摘要:

AbstractThis paper investigates the application of spatially adaptive numerical methods in the solution of one‐dimensional premixed combustion problems. The selection of grid points by equidistribution of positive weight functions across consecutive mesh intervals is considered. The method is applied in the solution of a steady premixed laminar flame problem and a time‐dependent freely propagating flame problem. The adaptive numerical results are compared with corresponding equispaced calculati

ISSN:0001-1541    

DOI:10.1002/aic.690320802

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractMultiresponse kinetic models are established for the low‐temperature oxidation (LTO) reactions of Athabasca oil sands bitumen. The models provide adequate description of the overall rate of oxygen consumption and of the reactions of the liquid phase bitumen components. The LTO models are suitable for use in thein situcombustion numerical simulators of the oil sand

ISSN:0001-1541    

DOI:10.1002/aic.690320803

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA universally valid formal expression for the composition dependence of solute and solvent fugacity coefficients in any dilute binary system far from criticality is derived in this paper. In the present context, dilution denotes they1→ O limit, regardless of the mixture's molar density. The results are independent of the system under study and of the choice of equation of state. The solute fugacity coefficient is simply the product of a composition‐independent term (the infinite dilution fugacity coefficient) and an exponential decay composition correction. These two parameters have important thermodynamic implications: their temperature and pressure derivatives are related to the solute's partial molar enthalpy and volume, respectively. When applied to activity coefficients, the same theoretical analysis yields universal relationships for the composition dependence of activity coefficients which can be used as consistency checks for empirical correlations. The relationship between infinite dilution activity and fugacity coefficients can be used to estimate relative solubilities of a given solute in different solvents. Excellent agreement is found when the theoretical expressions are tested with three different binary systems involving a nonvolatile solid solute and a supercritical fl

ISSN:0001-1541    

DOI:10.1002/aic.690320804

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractExperimental gas‐solid adsorption measurements were made on the binary and ternary mixtures of H2S, CO2, and C3H8on H‐mordenite molecular sieve zeolite at 30°C. The C3H8containing binaries and the ternary mixture exhibited nonideal behavior, as evidenced by the azeotropelike crossovers in the composition domains and by the peaks in the total amount adsorbed surface. The ternary data were successfully predicted with the activity coefficients calculated by the spreading‐pressure‐dependent equation. Models that neglect the spreading‐pressure dependence can only qualitatively predict the non

ISSN:0001-1541    

DOI:10.1002/aic.690320805

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractBased on the concept of reactions in a continuum, a mathematical model has been developed to simulate coal liquefaction kinetics. In an excess hydrogen donor environment, the rate‐limiting reactions are considered to be irreversible cracking reactions involving cleavage of carbon and oxygen linkages. Concurrent evolution of a wide spectrum of products, with an initial rapid formation of species of high carbon and oxygen contents, followed by progressively slower reactions leading to lower carbon and oxygen content species is predicted. Simple lumping functions are employed to obtain conventional lumped pseudocomponents (preasphaltenes, asphaltenes, and oils). Parameter analysis has been carried ou

ISSN:0001-1541    

DOI:10.1002/aic.690320806

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractExperimental kinetic data for three Australian coals are compared with predictions from the mathematical model developed in Part I. For these coals, as well as data reported for North American coals, the model is found to show good agreement, using the characteristic molecular weight as the only parameter. The effects of reaction time and temperature are coupled via a severity index that arises in the model as a dimensionless reaction time. The model is also shown to be applicable when catalysts are present. The product distribution for a particular coal seems to be a function only of the conversion even in the presence of catalysts, as long as the chemical reaction controls the rate of liquefaction.

ISSN:0001-1541    

DOI:10.1002/aic.690320807

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA mathematical model is developed to simulate the drying of hygroscopic porous media and, in particular, of wood. Drying rate experiments were performed using wood specimens and a nonhygroscopic porous ceramic solid and were simulated using the appropriate version of the drying model. Calculated model predictions are in very satisfactory agreement with experimental results. An examination of the relative impacts on drying of the transport mechanisms that comprise the model leads to meaningful interpretations of observed drying behavior. Controlling rate factors can be identified and different types of drying behavior specific to a given material or drying condition can be explained and understood through model simulation studies. Such capability can provide important guidance for drying process design and control.

ISSN:0001-1541    

DOI:10.1002/aic.690320808

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThe yield of a nonpremixed series‐parallel reaction at complete conversion was measured in a turbulent, tubular‐flow reactor with single and multijet feeds. The yield of the intermediate decreased as mixing was slowed relative to the chemical kinetics, either by decreasing the Reynolds number, or by using a less efficient mixing device, or by increasing the feed concentration.Four models, a modified slab model, a modified stretch model, the Harada mass transfer model, and a new closure model, adequately predict the yield when chemical and mixing kinetics are known from independent measurements of the conversion of acid‐base reactions. Without modification, the original slab and stretch models are unable to account for the earlier observed invariance of conversion to Schmidt number of very rapid, single‐step reactions or to satisfactorily predict the yield of the series‐parallel

ISSN:0001-1541    

DOI:10.1002/aic.690320809

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA molecular‐thermodynamic correlation has been developed for calculating the inhibition effect of methanol on the formation of hydrates in moist gas mixtures. Six phases are potentially present in these mixtures: gas, aqueous liquid, hydrocarbon liquid, ice, and hydrate structures I and II. For a given temperature and system composition, the molecular‐thermodynamic method described here allows computation of the hydrate‐point pressure as well as relative amounts and compositions of all coexisting phases. Good agreement is obtained when calculated results are compared with diverse experimental data reported in the literature. The correlation given here may be useful for computeraided design for gas processing and transport

ISSN:0001-1541    

DOI:10.1002/aic.690320810

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA receding interface model of the drying of single drops of slurries of sodium sulfate decahydrate has been developed to describe the drying characteristics of this material and to estimate the drying rates of particulate slurries. The simultaneous heat and mass transfer rate equations have been solved numerically, and the results obtained have been compared with those obtained experimentally by drying single drops suspended on the tip of a glass filament.Single drops of slurries, 1.0 to 1.5 × 10−3m dia., were suspended on the tip of a flexible glass cantilever inserted in a vertical wind tunnel. A 50μm dia. nickel wire passed through the center of the glass beam and the outer surface was coated with a thin film of copper, thereby forming a thermocouple that measured the temperature of the core of the drop; the deflection of the beam gave the loss in weight during drying. In this way the instantaneous drying rate and drop temperature were determined and compared with those predicted by the receding interface model. In all cases the agreement between the predictions of the model and experimental results was g

ISSN:0001-1541    

DOI:10.1002/aic.690320811

出版商:American Institute of Chemical Engineers    

年代:1986

数据来源: WILEY