bluuebunny/crossref_metadata_2025 huggingface dataset:
Sichere Chemieanlagen – eine ständige Herausforderung an die Technik
Authors: Schlachter Hans
Published: December 2004

Safe chemical plants – a constant challenge to technology. The general public is increasingly questioning the safety of industrial plants. In the field of chemistry, in particular, the impression is being evoked that especially serious and continually increasing risks are in evidence in chemical plants. To begin with, the present report proves by means of statistical data that such portrayals are not in keeping with the facts. Then the safety concept in the planning and operation of chemical plants is discussed. With the aid of examples the ceaseless and successful endeavours towards achieving ever greater safety are described. Examples from the field of systematic research in industrial safety are also cited. Finally, the report deals with the plant operators' own responsibility, and cooperation with supervisory bodies and governmental control organizations.
Industrielle Anwendung von zeolithischen Katalysatoren beim Hydrocracken
Authors: Gallei Ewald
Published: December 2004

Industrial application of zeolitic catalysts in hydrocracking. For maximum production of gasoline by hydrocracking using zeolite type catalysts two cracking schemes are presented and the operation conditions, feedstocks, yields, and material balances are discussed. The advantages of zeolitic hydrocracking catalysts are outlined. The main catalyst parameters controlling activity and selectivity are described and a scheme for the preparation of zeolitic catalysts is given, which illustrates the superiority of zeolitic hydrocracking catalysts over amorphous ones. Finally, the hydrocracking of residues is reviewed and a typical process together with the product characteristics and yields obtained is described.
Statische Mischer und ihre Anwendung
Authors: Pahl Manfred H. , Muschelknautz Edgar
Published: December 2004

Static mixers and their applications. Static mixers are generally made up of similar, fixed mixing units installed at right angles to each other in series along a tube or a channel. The energy of mixing is extracted from the flow. Twelve different units are presented. The mixing effect in static mixers under conditions of laminar flow is accomplished either by specially designed feed systems, by cutting and twisting, by displacement and distortion, or by separation and expansion. Depending upon the mixer, very different lengths are required to achieve the same degree of homogeneity. Compared with an empty tube, the pressure drop in static mixers is some 7‐to 200‐fold greater for laminar flow and 100‐ to 600‐fold greater for turbulent flow. Static mixers are employed in all areas of chemical engineering for homogenization, for reduction of the resisdence‐time spectrum, and for heat exchange. Since maintenance and wear are negligible, since incorporation frequently requires no extra space, and since they can be used over wide ranges of viscosity, static mixers are being increasingly employed in continuous processes.
Zerstäuben von Flüssigkeiten
Authors: Schmidt Paul , Walzel Peter
Published: December 2004

Atomization of liquids. The process of droplet formation can be represented quite clearly with the aid of dimensionless factors. Thus, clear distinction can be made between dripping, spluttering and atomization for the flow of a liquid through nozzles. In the first two cases laminar flow dominates; droplets of a definite size are formed. Atomization, on the other hand, is conversion of a jet in a turbulent state of flow into a fine spray of droplets covering a wide size range. The most commonly used atomization apparatus include one‐and two‐substance jets, rotation atomizers, and special purpose jets.
Phasengleichgewichte binärer Kohlenwasserstoff‐Gemische
Authors: Wozny Günter , Cremer Helmut
Published: December 2004

Sieben Verfahren zur Berechnung des Phasengleichgewichts binärer Gemische aus Dampfdruckdaten wurden programmiert, umfassend untersucht und die Ergebnisse von Berechnungen für Kohlenwasserstoff‐Gemische diskutiert. Es handelt sich um ein Regressionsverfahren und sechs iterative Verfahren auf der Grundlage der Gibbs‐Duhem‐Gleichung. Die iterativen Verfahren benötigen die Approximation der experimentellen Dampfdruckdaten z. B. mittels cubic splines oder orthogonalen Polynomen. Für die weitere praktische Anwendung der Ergebnisse, z. B. für die Simulation von Trennkolonnen, ist nach der iterativen Lösung der Gibbs‐Duhem‐Gleichung die Regression der Dampfmolenbrüche notwendig.
Adsorption aus der Gasphase — Grundlagen und Verfahren
Authors: Kast Werner
Published: December 2004

Für die Auslegung eines Adsorptionsverfahrens werden Angaben über das Gleichgewicht und die Kinetik benötigt, die in die Massen‐ und Energiebilanzen eingehen und die Durchbruchskurve, d. h. das Beladungsende eines Festbettadsorbers, bestimmen. Die neueren Erkenntnisse über Gleichgewicht und Kinetik vor allem bei der gleichzeitigen Adsorption mehrerer Komponenten und die Auswirkungen des nichtisothermen Ablaufs der Adsorption werden vorgestellt. Die Durchbruchskurve kann auch heute nur unter einschränkenden Bedingungen analytisch berechnet werden, doch sind die physikalischen Einflußfaktoren quantitativ erfaßt und eine – wenn auch aufwendige – numerische Berechnung möglich. Damit ist die Auslegung eines Adsorptionsverfahrens mit einem Aufwand und einer Genauigkeit möglich, die vergleichbar anderen thermischen Trennverfahren sind.
Sonderverfahren der Beseitigung industrieller Abfälle – ihre Auswirkungen und Entwicklungstendenzen
Authors: Schmitt‐Tegge Jan D.
Published: December 2004

