bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamik und Stabilität verfahrenstechnischer Prozesse
Authors: Eigenberger Gerhart 
Published: May 2005

AbstractDynamics and stability of chemical engineering processes. Peculiarities of dynamic behaviour as well as stability phenomena in the field of chemical engineering are reviewed with emphasis on the stability of single evaporator tubes and on the stability and dynamics of chemical reactors with strongly exothermic reactions. It is shown that the basic behaviour can be explained in both cases by fairly simple considerations. Some new aspects of general stability theory are also discussed briefly.
Möglichkeiten und Probleme der Prozeß‐Synthese
Authors: Erdmann Hans Horst , Kussi Jürgen , Simmrock Karl Hans 
Published: May 2005

AbstractPossibilities and problems of process design. In times of economic constraint the necessity of optimization of processes means that process design becomes increasingly important as methodical and automated approach to process developments. The present contibution considers some examples of process design, together with their methodological realization and also examines the attendant, partly unsolved problems.
Elektropolieren von nichtrostenden austenitischen Stählen
Authors: Risch Karl 
Published: May 2005

AbstractElectropolishing of stainless austenitic steels. Electropolishing of pressure vessels made of clad steel surprisingly ran into considerable difficulties. A study revealed various reasons for the unsatisfactory polishing results achieved with stainless austenitic steels; e. g. nitride stabilizers lower the polish. The best results were obtained with steels having a low carbon content (C ⩽ 0.030%) when in the solution annealed state. This requirement is not fulfilled in the case of clad sheet. In such cases the C content must be limited to ⩽ 0.020% if a useful result is to be achieved at an economic price. Moreover, a sufficiently thick layer must be removed prior to electropolishing. A report of the study is accompanied by a description of the practical procedure and the theory of electropolishing.
Erfahrungen mit der Auswahl, Einführung und Anwendung von CAD‐Systemen in der Anlagenplanung
Authors: Lang Gerhard , Kreher Raimund , Wolski Hans‐Richard 
Published: May 2005

AbstractExperience gained in the choice, introduction, and application of CAD systems in plant engineering. Computer‐aided design in plant engineering is not restricted to technical or chemical engineering calculations but is also used for the creation of graphic design documents. A standing working party „Computer‐aided plant design”︁ of DECHEMA covered the topic of computer‐aided design systems in its sessions of 1982. The presentations are reported here in short form. After an introduction to the problems concerned, the selection, preparation, and use of computer‐aided design systems are discussed.
Neuere apparative Entwicklungen bei Gewebe‐ und Faserfiltern
Authors: Flatt Eth/Sia Werner 
Published: May 2005

AbstractNew developments in fabric and fibre filters. Design improvements in filters and washing systems have prolonged the intervals between maintenance, increased operational reliability, and enhanced availability. The scope and relationships for special designs, explosion‐proof filters, and two‐stage filtration are indicated, and information is given for dimensioning and cost estimation of filters.
Untersuchung der Durchmischung in kontinuierlich betriebenen Reaktoren mit Hilfe von chemischen Reaktionen
Authors: David René , Lintz Hans‐Günther , Villermaux Jacques 
Published: May 2005

AbstractStudy of mixing in continuous reactors using chemical reactions. Competition between convection, chemical reaction, and mixing phenomena in continuous reactors leads to different limiting cases of micromixing which can strongly influence conversion and selectivity. After the description of these limiting cases it is shown how micromixing in reacting systems can be studied experimentally by the use of chemical methods. The various chemical reactions used so far in these studies are summarized and the aims of future work are briefly outlined.
Einfluß der Agglomeration auf die Filtrierbarkeit von Suspensionen
Authors: Koglin Bernd 
Published: May 2005

AbstractInfluence of agglomeration on the filtering properties of suspensions. In various kinds of filter processes, agglomeration of the particles to be separated is essential for economic operation. Important parameters are the size, porosity, and consistency of the agglomerates, for which a special measuring technique has been developed. The influence of these parameters in various filter processes is described. The physicochemical fundamentals and the chemical engineering of agglomeration in suspension are presented, and the influence of flocculants discussed.
Verbrauchssenkung für großtechnische NH3‐Anlagen durch Wärmerückgewinnung im Abhitzesystem
Authors: Weber Hermann , Graeve Heinz W. , Herbort Hans‐Joachim , Marsch Hans‐Dieter 
Published: May 2005

AbstractEnergy savings in industrial NH3 plant by heat recovery in the waste heat system. Minimization of energy consumption is nowadays a primary goal in the design of NH3 plant. In this context two aspects are particularly important: first, the process steps and their combination must be selected in such a way that the level of energy that has to be supplied to the plant is kept low from the very beginning; second, heat recovery must be optimized by the choice of process conditions and use of appropriate equipment. An industrial NH3 plant built according to these principles can operate at a consumption of as low as 29.5 GJ/t NH3, using proven processes and equipment. The first plant of this new generation with a capacity of 1120 t/d is currently under construction for Canadian Industries Ltd. (CIL) in Canada.
Sichere Druckwasserstoff‐Logistik — Speicherung und Transport
Authors: Baumgärtner K. , Kesten M. 
Published: May 2005

AbstractSafe handling of pressurized hydrogen – storage and transport.For the necessary future transition to non‐fossile energy sources hydrogen is considered to be the ideal energy vector and will therefore assume ever‐increasing importance. However, safe handling of the gas will be a basic requirement. A particular difficulty with pressurized hydrogen is its relative incompatibility with many materials which are commonly used for pressure vessels, either for transportation or for storage. The paper summarizes the major factors instrumental in hydrogen embrittlement. In particular, it stresses the role played by service conditions and by the quality of the internal surface of the vessels when exposed to the gas. On the basis of these findings a number of recommendations are given with respect to vessel design and operating measures in order to secure safe working with high pressure hydrogen gas.
Die verbrennungstechnische Entsorgung eines Chemiebetriebes
Authors: Hüning Werner , Nentwig Hermann , Gockel Claus 
Published: May 2005

AbstractIncineration of waste from a chemical facility. Waste from chemical plants includes solids, liquids, gases – all of which require disposal. Solid and liquid wastes can be readily incinerated or deposited in a central plant. Gas purification is the final step of the process, performed at a limited distance from the production plant. If several substances having different properties are involved then thermal waste air purification is appropriate. This paper considers the design concepts of such a thermal waste air purification unit.
Kenntnisstand und Entwicklungslinien der Schüttgutmechanik
Authors: Molerus Otto 
Published: May 2005

AbstractMechanics of particulate solids – state of the art and current trends. Beginning with the pioneering work of Jenike during the fifties, the mechanics of particulate solids has been developed further to such a state of the art that the behaviour of cohesive powders is understood from the standpoint of particle interactions. Particle interactions can be quantified by evaluation of shear tests, and the behaviour of certain types of systems is now predictable. Three major tendencies can be identified in current developments in the mechanics of particulate solids: the attempt to apply results derived in subregimes to describe more general properties of the particulate solids; the quantitative description of the flow – particle interactions in the presence of adhesion forces; and the investigation of rapidly moving particle layers.
Fouling von Wärmeübertragungsflächen
Authors: Bohnet Matthias 
Published: May 2005

AbstractFouling of heat transfer surfaces. Fouling of heat transfer surfaces in industry causes considerable costs. Overcoming fouling is therefore essential for technical and economic reasons. Solution of the problems requires a better understanding of the physical, chemical and biological processes causing fouling. It is shown, that the prediction of the fouling behaviour of heat transfer equipment based on existing mathematical models is not jet satisfactory. This article presents a new physical model describing particulate and precipitation fouling based on the assumption of a deposition and a removal process. Experiments to prove the results of the theoretical considerations were carried out using an aqueous CaSO4 solution. The test unit which is also suitable for in‐situ measurements is described in detail. Measured and predicted asymptotic fouling factors agree with acceptable accuracy.
Grenzflächenphysik in der Verfahrenstechnik – Beispiele aus der Praxis
Authors: Menold Richard 
Published: May 2005

