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International Review of Chemical Engineering (Rapid Communications) - July 2010 - Papers

 

 

   

 

 

 

International Review of Chemical Engineering (Rapid Communications) - Papers

 

go to top   Modeling of Clay Paste Extrusion Through a Rectangular Die
         by Fernando A. Andrade, Hazim A. Al-Qureshi, Dachamir Hotza

        Vol. 2. n. 4, pp. 478-483

 

Abstract - An important aspect of clay paste extrusion is the pressure as a function of extruded velocity/distance traveled. Therefore, the present theory concentrates on deriving basic equations that control the clay paste flow behavior of rectangular extrusion process during the steady-state flow. The main parameters which control the extrusion pressure are the effective stress in compression of the clay paste, the geometry of extrusion tools and billet, operational conditions and the coefficients of friction between the barrel and the die land surfaces. The theoretical extrusion pressure results were analyzed and discussed thoroughly. Finally, it can be concluded that the present theoretical analysis serves to place the present approach in the context of work on other extrudable materials of different geometry. In addition, it can be used as an effective tool for evaluating and obtaining clay paste materials with optimized properties for extrusion process in the ceramic industry.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Clay, Extrusion, Materials Processing, Mathematical Modeling, Paste, Unit Operations.

 


 

go to top   Analysis of Irradiator Tube Purging for Fiber Drawing
         by Showkat J. Chowdhury, Tyler Kirby

        Vol. 2. n. 4, pp. 484-493

 

Abstract - This paper presents the numerical and experimental investigation of fluid flow and mass transfer in an irradiator tube. After applying the synthetic coating material for cushioning and protection, optical fibers or wires are drawn through a glass tube where UV light from the surrounding irradiators cause curing of the coating material. During this curing process, fumes are generated, which needs to be flushed out of the tube before it diffuses to the glass wall and causes tube smoking, a problem faced by the industries. Analytical calculations are first done to study the effect of laminar and turbulent flow, flow rate and tube diameter. Numerical simulation for the purging air flow and mass transfer of the generated chemical species is then done using a computational model and results presented. Irradiator tube flows with regular and enhanced lip at exit and without lip are all simulated. The mass concentration of generated species near the tube wall is found high for regular and extended lip (causes tube smoking), but low for no lip (suggests no smoking and hence desirable). Computations are also done for larger tube diameter, which gives lowest species concentration. Experiments are performed and they support the simulated results.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Fiber Coating, Irradiator Tube, Turbulence, Mass Diffusion, Tube Smoking, Numerical Analysis.

 


 

go to top   Removal of Copper (II) from Aqueous Solutions with Activated Carbon Obtained by Chemical Activation of Orange Peel
         by Liliana Giraldo, Juan Carlos. Moreno-Piraján

        Vol. 2. n. 4, pp. 494-502

 

Abstract - Activated carbons (ACs) were prepared by pyrolysis of orange peel in the presence of zinc chloride (ZnCl2) (chemical activation). Orange peel from the Colombian orange cultivar was impregnated with aqueous solutions of ZnCl2 following a variation of the incipient wetness method. Different concentrations were used to produce impregnation ratios of 40, 70, 110 and 160 wt%. Activation was carried out under an argon flow at a temperature of 823 K with a 4 h soaking time. The porous texture of the obtained ACs was characterized by physical adsorptions of N2 at 77 K and CO2 at 273 K. The impregnation ratio had a strong influence on the pore structure of these ACs, which could be easily controlled by simply varying the proportion of ZnCl2 used in the activation. Thus, a low impregnation ratio led to essentially microporous ACs. At intermediate impregnation ratios, ACs with a wider pore size distribution (from micropores to mesopores) were obtained. Finally, high impregnation ratios yielded essentially mesoporous carbons with a large surface area and pore volume. The four best-fit three-parameter isotherms Sips, Toth, Prausnitz-Radke and Vieth-Sladek suggest that the adsorption capacity of activated carbons from orange peel for copper ions was 63 mg/g.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Orange peel; adsorption; surface area; activated carbon; Langmuir, Prausnitz-Radlke.

 


 

go to top   Environment Protection – A COMSOL Simulation of Secondary Clarifiers in the Activated Sludge Process
         by Camelia Gavrila, Ion Gruia

        Vol. 2. n. 4, pp. 503-507

 

Abstract - The purification stations for waste-waters are dynamical systems, being under important and uncontrolled variations of the debit, concentration and composition of the polluting substances. Mathematical models are essential for describing, predict, and control the results of this process. The aim of this article is to describe the modelling and simulation of activated sludge processes in the secondary clarifiers, using COMSOL Multiphysics Program. A multi-layer model of the clarification/ thickening process was presented. Based on the solid flux concept and a mass balance around each layer of a one-dimensional settler, the model is designed to predict the solids profile along settling column, including the effluent and underflow suspend solids.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Secondary clarifier, Activated sludge processes, Numerical model, COMSOL.

 


 

go to top   Reaction Kinetics and Operation in a Packed Bed Reactive Distillation Column - Condensation Reaction of 3-Bromo Benzaldehyde
         by Kiran Prajapati, Raj Arora, Jigisha Parikh

        Vol. 2. n. 4, pp. 508-512

 

Abstract - This paper presents the results of an experimental investigation on 3-Bromo benzaldehyde acetal (3-BA) liquid-phase synthesis from 3-Bromo benzaldehyde (3-BB) and mono ethylene glycol (MEG), catalyzed in acidic condition. The experiments were carried out batch wise in a glass reactor in the range of 303 -333 K in atmosphere condition. Data collected at equilibrium gave thermodynamic information and kinetic model was tested to fit the data. The obtained activation energy was 49.85 kJ/mole and 16.99 kJ/mole for forward and backward reaction respectively. A packed bed reactive distillation column has been tried to obtain 3-BA. The influence of mole ratio and different feed location has been studied.

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Keywords: Reaction Kinetics, Condensation Reaction, Reactive Distillation.

 


 

go to top   Fed-Batch Biosurfactant Production in a Bioreactor
         by Frederico A. Kronemberger, Cristiano P. Borges, Denise M. G. Freire
        Vol. 2. n. 4, pp. 513-518

 

Abstract - The biological surface active compounds, biosurfactants, are produced by some bacterial strains that degrade or transform petroleum components. These biosurfactants can be used to substitute their chemically synthesized counterparts in the remediation of oil contaminated areas due to their biodegradability advantages, production from renewable sources and functionality under extreme conditions. But the biosurfactant production is mainly studied in small scale shake flasks. In order to reduce the biosurfactant production costs, the scale-up of the process was investigated, using bioreactors. The extreme foam formation in the aerobic fermentation for the biosurfactant production was avoided using an innovative non dispersive oxygenation system. The Pseudomonas aeruginosa rhamnolipid type biosurfactant production was investigated. The experiments were carried out in a bioreactor operating in fed-batches. Concentration values up to 16.9 g/L of rhamnolipids were achieved when supplying extra nitrogen and carbon to the system. The results presented in this paper indicate that the proposed process and conduction method are viable and promising, being a very good alternative for the biosurfactant production.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Bioreactor, biosurfactant, oxygenation, Pseudomonas, rhamnolipid.

 


 

go to top   Replacing Conventional Oxygenation Systems in Bioreactors by Membrane Contactors: Modeling and Performance Investigation
         by Frederico A. Kronemberger, Denise M. G. Freire, Cristiano P. Borges

        Vol. 2. n. 4, pp. 519-528

 