Die Menge der Sonderabfälle hat abgenommen. Grund: Steigende Beseitigungskosten und steigende Preise für Rohstoffe und Energie. Daraus folgt die Tendenz zur Wiederverwertung oder zu abfallarmen Technologien. Die Verfahren der Tiefversenkung, Einkapselung und Verfestigung, Verbrennung auf Hoher See und Einbringung/Verklappung auf Hoher See werden behandelt. Die zukünftige Entwicklung in der Bundesrepublik hinsichtlich der Abfallbeseitigung auf Hoher See wird aufgezeigt.
Die Automatisierung von Chemieanlagen mit Mitteln der Systemtechnik – Analysen und Trends
Authors: Schmitt Karlheinz
Published: December 2004

Die Automatisierungstechnik mit Systemen konnte sich durch die sehr großen Fortschritte der Mikroelektronik entwickeln. Unabhängig davon führt eine veränderte wirtschaftliche Situation in der Chemie, die sich durch höhere Qualitätsanforderungen charakterisieren läßt, zu erweiterten Automatisierungszielen, die zu ihrer Lösung wiederum systemtechnische Methoden erfordern. Damit schließt sich ein Kreis, in den noch eine Organisation der für die Automatisierung verantwortlichen Abteilungen und darauf abgestimmte Konzepte, Lösungen und weiterentwickelte Ingenieurmethoden einzubeziehen sind.
Die Bildanalyse als modernes Verfahren der Partikelmeßtechnik
Authors: Hermes Karl , Kesten Ulrich
Published: December 2004

Das Ermitteln von Partikelgrößenverteilungen und morphologischen Eigenschaften disperser Feststoffe im Partikelgrößenbereich zwischen wenigen ßm und mehreren mm in sehr kurzer Zeit läßt sich bei Verwendung eines einzigen physikalischen Meßverfahrens nur mit dem mittelbaren Zählverfahren der Bildanalyse durchführen. Soll ein Bildanalysegerät mit anderen modernen Verfahren zur Partikelgrößenanalyse, z. B. Streulicht‐ und Beugungsspektrums‐Meßgeräten, auch von der Analysenzeit und der aus statistischen Gründen notwendigen Partikelanzahl von > 105 konkurrieren können, muß es in der Lage sein, diese Aufgabe vollautomatisch zu bewältigen. In dieser Arbeit, die als Einführung in das Gebiet der Bildanalyse konzipiert ist, werden daher Meßprinzip und Aufbau von automatischen Bildanalysesystemen beschrieben. Die wichtigsten Elemente werden näher auf ihre Eignung zur Partikelgrößenanalyse hin untersucht, wobei auf die besonderen Bedürfnisse des als Anwender auftretenden Ingenieurs Rücksicht genommen wird. Am Schluß der Arbeit wird das wichtige Problem der Probenvorbereitung für die Bildanalyse erörtert, und es werden Präparationstechniken für spezielle Anwendungsfälle beschrieben.
Entwicklungstendenzen in der Technik katalytischer Fluid‐Reaktionen
Authors: Dialer Kurt
Published: December 2004

Development trends in catalytic fluid reactions. Problems associated with raw materials, energy, and the environment have had many repercussions on the industrial development of catalytic processes. Apart from efforts to increase the use of coal‐based feedstock such as synthesis gas and methanol, particular attention is focussed upon improvements in the selectivity of industrial reactions. There appears to be a reversal of direction in the choice of phase: proven homogeneous catalysts are being heterogenized, and heterogeneous catalysts are being employed in homogeneous or liquid form. Other typical features are increased efforts to replace conventional multistep syntheses by direct syntheses, and high pressure syntheses by medium or low pressure syntheses. Finally, measures designed to regenerate or conserve catalytic activity and selectivity are becoming more and more important.
Zur Auslegung von Strahlsaugern für einphasige Stoffsysteme
Authors: Henzler Hans‐Jürgen
Published: December 2004

Design of ejectors for single‐phase material systems. The principal design data of self‐priming jet devices are presented. A theoretical design model is first discussed which provides a good description of the experimental results reported in the literature. Application of this model requires introduction of empirical parameters which depend solely upon geometry and have been determined for various ejector types from experimental results. An energetic comparison permits estimation of the influence of the individual geometrical parameters on the efficiency. This leads to the concept of an energetically favourable device whose efficiency and suction characteristics are given over a wide range of throughput.
Metallvergütung durch Ionenstrahlen
Authors: Wolf Gerhard K.
Published: December 2004

Finishing of metals by ion beams. For many years ion beams have been used for doping semiconductors. Recently more and more interest has been shown in them as a method for the finishing of metals. The insertion of an alloying element as an energetic ion into a 0.1 to 1 μm thick surface layer of a metal instead of bulk alloying is interesting, especially with respect to a future shortage of resources. In addition, the ion beam techniques (ion implantation and ion beam mixing) provide the possibility of implanting any element in nearly any substrate. This may often lead even to metastable or amorphous surface structures. In this paper the ion beam techniques are described and the resulting materials are outlined. The possibilities for applications in different fields such as corrosion, mechanical surface properties (tribology), and catalysis are illustrated with examples. They range from pure basic science and applied science to potential procedures to be used in industrial production.
Substratspezifische Stoff‐Führung bei anaeroben Verfahren zur Methan‐Gewinnung
Authors: Baader Wolfgang
Published: December 2004

Principles of material flow in anaerobic methane production processes. Rising prices of fossil energy are upgrading the importance of processes for generating fuels from organic wastes and from renewable biomass. Anaerobic digestion is a suitable approach for the production of fuel gas rich in methane from wet or liquid organic feedstock. Depending upon the biochemical characteristics of the digestion process and upon the physical conditions for an optimal mass transport, specific technical solutions have been found for treating typical substrates differing in chemical composition, digestability, and fluid mechanical behaviour; such substrates are waste water, sludges, and organic solids with a high liquid content. A survey is given on the principal systems now used for conducting material to be digested through the whole process and in particular through the bioreactor.
Saubere Luft – technische Möglichkeiten, wirtschaftliche Konsequenzen
Authors: Reh Lothar
Published: December 2004

Clean air – technical possibilities and economic consequences. Starting from the historical development of measures for maintaining clean air in the course of the industrial revolution, the article outlines advances in dust removal which have been accomplished in close, trusting cooperation between legislature, experts and plant operators. The interactions between mankind, technically modified and natural environment, and atmosphere, which have arisen as a consequence of the growth in population, are described and an attempt is made to assign the principal contaminants in the atmosphere to their causers on a global and a national basis. The relationship between rational use of energy and clean air maintenance becomes clear. Additive and integrated air purification procedures are explained with the aid of environmental protection measures adopted in coal‐fired power plant and the costs of excessively low emission level demands pointed out. Examples of gas purification plant in the cellulose industry and the printing trade illustrate the possibilities offered by recycling.
Tropfenabscheider
Authors: Bürkholz Armin
Published: December 2004

Droplet separators. Droplet separators are widely used for purification of process and exhaust gas streams. These separators must be of optimum design to keep the necessary investment and operating costs within limits. This requires a good knowledge of both the droplet size and the fractional degree of deposition of the equipment employed. Extensive studies performed in the past decade have permitted practicable solutions to be found for most of the separation problems involved. Use of suitable parameters provides as means of largely reducing the extensive data to simple deposition formulae.
Die Verkokung von flüssigen Kohlenwasserstoffen zur Herstellung von Kohlenstoff‐Produkten
Authors: Marrett Rolf , Stadelhofer Jürgen W. , Marsh Harry
Published: December 2004

Coking of liquid hydrocarbons for production of carbon products. Apart from the production of metallurgical coke, hydrocarbon mixtures are carbonized especially in conversion of heavy petroleum fractions for production of gasoline and middle distillates; petroleum coke is then obtained. In addition, residues having a high carbon content from petrochemical, oil refinery, and coal upgrading sources are also transformed into high‐quality cokes. The most important process for coking of petroleum‐ and coal‐derived hydrocarbons is delayed coking; in addition, horizontal chamber coking is also employed for coal tar pitch. The principal applications of high‐quality coke products are block‐ and Söderberg anodes for aluminium production, additives and carburizer for the iron and steel industry, graphite products for electrosteel manufacture, and carbon products for special electrolytic processes, chemical plant construction, and electrical engineering. Delayed coking of hydrocarbon mixtures will become increasingly important owing to the modest investment necessary compared to other conversion methods and to the growing share of electrosteel in steel production.
Apparatetechnische Aspekte der Kultivierung von Einzellern in Turmreaktoren
Authors: Schügerl Karl
Published: December 2004

Equipment effects in culturing single‐cell organisms in tower reactors. The influence of the aerator, the aeration rate and the loop and the recirculation rate of liquid through the loop on the performance of tower reactors are investigated. Also the effect of different internals, upward and/or downward as well as countercurrent flow of gas and liquid and the influence of the medium are considered. The performance of equipment can be varied over a wide range by means of these construction and operational parameters. This allows adaptation of these reactors to a particular production process. Difficulties arise when the reactor volume attains very high values. In such cases, fast and uniform distribution of energy, substrate, and oxygen added to the system and the removal of the heat, gas bubbles, and CO2 from the medium cause considerable difficulties. Further investigations will be necessary to develop quantitative relationships for scale‐up purposes.
Modellübertragung in der Verfahrenstechnik
Authors: Zlokarnik Marko
Published: December 2004

