CHE2014: A Flash Distillation Process is Used to Separate an Equimolar Mixture of Methanol: Separation Processes 1 Assignment, SIT, Singapore

Question 1

A flash distillation process is used to separate an equimolar mixture of methanol and water at 98,000 Pa.

• By conducting a literature search, find and extract the VLE data (table) for an equimolar mixture of methanol and water at 98,000 Pa. The data must be cited (referenced) appropriately.*
• By using a graphical method, derive an appropriate operating line equation and construct/superimpose the operating line on an appropriate diagram. Determine the compositions (in mol fraction methanol) of the liquid and vapor leaving the flash separator when the feed is 30% vaporized. List any assumptions used.
• Determine the temperature of the flash separator if the feed is 30% vaporized by creating and using a suitable graph.

Question 2

• A feed stream of 180 mol/hr containing 45 mol % n-heptane and 55 mol % ethylbenzene enters a distillation column at 101.32 kPa (abs) to provide a distillate containing 96 mol % n-heptane and bottom containing 2 mol % n-heptane. Calculate the molar flow rates of the distillate and bottom (mol/hr) for this particular separation.
• By conducting a literature search, find and extract the VLE data (table) for a mixture of n-heptane and ethylbenzene at 101.32 kPa. The data must be cited (referenced) appropriately.*Construct the VLE curve and determine the vapor mole fraction of n-heptane as well as the vapor and liquid mole fractions of ethylbenzene if the liquid mole fraction of n-heptane for a binary mixture is 0.35.