bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oberflächenbehandlungen zur Verbesserung der Gebrauchseigenschaften nichtrostender Stähle in der Chemietechnik
Authors: Protogerakis Emmanuil 
Published: December 2004

AbstractSurface treatment for improving the properties of stainless steels used in the chemical industry. Stainless steels are only able to meet the corrosion resistance demands made on them if their surfaces are in an entirely satisfactory passive state. The final step in fabrication must therefore consist of surface treatments that optimize the performance properties of the parts. Various surface treatment processes are available for stainless steels: pickling, blasting, grinding and brushing. The two last‐mentioned processes are open to objections. Therefore, the main alternative to pickling, which is becoming increasingly problematical for evironmental reasons, is blasting. Provided blasting is carried out with a suitable abrasive (glass beads) and under optimized conditions, it is capable of cleaning the surfaces of the parts entirely satisfactorily.
Polymerisation im Kunststoffbetrieb: Kontinuierliche Polymersynthese und direkte Weiterverarbeitung
Authors: Michaeli Walter , Berghaus Ulrich , Speuser Georg 
Published: December 2004

AbstractPolymerisation in plastics plants: continuous polymer synthesis and direct processing. Use of an appropriate machine concept and a suitable process strategy permits combination of the advantages of anionic moulding masses known from monomer moulding with the advantages of continuous extrusion process. Moreover, coupling of reactive extrusion with direct processing has technically and economically interesting application owing to the low price of raw materials and flexibility with regard to material properties. The molecular structure of the products can be varied within wide limits by way of the formulation of the reactive system. Suitable process engineering can yield molecular masses greater than those of commercially available hydrolytic polyamide moulding masses. The authors' studies and analysis showed the polyamide products produced by reactive extrusion to have properties comparable with those manufactured from commercially available moulding masses.
Möglichkeiten zur Bodensanierung
Authors: Franzius Volker 
Published: December 2004

AbstractPossibilities of soil clean‐up. Abandoned hazardous sites are abandoned waste sites or industrial sites which threaten human health, the environment, or other aspects of public safety. The enforcement of clean‐up of abandoned hazardous sites lies with the Federal German States. Registration and evaluation programmes are underway. Up to now nearly 50 000 suspected sites are registered in the former States of the Federal Republic of Germany and nearly 28 000 in the new states. Calculations of more than 100 000 suspected sites have been made. Several techniques are available for clean‐up which had been funded within the framework of numerous R&D‐programmes. The clean‐up technologies operating in praxis include thermal treatment, physico‐chemical treatment (soil washing and soil venting), and biological treatment. Future trends focus on combined treatment technologies in soil treatment centers.
Von Apollo zu Prometheus und Herakles: Ziele und Methoden der chemischen Verfahrenstechnik
Authors: Prausnitz John M. 
Published: December 2004

AbstractFrom Apollo to Prometheus and Hercules: Objectives and methods of the chemical process engineering. The objectives and the methods of process engineering can be illustrated by comparison with three figures from Greek mythology: Apollo, the spirit and patron of scholarship, particularly philosophy; Prometheus, visionary in the application of ideas, who stole fire from the gods to use it in the service of mankind; and Hercules, who on behalf of all slayed the dragons which tormented mankind. Classical philosophy provides the historical foundation for process engineering (rational thinking which brings order to the chaos of nature); in the same way, contemporary philosophy can serve as the basis for the definition of the role of process engineering in present day society. The central message of modern philosophy (hermeneutics) is the softening of boundaries and devaluation of differences in methods of cognition; reconciliation between the sciences and society, and emphasis of horizontal rather than vertical thinking. These philosophical concepts have direct implications for the training of process engineers and for the development of new chemical products and processes.
Beratungssystem für die Trennung engsiedender und azeotroper Gemische
Authors: Simmrock Karl Hans , Fried Andreas , Welker Rüdiger 
Published: December 2004

AbstractExpert system for the separation of closely boiling and azeotropic mixtures. The formation of azeotropes or the occurrence of closely boiling components in a mixture precludes straightforward rectification as a method of separation. Instead, recourse must be taken to special distillation processes which overcome distillation barriers by admixture of auxiliary substances or exploitation of system‐inherent properties. While the choice of suitable auxiliary substances is almost the only decisive factor in the design of extractive rectification processes, it is difficult to gain an overall view of the numerous variants possible owing to the different distillation properties of azeotropic mixtures. A sound approach is offered by the use of heuristic knowledge in the form of a knowledge‐based expert system to establish the number of possible alternatives satisfying the present state of the art. Starting from a small number of readily available substance and mixture data, rectification processes suitable for the separation of closely boiling or azeotropic mixtures are selected and the corresponding process structures are generated. If necessary, the system initially suggest suitable auxiliary substances satisfying the demands of the special process in question. This paper presents a detailed description of the construction of the expert system for the choice of auxiliary materials and process generation, subdivided into pressure change, homoazeotropic, heteroazeotropic, extractive and multiple azeotropic rectification, the procedural strategy, and the explanatory components of this expert system.
Reaktions‐ und verfahrenstechnische Aspekte der Heterogenisierung homogen‐katalysierter Synthesen
Authors: Luft Gerhard 
Published: December 2004

AbstractReaction and process engineering aspects of transforming homogenous catalytic syntheses into heterogeneous processes.In order to avoid the separation of the catalyst in homogeneous catalytic processes, the preparation of supported phase catalysts has attracted widespread attention in recent years. Most interest has focussed on the immobilization of transition‐metal complexes on solid supports for catalyzing carbon monoxide and olefin reactions. After a survey of the development of solid supported phase (SSP)‐ and supported liquid phase (SLP)‐catalysts two reactions in which SSP‐catalysts have been applied are considered in detail: The carbonylation of methyl acetate to acetic anhydride and the stereoselective hydrogenation of 2‐acylaminocinnamic acid to (S)‐phenylalanine, a derivative ofL‐DOPA. In order to discuss the favourable characteristics and the disadvantages of SSP‐catalysts, they are compared to soluble catalysts. Furthermore, the design of both processes is discussed.
Plattieren — eine kostengünstige Alternative für den Einsatz metallischer Werkstoffe in der Chemietechnik
Authors: Horn Elmar‐Manfred , Korkhaus Jürgen , Mattern Paul 
Published: December 2004

AbstractPlating – a cost‐effective alternative to the use of metallic materials in chemical engineering. The paper treats plated semifinished products used in chemical plant construction. Advantages and draw‐backs of various plating processes such as welding, rolling, or by detonation are discussed as well as post plating processing such as hot forming or joining with regard to measures to be observed. Selection of the most suitable technique should be based on considerations of materials producers, workshops, and chemical plants.
Die Berechnung des Druckverlustes in der dreiphasigen Schwallströmung von Wasser, Öl und Luft
Authors: Herm‐Stapelberg Heinrich , Mewes Dieter 
Published: December 2004

AbstractCalculation of Pressure Drop in Ternary Slug Flow of Water, Oil, and Air. Ternary flow of two immiscible liquids and a gas have hardly been studied up to the present although they frequently occur in petroleum production and in boiling mixtures of liquids. The article first considers known facts about the various kinds of binary flow as limiting cases of ternary flow with special consideration of slug flow. The article then reports new experimental results on ternary flow of oil, water, and air. The frictional pressure drop for ternary flow can be determined with the aid of known calculation procedures valid for binary flow. The limits of the observed forms of flow can be read from a flow map extended to include ternary flow. The pressure drop of ternary slug flow cannot be calculated without a knowledge of the form of flow. The frequency of slug movement is calculated for ternary flow by considering the pressure drop on binary flow of oil and water and the modified slug formation of liquids with higher viscosity. For small volume flows of gas the slug is almost ungassed. The pressure drop can be calculated with considerable accuracy in this range. At higher gas volume flows this becomes possible on considering measured slug lengths.
Entwicklung eines Simulationsprogramms zum Scale‐up von Hydrierreaktoren
Authors: Greger Manfred , Gutsche Bernhard , Jeromin Lutz 
Published: December 2004

AbstractDevelopment of a simulation program for the scale‐up of hydrogenation reactors.The scale‐up of trickle‐bed reactors to pilot and production scale has been difficult and necessitated considerable over‐dimensioning. Therefore a simulation program based on a cell model has been developed in which the dimensions of a cell are directly related to the dimensions of the catalyst particles used. The kinetic equation is formulated with an effective rate coefficient as the only key parameter to be adjusted. With this coefficient the intrinsic rate coefficient, the mass transfer, and the incomplete catalyst particle wetting are considered. The model was applied to the hardening of fatty acids and the hydrogenation of fatty acid methyl esters in laboratory reactors. Comparison with experimental results of pilot and industrial scale is favourable. Thus the model can be used for the scale‐up of trickle‐bed reactors.
Das Zerstäuben metallischer Schmelzen
Authors: Bauckhage Klaus 
Published: December 2004

AbstractAtomization of metallic melts. Among the numerous atomization techniques for melt spraying the principal ones are described and discussed in regard to their design criteria and operating conditions. They can be classified according to the forces acting on the melt stream via the high energy fluid streams (gas or water jets), by ultrasound‐activated vibrations, by impact on by rotating elements. The equations for overall drop size distributions will be discussed. This information is important for optimized production of powders, especially if the median diameters of the resultant particle size distributions are correlated with the operating parameters of the disintegration process. However, this message remains insufficient if no information is given about its standard deviation with regard to the typ of distribution.
Stand der Entwicklung von Füllkörpern und Packungen und ihre optimale geometrische Oberfläche
Authors: Billet Reinhard 
Published: December 2004

AbstractDevelopment of Packings and Their Optimal Surface Geometries – State of the Art. There is a growing demand in industry for contact elements of the kind used in mass and heat transfer processes. It has been responsible for further development of established forms of packing and for new developments in packed beds arranged at random or in fixed geometric patterns. Comprehensive experimental and theoretical studies have revealed the factors that decide the performance of these packings and the limits of their development. It can thus be clearly demonstrated that technical measures impose limits on the improvements in efficiency that can be achieved. On the basis of costs considerations, combined with the results of performance studies, the paper shows how optimum geometric area of a dumped or arranged packings can be determined.
Materielles Recycling thermoplastischer Kunststoffabfälle
Authors: Michaeli Walter , Bittner Muna 
Published: December 2004

AbstractMaterial Recycling of Plastics Waste. The recycling of plastics waste comprises of two main steps, viz. waste preparation and melt processing. Depending on the quality of the waste input and the desired product, the various recycling processes differ considerably in these two steps. For mixed and contaminated plastics wastes, processes are available which, with minimum preparation, process the melt into thick‐walled products. Better defined plastics wastes on the other hand are treated with greater investment in preparation and are generally processed with extrusion into granules for normal plastic processes. Preparation includes shredding, washing and drying, sorting, and agglomeration.
Die Aceton‐Butanol‐Gärung: Grundlage für einen modernen biotechnologischen Prozeß?
Authors: Dürre Peter , Bahl Hubert , Gottschalk Gerhard 
Published: December 2004

AbstractAcetone‐butanol fermentation: basis of a modern biotechnological process? Acetone‐butanol fermentation was performed on a large industrial scale for about forty years. After the Second World War it was unable to compete with petrochemical processes and renewed interest in this fermentation has developed only during the last decade. It has led to a vast increase of our knowledge of the biochemistry of acetone‐butanol formation and of the genetics of the producing organism, Clostridium acetobutylicum. Considerable progress was also made in defining optimal fermentation conditions. However, the biotechnological process is not yet economically feasible, primarily because low final product concentrations engender high product recovery costs.
Erfahrungen mit Mehrproduktanlagen
Authors: Schuch Gunter , König (Fh) Josef 
Published: December 2004

AbstractExperience Gained with Multipurpose Plants. Multipurpose plants are used in many fields of production. Some products often have a short life cycle or are not in continuous demand; hence these plants undergo constant changes. In order to control these changes from an economical point of view, certain boundary conditions must be met. The following article describes which questions have to be asked and answered and which structures prove to be advantageous for such plants.
Dynamik durchgehender Reaktionen in durchmischten Systemen
Authors: Schuler Hans 
Published: December 2004

