bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dichtstromförderung
Authors: Krambrock Wolfgang 
Published: December 2004

AbstractHigh density pneumatic conveying. In distinguishing between high density pneumatic conveying and low density conveying it is insufficient to merely use the solids loading to characterize the various flow states. Less ambiguous classification is possible only on the basis of the diagram of state of pneumatic conveying. Most flowable bulk solids can be transported through normal smooth‐walled piping in the high density mode with normal conveying equipment. In contrast, fine‐grained products in particular tend to adhere to the wall and form blockages. Paying due attention to the differing flow properties of various bulk solids and to the mechanisms of blockage formation and clearance, various new conveying techniques and piping types have been developed in recent years, permitting in some cases the transport of adhering, abrasive, and attrition‐sensitive materials. Since conveying pressures up to about 6 bar are usual in the high‐density regime, various combinations of pressure vessels are primarily used for feeding the bulk solids into the conveying pipes. The advantages of conventional, and also special high‐density conveying systems are discussed with the aid of examples.
Hydrierende Vergasung von Kohle – Neuere Betriebsergebnisse
Authors: Fladerer Rolf , Schrader Lothar 
Published: December 2004

AbstractHydrogasification of coal – recent operational results. The Rheinische Braunkohlenwerke AG has built and has been operating a semi‐technical pilot plant for hydrogasification of coal in a fluidized bed. The objective is to develop a coal gasification process with hydrogen for producing directly substitute natural gas. Between 1976 and 1981, the semitechnical pilot plant having a capacity of 100 kg C/h was operated for about 22,900 h under test conditions, more than 9,500 h of which were under gasification conditions. During this time, approximately 1,400 metric tons of dry coal were gasified. The longest coherent operational phase under gasification conditions was 748 h in which 86.4 metric tons of dry lignite were gasified. Carbon gasification rates up to 82% and methane contents in the dry raw gas (free of N2) up to 48 vol.‐% were obtained. A detailed evaluation of the test results provided information on the influence of additional parameters on the efficiency dates of the gasifier and a considerable refining of the results obtained previously. Moreover, several components were tested for which no operational experience had previously been gained; these were newly developed devices, e. g. the inclined tube for feeding coal into the fluidized bed. Within the framework of scale‐up work to large‐scale coal gasification plants, a pilot plant having a capacity of approximately 6 t C/h will be commissioned in late 1982.
Mechanismus der katalysierten Synthese von Kohlenwasserstoffen
Authors: Sachtler Wolfgang M. H. 
Published: December 2004

AbstractOn the mechanism of the catalysed synthesis of hydrocarbons. Recent results by independent research teams prove that, in hydrocarbon synthesis over metal catalysts in a reducing atmosphere, the dissociative adsorption of CO is of considerable importance. On the catalyst surface the two fragments, Cads and Oads, react swiftly with hydrogen to CHx,ads and H2O respectively. CHx,ads can be either hydrogenated to methane or incorporated in growing chains. This process may be visualized as a cis insertion of a carbene CH2,ads in a metal‐alkyl bond. In the steady state the catalyst surface is predominantly covered with COads, only a small fraction of the surface atoms carrying growing alkyl groups. These have been detected by 13C labelling as well as by IR spectroscopy.
Verfahrenstechnik der aeroben Abwasserreinigung. Entwicklungen und Trends
Authors: Zlokarnik Marko 
Published: December 2004

AbstractChemical engineering of aerobic waste water treatment – developments and trends. The present article deals with chemical engineering problems encountered in biological waste water treatment, as seen in research reports published during the last 5 to 10 years. It is seen that important advances in our biological and engineering knowledge of the biological degradation of organic wastes, relating to residence time distribution, concentration of biomass, and the temperature in the activation process have not been given sufficiently consistent attention in practice. Controversial views and possible solutions are indicated. Immobilization (especially with activated charcoal as carrier) offers certain advantages for raising the concentration of biomass in the activation space, this also facilitating separation of the biomass from the purified water. Flotation could offer an alternative. Disposal of the excess activated sludge is nowadays accomplished largely by anaerobic fermentation (bioconversion); the engineering of this step was developed in the 1930's and should be updated at the earliest possible opportunity. This would enhance the appeal of the process because the energetic potential of the biomass could then be fully utilized.
Neuere Entwicklungen bei Härtbaren Formmassen. Werkstoffe – Anwendungen – Verarbeitungs‐Technologien
Authors: Jellinek Karl , Schöunthaler Waldemar , Niemann Klaus 
Published: December 2004

AbstractNew developments in thermosetting moulding compounds – Materials – Applications – Processing technology. Thermosetting moulding compounds are defined as raw materials manufacturing plastic parts under the influence of pressure and heat, mainly by compression, transfer and injection moulding which are formulated in workable form from thermosetting reactive resins, fillers, reinforcers, and other additives. The present article will consider only moulding compounds in granular form whose processing to moulded parts is mainly automated and which represent a group of plastics clearly distinct from pasty or liquid thermosetting moulding materials.
Entwicklungen in der Technologie zur Herstellung von Brennstoffen aus kommunalen Abfällen
Authors: Kaster Bernhard 
Published: December 2004

AbstractDevelopments in the technology of fuel production from municipal waste. Various methods have been developed in recent years for the production of fuel from municipal waste in the USA and in Europe, and some of them have been tested on a large scale. They utilize mainly machines employed in mechanical work‐up and proven process steps developed specifically for the recovery of materials from municipal waste. Starting from the demands placed on the fuels the present status in Europe and the Federal Republic of Germany is illustrated with the aid of selected examples. The paper reports experimental results, operating experience, measures adopted to optimize the process engineering and to improve the fuel quality. It is not yet possible on the basis of the results obtained so far to estimate whether the production of fuels from waste will become accepted practice in Germany. It will be decisive whether the quality of the fuel can be optimized such that the limiting pollutant levels can be met without any need for flue gas scrubbing and whether longterm economic marketing of the fuel products is feasible.
Aufgaben des Werksarztes in der chemischen Industrie
Authors: Thiess Alfred M. 
Published: December 2004

AbstractTasks of the company doctor in the chemical industry. The tasks of the company doctor are stipulated in paragraph 3 of the works doctor, safety engineers, and other specialist staff for works safety act (ASIG) of December 12, 1973. However, long before this act was passed, responsible companies, especially in the heavy chemical industry, employed factory doctors. In the present industrial and technical age, the health care of employes is of prime importance in a modern company; health care is not merely demanded by social ethics but remains a responsible managerial task. The activities of the company doctor extend far beyond the requirements specified in the above act (ASIG) and also include preventative medicine. The participation of company doctors in national and international occupational medicine committees, e. g. in company inspectorate, professional organizations, ministry of employment, federation of the chemical industry, working committee, CEFIC, EC, WHO, etc.
Trennen von Gasgemischen durch Adsorption
Authors: Mersmann Alfons , Münstermann Ullrich , Schadl Josef 
Published: December 2004

AbstractSeparation of gas mixtures by adsorption. Gas mixtures are separated primarily by absorption and rectification. Rectification requires at least (v + 1)‐fold of the enthalpy of the distillate as heat energy (v is the reflux ratio). In the case of absorption, the resulting solution is frequently subjected to thermal regeneration with the energy requirement depending inter alia on the boiling point of the solvent. In view of the high energy requirements of these processes and the development of new adsorbents, possibilities of separating by adsorption with subsequent regeneration of the adsorbents, above all by change in pressure, are investigated. The separation of gas mixtures in adsorber beds (e.g. molecular sieves, silica gel, activated charcoal and coke, or alumina) depend upon various separating effects: steric effects, equilibrium effects, kinetic effects. A survey is given of proposed and practical industrial separation processes utilizing adsorption.
Ethanol als Rohstoff für die chemische Industrie
Authors: Swodenk Wolfgang 
Published: December 2004

