QUESTION 1: CONTINUOUS DISTILLATION [30 MARKS] It is proposed to distil a solution mixture containing 40 mol % methanol and 60 mol % water using a continuous distillation column. An overhead product is to be obtained containing 90 mol % methanol and bottom product will contain 95 mol % water. The feed is introduced at a rate of 100 kmol/hr with 30% vapourised, and a side stream is withdrawn from the column at a rate of 20 kmol/hr containing 70 mol % methanol. If the reflux ratio used is 3 times the minimum, evaluate: a) The minimum reflux b) The optimum stage for the feed c) The composition of the liquid on the third stage from the top Use the vapour-liquid equilibrium data provided below: X 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Y 0.43 0.58 0.67 0.73 0.78 0.83 0.87 0.92 0.96 Show the following clearly from the graph: Top operating line Side-stream operating line q-line Bottom operating line QUESTION 2: DRYING [20 MARKS] A batch dryer is used to dry 500 kg of wet porous solid containing 30 percent moisture. It takes 2 hours to remove 40 percent of the initial moisture content. The critical and the equilibrium moisture contents are 0.15 and 0.06 kg H20/kg dry mass respectively. Assuming the drying surface area is 0.8 m2/kg dry mass, how long will it take to dry a sample of the same solid from 0.3 to 0.1 kg H2O/kg dry mass under the same drying conditions. END--TEST Total Marks Full Marks =