摘要:

AbstractThe review is concerned primarily with some aspects of mixing in continuous crystallizers and recognizes the central importance of the interplay between the mixing and crystallization (or precipitation) processes in the design and performance evaluation of industrial crystallizers. The paper adopts a unifying treatment from a chemical reaction engineering viewpoint in which the Lagrangian approach to mixing in crystallizer systems is emphasized. The concepts of macro and micromixing applied to crystallization configurations have been introduced with due emphasis on the modeling efforts. The present state of knowledge in various related areas of continuous mixing is assessed to help direct future trends in research.

ISSN:0001-1541    

DOI:10.1002/aic.690320502

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractSeveral new algorithms for the detection of gross errors in process data are presented and applied to an industrial steam‐metering system by means of computer simulation. A number of algorithms that have appeared in the literature are also applied to the steam‐metering system, and the performances of the various algorithms are compa

ISSN:0001-1541    

DOI:10.1002/aic.690320503

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA single‐pellet, moment technique is presented for evaluating reaction rate constants, effective diffusivities, and adsorption equilibrium constants for gas‐solid noncatalytic reactions. Experimental pulse‐response data for the reaction of SO2with activated soda at 473 K were obtained to illustrate the method. The results show that intraparticle diffusion is the controlling mechanism for this reaction. The value of the Thiele modulus for axial transport was found to be 8.6 for a cylindrical pellet of porosity 0.56, tortuosity 2.3, and length 3 ×

ISSN:0001-1541    

DOI:10.1002/aic.690320504

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper describes reactive flow in permeable media based on a numerical model that assumes local thermodynamic equilibrium. The model simulates single‐phase, one‐dimensional flow with greater generality than any model in the current literature. The mathematical foundation for the formulation is discussed in some detail. Results for hypothetical examples demonstrate that ion exchange and precipitation/dissolution of solids can interact to produce wave behavior not possible with either phenomenon alone. An important application involving both ion exchange and precipitation/dissolution is alkaline flooding. Model predictions for several laboratory alkaline floods indicate that the assumption of equilibrium is justified for these experiments. Simple calculations based on the equilibrium theory provide estimates of pH loss and hydroxide penetration dista

ISSN:0001-1541    

DOI:10.1002/aic.690320505

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractConcentration‐dependent activity coefficients were used in conjunction with dilute‐solution transport equations to show the effect of degeneracy on the apparent physical properties of semiconductors and on the performance of photovoltaic cells. The approach presented here allows convenient treatment of degenerate semiconductors in a manner that is both thermodynamically consistent and consistent with the Fermi‐Dirac distribution for electrons. These calculations show that neglect of the concentration dependency of the activity coefficients has a large effect on the calculated values for local concentrations in a photovoltaic device, but affects the calculated values of power density and cell potential only slightly. Neglect of the concentration dependency of the activity coefficients does have a significant effect on the calculation of the resistivity of the semicond

ISSN:0001-1541    

DOI:10.1002/aic.690320506

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractGlobal gas‐liquid mass transfer parameters,kLaandawere determined in an organic liquid in which finely divided solid particles were suspended in a mechanically stirred vessel. The productkLaandaboth decreased linearly with solids loading; both were independent of particle size and particle density. Gas holdup was independent of solids loadin

ISSN:0001-1541    

DOI:10.1002/aic.690320507

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThe Lagrangian dispersion function in turbulent flow can be determined from measurements of the probability that a particle which is observed in a small volume is not observed in a similar size volume downstream. In this work a single‐detector method is proposed to detect the particle arrivals in a multiple series of scattering volumes; the probability can be determined from the digital record over a long time compared to the turbulent integral time scale. The method is tested at locations downstream of a water spray nozzle and a submerged jet of dilute polymer solution

ISSN:0001-1541    

DOI:10.1002/aic.690320508

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractAn analytical, theoretical investigation regarding periodic finiteamplitude (nonlinear) waves in a Newtonian, isothermal liquid film flowing along a vertical wall is presented. The periodic solution found provides full information regarding stability, wavelength, wave velocity, and wave amplitude as expressed exclusively in terms of physical constants and flow rate.

ISSN:0001-1541    

DOI:10.1002/aic.690320509

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA centrifugal method for fractionating fine (<10 μm) particles by size and/or density is described. Periodic, bidirectional flow through a continuously spinning coiled tube splits fine particle suspensions into two fractions. Proof‐of‐principle experiments with zeolite powder have demonstrated successful concentration of aqueous dispers

ISSN:0001-1541    

DOI:10.1002/aic.690320510

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA general theory is presented for the prediction of effective axial conductivity and overall radial heat transfer coefficient for fluid flow through packed beds, under either transient or steady state conditions. The parameters to be used in each case may be quite different, depending on the dominant phase for heat transfer. The theory unifies all previous results and explains conflicting conclusions arrived at by different workers. The ability of a pseudohomogeneous model to reproduce packedbed transients is shown to depend upon the choice of effective parameters.

ISSN:0001-1541    

DOI:10.1002/aic.690320511

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY