A toxic chemical $(A)$ will be removed from a gas mixture $(A+B)$ by gas absorption in a packed column at

constant temperature and pressure. Operational and thermophysical data are as follows: Feed flow rate

of the gas to the column is $25$kgmoles per hour; the concentration of $A$ in the inlet gas is $4$ percent by

volume. Ninety five percent of A will be removed by using pure water as absorbing liquid. Water and

carrier gas does not dissolve in each other, hence only toxic species A transfers from gas to liquid.

Equilibrium relationship at the operational condition can be represented by $y_A=2\mathrm{.}5x_A$ where $y_A$ and $x_A$

are equilibrium mole fractions of $A$ in gas and in liquid phases respectively. Find

a$)$ The minimum solvent flow rate as $k\frac{g}{h}$

b$)$ The number of overall gas transfer units $(N_{OG}=\frac{y}{}{y}_{im}^{**})$ when the actual liquid flow rate is $1\mathrm{.}25$

times the minimum liquid flow rate.

c$)$ Find a column diameter by choosing one of the materials with the characteristics below.

Data: $M{W}_L=18k\frac{g}{k}$gmol;$W_G=30k\frac{g}{k}$gmol;

${}_L=1000k\frac{g}{m^3}$;${}_G=1\mathrm{.}2k\frac{g}{m^3}$;${}_L=0\mathrm{.}01k\frac{g}{m}s.T=25C$ and $P=1$atm

Pressure drop in the packed bed must not be greater than $200P\frac{a}{m}.$

Design a column for this separation. Your choices$/$decisions must

satisfy the conditions for the concentrations and the pressure drop per

meter.$|$