of oil-shale in a fluidized bed combustor. The experimental set up was designed for the combustion of low calorific value fuel such as oil-shale to facilitate the variation of many parameters over a wide operating range. A cold run was firstly conducted to study the fluidization parameters. Fluidization experiment were made with different sized quartiz particles. Minimum fluidization velocities and other fluidization characteristics were determined at room temperature. Secondary a hot run was started, first studying the combustion of 'LPG' in a fluidized bed as a starting process, then studying the combustion if oil-shale with different flow rates. The experimetal results are promising and give rise to hopes that this valuable deposit can be used as a fuel source and can be burned sucessfully in a fluidized bed combustor. This study had prooved that utilization of oil-shale a fuel source is no more a complicated technical problem, this opens the way for power generation using fluidized bed combustors. (author). 17 refs., 32 figs., 3 tabs

  1. Combining fluidized activated carbon with weak alternating electric fields for disinfection

    NARCIS (Netherlands)

    Racyte, J.; Sharabati, J.; Paulitsch-Fuchs, A.H.; Yntema, D.R.; Mayer, M.J.J.; Bruning, H.; Rijnaarts, H.H.M.

    2011-01-01

    This study presents fluidized bed electrodes as a new device for disinfection. In the fluidized bed electrodes system, granular activated carbon particles were suspended, and an alternating radio frequency electric field was applied over the suspended bed. Proof-of-principle studies with the

  2. Conversion of ammonium uranyl carbonate to UO2 in a fluidized bed

    International Nuclear Information System (INIS)

    Zhao Jun; Qiu Lufu; Zhong Xing; Xu Heqing

    1989-11-01

    The conversion of AUC (Ammonium Uranyl Carbonate) to UO 2 was studied in a fluidized bed of 60 mm inner diameter based on the thermodynamics and kinetics data of decomposition-reduction of AUC. The influence of the reaction temperature, composition of fluidization gas and fluidization velocity on conversion were investigated by using N 2 , Ar and circulation gas (mixing gas of H 2 and CO obtained from the exhaust gas of the decomposition of AUC by catalyst crack-conversion) as the fluidization gas. The throughput is up to the high levels (3.32 kg(wet)/h·L) by using circulation gas or mixing of circulation gas and Ar (< 21%) as the fluidization gas when the reaction temperature exceeds 570 deg C

  3. Factors affecting the amounts of emissions arising from fluidized bed combustion of solid fuels

    International Nuclear Information System (INIS)

    Horbaj, P.

    1996-01-01

    The factors affecting the amounts of nitrogen oxides (NO x ) and sulfur oxides (SO x , i.e. SO 2 + SO 3 ) formed during fluidized bed combustion of fossil fuels are analyzed using both theoretical concepts and experimental data. The factors treated include temperature, excess air, fuel parameters, pressure, degree of combustion gas recycling, combustion distribution along the combustion chamber height, and sulfur trapping processes for NO x , and the Ca/S ratio, fluidized layer height and fluidization rate, granulometry and absorbent type, fluidized layer temperature, and pressure during combustion for SO x . It is concluded that fluidized bed boilers are promising power generating facilities, mitigating the environmental burden arising from fossil fuel combustion. (P.A.). 12 figs., 9 refs

  4. PENGARUH MASSA JENIS PARTIKEL DAN KETINGGIAN PARTIKEL TERHADAP FENOMENA FLUIDISASI DALAM FLUIDIZED BED DENGAN MENGGUNAKAN CFD

    Directory of Open Access Journals (Sweden)

    Rosyida Permatasari

    2016-12-01

    Full Text Available Fenomena fluidisasi pada fluidized bed yaitu kecepatan minimum dan tekanan statis partikel merupakan hal fenomena yang penting dalam desain fluidized bed. Fenomena-fenomena tersebut dipengaruhi oleh banyak faktor dalam fluidized bed diantaranya massa jenis dan tinggi partikel di dalam fluidized bed. Penelitian ini menggunakan jenis partikel yang berbeda-beda dan rasio ketinggian partikel terhadap diameter fluidized bed (H/D dengan menggunakan Computational Fluid Dynamics. Partikel yang digunakan adalah partikel dengan jenis Geldart B yaitu glass beads (ρ=2600 kg/m3, ground walnut shell (ρ=1200 kg/m3 dan ground corncob (ρ=800 kg/m3, sedangkan rasio ketinggian partikel yang digunakan yaitu 0.5, 1, 1.5, 2, dan 2.5. Hasil penelitian menunjukkan bahwa massa jenis partikel berbanding lurus dengan kecepatan minimum fluidisasi dan ketinggian partikel tidak mempengaruhi kecepatan minimum fluidisasi.

  5. Utilization of fluidized bed material as a calcium and sulfur source for apples

    Energy Technology Data Exchange (ETDEWEB)

    Korcak, R.F.

    1984-01-01

    Fluidized bed material (FBM), a dry, high Ca, alkaline waste product which results from combining coal and limestone, was used as a Ca or S source or lime substitute in an established apple orchard (Malus domestica Borkh., cv. York Imperial) over a four year period. Treatment comparisons were made between FBM was applied at one or two times (1x or 2x) the soil lime requirement and CaCO/sub 3/ applied at the lime requirement (1x). Additionally, FBM 1x was compared to a combination treatment consisting of CaCO/sub 3/ plus gypsum to apply similar amounts of Ca and S. All treatments were also compared to an untreated control. No significant treatment comparisons were noted on leaf Ca levels, however, leaf Mg significantly decreased when FBM applied at the 1x or 2x level compared to CaCO/sub 3/ 1x. When FBM was compared with CaCO/sub 3/ plus gypsum there was a significant decrease in leaf Ca with FBM but no difference in leaf Mg. These effects were probably due to either a solubility difference between nutrients or to actual amount of Mg applied by the different sources. Leaf S levels were unaffected by treatments. Yields, fresh fruit weight and the incidence of cork spot were little affected by treatments. Soil extractable Mg, 1N NH/sub 4/Ac, was not a good prediction of leaf Mg content or Mg added to the soil. Only soil Al was significantly reduced, compared to the control, by the treatments among the metals studied (Zn, Mn, Cu, Cd, Pb and Al). FBM applied at twice the lime requirement (wt. basis) resulted in similar soil pH to CaCO/sub 3/ applied at the lime requirement. 14 references, 6 figures, 1 table.

  6. Analysis of longitudinal variations in North Pacific alkalinity

    Science.gov (United States)

    Fry, C.; Tyrrell, T.; Achterberg, E. P.

    2016-02-01

    Carbon measurements in the ocean lack the coverage of physical measurements, so approximate alkalinity is predicted where data is unavailable. Surface alkalinity in the North Pacific is poorly characterised by predictive algorithms. Understanding the processes affecting alkalinity in this area can improve the equations. We investigated the causes of regional variations in alkalinity using GLODAPv2. We tested different hypotheses for the causes of three longitudinal phenomena in surface ocean values of Alk*, a tracer of calcium carbonate cycling. These phenomena are: (a) an increase in Alk* from east to west at 50°N, (b) an increase in Alk* from west to east at 30°N, and (c) a lack of a strong increase in Alk* from west to east in the equatorial upwelling area. We found that the most likely cause of higher Alk* on the western side of the subpolar North Pacific (at 50°N) is that denser isopycnals with higher Alk* lie at shallower depths on the western side than the eastern side. At 30°N, the main cause of higher Alk* on the eastern side of the basin is upwelling along the continental shelf of southwestern North America. Along the equator, our analyses suggest that the absence of a strong east-west trend is because the more intense upwelling on the eastern side of the basin does not, under normal conditions, lead to strong elevation of Alk*. However, surface Alk* is more strongly elevated in the eastern Equatorial Pacific during negative phases of the El-Nino-Southern Oscillation, probably because the upwelled water comes from greater depth at these times.

  7. Thermofluid effect on energy storage in fluidized bed reactor

    Science.gov (United States)

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

    2016-05-01

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

  8. Fluidized bed granulation of an ordered powder mixture.

    Science.gov (United States)

    Thiel, W J; Nguyen, L T

    1982-11-01

    The phenomenon of ordered unit segregation is of paramount importance in determining the homogeneity of an ordered mixture. This problem can be avoided by using a monodisperse carrier, but it is uneconomic. The fluidized bed granulation of a 0.1% ordered mixture has been studied as a method of reducing the effects of segregation. The ordered units were stable when fluidized and no significant loss of the microfine adsorbed material occurred during processing. The distribution of the minor component in the granules was significantly more uniform than in the original ordered mixtures. The demixing potential (formula: see text) (where p = proportion of cohesive minor component and w is the weight % of carrier material in a particular size range) was used to quantify the distribution of the minor component as a function of particle size. DP is a coefficient of variation and can be directly compared with the specification standard deviation sigma A. Batches of granules were compressed into 100 or 350 mg tablets, containing approximately 100 and 350 micrograms of model drug substance. The weight and content coefficients of variation (c.v.) were determined for 20 tablets. All batches had a weight c.v. less than or equal to 1.5% and a content c.v. less than or equal to 4.6%. Granulation of an ordered mixture greatly reduces the potential for segregation to decrease the mixture homogeneity. It also provides a solution to the problems which may be encountered when the mixing of small quantities of cohesive materials during conventional fluidized bed granulation is attempted.

  9. Retrieval of fluidizable radioactive wastes from storage facilities

    International Nuclear Information System (INIS)

    2006-08-01

    This report provides guidance for strategic planning and implementation of resuspension and retrieval of stored fluid or fluidizable radioactive wastes. The potential risks associated with preparation and realization of these processes are included in the report, and lessons learned from previous applications are highlighted. Technological procedures and equipment used in various countries for resuspension and remobilization of stored fluidizable radioactive wastes are described in the attached annexes as potential options. Waste retrieval is a maturing technology of major importance now that Member States are moving forward in the responsible management of wastes by removal to safe interim storage or disposal. Retrieval of fluidizable wastes is a four-phase operation: (1) access to the waste, (2) mobilize the waste, (3) remove the waste; and (4) transfer the waste.This report divides successful retrieval of radioactive waste into two areas. The first area applies the concept of the waste retrieval as being the final component of a systematic process of old waste management. It also encompasses characterization as it applies to waste retrieval and downstream processes, including acceptance of wastes for treatment, conditioning, storage or disposal. It should be in conformity with national policy, as well as complying with international safety standards and environmental agreements. The second area of the report focuses on implementation of waste retrieval in a wide range of scenarios and using a wide range of retrieval approaches, equipment and technologies. Technical processes are further explained as part of the experience gained in advanced countries on the subject. A set of detailed retrieval technology descriptions by country is included as Annexes to this report. Thirteen experts from seven Member States that previously implemented, or have planned for the near future, significant resuspension and remobilization operations were involved in the preparation of

  10. Materials support for EPRI Fluidized-Bed Combustion Program

    International Nuclear Information System (INIS)

    Sethi, V.K.; Wright, I.G.

    1993-05-01

    This research project was intended to provide technical support for materials aspects of EPRI's U.C. Fluidized Bed Combustor Program. The scope of this support included participation in the EPRI FBC materials oversight panel, inspection of fluidized beds during forced or planned outages, analysis of materials failures and of associated deposits, participation in technical meetings involving fluidized bed materials. Volume I describes the results of exposing for approximately 5,000 hours in the Georgetown AFBC a number of surface modifications that had been reported to have promise in combating in-bed evaporator tube wastage. Some measures were applied to sample lengths of carbon-steel tubing, and installed as part of the in-bed evaporator tube bundle at Georgetown. These tubes are inspected periodically while still installed in the unit, and were finally cut out and subjected to detailed measurements and metallographic evaluation. The exposure at regular intervals throughout the bed of plain carbon-steel tubes that were honed and surface-ground allowed a baseline measurement of the wastage potential of this bed, which was high. Qualitatively, all but one of the protective measures tested reduced wastage. The unprotected tubes showed that wastage occurred mainly on the underside of the tubes, with maximum wear at the tube bottom. The protective measures that were exposed were densely studded tubes, fins and flow separators, fins and studs on the underside of the tube, and longitudinal rods. These surface modifications were exposed in the chromized and unchromized conditions, together with plain carbon-steel tubes that had been chromized. The tubes with fins and flow separators exhibited continued wastage on the underside between the flow separators, which was attributed in part to the steep inclination of the tubes in the bed. The plain, chromized tubes, together with the armored, chromized tubes, exhibited virtually no wastage of the tube surface nor of the armor

  11. Study of reactivity of fluidized bed nuclear reactor

    International Nuclear Information System (INIS)

    Rammsy, J.E.M.

    1985-01-01

    The reactor physics calculations of a 19 module Fluidized Bed Nuclear Reactor using Leopard and Odog codes are performed. The behaviour of the reactor was studied by calculating the reactivity of the reactor as a function of the parameters governing the operational and accidental conditions of the reactor. The effects of temperature, pressure, and vapor generation in the core on the reactivity are calculated. Also the start up behaviour of the reactor is analyzed. For the purpose of the study of a prototype research reactor, the calculations on a one module reactor have been performed. (Author) [pt

  12. Tunguska, 1908: the gas pouch and soil fluidization hypothesis

    Science.gov (United States)

    Nistor, I.

    2012-01-01

    The Siberian taiga explosion of 30 June 1908 remains one of the great mysteries of the 20th century: millions of trees put down over an area of 2200 km2 without trace of a crater or meteorite fragments. Hundred years of failed searches have followed, resulting in as many flawed hypothesis which could not offer satisfactory explanations: meteorite, comet, UFO, etc. In the author's opinion, the cause is that the energy the explorers looked for was simply not there! The author's hypothesis is that a meteoroid encountered a gas pouch in the atmosphere, producing a devastating explosion, its effects being amplified by soil fluidization.

  13. Study on transient of fluidized bed nuclear reactor

    International Nuclear Information System (INIS)

    Streck, E.E.

    1988-01-01

    The point kinetic equations for a Fluidized-Bed Nuclear Reactor are solved by the method of Hansen. Due to the time varying nature of the reactor volume, the equations have a non-conventional formulation (moving boundary problem), but the method of solution preserves its asymptotic convergence and efficiency characteristics under this formulation. A one dimensional and linearized thermal hydraulics feedback model was coupled to the point kinetic equations in order to obtain a more realistic representation of the reactor power. The resulting equations are solved by the Euler explicit method. (author)

  14. Product removal and solids transport from fluidized-bed calciners

    International Nuclear Information System (INIS)

    Grimmett, E.S.; Munger, D.H.

    1978-09-01

    Methods of removing the solid product from pilot-plant and production fluidized-bed calciners, and transporting product to underground storage vaults are reported here. Testing of dense-phase solids transport systems in test loops during development of a 15-cm-diam. and 30-cm-diam. calciner are described. A lean-phase solid transport system is used with the Waste Calcining Facility. The results of some recent tests done in a lean-phase transport system connected to the 30-cm-diam. calciner are included in this report

  15. 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.)

  16. Classification of tungsten powder by fluidization method and its application

    International Nuclear Information System (INIS)

    Li Khan-Guan'.

    1989-01-01

    Search for accessible in practice, the technological method to increase the level of control of the granulometric composition of tungsten powder and to increase quality of products and to prepare new materials is carried out. It is shown that the method of fluidization is effective and accessible in practice for tungsten powder (and other refractory metals and compounds) classification, that increases the level of control of the granulometric composition of the powder and thus - its quality, and that improves control of properties of tungsten and other refractory metal products

  17. Determination of viscosity in recirculating fluidized bed using radioactive tracer

    International Nuclear Information System (INIS)

    Silva, G.G. da.

    1986-01-01

    The use of radioactive tracer for measuring viscosity is proposed. The methodology relates the terminal velocity of a radioactive sphere in interior of fluid with the viscosity, which can be a fluidized bed or total flow of solids. The arrangement is composed by two γ detectors placed externally and along the bed. Both detectors are coupled by amplifier to electronic clock. The drop time of sphere between two detectors is measured. The bed viscosity two detectors is measured. The bed viscosity is calculated from mathematical correlations of terminal velocity of the sphere. (M.C.K.)

  18. Single particle behaviour in circulating fluidized bed combustors

    DEFF Research Database (Denmark)

    Erik Weinell, Claus

    1994-01-01

    of fuel particles in a boiler. A cold pilot scale model of a circulating fluidized bed combustor was used. Here sand was recirculated by means of air. Pressure measurements along the riser determined suspension density. A radioactive tracking facility to determined the dynamic picture of the particle...... trajectories in the simulated boiler. In the splash zone, closest to the secondary air inlet an exponential decay in the solids suspension density with the riser height was observed. A transport zone was characterized by an exponential decay in the solids suspension but with a smaller decay constant...

  19. Self-organization and chaos in a fluidized bed

    International Nuclear Information System (INIS)

    Daw, C.S.; Finney, C.E.A.; Vasudevan, M.; van Goor, N.A.; Nguyen, K.; Bruns, D.D.; Kostelich, E.J.; Grebogi, C.; Ott, E.; Yorke, J.A.

    1995-01-01

    We present experimental evidence that a complex system of particles suspended by upward-moving gas can exhibit low-dimensional bulk behavior. Specifically, we describe large-scale collective particle motion referred to as slugging in an industrial device known as a fluidized bed. As gas flow increases from zero, the bulk motion evolves from a fixed point to periodic oscillations to oscillations intermittently punctuated by ''stutters,'' which become more frequent as the flow increases further. At the highest flow tested, the behavior becomes extremely complex (''turbulent'')

  20. Pre-germinated Parboiled Brown Rice Drying Using Fluidization Technique

    OpenAIRE

    Nattapol Poomsa-ad; Lamul Wiset

    2012-01-01

    Pre-germinated parboiled brown rice or Khao hang (in Thai) is paddy which undergoing the processes of soaking, steaming, drying and dehusking to obtain the edible form for consumption. The objectives of this research were to study the kinetic of pre-germinated parboiled brown rice drying using fluidization technique and to study the properties of pre-germinated parboiled brown rice after drying. The dryings were performed at the different temperatures of 110, 120 and 130 oC at the bed depth o...

  1. Coal gasification fluidized bed (Winkler gasification) under pressure

    International Nuclear Information System (INIS)

    Anwer, J.; Boegner, F.

    1976-01-01

    Due to the 'oil crisis', the gasification of lignite and coal for the production of fuel and synthetic gas has reached increased importance. The present state of the Winkler gasification which has successfully operated for a long time is described. After the basic design of a Winkler gasification plant, the various chemical engineering problems are shown: the design characteristics of a fluidized bed, the reaction kinetics, the dependance of the products on the gasification pressure, and the economics of the process. Finally, the development trend in the USA and the future possibility of heating by nuclear heat is dealt with. (orig.) [de

  2. Effect of vortex orifice air distributor on granule growth in conical fluidized bed granulation with bottom entry spray

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Y.; Sekiguchi, I. [Chuo Univ., Tokyo (Japan). Faculty of Science and Engineering

    2000-02-01

    This investigation is undertaken to obtain information on the effect of vortex orifice air distributors on the granule growth in conical fluidized bed granulation with a bottom entry spray. The five types of vortex orifice distributors suitable for a strong swirling air supply at the base of the conical bed were prepared. Although all these orifices consisted of four tangential injection nozzles with the same opening, the opening size of the air injection nozzle in each of the orifices was different. Intensity of the air injection nozzle torque within the vortex orifice was measured by a torque balance method. The granule formation of fluidising lactose particles in the process of size-enlargement was carried out by spraying an aqueous HPC solution into the bed where the moisture content of granules was maintained at or below 0.30 wt %. As a result, granule growth in the bed could be precisely controlled by changes in the air injection nozzle torques arising from the vortex orifice distributor. The extent of granule growth, namely the granule growth conversion increasing with accumulated content of HPC in the bed particles during the operating time decreased according to the air injection nozzle torque within the vortex orifice. Using these process variables, granule growth conversion could be arranged experimentally. It is finally found that one of the features of the proposed air distributor is useful for size-control of granule products in the conical fluidized bed granulation with a bottom entry spray. (author)

  3. Ocean Acidification: Coccolithophore's Light Controlled Effect on Alkalinity

    Science.gov (United States)

    Dobbins, W.

    2015-12-01

    Coccolithophorids, which play a significant role in the flux of calcite and organic carbon from the photic region to deeper pelagic and benthic zones, are potentially far more useful than siliceous phytoplankton for ocean fertilization projects designed to sequester CO2. However, the production of H+ ions during calcification (HCO3 + Ca+ —> CaCO3 + H+) has resulted in localized acidification around coccolithophore blooms. It has been hypothesized that under the correct light conditions photosynthesis could proceed at a rate such that CO2 is removed in amounts equimolar or greater than the H+ produced by calcification, allowing stable or increasing alkalinity despite ongoing calcification. Previously, this effect had not been demonstrated under laboratory conditions. Fifteen Emiliania huxleyi cultures were separated into equal groups with each receiving: 0, 6, 12, 18, or 24 hours of light each day for 24 days. Daily pH, cell density, and temperature measurements revealed a strong positive correlation between light exposure and pH, and no significant decline in pH in any of the cultures. Alkalinity increases were temperature independent and not strongly correlated with cell density, implying photosynthetic removal of carbon dioxide as the root cause. The average pH across living cultures increased from 7.9 to 8.3 over the first week and changed little for the reminder of the 24-day period. The results demonstrate coccolithophorids can increase alkalinity across a broad range of cell densities, despite the acidification inherent to the calcification process. If the light-alkalinity effect reported here proves scalable to larger cultures, Emiliania huxleyi are a strong candidate for carbon sequestration via targeted ocean fertilization.

  4. Design requirements for uranium ion exchange from acidic solutions in a fluidized system

    International Nuclear Information System (INIS)

    Traut, D.E.; Nichols, I.L.; Seidel, D.C.

    1974-01-01

    A fluidized, countercurrent ion-exchange system was developed, operated, and evaluated by the Bureau of Mines in support of its objective to help assure an adequate uranium supply for future national needs. The system consisted of integrated multiple-compartment absorption and elution columns in which the solution flows are continuous, except for short periods when resin increments are withdrawn. The exchange of uranyl sulfate between a simulated acid-leach-uranium solution and a strong-base, ion-exchange resin was studied, together with subsequent elution using an acidified sodium chloride solution. The effects of the number of compartments, compartment height, amount of resin withdrawal, solution flow rate, and column diameter were investigated. Also examined were the kinetic and equilibrium relationships for the absorption and elution steps. The experimental data indicate a strong interdependence between variables. Solution retention time appears to be a major limiting variable in the absorption process, while resin residence time is the determining factor in the elution process. The columns system was efficient over a range of conditions, but close control was needed for optimum operation

  5. The relationship of fluidized bed technology to the U.S. Clean Coal Technology demonstration program

    International Nuclear Information System (INIS)

    Weth, G.; Geffken, J.; Huber, D.A.

    1991-01-01

    Fluidized Bed Combustion projects (both AFBCs and PFBCs) have a prominent role in the US DOE Clean Coal Technology (CCT) Program. This program has the successful commercialization of these technologies as its primary objective and this is the basic criterion for government funding and participation in the development and demonstration of the technologies. Under the CCT program the US DOE is actively involved in the development and operation of three Fluidized Bed Technology projects, NUCLA, TIDD, and SPORN, and is in the negotiation stage on others, Dairyland, Nichols and Tallahassee. All of these projects, along with the operating information on fluidized beds in the industrial sector, will provide a basis for evaluating future utilization of Fluidized Bed Technology in the market place. Impacting upon further utilization will be the time-frame and the Clean Air Act Amendments of 1990. This paper presents the results of a study to ascertain the commercial readiness of Fluidized Bed Technology to meet the emissions and time-frame requirements of the Clean Air Act Amendments of 1990. Specifically addressed are: Commercialization criteria/factors which candidate and/or existing CCTs must achieve in order to gain market acceptance. The status of Fluidized Bed Technology in achieving these commercialization criteria for market acceptance (industrial and utility) consistent with the time frame of the Clean Air Act Amendments of 1990. Recommendations of commercialization criteria for future fluidized bed CCT demonstration projects

  6. Thermal stability in a newly designed columnar-conical fluidized bed for combustion of rice husk

    Energy Technology Data Exchange (ETDEWEB)

    Rozainee, M.; Salema, A.A.; Ngo, S.P.; Chye, G.B. [Malaysian Technological Univ., Johor Bahru (Malaysia). Dept. of Chemical Engineering

    2006-07-01

    The effects of fluidizing and liquid propane gas (LPG) flow rates on thermal stability of a fluidized bed were examined. The aim of the study was to hybridize a columnar and conical fluidized bed (CCFB) in order to encourage the combustion of low-calorific fuels such as rice husks. Experiments were conducted to examine the thermal stability of the CCFB. Premixed primary air and liquid propane gas (LPG) was fed into the bed in order to verify its thermal stability. Temperature profiles of the combustor and bed were measured. The impact of the fluidizing velocity and LPG flow rate on the temperature profile was examined in order to analyze the influence of the fluidizing velocity and LPG rate on combustion rates. Results of the study showed that the combustion of the CCFB was sustained at a fluidizing velocity of 1.5 U{sub mf} and at an LPG flow rate of 8 liters per minute. Results of the study showed that fluidizing velocity played an important role on the thermal stability of the bed. It was concluded that the thermal stability of the combustor is sufficient for the CCFB. 13 refs., 2 tabs., 5 figs.

  7. Chaotic behavior in a hydrodynamic model of a fluidized bed reactor

    International Nuclear Information System (INIS)

    Schouten, J.C.; van den Bleek, C.M.

    1991-01-01

    Recent preliminary experimental studies using time-series analysis have demonstrated that the multi-phase flow in fluidized bed reactors can be characterized as chaotic. In the present paper, it is therefore argued that the chaotic time-dependence of fluidization is a characteristic feature which should be included in scaling rules for fluidized bed reactors. For example, the similarity groups applied in dimensionless fluidized bed scaling should be improved by extending them with functions of the relevant numbers from chaos theory, such as the correlation and embedding dimension or the maximum Lyapunov exponent. This requires that the dependence of these numbers on fluidization parameters must be theoretically and experimentally investigated. The concept of chaos in fluidization also requires that the classical, empirically developed, hydrodynamic models that are applied in fluidized bed scaling are amended to include time-dependence, non-linearity as well as a sufficient level of complexity before they can predict any chaotic behavior. An example is given of chaotic behavior generated in the classical counter-current flow model according to Van Deemter by writing the upwards solids velocity as a harmonic oscillating function of time. A low-dimensional strange attractor is found, embedded in two-dimensional phase space, of which the correlation dimension depends on the solids exchange coefficient

  8. Scaling up of the fluidized bed granulation process.

    Science.gov (United States)

    Rambali, B; Baert, L; Massart, D L

    2003-02-18

    The scaling up of a fluidized bed granulation process from small scale to production scale is often done empirically in the pharmaceutical industry. In this study, a more practical and systematic method was developed in order to achieve a similar granule size in the scaled up fluid bed. The scaling up is based on the relative droplet size, and the powder bed moisture content at the end of the spraying cycle. The present study describes the scaling up of the fluidized granulation process from small (5 kg scale) to medium (30 kg scale) and to production fluid bed scale (120 kg scale). The granulation process is scaled up with as target a geometric mean granule size of 400 microm. First, the effect of the relative droplet size on the granule size was investigated in the different fluid beds. The effect of the change in relative droplet size on the granule size was different for each fluid bed. Second, experimental design is applied on the small and the medium fluid scale, and regression models for the granule size are proposed in order to scale up the granulation process on the small to medium scale. The granulation process was also successful by scaling-up to the large fluid bed, considering only the relative droplet size.

