1. What is Mass Transfer Coefficient by Film Theory?

Definition: This calculator determines the convective mass transfer coefficient based on the film theory of mass transfer.

Purpose: It helps chemical engineers and researchers estimate the mass transfer rate between phases in processes like absorption, distillation, and extraction.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( k_L \) — Convective mass transfer coefficient (m/s)
• \( D_{AB} \) — Diffusion coefficient (m²/s)
• \( \delta \) — Film thickness (m)

Explanation: The mass transfer coefficient is directly proportional to the diffusion coefficient and inversely proportional to the film thickness.

3. Importance of Mass Transfer Coefficient

Details: The mass transfer coefficient is crucial for designing separation processes, predicting reaction rates, and optimizing industrial equipment.

4. Using the Calculator

Tips: Enter the diffusion coefficient (D_AB) in m²/s and film thickness (δ) in meters. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is typical range for diffusion coefficients?
A: For gases: 10⁻⁵ to 10⁻⁴ m²/s; for liquids: 10⁻⁹ to 10⁻¹⁰ m²/s.

Q2: How is film thickness determined?
A: Film thickness depends on flow conditions and can be estimated from boundary layer theory or experimental correlations.

Q3: What are limitations of film theory?
A: Film theory assumes a stagnant film and constant concentration gradient, which may not hold in turbulent flow.

Q4: How does temperature affect the calculation?
A: Temperature strongly affects D_AB (increases with temperature) but has less effect on δ.

Q5: Can this be used for gas-phase mass transfer?
A: Yes, but gas-phase coefficients are typically much larger than liquid-phase ones.