An absorption column is used to remove pollutants from a gas by absorption into a

liquid. For this case, an absorption column is to be used to remove ammonia $(N{H}_3)$

from air by absorption into water. The information for designing the column is given

below:

The individual mass transfer coefficient based on equimolar counterdiffusion for

the liquid is estimated at $kc{L}^{\text{'}}=4\mathrm{.}0{10}^{-5}\frac{m}{s}.$

The gas film thickness is estimated at $0\mathrm{.}15mm.$

The equilibrium data for the distribution of ammonia between air and water is

such that a mole fraction of $0\mathrm{.}17$ of ammonia in water corresponds to a partial

pressure of ammonia in air of $28$kPa.

At a point in the column, the mole fraction of ammonia in water is $0\mathrm{.}010$ and the

partial pressure of ammonia in air is $20$kPa.

The absorption column operates under an overall pressure of $1$ atm and

temperature of $20C.$ Under these conditions, it can be assumed that the water

will not be vaporized and the air will not dissolve into the water.

a$)$ Determine the individual mass transfer coefficients $kc{G}^{\text{'}},k_{y^{\text{'}}}^{\text{'}},k{g}^{\text{'}}$ and $k_x.$

b$)$ Determine the flux of ammonia across the phase boundary.

c$)$ Determine the interfacial mole fractions of ammonia.

d$)$ Determine and confirm the direction of transfer of ammonia.