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Definition: The Gamma-phi formulation is a method for calculating vapor-liquid equilibrium (VLE) that accounts for non-ideal behavior in both phases.
Purpose: This calculator determines the liquid phase mole fraction using the Gamma-phi approach, which is essential for distillation design and phase equilibrium calculations.
The calculator uses the formula:
Where:
Explanation: The formula relates vapor and liquid phase compositions through thermodynamic properties and system conditions.
Details: This approach is crucial for accurate phase equilibrium calculations in chemical processes, especially when dealing with non-ideal mixtures.
Tips:
Q1: When is the Gamma-phi approach necessary?
A: For systems where both vapor and liquid phases show significant non-ideal behavior, unlike Raoult's Law which assumes ideal behavior.
Q2: How do I determine the fugacity coefficient?
A: Use equations of state (like Peng-Robinson) or experimental data. For near-ideal vapors, φ ≈ 1.
Q3: What affects the activity coefficient?
A: Molecular interactions, temperature, and composition. It's typically >1 for positive deviations from Raoult's Law.
Q4: Can xliquid exceed 1?
A: No, if you get values >1, check your inputs - likely incorrect Psat or invalid combination of parameters.
Q5: How does temperature affect the calculation?
A: Temperature primarily affects Psat (through Antoine equation) and may affect γ and φ.