Experimental Investigation of 3D Velocity by Tomographic Particle Image Velocimetry (Tomo-PIV) in a Short Riser Section

AbstractThe measurement of instantaneous velocity field with high spatial resolution makes the Tomo-PIV (tomographic particle image velocimetry) technique attractive for the study of complex flows in circulating beds. The Tomo-PIV technique is employed for obtaining the velocity field of the fluid phase in three dimensions using tracer particles which follow the fluid. They are immersed in the fluid and illuminated by a source of pulsed light (laser) within a three-dimensional region. Images of the particles are recorded in the focus of several viewing directions using CCD (Charge-Coupled Device) sensors. The distribution of light intensity is discretized into a 3D array of voxels and then analyzed by interrogation of cross-correlation in three dimensions. The information field is returned in the form of instantaneous velocities of the measurement volume. This paper aims to present an experimental setup for an initial investigation of the velocity field of the particulate phase of a riser section of a circulating bed. The calibration errors were between 0.209 and 0.066 pixels and after the self-calibration errors were below 0.097 pixels. The volume investigated was 82 x 100 x 10 mm3 with a resolution of 1571 x 897 x 113 voxels. The reconstructed volumes were processed using 3D cross-correlation with a volume interrogation size of 110 voxels decreasing to a final size of 16 voxels with a 75% overlap between adjacent interrogation volumes. The velocity field produced has 224 x 393 x 28 voxels

Comparison Of Downer And Riser Flows In A Circulating Bed By Means Of Optical Fiber Probe Signals Measurements

In this work, the riser (2.42 m high) and downer (0,85 m high) sections with an ID of 82 mm in both, were analyzed to study the temporal fluid dynamics properties of a circulating bed system in terms of electrical signals of particles concentration obtained by an optical fiber probe. Experiments were conducted using ambient air as the fluid phase and FCC (fluid catalytic cracking) particles as the solid phase. The measurements with the optical fiber probe were conducted in the inlet and outlet zones of both riser and downer. Signals were evaluated in the phase space (chaos analysis), by reconstructing the attractors and calculating the Kolmogorov entropy and the correlation dimension. Results show that the downer presents a less chaotic flow, with lower values of Kolmogorov entropy and correlation dimension, compared to the riser. In the entrance of the downer, the flow is less complex and more predictable in the center due to the effect of the solid feeder. The flow develops in direction of the exit zone and at that position there is no much difference in complexity between the central and wall. In the case of the riser, at the entrance effect is caused by a question of configuration, due to a presence of a curve, making the solid concentration increase toward the wall. In the exit zone, the flow suffers the effect of the abrupt exit. © 2012 Published by Elsevier Ltd.42295302Manyelle, S.V., Zhu, J.X., Khayat, R.E., Pärssinen, J.H., Analysis of the chaotic dynamics of a high-flux CFB riser using solids concentration measurements (2006) China Particuology, 4, pp. 136-146Zhang, H., Huang, W.X., Zhu, J.X., Gas-solids flow behavior: CFB riser vs. Downer (2001) AIChE Journal, 47, pp. 2000-2011Zhu, J.X., Yu, X.Q., Jin, Y.Y., Grace, J.R., Issangya, A.S., Cocurrent downflow circulating fluidized bed reactor A state of art review (1005) Can J Chem Eng, 73, pp. 667-677Zhu, J., Yan, A., Scale-up effect of riser reactors (1): Axial and radial solids concentration distribution and flow development (2004) Ind Eng Chem Res, 43, pp. 5810-5819Broomhead, D.S., King, G.P., Extracting qualitative dynamics from experimental data (1986) Physica 20D, pp. 217-236Schouten, J.C., Takens, F., Van Den Bleek, C.M., Estimation of the dimension of a noisy attractor (1994) Phys Rev e, 50, pp. 1851-1961Schouten, J.C., Takens, F., Van Den Bleek, C.M., Maximum likelihood estimation of the entropy of an attractor (1994) Phys Rev e, 49, pp. 126-129Manyele, S.V., Zhu, J., Zhang, H., Analysis of the microscopic flow Structure of a CFB downer reactor using solids concentration signals (2003) Int J Chem React Eng, 1, pp. A55Cheng, Y., Wei, F., Lin, Q., Jin, Y., A comparison of local chaotic behaviors in a riser and a downer (1998) Fluidization IX, pp. 613-620. , L.-S. Fan and T.M. Knowlton, editors, New York: Engineering Foundatio

Concurrent Moving Bed Model Applyed In Cyclones, Part Ii: Simultaneous Heat And Mass Transfer In Convective Drying [aplicação Do Modelo Do Leito Deslizante E Escoamento Concorrente Para Ciclones, Parte Ii: Transferência Simultânea De Calor E De Massa Na Secagem Convectiva]

The basic characteristic of the rough particle flow in the cyclone is 100% of collection efficiency. This phenomenon occurs because as soon as particles enter the equipment they go to the cyclone wall and move downward to the hopper. In this case, the gas-particle heat and mass transfer occur basically close to cyclone wall, with same concurrent movement Due to this fluid dynamics description, it is proposed in this paper a model to heat and mass transfer during the rough rice drying in cyclones based on concurrent movement model. The model results are compared with the ones obtained experimentally in two Lapple cyclones using rough rice as test material. It was observed a good agreement between experimental and model results of air temperature and humidity as well rice grains temperature and moisture content.101899

Isomerization Of Essential Oil Of (piper Hispidinervium) C. Dc To Obtain Isosafrole [isomerização Do óleo Essencial De Pimenta-longa (piper Hispidinervium C. Dc) Para A Obtenção De Isosafrol]

The Brazilian peppers present proprieties that can be used in fragrance and pharmaceutical industries, for example. One these pepper is long pepper (Piper hispidinervium C. DC.), who its essential oil is rich in safrole. Safrole is an important compound with application in several industries, such as pharmaceutics, cosmetics. After its chemical conversion, for example, it is possible to obtain heliotropin, a fixative agent for fragrances. The sequence to obtain the heliotropin is by safrole isomerization, that, initially, produce isosafrole. In this work, however, presents the synthesis of isosafrole directly from essential oil of Piper hispidinervium C. DC. In this case, the isomerization of essential oil was done getting 79,4 % of cis, trans-isosafrole mixture. The essential oil presented 86,4 % of safrole, resulting in 97,1 % yield to cis, trans-isosafrole.404737740Alécio, A.C., Bolzani, V.S., Young, M.C.M., Kato, M.J., Furlan, M., Antifungal amide from leaves of Piper hispidum (1998) Journal of Natural Products, 61, pp. 637-639Baldoqui, D.C., Kato, M.J., Cavalheiro, A.J., Bolzani, V.S., Young, M.C.M., Furlan, M., New chromene and prenylated benzoic acid from Piper aduncum (1999) Phytochemistry, 51, pp. 899-902Barreiro, E.J., Fraga, C.A.M., The utilization of safrole, principal chemical constituent of sassafras oil, in the synthesis of compounds actives in the arachidonic acid cascade: Antiinflammatory, analgesic and antithrombotic (1999) Química Nova, 22 (5), pp. 744-759Benevides, P.J.C., Sartorelli, P., Kato, M.J., Phenylpropanoids e neolignanas from Piper regnellii (1999) Phytochemistry, 52, pp. 339-343Bauer, K., Garbe, D., Surberg, H., (2002) Flavors and fragrances, Ullmann Encyclopedia of industrial Chemistry, , Electronic Release, 6th, EdCiccio, J.F., Ballestero, C.M., Volatile components of Piper aduncum (Piperaceae) leaves and spikes from Costa Rica (1997) Revista de Biologia Tropical, 45, pp. 783-790Costa, C.M.L., (1999) Influence of drying condition on yield and composition of long pepper (Piper hispidinervium C. DC.) essential oil, p. 214. , Dissertação de Mestrado, Departamento de Engenharia Química, Universidade Federal do Pará, Belém, Pará. (in Portuguese, with abstract in English)Lago, J.H.G., Ramos, C.S., Casanova, D.C.C., Morandim, A.A., Bergamo, D.C.B., Cavalheiro, A.J., Bolzani, V.S., Kato, M.J., Benzoic acid derivatives from Piperspecies and their fungitoxic activity against Cladosporium cladosporioides and C. sphaerospermum (2004) Journal of Natural Product, 67, pp. 1783-1788Maia, J.G.S., Silva, M.L., Luz, A.I.R., Zoghbi, M.G.B., Ramos, L.S., Pipper species from Amazon richies in safrole (1987) Química Nova, 10 (3), pp. 200-204Moreira, D.D., Guimarães, E.F., Kaplan, M.A.C., A chromene from Piper aduncum (1998) Phytochemistry, 48, pp. 1075-1077Navickiene, H.M.D., Alécio, A.C., Kato, M.J., Bolzani, V.S., Young, M.C.M., Cavalheiro, A.J., Furlan, M., Antifungal amides from Piper hispidum and Piper tuberculatum (2000) Phytochemistry, 55, pp. 621-626Santos, A.S., Pereira Jr., N., Silva, I.M., Sarquis, M.I.M., Antunes, O.A.C., Peroxidase catalyzed microbiological oxidation of isosafrol into piperonal (2004) Process Biochemistry, 39, pp. 2269-227

Thermogravimetric Analysis Of Long Pepper (piper Hispidinervium C.dc.) Essential Oil [análise Termogravimétrica Do óleo Essencial De Pimenta Longa (piper Hispidinervium C. Dc)]

Long pepper (Piper hispidinervium C. DC.) is a shrub found in the Amazon region, which supplies an essential oil rich in safrole. Normally, long pepper essential oil is commercialized in natura, which makes its processing a fundamental step in scientific and technological investigation. An important step of safrole commercialization is the separation of essential oil by, for example, a distillation process. In such a case it is important to know some thermodynamics parameters, such as energy of activation and enthalpy of vaporization. The present study was aimed at applying the kinetic of zero order evaporation process for the essential oil of P. hispidinervum by thermogravimetric analysis. The thermal analysis data were utilized to determine the energy of activation and enthalpy of vaporization, which resulted in the values 41.11 kJ.mol-1 and 43.73 kJ.mol-1, respectively.412275278Hazra, A., Dollimore, D., Alexander, K., Thermal analysis of the evaporation of compounds used in aromatherapy using thermogravimetry (2002) Thermochimica Acta, 392, pp. 221-229Hazra, A., Alexander, K., Dollimore, D., Riga, A., Characterization of some essential oils and their key components (2004) Journal of Thermal Analysis and Calorimetry, 75, pp. 317-330Leiva, R.R.C., Crnkovic, P.M., Santos, A.M., O emprego da termogravimetria para determinar a energia de ativação do processo de combustão em óleos combustíveis (2006) Química Nova, 29 (5), pp. 940-946Nascimento, F.R., Cardoso, M.G., Souza, P.E., Lima, R.K., Salgado, A.P.S., Guimarães, Efeito do óleo essencial de pimento longa (Piper hispidinervum C. DC) e do Emulsificante Tween® 80 sobre o crescimento micelial de Alternaria alternata (Fungi: Hyphomycetes) (2008) Acta Amazonica, 38 (3), pp. 503-508Navickiene, H.M.D., Alécio, A.C., Kato, M.J., Bolzani, V.S., Young, M.C.M., Cavalheiro, A.J., Furlan, M., Antifungal amides from Piper hispidum and Piper tuberculatum (2000) Phytochemistry, 55 (6), pp. 621-626Price, D.M., Hawkins, M., Calorimetry of two disperse dyes using thermogravimetry (1998) Thermochimica Acta, 315, pp. 19-24Silva, E.C., Paola, M.V.R.V., Matos, J.R., Análise térmica aplicada à cosmetologia (2007) Revista Brasileira De Ciências Farmacêuticas, 43 (3), pp. 347-356Zacaroni, L.M., Cardoso, M.G., Souza, P.E., Pimentel, F.A., Guimarães, L.G., Salgado, A.P.P., Potencial fungitóxico do óleo essencial de Piper hispidinervum (pimenta longa) sobre os fungos fitopatogênicos Bipolaris sorokiniana, Fusarium oxysporum e Colletotrichum gloeosporioides (2009) Acta Amazonica, 39 (1), pp. 193-19

Reaction Of Dissolved Ozone In Hydrogen Peroxide Produced During Ozonization Of An Alkaline Medium In A Bubble Column [avaliação Do Efeito Da Reação De Ozônio Dissolvido Com Peróxido De Hidrogênio Gerado Durante A Ozonização De Meio Alcalino Em Uma Coluna De Borbulhamento]

