I&EC REPORTS & COMMENTS Abstracts for the Applied Thermodynamics Symposium
Applied Thermodynamics
The fourth summer symposium, sponsored by the I&EC Division will be held in Washington, D. C. from 12 to 14 June. The chairman, Dr. K. C. Chao of Oklahoma State University, has arranged for two sessions on each of the three days. A11 sessions will be held in the auditorium of the Carnegie Institution near 4 C S Headquarters. Abstracts for the individual papers are given below. Registration information will be found on facing page.
The Chairman
gas-liquid, and gas-solid systems by a perturbation technique. The most advantageous studies have been made under or near steady-state conditions where point equilibrium conditions are essentially satisfied. Under these circumstances it is possible to obtain both thermodynamic and transport information from the characteristic peak velocities and peak shapes, respectively. LIuch of the information by the perturbation technique has not been previously obtainable, by any other means, with the same rapidity, accuracy, and convenience. The application of sas chromatography to study physicochemical behavior is reviewed in various t)-pes of studies. Comments are made on the possible future implications of the variety and types of information that might be obtained by perturbation techniques in future endeavors.
Kwang-Chu Chao received his B.S.Ch.E. degree from the National Chekiang University, and the hl.S. and Ph.D. degrees from the Cniversity of TZ'isconsin. He \vas formerly a research engineer with the Chevron Research Corp., and on the staff of the Illinois Institute of Technology. PVT Measurements on Petroleum At present, Dr. Chao is Associate Reservoir Fluids and Their Uses. Professor of Chemical Engineering J. H. Jacoby and L. Yarborough, Pan at Oklahoma State University, StillAmerican Petroleum Corp., Tulsa, Okla. water, Okla. Thermodynamic Excess Properties of Binary Liquid Mixtures-The Role of Empiricism. H. C. Van Ness, Rensselaer Polytechnic Institute, Troy, N. Y. Experimental methods for the measurement of quantities, \\ hich provide thermodynamic excess functions either directly or by exact thermodynamic relations, have in recent years been developed to the point where they provide data of high accuracy, both routinely and rapidly. I n addition, analytical procedures for the treatment of experimental results have been devised to yield the maximum of useful information for a given investment of time, effort, and money. Both of these areas will be reviewed. T h e uses of such results, both practical and theoretical, will be discussed.
Physico-Chemical Measurements by Gas Chromatography. R. Kobayashi and H. A. Deans, Rice University, Houston, Tex. Gas chromatography has provided the impetus for the study of physicochemical behavior in gas,
The advancement of petroleum reservoir technology imposes a demand for more fluid properties data than ever before, and for data of greater accuracy. Some equipment used for PVT measurements on multicomponent petroleum reservoir fluids is described, and various types of measurements are outlined and illustrated with tvpical data. The uses of such data are discussed from both practical and theoretical viewpoints.
Molecular Theories of Liquids and Mixtures. J. S. Rowlinson, Imperial College, London. There are five principal tasks before those \\.orking on the molecular theories of fluids: (1) to determine the forces between like and unlike molecules; ( 2 ) to show that this kno\vledge is consistent \\-ith the phase changes in a system of one component, and \vith the behavior of fluids a t the critical point; (3) given the information in (2), to explain qualitatively the great variety of phase changes in fluid mixtures, particularly a t hiqh pressures, (4) to calculate quantitatively the thermodynamic properties of gases and liquids, ( 5 ) to calculate quantitatively the properties of
fluid mixtures. I n this review it is shown that there have been some recent advances in (1) and that these have been accompanied by considerable advances in (4). I t is now possible to calculate quantitatively the thermodynamic properties of most single fluids. The third task has not been tackled with the vigor of the other ti\-o but it is shown that there is little to prevent progress here. T h e most difficult tasks are (2) and ( 5 ) and it is shown that the difficulties of both can be reduced to a statement of our ignorance of multibody molecular distribution functions in fluids. Possible future progress is discussed.
