ISSN:0009-286X    

DOI:10.1002/cite.330620902

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractDevelopments in dosage of bulk solids.Dosage of bulk solids is a fast developing field of process‐ and production automation. Developments are determined directly by the current demands of the production process, with the properties of the bulk solids and the process itself playing an important role. A survey of proven dosage techniques from the viewpoint of the operating principles, properties, applications, and limitations demonstrates the great variety of problem solutions. An important difference between the individual dosage techniques is the nature and accuracy of mass limitation. The most accurate techniques are the gravimetric dosage methods, with discontinuous weighing giving the greatest accuracy. Developments have been greatly influenced by the state of weighing cell techniques, weighing electronics and computer engineering. The development of measured data acquisition and processing of control, and of instrumentation are described, compared, and assessed. A trend towards system responsibility and development on the part of manufacturers is noted. A accurate dosage of bulk solids requires constant flow of the solids and finely adjustable control devices. The principal interferences in bulk solids flow and measures for their avoidance are shown by means of examples. Successful solution of dosage tasks ultimately requires agreement between manufacturers and processors with regard to definition, determination, and control of dosage accuracy during calibration and during long term operatio

ISSN:0009-286X    

DOI:10.1002/cite.330620903

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractInfluence of thermophysical data on the design and operation of distillation columns.It has become common practice in the petrochemical industry to utilize highly developed process simulators for the design of individual pieces of equipment or entire processes. Apart from actual model development, attention focusses on the calculation and use of efficient solution and converging algorithms in the development of such process simulators. Although frequent reference is made to the importance of the underlying material data in the literature and in practical applications there exist only scattered studies giving a suitable choice of the available substance data models and the sensitivity of the process variables to inaccuracy and uncertainty of the material data and the material data models. The present article illustrates the influence of material data (choice of model, sensitivity) for the example of the design and operation of distillation columns and several methods and recommendations are given for fast estimations. With the aid of appropriate examples, the influence of uncertainties in the underlying measured data and the phase equilibrium models on various process variables (plate number, reflux ratio, distillate and sump concentrations) is demonstrated.

ISSN:0009-286X    

DOI:10.1002/cite.330620904

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractMicroporous filters media for cake filtration.Improved knowledge about filtration conditions, capillary phenomena in filter cakes and in filter media, as well as the properties of membranes permit the use of microporous membranes in cake‐forming filtration. This allows removal of moisture without passage of gas and yields a particle‐free filtrate. Apart from metallic and ceramic membranes, polymeric membranes prove highly suitable as microporous filter media since they permit utilization of the entire range of filter equipment. The present article considers first the fundamentals of cake‐forming filtration, then surveys the various membrane systems, and finally discusses process‐engineering aspects of filtration with microporous filte

ISSN:0009-286X    

DOI:10.1002/cite.330620905

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractTransient processes in modelling heterogeneous catalytic kinetics.It is often difficult to obtain mathematical models to describe the dynamics of heterogeneous catalytic reactors. Kinetics determined under steady‐state conditions are normally not valid for the transient behaviour of catalytic reactions. In order to find valid kinetic models, information is needed about the adsorption‐desorption processes and the formation of intermediates on the surface. To get single step models, experiments have to be carried out under transient or oscillatory conditions. This is discussed for different examples taken from the literat

ISSN:0009-286X    

DOI:10.1002/cite.330620906

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330620907

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330620908

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330620909

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330620910

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330620911

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY