H. Kreulen et al., MICROPOROUS HOLLOW-FIBER MEMBRANE MODULES AS GAS-LIQUID CONTACTORS .2. MASS-TRANSFER WITH CHEMICAL-REACTION, Journal of membrane science, 78(3), 1993, pp. 217-238
Absorption determined by mass transfer in the liquid is described well
with the Graetz-Leveque equation adapted from heat transfer. The infl
uence of a chemical reaction on the mass transfer was simulated with a
numerical model and tested on the absorption Of CO2 in a hydroxide so
lution. Absorption determined by mass transfer in the gas phase and th
e pores of the membrane was also analysed experimentally and numerical
ly. It was found that the gas phase concentration profile is establish
ed at a very short distance from the entrance of the fibre. This resul
ts in a constant Sherwood number along the fibre. A module coated with
a very thin silicone rubber layer showed absorption rates comparable
to the uncoated membranes. If absorption liquids are used which wet th
e membranes, resulting in leaky membranes, such a coating can enlarge
the application of microporous hollow fibre membrane module.