bluuebunny/crossref_metadata_2025 huggingface dataset:
Einfluß von thermophysikalischen Stoffdaten auf die Auslegung und den Betrieb von Destillationskolonnen
Authors: Zeck Sebastian
Published: December 2004

Influence of thermophysical data on the design and operation of distillation columns. It has become common practice in the petrochemical industry to utilize highly developed process simulators for the design of individual pieces of equipment or entire processes. Apart from actual model development, attention focusses on the calculation and use of efficient solution and converging algorithms in the development of such process simulators. Although frequent reference is made to the importance of the underlying material data in the literature and in practical applications there exist only scattered studies giving a suitable choice of the available substance data models and the sensitivity of the process variables to inaccuracy and uncertainty of the material data and the material data models. The present article illustrates the influence of material data (choice of model, sensitivity) for the example of the design and operation of distillation columns and several methods and recommendations are given for fast estimations. With the aid of appropriate examples, the influence of uncertainties in the underlying measured data and the phase equilibrium models on various process variables (plate number, reflux ratio, distillate and sump concentrations) is demonstrated.
Qualitätssicherung in der Feststoffverfahrenstechnik
Authors: Polke Reinhard
Published: December 2004

Quality assurance in process engineering with solids.The properties of solid products depend not only on chemical composition but also on the state of dispersion. The knowledge of the effect of the state on the product quality is necessary for the development, production, and handling of disperse systems. The most important step of quality assurance and quality improvement is to find a way to define the quality of product by objective criteria, allowing a reproducible control based on measurements. After defining the criteria and tolerances for quality assurance, a layout for a reproducible and controllable processing must be developed and realized on a suitable plant. It is important to define quantifiable criteria for the product state in early stages in order to recognize deviations as early as possible. This is necessary to compensate fluctuations by the means of process control. It is not sufficient to do this separately for each process step but the whole process must be considered. Nevertheless a model for the whole process, which is able to describe the correlations between product properties, processing properties, and product quality, should be available in order to recognize the quality‐sensitive parameters.
Kontinuierliche Wirbelschicht‐Sprühgranulation
Authors: Uhlemann Hans
Published: December 2004

Continuous fluidized bed spray granulation. Spray granulation in a fluidized bed can transform originally liquid products (suspensions, melts, solutions) into freeflowing, largely dust‐free granular solids. In the ideal case, the process steps of nucleation, drying/crystallization, shaping, and selective exiting of those particles which have reached the desired size proceed simultaneously in a single unit. The present contribution describes the state of the art of this process as presented in the literature.
Prozeßführung und Verfahrenstechnik zur schadstoffarmen Verbrennung von Abfällen
Authors: Scholz Reinhard , Jeschar Rudolf , Schopf Norbert , Klöppner Gerd
Published: December 2004

Process control and engineering of essentially pollutant‐free combustion of wastes. The avoidance, reduction, and utilization of wastes are recognized as exploitable strategies. In spite of these measures, in the future wastes remain which still require treatment. Combustion is possible way substantially converting complex chemical compounds in an environmentally compatible manner. The present paper deals in a general manner with the possibilities of influencing combustion control (primary measures) for wastes in order to obtain minimum levels of pollutants. A difference is made between gaseous, liquid, or powdered wastes and those comprising mixtures of coarse, pasty, and liquid components. The paper deals with mixing mechanisms, temperature control, burn out, pollutant limitation, and the resulting fundamental possibilities of process control and engineering.
Leckanalyse bei der Anwendung der Störfall‐Verordnung
Authors: Strohmeier Klaus
Published: December 2004

Leakage analysis in application of the breakdown ordinance. The breakdown ordinance places certain demands on safety analysis of chemical plant. An important component of such a safety analysis is accordingly a description of the sources of danger which can trigger a breakdown and information about the effects of a breakdown. In this connection, it is particularly important that not all conceivable sources of danger should be considered but only those which cannot be reasonably excluded. Plant‐based sources of danger of this kind are, e.g., mechanical failure, failure of walls as a result of corrosion, leakage, etc. If the leak cross sections to be expected are known, then the prescribed propagation calculation for a possible breakdown can be performed. The leaks to be expected for various highly stressed plant components such as pipework, vessels, tanks, pipe‐cylinder joints, flanged joints are presented.
Projektierung im Anlagekapitalbedarf von Chemieanlagen
Authors: Fingrhut Helmut
Published: December 2004

Investment capital requirements for chemical plant. In addition to the cost situation, temporary manpower requirements are of considerable importance in the planning of plant, and in this account especially chemical plant. Depending on the kind of plant, estimation of the planning hours is necessary and consideration of specific empirical values lead to the absolute engineering costs. These are usually presented as part of the total capital requirements. On taking recourse to recalculated projects, which have to provide the density function of personnel deployment and diverse cost structures, particular attention must be paid to time‐based changes.
Erfindungsschutz an der Schwelle des EG‐Binnenmarktes
Authors: Laufhütte Hans Dietrich
Published: December 2004

Industrial property protection on the threshold of the european single market. The protection of technical results obtained in research and development is important in order to guarantee the competitiveness of an enterprise. Patents and utility models serve this purpose. There is a plurality of possible parallel ways to obtain protection between which an applicant can choose. Besides the national patent and utility model supranational patent protection may be obtained for a plurality of European states in a common granting procedure, the so‐called European patent. With the advance of the common market common supranational European patent protection is likely to become more important. Setting out from the situation to gain protection in the Federal Republic of Germany these different possible ways of obtaining industrial property protection will be explained.
Die thermische Bodenreinigung am Beispiel ausgewählter Sanierungsfälle
Authors: Fortmann Jürgen
Published: December 2004

Selected cases of recycling as examples of thermal soil cleaning. The term „contamination”︁ is used to describe various soil and water contaminants which may engender considerable risks for the environment and the health of man and animal. Among soil cleaning processes, thermal processes have reached the most advanced development stage. With regard to their efficiencies, they are superior to physicochemical and biological processes. Thermal soil‐cleaning methods are being applied successfully on an industrial scale. The soil is heated in a rotary kiln, and the escaping gas is treated by thermal afterburning and flue gas scrubbing. The plant operated by RUT have capacities of 20–30 and 30–50 t/h respectively. Ruhrkohle's pyrolysis plant with a capacity of 7 t/h is the only German thermal plant operated on an industrial scale. RUT has set up test fields and has proven that soils may be easily recultivated after thermal treatment. The clean‐up of 15 000 to 80 000 t of soil is described. The largest project carried out so far (in Bingen) involved a total order volume of approx. 28 million DM. Comprehensive safety measures and measurements in the environment as well as on the construction site guarantee the protection of the population and the people employed at the site.
100 Jahre technische Alkalichlorid‐Elektrolyse – Technologiewandel unter Umweltaspekten
Authors: Schadow Ernst , Bergner Dieter , Russow Jürgen
Published: December 2004

A century of industrial alkali chloride electrolysis – Technological transformation from an environmental viewpoint. Since the beginning of industrial chemical production, caustic soda and chlorine have represented important basic products in the chemical industry. For 100 years electrochemical processes have been almost exclusively used in the production of these two linked products. The rapid spread and technical development of the processes have been marked by continuous improvement of the individual process steps under the constraints of economic and environmental requirements. The safety and economy of the processes have been improved decisively by a multitude of technical innovations. This is demonstrated most clearly by the reduction in energy consumption. The environmental pollution has been reduced considerably by specific measures. With the newly developed membrane method a process is available today which combines the advantages of the two classical process variations – low power consumption and high product purity – with an exemplary environmental compatibility.
Aerosolabscheidung durch Ionisationswäscher
Authors: Siebenhofer Matthäus
Published: December 2004

Aerosol precipitation by ionisation scrubbers. The precipitation efficiency of an ionisation scrubber was investigated. The design of this type of precipitator is based on the principles of a flat plate film absorber. The scrubbing liquid is continuously distributed on top of the plates by forming the collecting film. The gas, which is saturated with water along the flow straighteners, is led countercurrently to the scrubbing liquid film. Between the plates discharge electrodes are mounted. The objective of this work was the testing of the design and scale up fundamentals. Besides, it was found that there must be a relation between the gas velocity and the electrical discharge field, which is part of the Deutsch equation.
Einsatz von alternativen Reaktionsmedien für eine umweltverträglichere chemische Produktion
Authors: Zlokarnik Marko
Published: December 2004

Use of alternative reaction media for an environmentally safer chemical production. The way in which a chemical reaction is carried out and the composition of the reaction mixture diotate the degree of difficulty of downstream processing operations, not only in terms of energy consumption but also with respect to environmental pollution. A specific environmental protection that is an integral part of the production process must therefore begin with the examination of the chemical rection step. Restructuring a process from a reaction engineering point of view includes two important aspects of which the technical implementation has not yet been systematically examined and which therefore should promise a significant potential for innovation. These are the integration of modern separation operations in the chemical reactor with the aim of shifting the chemical equilibrium and the choice of an alternative reaction medium; although the latter also serves the same purpose, it can bring about a significant reduction in environmental pollution. This aspect is the focus of this paper, in which the advantages of molten salts, supercritical fluids and microemulsions as alternative reaction media are discussed.
Laserspektroskopische Bestimmung thermophysikalischer Eigenschaften transparenter Fluide
Authors: Leipertz Alfred
Published: December 2004

Determination of thermophysical properties of transparent fluids by laser spectroscopy. This review deals with the determination of thermophysical properties of transparent fluids by laser‐spectrometric methods. On the basis of the phenomena of laser‐Rayleigh and laser‐Brillouin scattering the paper demonstrates that the transfer coefficients thermal conductivity, diffusion coefficient, and viscosity, as well as the velocity of sound, sound attenuation, specific heats, and compressibility are fundamentally derivable at thermodynamic equilibrium over a wide range of temperature and pressure. Typical measurements show that the methods used for measuring some of the quantities have already reached standards maturity while others are still in their initial stages.
Laser in der Reaktionstechnik – Analytik und Manipulation
Authors: Wolfrum Jürgen
Published: December 2004

Laser in reacton engineering – analysis and manipulation. In recent years several new linear and nonlinear laser spectroscopic techniques have been developed. The high sensitivity of these methods allows the detection of single atoms and molecules as well as non‐intrusive measurements of concentrations, temperatures and velocities of reacting species in technical processe with high temporal, spectral and spatial resolution in point as well as in multidimensional measurements. Focussing of UV‐ and IR‐laser radiation into a microscope allows manipulation of biological material by a laser microbeam and an optical tweezer.
Transportvorgänge in Festbetten Geschichte, Stand und Perspektiven der Forschung
Authors: Tsotsas Evangelos
Published: December 2004

Transport phenomena in packed beds: History, state of the art, and research outlook. This review tries to give an impression about the history, the state of the art, and the research outlook for heat, mass, and momentum transfer in packed beds. The methodology of model development and experimental analysis is thoroughly discussed on the basis of examples; several postulates are introduced for its codification. This methodology is not restricted to packed beds but can also be applied to other disperse systems with or without chemical reaction. Formulas and guidelines for calculations are not given; handbooks and other related papers are quoted for this purpose.
Zuverlässigkeitsmodelle für verfahrenstechnische Anlagen
Authors: Lorenz Klaus
Published: December 2004

Reliability models of process plants.On the basis of a representation of typical redundant circuits and parameters characterising reliability, the models used for calculation the process plant reliability are explained and compared with regard to their applicability. In particular, the description of partial failures and effects of storage tanks on availability is taken into consideration. The application of reliability models is illustrated by simple examples.
Mikrobielle Sensoren auf Basis von Respirationsmessungen
Authors: Riedel Klaus , Neumann Barbara , Scheller Frieder
Published: December 2004

Microbial sensors based on respiration measurements. Microbial sensors based on the direct contact of microbe and a transducer convert the chemical composition of the sample into a quantitative electrical signal. They are useful for the determination of a wide range of substrates but also of “group effects” for bioprocess control and environmental protection. Starting from the physiological fundamentals – including various ways of influencing sensor performance ‐ this paper reviews the present state of the development of microbial sensors. Different sensor types developed by the authors's group are presented.
Solarthermische Kraftwerke und Erzeugung von Hochtemperaturprozeßwärme
Authors: Becker Manfred
Published: December 2004

Solar‐Thermal Power Plant and the Production of High Temperature Process Heat. A description of the general energy scenario is followed by a discussion of the fundamentals of solar radiation and a discussion of the problems surrounding the coupling of solar energy with technical processes. A number of physical fundamentals relating to efficiencies and temperature are supplemented. The present status of solar‐thermal technology is described for various systems and their components and a comparison made between the possible types of power plants with regard to their annual power production and the power production costs. The author then presents alternatives for the utilisation of solar energy as process heat and for conducting endothermic chemical reactions. The article closes with a brief account of the experimental possibilities offered by the DLR solar furnace at Cologne.
Organische Werkstoffe in Massivbauweise
Authors: Bertelmann Lothar
Published: December 2004

Makromolekulare organische Werkstoffe unterscheiden sich von konventionellen Werkstoffen insbesondere dadurch, daß sie für den jeweiligen Verwendungszweck maßgeschneiderte Eigenschaften besitzen. So begünstigen z.B. die ausgezeichnete Widerstandsfähigkeit gegenüber aggressiven Medien und die relativ hohen mechanischen Festigkeitswerte ihren Einsatz im chemischen Apparate‐ und Rohrleitungsbau. Neue Technologien in der Produktionsgüter‐Industrie und im industriellen Umweltschutz bieten interessante Wachstumsperspektiven für Werkstoffe mit hoher Widerstandsfähigkeit gegenüber korrosivem Angriff bei gleichzeitiger hoher thermischer Belastbarkeit. Herausragende Bedeutung haben in diesem Zusammenhang faserverstärkte Phenolharze und Fluorpolymere als Auskleidungswerkstoffe in Faserverbund‐Konstruktionen. Beanspruchungsgerechte Werkstoffauswahl und Bauteilausführung sind Voraussetzungen für den erfolgreichen Einsatz von Komponenten und Anlagen aus polymeren Werkstoffen.
Welttrend 2000 – Zur Struktur und Eigendynamik moderner Gesellschaftssysteme
Authors: Kernig Claus D.
Published: December 2004

Wohin steuert die Menschheit? Sind katastrophale Fehlentwicklungen unvermeidlich? Kann noch gegengesteuert werden? In vielen Szenarien wurde in den vergangenen Jahren dieses Thema untersucht. Mit Statistiken und der Betrachtung der Wechselwirkung verschiedener Einflußparameter versuchte man, Möglichkeiten zu finden, den heraufzie henden Kollaps zu vermeiden. Die GVC · VDI‐Gesellschaft Verfahrenstechnik und Chemiengenieurwesen widmete auf ihrem Jahrestreffen 1992 in Wien diesem Thema eine Sonderversanstalltung “Welttrend 2000”. Damit sollte darauf hingewiesen werden, daß auch der Ingenieur über seine Tagesarbeit hinaus sich heute mit den globalen Problemen unserer Menschheit beschäftigen muß, und daß er aus seiner spezifischen, naturwissenschaftlichtechnischen Sicht heraus seinen Beitrag zur Lösung einbringen sollte. Professor Dr. Claus D. Kernig, Inhaber des Lehrstuhls für Politikwissenschaft an der Univ. Trier, hielt auf dieser Sonderveranstaltung einen Vortrag, der so viel Anklang fand und so lebhaft diskutiert wurde, daß wir ihn unseren Lesern nicht vorenthalten wollen. Um ein wenig von dem Schwung und dem Temperament des Vortrags zu erhalten, haben wir ihn – entgegen unserer sonstigen Gewohnheit – nicht in einen Bericht umgewandelt, sondern in der Originalform der gesprochenen Rede belassen.
Berechnung des minimalen Energiebedarfs nichtidealer Rektifikationen
Authors: Köhler Jürgen , Pöllmann Peter , Blaß Eckhart
Published: December 2004

Minimum Reflux Calculation for Nonideal Distillations. The minimum reflux ratio is the lower limit of operation for a distillative separation. Due to rising energy costs one is increasingly forced to approach this thermodynamically defined minimum energy consumption. This paper presents an overview of the important methods of calculation published to date. First, a concise physical and mathematical description of the problem is given to introduce the concept of pinch points. These are characteristic regions in separation profiles of distillation columns where an infinite number of stages would be required under minimum reflux conditions. Then, shortcut and rigorous problem solutions for both ideal and non‐ideal mixtures are reported. Ideal mixtures can be computed using the well‐known Underwood equations, which also cover complex column designs (multiple feeds/products, sidestream strippers and enrichers). However, pronouncedly non‐ideal systems still require time‐consuming simulations of columns with a large number of stages. Hence, recent developments attempt to avoid column simulations and to compute pinch points directly.
Verfahrenstechnische und statische Aspekte der Siloauslegung
Authors: Wilms Harald
Published: December 2004

Process Engineering Aspects and Statics of Silo Design. Design of silos for flow is described, starting from the flow profiles developing during discharge. The respective flow profile depends on the flow properties of the bulk solids and on the silo geometry. Based on measured flow properties the determination of the maximum permissible hopper wall inclination to achieve mass flow and of the minimum dimension of the outlet to prevent arching and ratholing is demonstrated, taking into account time consolidation aspects. This yields the size of a feeder and the position of discharge aids. The flow properties are required additionally for structural design of silos. Flow of bulk solids in silos, especially the development of asymmetric flow channels, has a significant influence on the pressure distribution.
Methoden zur Verminderung der Ablagerungsbildung in Wärmeübertragern
Authors: Müller‐Steinhagen Hans
Published: December 2004

Methods for Reducing Deposits in Heat Exchangers. The formation of deposits has long (too long) been considered to be unavoidable and to lie outside the responsibility of the designer. Owing to the enormous operating and investment costs caused by deposit formation and to the development of new processes which are precluded by deposit formation, a number of methods have been developed for reducing or completely preventing the fouling of heat exchangers. The lowest investments are required for chemical fluid processing, which can be retro‐fitted to an existing plant. However, for long term operation with large flow volumes or on use of toxic additives this advantage can shift towards mechanical cleaning processes. Consideration of the reduction of fouling already during the design of a heat exchanger means that it becomes feasible to build much smaller (and hence also lighter) heat exchangers.
Rohstoff‐Recycling und Energie‐Gewinnung von Kunststoffabfällen
Authors: Geiger Thomas , Knopf Hans , Leistner Gerhard , Römer Rainer , Seifert Helmut
Published: December 2004

Feedstock Recycling and Energy Recovery from Plastics Waste. The disposal concept of the plastics industry comprises the following four steps: prevention/reduction, recycling of material (mechanical recycling, feedstock recycling), energy recovery and dumping. Feedstock recycling or chemical recycling stands for the chemical conversion of polymer materials with reduction of macromolecular structure to low‐molecular raw materials. The combustion of plastics waste uses the high calorific value of plastics for energy recovery. This paper describes some of the processes for feedstock recycling and for energy recovery from plastics waste.
Qualitätssicherung im Anlagenbau
Authors: Schmal Wolfgang
Published: December 2004

Quality Assurance in Plant Construction. In recent years plant construction companies have been seeking certification on the basis of the ISO 9000 series of international standards, above all because of the international nature of their business. The present article considers the principal demands made on plant constructors, with special emphasis on customer demands. These concern, among other things, the delivery of the right plant for the given task and the reliability and flexibility of the plant constructor. The main focus is on the establishment of a relationship of trust, project definition, knowledge base, project management, risk considerations and acceptance, data processing, and the development of quality consciousness. The goals of quality production, i.e. adherence to agreed technical criteria, are taken for granted and therefore not discussed in this context.
Phasengleichgewichtsmodelle zur Synthese und Auslegung von Trennprozessen
Authors: Gmehling Jürgen
Published: December 2004

