I need a simple procedure to calculate the mass transfer coefficient of CO2 absorption in an alkaline mixed solution. I have an absorption cell, the CO2 will be bubbled in the solution and measured.
You, my Semitic Brother, do not need any measurements, as CO2 molecula is not hydrated and behaves like a sphera in the solvent with viscosity 1 cP. Take the Einstein formula for diffusion coefficient D, substitute the radius of CO2 molecula, you have the result. You will get D = 10 in power - 5 in CGS units as valid estimate. Any experimental measurements will introduce larger error, than this estimate.
For mass transfer coefficient of gas absorption, you simply measured the amount absorbed over time, then plot cumulative mass absorbed per m2 vs SQRT (time), you can determine the mtc from the gradient with other known parameters. YOu can refer to my paper Gas diffusion into viscous and non-Newtonian liquids ++ Chem Eng Sci, 1992.
https://www.researchgate.net/publication/223798494_Gas_diffusion_into_viscous_and_non-Newtonian_liquids?ev=prf_pub
Article Gas diffusion into viscous and non-Newtonian liquids
Normally, such coefficients are used for designing of absoroption column of CO2 captruing from flue gases (stationary gases) of power plants. using liquid ammonia or any other absrobent liquid. Since this process is most economic.
Thus, for:
1) Diffusion and physical absorption: you only need CO2 henry law
2) Absorption with chemical reaction: you need mass transfer process. I still remember a work done by:
Chatterjee S.G., Altwicker E.R., 2008, Film-Penetration Model for Nonisothermal Physical Gas Absorption, Ind. Eng. Chem. Res., 47, 7368–7374
Danckwerts P.V., Kennedy A.M., Roberts D., 1963, Kinetics of CO2 absorption in alkaline solutions – II – Absorption in a packed column and tests of surface-renewal models, Chemical Engineering Science, 18, 63-72
can help you.
Regards
