Fugacity Coefficient using Gamma-Phi Formulation of VLE Calculator

Fugacity Coefficient Formula:

\[ \phi = \frac{x_L \times \gamma \times P_{sat}}{y_G \times P_T} \]

Mole Fraction in Liquid Phase (x_L):

Activity Coefficient (γ):

Saturated Pressure (P_sat):

Mole Fraction in Vapor Phase (y_G):

Total Pressure (P_T):

Fugacity Coefficient (φ):

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1. What is Fugacity Coefficient in VLE?

Definition: The fugacity coefficient (φ) is a measure of how much a real gas deviates from ideal gas behavior in vapor-liquid equilibrium (VLE) systems.

Purpose: It's crucial for accurate phase equilibrium calculations in chemical engineering and thermodynamics.

2. How Does the Gamma-Phi Formulation Work?

The calculator uses the formula:

\[ \phi = \frac{x_L \times \gamma \times P_{sat}}{y_G \times P_T} \]

Where:

\( \phi \) — Fugacity coefficient (dimensionless)
\( x_L \) — Mole fraction in liquid phase
\( \gamma \) — Activity coefficient
\( P_{sat} \) — Saturated pressure (Pa)
\( y_G \) — Mole fraction in vapor phase
\( P_T \) — Total system pressure (Pa)

Explanation: This formulation combines liquid-phase activity coefficients (γ) with vapor-phase fugacity coefficients (φ) to model non-ideal behavior.

3. Importance of Fugacity Coefficient

Details: Accurate φ values are essential for designing distillation columns, predicting phase behavior, and modeling chemical processes.

4. Using the Calculator

Tips: Enter all required parameters. Mole fractions should be between 0 and 1. Pressures must be in consistent units (Pa in this case).

5. Frequently Asked Questions (FAQ)

Q1: When is the fugacity coefficient equal to 1?
A: For ideal gases, φ = 1. Real gases at low pressures also approach this value.

Q2: What does a fugacity coefficient less than 1 indicate?
A: Values < 1 suggest attractive intermolecular forces dominate, while > 1 indicates repulsive forces dominate.

Q3: How does temperature affect φ?
A: φ generally approaches 1 as temperature increases, as gas behavior becomes more ideal.

Q4: What's a typical range for activity coefficient (γ)?
A: γ can range from 0 to ∞, but typically between 0.1 and 10 for most systems.

Q5: Can this calculator handle multicomponent systems?
A: This version calculates φ for one component at a time. Multicomponent systems require additional calculations.