摘要:

AbstractThis paper presents a critical review of the developments in the mathematical modeling of gas‐solid noncatalytic reactions with particular emphasis on recent trends in the subject. A number of models proposed for analyzing this class of reactions have been reviewed with a fairly detailed discussion of the methods of incorporating structural changes which occur in the solid with the progress of reaction. The present status on the modeling of various types of complex gas‐solid reactions is reviewed. Also the paper points out a number of areas in which future research may be needed. The review concludes with a critical discussion on the type of experimental data necessary for model verification and some comments on the choice of model for a given sys

ISSN:0001-1541    

DOI:10.1002/aic.690280602

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractDuring their industrial processing, polymer liquids are usually subjected to complex flow histories. In principle, these can be taken into account in the constitutive equations. In reality, difficulties arise for complex flows. This fact can be illustrated by the spinning process. Here, experiments are presented in which the upstream section of a spinning device has been changed systematically. A constitutive model and a calculation procedure are suggested that permit an analysis of the upstream effects in the spinning flow. The results indicate that this analysis predicts well the spinning dynamics in the present experiments, using shear flow characteristics for the liquids. It is also concluded that the spinning flow can be altered by upstream changes. The changes in structure seem to be the most pronounced ones.

ISSN:0001-1541    

DOI:10.1002/aic.690280603

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractThe local contact characteristics between the bed emulsion and the tube surface for horizontal tubes immersed in fluidized beds were investigated experimentally. The measurements indicated that the contact dynamics change significantly with circumferential position, gas flow rate, particle size and system pressure. From the experimental data, quantitative information on the local fluidization behavior were generated for use in heat transfer models.

ISSN:0001-1541    

DOI:10.1002/aic.690280604

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractThe mathematical basis was derived for the experimental measurement of the “Slope Condition” and of the “Dynamic Condition” of the thermal stability criteria in a laboratory‐scale internal recycle reactor. This work also resulted in clearer interpretations and simpler expressions for the two stability criteria. The method was experimentally demonstrated on the example of the low pressure methanol synthesis. Only seven experiments were needed to evaluate the stability criteria of this reaction for which the kinetics i

ISSN:0001-1541    

DOI:10.1002/aic.690280605

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractAn experimental and theoretical study is presented of the time dependence of air pressure in a bubbler tube used to measure the liquid level in a tank. The observed time dependence of the air pressure is a superposition of two components. The first component is a repeated slow rise and sudden fall in the air pressure that is associated with bubble growth and breakoff. It is the sudden breakoff that generates the second component consisting of damped oscillations associated with sound waves in the air interacting with an oscillating flow of the liquid. The air pressure during bubble growth is described theoretically. This result is combined with the gas law to predict the functional form of the slow pressure rise; this prediction agrees with experiment. An equation for the oscillation frequencies is derived, solved, and compared with experiment; agreement is within the measurement accuracy of 5%.

ISSN:0001-1541    

DOI:10.1002/aic.690280606

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractA gravimetric technique has been developed for measuring three phase vaporice‐hydrate (VIH) equilibria. This technique has been used for measuring VIH dissociation pressures for propane and isobutane hydrates to temperatures as low as 241.4 K. Kihara parameters, based upon the experimental dissociation pressure data, have been obtained. Because the range of experimental three phase equilibrium data has been considerably extended, the parameters based on this data should be more useful in predicting hydrate dissociation pressure

ISSN:0001-1541    

DOI:10.1002/aic.690280607

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractInput multiplicities in process control occur when more than one set of manipulated parametersmcan produce the desired steady state outputsc. They are directly related to the stability and desirability of any intended loop pairing ofm's andc's. A chemical reactor example illustrates the phenomena.

ISSN:0001-1541    

DOI:10.1002/aic.690280608

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractThe concept of using optical fibers to distribute light within heterogeneous photo‐assisted catalysts is extended to photo‐electrochemical cells. The potential drop in a semiconductor photo‐electrode is predicted for various types of ohmic electrical contacts, and the optimum contact location is determined. The variation of electrical conductivity with temperature in non‐isothermal bundles of semiconductor‐coated optical fibers is c

ISSN:0001-1541    

DOI:10.1002/aic.690280609

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractWhen a small drop or bubble approaches a solid surface, a thin liquid film forms between them, drains, until an instability forms and coalescence occurs. Lin and Slattery (1982a) developed a hydrodynamic theory for the first portion of this coalescence process: the drainage of the thin liquid film while it is sufficiently thick that the effects of London‐van der Waals forces and electrostatic forces can be ignored. Here the effects of the London‐van der Waals forces are included. The resulting theory describes the evolution of the film profile, given only the bubble radius and the required physical properties. The inclusion of a positive disjoining pressure results in better descriptions of the film profiles measured by Platikanov (1964) for air bubbles pressed against glass plates. When the disjoining pressure is negative, an unstable draining film evolves and finally ruptures. Unfortunately, there are no experimental data with which to compare our predicted coalescence ti

ISSN:0001-1541    

DOI:10.1002/aic.690280610

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY

摘要:

AbstractA procedure using only fundamental physico‐chemical data is developed for the design and analysis of packed columns used for solvent recovery in gas purification processes involving chemical reaction. The results of 173 experiments on the mass transfer performance of a pilot‐scale regenerator stripping CO2from loaded monoethanolamine solutions are reported and compared with model predictions. Anomolous responses of the overall mass transfer coefficient to changes in process conditions are observed and explained by the process model which is found to predict correctly both the magnitude of the coefficient and its respo

ISSN:0001-1541    

DOI:10.1002/aic.690280611

出版商:American Institute of Chemical Engineers    

年代:1982

数据来源: WILEY