Abstract - Many products obtained from microorganisms need aerobic conditions to be produced. In conventional bioreactors, the oxygen supply is accomplished by dispersive bubbling systems. But a very significant portion of the used fermentation media and the products presents an extreme foam formation during this oxygenation. This fact turns several bioprocesses very difficult to control and to reproduce and makes others completely unfeasible. Aiming at the replacement of a conventional oxygenation system by a non dispersive one, this work presents the modeling and the performance investigation of hollow fiber membrane contactors – a membrane contactor is a device that provides the mass transfer between two fluids without phase dispersion. The oxygenation in bioprocesses in normally quantified by the volumetric mass transfer coefficient (KLa), since the interfacial area is very often unknown. So, in order to achieve a specified value of this coefficient, the area of a microporous or a composite membrane contactor was determined. Besides, evaluations of the required membrane area behavior with the variation of liquid flow rate, gas pressure, porosity – for the microporous fibers – and superficial layer thickness – for the composite fibers – were carried out. For all oxygen supply requirements, the smallest area values were obtained for the higher gas pressure and liquid velocity values, due to the higher concentration gradient and smaller hydrodynamic limit layer, respectively.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Bioreactor, hollow-fiber, membrane contactor, modeling, oxygenation.

 


 

go to top   Cascaded PSA Process for the Purification of Argon Using an Oxygen Selective Zeolite X Adsorbent
         by Sunil A. Peter, Pramathesh R. Mhaskar, Arun S. Moharir, Raksh V. Jasra

        Vol. 2. n. 4, pp. 529-538

 

Abstract - The separation of argon and oxygen from their gaseous mixture by adsorption process is difficult due to the closeness of their molecular properties and adsorption behavior in porous materials. The present work deals with the conceptual design of a PSA process for the purification of an argon stream with oxygen as minor component. For the adsorbent to be used in the PSA system we studied the equilibrium adsorption isotherms of oxygen and argon up to 10 bar in strontium exchanged zeolite X (SrX) granules, which showed oxygen selectivity of 1.55 over argon at 303 K. The pure component adsorption isotherms were fitted with Langmuir adsorption isotherm model and the parameters thus obtained were validated through the simulation of dynamic adsorption of oxygen in SrX and compared with the experimental breakthrough curve of oxygen. These adsorption parameters were used for the simulation of the PSA process. Since the recovery from a single PSA system was very low, we used multiple PSA systems connected in series to increase the over all recovery of argon with purity more than 99%.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Argon purification, Pressure swing adsorption, Strontium exchanged zeolite X, Cascaded PSA system.

 


 

go to top   Energy for Sustainable Development
         by Mikhail Krasnyansky

        Vol. 2. n. 4, pp. 539-549

 

Abstract - The review provides a detailed analysis of scientific and technological aspects characterizing implementation of energy for sustainable development. This implementation includes: transition from fossil fuel to renewable energy; complete replacement of gasoline and diesel cars, trucks and buses by hybrid ones and at a later stage by electric or hydrogen cars; increase of energy efficiency for all of the exploited equipment (it is a separate huge and complex program); development and implementation of the “green” economic incentives; “green” trends for the traditional technologies. The analysis and discussion of the newest tendencies, and also conclusions and recommendations are made.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Green Energy, Energy Efficiency, Renewable Energy, Energy Savings, Sustainable Development.

 


 

go to top   Extraction and Characterization of Extracellular Polymeric Substances (EPS) from Waste Sludge of Pulp and Paper Mill
         by M. Pervaiz, M. Sain

        Vol. 2. n. 4, pp. 550-554

 

Abstract - Secondary sludge (SS) and mixed sludge (MS) from a Canadian paper mill were characterized, and investigated for extracellular polymeric substances (EPS) to explore the potential opportunity for value added utilization of waste paper sludge as wood adhesive. After basic characterization which showed the availability of significant amount of organic matter, further study of wood adhesive extenders were carried out through extraction of EPS by using 4000g centrifugation, a physical control method, and a chemical extraction technique involving formaldehyde and sodium hydroxide reagents. Gravimetric analysis showed the chemical extraction technique as being efficient method by yielding up to 5 times more EPS compared to physical control method. SS sludge, as anticipated, contained significantly high amount of EPS compared to MS. Fourier transform infrared spectrometry (FTIR) studies on extracted EPS confirmed the presence of key functional groups related to potential adhesions like protein, glucose, lignin, and carbohydrates. The polymeric nature of EPS was further diagnosed through calorimetric studies.

Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved

 

Keywords: Biomass, Secondary Sludge, Extracellular Polymeric Substances, EPS Yield, Waste Water Treatment, Wood Panel and Adhesive.

 

 


 
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