Browsing by Author "Deans, H. A. (Harry A.)"

Now showing 1 - 9 of 9
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    Application of bubble columns to gas-liquid chromatography
    (1965) Owen, George Rice; Deans, H. A. (Harry A.)
    When a gas bubble rises through a liquid in a tube of suitable internal diameter, the thin liquid film flowing past the bubble approaches equilibrium with the contents of the bubble. If perfect mixing within the bubble is assumed, all the gas contacts all the liquid in the column. This is the essential requirement for a quantitative chromatographic situation. This work is an evaluation of the practicability of such a bubble column as a chromatographic device. As a test of the system, the equilibrium K-value for ethane in n-decane at 75°F and infinite dilution was obtained experimentally and compared with literature values to evaluate the validity of the method. The results agreed very well with literature data, and it was concluded that further development of the technique is well justified.
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    Determination of thermal properties of porous catalyst particles
    (1962) Park, Efton Lilborn; Deans, H. A. (Harry A.)
    An unsteady state technique for the determination of mean thermal diffusivity of porous cylindrical catalyst particles was investigated. A calorimetric procedure was used to determine heat capacity of the pellets, so that thermal conductivity could be calculated. The experimental apparatus and procedures were evaluated by determining thermal conductivity and thermal diffusivity of "teflon" and five porous catalyst samples at three temperature levels.
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    Determination of vapor-liquid equilibria by horizontal bubble column chromatography
    (1968) Perilloux, Charles J. (Charles Joseph); Deans, H. A. (Harry A.)
    When a series of closely spaced gas bubbles flows with the surrounding liquid in a small tube, the. gas velocity will be greater than that of the liquid due to the thin stationary liquid film along the tube walls. This velocity separation meets a prime requirement for a chromatographic system. If a pulse of radioactive tracers is injected into such a system, the retention time of each tracer component will depend only on the gas and the liquid velocities, the relative amounts of liquid and vapor in the column, and the vapor-liquid equilibrium K value of the component. Thus, a bubble column can be used to determine K values. This work determined the K value of ethane at 74 °F and one atmosphere at infinite dilution in the helium-n-decane system to be 26.6 ± 2.1. This compares favorably with data taken by static means. The peak dispersion coefficient increased with the square of the bubble velocity. The film thickness vs. velocity agreed well with theory. The method has been extended in theory to the general case of n components with each component present in both phases.
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    Investigation of critical points using a dynatrol detector
    (1962) Brody, Gerald Lawrence; Deans, H. A. (Harry A.)
    The critical parameters for propane were determined using an Automation Products Dynatrol Detector. The Dynatrol is a system of coupled vibrating masses, whose resonant frequencies are functions of the density of the fluid surrounding one of the masses, namely the paddle which can be immersed in a test fluid. If the paddle is partly surrounded by liquid and partially by vapor, the resonant frequencies are measures of liquid level. An experimental cell was filled at room temperature with propane such that two phases existed. The paddle of the Dynatrol was located in the cell such that, as the cell was rotated, the paddle was immersed first in the vapor phase, next in the liquid phase, and finally partially in both phases. The temperature of the cell was raised and the amount of propane in the cell adjusted so that the Dynatrol frequencies indicated that the cell was half-full of liquid. If the interface of the two phases disappeared at the half-full point, the point of interface disappearance was the critical point. By determining the amount of propane in the cell and the cell volume, all critical parameters were determined. The values obtained are shown below.
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    Longitudinal dispersion in the liquid phase of a bubble column chromatograph
    (1967) Rambin, Ronald Emmett; Deans, H. A. (Harry A.)
    The bubble column chromatograph consists of a vertical cylinder sealed at the lower end and partially filled with liquid. Gas is introduced at the bottom in such a way that long, bullet shaped bubbles rise slowly through the liquid. Previous work has shown that the column diameter can be chosen such that the liquid film flowing past the bubble approaches equilibrium with the contents of the bubble. This is the essential requirement of a chromatographic system. This work is a study of the effect of the bubbles on the longitudinal dispersion in the liquid phase. It was found that dispersion increased with increasing bubble length and film thickness for a constant number of bubbles. Thus, it is desirable to use short bubbles when using the bubble column as a chromatographic device.
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    Optimum design in continuous chromatography
    (1970) Briones, Luiz Arthur R; Deans, H. A. (Harry A.)
    This work is a theoretical evaluation of a proposed continuous, plant scale, chromatographic apparatus to perform difficult separations of binary gaseous mixtures. The design of the rotating bed equipment is outlined, after which a specific optimization problem is stated and solved. The optimum column length and angular velocity are defined through two separation factors, longitudinal dispersion coefficient and other design parameters. The first optimization problem is then generalized and solved to yield a performance chart for binary separations, relating feed composition and desired product purity to column length and angular velocity.
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    The single-well chemical tracer test in petroleum reservoirs with multicomponent, two-phase flow effects
    (1980) Gadgil, Abhijit Gangadhar; Deans, H. A. (Harry A.); Davis, Sam H., Jr.; McIntire, Larry V.
    The single-well chemical tracer test has been used previously toumeasure residual oil saturation in oil reservoirs. In this thesis it hasbeen extended to include the effects caused by mobile oil and the leach-ing of mutually soluble components from the oil phase by the injectedbrine.The theory of two-phase flow is combined with the theory of tracermovement in two-phase multicomponent systems. Numerical solutions oftracer tests in an idealized reservoir are used to study the effects ofmobile oil and leaching by detailed simulation. A tracer in mobile oil does follow its theoretical characteristicsaturation, if such a saturation is available. The simulations describedin this thesis are used to predict apparent residual oil saturations thatcompare well with the theoretical characteristic values.When mutually soluble components are present in the oil, their effecton the tracer test results is dependent on the relative frontal veloci-ties of the tracers and the soluble components. If the tracers move intothe formation ahead of the dissolution front, they are relatively unaf-fected by the leaching process. If the tracers are behind the dissolu-tion front, they encounter lower oil saturations. The apparent SOR meas-ured is thus affected by the leaching process.
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    The theory and practice of perturbation chromatography applied to the investigation of H2 and CO chemisorption on a Co-Mo-A1 catalyst
    (1971) Cooper, Charles David; Deans, H. A. (Harry A.)
    The technique of perturbation chromatography using radioactive tracers has been successfully applied to chemisorption studies. Using a flow system with on-line mixing of the pure components, carrier gases of various constant compositions of CO and He, H2, and He, and CO, H2, and He were passed over a Co-Mo-Al catalyst. The steady state system was perturbed by a small sample of either C140 or tritium. The retention time of the pulse was related by chromatographic theory to the adsorption equilibrium function of CO or H2 respectively. Chemisorption isotherms were determined for CO in the 23 to 75°C range and for H2 in the 280 to 450°C range. The total pressure was slightly greater than atmospheric. Heats of adsorption were determined to be approximately 6.5 kcal/mole of CO and 18.2 kcal/mole for H2. It is proposed that the H2 adsorption is activated and follows a Langmuir dissociative mechanism. It is also proposed that the CO adsorption obeys a Freundlich relation, but at very low coverages shifts to a Langmuir two-site mechanism with apparent dissociation of the Co molecule. Some suggestions are made on the possible structure of the catalyst.
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    The use of horizontal bubble columns in gas-liquid chromatography
    (1967) Claypool, David Donald; Deans, H. A. (Harry A.)
    When a single long gas bubble flows with the surrounding liquid through a small capillary tube, its velocity exceeds the average velocity of the liquid. The phenomenon is due to the thin film of stagnant liquid surrounding the bubble. A succession of these bubbles closely spaced, greatly reduces the average liquid velocity even further by making the stagnant film an even greater fraction of the total liquid volume. With relatively long bubbles, very closely spaced together, a great deal of relative separation is possible between the gas and liquid phases at high velocity and therefore, such a system is worthy of consideration as a chromatographic device. The power of resolution attainable by a particular chromatographic system is a ratio of the separation distance between two components, or in this case, the gas and liquid phases, to the half width of the dispersed liquid peak. It is used as a final criteria in evaluating the column performance as bubble velocity, liquid fillet length, and bubble length vary. Behavior of the liquid film thickness, the relative separation, and the liquid phase dispersion coefficient were compared with hydrodynamic and dispersion theories in evaluating the behavior of the resolution. Liquid film thickness increased nearly according to theory at low velocities, but approached limiting values at high velocities. This upper limit of film thickness increased with decreasing fillet length. Increased bubble length appeared to decrease the film thickness only slightly. The net result was a large increase in relative separation with increased bubble length to fillet length, but a limited increase as bubble velocity approached high values. The overall dispersion coefficient increased with nearly the velocity squared, but decreased somewhat with increasing fillet length. The resulting power of resolution appeared to have maxima when plotted against velocity. The value of these maxima increased with an increase in bubble length to fillet length. Further investigations of this system were well justified.