bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strahlendiagnostik — in der Medizin ja, für die Verfahrenstechnik nein? Ein kritischer Vergleich
Authors: Vogg Hubert 
Published: December 2004

AbstractRadiodiagnostics – yes in medical applications, no in process engineering? A critical comparison. There is no doubt that to date medicine has profited most from the application of radiation. There are indeed applications in engineering, including in process engineering, but if one compares the vast field of medical radiodiagnostics, including the important area of computer tomography, to the transmission measurements relying on the same fundamental principles of measurement and employed in engineering, e.g. in the determination of the density of a material, enormous differences can be found as regards both the quantity and the quality of such measurements. This becomes even more apparent if one compares the localization and functional examinations in nuclear medicine to the functional tests performed on process equipment or processes with the help of radiotracers. Whilst today diagnosis with radionuclides is quite commonplace in any major hospital, radiotracer techniques are used but rarely, if at all, in apparatus and process engineering.
Kinetik der Kohlen‐Pyrolyse als Grundlage für die Auslegung technischer Reaktoren
Authors: Van Heek Karl Heinrich 
Published: December 2004

AbstractKinetics of coal pyrolysis as a foundation for the design of technical reactors. The pyrolysis of coal is understood to mean its thermal decomposition at temperatures above 300°C, affording tar and char. It is the basic process underlying coking and the starting reaction of combustion, gasification, and hydrogenation. In addition, pyrolysis offers a means of converting coal into gases and liquids in a „third way”︁ besides gasification and hydrogenation. In order to establish a basis for the design of relevant technical reactors, the kinetics of coal pyrolysis has been investigated as a function of temperature and rate of heating and recently of pressure under inert gases and hydrogen. In particular, the rates of formation and the yields of liquid and gaseous products and the alteration of the solid matter have been examined under pressures ranging from 1 to 100 bar and at rates of heating between 0.05 and 1 000 K/s. It is shown how product formation can be controlled by these parameters and how the experimental data can be applied to reactor design.
Das Auswaschen von Filterkuchen
Authors: Bender Wolfgang 
Published: December 2004

AbstractWashing of filter cakes. The demands placed on the purity of filter cakes exert a pronounced influence on investment and operating costs. Hence a careful study of the washing process is called for. On washing with a medium flowing through the cake it is possible to distinguish three regimes, viz. displacement, intermediate, and diffusional. The amount of washing liquid can be reduced by countercurrent operation, in several steps with repeated stirring of the cake in cases of extreme purity requirements. The washing results in an industrial plant are generally poorer than in the laboratory. The reasons for this discrepancy are more pronounced irregularities in the cake structure, cracking, or an inappropriate distribution of washing liquid.
Einsatz tomographischer Meßverfahren für verfahrenstechnische Untersuchungen
Authors: Mewes Dieter , Ostendorf Wilfried 
Published: December 2004

AbstractUse of tomographic measuring techniques for process engineering studies. Tomographic measuring techniques have so far been employed almost exclusively in medicine and for testing of materials. They permit determination of experimental values for all local coordinates of a given volume at a given time. Classical tomography can be used for measurements only in stationary fields of flow, temperature, and concentration since the object has to be irradiated from as many directions as possible during a finite time interval. In the case of transient events, however, it is necessary to acquire all these values at the same point in time. If transparent fluids are present then coherent light is suitable for irradiation and holographic interferometry for recording the measured values. Since irradiation must take place simultaneously from several directions, the number of recording angles should be kept to a minimum. It is also necessary to employ mathematical procedures for image reconstruction in order to ensure adequate accuracy of the measured values.
Thermisches Hydrocracken von Kohlenwasserstoffen
Authors: Hedden Kurt , Weitkamp Jens 
Published: December 2004

AbstractThermal hydrocracking of hydrocarbons. Thermal hydrocracking or hydropyrolysis processes are currently under development in various modifications for upgrading of heavy oils. The present investigation examines thermal hydrocracking of pure model hydrocarbons. Typical petroleum hydrocarbons, i.e., alkanes, naphthenes, and aromatics were employed. At elevated conversions, alkanes and naphthenes are transformed predominantly into C1‐through C3‐alkanes. Ethane is the main product. In alkylaromatics the side chain is cracked exclusively up to high conversions. Therefore, dealkylated aromatics can be obtained in high yields as intermediate products.
Reaktionstechnische Grundlagen zur Auslegung und zum Betrieb von Bioreaktoren, Teil 1
Authors: Schügerl Karl 
Published: December 2004

AbstractReaction engineering fundamentals relating to design and operation of bioreactors. This review considers the reaction engineering foundations needed for the design and operation of bioreactors: mass and energy balances, thermodynamic data, reaction kinetics, reaction kinetic modelling, reactor models, and the combination of reaction kinetic models and reactor models.
Fortschritte in den wissenschaftlichen Grundlagen zur Auslegung von Kontakttrocknern für grob‐ und feinkörniges, rieselfähiges Trocknungsgut
Authors: Schlünder Ernst‐Ulrich 
Published: December 2004

AbstractAdvances in scientific fundamentals relating to the design of contact dryers for coarse‐ and fine‐grained flowable feeds. Curves depicting the course of drying which used in the design of contact dryers for flowable feeds can be calculated completely, except for a so‐called mixing quality factor, with the aid of known physical characteristics. Drying curves for individual grains are not necessary. The quality of mixing factor depends upon the kind of dryer, the flow properties of the product, and the intensity of the mixing motion. Its numerical value lies between about 2 and 25.
Biologische Abluftreinigung
Authors: Brauer Heinz 
Published: December 2004

AbstractBiological purification of exhaust gases. The biological purification of exhaust typically employs microorganisms to transform undesired components, particularly those with pronounced odours into innocuous products. Since the activity of these organisms is localized in water, the odiferous substances must be transferred from the air to water. Oxygen must also be supplied to the water for product transformation. Large scale plant for biological purification of waste air from agricultural and industrial operations were introduced in Europe in the early 1960's. Since then this new technology has undergone remarkable developments. The principal plant types are biofilters, dripping units, and bioscrubbing units. In compost production and agriculture there is a current preference for biofilters and drip units, while biofilters and bioscrubbers are preferred in industry. Such plant already largely satisfy demands on purification performance and reliability. Further development in the direction of even higher performance and more compact plant is expected.
Die Bedeutung der Biotechnologie für die industrielle Chemie
Authors: Harnisch Heinz , Wöhner Gerhard 
Published: December 2004

AbstractThe significance of biotechnology for industrial chemistry. In the next few decades biotechnology will bring about fundamental innovations in the fields of health, nutrition, and agriculture as well as in important branches of industrial production, such as chemistry, which may well be comparable in importance with the present revolutionary technical progress based on electronics. Justification for these forecasts comes mainly from pioneering scientific advances in the fields of molecular biology, biochemistry, and microbiology. Particular mention should be made here of the fascinating potential of genetic engineering methods presently undergoing rapid development. However, less spectacular techniques, such as cell fusion and the immobilization of enzymes or whole living cells on polymeric substrates to give manageable, long‐lived biocatalysts, will also contribute to this wave of innovation. Some of these new developments are now gaining acceptance in industrial production.
Hydraulische Belastungen von Kesselreaktoren
Authors: Kipke Klaus Dieter 
Published: December 2004

AbstractHydraulic loading of tank reactors. According to the present knowledge, the hydraulic loading of agitators, reactors, and internals can be summarized as follows: Hydraulic forces can be represent in dimensionless form with the aid of force coefficients. In the turbulent regime, the load comprises an average value and a fluctuating component. In the case of gasifying reactors, the entire tank can undergo resonance vibration, which can, however, be estimated in advance. Gassing has a subordinate effect upon the hydraulic shaft loading. Strouhal effects may have to be considered with various internals. Resonance effects have already by observed in practice.
Probleme der Modellbildung bei technischen Festbettreaktoren
Authors: Eigenberger Gerhart , Ruppel Wilhelm 
Published: December 2004

AbstractProblems and potential of mathematical modelling for industrial fixed‐bed reactors. Modelling and computer simulation for the purpose of design and operation of industrial fixed‐bed reactors are discussed with the aid of examples. Emphasis is placed upon difficulties and problems arising from the adequate model formulation. The following aspects are discussed in some detail: (1) The influence of heat and mass transport in the catalyst pellet, especially with complex reaction. (2) The relations between radial heat transfer and radial flow profile and its influence upon the axial temperature profile in packed tubes with or without heat generation by reaction. (3) The modelling of activity‐variations along the packed bed during the lifetime of a catalyst. (4) The scale‐up problem of multitubular fixed‐bed reactors, i.e. the problem of achieving and maintaining equal operating conditions inside and outside all the tubes of the bundle.
Zur Ermittlung von Stoffübergangszahlen auf der Basis von Gelöstsauerstoff‐Messungen
Authors: Schumpe Adrian 
Published: December 2004

AbstractDetermination of mass transfer coefficients on the basis of dissolved‐oxygen measurements. Sources of error in the dynamic and the stationary method for determination of mass transfer coefficients are discussed on the basis of experimental results obtained in bubble columns. In particular, the delayed electrode response, the resistance in the liquid film, bubble contacts of the electrode, and the influence of very small bubbles encountered in viscous media have to be considered.
Membranen in der Verfahrenstechnik
Authors: Strathmann Heiner , Chmiel Horst 
Published: December 2004

AbstractMembranes in chemical engineering. In the last 10 years membranes and membrane processes have evolved from a useful laboratory tool to an industrial product of significant technical and commercial impact. In some applications membrane processes have today not only replaced some conventional separation procedures in the chemical process industry, because they are often more economical and yield better quality products, but they have also successfully been utilized to solve mass separation problems where conventional procedures failed or are too expensive. This contribution discusses the state of the art of membranes and membrane processes as well as their major applications, with the main emphasis being placed on more recent developments.
Exergoökonomische Bewertung einer Luftzerlegungs‐Anlage
Authors: Knoche Karl Friedrich , Hesselmann Klaus 
Published: December 2004

AbstractExergoeconomic evaluation of an air‐fractionation plant. This article presents a method for minimization of capital investment and energy costs for process plants. To this end the operating parameters are divided into two groups, i. e. into those affecting only the operation of individual components or groups of components and those of importance for operation of the entire plant. Optimization can therefore be undertaken in two steps: (1) optimization of plant components or group of components with regard to the operating parameters of the first group, (2) optimization of the entire plant with regard to operating parameters of the second group. This approach is illustrated by investment cost/exergy loss diagrams.
Pumpen und Verdichter für hohe Drücke — Festigkeit, Dichtungen, Verschleiß
Authors: Vetter Gerhard 
Published: December 2004

AbstractPumps and compressors for high pressures – strength, seals, wear. In high pressure processes pumps and compressors are used for the pressure range of 100 to 4 000 bar. Very careful design is necessary because of the extreme mechanical demands. The special features of high pressure technology are explained. The methods used for generating high pressures – displacement or fluid flow machine – impose design limitations, partly by the final temperature, Mach number, material fatigue, or vibrations. A survey of typical high pressure pumps and compressors shows the range and limitations of application. There is a definite trend to leak‐free systems. The best design of thick‐walled components with pulsating pressureload avoids grooves, requires smooth surfaces, and uses tough, clean, and high‐strength steels. The various designs of dynamic seals are explained and the state of the art is depicted. Detailed reference is also made to the exceptionally difficult wear problem of oscillating pump valves with abrasive suspensions.
Informationsaufgaben bei der Anlagenplanung
Authors: Lang Gerhard 
Published: December 2004

AbstractInformation policy in planning of plant. An account of the principal concepts of plant planning is followed by a description of the relationship between operator, planner, and periphery with their respective tasks and requirements. Execution of the tasks requires not only purposeful coordination of various engineering disciplines by the planner for mastery of technical questions, but also mastery of a complex organization to satisfy various information requirements of all institutions participating in plant planning. The planning results are divided as the output of individual planning functions into information categories with their data elements. Methods are presented for managing the rapidly swelling flood of information involved in planning with increasing demands on productivity, quality, and comprehensibility.
Expertensysteme – ein Hilfsmittel der Prozeß‐Synthese
Authors: Erdmann Hans‐Horst , Lauer cand. Inf. Michael , Passmann Michael , Schrank Eva , Simmrock Karl Hans 
Published: December 2004

AbstractExpert systems for process syntheses. Commercial programs used in computer‐aided development of chemical processes need a process flowsheet as starting point. Preparation of flowsheets is based largely on human experience, an uncertain kind of knowledge expressed by heuristic rules. These rules are recognized as true and advantageous in most cases without having the validity of a law. Logic programming languages derived from research on artificial intelligence are proven tools for handling heuristics with so‐called “expert systems”. The flowsheets proposed by the expert system reduce all theoretically possible results to a few structures. The example of structuring distillation sequences illustrates what can be expected using an “expert system” in the area of “problem solving” by comparing its proposed sequences with optimized problems.
Koaleszenzprobleme in chemischen Prozessen
Authors: Berger Rosemarie 
Published: December 2004

AbstractCoalescence problems in chemical processes. Separation of liquid/liquid dispersions is a process step which often gives rise to considerable difficulties on an industrial scale. A number of selected examples taken from chemical processes demonstrates where phase separations occur, the consequences they may have, and what industrially practicable methods are available for their solution. The problem analysis presented starts from the mechanism of generation of the dispersion and leads to a qualitative characterization of the various coalescence problems without presuming any knowledge of the droplet spectrum. This procedure acquires important knowledge from an assessment of prior process steps. Measures for improvement are deduced from the causes of poor phase separation: modification of physical properties, change of dispersion, use of mechanical separation aids (packings, coalescing filters), application of an electrical field, centrifuges and hydrocyclones, coalescence‐promoting chemical additives. Industrially applicable methods are reported for design of equipment for implementation of these approaches.
Die Bedeutung von Spalten zwischen Rohren und Rohrboden für das betriebliche Verhalten von Wärmeaustauschern
Authors: Achten Norbert , Herbsleb Günter , Wieling Norbert 
Published: December 2004

AbstractImportance of crevices formed between tubes and tube plate for the operational behaviour of heat exchangers. It must be guaranteed by construction and manufacture of heat exchangers that primary and secondary medium are completely separated from each other. When this requirement is fullfilled, the operational use of heat exchangers can be impaired by corrosion reactions within the crevice formed between tube and tube plate which may result in corrosion damage. The various techniques which are in use to connect tubes and tube plate and which are described in the present report, must be valued with respect to the tightness of the connection as well as to the formation of crevices between tubes and tube plate. Corrosion resistant copperbase alloys and stainless steels are the most important materials which are in use for the construction of heat exchangers. The mechanisms of crevice corrosion with unalloyed and low alloy carbon steels, stainless steels, and mixed connections between tube and tube plate with these materials are described in detail. Crevice corrosion may be caused also by the formation of galvanic cells between materials of differing electrochemical response. Furthermore, the concentration of aggressive media in crevices between tubes and tube plate can lead to corrosion damage of heat exchanger tubes. For the service operation of heat exchangers without any hazard of corrosion damage in crevices between tubes and tube plate, such crevices must be avoided by proper construction and manufacture. As a model for suitable measures to avoid crevices, the manufacture of steam generators for PWR's is described.
Wirtschaftliche Einsatzbereiche von Wärmepumpen‐ und Mehrstufenschaltungen in der Rektifiziertechnik
Authors: Lüdeker Heiner , Gelbe Horst 
Published: December 2004

AbstractEconomic applications of heat pumps and of multi‐column heat integrated systems in distillation processes. The influence of relevant parameters (e.g. relative volatility, flow rate, pressure) on the economics of distillation plants involving heat pumps and heat integrated columns is simulated by a computer program. The different structures of possible energy supply (cogeneration heat‐power plant, direct heating) have been taken into account in the models employed. The areas of economic application of the various energy conserving systems are shown in diagrams. These allow a preliminary selection of the most economic variant. The application of heat pumps outside the field of cryogenic engineering is restricted to some special cases like the separation of closeboiling mixtures. In those cases, where a minimum plant size and steam price is exceeded heat integrated columns promise an economic advantage, provided that cheaper configurations of direct heat recovery are impossible.
Prozeßvergleich von Umkehrosmose und Elektrodialyse am Beispiel der Nitrat‐Entfernung aus Grundwässern
Authors: Rautenbach Robert , Kopp Wilfried , van Opbergen Gert , Peters Thomas , Hellekes Rainer 
Published: December 2004

AbstractComparison of reverse osmosis and electrodialysis for removal of nitrate from groundwater. Reverse osmosis and electrodialysis are membrane processes suitable for desalination of aqueous solutions. Both processes were tested on a pilot scale in a waterworks for removal of nitrate from groundwater. A combination of the processes was also considered with a view to very high concentration of the residual water. The article shows how information gathered from long‐term reverse osmosis trials and the experiments with the electrodialysis plant with industrial membrane dimensions can provide a basis for safe design of large plants. Treatment costs for large capacities are shown for the example of the above feed water. The advantages and disadvantages of reverse osmosis and electrodialysis are compared. This comparison demonstrates fitting applications of the two processes in other areas (chemical industry, sewage treatment).
Der Durchbruch in Adsorptions‐Festbetten: Methoden der Berechnung und Einfluß der Verfahrensparameter
Authors: Kast Werner , Otten Wilhelm 
Published: December 2004

AbstractBreakthrough in adsorption beds: Methods of calculation and influence of operation parameters. Calculation of the breakthrough curve of a fixed bed adsorber is performed numerically for industrial applications. Calculation methods are known for solution of the four coupled differential equations and can be performed within a considerable but acceptable time on todays powerful computers. Nevertheless, the present article considers the analytical description and discussion of the individual parameters because the influence of the large number of parameters on the breakthrough curve cannot be appreciated. These relations must be known if individual operating parameters are changed or if a laboratory unit is scaled up to an industrial plant. The influence of the following effects on the breakthrough curve are considered and approximate solutions are given in order to at least estimate the influence: axial dispersion; shape of the isotherms (linear, Langmuir, irreversible), constant pattern conditions; resistance to mass flow (diffusion and transfer); multicomponent adsorption; concentration and temperature fronts; non‐isothermal adiabatic adsorption; adiabatic equilibrium curve (sorption pathway). Mathematical treatment necessitates reference to the literature. The relations of importance for plant and design are presented here.