🚀 PyThermoModels v1.6.0 Release Notes

🧪 New Feature: UNIFAC Example

Added a comprehensive example for the UNIFAC activity model in examples/activity-models/activity-unifac-1.py. This script demonstrates:

# Load UNIFAC parameters
group_parameters_dict, group_interaction_dict = load_unifac_data()
activity_unifac.load_data(
	group_data=group_parameters_dict,
	interaction_data=group_interaction_dict
)

# Assign component group structures
components_group_data = {
	"acetone": {"CH3": 1.0, "CH3CO": 1.0},
	"n_heptane": {"CH3": 2.0, "CH2": 3.0}
}
activity_unifac.set_component_groups(component_groups=components_group_data)

# Calculate activity coefficients
model_inputs = {
	"mole_fraction": {"acetone": 0.047, "n_heptane": 0.953},
	"temperature": [307, "K"]
}
res_, other_values = activity_unifac.cal(model_inputs=model_inputs)
print(res_)

# Compute excess Gibbs free energy
gibbs_energy = activity.general_excess_molar_gibbs_free_energy(
	mole_fraction=model_inputs["mole_fraction"],
	activity_coefficients=res_["value"]
)
print(f"general excess gibbs free energy: {gibbs_energy}")

🛠️ Improvements

Enhanced modularity and usability. Example:

# Modular activity model configuration
activity = ptm.activity(
    components=["acetone", "n_heptane"],
    model_name="UNIFAC"
)
print(activity)

Improved data loading and assignment:

# group_parameters_dict, group_interaction_dict already constructed from external sources such as:
# The Properties of Gases and Liquids, Sixth Edition
# Vapor-Liquid Equilibria Using Unifac: A Group-Contribution Method By Aage Fredenslund

activity_unifac.load_data(
    group_data=group_parameters_dict,
    interaction_data=group_interaction_dict
)

Structure of UNIFAC Data:

group_parameters_dict (from UNIFAC Data CSV):

CSV format:

main-group,sub-group,group-id,volume,surface-area
m,k,-,R[k],Q[k]
1,1,CH3,0.9011,0.848
1,2,CH2,0.6744,0.54
# ...

Python dict example:

{
    "CH3": {
        "main_group": 1,
        "sub_group": 1,
        "group_id": "CH3",
        "volume": 0.9011,
        "surface_area": 0.848
        },
    "CH2": {
        "main_group": 1,
        "sub_group": 2,
        "group_id": "CH2",
        "volume": 0.6744,
        "surface_area": 0.54
        },
    # ...
}

group_interaction_dict (from unifac_with_na.csv):

CSV format (excerpt):

"[m,n]",1,2,3,...
1,0,86.02,61.13,...
2,-35.36,0,38.81,...
# ...

Python dict example:

{
	"1": {'': 1.0, '1': 0.0, '2': 86.02, ...}
	# ...
}

These structures allow the UNIFAC model to compute activity coefficients based on group contributions and their interactions.

📚 Documentation

Updated docs and examples for activity models. Example:

# Step-by-step comments in example
# 1. Load parameters
# 2. Assign groups
# 3. Calculate coefficients
# 4. Compute Gibbs energy

🐞 Bug Fixes

Minor fixes in activity model initialization and data assignment. Example:

# Fixed: Proper initialization and assignment
activity = ptm.activity(components=["acetone", "n_heptane"], model_name="UNIFAC")
activity_unifac = activity.unifac
activity_unifac.set_component_groups(component_groups=components_group_data)

💡 How to Use

See the new UNIFAC example to learn how to:

# 1. Load and set UNIFAC parameters with respect to the valid structure
# group_parameters_dict, group_interaction_dict 

# 2. Assign component group data
activity_unifac.set_component_groups(component_groups=components_group_data)

# 3. Calculate activity coefficients and excess Gibbs energy
res_, other_values = activity_unifac.cal(model_inputs=model_inputs)
gibbs_energy = activity.general_excess_molar_gibbs_free_energy(
	mole_fraction=model_inputs["mole_fraction"],
	activity_coefficients=res_["value"]
)

---

Thank you for using PyThermoModels! For more details, check the README and docs.

# 🚀 PyThermoModels v1.5.0

This update introduces comprehensive example scripts for thermodynamic modeling, focusing on activity coefficient calculations and equation of state (EOS) fugacity computations.

🆕 New Examples in the Examples Folder

📚 Activity Models (examples/activity-models/)

We've added extensive examples for activity coefficient models, including NRTL and UNIQUAC, with various approaches for parameter handling and calculations.

Key Scripts

• Basic Activity Calculations: activity-1.py, activity-2.py, activity-3.py and variants (activity-1-2.py, etc.) - Demonstrate activity coefficient calculations for binary mixtures like ethanol-butyl-methyl-ether using NRTL model.
• Parameter Calculation: calc-parameters-nrtl.py, calc-parameters-uniquac.py - Show how to fit model parameters to experimental data.
• Inline and Build Model Sources: Scripts like calc activity using nrtl inline source-1.py, calc activity using uniquac inline source and build model source-1.py - Illustrate different ways to provide model parameters and equations.

Example: Activity Coefficient Calculation with NRTL

import pyThermoModels as ptm
import pyThermoDB as ptdb

# Load thermodb data
thermodb = ptdb.load_thermodb('thermodb_nrtl_ethanol_butyl-methyl-ether.pkl')

# Initialize activity model
activity = ptm.activity(components=['ethanol', 'butyl-methyl-ether'], model_name='NRTL')

# Model input
model_input = {
    "mole_fraction": {'ethanol': 0.4, 'butyl-methyl-ether': 0.6},
    "tau_ij": [[0.0, 1.21670526], [0.65831047, 0.0]],
    "alpha_ij": {'ethanol | ethanol': 0.0, 'ethanol | butyl-methyl-ether': 0.680715, 'butyl-methyl-ether | ethanol': 0.680715, 'butyl-methyl-ether | butyl-methyl-ether': 0.0}
}

# Calculate activity coefficients
res, others = activity.nrtl.cal(model_input=model_input)
activity_coefficients = others['AcCo_i_comp']
print(f"Activity coefficients: {activity_coefficients}")

🧪 Equation of State Models (examples/eos-models/)

New examples showcase fugacity calculations for pure components and mixtures using Peng-Robinson (PR) and Redlich-Kwong (RK) equations of state.

EOS Key Scripts

• Pure Component Fugacity: fugacity-gas.py, fugacity-liquid.py - Calculate fugacity for single components in vapor and liquid phases.
• Mixture Fugacity: fugacity-mixture.py - Demonstrate fugacity calculations for multi-component mixtures.
• Build Model Sources: Variants like fugacity-gas using build model source.py - Show how to use pre-built model sources for EOS calculations.

Example: Fugacity Calculation for Pure Component (Gas Phase)

import pyThermoModels as ptm

# Initialize EOS
eos = ptm.eos()

# Model input for propane
model_input = {
    "component": "propane",
    "temperature": [300.1, 'K'],
    "pressure": [9.99, 'bar']
}

# Calculate fugacity using PR EOS
res = eos.cal_fugacity(model_name='PR', model_input=model_input, model_source=model_source)
print(f"Fugacity: {res}")

Example: Fugacity Calculation for Mixture

# For a CO2-n-butane mixture
model_input = {
    "feed-specification": {'CO2': 0.15, 'n-butane': 0.85},
    "pressure": [10, 'bar'],
    "temperature": [444, 'K']
}

# Calculate mixture fugacity using RK EOS
res = eos.cal_fugacity_mixture(model_name='RK', model_input=model_input, model_source=model_source)
print(f"Mixture fugacities: {res}")

🔧 Key Features Demonstrated

• ThermoDB Integration: All examples show how to load and use thermodynamic databases for component properties.
• Multiple Model Approaches: Examples cover inline parameter specification, build model sources, and parameter fitting.
• Phase Equilibria: Calculations for vapor-liquid equilibria using activity models and EOS.
• Parameter Estimation: Scripts for calculating interaction parameters from experimental data.

📖 How to Use

1. Navigate to the examples/ folder
2. Choose the relevant subfolder (activity-models/ or eos-models/)
3. Run the Python scripts to see calculations in action
4. Modify input parameters to fit your specific systems

🎯 What's Changed

• Added 20+ new example scripts across activity and EOS modeling
• Enhanced documentation through practical code examples
• Improved integration with pyThermoDB for data handling