AbstractInterface physics in chemical engineering – practical examples. A series of practical examples is used to demonstrate the possible ways in which interface physics can help the chemical engineer in his work. The article first presents some fundamental principles of interface physics and appropriate methods and model concepts. It is then shown how this armamentarium can be profitably applied in specific cases: questions of coating, formulation, adhesion, granulation of powders, production of trickling films, and flotation are considered. It becomes very clear that interfacial effects have a very wide and far‐reaching influence on industrial processes. The problems encountered can be solved only by close cooperation between chemical engineers and interface physicists.
Rückgewinnung von Metallen aus niedrigkonzentrierten Lösungen
Authors: Marr Rolf , Draxler Josef 
Published: May 2005

AbstractRecycling of metals from low concentrated solutions. A review is given of processes used for the separation of metals from aqueous solutions, especially low concentration waste waters. Purification processes for waste water used only to reach values set by law are compared with processes that allow recovery of metals. Precipitation with and without additives, adsorption, processes with ion exchange resins, solvent extraction and membrane processes, especially liquid membrane permeation, are described. As a result of these considerations, a qualitative comparison of all the described processes becomes possible. For the separation of zinc from a waste water stream, a special economic comparison is also shown between precipitation processes and the liquid membrane permeation process. Finally, the latest developments in the fields of solvent extraction and liquid membrane permeation are discussed.
Desaktivierung von technischen Silber‐Trägerkatalysatoren für die Herstellung von Ethylenoxid
Authors: Schwarzmann Matthias , Mroß Wolf‐Dieter , Böhning Karl‐Heinz 
Published: May 2005

AbstractDeactivation of industrial supported silver catalysts for ethylene oxide production. In view of the model character of the reaction and the unique nature of the catalyst system, it is of interest to study the deactivation behaviour of technical supported silver catalysts for the production of ethylene oxide. In the present study the influence of the catalyst components support, silver, promoter and inhibitor upon the deactivation behaviour is described. The results of chemical, physical and technical investigations of various catalysts and catalyst components are presented. The investigations show that a decrease in the surface area of the exposed silver and increased deposition of chloride are responsible for catalyst deactivation. The possible influence of alkali promoters is discussed and modifications to the catalyst which have been described in the literature as influencing the deactivation are also evaluated.
Radioaktive Indikatormethode in der chemischen Verfahrenstechnik
Authors: Seher Albrecht , Dorn Ingo Helmut , Engelhardt Hubert , Gruber Wolfgang , Maichel Karl Walter 
Published: May 2005

AbstractThe radioactive tracer method in the chemical industry. In the chemical industry the radioactive tracer method has become a method of analysis with a variety of applications, which range from determining traces of biologically active substances to process analysis in production plants. Process analysis, for instance the determination of residence‐time distributions or of intermingling of streams of different substances, can be carried out under widely varying operating conditions. If the streams of material are labelled with gamma‐ray emitters the distribution of the tracers can be determined by means of detectors outside the plant. To demonstrate the possible applications of the method to process analysis, measurements in three different plants are described. Exhaust gases were labelled with Ar‐41 to determine the residence‐time distribution in plant for the combustion of waste residues consisting of a rotary tube furnace, an afterburn chamber, and a waste‐heat boiler. The waste water entering the activation tank of sewage‐treatment plant was labelled with Na‐24 to determine its residence‐time distribution. Individual particles labelled with Mn‐56 were used to investigate mixing of the powder in the stirred‐bed reactor of a polypropylene plant. The knowledge gained from these measurements has contributed to optimization of existing and planned plant.
Geschichte der Regelung und Automatisierung in der Verfahrenstechnik
Authors: Canavas Constantin 
Published: May 2005

AbstractHistory of Control and Automation in Chemical Engineering. Control and automatization have been associated with chemistry and chemical engineering since long before the present information era. Since the early history of mankind precedents of what were to be called unit operations have been closely associated with control and automation concepts. The history of these concepts illustrates the development of theory and practice from the classic Greek times through Islamic and European Middle Ages up to today's chemical engineering. It also demonstrates the close interdependence of such development with leading social and scientific concepts, education systems and economic conditions.
Untersuchungen zur Trennung von Gasen an mikroporösen Membranen
Authors: Neumann Bernhard , Futterer Eberhard 
Published: May 2005

AbstractStudies of Gas Separation on Microporous Membranes. The composition of Gas Mixtures can be influenced with the aid of microporous membranes by exploitation of the Knudsen effect. The components of lower molecular mass are enriched in the permeated gases while the components of higher molecular mass are concentrated in the retained gases. The best separation is achieved at higher Knudsen numbers. The maximum achievable separation factor is limited by the molecular mass ratio. Hence the gas components in the permeate can be enriched or depleted but never completely separated. In the present experiments, separation factors up to 1.39 and enrichment factors up to 1.10 were attained. However, these values should be substantially improved on use of surface modified porous membranes. Use of ceramic membrane materials permits use of this separation mechanism at very high temperatures.
Organische Reaktionen ohne Lösungsmittel
Authors: Epple Matthias 
Published: May 2005

AbstractOrganic Reactions without Solvent Reactions involving organic solids are of both fundamental and applied importance. First, they provide a basis for understanding structure‐property relationships in crystalline materials, and secondly, they offer opportunities (as yet largely under‐exploited) for environmentally‐friendly synthetic procedures requiring no solvent. The current state of the art is reviewed with special emphasis on possible practical applications.
Einsatz von magnetischen Mikropartikeln in der chemischen Technik
Authors: Böhm Dirk , Voß Harald 
Published: May 2005

AbstractApplication of Magnetic Microparticles in Chemical Engineering Technology In chemical engineering technology microparticles are used in a diversity of fields. Particles with essential chemical characteristics and additional magnetic properties open new opportunities for developing novel processes in many areas. Separation processes such as adsorption and chromatography as well as reactions with catalysts are especially interesting applications. A high specific surface is advantageous for most of these unit operations. Because of the small size of the particles used their handling is not trivial. The magnetically stabilized fluidized bed (MSFB) is a promising example of a magnetically assisted process. This technology permits design of new processes whose favorable operations conditions lie outside the range of conventional operation. Common to all applications is that the magnetic properties of the particles provide a new free and adjustable parameter for managing the process.
Dämpferückgewinnungsanlagen für Ottokraftstoffe in Deutschland – Verfahrenstechnik aus der Sicht des Explosionsschutzes
Authors: Frobese D.‐H. Dirk‐Hans 
Published: May 2005

AbstractVapour Recovery Units for Petrol in Germany – Process Technology from the Point of View of Explosion Protection.It is a requirement of environmental protection that the vapour/air mixtures formed during the storage, transport and refilling of petrol be collected and that the vapour contained in these mixtures be recovered. By vapour balancing within the distribution chain, the vapour/air mixtures are returned to the distribution depots where they are intermediately stored in vapour tanks, if need be, and processed in vapour recovery and exhaust air cleaning units. The more comprehensive the technical measures of discharging, conveying or processing the vapour/air mixtures of flammable liquids, the greater the problems of explosion protection. In this contribution, petrol will serve as an example to present and elucidate the explosion protection measures to be taken in exhaust air cleaning or vapour recovery units.
GVC‐Fachausschuß „Trocknungstechnik”︁
Authors: Zank J. , Stein J. , Wagner G. R. 
Published: May 2005

