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When to use the MSE thermodynamic framework instead of the AQ thermodynamic framework

Objective:

The Mixed-Solvent Electrolyte Thermodynamic Framework is the default framework. This article explains why it should be used over the older AQ Thermodynamic framework.

The MSE thermodynamic framework offers a more comprehensive approach to handling various chemical interactions, although it still does not completely replace the older AQ framework. This raises a question: "Why might someone still use the older AQ framework?"

Comparison of MSE and AQ Frameworks

MSE Framework Advantages:

  • It doesn't have concentration limits, handling both electrolytes and non-electrolytes smoothly.
  • All data is rigorously evaluated and based on a thorough review and adaptation of existing literature.
  • It excels in predicting behaviors in systems with multiple components that may form solid phases.
  • Version 12 of our software now includes the MSE corrosion model. This significant enhancement allows users to predict corrosion accurately across various process compositions for two corrosion-resistant alloys: Alloy 2507 and Alloy 2205.
  • MSE is specifically tailored for certain applications:
      • Oil and gas chemistry, particularly when substances like glycols and methanol are present.
      • Processes involving sublimation.
      • Chemistry occurring in refinery overhead systems, including interactions with amines and their derivatives.
      • Systems with a high concentration of CO2.
      • The chemistry involving electrolytes in non-water-based solutions and across dual-liquid phases.
      • Mixed-solvent acid-base interactions.
      • Specialized chemical processes in urea and caprolactam production.
  • It provides more accurate predictions in:
      • Power plant chemistry involving borates.
      • Hydrometallurgical processes.
      • The chemistry of corrosion products.
      • Handling of nuclear waste and carbohydrates.

AQ Framework Advantages:

  • It has a larger database of chemical components.
  • It includes some components not yet covered by MSE, such as chelates, certain low-solubility organics, and specific halide salts like bromides and iodides.
  • Its treatment of corrosion kinetics is more extensive, covering a wider range of metallurgies.

Technical Differences:

MSE and AQ handle basic thermodynamic properties like electrical conductivity, viscosity, and self-diffusivity. However, MSE extends its capabilities to thermal conductivity, surface tension, and interfacial tension, which AQ does not cover. Additionally, MSE supports more detailed models for non-aqueous phases and dual-phase systems, which are limitations in the AQ framework.

In summary, while MSE offers a robust, detailed framework suitable for complex and diverse systems, AQ's extensive database and specific component coverage may still render it necessary in scenarios where MSE still needs to provide solutions. This choice ultimately depends on your project or research's specific needs and constraints.

 

Overview of Differences Between MSE and AQ Frameworks

  MSE AQ
Thermodynamic properties    
  • Electrical Conductivity
Yes Yes
  • Viscosity
Yes Yes
  • Self-diffusivity
Yes Yes
  • Thermal Conductivity
Yes No
  • Surface Tension
Yes No
  • Interfacial Tension
Yes No
  • Standard-State Properties
Helgeson-Kirkham-Flowers Helgeson-Kirkham-Flowers
  • Activity model Aqueous phase
No limit on the concentration Ionic strengths less than 30 mol/Kg
  • Activity model non-aqueous phase
Mixed-Solvent Electrolyte Soave-Redlich-Kwong (SRK)
  • Vapor phase activity model
SRK

SRK

 

  • Solid phase
Direct thermodynamic properties (e.g., Gibbs Free Energy) Solubility parameters

 

References:

  • Wang, P., Anderko, A., & Young, R. D. (2002). A speciation-based model for mixed-solvent electrolyte systems. Fluid Phase Equilibria, 203, 141-176.
  • Wang, P., Anderko, A., Springer, R. D., Kosinski, J. J., & Lencka, M. M. (2010). Modeling chemical and phase equilibria in geochemical systems using a speciation-based model. Journal of Geochemical Exploration, 106, 219-225.
  • Wang, P., Anderko, A., & Young, R. D. (2004). Modeling viscosity of concentrated and mixed-solvent electrolyte systems. Fluid Phase Equilibria, 226, 71-82.
  • Anderko, Andrej, Lencka, Malgorzata. "Computation of Electrical Conductivity of Multi component Aqueous Systems in Wide Concentration and Temperature Ranges. Ind. Eng.Chem.Res. 1997, 36, 1932-1943
  • Anderko, A., Wang, P., & Rafal, M. (2002). Electrolyte solutions: from thermodynamic and transport property models to the simulation of industrial processes. Fluid Phase Equilibria, 194-197, 123-142.

 

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