It is desired to recover hexane vapor (solute A) from air using an absorption process. The absorption solvent is a nonvolatile mineral oil, which has a mass density of 0.80 g/cm3
and a molecular weight of 180 g/gmole. In the dilute concentration range, the equilibrium relationship for the dissolution of hexane vapor in the mineral oil at 20°C is described by pA,i
= H xA,i
, where H = 0.15 atm. At the present conditions of operation, the hexane partial pressure in the bulk gas stream is 0.0 15 atm, and the dissolved hexane in the bulk absorption solvent is 5.0 mole%. The total system pressure is 1.50 atm, and the temperature is 20°C. The liquid film mass-transfer coefficient kx
is 0.01 kgmole/m2
· s, and the gas film mass-transfer coefficient is ky
a. What is the overall mass-transfer coefficient based on the liquid phase, KL, and molar flux NA?
b. What is the composition of hexane at the gasliquid inter face, in terms of pA,i and xA,i?