摘要:

AbstractParticle deposition on droplets and fibres. The fundamental processes involved in deposition on fibres and drops are discussed and theoretical model calculations are presented. It is shown that approximative equations and diagrams permit fast estimation of degrees of collision and extent of adherence. Experimental studies confirm the model calculations.

ISSN:0009-286X    

DOI:10.1002/cite.330550302

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractProduction of impregnated catalysts as a chemical engineering task. Impregnated catalysts are the result of manufacturing processes involving a complex interplay of diffusion, viscous flow by capillary action, and solid state reactions. A knowledge of physical chemistry and drying technology permits systematic prediction of the necessary production steps in some detail. It is similarly possible to reduce the number of experiments needed to determine which variables are important and therefore have to be optimized. Thus it is at least possible to distribute the active components in the structure of the carrier in a manner that relates appropriately to the reaction requirements. This systematic prediction is limited in special cases where the active component of the catalyst changes its chemical nature during production. An example of this is when a catalyst requires an activation step.

ISSN:0009-286X    

DOI:10.1002/cite.330550303

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractFluidized‐bed firing technology – State of the art and prospects. After categorizing fluidized‐bed combustion according to process engineering criteria, the following features are then discussed on the basis of R&D results and of experience gained with demonstration units over the past four years: the range of feed coal qualities, combustion intensity, cleanness (SO2, NOx, CO, halogen, dust, disposal properties, and usability of residues), flexibility for partial load operation, and availability. The system‐inherent possibilities could be exploited to such an extent that initial commercial application is within reach. Furthermore, significant improvements seem to be possible. The intial results obtained with binding of fluorine are to be regarded as positive, large‐scale feasibility, however, still needs to be proven. Economic criteria are dealt with. The state of technology worldwide is discussed as well as modified experimental plants and facilities. Possibilities of further development are po

ISSN:0009-286X    

DOI:10.1002/cite.330550304

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractRecent results in mathematical modelling of liquid/liquid extraction columns. Flow in extraction columns is so complicated that it defies exact description. Methods have to be found for approximating the actual state, which can be accomplished by modelling. Approximations should be sought which closely approach reality, and yet can be formulated mathematically and solved by expenditure of a reasonable amount of effort. The development of models proceeded from the plug flow assumption via the theory of back‐mixing to mechanistic models, which should also correctly describe the fundamentals of the various processes. It is now also possible to simulate complicated processes, such as parameter changes along the height of the column. The models described in this article can be readily solved numerically. Only standard procedures are used which can be managed by minicomputer

ISSN:0009-286X    

DOI:10.1002/cite.330550305

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550306

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractTurbulent heat and mass transfer. Turbulent heat and mass transfer is inseparably connected with turbulent momentum transfer. Thus we again find the same problems as those encountered in the description of turbulent momentum transfer. Moreover, further difficulties arise because of the temperature and concentration fluctuations in addition to the velocity and pressure fluctuations. The problems are essentially experimental ones. It is much simpler to measure correlations of velocity fluctuations like the turbulence energy or the Reynolds shear stress than correlations of other fluctuating quantities. This is why attempts were made at an early stage to reduce the turbulent heat and mass transfer to the comparatively well understood turbulent transfer of momentum. Therefore the basic ideas concerning the modelling of the turbulent momentum flux are discussed at first. A brief introduction to concepts of the statistical theory of turbulence is also given. Finally some proposals to describe the turbulent heat transfer based on modelling assumptions are presented for example of turbulent tube flow. Turbulent mass transfer is only briefly touched upon because of the far greater experimental gaps opposing reliable modelling.

ISSN:0009-286X    

DOI:10.1002/cite.330550307

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550308

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550309

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550310

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550312

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY