bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sicherheitstechnische Beurteilung von Trocknungsverfahren in der chemischen Industrie
Authors: Maurer Bodo , Riede Thomas 
Published: December 2004

AbstractSafety Engineering Assessment of Drying Processes in the Chemical Industry. Dried products encountered in the chemical industry are frequently flammable and susceptible to dust explosions. Moreover, some of the products to be dried contain flammable solvents. Since the two product states moist and dry co‐exist in a drying process, the dry potenially explosive solid, flammable solvent vapours, and fuel gases could all be present in a drying plant. A comprehensive safety engineering assessment of the entire drying process is therefore absolutely essential in the planning of new plant and in the examination of existing plant. The starting point and basis of safety engineering assessment is a knowledge of just a few characteristic safety data. If these are known then a decision can be made whether safety measures are necessary and if so what measures can asure safe operation of a plant. This contribution describes the approaches adopted in deciding upon such measures. Recent developments in the area of safety assessment of flammable dusts are included. An example is then presented to illustrate how the joint efforts of experts in the fields of safety engineering and drying technology can assure optimum plant safety, product quality, and cost‐effectiveness.
Wasserstofftechnologie für Antriebssysteme mit Zukunft
Authors: Tachtler Joachim 
Published: December 2004

AbstractAlongside constant optimisation of conventional motors, BMW has long been conducting basic research on the use of new energy sources and drive systems having significant advantages with respect to emission levels and availability of resources. Electricity stored in batteries or in the form of hydrogen hold considerable promise in the long term. During the present decade, electrically powered cars come into question for short runs; these are characterised by higher efficiency if certain conditions relating to the overall energy balance are met. Significantly greater action radii are possibly only with liquid hydrogen. Although the engineering questions and factors such as storage, safety, and handling can be regarded as basically solved, use of hydrogen‐powered vehicles will initially be in niche areas because of the lack of infrastructure. Hybrid systems to compensate for battery risks and charged with natural gas stored in gaseous (CNG) or liquid form (LNG) will serve important pioneering functions. BMW will market natural gas‐driven vehicles from the end of 1995.
Low Cost and Efficient Photovoltaic Conversion by Nanocrystalline Solar Cells
Authors: Grätzel Michael 
Published: December 2004

AbstractSolar cells are expected to provide environmentally friendly solutions to the worlds energy supply problem. Learning from the concepts used by green plants we have developed a molecular photovoltaic device whose overall efficiency for AM 1.5 solar light to electricity has already attained 10 %. The system is based on the sensitization of nanocrystalline oxide films by transition metal charge transfer sensitizers. In analogy to photosynthesis, the chemical solar cell achieves the separation of the light absorption and charge carrier transport processes. Extraordinary yields for the conversion of incident photons into electric current are obtained, exceeding 90% for transition metal complexes within the wave‐length range of their absorption band. The use of molten salt electrolytes together with coordination complexes of ruthenium as sensitizers has endowed these cells with a remarkable stability making practical applications feasible. Quite aside from their intrinsic merits as photovoltaic device, the mesoscopic oxide semiconductor films developed in our laboratory offer attractive possibilities for a number Of Other applications. Thus, the first example of a briefly discussed.
Stand der Berechnung bei den Flexibilitäts‐ und Spannungserhöhungsfaktoren von Rohrbögen und deren Auswirkungen auf das Gesamtsystem
Authors: Kauer Robert , Strohmeier Klaus 
Published: December 2004

AbstractIn calculating piping systems components are taken into account by flexibility and stress intensification (SIF) factors. These factors, tabulated in codes, include many simplifications. Considering the component itself this leads to conservative results. Factors can yield wrong data referring to the elasticity of the whole system if the flexibility is computed in this way. Elbows play an enormous role in providing necessary elasticity to accommodate strains caused by temperature or accidental effects. For the elbow the pressureless bend is critical and the stiffness caused by the inside pressure can be ignored. However, this leads to mistakes in the calculation of the piping system elasticity and its reactions with the equipment. For this purpose results from papers are compared with own calculations and a lower limit for the stiffness of pipe elbows is given.
Phasengrenzflächen in Blasenströmungen – Teil 1: Blasensäulen
Authors: Millies Marco , Mewes Dieter 
Published: December 2004

AbstractMehrphasig betriebene Reaktoren, in denen eine Blasenströmung vorliegt, finden eine weite Anwendung in der chemischen und energietechnischen Industrie. Zur Auslegung dieser Reaktoren muß die vorhandene Phasengrenzfläche berechnet werden. Sie läßt sich auf die Größenverteilung der Blasen zurückführen. Die Größenverteilung der Blasen ist lediglich mit sehr hohem Aufwand aus den Bilanzgleichungen von Koaleszenz und Zerfallsvorgängen für jede einzelne Blasenfraktion berechenbar. In der vorliegenden Arbeit werden diese Bilanzgleichungen aufgestellt und mit Hilfe einer analytischen Näherungslösung vereinfacht. Als Ergebnis wird eine einzige Bilanzgleichung für wahlweise das mittlere Blasenvolumen, die Anzahldichte der Blasen oder die spezifische Phasengrenzfläche erhalten. In dem vorliegenden ersten Teil werden lediglich die spezifische Phasengrenzfläche und die Größenverteilung der Blasen in Blasensäulen berechnet, und zwar für niedrige Gasgehalte und reine, niedrigviskose Flüssigkeiten, so daß Großblasen und Gaspfropfen noch nicht berücksichtigt werden müssen.
Phasengrenzflächen in Blasenströmungen – Teil 3: Koaleszenzhemmung
Authors: Millies Marco , Mewes Dieter 
Published: December 2004

AbstractThe first part of this contribution [1] presents the population balances, i.e., balance equations for the numerical density of the bubbles in the individual bubble fractions. They are solved approximately by an analytical approach. There results a straightforward balance equation for the average bubble volume. This equation can be solved analytically for simple fields of flow. For complex fields of flow it has to be solved by a numerical approach. The result obtained is the bubble volume at any time and place averaged from the size distribution of the bubbles. This permits calculation of the local size distribution of the bubbles with the aid of the approximate analytical solution. In the second part of this contribution [2], this balance equation is extended to cover large gas volumes. Large bubbles and gas plugs then occur. These possess a very small interfacial area relative to their volume. They have high rise velocities and thus short residence times in the flow. They therefore participate to only a slight extent in mass and energy transfer and have to be considered, for example, in calculation of the conversion on a chemical reaction or the mode of action of an evaporator. The calculations are performed for pure liquids and compared with the authors' own and other experimental results. The liquids used industrially are generally mixtures of substances. In such liquids the coalescence behavior deviates significantly from that in pure liquids. The influence on coalescence and thus on the interfacial area is examined in the present paper.
Fettpolymere – Herstellverfahren und Eigenschaften
Authors: Behr Arno , Ritter Wolfgang , Zauns‐Huber Rudolf 
Published: December 2004

AbstractThe radical polymerization of esters of acrylic, methacrylic or crotonic acid with fatty alcohols proved to be an efficient method for production of polymers with hydrophobic moieties. By co‐polymerisation with hydrophilic co‐monomers ‐ such as maleic anhydride ‐ copolymers with a broad spectrum of properties can be designed. As an example the copolymerisation of fatty crotonates with maleic anhydride was studied in detail. The reaction was carried out as bulk polymerisation in a semi‐batch process. By this method the compatibility problems of the two monomers, which have very different hydrophilicities could be overcome. The product acts as a very effective fat liquoring agent in leather treatment: the maleic moieties cause an outstanding fixing of the agent on the leather and the fatty crotonate moieties create a very smooth leather. Terpolymers of fatty acrylates, hydrophilic monomers and terpenes could also be synthesized in a similar way. These terpolymers proved to be useful as dispersing agents for pigments in paints and varnishes.
Planungs‐ und Simulationssysteme in der Prozeßindustrie
Authors: Heydecke Jens , Kovriguin Oleg V. 
Published: December 2004

AbstractEfficient scheduling systems are able to enhance production flow and production times in process industry. Scheduling, in this case, means simulation with alternatives of resources and/or activities. The result will be the exact time of output for each activity and the resulting profiles of capacity vectors concerning the recommended resources. In contrast to this, common planning systems add only the user defined production time of activities. Especially for flexible plants with batch production and a variable spectrum of products, as weil as for plants in the stage of design or enlargement, scheduling systems can be very helpful in identifying bottlenecks and over‐capacities. Therefore, reduction of costs in a significant extent and additional benefits can be realized, provided that the individual conditions and objectives have been taken into account.
Glanz und Elend technischer Prognosen
Authors: Renn Ortwin 
Published: December 2004

AbstractPeople depend upon technology, at work and in everyday life. Without organisational and technological intervention in nature humankind would never have been able to maintain the population densities encountered today or uphold an ethical claim to an individual livelihood in dignity. At the same time, however, technology creates new risks. The extent to which the risks arising are balanced by the desired benefits often evades prediction since many consequences of the application of technology are uncertain and are also judged ambivalently by the persons affected. Forecasts can only predict probable or possible developments, but cannot overcome the genuine uncertainty surrounding the future. For this reason assessment of the consequences of technology cannot reveal all negative effects, or even promise the certainty of a positive cost‐benefit balance. Instead, it is the task of assessment of the consequences of technology to initially establish the potential positive and negative consequences according to the best available knowledge and on the basis thereof to harmonize the possibilities of modifications and conditions of introduction with the developers and users of technology. The most suitable approach utilizes discursive procedures in which scientists, manufactures, users, and other affected persons together have to assess the possible consequences.
Einsatz von korrosionsbeständigen Stählen in der chemischen Industrie — Bedeutung, Erfahrungen und zukünftige Anforderungen
Authors: Heinke Günter , Korkhaus Jürgen 
Published: December 2004

AbstractCorrosion resistant steels – especially the austenitic and the ferritic‐austenitic “duplex” grades – represent basic materials of construction for the chemical industry. They serve in cryogenic and high temperature applications, but are most often used in aggressive highly acid to alkaline, frequently aqueous media. The criteria for the selection of corrosion resistant steels are governed not only by the corrosion resistance requirements, but also may be dominated by product cleanline and other process requirements. The development and the market introduction of corrosion resistant steels is closely connected with developments in the chemical process industry. Service experience for corrosion resistant steels is reported, and critical failure mechanisms like pitting and stress corrosion cracking, and their avoidance by appropriate material selection, are mentioned.
Innovative Verfahren mit komprimierten Gasen
Authors: Bungert Bernd , Sadowski Gabriele , Arlt Wolfgang 
Published: December 2004

AbstractBy exploiting thermodynamic phenomena in systems with compressed gases, the properties of products such as their morphology and the size of particles and fibers can be tailored to industrial needs. Separation of complex mixtures can be accomplished. Processes that are conventionally operated in a number of costly steps can be reduced to a few operations. This article gives a phenomenological classification of such processes and explains the underlying principles. Operations developed on a laboratory scale as well as those already established in industry will be discussed.
Anforderungen und Möglichkeiten bei der Verfahrensentwicklung in der Trocknungstechnik Ein Vergleich realisierbarer Vorgehensweisen bei unterschiedlichen experimentellen Möglichkeiten
Authors: Liedy Werner 
Published: December 2004

AbstractFor many products the drying step exerts a great influence on price and application properties. Therefore great effort should be invested in developing and optimizing drying processes. This paper presents a structured procedure for the development of drying processes. In the case of optimal experimental equipment an “ideal” method of proceeding is indicated. Furthermore it is shwon how to develop and optimize drying processes very successfully with little experimental equipment or even if there is no experimental equipment available. Papers published in this field treat only special aspects or presume optimal experimental equipment. This paper is specially interesting for users with limited experimental equipment.
Prozeßmodellierung bei der metallorganischen Gasphasenepitaxie
Authors: Dauelsberg Martin , Durst Franz , Kadinski Lew , Makarov Yuri N. 
Published: December 2004

AbstractThis article provides a brief survey of mathematical modelling of metalorganic vapour phase epitaxy (MOVPE), a step in semiconductor processing of III‐V compound semiconductors serving as basis for the production of electronic and optoelectronic components. The process model for MOVPE is based on the mathematical description of gas flow for a MOVPE reactor coupled with heat transfer and mass transport, including multicomponent diffusion, thermal diffusion, and homogeneous and heterogeneous chemical reactions. Several approaches to the description of multicomponent mass transport, of the modelling of heat transfer in terms of thermal radiation, and of the actual growth process on the growing semiconductor surface are considered. The process modell is applied to MOVPE of GaAs in an industrial multilayer reactor and the calculated results validated with the aid of experimental results.
Experimentelle und numerische Modellierung der Wirkung von Gas‐ und Staubexplosionen
Authors: Schumann Steffen , Rastogi Ashok Kumar , Fucke Wolfgang , Friehmelt Volker 
Published: December 2004

AbstractSince the intensity of an explosion increases substantially on damming or as a result of turbulence‐generating obstacles, gas or dust explosions in industrial plant can cause considrable damage. In connection with various research projects, medium and largescale experimental studies on gas and dust explosions were undertaken in order to gain detailed information about the course and effects of explosions under realistic conditions and to assess possible means of improving safety precautions. Some typical experiments on expansion in dust explosions are presented on the basis of the measured explosive pressures and flame lenghts and compared with the calculated results obtained using the BASSIM CFD code developed by Battelle or by empirical modelling.
Die auf einer Stoffstromanalyse basierende Implementierung von vorsorgendem integrierten Umweltschutz
Authors: Schnitzer Hans 
Published: December 2004

AbstractProperly implemented environmental protection can prove to be an economically sound and profitable approach for processing and manufacturing industry. This requires an integrated approach with a systematic consideration, and consequent reduction, of the formation of waste products and emissions. This paper proposes a system for categorisation of the starting materials of production and for classification of waste and emission flows, and an answering strategy based thereon. Avoid ance and reduction of emissions can be achieved in four ways: increasing efficiency, increasing effectiveness, utilisation of by‐products, and substitution of starting materials. Combination of material‐flow analysis with a complete plant environmental cost calculation helps to clarify the economic benefits of production‐integrated environmental protection. More than 100 case studies conducted within the framework of cleaner production programs in Austria demonstrated the soundness and feasibility of thes approach.
Stoff‐ und Energiewandlungen bei verfahrenstechnischen Prozessen
Authors: Fratzscher Volfgang 
Published: December 2004

AbstractMass and Energy Conversion in Processes of Chemical Engineering. Being the practice of chemical engineering, chemical industry is among the industrial branches with a high energy consumption. This is scientifically based on the unity of mass and energy conversion. Although theoretically well‐known these interconnections have only little influence on engineering investigations. That's why incomplete and untrue evaluations of the energetic conditions of chemical processes can occur. After a brief historical survey, a classification of the different kinds of energy for chemical processes will be proposed as a help in solving this problem. This classification facilitates a deeper understanding of the energetics of chemical processes. To increase these investigations the term cumulative exergy expenses can be used for the evaluation of chemical processes. This evaluation considers both the conversion of energy and the conversion of mass. These connections are discussed by one example. If these research purposes are generalised for strategic development, they will lead to a new generation of chemical and energetical plants.
Betriebsleittechnik – Funktionsumfang und Stand der Systeme
Authors: Kersting Franz‐Josef 
Published: December 2004

AbstractProcess Control Engineering – Function and State of the Art of the Systems On considering material flow in a chemical engineering company it is possible to identify associated business processes whose support by appropriate information processing systems will permit efficient control of material flow and material conversion as production goal. Such consideration indicates not only the principal functions of information processing but also the necessary integration of process‐oriented information systems such as those relating to formulation, production planning, and operating data processing. Various concepts are currently under discussion for such integration.
Prozeßführung
Authors: Schuler Hans 
Published: December 2004

AbstractProcess Management The concept of “process management” is being increasingly used as a complement to similar concepts such as process automation, process control, etc. Such terms are defined within a framework of more general conceptional trends, which can be characterised by terms such as integration and holistic. Considerable potential exists with this framework for fruitful joint development of the main disciplines contributing to process management, viz. process engineering and automation engineering. Such developments remain inaccessible to the individual disciplines. The present article considers this concept from an industrial viewpoint.
Thermodynamische Grundlagen der Reaktivdestillation
Authors: Frey Thomas , Stichlmair Johann 
Published: December 2004

AbstractThermodynamic Fundamentals of Reactive Distillation Reactive distillation means the simultaneous implementation of reaction and distillation in a counter‐current column. The effective phase equilibrium is very complex since the chemical equilibrium is superimposed on the vapor liquid equilibrium. The paper focuses on the calculation and presentation of this equilibrium using so called reactive distillation lines. This leads to a clear explanation for the existence of reactive azeotropes and to a simple method for the determination of the concentration of these azeotropes. The effectiveness of this method is demonstrated on several mixtures with different reaction mechanisms.
Expedition ins Datenreich: Wie kann man Informationen in Produkt‐ und Prozeßdaten umfassend erschließen?
Authors: Estler Manfred , Hilpert Ralf , Soravia Sergio 
Published: December 2004

AbstractExploring the Data World: How Can We Extract the Maximum Information from Product and Process Data? In various areas of the chemical industry a wealth of product and process data of various kinds is generated and recorded. In the majority of cases these data have only been evaluated fragmentarily and not systematically in terms of their information contained. Following the acquisition and possible short term visualization they end up in regular “data graveyards”. Furthermore, these data often stem from different sources such as distributed control systems (DCS), laboratory information and management systems (LIMS), or shift logs. There is a great potential for an improvement of product quality, process control, and plant safety, as well as for a reduction of inspection costs in the compilation and systematic analysis of these data. In addition to classical statistical methods, new data analysis techniques are increasingly used. After a brief explanation of the procedure used in data analysis projects and a presentation of several methods, an example illustrates which results can be obtained from an approach to data analysis that is not yet widespread in the process industry.
Eine Querschnittstechnologie drängt zum Markt: Die Möglichkeiten der modernen Biotechnologie
Authors: Marquardt Rüdiger 
Published: December 2004

AbstractThe Scope of Modern Biotechnology Any attempt to explain the term “modern biotechnology” and to distinguish it from classical biotechnology soon reveals that the boundary is anything but distinct and frequently disappears in a terminological fog. Things only become easy when modern biotechnology can be defined as using the methods and processes of genetic engineering. This is indeed often the case, but not always. Modern biotechnology embraces advances in process engineering as well as new developments in equipment; it depends on monoclonal antibodies and new cell culture techniques, it benefits from advances in embryonal transfer in the animal kingdom and also from cloning; it is taking over large areas of environmental engineering. This list could be continued. Processes of classical biotechnology are always involved in the production of a modern biotechnological product. It is ultimately irrelevant to the engineer whether a fermenter contains genetically engineering microorganisms or not; or to the farmer whether the potatoes he grows are genetically modified or not. There can be no modern biotechnology without classical biotechnology – and the reverse will soon also be true.