摘要:

AbstractRates of pipewall oxygen mass transfer in a 39 mm ID vertical pipe carrying an aqueous slurry containing 20 vol% 30‐50 mesh sand have been determined electrochemically with twin in‐line flow cells, one containing a mild steel specimen previously roughened by erosion‐corrosion and the other a smooth specimen. Measurements were also made without the solids present.The three‐dimensional rough surface, with roughness height approximately 0.2 mm, and pitch/height in the range 5 to 10, resulted in mass transfer enhancement up to 100%, in both the slurry and the solution, with the maximum effect occurring at the dimensionless roughness height

ISSN:0008-4034    

DOI:10.1002/cjce.5450660111

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

年代:1988

数据来源: WILEY

摘要:

AbstractOxygen transfer into Newtonian and non‐Newtonian fluids was studied in stirred tank vessels of 0.0018, 0.006 and 0.036 m3operating volumes. Emphasis was given to the rheological effects of the pseudoplastic medium on the volumetric oxygen transfer coefficient,KLa. Results indicate thatKLais a strong function of gassed power input per unit volume (Pg/V) for the Newtonian fluid, but a weak function ofPg/Vfor the non‐Newtonian fluid, and a strong function of superficial gas velocity (Vs) for both fluids for paddle‐type impellers.KLais found to decrease rapidly with an increase in apparent viscosity for values of μagreater than 2.0 Pa · s. In addition to various correlations, a dimen‐sionless correlation including the impeller Reynolds number, impeller Weber number, and the aeration number is presented for the prediction ofKLain a gas‐liquid non‐New

ISSN:0008-4034    

DOI:10.1002/cjce.5450660112

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

年代:1988

数据来源: WILEY

摘要:

AbstractDans un complexe de fabrication d'aluminium, le procédé de cuisson des anodes donne lieu à une libération importante de matières volatiles combustibles. Le présent travail vise à mieux comprendre la cinétique de dégagement de ces substances. À cette fin, un dispositif thermogravimétrique de grandes dimensions a été mis au point de façon à pouvoir simuler le mieux possible l'environnement industriel. Des échantillons de deux masses distinctes ont été soumis à la pyrolyse à différents régimes de chauffage. La perte de poids et les concentrations des gaz dégagés ont été enregistrées tout au long de la montée en température. Les résultats cinétiques sont rapportés pour le méthane, l'hydrogène et le goudron. L'ordre de réaction ne varie pas avec la vitesse de chauffage alors que l'énergie d'activation et le facteur pré‐exponentiel augmentent. De plus, pour les grosseurs d'échantillons étudiés, il a été trouvé que la masse du solide n'influ

ISSN:0008-4034    

DOI:10.1002/cjce.5450660113

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

年代:1988

数据来源: WILEY

摘要:

AbstractToxic effects of inhibitors on microbial growth in the activated sludge process were demonstrated by a kinetic model. The effects of pH and biomass concentration on the degree of inhibition were described. The applicability of the kinetic model to describe the inhibitory effects with respect to various growth measuring parameters like respiration rate, ATP analysis, first and zero order reaction rates were illustrated. The inhibitory effects of heavy metals on the nitrification and denitrification processes were established. Experimental data from other investigations were used to prove the applicability of the model.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660114

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

年代:1988

数据来源: WILEY

摘要:

AbstractAs part of the UDES‐S solvolytic approach to wood fractionation and liquefaction, a pretreatment stage has been developed using a fed batch technique to produce high solids content slurries. By using a combination of temperature and shear stress across homogenizing valves, wood flour slurries ofPopulusspp having concentrations of 20‐32% by weight in both paraffin oil and ethylene glycol have been produced. Optical and scanning electron microscopy have shown that the recirculation loop and homogenizing valve cause structural degradation, defibration and defibrillation of the original particles as well as partial solubilization of the wood components. The maximum wood flour concentration, attainable before plugging was observed in the small scale system used, was just below 36% by weight. High concentration slurries are a prerequisite in order to obtain realistic reactor space velocities in biomass liquefaction proces

ISSN:0008-4034    

DOI:10.1002/cjce.5450660115

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe UDES‐S liquefaction process treats concentrated pastes (20% of initially present solids) of finely divided (dp<0.5 mm) lignocellulosics in organo‐solvolytic media by means of thermo‐mechanical action in homogenizing valves.The work described in this paper was carried out withPopulus Deltoidesin a process development unit capable of processing up to 4 kg of dry wood per hour. The model solvents used were creosote oil and ethylene glycol, which represent solvents that could be derived from the process or its products. Liquefaction mechanisms depend upon the solvent‐substrate interaction: with creosote oil, pyrolysis mechanisms predominate and lead to integral liquefaction of the wood while with ethylene glycol only fractional liquefaction was possible, apparently as a result of a complex formation between ethylene glycol and cellulose which protects the chain polymeric from being solu

ISSN:0008-4034    

DOI:10.1002/cjce.5450660116

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

年代:1988

数据来源: WILEY

摘要:

AbstractScanning electron microscopy shows that the liquefaction of poplar sticks (6.35 mm square cross section) by aqueous pyrolysis first involves the surface disruption of the middle lamella. The latter and cell walls then fuse, and the flowing matrix then engulfs the cells. At surface temperatures of 280°C spherical structures appearwithinthe stick, particularly on vessel walls. Flowing matrix fills irregular cavities within the stick and gas or vapour bubbles are formed. The spherical structures are insoluble in ether, which dissolves monomeric material, but are disrupted by chloroform which dissolves oligomers. Acetone which dissolves higher molecular weight material, removes the spheres

ISSN:0008-4034    

DOI:10.1002/cjce.5450660117

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

年代:1988

数据来源: WILEY

摘要:

AbstractHeat of mixing for ammonium chloride in liquid ammonia at 25°C was determined in the concentration range 0‐50 wt% NH4Cl. It was calculated from the differential heat of solution observed in this work and the differential heat of dilution estimated from activities of solvent. A twin isoperibol calorimeter consisting of two stainless Dewar vessels was used at a relatively high pressure (up to 1.5 MPa). The accuracy of this calorimetry was examined by measuring the heat of solution for tris‐(hydroxymethyl)aminomethane(THAM) in 0.1 kmol/m3HCl at 25°C, and satisfactory agreement within 1.1% between experimental and literature value was obtained. The reproducibility for the experiment was within

ISSN:0008-4034    

DOI:10.1002/cjce.5450660118

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

年代:1988

数据来源: WILEY

摘要:

AbstractData on vapor‐liquid equilibrium and enthalpy of mixingHEare, obtained for the mixture 1, 3 dioxolane‐methylcyclohexane at 313.15 K (40.0°C). Correlation of the data is given by using Redlich‐Kister expressions and the excess functionsGE=RT(X1In γ1+X2In γ2) andTSE=HE‐GEare thereby calculated. A comparison is made between this mixture and those formed by 1, 3 dioxolane with cyclohexanol and cyc

ISSN:0008-4034    

DOI:10.1002/cjce.5450660119

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis article reports equilibrium data for the binary liquid‐liquid system water + methyl propyl ketone at temperatures in the range 20‐55°C, together with solubilities and equilibrium compositions of the ternary system water + acetic acid + methyl propyl ketone at 25, 35, 45 and 55°C. NRTL and UNIQUAC equations have been fitted to the experimental data for the ternary system, which are likewise compared with the values predicted by the group contribution method U

ISSN:0008-4034    

DOI:10.1002/cjce.5450660120

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

年代:1988

数据来源: WILEY