ISSN:0008-4034    

DOI:10.1002/cjce.5450600301

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

年代:1982

数据来源: WILEY

摘要:

AbstractMica platelets were left untreated or coated with glycerol at 1%. 5% or 10% by mass, and extruded in carboxyl‐modified polypropylene at volume fractions up to 20%, and at temperatures between 468 and 528 K. At a shear rate of 10 s and at 500 K, the Einstein coefficient decreased from 2.1 when glycerol was added. The flow behavior index, ranging between 0.57 and 0.45, decreased when the shear rate or amount of mica or of glycerol was increased, while the opposite occurred when the temperature was raised. In the solid state, the tensile modulus increased, but the tensile strength was degrade

ISSN:0008-4034    

DOI:10.1002/cjce.5450600302

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

年代:1982

数据来源: WILEY

摘要:

AbstractStratified slurries flowing through horizontal venturi meters are shown to have discharge coefficients higher than values for homogeneous fluids. This effect increases with slurry concentration and decreases as the velocity increases. Predictions using a two‐layer model are qualitatively reasonable but inadequate knowledge of the effect of fluid lift forces makes quantitative prediction difficul

ISSN:0008-4034    

DOI:10.1002/cjce.5450600303

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

年代:1982

数据来源: WILEY

摘要:

AbstractCorrelations for the pressure drop, solids concentration and mean holding time of the solids in multistage fluidisation have been presented based on the experimental data of the present study and that available in literature covering a wide range in process variables.

ISSN:0008-4034    

DOI:10.1002/cjce.5450600304

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe hydrodynamic and mass transfer characteristics of bubble and packed bubble columns with downcomer were investigated. The contactor consisted of two concentric columns of 0.11 and 0.2 m i.d., with the annulus acting as the downcomer. The packing used in this investigation was standard 16 mm stainless steel Pall rings. The superficial gas and liquid velocities,VGandVL, were varied from 0.01 to 0.09 and 1 × 10−3to 8.8 × 10−3m s−1respectively.Two flow patterns, namely the bubble and pulse flows were observed in the packed bubble column with downcomer, as shown by a flow map.The liquid circulation velocity in both the contactors was observed to be constant throughout the ranges ofVGandVLcovered in this work. The effect of liquid viscosity (0.8 to 9.5 mPa ṁ s) and surface tension (45 to 72 mN m−1) on the flow pattern, liquid circulation, gas hold‐up and pressure drop was investigated. The pressure drop characteristics across the two contactors have been compared with those across a bubble column.Values of the effective interfacial area, a, and the volumetric mass transfer coefficient,kLa, were measured by using chemical methods. Values of a as high as 180 and 700 m−1andkLa as high as 0.075 and 0.22 s−1, in the bubble and packed bubble columns with downcomer, respectively, were obtained. The values of true liquid‐side mass transfer coefficient,kL, were found to be independent of VGand were of the order of 5.5 × 10−4and 3.5 × 10−4m s−1, respecti

ISSN:0008-4034    

DOI:10.1002/cjce.5450600305

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe dynamics of adsorption columns with the presence of bacterial activity was studied analytically and experimentally. The bacterial activity results in the formation of growing microbial films outside adsorbents. Equations describing the interaction between adsorption and bacterial growth were formulated and algorithms for their solutions developed. Experiments relating to the removal of valeric acid from aqueous solutions with granular carbon in the presence of denitrifying bacteria were performed to substantiate the analysis.

ISSN:0008-4034    

DOI:10.1002/cjce.5450600306

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe study of the adsorption of an acid dye (AB‐80) and of a basic dye (BR‐22) has been carried out on charred woollen fibres, with a view to using that industrial waste material in the treatment of liquid effluents. The authors have first studied the dye diffusion; the diffusion of AB‐80 appeared much slower than that of BR‐22, due to the steric cumbersomeness of the AB‐80 molecule. As a result, the temperature effect on the diffusion, owing to its influence on the dye aggregation, was clearly more pronounced for AB‐80 than for BR‐22; that fact was confirmed by the determination of adsorption isotherms at different temperatures. Under favourable conditions, the curves indicated satisfactory adsorption values; as they were cither of type H (AB‐80) or L (Br‐22), they also indicated the efficiency of the aforesaid fibres in the treatment of slightly‐concentrated effluents. The above finding has been verified by a column treatment of an AB‐80 solution; it then showed the very strong influence of the contact time as well as a wall effect on the effluent purification. In the study conclusion, the results obtained in the treatment of an industrial effluent in a stirred

ISSN:0008-4034    

DOI:10.1002/cjce.5450600307

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe effect of the dynamics of the mixing process in mechanically stirred bioreactors upon their performance has been investigated by using a circulation‐model for flow of fluid and a two‐environment‐model to account for the extent of micromixing in the vessel. With the help of an empirical kinetic model to depict the oxidative and the fermentative growth of bakers' yeast, experimentally observed effects of initial sugar concentrations upon critical dilution rates in continuous cultures of this system could be explained. Effect of different scales of operation upon productivities of fed‐batch cultures of bakers' yeast could also be satisfactorily predicted. A discrete simulation procedure was found to be a convenient tool in coupling the two‐environment circulation‐model of mixing with kinetics of microbia

ISSN:0008-4034    

DOI:10.1002/cjce.5450600308

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

年代:1982

数据来源: WILEY

摘要:

AbstractA case study is presented and thoroughly discussed to show that through rigorous application of statistical criteria it is possible to: (a) unambiguously identity the effect of each catalyst tested upon overall yields; (b) determine the extent of the effect on individual product yields and (c) classify the catalysts on a performance basis.The study focuses on the pyrolysis of naturally occuring peat doped with small amounts of finely dispersed metals (K. Fe, Co and Ni) introduced by impregnation with their nitrate salts. The pyrolysis has been conducted on the air‐dry material under reduced pressure conditions at a heating rate of 10°C/min up to a temperature of 925°C.The statistical analysis resulted in rejection of the initial underlying hypothesis which considered that the metallic additives will exert an influence on the overall peat tar yield and composition. Presence of important amounts of silica (as ash) might have been responsible for the lack of catalytic effects observed. The work stresses the usefulness of repetitive runs to determine the inherent experimental error when conducting catalyst screening on real substra

ISSN:0008-4034    

DOI:10.1002/cjce.5450600309

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

年代:1982

数据来源: WILEY

摘要:

AbstractExperimental leaching runs were carried out in a continuous concurrent laboratory size bubble column 5.2 cm in internal diameter and 2.90 m tall. The system studied was the dissolution of a synthetic covellite (CuS) in ammoniacal solution in the presence of pure oxygen. Behaviour of the column with respect to gas holdup and solids concentration profiles was measured without reaction by using nitrogen in place of oxygen. Gas holdup values were in agreement with literature results. However, solids concentration profiles for the mixed particle size solid used were of a more complex nature than those obtained for uniformly sized solids.Conversions obtained at various temperatures and gas and liquid velocities were analyzed in terms of the estimated rates of the individual rate processes occurring. From these results, gas absorption rate was clearly the controlling mechanism at high temperatures, and surface chemical reaction rate was controlling at low temperatures. Hence, the rate controlling steps can be identified in bubble column reactors from currently available literature correlations, together with independent kinetic measurements.

ISSN:0008-4034    

DOI:10.1002/cjce.5450600310

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

年代:1982

数据来源: WILEY