bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sortieren von Mineralsalzen nach spezifischen Eigenschaften
Authors: Singewald Arno 
Published: December 2004

AbstractSeparation of mineral salts on the basis of specific material properties. This survey explains how different specific properties which are „inherent”︁ to the material, such as density, magnetizability, and conductivity, can be utilized to separate mixtures of solids into individual components. As for salt minerals, the differences in their physical characteristics are very small and mostly not significant enough to allow a technical separation. Therefore the selective leaching based on the difference in hydration of the crystal components (ions) has been the predominant process. However, the selective dissolution of a specific type of salt and its subsequent recrystallization requires a high energy input and leads occasionally to environmental problems. It is for this reason that the mechanical procedures of „flotation”︁ and „electrostatic separation”︁ (ESTA‐process) have meanwhile become interesting alternatives. In these processes specific surface properties, i. e. „external”︁ properties, are used for the separation. Non‐utilizable residual liquids, which often occur in the dissolution process and result in waste water problems, can thus be avoided. The principle of these two separation procedures as well as their application to the refinement of crude salts containing potassium and magnesium are described.
Pulvermetallurgische Bauelemente in der Verfahrenstechnik
Authors: Fischer Axel , Arnhold Volker 
Published: December 2004

AbstractPowder‐metallurgical components in process engineering. Applications of structural parts made by powder metallurgy can be found in nearly all kinds of industries, especially the automotive industry, and the electrical and electronics industry. This paper describes applications of porous P/M materials for chemical technologies. Quite well known are sintered metal filter elements of different sizes in the form of tubes, plates, and cartridges. Porous P/M materials can also be used as flame resistors and silencers, for the dispersion of gases in liquids, for drying processes, and for homogenisation of various products. Almost all technically interesting alloys are available for these elements. New applications for porous metal structures are under development for the use of catalytically active reactor beds in solid bed reactors. It was found that some reactor bed materials are themselves active as catalysts. In such a reactor, the temperature gradient is very small, so that chemical reactions can be controlled much more efficiently.
Meß‐ und Dosiertechnik beim Betrieb von Miniplants
Authors: Schulz‐Walz Axel 
Published: December 2004

AbstractMeasuring and metering technology in the operation of mini‐plants. The technology of measuring and metering in mini‐plants differs considerably from that in production plants. The number of measuring points is greater, the process control system has to be more flexible, and the actuators, sensors, and metering devices require small construction methods. Examples taken from the author's experience serve to illustrate this situation.
Das Zerstäuben als Grundverfahren
Authors: Bauckhage Klaus 
Published: December 2004

AbstractAtomization as a unit process. Liquid atomization can be classified by three successive steps: disintegration; multiphase flow in the spray; and impact of droplets on the substrate. The most important process parameter is the size distribution of the droplets. By means of this parameter the liquid disintegration process can be related to the different transport phenomena in the spray or to the impacting process. The size distribution of the droplets is not a static parameter but an evolving result of local changes depending on sifting effects, on strand formation, on coalescence, on evaporation, on drying or chemical reaction processes. It is thus essential, for further analysis, to start from local instead of integral size distributions. This will be possible because of the efficiency of new particle sizing instruments with high spatial or temporal resolution. This opens the possibility for differential instead of integral balance. From this one can derive, for the future, higher precision of apparatus design and improved optimization procedures for process design. Finally, appropriate measuring techniques are discussed with regard to their special applicability to liquid atomization analysis.
Instationäre Reaktionsführung zur Modellierung heterogen katalytischer Reaktionen
Authors: Renken Albert 
Published: December 2004

AbstractTransient processes in modelling heterogeneous catalytic kinetics. It is often difficult to obtain mathematical models to describe the dynamics of heterogeneous catalytic reactors. Kinetics determined under steady‐state conditions are normally not valid for the transient behaviour of catalytic reactions. In order to find valid kinetic models, information is needed about the adsorption‐desorption processes and the formation of intermediates on the surface. To get single step models, experiments have to be carried out under transient or oscillatory conditions. This is discussed for different examples taken from the literature.
Sicherheitsanalytische Vorgehensweise für Alt‐ und Neuanlagen
Authors: Ruppert Kurt Alfred 
Published: December 2004

AbstractSafety analysis approach to existing and new plant. Technical advances and steadily increasing knowledge, as well as the extension of breakdown ordinances, call for more rational systematic approaches in order to master the current volume of necessary documentation. During development to operational maturity, including modification of plant and processes, various internal and external interdisciplinary teams are involved in setting up and evaluating the safety measures. A comprehensive procedure was therefore developed for new and existing plant which should optimally satisfy demands for clarity, systematic structure, openness for individual process steps, and facilities for updating data.
Wäßrige Stoffsysteme zur Absorption von SO2
Authors: Meckl Stefan , Wunder Rainer 
Published: December 2004

AbstractAqueous absorbents for absorption of SO2. The removal of SO2 from flue gases is dominated by processes of absorption with aqueous absorbents. Aqueous systems are favourable in contrast to organic absorbents because the water vapour contained in the flue gas does not interfere with the separation. The transport of gaseous SO2 into the liquid phase and the subsequent transformation into sulfite/bisulfite or sulfate after oxidation is typical for the aqueous processes of absorption. Starting from water as absorbent the addition of various basic agents makes an increase in the absorption capacity of the washing solution possible by several orders. Different solubilities of the agents or the resulting compounds, the dependence of the vapour pressure on the concentration and desired and undesired reactions determine the thermodynamics of the processes. The regenerative sodium salt processes as the Wellman‐Lord (sodium sulfite) process, the Flakt‐Boliden (sodium citrate) process and the sodium phosphate process, the regenerative ammonium sulfite process, the processes producing gypsum and the absorption with oxidation to sulfuric acid are noted. The advantages and limitations of the particular processes are pointed out by means of the vapour liquid equilibria, the solubilities of the salts and the oxidation reactions.
Abscheidung und Messung sehr feiner flüssiger und fester Partikeln in der chemischen Industrie
Authors: Bürkholz Armin 
Published: December 2004

AbstractSeparation and measurement of very fine liquid and solid particles in the chemical industry. In comparison to power stations, the total amounts of waste gases emitted by the chemical industry are fairly low. On the other hand, the complexity of the waste gases and their components is far higher. In the chemical industry we can therefore not be content with one overal concept for gas purification, but must use a multitude of individual solutions. These should be applied at source, i.e. to each separate production plant. To solve an aerosol separation problem successfully and economically, a knowledge of the composition, the fineness and the amount of aerosols is essential. Cascade impactors have proved to be the most suitable instruments for a fractionated measurement of solid and liquid particulates in the super and sub‐micron size range. The results of these measurements make is possible to choose the right equipment and to calculate its performance. Very complex aerosols, e.g. aerosols which are composed both of liquid and solid particles, or of sticky particles, are likely to present the most difficult problems. This article deals with a small selection of cases by demonstrating the problems of separation and the different ways of solving them. It considers among others acid mists and oil mists as well as organic mists, together with very fine particulates from waste incineration plants.
Biologische Denitrifikation nitrathaltiger Abwässer und Grundwässer
Authors: Lompe Dieter , Wiesmann Udo 
Published: December 2004

AbstractBiological denitrification of nitrate‐containing waste water and ground water. The differing objectives serve to distinguish processes for the treatment of waste water and those for the production of drinking water. In waste water purification, frequent use is made of submerged reactors with deposition and recycling of bacteria. The carbon compounds required by the bacteria are either present in the water or have to be added. If the nitrogen is present as ammonium in the waste water, then there are several different ways of combining nitrification and denitrification reactors. In production of drinking water, both heterotrophic and autotrophic bacteria are used. Since the bacteria are not allowed to enter the supply network, fixed reactors or other reactors with immobilised biomass are used. Sand bed filters are still necessary to retain compounds from the water after denitrification.
Meß‐ und Rekonstruktionsmethoden für tomografische Messungen
Authors: Mewes Dieter , Renz Rudolf 
Published: December 2004

AbstractMethods of measurement and reconstruction for tomographic records. Tomographic measuring methods are being used more and more frequently in process engineering studies. This technique permits contactless and reactionless measurement of concentration, temperature, and velocity fields. The measuring methods used in tomography are explained in this article. In addition, the paper also considers mathematical methods for the reconstruction of measured field quantities and examines their quality of reconstruction. Numerous applications of tomography are cited.
Die zirkulierende Wirbelschicht als Reaktionssystem für katalysierte Gas/Feststoff‐Reaktionen
Authors: Herrmann Erhard , Weisweiler Werner 
Published: December 2004

AbstractThe circulating fluidized bed reactor for catalyzed gas/solid reactions. For many years circulating fluidized beds (CFB) have been successfully employed for a variety of technical applications, e.g. for dry sorption processes to clean waste gases from alumina electrolysis, waste incinerators, and from coal dust combustion. A new application of the CFB principle, the dry and simultaneous removal of nitrogen oxides and sulfur oxides both from power plant and industrial waste gases has been developed and tested in laboratory‐scale, bench‐scale, and pilot plant facilities and has since reached technical maturity. In this dry DeNOx/DeSOx process, desulfurisation is accomplished by dry sorption with Ca(OH)2 whereas NOx is eliminated by selective catalytic reduction (SCR) with NH3 as reducing agent. To perform the process in a CFB reactor, powder‐like DeNOx catalysts are required. Referring to the simultaneous DeNOx/DeSOx CFB‐process, the main features of highly expanded gas/solid reaction systems as well as the requirements for fine catalyst particles used therein are evaluated. First basic results of the simultaneous NOx und SOx removal from firing gases in the CFB will be reported.
Optische Sensoren für die Bioprozeß‐Kontrolle
Authors: Dremel Bernd A. A. , Schmid Rolf D. 
Published: December 2004

AbstractOptical sensors for bioprocess control. Bioprocess techniques are an important field in biotechnology. To run processes with high yields of products, to ensure product quality and for process optimization it is essential to acquire relevant process and control parameters quickly with high reliability. Therefore, various types of sensors are used; recently, beside chemosensors, new emphasis has been placed on biosensors for bioprocess control. At the same time optical transducers are gaining in significance. One reason for the increasing interest in optical sensors is the ready availability of fiber optic technologies. The combination of sensor technologies with fiber optics offers many possibilities due to miniaturisation and remote control and therefore meets the special requirements of bioprocess techniques. This review introduces various classes of optical chemo‐ and biosensors for bioprocess control.
Simulatoren zur Unterstützung der Prozeß‐ und Betriebsführung
Authors: Holl Peter , Schuler Hans 
Published: December 2004

AbstractSimulators for support of process and plant management. Process simulators are increasingly used for plant and process operation purposes. These simulators differ from those used in process design in the user interface, which is identical to the usual operator interface of distributed control systems. The progress of the numerical solution parallels the dynamic behaviour of the real process, and not that of the numerical procedure. The simulation‐supported tasks of plant and process operation are: education of operators, training and instruction of operators, support of plant operation by interpretion of plant states and transitions and by helping to formulate operating instructions. These tasks, the available simulation concepts and examples are discussed in detail.
Bewertung von Füllkörpern und die Grenzen ihrer Weiterentwicklung
Authors: Billet Reinhard 
Published: December 2004

AbstractEvaluations of Packings and the Limitations of their further Development. The performance of a newly developed packing can generally only be determined experimentally. Tests can be carried out to find the dependence on geometry, load and physical properties of the system, a knowledge of which is required to develop a physical model. Such a model then enables description of the fluid dynamic behaviour and the effectiveness of mass transfer within packed columns and their dimensioning. The model also clearly indicates the possibilities and limitations of further development of packings. Practical examples will confirm the theoretical considerations.
Vorgehen bei der Trocknerauswahl
Authors: Schultz Peter , Hilligardt Klaus 
Published: December 2004

AbstractSelection Procedure for Dryers. Many different dryers have been developed in the past because of strongly varying drying behavior and widely changing consistency of the drying products. Therefore, a strategy to select the most appropriate dryer for a given problem is needed in order to minimize the cost of process development. A selection procedure consisting of seven steps is presented in this paper. Applying this procedure, a uniform and reproducible selection is obtained.
Abschätzung des Gefährdungspotentials druckverflüssigter Gase
Authors: Strohmeier Klaus 
Published: December 2004

AbstractEstimation of Potential Danger Arisig from Pressure‐Condensed Gases. Analytical solutions are shown for a specific industrial application in order to estimate the potential danger of pressure condensation of gases. First of all it should be determined in which positions high stresses have to be expected. Afte excluding the case “Bruch vor Leck” (breakage before leak), possible cross sections of leakages can be stated. The laws of thermodynamics laws can be used to determine quantities pertaining to the states of aggregation concerned (liquid/gaseous) may be determined in case of failure. Finally it is possible to determine the size of the ground cradle as well as possible undergrate firing by an investigation of the processes at the liquied pools. Finally we indicated a water sprinkling plant sufficient for handling cases of fire. It was taken into account that the total heat of combustion of the leakage stream will be transferred to the cooling water film.
Berechnungsansätze zur Crossflow‐Filtration
Authors: Ripperger Siegfried 
Published: December 2004

AbstractCalculation of Crossflow Filtration. Crossflow filtration is the most widely used dynamic filtration process. The suspension to be filtered constantly flows over the filter medium. This counteracts formation of a filter cake and the height of the cake is limited. Reliable design of equipment still relies on the results of laboratory and pilot studies. Increasing use in practice has led to the development of approaches to the calculation of crossflow filtration which are reported in this article.
Kreislaufreaktor mit Konzentrationsregelung
Authors: Löwe Arno , Schnitzlein Klaus 
Published: December 2004

AbstractThe Concentration‐Controlled Recycle Reactor. The scope offered by the concentration‐controlled recycle reactor for elucidatin the kinetics of heterogeneous gas reactions is presented in three contexts: identification of reaction networks; experimental design; and separate determination of changes of activity. Control strategies appropriate for the problem at hand are an essential prerequisite for the application of experimental strategies. In particular, long analysis cycles require appropriate modification of modern methods of control theory. Various model‐based control concepts have been developed and tested by experiment and simulation.
Zirkulationsströmungen und die Vermischung der kontinuierlichen Phase in Blasensäulen
Authors: Millies Marco , Mewes Dieter 
Published: December 2004

AbstractCirculatory Flow and Mixing of the Continuous Phase in Bubble columns. Bubbles columns are widely used as reactors and mass transfer equipment between gas and liquid or solid phases in many areas of the materials‐transforming industry. The results known from theoretical and experimental research on flow and mixing of the continuous liquid phase and the relative gas content in bubble columns having diameters up to 0.30 m are presented. Evidence is presented for stable circulatory flow. The field of flow of the two phases is then described with the aid of mass and momentum balance equations. These are solved simultaneously by an analytical and a numerical procedure. Non‐linear flow instabilities in the form of several circulation cells are demonstrated as a result of the calculation. In the field of flow of circulation cells the local gas content increases towards the centre of the cell. This is a second‐order fluid‐dynamic effect which has so far eluded description in two‐phase flow using the numerical calculation techniques applied hitherto. The results provide the first possibility of calculating several circulation cells. Theoretical prediction of mixing the continuous phase and the transition from the homogeneous to the heterogeneous flow state in a semi‐industrial scale bubble column has thus become possible.
Teilen und Trennen im Recycling‐Prozeß
Authors: Melchiorre Michele , Güldenpfennig Martin , Löhr Karsten , Zürn Jörg 
Published: December 2004

AbstractDivision and Separation in the Recycling Process. The recycling process comprises a preparation and a reutilization step. This article describes preparation processes which are of importance for the recycling of used products and production wastes. The goal is to provide a clear presentation of the individual processes of division and separation and their mode of functioning with the aid of the systematic classification discussed in the paper. This is important for the overall process of recycling since combinations of various processes are usually employed. A systematic classification thus also provides a basis for new processes and combinations of processes.
Integrierte biotechnologische Produktionsprozesse
Authors: Schügerl Karl , Kretzmer Gerlinde , Freitag Ruth , Scheper Thomas 
Published: December 2004

AbstractIntegrated Biotechnological Production Processes. Manufacturing processes for ethanol and butanol are investigated with respect to reduction of product inhibition by integration with reversed osmosis, pervaporation, extraction, adsorption, flash evaporation, vacuum evaporation, and gas stripping. The integration of lactic acid formation with precipitation, extraction, electrodialysis, ion excange, and crystallization are considered. Adsorption, extraction and crystallization are examined as possible integrated recovery processes for antibiotics production. The possible future integrated use of adsorption, chromatography, membrane chromatography, extraction and flotation for protein production processes is discussed.
Einsatz von Enzymen und Antikörpern in organischen Lösungsmitteln
Authors: Stöcklein Walter F. M. , Scheller Frieder W. 
Published: December 2004

AbstractApplication of Enzymes and Antibodies in Organic Solvents. This review outlines the influence of organic solvents on antibodies, enzymes and their reactions, the different kinds of enzyme‐solvent systems, the various advantages of organic solvents compared with water and how they can be used for synthetic and analytical purposes. Main applications are the enzymatic synthesis of optically pure organic chemicals used as drugs, research chemicals, dyes or fragrants, as well as the analysis of hydrophobic compounds. Examples can be given of bioconversions in organic media by microbial cells and of syntheses with catalytic antibodies. Moreover, the full biotechnological potential of chemically or genetically engineered enzymes can only be exploited if the diversity of possible media is taken into account.
Zum Automatisierungsgrad von verfahrenstechnischen Prozessen
Authors: Schuler Hans 
Published: December 2004

AbstractRemarks on the Degree of Automation of Chemical Processes. In the discussion of lean production, the degree of automation is very often called into question. Overengineering of automation functions is often presupposed. In order to rationalize this discussion, this contribution outlines the broad spectrum of automation functions, automation principles and automation structures. On this basis, terms like the degree of automation, the connectivity of automation function, etc. are defined. These terms build the basis of the adequate choice of the degree of automation. Factors determining this choice and its consequences are described.
Kombination von mechanischer und thermischer Trocknung
Authors: Thurner Franz 
Published: December 2004

AbstractCombination of Mechanical and Thermal Drying. The first part of this paper presents the various hardware approaches to combining mechanical and thermal drying. The various solutions are illustrated by applications. The second part addresses cost optimisation in the combination of mechanical and thermal drying. The approach to cost optimisation is illustrated for the example of corn starch.