bluuebunny/crossref_metadata_2025_split huggingface dataset:
Process design with energy and environmental constraints
Authors: Timmerhaus Klaus D. , Reusch Charles F. 
Published: May 2005

AbstractIt is evident that the philosophy of process design has changed dramatically with the advent of higher energy prices and stricter environmental regulations. It is only with careful design and well‐practiced operation that maximum recovery of energy in the form of steam, electricity and refrigeration can be successfully achieved. Initial capital costs will generally be higher, but operating costs are lower, particularly in this era of high fuel costs. The major problems that are usually associated with these „tighter”︁ designs are more difficult maintenance and more complex startup problems. The latter are due to the energy integration which is built into an energy efficient plant. On the other hand, maximizing energy recovery and increasing yields of feedstocks not only lowers operating costs but often can have environmental advantages because exhaust gases and liquids are either consumed in the plant or contaminants are recovered as byproducts.
Verfahren zum Trennen von dispersen Feststoffgemengen in ihre stofflichen Komponenten
Authors: Kellerwessel Hans 
Published: May 2005

AbstractVerfahren zum Trennen von dispersen Feststoffgemengen nach stofflichen Eigenschaften – Sortierverfahren – erlangen zunehmend Bedeutung auch außerhalb ihrer klassischen Anwendungsgebiete, nämlich der Aufbereitung mineralischer Rohstoffe und landwirtschaftlicher Produkte. Dies gab Veranlassung zu einer Zusammenstellung, in der die Grundlagen der wichtigsten Sortierverfahren und ihre Anwendungsmöglichkeiten außerhalb der klassischen Bereiche aufgezeigt werden.
Längsmischung in gerührten Gegenstrom‐Extraktoren
Authors: Marr Rolf , Moser Franz , Husung Gerrit 
Published: May 2005

AbstractEs wurden die Methoden zur Erfassung der Längsmischung in gerührten Extraktoren behandelt. Dabei ergab sich, daß lediglich die einphasigen Vermischungszustände der kontinuierlichen Phase gut bestimmbar sind; mit gewissen Einschränkungen gilt das auch für die disperse Phase. Vor allem für RDC und ARD liegen Korrelationen vor, die die Berechnung von Bodenstein‐Zahlen der kontinuierlichen Phase bis zu 4 m Kolonnen‐Dmr. zulassen. Beim Kühni‐Extraktor dagegen ist von derartigen Hochrechnungen bei Maßstabsvergrößerungen noch abzuraten. Es wird ein Weg zur Ermittlung rückvermischungsfreier HTU‐Werte erläutert, der die Übertragung auf Großkolonnen erlaubt. Es ist daher von großer Bedeutung, ausreichend gute Korrelationen zur Berechnung der Vermischung der dispersen Phase zu finden, um im Zusammenhang mit denen der kontinuierlichen Phase möglichst exakte Dispersionshöhen zu erhalten. Diese sind von der Geometrie und den Betriebsvariablen abhängig und sollten daher auch bei großen Kolonnen bestimmt werden. Damit wäre eine gute Möglichkeit gegeben, Kolonnenhöhen nach diesem Konzept zu berechnen.
Blasensäulen‐Reaktoren – ihre modellmäßige Erfassung und Berechnung
Authors: Deckwer Wolf‐Dieter 
Published: May 2005

AbstractDie Dimensionierung und Maßstabsvergößerung von Blasensäulen‐Reaktoren ist trotz ihrer einfachen Bauweise eine recht schwierige Aufgabe. Es sind im wesentlichen zwei Punkte, die die „a priori”︁ ‐Berechnung erschweren und die nicht unabhängig voneinander betrachtet werden dürfen. Der 1. Punkt betrifft die Besorgung von Parameterwerten, der 2. Punkt liegt in der Auswahl realistischer Modelle. Aus dem Verweilzeitverhalten der Phasen ergibt sich, daß Modelle für Blasensäulen auf der Basis des Dispersionsmodells bzw. dazu äquivalenter Zellenmodelle zu erstellen sind. Zusätzlich liegt ein Druckgradient vor. Wenn deutliche Molstromänderungen in der Gasphase auftreten, wie es für die Praxis wünschenswert ist, ist ferner zu berücksichtigen, daß die Gasgeschwindigkeit und die relativen Phasenanteile variabel sind. Diese Modellannahmen führen auf ein nichtlineares Differentialgleichungssystem mit Randwerten, das nach verschiedenen Methoden numerisch gelöst werden kann. Aus Modellsimulationen wird der Einfluß der verschiedenen Parameter und Betriebsbedingungen ersichtlich. Experimentelle Untersuchungen zur mit Schwefelsäure katalysierten Hydratation von Isobuten und zum Stoffaustausch von CO2 in Blasensäulen bis zu 7 m Höhe bestätigen die Modellvorstellungen. Die experimentellen und theoretischen Ergebnisse werden mit Aussagen einfacherer Modelle verglichen und die Bedingungen angegeben, bei denen ihre Anwendung zu rechtfertigen ist.
Ultrafiltration und Umkehrosmose Grundlagen und Technologie
Authors: Rautenbach Robert , Rauch Klaus 
Published: May 2005

AbstractZur Beschreibung des Stofftransportes in technischen Membranen sind mehrere Modellvorstellungen entwickelt worden. Ausgehend von einer Diskussion dieser Vorstellungen wird gezeigt, wie Anlagen für Membrantrennprozesse ausgelegt werden können. Die Arbeit beschränkt sich dabei auf die technisch z. Z. meist diskutierten Membrantrennverfahren „Ultrafiltration”︁ und „Umkehrosmose”︁, bei denen die Abtrennung einer Komponente aus einer meist wäßrigen Lösung aufgrund einer transmembranen Druckdifferenz erfolgt. Für die Auslegung ist neben dem Transport in der Membran selbst der Stofftransport aus der zu trennenden Lösung an die Membranoberfläche von Bedeutung. Es wird gezeigt, daß zur Beschreibung dieser Vorgänge bekannte Gleichungen für den Wärmetransport herangezogen werden können, daß aber im Gegensatz zu einer Wärmeaustauscher‐Berechnung das Gleichungssystem zur Berechnung der Flüsse und Konzentrationen an angeströmten Membranen nur iterativ gelöst werden kann. Die wichtigsten Membrankonfigurationen (Rohr‐, Platten‐, Hohlfaser‐ und Wickelmodul) werden besprochen und Gleichungen zur Beschreibung ihrer Austauschcharakteristik angegeben.
Kostenvorausberechnung von Apparaten und Anlagen — Möglichkeiten und Grenzen
Authors: Schwind Hermann 
Published: May 2005

AbstractCosting of equipment and plants – possibilities and limitations. The costing of individual items of equipment and of complete plants differs considerably with respect to design as well as to the accuracy and time‐requirement of the calculation method. These calculations are included in the usual way in economic evaluations of plants in order to assess the overall profit situation of a plant project. Numerous publications on this subject have appeared in recent years. They are evaluated in this report with reference to the abovementioned aspects. Besides the cost‐precalculation methods used in project engineering, a few systematic costing methods are proposed for the planning‐, erecting‐ and operating‐period of a plant. This facet of the subject is also critically examined.
Blasensäulen‐Reaktoren
Authors: Gerstenberg Helmut 
Published: May 2005

AbstractBubble column reactors.Bubble columns and their state of development have been reviewed on numerous occasions in recent years. As an extension, this paper deals with bubble column reactors from an industrial point of view. The numerous forms of construction and modes of operation in industry can be reduced to relatively few fundamental types. Since the computerized design of bubble columns is presently restricted to a few partial processes, experience in the choice of a particular type column still plays an important role. The article deals, inter alia, with reactors (gas distribution, gas‐ and liquid‐feeds, gas separation, heat extraction), selection criteria for construction and for operating conditions, practical experience, and some specific forms of operation. Some problems still requiring scientific investigation are outlined.
PROBAD – Programmsystem zur Festigkeitsberechnung von Behältern, Apparaten und Dampf‐Erzeugern
Authors: Schmidt‐Traub Henner 
Published: May 2005

AbstractPROBAD – A program system for stress calculations on vessels, equipment, and steam generators. The PROBAD program system performs stress calculations according to TRD Rules, AD Codes, DIN Standards, as well as ASME Code Sec. VIII Div. 1 and TEMA Standards. Starting from given assemblies, whole vessels or parts thereof are designed or checked. Moreover, the PROBAD language also permits supplementary assignment of user‐specific and standard values to the system without any need for direct modification of the program system. The input and output can likewise be set up in a user‐specific manner.
Titancarbid – Ein technischer Hartstoff
Authors: Binder Franz 
Published: May 2005

AbstractTitanium carbide – an industrial hard material. Titanium carbide, whose industrial application has been closely linked with the history and development of sintered metal carbides since 1930/31, has revolutionized the technology of the machining of steel when used in the form of multicarbide composites. Typical innovations of the post‐war era are not only the dominant WC/TaC/TiC‐Co carbide materials but also TiC‐NiMo materials and TiC‐coated metal cutting devices. In contrast to TaC or WC, the market situation is largely independent of price and quantity fluctuations of raw materials.
Zusätzliche Sicherheitsaspekte des Mehrlagenbehälters
Authors: Opitz K. , Beser A. E. 
Published: May 2005

AbstractAdditional safety aspects of coiled‐layer containers. The coiled‐layer construction technique has a number of particular safety engineering advantages over solid construction methods which are characterized by the following features: (1) Each kind of stress in a container is directed to a shell specially designed for this kind of stress. (2) A planned arrangement of welding seams minimises weakening. (3) The containers can be constantly monitored. (4) Failures remain under control owing to the possibility of constant monitoring. Examples and experiments are reported for the Krupp coiled‐layer construction method.
Automatisierte Überwachung der Luftverschmutzung
Authors: Mögele Ludwig , Birkle Michael 
Published: May 2005

AbstractAutomated monitoring of atmospheric pollution. More and more fully‐automated, computer‐controlled measuring grids for the monitoring of immission or nuisance levels are being planned and implemented. The requirements and limiting conditions in immission surveillance lead to hierarchically organized measuring systems in which the analytical apparatus are combined in automated monitoring stations. The monitoring stations each contain apparatus for the various pollutants as well as ancillary equipment. Great importance is attached to the sampling system and to equipment for automatic instrument surveillance.
Technische Prototypen für die Altreifen‐und Kunststoff‐Pyrolyse
Authors: Kaminsky Walter , Sinn Hansjörg , Janning Jörg 
Published: May 2005

AbstractIndustrial prototypes for the pyrolysis of used tyres and waste plastic materials. The increasing amounts of old tyres and waste plastics are creating problems regarding their disposal and recycling. Such wastes, however, can be converted by pyrolysis into almost residue‐free organic raw materials. Various processes, particularly for the pyrolysis of old tyres, are described which have been tested in Japan, the USA, Great Britain and the Federal Republic of Germany. In indirectly heated fluidized sand beds whole automobile tyres can be decomposed to give up to 20 wt‐% gas, 30 wt‐% aromatics, 40 wt‐% carbon black, and 10 wt‐% steel scrap.
Zum Stand der Berechnung von Behälterabstützungen und Fußkonstruktionen
Authors: Depmeier Lüder , Lambrecht Diethelm 
Published: May 2005

AbstractCalculation of vessel supports and foot constructions. Supports of vessels often cause large strains in the wall of the container; generally the calculation of the resulting deformations and stresses turns out to be difficult. Several types of construction and the problems associated with local loadings are described, and possible methods of calculation are listed. Generally known publications are compared. Methods of series expansion are considered in more detail and their advantages as well as their limitations are shown for the example of a Fourier series expansion for a cylindrical tank. In addition two examples are considered which permit comparisons between our own calculations and usual methods and experimental results, respectively.
Energiewirtschaftliche Rationalisierung bei der Projektierung von Chemieanlagen
Authors: Schulze Joachim 
Published: May 2005

AbstractReduction of energy costs in planning of chemical plant. Energy consumption in the chemical industry is especially high, and on inclusion of energy sources used as raw materials the energy consumption figures are even doubled. The most important energy consumption data are presented. The economic incentives for the reduction of energy costs have increased with energy price hikes, and project engineering of new chemical plants offers an extensive field for energy saving measures. An account of the basic methods of economic optimisation of chemical plant equipment, with particular regard to the reduction of energy consumption, is followed by a systematic review of the various sectors of chemical plant design in which energy saving measures can be applied.
Entwicklungstendenzen bei Einschneckenextrudern
Authors: Fritz Hans‐Gerhard 
Published: May 2005

