Average Molecule Construction of Petroleum Fractions Based on ¹H‐NMR

Abstract

The calculation of chemical structures and physical properties is the basis of petroleum refining optimization. In this article, a method to build an average molecule model for hydrocarbons and petroleum fractions is developed. 1 H-NMR, molecular weight, and elemental composition were used as input parameters to construct a single molecular model that represents the average chemical structure. The average molecules were constructed by assembling the average building blocks, which are a set of predefined structural fragments, covering typical hydrocarbon and heteroatom functional groups in petroleum systems. After applying a group contribution method to the derived molecule, the bulk property of a sample could be directly calculated. The method was validated by being applied to various model compounds (including paraffins, cycloalkanes, aromatics, and heteroatom-containing species), where it successfully predicted the average building blocks, unit sheets number, and physical properties. The application of this method to petroleum fractions was demonstrated.

Catalogue of Plausible Molecular Models for the Molecular Dynamics of Asphaltenes and Resins Obtained from Quantitative Molecular Representation

“…These models and modified versions have been used in a number of simulation studies. 73,1974,75,76,77 So called "digital oils", including an in silico production of whole crudes 78,79 , of petroleum fractions 80 , and vacuum residue fractions 81 have also been produced in a similar fashion. A related procedure, labelled "structure-oriented lumping" 82 has been also extended to vacuum residue fractions.…”

“…The Headen models have been employed in extraordinarily long simulations (over 0.5 μs), revealing how aggregation is a “slow” process as compared to the solvent dynamics. These models and modified versions have been used in a number of simulation studies. − So-called “digital oils”, including an in silico production of whole crudes, , of petroleum fractions, and vacuum residue fractions, have also been produced in a similar fashion. A related procedure, labeled “structure-oriented lumping”, has been also extended to vacuum residue fractions …”

Dual‐objective optimization for petroleum molecular reconstruction based on property and composition similarities

“…Petroleum molecular reconstruction refers to the method of obtaining quantitative molecular composition based on available analytical data. In the early years, only bulk properties or average molecular structure data can be obtained, such as average molecular structure obtained by 1 H NMR, average molecular weight obtained by vapor pressure osmometry (VPO), and elemental content obtained by elemental analysis 4–6 . Therefore, only bulk properties could be used for petroleum molecular reconstruction.…”

“…In the early years, only bulk properties or average molecular structure data can be obtained, such as average molecular structure obtained by 1 H NMR, average molecular weight obtained by vapor pressure osmometry (VPO), and elemental content obtained by elemental analysis. [4][5][6] Therefore, only bulk properties could be used for petroleum molecular reconstruction. In the early years, Liguras and Allen introduced the molecular-level "structural model" in the modeling of the catalytic cracking process, using molecular composition instead of lumped composition.…”