  9. Co-combustion of waste materials using fluidized bed technology

    Energy Technology Data Exchange (ETDEWEB)

    M. Lopes; I. Gulyurtlu; P. Abelha; T. Crujeira; D. Boavida; I. Cabrita [INETI-DEECA, Lisbon (Portugal)

    2004-07-01

    There is growing interest in using renewable fuels in order to sustain the CO{sub 2} accumulation. Several waste materials can be used as coal substitutes as long as they contain significant combustible matter, as for example MSW and sewage sludge. Besides the outcome of the energetic valorization of such materials, combustion must be regarded as a pre-treatment process, contributing to the safe management of wastes. Landfilling is an expensive management option and requires a previous destruction of the organic matter present in residues, since its degradation generates greenhouse gases and produces acidic organic leachates. Fluidized bed combustion is a promising technology for the use of mixtures of coal and combustible wastes. This paper presents INETI's experience in the co-combustion of coal with this kind of residues performed in a pilot fluidized bed. Both the RDF (from MSW and sewage sludge) and sewage sludge combustion problems were addressed, relating the gaseous emissions, the behaviour of metals and the leachability of ashes and a comparison was made between co-combustion and mono-combustion in order to verify the influence of the utilization of coal. 9 refs., 1 fig., 3 tabs.

  10. Microwave fluidized-bed detoxification of hazardous waste

    Energy Technology Data Exchange (ETDEWEB)

    Varma, R.

    1991-11-01

    Our ongoing research and development (R D) work focuses on demonstrating the technical feasibility of total detoxification of C1HC'' hazardous waste by using microwave energy. In addition, we investigated the capability of nahacolite for in-bed scavenging of HC1 and found it to be very effective. So far, detoxification of halocarbon vapor and liquid waste forms has been achieved. Microwave energy heats and activates the particulates of silicon carbide (SiC) and promotes chemical interactions, facilitating total detoxification of chlorinated hydrocarbons (TCEs) in an air-stream over SiC-fluidized beds under mild (<600{degrees}) conditions. The SiC promotes surface-enhanced reactions and also is a heating transfer medium. These microwave-assisted processes appear to be extremely energy efficient. The Los Alamos National Laboratory (LANL) team can demonstrate the microwave fluidized bed (MFB) technology for total detoxification of halocarbon waste streams. The technology is applicable for treatment of hazardous waste at DOE sites. 5 refs., 5 figs.

  11. On fluidization of borosilicate glasses in intense radiation fields - 16055

    International Nuclear Information System (INIS)

    Ojovan, Michael; Moebus, Guenter; Tsai, Jim; Cook, Stuart; Yang, Guang

    2009-01-01

    The viscosity is rate-limiting for many processes in glassy materials such as homogenisation and crystallisation. Changes in the viscous flow behaviour in conditions of long-term irradiation are of particular interest for glassy materials used in nuclear installations as well as for nuclear waste immobilising glasses. We analyse the viscous flow behaviour of oxide amorphous materials in conditions of electron-irradiation using the congruent bond lattice model of oxide materials accounting for the flow-mediating role of broken bonds termed configurons. An explicit equation of viscosity was obtained which is in agreement with experimental data for non-irradiated glasses and shows for irradiated glasses, first, a significant decrease of viscosity, and, second, a stepwise reduction of the activation energy of flow. An equation for glass-transition temperature was derived which shows that irradiated glasses have lower glass transition temperatures. Intensive electron irradiation of glasses causes their fluidization due to non-thermal bond breaking and can occur below the glass transition temperature. Due to surface tension forces fluidization of glasses at enough high electron flux densities can result in modification of nano-size volumes and particles such as those experimentally observed under TEM electron beams. (authors)

  12. 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.

  13. Multiscale probability distribution of pressure fluctuations in fluidized beds

    International Nuclear Information System (INIS)

    Ghasemi, Fatemeh; Sahimi, Muhammad; Reza Rahimi Tabar, M; Peinke, Joachim

    2012-01-01

    Analysis of flow in fluidized beds, a common chemical reactor, is of much current interest due to its fundamental as well as industrial importance. Experimental data for the successive increments of the pressure fluctuations time series in a fluidized bed are analyzed by computing a multiscale probability density function (PDF) of the increments. The results demonstrate the evolution of the shape of the PDF from the short to long time scales. The deformation of the PDF across time scales may be modeled by the log-normal cascade model. The results are also in contrast to the previously proposed PDFs for the pressure fluctuations that include a Gaussian distribution and a PDF with a power-law tail. To understand better the properties of the pressure fluctuations, we also construct the shuffled and surrogate time series for the data and analyze them with the same method. It turns out that long-range correlations play an important role in the structure of the time series that represent the pressure fluctuation. (paper)

  14. Fluidized bed gasification of waste-derived fuels.

    Science.gov (United States)

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

    2010-07-01

    Five alternative waste-derived fuels obtained from municipal solid waste and different post-consumer packaging were fed in a pilot-scale bubbling fluidized bed gasifier, having a maximum feeding capacity of 100 kg/h. The experimental runs utilized beds of natural olivine, quartz sand or dolomite, fluidized by air, and were carried out under various values of equivalence ratio. The process resulted technically feasible with all the materials tested. The olivine, a neo-silicate of Fe and Mg with an olive-green colour, has proven to be a good candidate to act as a bed catalyst for tar removal during gasification of polyolefin plastic wastes. Thanks to its catalytic activity it is possible to obtain very high fractions of hydrogen in the syngas (between 20% and 30%), even using air as the gasifying agent, i.e. in the most favourable economical conditions and with the simplest plant and reactor configuration. The catalytic activity of olivine was instead reduced or completely inhibited when waste-derived fuels from municipal solid wastes and aggregates of different post-consumer plastic packagings were fed. Anyhow, these materials have given acceptable performance, yielding a syngas of sufficient quality for energy applications after an adequate downstream cleaning. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  15. Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-29

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

  16. Histochemistry of placental alkaline phosphatase in preeclampsia

    OpenAIRE

    Shevade, Sapna Prashant; Arole, Vasanti; Paranjape, Vaishali Mohan; Bharambe, Vaishaly Kishore

    2016-01-01

    Objectives: Placental alkaline phosphatase (PALP) is synthesized in placenta and increases with gestational age. Alkaline phosphatase supports pregnancy and could play an essential role in nutrient supply and growth of the fetus. Preeclampsia is a systemic disorder which affects 5 to 7 percent of women worldwide and is a major cause for maternal and neonatal morbidity and mortality. As it has a major role in fetal growth, nutrition and defense mechanism study of alkaline phosphatase enzymatic...

  17. Analysis of the pressure fluctuations in binary solids circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yong-guo; Tian, Zi-ping; Miao, Zheng-qing [School of Mechanical and Power Engineering, Shanghai JiaoTong University, Dongchuan Road 800, Shanghai 200240 (China)

    2006-03-15

    Pressure fluctuations are often selected to analyze the dynamic changes in the fluidized bed. Many researchers in the field of fluidization have adopted many methods to analyze the pressure signals in fluidized beds, such as statistical analysis (in time domain), frequency analysis (in frequency domain) and non-linear analysis (such as chaotic method). There are many literatures concentrated on statistical analysis in the fluidization field since this method can display the distribution density of the pressure fluctuations. In this study, the pressure fluctuations on the bed wall at different bed heights in the cold two dimensional (2-D) circulating fluidized bed (200x30x1200mm{sup 3}) were sampled. The colophony, millet and 20% millet plus 80% colophony were selected as bed materials. The pressure signals were analyzed by means of statistical methods. The correlation equations between the pressure signals and fluidization parameters were obtained under different operational conditions. Finally, comparisons between the single solid and binary solids 2-D circulating fluidized beds were investigated deeply. Two parameters, K{sub 1} (=0.54(u-u{sub mf}){sup 0.4}h{sup 0.8}/g{sup 0.2}) and K{sub 2} (={sigma}{sub b}/(r{sub s}g(1-{epsilon}{sub mf}))), were selected to characterize the fluidization mechanism. It was found that the relationships between K{sub 2} and K{sub 1} among the single solid and binary solids circulating fluidized beds vary a great deal. (author)

  18. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D

    1999-01-01

    .... The subject low cost alkaline electrochemical capacitor designs are based upon titanium nitride electrodes which exhibit 125 mF/sq cm surface capacitance density and remarkable electrochemical...

  19. Corrosion of copper in alkaline chloride environments

    International Nuclear Information System (INIS)

    King, F.

    2002-08-01

    The available literature information on the corrosion and electrochemical behaviour of copper in alkaline environments has been reviewed. The purpose of the review was to assess the impact of an alkaline plume from cementitious material on the corrosion behaviour of a copper canister in an SKB-3 type repository. The effect of the evolution of the environmental conditions within the repository have been considered, including the effects of temperature, redox conditions, pore-water salinity and pH. If the pore-water pH increases prior to the establishment of anoxic conditions, the canister surface will passivate as the pore-water pH exceeds a value of ∼ pH 9. Passivation will result from the formation of a duplex Cu 2 O/Cu(OH) 2 film. The corrosion potential will be determined by the equilibrium potential for the Cu 2 O/Cu(OH) 2 couple under oxic conditions, or by the Cu/Cu 2 O redox couple under anoxic conditions (in the absence of sulphide). Pitting corrosion is only likely to occur early in the evolution of the repository environment, whilst the canister is still relatively cool ( 2 available to support localised corrosion, and prior to the increase in pore-water pH and salinity. The subsequent increase in canister surface temperature, pore-water pH and salinity, and decrease in O 2 will make pit initiation less likely, although the canister will remain passive provided the pore-water pH is maintained above pH 9. The higher the pore-water pH, the more strongly the canister is passivated and the less likely the surface is to undergo localised attack. If the pore-water salinity increases prior to the increase in pH, there could be a period of active canister corrosion before passivation occurs.Under these circumstances, the corrosion potential will be a true mixed potential, determine by the relative kinetics of Cu dissolution as CuCl 2 - and of the reduction of O 2 . The development of anoxic conditions and an increase in pore-water sulphide concentration will

  20. Progress of research on the influence of alkaline cation and alkaline solution on bentonite properties

    International Nuclear Information System (INIS)

    Ye Weimin; Zheng Zhenji; Chen Bao; Chen Yonggui

    2011-01-01

    Based on the previous laboratory studies and numerical simulation on bentonite in alkaline environments, the effects of alkaline cation and alkaline solution on mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite are emphasized in this paper, temperature, pH values and concentration are discussed as main affecting factors. When bentonite is exposed to alkaline cation or alkaline solution, microstructure of bentonite will be changed due to the dissolution of montmorillonite and the formation of secondary minerals, which results in the decrease of swelling pressure. The amount of the reduction of swelling pressure depends on the concentration of alkaline solution. Temperature, polyvalent cation, salinity and concentration are the main factors affecting hydraulic properties of bentonite under alkaline conditions. Therefore, future research should focus on the mechanism of coupling effects of weak alkaline solutions on the mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite under different temperatures and different pH values. (authors)

  1. Alkaline and alkaline earth metal phosphate halides and phosphors

    Science.gov (United States)

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

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

    Science.gov (United States)

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

    2000-11-01

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

  3. A comparison of granules produced by high-shear and fluidized-bed granulation methods.

    Science.gov (United States)

    Morin, Garett; Briens, Lauren

    2014-08-01

    Placebo granules were manufactured by both wet high-shear and fluidized-bed techniques. The granules were compared based on size, shape, surface morphology, and a variety of different flowability measurements. This comparison showed that granule formation and growth were different, with induction growth for high-shear granulation and steady growth for fluidized-bed granulation. Final granules from high-shear granulation were more spherical and dense compared with the irregular granules from fluidized-bed granulation. The high-shear granules demonstrated better overall flow properties.

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

    Directory of Open Access Journals (Sweden)

    S. Heinrich

    2005-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Iliev Vasil

    2014-12-01

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

  6. Fluidized bed ash and passive treatment reduce the adverse effects of acid mine drainage on aquatic organisms.

    Science.gov (United States)

    Porter, Clint M; Nairn, Robert W

    2010-10-15

    Elevated concentrations of acidity and metals in acid mine drainage (AMD) may be effectively addressed by active and passive treatment technologies. However, typical evaluations consider only chemical water quality with little if any regard for biological metrics. Robust evaluations including both chemical and biological indicators of water quality improvement are needed. In this study, injection of alkaline fluidized bed ash (FBA) into a flooded underground coal mine was coupled with a five-cell passive treatment system to ameliorate an abandoned AMD discharge in eastern Oklahoma. The passive system included process units promoting both aerobic and anaerobic treatment mechanisms. Resulting water quality changes and biological responses were evaluated. Organisms of two distinct functional groups (the filter-feeding mollusk Corbicula fluminea and the wide-spectrum feeding fish Lepomis macrochirus) were exposed to mine waters in several treatment cells. The combination of treatment technologies was hypothesized to limit potential negative effects on these aquatic organisms. Tissues were harvested and analyzed for concentrations of several metals (Al, Fe, Mn, Mg, Ca, Ni, Cu and Zn) of interest. Organismal responses, such as hepatosomatic index, condition factor, and condition index, did not vary significantly among organisms exposed within different treatment cells when compared to non-AMD impaired waters. Metal tissue accumulation trends, compared to aqueous concentrations, were observed for Fe, Ni and Zn. Exposure experiments with these two organisms indicated that FBA introductions coupled with passive treatment decreased the potential adverse effects of AMD to biological systems. Copyright © 2010 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Wang, Haigang; Yang, Wuqiang

    2011-10-01

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

  8. Alkaline azide mutagenicity in cowpea

    International Nuclear Information System (INIS)

    Mahna, S.K.; Bhargava, Anubha; Mohan, Lalit

    1990-01-01

    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10 -6 , 10 -5 , 10 -4 and 10 -3 M) of sodium azide (NaN 3 ) for 4 hours at 28± 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M 2

  9. Combustion en lit fluidisé Fluidized-Bed Combustion

    Directory of Open Access Journals (Sweden)

    Chrysostome G.

    2006-11-01

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

  10. catalysed oxidation of atenolol by alkaline permanganate

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Kinetics of ruthenium (III) catalyzed oxidation of atenolol by permanganate in alkaline medium at constant ionic strength of 0⋅30 mol dm3 has been studied spectrophotometrically using a rapid kinetic accessory. Reaction between permanganate and atenolol in alkaline medium exhibits 1 : 8 stoichiometry.

  11. Increased liver alkaline phosphatase and aminotransferase ...

    African Journals Online (AJOL)

    The effect of daily, oral administration of ethanolic extract of Khaya senegalensis stem bark (2mg/kg body weight) for 18days on the alkaline phosphatase, aspartate and alanine aminotransferase activities of rat liver and serum were investigated. Compared with the control, the activities of liver alkaline phosphatase (ALP), ...

  12. Alkaline Phosphatases From Camel Small Intestine | Fahmy ...

    African Journals Online (AJOL)

    Camel intestinal alkaline phosphatase have been purified and characterized. The purification was carried out by chromatography on DEAE-cellulose. Five intestinal alkaline phosphatase isoenzymes (IAP1 to IAP5) were obtained. IAP2 and IAP5 with the highest activity levels were purified to homogeneity by Sephacryl ...

  13. Handbook of Indigenous Foods Involving Alkaline Fermentation

    NARCIS (Netherlands)

    Sarkar, P.K.; Nout, M.J.R.

    2014-01-01

    This book details the basic approaches of alkaline fermentation, provides a brief history, and offers an overview of the subject. The book discusses the diversity of indigenous fermented foods involving an alkaline reaction, as well as the taxonomy, ecology, physiology, and genetics of predominant

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

    CSIR Research Space (South Africa)

    Mathekga, HI

    2016-06-01

    Full Text Available Presently, there is no detailed review that summarizes the current knowledge status on oxy-fuel combustion in fluidized bed combustors. This paper reviewed the existing literature in heat transfer, char combustion and pollutant emissions oxy...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-03-01

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

  17. Mathematical modeling of a fluidized bed rice husk gasifier: Part 3 -- Model verification

    Energy Technology Data Exchange (ETDEWEB)

    Mansaray, K.G.; Ghaly, A.E.; Al-Taweel, A.M.; Ugursal, V.I.; Hamdullahpur, F.

    2000-04-01

    The validity of the two-compartment model developed for fluidized bed gasification of biomass was tested using experimental data obtained from a dual-distributor-type fluidized bed gasifier. The fluidized bed was operated on rice husks at various bed heights (19.5, 25.5, and 31.5 cm), fluidization velocities (0.22, 0.28, and 0.33 m/s), and equivalence ratios (0.25, 0.30, and 0.35). The model gave reasonable predictions of the core, annulus, and exit temperatures as well as the mole fractions of the combustible gas components and product gas higher heating value, except for the overall carbon conversion, which was overestimated. This could be attributed to uncertainties in the sampling procedure.

  18. Mathematical modeling of a fluidized bed rice husk gasifier: Part 3 - Model verification

    Energy Technology Data Exchange (ETDEWEB)

    Mansaray, K.G.; Ghaly, A.E.; Al-Taweel, A.M.; Ugursal, V.I.; Hamdullahpur, F.

    2000-03-01

    The validity of the two-compartment model developed for fluidized bed gasification of biomass was tested using experimental data obtained from a dual-distributor-type fluidized bed gasifier. The fluidized bed was operated on rice husks at various bed heights (19.5, 25.5, and 31.5 cm), fluidization velocities (0.22, 0.28, and 0.33 m/s), and equivalence ratios (0.25, 0.30, and 0.35). The model gave reasonable predictions of the core, annulus, and exit temperatures as well as the mole fractions of the combustible gas components and product gas higher heating value, except for the overall carbon conversion, which was overestimated. This could be attributed to uncertainties in the sampling procedure. (Author)

  19. Operating experience and data on revolving type fluidized bed incineration plants

    International Nuclear Information System (INIS)

    Nakayama, J.

    1990-01-01

    In refuse incinerators operating by revolving fluidization (Revolving Type Fluidized Bed Incinerator) a broad range of wastes, from low caloric refuse of high moisture content to high caloric value material including a wide variety of plastics, can be incinerated at high efficiency because the unit is outstanding in terms of distribution of waste in the incinerator bed and uniformity of heat. In addition, its vigorous revolving fluidization action is very effective in pulverizing refuse, so even relatively strict emission standards can be met without fine pre-shredding. Residues are discharged in a clean, dry form free of putrescible material. Data on practical operation of the revolving fluidized bed incinerator are presented in this paper

  20. A grid-independent EMMS/bubbling drag model for bubbling and turbulent fluidization

    DEFF Research Database (Denmark)

    Luo, Hao; Lu, Bona; Zhang, Jingyuan

    2017-01-01

    The EMMS/bubbling drag model takes the effects of meso-scale structures (i.e. bubbles) into modeling of drag coefficient and thus improves coarse-grid simulation of bubbling and turbulent fluidized beds. However, its dependence on grid size has not been fully investigated. In this article, we adopt...... a periodic domain show the new drag model is less sensitive to grid size because of the additional dependence on local slip velocity. When applying the new drag model to simulations of realistic bubbling and turbulent fluidized beds, we find grid-independent results are easier to obtain for high......-velocity turbulent fluidized bed cases. The simulation results indicate that the extended EMMS/bubbling drag model is a potential method for coarse-grid simulations of large-scale fluidized beds....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-10-17

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

  2. Alkaline Phosphatase, Soluble Extracellular Adenine Nucleotides, and Adenosine Production after Infant Cardiopulmonary Bypass.

    Science.gov (United States)

    Davidson, Jesse A; Urban, Tracy; Tong, Suhong; Twite, Mark; Woodruff, Alan; Wischmeyer, Paul E; Klawitter, Jelena

    2016-01-01

    Decreased alkaline phosphatase activity after infant cardiac surgery is associated with increased post-operative cardiovascular support requirements. In adults undergoing coronary artery bypass grafting, alkaline phosphatase infusion may reduce inflammation. Mechanisms underlying these effects have not been explored but may include decreased conversion of extracellular adenine nucleotides to adenosine. 1) Evaluate the association between alkaline phosphatase activity and serum conversion of adenosine monophosphate to adenosine after infant cardiac surgery; 2) assess if inhibition/supplementation of serum alkaline phosphatase modulates this conversion. Pre/post-bypass serum samples were obtained from 75 infants alkaline phosphatase and CD73. Low and high concentration 13C5-adenosine monophosphate (simulating normal/stress concentrations) were used. Effects of alkaline phosphatase supplementation on adenosine monophosphate clearance were also assessed. Changes in serum alkaline phosphatase activity were strongly correlated with changes in 13C5-adenosine production with or without CD73 inhibition (r = 0.83; palkaline phosphatase activity (≤80 U/L) generated significantly less 13C5-adenosine, particularly in the presence of high concentration 13C5-adenosine monophosphate (10.4μmol/L vs 12.9μmol/L; p = 0.0004). Inhibition of alkaline phosphatase led to a marked decrease in 13C5-adenosine production (11.9μmol/L vs 2.7μmol/L; palkaline phosphatase or high dose bovine intestinal alkaline phosphatase doubled 13C5-adenosine monophosphate conversion to 13C5-adenosine (pAlkaline phosphatase represents the primary serum ectonucleotidase after infant cardiac surgery and low post-operative alkaline phosphatase activity leads to impaired capacity to clear adenosine monophosphate. AP supplementation improves serum clearance of adenosine monophosphate to adenosine. These findings represent a potential therapeutic mechanism for alkaline phosphatase infusion during cardiac

  3. Selective phenol methylation to 2,6-dimethylphenol in a fluidized bed of iron-chromium mixed oxide catalyst with o-cresol circulation.

    Science.gov (United States)

    Zukowski, Witold; Berkowicz, Gabriela; Baron, Jerzy; Kandefer, Stanisław; Jamanek, Dariusz; Szarlik, Stefan; Wielgosz, Zbigniew; Zielecka, Maria

    2014-01-01

    2,6-dimethylphenol (2,6-DMP) is a product of phenol methylation, especially important for the plastics industry. The process of phenol methylation in the gas phase is strongly exothermic. In order to ensure good temperature equalization in the catalyst bed, the process was carried out using a catalyst in the form of a fluidized bed - in particular, the commercial iron-chromium catalyst TZC-3/1. Synthesis of 2,6-dimethylphenol from phenol and methanol in fluidized bed of iron-chromium catalyst was carried out and the fluidization of the catalyst was examined. Stable state of fluidized bed of iron-chromium catalyst was achieved. The measured velocities allowed to determine the minimum flow of reactants, ensuring introduction of the catalyst bed in the reactor into the state of fluidization. Due to a high content of o-cresol in products of 2,6-dimethylphenol synthesis, circulation in the technological node was proposed. A series of syntheses with variable amount of o-cresol in the feedstock allowed to determine the parameters of stationary states. A stable work of technological node with o-cresol circulation is possible in the temperature range of350-380°C, and o-cresolin/phenolin molar ratio of more than 0.48. Synthesis of 2,6-DMP over the iron-chromium catalyst is characterized by more than 90% degree of phenol conversion. Moreover, the O-alkylation did not occur (which was confirmed by GC-MS analysis). By applying o-cresol circulation in the 2,6-DMP process, selectivity of more than 85% degree of 2,6-DMP was achieved. The participation levels of by-products: 2,4-DMP and 2,4,6-TMP were low. In the optimal conditions based on the highest yield of 2,6-DMP achieved in the technological node applying o-cresol circulation, there are 2%mol. of 2,4-DMP and 6%mol. of 2,4,6-TMP in the final mixture, whereas 2,4,6-TMP can be useful as a chain stopper and polymer's molar mass regulator during the polymerization of 2,6-DMP.

  4. Rb-Sr age of the Sivamalai alkaline complex, Tamil Nadu

    International Nuclear Information System (INIS)

    Subba Rao, T.V.; Narayana, B.L.; Gopalan, K.

    1994-01-01

    The Sivamalai alkaline complex comprises ferro-, pyroxene- hornblende-and nepheline-syenites. Field relations show that the nepheline syenites followed the emplacement of non-feldspathoidal syenites. Mineralogical data on the syenite suite have been reviewed. The Sivamalai alkaline rocks are not strongly enriched in rare-earth elements like most miaskites. Rb-Sr isotopic analyses of a suite of six samples from the various members of the complex define an isochron corresponding to an age of 623 ± 21 Ma (2σ) and initial Sr ratio of 0.70376 ± 14 (2σ). This is consistent with a model of fractional crystallization of a parent magma derived from an upper mantle source with apparently no isotopic evidence for more than one magma source for the complex. The Sivamalai alkaline complex represents a Pan-African alkaline magmatic event in the southern granulite terrane of peninsular India. (author). 26 refs., 4 figs., 4 tabs

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

    Science.gov (United States)

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

    2000-01-01

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

  6. Computational Fluid Dynamics Simulation of Fluidized Bed Polymerization Reactors

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-01-01

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

  7. 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.

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

    Directory of Open Access Journals (Sweden)

    L. L. Oliveira

    2010-12-01

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

  9. Application of fluidization to separate packaging waste plastics.

    Science.gov (United States)

    Carvalho, M Teresa; Ferreira, Célia; Portela, Antía; Santos, João Tiago

    2009-03-01

    The objective of the experimental work described in this paper is the study of the separation of PS (polystyrene) from PET (polyethylene terephthalate) and PVC (polyvinyl chloride) from drop-off points using a fluidized bed separator. This is a low-cost process commonly used in the hydro-classification of mineral ores. Firstly, experimental tests were carried out with artificial granulated samples with different grain sizes, types and sources of plastic ("separability tests"). The particle settling velocities were determined under different operating conditions. Then, based on the results, the laboratory tests continued with real mixtures of waste plastics ("separation tests") and the efficiency of the process was evaluated. From a PET-rich mixture, a concentrate of PS with a 75% grade in PS was produced while the underflow was quite clear from PS (grade less than 0.5% in PS).

  10. Bubbling fluidized bed boiler for Vanaja power plant

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-07-01

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

  11. Fluidized bed incineration of a slurry waste from caprolactam production

    Energy Technology Data Exchange (ETDEWEB)

    Cammarota, A.; D' Amore, M.; Donsi, G.; Massimilla, L.

    1980-08-01

    Caprolactam tails are a slurry waste produced in the SNIA process for the synthesis of caprolactam. They contain about 65% water, 25% ash and 10% combustible matter. The ashes are low melting, due to the presence of sodium compounds. The incineration of this waste is carried out at temperatures below 600/sup 0/C in beds of silica sand, using a laboratory scale apparatus with a 40 mm ID fluidization column. Variables investigated include sand particle size, slurry flow rate, bed temperature, bed height. The concentrations of CO/sub 2/ and CO are determined continuously in the flue gases. Bed solids are sampled periodically to determine the carbon content. Results of experiments show that the low temperature incineration on a bed of inert solids is a useful technique for the disposal of caprolactam tails. 8 refs.

  12. Technical evaluation: pressurized fluidized-bed combustion technology

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

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

  14. A numerical model of a fluidized bed biomass gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Hongming Jiang; Morey, R.V. (Minnesota Univ., St. Paul, MN (United States). Dept. of Agricultural Engineering)

    1992-01-01

    A one-dimensional, steady state, numerical model was developed for a fluidized bed biomass gasifier. The gasifier model consists of a fuel pyrolysis model, an oxidation model, a gasification model and a freeboard model. Given the bed temperature, ambient air flow rate and humidity ratio, fuel moisture content and reactor parameters, the model predicts the fuel feed rate for steady state operation, composition of the producer gas and fuel energy conversion. The gasifier model was validated with experimental results. The effects of major mechanisms (fuel pyrolysis and the chemical and the physical rate processes) were assessed in a sensitivity study of the gasification model. A parametric study was also conducted for the gasifier model. It is concluded that the model can be used for gasifier performance analysis. (author)

  15. Acoustic monitoring of a fluidized bed coating process

    DEFF Research Database (Denmark)

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

    2007-01-01

      The aim of the study was to investigate the potential of acoustic monitoring of a production scale fluidized bed coating process. The correlation between sensor signals and the estimated amount of film applied and percentage release, respectively, were investigated in coating potassium chloride...... (KCl) crystals with ethylcellulose (EC). Vibrations were measured with two different types of accelerometers. Different positions for placing the accelerometers and two different product containers were included in the study. Top spray coating of KCl was chosen as a ‘worst case' scenario from a coating...... point perspective. The acoustic monitoring has the potential of summarising the commonly used means to monitor the coating process. The best partial least squares (PLS) regressions, obtained by the high frequency accelerometer, showed for the release a correlation coefficient of 0.92 and a root mean...

  16. Acoustic fluidization and the scale dependence of impact crater morphology

    Science.gov (United States)

    Melosh, H. J.; Gaffney, E. S.

    1983-01-01

    A phenomenological Bingham plastic model has previously been shown to provide an adequate description of the collapse of impact craters. This paper demonstrates that the Bingham parameters may be derived from a model in which acoustic energy generated during excavation fluidizes the rock debris surrounding the crater. Experimental support for the theoretical flow law is presented. Although the Bingham yield stress cannot be computed without detailed knowledge of the initial acoustic field, the Bingham viscosity is derived from a simple argument which shows that it increases as the 3/2 power of crater diameter, consistent with observation. Crater collapse may occur in material with internal dissipation Q as low as 100, comparable to laboratory observations of dissipation in granular materials. Crater collapse thus does not require that the acoustic field be regenerated during flow.

  17. Conceptual design of a fluidized bed nuclear reactor: Statics, dynamics and safety-related aspects

    OpenAIRE

    Agung, A.

    2007-01-01

    In this thesis a conceptual design of an innovative high temperature reactor based on the fluidization principle (FLUBER) is proposed. The reactor should satisfy the following requirements: (a) modular and low power, (b)) large shutdown margin, (c) able to produce power when the bed of particles expands and stop as soon as the coolant flow is lost, (d) stable from the reactivity point of view, (e) resistant to inherent fluctuations in the fluidization regime, and (f) able to remove post-shutd...

  18. Adaptation of the continuous cold trap system of fluidized-bed to the fluoride volatility process

    International Nuclear Information System (INIS)

    1976-02-01

    A continuous cold trap system consisting of fluidized condenser and stripper has been evaluated with a view to adapt it to the Fluoride Volatility Process in establishing the continuous purification process without radiation decomposition of PuF 6 . Its feasibility is shown by the test with UF 6 -air. Necessary conditions for the cold trap, and performance of the two inch-dia. fluidized bed cold trap system are presented, and also a model of mist formation in the condenser. (auth.)

  19. An Overview of Atmospheric Fluidized Bed Combustion Systems as Applied to Army Scale Central Heat Plants

    Science.gov (United States)

    1992-11-01

    or burned in a separate fluidizcd bed combustor called a carbon burnup cell. Fuel and Sorbent Feed. To achieve high combustion efficier.cy and maximum...AFBC tecnnology is relatively new, calculating the boiler efficiency of fluidized bed boilers is not as well defined as it is for conventional boilers...paragraphs will highlight some options to improve the combustion efficiency. A carbon burnup cell (CBC) uses a separate fluidized bed operated at a much

  20. A Comparison of Granules Produced by High-Shear and Fluidized-Bed Granulation Methods

    OpenAIRE

    Morin, Garett; Briens, Lauren

    2014-01-01

    Placebo granules were manufactured by both wet high-shear and fluidized-bed techniques. The granules were compared based on size, shape, surface morphology, and a variety of different flowability measurements. This comparison showed that granule formation and growth were different, with induction growth for high-shear granulation and steady growth for fluidized-bed granulation. Final granules from high-shear granulation were more spherical and dense compared with the irregular granules from f...

  1. Dehydration Behaviour of Borax Pentahydrate to Anhydrous Borax by Multi-Stage Heating in a Fluidized

    OpenAIRE

    ŞAHİN, Ömer

    2002-01-01

    In order to optimize the anhydrous borax process in a fluidized bed calcinator, it is absolutely necessary to study the dehydration behaviour of borax pentahydrate. It was found that the basic feature of the dehydration of borax pentahydrate to anhydrous borax is concerned with the conditions employed. The bulk density and sodium borate content of the end product were determined to be a function of number of stages of temperature of the dehydration period in the fluidized bed. It...

  2. Fluidized beds with interal screens. II. Study in a cylindrical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jodra, L.G.; Aragon, J.M.; Corella, J.

    1979-10-01

    A fluidized bed reactor with several horizontal tube screens was studied. The number of tubes in a row, the number of rows, and the height to the bottom of the screen were varied. The conversion increase for the chemical reaction of butanol and ammonia was used as a criterion to develop several correlations between screen efficiency and the above variables. The application of the results for the design of fluidized beds with internal screens is also given.

  3. OPTIMIZATION OF DESIGN PARAMETERS OF A STIRLING GENERATOR FOR USE WITH A FLUIDIZED BED COMBUSTOR

    OpenAIRE

    Lombardi, Simone; Bizon, Katarzyna; Marra, Francesco; Continillo, Gaetano

    2012-01-01

    This work investigates the possibility to place the head of a Stirling engine, more specifically the elements of the hot side heat exchanger, in direct contact with the sand of a Fluidized Bed Combustor. This choice is primarily suggested by the heat exchange coefficients between the multiphase fluidized bed medium and the surface of the heat exchanger, much larger than those attained when the heat exchanger is located in the stream of hot flue gases. Moreover, the mechanical action exerted b...

  4. Review of the phenomenon of fluidization and its numerical modelling techniques

    Directory of Open Access Journals (Sweden)

    H Khawaja

    2016-10-01

    Full Text Available The paper introduces the phenomenon of fluidization as a process. Fluidization occurs when a fluid (liquid or gas is pushed upwards through a bed of granular material. This may make the granular material to behave like a liquid and, for example, keep a level meniscus on a tilted container, or make a lighter object float on top and a heavier object sink to the bottom. The behavior of the granular material, when fluidized, depends on the superficial gas velocity, particle size, particle density, and fluid properties resulting in various regimes of fluidization. These regimes are discussed in detail in the paper. This paper also discusses the application of fluidized beds from its early usage in the Winkler coal gasifier to more recent applications for manufacturing of carbon nano-tubes. In addition, Geldart grouping based on the range of particle sizes is discussed. The minimum fluidization condition is defined and it is demonstrated that it may be registered slightly different when particles are being fluidized or de-fluidized. The paper presents discussion on three numerical modelling techniques: the two fluid model, unresolved fluid-particle model and resolved fluid particle model. The two fluid model is often referred to Eulerian-Eulerian method of solution and assumes particles as well as fluid as continuum. The unresolved and resolved fluid-particle models are based on Eulerian-Lagrangian method of solution. The key difference between them is the whether to use a drag correlation or solve the boundary layer around the particles. The paper ends with the discussion on the applicability of these models.

  5. 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.

  6. Sludge combustion in fluidized bed reactors at laboratory scale

    International Nuclear Information System (INIS)

    Chirone, R.; Cammarota, A.

    2001-01-01

    The combustion of a dried sewage sludge in laboratory scale fluidized bed has been studied in Naples by the Istituto di ricerche sulla combustione (Irc) in the framework of a National project named Thermal Process with Energy Recovery to be used in laboratory and pre-pilot scale apparatus. The attention has been focused on emissions of unreacted carbon as elutriated fines, on the emissions of pollutant gases and on the assessment of the inventory of fly- and bottom ashes. The combustion behaviour of sewage sludge has been compared with those of a market available Tyre Derived Fuel (TDF) and a biomass from Mediterranean area (Robinia Pseudoacacia) and with that of a South African bituminous coal. Stationary combustion tests were carried out at 850 0 C by feeding particles in the size range 0-1 mm into a bed of silica sand without any sorbent addition. The fluidized bed combustor has been operated, at a superficial gas velocity of 0.4 m/s and different excesses of air ranging between 14 and 98%. Relatively high combustion efficiency, larger than 98.9% has been obtained in experiments carried out with sewage sludge and excess of air larger than 20%. These values, are comparable with those obtained in previously experimental activity carried out under similar operative conditions with a South Africa Bituminous coal (97-98%). It is larger than those obtained by using a Tyre Derived Fuel (89-90%) and the Robinia Pseudoacacia Biomass (93-93%). The relative importance of carbon fines elutriation, CO emissions and volatile bypassing the bed in determining the loss of combustion efficiency has been evaluated for the different fuels tested [it

  7. Staged fluidized-bed coal combustor for boiler retrofit

    International Nuclear Information System (INIS)

    Rehmat, A.; Dorfman, L.; Shibayama, G.; Waibel, R.

    1991-01-01

    The Advanced Staged Fluidized-Bed Coal Combustion System (ASC) is a novel clean coal technology for either coal-fired repowering of existing boilers or for incremental power generation using combined-cycle gas turbines. This new technology combines staged combustion for gaseous emission control, in-situ sulfur capture, and an ash agglomeration/vitrification process for the agglomeration/vitrification of ash and spent sorbent, thus rendering solid waste environmentally benign. The market for ASC is expected to be for clean coal-fired repowering of generating units up to 250 MW, especially for units where space is limited. The expected tightening of the environmental requirements on leachable solids residue by-products could considerably increase the marketability for ASC. ASC consists of modular low-pressure vessels in which coal is partially combusted and gasified using stacked fluidized-bed processes to produce low-to-medium-Btu, high-temperature gas. This relatively clean fuel gas is used to repower/refuel existing pulverized-coal, natural gas, or oil-fired boilers using bottom firing and reburning techniques. The benefits of ASC coal-fired repowering include the ability to repower boilers without obtaining additional space while meeting the more stringent environmental requirements of the future. Low NO x , SO x , and particulate levels are expected while a nonleachable solid residue with trace metal encapsulation is produced. ASC also minimizes boiler modification and life-extension expenditures. Repowered efficiencies can be restored to the initial operating plant efficiency, and the existing boiler capacity can be increased by 10%. Preliminary cost estimates indicate that ASC will have up to a $250/kW capital cost advantage over existing coal-fired repowering options. 4 figs., 4 tabs

  8. Alkaline Phosphatase: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/alkalinephosphatase.html Alkaline Phosphatase To use the sharing features on this page, please enable JavaScript. What is an Alkaline Phosphatase Test? An alkaline phosphatase (ALP) test measures ...

  9. Temperature and pressure distributions in a 400 kW{sub t} fluidized bed straw gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Erguedenler, A.; Ghaly, A.E.; Hamdullahpur, F. [Technical Univ. of Nova Scotia, Halifax (Canada)

    1993-12-31

    The temperature and pressure distribution characteristics of a 400 kW (thermal) dual-distributor type fluidized bed straw gasifier were investigated. The effects of the bed height, equivalence ratio (actual air-fuel ratio:stoichiometric air-fuel ratio) and fluidization velocity on the temperature and pressure variations in the gasifier were studied. Generally, the bed temperature reached the steady state condition within 15--20 minutes. The average temperature of the dense bed ranged from 649{degrees}C to 875{degrees}C depending on the levels of operating parameters used. The bed temperature increased linearly with increases in the equivalence ratio, higher bed temperatures were observed with lower bed height and no clear trend for the bed temperature with respect to variations in fluidization velocity was observed. The bed height, equivalence ratio and fluidization velocity affected the pressure drop in the fluidized bed gasifier. Increasing the fluidization velocity and/or decreasing the equivalence ratio resulted in higher pressure drops in the dense bed and the freeboard regions whereas increasing the bed height increased the pressure drop only in the dense bed.

  10. Fluidized bed coupled rotary reactor for nanoparticles coating via atomic layer deposition.

    Science.gov (United States)

    Duan, Chen-Long; Liu, Xiao; Shan, Bin; Chen, Rong

    2015-07-01

    A fluidized bed coupled rotary reactor has been designed for coating on nanoparticles (NPs) via atomic layer deposition. It consists of five major parts: reaction chamber, dosing and fluidizing section, pumping section, rotary manipulator components, as well as a double-layer cartridge for the storage of particles. In the deposition procedure, continuous fluidization of particles enlarges and homogenizes the void fraction in the particle bed, while rotation enhances the gas-solid interactions to stabilize fluidization. The particle cartridge presented here enables both the fluidization and rotation acting on the particle bed, demonstrated by the analysis of pressure drop. Moreover, enlarged interstitials and intense gas-solid contact under sufficient fluidizing velocity and proper rotation speed facilitate the precursor delivery throughout the particle bed and consequently provide a fast coating process. The cartridge can ensure precursors flowing through the particle bed exclusively to achieve high utilization without static exposure operation. By optimizing superficial gas velocities and rotation speeds, minimum pulse time for complete coating has been shortened in experiment, and in situ mass spectrometry showed the precursor usage can reach 90%. Inductively coupled plasma-optical emission spectroscopy results suggested a saturated growth of nanoscale Al2O3 films on spherical SiO2 NPs. Finally, the uniformity and composition of the shells were characterized by high angle annular dark field-transmission electron microscopy and energy dispersive X-ray spectroscopy.

  11. From continuum analytical description to discrete numerical modelling of localized fluidization in granular media

    Directory of Open Access Journals (Sweden)

    Puig i Montellà Eduard

    2017-01-01

    Full Text Available We present analytical and numerical results on localized fluidization within a granular layer subjected to a local injection of fluid. As the injection rate increases the three different regimes previously reported in the literature are recovered: homogeneous expansion of the bed, fluidized cavity in which fluidization starts developing above the injection area, and finally the chimney of fluidized grains when the fluidization zone reaches the free surface. The analytical approach is at the continuum scale, based on Darcy’s law and Therzaghi’s effective stress principle. It provides a good description of the phenomenon as long as the porosity of the granular assembly remains relatively homogeneous. The numerical approach is at the particle scale based on the coupled DEM-PFV method. It tackles the more heterogeneous situations which occur at larger injection rates. A direct link is evidenced between the occurrence of the different regimes of fluidization and the injection aperture. Finally, the merging of chimneys in case of two injection points is investigated.

  12. An experimental study of fluidization behavior using flow visualization and image processing

    International Nuclear Information System (INIS)

    Laan, Flavio T. van der; Sefidvash, Farhang; Cornelius, Vanderli

    2000-01-01

    A program of experimental study of fluidization of heavy spherical pellets with water using image processing technique has been started in the Nuclear Engineering Department of the Federal University of Rio Grande do Sul. Fluidization for application in nuclear reactors requires very detailed knowledge of its behavior as the reactivity is closely dependent on the porosity of the fluidized bed. A small modular nuclear reactor concept with suspended core is under study. A modified version of the reactor involves the choice of is to make conical the shape of the reactor core to produce a non-fluctuating bed and consequently guarantee the dynamic stability of the reactor. A 5 mm diameter steel ball are fluidized with water in a conical Plexiglass tube. A pump circulate the water in a loop feeding the room temperature water from the tank into the fluidization system and returning it back to the tank. A controllable valve controls the flow velocity. A high velocity digital CCD camera captures the images of the pellets moving in the fluidized tube. At different flow velocities, the individual pellets can be tracked by processing the sequential frames. A DVT digital tape record stores the images and by acquisition through interface board into a microcomputer. A special program process the data later on. Different algorithm of image treatment determines the velocity fields of the pellets. The behavior of the pellets under different flow velocity and porosity are carefully studied. (author)

  13. 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.

  14. Instability and the formation of bubbles and the plugs in fluidized beds

    Directory of Open Access Journals (Sweden)

    Piotr Schulz

    2004-01-01

    Full Text Available This is an review paper, particulary concentrate on results not many researches by reason that are explain in the text. We consider stability of disperse, two-phase flow (gas-solid particles or liquid-solid particles linear and non-linear. In particular we discuss the result of Anderson, Sundareson and Jackson (1995 [Anderson K., Sundareson S., Jackson R.: Instabilities and the formation of bubbles in fluidized beds. J. Fluid Mech. 303 (1995, 327-366] that for vertical dispersion flow one- and two-dimensional, they attack problem growing disturbances directly by numerical integration of equations of motion from given initial conditions (using computer Cray C-90. In principle, this would allow authors to explore all aspects of dynamical behaviour of fluidized beds. It is interesting mechanism of periodic plug describing by Anderson et al. and attest by other researchers. Second part of paper is more general, dedicate the problem of linear stability of uniformly fluidized state ("fluidized bed". We make the most important stages of calculations (after to Jackson (2000 [Jackson R.: The Dynamics of Fluidized Particles. Cambridge University Press 2000] and demonstrate that the majority (but not all of fluidized beds with parameters having technical importance is unstable, or stable in narrow interval of wave numbers \\(k\\.

  15. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  16. Multisystemic functions of alkaline phosphatases.

    Science.gov (United States)

    Buchet, René; Millán, José Luis; Magne, David

    2013-01-01

    Human and mouse alkaline phosphatases (AP) are encoded by a multigene family expressed ubiquitously in multiple tissues. Gene knockout (KO) findings have helped define some of the precise exocytic functions of individual isozymes in bone, teeth, the central nervous system, and in the gut. For instance, deficiency in tissue-nonspecific alkaline phosphatase (TNAP) in mice (Alpl (-/-) mice) and humans leads to hypophosphatasia (HPP), an inborn error of metabolism characterized by epileptic seizures in the most severe cases, caused by abnormal metabolism of pyridoxal-5'-phosphate (the predominant form of vitamin B6) and by hypomineralization of the skeleton and teeth featuring rickets and early loss of teeth in children or osteomalacia and dental problems in adults caused by accumulation of inorganic pyrophosphate (PPi). Enzyme replacement therapy with mineral-targeting TNAP prevented all the manifestations of HPP in mice, and clinical trials with this protein therapeutic are showing promising results in rescuing life-threatening HPP in infants. Conversely, TNAP induction in the vasculature during generalized arterial calcification of infancy (GACI), type II diabetes, obesity, and aging can cause medial vascular calcification. TNAP inhibitors, discussed extensively in this book, are in development to prevent pathological arterial calcification. The brush border enzyme intestinal alkaline phosphatase (IAP) plays an important role in fatty acid (FA) absorption, in protecting gut barrier function, and in determining the composition of the gut microbiota via its ability to dephosphorylate lipopolysaccharide (LPS). Knockout mice (Akp3 (-/-)) deficient in duodenal-specific IAP (dIAP) become obese, and develop hyperlipidemia and hepatic steatosis when fed a high-fat diet (HFD). These changes are accompanied by upregulation in the jejunal-ileal expression of the Akp6 IAP isozyme (global IAP, or gIAP) and concomitant upregulation of FAT/CD36, a phosphorylated fatty acid

  17. Demonstration of a Full-Scale Fluidized Bed Bioreactor for the Treatment of Perchlorate at Low Concentrations in Groundwater

    Science.gov (United States)

    2009-01-01

    Fluidized Bed Reactor Iron Granulated Activated Carbon Gallons per minute Health & Safety Plan Hydraulic Residence Time Investigation-Derived Waste...FINAL REPORT Demonstration of a Full-Scale Fluidized Bed Bioreactor for the Treatment of Perchlorate at Low Concentrations in Groundwater...area code) 20-01-2009 Final Report March 2006-March 2008; January 2009 DEMONSTRATION OF A FULL-SCALE FLUIDIZED BED BIOREACTOR FOR THE TREATMENT OF

  18. Alkaline pH homeostasis in bacteria: new insights.

    Science.gov (United States)

    Padan, Etana; Bibi, Eitan; Ito, Masahiro; Krulwich, Terry A

    2005-11-30

    The capacity of bacteria to survive and grow at alkaline pH values is of widespread importance in the epidemiology of pathogenic bacteria, in remediation and industrial settings, as well as in marine, plant-associated and extremely alkaline ecological niches. Alkali-tolerance and alkaliphily, in turn, strongly depend upon mechanisms for alkaline pH homeostasis, as shown in pH shift experiments and growth experiments in chemostats at different external pH values. Transcriptome and proteome analyses have recently complemented physiological and genetic studies, revealing numerous adaptations that contribute to alkaline pH homeostasis. These include elevated levels of transporters and enzymes that promote proton capture and retention (e.g., the ATP synthase and monovalent cation/proton antiporters), metabolic changes that lead to increased acid production, and changes in the cell surface layers that contribute to cytoplasmic proton retention. Targeted studies over the past decade have followed up the long-recognized importance of monovalent cations in active pH homeostasis. These studies show the centrality of monovalent cation/proton antiporters in this process while microbial genomics provides information about the constellation of such antiporters in individual strains. A comprehensive phylogenetic analysis of both eukaryotic and prokaryotic genome databases has identified orthologs from bacteria to humans that allow better understanding of the specific functions and physiological roles of the antiporters. Detailed information about the properties of multiple antiporters in individual strains is starting to explain how specific monovalent cation/proton antiporters play dominant roles in alkaline pH homeostasis in cells that have several additional antiporters catalyzing ostensibly similar reactions. New insights into the pH-dependent Na(+)/H(+) antiporter NhaA that plays an important role in Escherichia coli have recently emerged from the determination of the

  19. Heat transfer characteristics in a pulsated fluidized bed in relation to bubble characteristics; Parusu ryudoso no dennetsu tokusei to kiho tokusei tono sokan

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, A.; Hasatani, M. [Nagoya Univ., Nagoya (Japan). Dept. of Energy Engineering and Science; Deguchi, S. [Nagoya Univ., Nagoya (Japan). Center for Integrated Research inn Science and Engineering; Matsuda, H. [Nagoya Univ., Nagoya (Japan). Research Center for Advanced Waste and Emission Management; Mujumdar, A.S. [McGill Univ., Quebec (Canada). Dept. of Chemical Engineering

    2000-11-10

    A pulsated fluidized bed is operated with two sequential duration designated as the on-period with injecting fluidization air, and the off-period without injecting fluidization air. The heat transfer coefficient between a vertically immersed heater and bed in a pulsated fluidized bed is measured under various pulse cycles and fluidized particles. The obtained results are compared with those in a normal fluidized bed with continuous fluidization air injection. The relation between heat transfer coefficient and bubble characteristics, evaluated by using a digital video camera, was investigated. For certain fluidized particles and operated pulse cycles, fluidization of particles and increment of heat transfer coefficient can be obtained under lower mean air velocity based on a pulse cycle duration than minimum fluidization air velocity of the normal fluidized bed. Under the pulse cycles where a static ed is formed in off-period duration, the improved heat transfer rate in contrast with the normal fluidized bed can be measured. This because of the large bubbles formation. As the heat transfer in the pulsated fluidized bed is obstructed with increasing time to keep a static bed due to the excess of-period duration it is indicated that there is an optimum off-period duration based on the heat transfer rate. (author)

  20. Alkaline sorbent injection for mercury control

    Science.gov (United States)

    Madden, Deborah A.; Holmes, Michael J.

    2002-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  1. Alkaline rocks and the occurrence of uranium

    International Nuclear Information System (INIS)

    Hambleton-Jones, B.B.; Toens, P.D.

    1980-10-01

    Many alkaline complexes contain uranium and other minerals in low concentrations and are regarded as constituting valuable potential reserves. Certain complex metallurgical problems, however, remain to be solved. Alkaline rocks occur in a number of forms and environments and it is noted that they are generated during periods of geological quiescence emplaced mainly in stable aseismic areas. Many occur along the extensions of oceanic transform faults beneath the continental crust and the application of this concept to areas not currently known to host alkaline complexes may prove useful in identifying potential target areas for prospecting operations [af

  2. Geochemical features of the Cretaceous alkaline volcanics in the area of Morado hill, Jachal town, San Juan, Argentina

    International Nuclear Information System (INIS)

    Perez, L.

    2010-01-01

    This paper is about the alkaline volcanic rocks that crop out at the Morado hill located in the southern end of the Mogna ranges, which are part of the Eastern border of the pre mountain in the San Juan province, Argentina.The petrography and geochemistry study of the alkaline volcanics has allowed to classify them as tephrite basanite or basanite nephelinite, with strong alkaline chemical affinity, showing a characteristic composition of within plate geochemistry environment. The radimetric analysis, K-Ar data, has shown an average 90 ∓ 8 m.y. age for this rocks, (Cingolani et al. 1984) pointing out the Upper Cretaceous (lower section) stratigraphical position for the suite. The discussion of the results makes conspicuous the relationships of these alkaline rocks with others of the central and northwestern regions of the country that allowed to establish an alkaline petrographic province

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

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, Kim

    2006-10-15

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

  4. Alkalinity in oil field waters - what alkalinity is and how it is measured

    International Nuclear Information System (INIS)

    Kaasa, B.; Oestvold, T.

    1996-01-01

    The alkalinity is an important parameter in the description of pH-behaviour, buffer capacity and scaling potentials in oil field waters. Although the alkalinity is widely used, it seems to be considerable confusion in connection with the concept. It is often used incorrectly and different authors define the concept in different ways. Several different methods for the determination of alkalinity can be found in the literature. This paper discusses the definition of alkalinity and how to use alkalinity in oil field waters to obtain data of importance for scale and pH predictions. There is also shown how a simple titration of oil field waters can give both the alkalinity and the content of organic acids in these waters. It is obvious from these findings that most of the methods used to day may give considerable errors when applied to oil field waters with high contents of organic acids. 8 refs., 8 figs., 5 tabs

  5. Alkaline Electrochemical Capacitor and Electrode Fabrication

    National Research Council Canada - National Science Library

    Finello, D

    1999-01-01

    .... With energy density in excess of 300 mJ/cc and the potential to exceed a power density of 100 W/cc, the alkaline electrochemical capacitor represents a significant advancement in technology for high power energy storage.

  6. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 3. Qualitative Carbohydrate Analysis using Alkaline Potassium Ferricyanide. Sangeeta Pandita Saral Baweja. Classroom Volume 21 Issue 3 March 2016 pp 285-288 ...

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

    Directory of Open Access Journals (Sweden)

    B. Stojanovic

    2009-06-01

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

  8. Toxicity of alkalinity to Hyalella azteca

    Science.gov (United States)

    Lasier, P.J.; Winger, P.V.; Reinert, R.E.

    1997-01-01

    Toxicity testing and chemical analyses of sediment pore water have been suggested for use in sediment quality assessments and sediment toxicity identification evaluations. However, caution should be exercised in interpreting pore-water chemistry and toxicity due to inherent chemical characteristics and confounding relationships. High concentrations of alkalinity, which are typical of sediment pore waters from many regions, have been shown to be toxic to test animals. A series of tests were conducted to assess the significance of elevated alkalinity concentrations to Hyalella azteca, an amphipod commonly used for sediment and pore-water toxicity testing. Toxicity tests with 14-d old and 7-d old animals were conducted in serial dilutions of sodium bicarbonate (NaHCO3) solutions producing alkalinities ranging between 250 to 2000 mg/L as CaCO3. A sodium chloride (NaCl) toxicity test was also conducted to verify that toxicity was due to bicarbonate and not sodium. Alkalinity was toxic at concentrations frequently encountered in sediment pore water. There was also a significant difference in the toxicity of alkalinity between 14-d old and 7-d old animals. The average 96-h LC50 for alkalinity was 1212 mg/L (as CaCO3) for 14-d old animals and 662 mg/L for the younger animals. Sodium was not toxic at levels present in the NaHCO3 toxicity tests. Alkalinity should be routinely measured in pore-water toxicity tests, and interpretation of toxicity should consider alkalinity concentration and test-organism tolerance.

  9. Hybrid Alkaline Cements: Bentonite-Opc Binders

    Directory of Open Access Journals (Sweden)

    Ines Garcia-Lodeiro

    2018-03-01

    Full Text Available Moderately alkaline activators can be used to formulate cementitious binders with a high Supplemetary Cementitious Materials (SCMs and a low portland cement content (hybrid alkaline cements. This study aimed to prepare hybrid alkaline cements containing large percentages of dehydroxylated bentonite (BT and small Portland cement (OPC fractions, with 5% Na2SO4 as a solid alkaline activator. The hydration kinetics of the pastes hydrated in water in the presence and absence of the solid activator were assessed by isothermal conduction calorimetry, whilst the reaction products were characterised with X-Ray Powder Diffraction (XRD and Fourier-transform Infrared Spectroscopy (FTIR. The presence of the alkaline activator hastened OPC and BT/OPC hydration: more heat of hydration was released, favouring greater initial bentonite reactivity. The portlandite forming during cement hydration reacted readily with the Na2SO4, raising medium alkalinity and enhancing bentonite dissolution and with it reaction product precipitation (primarily (N,C-A-S-H-like gels that co-exist with C-S-H- or C-A-S-H-like gels. The presence of sulfate ions favoured the formation of AFm-like phases. Preceding aspects accelerated the hydration reactions, with the formation of more reaction product and matrix densification. As a result, the 28 days Na2SO4 activated systems developed greater mechanical strength than the water-hydrated systems, with the 60% BT/40% OPC blends exhibiting higher compressive strength than the 100% OPC pastes.

  10. 2nd Generation alkaline electrolysis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Yde, L. [Aarhus Univ. Business and Social Science - Centre for Energy Technologies (CET), Aarhus (Denmark); Kjartansdottir, C.K. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Allebrod, F. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark)] [and others

    2013-03-15

    conditions and the degradation mechanism was examined. One of the strong visions for the 2{sup nd} generation electrolyser concept has been to develop a modular system with several standardized components. The following modules have been designed: 1) Electrolyser module; 2) Deoxer Module; 3) Dryer Module; 4) Water Treatment Module; 5) Power supply and Control unit; 6) Rack mount. The developed 2{sup nd} generation rack-mounted alkaline electrolyser system has been installed and demonstrated for 18 month in a college (H2College) with 66 apartments. A number of measurements were performed on the system installed in H2College. No measurements on the overall system efficiency were conducted. However measurement on the stack showed a stack efficiency of 86.5% at a current density of 177mA/cm{sup 2} and a temperature of 74.4 deg. C at the hydrogen outlet. The system is estimated to have run roughly 2000h during the demonstration period. The demonstration of the 2{sup nd} generation alkaline electrolyser is considered a success for several reasons. While not all technical goals were reached, the research and development in the project have resulted in some very good solutions for most of the challenges in high pressure alkaline electrolysis. The concept of a rack mounted electrolyser was proven viable, and all critical aspects of the modularisation have been covered. (LN)

  11. 21 CFR 864.7660 - Leukocyte alkaline phosphatase test.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Leukocyte alkaline phosphatase test. 864.7660... Leukocyte alkaline phosphatase test. (a) Identification. A leukocyte alkaline phosphatase test is a device used to identify the enzyme leukocyte alkaline phosphatase in neutrophilic granulocytes (granular...

  12. Improved electrodes and gas impurity investigations on alkaline electrolysers

    DEFF Research Database (Denmark)

    Reissner, R.; Schiller, G.; Knoeri, T.

    Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved.......Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-06-30

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

  14. Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA

    NARCIS (Netherlands)

    Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

  15. Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA

    NARCIS (Netherlands)

    Pel, M.J.C.; Van Dijken, A.J.H.; Bardoel, B.W.; Seidl, M.F; Van der Ent, S.; Van Strijp, J.A.G.

    2014-01-01

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

  16. Measurement of pH, alkalinity and acidity in ultra-soft waters

    African Journals Online (AJOL)

    drinie

    2001-10-04

    Oct 4, 2001 ... A blend composed of the raw water, sodium chloride (to increase conductivity), and standard bicarbonate (to increase buffering capacity) was titrated with standard strong acid in two pH regions: 6.3 pH < 4.0. In both methods, total alkalinity was determined using the latter set of points, ...

  17. Silica-poor, mafic alkaline lavas from ocean islands and continents

    Indian Academy of Sciences (India)

    Strongly silica-poor (ne-normative), mafic alkaline lavas generally represented by olivine nephelinites, nephelinites, melilitites, and olivine melilitites have erupted at various locations during Earth's history. On the basis of bulk-rock Mg#, high concentrations of Na2O, TiO2, and K2O, and trace element geochemistry, it has ...

  18. Advanced Magnetic Materials Methods and Numerical Models for Fluidization in Microgravity and Hypogravity

    Science.gov (United States)

    Atwater, James; Wheeler, Richard, Jr.; Akse, James; Jovanovic, Goran; Reed, Brian

    2013-01-01

    To support long-duration manned missions in space such as a permanent lunar base, Mars transit, or Mars Surface Mission, improved methods for the treatment of solid wastes, particularly methods that recover valuable resources, are needed. The ability to operate under microgravity and hypogravity conditions is essential to meet this objective. The utilization of magnetic forces to manipulate granular magnetic media has provided the means to treat solid wastes under variable gravity conditions by filtration using a consolidated magnetic media bed followed by thermal processing of the solid wastes in a fluidized bed reactor. Non-uniform magnetic fields will produce a magnetic field gradient in a bed of magnetically susceptible media toward the distributor plate of a fluidized bed reactor. A correctly oriented magnetic field gradient will generate a downward direct force on magnetic media that can substitute for gravitational force in microgravity, or which may augment low levels of gravity, such as on the Moon or Mars. This approach is termed Gradient Magnetically Assisted Fluidization (G-MAFB), in which the magnitude of the force on the fluidized media depends upon the intensity of the magnetic field (H), the intensity of the field gradient (dH/dz), and the magnetic susceptibility of the media. Fluidized beds based on the G-MAFB process can operate in any gravitational environment by tuning the magnetic field appropriately. Magnetic materials and methods have been developed that enable G-MAFB operation under variable gravity conditions.

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

    Science.gov (United States)

    Xing, Liming; Zhao, Zhengsheng

    2012-07-01

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

  20. Flow characteristics in a large jetting fluidized bed with two nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Q.; Liu, Z.; Zhang, J.

    2000-03-01

    Jetting fluidized beds are widely used in a number of industrial processes because of various advantages, such as high rates of heat and mass transfer and chemical reaction. These processes include catalytic and flame processes, combustion and gasification of coal, treatment of wastes, cleaning of dusty gases, coating, and granulation. The penetration depth for millet (1.64 mm) as fluidization particles (Geldart group D) was determined in a large jetting fluidized bed of 0.5 m inner diameter and 8 m height and with two nozzles is precorded by a video camera and analyzed frame by frame. Based on experimental data, an empirical correlation for the penetration depth is proposed. Experimental results indicate that the penetration depth increases with an increase in the jetting velocity. Under the same jet gas velocity, the penetration depth decreases as the nozzle distance decreases. Meanwhile, a simple correlation for jet coalescence height is found. A radial voidage profile in the jetting fluidized bed is investigated using a PC-4 fiber optic concentration probe, the effects of jet gas velocity, and the distance between two nozzles on the radial voidage distribution, and a radial profile with unequal jet gas velocity in a jetting fluidized bed is studied.

  1. Biological reduction of nitrates in wastewaters from nuclear processing using a fluidized-bed bioreactor

    International Nuclear Information System (INIS)

    Pitt, W.W.; Hancher, C.W.; Patton, B.D.

    1981-01-01

    There are a number of nitrate-containing wastewater sources, as concentrated as 30 wt.% NO 3 - and as large as 2000 m 3 /day, in the nuclear fuel cycle. The biological reduction of nitrate in wastewater to gaseous nitrogen, accompanied by the oxidation of a nutrient carbon source to gaseous carbon dioxide, is an ecologically sound and cost-effective method of treating wastewaters containing nitrates. These nitrate-containing wastewater sources can be successfully biologically denitrified to meet discharge standards in the range of 10 to 20 gN(NO 3 - )/m 3 by the use of a fluidized-bed bioreactor. The denitrification bacteria are a mixed culture derived from garden soil; the major strain is Pseudomonas. In the fluidized-bed bioreactor the bacteria are allowed to attach to 0.25- to 0.50-mm-diam coal fluidization particles, which are then fluidized by the upward flow of influent wastewater. Maintaining the bacteria-to-coal weight ratio at approximately 1:10 results in a bioreactor bacteria loading of greater than 20,000 g/m 3 . This paper describes the results of a biodenitrification R and D program based on the use of fluidized bioreactors capable of operating at nitrate levels up to 7000 g/m 3 and achieving denitrification rates as high as 80 g N(NO 3 - ) per day per liter of empty bioreactor volume. 4 figures, 7 tables

  2. Simulation of energetic- and exergetic performance of microwave-assisted fluidized bed drying of soybeans

    International Nuclear Information System (INIS)

    Ranjbaran, M.; Zare, D.

    2013-01-01

    The performance of microwave-assisted fluidized bed drying of soybeans was simulated (using a previously validated mathematical model) and analyzed based on the first- and second law of thermodynamics. The energy and exergy analysis were carried out for several drying conditions. The effects of inlet air temperature, microwave power density, bed thickness and inlet air velocity on the efficiencies and inefficiencies of drying process have been simulated and discussed. Generally, application of microwave energy during fluidized bed drying enhanced the exergy efficiency of drying process. However, the results showed that it was more efficient not to apply microwave energy at the first stage of fluidized bed drying process. The application of higher levels of drying air temperature led in higher exergy efficiencies. The values of mean relative deviations for the predictions of efficiencies and inefficiencies of drying process were less than 14%, compared with those calculated using experimental data. - Highlights: • Introducing a mathematical model to predict the efficiency of microwave-assisted fluidized bed dryers. • Energy and exergy analysis in microwave-assisted fluidized bed drying of grains. • Providing practical recommendations for efficient use of microwave power during drying

  3. Metal adsorbent for alkaline etching aqua solutions of Si wafer

    International Nuclear Information System (INIS)

    Tamada, Masao; Ueki, Yuji; Seko, Noriaki; Takeda, Toshihide; Kawano, Shin-ichi

    2012-01-01

    High performance adsorbent is expected to be synthesized for the removal of Ni and Cu ions from strong alkaline solution used in the surface etching process of Si wafer. Fibrous adsorbent was synthesized by radiation-induce emulsion graft polymerization onto polyethylene nonwoven fabric and subsequent amination. The reaction condition was optimized using 30 L reaction vessel and nonwoven fabric, 0.3 m width and 18 m long. The resulting fibrous adsorbent was evaluated by 48 wt% NaOH and KOH contaminated with Ni and Cu ions, respectively. The concentration levels of Ni and Cu ions was reduced to less than 1 μg/kg (ppb) at the flow rate of 10 h −1 in space velocity. The life of adsorbent was 30 times higher than that of the commercialized resin. This novel adsorbent was commercialized as METOLATE ® since the ability of adsorption is remarkably higher than that of commercial resin used practically in Si wafer processing. - Highlights: ► Adsorbent was synthesized by radiation-induced emulsion graft polymerization. ► Degree of grafting reached 120% at the pre-irradiation of 50 kGy. ► The resulting adsorbent removed Ni and Cu ion in strong alkaline solution. ► Adsorbent was commercialized for filter of Si wafer etchant.

  4. Fast Pyrolysis of Agricultural Wastes in a Fluidized Bed Reactor

    Science.gov (United States)

    Wang, X. H.; Chen, H. P.; Yang, H. P.; Dai, X. M.; Zhang, S. H.

    Solid biomass can be converted into liquid fuel through fast pyrolysis, which is convenient to be stored and transported with potential to be used as a fossil oil substitute. In China, agricultural wastes are the main biomass materials, whose pyrolysis process has not been researched adequately compared to forestry wastes. As the representative agricultural wastes in China, peanut shell and maize stalk were involved in this paper and pine wood sawdust was considered for comparing the different pyrolysis behaviors of agricultural wastes and forestry wastes. Fast pyrolysis experiments were carried out in a bench-scale fluidized-bed reactor. The bio-oil yieldsof peanut shell and maize stalk were obviously lower than that ofpine sawdust. Compared with pine sawdust, the char yields of peanut shell and maize stalk were higher but the heating value of uncondensable gaswas lower. This means that the bio-oil cost will be higher for agricultural wastes if taking the conventional pyrolysis technique. And the characteristic and component analysis resultsof bio-oil revealed that the quality of bio-oil from agricultural wastes, especially maize stalk, was worse than that from pine wood. Therefore, it is important to take some methods to improve the quality of bio-oilfrom agricultural wastes, which should promote the exploitation of Chinese biomass resources through fast pyrolysis in afluidized bed reactor.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

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

  6. Operation of a fluidized-bed bioreactor for denitrification

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  7. 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.

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-09-30

    Although the direct combustion of biomass for energy that applies circulating fluidized bed (CFB) technology is steadily expanding worldwide, only few studies have conducted an environmental assessment of biomass ash thus far. Therefore, this study aims to integrate information on the environmental effects of biomass ash. We investigated the concentration of heavy metal in biomass ash samples (bottom ash, cyclone ash, and filter ash) derived from a CFB boiler that combusted agricultural and forest residues at a biomass power plant (2×12 MW) in China. Ash samples were gathered for the digestion and leaching test. The heavy metal content in the solution and the leachate was studied via an inductively coupled plasma-mass spectrometer and a Malvern Mastersizer 2000 mercury analyzer. Measurements for the chemical composition, particle size distribution, and the surface morphology were carried out. Most of the metals in cyclone ash particles were enriched, whereas Ti and Hg were enriched in filter ash. Residence time contributed most to heavy metal enrichment. Under HJ/T 300 conditions, the heavy metals showed serious leaching characteristics. Under EN 12457-2 conditions, leaching behavior was hardly detected. Copyright © 2012 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

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

  11. Combustion test of refuse derived fuel in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Piao, Guilin; Aono, Shegeru; Yamazaki, Ryohei; Fujima, Yukihisa; Mori, Shigekatsu [Nagoya University, Aichi (Japan); Kondo, Motohiro; Yamaguchi, Masataka [Toyota Motor Corp., Aichi (Japan)

    1999-08-01

    Power generation from Refuse Derived Fuel (RFD) is a promising utilization technology for municipal municipal solid waste. To explain the combustion behaviors of RDF was fed continuously in to a 0.3 x 0.3 m x 2.73 m in height bubbling-type fluidized bed combustor and CO, NO{sub x}, SO{sub x} and HCl concentrations in the flue gas from the combustor were detected by a continuos measurement system. It is found that CO concentration in the flue gas is greatly increased by increasing the RFD feed rate, and CO concentration in the flue gas is greatly decreased by increasing the air ratio because the volatile matters rate is extremely great in combustion of RFD. It is also significantly affected by the secondary air injection and the air distribution ratio from the distributor. HCl concentration in the flue gas is effectively controlled by the calcium compound contained in RDF.HCl concentration is maintained to be less than 60 ppm when the bed temperature is 800 degree C, and the HCl removal ratio by the calcium component is higher than 70% even though under the higher bed temperature than 900 degree C. NO{sub x} concentration was among 50-150 ppm and SO{sub x} concentration is less than 0.5 ppm. (author)

  12. Performance evaluation of an anaerobic fluidized bed reactor with natural zeolite as support material when treating high-strength distillery wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, N. [Renewable Energy Technology Center (CETER), ' ' Jose Antonio Echeverria' ' Polytechnical University, Calle 127 s/n, CP 19390, Apdo. 6028, Habana 6 Marianao, Ciudad de La Habana (Cuba); Montalvo, S. [Department of Chemical Engineering, Santiago de Chile University, Ave. Lib. Bernardo O' Higgins 3363, Santiago de Chile (Chile); Borja, R.; Travieso, L.; Raposo, F. [Instituto de la Grasa (CSIC), Avenida Padre Garcia Tejero 4, 41012 Sevilla (Spain); Guerrero, L. [Department of Chemical, Biotechnological and Environmental Processes, Federico Santa Maria Technical University, Casilla 110-V, Valparaiso (Chile); Sanchez, E.; Colmenarejo, M.F. [Centro de Ciencias Medioambientales (CSIC), C/Serrano, 115-Duplicado, 28006 Madrid (Spain); Cortes, I. [Environment Nacional Center, Chile University, Ave. Larrain 9975, La Reina, Santiago de Chile (Chile)

    2008-11-15

    The performance of two laboratory-scale fluidized bed reactors with natural zeolite as support material when treating high-strength distillery wastewater was assessed. Two sets of experiments were carried out. In the first experimental set, the influences of the organic loading rate (OLR), the fluidization level (FL) and the particle diameter of the natural zeolite (D{sub P}) were evaluated. This experimental set was carried out at an OLR from 2 to 5 g COD (chemical oxygen demand)/l d, at FL 20% and 40% and with D{sub P} in the range of 0.2-0.5 mm (reactor 1) and of 0.5-0.8 mm (reactor 2). It was demonstrated that OLR and FL had a slight influence on COD removal, whereas they had a strong influence on the methane production rate. The COD removal was slightly higher for the highest particle diameter used. The second experimental set was carried out at an OLR from 3 to 20 g COD/l d with 25% of fluidization and D{sub P} in the above-mentioned ranges for reactors 1 and 2. The performance of the two reactors was similar; no significant differences were found. The COD removal efficiency correlated with the OLR based on a straight line. COD removal efficiencies higher than 80% were achieved in both reactors without significant differences. In addition, a straight line equation with a slope of 1.74 d{sup -1} and an intercept on the y-axis equal to zero described satisfactorily the effect of the influent COD on the COD removal rate. It was also observed that both COD removal rate and methane production (Q{sub M}) increased linearly with the OLR, independently of the D{sub P} used. (author)

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

    NARCIS (Netherlands)

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

    2005-01-01

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

  14. Comparison of fibre optical measurements and discrete element simulations for the study of granulation in a spout fluidized bed

    NARCIS (Netherlands)

    Link, J.M.; Godlieb, W.; Tripp, P.; Deen, N.G.; Heinrich, S.; Kuipers, J.A.M.; Schönherr, M.; Peglow, M.

    2009-01-01

    Spout fluidized beds are frequently used for the production of granules or particles through granulation. The products find application in a large variety of applications, for example detergents, fertilizers, pharmaceuticals and food. Spout fluidized beds have a number of advantageous properties,

  15. Comparison of fibre optical measurements and discrete element simulations for the study of granulation in a spout fluidized bed

    NARCIS (Netherlands)

    Link, J.M.; Godlieb, W.; Tripp, P.; Deen, N.G.; Heinrich, S.; Peglow, M.; Kumar, J.; Kuipers, J.A.M.; Schönherr, M.; Mörl, L.

    2007-01-01

    Spout fluidized beds are frequently used for the production of granules or particles through granulation. The products find application in a large variety of applications, for example detergents, fertilizers, pharmaceuticals and food. Spout fluidized beds have a number of advantageous properties,

  16. Comparison of Fibre Optical Measurements and Discrete Element Simulations for the Study of Granulation in a Spout Fluidized Bed

    NARCIS (Netherlands)

    Link, J.M.; Godlieb, W.; Tripp, P.; Deen, N.G.; Heinrich, S.; Kuipers, J.A.M.; Schönherr, M.; Peglow, M.

    2007-01-01

    Spout fluidized beds are frequently used for the production of granules or particles through granulation. The products find application in a large variety of applications, for example detergents, fertilizers, pharmaceuticals and food. Spout fluidized beds have a number of advantageous properties,

  17. Use of Pressure Fluctuations to Determine Online the Regime of Gas-Solids Suspensions from Incipient Fluidization to Transport

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Trnka, Otakar; Svoboda, Karel

    2009-01-01

    Roč. 48, č. 14 (2009), s. 6830-6835 ISSN 0888-5885 R&D Projects: GA AV ČR IAA400720701 Institutional research plan: CEZ:AV0Z40720504 Keywords : fluidized beds * fluidization regimes * pressure fluctuations Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.758, year: 2009

  18. Role of microbial accumulation in biological sulphate reduction using lactate as electron donor in an inversed fluidized bed bioreactor

    NARCIS (Netherlands)

    Cassidy, J.; Frunzo, L.; Lubberding, H.J.; Villa-Gomez, D.K.; Esposito, G.; Keesman, K.J.; Lens, P.N.L.

    2017-01-01

    This study evaluated the impact of substrate accumulation (sulphate and polyhydroxybutyrate (PHB)) on bioprocess control of a sulfate reducing inversed fluidized bed bioreactor. To investigate the impact of substrate accumulation, step feed changes were induced to an inversed fluidized bed

  19. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  20. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  1. Prophylactic treatment with alkaline phosphatase in cardiac surgery induces endogenous alkaline phosphatase release

    NARCIS (Netherlands)

    Kats, Suzanne; Brands, Ruud; Hamad, Mohamed A. Soliman; Seinen, Willem; Schamhorst, Volkher; Wulkan, Raymond W.; Schoenberger, Jacques P.; van Oeveren, Wim

    Introduction: Laboratory and clinical data have implicated endotoxin as an important factor in the inflammatory response to cardiopulmonary bypass. We assessed the effects of the administration of bovine intestinal alkaline phosphatase (bIAP), an endotoxin detoxifier, on alkaline phosphatase levels

  2. The stability of polyaniline in strongly alkaline and acidic aqueous media

    Czech Academy of Sciences Publication Activity Database

    Brožová, Libuše; Holler, Petr; Kovářová, Jana; Stejskal, Jaroslav; Trchová, Miroslava

    2008-01-01

    Roč. 93, č. 3 (2008), s. 592-600 ISSN 0141-3910 R&D Projects: GA MPO FT-TA2/098; GA ČR GA203/08/0686 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * stability * conducting polymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.320, year: 2008

  3. Oxidation of arsenite by molecular oxygen in strong alkaline solution under γ-radiation

    International Nuclear Information System (INIS)

    Burkitbaev, M.M.

    1996-01-01

    The kinetics and mechanism of radiation-stimulated process in 1 mole/1 l of potassium hydroxide have been studied. Radiation chemical yield of (G(As)(Y)) oxygenation grows directly proportionally to oxygen concentration and inversely proportionally to dose rate in proportion 1/2. Mechanism of oxidation, including two chain cycles (long chain cycle - with participation of O - ; O 2 - ; O 3 - radicals and short chain one -with participation of arsenic contenting radicals: As(IV), As(IV)O, As(IV)O 2 ) is proposed. (author)

  4. Study of process parameters for reducing ammonium uranyl carbonate to uranium dioxide in fluidized bed furnace

    International Nuclear Information System (INIS)

    Leitao Junior, C.B.

    1992-01-01

    This work consists of studying the process parameters of AUC (ammonium uranyl carbonate) to U O 2 (uranium dioxide) reduction, with good physical and chemical characteristics, in fluidized bed. Initially, it was performed U O 2 cold fluidization experiments with an acrylic column. Afterward, it was done AUC to U O 2 reduction experiments, in which the process parameters influence in the granulometry, specific surface area, porosity and fluoride amount on the U O 2 powder produced were studied. As a last step, it was done compacting and sintering tests of U O 2 pellets in order to appreciate the U O 2 powder performance, obtained by fluidized bed, in the fuel pellets fabrication. (author)

  5. Bioavailability of sulfadiazine in rabbits using tablets prepared by direct compression and fluidized-bed granulation.

    Science.gov (United States)

    Ritschel, W A; Erni, W

    1977-10-01

    Experimental sulfadiazine tablets prepared by direct compression, using a commercially available direct compression tablet mass, were compared with experimental sulfadiazine tablets prepared by fluidized-bed granulation and commercially available sulfadiazine tablets USP. The values for friability and the time required to release 10 and 50% of the direct compression tablets were between those of the fluidized-bed tablets and the commercial product. With the commercial tablet as a standard, the extent of bioavailability was determined in rabbits; it was slightly higher for both the direct compression and fluidized-bed tablets. A statistically significant difference was found between the direct compression tablets and the standard with respect to the extent of bioavailability and the time of the peak.

  6. 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.

  7. Autocorrelation spectra of an air-fluidized granular system measured by NMR

    Science.gov (United States)

    Lasic, S.; Stepisnik, J.; Mohoric, A.; Sersa, I.; Planinsic, G.

    2006-09-01

    A novel insight into the dynamics of a fluidized granular system is given by a nuclear magnetic resonance method that yields the spin-echo attenuation proportional to the spectrum of the grain positional fluctuation. Measurements of the air-fluidized oil-filled spheres and mustard seeds at different degrees of fluidization and grain volume fractions provide the velocity autocorrelation that differs from the commonly anticipated exponential Enskog decay. An empiric formula, which corresponds to the model of grain caging at collisions with adjacent beads, fits well to the experimental data. Its parameters are the characteristic collision time, the free path between collisions and the cage-breaking rate or the diffusion-like constant, which decreases with increasing grain volume fraction. Mean-squared displacements calculated from the correlation spectrum clearly show transitions from ballistic, through sub-diffusion and into diffusion regimes of grain motion.

  8. Heat transfer and flow characteristics around a finned-tube bank heat exchanger in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Ryosuke [Department of Mechanical Engineering, Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan); Umekawa, Hisashi [Department of Mechanical Engineering, Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan)], E-mail: umekawa@kansai-uac.jp; Ozawa, Mamoru [Department of Mechanical Engineering, Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan)

    2009-06-21

    Principal heat transfer mechanisms in a fluidized bed have been classified into three categories, i.e. solid convection, gas convection and radiation. Among these mechanisms, the solid convection is a dominant mechanism in the bubbling fluidized bed. This solid convection is substantially caused by the bubble movement, thus the visualization of the void fraction distribution becomes a very useful method to understand the characteristics of the fluidized-bed heat exchanger. In this study, the heat transfer coefficient and the void fraction around the heat transfer tube with annuler fin were measured. For the quantitative measurement of the void fraction, neutron radiography and image processing technique were employed. Owing to the existence of the annuler fin, the restriction of the particle movements was put. This restriction suppressed the disturbance caused by tubes, and the influence of the tube arrangement on the flow and heat transfer characteristics could be clearly expressed.

  9. Development of a pressurized fluidized-bed biomass gsifier to produce substitute fuels

    Science.gov (United States)

    Babu, S. P.; Onischak, M.; Kosowski, G.

    The Institute of Gas technology (IGT) is conducting a program to convert forest and crop residues to substitute fuel in a pressurized fluidized-bed biomass gasifier. The process is designed for operation at pressures up to 2.17 MPa (315 psia) and temperatures up to 1255 K (1800 F). Various goals for synthesis or fuel gas processes are being pursued to develop an efficient process. Some of these goals are to maximize the throughput, the amount, and the quality of the gas, while minimizing both the amount of the feedstock preparation needed and the formation of condensible compounds that require by-product disposal and process wastewater treatment. The process development results obtained from fluidization biomass devolatilization, and char gasification studies were used to design a 30/5-cm (12-inch) ID adiabatic fluidized-bed gasification process development unit (PDU), capable of handling up to 455 kg (1000 lb) of biomass per hour.

  10. Co-combustion of risk husk with coal in a fluidized bed

    International Nuclear Information System (INIS)

    Ghani, A.K.; Alias, A.B.; Savory, R.M.; Cliffe, K.R.

    2006-01-01

    Power generation from biomass is an attractive technology which utilizes agricultural residue waste. In order to explain the behavior of biomass-fired fluidized bed incinerator, biomass sources from agricultural residues (rice husk) was co-fired with coal in a 0.15 m diameter and 2.3 m high fluidized bed combustor. The combustion efficiency and CO emissions were studied and compared with those for pure coal combustion. Biomass waste with up to 70% mass fraction can be co-combusted in a fluidized bed combustor designed for coal combustion with a maximum drop of efficiency of 20% depending upon excess air levels. CO levels fluctuated between 200-700 ppm were observed when coal is added. It is evident from this research that efficient co-firing of rice husk with coal can be achieved with minimum modification of existing coal-fired boilers. (Author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-01-01

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

  12. Heat transfer and flow characteristics around a finned-tube bank heat exchanger in fluidized bed

    International Nuclear Information System (INIS)

    Honda, Ryosuke; Umekawa, Hisashi; Ozawa, Mamoru

    2009-01-01

    Principal heat transfer mechanisms in a fluidized bed have been classified into three categories, i.e. solid convection, gas convection and radiation. Among these mechanisms, the solid convection is a dominant mechanism in the bubbling fluidized bed. This solid convection is substantially caused by the bubble movement, thus the visualization of the void fraction distribution becomes a very useful method to understand the characteristics of the fluidized-bed heat exchanger. In this study, the heat transfer coefficient and the void fraction around the heat transfer tube with annuler fin were measured. For the quantitative measurement of the void fraction, neutron radiography and image processing technique were employed. Owing to the existence of the annuler fin, the restriction of the particle movements was put. This restriction suppressed the disturbance caused by tubes, and the influence of the tube arrangement on the flow and heat transfer characteristics could be clearly expressed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

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

  14. 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

    samples,agglomeration could be attributed to viscous silicate melts formed from reaction of inorganic alkalineand alkali earth species with silica from the bed particles. A mathematical model that addresses the defluidization behavior of alkali-rich samples was developed based on the experiments performed...... 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...... in the bench-scale fluidized bed reactor as well as on results from literature. The model was then used topredict the de-fluidization behavior of alkali-rich bed material in a large-scale LTCFB gasifier....

  15. An alternative method for float-sink analysis of fine coal samples using water fluidization

    Energy Technology Data Exchange (ETDEWEB)

    A.M. Callen; S.J. Pratten; B.D. Belcher; N. Lambert; K.P. Galvin [University of Newcastle, Callaghan, NSW (Australia). School of Engineering

    2002-12-01

    The study reported is concerned with the development of a new method, based on water fluidization, for obtaining washability information for -4 +0.045 mm coal samples, with a view to providing a rapid, accurate, and safe alternative to the current laboratory method of float-sink testing. Previously, Galvin and Pratten have reported the technique of utilizing the density segregation effect of a narrow size range of particles in a fluidized bed to determine washability data. Here, the evaluation of the new method by determining the yield-ash data of a number of different Australian coals has demonstrated the robustness and accuracy of the water fluidization method. 7 refs., 9 figs., 1 app.

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

    Directory of Open Access Journals (Sweden)

    C. Alberto S. Felipe

    2004-09-01

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

  17. Fluid dynamic study of a new type of solid-gas contactor: the fluidized/fixed or fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Corella, J.; Bilbao, R.

    1982-10-01

    A fluid dynamic study of a new type of solid-gas contactor has been realized. This contactor consists of a fluidized bed with a considerable enlargement of the cross section of its upper zone. This enlargement of section results in a reduction of the gas velocity in the upper zone, with a subsequent bubbling diminution. Experiments have been performed varying the scale of the contactor, its geometry, the relation between the cross sections of the upper and lower zones of the contactor, the solid height in the upper zone, and the density and size of the solid. The study has been centered on the contactor behavior with variation of the inlet gas velocity, on the bubble size distribution along the contactor, on the determination of the gas pressure drop in the whole contactor and in each zone of the bed, and on the calculation of the gas velocities modifying the state of the contactor (u /SUB r/, u /SUB c/, u /SUB mf/).

  18. Considerations on valorization of biomass origin materials in co-combustion with coal in fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    I. Gulyurtlu; P. Abelha; H. Lopes; A. Crujeira; I. Cabrita [DEECA-INETI, Lisbon (Portugal)

    2007-07-01

    Co-combustion of biomass materials with coal is currently gaining increasing importance, in order to meet the targets on greenhouse gas emissions, defined in the Kyoto protocol. Co-firing of coal with biomass materials could be the short-term solution in reducing CO{sub 2} emissions from power stations. The work undertaken studied co-firing of meat and bone meal (MBM), olive cake and straw pellets with bituminous coals from Colombia (CC) and Poland (PC), which are commonly used in European power stations. The co-combustion studies were carried out on the pilot fluidized bed installation of INETI. Gaseous pollutants and solid concentration in flue gases and ashes from different locations were monitored. Results obtained indicate that the co-feeding of biomass materials did not present any problem and ensured stable combustion conditions and high efficiency. However, for temperatures above 800{sup o}C, bed agglomeration could be observed for all biomass species studied. Most of the combustion of biomass material, contrary to that of coal, was observed to take place in the riser where the temperature was as high as 150-250{sup o}C above that of the bed. SO{sub 2} and NOx levels were found to be lower. The emissions of dioxins could be considerable with fuels with high Cl as is the case with straw. However, mixing of fuels with high S content could lead to a strong reduction in dioxin emissions. Ashes produced from biomass combustion may be considered for further reutilization or landfilling. Other options depend on their characteristics, chemical composition and leaching behaviour. This was evaluated in this study.

  19. Mercury emissions during cofiring of sub-bituminous coal and biomass (chicken waste, wood, coffee residue, and tobacco stalk) in a laboratory-scale fluidized bed combustor.

    Science.gov (United States)

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

    2008-12-15

    Four types of biomass (chicken waste, wood pellets, coffee residue, and tobacco stalks) were cofired at 30 wt % with a U.S. sub-bituminous coal (Powder River Basin Coal) in a laboratory-scale fluidized bed combustor. A cyclone, followed by a quartz filter, was used for fly ash removal during tests. The temperatures of the cyclone and filter were controlled at 250 and 150 degrees C, respectively. Mercury speciation and emissions during cofiring were investigated using a semicontinuous mercury monitor, which was certified using ASTM standard Ontario Hydra Method. Test results indicated mercury emissions were strongly correlative to the gaseous chlorine concentrations, but not necessarily correlative to the chlorine contents in cofiring fuels. Mercury emissions could be reduced by 35% during firing of sub-bituminous coal using only a quartz filter. Cofiring high-chlorine fuel, such as chicken waste (Cl = 22340 wppm), could largely reduce mercury emissions by over 80%. When low-chlorine biomass, such as wood pellets (Cl = 132 wppm) and coffee residue (Cl = 134 wppm), is cofired, mercury emissions could only be reduced by about 50%. Cofiring tobacco stalks with higher chlorine content (Cl = 4237 wppm) did not significantly reduce mercury emissions. This was also true when limestone was added while cofiring coal and chicken waste because the gaseous chlorine was reduced in the freeboard of the fluidized bed combustor, where the temperature was generally below 650 degrees C without addition of the secondary air. Gaseous speciated mercury in flue gas after a quartz filter indicated the occurrence of about 50% of total gaseous mercury to be the elemental mercury for cofiring chicken waste, but occurrence of above 90% of the elemental mercury for all other cases. Both the higher content of alkali metal oxides or alkali earth metal oxides in tested biomass and the occurrence of temperatures lower than 650 degrees C in the upper part of the fluidized bed combustor seemed to be

  20. CFD-DEM and Experimental Study of Bubbling in a Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Hassan A. Khawaja

    2015-12-01

    Full Text Available In this study, phenomenon of bubbling is investigated using CFD-DEM and experiments. A CFD-DEM simulation is setup to model the fluidized beds of different sizes. Geldart D particles of 1.2 mm diameter and 1000 Kg/m3 density are modelled. Study revealed different types of fluidization regimes as stated in the literature. An experimental setup is built to obtain the results for the comparison. Comparison revealed that results obtained from both methodologies; CFD-DEM and experiments are in reasonable agreement.

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

    Science.gov (United States)

    Guo, Feihong; Zhong, Zhaoping

    2017-12-01

    This work presents studies on the combustion of Composite Biomass Pellets (CBP S ) in fluidized bed using bauxite particles as the bed material. Prior to the combustion experiment, cold-flow characterization and thermogravimetric analysis are performed to investigate the effect of air velocity and combustion mechanism of CBP S . The cold-state test shows that CBPs and bauxite particles fluidize well in the fluidized bed. However, because of the presence of large CBPs, optimization of the fluidization velocity is rather challenging. CBPs can gather at the bottom of the fluidized bed at lower gas velocities. On the contrary, when the velocity is too high, they accumulate in the upper section of the fluidized bed. The suitable fluidization velocity for the system in this study was found to be between 1.5-2.0m/s. At the same time, it is found that the critical fluidization velocity and the pressure fluctuation of the two-component system increase with the increase of CBPs mass concentration. The thermogravimetric experiment verifies that the combustion of CBPs is a first-order reaction, and it is divided into three stages: (i) dehydration, (ii) release and combustion of the volatile and (iii) the coke combustion. The combustion of CBPs is mainly based on the stage of volatile combustion, and its activation energy is greater than that of char combustion. During the combustion test, CBP S are burned at a 10kg/h feed rate, while the excess air is varied from 25% to 100%. Temperatures of the bed and flue gas concentrations (O 2 , CO, SO 2 and NO) are recorded. CBPs can be burnt stably, and the temperature of dense phase is maintained at 765-780°C. With the increase of the air velocity, the main combustion region has a tendency to move up. While the combustion is stable, O 2 and CO 2 concentrations are maintained at about 7%, and 12%, respectively. The concentration of SO 2 in the flue gas after the initial stage of combustion is nearly zero. Furthermore, NO concentration

  2. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-12-01

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

  4. Fluidized bed combustion of low-grade coal and wastes: Research and development

    Energy Technology Data Exchange (ETDEWEB)

    Borodulya, V.A.; Dikalenko, V.I.; Palchonok, G.I.; Vinogradov, L.M. [Academy of Sciences of Belarus, Minsk (Belarus). A.V. Luikov Heat and Mass Transfer Inst.; Dobkin, S.M.; Telegin, E.M. [Special Design Office, Brest (Belarus)

    1994-12-31

    Experimental studies were carried out to investigate devolatilization of fuel as single spherical particles of wood, hydrolytic lignin, leather sewage sludge and Belarussian brown coals in a fluidized bed of sand. It is found that the devolatilization process depends on moisture and ash contents in fuel and on the external heat and mass transfer rate. The char combustion occurs largely in the intermediate region. Kinetic parameters of the devolatilization and char combustion are obtained. A low-capacity fluidized bed boiler suitable for combustion of coal and different wastes is described.

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

    Science.gov (United States)

    Cheng, George Shu-Xing; Mulkey, Steven L

    2014-12-16

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

  6. Fluidization Characteristics of Medium-High-Consistency Pulp Fiber Suspensions with an Impeller

    Directory of Open Access Journals (Sweden)

    Ye Daoxing

    2016-01-01

    Full Text Available When the mass concentration exceeds 7%, pulp suspensions stop flowing and act like a solid. To investigate the fluidization characteristics of medium-high-consistency pulp suspensions and achieve pulp fluidization and pumping, experiments were carried out with waste tissue pulp and unbleached kraft pulp. The objectives of this paper were to study the rheology of medium-high-consistency pulp and to determine accurate parameters for the physical Herschel-Bulkley model. To validate this model, computational fluid dynamics (CFD results were compared to experimental data. The simulation values were very similar and were in agreement with experimental results.

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

    DEFF Research Database (Denmark)

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

    2004-01-01

    In the preformulation stage, there is a special need to determine the process behavior of materials with smaller amounts of samples. The purpose of this study was to assemble a novel automated multichamber microscale fluid bed module with a process air control unit for the characterization...... of fluidization behavior in variable conditions. The results were evaluated on the basis of two common computational methods, the minimum fluidization velocity, and the Geldart classification. The materials studied were different particle sizes of glass beads, microcrystalline cellulose, and silicified......, the utilization of the computational predictions was restricted. The presented setup is a novel approach for studying process behavior with only a few grams of materials....

  8. Agglomeration mechanism in biomass fluidized bed combustion – Reaction between potassium carbonate and silica sand

    DEFF Research Database (Denmark)

    Anicic, Bozidar; Lin, Weigang; Dam-Johansen, Kim

    2018-01-01

    Agglomeration is one of the operational problems in fluidized bed combustion of biomass, which is caused by interaction between bed materials (e.g. silica sand) and the biomass ash with a high content of potassium species. However, the contribution of different potassium species to agglomeration......CO3 and silica sand, forming a thin product layer. The layer acted as a reactive media further reacting with K2CO3 and silica sand. The results provide a basis for understanding of potassium induced agglomeration process in fluidized bed biomass combustion....

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

    CERN Document Server

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

    2012-01-01

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

  10. Conversion of solid carbonaceous fuels in a fluidized bed fuel cell

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

  11. Strong Arcwise Connectedness

    OpenAIRE

    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana

    2012-01-01

    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  12. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  13. Assessing ocean alkalinity for carbon sequestration

    Science.gov (United States)

    Renforth, Phil; Henderson, Gideon

    2017-09-01

    Over the coming century humanity may need to find reservoirs to store several trillions of tons of carbon dioxide (CO2) emitted from fossil fuel combustion, which would otherwise cause dangerous climate change if it were left in the atmosphere. Carbon storage in the ocean as bicarbonate ions (by increasing ocean alkalinity) has received very little attention. Yet recent work suggests sufficient capacity to sequester copious quantities of CO2. It may be possible to sequester hundreds of billions to trillions of tons of C without surpassing postindustrial average carbonate saturation states in the surface ocean. When globally distributed, the impact of elevated alkalinity is potentially small and may help ameliorate the effects of ocean acidification. However, the local impact around addition sites may be more acute but is specific to the mineral and technology. The alkalinity of the ocean increases naturally because of rock weathering in which >1.5 mol of carbon are removed from the atmosphere for every mole of magnesium or calcium dissolved from silicate minerals (e.g., wollastonite, olivine, and anorthite) and 0.5 mol for carbonate minerals (e.g., calcite and dolomite). These processes are responsible for naturally sequestering 0.5 billion tons of CO2 per year. Alkalinity is reduced in the ocean through carbonate mineral precipitation, which is almost exclusively formed from biological activity. Most of the previous work on the biological response to changes in carbonate chemistry have focused on acidifying conditions. More research is required to understand carbonate precipitation at elevated alkalinity to constrain the longevity of carbon storage. A range of technologies have been proposed to increase ocean alkalinity (accelerated weathering of limestone, enhanced weathering, electrochemical promoted weathering, and ocean liming), the cost of which may be comparable to alternative carbon sequestration proposals (e.g., $20-100 tCO2-1). There are still many

  14. Pluto: Fluidized Transport of Tholins by Heating of the Subsurface

    Science.gov (United States)

    Cruikshank, Dale P.; Spohrer, Steven; Grundy, William M.; Moore, Jeffrey M.; Umurhan, Orkan M.; White, Oliver L.; Beyer, Ross A.; Dalle Ore, Cristina M.; Stern, S. A.; Young, Leslie; hide

    2017-01-01

    New Horizons images of Pluto show evidence of the transport of the colored non-ice component across the surface, with substantial accumulations in some areas of low elevation. The non-ice component is presumed to be tholin produced in the atmosphere as a precipitating aerosol, in the surface ices by photolysis or radiolysis, or both. We model the surface layer of N2 ice with varying amounts of incorporated tholin particles to explore the heating within the ice that occurs by the solid-state greenhouse effect. We find that in plausible models of the contaminated N2 surface ice the triple point temperature (63.15K) is reached at a depth of approximately less than 1m. At that depth the confining pressure of the ice column is much less than the triple point pressure (12.52 kPa), so N2 should convert to the gas phase, exerting pressure on the overburden. When the gas pressure exceeds the strength of the confining ice, a breakout on the surface will occur, fluidizing fragments of ice and its contaminants that are then free to flow downhill, rafted on entrained gas, similar in some ways to the pyroclastic volcanic phenomenon known as nuée ardente. The digital elevation map of Pluto made from stereo images shows some surface regions that may have been stripped of the N2 layer, exposing H2O ice (presumed to be bedrock) below, with a corresponding accumulation of dark material that was that was the previously entrained particulate tholin. Accumulations of tholin are found associated with some of the fossae, and some cover preexisting topography to depths of up to a few hundred meters.

  15. Database implementation to fluidized cracking catalytic-FCC process

    International Nuclear Information System (INIS)

    Santana, Antonio Otavio de; Dantas, Carlos Costa; Santos, Valdemir A. dos

    2009-01-01

    A process of Fluidized Cracking Catalytic (FCC) was developed by our research group. A cold model FCC unit, in laboratory scale, was used for obtaining of the data relative to the following parameters: air flow, system pressure, riser inlet pressure, rise outlet pressure, pressure drop in the riser, motor speed of catalyst injection and density. The measured of the density is made by gamma ray transmission. For the fact of the process of FCC not to have a database until then, the present work supplied this deficiency with the implementation of a database in connection with the Matlab software. The data from the FCC unit (laboratory model) are obtained as spreadsheet of the MS-Excel software. These spreadsheets were treated before importing them as database tables. The application of the process of normalization of database and the analysis done with the MS-Access in these spreadsheets treated revealed the need of an only relation (table) for to represent the database. The Database Manager System (DBMS) chosen has been the MS-Access by to satisfy our flow of data. The next step was the creation of the database, being built the table of data, the action query, selection query and the macro for to import data from the unit FCC in study. Also an interface between the application 'Database Toolbox' (Matlab2008a) and the database was created. This was obtained through the drivers ODBC (Open Data Base Connectivity). This interface allows the manipulation of the database by the users operating in the Matlab. (author)

  16. Pressurized fluidized-bed hydroretorting of Eastern oil shales

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

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

  17. A unified ion chromatographic system for the determination of acidity and alkalinity.

    Science.gov (United States)

    Hu, W; Hasebe, K; Iles, A; Tanaka, K

    2001-12-01

    A unified ion chromatographic (IC) system was developed for the determination of acidity or alkalinity. Separation column used was a reversed-phase ODS packed column, which had been modified by saturating it with lithium dodecylsulfate. A slightly acidified LiCl (50 mM LiCl and 0.05 mM H2SO4) aqueous solution was used as the eluent. By conditioning the separation column in this way, both H+ and Li+ ions became bound to the stationary phase. Dodecylsulfate groups with Li+ counterions acted as cation-exchange sites for the separation of hydrogen ions (free acidity determination). The remaining dodecylsulfate groups, with H+ counterions acted as a titrant, which reacted with basic species (total alkalinity determination). The acidity or alkalinity of each sample was measured according to the change in conductance from the eluent baseline level. A positive peak was observed from those samples with a free acidity greater than their total alkalinity, due to the separation/elution of free H+ ions. A negative peak was observed from those samples with a free acidity less than their total alkalinity. This was due to an equivalent amount of eluent H+ ions being re-supplied to the stationary phase while the "solid titrant" consumed by the acid-base reaction was regenerated. The retention time for the peak corresponding to the acidity or alkalinity was governed by the retention time for H+ ions in this IC system. Samples with a free acidity greater than 2.25 microM (tested by determination of H+ ions in pure water in equilibrium with atmospheric CO2) could be analyzed by this method. A very similar detection level was obtained for alkalinity (tested by analyzing standard aqueous NaHCO3 solutions). Aqueous solutions of some strong-acid/strong-base inorganic salts were found to be slightly alkaline. This was measured as a percentage, relative to an NaHCO3 solution at the same concentration. Solutions of NaClO4, Na2SO4, NaI, NaNO3, and NaCl, gave comparative alkalinity values of 8

  18. Catalytic oxidation of soot over alkaline niobates

    International Nuclear Information System (INIS)

    Pecchi, G.; Cabrera, B.; Buljan, A.; Delgado, E.J.; Gordon, A.L.; Jimenez, R.

    2013-01-01

    Highlights: ► No previous reported studies about alkaline niobates as catalysts for soot oxidation. ► NaNbO 3 and KNbO 3 perovskite-type oxides show lower activation energy than other lanthanoid perovskite-type oxides. ► The alkaline niobate does not show deactivation by metal loss. - Abstract: The lack of studies in the current literature about the assessment of alkaline niobates as catalysts for soot oxidation has motivated this research. In this study, the synthesis, characterization and assessment of alkaline metal niobates as catalysts for soot combustion are reported. The solids MNbO 3 (M = Li, Na, K, Rb) are synthesized by a citrate method, calcined at 450 °C, 550 °C, 650 °C, 750 °C, and characterized by AAS, N 2 adsorption, XRD, O 2 -TPD, FTIR and SEM. All the alkaline niobates show catalytic activity for soot combustion, and the activity depends basically on the nature of the alkaline metal and the calcination temperature. The highest catalytic activity, expressed as the temperature at which combustion of carbon black occurs at the maximum rate, is shown by KNbO 3 calcined at 650 °C. At this calcination temperature, the catalytic activity follows an order dependent on the atomic number, namely: KNbO 3 > NaNbO 3 > LiNbO 3 . The RbNbO 3 solid do not follow this trend presumably due to the perovskite structure was not reached. The highest catalytic activity shown by of KNbO 3 , despite the lower apparent activation energy of NaNbO 3 , stress the importance of the metal nature and suggests the hypothesis that K + ions are the active sites for soot combustion. It must be pointed out that alkaline niobate subjected to consecutive soot combustion cycles does not show deactivation by metal loss, due to the stabilization of the alkaline metal inside the perovskite structure.

  19. Separation of pig bone alkaline phosphatase activities.

    Science.gov (United States)

    Leunis, J C; Vancraeynest, T; Brauman, J

    1977-01-01

    A simple method for the separation of alkaline phosphatase and pyrophosphatase activities of pig bone ribs is described. Using anionic exchange chromatography (DEAE-cellulose) and affinity chromatography on Concanavalin A sepharose (Con A) eluted by a step pH gradient and Na4P2O7, several activities were obtained. A pyrophosphatase containing very little alkaline phosphatase activity was isolated from Con A sepharose by elution with pyrophosphatase. Our data are consistent, with the hypothesis that cortical alcaline phosphatase and pyrophosphatase activities are not due to a single enzyme protein. The method was used on whole bone, on bone marrow and on cortical bone.

  20. Alkaline earth filled nickel skutterudite antimonide thermoelectrics

    Science.gov (United States)

    Singh, David Joseph

    2013-07-16

    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  1. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Science.gov (United States)

    Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka

    2014-01-01

    The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes, or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70% molar yield toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

  2. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Directory of Open Access Journals (Sweden)

    Eero eSalminen

    2014-02-01

    Full Text Available The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat benzalkonium [ADBA] (alkyldimethylbenzylammonium was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs. Typically, a SILCA contains metal nanoparticles, enzymes or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC. The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70 % molar yield towards citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

  3. Eichrom's ABEC trademark resins: Alkaline radioactive waste treatment, radiopharmaceutical, and potential hydrometallurgical applications

    International Nuclear Information System (INIS)

    Bond, A.H.; Gula, M.J.; Chang, F.; Rogers, R.D.

    1997-01-01

    Eichrom's ABEC trademark resins selectivity extract certain anions from high ionic strength acidic, neutral, or strongly alkaline media, and solute stripping can be accomplished by eluting with water. ABEC resins are stable to pH extreme and radiolysis and operate in high ionic strength and/or alkaline solutions where anion-exchange is often ineffective. Potential applications of the ABEC materials include heavy metal and ReO 4 - separations in hydrometallurgy and purification of perrhenate iodide, and iodate in radiopharmaceutical production. Separation of 99m TcO 4 - from its 99 MoO 4 2- parent and stripping with water or physiological saline solution have been demonstrated for radiopharmaceutical applications. Removal of 99 TcO 4 - and 129 I - from alkaline tank wastes has also been successfully demonstrated. The authors will discuss the scale-up studies, process-scale testing, and market development of this new extraction material

  4. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  5. Investigation of flow mechanisms in conical models of fluidized beds and transfer of the results to high-temperature-coating beds. A study on the coating of nuclear fuel particles in fluidized beds

    International Nuclear Information System (INIS)

    Kalthoff, B.; Gyarmati, E.; Nickel, H.

    The different states of movement of the fluid-solid particle system as occurring in coating of nuclear particle fuel in conical fluidized beds determine the transfer of momentum, heat and mass in the fluidized bed. To know the flow characteristics, therefore, is essential for the understanding of the complex processes which take place during coating. As experimental studies in actual coaters initially were impossible due to the high temperature levels of up to 2000 0 C, information on characteristic behavior of the fluidized bed was obtained from geometrically similar model beds. Based on principles in the mechanics of similarity the fluid-solid particle system was selected. Hence, results obtained in model tests could be correlated to hot fluidized beds by means of a dimensionless characteristic number describing the fluid-solid system. A second combination of characteristic numbers allows the characterization of the three states of a fluidizing regime, i.e., spouting, bubbling, and slugging. For examining the model test results in hot beds, a measuring device was developed applicable to both cold model beds and actual fluidized bed coaters; pressure oscillations originating in the beds could be made visible by means of electronics and their frequency measured. Coating experiments with different batches and at different temperature levels rendered this frequency to decrease with increase in bed height. Thus the frequency is an important index for the momentary state of fluidization of the fluid-solid particle system. (U.S.)

  6. Implementation of an artificial neural network as a PAT tool for the prediction of temperature distribution within a pharmaceutical fluidized bed granulator.

    Science.gov (United States)

    Korteby, Yasmine; Mahdi, Yassine; Azizou, Amel; Daoud, Kamel; Regdon, Géza

    2016-06-10

    In this study, a novel in-line measurement technique of the air temperature distribution during a granulation process using a conical fluidized bed was designed and built for the purpose of measuring the temperature under the Process Analytical Technology (PAT) and introduced to predict the establishment of temperature profiles. Three sets of thermocouples were used, placed at different positions covering the whole operating range, connected to data acquisition measurement hardware, allowing an in-line acquisition and recording of temperatures every second. The measurements throughout the fluidized bed were performed in a steady state by spraying a solution of PVP onto a lactose monohydrate powder bed in order to make predictions of the temperature distribution and the hydrodynamics of the bed during the granulation process using Artificial Neural Networks (ANNs) and to establish the different temperature profiles for different process conditions through the precise predicted information by the constructed, trained, validated and tested neural network. The model's testing results showed a strong prediction capacity of the effects of process variables. Indeed, the predicted temperature values obtained with the ANN model were in good agreement with the values measured with in-line reference method and hence the method can have an application as a predictive control tool. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Determination of Acidity and Alkalinity of Food Materials

    OpenAIRE

    三浦,芳助; 福永,祐子; 瀧川,裕里子; 津田,真美; 渡辺,陽子; 瀨山,一正

    2006-01-01

    The acidity and alkalinity of food materials in various menus was determined to clarify the influence of food on physiological functions. Menus mainly containing alkaline food materials (alkaline menu) and acid ones (acid menu) were compared. Determination of acidity and alkalinity was performed for each food material in the alkaline menu and acid menu, and acidity and alkalinity of one meal and a day's one were estimated. 1. Most of food materials in acid menu were assessed to be...

  8. Production optimization of a heat-tolerant alkaline pectinase from Bacillus subtilis ZGL14 and its purification and characterization.

    Science.gov (United States)

    Yu, Ping; Zhang, Yishu; Gu, Donglu

    2017-09-03

    Alkaline pectinase has important applications in the pretreatment of waste water from food processing and in both the fabric and paper industries. In this study, a 2-level factorial design was used to screen significant factors that affect the activity of alkaline pectinase, and the response surface methodology (RSM) with a Box-Behnken design (BBD) was used to optimize their concentrations. Starch, peptone, KH 2 PO 4 and K 2 HPO 4 ·3H 2 O were found to significantly affect the activity of alkaline pectinase. Their optimal concentrations were as follows: 4.68% starch, 1.6% peptone, 0.26% KH 2 PO 4 and 0.68% K 2 HPO 4 ·3H 2 O. Under the above conditions, the activity of alkaline pectinase was significantly improved to 734.11 U/mL. Alkaline pectinase was purified to homogeneity with a recovery rate of 9.6% and a specific activity of 52372.52 U/mg. Its optimal temperature and pH were 50°C and 8.6, respectively. The purified enzyme showed strong thermo-stability and good alkali resistance. In addition, the activity of alkaline pectinase was improved in the presence of Mg 2+ . Cu 2+ , Mn 2+ , and Co 2+ significantly inhibited its activity. This study provides an important basis for the future development and use of a heat-tolerant alkaline pectinase from B. subtilis ZGL14.

  9. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?

    Directory of Open Access Journals (Sweden)

    Gerry K. Schwalfenberg

    2012-01-01

    Full Text Available This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine.

  10. CFD Analysis to Calculate the Optimal Air Velocity in Drying Green Tea Process Using Fluidized Bed Dryer

    Science.gov (United States)

    Yohana, Eflita; Nugraha, Afif Prasetya; Diana, Ade Eva; Mahawan, Ilham; Nugroho, Sri

    2018-02-01

    Tea processing is basically distinguished into three types which black tea, green tea, and oolong tea. Green tea is processed by heating and drying the leaves. Green tea factories in Indonesia are generally using the process of drying by panning the leaves. It is more recommended to use the fluidization process to speed up the drying process as the quality of the tea can be maintained. Bubbling fluidization is expected to occur in this research. It is a process of bubbles are formed in the fluidization. The effectiveness of the drying process in a fluidized bed dryer machine needs to be improved by using a CFD simulation method to proof that umf < u < ut, where the average velocity value is limited by the minimum and the maximum velocity of the calculation the experimental data. The minimum and the maximum velocity value of the fluidization is 0.96 m/s and 8.2 m/s. The result of the simulation obtained that the average velocity of the upper bed part is 1.81 m/s. From the results obtained, it can be concluded that the calculation and the simulation data is in accordance with the condition of bubbling fluidization in fluidized bed dryer.

  11. CFD Analysis to Calculate the Optimal Air Velocity in Drying Green Tea Process Using Fluidized Bed Dryer

    Directory of Open Access Journals (Sweden)

    Yohana Eflita

    2018-01-01

    Full Text Available Tea processing is basically distinguished into three types which black tea, green tea, and oolong tea. Green tea is processed by heating and drying the leaves. Green tea factories in Indonesia are generally using the process of drying by panning the leaves. It is more recommended to use the fluidization process to speed up the drying process as the quality of the tea can be maintained. Bubbling fluidization is expected to occur in this research. It is a process of bubbles are formed in the fluidization. The effectiveness of the drying process in a fluidized bed dryer machine needs to be improved by using a CFD simulation method to proof that umf < u < ut, where the average velocity value is limited by the minimum and the maximum velocity of the calculation the experimental data. The minimum and the maximum velocity value of the fluidization is 0.96 m/s and 8.2 m/s. The result of the simulation obtained that the average velocity of the upper bed part is 1.81 m/s. From the results obtained, it can be concluded that the calculation and the simulation data is in accordance with the condition of bubbling fluidization in fluidized bed dryer.

  12. Intestinal alkaline phosphatase: novel functions and protective effects.

    Science.gov (United States)

    Lallès, Jean-Paul

    2014-02-01

    Important protective roles of intestinal alkaline phosphatase (IAP)--including regulation of intestinal surface pH, absorption of lipids, detoxification of free nucleotides and bacterial lipopolysaccharide, attenuation of intestinal inflammation, and possible modulation of the gut microbiota--have been reviewed recently. IAP is modulated by numerous nutritional factors. The present review highlights new findings on the properties of IAP and extends the list of its protective functions. Critical assessment of data suggests that some IAP properties are a direct result of dephosphorylation of proinflammatory moieties, while others (e.g., gut barrier protection and microbiota shaping) may be secondary to IAP-mediated downregulation of inflammation. IAP and tissue-nonspecific alkaline phosphatase isoforms characterize the small intestine and the colon, respectively. Gastrointestinal administration of exogenous IAP ameliorates gut inflammation and favors gut tissue regeneration, whereas enteral and systemic IAP administration attenuates systemic inflammation only. Finally, the IAP gene family has a strong evolutionary link to food-driven changes in gastrointestinal tract anatomy and microbiota composition. Therefore, stimulation of IAP activity by dietary intervention is a goal for preserving gut homeostasis and health by minimizing low-grade inflammation. © 2013 International Life Sciences Institute.

  13. Effect of alkaline pretreatment on delignification of wheat straw.

    Science.gov (United States)

    Asghar, Umar; Irfan, Muhammad; Iram, Mehvish; Huma, Zile; Nelofer, Rubina; Nadeem, Muhammad; Syed, Quratulain

    2015-01-01

    This study was conducted to analyse structural changes through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) after alkaline pretreatment of wheat straw for optimum steaming period. During the study, 2 mm size of substrate was soaked in 2.5% NaOH for 1 h at room temperature and then autoclaved at 121°C for various steaming time (30, 60, 90 and 120 min). Results revealed that residence time of 90 min at 121°C has strong effect on substrate, achieving a maximum cellulose content of 83%, delignification of 81% and hemicellulose content of 10.5%. Further SEM and FTIR spectroscopy confirmed structural modification caused by alkaline pretreatment in substrate. Maximum saccharification yield of 52.93% was achieved with 0.5% enzyme concentration using 2.5% substrate concentration for 8 h of incubation at 50°C. This result indicates that the above-mentioned pretreatment conditions create accessible areas for enzymatic hydrolysis.

  14. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  15. Potentiometric assay for acid and alkaline phosphatase

    International Nuclear Information System (INIS)

    Koncki, Robert; Ogonczyk, Dominika; Glab, Stanislaw

    2005-01-01

    Simple potentiometric kinetic assay for evaluation of acid and alkaline phosphatase activity has been developed. Enzymatically catalyzed hydrolysis of monofluorophosphate, the simplest inorganic compound containing P-F bond, has been investigated as the basis of the assays. Fluoride ions formed in the course of the hydrolysis of this specific substrate have been detected using conventional fluoride ion-selective electrode based on membrane made of lanthanum fluoride. The key analytical parameters necessary for sensitive and selective detection of both enzymes have been assessed. Maximal sensitivity of the assays was observed at monofluorophosphate concentration near 10 -3 M. Maximal sensitivity of acid phosphatase assay was found at pH 6.0, but pH of 4.8 is recommended to eliminate effects from alkaline phosphatase. Optimal pH for alkaline phosphatase assay is 9.0. The utility of the developed substrate-sensor system for determination of acid and alkaline phosphatase activity in human serum has been demonstrated

  16. Optical properties of alkaline earth borate glasses

    African Journals Online (AJOL)

    user

    applications in the field of optical fibers, optoelectronic devices; radiation shields, surgical lasers and their glass ceramic counter parts have wide range of applications (Rajasree et al., 2011; Sharma et al., 2007, Limkitjaroenporn et al., 2010). Boric acid. (H3BO3) form stable glasses with alkaline earth oxides (R= MgO, CaO, ...

  17. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    IAS Admin

    and yellow colour appears. Initial colour remains but fades. Orange colour appears. Yellow colour appears. Carbohydrates. Monosaccharide. Disaccharide. + Alkaline ferricyanide (shake for 5 minutes). Colour disappears. Colour does not disappear. Put the test tube in boiling water for 10 seconds. Put the test tube in boiling.

  18. Optimization of alkaline protease production from Pseudomonas ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... the metal ions tested. Key words: Alkaline protease, casein agar, meat waste contaminated soil, Pseudomonas fluorescens. INTRODUCTION. Proteases are the most important industrial enzymes that execute a wide variety of functions and have various important biotechnological applications (Mohen et al.,.

  19. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  20. Alkaline earth metal catalysts for asymmetric reactions.

    Science.gov (United States)

    Kobayashi, Shū; Yamashita, Yasuhiro

    2011-01-18

    The group 2 alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) are among the most common elements on Earth, abundant in both the sea and the Earth's crust. Although they are familiar in our daily lives, their application to organic synthesis has, so far, been limited. Some particularly useful properties of these elements include (i) low electronegativity, (ii) a stable oxidation state of +2, meaning that they can potentially form two covalent bonds with anions, and (iii) the ability to occupy a variety of coordination sites due to their large ionic radius. Furthermore, the alkaline earth metals, found between the group 1 and group 3 elements, show mild but significant Lewis acidity, which can be harnessed to control coordinative molecules via a Lewis acid-base interaction. Taken together, these characteristics make the metals Ca, Sr, and Ba very promising components of highly functionalized acid-base catalysts. In this Account, we describe the development of chiral alkaline earth metal catalysts for asymmetric carbon-carbon bond-forming reactions. Recently prepared chiral alkaline earth metal complexes have shown high diastereo- and enantioselectivities in fundamental and important chemical transformations. We chose chiral bisoxazoline (Box) derivatives bearing a methylene tether as a ligand for chiral modification. These molecules are very useful because they can covalently coordinate to alkaline earth metals in a bidentate fashion through deprotonation of the tether portion. It was found that chiral calcium-Box complexes could successfully promote catalytic asymmetric 1,4-addition and [3 + 2] cycloaddition reactions with high diastereo- and enantioselectivities. Both the calcium-Box complexes and chiral strontium-bis-sulfonamide and chiral barium-BINOLate complexes could catalyze asymmetric 1,4-addition reactions with high enantioselectivities. Furthermore, we designed a calcium-neutral coordinative ligand complex as a new type of chiral alkaline

  1. Matrix solution of point kinetic equation in a fluidized bed nuclear reactor

    International Nuclear Information System (INIS)

    Vilhena, M.T. de; Claeyssen, J.R.

    1990-01-01

    The purpose of this work is to solve the point kinetic equation for a Fluidized Bed Nuclear Reactor by matrix series formulation, showing it is a simple and accurate method, observing this is a scale problem of Stiff type for small time. (author)

  2. Membrane assisted fluidized bed reactor: experimental demonstration for partial oxidation of methanol

    NARCIS (Netherlands)

    Deshmukh, S.A.R.K.

    2004-01-01

    In this thesis the reactor concept has been developed on the basis of an experimental study on the effect of fluidization conditions on the membrane permeation rate in a MAFBR, the extent of gas back mixing and the tube-to-bed heat transfer rates in the presence of membrane bundles with and without

  3. PET investigation of a fluidized particle : spatial and temporal resolution and short term motion

    NARCIS (Netherlands)

    Hoffmann, AC; Dechsiri, C; van de Wiel, F; Dehling, HG

    The motion of a single particle in a fluidized bed has been followed with high temporal and spatial resolution using an ECAT EXACT HR+ PET camera. An account is given of the analysis of the output from the camera, and the calculation of the particle position. The particle position was determined

  4. Conceptual design of a fluidized bed nuclear reactor : Statics, dynamics and safety-related aspects

    NARCIS (Netherlands)

    Agung, A.

    2007-01-01

    In this thesis a conceptual design of an innovative high temperature reactor based on the fluidization principle (FLUBER) is proposed. The reactor should satisfy the following requirements: (a) modular and low power, (b)) large shutdown margin, (c) able to produce power when the bed of particles

  5. Application of point kinetic model in the study of fluidized bed reactor dynamic

    International Nuclear Information System (INIS)

    Borges, Volnei; Vilhena, Marco Tullio de; Streck, Elaine E.

    1995-01-01

    In this work the dynamical behavior of the fluidized bed nuclear reactor is analysed. The main goal consist to study the effect of the acceleration term in the point kinetic equations. Numerical simulations are reported considering constant acceleration. (author). 7 refs, 4 figs

  6. A discrete particle simulation study on the influence of restitution coefficient on spout fluidized bed dynamics

    NARCIS (Netherlands)

    van Buijtenen, M.S.; Deen, N.G.; Heinrich, Stefan; Antonyuk, Sergiy; Kuipers, J.A.M.

    2009-01-01

    Spout fluidized beds find widespread application in the process industry in granulation processes, in which efficient contacting between large particles, droplets and gas is of paramount importance. However, detailed understanding of the complex behavior of these systems is lacking. In this paper,

  7. Improvement of the discrete element model for the study of granulation in a spout fluidized bed

    NARCIS (Netherlands)

    van Buijtenen, M.S.; Deen, N.G.; Heinrich, Stefan; Kuipers, J.A.M.; Antonyuk, Sergiy

    2007-01-01

    Spout fluidized beds find widespread application in the process industry in granulation processes, in which efficient contacting between large particles, droplets and gas is of paramount importance. However, detailed understanding of the complex behavior of these systems is lacking. In this paper we

  8. Monitoring granulation rate processes using three PAT tools in a pilot-scale fluidized bed.

    Science.gov (United States)

    Tok, Ai Tee; Goh, Xueping; Ng, Wai Kiong; Tan, Reginald B H

    2008-01-01

    The purpose of this research was to analyze and compare the responses of three Process Analytical Technology (PAT) techniques applied simultaneously to monitor a pilot-scale fluidized bed granulation process. Real-time measurements using focused beam reflectance measurement (Lasentec FBRM) and near-infra red spectroscopy (Bruker NIR) were taken by inserting in-line probes into the fluidized bed. Non-intrusive acoustic emission measurements (Physical Acoustic AE) were performed by attaching piezoelectric sensors on the external wall of the fluidized bed. Powder samples were collected at regular intervals during the granulation process and characterized offline using laser diffraction, scanning electron microscopy, stereo-optical microscopy and loss on drying method. PAT data comprising chord length distribution and chord count (from FBRM), absorption spectra (from NIR) and average signal levels and counts (from AE) were compared with the particle properties measured using offline samples. All three PAT techniques were able to detect the three granulation regimes or rate processes (wetting and nucleation, consolidation and growth, breakage) to varying degrees of sensitivity. Being dependent on optical signals, the sensitivities of the FBRM and NIR techniques were susceptible to fouling on probe windows. The AE technique was sensitive to background fluidizing air flows and external interferences. The sensitivity, strengths and weaknesses of the PAT techniques examined may facilitate the selection of suitable PAT tools for process development and scale-up studies.

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  10. Investigation on side-spray fluidized bed granulation with swirling airflow.

    Science.gov (United States)

    Wong, Poh Mun; Chan, Lai Wah; Heng, Paul Wan Sia

    2013-03-01

    Top-spray fluidized bed granulation with axial fluidization airflow from the bottom of the granulator is well-established in the pharmaceutical industry. The application of swirling airflow for fluidized bed granulation was more recently introduced. This study examined the effects of various process parameters on the granules produced by side-spray fluidized bed with swirling airflow using the central composite and Box-Behnken design of experiment. Influence of the amount of binder solution, spray rate, and distance between spray nozzle and powder bed were initially studied to establish operationally viable values for these parameters. This was followed by an in-depth investigation on the effects of inlet airflow rate, atomizing air pressure and distance between spray nozzle and powder bed on granule properties. It was found that the amount of binder solution had a positive correlation with granule size and percentage of lumps but a negative correlation with size distribution and Hausner ratio of the granules. Binder solution spray rate was also found to affect the granules size. High drug content uniformity was observed in all the batches of granules produced. Both inlet airflow rate and atomizing air pressure were found to correlate negatively with granule size and percentage of lumps but correlate positively with the size distribution of the granule produced. Percentage of fines was found to be significantly affected by inlet airflow rate. Distance between spray nozzle and powder bed generally affected the percentage of lumps.

  11. Investigation on Calcination Behaviors of Coal Gangue by Fluidized Calcination in Comparison with Static Calcination

    Directory of Open Access Journals (Sweden)

    Shuai Yuan

    2017-02-01

    Full Text Available In order to comprehensively utilize coal gangue, we present fluidized calcination as a new thermal technology for activating coal gangue and systematical study was conducted in comparison with static calcination. The calcined products obtained by different calcination methods under various temperatures were characterized by the means of X-ray diffraction (XRD, thermal gravimetry-differential scanning calorimeter (TG-DSC, Fourier transform-infrared spectroscopy (FT-IR and scanning electron microscope-energy dispersive spectrometer (SEM-EDS. Chemical and physical characteristics such as aluminium leaching rate, chemical oxygen demand and whiteness of calcined products were also investigated. The results show that aluminium leaching rate could reach to the maximal value 74.42% at 500 °C by fluidized calcination, while the maximal value of 66.33% could be reached at 600 °C by static calcination. Products by fluidized calcination obtained higher whiteness and lower chemical oxygen demand (COD under the same calcination temperature. The well-crystallized kaolinite transform to amorphous meta-kaolinite under 600 °C and mullite presence under 1000 °C according to phase transformation, chemical bond variation and microstructure evolution analysis. Fluidized calcination was more efficiently for combustion of carbon/organic matter and dehydroxylation of kaolinite, which might applied in coal gangue industry in future.

  12. Thermal gasification of village rice husk and sawdust in fluidized bed : gasifier operation and thermal efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Gangavati, P.B. [Basaveshwar Engineering College, Bagalkot (India); Mishra, I.M.; Prasad, B. [Indian Inst. of Technology, Roorkee (India). Dept. of Chemical Engineering

    2006-07-01

    An air gasification process for converting rice husks into a renewable fuel was presented. The gasification process was conducted on a fluidized bed gasifier unit comprised of a fluidized bed reactor; an air supply unit; biomass-feeding unit; a high efficiency cyclone; and an after-burner. The performance of the gasifier was evaluated under a range of different operating conditions, fluidization velocities, and equivalence ratios. The aim of the study was to understand the gasification characteristics of the rice husk and compare it with the kinetic behaviour of sawdust. Temperature profiles were analyzed, as well as gas composition and heating values, as well as carbon conversion and thermal efficiencies. The results of the gasification experiments indicated that thermal efficiencies decreased as the fluidization velocity increased. The gas yield increased and the higher heating values decreased with increases in the equivalence ratio (ER) at all the tested velocities. A maximum efficiency of approximately 57 per cent was obtained for the village rice husk, while efficiencies of 72.3 per cent were obtained for the sawdust. 7 ref., 2 figs.

  13. Air gasification of rice husk in a dual distributor type fluidized bed gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Mansaray, K.G.; Ghaly, A.E. [Dalhousie University, Halifax, Nova Scotia (Canada). Biological Engineering Dept.; Al-Taweel, A.M. [Dalhousie University, Halifax, Nova Scotia (Canada). Chemical Engineering Dept.; Hamdullahpur, F.; Ugursal, V.I. [Dalhousie University, Halifax, Nova Scotia (Canada). Mechanical Engineering Dept.

    1999-10-01

    In this study, a dual distributor type fluidized bed gasifier was used for the air gasification of rice husk in view of producing fuel gas. The effects of varying fluidization velocity (0.22, 0.28 and 0.33 m s{sup -1}) and equivalence ratio (0.25, 0.30 and 0.35) on the gasifier performance were discussed. The steady state temperature varied between 665 and 830 degrees C. The fluidization velocity of 0.22 m s{sup -1} and equivalence ratio of 0.25 appeared to be the optimum conditions with respect to the quality of gas. The mole fractions of the combustible components reached their maximum values at these conditions with a typical gas composition of 4% H{sub 2}, 5% hydrocarbons (CH{sub 4}, C{sub 2}H{sub 2}, C{sub 2}H{sub 4} and C{sub 2}H{sub 6}), 15% CO{sub 2}, 20% CO and 57% N{sub 2}. The higher heating value of the gas obtained at these fluidization velocity and equivalence ratio (3.09 - 5.03 MJ Nm{sup -3}) compared very well with published data from air-blown biomass gasifiers of similar scale of operation. The gas yield and carbon conversion were in the range of 1.30 to 1.98 Nm{sup 3} kg{sup -1} and 55.0 to 81.0%, respectively.

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

    NARCIS (Netherlands)

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

    2009-01-01

    A system to remove in situ char/ash from hot pyrolysis vapors has been developed and tested at the University of Twente. The system consists of a continuous fluidized bed reactor (0.7 kg/h) with immersed filters (wire mesh, pore size 5 μm) for extracting pyrolysis vapors. Integration of the filter

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

    NARCIS (Netherlands)

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

    1990-01-01

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

  16. [Analysis of novel style biological fluidized bed A/O combined process in dyeing wastewater treatment].

    Science.gov (United States)

    Wei, Chao-Hai; Huang, Hui-Jing; Ren, Yuan; Wu, Chao-Fei; Wu, Hai-Zhen; Lu, Bin

    2011-04-01

    A novel biological fluidized bed was designed and developed to deal with high-concentration refractory organic industrial wastewater. From 12 successful projects, three cases of dyeing wastewater treatment projects with the scale of 1200, 2000 and 13000 m3/d respectively were selected to analyze the principle of treating refractory organic wastewater with fluidized bed technology and discuss the superiority of self-developed biological fluidized bed from the aspects of technical and economic feasibility. In the three cases, when the hydraulic retention time (HRT) of biological system were 23, 34 and 21. 8 h, and the volume loading of influents (COD) were 1.75, 4.75 and 2.97 kg/(m3 x d), the corresponding COD removal were 97.3%, 98.1% and 95.8%. Furthermore the operating costs of projects were 0.91, 1.17 and 0.88 yuan per ton of water respectively. The index of effluent all met the 1st grade of Guangdong Province wastewater discharge standard. Results showed that the biological fluidized bed had characteristics of shorter retention time, greater oxygen utilization rate, faster conversion rate of organic pollutants and less sludge production, which made it overcome the shortcomings of traditional methods in printing and dyeing wastewater treatment. Considering the development of technology and the combination of ecological security and recycling resources, a low-carbon wastewater treatment process was proposed.

  17. Industrial Scale Synthesis of Carbon Nanotubes Via Fluidized Bed Chemical Vapor Deposition: A Senior Design Project

    Science.gov (United States)

    Smith, York R.; Fuchs, Alan; Meyyappan, M.

    2010-01-01

    Senior year chemical engineering students designed a process to produce 10 000 tonnes per annum of single wall carbon nanotubes (SWNT) and also conducted bench-top experiments to synthesize SWNTs via fluidized bed chemical vapor deposition techniques. This was an excellent pedagogical experience because it related to the type of real world design…

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

    DEFF Research Database (Denmark)

    Jensen, Anker; Johnsson, Jan Erik

    1997-01-01

    Simulations with a mathematical model of a pressurized bubbling fluidized-bed combustor (PFBC) combined with a kinetic model for NO formation and reduction are reported. The kinetic model for NO formation and reduction considers NO and NH3 as the fixed nitrogen species, and includes homogeneous r...

  19. FLUIDIZED BED STEAM REFORMING FOR TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE

    Energy Technology Data Exchange (ETDEWEB)

    HEWITT WM

    2011-04-08

    This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of fluidized bed steam reforming and its possible application to treat and immobilize Hanford low-activity waste.

  20. Fluidized Bed Steam Reforming For Treatment And Immobilization Of Low-Activity Waste

    International Nuclear Information System (INIS)

    Hewitt, W.M.

    2011-01-01

    This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of fluidized bed steam reforming and its possible application to treat and immobilize Hanford low-activity waste.

  1. Application of image processing on struvite recovery from swine wastewater by using the fluidized bed.

    Science.gov (United States)

    Ye, Zhi-Long; Deng, Yujun; Ye, Xin; Lou, Yaoyin; Chen, Shaohua

    2018-01-01

    Fluidized granulation is one of the common methods used in wastewater treatment and resource recovery with harvesting millimeter-scale large particles. Presently, effective methods are lacking to measure the fluidized granules ranging from micro- to millimeter scales, with the consequence of ineffectively controlling and optimizing the granulation process. In this work, recovering struvite (MgNH 4 PO 4 ·6H 2 O) from swine wastewater by using a fluidized bed was taken as an example. Image processing was applied to analyze the properties of different types of struvite granules, including morphology, particle size distribution, number density and mass concentration. Four stages of the struvite crystal evolution were therefore defined: aggregation, aggregate compaction, cluster-agglomerating and coating growth. These stages could occur simultaneously or sequentially. Up-flow rates of 30-80 mm/s in the fluidized bed sustained 600-876 g/L granular solids. Results revealed that the coating-growth granules were formed with compact aggregates or cluster-agglomerating granules as the nuclei. The growth rates for the different types of particles, including population growth, mass increase and particle size enlargement, were determined. In final, a schematic illustration for struvite granulation process is also presented.

  2. A numerical study of fluidization behavior of Geldart A particles using a discrete particle model

    NARCIS (Netherlands)

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

    2004-01-01

    This paper reports on a numerical study of fluidization behavior of Geldart A particles by use of a 2D soft-sphere discrete particle model (DPM). Some typical features, including the homogeneous expansion, gross particle circulation in the absence of bubbles, and fast bubbles, can be clearly

  3. Effects of fluidized gas desulfurization (FGD) gypsum on non-target freshwater and sediment dwelling organims

    Science.gov (United States)

    Fluidized gas desulfurization gypsum is a popular agricultural soil amendment used to increase calcium and sulfur contents, and reduce aluminum toxicity. Due to its surface application in conservation tillage systems and high solubility, the soluble components of gypsum may be transferred with agri...

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

    Indian Academy of Sciences (India)

    Power generation based on biomass holds a considerable promise in Punjab, which has huge biomass resources from crop production system and agro industries. ... ever, there are some biomass residues concentrated at specific locations, where demand for energy also exists. Fluidized-bed combustion process seems to ...

  5. Behaviour of Inorganic Constituents of Municipal Sewage Sludge during Fluidized-Bed Combustion.

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Pohořelý, Michael; Trnka, Otakar

    2007-01-01

    Roč. 61, 3 (2007) , s. 181-185 ISSN 0366-6352 R&D Projects: GA AV ČR(CZ) IAA4072201 Institutional research plan: CEZ:AV0Z40720504 Keywords : sewage sludge * heavy metals * fluidized-bed combustion Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.367, year: 2007

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-09-01

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

  7. Combustion of Liquid Bio-Fuels in an Internal Circulating Fluidized Bed

    Czech Academy of Sciences Publication Activity Database

    Miccio, F.; Kalisz, S.; Baxter, D.; Svoboda, Karel

    2008-01-01

    Roč. 143, 1-3 (2008), s. 172-179 ISSN 1385-8947 Institutional research plan: CEZ:AV0Z40720504 Keywords : internal circulating fluidized bed * liquid fuel * combustion Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.813, year: 2008

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

    Czech Academy of Sciences Publication Activity Database

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

    2016-01-01

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

  9. A Review of Eulerian Simulation of Geldart A Particles in Gas-Fluidized Beds

    NARCIS (Netherlands)

    Wang, J.

    2009-01-01

    Although great progress has been made in modeling the gas fluidization of Geldart B and D particles and dilute gas−solid flow by standard Eulerian approach, researchers have shown that, because of the limitation of computational resources and the formation of subgrid-scale (SGS) heterogeneous

  10. Fluidized bed electrodes with high carbon loading for water desalination by capacitive deionization

    NARCIS (Netherlands)

    Doornbusch, G.J.; Dykstra, J.E.; Biesheuvel, P.M.; Suss, M.E.

    2016-01-01

    The use of carbon flow electrodes has significantly impacted electrochemical energy storage and capacitive deionization (CDI), but device performance is limited as these electrodes cannot surpass ∼20 wt% carbon while maintaining flowability. We here introduce flowable fluidized bed electrodes

  11. The Role of Membrane Fluidization in the Gel-Assisted Formation of Giant Polymersomes.

    Directory of Open Access Journals (Sweden)

    Adrienne C Greene

    Full Text Available Polymersomes are being widely explored as synthetic analogs of lipid vesicles based on their enhanced stability and potential uses in a wide variety of applications in (e.g., drug delivery, cell analogs, etc.. Controlled formation of giant polymersomes for use in membrane studies and cell mimetic systems, however, is currently limited by low-yield production methodologies. Here, we describe for the first time, how the size distribution of giant poly(ethylene glycol-poly(butadiene (PEO-PBD polymersomes formed by gel-assisted rehydration may be controlled based on membrane fluidization. We first show that the average diameter and size distribution of PEO-PBD polymersomes may be readily increased by increasing the temperature of the rehydration solution. Further, we describe a correlative relationship between polymersome size and membrane fluidization through the addition of sucrose during rehydration, enabling the formation of PEO-PBD polymersomes with a range of diameters, including giant-sized vesicles (>100 μm. This correlative relationship suggests that sucrose may function as a small molecule fluidizer during rehydration, enhancing polymer diffusivity during formation and increasing polymersome size. Overall the ability to easily regulate the size of PEO-PBD polymersomes based on membrane fluidity, either through temperature or fluidizers, has broadly applicability in areas including targeted therapeutic delivery and synthetic biology.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1975-07-01

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

  13. High-Temperature Reaction in the Freeboard Region above a Bubbling Fluidized Bed

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Trnka, Otakar; Pohořelý, Michael; Svoboda, Karel

    2010-01-01

    Roč. 49, č. 6 (2010), s. 2672-2980 ISSN 0888-5885 R&D Projects: GA AV ČR IAA400720701 Institutional research plan: CEZ:AV0Z40720504 Keywords : fluidization * freeboard * performance Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.071, year: 2010

  14. Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

    Science.gov (United States)

    Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

    2017-05-01

    Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

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

    NARCIS (Netherlands)

    Thy, P.; Jenkins, B.M.; Williams, R.B.; Lesher, C.E.; Bakker, R.R.

    2010-01-01

    Petrographic techniques have been used to examine bed materials from fluidized bed combustion experiments that utilized wood and rice straw fuel blends. The experiments were conducted using a laboratory-scale combustor with mullite sand beds, firing temperatures of 840 to 1030 °C, and run durations

  16. Experiment and modeling of low-concentration methane catalytic combustion in a fluidized bed reactor

    International Nuclear Information System (INIS)

    Yang, Zhongqing; Yang, Peng; Zhang, Li; Guo, Mingnv; Ran, Jingyu

    2016-01-01

    Highlights: • The catalytic combustion of 0.15~3 vol. % low concentration methane in a fluidized bed was studied. • A mathematical model was proposed on the basis of gas–solid flow theory. • A comparative analysis of the established model with plug flow, mixed flow and K-L models was carried out. • The axial methane profile along fluidized bed was predicted by using the mathematical model. • The bed temperature has greater impact on methane conversion than fluidized velocity. - Abstract: This study undertakes a theoretical analysis and an experimental investigation into the characteristics of low-concentration methane catalytic combustion in a bubbling fluidized bed reactor using 0.5 wt.% Pd/Al 2 O 3 as catalytic particles. A mathematical model is established based on gas–solid flow theory and is used to study the effects of bed temperature and fluidized velocity on methane catalytic combustion, and predict the dimensionless methane concentration axial profile in reactor. It is shown that methane conversion increases with bed temperature, but decreases with increasing fluidized velocity. These theoretical results are found to correlate well with the experimental measurement, with a deviation within 5%. A comparative analysis of the developed model with plug flow, mixed flow and K-L models is also carried out, and this further verifies that the established model better reflects the characteristics of low-concentration methane catalytic combustion in a bubbling fluidized bed. Using this reaction model, it was found that the difference in methane conversion between dense and freeboard zones gradually increases with bed temperature; the dense zone reaction levels off at 650 °C, thereby minimizing the difference between the dense and freeboard regions to around 15%. With an increase in bed temperature, the dimensionless methane concentration in the dense zone decreases exponentially, while in the splash zone, it varies from an exponential decay to a

  17. Combustion of gases released from peat or biomass in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Raiko, R. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

    1996-12-01

    Temperature and gas concentration experiments have been conducted to determine at what temperature carbon monoxide, methane and propane begin to react within the particulate phase of a bubbling fluidized bed. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 50 mm surrounded by an electric heater. Two different natural quartz sands were used (d{sub p} =0.35 mm and 0.6 mm). The bed height used varied between 100 and 260 mm (in unfluidized state). A porous plate distributor, made of kaowool, was used to avoid jets appearing at the distributor. The bed was operated at incipient fluidization (u = 5.9-9 cm/s). The bed temperatures used ranged from 600 deg C to 850 deg C. It was found that carbon monoxide, methane and propane react inside a fluidized bed, but often other conditions than temperature have a considerable effect on the rate of the reaction. The critical temperature was found to be 650 deg C for propane and carbon monoxide and 700 deg C for methane. With under-stoichiometric mixture of carbon monoxide and air the heat release can be over 2.5 MW/m{sup 3} when bed temperature is 650 deg C. According to these experiments it is obvious that the reaction mechanism for carbon monoxide oxidation inside a fluidized bed differs greatly from that of gas phase only. The results of our more than 1300 test runs show clearly the varying effects of the different bed materials. Even with the same bed material totally different results can be obtained. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies was conducted with both fresh bed particles and used bed particles. Also the effect of commonly used ingredients, like limestone and dolomite, was tested. A global model for carbon monoxide oxidation inside a fluidized bed was introduced. The model was tested against measured data from the laboratory-scale fluidized bed test rig. (Abstract Truncated)

  18. Study of the fluidized bed chemical vapor deposition process on very dense powder for nuclear applications

    International Nuclear Information System (INIS)

    Vanni, Florence

    2015-01-01

    This thesis is part of the development of low-enriched nuclear fuel, for the Materials Test Reactors (MTRs), constituted of uranium-molybdenum particles mixed with an aluminum matrix. Under certain conditions under irradiations, the U(Mo) particles interact with the aluminum matrix, causing unacceptable swelling of the fuel plate. To inhibit this phenomenon, one solution consists in depositing on the surface of the U(Mo) particles, a thin silicon layer to create a barrier effect. This thesis has concerned the study of the fluidized bed chemical vapor deposition (CVD) process to deposit silicon from silane, on the U(Mo) powder, which has an exceptional density of 17,500 kg/m 3 . To achieve this goal, two axes were treated during the thesis: the study and the optimization of the fluidization of a so dense powder, and then those of the silicon deposition process. For the first axis, a series of tests was performed on a surrogate tungsten powder in different columns made of glass and made of steel with internal diameters ranging from 2 to 5 cm, at room temperature and at high temperature (650 C) close to that of the deposits. These experiments helped to identify wall effects phenomena within the fluidized bed, which can lead to heterogeneous deposits or particles agglomeration. Some dimensions of the fluidization columns and operating conditions allowing a satisfactory fluidization of the powder were identified, paving the way for the study of silicon deposition. Several campaigns of deposition experiments on the surrogate powder and then on the U(Mo) powder were carried out in the second axis of the study. The influence of the bed temperature, the inlet molar fraction of silane diluted in argon, and the total gas flow of fluidization, was examined for different diameters of reactor and for various masses of powder. Morphological and structural characterization analyses (SEM, XRD..) revealed a uniform silicon deposition on all the powder and around each particle

  19. Osteocalcin and bone-specific alkaline phosphatase in Sickle cell ...

    African Journals Online (AJOL)

    specific alkaline phosphatase (b-AP) total protein levels were evaluated as indicators of bone turnover in twenty patients with sickle cell haemoglobinopathies and in twenty normal healthy individuals. The serum bonespecific alkaline phosphatase ...

  20. Performances of continuous dryer with inert medium fluidized bed

    Directory of Open Access Journals (Sweden)

    Arsenijević Zorana Lj.

    2008-01-01

    Full Text Available A fluid bed dryer with inert particles represents a very attractive alternative to other drying technologies according to the main efficiency criteria, i.e. specific water evaporation rate, specific heat consumption and speci­fic air consumption. A high drying efficiency results from the large con­tact area and from the large temperature difference between the inlet and outlet air. A rapid mixing of the particles leads to nearly isothermal conditions throughout the bed. A fluid bed dryer with inert particles was used for drying of slurries. Experiments were performed in a cylindrical column 215 mm in diameter with glass spheres as inert particles. In this paper, results of drying experi­ments with slurries of Zineb fungicide, copper hydroxide, calcium carbo­nate and pure water used as the feed material are presented. In our fluidized bed we successfully dried a number of other materials such as: fungicides and pesticides (Ziram, Propineb, Mangozeb, copper oxy-chloride, copper oxy-sulphate, Bordeaux mixture, other inorganic compounds (calcium sulphate, cobalt carbonate, electrolytic copper, sodium chloride, and a complex compound (organo-bentonite. The effects of operating conditions on dryer throughput and product quality were investigated. Main performance criteria, i.e. specific water evaporation rate, specific heat consumption and specific air consumption, were quantified. Temperature profile along the bed was mapped, and nearly isothermal conditions were found due to thorough mixing of the particles. Analysis of drying and energy efficiencies as a function of inlet and outlet air temperature difference was performed for deeper insight in dryer behavior and for optimizing dryer design and operation from an energy point of view. A simple mathematical model based on an overall heat balance predicts the dryer performance quite well. The industrial prototype with fluid bed of 0.8 m in diameter and capacity 650 kg of evaporated moisture per

  1. Characterization of biofilm in 200W fluidized bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Michelle H. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Saurey, Sabrina D. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lee, Brady D. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Parker, Kent E. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Eisenhauer, Emalee E. R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Cordova, Elsa A. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Golovich, Elizabeth C. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

    2014-09-29

    Contaminated groundwater beneath the 200 West Area at the Hanford Site in Southeast Washington is currently being treated using a pump and treat system to remove organics, inorganics, radionuclides, and metals. A granular activated carbon-based fluidized bed reactor (FBR) has been added to remove nitrate, hexavalent chromium and carbon tetrachloride. Initial analytical results indicated the microorganisms effectively reduced many of the contaminants to less than cleanup levels. However shortly thereafter operational upsets of the FBR include carbon carry over, over production of microbial extracellular polymeric substance (biofilm) materials, and over production of hydrogen sulfide. As a result detailed investigations were undertaken to understand the functional diversity and activity of the microbial community present in the FBR over time. Molecular analyses including terminal restriction fragment length polymorphism analysis, quantitative polymerase chain reaction and fluorescent in situ hybridization analyses were performed on the microbial community extracted from the biofilm within the bed and from the inoculum, to determine functional dynamics of the FBR bed over time and following operational changes. Findings from these analyses indicated: 1) the microbial community within the bed was completely different than community used for inoculation, and was likely from the groundwater; 2) analyses early in the testing showed an FBR community dominated by a few Curvibacter and Flavobacterium species; 3) the final sample taken indicated that the microbial community in the FBR bed had become more diverse; and 4) qPCR analyses indicated that bacteria involved in nitrogen cycling, including denitrifiers and anaerobic ammonia oxidizing bacteria, were dominant in the bed. These results indicate that molecular tools can be powerful for determining functional diversity within FBR type reactors. Coupled with micronutrient, influent and effluent chemistry

  2. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  3. Strong interaction and QFD

    International Nuclear Information System (INIS)

    Ebata, T.

    1981-01-01

    With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)

  4. Evidence for Quaternary earthquakes from paleo-fluidization structures along the Pernambuco lineament (NE-Brazil).

    Science.gov (United States)

    Nestola, Yago; Balsamo, Fabrizio; Hilario Rego Bezerra, Francisco; Cézar Costa Nogueira, Fancisco; Storti, Fabrizio

    2014-05-01

    Plate tectonics theory postulate that seismicity is mostly restricted to the plate's boundaries. Nevertheless, intraplate earthquakes occur in stable continental areas such as the NE-Brazilian craton, where seismicity is clustered along fault systems reactivating major Neoproterozoic shear zones. Moreover, evidence for tectonic activity is recorded in the Cenozoic post-rift formations, widely outcropping along the coast of the NE-Brazilian passive margin. To investigate such unexpected seismic and tectonic activity we performed a structural field survey along the coastal segment of the Pernambuco shear zone, where the Miocene sandstone of the Barreiras Fm. and the overlying Quaternary post-Barreiras deposits extensively crop out. They are separated by a Tortonian lateritic paleosoil and are affected by mainly extensional faulting, associated with some strike-slip deformation, clustered in N-S, WNW-ESE, and NE-SW trends. In the proximity of the Pernambuco shear zone, in the hinterland of the Recife town, we found evidence for paleo-fluidization structures in post-Barreiras deposits, where mobilized materials include cm-dm-sized, heterogeneous angular clasts in a sandy-dominated matrix. The extent of the exposed fluidized bodies exceeds ~50 m in active quarry walls, the maximum thickness reaches ~3 m, and the depth of fluidization is estimated to be about 30 m. The top seal of fluidized material was provided by a ~80 cm thick clay layer. Such fluidizations are located few hundreds meters far from a major NE-SW-trending, sin-sedimentary extensional fault zone developed in Quaternary deposits, which is consistent with a left-lateral strike-slip sense of shear of the Pernambuco shear zone. Our results further improve the knowledge of paleo-seismic activity along the Pernambuco shear zone and, in particular, provide additional information for the seismic hazard assessment in the high-density populated area of the Recife town.

  5. A Coarse-Grained Two-Fluid Model for Gas-Solid Fluidized Beds

    Directory of Open Access Journals (Sweden)

    S. Schneiderbauer

    2014-03-01

    Full Text Available Due to increasing computer power the numerical simulation of fluidized and moving beds has become feasible. However, while kinetic theory based CFD (Computational Fluid Dynamics has become a valuable design tool for modeling pilot plant scale gassolid fluidized bed reactors, a fully resolved simulation of industrial scale reactor is still nearly unfeasible. It is, therefore, common to use sub-grid models to account for the effect of the small unresolved structures on large resolved scales when using coarse grids. It is generally agreed that the influence of these small scales on the drag force is a key parameter in the prediction of the hydrodynamics of fluidized beds. We present a sub-grid drag modification dealing with the influence of heterogeneous structures on the drag force. It is assumed that these structures appear as distinct clusters of particles within an interstitial dilute particle phase. The clusters and the dilute phase itself consist of homogeneously distributed particles enabling the application of a homogenous drag correlation to these structures. In contrast to the established sub-grid drag modification EMMS (Energy-Minimization Multi-Scale Method, the presented model distinguishes between resolved and unresolved clusters by computing the expectation value of the diameter of the unresolved clusters. This reveals a grid and slip velocity dependent drag modification, which recovers the homogenous drag law as the solids volume fraction approaches the maximum packing of frictional spheres. The presented model is validated on the one hand, in case of industrial scale bubbling and turbulent fluidized beds. On the other hand, the model is applied to the coarse grid simulation of a riser flow. The numerical results obtained on a coarse gird demonstrate that our model reveals fairly good agreement with experimental data of bed expansion and solids volume fraction distributions. Thus, the results proof that the presented drag

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

    Directory of Open Access Journals (Sweden)

    Juan Lu

    Full Text Available A fluidized bed bioreactor containing encapsulated hepatocytes may be a valuable alternative to a hollow fiber bioreactor for achieving the improved mass transfer and scale-up potential necessary for clinical use. However, a conventional fluidized bed bioreactor (FBB operating under high perfusion velocity is incapable of providing the desired performance due to the resulting damage to cell-containing microcapsules and large void volume. In this study, we developed a novel diversion-type microcapsule-suspension fluidized bed bioreactor (DMFBB. The void volume in the bioreactor and stability of alginate/chitosan microcapsules were investigated under different flow rates. Cell viability, synthesis and metabolism functions, and expression of metabolizing enzymes at transcriptional levels in an encapsulated hepatocyte line (C3A cells were determined. The void volume was significantly less in the novel bioreactor than in the conventional FBB. In addition, the microcapsules were less damaged in the DMFBB during the fluidization process as reflected by the results for microcapsule retention rates, swelling, and breakage. Encapsulated C3A cells exhibited greater viability and CYP1A2 and CYP3A4 activity in the DMFBB than in the FBB, although the increases in albumin and urea synthesis were less prominent. The transcription levels of several CYP450-related genes and an albumin-related gene were dramatically greater in cells in the DMFBB than in those in the FBB. Taken together, our results suggest that the DMFBB is a promising alternative for the design of a bioartificial liver system based on a fluidized bed bioreactor with encapsulated hepatocytes for treating patients with acute hepatic failure or other severe liver diseases.

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

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, J.

    1993-12-31

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

  8. Ecological characteristics of the fluidized bed boilers burning low-rank lignite coal

    International Nuclear Information System (INIS)

    Fett, F.N.; Heinbockel, I.; Dersch, J.

    1996-01-01

    The performance simulation of fluidized bed coal plants with Bulgarian low-rank coal has been made. Fluidized bed models, developed in the Institute of Energy Technology, UGN - Siegen, based on one-dimensional compartment-in-series model have been used. The parameters of each data block can be optimized according to criteria chosen in advance. The 'quality of coal - pollution characteristics of the boilers' channel has been chosen as a channel of priority importance. The input information on coal quality characteristics reflects the regression connections between ash content and the other quality components. The wide range of ash value variations of the coal (26 - 44%) causes a lot of problems. Two different models - Atmospheric Bubbling Fluidized Bed Model (ABFB) and Atmospheric Circulated Fluidized Bed Model - have been applied. Some results of computer experiments with ABFB model are given presenting the influence of coal quality on temperature profile in the combustor and on ecological characteristics of the gases. The following interconnections are marked: 1) ash content increase (connected with a net calorific value diminution) leading to a decrease in the temperature along the height of the furnace; 2) dependence of SO 2 concentration on the ash value connected with the 'temperature - NO x ' relationship; 3) decrease in SO 2 concentration caused by the augmentation of Ca/S ratio and the increase in the ash content of the coal. It is concluded that the fluidized bed technology is reliable enough for the Bulgarian low rank lignite because of the low rate of the environmental pollutants. 4 figs., 3 refs

  9. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  10. On performance capabilities of alkaline anolyte in wastewater management

    International Nuclear Information System (INIS)

    Shimkevich, Alexander

    2014-01-01

    A concept for electric converting a saline wastewater into basic solution (pH > 7) with a positive RedOx potential (alkaline anolyte) is considered. Such the medium can be obtained in situ at flowing wastewater via a special electrochemical cell with strongly polarized cathode (generating hydroxide anions) and quasi-equilibrium anode which intensively discharges hydroxide ions to hydroxyl radicals into the wastewater. The radicals will oxidize anions of strong acid and convert them into weak-acid micro precipitates in the flowing basic solution. These renewable nano-sorbents will uninterruptedly co-precipitate radioactive contamination from wastewater and be agglomerated as corrosion by-products in the felt-like anode. The consideration of liquid water as a chemical compound with a wide band gap shows that the anolyte (as a hyper-stoichiometric water, H 2 O 1+|x| ) is a simple and effective tool for varying physical and chemical properties of the aqueous solution due to forced changing its RedOx potential as one needs. This potential as Fermi level in the band gap of liquid water is the most convenient parameter for monitoring and managing the electrochemical potential of the aqueous medium. Its hyper-stoichiometric state is realized when Fermi level is shifted to the top of a valence band. This electro-oxidized state as the alkaline anolyte is characterized by an acceptor level, OH/OH - , partially occupied by electrons. Then, the hydroxyl radical (OH • ) as the strongest oxidizer will oxidize intensively the metal anode and renew its surface for great removal of radio-nuclides from the wastewater due to their large specific area of renewable surface of hydroxide absorber on the felt-like anode. (author)

  11. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  12. Near-infrared spectroscopy monitoring and control of the fluidized bed granulation and coating processes-A review.

    Science.gov (United States)

    Liu, Ronghua; Li, Lian; Yin, Wenping; Xu, Dongbo; Zang, Hengchang

    2017-09-15

    The fluidized bed granulation and pellets coating technologies are widely used in pharmaceutical industry, because the particles made in a fluidized bed have good flowability, compressibility, and the coating thickness of pellets are homogeneous. With the popularization of process analytical technology (PAT), real-time analysis for critical quality attributes (CQA) was getting more attention. Near-infrared (NIR) spectroscopy, as a PAT tool, could realize the real-time monitoring and control during the granulating and coating processes, which could optimize the manufacturing processes. This article reviewed the application of NIR spectroscopy in CQA (moisture content, particle size and tablet/pellet thickness) monitoring during fluidized bed granulation and coating processes. Through this review, we would like to provide references for realizing automated control and intelligent production in fluidized bed granulation and pellets coating of pharmaceutical industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. State of the art and the future fuel portfolio of fluidized bed combustion systems; Status und kuenftiges Brennstoffportfolio bei Wirbelschichtfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Szentannai, Pal; Friebert, Arpad; Winter, Franz [Technische Univ. Wien (Austria). Inst. fuer Verfahrens-, Umwelttechnik und technische Biowissenschaften

    2008-07-01

    Coal, biomass and substitute fuels energetically can be used efficiently and with low pollution in fluidized bed plants. In comparison to biomass there are significant differences between the circulating and stationary fluidized bed technology. The stationary fluidised bed is fed predominantly with biomasses and residual substances. Coal usually is the basis fuel in the circulating fluidised bed. Biomass and residual substances frequently are course-fired. The state of the art is the employment of a broad fuel mixture in small and large fluidized-bed combustion systems. Future developments present an increased use of sewage sludge, fluidized bed combustion systems with wood as a basis fuel, utilization of household waste and the gas production.

  14. An experimental study of heat transfer to a horizontal tube in a large particle fluidized bed at elevated temperature

    Science.gov (United States)

    George, A. H.

    Experimental data for the time-average local heat transfer coefficient to a single horizontal tube in a large particle fluidized bed at elevated temperature, are presented. Refractory particles with surface mean diameter 2.14 mm and 3.23 mm were fluidized by combustion products of propane at bed temperatures of 810 K and 1053 K. The particle sizes are near the largest presently used in pilot plant fluidized bed coal combustors. The superficial gas velocity ranged from that required for minimum fluidization, or slightly packed, to the velocity where slugging first occurred, or the highest velocity air blower capacity would allow. Heat transfer results indicate that a stack of defluidized particles remain on top of the tube at low superficial gas velocities. A very low local heat transfer coefficient was obtained under these conditions. There was less than 10 percent difference in the maximum spatial average heat transfer coefficients for the two particle sizes considered.

  15. Genesis of post-collisional calc-alkaline and alkaline granitoids in Qiman Tagh, East Kunlun, China

    Science.gov (United States)

    Yu, Miao; Feng, Chengyou; Zhao, Yiming; Li, Daxin

    2015-12-01

    The post-collisional magmatism of Qiman Tagh is characterized by the intrusion of voluminous intermediate to felsic granitoids, including syenogranite, monzogranite, granodiorite, tonalite and diorite. The granitoids can be divided into two magmatic suites: Calc-alkaline (CA) and alkaline (Alk), which were emplaced from ~ 236 Ma to ~ 204 Ma. The CA suite contains metaluminous granodiorites and monzogranites. Typical Qiman Tagh CA granodiorites show moderately fractionated REE patterns ((La/Yb)N = 4.35-25.11) with significant negative Eu anomalies (Eu/Eu* = 0.54-1.34), and the primitive mantle-normalized spidergrams show strong depletion of Nb and Sr. The Qiman Tagh CA monzogranites show similar fractionated REE patterns ((La/Yb)N = 2.70-13.5) with less prominent negative Eu anomalies, and the chondrite-normalized spidergrams show strongly depleted Ba, Nb and Sr. The Alk suite, including syenogranite, is highly potassic (K2O/Na2O = 1.09-3.56) and peraluminous (A/CNK = 0.91-1.06). Compared to typical Qiman Tagh CA granodiorites, the Qiman Tagh Alk granitoids can be distinguished by their higher Rb, Nb, Ga/Al, FeO*/MgO, Y/Sr and Rb/Sr, as well as their lower Mg#, MgO, CaO, Al2O3, Sr, Co, V, Eu/Eu*, Ba/Nb, La/Nb, Ba/La and Ce/Nb. The Qiman Tagh CA rocks were most likely to be derived from the partial melting of garnet-amphibolite-facies rocks in the lower crust, leaving behind anhydrous granulite-facies rocks with plagioclase and garnet in the residue. The Alk rocks may have formed by the continued partial melting of granulite-facies rocks at elevated temperatures (> 830 °C).

  16. Study of niobium corrosion in alkaline medium

    International Nuclear Information System (INIS)

    Almeida, S.H. de.

    1987-01-01

    A comparative study of niobium electrochemical behaviour in NaOH and KOH solution, with concentrations between 0,5 and 6,1M is presented. The studies were done through electrochemicals assays, consisting in the corrosion potential and anodic and cathodic polarization curves, complemented by loss of mass experiments. The niobium anodic behaviour in alkaline medium is characterized by passivation occurrence, with a stable film formation. The Na oH solution in alkaline medium are more corrosible to niobium than the KOH solution. The loss of mass assays showed that the corrosion velocit is more dependente of hydroxide concentration in KOH medium than the NaOH medium. (C.G.C.) [pt

  17. Photolysis of alkaline-earth nitrates

    Science.gov (United States)

    Kriger, L. D.; Miklin, M. B.; Dyagileva, E. P.; Anan'ev, V. A.

    2013-02-01

    Peroxynitrite and nitrite ions are the diamagnetic products of photolysis (with light at a wavelength of 253.7 nm) of alkaline-earth nitrates; the paramagnetic products and hydrogen peroxide were not found. The structural water in alkaline-earth nitrate crystals did not affect the qualitative composition of the photodecomposition products. The quantum yield of nitrite ions was 0.0012, 0.0038, 0.0078, and 0.0091 quanta-1 and that of peroxynitrite ions was 0.0070, 0.0107, 0.0286, and 0.0407 quanta-1 for Sr(NO3)2, Ba(NO3)2, Ca(NO3)2 · 4H2O, and Mg(NO3)2 · 6H2O, respectively.

  18. Hydrolysis of alkaline pretreated banana peel

    Science.gov (United States)

    Fatmawati, A.; Gunawan, K. Y.; Hadiwijaya, F. A.

    2017-11-01

    Banana peel is one of food wastes that are rich in carbohydrate. This shows its potential as fermentation substrate including bio-ethanol. This paper presented banana peel alkaline pretreatment and enzymatic hydrolysis. The pretreatment was intended to prepare banana peel in order to increase hydrolysis performance. The alkaline pretreatment used 10, 20, and 30% w/v NaOH solution and was done at 60, 70 and 80°C for 1 hour. The hydrolysis reaction was conducted using two commercial cellulose enzymes. The reaction time was varied for 3, 5, and 7 days. The best condition for pretreatment process was one conducted using 30% NaOH solution and at 80°C. This condition resulted in cellulose content of 90.27% and acid insoluble lignin content of 2.88%. Seven-day hydrolysis time had exhibited the highest reducing sugar concentration, which was7.2869 g/L.

  19. Oxidation catalysts on alkaline earth supports

    Science.gov (United States)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  20. Purification and characterisation of alkaline phosphotase enzyme ...

    African Journals Online (AJOL)

    L'enzyme phosphatase alkaline était purifié de la bactérie Escherichia coli C90 cultivé dans un médium pauvre en phosphate comme phase stationnaire utilisant une colonne d'échange d'ion enveloppée avec une cellulose DEAE comme matrice et exclusion de taille chromographique utilisant le Sepharcryl S-300HR ...

  1. Granulation of core particles suitable for film coating by agitation fluidized bed I. Optimum formulation for core particles and development of a novel friability test method.

    Science.gov (United States)

    Hamashita, Tomohiro; Nakagawa, Yasuo; Aketo, Takao; Watano, Satoru

    2007-08-01

    To prepare powdered medicines without bitter taste, film coating is required to cover the surface of core particles. In this study, effect of formulation and operating conditions of agitation fluidized bed on the core particle properties was investigated. In order to prevent breakage of the core particles during coating process, which sometimes causes variation of drug dissolution rate, addition of maltose syrup powder during the formulation process of the core particles was investigated. Also, a method for friability test in which the core particles were subjected to strong impact was proposed to evaluate strength of the core particles. The friability of the core particles determined by this test method correlated well with the actual friability of the particles during the coating process. Based on this result, we confirmed this novel friability test method could predict the core particle endurance during the coating process.

  2. 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.)

  3. Degradation of polymers in an alkaline environment

    Energy Technology Data Exchange (ETDEWEB)

    Borges, P. G.; Thorpe, S. J.; Venter, R. D. [Toronto Univ., Toronto, ON (Canada)

    1999-10-01

    To introduce widespread use of hydrogen as a source of fuel, it is essential to significantly reduce the cost of electrolysers and fuel cells, preferably by substituting degradation-resistant low cost alternatives for traditional materials. An experimental apparatus for evaluating short-term degradation characteristics of polymers in 25 per cent potassium hydroxide aqueous solution at 70 and at 85 degrees C was constructed to determine changes in physical appearance, weight, volume and dimensions as a function of immersion time from 0 to 670 hours. Polymers that were part of this test included chlorinated polyvinyl chloride (CPVC), polypropylene (PP),and a polyurethane/polyester blend. Polypropylene demonstrated the greatest degradation resistance to the alkaline environment at both temperatures. CPVC discolored and the polyurethane/polyester blend deteriorated into smaller pieces when subjected to identical conditions. Resistance to degradation in an alkaline environment is a primary requirement for the selection of polymers for use as structural materials in alkaline water analyzers, which in turn is fundamental to the widespread adoption of a hydrogen economy. 6 refs., 13 figs.

  4. Development of thin PdeAg supported membranes for fluidized bed membrane reactors including WGS related gases

    OpenAIRE

    Fernandez, E Ekain; Helmi Siasi Farimani, A Arash; Coenen, KT Kai; Meléndez, J; Viviente, JL; Pacheco Tanaka, DA; Sint Annaland, van, M Martin; Gallucci, F Fausto

    2015-01-01

    This paper reports the preparation, characterization and stability tests of Pd-based thin membranes for fluidized bed membrane reactor applications. Various thin membranes have been prepared by simultaneous Pd-Ag electroless plating. A simple technique for sealing of the produced membranes is reported and discussed. The membranes have been characterized for single gas permeation, and afterwards used for permeation of mixtures of gases and under fluidization conditions. The membranes have show...

  5. FLUIDIZED BED STEAM REFORMER (FBSR) PRODUCT: MONOLITH FORMATION AND CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2006-09-13

    The most important requirement for Hanford's low activity waste (LAW) form for shallow land disposal is the chemical durability of the product. A secondary, but still essential specification, is the compressive strength of the material with regards to the strength of the material under shallow land disposal conditions, e.g. the weight of soil overburden and potential intrusion by future generations, because the term ''near-surface disposal'' indicates disposal in the uppermost portion, or approximately the top 30 meters, of the earth's surface. The THOR{reg_sign} Treatment Technologies (TTT) mineral waste form for LAW is granular in nature because it is formed by Fluidized Bed Steam Reforming (FBSR). As a granular product it has been shown to be as durable as Hanford's LAW glass during testing with ASTM C-1285-02 known as the Product Consistency Test (PCT) and with the Single Pass Flow Through Test (SPFT). Hanford Envelope A and Envelope C simulants both performed well during PCT and SPFT testing and during subsequent performance assessment modeling. This is partially due to the high aluminosilicate content of the mineral product which provides a natural aluminosilicate buffering mechanism that inhibits leaching and is known to occur in naturally occurring aluminosilicate mineral analogs. In order for the TTT Na-Al-Si (NAS) granular mineral product to meet the compressive strength requirements (ASTM C39) for a Hanford waste form, the granular product needs to be made into a monolith or disposed of in High Integrity Containers (HIC's). Additionally, the Hanford intruder scenario for disposal in the Immobilized Low Activity Waste (ILAW) trench is mitigated as there is reduced intruder exposure when a waste form is in a monolithic form. During the preliminary testing of a monolith binder for TTT's FBSR mineral product, four parameters were monitored: (1) waste loading (not optimized for each waste form tested); (2) density

  6. Highly plastic behavior and fluidization of gouge; implications for fault and landslide mechanics and for the generation of mud volcanoes

    Science.gov (United States)

    Shimamoto, Toshihiko; Aoki, Kazuhiro; Seshimo, Kazuyoshi; Hu, Wei; Ma, Shengli; Yao, Lu; Xiong, Ran; Xiao, Yinke

    2016-04-01

    We address an issue on "how low gouge friction can be with an increasing amount of pore fluid" (an unexplored problem in fault mechanics), as studied with a rotary-shear low to high-velocity friction apparatus in Beijing using host specimens of Ti-Al-V alloy with a Teflon sleeve. A friction experiment was conducted on about 1 mm-thick, smectite-rich gouge from Shionohira fault zone, Fukushima, Japan, with 80 wt% of initial pore water, at a normal stress of 1 MPa, and with velocity steps of 17 times ranging in 0.21 microns/s to 2.1 m/s. Friction coefficients at slow rates were initially 0.003 to 0.005 with abundant water, but the coefficients increased to about 0.2 owing to the loss of water during the drained tests. Gouge was squeezed out slowly from host-specimen/Teflon interface as very thin paper-like flakes during a part of the run, indicating highly plastic behavior of gouge. The initial friction was by far the lowest ever reported! A dry high-velocity friction experiment on the same gouge (normal stress 2 MPa, velocity 2.1 m/s) revealed fluidization of gouge due to vaporized water released during decomposition of clay minerals. Friction coefficient increased to its peak (~ 0.8), followed by nearly exponential decay to a steady-state value of ~ 0.2. Then the friction coefficient began to decrease almost linearly with displacement down to ca. 0.07, deviating from an exponential decay. The gouge was lost almost instantly in less than one second, terminating the run. Temperature, measured at the sliding surface, began to decrease at the onset of the nearly linear weakening, strongly suggesting dehydration of clays (endothermic reactions). We interpret the results that steam pressure increased in gouge till a limit to cause a small explosion of gouge. Gouge can fluidize! A series of low to intermediate-velocity experiments on slip-zone materials from Kualiangzi landslide, Sichuan, China, demonstrated that the initial friction coefficient was less than 0.1 with a

  7. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  8. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  9. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  10. Processing Methods of Alkaline Hydrolysate from Rice Husk

    Directory of Open Access Journals (Sweden)

    Olga D. Arefieva

    2017-07-01

    Full Text Available This paper devoted to finding processing methods of alkaline hydrolysate produced from rice husk pre-extraction, and discusses alkaline hydrolysate processing schemed and disengagement of some products: amorphous silica of various quality, alkaline lignin, and water and alkaline extraction polysaccharides. Silica samples were characterized: crude (air-dried, burnt (no preliminary water treatment, washed in distilled water, and washed in distilled water and burnt. Waste water parameters upon the extraction of solids from alkaline hydrolysate dropped a few dozens or thousand times depending on the applied processing method. Color decreased a few thousand times, turbidity was virtually eliminated, chemical oxygen demanded about 20–136 times; polyphenols content might decrease 50% or be virtually eliminated. The most prospective scheme obtained the two following solid products from rice husk alkaline hydrolysate: amorphous silica and alkaline extraction polysaccharide. Chemical oxygen demand of the remaining waste water decreased about 140 times compared to the silica-free solution.

  11. Alkaline and ultrasound assisted alkaline pretreatment for intensification of delignification process from sustainable raw-material.

    Science.gov (United States)

    Subhedar, Preeti B; Gogate, Parag R

    2014-01-01

    Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. The Influence of the Distributor Plate on the Bottom Zone of a Fluidized Bed Approaching the Transition from Bubbling to Turbulent Fluidization

    OpenAIRE

    Paiva, J. M.; Pinho, C.; Figueiredo, R.

    2004-01-01

    The dynamics of the bottom zone of a narrow fluidized bed, from bubbling to turbulent regimes, was studied in a cold model of 0.1 m i.d. and 1.3 m high. Tested distributor types were perforated perspex plates, with six different perforation grids, metallic mesh and porous ceramic, with pressures drops ranging from 0.05 to 350 kPa, corresponding to superficial air velocities from 0.1 to 2.3m s-1. Group B silica ballotini, within the range 0.355-0.425 mm, were used as bed material. The experime...

  13. Wild soybean roots depend on specific transcription factors and oxidation reduction related genesin response to alkaline stress.

    Science.gov (United States)

    DuanMu, Huizi; Wang, Yang; Bai, Xi; Cheng, Shufei; Deyholos, Michael K; Wong, Gane Ka-Shu; Li, Dan; Zhu, Dan; Li, Ran; Yu, Yang; Cao, Lei; Chen, Chao; Zhu, Yanming

    2015-11-01

    Soil alkalinity is an important environmental problem limiting agricultural productivity. Wild soybean (Glycine soja) shows strong alkaline stress tolerance, so it is an ideal plant candidate for studying the molecular mechanisms of alkaline tolerance and identifying alkaline stress-responsive genes. However, limited information is available about G. soja responses to alkaline stress on a genomic scale. Therefore, in the present study, we used RNA sequencing to compare transcript profiles of G. soja root responses to sodium bicarbonate (NaHCO3) at six time points, and a total of 68,138,478 pairs of clean reads were obtained using the Illumina GAIIX. Expression patterns of 46,404 G. soja genes were profiled in all six samples based on RNA-seq data using Cufflinks software. Then, t12 transcription factors from MYB, WRKY, NAC, bZIP, C2H2, HB, and TIFY families and 12 oxidation reduction related genes were chosen and verified to be induced in response to alkaline stress by using quantitative real-time polymerase chain reaction (qRT-PCR). The GO functional annotation analysis showed that besides "transcriptional regulation" and "oxidation reduction," these genes were involved in a variety of processes, such as "binding" and "response to stress." This is the first comprehensive transcriptome profiling analysis of wild soybean root under alkaline stress by RNA sequencing. Our results highlight changes in the gene expression patterns and identify a set of genes induced by NaHCO3 stress. These findings provide a base for the global analyses of G. soja alkaline stress tolerance mechanisms.

  14. Heparin and alkalinized lidocaine versus alkalinized lidocaine for treatment of interstitial cystitis symptoms.

    Science.gov (United States)

    Parsons, C Lowell; Koziol, James A; Proctor, Jeffrey G; Zupkas, Paul; Argade, Sulabha

    2015-04-01

    Interstitial cystitis (IC), sometimes referred to as IC/bladder pain syndrome, is a substantial health care problem. Once considered a rare, orphan disease, it is now believed to be relatively common. This pilot study was undertaken to determine if the combination of heparin and alkalinized lidocaine (heparin-lidocaine) was more efficacious than alkalinized lidocaine at relieving pain and urgency symptoms associated with IC and also capable of yielding higher lidocaine absorption. A single blind study was conducted on 14 IC patients with a heparin-lidocaine combination versus alkalinized lidocaine instilled intravesically. In a separate study serum lidocaine levels for heparin-alkalinized lidocaine combination versus USP lidocaine only were determined by high performance liquid chromatography. Alkalinized lidocaine and heparin have been reported to provide relief from pain and urgency symptoms associated with IC. The heparin-lidocaine combination significantly reduced the % of bladder pain (38% versus 13%, p = 0.029) and urgency (42% versus 8% p = 0.003) compared to lidocaine. In addition the GAR was significantly better for the heparin-lidocaine combination at both 1 hr % improved (77% versus 50%, p = 0.04) and 24 hrs (57% versus 23%, p = 0.002) after study drug treatment. Serum lidocaine levels for the heparin-lidocaine combination were significantly higher compared to USP lidocaine (unalkalinized). The mean +/- SEM was 0.45 +/- 0.09 µg/mL and 0.20 +/- 0.05 µg/mL, respectively (p = 0.019). In this pilot study the heparin-lidocaine combination results in significantly better relief of IC symptoms compared to alkalinized lidocaine and the combination yields higher lidocaine absorption than USP lidocaine.

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Koshkarev Sergey A.

    2017-01-01

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

  17. Using deepest regression method for optimization of fluidized bed granulation on semi-full scale.

    Science.gov (United States)

    Rambali, B; Van Aelst, S; Baert, L; Massart, D L

    2003-06-04

    This study applied the deepest regression method to estimate the granule size of unsuccessful fluidized bed granulation runs. This study uses data from a previous study [Int. J. Pharm. 220 (2001) 149] on optimization of fluidized granulation process, wherein 8 of the 30 runs did not succeeded due to overwetting of the powder bed. The "complete data" (the observed and the estimated granule size by the depth regression method) were used to develop two regression models for the granule size: an empirical model based on the process variables (inlet air temperature, inlet airflow rate, spray rate, and inlet air humidity) and a fundamental model based on the powder bed moisture content and the relative droplet size. The regression models based on the incomplete data from the previous study and the regression models of the "complete data" were comparable in the sense that the contour plots based on the respective models and the predicted granule size were comparable.

  18. Determination of fluidized bed granulation end point using near-infrared spectroscopy and phenomenological analysis.

    Science.gov (United States)

    Findlay, W Paul; Peck, Garnet R; Morris, Kenneth R

    2005-03-01

    Simultaneous real-time monitoring of particle size and moisture content by near-infrared spectroscopy through a window into the bed of a fluidized bed granulator is used to determine the granulation end point. The moisture content and particle size determined by the near-infrared monitor correlates well with off-line moisture content and particle size measurements. The measured particle size is modeled using a population balance approach, and the moisture content is shown to follow accepted models during drying. Given a known formulation, with predefined parameters for peak moisture content, final moisture content, and final granule size, the near-infrared monitoring system can be used to control a fluidized bed granulation by determining when binder addition should be stopped and when drying of the granules is complete. Copyright 2005 Wiley-Liss, Inc. and the American Pharmacists Association.

  19. Modeling Fluid Dynamics and Growth Kinetics in Fluidized Bed Spray Granulation

    Directory of Open Access Journals (Sweden)

    Zhen Li

    2010-12-01

    Full Text Available Fluidized bed spray granulation is used to produce spherical granules from suspensions, solutions and melts. Experimental investigations revealed that fluid dynamics in the granulator plays a crucial role, in particular in the jet. The jet causes the particle movement as well as drop propagation and deposition on the particles. In this work the “Two Fluid Model” (TFM is used to simulate the multiphase fluid dynamics in the fluidized bed. The results of simulations were validated by measuring the particle velocity using Laser Doppler Velocimetry (LDV. From the TFM-simulations with implemented growth mechanisms the growth kinetics is obtained and is used to describe the transient states of various granulation processes by solving the appropriate population balances.

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

    Science.gov (United States)

    Karmakar, M K; Datta, A B

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    H. Jin

    2007-09-01

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

  2. Operating experience and development of fluidized-bed denitrators for UNH at Tokai Reprocessing Plant

    International Nuclear Information System (INIS)

    Sasaki, Minoru; Nakamichi, Hideya; Takeda, Seiichiro; Kubota, Kanya; Katoh, Shuji

    1983-01-01

    The fluidized bed denitrator for uranyl nitrate hexahydrate (UNH) at Tokai reprocessing plant has been operated since 1976. About 170 tons of spent fuel have been reprocessed, and the denitrator has encountered numerous operational problems during the period. This report deals with these technical problems and the associated countermeasures taken, including the dismantling and reconstruction of equipment and the improvement of operating method. The major problems encountered were as follows: (1) the crystallization of UNH on the UNH feeding line, (2) spray nozzle clogging and candle filter clogging, (3) particle growth, (4) plugging of the drawing-out line by nozzle caking, and (5) slugging in fluidized-bed denitration. The total quantity and quality of UO 3 products obtained so far at the plant are also briefly described together with some future R and D programs such as the improvement of UO 3 reactivity and the automation of denitrators. (Aoki, K.)

  3. 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)

  4. Energy extraction from wine dregs by self-sustained burning with fluidized-bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Leu, J.H. [Yu-Da Inst. of Business Technology, Taiwan (China). Dept. of Marketing and Logistics Management; Chung, Y.N.; Pan, T.S.; Chen, C.S. [Dayeh Univ., Taiwan (China). Dept. of Electrical Engineering

    2005-07-01

    Wine dregs typically have moisture contents of between 70 and 80 per cent, and the disposal of wine dregs in Taiwan is both costly and time-consuming. This paper described a method of extracting energy from wine dregs through the use of a pre-drying technique with a fluidized bed technology. A bubble-type fluidized bed combustor was used to combust high moisture Chinese Kaoliang wine lees. The system consisted of an incinerator, a feeding system, a heat recovery system, and an air pollution control system. Results of the experimental study showed that 92.3 per cent combustion was achieved for the wine lees at temperatures of 860 degrees C. Sulfur oxide (SO{sub x}) emissions and nitrogen oxide (NO{sub x}) emissions were negligible. Carbon monoxide (CO) emissions were suppressed to 92 ppm by modulating operating temperatures, axial temperature distributions, and primary and excess air. 3 refs., 3 tabs., 7 figs.

  5. Recovery and separation of iron from iron ore using innovative fluidized magnetization roasting and magnetic separation

    Directory of Open Access Journals (Sweden)

    Yu J.

    2018-01-01

    Full Text Available In this investigation, a pilot-scale fluidized magnetization roasting reactor was introduced and used to enhance magnetic properties of iron ore. Consequently, the effects of roasting temperature, reducing gas CO flow rate, and fluidizing gas N2 flow rate on the magnetization roasting performance were studied. The results indicated that the hematite was almost completely converted into magnetite by a gas mixture of 4 Nm3/h CO and 1 Nm3/h N2 at roasting temperature of 540°C for about 30 s. Under optimized conditions, a high grade concentrate containing 66.84% iron with iron recovery of 91.16% was achieved. The XRD, VSM, and optical microscopy (OM analyses revealed that most of the hematite, except some coarse grains, was selectively converted to magnetite, and that the magnetic properties were greatly enhanced. Thus, their separation from non-magnetic gangue minerals was facilitated.

  6. Beckmann rearrangement of cyclohexanone oxime to {epsilon}-caprolactam using a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Dahlhoff, G.; Hoelderich, W.F. [Technische Hochschule Aachen (Germany)

    1999-07-01

    The application of a fluidized bed reactor on the heterogeneously catalyzed Beckmann rearrangement of cyclohexanone oxime to {epsilon}-caprolactam is presented. For this purpose the classic industrial synthesis route is compared to the new route catalyzed by [B]-MFI zeolite which proved to be the most suitable. To prepare the use of the catalyst the thermodynamics were calculated showing that the residence time of the reactants are of great importance. A regeneration model was developed resulting in a mathematical equation for the regeneration time calculated to seven hours under oxidative conditions. A 40 day regeneration experiment demonstrated the excellent regeneration behaviour of the chosen catalyst showing no decrease in activity after 40 recycle treatments. Finally, the experiments in a constructed non circulating fluidized bed showed good yields and selectivities (99%/91%) completely comparable to the actual synthesis route but avoiding 4 t ammonia sulphate/t product. (orig.)

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    granules is given. This review provides a basis for future mechanistic model development for the drying process of wet granules in pharmaceutical processes. It is intended for a broad audience with a varying level of knowledge on pharmaceutical processes and mathematical modelling. Mathematical models...... particle, can be described using the continuum approach, the pore network modelling method and the shrinkage of the diameter of the wet core approach. As several granules dry at a drying rate dependent on the gas temperature, gas velocity, porosity, etc., the moisture content of a batch of granules......Fluidized bed dryers are frequently used in industrial applications and also in the pharmaceutical industry. The general incentives to develop mechanistic models for pharmaceutical processes are listed, and our vision on how this can particularly be done for fluidized bed drying processes of wet...

  8. A nonlinear model for the fluidization of marine mud by waves

    Energy Technology Data Exchange (ETDEWEB)

    Foda, M.A.; Hunt, J.R.; Chou, Hsien-Ter (Univ. of California, Berkeley (United States))

    1993-04-15

    The authors consider the problem of fluidization of mud deposits in shallow waters due to interactions with water waves. This is of increasing interest because of concerns that water pollutants, including heavy metals, pesticides, etc., are often found near surfaces of mud deposits. The authors look at the question of whether the cohesive properties of mud deposits exhibit nonlinear properties when they experience strains from water wave interactions. It is obvious that with large enough wave interactions the deposits become fluidized, and are not in that case truly nonlinear. In their modeling efforts they try to incorporate these ideas into a cohesive model where the magnitude of the water wave-sediment interaction has an influence on the type of response within the system.

  9. SPECIFIC FEATURES OF THE OXYFUEL COMBUSTION CONDITIONS IN A BUBBLING FLUIDIZED BED

    Directory of Open Access Journals (Sweden)

    Pavel Skopec

    2016-08-01

    Full Text Available Oxyfuel combustion is a promising approach for capturing CO2 from power plants. This technology produces a flue gas with a high concentration of CO2. Our paper presents a verification of the oxyfuel combustion conditions in a bubbling fluidized bed combustor. It presents a theoretical analysis of oxyfuel combustion and makes a comparison with combustion using air. It is important to establish a proper methodology for stoichiometric calculations and for computing the basic characteristic fluidization properties. The methodology presented here has been developed for general purposes, and can be applied to calculations for combustion with air and with oxygen-enriched air, and also for full oxyfuel conditions. With this methodology, we can include any water vapour condensation during recirculation of the flue gas when dry flue gas recirculation is used. The paper contains calculations for a lignite coal, which is taken as a reference fuel for future research and for the experiments.

  10. Preliminary market assessment of fluidized-bed waste-heat recovery technology

    Energy Technology Data Exchange (ETDEWEB)

    Campos, F.T.; Fey, C.L.; Grogan, P.J.; Klein, N.P.

    1980-06-01

    A preliminary assessment of fluidized-bed waste-heat recovery (FBWHR) system market potential is presented with emphasis on the factors influencing industrial acceptability. Preliminary market potential areas are identified based on the availability of waste heat. Trends in energy use are examined to see the effect they might have on these market potential areas in the future. Focus groups interviews are used to explore important factors in the industrial decision-making process. These important factors are explored quantitatively in a survey of industrial plant engineers. The survey deals with the waste-heat boiler configuration of the FBWHR system. Results indicate market acceptance of the fluidized-bed waste-heat boiler could be quite low.

  11. Improved steam gasification of lignocellulosic residues in a fluidized bed with commercial steam reforming catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Aznar, M.P.; Corella, J.; Delgado, J.; Lahoz, J. (Univ. of Zaragoza (Spain))

    1993-01-01

    The improved/two-stage steam gasification of biomass or lignocellulosic residues in fluidized bed with steam reforming catalysts placed in a downstream secondary reactor has been studied. Two commercial catalysts, R-67 and RKS-1 from Topsoee, were used at their incipient fluidization conditions. At 720-760 C and space-times of only 0.10-0.20 s, with catalyst sizes under 1.0 mm and with steam/biomass ratios of 1.2-1.6, tar conversions of 99.95% were achieved in the catalytic reactor. In this process, tar and methane in the flue gas can be easily lowered below 5 mg/m[sup 3](NTP) and 0.5 vol %, respectively, without using oxygen. The catalyst deactivation by coke from the tar cracking is the main problem of this process.

  12. Simultaneous determination of devolatilization and char burnout times during fluidized bed combustion of coal

    International Nuclear Information System (INIS)

    Christofiedes, N.; Brown, R.C.

    1992-01-01

    In this paper, the authors investigate a method for simultaneous determination of devolatilization and char burnout times based on the analysis of CO 2 emissions from a fluidized bed combustor. The technique is non-intrusive and can be performed under realistic combustion conditions. The authors' method involves batching single-size coal samples in a fluidized bed combustor that is heated with propane gas or other fuel. Carbon dioxide profiles versus time for the batch tests are analyzed with a linear model to obtain characteristic time constants for coal devolatilization and char combustion which can be related to total devolatilization time and burnout time for a coal sample. The authors' approach does not require special sample preparation, can be performed in actual combustion equipment and employs standard boiler instrumentation

  13. Performance of Fluidized bed Fenton process in Degrading Acid Blue 113

    Science.gov (United States)

    Bello, M. M.; Raman, A. A.

    2017-06-01

    The performance of a fluidized bed Fenton process in degrading Acid Blue 113 (AB 113) was investigated. Fluidized bed Fenton process is a modification of conventional Fenton oxidation, aimed at reducing sludge generation and improving process performance. Response surface methodology was used to study the effects of operational parameter on the color removal from the dye. Dimensionless factors, Dye/Fe2+, H2O2/Fe2+ and pH were used as the independent variables in Box-Behnken Design (BDD). Reduced quadratic model was developed to predict the color removal. The process could remove up to 99 % of the initial color. The most significant factor for color removal was found to be Dye/Fe2+, followed by H2O2/Fe2+. Unlike conventional Fenton, the initial pH of the solution does not have a significant effect on the color removal.

  14. Using of fluidized-bed jet mill to a super fine comminution of steel composite

    Directory of Open Access Journals (Sweden)

    D. Urbaniak

    2015-01-01

    Full Text Available In many industries the demand for very fine material increases. In the metallurgical industry, for example, there is increasing use of the production of high density metal elements with the use of metallurgical powder composites. The use of powder composites requires prior their grinding. Unfortunately, the very fine grinding is not an easy process. The using for this purpose fluidized-bed jet mill was proposed in the paper. The attempts of grinding of metallurgical powder were carried out in the fluidized-bed jet mill. After the experiment analyses of particle size distribution of grinding products were performed. The results are presented in graphs. Analyses of the obtained results concluded that the grinding of very fine metallurgical composite is possible and produces positive results.

  15. N2 O A greenhouse gas released from the combustion of coals in fluidized beds

    International Nuclear Information System (INIS)

    Boavida, D.; Lobo, L. S.; Gulyurtlu, I.; Cabrita, I.

    1996-01-01

    This paper discusses the results of the experimental work investigating the formation of N-2 O and NO during fluidized bed combustion of coals, and of chars and volatiles produced from the pyrolysis of these coals. Ammonia (N H 3 ) and hydrogen cyanide (HCN) are shown to play important roles as gas phase precursors of both NO and N 2 O. The conversion of fuel-N through N H 3 and HCN to N 2 O and NO was studied using a fluidized bed combustor in the temperature range between 973 K and 1273 K, for two different coals. The results suggest that the principal contribution to N 2 O emission Originated from volatile-N, however, char-N could also have an important role, depending upon the temperature. 1 fig., 8 tabs

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

    Directory of Open Access Journals (Sweden)

    IVANA PERNA

    2011-03-01

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

  17. Temperature Dependence of Mineral Solubility in Water. Part 2. Alkaline and Alkaline Earth Bromides

    Science.gov (United States)

    Krumgalz, B. S.

    2018-03-01

    Databases of alkaline and alkaline earth bromide solubilities in water at various temperatures were created using experimental data from publications over about the last two centuries. Statistical critical evaluation of the created databases was produced since there were enough independent data sources to justify such evaluation. The reliable experimental data were adequately described by polynomial expressions over various temperature ranges. Using the Pitzer approach for ionic activity and osmotic coefficients, the thermodynamic solubility products for the discussed bromide minerals have been calculated at various temperature intervals and also represented by polynomial expressions.

  18. Net alkalinity and net acidity 2: Practical considerations

    Science.gov (United States)

    Kirby, C.S.; Cravotta, C.A.

    2005-01-01

    The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH mine drainage treatment can lead to systems with insufficient Alkalinity to neutralize metal and H+ acidity and is not recommended. The use of net alkalinity = -Hot Acidity titration is recommended for the planning of mine drainage treatment. The use of net alkalinity = (Alkalinitymeasured - Aciditycalculated) is recommended with some cautions

  19. A comparison of solute migration in a test granulation dried by fluidization and other methods.

    Science.gov (United States)

    Travers, D N

    1975-07-01

    The intragranular migration of sodium chloride in granules made by the wet massing of heavy kaolin B.P. with salt solution has been studied in batches dried by fluidization and a vacuum tumbling method. The larger granules from the fluidized batch exhibited considerable intragranular variation with the outer crust containing over twice the average salt concentration. Solute loss from this layer by abrasion on prolonged fluidization was slight but the dust eluted from the dryer had a salt content above average. Analysis of sieved fractions of the dust showed that this enrichment was concentrated in the fine material passing a 53 mum mesh. The vacuum dried granules had less migration and were less resistant to crushing than those dried by fluidization. The dust produced had a salt content only slightly greater than the average composition and the overall solute content of the sized fractions were all close to this average. The same system was used to study intergranular migration in a fixed bed when the granules were dried by infrared radiation, by microwave radiation, by convection from air and in a vacuum. The greatest migration occurred in samples dried by infrared radiation and the maximum solute concentration was near the middle of the bed. The air dried granules had less migration and the maximum concentration was in the surface layer. The granules dried in a vacuum and by microwave radiation were fairly uniform in composition throughout the bed. The above results are explained on the basis of the capillary theory of drying together with the modifying influence of the drying method on the probable heat and mass transfer rates.

  20. Experimental heat transfer coefficients between a surface and fixed and fluidized beds with PCM

    OpenAIRE

    Izquierdo-Barrientos, María Asunción; Sobrino, Celia; Almendros-Ibáñez, José Antonio

    2015-01-01

    This work presents an experimental study to determine the capacity of a phase change material (PCM) in granular form to be used in fixed and bubbling fluidized beds for thermal energy storage. The experimental measurements are focused on determination of the heat transfer coefficient between a heated surface immersed in the bed and the granular PCM. The flow rate is varied to quantify its influence on the heat transfer coefficient. The PCM used is Rubitherm GR50 with a phase change tem...