.6 (Two-stage flash distillation) 3 A mixture of acetone and phenol ( 40 mass % acetone) is flashed consecutively in a cascade consisting two flash drums at 1atm. The feed enters at a rate of 3000kg/h and half of it is flashed in the first flash drum. The liquid from the first drum is heated and flashed again in the second drum. What fraction of the feed entering the second drum should be vaporized so that the residue contains not more than 1 mass % acetone? The vapour-liquid equilibrium data of the acetone-phenol system are given below