Measurement of mass transfer coefficients in the humidification column with random packing

Packed columns are important parts of mass and heat transfer equipments, Nowadays, using packed columns is increasing due to lower pressure drop, higher capacity and mass transfer compared with tray columns. In this survey, parameters affecting column performance were measured, these include: liquid hold up and gas-phase mass transfer coefficient in a humidification column using random packing in towers with 0.1m and 0.2m diameters and 1m height. In these experiments, liquid and gas phase were water and air, respectively. Air velocity was between 1.32 to 3.92 (m3/hr) and liquid velocity was between 10 and 70(m3/hr). In this paper, Nakajima model was used to predict the effective area. Experimental data of gas-phase mass transfer coefficient was compared with Zech, Shi, Grouff, Shulman, Billet and Onda models. Average relative errors were 7%, 15%, 29%, 21%, 45% and 195%, respectively. To predict mass transfer coefficients, Zech model was more accurate Also, by decreasing diameter of tower, gas-phase mass transfer coefficient(Kg.ae) increased.