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General Rate Equation of Mass Transfer Calculator

General Rate Equation Formula:

\[ r''''_A = \frac{1}{\left(\frac{1}{k_{Ag} \cdot a} + \frac{H_A}{k_{Al} \cdot a \cdot E} + \frac{H_A}{k \cdot f_l \cdot C_{Bl}}\right)} \cdot p_A \]

m/s
1/m
mol/(m³·Pa)
m/s
mol/(m³·s)
mol/m³
Pa

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1. What is the General Rate Equation of Mass Transfer?

Definition: This equation calculates the overall rate of mass transfer in gas-liquid systems considering resistances in both phases and chemical reaction.

Purpose: It helps chemical engineers design and analyze gas-liquid contactors like absorbers, strippers, and reactors.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ r''''_A = \frac{1}{\left(\frac{1}{k_{Ag} \cdot a} + \frac{H_A}{k_{Al} \cdot a \cdot E} + \frac{H_A}{k \cdot f_l \cdot C_{Bl}}\right)} \cdot p_A \]

Where:

Explanation: The equation combines resistances from gas film, liquid film, and chemical reaction to determine the overall mass transfer rate.

3. Importance of Mass Transfer Rate Calculation

Details: Accurate rate calculation is crucial for designing efficient contactors, optimizing reaction conditions, and predicting system performance.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Default values are provided for reference. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the physical meaning of the enhancement factor (E)?
A: The enhancement factor accounts for how chemical reaction increases the mass transfer rate beyond pure physical absorption.

Q2: How do I determine the interfacial area (a)?
A: This depends on the contactor type and can be estimated from equipment specifications or correlations.

Q3: When can I neglect the reaction term in the denominator?
A: When the reaction is very fast compared to mass transfer (k → ∞), the reaction term becomes negligible.

Q4: What's a typical range for Henry's law constant?
A: HA varies widely (10-5 to 103 mol/(m³·Pa)) depending on the gas and solvent.

Q5: How does temperature affect the calculation?
A: Temperature affects kAg, kAl, HA, and k. Use values appropriate for your operating temperature.

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