Phase Equilibrium Models in the Synthesis and Design of Separation Processes. While approximately 20 years ago the design of separation processes required expensive and time consuming experiments, modern thermodynamic models nowadays allow a reliable prediction of the phase equilibrium behavior of multicomponent systems using binary data alone. If binary data are not available, group contribution methods can be applied to predict the real behavior. These methods have been developed for the prediction of vapor‐liquid equilibria. The range of application and the reliability of these models were improved by modification of the model, definition of new main groups and introduction of temperature dependent parameters. Especially promising models arise on utilising gE‐mixing rules in cubic equations of state. These models can be applied for the calculation and prediction of phase equilibria of strongly polar systems, including supercritical compounds. At the same time these models allow the calculation of densities, thermodynamic properties, etc.
Kontinuierliche Thermodynamik – ein Weg zur Behandlung komplexer Vielstoffsysteme
Authors: Kehlen Horst , Browarzik Dieter
Published: December 2004

Continuous Thermodynamics – An Approach to the Treatment of Multicomponent Mixtures. In the chemical industry, complex multicomponent mixtures such as petroleum fractions or polymer systems are of great importance. Characterization experiments on such mixtures mostly result only in continuous distribution functions. In contrast, equations of chemical thermodynamics include the mole fractions of the individual components. An approach suitable for overcoming these difficulties is provided by continous thermodynamics, which is based directly on continuous distribution functions. Here, applications relating preferentially to vapor‐liquid equilibrium involved in the calculation of distillation columns are discussed. Continuous thermodynamics is seen to provide distinct advantages over the traditional approach, i.e. the pseudo‐component method.
Zur Fließfähigkeit von Schüttgütern – Definition und Meßverfahren
Authors: Schulze Dietmar
Published: December 2004

Flowability of Bulk Solids – Definition and Measuring Principles. The flowability of bulk solids has to be known for many practical applications. The present paper describes how the flowability is defined and on which physical properties it depends. Experimental determination of the flowability using a shear test is demonstrated. Conditions influencing measuremed results are described. Finally an overview of various methods used for characterization of the flowability of bulk solids is given.
Katalytische Oxidation von Isomaltulose
Authors: Kunz Markwart , Puke Hanjo , Recker Carla
Published: December 2004

Catalytic Oxidation of Isomaltulose. In carbohydrate chemistry the noble metal catalyzed oxidation is known as a “clean” reaction with high selectivity. Applied to the disaccharide ketose isomaltulose, the reaction gives two monooxidized and one dioxidized products contrary to the selectivity rules, which were earned for monosaccharides byHeynsin fundamental investigations. However, the kinetic studies of this reaction show that the dioxidation is a two step reaction in which the second step is inhibited by high isomaltulose concentrations. This could be used for the development of a process of technical interest for preparing the monooxidized products because the continous removal of the ionic reaction products with an electrodialysis allowed the realization of optimal reaction conditions.Kleinet al. show that these monooxidized products are important intermediates for semisynthetic polymers.
Grundlagen für die rechnergestützte Aufstellungsplanung
Authors: Erdwiens Martina , Nipper Norbert , Köster Dirk , Schmidt‐Traub Henner
Published: December 2004

Principles of Computer‐Aided Assembly Planning. The assembly planning for a chemical engineering plant defines the position of the individual machines and articles of equipment in an appropriate grid (Fig. 1). Apart from the demands of pipe routing, numerous widely differing, partly contradictory, boundary conditions influence the assembly of a plant. These include, among other factors, investment and assembly costs, ease of maintenance and operation, as well as safety and environmental protection. Thus numerous specialist areas are involved in this planning work, with the definition of the „optimum”︁ solution being based on individual studies and particularly on experience.
Konversion der Chlorchemie? Eine Wertung der Prognos‐Studie aus Sicht der chemischen Industrie
Authors: Nader Franz W.
Published: December 2004

Conversion of Chlorine Chemistry? Chlorine chemistry is one of the main pillars of the German chemical industry. Conversion of chlorine chemistry should only be considered in cases of urgent ecological or toxicological necessity. However, there are no such reasons. In the Prognos Study, both the assessment of the ecological effects and the economic considerations are based on inadmissible approaches and on incomplete or erroneous, partly outdated literature data.
Zur diskontinuierlichen Rektifikation azeotroper Gemische mit Hilfsstoffeinsatz
Authors: Köhler Jürgen , Haverkamp Hans , Schadler Norbert
Published: December 2004

Discontinuous Rectification of Azeotropic Mixtures with Use of Auxiliary Substances. Batchwise rectification is one of the most commonly used thermal separation operation in the production of fine chemicals and pharmaceiticals, where small amounts of mixtures containing several product or auxiliary components are generally separated. Greater plant flexibility with regard to mixture composition, throughput, and separation specification often also favours batchwise over continuous processing. This publication discusses process engineering possibilities of batchwise rectification of azeotropic mixtures with the aid of various examples. It gives a detailed presentation of two industrial batch rectifications with additional feed of auxiliary substances, viz. azeotropic rectification with entrainment agent and extractive rectification. In both cases the set goal is to minimise charge times and to maximise the quantities processed in plant operation, with time‐optimised control of auxiliary substance throughput being of critical importance in both cases.
Biofouling und Biokorrosion — die Folgen unerwünschter Biofilme
Authors: Flemming Hans‐Curt
Published: December 2004

Microbial layers on interfaces, called “biofilms” are characterized by a polymeric, highly hydrated gel matrix of microbial origin in which the organisms are embedded and immobilized. Biofilms exhibit degradation behaviour different from that free cells and accumulate water, metabolites, and sorbe substances at the interface. They can greatly interfere with technical processes by increasing the fluid friction factor, the hydrodynamic resistance of filter membranes and heat transfer resistance in heat exchanger systems. They can cover surfaces, impart unwanted colour, and contaminate water. Biofilms can attack their support and lead to microbially influenced corrosion (MIC). It is estimated that about 20% to all corrosion damage to metals and building materials is due to microbial influence. Thus, the annual costs of biodeterioration range in billions of dollars. Biofilms play a key role in these processes. They consist of a gel matrix, formed by slime substances, in which the cells are immobilized on the surface of the material. Corrosion is an interfacial process, governed by pH, redox potential, oxygen concentration and other parameters. Biofilms, acting as a transport barrier, may change all these parameters exactly at the site where corrosion takes place compared to the water or air phase surrounding. Thus, a thorough knowledge of the properties and development of biofilms is crucial for the design of effective countermeasures.
Aerosolbildung durch spontane Phasenübergänge bei Absorptions‐ und Kondensationsprozessen
Authors: Schaber Karlheinz
Published: December 2004

Formation of aerosols by spontaneous condensation or desublimation in condensers or absorbers often causes serious problems in industrial processes. The fine aerosol particles, formed under special operating conditions, remain suspended in gases and are carried over into downstream stages or lead to high pollutant concentrations in the exhaust gas. The present paper describe under what conditions aerosols are formed. The characteristic behaviour of aerosols is discussed with the aid of experiments and computer simulation.
Konzepte und Technologien für Mehrproduktanlagen
Authors: Fürer Stefan , Rauch Joachim , Sanden Franz Josef
Published: December 2004

Multi‐product plants are very flexible units which are finding increasing use in the chemical industry, e. g. for the production of fine chemicals, pharmaceutical active compounds and automotive paints. Various concepts have become established for multi‐product plants, depending on the area of use and existing conditions. Technical equipment fitting in with these plant concepts is characterized by standardization, multi‐product suitability and a particularly broad area of use. The paper describes four multi‐product plant concepts and suggests criteria for selecting the suitable concept for a particular case.
Praxisbezogenes Vorgehen bei der Auslegung von Sicherheitsventilen und deren Abblaseleitungen für die Durchströmung mit Gas/Dampf‐Flüssigkeitsgemischen – Teil 1
Authors: Schmidt Jürgen , Westphal Frank
Published: December 2004

The design of an integral safety valve‐ blow‐off pipe system embraces the following essential steps: 1. An incident scenario must first be defined. All reasonable deviations from proper operation of plant must be considered. 2. The flow state at the entry to the safety valve must then be ascertained (one‐phase or binary flow); and 3. the minimal mass flow from the plant component to be protected must be calculated. Independently thereof, it is necessary 4. to determine the mass flow density in the blow‐off pipe system; it is usually related to the cross‐sectional area of the valve seat. The ratio of the two quantities gives the minimum necessary blow‐off cross‐sectional area. 5. In the final step, the pressure drop in the feed line and the counter‐pressure at the valve exit must be examined in order to assure reliable functioning of the valve also in conjunction with the pipe system. Steps 1. to 3. are considered in this article, and steps 4. and 5. will be addressed in Part 2 to be published in this journal. Appropriate recommendations and the necessary equations are given for each step. The main emphasis is placed on applicability of the calculations.
Netzwerktheorie verfahrenstechnischer Prozesse
Authors: Gilles Ernst Dieter
Published: December 2004

The concept of a network theory proposed in this paper provides a basis for systematically addressing questions concerning the design and operation of integrated processes. The route to a problem solution is characterised by the following steps. Modular process structuring takes place on hierarchically ordered levels by switching of components and linkage elements. The process module are switched mass‐ and energy‐wise by means of opposing potential and current vectors. The linkage which is switched one‐sidedly and is hence reaction‐free is a special case. Process modelling utilises modular process structuring and assigns the structural modules to behaviour‐describing modules. Process analysis examiones structural properties (stability, controllability, observability, sensitivity) and nonliner phenomena (ignition and extinction; boundary cycles; waves; chaos) of the overall process behaviour. Process design considers the layout and control of processes from holistic vantage points and aims at optimum determination of the nature, number, and switching of all the components and linkage elements of an integrated process in the light of a given production goal.
Elektrostatisches Zerstäuben von Flüssigkeiten
Authors: Wiggers Helmut , Walzel Peter
Published: December 2004

