## Calculation of critical points of multicomponent mixtures using the BWRS equation

 dc.contributor.advisor Heidemann, Robert A. dc.contributor.author Dahouk, Mohammed A. (Mohammed Ahmed), 1956- dc.date.accessioned 2005-07-21T20:22:58Z dc.date.available 2005-07-21T20:22:58Z dc.date.issued 1982 dc.description Bibliography: p. 76-82. en dc.description.abstract A computational procedure has been developed for solving two nonlinear equations that characterize the critical state for multi­component mixtures described by the Benedict-Webb-Rubin-Starling (BWRS) equation of state. The two equations are obtained by setting to zero the quadratic and the cubic forms in the Taylor series expansion of the Helmholtz free energy as a function of the mole numbers. The procedure treats finding a zero of the quadratic form (which defines the stability limit) as an eigenvalue problem where temperature is the eigenvalue at a given volume. The cubic form is treated then as a function of volume alone and its zeros are found by the secant method. A computer program has been developed and used for calculating vapour-liquid and liquid-liquid critical points for multicomponent systems. A proposal was developed for providing initial guesses for volume and temperature which permitted convergence to a vapour-liquid critical point in all cases. The proposed algorithm has been used to perform critical point computations on mixtures with up to 20 components. It is capable of converging to a vapour-liquid critical point (if one exists) for all the systems studied in three to six iterations. High density, liquid­liquid critical points have also been calculated by making an appropri­ate initial volume guess. It was found that the BWRS equation can have many stable and unstable points satisfying the critical criteria for a given mixture. Even for pure components, a second unstable critical point can be calculated. en dc.format.extent xiii, 82 leaves : ill. ; 30 cm. en dc.identifier.citation Dahouk, M. A. (1982). Calculation of critical points of multicomponent mixtures using the BWRS equation (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/17781 en_US dc.identifier.doi http://dx.doi.org/10.11575/PRISM/17781 dc.identifier.lcc QC 307 D33 1982 en dc.identifier.other NL Number: 63182 en dc.identifier.uri http://hdl.handle.net/1880/22695 dc.language.iso eng dc.publisher.institution University of Calgary en dc.publisher.place Calgary en dc.rights University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. dc.subject.lcc QC 307 D33 1982 en dc.subject.lcsh Critical point dc.title Calculation of critical points of multicomponent mixtures using the BWRS equation dc.type master thesis thesis.degree.discipline Chemical and Petroleum Engineering thesis.degree.grantor University of Calgary thesis.degree.name Master of Science (MSc) ucalgary.item.requestcopy TRUE ucalgary.thesis.notes UARC en ucalgary.thesis.uarcrelease no en
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