摘要:

AbstractPerformance indices of various countercurrent extraction columns.The permissible working range and the separation efficiency achievable therein are characteristic indices for the performance of extraction columns. An introductory account of the design principles, especially of columns supplied with mechanical energy, is followed by an illustrative discussion of the influence of operational and constructional parameters and of material properties on the loading range and the separation efficiency attainable therein. Then follows a section comparing the efficiencies of various columns as a function of loadability for a variety of material systems. These comparisons are valid only for certain parameters. Hence, the changes occurring on variation of these parameters are also considered qualitatively. In conclusion, the separation efficiencies of two newly developed columns are examined with a view to establishing whether the dependence upon loading has changed relative to conventional columns.

ISSN:0009-286X    

DOI:10.1002/cite.330561202

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330561203

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractOn‐line analyzers as transducers.The term transducer is employed frequently by manufacturers and users of measuring instruments and measuring systems. It is generally understood to be an element of a measuring chain which is loaded by as many functions as possible in order to set the rest of equipment free for other tasks. If demands associated with this are not mutually compatible, compromises must be sought. The article starts from the definition of the term transducer, compares this with the results of a discussion on the characteristics such instruments display in practice, and finally, using characteristic examples from on‐line analyzers, outlines the ideas and assessments which stem from such an analy

ISSN:0009-286X    

DOI:10.1002/cite.330561204

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractSizing by sifting with screens.Viewed physically, screening comprises superposition of segregation, diffusion, and passage through the screen. Frictional and cohesive forces have to be overcome and the coarse feed material transported over the screen, primarlily by circular, elliptical, or linear vibration. The specific screening performance and the sharpness of separation prove to be a measure for the quality of screening. There are three uses for screening: protective screening with mean particle sizeDm≪ meshwwith a simultaneous wish for high screen performance; classification withDm≈wwith a desire for greater sharpness of separation; and dust removal withDm≫wand the problem of deagglomeration, i. e. separation of fines from the screened material. The maximum screen performance can be calculated for the coarse range; it is attainable with most screening machines. A problem encountered in the medium to fine size range is prevention of blinding of the screening machine and deagglomeration of sieved material, with attrition phenomena deserving attention. A range of machines is available: casting, planar, tumble, agitator screening machines are available, as are those with deforming screens, those utilizing centrifugal forces, and, as the latest addition, flow screening. New developments concentrate on fine screening, e. g. screening machines with direct activation of the screen fabric, tumble screening machines, combinations of mechanical and pneumatic screening extending through to pure flow screening. Plastic screens made of polyurethane are of advantage for wet screening; they exhibit greatly reduced wear. Safety requirements are met by silenced and explosion‐proof‐screening

ISSN:0009-286X    

DOI:10.1002/cite.330561205

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractIndustrial use of zeolites in petrochemical processes.The cost rise of feedstock triggered by the energy crises as well as increased environmental awareness have accelerated the development of new, environmentally more acceptable processes and the introduction of improved catalysts in the petrochemical industry. In this regard, zeolites have an important contribution to make as catalysts. The utilisation of zeolites in large‐scale technical operations in crude oil processing and petrochemistry is reviewed and the advantages of these catalysts and their influence upon process design are presented. Hydrocracking, dewaxing, methanol‐to‐gasoline (MTG), the Mobil‐Badger process and xylene isomerisation are discussed. A description of the conversion of methanol to olefins indicates that zeolite catalysts will continue to be of great interest in ch

ISSN:0009-286X    

DOI:10.1002/cite.330561206

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330561207

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330561208

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330561209

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330561210

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330561211

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY