Bubble Column k_La & Holdup (ε)

Calculation Explanation

This calculator estimates the gas holdup (ε) and the volumetric mass transfer coefficient (k_La) for bubble columns operating in the heterogeneous flow regime with coalescent, non-viscous liquids (e.g., water). It uses the following empirical correlations:

Gas Holdup (ε):
ε = 0.6 ⋅ (v_g ⋅ p₀ / p)^0.7
Where:

• ε: Gas holdup (fraction of volume occupied by gas, dimensionless).
• v_g: Superficial gas velocity (m/s).
• p₀: Reference pressure (assumed 1 bar).
• p: Operating pressure at the point of interest (bar).

Volumetric Mass Transfer Coefficient (k_La):
k_La = 0.32 ⋅ (v_g ⋅ p₀ / p)^0.7
Where:

• k_La: Volumetric mass transfer coefficient (s^-1).
• v_g, p₀, p: As defined above.

Assumptions: These correlations are typically valid for:

• Bubble columns.
• Heterogeneous flow regime (usually occurs at higher gas flow rates).
• Coalescent and non-viscous media (like tap water or distilled water).
• Ensure consistent units for p and p₀ (bar is used here).