bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Verkokung von flüssigen Kohlenwasserstoffen zur Herstellung von Kohlenstoff‐Produkten
Authors: Marrett Rolf , Stadelhofer Jürgen W. , Marsh Harry 
Published: December 2004

AbstractCoking 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

AbstractEquipment 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

AbstractModel 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

AbstractInfluence 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

AbstractElementary 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

AbstractMathematical 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

AbstractCross 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

AbstractDesign 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

AbstractDemands 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

AbstractMixing 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

AbstractMass 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

AbstractDynamic 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

AbstractUse 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

AbstractStudies 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

AbstractAdvantages 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

AbstractMethods 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

AbstractStudies 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

AbstractOnline 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

AbstractPurification 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

AbstractInteractions 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

AbstractSeparation 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

AbstractPhysicochemical 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

AbstractAerosol 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.