I. Application of Digital Computer Techniques to the Calculation of Thermodynamic Properties of Hydrocarbon Systems. II. Isobaric Heat Capacities of N-Hexane, Methylcyclopentane and N-Octane at the Bubble Point

Citation

Connolly, Thomas Joseph (1950) I. Application of Digital Computer Techniques to the Calculation of Thermodynamic Properties of Hydrocarbon Systems. II. Isobaric Heat Capacities of N-Hexane, Methylcyclopentane and N-Octane at the Bubble Point. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/yapz-fy69. https://resolver.caltech.edu/CaltechTHESIS:07302025-223752277

Abstract

I.

The thermodynamic properties of mixtures of real substances may be calculated rigorously from certain calorimetric or spectroscopic measurements on the components together with volumetric measurements on the mixtures. The practical impossibility of making sufficient volumetric measurements precludes application of such an analysis to all mixtures of interest. One possible solution of this problem is the use of an equation of state which satisfactorily represents the volumetric behavior of mixtures. Benedict, Webb, and Rubin (9,10) met with considerable success in developing such an equation for mixtures of light hydrocarbons. These authors have proposed an equation of state and derived thermodynamic equations which give accurate predictions of properties of both homogeneous and heterogeneous hydrocarbon systems.

These equations are quite complex and their solution a very time-consuming operation when performed by conventional computational techniques. It was proposed that this difficulty could be overcome by use of recently developed high-speed digital computers. Accordingly, an investigation has been made into the feasability of solving the equations of Benedict et al on a punched card digital computer known as the Electronic Calculating Punch, Type 604, manufactured by the International Business Machines Corporation. The results of the investigation are reported in the first part of this thesis. The development and application of digital techniques for the calculation of thermodynamic properties of coexisting phases in light hydrocarbon systems are discussed. A routine procedure for such a calculation which may be completed in about one and one half hours is presented. Results of calculations on the methane-ethylene-ethane system and the methane-propane system are presented in graphical and tabular form. Where possible, comparison is made with experimental measurements.

II

The isobaric heat capacity at bubble point has been determined at temperatures from 80° to 200° F. for n-hexane, methyl-cyclopentane, and n-octane. This quantity was calculated from directly measured values of the isochoric heat capacity in the two-phase region by the use of supplementary volumetric data. The latter were obtained from experimental measurements, when available, or estimated from the law of corresponding states. The results are presented in graphical and tabular form.

Thesis Files