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  • Electronic Resource  (255)
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  • 1990-1994  (255)
  • 1991  (212)
  • 1990  (43)
  • Industrial Chemistry and Chemical Engineering  (255)
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  • Electronic Resource  (255)
  • Loose Leaf
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  • 1990-1994  (255)
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  • 1
    Electronic Resource
    Electronic Resource
    Drop coalescence on inclined plates in liquidsDedicated to Professor Kurt Dialer on the occasion of his 70th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 11-19 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Inclined plates are often installed as mechanical separation aids in gravity settlers for the separation of liquid-liquid systems. The authors investigated the process of coalescence of single drops on trickling films flowing off inclined plates. The method of investigation was developed by Blass and Rautenberg. It ensures that, under certain conditions, only hydrodynamic parameters influence the coalescence process to any significant extent. The coalescence time of the drops characterizes the process of coalescence. Short time between 1 and 3 seconds provide favourable conditions for coalescence whereas long times, often ten times as long or even longer are unfavourable. This contribution introduces a criterion for clear demarcation between these two ranges and also a determination of separation parameters for favourable conditions for coalescence. Furthermore, the function of the plates is described, which is determined by hydrodynamic and wetting processes. The characteristic operating regions of a plate are shown in a working diagram.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140103
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of mixing behaviour on gas-liquid mass transfer in highly viscous, stirred non-newtonian liquidsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 1-10 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: When declaring and using process engineering data such as, for exmple, mixing times or kLa values, it is assumed that these apply to the entire reactor contents. The condition of uniform mixing, necessary for this, is generally met in the regime of turbulent flow. When highly viscous and, above all, strongly non-Newtonian liquids are stirred in small reactors, there are frequently also regions of laminar flow and completely stagnant zones, which are only partially mixed or not at all. The present paper pursues the question to what extent is the gas-liquid mass transfer in stirred, highly non-Newtonian liquids influenced by the mixing behaviour of the reactor. The results show that, below certain Reynolds numbers, three relatively distinct regions exist, with different mixing intensities. Between an almost ideally mixed region in the vicinity of the stirrer and a completely stagnant and dead one, there is a zone of very slight motion. This finding demonstrates that the usual determination of integral or volume-based data in the literature is neither logical nor adequate for the case under consideration. Thus, the gas-liquid mass transfer takes place mainly in the relatively well mixed region. Therefore, use of a kLa value also requires the volume of this region to be declared. Only the knowledge of this volume enables us to correlate the kLa values in such a way that the sorption characteristics thus obtained appear suitable for scale-up. This procedure, which is illustrated by numerous examples of measured results for different stirrers, is important whenever design data for highly viscous liquids are to be worked out on the basis of laboratory measurements. Only when larger equipment is used, in which turbulent flow can be achieved, this problem does not arise because of the relatively uniform mixing of reactor contents.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140102
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of sudden pressure changes in the surrounding gas phase on flow properties of bulk solidsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 53-59 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The variation in the behaviour of bulk solids as a result of sudden pressure changes in the surrounding gas phase is of interest in the application of lock hoppers for transfer of bulk solids into pressure vessels. By using such sluice systems, problems occur due to consolidation of the pressurized bulk solids. This paper presents the results of experimental and theoretical research, which allow to describe the influence of several parameters on pressure compensation and the degree of consolidation. With reference to the forces and mechanisms responsible for consolidation, it is possible to describe the different consolidation behaviour of incompressible (limestone) and compressible (hard coal) bulk solids.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140108
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  • 4
    Electronic Resource
    Electronic Resource
    Flow characteristics of large oscillating drops in liquid-liquid systems (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 65-72 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A study was made of the flow characteristics of large oscillating drops of pure liquid-liquid systems, using a thermostatically-controlled, rising drop column, 50 mm in diameter and 1000 mm in length. Mirrors in the jacket enabled front and side views of drops to be photographed simultaneously. Single drops in the size range 5-10 mm were investigated with both mutually-saturated phases and when the solute was being transferred from the dispersed phase. The systems studied were (1) toluene and acetone (dispersed)-water (continuous), and (2) n-heptane and acetone (dispersed)-water (continuous). Acetone concentrations were varied up to 3.75 kmol/m3. The oscillations of a travelling drop were asymmetrical; therefore, the amplitude cannot be expressed accurately in terms of only two axes. The area change of the drop compared to that of a sphere of equal volume ‘ε’, was shown to represent the amplitude accurately. The periods of droplet oscillation were uniform for the mutually saturated systems of constant physical and flow properties but changed when mass transfer was taking place. The interfacial tension exerted a marked effect on the amplitude, which also depended upon the oscillation frequency. The amplitude changed with droplet size in a similar manner to the terminal velocity, i.e. it increased with increasing size until it reached a maximum, subsequently decreasing less rapidly. The drag coefficient increased with increasing rate of mass transfer from the drop. Correlation of the results and the area eccentricity ‘ε’ by dimensional analysis embracing all possible parameters and physical properties affecting drop oscillation, resulted in the correlation ε = 0.22 Sr0.42 We-0.53 M0.13 with a mean deviation of ± 14%. This will facilitate more accurate prediction of the interfacial area for mass transfer calculations, relating to equipment containing droplets in the oscillating regime.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140110
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  • 5
    Electronic Resource
    Electronic Resource
    Modelling of pressure drop in packed columns (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 89-95 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The correct choice of packing is of decisive importance for optimum process efficiency in the operation of two-phase countercurrent columns. An important criterion for this choice is the pressure drop in the gas flow. Theoretical relationships are derived for calculating the pressure drop in beds with dry and trickle packings. It has been demonstrated by comprehensive experiments that these relationships allow the pressure drop to be determined more accurately than by previous methods. The experiments were performed at the Department of Thermal Separation Processes of Bochum University on 54 different packed beds, using 24 different systems.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140203
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  • 6
    Electronic Resource
    Electronic Resource
    Calo-visco-densimeter: A multipurpose apparatusPaper presented by H. Zech at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989.Dedicated to Professor Dr.-Ing. Karl Stephan on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 109-113 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A multipurpose apparatus was designed, built and operated with the aim of a simultaneous determination of enthalpy of mixing, heat capacity, kinematic viscosity and density of liquid mixtures at 240 〈 T 〈 370 K and 1 〈 p 〈 25 bar. Its operation was monitored by a PC. Details of design and the first experimental results are presented.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140207
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  • 7
    Electronic Resource
    Electronic Resource
    An improved SRK-equation for the estimation of concentrations by inferential measurements (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 20-28 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method is proposed for solving the vapour-liquid equilibrium problem in binary distillation processes, when pressure and temperature are known. Special attention is paid to the applicability of the method for control purposes. Therefore, a comparison between measured and estimated concentrations is included for the case of propane-propylene distillation. The method is based on an improved Soave-Redlich-Kwong equation of state and is easy to implement on a process computer. It yields a close approximation of experimental vapour and liquid volumes. On applying the original SRK-equation at high pressures, an error in excess of 20% is obtained in the liquid volume which is one of the reasons why this equation cannot be used for control where high accuracy is required. In addition, the conventional mixing rule cannot reproduce the mole fractions correctly. Therefore, a new density-dependent mixing rule is put forward for modelling of experimental results.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140104
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  • 8
    Electronic Resource
    Electronic Resource
    Adsorption and desorption of halogenated hydrocarbons using activated carbon (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 59-64 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Environmental hazards caused by halogenated hydrocarbons and increasingly stringent regulations for limiting their emission require comprehensive investigations of these substances. The present work deals with the adsorption and desorption of halogenated hydrocarbons on activated carbon. The results could be useful in the utilization of landfill gases because halogenated hydrocarbons must be removed in order to avoid pollution and the loaded activated carbons have to be regenerated. Activated carbons are well suited to removal and recovery of halogenated hydrocarbons from gas flows.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140109
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  • 9
    Electronic Resource
    Electronic Resource
    Influence of intraparticle total pressure change on pore mass transportExtended version of poster presented by S. Scholl at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 213-218 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Influence of intraparticle total pressure change on pore mass transport is investigated in physical gas phase adsorption of a single component from an inert carrier medium. The Dusty Gas Model is applied to quantify pore mass transport, assuming local equilibrium between pore fluid and adsorbed phase. Calculated results for single pellet adsorption kinetics of cyclohexane on activated carbon and CO2 on molecular sieve 5 Å are compared with experimental data. It is found that the total pressure drop in the pore system may be as much as 1% of the ambient total pressure. This results in a maximum viscous flow contribution of 13% for the cases studied. Since this contribution is obtained only under conditions of low overall transport rates of the adsorbed component, the assumption of isobaric conditions within the pore system of a porous adsorbent appears justified for most cases of practical calculations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140310
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  • 10
    Electronic Resource
    Electronic Resource
    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140501
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  • 11
    Electronic Resource
    Electronic Resource
    Fluidized bed dryers: Dynamic modelling and control (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 307-310 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fluidized bed drying finds important applications in the chemical industry on account of the following advantages: (a) rapid exchange of heat and mass between drying media and particles yields the desired product quality and reduces the overall drying time and (b) easy handling of feed and product. There is much scope for improving the existing modelling techniques as applied to predicting the performance characteristics of the dryers. This should provide a sound basis for the implementation of appropriate control strategies. This report is a review of prevailing modelling, identification techniques and control strategies. Hopefully, the up to date information in this paper will be found useful for research work on fluidized bed dryIng.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140504
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  • 12
    Electronic Resource
    Electronic Resource
    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140401
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  • 13
    Electronic Resource
    Electronic Resource
    A multi-parameter model for absorption (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 379-385 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A three-parameter model for mass transfer by absorption, based on a combined effect of non-steady-state molecular and eddy diffusion through a resistance zone has been suggested, which encompasses all the existing theories on mass transfer at the gas-liquid interface. King's approach [5] to describing gas-liquid mass transfer phenomena through an eddy-diffusivity model can explain some experimental results, but does not provide a general mathematical solution of the problem. The shortcomings of the King's model are overcome in the present work and a general solution is presented. This solution confirms the experimental findings of Versteeg et al. [10] for liquid phase mass transfer. The steady-state solution of the present theory, valid for the dimensionless number α 〉 0, shows a close agreement with experimental data of Luk [22], the only source of all the information necessary for model verification.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140604
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  • 14
    Electronic Resource
    Electronic Resource
    Dynamic behaviour and simulation of a liquid-liquid extraction columnPaper presented at the “Jahrestreffen der Verfahreence-Ingenieure”, Stuttgart, October 3 to 5, 1990.Dedicated to Professor Dr.h.c. Dieter Behrens on the occasion of his 65th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 301-306 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dynamic behaviour of a stirred liquid-liquid extraction column was studied experimentally. Various input variables of the column were varied stepwise and the resulting variations in the system and output variables were measured. In addition to experimental work, a computer model was developed on the basis of the dispersion model to simulate the dynamic behaviour of the extractor. This model forms a component program of the dynamic process simulator DIVA, developed at the TU Stuttgart. The experiments showed that the hydrodynamic parameters exhibit no significant dynamic behaviour of their own. Therefore, changes occurring in these parameters closely follow variations in input and system variables. As a result, steady-state relationships for the calculation of flow parameters could be used in the simulation program. The simulator satisfactorily reproduced the experimental results for a number of disturbances. However, this was not always the case. As shown in the following, the model did not take into account the column level controller which, under certain conditions, exerts a very strong influence on the column's dynamic behaviour. As a result, larger differences occurred between experimental and simulated data. This influence on the extractor's dynamic behaviour can, however, be eliminated by a simple modification of the level controller arrangement.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140503
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  • 15
    Electronic Resource
    Electronic Resource
    Role of sparger design in mechanically agitated gas-liquid reactors. Part I: Power consumption (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 333-347 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Power consumption (Part I) and liquid phase mixing time (Part II) were measured in 0.57, 1.0 and 1.5 m i.d. vessels. A pitched blade downflow impeller (PTD) was used. Design details of the PTD impeller such as diameter (0.22T to 0.5T), blade width (0.25D to 0.4D) and blade thickness (2.8, 4.3 and 6.4 mm) were studied. The effect of sparger type and geometry on power consumption has been investigated. For this purpose, pipe, ring, conical and concentric ring sparger were employed. Design details of the ring sparger such as ring diameter, number of holes and hole size were also studied in depth. Sparger location with respect to the impeller was found to be the most important parameter and was therefore varied for nearly all the spargers studied. A correlation for the power consumption has been developed.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140507
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  • 16
    Electronic Resource
    Electronic Resource
    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140601
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  • 17
    Electronic Resource
    Electronic Resource
    Thermally safe operation of a semibatch reactor for liquid-liquid reactions-fast reactions (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 367-375 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Accumulation of the reactant supplied to a cooled semibatch reactor (SBR) will occur if the mass transfer rate across the interface is insufficient to keep pace with the supply rate. Then, due to a low starting temperature or supercooling, the reaction temperature does not rise fast enough to the desired value. This accumulation may eventually lead to a temperature runaway. We investigated the possibility of such an event for reactions of the type “chemically enhanced mass transfer” or “fast” and found that only low distribution coefficients, i.e. 10-4 or lower, can lead to accumulation. At higher distribution coefficients, the mass transfer rate across the interface of a well-mixed dispersion is generally sufficient to prevent accumulation. A thermal runaway in the fast regime exerts a moderate effect, because the effective activation energy is halved. Calculations for the “instantaneous” reaction regime, regarded as a special case of fast reactions, show that there is no runaway possible.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140602
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  • 18
    Electronic Resource
    Electronic Resource
    Role of sparger design in mechanically agitated gas-liquid reactors. Part II: Liquid phase mixing (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 386-393 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Liquid phase mixing time was measured in 0.57, 1.0 and 1.5 m i.d. mechanically agitated gas-liquid reactors. Transient conductivity technique was used for the mixing time measurement. Pitched blade downflow turbine was employed. The design details of PTD impellers such as diameter (0.22 T to 0.5 T) and blade width (0.25 D to 0.35 D) were studied. The influence of sparger types and their design on mixing time has been investigated. For this purpose, pipe, ring, conical, and concentric ring spargers were employed. The design details of the ring sparger, i.e. ring diameter, number of holes and hole size were also studied in depth. Sparger location with respect to the impeller was found to be the most important variable and, therefore, it was varied for practically all the spargers studied in this work. It was found that the liquid phase mixing time depends on the impeller design, sparger design, sparger location, impeller speed and superficial gas velocity. Correlations have been developed for the dimensionless mixing time.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140605
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  • 19
    Electronic Resource
    Electronic Resource
    A critical study of multivariable self-tuning algorithms for distillation controlIICT Communication No. 2468. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 399-405 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A control algorithm which has been acclaimed as the best algorithm for a real system may not be the best algorithm for a different real system. Therefore, various self-tuning algorithms for real distillation columns have been evaluated, in order to compare their performances. A variable forgetting factor algorithm is modified using a filter which permits the employment of one instead of two covariance matrices for distillation control. A cautious self-tuning control of SISO system is extended to MIMO system of distillation control. Multivariable self-tuning regulator, multivariable self-tuning controller and multivariable cautious self-tuning controller are implemented with modified variable forgetting factor for linear transfer function model, Waller et al. column, and rigorous non-linear model, Wood and Berry column. For distillation control, a multivariable cautious self-tuning algorithm with modified variable forgetting factor is much simpler than earlier reported algorithms. This has produced better results and demonstrated its effectiveness, even in the presence of noise when other adaptive controllers give unsatisfactory performance.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140607
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  • 20
    Electronic Resource
    Electronic Resource
    Impact of particle size dispersity on thermal conductivity of packed beds: Measurement, numerical simulation, predictionPaper presented by E. Tsotsas at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 3 to 5, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 421-427 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of particle size dispersity on thermal conductivity of packed beds without fluid flow is investigated. For this purpose, new experimental data for bi- and polydispersed packings are presented and data from the literature reviewed. All data are tabulated. The results of numerical calculations carried out for regular arrangements of spheres are also discussed. The impact of particle size dispersity on thermal conductivity is shown to be primarily due to the change in bed porosity. Thus, prediction can be carried out in the same way as for monodispersed packings if based on the actual bed porosity. A model developed by Schlünder and co-workers is revised and recommended for practical application.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140610
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  • 21
    Electronic Resource
    Electronic Resource
    Particle structure change of CaO during high temperature sulphatization (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 357-362 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of particle size (layer thickness), BET surface area and pore size distribution on the reactivity of CaO derived from limestone were studied by using a pH-stat and the BET method. Visual analysis was obtained with SEM, and X-ray diffraction was used to determine the crystalline components present. It was found that the pore size distribution, including pore volume and pore surface distribution, affected the sulphatization behaviour. The larger pores (D 〉 50 Å) with their pore volume and pore surface were to some extent responsible for both initial reactivity and ultimate capacity of CaO.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140510
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  • 22
    Electronic Resource
    Electronic Resource
    Preparation Technology for Fine Particle MeasurementDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 1-7 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Describing the disperse state is important for quality assurance, operational safety and the design and modelling of processes, especially in solids technology. Starting materials, intermediates and end products have to be characterized. Apart from representative sampling, preparation greatly influences the results of particle characterization. Very fine particles are normally agglomerated unless a highly dispersed state is stabilized by an additive. For a meaningful measurement, they must be preserved in this state or be definitely dispersed, depending on the type of problem.If the point of interest is the present disperse state with regard to the processing characteristics, e.g. for a filtration, the system should not be changed by the preparation method. If it is necessary to determine the property functions, i. e. the functional relationship between technological and physical properties, it is necessary in general to use a high dispersion energy or a long dispersing time in order to obtain the best achievable dispersion. The finer and more unstable a disperse phase is, the more the correct processing is important for the result. The problems of dispersion in gases and liquids are discussed with some examples.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080102
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    Shape Characterization of Crystals and Crystal AgglomeratesDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 48-54 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Crystals and crystal agglomerates exhibit a number of specific shape features which evolve in close relation to the conditions of growth and agglomeration. Hence the quantitative evaluation of these shape features by adequately defined shape parameters can serve to obtain a deeper insight into the mechanisms and kinetics of crystal agglomerate formation and to quantify more precisely the quality of crystallization products.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080110
