Molar Flux of Diffusing Component A through Non-Diffusing B based on Mole Fractions of A and LMPP Calculator

Molar Flux Formula:

\[ N_A = \frac{D_{AB} \cdot P_t^2}{\delta} \cdot \frac{y_{A1} - y_{A2}}{P_{B,lm}} \]

Diffusion Coefficient (D_AB):

m²/s

Total Pressure of Gas (P_t):

Film Thickness (δ):

Mole Fraction of A at Point 1 (y_A1):

Mole Fraction of A at Point 2 (y_A2):

Log Mean Partial Pressure of B (P_B,lm):

Molar Flux of Diffusing Component A (N_A):

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1. What is Molar Flux of Diffusing Component A?

Definition: Molar flux (N_A) measures the amount of substance (in moles) that diffuses through a unit area per unit time in a binary gas mixture.

Purpose: This calculator determines the molar flux of component A through non-diffusing component B based on mole fractions and log mean partial pressure.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ N_A = \frac{D_{AB} \cdot P_t^2}{\delta} \cdot \frac{y_{A1} - y_{A2}}{P_{B,lm}} \]

Where:

\( N_A \) — Molar flux of component A (mol/(s·m²))
\( D_{AB} \) — Diffusion coefficient (m²/s)
\( P_t \) — Total gas pressure (Pa)
\( \delta \) — Film thickness (m)
\( y_{A1} \) — Mole fraction of A at point 1
\( y_{A2} \) — Mole fraction of A at point 2
\( P_{B,lm} \) — Log mean partial pressure of B (Pa)

Explanation: The formula accounts for the concentration gradient (via mole fractions), diffusion characteristics, and the logarithmic mean partial pressure of the non-diffusing component.

3. Importance of Molar Flux Calculation

Details: Accurate molar flux calculations are essential for designing separation processes, mass transfer equipment, and understanding diffusion phenomena in chemical engineering.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Mole fractions should be between 0 and 1. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the log mean partial pressure?
A: It's the logarithmic average of the partial pressures of component B at two different points in the system.

Q2: When is this equation applicable?
A: For steady-state diffusion of component A through stagnant (non-diffusing) component B in a binary gas mixture.

Q3: How do I determine the diffusion coefficient?
A: It can be measured experimentally or estimated using theoretical correlations based on gas properties.

Q4: What are typical units for molar flux?
A: The standard SI unit is moles per square meter per second (mol/(s·m²)).

Q5: Can this be used for liquid-phase diffusion?
A: No, this specific form is for gas-phase diffusion. Liquid-phase diffusion uses different formulations.