Predicting the Physicochemical Properties of Molecules in Petroleum Based on Structural Increments

Abstract

The structure-oriented lumping (SOL) method has been widely applied to molecular-level modeling and optimization in the refining industry. Calculating the physicochemical properties of products obtained by the SOL models can effectively guide the evaluation of product quality and optimization of the process. In this study, the SOL method was improved by extending the structural increments from 22 to 38 to describe the molecules in petroleum more accurately. According to the basic law that the properties and structures of molecules are inseparable, the structural increments with similar physical meanings were combined into a functional group to reduce the dimension to 11 characteristic parameters to describe the molecular structure, and a property prediction method that can be combined with the molecularlevel refining models based on the optimized SOL method was constructed. In addition, the accuracy of the selection and definition of the 11 functional groups was verified by analyzing and discussing the effects of functional groups on the properties, which, in turn, ensured the accuracy of the property prediction models. Compared with other property prediction methods, this method can be combined with the SOL method to provide reliable predictions of the boiling point, critical temperature, critical volume, critical pressure, density, cetane number, motor octane number, and research octane number of molecules.

Structure-Oriented Lumping Method: An Effective Tool for Molecular Refining

“…It can be seen that the SOL method is a method for characterizing petroleum molecules that can overcome the shortcomings of other methods, improve the applicability and practicality of the model, and provide more accurate and comprehensive data support for the simulation and optimization of petroleum processing processes. This method has the following advantages: (1) wide applicability, as it can be combined with other methods for easy subsequent model calculation; (2) high flexibility, as different structural increments can be selected to describe the core structure and side chain structure of molecules; (3) clear structure, as a molecular library with a clear structure can be constructed using a two-dimensional homologous distribution; and (4) high computational efficiency, because it can reduce the number of optimization variables and improve optimization speed.…”

Molecular Level Simulation of the Conversion and Distribution of Sulfides in the Fluid Catalytic Cracking and Hydrotreating Processes to Improve the Cleanliness of Gasoline and Diesel

“…In 1992, Jaffe et al of ExxonMobil put forward the concept of structure-oriented lumping (SOL) method, which developed the lumping reaction kinetic models from fraction level to molecular level. , Zhu et al and Tian et al established a vacuum gas oil catalytic cracking kinetic model and a delayed coking model using the SOL method, respectively. , Yu et al built a molecular-level reaction kinetic model of hydro-upgrading process to study the reaction behaviors of polycyclic aromatic hydrocarbon molecules . The molecular-level SOL reaction kinetic models − for oil refining processes have been developed. These models can describe the reaction network in detail according to the reaction mechanism so they can reveal the transformation laws of sulfides at the molecular level in petroleum refining and predict their molecular distribution in gasoline and diesel.…”