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• Inorganic Chemistry  (752)
• Organic Chemistry  (646)
• Chemical Engineering  (368)
• 1990-1994
• 1970-1974  (1,766)
• 1955-1959
• 1972  (1,766)
Collection
Keywords
Publisher
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• 1990-1994
• 1970-1974  (1,766)
• 1955-1959
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• 1
Electronic Resource
Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 188-193
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A computer program based on the theory of Part I is developed for calculating equilibrium ratios and related thermodynamic properties of mixtures, and a variety of data are used to test the method. For the carbon dioxide-n-butane system both liquid and gaseous compressibility factors are predicted with an average absolute deviation from experimental values of 1.3% for a wide range of conditions. A maximum deviation of 5.4% occurs in the critical region. Derivative properties such as component fugacities and equilibium ratios show somewhat larger deviations as expected. For the same system average deviations are 2.7% for carbon dioxide fugacities, 2.6% for n-butane fugacities, and 3.3% for carbon dioxide and n-butane equilibrium ratios. Average deviation for predicted equilibrium ratios for eight binary systems and 574 data points is 4.6%. Equilibrium ratios for two ternary systems are also predicted accurately. The major advantage of the method, however, is the small or negligible amount of experimental mixture data required. The method has not been tested below a mixture reduced temperature of 0.8, the lower limit of the Pitzer tables. Without density corrections to the scaling parameters best results are obtained if all binary pairs in a mixture fall within range 0.25 〈VCj TCj/VCi TCi 〈 4.0.
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• 2
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 206-212
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Experimental and theoretical transient response data are presented for a tubular reactor with recycle, illustrating the distributed nature of this feedback system. The transient concentration response of an isothermal tubular reactor with recycle was studied experimentally and theoretically for inlet concentration and flow upsets. The reaction studied experimentally was the second order homogeneous liquid phase saponification of methyl acetate with sodium hydroxide.Theoretical models using residence time distribution (RTD) techniques have been developed. The fact that the theoretical model (RTD) predicts the dynamic response data for the recycle reactor with and without reaction in the recycle line for both single flow and concentration upsets verifies that this model is satisfactory for simulation of recycle tubular reactor dynamics.
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• 3
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 221-222
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 4
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 225-227
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 5
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 234-235
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 6
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 240-242
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 7
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 248-249
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 8
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 249-250
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 9
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 43-47
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Theoretical expressions are derived for the fraction of the energy, emitted from a UV lamp, which strikes the reactor wall in systems where a reflecting surface is included. Two geometries used in photoreactors are considered: a cylindrical lamp located at the focus of a superimposed parabolic reflecor. The predicted efficiencies are low, particularly for the elliptical reflector - reactor system, because of the energy that escapes through the ends of the system. Experimentally determined efficiencies for the elliptical type are in reasonable agreement with predicted values, suggesting that the theoretical method may be used for estimating efficiencies for different reactor systems.
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• 10
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 70-77
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The industrial importance of mixtures of closely similar substances is out of proportion to their relatively small numbers due to their frequent occurrence and the difficulty of their separations. A procedure specially designed for the general prediction of their properties, particularly relative volatility, over a wide range of state variables is needed.Such a procedure is developed in this work for convenient application to multicomponent systems with the use of generalized functions. The relative volatility of a nearly ideal system is decomposed into ideal solution factors and nonideality factors. The first order perturbation thory of Longuet-Higgins is adopted for the calculation of the nonideality factor. The validity of the procedure for the quantitative description of real mixtures is demonstrated with the system propane/propylene for which extensive data are available.The required pure fluid properties for the general application of the procedure are reviewed. System parameters are evaluated for 15 binary systems of industrial interest.
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• 11
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 282-286
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Optimal output feedback control low requiring measurment of the output only has been considered for a class of tubular processes. The advantage of this formulation, which requires a single measurement of the output only, over a previous result which requires an infinite number of measurements, has been demonstrated through a heat exchanger example. However, when the terminal time is grater than the residence time of fluid, a time-delay element is needed.
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• 12
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 299-304
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A method is described for solving the problem: given fixed pressure, temperature, the amounts of the chemical elements, and the chemical potentials of possible chemical species at the pressure and temperature specified, determine the equilibrium composition. The method requires a minimum of judgment on the part of the user.A modification of Naphtali's method for direct minimization of Gibbs' function provides an estimate of the composition of sufficient accuracy to insure convergence of solution, by the Newton-Raphson method, of the nonlinear equations describing the equilibrium.Problems in treating multiple phaes of unknown stability and chemical species present in small amouts are handled by ignoring unstable phases and small quantitites in the direct minimization until the amounts of the major consitituents have been at least approximately determined. To accomplish this, species temporarily ignored are assigned a ficitious mol fraction so that their re-entry into the calculation can be established. Truncation errors in the direct minimziation can be tolerated because of the two-step method.Examples of some of the problems solved are given.
