bluuebunny/crossref_metadata_2025_split huggingface dataset:
Verschleiß selbsttätiger Pumpenventile durch abrasive Suspensionen
Authors: Vetter Gerhard , Störk Ulrich 
Published: December 2004

AbstractWear of automatic pump valves by abrasive suspensions. In pumping of abrasive suspensions with reciprocating displacement pumps against high pressures, the pump valves prove to be subject to serious wear. Wear of the piston seal can usually be avoided by washing or by separating membranes. Pump valves are fitted with elastic or rigid seals. To resist corrosion and temperature effects, frequently the only possible approach is to finish them in metallic or carbide materials. The major kinds of wear are demonstrated by a tribological study. The rates of wear found for a real valve model with a high pressure experimental setup depend upon the pressure and frequency of reciprocation. A hardness‐dependent region of instability exists where wear scoring arises. The volume wear rate for various arrangements of materials and abrasive particles exhibits a crest/trough nature. A design strategy and construction aspects are considered and compared with practical experience.
Simulation industrieller Verbrennungssysteme
Authors: Görner Klaus , Zinser Walter 
Published: December 2004

AbstractSimulation of industrial combustion systems. This contribution surveys the state of the art of mathematical modelling of industrial flames and combustion chambers with the aid of examples. No claim is made to completeness. It should be noted that the complexity of the mathematical model is limited by available computer power, even though this power is increasing, and one is thus compelled to concentrate on essential aspects in calculating combustion chambers. Nevertheless, valuable results are obtainable here, which often cannot be gained in a real system because the geometric dimensions are too large, or specific quantities cannot be measured, or a firing plant cannot be disturbed in operation. In the area of pollutant production, mathematical models help to provide an understanding of the operating mechanisms and possible means of influencing them. However, the greatest advantage over series of measurements lies in the possibility of performing parametric studies under otherwise identical conditions, which proves very difficult or impossible in practice.
Dia‐ und Ultrafiltration – Stofftrennverfahren in der chemischen Industrie
Authors: Samhaber Wolfgang M. 
Published: December 2004

AbstractDia‐ and ultrafiltration – separation processes in the chemical industry. The use of ultrafiltration membranes for purification and concentration of chemical or biotechnological products has a wide scope of application in industrial practice. Continuing development and improvement of membranes, and especially the increasing availability of favourably priced membranes for these applications, is increasing the use of these separation processes in chemical production. The present contribution deals with theoretical principles, potential applications, and aspects of industrial practice of these separation methods. Above all, the topic is surveyed from an industrial viewpoint.
Hydrodynamische Belastbarkeit von Mikroorganismen
Authors: Märkl Herbert , Bronnenmeier Reinhold , Wittek Bernd 
Published: December 2004

AbstractHydrodynamic stress resistance of microorganisms. The production of microbial metabolites and the growth of microorganisms are affected by mechanical forces, such as occur on stirring, pumping, and aeration in industrial equipment. This paper considers the methods of investigation and typical experimental results. The sensitivity of the organisms depends upon the stability of the cell wall and upon its morphology. Raising the viscosity of nutrient solution increases the symptoms of damage at a given stirrer speed. In the case of methane‐producing microorganisms, growth and product formation (methane production) are affected in the same manner. Physiological stress, induced for example by the absence of essential nutrients, proves additive to mechanical stress in its effect. It is suggested that the power dissipation per unit volume should be taken as a guide on scale‐up or on transfer of experience gained with one kind of flow system (e. g. jet flow) to another (e. g. stirred tank).
Die Schweißverbindung im chemischen Apparatebau und ihr Korrosionsverhalten im Betrieb
Authors: Bäumel Anton 
Published: December 2004

AbstractWelded joints in the construction of chemical equipment and their corrosion behaviour in operation. This contribution surveys the possible kinds of corrosion damage to fully austenitic welded stainless steels in the presence of heat cracks. Such cracks can be avoided by the presence of ß‐ferrite. However, under certain conditions of attack ß‐ferrite can cause selective corrosion. That is especially so on decomposition of ß‐ferrite. Intercrystalline susceptibility in the zone of thermal influence can be avoided by use of stabilized or low‐carbon steels. The tendency to undergo granular disintegration increases with increasing nickel content. The resistance to pitting of stainless steels is reduced at places bearing tempering colour layers. Such layers should therefore be avoided in welding or they should be removed if they persist in formation.
Oberflächen‐ und Dünnschichttechniken in der Industrie
Authors: Menz Wolfgang 
Published: December 2004

