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Articles 1351 - 1380 of 1405

Full-Text Articles in Chemical Engineering

The Effects Of Interstage Backmixing On The Design Of A Multicomponent Distillation Column, Gary D. Loud, Raymond C. Waggoner Jan 1978

The Effects Of Interstage Backmixing On The Design Of A Multicomponent Distillation Column, Gary D. Loud, Raymond C. Waggoner

Chemical and Biochemical Engineering Faculty Research & Creative Works

Interstage back mixing is encountered as entrainment in many distillation columns. Bidirectional back mixing is common in liquid-liquid extraction. These effects, which reduce the effectiveness of a separation process, may interfere with its operation even to the extent of shutdown. The design engineer and process operator need to recognize the effects of back mixing and must quantify them to take effective countermeasures. A procedure is developed which describes the effects of interstage bidirectional back mixing in multistage separations. It is implemented on an existing simulation for multicomponent distillation and is used to show the effect of back mixing on product …

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Laser Doppler Velocimetry Studies Of Early Turbulence, J. L. Zakin, C. C. Ni, R. J. Hansen, M. M. Reischman Jan 1977

Laser Doppler Velocimetry Studies Of Early Turbulence, J. L. Zakin, C. C. Ni, R. J. Hansen, M. M. Reischman

Chemical and Biochemical Engineering Faculty Research & Creative Works

Laser Doppler anemometry is employed to measure the mean velocity and turbulence intensity in the early turbulence regime of the flow of a dilute polymer solution through a small-diameter tube. (This regime is initiated at an onset Reynolds number in the subcritical range, above which the polymer additive increases drag, and continues through the transitional Reynolds number range, where a continuous transition to turbulent flow with reduced drag is observed.) When the onset flow rate for early turbulence is exceeded, the mean velocity profile becomes progressively flatter with increasing flow rate. That is, a gradual transition from a laminar profile …

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Direct Solution Of The Isothermal Gibbs‐Duhem Equation By An Iterative Method For Binary Systems, J. A. Martinez‐Ortiz, David B. Manley Jan 1977

Direct Solution Of The Isothermal Gibbs‐Duhem Equation By An Iterative Method For Binary Systems, J. A. Martinez‐Ortiz, David B. Manley

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Turbulence Structure In Drag Reducing Polymer Solutions, Gary Kent Patterson, Jack Chosnek, J. L. Zakin Jan 1977

Turbulence Structure In Drag Reducing Polymer Solutions, Gary Kent Patterson, Jack Chosnek, J. L. Zakin

Chemical and Biochemical Engineering Faculty Research & Creative Works

Longitudinal turbulence intensifies measured by split-film anemometry in degraded polymer solutions in pipe flow peaked much farther from the wall than longitudinal turbulence intensities in a Newtonian oil at the same Reynolds numbers. The peak values were at about the same level for the degraded solutions as for the oil but were higher and nearer the wall for fresh polymer solutions. Radial turbulence intensities were lower for the polymer solutions at all locations under all conditions. Drag reduction for the polymer solutions ranged from 1 to 21% based on Newtonian fluid of equal viscosity. For the fresh solutions the Reynolds …

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Synthesis Of Heat Exchange Networks By Mixed Integer Optimization, R. C. Kelahan, J. L. Gaddy Jan 1977

Synthesis Of Heat Exchange Networks By Mixed Integer Optimization, R. C. Kelahan, J. L. Gaddy

Chemical and Biochemical Engineering Faculty Research & Creative Works

Process synthesis involves manipulation of the process arrangement, while studying the variables of each arrangement, to arrive at the optimal process. If each process arrangement is treated as a discrete variable, process synthesis becomes a mixed integer optimization problem. This paper examines the synthesis of heat exchanger networks using the adaptive random search procedure, which can be used to search continuous and discrete independent variables simultaneously. The means of handling the heat exchanger arrangement as a discrete variable is discussed, and the incorporation of various synthesis heuristics is presented. The results of synthesis of 2 x 2, 2 x 3, …

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Optimization Of Methanol Process By Flowsheet Simulation, S. H. Ballman, J. L. Gaddy Jan 1977

Optimization Of Methanol Process By Flowsheet Simulation, S. H. Ballman, J. L. Gaddy

Chemical and Biochemical Engineering Faculty Research & Creative Works

Optimization of large complex chemical processes is a necessary step in economic design of these systems. Flowsheet simulation models afford an ideal mechanism for detailed optimization of these processes. The methanol process offers several interesting optimization variables (reformer temperature, pressure, and steam and carbon dioxide to hydrocarbon ratios; synthesis loop pressure, temperature, purge rate, and conversion) which require detailed models of the reaction kinetics. This paper presents the results of optimization of the intermediate pressure process using the PROPS model and the adaptive random search routine. The costs associated with performing such a detailed process optimization study are easily justified …

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An Examination Of The Adaptive Random Search Technique, M. W. Heuckroth, J. L. Gaddy, L. D. Gaines Jan 1976

An Examination Of The Adaptive Random Search Technique, M. W. Heuckroth, J. L. Gaddy, L. D. Gaines

Chemical and Biochemical Engineering Faculty Research & Creative Works

Random search procedures have recently been successfully applied to the optimization of a variety of chemical engineering problems, including optimization of chemical processes by flow sheet simulation. These procedures represent the independent variables as random variables described by probability distributions. The adaptive random search procedure centers the distribution for each variable about the best search point found and examines this region for a better point. Thus, this technique has the ability of continuously moving the search region toward the optimum, which is particularly advantageous in following constraints. This study examines the efficiency of the adaptive random search technique as applied …

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Mass Transfer To Drops Moving Through Power Law Fluids In The Intermediate Reynolds Number Region, Robert M. Wellek, Türker Gürkan Jan 1976

Mass Transfer To Drops Moving Through Power Law Fluids In The Intermediate Reynolds Number Region, Robert M. Wellek, Türker Gürkan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The mass transfer rate to fluid spheres is calculated for power law and Newtonian fluids by using the intermediate Reynolds number stream functions of Nakano and Tien (1970) and Yamaguchi et al. (1974), respectively. The Sh increases with increases in Re and Pe and decreases in n. Better results are obtained with Nakano and Tien's functions when Re > 10 and with Yamaguchi's functions when Re < 10. Copyright © 1976 American Institute of Chemical Engineers

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Mass Transfer In Dispersed And Continous Phases For Creeping Flow Of Fluid Spheres Through Power Law Fluids, Türker Gürkan, Robert M. Wellek Jan 1976

Mass Transfer In Dispersed And Continous Phases For Creeping Flow Of Fluid Spheres Through Power Law Fluids, Türker Gürkan, Robert M. Wellek

Chemical and Biochemical Engineering Faculty Research & Creative Works

The diffusion equation was numerically solved by an implicit finite-difference method for the purpose of calculating the continuous phase Sherwood number, Sh, for mass transfer from an internally circulating Newtonian droplet traveling through a non-Newtonian power-law-type continuous phase in the creeping flow regime. The Mohan stream functions were used in the calculations in order to approximate the velocity profile inside and outside the droplet. The calculated Sh is presented as a function of the Peclet number, Pe, power-law index, n, and a viscosity ratio parameter, X. Sh increases as n decreases in the pseudoplastic region. The dependence of Sh on …

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Generalized Correlations For Molecular Weight And Concentration Dependence Of Zero-Shear Viscosity Of High Polymer Solutions., J. L. Zakin, R. Wu, H. Luh, Kenneth G. Mayhan Jan 1976

Generalized Correlations For Molecular Weight And Concentration Dependence Of Zero-Shear Viscosity Of High Polymer Solutions., J. L. Zakin, R. Wu, H. Luh, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Results of a study are presented which show that two correlations of viscosity-concentration data are useful representations for data over wide ranges of mol. wt and up to at least moderately high concentrations for both good and fair solvents. Low mol. wt polymer solutions (below the critical entanglement mol. wt M//c) generally have higher viscosities than predicted by the correlations. One correlation is eta //s//p/c left bracket eta right bracket versus k prime left bracket eta right bracket c, where eta //s//p is specific viscosity, c is polymer concentration, left bracket eta right bracket is intrinsic viscosity, and k prime …

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Process Optimization By Flow Sheet Simulation, L. D. Gaines, J. L. Gaddy Jan 1976

Process Optimization By Flow Sheet Simulation, L. D. Gaines, J. L. Gaddy

Chemical and Biochemical Engineering Faculty Research & Creative Works

Optimization of large or complex chemical processes often requires simplifying the system to reduce the mathematics to a form manageable by available algorithms or to reduce the time required to perform the computations. In many cases, such simplification alters the solution of the problem. Flow sheet simulation programs are ideally suited to the study of chemical processes, although the computational time is generally considered excessive for detailed optimization of complex systems by the usual procedures. This paper discusses the modifications needed to apply flow sheet simulation programs to the optimization of chemical processes. The advantages and disadvantages of the use …

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Transition Boiling Of Normal Pentane From A Horizontal Flat Gold Surface At One Atmosphere Pressure, R. M. Canon, Efton Park Jan 1976

Transition Boiling Of Normal Pentane From A Horizontal Flat Gold Surface At One Atmosphere Pressure, R. M. Canon, Efton Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Use Of Sodium Chloride Windows In The Infrared Spectral Analyses Of Irradiated Thin Insoluble Polymer Films, W. F. Oberbeck, Kenneth G. Mayhan Jun 1975

Use Of Sodium Chloride Windows In The Infrared Spectral Analyses Of Irradiated Thin Insoluble Polymer Films, W. F. Oberbeck, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Mechanical Degradation Of Dilute Solutions Of High Polymers In Capillary Tube Flow, John D. Culter, Jacques L. Zakin, Gary Kent Patterson Jan 1975

Mechanical Degradation Of Dilute Solutions Of High Polymers In Capillary Tube Flow, John D. Culter, Jacques L. Zakin, Gary Kent Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

Experimental results on mechanical degradation in capillary tubes of polyisobutylene polymers in dilute solution are described. In laminar flow, degradation is independent of tube length, indicating that entrance effects are dominant. This shows that capillary experiments do not yield explicit information on the effect of shear stress on mechanical degradation. In turbulent flow, large entrance effects are also observed, but some degradation does take place in the fully developed flow region. Copyright © 1975 John Wiley & Sons, Inc.

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Quantitative Overdesign Of Chemical Processes, R. A. Freeman, J. L. Gaddy Jan 1975

Quantitative Overdesign Of Chemical Processes, R. A. Freeman, J. L. Gaddy

Chemical and Biochemical Engineering Faculty Research & Creative Works

Overdesign is applied to chemical processes to account for expected variations in the design data or design conditions. These variables must be treated quantitatively in order to design a process that is certain to perform adequately. Process dependability is introduced as a means of quantifying variable process behavior. Overdesign using the dependability criterion is a stochastic optimization problem. An example problem with three stochastic variables and two design variables is presented to illustrate these procedures. Copyright © 1975 American Institute of Chemical Engineers

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Drag Reduction In Solid‐Fluid Systems, I. Radin, J. L. Zakin, Gary Kent Patterson Jan 1975

Drag Reduction In Solid‐Fluid Systems, I. Radin, J. L. Zakin, Gary Kent Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

Pressure drop measurements were made on a variety of dilute solid‐liquid suspension systems in order to study the effects of particle shape and size, concentration, fluid viscosity, and tube diameter on friction factor. The central objective was to determine under what conditions drag reduction would occur. Copyright © 1975 American Institute of Chemical Engineers

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Diffusion Coefficients Of N-Heptane And N-Decane In N-Alkanes And N-Alcohols At Several Temperatures, James W. Moore, Robert M. Wellek Apr 1974

Diffusion Coefficients Of N-Heptane And N-Decane In N-Alkanes And N-Alcohols At Several Temperatures, James W. Moore, Robert M. Wellek

Chemical and Biochemical Engineering Faculty Research & Creative Works

The diffusion coefficients of the solutes n-heptane and n-decane were measured in the series of alkane solvents n-hexane through n-decane and in the alcohol solvents n-hexanol and n-heptanol. Mutual and self-diffusivities in most cases were measured at the temperatures of 20°, 25°, 30°, and 40°C. Concentrations of the diffusion species were in the infinitely dilute region. An unsteady state porous frit technique was used with carbon-14 tagged diffusion species. The diffusion coefficients measured were compared with various liquid diffusivity prediction correlations. © 1974, American Chemical Society. All rights reserved.

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Film Formation On Anodically Polarized Lead, H. Vaidyanathan, Ram A. Narasagoudar, Thomas J. O'Keefe, William Joseph James, James W. Johnson Jan 1974

Film Formation On Anodically Polarized Lead, H. Vaidyanathan, Ram A. Narasagoudar, Thomas J. O'Keefe, William Joseph James, James W. Johnson

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Permeability Of Selected Gases Through Radio‐Frequency Plasma‐Polymerized Films, B. Suryanarayanan, J. (Jerry) J. (James) Carr, K. (Kenneth) G. Mayhan Jan 1974

Permeability Of Selected Gases Through Radio‐Frequency Plasma‐Polymerized Films, B. Suryanarayanan, J. (Jerry) J. (James) Carr, K. (Kenneth) G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Intrinsic Viscosity Studies Of Linear Polyethylene Fractions In Good And Poor Solvents, J. S. Chiang, J. L. Zakin, Kenneth G. Mayhan Jan 1974

Intrinsic Viscosity Studies Of Linear Polyethylene Fractions In Good And Poor Solvents, J. S. Chiang, J. L. Zakin, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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The Density Determination Of Rf Plasma Polymers, W. W. Knickmeyer, B. W. Peace, Kenneth G. Mayhan Jan 1974

The Density Determination Of Rf Plasma Polymers, W. W. Knickmeyer, B. W. Peace, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Modified One‐At‐A‐Time Optimization, Marshall E. Findley Jan 1974

Modified One‐At‐A‐Time Optimization, Marshall E. Findley

Chemical and Biochemical Engineering Faculty Research & Creative Works

An optimization method has been developed that searches one variable at a time under the conditions that previously searched variables are at their approximate optimum and variables to be searched later are constant. This method provides the optimum and also information on the effects of the variables. The method is based on the Partan and Powell methods and on assuming linear partial derivatives of the objective function with respect to any given variable. The procedure involves searching each variable separately with other variables either constant or varied so that they remain at their estimated optimum for the given conditions. This …

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The Anodic Dissolution Of Tin In Acidic Chloride Solutions, James W. Johnson, E. C. Liu Jan 1974

The Anodic Dissolution Of Tin In Acidic Chloride Solutions, James W. Johnson, E. C. Liu

Chemical and Biochemical Engineering Faculty Research & Creative Works

The anodic dissolution of Sn in acidic chloride solutions (pH = -2.0 to 2.9) was studied at 25 °C. The apparent valence of the dissolving ions varied from about 0.4 to 2.4, and was a function of both electrolyte and c.d. The complexing of Sn2+ by Cl- had an important influence, with SnCl-3 apparently being the dominant product. A reaction sequence is proposed involving the stepwise oxidation of Sn, accompanied by reaction with Cl-. © 1974.

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Structure Of High-Internal-Phase-Ratio Emulsions, K. J. Lissant, B. W. Peace, S. H. Wu, K. (Kenneth) G. Mayhan Jan 1974

Structure Of High-Internal-Phase-Ratio Emulsions, K. J. Lissant, B. W. Peace, S. H. Wu, K. (Kenneth) G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Letters To The Editor, J. T. Mason, Orrin K. Crosser, Robert D. Gunn, C. Judson King Jan 1973

Letters To The Editor, J. T. Mason, Orrin K. Crosser, Robert D. Gunn, C. Judson King

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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A Study Of Medium And High Internal Phase Ratio Water/Polymer Emulsions, Kenneth J. Lissant, Kenneth G. Mayhan Jan 1973

A Study Of Medium And High Internal Phase Ratio Water/Polymer Emulsions, Kenneth J. Lissant, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Medium and high internal phase ratio water/polymer emulsions were studied utilizing scanning electron microscope techniques. Results are reported for the geometry and distribution of droplets for water/polymer ratios from 1 1 to 9 1. Electron micrographs confirm those models which predicts polyhedral droplet formation at high internal phase ratios. © 1973.

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Polymers From The Hydrolysis Of Tetraethoxysilane, B. W. Peace, Kenneth G. Mayhan, J. F. Montle Jan 1973

Polymers From The Hydrolysis Of Tetraethoxysilane, B. W. Peace, Kenneth G. Mayhan, J. F. Montle

Chemical and Biochemical Engineering Faculty Research & Creative Works

The hydrolysis of tetraethoxysilane was studied under various solvent and temperature conditions. A method was developed by which reaction rates can be measured even in the presence of alcohols other than ethanol. The structures of the resulting polymers were dependent upon the reaction conditions employed, those formed at high temperature being highly condensed materials. © 1973.

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A Quantitative Analysis By Emission Spectroscopy Of The Metallic Constituents Of Biological Samples After Treatment By A Carcinogenic Agent, Charles R. Frydrych Dec 1972

A Quantitative Analysis By Emission Spectroscopy Of The Metallic Constituents Of Biological Samples After Treatment By A Carcinogenic Agent, Charles R. Frydrych

Masters Theses

No abstract provided.

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A Study Of Homogeneous Catalysis By High-Pressure Kinetics. The Mechanism Of Catalysis Of A Diels—Alder Reaction, Bruce E. Poling, Charles A. Eckert Nov 1972

A Study Of Homogeneous Catalysis By High-Pressure Kinetics. The Mechanism Of Catalysis Of A Diels—Alder Reaction, Bruce E. Poling, Charles A. Eckert

Chemical and Biochemical Engineering Faculty Research & Creative Works

The application of high-pressure kinetics as a tool to investigate the detailed mechanism of catalysis of a reaction is demonstrated. Activation volumes have been determined for the Diels-Alder addition of 2, 3-dimethylbutadiene to n-butyl acrylate, both uncatalyzed and catalyzed with AICI3. Also, partial molal volumes of reactants and products have been measured. From these data it is shown that the volume profile along the reaction coordinate is similar for both the catalyzed and uncatalyzed reactions. Further, both reactions proceed by a concerted one-step mechanism through a compact transition state with maximum accumulation of double bonds. Thus, the role of the …

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Discussion, A. G. Fabula, Gary Kent Patterson Jan 1972

Discussion, A. G. Fabula, Gary Kent Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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