bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Bedeutung der Chemischen Reaktionstechnik für die Industrie
Authors: Cappelli Antonio , Trambouze Pierre 
Published: May 2005

AbstractNach einem kurzen Überblick über die geschichtliche Entwicklung der chemischen Reaktionstechnik wird der derzeitige Stand der Kenntnisse bei den verschiedenen Reaktortypen behandelt. Dabei wird auch kritisch untersucht, inwieweit die theoretischen Vorstellungen Eingang in die Praxis bei der Auslegung von Reaktoren gefunden haben. Es schließt sich ein Kapitel über die Ermittlung kinetischer Daten und die Entwicklung mathematischer Modelle an. Generell läßt sich sagen, daß außerordentlich viele theoretische Arbeiten von häufig zweifelhaftem Wert für die industrielle Praxis durchgeführt werden. Demgegenüber besteht zumindest auf manchen Gebieten ein kaum zu übersehender Mangel an experimentellen Ergebnissen. Die Erkenntnisse der chemischen Reaktionstechnik werden zur Auslegung von industriellen Reaktoren nur sehr zögernd übernommen. Besonders vielversprechend ist eine intensive Zusammenarbeit von Hochschulforschern mit Ingenieuren und Chemikern aus der Industrie, um die theoretischen Konzepte in der Praxis zu überprüfen.
Stand der Arbeiten zur Wasserstoff‐Erzeugung mit nuklearer Prozeßwärme
Authors: Knoche Karl Friedrich 
Published: May 2005

AbstractDie Nutzung der Kernenergie zur Erzeugung von gasförmigen Sekundärenergieträgern (Synthesegas, Methan und Wasserstoff) hat in den letzten Jahren zunehmend an Interesse gewonnen. Wasserstoff, der wegen seiner vielseitigen Einsatzmöglichkeiten und seiner hervorragenden und umweltfreundlichen Brenneigenschaften als ein besonders attraktiver Brennstoff anzusehen ist, sollte dabei langfristig ohne Verbrauch fossiler Rohstoffe ausschließlich aus Wasser hergestellt werden. Hochtemperaturreaktoren sollen die dazu erforderliche Energie liefern. Einige der aussichtsreichsten Prozesse hierzu werden beschrieben und auf den erreichbaren Wirkungsgrad analysiert.
Langsame Detonation, Dampfexplosion, Blasenresonanz‐explosion – Gemeinsamkeiten
Authors: Leiber Carl‐Otto 
Published: May 2005

AbstractEs werden Explosionsphänomene in kondensierter, vorzugsweise flüssiger Phase beschrieben, bei welchen die Energie „chemisch”︁ oder „physikalisch”︁ eingebracht wird. Es wird gezeigt, daß zwischen der chemischen und physikalischen Explosion keine grundsätzlichen Unterschiede bestehen. Existenzbedingungen der Explosion werden angegeben, welche möglicherweise auch zu deren Unterdrückung herangezogen werden können. Da diese teils außerordentlich kritisch sind, wird diese Art der Explosion derzeitig technisch nicht ausgenutzt, ist aber von sicherheitstechnischem Interesse. Beispielhafte Unfälle werden beschrieben.
Die Anwendung der Risikoanalyse in der chemischen Industrie
Authors: Rose Livingstone Murray 
Published: May 2005

AbstractApplication of risk analysis to the chemical industry. It is surprising that such a well‐established method of investment analysis as risk analysis should find so little use in the chemical industry. A positive feature of risk analysis lies in its ability to influence decision‐making processes prior to their conclusion. Furthermore, it also directs attention to uncertainty factors of a project, which in turn can lead to the development of alternative proposals for risk reduction. The reason for the rather sparse use of this method in the chemical industry probably lies in the facts that former analyses were inadequately executed and that managerial staff regarded risk analysis as a method of locating uncertainties rather than a method for improving decision making. Provision of relevant aids for a comprehensive analytical method and a clear recognition of the inherent advantages should pave the way for wider acceptance of this procedure.
Absorption und Absorber
Authors: Mersmann Alfons , Hofer Helmut , Stichlmair Johann 
Published: May 2005

AbstractAbsorption and absorbers. In physical and chemical absorption, a gas is taken up in a liquid. Absorption methods are employed in particular in the production of synthesis gases and for the purification of gaseous effluents. The phase equilibrium is the essential deciding factor regarding the applicability of this method and its costing. A suitable absorber must be chosen, taking into account the properties of the gas and the liquid, and optimized for economic operation. Absorption processes and absorbers are briefly reviewed.
Untersuchungen zur Betriebscharakteristik pulsierter Füllkörperkolonnen für die Flüssig/Flüssig‐Extraktion
Authors: Bender Eberhard , Berger Rosemarie , Leuckel Wolfgang , Wolf Dieter 
Published: May 2005

AbstractStudies on the operating characteristics of pulsed packed‐columns for liquid/liquid extraction. The dependence of capacity limit and extraction efficiency on the operating conditions, the properties, and the packing material is illustrated with the aid of experiments on two test mixtures in pilot plant columns. The direction of mass transfer has a large influence on the capacity limit and extraction efficiency. From the practical point of view, the operating characteristics of pulsed packed‐columns provide the chemical engineer with reference data for the estimation of column dimensions and rational planning of pilot plant experiments. Methods for the precalculation of capacity limits and extraction efficiencies of pulsed packed‐columns are reported in the literature. A comparison of the results obtained by these methods with the experimental data indicates the feasibilities and limits of such a calculation.
Naßabscheidung von Feinstäuben und Aerosolen
Authors: Holzer Klaus 
Published: May 2005

AbstractWet separation of fine dusts and aerosols. Wet scrubbers are frequently employed in the chemical industry for the separation of fine dusts and aerosols from gas streams. In order to choose the most suitable apparatus for a given purpose from the numerous scrubbers available, 35 wet scrubbers of differing construction were examined on full and pilot‐scale regarding separating efficiency and operating behaviour. According to their flow conception, the scrubbers can be divided into five fundamental types, providing an almost automatic classification according to separating efficiency. The experimentally determined degrees of fractionation used as apparatus‐specific parameters are discussed and a relation between separation efficiency and specific power consumption is presented. The particular requirements of such apparatus in the chemical industry are outlined with the aid of some operational examples.
Nachbehandlung von Halbzeugen und Apparaten aus austenitischen Stählen zur Vermeidung von Spannungsrißkorrosion
Authors: Risch Karl 
Published: May 2005

AbstractAfter‐treatment of semifinished products and equipment made of austenitic steel to avoid stress corrosion. Among the factors initiating stress corrosion, the extent and distribution of internal tensile stress are the least tractable. Unknown internal stresses are always superposed on the estimable operational stresses. If they arise from distortions or welding, the former are distributed throughout the entire cross‐section. The action of tools, e.g. on turning or grinding, can also lead to high internal tensile stresses in a thin surface zone. Such stresses are of particular significance because stress corrosion is initiated on the surface. In this article, it is shown that it is usually sufficient to adequately reduce these surface‐proximate internal tensile stresses, e.g. by a pickling process removing a surface layer of material, in order to eliminate stress corrosion and thus to extend the scope of austenitic steels. Should the internal tensile stresses due to distortion and welding suffice to initiate stress corrosion under particularly aggressive conditions, one can attempt to reduce the stress by suitable heat treatment; however, no impermissable change in the microstructure of the steel may occur. Finally, it is also possible to produce compressive stress in a thin surface zone by shot peening so that no stress corrosion can take place. The advantages and disadvantages of the various possibilities are illustrated with the aid of examples.
Zum Stand des Schwingungsnachweises in Apparate‐ und Anlagenkomponenten
Authors: Klapp E.‐U. , Hartermann R.‐U. 
Published: May 2005

AbstractDetection of vibrations in equipment and plant components. A survey of recent experimental investigations in the field of flow‐induced vibrations is based on selected examples of cylindrical structures in transverse and axial flow. During recent years, great efforts have been undertaken in order to comply with stringent safety standards required especially for nuclear power plant. With regard to plant design and construction of plant assemblies, however, there is a lack of experimental work in which the main parameters were varied systematically. It is consesquently very difficult to develop semi‐empirical models for the calculations in this field. Another problem is that the behaviour of the structure is often investigated in isolation, i. e. without consideration of the influence of the whole plant on the structure of interest.
Diversifikation von Separatoren mit Düsen‐, selbstreinigenden und Vollmantel‐Trommeln
Authors: Hemfort Heinz 
Published: May 2005

AbstractDiversification of separators with nozzles, provision for selfcleaning, and solid bowls. The flow processes in most centrifuges, and thus also in disk separators, are still partly unknown. An empirical approach and experimentation are therefore of considerable importance for design and applications. Special designs are developed primarily for dealing with liquids having particular properties and the characteristics of various basic types are combined. Highly specialized machines usually result which are optimized for only very narrow fields of application. This development is illustrated for the combination of characteristics of separators having nozzles, provision for self‐cleaning, and solid bowls.
Kostenschätzungen mit Hilfe von Kostenstrukturanalysen
Authors: Burgert Werner 
Published: May 2005

AbstractCost estimation by cost structure analysis. During the various phases of a project, cost estimates for capital investments are necessary which satisfy the specific requirements at each stage, such as accuracy and degree of technical scope. A cost structure analysis enables satisfactory and accurate costing at an early stage with minimum cost. The evaluation of statistical data of numerous completed projects can provide an exact cost structure of different types of chemical plant. Examples of cost curves and their parameters for individual items of equipment are given and cost structures of various types of chemical plant are presented and discussed. Past experience in converting cost estimates based on German conditions into estimates that incorporate specific prevailing conditions at selected foreign sites is briefly mentioned.
Definition und Messung der Mischgüte in flüssigen Gemischen
Authors: Hiby Julius W. 
Published: May 2005

AbstractDefinition and measurement of quality of mixing in liquid mixtures.The relative deviation from homogeneity of a mixture can be defined in various ways. These expressions are adapted to the various methods of measuring the degree of mixing and the mixing time: probe methods; color change of chemical indicators; decoloration proportional to the conversion of a reaction; increase in temperature arising from heat of reaction. A comparative study of the various methods is presented (see also [1] in English language).
Fortschritte bei der Auslegung pneumatischer Förderanlagen
Authors: Bohnet Matthias 
Published: May 2005

AbstractAdvances in the design of pneumatic conveyors. Pneumatic conveyors can be constructed for a variety of flow conditions, such as, e. g. dilute phase conveying, strand conveying or plug‐flow conveying. The choice of the most favourable flow condition is naturally determined by the particular problem at hand, and, in particular by the physical data of the solid to be conveyed. In practice, when designing such conveyors, not only the processes taking place in the pipeline have to be taken into account but also those taking place during the feeding and separating of the solid, since these jointly influence the flow conditions of the whole system. The choice of fan is of considerable importance. The accuracy of the precalculation of pressure drops and the criteria for the choice of the most favourable gas velocity in the conveyor line are still unsatisfactory, in spite of the many previously confirmed findings. More recent investigations on the prediction of various flow conditions and on plug‐flow conveying enable a better choice of the most favourable method of conveying. Significant technical developments have been made, especially as regards calculated plug‐flow conveying.
Interkristalline Spannungsrißkorrosion an Hochtemperatur‐Winderhitzern. Werkstoffkundliche, fertigungs‐ und verfahrenstechnische Maßnahmen zur Minderung und Vermeidung der Schäden
Authors: Kalfa Horst , Bühler Hans‐Eugen 
Published: May 2005

AbstractIntercrystalline stress corrosion cracking (SCC) in high temperature hot blast stoves. After a brief survey of known cases of stress corrosion cracking and today's protective or repair measures, the results of lab tests are presented which provide new knowledge about the course of nitrate stress corrosion cracking. The lab tests are dynamic stress corrosion cracking tests allowing direct simulation of SCC‐attack on structural steels under operational conditions. It thus becomes possible to specifically intervene in the mechanism of SCC. Modifying the factors material, tensile stress, and medium provides a basis for the construction of hot blast stoves not sensitive to SCC.
Computergestützte Auswertung von Informationssammlungen in der Verfahrenstechnik
Authors: Kwiatkowski Josef , Blaß Eckhart 
Published: May 2005

AbstractComputer‐aided retrieval of data collections in chemical engineering. Data collections are an important tool for more efficient and economical engineering in the various fields of chemical process technology. The computer‐aided utilization of available data collections has major advantages compared with manual processing. Computer‐aided utilization can be based on the identification retrieval or rank retrieval method. The advantage of the rank retrieval method is that it provides a spectrum of solutions sorted by the degree of coincidence with the ideal solution. Rank retrieval can be integrated into larger program packages within an integrated computer system which supports the design of chemical plants.
Modelle und Berechnungsverfahren für die plötzliche Druckentlastung von Gas/Dampf‐Flüssigkeits‐Reaktionssystemen
Authors: Friedel Lutz , Purps Stefan 
Published: May 2005

AbstractModels and computational methods for the sudden release of pressure in gas/vapour‐liquid reaction systems. Design of pressure‐release sections in safety installations such as safety discs or safety valves for gas/vapour‐liquid reaction systems is essentially determined by thermodynamic and fluid dynamic processes as well as by the occurrence of parallel chemical reactions in the reaction vessels and in closed blow‐off lines. However, because of the highly complex interrelations and, in part, insufficient detailed knowledge, an exact calculation frequently causes difficulties. In order to present and evaluate the current state of the art, the individual phases of pressure release and the most important influencing factors as well as their significance for the pressure distribution as a function of time are described first. There follows a comparison of several computational methods taken from the literature, but which because they treat of the processes involved in a simple way either only permit very imprecise design of pressure‐release sections or which because of their specific model assumptions only apply to particular chemical reaction systems with special boundary conditions. Finally, the problems associated with the development of a generally applicable, reliable computational method are briefly discussed.
Temperieren mit Kreisstromwasser in chemischen Verfahrensanlagen
Authors: Schupmehl Leo , Schäfer Eugen 
Published: May 2005

AbstractTemperature control by recirculating water in chemical process plants. Temperature regulating systems that use water as circulating medium with direct feed of water vapour and cooling water are dynamically fast and favourable in price; therefore they are frequently installed. The designs produced show an according variety. First, the technical construction of such heating and cooling systems is described, concentrating on three different types – one circulation system for temperatures below 100 °C and two systems for higher temperatures with pressure regulation in circulating water by feed of additional water or by an appropriate steam bolster, respectively. Corresponding design factors such as heating and cooling capacity or pressure‐maintaining level and NPSH value are treated. It follows a description of the corresponding technical equipment for measurement and control. Depending on requirements, the different possibilities of instrumentation range from simple control to cascade control with limited regulation values and with P/PI‐structure changing during the start of process up to computer application. Even the selection of the regulation valves and the choice of valve characteristics are taken into consideration.
Auslegungskonzept für pulsierte Siebboden‐Extraktoren
Authors: Reissinger Karl‐Hermann , Marr Rolf 
Published: May 2005

AbstractA concept for the design of pulsed sieve‐plate extractors. A concept is presented for the design of pulsed sieve‐plate extractors (PSE) according to which the column diameter is calculated via the flooding load and the column length by concentration profiles using the well known backmixing models. This concept requires some parameters to describe the hydrodynamic and mass transfer behaviour. The parameters depend on physical properties, operating conditions, and extractor geometry and subject to mutual influence. It is now possible to present correlations and models for prediction of these parameters. The mass transfer term can be determined by Sherwood correlations for single drops, using the Sauter mean drop diameter. The total mass transfer coefficient can be given as a function of column lenght. The calculated concentration profiles agree well with the measured profiles and thus the concept is confirmed.
Die Beschreibung der Partikelabscheidung durch Trägheitskräfte mit Hilfe einer dimensionsanalytisch abgeleiteten Kennzahl
Authors: Bürkholz Armin 
Published: May 2005

AbstractDescription of particle precipitation by inertial forces by means of a group derived by dimensional analysis. The fractional degree of precipitation depends upon many operating parameters: these can be attributed to three independent dimensionless groups: the Stokes, the Reynolds, and the Euler number. On the basis of extensive experimental material, dimensional analysis shows that, for sufficiently large Reynolds numbers and in a large range of the Euler number, the inertial precipitation depends upon a single dimensionless group, the precipitation parameter ΨA. It can be regarded as the ratio of two energies, viz. a characteristic precipitation energy, expressed as the product of the inertial energy of the particle and the pressure drop coefficient of the precipitators, and a frictional energy dissipated in the boundary surface of the impact body. Thus inertial precipitation is transformed from a complicated flow problem into an energetic problem in which pressure drop plays a major role. Simple approximation formulae can be given for the fractional degree of precipitation and the limiting droplet size for all types of separators.
Teilchengrößen‐Bestimmung mittels dynamischer Lichtstreuung
Authors: Wagner Joachim 
Published: May 2005

AbstractParticle‐sizing by dynamic light scattering. The range of applications of colloidal systems is often defined merely by their particle‐size distribution. Dynamic light scattering has proven to be a fast and precise technique for sizing particles in the range of 3 nm to 3 μm. This paper describes the basis of measurement and the method of data analysis. Numerous applications of dynamic light scattering in the chemical industry are also given.
Aerosolbildung in Absorptionsprozessen – Ursachen und Lösungsansätze
Authors: Ulbrich Michael , Sachweh Bernd , Meckl Stefan , Schraut Armin , Hölemann Karl 
Published: May 2005

AbstractAerosol Formation During Absorption Processes ‐ Causes and Solution Strategies.If a gas phase contains inerts or components with a wide range of volatility then supercooling may occur during an absorption or partial condensation process. The resulting supersaturation can lead to aerosol formation in the presence of condensation nuclei. During the production and processing of chemical products aerosol formation can lean, for instance, to corrosion, non‐fulfilment of specifications, or catalyst poisoning. Aerosol separators often represent a costly problem solution because they consume energy and require additional investment, whereas the avoidance of aerosol formation, if possible, represents a cost‐favourable alternative. In this article, the causes of aerosol formation are analysed and four strategies for solving the problem of aerosol formation are developed. Industrial aerosol problems are considered to illustrate how these strategies can be implemented in practice.
Praxisrelevante Simulationswerkzeuge für mehrstufige Batch‐Prozesse
Authors: Daun Gregor , Bartenbach Bernd , Battrum Mike 
Published: May 2005

AbstractPractically Relevant Simulation Tools for Multistep Batch Processes During the development and improvement of multistep batch processes, the description and optimum design of the material and temporal link‐up of the various units for reaction, isolation, and solvent work‐up is becoming increasingly demanding and requires software support. Distinguishing criteria are first derived for the various simulation tools and these are then supplemented with specific industrial demands placed on simulation tools for overall processes. The authors then provide an overview of commercially available programs above all for simulation of overall processes and report on their own experience. The potential of tools for simulation of overall processes lies not in the reduction of the number of experiments but in better utilisation of plant capacity by improved batch planning, in centralised data storage, in a largely standardised, simplified and consistent documentation, and hence simplified communication.