The electrostatic spraying of liquids is based on electrostatic forces that result from an electrical field and are capable to overcome the capillary forces. In contrast to gravitational and centrifugal fields the value as well as the direction of electrostatic fields depend not only on the setup geometry but additionally on the shape of the liquid surface. This results in a complex interaction between geometries, material properties, and mass and charge currents with respect to the formation of droplets. A capillary tip facing a wide flat counterelectrode has to be considered as the basic geometry. The electrical field needed for droplet production is maintained by a high voltage supply. One has to distinguish between droplet production solely by charge induction and droplet formation influenced by a corona discharge together with an electric wind. Characteristic time constants serve to differentiate between the different spraying modes.
Feststoff‐Fermentation – Ein historischer Überblick
Authors: Vollbrecht Dietmar
Published: December 2004

Under the influence of Buddhism, the oriental peoples for thousands of years took pride in an art of food preparation in which molding is an integral part by introducing boiled or roasted meat notes using solid state fermentation (SSF). SSF was brought to the U.S. in 1914 by Takamine. However, with the advent of submerged fermentation (STF), SSF became almost completely neglected in the Western world. After the World War II, SSF in automatic facilities developed rapidly in Far Eastern countries to attain a present annual market volume of about eight billion dollars. The comparative ease of running SSF bioreactors and particularly their low processing costs and considerably higher yields in comparison with STF suggest that this technology might have considerable economic importance in producing food and pharmaceutically valuable substances.
Übertragbarkeit der in chemischen Anlagen üblichen Sicherheitsbetrachtung auf biotechnische Anlagen
Authors: Lafrenz Bettina
Published: December 2004

The German technical regulation covering safety engineering of hazardous substances (TRGS 300) describes an approach to the consideration of safety in plant handling hazardous substances. No comparable regulation has so far been adopted for biotechnological plant. This article examines the extent to which the fundamental concepts of TRGS 300 might be applicable to biotechnological installations. To this end, the properties of the substances (biological agents and hazardous substances) and the various components of the two kinds of plant are examined. An initial partial transfer of the safety engineering principles and the associated safety requirements of TRGS 300 to biotechnological plant is undertaken. This rather coarse approach does not reveal any reasons why a modified version of TRGS 300 should not be applicable to biotechnological installations.
Prozesse der Reaktivdestillation
Authors: Stichlmair J. , Frey Th.
Published: December 2004

Reactive Distillation Processes Reactive distillation, i.e. the simultaneous implementation of reaction and distillation in a counter–current column, is a promising alternative to the conventional sequential processes. In a preceding paper the effective phase equilibrium of a reactive distillation was studied with a special focus on the determination of so–called reactive azeotropes. In this contribution, a knowledge of these thermodynamic fundamentals is applied to the conceptual design of reactive distillation processes. Furthermore, some process examples of technically important processes are presented.
Innovation und Umweltschutz
Authors: Vahrenholt Fritz
Published: December 2004

Power supply companies and multinational companies have long been accustomed to dealing with scenarios extending as far into the future as the year 2050 – such as the contribution of energy from renewable resources to global energy supplies. In contrast, such concern with the future is painfully lacking in the political arena. It is well worthwhile considering the past when examining the future interplay between innovation and environmental protection. This historical approach demonstrates that environmental protection and technological progress are inextricably intertwined. Solving environmental problems without technology by asceticism and abstention is a rather make‐believe approach. Those who call for cars to stay in the garage usually mean other people's cars, and those who demand rationing of air travel usually mean other people's flights.
Product Engineering am Beispiel extrudierter Instantpulver
Authors: Schuchmann Heike P. , Danner Thomas
Published: December 2004

Product Engineering in the Case of Extruded Instant Powders.

Starch based instant powders are usually produced by cooking/gelatinizing in an excess of water with subsequent drying and milling. Important product attributes are the specific weight and the instant properties of the powder, as well as the taste, the viscosity, and the mouth‐feel of the reconstituted gel. Cooking extrusion is an alternative energy saving process. Process development usually takes a long time and proves expensive due to the large number of different process parameters and their possible combinations. For two exemplary products it is demonstrated how the screw configuration and the target range of process parameters can be defined by statistical trial design. Final optimization („fine tuning”︁) and scale‐up assure efficient process design according to product needs.
Magnetisch stabilisierte Wirbelschichten – Untersuchungen zur Hydrodynamik
Authors: Böhm Dirk , Pittermann Birgit , Voß Harald
Published: December 2004

Zum Andenken an Professor HARALD Voß. Sein Enthusiasmus, seine Kreativität und seine Unterstützung wird seinen Kollegen und Studenten fehlen und stets in Erinnerung bleiben.
Von der Prozeßsimulation zur Lebenszyklusmodellierung
Authors: Marquardt Wolfgang
Published: December 2004

From Process Simulation to Lifecycle Modeling Process simulation is an established technology to support the design and operation of chemical processes. Since this technology has reached a mature state, an obvious question concerns emerging technologies which may succeed process simulation in the future. This contribution attempts to answer this question. The increasing capabilities of mathematical modeling and simulation on various levels of detail increasingly ask for the integration of available but independently developed and applied technologies across the process design lifecycle. Novel computer‐based design support environments are required for this purpose. Such environments need to integrate existing modeling and simulation tools in a workflow oriented manner in order to provide context specific support during the whole design process.
Growth and characterization of LiCaGaF6
Authors: Sani E. , Rabe M. , Reck G. , Becker P. , Roßberg M. , Bertram R. , Klimm D.
Published: December 2004

Optically clear LiCaGaF6 (LiCGaF) single crystals up to 15 mm length were grown by the Czochralski method from CaF2 deficient melts. The substance melts incongruently at 751 °C. No significant deviations of the crystal composition from the nominal stoichiometry Li:Ca:Ga=1:1:1 could be found. X‐ray structure analysis revealed that the substance crystallizes in the colquiriite type structure. LiCaGaF6 is transparent for optical wavelengths >140 – 150 nm. The thermal expansion of the trigonal crystals is α11 = α22 = 18.7×10‐6 K‐1 perpendicular [001] and α33 = 2.7×10‐6 K‐1 parallel [001]. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The crystal structure of high‐temperature α‐CsB5O8 modification at 20, 300, and 500°C
Authors: Filatov S. , Bubnova R. , Shepelev Yu. , Anderson J. , Smolin Yu.
Published: December 2004

The crystal structure of the α‐CsB5O8 high‐temperature modification has been refined by single crystal X‐Ray diffraction at 20, 300, and 500 °C. The structure is based on the zigzag boron‐oxygen layers built up from rigid <2Δ□>‐<2Δ□> pentaborate groups. Cs atoms are located in large cavities of the layer and have nine neighboring oxygen atoms. Five oxygen neighbors are placed within the same layer as the Cs cation; the other four ones belong to two adjacent layers. Thermal stability of the boron‐oxygen triangles, tetrahedra, and pentaborate groups was established. Thermal expansion of the structure observed with the use of high‐temperature powder X‐ray diffraction has sharply anisotropic character: α11 = 27, α22 = 61, α33 = ‐8×10‐6 K‐1. The CsO9 cation polyhedron plays dominating role in bulk thermal expansion of the structure, whereas the high anisotropy is caused by partial straightening of the zig‐zag layer through hinge mechanism. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anomalous creep behaviour of aluminium high current joint materials
Authors: Oertel C.‐G. , Tamm R. , Skrotzki W. , Brokmeier H.‐G.
Published: December 2004

During creep deformation the technical aluminium alloys EN AW‐1350 (Al99.5) and EN AW‐6060 (AlMgSi0.5) under certain conditions of stress and temperature show deformation thrusts of several millimetres, indicating discontinuous dynamic recrystallization. To study this anomalous creep behaviour in more detail the alloys were characterized by global and local texture measurements using neutron and electron backscatter diffraction (EBSD), respectively. In the case of AlMgSi0.5 the main global texture component of the undeformed sample is the cube component. During deformation and dynamic recrystallization a Goss component develops. The grain size slightly decreases with dynamic recrystallization. The normal creep behaviour is characterized by a Norton exponent of 3.8 and an activation energy of 0.5 eV. These parameters indicate that the strain rate controlling process is dislocation creep. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Immunophenotypic differences between diagnosis and relapse in childhood AML: Implications for MRD monitoring
Authors: Langebrake Claudia , Brinkmann Iris , Teigler‐Schlegel Andrea , Creutzig Ursula , Griesinger Frank , Puhlmann Ulrike , Reinhardt Dirk
Published: December 2004

Background

Determination of antigen expression patterns is, in addition to morphologic analysis, essential to the diagnosis of acute myeloid leukemia (AML). The present study was performed to determine (a) the degree of changes in immunophenotype and their consequences on the monitoring of minimal residual disease (MRD) in childhood AML and (b) whether certain clusters of changes in antigen expression patterns exist between diagnosis and relapse.

Methods

Bone marrow specimens of 48 children enrolled in the German AML‐BFM‐93/98 (Acute Myeloid Leukemia‐Berlin‐Frankfurt‐Münster) studies were analyzed immunologically, morphologically, and genetically at diagnosis and at first relapse.

Results

The immunophenotypes by flow cytometry differed by at least one antigen between samples at presentation and relapse in 42 of 48 children (88%). More children displayed an immature phenotype at relapse (43 of 47, 91.5%, vs. 37 of 48, 77%; P = 0.05) with expression of CD34 and/or CD117. This was reflected by a gain of markers that are associated with lineage immaturity in 18 of 25 (72%) of cases, whereas the loss of such antigens was observed in 6 of 25 (24%) patients. We did not observe significant changes for lineage specific markers, with comparable occurrences of loss or gain of myeloid and lymphoid antigens in the sample pairs. Only minimal changes were seen for morphologic and genetic features.

Conclusion

An antigenic shift was observed in 88% of cases in this study. The antibody panels used for MRD monitoring in childhood AML should therefore not be restricted to the immunophenotype detected at presentation but should include in particular markers of lineage immaturity. The clinical observation of a shift toward a more immature phenotype of the myeloblasts is consistent with the model of a clonal evolution of a leukemic stem cell. © 2004 Wiley‐Liss, Inc.