Fuller-Schettler-Giddings For Binary Gas Phase Diffusivity Calculator

Fuller-Schettler-Giddings Equation:

\[ D_{AB} = \frac{1.0133 \times 10^{-7} \times T^{1.75}}{P_T \times \left( (\Sigma v_A^{1/3} + \Sigma v_B^{1/3})^2 \right)} \times \sqrt{\frac{1}{M_A} + \frac{1}{M_B}} \]

Temperature of Gas:

Total Pressure of Gas:

Bar

Total Atomic Diffusion Volume A:

m³

Total Atomic Diffusion Volume B:

m³

Molecular Weight A:

kg/mol

Molecular Weight B:

kg/mol

Diffusion Coefficient (DAB):

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1. What is the Fuller-Schettler-Giddings Equation?

The Fuller-Schettler-Giddings equation estimates the binary gas phase diffusion coefficient (DAB) using temperature, total pressure, atomic diffusion volumes, and molecular weights. It provides an accurate method for predicting diffusion coefficients in gas mixtures.

2. How Does the Calculator Work?

The calculator uses the Fuller-Schettler-Giddings equation:

\[ D_{AB} = \frac{1.0133 \times 10^{-7} \times T^{1.75}}{P_T \times \left( (\Sigma v_A^{1/3} + \Sigma v_B^{1/3})^2 \right)} \times \sqrt{\frac{1}{M_A} + \frac{1}{M_B}} \]

Where:

\( D_{AB} \) — Diffusion coefficient (m²/s)
\( T \) — Temperature of gas (K)
\( P_T \) — Total pressure of gas (Bar)
\( \Sigma v_A \) — Total atomic diffusion volume A (m³)
\( \Sigma v_B \) — Total atomic diffusion volume B (m³)
\( M_A \) — Molecular weight A (kg/mol)
\( M_B \) — Molecular weight B (kg/mol)

Explanation: The equation accounts for the temperature dependence, pressure effect, molecular sizes, and molecular weights in predicting gas phase diffusion coefficients.

3. Importance of Diffusion Coefficient Calculation

Details: Accurate diffusion coefficient estimation is crucial for mass transfer calculations, reactor design, separation processes, and understanding transport phenomena in chemical engineering applications.

4. Using the Calculator

Tips: Enter temperature in Kelvin, pressure in Bar, atomic diffusion volumes in cubic meters, and molecular weights in kg/mol. All values must be positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for atomic diffusion volumes?
A: Atomic diffusion volumes range from approximately 0.014 to 0.02 m³ for common gases, with specific values available in diffusion volume tables.

Q2: How accurate is the Fuller-Schettler-Giddings equation?
A: The equation typically provides accuracy within 5-10% for most gas pairs at moderate temperatures and pressures.

Q3: What are the limitations of this equation?
A: The equation may be less accurate for polar molecules, at very high pressures, or for molecules with complex structures.

Q4: Can this equation be used for liquid phase diffusion?
A: No, this equation is specifically designed for gas phase diffusion. Different equations are used for liquid phase diffusion coefficients.

Q5: How does temperature affect diffusion coefficients?
A: Diffusion coefficients increase with temperature, typically following a T^1.75 relationship as shown in the equation.