AbstractDynamics of runaway reactions in well‐stirred systems. The dynamics of the course of reaction plays a prominent role in the safety assessment of chemical reactions: A controlled reaction course differs in essential dynamic features from a runaway reaction. In this contribution the safety assessment of chemical reactions in well‐mixed systems are discussed from the process‐dynamic point of view. The theory of heat explosion, as well as specific parts of chemical reaction engineering, are considered from the process‐dynamic standpoint. The theory of heat explosion, as well as specific topics of chemical reaction engineering are included in this presentation.
Wertstoff‐Rückgewinnung durch Rektifikation und Extraktion
Authors: Villeumier Hartmut , Schlegel Jürgen , Burckhart Rüdiger 
Published: December 2004

AbstractWenn flüssige Nebenströme, hochbelastete Abwässer, verunreinigte Lösungsmittel und Desorbate aus Abluftreinigungsanlagen der Verbrennung zugeführt werden, entsteht zusätzlich zu den Entsorgungskosten auch noch der Wertverlust der enthaltenen Wertprodukte. Da es bei den meisten Produzenten oder Verarbeitern wirtschaftlich und betriebstechnisch ungünstig ist, die bei ihnen anfallenden Gemische selbst aufzuarbeiten, ist das Konzept einer zentralen Aufarbeitung bei einem erfahrenen Lohnverarbeiter wirtschaftlich und ökologisch die beste Lösung zur Vermeidung von Abfällen und für ein sinnvolles Recycling von Wertstoffen. Die Arbeitsweise eines solchen Lohnverarbeiters wird im einzelnen dargestellt und durch Beispiele erläutert.
Forschung in Verfahrenstechnik/Chemieingenieurwesen – Schwerpunkte und Entwicklungstendenzen
Authors: Blaß Echkart , Dialer Kurt 
Published: December 2004

AbstractIn der zweiten Hälfte der 80er Jahre führten auf nationaler und internationaler Ebene Analysen und Empfehlungen für notwendige Forschungs‐ und Entwicklungsaktivitäten zu mehreren Reporten. In der vorliegenden Übersicht werden Zustandekommen, Absichten und Beurteilung dieser Reporte dargelegt sowie ihre Themengebiete und Forschungsziele kommentiert. Es zeigen sich auf dem Gebiet des Chemieingenieurwesens nur wenige Überschniedungen, da die Reporte aus verschiedenen Blickwinkeln ausgearbeitet wurden. Auf dem Gebiet der technischen Chemie erweist sich der DECHEMA‐Report als der umfassendste und ergiebigste. Da er vor allem die chemische Forschung behandelt, wird er hier nur kurz angesprochen. Ein Überblick über tatsächlich beforschte Fachgebiete beschließt die Arbeit.
Nutzung von CO2 aus Rauchgasen für chemische Synthesen
Authors: Kessler Birgit , Eysmondt Jörg Von , Merten Heinrich 
Published: December 2004

AbstractIn diesem Beitrag wird diskutiert, ob durch chemische Verwertung von Kohlendioxid (CO2) aus Rauchgasen die CO2‐Emissionen konventioneller Kohlekraftwerke deutlich gesenkt werden können. Die möglichen Synthesewege zur Verwertung von CO2 und CO (aus CO2 gewonnen) werden anhand von Massen‐ und Energiebilanzen bewertet. Demnach können über chemische Synthesewege nur relativ geringe Mengen an CO2 gebunden werden, da die Jahresproduktionsmengen der in Frage kommenden Chemikalien (z. B. Harnstoff, Essigsäure und Methanol) im Verhältnis zur emittierten Kohlendioxid‐Menge unbedeutend sind. Die endotherme Umsetzung von CO2 zu CO, das bereits in zahlreichen technischen Synthesen eingesetzt wird, erfordert den Einsatz fossiler Energieträger, was wiederum mit einer zusätzlichen CO2‐Emission verbunden ist. Aufgrund der vorliegenden Ergebnisse ist die chemische Verwertung von CO2 aus Kraftwerksrauchgasen bis auf weiteres keine aussichtsreiche Methode zur Senkung der CO2‐Emissionen.
Austragorgane und Austraghilfen
Authors: Schulze Dietmar 
Published: December 2004