Model scale‐up in chemical engineering. Similarity theory and the theory of models based thereon are working tools which permit reasonable planning of experiments, their execution with a minimum of effort, and their evaluation in such a way as to provide reliable information about the design and the operating conditions of the technical plant – provided these methods are used in good time and in the proper manner. A brief introduction to the problems involved and to the methodology of similarity theory is provided by the introductory section and the first example. Four more problems and their solutions according to similarity theory serve to answer questions concerning the size of the experimental scale, the choice of material system used in the experiment, and the problem of scale‐up under conditions of partial similarity. Two of these examples clearly illustrate that an inadequate knowledge of the material parameters (e. g. for foams and slurries) necessitates model measurements on the technical system with a change of scale.
Einfluß der Zweiphasenströmungsbereiche auf die Trenneigenschaften von Siebböden
Authors: Zuiderweg Frederik Johannes
Published: December 2004

Influence of binary phase flow regimes on the action of sieve plates. Recognition of various flow regimes on sieve plates has greatly enhanced our understanding of the mode of action of these plates. When vapour flow dominates the liquid is dispersed into drops; this is the so‐called „droplet regime”︁. In a second principal regime, liquid flow predominates and the vapour is dispersed into small bubbles; this is the „emulsion regime”︁. A transition region exists between these two principal regimes; it is called the „mixed regime”︁. The present paper attempts to demonstrate the relations between the flow regimes and the characteristics of sieve plates. It considers the structure of the binary phase layer, flow over the weir, axial mixing, entrainment of liquid, maximum loading (flooding), and efficiency.
Elementarprozesse bei der Herstellung und Stabilisierung von Emulsionen
Authors: Heusch Rudolf
Published: December 2004

Elementary processes in the production and stabilization of emulsions. When developing new emulsifying agents with a specially low environmental impact, when using emulsifying agents in various branches of industry, and when breaking down emulsions (a very frequent requirement), an understanding of the elementary processes which take place is of great help. The paper provides a comprehensive account of the various elementary processes involved in the production and stabilization of emulsions otherwise scattered throughout the literature. The interplay of the individual elementary processes shows how emulsifying agents and stabilizers differ in their modes of operation. In discussing the structures which occur in aqueous tenside systems, it is pointed out that the swelling of micelles is an elementary process responsible for solubilization and cream formation.
Mathematische Modellierung von Wirbelschichten
Authors: Werther Joachim
Published: December 2004

Mathematical modeling of fluidized bed reactors. In the past fluidized bed reactor modeling has focused on heterogeneously catalyzed gas‐phase reactions. Recently, however, greatly increased activity is obvious in the field of fluidized bed combustion where attempts are made to describe coal combustion in the fluidized bed and emission of sulphur dioxide and nitric oxides from FBC units, with the ultimate aim of modeling the operating behavior of industrial fluidized bed combustors. The present paper surveys the state of the art in fluid bed reactor modeling. The influence of the fluid‐dynamic state of fluidization which is governed by gas and solids properties, fluidizing velocity, and bed geometry, as well as the influence of different zones within the reactor and of design details, respectively, are discussed on the basis of several models described in the literature.
Querstromfiltration
Authors: Fischer Eberhard , Raasch Jürgen
Published: December 2004

Cross flow filtration. Cross flow filtration is a filtration process in which the formation of a filter cake is limited or – under certain conditions – almost completely prevented by flow of the suspension across the filtration surface. For the industrial application of cross flow filtration a variety of apparatus has been developed, at present mainly used for clarifying and thickening filtration, respectively, of slurries containing very fine solids. This is reported on in general terms. In addition, a survey is given of the present state of research in cross flow filtration, including the authors' own work. It is concluded that the present basis for design and optimal adjustment of cross flow filtration apparatus is still rather uncertain, in spite of the fact that such equipment is already being successfully used for industrial purposes.
Beitrag zur Problematik der Auslegung schwingend beanspruchter Bauteile
Authors: Gramberg Ubbo
Published: December 2004

Design of structural components subjected to fatigue load. This survey details the knowledge and experience acquired to date in the field of damage investigations with respect to damage sustained by structural components as a result of fatigue and fatigue combined with corrosion. No matter how much care is taken at the planning stage, a component subjected to fatigue load may suffer premature failure if basic rules relating to construction are not observed, or if there are defects in production engineering. The stress relationships become totally unpredictable for the design engineer if an additional corrosive factor is superimposed. Some of the damage which occurs in various industries could effectively be prevented if design and production engineering aspects derived from knowledge of both these damage mechanisms and from experience of damage analysis were taken into account.
Anforderungen an verfahrenstechnische Anlagen durch die Weiterentwicklung der Gewässerschutz‐Vorschriften
Authors: Braubach Hans‐Otto , Sommer Eicke , Zellmann Karl
Published: December 2004

Demands placed on processing plants by developments in legislation for the protection of water. Initial legislation for protection of water against pollution was limited to general regulations ensuring safe storage of mineral oil products, especially fuel oil. In the course of time, the requirements became more and more detailed and extended to cover all substances representing a potential source of danger to water (not only liquids) and plant serving purposes other than the storage of water‐endangering substances. The developments from the 1. Water Ecology Act dating from 1960 to the state regulations concerning plant for the storage, filling, and transferring of water‐endangering substances are described.
Mischen in Schneckenmaschinen, Teil 1: Homogenisieren
Authors: Pahl Manfred H.
Published: December 2004

Mixing in screw mixers, Part 1: Homogenization. During the treatment of thermoplastic synthetic materials in screw mixers the powder or granular material has to be melted as well degassed, mixed, and delivered against higher pressure. The mixing operations are: Mixing of soluble liquids, suspending of solids in liquids, deagglomeration, mixing of immiscible liquids and mixing of particulate solids. The efficiency of mixing of soluble liquids is poor in conventional single‐screw extruders under low pressure. Additional mixing elements are therefore placed on the screw. The distribution of the components is better in co‐kneaders and multistage screw mixers than in conventional single‐screw mixers. Co‐rotating screws which mesh together show a more careful treatment and more steady mixing of soluble liquids than contrarotating screws. The manufacturers of such continuously working machines are venturing increasingly into the area of reaction technology with treatment of highly viscous materials. A new development is the new programmable reactor.
Stoffaustausch‐Maschinen. Chancen für den Gerätebau und die stoffwandelnde Industrie
Authors: Brauer Heinz
Published: December 2004

Mass transfer machines – opportunities for equipment construction and material conversion industries. The material conversion industry has one of the highest energy turnovers of all branches of industry. Modern mass production was possible only by switching to a continuous mode of operation. The large mass flows require use of a very wide range of process engineering machinery. In the first stage of machine deployment, conveying machines were introduced, i.e. pumps and compressors. In the second stage, numerous kinds of material transforming machines made their entry in the production process (e.g. in mechanical and biological process engineering). Material transforming machines are meanwhile to be found even in the area of heat transfer (Ljungström regenerator) and chemical engineering (stirred and extruding reactors). However, in spite of these introductory successes, the extensive fields of heat and mass transfer and reaction engineering still have to be conquered by appropriate machines. The trend of developments is unequivocal: the future belongs to material transforming machines. Such machines permit economic manufacture of mass products in comparatively small plants. These machines will help us to halt the trend to large scale plant and to replace them by smaller‐volume plant. The fundamental properties of the machines are presented in detail and examined in the case of two examples.
Dynamische Simulation komplexer chemischer Prozesse
Authors: Gilles Ernst Dieter , Holl Peter , Marquardt Wolfgang
Published: December 2004

Dynamic simulation of complex chemical processes. The detailed dynamic simulation of coupled process units in chemical plant is gaining increasing importance as an important tool in plant engineering and operation. This paper deals with basic problems in the development of a universally applicable dynamic simulator. General requirements are formulated. The program package DIVA currently under development is outlined. Simulation of the start‐up phase of a simple production plant as an example demonstrates the mode of functioning and the potential of the simulator. Future work will concentrate on enlarging the model libraries and on increasing the efficiency and ease of use to meet the demands of industrial applications.
Anwendung von Flockungsmitteln bei der mechanischen Flüssigkeitsabtrennung
Authors: Burkert Hans , Horacek Heinrich
Published: December 2004

Use of flocculants in the mechanical separation of liquids. The mechanical separation of liquids from turbid water or sewage sludges depends primarily on the size and density of the suspended particles. The process of separation by sedimentation, filtration, or centrifugation becomes increasingly difficult with decreasing size of the suspended particles and decreasing density difference between solid and liquid. The addition of flocculants in ppm amounts destabilizes the dispersion and flocculation sets in. Thus flocculants agglomerate suspended particles, improve the separation, and accelerate the overal separation process. The synthetic organic high polymers used in the treatment of municipal and industrial waste water are characterized by their chemical composition, their molar mass, and their charge density.
Untersuchungen an dealuminierten Mordenit‐Katalysatoren
Authors: Karge Hellmut G. , Weitkamp Jens
Published: December 2004

Studies on dealuminated mordenite catalysts. Some basic aspects of zeolite structure and chemistry are introduced. Subsequently, an industrially important representative of these porous aluminosilicates, viz. mordenite, is treated in more detail. Particular attention is paid to its dealuminated modifications. The most important techniques of zeolite dealumination are presented in a general way. The effect of dealumination on chemical and physical properties of mordenite is discussed, in particular the influence on Brßonsted and Lewis acidity, adsorption, and diffusion, these being the fundamental phenomena in the context of catalysis on mordenites. Catalytic behaviour of dealuminated mordenites is reviewed with respect to a series of basic reactions including cracking, hydrocracking, and isomerisation of paraffins, dealkylation and disproportionation of alkylbenzenes, as well as coke formation. Correlations between activity and/or selectivity and both chemical and structural properties of dealuminated mordenites are demonstrated.
Vorteile von parallelen Strömen bei Rektifikation, Absorption und Extraktion
Authors: Heucke Christoph
Published: December 2004

