摘要:

AbstractPrevious attempts to model the effect of deposition on removal efficiency in deep‐bed filtration have relied heavily on the determination of empirical parameters even for monosized suspensions. A newly developed mathematical model not only significantly reduces this reliance, but takes full account of the polydispersity of suspensions. The results of eight runs on an experimental filter are compraed with the predictions of the mathematical model. Qualitative agreement is good; quantitative agreement is fai

ISSN:0001-1541    

DOI:10.1002/aic.690331102

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractIt is shown that the solubility of organic solids in binary mixtures of partially miscible liquids is singular at the immiscibility critical point. The theoretically predicted maximum of solubility in the vicinity of the critical point is found experimentally. The effect is similar to the phenomenon observed near the gas‐liquid critical point. The similarity of these two critical phenomena may have interesting technical applications and may provide guidelines for identifying promising new solvents for separation processe

ISSN:0001-1541    

DOI:10.1002/aic.690331103

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractA method for solving the problem of heat exchanger network synthesis in chemical process plants is presented based on the use of the out‐of‐kilter algorithm. The method represents an extension of previous approaches based on network flow problem formulations. A new approach to overcome the constraints in forbidden‐match problems, termed the dual stream approach, has been developed based on the use of a stream as both a hot and a cold stream. This approach results in considerable savings in utility costs in certain forbidden‐match problems. An algorithm to deal with heating or cooling utilities that undergo temperature changes, termed non‐point‐temperature utilities, is presented using the transshipment model. The new algorithm determines the utility mass flow rates and pinch points

ISSN:0001-1541    

DOI:10.1002/aic.690331104

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractThe diffusional processes that occur when oil contacts an aqueous surfactant solution have been investigated. These are pertinent to enhanced oil recovery by surfactant flooding and to detergency in certain systems. The theory of diffusion paths was used to solve the diffusion equations for a model pseudoternary system. Although detailed comparison with experimental results was not possible due to a lack of necessary data, calculated diffusion paths and interface velocities were found to be useful for explaining various phenomena observed experimentally in an oil recovery system.Because the surfactant “solutions” studied commonly exist as dispersions of liquid crystal, extension of the theory to allow for initial compositions in two‐phase regions was carried out. Also novel was investigation of the effect of the three‐phase regions that occur in these systems on the position and shape of calculated diffusio

ISSN:0001-1541    

DOI:10.1002/aic.690331105

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractA simple latticelike random contact point model is presented to correlate and predict second virial (or pair interaction) coefficients of thermodynamic quantities in dilute solutions. With this model it is possible to correlate pair interaction coefficients in different solvents with one equation and a single set of group interaction parameters. Enthalpic pair interaction coefficients of alkanes and alkanols dissolved in ten different alkan‐1‐ols and water, and of amides dissolved in N,N‐dimethylformamide, N‐methylformamide, and water are discussed in terms of the model. Corresponding group interaction parameters in water, alkan‐1‐ols, and amides are found to be equal within experimental error. When applied to aqueous solutions, the model yields the empirical equations of Savage and Wood, which are thus given some theoretical basis. The model also provides values of the higher interaction coefficients on the basis of the

ISSN:0001-1541    

DOI:10.1002/aic.690331106

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractThere is considerable economic incentive to convert methane into formaldehyde, which is used in the manufacture of insulating materials and adhesives. This paper discusses the kinetics of a one‐step oxidation of methane with molecular oxygen over a MoO3‐SiO2catalyst. The space velocity was varied between 2,500 and 10,000 h−1(at NTP) over a range of temperatures from 848 to 923 K.Selectivities to formaldehyde between 30 and 89% were observed in the 0–5% methane conversion range, the other principal products being CO, CO2, and H2O. Kinetic analysis indicates that methane is directly oxidized to CO2and HCHO, with HCHO being further oxidized to CO. The reactions were all found to be zero order in oxygen concentration, with methane and formaldehyde oxidation following overall first‐order rate laws. Kinetic rate constants have been determined and there is good agreement between model predictions and experime

ISSN:0001-1541    

DOI:10.1002/aic.690331107

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractBoiling heat transfer from a porous layer sintered on a horizontal heater surface and heated from the base was analyzed for laminar to turbulent regions. The effects of the thickness of the porous layer, particle diameter, porosity, pore size distribution, and the properties of fluids on boiling heat transfer were analyzed. Reynolds number, parameter ψ, and a dimensionless heat flux were related to each other. Most experimental data used in this work fall in the region where the vapor Reynolds number is less than 100; very few data exceeded far beyond 1,000.For thick porous beds, the thickness no longer affects the heat transfer. For thin porous beds, heat transfer is affected by the thickness of the porous layer. The prediction equations of various investigators for dryout heat flux were put into dimensionless forms and the differences that exist among the equations are explained

ISSN:0001-1541    

DOI:10.1002/aic.690331108

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractA test has been designed and used to compare flow hydrodynamics in different thermogravimetric analysis (TGA) systems used as pulse microreactors. The test involves passing a pulse of injectant over the sample pan containing an adsorbent. Water and zeolite are used in the present case. The technique is easily performed and is insensitive to variations in temperature. A model is developed by which the fraction of gas pulse bypassing the sample pan within the TGA can be obtained. In gas/solid reactions, either catalytic or noncatalytic, the test should prove useful for comparing TGA extent‐of‐conversion data to similar measurements taken from other reactor configurations, carrier flow rates, and flow geometr

ISSN:0001-1541    

DOI:10.1002/aic.690331109

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractPublished models for gas‐solid reactions have been used with certain modifications to interpret sulfation data for CaO, MgO, and ZnO with SO2and SO3. None of the models evaluated gave an adequate interpretation for high solid conversions, which were found to exceed 90% in some cases. Such high conversions are inconsistent with the current models, and a new mechanism must be postulated to explain the reaction after the solid product theoretically fills the initial pores of the particle. An important factor in successfully interpreting the experimental data is the distributed nature of the pore sizes within the solid particl

ISSN:0001-1541    

DOI:10.1002/aic.690331110

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY

摘要:

AbstractContact nucleation studies were performed with the dextrose‐water system. Under some conditions two crystallographic phases were formed, which were identifiedin situusing a laser Raman microprobe. In addition, the growth of the contact nuclei was monitoredin situusing photomicroscopy. The results are discussed in the context of contact nucleation and growth model

ISSN:0001-1541    

DOI:10.1002/aic.690331111

出版商:American Institute of Chemical Engineers    

年代:1987

数据来源: WILEY