摘要:

AbstractThe successful design and operation of a gas‐liquid‐solid fluidized‐bed system depend on the ability to accurately predict the fundamental properties of the system, specifically, the hydrodynamics, the mixing of individual phases, and the heat and mass transfer properties. Identification of the flow regimes under which the system operates is crucial to an understanding of both the variations of these properties and overall system performance. This timely, comprehensive review describes in a systematic manner the status of fundamental gas‐liquid‐solid fluidization behavior. This review also discusses the areas in which current knowledge is deficient and further research

ISSN:0001-1541    

DOI:10.1002/aic.690310102

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractThe modified Enskog theory of van Beijeren and Ernst for dense fluid mixtures of rigid spheres is applied to diffusion of inert, nonadsorbing gases in microporous “leaky” membranes. Utilizing the concept of a dense dusty gas, the resulting expressions for the permeability and flux ratio illustrate the influence of steric hindrance on the transport process. The results obtained serve as corrections to the original dusty gas model of Mason and oth

ISSN:0001-1541    

DOI:10.1002/aic.690310103

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractA model is developed to study holdup in intermediate storage as a function of system parameters such as processing unit delay times. General results concerning the periodicity of the required storage volume, the allowable unit delay times, and the calculation of the volume are presented. Analytical expressions for the limiting volume are obtained for several special network configurations. A simple upper bound is derived for purposes of quick estimates of the limiting volume for the general case, and a gradient based algorithm is reported for obtaining the minimum volume schedule for general networks.

ISSN:0001-1541    

DOI:10.1002/aic.690310104

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractThe hydrodynamics of cocurrent gas‐liquid flow in packed beds is analyzed by extending the concept of relative permeability to the inertial regime.The relative permeabilities of the gas and liquid phases are functions of the saturation of the liquid phase. These functions are found from an analysis of experimental data. The relations obtained are used to develop empirical correlations for predicting liquid holdup and pressure drop in gas‐liquid cocurrent downflow in packed beds over a wide range of operating conditions. The correlations proposed give very good results when compared to experimental data yielding, in general, mean relative deviations lower than existing correlations. In addition, a new equation is proposed for predicting static holdup in packed beds which is based on a more physically realistic characteristic length than that used in previous stud

ISSN:0001-1541    

DOI:10.1002/aic.690310105

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractWith the aid of nonuniform DC electric fields, an improved bubble disruption and dispersion technique has been developed for dielectric fluid bubble column reactors. The basic mechanisms which lead to bubble disruption and dispersion in the system have been studied both experimentally and theoretically. The influence of operating variables, liquid properties and electrode geometry on the present applied electric field method has been conducted. The efficiency of power consumption by using the present technique has also been revealed.

ISSN:0001-1541    

DOI:10.1002/aic.690310106

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractThe steady‐state behavior of a multivariable process system imposes certain necessary conditions on its dynamic behavior, particularly in any feedback control system containing integral action. These conditions are derived in general and compared with previous restricted results. A more flexible design view is allowed by the general resul

ISSN:0001-1541    

DOI:10.1002/aic.690310107

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractTracer diffusivities measured with the Taylor dispersion technique are reported for carbon tetrachloride, s‐trioxane, 12‐crown‐4, 15‐crown‐5, and 18‐crown‐6 in acetonitrile, benzene, and chlorobenzene across ranges of temperature. It is demonstrated that Stokes' law corrected with a microfriction factor successfully accounts for the diffusion behavior of even disk‐shaped crown ethers. Solute and solvent molecules being effectively spherical in the context of Stokes' law, the tracer diffusion of crown ethers is found to be satisfactorily represented by a rough‐hard‐sphere model for molecular diffusion. The degree of success increases with decreasing solvent polarity. The diffusion data for carbon tetrachloride are also used to extend the basis of the recently developed reduced equation for the tracer diffusion of nonelectrolytes in liquids over wide

ISSN:0001-1541    

DOI:10.1002/aic.690310108

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractA radiotracer‐based method of measuring local particle deposition profiles and reentrainment rates in an electrostatic precipitator has been developed and demonstrated. In tests performed on a pilot‐scale precipitator, differences in local deposition profiles obtained with and without a predeposited layer of dust on the plate were observed. Rates of reentrainment due to gas friction (aerodynamic drag) and to particle impaction on the plate were measured separately, and correlated with a semiepirical formula. Both friction and impaction reentrainment rates were found to vary as powers of the difference between the gas velocity and a minimum velocity required for reentrainment. The impaction reentrainment was found to vary as a power of the inlet dust load

ISSN:0001-1541    

DOI:10.1002/aic.690310109

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractA model is presented which relates the crystal size distribution (CSD) from a mixed–suspension, mixed‐product‐removal (MSMPR) crystallizer to the distribution of growth rates. This model is based on the assumption that individual contact nuclei have some inherent growth rate which remains constant, but the growth rate may vary from crystal to crystal. The crystal size distribution can be calculated from prior knowledge of the growth rate distribution. Even a limited knowledge of only the coefficient of variation and the mean growth rate permits an approximation of the expected crystal size distribution. Conversely, estimates of the mean and variance of the growth rate distribution can be determined from the moments of the CSD from an MSMPR crystal

ISSN:0001-1541    

DOI:10.1002/aic.690310110

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractThe separation of mixtures of helium and methane using a single column of activated carbon in a pressure swing adsorption process was studied experimentally. Process performace was predicted with an average error of 10% or less by a local‐equilibrium well‐stirred cell model in which dead volumes at the feed and product ends of the column were accounted for. Systematic differences between experiment and model were ascribed to omission from the model of flow resistance and heat rele

ISSN:0001-1541    

DOI:10.1002/aic.690310111

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY