dz=KyaGm(yAyA)dyA where Gm is the molar flux of the gas, Ky is the overall mass transfer coefficient, a is the interfacial area, yA is the mol fraction of the solute in the gas phase. [4 marks] Without derivation, outline the procedure for integration of the equation in Q2(a), leading to: Z=KyaGm[GmLmmGmLm]ln[yATyAB] where yAB and yAT are the driving forces at the bottom and top of the column, Lm is the molar flux of the liquid and m is Henry's constant. [4 marks] An existing absorption column has the following operating data for removal of a low concentration solute from air flowing at the rate of 200kmolhr1m2. The partial pressure of solute gas in the inlet stream is 5000Pa and this is to be reduced to 500Pa. Fresh water is used as the wash liquid and this leaves the column containing 1000molm3 of solute. The column operates at 100kPa pressure and Henry's law constant is 1.0. The gas and liquid films mass transfer coefficients are kya=1.5103kmolhr1m3 and kxa=5.6103kmolhr1m3, respectively. The density and relative molecular mass of water are 1000kgm3 and 18kgkmol1, respectively. (i) Due to plant rearrangement, the column is to be replaced by a new column with a shorter packing height with no change of performance. The plant development engineer suggests to increase the water flow rate by 50%. Calculate the associated percentage reduction in the packing height and state your underlying assumptions. [10 marks] (ii) Suggest three other possible ways in which the packing height may be reduced and outline the limitations of each of your suggestions. [2 marks]