Step 1. What is the number of overall gas transfer units NOG? The number of overall gas transfer units
NOG is used when calculating packing height requirements. It is a function of the extent of the desired separation and the magnitude of the driving force through the column (the displacement of the operating line from the equilibrium line).
Calculate the gas molar flow rate Gm and liquid molar flow rate Lm, in pound-moles per square foothour. The values of Gm and Lm are found on the Colburn chart (EPA-84/03, p. 104; EPA-81/12,p. 4-30). As mentioned earlier, this chart graphically predicts the value of NOG.
Calculate the cross-sectional area of the tower S, in square feet: