Gas Phase Mass Transfer Coefficient Given Humidity Calculator

Formula Used:

\[ k_y = \frac{G}{Z} \times \ln\left(\frac{Y_i - Y_1}{Y_i - Y_2}\right) \]

Mass Velocity of Air (G):

kg/m²s

Height (Z):

Absolute Humidity at Final Temperature (Y_i):

kg/kg

Humidity of Air at Entry (Y₁):

kg/kg

Humidity of Air at Exit (Y₂):

kg/kg

Gas Phase Mass Transfer Coefficient (k_y):

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1. What is Gas Phase Mass Transfer Coefficient?

The Gas Phase Mass Transfer Coefficient (k_y) is a diffusion rate constant that relates the mass transfer rate, mass transfer area, and concentration change as driving force in gas phase systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ k_y = \frac{G}{Z} \times \ln\left(\frac{Y_i - Y_1}{Y_i - Y_2}\right) \]

Where:

\( k_y \) — Gas phase mass transfer coefficient (mol/s·m²)
\( G \) — Mass velocity of air (kg/m²s)
\( Z \) — Height of the tower (m)
\( Y_i \) — Absolute humidity at final temperature (kg/kg)
\( Y_1 \) — Humidity of air at entry (kg/kg)
\( Y_2 \) — Humidity of air at exit (kg/kg)

Explanation: The formula calculates the mass transfer coefficient based on humidity differences across a mass transfer system.

3. Importance of Mass Transfer Coefficient Calculation

Details: Accurate mass transfer coefficient calculation is crucial for designing and optimizing mass transfer equipment such as absorption towers, distillation columns, and humidification systems.

4. Using the Calculator

Tips: Enter mass velocity in kg/m²s, height in meters, and all humidity values in kg/kg. Ensure all values are positive and humidity differences are valid for logarithmic calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of mass transfer coefficient?
A: The mass transfer coefficient quantifies the rate of mass transfer per unit area and concentration difference, essential for equipment design and process optimization.

Q2: What are typical units for mass transfer coefficient?
A: Common units include mol/s·m², m/s, or kg/s·m², depending on the concentration units used.

Q3: When is this formula applicable?
A: This formula is particularly useful for gas-liquid mass transfer systems where humidity differences drive the mass transfer process.

Q4: Are there limitations to this equation?
A: The equation assumes constant mass transfer coefficient and ideal gas behavior. It may need modification for complex systems or non-ideal conditions.

Q5: How does temperature affect mass transfer coefficient?
A: Temperature affects diffusion coefficients and fluid properties, which in turn influence the mass transfer coefficient value.