Extended UNIQUAC (Universal QuasiChemical) is a thermodynamic (activity coefficient) model, specially designed for electrolyte solutions (both aqueous solutions and mixed solvents).
The vapor phase is described by the SRK equation of state. The model has been developed by Kaj Thomsen and Peter Rasmussen and it has been found widespread applicability. Both the model description and applications of the model can be found in an extensive material prepared by Kaj Thomsen which can be downloaded here
In CERE, Extended UNIQUAC can be used in many forms and for various applications as mentioned below:
- SPECS: For diverse calculations (activity coefficients, solid-liquid equilibria, thermal properties and binary, ternary and quaternary phase diagrams…) using the Extended UNIQUAC model. All calculations in SPECS are for aqueous electrolyte solutions.
A separate Electrolyte database is provided in SPECS.
- SCALE-CERE: For determining the risk of scale formation (precipitation of salts) as a function of temperature, pressure and composition of formation water/brine.
- CAPCO2: This module can be used in any process simulator, through CAPE-OPEN interface, to simulate the rate based column (absorber/desorber) for CO2 capture unit with aqueous ammonia or alkanolamines.
- Aspen Plus® User Model: The Extended UNIQUAC thermodynamic property package is developed in the form of user model to be used in Aspen Plus.
In addition to extended UNIQUAC, CERE has developed an extensive electrolyte database with over 150.000 experimental data collected from almost 3000 scientific papers.
Finally, CERE offers an on-line course on Electrolyte Solution Thermodynamics.
Software Availability
SPECS and SCALE-CERE can be downloaded from the members section for the CERE member companies.
Member companies can also order data free of charge from the electrolyte database.