A STUDY OF MASS TRANSFER INTO A LIQUID FALLING FILM IN SPIRAL TUBES USING CO2 – WATER SYSTEM

       Experimental investigation of the mass transfer characteristics of  – water system falling film in spiral tubes has been done. Several experiments were performed on the average mass transfer liquid film
coefficient ( KCO2 ) at different variables ( tube diameter d = 10 and 20  mm , water flow rate Q L = 10 – 80 liter/hr , Temperature T = 5,10,15and 20 ºC , CO 2 L gas system pressure P = 2,3,4 and 5 bar , and pitch between two turns H = 30,60 and 90 mm or the angle of inclination θ = 8.5, 16.7and 24.2 deg ) at constant coil diameter D = 100 mm , and constant tube length L = 3 m .    The experimental results indicated higher absorption rate of CO in liquids for the case of helically coiled tubes. In this results the film mass transfer  coefficient ( K ) increases with increasing film Reynolds number (ReF), also ( KL ) decreases with increasing the pitch between two turns of the coil ( or the angle of inclination ) . and it  decreases with increasing pressure of CO L gas at constant other variables, it effect only the value of the equilibrium concentration at the interface between the gas – liquid phase, but the film mass transfer coefficient is in depented on temperature of the system .