摘要:

AbstractThis review covers the field of liquid diffusion form the time of the publication of the review article by Johnson and Babb in 1957. In Part I a concise introduction is given to the phenomenological description of the diffusion process, followed by a review of the various theories of and model approaches to diffusion in binary mixtures. These are treated in the following categories: hydrodynamic theories, Eyring's theory and the friction coefficient theories. The predictions are compared with the experimental results throughout the review. Part I will be followed by Part II in November reviewing self‐diffusion, empirical predictive equations, and experimental techniques. A supplement of critical tabulations of all experimental diffusion data since 1956 has been prepare

ISSN:0001-1541    

DOI:10.1002/aic.690190502

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractThe effectiveness of the stationary form of the discrete Kalman filter for state estimation in noisy process systems was demonstrated by simulated and experimental tests on a pilot plant evaporator. The filter was incorporated into a multivariable, computer control system and resulted in good control despite process and/or measurement noise levels of 10%. The results were significantly better than those obtained when the Kalman filter was omitted or replaced by conventional exponential filters. In this application the standard Kalman filter was reasonably insensitive to incorrect estimates of initial conditions or noise statistics and to errors in model parameters. The filter estimates were sensitive to unmeasured process disturbances. However this sensitivity could be reduced by treating the noise covariance matrices R and Q as design parameters rather than noise statistics and selecting values which result in increased weighting of the process measurements relative to the calculated model states.

ISSN:0001-1541    

DOI:10.1002/aic.690190503

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractStability of interfaces moving as a result of phase transformation or mass transfer is considered. Effects of transport and of the density difference between phases known to significantly influence stability during solidification and combustion respectively are here studied theoretically in fluid systems. The analysis indicates that instability is possible during vaporization of liquids under vacuum and perhaps during growth of cavitation bubbles. But except when interfacial tension is very low, instability is unlikely during mass transfer in liquid‐liquid systems because the density difference between phases is small. A density difference can also produce cellular convection at an unstable interface during solidificatio

ISSN:0001-1541    

DOI:10.1002/aic.690190504

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractMeasurements were made of mass transfer coefficients with gas and liquid phase controlling resistance using a concurrent flow packed column with a wide range of operating conditions and four types of packing.Mass transfer coefficients were much larger than those obtainable in countercurrent towers.The results were correlated with dissipated energy values. The correlations obtained can be used to determine absorption efficiency. Experimental results show that the use of a high velocity concurrent flow column is particularly suitable when mass transfer is controlled by the liquid phase resistance with chemical reaction in the liquid.

ISSN:0001-1541    

DOI:10.1002/aic.690190505

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractTemperature control of subcooled reflux in a distillation column was studied experimentally using coolant flow rate as the manipulative variable. Methanol vapor was condensed and subcooled at one atmosphere in a vertical heat exchanger with 210 copper tubes (0.77 cm I.D., 91.5 cm long). Cooling water flowed countercurrently through the shell side (20.6 cm I.D.).A proportional‐integral feedback controller provided good temperature control at normal design throughputs. But dynamic control performance deteriorated at low throughputs (or large areas). Thus the normal conservative design practice of providing excess area in this type of condenser leads to poorer temperature contro

ISSN:0001-1541    

DOI:10.1002/aic.690190506

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractThe Lighthill transformation is used to determine the rate of mass transfer at high Schmidt numbers to a disk imbedded in a stationary plane below a rotating disk. This diffusion‐layer solution breaks down near the center and leading edge of the mass‐transfer disk. Solutions in these regions are reported, and a uniformly valid composite solution for the local Nusselt number is determined along with an expression for the average mass‐transfer rate to the

ISSN:0001-1541    

DOI:10.1002/aic.690190507

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractAn algorithm that combines structural equation analysis with algebraic rearrangement and substitution has been developed to precedence‐order algebraic chemical process equations. The SWS (Structural Analysis with Substitutions) algorithm selects an output variable for each equation, rearranges the equation to solve for that variable, and reduces the number of equations by substitution. The algorithm has been used for computer generation of Fortran programs to perform meterial and energy balances in the design of chemical processe

ISSN:0001-1541    

DOI:10.1002/aic.690190508

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractThe free‐volume theory of polymer solutions initiated by Prigogine and developed by Flory and Patterson is reduced to practice. This theory, which represents a substantial improvement over the older theory of Flory and Huggins, facilitates calculation of solvent activities in polymer solutions from a minimum of experimental binary data. However, it is necessary to characterize each pure component with three molecular parameters which can be obtained from PVT data; such data, unfortunately, are often unavailable. Nevertheless, using reasonable approximations based on Bondi's correlations as needed, molecular parameters are given for 22 solvents and for 16 polymers. Binary parameters are given for 20 systems. Illustrative examples are presente

ISSN:0001-1541    

DOI:10.1002/aic.690190509

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractThe System of isothermal, isobaric, perfect gas reactions with stoichiometric kineticstaking place in a tubular reactor is considered whereA3is desired andA5undesired. A class of optimum selectivity problems is formulated, and distributed bypass ofA1is investigated. It is shown that there are cases where the performance of the best plug flow reactor can be improved substantially (sometimes by more than 100%) by the bypass ofA1, but there are also cases where bypass is fruitless.

ISSN:0001-1541    

DOI:10.1002/aic.690190510

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY

摘要:

AbstractThe secondary nucleation of magnesium sulfate due to the action of fluid forces on a seed crystal was studied by introducing the hypothesized nuclei so generated into a region of high supersaturation. The number of nuclei observed is strongly dependent on the supersaturation at the seed and the severity of shear forces. Classical nucleation theory is used to interpret the results. These results are consistent with other experimental observations described in the recent literature on contact nucleation. The growth and nucleation process inferred is similar to that illustrated by Clontz and McCabe (1972) and suggested by Knight (1971).

ISSN:0001-1541    

DOI:10.1002/aic.690190511

出版商:American Institute of Chemical Engineers    

年代:1973

数据来源: WILEY