The effect of a reaction of dissolved ozone in an alkaline water solution with hydrogen peroxide was evaluated. Assays were conducted in a bubble column with a gaseous ozone concentration (mixed with oxygen) at 21 and 27 g m-3. Concentration curve of dissolved ozone in the liquid revealed an ozone concentration peak in the liquid phase, subsequent decreasing concentration and constant maintenance in the stationary phase. Highest concentration was not detected for the lowest ozone concentration in the gaseous phase. Peak was due to the self-decomposition of ozone in the liquid phase and the production of hydrogen peroxide. The latter reacted with molecular dissolved ozone and decreased ozone concentration after maximum concentration.3618185Bin, A.K., Duczmal, B., Machniewski, P., Hydrodynamics and ozone mass transfer in a tall bubble column (2001) Chemical Engineering Science, 56 (21-22), pp. 6233-6240Cheng, J., Yang, Z.R., Chen, H.Q., Kuo, C.H., Zappi, M.E., Simultaneous prediction of chemical mass transfer coefficients and rates for removal of organic pollutants in ozone absorption in an agitated semi-batch reactor (2003) Separation and Purification Technology, 31 (1), pp. 97-104Glaze, W.H., Reaction products of ozone: A review (1986) Environmental Health Perspectives, 69, pp. 151-157Kunz, A., Zamora, P.P., Moraes, S.G., Durán, N., Novas tendências no tratamento de efluentes têxteis (2002) Química Nova, 25 (1), pp. 78-82Langlais, B., Reckhow, D.A., Brink, D.R., (1991) Ozone in water treatment: Application and engineering, , Chelsea: Lewis Publishers IncLegrini, O., Oliveros, E., Braun, A.M., Photochemical processes for water treatment (1993) Chemical Reviews, 93 (2), pp. 671-678Lin, S.H., Yeh, K., L. Looking to treat wastewater? Try ozone (1993) Chemical Engineering Science, 100 (5), pp. 112-116Lucas, M.S., Peres, J.A., Lan, B.Y., Li Puma, G., Ozonation kinetics of winery wastewater in a pilot-scale Hubble column reactor (2009) Water Research, 43 (46), pp. 1523-1532Von Gunten, U., Ozonation of drinking water: Part I. Oxidation kinetics and product formation (2003) Water Research, 37 (7), pp. 1443-146

Concurrent Moving Bed Model Applyed In Cyclones, Part I: Gas-particle Heat Transfer [aplicação Do Modelo Do Leito Deslizante E Escoamento Concorrente Para Ciclones, Parte I: Transferência De Calor Gás-partícula]

The basic characteristic of the rough particle flow in the cyclone is 100% of collection efficiency. This phenomenon occurs because as soon as particles enter the equipment they go to the cyclone wall and move downward to the hopper. In this case, the gas-particle heat transfer occurs basically close to cyclone wall, with same concurrent movement. Due to this fluid dynamics description, it is proposed in this paper a model to gas-particle heat transfer in cyclones based on concurrent moving bed model. The model results are compared with the ones obtained experimentally in two Lapple cyclones, using two different particles with different size. It was observed a good agreement between experimental and model results of outlet air and particle temperatures.101848

A design and study of the effects of selectivity on binary separation in a four-zone simulated moving bed for systems with linear isotherms

The simulated moving bed (SMB) is potentially an economical method for the separation and purification of natural products because it is a continuous processes and can achieve higher productivity, higher product recovery, and higher purity than batch chromatographic processes. Despite the advantages of SMB, one of the challenges is to specify its zone flow rates and switching time. In this case it is possible to use the standing wave analysis. In this method, in a binary system, when certain concentration waves are confined to specific zones, high product purity and yield can be assured. Appropriate zone flow rates, zone lengths and step time are chosen to achieve standing waves. In this study the effects of selectivity on yield, throughput, solvent consumption, port switching time, and product purity for a binary system are analyzed. The results show that for a given selectivity the maximum throughput decreases with increasing yield, while solvent consumption and port switching time increase with increasing yield. To achieve the same purity and yield, a system with higher selectivity has a higher throughput and lower solvent consumption