Studies of methods used in phase equilibrium calculations /
Two general topics are covered in this dissertation: (1) new
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1995.
|
| Subjects: | |
| Online Access: | Link to OAKTrust copy http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=742746191&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Two general topics are covered in this dissertation: (1) new procedures for phase equilibrium calculations and (2) specific application of the new procedures to the C02/H20 system A robust and fast algorithm has been developed to calculate phase equilibria based upon a new Gibbs energy minimization method, the Equal Area Rule (EAR) method, for multicomponent and/or multi-phase mixture systems. Eubank and Hall (1995) have shown the equal area rule (EAR) applies to the composition derivative of the Gibbs energy of a binary system at fixed pressure and temperature regardless of derivative continuity. In this dissertation, we show that EAR can be extended up to quaternary systems (any by analogy to any number of components). In ternary systems, a single directional vector is sought in composition space; at equilibria this vector is the familiar tie-line. A sensitive criteria for equilibrium under EAR is equality of orthogonal derivatives such as 9 r =- (aglaxi),2,P,Tat the end points (cc and 0), where g =- (AmG/RT). Repeated use of the binary algorithm published in the above reference allows rapid, simple solutions for ternary problems. Using a similar scheme, the EAR method was extended to quaternary system Examples of applications covering up to three-phase mixture cases are given. Another new criterion, termed the maximum partial equal area rule (WEAR), searches for the directional vector as presented in this dissertation. We define an area (AOC) related to the overall composition as the partial area inside the upper area (U) or lower area (L) on the g, - xi diagrani. This area is always a maximum when equilibrium is achieved in agreement with a thermodynamic proof presented here within. In addition, a study is presented about the prediction of the phase equilibrium behavior of the carbon dioxide/water system. The model used in this work is the Peng Robinson equation of state with the Wong-Sandler mixture combining rules (MCR). The parameters used in the Wong- Sandler MCR have been selected to minimize the deviations between experimental data and prediction results for liquid- phase solubilities. The model has been applied to pressures up to 1000 bar, and temperatures up to 623 K Three-phase pressures and compositions are also calculated using the EAR procedure employed with this model. |
|---|---|
| Item Description: | Vita. "Major Subject: Chemical Engineering". |
| Physical Description: | xv, 148 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |