Past MSE Consortium Accomplishments

OLI’s Mixed Solvent Electrolyte (MSE) model was developed with partial support of the MSE Consortium Phase I, II and III. At present, OLI Systems is in the final months of Phase III of the MSE model development and parameterization project. During the course of this project, we have achieved the following objectives:

1. A comprehensive MSE thermodynamic model

This thermodynamic model calculates phase equilibria, speciation, caloric properties and density. With this model, OL has obtained unparalleled accuracy in reproducing experimental data for systems containing electrolytes in water, organic or mixed solvents ranging from infinite dilution to the pure solute or fused salt limit. The details of this model can be found in supporting papers, which are available in the OLI Resource Library.

2. Databanks of model parameters

The MSE databanks now contain parameters for more than 1500 species for general-purpose calculations (MSEPUB), supplemented by two specialized databanks for corrosion-related (CRMSE) and geochemical (GEMSE) calculations. These databanks cover the chemistry of widely encountered electrolyte and nonelectrolyte systems as well as specific systems of compelling interest to our industrial sponsors. The actual chemical systems covered by parameters projected through the end of the current MSE III project are shown in the MSE component list.

3. Complex phase combinations including LLE with two electrolyte phases

The OLI Engine has been extensively upgraded to work in the full range of concentrations. It can accurately compute solid-liquid equilibria in systems with multiple competing solid phases, liquid-liquid equilibria with electrolyte speciation in both coexisting phases, solid-gas equilibria and it can deal with substantially extended temperature ranges – well below 0°C and above 300°C, provided that the temperature is roughly below 0.9 of the critical temperature of the mixture.

4. Transport properties: viscosity, electrical conductivity, thermal conductivity, and self-diffusivity

With these models, clients have the capability to simulate these transport properties for aqueous, nonaqueous or mixed-solvent systems in the same range of concentration and temperature that is covered by the thermodynamic model. The details of these models are available in supporting papers available in the OLI Resource Library.

The work on developing a surface tension model is currently in progress.

5. Dual AQ & MSE models in OLI software products

MSE is now available in ESP, OLI Pro, the Analyzers, and OLI Alliance Engines in Aspen Plus, UNISIM, and PRO/II (Aspen HYSYS in 3Q 2009)

6. MSE in stability diagrams

Stability diagrams (i.e., the real solution Pourbaix diagrams, the species-species and yield diagrams) can now be generated using the mixed-solvent model. Thus, thermodynamics of corrosion can be studied using the MSE as well as the aqueous model.

7. Improvements in heat and mass transfer coefficient calculations

More predictive correlations have been developed for heat and mass transfer coefficents. This enables predictive calculations for heat- and mass-transfer limited packed towers. These facilities have been implemented in ESP, UNISIM and OLI Pro. Gas-phase transport properties have also been implemented to support these calculations. Upon completion of the surface tension model, it will be integrated with these correlations and the last missing piece of information will be provided to calculate mass transfer coefficients.

8. Modeling surface phenomena in conjunction with MSE

Computation of ion exchange, molecular adsorption and surface complexation has been enabled in conjunction with the MSE model. Further, a new solid-phase activity coefficient model based on the Wilson equation has been implemented to improve accuracy for multicomponent solutions. to enable predictive calculations for heat- and mass-transfer limited packed towers.