Absorption of SO2, in a Tray Tower A tray tower is to be designed to absorb SO2 from an air stream by using pure water at 293 K (68F). The entering gas contains 20 mol % SO, and that leaving 2 mol % at a total pressure of 101.3 kPa. The inert air flow rate is 150 kg air/h. m^2, and the entering water flow rate is 6000 kg water/h.m. Assuming an overall tray efficiency of 25%, how many theoretical trays and actual trays are needed? Assume that the tower operates at 293 K (20C). The equilibrium condition for SO2-water system is: yA=28.029xA at 20.