Activity Coefficient for Component 2 for Infinite Dilution using NRTL Equation Calculator

Formula Used:

\[ γ2∞ = \exp\left(\frac{b_{12}}{R \cdot T} + \frac{b_{21}}{R \cdot T} \cdot \exp\left(-\frac{α \cdot b_{21}}{R \cdot T}\right)\right) \]

NRTL Equation Coefficient (b12):

J/mol

NRTL Equation Coefficient (b21):

J/mol

NRTL Equation Coefficient (α):

Temperature for NRTL model:

Activity Coefficient 2 for Infinite Dilution (γ2∞):

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1. What is Activity Coefficient for Infinite Dilution using NRTL Equation?

Definition: This calculator determines the activity coefficient for component 2 at infinite dilution using the NRTL (Non-Random Two-Liquid) equation.

Purpose: It helps chemical engineers and researchers predict non-ideal behavior of liquid mixtures at infinite dilution conditions.

2. How Does the Calculator Work?

The calculator uses the NRTL equation:

\[ γ2∞ = \exp\left(\frac{b_{12}}{R \cdot T} + \frac{b_{21}}{R \cdot T} \cdot \exp\left(-\frac{α \cdot b_{21}}{R \cdot T}\right)\right) \]

Where:

\( γ2∞ \) — Activity coefficient for component 2 at infinite dilution
\( b_{12}, b_{21} \) — NRTL binary interaction parameters (J/mol)
\( α \) — Non-randomness parameter (typically 0.2-0.47)
\( R \) — Universal gas constant (8.314 J/mol·K)
\( T \) — Absolute temperature (K)

3. Importance of Activity Coefficient Calculation

Details: Accurate activity coefficients are essential for phase equilibrium calculations, distillation design, and predicting mixture behavior.

4. Using the Calculator

Tips: Enter the NRTL coefficients (default values provided), non-randomness parameter, and temperature in Kelvin. Temperature must be > 0K.

5. Frequently Asked Questions (FAQ)

Q1: What is infinite dilution condition?
A: It refers to the limit where the concentration of one component approaches zero while the other component is nearly pure.

Q2: Where can I find NRTL parameters?
A: They are typically obtained from experimental data or thermodynamic databases like DECHEMA or NIST.

Q3: What's a typical range for α?
A: The non-randomness parameter usually ranges between 0.2 and 0.47 for most systems.

Q4: How does temperature affect the result?
A: Higher temperatures generally decrease the activity coefficient's deviation from ideality.

Q5: Can this be used for electrolyte solutions?
A: No, the NRTL model in this form is for non-electrolyte systems. Special modifications are needed for electrolytes.