bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Auslegung von Kühlerkondensatoren zur partiellen Kondensation von Dämpfen aus strömenden Gas/Dampf‐Gemischen
Authors: Rennhack Rolf , Numrich Reiner 
Published: December 2004

AbstractDimensioning of cooler condensers for partial condensation of vapours from gas‐vapour mixtures. This contribution surveys present knowledge in the field of partial condensation with related hints about dimensioning cooler condensers. In case of an atmospheric and slightly increased pressure and moderate shearing forces of the gas‐vapour mixture on the condensate film being formed, the film theory is sufficient. However, it is necessary to include the Stefan correction for unilateral diffusion. High sharing forces lead to entrainment. The results of the few experimental publications show that the film theory is no longer valid immediately before entrainment is reached. Nor can it be used in the area of high pressure. There are not enough experimentally and theoretically proved correlations for dimensioning so that it is necessary to use empirically found average overall heattransfer coefficients. The use of well‐known correlations to determine limits of entrainment makes it possible to prove whether the film theory is valid or not in every single case.
Fortschritte bei der Abscheidung von Stäuben im Elektrofilter unter Berücksichtigung der Schadgas‐Adsorption
Authors: Mayer‐Schwinning Gernot 
Published: December 2004

AbstractProgress in dust collection by electrostatic precipitators with due attention to adsorption of noxious gases. It is shown on the basis of the present state of the art that the stipulations of the pollution control legislation for large boilers can be met by electrostatic precipitators and that fine dust and heavy metals are collected to a sufficiently high degree. Recent developments are dealt with which bring about a fundamental improvement of the collection in the precipitator. Noxious gases have to be separated together with the dust to an ever‐increasing extent. With dry processes, fluidized beds are arranged upstream of the electrostatic precipitator for the adsorption of, for instance, HCl, HF, and SO2. In these cases the dusts will be highly concentrated and of varying chemical composition. Dry gas cleaning in the expanded, circulating fluidized bed downstream of refuse incineration plants and defluorination of waste gases from aluminium electrolysis are considered as examples. The separation of dust under difficult conditions is then dealt with.
Schadensuntersuchung an organischen Werkstoffen im Chemie‐Apparatebau
Authors: Schindler Helmut , Gräfen Hubert 
Published: December 2004

AbstractInvestigation of damage to organic materials in chemical apparatus engineering. There are many different possible causes for the failure of structural elements or of linings and coatings made of organic materials under such load conditions as those found in chemical plant. Despite the general suitability of the engineering plastics used, design and manufacturing defects are often the cause of premature failure. Installation faults are also found on occasion. Other sources of damage include the chemical and physical effects of media on organic materials. These are due in part to the unsuitability of the material used, the effect of corrosive components in the media involved often being either not recognized or underestimated; on the other hand, the damage may also be caused by inherent stresses in the structural elements in conjunction with the physical or chemical effects of the media, resulting in stress cracking or stress corrosion cracking. Damage cases of this type are described on the basis of numerous examples, the causes ascertained through intensive investigation of the damage and suitable remedies described.
Lösungsmittel‐Auswahl bei der Flüssig/Flüssig‐Extraktion unter physikalisch‐chemischen Aspekten
Authors: Hampe Manfred J. 
Published: December 2004

AbstractSelection of solvents in liquid‐liquid extraction according to physico‐chemical aspects. Selection of appropriate solvents for liquid‐liquid extraction is frequently necessary in process design. High selectivity and capacity are important, but not the only considerations in choosing suitable solvents. In comparing the various solvents, their selectivity and capacity should be examined at infinite dilution of the solute in the solvent. The required limiting activity coefficients may be estimated if no experimental data are available. A preselection of solvents may be accomplished by considering the interactions of the molecules. There are certain parameters quantifying the ability of the components to interact. Therefore, a selection based merely on dielectric constants or solubility parameters is hardly conclusive.
Reaktionstechnische Aspekte der katalytischen Abgasreinigung bei Kraftfahrzeugen
Authors: Löwe Arno , Hoffmann Ulrich 
Published: December 2004

AbstractKinetic aspects of the catalytic detoxification of automobile exhaust. The technology of catalytic converters designed to reduce automobile exhaust emissions has developed considerably in recent years, as is well documented in the available literature. This review is intended to show how the methodology and philosophy of chemical reaction engineering have contributed to this development. A brief survey of possible reactions and actual catalysts is followed by a detailed account of the relevant basic principles of micro‐ and macrokinetics. Preliminary calculations of conversion of noxious substances in monolithic converters may be based upon the assumption that diffusion from the laminarly flowing gas phase to the catalytically active wall coating is the rate‐determining step in a warmed‐up converter. During the critical warm‐up period, after a cold start, the chemical reaction steps offer the main resistance. The points discussed are the extent to which rate equations and kinetic parameters will be influenced by high degrees of dispersion of the noble metals, by catalyst deactivation, or by transient operation conditions. The structure of the highly porous catalyst support as well as metal impregnation profiles can be optimized so that poisoning is strongly retarded by in‐pore diffusion, while the main reactions are affected as little as possible.
Expertensysteme für die Verfahrenstechnik
Authors: Lieberam Armin 
Published: December 2004

AbstractExpert systems in chemical and process engineering. A survey is given of expert systems in chemical and process engineering and adjacent fields of knowledge. The article assumes a knowledge of the basic concepts of artificial intelligence and expert‐system technology. The expert systems, arranged according to their function and domain of expertise, are described and discussed with emphasis on information of interest to the potential user, e.g. on applications, construction, and implementation. Finally, an attempt is made to give an outlook on future applications of technical expert systems and on the abilities which these systems are expected to possess.
Zukünftige Chancen einer elektrochemischen Kohlenutzung
Authors: Kochanek Wolfgang , Kreysa Gerhard 
Published: December 2004

AbstractFuture scope of electrochemical coal utilization. Based on fundamental thermodynamic considerations and with due regard to known electrochemical reactions of coal‐like substances, the potential of electrochemical coal conversion processes is discussed for the following three main groups of primary products: syngas, aliphatic compounds, and aromatic compounds. Thermal efficiencies and yields are compared with those of competing processes. The indirect electrochemical degradation of coal to soluble aromatic compounds with peroxodisulfate as redox mediator is a promising route of potential interest.
Kinetik der aeroben Abwasserreinigung durch Abbau von organischen Verbindungen und durch Nitrifikation
Authors: Wiesmann Udo 
Published: December 2004

AbstractKinetics of aerobic waste water treatment by degrading organic compounds and by nitrification. Both aerobic degradation of organic substances and nitrification can be described by the double substrate kinetics of Monod; dissolved organic material and ammonium or nitrite are the first substrate and oxygen the second one. The determination of the different kinetic coefficients by evaluation of measurements on a laboratory scale is explained first, and known results are then presented and discussed. Finally, it is demonstrated by two examples, viz. the simultaneous oxidation of carbon and nitrogen compounds and oxygen‐limited substrate removal, how reaction kinetic models can be used to obtain important information about the characteristics of the bioreactions.
Formselektive Katalyse in Zeolithen
Authors: Weitkamp Jens , Ernst Stefan , Dauns Harald , Gallei Ewald 
Published: December 2004

AbstractShape selective catalysis in zeolites. In recent years, shape selective catalysis has become an important field of heterogeneous catalysis. Shape selectivity can arise if the pore width of the catalyst resembles the dimensions of molecules or transition states involved in the catalytic reaction. Up till now, zeolites are employed almost exclusively as shape selective catalysts. Examples of the different kinds of shape selectivity are given. The classification of Weisz and Csicsery is presented. More recent concepts are discussed. Measures for a control of shape selectivity are outlined. For a routine characterization of shape selective catalysts, certain test reactions are shown to be useful tools; the two most important examples are the determination of the constraint index and the hydroconversion of long chain n‐alkanes.
Reaktorstabilität und sichere Reaktionsführung
Authors: Eigenberger Gerhart , Schuler Hans 
Published: December 2004

