A modified electrolyte non‐random two‐liquid model with analytical expression for excess enthalpy: Application to theMEA‐H₂O‐CO₂system

Abstract

Accurate thermodynamic properties of electrolyte systems are critical for the design and operation of many chemical processes. A comprehensive description of the thermodynamic framework for multielectrolyte mixed solvent systems is presented, where the parameter structure of the symmetric electrolyte‐non‐random two liquid (e‐NRTL) model is reformulated and a thermodynamically consistent and analytically derived formulation for the excess enthalpy is developed from the e‐NRTL model. The refined parameter structure of the e‐NRTL model avoids numerical singularities of the analytical formulation for the excess enthalpy in the absence of ionic species and extends the derived excess enthalpy formulation to non‐electrolyte systems. The thermodynamic framework is demonstrated for the MEA‐H2O‐CO2 case study using experimental data on thermodynamic quantities for the binary MEA‐H2O system and the ternary MEA‐H2O‐CO2 system. The model is implemented in Pyomo and will be available for release in the Institute for the Design of Advanced Energy Systems (IDAES) computational platform.