Question

Gas mixture containing H2S and air from a petroleum distillation column, has its concentration of H2S reduced from 4.0 mol% to 0.1 mol% by scrubbing with a triethanolamine-water solvent in a countercurrent tower, operating at 300 K and at atmospheric pressure. H2S is soluble in such a solution and the equilibrium relation may be taken as Ye = 2.2X. The solvent enters the tower free of H2S and leaves containing 0.015 kmol of H2S/kmol of solvent. The overall coefficient for absorption Kya may be taken as 0.05 kmol/sm^3 of tower volume (unit driving force in Y). If the flow of inert air is 0.75 kg/m^2 s of tower cross-section and the gas-phase resistance controls the process. (Assume the gas mixture is not dilute) Calculate i) the height of the absorber necessary ii) the height of transfer units required

Answer 1