摘要:

AbstractAn account is given of the patented technique of the rotational particle separator for separating solid and liquid particles of diameter 0.1 μm and larger from gases. Attention is focused on the working principle, fluid mechanical constraints, particle design, separation performance, power consumption, dimensions, filter cleaning and costs. Furthermore, an overview is given of current developments to introduce this technique in industrial dust removal, in electricity generation and in the consumer goods market. The article concludes with a summary of the feature which distinguish this technique from existing filtering methods

ISSN:0930-7516    

DOI:10.1002/ceat.270190102

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractCross‐flow filtration is a filtration process for separation of a disperse phase from liquids. Suspension flows tangentially to a membrane and the filtrate is drawn off perpendicular to the direction of flow. Formation of a filter cake on the membrane is thus prevented, reduced, or its composition, modified. The principle of the separation is based on tow opposing effects: on the one hand, the particles are transported by the filtration flux to the membrane where they cause and increase in concentration; on the other hand, concentration differences are again reduced by the turbulence of the cross‐flow and by Brownian motion of the particles. The two mechanisms compete with each other and depend upon particle size in different ways. An energetic comparison of the two effects yields the separation law of cross‐flow filtration as a steady state solution of the Fokker‐Planck equation. The separation law has an exponential form and assigns each particle size a separation probability with which it reaches the membrane. Once on the membrane the particles may form a filter cake, flow through the pores or return to the bulk flow. If the particles remain on the membrane the ranges of layer‐free and cake‐forming filtration can be calculated from the hydro‐dynamic and geometric conditions of the cross‐flow filter. Conventional cake filtration is regarded as limiting case. In continuous cross‐flow filtration process a low separation probability through the filtration pressure on selection of the filter

ISSN:0930-7516    

DOI:10.1002/ceat.270190103

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe aim of this work is a fluid dynamics study of the structured packing Sulzer BX gauze. A new model is proposed which, on the basis of a knowledge of the dynamic component of the liquid holdup, permits calculation of the fraction of the geometric area of the packing that effectively participates in the mass transfer. Both the metal and plastic versions of the packing are studied. Experimental data are supplied on the absorption of pollutants such as HCl and SO2by aqueous solutions of NaOH in columns in cocurrent operation. The results obtained by the proposed model are in good agreement with experimental data obtained by the present authors as well as with experimental data published in the literature.

ISSN:0930-7516    

DOI:10.1002/ceat.270190104

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractExisting design codes propose different methods for the analysis for the junction region of conical and toriconical shells (limit analysis, shake down analysis, Kellog design approach, area replacement method) submitted to internal pressure load. However, now it is possible to develop generally valid an very precise guidelines based on linear and nonlinear Finite Elements‐Analyses. A clear difference is made between design with respect to fatigue strength and design according to load carrying capacity criteria. A. Major advantage of the Finite‐Elements‐Method(FEM) is the opportunity of its adaptation to given design criteria such as a strain limit or a plastification limit. It shown how design curves can be directly derived from the FE‐analysis with respect to fatigue strength (stress concentration factors) and load carrying capacity (design factors for the calculation of a required wall thickness). The materials behavior in the plastic region is considered with an without strain hardening. Large deformation effects as geometric nonlinearities can be involved in the analysis. The method can easily be applied for the analysis of other pressure vessel com

ISSN:0930-7516    

DOI:10.1002/ceat.270190105

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractWe developed the oxidation reaction of Cu(I) ion in aqueous hydrochloric solution by oxygen in a gas‐lift capillary bubble column. The method of gas‐liquid absorption with chemical reaction was used. Test data confirmed that the rate constant of the reaction is strongly affected by solution compositions, and that chloride ions induce an inhibition effect. The kinetical orders found are equal to 1 and 2 for oxygen and Cu(I) respectively. The influence of temperature on reaction rate constant showed the existence of a maximum value between 303 and 313K. The effect of gas‐liquid of gas‐liquid system on the liquid‐side mass transfer coefficientkLwas also inv

ISSN:0930-7516    

DOI:10.1002/ceat.270190106

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractA new Paradigm has been developed fro the prediction of maximum stable diameter of viscous drops in turbulent dispersions using the Voigt model. The model assumes that a drop would break if its deformation reaches unity. The prediction from the model compares quite well with the available experimental results.

ISSN:0930-7516    

DOI:10.1002/ceat.270190107

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe performance of a packed‐bed biological reactor has been analysed under sinusoidal variations of substrate concentration and temperature for zero‐order, first‐order and Michaelis‐Menten kinetics. The model equations were solved by the method of orthogonal collocation. The results show that the cyclic steady‐state conversion is not affected by cyclic variations in the feed concentration. However, cyclic temperature variations with an amplitude of 20°C significantly decrease the mean exit concentration for zero‐order and Michaelis‐Menten kinetics compared to the constant‐temperature case. The approach to cyclic steady‐state conditions is estimated to be somewhat flower for zero‐order kinetics than for the other kinetics models investigated. We conclude that temperature variations during the day or changes in the performance of upstream plant will not adversely affect the performance of a packed‐

ISSN:0930-7516    

DOI:10.1002/ceat.270190108

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThree‐Phase fluidized bed bioreactors have advantages over conventional chemical reaction systems. There is a lack of agreement over most major operational conditions, and a wide range of design variables are open to question. A large body of recent work in the field has been reviewed, with a degree of historical comparison and discussion.It has been found that aspects of fluidized bed biofilm reactors of vital importance include: choice of solid media, gas and liquid loadings, bacterial type and reactor mechanical design. A large proportion of the work in the field of three‐phase fluidization is non‐biologically specific, or not tested on a bacterially inoculated system.The majority of three‐phase fluidized bed bioreactor work is in the field of water treatment. Although this work has highlighted the potential for use of bio‐fluidized beds for this application, there are still specific problems hindering the large scale industrial acceptance of three‐phase fluidized bed

ISSN:0930-7516    

DOI:10.1002/ceat.270190109

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe scale‐up of benzoyl peroxide initiated copolymerisation of styrene and butyl methacrylate is studied here. The reaction is carried out in reactors of 3, 10 and 100 1 volume. Increasing the reactor size increase the weight average molecular weight and broadens the molecular weight distribution. Reducing the agitator diameter broadens the molecular weight distributio

ISSN:0930-7516    

DOI:10.1002/ceat.270190110

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractIn the field of fine chemicals batch process the implementation of synthesis paths results most often in the determination of the optimal operating conditions on a bench scale apparatus; successive scale‐ups are then handled in an empirical way.For multi‐phase reactions, this approach can be limited due to the coupling between the chemical kinetics and the physical kinetics of the mass transfer. This work proposes a more rational approach for the overall synthesis of Amiodarone, a widely used anti‐arrhythmic drug produced by a liquid/liquid/solid reaction. After analysing the reaction scheme and identifying the limiting steps of the process, a simplified model is proposed to describe the overall process kinetics. The latter is used to model a continuous pilot loop‐reactor packed with static

ISSN:0930-7516    

DOI:10.1002/ceat.270190111

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY