Modeling of Processes with Aqueous Ionic Solutions - Electrolytes and Salts

• Explore ionic chemistry setup with trend analysis for pH, density, viscosity and enthalpy at different temperature, pressure and at different ionic strength
• Review the electrolyte property methods framework and study the property parameters used for modeling ionic simulation
• Learn estimating and regressing physical property parameters for ionic systems
• Model processes such as gas sweetening and pH/neutralization in liquid-liquid equilibrium

• Instruction on basic topics
• Demonstrations of general features
• Instructor-guided exercises
• Hands-on workshops that apply learned concepts
• Example problems
• Detailed course notes

Introduction using the Electrolyte Wizard

·       Use the Electrolyte Wizard to automatically generate ions, salts, reactions, Henry components, and an appropriate electrolyte property method from a small set of apparent components

·       Review and refine the generated chemistry and component list, removing irrelevant species and reactions and adjusting Henry‑component selections as needed.

Workshop #1 : Learn how to use the Electrolyte Wizard

Review Electrolytes

·       Understand how Aspen Plus handles electrolyte systems, including dissociation, non‑ideal interactions, gas solubility, and salt precipitation

·       Recognize the different electrolyte component types—solvents, supercritical species, ions, and salts—and how each must be defined for accurate modeling

·       Address key modeling challenges such as correct chemistry definition, parameter requirements, data needs, and convergence behavior in electrolyte simulations

Electrolyte Chemistry

·       Understand how electrolyte chemistry is defined, edited, and controlled in Aspen Plus using the stoichiometry and equilibrium forms

·       Apply equilibrium conventions and parameters—including activity‑based formulations, asymmetric vs. symmetric reference states, and K‑STOIC / K‑SALT constants—to model dissociation and salt‑precipitation behavior

Workshop #2 : Evaluate a Salt Solubility

Component Approaches

·       Understand the differences between true and apparent component approaches and how each represents electrolyte species in simulations

·       Recognize how the chosen approach affects reporting, flowrates, chemistry visibility, and unit‑operation behavior in Aspen Plus

·       Apply and convert between approaches using property sets and RSTOIC blocks to report or manipulate compositions as needed

Workshop #3 : Use Property Sets for Reports

Workshop #4 : Perform a Component Approach Conversion

Property Sets

·       Understand and use electrolyte‑specific property sets such as pH, pOH, solubility index, and composition‑conversion metrics

·       Apply property sets to analyze electrolyte behavior, including saturation, precipitation tendencies, and true‑vs‑apparent composition reporting

·       Use electrolyte property sets in design‑specs and sensitivity analyses to study system responses such as neutralization curves and species distributions

Workshop #5 : Electrolyte Property Sets

Electrolyte Property Methods

·       Understand the common structure of electrolyte property methods, including how vapor‑ and liquid‑phase fugacities are computed

·       Apply gamma–phi VLE formulations, Henry‑component treatment, and electrolyte‑specific activity‑coefficient models

·       Identify and use the required parameter sets (binary, pair, ion, salt, solvent) for accurate electrolyte thermodynamics across different property methods

Electrolyte Property Parameters

·       Identify the minimum thermodynamic parameters required for ions, salts, and solvents

·       Calculate enthalpy, Gibbs energy, and heat capacity for electrolyte mixtures using solid, gas, and ion‑specific models such as Barin, CPAQ0, and Criss‑Cobble

·       Apply and regress electrolyte density models, especially the Clarke model, to represent solution volumes accurately

·       Demo/Workshop: Data Regression Example

Workshop #6 : Density Regression Example

Sources of Property Data

·       Identify and obtain required physical‑property data for electrolyte simulations from databanks, inserts, literature, experiments, estimation, or regression.

·       Use Aspen Properties databanks and electrolyte insert files to supply pure‑component, binary‑interaction, and chemistry parameters.

·       Select appropriate data sources and parameter types (pure‑component, binary, electrolyte pair, or equilibrium constants) to ensure accurate electrolyte modeling.

Electrolyte Property Regression

·       Regress electrolyte property and activity‑coefficient parameters using experimental data across VLE, LLE, SLE, and solubility measurements.

·       Select and apply appropriate regression targets (e.g., GMELCC, K‑SALT, pure‑component parameters) based on the data type and chemistry.

·       Evaluate and refine electrolyte solubility and precipitation behavior through regression and validation against experimental datasets.

Workshop #7 : Regress Electrolyte Pair Parameters

Workshop #8 : Evaluate Na₂SO₄ solubility and precipitation

Manipulators for Electrolyte Simulation

·       Understand how ChargeBal enforces electroneutrality in electrolyte recycle loops

·       Use MakeUp to maintain stable flow and composition in circulating electrolyte systems

·       Apply both manipulators to keep charge balance and steady‑state operation in CO₂‑capture simulations

Workshop #9 : CO₂ Capture with Mixed Amine Solvent

Distillation Columns with Electrolytes

·       Understand how electrolytes behave in distillation columns and why RadFrac’s electrolyte capabilities matter

·       Apply chemistry, kinetics, and precipitation handling in RadFrac and rate‑based distillation models

·       Simulate electrolytic distillation using both equilibrium and rate‑based approaches, including strategies to improve convergence

Workshop #10 : Electrolytic distillation

Liquid-Liquid Equilibrium

·       Understand how to model liquid–liquid equilibrium in electrolyte systems using consistent chemistry and activity‑coefficient models

·       Identify and adjust key parameters—binary interactions, pair parameters, and electrolyte vapor‑pressure inputs—to ensure accurate phase‑splitting predictions

·       Simulate vapor–liquid–liquid equilibrium for mixed aqueous/organic systems using ENRTL‑RK or ELECNRTL

Workshop #11 : VLL equilibrium of a sour-water/organic system

Ice Formation

·       Configure electrolyte chemistry to include ice formation as a precipitation reaction

·       Use the generated ICE solid component and K‑SALT reaction to model freezing behavior in salt–water systems

Workshop #12 : Ice Formation for a NaCl-Water solution

Estimation

·       Estimate pure component physical property parameters for electrolyte systems

Workshop #13 : Parameter Estimation

Electrolyzer Models in Aspen Plus

·       Learn how to setup an Alkaline

·       Electrolyzer

·       Distinguish between various run modes

Workshop #14 : Alkaline Electrolyzer

Hydrogen Ortho-Para Conversion

·       Discuss how electrolyte chemistry data can be generated and implemented into Aspen Plus

Workshop #15 : Explore H₂ ortho-para thermodynamic model

Appendix A

• ·       Composition Conversion