bluuebunny/crossref_metadata_2025 huggingface dataset:
Zur Endlagerung radioaktiver Abfälle
Authors: Proske R.
Published: December 2004

Disposal of Radioactive Wastes. In this paper the problems and the status of the disposal of radioactive wastes in geologic formations are discussed, particular attention being paid to the suitability of salt formations. Furthermore, experiments on the disposal of radioactive wastes carried out in the former salt mine Asse are also described. After considering the concept of the future repository in the Waste Management Center the safety of such geological and mining disposal systems is examined and alternatives are discussed.
Meßmethoden konvektiver Stoffübertragung
Authors: Kottke Volker , Blenke Heinz
Published: December 2004

Methods of measuring convective mass transfer. The principal methods of measuring convective transfer of momentum, heat, and mass are surveyed on the basis of the three‐fold analogy existing between the transfer of momentum, heat, and mass. The most simple and most sensitive method is the mass transfer technique based on the principle of absorption with chemical reaction and coupled colour reaction. It is shown by selected examples that this measuring technique is already developed to the point where it serves adequately for the solution of most complex problems met with in practice. It is distinguished by its high accuracy of measurement, simple application, high local resolution, and its utilizability both for developable as well as for undevelopable surfaces. By way of the local mass transfer observable as colour‐intensity distribution it also affords a simple and illustrative means of making flow processes on solid surfaces visible. The quantitative evaluation is accomplished by reflectance photometry; quantitative image processing methods are available for complex distributions. In addition, it is shown that the mass transfer technique is also suitable for practical utilization as a method for measuring turbulence. The measuring principle is based on the extremely high dependence of the length of transitional separation bubbles in the nose section of flat plates of finite thickness in longitudinal flow on the turbulence intensity.
Vermischungseffekte in Flüssig/Flüssig‐Extraktionskolonnen
Authors: Marr Rolf , Moser Franz
Published: December 2004

Axial mixing in liquid/liquid countercurrent extractors. Methods are considered for the determination of longitudinal mixing in many countercurrent extractors. It is found that only the single phase mixing of the continuous phase can be accurately determined; with certain reservations this also applies to the disperse phase. In the case of RDC and ARD in particular, correlations are available which permit calculation of Bodenstein numbers for both phases. Such scale‐up calculations are not recommended for many extractors. It is very important to establish adequate correlations for calculation of mixing of the disperse phase in order to obtain exact dispersion heights in connection with those of the continuous phase.
Beschreibung der Bewegungsvorgänge diskret‐disperser Systeme durch das Diffusionsmodell
Authors: Ebert Fritz
Published: December 2004

Description of the motion of collectives of particles by the diffusion model. The paper deals with the problems involved in the use of the diffusion model, initially established for molecular systems, to the motion of collectives of particles. Under the following conditions the diffusion model provides a reasonable description of the motion of particles suspended in turbulent flow: The collective of particles enclosed in a volume small compared with the characteristic length of the flow configuration must be sufficiently large for interpretation of the particle concentration and the transport coefficients as field variables. The time for a statistically mean step of the particle motion, given by the Lagrange integral scale, must be very small compared with the mean residence time in the flow configuration. Aerosol deposition and air classification of finely dispersed solid particles are treated as practical examples.
Feste Ionenleiter, Grundlagen und Übersicht
Authors: Rickert Hans
Published: December 2004

Solid ionic conductors – a review. The conductivity of solid electrolytes, like that of liquid electrolytes, is determined by the concentration and mobility of the mobile ions. There are solid electrolytes in which all particles of one particular type are mobile and the mobility of these ions is as great as that in molten salts or liquid electrolyte solutions. A partial lattice of the otherwise solid crystal is then in a quasimolten state. The conductivity itself now has values as in salt melts or concentrated liquid electrolyte solutions. The solid electrolyte has then reached the maximum value for the ionic partial conductivity. Important solid electrolytes with high ionic conductivities are discussed.
Einführung in die Transportvorgänge in konzentrierten wäßrigen Elektrolytlösungen und Salzschmelzen
Authors: Richter Joachim
Published: December 2004

Introduction to transport phenomena in concentrated aqueous electrolyte solutions and molten salt mixtures. Up to this day there is no general theory of liquids. Since water‐free molten salt mixtures are simpler in their structure than concentrated aqueous electrolyte solutions, it would be reasonable first to develop a theory for molten salts and then to apply this to aqueous electrolyte solutions by approximation. Such a theory does not yet exist. In this paper the system water + salt is therefore considered in the concentration range between pure water and pure salt in the liquid state. The phenomenological coefficients and friction coefficients of the different species of the system calculated from transport data are characteristic parameters for the entire concentration range which will probably offer possibilities for the analysis of transport phenomena, in close relation with the structure of the water + salt mixture. Common and essentially different properties, such as reference system and condition of electric neutrality, are discussed for concentrated aqueous electrolyte solutions and molten salt mixtures. The investigation of transport numbers from concentration cells with transference and the determination of the interdiffusion coefficients are illustrated for the system H2O + CaCl2 (highly concentrated electrolyte solution) and LiNO3 + AgNO3 (molten salt mixture). The phenomenological coefficients and the friction coefficients are calculated from the measured transport data.
Zukunftssichere und umweltneutrale Beseitigung von Industrieabfällen
Authors: Heitmann Aloys
Published: December 2004

Low environmental‐impact disposal of solid, liquid and semisolid industrial residues. In many production plants, waste residues are formed which must be treated before their disposal so as to safeguard against environmental pollution. Industrial methods for the treatment and disposal of residues are so multifarious that each disposal problem requires careful consideration so as to ensure selection of the most suitable method, both from the ecological and economical point of view. Dumping grounds cannot accommodate all waste materials without endangering or disturbing the environment. For incineration, proven methods are available which can be modified to suit the particular waste problem at hand. After a suitable pretreatment every effort must be made to achieve a waste free from organic materials, an optimum utilization of heat and a flue gas purification without inadmissible loading of waste gases and waters. In recent years there has been a considerable increase in research and development activities in the area of thermal treatment of solid, liquid and semi‐solid wastes. Worth mentioning are the high‐temperature methods giving favourable emission values and methods for degasification and gasification directed at the recovery of important raw materials. Plants based on these principles are currently being operated on the pilot scale.
Tendenzen beim Bau von Anlagen für die Düngemittelindustrie
Authors: Wagener Dietrich , Laue Karl Heinrich
Published: December 2004

Trends in the construction of plant for the fertilizer industry. As shown by the example of an ammonium nitrate plant, savings in plant operation can be achieved and environmental pollution decreased by process modification. If the neutralizing reactor is operated at elevated pressure the steam evolved can be utilized as process steam. On neutralization at normal pressure, polluted steam escapes to the atmosphere and is wasted.
Exergetische Bewertung des Einsatzes von Wärmepumpen (Brüdenverdichtern) in Anlagen der Chemischen Industrie
Authors: Stockburger Dieter , Bartmann Lutz
Published: December 2004

Energy evaluation of incorporating heat pumps (vapour compressors) in chemical plant. Both the prevailing tendency of steeper price‐hikes for fuel than for equipment and the imminent shortage of conventional fuels are stipulating measures aimed at decreasing energy consumption. The energy requirements of different variants of a particular process can be compared by using an efficiency based on availability, if the lowest process temperature is used instead of the commonly applied ambient temperature. The method is explained with reference to two examples.
Einfluß thermodynamischer und fluiddynamischer Vorgänge auf die Notentspannung chemischer Reaktoren
Authors: Gärtner Dieter , Giesbrecht Hartmut , Leuckel Wolfgang
Published: December 2004

Influence of thermodynamic and fluid dynamic mechanisms upon the emergency pressure relief of chemical reactors. The cross‐sectional areas of pressure relief devices for storage tanks and reactor vessels containing liquids under vapour pressure, which might undergo dangerous heating up, have so far been estimated on the basis of physically questionable procedures. This report analyses the pressure relief process using several extreme assumptions with regard to momentum and heat transfer in two phase flow. A conservative method of estimation is found under the assumptions of homogeneous flow and vapour‐liquid equilibrium. Using this procedure, a parametric study of the pressure relief process for a runaway polymerisation reaction has been carried out. Finally, recommendations are given concerning design of the vent line and control of the atmospheric dispersion of the relief stream via the jet exit momentum.
Gewässerschutz in der BASF AG, Ludwigshafen
Authors: Engelhardt Hubert , Haltrich Walter G.
Published: December 2004

Waste water purification at BASF, Ludwigshafen/Rh. The manifold problems encountered in the field of waste water treatment in the chemical industry are considered, together with the tasks involved, possible solutions, and costs incurred, for the example of BASF AG in Ludwigshafen. This example is particularly interesting because it shows how the waste water problems of a chemical factory that has been in existence for over a centurvey could be solved in the course of a ten‐year plan. Twenty years after the inception of this plan, costs and success can now be quantified.
Auslegung von Granulierteller und Granuliertrommel
Authors: Sommer Karl , Herrmann Walter
Published: December 2004

Disign of granulating plates and granulating drums. Equations relating mechanical and geometrical parameters have been derived for use in calculating the power requirements of granulating plates and granulating drums. An attempt is made to maintain the same product properties, especially the porosity and size of the agglomerates, on scale‐up of the granulating equipment. This condition considerably limits the possible operational parameters. In order to define the operating conditions on scaling‐up from model experiments, their influences are described in terms of theoretical models and empirical results. The utility of the expressions derived is illustrated using the design of a granulation plate as example.
Großtechnische Herstellung von Reinstsilicium
Authors: Silbernagel Heinz
Published: December 2004

Large scale production of hyperpure silicon. Silicon still remains one of the most important elements in use in semiconductor technology. Worldwide production of silicon amounts to more than 1000 t/year. Its use in semiconductor components calls for special requirements, such as extreme purity in the ppb‐range, absolutely perfect crystals, and narrow dimensional tolerances and special surface properties of fabricated silicon slices. Reaction of 95% pure metallurgical grade silicon and hydrochloric acid results in trichlorosilane, which is then purified by distillation. This is subsequently subjected to a reductive cracking process in order to produce hyperpure polycrystalline silicon. Monocrystalline silicon rods are then manufactured by one of two crystal growing methods, either by crucible pulling (Czochralski) or by float zoning. The single crystals thus obtained are then sliced by diamond cutting machines. Depending on their final use the slices are then processed by lapping, polishing, epitaxy, etc.
Über die Herstellung von Cellulasen und die enzymatische Spaltung von Cellulose
Authors: Linko Pekka
Published: December 2004

Production of cellulases and enzymatic cleavage of cellulose. Recent work on production of cellulolytic enzymes and on enzymatic degradation of cellulose is described. For optimum enzyme production by Trichoderma reesei under carefully balanced growth conditions, cellulose levels as high as 2% may be employed. Nitrogen deficit may be economically avoided by adding organic nitrogen in the form of distiller's spent grain and dried ground T. reesei cell mass. Semicontinuous production has been shown to offer further special advantages. Cellulase activity may be directly monitored automatically in a computer‐controlled pilot fermentation system. Xylitol and furfural process wastes have been shown to be suitable substrates for cellulase, requiring little or no costly pretreatment. The rate of cellulose hydrolysis is considerably increased by combined use of T. reesei and cellobiase active microorganisms such as Aspergillus phoenicia.
Methodisches Konstruieren einer Anlage zur Herstellung von Atemkalk
Authors: Rodenacker Wolf G. , Schäfer Jürgen
Published: December 2004

Methodical design of a plant for the production of CaO for use in breathing equipment. The methodology of design nowadays taught at all technical universities can also be profitably applied to chemical engineering. Methodical examination of the production process for CaO used as CO2 absorber in respiratory equipment leads to a considerable improvement in product quality and to more economical production.
Hydrodynamisches Verhalten und Stoffübergang an Siebböden im Sprudel‐ und Sprühbereich
Authors: Sawistowski Henry
Published: December 2004

Hydrodynamic and mass transfer behaviour of sieve plates in the spray and bubble regimes. An attempt is made to set up idealized hydrodynamic models for the bubble and spray regimes on sieve plates and thus to provide a basis for calculation of mass transfer and concentration ratio. Comparison of the dependence of plate efficiency in the two regimes on various parameters indicates the importance of being able to determine a practical phase transition point. This was defined on the basis of the contribution of the bubbles and droplets to the overall interfacial area and compared with the transition points of other authors. The operation of columns in the spray regime, formerly regarded as undesirable, now possesses considerable industrial significance. This was mentioned by Zuiderweg [29] in his Underwood lecture of 1973. Since that time larger perforations and higher gas velocities have been employed. There has consequently been a significant shift of sieve plate behaviour from the bubble to the spray regime. It is estimated that almost 80% of all industrial sieve plate columns now operate in the spray regime and should be specifically designed for such operation.
Meteorologische Probleme bei der Bestimmung von Schornstein‐Mindesthöhen
Authors: Manier Gerhard
Published: December 2004

Meteorological problems in determining minimum stack height. In the Federal Republic of Germany the minimum stack height must be determined with the aid of the “TA Luft” code. The method of determination has been developed with a number of simplifications concerning constancy and homogeneity of emission data, meteorological parameters, and topographical structure. The influences of these simplifications are discussed, and improved methods of determining necessary stack heights are described.
Pyrolytische Rohstoff‐Rückgewinnung aus Sonderabfällen
Authors: Collin Gerd , Grigoleit Georg , Bracker Gerd‐Peter
Published: December 2004

Pyrolytic recovery of raw materials from special wastes. The pyrolytic techniques developed especially for producing smelting coke from coal and in petroleum refining can be applied to the thermal decomposition of waste materials having a high organic content. Fluidized bed reactors and rotary kilns are particularly suitable as universally applicable pyrolysis units for continuous operation. Highly aromatic pyrolysis oils for use as chemical raw material, heating gases for the autothermic operation of the pyrolysis unit, and carbon and solids containing nonferrous metals are obtained from plastics waste, used tires, old cable, shredder wastes, and acid resins at reactor temperatures of about 700°C. Largescale applicability and economics of the process have yet to be proved.
Eignung von kontinuierlich durchströmten Mischern zum Homogenisieren
Authors: Henzler H. J.
Published: December 2004

Suitability of continuous flow mixers for homogenization. The homogenizing characteristics, calculation of power consumption, and the scope of continuous flow mixers are reported. An attempt is made to summarize the present state of knowledge in this area. Some experimental results are presented which have been obtained in the homogenization of gases or liquids in pipes and containers in which mixing was achieved by jets, built in flow‐directing fittings, stirrers or a combination of these. The investigations extend from the laminar to the turbulent range of flow. A comparison of energy requirements for the various apparatus affords important data for the choice and design of continuous flow mixers.
Fortschritte bei der Modellierung von Festbettreaktoren
Authors: Hofmann Hanns
Published: December 2004

Progress in the modeling of fixed bed reactors. Recent work on the modeling of catalytic fixed bed reactors have led to more realistic mathematical models and to a better understanding of problems connected with modeling. Nowadays standard routine computer programs are available for use in the design (and analysis) of catalytic fixed bed reactors for very complex reaction systems. The influence of bed structure on transport parameters was illustrated by experimental determination of axial and radial concentration and temperature distribution. Moreover the problem of multicomponent diffusion coupled with complex reactions in porous catalysts has been solved and can be included in the reactor model. However, the practical application of possible reactor models is limited by the availability of transport parameters for fixed beds.
Blasensäulen‐Reaktoren mit suspendiertem Feststoff: Grundlagen — Auslegung — Anwendungen
Authors: Hammer Hans
Published: December 2004

Bubble column reactors with suspended solids – fundamentals, design, and uses. The article describes the determination of hydrodynamic functions such as bubble size frequency distributions, relative gas contents, Sauter diameters, and specific interfacial areas in various liquids and in binary and ternary mixtures of organic liquids. The article also covers the local variation of these quantities as a result of coalescence, and axial and radial mixing coefficients. Formal Reynolds' analogies could be set up for heat and mass transfer – both across the gas/liquid interface and at the solid wall/bubble column interface without or with suspended solids. A brief survey of industrial processes in three‐phase reactors, especially in petrochemistry and biotechnology, closes with an indication of the expected growth in importance of such reactors as a consequence of the present trend towards heterogenization in homogeneous catalysis.
Meßtechniken zur Bestimmung der Eigenschaften von Blasen in Blasensäulen
Authors: Buchholz Rainer , Zakrzewski Wolfgang , Schügerl Karl
Published: December 2004

Techniques for determining the properties of bubbles in bubble columns. Three different methods for the determination of bubble size parameters namely (i) flash‐photography followed by image analysis, (ii) use of a conductivity probe with two electrodes and electronic processing of the signals, and (iii) the electro‐optical probe with the same signal processing as the conductivity probe are compared and contrasted from the viewpoint of their optimal use, their accuracy, and their scope of application.
Elektrische Energie und Umwelt
Authors: Krieb Karl Heinz , Dorstewitz Ulrich
Published: December 2004

Electrical energy and environmental protection. Power plant affect their environments by emitting noise, heat, and air pollutants, but can be operated, according to the present state of the art, in such a way as to lessen these effects. The noise levels will then be below those of a quiet restaurant; the heat emission above the cooling tower will influence neither climate nor the volume of rainfall, and will influence the amount of incident solar radiation to only a minor degree; the dust emission in g/k Wh has decreased by 97% during the last 30 years; the SO2 emission will have decreased by 80% by 1980; the dilution of the SO2 emission through use of high stacks will lead to maximum SO2 levels of 2 μg/m3 in case of modern power plants; all these are low values compared with the upper limits of 140 μg/m3 permitted by the “Technische Anleitung Luft”. It is worth mentioning in connection with the problems with present environmental protection that the per capita electricity consumption of private households has increased much faster than that of industry.
Alkalische Batterien für Elektrostraßenfahrzeuge – technische und wirtschaftliche Aspekte
Authors: Plust Heinz G.
Published: December 2004

Alkali batteries for electric vehicles – technical and economic aspects. The running of an electric vehicle places certain demands on the battery used as source of energy. An important factor is the relationship between storage capacity and good loadability. Of the battery systems currently under development it is found that alkali accumulators satisfactorily fulfil most of the important requisites. As a survey of these systems shows, alkali accumulators have now reached such a state of development that their employment in vehicles can be realistically discussed from the technical point of view. The systems Ni/Zn and Ni/Fe are the most promising, and economic considerations would suggest that alkali accumulators can be employed instead of lead/acid accumulators, even if the battery costs are relatively higher.
Technische und wirtschaftliche Überlegungen zur Elektrotraktion – VW‐Elektro‐Transporter
Authors: Kalberlah Adolf , Schimkat Harald
Published: December 2004

Technical and economic aspects of electrically powered VW commercial vehicles. The article first describes the “VW Electric Delivery Truck System”, consisting of the vehicle and the peripheral equipment to operate it, and then reports experience gained with this type of vehicle, of which more than 70 have been registered for operation on public roads since 1972. On the basis of these VW commercial vehicles, which are equipped with lead‐acid batteries, the authors discuss the potential advantages of using new types of batteries with twice the energy to weight ratio. The resulting vehicle versions and their total weights, payloads, battery weights, energy requirements, and operating costs are reviewed. It is shown that a considerably higher price for batteries with twice the energy/weight ratio would be acceptable under certain circumstances.
Creeping fronts and travelling waves
Authors: Aris Rutherford
Published: December 2004

Some of the ramifications of Wicke's work on creeping fronts in fixed beds are reviewed in this paper. His work laid the experimental foundations for model building by Vortmeyer and Jahnel on the one hand and by Amundson and Rhee on the other. These workers showed how slowly moving waves could arise in various models of these systems. The relation between such a creeping front and a travelling wave of fixed form is further discussed and some of the more recent biological applications are mentioned.
Konstruktive Lösungen zur Maßstabsvergrößerung von mehrphasig durchströmten Apparaten
Authors: Mewes Dieter , Dahm Franz Ludwig , Kurandt Uwe
Published: December 2004

Design approaches for the scaling‐up of multiphase flow apparatus. The scaling‐up of apparatus from the laboratory‐to the industrial‐scale is illustrated with aid of two examples. Phase partition during the flow of liquids and gases through packing layers is dealt with. It requires particular attention if the volumes of flow are different and if the efficiency of material exchange on an industrial scale referred to volume is to be the same as on a laboratory scale. A design approach for the uniform distribution of a small volume of gas in uniflow with a large volume of liquid is described. For counter‐current flow of large volumes of gas and small volumes of liquid an arrangement of packing with least possible drop in pressure is required. Some well‐known packings are compared, taking into account measured results for a novel packing referred to as “impulse packing”.
Strömungsturbulenz und Verbrennung
Authors: Günther Rudolf
Published: December 2004

Turbulent flow and combustion. Flame‐generated turbulence was long a topic of lively discussion. Since the hot gases arising on combustion are much more viscous than, e.g. cold air and cold natural gas, the Reynolds number of a flow system is more likely to fall. Indeed, combustion is observed to promote laminar flow at low Reynolds numbers. The concept of “flame‐generated” turbulence was imprecisely defined; a predominant thought was concerned with the turbulence‐reinforcing effect of combustion in an existing field of turbulent flow. Some authors doubted whether such an effect is possible. Meanwhile, it has been established that combustion can affect turbulent exchange in various ways, as demonstrated in this paper.
Hochdruck‐Polyäthylen
Authors: Luft Gerhard
Published: December 2004

Low‐density polyethylene. The constantly changing economic situation requires periodic re‐assessment of the general direction of process and product development. This contribution surveys the present state of the art of high‐pressure polyethylene synthesis with due consideration of recent developments. Starting from chemical and chemical‐engineering fundamentals, the various polymerization processes and their products are compared and contrasted, and an attempt is made to predict further developments.
Verfahrenstechnik für den Umweltschutz
Authors: Biedenkopf Gerhard
Published: December 2004

Industrial process engineering and environmental protection. Industrial process engineering involves not only the realization of chemical‐physical processes but also the optimization of the economics of a plant and the minimization of environment pollution. Since the incorporation of additional facilities in a process for the reduction of emission has been brought to a high technical standard in recent years, more and more attention will now be directed to achieving a high selectivity in favor of the product in the chemical reaction by suitable process control. It is shown with the aid of schematically represented mass balances and cost diagrams that emission can be reduced by process engineering optimization of a process, leading to a decrease in both the costs incurred from environmental pollution and the costs for the preventative measures taken.
Berstsicherheit von Chemie‐Apparaten
Authors: Gaube E. , Braubach H.‐O. , Dickhäser M.
Published: December 2004

Burstproofness of chemical apparatus. The first part of the paper deals with the safety requirements that have to be met by pressure vessels, the interaction of material behaviour and structural form, and the design principles in industrial codes. An important pre‐requisite for the avoidance of brittle fractures is material toughness also at those parts of the pressure vessels where increases in stress due to the shape of the vessels cannot be avoided. As a result of the development of new materials, the Dechema technical committee „Materials and design in the construction of chemical apparatus”︁ constituted the working party “Strength and toughness” in 1962 and assigned to it the task of carrying out bursting tests on model pressure vessels similar in size and shape to those used in practice, the purpose being to tudy the influence of material toughness and vessel shape on burstproofness. This study, which was completed early in 1979, is reported in the second part of this article.
Neuere Erkenntnisse und Anwendungen bei der elektrischen Abscheidung von Stäuben und Nebeltröpfchen
Authors: Mayer‐Schwinning Gernot , Rennhack Rolf
Published: December 2004

New insights and applications in the electrostatic precipitation of dusts and mists. The introduction deals with the basic design, the mode of operation, and the fields of application of dry and wet type electrostatic precipitators. A few important parameters which influence the migration velocity are discussed. Contrary to what the classical theory states, greater passage widths lead to higher migration velocities of the particles and thus to a higher specific efficiency. The methods for conditioning flue gases of power stations are considered, as are the experimental results obtained in an industrial‐scale SO3 conditioning plant. A new field of application is seen in the steel industry through the use of a dry type electrostatic precipitator of special design. New plastic precipitator developments for the chemical industry are discussed, and the articles closes with an account of the efforts invested in developing hot gas precipitators for higher temperatures and pressures in connection with the introduction of new power station concepts.
Erste fernbediente, vollautomatisierte Verdichterstation für Ethylen in Deutschland
Authors: Borner Joachim , Braun Rainer , Nieding Walter
Published: December 2004

First remote‐controlled, fully automated ethylene compressor plant in Germany. The Hoechst company has been operating an ethylene pipeline between Cologne and Frankfurt‐am‐Main since 1960. The capacity of this pipeline had to be increased from 250 000 t/a to 350 000 t/a, and this is why a remote‐controlled fully automated ethylene intermediate compressor came into operation in 1978. The unmanned station was constructed as a grass roots project with ancillary and safety displays and is controlled and monitored from an 80‐km distant control desk. Compression is by two piston compressors arranged in parallel, with each one accounting for 50% of the throughput capacity. Particular attention was paid to the safety concept of the station. All interlocking systems necessary and possible manual operations are permanently wired. The start‐up and shut‐down programs are located in a freely programmable control system. Such stations can be constructed from prefabricated units in inaccessible areas.
Wärmeübergang in Rührkesseln mit mehrphasigen Systemen
Authors: Steiff Artur , Poggemann Reinhold , Weinspach Paul‐Michael
Published: December 2004

Heat transfer in agitated vessels with multiphase systems. Heat transfer behaviour in agitated vessels with gas liquid, liquid liquid, solid liquid, and solid gas systems is analysed and presented on a similarity theory basis. Experimental results and proposed methods of calculation given in the literature are compared critically; the subject of scaling‐up is also dealt with. The present paper is restricted to simple multiphase systems with Newtonian and non‐Newtonian flow behaviour. In the case of complex multiphase systems, as are often met with in practice, i e. systems with kneadable or pasty consistency with significant separation, creaming, or settling phenomena, or with a tendency to incrustate, further investigations are necessary, taking into consideration the results already given in the literature. Working equations presently available for the calculation of indirect heat transfer in agitated vessels with gas/liquid, liquid/liquid, solid/liquid, and gas/solid systems have been collected in tables; these can be ordered from the „Lehrstuhl für Thermische Verfahrenstechnik”︁, Universität Dortmund, Postfach 500 500, D‐4600 Dortmund 50.
Kristallisation aus Schmelzen
Authors: Matz Günther
Published: December 2004

Crystallization from melts. Equipment for crystallization from melts differs considerably from the solution crystallizer. The article discusses: Trough crystallizers, belt crystallizers, pastillators, flakers, screw crystallizers, and prilling towers. The kinetics of melt crystallization is simpler than that from solution, and the secondary nucleation becomes less important. Environmentally, crystallization from melts is more attractive because absence of solvent obviates waste products. Dust problems are avoidable by flaking, pastillizing, and prilling.
Eigenschaften hochtemperaturhydrolytisch hergestellter Kieselsäuren und Metalloxide für Katalysatoren
Authors: Koth Detlev , Ferch Horst
Published: December 2004

Catalytic properties of silicic acids and metal oxides prepared hydrolytically at high temperatures. The physical and chemical properties of silicic acids and metal oxides (Al2O3 and TiO2 P25) prepared hydrolytically at high temperatures are described, insofar as they might be of interest to catalyst producers. A highly topical literature survey reveals areas of interest in the fields of research and practical applications. The experimental section deals with the preparation of catalyst supports made of highly dispersed silica gel products. Their characteristics are tabulated.
Anfahr‐ und Betriebsverhalten von exothermen Batch‐Prozessen
Authors: Hugo Peter
Published: December 2004

Start‐up and operation of exothermic batch processes. A survey of the general characteristics of batchwise chemical production processes shows that the possibilities of complete prediction of optimum production tactics are limited. Thus recourse is taken to simplified semi‐empirical design procedures. It is demonstrated in the case of exothermic batch processes with indirect cooling that criteria can be given as to whether this production strategy is technically feasible. Given technical feasibility, these criteria can be used for design of a safe start‐up and operating behaviour. The procedure is illustrated for two applications.
Der Sicherheitsaspekt beim Eintrag von Schüttgütern in Behälter
Authors: Simon Eberhard
Published: December 2004

Safety aspects of charging bulk material into vessels or containers. The safe charging of bulk material requires a careful analysis of the potential sources of danger which can result from the physical properties of the materials and the design and construction material of plant and equipment. The method adopted in this analysis is illustrated and explained for selected examples. Criteria for safe charging methods are compiled and explained. A selection of proven charging equipment is listed and technically evaluated with respect to safety and operating criteria. Steps that must be taken to avoid charging errors are discussed. Special problems encountered on connecting pressureless charging devices to pressure vessels are outlined explained. The utilization of inert gas as a preferred method of explosion protection is discussed. Various methods are compared, and their application to special problems in charging bulk material is illustrated.
Verbesserte Kostenschätzungen durch Anwendung von Mengen‐ und Mannstunden‐Verhältniszahlen
Authors: Groen B. , Tan K. D.
Published: December 2004

Improved cost factor estimation with quantity and man‐hour ratios. Present‐day cost estimation on a multi‐currency basis is becoming more and more complex due to the wild and frequent fluctuations of exchange rates and different inflationary trends in various countries. The preparation of comparatively accurate preliminary cost estimates, based on world‐wide procurement, overseas construction and engineering, became a major problem for companies like badger with international activities. To maintain an acceptable degree of accuracy, the traditional method of cost factor estimation has to be supplemented with a quantity and man‐hour ratio method. Basically, costs are related to quantities; therefore cost ratios can be converted into quantity ratios. Man‐hour ratios originate from the existing relationship between quantities, material costs, and field man‐hours to install these quantities. In this article the value of the Quantity Ratio Method as a tool in these unstable times will be stressed, as well as the added advantages it offers with regard to better cost control and communication.
Zum Flutpunkt in Flüssig/Flüssig‐Gegenstromkolonnen
Authors: Mersmann Alfons
Published: December 2004

Flooding point of liquid‐liquid countercurrent columns. Calculation of the column diameter for given volumetric flow rates of the raffinate and the extract phases requires a knowledge of the flooding point. A simple flooding point diagram is presented which contains the rise or fall rate of an individual drop as intermediate quantity. The principal experimental results from the literature obtained in countercurrent columns with and without introduction of energy by rotation and pulsation are compared with the flooding point diagram.
Standortgefertigte Druckbehälter
Authors: Straub Hermann
Published: December 2004

Das Arbeitsgebiet der standortgefertigten Druckbehälter ist so umfangreich, daß eine vollständige Übersicht weit über den Rahmen eines einzigen Beitrages hinausgeht. Es werden daher vorwiegend Kugeldruckbehälter für verdichtete oder verflüssigte Gase behandelt. Andere große Druckbehälter wie Reaktoren und Sicherheitshüllen werden nur am Rande erwähnt. Dabei interessieren in erster Linie der Stand der Technik sowie die damit verbundenen Probleme und Entwicklungstendenzen und dies nicht zuletzt im Hinblick auf das ständig wachsende Sicherheitsbedürfnis der Bevölkerung gegenüber der Technik.
Flüssigphase‐Rückvermischung in gepackten Blasensäulen
Authors: Gestrich Wolfgang , Harth Hubert
Published: December 2004

Für die Flüssigphase‐Rückvermischung in mit Metallraschigringen und ‐pallringen gepackten Blasensäulen werden Korrelationen für den axialen Dispersionskoeffizienten in der Form Peg = f (Ga, Reg, H/D) angegeben. Die Einzelabhängigkeiten von Stoff‐ und Betriebsgrößen werden anhand von Diagrammen ausführlich erläutert. Pallringe vermögen in Säulen mit Durchmessern D > 20 cm Großwirbel und Rückvermischung nur unvollkommen zu unterdrücken. Auch für diesen Bereich wird eine Faustformel für den scheinbaren Dispersionskoeffizienten angegeben. Dagegen sind Raschigringe zur Unterdrückung der Rückvermischung gut geeignet. Es wird auf die Problematik von Modellerfüllung und störungsfreier Messung der Rückvermischung eingegangen.
Perspektiven für die Forschung im Chemieingenieurwesen: Die französische Politik
Authors: Villermaux Jacques
Published: December 2004

Die französische Regierung hat vor einigen Jahren einen Ausschuß gegründet, um zu bestimmen, welche Forschung in der Zukunft auf dem Gebiet des Chemieingenieurwesens in Frankreich betrieben werden soll. Das Ergebnis dieser Überlegungen wird hier vorgestellt. Zuerst wird der jetzige Stand der französischen Forschungsinstitute kurz beschrieben: Programme, Struktur, Finanzierung und Zusammenarbeit mit der Industrie. Im zweiten Teil werden die Probleme beschrieben, die sich in einer technisch orientierten Gesellschaft stellen, bei deren Lösung das Chemieingenieurwesen seinen Beitrag leistet. Die bei der Übertragung chemischer Verfahren vom Labor‐ zum technischen Maßstab erzielten Erfolge werden hervorgehoben, die folgenden Schwerpunkte werden genannt: systemtheoretische Vorgehensweise, Modellierung zur schnellen und sicheren Auslegung, schnelle Anpassung der Verfahren bei sich ändernden wirtschaftlichen Randbedingungen, Ausdehnung der im Chemieingenieurwesen üblichen Begriffe auf andere Gebiete (Biologie, Lebensmittel‐ und Bodentechnik, elektrochemische, Sonnen‐ und Kernverfahrenstechnik usw.). Noch ungelöste Probleme und zukunftsträchtige Forschungsthemen werden vorgestellt: Wärme‐ und Stoffaustausch in Mehrphasensystemen, exergetische Prozeßanalyse und Ursachen des Exergieverlusts in Einheitsverfahren, neue Trennverfahren und Reaktortypen, Verfahren mit regenerierbaren Rohstoffen, Automatisierung der Prozeßfüfhrung.
Energieeinsparung in der Verfahrenstechnik
Authors: Arnold D. , Bartmann L.
Published: December 2004

Energiekosten sind für Wärmeprozesse in der chemischen Industrie bekanntlich ein wesentlicher Kostenfaktor. Seit der beträchtlichen Preissteigerung der Primärenergieträger sind weltweit Bemühungen im Gange, die spezifischen Energiever‐brauchszahlen bei der Herstellung chemischer Produkte zu senken. Im ersten Teil der Arbeit werden theoretische Überlegungen über Möglichkeiten der Energieeinsparung in der chemischen Industrie angestellt. Stark im Vordergrund steht das Bestreben, bei der Durchführung von Prozessen möglichst wenig Primärenergie einzusetzen. Besondere Schwerpunkte sind thermodynamische Betrachtungen von Wärmepumpen, mehrstufigen Prozessen sowie der möglichen Integration von Gegendruckkraftwerken in einem Chemiekomplex. Im zweiten Teil der Arbeit werden anhand geplanter und praktisch ausgeführter Beispiele konkrete Hinweise auf Energieeinsparungen gegeben. Hierbei wird berücksichtigt, daß während der letzten Jahre die relative Preissteigerung von Primärenergien größer ist als die von Investitionsgütern.
Vorausberechnung von Flüssig/Flüssig‐Gleichgewichten
Authors: Arlt Wolfgang , Grenzheuser Peter , Sørensen Jens Mourits
Published: December 2004

Die Kenntnis des Phasengleichgewichts der beteiligten Stoffe ist für die Auslegung von Extraktionsanlagen von wesentlicher Bedeutung. Während man sich früher auf empirische und halbempirische Verfahren stützen mußte, gelingt heute die Berechnung von Flüssig/Flüssig‐Gleichgewichten mit Modellen aus der molekularen Thermodynamik. In diesem Übersichtsartikel werden Datenquellen, Berechnungsgrundlagen und Methoden zur Berechnung polynärer Flüssig/Flüssig‐Gleichgewichte behandelt sowie Resultate und Genauigkeit der modernen Methoden verglichen.
Grundlagen einer sicheren Chemieproduktion
Authors: Lippert Axel , Pilz Volker
Published: December 2004

Schrittweises Vorgehen und ständig wiederkehrende Überprüfungen sowie systematische Störungsanalysen sind wesentliche Elemente bei Entwicklung, Planung und Betrieb sicherer Chemieanlagen. Das läßt sich anhand der grundsätzlichen Vorgehensweisen überzeugend darlegen. Die Diskussion einiger Methoden der systematischen Sicherheitsanalyse und ihre Anwendung auf ein einfaches Beispiel machen andererseits die Grenzen sicherheitstechnischer Maßnahmen deutlich. Die Sicherheit im Chemiebereich ist im Planungsstadium nicht zu quantifizieren. Wohl aber läßt sich durch Hinweis auf alle bisherigen Erfahrungen zeigen, daß nach dem Stand der Technik errichtete Chemieanlagen ausreichend sicher sind.
Gedanken zur Qualitätssicherung beim Bau von Chemieanlagen
Authors: Gräfen Hubert , Gerischer Karl
Published: December 2004

Um eine Chemieanlage gefahr‐ und störungsfrei betreiben zu können, ist eine Vielzahl von Maßnahmen zur Qualitätssi‐cherung bei der Planung, während des Baus und im Betrieb notwendig. Anhand eines Beispiels, nämlich eines großen Reaktors, werden diese Maßnahmen geschildert. Dabei wird besonders auf die einzelnen Bauphasen und die zwischenge‐schalteten zerstörungsfreien Prüfungen eingegangen, berührt werden aber auch die Qualitätsplanung, die Qualitätssiche‐rung im Betrieb und die Organisation des Qualitätswesens. Das Beispiel soll zeigen, daß noch so viele Qualitätsdokumentationen die Bereitschaft der beteiligten Menschen, qualitäts‐gerecht zu arbeiten und für die Güte der eigenen Leistungen einzustehen, nicht ersetzen können. Deshalb muß die Erziehung zum Qualitätsdenken eine wichtige Aufgabe der Qualitätssicherung sein.
Systematische, überbetriebliche Entsorgung von Abgas‐ und Abluftströmen aus chemischen Produktionsbetrieben (Ein Beitrag zum Umweltschutz)
Authors: Hagenberg Peter , Jordan Anton , Lorenz Hans
Published: December 2004

Die steigenden Anforderungen an den Umweltschutz und die sich immer wieder verschärfenden gesetzlichen Regelungen erforderten Ende der 60er, Anfang der 70er Jahre für das Werk Dormagen der Bayer AG ein neues Konzept für die Entsorgung von Abgas‐ und Abluftströmen aus den Produktionsbetrieben.

Die speziellen Bedingungen des Werkes Dormagen führten zu einem Konzept, dessen Schwerpunkt in der Sortierung von Abluftströmen und deren thermischen Verbrennung in zentralen Verbrennungsanlagen und Kraftwerken bildet.

Nach mehrjähriger Entwicklung und Ausbau der Anlagen wurde ein Standard erreicht, der es gestattet, schwierige Produktionen auch hinsichtlich der Abluft problemlos zu betreiben.
Der Verfahrensingenieur in der Chemischen Industrie
Authors: Bogenstätter Günter , Frey Walter
Published: December 2004

Die wesentlichen Aufgaben und Tätigkeiten der Verfahrensingenieure in der chemischen Industrie lassen sich in vier große Bereiche einteilen, die oft auch organisatorisch zusammengefaßt sind: Die Versuchs‐ und Entwicklungsingenieure befassen sich mit der Prozeßentwicklung und der Betreuung der chemischen Forschung sowie mit der Entwicklung im Rahmen der verfahrenstechnischen Grundoperationen. Aufgabe der Anlagenbauingenieure ist der Bau von Produktionsanlagen einschließlich vorbereitender Studien. Die Betriebsingenieure sind für die Erhaltung des technischen Standes der Produktionsanlage verantwortlich.

Charakteristisch für die Tätigkeit der Verfahrensingenieure in der chemischen Industrie ist darüber hinaus die Fülle von nichttechnischen Aufgaben, die im Rahmen der Ingenieurtätigkeit zu bewältigen sind. Im Vordergrund steht dabei die Beachtung wirtschaftlicher Fragestellungen. Zu den wichtigen Nebenaufgaben gehört auch die Berücksichtigung gesellschaftlicher Umweltbedingungen, seien sie nun gesetzgeberischer, sozialer oder menschlicher Art. Derartige Kenntnisse und Fähigkeiten werden normalerweise nicht im Rahmen der Ausbildung an der Hochschule vermittelt, sondern müssen im Betrieb selbst erarbeitet werden.

Für die kommenden Jahre ist mit einem zunehmenden Bedarf an Verfahrensingenieuren in der chemischen Industrie zu rechnen. Die Zahl der Hochschulabgänger auf diesem Arbeitsgebiet ist jedoch seit mehreren Jahren nahezu konstant und wird sich voraussichtlich in absehbarer Zeit nicht ändern.
Zur Praxis der schalltechnischen Planung von Chemieanlagen
Authors: Dövener Dierk
Published: December 2004

Zur Planung von Chemieanlagen ist es heute erforderlich, sich von Anfang an auf die aus der Anlage zu erwartenden Geräusch‐Emissionen einzustellen. Der Zwang zur Einhaltung vorgegebener Immissions‐Richtpegel in der Nachbarschaft verlangt eine frühe und enge Zusammenarbeit zwischen Anlagenplaner und Akustiker bei der Auswahl und Anordnung von Maschinen und Apparaten. Um die Auswirkung auf die Geräusch‐Emission des Werkes bei Ersatz alter Anlagen durch Neuanlagen auf beschränktem Areal, was bei den großen chemischen Werken der Fall ist, zu erfassen, sind Rechenmodelle zweckmäßig, die im Rahmen der allgemeinen Werksplanung zuverlässige Vorhersagen über die zukünftig zu erwartenden Immissionspegel zulassen.