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  • 24
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    Response of Single-Particle Optical Counters to Particles of irregular shapeDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 40-47 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The response of optical particle counters to nonspherical particles is analyzed theoretically and on the basis of experimental results. Theoretical approximations valid for particle diameters d ≪ λ and d ≫ λ (where λ is the wavelength of light) are used to derive some general predictions about the influence of the particle shape on light scattering. These predictions are compared with experiments on six optical particle counters using nonspherical particles. The instruments differ in the kind of illumination (laser or incandescent light), the mean scattering angle and the receiver aperture. When the particle size is smaller than the wavelength the light-scattering diameter of a nonspherical particle comes very close to its volume-equivalent diameter. For irregularly shaped particles larger than the wavelength better conditions than giving a “projected area” response cannot be achieved with an optical arrangement for single-particle detection.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080109
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  • 25
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    Characterizing the Structure of Fumed Pigments using the concepts of fractal geometryDedicated Professor Kurt Lesconski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 63-71 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many commercially important pigments such as titanium dioxide and carbonblack are produced as fumes from a combustion process. The fuming process generates open structured agglomerates conforming to a morphology predicated by physical considerations. For this reason widely different chemical pigments often manifest common physical structure. This structure can be characterized using the concepts of fractal geometry. In this communication the potential usefulness and physical significance of descriptive parameters of the agglomerate structure of fumed pigments based on the concepts of fractal geometry are explored. Similar structures present in high energy ceramic powders are discussed and the potential importance of fractal dimension parameters for the prediction of the physical behaviour of powders is outlined.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080112
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    Theoretical Prediction of Energy Consumption and Particle Size Distribution in grinding and drilling of brittle materialsDedicated to Professor Kurt Leschonski on the occasion of his 60th birthdayA shortened version of this paper was presented under the title “Fracture Physics in Comminution” at the 7th European Symposium COMMINUTION, June 12-14, 1990, in Ljubljana (Yugoslavia). (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 55-62 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Based on physical assumptions, simple equations have been derived for the probability of breakage of particles, for the dependence of fragmentation energy on particle size and for the fragment size distributions as a function of mass-specific energy. The particles were considered as spheres, and Hertz theory of the stress distribution at the contact between a sphere of brittle material and a flat surface was applied in combination with Weibull statistics of failure. The predicted dependence of the probability of breakage on particle size and mass-specific energy agrees well with experimentally obtained data for single-particle experiments, even if the particles were not spherical. The resulting fragment size distribution could be predicted by the application of fracture mechanics. The theory can also be applied to rock drilling, where the breaking material is considered as a flat surface and the drilling tool as being of spherical shape. In both comminution and drilling, the experimental results agree fairly well with the theory.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080111
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  • 27
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    High-Temperature Evaporation Rates of Solid KBr and NH4Cl aerosol particlesDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 79-85 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The evaporation rates of particles of solid KBr or NH4Cl suspended in argon were studied under high-temperature conditions behind incident shock waves. The mass-transfer process during particle evaporation was observed by two optical techniques allowing the measurement of scattered light from a particle ensemble and also from individual particles. The scattered light flux signals were interpreted on the basis of the Mie theory, resulting in values for the time-dependent particle size and for the refractive index of particle materials. The experiments were performed in the gas-phase temperature ranges TG = 1070-1300K (KBr) and 525-650K (NH4Cl). The initial size of the suspended particles ranged between 0.6 and 1.0 μm. From the measured decrease in the particle size during the mass-transfer process the evaporation coefficients of both materials were determined as a function of the gas-phase temperature. They depend on the vapour pressure and the diffusion coefficient for vapour into gas. Typical parameters (àKBr, m) describing the diffusion coefficient of KBr vapour in argon and the vapour pressure of NH4Cl could be determined.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080114
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    On the Droplet Deposition and Mist Supercooling in a turbulent channel flowDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 72-78 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A combined experimental and theoretical study of the droplet deposition and mist supercooling in a turbulent channel flow has been performed. The measurement of droplet deposition on the unheated and heated channel wall was carried out using a particle-sizing two-dimensional reference-mode laser-Doppler anemomentry technique in a 41 mm × 41 mm vertical square channel at Re = 1.0 × 104 - 6.05 × 104. The dimensionless deposition coefficient kd/uZ. H. Yang Prof. S. L. Lee Department of Mechanical Engineering, State University of New York at Stony Brook, Stony Brook, NY 11794 (USA) is analyzed theoretically based on a new unified theoretical approach for the entire transverse flow region from the turbulent core to the quasi-laminar region next to the boundary wall. The proposed analytical model shows satisfactory agreement with the results of present experimental measurement. In the mist supercooling, the heated surface is cooled by the evaporation on the outside surface of an extra thin continuous liquid film which is maintained by the continuous deposition of extremely small droplets of an optimal size determined by a selection process on the droplets transverse migration due to the dynamic interaction between the phases in a parallel turbulent mist flow. The heat transfer enhancement coefficient depends on droplet deposition rate, droplet size, concentration and the Reynolds number.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080113
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    The Work of the British Standards Institution in Particle, surface and pore size characterisationPresented at the Coulter Classics Symposium, Solihull, September 26-27, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 170-172 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: British Standards committee GME/29/4 is concerned with “Particle sizing methods other than sieving”. Its work covers not only particle size distribution analysis but also methods of estimation of surface area and pore size distribution, as well as a glossary of terms relevant to those subjects. The current British Standards in the BS 3406 series (particle size analysis) and BS 4359 series (surface area) are reviewed, and a progress report is given on the status of several new and revised Standards which are in preparation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080130
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    A Procedure for Blending and Mass Balancing fine particle size data (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 164-169 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An increased interest in the development of new techniques for fine grinding has resulted in a growing concern over the accuracy of size distributions for extremely fine particles. Since most particle size analyzers have lower detection limits, care must be taken when comparing size distributions which have not been properly mass balanced.An automated technique has been developed in which a completely mass balanced size distribution can be obtained using an Elzone 80XY particle size analyzer. A computer program is used to blend the data from successively smaller orifice tubes, and to determine the weight percent of material finer than the lower detection limit of the analyzer. This result is then used to correct the distribution for the missing fine material. Experimental results indicate that size distributions obtained using this procedure are reproducible and compare favorably with those obtained using other size analysis techniques.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080129
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    Development of an Automatic System for Measuring Particle Charge and Size distributions in a clean room (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 200-208 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An automatic measuring system was developed to perform simultaneous measurements of particle size and charge distributions in a clean room and other aerosol sources. The system consists of an electrostatic condenser (EC) and an optical particle counter (OPC), which are controlled by a personal computer (PC). The PC automatically varies the voltage on the EC and converts the corresponding OPC counts to charge distributions. The reliabilities of the data inversion method and the automatic measuring system were confirmed by theoretical and experimental examinations, respectively. In the theoretical examination, inverted charge distributions were tested and compared with various assumed input distributions. In the experiment where monodisperse aerosols neutralized by a 85Kr neutralizer were used, the measurement results agreed well with the theoretical Boltzmann charge distribution. The application of this technique is demonstrated by the measurement of charge and size distributions of aerosols in a clean room.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080137
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    Sedimentation of Nonspherical Particles (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 209-214 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The motion of real oblate particles of different cross-section can be described with sufficient accuracy by equation valid for spheroids. The proof was effected by means of velocity measurements.The application of theoretical considerations to sedimentation analysis allows it to be used to calculate apparent distributions occurring in the sedimentation of monodisperse particles of uniform shape at any orientation relative to the direction of sedimentation. The transfer to polydisperse systems involves several difficulties, which can be avoided in part by suitable approximations. In the case of a particle system with a polydisperse distribution of a main axis, but a constant particle shape, it is possible to calculate the resulting apparent distributions and their deviations from those distributions obtained when applying the volume equivalent particle diameter.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080138
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    A technique for measuring contact angles at particles (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 215-221 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The behavior of particles at the phase transition between a gas or liquid and another liquid phase may be characterized by the so-called wetting (or contact) angle. In contrast to plane surfaces, which allow such measurements to be conducted relatively easily, the determination of the wetting angle between a liquid and the surfaces of fine particles demands extensive preparative measures. The method adopted by Heertjes and Kossen [12] for example, involves compressing a tablet from the powder in question, from which the wetting angle may then be derived. The compression process naturally modifies the superficial structure of the particles, and hence their wetting characteristics. This paper describes a preparation technique with which the wetting angle between a liquid and fine particles can be derived without modifying the surface texture. This involves coating and adhering a monolayer of the powder on a carrier plate and measuring the composite wetting angle of the particles and the adhesive film. The specification of the adhesive's wetting angle and areal porosity of the carrier medium allows the wetting angle of the given powder subsequently to be evaluated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080139
