摘要:

AbstractIn recent years much research has been carried out in combining electrochemical processes with chemical engineering techniques, and in general, to apply principles of analysis and design of this discipline in search for new electrochemical technologies. This paper reviews seven major areas of activity in modern applied electrochemistry where the chemical engineering approach has been successful: Fluidized bed electrochemical reactors; Bipolar particulate reactors; Pulsed electrochemical reactors; Gas phase electrochemical reactors; Electrocrystallization and electrodissolution; Enhancement of heat and mass transfer in electric fields; dynamics, modelling and optimization of electrochemical reactors.

ISSN:0008-4034    

DOI:10.1002/cjce.5450510501

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractThe pressure drops associated with the suspension velocities for single, hydrodynamically suspended spheres were measured for a range of steel spheres in a 5.3 cm diameter vertical glass tube. Nineteen different sphere to tube diameter ratios (d/D) were investigated ranging from 0.191 to 0.967. Three different liquid media were used: pure water, and two polyacrylamide solutions of concentration 25 wppm and 50 wppm of Reten 423.In the range 0<(d/D)0.7 the drag coefficient was not affected. The available data for air, water and polymer solution were correlated with an equation explicit in pressure drop, and the agreement between theory and experiment was found to be excellent.

ISSN:0008-4034    

DOI:10.1002/cjce.5450510502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractFunctional relationships for coalescence rate dependence on drop size and hold‐up were derived via the collision rates and coalescence efficiency. Experiments in an agitated vessel indicated the coalescence rate to be controlled by the viscous flow regime and, per unit drop concentrations, to be proportional to the third power of the sum of the diameters of the two coalescing drops. By combining the experimentally known coalescence rate dependence on drop diameter with the independently determined dependence of the latter on the dispersed phase hold up, the breakup rate was found to depend on d2.

ISSN:0008-4034    

DOI:10.1002/cjce.5450510503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractNumerical solutions of the Naviet‐Stokes equation have been used to extend Kuwabara's zero voiticity cell model to flow past banks of circular and elliptical cylinders for Reynolds numbers up to 50 and for porosities between 0.4 and 0.8. Total drag coefficients are presented. The complete energy equation was also solved numerically for Prandtl numbers of 0.7 and 7. Good agreement between existing experimental results for heat transfer in banks of circular cylinders and the numerical solution was obtained. In the assemblage, the ratio of the total heat transfer to pressure drop was highest when the main flow was parallel to the major axes of the elliptical cylinders. In all cases considered, the ratio of the minor to the major axis was 0.

ISSN:0008-4034    

DOI:10.1002/cjce.5450510504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractThe distinctly different turbulent heat transfer characteristics of flocculated kaolin slurries are compared with nonflocculated coal slurries via modified J‐factor correlation forms for tubular exchangers. Both slurry types were statistically best‐fitted with the approximate solution Bingham plastic flow model in preference to the local shear power law. In addition, the first known turbulent slurry heat transfer cooling results are presented along with the heating results. No distinction was made between heating and cooling correlation forms because of a random scatter of experimental points.Experimental results were interpreted as followsA. Flocculated kaolin slurriesJH= (h/CpG) (C pμLe Bϕ/K1)2;3= 0.027(DVρ/μLeBϕ)0.211%ω<%ω Solids%w Solids<33.5%.Maximu

ISSN:0008-4034    

DOI:10.1002/cjce.5450510505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractA number of heat and mass transfer problems of chemical engineering interest involve the convective diffusion equation of the form\documentclass{article}\pagestyle{empty}\begin{document} \[u(x_2 )\frac{{\partial \theta }}{{\partial x_1 }} = \kappa \,\nabla ^2 \theta + G)x_1, x_2 )\] \end{document}where θ = θ(X1, X2). Exact solutions for such problems are developed in terms of well‐known functions which have been thoroughly studied in recent years. Several problems which have appeared in the literature, solved by completely numerical methods, are re‐examined and new problems are discussed and solved. The results of the present analysis are compared with those obtained by other methods where possible. The problem of axial diffusion of heat or mass is solved in terms of known functions.The present formulation is shown to be particularly useful in the analysis of conjugated boundary value problems, i. e. for problems involving heat or mass transfer across an interface where the interfacial boundary condition is not knowna prioribut is related to the temperature or concentration fields in the adjacent p

ISSN:0008-4034    

DOI:10.1002/cjce.5450510506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractThe partition of solids between stages in baffled fluidized beds has been studied. The bed, 9 ft tall and 11 in I. D., was divided into two or three stages by horizontal perforated plate baffles having open areas ranging from 11.5 to 34%. The spacing between baffles was varied from 1.5 to 3.5 ft. Four fluidized solids were studied and the velocity of the fluidizing air was varied between 0.2 and 2.5 ft/sec. A correlation was developed which enabled the solids holdup in each stage to be predicted.

ISSN:0008-4034    

DOI:10.1002/cjce.5450510507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractExperimental kinetic data in a form equivalent to concentration‐time trajectories (or the corresponding rates of reaction) may be decomposed into rate data for the individual chemical reaction steps defining a chemical reaction network. When kinetic models are fitted to each set of single‐step rate data, the resulting single‐step kinetic models may be combined to formulate an overall kinetic model for the network. Such network‐kinetic models may exhibit consistency with both the apparent chemistry and the observed rate be

ISSN:0008-4034    

DOI:10.1002/cjce.5450510508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractThe introduction of sulphonic groups to urea melamineformaldehyde resins has been shown to improve their performance as chlorine exchange resins for treatment of drinking and swimming pool waters. The preparation of resins containing a range of sulphonic content (UMFS resins) is described. Suspension polymerization produced resin beads suitable for use in fluidized beds. Scanning electron microscopy showed the resin structure to be macroreticular, porosity increasing with the sulphonic content in the formulation. Chlorination of water by fluidized beds of such resins showed that the activity increased with sulphonic content, steady state residual chlorine levels of 2 to 4 ppm being obtained with 0.5 or 1 mole sulphonic group per mole urea in the formulation.

ISSN:0008-4034    

DOI:10.1002/cjce.5450510509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY

摘要:

AbstractThe growth of a droplet of concentrated sulphuric acid suddenly exposed to water vapor was investigated. Droplet size and temperature as functions of time were obtained by numerical solution of droplet mass and energy balances. Inclusion of heat effects is thought to be an advance over previous studies of droplets of dilute acid which could be assumed to remain isothermal during the growth process. The results indicate that the growth process is completed in a few milliseconds for micron‐size droplets. The solutions presented are applicable to the continuum regime and the results are compared with experimental and calculated results of previous worker

ISSN:0008-4034    

DOI:10.1002/cjce.5450510510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1973

数据来源: WILEY