AbstractReactor stability and safe reaction engineering. Stable operating behaviour of chemical reactors and stability in the sense of stability theory of chemical processes are by no means synonymous concepts. Thus, appropriate control can permit reliable operation at a unstable operating point, while even global stability will not necessarily rule out a runaway reaction. The latter is the case when strongly exothermal reactions are characterized by a pronounced parametric sensitivity. In order to delineate the concepts, „stability”︁ and „parametric sensitivity”︁ are explained first for stirred tank and tubular reactors with strongly exothermal reaction. Both the conventional view of reaction engineering and the theory of heat explosion commonly used in reaction engineering are considered in detail. Practical problems of safe reaction engineering are subsequently discussed for the control of batch reactors, the control of semibatch reactors, and the behaviour of bundled‐tube reactors.
Zerstörungsfreie Prüfungen bei Betrieb und Instandhaltung von Chemieanlagen
Authors: Gräfen Hubert , Steiger Klaus 
Published: December 2004

AbstractNon‐destructive testing in operation and maintenance of chemical plant. Non‐destructive tests performed in chemical plant while it is in operation or standing idle are intended to give the plant operator the information on the state of the plant that is needed to ensure safety and availability. The scope of such tests and how often they are carried out depend on the condition of the plant and on the weaknesses that have been found in the course of time. The following are described as special examples of the versatile use of non‐destructive test methods: (a) thermographic and ultrasonic checking of the condition of a rotary furnace; (b) observation of spherical ammonia containers to ensure early recognition of cracking; (c) detection of leaks in high pressure plant items having corrosion resistant linings; (d) metallography of structural element subjected to heavy loads for long periods at elevated temperatures; (e) wall thickness measurement of heat exchanger tubes; (f) on‐site gamma radiation analysis of metallic materials with an portable RFA device.
Verschmutzung in Kondensatoren und Kühltürmen
Authors: Paikert Paul 
Published: December 2004

AbstractContamination in condensers and cooling towers. Considerable changes in thermal performance or the condensation temperature of water‐cooled condensers must always be expected on contamination of the heat exchange surfaces of equipment with high thermal loading. This is practically always the case with water‐cooled condensers of large‐scale steam turbines, whereas air‐cooled condensers on the coolant side work at only low heat flow densities and therefore react much less sensitively to contamination. This article describes relations between contamination and loss of performance in various systems, and commercially available means of prevention and cleaning are indicated. This state of the art description includes measures for cleaning wet and dry cooling towers.
Herstellung und Instandhaltung verfahrens‐technischer Einrichtungen aus der Sicht des Betreibers
Authors: Hedden Horst 
Published: December 2004

AbstractProduction and maintenance of chemical engineering equipment from the viewpoint of the operator. Maintenance of chemical engineering plant is cost intensive, owing to the large size of such installations. A large variety of heavily taxed units in long term use necessitates constant maintenance. All possible means of cost reduction must therefore be exploited. Collaboration between manufacturer and maintainer is one possible area for such measures. All joint efforts must be directed to the faultless unit. Such efforts are nearly always possible without affecting the manufacturing costs of the unit. Various forms of collaboration are conceivable.
Aufgabenstellung und Konzeptfindung bei einer thermischen Abluftreinigung
Authors: Hüning Werner 
Published: December 2004

AbstractTask definition and concept development for a thermal waste air purification system. The present report demonstrates how the properties of waste air and the boundary conditions of the task lead to direct, compelling consequences for the concept, the realization, and the operation of a thermal waste air purification unit. The design of the individual functional groups is always a result of the job criteria and possible influences of other functional groups. The better the adaptation of the plant concept to the demands of the task, the more smoothly the finished plant will run. Very high availability and reliable waste gas quality represent the principal environmentally relevant objectives of such thermal waste gas purification plant. Thermal waste gas/exhaust air purification is presently the most universal procedure for optimum, environmentally appropriate purification.
Experimentelle Identifikation und rechnergestützter Regler‐Entwurf bei technischen Prozessen
Authors: Hensel Hartmut , Isermann Rolf , Schmidt‐Mende Peter 
Published: December 2004

AbstractExperimental identification and computer‐aided control design in technical processes. The transient behaviour of complex processes, such as frequently occur in process engineering, is often known only inadequately, since theoretical (physical) model formation is extremely difficult owing to insufficient knowledge of internal processes. If satisfactory quality of control is to be achieved, then a viable approach is experimental model construction (identification) on the basis of a mathematical process model. Modern computer‐aided identification procedures and computer‐aided control design procedures based thereon or self‐adjusting controls give particularly good results. Furthermore, the design time required is greatly reduced, meaning that computer use can also contribute to considerable saving of costs.
CAD in der Anlagentechnik – Gegenwärtiger Stand, Probleme und Chancen
Authors: Futterer Eberhard 
Published: December 2004

AbstractCAD and plant engineering. State of the art, problems, and prospects. CAD was first used for special tasks, that is for especially sensitive design, e. g. in the aircraft industry, or mass‐produced articles, e. g. in the automotive industry. For about one decade, CAD has been used economically in all areas of design. This paper describes the state of the art of CAD use for plant engineering. It may be seen as the termination of a thorough test. Now the time has come to decide on the future use of CAD. Problems encountered are therefore reported. The prospects of CAD are outlined on this basis.
Thermisches Spritzen im Chemieapparate‐ und Maschinenbau – Anlagen, Werkstoffe, Anwendungen
Authors: Kreisel Klaus , Protogerakis Emmanuil 
Published: December 2004

AbstractThermal spray technique in chemical equipment and machine construction – Plant, materials, applications. The metal spray technique originally used only for repair applications is nowadays also used for production of new equipment since the attainable life expectancy of the coated parts plus the possibility of using inexpensive basic materials result in a significant increase in economy. The use of thermal spray coats in the manufacture of chemical plant calls not only for high adhesion and freedom from pores and cracks but also for good corrosion resistance. The high technological level which has been reached in spray processes as well as the development of suitable spray materials have meant that a satisfactory solution has now been found to a large number of the problems that were still outstanding a few years ago.
Verwendung von Kohlenstoff‐Fasern im Apparatebau
Authors: Böder Horst , von Gellhorn Edgar , Künzel Jürgen 
Published: December 2004

AbstractUse of carbon fibres in equipment constuction. Carbon fibres are characterized by high tensile strengths, high modulus of elasticity, and good corrosion resistance. They are therefore especially suitable for reinforcement of components made of plastics (CFC). Carbon fibre reinforced parts made of resin‐impregnated graphite withstand higher mechanical stress and offer greater reliability in operation. CFP materials is an economical alternative to high‐alloyed steel for use in corrosive media. Apart from graphite CFC is one of the few materials of construction suitable for use up to temperatures of over 2000 °C. It has also been sucessfully used for highly corrosion‐resistant equipment such as grids and piping.
Stand der Technik der Oberflächenveredelung durch Laser
Authors: Mordike Barry Leslie 
Published: December 2004

AbstractState of the art of surface treatment by lasers. Lasers have a great future in surface treatment. Laser surface treatment should not be regarded as a replacement for existing methods. It cannot compete with mass production methods, but can be used whenever a local need arises for special properties or when conventional methods fail. Some new developments, such as laser gas treatment, are also extremely promising.
Fortschritte auf dem Gebiet der Alkalichlorid‐Elektrolyse
Authors: Bergner Dieter , Hartmann Manfred , Staab Rudolf 
Published: December 2004

AbstractProgress in the field of alkali chloride electrolysis. In the field of alkali chloride electrolysis, new developments are restricted almost solely to the membrane cell process, and no longer concern the conventional mercury and diaphragm processes. At present, the membrane process has a roughly 10% share of the world's caustic soda production capacity of about 48 million t NaOH/a. This share includes membrane cells and retrofit diaphragm cells. After dealing with electrolytes and electrolysis products, this review then turns to a discussion of the optimum current density, of cell voltages, current efficiency, and energy consumption. Subsequently, economic aspects are considered in relation to energy and capital expenditure costs as well as to plant construction. Finally, the most recent developments are discussed, especially in the field of oxygen consuming cathodes in membrane cells.
Modelle für die Berechnung der Leckraten aus druckführenden Apparaten und Rohrleitungen in Chemieanlagen
Authors: Friedel Lutz , Westphal Frank 
Published: December 2004

AbstractModels for the calculation of leakage rates from pressure equipment and pipes in chemical plant. A survey of the possible sizes and sites of leaks and of the calculation models hitherto described in the literature shows that the leaks to be expected can only be small slit shaped cracks in the walls of vessels and pipes. Depending upon the location of the leak, gas/vapour or liquid flow, or even two‐phase flow is to be expected from the leak. Only very few semiempirical models are available for calculating two‐phase mass flow density through slits with very small dimensions, such as slit widths of about 0.1 mm; moreover, such models contain only empirical factors which were adjusted to experiments with initially supercooled water. Experience tells us that such relationships cannot be straightforwardly and reliably applied to the exiting of substance systems typical of chemical plant.
Gaswaschanlagen für saure und basische Abgase unter Berücksichtigung der neuen TA‐Luft
Authors: Schaber Karlheinz 
Published: December 2004

AbstractGas scrubbing plants for acid and caustic exhaust gases with consideration of the new TA‐Luft. When designing gas scrubbing plants for acid and caustic exhaust gases from manufacturing plants of the chemical and pharmaceutical industry it is important to pay special attention to the aerosol formation which occurs in the exhaust gas systems and absorbers if the emission values should remain under the determined limit values stated in the Technical Instructions for air‐pollution control (TA‐Luft). The present study explains under what conditions aerosols can occur, how its formation can be prevented, and which gas scrubbers are appropriate for a combined gas‐/aerosol separation. A comparison between two exhaust air scrubbing plants of several stages shows that a gas scrubbing plant for an exhaust air pick‐up system with separation of the acid and caustic components as well as with source exhaust air pick‐up of the highly charged gas flows is considerably more favourable with respect to price than the alternative scrubbing plant for an integrated exhaust air system in which large quantities of fine salt aerosols occur and have to be separated with high energy consumption.
Entwicklung des Pauling‐Verfahrens zur Regeneration von Abfallschwefelsäure
Authors: Plessen Helmold Von , Schalles Horst 
Published: December 2004

AbstractDevelopment of the Pauling process for regeneration of spent sulphuric acid. The Pauling rectification process has proved a successful method of regenerating spent sulphuric acid. The further development of the process in the last ten years has included the production of cast iron materials with improved corrosion resistance for use in the boiling vessels. Other development work concerns the operation of the stirrers and the apparatus, the construction of stripping columns, and the introduction of new types of cooling equipment for the hot concentrated sulphuric acid. Furthermore, the scrubbing of the exhaust gases leaving the Pauling apparatus must be adapted to more stringent demands, also with regard to the increasingly varied composition of the spent acids.
Zeitlicher Druckverlauf bei Explosionen als Grundlage zur Auslegung von Behältern und Apparaten
Authors: Gruber Udo , Puppich Peter , Noll Ewald , Mewes Dieter 
Published: December 2004

AbstractTime‐dependent behaviour of pressure in cases of explosions: A basis for design of pressure vessels and apparatus. The knowledge of the maximum explosion pressure is important for design of pressure vessels subject to danger of explosion. Especially for non‐spherical geometries or plant‐internal pressure relief, the maximum explosion pressure has to be calculated from the time‐dependent pressure caused by a chemical reaction in the vessel. Therefore, a set of ordinary differential equations was solved numerically by means of the method of differences. Examples are drawn from known experimental studies. Turbulence effects are also considered. As a result, an analytical relationship is derived which gives the necessary pressure relief area. Finally the results are compared with those of available formulas. Deviations are explained in detail.