Advantages of parallel flow streams in distillation, absorption, and extraction. Under certain circumstances, separating effects in distillation, absorption, and extraction processes can be improved by dividing a phase into several parallel streams. Number of trays, pressure drop, vessel weight, or energy demand can be reduced. Presumably, this principle is also applicable in other counter‐current processes.
Methoden zur Beschaffung von Information über Stoffeigenschaften
Authors: Knapp Helmut
Published: December 2004

Methods of obtaining information about properties of materials. A knowledge of the properties of the materials and mixtures to be processed, and the materials of construction is essential for the process engineering design of plant and for dimensioning machines and apparatus. Inter alia, the thermal and calorific properties and the transport properties of fluid materials, and also the mechanical and chemical‐corrosive properties of the materials of construction should be known. The desired information can initially only be found by experiment. Today it is (still) impossible to calculate the macroscopic properties of substances with the necessary degree of accuracy from the properties of the molecules or even the elementary particles with the aid of (generally imperfect and incomplete) physicochemical models. The microscopic concepts are nevertheless extremely important for setting up correlation equations with which the measured values can be interpolated and extrapolated.
Mikrostrukturuntersuchungen an porösen Feststoffen durch Physisorptionsmessungen
Authors: Seifert Jürgen , Emig Gerhard
Published: December 2004

Studies of the microstructure of porous solids by physisorption measurements. The principal experimental methods for studying the microstructure of porous solids are based on physisorption measurements. The resulting sorption isotherms can yield data such as surface area and pore radius distribution, which are of great importance for development and characterization of porous catalysts. After a brief presentation of available measuring equipment, the main concern of this survey is the evaluation of sorption isotherms. In particular, methods for determining the micropore contribution to the total pore volume and the pore radius distribution in the micropore range are examined critically with regard to their reliability.
Online‐Prozeßanalyse in Bioreaktoren
Authors: Schügerl Karl , Lübbert Andreas , Scheper Thomas
Published: December 2004

Online measurement of bioreactor performance. Recent techniques for characterization of the cell‐reactor system are presented, especially online techniques for measurement of three‐phase fluid properties, for chemical analysis of the composition of the fermentation medium and the gas phase, and for determination of the cell concentration as well as for the evaluation of the intracellular components and the biological behaviour of the cells. Furthermore, optimization of the sampling point and the sensor arrangement for the measurement of the above properties are also considered.
Aufarbeitung Ammoniak enthaltender Abwässer – Verfahrens‐ und Kostenvergleich
Authors: Rautenbach Robert , Machhammer Otto
Published: December 2004

Purification of waste water containing ammonia – Comparison of proces and costs. The present case study compares three processes for reduction of ammonia in liquid effluents with respect to process engineering and treatment costs: stripping with steam, stripping with air, and liquid membrane technology. The specific purification costs are estimated for plant capacities between 1 and 50 m3/h, for NH3 feed concentrations between 50 and 2000 ppm, and for waste water feed temperatures between 5 and 80ßC. Moreover, the NH3 exiting concentration is varied between 1 and 500 ppm. In the standard case, the estimates are based on a decrease to 5 or 50 ppm NH3 in the waste water. Two cases are considered: in one, it is assumed that the ammonium sulphate solution produced by all three processes must be evaporated down to a disposable form. Alternatively, it is assumed that the ammonium sulphate can be used without further work‐up.
Wechselwirkungen zwischen Lebensmittel und Verpackung
Authors: Piringer Otto
Published: December 2004

Interactions between food and packaging. The main criterion for optimizing packaging is to minimize the migration of compounds present in the packaging into the food. This article describes the physicochemical basis of possible migrations in the order of increasing complexity and the principal chemical interactions. The legal consequences of these interactions for the quality assurance of food and for consumer protection are briefly discussed. A guiding principle of food packaging is that the properties of the food and its packaging must be optimally coordinated.
Zerlegung von Dreistoffgemischen durch Rektifikation
Authors: Stichlmair Johann
Published: December 2004

Separation of ternary mixtures by rectification. Ternary mixtures can be separated only to a limited extent by rectification. For example, it is common knowledge that only one pure substance can be separated from a ternary mixture in a single rectification step, and that this substance cannot be the one with the middle boiling point. However, this statement is correct only as long as „normal”︁ boiling behaviour is valid. If one or more azeotropes occur in a mixture then it is difficult to assess the possible separations. This paper presents a systematic method permitting quantitative predicition of possible separations even in very complex systems. The potential of this method for process development is demonstrated for the example of the separation of azeotropic mixtures with the aid of an auxiliary substance.
Physikalisch‐chemische Trennverfahren in der Biotechnologie
Authors: Onken Ulfert
Published: December 2004

Physicochemical separation processes in biotechnology. A number of special features of the work‐up of products of biotechnological processes play a decisive role in selection of a separation process. Thus the products generally have to be isolated from dilute aqueous solutions. Moreover, the substances to be isolated are generally sensitive to external influences such as temperature or pH value and have to be isolated from mixtures with chemically similar compounds. Demands for greater selectivity of separation are met by processes based on differences in molecular structure of the substances to be separated. These include separation methods which have practically no significance in chemical engineering, e. g. chromatographic, membrane, and electrophoretic processes. The development of industrially utilizable processes to exploit the high separation efficiency of the physicochemical techniques requires close collaboration between process engineers and chemists.
Aerosolbildung bei der Absorption und Partialkondensation
Authors: Schaber Karlheinz
Published: December 2004

Aerosol formation on absorption and partial condensation. The phenomenon of aerosol or mist formation on absorption and partial condensation has hardly been investigated but causes serious problems in the practice of industrial exhaust air purification, e.g. in the absorption of hydrogen chloride or on low‐temperature condensation of solvent vapours. The mist droplets formed in these processes remain suspended in the gas phase and lead to unacceptably high pollutant concentrations in the exhaust air. This present study first surveys currently available knowledge and then goes on to explain under what thermodynamic boundary conditions aerosols are formed by certain substance systems. The author also applies known results relating to nucleation and growth mechanisms from aerosol physics to technical processes. It is seen that aerosols with very small droplet sizes, which are difficult to precipitate, are formed particularly during absorption processes.
Tendenzen der Energieversorgung im Hinblick auf die CO2‐Diskussion
Authors: Burkel Wolfgang
Published: December 2004

Energy supply trends with regard to carbon dioxide (CO2). Carbon dioxide (CO2) is regarded as the main cause of the „greenhouse effect”︁ in the atmosphere. Although this problem is well known, the chances for a reduction of CO2 emissions are limited. On the one hand there is no immediate need for action because for the time being the catastrophes are taking place on the computer only. On the other hand population figures and thirst for energy are steadily increasing. Moreover, the possible measures for a reduction of CO2 are limited. Considering the FRG's share of the carbon dioxide concentration, the targeted 25% reduction of CO2 emissions by the year 2005 could be achieved. A large potential of energy saving and CO2 reduction are realized by industrial cogeneration. No further technical development in order to open up this potential is needed because the technically and economically optimal solution is already available with the combined gas turbine process. In order to make use of this potential, the hurdle in the licensing procedure for industrial power plants with an output of more than 10 MW must be removed. In addition, cooperation between the energy supply corporations and industry has to be improved.
Dynamische Prozeßsimulation in der industriellen Praxis
Authors: Wozny Günter , Jeromin Lutz
Published: December 2004

Dynamic process simulation in industrial practice. Dynamic process simulation is gaining in importance in process development and plant design. In addition to simulation tools for steady state calculations and optimization, recent years have seen increased development of software tools suitable for dynamic simulation. In particular, dynamic process models have been developed for various unit operations at universities and in industry. Application of the models includes synthesis and analysis of the control structure, start‐up and shut down, safety assessments, optimization, and training. In addition, dynamic flowsheet programs analogous to the steady state programs were developed. Wider use of these program systems requires increased flexibility, solving procedures, user interfaces, model library, interfaces to external programs, etc. The present article is intended not only to describe the state of the art and describe some typical applications, but in particular to examine the demands placed on dynamic process simulation and the simulators and to delineate the current limitations of dynamic process simulation from an industrial viewpoint.
Prozeßentwicklung: Von der Exergieanalyse bis zur EDV‐gestützten Optimierung
Authors: Streich Martin , Kistenmacher Hans , Mohr Volker
Published: December 2004

Process development: From exergy analysis to computer‐aided optimisation. In processes in which chemical compositions or states are altered, limiting case analyses based on the first and second laws of thermodynamics are often of use during preliminary process analyses. Since the introduction of computers for process calculations exergy analyses can be carried out in a simple way and weak points in initial designs in the sense of the second law conveniently located. It is also possible to use exergy analyses to make product predictions if transferable practical exergy losses are available from past experience. In low temperature and energy technology the use of suitably defined efficiencies have been of use for many years in eliminating less attractive processing routes and thus reducing the number of possible designs to be investigated. For many decades so‐called „Sum Q/T Diagrams”︁ have been used in low temperature processing to visualize and improve temperature profiles in heat exchanger networks. Recently technology has been further developed into „Pinch Technology”︁. At the end of process development comes the final detailed optimization. The expensive and time consuming sequential way of working used in the past is being gradually replaced today with equation‐oriented simulation and optimization tools such as the OPTISIM program. Expert systems, in principal, offer the chance of supporting the chemical engineer during the initial design of complete and complex processes. However, the experience with such systems to date has shown that a practical solution lies a long way into the future.
Abwasserreinigung bis zur Rezyklierungsfähigkeit des Wassers
Authors: Brauer Heinz
Published: December 2004

Waste water treatment for recycling quality. Treatment of industrial waste water is the most effective measure to be taken for the protection of surface waters. This ecological aim must be combined with the economic constraints of industry by designing the industrial process in such a way that production of harmful substances is reduced to an absolute minimum, that transfer of these substances into the carrier fluid, i.e. water, is limited, and that the volumetric flow rate of water required for the overall process is also reduced to the minimum. However, even when all these possibilities which modern process technology offers are successfully applied, a certain amount of harmful substances will still remain in the effluent, causing damage to the environment. This can in the long run only be prevented by developing closed loops for the process water, which include a waste water treatment process, in which mechanical, biological, and physico‐chemical stages are integrated.
Simulation chemischer Reaktionen in turbulenten Strömungen
Authors: Bockhorn Henning
Published: December 2004

Simulation of chemical reactions in turbulent flow. This article considers various methods for the simulation of turbulent reactive flow. The description of such flows by the statistical moments of the fluid‐dynamic and thermochemical variables is discussed at length. The modelling problems in the transport equations for the statistical moments are presented and various approaches are examined, especially for mid‐range turbulent reaction rates, and illustrated with the aid of examples by comparison of simulation with experimental results.
CAPE in der Verfahrenstechnik aus industrieller Sicht – Status, Bedarf, Prognose oder Vision?
Authors: Wozny Günter , Gutermuth Wolfgang , Kothe Wolfgang
Published: December 2004

CAPE in chemical engineering from an industrial viewpoint – Status, demands, outlook. The use of computers for solving chemical process problems is steadily gaining in importance. Simulation, design, optimization, and synthesis of processes are the main applications. The working group “Process simulation and process design” in the Dechema specialist committee “Use of computers in chemical engineering” has discussed the state of the art of simulation tools. Demands of industry on future tools have been outlined and a new simulator concept presented. If this concept is pursued, then interested companies will have to support development. The article presents background information and is intended to stimulate further interest.
Expertensysteme zur Automation von Bioprozessen
Authors: Hitzmann Bernd
Published: December 2004

Expert systems for the automation of bioprocesses. A requirement for the automation of bioprocesses is extensive knowledge – especially practical knowledge. At present this knowledge is supplied by experienced operators during process operation. To process knowledge explicitly with a computer, expert systems are used. So far, there have been only few applications of expert systems for bioprocess supervision and control. This contribution considers the technique of knowledge processing and its application for bioprocess automation. The benefits of expert systems for bioprocess automation are discussed.
Schätzung der Investitionskosten bei der Prozeßentwicklung
Authors: Schembra Mario , Schulze Joachim
Published: December 2004

Estimation of Investment Costs in Process Development. This article gives an overview of plant cost estimating; the corresponding data and authors who have described the individual methods can be obtained from the primary literature. The definitions, the present authors, own data and experience gained in Germany, the pros and cons in practice of each cost estimating method are presented. The turnover ratios, capacity ratio exponents, step‐counting methods, and factor methods are emphasized for cost estimating in a situation of comparative uncertainty in the early stages of a project, because unit cost methods and detailed cost estimating are often used for budgeting.
Auslegung von Kontakttrocknern für rieselfähiges, mit Lösungsmittel‐Gemischen beladenes Trocknungsgut
Authors: Schlünder Ernst‐Ulrich
Published: December 2004

Design of Contact Dryers for Free Flowing Solids Loaded with Solvent Mixtures. Vacuum contact drying of free flowing granular material loaded with a binary volatile mixture (iso‐propanol/water) has been studied experimentally in a bench scale disc dryer of 250 mm diameter. Particle diameters ranged from 1 to 5 mm, the pressure was 1250 Pa and the wall temperature was between 50°C and 180°C. Both the drying rate as well as the selectivity of the drying process could be predicted well by the previously developed so‐called heat transfer penetration model together with vapor phase mass transfer correlations.
Dreiphasenextraktion zur Anreicherung bei der Flüssig/Flüssig‐Extraktion von Carbonsäuren
Authors: Hartl Josef , Marr Rolf
Published: December 2004

Three‐Phase Extraction – Enhancing Enrichment in Liquid‐Liquid Extraction of Carboxylic Acids. The three‐phase extraction process, a new variant of reactive extraction, has been investigated for its applicability in the separation of organic acids. It has been compared with reactive extraction, liquid membrane permeation and supercritical fluid extraction. These processes are based on the use of amine extractants, which have to be dissolved in non‐polar solvents, for the extraction of carboxylic acids, hydroxycarboxylic acids and aminocarboxylic acids. This paper compares the above processes and considers their possible use for acid extraction.
Neue Methoden der Prozeßanalysentechnik für die verfahrenstechnische Produktion
Authors: Hotop Reiner
Published: December 2004

New Methods for Process Analysis in Chemical Production Processes. Process analysis provides methods and techniques for the continuous and automatic measurement of the composition of the substances handled in chemical production processes. Due to the growing automation of the processes and the necessity of on‐line product quality control as well as the increasing demands on safe and environmentally compatible processing the importance of process analyzers has been steadily growing during the last years. Therefore, existing techniques of on‐line analysis had to be improved, new applications have been realized and new on‐line methods have been established. This paper gives some insight into these fields and illustrates trends by means of some examples.