(480b) Pseudo-Component Techniques for Prediction of Thermophysical Properties of Hydrocarbon Mixtures and Fuels up to High Temperatures and Pressures

Experimental property measurements for fuels (e.g., gasoline, kerosene, jet, and diesel) at high temperature and high pressure (HTHP) conditions are expensive and time consuming. These limitations can be overcome using an equation of state (EoS) to predict mixture properties beyond the range of experimental observations. Although fuels are complex mixtures of hydrocarbon compounds with properties and composition that vary due to quality specifications, only a few composition-based approaches have been proposed to model their properties. However, these techniques have been limited by the need for experimental measurements to fit the EoS parameters or requiring complex compositional characterization to define multiple pseudo-components.

Here, we present pseudo-component techniques based upon the perturbed-chain statistical associating fluid theory (PC-SAFT) EoS of Gross and Sadowski (IECR, 40, 1244, 2001) to predict thermodynamic and transport properties of hydrocarbon mixtures and fuels up to HTHP conditions. We use group contribution approaches to correlate and calculate the model parameters, treating the mixtures as a single pseudo-component and eliminating the need for binary interaction parameters. Only two to three measured or calculated mixture properties are required as inputs: the number averaged molecular weight, hydrogen to carbon ratio of the mixture, and optionally for transport properties, a single data point at a chosen reference point to fit one of the model parameters. Transport properties (i.e., viscosity and thermal conductivity) are predicted by combining PC-SAFT with the entropy scaling approach of Rosenfeld (Phys. Rev. A, 15, 2545, 1977). Thermophysical properties are predicted for hydrocarbon mixtures and jet and diesel fuels up to 600 K and 3,500 bar with average mean absolute percent deviations of 1, 9, and 2 % for density, viscosity, and thermal conductivity, respectively, compared to experimental data.