AbstractAm 31. März und 1. April 1998 stellten in Magdeburg in der Arbeitssitzung des GVC‐Fachausschusses „Trocknungstechnik”︁ Fachleute aus Industrie und Universität ihre neuesten Forschungsergebnisse auf diesem Gebiet vor. Parallel tagte der GVC‐Fachausschuß „Agglomerations‐ und Schüttguttechnik”︁, über dessen Sitzung schon in der CIT 8/98, Seite 920 bis 922, berichtet wurde. Durch die Überschneidung mit diesem GVC‐Fachausschuß war zudem die Möglichkeit gegeben, im größeren Rahmen Probleme an der Schnittstelle der beiden Fachgebiete zu diskutieren.Der Fachausschuß „Trocknungstechnik”︁ ging in insgesamt 12 Fachvorträgen sowie 6 Postern vor allem auf die Wirbelschichttrocknung und ‐granulation, die Kontakttrocknung, Sprühtrocknung und Konvektionstrocknung ein.
Projections from orbitofrontal cortex to anterior piriform cortex in the rat suggest a role in olfactory information processing
Authors: Illig Kurt R. 
Published: May 2005

AbstractThe orbitofrontal cortex (OFC) has been characterized as a higher‐order, multimodal sensory cortex. Evidence from electrophysiological and behavioral studies in the rat has suggested that OFC plays a role in modulating olfactory guided behavior, and a significant projection to OFC arises from piriform cortex, the traditional primary olfactory cortex. To discern how OFC interacts with primary olfactory structures, the anterograde tracer Phaseolus vulgaris leucoagglutinin was injected into orbitofrontal cortical areas in adult male rats. Labeled fibers were found in the piriform cortex and olfactory bulb on the side ipsilateral to the injection. Notably, the projection to piriform cortex was predominantly from ventrolateral orbital cortex, and was not uniform; rostrally, the projection to the ventral portion of the anterior piriform cortex (APC) was substantial, while the dorsal APC was virtually free of labeled fibers. Labeled fibers were found in both the dorsal and ventral portions in more caudal regions of APC. Most labeled fibers were found in layer III, although a substantial number of fibers were observed in layers Ib and II. Labeled fibers in posterior piriform cortex also were seen after injection into orbitofrontal areas. Taken together with previous reports, these findings suggest that piriform cortex includes multiple subdivisions, which may perform separate, parallel functions in olfactory information processing. Further, these results suggest that the OFC, in addition to its putative role in encoding information about the significance of olfactory stimuli, may play a role in modulating odor response properties of neurons in piriform cortex. J. Comp. Neurol. 488:224–231, 2005. © 2005 Wiley‐Liss, Inc.
Propriospinal fiber connections of the cervical motor nuclei in the cat: A light and electron microscope study
Authors: Matsushita Matsuo , Ikeda Michiko 
Published: May 2005

AbstractPropriospinal fiber connections of the cervical motor nuclei were studied in the cat with the Nauta and the Golgi methods. Synaptic boutons belonging to this fiber system were observed and identified under the electron microscope.Lamina IX of the cervical cord receives a large number of fibers from the short ascending and descending propriospinal tracts but only a very restricted number from the long ascending propriospinal tract. Observations with the Golgi method show that these fibers are collaterals derived from axons ascending or descending in the ventrolateral cord. They are of three types of terminal patterns: Fibers terminating in a confined area of lamina IX with repeated branchings, fibers terminating in a wide area of both laminae IX and VIII with short terminal fibers, and simple, unbranched fibers giving off short terminal fibers to cells of laminae IX and VII.In the cervical motor nuclei, it was found that synaptic boutons containing round vesicles usually form asymmetrical synapses with wide synaptic clefts while those containing flattened vesicles form symmetrical synapses with narrow clefts. There are some boutons which contain round synaptic vesicles and make symmetrical synapses. However, they are invariably associated with wide synaptic clefts. In lamina IX of the cervical cord many axodendritic and axosomatic boutons were found to be degenerate after section of the proprispinal fibers. They were filled with either round or flattened vesicles. A few large boutons, filled with round synaptic vesicles and associated with subsynaptic cisternae, were also seen to be degenerate.