AbstractSurface and thin film technology in industry. Modern surface and thin film technology enables us to consider the bulk and surface properties of a material independently of each other. The advantages for industrial production are therefore the potential savings in materials and processing. This paper discusses selection of processes which have already become established in the automotive industry. A major topic in research and development of thin film technology is the change from open loop processes to closed loop processes. For that reason it is necessary to work on improvements to the analytical tools, on the one hand, and on the theoretical modelling of thin film structures on the other.
Elektrochemische Energieumwandlung in Brennstoffzellen
Authors: Wendt Hartmut , Jenseit Wolfgang 
Published: December 2004

AbstractElectrochemical energy conversion in fuel cells. With the exception of high temperature fuel cells, fuel cells burn hydrogen fuel exclusively at low temperature giving energy conversion efficiencies of 40 to 60%. Alkaline cells, phosphoric acid cells, and membrane cells operate at low temperatures, whereas molten carbonate cells and zirconium dioxide membrane cells are designed as high temperature cells. The alcaline fuel cell has so far been used only for special purposes, such as space missions and miltary applications. The phosphoric acid cell is suitable for modular heating plant between 0.5 and 5 MW which are fueled with natural gas. It has demonstrated its technical reliability in a large‐scale field test in the USA and an economical breakthrough is expected in the next few years. The two high temperature cells face a longer development phase, yet hold promise of better econmic performance thanks to their greater efficiency.
Sicherheit im Chemieapparatebau mit Borosilicatglas
Authors: Wedel Walter 
Published: December 2004

AbstractSafety in chemical equipment construction with borosilicate glass. Thanks in particular to its universal corrosion resistance borosilicate glass has acquired a firm place among the materials of construction for pipework, equipment, and plant in chemical engineering. Pertinent technical rules containing all necessary material data and regulations are available for design and planning. Observation of these regulations and adherance to appropriate designs ensure a high degree of safety in operation of glass installations in the rough conditions of a chemical plant.
Reinigung lösungsmittelhaltiger Abluft – alternative Möglichkeiten
Authors: Heck Günter , Müller Günter , Ulrich Michael 
Published: December 2004

AbstractPurification of solvents containing air – Alternative methods. Different processes are used for the purification of solvents containing air: condensation, absorption, adsorption, combustion, membrane permeation, and biofilters or bioscrubbers. The processes will be explained by examples. The specifications required by “TA Luft” often cannot be reached only by condensation and membrane permeation. The success of absorption depends on the scrubbing liquid. Glycol ethers are useful scrubbing liquids – especially for chlorinated hydrocarbons. The choice of the process depends on the volume flow rate, the solvent concentration, and the kind of solvent. Recycling of the solvents reduces the costs of the process.
Hochreines Monosilan für die Elektronikindustrie – Synthese, Reinigung und Charakterisierung
Authors: Klockner Hans‐Jürgen , Eschwey Manfred 
Published: December 2004

AbstractHigh‐purity monosilane for the electronics industry – Synthesis, purification, characterization. Monosilane is used in the electronics industry in the production of integrated circuits and in the manufacture of amorphous silicon devices such as solar cells, photocopier drums, and flat TV screens. The first German production unit for high purity monosilane gas which came on stream in 1987 is presented. The gas produced in a molten salt process is purified to highest quality and analyzed.
Verwertung von Klärschlamm
Authors: Wenning H. Peter 
Published: December 2004

AbstractGasification and pyrolysis of sewage sludges. Gasification and pyrolysis of sewage sludge were examined as alternatives to sewage sludge combustion. For this purpose, experimental gasification and pyrolysis tests were carried out with primary sewage sludge of Emschergenossenschaft. Main objective of these tests was the evaluation of yields and qualitites for products gained via sludge gasification or pyrolysis and an assessment of the environmentally relevant properties of the related residues. Both process alternatives enable the utilization of sewage sludge without any negative impact on the environment. Due to the total use of the organic components out of the sewage sludge in combination with an almost complete utilization resulting from the valuable hydrogen produced, gasification is an attractive alternative compared to the burning of sewage sludge, both from an environmental and an economic point of view. In the case of sewage sludge pyrolysis a portion of the organic components, however, will remain in the pyrolysis residue. Therefore, pyrolysis allows only a minor reduction of the residual product.
Wellenausbreitung in verfahrenstechnischen Prozessen
Authors: Marquardt Wolfgang 
Published: December 2004

AbstractWave propagation phenomena in chemical engineering processes. A phenomenological analysis of the dynamics of a number of different distributed parameter systems in chemical engineering reveals a surprisingly simple dynamic behaviour despite the complexity of the underlying nonlinear process models. Spatial structures or waves are propagating along a spatial coordinate during transients. The dynamics of most of the processes under consideration can be described with sufficient accuracy by three different model structures. These models serve as a basis for a theoretical system analysis. The investigation of characteristic properties of the propagating waves and the mechanisms responsible for wave formation are of central significance. Finally, it is shown how the extended knowledge about the processes may be applied for the solution of problems of technical interest.
Vergleich von Verfahrenskonzepten zur Rauchgasreinigung bei der Rückstandsverbrennung
Authors: Denzer Wolfgang , Faulhaber Friedrich Richard , Herrmann Eberhard 
Published: December 2004

