摘要:

AbstractTransport processes in membranes for reverse osmosis. The transport processes of electrolytes and undissociated polar organic compounds in membranes for reverse osmosis in individual or mixed systems are described with the aid of model equations. In addition the influence of the structure of the polymer used as membrane on the transport of the dissolved material is discussed from the viewpoint of interaction of dissolved material, solvent and membrane surface.

ISSN:0009-286X    

DOI:10.1002/cite.330500802

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractHeat and mass transfer in pool flames. Theoretical and experimental concept of heat and mass transport in liquid pool flames are reviewed. The heat and mass transfer processes in the interface between flame and liquid fuel are outlined, and the concept of the burning rate as a parameter for the quantitative description of a pool fire is discussed. The methods of calculation and experimental results concerning flame length and flame shape as well as buoyancy forces are described. In pool flames, a lower region (flame neck) and an upper region (flame plume) are distinguishable. Both the flame neck and the flame plume show a flow pattern obtained from short or long periods of observation. The flow patterns of the flames have been measured by the techniques of equidensitometry and Laser‐synchronous‐interferometry. The flow pattern observed over a short period of time gives an insight into the eddy field of the pool flame whose turbulence is measured. The flow pattern observed over a long time is obtained from time averaged values of temperature, heat radiation, concentration

ISSN:0009-286X    

DOI:10.1002/cite.330500803

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractReactions in distillation columns. Reaction columns are an interesting alternative for numerous reactions, and they have often proved economically advantageous. The effects resulting from superposition of reaction and distillation are demonstrated for a few examples and the industrial exploitation of such a system is illustrated. In comparison to the processes in actual distillation columns the processes in reaction columns are extremely complex. It is therefore advantageous in industrial engineering design to have suitable mathematical models at hand. Control problems can be overcome by profile control or by dynamic detectors.

ISSN:0009-286X    

DOI:10.1002/cite.330500804

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe energy crisis, and developments in the phosphorus industry for the economic production of basic products. A general shortage of power has culminated in attempts to switch over from energy intensive to energy‐saving processes. This is exemplified with reference to the field of inorganic phosphorus chemistry. Modern recrystallization processes for making wet‐processed phosphoric acid, proceed via the calcium sulfate semihydrate stage, and yield crude phosphoric acid in increased concentration. The steam normally required for concentrating the acid is thus saved. Heat of neutralization is utilized for evaporating water, for example, in a TV A process for making ammonium polyphosphate from commercial crude phosphoric acid and ammonia. Economic evaluation data reflect the economy (reduction of costs) of the above processes in comparison with those used heretofore. The purification of wet‐processed phosphoric acid by an improved precipitation method – particularly in the intermediates sector – and by modern extraction techniques are described as alternatives to the electro‐thermal production of phosphoric acid. A detailed description is given of one such process, where amyl alcohol is used as

ISSN:0009-286X    

DOI:10.1002/cite.330500805

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractModelling of isothermal fixed bed adsorbers. The effective adsorption velocity in porous solids is determined primarily by the adsorption equilibrium coupled with bulk diffusion, Knudsen diffusion, and surface diffusion in the particles. Adsorption and mass transport may follow different mechanisms for different combinations of gaseous (fluid) and solid phases and for different pore size distributions. For the industrially important cases models were developed and discussed for isothermal fixed bed adsorbers. The balances of the different models show different mathematical structures, so that different mathematical evaluation methods are necessary for determination of the breakthrough curve. Computed results of the models are discussed. The evaluation of the breakthrough curves is needed for parameter estimation from laboratory scale experiments and for the design of industrial adsorbers with known parameters.

ISSN:0009-286X    

DOI:10.1002/cite.330500806

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractLarge 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, et

ISSN:0009-286X    

DOI:10.1002/cite.330500807

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330500808

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330500809

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330500810

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330500811

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY