摘要:

AbstractWe hereby submit three different numerical methods for the solution of the multicomponent distillation model for two partially immiscible liquids. A procedure to define the real number of phases present on each stage has been developed. The proposed Newton‐Raphson method allows efficient solution of problems with a large selection of the unknowns and the specification equation

ISSN:0001-1541    

DOI:10.1002/aic.690270602

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractBased on terLinden's (A. J. terLinden, “Investigations into Cyclone Dust Collectors,” IME Proc., 160, 233, 1949) experimental observations, a three‐region model is proposed for the fluid flow in a cyclone. Within each region, turbulence is assumed to promote mixing of the suspended particles. Incorporation of this mixing concept into the three‐region model allows an analytic expression for the collection efficiency of the cyclone to be developed.The theoretical result is compared with data obtained in the high temperature, high pressure exhaust from a pressurized fluidized bed co

ISSN:0001-1541    

DOI:10.1002/aic.690270603

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractThe use of dynamic (tracer) methods for the evaluation of liquid‐solid contacting and holdup in trickle‐bed reactors is illustrated. It is shown that both the fraction of external catalyst area wetted and the fraction of total catalyst wetted by liquid can be obtained. External contacting efficiency and dynamic liquid saturation are correlated in terms of the appropriate dimensionless groups over the range of variables typical for trickle‐flow operation. The relationship between catalyst contacting efficiency and catalyst utilization is out

ISSN:0001-1541    

DOI:10.1002/aic.690270604

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractA new cascade configuration for the continuous membrane fractionation of solutes having similar permeabilities is proposed. In this scheme, solute selectivity is amplified by combining a concentrator and several mass exchangers (e.g., a reverse osmosis unit and hollow fiber dialyzers) to achieve a desired degree of separation. Separation efficiency of the new cascade is compared with that of a conventional counter‐current cascad

ISSN:0001-1541    

DOI:10.1002/aic.690270605

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractA tube with sinusoidal axial variations in diameter has been used as a first step toward modeling the flow channels of a porous medium in such a way that appreciable Lagrangian unsteadiness is present. Experiments with dilute aqueous solutions of a polyacrylamide (Dow Separan AP‐30) show that the Lagrangian unsteadiness gives rise to an increase in resistance to flow through the sinusoidal channel relative to that predicted for a purely viscous fluid. The increase in pressure drop can occur as a consequence of fluid elasticity, without any observable secondary flow. At sufficiently high flow rates, secondary flow appear

ISSN:0001-1541    

DOI:10.1002/aic.690270606

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractA series of seven coals were oxidized in a fixed bed reactor to determine the controlling reaction regimes during mild coal oxidation. The effects of coal porosity and particle size, reactor temperature, and oxygen partial pressure were evaluated. The results show that coal‐oxygen reactions are controlled by the rate of internal gaseous diffusion for most coals, and by the rate of chemical reaction for the most porous coal of the set tested. Particle size effects also suggest internal diffusional control. Determinations of cumulative oxygen deposition indicate that surface areas several orders of magnitude greater than the superficial surface can participate in oxidation reactions, putting in doubt the applicability of the model previously derived by Kam et al. (1976a) for external mass transfer contro

ISSN:0001-1541    

DOI:10.1002/aic.690270607

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractThe Isotherm Migration Method of numerically analyzing conduction with phase change is modified to handle surface and external resistances, appearance, and propagation of successive fronts into slabs of composite material of one or more constituents finely dispersed in a matrix, different components transforming at different temperatures. Procedures are developed for selecting temperature intervals between isotherms, initially locating isotherms by means of analytical approximations to the earliest stages, and thereafter inserting and removing isotherms as appropriate, particularly when each component gives rise to a separate front.

ISSN:0001-1541    

DOI:10.1002/aic.690270608

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractMathematical models have been developed for the design of bubble column slurry reactors, wherein the solids take part in the reaction and follow the shrinking core model. The cases of liquid film control, ash diffusion control, and chemical reaction control have been analyzed. Experiments were performed in a 22.2 mm i.d. continuous cocurrent bubble column slurry reactor for the removal of pyritic sulfur by oxidation from aqueous slurries of Upper Freeport, Lower Freeport, Kentucky No. 9, and Pittsburgh seam coals, in the temperature range of 430‐480°K at 6.8 MPa total pressure. The theoretical predictions are found to be in good agreement with experimental resul

ISSN:0001-1541    

DOI:10.1002/aic.690270609

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractA novel experimental setup allowed both the kinetics of the thermal cracking of ethane and of the coke formation to be studied over a temperature range extending from 750 to 870°C. The overall kinetics of ethane disappearance are in excellent agreement with previously reported pilot results. Coking rates are initially high but rapidly decrease to reach an asymptotic value. The initial product distribution also differs from the asymptotic product distribution. A kinetic model for the coking is derived from the experiments and used in conjunction with a set of conservation equations for the simulation of industrial ethane cracking. The predicted run length, thickness of the coke layer and evolution of the tubeskin temperatures are in agreement with industrial observations

ISSN:0001-1541    

DOI:10.1002/aic.690270610

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY

摘要:

AbstractEffects of molecular size and configuration on hindered diffusion were examined by measuring diffusion of two series of uncharged macromolecules through track‐etch membranes with uniform and well‐defined pore geometry. At any given Stokes‐Einstein radius, diffusivities in small pores were lower for ficoll (crosslinked structure) than for dextran (more nearly linear struc

ISSN:0001-1541    

DOI:10.1002/aic.690270611

出版商:American Institute of Chemical Engineers    

年代:1981

数据来源: WILEY