Studies of gas absorption: V. Mass transfer in film reactors (wetted wall columns)

Measurements of mass transfer coefficients in film reactors are reported. Turbulence due to entrance effects is shown to explain why mass transfer coefficients in the gas film may be proportional to the 0.8th power of mass velocity even, within the region where streamline flow is normal. It is shown that the velocity profile of gas flow is completely developed only when the apparatus is longer than 25 times the diameter. A theoretical expression for mass transfer in the liquid film is derived. This expression is valid for Reynolds numbers below 25. At higher Reynolds numbers, turbulence in the exterior parts of the layer begins to play a part.