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• 13
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 333-337
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Theretical equations for the transport properties of donse gases and liquids require knowledge of the contact pair-correlation function g2 (σ) and the friction coefficient ζ. Usually this latter quantity is made up of a hard-core contribution ζH and a soft-repulsion contribution ζS. Correlations are presented for the reduced friction coefficients ζrH, ζrS, and ζr in terms of reduced density ρ* and reduced temperature T*. These correlations were found to predict the dependence of self-diffusivity of several substances on temeratures and density in the dense gas region.
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• 14
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 326-332
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Exposing one face of a catalyst pellet to a pulse of tracer gas and analyzing the response at the opposite and provides a dynamic method for measuring the effective diffusivity of porous catalysts. The first and second moments of the response peak are shown to be a function of only De and the geometry of the pellet and detector chamber for a nonadsorbing, tracer-carrier system. Data obtained for alumina pellets of different densities ilustrate the method.For an adsorbing tracer, the first moment is a function of both De and the adsorption equilibrium comstant. Measurements for an unconsolidated assembly of nickel/Kieselguhr particles, using the D2-H2 system, show that first-moment data are sufficient to calculate reasonably accurate values of the equilibrium adsorption. However, it appears to be difficult to obtain adsorption rate constants by this method.
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• 15
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 343-346
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A semi-empirical test for the thermodynamic consistency of isobaric liquid-vapor equilibrium data for ethanol-water saturated with a salt is proposed. The test is based upon an adaptation of the Herington method (1) in which the ternary system is treated as a special binary. The test is applied both to full concentration range data and to data which are incomplete at the high alcohol end. For data which are incomplete at the high water end, a less severe test is employed.Literature data for 23 systems composed of ethanol, water, and an inorganic salt at saturation were tested. By the criterion of the proposed test, fourteen were deemed consistent, six were borderline, and three were pronounced inconsistent.
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• 16
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 361-371
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Previously obtained experimental heat transfer data have been collected and are illustrated along with minor variations of the standard correlations. Analysis of data for heat transfer in randomly packed beds and compact (void fraction less than 0.65) staggered tube bundles indicates that the Nusselt number for a wide range of packing materials and tube arrangements is given by \documentclass{article}\pagestyle{empty}\begin{document}$$N_{Nu} = \left({0.5N_{{\mathop{\rm Re}\nolimits} ^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} } + 0.2N_{{\mathop{\rm Re}\nolimits} ^{{2 \mathord{\left/ {\vphantom {2 3}} \right. \kern-\nulldelimiterspace} 3}} } } \right)N_{\Pr ^{{1 \mathord{\left/ {\vphantom {1 3}} \right. \kern-\nulldelimiterspace} 3}} } \left({{{\mu _b } \mathord{\left/ {\vphantom {{\mu _b } {\mu _0 }}} \right. \kern-\nulldelimiterspace} {\mu _0 }}} \right)^{0.14}$$\end{document} provided NRe ≥ 50. The correlations presented in this paper are not necessarily the most accurate available; however, they have wide application, are easy to use, and are quite satisfactory for most design calculations.
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• 17
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 372-380
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The general equations of motion were solved numerically for the laminar isothermal flow of Newtonian fluids from a large tube of circular cross section through an abrupt contraction into a coaxial tube of smaller diameter and through the flow-development region of the smaller tube. The ratio of the diameter of the large tube to that of the smaller tube was varied from one to eight (the latter in one case). Solutions were obtained for the case where the larger tube is real, with no slip at the wall, and for the case where it is a frictionless “stream” tube. The results are presented as charts giving excess pressure losses attributable to contracted and developing flow in terms of equivalent smaller-tube diameters as functions of the tube-contraction ratio and the Reynolds number, which was varied from 0.01 to as high as 500 in one case. Both radial- and axial-velocity profiles are presented. The computed results are shown to be in satisfactory agreement with some experimental data. The results are presented in a manner convenient for use in the design of equipment in which contracted Newtonian flow occurs, such as fiber spinnerettes and heat exchangers, and in the analysis of experimental data for contracted flow.
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• 18
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 416-420
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The effects of axial fluids dispersion on breakthrough curves in packed beds is considered and formulae are derived for ‘F-factors’, which allow heat transfer coefficients obtained by step testing to be corrected for axial fluids dispersion. A comparison of steady state and unsteady correlations for heat transfer in packed beds suggests that axial dispersion effects are incorporated in certain steady state heat transfer correlaions. Further correction would thus lead to errors in breakthrough curve prediction. Experimental data for breakthrough curves in packed beds of highly conductive and poorly conductive spheres is examined and Biot number correction factor 1 + Bi/5 shown to be valid for Biot numbers up to about 4.
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• 19
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 435-437
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 20
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 443-445
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 21
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 446-449
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 22
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 459-461
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 23
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 462-463
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 24
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972)
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 25
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 356-361
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A continuous pump in which the feed and product streams flow steadily both in upflow and downflow is experimentally investigated in the model system toluene-n-heptane on silica gel adsorbent. The experimental data compare reasonably well with analytical results based on an equilibrium theory. The operating conditions necessary to achieve high separation factors are shown to be dependent on the relative magnitudes of penetration distances and the height of the column.
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• 26
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972)
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 27
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 269-276
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A mathematical model of the centrifugal molecular still has been derived based on a fully developed profile, but negligible normal and tangential velocity components. Thermal gradients, film thicknesses, and evaporation rates calculated from this mathematical expression correlate well with reported literative values as well as with the present data.Mean distillation rates were measured for five pure liquids on a centrifugal still with an effective evaporating surface area of 100 sq. cm. These experimentally obtained rates for liquids exhibiting ideal behavior agreed quite well with theoretical values predicted on the basis of simple kinetic theory. In the case of an associated liquid, however, rate measurements were found to be only 53 to 90% of the theoretical value. Although these low values tend to support the concept of an evaporation coefficient as a true molecular property, there wasevidence that surface irregularities could have accounted for all or at least part of the discrepancy noted.
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• 28
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 409-416
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Conditions under which simplified, single parameter models may be used to predict breakthrough curves in linear, packed bed adsorbers and thermal regenerators are examined with reference, in particular, to earlier conditions proposed by Handley and Heggs and by Babcock and co-workers. It is found that for high values of heat capacity ratio the Schumann model provides a satisfactory description of packed bed dynamics where fluids axial dispersion and solids conduction effects are lumped into a single parameter the curve spread parameter σ*. For low values of heat capacity ratio, the equivalent conductivity model of Babcock and co-workers should provide a more accurate description. The value of the Biot number Bi was found to provide the sole criterion for estimating the relative importance of the internal solids conduction. Empirical correlations are presented which allow rapid estimates of breakthrough curves to be made from the curve spread parameter and which facilitate analysis of experimental data from breakthrough curve experiments.
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• 29
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 432-434
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 30
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 439-442
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 31
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 451-451
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 32
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 454-456
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 33
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 462-462
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 34
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 464-464
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 35
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. i
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 36
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 491-497
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A fiber optic technique for obtaining multiple, simultaneous, point residence time distributions on operating, commercial scale distillation trays is described. The method has sufficient resolution to yield residence time profiles on the tray and to separate tray and downcomer effects. The results indicate severe flow nonuniformities on the tray, which are not accounted for in present models of distillation.
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• 37
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 647-649
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
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• 38
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 654-656
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
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• 39
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 527-533
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The problem of developed turbulent heat or mass transfer in a duct is considered for the limit of large σ (Prandtl or Schmidt number). The limiting results depend on the behavior of the eddy diffusivity near the solid surface. Since there is a question about whether this variation begins with ∊ ∝ y+3 + … or ∊ ∝ y+4 + … for y+ near zero, both possibilities are considered. In each case the first three terms of the asymptotic expansion for σ → ∞ are obtained. The first term of the asymptotic expansion agrees with limiting results derived earlier, while the correction terms indicate the errors associated with earlier simplifying assumptions.By proper scalling, it is demonstrated that in the limit of σ → ∞ the results are independent of geometry and boundary conditions for situations involving parallel plates, circular tubes and concentric annuli with either constant surface heat flux or temperature. The correction terms to the σ → ∞ asymptote can be significant, although the effect of Reynolds number on the correction terms is very small.A comparison between a typical numerical integration and the asymptotic formula shows excellent agreement. The asymptotic formulae are used to correlate large Schmidt number mass transfer data.
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• 40
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 671-671
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
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• 41
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 452-454
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 42
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 457-458
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
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• 43
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 463-463
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 44
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 465-478
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 45
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 486-490
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The rate at which water is extracted from thoria sols was investigated by fluidizing single thoria sol droplets in 2-ethyl-1-hexanol (2EH) and measuring the diameter of a droplet over a period of time until shrinkage no longer occurred. Diameter data from both water and sol drops were obtained at 25°C. The experimental variables were initial drop diameter (0.1 to 0.2 cm), sol molarity \documentclass{article}\pagestyle{empty}\begin{document}${\rm (0 to 2}{\rm .5 }\underline M {\rm ThO}_{\rm 2})$\end{document}, and water concentration in the 2EH (2-12 mg./cc.). The water and sol droplet data were correlated by Equation (5). The single relationship for the fluidized water and sol drops verified that an organic-phase film surrounding the drop is the rate-controlling resistance. The sphere Reynolds number was based on the approach velocity and varied from 0.4 to 14. The Schmidt number for the system was fixed at 35,700. During the extraction of water, the mass transfer coefficients for fluidized sol drops were found to depend only on the molarity of the sol. By expressing the mass transfer coefficients as a function of the density difference between the aqueous sol and the organic phase, an equation was derived to predict the gelation time required for any initial sol molarity and drop diameter fluidized in 2 EH at 25°C.
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• 46
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 520-526
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The retention of trace volatile components in food liquids during low temperature drying processes is analyzed through a ternary diffusion model. Flux equations for both water and trace organic components are solved numerically for typical drying situations. Several effects are found with the ternary analysis which are not evident from a simpler binary model. The sugar-water composition gradient which develops during drying causes an appreciable transport of the trace volatile species. This transport can occur in the same direction as the transport resulting from the concentration gradient of the volatile species, or in the opposite direction, and can result in a local accumulation of the volatile species. Concentration profiles for both water and dilute volatile components were experimentally measured during nearly isothermal drying of gelled slabs of synthetic sugar solutions and natural fruit juice concentrates. The predicted internal maximum in volatiles concentration is borne out by the experiment, and a satisfactory agreement of observed with predicted volatiles retention is found, within the limits of the experiment.
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• 47
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 540-547
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Elongational flow experiments with viscous polymeric material were conducted at a constant elongation rate on a modified tensile testing machine. Steady elongational and shear viscosity data and elongational stress growth data are presented for an isobutylene-isoprene copolymer at 100°C. S-shaped elongational stress growth curves are reported for cis-1,4-polyisoprene at 80°C.The stresses necessary to maintain a cylindrical specimen in steady elongational flow are indicated by a calculation which includes the effects of inertia, gravity, and interfacial tension.Interrelations among several elongational flow material functions are given for a constitutive equation based on the theory of linear viscoelasticity.
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• 48
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 561-568
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Unpredictable variations in the values of plant parameters around their nominal values are often encountered in actual operation of process plants. In order to assure that process performance meets specifications, it is preferable to design and control the process, taking into account the uncertainty in the values of the plant parameters. In this paper, a method to minimize the maximum decrease in the process performance caused by the hypothetical worst parameter variations is proposed. Necessary condition for the worst parameter variations is derived for a class of distributed parameter systems by means of the maximum principle, and then the method for obtaining the optimal design and control subject to the worst parameter variations are discussed. The method is applied to the design of a tubular reactor associated with catalyst activity decay. The reactor obtained is fairly insensitive to the variations in the process parameters while maintaining fairly good performance even at the nominal values of parameters.
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• 49
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 572-581
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The dynamic response of a packed gas absorber to inlet gas composition changes was investigated by the pulse response technique for the case where absorption was accompanied by pseudo first-order irreversible chemical raction.The solute-carrier-solvent system was carbon dioxide-air-0.07 normal aqueous sodium hydroxide solution. The column used was 6.5 in. I.D. Plexiglass packed to a height of 6.15 ft. with either ¼-in. Raschig rings or ¾-in. Berl Saddles. Gas flow rates ranged from 1.5 to 10 lb.-moles/hr./sq.ft. and liquid flow rates ranged from 0 to 200 lb.-moles/hr./sq.ft. A pulse of carbon dioxide was injected into the inlet air stream and monitored as it entered the packed section. The outlet gas and liquid phase concentrations were continuously monitored as the resulting pulses left the packed section. The pulse response data were reduced to frequency response by digital computer calculations. Reliable data could be obtained over the frequncy range 0 to 5 radians/second.The experimental results were compared with theoretical predictions from the slug flow, axial diffusion, and mixing cell models. Both the mixing cell model and the axial diffusion model satisfactorily predicted the experimental frequency responses over the entire frequency range covered. The slug flow model was found unsatisfactory for predicting gas-phase amplitude ratios at high frequencies, where axial mixing affected the amplitude ratios. Gas-phase particle Peclet numbers and overall mass transfer coefficients based on the gas-phase driving force determined in the present absorption system were in reasonable agreement with the values reported in the literature.
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• 50
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 608-613
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The kinetics of binary anion exchange accompained by a fast irreversible reaction at the exchanger surface was studied. Dowex 1, X-8, in the hydroxyl form was contacted with a strong acid in a well-stirred batch reactor and concentration-time data were obtained by electrical conductivity measurements. The process was analyzed assuming rate control by film diffusion, intraparticle diffusion, and a combination of both mechanisms. The results indicated that models based on the individual mechanisms gave quite satisfactory representations of the data under appropriate conditions, but the combined model appears superior in the nominally intraparticle diffusion controlled range. It was also found that severe particle cracking occurs, particularly with larger resin particles, at high solution concentrations. This results in degradation of the particles as well as apparent intraparticle diffusion coefficients that vary during the exchange process. Care must be taken to avoid or to account for this phenomenon.
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• 51
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 623-627
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Heat transfer in packed beds can be mathematically modeled to account for the heat transfer between the particles and the gas phase, the conduction through the solid phase of particles, and the mixing or dispersion within the gas phase in the void structure of the porous media. To solve the resulting differential equations numerically is not easy. The solution for sinusoidal gas temperature input assumes linearity of the logarithm of the temperature with time. If, in addition, linearity with distance can be assumed, then the solution can be vastly simplified to finding the real root of a fourth-order algebraic equation.
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• 52
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 644-647
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 53
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 639-642
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The sorption isotherms for moist air and Florite were determined at a total pressure of one atmosphere and 75°, 100°, 125°, 150°, 175°, and 200°F. No hysteresis was evident.An investigation of the sorption isotherms showed that a concentration-temperature coordinate could be identified, which when plotted against amount sorbed, causes all sorption isotherms to collapse into a single sorption therm.For purposes of sorption curve fitting the concentration-temperature coordinate was incorporated into a version of BET theory. This relation produced an excellent fit of data without resorting to more complicated versions of BET theory.The concentration-temperature coordinate was also incorporated into a modified version of Langmuir-Hey theory to show that this interpretation also leads to a very satisfactory fit of sorption data.Some additional observations are made concerning the computerized curve fitting technique as applied to silica gel, the data for which were reported in an earlier publication.
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• 54
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 653-654
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 55
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 879-879
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 56
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 880-880
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 57
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972)
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 58
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 892-903
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The problem of mercury losses from chlorine plants is reviewed. The mercury material balance is difficult to establish because mercury escapes from the process by a number of routes. Some of the reasons for the mercury emissions are explored, and some problems involved in the measurement of mercury in various effluents are discussed.A number of mercury containment processes for specific streams have already been proposed, but the need for an integrated mercury recycle policy still exists.
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• 59
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 923-928
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Based on a Lagrangian interpolation, a heuristic scheme is developed for the inversion of certain types of Laplace transforms and is applied to the solution of problems of interest to chemical engineers for which the exact solution is either very difficult or impossible to obtain. The solutions thus obtained are in good agreement with exact values, when available, for initial values of the transformed independent variable and may therefore be used as approximations. Three illustrative examples are presented.
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• 60
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 928-934
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Mass transfer into dilute polymeric solutions was studied by using a short wetted-wall column. Oxygen was absorbed into thin films of water and aqueous polymeric solutions. The polymer systems studied included dilute solutions of carboxymethylcellulose, polyethylene oxide, Carbopol, and Cyanamer. All of the above systems were moderately non-Newtonian with power law indexes less than unity. Methocel (a Newtonian fluid with a power law index of one) was also studied. The flow of liquid films was well within the laminar flow regime.The rheological properties of these solutions as well as equilibrium solubility of oxygen in these solutions were determined. In all of the polymer systems studied except Polyox the equilibrium so ubility of oxygen decreased with an increase in polymer concentration. In Polyox solutions, however, the equilibrium solubility of oxygen increased with an increase in polymer concentration.For all of the systems investigated (including Polyox) the mass transfer coefficient for absorption of oxygen at a given flow rate decreased with an increase in polymer concentration. The mass transfer coefficient was highest for water at all flow rates.The diffusivity of oxygen in all of the systems considered except Polyox was lower than that in water. This was attributed to the increased viscosity of the polymeric solutions. The diffusivity of oxygen in Polyox solutions was higher than it was in water. This was found to be due to the complex chemical reactions which occur in this system. In all of the pseudoplastic systems studied the diffusivity of oxygen increased with increasing wall shear rate (decreasing viscosity).
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• 61
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 967-975
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: When the dusty gas diffusion equation is applied to materials containing pores with radii below 50 Å, the observed diffusion behavior in these smaller pore systems can be quite different from that predicted by the equation. Higher temperatures and in some cases higher pressures tend to lessen the deviations between prediction and experiment. The observed deviations are probably caused by surface transport and by momentum transfer between gas molecules and pore walls during molecular flight. For bimodal materials, an additional factor can be the inapplicability of the equation to systems of parallel micro- and macropores. Excellent agreement between theory and experiment occurs for large-pore unimodal systems.
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• 62
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 990-998
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: An experimental investigation was made of oxygen dissociation in a radiofrequency discharge. The conversion and yield were examined as a function of power, pressure, and gas flow rate. These measurements were supplemented by measurements taken with catalytic and noncatalytic thermocouple probes in order to determine the local gas temperature and atomic oxygen concentration. An interpretation of the results is given in terms ofa theoretical model of the reactor.
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• 63
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 1010-1015
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The onset of secondary flow between rotating cylinders (Taylor vortices) was observed for a dilute polymer solution whose viscometric flow properties were characterized rheogoniometrically. The critical Taylor number (flow onset) was predicted accurately by linear stability theory with a stress constitutive equation describing viscometric behavior. The cell spacing differed significantly from that predicted by linear theory. A nonlinear analysis shows that Linear theory will predict the ultimate cell size only for an inelastic liquid. For an elastic liquid a larger wave number (closer spacing) is a lower energy configuration than the linear theory spacing. This is consistent with experiment.
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• 64
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 1024-1029
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Orthophosphate and fluoride are simultaneously precipitated from aqueous solution, 5.26 × 10-3 M. in each, by La (III). The precipitates are cofloated by the anionic surfactant sodium laurylsulfate, with optimum flotation at pH 4.0 and a stoichiometric lanthanum concentration based on LaPO4 and LaF3. Over pH 3.5 to 6.0, better than 95% flotation of the total orthophosphate and precipitated fluoride that-are present can be floated at a molar sodium laurylsulfate to orthophosphate plus fluoride ratio of 0.023. At lower sodium laurylsulfate concentrations, the flotation decreases at pH 3.5 and 6.0 compared to pH 4.0-5.0; at pH 4.0, an increase in the La(III) concentration decreases the flotation.
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• 65
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 1048-1052
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Design charts that give the value of the gain of a proportional sampleddata controller for various closed loop damping coefficient specifications are presented. Charts for first- and second-order processes with various deadtimes are given over a range of sampling rates.Typical root locus plots in the z plane are also presented to illustrate how increasing deadtime (as an integer multiple of the sampling period) increases the order of the system in the z domain.
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• 66
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 1062-1063
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 67
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 976-984
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: This paper presents three methods of designing feedforward compensators which can be combined with multivariable feedback controllers in order to minimize or eliminate errors caused by sustained measurable disturbances. The designs are based on a linear, time-invariant state-space model of the process and minimize a quadratic function of the errors and/or constrain selected steady state offsets to zero. Simulated and experimental data from a computer controlled pilot-plant evaporator show that multivariable feedback-plus-feedforward control is relatively simple to implement, is practical, and gives excellent control.
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• 68
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 18 (1972), S. 999-1004
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A new method of incorporating binary interaction data into the BWR equation is proposed. It is developed to predict phase equilibria and enthalpies for multicomponent mixtures using interaction data for 18 binaries.A calorimeter is described, together with experiments made upon it, for a 6-component simulated North Sea Gas mixture at three pressure levels from 18 to 36 bar, and over a temperature range from 373 to 188K. The experimental enthalpy results are claimed to have an accuracy of ± 0.9%. These results are compared with the predictions of the modified BWR equation. The average deviation is 1.1%, the values being negative at about 18 bar and generally positive for the higher pressures tested.