The feed to a continuous distillation process is 30,000 kg/h of a mixture containing 50 wt% benzene, 30 wt% toluene and 20 wt% xylene. The distillation process consists of two columns: No. I and No. II. The feed is fed to column No. I and the overhead product from this column is X kg/h of a mixture containing 95 wt% benzene, 3 wt% toluene and 2 wt% xylene. The bottoms product from column No. I is fed to column No. II for further separation. The overhead product from column No. II is Y kg/h of a mixture containing 3 wt% benzene, 95 wt% toluene and 2 wt% xylene. The bottoms product from column No. II flows at a rate of Z kg/h and contains 1 wt% benzene, 4 wt% toluene and 95 wt% xylene.

a) Draw a block diagram and do the DOF analysis for this problem

b) Calculate X, Y, Z in kg/h.