Document Type

Thesis

Date of Award

9-30-1985

Degree Name

Master of Science in Chemical Engineering - (M.S.)

Department

Chemical Engineering, Chemistry and Environmental Science

First Advisor

Edward Charles Roche, Jr.

Second Advisor

Irwin Hundert

Third Advisor

John E. McCormick

Abstract

The CHESS (Chemical Engineering Emulation System) is a generalized steady-state, sequential-modular chemical process simulation program. In this thesis, the thermophysical data prediction capability of CHESS has been expanded by: incorporating more accurate thermodynamic phase-behavior models, by utilizing these models in generating a wider range of thermophysical properties, and providing an updated and expanded database for pure-component physical properties.

The overall performance of the simulation system's thermophysical package has been evaluated using the study of a subprocess consisting of various rotational equipment modules.

In this work, the Chao-Seader liquid phase activity coefficient model has been reinstalled in conjunction with the original Redlich-Kwong equation of state for the vapor phase. As an alternative, the Soave-Redlich-Kwong equation of state has also been used as a vapor phase model with the Chao-Seader activity coefficient model to generate vapor-liquid equilibrium constants and other properties. The Peng-Robinson equation of state has also been included as an option to predict vapor and liquid phase behavior.

The data-library approach of the original version of CHESS has been reinstated. The library has also been updated to provide a expanded database of pure component properties. The overall property prediction procedure has been expanded to provide: liquid and vapor enthalpy departure functions, liquid and vapor entropy departure functions, vapor phase specific heat departure functions and liquid densities.

The limited results of the subprocess simulation indicate that no single model(s) can be used to represent all the thermophysical properties under the conditions normally encountered in natural gas processing, that is high pressure and low temperature. The Peng-Robinson model has been found to be more accurate in the prediction of most of the properties, such as equilibrium constants, specific heat departures and vapor entropy departures. However, the Redlich-Kwong/ Chao-Seader and the Soave-Redlich-Kwong/ Chao-Seader combinations have predicted enthalpy departures more accurately.

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