Molecular Thermodynamics of Chemical Reactions. c. A. Eckert, University of Illinois, Champaign-Urbana. The technique of molecular thermodynamics coupled with the absolute rate theory provides a promising new approach to some important problems in chemical kinetics. The transition state model reduces the rate process to a much more tractable equilibrium problem, amenable to some of the recently developed theories of solutions. Then, accurate predictions may be made for the effect of pressure and solvent on the rate of a chemical reaction, solely on the basis of thermodynamic data. The classic example is the Bronsted-Bjerrum treatment of reactions between ions. Other cases investipted more recently include the effects of pressure and inert diluents on gas phase reactions, solvent effects on reactions of both polar and nonpolar molecules in the liquid phase, and solvent effects on certain heterogeneous reactions. I n many cases, it is possible to design an optimum solvent mixture for given reactions or sets of reactions.
Applications of Statistical Mechanics: Configurational Properties of Fluids and Fluid Mixtures. J. P. O'Connell, University of Florida, Gainesville, Fla., and J. M. Prausnitz, University of California, Berkeley. IVhile classical thermodynamics has become a common tool, statistical thermodynamics has received only slight attention from chemical engineers. However, applications of statistical thermodynamics are becoming increasingly relevant to the solution of chemical engineering problems. This article summarizes some of those applications which are concerned with configurational equilibrium properties of fluids. First, critical attention is given to the calculation and utility of virial coefficients. Second, applications of the cell theory of liquids are cited with special reference to simple mixtures, hydrocarbons, polymer solutions, and hydrates. T h e third section considers formulations of rigid sphere models \vith appropriate modification for molecular attractions. Finally, although only the beginnings have been made, approximations to the direct correlation function for real fluids noiv appear to give promise for calculating configurational properties of dense fluids including nonspherical and polar substances.
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Equations of State. J. J. Martin, University of Michigan, Ann Arbor. As normally used, equations of state are applied primarily to gases, less often to liquids, and only occasionally to solids. T h e key to most applications is density. If the same high order of precision is to be obtained a t all densities, a relatively simple, short equation will suffice a t low density, while a long, complicated equation is required a t high density. LVhen combined with an appropriate thermodynamic relation an equation of state can predict isothermal changes in enthalpy, entropy, vapor pressure, latent heat of vaporization, activity coefficients, and vaporliquid equilibria in mixtures. Equations that purport to give high precision have arbitrary constants whose number depends principally upon the density and, in a minor way, on the temperature range. T h e capabilities of several of the better known equations are compared. The need for better equations for certain applications is considered. I t appears that several times as many arbitrary constants \vi11 be needed in a good, high precision equation of state, as are used in the most popular working equations of the day. This means that high speed computers will be needed in the bulk of the calculations employing equations of state.
Thermodynamic Properties of Cryogenic Fluids: Survey of Existing Data. F. M. Wilson, P-V-T, Inc., Houston, Tex., and R. G . Clark and F. Hyman, Air Products & Chemicals, Inc., Allentown, Pa. Reliable and efficient cryogenic processing equipment depends to a large extent upon the availability of dependable thermodynamic and thermophysical properties data on the fluid being processed. T o establish \That properties data are available, and which properties require further measurement, a survey has been made of existing experimental and correlated data on thirteen cryogenic fluids. The results of this survey permit one readily to determine the status of phi-sical properties data as they relate to a particular material. For those using such data, the survey provides a ready reference to both the experimental data and correlated data. I t is apparent from the survey that data are lacking in a number of areas and should be measured experimentally to supplement existing data.
scribe various experimental methods, review the available data, discuss commonly used methods of prediction, and compare the methods of prediction in the light of the most recent experimental results. Experimental procedures for the direct determination of enthalpy differences include constant volume calorimetry and flow calorimetry. These procedures are discussed with primary emphasis on flow calorimetry. A review of recent experimental enthalpy data is presented v i t h emphasis on data for mixtures. Various procedures which have been suggested for correlating and predicting the enthalpy relations of fluids and their mixtures include the use of PVT and spectroscopic data, application of various equations of state, and correlations of enthalpy departures and partial molal quantities. The accuracy of these methods is compared on the basis of accurate data from the literature.
