bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regenaration of fluidized cracking catalysts
Authors: Pansing William F. 
Published: June 2004

AbstractAn equation for correlating regeneration process variables in fluid‐catalytic cracking has been developed from pilot plant data. This equation takes into account not only the chemical‐reaction rate for burning coke deposited on the catalyst but also the diffusional resistance to oxygen transfer. The resistance presumably occurs between the bubbles within the fluidized bed and the void spaces in the relatively denser mass of particles. The coefficient of mass transfer was found to be inversely proportional to the 1.5 power of the average particle diameter and directly proportional to the square of the gas mass velocity. The specific reaction‐verlocity constant was found to be a function to temperature and catalyst activity as well as the nature of the feed from which the coke was deposited. Comparison of pilot plant data with commercial data suggests that nonuniform gas distribution in larger beds makes some of the catalyst ineffective.
Performance of an internally baffled multistage extraction column
Authors: Scheibel Edward G. 
Published: June 2004

AbstractInternally agitated extraction columns generally require increasing heights for a theoretical state for the larger column diameters. The present work describes a design developed to minimize this objection and presents the performance data on a system considered easy to extract and on systems considered difficult to extract. H.E.T.S. values as low as 3 in. on the first system and 4 in. on the second type of system were obtained in an 11½ in I.D. glass column. The stage efficiencies were correlated as a function of power input per unit volume of solvent throughput and the ratio of the flow rate of the dispersed phase to that of the continous phases. The supplementary effect of packing was studied and found to be most beneficial in the system which has a low interfacial tension and is considered easy to extract. By the use of this particular arrangement of internal baffles, it is believed possible, in the larger diameter columns, to reduce the height to a ratio of H.E.T.S. to diameter below the value of ¼ obtained in the present column.
Prediction of specific heat of organic liquids
Authors: Sakiadis Byron C. , Coates Jesse 
Published: June 2004

AbstractA theoretical equation is presented for predicting the specific heat at constant volume and constant pressure of organic liquids as a function of temperature from data on the velocity of sound, infrared and Raman spectra. By use of this equation, the average deviation of the calculated from the experimental values of specific heat for 100 organic liquids at 68°F. is ±1.5%.An alternate correlation for hydrocarbon liquids based on a modified statement of the theory of corresponding states is also presented. Based on it, the average deviation of the calculated from the experimental values for 100 points representing the entire temperature range is ±0.9%.
Chemical reactor stability and sensitivity: II. Effect of parameters on sensitivity of empty tubular reactors
Authors: Bilous Olegh , Amundson Neal R. 
Published: June 2004

AbstractIn this paper extensive calculations on the quasi isothermal tubular reactor are presented. Temperature and concentration profiles were obtained on an analogue computer (R.E.A.C.). The calculations tend to show that there are regions of operation in which the reactor effluent is very sensitive to operating conditions. For example, it is shown that in some regions of operation a small change in the heat transfer coefficient at the reactor wall or a small dilution of the feed will produce large changes in the effluent. In such cases the reactor is said to exhibit parametric sensitivity. It is shown analytically that this sensitivity may be predicted by analyzing the frequency response or transient response of the reactor approximated by a local linearization. This linearization requires complete solutions of the steady state problem. Semiquantitative results are then obtained for the regulation required from a given specification of product limits. The frequency‐response analysis should be useful in connection with the control problem.If the reactor is fed partially with a recycle stream, then experience with electrical systems indicates that the possibility of instability exists. It is shown that at least theoretically these instabilities do exist, and a method based on the transfer function is developed for derivation of criteria of stability or instability.
Flooding characteristics of a pulse extraction column
Authors: Edwards R. B. , Beyer G. H. 
Published: June 2004

AbstractAn investigation using the hexone‐water system was made of flooding in a 1‐in.‐diam. ten‐plate pulse column. An analysis of column operation led to the derivation of an equation for predicting conditions of inadequate pulsation and for establishing the amount of liquid recycled under any operating conditions.
Estimation of heat sources in nuclear reactors
Authors: Alexander Lloyd G. 
Published: June 2004

AbstractKnowledge of local heating rates is needed for estimation of operating temperatures, thermal stresses, and cooling requirements in nuclear reactor components. Heat is liberated by the dissipation of the energy of fission fragments, beta particles, fast neutrons, and gamma photons. Heating rates are formulated in terms of either neutron or gamma flux densities, the corresponding collision probabilities, and appropriate energy transfer coefficients, the forms of which are given. Special methods of estimating the flux densities are discussed. The data on the magnitudes of the various energy sources are reviewed.
Neutron lifetimes and void coefficients for research reactors
Authors: Pigford Thomas H. , Troost Marius , Powell James R. , Benedict Manson 
Published: June 2004

AbstractPrompt neutron lifetimes and viod coefficients were calculated for research reactors using M.T.R.‐type fuel elements, moderators of light and heavy water, and reflectors of light water, heavy water, graphite, and beryllium. Heavy‐water‐reflected and ‐moderated research reactors may have neutron lifetimes of the order of 0.001 sec. as compared with about 0.00006 sec. for a light‐water‐reflected and ‐moderated research reactor. Lifetime of the light‐water core can be improved considerably by use of better reflectors, but at a substantial reduction and even reversal in sign of the void coefficient.
Plate efficiency with chemical reaction—absorption of Carbon dioxide in Monoethanolamine solutions
Authors: Kohl Arthur L. 
Published: June 2004

AbstractThe effect of chemical reaction on plate efficiency has been given little attention in the determination of bubble‐plate efficiencies, although it is of importance in many operations. A typical example is the absorption of carbon dioxide in monoetnanolamine solutions.The over‐all Murphree gas‐phase plate efficiency can be shown to be a function of Kg(A/V) where A/V is the interfacial surface area formed per tray per unit volume of gas. In order to evaluate variations in tray efficiency due to factors influencing Kg, data available in the literature for the absorption of carbon dioxide in monoethanolamine were considered. These showed that the liquid film was controlling and that for a packed column at constant liquid rate the absorption coefficient could be satisfactorily expressed by an equation that resembles somewhat equations which have been developed for the effect of rapid secondorder reactions on kL. However, the observed effect of carbon dioxide partial pressure in the gas is not so great as the theoretical equations would predict.By use of the equation mentioned above to predict Kg, satisfactory correlation of observed plate efficiencies is obtained for a commercial column over a considerable range of conditions. It appears that the correlation can be extended to other pressures, flow rates, and column designs by an evaluation of the effect of these variables on A/V and Kg.
Diffusion coefficients in hydrocarbon systems: n‐heptane in the gas phase of the ethane–n‐heptane and propane–n‐heptane systems
Authors: Carmichael L. T. , Sage B. H. 
Published: June 2004

AbstractBecause little information is available concerning the behavior of hydrocabons under conditions far from equilibrium, it appears desirable to obtain data for the diffusion coefficients of the lighter hydrocarbons in the gas phase.The Maxwell diffusion coefficients of n‐heptane in the gas phase of the ethane‐n‐heptane and propane‐n‐heptane systems were measured at temperatures from 100° to 220° F. and for pressures up to 60 lb./sq. in. The fick diffusion coefficient was calculated as a function of state from these measurements.The experimental results indicate that the interfacial resistance between the liquid and the gas phases into which the transport was taking place is small. It was found that pressure exerted a significant influence upon the Maxwell diffusion coefficient for both of the binary systems investigated. There is a marked decrease in the Maxwell diffusion coefficient with an increase in molecular weight of the stagnant component.
Viscosity of liquids
Authors: Albright Lyle F. , Lohrenz John 
Published: June 2004

AbstractThree viscosity correlations were tested for liquids at their boiling points. Compounds studied included normal paraffins, branched‐chain hydrocarbons, aromatics, halogenated methanes and ethanes, water, and aliphatic alcohols. The correlations were tested for the most part with viscosity and thermodynamic data found in the literature. Some experimental viscosity measurements were made, however, for normal paraffins from pentane to octane at temperatures up to about 300°F., which is higher than has previously been reported.Two correlations are based on Eyring's theory of absolute reaction rates. The third is based on the compressibility factor of the saturated liquid, and this correlation is unique, as all available data for normal paraffins with eight or more carbon atoms are represented by a single curve. The three correlations presented here can be used to extrapolate viscosity data over large temperature ranges up to the critical temperature. Logical predictions of the viscosities of related compounds are possible.
Structure and performance of filter media. II. Performance of filter media in liquid service
Authors: Grace H. P. 
Published: June 2004

AbstractThe performance of nine typical filter media of previously determined pore structure has been determined by the filtration of very dilute suspensious containing spherical particles of known size distribution. The mechanisms of filtration prior to the formation of a macroscopic cake are considered, and the applicability of various filtration laws proposed by Hermans and Bredée to describe these regious of filtration are examined. Regions of “standard‐blocking” filtration are found to occur with each of the filter media examined. The clogging values for the various media over the region of standard blocking are shown to be related quantitatively to the modal value of interfiber pore radius of the media, as measured by the mercury‐intrusion method.
Formation of gas bubbles at horizontal orifices
Authors: Davidson Leon , Amick Erwin H. 
Published: June 2004

AbstractAir bubbles were formed in water and in mineral oil by use of single, circular, horizontal, square‐edged orifices facing upward. Twenty orifices were tested, ranging from 0.017 to 0.79 cm. (0.0067 to 0.31 in.) in radius. Incieasms the whime, of the gas chamber below the orifice (over the range of 4 to 4,000 cc.) was found to increase the bubble size. The gas‐chamber volume was minimized in most of the work in order to confine attention to the effects of orifice size and gas‐flow rate. The liquid containers were large enough to eliminate significant wall effects, and operations were conducted at atmospheric pressure.The gas‐flow rate was varised from about 0.01 to about 250 cc./sec. over the course of the work. At relatively low rates, the orifices generally formed single “static” bubbles, the volumes of which were proportional to the surface tension and orifice radius and independent of the gas‐flow rate. At high flow rates the bubble frequency became high and the bubble volume became proportional to the gas‐flow rate and independent of the surface tension. The bubble frequency reached a maximum value for each orifice, this value being a function of the orifice radius. For air bubbles in water, the correlation of the maximum bubble frequency, nm bubbles/sec., with the orifice radius, r cm., and the air‐flow rate, q cc./sec., was found to be nm = 9.1q0.13/r0.43. The maximum frequencies ranged from about 25 bubbles/sec. for the largest orifices to about 75 bubbles/sec. for the smallest orifices used.It was found that consecutive bubbles paired or coalesced in definite ways in certain ranges of the gas‐flow rate. A description is given of this bubble behavior, based on stroboscopic and photographic observation.
Enthalpy of hydrocarbon mixtures
Authors: Canjar Lawrence N. , Peterka Vernon J. 
Published: June 2004

AbstractA method of estimating enthalpies of mixtures of light hydrocarbons is presented. Enthalpes so obtained are consistent with equilibrium‐vaporization constants that have been correlated with the composition characterization factor, the molal average boiling point (M.A.B.P.).Values of the isothermal‐pressure corrections to the enthalpy of ideal gas mixtures (H°  H) are presented on three plots with parameters of temperature, pressure, and molal‐average boiling point. Pressures range from zero to 1,500 lb./sq. in. abs., temperatures from −200° to 500°F., and M.A.B.P. from −200° to 150°F.
Theorem of corresponding states applied to saturated liquids and vapors
Authors: Hobson Merk , Weber James H. 
Published: June 2004

AbstractThe existence of a single generalized compressibility‐factor relationship for univariant systems has long been denied because reduced variables do not provide a generalized vapor‐pressure relationship. The present study demonstrates that a saturation curve depends on the ability of the theorem of corresponding states to correlate the reduced temperature as a function of reduced, pressure and the critical compressibility factor. Saturation curves for both the liquid and the vapor phases are established from compressibility data on a variety of systems, substantiating this conclusion.The compressibility factors of saturated mixtures are correlated with pseudoreduced properties based upon Kay's pseudocritical concept. The results indicate that the compressibility factors of saturated liquid mixtures can be predicted with reasonable precision over the entire two‐phase region. For pseudoreduced isotherms of unity and above, the same isotherms apply to both phases and are approximately consistent with published compressibility charts for pure gases.
Turbulent exchange of mass and momentum with a boundary
Authors: Hanratty Thomas J. 
Published: June 2004

AbstractVisual observations by Fage and Townend of the behavior of a turbulent‐flow strean near a boundary and experimental data by Lin, Moulton, and Putnam of concentratiol profiles near a boundary contradict the commonly held concept of the “laminar sublayer.” A model developed by Higbie and Danckwerts which is consistent with the visual obser vations of Page and Townend is used to describe the exchange of mass and heat between a turbulent fluid and a solid surface. It is postulated that masses of fluid are contiuously moving to and from the wall. The exchange process then depends on the average contact time of these fluid masses with the wall.The agreement of the concentration profile predicted on the basis of the proposed model with experimental mass transfer data where the exchange process is rate controlling lends support to the usefulness of the model. No equivalent data are available for velocity profiles. Velocity data represent a condition where the transport process within the fluid is playing an important role; however, in the immediate vicinity of the wall the proposed model might serve as a rough approximation of the profile. Such an approximation is made in this paper, and the agreement obtained is much better than should be expected.
Turbulent diffusion in particulately fluidized beds of particles
Authors: Hanratty Thomas J. , Latinen George , Wilhelm Richard H. 
Published: June 2004

AbstractMeasuring the spreading of a tracer dye from a point source yields information on diffusion in glass‐sphere beds fluidized in water. Particulately fluidized beds, which are here formed, are well described by the statistical turbulence equations of Taylor. Mixing parameters—eddy diffusivity, scale, and intensity of turbulence—are established. Transition of these variables is traced from fixed beds through fluidized beds in different degrees of bed expansion.Mixing characteristics of these “ideal” types of fluidization may provide a frame of reference for consideration of more complex systems.
Differential heats of condensation and enthalpies of saturated liquid hydrocarbon mixtures
Authors: Stiehl J. G. , Hobson Merk , Weber James H. 
Published: June 2004

AbstractBy use of saturated‐vapor enthalpies determined by accepted procedures in conjunction with differential latent heats of condensation, the saturated‐liquid enthalpies are established for the system methane–ethane at 200, 400, and 600 lb./sq. in. abs. and for the system ethane–n‐butane and propane–n‐butane at the two lower pressures. Where comparison is possible, the liquid‐enthalpy values obtained by this method are in general agreement with those previously determined by Edmister and Canjar. The procedure used is thermodynamically rigorous and may be applied to any binary mixture, provided the Benedict‐Rubin‐Webb equation of state is valid in the vapor phase and P‐V‐T‐x data are available.
Mass transfer studies in an agitated vessel
Authors: Johnson A. I. , Huang Chen‐Jung 
Published: June 2004

AbstractA study of rates of dissolution of organic solid from a flat surface into turbulent liquid in a mixing tank of 6 in. I.D. is reported for five systems—benzoic acid–n‐water, salicylic acid–water, salicylic acid–benzene, succinic acid–n‐butanol, and succinic acid–acetone. Previous theories for the rates of mass transfer are reviewed and compared, and experimental results analyzed and correlated by an equation in terms of dimensionless groups similar to that of Hixson and Baum, Sherwood and Gilliland, and Rushton and Oldshue. The close agreement between the theoretical and experimental values of the exponent of the Schmidt number in this equation may provide new and significant evidence for the applicability of the surface‐renewal theory to mass transfer from a flat solid surface into a turbulent liquid.For free rotational agitation, a local mass transfer coefficient with respect to the position of a cast solid was detected quantitatively. However, the insertion of four baffles into the tank gave a uniform mass transfer coefficient regardless of the position of the cast solid. A decrease in the mass transfer coefficient was observed when baffles were used.The advantages of the constant and stationary interface, the stability and simplicity of the apparatus, the possibility of duplicating experimental results, and the success of the detection of a local mass transfer coefficient suggest that the present apparatus and procedures could be used for the study of the theory of mass transfer rates from flat surfaces.
The chemical equilibrium of the Ammonia synthesis reaction at high temperatures and extreme pressures
Authors: Winchester Leonard J. , Dodge Barnett F. 
Published: June 2004

AbstractChemical equilibrium in this reaction has been determined experimentally by a static or nonflow method at temperatures of 400° and 450°C. and at pressures of 1,000 to 3,500 atm. Equilibrium was approached from both sides and the two reacting gases were always in the stoichiometric ratio. The results are presented both as mole percentage of ammonia in the equilibrium mixture and as the equilibrium constant Kp. The constant, Kp, which is a function of pressure, was calculated from Kp°, its value at p = 0, by five different methods and from them the corresponding mole percentages of ammonia were derived for comparison with the experimental results. All such calculations involve assumptions of varying degrees of validity, and no calculated value can be considered accurate. However two of the calculation methods give values which agree reasonably well with the experimental values.
Critical constants of the naphthenic hydrocarbons
Authors: Thodos George 
Published: June 2004

AbstractGroup‐contribution values are presented and, together with those already developed for the aliphatic hydrocarbons (10, 11), make possible the evaluation of both van der Waals' constants for the naphthenic hydrocarbons. These constants can be used to produce the critical temperatures, pressures, and volumes of these compounds entirely from a knowledge of their chemical structure.Critical constants have been calculated for several naphthenes, and from a comparison of them with the constants resulting from the methods of Riedel (5, 6) and Lydersen (3) it was found that the critical constants calculated by these three methods were in fair agreement for naphthenes having short alkyl side chains and progressively deviated from each other as the chains were permitted to lengthen. An appraisal has been made on five naphthenes along the lines proposed by Sondak and Thodos (9) in order to see whether these calculated critical constants properly represent the vapor‐pressure function resulting from vapor‐pressure data found in the literature for these hydrocarbons.Critical constants have been produced for more than fifty naphthenes, for which vapor‐pressure data are available in the literature, and will be used in a separate, comprehensive vapor‐pressure study for hydrocarbons of this type.
Thermodynamic properties of n‐hexane
Authors: Weber James H. 
Published: June 2004

AbstractThermodynamic properties of n‐hexane have been calculated over a temperature range of 32° to 540°F. and up to a pressure of 600 lb./sq. in. abs. These properties were determined from vapor pressure, volumetric, heat capacity, and latent heat of vaporization data through the application of rigorous thermodynamic relationships. The calculated data have been found to be internally consistent. The enthalpy values are believed to be accurate to within 0.5 B.t.u./lb. and the entropy values to 0.0005 B.t.u./(lb.)(°R.).