摘要:

AbstractAn experimental method was developed for characterizing time‐dependent slurries of elongated particles in a coaxial cylinder viscometer which has a wide gap between the inner rotating cylinder and the stationary cup. A model slurry system was studied; it consisted of a dispersed phase of regularly sized nylon fibres and a dispersing medium of an aqueous solution of polyethylene glycol with dextrose and sodium chloride, each of whose effects on the time‐dependent nature of the slurry could be examined.It was found that only a part of the gap between the cylinders of the viscometer flows under shear, and that the thickness of the flowing layer increases with time and approaches an equilibrium value.An empirical reaction‐rate type model was constructed for the time‐variation of the thickness of the flowing layer. A second order‐zero order reversible reaction model fitted the experimental data well. The fitting parameters of the model were correlated with slurry

ISSN:0008-4034    

DOI:10.1002/cjce.5450570201

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

年代:1979

数据来源: WILEY

摘要:

AbstractViscosity data of an aluminum soap solution, a polyisobutylene solution, a polyacrylamide solution, and ten polystyrene solutions have been analysed using two rheological models: the Carreau model A and the Ellis model. The model parameters were obtained by non‐linear regression. The importance of the zero‐shear viscosity for design purposes is illustrated by observing the appearance of a master curve in the representation of the dimensionless viscosity versus the product of the zero‐shear viscosity by the shear rate. A linear relation is shown to exist between the logarithm of the zero‐shear viscosity and the polymer concentration. It is asserted that either model should replace advantageously the commonly used power‐law e

ISSN:0008-4034    

DOI:10.1002/cjce.5450570202

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

年代:1979

数据来源: WILEY

摘要:

AbstractA correlation is proposed for prediction of mean drop size in agitated vessels in the two major hydrodynamic regimes of importance as observed in this study covering a wide range of holdup from 0.01 to 0.5 and impeller Weber numbers from 35–200,00

ISSN:0008-4034    

DOI:10.1002/cjce.5450570203

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

年代:1979

数据来源: WILEY

摘要:

AbstractNew data have been reported on the absorption of oxygen by aqueous sodium sulphite solutions with cobalt sulphate as catalyst at 30°C. It is observed that the absorption rate increases up to a critical sulphite concentration beyond which the absorption rate becomes constant and this critical concentration varies with the catalyst concentration. The order of reaction with respect to sulphite and oxygen in the constant absorption rate regime was found to be zero and two respectively. The absorption rate is affected by the total ionic strength (sulphite and sulphate) in addition to the effect of pH and catalyst concentraion. The reported data were also analysed to ascertain the effect of temperature and a relationship has been proposed for prediction of the second order reaction rate constant

ISSN:0008-4034    

DOI:10.1002/cjce.5450570204

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe flooding and axial mixing characteristics of a 15 cm diameter reciprocating plate extraction column with six different plate arrangements handling kerosene dispersed in water are reported. A general correlation for flooding in the emulsion flow regime is developed and applied to the present results and to published data on other columns and systems. Under certain conditions of flow and agitation, the axial mixing is very high because of circulation, but it can be reduced by including baffles in the plate stack.

ISSN:0008-4034    

DOI:10.1002/cjce.5450570205

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

年代:1979

数据来源: WILEY

摘要:

AbstractA kinetic study of the dehydrogenation of ethanol to acetaldehyde on an unsupported catalyst of base composition CuO – Cr2O3was carried out in an isothermal reactor fed with ethanol 95% vol. in the temperature range 225–285°C with space velocities 1.5–7.5 LHSV at atmospheric pressure.The mechanism which was found suitable to describe the reaction was that of surface adsorption on dual sites.Taking into account interphase and intraphase diffusion, the observed conversions of ethanol were reconstructed with a standard error below 10%, thus confirming the validity of the physical assum

ISSN:0008-4034    

DOI:10.1002/cjce.5450570206

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe oxidation of SO2was carried out over an American Cyanamid V2O5catalyst in an insulated integral reactor without significant interparticle resistances under the following conditions: 10 percent SO2‐air feed, feed temperatures in the range of 430°C to 590°C, 108 kPa pressure, and entrance temperatures of the gases in the annular heat exchanger from 400°C to 450°C, with one set of conversions being obtained without annular air flow. Gas analysis was accomplished by the oxidation of SO2to SO3with potassium permanganate. The method was fully tested before adoption. Final conversions in the range of 5 to 60 percent were observed. A hysteresis loop was found in the plane of outlet conversion versus the average feed temperature. The multiplicity is possibly stable but probably decays with the time constants in the order of days which is evident from the transient data that were obtained. A one dimensional model was able to correlate the conversion data through the Arrhenius rate parameters in the Boreskov‐Sokolova(8)rate expression which changed from A = 1.92 × 107m3/(s·kg) and E = 151 MJ/kmol to A = 0.344 m3/(s·kg) and E = 33.5 MJ/kmol at a calculated temperature at the surface of the catalyst of 517°C. Similar behavior has been observed in other studies concerned with basic kinetic studies over catalyst pellets. The analogy between the behavior of the catalyst pellets and the behavior of the integral reactor can thus be fully drawn with respect to hysteresis and rate disc

ISSN:0008-4034    

DOI:10.1002/cjce.5450570207

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

年代:1979

数据来源: WILEY

摘要:

AbstractA study was conducted on the oxidation of CO over an industrial potassium‐promoted V2O5catalyst in order to study the influence of He, Ar, Kr, SF6and C4F8diluents on the reaction rate. A differential flow reactor was used between 400° and 440°C with partial pressures of CO2, O2and diluents varied from approximately 7 to 150 kPa. All the diluents inhibited the reaction rate to varying degrees. Experiments were also performed in which one diluent gas was displaced by another in the reaction mixture. These experiments indicated that the diluents could be arranged in the following increasing order of sorptive interaction with the catalyst:HeorAr

ISSN:0008-4034    

DOI:10.1002/cjce.5450570208

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe exchange of CI−ion between dilute aqueous solutions of hydrochloric acid and the ion exchange resin IRA‐425 in fluidized beds was studied in a laboratory size column. Analysis of the experimental data showed that axial mixing of particles in deep beds was incomplete and also that packed and fluidized bed break‐through curves were similar. A model is proposed describing the bed as a series of mixing stages for solids with axially dispersed flow of liquid. Data are presented in support of such a concept.An empirical method is proposed for prediction of the break‐through curves at various operating conditions, requiring only a very limited amount of experime

ISSN:0008-4034    

DOI:10.1002/cjce.5450570209

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

年代:1979

数据来源: WILEY

摘要:

AbstractA grid model including thermal effects is proposed. The aim is the simulation of a fluidized catalytic cracking regenerator similar to the industrial unit of Destileria La Plata, YPF, Argentina.It is demonstrated that a simple C.S.T.R. model without bypass of gas feed entering the bed provides a good approach for representing the fluidized bed including the grid region.In addition, by means of the C.S.T.R. model, it is shown that there exist two characteristic operating regions: a zone where (Coo– Co) depends on the initial coke concentration and a zone where (Coo– Cc) is controlled by oxygen sup

ISSN:0008-4034    

DOI:10.1002/cjce.5450570210

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

年代:1979

数据来源: WILEY