AbstractDevelopments in single worm extruders. Starting from the multifarious chemical engineering tasks to be mastered in production and processing of plastics, the single worm extruders nowadays used for this task (plastifying extruders, melt‐exit extruders, degassing extruders, and cascade systems) are presented and the associated foci of development are mentioned. It becomes clear that further reductions in the price/performance relation of such plant will most likely be accomplished by a systematic analytical description of the mechanical/thermal unit process of conveying of solids in the individual functional zones, of plastifying, mixing, and homogenization, and pressure build‐up. The knowledge accruing from such model considerations leads to extruder sections which are optimized energetically and engineeringwise (grooved entry, intensive heat‐up, exit zones) which in turn satisfy requirements for higher mass throughputs and improved product quality. Similar analyses of the extruder/tool combined system can serve as a basis for process models for fully automated operation of extruders by means of microcomputer systems so far used to control individual operating parameters and acquisition of operating data.
Zur Maßstabsübertragung beim Suspendieren im Rührgefäß
Authors: Kneule Friedrich 
Published: May 2005

AbstractScale‐up of agitated vessels in the case of suspensions. In the scale‐up of agitated vessels a decrease of specific power input ε is recommended in the case of suspensions. Up to now it has been assumed that turbulence is the reason for this decrease. This paper shows that there may also be a contribution due to decreasing wall areas causing less wall shear stresses and moreover a reduction of circulation due to lower cross‐sectional areas per unit volume of the threads of flow. In the case of so‐called „complete suspension”︁ according to the „1‐s criterion”︁, two mechanisms can be distinguished: On the one hand we have a lifting of solid particles without, and on the other hand such a lifting with formation of bulk accumulations of solids on the bottom of the vessel. In the first case, scale‐up can be done as for a homogeneous distribution of the solid material. The specific power input ε is ∼ μ0 up to ε ∼ μ−1 with the scale‐up factor μ. In the second case (formation of dense solids clouds) a relationship ε ∼ μm with m > 0 was found.
Umweltfreundlichere Produktionsverfahren in der chemischen Industrie
Authors: Swodenk Wolfgang 
Published: May 2005

AbstractEnvironmentally more acceptable processes in the chemical industrys. From its very beginning the chemical industry has always made every effort to cut the consumption of raw materials and energy in its processes and to diminish the release of by‐products and waste streams into the environment. These efforts at technically improving the various processes are presently being intensified by economical and political pressures of rising raw material costs and the rising costs of releasing harmful substances into the environment. Ways of reducing these influences on the environment by chemical processes and of improving process economics will be reported from the experience of Bayer AG. The examples show that it is possible to combine the indispensable with the practicable, and that in this way the burden on the environment can be kept as low as may be consistent with the image of the industrial society.
Investitionskosten‐Schätzung für Chemieanlagen
Authors: Prinzing Peter , Rödl Roland , Aichert Dieter 
Published: May 2005

AbstractCapital cost estimation for chemical plant. During the preliminary stages of an investment project (before approval), several decisions have to be made on whether or not it should be pursued. Therefore cost estimates are required with stepwise reduction in uncertainty. However, the attainable accuracy of a cost estimate is a function of progress in engineering the entire project. Thus, each step in cost estimation entails a higher degree of planning and demands methods that satisfy the accuracy demanded and correspond to the progress made in engineering. A comprehensive estimation system has been developed from these interrelations, and the respective procedures are described. This paper considers known fundamentals and the authors' own developments.
Der Wärmetransformator – Grundlagen und Anwendungen
Authors: Stephan Karl 
Published: May 2005

AbstractHeat transformers – principles and applications. Heat transformers can transform low temperature waste heat into useful heat of higher temperature. They work by a sorption process and require little mechanical energy. This paper reviews the fundamentals, development trends, possible applications, and reports the efficiencies that can be expected when using different working substances. The economy of the process depends strongly on the credit for the useful heat. Some heat transformers are already in operation and deliver useful heat in the range of 1 to 10 MW.
Vakuumpumpen in der Verfahrenstechnik
Authors: Teifke Jürgen , Bohnet Matthias 
Published: May 2005

AbstractVacuum pumps in chemical engineering. Applications of vacuum pumps in chemical engineering are numerous. After a general systematization of the working principles of vacuum pumps, the most important types – liquid ring vacuum pumps, sliding vane vacuum pumps, and ejectors – are discussed with regard to their development and their working principle. Attention is focussed on aspects which allow a comparison of the advantages and disadvantages of vacuum pumps. A systematic survey of the criteria leading to the selection of a certain type of pump show that these criteria may be based on the process as a whole or on environmental and safety considerations as well as economic aspects. In areas where liquid ring vacuum pumps, sliding vane vacuum pumps, and ejectors may be applied the extent to which the pumps fulfill these criteria is shown. In this context, a comparison of the liquid ring pump and the sliding vane pump is of special interest. The doubts recently publicized concerning the environmental compatibility of liquid ring vacuum pumps are shown to be groundless if the pumps are installed correctly. Great care must be taken comparing the economic aspects of liquid ring pumps and sliding vane pumps.
Elektromembranverfahren. Teil 2: Anwendungsbeispiele
Authors: Kuppinger Franz‐Felix , Neubrand Wolfgang , Rapp Hans‐Jürgen , Eigenberger Gerhart 
Published: May 2005

AbstractElectromembrane Processes, Part 2: Applications. The first part of this survey described the fundamentals and the basic equations for the mathematical modelling of electromembrane processes. In the second part a number of applications is considered. First mass transfer in ion exchange membranes is discussed. Further points are electrodialysis with bipolar membranes for the production of acid and base from a salt solution and some recent developments for the combination of electrodialysis and ion exchange.Electrodialyse with bipolar membranes allows the recycling of acids or bases from acid or base scrubbersand can also be used for electrochemical reactions in nonaqueous media. Combination of electrodialysis and ion exchange permits a continous operation of ion exchange columns with simultaneous regeneration using ion exchange membranes. This results in low consumption of regeneration chemicals and the minimisation of waste products.
Hydrodynamischer Ansatz zur Modellierung von Fällungen
Authors: Franke Dirk , Gösele Walter 
Published: May 2005

AbstractModeling Precipitation with a Hydrodynamic Approach Particle sizes produced by precipitation are of prime importance for subsequent process steps, and they depend on mechanisms hardly understood until now. In this paper a new approach to the understanding of particle formation by precipitation is given. The solid is formed in the microscopic „Kolmogorov vortices”︁ where molecular mixing occurs. Loose aggregates within the vortex are cemented together by newly formed solid, the maximal size of the resulting solid aggregates being limited by the size of the vortex. Numerical calculation of the number of aggregates within the vortices and of the resulting aggregate sizes is performed, using one constant arbitrary fitting parameter. The agreement with experimental results is good. Further improvements of the model will require a better description of local fluid dynamics („mesomixing”︁).
Nitric oxide/cyclic guanosine monophosphate signaling in the central complex of the grasshopper brain inhibits singing behavior
Authors: Wenzel Beate , Kunst Michael , Günther Cornelia , Ganter Geoffrey K. , Lakes‐Harlan Reinhard , Elsner Norbert , Heinrich Ralf 
Published: May 2005

AbstractGrasshopper sound production, in the context of mate finding, courtship, and rivalry, is controlled by the central body complex in the protocerebrum. Stimulation of muscarinic acetylcholine receptors in the central complex has been demonstrated to stimulate specific singing in various grasshoppers including the species Chorthippus biguttulus. Sound production elicited by stimulation of muscarinic acetylcholine receptors in the central complex is inhibited by co‐applications of various drugs activating the nitric oxide/cyclic guanosine monophosphate (cGMP) signaling pathway. The nitric oxide‐donor sodium nitroprusside caused a reversible suppression of muscarine‐stimulated sound production that could be blocked by 1H‐[1,2,4]oxadiazolo‐[4,3‐a]quinoxaline‐1‐one (ODQ), which prevents the formation of cGMP by specifically inhibiting soluble guanylyl cyclase. Furthermore, injections of both the membrane‐permeable cGMP analog 8‐Br‐cGMP and the specific inhibitor of the cGMP‐degrading phosphodiesterase Zaprinast reversibly inhibited singing. To identify putative sources of nitric oxide, brains of Ch. biguttulus were subjected to both nitric oxide synthase immunocytochemistry and NADPH‐diaphorase staining. Among other areas known to express nitric oxide synthase, both procedures consistently labeled peripheral layers in the upper division of the central body complex, suggesting that neurons supplying this neuropil contain nitric oxide synthase and may generate nitric oxide upon activation. Exposure of dissected brains to nitric oxide and 3‐(5′hydroxymethyl‐2′‐furyl)‐1‐benzyl indazole (YC‐1) induced cGMP‐associated immunoreactivity in both the upper and lower division. Therefore, both the morphological and pharmacological data presented in this study strongly suggest a contribution of the nitric oxide/cGMP signaling pathway to the central control of grasshopper sound production. J. Comp. Neurol. 488:129–139, 2005. © 2005 Wiley‐Liss, Inc.