An absorber is available to treat the flue gas of Problem 3.26, which is equivalent to 8.5 equilibrium stages.

Data From Problem 3.26:-

A flue gas flows at the rate of $10 \mathrm{kmol} / \mathrm{s}$ at $298 \mathrm{~K}$ and $1 \mathrm{~atm}$ with a $\mathrm{SO}_{2}$ content of $0.15 \mathrm{~mol} \%$. Ninety percent of the sulfur dioxide is to be removed by absorption with pure water at $298 \mathrm{~K}$. The design water flow rate will be $50 \%$ higher than the minimum. Under these conditions, the equilibrium line is (Benítez, 1993) $Y_{i}=10 X_{i}$, where $Y_{i}=\mathrm{mol} \mathrm{SO}_{2} / \mathrm{mol}$ air and $X_{i}=\mathrm{mol} \mathrm{SO}_{2} / \mathrm{mol}$ water.

(a) Calculate the water flow rate and the $\mathrm{SO}_{2}$ concentration in the water leaving the absorber.

(b) Calculate the number of ideal stages required for the specified flow rates and percentage $\mathrm{SO}_{2}$ removal.