AbstractFeeders and Discharge Aids. Feeders and discharge aids have an influence on the flow behaviour of bulk solids in silos. Together with the geometric form of the silo, they are responsible for the operating conditions of a silo. Therefore, feeders and discharge aids have to be chosen and installed under consideration of the flow properties of the bulk solid to be stored. The necessary information is obtained by using the silo design method due to Jenike. This method yields the geometrical data of the hopper (wall steepness, outlet diameter) necessary for a troublefree operation (no doming and ratholing; mass flow; no segregation; uniform flow). Furthermore, the design of feeders and discharge aids plays an important role in determining their function. For example, stagnant zones will build up and cause flow problems on protruding edges and on walls which are not steep enough. For the correct function of the hopper/feeder combination it is important to make sure that the feeder fully activates the hopper outlet and stagnant zones cannot build up. This can be ensured by an appropriate feeder design (increasing capacity in direction of conveying). The driving power of a feeder has to be calculated also on the basis of the flow properties of the bulk solid to be stored.
Belagwachstum am umströmten Rohr
Authors: Riehl Ingo , Kaminski (geb. Heilmann) Silke 
Published: December 2004

AbstractGrowth of Deposits on Pipes in a Field of Flow. The deposition of ash particles on the heat pipes of steam generators represents an energy and safety problem. A deterministic single‐particle model was used to simulate this deposit formation. The numeric solution of the equation of motion gives the distribution of the impact points of the particles on the pipe surface. A particle mass balance allows calculation of the deposit formation δ (φ, t) on a pipe in space and time. Even if only a simple adhesion model is used, the calculated shape of the deposit can approach real deposit shapes. The effect of the sticking probability on deposit shape and formation time is shown. Numeric and analytical studies indicate the existence of stable limiting forms of the deposit. Thus, pipe forms can be calculated which allow only low levels of deposition and erosion. The model can be applied to particle‐fluid flows around other contours.
Ablauf durchgehender Reaktionen sowie Auswahl und Führung von sicheren Prozessen
Authors: Gustin Jean‐Louis 
Published: December 2004

AbstractRunaway Reactions – Their Course and Methods for the Choice and Design of Safe Processes. Literature about runaway reactions is usually concerned with the consequences of explosions such as destruction and emission of hazardous and inflammable substances. DIERS literature describes methods for the design of relief orifices for which experimental studies are necessary. Only few data are available relating to the course of runaway reactions, which, more‐over, are also attributable to variety of causes. The present report describes the various process deviations which can trigger a thermal explosion. In addition, the determination of the necessary data and considerations for risk analysis and for the development of inherently safe processes and for lessening the consequences of thermal explosions are discussed. Any possible dangerous process deviation is illustrated with the aid of examples and experimental data obtained in laboratory experiments. The various dangerous process states which can lead to a thermal explosion are thus subjected to systematic study.
Werkstoffauswahl in der Chemischen Verfahrenstechnik
Authors: Gramberg Ubbo 
Published: December 2004

AbstractChoice of Materials of Construction for Chemical Process Engineering. The choice of appropriate materials is of critical importance for the trouble‐free operation of chemical plant and for economic production. Questions of materials should therefore be considered at an early stage of process development. As a rule, the boundary conditions having a direct influence on the choice of materials are communicated by the process engineer to the materials scientist. Several approaches to the proper choice of materials are usually possible. This choice must ensure that adequate safety reserves are available without making the plant unnecessarily expensive. Although numerous methods are available for determining the properties of materials, testing under operating conditions for specific applications is the optimal approach. The experience amassed by materials experts in practice is an extremely important and indispensable factor because there is much knowledge which cannot simply be expressed in equations and numbers.
Erforderliche Informationsstrukturen für die Qualitätssicherung
Authors: Polke Martin 
Published: December 2004

AbstractInformation Structures Required for Quality Assurance. An information model „quality”︁ is developed on the basis of an object‐oriented structuring of the production process into the two object classes of „product”︁ and „process element”︁. The pertinent product and process properties are represented as set and actual values in property profiles. Particular attention is paid to the scaling necessary or possible for each value representing a property. The histogram has proved to be an appropriate method of representation. Changes in the product‐describing properties occurring during the production process are shown. The information structure selected permits definition of a quality assurance concept and the information and equipment necessary for its implementation.