摘要:

AbstractSome practical methods of reducing tube side thermal resistance in process heat exchangers are discussed, both for clean surfaces and in the presence of water side fouling. Factors of importance in hard water scaling are outlined. Gains to be made by changes in velocity, tube geometry and surface area augmentation are explored.

ISSN:0008-4034    

DOI:10.1002/cjce.5450580501

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

年代:1980

数据来源: WILEY

摘要:

AbstractA simple correlation has been developed to predict the expansion of a liquid fluidized bed, consisting of particles varying in size and/or density, which is of the following form:\documentclass{article}\pagestyle{empty}\begin{document}$$ L_c = 1.27W/|\rho _H D^2 (1 ‐ 1.762U + 0.95U^2 )| $$\end{document}The relationship is valid over the voidage range from ϵmfto ϵr= 0.96 and gives directly the expanded bed height Lewithout the determination of the bed porosity ϵeas in existing correlations. The size and density of the solids varied from 30/40 to 72/80 mesh BSS and from 1.67 to 4.33 gm/cm3respectively while the range of Retvaried from 0.12 to 43.66. The standard deviation for measurements on unicomponent and multicomponent systems has been calculated to be 11.5% and 19.6% respectively at an L/D ratio of 2

ISSN:0008-4034    

DOI:10.1002/cjce.5450580502

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe hydrodynamics of a Newtonian fluid entrained from a stagnant pool by a rotating, partially immersed horizontal cylinder is considered. A numerical solution, based on the Galerkin method of weighted residuals, predicts the film thickness variation over the cylinder surface. The results are compared with experimental measurements and theoretical predictions available in literature. The comparison with the experimental data is good, especially for high capillary numbers. This supports the claim that inertia effects are better depicted in a nonlinear treatment of the problem. The computational procedure applied is not complicated, and may be used for industrial predictions.

ISSN:0008-4034    

DOI:10.1002/cjce.5450580503

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe results of a laboratory wind‐wave tank study are reported in which the rate of mass transfer of a tracer (phenol) from a synthetic oil slick to the underlying water was measured at wind speeds from 0 to 9 m/s. Estimates were made of the mass transfer coefficients in the oil and water phases at the oil‐water interface. The results indicate that the rate of hydrocarbon dissolution from a slick is controlled by the water phase mass transfer coefficient which is usually less than 1 cm/h. Whereas mass transfer coefficients at air‐water interfaces show a marked increase at wind speeds of approximately 3 m/s due to wave formation, when oil is present its damping effect delays this transition to approximately 7 m/s. It can be inferred that (i) dissolution is considerably slower than evaporation for reasonably volatile compounds, (ii) dissolution will have a negligible effect on slick composition, (iii) the concentrations of soluble hydrocarbons established in the water column under the slick by direct dissolution are small and unlikely to result in significant toxicity, and (iv) that the dominant mechanism of transfer of soluble hydrocarbons into the water column is probably from dissolution of dispersed oil part

ISSN:0008-4034    

DOI:10.1002/cjce.5450580504

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

年代:1980

数据来源: WILEY

摘要:

AbstractSeries of synthetic neutral surfactants have been used to break emulsions of heavy oil, water and clay. The degree of de‐emulsification was found to correlate with the hydrophilic‐lipophilic balance (HLB) of the surfactant. The most effective agents for de‐watering had HLB values between either 4 and 6 or 13 and 15. For clay removal, the most useful surfactants had HLB values above 20. Surfactants between 5 and 8 were also effective for removing clay, but the material released had appreciably more oil adhering than that removed by the higher HLB compounds. Other surfactant parameters such as surface tension, interfacial tension against hexadecane and spreading tension were unrelated to de‐emulsifying

ISSN:0008-4034    

DOI:10.1002/cjce.5450580505

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

年代:1980

数据来源: WILEY

摘要:

AbstractA solvent extraction procedure is presented for separating large quantities of bitumen to be used in laboratory experiments. The effectiveness of various solvents is discussed. Data are presented on the properties of extracted bitumen, the unextracted residue and the light ends lost during solvent removal. The effect of bitumen contact with oxygen is also discussed.

ISSN:0008-4034    

DOI:10.1002/cjce.5450580506

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe oxidation of propylene over a silver oxide containing sodium chloride and sodium hydrogensulfate has been studied by using a transient response method at temperatures ranging from 150 to 175°C. An overshoot behavior for the transient response of propylene oxide indicates the mechanism of Eley‐Rideal type with a rapid desorption of propylene oxide and a slow regeneration of surface oxygen. The activation energy estimated at the transient state was 58.6 kJ/mol.A characteristic S‐shape mode for the transient response of carbon dioxide reveals the presence of a stable intermediate (In). The (In) can produce equimolar amounts of H2O and CO2by the reaction with oxygen without producing propylene oxide, indicating that the ratio of C:H in the structure of (In) is 1:2. The amount of (In) estimated under the steady state of reaction is a linear relation to the rate of CO2formation. The estimated apparent rate constant for the formation of CO2is in good agreement with that for (In) decomposition estimated from the transient response curves of (In) decomposition. From this agreement, it is concluded that the (In) is a reaction intermediate through which carbon dioxide and water are prod

ISSN:0008-4034    

DOI:10.1002/cjce.5450580507

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe rates of absorption of oxygen into aqueous cuprous chloride solutions containing hydrochloric acid were measured at 15, 25 and 35°C using a baffled agitated vessel operated batchwise and the experimental results were analyzed with the chemical absorption theory.The reaction between oxygen and cuprous chloride was found to be second order, i.e. first order with respect to oxygen and CuCl2−ion which is the actual reactive species in aqueous cuprous chloride solutions containing hydrochloric acid. The reaction rate constants were calculated and correlated as a function of temperatu

ISSN:0008-4034    

DOI:10.1002/cjce.5450580508

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to investigate the effect of increasing chromium concentration on the activity and physical properties of chromia/alumina catalysts. The catalysts were prepared by impregnating η‐alumina support in various concentrations of chromic acid solution and were finally calcined in air.A variety of physical‐chemical properties of the catalysts were studied. These included BET surface area, pore volume, metal concentration, x‐ray diffraction studies, oxidation states using EPR, surface oxidation (excess oxygen) measurement by iodometric titration, metal area measurement and crystallite size determination. Decomposition of hydrogen peroxide was used to determine the activity of various catalysts.A correlation of catalytic activity with crystallite size indicated that both, activity per unit chromia area and activity per g of catalyst were maximum at a crystallite size of 3.7 mm. Also, the activity per unit chromia area is maximum when chromia is deposited 3‐4 layers thick.In contradiction to the view put forth in the literature, this study indicates (on the basis of excess oxygen and chemisorption measurement) that not only is all of the top chromium oxidized to Cr6but that the oxidation also takes place in the sub‐surfac

ISSN:0008-4034    

DOI:10.1002/cjce.5450580509

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

年代:1980

数据来源: WILEY

摘要:

AbstractStatistical multiresponse techniques for the design and analysis of experiments were used in conjunction with an integral isothermal staged tubular reactor to identify the reaction network for the oxidation of o‐xylene over a V2O3/K2SO4/silica catalyst. Following a five stage strategy a precise quantitative description of the reaction network in terms of the multiresponse form of the steady state adsorption model was obtained. The use of mixed feeds was found to improve the precision of rate parameters associated with later steps in the reaction network and also to reduce correlations among estimates of the rate parameter

ISSN:0008-4034    

DOI:10.1002/cjce.5450580510

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

年代:1980

数据来源: WILEY