AbstractComparison of process concepts for flue‐gas clean‐up in residue incineration. Depending on the residues being dealt with, industrial residue incinerators may produce flue gases having widely varying separation properties. This applies especially to particulate constituents. To determine unknown separation properties, to select suitable separation methods, and to predict the separating behaviour of the envisaged equipment, use can be made of pilot plants or very small test plants. Experiments have been carried out on two residue incinerators of different size using rotary‐kiln technology in order to ascertain the suitability of various processes for separating particles from flue gases. For wet treatment a venturi scrubber and a scrubbing column were investigated, and for dry treatment the methods of electrostatic precipitation and cloth filtration. Various alternatives for dust separation have been derived from, and assessed on the basis of, the experimental results. Discussion of the experimental results shows that reliable prediction of the operating behaviour of industrial‐scale units will require further basic investigations regarding dust separation and gas scrubbing. The task of enabling cleaned‐gas values to be reliably predicted is beyond the development potential of individual manufacturers, individual operators, and individual university institutes. What is essential is the development of a joint concept under which the various tasks will be distributed and coordinated.
Strahlungsaustauschrechnungen mit der Monte‐Carlo‐Methode. Theorie und Anwendungen auf technische Verbrennungssysteme
Authors: Görner Klaus , Dietz Uwe 
Published: December 2004

AbstractRadiation exchange calculations by the Monte Carlo method. Theory and applications to industrial combustion systems. The goal of this contribution is to indicate possible applications of the Monte Carlo method to calculation of radiation exchange process in combustion plant. A brief introduction to the method is accompanied by an account of modelling of radiation exchange and a description of the optical properties of the combustion chamber suspension. The Monte Carlo model used is presented and special formulations are given. The application of the method for the calculation of technical combustion systems is illustrated for two large‐scale combustion plant (coal‐ and lignite‐fired). Flow and thermal yield are estimated in order to reduce the computational effort and to achieve industrially relevant applicability. The simulated results show good agreement with available measurements. Coupling with complete flame and combustion chamber models in which turbulent binary flow and local heat liberation are calculated is feasible and is discussed in the final section.
Die Anwendung von Expertensystemen zur Katalysator‐Entwicklung
Authors: Körting Erich , Baerns Manfred 
Published: December 2004

AbstractUse of expert systems in catalyst development. Present‐day catalyst development is still based largely on empirical knowledge; in very few cases is it possible to design a catalyst solely on the basis of theoretical concepts. Expert systems, which make empirical knowledge available together with theory and in appropriate combinations should be utilizable for catalyst development. The article describes the present state of the art and indicates possible applications with the aid of an already developed prototype. The system suggests catalytically active components for hydrogenation of carbon monoxide to (1) methane, (2) C2+ hydrocarbons, as well as (3) methanol and (4) C2+ oxo products, and makes suggestions for choice of reaction conditions.
Trends beim Einsatz von Realzeitrechnern für Forschung und Entwicklung in der Technischen Chemie
Authors: Lübbert Andreas 
Published: December 2004

AbstractTrends in the use of real‐time computers for research and development in industrial chemistry. Computers are integral parts of the complex equipment of chemical production plants. They are tools for computer aided process control. In production plants as well as in research and development laboratories, dedicated computer systems are used more and more. E. g., nearly all measuring devices will be controlled by their own microprocessors in the near future. In chemical engineering, however, the most significant developments are taking place in the software domain. The main trend in applications‐software developments is the enhanced importance of the support of the plant operators by means of improved user interfaces. Within the research and development field, the software must be more flexibly adaptable to changes in the process equipment and due to changing control algorithms than in production plants. Moreover, efforts are being made to improve control by exploiting as much as possible a priori knowledge on the system in question. A current development in this direction, which will become stronger with time, is known under the heading „expert systems”︁, in which heuristic know‐how of operators is made available and usable in process computers to improve control.
Auslegungskriterien für elektrostatische Emulsionsspaltanlagen
Authors: Draxler Josef , Marr Rolf 
Published: December 2004

AbstractDesign criteria for electrostatic de‐emulsifiers. Electrostatic de‐emulsifiers have been successfully used over many years for desalting of crude oil. The emulsions used for this application are rather unstable and break down easily. Different equipment and conditions are required for highly stable emulsions, such as are used for liquid membrane permeation. To permit use of higher field strengths without danger of short circuiting this new equipment must be fitted with insulated electrodes, with preference being given to glass‐insulated liquid electrodes. An important feature is also a defined distance between the electrodes which are arranged in concentric manner to increase the de‐emulsification rate. The rate of de‐emulsification can also be increased by using high frequency (10 kHz) instead of the usual low frequency (50 Hz) alternating voltage.
Ausbildung von Verfahrens‐Ingenieuren und Vergleich von Abschlüssen innerhalb der EG
Authors: Stephan Karl 
Published: December 2004

AbstractEducation of chemical engineers and comparison of qualifications within the European Community. The present survey compares and contrasts the various structures of engineering education, and especially of chemical engineering education, in the member countries of the European Community (EC). Each of the different education systems within the EC has its advantages and disadvantages and none of the systems is definitely superior to others. Each system is largely the product of national pecularities and should be seen in the light of the specific cultural background. This often impedes a complete transfer of single elements from one system to another. Proven principles of other education system should, however, serve much more than has been the case in past as a guideline for reforms in our country. Possible steps in this direction are discussed.
Herstellung und Anwendungsmöglichkeiten von Cyclododecatrien und Cyclooctadien
Authors: Streck Roland , Hartig Herbert 
Published: December 2004

AbstractProduction and applications of cyclododecatriene and cyclooctadiene. Today the cyclic trimerization of 1,3‐butadiene to cyclododecatriene and the synthesis of cyclododecatriene derivatives are accomplished on an industrial scale using fully developed processes. This paper surveys the variety of the derivatives and their applications. The cyclic dimerization of 1,3‐butadiene to cyclooctadiene and the synthesis of cyclooctadiene derivatives have also been performed on a technical scale for some years now. The paper gives examples of these derivatives, including polyoctenamer a rubber whose properties are considered to be due to the presence of cyclic macromolecules.
Exergetische Analyse und Bewertung verfahrenstechnischer Prozesse mit einem Flow‐Sheeting‐Programm
Authors: Munsch Martin , Mohr Thomas , Futterer Eberhard 
Published: December 2004

AbstractExergy analysis and assessment of process plants with flow‐sheeting systems. Mass and enthalpy balances are necessary for the calculation and assessment of process plants. The economic and ecological results cannot be optimal because the different value of energy according to the Second Law of Thermodynamics and the influence of the environment are not included. This is accomplished by exergetic analysis and assessment. The aim is to obtain an exergy analysis and assessment of any process plant through combination with a flowsheeting system. Because the exergy is dependent on the choice of a reference state, an environmental model is proposed which is suitable in regard to the above‐mentioned aim.
Neue Erkenntnisse zum Mischverhalten von Submersreaktoren
Authors: Lübbert Andreas 
Published: December 2004

AbstractMixing behaviour of submersed reactors. New improved measuring techniques lead to new insights into the local mixing behaviour of submerse reactors. As exemplified by airlift tower loop reactors, it is shown that it is possible to obtain more information from gas residence time distributions if the signal‐to‐noise ratio of the measurement can be improved significantly. Additional information is obtained, e.g., on that part of the gas recirculated around the loop or the circulation time of the gas phase. The recirculated gas significantly influences the gas backmixing in such reactors. A more thorough investigation of the gas phase motion requires locally resolved data. For the properties of the gas phase, local measuring techniques are available, which allow for measurements of the mean bubble velocity profile even during production runs in large aerated stirred tank reactors. The results show that the gas backmixing is acutely dependent on the viscosity of the continuous liquid phase. Complementary measurements on the properties of the continuous liquid phase can be investigated by means of the heat‐pulse‐technique. This also is applicable in real media, e.g., during biotechnological cultivation runs. Besides the measurement of the mean liquid velocity, one can, furthermore, obtain some information on the locally dominating mixing mechanism. One significant result of such investigations is that in the airlift reactors investigated the bubble‐wake mixing mechanism dominates, whereas the isotropic turbulence in terms of the statistical turbulence theory plays a secondary role. This even holds at very high energy inputs.
Rechnergestützte exergetische Optimierung verfahrenstechnischer Prozesse
Authors: Futterer Eberhard , Gruhn Günther , Munsch Martin , Mohr Thomas 
Published: December 2004

AbstractComputer‐aided exergy optimization of chemical engineering processes. Methods of exergy evaluation as the basis of energy and material analysis of chemical processes have been used for some years to evaluate these processes from the view point of the First and Second Law of Thermodynamics and with regard to their influence on the environment. This paper introduces a tool for computer‐aided exergy analysis and optimization of complex process plants. This tool is based on a flowsheeting program that is extended to calculate the exergy of material, heat, and work flows. The optimization problem of process plants is solved in a two level approach by parameter optimization and structural optimization. The parameter optimization is realized automatically by the extended flowsheeting program. The structural optimization is based on heuristic rules and experiences of the process engineer.