Gas containing 0.8 mol% component A is to be scrubbed with pure water in a packed bed column to reduce the concentration of A to 0.1 mol% in the exit gas. The inlet gas and water flow rates are 0.1 kmol/s and 3.0 kmol/s, respectively.
For the dilute system, both the operating and equilibrium curves are considered linear. If the slope of the equilibrium line is 24, the number of transfer units, based on the gas side, N_OG is ______ (rounded off to 1 decimal place).