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Home>Products>Journal and Reviews>I.RE.Ch.E.>Latest issue
International Review of Chemical Engineering (Rapid Communications) - September 2009 - Papers
International Review of Chemical Engineering (Rapid Communications) - Papers
by Jorge F. Gabitto, Costas Tsouris Vol. 1. n. 5, pp. 394-411
Abstract - Many industrial chemical processes attempt to produce inexpensive purified hydrogen for use in industrial applications and in fuel cell power systems. Hydrogen-permeable metal membranes made of palladium and its alloys are the most widely used for hydrogen separation due to their high hydrogen permeability and their ideally infinite hydrogen selectivity. However, sulfur poisoning has been found to have negative effects on the performance of these materials. The goal of this paper is to present experimental and theoretical information that has been published in the open literature on the mechanism of sulfur poisoning of palladium membranes. Studies based upon the reduction mechanism of transition metals have been included when relevant to the subject of this work. The collected information has been critically reviewed and conclusions drawn. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Hydrogen, Palladium membranes, Sulfur poisoning.
Vol. 1. n. 5, pp. 411-418
Abstract - Different
treatment techniques; based on physical, chemical or biological
processes, are used in the removal of organic pollutants from wastewater
streams. One of the widely used physical processes is the adsorption
process using activated carbon. A modified process utilizing a combined
activated carbon-clay mixture was adopted in the present study providing
improved efficiency. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Wastewater treatment, Activated clay treatments, Acid and alkali activated clay, Organic waste adsorption, Molasses removal.
Vol. 1. n. 5, pp. 419-427
Abstract - The objective of this paper is to predict the chemical and hydraulic behaviour of the pulping digester under hazardous conditions which include the channelling phenomenon. The pulping digester was modelled using the CFD, finite volume method in FLUENT, including the channelling phenomenon and chemical reactions in the channel. A 2D geometry of the digester was built and symmetric planes were defined in Gambit. The mesh was then exported to the FLUENT and the geometry was treated with the axisymmetric function to establish a complete model of the digester. The Eulerian scheme was applied to represent the multiphase flows in the digester. A heterogeneous porous media was defined for the compressible bed. Species transport was applied to define a mixture template of the wood chips components. The Kappa number was predicted in and around the channel to characterize how cooking develops under hazardous conditions. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Pulping digester, Channelling, Mass transfer, Lignin, Chemical reaction, Porous media, Multiphase, Axisymmetric.
Vol. 1. n. 5, pp. 428-438
Abstract - This article aims to address the issue of simulating plasma-jet by using an innovative computational approach namely the Lattice Boltzmann Method (LBM) from the point of view of extending the applications to simulating flows with temperature-dependent physical parameters. The work focuses on the phenomena occurring in plasma-jet that define the link between LBM lattice and physical lattice. High temperature dependence of the plasma parameters is considered. Argon characteristics fall into this category. This gas is one of the most ones used in plasma spraying. Complex thermal plasma jet phenomena and basis of classical methods in CFD (discretisation, stability condition, modeling…), in one side, and the simple scheme of the Boltzmann equation which is particularly adopted for simulating gases flows, in the other side, give us the possibility of taking out the dynamic and thermal characteristics of this complex flow. An important section on validation of this model includes details of available reference results is presented and discussed. It focuses mainly on the validation of our results with previous numerical and experimental results based on the centerline temperature and velocity profiles, its distributions over the computational domain and eventually the effect of the computational domain size. The jet width, the Gaussian radial profiles and the effects of inlet quantities are analyzed. A real spraying configuration is also examined. The quality of the results shows a great efficiency for the lattice Boltzmann method. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Lattice Boltzmann Method, Modeling and simulation, Plasma jet, Temperature-dependent diffusion parameters.
Vol. 1. n. 5, pp. 439-444
Abstract - This study investigates pressure loss in pipe bends at a novel combination of conditions - large pipe curvature and high Re. Detailed measurements of pressure drop, including measurements on the inside and outside of the pipe bend, are made over a range of high Reynolds numbers (> 3 x 105). Under these conditions, upstream effects are much more pronounced than in previous investigations, and correlations for pressure drop in pipe bends significantly underpredict the measured pressure loss. The effect of two downstream exit configurations is also studied. The downstream exit configuration does not influence the pressure drop behavior upstream of the pipe bend, but leads to significant variations throughout the pipe bend. In all cases, wall friction is the dominant factor contributing to pressure loss in the bend. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: High Re, Pipe Bends, Pressure Loss.
Abstract - Here we provide a brief overview on smart materials, products and systems, from smart materials and their classification up to structured systems. We present a brief revision of smart building solutions and their combination of those creating a tendency towards buildings that may be considered smart as a whole. Also, of current smart solutions that respond to the environment, and whose smartness resides in the design of the systems along with the selection of adequate materials. The buildings’ skins, for example, are configured in such a way that they respond to the environment. To conclude, we will make a proposal on applications in the shape of charts of materials, products and systems for architecture and construction. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Smart materials, Products and systems, Smart materials applied to architecture and construction, Smart architectures.
Vol. 1. n. 5, pp. 453-459
Abstract - The values of effective diffusivity for the transport of water vapor through the dried cake during freeze-drying of tomato tree fruit juice (TTF juice) have been determined by two methods: i) from the drying curve of frozen fruit juice in a pilot dryer, and ii) by the receding surface of the sublimation front during drying in a freeze-drying microscope (FDM). The moisture diffusivity data obtained by the freeze-drying curves and the freeze-drying microscope data are almost close but the FDM procedure is faster. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Water Diffusivity Measurements, (Cyphomandra betacea (Cav ) Send).
Vol. 1. n. 5, pp. 460-466
Abstract - The viscoelastic properties of fungal treated starches were studied by Dynamic Mechanical Thermal Analysis in the tensile mode. Native starch was used as control. Modified starches were produced by fermentation with isolates of the fungus Ophiostoma. Overall, the storage modulus was higher in modified starches. The glass transition temperature determined by tan peak of native starches occurred at ~80°C, but treated starches displayed three different thermal transitions at ~70, 80, and a broad shoulder at 120°C. Results obtained from solid state NMR, FTIR, and chromatography suggest that the functional properties of modified starches can be attributed either to the presence of extracellular exo-polysaccharides or intermolecular bonds occurring at the C6 in the glucopyranose ring. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Fungal exopolysaccharides, Ophiostoma spp., Starch-like polymers, Viscoelastic and chemical properties of starch.
Vol. 1. n. 5, pp. 467-473
Abstract - Three-dimensional gas-liquid simulations in a cylindrical bubble column with an external loop were performed. The effects of two types of gas inlet and a liquid phase external loop recirculation were evaluated. Results were compared with experimental data found in the literature for three different gas inlet velocities. The drag force was modeled using the Ishii-Zuber model, the k-epsilon turbulence model was applied only for the continuous phase and the dispersed one was considered laminar. Lift, Magnus and added mass forces were neglected. Good agreement of the time-averaged gas holdup profile with experimental data available in the literature was obtained. It was found that three dimensional simulation approach used in this work was able to capture the complex transient fluid dynamics in bubbly flows. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: CFD, Bubble Columns, Different Inlets.
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