Abstract
The mass transfer behaviour of a rotating mesh disc contactor was studied by measuring the rate of mass transfer of acetic acid extraction from toluene solution by water. Variables studied were geometry parameters of the screen disc such as mesh number and wire diameter, rotation speed, physical properties of the solution, axial flow velocity and effect of the number of closely packed screens per disc. For a single rotating screen disc contactor the rate of mass transfer was expressed by the equation:
Sh(m) = 132.63 Sc(0.33)Re(s)(0.25)Re(F)(0.3)(r(h)/d(w))(-1.38)
For rotating multi-screen discs, the mass transfer coefficient decreases by increasing the number of closely packed screens per disc. A comparison between the mass transfer behaviour of a rotating screen disc and a rotating solid disc contactor (RDC) revealed that for a given set of conditions the rate of mass transfer at the rotating screen contactor is higher than that of the rotating disc contactor by a factor of 13.8 - 28.4 depending on the operating conditions. Mechanical power consumption measurements showed that the higher the power consumption, the higher the mass transfer coefficient. Practical applications of the proposed extractor in fields such as pharmaceutical industry, hydrometallurgy, petroleum industry and water treatment were noted.