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    International symposium on instabilities in multiphase flows. May 11-14th, 1992, Rouen (France) (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 243-243 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080145
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    Symposium attrition and wear in powder technology. 12-14 October 1992, Utrecht (The Netherlands) (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 243-244 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080146
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  • 36
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    Light Scattering Applied to LDA and PDA Measurements. Part 1: Theory and numerical treatments (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 245-258 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mathematical tools are provided for computation of the scattered field produced by a spherical particle moving through the region of interference of two crossing laser beams. This formulation is readily applicable to laser Doppler and phase Doppler anemometers (PDAs). In particular, the geometry of PDAs is treated in the most general terms. The cases of very large and very small particles are considered in detail. In the first part the theory underlying the computer code STREU, which was produced during the present work, is discussed and relevant mathematical formulations are presented. Also, graphical tools are provided for the convenience of the designers.In Part 2 the utility of the computer code is demonstrated with the help of examples in the area of phase Doppler anemometry. It is shown that the phase Doppler technique may be used for sizing of submicron particles in addition to large particles. Measurement of particle refractive index, in addition to the diameter, is also made possible.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080147
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    The Physically Relevant Parameter Space of the Nukiyama-Tanasawa distribution function (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 287-293 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The range of the parameters of the Nukiyama-Tanasawa distribution function was analysed, leading to the identification of the physically relevant parameter space. The analysis was also applied to the Rosin-Rammler distribution function.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080152
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    Regularized Inversion of the Laplace Transform: Accuracy of analytical and discrete inversion (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 282-286 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dynamic light scattering is a technique used for the optical determination of a colloidal particle size distribution. A simple procedure, based on a trapezoidal model for the linewidth distribution function, is given for obtaining a constrained regularized inversions of correlation data obtained in dynamic light scattering experiments, and estimating the accuracy of such inversions. Based on the eigenfunction decomposition of the Laplace integral equation, error bars, which are directly related to the accuracy of the correlation data, may be placed on both analytical and discrete inversions. By using a regularization procedure, and a nonnegativity constraint, problems with statistical noise in data may be handled effectively.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080151
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  • 39
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    Mass Calibration of the Coulter Counter Model ZM (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 294-296 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The calibration of electrical sensing zone instruments is normally achieved by using spherical particles with a certified size. An alternative and more fundamental procedure, known as mass or self-calibration, is to use particles of the material under test.This work concerns the mass calibration technique, in particular the equations used to calculate the mass calibration constant. It is demonstrated that some of the published expressions are inconsistent. An expression particularly suitable for the Coulter Counter Model ZM has been derived and validated. Some experiments were also performed using irregular particles, in order to compare both calibration methods.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080153
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    Announcement (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 323-323 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080158
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140101
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    Application of dynamic programming to high-dimensional systems described by difference equationsPaper presented by R. Luus at the Second North American/German Workshop on Chemical Engineering Mathematics and Computation, Göttingen, Germany, July 15-20, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 122-126 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The application of dynamic programming using an interative procedure, which employs domain contraction and accessible grid points for the state vector, is investigated for solving optimal control problems where the system is described by a set of difference equations. A model of a gas absorber with six state variables and two control variables is used to examine the feasibility of the proposed algorithm and to analyze the effects of the grid size and of the domain contraction factor. This algorithm yields rapid convergence to the optimum even when a relatively coarse grid with as few as 11 grid points is used.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270140210
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140301
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    Effect of some operating variables on the flotation of aluminium particles (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 118-121 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of impeller speed, air flow rate, cell concentration, agitator size and cell volume on the recovery of aluminium particles have been studied in a KHD Humboldt Wedge AG machine, using alkyl benzene sodium sulphonate paste as collector and pine oil as frother. The recovery yield increased with increasing impeller speed, air flow rate, cell concentration and cell volume, up to a certain range, whereafter it decreased. A decrease in the recovery yield was observed on increasing the agitator size. A mathematical model has been developed to correlate percentage recovery with the above variables.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270140209
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  • 45
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    Development of rate expressions for the catalytic decomposition of nitric oxide with ammonia on iron oxide (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 113-117 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The reduction of nitric oxide with ammonia on iron oxide catalysts has been studied in a continuous-flow recycle reactor using simulated flue gas in the temperature range from 573 to 673 K. NO and HN3 concentrations were varied between 0 and 1000 vpm, O2 and H2O concentrations between 0 and 9 vol.-%, the remainder being nitrogen. In the presence of oxygen, the formulated reaction rate equation describes the measured rates of the main reaction NO + 2/3 NH3 ⇄ 5/6 N2 + H2O. Its form corresponds to the Langmuir-Hinshelwood type. The rate equation well fits the data, which cover the whole industrial temperature and concentration range. In the absence of oxygen, the measured reaction rates can be best described by a power law.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140208
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  • 46
    Electronic Resource
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    Vibration induced pneumatic coveyingPaper presented at the Fourth International Conference on Pneumatic Coveying Technology, Glasgow, 26 to 28 June 1990.Dedicated to Professor Dr.-Ing. Alfons Mersmann on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 141-145 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new transport system has been developed which combines vibration of the conveying pipe with amplitudes of the order of fractions of a millimetre with rather low superficial velocities of the carrier gas. This new system was specially designed for gentle transport of fragile particulate materials.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140213
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  • 47
    Electronic Resource
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    A new process for indirect gas supply by means of perfluorinated polyethers (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 127-134 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new process has been developed for indirect gas supply for culturing shear sensitive cells by means of a perfluorinated hydrocarbon. Hostinert 216, a perfluorinated polyether, was used as oxygen and carbon dioxide carrier. Hydrodynamics and mass transfer, required for industrial implementation, were investigated in a drop column. Based on the knowledge, obtained with indirect gas supply, it has been possible to construct a waste-gas free sterile pilot plant. Correlations derived from performed measurements permit design of and scale-up to an industrial plant.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140211
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  • 48
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    An automatic laboratory reactor for homogeneous polymerization of methyl methacrylatePaper presented by U. Budde at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 134-140 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An automatic stirred tank reactor of laboratory scale has been developed for on-line measurement of conversion, viscosity, and molar mass distribution of homogeneous polymerizations. For these on-line measurements, a fraction of the reaction mixture is bypassed through a densimeter and a viscometer. Samples are taken at intervals of 15 min, diluted semi-automatically, and then injected into a high performance gel permeation chromatograph for determination of the molar mass distribution of the polymers. A microcomputer collects the measured data, calculates the monomer conversion and the output data for different control units. In this study, methyl methacrylate is polymerized batch- and semi-batchwise with ethyl acetate as solvent and in the presence of different initiators. The semi-batch polymerizations are carried out at constant reaction rate by feeding the initiator and at a given increase in viscosity by feeding the solvent.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140212
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  • 49
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    Hydrodynamics, axial mixing and mass transfer in open turbine rotating disc contactor (OTRDC) (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 167-177 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An experimental study of hydrodynamics, axial mixing and mass transfer has been carried out in a newly developed liquid-liquid extraction contactor, namely the open turbine rotating disc contactor (OTRDC). It has been established that the OTRDC can be operated with larger holdups of the dispersed phase, larger interfaces and, hence, more efficient mass transfer than the conventional RDC. In correlating axial mixing data, a combined model has been applied in which both the forward mixing due to drop size distribution and the backmixing of droplets are taken into account. The RTD curves of dispersed phase predicted by the model agree well with the experimental data. Comparison of experimental mass transfer data with those predicted by the proposed axial mixing model and the theoretical single drop model shows that they are in good agreement.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140304
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  • 50
    Electronic Resource
    Electronic Resource
    Three-component mass transfer in liquid-liquid extraction with the system glycerol-acetone-water. Part 1: The influence of vanishing diffusion coefficients in binodal states on the mechanisms of mass transferDedicated to Professor Dr.-Ing. Alfons Mersmann on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 186-191 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution deals with the consequences of the decrease in diffusion coefficients at the boundaries of miscibility in fluid systems and its effect on the mechanisms of mass transfer. The liquid-liquid (1-1) extraction involving several components is taken as an example for the discussion of this topic. A short review of Hampe's theory on transport mechanisms in the transition regions of interfaces [1] explains the intrinsic interdependence between mass and momentum transfer. Finally, a discussion of the peculiarities of resistances to mass transfer in boundary layers, based on the changes in molecular transport properties, is presented.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140306
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  • 51
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    Effect of doping with nickel and copper on catalytic behaviour of wide-pore zeolites with different pore structures (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 200-208 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The catalytic properties of wide-pore zeolites, namely Ni- and Cu-doped faujastie H-Y and H-mordenite (H-M) are compared on the example of conversion of n-hexane. After thermal pretreatment of ion-exchanged zeolites, reduction with hydrogen (PH2 ≤ 40 bar) leads to a large number of metallic clusters and crystallites as well as ionic species in the zeolites. Notwithstanding this variety, the different types of catalysts can be divided into three classes: classical bifunctional catalysts (for example NiHM, NiHY) with ion exchange degrees 〉 30%, monofunctional catalysts, such as CuHM and CuHY with high copper contents (ion exchange degree 〉 40%) and metal-doped (Ni and Cu) zeolites which, depending on the conditions of pretreatment, act as bifunctional and/or monofunctional compounds and, therefore, show very unstable reaction behaviour. In addition to the extent of reduction, the cation distribution affects the activity and deactivation behaviour and, to a lesser extent, the product selectivity. The reaction mechanism of bifunctional catalysis is similar to that observed in platinum-doped catalysts, while the mechanism of monofunctional catalysis resembles the process on undoped zeolites.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140308
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  • 52
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    Decrease of diffusion coefficients near binodal states of liquid-liquid systemsDedicated to Professor Dr.-Ing. Karl Stephan on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 219-225 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This work investigates the thermodynamically based assumption that diffusion at binodal states of unstable fluid systems vanishes. It is shown experimentally that a scaling law, which describes the fall in diffusion near critical points, may also be applied in an extended form to its abatement at the limits of solubility. These results may profoundly affect the modelling of mass transfer between phases whose bulks exhibit states of saturation.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140402
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  • 53
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    Adaptive pole removal control for a batch polymerization reactor (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 240-247 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A systematic method of controller design is introduced to determine the overall charcteristic behaviour developed on process pole removal. The time delay compensation is automatically incorporated in the proposed control law. The implemented tuning parameters in the law are confined to the range between 0 and 1 to guarantee the stability of the overall control system. Subsequently, the fixed and adaptive control strategies are implemented to simulate a batch PVC reaction system. The adaptive control scheme provides good, roubust control of this simulated reactor notwithstanding the wide range of operating conditions and non-linear dynamics of the system. However, the fixed control scheme performs well only for a noise-free system. In addition, two limiting control laws, derived from the proposed method, are also used to simulate the reactor. The results indicate that these laws are not suitable for this non-linear reaction system.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140405
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  • 54
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    Three-component mass transfer in liquid-liquid extraction with the system glycerol-acetone-water. Part 2: Calculation and experimental investigation of three-component mass transfer in a countercurrent extraction column (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 253-263 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article describes the effects which occur during three-component mass transfer in liquid-liquid extraction between saturated and undersaturated phases of the system glycerol-acetone-water. The description is based on experiments in a countercurrent spray column. The physical modelling starts with the balance equations of phase flows, taking into account the variation of concentrations and mass flow rates along the column axis as well as backmixing effects. In addition, recent findings on the mechanisms of mass transfer in saturated and undersaturated phasses, deduced from theoretical and experimental results, were used to formulate mass transfer coefficients. These are valid for the region near the interface of drops in a fluid and are inserted into the balance equations. A comparison between experiments and calculations of the observed phenomena is presented.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140407
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  • 55
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    Photosensitive materials for use in velocity profile measurements in the water phase of air-water systems and in single phase liquid systems (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 275-287 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Those chemical and photochemical characteristics of a photochromic system which are necessary for successful application to flow visualization studies in water are identified. The properties of a number of photochromic and photosensitive systems are discussed, and critically examined, with regard to these requirements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140410
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  • 56
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    Simulation of a distillation column on an IBM PC, accounting for real behaviour of electrolyte solutionsPaper presented by A. Bosen at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 3 to 5, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 295-300 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution demonstrates the possibility of using a thermodynamic description of electrolyte solutions directly for computer simulation of distillation columns. Coefficients are determined for a combination of a solvation model with a local composition equation for the activity coefficient. The use of one set of coefficients yields good results of calculation of vapour pressure, vapour phase composition and caloric data of hydrochloric acid. Solution of material and heat balance equations of distillation columns is achieved on an IBM PC with the above description. Two illustrative examples of an absorption and a rectification calculation are presented
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140502
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  • 57
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    Calculation methods for multicomponent adsorption equilibriaPaper presented by S. Scholl at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 2 to 5, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 311-324 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The knowledge of multicomponent adsorption equilibria is of great importance for the industrial design and application of adsorptive purification and separation processes. As the experimental determination of the required data is time-consuming and costly, theoretical help is desirable. This contribution presents and assesses the most common theoretical approaches to the calculation of multicomponent adsorption equilibria. The models are based on the assumption of an adsorbed solution, extension of the volume filling of micropores theory or statistical thermodynamics. These models are applied to different adsorptive/adsorbent systems with ideal and non-ideal equilibrium behaviour. It is established that, at low coverages of adsorbent surfaces, all theories provide good estimates of the adsorbed phase composition and total loading while, at high saturations, no model is completely satisfactory.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140505
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  • 58
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    Theoretical analysis of gas stripping performance of spray towers (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 347-352 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simplified model has been developed to describe ammonia stripping process in spray towers. The effect of various operating parameters including air flow rate, contact time, droplet size, liquid to gas ratios and tower height on the performance of such systems has been studied in detail. The results obtained for ammonia stripping have been compared with the limited experimental data available in literature. The predicted results agree reasonably well with the reported experimental data.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140508
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  • 59
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    A New Air Classification Principle for the Particle Size range d 〈 5 μmDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 8-11 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Requirements for processes for air classification for the particle size range d 〈 5 μm are described. A classification principle and first experimental results are presented.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080103
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  • 60
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    Influence of the Particle Size Distribution on the flow behaviour of fine powders (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 101-104 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Some results are presented of investigations on the flow behaviour of very fine α-alumina powders having different particle size distributions. Shear tests were performed in a translation shear cell. The humidity was in the range 0.3 〈 pD/pSD 〈 0.6 in order to ensure the formation of adsorbed water layers only and to exclude capillary condensation. In the region of adsorbed layer bondings, the flow behaviour of very fine powders deteriorates in comparison with regions where no adsorption layers exist. An extrapolation of the unconfined yield strength for very low consolidation stresses results in an approximately constant value for different particle size distributions. In contrast, the slope of the linear function σc = f (σ1) increases with decreasing particle size up to a certain limit. For narrow particle size distributions, there is a pronounced decrease in the bulk density with decreasing particle size. Further, the bulk density is strongly influenced by the width of the distribution.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080119
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  • 61
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    Hierarchical Properties of Particle Shape for the recognition of powdered materials (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 116-123 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Particle shape recognition procedures can be used to determine constituent materials. The problem of recognizing the association between the shape and mineralogical composition of a particle, resulting from comminution of a raw ore, is of great interest.An algorithm is presented and computational results are given for the classification of particles of iso-proportional constituents. In this way, the washability function of a set of particulate raw ores can be estimated by taking into account only the contour of the particles. This classification procedure is useful when there are difficulties in the estimation of some relevant properties such as specific gravity or magnetic susceptibility.The procedure has been successfully applied to the recognition of the mineralogical composition of particles resulting from the comminution of a chromite ore and to the classification of particles in iso-composition classes.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080122
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  • 62
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    A Re-Examination of Piper's Shape Analysis Technique (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 110-115 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An image shape analysis technique which measured the angles between adjacent vectors on the image edge was previously proposed by Piper, but the accompanying data was scant. This method is shown to have great promise when applied to several images obtained using a video camera with a computer. Better data representation is obtained using a single plot of the average measured angle at each step length versus the step length. Both scale and degree of maximum roughness are immediately evident on this plot. The measured angles may be corrected to remove image circularity effects from the angles, in which case some macroscopic shape effect is also described by the plot. Similarity with the Richardson (fractal dimension) plot is discussed.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080121
