Neuere technische Verfahren in der Kohlechemie

New technical processes in coal chemistry . The most important commercial basic processes of primary coal conversion are carbonisation, gasification, and hydrogenation. Some 450 mio t/a of coal are converted by coking in horizontal slot type ovens to 350 mio t/a of metallurgical coke for the reduction of iron ore in blast furnaces, coke oven gas, and some 20 mio t/a of coke oven benzole and coal tar as raw material for aromatics. The coke ovens are being developed to high-capacity coking reactors. New second generation processes for the gasification of coal and lignite have advanced to an industrial scale. A vapor-phase hydrocracking refining step has been integrated within the further developed process for the catalytic liquid-phase hydrogenation of coal. Plasma pyrolysis of high-volatile bituminous coal investigated on a semi-industrial scale yields acetylene. Pressure hydropyrolysis of coal currently being tested on a pilot plant scale generates high-aromatic liquid products. New processes for the upgrading of such liquids have been developed above all for aromatics from coal tar, e. g. for the production of naphthalene derivatives, and the conversion of polycyclic aromatic hydrocarbons into the technical carbon products carbon black, electrographite, carbon electrodes, and carbon fibres.     

Großtechnische Herstellung von Reinstsilicium

Large scale production of hyperpure silicon . Silicon still remains one of the most important elements in use in semiconductor technology. Worldwide production of silicon amounts to more than 1000 t/year. Its use in semiconductor components calls for special requirements, such as extreme purity in the ppb-range, absolutely perfect crystals, and narrow dimensional tolerances and special surface properties of fabricated silicon slices. Reaction of 95% pure metallurgical grade silicon and hydrochloric acid results in trichlorosilane, which is then purified by distillation. This is subsequently subjected to a reductive cracking process in order to produce hyperpure polycrystalline silicon. Monocrystalline silicon rods are then manufactured by one of two crystal growing methods, either by crucible pulling (Czochralski) or by float zoning. The single crystals thus obtained are then sliced by diamond cutting machines. Depending on their final use the slices are then processed by lapping, polishing, epitaxy, etc.     

Die technische Herstellung von Äthylencarbonat

Technical Production of Ethylene Carbonate The process of Chemische Werke Hüls AG, Marl, for technical production of ethylene carbonate in a 4000 t/annum plant is described. In this plant the efficiencies achieved with a single pass are of the same order as those in other known processes in which the product is recirculated through the reaction system. The possible applications and uses of ethylene carbonate are reported.     

Entwicklungen in der Technologie zur Herstellung von Brennstoffen aus kommunalen Abfällen

Developments 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.     

Neuere Entwicklungen auf dem Gebiet der Raffination der Speiseöle

Novel Developments in Refining of Edible Oils The requirements for the physical refining of edible oils are analyzed. One major requirement is the more or less complete removal of phospholipids, lipoproteins, free and bound carbohydrates, traces of heavy metals and organic pigments. Acid degumming processes, e. g. Super-Degumming and Special-Degumming as also the Alcon-Process are examined on their mechanism and efficiency on the background of the above mentioned requirements. Additionally, the process of ultrafiltration of edible oil miscella is presented as a novel development, which fulfills the requirements for physical refining very efficiently. The ultrafiltration process, which exploits the principle of reversed osmosis, removes phospholipids and other numerous impurities present in crude oils in one single unit-process. The principle and the modification possibilities of this process are discussed.     

Neuere Entwicklungen auf dem Dispersionsfarbengebiet

Recent Developments in the Field of Dispersion Colours With an aim to achieve a further improvement of the properties of dispersion colours, styrolacrylate dispersions were introduced during the mid-sixties, and, recently, pure acrylate dispersions were brought to the market. Utilization of the suitable coating properties of these binder dispersions led to considerable improvement of properties of the known dispersion colours and extended their field of application. This is especially the case with pure acrylate colours which were being developed in such a manner as to use them in oil paints. The new development is a step in the effort towards processing of coating agents in a way which is acceptable to men and the environment, since the paints containing more or less physiologically undesirable solvents are thus replaced by water-containing colours.     

Simulation von Extraktionskolonnen in der industriellen Praxis

The design of extraction columns is usually based on lab‐scale and pilot‐plant experiments. A new alternative design approach is based on lab‐scale experiments with single drops to quantify mass transfer and drop sedimentation. From these experiments, liquid‐liquid system specific parameters for the simulation of the extraction column are obtained. This approach has been successfully validated for standard‐test systems and shall now be established in industrial practice. As part of this, separation performance and flooding limits measured with pilot‐plant experiments are compared to simulation results that are obtained on the basis of single‐drop experiments. The challenges that come with the simulation of industrial systems are presented and discussed.     

Fischer-Tropsch-Synthese. Neuere Untersuchungen und Entwicklungen

Fischer-Tropsch synthesis – Recent studies and Developments . This article surveys some results of recent research and new lines of development in Fischer-Tropsch synthesis. Most interest is focussed on variants synthesis showing high selectivity of C₂-C₄ alkenes or C₅-C₂₀ 1-alkenes or Diesel oil. In the last decade catalysts of improved alkene selectivity have been developed. Also the dependence of selectivity on process parameters such as pressure of hydrogen and carbon monoxide and temperature has been investigated in order to find appropriate conditions of operation for a synthesis of high selectivity. Some preliminary process designs are discussed.