Modeling the Thermodynamics of Fluids Treated by CO2 Capture Processes with Peng-Robinson + Residual Helmholtz Energy-Based Mixing Rules

It is currently acknowledged that thermodynamic models routinely used to model the behavior of fluids involved in CO2 capture and storage processes are not sufficiently accurate. Such a deficiency is one of the main sources of uncertainty for estimating the costs associated with these technologies and, as a direct consequence, engineers largely oversize the equipment. In order to reduce the uncertainty related to the calculation of thermodynamic properties, this work aims at providing the optimal parameters of the model Peng-Robinson + equation of state (EoS)/aresE,γ-Wilson mixing rules that are currently able to accurately correlate the phase behavior of systems encountered in CCS technologies. In particular, this model is optimized in this work over the experimental vapor-liquid equilibria (VLE) data of 23 binary systems, resulting from the binary combination of CO2, H2, N2, O2, Ar, CO, CH4, H2S, and H2O, for which data have been found in the literature. The paper shows that this equation of state is reliably applicable to calculate VLE properties of these binary mixtures and suggests the application of this model to represent the thermodynamics of multicomponent fluids treated by CO2 capture processes. Another outcome of this work is the conceptual framework outlined to enable the optimization of thermodynamic models based on the Maximum Likelihood Method, accounting for the correlation and joint uncertainty of model parameters. (Figure Presented).