摘要:

AbstractThis paper is a survey of recent published works on the dynamic and steady state modeling of emulsion homo‐ and copolymerization in batch, semicontinuous, and continuous latex reactors. Contributions to our understanding of diffusion‐controlled termination and propagation reactions, molecular weight, long chain branching and crosslinking development, polymer particle nucleation, and of the dynamics of continuous emulsion polymerization are critically revie

ISSN:0001-1541    

DOI:10.1002/aic.690310602

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractThe diffusion coefficients of potassium chloride and sodium chloride were measured in concentrated, saturated, and supersaturated solutions at 25°C employing Gouy interferometry. The results indicate a maximum in the diffusivity vs. concentration curve near saturation followed by a rapid decline in diffusivity toward zero with increasing concentration in the supersaturated region. This behavior supports the idea that the diffusion coefficient approaches zero at the spinodal concentration. The data were successfully correlated by modifying an empirical activity coefficient equation (Robinson and Stokes, 1955) to account for molecular cluster effects and employing the calculated activity coefficients along with a predictive equation for diffusivity in electrolytes (Robinson and Stokes, 1955)

ISSN:0001-1541    

DOI:10.1002/aic.690310603

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractNew measurements are presented for film height and pressure drop for vertical gas‐liquid annular flows. Improved methods for predicting the film height and interfacial friction factor are developed for situations in which the liquid film flow rate is know

ISSN:0001-1541    

DOI:10.1002/aic.690310604

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractA mathematical model is developed for rapid hydropyrolysis of softening coal particles. It is aimed to represent previously measured effects of pressure and particle size on product yields. The model includes a global chemical reaction scheme combined with diffusional transport of hydrogen dependent on the transient physical properties of the coal. Model predictions are compared with experimental data in a companion paper.

ISSN:0001-1541    

DOI:10.1002/aic.690310605

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractThe mathematical model described in Part I is applied to predict CH4and tar yields in rapid hydropyrolysis of softening coal particles. Predicted effects of pressure and particle size agree with trends previously measured in a screen heater apparatus.

ISSN:0001-1541    

DOI:10.1002/aic.690310606

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractThe catalyzed direct reduction of lead sulfide with carbon and lime was investigated at several temperatures and under two different inert gas atmospheres. The catalyzed reduction kinetics were determined both with a nitrogen atmosphere and a helium‐rich helium‐nitrogen atmosphere. The reduction kinetics under the latter were decidedly superior to those under the former. The differences were interpreted in terms of faster diffusion rates in a helium medium and synergistic effects. The catalyst used was a ternay eutectic mixture (K, Li, Na)2CO3, which amounted to 2.5 wt. % of the PbS:4CaO:4C reaction mixt

ISSN:0001-1541    

DOI:10.1002/aic.690310607

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractResidues accumulating within the cavities of a small‐pore zeolite, isolated by extraction, are composed of a series of aromatics up to a distinct cutoff at pyrene. Similar analysis of partiall‐regenerated catalyst reveal pathways by which residue oxidation can occur and pathways by which these residues can participate during methanol decomposit

ISSN:0001-1541    

DOI:10.1002/aic.690310608

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractA transient mathematical model has been developed which describes the behavior of packed‐bed catalytic converters during warmup. Model predictions agree very well with the results of engine‐dynamometer experiments for three Pt‐alumina catalysts of widely different properties, thus demonstrating the validity of the

ISSN:0001-1541    

DOI:10.1002/aic.690310609

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractThe converter warmup model developed previously (Oh and Cavendish, 1985) has been used to simulate the performance of a packed‐bed converter during the cold‐start portion of vehicle emissions tests. Despite the highly transient converter inlet conditions, the model successfully predicts tailpipe mass emissions as a function of t

ISSN:0001-1541    

DOI:10.1002/aic.690310610

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractWhen a small bubble is driven through a liquid phase to a liquid‐gas interface, a thin liquid film forms between them and drains until an instability forms and coalescence occurs. Following Lin and Slattery (1982b), Chen et al. (1984) and Hahn et al. (1985) analyzed this process, neglecting the effects of electrostatic forces and of the surface viscosities. Here we extend their theory to include the effects of the surface viscosities. We employ a modification of the development by Barber and Hartland (1976; Flumerfelt et al., 1982) for a draining film bounded by parallel planes.For a large intermediate range of the surface viscosities, the coalescence time is a strong function of these parameters. Inclusion of the surface viscosities acts to moderate or even reverse trends previously established for the dependence of the coalescence time on the bubble radius, the viscosity of the film liquid, the interfacial tension, the strength of the London‐van der Waals forces, and the density difference between the two pha

ISSN:0001-1541    

DOI:10.1002/aic.690310611

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY