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 tuks_123 July 22, 2010 01:24

Volumetric mass transfer coefficient

My objective is to evaluate overall volumetric mass transfer coefficient, using CFD, for CO2 absorption from Air (gas) to Amine (liquid) with no reactions.

Using basic definition "N*a = K_L*a*(C_L_eq - C_L)". Where N is molar flux, K_L*a is volumetric coefficient and C_L_eq and C_L are concetration at interface (in equlibrium with gas phase conc) and bulk concentration. All values pertaining to CO2 in liquid ammonia/amine.

Can we evaluate K_L*a from hydrodynamics and concentration profiles in CFD?
My approach could be
1. Define diffusivity of CO2 in Air (gas) and amine (liquid).
2. Define gas-liquid interphase mass transfer using a model where only Henry's constant for CO2 needs to be specified.
3. Solve the momentum, mass transfer equations for gas, liquid phases and get concentrations pofiles.
4. Use concentration profiles to calculate molar flux (N) and then calculate K_L*a.
As I dont know details of interphase mass transfer models in CFX. Also I am not sure if approach is correct?
Experts views are welcome.

Thanks
Tuks

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