摘要:

AbstractBreakthrough in adsorption beds: Methods of calculation and influence of operation parameters. Calculation of the breakthrough curve of a fixed bed adsorber is performed numerically for industrial applications. Calculation methods are known for solution of the four coupled differential equations and can be performed within a considerable but acceptable time on todays powerful computers. Nevertheless, the present article considers the analytical description and discussion of the individual parameters because the influence of the large number of parameters on the breakthrough curve cannot be appreciated. These relations must be known if individual operating parameters are changed or if a laboratory unit is scaled up to an industrial plant. The influence of the following effects on the breakthrough curve are considered and approximate solutions are given in order to at least estimate the influence: axial dispersion; shape of the isotherms (linear, Langmuir, irreversible), constant pattern conditions; resistance to mass flow (diffusion and transfer); multicomponent adsorption; concentration and temperature fronts; non‐isothermal adiabatic adsorption; adiabatic equilibrium curve (sorption pathway). Mathematical treatment necessitates reference to the literature. The relations of importance for plant and design are presented her

ISSN:0009-286X    

DOI:10.1002/cite.330590103

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330590102

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractMass separation with supercritical gases (gas extraction). The solvent power of dense gases is considered with ongoing interest for use in technical processes. A great number of gaseous solvents are available, especially if solvent mixtures are included. These solvents can be used in one‐stage or multiple‐stage processes, running batchwise or continuously in countercurrent process. Design the equipment and simulation of the process requires correlation of the underlying phase equilibria. Remarkable progress has been achieved in this field. In some cases data on mass transfer have also been published. Several companies supply turnkey plants or specialized equipment from laboratory to pilot scale. Commercial plants are used extracting natural products and mineral oil residue process

ISSN:0009-286X    

DOI:10.1002/cite.330590104

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractCAD and plant engineering. State of the art, problems, and prospects. CAD was first used for special tasks, that is for especially sensitive design, e. g. in the aircraft industry, or mass‐produced articles, e. g. in the automotive industry. For about one decade, CAD has been used economically in all areas of design. This paper describes the state of the art of CAD use for plant engineering. It may be seen as the termination of a thorough test. Now the time has come to decide on the future use of CAD. Problems encountered are therefore reported. The prospects of CAD are outlined on this basi

ISSN:0009-286X    

DOI:10.1002/cite.330590105

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractDirected exploitation of biological systems. During the past few decades, our knowledge of molecular process responsible for genetics has increased dramatically. Discovery of the giant molecule deoxyribonucleic acid – abbreviated as DNA – as the carrier of genetic information heralded in a development which nowadays permits us to effect directed changes in the genetic material of an organism. Thus we can provide easily cultured microorganisms with genes which were previously located in a completely different genetic environment. This helps us to obtain high yields of proteins or other substances which were formerly very difficult to obtain. Higher organisms such as animals and plants can also undergo modification of their genetic equipment. This adds a new dimension to the breeding of such species. Above all, genetic engineering provides new insights into the enormously complex interplay of molecules which go to make up a living cell. The resulting understanding of life processes on a molecular level permits recognition of malfunction and therapy of the ensuring disease by new drugs. In addition to these positive aspects, genetic engineering provides scope for conducting experiments whose ethical implications demand very earnest considerat

ISSN:0009-286X    

DOI:10.1002/cite.330590106

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractEconomic and process engineering advantages of extrusion cooking in comparison with conventional processes in the food industry. Extrusion cooking is introduced as a modern high‐temperature short‐time process. Possible process steps in extruder machine systems, such as continuous conveying, mixing, homogenizing and reactions, mechanical and thermal energy dissipation for plasticizing and modifying biopolymers, are explained. This process creates new products with completely new textures, for example in the snack and breakfast cereal sector, while on the other hand the extrusion process competes with long‐standing conventional processes. The latter work slowly with low pressures, low temperatures and energy dissipation with high water contents in large batch‐operated machines. The quality of extruder‐cooked products depends on the extrusion system. The self‐cleaning corotating twin‐screw extruder with its narrow residence time spectrum is the optimum system. However, the counter‐rotating intermeshing machine has certain advantages for products of low viscosity. The cooking time at high temperature is a matter of seconds, which serves to maintain the properties of the ingredients and active substances, while ensuring fast destruction of microorganisms. The end‐products have a long shelf‐life on account of their low process moisture content. Continuous extrusion cooking has economic advantages mainly because it replaces many batch processes and because extrusion is carried out entirely or almost entirely with the final moisture content, thus avoiding the necessity to evaporate huge

ISSN:0009-286X    

DOI:10.1002/cite.330590107

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330590108

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractUsing of programmable pocket‐calculators for process engineering calculations. Part of a chemical engineer's daily work are repeated calculations to illustrate special relations. Suitable for this purpose are programmable pocket computers, which allow easy and quick programming by the user. This contribution gives brief instructions for creation of short and more complex programs in addition to those found in the user's manual. Independently of calculator type and nature of the problem, the single steps required to get a complete program are described. Using a special example from chemical engineering, the optimal pathway from the algorithm to the program listing is shown for two calculator type

ISSN:0009-286X    

DOI:10.1002/cite.330590109

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330590110

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330590111

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY