Chemical Engineering Commons^™

Mass Transfer At The Edge Of A Rotating Disk, Jeffrey Malcolm Cohen

Chemical and Biological Engineering ETDs

A different approach to the problem of mass transfer to a rotating disk, employing less restrictive assumptions, has been undertaken to quantify the phenomenon of mass transfer at the disk's edge. Experimental work in support of theor­etical conjectures was performed as part of this work.

In order to include the effect of mass transfer at the edge on mass transfer to the entire disk, the equation of convective diffusion was solved in two dimensions over a region that extended beyond physical projection of active area of the disk. A synthesis of experimental results and theoret­ical considerations was used to specify …

Concentrated Organic Separations By The Cyclic Indirect Freezing Process, Jeffrey Carl Miles

Chemical and Biological Engineering ETDs

This study demonstrates the technical feasibility of purifying concentrated organic solutions by the cyclic indirect freezing process with in-situ washing and in-situ melting operations. The key to a successful purification in the freezing process is a near plug flow displacement of unfrozen liquor from the bed in an in-situ washing operation. To be successful, a freezing step has to be initiated uniformly and a high permeability bed has to be formed uniformly throughout the freezing conduits. In the study, a nucleation technique based on pressure induced supersaturation has been used to accomplish a uniform initiation and a pressure induced freezing …

Ocean Thermal Energy Conversion By Using A Solidification Melting Cycle, Wen Liang Lin

Chemical and Biological Engineering ETDs

An OTEC (Ocean Thermal Energy Conversion) power plant uses warm surface seawater (24° C - 28° C) as a heat source and deep cold seawater (4° C - 7°C) as a heat sink. With this temperature difference, a heat engine which delivers either mechanical or electric power can be con­structed. There are some limitations and problems of evaporators and condensers to be used in a closed Rankine cycle OTEC plant which have seriously limited the applicability of this concept. This study proposed a process using the S/L engine---a heat engine that utilizes a working medium undergoing solidification and melting operations. …

The Fracture Toughness Of Steel-Aluminum Deformation Welds, Charles Ellis Albright Jr

Chemical and Biological Engineering ETDs

A study of the fracture toughness (in this case, Gic) of steel-aluminum deformation welds using a specially developed double cantilever beam fracture toughness specimen is presented. Welds made at 350C were heat treated at 360, 380, 400, 420 and 440 C.

An intermetallic reaction product layer of Fe2Al5 is formed at the steel-aluminum interface with increasing heat treating temperature and time by a process of nucleation and growth of discrete particles. A transition in toughness from a higher average Gic value (6097 N/m) to a very low average Gic value (525 N/m) is observed. The decrease in toughness is accomplished …

An Investigation Into The Transport Properties And Kinetic Parameters Of Single Coal Particles During Devolatilization, Gregory Forrest Roach

Chemical and Biological Engineering ETDs

This study focuses on the devolatilization step that occurs in the process of coal gasification. This is a key economic step for both the Lurgi synthetic natural gas process and the in-situ gasification that are being proposed for New Mexican coals. The findings of this study may be used by industry to improve the design and operation of these processes.

The work presented is an investigation into the transport properties and kinetic parameters that govern the extent of pyrolysis for single particles of subbituminous coal from the San Juan Basin in north-west New Mexico. The unique feature of this work …

A Simple, Inexpensive Spinning-Drop Interfacial Tensiometer, Humoud S. Al-Rabiah

Chemical and Biological Engineering ETDs

A spinning-drop interfacial tensiometer was designed, built, and tested. The device is very simple, inexpensive to build, and easy to operate compared with other spinningdrop tensiometers.

The tensiometer measures the interfacial tension of liquid-liquid or liquid-vapor systems. Interfacial tensions of three systems were measured to test the device: water-heptane, glycerol-heptane, and glycerol-air.

Experimental results agree with literature values within one percent for the glycerol-heptane system. The variations among the values for the liquid-liquid systems at different rotational speeds are within six percent. Repeated experiments with different drop sizes show that drop size of the glycerol-air system may affect the results. …

Desublimation Of Water Vapor At Low Pressure And Evaporative Freezing Of Seawater, Sun Sea Pao

Chemical and Biological Engineering ETDs

The Vacuum-Freezing Vapor-Desublimation and High Pressure Ice-Melting Process has been developed since 1972. In 1976, Mr. T. C. Chung finished a theoretical study of Low Pressure Water Vapor Desublimation Operation. The writer was a co-worker of Mr. Chung, and had worked with him for the study for four months. The information collected in Mr. Chung's thesis was borrowed and edited as Chapters 1 and 2 in the present thesis. Mr. Chung's theory predicts the rate of water vapor desublimation as a function of the difference between operating temperature and desublimer wall temperature. In the present thesis, experimental rates of desublimation …

A Study Of A Buoyancy Balanced Gas-Liquid Contacting System, Jaw-Ruey Leu

Chemical and Biological Engineering ETDs

In a conventional gas-liquid contacting system that provides a long gas-liquid contact time, a pressurized gas is released at the bottom of a pool of liquid to form gas bubbles; the bubbles move upward through the liquid and break at the surface of the liquid. A large amount of work is spent in pressurizing the gas. Even though it is theoretically possible to recover work from rising bubbles, a work recovery scheme has not been incorporated into a conventional system.

A buoyancy-balanced gas-liquid contacting system concept has recently been introduced. The system comprises two processing zones filled with a liquid, …

Separation Of Organic Solutions By The Indirect Fractional Solidification Process With In-Situ Washing And Melting Operations, Juiuun-Perng Chiang

Chemical and Biological Engineering ETDs

The main objective of the present thesis study is to experimentally investigate the feasibility of purifying both dilute and concentrated organic solutions by the indirect freezing process with in-situ washing and melting operations under industrially practicable operating conditions. The smooth deposit approach and the dendritic deposit approach are respectively used in separating dilute solutions and concentrated solutions and small ΔT's for heat transfer, less than 3 °C, have been used throughout the study.

A convenient ultrasonic device and easily practicable operating procedures for nucleating slightly super-cooled liquids have been developed. Several freezer­melter systems incorporating the new ultrasonic devices have been …

Reactivity And Kinetic Comparison Of Large Single New Mexican And South African Subbituminous Coal Particles, Wendall Gerald Stoddart

Chemical and Biological Engineering ETDs

This study focuses on one aspect of coal gasification; that is, devolatilization of large single coal particles. Devolatilization is an important and key economic step in the overall gasification process. From a commercial standpoint for New Mexico, there are two processes in the field of coal gasification of importance: the Lurgi synthetic natural gas process and in-situ gasification. Since both the Lurgi and in-situ processes treat rather large particles of coal, the findings in this study might be used by industry to improve the design and operation of these processes. The work presented is a study and comparison of the …

Modeling Of A Fossil-Fired Power Plant For Real-Time Simulation, Robert Douglas Busch

Chemical and Biological Engineering ETDs

Computer simulation of complex physical systems can be a useful technique in analyzing the multitude of interactions occurring in such systems. Real-time modeling of power plants is particularly useful in operator training and engineering research programs. Towards this end, a small-scale simulator has been developed using a dedicated minicomputer. Major components of a drum-type fossil-fired power plant were modeled using first principle, physical equations, and then the component modules were interconnected to form the simulation package. Support routines were written to provide real-time operation, periodic data storage, continuous data display, interrupt capabilities, and manipulation of control variables. The package presently …

The Condensation Of Vapor On A Horizontal Rotating Square Tube., Suresh Chandra

Chemical and Biological Engineering ETDs

Heat transfer measurements were made for steam vapor condensing at one atmosphere on the outer surface of a horizontal square tube with a side of one inch, when rotated at between O and 1950 rpm. The Froude number (FR) was based on the side length. Three distinct heat-transfer regimes were observed and are correlated with FR. The first is gravita­tion controlled condensate flow when FR is less than 2.0 and the condensing film heat-transfer coefficient decreases. When 2.0

Kinetics And Dynamics Of Continuous Crystallization, Karichangal C. Parthasarathy

Chemical and Biological Engineering ETDs

A design correlation is presented for the prediction of steady state product size distributions resulting from a continuous crystal­lizer, based upon a single experimental determination. This has been accomplished by the definition of a new parameter called the "degree of crystallization," which has been related to the experimental nuclea­tion and growth rates in a salting-out crystallizer. The correlation resulted from the detection of variations in the suspension density of the mother liquor which has previously been assumed constant in cer­tain power law models. The degree of crystallization has also been described in terms of dimensionless number, length and area moments …

Continuous Crystallization Of High Explosives, Larry E. Hatler

Chemical and Biological Engineering ETDs

Nitroguanidine (NQ) is a high explosive which is commercially available in low bulk density form (0.20 to 0.30 gms/cm³). This low bulk density limits its usefulness as an explosive. High bulk density NQ can be produced from a NQ-N, N-dime-thylformamide-Versamid 125 system when crystallized in a mixed suspension mixed product removal crystallizer. Bulk densities ranged from 0.92 to 1.05 gms/cm³ for the operating conditions used. The effect of agitator speed, growth rate, and solids concentration on nucleation rates was determined using a multiple linear regression technique. The resulting equation is: B₀ = 0.19 (RPM) ^1.54 (G) …

Dispersion In Laminiar Flow Of Non-Newtonian Fluids, Subhash N. Shah

Chemical and Biological Engineering ETDs

In the present investigation, Taylor's analysis of the dispersion of solutes in laminar flow of a Newtonian fluid through a circular tube was extended to the case of a non-Newtonian Eyring model fluid. A new approach was taken to solve the convective diffusion equation for the Eyring model fluid. This approach incorporates the use of the dimensionless longitudinal pressure gradient and the mean velocity to obtain the dimensionless concentration. Using an approach similar to that of Taylor, a solution of the diffusion equation was obtained for quantities such as the dimensionless concentration, mean concentration, and effective dispersion coefficient as a …

An Analysis Of The Behavior Of A Non-Newtonian Fluid In A Flow Reactor, Asahiro Ahagon

Chemical and Biological Engineering ETDs

Velocity, temperature and concentration profiles were derived for non-Newtonian laminar flow of a reacting species in a tubular reactor. The equation of motion based on a temperature dependent power-law fluid model and the energy equation with internal heat generation caused by a first order chemical reaction were coupled and solved simultaneously using numerical methods to yield the profiles. The assumptions made in this study were: constant physical properties of the fluid (density, thermal conductivity and heat capacity). fully developed flow, wall temperature and negligible diffusion. Compartmentalized calculations resulted in velocity, temperature and reactant concentration profiles for both the axial and …

An Experimental Study On Heat Transfer Coefficient For Carbon Laden Gas, Jacob Chi-Kwong Huang

Chemical and Biological Engineering ETDs

Abstract

A complete carbon black pilot plant was employed in this study. Carbon laden gas was produced in a fur­nace and introduced into the outer pipe of a heat ex­changer. Air, at the same time, was introduced into

the inner pipe of the heat exchanger cocurrently with the carbon laden gas. Thus, heat, with temperature dif­ference as driving force, would transfer from the car­bon laden gas to the air stream. The temperatures along the two streams were measured by iron-constantan ther­mal couples and recorded by a multi-reading temperature

recorder. Air supply and fuel (C3H8) supply were intro­duced into the furnace …

Preparation Of Metallic Oxide Aerosols By Vaporization And Degradation Of Organic Compounds, Tom B. Larsen

Chemical and Biological Engineering ETDs

Simple, dependable methods for the generation of aerosols are necessary to many forms of research. Specifically inhal­ation research has a requirement for sub-micron sized insoluble particles.

Two different methods for the production of oxide aerosols from vaporizable compounds were tried. The first method, a mod­ification of the Rapaport-Weinstock generator (R3), consisted of nebulization of a solution into a droplet mist. Next the drop­lets were vaporized, and condensation nuclei formed from the nonvaporizable impurities in the solution. The vapor was allowed to condense on the nuclei in a relatively large chamber, then the resulting liquid droplet aerosol was dried and converted …

Wetting Of Carbon Filaments By Organic Liquids, Linden Tewes Halstead

Chemical and Biological Engineering ETDs

The object of this was to find the factors controlling the rate of wetting of carbon filaments by organic liquids. To carry out this study, the factors affecting the wetting of surfaces, such as the surface tension of liquids, and the contact angle formed at the liquid-vapor-solid boundary of a three phase system were discussed. At the same time, the anomalies with respect to contact angle, such as that relating to advancing and receding contact angles to dynamic angles was considered. As complimentary information, the methods used to obtain carbon and graphite filaments from cellulose and molten pyrolysis products were …

A Study Of The Reduction Of Nickel Oxide Single Crystal By Hydrogen In A High Vacuum System., Jong In Joung

Chemical and Biological Engineering ETDs

Wafers of well-characterized nickel oxide single crystal, with (110) faces, were etched in hydrochloric acid and reduced by hydrogen in a high vacuum system. Reduction took place at temperatures of 280-310°C and pressures of 1.0-1.3 torr. The reduced wafers were replicated by carbon film and the replicas were examined by an electron microscope.

A series of reduction patterns at various stages of surface change were obtained. After a period of incubation, hemispherical metallic nickel particles, about 400 A in diameter, appeared on the parent nickel oxide surface. The number of hemispheres increased but the size of the hemispheres did not …

Fabrication Of The Pewee Nozzle; Brazing Nozzles For Rockets Powered By Nuclear Reactors, William C. Turner

Chemical and Biological Engineering ETDs

This thesis describes the steps taken to develop an improved process for brazing nozzles for nuclear-powered rockets. It defines the state of the art prior to this work. It gives an evaluation of the brazing alloys available for use. It shows the methods employed to develop the use of positive fixturing. It describes the use of full-scale sectors to refine processing. This thesis also describes the use of such new processing techniques in the successful production of two nozzles. Gold-nickel-palladium brazing alloys are used. Vacuum atmosphere performs superbly. Bands are used to hold U-tubes into slots in the shell. Problems …

Size Distribution Analysis Of Carbon Black By Andreason Pipette Method, Natarajan Mani

Chemical and Biological Engineering ETDs

There have been several methods commonly used for measuring particle size distribution of particulate systems in the subsieve region, i.e., less than 45 microns. Of the many indirect procedures of particle size analysis, sedimentation methods are among the most satisfactory and most widely used. - The value and appeal of sedimentation techniques are twofold: (1) the equipment required is simple and (2) a wide range of sizes may be measured readily with considerable accuracy and reproducibility. These techniques utilize the dependence of the falling velocities of particles on their size.

This study widely encompasses the various factors involved in the …

A Computer Multistage Optimization Method On Ethane Decomposition, Jonathan K. Ma

Chemical and Biological Engineering ETDs

The prediction of conversions and product distributions under various conditions is of prime interest in the process design of an optimum reactor. This is a very difficult task when a complex reaction is under consideration; since reactions take place simultaneously the relationship of the individual reaction and the over-all product distribution and their correlation with the control variables are hard to define. This study is an application of the free radical mechanism of the thermal decomposition of ethane to calculate the product distribution. Since this is an endothermic reaction, the temperature profile is the control variable. The relationship between the …

Joining Graphite To Graphite With Transition Metal Foils, Donald James Sandstrom

Chemical and Biological Engineering ETDs

A study has been undertaken to determine the relationship of metallic-foil joining and joining parameters to the strength of joints in a high-quality extruded nuclear graphite. The materials chosen for investigation as joining materials on the graphite of interest were considered to be representative of the Group IVA, VA, and VIA transition metals and iron. The parameters used for joining yielded either a fully diffused joint, which was not temperature-limited with respect to service conditions or a continuous-carbide-interface joint, which was temperature -limited. The metal chosen from Group IVA for joining was zirconium in the form of 0.0005 in. -thick …

The Effects Of Additive And Surface-Active Agents On Interphase Mass Transfer In A Solid-Liquid System, Gim Tan

Chemical and Biological Engineering ETDs

Study of the effects of contaminants on interface mass transfer in fluid-fluid systems has been the object of many recent theoretical and experimental investigations. The investigators’ common hope of finding a unified theory to explain the action of surfactants has not been accomplished. Instead, many different and conflicting theories have been advanced to explain the experimental results. The present investigation was undertaken to study the effects of contaminants on liquid phase mass transfer in a solid-liquid system. The theoretical and experimental model chosen for the present case was that of a flat disk rotating in a quiescent fluid. The rotating-disk …

Recovery Of Copper By Liquid Ion-Exchange, Bipinchandra V. Vora

Chemical and Biological Engineering ETDs

In 1955 the United States Atomic Energy Commission declassified certain information regarding solvent extraction (1). Since then the liquid ion-exchange process, sometimes known as liquid-liquid extraction, has become significant method tor the recovery of pure metals from low grade ores. This process has achieved its greatest success in the uranium industry (2).

Conversion Of Parahydrogen To Orthohydrogen, George A. Winkler

Chemical and Biological Engineering ETDs

Heisenberg (53) and Hund (57) postulated the existence of two modifications of hydrogen. This occurred as a result of Heisenberg's previous explanation of the existence for orthohelium and parahelium using quantum theory. From analogous considerations, he and Hund asserted that hydrogen was a mixture of two gases. Dennison (28) applied their theories to explain the falling off of the rotational specific heat of hydrogen. This had been observed by Eucken (34) in 1912. In 1928, Giaque and Johnston (45) held gaseous hydrogen at 85°K for six months. On liquefaction they found a detectable difference in vapor pressure. They stated that …

Vapor Liquid Equilibria Of The Isopropanol-Isopropylacetate-Water System, Amin Zavosh

Chemical and Biological Engineering ETDs

The separation of isopropylacetate from a ternary mixture of isopropanol, isopropylacetate and water by azeotropic distillation requires reliable and thermodynamically consistent vapor-liquid equilibrium data. By using a single experimental vapor-liquid equilibrium datum point for each of the related binaries of the above system, it is possible to determine the binary constants of some of the integrated forms of the Gibbs-Duhem equation such as the Van Laar or Margules equation. The binary constants can be used in the ternary forms of the above equations and in conjunction with the definition of activity coefficient to generate approximate vapor-liquid equilibrium data over the …

Characterization Of Synthetic Resins Used In Graphite Extrusion Process, Charles I. Fairchild

Chemical and Biological Engineering ETDs

Six furan resins and one epoxy resin were used in tests to determine coking values and gas evolution characteristics of the resins. The same resins, except the epoxy, were used as binders in extruded graphite rods to determine environmental factors affecting the coked density of the rods.

Coking values of the resins containing three different activators were determined by measuring residue remaining after heat treatment to 850° C. Coking values 54-56% were obtained with 8 phr to toluenesulfonic acid actiator.

Gas evolution curves were obtained by measurement of pressure rise in a constant volume apparatus during heating to 300° C …

Evaluation Of The Thermal Properties Of Plastic Laminates, Luciano Sedillo

Chemical and Biological Engineering ETDs

To insure the proper application of newly developed materials, it is necessary to evaluate their physical and chemical properties. In the case of plastic laminates for use as heat barrier material, thermal diffusivity is an important property. Thermal diffusivity is the parameter which governs the rate of temperature change through a material. Its value depends upon the chemical composition and the physical structure of the material and its temperature.