Correlating and Predicting Thermodynamic Data-Using Reference Substances. D. F. Othmer and H. T. Chen, Polytechnic Institute of Brooklyn. Design and operation of chemical and related processes and equipment may require knowledge of any physical or chemical property related to thermal or other energy for almost any compound or mixture. Lacking experimental data, chemi-
There is increasing appreciation for the value of accurate enthalpy data a t elevated pressures and reduced temperatures both for pure fluids and mixtures. Experimental data of this type are important but limited in extent especially for mixtures and, therefore, methods of prediction play an important role in estimating enthalpy data. The purpose of this contribution is to de12
Group Contributions in Solutions. C. H. Deal and E. L. Derr, Shell Development Co., Emeryville, Calif, The excess partial molal free energies in mixtures of simple organic molecules at moderate temperatures and pressures (or simply, the activity coefficients) are of everyday importance in applied thermodynamic problems. Consequently, direct predictive correlations, based on contributions associated with the structural groupings in the solute molecule and solvent environment are extremely useful. I n addition, they are intuitively satisfying and contribute to our understanding of mixing effects generally. In spite of the complications which make predictions from first principles such a difficult problem, some surprisingly accurate and far reaching correlations of this kind can be made.
Preregistration Form Symposium on Applied Thermodynamics 4 C S Division of Industrial and Engineering Chemistry LVashington, D. C., June 12-14, 1967
Name
Address
Business or Professional Affiliation
I&EC Division Member
Enthalpies of Fluids at Elevated Pressures and Low Temperatures. V. F. Yesavage, A. E. Mather, D. L. Katz, and J. E. Powers, University of Michigan, Ann Arbor.
cal engineers must estimate or predict probable values. A powerful tool-also for correlating experimental data-is the comparison of the variance of a property of one substance with that of a standard or reference substance under an identical condition, since properties of different substances vary with conditions due to the same mechanisms and defined by the same physical equations. Standard thermodynamic equations are used, including force constants, compressibilities, reduced conditions, etc. The linear functions resulting are simple for graphical, algebraic, or computer use. The interaction, in general, of different physical properties is sho\vn.
0 $16
ACS Member, Nonmember of I&EC Division Student Other
0 $28
0$5.00 0527
Luncheon on 13 June
$7.50
Make check payable to INDUSTRIAL A N D ENOINEERINC CHEMISTRY and send with completed form to the Editor, INDUSTRIAL ASD ESCINEERINC CHEMISTRY, 1155 Sixteenth St., N.W., Washington, D. C. 20036.
INDUSTRIAL A N D ENGINEERING CHEMISTRY
T h e general response surface representing partial molal free energies as a function of group constitution is, in fact, not only relatively simple in many of its areas, but also is quite linear with respect to some of the variables. T h e present paper \vi11 survey some of the recent progress which has been made along these lines-particularly that by the group a t Shell Development Co.--with a view toward defining where, to what degree, and in what way mixtures can be treated in terms of group contributions.
Thermodynamic Aspects of Capillarity. J. C. Melrose, Mobil Oil Corp., Dallas, Tex. T h e thermodynamic treatment of surface regions is systematically developed according to the methods of Gibbs. T h e advantages which result from this approach are sho\vn to include both those of rigor and those of augmented physical insight. A consistent extension of the phase rule to include the degrees of freedom associated with the presence of surface regions is also achieved. For fluid interfaces the role of surface curvature as a thermodynamic variable is examined. I t is shown that in the case of such interfaces, hydrostatic principles supplement the thermodynamic analysis. It is also shown that evidence for the thickness of a fluid interface can be obtained from intensive thermodynamic properties characteristic of the interface and its contiguous bulk phases. These considerations provide a suitable basis for extending the Gibbsian approach to the treatment of line regions-Le., regions ivhich are homoyeneous in one dimension only. T h e status of several classical problems in capillarity is surveyed. Hysteresis effects are considered in the light of a stability condition related to fluid interface configuration. Applications to adsorption phenomena and to capillarity pressure versus saturation relationships in porous solids are outlined.
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The Thermodynamics of Alloys. J. B. Darby, Argonne National Laboratory, Argonne, Ill. T h e thermodynamic properties of binary metallic systems \vi11 be reviewed with particular attention to alloys of the transition metals. Although the quantity of data is more limited, the survey will include the thermodynamic results for intra-rare earth and actinide alloys, a n evaluation of the experimental techniques currently employed in metallurgical thermochemistry will be made, and the experimental limitations will be emphasized. T h e free energy is the desired quantity to describe the equilibrium state in the application of chemical thermodynamics. However, the free energy function is of limited value for systematic consideration of phase stability. T h e heat and entropy of reaction are of more fundamental significance in attempting to relate thermodynamic properties with other properties of the alloys. T h e physical, magnetic, and electronic properties of the various alloy systems will be correlated with the heat and entropy of reaction data. xvhen available.
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