AbstractEthyl alcohol as raw material for the chemical industry. The oil crisis has awakened consciousness of the forseeable end of oil supplies and evoked an intensified search for alternative sources of raw materials. Aside from coal, naturally growing raw materials are attracting renewed attention. Ethanol is frequently discussed as a potential key product for further chemical use. For a realistic assessment of the potential of ethanol as a chemical raw material, model cases are considered in which the availability of the naturally growing raw materials for ethanol, the necessary investments for its production and further use, and the financial competitiveness of ethanol are investigated as main criteria.
Das mechanische Entfeuchten von Filterkuchen
Authors: Redeker Detmar , Steiner Karl‐Heinz , Esser Ulrich 
Published: December 2004

AbstractMechanical demoisturing of filter cakes. Flow and centrifugal demoisturing and pressing are the principal methods of mechanical demoisturing of filter cakes. In flow demoisturing cracking has a detrimental effect. Compressibility, flow and centrifugal demoisturing can be completely described mathematically in dimensionless form. The limitations of mechanical demoisturing are presented for individual examples of apparatus.
Neue apparative Entwicklungen bei Filterzentrifugen
Authors: Hultsch Günther 
Published: December 2004

AbstractNew equipment developments in filter centrifuges. Industrial filter centrifuges are used for solid throughputs from ca. 0.01 to 250 t/h per machine. The specific filtration resistance of the solids to be separated likewise covers a range of ca. 1 :25 000. In addition to the enormous range of physical properties and mass flows, a wide variety of demands is placed on the chemical resistance of the materials of construction and the safety of the plant. These demands led to the development of a wide range of filter centrifuges, the most important types of which are first surveyed from a chemical engineering standpoint. There follows an account of the principal characteristics of recent types and the development of various details.
Probleme bei der Filtration unter extremen Gas‐ und Staubbedingungen
Authors: Schulz Reinhard 
Published: December 2004

AbstractFiltration problems under extreme conditions. Filtering separators belong to the high‐performance separators and their significance in dust extraction techniques is increasing. They are distinguished by offering almost any desired efficiency of separation which property, on use of appropriate filter media, is also preserved under fluctuating working conditions with regard to dust content in the crude gas, size of the dust particles to be separated, and the rate of gas flow. In order to exploit these advantages also under extreme conditions of gas and dust attempts were made in recent years to extend the operating range by the development of new filter media. Among the applications deserving mention are the fly‐ash collection in coal‐fired power plants and the dust separation under high temperatures for new power technologies. The present state of the art and experience gained so far are presented.
Entwicklungen zur Flugstrom‐Vergasung nach dem Koppers‐Totzek‐ und dem Prenflo‐Verfahren
Authors: Schmidt‐Traub Henner , Pohl Hans Christoph 
Published: December 2004

AbstractDevelopments on entrained‐flow gasification using the Koppers‐Totzek and the Prenflo process. Many years of operating experience have permitted continuous improvements in capacity and availability of entrained‐flow gasification plant applying the Koppers‐Totzek process. Further increases in capacity and economy, in particular where poorly reactive coals are to be gasified, will be achieved using the pressurized Prenflo process. Gasifier development is being supplemented by the development of complementary equipment, such as dry coal‐dust feed, material flow metering, and process automation. Closed wash water systems and other processing stages serve to improve environmental protection. The combination of pressurized gasification with a power station permits economical power generation with a high degree of efficiency and minimal environmental impact. Individual problems connected with pressurized gasification are being researched in a 48 t/d pilot plant.
Reaktionstechnische Grundlagen zur Auslegung und zum Betrieb von Bioreaktoren, Teil 2
Authors: Schügerl Karl 
Published: December 2004

AbstractReaction engineering fundamentals relating to design and operation of bioreactors, Part 2. Part 1 of this contribution treated balances, thermodynamic data and models. The present part 2 considers the following: dynamic behaviour of combined reactor models, reactor observability and controllability, process design (optimum performance), optimal feed‐back control, and the feasibility of these points. In the case of biological systems the present limits of measured data acquisition have been reached. New measuring instruments will have to provide more information about the cells and about the dynamic behaviour of the cell‐reactor system.
Umweltschutz bei der großtechnischen Kohlenutzung
Authors: Allhorn H. , Huber W. , Birnbaum U. 
Published: December 2004

AbstractEnvironmental protection at industrial scale utilization of coal. In view of the expected increase in consumption of coal and coal products to satisfy energy demands, a consideration of emissions released from coal mining and utilization facilities is of particular interest. Starting from a discussion of basic technical principles, possible sources of emission are established for the most important processes with electricity generation and coal refining playing major roles. A study of possible measures to reduce emissions, as well as emission data available in the literature, indicate future alternative courses of action when adopting various methods of utilization.
Verfahren zur Herstellung von Solarsilicium
Authors: Aulich Hubert Alfred , Schulze Friedrich‐Wilhelm , Grabmaier Josef Gabriel 
Published: December 2004

AbstractProduction of solar silicon. Economic exploitation of solar energy using solar cells made of crystalline silicon is dependent upon a considerable drop in the cost of the silicon raw material which is nowadays produced by standard methods of the semiconductor industry. New procedures for producing less expensive solar silicon can be divided into four groups characterized by different physico‐chemical purification techniques: (1) reduction of volatile Si‐H‐Cl compounds; (2) purification of technical grade silicon (98–99%); (3) reduction of hexafluorosilicates; (4) reduction of silicon dioxide. Among the ten solar silicon processes under discussion, the purification of technical grade silicon and the carbothermal reduction of silicon dioxide have the greatest scope for cost reduction; however, it remains to be established whether the necessary purity can be achieved on an industrial scale.
Anwendung elektronischer Rechner in der Chemischen Technik
Authors: Lübbert Andreas 
Published: December 2004

AbstractUse of computers in chemical engineering. It is shown by various examples from three directions of development how modern microelectronics, especially microcomputer technology, can be used effectively in chemical engineering applications. These are applications of microprocessors in complicated measuring tasks, the distribution of computing power in computer networks and the use of specialized processors.
Aufgaben der Produktionsleitebene in der chemischen Industrie
Authors: Hofmann Winfried 
Published: December 2004

AbstractThe plant management functions in chemical industry. The information flow can be structured by a layer model, comprising the plant management layer, the process control layer, and the field layer. The higher company management layer issues production orders which are detailed at the plant management layer with the aid of a formulation; amounts of materials required, equipment, personnel, and laboratory measurements are assigned as a prerequisite for production. These tasks are described in detail, the flow of information between the adjacent layers indicated, and the layer structure of other business units briefly considered.
Erforschung von Schadenfeuern flüssiger Kohlenwasserstoffe als Beitrag zur Sicherheit von Chemieanlagen
Authors: Schönbucher Axel , Brötz Walter , Balluff Christoph , Göck Dietmar , Schieß Norbert 
Published: December 2004

AbstractInvestigation of hazardous fires of liquid hydrocarbons as contribution to the safety of chemical plants. This article illustrates the danger potential of hazardous fires, such as pool‐and tank fires in chemical plants. The importance and the role of fluid dynamic organized structures for the combustion processes are presented. Experimental methods used for the visualization of these organized structures are also explained. The influence of such structures on the safety data, burning rate, maximum pool fire diameter, flame height and flame tilt, and the total radiative power is dealt with in detail. The point source model and the solid flame radiation model are discussed for calculation of the distance‐dependent irradiance of a pool fire. A new model, the parcel‐radiation model, considers the radiation of hot spots, soot parcels, and the effect of radiation blockage by cooler, unburnt fuel parcels. Application of the parcel‐radiation model leads to a calculated maximum irradiance of „E≈ 4 W/cm2, which is verified experimentally for most pool fires with diameters > 14 m. These irradiances are three times smaller than the values calculated by the solid flame radiation model. The consequences for safe separation distance between two adjacent pools are discussed.
Gastrennung mit Druckwechsel‐Adsorptionsanlagen
Authors: Riquarts Hans‐P. , Leitgeb Paul 
Published: December 2004

AbstractGas separation in pressure swing adsorption plant. In recent years gas separation in pressure swing adsorption plant has acquired considerable significance as an industrially implemented process. This is particularly true of plant for isolation of pure hydrogen from gas mixtures of various origins. Starting from the underlying principles, this contribution considers the various types of plant for hydrogen isolation, for obtaining carbon monoxide, for recovery of ethylene, for separation of oxygen or nitrogen from the air, and for ozone isolation.
Sicherheitstechnische Maßnahmen bei der thermischen Abluftreinigung
Authors: Hüning Werner 
Published: December 2004

AbstractSafety measures in thermal waste air purification units. Safety problems may arise in thermal waste air purification units from the occasional explosive nature of the exhaust gases, which may cause a flashback into the production plant. This must be avoided by the installation of safety devices that arrest a flashback. The number of such safety devices is determined by the probability of formation of explosive waste air, according to the zone classification of the explosion‐protection guide. The principal explosion arrestor devices installed between combustion chamber and production plant are liquid submersion systems, detonation barriers, and dynamic flashback‐free inlets into the combustion chamber, all of which must be operated under instrumental surveillance. This report presents a state‐of‐the‐art summary of all suitable procedures and safety devices permitting safe design of systems for thermal air cleaning problems encountered in practice.
Reaktivextraktion
Authors: Schügerl Karl , Hänsel Rolf , Schlichting Eberhard , Halwachs Werner 
Published: December 2004

AbstractReactive extraction. A brief survey of reactive extraction and its classification is followed by an account of the reactive extraction of organic solutes. As an example, the reactive extraction of salicylic acid with a secondary amine and NaOH is discussed. Equilibrium constants, overall mass transfer coefficients evaluated in stirred cells and on fixed, freely suspended and pulsated droplets, as well as mass transfer coefficients for the particular phases are investigated. The influence of droplet volume, solute concentration, pH value, and the fluid‐dynamic state of the droplet on the overall and fractional mass transfer coefficients are discussed and compared with various mass transfer models.
Aseptisches Verpacken von Lebensmitteln – Grundlagen und Stand der Technik
Authors: Reuter Helmut 
Published: December 2004

AbstractAseptic packaging of foods – fundamentals and state of the art. During the last two decades, a highly successful development has taken place in this area and aseptic packaging is today considered a normal component of technology in many areas of food industry. Aseptic packaging of food can be divided into two main areas of application: 1. Packaging of presterilized and sterile products. 2. Packaging of unsterilized products to avoid the external contamination. In most case, destruction of the microorganisms and spores attached to the surface by a lethal factor obeys the general logarithmic time law. For aseptic packaging of a given product, it is necessary to coordinate 4 factors, viz. the packaging material, the sterilization process for the packaging material surface, the packaging machine itself, and the operating environment of the machine: among these factors, the sterilization process is of greatest importance.
Sicherheitstechnische Aspekte der Prozeßleittechnik
Authors: König Jörg 
Published: December 2004

AbstractSafety aspects of process control. Safety aspects and safety strategies are becoming increasingly important for modern process control of chemical plants. With respect to configuration, installation, and maintenance, a classification of process control equipment according to the safety relevance turns out to be advantageous. Technical and especially organizational measures have to be adopted to ensure a high degree of safety. Beyond safety requirements in conventional process control engineering the increased implementation of modern control systems introduces new problems. Their information processing power, however, opens vast new opportunities, which are just beginning to be exploited.