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Chemical and Biochemical Engineering Faculty Research & Creative Works

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Articles 751 - 780 of 821

Full-Text Articles in Chemical Engineering

Application Of Generalized Geometric Programming In Preliminary Plant Design, Dennis R. Hoerner, Orrin K. Crosser Apr 1981

Application Of Generalized Geometric Programming In Preliminary Plant Design, Dennis R. Hoerner, Orrin K. Crosser

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study utilizes a primal based generalized geometric programming algorithm for the optimal design of a model absorber-stripper process. The GGP algorithm reduces the generalized geometric program to a convex, linear program by two sequential condensation procedures and a logarithmic transformation. Although inactive Inequality constraints and arbitrary variable bounds were easily accommodated by the algorithm, considerable effort was required to activate the inequality constraints which required an equality condition. The GGP algorithm converged to a local minimum from arbitrary starting points for approximately 60% of the trials. © 1981, American Chemical Society. All rights reserved.

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Thermodynamic Properties From A Cubic Equation Of State: Avoiding Trivial Roots And Spurious Derivatives, Bruce E. Poling, Edward A. Grens, John M. Prausnltz Jan 1981

Thermodynamic Properties From A Cubic Equation Of State: Avoiding Trivial Roots And Spurious Derivatives, Bruce E. Poling, Edward A. Grens, John M. Prausnltz

Chemical and Biochemical Engineering Faculty Research & Creative Works

A simple method is presented to find and avoid trivial roots and spurious derivatives for a cubic equation of state. The method's utility is demonstrated with some illustrative distillation calculations. © 1981, American Chemical Society. All rights reserved.

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Propane-Carbon Dioxide And Propylene-Carbon Dioxide Mixture Adsorption In 5a Molecular Sieves, Orrln K. Crosser, Bui V. Hong Oct 1980

Propane-Carbon Dioxide And Propylene-Carbon Dioxide Mixture Adsorption In 5a Molecular Sieves, Orrln K. Crosser, Bui V. Hong

Chemical and Biochemical Engineering Faculty Research & Creative Works

Measurements of the adsorption on 5A molecular sieves have established that, at 1 atm and 24.0 °C, both systems, propane-carbon dioxide and propylene-carbon dioxide, form Ideal solution adsorbed phases. Total mass adsorbed ranges from 112 to 207 mg/g of sorbent for propane-carbon dioxide and from 130 to 207 mg/g of sorbent for propylene-carbon dioxide. © 1980, American Chemical Society. All rights reserved.

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Analysis Of Batch Scraped Surface Heat Exchange, Orrin K. Crosser, K. Y. Park Jan 1980

Analysis Of Batch Scraped Surface Heat Exchange, Orrin K. Crosser, K. Y. Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Ethylene Process Optimization. Constraint Relaxation And Bounds Adjustment, Kenneth R. Jinkerson, James L. Gaddy Oct 1979

Ethylene Process Optimization. Constraint Relaxation And Bounds Adjustment, Kenneth R. Jinkerson, James L. Gaddy

Chemical and Biochemical Engineering Faculty Research & Creative Works

Heavily constrained, mixed integer optimization problems present a difficult test for optimization algorithms. This paper examines optimization of the ethylene process (from ethane) using a flowsheet simulation model and the adaptive random search. Optimization resulted in an improvement in annual earnings of $1.15 MM over the usual ethylene process design. This process has both continuous and discrete variables and has sensitive implicit constraints in the pyrolysis furnace. The search efficiency was found to be improved by relaxing these constraints early in the search and then restoring the constraints as the optimum is approached. The search efficiency was also improved by …

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Film Boiling Of Freon 113, Normal Pentane, Cyclopentane And Benzene From Cylindrical Surfaces At Moderate Pressures, G. J. Capone, Efton Park Jan 1979

Film Boiling Of Freon 113, Normal Pentane, Cyclopentane And Benzene From Cylindrical Surfaces At Moderate Pressures, G. J. Capone, Efton Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

An investigation of film boiling heat transfer in saturated pools of liquid Freon 113, normal pentane, cyclopentane and benzene was conducted. The fluids were boiled from copper, cylindrical heat transfer surfaces 0.0762m (3 in) long, and 0.01397,0.01905 and 0.0254m (0.55,0.75 and 1.0 in) in diameter. The data covers a moderate range of pressures up to 1.67 (10)6 N/m2 (242.5 psia). The experimental data are compared with existing film boiling correlations. The existing film boiling correlations were found to be inadequate in predicting heat-transfer coefficients for the conditions of this investigation. © 1979.

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Plasma Polymerization Of Tetrafluoroethylene. Iii. Capacitive Audio Frequency (10 Khz) And Ac Discharge, N. (Nicholas) C. Morosoff, H. Yasuda, E. S. Brandt, C. N. Reilley Jan 1979

Plasma Polymerization Of Tetrafluoroethylene. Iii. Capacitive Audio Frequency (10 Khz) And Ac Discharge, N. (Nicholas) C. Morosoff, H. Yasuda, E. S. Brandt, C. N. Reilley

Chemical and Biochemical Engineering Faculty Research & Creative Works

The plasma polymerization of tetrafluoroethylene (TFE) is studied in a capacitively coupled system with internal electrodes using a 10 kHz (af) and a 60 Hz (ac) source. The emphasis is on identifying conditions that are compatible with continuous coating of plasma polymer on a substrate moving through the center of the interelectrode gap. Operation at a pressure below 100 mTorr is most favorable for deposition of a substantial portion of the plasma polymer on this substrate. Plasma polymer deposited in this way is characterized by ESCA and by deposition rate data and compared to that deposited using rf power in …

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Plasma Polymerization Of Tetrafluoroethylene. Ii. Capacitive Radio Frequency Discharge, N. (Nicholas) C. Morosoff, H. Yasuda, E. S. Brandt, C. N. Reilley Jan 1979

Plasma Polymerization Of Tetrafluoroethylene. Ii. Capacitive Radio Frequency Discharge, N. (Nicholas) C. Morosoff, H. Yasuda, E. S. Brandt, C. N. Reilley

Chemical and Biochemical Engineering Faculty Research & Creative Works

The plasma polymerization of tetrafluoroethylene (TFE) is studied in a capacitively coupled system with internal electrodes using radio frequency (13.56 MHz) power. The emphasis is on identifying conditions that are compatible with continuous coating of plasma polymer on a substrate moving through the center of the interelectrode gap. At high pressure (500 mTorr), deposition of plasma polymer is primarily on the electrodes rather than on a substrate placed midway between electrodes. Glow is observed in only part of the interelectrode gap at low powers and fills the gap only at high power levels. The use of a magnetic field effects …

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Mechanical Degradation Of High Molecular Weight Polymers In Dilute Solution, J. F.S. Yu, J. L. Zakin, Gary Kent Patterson Jan 1979

Mechanical Degradation Of High Molecular Weight Polymers In Dilute Solution, J. F.S. Yu, J. L. Zakin, Gary Kent Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

The mechanical shear degradation of polydisperse Poly isobutene and monodisperse polystyrene in oils of different viscosities in the concentration range of 0.1% to 1% was studied using a high‐shear concentric cylinder viscometer under laminar and uniform well‐defined shear field conditions. Molecular weight distributions (MWDs) were measured by gel permeation chromatography (GPC). Degradation of polydisperse Poly isobutene solutions narrows the distributions principally through the breaking down of large molecules. Degradation of monodisperse polystyrene broadens the distributions at lower shear stress. At higher shear stresses, the distributions do not broaden as much but are still broader than those of the original polymer. …

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Transport Of Oils As Oil-In-Water Emulsions, J. L. Zakin, R. Pinaire, M. E. Borgmeyer Jan 1979

Transport Of Oils As Oil-In-Water Emulsions, J. L. Zakin, R. Pinaire, M. E. Borgmeyer

Chemical and Biochemical Engineering Faculty Research & Creative Works

Turbulent flow pressure drop measurements were made for various concentrated oil-in-water emulsions which exhibit non-Newtonian behavior. The effects of oil viscosity, temperature and oil concentration on specific energy loss were evaluated. Measured turbulent friction factors consistently fell below those predicted by the Dodge and Metzner friction factor correlation, probably due to viscoelastic effects of the emulsion. Several polymer and surfactant drag reducers were tested in these emulsions, and high molecular weight polyacrylamides were found to be the most effective in further reducing pumping energy losses. The effectiveness of the polymer additives decreased with time during pump circulation. © 1979 by …

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Nucleate Boiling Of N-Pentane, N-Hexane And Several Mixtures Of The Two From Various Tube Arrays, K. W. Wall, Efton Park Jan 1978

Nucleate Boiling Of N-Pentane, N-Hexane And Several Mixtures Of The Two From Various Tube Arrays, K. W. Wall, Efton Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Variable Elimination For Optimization With Difficult Explicit Inequality Constraints, R. C. Kelahan, J. L. Gaddy Jan 1978

Variable Elimination For Optimization With Difficult Explicit Inequality Constraints, R. C. Kelahan, J. L. Gaddy

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Vapor Pressures For The System Isobutane-Isobutylene-N-Butane, José A. Martünez-Ortiz, David B. Manley Jan 1978

Vapor Pressures For The System Isobutane-Isobutylene-N-Butane, José A. Martünez-Ortiz, David B. Manley

Chemical and Biochemical Engineering Faculty Research & Creative Works

New experimental vapor pressures for the ternary system composed of Isobutane-isobutylene-n-butane from 40 to 160 °F and 20 to 160 psia are presented. The data have an estimated average accuracy of 0.04%. The pure component data are compared with existing data from the literature. © 1978, American Chemical Society. All rights reserved.

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Direct Solution Of The Isothermal Gibbs-Duhem Equation For Multicomponent Systems, José A. Martinez-Ortiz, David B. Manley Jan 1978

Direct Solution Of The Isothermal Gibbs-Duhem Equation For Multicomponent Systems, José A. Martinez-Ortiz, David B. Manley

Chemical and Biochemical Engineering Faculty Research & Creative Works

The numerical solution of the relative volatility form of the isothermal Gibbs-Duhem equation for multicomponent systems Is carried out by a relaxation technique for two ternary systems at five different temperatures. This direct method of solution eliminates calculating and differentiating the excess Gibbs free energy as required by other indirect methods. © 1978, American Chemical Society. All rights reserved.

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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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