A PC‐SAFT model for heavy hydrocarbon thermodynamics in downstream separation processes

Abstract

The Advanced Petroleum Parameterization Scheme (TAPPS) provides a very accurate method to determine pure component petroleum fraction model parameters for the polar PC-SAFT equation of state. In this work we extend the TAPPS/PC-SAFT petroleum thermodynamics methodology to vacuum residuum (VR) ranged molecules. The challenge for these heavy species is twofold: first, the normal boiling point ceases to be a sensible descriptor of molecular size; and second, the phase behavior of interest in downstream processing is liquid-liquid equilibria (LLE). We develop new parameter models for both unary and binary polar PC-SAFT parameters for VR ranged molecules. In addition to PC-SAFT parameters, we also develop a scheme to redefine a detailed model of composition to a number of pseudo-components manageable in a process simulator (10 2) using a lumping scheme based on the fraction of aromatic carbon and molecular weight. We demonstrate that this methodology allows for the accurate description of VR/paraffin LLE.

Modeling of the Deasphalting Process by a Residue–Solvent Equilibrium Calculation Using Continuous Thermodynamics

“…The DAO yield behavior is consistent with that reported in the literature, ,, where the DAO yield drops toward the solvent critical temperature. Additionally, the DAO yield increases as the solvent carbon count increases, implying that the polyaromatics are more soluble in high-molecular-weight solvents. ,, Also, DAO quality increases with temperature (Figures and a,b). For instance, the LHVR has an API gravity of 12.7, and after processing in a single-stage deasphalting unit at elevated temperatures, the DAO quality obtained is significantly better (Figure ).…”

“…The pressure used in the calculations was 35 bar. The DAO yield behavior is consistent with that reported in the literature, 5,38,39 where the DAO yield drops toward the solvent critical temperature. Additionally, the DAO yield increases as the solvent carbon count increases, implying that the polyaromatics are more Industrial soluble in high-molecular-weight solvents.…”

Dry Glass Reference Perturbation Theory Predictions of the Temperature and Pressure Dependent Separations of Complex Liquid Mixtures Using SBAD-1 Glassy Polymer Membranes

“…To apply DGRPT to this complex mixture, we must generate pure component PC-SAFT parameters m , σ , ε , α p for each petroleum species. For this, we used the approach of Marshall et al [ 26 , 27 ] which accurately generates PC-SAFT parameters on the basis of pure component boiling point temperature ( T b ), specific gravity ( SG ), molecular weight ( MW ) and the fraction of carbon which is aromatic ( f a ). The molecular weight and f a are defined in each SOL-lumped species, and specific correlations for T b and SG are from ExxonMobil proprietary models.…”

Heavy Petroleum Supercritical Fluid Deasphalting Process Simulation Based On the Saturate, Aromatic, Resin, and Asphaltene Composition

“…Kontogeorgis et al proposed the cubic-plus-association (CPA) model, which can improve the SAFT model via the simplification of substituting the chain and dispersion terms with the cubic equation of state. The CPA model demonstrated good performance in the prediction of the vapor–liquid equilibrium. − Gross et al developed the perturbed-chain SAFT model by applying the perturbation theory of Barker and Henderson to a hard-chain reference fluid, expanding the application range of the SAFT, and providing the equation parameters of the pure components for the calculation. − Marshall et al constructed the composition model of the heavy oil feedstock using the structure-oriented lumping (SOL) method, employed the PC-SAFT equation of state to calculate the liquid–liquid equilibrium in the solvent deasphalting process. − …”