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    Announcement (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 173-174 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080132
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  • 64
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    Anomalous Diffraction Effects in the Sizing of solid particles in liquids (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 175-178 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A study has been made of anomalous diffraction effects in the sizing of solid particles in liquids using a Malvern laser diffraction sizer. The particles were N.B.S. standard reference material 1004 glass spheres. The five liquids used were chosen to give a range of refractive index (R.I.) above and below that of the glass; the ratio of solid R.I. to liquid R.I. (m) ranged from 0.92 to 1.15. Measurements were made of the change in the light energy distribution pattern as the value of | m - 1 | was in creased or reduced towards zero. At high values of | m - 1 | the measured light energy distribution pattern was predicted adequately by the Fraunhofer diffraction approximation to Mie theory and the Fraunhofer computer software could be used to derive particle size distribution from the light energy pattern. For values of | m - 1 | near to zero, the Fraunhofer approach was in error but the anomalous diffraction approximation and software proved adequate for the back-calculation of size distribution from energy pattern.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080133
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  • 65
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    Mean Particle Diameters. Part II: Standardization of nomenclature (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 237-241 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the science of particulate systems, existing nomenclature systems are not always consistent with each other. The same is true for their physical relevance. A coherent nomenclature system for denoting mean particle diameters is recommended and its physical relevance demonstrated. Comments have been made on a nomenclature for particle-size distributions to support the proposed nomenclature for mean particle diameters. This nomenclature system does not contain any ambiguities and clearly conveys the physical meanings of mean particle diameters.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080143
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  • 66
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    Design Data for Cyclones (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 301-307 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: For many years efforts have been made to describe the complex process of particle separation in cyclones, and a multitude of separation models have been set up. A comparison of such separation models fails because insufficient usable test results are available and systematic and precise investigations are missing.It is important for the design of cyclones to rate their separation properties by means of the fractional collection efficiency. On account of the known measuring problems, the data supply of reliable fractional efficiency curves of cyclones is still too small. Fractional efficiency as a function of the entrance velocity was measured with a high-speed optical measuring technique. Measurements of low dust concentrations are presented. Geometrically similar cyclones of four different sizes were investigated. The fractional efficiency curves are plotted versus dimensionless parameters and the validity of the design criteria gained in this way is shown. The influence of particle shape on the fractional efficiency curves is discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080155
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    Fluid mechanics of circulating fluidized beds (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 29-38 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A fluid mechanical model of segregated vertical gas-solids flow has been developed. Mass and force balances were set up with the aid of this model and, finally, a dimensionless state and pressure drop diagram was calculated. In this diagram, the pressure gradient caused by the solids transport is plotted in dimensionaless form versus the superficial gas velocity in the form of a particle Froude number. Parameter is the ratio of the solids volumetric flow rate at minimum fluidization to the gas volumetric flow rate. The state and pressure drop diagram is valid for a given gas-solids system, i.e. for a given Archimedes number and given minimum fluidization porosity. The fluid mechanical behaviour of different types of circulating fluidized beds can be explained with the aid of the state and pressure drop diagram for segregated vertical gas-solids flow. As an example, the operating behaviour of circulating fluidized bed with a syphon in the solids downcomer is discussed. Measurements of the circulating solids mass flow rates are compared with calculation results.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140105
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    Apparatus for steady-state kinetic measurements of the catalytic reduction of nitric oxide by ammonia on iron oxide (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 39-44 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The reduction of nitric oxide with ammonia on an unsupported iron oxide catalyst has been studied in a continuous-flow recycle reactor using simulated flue gas. The responses of the employed reactor system to step and pulse inputs of tracer indicate that the system could be regarded as a continuous stirred tank reactor (CSTR). Preliminary tests were carried out to determine the effect of temperature and particle size on the measured reaction rates. Additional experiments were performed in order to study the influence of oxygen and water concentration on these rates. A gas chromatographic system has been developed to analyze the gas components NO, N2O, NO2, NH3, H2O, O2, CO2 and N2. In addition, the concentrations of NO and NO2 were measured with a nondisperse infrared (NDUV/NDIR) analyzer.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140106
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  • 69
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    Cooling of arc furnace electrodes with heat pipesPaper presented by K.-G. Bullerschen at the meeting of the “GVC-Fachusschuß Hochtemperaturtechnik”, Köln, January 19 to 20, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 45-53 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Combination electrodes with water cooling shanks, which have been introduced to reduce graphite consumption in UHP furnaces, cause the danger of vapour explosions in case of breakIng. Heat pipes are highly efficient two phase heat conductors which could provide a safer alternative to water cooling shanks, since they contain only a small amount of liquid. The transport of energy results from evaporation of the working fluid in the heated section, convection of the vapour to the cooled section and reflux of the condensed fluid to the heated end. Large heat quantities can be transferred under nearly isothermal conditions within the tube, as long as certain limits are not exceeded. The operating temperature can be controlled by design parameters such as the thermal resistance of the cooling zone. The proper function of heat pipes for cooling arc furnace electrodes is investigated by comparing the calculated heat load with temperature dependent limits to heat transport. It is shown that copper tubes with water as the working fluid combine efficient cooling and safe performance in the low temperature range, while the cheaper steel tubes with sodium filling are suitable for high temperature operation.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140107
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  • 70
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    Coke removal from a zeolite catalyst by supercritical fluidsDedicated to Professor Karl. H. Simmrock on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 73-78 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the study of the possible coke removal from zeolite catalysts, the solubility of polyaromates in supercritical fluids (SCF) was determined, showing that it becomes drastically reduced with increasing molar mass. Experiments with supercritical ethyl benzene and benzene showed that only coke precursors can be dissolved and, therefore, complete coke removal by SCF is impossible but it has been confirmed that, under supercritical conditions, deactivation of the catalyst could be slowed down.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140111
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  • 71
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    An improved method for flow network design (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 101-104 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An improved method is presented for the design of a complex flow network system. The method employs head loss and flow rate in the iteration process for the determination of flow rates and/or pressure drop. This represents a major departure from the conventional approach which uses only the flow rate. The two-step iteration method proposed here drastically improves both the convergence rate and iteration stability. Tests on different examples have shown that, for most design applications, three iterations are sufficient to yield an accurate final solution, regardless of the initial guess.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140205
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  • 72
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    A model for the rate of catalytic oxidation of methanol in a fixed bed reactor (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 96-100 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Oxidation of methanol to formaldehyde, using a mixture of ferric and molybdenum oxides as catalyst, has been studied in a fixed bed integral reactor, 150 mm long, 25 mm o.d. and 10 mm i.d. The catalyst was prepared by reaction between aqueous solutions of ammonium heptamolybdate and ferric chloride. It has been shown that, under experimental conditions similar to those employed in industry, neither external nor internal diffusion had been effective in the process and isothermal conditions prevailed in both gas and solid phases. A two-step mechanism has been put forward for the oxidation of methanol. According to such a mechanism, methanol is first oxidized to formaldehyde, accepting an oxygen molecule from the catalyst and changing the latter into a reduced form. In the second step, the reduced catalyst is transformed into the original form on obtaining an oxygen molecule from the gas phase. Based on this scheme, a rate model has been derived and verified by experimental results.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140204
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  • 73
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    Studies of drop break-up in liquid-liquid systems in a rotating disc contactor. Part II: Effects of mass transfer and scale-up (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 178-185 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The number fraction of drops of a given size which break up at rotor level in a rotating disc contactor has been observed during mass transfer in either direction to or from solvent or aqueous drops. Critical rotor speeds for a given drop size undergoing mass transfer can be used to find an effective interfacial tension. Using this interfacial tension value, the break-up fractions are correlated within experimental uncertainties in the same manner as for no mass transfer. Drop break-up fractions depend on column size and relevant empirical correlations of the data are presented. The results may be used to estimate the effect of mass transfer on drop size distributions in an RDC.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140305
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  • 74
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    Non-steady-state catalytic decontamination of waste gases (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 209-212 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The non-steady-state behaviour of a fixed bed reactor controlled by periodical direction reversal of reactant feed, applied in catalytic oxidation of industrial waste gases, containing organic compounds and carbon monoxide, has been investigated. The effects of the type of oxidized compound, its initial feed concentration, linear gas velocity, inerts-to-catalyst ratio and inerts thermophysical characteristics on the formation of reactor concentration and temperature fields were elucidated. It was shown that autothermal reactor behaviour is guaranteed by concentrations of the oxidized component which ensure an adiabatic temperature increase in excess of 20 °C. Deviations of either flow rate or initial concentration of the oxidized compound do not disturb the operational stability.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140309
