Computer aided molecular design for undefined petroleum fractions

• Published in: Fluid phase equilibria 2015-03, Vol.390, p.14-22
• Main Authors: Valdez-Patrinos, José M., Vázquez-Román, Richart, Morán-Corona, Erika, Inchaurregui-Méndez, José A., Quiroz-Pérez, Efraín
• Format: Article
• Language: English
• Subjects: CAMD; Carbon; Computational fluid dynamics; Computer aided design; Crude oil; Cubic equations of state; Mathematical analysis; Mathematical models; Molecular weight; Petroleum fraction; Phase equilibria; Pseudocomponents
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2015.01.017

[Display omitted] •A CAMD strategy is used to characterize petroleum fractions for simulation purposes.•MINLP models are developed for CAMD and solved with GAMS.•A cubic equation of state is used in the phase equilibria calculation and its parameters are estimated with group-contribution based methods.•Experimental data are fitted to characterize petroleum fractions using a reduced number of components. Undefined petroleum fractions typically composed of several components are characterized through a reduced set of components representing the whole mixture. The selected set should appropriately reproduce experimental phase equilibria behavior such as TBP curves as well as mass contents of elementary species such as amounts of carbon and hydrogen. Three approaches have been developed in this work. In the first approach, a predefined number of components are selected from a given database and a numerical evaluation selects the characterizing components by fitting experimental and calculated properties. A synthesis of a predefined number of components is carried out in the second approach using a mathematical programming model for the computer aided molecular design (CAMD). In the third approach, parameters such as critical properties and molecular weight are freely estimated so that characterizing components are not necessarily identifiable or physically existing components; i.e., hypothetical components would be used to characterize petroleum fractions. The Peng–Robinson equation, a typical cubic equation of state, is used to describe the complex phase behavior in the three proposed approaches. The numerical evidence indicates that undefined petroleum fractions can be highly represented in phase equilibria calculations by a properly selected set of components.