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  • 75
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    On the falling-rate period (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 234-239 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A fixed bed of glass particles, wetted with water, was dried from above. The measured moisture profiles within the sample show that its surface is not completely dry during the falling-rate period. Hence, the current view, according to which the moisture front retreats into the sample directly after reaching the critical moisture content, has to be revised. Assuming that parallel dry and wet channels form within the sample during the constant-rate period, the onset of the falling-rate period depends only on the diameter of these channels. If the moisture is distributed very finely, a large number of channels with a small diameter have to be considered. The falling-rate period for this system occurs at low moisture contents. For a coarse distribution of moisture, fewer channels with a large diameter should be assumed. Their drying rates show the beginning of the falling-rate period already at high moisture contents. A good agreement between measured and calculated drying rates could be achieved by fitting the channel diameter. Only for very low moisture contents, is the agreement poor. This is to be expected, because the measured moisture profiles show a completely dry sample surface for these moisture contents, indicating that the moisture front has already retreated into the sample.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140404
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  • 76
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    Electrochemical impedance spectroscopy of oxygen and hydrogen evolution on amorphous alloys in 1 M KOHDedicated to Professor Dr. Dr. hc. Dieter Behrens on the occasion of his 65th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 263-269 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mechanisms of oxygen and hydrogen evolution on amorphous alloys G 14 (Fe60Co20Si10B10) and G 16 (Co50Ni25Si15B10) in 1 M KOH at T = 298 K and 333 K were studied by electrochemical impedance spectroscopy (EIS). Comparative measurements were carried out on polycrystalline Pt electrodes. Impedance spectra in the frequency range 10-3 Hz ≤ f ≤ 104 Hz were analyzed to determine the kinetic behaviour of amorphous alloys by application of transfer function analysis, using non-linear fit routines. The EIS-data are interpreted in terms of consecutive reaction mechanisms for both oxygen and hydrogen evolution.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140408
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  • 77
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    Operation data of a directly fired absorption heating unit with periodically operating absorberPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 3 to 5, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 226-233 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution presents the layout, construction, and experimental investigation of operation behaviour of a directly fired absorption heating unit with periodically operating absorber. The working system is CH3OH-LiBr/LiOH. The unit is designed to generate a maximum heat load of 10 kW. The field of application is mainly in domestic heatIng. A special feature of the absorption heating unit is the provision of the major part of required process heat in the heat pump mode of operation with high efficiency. At extremely low ambient air temperatures, heat is supplied in the direct mode. A numerical simulation routine is also described. The simulation program describes both steady-state and dynamic processes in the unit. With models for each component, the performance of individual components can be studied and optimized. The results presented here consist of the first experimentally obtained efficiencies in direct heating mode, results of numerical simulation of the component generator, and a comparison of measured and predicted characteristic system temperatures.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140403
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  • 78
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    Cocurrent vacuum de-aeration of water for injection into oil reservoirs (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 248-252 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Conventional vacuum stripping to reduce the oxygen content of injection water for secondary recovery of oil is carried out in packed columns with the released gases and water flowing countercurrently; hence large column diameters (normal liquid load circa 100 m3/(m2h)) and foaming that requires the addition of defoaming agents. Measurements with cocurrent and countercurrent flow at the same flow rate produced practically identical mass transfer coefficients. With flooding excluded in cocurrent flow, columns can be operated with higher liquid loads than in countercurrent flow. In addition, nitrogen released in the top part of the packing is better utilized as stripping gas, and foam is withdrawn as soon as it increases the pressure drop.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140406
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  • 79
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    Method of multiobjective optimization for imprecise objectives (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 363-366 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method of multiobjective optimization for imprecise objectives is presented. The problem consisted in a minimization of the distance between the set of admissible solutions and an ideal point. Applicability of the method is illustrated by the choice of best impeller from a group of seven different types tested. The optimum process conditions were selected, taking as optimization objective the maximization of kLa and minimization of PG.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140511
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  • 80
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991) 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080101
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  • 81
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    A Study of Particle Factors Affecting Dust ExplosionsDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 90-94 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Some parameters which affect the explosibility of dusts have been investigated. Important parameters are particle size, dust concentration, pore size and chemical composition. The dust explosion index measurements illustrate the importance of pore size and particle size. The reaction mechanism occurring is also important. Particles which burn at the solid surface and form gaseous products tend to react completely whereas other materials show a limited transport of the reactants.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080116
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  • 82
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    Particle Growth by Coalescence and AgglomerationDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 86-89 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A dispersed system is considered which will form its condensed phase at high temperatures and is characterized by a high density of very small supercritical nuclei. It is assumed that particle growth is determined by coagulation and (viscous flow) coalescence. The morphology of the final particles depends on the temperature history of the formation process. Compact spherical particles and agglomerates may be formed. Agglomerates result when the process temperature decreases to an extent that coalescence is quenched in the course of the growth process. The average size of the primary particles in the agglomerates is calculated by using the analysis and the approximations described in a previous paper. The growth kinetics of the primary particles are presented in a dimensionless form. The results show that the dimensionless size of the primary particles depends only on the ratio of two characteristic lengths of the system. For small values of this ratio, the size of the primary particles composing the agglomerates, although much greater than the initially formed nuclei, is independent of the volume fraction of the condensed aerosol. For large values of this parameter, the theory merges into the classical theory of perfectly coalescing spheres.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080115
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    Announcement (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 100-100 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080118
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  • 84
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    Using Sierpinski Fractals to Characterize Changes in the Cytomorphology of hepatopancreatic b-cells of porcellio scaber latreille (fam: Porcellionidae, crustacea) reared on different diets (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 124-127 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sierpinski fractal dimension analysis is used to describe the cytomorphology of hepatopancreatic large B-cell of a terrestrial isopod, Porcellio scaber Latreille (Fam.: Porcellionidae, Crustacea). Isopods were starved for six weeks, and then re-fed for two days on diets containing glucose and butter. The cytomorphological changes undergone by hepatopancreatic B-cells after starvation and re-feeding periods are characterized by their fractal dimensions. The significance of these findings is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080123
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  • 85
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    Particle Size Distribution of Inorganic Colloidal Dispersions: A comparison of different techniques (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 128-135 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The particle size distributions of a latex and of four different inorganic colloidal systems, consisting of spherical particles suspended in aqueous solutions, have been evaluated by three techniques: electron microscopy (EM, scanning and/or transmission), classical light scattering (CLS, polarization ratio method), and photon correlation spectroscopy (PCS, commercial instrument). Both light scattering techniques appear to be exceedingly sensitive to even a relatively small level of aggregation. Thus, the effect of treating the dispersions by ultrasonic energy was tested in order to establish the best experimental conditions. While a shorter sonication results in a minimum or constant value for the average particle diameter (or the polydispersity of the suspension), longer times may promote reaggregation of particles. Good correlation of the results by different light scattering techniques was found as long as the conversion to number averages of the PCS data involved the proper corrections for polydispersity. The agreement with the EM depended on the chemical nature of the dispersed particles; i.e., drying and exposure to the electron beam greatly affected the histograms in some cases.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080124
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  • 86
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    Simultaneous In Situ Measurements of Size and Velocity of burning droplets (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 136-141 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An optical instrument for simultaneous on-line measurements of the droplet size and droplet velocity of periodically generated droplets is described. This instrument is suitable for studying basic phenomena such as the evaporation or combustion of small droplets and the mutual interaction of neighbouring droplets. For the study of evaporation and combustion rates it is important to have precisely defined initial and boundary conditions. A vibrating-orifice generator is used to produce monodisperse droplet streams which are characterized by their highly coherent structure. The droplets all have the same size, the same spacing and the same initial velocity. These characteristic parameters of the droplet stream can be adjusted over a wide range as required for the specific experiment. The droplet size is measured with a sizing method of very high accuracy, which evaluates the intensity distribution of the light scattered by the droplets. The droplet diameter ranges from 10 to 150 μm. The droplet velocity is measured by a particle image displacement velocimeter and is compared with conventional LDV measurements. The results of the two methods agree very well. Typical droplet velocities lie in the range from 10 to 20 m/s. Some exemplary experimental results are presented for burning droplet streams, which show the influence of a finite spacing between the droplets on the burning rate.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080125
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  • 87
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    Particle Turbulent Dispersion in 3D Magnetic Fields by using a Lagrangian approach (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 151-158 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A Lagrangian approach is presented for the prediction of 3D dispersion in turbulent flows. A brief description of the main characteristics of the code PALAS (Particle Lagrangian Simulation) is given and the different methods for the simulation of either a fluid particle trajectory or a discrete particle trajectory are outlined. Comparisons with experimental results for particle 3D dispersion in grid turbulence with a nonhomogeneous force field are presented and proved to be very satisfactory in most instances.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080127
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  • 88
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    Monitoring the Coating of Powder Particles by the measurement of the low frequency impedance of the powders (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 159-163 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experiments with a purpose built cylindrical capacitor are used to determine the sensitivity of low frequency impedance measurements to changes in the coatings of four different industrial powders. It is demonstrated that the technique should be suitable for off-line quality control.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080128
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  • 89
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    Sieving Capture of Liquidborne Particles by microporous membrane filtration media (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 142-150 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Test methodology has been developed to measure the particle removal efficiency of microporous membrane filtration media under conditions in which sieving is the dominant particle capture mechanism. The methodology was used to determine the particle capture efficiency of a 0.45 μm membrane filter for removal of submicrometer sized particles from DI water. Particle capture was found to be a strong function of particle diameter, filter media thickness, and filter loading. Particle removal efficiency increased with increasing particle diameter and media thickness. It decreased with increased filter loading when the filters were challenged with the smaller particles used in this study. Removal efficiency initially decreased then subsequently increased during loading with larger particles. Capture was independent of filtration velocity and particle concentration. A sieving model was developed to predict particle capture by the filter media as a function of particle diameter, filter thickness and filter loading. The model was found to accurately predict breakthrough of monodisperse particle suspensions through the media. Particle breakthrough occurred more slowly than predicted when the filters were challenged with a polydisperse particle suspension.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080126
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  • 90
    Electronic Resource
    Electronic Resource
    Announcement (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 173-173 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080131
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  • 91
    Electronic Resource
    Electronic Resource
    Characterization of BCG Vaccine by coulter counter and scanning electron microscopic techniques (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 194-199 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: BCG vaccine, an important immune stimulant used in cancer therapy, consists of a suspension of living and dead cells, cellular fragments and aggregated cells. For this reason, nephelometric methods are unable to determine the total numbers of cells in a vaccine system. Scanning electron microscopy has enabled average cell dimensions to be obtained of length 2.36 μm, width 0.47 μm (n = 1,227), equivalent to a spherical particle of volume 0.3887 μm3 and diameter 0.9055 μm. Measurement of the particle size of a diluted vaccine with a Coulter Multisizer, fitted with a 50 μm diameter orifice, enabled the total number and average size of aggregated cells to be determined. Multiplying the total number by the number of cells in an average aggregate (obtained by dividing the volume of the average aggregate by the average cellular volume) provided a direct estimate of the total number of cells in the system. The total wet weight of cells present in a vaccine ampoule can be estimated by measuring the methylated esters of palmitic acid (PAME) in the system using gas chromatography. This weight, divided by the weight of an average cell, provided an independent confirmation of the total number of organisms present. In order to obtain the cellular density a Percoll gradient sedimentation was carried out. Surprisingly the organisms separated into two fractions of closely similar density, an average value of 1.070 g/mL being obtained. The two fractions had different average sizes with different distribution functions.When data for a number of lots of TiceTM substrain prepared over a twenty-two year period were compared, the correlation between the Coulter and PAME methods was seen to be relatively good, bearing in mind the intrinsic variability of biological systems. Comparison with viability (colony-forming unit) measurements demonstrated a loss in viability with time after preparation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080136
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  • 92
    Electronic Resource
    Electronic Resource
    Top-Hat Beam Technique: Improvements and application to bubble measurements (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 222-228 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new-generation velocimeter/sizemeter is described. Size measurement is based on the top-hat beam technique. Velocity measurement is carried out by using laser Doppler velocimetry. Advantages and limitations of the top-hat beam technique are discussed and compared with other techniques (pedestal, visibility, phase Doppler). Bubble diagnosis in a turbulent pipe flow is reported.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080140
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  • 93
    Electronic Resource
    Electronic Resource
    Asbestos Fiber Concentrations Resulting from the Installation, maintenance and removal of vinyl-asbestos floor tile (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 233-236 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents the results of a systematic study to measure the exposure to asbestos fiber concentrations associated with occupational use of asbestos-containing floor tile. Specifically, air measurements were made during floor tile installation, maintenance and removal. The procedures for these tests are outlined and the results of the air sampling and analysis are discussed.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080142
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  • 94
    Electronic Resource
    Electronic Resource
    Measurement of Asbestos Fiber Concentration above Floor Tile (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 229-232 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents the results of experimental tests designed to determine the amount of airborne asbestos, if any, released from vinyl-asbestos floor tile due to pedestrian trafficking. These tests involved the use of several human subjects to continuously walk on vinyl-asbestos floor tile in a controlled environment for an extended period of time. Similar trafficking tests were conducted on a non-asbestos, all-vinyl floor covering for comparison purposes. During the trafficking tests, continuous air sampling was performed through high efficiency filters for later analysis. The collected samples were then subjected to extensive analysis to characterize the collected particulate matter. Use of the optical microscope, scanning electron microscope (SEM) and transmission electron microscopy (TEM) allowed a detailed description of the collected material to be made.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080141
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  • 95
    Electronic Resource
    Electronic Resource
    Sixth workshop on two-phase flow predictions. March 30-April 2, 1992, Erlangen (Federal Republic of Germany) (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 242-242 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080144
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  • 96
    Electronic Resource
    Electronic Resource
    Control and Use of a Miniaturized Droplet Generator (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 297-300 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A miniaturized droplet generator with some new features, working on the principle of laminar liquid jet instability and break-up was designed. The instrument has been used to study the dispersion of monosized droplets in a turbulent swirling flow, exhibiting the main features of combustion chamber flows of modern gas turbines.The operating range of the generator was evaluated by phase-Dopper anemometry (PDA). It was demonstrated that the device also works in some metastable operating modes, producing coherent droplet streams with very small standard deviations for drop size and drop velocity. Special attention was directed to the reliability of the device and to the control of drop size. The PDA measurements showed that, in contrast to the evaluated optimum excitation frequency, the drop size cannot be determined from the orifice diameter.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080154
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  • 97
    Electronic Resource
    Electronic Resource
    An Algorithm for Determination of the Size-Dependent breakage frequency of droplets, flocs and aggregates (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 315-322 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method, based on the use of discrete size classes, is developed to extract size dependent breakage frequencies from sequential measurements of the size distribution. In order to obtain good resolution and allow for several breakage modes, interlaced Fibonacci series are used to define the size classes. Both binary and ternary breakage are considered. An approach based on Kernel Discriminant Analysis is used to focus the breakage at the discrete size classes. The algorithm is tested using simulated distribution data. The sensitivity of the retrieved breakage frequencies to the assumed progeny distribution and to the number of breakage events between samples is considered. The numerical experiments show that the method is effective even when the breakage mechanism is not well understood.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080157
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  • 98
    Electronic Resource
    Electronic Resource
    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140201
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  • 99
    Electronic Resource
    Electronic Resource
    Studies of drop break-up in liquid-liquid systems in a rotating disc contactor. Part I: Conditions of no mass transfer (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 79-89 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Observations on the break-up of single drops in a rotating disc contactor show that there is a critical rotor speed below which drops of a given size do not break. Weber and Reynolds numbers are required to correlate the data and not simply a Weber number as for turbine agitated systems. The probability of break-up of a drop at the rotor edge is expressed in terms of a Weber number with a lower limit for critical conditions. The mean number of daughter drops produced on break-up is correlated as a simple function of drop diameter based on the critical diameter and agreement is found with data from other types of agitated equipment.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140202
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  • 100
    Electronic Resource
    Electronic Resource
    A new pneumatic bearing dynamometer for power input measurement in stirred tanks (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 105-108 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A turntable dynamometer has been constructed for the accurate measurement of power input and mixing applications in bench stirred tank reactors. The main feature of this device is a pneumatic bearing with complementary conical parts. The conical pneumatic bearing permitted to apply eccentric loads without affecting its stability. The static friction torque in the pneumatic bearing was very small, 4 × 10-4 Nm, and can be neglected in the experimental ranges of measured torques, i.e. from 5 × 10-3 to 2.21 Nm. In accordance with the instrumentation used, the deviations obtained with the apparatus are less than 10% at low torque readings. At moderate torques, deviations lower than 1% are routinely obtained. Several power input measurements show that the obtained data scatter is lower than 2.5%. The power input response in the turbulent regime is in agreement with dimensional analysis: the power input depends on the cube of the impeller speed. In addition, data obtained with a turbine impeller under ungassed conditions agree with the predictions of a published correlation, which takes into account several geometrical parameters.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140206
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